Electrical Connection For A Hermetic Terminal For An Active Implantable Medical Device Utilizing A Ferrule Pocket

Abstract

A feedthrough for an AIMD is described. The feedthrough includes an electrically conductive ferrule having a ferrule sidewall defining a ferrule opening. The ferrule sidewall has a height. At least one recessed pocket has a depth extending part-way through the height of the ferrule. An oxide-resistant pocket-pad is nested in the recessed pocket. An electrical connection material is supported on the pocket-pad for making an oxide-resistant electrical connection to the ferrule. An insulator is hermetically sealed to the ferrule in the ferrule opening. At least one active via hole extends through the insulator with an active conductive pathway residing in and hermetically sealed to the insulator in the active via hole.

Claims

1. A feedthrough, comprising: a) an electrically conductive ferrule, comprising: i) a ferrule sidewall defining a ferrule opening, the ferrule sidewall having a height extending to a ferrule first side end surface and a ferrule second side end surface; ii) at least one recessed pocket having a depth extending from at least one of the ferrule first side end surface and the ferrule second side end surface part-way through the height of the ferrule toward the other of the ferrule first side end surface and the ferrule second side end surface; and iii) an oxide-resistant pocket-pad nested in the at least one recessed pocket and being electrically connected to the ferrule; and b) an insulator hermetically sealed to the ferrule in the ferrule opening, the insulator extending to an insulator first side end surface at or adjacent to the ferrule first side end surface and an insulator device side end surface at or adjacent to the ferrule second side end surface; c) at least one active via hole extending through the insulator to the insulator first and second side end surfaces; and d) an active conductive pathway residing in and hermetically sealed to the insulator in the at least one active via hole.

2. The feedthrough of claim 1, wherein the oxide-resistant pocket-pad nested in the at least one recessed pocket has an upper surface that is substantially co-planar or proud of the at least one of the ferrule first side end surface and the ferrule second side end surface.

3. The feedthrough of claim 1, wherein the insulator is selected from the group of alumina, zirconia, sapphire, aluminum nitride, alumina toughened zirconia, boron nitride, ceramic-on-ceramic, partially stabilized zirconia, strontium aluminate, yttria-stabilized zirconia, zirconia toughened alumina, zirconia toughened ceramics, celsian (BaAl.sub.2Si.sub.2O.sub.8), borosilicate sealing glasses, compression sealing glasses, a Li.sub.2O×Al.sub.2O.sub.3×nSiO.sub.2 glass-ceramic system (LAS system), a MgO×Al.sub.2O.sub.3×nSiO.sub.2 glass-ceramic system (MAS system), a ZnO×Al.sub.2O.sub.3×nSiO.sub.2 glass-ceramic system (ZAS system), and combinations thereof.

4. The feedthrough of claim 1, wherein the oxide-resistant pocket-pad is selected from the group of gold, platinum, palladium, silver, iridium, rhenium, rhodium, tantalum, tungsten, niobium, zirconium, vanadium, platinum-rhodium, platinum-iridium, platinum-palladium, platinum-gold, platiniridium (platinum-iridium), iridiosmium and osmiridium (iridium-osmium), gold-palladium, gold-boron, palladium-silver, and combinations thereof.

5. The feedthrough of claim 1, wherein an electrical connection material is supported on the oxide-resistant pocket-pad opposite the ferrule.

6. The feedthrough of claim 5, wherein the electrical connection material supported on the oxide-resistant pocket-pad is proud of the at least one of the ferrule first side end surface and the ferrule second side end surface.

7. The feedthrough of claim 5, wherein the electrical connection material supported on the oxide-resistant pocket-pad is at least one of: a) a solder selected from the group of, by weight percent, Pb.sub.97.5Sn.sub.1Ag.sub.1.5, Sn.sub.10Pb.sub.88Ag.sub.2, Au.sub.82In.sub.18, Au.sub.9608Si.sub.3.2, Au.sub.98Si.sub.2, Au.sub.87.5Ge.sub.12.5, Cd.sub.95Ag.sub.5, Pb.sub.92Cd.sub.8, Pb.sub.97.5Ag.sub.1.5Sn.sub.1, Pb.sub.95Ag.sub.5, Pb.sub.94.5Ag.sub.5.5, Pb.sub.97.5Ag.sub.2.5, Pb.sub.92.5In.sub.5Au.sub.2.5, Pb.sub.92.5In.sub.5Ag.sub.2.5, Pb.sub.95.5Sn.sub.2Ag.sub.2.5, Pb.sub.93.5Sn.sub.5Ag.sub.1.5, Pb.sub.90Sn.sub.5Ag.sub.5, Pb.sub.90In.sub.5Ag.sub.5, Pb.sub.92.5Sn.sub.5Ag.sub.2.5, Pb.sub.92Sn.sub.5.5Ag.sub.2.5, Pb.sub.81In.sub.19, Pb.sub.90Sn.sub.10, Pb.sub.88Sn.sub.10Ag.sub.2, Cd.sub.82.5Zn.sub.17.5, Zn.sub.90Cd.sub.10, Zn.sub.60Cd.sub.40, Cd.sub.60Zn.sub.40, Cd.sub.70Zn.sub.30, Pb.sub.88Sn.sub.12, Pb.sub.96Sn.sub.2Ag.sub.2, Pb.sub.80Sn.sub.18Ag.sub.2, Pb.sub.75In.sub.25, Cd.sub.78Zn.sub.17Ag.sub.5, Pb.sub.70In.sub.30, Pb.sub.85Sn.sub.15, and combinations thereof; b) a thermal-setting conductive adhesive selected from the group of a conductive polymer, a conductive epoxy, a conductive silicone, or a conductive polyimide; and c) an anisotropic conductive material selected from the group of an Anisotropic Conductive Adhesive (ACA), an Anisotropic Conductive Film (ACF), an Anisotropic Conductive Paste (ACP), an anisotropic conductive tape, an anisotropic conductive epoxy, and combinations thereof.

8. The feedthrough of claim 1, wherein the at least one recessed pocket is a continuous recessed pocket surrounding the ferrule opening and the oxide-resistant pocket-pad is nested in the continuous recessed pocket.

9. The feedthrough of claim 1, wherein there are a plurality of recessed pockets at spaced locations about the ferrule opening and an oxide-resistant pocket-pad is nested in each of the plurality of recessed pockets.

10. A feedthrough that is attachable to an active implantable medical device (AIMD), the feedthrough comprising: a) an electrically conductive ferrule comprising: i) a ferrule sidewall defining a ferrule opening extending to a ferrule body fluid side end surface opposite a ferrule device side end surface; ii) at least one recessed pocket residing in at least one of the ferrule body fluid side end surface and the ferrule device side end surface; and iii) an oxide-resistant pocket-pad nested in the at least one recessed pocket and being electrically connected to the ferrule; and b) an insulator hermetically sealed to the ferrule in the ferrule opening, the insulator extending to an insulator body fluid side end surface at or adjacent to the ferrule body fluid side end surface and an insulator device side end surface at or adjacent to the ferrule device side end surface, wherein, when the ferrule hermetically sealed to the insulator is attached to an opening in a housing of an AIMD, the ferrule and insulator body fluid side end surfaces and the ferrule and insulator device side end surfaces reside outside and inside the AIMD, respectively; c) at least one active via hole extending through the insulator to the insulator body fluid and device side end surfaces; and d) an active conductive pathway residing in and hermetically sealed to the insulator in the at least one active via hole.

11. The feedthrough of claim 10, wherein the oxide-resistant pocket-pad nested in the at least one recessed pocket has an upper surface that is substantially co-planar with the at least one of the ferrule first side end surface and the ferrule second side end surface.

12. The feedthrough of claim 10, wherein the insulator is selected from the group of alumina, zirconia, sapphire, aluminum nitride, alumina toughened zirconia, boron nitride, ceramic-on-ceramic, partially stabilized zirconia, strontium aluminate, yttria-stabilized zirconia, zirconia toughened alumina, zirconia toughened ceramics, celsian (BaAl.sub.2Si.sub.2O.sub.8), borosilicate sealing glasses, compression sealing glasses, a Li.sub.2O×Al.sub.2O.sub.3×nSiO.sub.2 glass-ceramic system (LAS system), a MgO×Al.sub.2O.sub.3×nSiO.sub.2 glass-ceramic system (MAS system), a ZnO×Al.sub.2O.sub.3×nSiO.sub.2 glass-ceramic system (ZAS system), and combinations thereof.

13. The feedthrough of claim 10, wherein the oxide-resistant pocket-pad is selected from the group of gold, platinum, palladium, silver, iridium, rhenium, rhodium, tantalum, tungsten, niobium, zirconium, vanadium, platinum-rhodium, platinum-iridium, platinum-palladium, platinum-gold, platiniridium (platinum-iridium), iridiosmium and osmiridium (iridium-osmium), gold-palladium, gold-boron, palladium-silver, and combinations thereof.

14. The feedthrough of claim 10, wherein an electrical connection material is supported on the oxide-resistant pocket-pad opposite the ferrule.

15. The feedthrough of claim 14, wherein the electrical connection material supported on the oxide-resistant pocket-pad is proud of the at least one of the ferrule first side end surface and the ferrule second side end surface.

16. The feedthrough of claim 14, wherein the electrical connection material supported on the oxide-resistant pocket-pad is at least one of: a) a solder selected from the group of, by weight percent, Pb.sub.97.5Sn.sub.1Ag.sub.1.5, Sn.sub.10Pb.sub.88AG.sub.2, Au.sub.82In.sub.18, Au.sub.96.8Si.sub.3.2, Au.sub.98Si.sub.2, Au.sub.97.5Ge.sub.12.8, Cd.sub.95Ag.sub.5, Pb.sub.92Cd.sub.8, Pb.sub.97.5Ag.sub.1.5Sn.sub.1, Pb.sub.95Ag.sub.5, Pb.sub.94.5Ag.sub.5.5, Pb.sub.97.5Ag.sub.2.5, Pb.sub.92.5In.sub.5Au.sub.2.5, Pb.sub.92.5In.sub.5Ag.sub.2.5, Pb.sub.95.5Sn.sub.2Ag.sub.2.5, Pb.sub.93.5Sn.sub.5Ag.sub.1.5, Pb.sub.90Sn.sub.5Ag.sub.5, Pb.sub.90In.sub.5Ag.sub.5, Pb.sub.92.5Sn.sub.5Ag.sub.2.5, Pb.sub.92Sn.sub.5.5Ag.sub.2.5, Pb.sub.81In.sub.19, Pb.sub.90Sn.sub.10, Pb.sub.88Sn.sub.10Ag.sub.2, Cd.sub.82.5Zn.sub.17.5, Zn.sub.90Cd.sub.10, Zn.sub.60Cd.sub.40, Cd.sub.60Zn.sub.40, Cd.sub.70Zn.sub.30, Pb.sub.88Sn.sub.12, Pb.sub.96Sn.sub.2Ag.sub.2, Pb.sub.80Sn.sub.18Ag.sub.2, Pb.sub.75In.sub.25, Cd.sub.78Zn.sub.17Ag.sub.5, Pb.sub.70In.sub.30, Pb.sub.85Sn.sub.15, and combinations thereof; b) a thermal-setting conductive adhesive selected from the group of a conductive polymer, a conductive epoxy, a conductive silicone, or a conductive polyimide; and c) an anisotropic conductive material selected from the group of an Anisotropic Conductive Adhesive (ACA), an Anisotropic Conductive Film (ACF), an Anisotropic Conductive Paste (ACP), an anisotropic conductive tape, an anisotropic conductive epoxy, and combinations thereof.

17. The feedthrough of claim 10, wherein the at least one recessed pocket is a continuous recessed pocket surrounding the ferrule opening and the oxide-resistant pocket-pad is nested in the continuous recessed pocket.

18. The feedthrough of claim 10, wherein there are a plurality of recessed pockets at spaced locations about the ferrule opening and an oxide-resistant pocket-pad is nested in each of the plurality of recessed pockets.

19. The feedthrough of claim 10, wherein: a) the ferrule outermost surface comprises opposed ferrule first and second outermost surface portions meeting opposed ferrule third and fourth outermost surface portions, and b) the ferrule first and second outermost surface portions are planar and the ferrule third and fourth outermost surface portions have a radiused shape, and c) the ferrule first and second outermost surface portions are longer than the ferrule third and fourth outermost surface portions to thereby provide the ferrule having an oval shape in plan-view.

20. The feedthrough of claim 10, wherein the ferrule has either a peninsula extending inwardly into the ferrule opening or a bridge extending completely across the ferrule opening, and wherein the ferrule peninsula or the ferrule bridge has the at least one recessed pocket with a gold pocket-pad nested therein and being electrically connected to the ferrule.

21. The feedthrough of claim 10, wherein the active conductive pathway in the insulator comprises a metallic leadwire residing in the at least one active via hole where a gold braze hermetically seals the leadwire to the insulator.

22. The feedthrough of claim 10, wherein the at least one active via hole in the insulator is defined by an active via hole inner surface extending along a longitudinal axis to the insulator body fluid and device side end surfaces, and wherein the active conductive pathway residing in the at least one active via hole comprises: a) a layer of a ceramic reinforced metal composite (CRMC) comprising a mixture of alumina and platinum that contacts the active via hole inner surface, the layer of CRMC extending from a CRMC first end residing at or adjacent to the insulator device side end surface to a CRMC second end residing at or adjacent to the insulator body fluid side end surface, wherein an inner surface of the CRMC is spaced toward the longitudinal axis with respect to the via hole inner surface; and b) a substantially pure platinum material that contacts the CRMC inner surface, the substantially pure platinum material extending from a substantially pure platinum material first end residing at or adjacent to the insulator device side end surface to a substantially pure platinum material second end residing at or adjacent to the insulator body fluid side end surface.

23. The feedthrough of claim 22, wherein: a) the CRMC first and second ends and the substantially pure platinum material first and second ends extend to the respective insulator body fluid and device side end surfaces, or b) at least one of the CRMC first and second ends is recessed inwardly into the active via hole from the respective insulator body fluid and device side end surfaces, and wherein the substantially pure platinum material extends to the insulator body fluid and device side end surfaces, or c) at least one of the CRMC first and second ends is recessed inwardly into the active via hole in the insulator from the respective insulator body fluid and device side end surfaces, and wherein a corresponding at least one of the substantially pure platinum material first and second ends is recessed inwardly into the active via hole from the respective insulator body fluid and device side end surfaces, and wherein a metallic end cap extends from the at least one recessed CRMC first and second end and the correspondingly recessed substantially pure platinum material first and second end to the corresponding insulator body fluid and device side end surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The accompanying drawings illustrate the invention. In such drawings:

[0062] FIG. 1 is a wire-formed diagram of a generic human body showing a number of exemplary implantable medical devices;

[0063] FIG. 2 is a side view of a prior art cardiac pacemaker;

[0064] FIG. 2A is a wire-formed diagram illustrating how RF fields are absorbed into a lead of an implantable medical device;

[0065] FIG. 3 is an isometric cut-away view of a prior art unipolar feedthrough capacitor;

[0066] FIG. 3A is an exploded isometric view of the unipolar capacitor of FIG. 3;

[0067] FIG. 4 is a sectional view of a prior art hermetic feedthrough terminal;

[0068] FIG. 4A is an electrical schematic of the structure of FIG. 4;

[0069] FIG. 5A illustrates a quadpolar feedthrough capacitor;

[0070] FIG. 5B is a sectional view taken generally from FIG. 5B-5B from FIG. 5A, which illustrates the quadpolar feedthrough capacitor of FIG. 5A;

[0071] FIG. 6 is an exploded isometric view of the unipolar capacitor previously illustrated in FIGS. 5A and 5B;

[0072] FIG. 7 is the schematic drawing of the feedthrough capacitor of FIGS. 5A-5B;

[0073] FIG. 8 illustrates a prior art rectangular feedthrough capacitor, which has the same number of poles (4, quadpolar) as previously illustrated in FIG. 4A;

[0074] FIG. 9 is an isometric view illustrating the hermetic seal subassembly ready to receive the capacitor of FIG. 8;

[0075] FIG. 10 is taken generally from section 10-10 from FIG. 8 showing the active electrode plates;

[0076] FIG. 11 is taken generally from section 11-11 from FIG. 8 showing the ground electrode plate;

[0077] FIG. 12 illustrates the feedthrough capacitor installed to the hermetic seal assembly as previously described in FIGS. 8 and 9;

[0078] FIG. 13 is a sectional view taken generally from section 13-13 from FIG. 12;

[0079] FIG. 14 is an electrical schematic diagram illustrating the undesirable presence of an oxide in the ground path of the quadpolar feedthrough capacitor;

[0080] FIG. 15 shows the use of novel gold braze bond pads that are one embodiment of a novel feature of the '596 patent;

[0081] FIG. 16 shows that the feedthrough capacitor ground metallization is electrically attached by a thermal-setting conductive adhesive directly to the gold bond pad area;

[0082] FIG. 17 is a sectional view taken from section 17-17 from FIG. 16;

[0083] FIG. 18 is an isometric view taken from FIG. 23 of the '779 patent;

[0084] FIG. 19 is a sectional view of the structure of FIG. 18 taken along lines 19-19;

[0085] FIG. 19A illustrates filter performance otherwise known as attenuation or insertion loss curves versus frequency;

[0086] FIG. 20A illustrates sectional isometric view of a prior art feedthrough;

[0087] FIG. 20B is a sectional view of a prior art feedthrough;

[0088] FIG. 20C is an exploded sectional view of a prior art feedthrough;

[0089] FIG. 20D is an exploded sectional view of a prior art feedthrough;

[0090] FIG. 21A is an isometric view of just a ferrule that can be used with the present invention;

[0091] FIG. 21B is a sectional view of one embodiment of a ferrule taken along lines 21B-21B from FIG. 21A;

[0092] FIG. 21C is a sectional view of another embodiment of the ferrule taken along lines 21C-21C from FIG. 21A;

[0093] FIG. 21D is an isometric view of just an insulator that can be used with the present invention;

[0094] FIG. 21E is a sectional view taken along lines 21E-21E of FIG. 21D;

[0095] FIG. 21F is an isometric exploded view of a feedthrough before the present invention capacitor is attached;

[0096] FIG. 22 is an isometric view of the present invention where the capacitor overhangs the ferrule edge on two edges for an increased effective capacitance area;

[0097] FIG. 22A is a sectional isometric view taken along lines 22A-22A from FIG. 22;

[0098] FIG. 22B is a sectional isometric view taken along lines 22B-22B from FIG. 22;

[0099] FIG. 22C is a sectional isometric view taken along lines 22C-22C from FIG. 22;

[0100] FIG. 22D is a sectional isometric view taken along lines 22D-22D from FIG. 22;

[0101] FIG. 22E is a side view taken along lines 22E-22E from FIG. 22;

[0102] FIG. 22F is a side view taken along lines 22F-22F from FIG. 22;

[0103] FIG. 22G is an isometric view of another embodiment of the present invention where now the capacitor only overhangs the ferrule along one edge of the ferrule;

[0104] FIG. 22H is a side view taken along lines 22H-22H from FIG. 22G;

[0105] FIG. 22I is a side view taken along lines 22I-221 from FIG. 22G;

[0106] FIG. 22J is a side view similar to FIG. 22H now showing a new embodiment similar to FIG. 22G where the capacitor is aligned along the left side;

[0107] FIG. 22K is a side view similar to FIG. 22I if it was taken of the structure of FIG. 22J along the lines 22H-22H of FIG. 22G;

[0108] FIG. 22L is a sectional view of the active electrode plates taken along lines 22L-22L of FIG. 22E;

[0109] FIG. 22M is a sectional view of the active electrode plates taken along lines 22M-22M of FIG. 22H;

[0110] FIG. 22N is a sectional view of the active electrode plates taken along lines 22N-22N of FIG. 22J;

[0111] FIG. 22O is a simplified top view illustrating one embodiment of the capacitor overhanging the ferrule;

[0112] FIG. 22P is a simplified top view illustrating another embodiment of the capacitor overhanging the ferrule;

[0113] FIG. 22Q is a simplified top view illustrating another embodiment of the capacitor overhanging the ferrule;

[0114] FIG. 22R is a simplified top view illustrating another embodiment of the capacitor overhanging the ferrule;

[0115] FIG. 22S is a simplified top view illustrating another embodiment of the capacitor overhanging the ferrule;

[0116] FIG. 22T is a simplified top view illustrating another embodiment of the capacitor overhanging the ferrule;

[0117] FIG. 22U is a simplified top view illustrating another embodiment of the capacitor overhanging the ferrule;

[0118] FIG. 22V is a simplified top view illustrating another embodiment of the capacitor overhanging the ferrule;

[0119] FIG. 22W is a simplified top view illustrating another embodiment of the capacitor overhanging the ferrule;

[0120] FIG. 23 is an isometric view of another embodiment of the present invention now having gold pocket-pads;

[0121] FIG. 23A is an enlarged isometric view of another embodiment of a pocket with an oxide-resistant metal trough or an oxide-resistant metal addition such as platinum wire for grounding;

[0122] FIG. 24 is an isometric view of the present invention similar to FIG. 23 now with an overhanging capacitor;

[0123] FIG. 24A is a sectional isometric view taken along lines 24A-24A from FIG. 24;

[0124] FIG. 24B is a sectional isometric view taken along lines 24B-24B from FIG. 24;

[0125] FIG. 24C is a side view taken along lines 24C-24C from FIG. 24;

[0126] FIG. 24D is a side view taken along lines 24D-24D from FIG. 24;

[0127] FIG. 25 is an exploded isometric view of another embodiment of the present invention;

[0128] FIG. 26 is an isometric view of the structure of FIG. 25 now with the capacitor installed;

[0129] FIG. 26A is an isometric view taken along lines 26A-26A from FIG. 26;

[0130] FIG. 26B is an isometric view taken along lines 26B-26B from FIG. 26;

[0131] FIG. 26C is an isometric view taken along lines 26C-26C from FIG. 26;

[0132] FIG. 26D is an isometric view taken along lines 26D-26D from FIG. 26;

[0133] FIG. 27 is an electrical schematic of the structure of FIG. 26;

[0134] FIG. 28 illustrates an isometric view of a hybrid feedthrough capacitor of the present invention;

[0135] FIG. 29 is a sectional view of a ground electrode plate taken along lines 29-29 of FIG. 28;

[0136] FIG. 30 is a sectional view of a ground electrode plate taken along lines 30-30 of FIG. 28;

[0137] FIG. 31 illustrates an isometric view of a feedthrough assembly having a bridge for an internal ground attachment and a gold pocket-pad for an external ground attachment to use with the capacitor of the present invention;

[0138] FIG. 32 is a top view of the structure of FIG. 32 taken along lines 32-32;

[0139] FIG. 33 is a sectional side view taken along lines 33-33 from FIG. 32;

[0140] FIG. 34 illustrates an isometric view of a feedthrough assembly having a peninsula for an internal ground attachment and a gold pocket-pad for an external ground attachment to use with the capacitor of the present invention;

[0141] FIG. 35 is a top view of the structure of FIG. 34 taken along lines 35-35;

[0142] FIG. 36 is a sectional side view taken along lines 36-36 from FIG. 34;

[0143] FIG. 37 is an isometric view of another embodiment of the present invention now having a leadwire comprised of different materials;

[0144] FIG. 38 is a sectional side view taken along lines 38-38 from FIG. 37;

[0145] FIG. 38A is similar to FIG. 38 but is another embodiment of a leadwire comprised of different materials;

[0146] FIG. 39 is a sectional view of a feedthrough having a peninsula with a gold pocket-pad for an internally ground capacitor;

[0147] FIG. 40 is a sectional view similar to FIG. 39 now having an internally ground capacitor placed thereon;

[0148] FIG. 41 is a sectional view similar to FIG. 40 now showing an internally grounded capacitor grounded the oxide-resistant gold braze hermetic seal;

[0149] FIG. 42 illustrates a sectional side view of another embodiment of the present invention similar to FIG. 41 now having an internally grounded capacitor that is ground to a gold pocket-pad along the ferrule perimeter;

[0150] FIG. 43 is very similar to FIG. 42 but now uses an ACF film for making electrical connections;

[0151] FIG. 44 is an enlarged view taken along lines 44-44 of FIG. 43;

[0152] FIG. 45 is an enlarged sectional view of the oxide-resistant (gold) pocket-pad of FIG. 42;

[0153] FIG. 46A is a sectional view of an embodiment of a ferrule perimeter or a ferrule edge having an oxide-resistant (such as gold) pocket-pad on the device side of a ferrule;

[0154] FIG. 46B is a sectional view of an embodiment of a ferrule perimeter or a ferrule edge having an oxide-resistant (such as gold) pocket-pad on the body fluid side of a ferrule;

[0155] FIG. 46C illustrates a top view of feedthrough having a rectangular ferrule and a perimeter pocket-pad and a cross-sectional view illustrating the ferrule height and the depth of the pocket;

[0156] FIG. 46D illustrates a top view of a feedthrough having a discoidal ferrule with three pocket-pads and a cross-sectional view illustrating the ferrule height and the depth of the pockets; and

[0157] FIG. 47 is a chart detailing various solder compositions that may be used to attach to a ferrule pocket.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0158] In some of the following figure descriptions herein, reference axes are included to be helpful in understanding the present invention (see for example FIG. 21). In particular these are orthogonal axes with an x, y and z axis shown in the figures to provide a reference for the reviewer for increased understanding of the present invention. As used herein, the z axis may also be referred to as the longitudinal axis. In cross-sections the axes will appear as either z, y or z, x axes views, which is consistent with isometric geometry.

[0159] FIG. 21A illustrates a rectangular ferrule structure 112 for an AIMD that is typically made of titanium. As shown herein, the ferrule is without an insulator 160 and without leadwires 111. There are four imaginary planes, as illustrated, extending upward above the ferrule 112. These imaginary planes extend from the outermost perimeter edge of the ferrule and embody in the y-z axis, ferrule plane FP.sub.L1 and FP.sub.L2. There are also two planes extending in the x-z plane and these are the ferrule with planes FP.sub.W1 and FP.sub.W2.

[0160] Jumping ahead to FIG. 21F, one can see that an insulator 160 of FIG. 21D is configured to be installed in the ferrule opening 306. The insulator has four passageways that are also known as insulator via holes 316. As shown, the insulator has a device side end surface 314 which is opposite the insulator body fluid side end surface 312.

[0161] FIG. 21B illustrates a modified ferrule 112, as previously depicted in FIG. 21A. There is a center line CL shown, with an arrow indicating the lateral direction. As can be seen, the lateral direction is perpendicular to the axis of the center line CL. A ferrule inner surface 307 is defined as shown. In this embodiment the inner surface 307 is relatively simply in shape, but it is understood by those skilled in the art that it could comprise numerous surfaces. A ferrule outermost surface 302, 304 is also indicated. It is understood that in one direction the outermost surface may be indicated as 302 and in a perpendicular direction the outermost surface may be indicated as 304. Referring again to the ferrule outermost surfaces 302, 304, one can see that ferrules often have complex shapes, including, in this case, surfaces 303 and 305. For the purposes of the present invention, that which will be the outermost, meaning the surface of the ferrule that extends in the lateral direction furthest from the center line, is defined as the ferrule outermost surface 302, 304. Accordingly, the surfaces 303 and 305 are not the outermost. A ferrule device side end surface 310 is also defined as shown. The ferrule side wall 309 is defined as including all of the projections and irregularities of the ferrule side wall which would include, in this case, the outermost surface 302, 304 and other features, such as 303 and 305. In other words, the ferrule side wall 309 comprises the entire side wall and all of its features whether outermost or not. The ferrule also has a body fluid side end surface 308, as shown. The ferrule also comprises a ferrule opening 306, as shown. As is understood by those skilled in the art, the ferrule opening 306 is configured to receive an insulator structure 160. Referring once again to FIG. 21B, one will see that there is an imaginary projection 334 shown projected (perpendicular to surface 310) aligned with the ferrule outermost surface 302, 304. This imaginary projection 334 is helpful in later figures to understand how a feedthrough capacitor will be disposed in an overhanging relationship to the ferrule.

[0162] FIG. 21C is very similar to FIG. 21B but illustrates that ferrules 112 can take on various shapes. In this case, the ferrule outermost surface 302, 304 is not necessarily disposed contiguous with the ferrule device side end surface. Rather, the ferrule outermost surface 302, 304 is between surfaces 303 and 305. Yet, the imaginary ferrule projection 334 is from the ferrule outermost surface 302, 304, no matter where it occurs along the ferrule side wall 309. It is also understood by those skilled in the art that ferrules are typically made of titanium and are always electrically conductive. However, other suitable materials for a ferrule are possible as this teaching is not limited to just a titanium ferrule.

[0163] The ferrule outermost surface 302 is defined herein as a first outermost surface but which can also be called a first outermost edge. Likewise, the ferrule outermost surface 304 is defined as a second outermost surface but which can also be called a second outermost edge. It is noted that the surfaces/edges 302 and 304 are perpendicular to each other in the case of a rectangular shaped ferrule.

[0164] FIG. 21D shows an alumina ceramic insulator 160 that has been configured such that it will fit into the ferrule opening 306, as previously described in FIGS. 21A, 21B and 21C. In this particular case, the insulator has four passageways 316. Referring now to cross-sectional view 21E-21E taken from FIG. 21D, one can see these passageways are active passageways meaning that they are going to receive terminal pins that pass from a body fluid side to a device side of the AIMD. Again, referring to FIG. 21E, there is an active hole inner surface 318, as shown. The insulator body fluid side end surface 312 is indicated and the insulator device side end surface 314 is also indicated. In general, when the insulator is installed in a ferrule 112 and the ferrule is installed in an AIMD housing 116, the device end surface 314 will be the side that is directed toward the inside of the AIMD housing and the insulator body fluid side end surface 312 will be that side that is directed towards the body fluid side of the AIMD.

[0165] FIG. 21F illustrates a rectangular quadpolar hermetic feedthrough 120. One can see that there is a ferrule structure 112 that has been gold brazed 150 to a generally alumina ceramic insulator 160. (The alumina ceramic insulator 160 was previously described in FIGS. 21D and 21E.) There are also four leadwires (i.e. pins or leads) 111, 114 which are also gold brazed 162 to the alumina insulator 160. It will be noted that the through-pins, which are solid conductors, are labeled 111 on the device side and 114 on the body fluid side. Accordingly, even those these leadwires are solid, they can be described as having a device side portion 111 and a body fluid side portion 114. As used and defined herein, the word “portion” does not mean that a structure, such as a leadwire, has to have two different parts. Rather, it rather means that it has two different ends. However, as shown in later figures the leadwire itself may be made from differing materials to save cost.

[0166] FIG. 21F also illustrates the feedthrough capacitor 132 coming down and being mounted “adjacent” the ferrule 112, such that the feedthrough capacitor can be directly mounted onto one of the ferrule and/or the insulator, as previously illustrated in FIG. 4 or it can be spaced away from one of the insulator and the ferrule with an insulative washer 212, as previously illustrated in FIG. 13. The feedthrough capacitor 132 could even be spaced away from either the insulator or the ferrule by an air gap. As used herein, the word “adjacent” is not limited to touching, rather “adjacent” includes being right near and/or mounted directly onto a structure, being spaced from with an air gap or also spaced with a washer there between.

[0167] Referring once again to FIG. 21F, the leadwires 111, 114 are also defined herein as comprising active conductive pathways that reside in and are hermetically sealed to the insulator 160, in the at least one active insulator via hole 316, as previously described in FIG. 21D. Skipping ahead to FIGS. 39-45, the insulator structure 160 may comprise a ceramic reinforced co-sintered metal 185 with platinum co-sintered end caps 186. The active conductive pathway residing in and hermetically sealed to the insulator need not always comprise a leadwire as shown in FIG. 21F, but can comprise any of the structures, as defined in any of the drawings herein.

[0168] FIG. 22 illustrates a rectangular (or could be square, circular, rounded, oval or some combination thereof) feedthrough capacitor 132 mounted to the hermetic terminal feedthrough assembly 120 of FIG. 21. The feedthrough capacitor 132 has a unique geometry and for the first time, overhangs both sides of the ferrule in the x direction. However, in this embodiment the feedthrough capacitor is designed to not overhang the ferrule in the y direction. In fact, the y dimension of the feedthrough capacitor is specifically designed such that the electrical connection material 152 between the capacitor ground metallization 142 and the ferrule will hit the oxide-resistant exposed gold braze 150, as illustrated.

[0169] Referring once again to FIG. 22, a global ground electrical connection 192 is defined. As defined herein, a ground electrical connection 192, as illustrated in FIG. 22, may comprise a ground electrode plate set electrically connected to the capacitor ground metallization 142. Then, either a thermal-setting conductive adhesive, or a solder or the like 152 is used to electrically connect the capacitor ground metallization 142 to the ferrule 112. As previously discussed, ferrule structures 112 are typically of titanium and may be oxidized. Accordingly, in the present invention, the global electrical connection 192 would include connection to the hermetic seal of the gold braze 150, as illustrated, which is an oxide-resistant and bio-stable surface. Alternatively, the global electrical connection may be to gold pocket-pads in the ferrule, as will be described in FIGS. 23 and 23A herein. The global electrical connection 192 may also comprise one or more internally grounded feedthrough passageways that will be described in detail herein, in FIGS. 26 and 26A.

[0170] Again, the global use of the ground electrical connection or electrically conductive path 192 may include a hybrid grounded capacitor, as illustrated in FIG. 28, and is shown attached to a ferrule in FIGS. 31 and 32. This embodiment is known as a hybrid ground in that, one of the feedthrough capacitor passageways is grounded. In other words, attached electrically connected to the ground electrode plates and the ground electrode plates are also brought out to external metallizations. This hybrid grounding system globally is still called 192, but combines exterior electrical metallizations, as well as a grounded passageway.

[0171] The novel configuration as illustrated in FIG. 22 illustrates several important principles: 1) an oxide-resistant metal connection 152 is made between the ground metallization 142 of the feedthrough capacitor to the gold braze 150; and 2) in the x direction, the feedthrough capacitor is actually wider than the ferrule, which greatly increases the effective capacitance area (ECA) of each one of the four filter capacitors. The present invention results in an amazing increase of volumetric efficiency for the device.

[0172] Referring once again to FIG. 22, it is not really practical to reverse the geometry, that is, make the capacitor relatively thin in the x axis and overhanging the long in the y axis. The problem with this reversal is that the ECA of each of the four capacitors would be significantly reduced. It will be appreciated that this could be done under the present invention, but would not be a preferred embodiment.

[0173] A recent driving factor behind having a capacitor overhang in one axis (in this case, the x axis) and not overhang in the y axis has to do with the need for an oxide-resistant ground electrical connection 192 while at the same time, increasing the capacitor's ECA. As previously mentioned, with the number of leads constantly increasing, there is a constant need for improvements in volumetric efficiency, which increased ECA provides. Increasing the ECA also enables the use of lower k dielectrics, such as those taught by U.S. Pat. Nos. 9,764,129; and 10,092,749, the contents of which are included in full herein by reference.

[0174] FIG. 22A is taken generally from section 22A-22A from FIG. 22. FIG. 22A is sliced through the capacitor exactly along the perimeter edge (y-z plane) of the ferrule. This is why the ferrule is not shown cross-sectioned in FIG. 22A. The internal electrode plates of the feedthrough capacitor 132 have been exposed, such that one can see the active electrodes 148 and the ground electrodes 146, which run from one end of the capacitor to the other in the y direction and are connected to an external capacitor metallization 142. One can also clearly see the electrical connection 152 between the capacitor ground metallization 142 and the gold braze of the hermetic seal.

[0175] FIG. 22B is taken from section 22B-22B of FIG. 22, which is very similar to FIG. 22A, except this time, the section line, which is along the y axis, goes through two (C.sub.3, C.sub.4) of the active leadwire or lead pins. One can see that there are two sets of active electrodes 148 and 148′, which are each conductively connected to the two associated leadwires. It will be understood that there are actually four sets of active electrode plates with two other sets being associated with the two other leads (C.sub.1, C.sub.2) through which the section does not pass. Also shown is the ground electrode plate 146, again, connecting from ground metallization 142 on each end of the capacitor. Referring once again to FIGS. 22A and 22B, it will be appreciated that both ends of the capacitor ground metallization 142 are connected with an electrical connection material 152 to sections of the hermetic seal gold braze 150, as illustrated. In this view, the metallization and gold braze is not shown on the insulator for simplicity.

[0176] Referring again to FIG. 22B and as defined herein, there is a first electrical connection material 156 that connects the active conductive pathway residing in the at least one active via hole in the insulator to the active metallization electrically connected to the at least one active electrode plate of the feedthrough capacitor. Also defined is a second electrical connection material 152 that electrically connects the capacitor ground metallization 142 connected to the at least one ground electrode plate of the feedthrough capacitor to the ferrule. These definitions do not mean that the electrical connection material 152 is connected only to the ferrule but can be connected to the ferrule through an intermediate material, such as a gold braze and the like, as previously described.

[0177] FIG. 22C is taken from section 22C-22C from FIG. 22 and is a sectional view generally taken along the x axis through pins C.sub.1 and C.sub.4. In this view, one can clearly see how the quadpolar feedthrough capacitor 132 overhangs the perimeter edges of the ferrule in the x direction. One can clearly see the active electrode plates 148′ and in this case, 148″, each associated with a leadwire 111.

[0178] FIG. 22C better illustrates two of the via holes in cross-section. One can see that the via holes 316 have an active via hole inner surface 318 as best seen in FIG. 21E. This active via hole inner surface 318 might be sputtered (metallized) after the insulator 160 is sintered, such that there is an adhesion layer 153 and wetting layer 151 suitable to accept a gold braze. In other embodiments, the passageway 316 may be filled by a substantially pure platinum via or a ceramic reinforced metal composite, as will be further described herein. In these cases, the conductive via passageway 316 would be co-sintered at the same time as the alumina insulator 160.

[0179] There is an active conductive pathway 320 that is formed through the insulator structure. This active conductive pathway can take the form of a leadwire, as illustrated in FIGS. 4, 9, 13 or it may take the form of any of the substantially pure platinum or ceramic reinforced metal composite co-sintered vias, as illustrated in FIGS. 39-45. Referring now back to FIGS. 22C, 22E, 22F and 22H to 22K, one can see that the feedthrough capacitor has a device side end surface 324 and a side of the capacitor 326 that is near or adjacent the ferrule. There is at least one active passageway 328 extending through the capacitor dielectric between the capacitor first and second surfaces 324 and 326. It will be appreciated that this conductive passageway, in many embodiments, extends outwardly beyond either capacitor surface 324, 326 or both. Also, the conductive pathway may extend beyond at least one of the ferrule device side or the ferrule body fluid side or both.

[0180] FIG. 22D is taken from 22D-22D from FIG. 22 and is very similar to FIG. 22C, except in this case, it does not cut through any of the active leadwire pins. This sectional cut is also taken in the margin area between active electrodes 148, such that none of the active electrodes are shown in FIG. 22D. Accordingly, the only electrodes that we can see in this view are ground electrodes 146. In FIG. 22D, one can see one of the novel aspects of the present invention that is where the capacitor overhangs the ferrule and where the ground electrodes 146 do not need to extend to the outer edges of the feedthrough capacitor. These outer edges are the parts of the overhanging capacitor in the y-z plane that overhang the ferrule.

[0181] FIG. 22E is a side view taken from isometric 22E-22E from FIG. 22. This is not a sectional view but illustrates the overhanging capacitor 132. As properly noted in FIG. 22E, this is drawn in the x-z plane. The perimeter edge of the ferrule is illustrated by line A-A. Line A-A is best thought of as a plane that goes in and out of the paper along the perimeter edge of the ferrule, as illustrated. One can clearly see the present invention in FIG. 22E, as the overhang 200, which overhangs line A-A. As illustrated in FIG. 22E, this overhang 200′, 200″ is on both sides. It will be appreciated that the overhang could be only on one side, but this would reduce the effective capacitance area of the two associated leadwires that are not on the overhanging side.

[0182] FIG. 22F is another side view taken from isometric 22F-22F from FIG. 22. Again, in this case, there is no cross-hatching, and this shows the side view taken in the y-z plane. Again, an imaginary line B-B is shown along the edge of the capacitor which could also be thought of as a plane extending into and out of the paper. Importantly, in accordance with the present invention, there is a setback (spaced inwardly) 201′ and 201″, as illustrated. As will be seen in every embodiment, the setback 201 also enables an oxide-resistant conductive connection to the ferrule. In summary, the FIG. 22 series illustrates the present invention, in that, there is always a portion of the feedthrough capacitor perimeter that overhangs the ferrule (which increases the ECA) and there is also always a portion of the feedthrough capacitor perimeter that is setback (does not overhang) a portion of the ferrule perimeter or is aligned with the ferrule perimeter. In general, this setback area enables an oxide-resistant electrical connection generally to a gold or other noble surface.

[0183] Referring once again to FIGS. 22E and 22F, one can see that there is a line C-C, which in both cases can become a plane by imagining it extended in and out of the paper. This is the plane between the capacitor 132 and the ferrule and insulator 112, 160. It will be appreciated that the capacitor may lay directly against the insulator, the ferrule or both the insulator and the ferrule, or even that the capacitor may be spaced some distance away from the insulator and/or the ferrule by means of an adhesive washer, a spacer, an air gap or the like. Referring once again to FIG. 22E, one will also appreciate that in the present invention, the capacitor overhang area 200 may coincide substantially with line or plane A-A. By aligning the capacitor overhang edge 200 with the perimeter edge of the ferrule A-A, one still gains a substantial amount of ECA. Importantly, it is still necessary to have a setback 201, as illustrated in FIG. 22F, so that one can accomplish an oxide-resistant electrical ground connection 152.

[0184] Referring back to the imaginary projections of FIG. 21A, the imaginary projection planes FPL1, FPL2, FPW1 and FPW2 onto the capacitor dielectric second end surface 326 defines: at least one capacitor dielectric imaginary first overhang portion 200′ or 200′ or both 200′ or 200′ extending laterally outwardly beyond the ferrule outmost surface 302; and a capacitor dielectric imaginary second overlay portion 203 that overlays the ferrule device side end surface and overlays the hermetically sealed insulator, wherein, at least part of the capacitor dielectric outer side wall in the capacitor dielectric imaginary second overlay portion is spaced inwardly 201′ or 201″ from the ferrule outermost surface 304 and wherein, the at least one ground electrode plate at least partially resides in the capacitor dielectric imaginary second overlay portion.

[0185] FIG. 22G is very similar to FIG. 22, except that the feedthrough capacitor 132 only overhangs the ferrule 112 on one side, as illustrated. This is best illustrated in FIG. 22H where one can see that the feedthrough capacitor overhang portion 330 only overhangs on the right side of the ferrule and not the left side.

[0186] FIG. 22I is essentially the same as FIG. 22F, which illustrates that the feedthrough capacitor is spaced inwardly on both the right and the left sides from the ferrule outermost surface 304.

[0187] FIG. 22J is very similar to FIG. 22H, except on the left side, the capacitor is aligned with the ferrule outermost surface 302, as indicated. So, in this case, the capacitor is overhanging on the right side 330 and is aligned on the left side.

[0188] FIG. 22K is exactly the same as FIG. 22I because from this perspective, they are both the same.

[0189] FIG. 22L illustrates the active electrode plates of the capacitor illustrated in FIGS. 22 and 22E. One can see that the active electrodes of all four of the quad polar capacitors are equal in this view.

[0190] FIG. 22M illustrates the active electrodes of the feedthrough capacitor of FIG. 22H that only overhangs on one side. The overhang on the one side makes the active electrodes on that side much larger and hence the capacitor value is larger. By only overhanging on one side, however, the effective capacitance area where active electrode plates become smaller. Referring once again to FIG. 22H, this means that the capacitors for the leadwires on the left is lower than the capacitance for the leadwires 111 on the right.

[0191] FIG. 22N illustrates the active electrode plates taken from FIGS. 22J and 22K. In this case, the four-quad polar leadwires are inline. Again, because the capacitor is overhanging on one side and not the other, this results in asymmetry of the active electrode plates, as indicated. This asymmetry is not a disadvantage in that, the effective capacitance area or electrode plate area is equal for all four of the active electrodes.

[0192] FIGS. 22O through 22W indicate various alignments of the capacitor 132 (shown with a solid line) as it overlays the top view of the ferrule 112 (indicated by the dash lines). In accordance with the present invention, as illustrated in FIG. 22O, the feedthrough capacitor need only overhang one side or portion of the ferrule. It is also important that the capacitor be set back or not overhang at least a portion of the ferrule.

[0193] In particular FIG. 22R illustrates perhaps the most likely form of the present invention wherein, the feedthrough capacitor overhangs opposite sides of the ferrule and is held back or set back from the other two sides of the ferrule. This allows for a proper ground attachment to a gold braze and in turn, to the ferrule while at the same time, allows for the resulting active electrode plates to all be equal and therefore, result in equal filter performance for each of the leads. Having equal filter performance on each of the leads is the common practice in the AIMD industry.

[0194] FIG. 23 is an isometric view of a hermetic seal subassembly 120 similar to that previously described in FIG. 21F. As one can see, there is a gold braze 150 between ferrule 112 and insulator 160. It will be appreciated that one can only extend this gold braze 150 outwardly so much before it would interfere with the can half clam shell mating structure 163. One can see that four novel oxide-resistant gold-filled pockets 248 (250) have been formed. In general, these pockets are like little swimming pools that are machined or formed at the time that the ferrule 112 is formed. Then, at the same time that gold brazes 150 and 162 are formed, gold preforms 250 are reflowed, creating four oxide-resistant noble metal attachment surfaces. It is noted that the oxide-resistant gold-filled pockets of FIG. 23 provides a ferrule gold pocket-pad; however, it is understood by one of skill in the art that the oxide-resistant material of the ferrule pocket-pad of FIG. 23 may be selected from the group consisting of gold, platinum, palladium, silver, iridium, rhenium, rhodium, tantalum, tungsten, niobium, zirconium, vanadium, and combinations or alloys thereof.

[0195] Referring back to FIG. 23, it will be appreciated that the gold pocket-pads 248, 250 can be joined on each end into a trough into which a small diameter gold wire is placed prior to gold brazing. This is best illustrated in FIG. 23A, which is taken from section 23A-23A from FIG. 23. Shown is a small diameter gold wire 250 ready to be placed into an elongated gold pocket receptacle 248. In general, gold braze 250 is reflowed at the same time that the hermetic seal gold brazes 150 and 162 are formed. Alternatively, wire 250 may comprise an oxide-resistant metal addition such as a brazed or laser welded gold, platinum, palladium, silver, and combinations thereof. Additionally, the wire 250 may further comprise a clip, a pad, an L-shaped pad, and an L-shaped pad with cutouts. Wire 250 may comprise any of the metal additions described in U.S. Pat. No. 9,931,514, the contents of which are incorporated fully herein by reference.

[0196] FIG. 23 was taken from FIG. 25 of U.S. patent application Ser. No. 15/943,998, the contents of which are incorporated in full herein. A major advantage of these pocket-pads is that much less gold braze is required to form the hermetic seal 150 between the ferrule 112 and insulator 160. In addition, the gold pocket-pads are so thin that they can be placed right over the can capture area 163.

[0197] FIG. 24 illustrates a quadpolar feedthrough capacitor 132 mounted to the hermetic seal with gold pocket-pads of FIG. 23. This allows the feedthrough capacitor to be wider CW.sub.1. In accordance with the present invention, the feedthrough capacitor 132 overhangs the outermost perimeter of the ferrule FW.sub.1 as indicated. This is known as the capacitor overhang area. This capacitor overhang area is generally oriented in the x direction. When one looks at they direction, one will see that the capacitor 132 is setback from the edge of the ferrule perimeter. In other words, dimension CW.sub.2 is either less than or substantially equal to FW.sub.2. In summary, in accordance with the present invention, the feedthrough capacitor of FIG. 24 overhangs in the x direction and is setback (or aligned) in the y direction. Also, in accordance with the present invention, an oxide-resistant electrical connection 142 is made between the feedthrough capacitor ground metallization 142 and each of the four gold pocket-pad 248, 250 as indicated with electrical connection material 152. It will be appreciated that the number of gold pocket-pads can be increased, decreased or even merged together. It will also be appreciated that the electrical connection material 152 can comprise thermal-setting conductive adhesive, a solder, a braze or the like.

[0198] FIG. 24A is taken from section 24A-24A from FIG. 24. FIG. 24A illustrates that the feedthrough capacitor 132 is setback on both of its sides from the ferrule width FW.sub.2. This is also illustrated in FIG. 24B.

[0199] FIG. 24C is a side view taken from 24C-24C from FIG. 24. This is very similar to FIG. 22E, except that the electrical connections are to the gold pocket-pads and not to the hermetic seal gold braze.

[0200] FIG. 24D is a side view taken from 24D-24D from FIG. 24. This figure is very similar to FIG. 22F and illustrates that the capacitor is setback in its width from the ferrule. In summary, FIG. 24C illustrates the side (pictorial) view in the x-z plane clearly illustrating that the feedthrough capacitor 132 overhangs 200 ferrule 112. As mentioned in FIG. 24D, the capacitor can be substantially aligned with the edge of the ferrule or setback 201, as illustrated.

[0201] FIG. 25 is an internally grounded capacitor with a ferrule peninsula 139. An internally grounded capacitor with a ferrule peninsula is taught in FIGS. 11a, 11b and 11c in U.S. patent application Ser. No. 15/863,194, the contents of which are incorporated herein fully be reference. Referring back to FIG. 25, one can see that in the x-z direction, the feedthrough capacitor 132 overhangs the ferrule 112.

[0202] This is best illustrated in FIG. 26, where one can see the feedthrough capacitor mounted to the ferrule, wherein the feedthrough capacitor clearly overhangs the width of the ferrule in the x-z plane. It will also be noted that this feedthrough capacitor, since it is internally grounded, has no external or perimeter electrical metallization or electrical connection to the ferrule. The entire grounding of the feedthrough capacitor internal ground electrodes are through internal ground leadwire 111gnd. Accordingly, the feedthrough capacitor is also not constrained in the y-z orientation either. In this case, the feedthrough capacitor is shown nearly aligned with the outermost edge of the length of the ferrule and overhang substantially along the width of the ferrule.

[0203] FIG. 26A is taken from section 26A-26A from FIG. 26. FIG. 26A is drawn in the x-z plane clearly showing how the internally grounded feedthrough capacitor 132 overhangs the widest width of the ferrule 112. FIG. 26A is sectioned through one of the active pins 111 and shows that it is electrically connected 156 to active metallization 144, which is connected to its active electrode plates 148, as shown.

[0204] FIG. 26B is taken from section 26B-26B from FIG. 26 and is very similar to FIG. 26A, except that this is sectioned through the ground pin 111gnd. One can see that the ground pin is gold brazed 150′ into the ferrule 122 peninsula structure 139 as indicated. FIG. 26B also shows that the ground pin 111gnd is connected to the corresponding set of capacitor ground electrode plates 126.

[0205] FIG. 26C is very similar to FIGS. 26A and 26B and is taken generally from section 26C-26C from FIG. 26. In this case, the sectioning is through ground pin 111gnd. In this embodiment, instead of a ferrule peninsula, there is a ferrule bridge, as now illustrated. Referring back to FIG. 26, the bridge concept for an internal ground pin is illustrated in FIG. 40 of U.S. Pat. No. 6,765,780, the contents of which are incorporated herein fully be reference.

[0206] It is noted that FIGS. 26B and 26C are only exemplary and are in no way intended to be limiting. For example, in both FIGS. 26B and 26C, instead of ground pin 111gnd electrically connected to the ferrule 112 by gold braze 150′, a gold pocket-pad may be alternatively formed in the peninsula or the bridge structure of the ferrule 112 to make the electrical connection. An electrical connection to the metallization of the via of the feedthrough capacitor 132′ (or alternatively the via of the filter capacitor may be an electrically conductive filled via) and to the gold pocket-pad (not shown) can then be made using an electrical connection material 152, which may comprise a solder, a thermal-setting conductive adhesive, an ACF film, a braze, a laser weld among others.

[0207] In the case of a solder, two commonly available solders that may be used include, but are not limited to, AG1.5, which consists of 97.5% lead, 1% tin and 1.5% silver, and SN10, comprising 10% tin, 88% lead and 2% silver. Additional solders are shown in the chart of FIG. 47, which provides exemplary non-limiting solder compositions that may be used by one skilled in the art when attaching to the ferrule pocket. Solders may alternately be in the form of a ball grid array (BGA). Ductile solders are preferable to limit thermal shock to, for example, a filter capacitor, an EMI filter circuit board, an AIMD circuit board, other AIMD circuitry, sensors, identification components, RFID chips or the like.

[0208] The thermally conductive adhesive may comprise a conductive polymer, a conductive epoxy, a conductive silicone, or a conductive polyimide, such as those manufactured by Ablestick Corporation. As use herein, the term “ACF film” is used generally to include a family of anisotropic conductive materials, which comprises an Anisotropic Conductive Adhesive (ACA), an Anisotropic Conductive Film (ACF), an Anisotropic Conductive Paste (ACP), an anisotropic conductive tape, an anisotropic conductive epoxy, and combinations thereof. The ACF film may also be in the form of an ACF film BGA.

[0209] In the case of a braze, it will be understood by those skilled in the art that the braze material used to practice the embodiment of FIG. 26B, which electrically connects an EMI filter to a hermetic feedthrough, requires low temperature braze materials (<850° C.). For example, biocompatible gold alloy braze materials, such as, but not limited to, 82Au-18In (530° C.) and 88Au-12Ge (356° C.) may be used. Gold alloy brazes comprising more than 50% gold by weight are particularly helpful when attaching filter capacitors to feedthroughs, as higher gold content (>50%) provides favorable elasticity (that is, adequate ductility) to the electrical connection, which compensates for differences in thermal expansion coefficient between the filter capacitor and the feedthrough that can fracture or even detach the filter from the feedthrough during AIMD assembly processes, for example, laser welding the ferrule of the hermetic terminal to an opening of an AIMD housing.

[0210] It is noted that solders, thermal-setting conductive adhesives, ACF films, and brazes can also be used to make connections to the ferrule that are characterized as both electrical and mechanical connections. When a connection, however, is solely mechanical (physical connections only without any need for electrical conduction), then non-electrically conductive thermal-setting adhesives, films, tapes, or low electrical conductivity solders and brazes may be used.

[0211] Further regarding brazing to a pocket-pad of a ferrule, when exposure to body fluid is negligible or unlikely (such as when the electrical connection is inside the device), other braze alloys may be used. For example, alloys that could be used include (by weight percent): CuSiI—copper/silver (28/72)—MP 780° C., indium/copper/silver (10/27/63)—MP 685-730° C., gold/nickel (82/18)—MP 950° C., nickel/gold/copper (3/35/62)—MPI000-1030° C., gold/nickel/titanium compositions including those disclosed in U.S. Pat. No. 4,938,922, the contents of which are fully incorporated herein by reference, Johnson Matthey silver-copper eutectic and pure metal brazes, Pallabraze alloys and Orobraze alloys.

[0212] The best control of braze volumes in the pocket of the ferrule is achieved by using die cut braze performs; however, a braze ring can also be made by cutting loops of wire from a wrapped coil typically provided on a mandrel. Such braze rings may require flattening and/or squeezed to close any cutting gap in the ring.

[0213] Braze preforms may also be manufactured from nano-material particles. For example, gold particle sizes less than about 5 mm allow melting temperatures of 700° C. or less depending on uniformity of size and size distribution of the particles. It is understood by one skilled in the art that the smaller the particle size, the lower the melting temperature of the braze material. It is also understood by one skilled in the art that the melting temperature of a braze material comprising nano-particles can be customized based on optimal particle size selection, mixing and preform manufacturing. For example, the melting temperature of a nanoparticle is a function of its radius of curvature, hence, large nanoparticles melt at greater temperatures due to their larger radius of curvature. One way to optimize particle size in order to customize melting temperature is to use liquid shell nucleation (LSN) modelling, which predicts that a surface layer of atoms melts prior to the bulk of a particle. The LSN model calculates melting conditions as a function of two competing order parameters using Landau potentials. One order parameter represents a solid nanoparticle, while the other represents the liquid phase. Each of the order parameters is a function of particle radius. The parabolic Landau potentials for the liquid and solid phases are calculated at a given temperature, with the lesser Landau potential assumed to be the equilibrium state at any point in the particle. In the temperature range of surface melting, the results show that the Landau curve of the ordered state is favored near the center of the particle while the Landau curve of the disordered state is smaller near the surface of the particle. The Landau curves intersect at a specific radius from the center of the particle. The distinct intersection of the potentials means that LSN predicts a sharp, unmoving interface between the solid and liquid phases at a given temperature. The exact thickness of the liquid layer at a given temperature is the equilibrium point between the competing Landau potentials. The equation below provides the condition at which an entire nanoparticle melts according to the LSN model.

[00001]$T_M\left(d\right)=\frac{4.Math.T_{\mathrm{MB}}}{H_f.Math.d}.Math.\left(\frac{{\sigma }_{\mathrm{SV}}}{1-\frac{d_0}{d}}-{\sigma }_{\mathrm{lv}}\left(1-\frac{{\rho }_s}{{\rho }_l}\right)\right),$

[0214] where: T.sub.MB=bulk melting temperature [0215] H.sub.f=bulk heat of fusion [0216] d=particle diameter [0217] d.sub.0=atomic diameter [0218] σ.sub.sv=solid-vapor interface energy [0219] σ.sub.lv=liquid-vapor interface energy [0220] ρ.sub.s=density of the solid [0221] ρ.sub.l=density of the liquid

[0222] If braze rings are made from coiled wire, it is understood by one skilled in the art that a fine gold wire is a preferable starting material, as melt temperature control is based on wire diameter and grain size. The smaller the diameter and/or grain size, the lower the melting temperature. Fine gold wire may comprise nanowires with the diameter of the nanowire on the order of a nanometer (10.sup.−9 meters), or which can alternately be defined as the ratio of the length to the width being greater than 1000. Ultra-fine wire is defined as anything below 0.002 inch (0.05 mm) in diameter. Fine wire is defined as having a diameter that ranges between 0.002 inch (0.05 mm) and 0.005 inch (0.127 mm) in diameter. Grain size is a particularly important aspect for wires used to make braze rings, as grain size can significantly affect melt temperature. For examples, studies have shown that there is a linear relation between the melting point and the reciprocal grain size of a metal with larger grain size samples, for example larger than about 7 nm, which is similar to the observations of nanoparticles. However, at a small grain size, this relation between grain size and melting temperature is broken. In particular, at grain sizes below 4 nm, the melting point is found to be approximately constant.

[0223] Brazing methods for electrical and/or mechanical connection to a ferrule may comprise: multi-stage brazing, active metal brazing, reactive brazing, transient liquid phase bonding, or other similarly suitable techniques.

[0224] FIG. 26D is taken from section 26D-26D from FIG. 26 and illustrates an active pin and an insulator 160′ that is either a fusion glass, a compression glass or a glass ceramic. In this case, there is no need for a gold braze between the ferrule and the insulator.

[0225] FIG. 27 is an electrical schematic diagram of the feedthrough capacitor filter of FIG. 26, which illustrates that the ground pin 111gnd only extends to the device side (not to the body fluid side). Active pins 111a through 111h are illustrated, each associated with its own individual feedthrough capacitor. In addition, a telemetry pin T is illustrated, which cannot be filtered. If the telemetry pin were filtered, then it would not be possible to transmit RF telemetry signals back and forth from the device.

[0226] FIG. 28 illustrates a hybrid feedthrough capacitor, which is best understood by looking at its ground electrode plates in FIG. 29 and its active electrode plates in FIG. 30. Ground electrode plate in FIG. 28, which is taken from section 29-29 from FIG. 28. This illustrates a ground electrode that is grounded to a center hole 111gnd and also at its ends, as illustrated. The ends of the capacitor ground electrodes are terminated in capacitor metallization 142. There are eight active electrodes forming eight different capacitors, as illustrated in FIG. 30. FIG. 30 is taken generally from section 30-30 from FIG. 28. The active electrodes 148 are all the same size, which would mean that all of the capacitances were of equal value. It is known to those skilled in the art to vary the active areas if different capacitance were required.

[0227] FIG. 31 illustrates a hermetic seal terminal subassembly 120 that has been prepared for mounting of the feedthrough capacitor of FIG. 28. One can see a center ground pin 111gnd, which is laser welded to gold braze 150′ to the ferrule structure 112. In addition, there are gold pockets-pads 248, 250. On the left-hand side, these are shown as two discrete pockets and on the right-hand side, this is shown as one continuous pocket. The feedthrough capacitor 132 of FIG. 28 is defined herein as a hybrid internally grounded capacitor, in that, it has both an internal ground passageway and also grounded end metallizations. Hybrid capacitors are taught by U.S. Pat. No. 6,765,780, the contents of which is fully incorporated herein with this reference. As previously noted for FIGS. 26B and 26C, the ground pin 111gnd may alternately be an oxide-resistant pocket-pad 250. All of the related structure, materials and methods disclosure also apply.

[0228] Referring back to FIG. 31, the gold pocket-pads 250 are optional, in that, if the capacitor was made shorter, an electrical contact 152 could be made to the gold braze 150 of the hermetic seal. However, as illustrated, the gold pocket pads allow the capacitor to be a little longer and extend over complex ferrule areas, including ferrule capture areas 163. These multipart pins are taught by U.S. patent Serial Nos. 15/844,683 and 15/603,521, the contents of which are incorporated herein fully be reference.

[0229] FIG. 32 illustrates the hybrid capacitor 132 of FIG. 28 mounted to the feedthrough hermetic seal subassembly 120 of FIG. 31. In accordance with the present invention and as illustrated in FIG. 32, the width of the feedthrough capacitor 268 overhangs the widest dimension of the ferrule 266. Also in accordance with the present invention, the length of the feedthrough capacitor 272 is setback (it is shorter) from the overall length or the greatest length of the ferrule 270. Accordingly, the capacitor perimeter width surfaces 252 overhang the ferrule in accordance with the present invention.

[0230] FIG. 33 is taken from section 33-33 from FIG. 32 and shows the overhanging capacitor in sectional view. FIG. 33 is taken in the y-z plane and illustrates that the capacitor sets back (does not overhang) the widest dimensions of the ferrule 112. Referring once again to FIG. 33, one can clearly see the electrical connection 152 between the internally grounded hybrid feedthrough capacitor ground metallization 142 and gold pocket-pads 250. In FIG. 33, one can also see ground pin 111gnd, which has been gold brazed 150′ into ferrule bridge 141. As previously noted for FIGS. 26B and 26C, the ground pin 111gnd may alternately be an oxide-resistant pocket-pad 250. All of the related structure, materials and methods disclosure also apply. This type of hybrid grounding, using both the end metallizations 142 and the ground pin 111gnd is very important, such that proper filter performance be maintained on every one of the active pins. This capacitor is too long to depend only on grounding by the centered pin 111gnd. Undue inductance and resistance could build up along the ground electrode plates, meaning that the furthest left and furthest right pins would have seriously degraded insertion loss (attenuation). In accordance with the hybrid concept, what results is a multi-point ground system, which means that each pin is an effective EMI filter. Hybrid internally grounded capacitors are taught by U.S. Pat. No. 6,765,780, the concepts of which are incorporated fully herein by reference.

[0231] Referring to FIG. 34, one will notice that the gold pocket-pads 248, 250 have been eliminated. In this case, the capacitor length is aligned so that an electrical connection can be made from the capacitor ground metallization 142 directly to the gold braze of the hermetic seal between the insulator 160 and ferrule 112.

[0232] FIG. 35 is a top view of the capacitor mounted onto the hermetic terminal subassembly of FIG. 34. In accordance with the present invention, one can see that the overall length 272 of the hybrid internally grounded feedthrough capacitor 132″ is shorter (has a setback) compared to the greatest overall length of the ferrule 270. Also in accordance with the present invention is the hybrid internally grounded feedthrough capacitor 132″ is wider in its width than the greatest width 266 of the ferrule 266. The greatest width 266 of the ferrule is also known as the furthermost width of the ferrule. As illustrated in FIG. 34, ferrules 112 often have irregular dimensions, so it is important that when we refer to capacitor overhang or capacitor setback, we are always referring to the greatest width or the greatest length of both an irregularly shaped ferrule and/or a regularly shaped (symmetrical) ferrule.

[0233] FIG. 36 is a cross-sectional view taken from section 36-36 from FIG. 35. This illustrates the centered ground pin 111gnd which has been gold brazed or laser welded 150′ into the ferrule peninsula structure 139. As previously noted for FIGS. 26B and 26C, the ground pin 111gnd may alternately be an oxide-resistant pocket-pad 250. All of the related structure, materials and methods disclosure also apply. The hybrid ground connections are also shown in the capacitor ground terminations 142 are shown electrically connected 152 to ferrule gold braze 150. As previously described, this multi-point grounding system assures a high level of filtering performance for each of the active pins.

[0234] FIG. 37 is a quadpolar capacitor somewhat similar to that illustrated in FIGS. 21 and 22. As illustrated, it has an overhang and also a setback in accordance with the present invention. Another distinguishing feature is revealed in FIG. 38, which is taken from section 38-38 from FIG. 37. On the left-hand side of the sectional view, one can see that the device side leadwire 111 has been segmented (complete wire segment 117). Leadwire segment 117 has been co-brazed along with body fluid side lead 114′. This is defined herein as a two-part pin. The right-hand side of FIG. 38 illustrates that the body fluid side pin 114 extends all the way through the hermetic insulator and halfway through the feedthrough capacitor. In both the left and right-hand side embodiments, there is a low-cost pin 111, which is typically of tin copper, which is co-joined and soldered approximately halfway through the feedthrough capacitor. This type of two-part or three-part pin construction greatly reduces cost because in the prior art, it was typical to take non-toxic and biocompatible leadwires, such as platinum or palladium leadwires and run them all the way through the structure. There is no need on the device side to have biocompatible materials.

[0235] Referring back to FIG. 38, on the left-hand side, we have a co-brazed pin, which is further described by U.S. Pat. No. 10,272,252, the contents of which are incorporated herein fully by reference. On the right-hand side of FIG. 41, we have a two-part pin co-joined in the feedthrough capacitor that is described by U.S. Pat. No. 10,319,859, the contents of which are also fully incorporated herein by reference.

[0236] FIG. 38A is substantially the same as FIG. 38, except in this case, the two-part lead connection is disposed inside the inside insulator passageway, as illustrated. In this case, the two-part lead 111′, 114 is joined by co-brazing the leads. Two-part pins, as illustrated in FIG. 38A, are more thoroughly described in U.S. Pat. No. 10,272,252, the contents of which are herein incorporated by reference.

[0237] FIG. 39 illustrates a cross-section of a hermetic terminal subassembly with a peninsula with a gold pocket-pad 250. It also illustrates that instead of a leadwire pin, a conductive pathway passes through the insulator. In this case, the conductive pathway consists of a ceramic reinforced metal composite material 185 with pure platinum end caps 186. Referring to FIGS. 39-45, composite reinforced metal ceramic (CRMC) co-sintered vias are more fully described in U.S. Pat. No. 10,249,415, the contents of which are incorporated herein fully be reference. CRMC vias are also described in U.S. Pat. Nos. 8,653,384; 8,938,309; 9,233,253; 9,352,150; 9,492,659; or 9,889,306, the contents of all of which are incorporated herein fully be reference. It is noted that, while FIG. 39 shows active CRMC co-sintered vias 186, 320 in the insulator 160 of the terminal feedthrough assembly 120, any of the active leadwires 111 previously shown may alternately comprise active CRMC co-sintered vias 186. Similarly, while an oxide-resistant gold pocket-pad 250 is shown in a peninsula of the ferrule 112, it is understood that the oxide-resistant gold pocket-pad 250 may reside on one of a ferrule perimeter, a ferrule edge, a ferrule peninsula, a ferrule bridge, or combinations thereof. Additionally, while the figures show attachment of EMI filters, EMI filters are only exemplary. It is anticipated that the oxide-resistant gold pocket-pad 250 of the present invention can also be used to electrically and mechanically connect an EMI filter circuit board, an AIMD circuit board, other AIMD circuitry, sensors, identification components, RFID chips or the like in addition to EMI filter capacitors to a ferrule of a hermetic terminal. Any of the above components may be overhanging the ferrule according to device design and/or application needs. Attachment structures, connection materials, and methods previously disclosed also apply.

[0238] FIG. 40 illustrates an internally grounded feedthrough capacitor 132′ of the present invention mounted to the hermetic terminal and substantially overhanging the ferrule 112. This overhang is in the x-z axis. Not shown is the sectional view from the side showing the length of the feedthrough capacitor and the length of the ferrule, but it will be appreciated that the capacitor does not overhang in the y-z axis, but it is either setback or aligned with the ferrule edge as has been previously described.

[0239] FIG. 41 is substantially the same as FIG. 40, except in this case instead of gold pockets, the ground electrical connections from the two ground pins 119gnd are directly to the hermetic seal gold braze 150 by way of 202gnd, which can be a solder, a thermal-setting conductive adhesive, ACF film or the like. Again, in accordance with the present invention, the feedthrough capacitor 132′ overhangs the ferrule in the x-z plane.

[0240] FIG. 42 is similar to FIG. 40 illustrating the present invention with an internally grounded feedthrough capacitor 132′ along with multiple connections to gold pockets 250 and 250′ In accordance with the present invention, the internally grounded feedthrough capacitor 132 overhangs the widest width of the ferrule 112 in the x-z plane.

[0241] FIG. 43 is very similar to FIGS. 41 and 42, except that in this case, ACF films are used to make the electrical connection 260 and a nail-headed ground leadwire 111gnd, as illustrated. The ACF films referred to include a family of anisotropic conductive materials, which comprise an Anisotropic Conductive Adhesive (ACA), an Anisotropic Conductive Film (ACF), an Anisotropic Conductive Paste (ACP), an anisotropic conductive tape, an anisotropic conductive epoxy, and combinations thereof. The ACF film may also be in the form of an ACF film BGA. It will be appreciated that in addition to ACF films, BGA solder bumps or BGA thermal-setting epoxy bumps could also be used. It is also appreciated that instead 202 of FIG. 40, the ACF film of FIG. 43 may be used instead. Additionally, instead of 202gnd of FIGS. 41 and 42, the ACF film of FIG. 43 may be used instead.

[0242] FIG. 44 is a close-up taken from section 44-44 from FIG. 43 illustrating compression of the ACF film conductive particles 262′ in the electrical connection area. The freely suspended particles 262 are insulated from each other providing conductivity only on the area of the nail head 111gnd nail head 260 and gold pocket area 250 of ferrule 112.

[0243] FIG. 45 is an enlarged sectional view of the gold pocket-pad 250 of FIG. 42, which resides along the perimeter of the ferrule 112. It is understood that the gold pocket-pad 250 of FIG. 45 may reside on one of a ferrule perimeter, a ferrule edge, a ferrule peninsula, a ferrule bridge, or combinations thereof. The gold pocket-pad 250 comprises an electrical connection material 202gnd, which, as previously disclosed, may comprise one of a solder, a thermal-setting conductive adhesive, an ACF film, among others.

[0244] FIGS. 46A and 46B are sectional views of embodiments of a ferrule 112, wherein the ferrule comprises a recessed pocket 248, the recessed pocket 248 comprising a pocket-pad 250 nested therein. It is appreciated (but not shown) that the pocket-pad 250 may be mechanically and/or electrically connected to the recessed ferrule pocket 248 by one of a solder, a thermal-setting conductive adhesive, an ACF film, or a braze, a laser weld or the like. The solders, thermal-setting conductive adhesives, ACF films, and brazes previously disclosed for FIGS. 26B and 26C apply to FIGS. 46A and 46B. Optionally, the pocket-pad 250 may be partially proud of the ferrule surface, particularly when needed for compression of ACF film conductive particles or spheres.

[0245] FIGS. 46A and 46B show that the pocket-pad 250 is formed on a perimeter or an edge of the ferrule 112; however, it is understood that the pocket-pad 250 may also be formed on a peninsula or a bridge of a ferrule as previously disclosed. FIG. 46A shows a pocket-pad 250 on the ferrule device side while FIG. 46B shows a pocket-pad 250 on the ferrule body fluid side. The pocket-pad 250 of FIGS. 46A and 46B further comprises a connection material 200, 202gnd, which, as previously disclosed, may comprise one of a solder, a thermal-setting conductive adhesive, an ACF film, among others. The connection material 202, 202gnd may be used to make either a mechanical connection or an electrical connection to the ferrule 112. The electrical connection to the ferrule 112 may further be a ground electrical connection to a circuit of an AIMD, such as, but not limited to, an AIMD circuit board or an EMI filter circuit board. The ground electrical connection may further be internal to the AIMD, such as to an EMI filter capacitor, an EMI filter circuit board, an AIMD circuit board, other AIMD circuitry, sensors, identification components or devices, RFID chips, and the like. The ground electrical connection may alternatively be external to the AIMD, such as to a header block, a sensor, an identification component or device, an RFID chip, a telemetry antenna, and the like. As previously disclosed, the pocket-pad 250 may comprise a connection material 202, 202gnd, the connection material 202, 202gnd comprising one of gold, platinum, palladium, silver, iridium, rhenium, rhodium, tantalum, titanium, tungsten, niobium, zirconium, vanadium, and alloys or combinations thereof. The connection material 202, 202gnd may alternatively comprise titanium alloys, for example, but not limited to, titanium-aluminum-vanadium, titanium-platinum, titanium-niobium, titanium-gold, among others. The connection material may further comprise an oxide-resistant material. The oxide-resistant material may comprise gold alloys, for example but not limited to, gold-platinum, gold-palladium, gold-iridium, gold-silver, gold-niobium, gold-rhenium, gold-rhodium, gold-titanium, among others. The oxide-resistant material may alternatively comprise platinum alloys, for example, but not limited to platinum-iridium, platinum-gold, platinum-silver, platinum-niobium, platinum-rhenium, platinum rhodium, among others. The oxide-resistant material may alternatively comprise palladium alloys, for example, but not limited to palladium-platinum, palladium-iridium, palladium-gold, palladium-silver, palladium-niobium, palladium-rhenium, palladium-rhodium, among others. It is understood that any of the connection materials may be used on the device side of the AIMD; however, only oxide-resistant, biocompatible and non-toxic connection materials may be used on the body fluid side of the AIMD.

[0246] FIG. 46C illustrates a feedthrough comprising a rectangular-shaped ferrule 112 with a recessed perimeter pocket 248 and pocket-pad 250 disposed therein. The cross-sectional view C-C of FIG. 46C shows the height h of the ferrule, which extends to a ferrule first side end surface and a ferrule second side end surface. The cross-sectional view C-C also shows the depth d of the recessed pocket 248, which extends from a ferrule first side end surface toward the ferrule second side end surface, or from the ferrule second side end surface toward the ferrule first side end surface. While a full perimeter pocket 248 and pocket-pad 150 is illustrated (the at least one recessed pocket is a continuous recessed pocket surrounding the ferrule opening and the oxide-resistant pocket-pad is nested in the continuous recessed pocket), it is understood by one skilled in the art that the recessed pocket 248 and pocket-pad 150 may be discontinuous or a partial pocket 248 and associated pocket-pad 150. A partial pocket 248 and pocket-pad 150 may, for example, be provided on one or more edges of a rectangular or square ferrule or may be provided as a semicircle or an arc perimeter pocket-pad on a discoidal ferrule.

[0247] FIG. 46D illustrates a feedthrough comprising a discoidal-shaped ferrule 112 with three recessed pockets 248 and associated pocket-pads 150 at circumferentially spaced locations one from another, thereby providing 360° of connectability to the ferrule. Such a 360° circumferential configuration also provides selective connectability options to the ferrule. Connections can be made to one, two or all three pocket-pads. Each connection may be to a single component of the AIMD, or, alternatively, a different component of the AIMD may be connected to each pocket-pad provided on the ferrule. For example, one pocket pad 250 may be connected to an EMI filter capacitor, a second pocket-pad 250 may be connected to a circuit board and a third pocket-pad 250 may be connected to an RFID chip. It is understood by one skilled in the art that, while the pocket-pads 250 of FIG. 47 are shown on the first side of the ferrule of the feedthrough, one or more pocket-pads may also be provided on the second side of the ferrule of the feedthrough. It is also understood by one skilled in the art that a plurality or ‘n’ number of recessed pockets 248 and associated pocket-pads 150 may be provided at spaced locations about the ferrule opening on one of the first side, the second side or both the first and second sides of the ferrule.

[0248] The cross-sectional view D-D of FIG. 46D illustrates that the recessed pocket 248 of the pocket-pads 250 may be configured differently. The cross-sectional view D-D also shows that the pocket-pad 250 may be partially proud of a ferrule side end surface. Two non-limiting examples are shown on the right and left sides of the cross-section of FIG. 46D. The left side pocket 248 has a rectangular-shape in cross-section with 90° corners and the right-side pocket is a cup-shaped semi-circular pocket 248. Any pocket shape may be provided to facilitate connection, including lock and key type configurations. The cross-sectional view D-D of FIG. 46D also shows the height h of the ferrule, which extends to a ferrule first side end surface and a ferrule second side end surface. The cross-sectional view D-D also shows the depth d of the recessed pocket 248, which extends from a ferrule first side end surface toward a ferrule second side end surface, or from the ferrule second side end surface toward the ferrule first side end surface.

[0249] FIG. 47 is a chart of various solder materials that may be used to make attachments to any of the ferrule 112 pocket-pad 250 embodiments disclosed herein. The solder compositions listed in the chart of MG. 47 reflect element weight percents, are exemplary only and are not meant to be limiting.

[0250] Although several embodiments of the invention have been described in detail, for purposes of illustration, various modifications of each may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited, except as by the appended claims.