M7 LTCC-Silver System And Related Dielectric Compositions For High Frequency Applications

Abstract

LTCC devices are produced from dielectric compositions include a mixture of precursor materials that, upon firing, forms a dielectric material having a magnesium-silicon oxide host. An associated Ag system for LTCC conductors is also described.

Claims

1: A composition comprising: (a) 85-95 wt % of a calcined host comprising: 1. 49-65 wt % MgO, 2. 35-51 wt % SiO.sub.2, and 3. is free of at least any one of the following in any form: lead, cadmium, zinc, manganese, bismuth, titanium, arsenic, and mercury, and (b) additives comprising: 1. 2.5-6 wt % H.sub.3BO.sub.3, 2. 0.01-0.1 wt % CuO 3. 0.5-3 wt % of at least one alkali fluoride, and 4. 3-7 wt % of at least one alkaline-earth fluoride, and (c) is free of at least any one of the following in any form: lead, cadmium, zinc, manganese, bismuth, titanium, arsenic, and mercury, and (d) wherein the sum of (a) and (b) is 100 weight percent.

2: The composition of claim 1, wherein (a) the calcined host comprises 1. 53-61 wt % MgO, 2. 39-47 wt % SiO.sub.2, and 3. is free of at least any one of none of the following in any form: lead, cadmium, zinc, manganese, bismuth, titanium, arsenic, and mercury, and (b) the additives include 1. 3-5 wt % H.sub.3BO.sub.3, 2. 0.05-0.5 wt % CuO 3. 0.8-1.9 wt % of at least one alkali fluoride, and 4. 3.8-5.4 wt % of at least one alkaline-earth fluoride.

3: The composition of claim 1 or 2, wherein (a) the calcined host comprises 1. 56-59 wt % MgO, 2. 41-44 wt % SiO.sub.2, and 3. is free of at least any one of the following in any form: lead, cadmium, zinc, manganese, bismuth, titanium, arsenic, and mercury, and (b) the additives include 1. 3.3-4.5 wt % H.sub.3BO.sub.3, 2. 0.1-0.3 wt % CuO 3. 1-1.6 wt % of at least one alkali fluoride, and 4. 4-5.1 wt % of at least one alkaline-earth fluoride.

4: The composition of any of claims 1-3 wherein the composition includes 87-92 wt % of the calcined host.

5: The composition of any of claims 1-3 wherein the composition includes 88-91 wt % of the calcined host.

6: The composition of any of claims 1-5, wherein the at least one alkali fluoride comprises lithium fluoride, and the at least one alkaline-earth fluoride comprises calcium fluoride.

7: The composition of any of claims 1-6, wherein the composition is free of all of the following in any form: lead, cadmium, zinc, manganese, bismuth, titanium, arsenic, and mercury.

8: A slip for forming a dielectric tape or paste comprising: (a) 49.13-56.87 wt % of a dielectric powder comprising the composition of any of claims 1 to 7, (b) 2.62-3.61 wt % of a plasticizer comprising trimethylene glycol bis (2-ethylhexanoate), and (c) 33.46-38.12 wt % of at least one solvent selected from the group consisting of ethanol, xylene, and methyl ethyl ketone, and (d) 6.45-8.85 wt % resin comprising polyvinyl butyral, and (e) wherein the sum of (a)-(d) is 100 weight percent.

9: The slip of claim 8, wherein the at least one solvent comprises all of ethanol, xylene, and methyl ethyl ketone.

10: A silver paste comprising: (a) 11.5-13.2 wt % first silver flake having a particle size D.sub.50 in the range of 0.6-0.8 μm, (b) 11.5-13.2 wt % first silver powder having a D.sub.50 in the range of 3-5 μm, (c) 37-43 wt % second silver powder having a D.sub.50 in the range of 0.7-2 μm, (d) 3-6 wt % dielectric powder, wherein the dielectric powder comprises the composition of any of claims 1 to 7, (e) 2-4.5 wt % glass frit, and (f) 25.1-36.4 wt % organic vehicle, and (g) wherein the sum of (a)-(f) is 100 weight percent.

11: A silver paste comprising: (a) 12.39 wt % first silver flake, (b) 12.39 wt % first silver powder, (c) 40.26 wt % second silver powder, (d) 1.43 wt % dielectric powder, (e) 6.80 wt % glass frit, and (f) 26.73 wt % organic vehicle, and (g) wherein the sum of (a)-(f) is 100 weight percent.

12: A silver paste comprising: (a) 40-50 wt % second silver powder having a D.sub.50 in the range of 0.7-2 μm, (b) 23-25 wt % third silver powder having a D.sub.50 in the range of 0.2-5 μm, (c) 7-11 wt % dielectric powder, wherein the dielectric powder comprises the composition of any of claims 1 to 7, and (d) 23.7-29.8 wt % organic vehicle, and (e) wherein the sum of (a)-(d) is 100 weight percent.

13: A silver paste comprising: (a) 42-47 wt % second silver powder having a D.sub.50 in the range of 0.7-2 μm, (b) 23.5-24.5 wt % third silver powder having a D.sub.50 in the range of 0.2-5 μm, (c) 1-3 wt % dielectric powder, wherein the dielectric powder comprises the composition of any of claims 1 to 7, (d) 6-9 wt % glass frit, and (e) 23.8-29.7 wt % organic vehicle, and (f) wherein the sum of (a)-(e) is 100 weight percent.

14: A silver paste comprising: (a) 21.5-28.5 wt % fourth silver powder having an average particle size in the range of 1.5-3.5 μm, (b) 37.1-41.9 wt % fifth silver powder having an average particle size in the range of 2.5-4 μm, (c) 1.31-4.5 wt % borosilicate glass frit, (d) 11.94-23.25 wt % organic vehicle, and (e) 13.5-17.5 wt % cordierite powder, and (f) wherein the sum of (a)-(e) is 100 weight percent.

15: A silver paste comprising: (a) 24.79-25.18 wt % fourth silver powder, (b) 41.21-41.86 wt % fifth silver powder, (c) 1.48-2.18 wt % borosilicate glass frit, (d) 17.44-18.73 wt % organic vehicle, and (e) 13.10-14.05 wt % quartz powder, and (f) wherein the sum of (a)-(e) is 100 weight percent.

16: An LTCC component comprising a sintered plurality of alternating layers of (a) a composition of any of claims 1-7, and (b) a conductor of any of claims 10-15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0028] LTCC (Low Temperature Co-fired Ceramic), is a multi-layer, glass ceramic substrate technology which is co-fired with low resistance metal conductors, such as Ag, Au, Pt or Pd, or combinations thereof, at relatively low firing temperatures (less than 1000° C.). Sometimes it is referred to as “Glass Ceramics” because its main composition may consist of glass and alumina or other ceramic fillers. Some LTCC formulations are recrystallizing glasses. Glasses herein may be provided in the form of frits which may be formed in situ or added to a composition.

[0029] A tape cast from a slurry of dielectric material is cut, and holes known as vias are formed to enable electrical connection between layers. The vias are filled with a conductive paste, such as any silver paste disclosed herein. Circuit patterns are then printed, along with co-fired resistors as needed. Multiple layers of printed substrates are stacked. Heat and pressure are applied to the stack to bond layers together. Low temperature (<1000° C., or <900° C.) sintering is then performed. The sintered stacks are sawn to final dimensions and post fire processing completed as needed.

[0030] Multilayer structures useful in automotive applications may have about 5 ceramic layers, for example 3-7 or 4-6. In RF applications, a structure may have 10-25 ceramic layers. As a wiring substrate, 5-8 ceramic layers may be used.

[0031] Dielectric Pastes. A paste for forming the dielectric layers can be obtained by mixing an organic vehicle with a raw dielectric material, as disclosed herein. Also useful are precursor compounds (e.g. carbonates, nitrates, sulfates, phosphates) that convert to such oxides and composite oxides upon firing, as stated hereinabove. The dielectric material is obtained by selecting compounds containing these oxides, or precursors of these oxides, and mixing them in the appropriate proportions. The proportion of such compounds in the raw dielectric material is determined such that after firing, the desired dielectric layer composition may be obtained. The raw dielectric material (as disclosed elsewhere herein) is generally used in powder form having a mean particle size of about 0.1 to about 3 microns, and more preferably about 1 micron or less.

[0032] Organic Vehicle. The pastes herein include an organics portion. The organics portion is or includes an organic vehicle, which is a binder in an organic solvent or a binder in water. The binder is chosen to afford desired green strength or other desired properties of the green paste or tape. Binders such as ethyl cellulose, polyvinyl butanol, ethyl cellulose, and hydroxypropyl cellulose, and combinations thereof are appropriate together with a solvent. A resin such as an acrylic resin may be used in the vehicle. The organic solvent may be selected in accordance with a particular application method (i.e., tape casting, printing or sheeting), from organic solvents such as ester alcohols, for example tripropylene glycol n-butyl ether and dipropylene glycol dibenzoate, butyl carbitol, other solvents such as acetone, toluene, ethanol, diethylene glycol butyl ether; 2,2,4-trimethyl pentanediol monoisobutyrate (Texanol®); alpha-terpineol; beta-terpineol; gamma terpineol; tridecyl alcohol; diethylene glycol ethyl ether (Carbitol®), diethylene glycol butyl ether (Butyl Carbitol®) and propylene glycol; and blends thereof, Products sold under the Texanol® trademark are available from Eastman Chemical Company, Kingsport, Tenn.; those sold under the Dowanol® and Carbitol® trademarks are available from Dow Chemical Co., Midland, Mich. A rheological agent (thixotropic agent) may be included such as castor or its hydrogenated derivatives. The organics of the invention are Phthalate free.

[0033] Filler. In order to minimize expansion mismatch between tape layers of differing dielectric compositions, fillers such as cordierite, alumina, zircon, fused silica, aluminosilicates and combinations thereof may be added to one or more dielectric pastes herein in an amount of 1-30 wt %, preferably 2-20 wt % and more preferably 2-15 wt %.

[0034] Firing. The dielectric stack (two or more layers) is then fired in an atmosphere, which is determined according to the type of conductor in the internal electrode layer-forming paste. The conductors contemplated herein include silver, a noble metal, hence the conductors herein may be fired in the ambient atmosphere.

[0035] Applications for the LTCC compositions and devices disclosed herein include band pass filters, (high pass or low pass), wireless transmitters and receivers for telecommunications including cellular applications, power amplifier modules (PAM), RF front end modules (FEM), WiMAX2 modules, LTE-advanced modules, transmission control units (TCU), electronic power steering (EPS), engine management systems (EMS), various sensor modules, radar modules, pressure sensors, camera modules, small outline tuner modules, thin profile modules for devices and components, and IC tester boards. Band-pass filters contain two major parts, one a capacitor and the other an inductor. Low K material is good for designing the inductor, but not suitable for designing a capacitor due the requirement for more active area to generate sufficient capacitance. High K material will result in the opposite.

EXAMPLES

[0036] The following examples are provided to illustrate preferred aspects of the invention and are not intended to limit the scope of the invention.

[0037] As seen in the Table 2 below, appropriate amounts of Mg(OH).sub.2, and SiO.sub.2, are mixed and then milled together in an aqueous medium to a particle size D.sub.50 of about 0.2 to 1.5 μm. This slurry is dried, and then calcined at about 800 to 1250° C. for about 1 to 10 hours to form the host material including MgO and SiO.sub.2. The resultant host material is then mechanically pulverized and mixed with fluxing agents and dopants (see Table 3) and again milled in an aqueous medium to a particle size D.sub.50 of about 0.5 to 1.0 μm. The milled ceramic powder is dried and pulverized to produce a finely divided powder. The resultant powder is pressed into cylindrical pellets and fired at a temperature range of about 825-880° C. for about 30 minutes. Formulations are given in weight percent.

TABLE-US-00002 TABLE 2 Embodiments of the M7 Host composition in weight % Oxide I II III IV MgO 49-65 53-61 56-59 57.295 SiO.sub.2 37-51 39-47 41-44 42.705

TABLE-US-00003 TABLE 3 M7 Dielectric Formulations in weight % Host 85-95 87-92 88-91 H.sub.3BO.sub.3 2.5-6 3-5 3.3-4.5 CuO 0.01-1  0.05-0.5  0.1-0.3 LiF 0.5-3 0.8-1.9 .sup. 1-1.6 CaF.sub.2 .sup. 3-7 3.8-5.4 4.4-5.1

[0038] The 825° C. fired properties of the M7 LTCC dielectric are summarized in Table 4. The green tape is made by combining the M7 dielectric powder (as disclosed in Tables 2 and 3) pulverized and milled to a particle size D.sub.50 of about 0.5 to 1.0 μm with dispersant, binder, plasticizer and solvents, milling to form a castable slip, casting the slip onto a mylar carrier film and drying it to form a flexible, punch-able ceramic green tape, 50 to 125 microns thick.

TABLE-US-00004 TABLE 4 M7 LTCC Dielectric 825° C. Fired Properties Property Value Green Tape Thickness (μm)  50-125 XY shrink (green-to-fired)    .sup. 16.86% Z shrink (green-to-fired)    .sup. 26.86% Flexural Strength (Mpa) 294 Fired Density (g/cc)    3.12 Coefficient of Thermal Expansion (ppm/° K.)  .sup. 10.9 K at 15.83 GHz    7.07 Q at 15.83 GHz 1631  Loss Tangent at 15.83 GHz     0.0006 IR (ohm) @ 50 V DC bias, Room Temperature .sup. >10.sup.13 Breakdown Voltage (V/micron) 167 Thermal Conductivity (W/mK) RT-200° C. 4-5
Green tape slip formulations are shown in Table 5. Via holes with a diameter in the range of 0.15-0.51 mm are punched into the ceramic green tape and then filled with Ag paste to enable electrical connections between the ceramic layers. The conductors (surface, buried and via) are screen or stencil printed on the green tape and multiple printed layers are laminated together at 3000 psi/70° C./10 min to form multilayer parts which are fired at 825-850° C. to densify the ceramic tape and Ag conductors.

TABLE-US-00005 TABLE 5 M7 Dielectric Slip Formulations Material weight % (total = 100%) A B C M7 Powder 50.64-56.32 49.13-56.87 51.89-54.95 Polyvinyl Butyral 6.79-8.44 6.45-8.85 6.92-8.00 Resin Triethylene Glycol Bis 2.70-3.47 2.62-3.61 2.81-3.35 (2-ethylhexanoate) Ethanol 11.41-12.52 11.05-12.75 11.75-12.25 Xylene 11.23-12.38 10.98-12.46 11.71-12.29 Methyl Ethyl Ketone 11.59-12.67 11.43-12.91 11.65-12.43
Thick film Ag conductor pastes compatible with the green tape and cofirable at 825-850° C. were also developed. The properties of the cofired Ag conductors are summarized in Table 6. The surface Ag conductor is designed to be electroless Ni and Au platable.

TABLE-US-00006 TABLE 6 M7 LTCC Ag Conductors Ag Paste Product Surface Internal Via Name Formula 1 Formula 3 Formula 5 Fired thickness (μm) 5-10 5-10 0.15-0.51 mm diameter Resistivity  0.80  1.1 (mΩ/sq@ 25 μm) Viscosity Pa .Math. S 219.7 @2.5 rpm 131.2 @5 rpm 47 @5 rpm (Brookfield 2HB, CP51; down curve) Solids Wt % 73.12 73.3 81.3-82.6    

[0039] The formulations for the Ag conductor pastes (surface, buried and via) for which properties are shown in the Table 6 above are presented in Tables 7-9. The Ag conductors are made by mixing together Ag powder(s) with filler materials (ceramic and/or glass), organic vehicle, dispersant and solvent and then 3-roll milling to form a thick film paste which is screen printed onto to the ceramic green tape and then dried at 125° C. EG2807 glass powder and L8 VWG glass powders are commercially available from Ferro Corporation, Cleveland, Ohio.

Multilayer parts are made by stacking and isostatically laminating Ag-printed green tape layers and then firing in air at 825-850° C.

TABLE-US-00007 TABLE 7 Surface Ag Paste Compositions Material in weight % Formula 1 Formula 2 M7 Dielectric Powder 3.35 1.43 EG2807 Glass Powder 4.02 -0- L8 VWG Powder -0- 6.80 Ag Flake 1; D.sub.50 0.6-0.8 μm 12.51 12.39 Ag Powder 1; D.sub.50 3.0-5.0 μm 12.51 12.39 Ag Powder 2; D.sub.50 0.7-2.0 μm 40.72 40.26 GGS-20 Vehicle 22.54 21.85 Ester Alcohol 4.05 4.57 Oleoyl Sarcosine 0.29 0.31 Total 100.00% 100.00%

TABLE-US-00008 TABLE 8 Inner Layer Ag Formulations Material in weight % Formula 3 Formula 4 Formula X Formula Y Formula Z Ag Powder 2; D.sub.50 0.7-2.0 μm 40.53 40.63 40-50 42-47 42-47 Ag Powder 3; D.sub.50 0.2-0.5 μm 23.94 24.01 23-25 23.5-24.5 23.5-24.5 M7 Dielectric Powder 8.81 1.43  7-11  8-10 1-3 L8 VWG Powder -0- 7.40 -0- -0- 6-9 GGS-20 Vehicle 22.04 22.10 20-24 21-23 20-24 Oleoyl Sarcosine 0.48 0.48 0.2-0.8 0.3-0.7 0.3-0.7 Ester Alcohol 4.20 3.95 3.5-5   3.2-4.5 3.5-5   Total 100.00% 100.00% 100.00% 100.00% 100.00%

TABLE-US-00009 TABLE 9 Via Ag Paste Composition Material in weight % Formula 5 Ag Powder 4; Avg P.S. 1.5-3.5 μm 24.79-25.18 Ag Powder 5; Avg P.S. 2.5-4.0 μm 41.21-41.86 Fused Quartz Powder 13.10-14.05 Borosilicate Glass Powder 1.48-2.18 Oleoyl Sarcosine 0.31 Vehicle 150 INT 17.13-18.42

[0040] Organic Vehicles with which the pastes or tapes of the invention are produced are shown in Tables 10 and 11.

TABLE-US-00010 TABLE 10 GGS-20 Vehicle Composition Material Weight % Ethyl Cellulose Resin 19.4 Acrylic Resin 1.6 Ester Alcohol 79.0 Total 100.0%

TABLE-US-00011 TABLE 11 Vehicle 150 INT Composition Material Weight % Monoterpene Alcohol 44.10 Triprpopylene Glycol n-Butyl Ether 11.03 Dipropylene Glycol Dibenzoate 33.07 Ethyl Cellulose Resin 9.80 Castor Oil Derivative 2.00 Total 100%

[0041] In another embodiment, as shown in Table 12, a surface Ag conductor paste may include 11.5-13.2 wt % first silver flake, 11.5-13.2 wt % first silver powder, and 37-43 wt % second silver powder. The surface Ag conductor may further include 3-6 wt % dielectric powder, and 2-4.5 wt % EG 2807 glass powder (commercially available; from Ferro Corporation, Cleveland, Ohio). In yet another embodiment, a surface Ag conductor may include 11.5-13.2 wt % first silver flake, 11.5-13.2 wt % first silver powder, and 37-43 wt % second silver powder, 2.5-5.5 wt % dielectric powder, and 2.5-4.5 wt % EG 2807 glass powder. In still another embodiment, a surface Ag conductor paste may include 11.7-13.0 wt % first silver flake, 11.7-13.0 wt % first silver powder, and 38-42 wt % second silver powder. The surface Ag conductor may further include 3.0-5.0 wt %, preferably 3.5-5.0 wt % dielectric powder, and 2.5-4.0 wt %, preferably 2.6-3.8 wt % EG 2807 glass powder. The first silver flake, first silver powder, and second silver powder may have any combination of D.sub.50 (or average particle size) set forth elsewhere herein.

TABLE-US-00012 TABLE 12 Surface Ag Paste Compositions Material in weight % Formula 13 M7 Dielectric Powder 3-6 EG2807 Glass Powder .sup. 2-4.5 Ag Flake 1 11.5-13.2 Ag Powder 1 11.5-13.2 Ag Powder 2 37-43 GGS-20 Vehicle 21-31 Ester Alcohol 4-5 Oleoyl Sarcosine 0.1-0.4 Total 100%

[0042] The ranges for components of via Ag conductors are shown in Table 13. A via Ag conductor paste may include 21.5-28.5 wt %, preferably 23-25 wt % fourth silver powder and 37.1-40.9 wt %, preferably 38-40 wt % fifth silver powder. A via Ag conductor may further include a 13.5-17.5, preferably 14.5-17 w % dielectric powder. A via Ag conductor paste further may include 1.31-4.5 wt %, preferably 2-4.5 wt % of at least one of EG0024 glass powder, EG2810 glass powder, and EGO912 glass powder (Ca-Borosilicate Glass with Softening Point 650-750° C.). The foregoing EG0024 and EG2810 glass powders are commercially available from Ferro Corporation, Cleveland, Ohio.

TABLE-US-00013 TABLE 13 Via Ag Paste Composition Material in weight % Formula V2 Ag Powder 4 21.5-28.5 Ag Powder 5 37.1-41.9 Cordierite Powder 13.5-17.5 EG0024 Glass Powder or EG2810 Glass 1.31-4.50 Powder or EG0912 Glass Powder Oleoyl Sarcosine 0.34-0.7  Vehicle 150 INT 11.5-14.8 Other additives  0.1-7.75 Total 100 wt %

[0043] In one embodiment, the D.sub.50 for Ag Flake 1 is within the range 0.1-1.5 μm, preferably 0.1-1.1 μm, more preferably 0.4-0.9 μm, and most preferably 0.6-0.8 μm. The D.sub.50 for Ag Powder 1 is within the range 2.1-8 μm, preferably 2.3-7 μm, more preferably 2.6-6 μm, and most preferably 3-5 μm. The D.sub.50 for Ag Powder 2 is within the range 0.4-3 μm, preferably 0.5-2.8 μm, more preferably 0.6-2.5 μm, and most preferably 0.7-2 μm. The D.sub.50 for Ag Powder 3 is within the range 0.05-0.8 μm, preferably 0.05-0.6 μm, more preferably 0.1-0.55 μm, and most preferably 0.2-0.5 μm. An average particle size for Ag Powder 4 is within the range 0.7-5 μm, preferably 0.8-4 μm, more preferably 1-3.8 μm, and most preferably 1.5-3.5 μm. An average particle size for Ag Powder 5 is within the range 1.5-6 μm, preferably 1.7-5 μm, more preferably 2-4.5 μm, and most preferably 2.5-4 μm.

[0044] The invention is further defined by the following items. [0045] Item 1: A composition comprising: [0046] (a) 85-95 wt % of a calcined host comprising: [0047] 1. 49-65 wt % MgO, [0048] 2. 35-51 wt % SiO.sub.2, and [0049] 3. none of the following in any form: lead, cadmium, zinc, manganese, bismuth, titanium, arsenic, and mercury, and [0050] (b) additives comprising: [0051] 1. 2.5-6 wt % H.sub.3BO.sub.3, [0052] 2. 0.01-0.1 wt % CuO [0053] 3. 0.5-3 wt % of at least one alkali fluoride, and [0054] 4. 3-7 wt % of at least one alkaline-earth fluoride, and [0055] (c) none of the following in any form: lead, cadmium, zinc, manganese, bismuth, titanium, arsenic, and mercury, and [0056] (d) wherein the sum of (a) and (b) is 100 weight percent. [0057] Item 2: The composition of item 1, wherein [0058] (a) the calcined host comprises [0059] 1. 53-61 wt % MgO, [0060] 2. 39-47 wt % SiO.sub.2, and [0061] 3. none of the following in any form: lead, cadmium, zinc, manganese, bismuth, titanium, arsenic, and mercury, and [0062] (b) the additives include [0063] 1. 3-5 wt % H.sub.3BO.sub.3, [0064] 2. 0.05-0.5 wt % CuO [0065] 3. 0.8-1.9 wt % of at least one alkali fluoride, and [0066] 4. 3.8-5.4 wt % of at least one alkaline-earth fluoride. [0067] Item 3: The powder composition of any of items 1 or 2, wherein [0068] (a) the calcined host comprises [0069] 1. 56-59 wt % MgO, [0070] 2. 41-44 wt % SiO.sub.2, and [0071] 3. none of the following in any form: lead, cadmium, zinc, manganese, bismuth, titanium, arsenic, and mercury, and [0072] (b) the additives include [0073] 1. 3.3-4.5 wt % H.sub.3BO.sub.3, [0074] 2. 0.1-0.3 wt % CuO [0075] 3. 1-1.6 wt % of at least one alkali fluoride, and [0076] 4. 4.4-5.1 wt % of at least one alkaline-earth fluoride. [0077] Item 4: The powder composition of any of items 1-3 wherein the composition includes 87-92 wt % of the host. [0078] Item 5: The powder composition of any of items 1-3 wherein the composition includes 88-91 wt % of the host. [0079] Item 6: A slip for forming a dielectric tape or paste comprising: [0080] (a) 50-60 wt % of a dielectric powder, [0081] (b) 5-10 wt % of a plasticizer, [0082] (c) 30-45 wt % of at least one solvent. [0083] Item 7: A silver paste comprising: [0084] (a) a first silver flake having a particle size D.sub.50 of 0.6-0.8 μm, [0085] (b) a first silver powder having a D.sub.50 of 3-5 μm, [0086] (c) a second silver powder having a D.sub.50 of 0.7-2 μm, [0087] (d) a dielectric powder, [0088] (e) an optional glass frit, and [0089] (f) an organic component. [0090] Item 8: A silver paste comprising: [0091] (a) a second silver powder having a D.sub.50 of 0.7-2 μm, [0092] (b) a third silver powder having a D.sub.50 of 0.2-5 μm, [0093] (c) a dielectric powder, [0094] (d) an optional glass frit, and [0095] (e) an organic component. [0096] Item 9: A silver paste comprising: [0097] (a) a fourth silver powder having an average particle size of 1.5-3.5 μm, [0098] (b) a fifth silver powder having an average particle size of 2.5-4 μm, [0099] (c) a dielectric powder, [0100] (d) an optional glass frit, and [0101] (e) an organic component. [0102] Item 10: An LTCC component comprising: sintered plurality of alternating layers of [0103] (a) a composition of any of items 1-5 with [0104] (b) a conductor of any of items 7-9.

[0105] Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and illustrative examples shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.