METHOD FOR INTEGRATING AT LEAST ONE 3D INTERCONNECTION FOR THE MANUFACTURE OF AN INTEGRATED CIRCUIT
20180254258 ยท 2018-09-06
Assignee
Inventors
Cpc classification
H01L2224/24991
ELECTRICITY
H01L2224/24226
ELECTRICITY
H05K3/4661
ELECTRICITY
H05K3/4661
ELECTRICITY
H01L2924/19104
ELECTRICITY
H01L24/82
ELECTRICITY
H01L2224/24051
ELECTRICITY
International classification
Abstract
The invention relates to a method for integrating at least one interconnection for the manufacture of an integrated circuit, including a step of depositing at least one insulating body onto a substrate including a horizontal surface, said insulating body comprising a first wall extending from the horizontal surface of the substrate to a high point of said insulating body and a step of depositing a one-piece electrical structure which is made of an electrically conductive material and extends on the horizontal surface of the substrate and the first wall of the insulating body, the first wall being vertically angled by more than 10 m and having a rising slope extending from the horizontal surface of the substrate to the high point of said insulating body.
Claims
1. Method for integrating at least one interconnection for the manufacture of an integrated circuit comprising: step of depositing at least one insulating body onto a substrate comprising a horizontal surface, said insulating body comprising a first wall extending from the horizontal surface of the substrate to a high point of said insulating body, a step of depositing a one-piece electrical structure made of an electrically conductive material extending on the horizontal surface of the substrate and the first wall of the insulating body in such a way as to form an interconnection, and wherein the first wall is vertically angled and has a rising slope from the horizontal surface of the substrate to the high point of said insulating body, the first wall comprising a horizontal component and a vertical component greater than 10 m, the ratio of inclination of the horizontal component over the vertical component is between 0.001 and 1.35.
2. Method according to claim 1, wherein the ratio of inclination of the horizontal component over the vertical component is between 0.01 and 1.
3. Method according to claim 1, wherein the first wall is vertically angled and has a rising slope from the horizontal surface of the substrate to the high point of said insulating body, with the first wall comprising a horizontal component and a vertical component greater than 10 m, the ratio of inclination of the horizontal component over the vertical component is between 0.001 and 1.35, the insulating body comprising a body comprised of conductor and/or semi-conductor and/or magnetic and/or dielectric material, having a vertical wall or with undercuts, which is covered with an insulating layer, the insulating layer covering the vertical wall or with undercuts making it possible to obtain the inclination of the first wall of the insulating body, the method comprises: a step of making openings in the insulating layer, a step of depositing a one-piece electrical structure made of an electrically conductive material extending on the horizontal surface of the substrate and the first wall of the insulating body in such a way as to form an interconnection with the body comprised of conductor and/or semi-conductor and/or magnetic and/or dielectric material via said openings.
4. Method according to claim 3, wherein, with the insulating layer being photosensitive, the method comprises a step of insulating the insulating layer through a mask in such a way as to precisely control the inclination of the first wall of the insulating body.
5. Method according to claim 4, wherein the mask comprises a zone, configured to insulate the first wall from the insulating body, which comprises a plurality of patterns of variable lengths and widths in such a way as to control the inclination thereof.
6. Method according to claim 5, wherein said zone comprises a plurality of patterns of which the width is decreasing along an axis directed from the top of the first wall of the insulating body downwards.
7. Method according to claim 4, wherein the mask comprises a plurality of different zones in such a way as to individually control the inclination of several first walls.
8. Method according to claim 5, wherein the patterns are positioned parallel to the slope of the first wall of the insulating body in such a way as to create a determined insulation at a predetermined slope height.
9. Method according to claim 4, wherein the openings in the insulating layer are carried out during the step of insulating.
10. Method according to claim 3, comprising a step of depositing a layer of resin onto the insulating layer in such a way as to form a mould that limits the extension of the electrically conductive material during the step of depositing the electrical structure.
11. Method according to claim 10, wherein said mould has a thickness between 10 and 150 m and has a width/thickness resolution between 1 for 0.5 and 1 for 50, preferably, between 1 for 2 and 1 for 25.
12. Method according to claim 10, wherein, the substrate comprising a cavity wherein is positioned the insulating body, said mould extends at least partially into said cavity adjacently to said insulating body.
13. Method according to claim 1, wherein the horizontal component is between 0.1 and 150 m, preferably, between 1 and 75 m.
14. Method according to claim 1, comprising a step of depositing a bond coat onto said substrate and said insulating body prior to the step of depositing the electrical structure.
15. An integrated circuit comprising a substrate comprising: a substrate comprising a horizontal surface, at least one insulating body located on said substrate, said insulating body comprising a first wall extending from the horizontal surface of the substrate to a high point of said insulating body, a one-piece electrical structure made of an electrically conductive material extending on the horizontal surface of the substrate and the first wall of the insulating body, and circuit wherein the first wall is vertically angled and has a rising slope from the horizontal surface of the substrate to the high point of said insulating body, with the first wall comprising a horizontal component and a vertical component greater than 10 m, the ratio of inclination of the horizontal component over the vertical component is between 0.001 and 1.35.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0062] The invention shall be better understood when reading the following description, provided solely by way of example, and in reference to the annexed drawings wherein:
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[0073] Note that the figures show the invention in a detailed manner in order to implement the invention, said figures able of course to be used to better define the invention where applicable.
DETAILED DESCRIPTION
[0074] The method according to the invention allows for the integration of inductive passive 3D components onto a substrate as well as 3D interconnections that connect one or several active or passive components to a substrate.
[0075] A method for manufacturing a monolithic integrated circuit according to a first embodiment of the invention shall now be presented in reference to
[0076] Such interconnections are configured in particular for establishing electrical connections between different regions of an active or conductive zone of the substrate, between different active or conductive zones of the substrate or between active or conductive zones of several integrated circuits stacked and/or dispersed over the surface of the substrate. They can also form interconnection elements that can allow for the electrical connection of a discrete electronic component, i.e. not integrated into the monolithic circuit.
[0077]
[0078] In reference to
[0079] In a first step, in reference to
[0080] In this example, still in reference to
[0081] The second right angled wall 7d is decreasing in the system of coordinates X, Y but it however has a rising slope from the upper surface 1a of the substrate 1 to the upper horizontal surface 7c of the insulating body 7. The slopes are, in this example, symmetrical but it goes without saying that they could be different.
[0082] The inclination ratio of the horizontal component Cx over the vertical component Cy is between 0.001 and 1.35, preferably, between 0.01 and 1.
[0083] In this embodiment, the angled walls 7b, 7d are flat but it goes without saying that they could be different, in particular, curved as will be presented in what follows.
[0084] In reference to
[0085] Advantageously, given that the walls 7b, 7d of the insulating body 7 are angled, the walls 8b, 8d of the bond coat 8 are also angled as shown in
[0086] The bond coat 8, also called electrolytic growth layer, is formed in this example by the depositing of a metal material, in particular of an electrically conductive or semi-conductive material, able to promote the adhesion of the material comprising the electrical structure by electrolytic growth. By way of example, the bond coat 8 is a thin layer, with a thickness between 1 nm and 2 m made of titanium, chromium, tantalum, tungsten, aluminium, gold, copper, silver, nickel or a metal alloy such as and not limited to titanium/tungsten, nickel/boron or a metal/semi-conductor alloy such as and not limited to aluminium/silicon or other. Advantageously, this layer is carried out as a successive deposit of two or of several layers of metal, such as for example of titanium/copper, titanium/gold, chromium/gold, Titanium/Nickel/gold or other possible configurations.
[0087] The bond coat 8 is deposited by a conventional method of vertical depositing of a metal material known to those skilled in the art, in particular par cathode pulverisation, by thermal evaporation or by electrografting. During such a depositing, all of the surfaces of the substrate 1 and of the insulating body 7 are cleared and are as such easily reached by the metal material constituting the bond coat 8, and as such these surfaces are covered homogeneously and continuously.
[0088] Advantageously, it is not necessary to use an initiator, which reduces the number of technological steps as well as the costs and the time for manufacturing, limits the risk of defects and responds to the various weak points mentioned hereinabove.
[0089] In reference to
[0090] In this example, the layers of resin 4a, 4e are respectively deposited on the left lower horizontal portion 8a and the right lower horizontal portion 8e as shown in
[0091] Each layer of resin 4a, 4e having the structure sought is obtained by any suitable method known to those skilled in the art, in particular by lithography or inkjet printing. In this example, each layer of resin 4a, 4e has a substantial thickness, in particular a thickness between 10 m and 500 m. In the example shown, it has a thickness equal to about 150 m. The resin forming the layer of resin 4a, 4e is in particular a photosensitive resin having a resolution between 1 for 0.5 and 1 for 50, preferably between 1 for 2 and 1 for 25. In the example shown, the resin has a resolution of 1 for 15, i.e. the smallest width of the segments that can be obtained by photolithography is 10 m thick. It is as such possible to form patterns with a width greater than or equal to 10 m for a resin thickness of 150 m.
[0092] Advantageously, the mould formed by the layers of resin makes it possible to structure different types of interconnections. So as to allow for the housing of a body 70 (in particular one or several chips) which is thick and which cannot be thinned, it is advantageous to provide a cavity in the substrate for the mounting of said body 70. This makes it possible to limit the overall thickness of the integrated circuit. Thanks to the invention, it is possible to carry out interconnections in the cavity following the mounting of said body 70, in particular, in the adjacent cavities C1, C2 formed between the body 70 and the raised edge of the substrate 70 as shown in
[0093] According to a first embodiment, in reference to
[0094] According to a second embodiment, in reference to
[0095] Such interconnections 9-1, 9-2 make it possible to stack a substantial number of electronic chips in a cavity of the substrate while still having an integrated circuit of low thickness.
[0096] In reference to
[0097] Advantageously, given that the walls 8b, 8d of the bond coat 8 are angled, the electrolytic growth is improved, which improves the control of the thicknesses.
[0098] The electrical structure 9 is made from an electrically conductive material, and able to be deposited by electrolysis. It is advantageously made of copper.
[0099] Alternatively, it is made from gold or all other metals that allow for an electrolytic depositing.
[0100] The electrical structure 9 forms for example all or a portion of an electronic component, in particular of a passive electronic component such as an inductance, a transformer, an antenna, etc. It can also form an interconnection line, configured to connect together different regions of the substrate 1 and/or different regions of the substrate 1 and of the insulating body and/or different regions of the insulating body. The thickness of the electrical structure 9 depends on its electronic function. It also depends on the application of the circuit. By way of example, electrical structures 9 will be provided with higher thicknesses in a power amplifier circuit than in a digital circuit. For the purposes of information, the thickness of an electrical structure 9 is for example between 1 m and 150 m. After having formed the electrical structure 9, (
[0101] Finally, still in reference to
[0102] An integrated circuit such as shown in
[0103] A second embodiment of the invention is described in reference to
[0104] In reference to
[0105] Similar to flat angled walls, the curved angled walls 7f, 7g facilitate the depositing of the bond coat 8 as well as of the electrical structure 9.
[0106] Advantageously, the electrical structure 9 has the shape of a spire. To this effect, as shown in
[0107] Preferably, in reference to
[0108] Preferably, the insulating body 7 located between the substrate 1 and the bond coat 8 is removed in order to improve the performance of the inductances and of the inductive components at high frequencies, since this body has dielectric losses that are more substantial than those of air 90, 90.
[0109] The method according to the invention makes it possible to obtain, with a reduced number of technological steps, inductive passive components of high quality. Furthermore, it makes it possible to form electrical interconnections 90 comprising an angled wall 9f that connects various active components to a substrate 1 as shown in
[0110] A third embodiment of the invention is described in reference to
[0111] In the two preceding embodiments, the insulating body 7 was comprised of insulating material. In this third embodiment, the insulating body 7 comprises a body comprised of conductor and/or semi-conductor and/or magnetic and/or dielectric material 70 which is covered by an insulating layer 71 also called passivation or repassivation layer. The body comprised of conductor and/or semi-conductor and/or magnetic and/or dielectric material 70 comprises at least one first wall 70b extending from the horizontal surface of the substrate 1 to a high point of said body 70.
[0112] As shown in
[0113] Preferably, the insulating layer 71 is deposited by vacuum evaporation, by pulverisation or by spray in order to obtain an insulating layer of thickness that is relatively compliant on all of the walls (not too thin, not too thick).
[0114] The insulating layer 71 is deposited onto all of the walls (horizontal, vertical, angled, etc.) of the body 70 as well as on the substrate 1 in such a way as to fully insulate the body 70 comprised of conductor and/or semi-conductor and/or magnetic and/or dielectric material 70. A passivation/insulating of the body 70, in particular of the upper face, makes it possible to separate the interconnections from the connections present on the body 70 as well as from the latter, which reduced the interactions by electromagnetic coupling and consequently, electrical losses. In addition, this makes it possible to route interconnections above the connection pads of the body 70, which makes it possible to increase the routing density and to reduce the number of layers of metallisations required for the interconnection of high-density input-output systems. The cost of manufacturing is then reduced.
[0115] In this example, in reference to
[0116] Advantageously, the insulating layer 71 makes it possible to form a controlled inclination slope over the body comprised of conductor and/or semi-conductor and/or magnetic and/or dielectric material of which the first walls 70b are vertical or undercut. In the case where the walls of said body 70 are undercut, the insulating layer 71 fills a function of electrical insulation. The insulating layer 71 assure the physical continuity between the substrate 1 and the walls of said body 70, as such making it possible to carry out a continuous one-piece electrical structure. The insulating layer 71 as such authorises the formation of a one-piece electrical structure on a body comprised of conductor and/or semiconductor and/or magnetic and/or dielectric 70 material.
[0117] In order to control the inclination of the slope, the insulating layer 71 is deposited preferably by spray coating.
[0118] Preferably and according to the needs of the application, the method comprises a step of precise adjustment of the inclination of the slope using a technique of photolithography. In reference to
[0119] In practice, the thickness of the insulating layer 7, which is removed, is proportional to the dose of insulating received. In this embodiment, the mask 100 comprises a zone 101, configured to insulate the slope from the insulating layer 7, which comprises a plurality of patterns 103 of variable lengths and widths in such a way as to control the inclination of said slope precisely. Preferably, the zone 101 comprises a plurality of patterns 103 of which the width is decreasing according to the axis oriented from the top of the slope towards the bottom of the slope as shown in
[0120] After insulating, as shown in
[0121] This structuring can be carried out using one or several masks 100 and using one or several steps of insulating.
[0122] Very advantageously, the inclination of each slope can as such be adjusted individually, which increases the routing possibilities.
[0123] In reference to
[0124] The method according to the invention authorises by default the carrying out of multi-level interconnections 9 onto a substrate comprising a plurality of insulating bodies 7 dispersed and/or stacked vertically on the surface thereof (
[0125] Thanks to the method according to the invention, an increase in the manufacturing output is obtained and a substantial reduction in costs. The depositing in a single step of the electrical structure without preparation of the flanks makes it possible to obtain a base of continuous electrolytic growth over several levels in a fast manner and at least cost.
[0126] The method according to the invention as such allows for the manufacturing of integrated circuits, comprising active and passive components, forming one-piece conductive structures, in particular 3D interconnections and inductive passive components having very low losses. It makes it possible to, design and carry out RF and micro-wave power amplifiers of small size that have a high-power output and that therefore have a reduced consumption. It can also make it possible to implement an antenna directly on the integrated circuit. This method can also be used advantageously to assemble and interconnect on the Wafer-Level-Packaging scale miniaturised systems of the System-in-Package type. The use of the method is not limited to semiconductor substrates, it can be applied to other types of substrates such as glasses, alumina, polymers, PCB, etc. as well as on the flexible substrates (PET, Polyimide, etc.).