PACKAGE FOR INTEGRATED CIRCUIT AND MANUFACTURING METHOD

Abstract

An encapsulation hood is fastened onto electrically conductive zones of a support substrate using springs. Each spring has a region in contact with an electrically conductive path contained in the encapsulation hood and another region in contact with a corresponding one of the electrically conductive zones. The fastening of the part of the encapsulation hood onto the support substrate compresses the springs and further utilizes a bead of insulating glue located between the compressed springs.

Claims

1. A package for an integrated circuit, comprising: a support substrate supporting at least one electronic chip; an encapsulation hood fastened onto the support substrate by a fastening device, wherein the encapsulation hood incorporates an electrically conductive path having at least two distinct ends; wherein the fastening device comprises: at least two springs respectively electrically coupling the two ends of the electrically conductive path to two electrically conductive zones of the support substrate, each spring having as a first free region in contact with one of said at least two distinct ends of the electrically conductive path or one of said two electrically conductive zones and a second region fastened onto another of said two electrically conductive zone or another of said at least two distinct ends of the electrically conductive path, respectively; and electrically insulating auxiliary attachment disposed between the springs and configured to fasten a part of the encapsulation hood located between the ends of said at least one conductive path onto the support substrate.

2. The package according to claim 1, wherein each spring is compressed.

3. The package according to claim 1, wherein the second region of each spring is fastened by an electrically conductive glue.

4. The package according to claim 1, wherein the auxiliary attachment includes an electrically insulating glue.

5. The package according to claim 1, wherein the electronic chip includes a source of optical radiation, and wherein the encapsulation hood includes an optical device optically coupled to said source.

6. A method for creating a package for an integrated circuit, comprising: fastening an encapsulation hood incorporating an electrically conductive path having at least two distinct ends onto a support substrate supporting at least one electronic chip and two electrically conductive zones; wherein fastening comprises: providing at least two electrically conductive springs, wherein each spring has a first region and a second region; leaving free the first region of each spring and placing it in contact with one of the two distinct ends of the electrically conductive path or one of the two electrically conductive zones of the support substrate; fastening the second region of each spring onto another of said two electrically conductive zones or onto another of the two distinct ends of the electrically conductive path, respectively, in such a way as to respectively electrically couple the two ends of the electrically conductive path to the two electrically conductive zones of the support substrate, securing part of the encapsulation hood located between the ends of said at least one conductive path onto the support substrate in an electrically insulating manner.

7. The method according to claim 6, wherein said fastening comprises compressing said springs.

8. The method according to claim 6, wherein fastening of the second region of each spring comprises using an electrically conductive glue.

9. The method according to claim 6, wherein securing comprises using an electrically insulating glue.

10. The method according to claim 6, wherein the electronic chip includes a source of optical radiation and the encapsulation hood includes an optical device optically coupled to said source.

11. A package, comprising: a support substrate having a mounting face including a first electrical zone and a second electrical zone; an electronic chip mounted to the mounting face; an encapsulation hood including an electrically conductive path extending from a first end to a second end, said first and second ends located at a bottom edge of the encapsulation hood; wherein a bottom edge of the encapsulation hood faces the mounting face of the support substrate; a spot of conductive glue covering each of the first and second electrical zones; a first electrically conductive spring having a U-shaped cross-section with a first leg secured by the spot of glue at the first electrical zone and a second leg in contact with the first end of the electrically conductive path at the bottom edge of the encapsulation hood; and a second electrically conductive spring having a U-shaped cross-section with a first leg secured by the spot of glue at the second electrical zone and a second leg in contact with the second end of the electrically conductive path.

12. The package according to claim 11, wherein each of the first and second electrically conductive springs is compressed by attachment of the mounting hood to the support substrate.

13. The package according to claim 12, further comprises an electrically insulating glue positioned between the bottom edge of the mounting hood and the support substrate to provide said attachment.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Other advantages and features of the invention will appear upon examination of the detailed description of implementations and embodiments, in no way limiting, and of the appended drawings in which:

[0042] FIG. 1 illustrates a package in accordance with the prior art;

[0043] FIG. 2 illustrates a spring;

[0044] FIG. 3 schematically illustrates a cross-section of a package using the spring of FIG. 2; and

[0045] FIGS. 4 to 7 illustrate an embodiment of a method of manufacturing the package of FIG. 3.

DETAILED DESCRIPTION

[0046] In FIG. 2, the reference 900 designates a spring, for example a microspring, usable in the fastening and the electric connection of the electrically conductive path incorporated into the encapsulation hood and the corresponding electrically conductive zone of the support substrate.

[0047] In this example, the microspring is in the shape of a U with a length L of approximately 0.1 mm to 2 mm and a distance h of approximately 0.05 mm to 0.50 mm between the first region, for example a first face or leg, 901 of the spring and the second region, for example a second face of leg, 902 of the spring.

[0048] The height h is the height when the spring is not loaded.

[0049] The material forming this spring is electrically conductive and can be, for example, made of steel, stainless steel or another metal, and provided or not with a finish (for example nickel, nickel and gold or nickel and palladium and gold).

[0050] FIG. 3 schematically illustrates a cross-section of a package 100 according to one implementation of the invention.

[0051] This package 100 includes a support substrate 200 including a network of interconnections embedded in the body of the support substrate and allowing in particular to electrically connect metal tracks located on the mounting face of the support substrate to for example a ball grid (in the case of a package of the BGA type) located on the opposite face of the support substrate.

[0052] The support substrate 200 supports on its mounting face an electronic chip 500 equipped in this example with a source of light radiation 1100, for example a laser source.

[0053] An encapsulation hood 300, incorporating an electrically conductive path 400, is fastened onto the mounting face of the support substrate by a fastening device, the structure of which will be described in more detail below.

[0054] Once the encapsulation hood has been assembled onto the support substrate, the assembly arranges an inner housing 600 in which the electronic chip 500 is located.

[0055] Moreover, in this example, the encapsulation hood 400 includes an optical device 1000, for example a lens, located in optical coupling with the laser source 500. For example, this lens is located facing the laser source 500.

[0056] The electrically conductive path 400 includes a distinct first end 3000 and second end 3100 located at a bottom edge of the encapsulation hood.

[0057] Moreover, the support substrate 200 includes on its mounting face a first electrically conductive zone 7000 and a second electrically conductive zone 7100.

[0058] As will now be shown, the first end 3000 of the electrically conductive path 400 is electrically coupled to the first electrically conductive zone 7000 while the second end 3100 of the electrically conductive path 400 is electrically coupled to the second electrically conductive zone 7100.

[0059] This coupling is carried out using the fastening device in the form of a spot of electrically conductive glue and a spring such as that illustrated in FIG. 2.

[0060] More precisely, the second region 902 of the spring 900 is glued onto the spot of conductive glue 8000 that covers the first electrically conductive zone 7000.

[0061] Moreover, the first region 901 of the spring 900 is not fastened, but it is free and in contact with the first end 3000 of the electrically conductive path 400.

[0062] It can be seen in this example that the spring 900 is compressed. Therefore, the contact between the first region 901 of the spring 900 and the first end 3000 of the electrically conductive path 400 is obtained by the spring effect of the spring which is stressed, here in compression.

[0063] There is the same structure for the electric coupling between the second end 3100 of the electrically conductive path 400 and the second electrically conductive zone 7100 of the support substrate.

[0064] More precisely, this electrical coupling is obtained by a spring 911, analogous to the spring 900, compressed, and having its first region 911 in contact with the second end 3100 of the path 400 by the spring effect, and having its second region 912 glued onto the spot of electrically conductive glue 8100 covering the second electrically conductive zone 7100.

[0065] Moreover, as illustrated in FIG. 7, which will be addressed in more detail below during the disclosure of an example of a manufacturing method, it can be seen that to maintain the encapsulation hood fastened onto the support substrate, there is an auxiliary attachment, for example a bead of electrically insulating glue 9100 disposed on the periphery of the mounting face of the support substrate extending between the spots of conductive glue 8000 and 8100 and allowing to fasten, onto the support substrate, the part of the encapsulation hood located between the two springs 900 and 910.

[0066] Reference is now made more particularly to FIGS. 4 to 7 to illustrate an embodiment of a method according to the invention.

[0067] In each of FIGS. 4 to 7, the upper part of the drawing shows a schematic cross-section of the package being manufactured while the lower part of the figure schematically shows a top view of the mounting face of the support substrate 200.

[0068] In FIG. 4, on the periphery of the mounting face of the support substrate 200, two spots of electrically conductive glue 8000 and 8100 covering the two electrically conductive zones 7000 and 7100 of the support substrate are deposited, and the second regions 902 and 912 of the two springs 900 and 910 are fastened onto these two spots of glue 8000 and 8100, respectively.

[0069] The first regions 901 and 911 of these springs remain free. Moreover, in this configuration, the springs are not stressed.

[0070] Any type of glue can be used that is electrically conductive, conventional and well known to a person skilled in the art.

[0071] Then, as illustrated in FIG. 5, a bead of electrically insulating glue 9000 is deposited on the mounting face of the substrate 200 between the two spots of electrically conductive glue 8000 and 8100.

[0072] This non-insulating glue can be, for example, a glue that is hardenable via UV radiation, conventional and well known to a person skilled in the art.

[0073] Then, as illustrated in FIG. 6, after having mounted the chip on the support substrate and carrying out its connection by welding of wires (wire bonding) and after having created in a conventional and known manner the encapsulation hood incorporating the electrically conductive path and the optical device 1000, on the one hand the encapsulation hood is applied onto the free regions 901 and 911 of the springs 900 and 910 and, on the other hand, the part of the encapsulation hood located between the two springs is applied onto the bead of insulating glue 9000, by exerting a force ST60.

[0074] By the application of this force ST60, the two springs 900 and 910 are compressed and their first respective free regions 901 and 911 are in contact with the corresponding ends 3000 and 3100 of the electrically conductive path 400, and the encapsulation hood adheres to the support substrate via the bead of insulating glue 9000.

[0075] Then, while maintaining the compression force ST60, as illustrated in FIG. 7, exposure of the package of FIG. 6 to ultraviolet radiation ST70 is carried out in such a way as to harden the bead of insulating glue and obtain in fine a bead of insulating hardened glue 9100.

[0076] The invention is not limited to the implementations and embodiments that have just been described and encompasses all the alternatives thereof.

[0077] Thus, the spots of electrically conductive glue 8000 and 8100 can be replaced by solder pads or by any other electric connection means.

[0078] Likewise, it would be possible to fasten the regions 901 and 911 of the springs onto the two ends 3000 and 3100 of the electrically conductive path 400 and leave free the regions 902 and 912 of these springs in order for them to come in contact with the two electrically conductive zones 7000 and 7100 of the support substrate.

[0079] In this case the regions 902 and 912 would be considered to be the first free regions of these springs and the regions 901 and 911 would be considered to be the second fastened regions.

[0080] Finally, it would be possible to provide, instead of a single electrically conductive path 400, a network of electrically conductive paths incorporated into the encapsulation hood with a corresponding set of pairs of spots of conductive glue for example.