Method of eliminating uncontrolled voids in sheet adhesive layer

• US 20040140574A1
• Filed: 01/12/2004
• Published: 07/22/2004
• Est. Priority Date: 04/13/2001
• Status: Active Grant

• Current Assignee: STMicroelectronics Incorporated (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Incorporated (STMicroelectronics NV)
• Inventors: Chiu, Anthony M.
• Granted Patent: US 6,919,230 B2
• Time in Patent Office: Days
• US Class Current: 257/783
• CPC Class Codes: H01L 2224/29011 comprising apertures or cavities
• CPC Class Codes: H01L 2224/29101 the principal constituent melting at a temperature of less than 400°C
• CPC Class Codes: H01L 2224/2919 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/8319 Arrangement of the layer connectors prior to mounting
• CPC Class Codes: H01L 2224/8385 using a polymer adhesive, e.g. an adhesive based on silicone, epoxy, polyimide, polyester
• CPC Class Codes: H01L 24/29 of an individual layer connector
• CPC Class Codes: H01L 24/83 using a layer connector
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/01004 Beryllium [Be]
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01082 Lead [Pb]
• CPC Class Codes: H01L 2924/014 Solder alloys
• CPC Class Codes: H01L 2924/0665 Epoxy resin
• CPC Class Codes: H01L 2924/07802 not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/12042 LASER
• CPC Class Codes: H01L 2924/14 Integrated circuits

Abstract

A preformed adhesive layer for joining components within integrated circuit packaging includes venting slots for controlling the size and location of voids within an assembled integrated circuit package. Air randomly entrapped between the surfaces of the adhesive layer and adjoining components during assembly will generally release into the venting slots during subsequent assembly and/or mounting steps performed at elevated temperatures, rather than creating internal pressures causing separation of package components or releasing into the encapsulant. Die delamination and encapsulant void problems occurring during reflow or other assembly and mounting processes as a result of entrapped air are avoided.

Claims

1. For use in an integrated circuit package, an adhesive layer for affixing one package component to another comprising:

an adhesive material region; and

at least one venting slot extending within the adhesive material region for controlling a size and location of voids between said adhesive material region and components joined by said adhesive material region during packaging.

2. The adhesive layer as set forth in claim 1 wherein said at least one venting slot further comprises:

a plurality of venting slots each extending from a region proximate to a side or corner of a cavity hole within said adhesive material region towards a corresponding side or corner of a periphery of said adhesive material region.

3. The adhesive layer as set forth in claim 2 wherein each said venting slot is separated from said periphery of said adhesive material region by a width of adhesive material sufficiently narrow to permit diffusion of gas therethrough.

4. The adhesive layer as set forth in claim 3 wherein each said venting slot further comprises:

extensions extending along a periphery of said cavity hole.

5. The adhesive layer as set forth in claim 4 wherein said extensions are spaced from said cavity hole by adhesive material sufficiently wide to minimize diffusion of gas from said venting slots into said cavity hole.

6. The adhesive layer as set forth in claim 1 wherein said adhesive material region is formed of fiberglass impregnated with epoxy resin.

7. The adhesive layer as set forth in claim 1 wherein said adhesive material region is formed of polyimide film with B-staged polyimide adhesive resin.

8. The adhesive layer as set forth in claim 1 wherein said adhesive layer comprises a sheet forming a plurality of said adhesive material regions, each adhesive material region including said at least one venting slot.

9. An integrated circuit package comprising:

a first package component;

a second package component; and

an adhesive layer affixing said first and second package components to each other, said adhesive layer comprising;

an adhesive material region; and

at least one venting slot extending within the adhesive material region for controlling a size and location of voids between said adhesive layer and said first or second component during packaging.

10. The integrated circuit package as set forth in claim 9 wherein said at least one venting slot further comprises:

a plurality of venting slots each extending from a region proximate to a side or corner of a cavity hole within said adhesive material region towards a corresponding side or corner of a periphery of said adhesive material region.

11. The integrated circuit package as set forth in claim 10 wherein each said venting slot is separated from said periphery of said adhesive material region by a width of adhesive material sufficiently narrow to permit diffusion of gas therethrough.

12. The integrated circuit package as set forth in claim 11 wherein each said venting slot further comprises:

extensions extending along a periphery of said cavity hole.

13. The integrated circuit package as set forth in claim 12, wherein said extensions are spaced from said cavity hole by adhesive material sufficiently wide to minimize diffusion of gas from said venting slots into said cavity hole.

14. The integrated circuit package as set forth in claim 9, wherein said adhesive material region is formed of fiberglass impregnated with epoxy resin.

15. The integrated circuit package as set forth in claim 9, wherein said adhesive material region is formed of polyimide film with B-staged polyimide adhesive resin.

16. The integrated circuit package as set forth in claim 9 further comprising:

an integrated circuit die mounted within a die cavity within said first package component and affixed through a cavity hole within said adhesive material region to said second package component.

17. For use in an integrated circuit package, a method of affixing one package component to another comprising:

forming an adhesive material region; and

forming at least one venting slot extending within the adhesive material region for controlling a size and location of voids between said adhesive material region and components joined by said adhesive layer during packaging.

18. The method as set forth in claim 17 wherein the step of forming at least one venting slot extending within the adhesive material region for controlling a size and location of voids between said adhesive material region and components joined by said adhesive material region during packaging further comprises:

forming a plurality of venting slots each extending from a region proximate to a side or corner of a cavity hole within the adhesive material region towards a corresponding side or corner of a periphery of the adhesive material region.

19. The method as set forth in claim 18 wherein the step of forming a plurality of venting slots each extending from a region proximate to a side or corner of a cavity hole within the adhesive material region towards a corresponding side or corner of a periphery of the adhesive material region further comprises:

forming each venting slot to extend to a point separated from the periphery of the adhesive material region by a width of adhesive material sufficiently narrow to permit diffusion of gas therethrough; and

forming extensions of each venting slot extending along a periphery of the cavity hole, wherein the extensions are spaced from the cavity hole by adhesive material sufficiently wide to minimize diffusion of gas from the venting slots into the cavity hole.

20. The method as set forth in claim 17 further comprising:

forming a plurality of patterns for the adhesive material region within a sheet, each pattern including the at least one venting slot.

21. The method as set forth in claim 17 further comprising:

affixing a substrate having a die cavity therein to a second package component utilizing the adhesive material region.

22. The method as set forth in claim 21 further comprising:

mounting an integrated circuit die within the die cavity;

affixing the integrated circuit die to the second package component through the cavity hole; and

electrically connecting the integrated circuit die to conductive traces on the substrate.