Method of flip chip assembly

• US 5,723,369 A
• Filed: 03/14/1996
• Issued: 03/03/1998
• Est. Priority Date: 03/14/1996
• Status: Expired due to Term

• Current Assignee: Bell Semiconductor, LLC (Hilco Inc. (d/b/a Hilco Global))
• Original Assignee: LSI Logic Corporation (Broadcom, Inc.)
• Inventors: Barber, Ivor G.
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): LEBENTRITT, MICHAEL
• Application Number:
  US08/615,865
• Time in Patent Office: 719 Days
• Field of Search: 437/209, 437/220, 257/787, 438/106, 438/107, 438/108, 438/110, 438/112, 438/122, 438/123, 438/127
• US Class Current: 438/106
• CPC Class Codes: H01L 2224/13111 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/16227 the bump connector connecting to a bond pad of the item
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• CPC Class Codes: H01L 2224/81801 Soldering or alloying
• CPC Class Codes: H01L 23/3121 a substrate forming part of the encapsulation
• CPC Class Codes: H01L 23/49816 Spherical bumps on the substrate for external connection, e.g. ball grid arrays [BGA]
• CPC Class Codes: H01L 24/81 using a bump 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 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01023 Vanadium [V]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/0105 Tin [Sn]
• CPC Class Codes: H01L 2924/01074 Tungsten [W]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15174 : in different layers of the multilayer substrate
• CPC Class Codes: H01L 2924/15311 : being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/181 : Encapsulation

Abstract

To assemble a flip chip in a package, the back of the flip chip is coated with a heat conductive material and a heat conductive substrate is attached to the heat conductive material. Solder bumps are attached to the front of the flip chip and to a package substrate to mount the flip chip on the package, leaving a space between the flip chip and the package substrate. The space between the flip chip and the package substrate is under filled with a heat conductive media, and the flip chip is encapsulated against the package substrate with a peripheral mold such that at least a portion of the conductive substrate remains exposed. A final package is formed by electrical connectors attached to the package substrate.

Claims

1. A method of assembling a flip chip in a package comprising:

coating the back of the flip chip with a heat conductive adhesive material,

attaching a heat conductive substrate to the heat conductive material,

mounting the flip chip to a package substrate using solder bumps attached between the front of the flip chip and the package substrate, there being a space left between the flip chip and the package substrate,

under filling the space between the flip chip and the package substrate with a heat conductive media,

encapsulating the flip chip against the package substrate with a peripheral mold such that at least a portion of the conductive substrate remains exposed, and

attaching electrical connectors to the package substrate, to form the package.

2. The method of claim 1 wherein the heat conductive material comprises epoxy.

3. The method of claim 1 wherein the heat conductive substrate comprises copper.

4. The method of claim 1 wherein the heat conductive media comprises epoxy.

5. The method of claim 1 wherein the peripheral mold comprises epoxy.

6. The method of claim 1 wherein the electrical connectors comprise solder balls.

7. A method of assembling a flip chip in a package comprising:

coating a heat conductive substrate with a heat conductive material,

attaching the heat conductive adhesive material to the back of the flip chip,

mounting the flip chip to a package substrate using solder bumps attached between the front of the flip chip and the package substrate, there being a space left between the flip chip and the package substrate,

under filling the space between the flip chip and the package substrate with a heat conductive media,

encapsulating the flip chip against the package substrate with a peripheral mold such that at least a portion of the conductive substrate remains exposed, and

attaching electrical connectors to the package substrate, to form the package.

8. The method of claim 7 wherein the heat conductive material comprises epoxy.

9. The method of claim 7 wherein the heat conductive substrate comprises a material selected from the group consisting of copper, copper/tungsten, aluminum, and ceramic.

10. The method of claim 7 wherein the heat conductive media comprises epoxy.

11. The method of claim 7 wherein the peripheral mold comprises epoxy.

12. The method of claim 7 wherein the electrical connectors comprise solder balls.