Method of attaching die to circuit board with an intermediate interposer

• US 8,481,861 B2
• Filed: 06/09/2011
• Issued: 07/09/2013
• Est. Priority Date: 06/27/2007
• Status: Active Grant

• Current Assignee: Hamilton Sundstrand Corporation (Rtx Corporation)
• Original Assignee: Hamilton Sundstrand Corporation (Rtx Corporation)
• Inventors: Cooney, Robert C., Wilkinson, Joseph M.
• Primary Examiner(s): Chen, Xiaoliang
• Application Number:
  US13/156,536
• Publication Number:
  US 20110232952A1
• Time in Patent Office: 761 Days
• Field of Search: 174/257, 174/256, 174/258, 174/259, 174/260, 174/261, 174/262, 174/524, 174/527, 361/306.2, 361/306.3, 361/748, 361/751, 361/760, 361/767, 257/700, 257/712, 257/774, 257/777, 257/778, 257/780, 257/782, 228/5.5, 228/180.22, 428/209, 428/403, 438/108, 438/118, 438/460, 438/613, 298/30, 298/43, 298/46
• US Class Current: 174/257
• 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 23/3735 Laminates or multilayers, e.g. direct bond copper ceramic substrates
• CPC Class Codes: H01L 24/29 of an individual 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 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/014 Solder alloys
• CPC Class Codes: H01L 2924/0665 Epoxy resin
• CPC Class Codes: H01L 2924/1306 Field-effect transistor [FET]
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/351 Thermal stress
• CPC Class Codes: H01L 2924/3512 Cracking
• CPC Class Codes: H05K 1/0271 Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion
• CPC Class Codes: H05K 1/141 One or more single auxiliary printed circuits mounted on a main printed circuit, e.g. modules, adapters H05K1/142 and H05K1/147 take precedence
• CPC Class Codes: H05K 2201/068 wherein the coefficient of thermal expansion is important
• CPC Class Codes: H05K 2201/10378 Interposers
• CPC Class Codes: H05K 2201/10674 Flip chip
• CPC Class Codes: H05K 3/3436 having an array of bottom contacts, e.g. pad grid array or ball grid array components
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/49126 : Assembling bases
• CPC Class Codes: Y10T 29/49149 : by metal fusion bonding
• CPC Class Codes: Y10T 29/49155 : Manufacturing circuit on or in base
• CPC Class Codes: Y10T 428/24917 : including metal layer
• CPC Class Codes: Y10T 428/2991 : Coated

Abstract

A die having a base formed of a first material is connected to a board having a base formed of a second material. An interposer having a coefficient of thermal expansion intermediate coefficients of thermal expansion of the first and second materials is positioned between the die and the board.

Claims

1. A printed circuit board comprising:

a board having a substrate formed of a first material having a first coefficient of thermal expansion, and having circuit traces;

a die secured to said board, said die having circuit traces electrically connected to said board circuit traces, and said die having a base formed of a second material having a second coefficient of thermal expansion different than said first coefficient of thermal expansion;

an interposer material positioned between said die and said board, said interposer having an electrical connection connecting said die circuit traces to said board circuit traces, said interposer being formed of a third material having a coefficient of thermal expansion intermediate said first and second coefficients of thermal expansion;

wherein said interposer includes a base material with a plurality of openings, said openings receiving a conductive material to connect said die to said board; and

wherein said interposer is formed of a polyimide of bismuth telluride.

2. The printed circuit board as set forth in claim 1, wherein said base material includes a solid plate having said openings, with said conductive material extending through said openings to connect said die to said board.

3. The printed circuit board as set forth in claim 1, wherein said base material includes a metal screen, with openings in the screen allowing said conductive material to connect said die to said board.

4. The printed circuit board as set forth in claim 1, wherein said die is a switch.

5. The printed circuit board as set forth in claim 4, wherein said switch is a field effect transistor.

6. The printed circuit board as set forth in claim 1, wherein a first layer of conductive material is positioned between said interposer and said die, and a second layer of conductive material is positioned between said interposer and said board, with said connection extending through said interposer for connecting said first and second layers.

7. The printed circuit board as set forth in claim 6, wherein said first material is a glass filled epoxy.

8. The printed circuit board as set forth in claim 7, wherein said second material is silicon.

9. The printed circuit board as set forth in claim 1, wherein said interposer is formed of a powdered metal injection molding compound.

10. The printed circuit board as set forth in claim 1, wherein said conductive material is provided through said openings such that said conductive material directly contacts both said die and said board.