Heat sink chip package and method of making

• US 6,122,171 A
• Filed: 07/30/1999
• Issued: 09/19/2000
• Est. Priority Date: 07/30/1999
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Akram, Salman, Kinsman, Larry
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): CHERVINSKY, BORIS LEO
• Application Number:
  US09/364,351
• Time in Patent Office: 417 Days
• Field of Search: 361/690, 361/702, 361/704, 361/707, 361/709, 361/717-721, 361/760, 361/761, 361/764, 257/706, 257/707, 257/712, 257/713, 257/721, 165/80.3, 165/185, 174/16.3, 174/252
• US Class Current: 361/704
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/4824 Connecting between the body and an opposite side of the item with respect to the body
• CPC Class Codes: H01L 2224/73215 Layer and wire connectors
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83 using a layer connector
• CPC Class Codes: H01L 2224/85 using a wire connector
• CPC Class Codes: H01L 2224/85399 Material
• CPC Class Codes: H01L 2224/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 2225/1023 the support being an insulating substrate
• CPC Class Codes: H01L 2225/1058 Bump or bump-like electrical connections, e.g. balls, pillars, posts
• CPC Class Codes: H01L 2225/1094 Thermal management, e.g. cooling
• CPC Class Codes: H01L 23/3121 a substrate forming part of the encapsulation
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 25/105 the devices being of a type provided for in group H01L27/00
• 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 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15311 : being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/1532 : the connection portion being formed on the die mounting surface of the substrate
• CPC Class Codes: H01L 2924/207 : Diameter ranges

Abstract

The present invention relates to enhanced thermal management of a microelectronic device package on a printed circuit board (PCB) having a solder ring or dam that encompasses a ball array. The ring or dam bears stress from disparate coefficients of mechanical expansion between the PCB and the ball array.

Claims

1. An integrated circuit chip package having a geometric center and comprising:

an integrated circuit (IC) chip having an active surface opposite an inactive surface;

a printed circuit board (PCB) having a first side opposite a second side and having said IC chip mounted thereon;

a ball array disposed on the first side of the PCB;

a first heat sink disposed upon and in thermal communication with the first side of the PCB, the ball array being located between the first heat sink and the geometric center of the integrated circuit chip package; and

a second heat sink disposed upon the second side of the PCB, wherein the active surface of the IC chip is disposed against the second side of the PCB.

2. An integrated circuit chip package according to claim 1, wherein the first heat sink comprises a plurality of heat sinks.

3. An integrated circuit chip package according to claim 1, wherein:

said one of said first and second sides of the PCB has a periphery with two pairs of parallel opposite edges, and

the first heat sink is parallel to one of the opposite edges.

4. An integrated circuit chip package according to claim 3, wherein the first heat sink comprises a plurality of heat sinks.

5. An integrated circuit chip package according to claim 1, wherein the PCB has a slot through which bond wires make electrical connection to the IC chip.

6. An integrated circuit chip package according to claim 1, wherein the ball array comprises a plurality of rows.

7. An integrated circuit chip package according to claim 1, the printed circuit board further comprising:

a via extending through the PCB and having electrically conductive material therein by which the first heat sink and the second heat sink make physical contact.

8. An integrated circuit chip package according to claim 1, wherein the first heat sink is composed of a tin alloy.

9. An integrated circuit chip package according to claim 8, wherein the alloy includes tin and at least one element selected from In, Ag, Pb, and combinations thereof.

10. An integrated circuit chip package according to claim 1, wherein the first heat sink and the ball array are composed of a tin alloy.

11. An integrated circuit chip package according to claim 10, wherein:

the alloy includes tin and at least one element selected from In, Ag, Pb, and combinations thereof.

12. An integrated circuit chip package having a geometric center and comprising:

an integrated circuit (IC) chip having an active surface opposite an inactive surface;

a printed circuit board (PCB) having a first side opposite a second side and having said IC chip mounted thereon;

a ball array disposed upon one of said first and second sides of the PCB; and

a first heat sink disposed upon and in thermal communication with said one of said first and second sides of the PCB the ball array being located between the first heat sink and the geometric center of the integrated circuit chip package, wherein one of the first and second sides of the PCB has disposed thereon both;

the active surface of the IC chip; and

a second heat sink that is in thermal communication with said one of the first and second sides of the PCB.

13. An integrated circuit chip package having a geometric center and comprising:

an integrated circuit (IC) chip having an active surface opposite an inactive surface;

a printed circuit board (PCB) having a first side opposite a second side and having said IC chip mounted thereon;

a ball array disposed upon one of said first and second sides of the PCB; and

a first heat sink disposed upon and in thermal communication with said one of said first and second sides, the ball array being located between the first heat sink and the geometric center of the integrated circuit chip package, wherein;

the active surface of the integrated circuit chip is disposed against the second side of the PCB;

second heat sink is disposed upon the second side of the PCB; and

the second heat sink includes a portion that is attached to the IC chip.

14. An integrated circuit chip package having a geometric center and comprising:

an integrated circuit (IC) chip having an active surface opposite an inactive surface;

a printed circuit board (PCB) having a first side opposite a second side and having said IC chip mounted thereon;

a ball array disposed upon one of said first and second sides of the PCB; and

a first heat sink disposed upon and in thermal communication with said one of said first and second sides, the ball array being located between the first heat sink and the geometric center of the integrated circuit chip package, wherein;

the active surface of the IC chip is disposed against the second side of the PCB;

a second heat sink is disposed upon the second side of the PCB;

the second heat sink includes a portion that is attached to the IC chip; and

the portion that is attached to the IC chip is integral with the second heat sink.

15. An integrated circuit chip package having a geometric center and comprising:

an integrated circuit (IC) chip having an active surface opposite an inactive surface;

a printed circuit board (PCB) having a first side opposite a second side and having said IC chip mounted thereon;

a ball array disposed upon one of said first and second sides of the PCB; and

a first heat sink disposed upon and in thermal communication with said one of said first and second sides, the ball array being located between the first heat sink and the geometric center of the integrated circuit chip package, wherein;

the active surface of the IC chip is disposed against the second side of the PCB;

the first heat sink and the ball array are disposed upon the first side of the PCB;

the first heat sink has an interface area upon the first side of the PCB;

a second heat sink is disposed upon the second side of the PCB; and

the second heat sink has an interface area upon the second side of the PCB that is larger than the interface area of the first heat sink on the first side of the PCB.

16. An integrated circuit chip package having a geometric center and comprising:

an integrated circuit (IC) chip having an active surface opposite an inactive surface;

a printed circuit board (PCB) having a first side opposite a second side and having said IC chip mounted thereon;

a ball array disposed upon one of said first and second sides of the PCB; and

a first heat sink disposed upon and in thermal communication with said one of said first and second sides the ball array being located between the first heat sink and the geometric center of the integrated circuit chip package, wherein;

the inactive surface of the IC chip is disposed upon the PCB;

the IC chip is disposed against a first side of the PCB;

the ball array and the first heat sink are disposed against a second side of the PCB; and

a second heat sink is disposed upon the first side of the PCB.

17. An integrated circuit chip package according to claim 16, wherein the PCB further comprises:

a via extending through the PCB having electrically conductive material therein by which the first heat sink and the second heat sink make physical contact.

18. An integrated circuit chip package having a geometric center and comprising:

an integrated circuit (IC) chip having an active surface opposite an inactive surface;

a printed circuit board (PCB) having a first side opposite a second side and having said IC chip mounted thereon;

a ball array disposed upon one of said first and second sides of the PCB; and

a first heat sink disposed upon and in thermal communication with said one of said first and second sides, the ball array being located between the first heat sink and the geometric center of the integrated circuit chip package, wherein;

the inactive surface of the IC chip is located above the PCB;

the IC chip is disposed against the first side of the PCB;

the ball array and the first heat sink are disposed against the second side of the PCB;

a second heat sink is disposed upon the second side of the PCB opposite the IC chip; and

the first heat sink and the second heat sink are an integral unit.

19. A method of making a chip package having a geometric center, the method comprising:

mounting an integrated circuit (IC) chip having an active surface opposite an inactive surface upon a printed circuit board (PCB) having a first side opposite a second side;

forming a ball array upon the first side of the PCB;

forming a first heat sink upon the first side of the PCB, the ball array being located between the first heat sink and the geometric center of the chip package; and

forming a second heat sink disposed upon the second side of the PCB, wherein the active surface of the IC chip is disposed against the second side of the PCB.

20. The method according to claim 19, wherein:

the active surface of IC chip is disposed against the second side of the PCB;

forming said second heat sink upon the second side of the PCB includes forming a portion thereof that is attached to the IC chip such that heat generated at the IC chip during the operation thereof is directed around the ball array and toward the first heat sink by conducting heat through the portion attached to the IC chip.

21. A method of making a chip package having a geometric center the method comprising:

mounting an integrated circuit (IC) chip having an active surface opposite an inactive surface upon a printed circuit board (PCB), the PCB having a first side opposite a second side;

forming a ball array upon one of said first and second sides of the PCB;

forming a first heat sink upon said one of said first and second sides of the PCB, the ball array being located between the first heat sink and the geometric center of the chip package, wherein;

the ball array and the first heat sink are upon the first side of the PCB; and

the active surface of IC chip is disposed against the second side of the PCB;

forming a second heat sink upon the second side of the PCB; and

forming a die attach in thermal communication with both the second heat sink and the IC chip such that operating the IC chip conducts heat through the die attach.

22. An integrated circuit chip package having a geometric center, the package method comprising:

a pair of integrated circuit (IC) chips each having an active surface opposite an inactive surface and each said IC chip being mounted by the active surface thereof upon a second side of a printed circuit board (PCB) that is opposite a first side;

a pair of first ball arrays each disposed upon the first side of the PCB;

a pair of central ball arrays each disposed upon the first side of the PCB;

a central heat sink disposed upon the first side of the PCB between;

the pair of first ball arrays;

the pair of central ball arrays; and

the pair of IC chips;

an outside heat sink disposed upon and in thermal communication with the periphery of the first side of the PCB, wherein each said;

first ball array of the pair of first ball arrays;

central ball array of the pair of central ball arrays; and

IC chip of the pair of IC chips is located on opposite sides of the geometric center of the integrated circuit chip package.

23. An integrated circuit chip package according to claim 22, wherein:

the pair of first ball arrays;

the pair of central ball arrays;

the pair of IC chips; and

the outside heat sink are symmetrical about the geometric center of the integrated circuit chip package.

24. An integrated circuit chip package according to claim 22, wherein the outside heat sink comprises a plurality of heat sinks.

25. An integrated circuit chip package according to claim 22, wherein the pair of IC chips comprise a central processing chip and a memory chip.

26. An integrated circuit chip package according to claim 22, wherein the integrated circuit chip package is symmetrical about its geometric center.