Thermal interface apparatus, systems, and methods

• US 20040256720A1
• Filed: 06/10/2003
• Published: 12/23/2004
• Est. Priority Date: 06/10/2003
• Status: Active Grant

• Current Assignee: Beijing Xiaomi Mobile Software Co., Ltd. (Xiaomi Corp.)
• Original Assignee: Intel Corporation
• Inventors: Tan, Pek Chew, Tay, Cheng Siew, Yap, Eng Hooi
• Granted Patent: US 7,400,040 B2
• Time in Patent Office: Days
• US Class Current: 257/720
• CPC Class Codes: H01L 23/3735 Laminates or multilayers, e.g. direct bond copper ceramic substrates
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• 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 2201/068 wherein the coefficient of thermal expansion is important
• CPC Class Codes: H05K 3/4602 characterized by a special circuit board as base or central core whereon additional circuit layers are built or additional circuit boards are laminated
• CPC Class Codes: H05K 3/4641 having integrally laminated metal sheets or special power cores

Abstract

An apparatus and system, as well as fabrication methods therefor, may include a substrate coupled to a first material and a second material. The first and second materials may comprise adjacent metals, and may have different coefficients of thermal expansion sufficient to reduce the amount of substrate warp that can occur due to heating and cooling.

Claims

1. An apparatus, comprising:

a substrate;

a first material coupled to the substrate and having a first coefficient of thermal expansion; and

a second material coupled to the substrate and having a second coefficient of thermal expansion different from the first coefficient of thermal expansion to reduce an amount of warp across a surface of the substrate within a selected temperature range.

2. The apparatus of claim 1, wherein the first material is adjacent the second material.

3. The apparatus of claim 1, wherein the first material comprises a metal.

4. The apparatus of claim 3, wherein the second material comprises a metal.

5. The apparatus of claim 1, wherein the substrate comprises a ball grid array.

6. The apparatus of claim 1, wherein the substrate is included in a printed circuit board.

7. The apparatus of claim 1, wherein the first material and the second material each occupy a substantially similar portion of the substrate.

8. The apparatus of claim 1, wherein the first material and the second material are embedded in the substrate.

9. The apparatus of claim 1, wherein the first material is located between the second material and a die coupled to the substrate, and wherein the first material has a higher coefficient of thermal expansion than a coefficient of thermal expansion of the second material.

10. The apparatus of claim 1, wherein the first material is located between the second material and a die coupled to the substrate, and wherein the second material has a higher coefficient of thermal expansion than a coefficient of thermal expansion of the first material.

11. The apparatus of claim 1, wherein a coefficient of thermal expansion difference ratio between the first material and the second material is less than about 10:

1.

12. A system, comprising:

a wireless transceiver;

a substrate coupled to the wireless transceiver,

a first material coupled to the substrate and having a first coefficient of thermal expansion; and

a second material coupled to the substrate and having a second coefficient of thermal expansion different from the first coefficient of thermal expansion to reduce an amount of warp across a surface of the substrate within a selected temperature range.

13. The system of claim 12, further comprising:

a display coupled to a processor and the wireless transceiver.

14. The system of claim 13, wherein the substrate has a planar surface area, and wherein the first material and the second material each have a surface area greater than about 60% of the planar surface area.

15. The system of claim 13, wherein the wireless transceiver is coupled to an antenna.

16. A method, comprising:

coupling a first material having a first coefficient of thermal expansion to a substrate; and

coupling a second material to the substrate, the second material having a second coefficient of thermal expansion different from the first coefficient of thermal expansion to reduce an amount of warp across a surface of the substrate within a selected temperature range.

17. The method of claim 16, further comprising:

coupling a die to the substrate.

18. The method of claim 16, wherein coupling the first material and the second material to the substrate further comprises:

embedding the first material and the second material in the substrate.

19. The method of claim 16, further comprising:

determining an amount of warp across a surface of the substrate over a selected temperature range.

20. The method of claim 16, further comprising:

coupling the first material to the second material.

21. The method of claim 20, further comprising:

coupling a wireless transceiver to a circuit coupled to the substrate.