Flexible surface layer film for delivery of highly filled or low cross-linked thermally conductive interface pads

• US 6,657,297 B1
• Filed: 08/15/2002
• Issued: 12/02/2003
• Est. Priority Date: 08/15/2002
• Status: Expired due to Term

• Current Assignee: Henkel IP & Holding GmbH (Henkel AG & Co KGaA)
• Original Assignee: Berquist Company The (Henkel AG & Co KGaA)
• Inventors: Jewram, Radesh, Hanson, Kevin L., Seethamraju, Kasyap Venkata
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): HO, TU TU V
• Application Number:
  US10/219,210
• Time in Patent Office: 474 Days
• Field of Search: 257/720, 257/684, 257/712
• US Class Current: 257/720
• CPC Class Codes: B32B 27/20 using fillers, pigments, thixotroping agents
• CPC Class Codes: H01L 23/3735 Laminates or multilayers, e.g. direct bond copper ceramic substrates
• CPC Class Codes: H01L 23/3737 Organic materials with or without a thermoconductive filler
• CPC Class Codes: H01L 23/433 Auxiliary members in containers characterised by their shape, e.g. pistons
• 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: H01L 2924/12044 OLED
• CPC Class Codes: Y10T 428/12528 Semiconductor component

Abstract

A flexible plastic thermally conductive multilayer semiconductor mounting pad having a highly thermally conductive bulk layer with thermally conductive surface skin layers bonded integrally to opposed major surfaces thereof. The bulk layer and the surface skin layers are each filled with a finely divided thermally conductive particulate, with the skin layers being harder than the bulk layer and being blended with an amount of filler which is less than that present in the bulk layer.

Claims

1. In a flexible plastic thermally conductive multi-layer semiconductor mounting pad having a highly thermally conductive bulk layer with thermally conductive surface skin layers bonded integrally to at least one of a pair of opposed major surfaces thereof, said semiconductor mounting pad being characterized in that:

(a) said central bulk layer being filled with a finely divided thermally conductive particulate, and comprising a flexible polymeric resin matrix selected from the group consisting of silicone, epoxy, acrylic, polyurethane, polyester, and polybutadiene;

(1) said particulate being present in said polymeric matrix in an amount ranging from between about 10% and 85% by volume and being sufficient in amount to produce a bulk layer having a hardness of between 10-80 Shore 00;

(b) said surface skin layers having a thickness of between 2 and 50 microns and selected from a polymeric resin being compatible with the polymeric matrix of said bulk layer and selected from the group consisting of silicone, epoxy, acrylic, polyurethane, polyester, and polybutadiene, and with said surface layers being blended with a thermally conductive finely divided particulate filler in an amount ranging less than that present in said bulk layer and ranging from between about 5% and 60% by volume;

(1) the hardness of said skin layer being substantially greater than that of the bulk layer, and ranging from between about 20 Shore 00 and 60 Shore A.

2. The-semiconductor mounting pad as set forth in claim 1 wherein the polymeric resin selected for said bulk and skin layers is a blend of silicone elastomer and thermally conductive filler.

3. The semiconductor mounting pad as set forth in claim 1 wherein the polymeric resin selected for said skin layer is ethylene vinyl acetate co-polymer and said bulk layer is silicone elastomer.

4. The semiconductor mounting pad as set forth in claim 1 wherein said finely divided thermally conductive particulate filler is selected from the group consisting of alumina, boron nitride, aluminum nitride, graphite, silicon carbide, zinc oxide, copper powder, aluminum powder, and silver powder, other metallic powders, and blends thereof.

5. The semiconductor mounting pad as set forth in claim 1 wherein said finely divided particulate filler selected for said bulk and skin layers is alumina.

6. The semiconductor mounting pad as set forth in claim 1 wherein said finely divided thermally conductive particulate filler is a metallic powder selected from the group consisting of aluminum, copper and silver.

7. The semiconductor mounting pad as set forth in claim 1 wherein said bulk layer has a thermal conductivity ranging from between about 1 and 15 W/m.K.

8. The semiconductor mounting pad as set forth in claim 7 wherein said skin layers have a thermal conductivity ranging from between about 0.3-5 W/m.K.

9. The semiconductor mounting pad as set forth in claim 2 wherein said finely divided particulate filler is alumina.

10. The semiconductor mounting pad of claim 9 wherein said filler is present in said polymeric matrix in an amount ranging from between 20% and 50% by volume and wherein said polymeric matrix has a hardness ranging from between 20-50 Shore 00.

11. The semiconductor mounting pad of claim 10 wherein said finely divided particulate filler in said skin layers is present in an amount ranging from between 20% and 40% by volume.

12. The semiconductor mounting pad of claim 1 wherein a thermally conductive surface skin layer is bonded integrally to each of said opposed major surfaces of said bulk layer, and wherein the polymeric matrix for each skin layer is a different polymer.

13. The semiconductor mounting pad of claim 1 wherein a thermally conductive surface skin layer is bonded integrally to each of said opposed major surfaces, and wherein one of said skin layers is blended with a significantly greater amount of finely divided particulate filler than the other skin layer.