Multi-layer structure and method for forming a thermal interface with low contact resistance between a microelectronic component package and heat sink

• US 6,372,997 B1
• Filed: 02/25/2000
• Issued: 04/16/2002
• Est. Priority Date: 02/25/2000
• Status: Expired due to Term

• Current Assignee: Laird Technologies Incorporated (DuPont de Nemours, Inc.)
• Original Assignee: Thermagon, Inc. (Laird Limited)
• Inventors: Hill, Richard F., Hampton, Forest III
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): VU, QUYNH-NHU HOANG
• Application Number:
  US09/513,483
• Time in Patent Office: 781 Days
• Field of Search: 174/252, 174/260, 174/255, 174/52.4, 174/52.2, 174/52.3, 428/645, 428/646, 428/647, 428/648, 428/657, 428/658, 428/673, 361/707, 361/709, 361/710, 361/711, 361/717, 361/718, 361/719, 361/720, 257/707, 257/706
• US Class Current: 174/252
• CPC Class Codes: H01L 23/4275 by melting or evaporation of solids
• 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 2924/3011 Impedance
• CPC Class Codes: Y10S 165/907 Porous

Abstract

A multi-layer solid structure and method for forming a thermal interface between a microelectronic component package and a heat sink so that the structure has a total thermal resistance of no greater than about 0.03° C.-in²/W at a pressure of less than 100 psi. The structure comprises at least two metallic layers each of high thermal conductivity with one of the two layers having phase change properties for establishing low thermal resistance at the interface junction between the microelectronic component package and the heat sink.

Claims

1. A multi-layer solid metallic thermal interface structure for placement between a microelectronic component package and a heat sink so as to provide a total thermal resistance of no greater than about 0.03°

C.-in²/W at a pressure of less than 100 psi comprising at least two solid metallic layers of high thermal conductivity superimposed upon one another to form a sandwich in cross section with one of the two solid layers having a thickness of less than about 2 mils and formed of a metallic material composition having phase change properties whereby a low thermal resistance is established at the interface junction between the microelectronic component package and the heat sink.

2. A multi-layer solid metallic thermal interface structure as defined in claim 1 wherein one of the two high thermal conductivity layers has a dendritic surface in contact with the other high thermal conductivity.

3. A multi-layer solid metallic thermal interface structure as defined in claim 1 consisting of at least three high conductivity layers comprising an intermediate solid core composed of a high thermal conductivity metal or metal alloy and a solid layer on each opposite side thereof composed of a metallic material having phase change properties with each layer on each opposite side of said solid core having a thickness of less than about 2 mils.

4. A multi-layer solid metallic thermal interface structure as defined in claim 3 wherein the composition of said solid core is selected from the transition elements of row 4 in the periodic table in addition to magnesium and aluminum from row 3 of the periodic table and alloys thereof.

5. A multi-layer solid structure as defined in claim 4 wherein said layers having phase change properties are low melting metal alloys selected from the group of elements consisting of indium, bismuth, tin, lead, cadmium, gallium, zinc, silver and combinations thereof.

6. A multi-layer solid structure as defined in claim 5 wherein said low melting metal alloys comprise at least between 19 wt %-70 wt % indium and 30 wt %-50 wt % bismuth.

7. A multi-layer solid structure as defined in claim 1 wherein the layer having phase change properties is superimposed on only a limited surface area of said other layer for forming an exposed border in a configuration at least substantially surrounding said limited surface area.

8. A multi-layer solid structure as defined in claim 3 wherein each layer having phase change properties is superimposed on only a limited surface area of said other layer on each opposite side of said intermediate layer so as to form an exposed border having a configuration at least substantially surrounding the limited surface area on each opposite side of said intermediate layer.