Thermally conductive, electrically insulative laminate

• US 4,810,563 A
• Filed: 10/30/1987
• Issued: 03/07/1989
• Est. Priority Date: 03/14/1986
• Status: Expired due to Term

• Current Assignee: Berquist Company The (Henkel AG & Co KGaA)
• Original Assignee: Berquist Company The (Henkel AG & Co KGaA)
• Inventors: Juenger, Bruce H., Fick, Herbert J., DeGree, David C.
• Primary Examiner(s): LUSIGNAN, MICHAEL R
• Application Number:
  US07/114,855
• Time in Patent Office: 494 Days
• Field of Search: 165/185, 174/16 HS, 174/138 G, 174/68.5, 361/386, 361/387, 361/388, 361/389, 361/403, 428/328, 428/329, 428/339, 428/209, 428/458, 428/901
• US Class Current: 428/209
• CPC Class Codes: B32B 15/08 of synthetic resin
• CPC Class Codes: B32B 15/088 comprising polyamides
• CPC Class Codes: B32B 15/18 comprising iron or steel B32B15/011, B32B15/012 and B32B15/013 take precedence
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 2255/06 on metal layer
• CPC Class Codes: B32B 2255/205 Metallic coating
• CPC Class Codes: B32B 2305/30 Fillers, e.g. particles, powders, beads, flakes, spheres, chips
• CPC Class Codes: B32B 2307/102 Insulating
• CPC Class Codes: B32B 2307/302 Conductive
• CPC Class Codes: B32B 2311/12 Copper
• CPC Class Codes: B32B 2377/00 Polyamides
• CPC Class Codes: B32B 2379/08 Polyimides
• CPC Class Codes: B32B 2405/00 Adhesive articles, e.g. adhesive tapes
• CPC Class Codes: B32B 2457/08 PCBs, i.e. printed circuit boards
• CPC Class Codes: B32B 7/14 applied in spaced arrangements, e.g. in stripes
• CPC Class Codes: H05K 1/0346 containing N
• CPC Class Codes: H05K 1/0373 containing additives, e.g. fillers H05K1/036 takes precedence
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 1/056 the metal substrate being covered by an organic insulating layer
• CPC Class Codes: H05K 2201/0154 Polyimide
• CPC Class Codes: H05K 2201/0209 : Inorganic, non-metallic particles
• CPC Class Codes: H05K 2201/0355 : Metal foils
• CPC Class Codes: H05K 2201/068 : wherein the coefficient of thermal expansion is important
• CPC Class Codes: H05K 3/244 : Finish plating of conductors, especially of copper conductors, e.g. for pads or lands selective plating methods H05K3/243; finish plating of conductors made by printing techniques H05K3/246; solder as finish H05K3/3457, e.g. by plating H05K3/3473
• CPC Class Codes: H05K 3/384 : by plating
• CPC Class Codes: H05K 3/386 : by the use of an organic polymeric bonding layer, e.g. adhesive
• CPC Class Codes: Y10S 428/901 : Printed circuit
• CPC Class Codes: Y10T 428/24917 : including metal layer
• CPC Class Codes: Y10T 428/256 : Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/257 : Iron oxide or aluminum oxide
• CPC Class Codes: Y10T 428/269 : including synthetic resin or polymer layer or component
• CPC Class Codes: Y10T 428/31681 : Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]

Abstract

A thermally conductive laminate structure for use as a mounting base and/or chassis attachment member in combination with solid-state electronic devices, the laminate preferably comprising up to five layers including a pair of outer metallic layers disposed on opposite sides of center composite layers of electrically insulative layers separated by an interposed metallic layer. The center insulative layers are films of polyimide(amide) material, with the polyimide(amide) film being filled with a quantity of aluminum oxide, boron nitride, or other suitable particulate solid in an amount ranging from between about 30% and 100% by weight of polyimide(amide) solids. The outer layers are metallic, with the base member being a metallic pad of copper or aluminum, and with the opposed metallic layer being copper and arranged in a printed circuitry pattern or array.

Claims

1. Base means for mounting semiconductor devices onto a heat dissipating thermally conductive support and comprising:

(a) a base substrate means comprising a sheet of at least one layer of a thermally conductive metal selected from the group consisting of copper, aluminum, steel, Alloy 42, Invar, Kovar and molybdenum and laminates thereof, and with said base substrate having a cross-sectional thickness in excess of about 15 mils;

(b) an imperforate polyimide(amide) film bonded with a first layer of adhesive to the upper surface of said base substrate, said film and said adhesive layer each containing a thermally conductive electrically insulative particulate solid therein selected from the group consisting of aluminum oxide, boron nitride, silic, beryllium oxide, magnesium oxide, titanium dioxide, aluminum nitride, silicon carbide, zinc oxide, diamond and silicon nitride in an amount from between 20% and 200% by weight of polyimide(amide) solids and adhesive solids respectively, and with the polyimide(amide) film having a thickness of between about one-quarter mil and 5 mils; and

(c) electrically conductive circuitry secured to the upper surface of said polyimide(amide) film with a second layer of adhesive, said first and second adhesive layers having a thickness in excess of about one-quarter mil and having means arranged along the outer surface of said electrically conductive circuitry and along the exposed surface of said second layer of adhesive to mountingly receive and support the underside surface of a semiconductor device in heat dissipating relationship with said thermally conductive support.

2. The base means as defined in claim 1 being particularly characterized in that said electrically conductive circuitry is adhesively bonded to the upper surface of said polyimide(amide) film, and with said adhesive layer being selected from the group consisting of acrylic resin adhesives and epoxy resin adhesives.

3. The base means as defined in claim 1 being particularly characterized in that said electrically conductive circuitry is adhesively bonded to the upper surface of said polyimide(amide) film, and with said adhesive layer being an epoxy resin adhesive and having a thickness of between about one-half mil and two mils.

4. The base means as defined in claim 1 being particularly characterized in that said electrically conductive circuitry comprises a sheet of copper having a flash coating of nickel thereon, and wherein said layer of adhesive is bonded to the nickel surface of said base substrate.

5. The base means as defined in claim 1 being particularly characterized in that said base substrate comprises a multi-layer laminate including a center layer of an iron-nickel alloy containing between 40% and 50% by weight of nickel, balance iron, with a metal dissimilar to the said center layer disposed on opposite surfaces of said center layer.

6. The base means as defined in claim 1 being particularly characterized in that said base substrate comprises a multi-layer laminate wherein at least one of said layers comprises a sintered mixture of iron and nickel containing between about 40% and 50% by weight of nickel, balance iron.

7. The base means as defined in claim 1 being particularly characterized in that said base substrate comprises a multi-layer laminate including a center layer of molybdenum, with a metal dissimilar to molybdenum disposed on opposite surfaces of said center layer.

8. The base means as defined in claim 1 being particularly characterized in that said base substrate comprises a layer of molybdenum.

9. The base means as defined in claim 1 being particularly characterized in that said base substrate comprises a layer of Invar.

10. The base means as defined in claim 1 being particularly characterized in that said base substrate and said electrically conductive circuitry comprise electro-deposited copper having a flash coating of nickel thereon, and wherein a polymeric layer is bonded to the nickel surface of each of said base substrate and said electrically conductive circuitry.

11. The base means as defined in claim 1 being particularly characterized in that said electrically conductive circuitry comprises aluminum-clad copper.

12. The base means as defined in claim 1 being particularly characterized in that said electrically conductive circuitry comprises copper having a film of solder on the outer surface thereof.

13. The base means as defined in claim 1 being particularly characterized in that said base substrate comprises rolled copper.

14. The base means as defined in claim 1 being particularly characterized in that said base substrate comprises a multi-layer laminate, and wherein said laminate comprises at least one layer of rolled copper.

15. The base means as defined in claim 1 being particularly characterized in that said base substrate comprises a layer of electro-deposited copper having a thickness greater than one mil with a nickel flash coating on the outer surface thereof.

16. The base means as defined in claim 1 being particularly characterized in that each of said first and second adhesive layers consist of at least two discrete imperforate film layers of epoxy base resin.

17. Base means for mounting semiconductor devices onto a heat dissipating thermally conductive support and comprising:

(a) a base substrate means comprising a sheet of at least one layer of a thermally conductive metal selected from the group consisting of copper, aluminum, steel, Alloy 42, Invar, Kovar and molybdenum and laminates thereof, and with said base substrate having a cross-sectional thickness in excess of about 15 mils and arranged along one surface of said base means;

(b) electrically conductive circuitry arranged in oppositely disposed relationship to said base substrate means and having a thickness in excess of about one-quarter mil and having means arranged on the outer surface thereof to mountingly receive and support a semiconductor device in heat dissipating relationship thereon;

(c) heat spreader means comprising a highly thermally conductive metallic layer selected from the group consisting of aluminum and copper and being interposed between said base substrate and said electrically conductive circuitry;

(d) a pair of imperforate polyimide(amide) films, one interposed between said heat spreader means and said base substrate means and one interposed between said heat spreader means and said electrically conductive circuitry;

(e) a substantially continuous void-free adhesive film bonding adjacent members of said base means together, one to another, each of said imperforate polyimide(amide) films and said adhesive layers each containing a thermally conductive electrically insulative particulate solid therein selected from the group consisting of aluminum oxide, boron nitride, silica, beryllium oxide, magnesium oxide, titanium dioxide, aluminum nitride, silicon carbide, zinc oxide, and silicon nitride in an amount from between 20% and 200% by weight of polyimide(amide) solids and adhesive solids respectively, and with the polyimide(amide) film having a thickness in excess of about one-quarter mil.

18. The base means as defined in claim 17 being particularly characterized in that said adhesive films comprise an epoxy resin selected from the group consisting of phenolic and bisphenol-A epoxies.

19. The base means as defined in claim 17 being particularly characterized in that said thermally conductive, electrically insulative particulate solid is selected from the group consisting of aluminum oxide, aluminum nitride, boron nitride and mixtures thereof.

20. The base means as defined in claim 17 being particularly characterized in that each of said adhesive films has a cross-sectional thickness of greater than one-half mil.

21. The base means as defined in claim 17 being particularly characterized in that said base substrate means comprises a sheet of copper having a flash coating of nickel thereon, and wherein said layer of adhesive is bonded to the nickel surface of said base substrate.

22. The base means as defined in claim 17 being particularly characterized in that said base substrate comprises a multi-layer laminate including a center layer of an iron-nickel alloy containing between 40% and 50% by weight of nickel, balance iron, with a metal dissimilar to the said center layer disposed on opposite surfaces of said center layer.

23. The base means as defined in claim 17 being particularly characterized in that said base substrate comprises a multi-layer laminate wherein at least one of said layers comprises a sintered mixture of iron and nickel containing between about 40% and 50% by weight of nickel, balance iron.

24. The base means as defined in claim 17 being particularly characterized in that said base substrate comprises a multi-layer laminate including a center layer of molybdenum, with a metal dissimilar to molybdenum disposed on opposite surfaces of said center layer.

25. The base means as defined in claim 17 being particularly characterized in that said base substrate comprises a layer of molybdenum.

26. The base means as defined in claim 17 being particularly characterized in that said base substrate comprises a layer of Invar.

27. Base means for mounting semiconductor devices onto a heat dissipating thermally conductive support and comprising:

(a) a base substrate means comprising a sheet of at least one layer of a thermally conductive metal selected from the group consisting of copper, aluminum, steel, Alloy 42, Invar, Kovar and molybdenum and laminates thereof, and with said base substrate having a cross-sectional thickness in excess of about 15 mils and arranged along one surface of said base means;

(b) electrically conductive circuitry arranged in oppositely disposed relationship to said base substrate means and having a thickness in excess of about one-quarter mil and having means arranged on the outer surface thereof to mountingly receive and support a semiconductor device in heat dissipating relationship thereon;

(c) means comprising highly thermally conductive layers interposed between said substrate and said electrically conductive circuitry, said means comprising at least two imperforate layers interposed therebetween;

(d) a substantially continuous void-free epoxy resin adhesive film bonding adjacent members of said base means together, one to another, each of said imperforate films and said adhesive layers each containing a thermally conductive electrically insulative particulate solid therein selected from the group consisting of aluminum oxide, boron nitride, silica, beryllium oxide, magnesium oxide, titanium dioxide, aluminum nitride, silicon carbide, zinc oxide, and silicon nitride in an amount from between 20% and 200% by weight of imperforate solids and adhesive solids respectively, and with the imperforate film consisting essentially of an epoxy resin and having a thickness in excess of about one-quarter mil.

28. Base means for mounting semiconductor devices onto a heat dissipating thermally conductive support and comprising:

(a) a base substrate means comprising a sheet of at least one layer of a thermally conductive metal slelected from the group consisting of copper, aluminum, steel, Alloy 42, Invar Kovar and molybdenum and laminates thereof, and with said base substrate having a cross-sectional thickness in excess of about 15 mils and arranged along one surface of said base means;

(b) electrically conductive circuitry arranged in oppositely disposed relationship to said base substrate means and having a thickness in excess of about one-quarter mil and having means arranged along and adjacent the outer surface of said circuitry to mountingly receive and support the undersurface of a semiconductor device in heat dissipating relationship thereon;

(c) heat spreader means comprising a highly thermally conductive metallic layer selected from the group consisting of aluminum and copper and being interposed between said substrate and said electrically conductive circuitry;

(d) a pair of imperforate films, one interposed between said heat spreader means and said base substrate means and one interposed between said heat spreader means and said electrically conductive circuitry;

(e) a substantially continuous void-free epoxy resin adhesive film bonding adjacent members of said base means together, one to another, each of said imperforate films and said adhesive layers each containing a thermally conductive electrically insulative particulate solid therein selected from the group consisting of aluminum oxide, boron nitride, silica, beryllium oxide, magnesium oxide, titanium dioxide, aluminum nitride, silicon carbide, zinc oxide, and silicon nitride in an amount from between 20% and ®

% by weight of imperforate solids and adhesive solids respectively, and with the imperforate film having a thickness in excess of about one-quarter mil.

29. The base means as defined in claim 28 being particularly characterized in that said electrically conductive circuitry is adhesively bonded to the upper surface of said imperforate film disposed between said heat spreader means and said electrically conductive circuitry and with said epoxy adhesive layer having a thickness less than about two mils.

30. The base means as defined in claim 28 being particularly characterized in that said adhesive films comprise an epoxy resin selected from the group consisting of phenolic and bisphenol-A epoxies.

31. The base means as defined in claim 28 being particularly characterized in that said electrically conductive circuitry comprises aluminum-clad copper with a nickel flash coating thereon.

32. The base means as defined in claim 28 being particularly characterized in that said electrically conductive circuitry comprises copper having a thickness of at least seven mils.

33. The base means as defined in claim 28 being particularly characterized in that said base substrate comprises electro-deposited copper having a nickel flash coating on the outer surface thereof.

34. The base means as defined in claim 28 being particularly characterized in that each adhesive film bonding adjacent members of said base means together comprises a pair of independent discrete adhesive film layers bonded together to form said substantially continuous void-free adhesive film.