High-thermal conductivity circuit board
First Claim
1. A circuit board comprising:
- a base layer having first and second opposing surfaces, said base layer provided from a first material having a relatively high thermal conductivity and a coefficient of thermal expansion relatively close to the thermal coefficient of expansion of silicon;
a metal skin layer disposed over each of the first and second opposing surfaces of said base layer, said metal skin layer provided from a second different material which is anodizeable;
an oxide layer having a first surface in contact with said metal skin layer and a having a second surface, the second surface having a plurality of pores formed therein;
a sealant layer having a first surface disposed over the second surface of said oxide layer and a second surface, said sealant layer provided from a thermoplastic resin having an electrically insulative characteristic and having a heat conduction characteristic, and wherein the thermoplastic resin of said sealant layer is disposed to fill the plurality of pores in the oxide layer; and
a metal foil having a first surface disposed over and in contact with the second surface of said sealant layer and having a second opposing surface.
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Accused Products
Abstract
A thermally efficient circuit board has a base layer with high thermal conductivity and a thermal expansion coefficient close to that of silicon, such as aluminum silicon carbide. Above the base layer is a layer of anodized metal, either a separate material, such as aluminum, which is formed on the base and then anodized, or an anodized portion of the base itself. To the anodized metal is then applied a sealant material of lower thermal conductivity, but good electrically insulative and adhesive qualities, such as Teflon FEP. The sealant flows into cavities in the porous anodized metal structure, creating a well-anchored bond. A metal foil layer is then bonded to the surface of the sealant, and used to pattern conductive circuit paths using conventional methods.
40 Citations
22 Claims
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1. A circuit board comprising:
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a base layer having first and second opposing surfaces, said base layer provided from a first material having a relatively high thermal conductivity and a coefficient of thermal expansion relatively close to the thermal coefficient of expansion of silicon; a metal skin layer disposed over each of the first and second opposing surfaces of said base layer, said metal skin layer provided from a second different material which is anodizeable; an oxide layer having a first surface in contact with said metal skin layer and a having a second surface, the second surface having a plurality of pores formed therein; a sealant layer having a first surface disposed over the second surface of said oxide layer and a second surface, said sealant layer provided from a thermoplastic resin having an electrically insulative characteristic and having a heat conduction characteristic, and wherein the thermoplastic resin of said sealant layer is disposed to fill the plurality of pores in the oxide layer; and a metal foil having a first surface disposed over and in contact with the second surface of said sealant layer and having a second opposing surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A circuit board comprising:
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a base layer of aluminum silicon carbide having first and second opposing surfaces; a layer of anodized aluminum having a first surface disposed against the first surface of said base layer and having a second porous surface; a thermoplastic resin embedded in substantially all of the interstitial regions of the porous surface of said anodized aluminum; and a layer of electrically conductive material in contact with said thermoplastic resin.
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12. A method of fabricating a circuit board comprising:
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(a) providing a base layer of material having relatively high thermal conductivity; (b) anodizing the first surface of said base layer to provide a layer of oxide having a porous surface and having a thickness typically of about 0.002 inch; (c) disposing a thermoplastic resin over the porous surface of the oxide layer; (d) heating the thermoplastic resin to a temperature corresponding to a melting temperature of the thermoplastic resin such that the thermoplastic resin changes to a liquid state; and (e) forcing the thermoplastic resin into substantially all of the pores of the oxide layer while the thermoplastic resin is in a liquid state. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification