High-thermal conductivity circuit board
AssigneeHeat Technology, Inc.
InventorRalph I. Larson
Life of this patent
Estimating the term…
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.
Claims22
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.
A circuit board comprising:
- 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.
A method of fabricating a circuit board comprising:
- (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.
Dependencies are inferred from the claim text.