The Bergquist Company

G. T. Schjeldahl Company

Herbert J Fick

David C DeGree

Bruce H Juenger

Edward J Mahagnoul

Withdrawal and dissipation of heat from an electronic solid-state device by an associated heat-sink structure are promoted by a relatively thin broad-area dielectric interfacing composed of dual filled layers of compliant silicone rubber in sandwiching relation to a porous glass-cloth carrier, one of the layers being pre-vulcanized and the other being subsequently cured and bonded in place once the composite interfacing has been applied to heat-sink surfaces adapted for abutment with the device for the intended heat transfer. The soft rubber interfacing offers good dielectric and insulating and voltage-breakdown characteristics even when well loaded with thermally-conductive oxides, and intimate voidless surface contacts and high-quality thermal matching are fostered both along abutting compliant surfaces of the pre-cured portion of the interfacing and along fully bonded surfaces of the portion cured in situ. Processing which makes such interfacing eminently practical and particularly advantageous to the user includes initial application of filled uncured rubber to one side of the sheet of the porous carrier, followed by its vulcanization and then by application of a further uncured amount to the opposite side of the carrier, with a protective peel-off plastic covering being used to facilitate handling and release-cutting of desired smaller wafer configurations from the large-area composite; uncured sides of the smaller peeled wafers are than mated with appropriate parts of heat sinks and cured, thereby producing heat sinks integrated with securely-bonded thermally-matching dielectric interfacing in readiness for unions with devices from which heat must be dissipated efficiently.

Interfacing for heat sinks

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.

Thermally conductive, electrically insulative laminate

A relatively thin broad-area dielectric interfacing composed of dual filled layers of compliant silicone rubber in sandwiching relation to a porous glass-cloth carrier, one of the layers being pre-vulcanized and the other being subsequently cured and bonded in place once the composite interfacing has been applied to heat-sink surfaces adapted for abutment with the device for the intended heat transfer. The soft rubber interfacing offers good dielectric and insulating and voltage-breakdown characteristics even when well loaded with thermally-conductive oxides, and intimate voidless surface contacts and high-quality thermal matching are fostered both along abutting compliant surfaces of the pre-cured portion of the interfacing and along fully bonded surfaces of the portion cured in situ. Processing which makes such interfacing eminently practical and particularly advantageous to the user includes initial application of filled uncured rubber to one side of a sheet of the porous carrier, followed by its vulcanization and then by application of a further uncured amount to the opposite side of the carrier. A protective peel-off plastic covering is used to facilitate handling and release-cutting of desired smaller wafer configurations from the large area composite. Uncured sides of the smaller peeled wafers are then mated with appropriate parts of heat sinks and cured.

Method of preparing interfacings of heat sinks with electrical devices

A relatively thin broad-area dielectric interfacing composed of dual filled layers of compliant silicone rubber in sandwiching relation to a porous glass-cloth carrier, one of the layers being pre-vulcanized and the other being subsequently cured and bonded in place once the composite interfacing has been applied to heat-sink surfaces adapted for abutment with the device for the intended heat transfer. The soft rubber interfacing offers good dielectric and insulating and voltage-breakdown characteristics even when well loaded with thermally-conductive oxides, and intimate voidless surface contacts and high-quality thermal matching are fostered both along abutting compliant surfaces of the pre-cured portion of the interfacing and along fully bonded surfaces of the portion cured in situ. Processing which makes such interfacing eminently practical and particularly advantageous to the user includes initial application of filled uncured rubber to one side of a sheet of the porous carrier, followed by its vulcanization and then by application of a further uncured amount to the opposite side of the carrier. A protective peel-off plastic covering is used to facilitate handling and release-cutting of desired smaller wafer configurations from the large-area composite. Uncured sides of the smaller peeled wafers are then mated with appropriate parts of heat sinks and cured.

Interfacing of heat sinks with electrical devices, and the like

A thermally conductive electrically insulative laminate for use as chassis barriers in combination with solid-state electronic devices, the laminate comprising at least three layers and including a pair of outer layers disposed on opposite sides of a center layer. The center layer comprises a film of a polyimide (amide) filled with a quantity of either aluminum oxide or boron nitride particulate solids and included in an amount ranging from between about 10% to about 50% by volume. The outer layers consist essentially of silicone base rubber, and are preferably filled with a quantity of aluminum oxide or boron nitride particulate solids in an amount ranging from between about 25% and 50% by volume.

Mounting pad for solid-state devices

A mechanically sound electrically stable substrate for use in an electrical laminate wherein the substrate supports at least one electrically conductive metallic layer. The substrate portion comprises a woven glass cloth base pad which is interposed between a pair of outer substrate layers of a polyester mat. The polyester mat comprises a mat of spunbonded continuous filament polyester fibers, preferably polyethylene terephthalate fibers, calendered, with the fibers including a mixture of bulk fibers of relatively high melting point retained in place or bonded by a binder fiber of essentially the same polyester material but with a relatively lower melting point. In fabrication, the mat, along with the glass cloth, is saturated with a curable resin, for example a heat curable resin, preferably polybutadiene, which is cured in-situ.

Growing community of inventors

Northfield, MN, United States of America

Herbert J Fick