Texas Instruments Corporation

Premkumar R Hingorany

Henry F Breit

John A Haug

James A Forster

Steven E Levy

Juan M Alvarez

Ceramic to metal stock or substrates having a relatively large and thick metal core and a relatively thin ceramic layer or layers are bonded to the metal core or a selected portion thereof by providing a metal core material having a temperature coefficient of expansion which is tailored to the temperature coefficient of expansion of the ceramic layer to be bonded thereto. The typical core materials include multilayer composite metal laminates embodying Cu/Mo/Cu, Cu/Kovar/Cu, Cu/Invar/Cu and the like and including powdered metal composites embodying Cu-W, Ag-Mo, Ag-W, Al-Si, Cu/Mo/Cu, Cu/Kovar/Cu, SiC-Cu, Ni-Fe alloys having from about 20% Ni to about 80% Ni, etc. The ceramic layer is chosen primarily for the properties of dielectric strength and isolation properties and typically include such ceramics as alumina, beryllium oxide, aluminum nitride, silicon carbide, etc. Where the core composite includes copper outer surface materials or is plated to have copper outer surface materials, the core and ceramic materials and particularly multiple sections of the ceramic materials are provided in spaced relation on the metal cores of relatively large area and are preferably bonded to the core using a copper oxide eutectic formed on the core surface.

Clad metal substrate

A method of forming enclosures for microwave and hybrid devices and the enclosure itself wherein the metals to be joined are thin (i.e., less than 40 mils thick) and/or thick (up to several inches) and wherein metallurgical hermetic bonds are provided between adjacent metals which are generally difficult to bond to each other and may be bonded by a select number of bonding processes.

Hybrid/microwave enclosures and method of making same

A heat dissipating pad or support member for mounting a semiconductor device in an electrical circuit has a metal core with a relatively low coefficient of thermal expansion preferably lower than that of the semiconductor device and has a thermally conducting, corrosion resistant metal coating with relatively greater thermal conductivity than the core. The thermally conducting coating is metallurgically bonded to top, bottom and two lateral surfaces of the core with a selected thickness to cooperate with the core in providing an outer surface portion of the member over the top of the core having an effective coefficient of thermal expansion substantially corresponding to the semiconductor device to reliably mount the semiconductor device thereon. The coating is thicker on at least one of the two lateral core surfaces so that heat collected from the semiconductor device at the top surface of the thermally conducting coating is efficiently transferrred via the lateral surface or surfaces on the core to the portion of the thermally conducting coating on the bottom surface of the member.

Heat dissipating member for mounting a semiconductor device and

An improved surface mounted system for leaded semiconductor devices has J-shaped device leads soldered to respective portions of circuit pads on a printed circuit board, each lead having inner and outer surfaces of the J-shape covered with solder dewetting and solder wetting metals respectively which are metallurgically bonded to a metal core of the lead formed of a springy, relatively high electrical conductivity metal. The short leg of each J-shaped lead is curved and the outer, solder wettable surface of that curved lead part is soldered to a selected circuit pad portion, preferably by use of a pad or solder paste deposited on the circuit pad portion, while other surfaces of the lead are maintained substantially free of solder for avoiding solder bridging between leads and for assuring that an adequate amount of solder is retained between the curved lead part and the desired circuit pad portion to provide secure electrical connection to the printed circuit and secure surface mounting of the device on the circuit board.

Growing community of inventors

Louisville, CO, United States of America

Premkumar R Hingorany