Westinghouse Electric Corporation

Soong H Lee

Dale E Dawson

Daniel C Buck

Lawrence E Dickens

James E Degenford

Scott A Imhoff

Gary F Shade

Chun L Lau

Anthony L Conti

A semiconductor device has material removed from the back of the substrate and a manufacturing process is provided for manufacturing these devices. In the exemplary embodiment, a GaAs FET chip is formed by a process including the step of etching the GaAs substrate from the back of the chip in a defined removal region to reduce the dielectric constant in the region of the source-to-drain path. A buffer layer of differing material provided between the active layers and the substrate prevents etching of the active layers during the removal process. To allow simplified etching patterns, the source-to-drain path may be laid out on the surface of the chip in a variety of patterns, including 'packed' patterns concentrating a large path area in a small surface area of the chip. Optionally, this buffer layer may also be etched away in a further processing step. An insulating layer of material may be added to the back side of the chip in the etched region to increase structural strength, and a pressure relief ventilation path may be provided connecting the removal region to the outside at an edge or at the surface of the chip.

Low-loss semiconductor device and backside etching method for

The invention is an improved integrated circuit chip assembly which provides enhanced heat transfer from active electronic devices of the integrated circuit by significantly reducing the thickness of the substrate and providing the necessary structural support through a thermally conducting spacing segment between the substrate and a ground plane in the region of the active electronic devices. This improvement further permits added flexibility in the design of transmission lines by permitting adjustment of the distance between the transmission line and the ground plane and furthermore by permitting the introduction of a second dielectric material such that the impedance of the transmission line may be controlled.

Integrated circuit chip assembly utilizing selective backside deposition

A reflective hybrid analog phase shifter is detailed which is operable in the X-band, and which exhibits minimal phase shift variation with higher power loadings. A pair of back-to-back connected Schottky varactor diodes are serially connected to each of the phase shifting ports of a 3 dB coupler. The Scottky varactor diodes are reverse biased to permit continuous variation of the phase shift as a function of analog bias potential. A monolithically fabricated implementation of this circuit design is detailed.

Wide band microwave analog phase shifter

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Potomac, MD, United States of America

Soong H Lee