Jonathan G Levi

US Patent:

52142990, May 25, 1993

Filed:

Sep 22, 1989

Appl. No.:

7/411434

Inventors:

Laszlo V. Gal - Poway CA
David W. Waite - Carlsbad CA
Jonathan A. Levi - Fallbrook CA

Assignee:

Unisys Corporation - Blue Bell PA

International Classification:

H01L 2702

US Classification:

257208

Abstract:

An improved standard cell logic chip, of the type which contains one to fifteen thousand standard logic cells that are disposed in rows on a substrate, and has cell interconnect channels of different widths between the rows, also includes fast change logic cells which are sparsely distributed in the rows of standard logic cells. Each fast change cell selectively performs any one of several logic functions. These fast change logic cells are formed from the same stacked conductive and insulative layers as the standard logic cells; however, in the fast change cells, all conductive and insulative layers which are below at least the mid level in the stack of layers have respective patterns which are identical in every fast change cell. Only the remaining conductive and insulative layers in the fast change cells have respective patterns which differ from one fast change cell to another, and they select the logical functions which the fast change cells perform.

US Patent:

52668908, Nov 30, 1993

Filed:

Jun 26, 1992

Appl. No.:

7/905596

Inventors:

Cevat Kumbasar - Carlsbad CA
Jonathan A. Levi - Fallbrook CA
Richard J. Petschauer - Edina MN
Roy R. Shanks - San Diego CA
Steven S. Wei - San Diego CA

Assignee:

Unisys Corporation - Blue Bell PA

International Classification:

G01R 3100

US Classification:

324158R

Abstract:

An integrated circuit test wafer quickly detects A-C defects in any process by which the wafer is fabricated. This test wafer includes a semiconductor substrate having a major surface, and a diagnostic circuit that is repeatedly integrated over most of the wafer's surface. Each diagnostic circuit includes: a) a plurality of ring oscillators which generate respective cyclic output signals; b) an addressing circuit that receives external input signals and in response selects an output signal from any particular ring oscillator of the plurality; c) a timing circuit that generates a timing signal with a certain time period; and, d) a counting circuit that counts the number of cycles that occur in the selected output signal during the time period and provides that number as an output. By comparing the relative or absolute speeds of all of the ring oscillators, a ring oscillator with an A-C defect is detected; and, a defective ring oscillator can then be analyzed under an E-beam microscope to determine the defects cause. Preferably, the ring oscillators occupy at least 90% of the test wafers surface so that A-C defects are detected even when they are sparsely distributed on the test wafer.

Author:

Jonathan Levi

ISBN #:

0679408932

Author:

Jonathan Levi

ISBN #:

0679739696

Author:

Jonathan Levi

ISBN #:

2855981298