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Contactless Infrared Laser PROBE Circuit Analyzer

IP.com Disclosure Number: IPCOM000039465D
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Hwang, TT: AUTHOR

Abstract

The system described uses a focussed spot of infrared (IR) laser light impinged on the back surface of a semiconductor device of an integrated circuit to induce a photocurrent which can be used to analyze the conductive state of the device in the associated circuit. The light- spot location is observed by means of an IR microscope. Because the observation is made from the back surface, there is no interference by surface layers which has inhibited systems using visible light and observations on the front surface. It is well known [1,2] that by shining light on portions of semiconductor devices and inducing photocurrents the conducting or non- conducting state of the device can be observed.

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Contactless Infrared Laser PROBE Circuit Analyzer

The system described uses a focussed spot of infrared (IR) laser light impinged on the back surface of a semiconductor device of an integrated circuit to induce a photocurrent which can be used to analyze the conductive state of the device in the associated circuit.

The light- spot location is observed by means of an IR microscope. Because the observation is made from the back surface, there is no interference by surface layers which has inhibited systems using visible light and observations on the front surface. It is well known [1,2] that by shining light on portions of semiconductor devices and inducing photocurrents the conducting or non- conducting state of the device can be observed. The key element in the present system is the use of IR laser light which can pass through the back of the semiconductor body to the device on the opposite surface. An IR microscope permits observation of the IR spot location with respect to the semiconductor device geometry. The state of the device being probed by the beam is measured by its response to the induced photocurrents. References Product specification brochure, "DATA PROBE Model 2010

IC Logic Laser Analyzer," by Mitsui & Co. (USA), Inc.

M. T. Pronobis and D. J. Burns, "Laser Die Probing for

Complex CMOS," Proceedings of the 1982 ISTFA, 178-181

(October 1982).

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