The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 17, 2002
Filed:
Feb. 08, 2000
Kenneth R. Wilsher, Palo Alto, CA (US);
William K. Lo, San Jose, CA (US);
Schlumberger Technologies, Inc., San Jose, CA (US);
Abstract
Optical interferometery is used to probe an integrated circuit device under test (DUT). During each cycle of a repetitive electrical test pattern applied to the DUT a reference pulse is provided at a fixed time relative to the test pattern, and a probe pulse is provided at a time scanned through the test pattern in the manner of equivalent time sampling. The probe and reference light pulses are each split to provide at least a second probe pulse and a second reference pulse. One probe pulse and one reference pulse interact with the DUT at the same physical location, but at displaced times with respect to each other. The second probe pulse and the second reference pulse travel an optical delay path with length controlled to compensate for motions of the DUT. The probe pulses are recombined and detected to provide a probe interference signal. The reference pulses are recombined and detected to provide a reference interference signal. For each cycle, electrical activity in the DUT is detected by preparing a ratio of the probe interference signal and the reference interference signal.