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:
Jul. 22, 1997
Filed:
Sep. 18, 1995
Koji Eriguchi, Osaka, JP;
Yukiharu Uraoka, Nara, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A plurality of different constant currents are implanted into an element of a semiconductor device such as a gate oxide film and a metal wire, a charge-to-breakdown (or a breakdown time) is measured from a result of current implantation, a relationship between a constant current value and the charge-to-breakdown (or a breakdown time) is determined, and a time-sequence change in the current during application of a constant voltage is presumed. Next, of a time-sequence change characteristic of the current during application of the constant voltage, current values during the respective minute periods are approximated to a constant current value. Consumption ratios of the life time due to the respective current values are calculated based on a relationship between the constant current value and the charge-to-breakdown (or a breakdown time). the consumption ratios of the life time are accumulated, and the sum of the respective minute periods which is obtained when the accumulation value becomes 1 is presumed to be the life time. Since the life time during application of the constant voltage is presumed utilizing a result of a constant current test which takes only a short time, it is possible to quantitatively, quickly and accurately presume the reliability life time of a gate oxide film and a metal wire and a TFT, etc.