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. 18, 2000
Filed:
Dec. 11, 1998
Steven L Haehn, Colorado Springs, CO (US);
James P Yakura, Colorado Springs, CO (US);
LSI Logic Corporation, Milpitas, CA (US);
Abstract
A method of screening EEPROMs for data retention quality employs a UV source which is arranged to be impinged upon the devices while in wafer form, at or near an electrical probe station. Known data is stored in memory cells on an EEPROM chip while the chip is in wafer form, at a probe station. The wafer is then moved beneath a UV silo near the probe station and exposed to UV light, for a period of time and at an intensity which is sufficient to cause leakage of charge from potentially leaky floating gates. The wafer is again subjected to electrical probe where the amount of change in retained charge is detected. From this test, an indication of the charge retention ability of the devices is obtained. The UV light increases the energy state of the stored charge thus accelerating the decay of the stored charge located on the floating gates in the EEPROM device. Bits that have inherent leakage paths decay more rapidly.