Test system for VLSI digital circuit and method of testing
US4588950A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 15, 1983 |
| Grant date | May 13, 1986 |
| Priority date | — |
| Expiry date | Nov 15, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/308
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The conductive state of a transistor in a semiconductor integrated circuit is determined by irradiating the transistor with a radiation beam and measuring changes in load current, thereby indicating whether the transistor was conducting or non-conducting prior to irradiation. A correlated double sampling method is employed in measuring changes in load current. A load resistor in series with the device under test is capacitively coupled to a differential amplification means including a plurality of differential amplifiers with buffers connected between successive amplifiers. A system clock is stopped at a predetermined time period prior to irradiating the transistor. A bypass switch shunts the load resistor until the clock is stopped.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.