Method and apparatus for diagnosing broken scan chain based on leakage light emission
US7426448B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 2004 |
| Grant date | Sep 16, 2008 |
| Priority date | — |
| Expiry date | Mar 17, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/311
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A mechanism for diagnosing broken scan chains based on leakage light emission is provided. An image capture mechanism detects light emission from leakage current in complementary metal oxide semiconductor (CMOS) devices. The diagnosis mechanism identifies devices with unexpected light emission. An unexpected amount of light emission may indicate that a transistor is turned off when it should be turned on or vice versa. All possible inputs may be tested to determine whether a problem exists with transistors in latches or with transistors in clock buffers. Broken points in the scan chain may then be determined based on the locations of unexpected light emission.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.