Method for determining lead frame failure modes using acoustic emission and discriminant analysis techniques
US4417478A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 1981 |
| Grant date | Nov 29, 1983 |
| Priority date | — |
| Expiry date | Nov 30, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N29/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An automatic pull tester and an acoustic emission system are herein combined to analyze the failure modes of lead frames bonded to integrated circuits. By using a discriminant analysis technique, a specific failure mode can be determined in real-time by first measuring up to five variables during the pulling operation. The five variables that may be measured comprise acoustic emission signals of a first amplitude (AE1), acoustic emission signals of a second amplitude (AE2), the time elapsed until failure (.DELTA.t), the number (n) of acoustic emission bursts above a first threshold, to the peak pulling force at failure (L.sub.max). Next, the variables measured are incorporated into a plurality of predetermined functions, each function corresponding to one failure mode (FM1 to FM5). The failure mode of the bond is determined by selecting the function having the highest value (FIG. 4).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.