Test cost is a critical component in the overall cost of the product. Test cost varies in direct proportion with test time. This thesis introduces a data driven feed forward adaptive technique for reducing test time at wafer sort while maintaining the product defect level. Test data from first insertion of wafer is statistically analyzed to make a decision about adaptive test flow at subsequent insertions.
The data driven feed forward technique uses a statistical screen to analyze test data from first probe of wafer and provides recommendations for test elimination at second insertions. At the second insertion dies are subjected to only the optimum number of tests for a reduced test flow. This technique is applicable only for the products which are tested at two or more insertions.
The statistical screen identifies the dies for reduced test flow based upon correlation of tests across insertions. The tests which are repeated at both the insertions and are highly correlated are the candidates of elimination at second insertion.
The feed forward technique is applied to a mixed signal analog product and figures of merit are evaluated. Application of technique to the production data shows that there is an average 55% test time reduction when a single site is tested per touchdown and up to 10% when 16 sites are tested in parallel per touchdown.
| Identifer | oai:union.ndltd.org:pdx.edu/oai:pdxscholar.library.pdx.edu:open_access_etds-2048 |
| Date | 10 June 2013 |
| Creators | Chandorkar, Chaitrali Santosh |
| Publisher | PDXScholar |
| Source Sets | Portland State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Dissertations and Theses |
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