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Full electrical testing of devices may require three different insertions within the electrical test process flow: cold, ambient, and hot testing inserts. This paper presents a new approach for reducing the number of inserts during the test process. Known as the Class Test at Sort (CTAS) Methodology, it is basically the complete electrical testing of devices at wafer-level. The CTAS method employs three sort tests to consider temperature testing, while ensuring full DC and AC test parameter coverage. The devices are tested to full datasheet limits with proper correlation to the device packaging. By implementing the CTAS method, the only valid rejects expected at the back-end test are those induced by assembly and burn-in. The study verified that these are primarily continuity and gross functional rejects, which can all be screened out by the first test insert in the back-end electrical test process. This allows the elimination of the second and third test inserts from the back-end test flow.
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