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US 6,308,290 B1Granted
Look ahead scan chain diagnostic method
AssigneeInternational Business Machines Corporation
InventorsOrazio P. Forlenza, Mary P. Kusko, Franco Motika
Life of this patent
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Abstract
Look ahead testing process diagnoses broken or stuck-at scan chains to a failing shift register latch for improving the final manufacturing process and suggesting potentials for design change prior to manufacturing in order to improve yield levels. Post test data collection, analysis, and diagnosis can be eliminated.
Claims6
A method for testing and diagnosing broken or stuck-at scan chains in an integrated circuit to locate failed or failing shift registers after application of a predetermined set of test patterns to be used for a set of chips, comprising the steps of:
- (a) generating a set of diagnostic patterns which will be used to identify a failing SRL for a set of chips that are to be diagnosed;
- (b) using said set of diagnostic patterns to diagnose chips that have broken scan chains by using a set of diagnostic patterns in a predetermined order;
- (c) the patterns are examined and a determination is made as to the failing SRL which is identified for each chip being diagnosed, said failing SRL providing a precise location for physical failure analysis;
- and then
- (d) a physical failure analysis is performed to enable process improvements to be made in the technology used during chip manufacturing after understanding the reasons for failures identified during the diagnosis of the chips tested by steps (a) through (c) to make yield improvements to ensure successful production of the chip design with improved yields.
2 more elements
Dependencies are inferred from the claim text.