Patent ID: 7788058
Filing Date: 2010-08-31
Classification: G01R

Abstract:
1. A method for diagnosing a scan chain, the method comprising: detecting leakage light emission from a plurality of components in a scan chain design; responsive to detecting leakage light emission from the plurality of components, identifying a first logical value for a first latch of the plurality of components based on the leakage light emission for the first latch; responsive to identifying that the first logical value for the first latch is an unexpected logical value for the first latch, identifying a second logical value for a second latch of the plurality of components based on the leakage light emission for the second latch, wherein the second latch precedes the first latch in the scan chain design; responsive to identifying that the first logical value for the first latch is an expected logical value for the first latch, identifying whether the first latch is a first latch having unexpected light emissions; responsive to identifying that the first latch is not the first latch having unexpected light emissions, identifying a third logical value for a third latch of the plurality of components based on the leakage light emission for the third latch, wherein the first latch precedes the third latch in the scan chain design; and identifying at least one failed component of the plurality of components in the scan chain design based on the leakage light emission.