Scan Architecture With Mutually Exclusive Scan Segment Activation for Shift- and Capture-Power Reduction

Enhancing delay fault coverage through low-power segmented scan

“…Earlier works on segmented scan chains considered stuck-at faults only [17][18][19][20]. In [19,20], it is shown that the same stuck-at fault coverage as that obtained for unsegmented scan designs can be obtained for segmented scan designs. We show, for the first time, that using segmented scan design one can obtain higher delay fault coverage without reducing switching activity reduction during test.…”

“…The test is scanned in segment by segment and a capture cycle is applied after the complete test is scanned in. The capture cycle may be applied to all segments at the same time [17] or to one or more segments at a time [19,20] followed by scanning out the test response again one segment at a time. In [20] it was shown that even if only one segment is allowed to capture test responses one can achieve the same stuck-at fault coverage as that for the unsegmented design.…”

“…Several methods to reduce switching activity during scan based test have been proposed [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Methods proposed in [5][6][7][8] make modifications to scan chains to facilitate reduction of switching activity during scan shift.…”

“…A method that facilitates reduction of switching activity caused by scan shift as well as by capture cycles is the segmented scan first proposed in [17] and investigated in [19,20] for testing stuck-at faults.…”

“…Segmented scan [17][18][19][20] has been shown to be an effective technique in addressing test power issues in industrial designs [18]. To achieve higher shipped product quality, tests for delay faults are becoming essential components of manufacturing test.…”