Launch Cycle Power Reduction in Broadcast-Based Compression Environment for At-Speed Scan Testing

Abstract

Power supply noise induced test yield loss is challenging at-speed testing. Excessive switching activity during test application results in abnormal IR-drop and may cause a timing-defect-free circuit to fail the delay fault test. Usually, we can use X-fill techniques to solve this problem. n the other hand, as designs become larger and IC fabrication processes advance, the number of test patterns needed has exploded. Therefore, test compression becomes a necessity. Usually, test compression technique is categorized into three: code-based, linear-decompressor-based, and broadcast-based. his thesis is the first attempt to reduce power supply noise in the broadcast-based compression environment for at-speed scan testing. The core technology is the X-slice creation technique; it comprises the scan chain skew insertion hardware and the skew configuration generation algorithm. With the created X-slice, the efficiency of X-filling to lower the launch cycle switching activities is improved. ffectiveness of the proposed technique is validated with ISCAS89 and ITC99 benchmark circuit. We can see that the launch cycle weighted switching activity is reduced by 30% in average with the data volume overhead below 5% for all circuits.