For two-pattern at-speed scan testing, the excessive power supply noise at the launch cycle may cause the circuit under test to malfunction, leading to yield loss. This paper proposes a new weight assignment scheme for logic switching activity; it enhances the IR-drop assessment capability of the existing weighted switching activity (WSA) model. By including the power grid network structure information, the proposed weight assignment better reflects the regional IR-drop impact of each switching event. For ATPG, such comprehensive information is crucial in determining whether a switching event burdens the IR-drop effect. Simulation results show that, compared with previous weight assignment schemes, the estimated regional IR-drop profiles better correlate with those generated by commercial tools.

This work proposes a power supply noise reduction technique for at-speed testing in the broadcast-based test compression environment. 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-slices, the efficiency of X-slice filling to lower the launch cycle switching activity is improved. Effectiveness of the proposed technique is validated with ISCAS89 and ITC99 benchmark circuits.

Analysis of power grid IR-drop during scan test application has drawn growing attention because excessive IR-drop may cause a functionally correct device to fail at-speed testing. The analysis is challenging since the power grid IR-drop profile depends on not only the switching cells locations but also the power grid structure. This paper presents a scalable implementation methodology for quantifying the IR-drop effects of a set of switching cells. An example of its application to guide power-safe scan pattern generation is illustrated. The scalability and effectiveness of the proposed quantitative measure is evaluated with a 130 nm industrial design with 800 K cells.

Yield loss caused by excessive power supply noise has become a serious problem in at-speed scan testing. AlthoughX-filling techniques are available to reduce the launch cycle switching activity, their performance may not be satisfactory in the linear-decompressor-based test compression environment. This paper solves this problem by proposing a novel integrated automatic test pattern generation scheme that efficiently and effectively performs compressible low-capture-powerX-filling. Related theoretical principles are established, based on which the problem size is substantially reduced. The proposed scheme is validated by benchmark circuits, as well as an industry design in the embedded deterministic test environment.

This paper presents PHS-Fill, an ATPG technique that reduces(1) power supply noise for scan-based at-speed testing, and(2) test data volume in a Huffman coding based test compression environment. PHS-Fill first identifies the preferred Huffman symbols; these symbols correspond to the test pattern templates that improve test compression and reduces power supply noise at the same time. ATPG then biases its primary input assignments so that the test pattern blocks match the preferred symbols whenever possible. Simulation results on ISCAS89 and ITC99 benchmark circuits show that PHS-Fill is a promising solution.

Yield loss caused by excessive power supply noise has become a serious problem in at-speed scan testing. Although X-filling techniques are available to reduce the launch cycle switching activity, their performance may not be satisfactory in the linear-decompressor-based test compression environment. This work is the first to solve this problem by proposing a novel integrated ATPG scheme that efficiently and effectively performs compressible X-filling. Related theoretical principles are established, based on which the problem size is substantially reduced. The proposed scheme is validated by large benchmark circuits as well as an industry design in the embedded deterministic test (EDT) environment.

Power management is posing serious challenges for scan-based testing. In this paper, we propose a low power test pattern generation technique which minimizes the peak power consumption associated with the scan and capture operations. Given a set of fully specified test patterns, the proposed technique iteratively replaces the high power consumption patterns with low power ones generated by a PODEM-based low power ATPG. The proposed technique has been validated using ISCAS89 benchmark circuits. Compared to a commercial ATPG using high merge ratio and random-fill options, the proposed technique reduces the peak shift and capture power by 27.3% and 19.6%, respectively, and the average power by 49.9%.