A Physical-Location-Aware X-Filling Method for IR-Drop Reduction in At-Speed Scan Test

The IR-drop problem during test mode exacerbates delay defects and results in false failures. In this paper, we take the X-filling approach to reduce the IR-drop effect during an at-speed test. The main difference between our approach and the previous X-filling approaches lies in two aspects. The first one is that we take the spatial information into consideration in our approach. The second one is how X-filling is performed. We propose a backward-propagation technique instead of a forward-propagation approach taken in previous work. The experimental results show that our approach can reduce 21.1% of the maximum IR-drop in the best case and 9.1% on the average as compared to previous work.