An improved scan design for minimization of test power under routing constraint

Scan cell ordering method is widely applied to reduce test power. Such ordering may result in significant routing overhead. In this paper, we propose a new scan design method to minimize test power under routing constraint. We base on the characteristics of scan cell distribution to cluster them prior to the ordering so as to satisfy routing constraint. Flexible scan cells are identified from each cluster to achieve further reduction of test power under routing constraint. Scan cells are finally ordered based on the evaluation of the transitions caused by connected scan cells during test. The experimental results show that the scan designs by our method can always achieve lower test power than those by other existing optimization method while satisfying the routing constraint.