A new performance driven placement method with the Elmore delay model for row based VLSIs

Abstract

In this paper, we present a new performance driven placement method based on path delay constraint approach for large standard cell layout. The proposed method consists of three phases and uses the Elmore delay model to model interconnection delay precisely in each phase. In the first phase, initial placement is performed by an efficient performance driven mincut partitioning method. Next, an iterative improvement method by nonlinear programming improves the layout. The improvement is formulated as the problem of minimizing the total wire length subject to critical path delays. Finally, row assignment considering timing constraint is performed. From the experimental results, the proposed method is much better than RITUAL in point of the maximal violation ratio, the total wire length, and the cut size, and is more effective in the interconnection delay model and its extendability.