Hybrid-Row-Height Design Placement Legalization Considering Cell Variants

A new cell-based design paradigm that mixes short rows and tall rows in a layout has emerged to better optimize power, performance and area. We present an effective approach to tackle the placement legalization problem for such hybrid-row-height designs. It takes advantage of the availability of multiple versions of the same cell with different heights and widths to incorporate a cell version change mechanism in the legalization process. Considering cell variants can reduce the required cell displacement from the initial global placement solution and ensure that there is no unlegalizable cell due to the overuse of either kind of resources (short rows or tall rows). Promising experimental results showed the effectiveness of our legalization approach under different row configurations.