Routability-Driven Orientation-Aware Analytical Placement for System in Package

As the challenge of advanced process in ICs increases, system in package (SiP for short) has played a more important role in the semiconductor industry. SiP has several advantages such as heterogeneous integration, lower manufacturing and development cost, and better reliability of preventing mechanical stress. In order to obtain high quality SiP, component placement is the most important stage in an SiP design, and its result not only determines wirelength but also has a great impact on routability. Hence, this paper proposes the first placement algorithm to consider routabiltiy by the analytical formulation for SiP. Furthermore, to obtain the accurate orientations of components, we propose two models by the softmax function to estimate wirelength and density precisely. However, in order to consider the 135 degree routing nets, we also propose a new model to estimate routing overflow to reduce routing congestion by our analytical placement. Experimental results show that our SiP placement algorithm with the proposed models can obtain better results than other works.