Time-efficient and TSV-aware 3D gated clock tree synthesis based on self-tuning spectral clustering

3D gated clock tree synthesis (CTS) mainly consists of three steps: 1) abstract clock topology generation; 2) layer embedding for minimal TSV allocation and 3) clock tree routing with gate and buffer insertion. In this paper, a self-tuning spectral clustering based nearest-neighbor selection (SSC-NNS) algorithm with parallel structure is proposed to achieve high time efficiency in clock tree topology generation, with reduced runtime. In addition, a postorder traversal based layer embedding (PTLE) strategy is adopted for determining the embedding layer of internal nodes with minimal TSVges. Experimental results show that the proposed method achieves 32% and 82% runtime reduction on ISPD2009 and IBM benchmarks respectively compared with the state-of-the-art 3D work. Besides, the TSV count is also reduced by 46% on ISPD2009 benchmarks.