On minimizing topography variation in multi-layer oxide CMP manufacturability

Abstract

Due to advanced technology manufacturing variations, dummy metal insertion becomes the key process of VLSI fabrication in reducing wafer-topography variation in Al- based and Cu-based chemical mechanical polishing (CMP) processes. In this paper, we propose a faster and more effective approach to dealing with inter-layer dielectric (ILD) CMP issue, called Effective Model-based Dummy Insertion (EMDI). EMDI selects panels to insert dummy metal by effective CMP low pass filter model, and obtain feasible solutions with good quality based on minimized effective density. Compared with previous linear programming approach that costs 0(n3) (We have n * n panels in chip layout), EMDI is quite fast in O(nlogn) which is dominated by fast Fourier transformation. Multi-layer dummy metal insertion is considered in our framework as well. The experiments on a real design show that our approach has outperformed the previous approach, and is more efficient and effective in the smoothness of metal layers.