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 [4] 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 [8], and obtain feasible solutions with good quality based on minimized effective density. Compared with previous linear programming approach [10] that costs O(n(3)) (pale have n * n panels in chip layout), EMDI is quite fast in O(n log n) which is dominate by fast fourier transformation, same complexity as in [11]. 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 approach in [11], and is more efficient and effective in the smoothness of metal layers.