A layout dependent full-chip copper electroplating topography model

Abstract

In this paper, a layout dependent full-chip electroplating (ECP) topography model is developed based on the additive nature of the physics of the EP process. Two layout attributes: layout density, and feature perimeter sum are used to compute the post-ECP topography. Under a unified mechanism, two output variables representing the final topography: the array height and the step height are modeled simultaneously. Using the proposed model long-range effects of the ECP process can be incorporated easily as well. The simulation results of our model were verified with test structure experimental data published in the literature and are presented in this paper. The results show that the errors are less than 5%. This model is not limited to the regular test structures; it can also be used for any practical design. The results of such partial application are shown here as well. Our proposed ECP model can be used to model systematic variations caused by an ECP process or by a chemical mechanical planarization (CMP) process. The potential applications of this model include: layout design evaluation for catastrophic failure prevention; yield aware design (design for manufacturability), and variation- aware timing analysis.