A Material Removal Rate Model Considering Interfacial Micro-Contact Wear Behavior for Chemical Mechanical Polishing

Abstract

Chemical Mechanical Polishing (CMP) is a highly effective technique for planarizing wafer surfaces. Consequently, considerable research has been conducted into its associated material removal mechanisms. The present study proposes a CMP material removal rate model based upon a micro-contact model which considers the effects of the abrasive particles located between the polishing interfaces, thereby the down force applied on the wafer is carried both by the deformation of the polishing pad asperities and by the penetration of the abrasive particles. It is shown that the current theoretical results are in good agreement with the experimental data published previously. In addition to such operational parameters as the applied down force, the present study also considers consumable parameters rarely investigated by previous models based on the Preston equation, including wafer surface hardness, slurry particle size, and slurry concentration. This study also provides physical insights into the interfacial phenomena not discussed by previous models, which ignored the effects of abrasive particles between the polishing interfaces during force balancing.