Introduction

Abstract

The last fifteen years have seen the broad application of chemical-mechanical planarization, also known as chemical-mechanical polishing (CMP), in sub-micron integrated circuit (IC) fabrication. During a CMP process, a silicon wafer with size (diameter) ranging from 4 inch (100mm) to 12 inch (300mm), patterned or blanket, is rotated about its axis while being pressed facedown by a carrier against a polishing platen covered with a soft polymer pad/belt. Slurries with nano-scale abrasive particles and special chemicals are distributed into the wafer and pad/belt interface. These slurry particles and chemicals work with the pressure P applied on the wafer top surface and the relative movement between the wafer and the pad/belt to remove the wafer materials and planarize the wafer surface. A typical configuration of a rotational type CMP machine, where the relative movement is obtained from the rotations of the wafer carrier (polishing head) and polishing platen around their own centers, is shown schematically in Fig. 1.1 ¹.