Wafer Manufacturing

8Chemical Mechanical Polishing

8.1 Introduction

Chemical mechanical polishing (CMP) is commonly employed in two different sets of polishing occasions. The first one is the CMP process to produce the prime (or premium) wafers from ingots. This CMP process is the last step of wafer manufacturing and wafer surface processing from crystal growth to forming to polishing, as illustrated in Figure 2.1. The prime wafers produced after this CMP step, with inspection and packaging, will be ready for microelectronics fabrication. The other CMP process is sometimes called CMP planarization, referring to the processes of making the surface of wafers flat or planarized at various stages of making microchips in microelectronics fabrication processes. This CMP process is performed to remove excess materials or to create a flat foundation for adding the next layer of circuit features.

In this chapter, the CMP process discussed will be the former one for producing prime wafers.

The CMP process has been employed for years to produce the prime (or premium) wafers from ingots, especially for silicon prime wafers. The CMP process is the last step of wafer manufacturing, after a series of wafer surface processes, to produce prime wafers from “bulk crystal growth” to “wafer forming” and wafer “polishing,” as illustrated in Figure 2.1.

A polished silicon wafer with a surface that is particle free with mirror surface finish is required for microelectronics processing to fabricate, using the planar technology, ...