Pad Microstructures and Macrostructures

The physical and mechanical properties of a polishing pad are determined not only by the chemical composition of the pad materials but also by its microstructures. As described in Table 5.1, each type of pad has its unique microstructure that ranges from large open pores to nonporous solids. Some representative microstructures of pad surfaces are shown in Fig. 5.1. 

Cross-sectional SEM images of type III and type IV pads are shown in Fig. 5.2. Cross-sectional SEM images of all the four types of pads have also been reported in other publications [1]. 

FIGURE 5.1 SEM images of surface of four different types of polyurethane pad [2] (a) type I pad (SubaSOO ), (b) type II pad (URIOO ), (c) type III pad (ICIOOO ), (d) type IV pad (OXP4000 , grooved). 

FIGURE 5.3 Schematic cross section of a multilayer polishing pad [2], 

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