Profile Control by Carriers

The incoming wafer nonuniformity may vary depending on many factors. Especially in case of Cu plating, the nonuniformity of the wafer edge is often poor. Therefore, a CMP process is required to control its polishing characteristics in accordance with the incoming wafer profile. In this section, several profile control methods are introduced as shown in Fig. 3.13. 

Wafvr carrier e(l) c proltte Wafer carrier center profile  

FIGURE 3.14 Schematic illustration of how carrier design can affect the polishing profile. 

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Figure 3.14 shows the polishing profile control by carrier design. The polishing profile of the wafer center area can be modulated by backside pressure and modification at the carrier center. The polishing profile of the... 

Figure 3.16 shows the polishing profile control by carrier and table speeds. Three cases are illustrated (1) table speed is higher than carrier speed, (2) table speed is the same as carrier speed, and (3) table speed is lower than carrier speed. Each velocity vector is shown. 

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