Defects After Copper CMP

FIGURE 17.22 Schematic illustration of possible defects after copper CMP in the case of underpolishing. 

In addition to the fact that copper CMP is more complex than the other CMP processes in terms of defect types, there are also many more integration 

FIGURE 17.24 Schematic illustration of some integration options to make a copper damascene structure. 

To simplify the discussion, from this point onward, this section assumes that nonporous low-fc dielectric material and conventional Ta or TaN copper barrier film are employed in the integration scheme. The focus of the discussion shall be on the influence of integration scheme on the type and level of defects. 

---

From defectivity point of view, copper CMP is a challenging process because many types of undesirable features could be left on the surface after CMP. Figures 17.22 and 17.23 illustrate some of these possible defects. 

---