Copper CMP at low shear force for low-k compatibility

Copper CMP faces significant technical challenges at the 100 nm technology node and beyond as low-k dielectric materials replace conventional SiO₂ dielectrics. Low shear force becomes the focus of CMP process development. However, the effects of shear force during the CMP process have not been fully explored. In this paper, we studied the polishing shear force under various process conditions. The correlation between polishing shear force and low-k material delamination is experimentally established. A low shear force CMP process is developed that demonstrates low-k compatibility with comparable polishing performance to conventional high shear operation region.