Performance enhancement of ILD by reducing residues during contact W CMP

Metal 1 (M1) inter-layer-dielectric (ILD) bridging and breakdown voltage tail issues were caused by the surface particle during W contact (CT) chemical mechanical polishing (CMP) for some developing copper interconnect process. With the help of transmission electron microscope (TEM) and energy dispersive X-ray (EDX) analysis, the surface particle induced during W CT-CMP was considered to result in the M1-bridge, and then the mechanism of the weak M1 ILD was analyzed. Through post CMP cleaning and CT protrusion optimization, the defect counts were effectively reduced. Further, the M1 performance with copper interconnect process was verified to be improved greatly.