PROJECT TITLE :

Effects of Slurry in Cu Chemical Mechanical Polishing (CMP) of TSVs for 3-D IC Integration

ABSTRACT:

In this paper, the optimization of Cu chemical-mechanical sprucing (CMP) performance (dishing) for the removal of thick Cu-plating overburden thanks to Cu plating for deep through silicon via (TSV) during a 300-mm wafer is investigated. Moreover, backside isolation oxide CMP for TSV Cu exposure is examined. To obtain a minimum Cu dishing on the TSV region, a proper selection of Cu slurries is proposed for the present 2-step Cu-sharpening process. 1st, a bulk of Cu is removed with the slurry of high Cu removal rate and second, the Cu surface is planarized with the slurry of high Cu passivation capability. The Cu dishing will be improved up to ninety sevenp.c for the 10-$murm m$-diameter TSVs on a 300-mm wafer. The dishing/erosion of the metal/oxide will be reduced with respect to a correspondingly optimized Cu-plating overburden for TSVs and redistribution layers. Cu metal dishing will be drastically reduced once the Cu overburdens are increased to a important thickness. For backside isolation oxide CMP for TSV Cu exposure, the results show that the Cu studs of TSVs with a bigger TSV diameter still keep during a plateau-like shape after CMP.