Low friction polish-stop stratum for endpointing chemical-mechanical planarization processing of semiconductor wafers

摘要

The present invention is a semiconductor wafer that enhances polish-stop endpointing in chemical-mechanical planarization processes. The semiconductor wafer has a substrate with a device feature formed on the substrate, a stratum of low friction material positioned over the substrate, and an upper layer deposited on the low friction material stratum. The low friction stratum has a polish-stop surface positioned at a level substantially proximate to a desired endpoint of the chemical-mechanical planarization process. The upper layer, which is made from either a conductive material or an insulative material, has a higher polishing rate than that of the low friction stratum. In operation, the low friction stratum resists chemical-mechanical planarization with either hard or soft polishing pads to stop the planarization process at the desired endpoint.