Major Influences of Shaping and Profiling of Cu ECP and CMP on Feature Level

Abstract:
The variety of Cu CMP process parameters are typically optimized empirically. A key goal is the suppression of variations. One of the most important input parameters is considered to be the performance of the incoming wafer like as-deposited Cu profile, variation of thickness and dimension etc. Specifically design aspects like pattern density and feature size are sensitive to copper deposition and CMP process specifics. Different electrochemical plating (ECP) processes were compared in terms of their surface profiles. Certain features sizes were found to be critical and specific pattern densities provide different Cu over plate on the top of these patterns depending on the type of ECP process. In case pattern dependent post plating thickness require additional over polish and hence has a strong influence on post CMP characterization parameters like planarity etc. Based on the mentioned parameters and dependencies the fluctuation of the pre-CMP incoming material can be minimized in order to stabilize post CMP planarity performance. Data are based on 200 mm production data analysis at a given process but are considered to be extendible.