PATTERN AND PROCESS DEPENDENCIES IN COPPER DAMASCENE CHEMICAL MECHANICAL POLISHING PROCESSES

In this paper we present experimental data that shows the dependence of copper dishing and oxide erosion on pitch and pattern density, as well as on polishing process parameters including table speed, down force, and process sequence. Specifically, the data shows that the degree of dishing and erosion strongly depends on both the processing parameters and layout factors (density and pitch). We find that a multiple step polish is able to achieve better polishing results compared to a single step polish process. Furthermore, we observe an interesting break point for both erosion and dishing at an oxide line space of approximately 100 μ m. It is also observed that the interaction distance, the length over which a pattern parameter is computed, is significantly shorter than that of conventional oxide polish.