System-Level Variation Analysis for Interconnection Networks at Sub-10-nm Technology Nodes Using Multiple Patterning Techniques

This paper analyzes the impact of the interconnect variation at the system level in terms of clock frequency based on a fast and efficient system-level variation-aware design methodology. Various types of interconnect variations are compared, such as the critical dimension for line/core and spacer, etch, chemical mechanical polishing (CMP), and overlay variations. The 3σ values for these independent variation values are extracted from various fabrication processes, including the litho-etch-litho-etch (LELE) double patterning, self-aligned double patterning (SADP), and self-aligned quadruple patterning (SAQP). The results indicate that the impact of the interconnect variation on the clock frequency increases for a processor at a smaller technology node, especially for the CMP variation. For the impact of the combination of five sources of interconnect variations, the processor using the SADP performs the best. The overlay variation and the spacer variation have a larger impact on the LELE double patterning and the SAQP patterning techniques. Up to 8% and 16% of the frequency drops are observed based on 1× and 2× of the default 3σ values, respectively.