By: Jimmy Gu, SP&I Staff Engineer
Trial and error wafer fabrication is commonly used to study the effect of process changes in the development of FinFET and other advanced semiconductor technologies. Due to the interaction of upstream unit process parameters (such as deposition conformality, etch anisotropy, selectivity) during actual fabrication, variations based upon process changes can be highly complex. Process simulators that mimic fab unit processes can now be used to model these complex interactions. They can also help process engineers identify important process and/or design parameters that drive certain critical targets such as CDs, yield limiting spacing, 3D design rule violations, resistance/capacitance, and other process and design issues. The number of possible parameters that affect device performance and yield can be quite large, so statistical analysis can provide useful insight and help identify critical performance parameters. Coventor’s SEMulator3D virtual fabrication (or process simulation) platform contains an analytics module for conducting virtual design-of-experiments and statistical analysis. I would like to use an example of a 14nm FinFET process flow in SEMulator3D to identify important process parameters that drive fin top CD, which is a key metric for transistor performance.