FreePDK15

Abstract

This paper discusses design rules and layout guidelines for an open source predictive process design kit (PDK) for multi-gate 15nm FinFET devices. Additional design rules are introduced considering process variability, and challenges involved in fabrication beyond 20nm. Particularly, double patterning lithography is assumed and a unique set of design rules are developed for critical dimensions. In order to improve the FinFET layout density, Middle-of-line local interconnect layers are implemented for the FinFET layout. The rules are further validated by running Calibre design-rule checks on Virtuoso layout of an Inverter and NAND4 cells. As part of the validation process, the area of a FreePDK15 inverter was compared to the area of an inverter in 45nm bulk MOS process and the ratio was found to be 1:6. This kit primarily aims to support introduction of sub-20nm FinFET devices into research and universities.