In-device high resolution and high throughput optical metrology for process development and monitoring

Abstract

With continuous scaling and increased design and process complexity, there is an increasing need for semiconductor manufacturing process control. This need calls for not only advanced methods and more capable tools, but also additional intra-wafer and across-lot sampling to capture process variations and/or changes in process signatures. In this paper we will demonstrate high speed full wafer metrology use cases from the KLA CIRCL™ platform. CIRCL is a versatile all-surface wafer inspection platform, and its front-side patterned wafer inspection system is typically used for very high throughput inline macro defect inspection. Here we demonstrate that this tool can also be used for certain types of metrology applications. In this paper, we will investigate metrology opportunities with high sampling and full wafer coverage for critical process parameters. We use two test vehicles for demonstration purposes, namely, a 32nm pitch line-space defect vehicle patterned with single exposure EUV (extreme ultraviolet) lithography and an iN7 BEOL (back end of line) integration test vehicle, also patterned with single exposure EUV lithography.