New registration calibration strategies for MBMW tools by PROVE measurements

Abstract

EUV lithography is currently setting the pace for the semiconductor industry’s expectations on future progress towards the 3nm node and beyond. This technology also defines the upcoming challenges for equipment providers upstream and downstream of the production line among which wafer-level overlay and CD error requirements stand out most prominent. Registration errors on the mask, both local (mid-range) and global (long-range), contribute to overlay errors on the wafer. Here, we will present novel calibration strategies for the IMS Multi-Beam Mask Writer (MBMW) by ZEISS PROVE measurements to meet the mask registration requirements: First, we showcase how we can efficiently leverage the high precision, resolution and fast capture time of the PROVE tool to allow for extensive control and tuning of MBMW properties that affect local registration (LREG) such as systematic residual errors originating from the electron beam optics. Second, we provide insights into the MBMW Registration Improvement Correction (RIC) calibrated with PROVE technology. This feature allows removing remaining systematic local registration errors in the MBMW electron beam array field (82μm x 82μm) resulting in LREG improvement by 30% from 1.2nm to 0.8nm three-sigma. Third, we show how the PROVE technology can be applied efficiently for the calibration of the MBMW’s Thermal Expansion Correction (TEC) that allows compensating systematic global registration errors originating from thermal-mechanical deformations of the mask during the writing process.