Binary Pseudo Random Array (BPRA) Standards, Protocol, and Software for EUV Lithography Tool Enhancement

We propose a calibration test standard and software to measure the optical response of EUV imaging systems, revolutionizing metrology for EUV lithographic instruments. This solution uniquely offers precision Instrument Transfer Function (ITF) characterization and geometrical distortion assessment using specialized test patterns and data processing software. High precision and accuracy in metrology are critical for both current and future nodes of EUV lithography, essential for powering the world’s advanced computer chips. Currently, EUV optics metrology relies on interferometric measurements during manufacture and on-board sensors for wavefront errors, but this data isn't readily available to end users. Our ITF calibration technology, based on a patented test artifact design, provides a standardized, turn-key system for users to characterize and monitor the performance of EUV lithographic instruments. The test artifact is measured using the actual imaging arrangement, and the captured images are imported into the software for precise optical response characterization. In the field of EUV lithography tools, imaging quality is crucial, with an even greater emphasis on ensuring stability and uniformity across extensive fleets of tools used globally by multiple end users. This approach will facilitate in-situ and portable calibration and alignment standards for high-quality fleet normalization in EUV imaging.