Before being used in an extreme-ultraviolet (EUV) scanner, photoresists must first be qualified to ensure that they will not excessively contaminate the scanner optics or other parts of the vacuum environment of the scanner. At the National Institute of Standards and Technology we have designed and constructed a high-throughput beamline on the Synchrotron Ultraviolet Radiation Facility (SURF III) in order to provide data on the contamination potential of the outgas products of a candidate resist by simultaneously irradiating a witness substrate and a nearby resist-coated wafer with EUV radiation, the so called witness sample test that is currently the resist qualification method required by ASML. We will present results from four sample resists that were subjected to the test. Although the witness-sample test based on irradiating the resist with EUV radiation at 13.5 nm most closely reproduces conditions in a scanner, the limited availability of suitable EUV sources to conduct such tests has led to development of an alternative method which uses e-beam irradiation in place of EUV radiation. We will also present the results of a comparison of these two methods.
Proceedings Title: EUV Lithography 2011
Conference Dates: February 27-March 2, 2011
Conference Location: San Jose, CA
Conference Title: 2011 Advanced Lithography
Pub Type: Conferences
extreme ultraviolet, EUV lithography, photoresist, multilayer mirror, contamination, witness-plate