Optical and Mechanical Characterization of Thin Membranes for X-ray Lithography

An optical transmission test and a bulge test were designed and tested as part of an endeavor to improve x-ray mask manufacturing. The thicknesses and indices of refraction of silicon nitride membranes were measured with the optical transmission test, and the results were explained using Male's graphical method. The residual stress and bulk modu-lus of silicon nitride membranes and PMMA were measured with the bulge test. The bulge test showed a repeatability error of 3% in residual stress measurements and 6% in bulk modulus measurements. A novel in-situ bulge test for a tungsten sputtering system is proposed for controlling the value of the residual stress of sputtered tungsten. Abstract An optical transmission test and a bulge test were designed and tested as part of an endeavor to improve x-ray mask manufacturing. The thicknesses and indices of refraction of silicon nitride membranes were measured with the optical transmission test, and the results were explained using Mal6's graphical method. The residual stress and bulk modu-lus of silicon nitride membranes and PMMA were measured with the bulge test. The bulge test showed a repeatability error of 3% in residual stress measurements and 6% in bulk modulus measurements. A novel in-situ bulge test for a tungsten sputtering system is proposed for controlling the value of the residual stress of sputtered tungsten. Acknowledgements There are many people who have helped in the production of this thesis. I am indebted to all of my teachers at M.I.T. and at previous schools for helping me to develop my technical skills. I am grateful to my advisor Professor Henry I. Smith for his superb technical guidance and financial support. While busy designing his new lab, Dr. Mark Schattenburg has also enthusiastically guided this research. I would like to thank Scott Hector for his patience in answering my many questions and for his help in preparing a multilayer bulge sample. The technical assistance in the NanoStructures Laboratory also deserves thanks for their outstanding work. Mark Mondol's expert assistance in building the bulge test measurement system was critical to this research. Bob Sisson has been key in fabricating the x-ray masks, and Jimmy Carter has kept the lab running through the many power out-ages. Many thanks to all of the students in the NanoStructures Lab! I would finally like to thank my family and all of my friends for their continuous support, humor, and understanding. Thanks a bunch everyone!!!