Optical Scatter Metrology for Industry

Level: Introductory Length: 4 hours Format: In-Person Lecture Intended Audience: Engineers, scientists, and managers who need to understand and apply the basic concepts of scatter metrology to laboratory research and industrial process control. Some knowledge of calculus is helpful, but the course does not require that the student follow mathematical derivations. The instructor has worked with Thomas Germer (SC492 instructor) to avoid overlap between the two courses. Description: The course emphasizes quantifying, measuring and understanding scatter. A scatterometer will be used during the class to illustrate these issues and students are encouraged to bring samples to the course. Optical scatter, originally used almost exclusively to characterize the stray light generated by optically smooth surfaces, is now being used as a fast, economical way to monitor the surface texture requirements in a variety of industries. For example, as the lighting industry moves to LED’s scatter from a huge number of components is being measured for analysis in stray radiation codes. Texture is an important requirement for the metal producing industry and it changes with roll wear. The appearance of every day appliances (from door hinges to computer cases) varies dramatically with texture. The quality of flat panel displays depends on the scatter characteristics of the screen and components behind it. SEMI and ASTM have responded to the new applications with "scatter standards" to help communication between manufacturers, vendors and customers. The course starts with easier to analyze optical applications and then explores the transition to rougher industry surfaces, where the measurements are easier. Between a good optical mirror and a concrete sidewalk there are thousands of industry surfaces that can be monitored with scatter metrology. There are two key points for these "in-between" surfaces: (1) If the texture changes - the scatter changes and (2) these changes (and product function) cannot be adequately monitored by a single variable - such as RMS Roughness, Haze or Gloss. Students are asked to share as much as they can of their scatter metrology issues. Learning Outcomes: This course will enable you to: - quantify and analyze scatter in terms of BRDF, ARS, TIS, Haze and DSC units - explain the instrumentation for obtaining scatter data and evaluate system calibration - describe and overcome the various difficulties in comparing roughness statistics found from profilometers and scatterometers for both isotropic and non-isotropic samples - convert scatter to roughness statistics if possible and understand when it is not possible - evaluate the use of scatter measurements for specific applications such as: stray system radiation, surface micro-roughness, particulate sizing and background sensor noise - explain the use of polystyrene latex sphere depositions as an optical scattering standard - review scattering standards for the semiconductor and photo-voltaic industries Instructor(s): John Stover is President of The Scatter Works, Inc., a Tucson firm concentrating on scatter based metrology standards, consulting, instruments and measurements as they apply to diverse industries. He has researched light scatter related problems for over 40 years and led teams of engineers who developed state-of-the-art scatterometers, verified theoretical relationship between surface roughness and scatter and characterized surface defects to improve wafer metrology. He has been involved with international standards organizations for over 20 years, is an SPIE Fellow, and has been active as an author, conference chairman, and editor, and has over one hundred publications including the following book. Event: SPIE Photonics West 2016 Course Held: 15 February 2016