Optical substrate thickness measurement system using hybrid fiber-freespace optics and selective wavelength interferometry
Abbreviated Journal Title
INTRAOCULAR DISTANCES; WHITE-LIGHT; CONSTANTS; INDEX; PHASE; LASER; Optics
Proposed and demonstrated is a simple few components non-contact thickness measurement system for optical quality semi-transparent samples such as Silicon (Si) and 6H Silicon Carbide (SiC) optical chips used for designing sensors. The instrument exploits a hybrid fiber-freespace optical design that enables self-calibrating measurements via the use of confocal imaging via single mode fiber-optics and a self-imaging type optical fiber collimating lens. Data acquisition for fault-tolerant measurements is accomplished via a sufficiently broadband optical source and a tunable laser and relevant wavelength discriminating optics. Accurate sample thickness processing is achieved using the known material dispersion-data for the sample and the few (e.g., 5) accurately measured optical power null wavelengths produced via the sample etalon effect. Thicknesses of 281.1 mu m and 296 mu m are measured for given SiC and Si optical chips, respectively. (c) 2006 Elsevier B.V. All rights reserved.
"Optical substrate thickness measurement system using hybrid fiber-freespace optics and selective wavelength interferometry" (2007). Faculty Bibliography 2000s. 7580.