Ultrasonic Thin Film Thickness Measurement

The objective of this proposal is to develop an ultrasonic technique for the measurement of the thickness of thin films in an integrated circuit manufacturing environment. Our approach is to use ultrasound in the regime where the wavelength is comparable to that of light; that is in the frequency range of 1-10 GHz. In this range, it will be possible to measure the thickness of very thin and opaque films. Also, because the mechanical impedances of materials vary significantly more than their dielectric constants, we expect to be able to measure the individual thicknesses of layered thin films. An XY scan will be made to generate film thickness contour map of the wafer. ANTICIPATED BENEFITS: This project will demonstrate the feasbility of a technique which can be developed into a commercial thin/thick film thickness measurement system. Economical, quantitative, simple, inexpensive, and nonrestrictive measurements of the thickness of transparent and opaque, simple and multiple films, will have a great impact on the cost and quality control of thin film deposition in an integrated circuits manufacturing environment.