Wen-Chieh Lee

Abstract

An excimer laser incident on a metallic thin film is used to measure the adhesion between the film and the substrate. The initial optical absorption leads to electron excitation. After collisions and degradation of the excited electrons, the absorbed energy is transferred into various kinds of energy among which the major one is thermal. The superheated surface undergoes vapor explosion which serves as one source of shock wave to break the thin film. The evaporated particles may recoil back to the surface constructing another shock wave to break the film. In addition, a tensile stress may be formed by the large difference of thermal expansion between metallic thin film and polymeric substrate. All these effects cooperate to cause the cracking of the metallic thin film. This thesis provides the theoretical models to explain how the various mechanisms work on adhesion evaluation. Based on these understandings, the experimental data of laser ablation test is more suggestive and meaningful than the tape test which is sometimes ambiguous due to undiscerned effects. The experimental results show that laser ablation is sensitive to small differences in adhesion. In addition, the laser ablation test has a broader range of measurement as compared to that of tape test. One thing to be noticed is that laser ablation test is strongly affected by the thickness of the film.

Library of Congress Subject Headings

Thin films--Testing; Excimer lasers

Publication Date

9-22-1990

Document Type

Thesis

Department, Program, or Center

Center for Materials Science and Engineering

Advisor

Lindberg, Vern

Advisor/Committee Member

Entenberg, Alan

Advisor/Committee Member

Wojciechowski, Paul

Comments

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works. Physical copy available through RIT's The Wallace Library at: TK7871.15.F5 L43 1991

Campus

RIT – Main Campus

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