Damage Measurement for Molybdenum Thin Film Using Reflection-Type Digital Holography

Abstract

In the fabrication of electronic circuits used in electronic products, molybdenum thin films are deposited on semiconductors to prevent oxidation. During the deposition, the presence of a particle or dust at the interface between the thin film and substrate causes the decrease of adhesion, performance, and life cycle. In this study, a damage measurement targeting two kinds of glass substrate, with and without particles, was performed in order to measure the change in the molybdenum thin film deposition area in the presence of a particle. Clean and dirty molybdenum thin film specimens were fabricated and directly deposited on a substrate using the sputtering method, and a reflection-type digital holographic interferometer was configured for measuring the damage. Reflection-type digital holography has several advantages; e.g., the configuration of the interferometer is simple, the measurement range can be varied depending on the magnification of a microscopic lens, and the measuring time is short. The results confirm that reflection-type digital holography is useful for the measurement of the damage and defects of thin films.

Measurement of specular surfaces using electrically tunable lens in digital holography

“…In practice, to image microstructures, microscope objectives are employed in digital holography. This technique, called digital holographic microscopy, has also been largely utilized to find the surface profiles of specular [22,23] and diffusely reflecting objects [24][25][26][27]. However, the numerical refocusing property of digital holography works only in the depth of focus of the microscope objective.…”