Surface Analysis of Dielectric Thin Films by Contact Angle Measurements

The surface characteristics of the surface energy which provides information about hydrophilic/hydrophobic material properties, can be analyzed by contact angle measurements on the surface of thin films. In this paper, we investigate the surface characteristics of three dielectric films of silicon oxide, aluminum oxide, and fluorocarbon copolymer by contact angle measurements. By analyzing the surface characteristics of each film through the key contact angle parameters of the wetting angle and surface energy, we demonstrate the effect of a UV irradiation treatment on the surface characteristics of such a film. We also investigate the contact angle of dielectric films as a function of the UV irradiation time and the aging time. The rate of hydrophilic conversion and the rate for the reverse process resulting from the aging effect were extracted by the slope of the linear fitting line derived from the reciprocal of the contact angle corresponding to the UV irradiation time and the aging time. It is remarkable that the surface characteristics and the effect of a surface treatment on the fabricated dielectric films can be analyzed in such a diverse manner of a practical contact angle measurement.