Abstract
Electroless plating is recently used for electronic industry. But, during the deposition of thin films large internal stresses are frequently built into the films. The internal stress in films has been extensively investigated but its origin has not been clarified yet. In order to determine the origin of stress, measurements of stress are required in the initial stage of film growth. In this study, TV holography, which can capture holographic image at TV frame rates, is used to measure sensitively the change in the internal stress in films by recording the change in deflection of the free end of a cantilever beam. The dependence of internal stress upon film thickness for a Cu plating bath on a Be-Cu substrate was discussed. As the results, large stress variation is generated right after the plating, which occurred simultaneously with the adhesion of the plating particle on the substrate by SEM observation. The stress variation is large different in commercial bath and basic bath which removed small additives. This study shows that present method is useful as “in-situ measurement” of internal stress of electroless plating.
