Kinetics Study of Disulfide Self Assembly Monolayer (SAM) Deposition for Cu-EMC Adhesion Promotion

This paper presents a study of disulfide self assembly monolayer (SAM) onto sputtered Cu substrate. Extrinsic parameter includes substrate roughness, solution concentration, deposition time and agitation has been investigated. Ellipsometer was used to measure the SAM thickness to investigate impact of process parameter on homogenous film quality. 50 A sputtered Cu on Si wafer having roughness of around 10 A is recommended to be used as substrate in the process. It has been discovered that agitation which prevents local concentration of disulfide solution, is crucial for success of film deposition. Without agitation, larger thickness variation has been attained (36plusmn22 A comparing with 30plusmn16 A). Furthermore, relatively uniform film (37plusmn10 A for DS-A, 30plusmn8 A for DS-C) can be realized from low concentration (0.5 muM) ethanol in 1 hr. Atomic force microscope (AFM) has been used to probe topography images of deposited film. No significant aggregates but few pinholes have been found on disulfide treated surface. An experiment procedure in obtaining uniform thin film from disulfide solution on Cu substrate has been investigated.