Control of direct bonding behavior by interlayers

Atmospheric pressure plasma treatments were used to control free surface energy of different areas on silicon wafers before bonding. Surface energy measurements in situ during annealing for this different areas are presented for SF6 etching as well as acetylene, glycidyl methacrylate, tetramethylsilane and C4F8 and coatings. The bonding energy can be permanently reduced by appropriate coatings or surface roughness. The results revel important aspects for the choice of precursors and parameters to obtain high contrast between the treated and untreated areas