Chemical Repair of plasma damaged porous ultra low-k SiOCH film using a vapor phase process

A vapor phase based silylation process was used to restore plasma damaged porous ultra low-kappa SiOCH dielectric films. The process was carried out with eleven different silylation agents. After processing of blanked wafers, the restoration performance was characterized by different analytic techniques like Fourier Infrared and Auger electron spectroscopy as well as contact angle and mercury probe measurements. Quantum mechanics calculations and practical results suggest three repair chemicals having two reactive groups to be most promising. However, a comparable electrical improvement, i.e. kappa-value improvement was achieved with chemicals having one reactive group. A thin dielectric layer formation was found to be one explanation for this effect. This is supported by a high surface free energy recovery after the repair process, without carbon incorporation near the surface. Hence, depending on the requirement to the restoration (kappa-value, carbon restoration, etc.) chemicals having one reactive group can be sufficient as well.