A vapor phase based silylation process was used to restore plasma damaged porous ultra low-κ SiOCH dielectric films. The process was carried out with 11 different silylation agents. After the processing of blanked wafers, the restoration performance was analyzed by different analytic techniques such as Fourier infrared and Auger electron spectroscopy as well as contact angle, ellipsometric porosimetry, and mercury probe measurements. Quantum mechanic calculations and practical results suggest three repair chemicals having two reactive groups to be most promising. However, a comparable electrical improvement, i.e., κ-value improvement, was achieved with chemicals having one reactive group. The removal of water during the high temperature silylation process is suggested to be the main contributor to the κ-value improvement. The recovery of the surface free energy inhibits or retards water from returning after the silylation process. The chemicals with two reactive groups providing the highest degree of silylation are found to be most appropriate for ultra low-κ dielectric (ULK) recovery. But, depending on the requirement for ULK restoration (e.g., κ-value, surface recovery, etc.), chemicals having one reactive group can be sufficient as well.

Ultralow k using a plasma enhanced chemical vapor deposition porogen approach: Matrix structure and porogen loading influences

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The diffusion behavior of different solvents and repair chemicals in a porous SiCOH with pores of similar to 1,5 nm was studied. It was found for molecule with a size <= 1/3 of the pore size the diffusion coefficient (D-e) depends mainly on the size of the molecule, while a size > 1/3 of the pore size does not show a linear dependency of D-e on the molecules size. In this regime D-e is mainly a function of the surface diffusion which depends on the surface energies of the solid and the liquid and adsorption effects. This study show that the porosity and the surface energies influencing the diffusion need to study in order to perform satisfactory cleaning and repair process for ULK dielectric layers

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