The production (molding) guideline to realize ultraclean resin components for semiconductor equipment has been established. In this paper, we focused on the degradation behavior of resin materials for the purpose of reducing low-molecular-weight volatile contaminants concentration in resin components because the molding is carried out at high temperature and low-molecular-weight volatile contaminants are produced by thermal degradation. It was clarified that the oxygen concentration in high temperature molding environment is required to be below 1 ppm. And as the contact surface of the thermal degradation prevention for the resin material, the following surface materials are effective. 1) Passivation surface for a hydrocarbon resin. 2) Ni (nickel) surface for a fluorocarbon resin. As a result, we found the degradation prevention of the resin material can be realized until around 400 °C although the degradation was observed even under 200 °C if using current process condition. Therefore, low-molecular-weight volatile contaminants can be drastically reduced from resin components by using the guideline and ultraclean semiconductor equipment must be realized.