Surface modification of elastomeric seals to reduce stiction force on various surfaces

Abstract

Elastomers are used in many key applications in semiconductor manufacturing. They have the critical task to maintain vacuum integrity as seals, while elastomer end-effector pads, suction caps and other damping elements made of elastomers play important roles to maintain high efficiency of the semiconductor manufacturing tools. Stiction is a common problem in elastomer parts particularly in sealing applications. We developed Seal-Glide^®, a plasma-based surface treatment method that has been successfully employed to overcome the stiction of the seal on the mating surface. Test methods for measuring static and dynamic stiction forces were developed in-house. Three types of test jigs were manufactured to demonstrate the stiction effect on stainless steel, aluminum, and quartz surfaces. To mimic the operating conditions, a single O-Ring was compressed between two plates to a pre-determined deflection using spacers, and the jig was conditioned in an oven at the target temperature. The jig was later uniaxially loaded in tension by a tensile machine at room temperature and the maximum force to separate the two plates was recorded as the stiction force. Cyclic compression tests were also performed on stainless steel and aluminum surfaces to demonstrate the seals’ performance in dynamic applications. Comparison of the tests performed with various sealing materials under the same testing conditions with and without plasma treatment demonstrated that plasma treatment could lower stiction between the seal and the countersurface by 85%. Such a reduction can represent major benefits in the performance of semiconductor manufacturing tools.