John Michael Legare

Thermal stability and sealing performance of perfluoroelastomer seals as a function of crosslinking chemistry

Perfluoroelastomer (e.g., Kalrez®, Chemraz®, etc.), fluoroelastomer (e.g., Viton®, etc.), and silicone parts are widely used in sealing applications for semiconductor wafer processing equipment. More specifically, they are often used as o-ring seals in dry chemical process equipment (e.g., plasma etchers, ashers, diffusion furnaces, chemical vapor deposition, low pressure chemical vapor deposition, rapid thermal processing, and lamp anneal, etc.). Many of these seals are required to function at process temperatures ranging from 200–300 °C and in some cases higher. The ability of an elastomer to resist thermal degradation has a significant impact on its ability to function effectively as a seal over time. This article evaluates and compares the relative long term sealing performance of perfluoroelastomers having different crosslinking chemistries and other typically specified high performance elastomers. Long-term compression set and seal force retention data are presented, including a discussion of the di...

Outgassing characterization of elastomeric seals used in semiconductor wafer processing

High or ultra-high vacuum (UHV) processes for integrated circuit manufacturing require close control of vacuum levels and uniform gas composition in the chamber in order to insure optimum process efficiency, product uniformity and product consistency. Outgassing from elastomeric seals can affect both vacuum level and consistency. A test methodology has been developed using a residual gas analyzer to measure the outgassing properties of elastomers. This paper compares the outgassing characteristics of three different types of elastomeric seals (perfluo-roelastomers, fluoroelastomers and silicones) typically used in semiconductor wafer processing using this test method. Data on outgassing rate as a function of time and temperature are presented. While perfluoroelastomers as a material class exhibit the lowest outgassing rate at elevated temperatures, there are some performance variations depending on formulation and compounding.