J. Kitamura, Fujimi incorporated, Kakamigahara, Japan; H. Ibe, H. Mizuno, I. Aoki, Fujimi Incorporated, Kakamigahara, Gifu, Japan
The size of semiconductor production equipments for dry etching, sputtering and ashing has been increasing due to increasing Si wafer size, where plasma is effectively used for micro fabrication on the Si wafer. Recently, increase of the plasma power due to increasing equipment size has caused unreliability of the alumite film (anodizing treatment), which is conventionally used as a shield to protect the chamber parts from the process plasma. This trend strongly promotes substitution from the alumite film or bulk ceramics to plasma sprayed ceramic coatings, such as alumina and yttria. Our previous study using reactive ion etching (RIE) systems has revealed that yttria is superior to alumina about 5 times or more. Particle size of the yttria affects erosion resistance against CF4/O2 plasma, where both chemical and physical etchings erode the coatings. In this study, erosion properties of yttria and alumina coatings against Ar/CF4/O2 plasma, whose composition is widely used in commercial process, are investigated using the RIE systems, where physical etching effect may become stronger than the CF4/O2 case. Mechanism of the plasma erosion is discussed by changing the gas composition, micro-structural and chemical analysis of the eroded coating surfaces.
Summary: Recently, plasma spray coatings of yttria and alumina with higher purity of more than 99.9% are applied to semiconductor production equipments and its market is sharply growing due to increasing Si wafer size and micro fabrication of Si devices.
Our previous study using reactive ion etching (RIE) systems has revealed that yttria is superior to alumina about 5 times or more. Particle size of the yttria affects erosion resistance against CF4/O2 plasma, where both chemical and physical etchings erode the coatings.
In this study, erosion properties of yttria and alumina coatings against Ar/CF4/O2 plasma, whose composition is widely used in commercial process, are investigated using the RIE systems, where physical etching effect may become stronger than the CF4/O2 case. Mechanism of the plasma erosion is discussed by changing the gas composition, micro-structural and chemical analysis of the eroded coating surfaces.
