Erosion properties of high purity alumina (Al2O3) and yttria(Y2O3) coatings prepared by plasma spraying have beeninvestigated against process plasma in semiconductor andliquid-crystal-display (LCD) production equipments for dryetching. Studies on plasma power dependency have revealedthat yttria coatings have showed higher anti-plasma erosionresistance than alumina coating as well as sintered aluminabulk at every condition. Although yttria coatings are inferiorto sintered yttria bulk, the difference of the resistance becomessmaller with increasing plasma power. This result positivelypromotes the application of the yttria spray coating because ofincreasing plasma power in actual process.Erosion properties of the coatings against Ar/CF4/O2 plasma,whose composition is increasingly being used in commercialprocess, are also investigated where physical etching effectbecomes stronger than the typical CF4/O2 case. It has beenfound that order of durability (yttria bulk > yttria coatings >alumina bulk > alumina coating) is independent of the gasspecies used in this study. The mechanism of the plasmaerosion is discussed through micro-structural analysis of theeroded surfaces.
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