Change of Refractive Index and Thickness of Porous Spin-On-Glass

Films during Exposure to Ar, O2, and H2 Plasma

E.Kondoh1, H.Arao2 and A.Nakashima2

1Yamanashi University, Faculty of Engineering, Department of Mechanical System Engineering, Takeda 4-3-11, Kofu 400-8511, Japan.

2Institute for Fine Chemicals Research, CCIC, Kitaminato 13-2, Wakamatsu, Kitakyushu, Fukuoka 808-0027, Japan.

Abstract

In this paper the change in refractive index and thickness of porous spin-on-glass (SOG) films during plasma exposure is reported. Three different gases are used in terms of their chemical nature, namely inert (Ar), oxidative (O2), and reductive (H2) gases. The plasma exposure resulted in a decrease in .film thickness due partly to shrinkage driven by chemical reactions and also to sputtering. The amount of shrinkage and that of sputtering are quantitatively discussed based on the polarization theory. It is found that the relative contribution of each component depends on the presence of substrate bias and the kind of plasma source gas.