To examine the polishing mechanism in chemical mechanical polishing of a th
ermally grown SiO2 film by CeO2 particles, the surface structure of the fil
m and the polishing waste were investigated by various analytical means. Fo
urier-transformed-infrared-attenuated-totra indicated that the film surface
structure was strained as a result of a reaction with CeO2. A small amount
of Si was found by inductively coupled plasma-atomic emission spectroscopy
(ICP-AES) in the waste supernatant and it was detected as particles by opt
ical interference measurement. The scanning electronic microscopy (SEM) ima
ge of the particles showed a not-well-defined shape like cotton scraps, but
their IR transmission spectrum resembled that of the SiO2 film. From these
results we concluded that the SiO2 film surface is first reacted with CeO2
particles and a multiple number of chemical bondings of Si-O-Ce are formed
on the surface. Then mechanical tearing of Si-O-Si bonds leads to the SiO2
removal as a lump instead of Si(OH)(4) monomer, and the lump is released f
rom the CeO2 particles downstream. (C) 2001 Elsevier Science B.V. All right
s reserved.