Preventing a chemical vapor deposition (CVD) chamber from particle
contamination in which a higher low-frequency radio frequency (LFRF)
power and longer process time are provided to vacate the chamber and
perform a pre-heat process. Following that, a pre-oxide layer is formed
on the chamber wall, while a high-frequency radio frequency bias is
provided to the chamber. The high-power LFRF is continuously provided to
the chamber to sustain the temperature of the chamber, and then a main
oxide layer deposition process is performed. The method is able to form
an oxide layer of better quality on a CVD chamber wall, so as to solve
the particle problem in the prior art. Therefore, yield is improved and
the maintenance cost is reduced.