Pattern Density Dependency of the Underlying Layer on O₃-Tetraethylorthosilicate (TEOS) Film Formation

We investigated whether O3-tetraethylorthosilicate (TEOS) film formation by atmospheric-pressure chemical vapor deposition (AP-CVD) creates pattern density effects on the underlying layer. The film thickness ratio of a pattern region to the flat region was 1.5 on a film formed by plasma enhanced chemical vapor deposition using TEOS (PE-TEOS film), and ethanol treatment significantly increased the ratio by 7.0–8.0 times. Moreover, the deposited film became much thicker on the dense pattern region and much thinner on the flat region after ethanol treatment. We propose that the pattern density effect on the deposited film thickness was generated by two types of film formation through each precursor, a polysiloxane with a low deposition rate (DR) on the flat region covered with ethoxy groups (Si-OR), and a silanol with a high DR on the dense pattern region covered with hydroxyl groups (Si-OH).