Method and apparatus to minimize seam effect during teos oxide film deposition

A method of minimizing a seam effect of a deposited TEOS oxide film during a trench filling process performed on a semiconductor substrate in a semiconductor substrate plasma processing apparatus, the method comprising:

• supporting a semiconductor substrate on a pedestal in a vacuum chamber of the semiconductor substrate plasma processing apparatus wherein the semiconductor substrate includes at least one trench in an upper surface thereof;
• flowing process gas including TEOS, an oxidant, and argon through a face plate of a showerhead assembly of the semiconductor substrate plasma processing apparatus into a processing region of the vacuum chamber above the upper surface of the semiconductor substrate;
• supplying RF energy into the processing region of the vacuum chamber with at least one RF generator to energize the process gas into a plasma;
• and
• depositing TEOS oxide film on the upper surface of the semiconductor substrate so as to fill the at least one trench thereof wherein the argon is supplied in an amount sufficient to increase the electron density of the plasma such that the deposition rate of the TEOS oxide film towards the center of the semiconductor substrate is increased and the seam effect of the deposited TEOS oxide film in the at least one trench is reduced.