Stripping Photo-Resist with RF Dielectric Barrier Atmospheric Pressure Plasma
A novel radio frequency single-dielectric-barrier-discharge atmospheric pressure plasma generator was designed and utilized to strip AZ9912 photo-resist (PR). Argon (Ar) and oxygen (O2) were employed as the working gases under atmospheric pressure in ambient air. The PR stripping rate was measured as functions of time, input power, and the flow rates of the oxygen/argon. Optical Emission Spectroscopy (OES) was used to measure the optical emission spectra of the plasma to study the mechanism of PR stripping process. It is presumable that C-H bands were broken by high energy electron in the plasma and OH was generated in the process with the participation of O atom. Optical Microscope, Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) were used to measure the surface of the silicon substrate after the stripping. It is proved that this kind of novel device could strip the AZ9912 PR effectively as high as 850nm/min, without residues and ion bombardment damage on the wafer substrate.