Cleaning of wafer edge, bevel and back-side with a torus-shaped capacitively coupled plasma

Abstract

A new type of a capacitively coupled plasma source was developed and tested to remove harmful film layers and particles deposited on a wafer's edge, bevel and back-side during film deposition or other semiconductor chip processes. Plasma was generated along 2 mm of an edge and 4 mm of the back-side of the wafer, thereby removing only films and particles on a wafer edge, bevel and back-side without damaging patterns inside the wafer. Etch rates over 10 000 Angstrom min(-1) for SiO2 and SiN films and rates over 6000 Angstrom min(-1) for polysilicon film were obtained.