Effective Gap Filling via Magnetic Field Simulation Assisted on Longthrow Sputtering PVD of Side Magnet Designs and Arrangements for 3DIC Application

Abstract

This study used Finite Volume Method to simulate the magnetic profile of PVD (physical vapor deposition) chamber. For this longthrow PVD, the adaptor of the gap filling chamber has 120 mm height and 44 sets of side magnets around the adaptor. The polarity of the side magnets is the same as the top magnets of the chamber. These side magnets can very effectively increase electron mobility and collision frequency with sputtered atoms. The plasma simulation result shows that ionization rate on sputtered atoms can be up to 12% from such a PVD system along with such a magnet arrangement. Therefore, it shows a significant improvement on bottom side-wall coverage of via hole up to 45%. The deposition rate increases by 40%. In addition, the adjustment of RF bias and resputtering power can result in further improvement on 3/4 depth of side-wall coverage by 30% and corner step coverage by 70%. This study uses a simple method to apply 3DIC gap filling capability for an increase of aspect ratio (AR).