Simulating Redeposition During Etch Using a Monte Carlo Plasma Etch Model

Introduction

The shrinking critical dimensions of modern technology place a heavy requirement on optimizing the etching of narrow mask opening. In addition the aspect ratio of etches has been increased requiring deeper etches along with the small CDs. The simulation of these process requires more advanced techniques than the directional rate-based etching found in the current versions of Elite. A more complete treatment involving calculation of the plasma distribution is required.

The new Monte Carlo etch module is implemented into ATHENA/Elite. The main application of the module is simulation of plasma or ion assisted etching. The module can take into account the redeposition of the polymer material generated as a mixture of incoming ions with etched (sputtered) molecules of substrate material. In addition, the module has interface to the C interpreter which allows simulation of several other processes like wet etch and deposition, ion milling and sputtering deposition of various materials.