OPTIMIZATION OF CONTACT PROCESS WITH MONTE-CARLO STUDY FOR ADVANCED CMOS DEVICES

A new pretreatment method for metallization was developed using on ind uctive coupled plasma (ICP) soft etch with Ar. The ICP soft etch, whic h is used instead of conventional HF pretreatment, is anisotropic etch ing with high-density plasma and low incident energy, and can uniforml y remove native oxide at the bottom of line contact holes. As a result , excellent ohmic characteristics, low junction leakage current and su perior reliability of thin gate oxide can be achieved using the ICP so ft etch with optimized low bias voltage. Furthermore, the mechanism fo r the formation of stable ohmic contacts was theoretically analyzed us ing a Monte Carlo topological simulation. This simulation was especial ly useful in that it helped to yield an understanding of the mechanism controlling removal of the native oxide in anisotropic etching. Using an ICP soft etch with low sputtering yield, it is possible to prevent resputter deposition on the bottom of holes with 0.1 mu m diameter.