FORMATION OF TUNGSTEN STRUCTURE

摘要

PURPOSE:To form a highly reliable high-density semiconductor device by forming a tungsten structure therein. CONSTITUTION:A thin chromium layer 14 is deposited onto a preselected surface 12 of a semiconductor layer 10 by means of low-pressure chemical vapor growth. A tungsten layer 16 is formed uniformly over thus deposited chromium layer 14. A second thin chromium layer 18 is deposited on the tungsten layer 16. Then, a photoresist layer 20 deposited over a chromium layer 18 is etched by exposing light with a predetermined light pattern to form a photoresist mask 22. The second chromium layer 18 is etched using oxygen/chlorine plasma to form a chromium mask 24. The tungsten layer 16 is etched by using carbon tetrafluoride/chlorine plasma to form a tungsten structure 26. Any part in the chromium mask and the first chromium layer which is exposed by the tungsten etching process is eliminated through the use of an etching plasma consisting of an oxygen ion and a chlorine ion.