METHOD FOR FORMING METAL WIRE LAYER OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for forming a metal wire layer of a semiconductor device is provided to simplify an etching process to from a via hole having a profile and improve productivity of semiconductor devices. CONSTITUTION: A hollow part(37a) has a slant side wall. The second plasma etching process is performed on an insulating portion(34) of a lower surface of the hollow part(37a) which is exposed, so as to form a via hole(34a) exposing a surface of a metal layer pattern. The second plasma etching process is proceeded with by a chemical reaction with the insulating layer(34). An etching gas having a flow ratio of CF4:CHF3="1":0.20-0.3 is used to conduct the second plasma etching process at a pressure 300 to 500mTorr. It is desirable that the etching gas having a flow ratio of CF4:CHF3="1":0.25 is used to carry out the second plasma etching process at a pressure of 400mTorr. The ranges of the flow ratio and the pressure are ranges for controlling a polymer generated during the second plasma etching process. Thus, by controlling the flow ratio of the etching gas within the range, the via hole(34a) can be formed to expose the metal layer pattern(32) and have a side wall more slant than that of the hollow part(37a).