METHOD FOR ESTABLISHING ETCH STOP POINT IN PLASMA ETCHING PROCESS

摘要

PURPOSE: A method for establishing an etch stop point in a plasma etching process is provided to eliminate the need for an artificial etch stop layer by improving uniformity of a trench depth between wafers in a silicon etching process or damascene dielectric thin film etching process. CONSTITUTION: An etch reactant has a linear proportional relativity with an etch rate. An integral sum of intensity of an optical emission spectrum corresponding to the etch reactant is obtained regarding time. Time taken for the value of the integral sum to reach an established value is regarded as an etch stop point.