Patent ID: 6218196
Filing Date: 2001-04-17
Classification: C23F,H01L

Abstract:
A method of etching a metal layer over a semiconductor substrate, the metal layer having a photoresist layer thereon, the method comprising the steps of:introducing the semiconductor substrate into a processing container,introducing, into said processing container, etching processing gases in which a deposition-type gas composed of at least two of C, H, and F is added to main etching processing gas including a Cl.sub.2 gas and a BCl.sub.3 gas;applying a pulse-modulated high-frequency voltage between a pair of electrodes that are provided in said processing container so as to be opposed to each other and to hold said substrate, such that said high frequency voltage is turned on and off to establish a duty ratio;generating a plasma between said pair of electrodes;etching said metal layer by using said plasma; andcontrolling said duty ratio to increase the selective ratio of the etching rate of the metal layer to the etching rate of the photoresist layer.