Patent ID: 6017825
Filing Date: 2000-01-25
Classification: H01J,H01L

Abstract:
In an inductively coupled plasma processing system having a plurality of electrodes, said plurality of electrodes consisting essentially of two electrodes: a top electrode and a bottom electrode, said top electrode having a coil configuration, a method for reducing etch rate loading while etching through a portion of a selected layer of a layer stack of a wafer, said method comprising:placing said wafer into said inductively coupled plasma processing system;etching at least partially through said selected layer while:providing a first radio frequency (RF) signal having a first RF frequency to said top electrode, said first RF frequency being about 13.56 MHz;providing a second RF signal having a second RF frequency lower than said first RF frequency to said bottom electrode, said second RF frequency has a range of about 400 kHz to about 4 MHz, said second RF frequency causing said selected layer to be etched at an accelerated rate in narrow regions of said selected layer, thereby lowering said etch rate loading; andproviding RF power having an RF power range of about 50 kW to about 275 kW to said bottom electrode, said RF power range representing a range that does not result in excessive erosion of protective photoresist features of said layer stack by said reactive ion species.