Patent ID: 6093332
Filing Date: 2000-07-25
Classification: H01J

Abstract:
A method for improving photoresist selectivity while etching a via in a dielectric layer underlying a photoresist mask, said dielectric layer being disposed on a wafer, said wafer being positioned on a chuck within in a plasma processing chamber, comprising:flowing an etchant source gas into said plasma processing chamber, said etchant source gas including a fluorocarbon-containing gas and a substantially nonreactive gas;providing a first RF power wave form to a first electrode associated with said plasma processing chamber, said first electrode being different from said chuck;forming a plasma from said etchant source gas, said etchant source gas including a fluorocarbon-containing gas; andproviding a pulsed RF power wave form to said chuck, said pulsed RF power wave form having a first frequency and alternates between a high power cycle and a low power cycle at a pulse frequency, a maximum power level during said low power cycle and said pulse frequency being selected to cause polymer to be deposited on said mask during said low power cycle.