Patent ID: 6281132
Filing Date: 2001-08-28
Classification: H01L

Abstract:
A dry etch method, comprising:introducing a semiconductor substrate between a pair of electrodes maintained within a reaction chamber;applying a first quantity of low frequency power to the pair of electrodes from an RF power source while a first gas flow is circulated through the reaction chamber, the first gas flow comprising a first inert gas flow, a first oxygen flow, and a first fluorocarbon flow, wherein the ratio of fluorine atoms to carbon atoms within the first fluorocarbon flow is less than 4:1, and wherein said applying a first quantity of low frequency power creates a first plasma;etching a portion of a nitride layer arranged above the semiconductor substrate with the first plasma;terminating applying a first quantity of low frequency power subsequent to etching a portion of a nitride layer;applying a second quantity of low frequency power from the RF power source to the pair of electrodes while a second gas flow is circulated through the reaction chamber, the second gas flow comprising a second inert gas flow and a second fluorocarbon flow, and wherein the ratio of fluorine atoms to carbon atoms within the second fluorocarbon flow is less than the ratio of fluorine atoms to carbon atoms within the first fluorocarbon flow, and wherein said applying a second quantity of low frequency power creates a second plasma; andetching a portion of an oxide layer disposed beneath the nitride layer and above the semiconductor substrate with the second plasma.