Method and apparatus for plasma etching

Claim 1

A improved system for conducting plasma etching of semiconductor wafers comprising: a process chamber; first and second electrodes mounted in said chamber and arranged so at least one wafer may be disposed between them for etching; means for evacuating said chamber; gas supply means for introducing at least one reactive etching gas to said process chamber; RF power supply means connected to said electrodes so as to ionize said at least one reactive etching gas and provide a plasma that will impinge upon and etch a wafer located between said electrodes said first electrode being characterized by (1) a first gas feeder means comprising a plurality of first discharge openings arranged to discharge said at least one reactive etching gas in a plurality of gas streams extending in a direction that is substantially at a right angle to a the plane of a wafer supported on said second electrode, and (2) a second gas feeder means comprising a plurality of second discharge openings each arranged to discharge said at least one reactive etching gas in a direction that is at an acute angle to the plane of a wafer supported on said second electrode; gas flow control means comprising (a) first means for selectively connecting said first gas feeder means to said gas supply means so that said at least one reactive etching gas will be dispersed via said first discharge openings in a plurality of streams flowing toward said second electrode at a right angle to said second electrode, and (b) second means for selectively connecting said second gas feeder means to said gas supply means so that said at least one etching gas will be dispersed via said second discharge openings in a plurality of streams flowing toward second electrode at an acute angle to said second electrode.

Claim 10

A method of conducting etching of a semiconductor workpiece so as to produce depressions that have chamfered corners, comprising the steps of: (a) providing a semiconductor workpiece that has a mask on one side thereof defining at least one etching aperture; (b) placing said workpiece between first and second electrodes disposed in a process chamber so that said workpiece is proximate to said second electrode and said one side thereof faces said first electrode; (c) coupling an RF power supply across said electrodes so as to create an RF electric field between said electrodes; (d) selectively feeding a reactive etchant gas (1) through first gas feed means arranged to discharge said gas in a plurality of streams directed toward said second electrode perpendicularly to said one side of said workpiece; and (e) selectively feeding a reactive etchant gas through a second gas feed means arranged to discharge said gas through second feed means arranged to discharge said gas in a plurality of streams directed toward said second electrode at an acute angle to said one side of said workpiece; whereby the gas streams discharged from said first and second gas feed means are ionized and accelerated toward said second electrode so as to pass through said at least one etching aperture, with the gas streams from said first gas feed means passing through said at least one etching aperture substantially perpendicularly to said one side to cause formation of a depression in said workpiece having sharp outer corners, and the gas streams from said second gas feed means passing through said at least one etching aperture at an acute angle to said one side to cause chamfering of said outer corners.

Claim 11

A method of conducting etching of a semiconductor workpiece so as to produce depressions that have chamfered corners, comprising the steps of: (a) providing a semiconductor workpiece that has a mask on one side thereof defining at least one etching aperture; (b) placing said workpiece between first and second electrodes disposed in a process chamber so that said workpiece is proximate to said second electrode and said one side thereof faces said first electrode; (c) coupling an RF power supply across said electrodes so as to create an RF electric field between said electrodes; (d) selectively feeding a reactive etchant gas (1) through first gas feed means arranged to discharge said gas in a plurality of streams directed toward said second electrode perpendicularly to said one side of said workpiece; and (e) selectively feeding a reactive etchant gas through a second gas feed means arranged to discharge said gas through second feed means arranged to discharge said gas in a plurality of streams directed toward said second electrode at an acute angle to said one side of said workpiece; whereby the gas streams discharged from said first and second gas feed means are ionized and accelerated toward said second electrode so as to pass through said at least one etching aperture, with the gas streams from said first gas feed means passing through said at least one etching aperture substantially perpendicularly to said one side to cause formation of a depression in said workpiece having sharp outer corners, and the gas streams from said second gas feed means passing through said at least one etching aperture at an acute angle to said one side to cause chamfering of said outer corners.