Abstract: Disclosed herein are methods of controlling the etching of a layer of silicon nitride relative to a layer of silicon dioxide. In one illustrative example, the method includes providing an etch bath that is comprised of an existing etchant adapted to selectively etch silicon nitride relative to silicon dioxide, performing an etching process in the etch bath using the existing etchant to selectively remove a silicon nitride material positioned above a silicon dioxide material on a plurality of semiconducting substrates, determining an amount of the existing etchant to be removed based upon a per substrate silicon loading of the etch bath by virtue of etching the plurality of substrates in the etch bath and determining an amount of new etchant to be added to the etch bath based upon a per substrate silicon loading of the etch bath by virtue of etching the plurality of substrates in the etch bath.

Abstract: Disclosed herein are methods of controlling the etching of a layer of silicon nitride relative to a layer of silicon dioxide. In one illustrative example, the method includes providing an etch bath that is comprised of an existing etchant adapted to selectively etch silicon nitride relative to silicon dioxide, performing an etching process in the etch bath using the existing etchant to selectively remove a silicon nitride material positioned above a silicon dioxide material on a plurality of semiconducting substrates, determining an amount of the existing etchant to be removed based upon a per substrate silicon loading of the etch bath by virtue of etching the plurality of substrates in the etch bath and determining an amount of new etchant to be added to the etch bath based upon a per substrate silicon loading of the etch bath by virtue of etching the plurality of substrates in the etch bath.