Patent ID: 6277752
Filing Date: 2001-08-21
Classification: H01L

Abstract:
A method for forming an isolation region within an isolation trench comprising:providing a semiconductor substrate;forming upon the semiconductor substrate a blanket silicon nitride hard mask layer susceptible to etching within a first plasma etch method, where the first plasma etch method employs a first etchant gas composition which upon plasma activation forms an active fluorine containing etchant species;forming over the silicon nitride hard mask layer a patterned photoresist layer; the patterned photoresist layer leaving exposed a portion of the silicon nitride hard mask layer;etching, while employing the first plasma etch method in conjunction with the patterned photoresist layer as a first etch mask layer, the exposed portion of the blanket silicon nitride hard mask layer to form a patterned silicon nitride hard mask layer which defines an aperture at the bottom of which is exposed a portion of the semiconductor substrate, the first plasma etch method also forming within the bottom of the aperture defined by the patterned silicon nitride hard mask layer a residue upon the exposed portion of the semiconductor substrate;etching, while employing a second etch method, the residue from the bottom of the aperture;etching, while employing a third plasma etch method in conjunction with at least the patterned silicon nitride hard mask layer as a second etch mask layer, the exposed portion of the semiconductor substrate to form an isolation trench within the semiconductor substrate; andforming within the isolation trench a planarized trench isolation region.