Forming trench isolators in semiconductor devices

摘要

A method for forming a trench isolator in a semiconductor substrate comprises: forming a mask layer on the substrate having a opening defining a trench formation region on the substrate; etching the semiconductor substrate through the opening in the mask to form a trench in the substrate; depositing a trench isolation material on the substrate to fill the trench with the isolation material and form a trench isolator in the substrate; planarization-etching the trench isolation material until a top surface of the mask layer is exposed; and, forming a thin protective layer on the surface of the semiconductor substrate. The thin protective layer prevents an edge dipping effect of the trench isolator during subsequent cleaning processes, and enables the planarization-etching to reduce the thickness of the mask layer to the minimum thickness possible, thereby reducing the stresses applied to the semiconductor substrate by the mask layer during subsequent high temperature annealing processes.