Methods of forming trench isolation regions using preferred stress relieving layers and techniques to inhibit the occurrence of voids

摘要

Methods of forming trench isolation regions include the steps of forming a trench in a semiconductor substrate and lining the trench with a first electrically insulating layer. A stress-relief nitride layer is then formed on the first electrically insulating layer, opposite sidewalls of the trench. The trench is then filled with a second electrically insulating layer. The second electrically insulating layer is then planarized. This is followed by the steps of etching the stress-relief nitride layer and then forming a third electrically insulating layer on the planarized second electrically insulating layer and on the stress-relief nitride layer. The step of forming the trench is preferably preceded by the step of forming a patterned pad nitride layer on the semiconductor substrate. The pad nitride layer may be used as a mask when etching the substrate to define the trench. The step of planarizing the second electrically insulating layer may also comprise the step of planarizing the second electrically insulating layer using the patterned pad nitride layer as an etch stop.