Patent ID: 6207535
Filing Date: 2001-03-27
Classification: H01L,Y10S

Abstract:
A fabrication method for shallow trench isolations, the method comprising steps of:providing a substrate with a first oxide layer and a silicon nitride layer formed in sequence thereon;patterning the first oxide layer and the silicon nitride layer for defining active regions, wherein a portion of the first oxide layer and the silicon nitride layer are removed to form openings;performing an etching process, with the patterned silicon nitride layer serving as a mask, so as to form shallow trenches on the substrate;forming a second oxide layer for covering a profile of the isolation trenches;forming a third oxide layer for covering the patterned silicon nitride layer, sidewalls of the patterned first oxide layer, and the second oxide layer;performing a thermal annealing, so that a portion of the third oxide layer is hardened, while the other portion of the third oxide layer remains softened; andplanarizing the hardened third oxide layer until the silicon nitride layer is exposed to complete the manufacture of the shallow trench isolations.