Patent ID: 6261926
Filing Date: 2001-07-17
Classification: H01L

Abstract:
A method for fabricating a field oxide on a semiconductor substrate, comprising the steps of:(a) forming successively a first pad layer and a first mask layer;(b) forming an opening in the first mask layer to define a region for forming the field oxide;(c) forming a first field oxide in the opening;(d) removing the first field oxide to form a concave portion;(e) removing the first pad layer exposed by the concave portion to form a cavity;(f) forming a second pad layer having a smaller thickness than the first pad layer on the semiconductor substrate;(g) forming a mask portion in the sidewall of the patterned first mask layer and the cavity, wherein the mask portion in the sidewall of the patterned first mask layer has a thickness less than 300 .ANG.; and(h) carrying out thermal oxidation to form a second field oxide in the concave portion.