Process for fabricating a semiconductor device

A process for fabricating a semiconductor device comprising the steps of:

• forming an etching-stop layer on a wafer providing a plurality of semiconductor substrates;
• patterning the etching-stop layer using a resist as a mask so that the etching-stop layer remains in a region to be an active region and in a peripheral region of the wafer and is removed from a region to be a device isolation region, followed by forming a trench in the region to be the device isolation region;
• depositing on the wafer an insulating film having a thickness greater than or equal to the depth of the trench;
• forming a resist pattern having an opening above the etching-stop layer in the active region adjacent to a device isolation region whose width is greater than or equal to a predetermined value and in the peripheral region of the wafer, followed by etching the insulating film using the resist pattern as a mask;
• and
• polishing the insulating film existing on the resulting wafer for flattening after removing the resist pattern.