Defect relieving method for floating gate, and semiconductor structure

Abstract

A defect relieving method for a floating gate is disclosed, which includes: providing a front-end structure, including an active region, a gate oxide layer on the active region, a mask layer on the gate oxide layer, a plurality of trenches penetrating through the mask layer, the gate oxide layer, and at least part of the active region, and a filler that is filled in the trenches; performing a first etching process to remove a first thickness of the mask layer between adjacent ones of the trenches; performing a second etching process to remove a remaining thickness of the mask layer between the adjacent trenches, and reducing a width of a portion of the filler that exceeds a top surface of the gate oxide layer, thereby an opening is formed; and filling the opening with a floating gate. The method increases the diameter of the opening, thus avoiding occurrence of voids.