Patent ID: 11972972
Assignee: WINBOND ELECTRONICS CORP.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 7:
8. A manufacturing method of an isolation structure, comprising:
forming a first trench and a second trench at a surface of a substrate, wherein a width of the second trench is greater than a width of the first trench;
forming a mask pattern on the substrate, wherein the mask pattern has a first opening communicated with the first trench, and has a second opening communicated with the second trench;
filling a first isolation material layer into the communicated first trench and first opening as well as the communicated second trench and second opening, wherein a surface of the first isolation material layer defines a first recess;
filling a second isolation material layer into the first recess;
removing a portion of the second isolation material layer and a portion of the first isolation material layer, to form a third recess in the first opening, and form a fourth recess in the second opening;
performing a first ion implantation process, during which first ions obliquely strike the third and fourth recesses from a first side of the third and fourth recesses, to form a first damage region at least in the first isolation material layer;
performing a second ion implantation process, during which second ions obliquely strike the third and fourth recesses from a second side of the third and fourth recesses, to form a second damage region at least in the first isolation material layer, wherein the first and second sides are opposite sides of the third and fourth recesses;
performing a decoupled plasma treatment, to transform portions of the first and second damage regions into protection layers, wherein the protection layers have an etching selectivity with respect to the first and second damage regions; and
removing the first and second damage regions, wherein the isolation structure at least comprises remained portions of the first isolation material layer.