Patent ID: 11923235
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 14:
15. A method comprising:
forming a first protruding portion and a second protruding portion over a semiconductor substrate, wherein the semiconductor substrate has a first trench exposing a sidewall of the first protruding portion and a second trench exposing a sidewall of the second protruding portion, and the second trench is deeper than the first trench;
filling a dielectric material in both the first and second trenches;
performing a planarization process to the dielectric material until a top surface of the first protruding portion is exposed, wherein the dielectric material comprises a first portion in the first trench and a second portion in the second trench;
after performing the planarization process to the dielectric material, simultaneously etching back the first portion and the second portion of the dielectric material; and
after simultaneously etching back the first portion and the second portion of the dielectric material, further etching back the first portion of the dielectric material such that a top surface of the first portion of the dielectric material is lower than a top surface of the second portion of the dielectric material.