Deep trench isolations and methods of forming the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsCheng-Hsien Chou, Hsiao-Hui Tseng, Chih-Yu Lai, Shih Pei Chou, Yen-Ting Chiang, Min-Ying Tsai
Life of this patent
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Abstract
A method includes performing an anisotropic etching on a semiconductor substrate to form a trench. The trench has vertical sidewalls and a rounded bottom connected to the vertical sidewalls. A damage removal step is performed to remove a surface layer of the semiconductor substrate, with the surface layer exposed to the trench. The rounded bottom of the trench is etched to form a slant straight bottom surface. The trench is filled to form a trench isolation region in the trench.
Claims20
A method comprising:
- performing an anisotropic etching on a semiconductor substrate to form a trench, wherein the trench comprises vertical sidewalls and a rounded bottom connected to the vertical sidewalls;
- performing a damage removal step to remove a surface layer of the semiconductor substrate, with the surface layer exposed to the trench, wherein the rounded bottom of the trench is etched to form a slant straight bottom surface;
- and
- filling the trench to form a trench isolation region in the trench.
A method comprising:
- etching a semiconductor substrate to form a trench;
- performing a cleaning on the semiconductor substrate and the trench;
- after the cleaning, performing a damage removal step to remove a surface layer of the semiconductor substrate, with the surface layer being in the trench;
- and
- after the damage removal step, filling the trench to form a trench isolation region in the trench, wherein the filling the trench comprises:
- forming a dielectric layer extending into the trench;
- forming a metal region in the trench and over the dielectric layer;
- and
- etching back the metal region.
A method comprising:
- performing a dry etch on a semiconductor substrate to form a trench extending into the semiconductor substrate, wherein a surface layer of the semiconductor substrate is damaged by the dry etch, and the surface layer is exposed to the trench, and after the dry etch, the trench has rounded bottom surfaces;
- performing a wet etch to remove the surface layer of the semiconductor substrate, wherein the wet etch converts the rounded bottom surface into bottom surfaces with straight edges and straight bottoms;
- and
- filling the trench to form a trench isolation region in the trench.
Dependencies are inferred from the claim text.