Insulating trench forming method
AssigneeSTMicroelectronics (Crolles 2) SAS
InventorsNayera Ahmed, François Roy
Life of this patent
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Abstract
A method of manufacturing an insulating trench including the successive steps of: a) forming, on a semiconductor substrate, a first masking structure including a layer of a first selectively-etchable material and etching a trench into the substrate; b) forming an insulating coating on the trench walls and filling the trench with doped polysilicon; c) forming a silicon oxide plug penetrating into the trench substantially all the way to the upper surface of the substrate and protruding above the upper surface of the substrate; and d) removing the layer of the first material.
Claims26
A method of manufacturing an insulating trench, the method comprising:
- forming a trench having trench walls in a surface of a substrate;
- covering the trench walls with an insulating material;
- filling the trench with doped polysilicon;
- and
- forming a silicon oxide plug over the polysilicon, an upper surface of the silicon oxide plug located above the surface of the substrate and a lower surface of the silicon oxide plug being substantially at or below the surface of the substrate;
- and
- forming an insulator layer on the surface of the substrate and the upper surface of the silicon oxide plug.
An insulating structure formed in a semiconductor substrate, the insulating structure comprising:
- a trench having trench walls formed in a first surface of the substrate;
- an insulating material covering the trench walls;
- doped polysilicon in the trench;
- and
- a silicon oxide plug formed over the polysilicon, an upper surface of the silicon oxide plug located above the first surface of the substrate, and a lower surface of the silicon oxide plug being below the first surface of the substrate and in the trench.
A semiconductor structure comprising:
- a semiconductor substrate having a surface;
- a plurality of trenches having sidewalls formed in the substrate at the first surface, the plurality of trenches being spaced apart from each other;
- a first layer of insulating material conforming to the sidewalls of a first trench of the plurality of trenches;
- doped polysilicon in the first trench over at least a portion of the first layer of insulating material;
- a silicon oxide plug formed over the polysilicon in the first trench, an upper surface of the silicon oxide plug located above the substrate and a lower surface of the silicon oxide plug being below the first surface of the substrate;
- a second layer of insulating material formed over the silicon oxide plug and
- a conductive gate located between two adjacent trenches.
A method of manufacturing an insulating trench, the method comprising:
- forming a trench having trench walls in a surface of a substrate;
- covering the trench walls with an insulating material;
- filling the trench with doped polysilicon;
- forming a silicon oxide plug over the polysilicon, a first surface of the silicon oxide plug located above the surface of the substrate and a second surface of the silicon oxide plug being substantially at or below the surface of the substrate, the forming of the silicon oxide plug including:
- performing a thermal oxidation to form said oxide plug;
- or
- depositing silicon oxide over the polysilicon and planarizing the silicon oxide.
A method of manufacturing an insulating trench, the method comprising:
- forming, on a surface of the substrate, a masking structure having a layer of a selectively etchable first material, the first material being silicon nitride;
- forming a trench having trench walls in the first masking structure and the substrate;
- covering the trench walls with an insulating material;
- filling the trench with doped polysilicon;
- and
- forming a silicon oxide plug over the polysilicon, a first surface of the silicon oxide plug located above the surface of the substrate and a second surface of the silicon oxide plug being substantially at or below the surface of the substrate.
A method of manufacturing an insulating trench, the method comprising:
- forming a first trench having trench walls in a surface of a substrate;
- covering the trench walls with a first insulating material;
- filling the trench with doped polysilicon;
- and
- forming a silicon oxide plug over the polysilicon, an upper surface of the silicon oxide plug located above the surface of the substrate and a lower surface of the silicon oxide plug being substantially at or below the surface of the substrate;
- forming a second trench in the surface of the substrate, the second trench having a smaller depth than the first trench;
- depositing a second insulating material to fill the second trench;
- and
- planarizing the second insulating material to have an upper surface that is coplanar with the upper surface of the silicon oxide plug.
Dependencies are inferred from the claim text.