Method of forming a bottle-shaped trench
OwnerShian-Jyh Lin, Chen-Chou Huang +3inventors
InventorsShian-Jyh Lin, Chen-Chou Huang, Ming-Cheng Chang, Hsien-Hao Liao, Meng-Hung Chen
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Abstract
A method of forming a bottle-shaped trench. A trench is formed in a substrate, wherein the trench has a surface with an upper portion and a lower portion beneath the upper portion. A dielectric layer is formed on the trench surface at the lower portion. Using the dielectric layer as a mask, a nitridation procedure is performed to form a nitride film on the trench surface at the upper portion. The dielectric layer is removed. Using the nitride film as a mask, an isotropic etching procedure is performed to form a space in the trench at the lower portion. Thus, a bottle-shaped trench is formed.
Claims16
A method of forming a bottle-shaped trench, comprising the steps of:
- providing a substrate;
- forming a trench in the substrate, wherein the trench has a trench surface with an upper portion and a lower portion beneath the upper portion;
- forming a dielectric layer on the trench surface at the lower portion;
- using the dielectric layer as a mask, performing a nitridation procedure to form a nitride film on the trench surface at the upper portion;
- removing the dielectric layer;
- and
- using the nitride film as a mask, performing an isotropic etching procedure to form a space in the trench at the lower portion.
A method of forming a bottle-shaped trench, comprising the steps of:
- providing a silicon substrate, wherein the silicon substrate comprises single crystal silicon;
- forming a trench in the silicon substrate, wherein the trench has a trench surface with an upper portion and a lower portion beneath the upper portion;
- forming a conformal dielectric layer on the trench surface;
- filling a photoresist layer in the trench;
- partially etching back the photoresist layer to form a remaining photoresist layer on the dielectric layer at the lower portion;
- using the remaining photoresist layer as a mask, removing the dielectric layer at the upper portion to leave a remaining dielectric layer on the trench surface at the lower portion;
- removing the remaining photoresist layer;
- using the remaining dielectric layer as a mask, performing a rapid thermal nitridation (RTN) procedure to form a Si3N4 film on the trench surface at the upper portion;
- removing the remaining dielectric layer;
- and
- using the Si3N4 film as a mask, performing a wet etching procedure to form a space in the trench at the lower portion.
Dependencies are inferred from the claim text.