Method for filling asymmetric deep trench and preparation method of semiconductor device

By controlling the top sealing position of pores in asymmetric trenches with large aspect ratios through polycrystalline silicon deposition and thermal oxidation processes, the problem of difficult filling in existing technologies is solved, and efficient trench filling is achieved, which is suitable for the production of silicon photonics and MEMS products.

CN116153851BActive Publication Date: 2025-10-24SHANGHAI IND U TECH RES INST
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Patent Information

Application Number
CN202111392291.X
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2021-11-19
Publication Date
2025-10-24
Estimated Expiration
2041-11-19

AI Technical Summary

Technical Problem

Existing technologies cannot effectively control the top position of asymmetric, high aspect ratio silicon trenches, leading to filling difficulties, especially in thick silicon optoelectronics technology.

Method used

A polycrystalline silicon deposition process combined with a polycrystalline silicon thermal oxidation process is used to control the sealing position at the top of the pores by forming a polycrystalline silicon layer in an asymmetric deep trench and gradually closing the opening. This includes etching the polycrystalline silicon layer and performing thermal oxidation to form a silicon oxide layer to seal the opening.

Benefits of technology

It effectively controls the sealing position at the top of the pore, solves the filling problem of asymmetric trenches with large aspect ratios, reduces filling costs, and can be widely used in the production of silicon photonics technology and MEMS products.

✦ Generated by Eureka AI based on patent content.

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Abstract

The application provides a filling method of asymmetric large-depth-width-ratio trench and a preparation method of semiconductor device, which comprises the following steps: 1) etching an asymmetric deep trench in a silicon substrate; 2) forming a hard mask layer, and performing a first thermal oxidation process to generate a first silicon oxide layer; 3) forming a polysilicon layer, and the polysilicon layer forms a first sealing part above the opening of the asymmetric deep trench; 4) etching the polysilicon layer to form an opening; and 5) performing a second thermal oxidation process, and in the process of oxidizing the polysilicon layer to form a second silicon oxide layer, the opening is sealed to form a second sealing part based on volume change, so as to control the sealing height of the pores surrounded by the second silicon oxide layer. The application can effectively fill the asymmetric large-depth-width-ratio trench and control the top sealing position of the pores by only using the traditional polysilicon deposition process combined with the polysilicon thermal oxidation process, solves the problem of filling the asymmetric large-depth-width-ratio silicon trench which cannot be solved by more advanced equipment, and greatly reduces the filling cost.
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Citation Information

Patent Citations

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