Manufacturing method of U-shaped groove

By first etching the active area in the length direction and then etching the organic bottom layer in the vertical direction to form a U-shaped groove in U-trench manufacturing, the problems of poor U-trench morphology and small process window are solved, and the effect of simplifying the process and improving the morphology is achieved.

CN118969615BActive Publication Date: 2025-10-03SHANGHAI HUALI INTEGRATED CIRCUIT CORP
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Patent Information

Application Number
CN202410814657.5
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2024-06-21
Publication Date
2025-10-03
Estimated Expiration
2044-06-21

AI Technical Summary

Technical Problem

In the existing U-trench manufacturing method, the U-trench morphology is poor and the process window is small. There are problems with the bell-mouth morphology and polymer residue, which makes the process steps complicated and difficult to miniaturize.

Method used

The first trench is formed by etching parallel to the length direction of the active area, and then the second trench is formed by etching the organic bottom layer in the vertical direction. The third etching is performed using the organic bottom layer pattern as a mask to form a U-shaped trench, which simplifies the process steps and improves the morphology.

Benefits of technology

The process window is improved, the bell-mouth morphology is avoided, the process steps are simplified, the number of hard mask layers is reduced, and the controllability and efficiency of the process are enhanced.

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Abstract

The present invention discloses a method for manufacturing a U-shaped groove, comprising: providing a semiconductor substrate on which field oxide is formed, wherein in a first region, the field oxide is used to isolate parallel-arranged first active regions. Forming a hard mask layer in the first region. Performing a first patterned etching on the hard mask layer to form a first groove and a first hard mask layer strip. The first groove is located directly above the first active region and exposes the top surface of the first active region. Applying an organic bottom layer. Performing a second patterned etching on the organic bottom layer to form an organic bottom layer pattern having a second groove, wherein the length directions of the first and second grooves are perpendicular, the second groove has a first overlapping region that overlaps with the first groove, and the top surface of the first active region in the first overlapping region is exposed. Performing a third etching on the semiconductor substrate using the organic bottom layer pattern as a mask to form a U-shaped groove in the first overlapping region. The present invention can increase the process window, improve the morphology of the U-shaped groove, and simplify the process steps.
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