Semiconductor Trench Etching with Multi-Mask Depth Uniformity
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Solution Overview
Problem
Existing semiconductor manufacturing methods face challenges in achieving uniform trench depth across the semiconductor substrate, leading to reduced yield and reliability of the semiconductor devices.
Innovation Solution
The method involves using selective etching techniques with blank exposure and multiple masks to ensure uniform trench depth, followed by optimizing the division of regions based on etching depth distribution, thereby enhancing the uniformity and reliability of the semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional single-mask etching is used, then the manufacturing process is simple, but the trench depth uniformity across the substrate deteriorates
Solution Approach 1:
The etching process is divided into two sequential stages using two different masks. The first mask (photoresist pattern) defines the initial trench pattern, while the second mask (mandrel structure) controls the final trench depth. This segmentation allows independent optimization of pattern definition and depth control, resolving the contradiction between process simplicity and depth uniformity.
Solution Approach 2:
The first mask is formed and etching is performed preliminarily to create initial trenches. Then the second mask is formed on these trenches to control the final depth. This preliminary action sequence allows the process to achieve both the simplicity of a straightforward etching step and the precision of controlled depth uniformity through the intermediate mandrel structure.
2Manufacturing precision
If multi-region selective etching is implemented, then the trench depth uniformity is improved, but the device complexity increases
Solution Approach 1:
The second mask serves multiple functions: it acts as a depth control mandrel during etching, provides a structural framework for subsequent insulation film formation, and enables selective depth adjustment across different substrate regions. This multi-functionality reduces the need for separate processes, thereby limiting the increase in device complexity while achieving improved trench depth uniformity.
Solution Approach 2:
The substrate is divided into multiple regions with different etching depth requirements. The second mask is selectively positioned and etched to different depths in different regions, allowing local optimization of trench depth. This local quality approach improves overall trench depth uniformity across the substrate while managing complexity through region-specific control rather than global process complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the uniformity of trench depth, enhances the yield, and increases the reliability of semiconductor devices by addressing non-uniform etching issues.
Implementation Method 1
etching the semiconductor substrate in the first region using the first and second masks as a mask
Data Source
AI summary
A manufacturing method of a semiconductor device includes preparing a semiconductor substrate having an upper surface and a lower surface, forming a first mask having a plurality of openings on the upper surface divided into a first region and a second region, forming a second mask that exposes a portion of the first mask arranged in the first region and covers a portion arranged in the second region, etching the semiconductor substrate in the first region using the first mask and the second mask as a mask, removing the second mask, and etching the semiconductor substrate in the first region and the second region using the first mask as a mask.