Semiconductor Mask Stack for Uniform Oblique Cross Etching
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Solution Overview
Problem
In semiconductor manufacturing, the existing method for forming obliquely crossed mask patterns often results in uneven etching holes due to the lower layer material being easily etched, leading to inconsistent dimensions and performance issues in the semiconductor device.
Innovation Solution
A method involving the sequential stacking of mask and buffer layers with specific etching selectivities greater than 1 to protect the lower layers during pattern formation, ensuring uniformity and consistency of etching holes by obliquely crossing the patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the lower layer material is easily etched while mask patterns are formed, then the mask patterns can be formed quickly, but the holes formed by crossing the two layers of mask patterns are uneven in dimension
Solution Approach 1:
A buffer layer is introduced as an intermediary between the lower layer material and the mask pattern. This buffer layer has specific etching selectivity characteristics that allow it to be etched at a controlled rate, protecting the lower layer material from excessive etching while enabling the mask pattern to be formed. The buffer layer acts as a mediator that balances the conflicting requirements of formation speed and dimension uniformity.
Solution Approach 2:
The etching selectivity parameter is carefully controlled by selecting appropriate materials for the buffer layer and lower layer material. By adjusting the etching selectivity of the buffer layer to the lower layer material, the process achieves optimal balance between productivity and manufacturing precision. This parameter optimization ensures that the lower layer material is not overly etched while maintaining efficient mask pattern formation.
2Reliability
If the etching selectivity of the buffer layer to the lower layer material is increased, then the lower layer material is better protected, but the etching process becomes more complex
Solution Approach 1:
The buffer layer serves as a protective intermediary that simplifies the overall etching process. Instead of using complex multi-step etching procedures or multiple protective layers, a single buffer layer with appropriate etching selectivity provides effective protection to the lower layer material. This intermediary approach reduces process complexity while maintaining high reliability of lower layer protection.
Solution Approach 2:
The buffer layer is formed from materials with specific composite properties that provide both protection and controlled etching characteristics. By selecting materials with appropriate etching selectivity ratios, the system achieves effective lower layer protection without requiring complex multi-material stacks or intricate process sequences, thereby maintaining process simplicity.
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
The method ensures uniform and consistent etching holes are formed, preventing performance issues in semiconductor devices by protecting the lower layers during the formation of obliquely crossed mask patterns.
Implementation Method 1
an etching selectivity of the second buffer layer to the first buffer layer is greater than 1
Data Source
AI summary
A method for manufacturing a semiconductor structure, comprising: forming a first mask layer, a first buffer layer, a second mask layer and a second buffer layer sequentially stacked from bottom to top; patterning the second buffer layer and the second mask layer; forming a first mask pattern on a side wall of a first pattern, the first mask pattern extending in a first direction; removing the second buffer layer and the second mask layer; forming a third mask layer, a third buffer layer, a fourth mask layer and a fourth buffer layer sequentially stacked form bottom to top; patterning the fourth buffer layer and the fourth mask layer; forming a second mask pattern on a side wall of a second pattern, the second mask pattern extending in a second direction; removing the fourth buffer layer and the fourth mask layer.