Polysilicon Native Oxide Nitriding to Prevent Lateral Etching
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Solution Overview
Problem
The formation of native oxide on polysilicon layers during semiconductor manufacturing leads to lateral etching, causing fragmentary mask patterns and reducing the yield of semiconductor structures.
Innovation Solution
Convert native oxide into a silicon oxynitride layer through nitriding treatment, which reduces the etching rate and prevents lateral etching, ensuring pattern integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If native oxide is removed by HF solution and then deionized water, then the native oxide is removed, but the surface of the polysilicon layer is oxidized again and native oxide is formed again
Solution Approach 1:
The patent changes the chemical composition parameter of the oxide layer by introducing nitrogen to convert silicon dioxide (native oxide) into silicon oxynitride. This parameter change transforms the material properties, making it resistant to lateral etching while maintaining surface coverage, thus preventing pattern fragmentation and improving both manufacturing precision and reliability
Solution Approach 2:
The patent converts the harmful native oxide layer, which causes lateral etching and pattern fragmentation, into a beneficial silicon oxynitride layer through nitriding treatment. This converted layer maintains the protective coverage function while eliminating the harmful lateral etching effect, thereby improving yield and pattern integrity
2Manufacturing precision
If nitriding treatment is performed to convert native oxide into silicon oxynitride layer, then lateral etching is prevented and pattern integrity is maintained, but additional process step is required
Solution Approach 1:
The nitriding treatment is performed as a preliminary action before the etching process to convert the native oxide into silicon oxynitride in advance. This preliminary modification of the oxide layer ensures that when etching occurs subsequently, lateral etching is prevented and pattern integrity is maintained, justifying the additional process step by eliminating more complex pattern repair and rework operations
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
Enhances the accuracy and yield of semiconductor structures by maintaining pattern integrity and preventing fragmentary mask patterns.
Implementation Method 1
performing plasma ionization to a nitrogen-containing gas to from nitrogen-containing plasma, and then treating the surface of the native oxide by the nitrogen-containing plasma
Implementation Method 2
performing a nitriding treatment to the native oxide, to nitrogenize the native oxide into a silicon oxynitride layer
Data Source
AI summary
A method for manufacturing a semiconductor includes: providing a substrate; forming a polysilicon layer on the substrate, a surface, away from the substrate, of the polysilicon layer having a native oxide; and performing a nitriding treatment to the native oxide, to nitrogenize the native oxide into a silicon oxynitride layer. The native oxide is nitrogenized into the silicon oxynitride layer.