Amorphous Carbon Dry Etching Sidewall Protection
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Solution Overview
Problem
Conventional dry etching methods for amorphous carbon layers in semiconductor fabrication often result in isotropic etching, leading to abnormal shapes like bowing and rough sidewalls, which complicates the formation of high-aspect-ratio patterns and dimensional accuracy.
Innovation Solution
A dry etching method using a plasma gas mixture of oxygen and alkylsilane, with an inorganic film as a mask, to form a sidewall protection film that suppresses side etching and maintains a smooth surface, thereby preventing dimensional displacement and abnormal etching shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dry etching methods using oxygen plasma are used to etch amorphous carbon layers, then etching can proceed, but isotropic etching occurs leading to bowing and rough sidewalls
Solution Approach 1:
The patent introduces a sidewall protection film as an intermediary layer between the amorphous carbon layer and the oxygen plasma. This protection film selectively prevents oxygen plasma from directly contacting the amorphous carbon sidewalls, thereby suppressing isotropic etching and maintaining vertical sidewall profiles while allowing controlled etching to proceed
Solution Approach 2:
The patent modifies the etching process parameters by introducing a dual-gas system (oxygen for etching, silane-based gas for protection film formation) and controlling their respective flow rates and timing. This parameter change enables selective formation of the protection film on sidewalls while maintaining etching capability in the horizontal direction
2Productivity
If oxygen plasma is used for etching amorphous carbon, then etching reaction occurs, but side etching increases causing dimensional displacement
Solution Approach 1:
The sidewall protection film acts as a mediator that selectively blocks oxygen plasma from attacking the amorphous carbon sidewalls. This allows the etching reaction to proceed efficiently in the desired direction while preventing unwanted side etching that would cause dimensional displacement
Solution Approach 2:
The protection film is formed locally only on the sidewalls of the amorphous carbon structures through selective deposition processes. This local quality change ensures that etching protection is applied precisely where needed (on sidewalls) without affecting the overall etching rate or pattern formation
3Ease of manufacture
If conventional etching methods are used, then the etching process can be completed, but the sidewall surface becomes rough and abnormal shapes form
Solution Approach 1:
The patent performs preliminary action by forming the sidewall protection film before the main etching process. This pre-formed protection layer prevents the formation of rough surfaces and abnormal shapes during etching, ensuring smooth sidewalls without complicating the overall manufacturing process
Solution Approach 2:
The protection film serves as an intermediary barrier that maintains surface smoothness during etching. By preventing direct contact between oxygen plasma and amorphous carbon sidewalls, it eliminates the mechanisms that would otherwise cause surface roughening and abnormal shape formation
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 effectively suppresses side etching and maintains a smooth sidewall surface, ensuring accurate and anisotropic etching of amorphous carbon layers, improving the formation of high-aspect-ratio patterns and dimensional precision.
Implementation Method 1
preparing a plasma gas by converting a dry etching agent into a plasma
Implementation Method 2
forming a sidewall protection film that suppresses side etching
Implementation Method 3
conducting plasma etching on the amorphous carbon film by using the plasma gas
Implementation Method 4
a dry etching agent containing at least oxygen and alkylsilane
Data Source
AI summary
A dry etching method provided to involve the steps of: (a) disposing a substrate within a chamber, the substrate having an amorphous carbon film; (b) preparing a plasma gas by converting a dry etching agent into a plasma, the dry etching agent containing at least oxygen and alkylsilane; and (c) conducting plasma etching on the amorphous carbon film by using the plasma gas and an inorganic film as a mask.