Semiconductor Sidewall Pattern Formation via Dry Etching
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Solution Overview
Problem
The miniaturization of semiconductor devices poses a challenge in forming patterns that exceed the exposure resolution limit in lithography methods, as conventional methods face issues with pattern collapse, increased process complexity, and defects due to wet etching and surface tension-related stress.
Innovation Solution
A method involving the formation of mask material films and resist patterns on semiconductor substrates, followed by etchback and dry etching processes to create sidewall patterns, allowing for pattern transfer to the workpiece film while minimizing process steps and avoiding wet etching, which reduces stress and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet etching is used to etch the workpiece film, then the etching process can be performed, but pattern collapse occurs and defects are generated due to surface tension-related stress
Solution Approach 1:
The patent replaces wet etching (liquid-based) with dry etching (gas-based plasma process). This substitution eliminates the surface tension-related stress that causes pattern collapse in wet etching, while maintaining effective etching capability through plasma chemistry. The dry etching process removes the harmful mechanical stress factor while preserving the etching function.
Solution Approach 2:
The patent changes the etching medium from liquid (wet etching) to gas (dry etching with plasma). This parameter change fundamentally alters the stress characteristics of the etching process, eliminating surface tension effects that cause pattern collapse while maintaining etching effectiveness through controlled plasma reactions.
2Manufacturing precision
If conventional multi-step processes are used to form sidewall patterns, then the pattern can be formed, but process complexity increases and variations occur
Solution Approach 1:
The patent merges multiple separate process steps into a single integrated dry etching process. Instead of performing wet etching, sidewall formation, and pattern transfer as separate steps, the invention accomplishes all these functions in one dry etching step using the resist pattern as both the core material and sidewall definition, thereby reducing process complexity while maintaining manufacturing precision.
Solution Approach 2:
The resist pattern serves multiple functions simultaneously: it acts as the core material definition, the sidewall pattern template, and the mask for pattern transfer. This multi-functionality eliminates the need for separate sidewall formation processes and reduces the overall number of steps required to achieve the desired sidewall pattern structure.
3Measurement precision
If high-resolution resist materials are used, then pattern resolution is improved, but pattern collapse occurs during processing
Solution Approach 1:
The patent replaces wet etching with dry etching to eliminate surface tension stress that causes pattern collapse. This allows high-resolution resist patterns to be processed without the mechanical stress that would otherwise cause collapse, preserving both the high resolution and pattern stability.
Solution Approach 2:
The patent uses the resist pattern itself as the core material and forms sidewalls directly on it through dry etching, eliminating the need for separate core material layers. This segmentation approach maintains the integrity of high-resolution resist patterns by avoiding additional processing steps that could introduce stress or damage.
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 effectively prevents pattern collapse, reduces process variations, enhances yield, and allows for the use of high-resolution resist materials by processing from core material patterns to the workpiece film using dry etching with low-aspect-ratio sidewall patterns as masks.
Implementation Method 1
the interlayer is etched by an etchant while using the silicon nitride film as a mask
Implementation Method 2
the bottom resist layer is anisotropically-etched by using oxygen plasma
Data Source
AI summary
A method of manufacturing a semiconductor device according to one embodiment, includes: forming a first mask material film on a workpiece film formed on a semiconductor substrate; forming a resist pattern on the first mask material film; forming a second mask material film having a desired film thickness on the first mask material film so as to cover the resist pattern; carrying out etchback of the second mask material film so as to expose the resist pattern and the first mask material film; processing the resist pattern and the first mask material film simultaneously which are exposed, while leaving the second mask material film of which etchback is carried out; and processing the workpiece film which exposes under the first mask material film.