Silicon Resist Underlayer Composition Balancing Wet Etch and Lithography
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Solution Overview
Problem
In semiconductor device processing, dry etching and ashing methods cause significant damage to substrates, and there is a need for a composition that can form a silicon-containing resist underlayer film that can be removed by both dry etching and wet etching methods while maintaining excellent lithography properties and achieving a high etching rate.
Innovation Solution
A composition comprising polysiloxane, a sulfonic acid compound or sulfuric acid, and a solvent, with optional components like a curing catalyst, nitric acid, and amine or hydroxide, which forms a resist underlayer film suitable for extreme ultraviolet lithography and can be removed using a wet etching method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dry etching method is used to remove the resist underlayer film, then the etching speed is fast, but the substrate is damaged significantly
Solution Approach 1:
The patent changes the chemical composition parameters of the resist underlayer film by incorporating specific polymers (polyhydroxystyrene, polyacrylic acid, polyacrylamide) and silicon compounds. This enables the film to be etched by wet etching methods at high speeds while reducing substrate damage compared to conventional dry etching approaches.
Solution Approach 2:
The patent replaces the physical/mechanical dry etching process with a chemical wet etching process. By formulating the resist underlayer film with specific chemical compositions that are highly etchable by wet etching solutions, the method achieves fast etching speeds while minimizing the mechanical damage associated with dry etching.
2Reliability
If a hard mask containing metal elements is used as the resist underlayer film, then the film provides good antireflection effect, but the composition differs significantly from the resist making removal difficult
Solution Approach 1:
The patent creates a resist underlayer film that serves multiple functions: it provides antireflection effect during lithography and is simultaneously etchable by wet etching methods. The film contains silicon compounds that contribute to antireflection properties while the polymer matrix enables easy removal by wet etching, eliminating the need for separate removal processes.
Solution Approach 2:
The patent uses composite materials consisting of polymer matrices (polyhydroxystyrene, polyacrylic acid, or polyacrylamide) combined with silicon compounds. This composite structure provides both the antireflection effect needed for lithography and the chemical etchability required for easy removal, resolving the contradiction between film performance and removal difficulty.
3Ease of operation
If the resist underlayer film is designed for easy wet etching removal, then the removal process is simplified, but the lithography properties may be compromised
Solution Approach 1:
The patent optimizes the chemical composition parameters of the resist underlayer film by selecting specific polymers and silicon compounds in controlled ratios. This formulation achieves both excellent wet etching removability and maintained lithography properties, including appropriate film thickness control and pattern fidelity during the lithography process.
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 composition enables the formation of a resist underlayer film with excellent lithography properties and high wet etching rates, allowing for effective removal by both dry and wet etching methods, addressing the damage issues associated with dry etching and enhancing miniaturization capabilities in semiconductor processing.
Implementation Method 1
a component [B]: at least one selected from the group consisting of a sulfonic acid compound and an acid having a pKa from −15.0 to 1.2
Data Source
AI summary
A composition for forming a silicon-containing resist underlayer film, the composition containing: a component of a polysiloxane; a component of at least one selected from the group consisting of a sulfonic acid compound and an acid having a pKa from −15.0 to 1.2; and a component of a solvent.