Silicon Resist Underlayer Composition for Wet-Etchable Lithography
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in removing resist underlayer films without damaging the substrate, particularly during dry etching, and require compositions that can be easily peeled and exhibit residue removability.
Innovation Solution
A silicon-containing resist underlayer film-forming composition using a hydrolysis condensate of a hydrolyzable silane mixture with specific structures, such as a succinic anhydride skeleton, allowing for both dry and wet etching processes, enhancing residue removability and storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hard mask containing metal elements (e.g., silicon or titanium) is used as the underlayer film, then the antireflection effect is achieved, but the removal of the hard mask by dry etching causes significant reduction in the thickness of the photoresist
Solution Approach 1:
The patent changes the chemical composition parameters of the underlayer film by using a silane-based organic composition instead of inorganic hard masks. This allows the underlayer to maintain antireflection properties while becoming chemically removable by wet etching processes, thereby preserving photoresist thickness during removal operations.
Solution Approach 2:
The silane-based underlayer film acts as an intermediary material that provides the necessary antireflection function while introducing chemical functionality (silane groups) that enables selective removal by wet etching. This intermediary composition bridges the gap between optical requirements and removable structure requirements.
2Object-generated harmful factors
If dry etching or ashing process is used for removal of mask residue, then the mask residue is removed, but the substrate is damaged
Solution Approach 1:
The patent replaces the mechanical/physical removal process (dry etching or ashing) with a chemical removal process (wet etching). The silane-based underlayer film is designed to be selectively removed by wet etching agents, thereby eliminating substrate damage associated with aggressive dry etching or ashing processes.
Solution Approach 2:
The patent changes the removal mechanism from physical (dry etching/ashing) to chemical (wet etching) by incorporating hydrolyzable silane groups in the underlayer composition. This parameter change in removal methodology eliminates substrate damage while maintaining effective mask residue removal.
3Ease of operation
If a silane-based composition is used for the underlayer film, then the film can be easily removed by wet etching, but the storage stability of the composition is reduced
Solution Approach 1:
The patent optimizes the molecular structure parameters of the silane compounds and adjusts the composition ratios to achieve a balance between storage stability and wet etching removability. By carefully controlling the silane structure and composition, the film maintains stability during storage while remaining removable by wet etching processes.
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 easy removal of mask residues with minimal substrate damage, improving the efficiency and reliability of semiconductor device production.
Implementation Method 1
a hydrolysis condensate of a hydrolyzable silane mixture
Data Source
AI summary
R1aR2bSi(R3)4-(a+b) (1)A composition for a silicon-containing resist underlying film and for forming a resist underlying film that can be removed by a conventional method employing dry etching, but also by a method employing wet etching using a chemical liquid in a step for processing a semiconductor substrate or the like; and a composition for forming a resist underlying film for lithography and for forming a resist underlying film that has excellent storage stability and produces less residue in a dry etching step. A composition for forming a resist underlying film, the composition including a hydrolysis condensate of a hydrolysable silane mixture containing an alkyltrialkoxy silane and a hydrolysable silane of formula (1), wherein the contained amount of the alkyltrialkoxy silane in the mixture is 0 mol % or more but less than 40 mol % with respect to the total amount by mole of all of the hydrolysable silane contained in the mixture.