Lithography Underlayer Film Compound for Etching Resistance
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Solution Overview
Problem
Current materials for forming underlayer films in lithography lack high solvent solubility for wet processes like spin coating or screen printing, while also requiring high heat resistance and etching resistance, which are essential for advanced semiconductor manufacturing.
Innovation Solution
A compound with a specific structure, represented by formula (1), is used to create a resin for forming underlayer films that can be applied in wet processes, offering high heat resistance, etching resistance, and excellent adhesiveness, along with a method for purifying the compound using an acidic aqueous solution and organic solvent extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional materials are used for underlayer films, then etching resistance can be achieved, but solvent solubility for wet processes is insufficient
Solution Approach 1:
The patent uses a copolymer composed of a naphthalene formaldehyde polymer and a vinyl aromatic compound polymer. This composite structure combines the etching resistance of the naphthalene formaldehyde polymer with the solvent solubility of the vinyl aromatic compound polymer, resolving the contradiction between these two properties.
2Manufacturing precision
If the resist film is made thinner to achieve finer patterns, then resolution improves, but the film thickness becomes insufficient for substrate processing
Solution Approach 1:
The patent divides the protective function into two separate layers: a thin resist film for pattern formation and a thicker underlayer film for substrate protection. This segmentation allows the resist film to be thin enough for fine patterns while the underlayer provides sufficient thickness for substrate processing.
3Reliability
If amorphous carbon underlayer film is used for high etching resistance, then etching resistance improves, but process complexity increases due to CVD requirements
Solution Approach 1:
The patent replaces the CVD process (chemical vapor deposition) with a wet coating process. The copolymer material can be dissolved in solvents and applied by spin coating or dip coating, substituting the complex CVD equipment and process with simpler, more widely available wet coating techniques while maintaining etching resistance.
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 compound enables the formation of underlayer films that maintain integrity during high-temperature baking and exhibit superior etching resistance, facilitating the creation of finer patterns with reduced pattern collapse, and the purification method effectively reduces metal content, ensuring high purity.
Implementation Method 1
bringing the solution into contact with an acidic aqueous solution for extraction to thereby transfer a metal content included in the solution (A) including the compound or the resin and the organic solvent to an aqueous phase
Implementation Method 2
separating an organic phase and the aqueous phase
Data Source
AI summary
The compound according to the present invention is represented by a specific formula. The compound according to the present invention has a structure according to the specific formula, and therefore can be applied to a wet process and is excellent in heat resistance and etching resistance. In addition, the compound according to the present invention has such a specific structure, and therefore has a high heat resistance, a relatively high carbon concentration, a relatively low oxygen concentration and also a high solvent solubility. Therefore, the compound according to the present invention can be used to form an underlayer film whose degradation is suppressed at high-temperature baking and which is also excellent in etching resistance to oxygen plasma etching or the like. Furthermore, the compound is also excellent in adhesiveness with a resist layer and therefore can form an excellent resist pattern.