Lithography Underlayer Film Material 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.
Innovation Solution
A naphthol derivative with a specified structure, represented by general formulas (1) and (2), is used to create a material for forming underlayer films that includes a compound or resin with high heat resistance, high carbon concentration, and low oxygen concentration, allowing for excellent adhesiveness and etching resistance.
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 modifies the chemical structure parameters of the resin by introducing specific substituent groups (fluorine atoms, sulfonic acid groups, carboxylic acid groups) at controlled positions and concentrations. This changes the molecular properties to achieve both high etching resistance and improved solvent solubility simultaneously, resolving the contradiction between these two properties.
Solution Approach 2:
The invention creates a composite resin structure by combining multiple functional units within the same polymer chain: a backbone providing etching resistance, and side chains or substituents providing solvent compatibility. This composite approach allows the material to exhibit both high etching resistance and good solubility in wet processing solvents.
2Manufacturing precision
If the resist film is made thinner to achieve finer patterns, then resolution improves, but 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 definition and a thicker underlayer film for substrate protection and etching resistance. This segmentation allows the resist to be thin enough for high resolution while the underlayer provides sufficient thickness for mechanical support and processing protection.
Solution Approach 2:
The underlayer film acts as an intermediary between the thin resist pattern and the substrate. It provides the necessary mechanical strength and etching resistance that the thin resist cannot provide alone, while being compatible with the resist's patterning function. The underlayer mediates between the conflicting requirements of thin film resolution and sufficient protection.
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 physical vapor deposition process (CVD) with a chemical solution-based spin coating process. Instead of using methane gas and CVD equipment to form carbon-based underlayer, the invention uses a chemically synthesized resin that can be dissolved in solvents and applied by simple spin coating, eliminating the need for complex CVD equipment and processes while maintaining etching resistance.
Solution Approach 2:
The invention changes the material state from gaseous precursors (methane for CVD) to liquid solution form (resin in solvent). This parameter change allows the underlayer to be deposited by wet processing methods instead of vacuum-based CVD, simplifying the manufacturing process while achieving comparable or superior etching resistance through molecular structure design.
Data Source
AI summary
Material for forming an underlayer film for lithography, which has a high carbon concentration, a low oxygen concentration, a relatively high heat resistance and also a relatively high solvent solubility, and which can be applied to a wet process is disclosed. Material for forming an underlayer film for lithography contains a compound represented by general formula (1).