Chemically Amplified Resist Composition for EUV Lithography
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Solution Overview
Problem
Current positive resist compositions face challenges in achieving high sensitivity, resolution, and etching resistance, particularly in advanced lithography processes such as EUV exposure, where traditional resins like novolak polymers are difficult to control and have low sensitivity due to high acceleration voltages, leading to decreased productivity and pattern misalignment issues.
Innovation Solution
A chemically amplified positive resist composition featuring a polymer with phenolic hydroxide groups substituted by acid labile groups, such as 1,2,3-indanyl, 1,2-acenaphthenyl, or 4,5-acephenanthrenyl groups, which improves sensitivity, resolution, and etching resistance by increasing carbon density and absorption, particularly using hydroxy styrene and hydroxy vinyl naphthalene units with specific molecular weight ranges and acid labile group substitutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acceleration voltage is increased to improve resolution and size controlling, then degree of resolution and contrast are improved, but sensitivity of resist is decreased
Solution Approach 1:
The patent changes the chemical composition parameters of the resist by introducing specific polymer structures with phenolic hydroxide groups and acid labile groups. This chemical parameter change enables the resist to maintain high sensitivity even at higher acceleration voltages (10-100 keV), resolving the contradiction between resolution and sensitivity by modifying the resist's chemical response to electron beam exposure.
Solution Approach 2:
The patent uses composite polymer structures combining phenolic hydroxide groups with acid labile groups (such as carboxylic acid groups, ester groups, or carbonate groups). This composite material approach creates a resist system that simultaneously achieves high sensitivity through chemical amplification and high resolution through controlled etching resistance, even at elevated acceleration voltages.
2Manufacturing precision
If acceleration voltage is increased to improve size controlling, then size misalignment is reduced, but productivity is decreased due to lower sensitivity
Solution Approach 1:
By modifying the resist's chemical parameters to include acid labile groups that undergo controlled decomposition and crosslinking reactions, the patent enables high size controlling precision at higher acceleration voltages while maintaining fast exposure speeds. The chemical amplification effect compensates for reduced sensitivity, preserving productivity.
3Measurement precision
If resist thickness is reduced to prevent pattern fall, then resolution is improved, but etching resistance becomes insufficient
Solution Approach 1:
The patent employs composite polymer structures where phenolic hydroxide groups provide etching resistance through their carbon-rich aromatic structures, while acid labile groups enable controlled solubility changes during development. This composite approach allows thin film resist to maintain both high resolution and sufficient etching resistance.
Solution Approach 2:
The patent applies local quality changes by introducing acid labile groups at specific positions within the polymer structure. These groups are strategically placed to provide controlled decomposition and crosslinking behavior during exposure and development, enabling thin resist films to achieve adequate etching resistance in critical regions while maintaining overall thinness for high resolution.
4Strength
If novolak polymer is used to achieve good etching resistance, then etching resistance is improved, but molecular weight and degree of dispersion become difficult to control
Solution Approach 1:
The patent changes the synthesis parameters and molecular structure of the polymer by using phenolic hydroxide groups with acid labile groups instead of traditional novolak structures. This enables precise control of molecular weight and polydispersity index through controlled polymerization reactions, while maintaining good etching resistance through the phenolic aromatic structures.
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 resist composition exhibits high sensitivity, resolution, and excellent etching resistance, enabling precise pattern configuration and improved productivity in advanced lithography processes, particularly suitable for VLSI manufacturing and EUV exposure.
Implementation Method 1
a chemically amplified positive resist composition is being studied
Data Source
AI summary
The present invention provides a polymer suitable as a base resin for a positive resist composition, especially for a chemically amplified positive resist composition, having a high sensitivity, a high degree of resolution, a good pattern configuration after exposure, and in addition an excellent etching resistance; a positive resist composition using the polymer; and a patterning process.The positive resist composition of the present invention is characterized in that it contains at least, as a base resin, a polymer whose hydrogen atom of a phenolic hydroxide group is substituted by an acid labile group represented by the following general formula (1).