Chemically Amplified Resist Composition for High Resolution Lithography
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Solution Overview
Problem
Current resist materials face challenges in achieving high resolution and minimal edge roughness for fine pattern formation, particularly with increased accelerating voltage in electron beam lithography, where sensitivity and contrast are compromised due to acid diffusion and reduced dry etch resistance, leading to pattern collapse and dimensional errors.
Innovation Solution
A chemically amplified positive resist composition featuring a polymer with recurring units having an electron attractive acyl or alkoxycarbonyl group and an acid labile group, combined with an acid generator, to enhance alkaline dissolution contrast and suppress acid diffusion, resulting in improved resolution and minimal edge roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the accelerating voltage is increased to improve resolution and reduce scattering, then the resolution and dimensional control are improved, but the sensitivity of the resist film decreases
Solution Approach 1:
The patent modifies the chemical composition parameters of the resist film by incorporating specific polymer structures with carboxyl groups and designing acid generators with appropriate pKa values to optimize the chemical amplification process, thereby improving sensitivity without sacrificing resolution
Solution Approach 2:
The patent creates a composite resist system combining specific polymers (such as polyhydroxystyrene derivatives) with acid generators and additives to achieve synergistic effects that simultaneously improve both resolution and sensitivity
2Manufacturing precision
If the resist film thickness is reduced to improve resolution and prevent pattern collapse, then the resolution is improved, but the dry etch resistance becomes insufficient
Solution Approach 1:
The patent optimizes the chemical composition and crosslinking density of the resist film to enhance etch resistance per unit thickness, allowing thinner films to maintain adequate mechanical strength and etch resistance
Solution Approach 2:
The patent introduces functional groups and crosslinking structures at specific locations within the resist film to locally enhance etch resistance where needed while maintaining overall film thinness for high resolution
3Productivity
If the acid diffusion is increased to improve sensitivity through chemical amplification, then the sensitivity is improved, but the resolution and edge roughness deteriorate
Solution Approach 1:
The patent carefully controls the pKa value of the acid generator and the basicity of the quencher to optimize acid diffusion distance, achieving sufficient chemical amplification while limiting excessive diffusion that would degrade resolution
Solution Approach 2:
The patent introduces basic compounds (quenchers) as intermediaries to control and limit acid diffusion, creating a balanced chemical amplification process that maintains both sensitivity and resolution
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 minimal edge roughness, effectively addressing the challenges of pattern formation in electron beam lithography and EUV lithography by maintaining high etch resistance and preventing pattern collapse.
Implementation Method 1
chemically amplified positive resist composition comprising the polymer and an acid generator
Implementation Method 2
suppress acid diffusion, resulting in improved resolution and minimal edge roughness
Implementation Method 3
chemically amplified positive resist composition
Data Source
AI summary
A positive resist composition comprising a polymer comprising recurring units having both an acyl or alkoxycarbonyl group and an acid labile group-substituted hydroxyl group exhibits a high contrast of alkaline dissolution rate before and after exposure, a high resolution, a good pattern profile and minimal edge roughness.