Polymerizable Ester Compounds for ArF Lithography Resolution
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Solution Overview
Problem
Existing ArF excimer laser lithography resist materials face challenges in forming fine patterns with less than 200 nm pitch, exhibiting insufficient rectangularity and significant surface and sidewall roughness, particularly due to line edge roughness (LER), which affects semiconductor device performance.
Innovation Solution
Development of polymerizable ester compounds with specific chemical structures that form polymers used in resist compositions, enhancing transparency, rigidity, and reactivity, thereby minimizing pattern edge roughness and maintaining high resolution when processed by photolithography, especially under immersion lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If prior art resist materials are used to form fine patterns with pitch less than 200 nm, then pattern formation is attempted, but line edge roughness becomes substantial and rectangularity is insufficient
Solution Approach 1:
The invention changes the chemical structure parameters of the base resin by introducing specific ester compounds with controlled molecular weight and functional group composition. This modifies the physical and chemical properties of the resist material to reduce line edge roughness while maintaining pattern formation capability at sub-200 nm pitches
Solution Approach 2:
The invention uses composite resin systems combining multiple ester compound types (acrylic and methacrylic esters with specific functional groups) to achieve synergistic effects that simultaneously improve pattern rectangularity, reduce surface roughness, and maintain etch resistance
2Object-generated harmful factors
If resin with relatively low molecular weight is used to achieve smooth pattern finish, then surface roughness is reduced, but other properties such as exposure dose dependency and pattern density dependency are substantially sacrificed
Solution Approach 1:
The invention optimizes the molecular weight parameter within a specific range and adjusts the functional group composition to achieve a balance where surface smoothness is improved while exposure dose dependency and pattern density dependency are maintained at acceptable levels
3Object-generated harmful factors
If photoacid generator capable of generating rather mobile acid is selected to achieve smooth pattern finish, then surface roughness is reduced, but mask fidelity and other properties are substantially sacrificed
Solution Approach 1:
The invention changes the base resin parameters to compensate for the effects of mobile acid generators, allowing the use of efficient photoacid generators while maintaining mask fidelity through optimized resin chemistry
4Manufacturing precision
If existing resist materials are used for ArF excimer laser lithography, then current pattern formation capability is maintained, but further miniaturization and higher resolution by immersion lithography are not accommodated
Solution Approach 1:
The invention optimizes multiple parameters of the base resin including molecular weight, functional group composition, and chemical structure to enable the resist material to accommodate further miniaturization and achieve higher resolution in immersion lithography processes
Solution Approach 2:
The invention develops composite resist formulations with optimized base resin compositions that provide the necessary properties for both current ArF lithography and future immersion lithography applications, enabling technology roadmapping
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 polymerizable ester compounds improve exposure dose dependency, pattern density dependency, and mask fidelity while reducing pattern edge roughness, enabling precise micropatterning and accommodating further miniaturization in ArF excimer laser lithography.
Implementation Method 1
polymerizable ester compounds... when processed by photolithography using high-energy radiation such as ArF excimer laser radiation as a light source
Implementation Method 2
chemically amplified resist compositions... high sensitivity sufficient to minimize the burden to expensive optical materials
Data Source
AI summary
Polymerizable ester compounds having formula (1) are novel wherein R1 is H, F, methyl or trifluoromethyl, R2 is an acid labile group, Aa is a divalent hydrocarbon group which may be separated by —O— or —C(═O)—, and k1 is 0 or 1. They are useful as monomers to produce polymers which are transparent to radiation ≦500 nm. Radiation-sensitive resist compositions comprising the polymers as base resin exhibit excellent developed properties.