Radiation-Sensitive Resin Composition for Immersion Lithography
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Solution Overview
Problem
In liquid immersion exposure processes, acid generators are eluted from resist films when in contact with immersion liquids like water, leading to pattern defects, insufficient resolution, and dissolution residues during development, particularly due to low receding contact angles and inadequate solubility of resin components.
Innovation Solution
A radiation-sensitive resin composition comprising a first polymer with a specific repeating unit, a second polymer with an acid labile group, and a radiation-sensitive acid generator, which suppresses elution and development defects by maintaining a high receding contact angle and ensuring proper solubility in developers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If liquid immersion exposure process is used to increase resolution, then resolution is improved, but acid generator elution occurs causing pattern defects
Solution Approach 1:
The patent introduces a specific resin composition as an intermediary layer between the acid generator and the liquid immersion exposure environment. This resin composition acts as a barrier that prevents acid generator elution while allowing the liquid to pass through for exposure, thus resolving the contradiction between achieving high resolution through liquid immersion and preventing pattern defects from acid generator elution
Solution Approach 2:
The patent changes the chemical and physical parameters of the resin composition, specifically controlling the receding contact angle to 20° or more and adjusting the solubility parameters. These parameter changes create a resin layer that is resistant to liquid immersion while maintaining proper development characteristics, thereby preventing acid generator elution and pattern defects while preserving resolution improvement
2Reliability
If receding contact angle is increased to prevent elution, then elution is reduced, but development defects may increase
Solution Approach 1:
The patent precisely controls the receding contact angle parameter within a specific range (20° or more) and adjusts solubility parameters to achieve optimal balance. By carefully tuning these parameters, the resin composition achieves sufficient elution resistance while maintaining proper development characteristics, preventing both elution-related and development-related defects
Solution Approach 2:
The patent uses a composite resin composition containing multiple functional components including polymers with specific solubility characteristics and surface property controllers. This composite material structure allows simultaneous optimization of elution resistance and development performance, resolving the contradiction between preventing elution and avoiding development defects
3Ease of manufacture
If conventional resin composition is used, then ease of manufacture is maintained, but dissolution residues occur during development
Solution Approach 1:
The patent modifies key parameters of the resin composition including solubility parameters and molecular weight distribution while maintaining a formulation approach that is relatively simple to manufacture. These parameter changes enable the resin to dissolve cleanly during development without leaving residues, while the manufacturing process remains practical and scalable
Solution Approach 2:
The patent replaces complex multi-component systems with a simplified resin composition that achieves the desired development clarity through careful selection of polymer chemistry and solubility characteristics. This substitution maintains ease of manufacture while eliminating dissolution residues through intrinsic material properties rather than complex processing
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 composition enables the formation of microfine photoresist films with excellent depth of focus, reduced liquid immersion exposure component elution, and minimized development defects, suitable for future fine lithography applications.
Implementation Method 1
an acid generator (C) which generates acid upon exposure to radiation
Implementation Method 2
a second polymer (B) which comprises an acid labile group and is dissociated by an action of acid so that alkali solubility is given by dissociation of the acid labile group
Implementation Method 3
a liquid refractive-index medium (liquid for the liquid immersion exposure process) such as pure water or a fluorine-containing inert liquid, which has a predetermined thickness, is interposed between a lens and a resist film
Data Source
AI summary
The radiation-sensitive resin composition includes a first polymer, a second polymer and a radiation sensitive acid generator. The first polymer includes a repeating unit represented by formula (1). The second polymer includes an acid labile group and is dissociated by an action of acid so that alkali solubility is given by dissociation of said acid labile group. R1 represents a hydrogen atom, a methyl group or a trifluoromethyl group. R2 represents a single bond or a divalent linear, branched or cyclic, saturated or unsaturated hydrocarbon group having 1-20 carbon atoms. X represents a fluorine atom-substituted methylene group or a linear or branched fluoroalkylene group having 2-20 carbon atoms. R3 represents a hydrogen atom or a monovalent organic group.