Ethyl Lactate Resist Composition Stability
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Solution Overview
Problem
Resist compositions dissolved in organic solvents containing ethyl lactate suffer from deterioration of sensitivity over time, leading to poor lithographic characteristics, and existing methods to address this issue, such as adding organic base compounds, are insufficient.
Innovation Solution
A resist composition is formulated with an organic solvent containing ethyl lactate, incorporating a resin component that exhibits changeable alkali solubility under acid action, an acid generator, an amine, and acetic acid, which together improve sensitivity stability and lithographic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ethyl lactate is used as the organic solvent in the resist composition, then the resist composition can be prepared with good initial sensitivity, but the sensitivity deteriorates over time leading to poor lithographic characteristics
Solution Approach 1:
The patent applies preliminary action by adding specific basic compounds (amines with pKa 6-11) to the resist composition before storage. These compounds proactively neutralize acidic degradation products that form during storage, preventing sensitivity deterioration before it occurs. The basic compounds are selected and dosed in advance to counteract the known degradation pathway of ethyl lactate-based resist compositions over time.
2Reliability
If conventional organic base compounds are added to suppress sensitivity deterioration, then some sensitivity stability is improved, but the effect is insufficient and lithographic characteristics remain poor
Solution Approach 1:
The patent applies parameter changes by specifically selecting basic compounds with pKa values in the range of 6-11, which is a narrow and optimized range. This parameter optimization ensures the basic compounds are sufficiently basic to neutralize degradation products but not so basic as to cause other issues. The patent also optimizes the amount of basic compound added (0.01-5 wt%) to achieve the right balance between suppressing degradation and maintaining lithographic performance.
Solution Approach 2:
The patent applies composite materials by combining ethyl lactate-based resist composition with specifically selected basic compounds (amines or amide compounds). This creates a composite system where the basic compound component works synergistically with the resist matrix to provide both the original sensitivity and long-term stability. The composite formulation addresses both the solvent-based degradation issue and maintains positive lithographic characteristics.
3Manufacturing precision
If the resist composition is formulated for high initial sensitivity, then good lithographic characteristics are achieved initially, but sensitivity deteriorates with storage time
Solution Approach 1:
The patent applies preliminary action by incorporating basic compounds into the resist formulation before storage. This preliminary protective action prevents the chemical degradation that would otherwise occur during storage, thereby maintaining both the high initial sensitivity and the lithographic characteristics throughout the storage period. The basic compounds are pre-positioned to neutralize any acidic degradation products that may form.
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 proposed composition effectively suppresses sensitivity deterioration and maintains required lithographic characteristics, enabling the formation of high-quality resist patterns.
Implementation Method 1
an acid generator component (B) which generates an acid upon exposure
Implementation Method 2
an amine (D) and acetic acid
Data Source
AI summary
The present invention provides a resist composition prepared by dissolving components in an organic solvent containing ethyl lactate, which suppresses deterioration of sensitivity with time and also has required lithographic characteristics, and a method for forming a resist pattern. The resist composition is prepared by dissolving a resin component (A) which exhibits changeable alkali solubility under an action of an acid, an acid generator component (B) which generates an acid upon exposure, an amine (D) and acetic acid in an organic solvent (S) containing ethyl lactate.