Lactone-Containing Acrylate Copolymer Resist for Double Patterning Stability
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Solution Overview
Problem
In double patterning processes for semiconductor and liquid crystal display element production, positive-type chemically amplified resist compositions are prone to damage during the second patterning step, leading to shape changes or destruction of the first resist pattern, especially when using alkali developing solutions, and conventional alcohol-based solvents result in poor solubility and long-term stability issues.
Innovation Solution
A resist composition containing a base component with a copolymer that exhibits increased polarity under acid action, including a structural unit derived from an acrylate ester with a lactone-containing cyclic group, dissolved in an organic solvent with an alcohol-based solvent, which generates acid upon exposure to form a resist pattern with improved solubility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a positive-type chemically amplified resist composition is used in double patterning processes, then lithography properties and resolution are improved, but the first resist pattern is damaged during the second patterning step
Solution Approach 1:
The patent changes the chemical parameters of the resist composition by incorporating specific copolymers with lactone-containing cyclic groups and using alcohol-based solvents instead of conventional alkali solvents. This parameter change allows the resist to maintain its structural integrity during double patterning while preserving lithography performance.
Solution Approach 2:
The patent uses a composite resist composition comprising multiple components: copolymer (A1) with lactone-containing cyclic groups, copolymer (A2) with acid-degradable groups, and copolymer (A3) with polar groups. This composite structure provides both the necessary lithography properties and enhanced pattern stability during sequential processing.
2Ease of operation
If conventional alcohol-based solvents are used in resist composition, then solubility is improved, but long-term stability deteriorates
Solution Approach 1:
The patent modifies the solvent system by selecting specific alcohol-based solvents with controlled polarity and solvating power. The solvent parameters are optimized to achieve adequate solubility of the copolymer components while maintaining long-term compositional stability of the resist formulation.
Solution Approach 2:
The patent assigns different functional roles to different copolymer components: copolymer (A1) with lactone groups provides solubility in alcohol-based solvents, while copolymers (A2) and (A3) provide structural stability and acid response. This local functional differentiation resolves the contradiction between solubility and stability.
3Manufacturing precision
If the wavelength of exposure light source is shortened for pattern miniaturization, then resolution is improved, but sensitivity of resist material deteriorates
Solution Approach 1:
The patent incorporates copolymer (A1) containing lactone-containing cyclic groups which exhibit enhanced transparency and reduced absorption in the deep ultraviolet region (193 nm and shorter wavelengths). This parameter change in the resin composition maintains sensitivity while enabling higher resolution patterning.
Solution Approach 2:
The acid generator component acts as an intermediary that amplifies the exposure signal. Upon exposure to short-wavelength light, the acid generator produces acid that triggers the solubility change in the copolymer components, thereby maintaining sensitivity even with reduced light absorption at shorter wavelengths.
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 enables the formation of patterns with minute dimensions and superior shape stability, maintaining lithography properties and long-term solubility, even with alcohol-based solvents, thus addressing the challenges of pattern damage and solubility issues in double patterning processes.
Implementation Method 1
an acid generator component (B) which generates acid upon exposure
Implementation Method 2
a copolymer (A1) that exhibits increased polarity under the action of acid
Data Source
AI summary
A resist composition containing a base component (A) which exhibits changed solubility in a developing solution under the action of acid, and an acid generator component (B) which generates acid upon exposure, dissolved in an organic solvent (S) which contains an alcohol-based solvent, wherein the base component (A) contains a copolymer (A1) that exhibits increased polarity under the action of acid, and the copolymer (A1) is a copolymer in which a structural unit (a2), which is derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom on the α-position may be substituted with a substituent, and includes a lactone-containing cyclic group, is dispersed uniformly within the copolymer molecule.