Polymer Compound for High-Resolution Resist Patterning
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Solution Overview
Problem
Current chemically amplified resist compositions for photomask processing face challenges in achieving high resolution and small line edge roughness (LER) due to inadequate control of acid diffusion, leading to issues with pattern profile stability and sensitivity, particularly when using fluorinated alkanesulfonic acids which cause deprotection reactions in unexposed areas.
Innovation Solution
A polymer compound with specific repeating units, including those that generate acids with controlled acidity, is introduced as a base resin in a positive resist composition, incorporating sulfonium or iodonium cations and acid-labile groups to manage acid diffusion and deprotection reactions, ensuring high resolution and rectangular pattern profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fluorinated alkanesulfonic acid is used as an acid generator, then sensitivity and resolution are improved, but acid diffusion increases causing deprotection reactions in unexposed areas
Solution Approach 1:
The patent changes the chemical structure of the acid generator from conventional fluorinated alkanesulfonic acid to a cycloaliphatic sulfonic acid with specific structural parameters (formula 1). This structural parameter change reduces the acid strength and diffusion capability while maintaining the ability to generate sufficient acid for deprotection in exposed areas, thereby improving resolution without causing unwanted deprotection in unexposed areas.
Solution Approach 2:
The patent introduces a polymer compound with specific repeating units (formulae 2 and 3) that have different local chemical environments. The repeating units contain acid-labile groups that are strategically positioned to be sensitive to the modified acid generator, creating a local quality difference where exposed areas undergo deprotection while unexposed areas remain stable.
2Manufacturing precision
If acid diffusion is reduced to improve resolution, then LER is reduced, but pattern profile stability deteriorates due to insufficient deprotection
Solution Approach 1:
The patent creates a composite system combining a specifically structured polymer compound (with repeating units of formulae 2 and 3) and a cycloaliphatic sulfonic acid generator (formula 1). This composite material design ensures that the acid generator and polymer work synergistically to achieve controlled acid diffusion that reduces LER while maintaining sufficient deprotection for pattern profile stability.
Solution Approach 2:
The patent optimizes the structural parameters of the polymer compound, specifically the ratios and structures of repeating units (formulae 2 and 3), to balance acid diffusion control with deprotection efficiency. By adjusting these compositional parameters, the patent achieves a state where LER is minimized while pattern profile stability is maintained through adequate deprotection in exposed regions.
3Ease of manufacture
If conventional base resin is used, then solubility in organic solvent is maintained, but pattern rectangularity and resolution deteriorate due to uncontrolled acid diffusion
Solution Approach 1:
The patent modifies the base resin by incorporating specific repeating units (formulae 2 and 3) that create local chemical environments with controlled acid-labile groups. This local quality modification allows the resin to maintain overall solubility in organic solvents while creating localized regions that respond selectively to the acid generator, improving pattern rectangularity and resolution.
Solution Approach 2:
The patent develops a composite polymer compound that integrates conventional solubilizing groups with specifically designed acid-labile repeating units (formulae 2 and 3). This composite structure maintains the ease of manufacture through good solubility while introducing functional regions that control acid diffusion and improve pattern rectangularity 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 polymer compound enables the formation of resist films with extremely high resolution, small LER, and excellent pattern rectangularity, effectively addressing the limitations of existing compositions by controlling acid diffusion and deprotection, and is suitable for high-energy beam exposure processes.
Implementation Method 1
a repeating unit (1c) shown in Formula (1c), and at least one repeating unit selected from a repeating unit (2) shown in Formula (2) and a repeating unit (3) shown in Formula (3), wherein the repeating unit (1c) generates an acid by exposure
Implementation Method 2
incorporating sulfonium or iodonium cations and acid-labile groups to manage acid diffusion and deprotection reactions
Implementation Method 3
control of acid diffusion, which significantly affects resolution of the chemically amplified resist film
Data Source
AI summary
A polymer compound containing a repeating unit shown by the formula (1c) and one or more repeating units selected from a repeating unit shown by the formula (2) and a repeating unit shown by the formula (3),wherein Mb+ represents a sulfonium cation shown by the formula (a) or an iodonium cation shown by the formula (b),This polymer compound is suitable as a base resin of a resist composition capable of forming a resist film that allows pattern formation with extremely high resolution, small LER, and excellent rectangularity.