Resist Pattern Clarity via Segmented Development and Rinsing
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Solution Overview
Problem
Current methods for forming resist patterns using positive resist compositions leave room for improvement in clarity due to issues such as resist pattern collapse and the presence of residues, which affect the clarity of the obtained pattern.
Innovation Solution
A method involving a positive resist composition with specific fluorine-containing polymers and a rinsing liquid with a surface tension of 20.0 mN/m or less is used, including a monomer unit (A) and (B) with specific fluorine atom configurations, to inhibit resist pattern collapse and residues during the development and rinsing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional developer with surface tension of 17.0 mN/m or less is used to develop the resist film, then resist pattern collapse is inhibited, but the clarity of the resist pattern leaves room for improvement due to presence of residues
Solution Approach 1:
The development process is segmented into two distinct stages: first development using a developer with surface tension of 17.0 mN/m or less to prevent collapse, followed by a rinsing step using a rinsing liquid with surface tension of 20.0 mN/m or less to remove residues. This segmentation allows each step to be optimized for its specific function, resolving the contradiction between collapse inhibition and clarity improvement.
Solution Approach 2:
A rinsing liquid serving as an intermediary substance is introduced between the developer and the final resist pattern. This rinsing liquid, with surface tension of 20.0 mN/m or less, acts as a mediator that removes residues from the resist pattern after development, thereby improving clarity without affecting the collapse inhibition achieved during the development step.
2Manufacturing precision
If a rinsing step is added after development to improve clarity, then residues are reduced, but the process complexity increases
Solution Approach 1:
The rinsing liquid is specifically designed with a surface tension parameter of 20.0 mN/m or less, which is slightly higher than the developer's surface tension of 17.0 mN/m or less. This parameter change allows the rinsing liquid to effectively remove residues while maintaining compatibility with the resist pattern structure, achieving improved clarity with a relatively simple process addition.
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
This approach effectively inhibits resist pattern collapse and residues, enhancing the clarity of the resist pattern by using a fluorine-containing solvent for development and a rinsing liquid with a low surface tension, improving sensitivity and pattern formation efficiency.
Implementation Method 1
Polymers that display increased solubility in a developer after undergoing main chain scission through irradiation with ionizing radiation, such as an electron beam or extreme ultraviolet light (EUV), or short-wavelength light, such as ultraviolet light
Implementation Method 2
rinsing the resist film that has been developed, wherein the rinsing is performed using a rinsing liquid having a surface tension of 20.0 mN/m or less
Implementation Method 3
rinsing the resist film that has been developed, wherein the rinsing is performed using a rinsing liquid having a surface tension of 20.0 mN/m or less
Data Source
AI summary
A method of forming a resist pattern includes: a step of forming a resist film using a positive resist composition containing a solvent and a polymer including monomer units represented by the following formulae (I) and (II), respectively; an exposure step; a development step; and a step of rinsing the developed resist film using a rinsing liquid having a surface tension of 20.0 mN/m or less. In formula (I), R1 is an organic group including 3 to 7 fluorine atoms. In formula (II), R2 is a hydrogen atom, a fluorine atom, or an unsubstituted or fluorine atom-substituted alkyl group, R3 is a hydrogen atom or an unsubstituted or fluorine atom-substituted alkyl group, p and q are each an integer of 0 to 5, and p+q=5.