Fluorine-Containing Resist Polymer Pattern Collapse Prevention
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Solution Overview
Problem
Resist pattern collapse occurs during the formation of resist patterns using conventional positive resists, and existing methods fail to sufficiently inhibit this collapse while maintaining clear pattern formation.
Innovation Solution
A method involving a positive resist composition with specific fluorine-containing polymers and a developer having a surface tension of 17 mN/m or less is used to form a resist pattern, inhibiting collapse and enhancing clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional positive resist comprising an α-methylstyrene-methyl α-chloroacrylate copolymer is used, then high sensitivity is achieved, but resist pattern collapse occurs during formation
Solution Approach 1:
The patent modifies the chemical composition parameters of the resist polymer by incorporating fluorine-containing monomer units (specifically fluorinated α-chloroacrylate units) into the copolymer structure. This chemical parameter change alters the polymer's interaction with the developer solution, preventing pattern collapse while maintaining the high sensitivity characteristic of conventional positive resists.
Solution Approach 2:
The patent creates a composite polymer structure by combining α-methylstyrene units with fluorinated α-chloroacrylate units in a copolymer. This composite material approach integrates the high sensitivity of α-methylstyrene-based resists with the collapse-resistant properties introduced by the fluorinated units, achieving both objectives simultaneously.
2Manufacturing precision
If the solubility in developer of the exposed section is increased, then a clear resist pattern is formed, but resist pattern collapse occurs
Solution Approach 1:
The patent changes the chemical parameters of the resist polymer by introducing fluorinated monomer units, which modify the solubility characteristics of the exposed sections. This parameter change enables sufficient solubility difference between exposed and unexposed areas for clear pattern formation, while the fluorinated structure simultaneously provides collapse resistance.
3Manufacturing precision
If a developer with high solubility for the exposed section is used, then pattern clarity is improved, but pattern collapse increases
Solution Approach 1:
Rather than changing the developer properties, the patent changes the resist polymer parameters by incorporating fluorinated units. This approach allows the use of conventional developers with high solubility for exposed sections to achieve clear patterns, while the fluorinated polymer structure inherently prevents collapse, decoupling these two requirements.
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 method effectively prevents resist pattern collapse and improves the clarity of the resist pattern, allowing for better formation and increased sensitivity in semiconductor production processes.
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 short-wavelength light, such as ultraviolet light
Implementation Method 2
irradiation with ionizing radiation or the like
Implementation Method 3
utilizes the difference in rates of dissolution in developer of an exposed section that is irradiated with ionizing radiation or the like and a non-exposed section that is not irradiated
Implementation Method 4
by using a developer having a surface tension that is not more than a specific value in development of a resist formed using a positive resist composition that contains a specific polymer including at least one fluorine atom, a clear resist pattern can be favorably formed while also sufficiently inhibiting resist pattern collapse
Data Source
AI summary
The objective is to favorably form a clear resist pattern using a resist composition containing a polymer that can inhibit resist pattern collapse when used as a main chain scission-type positive resist. A method of forming a resist pattern includes: a step of forming a resist film using a positive resist composition containing a polymer including a monomer unit (A) represented by general formula (I), shown below, and a monomer unit (B) represented by general formula (II), shown below, with a proviso that at least one of the monomer unit (A) and the monomer unit (B) includes at least one fluorine atom; an exposure step; and a development step. The development is carried out using a developer having a surface tension of 17 mN/m or less.