Fluorinated Polymer Resist Composition for 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 polymers like α-methylstyrene-methyl α-chloroacrylate copolymers fail to sufficiently inhibit this collapse while maintaining sensitivity and clarity.
Innovation Solution
A polymer comprising a monomer unit with an organic group containing 5 to 7 fluorine atoms and another monomer unit, used in a positive resist composition, which inhibits resist pattern collapse and improves sensitivity by forming a clear resist pattern when exposed to ionizing radiation and developed with a solvent of low surface tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional positive resist polymer (α-methylstyrene-methyl α-chloroacrylate copolymer) is used, then sensitivity is improved, but resist pattern collapse occurs during formation
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer by introducing fluorine-containing monomer units (with 5-7 fluorine atoms in the organic group) into the polymer structure. This parameter change in the polymer's chemical composition modifies its solubility characteristics and resistance to developer, thereby preventing resist pattern collapse while maintaining sensitivity.
Solution Approach 2:
The patent creates a composite polymer structure by combining fluorine-containing monomer units (providing collapse resistance) with conventional monomer units (maintaining sensitivity). This composite approach integrates the beneficial properties of both material types into a single resist polymer that avoids the drawbacks of conventional polymers.
2Manufacturing precision
If solubility in developer is increased for exposed sections, then pattern clarity is improved, but dissolution of non-exposed sections increases causing collapse
Solution Approach 1:
The patent modifies the solubility parameter of the resist polymer by incorporating fluorine-containing monomer units. This changes the polymer's interaction with the developer, creating a situation where exposed sections (which have undergone main chain scission) become sufficiently soluble for clear pattern formation, while non-exposed sections maintain adequate integrity to prevent collapse.
Solution Approach 2:
The patent creates local quality differences in the resist film by having exposed sections undergo chemical changes (main chain scission) that increase their solubility, while non-exposed sections retain their original low-solubility characteristics. This local differentiation enables clear pattern formation without compromising overall film stability.
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 effectively prevents resist pattern collapse and enhances sensitivity, allowing for the efficient formation of clear resist patterns, even when exposed to ionizing radiation, by incorporating specific fluorine-containing monomer units and using a developer with a surface tension of 17 mN/m or less.
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
The formation of a resist pattern using a resist film formed using a positive resist comprises an α-methylstyrene-methyl α-chloroacrylate copolymer 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
Data Source
AI summary
Provided is a polymer that when used as a main chain scission-type positive resist, can sufficiently inhibit resist pattern collapse, can favorably form a clear resist pattern, and can also improve sensitivity. The polymer includes a monomer unit (A) represented by general formula (I), shown below, and a monomer unit (B) represented by general formula (II), shown below. [In formula (I), R1 is an organic group including not fewer than 5 and not more than 7 fluorine atoms. In formula (II), R2 is a hydrogen atom, a fluorine atom, an unsubstituted alkyl group, or a fluorine atom-substituted alkyl group, R3 is a hydrogen atom, an unsubstituted alkyl group, or a fluorine atom-substituted alkyl group, p and q are each an integer of not less than 0 and not more than 5, and p+q=5.]