Fluorinated Hydroxystyrene Resin for KrF Lithography
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Solution Overview
Problem
Current pattern formation methods for semiconductor production using KrF excimer laser face challenges in maintaining resolution and rectangularity due to excessive solubility of hydroxystyrene-based resins in organic solvent development, and require anti-reflective films for stepped substrates, increasing production costs.
Innovation Solution
A pattern forming method utilizing a resin composition with a repeating unit capable of acid decomposition and a non-phenolic aromatic group, developed using a KrF excimer laser, which reduces solubility in organic solvents and eliminates the need for anti-reflective films, ensuring high resolution and etching resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If hydroxystyrene-based resin is used for KrF exposure, then sensitivity is improved, but resolution and rectangularity deteriorate due to excessive solubility in organic solvent development
Solution Approach 1:
The patent changes the chemical structure parameters of the resin by introducing a fluorinated group at specific positions (R1 and/or R2) of the hydroxystyrene ring. This structural modification reduces the solubility parameter of the resin in organic solvents while maintaining its sensitivity to KrF exposure, thereby resolving the contradiction between sensitivity and pattern fidelity
Solution Approach 2:
The patent creates a composite resin system by combining fluorinated hydroxystyrene units with other copolymerizable unsaturated compounds. This composite approach allows tuning of solubility characteristics while preserving the desired sensitivity and pattern formation properties
2Ease of manufacture
If conventional resist resin is used for stepped substrates, then coating is possible, but pattern quality deteriorates due to light reflection requiring anti-reflective films
Solution Approach 1:
The fluorinated hydroxystyrene resin acts as an intermediary material that modifies the optical properties of the resist system. The reduced solubility and enhanced etching resistance of this resin eliminate the need for separate anti-reflective film layers, allowing direct coating on stepped substrates while maintaining pattern quality
3Illumination intensity
If aliphatic component resin is used for ArF exposure, then transmittance is improved, but etching resistance deteriorates due to reduced carbon density
Solution Approach 1:
The patent introduces fluorinated aromatic groups into the resin structure, which maintain high light transmittance at KrF wavelength while significantly increasing carbon density. The fluorinated hydroxystyrene units provide both the required optical properties and enhanced etching resistance through their molecular structure
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 achieves high-resolution patterns with excellent etching resistance and rectangularity on stepped substrates without requiring anti-reflective films, enhancing the efficiency and cost-effectiveness of the semiconductor production process.
Implementation Method 1
a resin containing a repeating unit having a group capable of decomposing by the action of an acid to produce a polar group
Implementation Method 2
decomposing an acid generator in the exposed area upon exposure with excimer laser, electron beam, extreme-ultraviolet light or the like to produce an acid
Data Source
AI summary
A pattern forming method comprises (i) a step of forming a film by using an actinic ray-sensitive or radiation-sensitive resin composition containing: (A) a resin containing a repeating unit having a group capable of decomposing by the action of an acid to produce a polar group, (B) a compound capable of generating an acid upon irradiation with an actinic ray or radiation, and (C) a solvent, (ii) a step of exposing the film, and (iii) a step of developing the exposed film by using an organic solvent-containing developer to form a negative pattern, wherein the content of a repeating unit represented by the following formula (I) is less than 20 mol % based on all repeating units in the resin (A) and the resin (A) contains a repeating unit having a non-phenolic aromatic group other than the repeating unit represented by the specific formula.