Chemically-Amplified Resist Polymer for Lithography Edge Roughness
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Solution Overview
Problem
Current positive-tone resist materials used in semiconductor lithography face a trade-off between sensitivity, resolution, and nano edge roughness, particularly when forming fine patterns with line widths of 0.25 μm or less, where high sensitivity and high resolution are desired while minimizing nano edge roughness.
Innovation Solution
A polymer with a specific repeating unit structure, combined with a photoacid generator, is used to create a radiation-sensitive composition that is insoluble in alkali but becomes soluble upon acid exposure, effectively addressing the trade-off by achieving high sensitivity, high resolution, and low nano edge roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sensitivity of a positive-tone resist is increased, then the wafer processing time is reduced, but the resolution and nano edge roughness deteriorate
Solution Approach 1:
The patent modifies the chemical structure of the polymer by introducing specific repeating units with heteroatoms (O, S, CO, COO, SO, SO2) in the cyclic structure portion. This structural parameter change enables the polymer to achieve both high sensitivity and high resolution simultaneously by controlling the acid-catalyzed reaction characteristics and reducing unwanted side reactions that cause edge roughness
Solution Approach 2:
The patent uses a composite approach by combining the specially designed polymer with a photoacid generator to create a chemically-amplified resist system. This composite material achieves enhanced sensitivity through chemical amplification while the specific polymer structure maintains resolution and minimizes nano edge roughness
2Productivity
If a chemically-amplified resist composition is used to increase sensitivity, then the sensitivity improves, but the nano edge roughness increases
Solution Approach 1:
The patent changes the chemical parameters of the polymer by incorporating repeating units with specific cyclic structures containing heteroatoms. This modification optimizes the acid-catalyzed deprotection reaction to proceed uniformly, achieving high sensitivity through chemical amplification while preventing the irregular etching that causes nano edge roughness
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 solution enables the formation of a chemically-amplified positive-tone resist film that accurately and stably produces fine patterns with reduced nano edge roughness, suitable for deep ultraviolet rays, X-rays, and electron beams, while maintaining excellent sensitivity and resolution.
Implementation Method 1
a chemically-amplified resist composition that mainly includes a phenolic polymer (phenolic acid-labile polymer) that is insoluble or scarcely soluble in an alkaline solution, but becomes soluble in an alkaline solution due to an acid
Implementation Method 2
a compound (sulfonic acid generator) that generates sulfonic acid upon irradiation of active rays or radiation
Data Source
AI summary
A polymer includes a repeating unit shown by a general formula (1). R1 represents a hydrogen atom, a methyl group, a fluorine atom, or a trifluoromethyl group. R2 represents a substituted or unsubstituted aryl group having 6 to 22 carbon atoms. Y represents a carbon atom. X represents —X1Z1X2— which is an atomic group which forms a cyclic structure including a heteroatom together with Y. Z1 represents —O—, —S—, —CO—, —COO—, —SO—, or —SO2—. Each of X1 and X2 individually represents a single bond, a methylene group, or an alkylene group having 2 to 25 carbon atoms. Each of X1 and X2 is unsubstituted or substituted with a substituent, and optionally a carbon atom included in X1 and a carbon atom included in X2 are bonded via a divalent group.