Positive Resist Composition with Polycyclic Aromatic Skeleton
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Solution Overview
Problem
Current resist compositions face challenges in achieving high sensitivity, high resolution, excellent pattern profile, and small line edge roughness (LER) while maintaining good dry etching resistance, particularly when forming fine patterns using electron beams or extreme ultraviolet rays, especially on substrates with light-shielding films containing heavy atoms.
Innovation Solution
A positive resist composition incorporating a polymer compound with a specific acid-decomposable acetal structure, where a hydrogen atom of a phenolic hydroxyl group is replaced by an acid labile group, enhancing dry etching resistance and sensitivity through efficient acid generation and secondary electron acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the film thickness is reduced to form ultrafine patterns, then the pattern collapse problem is prevented, but the dry etching resistance deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the resist film by introducing a polycyclic aromatic skeleton structure (naphthalene or anthracene) with specific molecular weight and structural characteristics. This structural modification enables the film to maintain adequate dry etching resistance even at reduced thicknesses of 50 nm or less, while still achieving ultrafine pattern formation capability.
Solution Approach 2:
The patent employs a composite resin system combining polycyclic aromatic compounds (naphthalene or anthracene derivatives) with specific functional groups. This composite structure integrates both the thin-film formation capability and enhanced dry etching resistance in a single resist material, resolving the contradiction between film thickness reduction and etching resistance maintenance.
2Manufacturing precision
If the accelerating voltage of the electron beam is increased to reduce forward scattering, then the pattern resolution improves, but the electron energy trapping ratio decreases and back scattering increases
Solution Approach 1:
The patent converts the harmful back-scattering effect into a beneficial outcome by using the polycyclic aromatic skeleton structure to trap back-scattered electrons. The unique electronic structure of naphthalene or anthracene derivatives captures these electrons, preventing them from causing resolution degradation, thereby transforming a harmful phenomenon into a neutral or beneficial effect.
Solution Approach 2:
The patent modifies the electronic and structural parameters of the resist material by incorporating polycyclic aromatic skeletons, which alter the electron interaction characteristics. This changes the energy trapping mechanism to be more effective at higher accelerating voltages, maintaining resolution while mitigating back-scattering damage.
3Object-affected harmful factors
If a light-shielding film containing heavy atoms is used in photomask blanks, then the light shielding performance improves, but the back scattering effect increases significantly
Solution Approach 1:
The patent applies the same principle of converting harm into benefit for photomask applications. The polycyclic aromatic skeleton structure in the resist coating on photomask blanks captures back-scattered electrons from the heavy atom light-shielding layer, transforming the harmful back-scattering effect into a controlled phenomenon that does not degrade isolated pattern resolution.
4Manufacturing precision
If conventional resins are used for thin film formation, then the sensitivity decreases, but the pattern profile and line edge roughness deteriorate
Solution Approach 1:
The patent fundamentally changes the chemical and structural parameters of the resist material by using polycyclic aromatic skeletons with specific molecular weights and functional group configurations. This structural transformation simultaneously improves sensitivity, pattern profile, and line edge roughness characteristics, breaking the conventional trade-off between these parameters.
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 composition achieves high sensitivity, high resolution, excellent pattern profile, and small line edge roughness (LER) along with good dry etching resistance, effectively addressing the limitations of existing technologies in microfabrication and nanoimprint mold structures.
Implementation Method 1
a compound (B) capable of generating an acid upon irradiation with actinic rays or radiation
Implementation Method 2
exposure using an electron beam or an extreme ultraviolet ray
Implementation Method 3
the effect of electron scattering (forward scattering) in the resist film
Data Source
AI summary
A positive resist composition contains: (A) a polymer compound having a structure where a hydrogen atom of a phenolic hydroxyl group is replaced by an acid labile group represented by the following formula (I): wherein R represents a monovalent organic group; A represents a group having a polycyclic hydrocarbon ring structure or a group having a polycyclic heterocyclic structure; and * represents a bonding position to an oxygen atom of the phenolic hydroxyl group.