Metal-Complex Resist Composition for EUV Sensitivity and Low LWR
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Solution Overview
Problem
Existing resist compositions face challenges in achieving high sensitivity, resolution, and low line width roughness (LWR) in high-energy ray lithography, particularly in EUV lithography, due to acid diffusion and shot noise, while maintaining stability and handling ease.
Innovation Solution
A resist composition containing a metal complex with a ligand having three or more coordinating functional groups, preferably zinc, is used to form a stable resist film that is sensitive and resistant to acid diffusion, combined with an organic solvent and optional photoacid generator and radical scavenger, to enhance sensitivity and LWR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acid diffusion is suppressed by lowering PEB temperature or shortening PEB time, then resolution is improved, but sensitivity and contrast are remarkably lowered
Solution Approach 1:
The invention changes the fundamental parameter of acid generation by using bulky acid generators that produce large acid molecules. This physical change in acid size prevents acid diffusion regardless of PEB conditions, allowing the system to achieve high resolution without sacrificing sensitivity. The bulky acid molecules simply cannot diffuse through the resist matrix effectively, decoupling the resolution from PEB parameter optimization.
Solution Approach 2:
The invention uses composite material design by copolymerizing onium salt acid generators with polymerizable olefins into a polymer matrix. This creates a chemically amplified resist composition where the acid generator is integrated into the polymer structure, enabling controlled acid release and diffusion characteristics that simultaneously achieve high sensitivity and high resolution.
2Productivity
If PMMA is used as positive resist material, then sensitivity is improved, but etching resistance is low and outgas is large
Solution Approach 1:
The invention creates a composite resist material by copolymerizing onium salt acid generators with polymerizable olefins. This composite structure combines the sensitivity benefits of chemically amplified resists with the etching resistance of crosslinkable polymer networks, achieving both high sensitivity and high etching resistance simultaneously.
Solution Approach 2:
The invention applies local quality changes by introducing crosslinkable functional groups at specific locations within the polymer chain. These localized crosslinking sites provide etching resistance where needed while maintaining the overall polymer structure's sensitivity to acid generation and dissolution contrast.
3Manufacturing precision
If HSQ or chlorine-substituted calixarenes are used as negative resist materials, then resolution is improved, but sensitivity is insufficient
Solution Approach 1:
The invention changes the chemical parameters of the resist material by incorporating onium salt acid generators that produce bulky acid molecules upon exposure. This chemical modification enables the resist to achieve both high sensitivity to exposure and high resolution by controlling acid diffusion through the polymer matrix structure.
Solution Approach 2:
The invention creates a composite material system combining polymerizable olefins with onium salt acid generators. This composite approach integrates the advantages of both components: the polymer provides sensitivity and processability, while the acid generator provides resolution control through bulky acid formation and limited diffusion.
4Productivity
If inorganic resist composition with high EUV light absorption element is used, then sensitivity is improved, but storage stability and solubility are insufficient
Solution Approach 1:
The invention creates an organic-inorganic composite resist material by incorporating metal complexes into an organic polymer matrix. This composite structure combines the high EUV absorption and sensitivity of inorganic metal complexes with the storage stability, solubility, and processability of organic polymers, achieving all desired properties simultaneously.
Solution Approach 2:
The organic polymer matrix acts as an intermediary that hosts the inorganic metal complex. This intermediary provides the necessary solubility in organic solvents and storage stability, while the metal complex provides high EUV absorption. The polymer mediates between the inorganic sensitivity-enhancing component and the practical requirements of storage and processing.
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, excellent resolution, and low LWR, with improved stability and reduced performance degradation over time, making it suitable for precise fine processing in EUV and EB lithography.
Implementation Method 1
A phenomenon has been observed in which not only critical dimension uniformity (CDU) and line width roughness (LWR) increase due to the effect of shot noise, but also a hole is blocked with a probability of one in several millions. When the hole is blocked, a current failure occurs and a transistor does not operate, which adversely affects the performance of an entire device.
Implementation Method 2
a metal complex composed of a metal atom and a ligand having three or more coordinating functional groups
Implementation Method 3
PMMA is a positive resist material in which the main chain is cut by an electron beam (EB) or EUV irradiation, and the solubility in an organic solvent developer is improved as the molecular weight is reduced
Data Source
AI summary
The resist composition is excellent in sensitivity, resolution, and LWR and is stable and easy to handle in photolithography using a high-energy ray, and a pattern forming method using the resist composition. The resist composition contains a metal complex composed of a metal atom and a ligand having three or more coordinating functional groups.