Hypervalent Iodine Resist Composition for High-Resolution EUV Patterning
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Solution Overview
Problem
Existing resist compositions face challenges in achieving high sensitivity and resolution in photolithography, particularly in electron beam (EB) and extreme ultraviolet (EUV) lithography, due to issues such as acid diffusion, shot noise, and the limitations of chemically amplified materials, which result in pattern collapse and disconnection.
Innovation Solution
A resist composition containing a polymer with a hypervalent iodine structure and a carboxy group-containing compound, which forms a resist film that exhibits excellent resolving power and is suitable for precise micropatterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemically amplified resist composition is used to enhance sensitivity and contrast, then sensitivity and contrast are improved, but acid diffusion causes image blur and resolution deteriorates
Solution Approach 1:
The patent removes the chemically amplified mechanism (acid generator and polymer with acid labile group) from the resist composition, extracting the source of acid diffusion that causes image blur. This extraction eliminates the fundamental contradiction by using a non-chemically amplified resist material that relies solely on direct photon absorption and thermal effects, thereby achieving both high sensitivity and high resolution without acid diffusion-related blurring.
Solution Approach 2:
The patent changes the fundamental mechanism parameter from chemical amplification to direct thermal and photochemical effects. By using a resist composition without acid generators and relying on thermal energy and direct photon absorption, the system achieves sharp patterns at small feature sizes while maintaining high sensitivity through optimized thermal and photochemical properties.
2Manufacturing precision
If post-exposure bake temperature and time are reduced to minimize acid diffusion, then image blur is reduced, but sensitivity and contrast are drastically reduced
Solution Approach 1:
The patent eliminates the chemically amplified mechanism that requires post-exposure bake for acid generation and diffusion. By removing the acid generator and polymer with acid labile group, the system no longer depends on PEB conditions, thereby achieving sharp patterns without the trade-off between minimizing image blur and maintaining sensitivity through reduced PEB parameters.
Solution Approach 2:
The patent replaces the chemical amplification mechanism with direct thermal and photochemical effects. Instead of relying on acid diffusion facilitated by thermal energy in PEB, the system uses direct thermal effects and photon absorption to achieve the desired pattern, eliminating the need to balance PEB parameters for both sensitivity and resolution.
3Manufacturing precision
If EUV exposure is used to achieve smaller pattern features, then resolution is improved, but shot noise increases and sensitivity deteriorates
Solution Approach 1:
The patent optimizes the resist composition parameters for EUV exposure by incorporating high-EUV-absorption elements (iodine, bromine, or chlorine) and adjusting the molecular weight and composition ratios. This parameter optimization enables the system to achieve high sensitivity despite the inherent shot noise in EUV exposure, while maintaining the ability to form small pattern features.
Solution Approach 2:
The patent uses a composite resist composition combining specific polymers with high-EUV-absorption elements (iodine, bromine, or chlorine) and carboxy group-containing compounds. This composite material structure enhances EUV absorption and thermal effects, thereby improving sensitivity and enabling reliable pattern formation at small feature sizes despite shot noise limitations.
4Manufacturing precision
If line-and-space pattern size is reduced to increase integration density, then manufacturing precision is improved, but pattern collapse and disconnection increase
Solution Approach 1:
The patent removes the chemically amplified mechanism that causes acid diffusion and subsequent pattern collapse at small feature sizes. By using a non-chemically amplified resist composition, the system eliminates the fundamental cause of pattern instability, thereby achieving stable pattern formation even at reduced line-and-space dimensions.
Solution Approach 2:
The patent changes the resist mechanism from chemical amplification to direct thermal and photochemical effects, which do not suffer from acid diffusion limitations. This parameter change enables stable pattern formation at small feature sizes by eliminating the chemical mechanisms that lead to pattern collapse and disconnection.
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 provides high sensitivity and resolution in photolithography using i-line, KrF excimer laser light, ArF excimer laser light, EB, or EUV, effectively reducing pattern blur and improving micropatterning capabilities.
Implementation Method 1
incorporate an element having high EUV absorption... highly EUV-absorbing iodine atoms
Implementation Method 2
a laminate comprising a substrate and a resist film obtained from the resist composition... by ligand exchange between the hypervalent iodine compound and the carboxy group-containing compound
Data Source
AI summary
The resist composition contains a polymer containing a repeat unit having a hypervalent iodine structure having the formula (1), a carboxy group-containing compound, and a solvent. The non-chemically amplified resist composition is excellent in sensitivity and maximum resolution in photolithography using high-energy radiation, such as electron beam (EB) lithography and EUV lithography.