Non-Chemically Amplified Resist Composition for EUV Resolution
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Solution Overview
Problem
Existing resist compositions face challenges in achieving high sensitivity and resolution for micropatterning, particularly in EUV lithography, due to acid diffusion, shot noise, and limitations of chemically amplified and metal resist compositions.
Innovation Solution
A resist composition comprising a hypervalent iodine compound, an onium salt, and a carboxy-containing compound, which forms a resist film with high sensitivity and resolution, suitable for photolithography using high-energy radiation like EB and EUV lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemically amplified resist composition is used to enhance sensitivity and contrast through acid diffusion, then sensitivity and contrast are improved, but acid diffusion causes image blur and reduces resolution for fine patterns
Solution Approach 1:
The patent extracts and removes the acid diffusion mechanism from the chemically amplified resist system by using a non-chemically-amplified resist composition based on PMMA. This eliminates the harmful acid diffusion effect while maintaining the essential photoresist functionality through direct photochemical decomposition without chemical amplification.
Solution Approach 2:
The patent changes the fundamental chemical mechanism parameter from chemically amplified (acid-catalyzed) to non-chemically-amplified (direct photochemical). This parameter change transitions the resist system from one relying on acid diffusion for sensitivity enhancement to one using direct photodecomposition, thereby eliminating image blur while maintaining patterning capability.
2Manufacturing precision
If non-chemically-amplified resist material like PMMA is used to avoid acid diffusion, then resolution is improved, but sensitivity is insufficient
Solution Approach 1:
The patent employs a composite resist composition containing PMMA as the base polymer combined with specific additives including sulfonic acid compounds and metal compounds. This composite structure maintains the resolution advantages of PMMA while the additives enhance sensitivity through alternative photochemical mechanisms that do not rely on acid diffusion.
3Manufacturing precision
If negative resist materials like HSQ are used to achieve high resolution through crosslinking, then edge roughness is reduced and resolution is improved, but sensitivity is insufficient and additional process steps are required
Solution Approach 1:
The patent inverts the conventional negative resist approach by using a positive resist system (PMMA-based) that achieves high resolution without requiring crosslinking. Instead of making the exposed regions insoluble through crosslinking (negative tone), the patent uses direct photodecomposition to make exposed regions soluble, eliminating the need for additional reversal steps while maintaining high resolution.
4Manufacturing precision
If EUV lithography is used to achieve smaller pattern features, then maximum resolution is improved, but shot noise increases and affects pattern fidelity
Solution Approach 1:
The patent converts the limitation of low photon flux in EUV lithography into a benefit by using a resist composition with extremely high quantum efficiency. The PMMA-based system with optimized additives responds so efficiently to individual EUV photons that the stochastic nature of photon arrival (shot noise) is minimized, allowing high-resolution patterning despite the low photon flux inherent in EUV exposure.
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 and resolution, reducing acid diffusion and shot noise effects, enabling precise micropatterning with improved pattern fidelity.
Implementation Method 1
Addition of an acid generator capable of generating a bulky acid is effective for suppressing acid diffusion
Implementation Method 2
incorporate an element having high EUV absorption
Implementation Method 3
Hydrogensilsesquioxane (HSQ) is a negative resist material which turns insoluble in alkaline developer through crosslinking by condensation reaction of silanol generated upon EUV exposure
Implementation Method 4
It is a positive resist material which increases solubility in organic solvent developer through the mechanism that the molecular weight becomes lower as a result of scission of the main chain upon EUV exposure
Data Source
AI summary
A resist composition comprising a hypervalent iodine compound, an onium salt, a carboxy-containing compound, and a solvent is provided. When processed by photolithography using high-energy radiation, the resist composition exhibits a high sensitivity and resolution. The non-chemically-amplified resist composition exhibits a high sensitivity and maximum resolution when processed by photolithography using high-energy radiation, typically EB and EUV lithography, and a patterning process using the same.