Triphenylene Topcoat for Deep UV Absorption in EUV Lithography
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Solution Overview
Problem
Conventional topcoat layers used in photolithographic processes with extreme UV light suffer from incomplete absorption of deep UV light, leading to impaired resist pattern quality and gas emissions that degrade exposure apparatuses, limiting the effectiveness of pattern formation in semiconductor manufacturing.
Innovation Solution
A composition for forming a topcoat layer containing a triphenylene derivative with hydrophilic groups is used, which effectively absorbs deep UV light, reducing its transmission to 85% or more and prevents gas emissions, while being easily removable with an alkali developer to maintain pattern integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional topcoat layers are used in extreme UV photolithography, then the process can proceed with standard materials, but deep UV light transmission causes resist pattern impairment and gas emissions
Solution Approach 1:
The patent modifies the chemical composition parameters of the topcoat layer by incorporating specific polymers with high deep UV absorption coefficients and controlled extreme UV transmission. This changes the optical properties of the topcoat to selectively block harmful deep UV light while maintaining necessary extreme UV light transmission for the lithography process.
Solution Approach 2:
The patent creates a composite topcoat material system combining multiple polymer components with complementary properties: one polymer provides deep UV absorption while another ensures extreme UV transmission. This composite approach allows simultaneous optimization of multiple optical properties that cannot be achieved with single materials.
2Device complexity
If conventional topcoat layers are used, then material selection is simple, but gas emissions from the resist layer stain optical elements and degrade exposure accuracy
Solution Approach 1:
The topcoat layer acts as an intermediary barrier between the resist layer and the exposure apparatus optical elements. It prevents volatile substances and gases generated during extreme UV exposure from reaching and staining the optical elements, while still allowing the necessary light transmission for the lithography process.
Solution Approach 2:
The patent converts the potential harm of using conventional topcoat materials into a benefit by carefully selecting polymers that, while providing the necessary extreme UV transmission, also happen to have high deep UV absorption. This turns what could be a limitation into a protective feature that blocks harmful deep UV light.
3Manufacturing precision
If a topcoat layer is added to block deep UV light, then pattern quality improves, but the process complexity and material selection difficulty increase
Solution Approach 1:
The patent applies local quality by designing the topcoat layer with specific functional zones: the polymer composition is optimized to provide deep UV absorption at the interface with the resist layer, while maintaining extreme UV transmission throughout the topcoat thickness. This localized optimization of material properties achieves pattern quality improvement without excessive complexity.
4Manufacturing precision
If extreme UV light sources are used for high-resolution patterning, then pattern resolution improves, but deep UV light emission impairs resist pattern quality
Solution Approach 1:
The patent converts the harmful deep UV light emission from extreme UV sources into a beneficial filtering opportunity. By incorporating deep UV-absorbing polymers in the topcoat layer, the system uses the presence of deep UV light as a signal to apply selective absorption, blocking these harmful wavelengths while allowing the desired extreme UV light to pass through for high-resolution patterning.
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 triphenylene derivative-based topcoat layer significantly improves deep UV light absorption, protects resist patterns from roughness and shape impairment, and prevents gas-induced staining, enabling accurate and residue-free pattern formation in extreme UV photolithography.
Implementation Method 1
A composition for forming a topcoat layer containing a triphenylene derivative... which effectively absorbs deep UV light, reducing its transmission to 85% or more
Implementation Method 2
prevents gas emissions that degrade exposure apparatuses
Implementation Method 3
being easily removable with an alkali developer to maintain pattern integrity
Data Source
AI summary
To provide a composition for forming a topcoat layer enabling to produce a pattern excellent in roughness and in pattern shape, and also to provide a pattern formation method employing that.A composition for forming a topcoat layer, containing a solvent and a triphenylene derivative having a hydrophilic group; and also a method of forming a pattern by casting the above composition on a resist surface and then by subjecting it to exposure and development. The composition may further contain a polymer.