Bonded-Dopant EUV Underlayer for Faster Photoresist Patterning
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Solution Overview
Problem
EUV photoresists require long exposure times due to low light intensity and substrate heating, leading to less well-defined features and reduced throughput, while loose EUV-absorbing photoelectron-emissive dopants form hydrides, adversely affecting the hydrogen-contributing photosensitive underlayer.
Innovation Solution
Incorporate EUV-absorbing photoelectron-emissive dopants bonded to atoms within a hydrogen-contributing photosensitive underlayer, using a remote plasma to introduce radical species through an ion-shielding and radiation-shielding inlet, reducing the formation of dopant hydrides and enhancing photoelectron generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If EUV photoresist is used with low light intensity, then substrate heating is reduced, but exposure time increases and throughput decreases
Solution Approach 1:
The underlayer is pre-formed with bonded EUV-absorbing photoelectron-emissive dopants before photoresist exposure. These dopants are prepared in advance to emit photoelectrons upon EUV exposure, accelerating the photoresist crosslinking reaction and reducing exposure time without increasing substrate heating
Solution Approach 2:
The underlayer acts as an intermediary between the EUV light source and the photoresist. It contains dopants that absorb EUV photons and emit photoelectrons, which then act as intermediaries to initiate and accelerate the crosslinking reaction in the photoresist, enabling faster processing at lower light intensities
2Power
If loose EUV-absorbing photoelectron-emissive dopants are used, then photoelectron generation is enhanced, but dopant hydride formation occurs and adversely affects the hydrogen-contributing photosensitive underlayer
Solution Approach 1:
The underlayer is formed as a composite material containing carbon-containing polymerizable molecules bonded to EUV-absorbing photoelectron-emissive dopants. This composite structure enables the dopants to emit photoelectrons while the bonded configuration prevents dopant hydride formation, maintaining both photoelectron generation capability and underlayer stability
Solution Approach 2:
The chemical bonding state of the dopants is changed from loose/unbonded to bonded with carbon-containing polymerizable molecules. This parameter change in the dopant configuration prevents hydride formation while maintaining EUV absorption and photoelectron emission capabilities
3Reliability
If long exposure time is used, then photoresist crosslinking is complete, but feature definition deteriorates and throughput decreases
Solution Approach 1:
The underlayer is prepared in advance with bonded dopants that will emit photoelectrons during exposure. This preliminary preparation enables the photoresist crosslinking to proceed rapidly and completely in a short time, achieving both crosslinking completeness and feature definition without the trade-off present in conventional processes
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
This approach reduces exposure times, improves throughput, and ensures well-defined features by maintaining labile hydrogen and photoelectrons for crosslinking reactions in the photoresist layer.
Implementation Method 1
EUV-absorbing photoelectron-emissive dopants bonded to atoms within a hydrogen-contributing photosensitive underlayer
Implementation Method 2
exposing the substrate to a radical species... introducing the radical species from a remote plasma
Data Source
AI summary
Examples are disclosed that relate to use of extreme ultraviolet (EUV)-absorbing photoelectron-emissive dopants that are bonded to atoms in a hydrogen-contributing photosensitive underlayer for a photoresist. One example provides a method of forming a hydrogen-contributing photosensitive underlayer on a substrate. The method comprises exposing the substrate to a dopant precursor and a hydrocarbon precursor, the dopant precursor comprising an extreme ultraviolet (EUV)-absorbing photoelectron-emissive dopant bonded within a carbon-containing polymerizable molecule. The method further comprises exposing the substrate to a radical species formed by a plasma. The method further comprises forming the hydrogen-contributing photosensitive underlayer on the substrate from the dopant precursor and the hydrocarbon precursor by reaction of the dopant precursor and the hydrocarbon precursor with the radical species.