Synthetic Quartz Glass Substrate Hydrogen Doping
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Solution Overview
Problem
Current methods for preparing synthetic quartz glass substrates for excimer laser applications face challenges such as low productivity, uneven hydrogen molecule concentration leading to microcrack formation, and reduced excimer laser resistance, which affect transmittance and birefringence.
Innovation Solution
A method involving annealing, hydrogen doping, and dehydrogenation treatments of synthetic quartz glass plates to achieve a controlled hydrogen molecule concentration, ensuring high uniformity and resistance to excimer laser irradiation while preventing microcrack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hydrogen doping treatment is performed on a synthetic quartz glass block to introduce hydrogen molecules into the glass, then the hydrogen molecule concentration increases, but the treatment time becomes excessively long (1,500 to 1,800 hours)
Solution Approach 1:
The patent divides the treatment process into two distinct stages: first performing hydrogen doping on the glass block to achieve sufficient hydrogen molecule concentration, then slicing the block into substrates. This segmentation allows the time-consuming doping process to be performed on the block once, rather than repeatedly on each individual substrate, dramatically reducing total treatment time while maintaining adequate hydrogen concentration in the final products
Solution Approach 2:
The patent performs hydrogen doping treatment as a preliminary action before slicing the glass block into substrates. By introducing hydrogen molecules into the block in advance, the subsequent substrate processing requires no additional doping time, effectively pre-preparing the material for future substrate production and significantly improving overall manufacturing efficiency
2Loss of time
If annealing treatment is performed on a synthetic quartz glass block, then the treatment time is reduced, but the hydrogen molecule concentration becomes uneven leading to microcrack formation
Solution Approach 1:
The patent performs hydrogen doping as a preliminary action before annealing and slicing. This ensures that sufficient hydrogen molecules are introduced into the glass structure before any high-temperature treatment that might cause hydrogen loss or redistribution, providing a buffer that maintains uniform hydrogen concentration even after annealing, thereby preventing microcrack formation while allowing optimized annealing cycles
3Reliability
If hydrogen molecule concentration is increased to restore defects and prevent red fluorescence, then excimer laser resistance improves, but uneven concentration distribution causes microcrack formation and reduces transmittance
Solution Approach 1:
The patent segments the hydrogen doping process into a preliminary block-level treatment followed by controlled annealing and substrate slicing. This segmentation allows hydrogen molecules to be introduced uniformly throughout the block structure before any processing that might create concentration gradients, ensuring adequate hydrogen concentration for defect restoration and excimer laser resistance while maintaining uniform distribution to prevent microcracks
Solution Approach 2:
The patent carefully controls the annealing temperature and atmosphere parameters to minimize hydrogen loss and redistribution during the heat treatment process. By optimizing these parameters, the patent achieves the dual goal of removing structural stresses that could cause microcracks while maintaining uniform hydrogen molecule concentration throughout the substrate, thereby improving excimer laser resistance without creating harmful concentration gradients
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 method results in a synthetic quartz glass substrate with reduced birefringence, improved light resistance, suppressed red fluorescence, and enhanced excimer laser resistance, suitable for ArF excimer laser immersion lithography with reduced treatment times.
Implementation Method 1
hydrogen doping treatment of placing the glass in a heating furnace with hydrogen gas atmosphere for introducing hydrogen molecules into the glass
Implementation Method 2
heating the disk in a helium atmosphere for a predetermined time for dehydrogenation treatment
Implementation Method 3
annealing treatment takes about 1,000 hours
Data Source
AI summary
A synthetic quartz glass substrate having a controlled hydrogen molecule concentration is prepared by (a) hot shaping a synthetic quartz glass ingot into a glass block, (b) slicing the glass block into a glass plate, (c) annealing the glass plate at 500-1,250° C. for 15-60 hours, (d) hydrogen doping treatment of the glass plate in a hydrogen gas atmosphere at 300-450° C. for 20-40 hours, and (e) dehydrogenation treatment of the glass plate at 200-400° C. for 5-10 hours.