Streamlined Pellicle Frame for High-Speed Scan Overlay Stability
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Solution Overview
Problem
The challenge of suppressing turbulent flow and vibration of pellicle films during high-speed scanning motion in photolithography processes, which leads to overlay aggravation and pattern deformation, is not adequately addressed by existing pellicle frames, particularly with the transition to higher numerical aperture exposure tools using ArF excimer lasers.
Innovation Solution
Designing a pellicle frame with an outer peripheral surface shaped as a streamline, where the width of this portion is at least 50% of the frame's height, reduces air resistance and mitigates turbulent flow, thereby stabilizing the pellicle film and improving positional accuracy during high-speed scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the thickness of the pellicle film is reduced to increase transmittance of oblique incident light, then the transmittance improves, but the strength of the film is lowered causing vibration during high-speed scanning
Solution Approach 1:
The patent changes the geometric parameters of the pellicle frame, specifically making the outer peripheral portion width at least 50% of the frame height and shaping it with a streamline cross-section. This structural parameter change allows the frame to suppress turbulent flow and reduce air resistance during high-speed scanning, thereby stabilizing the pellicle film without requiring increased film thickness
Solution Approach 2:
The patent applies streamline shaping to the outer peripheral portion of the pellicle frame, creating a curved aerodynamic profile that reduces turbulence. This curvature design allows air to flow smoothly around the frame during high-speed scanning, minimizing vortex formation and stabilizing the pellicle film while maintaining thin film thickness for high transmittance
2Productivity
If high-speed scanning motion is used to increase productivity, then the exposure speed improves, but turbulent flow and vibration increase causing overlay aggravation
Solution Approach 1:
The patent applies preliminary anti-action by designing the pellicle frame with a streamlined outer peripheral portion before the high-speed scanning occurs. This pre-designed aerodynamic shape proactively counteracts the turbulent flow that would normally occur during high-speed scanning, preventing vibration and maintaining positional accuracy without requiring active control systems
Solution Approach 2:
The patent changes the geometric parameters of the pellicle frame, specifically making the outer peripheral portion width at least 50% of the frame height and shaping it with a streamline cross-section. This structural parameter change allows the frame to suppress turbulent flow and reduce air resistance during high-speed scanning, thereby stabilizing the pellicle film and maintaining overlay accuracy at high exposure speeds
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 streamlined pellicle frame effectively suppresses turbulent flow and vibration, enhancing positional accuracy and reducing overlay aggravation, thus supporting the formation of precise patterns in semiconductor and LC display manufacturing.
Implementation Method 1
by tailoring an outer peripheral portion of a pellicle frame to a specific streamline shape, air flow separation is mitigated and air resistance is reduced, and as a result, the turbulent flow upon high-speed scanning motion is suppressed
Data Source
AI summary
The present invention provides a pellicle frame, a pellicle, an exposure original plate with the pellicle, an exposure method, and a semiconductor or liquid-crystal-display manufacturing method, the pellicle frame constituting a pellicle for photolithography.