Streamlined Pellicle Frame to Suppress Turbulence During Scanning
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Solution Overview
Problem
The challenge in photolithography is the occurrence of turbulent flow and vibration of pellicle films during high-speed scanning motion, leading to overlay aggravation and pattern deformation due to the use of thinner pellicle films to maintain transmittance for oblique incident light, which compromises film strength and positional accuracy.
Innovation Solution
A pellicle frame with a streamlined outer shape is designed to mitigate turbulent flow and reduce air resistance, thereby suppressing film vibration and overlay aggravation, using a streamlined shape with a specific width ratio for the outer peripheral portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the thickness of the pellicle film is reduced to increase transmittance for oblique incident light, then the transmittance is improved, but the strength of the film is lowered causing vibration during high-speed scanning motion
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 vibration during high-speed scanning, enabling the use of thinner pellicle films for improved transmittance without sacrificing film strength.
2Manufacturing precision
If the numerical aperture of the exposure tool is increased to enhance resolution, then the resolution is improved, but the angle of oblique incidence increases causing transmittance to lower
Solution Approach 1:
The patent addresses this contradiction by optimizing the pellicle frame geometry - specifically setting the outer peripheral portion width to at least 50% of the frame height and using a streamline cross-sectional shape. This structural optimization reduces vibration during high-speed scanning, allowing thinner pellicle films to be used that maintain high transmittance even for oblique incident light at higher numerical apertures.
3Stability of the object's composition
If the width of the pellicle frame is increased to suppress turbulent flow, then the vibration suppression is improved, but the exposure area is reduced
Solution Approach 1:
The patent applies local quality by specifically designing the outer peripheral portion of the pellicle frame with a width of at least 50% of the frame height and a streamline cross-sectional shape. This localized structural enhancement at the outer peripheral portion effectively suppresses turbulent flow and vibration, while the central exposure area remains maximized 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 streamlined pellicle frame effectively reduces turbulent flow and vibration, enhancing positional accuracy and reducing overlay issues, particularly in high-speed scanning motions, thus improving pattern formation in semiconductor and LC display manufacturing.
Implementation Method 1
a pellicle frame to construct a photolithography pellicle, having an outer peripheral surface which is streamline shaped
Implementation Method 2
suppress turbulent flow which is likely to occur upon high-speed scanning motion
Implementation Method 3
air flow separation is mitigated and air resistance is reduced
Implementation Method 4
The pellicle film is composed of a material having a high transmittance to exposure radiation
Implementation Method 5
the light transmitted by the pellicle has an increased angle of oblique incidence in a peripheral portion
Implementation Method 6
The transmittance of the pellicle is generally set such that a maximum transmittance is available with respect to perpendicular incident light
Implementation Method 7
a gas-tight gasket formed on the lower end surface of the pellicle frame. The pellicle film is composed of a material having a high transmittance to exposure radiation. A pressure-sensitive adhesive (PSA) is used as the gas-tight gasket
Data Source
Figure 1~2
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, wherein the outer peripheral lateral face of the pellicle frame is formed in a streamlined shape, and the width of the outer peripheral portion formed in the streamlined shape is 50% or more of the height of the pellicle frame. According to the present invention, rendering the outer-peripheral lateral face part of the pellicle frame in a special streamlined shape lessens detachment of air, enabling air resistance to be reduced, and as a result thereof, turbulence during high-speed scanning movement is kept under control and post-exposure deterioration of the overlay can be kept under control.