Pellicle Ventilation Hole Segmentation for Rigidity
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Solution Overview
Problem
Existing pellicles for semiconductor and liquid crystal display manufacturing face challenges in maintaining high ventilation characteristics while preventing dust generation, leading to rigidity issues and increased risk of filter member breakage and misalignment during handling.
Innovation Solution
A pellicle design featuring a through hole with an outer stepped portion for accommodating the filter member, an inner stepped portion to enhance ventilation, and a ventilation hole configuration that reduces protrusion and improves attachment accuracy, combined with a pressure-sensitive adhesive layer for enhanced dust prevention and ventilation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of ventilation holes are provided to ensure ventilation amount, then ventilation performance is improved, but rigidity of the pellicle frame deteriorates
Solution Approach 1:
The ventilation hole is segmented into multiple functional zones: an outer stepped portion for filter accommodation, an inner stepped portion for ventilation enhancement, and a through hole for pressure equalization. This segmentation allows the single hole to perform multiple functions that previously required multiple holes, thereby maintaining ventilation performance while preserving frame rigidity.
Solution Approach 2:
The filter member is nested within the outer stepped portion of the ventilation hole, creating a compact structure where the filter is housed inside the frame rather than protruding outward. This nesting eliminates the need for multiple external filters while maintaining effective filtration and ventilation.
2Reliability
If filter member protrudes from pellicle frame to ensure filter function, then filtration is effective, but risk of breakage and misalignment increases
Solution Approach 1:
The filter member is nested within the outer stepped portion of the ventilation hole, creating a compact structure where the filter is housed inside the frame rather than protruding outward. This nesting eliminates the need for multiple external filters while maintaining effective filtration and ventilation.
Solution Approach 2:
The outer stepped portion is pre-formed as part of the ventilation hole structure, providing a ready-made accommodation space for the filter member. This preliminary structural preparation ensures proper filter positioning and reduces handling complexity during assembly.
3Reliability
If multiple filter members are installed to ensure ventilation amount, then ventilation performance is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The ventilation hole is segmented into multiple functional zones: an outer stepped portion for filter accommodation, an inner stepped portion for ventilation enhancement, and a through hole for pressure equalization. This segmentation allows the single hole to perform multiple functions that previously required multiple holes, thereby maintaining ventilation performance while preserving frame rigidity.
Solution Approach 2:
The ventilation hole structure serves multiple functions simultaneously: the outer stepped portion accommodates the filter, the inner stepped portion enhances ventilation, and the through hole equalizes pressure. This multi-functionality eliminates the need for separate components that would otherwise be required.
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 design achieves improved ventilation characteristics, reduced risk of filter member breakage and misalignment, and easier handling, resulting in a pellicle with high reliability and workability, even with a reduced number of ventilation holes, thus maintaining high dust prevention and exposure accuracy.
Implementation Method 1
a pressure-sensitive adhesive layer made of polybutene resin, polyvinyl acetate resin, acrylic resin and the like to be attached to the photomask
Implementation Method 2
a sheet-shaped one in which a porous thin film obtained by stretching and working polytetrafluoroethylene (PTFE) or the like is used as a filter film
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
There is provided a pellicle (14) having a rectangular pellicle frame (11) formed of four side bars, having a through hole (12) made through at least one of the frame bars for adjusting a pressure of a space formed within the pellicle frame equal to a pressure outside the pellicle frame; and a filter member (18) disposed to cover up an external opening of the through hole for preventing entrance of particles into the space, wherein the through hole is formed with: (1) an outer stepped portion (16) defining a first recess, opening outside the pellicle frame, for accommodating the filter member, (2) an inner stepped portion (17) defining a second recess, opening in a bottom of the first recess, and (3) a ventilation hole (12) with one end opening in a bottom of the second recess of the inner stepped portion and the other end opening in the space within the pellicle frame.