Pellicle Air Passage Ventilation Design
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Solution Overview
Problem
The reduction in pellicle height limits the size of air passage openings and filter effective areas, making it difficult to mitigate pressure differences across the pellicle membrane, especially in EUV exposure environments, which can lead to pellicle membrane breakage.
Innovation Solution
The pellicle design features air passages with openings that can be oriented upward or downward, allowing for a larger effective filtering area without height restrictions, and a filter that can cover these openings to ensure sufficient ventilation and prevent pressure-induced damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the pellicle height is reduced, then the overall size is minimized, but the air passage opening area and filter effective area are limited, making it difficult to mitigate pressure differences
Solution Approach 1:
The air passage opening is oriented in the upward direction (vertical dimension) rather than only in the horizontal direction, allowing the opening area to be independent of the pellicle height. This dimensional change enables sufficient ventilation area even when the pellicle height is minimized.
Solution Approach 2:
The air passage is segmented into multiple components: the passage itself, the opening oriented upward, and the filter covering the opening. This segmentation allows each component to be optimized independently, with the opening area not constrained by the overall pellicle height.
2Reliability
If the filter effective area is increased to cover larger air passage openings, then pressure equalization improves, but the pellicle height must be increased
Solution Approach 1:
By orienting the air passage opening upward in the vertical dimension, the filter effective area can be maximized without increasing the horizontal footprint or the overall pellicle height. The opening area becomes independent of the height constraint.
Solution Approach 2:
The orientation parameter of the air passage opening is changed from horizontal to vertical (upward), which fundamentally changes the geometric relationship between the opening area and the pellicle height, allowing large opening areas with minimal height.
3Productivity
If the air passage opening area is enlarged for better ventilation, then pressure difference mitigation improves, but the filter size and pellicle height must be increased
Solution Approach 1:
The air passage opening is positioned to face upward, utilizing the vertical dimension for ventilation. This allows the opening area to be large without requiring increased pellicle height, as the opening extends in the vertical direction rather than consuming horizontal space.
Solution Approach 2:
The air passage design allows air to flow dynamically through the upward-oriented opening and filter, enabling efficient pressure equalization. The vertical orientation facilitates natural convection and airflow patterns that enhance ventilation efficiency.
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 design effectively cancels pressure differences across the pellicle membrane, preventing breakage and ensuring reliable operation even in vacuum environments.
Implementation Method 1
provide an air passage through the pellicle frame to communicate the inside and outside spaces with each other so that air can pass freely between these spaces
Implementation Method 2
a filter is provided to cover the air passage at the outside wall of the pellicle frame so as to prevent dust particles from entering
Implementation Method 3
a pellicle membrane having a high transmittance against the light used in the exposure process
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
There is provided a pellicle wherein the pellicle frame (21) is formed with a protrusion (29) which extends either inward or outward from the pellicle frame so that an air passage or vent hole (25) can extend in it to turn upward or downward to open in the atmosphere or in the pellicle closed space (the space interior to the pellicle frame) so that it is possible to secure a wider opening area for filtration to enable prompt air ventilation whereby the pellicle membrane does not undergo extreme inflation or deflation and thus the pellicle membrane is protected from damages.