Pellicle Frame Notch Design for EUV Ventilation and Film Protection
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Solution Overview
Problem
Existing pellicle frames for EUV exposure face challenges such as damage from pressure changes, difficulty in cleaning, and potential damage from strong adhesives, while also requiring a large ventilation area and being prone to dust generation due to metal contact.
Innovation Solution
A pellicle frame with a notched part on its upper end face, reducing the bonded area with the pellicle film, allowing for the use of strong adhesives without risk of film damage, and featuring a design that minimizes the need for through holes, thus enhancing ventilation and ease of cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a filter is provided on an upper end face or lower end face of a pellicle frame to achieve wide ventilation area, then ventilation area is improved, but curved parts are generated in ventilation passage causing large resistance and pressure difference that may damage the pellicle film
Solution Approach 1:
The pellicle frame is divided into multiple ventilation holes distributed across its structure, breaking the ventilation function into multiple small openings rather than one large opening with curved passages. This segmentation eliminates curved parts while achieving sufficient total ventilation area.
Solution Approach 2:
Ventilation holes are provided not only on the upper and lower end faces but also on the side faces of the pellicle frame, utilizing multiple dimensions to distribute ventilation openings. This three-dimensional arrangement achieves wide ventilation area without requiring curved passages in any single plane.
2Ease of manufacture
If pressure-sensitive adhesive layer is used as airtight gasket to attach pellicle film to pellicle frame, then ease of manufacture is improved, but foreign matters may remain in curved parts of ventilation passage and cleaning becomes difficult
Solution Approach 1:
The ventilation system is segmented into multiple small holes rather than large curved passages, making each individual hole easy to clean and free from foreign matter accumulation. The segmented structure eliminates the cleaning difficulties associated with curved passages.
Solution Approach 2:
Instead of creating large curved passages that are difficult to clean, the design inverts the approach by using multiple small straight holes that are trivial to clean. This inversion transforms a cleaning problem into a simple maintenance feature.
3Reliability
If bonded area between pellicle frame and pellicle film is reduced to allow strong adhesive use, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The pellicle frame features locally enlarged areas at specific positions where pellicle films are to be attached. This local quality enhancement provides sufficient bonded area for strong adhesive bonds only where needed, while maintaining reduced bonded area elsewhere for reliability.
Solution Approach 2:
The bonded area parameter is changed from uniform distribution to concentrated localization at specific attachment positions. This parameter change allows strong adhesives to be used effectively at critical locations without requiring large total bonded area, thus maintaining reliability while managing manufacturing precision.
Data Source
AI summary
The present invention is to provide a pellicle frame in a frame shape, having an upper end face to arrange a pellicle film thereon and a lower end face to face a photomask, and which is characterized by being provided with a notched part from an outer side face toward an inner side face of the upper end face, and to provide a pellicle characterized by including the pellicle frame as a component.