Reticle Pod Cover Baseplate Alignment Pin Recess
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Solution Overview
Problem
In the context of extreme ultraviolet (EUV) photolithography, existing reticle containers face challenges with particulate generation and entrapment due to sliding friction and outgassing, which can damage delicate reticle surfaces and compromise the quality of semiconductor devices.
Innovation Solution
The implementation of alignment structures with reduced area contact between components, utilizing finely machined and polished metal-to-metal flat planar sealing surfaces, along with alignment pins and resilient seals, to minimize particulate generation and ensure hermetic sealing, thereby reducing the risk of contamination and damage during storage, transport, and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional alignment structures with larger contact areas are used between cover and base, then easier alignment and assembly are achieved, but particulate generation increases due to sliding friction
Solution Approach 1:
The patent employs curved or rounded alignment features (such as rounded corners on the base and corresponding curved alignment surfaces on the cover) instead of sharp edges or flat surfaces. This curvature reduces stress concentration and minimizes particulate generation during the alignment and sealing process while maintaining ease of assembly.
2Ease of manufacture
If polymer materials are used in reticle containers, then ease of manufacture and cost reduction are achieved, but outgassing and moisture desorption occur which can damage reticles
Solution Approach 1:
The patent specifies precise dimensional parameters and tolerance ranges for the alignment features (e.g., alignment feature dimensions, positional tolerances, surface flatness) to ensure proper engagement between cover and base. These parameter controls maintain manufacturing feasibility while achieving the required hermetic sealing to prevent outgassing and moisture desorption issues.
3Reliability
If hermetic sealing is achieved through extensive contact surfaces between cover and base, then sealing reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent divides the sealing function into discrete, localized alignment features (such as individual alignment pins, recesses, or protrusions) rather than relying on extensive continuous contact surfaces. This segmentation concentrates the sealing function at specific points, reducing the overall manufacturing precision requirements while maintaining hermetic sealing reliability.
4Object-generated harmful factors
If alignment features with point or line contact are used, then particulate generation is reduced, but alignment precision and dimensional control become more difficult
Solution Approach 1:
The patent introduces intermediary alignment features (such as alignment pins, dowels, or tapered features) that act as mediators between the cover and base. These intermediary elements provide precise alignment and dimensional control through their geometry and fit, while their localized contact points minimize sliding friction and particulate generation compared to large surface contacts.
Data Source
AI summary
An alignment system for aligning the cover and base of an inner pod of a reticle carrier. The cover and base can each be provided with hard planar surface seal zones on the bottom surface and the top surface, respectively. The cover of the inner pod may be provided with a through hole or a blind hole into which an alignment pin is disposed. The base is provided with a guide recess to receive the distal end of the alignment pin. The alignment pin operates to limit contact surface area between the cover and the base during that is in sliding contact, thus inhibiting particulate generation. Low particulate-generating materials, such as stainless steel or polyamide-imide, can also be utilized to further reduce particulate generation. Furthermore, the cover and base can each be unitary without need for fastening components thereto, thereby eliminating clamped surfaces that can entrap and subsequently shed particulates.