Reticle Container Tapered-Corner Latch for Low-Particle Handling
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Solution Overview
Problem
The generation of particles due to friction between the inner pod cover and base plate in mask carriers during opening and closing, which can damage masks or blank substrates and cause image errors in photolithography processes.
Innovation Solution
A novel configuration of the mask inner pod with tapered corners, ball-shaped members, and biasing members to prevent direct contact and friction between the inner pod cover and base plate, using polymer materials to minimize particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the inner pod cover and base plate are made of metal materials (aluminum alloy with nickel, chromium coatings) to enhance mechanical properties and control weight, then the strength and durability are improved, but friction between the components generates metal particles that contaminate the mask or blank substrate
Solution Approach 1:
A polymer layer is introduced as an intermediary between the metal inner pod cover and base plate. This polymer intermediary maintains the mechanical strength requirements while preventing direct metal-to-metal contact, thereby eliminating particle generation during opening and closing operations
Solution Approach 2:
The inner pod cover and base plate are constructed as composite structures combining metal substrates (aluminum alloy with nickel/chromium coatings) with polymer surface layers. This composite approach provides the necessary mechanical properties from the metal core while the polymer surface prevents friction-based particle generation
2Manufacturing precision
If the inner pod cover and base plate are designed to fit each other with high accuracy to ensure proper closure, then the sealing and protection are improved, but positional inaccuracy or dimensional variations cause contact and friction between the components
Solution Approach 1:
The polymer layer thickness and material properties are optimized to compensate for dimensional variations and positional inaccuracies in the metal components. This parameter adjustment allows the cover and base plate to accommodate manufacturing tolerances without causing harmful friction contact
Solution Approach 2:
The polymer layer serves as a pre-designed cushioning element that absorbs and distributes contact forces before they can cause damage. This beforehand cushioning prevents direct metal-to-metal contact even when positional inaccuracy occurs during assembly or operation
3Object-generated harmful factors
If the inner pod cover and base plate are made of polymer materials to prevent particle generation, then the particle contamination is reduced, but the mechanical strength and durability may be compromised
Solution Approach 1:
The inner pod cover and base plate use composite construction with metal substrates providing structural strength and polymer surface layers providing particle-free operation. This composite approach simultaneously achieves both mechanical durability and contamination prevention
Solution Approach 2:
Different regions of the inner pod structure have different material properties: the bulk metal provides mechanical strength where needed, while the polymer coating provides particle-free surfaces where contact occurs. This local differentiation optimizes both strength and contamination prevention
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
Reduces particulate contamination and image errors in photolithography, lowering the cost of defect checking and enhancing the reliability of mask transport and storage.
Implementation Method 1
a biasing member and a ball-shaped member located in the tapered corners of the base. The ball-shaped member mates with the recess when the cover is attached to the base
Data Source
AI summary
A mask container for storing a mask for photolithography, includes a cover and a base having a plurality of tapered corners. The tapered corners taper outward and downward from a top major surface of the base. The cover having the tapered corners extends downward that covers the tapered corners of the base when the cover is attached to the base. The tapered corners of the cover are tapered at about the same angle as the tapered corners of the base so that a surface of the tapered corners of the cover is substantially parallel to a corresponding surface of the tapered corner of the base when the cover is attached to the base. A recess is located in the tapered corners of the cover. A biasing member and a ball-shaped member are located in the tapered corners of the base to mate with the recess when the cover is attached to the base.