Wafer Container Latch Mechanism with Roller Cam Follower
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Solution Overview
Problem
Conventional latching mechanisms for large semiconductor wafer containers, such as those for 450 mm wafers, face challenges with increased torque requirements and particulation issues due to higher forces needed for securement and sealing, which are not adequately addressed by existing designs.
Innovation Solution
A latch mechanism with a cammed plate and roller cam follower system, where the roller axle is supported at both ends to prevent binding, and alignment structures ensure efficient motion translation, reducing torque requirements and minimizing particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional latching mechanisms are used for large diameter wafers (450 mm), then securement forces and gasket compression are achieved, but torque requirements increase and particulation issues occur
Solution Approach 1:
The patent replaces conventional sliding or rubbing mechanical interfaces with a roller-based rolling contact system. The roller element converts sliding friction into rolling friction, significantly reducing the force required for latching operations and minimizing particle generation from component wear and contact.
Solution Approach 2:
The patent changes the fundamental parameter of contact interaction from sliding/rubbing to rolling. This parameter change reduces the coefficient of friction and the resulting torque requirements, while also reducing the generation of particulate matter from component wear.
2Reliability
If greater closure forces are applied to secure 450 mm wafers, then wafer securement and gasket sealing are improved, but door latching becomes more difficult
Solution Approach 1:
The roller mechanism substitutes high-friction sliding contact with low-friction rolling contact, enabling the application of greater closure forces for improved sealing while keeping the operational torque within acceptable limits. The rolling contact reduces the mechanical resistance during latching operations.
Solution Approach 2:
By changing the contact mechanism from sliding to rolling, the patent alters the friction parameter, allowing higher securement forces to be applied without proportionally increasing the torque required for operation. This enables reliable sealing while maintaining ease of latching.
3Device complexity
If rubbing components are used in the latching mechanism, then simple mechanical design is achieved, but particle generation increases
Solution Approach 1:
The patent substitutes rubbing/sliding mechanical interfaces with a roller-based rolling contact system. This substitution eliminates the direct rubbing between components, dramatically reducing particle generation from wear while maintaining relatively simple mechanical design through the use of a single roller element.
Solution Approach 2:
The roller acts as an intermediary element between the latching components, preventing direct rubbing contact. This intermediary rolling element transfers the latching force while minimizing wear and particle generation from component-to-component contact.
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 solution provides secure door closing and latching with reduced torque requirements and minimizes particle generation, enhancing the performance and cleanliness of the wafer container system.
Implementation Method 1
A latch mechanism with a cammed plate and roller cam follower system, where the roller axle is supported at both ends to prevent binding
Data Source
AI summary
A wafer container with a latch mechanism that provides sealing for large wafer containers, such as for 450 mm wafers, accomplishes secure door closing and latching with reduced torque requirements for rotating the central rotatable cam plate. In various embodiments, a camming slot formed in the rotatable cammed plate is arcuate and defined by opposing cam surfaces which are selectively engaged by a cam follower, such as a roller, attached to a proximal end of a latch arm. The roller can include unitary axle portions that snap into the proximal end of the latch arm and is supported at both axial ends of the roller. The proximal end of the latch arm can include parallel extensions separated by a gap, and have guide in surfaces to deflect the extensions as the axle portions of the roller are forced into position thereby seating the roller at both axial ends.