Wafer Cassette Tray Positioning for Multi-Size Fab Transfer
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Solution Overview
Problem
Current wafer transportation systems require multiple units for different sizes and types of wafer cassettes, leading to increased production costs and limited compatibility, as existing systems are not adaptable to various wafer sizes and types within the same fab.
Innovation Solution
A transfer system comprising a tray with specific positioning features and a rail, designed to accommodate different types of wafer cassettes by utilizing a base plate with through holes and walls that separate interior and exterior regions, allowing for precise placement and compatibility with various wafer cassette sizes, including the use of RFID tags and handle structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple wafer automatic transportation units are used for different sizes of wafer cassettes, then compatibility with various wafer cassette sizes is improved, but production cost increases
Solution Approach 1:
The tray is designed with multiple positioning features (first, second, third, and fourth positioning features at different heights and positions) that can accommodate different sizes of wafer cassettes. The base plate includes a through hole with directional axes and walls that create interior and exterior regions, allowing the same tray structure to adapt to various cassette dimensions. This multi-functional design enables a single tray type to replace multiple specialized trays, reducing production costs while maintaining compatibility across different wafer cassette sizes.
2Adaptability or versatility
If multiple wafer automatic transportation units are used for different types of wafer cassettes, then adaptability to different wafer types is improved, but device complexity increases
Solution Approach 1:
The transportation unit employs a universal tray design with multiple positioning features that can handle different types of wafer cassettes. The base plate structure with through holes and walls creates a flexible positioning system that adapts to various cassette configurations without requiring separate specialized units for each wafer type.
Solution Approach 2:
The tray is segmented into multiple functional regions including the base plate, through hole with directional axes, walls creating interior/exterior regions, and four pairs of positioning features at different heights. This segmentation allows each component to contribute to accommodating different cassette types while maintaining a unified, manageable structure that reduces overall system complexity.
3Quantity of substance
If a single tray design is used for multiple wafer cassette sizes, then production cost is reduced, but positioning precision for different sizes may be compromised
Solution Approach 1:
The tray incorporates positioning features with different local qualities - four pairs of positioning features at different heights (first level height greater than second, third level height greater than fourth) and at different positions relative to the directional axes. This creates localized adaptation zones within the unified tray structure, allowing precise positioning for different cassette sizes while maintaining cost-effective single-tray production.
Data Source
AI summary
A transfer system for wafer cassettes includes a tray and a rail compatible with the tray. The tray includes a base plate, a through hole, a wall, and a pair of first positioning features. The through hole is disposed on a center of the base plate, in which the through hole has a first direction axis and a second direction axis perpendicular to the first direction axis. The wall extends from a surface of the base plate and surrounding the through hole, in which the wall separates the base plate into an interior region and an exterior region. The pair of first positioning features having a first level height are in the interior region and arranged parallel to the first direction axis.