Movable Projections for Workpiece Edge Access and Alignment
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Solution Overview
Problem
Existing workpiece carriers obstruct the edges of workpieces during processing, requiring additional steps for edge treatment and potentially reducing efficiency due to misalignment issues with masks caused by thermal expansion and other factors.
Innovation Solution
A carrier with movable projections and an alignment apparatus that allows precise positioning of workpieces within cells without obstructing their edges, using multiple-step alignment to ensure accurate placement and mask alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the carrier holds or envelops the edges of the workpieces, then the workpiece is protected during transitions, but the edges are blocked or obscured during processing, requiring additional steps and reducing efficiency
Solution Approach 1:
The carrier is divided into separate cells, each with independent movable projections that can be positioned to contact only specific edges of workpieces. This segmentation allows selective edge support without complete envelopment, enabling edge access for processing while maintaining protection during transitions.
Solution Approach 2:
The movable projections can dynamically adjust their position and configuration based on the processing requirements. During transitions, projections are positioned to protect workpiece edges; during processing, they can be repositioned to allow edge access while maintaining workpiece support.
2Manufacturing precision
If a mask is placed in front or on top of the workpiece to limit exposure to energy, then processing precision is improved, but alignment accuracy is compromised by thermal expansion and other errors
Solution Approach 1:
Alignment pins serve as intermediary reference elements between the carrier and the mask. These pins provide stable, thermally-matched reference points that are not subject to the same thermal expansion issues as the mask or workpiece, enabling accurate alignment even during thermal processing cycles.
Solution Approach 2:
The system accounts for and compensates for thermal expansion by using reference pins made from materials with matched thermal expansion coefficients. By changing the material parameter selection, the alignment reference remains stable while other components expand or contract during processing.
3Device complexity
If the carrier uses fixed structures to hold workpieces, then alignment is simplified, but the workpiece edges are obscured and complete processing cannot be performed
Solution Approach 1:
The movable projections replace fixed holding structures with dynamic, adjustable elements. These projections can be positioned to contact only the necessary portions of the workpiece for alignment and support, leaving edges exposed for complete processing while maintaining simple alignment procedures.
Data Source
AI summary
A carrier capable of holding one or more workpieces is disclosed. The carrier includes movable projections located along the sides of each cell in the carrier. This carrier, in conjunction with a separate alignment apparatus, aligns each workpiece within its respective cell against several alignment pins, using a multiple step alignment process to guarantee proper positioning of the workpiece in the cell. First, the workpieces are moved toward one side of the cell. Once the workpieces have been aligned against this side, the workpieces are then moved toward an adjacent orthogonal side such that the workpieces are aligned to two sides of the cell. Once aligned, the workpiece is held in place by the projections located along each side of each cell. In addition, the alignment pins are also used to align the associated mask, thereby guaranteeing that the mask is properly aligned to the workpiece.