Load Port Mapping for Warpage-Adjusted Wafer Stack Detection
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Solution Overview
Problem
Existing mapping devices struggle to accurately detect the stored state of square-shaped plate-form objects due to the influence of warpage, which affects the detection of corners, particularly in the thickness direction, leading to inaccuracies in determining whether one or multiple objects are stacked.
Innovation Solution
A mapping device with multiple detection parts and an adjustment mechanism that accounts for warpage by using first and second detection axes to measure corner thicknesses, a third detection axis for warpage index, and an adjustment calculation unit to refine these measurements based on warpage information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a detection part detects the corner of a square shaped object, then the device can identify the object's position and orientation, but the warpage of the object causes non-negligible influence on the detected value in the thickness direction
Solution Approach 1:
The detection of corner thickness is segmented into multiple measurements: a first corner thickness detected by a first detection part, and a second corner thickness detected by a second detection part. By dividing the measurement into multiple segments and combining them, the system obtains a more reliable indicator of the object's stored state that is less susceptible to warpage effects at any single corner.
Solution Approach 2:
The patent introduces an intermediary calculation process that uses the sum or average of multiple corner thickness measurements as a mediator between the raw detection data and the final stored state determination. This intermediary value provides a more stable reference that compensates for local warpage variations, improving the reliability of the stored state identification.
2Measurement precision
If multiple detection parts are used to measure corner thicknesses, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The detection parts are designed with multi-functionality, serving both as position detectors and as thickness measurements. The same detection infrastructure is used to obtain both the corner position information and the corner thickness information, thereby reducing the need for additional specialized components and mitigating the increase in device complexity.
Solution Approach 2:
The patent merges the detection functions by using the same detection parts to obtain multiple pieces of information: corner position, corner thickness, and by extension, the stored state of the object. This combining of multiple detection functions into unified detection parts helps control device complexity while maintaining measurement precision.
3Measurement precision
If the detection axis moves along the first direction to detect corner thickness, then the thickness measurement is obtained, but the warpage effect cannot be eliminated
Solution Approach 1:
The patent applies local quality by making different parts of the detection system serve different functions: the first and second detection parts measure corner thicknesses at specific locations, while the calculation unit processes these local measurements to derive a global indicator of the stored state. By optimizing the detection at specific critical corners and using the combination of measurements, the system compensates for local warpage effects.
Solution Approach 2:
The detection approach uses asymmetry by measuring corners that are positioned differently relative to the expected warpage patterns. By selecting specific corners (first corner and second corner) and measuring their thicknesses, the system creates an asymmetric measurement pattern that, when combined, provides information that is less sensitive to the symmetric warpage deformation that typically affects plate-form objects.
Data Source
AI summary
A mapping device capable of detecting a stored state of a square shaped plate-form object including: a first detection part having a first detection axis which crosses a first side and a second side perpendicular to the first side object to detect a first corner thickness; a second detection part having a second detection axis which crosses the first and third sides of the object to detect a second corner thickness; a first information acquiring unit acquiring a first information relating to a warpage amount in the first direction of the object; an adjustment calculation unit calculating an adjusted detection value relating to the thickness of the object in the first direction by adjusting, based on the first information, a sum of the first and second corner thicknesses or an average thereof; and a distinguishing unit distinguishing the stored state of the object using the adjusted detection value.