Single Sensor Substrate Transfer Robot Positioning
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Solution Overview
Problem
Existing substrate transfer apparatuses for semiconductor fabrication require a large number of sensors to accurately detect and correct the position of wafers, leading to complex structures and increased costs due to the need for multiple sensors corresponding to each processing chamber in cluster-type systems.
Innovation Solution
A substrate transfer apparatus with a transfer robot that uses a single sensor to detect edge surfaces of substrates at specific points during extension and pivoting, allowing for the calculation of the substrate center based on these detection points, reducing the number of sensors needed and simplifying the apparatus structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are arranged along an axis traversing the wafer movement route to detect edge surfaces, then the position detection accuracy is improved, but the device complexity and cost increase due to requiring one sensor per processing chamber
Solution Approach 1:
A single sensor is designed to perform multiple detection functions by detecting wafer edge surfaces at different positions during the R-θ movement trajectory. The sensor captures detection signals at multiple points (first detection point during R movement, second detection point during θ pivoting) to calculate both radial and angular position deviations, replacing the need for multiple dedicated sensors at different locations.
Solution Approach 2:
The detection approach transitions from spatial distribution of multiple sensors to temporal sequencing of a single sensor. The sensor detects edge surfaces at different times during the wafer transfer trajectory, converting spatial detection requirements into a time-based detection sequence that achieves the same positioning accuracy with fewer components.
2Manufacturing precision
If a plurality of sensors are used to detect wafer position at each processing chamber, then the transfer accuracy is improved, but the manufacturing cost increases
Solution Approach 1:
One sensor is made to serve multiple processing chambers by detecting wafer edge surfaces at different positions along the R-θ trajectory. The sensor calculates radial position deviation from the first detection point and angular position deviation from the second detection point, enabling accurate positioning for any target chamber without requiring dedicated sensors for each chamber.
Solution Approach 2:
Multiple detection functions that would traditionally require separate sensors at different chambers are merged into a single sensor system. The sensor combines radial direction detection during R movement and angular direction detection during θ pivoting to achieve comprehensive position measurement with a single detection device.
3Productivity
If sensors are arranged to detect edge surfaces during wafer movement, then position information can be obtained without stopping, but the sensor and detection points must be collinear in the movement direction
Solution Approach 1:
The detection system adapts to the dynamic R-θ movement trajectory by positioning the sensor to detect edge surfaces at different locations during radial movement and angular pivoting. The sensor remains stationary while the wafer moves through the detection point, with detection occurring at dynamically changing positions along the trajectory rather than requiring fixed collinear arrangements.
Solution Approach 2:
The wafer edge surface itself serves as the intermediary that brings different detection points to the stationary sensor during movement. Instead of moving the sensor along a collinear path, the wafer's R-θ trajectory naturally brings various edge surface points past the fixed sensor location, eliminating the need for complex sensor movement mechanisms.
Data Source
AI summary
A substrate transfer apparatus that reduces the quantity of sensors used to detect the position of a substrate so as to simplify the structure and lower costs. The substrate transfer apparatus transfers a substrate (S) between a core chamber (11) and a peripheral chamber (12 or 13). A transfer robot (15) is arranged in the core chamber. The transfer robot includes a hand (17) for carrying the substrate and is capable of extending/drawing and pivoting the hand. A sensor (19) detects an edge surface of the substrate. The sensor is arranged at a position that the edge surface of the substrate passes by when the hand is extended/drawn between the core chamber and the peripheral chamber and that the edge surface of the substrate passes by when the hand is pivoted in the core chamber.