Wafer Transfer Apparatus Tri-Sensor Edge Detection Notch Interference
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Solution Overview
Problem
Wafer transfer processes often result in measurement errors due to notches on the wafer, which can lead to improper positioning during subsequent processes, affecting the accuracy of semiconductor manufacturing.
Innovation Solution
An apparatus and method utilizing three sensors to detect the edges of a wafer, determine if any edge points are from a notch, and calculate the wafer center using combinations of detected points, allowing for precise alignment and correction of the wafer's position before transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional single-point or two-point detection methods are used to detect wafer edge, then the device complexity is low, but measurement precision deteriorates due to notch interference
Solution Approach 1:
The wafer edge detection is segmented into three separate detection points arranged in a triangular pattern, rather than using a single or two-point detection method. This segmentation allows the system to identify and exclude notch points by comparing multiple discrete measurements, thereby improving measurement precision while managing device complexity through a straightforward sensor arrangement.
2Measurement precision
If three sensors are used to detect wafer edge points, then measurement precision improves by identifying notch points, but device complexity increases
Solution Approach 1:
The controller uses feedback logic to analyze the three detected edge points, identifying whether any point corresponds to a notch based on geometric relationships. The system processes the coordinates from all three sensors, applies computational geometry algorithms to detect anomalies, and uses this feedback to determine the accurate wafer center position, thereby improving measurement precision through intelligent data processing.
3Manufacturing precision
If wafer position is not verified before transfer, then the transfer process is fast, but manufacturing precision deteriorates due to improper positioning
Solution Approach 1:
The system performs preliminary detection of three edge points and calculation of the wafer center position before the transfer operation. By verifying the wafer positioning accuracy in advance using the triangular sensor arrangement and identifying any notch points, the system ensures proper positioning is confirmed before transfer, thereby improving manufacturing precision without significantly impacting productivity.
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 effectively reduces measurement errors caused by notches, ensuring accurate wafer positioning and enhancing the reliability of semiconductor device manufacturing processes.
Implementation Method 1
three sensors each including a light emitter installed on the first support and a light receiver installed on the sensor support, the three sensors respectively configured to detect three points of an edge of the wafer
Data Source
AI summary
An apparatus for transferring a wafer includes a main body, a first support installed in the main body, a sensor support fixed to the first support, a finger member slidably installed along the first support to transfer the wafer and positioned at a lower level than the sensor support, three sensors each including a light emitter installed on the first support and a light receiver installed on the sensor support, the three sensors respectively configured to detect three points of an edge of the wafer seated on the finger member, and a controller connected to the three sensors, wherein the controller is configured to determine whether any of the three points of the edge of the wafer is detected from a notch of the wafer based on signals received from the sensors.