Substrate Conveying Robot Laser Displacement Sensor
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Solution Overview
Problem
Conventional substrate conveying robots face challenges in accurately detecting the vertical position of substrates due to mounting errors of optical sensors, making precise robot operation difficult.
Innovation Solution
A substrate conveying robot equipped with a robot arm, an end effector having a substrate holding unit, an elevating drive unit, and a substrate detection sensor that elevates coordinately with the end effector to detect the vertical position of substrates, allowing for precise control of robot operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a substrate pitch in the vertical direction is reduced to increase the number of treated wafers and enhance storing sufficiency, then productivity is improved, but measurement precision deteriorates due to increased difficulty in detecting substrate positions
Solution Approach 1:
The patent replaces the conventional optical sensor-based detection system with a laser displacement sensor that uses optical interference principles to measure substrate positions. This substitution enables high-precision measurement (0.1μm accuracy) even when substrate pitch is reduced, allowing increased productivity without sacrificing measurement precision.
Solution Approach 2:
The patent changes the detection parameter from simple optical presence/absence detection to precise distance measurement using laser interference. By measuring the distance between the substrate surface and the end effector with high precision, the system can accurately detect substrate positions even at reduced pitch, enabling both high productivity and high measurement precision.
2Ease of operation
If an optical sensor is mounted on the end effector to detect substrate presence, then ease of operation is improved, but measurement precision deteriorates due to mounting errors
Solution Approach 1:
The patent replaces the mounted optical sensor with a laser displacement sensor that measures distance based on optical interference. This eliminates the mounting error issue because the measurement is based on physical distance measurement rather than optical detection from a mounted sensor position.
Solution Approach 2:
The patent introduces a laser beam as an intermediary between the end effector and the substrate for measurement. The laser displacement sensor measures the distance by detecting the interference pattern of laser light, serving as an intermediary that eliminates the need for direct optical sensor mounting on the end effector.
3Measurement precision
If a substrate detection sensor is provided separately from the end effector, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the laser displacement sensor with the elevating drive unit structure. The sensor is integrated into the existing mechanical framework, utilizing the elevating mechanism's movement for both positioning and measurement purposes. This combining approach improves measurement precision while avoiding significant increases in device complexity.
Data Source
AI summary
A substrate conveying robot has a robot arm including an end effector having a substrate holding unit holding a substrate, arm drive unit for driving the robot arm, an elevating drive unit for elevatingly driving the end effector, a robot control unit controlling the arm drive unit, the elevating drive unit, and the substrate holding unit, and a substrate detection unit having a substrate detection unit which detects a vertical position of the substrate and elevates coordinately with an elevating operation of the end effector. By this configuration, a vertical position of a substrate to be conveyed is detected with high accuracy so that a robot operation can be controlled based on the detection result.