Substrate Transfer Robot Position Sensor Using Partial Beam Blocking
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Solution Overview
Problem
Conventional substrate transfer robots in semiconductor processing systems face challenges with substrate drift due to interference from robot arms with light beams emitted by photosensors, overlapping substrates, and distorted position calculations, leading to inaccurate placement and potential damage.
Innovation Solution
The implementation of a substrate handling system with a pair of position sensors and an elongated end effector, where the end effector's design allows its edge to partially block light beams from sensors, enabling precise substrate positioning and accurate calculation of substrate position, while the control system adjusts movements based on light reception levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photosensors are used to detect substrate position, then substrate placement accuracy can be improved, but robot arms interfere with light beams causing measurement errors
Solution Approach 1:
The patent transitions from using a single photosensor to using multiple photosensors arranged in different spatial positions. This dimensional change allows the system to detect substrate position from multiple angles simultaneously, enabling the control system to calculate accurate position information even when some sensors are blocked by robot arms during transfer operations.
2Device complexity
If a single photosensor is used, then device complexity is reduced, but position measurement accuracy deteriorates due to interference and overlapping substrates
Solution Approach 1:
The patent divides the position detection function into multiple independent photosensors rather than relying on a single sensor. Each photosensor provides partial measurement data, and the control system integrates these segmented measurements to achieve complete and accurate position information, resolving the contradiction between simplicity and precision.
3Productivity
If robot moves fast to improve productivity, then substrate transfer speed increases, but substrate drift occurs leading to placement errors
Solution Approach 1:
The patent implements a feedback mechanism where multiple photosensors continuously monitor substrate position during transfer operations. The control system receives real-time position data from these sensors and dynamically adjusts robot movement to compensate for substrate drift, enabling high-speed transfer while maintaining placement accuracy through closed-loop control.
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
This solution enhances the accuracy of substrate placement, reduces the risk of damage, and improves the overall efficiency of substrate handling by minimizing interference and ensuring consistent substrate positioning relative to the end effector.
Implementation Method 1
Each of the sensors comprises a light beam emitter configured to emit a beam of light, and a receiver configured to receive the light beam
Implementation Method 2
an edge of a substrate held in the expected position by the end effector to partially block a light beam emitted from the emitter of one of the position sensors
Data Source
AI summary
A substrate processing apparatus comprises a substrate handling chamber, a pair of position sensors, and a substrate transfer robot. Each of the sensors comprises an emitter configured to emit a beam of light, and a receiver configured to receive the light beam. The substrate transfer robot comprises an end effector and a robot actuator. The end effector is configured to hold a substrate such that the substrate has a same expected position with respect to the end effector every time the substrate is held. The robot actuator is configured to move the end effector within the handling chamber to transfer substrates among a plurality of substrate stations. An edge of a substrate held in the expected position by the end effector can partially block a light beam of one of the position sensors, while another end of the end effector partially blocks a light beam of the other position sensor.