Variable Speed Substrate Transport Arm for Precision Handling

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Solution Overview

Problem

There is a tradeoff between increasing the moving speed of a substrate transport device to reduce transportation time and improving position accuracy, as higher speed decreases accuracy and increases particle generation due to residual oscillation.

Innovation Solution

The substrate transport device and method involve changing the lifting speed of the end effector from a first speed to a second speed when receiving a substrate, decelerating upon initial contact to enhance accuracy and then accelerating when oscillation changes to reduce oscillation and improve efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the moving speed of the end effector is increased to reduce transportation time, then productivity is improved, but manufacturing precision deteriorates due to reduced position accuracy and increased residual oscillation

Engineering Contradiction:

Improvetransportation timeVSAvoidposition accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the lifting speed variable rather than constant. The controller dynamically adjusts the lifting speed of the arm based on the operational phase: using a first (higher) speed during the approach phase and a second (lower) speed during the substrate reception phase. This dynamic speed adjustment resolves the contradiction by optimizing for both speed and precision at different moments in the transport cycle.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements periodic action by dividing the lifting process into distinct phases with different speed characteristics. The controller periodically switches between a first speed mode (for rapid approach) and a second speed mode (for precise reception). This periodic variation in operating conditions allows the system to achieve both high productivity during the approach phase and high manufacturing precision during the reception phase.

Inventive Principle:

Principle #19Periodic action

2Productivity

If the moving speed of the end effector is increased to reduce transportation time, then productivity is improved, but object-generated harmful factors worsen due to increased particle generation from residual oscillation

Engineering Contradiction:

Improvetransportation timeVSAvoidparticle generation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent converts the potential harm of high-speed movement (residual oscillation and particle generation) into a benefit by strategically timing the speed reduction. The controller intentionally reduces speed during the reception phase, transforming what would be harmful residual oscillation into controlled, minimal oscillation that prevents particle generation. The high speed during the approach phase is beneficial, and the subsequent speed reduction eliminates the harmful effects.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If the design freedom is increased to resolve the tradeoff between transportation time and position accuracy, then adaptability is improved, but device complexity increases

Engineering Contradiction:

Improvedesign freedomVSAvoidcontrol complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the lifting speed parameter during the transport process. The controller changes the speed parameter from a first speed to a second speed based on the operational phase. This parameter change approach increases design freedom by allowing flexible adjustment of motion characteristics without adding physical complexity to the mechanical structure.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback by using a detector to monitor the mount state of the substrate and a controller to adjust the lifting speed based on detection results. This feedback mechanism provides adaptability by allowing the system to respond to actual substrate conditions while maintaining relatively simple device architecture. The controller uses the detection information to dynamically adjust the lifting speed parameter.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11628565B2Substrate transport device and substrate transporting method

Publication Date: 2023.04.18 ULVAC INC

AI summary

A substrate transport device includes an arm, an end effector coupled to the arm, a driver configured to lift the arm so that the end effector receives a substrate, and a controller configured to control an output of the driver to change a lifting speed of the arm. While lifting the arm at a first speed to lift the end effector toward the substrate, the controller changes the lifting speed to a second speed that is lower than the first speed when the end effector starts to raise a height position of the substrate.