Servo Transfer Position Recovery for Low-Power Substrate Handling

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Solution Overview

Problem

The power consumption of transfer devices in substrate processing apparatuses, which are controlled by servo motors, is high due to the continuous operation of servo motors during processing steps where no transfer is needed.

Innovation Solution

The implementation of a power saving controller that allows servo motors to be turned off during idle periods and resumes servo control from a recorded absolute position when the system is powered back on, reducing unnecessary power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If servo motors are continuously operated to maintain positioning accuracy, then positioning reliability is improved, but power consumption increases

Engineering Contradiction:

Improvepositioning reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The absolute position holder records the absolute position information before the servo motor is turned off. This preliminary action ensures that when the servo motor restarts, the system can immediately resume from the recorded position without needing to return to origin or perform position re-detection, thus maintaining positioning reliability while reducing power consumption during idle periods.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the traditional relative position detection system with an absolute position detection system. The absolute position holder stores absolute position information independently of the servo motor's power state, eliminating the need for continuous servo operation to maintain position awareness. This substitution allows the servo motor to be turned off during idle periods while preserving positioning accuracy upon restart.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Use of energy by moving object

If servo motors are turned off during idle periods, then power consumption is reduced, but positioning accuracy may be lost

Engineering Contradiction:

Improvepower consumptionVSAvoidpositioning accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The absolute position holder creates a copy of the absolute position information and stores it in non-volatile memory. This copied position data persists even when the servo motor is powered off, allowing the system to restore accurate positioning information upon restart without requiring continuous power to the servo motor or encoder.

Inventive Principle:

Principle #26Copying

3Measurement precision

If absolute position is recorded continuously, then positioning accuracy is maintained, but memory usage and system complexity increase

Engineering Contradiction:

Improvepositioning accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the absolute position recording function from the main servo control system and places it in a separate absolute position holder. This modular approach allows the servo motor to be turned off independently while the absolute position holder maintains position information. The separation reduces the complexity burden on the main control system while preserving positioning accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the state of position information from relative (requiring continuous power and reference) to absolute (self-contained and persistent). By storing absolute position values in non-volatile memory, the system maintains positioning accuracy without requiring continuous power or complex reference systems, thereby reducing overall system complexity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12283501B2Substrate processing apparatus, method of manufacturing semiconductor device, method of processing substrate, and recording medium

Publication Date: 2025.04.22 KOKUSAI DENKI KK

AI summary

An object transfer device includes: a motor; a motor drive circuit; an encoder that detects a motor output shaft rotation angle; a drive system that transmits motion of the output shaft to an object; an origin sensor that detects arrival of a predetermined site of the drive system interlocked with the object at a predetermined position; a drive circuit-including servo amplifier that records a current position of the object based on detection by the encoder and the origin sensor, and controls the object to a target position; an absolute position holder that acquires an absolute position of the predetermined site based on detection by the encoder at least while the drive circuit is off; and a power saving controller that is bidirectionally communicable with the servo amplifier and can resume servo control with the absolute position as a current position of the predetermined site when the drive circuit is on.