Motor Current Compensation for Thermal Transfer Position Drift

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Solution Overview

Problem

Existing motor control methods in substrate processing apparatuses fail to compensate for displacement of objects due to heat generation, leading to inaccuracies in positioning and processing of wafers, such as abnormal film thickness distribution and temperature fluctuations.

Innovation Solution

A motor control method that acquires drive data related to motor heat generation and adjusts the current supply to compensate for displacement by calculating the number of pulses based on torque, using feed-forward control to align the target transfer position accurately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If motor control is performed without heat generation compensation, then the control system remains simple, but positioning precision deteriorates due to thermal expansion

Engineering Contradiction:

Improvepositioning precisionVSAvoidcontrol system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary action by acquiring drive data before the motor operation and calculating compensation values in advance. The controller stores compensation values corresponding to different drive data sets, and applies the appropriate compensation before positioning operations to counteract thermal expansion effects, thereby improving positioning precision without requiring complex real-time control mechanisms.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by acquiring actual drive data during motor operation and using this data to select appropriate compensation values from stored tables. The controller continuously monitors motor drive conditions and adjusts positioning commands based on pre-calculated compensation values, creating a closed-loop system that maintains precision while using relatively simple control logic.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If heat generation compensation is implemented, then positioning precision improves, but data processing complexity increases

Engineering Contradiction:

Improvetransfer position accuracyVSAvoiddata processing complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary calculation of compensation values based on drive data characteristics such as acceleration, deceleration, and speed profiles. These compensation values are stored in tables before actual positioning operations occur. During operation, the controller simply retrieves the appropriate compensation value from the stored table based on measured drive data, avoiding complex real-time calculations and reducing data processing complexity while maintaining high transfer position accuracy.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If real-time compensation calculation is performed, then positioning accuracy improves, but processing time increases

Engineering Contradiction:

Improvetransfer position accuracyVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs the computationally intensive compensation calculation in advance, before actual positioning operations are needed. Compensation values are pre-calculated based on various drive conditions and stored in lookup tables. During real-time operation, the controller only needs to retrieve the appropriate compensation value from the pre-filled table based on current drive data, dramatically reducing processing time while maintaining high transfer position accuracy.

Inventive Principle:

Principle #10Preliminary action

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 method effectively compensates for thermal expansion, ensuring precise alignment and consistent processing results by adjusting the transfer position before displacement occurs, thereby maintaining wafer quality.

Implementation Method 1

drive data which relate to the driving of the motor and vary with heat generation of the motor

Methodology Applied

Scientific EffectHeat generation: Joule Heating

Implementation Method 2

displacement of the object to be transferred from a target transfer position due to the heat generation of the motor

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12525906B2Motor control method, transfer device, and storing medium

Publication Date: 2026.01.13 TOKYO ELECTRON LTD

AI summary

A motor control method for transferring an object to be transferred by a moving object that moves by driving of a motor in a substrate processing apparatus, includes: a data acquisition process of acquiring, at different times, pieces of drive data which relate to the driving of the motor and vary with heat generation of the motor; and a transfer process of transferring the object to be transferred by controlling current to be supplied to the motor, based on each of the pieces of drive data, to compensate for displacement of the object to be transferred from a target transfer position due to the heat generation of the motor.