Heater Signal Filtering for Precise Substrate Temperature Control

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Solution Overview

Problem

The accuracy of heater temperature control in substrate processing apparatuses is compromised by noise in the detected voltage and current signals, leading to inaccurate resistance value calculations and subsequent temperature control.

Innovation Solution

A substrate processing apparatus equipped with a digital filter to remove noise from detection voltage and current signals, using a digital filter to attenuate noise components, allowing for precise heater resistance value calculation and improved temperature control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If noise filtering is applied to detection voltage and current signals, then measurement precision of heater resistance improves, but device complexity increases due to addition of digital filter

Engineering Contradiction:

Improveheater resistance measurement precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

A digital filter is introduced as an intermediary component between the detection circuit and the control algorithm. The digital filter processes the detection voltage and current signals to remove noise components before these signals are used to calculate heater resistance, thereby improving measurement precision without requiring changes to the fundamental heating control mechanism

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces potential hardware-based noise filtering approaches with a digital filter implemented in the control unit. This substitution allows noise removal to be achieved through software algorithms rather than additional physical filtering components, improving measurement precision while minimizing increases in device complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If digital filter is added to filter detection signals, then temperature control accuracy improves, but device complexity increases

Engineering Contradiction:

Improvetemperature control accuracyVSAvoiddevice complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control unit is designed to perform multiple functions: it controls the heater power supply, processes detection signals through digital filtering, calculates heater resistance, and adjusts temperature control parameters. By making the control unit multi-functional, the patent improves temperature control accuracy without requiring separate dedicated components for each function, thereby minimizing the increase in device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If noise is removed from detection signals through digital filtering, then reliability of temperature control improves, but loss of information increases due to signal processing

Engineering Contradiction:

Improvetemperature control reliabilityVSAvoidsignal information loss

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The digital filter is configured to remove only the noise components from the detection signals while preserving the essential signal information needed for accurate temperature control. By applying partial filtering action that targets specifically the harmful noise frequencies rather than attenuating all signal variations, the patent improves reliability while minimizing information loss

Inventive Principle:

Principle #16Partial or excessive 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

Enhances the accuracy of heater temperature control by filtering out noise, thereby improving the precision of resistance value determination and overall temperature management.

Implementation Method 1

a digital filter configured to filter at least one of a detection voltage, which is a digital voltage value detected as a voltage applied to the heater resistor, or a detection current, which is detected as a voltage calculated from the heater resistor and a current flowing in the heater resistor and converted into a digital voltage value

Methodology Applied

Scientific EffectDigital filtering: Filter (electronic)

Implementation Method 2

a heater resistor; a digital filter configured to filter at least one of a detection voltage, which is a digital voltage value detected as a voltage applied to the heater resistor

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS12424416B2Substrate processing apparatus and parameter acquisition method

Publication Date: 2025.09.23 TOKYO ELECTRON LTD

AI summary

A substrate processing apparatus includes a heater resistor; a digital filter configured to filter at least one of a detection voltage, which is a digital voltage value detected as a voltage applied to the heater resistor, or a detection current, which is detected as a voltage calculated from the heater resistor and a current flowing in the heater resistor and converted into a digital voltage value; and a controller configured to control a temperature of the heater resistor with the detection voltage and the detection current, at least one of the detection voltage or the detection current being filtered by the digital filter.