Multi-Zone Substrate Support Temperature Control Without Thermocouples

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Solution Overview

Problem

Existing substrate support units face challenges in accurately measuring and controlling temperature across different zones, particularly due to limitations with thermocouples that can only measure local temperatures and struggle with installing sensors in edge areas, leading to inefficient substrate processing.

Innovation Solution

A substrate support unit utilizing resistance elements in each zone with a DC supply unit and control unit to measure and adjust temperatures using DC voltage, allowing for accurate temperature calculation and control across multiple areas, and incorporating an insulation member to prevent leakage current and enhance ESC chucking efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a thermocouple is used to measure temperature in the center area, then the temperature of the center area can be measured, but the temperature of the edge area cannot be accurately measured

Engineering Contradiction:

Improvetemperature measurement accuracyVSAvoidsensor installation feasibility

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical contact-based thermocouple measurement system with an electrical resistance-based temperature measurement system. The resistance element serves dual purposes: heating the substrate and measuring its temperature through resistance changes, eliminating the need for separate temperature sensors and their associated wiring infrastructure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The resistance element is designed to perform multiple functions simultaneously: it acts as both the heating source for the substrate and the temperature sensing element. This multi-functional design allows temperature measurement at multiple zones (center and edge areas) without requiring separate sensor installations in each location.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Temperature

If AC voltage is used to heat the substrate, then the substrate can be heated, but leakage current is generated

Engineering Contradiction:

Improvesubstrate heating capabilityVSAvoidleakage current

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent changes the electrical parameter from AC voltage to DC voltage for heating the substrate. This parameter change eliminates the leakage current issue inherent in AC-based heating systems while maintaining the substrate heating capability. The DC voltage applied to the resistance element provides stable heating without the parasitic leakage currents associated with AC systems.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the substrate support unit is divided into multiple zones with separate heater units, then each zone can be heated independently, but accurate temperature control in each zone becomes difficult

Engineering Contradiction:

Improvezonal heating capabilityVSAvoidzonal temperature measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The substrate support unit is divided into multiple zones (center area and edge area), with separate resistance elements in each zone. Each resistance element can be independently controlled and measured, allowing for zonal heating and temperature monitoring. The control unit can adjust the voltage applied to each resistance element separately to achieve desired temperature distributions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements feedback control by continuously monitoring the resistance values of the resistance elements and adjusting the applied voltage accordingly. The control unit measures the resistance changes in real-time and uses this feedback to maintain precise temperature control in each zone, ensuring that temperature deviations are corrected automatically.

Inventive Principle:

Principle #23Feedback

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 enables precise temperature measurement and control in each area, improves process efficiency by handling temperature changes effectively, and reduces leakage current, resulting in enhanced substrate processing and increased ESC chucking efficiency.

Implementation Method 1

a resistance element provided in the susceptor to heat the substrate

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a control unit for calculating a temperature of the resistance element by measuring a voltage value and a resistance value of the resistance element

Methodology Applied

Scientific EffectResistive temperature sensing: Electrical Resistance

Data Source

PatentUS20230376055A1Substrate supporting unit and temperature control method thereof

Publication Date: 2023.11.23 TES CO LTD

AI summary

The present invention relates to a substrate support unit and a temperature control method of the substrate support unit, and more specifically, to a substrate support unit and a temperature control method of the substrate support unit, which can accurately measure and adjust the temperature of each zone when the substrate support unit that supports and heats a substrate is divided into a plurality of zones.