Electrostatic Chuck Temperature Control via Zone Segmentation

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Solution Overview

Problem

Existing temperature control mechanisms for electrostatic chucks face challenges in achieving local temperature control due to the presence of locally high or low temperatures in divided regions, and providing heaters on an area-by-area basis is impractical due to space and cost constraints.

Innovation Solution

A temperature control mechanism comprising a combination of heaters and thyristors, where at least one combination is provided on a zone-by-zone basis, with a power supply that supplies current to heaters through thyristors and includes filters to eliminate high-frequency power, allowing for independent temperature control of each zone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the electrostatic chuck is divided into concentric regions with one heater per region, then the structure is simple, but local temperature control performance deteriorates due to presence of locally high or low temperature portions

Engineering Contradiction:

Improveheater structureVSAvoidtemperature uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The electrostatic chuck is divided into multiple zones with independent heaters and thyristors, allowing segmented control of temperature in different regions. This segmentation enables precise local temperature adjustment to eliminate locally high or low temperature portions while maintaining overall temperature uniformity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each zone is equipped with its own heater and thyristor combination, enabling independent temperature control for each local region. This local quality approach allows different zones to have different temperature characteristics as needed, improving overall temperature distribution uniformity.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If the electrostatic chuck is divided into many areas with independent heaters for local temperature control, then temperature control performance improves, but device complexity and cost increase due to need for multiple power supplies

Engineering Contradiction:

Improvelocal temperature controlVSAvoidpower supply system

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Multiple thyristors are combined into a single power supply system, where one power supply serves multiple heater zones through the thyristor switching network. This merging reduces the number of power supplies from one-per-zone to a single shared power supply, significantly simplifying the system while maintaining independent zone control capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single power supply is designed to serve multiple functions by controlling multiple heaters through thyristors. This universal power supply can dynamically allocate power to different zones as needed, replacing the need for dedicated power supplies for each heater zone.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If thyristors are used to control current distribution to multiple heaters, then local temperature control is achieved, but high frequency power interference is generated that affects control stability

Engineering Contradiction:

Improveindependent zone controlVSAvoidcontrol stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The high frequency power generated by thyristor switching is not eliminated but converted into a useful signal for temperature control. The system utilizes this high frequency power to rapidly adjust heater output, improving responsiveness while the control algorithm processes this power dynamically to achieve stable temperature regulation.

Inventive Principle:

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

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 effective local temperature control of the electrostatic chuck, improving in-plane temperature uniformity and reducing the need for multiple power supplies, thereby optimizing resource utilization and operational efficiency.

Implementation Method 1

a power supply that supplies current to heaters through thyristors

Methodology Applied

Scientific EffectJoule Heating: Joule Heating

Implementation Method 2

a pair of filters disposed at a power supply line for supplying electric power from the power supply to the heaters and configured to eliminate high frequency power applied to the power supply

Methodology Applied

Scientific EffectElectrical Filtering: Filter (electronic)

Data Source

PatentUS10199246B2Temperature control mechanism, temperature control method and substrate processing apparatus

Publication Date: 2019.02.05 TOKYO ELECTRON LTD

AI summary

There is provided a temperature control mechanism comprising: a plurality of combinations of a heater and a thyristor, wherein at least one combination of the heater and the thyristor is provided on a zone-by-zone basis, and wherein an area of an electrostatic chuck for mounting a substrate is divided into a plurality of zones; a power supply configured to supply current to heaters of the plurality of combinations respectively through the thyristors of the plurality of combinations; a pair of filters disposed at a power supply line for supplying electric power from the power supply to the heaters and configured to eliminate high frequency power applied to the power supply.