Electrostatic Chuck Backside Gas Pressure Calculation for Wafer Cooling

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Solution Overview

Problem

In semiconductor manufacturing processes using plasma processing devices, there is a lack of means to accurately grasp the wafer back-surface pressure, which is crucial for achieving uniform surface temperature and detecting abnormalities in the adsorption force of electrostatic chuck devices.

Innovation Solution

The electrostatic chuck device incorporates a gas supplying line with a flow rate resistive element, allowing for the calculation of wafer back-surface pressure based on the primary side pressure of the flow rate resistive element, the flow rate of the thermally conductive gas, and the flow characteristic of the resistive element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If multiple gas supplying ports are provided to supply thermally conductive gas to the gap between the wafer and adsorption plate, then heat conduction efficiency is improved, but there is no means to grasp the wafer back-surface pressure

Engineering Contradiction:

Improveheat conduction efficiencyVSAvoidwafer back-surface pressure information

Core Design Contradiction:

Loss of energyVSLoss of information

Solution Approach 1:

A flow rate resistive element is introduced as an intermediary component in the gas supplying line. This element creates a known flow resistance that allows the system to calculate wafer back-surface pressure by measuring the pressure difference across the resistive element and using the known flow rate characteristic. The resistive element acts as a mediator that converts unmeasurable pressure information into measurable pressure differential information.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements feedback by continuously measuring the primary side pressure of the flow rate resistive element and using this information to calculate the wafer back-surface pressure. The pressure calculation section processes the measured pressure data along with the known flow rate and flow characteristic to provide real-time feedback on the wafer back-surface pressure, enabling monitoring and control.

Inventive Principle:

Principle #23Feedback

2Measurement precision

If a flow rate resistive element is added to calculate wafer back-surface pressure, then pressure monitoring capability is improved, but device complexity increases

Engineering Contradiction:

Improvewafer back-surface pressure measurementVSAvoidgas supplying line structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system changes the parameter measurement approach by measuring the primary side pressure of the flow rate resistive element instead of directly measuring the wafer back-surface pressure. By utilizing the known flow rate and flow characteristic of the resistive element, the system calculates the secondary side pressure (wafer back-surface pressure) through parameter transformation, avoiding the need for direct pressure sensors in the gap.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces a direct mechanical pressure measurement system (which would require sensors in the gap) with a calculation-based system. By using the flow rate resistive element's known characteristics and measuring only the primary side pressure, the system substitutes complex mechanical sensing with a computational approach that uses fluid dynamics principles.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 configuration enables accurate calculation and monitoring of wafer back-surface pressure, improving the precision of processing dimensions and enabling early detection of abnormalities in the electrostatic chuck device.

Implementation Method 1

a flow rate resistive element that acts as a resistance in case that the thermally conductive gas flows

Methodology Applied

Scientific EffectFlow rate resistance: Pressure Drop

Implementation Method 2

an electrostatic chuck device that adsorbs an object by electrostatic force

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Implementation Method 3

a gas supplying line that supplies a thermally conductive gas to a gap between the adsorption surface and an adsorbed surface of the object

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS12327750B2Electrostatic chuck device, pressure calculation method and program

Publication Date: 2025.06.10 HORIBA STEC CO LTD

AI summary

An electrostatic chuck device for adsorbing an object by electrostatic force comprises an adsorption plate that has an adsorption surface to adsorb the object, a gas supplying line that supplies a thermally conductive gas to a gap between the adsorption surface and an adsorbed surface of the object and a pressure calculation section that calculates the pressure of the thermally conductive gas in the gap. The gas supplying line is provided with a flow rate resistive element that serves as a resistance when the thermally conductive gas flows. The pressure calculation section calculates the pressure of the thermally conductive gas in the gap based on the primary side pressure of the flow rate resistive element, the flow rate of the thermally conductive gas passing through the flow rate resistive element and the flow characteristic of the flow rate resistive element.