Optical Pyrometer Substrate Temperature Calibration

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing substrate temperature measurement techniques in high-temperature processing face challenges such as thermal conduction offsets in vacuum environments, damage from contact measurements, and complexity in controlling thermocouple contact force, leading to inaccurate temperature control and increased system complexity.

Innovation Solution

A method employing a non-contact optical pyrometer to measure substrate temperature, calibrated using a Thermocouple (TC) embedded in a remote process station, which generates a voltage decay curve to determine the substrate temperature without requiring a TC in the preheat station, allowing for accurate temperature measurement and control across different wafer types with varying emissivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a contact temperature measurement approach (thermocouple) is used to measure substrate temperature in a preheat chamber, then temperature measurement can be performed, but thermal conduction offsets occur in vacuum environments leading to inaccurate temperature measurement

Engineering Contradiction:

Improvesubstrate temperature measurement accuracyVSAvoidtemperature measurement reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical contact thermocouple measurement system with a non-contact optical pyrometer system. The pyrometer measures substrate temperature by detecting thermal radiation from the substrate surface without physical contact, thereby eliminating thermal conduction offsets caused by vacuum gaps and contact pressure variations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a thermocouple contact approach is used to measure substrate temperature, then temperature can be measured, but the contact approach requires additional mechanisms to control contact force increasing system complexity

Engineering Contradiction:

Improvesubstrate temperature measurementVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent eliminates the mechanical contact system entirely by using an optical pyrometer for non-contact temperature measurement. This removes the need for motors, contact force control mechanisms, and associated complexity while achieving accurate temperature measurement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If a thermocouple is pressed into the wafer surface during calibration, then temperature measurement is achieved, but microscopic scratching of the wafer surface occurs causing particle contamination

Engineering Contradiction:

Improvetemperature calibrationVSAvoidsubstrate damage and contamination

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent uses non-contact optical pyrometer measurement for temperature calibration, completely avoiding mechanical contact with the wafer surface. This eliminates microscopic scratching and particle contamination while maintaining calibration accuracy through optical detection of thermal radiation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If a heavier thermocouple is used for temperature measurement, then more stable and accurate temperature measurement is achieved, but the response time becomes slower reducing overall throughput

Engineering Contradiction:

Improvetemperature measurement stabilityVSAvoidmachine throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the thermal mass-dependent thermocouple system with an optical pyrometer system that measures temperature based on thermal radiation. This eliminates the trade-off between thermocouple mass, stability, and response time, achieving fast response and stable measurement simultaneously through non-contact optical detection.

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 approach provides accurate and repeatable substrate temperature measurement in a preheat station without damaging the substrate, reducing system complexity and enabling periodic health checks, ensuring consistent preheat temperatures for improved process control and throughput.

Implementation Method 1

measuring a voltage decay after transferring the substrate to the second chamber, using an optical pyrometer to measure pyrometer voltage as a function of time

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

substrate temperature measurement may be performed by a contact approach, such as using a thermocouple (TC) to directly measure heat (TC contact approach) conducted from the substrate or platen to the thermocouple

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11543296B2Method and apparatus for calibration of substrate temperature using pyrometer

Publication Date: 2023.01.03 APPLIED MATERIALS INC

AI summary

A method may include heating a substrate in a first chamber to a platen temperature, the heating comprising heating the substrate on a platen; measuring the platen temperature in the first chamber using a contact temperature measurement; transferring the substrate to a second chamber after the heating; and measuring a voltage decay after transferring the substrate to the second chamber, using an optical pyrometer to measure pyrometer voltage as a function of time.