Substrate Edge Infrared Temperature Measurement Below 400°C

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Solution Overview

Problem

Existing methods for measuring substrate temperatures in semiconductor manufacturing, particularly at low temperatures below 400°C, are inaccurate due to the transparency of substrates to infrared wavelengths and the limitations of physical contact methods like thermocouples.

Innovation Solution

The use of infrared cameras to measure the temperature of a substrate's edge surface, rather than its top surface, which allows for non-contact, accurate temperature profiling across all types of substrates, including blank substrates, and enables measurements below 400°C.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermocouples are used to measure substrate temperature by physical contact, then temperature measurement is possible, but measurement precision deteriorates due to contamination concerns and unreliable thermal physical contact

Engineering Contradiction:

Improvereliability of thermal physical contactVSAvoidsubstrate temperature measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical contact system (thermocouple physically touching the substrate) with a non-contact optical system (infrared camera). The infrared camera measures substrate temperature by detecting infrared radiation emitted from the substrate surface, eliminating the need for physical contact and associated contamination and reliability issues.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If thermocouples are placed at predetermined locations on substrate surface, then temperature measurement is possible, but measurement precision deteriorates due to large distances between measurement locations on larger diameter substrates

Engineering Contradiction:

Improveoverall temperature variation measurementVSAvoidnumber of measurement locations required

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The infrared camera captures a two-dimensional image of the substrate surface, allowing temperature measurement across the entire substrate area simultaneously. This eliminates the need for multiple discrete thermocouple placements and provides comprehensive temperature variation data across the substrate surface in a single measurement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If infrared camera views top surface of blank substrate, then non-contact measurement is possible, but measurement precision deteriorates because substrate is transparent to infrared wavelengths at temperatures under 400°C

Engineering Contradiction:

Improvelow temperature measurement capabilityVSAvoidsubstrate transparency to infrared wavelengths

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the measurement dimension from viewing the top surface (where transparency causes problems) to viewing the edge surface (where the substrate is opaque). By measuring the edge surface, the infrared camera can detect infrared radiation without the substrate material interfering, enabling accurate low temperature measurements.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Measurement precision

If scanning monochrometer with filters is used to measure reflected infrared energy, then temperature measurement is possible, but device complexity increases and measurement speed decreases

Engineering Contradiction:

Improvetemperature measurement accuracyVSAvoidbulkiness and cost of monochrometer system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the temperature measurement function from the complex scanning monochrometer system and implements it using a simpler infrared camera. The infrared camera directly captures infrared radiation from the substrate edge surface, eliminating the need for mechanical filter rotation and complex wavelength scanning while maintaining measurement capability.

Inventive Principle:

Principle #2Taking out (Extraction)

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 method provides a reliable and accurate means of measuring substrate temperatures, improving process control in semiconductor manufacturing by ensuring precise temperature measurements across various substrate types and temperatures.

Implementation Method 1

measuring the infrared (IR) energy emitted from the surface of a heated substrate

Methodology Applied

Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 2

measuring the infrared (IR) energy emitted from the surface of a heated substrate, then converting this measured energy into a temperature reading

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentUS12230521B2Method for non-contact low substrate temperature measurement

Publication Date: 2025.02.18 APPLIED MATERIALS INC

AI summary

A method and apparatus for measuring a temperature of a substrate located in a semiconductor processing environment is disclosed. The substrate has a top surface and an edge surface, and is positioned in a prescribed location within the semiconductor processing environment. An infrared camera oriented to view one side of the edge surface of the substrate is triggered to obtain an infrared image of the one side of the edge surface of the substrate. The infrared image is processed to obtain a temperature profile of the substrate.