Semiconductor Wafer Temperature Sensing Under Emissivity Variation

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Solution Overview

Problem

Existing temperature measurement methods for semiconductor wafers during flash lamp annealing are inaccurate due to variations in emissivity caused by changes in infrared transmittance and stacking of thin films, which complicates precise temperature control for activating impurities without deep diffusion.

Innovation Solution

A method and apparatus that utilize oblique detection of brightness temperature to calculate input parameters related to emissivity ratio and substrate temperature, enabling accurate temperature estimation through multiple input parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a predetermined emissivity is set for temperature measurement, then the measurement process is simple, but the temperature measurement accuracy deteriorates due to emissivity variations from infrared transmittance changes and thin film stacking

Engineering Contradiction:

Improvetemperature measurement process simplicityVSAvoidtemperature measurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the measurement parameter from direct temperature measurement to brightness temperature measurement. By measuring brightness temperature at multiple wavelengths and using the ratio of Planck's law values at different wavelengths, the system eliminates the need to know the absolute emissivity value, thus resolving the contradiction between measurement simplicity and accuracy

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces brightness temperature as an intermediary parameter. Instead of directly measuring temperature which requires knowing emissivity, the system first measures brightness temperature (which can be done without knowing emissivity) and then converts it to actual temperature using the brightness temperature and the measured or estimated emissivity ratio

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If conventional radiation thermometers are used with predetermined emissivity, then the device complexity is low, but the temperature control precision for activating impurities without deep diffusion deteriorates

Engineering Contradiction:

Improvetemperature measurement device complexityVSAvoidtemperature control precision for impurity activation

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent segments the temperature measurement process into multiple wavelength measurements. By measuring brightness temperature at multiple discrete wavelengths and analyzing the ratio relationships, the system achieves precise temperature control without requiring complex single-wavelength measurements or prior knowledge of absolute emissivity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent makes the measurement system universal by eliminating the need for emissivity calibration specific to each wafer condition. The multi-wavelength brightness temperature ratio method works universally across different thin film stackings and infrared transmittance conditions, providing consistent temperature control precision without requiring device reconfiguration

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Accurately measures the temperature of semiconductor wafers by accounting for emissivity variations, ensuring precise temperature control for activating impurities while preventing deep diffusion.

Implementation Method 1

detecting at least one brightness temperature of a semiconductor wafer W

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

the wavelength of light emitted from the xenon flash lamps is shorter than that of light emitted from conventional halogen lamps, and approximately coincides with a fundamental absorption band of a silicon semiconductor wafer. Thus, when a semiconductor wafer is irradiated with a flash of light emitted from the xenon flash lamps, the temperature of the semiconductor wafer can be raised rapidly

Methodology Applied

Scientific EffectOptical absorption: Absorption (EM radiation)

Data Source

PatentUS12550665B2Temperature measurement method and heat treatment apparatus

Publication Date: 2026.02.10 SCREEN HOLDINGS CO LTD

AI summary

A temperature measurement method includes: a radiation temperature measurement step for detecting a brightness temperature of a semiconductor wafer from obliquely below the semiconductor wafer; an input parameter calculation step for calculating at least two input parameters from the brightness temperature detected in the radiation temperature measurement step, the at least two input parameters including a first input parameter corresponding to an emissivity ratio of the semiconductor wafer and a second input parameter corresponding to a temperature of the semiconductor wafer; an output parameter estimation step for estimating an output parameter from the first input parameter and the second input parameter; and a temperature calculation step for calculating the temperature of the semiconductor wafer from the output parameter estimated in the output parameter estimation step and the brightness temperature detected in the radiation temperature measurement step.