VCSEL Substrate Heating With In-Situ Emissivity Measurement
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Solution Overview
Problem
Accurately measuring the emissivity of flat substrates during high-temperature manufacturing processes is challenging due to factors like temperature, surface roughness, and shape, especially with the increasing demand for small temperature deviations and uniformity in semiconductor technology.
Innovation Solution
A substrate heat-treating apparatus using a laser light-emitting device with a VCSEL beam of single wavelength, which measures emissivity by irradiating and reflecting the laser beam from the substrate's surfaces without a separate light source, incorporating a beam transmitting plate, infrared transmitting plate, and an emissivity measuring module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If emissivity is measured using conventional light sources, then temperature measurement can be performed, but the measurement accuracy deteriorates due to substrate properties like temperature, surface roughness, and shape variations
Solution Approach 1:
The patent changes the wavelength parameter of the light source from conventional broadband sources to a specific single wavelength (laser wavelength) that matches the absorption characteristics of the substrate. This parameter change enables accurate emissivity measurement even under high temperature conditions and varies substrate properties, as the monochromatic light provides consistent interaction with the substrate surface.
Solution Approach 2:
The laser light source serves multiple functions: it acts as both the measurement light source for emissivity detection and as the heating source for the substrate during heat treatment. This multi-functionality eliminates the need for separate measurement and processing systems, providing universal applicability across different measurement conditions.
2Measurement precision
If a separate light source is used for emissivity measurement, then temperature measurement can be performed, but the device complexity increases
Solution Approach 1:
The patent merges the measurement light source function with the existing laser heating system. The same laser that provides thermal energy for substrate processing is also utilized for emissivity measurement by detecting the reflected or transmitted light. This combination eliminates the need for separate light sources and reduces overall device complexity while maintaining measurement precision.
Solution Approach 2:
The laser system is designed to perform dual functions: heating the substrate through absorption and measuring emissivity through light interaction. This multi-functional design reduces the number of components needed and simplifies the apparatus structure while achieving accurate temperature control through emissivity measurement.
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 allows for efficient and simplified measurement of emissivity, achieving high accuracy and temperature uniformity without additional light sources, thereby enhancing the precision and structure of the heat-treating apparatus.
Implementation Method 1
a beam irradiating module for irradiating a VCSEL beam having a single wavelength to a lower surface of the flat substrate through the beam transmitting plate
Implementation Method 2
an emissivity measuring module configured to measure the laser beam reflected from the lower surface or an upper surface the flat substrate, thereby measuring the emissivity of the flat substrate
Implementation Method 3
an infrared transmitting plate placed above the flat substrate
Data Source
AI summary
The present disclosure discloses a substrate heat-treating apparatus including a process chamber in which a flat substrate to be heat treated is placed, the process chamber comprising a beam transmitting plate placed below the flat substrate and an infrared transmitting plate placed above the flat substrate; a beam irradiating module for irradiating a VCSEL beam having a single wavelength to a lower surface of the flat substrate through the beam transmitting plate; and an emissivity measuring configured to measure the laser beam reflected from the lower surface or an upper surface the flat substrate, thereby measuring the emissivity of the flat substrate.