Substrate Temperature Measurement Using Dual Pyrometers
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Solution Overview
Problem
Existing heat treatment apparatuses struggle to accurately measure substrate temperatures below 500°C due to radiant energy passing through the substrate, leading to measurement errors and inability to perform rapid low-temperature processes.
Innovation Solution
A substrate treatment apparatus with a process chamber, heating housing, and pyrometers that measure wavelengths greater than 4 μm, allowing for accurate temperature calculation by compensating for window measurement energy in substrate measurement energy, enabling precise temperature control of heating lamps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If pyrometers measure temperature in the wavelength range of 0.9 μm to 1.1 μm, then temperature measurement is possible at high temperatures (450°C to 1250°C), but measurement accuracy deteriorates at low temperatures (below 500°C) due to substrate light transmission
Solution Approach 1:
The patent changes the measurement wavelength parameter from 0.9-1.1 μm to greater than 4 μm. This parameter change exploits the fact that silicon substrate transmittance characteristics differ at different wavelengths, particularly that at wavelengths greater than 4 μm, the substrate becomes more opaque, eliminating the light transmission interference that causes measurement errors at low temperatures.
Solution Approach 2:
The patent uses a reference measurement approach where the pyrometer first measures the window's radiant energy independently, then uses this reference data to compensate for the window's contribution when measuring substrate temperature. This copying of the measurement process allows separation of window and substrate signals.
2Use of energy by moving object
If heating lamps transmit radiant energy through the substrate at low temperatures, then heating efficiency is maintained, but temperature measurement accuracy deteriorates due to additive measurement of substrate and transmitted light wavelengths
Solution Approach 1:
The patent introduces a reference measurement of the window's radiant energy as an intermediary step. By measuring the window's energy independently and then compensating it from the substrate measurement, the system separates the overlapping signals. This intermediary measurement allows the system to maintain heating efficiency while achieving accurate temperature measurement.
Solution Approach 2:
The patent extracts and removes the window's radiant energy contribution from the total measured energy. By measuring the window's energy separately and subtracting it from the combined measurement, the system isolates the substrate's thermal radiation signal, eliminating the measurement error caused by transmitted heating lamp light.
3Measurement precision
If pyrometers use long-wavelength range (5 μm to 15 μm) for measurement, then low-temperature measurement capability is improved, but device complexity increases due to additional compensation mechanisms
Solution Approach 1:
The patent makes the pyrometer system multi-functional by enabling it to perform both window energy measurement and substrate temperature measurement using the same device. The pyrometer can operate in different measurement modes (measuring window independently, then measuring substrate through the window), eliminating the need for separate measurement devices and reducing overall system complexity.
Solution Approach 2:
The system performs self-calibration and self-compensation by using its own pyrometer to measure both the window's radiant energy and the substrate's temperature. The measured window energy is automatically used to compensate the substrate measurement, making the system self-sufficient without requiring external calibration equipment or additional complex compensation mechanisms.
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
Enables accurate temperature measurement and control of substrates at low temperatures, enhancing the competitiveness of device manufacturing by allowing for various substrate treatment processes regardless of temperature.
Implementation Method 1
calculate the temperature of the substrate in a non-contact manner on the basis of the relation between black body radiation and temperature
Implementation Method 2
heating lamps for generating radiant energy
Data Source
AI summary
The present invention relates to a substrate treatment apparatus and method which perform heat treatment on a substrate, and can accurately measure the temperature of the substrate even at a low temperature. An embodiment of the present invention includes a process chamber that has a substrate treatment space, a heating housing that contains a plurality of heating lamps for generating radiant energy, a window that is placed between the heating housing and the process chamber to maintain the air-tightness of the process chamber and transmit the radiant energy to be transferred to a substrate, a first pyrometer that measures a wavelength generated at the substrate in the process chamber, and converts the wavelength into substrate measurement energy, a second pyrometer that measures a wavelength generated at the window, and converts the wavelength into window measurement energy; and a heating controller that compensates for the window measurement energy in the substrate measurement energy, thereby calculating the temperature of the substrate itself, and uses the calculated temperature of the substrate itself to control the heating lamps.