Infrared Transmission Window for Non-Contact Wafer Temperature Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing substrate processing technologies face challenges in accurately measuring the temperature of wafers within a chamber from outside, especially when using an LED light source as a heat source, due to the pressure-reduced atmosphere and the need for non-contact measurement.
Innovation Solution
A substrate processing apparatus is designed with a heat ray sensor and an infrared ray transmission window that allows for non-contact temperature measurement by receiving infrared rays with wavelengths greater than or equal to 8 μm, using a thermopile and diamond window to accurately calculate the wafer temperature despite noise from the heat source and chamber components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If non-contact temperature measurement is performed from outside the chamber, then measurement accessibility is improved, but measurement precision deteriorates due to interference from chamber components and pressure-reduced atmosphere
Solution Approach 1:
An infrared transmission window is introduced as an intermediary component between the substrate inside the chamber and the heat ray sensor outside. This window selectively transmits infrared rays with wavelengths of 8 μm or more while blocking other wavelengths, enabling accurate non-contact temperature measurement by allowing the desired thermal radiation to pass through while filtering out interfering radiation from chamber components.
Solution Approach 2:
The invention changes the wavelength parameter of infrared radiation being measured by selecting and transmitting only wavelengths of 8 μm or more. This parameter selection allows the system to measure substrate temperature accurately by focusing on the thermal radiation band that is least affected by interference from the LED light source and chamber components, while still being emitted by the heated substrate.
2Use of energy by moving object
If LED light source is used for heating, then energy efficiency is improved, but temperature measurement accuracy deteriorates due to noise from the light source and chamber components
Solution Approach 1:
The infrared transmission window acts as a spectral filter that distinguishes between the heating radiation from the LED light source and the thermal radiation from the heated substrate. By transmitting only infrared rays with wavelengths of 8 μm or more, it blocks the shorter wavelength radiation from the LED while allowing the longer wavelength thermal radiation from the substrate to reach the sensor, thereby eliminating measurement noise.
Solution Approach 2:
The invention changes the wavelength parameter of the detected radiation to 8 μm or more, which corresponds to the thermal radiation emitted by the substrate at heating temperatures. This parameter change effectively filters out the LED light source noise while capturing the substrate temperature signal, enabling accurate measurement despite the presence of the LED heating source.
3Productivity
If heating time is reduced for improved productivity, then processing speed is improved, but temperature control accuracy deteriorates
Solution Approach 1:
The invention implements a feedback control system where the heat ray sensor continuously measures the substrate temperature through the infrared transmission window, and the LED light source controller adjusts the heating power based on this real-time temperature information. This feedback mechanism enables accurate temperature control even during rapid heating processes, maintaining processing quality while improving throughput by reducing heating time.
Solution Approach 2:
The invention replaces contact-based temperature measurement methods with non-contact infrared measurement. This substitution allows for rapid, real-time temperature monitoring without physical contact, enabling faster heating cycles while maintaining precise temperature control through continuous feedback from the heat ray sensor.
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 enables precise temperature measurement and feedback control of the LED light source, significantly reducing heating time and improving processing throughput by accurately measuring temperatures within the desired range of room temperature to 300 degrees C.
Implementation Method 1
a heat ray sensor provided outside the chamber and configured to receive infrared rays radiated from the substrate
Implementation Method 2
an infrared ray transmission window provided in the chamber and configured to transmit an infrared ray having a wavelength greater than or equal to 8 μm to the heat ray sensor
Implementation Method 3
a heat source configured to heat-treat the substrate
Data Source
AI summary
The present disclosure is a substrate processing apparatus including: a chamber configured to accommodate a substrate; a heat source configured to heat-treat the substrate; a heat ray sensor provided outside the chamber and configured to receive infrared rays radiated from the substrate; and an infrared ray transmission window provided in the chamber and configured to transmit an infrared ray having a wavelength greater than or equal to 8 μm to the heat ray sensor.