Substrate Temperature Uniformity via Optical Correction
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Solution Overview
Problem
Conventional rapid thermal processing (RTP) apparatuses face challenges in achieving uniform temperature distribution across semiconductor wafers due to the need for rotation, which complicates the apparatus configuration, generates particles, and makes it difficult to detect local non-uniformities, potentially leading to warping and temperature abnormalities, especially in back side annealing processes.
Innovation Solution
A heat treatment apparatus that uses a quartz window for light irradiation and an infrared-transparent window made of silicon or sapphire to detect and correct temperature non-uniformities without rotating the substrate, allowing two-dimensional temperature detection and correction of temperature drop regions using a laser light emission part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a wafer rotation mechanism is provided in the chamber to achieve uniform temperature distribution, then temperature uniformity is improved, but device complexity and chamber size increase
Solution Approach 1:
The patent replaces the mechanical wafer rotation system with a stationary illumination system that uses multiple light sources arranged in concentric circles. The optical system projects light patterns that create uniform thermal distribution across the wafer surface without requiring mechanical movement, thereby eliminating rotation mechanism complexity while achieving temperature uniformity.
Solution Approach 2:
The patent transitions from a one-dimensional rotation-based approach to a two-dimensional spatial distribution of light sources. By arranging illumination sources in concentric circular patterns and controlling their individual outputs, the system achieves uniform temperature distribution through spatial optimization rather than mechanical rotation.
2Temperature
If a wafer rotation mechanism is provided to achieve uniform temperature distribution, then temperature uniformity is improved, but particle generation increases
Solution Approach 1:
The patent eliminates the mechanical rotation system that generates particles through friction and wear. Instead, it uses a stationary optical-thermal system where light sources and a stationary wafer create no mechanical contact or movement, thereby preventing particle generation while maintaining temperature uniformity through optical field distribution.
3Adaptability or versatility
If the substrate is supported at the peripheral portion for back side annealing, then light access to the back surface is enabled, but temperature abnormality and warping occur in the peripheral portion
Solution Approach 1:
The patent applies local quality control by providing independent temperature control for different zones of the wafer. The peripheral region, which experiences support-induced cooling, receives enhanced or adjusted illumination to compensate for the temperature drop, ensuring uniform temperature distribution across the entire wafer surface while maintaining back side annealing capability.
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 approach enables uniform temperature distribution across the entire substrate surface without rotation, simplifying the apparatus configuration, reducing particle generation, and allowing for precise detection and correction of local non-uniformities, thereby enhancing processing accuracy and throughput.
Implementation Method 1
a halogen lamp configured to irradiate one side of the substrate held on the holding part with light through the quartz window
Implementation Method 2
a temperature detection part configured to receive an infrared ray emitted from the other side of the substrate held on the holding part
Implementation Method 3
a temperature detection part configured to receive an infrared ray emitted from the other side of the substrate
Implementation Method 4
an infrared-transparent window arranged at the other end of the chamber and configured to allow an infrared ray in a wavelength region detectable by the temperature detection part to transmit therethrough
Implementation Method 5
a temperature correction part configured to, based on a result of the detection obtained by the temperature detection part, heat a temperature drop region
Data Source
AI summary
The temperature of a semiconductor wafer is raised by light irradiation heating performed by halogen lamps. An infrared ray emitted from the semiconductor wafer whose temperature has been raised transmits through an infrared-transparent window made of silicon, and then is detected by an infrared camera. The infrared camera two-dimensionally detects the temperature of an entire surface of the semiconductor wafer. Based on a result of the detection obtained by the infrared camera, a temperature drop region having a relatively low temperature among the region of the semiconductor wafer is irradiated with laser light emitted from a laser light emission part. Accordingly, without rotating the semiconductor wafer, a temperature distribution can be made uniform with a high accuracy throughout the entire surface of the semiconductor wafer.