Variable Thickness Substrate Carrier for VPE Temperature Uniformity
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Solution Overview
Problem
Current material processing systems, particularly vapor phase epitaxy (VPE) systems, face challenges in achieving uniform temperature control and high yield during substrate processing, leading to variations in emission wavelength and material properties, which are critical for manufacturing high-quality LED and semiconductor laser devices.
Innovation Solution
The method involves modifying substrate carriers to achieve precise temperature uniformity or profiles by adjusting the step height and thermal conductivity of the carrier, using post-growth measurement and analysis to compensate for non-uniformities, and employing a hybrid conduction-convection heat transfer model to optimize heat transfer mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the substrate carrier uses a simple flat design, then the device complexity is low, but the temperature uniformity across the substrate is poor
Solution Approach 1:
The substrate carrier incorporates variable thickness regions where different areas have different thicknesses to provide localized thermal compensation. Thinner regions provide less thermal mass and conduct heat differently compared to thicker regions, enabling precise control of temperature distribution across the substrate surface without requiring a completely complex carrier structure
Solution Approach 2:
The carrier is divided into multiple functional zones with different thickness characteristics - central regions, edge regions, and intermediate zones - each optimized for specific thermal management requirements. This segmentation allows independent optimization of temperature control in different areas while maintaining overall structural simplicity
2Reliability
If the substrate carrier thickness is increased to improve thermal conductivity, then heat transfer improves, but the temperature control precision deteriorates due to excessive thermal mass
Solution Approach 1:
Different regions of the substrate carrier have different thicknesses optimized for their specific functional requirements. Central regions may have different thickness compared to edge regions, allowing each area to provide appropriate thermal characteristics - sufficient thermal mass for stability where needed, and reduced thermal mass for precision control where required
Solution Approach 2:
The thickness parameter of the substrate carrier is varied continuously or discretely across different regions to optimize the balance between thermal conductivity and thermal mass. By changing this geometric parameter locally, the system achieves both process stability and emission wavelength precision without requiring excessive overall thickness
3Temperature
If variable thickness regions are added to the substrate carrier, then temperature uniformity improves, but the manufacturing complexity increases
Solution Approach 1:
The variable thickness design is implemented through localized modifications rather than complete structural redesign. Specific regions are thinned or thickened using standard manufacturing techniques, maintaining overall fabrication simplicity while achieving the desired temperature uniformity through localized geometric variations
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 enhances process performance by ensuring uniform temperature distribution across the substrate, improving the yield and stability of emission wavelengths, thereby producing high-quality semiconductor devices with precise optical properties.
Implementation Method 1
employing a hybrid conduction-convection heat transfer model to optimize heat transfer mechanisms
Implementation Method 2
Vapor phase epitaxy is a type of chemical vapor deposition (CVD) which involves directing one or more gases containing chemical species onto a surface of a substrate
Data Source
AI summary
A method of modifying a substrate carrier to improve process performance includes depositing material or fabricating devices on a substrate supported by a substrate carrier. A parameter of layers deposited on the substrate is then measured as a function of their corresponding positions on the substrate carrier. The measured parameter of at least some devices fabricated on the substrate or a property of the deposited layers is related to a physical characteristic of substrate carrier to obtain a plurality of physical characteristics of the substrate carrier corresponding to a plurality of positions on the substrate carrier. The physical characteristic of the substrate carrier is then modified at one or more of the plurality of corresponding positions on the substrate carrier to obtain desired parameters of the deposited layers or fabricated devices as a function of position on the substrate carrier.