Substrate Heat Treatment Apparatus Thermal Stress Reduction
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Solution Overview
Problem
Conventional substrate heat treatment apparatuses face issues with thermal expansion and heat loss due to the difference in thermal expansion coefficients between ceramic guard rings and metallic lifting devices, leading to potential breakage and uneven temperature distribution during high-temperature processes.
Innovation Solution
A substrate heat treatment apparatus with a substrate supporting plate, a lifting mechanism, and a linking member having lower thermal conductivity than the supporting plate, which allows for independent movement of the supporting plate between heating and non-heating positions, reducing thermal stress and heat transfer between components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a guard ring is provided around the wafer to improve temperature uniformity, then temperature uniformity is improved, but the mechanism becomes complicated and reliability decreases due to additional lifting device requirements
Solution Approach 1:
The guard ring is integrated with the wafer support plate, forming a unified structure that eliminates the need for separate lifting mechanisms. The support plate with integrated guard ring is lifted as a single unit by the existing lifting device, simplifying the overall mechanism while maintaining temperature uniformity functionality.
Solution Approach 2:
The support plate serves multiple functions: it supports the wafer, provides the guard ring for temperature uniformity, and is lifted by the lifting device. This multi-functional design eliminates the need for dedicated guard ring lifting mechanisms, reducing complexity and improving reliability.
2Stability of the object's composition
If the guard ring is rigidly connected to the lifting device for stable support, then structural stability is improved, but thermal stress increases due to different thermal expansion coefficients causing potential breakage
Solution Approach 1:
A flexible connection structure is used between the support plate and lifting device, allowing thermal expansion and contraction without rigid constraints. This flexible linkage accommodates differential thermal expansion between ceramic and metal components, reducing thermal stress while maintaining structural stability.
Solution Approach 2:
The connection structure is designed to change its mechanical properties with temperature, becoming more compliant at high temperatures to accommodate thermal expansion differences. This parameter change allows the system to maintain stability across temperature ranges while reducing thermal stress on components.
3Productivity
If the support plate is heated to high temperature for fast heating, then heating speed is improved, but heat loss increases due to thermal conduction through the lifting mechanism
Solution Approach 1:
A thermal insulation layer is introduced as an intermediary between the heated support plate and the lifting device. This insulation barrier reduces thermal conduction to the cooler lifting mechanism, minimizing heat loss while allowing the support plate to reach high temperatures for fast heating.
Solution Approach 2:
A thin thermal insulation film or layer is applied to the support plate, providing thermal barrier functionality. This thin film reduces heat conduction to the lifting device while maintaining the high temperature capability of the support plate for fast heating operations.
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 alleviates thermal expansion issues and minimizes heat loss, enabling uniform high-speed heating of substrates while reducing the risk of component damage and maintaining even temperature distribution.
Implementation Method 1
a linking member linking the substrate supporting plate and the lifting mechanism, the linking member having lower thermal conductivity than that of the substrate supporting plate
Implementation Method 2
a heating means for heating the substrate supported by the substrate supporting plate from above the substrate supporting plate in the gravity direction
Implementation Method 3
the difference in thermal expansion coefficients between ceramic guard rings and metallic lifting devices, leading to potential breakage
Data Source
AI summary
The present invention provides a substrate heat treatment apparatus capable of uniformly heat a substrate at high speed with less breakage of constituent members due to thermal expansion even at high temperature. An embodiment of the present invention is a substrate heat treatment apparatus to perform heat treatment for a substrate and includes: a peripheral ring capable of supporting the substrate; a connection ring; a lifting device to raise and lower the peripheral ring; balls having a lower heat conductivity than that of the peripheral ring; and a lamp to heat the substrate supported by the peripheral ring. The balls are different members from both of the peripheral ring and the connection ring. The lifting device raises and lowers the peripheral ring between a first position close to the lamp and a second position distant from the lamp.