Ceramic Wafer Mounting Plate Thermal Expansion Control
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Solution Overview
Problem
Conventional mounting apparatuses for temperature control of wafers face challenges in maintaining flatness and thermal conductivity, leading to increased time for temperature changes and weight due to thermal deformation and differences in thermal expansion rates between materials.
Innovation Solution
A mounting apparatus using a ceramic surface plate with a temperature control unit integrated via a heat insulation ring, where the surface plate and temperature control unit are coupled with specific bolts to maintain flatness and thermal expansion equality, and a temperature control plate ring is added to reduce external temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the top plate is made of metal with high thermal conductivity, then thermal conductivity is improved, but thermal deformation occurs due to difference in thermal expansion rate with cooling jacket, deteriorating flatness
Solution Approach 1:
The top plate is made of a composite material consisting of a metal base (copper or aluminum) with ceramic particles (alumina or silica) dispersed throughout. This composite structure combines the high thermal conductivity of metal with the low thermal expansion coefficient of ceramic, achieving both improved thermal conductivity and reduced thermal deformation to maintain flatness.
2Manufacturing precision
If the top plate is thickened to reduce influence of cooling jacket deformation, then flatness is improved, but heat capacity increases, lengthening temperature change time and increasing weight
Solution Approach 1:
By using a composite material with ceramic particles dispersed in metal matrix, the top plate achieves high stiffness and dimensional stability at reduced thickness. The ceramic particles reinforce the metal structure, providing sufficient flatness maintenance without requiring excessive thickness, thereby reducing heat capacity and temperature change time.
3Manufacturing precision
If surface processing is performed on top plate to produce flatness, then flatness is improved, but internal stress increases, and flatness deteriorates under thermal expansion difference
Solution Approach 1:
The composite material structure with ceramic particles inherently provides dimensional stability and resistance to thermal deformation. This reduces the need for aggressive surface processing to achieve and maintain flatness, thereby minimizing induced internal stresses while preserving flatness under thermal cycling conditions.
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 configuration enhances thermal conductivity, reduces temperature change time, maintains flatness, and achieves a lightweight design by minimizing thermal deformation and heat transfer inefficiencies.
Implementation Method 1
The cooling jacket 2 has therein a coolant path 2A through which a coolant flows so that the wafer can be cool down to a specific temperature by the coolant
Implementation Method 2
The plate heater 3 heats the wafer to a specific temperature through the cooling jacket 2 and the top plate 1
Implementation Method 3
the temperature control unit 4 and the heat insulation plate 6 are spaced apart from each other by the heat insulation ring 5, thereby being heat-insulated from each other
Data Source
AI summary
A mounting apparatus includes a surface plate; a temperature control unit integrated with the surface plate; and a bottom plate integrated with the temperature control unit via a heat insulation ring, wherein a temperature of a target object held on the surface plate is capable of being controlled and the surface plate is formed of ceramic. The surface plate and the temperature control unit are coupled to each other by a first coupling member at each portion thereof except for each peripheral portion thereof such that the peripheral portion of the surface plate being not coupled thereto. The peripheral portion of the temperature control unit is coupled to the heat insulation ring by a second coupling member.