Composite Substrate Heating Plate for Uniform Thermal Distribution
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Solution Overview
Problem
Conventional substrate heating units face issues with thermal deformation, non-uniform heat distribution, and increased weight and volume due to the use of single-material plates, which can damage substrates and hinder precise temperature control in semiconductor manufacturing processes.
Innovation Solution
A substrate heating unit with an upper plate of varying thickness in the radial direction and a lower plate with a corresponding shape, featuring different materials for enhanced thermal conductivity and reduced thermal expansion, along with vacuum holes for controlled pressure and a heat generating member for uniform heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the plate is made thin to reduce weight and volume, then the weight and volume decrease, but thermal deformation occurs under high temperature
Solution Approach 1:
The plate is constructed as a composite structure combining a metal plate (for thermal conductivity) with a ceramic coating layer (for low thermal expansion and high temperature stability). This composite material approach allows the plate to remain thin while preventing thermal deformation through the ceramic layer's low expansion coefficient, resolving the contradiction between reduced weight/volume and thermal stability.
2Reliability
If the plate is made thick to prevent thermal deformation, then thermal stability improves, but weight and volume increase
Solution Approach 1:
Instead of increasing the overall plate thickness, a thin ceramic coating layer is applied on the metal plate surface. This ceramic layer provides thermal deformation prevention without significantly increasing weight or volume, as it is much thinner than a solid ceramic plate would be, while still delivering the necessary thermal stability.
Solution Approach 2:
The ceramic coating is applied specifically on the plate surface where thermal deformation occurs, rather than making the entire plate thick. This localized application of ceramic material provides thermal stability exactly where needed (at the heated surface) without unnecessarily increasing the overall plate thickness, weight, and volume throughout the entire structure.
3Temperature
If heat is generated from the resistance heat generating member, then heating function is provided, but heat loss occurs at the plate edge to the circumferential surface
Solution Approach 1:
The plate undergoes controlled thermal expansion due to heating, and the ceramic coating layer, with its low thermal expansion coefficient, creates compressive stress on the metal plate surface. This stress distribution change modifies the thermal field, reducing heat loss at the edges and improving overall heat utilization efficiency.
Solution Approach 2:
The differential thermal expansion between the metal plate and ceramic coating layer is utilized to control heat distribution. The ceramic layer's low expansion coefficient creates a stress state that reduces thermal energy loss at the plate edges, thereby improving heating efficiency and reducing energy waste.
4Temperature
If heat is transferred through the plate, then substrate heating is achieved, but non-uniform temperature distribution occurs between edge and center
Solution Approach 1:
The thermal expansion of the metal plate and the constrained expansion of the ceramic coating layer create a stress distribution that modifies heat flow paths. This stress-induced heat distribution uniformity ensures that heat is more evenly distributed from center to edge, achieving uniform substrate temperature and improving manufacturing precision.
Solution Approach 2:
The metal-ceramic composite plate structure creates a controlled thermal field through the interaction of different material properties. The ceramic layer's thermal characteristics combined with the metal plate's conductivity produce a more uniform heat distribution across the substrate surface, eliminating the non-uniform temperature gradient between edge and center.
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
The solution prevents substrate damage from thermal deformation, ensures uniform heating across the entire substrate surface, reduces weight and volume, and maintains precise temperature control, enhancing the efficiency of semiconductor manufacturing processes.
Implementation Method 1
a resistance heat generating member made of a composite material of metal particles and glass and attached on a rear surface of the plate
Implementation Method 2
the upper surface of the upper plate may be formed with a plurality of first vacuum holes in a radial direction thereof, the pressure of the first vacuum holes is controlled individually or as a group such that the pressure inside the first vacuum holes is changed according to the region of the substrate
Data Source
AI summary
Provided are a substrate heating unit heating a substrate, and a substrate treating apparatus including the same. The substrate heating unit heats the substrate by transferring heat generated from a resistance heat generating member to a supporting plate. The supporting plate includes an upper plate having a central region which is thicker than an edge region thereof, and a lower plate made of a material having a thermal conductivity lower than the material of the upper plate. By a difference in the shape and material of the upper plate and lower plate, heat arrives at the substrate more rapidly in the edge region than in the central region, so that an entire surface of the substrate is heated uniformly.