Rotating Wafer Carrier Plate for Uniform 800°C Heating
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Solution Overview
Problem
Existing wafer holder and temperature conditioning arrangements in vacuum processing chambers are limited in their ability to achieve high temperatures and uniform heating, which restricts the range of wafer processing techniques that can be employed.
Innovation Solution
A wafer holder and temperature conditioning arrangement that includes a metal circular wafer carrier plate directly exposed to heater lamp tubes, allowing for high-temperature heating up to at least 800°C, and featuring a rotating design with a gas cushion for enhanced heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional wafer holder with indirect heating is used, then the structure is simpler and thermal inertia is higher, but the maximum temperature achievable is limited and heating uniformity is poor
Solution Approach 1:
The heater elements (heating coils or heating plate) are extracted from the base arrangement and positioned directly adjacent to the wafer carrier plate, allowing independent optimization of the heating system while maintaining structural simplicity through modular design
Solution Approach 2:
A wafer carrier plate is introduced as an intermediary component that directly contacts the heater elements, enabling efficient heat transfer to the wafer while allowing the heater arrangement to be optimized independently from the wafer handling structure
2Manufacturing precision
If a conventional wafer holder with indirect heating is used, then the structure is simpler, but heating uniformity across the wafer surface is poor
Solution Approach 1:
Different regions of the heater arrangement are designed with different heating characteristics - heating coils positioned to provide enhanced heating at the wafer periphery while the central region receives heat from the heating plate, creating locally optimized heat distribution zones
Solution Approach 2:
The heater arrangement uses asymmetric positioning of heating elements (coils around the periphery, plate in the center) to compensate for the natural heat distribution patterns and achieve uniform temperature across the wafer surface
3Temperature
If electrostatic forces are used to hold the wafer, then no mechanical contact is needed, but heat transfer by conduction is reduced
Solution Approach 1:
The wafer carrier plate serves as a thermal intermediary that conducts heat from the heater elements to the wafer, while the wafer is retained by electrostatic forces on the opposite side, allowing thermal conduction and electrostatic retention to occur simultaneously through the plate
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 arrangement enables the processing of wafers at extremely high temperatures, facilitating the deposition of materials that require such conditions, such as lead-zirconatetitanate, while also simplifying the overall structure and reducing thermal inertia.
Implementation Method 1
heater lamp tubes arranged in the heater compartment along the extended essentially plane surface and along the one surface of the metal circular wafer carrier plate and directly exposed to this surface
Implementation Method 2
there is established, in operation, a cushion of back gas at a pressure larger than the operating vacuum pressure in processing space P, which back gas cushion improves heat transfer from the metal, circular wafer carrier plate 15 towards or from wafer 27 by heat conductions
Implementation Method 3
a wafer retaining arrangement operationally coupled to the metal circular wafer carrier plate... a weight ring 29 which, by its proper weight, biases the wafer 27 towards and upon the addressed surface 25
Data Source
AI summary
A wafer holder and temperature controlling arrangement has a metal circular wafer carrier plate, which covers a heater compartment. In the heater compartment a multitude of heater lamp tubes is arranged, which directly acts upon the circular wafer carrier plate. Latter is drivingly rotatable about the central axis. A wafer is held on the circular wafer carrier plate by means of a weight-ring residing upon the periphery of a wafer deposited on the wafer carrier plate.