Wafer Support Table Thermal Uniformity
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Solution Overview
Problem
Ceramic wafer support tables used in plasma CVD processes face issues with thermal uniformity at the outer peripheral parts due to heat extraction from the shaft, leading to decreased temperature consistency.
Innovation Solution
A wafer support table design featuring a ceramic base with multiple heaters, including a central first heater, peripheral second heaters, and radially divided third heaters, allowing individual temperature control and improved thermal uniformity by embedding the first heater closer to the wafer placement surface, thus minimizing jumper wire interference and enhancing design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multilayer heaters are used to prevent temperature decrease at the central part, then temperature stability at the center is improved, but thermal uniformity deteriorates due to peripheral heat extraction influences
Solution Approach 1:
The heater system is divided into three distinct layers (first, second, and third heaters) with different configurations and control strategies. The first heater is segmented into multiple independently controllable zones, allowing differential temperature control to compensate for peripheral heat loss while maintaining central temperature stability.
Solution Approach 2:
Different regions of the wafer support table are provided with different heater configurations and control characteristics. The first heater uses multiple independently controlled heating zones with different power levels to address local thermal variations, particularly compensating for greater heat loss at peripheral regions compared to the center.
2Adaptability or versatility
If first heater is embedded closer to the wafer placement surface, then design flexibility increases and jumper wire interference is reduced, but manufacturing complexity increases
Solution Approach 1:
The first heater is positioned in a different depth dimension compared to conventional designs, embedding it closer to the wafer placement surface rather than at the rear surface. This dimensional repositioning allows jumper wires to be routed on the rear surface without passing through the heater structure, eliminating interference while maintaining electrical isolation.
Solution Approach 2:
The ceramic base structure serves as an intermediary medium that accommodates the repositioned first heater closer to the wafer surface. The ceramic material provides both structural support and electrical insulation, enabling the heater to be positioned in this intermediate location without compromising safety or functionality.
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 design enhances thermal uniformity and design flexibility by allowing precise temperature control and reducing the influence of peripheral factors, while simplifying manufacturing and reducing jumper-induced heating effects.
Implementation Method 1
a plurality of heaters embedded in the ceramic base
Data Source
AI summary
A wafer support table includes a ceramic base having a wafer placement surface, and a plurality of heaters embedded in the ceramic base. The ceramic base has a first heater formation surface, a second heater formation surface, and a third heater formation surface in a stated order from the wafer placement surface toward a surface opposite from the wafer placement surface. A first heater is provided on the first heater formation surface so as to be located at a center of the ceramic base. A second heater is provided on the second heater formation surface so as to be located around a periphery of the first heater. A third heater is provided on the third heater formation surface so as to overlap the second heater and is provided in each of a plurality of zones divided from the third heater formation surface by a radial line segment.