Ceramic Heater Electrode Thickness Variation for Uniform Wafer Heating
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Solution Overview
Problem
Existing electrostatic chuck heaters face challenges in uniformly heating wafers due to limitations in reducing the width and line interval of heater electrodes, which can lead to disconnection, short circuits, and difficulties in improving heat generation and soaking performance around specific temperature areas.
Innovation Solution
A ceramic heater design with a heater electrode having a smaller thickness and larger resistance in specific areas surrounding low-temperature regions, allowing for increased heat generation and facilitating soaking design by maintaining the same width as normal portions, while using multiple resistance heating line portions to locally generate more heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the width of the heater electrode is reduced around the specific temperature area, then the amount of heat generation is increased, but the reliability of the heater electrode is reduced due to disconnection risk
Solution Approach 1:
The heater electrode is designed with different thicknesses in different regions: a first thickness in the normal area and a second, smaller thickness in the specific area surrounding the low-temperature region. This local variation in thickness allows the specific area to generate more heat per unit length while the normal area maintains sufficient thickness for reliability, thus resolving the contradiction between heat generation and connection reliability.
2Power
If the line interval of the heater electrode is reduced around the specific temperature area, then the amount of heat generation is increased, but the risk of short circuit is increased
Solution Approach 1:
Instead of reducing the line interval which would increase short circuit risk, the invention reduces the thickness of the heater electrode in the specific area. This approach increases heat generation in the target region while maintaining adequate spacing between adjacent heater electrode lines, thereby avoiding short circuit risks while achieving the desired heating effect.
3Power
If the number of regions with reduced width or line interval is increased, then the heat generation in specific areas is improved, but the soaking performance across the entire plate deteriorates
Solution Approach 1:
The invention applies thickness reduction to a specifically defined area surrounding the low-temperature region, rather than reducing width or line interval across multiple regions. This localized approach concentrates the heat generation enhancement where it is most needed while preserving the overall soaking performance across the entire plate, thus resolving the contradiction between specific area heating and global uniformity.
Solution Approach 2:
The invention changes the thickness parameter of the heater electrode in the specific area rather than changing the width or line interval parameters. This parameter substitution allows for increased heat generation in the specific area without adversely affecting the soaking performance across the entire plate, as the thickness change is localized and does not disrupt the overall heat distribution pattern.
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 effectively suppresses temperature reduction in specific areas, enhances heat generation, and simplifies wiring, thereby improving the soaking performance and heat distribution around low-temperature regions.
Implementation Method 1
the specific area surrounding portion has a smaller cross-sectional area and larger resistance than the normal portion of the heater electrode. Therefore, an amount of heat generated when a current is applied to flow through the heater electrode is larger in the specific area surrounding portion than in the normal portion
Data Source
AI summary
A ceramic heater including a heater electrode embedded in a plate made of ceramic, wherein, of the heater electrode, a specific area surrounding portion surrounding a specific temperature area in which temperature of the plate becomes low has a smaller thickness than a normal portion of the heater electrode.