Substrate Temperature Control Device with Flow Rate Adjustment
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Solution Overview
Problem
Current temperature control methods for semiconductor wafers in plasma processing apparatuses are inefficient, as they struggle to maintain uniform temperature across the wafer due to varying heat input and output, leading to non-uniform plasma density and temperature distribution, and require complex RF filtering to prevent RF noise, which increases costs and limits rapid temperature changes.
Innovation Solution
A temperature control device with a mounting table featuring independent temperature control systems, circulation channels for heated and cooled fluids, and flow rate control units to adjust fluid flow ratios, allowing for precise temperature control of different regions of the substrate, enabling uniform temperature maintenance and rapid temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a heater (e.g., thermoelectric element module or ceramic) is provided directly under the substrate to heat the susceptor, then the heating rate can be increased, but RF leakage occurs from wire lines requiring RF filters which complicates equipment and increases cost
Solution Approach 1:
The invention extracts the heating function from a separate heater component and integrates it into the coolant circulation system by heating the coolant before it enters the susceptor. This eliminates the need for separate heater wire lines that would require RF filters, thereby reducing equipment complexity while maintaining rapid heating capability.
Solution Approach 2:
The coolant circulation system is given multiple functions: it not only cools the susceptor but also serves as the heating medium when heated coolant is supplied. This multi-functionality eliminates the need for separate heating and cooling systems, reducing overall equipment complexity.
2Speed
If a heater is provided directly under the substrate to increase heating rate, then temperature control speed improves, but RF noise and RF power loss cannot be completely suppressed even with RF filters
Solution Approach 1:
The invention removes the problematic heater component that causes RF leakage and replaces it with a heated coolant system. This extraction eliminates the source of RF noise while maintaining the ability to rapidly heat the susceptor through thermal conduction from the heated coolant.
3Device complexity
If the entire susceptor has the same temperature through uniform coolant circulation, then the system is simple, but thermal conductivity between substrate and susceptor cannot vary by portion making uniform temperature control difficult
Solution Approach 1:
The invention divides the susceptor into multiple temperature control zones (first and second regions) with independent coolant circulation channels. This segmentation allows different portions of the susceptor to have different temperatures, enabling precise control of thermal conductivity variations across the substrate surface.
Solution Approach 2:
The invention applies different temperatures to different regions of the susceptor by controlling coolant flow rates in separate channels. This local quality approach allows optimization of temperature distribution to match the specific thermal requirements of different substrate regions, improving overall temperature uniformity.
4Temperature
If the susceptor is cooled by circulating coolant to maintain uniform temperature, then cooling function is provided, but heating function requires separate heater units increasing complexity
Solution Approach 1:
The coolant circulation system is designed to perform both cooling and heating functions. By controlling the temperature of the coolant supply and its flow rate, the same system can remove heat when needed or add heat when needed, eliminating the requirement for separate heating and cooling units.
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 solution allows for independent control of substrate temperatures across different regions, ensuring uniform temperature distribution and reducing the time required for temperature adjustments, while simplifying the equipment structure and reducing costs by eliminating the need for complex RF filtering.
Implementation Method 1
temperature control members capable of independently controlling respective temperatures of a plurality of regions of a mounting table for mounting thereon the target substrate... by heating or cooling the target substrate by circulating fluid in a temperature control unit
Implementation Method 2
controlling the flow rates of the heat transfer medium supplied from both circuits to the susceptor
Data Source
AI summary
A temperature control device for a target substrate includes a mounting table having temperature control members respectively provided in temperature systems to control temperatures of regions of the target substrate to respective predetermined temperature levels; circulation channels through which fluids passing through the temperature control members flow; and heating channels each for flowing therein a heated fluid having a higher temperature compared to the fluids circulating in the circulation channels. The device further includes cooling channels each for flowing therein a cooled fluid having a lower temperature compared to the fluids circulating in the circulation channels; and joining units that join the circulation channels to build the respective temperature control systems, the joining units having flow rate control units that controls flow rate ratios of the fluids supplied from the respective channels to the temperature control members.