Multi-zone heater with hermetic thermocouple channels
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Solution Overview
Problem
Current multi-zone heaters in semiconductor processing face limitations due to the inability to install multiple control thermocouples within the heater zones, leading to variations in resistance and non-repeatability of watt-density maps across units, which affects temperature control and film thickness uniformity.
Innovation Solution
A multi-zone heater design with independent thermocouples installed within each zone, routed through a hermetic channel or between plate layers, allowing for direct temperature monitoring and control while maintaining isolation from the processing environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple independent heater circuits are used to create multi-zone heaters, then the ability to change watt-density maps on-the-fly is improved, but the ability to install multiple control thermocouples is worsened due to the plate-and-shaft design limitation
Solution Approach 1:
The heater plate is divided into multiple independent heater zones with separate control circuits, allowing independent temperature control of different regions. This segmentation enables flexible watt-density map changes while the patent resolves the thermocouple limitation by providing multiple thermocouple mounting locations across different zones
Solution Approach 2:
The patent transitions from a single central thermocouple location to multiple thermocouple locations distributed across the plate surface in different radial zones. This spatial distribution in multiple dimensions allows each heater zone to have its own temperature monitoring point, resolving the contradiction between multi-zone heating capability and thermocouple installation limitation
2Device complexity
If a single control thermocouple is used at the center, then the heater design is simplified, but the temperature control precision across different zones is worsened
Solution Approach 1:
Each heater zone is equipped with its own control thermocouple located within that specific zone, allowing localized temperature measurement and control. This ensures that temperature feedback is representative of the actual conditions in each zone, improving temperature control precision while maintaining relatively simple heater design through modular zone implementation
3Measurement precision
If thermocouples are located outside the central shaft area, then temperature monitoring of outer zones is improved, but the hermetic sealing requirement is worsened
Solution Approach 1:
The patent introduces a hermetic seal structure that acts as an intermediary barrier between the process environment and the thermocouple leads. This seal allows thermocouples to be positioned in outer zones for accurate temperature monitoring while maintaining hermetic isolation to protect the thermocouples from corrosive process chemicals and maintain vacuum integrity
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 enables precise and repeatable temperature control across different heater zones, improving the uniformity of film thickness and reducing variations in resistance, thus enhancing the consistency of semiconductor processing.
Implementation Method 1
routed out from the shaft of the heater in a channel that is closed with a joining process that results in hermetic seal adapted to withstand both the interior atmosphere of the shaft and the process chemicals in the process chamber
Implementation Method 2
A multi-zone heater with a plurality of thermocouples such that different heater zones can be monitored for temperature independently
Implementation Method 3
By varying the voltages and currents applied to the different circuits, you can change the power levels in the locations of the individual circuits
Data Source
AI summary
A multi-zone heater with a plurality of thermocouples such that different heater zones can be monitored for temperature independently. The independent thermocouples may have their leads routed out from the shaft of the heater in a channel that is closed with a joining process that results in hermetic seal adapted to withstand both the interior atmosphere of the shaft and the process chemicals in the process chamber. The thermocouple and its leads may be enclosed with a joining process in which a channel cover is brazed to the heater plate with aluminum.