Captive Electrode Stem Thermal Isolation
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Solution Overview
Problem
Ion implantation systems face challenges in maintaining elevated temperatures within the chamber due to thermal conduction issues, leading to reduced component temperatures and potential mechanical stress, which affects the efficiency and robustness of the system.
Innovation Solution
The implementation of thermally isolated captive features in ion implantation systems, such as electrodes and workpiece holders, using captive fasteners with flared heads that minimize physical contact and reduce thermal conduction, allowing for mechanical attachment while maintaining high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If components are physically attached to clamps and base using traditional fastening methods, then mechanical connection is achieved, but thermal conduction increases causing components to operate at lower temperatures than desired
Solution Approach 1:
The patent introduces ceramic spacers as intermediary elements between metal components and the base. These spacers act as thermal barriers while maintaining mechanical connection, allowing components to be securely fastened while minimizing thermal conduction to the base, thus preserving higher operating temperatures.
Solution Approach 2:
The patent employs composite construction by combining metal components with ceramic spacer materials. The metal provides structural integrity and electrical conductivity where needed, while the ceramic material provides thermal insulation. This composite approach allows simultaneous achievement of mechanical strength and thermal isolation.
2Productivity
If the platen is maintained at elevated temperature to benefit processing, then processing efficiency improves, but thermal conduction to the cooled base increases energy loss and creates high stress concentration
Solution Approach 1:
Ceramic spacers serve as intermediary elements between the hot platen and the cooled base. They provide thermal isolation that prevents excessive heat transfer to the base, reducing energy loss while also preventing thermal stress concentration at the interface between hot and cold components.
Solution Approach 2:
The patent utilizes the vacuum environment of the ion implantation chamber as an additional thermal barrier. The vacuum eliminates convective and conductive heat transfer through gas molecules, further isolating the platen thermally from the base and reducing stress concentration.
3Strength
If traditional fastening methods are used to attach components, then mechanical attachment is achieved, but thermal conduction paths are created that reduce component temperature
Solution Approach 1:
The patent uses composite construction combining metal fasteners with ceramic spacers. The metal provides mechanical strength for secure attachment, while the ceramic material interrupts thermal conduction paths. This allows strong mechanical connection while maintaining higher component temperatures.
Solution Approach 2:
Ceramic spacers act as intermediary elements inserted between metal components and the base structure. They provide mechanical support and positioning while serving as thermal barriers, enabling strong attachment without creating direct thermal conduction paths.
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 effectively reduces thermal conduction, allowing components to operate at higher temperatures, reducing the need for additional heating methods and minimizing mechanical stress, resulting in a more robust and efficient ion implantation process.
Implementation Method 1
the temperature of each component is limited by the amount of thermal radiation emitted and the amount of conduction that draws heat away from these components through mating components
Implementation Method 2
The lack of gas between the two components eliminates heat transfer through convection
Implementation Method 3
the temperature of each component is limited by the amount of thermal radiation emitted
Data Source
AI summary
Thermally isolated captive features disposed in various components of an ion implantation system are disclosed. Electrodes, such as repellers and side electrodes, may be constructed with a captive feature, which serves as the electrode stem. The electrode stem makes minimal physical contact with the electrode mass due to a gap disposed in the interior cavity which retains the flared head of the electrode stem. In this way, the temperature of the electrode mass may remain higher than would otherwise be possible as conduction is reduced. Further, this concept can be applied to workpiece holders. For example, a ceramic platen is manufactured with one or more captive fasteners which are used to affix the platen to a base. This may minimize the thermal conduction between the platen and the base, while providing an improved mechanical connection.