Gas Feedthrough Assembly with Dielectric Tube Gap
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Solution Overview
Problem
Chemical vapor deposition (CVD) processing chambers face issues with thermal decomposition of metal-organic precursor gases on the inner surfaces of conventional dielectric gas feedthroughs, leading to contamination and quality defects in deposited films.
Innovation Solution
A gas feedthrough assembly featuring a dielectric body with a channel and a dielectric tube where the inner diameter of the channel is greater than the outer diameter of the tube, creating a gap to minimize thermal decomposition, using materials like quartz or polytetrafluoroethylene (Teflon) for the tube, and employing o-rings for thermal insulation and vacuum sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric gas feedthrough is used to flow process gases, then gas delivery function is achieved, but thermal decomposition of precursor gas occurs on inner surfaces of conduits
Solution Approach 1:
The gas feedthrough is segmented into multiple components: an outer dielectric body with channels, an inner dielectric tube, and thermal insulation material in the gap between them. This segmentation allows each component to perform its specific function - the inner tube contacts the gas, the outer body provides structural support and electrical isolation, and the insulation material prevents heat transfer to the conduit walls where decomposition occurs.
Solution Approach 2:
Thermal insulation material is introduced as an intermediary substance in the gap between the inner dielectric tube and outer dielectric body. This intermediary layer blocks heat transfer from the heated outer body to the inner tube walls, preventing thermal decomposition of the precursor gas while maintaining the structural integrity and electrical isolation of the feedthrough assembly.
2Stability of the object's composition
If the dielectric tube is tightly fitted in the channel, then structural stability is improved, but cleaning becomes difficult
Solution Approach 1:
The inner dielectric tube is designed as a separate, extractable component that can be removed from the outer dielectric body. This allows the inner tube to be easily taken out for cleaning or replacement without disassembling the entire feedthrough assembly, while still providing structural stability when installed. The tube can be extracted through the gas inlet port, cleaned separately, and reinserted to maintain film quality.
3Manufacturing precision
If thermal insulation is added to prevent decomposition, then film quality is improved, but device complexity increases
Solution Approach 1:
Thermal insulation material is applied locally only in the gap region between the inner dielectric tube and outer dielectric body, where heat transfer occurs. This localized application prevents thermal decomposition at the critical interface without requiring insulation throughout the entire assembly. The insulation material fills only the necessary space to block heat transfer paths, maintaining film quality while minimizing added complexity.
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
The solution effectively reduces thermal decomposition and contamination of substrates, simplifies cleaning by isolating the tube for removal and reinsertion, and maintains film quality by minimizing precursor gas accumulation on conduit walls.
Implementation Method 1
employing o-rings for thermal insulation and vacuum sealing
Implementation Method 2
employing o-rings for thermal insulation and vacuum sealing
Data Source
AI summary
A gas feedthrough assembly and processing apparatus using the same are disclosed herein. In some embodiments, the gas feedthrough assembly, includes a dielectric body; at least one channel extending through the dielectric body; and a dielectric tube disposed within the at least one channel, wherein an inner diameter of the at least one channel is greater than an outer diameter of the dielectric tube such that a gap is formed between an outer wall of the dielectric tube and an inner wall of the at least one channel.