Insulating Ring for CVD Electrode Holder Thermal Stress
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Solution Overview
Problem
Existing solutions for insulating and sealing electrode holders in CVD reactors face issues with thermal stress, leading to premature wear, leaks, and ground faults due to the use of materials with low thermal conductivity and brittleness, resulting in reduced reactor service time and increased costs.
Innovation Solution
A device with an electrically insulating ring made of a material with specific thermal conductivity and electrical resistance, combined with sealing elements secured in grooves of the electrode holder or floor plate, providing separate insulation and sealing functions and reducing thermal stress on the sealing elements through cooling and mechanical protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydrocarbon-based sealing body is used in the electrode holder, then sealing function is provided, but thermal protection is insufficient leading to premature wear and scorching
Solution Approach 1:
A ceramic ring is introduced as an intermediary component between the heating zone and the sealing body. This ceramic ring acts as a thermal barrier that protects the hydrocarbon-based sealing body from direct thermal exposure, allowing the seal to function without undergoing thermal degradation while maintaining its sealing effectiveness.
Solution Approach 2:
The sealing system is segmented into distinct functional zones: a ceramic ring that withstands high temperatures and provides thermal protection, and a hydrocarbon-based sealing body that provides sealing function in a cooler zone. This segmentation allows each material to operate within its optimal temperature range, extending overall system reliability.
2Device complexity
If the electrode holder structure is simplified, then device complexity is reduced, but thermal protection and sealing reliability deteriorate
Solution Approach 1:
The ceramic ring serves multiple functions simultaneously: it provides thermal protection for the sealing body, maintains the structural integrity of the electrode holder, and contributes to the overall sealing mechanism. This multi-functionality reduces the need for additional separate components, keeping the device complexity low while maintaining high reliability.
3Temperature
If cooling water is applied to protect sealing elements, then thermal stress is reduced, but ground faults and leaks occur due to insufficient protection
Solution Approach 1:
The ceramic ring is positioned beforehand to cushion and absorb thermal stress before it reaches the sealing elements. This pre-protection mechanism prevents thermal degradation of the sealing elements, eliminating the need for cooling water and avoiding associated risks of ground faults and leaks while maintaining electrical insulation integrity.
4Productivity
If high electrical voltage is applied to increase productivity, then deposition efficiency improves, but thermal and mechanical damage to sealing elements increases
Solution Approach 1:
The ceramic ring acts as a mediator that isolates the sealing elements from the high-voltage electromagnetic field and associated thermal effects. This protection allows high electrical voltage to be applied for improved deposition efficiency without compromising the thermal and mechanical integrity of the sealing elements.
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 extends the service life of sealing elements, maintains electrical insulation, and prevents leaks, thereby increasing reactor efficiency and reducing maintenance costs by allowing for greater electrical voltage application and longer operation without thermal or mechanical damage.
Implementation Method 1
The cooling water is fed into the first region thus formed in order thus to cool the reactor bottom
Implementation Method 2
The cooling water connections for the filaments may be in the form of quick-fit couplings
Implementation Method 3
an electrically insulating ring made of a material of construction having a specific thermal conductivity at room temperature of 1-200 W/mK, a sustained use temperature of no less than 400° C. and a specific electrical resistance at room temperature of more than 109 Ωcm
Implementation Method 4
at least two ring-shaped sealing elements for sealing between the electrode holder and the floor plate are provided
Implementation Method 5
the electrically insulating ring or the electrode holder or the floor plate comprises grooves in which the sealing elements are secured
Data Source
AI summary
Siemens CVD reactors are sealed in a manner which facilitates long production campaigns without refurbishing the seals, by the use of at least two seals, and an electrically insulating member having a thermal conductivity of from 1 to 200 W/mK, a sustained use temperature of at least 400° C., and a resistivity of more than 1·109 Ωcm.