Vacuum Measuring Cell With Integrated Thermal Container
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Solution Overview
Problem
Existing vacuum pressure sensors, particularly those using silicon diaphragms, are not suitable for high-temperature and chemically aggressive environments common in semiconductor processes, leading to corrosion and reduced accuracy, and existing heated measuring cells are bulky and inefficient with non-homogeneous temperature distribution.
Innovation Solution
A compact diaphragm vacuum measuring cell with an integrated heater and electronic circuitry, where the thermal container encompasses the measuring cell and is insulated to maintain a uniform temperature, allowing operation in aggressive environments with precise temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon diaphragm sensors are used for vacuum pressure measurement, then cost-effective production and higher pressure range measurement are achieved, but corrosion resistance in chemically aggressive environments and high-temperature operation are compromised
Solution Approach 1:
The patent employs a composite material structure where a silicon-based diaphragm sensor is integrated with a ceramic housing and coating system. The silicon diaphragm provides cost-effective manufacturing and pressure sensing capability, while the ceramic housing and protective coatings provide corrosion resistance against chemically aggressive environments such as fluorine and bromic acid, thus resolving the contradiction between ease of manufacture and reliability.
Solution Approach 2:
The patent introduces an inert or protected environment by coating the silicon diaphragm surface with corrosion-resistant materials and designing the ceramic housing to isolate the sensor from direct contact with aggressive process gases. This protective environment allows the silicon sensor to operate reliably in chemically aggressive vacuum processes without direct corrosion.
Solution Approach 3:
The patent modifies the operational parameters by introducing heated operation at elevated temperatures. The heating element raises the temperature of the measuring cell to prevent condensation of process gases on the diaphragm surface, thereby maintaining measurement accuracy and preventing corrosion-related degradation in high-temperature vacuum processes.
2Measurement precision
If heated operation is implemented to prevent condensation and improve high-temperature operation, then measurement accuracy in hot process environments is improved, but device complexity and energy consumption increase
Solution Approach 1:
The patent merges the heating function directly into the measuring cell structure by integrating a heating element within the ceramic housing, positioned to heat the diaphragm and measuring chamber. This integrated design achieves the desired temperature control for preventing condensation and improving measurement accuracy while minimizing additional device complexity compared to external heating systems.
Solution Approach 2:
The patent changes the thermal parameter by implementing controlled heating at specific temperature ranges suitable for vacuum process conditions. The heating system maintains the measuring cell at elevated temperatures to prevent condensation of process gases, thereby improving measurement precision without requiring excessive temperature increases that would unnecessarily complicate the system.
3Temperature
If existing heated measuring cells are used, then high-temperature operation is achieved, but compact design and homogeneous temperature distribution are compromised due to bulky structure
Solution Approach 1:
The patent segments the heating function into a compact, integrated heating element positioned directly within the measuring cell chamber, rather than using external heating jackets or bulky heating assemblies. This segmented approach allows high-temperature operation to be achieved in a compact form factor with more homogeneous temperature distribution throughout the measuring volume.
Solution Approach 2:
The patent transitions from external or distributed heating approaches to an internally positioned heating element that radiates and conducts heat directly to the diaphragm and measuring chamber walls. This dimensional repositioning of the heat source within the compact cell structure enables efficient heat distribution and maintains compact overall device volume while achieving high-temperature operation.
Data Source
AI summary
The invention relates to a vacuum measuring cell device comprising a vacuum membrane measuring cell (8) having a connecting means (5, 6) arranged thereon for a communicating connection to the medium to be measured, an electronic system (34), which is electrically connected to the vacuum membrane measuring cell (8), and also comprising a heating arrangement (20, 21) for heating the vacuum membrane measuring cell (8) to a predefinable temperature value, wherein the heating arrangement (20, 21) substantially encloses the entire vacuum membrane measuring cell (8) such that said cell forms a thermal container (20). Said container constitutes a thermal body (20a) in the area of the connecting means (5, 6) and connecting means (6) are guided through it, the connecting means thereby being thermally contacted at least in some areas by the thermal body. The thermal container (20a) comprises a heating source (21) for the heating thereof. The thermal container (20) is substantially entirely enclosed by an insulating shell (22).