Glass Membrane Bed Sagging for Pressure Sensor Overload Resistance
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Solution Overview
Problem
Manufacturing pressure sensors with reproducible and cost-effective membrane beds that match the natural pressure-dependent deformation of measuring membranes is challenging, especially for silicon platforms, due to limitations in bonding methods and material processing techniques.
Innovation Solution
A pressure sensor design featuring a glass layer with a contour formed by sagging an unsupported region of a glass plate under increased temperature and subsequent cooling, which serves as the membrane bed, providing support to the measuring membrane during overload, and is connected to a semiconductor platform using anodic bonding or other methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bonding methods (eutectic bonding or silicon direct bonding) are used to join silicon chips, then hermetic sealing and fixed connection are achieved, but manufacturing yield and reproducibility are insufficient
Solution Approach 1:
The invention changes the material parameter from silicon to glass for the membrane bed, enabling new manufacturing parameters (sagging at elevated temperature) that improve both yield and reproducibility while maintaining hermetic sealing properties
Solution Approach 2:
The invention replaces complex bonding processes with a thermal sagging process where a glass plate is heated to form the membrane bed contour through gravity-induced deformation, eliminating the need for precise mechanical bonding operations
2Manufacturing precision
If gray scale lithography or direct grinding/polishing methods are used to create spherically concave beds in silicon, then membrane bed contour is achieved, but manufacturing complexity and effort are greatly increased
Solution Approach 1:
The invention replaces complex mechanical processing (grinding, polishing, lithography) with a thermal field process where elevated temperature causes the glass plate to sag and form the desired contour automatically under gravity
Solution Approach 2:
The invention utilizes the phase transition of glass from rigid to soft state at elevated temperature, allowing the material to deform and form the membrane bed contour, then transitions back to rigid state upon cooling to maintain the formed shape
3Manufacturing precision
If micromechanical processing or hot embossing is used to prepare glass layer surface contour, then membrane bed support function is achieved, but manufacturing cost and complexity increase
Solution Approach 1:
The invention replaces micromechanical processing and hot embossing with thermal sagging, where the glass plate naturally forms its contour through temperature-induced deformation without requiring complex tooling or processing equipment
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 approach enhances the yield and reproducibility of pressure sensor manufacturing, significantly increasing overload resistance from 1 bar to at least 160 bar for a 10 mbar measuring range, and up to 500 bar for larger ranges, while maintaining a smooth surface to prevent stress on the measuring membrane.
Implementation Method 1
the contour of the membrane bed is obtainable by a sagging of an unsupported region of a glass plate, which forms the glass layer at increased temperature
Implementation Method 2
sagging of an unsupported region of a glass plate, which forms the glass layer at increased temperature, due to the force of gravity on the unsupported region of the glass plate
Implementation Method 3
the measuring membrane is contactable with at least one pressure and has a pressure-dependent elastic deformation
Data Source
AI summary
The pressure sensor of the invention includes at least one platform, at least one measuring membrane 30, and a transducer, wherein the measuring membrane comprises a semiconductor material, wherein the measuring membrane, enclosing a pressure chamber, is secured on the platform, wherein the measuring membrane is contactable with at least one pressure and is elastically deformable in a pressure-dependent manner, wherein the transducer provides an electrical signal dependent on deformation of the measuring membrane, wherein the platform has a membrane bed, on which the measuring membrane lies in the case of overload, in order to support the measuring membrane, wherein the membrane bed 21 has a glass layer 20, whose surface faces the measuring membrane and forms a wall of the pressure chamber, wherein the surface of the glass layer has a contour, which is suitable for supporting the measuring membrane 30 in the case of overload, characterized in that the contour of the membrane bed 21 is obtainable by a sagging of an unsupported region of a glass plate at increased temperature, due to the force of gravity on the unsupported region of the glass plate, and subsequent cooling of the glass plate.