Micromechanical Sound Transducer Component with Al-Ge Bonding
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Solution Overview
Problem
Existing MEMS ultrasonic transducers face challenges in protecting electrical connections between piezoelectric elements and control circuits, maintaining a high piezo coefficient, and achieving a compact design while being cost-effective.
Innovation Solution
The development of a micromechanical component with a piezoelectric element on the diaphragm surface, using an aluminum-germanium bond connection structure and a reinforcement/gel-restriction structure, allows for high-temperature production, ensuring a high piezo coefficient and protecting electrical connections, while enabling a miniaturized design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electrical connections are exposed for easy access, then ease of operation is improved, but reliability deteriorates due to protection issues
Solution Approach 1:
The electrical connections are nested within a recess in the substrate, creating a protected chamber that shields bond wires and traces while maintaining accessibility through the recess opening. This nesting approach resolves the contradiction by providing both protection (reliability) and access (ease of operation) simultaneously.
Solution Approach 2:
A protective structure acts as an intermediary between the electrical connections and the external environment. This mediator element provides mechanical protection and environmental shielding while allowing electrical functionality to remain accessible, thus resolving the contradiction between protection and ease of operation.
2Manufacturing precision
If piezoelectric element is developed at high temperature, then piezo coefficient is improved, but manufacturing precision deteriorates due to temperature constraints
Solution Approach 1:
The substrate and electrical connection structures are prepared in advance with recesses and protective features before the high-temperature piezoelectric element development. This preliminary preparation allows the subsequent high-temperature process to proceed without compromising manufacturing precision, as the temperature-resistant structures are already in place.
Solution Approach 2:
The invention changes the material parameters of the substrate and bonding structures to withstand high temperatures. By selecting materials with appropriate thermal stability and designing temperature-resistant connection structures, the piezoelectric element can be developed at high temperatures while maintaining manufacturing precision.
3Volume of moving object
If component size is reduced for compact design, then volume is improved, but device complexity increases
Solution Approach 1:
Multiple functions are merged into the substrate structure: the substrate serves as both the mechanical base and the electrical connection carrier with integrated recesses. The protective structure combines mechanical protection, environmental shielding, and structural support functions. This merging reduces overall component volume while avoiding additional complex elements.
Solution Approach 2:
The electrical connections are arranged in a three-dimensional configuration with recesses providing vertical depth for protection. This dimensional approach allows compact packaging of electrical connections without increasing planar footprint, achieving volume reduction while maintaining protection functionality.
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 provides a micromechanical component with well-protected electrical connections, high piezo coefficient, and a compact design, suitable for various applications including medical technology, with enhanced durability and reliability.
Implementation Method 1
at least one piezoelectric element (22), which is situated on a first diaphragm surface (10a) of a diaphragm element (10) in such a way that the diaphragm element (10) can be deformed with the aid of the at least one piezoelectric element (22), and/or oscillations are able to be induced in the diaphragm element (10)
Implementation Method 2
the at least one electrically conductive bond connection structure (34) is an aluminum-germanium bond connection structure... the development of the at least one electrically conductive bond connection structure (34) from aluminum and germanium allows the at least one piezoelectric element (22) to be developed at a relatively high temperature of at least 400° C.
Data Source
AI summary
A micromechanical component for a sound transducer device. The component includes a diaphragm element which includes a first diaphragm surface and a second diaphragm surface which points away from the first diaphragm surface, and at least one piezoelectric element situated on and/or at the first diaphragm surface. The micromechanical component includes a substrate having at least one control and/or evaluation circuit developed thereon and/or therein, the first diaphragm surface pointing toward the substrate, and the substrate is attached to the diaphragm element at least via at least one an electrically conductive bond connection structure which is developed on and/or at the first diaphragm surface, from which the second diaphragm surface is pointing away, and the at least one piezoelectric element is electrically connected to the at least one control and/or evaluation circuit at least via the at least one electrically conductive bond connection structure.