Acoustic Microelectronic Device Bridge Insulation
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Solution Overview
Problem
Current acoustic transducer manufacturing techniques face challenges in maintaining mechanical reliability of membrane suspension and achieving effective acoustic insulation while allowing for electrical connection, particularly due to the obstacles posed by trenches used for insulation, which hinder wave transmission and electrical addressing.
Innovation Solution
The introduction of a bridge connecting opposite edges of an acoustic insulation trench, allowing for effective acoustic insulation around the membrane while enabling simplified electrical connection from outside the trench, forming an acoustic insulation box and facilitating electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If trenches are formed for acoustic insulation, then acoustic insulation is improved, but electrical connection and wave transmission are hindered
Solution Approach 1:
The device is segmented into distinct functional zones: acoustic insulation trenches are formed in the substrate to isolate membranes acoustically, while bridges are created to span these trenches and provide separate pathways for electrical connections. This segmentation allows acoustic insulation and electrical connectivity to coexist without interference.
Solution Approach 2:
Bridges serve as intermediary structures that connect opposite edges of the trenches. These bridges provide a medium through which electrical signals can pass while maintaining the acoustic isolation provided by the trenches. The bridges act as mediators between the acoustically isolated zones, enabling electrical addressing without compromising acoustic insulation.
2Object-affected harmful factors
If trenches are formed for acoustic insulation, then acoustic insulation is improved, but wave transmission is obstructed
Solution Approach 1:
The substrate is given different local qualities: trenches are formed in specific locations to provide acoustic insulation where needed, while bridges are created in strategic positions to maintain wave transmission pathways. This local differentiation allows the substrate to simultaneously provide acoustic isolation and facilitate wave propagation in different regions.
3Volume of moving object
If membrane thickness is reduced for microtechnology scaling, then device miniaturization is improved, but mechanical reliability deteriorates
Solution Approach 1:
The membrane structure employs composite material construction with multiple layers including piezoelectric materials, electrodes, and structural support layers. This composite approach allows the membrane to maintain adequate mechanical strength and reliability even as the overall device is scaled down to thin dimensions, as each layer contributes specific mechanical and functional properties.
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 solution provides continuous acoustic insulation and allows for easy electrical connection, addressing the limitations of existing methods by maintaining mechanical reliability and improving wave transmission while simplifying the manufacturing process.
Implementation Method 1
One such technique uses piezoelectricity. Such a transducer, known as a 'Piezoelectric Micromachined Ultrasonic Transducer' or by its acronym PMUT, generates and/or detects an ultrasonic wave by means of a membrane set in motion by a piezoelectric actuator
Implementation Method 2
Other transducers operate using capacitive control. Such a transducer, known as a Capacitive Micromachined Ultrasonic Transducer (CMUT), generates and/or detects an ultrasonic wave by means of a membrane set in motion by capacitive contact between the membrane and the bottom of the CMUT cavity
Data Source
Figure 1~3
Figure 4~5
Figure 6a~10
AI summary
The present invention relates to an acoustic microelectronic device comprising a carrier (1), a set of at least one membrane (3) suspended on one side (21) of the carrier (1) above a cavity via an anchoring zone (31), and at least one acoustically insulating trench (62a,b,c,d; 63a,b) that is placed adjacent to the membrane (3), characterised in that it includes at least one bridge (64) connecting portions of two opposite edges of the trench (62a,b,c,d; 63a,b) and located overhanging at least one zone of the trench (62a,b,c,d; 63a,b) so as to form, in said zone of the trench, an acoustically insulating well (65) below the bridge (64).