CMUT Microarray with Hyperbolic Paraboloid Geometry

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Solution Overview

Problem

Existing processes for fabricating capacitive micromachined ultrasonic transducers (CMUTs) require precise manufacturing tolerances, limiting the widespread adoption of CMUT sensor arrays in commercial applications due to challenges with noise immunity and frequency interference.

Innovation Solution

The use of benzocyclobutene (BCB) as a structural component in a silicon wafer construct for CMUTs, combined with a hyperbolic paraboloid shaped sensor configuration, allows for improved manufacturing methods and adjustable operating frequencies, enabling better noise immunity and programmable bandwidth control, which minimizes frequency interference and enhances sensor array design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional CMUT fabrication processes are used, then manufacturing precision can be achieved, but device complexity and production difficulty increase significantly

Engineering Contradiction:

Improvemanufacturing precisionVSAvoiddevice complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The fabrication process is divided into separate stages: first forming the diaphragm structure with air gaps using BCB adhesive layers, then adding metal layers and electrodes in subsequent steps. This segmentation allows each stage to be optimized independently, reducing overall process complexity while maintaining precision

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

BCB adhesive layers serve as intermediary materials that enable precise air gap formation and wafer bonding. These adhesive layers act as spacers and bonding agents, simplifying the fabrication process by eliminating the need for complex alignment and bonding mechanisms

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If precise manufacturing tolerances are maintained, then sensor reliability improves, but productivity and commercial scalability decrease

Engineering Contradiction:

Improvesensor reliabilityVSAvoidproductivity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Air gaps are formed preliminarily during the diaphragm structure formation stage using BCB adhesive layers, rather than requiring precise control during final assembly. This preliminary action ensures consistent gap dimensions across production while maintaining reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The use of BCB adhesive layers with controlled thickness parameters enables precise air gap formation through material property control rather than mechanical tolerancing. This parameter-based approach facilitates scaling while maintaining consistency

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If fixed frequency operation is used, then device simplicity is maintained, but adaptability to different environments and applications is reduced

Engineering Contradiction:

ImproveadaptabilityVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The sensor array is designed with adjustable operating frequencies through programmable control of the CMUT elements. This dynamic capability allows the system to adapt to different applications (vehicle blind-spot monitoring, autonomous driving) without requiring multiple fixed-frequency devices

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The sensor array incorporates multiple CMUT elements that can be selectively activated and configured for different frequency ranges and beam patterns. This multi-functionality enables a single device to serve multiple applications while maintaining manageable complexity through integrated control

Inventive Principle:

Principle #6Universality (Multi-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

This approach results in a more reliable and versatile ultrasonic sensor system capable of operating effectively in various environments with improved noise immunity and frequency adaptability, suitable for applications such as vehicle blind-spot monitoring and autonomous driving.

Implementation Method 1

benzocyclobutene (BCB) as a structural component in the Z-axis... BCB adhesive layers adding to the Z-height of the assembled wafer complex

Methodology Applied

Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

capacitive micromachined ultrasonic transducers (CMUT)... capacitive micromachined ultrasonic transducer (CMUT) based assembly sensor

Methodology Applied

Scientific EffectCapacitive micromachined ultrasonic transduction:

Implementation Method 3

hyperbolic paraboloid geometry beam forming array... discretized hyperbolic paraboloid geometry... hyperbolic paraboloid shaped sensor configuration

Methodology Applied

Scientific EffectGeometric beam forming: Geometry

Data Source

PatentUS9364862B2Ultrasonic sensor microarray and method of manufacturing same

Publication Date: 2016.06.14 UNIVERSITY OF WINDSOR

AI summary

A sensor assembly including one or more capacitive micromachined ultrasonic transducer (CMUT) microarray modules which are provided with a number of individual transducers. The microarray modules are arranged to simulate or orient individual transducers in a hyperbolic paraboloid geometry. The transducers/sensor are arranged in a rectangular or square matrix and are activatable individually, selectively or collectively to emit and received reflected beam signals at a frequency of between about 100 to 170 kHz.