cmut patent

Fraunhofer IPMS

New applications for ultrasound technology through CMUTs

Anartz Unamuno

26-09-2013

Fraunhofer IPMS

Anartz Unamuno I 26.09.2013 I slide 2

Agenda Capacitive Micromachined Ultrasonic Transducers (CMUT)

What is ultrasound

1o1 ultrasound transducers

Comparison Piezoelectric & CMUT

History of CMUTs

Challenges CMUT & IPMS

Strengths, Weaknesses, Opportunities, Threads

Initial results of IPMS CMUTs

Current research for CMUT applications (worldwide)

Conclusion

Fraunhofer IPMS


What is ultrasound?

Sample applications:

Medical imaging

Non-destructive testing

Level sensors

Speed sensors

Etc T.G. Leighton / Progress in Biophysics and Molecular Biology 93 (2007) 383

Images form Wikipedia search: Ultrasound

Fraunhofer IPMS


1o1 -- Ultrasonic transducers

Oralkan O., 2002

Capacitve Micromachined Ultrasonic Transducer

Piezoelectric Transducer

Image form Wikipedia search: Piezoelectricity

Mechanical displacement generates US waves

Fraunhofer IPMS


Advantages -- Piezoelectric & CMUTs transducers

Piezoelectric CMUT

Accepted technology CMOS integration

Reliability(*) Batch production reduced cost

Output acoustic pressure(*) RoHS compatible

Tight parameter specification

High temp. capable (ca. 800 C)

Scalability (size, shape, array, 2D)

Axial resolution

(*) Two factors that need to be addressed on CMUTs

Solving these two, CMUTs should be a winning technology!

Fraunhofer IPMS


History of CMUTs

Khuri-Yakub, http://www-kyg.stanford.edu/khuriyakub/opencms/en/research/cmuts/History/index.html

A MEMS device researched over the last 20 years

But no products on Euro nor US market using CMUTs yet!!

Fraunhofer IPMS


Challenges of fabricating CMUTs matches Fraunhofer IPMS expertise

Many issues have been previously solved at IPMS

Requirement Fraunhofer IPMS has marketed product

Large arrays of MEMS elements with quasi-identical performance

High voltage drive for capacitive MEMS

Low noise amplifiers or receive side

Integration MEMS-CMOS

Material expertise (process control)

Testing capabilities

Infrastructure to access and service small-to-medium size customers

US system integration

Fraunhofer IPMS


Testable CMUT devices

Work at IPMS -- Electrically testable 1D CMUT array

Fraunhofer IPMS


Work at IPMS -- Electrical impedance measurement

Fraunhofer IPMS


Resonance frequency spread, SD = 17 kHz (62 array elements)

Work at IPMS -- Resonance frequency distribution

Fraunhofer IPMS


Applications Intra Vascular UltraSound (IVUS)

Khuri-Yakub, 2009

Degertekin, 2012

Fraunhofer IPMS


Applications Harsh environment

Reference 1

High Temperature

High Pressure

1. Kupnik et Al., US patent 7,843,022 2. M.-C. Ho, M. Kupnik, K. K. Park, K. Eckhoff, and B. T. Khuri-Yakub, Wide pressure range

operation of air-coupled CMUTs, in Proc. IEEE Ultrasonics Symposium, pp. 93-96, 2012.

Reference 2

Reference 2

Fraunhofer IPMS


Applications Chemical sensors

Almira Ramanaviciene, Darius Virzonis, Gailius Vanagas and Arnas Ramanavicius, Capacitive micromachined ultrasound transducer (cMUT) for immunosensor design, Analyst, 2010, 135, 1531 DOI: 10.1039/c0an00104j

Fraunhofer IPMS


Applications Neural stimulation

1. Omer Naor et al, Towards multifocal ultrasonic neural stimulation II: design considerations for an acoustic retinal prosthesis, J. Neural Eng. 9 026006, 2012

2. Menz, Michael D - Oralkan, Omer - Khuri-Yakub, Pierre T - Baccus, Stephen A, Precise neural stimulation in the retina using focused ultrasound, The Journal of neuroscience: the official journal of the Society for Neuroscience, Vol. 33, No. 10

Reference 1

Fraunhofer IPMS


Conclusions

CMUTs enable novel ultrasonic applications

CMUTs should not be seen as a replacement for pezoelectric transducers, but they are the only option in some applications (e.g. High temp, large 2D array integration, etc.)

Technology is reaching a mature state to be deployed to the markets.

IPMS has one of the few fabrication facilities around the world, where it is possible to produce large MEMS arrays at tight tolerances.

Several team around the Globe are developing clever applications to make use of the CMUT capabilities.

Fraunhofer IPMS


Thanks!

cmut patent

Documents