Philips Innovation Services CMUT ready to make some noise – Interview by Yole Développement

In the last decade, MUT technologies have created a high level of excitement. Today, CMUT (capacitive micro-machined ultrasonic transducer), using capacitive properties, has pirevealed an excellent alternative to bulk piezoelectric modules for making products smaller, with a high level of integration, and at a lower cost. A number of applications are possible, from handheld non-destructive tests for industrial markets, to medical imaging. As described in Yole Développement (Yole)’s latest report, Ultrasound Sensing Technologies for Medical, Industrial, and Consumer Applications 2018, huge market opportunities in ultrasonic-based products for imaging applications are now available for CMUT to penetrate. This market’s total value is expected to reach $6B in 2023.

Philips Innovation Services is a major player in the development and manufacturing of CMUT devices. The company has spent over a decade developing CMUT technologies, solving various technological challenges along the way. Jérôme Mouly, Senior Technology & Market Analyst & Business Developer, specialized in microtechnologies for inkjet & bioMEMS sensors, recently met with Paul Bekkers, Business Development Manager at Philips Innovation Services, who shares with our readers his “ultrasonic” experience.

Jérôme Mouly (JM): Can you summarize Philips Innovation Services and the company’s offering?

Paul Bekkers (PB): At Philips Innovation Services, we want our clients to be successful in delivering their innovations to the market, where they can matter to their customers and society as a whole. Our mission is simple: to accelerate innovation, from start-up to multinational. We offer services in prototyping, process development, and production in MEMS as well as in micro devices.

Our MEMS foundry specializes in low to medium-volume custom MEMS manufacturing of 6 and 8-inch wafers. It is a state-of-the-art 2,650 m², pure-play MEMS foundry located on the High Tech Campus in Eindhoven, the Netherlands. We offer the flexibility to use substrate materials like silicon, SOI, GaAs, glass, quartz, and CMOS-wafers, and we work with ISO 13485 and ISO 9001-quality systems.

Our Micro Devices facility is fit for prototyping as well as volume production. Our services are industrial PCBA prototyping, assembly of high-end PCBAs, and interconnect architecture & prototyping.

Apart from these services, we also offer some technologies that we developed together with Philips Research. CMUT (capacitive micro-machined ultrasonic transducer) is one of them. In early 2017 we started sampling CMUT technology. Since then, the number of applications we are working on with customers has grown dramatically.

 (Source: Philips Innovation Services)

JM: Philips Innovation Services is developing a CMUT (capacitive micro-machined ultrasonic transducer) technology. What are the key process steps and materials used?

PB: I always like to joke that our CMUT is just a few layers on top of a silicon wafer. We have worked very hard to make our process simple, using only standard materials. Leveraging our strengths in stress-control (for membranes) and high-quality dielectrics, we realized a key feature in our CMUT platform, the so-called “collapse mode”. Our elegant process allows high levels of integration and customization. For example, we can directly process on top of CMOS-ASIC wafers, and even make curved or flexible chips. In my experience, this combination of high performance, volume manufacturing, and level of integration is unique. This makes our CMUT technology so interesting for use in a wide variety of applications. And obviously, it is lead-free.

JM: It took years for the first products using MUT technologies to arrive on the market. What were the main development challenges at sensor level and regarding electronic integration?

PB: Since the first MUT publication of Haller and Khuri Yakub, there have been many obstacles to overcome. The commonly acknowledged challenges of MUT technology were drift, lifetime, pressure output, the acoustic interface, and reliability/reproducibility. These were our main challenges in the early stages of our development. In addition, we spent quite some effort in achieving a single-wafer process and versatile technology platform.

Electronic integration of our transducers is quite standard: our transducers don’t need special signal conditioning. Our lead customers were able to easily connect and operate our transducers in their setups. This simplicity enables our customers to make breakthrough products, optimized for their markets.

JM: How does Philips Innovation Services differentiate itself from competitors?

PB: The single-wafer process is a unique feature, essential for 3D-imaging and high-frequency applications. Also, our collapse mode brings the pressure output and sensitivity of our CMUT transducers to premium levels, which benefits all applications. Finally, our strong modeling expertise facilitates the design of optimized transducers for our customers, to fit both their application and their business case.

JM: Today the ultrasound modules market is almost exclusively based on bulk piezoelectric technology, but we see a clear trend towards MUT (micro-machined ultrasonic transducer) technology for the next five years thanks to new applications and technology readiness. Do you think that MUT technologies will open new markets, or can we also think of MUT as a replacement technology for bulk piezoelectric?

PB: We think that there will be a place for both bulk and MUT transducer technology. In these early years of MUT technology market introduction, applications that benefit most will be frontrunners, particularly products that need high-volume, cost-efficient manufacturing. Typically these are found in industrial and medical monitoring applications, and home-care.

When MUT technology becomes widely used, it will begin replacing many lower-volume bulk applications, swapping manual assembly with a reliable semiconductor process.

JM: Handheld medical ultrasound probes seem to be the first CMUT application in mass-market, with the arrival of newcomers like Butterfly Network. What are the applications targeted by your CMUT technology?

PB: At Philips, the CMUT technology was originally developed for use in medical imaging. You can imagine this application area attracts a lot of interest. Next to that, we work with leading companies on high-volume applications in markets like industrial monitoring and automotive.

JM: PMUT is the direct competing technology for CMUT. What are the differences between these two technologies in terms of performance? Do these differences imply different applications?

PB: With PMUT, a one-wafer approach is nearly impossible. In performance, it is very hard to make a direct comparison, since there are so many varieties of these technologies.

JM: Artificial Intelligence (AI) is playing an increasing role in medical imaging diagnostics. How big is the convergence today between AI and democratization of ultrasound imaging? What is your vision for the future?

PB: That would be an answer best given by our CMUT customers. In general, we see a trend towards a real symbiosis of hardware and software. You do not have to solve all your technical issues in hardware; you cannot solve all your technical issues with software or apps. Clever data processing or artificial intelligence can add a lot of value to sensor measurements and even make it easier for everybody to interpret data. I think this will be an ongoing challenge.

JM: Anything you would like to announce to our readers?

PB: In December 2018 we will start sampling our new CMUT imaging transducer to select customers. Premium performance in a small form factor. Keep an eye on our LinkedIn page and the Philips Innovation Services website and stay informed about our progress.

Interviewee:

Paul Bekkers joined Philips in 2016 after a career in a large technology consultancy firm. He is part of the Philips MEMS & Micro Devices business development team, mainly responsible for the business development for Philips MEMS Foundry’s large set of microfabrication capabilities. His primary focus is the marketing of the Philips cMUT technology. With a strong Physics education (and MEMS specialization), having lead teams and having provided technology consultancy to a wide range of companies and institutes, he now puts his enthusiasm and innovative technology mindset to work to get the world acquainted with the awesome work being done at the Philips MEMS Foundry.

Interviewer:

Jérôme Mouly serves as a Senior Technology & Market Analyst & Business Developer, specialized in microtechnologies for inkjet & bioMEMS sensors, within the Life Sciences & Healthcare division at Yole Développement (Yole).
He manages the day to day production of technology & market reports. He is also deeply involved in custom consulting projects such as strategic and marketing analyses.
In parallel, he is committed in the business development of the Life Sciences & Healthcare division activities at Yole.
Previously Jerome was strongly involved in support actions for value creation of smart miniaturized systems research projects at Yole Finance Innovation, part of Yole.
Along his career, Jérôme has developed a large network in the industry, being in touch with CEOs, CTOs, Marketing Managers, Business Development Managers…
Jérôme holds a Master of Physics from the University of Lyon (France).

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