SilTerra, in collaboration with its partner, Microtech Ventures, a venture capital, investor and M&A advisor on sensors, MEMS, and microtechnology companies, recently hosted a webinar on Emerging PMUT Applications and Manufacturing Solutions. Teaming up with PMUT ecosystem industry players and technology partners including SoftMEMS, Onscale, Polytec and Carsem, this webinar was aimed providing a full-fledged commercialization perspective of PMUT-based solutions from a value chain aspect, covering market outlook, design, modeling and fabrication to packaging solutions for ultrasonic technologies. With this Digital Foundry lineup, any team utilizing SilTerra’s PMUT technology will have an accelerated time to market for their products compared to those utilizing the traditional wafer-based development approach.
The webinar was well-received with over 300 MEMS experts, technologists and enthusiasts from 158 organizations in 26 countries participating in this event.
A replay of the webinar is available below :
Speakers from the PMUT ecosystem shed some light on some of the key concepts and approaches that take place in the various stages in the PMUT value chain. The topics covered were :
Agenda 1 : Opening Remarks – PMUT Market Trends and Emerging Applications
Speaker : Dr. Mike Pinelis, President & CEO of Microtech Ventures,Inc.
In the opening address, Dr. Mike Pinelis unveiled the ultrasound sensing modules market outlook, highlighting that the best opportunities for PMUT in the next 5 years are expected to lie in gesture recognition for automotive applications, fingerprint sensors in consumer electronics, VR headsets, consumer user interfaces and medical wearables.
Agenda 2 : PMUT Manufacturing Processes and Platform Solutions
Speaker : Arjun Kumar Kantimahanti, Sr.Vice President of the MEMS, Sensors and Life Sciences Business Unit of SilTerra
As PMUT-based products enter the market, there is a need from companies to address more than one market. Hence, retargeting the frequencies of the PMUT could potentially help these companies meet the needs of their end-markets.
In enabling its customers accelerate their device time-to-market, Arjun Kumar highlighted that SilTerra adopts the modular approach in PMUT development to target a wide range of applications at various frequencies. He introduced the key PMUT platforms in SilTerra which cover Monolithic PMUT, C-SOI PMUT and Bulk PMUT. The Monolithic PMUT is targeted for fingerprint and touch sensors (15-50Mhz); and short range imaging in medical applications (0.5MHz – 15MHz). The C-SOI PMUT is targeted for gesture control and haptic sensors (500KHz – 750 KHz), while the Bulk PMUT is targeted for industrial sensing (< 500KHz).
Customers have the option of building PMUT cells with or without integrated CMOS readout circuits. While SilTerra has traditionally been a fab for CMOS and analog devices, it is able to deliver the the equivalent level of services for PMUTs by providing customers with silicon-validated layout guidelines; customization of process modules, prototyping services using Multilayer Masking; and qualification of PMUT devices for pilot volumes and product ramp.
Agenda 3 : PMUT Design and Modeling Considerations
Speaker : Dr. Mary Ann Maher, CEO of SoftMEMS
Dr. Mary Ann Maher spoke about the design aspects of MEMS PMUT devices. One of the key driving trends in PMUT design is that imaging arrays are becoming increasingly larger and complex. On the other hand, trends towards miniaturization is driving the demand for more handheld devices to be made available. From a material perspective, there is increasing interest in scandium doped aluminium nitride as the piezoelectric layer of the PMUT and SilTerra is one of the few fabs in this world with this capability. As devices trend towards increased performance and miniaturization, PMUT devices need to be characterized in terms of acoustics, mechanics and electrostatics.
The greatest challenge in designing PMUT devices lie in the process variations that happen during fabrication. Manufacturing variations could arise as a result of equipment variance; process variance; and wafer and material variance; which in turn, affects device yield and performance. Dr. Mary Ann also gave the audience an overview of the flow in PMUT fabrication modeling used for SilTerra’s PMUT devices.
Agenda 4 : Digital Prototyping of MEMS PMUT Devices
Speaker : Ian Campbell, CEO of OnScale
In the 4th session, Ian Campbell shared about PMUT digital prototyping which happens after the device layout, 2D & 3D modeling are done. Digital prototyping and digital qualification is aimed at understanding the performance and yield of the PMUT device before it goes through an actual foundry process; hence this could potentially save device owners a lot of risk, cost and time to market. A typical digital qualification study on Onscale’s platform involves the parameterization of geometry variables such as cavity diameter; electrode, piezo and elastic layer thickness; to match electrical KPIs of the PMUT device such as resonant frequency, displacement and capacitance. Understanding these measurements upfront without needing to use large physical wafer samples could potentially save PMUT device owners millions of dollars in physical prototyping costs and potentially years of time in the MEMS R&D cycle. Ian also presented simulation results of multiple device parameters in 2D and 3D.
Agenda 5 : Characterization of PMUT Devices
Speaker : Jerome Eichenberger, Business Development Manager at Polytec
Polytec’s expertise lie in laser beam non-contact methods for capturing the mechanical response of structures in the macro and micro world. In a typical end-user application of the PMUT such as in ultrasonic imaging, Jerome Eichenberger explained that the quality of the picture can be compromised due to variance in the manufacturing process. By understanding the dynamic behavior of the PMUT, engineers can then optimize the performance of the device. Jerome stressed on the importance of knowledge in mechanical responses to accurately perform model validation. He also explained about Laser Doppler Vibrometry in the measurement of PMUTs. The presentation included a demo on the vibrometer data measurements obtained with SilTerra’s PMUT array.
Agenda 6: Carsem Advanced Packaging Technologies for PMUT Devices
Speaker : Dr. John Miranda, VP of Business Development & Sales at Carsem
In this session, Dr. John Miranda provided an overview of the range of technologies available for MEMS and PMUT packaging such as System-in-Package, flip-chip packaging, to name a few. On key considerations for PMUT assembly, he explained that PMUTs are thin, free-standing membranes and are thus, prone to damage during handling and packaging. Dr. John shared two packaging configurations conceptualized between Carsem and SilTerra for application in haptics and fingerprint sensing, respectively.
SilTerra would like to take this opportunity to thank its partners and all those who participated in this webinar for making this event a success. Participants raised thoughtful questions during the Q&A, indicating a great level of engagement delivered by the speakers.