Automotive: sensor sprawl is on the rise – The chronicles by Yole SystemPlus

As recently stressed by Yole Intelligence, part of Yole Group, the automotive semiconductor sensor market is expected to reach US$14 billion in 2028, with a 10% CAGR during 2022-28. By integrating a greater quantity and variety of sensors into vehicles, OEMs address the growing demand for enhanced safety, comfort, and efficiency. Initially reserved for high-end models, sensors are now set to conquer the entire automotive industry and pave the way for autonomous driving.

In the Automotive Safety Inertial Sensors Comparison and Automotive Navigation Inertial Sensor Comparison reports, Yole SystemPlus, also part of Yole Group, focuses on MEMS inertial and magnetic 2D position sensors in automotive applications and provides insights into their structure, technology, process integration, and manufacturing cost.

MEMS inertial sensors in safety and navigation applications

Inertial sensors are now crucial to many automotive applications, from ADAS (Advanced Driver Assistance Systems) and safety to user experience (including navigation), body and chassis, and powertrain systems. For these devices, the automotive safety market is expected to reach US$1.21B by 2028, compared to US$1.1B in 2022, while the automotive navigation market is expected to reach US$95M by 2028, compared to $28M in 2022 (Source: Yole Intelligence). Capacitive MEMS inertial sensors – provided by the major players, namely BOSCH (undeniable leader with almost 46% of the market), Murata, NXP, Analog Devices, and STMicroelectronics – remain the most widely used. Panasonic and its piezoelectric gyroscopes are an exception.

Yole SystemPlus provides a representative picture of the supply chain through the analysis of 20 MEMS inertial sensors used in safety applications (ADAS, airbag safety systems, and electronic stability control (ESC). OEMs such as Continental are diversifying their sources and working just as well with all the main players. The modules’ teardown reveals different designs based on stand-alone (accelerometer or gyroscope) or combo (up to 5-axis) sensors. With the need for better-quality data, we expect the penetration rate of 6-axis IMUs to increase in the coming years. Companies are currently developing and testing these devices, which will have to meet stringent automotive requirements before being implemented into safety systems. A comparison between the old BOSCH sensor generation and the newest one reveals a packaging evolution from SOIC (Small Outline Integrated Circuit) to BGA (Ball Grid Array) with a 40% reduction in the packaging footprint. SEM cross-sectional images extracted from the components show that a major modification has been made to the capping process. By switching from Glass-Frit to AlGe eutectic wafer bonding, the component area is reduced by up to 30%. As a consequence, the ratio between the sensing area and the MEMS die area has increased. However, this innovative capping technique involves more processing steps (six lithography steps versus three for Glass-Frit) and uses a more expensive raw material, resulting in a cap wafer and bonding process cost 1.5 times more with AlGe.

With regards to navigation applications, Yole SystemPlus highlights that from the panel of 11 MEMS inertial sensors analyzed, most of the module suppliers work with BOSCH, confirming the real dominance of the company in this market segment. Navigation assistance has already made the switch to IMUs which, coupled with Global Positioning System (GPS), allow precise monitoring of the vehicle’s location in real-time. Three different packaging integration strategies have been identified. BOSCH, Senodia, and Epson develop the ASIC, gyroscope, and accelerometer on separate chips. STMicroelectronics uses a technology that covers the MEMS gyroscope cap with a getter film. By doing this, the manufacturer avoids the problem caused by the difference in operating pressure between the gyroscope and the accelerometer while combining both MEMS on the same die. TDK InvenSense uses a monolithic integration approach integrating the MEMS IMU and ASIC on the same die, leaving much less flexibility in design and product evolution. It is worth mentioning that the MEMS inertial sensor market is seeing the arrival of a Chinese player, Senodia, which has established a strong collaboration with X-Fab for its device manufacturing. Senodia products are now in mass production for probable integration in car modules in the near future. With a fairly simple architecture at first glance, cross-sectional analysis reveals that the sensor consists of three wafers: a cavity Si wafer, a SOI (Silicon on Isolator) membrane wafer, and a top cap Si wafer. Compared with the two-Si-wafer structure by BOSCH, Senodia’s design involves a higher manufacturing cost.

Magnetic 2D position sensors

Magnetic sensors allow contactless and, therefore, wear-free measurement of the angle, position, or speed of a car’s moving parts and can be found in the steering angle system, brake and gas pedals, rotor position system, throttle valve, etc. The magnetic sensors for automotive market reached US$1.5 billion in 2022. And with a 4% CAGR22-28, it is expected to reach almost US$1.8 billion in 2028.  Yole SystemPlus focuses on magnetic 2D position sensors for automotive and provides a comparison of 13 devices from the market’s leading suppliers, including Infineon, TDK, Melexis, NXP, ALPS Alpine, AMS OSRAM, Analog Devices, and Sensitec. Although Hall effect technology retains a predominant place, alternative technologies like Anisotropic MagnetoResistance (AMR), Giant MagnetoResistance (GMR), and Tunnel MagnetoResistance (TMR) are getting traction. Featuring high sensitivity, high resolution, and low power consumption, TMR seems to stand out by combining all advantages to attain more reliability and efficiency. However, the design and manufacture of TMR sensors cannot be assigned to just anyone. It demands extensive knowledge and expertise in the magnetic field, which is predominantly possessed by current or former manufacturers of MRAM (Magnetic Random Access Memory) such as Crocus Technology, Infineon and TDK.

Yole SystemPlus will be exhibiting and addressing the topic of MEMS at Sensors Converge (June 20-22, Santa Clara, CA, Booth#432) and MEMS World Summit Europe (June 13-14, Porto, Portugal).

About the authors

Khrystyna Kruk is a Manufacturing & Data Analyst at Yole SystemPlus, part of Yole Group. With strong expertise in Semiconductors, clean rooms & fabrication processes, Khrystyna works in the Semiconductor Devices Department collecting and analyzing data on manufacturing processes, equipment and materials through surveys, interviews, and publication research to improve cost calculation of electronics devices manufacturing.  Prior to System Plus, Khrystyna worked at Assystem (Paris, France), where she was in charge of marketing analyses of International financial institutions for projects in the energy field and international business plan preparations. Khrystyna holds a master’s degree in Nanoscience & Nanotechnology from Ecole Centrale de Lyon (France), a double degree in High Technology and Finance from Taras Shevchenko National University of Kyiv (Ukraine), and an MBA in International Business Management from IAE, University of Grenoble Alpes (France).

Erwan Gapihan, Ph.D, is Principal Technology & Cost Analyst at Yole SystemPlus, part of Yole Group. Erwan has over 15+ years’ experience in R&D centers (IBM, CEA-Grenoble), 200-300mm Production Fabs (Tower Jazz, Crocus Nano Electronics), or start-up (Crocus Technology), where he held R&D, Management, and Director-level positions. He has strong knowledge in Technology Transfers with experience in Materials, Physical & Electrical characterization. His core experience is in Semiconductor Manufacturing, especially in the process integration of Cu damascene interconnects, MRAM, RRAM, IPD and Superconducting Quantum technologies. Erwan holds an engineering degree from INSA-Rennes (France), and a PhD. in the field of MRAM (CEA-Grenoble, France).