ACES

The automotive industry is changing. Our vehicles are getting electrified, connected and automated. As this trend is accelerating, it’s having an impact on how semiconductor devices, including MEMS sensors, are designed and qualified for automotive. As automotive semiconductor designers carefully consider product definition, product validation, and long-term reliability, MEMS sensor suppliers are responding to new opportunities created by electrified and automated vehicles by developing inertial measurement units (IMUs) for automated driving as well as battery pressure monitoring sensors for Li-ion EV batteries. The most complex MEMS device of all The automotive MEMS IMU is probably the most complex MEMS device that will be used inside a vehicle. This type of IMU is a System-in-Package (SiP) comprised of multiple gyroscope and accelerometer sensing elements plus a signal processing ASIC, integrated into one package that creates an inertial sensor able to measure up to six degrees of freedom (6DoF): yaw, roll and pitch for rotational movements, and lateral, longitudinal and vertical acceleration for linear movements. Degrees of freedom in a vehicle For vehicles with Level 3 autonomy and above (per SAE definition), the IMU is mandatory for taking over the trajectory control of the vehicle in case other sensors, such as the camera, radar or LiDAR, become impaired. Should such a failure occur, the IMU will function as a guidance sensor to bring the car to a safe stop within a short period of time and distance. The IMU is also used to control the regular movement of the car while driving in automated mode. While IMU technology already exists for aerospace applications, there are significant challenges to adapting it for automotive. The automotive IMU requires high performance at costs that are compatible with the automotive industry. Because automotive life cycles are long, MEMS sensor suppliers must produce the device in high volume for an extended period of time. They must also guarantee the sensor’s performance and reliability over a 10- to 15-year lifetime with no maintenance or recalibration of the sensor required. Only a few MEMS suppliers have the capability and willingness to embark on this kind of journey. Electrification is creating new applications for MEMS sensors The conversion from internal combustion engines to electrified propulsion is going to affect the powertrain MEMS market. For example, pressure sensors used in engine management for air pressure and fuel pressure will simply go away with electrification. However, the use of large Li-ion batteries in electrified vehicles has created a new application for MEMS sensors. One of the known risks of Li-ion batteries is the small probability for a battery cell to go into a thermal runaway situation that will lead to a fire. The press has reported multiple cases of EV batteries catching fire. Thermal runway effects When it comes to thermal runaway events, every second counts. Detecting the event as early as possible enables the vehicle safety system to take all necessary measures to warn occupants of an imminent fire and activate timely countermeasures (e.g., trigger fire extinguisher and call fire brigade) to mitigate the impact of the fire. Published studies have shown that measuring the pressure inside the battery pack is a good indication that a thermal runaway is starting. The outgassing of a battery cell, plus a sudden rise in temperature, will increase pressure inside the battery pack, which will generate a pressure pulse. To detect such a pressure pulse, a MEMS pressure sensor must permanently measure the pressure inside the pack. It must also report to the battery management system any suspicious change in pressure, independent of atmospheric pressure changes. It’s important to keep this kind of sensor on all the time to detect any pressure anomaly in the system, even when the vehicle is completely off. NXP has developed a pressure sensor to specifically address this new safety application in EVs, and several automotive manufacturers are already using this solution. NXP battery pressure management sensor The quest for zero defects While the automotive industry is targeting zero fatalities as its ultimate goal, the semiconductor industry and module suppliers are targeting zero defects for each and every semiconductor device. For safety-critical automotive MEMS sensors complying with the Automotive Electronics Council (AEC) Q100 qualification for semiconductors, it’s necessary but clearly not sufficient to guarantee a zero defects production launch and long-term reliability of the device. To boost the reliability and robustness of automotive sensors, NXP has developed Above and Beyond (AaB), a new methodology that studies advanced reliability and robustness well ahead of the device’s qualification and production release. Based on risk-mitigation analysis, AaB consist of extensive testing, such as test-to-fail, corner lot testing, and new use-case testing combined with advanced statistics, all of which help NXP understand how these different parameters interact with each other. As sensor suppliers must integrate AaB into their project planning, it does add time and cost to the project. The upside is that this early investment pays off as long as weaknesses in the device can be detected and corrected before a production launch. Field failures, on the other hand, can lead to unplanned redesign and requalification of a device. Worst-case, they can lead to a recall campaign that costs a huge amount of money. We’re systematically using the AaB methodology at NXP for safety-critical MEMS sensors because its potential benefits far outweigh its costs. For more information about NXP MEMS sensors, register for the upcoming webinar series, MEMS to Market: Ingredients for Success, where NXP will discuss The Growing Importance of MEMS Reliability (May 5, 2021). Register by March 10 to watch all the webinars LIVE. Each webinar will also be available to watch on-demand at your convenience. Contact the author via LinkedIn or learn more about NXP sensors. About the Author With nearly 30 years of experience in the field of automotive and MEMS sensors, Marc Osajda is responsible for European automotive MEMS sensors business development activities at NXP Semiconductors. Osajda holds an engineering degree in mechanics and electronics from the French Ecole Nationale Superieure d’Arts et Métiers (ENSAM). NXP Semiconductors is an active member of MEMS Sensors Industry Group®(MSIG), a SEMI technology community that connects the MEMS and sensors supply network in established and emerging markets to enable members to grow and prosper. Visit us today.

In the first part of this double feature, we looked at the automotive industry’s transition toward a mobility ecosystem and the shifting business model perspective from selling vehicles to miles. At the core of these changing dynamics are four trends represented by the acronym ACES: Autonomous, Connected, Electric, and Shared mobility. Each of these trends is largely enabled by microelectronics through computer processors, sensor units, and communication architectures. Part 2 of this series explores the business opportunities at the transition from automotive to mobility, and the specific role SEMI can play as a natural bridge between the two ecosystems.Electronics and Software as Drivers for Automotive InnovationThe ACES trends represent an acceleration of the shift in automotive from the industry’s traditionally strong focus on mechanics and hardware toward electronics and software. This transition to electronics and software as drivers for automotive innovation already started in the 1970s with electronic fuel injection, anti-lock brakes, trip computers, and many other attributes that are now considered standard features. As a result, there are now hardly any automotive systems that are not computer-controlled. A vehicle without power windows and locks, electronic climate control, or MEMS-reliant airbags are basically unimaginable in many markets.As shown in the graphic[1] depicting the electronics share of total vehicle cost, the numbers paint a clear picture of the continued growth of electronics over time, with a 44% share today expected to grow to 50% by 2030. McKinsey Company estimates the automotive software and electrical/electronic (E/E) components markets combined will grow at a 7% CAGR from USD 238 billion in 2020 to US$469 billion by 2030[2].The assumption of continued and sustained growth presents a promising outlook for semiconductor and sensor content in vehicles over the next decade, which is particularly strong in the electrification space. Hybrid electric vehicles (HEVs) already contain $900 worth of semiconductor content, and battery-based electric vehicles (EVs) contain $1,000 worth of semiconductors – much higher than the average of approximately $450 of content in conventional vehicles[2]. Other business opportunities in the mid-term (3-5 years) include software, battery technology, infrastructure (charging stations, other hardware components, etc.), as well as vehicle-to-vehicle (V2V) and vehicle-to-environment (V2X) communication. These technologies also demonstrate how the industry’s business focus is expanding beyond the confinement of an individual vehicle to increasingly contemplating the evolving ecosystem around it, resulting in real mobility solutions. Image credit: Continental AG This creates significant opportunities for a large number of SEMI members in the semiconductors and sensors business by connecting them with new customers and partners in the automotive and mobility supply chains, primarily vehicle manufacturers and Tier 1 suppliers, and together realizing new business in new automotive applications such as: Autonomy, including ADAS (GPUs, LiDAR, radar, camera, accelerometers...) Connectivity (link to outside infrastructure and in-cabin devices, roadside units...) Electrification (power electronics, battery monitoring, H2 detection in fuel-cell...) Sharing (customizable vehicle interior, trackable mobility devices such as scooters...) In-cabin experience (media systems, displays, VR/AR, occupant detection...) Vehicle architecture (flex-ray, automotive ethernet, diagnostics, smart parts...) Safety and security (HW/SW firewall, parts authentication, upgradability...) In these partnerships, the vehicle manufacturers and component suppliers clearly benefit from leveraging semiconductor capabilities including: Device and system reliability/robustness/quality (“Zero Defect”), which creates opportunities for new SEMI Standards (e.g. wafer-to-device/system traceability) New design architectures for added functionality, safety and security New packaging solutions (automotive OEMs are already participating in the Heterogeneous Integration Roadmap, seeking to collaborate with device manufactures and Original Semiconductor Assembly Test (OSAT) companies to reduce costs and differentiate on automotive-grade solutions Sensors and imaging (cameras) SEMI Smart Mobility Initiative – Connecting Mobility and ElectronicsSEMI launched its Smart Mobility Initiative in 2018 based on the mandate of providing “SEMI members with access to new business opportunities and collaborative platforms in the automotive electronics supply chain.” The initiative is currently focused on synchronizing the automotive and microelectronics supply chains for automotive electronics innovation – in particular semiconductor devices, sensors, and related products manufactured for this space and sold to vehicle OEMs and Tier 1s. To facilitate closer dialogue among stakeholders from this combined ecosystem, SEMI formed the Global Automotive Advisory Council (GAAC) which now has five regional chapters and represents dozens of companies. Collectively, GAAC members discuss and act on a wide range of topics, from Silicon Carbide (SiC) standardization to new design architectures and closing the OEM requirement gap.While continuing to build on the strong automotive foundation, SEMI’s Smart Mobility Initiative is now expanding its reach and scope of activities to broader mobility themes, such as infrastructure and battery technology and Smart City, to infuse SEMI member communities and the GAAC with new stakeholders and new ideas. These are exciting times!Please contact Bettina Weiss, Chief of Staff at SEMI, at [email protected] for further information about SEMI’s Smart Mobility Initiative, the Global Automotive Advisory Council, and how SEMI can help your organization navigate electronics in the automotive industry to drive innovation in the mobility space.[1] see graphic, created with data from NXP / Freescale[2] Source: McKinsey Company, 2019Microelectronics Power the Future of Mobility – Part 1: Autonomous, Connected, Electric and SharedBettina Weiss is Chief of Staff and Global Smart Mobility Lead at SEMI. Sven Beiker is Smart Mobility Consultant at SEMI.