Power Semiconductors Weekly+ Vol. 05
Bosch is Gunning for a Bigger Slice of the Automotive Semiconductor Business
The global automotive semiconductor market is forecast to reach $73.2 billion by 2028, with a compound annual growth rate of 11.5 percent from its $38.1 billion level in 2021. That’s according to a new report from Vantage Market Research.
Bosch aims to participate in this booming market, with a 3 billion Euro investment in its semiconductor division, which has recently opened a new 300-mm silicon wafer fab in Dresden. “Microelectronics is the future and is vital to the success of all areas of Bosch business,” observed Dr. Stefan Hartung, chairman of the Bosch board of management during Bosch Tech Day 2022. “We’re gearing up for continued growth in demand for semiconductors – also for the benefit of our customers,” Hartung said. “For us, these miniature components mean big business.”
Bosch says it is targeting technologies such as systems-on-a-chip and radar sensors, aiming to make them smaller, smarter, and cheaper to produce. Recognizing the risk of lengthy supply chains, Bosch says it is supporting an effort to double Europe’s slice of global semiconductor production from 10 to 20 percent by the end of the decade. “Europe can and must capitalize on its own strengths in the semiconductor industry,” Hartung said.
A key factory in automotive semiconductor shortages that have plagued OEMs is the industry’s use of larger-scale 40-to-200-nanometer semiconductor lithography than is employed by the latest computers and consumer electronics. Bosch’s facilities will produce chips at this larger scale, according to Hartung. “More than ever, the goal must be to produce chips for the specific needs of European industry,” he said. “And that means not only chips at the bottom end of the nanoscale.”
The company is expanding another semiconductor center in Reutlingen, spending 400 million Euros on it by 2025. This will expand its manufacturing capacity and convert of existing factory space into new clean-room space. A new 3,600-square-meter extension in Reutlingen, which will contribute to the facility’s clean room expansion from today’s 35,000 square meters to more than 44,000 square meters by the end of 2025.
The Dresden 300-mm fab boasts an array of technical features designed to put it on the cutting edge of chip manufacturing. This includes the connection of all the roughly 100 machines and lines in the 10,000-square-meter cleanroom so they can communicate with each other and with the building’s infrastructure.
That required 300 kilometers (186 miles) of data lines carrying as many as 1,000 data channels for each machine in real time and relaying it to a server in the plant.
In total, the production data generated is equivalent to 500 pages of text per second, equaling more than 42 million pages per day. Within this avalanche of data is information on the status of where each individual wafer is in the production process, where it is going next, and when it will arrive. The wafers are transported from machine to machine by a completely automatic system featuring individual pods known as FOUPs (front opening unified pods). Each FOUP can transport as many as 25 wafers, so the factory doesn’t need any manual transportation of wafers at all.
That mountain of data can’t be monitored manually, so that is automated too, with an AI evaluating the data generated in the wafer fab to detect even the tiniest anomalies in products. These anomalies are visible on the wafer surface in the form of specific error patterns known as signatures. Their causes are immediately analyzed and deviations from the process corrected without delay, even before they can affect the reliability of the product.
Bosch says that this is the key to further improving the manufacturing processes and semiconductor quality, as well as to achieving a high level of process stability. It also means that semiconductor products can go into full-scale production quickly.
Additionally, the AI’s algorithm predicts when a piece of manufacturing machinery or a robot needs maintenance or adjustment, so such work is not done according to a rigid schedule, but only when it is needed before any problems arise.
One way the plant is kept running smoothly is by modeling its operations with a digital twin. During construction, all parts of the factory and all relevant construction data relating to the plant were recorded digitally and visualized in a three-dimensional model.
The resulting digital twin comprises roughly half a million 3D objects, including buildings and infrastructure, supply and disposal systems, cable ducts and ventilation systems, and machinery and manufacturing lines. This allows Bosch to simulate both process optimization plans and renovation work without intervening in ongoing operations.
It isn’t only the machinery that is augmented with connected data. The plant’s workers employ augmented reality using smart AR glasses and tablets to see digital content superimposed on the real environment. One AR app developed by Bosch displays energy data from the wafer fab in a virtual model of the building to optimize the efficiency of the manufacturing machinery. Another app uses glasses to help with construction planning and another is planned to aid remote maintenance of the plant’s machinery.
Meanwhile, the Reutlingen plant is gearing up to make silicon carbide semiconductors for high-voltage EV power electronics. Bosch has been mass-producing silicon carbide chips since the end of 2021. Because silicon carbide can contribute to a hard-won 6 percent increase in driving range this market is seeing annual rates of 30 percent or more, according to the company.
Bosch is investigating even more exotic technology for EV applications. “We’re also looking into the development of chips based on gallium nitride for electromobility applications,” Hartung said. “These chips are already found in laptop and smartphone chargers.” To make these chips suitable for power electronics in EVS they will have to become more robust and able to withstand substantially higher voltages of up to 1,200 volts.
“Challenges like these are all part of the job for Bosch engineers,” Hartung added. “Our strength is that we’ve been familiar with microelectronics for a long time – and we know our way around cars just as well.”
This is true, as Bosch has been active in automotive electronics for more than 60 years. The Bosch semiconductor plant in Reutlingen, for example, has been producing chips based on 150- and 200-millimeter wafers for the past 50 years. With the recent investments, it seems like both of Bosch’s semiconductor sites are well-positioned for the next 50 years.
Original – DesignNews
Toshiba Releases 2.5A Output Smart Gate Driver Photocoupler for IGBT and MOSFET Control and Power Protection in Industrial Applications
Toshiba Electronics Europe GmbH (“Toshiba”) has launched a ±2.5A output smart gate driver photocoupler able to control IGBTs and MOSFETs, reliably protecting power devices from over-current. The device is suited to a wide range of applications including inverters, AC servo drives, photovoltaic (PV) inverters and uninterruptible power supplies (UPSs)
The TLP5212 features a new totem pole output with two N-channel MOSFETs, to ensure compatibility with specifications widely used in applications such as industrial equipment. In addition, the new photocoupler incorporates protection functions such as desaturation detection, active Miller clamp, UVLO and FAULT output, eliminating the need for several external circuits. This reduces system costs for fault detection and protection as well as saving space and design effort. Moreover, by incorporating Toshiba’s own reliable and powerful infrared LED, it can be used in severe thermal environments.
The TLP5212 can sink or source up to ±2.5A via its totem pole output. With its propagation delay of just 250ns (max.) and propagation delay skew of ±150ns, the device is suited to use in high-speed applications. The operating temperature range (Ta) is -40°C to +110°C, ensuring suitability for industrial and renewable energy use.
Housed in a small SO16L package, the new photocoupler measures just 10.3mm x 10.0mm x 2.3mm, allowing it to be used where space is tight. Even with this compact package, it features a minimum creepage distance of 8mm, allowing it to be used for applications requiring high levels of safety isolation and insulation (BVs = 5000Vrms).
The TLP5212 requires a signal on the input side to resume from protection. A further device, the TLP5222, which resumes automatically after a specified time, is in development.
Original – Toshiba
Vincotech’s New Three-level NPC Module
Get the most out of your solar inverter with Vincotech’s new three-level NPC module! The 450 A, 600 A flowNPC 2 module is the path to go for higher output power. The chipset is optimized to maximize the power density, increase efficiency and enhance thermal performance. The integrated on-board capacitors enable higher DC-Link voltages and smaller passive components by reducing up to 40 % the voltage overshoot.
Samples of the new flowNPC 2 are available through usual channels.
- Higher power density maximizes the ROI
- Up to 40 % lower voltage overshoot enables higher DC Link voltage
- Optimized chip combination for Solar applications
- Solder or Press-fit pins and pre-applied TIM to help reduce production cost
Original – Vincotech
Exploring Automated Single-Wafer Ashing of Compound Semiconductors
Ashing, in which the light–sensitive coating known as photoresist is removed and cleaned from an etched wafer, is one of the most important and frequently performed steps in chip fabrication. In this step, photoresist organics are “burned off” using a processing tool in which monatomic plasma is created by exposing oxygen or fluorine gas at low pressure to high–power radio waves. Previously, wafer ashing was largely done using batch–processing techniques to achieve the required throughput.
However, unlike silicon semiconductors, in which wafers are mass–produced in a standard 300–mm size, compound semiconductors are made of silicon carbide, gallium nitride, gallium arsenide, and sapphire, which can vary from 100 to 200 mm. When this is the case, significantly better uniformity of photoresist removal is required, which means better temperature and process controls. As a result, most compound semiconductor wafer manufacturers require automated, single-wafer–processing tools capable of fast ashing rates and high production levels.
Today, semiconductor manufacturers are increasingly looking for a single-wafer–ashing solution for both high–temperature photoresist removal and precision descum.
MICROWAVE PLASMA ASHING
For 50 years, most plasma tools have used radio frequency (RF) for stripping photoresists. RF plasma etches the surface through a physical process that essentially bombards the surface with plasma in a specific direction.
In the past, you could simply increase the DC bias and remove everything, but RF plasma is not as selective in attacking photoresist. Also, when the photoresist is removed, the underlying layers of the wafer may be sensitive and could be damaged with RF.
Today, microwave–based plasma tools produce a very high concentration of chemically active species and low ion bombardment energy, ensuring both a fast ash rate and a damage–free plasma cleaning.
Microwave tends to be quicker and produces higher ash rates than RF.
TARGETED PHOTORESIST REMOVAL USING OXYGEN
Advanced microwave–based plasma ashing systems from manufacturers like PVA TePla often utilize oxygen as the primary process gas. The oxygen ashes the wafers very selectively and attacks only the photoresist, leaving the rest of the wafer untouched.
Unfortunately, using a pure oxygen process is not always compatible with all types of wafer surfaces; some require a combination of gases.
There can be other materials on or within the photoresist that cannot be stripped away completely with just oxygen alone. To resolve this issue, we may add some fluorine chemistry, usually CF4, mixed with the oxygen.
Because of the trend of using different materials in wafers, some metals are oxidized easily during the process, which is not desirable. Both hydrogen and oxygen gases at low pressure can be used in such circumstances.
Adding hydrogen will prevent the metals from oxidizing while the oxygen removes the photoresist. This is one thing we control very tightly during wafer ashing, and it requires excellent temperature uniformity to accomplish this task.
Working with MEMS devices requires the removal of SU–8 or similar epoxy–based negative photoresists. A challenge with negative photoresists is that parts exposed to UV become polymerized, while the remainder of the film remains soluble and can be washed away. Moreover, the chemical stability of SU–8 photoresist can make it difficult to remove.
Removing SU–8 must be performed at lower temperatures. You need to be below 100˚C, and in certain cases below 50˚C. More flexibility in the chemistry is also required, including potentially the use of fluorine and excellent control of the temperatures. All of this is much easier to accomplish with single–wafer processing.
Customers may have a photoresist on a metal surface deposited between two metal surfaces, requiring the removal of the photoresist from the side of the wafer. Due to its isotropic etch property, oxygen–based microwave plasma ashers can remove the photoresist in between the metal plates, unlike RF–based systems.
EASE OF SINGLE–WAFER AUTOMATION
In manually loaded systems, the asher has a pull–out door, where the wafers lie on the heating or cooling plane mounted on the entry door of the chamber. In automated systems, wafers are increasingly loaded into the chamber utilizing robotic handling.
Today, customers want to reduce all human factors as chips become more advanced. This requires automatic handling and loading using robotics and full control by a host computer. In some cases, the operator only needs to place the cassette onto the load port, which will start automatically.
PVA TePla, for example, has designed its GIGAfab–A plasma system to be configurable for 200– or 300–mm wafers and a cluster tool with up to three process modules called the GIGAfab Modular. Both systems use open cassette, as well as front opening or standard mechanical load stations. Wafer processing is thermoelectrically controlled from RT to 250˚C. A unique planar microwave plasma source provides high ash rates over a wide temperature range.
With wafers becoming thinner, more reliable automated single-wafer–processing equipment handles fragile wafers.
“Trying to handle the wafers physically without the use of robots can end poorly,” said Ryan Blaik of PVA TePla in California.
Single–wafer processing also provides better temperature controls.
“With batch processing, microwave radiation must heat all the wafers in a quartz boat, and the temperature can fluctuate during processing,” Blaik said. “For a single-wafer–processing system, wafers are brought into the chamber only after preheating, allowing a constant temperature to be maintained during processing.”
In single–wafer processing, a descum process can be accomplished using the same tool. The primary difference between the two processes is the temperature the wafer is exposed to while in the plasma chamber.
For descum, we want a low ash rate and good uniformity and process control. Because we are only targeting removal of residues, an ashing recipe at very high temperatures will not work. It is easier to accomplish using single–wafer ashing using a microwave–based plasma system.
As more semiconductor device fabrication continues to ramp up globally to meet an insatiable demand for chips, the need for control, efficiency, and configurable solutions for wafer ashing will continue as the chips themselves increase in complexity and decrease in size. Automated, single–wafer microwave plasma systems provide chip fabricators with targeted and configurable ashing that meets the needs of an increasing array of wafer types.
Original – EE Times
Technology and Cost Comparison of Seven Automotive Power Modules from: Hitachi, StarPower, Vitesco Technologies, STMicroelectronics, Denso, and Wolfspeed
The new environmental regulations to reduce average CO2 emissions and automotive trends play in favor of greater vehicle electrification and faster deployment of electric vehicles/hybrid electric vehicles (EV/HEVs).
Power modules are a key element for this transition. According to Yole Intelligence, the power module market for xEV represented a market value of $807 million in 2020 and will reach $3.59 billion by 2026.
Innovations in power module design are continuously being developed for enhanced performance. We can find them in all power module structures, from the baseplate and substrate assembly down to the die attach and through the electrical connection.
In this dynamic context of the power modules packaging market, Yole SystemPlus provides a deep comparative review of seven automotive power modules (including three SiC power modules), with a focus on packaging level. The modules are from Hitachi, StarPower, Vitesco Technologies, STMicroelectronics, DENSO, and Wolfspeed.
This report provides, in its introductory section, exhaustive graphs concerning all the trends and design solutions observed in all analyzed modules by Yole SystemPlus in its previous reports. For the seven modules analyzed in this report, we highlight differences in module design and technology parameters and their impact on production cost.
Also provided are optical images for the module’s package view, package opening, and cross-section, as well as SEM cross-section images for some of the analyzed modules.
Cost simulations are performed for all of the modules’ parts (die and module level). Process and cost are only detailed at the module level – substrate: DBC/AMB/plate assembly process and module assembly process. The dies’ process is not detailed; just the final die cost is imported in the module’s BOM cost.
Finally, this report provides exhaustive physical, technological, and manufacturing cost comparisons of the analyzed modules.
Original – Yole Group
Warwick University Commissions New ESPEC Test Chamber
Power Electronics Applications and Technology in Energy Research at Warwick university have commissioned and installed a new ESPEC ARS060680 fast rate environmental test chamber from Unitemp.
The Power electronics team (PEATER) in the School of Engineering at Warwick is led by Professor Phil Mawby.
The new chamber is part of a suite of equipment that’s been funded through Driving the Electric Revolution (DER) as part of its main centers of expertise initiative. The chamber will support state of the art research and development in Wide-Bandgap semiconductor technologies under the area of Power Electronics Machines and Drives (PEMD).
This new tranche of equipment augments a well-established cleanroom for dice processing as well as an epitaxy capability for Silicon Carbide.
The ARS 060680 ultra-fast rate environmental stress chamber has a temperature and humidity range of +10 to +95°C/10 to 98 %rh with a refresh rate of 15K/min and will be used to stress the semiconductors and Invertors specifically for automotive applications.
Commenting Professor Mawby said, “We wanted a chamber that provided us with maximum flexibility, allowing us to undertake a multitude of tests including high and low temperature storage, thermal cycling and temperature and humidity stress testing.”
The emphasis at PEATER is to develop a facility for reliability and testing of assemble power devices, modules and assemblies. Industry already has access to these facilities and PEATER are providing both the expertise and facilities to evaluate new ideas, assemblies, and integrations for use in the fast-growing automotive sector.
PEATER at Warwick carries out work in electrical energy conversion, from the very small power (mW) levels to very high-power levels (MW). This technology centers on the developments in semiconductor switching devices.
The developments in MOSFET ((Metal Oxide Semiconductor Field Effect Transistor) and IGBT (insulated-gate bipolar transistor) technologies have paved the way for new applications such as hybrid vehicles, electric aircraft, electric ship propulsion, wind turbines as well as the revolution in mobile phone and computing devices, where energy management is critical to all these applications.
Original – NewElectronics
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