New 300-Mm Wafer Fab Is Key to Bosch’s Chip Future

The new Dresden plant and R&D center spearhead thrust into GaN, MEMS sensors and FDSOI technologies.

Bosch's 300-mm silicon wafers can require up to 500 steps to manufacture. (Bosch)

A new semiconductor plant is the single largest investment made by Robert Bosch AG in the 122-year-old company’s history. The facility, in Dresden, Germany, is welcome news to automakers focused on building regional electronics production in the wake of supply shortages and bottlenecks. It’s the latest move in Bosch’s strategy to be a major player in the global microchip industry.

Bosch will begin producing MEMS sensors on 300-mm wafers by 2026 at Dresden. (Bosch)

Bosch claims that the new Dresden plant, which began construction in 2017, is the first 300-mm (11.8-in.) wafer production facility to be built in Europe since 1999. Its construction was in step with the European Chips Act announced in February 2022. One of the aims of the Act is to double Europe’s share of global semiconductor production from 10% to 20% by 2030.

A 300-mm chip contains thousands of identical semiconductor devices. Producing a semiconductor involves transferring an integrated layout in a three-dimensional structure to silicon. The process needs repeating up to 27 times and can involve around 500 process steps, according to Bosch engineers. This can take several months, depending on the complexity of the required circuitry.

R&D center focus

Bosch already has invested €1B in the Dresden facility, which was part-funded by the IPCEI (Important Project of Common European Interest) special subsidy. The plant currently employs 350 and staffing will increase to 400 by the end of 2022 and to 700 by the time the plant is completed. The new chip plant is one of two Bosch production facilities in Germany. The other, at Reutlingen near Stuttgart, has produced semiconductors for more than 50 years. Reutlingen produces semiconductors on 150-mm (5.9 in.)- and 200-mm (7.87 in.)- diameter silicon wafers.

A new European funding program, IPCEI 2, is in progress. Within the framework of IPCEI 2, Bosch plans to invest €3B in semiconductor technology and systems by 2026.

This will involve an investment of more than €170 million in the construction of two new development centers at Reutlingen and Dresden, with work at Dresden due to begin in 2023. Dresden will be home to a new development center for both semiconductors and microelectro-mechanical system (MEMS) sensors.

Bosch also plans to produce the MEMS sensors on 300-mm wafers; production is scheduled to start in 2026. Over the coming year, Bosch intends to spend a further €250 million in expanding the clean-room facility at Dresden.

GaN research

Power electronics are key to the needs of electromobility, and Bosch already has been able to extend the range of electric vehicles by 6% through using silicon-carbide (SiC) chips, the company claims. Bosch expects the market for these chips to grow by an average of 30% annually throughout this decade. This has triggered a hunt for chips that offer greater efficiency and reduced cost.

For this, Bosch has begun research into gallium nitride (GaN)-based chips, which already are used in smartphone and laptop chargers. The higher voltages needed for EV charging, up to 1,200 volts, mean that more research is necessary before GaN chips would be production-ready for these applications.

According to Dr Stefan Hartung, chairman of the board of management of Robert Bosch GmbH, “All in all, chips’ share of a car’s total value will quadruple over the course of the decade – from just under €200 to more than €800.”

Bosch recently demonstrated some of its semiconductor applications to a small group of reporters, including SAE Media, at Dresden. Products included a redesigned EV charging cable. European models normally are supplied with two separate cables, one for charging from a European standard 230-V domestic power socket and the other equipped with a Type 2 connector to charge from either a 7-kW AC wall box domestic charger or 11-kW or 22-kW three-phase charger.

Bosch has redesigned the cable so that one cable serves all needs. This has involved integrating the control electronics to regulate the charging in the Type 2 connector at the vehicle end. At the other end, temperature control and a residual-current device are integrated in the connector. This means that the control box usually integrated in the 230-V domestic charging cable can be eliminated, reducing weight by around 40%.

By equipping the other end of the cable with an interchangeable domestic plug or Type 2 connector, the vehicle can be charged from a domestic socket, AC wallbox or AC three-phase supply.

Bosch has been making semiconductors for 50 years and continues to expand its product range. (Bosch)

Other technologies on display included an Audi equipped with all-round sensors for assisted and automated driving. This included a camera and front and corner radar sensors. Technologies include using AI to ensure that the camera system can recognize objects and their positions. Bosch also is developing long-range lidar.

The company also displayed its pre-integrated systems solutions in its advanced driving module (ADM) rolling chassis, designed as a platform for EV development. Individual systems for drive, steering, and braking are integrated into a single harmonized and flexible system.

Simplified interfaces and a consistent software architecture reduce complexity and ensure optimized communication between components. This modular approach allows OEMs to integrate the ADM with their requirements. The rolling-chassis prototype was built as part of an engineering alliance with Benteler, a chassis and body systems Tier 1 supplier.

Big boost in capacity

Perhaps it’s not a surprise that although Bosch needs new machinery to increase its semiconductor production, the shortage of semiconductors also is affecting the supply of that machinery. “It’s a huge point – the drying out of the supply chain and on the other hand, the huge capacity need which was then also generated by [COVID-19],” noted Patrick Leinenbach, senior VP for Manufacturing Semiconductor Supply Chain operations for Bosch. “Now we are all looking first to serve our customers, to ensure that our customers are safe. Huge teams are working on it for our company, to look where to take the products.”

Bosch chairman of the board Dr. Stefan Hartung expects semiconductor share of a new vehicle’s value to quadruple this decade. (Bosch)

On the other hand, he said, the company is building up “a huge increase” in its own wafer-fabrication capacity. “This would not heal the whole semiconductor worldwide crisis,” he said, “but it can heal some missed semiconductor components we see in the industries. The Dresden plant is giving us such a huge opportunity to fill up our stocks again.”

Although SiC chips have helped to extend EV range, the material presents its own challenges. “The raw material is different. If you’re looking for silicon, you have to speak monolith, which is then sliced down in wafers,” Leinenbach said. “It’s not working for silicon carbide.”

This limits the size of wafers that can be produced from the material. Bosch currently can make 150-mm SiC wafers: “You can buy 200-mm wafers at the moment, but the quality is not so good,” he stated. “Therefore, it will take time also to adjust the processes to make them better.”

Gallium nitride offers an alternative material, particularly for power management in charging systems. But as Leinenbach explained, “Silicon carbide gives us the possibility to go back to silicon and then scale this up on 300-mm. So, there are advantages on the electrical coefficients and the things from silicon carbide, in comparison to the gallium nitride. But the gallium nitride can be produced in 300-mm. So, it’s let the market decide what they want."

FDSOI is the future

Bosch research also is continuing into MEMS sensors. “For example, if you have several sensors, they have different pressure conditions on the inside, so you have then two sensors,” Leinenbach explained. “Using new processes that we have developed in recent years, you can put them close together in the same production process, by some process that’s in-between.” This approach saves significant quantities of bonding material, he added.

Automated driving presents opportunities for new developments in semiconductors. “If you look for the actual radar systems, which are then used, they are using the so-called 22FDSOI process,” Leinenbach observed. Fully Depleted Silicon on Insulator (FDSOI) can provide a way of continuing to develop faster and more efficient processors even as they have become smaller.

“This is different from the processes we have, which is then giving some opportunities in a 360-degree radar system” for MEMS sensors. Engineers are looking to use them for automated driving in applications such as radar sensors. “We are trying to develop our products with innovation which can then be used later,” Leinenbach said.