A brief guide

Annett Fischer

Annett Fischer >


Semiconductors – one way, then another

Semiconductors are chemical substances that have the properties both of electrical conductors and of non-conductors – hence semiconductors. As microchips, they are built into practically every kind of electrical system. They are a key technology of the connected world.

Silicon – the raw material of the connected world

Silicon (Si) is the stuff of high-tech dreams. In the natural world, it is as common as sand on the beach – in fact, sand is mainly made up of silicon dioxide. To get the ultra-pure monocrystalline silicon needed for chip production, oxygen is extracted from the sand in a complex process. One metric ton of sand is enough to make roughly 3,000 wafers measuring 300 millimeters in diameter.

Wafers – the semiconductor world in disc form

In the world of semiconductors, the term “wafer” means a circular disc made of a material such as silicon. In what is known as a drawing process, a round monocrystal – the ingot – is created from extremely hot liquid silicon. The ingot may be 300 millimeters in diameter and more than one meter long. This cylinder is then sawed into discs – the raw wafers. These discs are thinner than a millimeter. In a manufacturing process lasting up to several month, these discs are turned into semiconductor chips.

Semiconductor chips – and what they have to do with skyscrapers

A microchip comprises many superimposed layers, like the stories of a skyscraper. Roughly 30 layers are stacked on top of each other in a microchip. Each of these has a particular function, such as conducting electricity or forming resistors. To create these layers, the wafer has to go through hundreds of process steps. In these steps, additional thin layers are deposited onto the wafer and structured. First, individual layers are deposited on the raw wafer, coated with photoresist, then exposed through a photomask. Only the exposed photoresist hardens, while the coating that has remained soft is removed by an etching solution. The surfaces that have been stripped in this way are now subject to physical processes, as a result of which the material there takes on the required electrical properties. Following that, any remaining photoresist is removed by cleaning. A new layer is now deposited on the wafer layer that has been treated in this way, and the process starts over – with a photomask for the next layer and the associated process. The more layers that are created, the more complex and powerful the chip will be. In this way, active and passive components are created on the wafer. Metal conductor tracks connect them with a circuit. It may take several months for a wafer to pass through all these process stages. All the circuits that have been created in this way are then checked for functionality while still on the wafer. The wafer is then sent to manufacturing partners, who break it up into individual chips and package them in their typical plastic housing. Following a further function test, the microchips are ready to be used in many electronic parts, components, and systems.

MEMS – seeing, feeling, smelling

Rectangular or square, smaller than a pinhead, and between one and four millimeters tall – the tiny MEMS sensors are hugely versatile all-around talents in the connected world. MEMS stands for microelectromechanical systems. They act effectively as sensory organs in a wide range of different applications in vehicles and supply the control units with important information, such as whether the car is spinning on a slippery road surface. Nowadays it is also impossible to imagine consumer and entertainment electronics without MEMS sensors. For example, they transform a simple cellphone into a smartphone that takes sharp photos with no shaking or jittering. MEMS sensors consist primarily of a MEMS element and an ASIC on a tiny circuit board. The whole object is covered by a protective casing.

ASICs – chips with built-in “intelligence”

If MEMS sensors are the sensory organs of the connected world, then application specific integrated circuits (ASICs) are the brains. They process the information from the MEMS sensors and trigger further actions. For example, they deploy a vehicle’s airbags at exactly the right time. Although the silicon chips measure just a few square millimeters, they contain complex circuits, sometimes featuring several millions of individual electronic functions.

Power semiconductors – brimming with strength

These special semiconductor components look after the controlling and switching of high electrical currents and voltages. To manage this, they are equipped with special switching and conducting properties, as the high currents and voltages would destroy ordinary semiconductor components. In electric and hybrid vehicles, for example, they control the energy flow in the power electronics between the battery and the e-motor and ensure that the electricity is used as efficiently as possible.

Cleanrooms – not just clean, but squeaky clean

Semiconductors are made up of extremely fine structures roughly 50 times thinner than a human hair. In the manufacturing rooms for semiconductor production, therefore, it must be ensured that there is absolutely no dust or other contaminating particles present in the ambient air. Even the tiniest of particles can destroy semiconductor components. Therefore, the air is kept clean using special extraction and filtering technology. There are various cleanroom classes. Sensitive chip manufacturing requires the purest: class 1. For work clothing, this means: coverall, gloves, hood, and face mask. And make-up, lipstick, and eyeliner are a no-go.

Yellow light – without the sun

The cleanroom is illuminated with a special yellow light that contains no ultraviolet radiation. This prevents the photoresist-coated wafers from being inadvertently exposed.

Mobility Solutions is the largest Bosch Group business sector. It generated sales of 42.1 billion euros in 2020, and thus contributed 59 percent of total sales from operations. This makes the Bosch Group one of the leading automotive suppliers. The Mobility Solutions business sector pursues a vision of mobility that is safe, sustainable, and exciting, and combines the group’s expertise in the domains of personalization, automation, electrification, and connectivity. For its customers, the outcome is integrated mobility solutions. The business sector’s main areas of activity are injection technology and powertrain peripherals for internal-combustion engines, diverse solutions for powertrain electrification, vehicle safety systems, driver-assistance and automated functions, technology for user-friendly infotainment as well as vehicle-to-vehicle and vehicle-to-infrastructure communication, repair-shop concepts, and technology and services for the automotive aftermarket. Bosch is synonymous with important automotive innovations, such as electronic engine management, the ESP anti-skid system, and common-rail diesel technology.

The Bosch Group is a leading global supplier of technology and services. It employs roughly 395,000 associates worldwide (as of December 31, 2020). The company generated sales of 71.5 billion euros in 2020. Its operations are divided into four business sectors: Mobility Solutions, Industrial Technology, Consumer Goods, and Energy and Building Technology. As a leading IoT provider, Bosch offers innovative solutions for smart homes, Industry 4.0, and connected mobility. Bosch is pursuing a vision of mobility that is sustainable, safe, and exciting. It uses its expertise in sensor technology, software, and services, as well as its own IoT cloud, to offer its customers connected, cross-domain solutions from a single source. The Bosch Group’s strategic objective is to facilitate connected living with products and solutions that either contain artificial intelligence (AI) or have been developed or manufactured with its help. Bosch improves quality of life worldwide with products and services that are innovative and spark enthusiasm. In short, Bosch creates technology that is “Invented for life.” The Bosch Group comprises Robert Bosch GmbH and its roughly 440 subsidiary and regional companies in some 60 countries. Including sales and service partners, Bosch’s global manufacturing, engineering, and sales network covers nearly every country in the world. With its more than 400 locations worldwide, the Bosch Group has been carbon neutral since the first quarter of 2020. The basis for the company’s future growth is its innovative strength. At 129 locations across the globe, Bosch employs some 73,000 associates in research and development, of which nearly 34,000 are software engineers.

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