Semiconductors already have a significant impact on our daily lives. They can be found in every cell phone and microcontrollers are also of central importance to the automotive industry - think of keywords such as autonomous driving, intelligent battery management or connectivity in general. The German Electrical and Electronic Manufacturers' Association (ZVEI) estimates that semiconductors worth 474 billion dollars were sold worldwide in 2018 - an increase of 15% compared to the previous year. And growth will continue to develop dynamically in the future, not least because demand is constantly increasing in areas such as consumer electronics, but also in the industrial environment.

The production of semiconductors requires dozens of production steps - the linking of the individual steps is still done manually today.

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The majority of semiconductors and microchips are based on the chemical element silicon. Silicon itself is not particularly suitable as an electrical conductor, but its electrical properties can be precisely adjusted by doping. In semiconductor production, the doped silicon is processed in the form of wafers. These wafers, produced in various sizes and with a thickness of less than one millimeter, are stored in special plastic cassettes during production. While the processing of the wafers is already largely automated - a total of well over 100 process steps are necessary for the production of microchips! -However, the transport from one processing machine to the next and the loading of the processing machines is still largely manual.

Why is it that automated transport solutions and thus a more efficient linking of the individual processing stations have hardly been found in practice to date? On the one hand, this is due to the challenging environment; on the other hand, it is due to the difficult framework conditions. For example, the production of highly sensitive semiconductors is subject to the highest requirements in terms of climate, cleanliness and functionality in the manufacturing process. These are only possible in a clean room. In addition to air purity, which must be ensured with complex and energy-intensive air conditioning systems and multi-stage filtering, special equipment and tools as well as the appropriate work technology are required in order to comply with the specified cleanliness classes. Another challenge is the high sensitivity of the wafers. Due to their nature, the components are very susceptible to mechanical damage, for example from vibrations or pressure.

Theoretically, it would be possible to completely demolish and rebuild the production facilities for the automated transportation of the cassettes and rely on static transport solutions such as linear gantries. However, manufacturers have invested heavily in their existing production facilities. In reality, this scenario is therefore not an alternative for cost reasons alone. The same applies to a large-scale conversion. An automated solution for linking the individual production steps would therefore have to be able to be integrated into an existing production environment, combine the most important characteristics of man and machine and at the same time minimize the challenges that human intervention entails. After all, despite cleanroom equipment, there is always a risk of particles being introduced. Furthermore, even the most careful manual handling does not guarantee loss-free production. Given the high cost of a wafer, the costs of such errors quickly add up to enormous sums.

The requirements for automated handling

In addition to the necessary sensitivity to be able to perform the handling tasks with the required sensitivity, a modular mobile solution is ideally required that can be integrated into an existing production environment and allows the wafer cassettes to be transported autonomously from one process step to the next, independently loading and unloading the respective machines. Another challenge is that in the existing production environment, wafer processing is rarely linear - the individual processing machines are not necessarily directly next to each other, but often far apart.