Still in top shape after around 30 years

© Dirk Wilhelmy

© Dirk Wilhelmy

© Dirk Wilhelmy

© Dirk Wilhelmy

© Dirk Wilhelmy

© Dirk Wilhelmy

© Dirk Wilhelmy

From satellite via car to mobile phone: Modern sensor and communication systems in the high-frequency range play an important role in our everyday life. Products from United Monolithic Semiconductors GmbH (UMS) are used in many areas of telecommunications, vehicle electronics, defense, and aerospace technology. Founded in 1996, UMS is a German-French corporate group of Thales and Airbus Defence and Space with production facilities in Ulm and Villebonne/France. At UMS in Ulm, work is carried out around the clock, seven days a week – the company cannot afford downtime in manufacturing. Therefore, all materials installed in the production building had to be extremely durable, low-maintenance, and long-lasting. When building the Ulm plant in 1989, the decision-makers chose flooring systems from nora systems. Because the rubber floors "Made in Weinheim" are not only exceptionally wear-resistant and easy to maintain. Their electrostatic discharge capability also remains reliably maintained over decades.

Reliable link in the ESD protection chain

The semiconductor components manufactured at UMS in Ulm generate, receive, process, and amplify signals in the microwave range. They are indispensable not only in aerospace technology but also in everyday life across many fields. For example, radar sensors in vehicles ensure that persons and objects in the blind spot of the mirrors are detected, thus preventing accidents. The production building erected in 1989 on Ulmer Eselsberg belongs to Daimler AG, which housed its semiconductor research there. In 1996, these activities were transferred to the German-French joint venture UMS. Since then, the manufacturing building has been leased to UMS. When choosing the flooring for the cleanrooms, the most important criterion for selecting noraplan was the cleanroom compatibility (ISO 5 or better) and the reliable protection of sensitive electronic components against electrostatic discharge. "This aspect is also essential for UMS," emphasizes Raphael Ehrbrecht, Manager Process & Tools 1 and ESD Coordinator at UMS. "We cannot afford to have damaged components arrive at our customers."

Discharge capability remains permanently intact

"The long durability of floors is a very important argument in cleanrooms because replacing the flooring involves enormous effort: systems must be shut down and dismantled from the respective rooms, the floor removed, the adhesive sanded off – all work that cannot be carried out during ongoing operation – we would have to completely halt production for the entire renovation period," Ehrbrecht continues. "We are extremely satisfied with the rubber floors in this regard, as they still fall within the limits defined by DIN EN IEC 61340 even after this long period of use, which is regularly confirmed by measurements and walking tests conducted once a year."

Rubber floors pass all tests

System tests evaluate not only the floor and shoes alone but also the "human-shoe-floor" system. This must function reliably because employees in the cleanroom need to move freely, and grounding via wrist straps or similar is not possible. "We let randomly selected persons walk over the floor with their cleanroom shoes and examine the measurement results," describes Ehrbrecht. "The nora floors are always compliant with standards in this regard." The reason for their excellent long-term performance: Like all nora ESD floors, the one installed at UMS is homogeneous rubber and therefore "volume-conductive." This means that the entire machine-produced floor structure is homogeneously dischargeable and not just locally – unlike systems made with fibers or veins. This also allows for a permanent absence of conductive coatings or so-called ESD waxes on the floor.

Hygienic cleaning with coating-free surfaces

The coating-free nature of nora floors is also a major advantage in terms of cleaning. With their resistant, abrasion-proof surface, they are not only easy to maintain but also provide a permanently high level of cleanliness: "The floors in the cleanroom are lightly mopped several times a day; the focus is mainly on dust binding," explains Ehrbrecht. In hallways and offices outside the cleanroom, cleaning machines are used once a week. "Cleaning works flawlessly, and the floors still look impeccable after about 30 years." Ehrbrecht also considers the safety of the rubber floors a significant benefit: "The surface is slip-resistant and glare-free, helping to prevent falls."

Data and facts

Object: Cleanrooms of United Monolithic Semiconductors GmbH (UMS) Ulm
Client: Daimler AG, Stuttgart, www.daimler.com
Architect: Kohlbecker Gesamtplan GmbH, Gaggenau, www.kohlbecker.de and Richard Meier & Partners Architects LLP, New York/USA, www.richardmeier.com
Products: noraplan® ESD floor, installed area 2,500 m²
Installation: 1989 – 1990
Application area: Cleanroom, offices, corridors