In recent years, tiny components that are barely visible to the naked eye have led to rapid progress in electronics and enabled ever more powerful devices. Printed circuit boards make cell phones, computers, cars and airplanes work. Even in medical technology, such as hearing aids, the tiny components enable the high functionality of the technology in the smallest of spaces. GS Swiss PCB AG, Küssnacht, specializes in the manufacture of miniaturized printed circuit boards and is holding its own in this market with 170 employees against strong Asian competition. The Swiss high-tech company achieves this by guaranteeing the high reliability of its sensitive products and through customized production with short delivery times. To enable the development of sensitive components into even smaller structures, GS Swiss PCB has invested in three new clean rooms for various process steps.
Edgar Camenzind is Deputy Production Manager at GS Swiss PCB and explains the importance of cleanroom technology for the quality of production: “The critical processes in the production of our highly integrated PCBs take place in cleanrooms. Every speck of dust is our enemy and leads to rejects in production.” Production must be completely controlled and without any contamination. This is only possible with cleanroom technology. “In future, we want to improve our ultra-fine structures even further and have therefore built three new cleanrooms for different process steps.”
Three new cleanrooms for controlled processes
The three new systems at GS Swiss PCB were planned, manufactured and installed by long-standing cleanroom partner Schilling Engineering GmbH, based in Wutöschingen and Trasadingen in Switzerland. A major challenge here was the confined space conditions, which required precisely adapted solutions. In order to keep production downtime to a minimum, part of the installation of the clean room systems was also carried out without dismantling the existing production lines. The development steps in PCB production are highly specialized and divided into different areas.
A brand new feature at GS Swiss is its own sputtering system, in which the carrier film is copied. The film serves as the base material for all further processing steps. A 40 m2 clean room system with ISO clean room classes 5 and 6 was installed for the sputtering process. The materials are fed into the Cleanroom via a 1.50 m wide material lock with a double swing door for pallet trucks. At the request of the PCB manufacturer, the cleanroom walls, doors and pass-throughs were fully glazed to allow an unrestricted view into the work area from outside. The extremely tight space conditions for the ceiling plenum of the cleanroom required special planning. Schilling Engineering’s engineers arranged the filter units and ventilation ducting precisely between the on-site pipework to make the best possible use of the confined space. In a further process step, multilayer rigid, rigid-flexible and flexible printed circuit boards are produced. The wafer-thin carrier foils are joined and pressed in several layers. The newly installed 130 m2Cleanroom meets the requirements of ISO cleanroom classes 7 and 8. Production of the multilayers was not suspended during the cleanroom set-up, but postponed until the night to avoid excessive production downtime. The cleanroom system was installed without removing the existing machines, conveyor belts and production line connections from the room. The cleanroom walls were placed in front of the walls and windows of the existing building.
Clean room facilities built around the production lines
Multilayer production is Edgar Camenzind’s area of responsibility. The deputy production manager remembers the challenging time of the construction work: “Building the cleanrooms was quite a challenge. For us and also for the Schilling Engineering team. We were in full production during the conversion.” During the production of the multilayers and in the final photosensitive process, the cleanroom systems were built around the production line, so to speak. “That demanded a lot of flexibility and organization from all of us.” In a final process step, lacquer is applied to the PCBs and multilayers. Here, too, production must not be contaminated by particles due to the low tolerances in micrometer-precise processing. A further 95 m2 Cleanroom ensures safety in the final processing stage.
The materials are printed, exposed, developed and packaged under ISO class 5 conditions. Individual areas are separated from each other with clean room curtains. 25 high-performance filters, which are installed directly above the processes and offer a high air exchange rate of more than 95 times per hour, ensure contamination-free production of the ultra-fine structures. As UV light must not be allowed to reach the sensitive materials during the painting process, special yellow light lighting was installed and the windows and glass doors of the cleanroom were coated with yellow film. Another special feature is the stainless steel wall modules, which make it easier to meet the increased cleaning requirements of photosensitive production. After several months of planning and construction in various stages, all three GS Swiss PCB cleanrooms have been put into operation.
A total of 277 m2 of ceiling modules with LED strip lighting and 58 filter fan units were installed. The modular design of the CleanCell 4.0 cleanroom system provides for an expansion of the cleanroom facilities. The cleanrooms were equipped with the intelligent CR Control control and monitoring system. Schilling Engineering was also responsible for the cleanroom-compatible installation of the personnel airlocks and the final qualification. Edgar Camenzind is pleased that he can now concentrate fully on the demanding production of multilayers again: “The cleanroom project went really well. There were actually several projects with different requirements. Good coordination with the cleanroom company was immensely important. We always had direct access to Ute Schilling, who coordinated the entire project. Short distances, always approachable, a clear advantage.” The deputy production manager is delighted with the smooth installation of the cleanrooms and, above all, with the fact that the safe production of customer-specific circuit boards ensures the functionality of modern hearing aids and therefore a better quality of life.
This article was published: Medicine & Technology 3 / 2021
