Fully automated FOSB bagging with cleanroom robots

Packing wafers into FOSBs (front opening shipping boxes) is a complex process that must take place under cleanroom conditions. In order to remove the human factor, a Bavarian company has developed a fully automated solution that is second to none. In it, two Stäubli cleanroom robots are charged with end-to-end handling of the boxes.

In the far south of Bavaria, in the picturesque town of Burgkirchen, a small but promising specialized machine manufacturer set up shop in 2006. Its innovative automation solutions quickly attracted international attention. With its sophisticated systems, the young cts GmbH succeeded in gaining a foothold in some of the most discerning sectors, including automotive, electronics, semiconductors and life science, all the while building up the relevant expertise. After years of strong growth, cts GmbH now has more than 350 employees across multiple sites. The company continues to thrive on its innovative strength, as evidenced by the new AutoBagging Tool (ABT).

Alfred Pammer, senior board member at cts, describes the purpose and nature of the system: “The ABT is a complex, fully automated robot cell equipped with two cleanroom-compatible Stäubli six-axis robots which handle the complete bag-in-bag packaging of FOSB containers with their valuable loads of wafers. This pioneering solution replaces the traditional bagging process, which is still carried out manually in some cases, and offers distinct advantages in terms of process reliability, efficiency and quality.” In order to meet the ever-increasing demand for its proprietary solution, cts recently set up a completely new, state-of-the-art production facility.

In contrast, manual packaging of FOSBs, each weighing up to 10 kilograms, is a very physically demanding task. The employee must first check that the wafers are correctly stacked in their box, then check that the various attachments have been correctly fitted to the FOSB, and round out the exacting process with inner and outer bagging, all the while operating under cleanroom conditions and in cumbersome cleanroom overalls.

Fully automatic instead of manual

A quick look at the complete compact cell, designed and built by cts, in which all components such as packaging stations, inspection chambers, robots, vision systems, printers and the like are integrated, shows just how rapidly, easily and efficiently the fully automatic packaging is carried out with the two Stäubli TX2-160 cleanroom robots. Before the FOSBs, typically loaded with 25 wafers, begin their journey through the system’s 15 stations, they are identified by RFID, as is standard in the semiconductor industry. The requisite parameters are queried by the host system via the SECS/GEM interface. All the necessary process steps are then carried out on the basis of this information.

The containers loaded with wafers arrive by means of an overhead hoist transport (OHT) system and are fed into the system via an infeed conveyor. The first step is the “cross slot check,” which takes place at an inspection station, where the correct positioning of all wafers in the box is checked.

The first Stäubli six-axis robot picks up the FOSB and presents it to a vision system that checks the correct positioning of the parts attached to the box. The next step is labeling and subsequent quality control of the label. The TX2-160 performs both process steps by holding the container securely in its gripper and presenting it to the labeling and image processing station. To keep cycle times short, the TX2-160 performs all movements with high dynamics and precision.

A complex process: Bag-in-bag packaging     

Now it’s time for the first packaging process involving the inner bag. The six-axis machine deposits the container at a fully automated station, where the inner bag is packaged and sealed. The next process steps are folding and gluing the flap and leak-testing the vacuum packaging.

This inspection station is also where Robot 2 takes over from Robot 1. The first of the two TX2-160s deposits the box for inspection, and the second six-axis robot picks it up once the check has been completed. Robot 2 then takes on all handling of the box for insertion into the outer bag. The same steps involved in the packaging process for the inner bag must be carried out, including further labeling and a quality check of the label. Finally, the robot places the fully packaged and inspected FOSB on the outfeed conveyor.

“The system not only ensures a significant increase in quality and process reliability, but also greatly increases output,” says Alfred Pammer. “The ABT AutoBagging Tool can achieve a throughput of up to 8,000 FOSBs per month.” Another huge advantage of the system is that it can handle a variety of FOSB formats with different attachments. Thanks to the flexibility of the Stäubli robots and the gripper technology developed in-house by cts, the ABT can bag almost all variants without any time-consuming changeover processes – a USP that is appreciated by customers all over the world.

Even the requisite compliance with ISO 6 cleanroom standards poses no challenge for the two Stäubli robots – they already comply with this classification in the standard version. Alfred Pammer: “We always choose Stäubli robots for our semiconductor systems, as they are virtually the benchmark for cleanroom environments and are also extremely precise and reliable. These systems run around the clock, mainly in Asia and in other parts of the world, so we cannot afford any malfunctions let alone complete breakdowns.”