A clean affair: Robot-assisted wafer storage
A company that specializes in supplying the automation needs of the semiconductor industry has designed an impressive concept for the interim storage of wafers under cleanroom conditions. Within this innovative system, a St?ubli cleanroom robot performs intricate handling tasks.
The dimensions of the semiconductors on the surface of a silicon wafer are typically measured in nanometers. Under these circumstances, it is clear that any foreign particle, no matter how small, can impair the function of the microchip. That is why the 100 or so individual steps of production take place in a cleanroom environment. When the wafers have to be stored temporarily, they must likewise be kept under cleanroom conditions. This is where the CubeStocker from Fabmatics comes in. At the heart of this innovative system is a St?ubli Super Cleanroom TX2-90XL mounted on a dual-axis gantry which handles storage and retrieval with smooth efficiency and no contamination.
Fabmatics is fully familiar with the purity requirements in semiconductor manufacturing. The Dresden-based automation company specializes in the transport, storage and handling of highly sensitive silicon wafers in semiconductor production. The focus here is on precision, the elimination of particulates, and 100% reliability. These criteria were also paramount in the development of the new CubeStocker storage solution.
Intermediate buffer/storage system for test wafers
The CubeStocker is a fully automated storage system for the carriers in which wafers (maximum capacity 25) are transported and stored. One CubeStocker holds 200 carriers. A conveyor system running along the cleanroom ceiling automatically feeds the carriers into and out of the individual storage locations in the stocker unit.
Depending on the application, the cell serves as an intermediate buffer in production or as a magazine for the test wafers used for the regular measurement, inspection, adjustment and calibration of the equipment in semiconductor production.
The special feature of the CubeStocker deployed here is that it operates within its own ISO 3 cleanroom atmosphere. The wafers are thus temporarily stored in absolutely clean conditions before the next processing step or between test cycles, without any risk of contamination.?
“Supercleaner” robot with two additional axes
The handling of the wafer carriers is performed by a St?ubli six-axis cleanroom robot. To ensure that the robot can access all positions, it is mounted on a rigid dual-axis gantry. The additional axes allow it to stack carriers at floor level as well as reach up to conveyor level above the storage locations. This space-saving solution enables the precision robot to pick up the carriers from the conveyor system and stack or retrieve them.
The Fabmatics design team opted for a St?ubli TX2-90XL with 1,450mm reach in the Super Cleanroom (SCR) specification, which qualifies it for use in ISO Class 2 cleanroom environments.
In addition to the Super Cleanroom spec, which only St?ubli can supply in this design, the other criterion guiding Fabmatics’ decision was the extremely smooth running of St?ubli robots. This is due not only to their proprietary high-precision drive technology, but also to the superior performance of the St?ubli CS9 robot controller .
Why are such enormous demands placed on the robot’s performance? Martin D?umler, Head of Product Development at Fabmatics explains: “Quite simply, wafers are fragile, and the value of the 25 wafers in a carrier is somewhere between 100,000 euros and the cost of a family home. Consequently, risk- and vibration-free handling as well as precise positioning in the sub-millimeter range must be ensured under all circumstances.”
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The decision-makers at Fabmatics were already satisfied that St?ubli robots met this requirement profile. But as Managing Director Dr. Roland Giesen explains, “We also use St?ubli robots in many other automation solutions. They meet our requirements for cleanliness, reliability and precision to the highest degree and enjoy a high level of acceptance among our customers. That is why we also chose a high-performance Super Cleanroom robot from St?ubli for the CubeStocker. In addition, we appreciate the collaborative and professional relationship based on mutual trust that has been in place for several decades and has been a vital factor in our growth.”
Successful start followed by expansion into a product family
In CubeStocker, Fabmatics has developed a new type of system that has been successful right from the start. Martin D?umler: “The combination of a compact footprint, good integration into processes, and a built-in cleanroom atmosphere is unique. We have already completed multiple units, and one particular semiconductor manufacturer has ordered several of them.”
Development continues towards a product family. “We are currently working on a ‘Test Wafer Center’,” says D?umler. “This will add an area for single-wafer handling to the CubeStocker and allow users to assemble their wafer set for inspection cycles – fully automated, ultra-precise and under cleanroom conditions.” And of course, carrier handling in the Test Wafer Center will be performed by a St?ubli Super Cleanroom TX2-90XL .
Text by: Industrie Kommunikation H?gel
About St?ubli Robotics
St?ubli Robotics is a leading global player in robotics, consistently delivering engineering as effective and reliable as our service and support. A complete solutions provider for digitally networked production, St?ubli offers a broad range of 4- and 6-axis robots including robotic arms designed specifically for sensitive environments, autonomous mobile robots, driver-less transport systems (AGVs) and cobots for human-robot collaboration.
About Fabmatics
Dresden-based Fabmatics GmbH is an experienced specialist in the automation of material flows and handling processes in the semiconductor industry and other highly technical production environments. Founded in 1991, the company with its approximately 250 employees have been successfully implementing customer-specific automation projects in the semiconductor industry for more than 30 years.
The company offers a modular product range of hardware and software for the automation of handling, transport, and storage processes as well as solutions for product identification and localization. Systems such as mobile robots, robotic cells, cleanroom storage, RFID components and much more ensure more efficient, rapid, and reliable production processes in semiconductor factories. The portfolio is supplemented by consulting and development services from the company’s own R&D department for the realization of client-specific solutions with a unique depth of customization and maximum functional reliability.
Fabmatics GmbH thus has the expertise to offer comprehensive solutions in the field of material flow automation under cleanroom conditions – all from a single source.
Thank you for featuring our #CubeStocker! It's always a pleasure to develop such a highly complex solution, which must meet the manifold requirements of the #semiconductor industry, with a great partner like ST?UBLI Robotics. ?? ??