German Semiconductor Maker Tracks Production With RFID, Ultrasound

Semiconductor production is a complex process that can include up to 500 steps per wafer lot on hundreds of different pieces of production machinery. Some semiconductor factories are fully automated (see Ultimate Control: RFID-Enabled Manufacturing). Infineon's process, however, still includes such manual tasks as the transport of lot boxes among production bays. By automatically tracking each lot box, the system provides Infineon with a more comprehensive overview of production and capacity, while helping it track those machines that are free and those that are still in use. This allows the company to more effectively react to rush orders and other unexpected events. In addition, processing errors are reduced, thanks to the step-by-step instructions now available to workers on the DisTag displays. Before the LotTrack system was implemented, production instructions and tracking were accomplished using pen and paper.

Ultrasound technology provides a more accurate and stable system for tracking the lot boxes than RFID alone, particularly because Infineon's production environment contains a lot of metal, which can interfere with an RFID tags' radio waves. "By adding ultrasonic time-of-flight measuring, the system provides very accurate and robust location information," says Dierkes.

Infineon had to work closely with Intellion to ensure the LotTrack system didn't impact the clean room—the sterile environment necessary to produce semiconductors, says Hanspeter Fischer, a principal for computer integrated manufacturing at Infineon. "Antennas had to be adapted to the clean room," he explains. "The air flow is important since particles of dust can harm a semiconductor."

The company uses several thousand DisTags in three different LotTrack implementations. The system was installed at Infineon's factory in Villach, Austria, in early 2004; its plant in Regensburg, Germany, in late 2004; and its Kulim, Malaysia, factory in 2006.

Fischer says the company received a return on its investment in the RFID applications within about one year of implementing them. He has declined to provide details at this time, but says Infineon is considering implementing another RFID application: using the tags already sewn into the operators' suits to track their cleaning process.