In 2006, Freescale Semiconductor was facing a problem common to companies that must track material through an extended production cycle: the materials — in this case silicon wafers — were proving elusive. At the company's Oak Hill fabrication facility in Austin, TX, hundreds of operators were wasting lots of time looking for wafers, and productivity was suffering.
The company's answer was an innovative application of radio frequency identification (RFID) technology integration that helped make the company's fabrication process much more productive. It also helped earn Freescale Managing Automation's 2008 Progressive Manufacturing High Achiever Award for Data and Integration Mastery.
Semiconductor fabrication is an intricate series of work processes performed in a clean room environment. Transporting the silicon wafers that eventually become semiconductors through hundreds of steps demands not just great care, but also a good deal of efficiency in order to keep cycle times low.
"In the world of semiconductor manufacturing, every step, every keystroke, every second of the operator's day is well accounted for to try and increase the overall operator efficiency," says Ivan Hovey, Freescale's IT development manager.
But, by 2006, Freescale officials knew efficiency was at a tipping point. Throughout each working day, Oak Hill's operators received instructions from the company's manufacturing execution system (MES) to retrieve certain wafers for processing. Once they knew which lot to use, however, they had to find it, which meant scanning what Hovey calls a "bread rack," looking for the carrying cassettes with the correct sticker numbers. The process took more than four minutes, on average.
"They themselves recognized how painful it was to locate the lots that they needed to process," Hovey says of the workers.
The company decided on a solution that would piggyback on the Oak Hill plant's existing infrastructure and deliver better information to the fab's workers. The result was a system of RFID tags that transmitted location data over the factory's beefed-up WiFi network.
Freescale enlisted RFID provider AeroScout, which specializes in WiFi-based systems, to outfit wafer lots with active RFID tags that would identify each lot's location, giving workers a guiding system they hadn't had before. But data alone didn't solve Freescale's woes; the integration of the RFID data into the company's MES system truly brought the ROI home.
"We knew that to be successful, we were going to have to integrate with the MES," says Jennifer Johns, the RFID project lead. "We didn't want to have a separate system that they were going to use to try to find the [location] information."
Freescale's home-built integration between the AeroScout system and the in-house MES, which debuted in 2007, now allows a fab worker looking for the next lot of wafers to search for it in the MES system. The MES signals the RFID tag to identify itself, which it does by rapidly blinking its LED for the worker to see.