Freescale Semiconductor, a privately held manufacturer of embedded integrated circuits (ICs) for the automotive, consumer, industrial, networking and wireless markets, is using a Wi-Fi-based active RFID system to help boost productivity at one of its factories for fabricating silicon wafers.
The chip maker is employing active tags and related hardware and software from AeroScout, a San Mateo, Calif., provider of real-time location systems (RTLS). The AeroScout system includes active 2.4 GHz RFID tags; exciters, which activate the tags, causing them to transmit their identification numbers; and the AeroScout Engine, designed to calculate tag locations by processing data from the tags and various Wi-Fi access points. The system also incorporates AeroScout’s MobileView software, which can portray location information on a map, in a table or in a report.
Headquartered in Austin, Texas, Freescale reported sales of about $6.4 billion in 2006 and carries out design, research and development, manufacturing or sales operations in more than 30 countries. Prior to adopting the AeroScout system, the company had been looking for a way to manage its lots—the containers it uses to transport 25 silicon wafers at a time through a maze of processes and machinery designed to turn a blank wafer into a multitude of IC chips. Machine operators had to manually search for the appropriate lot, as indicated by Freescale’s real-time dispatch system and identified by the lot number written on the front of the lots stored on racks throughout the factory. Locating the lots typically added several minutes to each individual process, decreasing the company’s overall productivity.
“The challenge for us is that our newest factories were built in the 1990s, so these are not new fabs,” explains Glaston Ford, Freescale’s company spokesperson. “Because the wafers move through different process steps in an iterative process—there is a lot of back and forth as you layer patterns on the circuits—fabrication is not an ‘A, then B, then C’ process, and it is time-consuming. We have been looking for ways to increase productivity at these older fabs that aren’t as automated.”
About a year ago, Freescale began working with AeroScout to develop an RFID system able to help it more easily locate lots. Equally important was the need for a Wi-Fi-enabled system, since Freescale had implemented Wi-Fi networks on the plant floor to network the laptops used by engineers. “Since we were already using Wi-Fi,” Ford explains, “we knew there’d be no interference with the other equipment.” Freescale and AeroScout worked on the design and implementation for several months, then took the RTLS system live six months ago.
Now, at the start of production, an active AeroScout RFID tag, encoded with a unique ID number, associated in a back-end system to a specific lot number, dates and other information, is attached to the front of a lot filled with 25 silicon wafers. . As production processes get underway, machine operators follow the instructions on the real-time dispatch system, accessible on a computer terminal adjacent to the machinery.
The RTLS system automatically feeds location data to the real-time dispatch system. Thus, in addition to supplying the operator with production instructions, the dispatch system also provides location information, including a map revealing a specific lot’s location and rack in the factory. The operator can then click an icon to activate a flashing light on the lot’s RFID tag. Using the mapped directions and the flashing light, the operator can more easily locate the lot.
“What the AeroScout implementation has allowed us to do is speed up and add a significant amount of automation to what is still a very manual process,” Ford says. “It has taken the process of locating a lot from several minutes down to a minute or less.” Though Ford will not reveal the extent to which the factory’s productivity has increased, he says there has been a “substantial productivity improvement.” Upon locating a lot, an operator picks it up and brings it to the machinery to perform the requisite operation. The real-time dispatch system then provides further instructions regarding where to move that lot, and where to retrieve a new lot to begin the process once more.
The RTLS system has been so beneficial, Ford says, that Freescale is now brainstorming to come up with other ways to take advantage of the system. “There are tools that the maintenance guys use to work on processes,” he notes. “We could use RFID to help locate and track these tools.”