Besides its economic potential to optimize the efficiency of object identification tasks, RFID can also increase the visibility of physical product flows and thus improve the planning of logistics and production processes. The case example of Infineon Technologies in this paper illustrates the benefits of RFID for inbound logistics in wafer fabs. We describe the concept of LotTrack, a real-time identification and localization system that uses active RFID, passive RFID and ultrasound sensors in order to track production lots in the fab's cleanroom. LotTrack combines the efficiency of process automation with the flexibility of manual production and leads to complete transparency in manufacturing scenarios that had previously been hardly controllable. In practical use, the system has led to better machine utilization as well as drastically reduced lead times and fault rates.