Abstract: A scanning system for scanning bar codes attached to wafer cassettes received in a chamber of a wafer processing tool. The system includes a scanner positioned external to the chamber for reading the bar codes and generating signals indicative thereof. Light generated by the scanner passes through an opening in the chamber wall and reflects off one or more reflective or refractive members positioned internal to the chamber, to illuminate the bar code attached to a wafer cassette contained in the chamber. Light reflected from the bar code likewise is bent by the reflective or refractive members and passes through the wall opening where it is sensed by the scanner. The reflective or refractive members are positioned so that the scanner can read bar codes which are not within the line of sight of the scanner through the wall opening.