A stage with controller electronics nestled inside was a key in fielding a metrology station compact enough to fit in a small footprint.
Integrated metrology systems by Nanometrics Inc. had to scan 300-mm wafers quickly to look for defects in films, but could only take up a minimum of space in clean rooms. A MAX 3000 controller from Agile Systems was a natural candidate for controlling the motion of wafer scanning electronics because it fit in a space 3 5 2 in. It took the place of an external box the size of a large PC chassis that was used in previous generations. For the Nanometrics controller Agile devised a special daughterboard which carried extra I/O and sin/cos high-resolution encoders to work with the direct-drive stage. The motors can completely spin a 300-mm wafer in 400 msec and make a 7-in. move in 400-msec hitting a top speed of 21 ips with submicron accuracy. The only external cables to the controller are a power cable and a FireWire connection which also carries machine vision video.