A system for processing semiconductor wafers has process units on a deck of a
frame.
The process units and the deck have precision locating features, such as tapered
pins, for precisely positioning the process units on the deck. Process units can
be removed and replacement process units installed on the deck, without the need
for recalibrating the load/unload robot. This reduces the time needed to replace
process units and restart processing operations. Liquid chemical consumption during
processing is reduced by drawing unused liquid out of supply lines and pumping
it back to storage.
