The wafer transfer device has a first unit with a plurality of first slots for receiving a first group of semiconductor wafers and {HEAD ~ a second unit} with {TAIL ~ a plurality} of slots for receiving a second group of semiconductor wafers 
with
The wafer transfer device has a first unit with a plurality of first slots for receiving a first group of semiconductor wafers and { HEAD ~ a second unit } with { TAIL ~ a plurality } of slots for receiving a second group of semiconductor wafers
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH