Wafer and reticle handling within semiconductor manufacturing
environment is very critical and plays a very important role in the entire
manufacturing process. In a typical 300 mm semiconductor manufacturing Fab
wafers are transported via means of a FOUP1,
similarly reticles are kept in special reticle pods 2.
In a semiconductor fab these reticle pods and FOUPs are transported via OHT3
, smaller fabs also use AGV4
to bring these pods and FOUPs to the “Litho” tool and track. However within
ASML, an original equipment manufacturer of lithography equipment FOUPs and
reticle pods are handled manually by people, mostly via means of a PGV5.
Since 2011 it has become way of working that tool runners (humans), execute the
transport and placing of FOUPs and reticle pods on the machines. In current
ASML cleanroom environment tool runners (humans) transport FOUPs and Reticles
via means of PGV .This process leads to productivity losses. If no PGV is
available reticles are transported without a PGV, in this case 2 operators are
required to transport one reticle pod.
At times reticles are damaged at times due to manual handling. 8 out of
46 reticles got lost (unknown location), due to missing RFID tag reader and traceability.
Large amount of money is continuously invested in training tool runners how to
handle FOUPs and Reticles. Under current ” AS-IS” situation material movements
(FOUPs and Reticle pods) is done by hand, on an average more than 200 km
walking per day is done in 5 shifts by almost twenty tool runners. Also the
current PGV’s occupy a lot of space in cleanroom and are expensive to buy. In
order to meet the current demand of transporting FOUPs and reticle pods more
PGV’s need to be bought. PGV’s also introduce contamination via wheels inside
cabins. Specifically new NXE systems are very prone to contamination.
1 Front open unified pod
square shaped container made from plastic which is used to transport reticle
throughout semiconductor fab
Overhead transport hoist
Automated guided vehicle
Person guided vehicle