Embodiments generally provide an apparatus and method for processing
substrates using a multi-chamber processing system (e.g., a cluster tool)
that has an increased system throughput, increased system reliability,
substrates processed in the cluster tool have a more repeatable wafer
history, and also the cluster tool has a smaller system footprint. In one
embodiment, the cluster tool is adapted to perform a track lithography
process in which a substrate is coated with a photosensitive material, is
then transferred to a stepper/scanner, which exposes the photosensitive
material to some form of radiation to form a pattern in the
photosensitive material, which is then removed in a developing process
completed in the cluster tool. In track lithography type cluster tools,
since the chamber processing times tend to be rather short, and the
number of processing steps required to complete a typical track system
process is large, a significant portion of the time it takes to process a
substrate is taken up by the processes of transferring the substrates in
a cluster tool between the various processing chambers. In one embodiment
of the cluster tool, the cost of ownership is reduced by grouping
substrates together and transferring and processing the substrates in
groups of two or more to improve system throughput, and reduces the
number of moves a robot has to make to transfer a batch of substrates
between the processing chambers, thus reducing wear on the robot and
increasing system reliability. In one aspect of the invention, the
substrate processing sequence and cluster tool are designed so that the
substrate transferring steps performed during the processing sequence are
only made to chambers that will perform the next processing step in the
processing sequence. Embodiments also provide for a method and apparatus
that are used to improve the coater chamber, the developer chamber, the
post exposure bake chamber, the chill chamber, and the bake chamber
process results. Embodiments also provide for a method and apparatus that
are used to increase the reliability of the substrate transfer process to
reduce system down time.