After the low-end controllers on the Machine-level control
system and the communication handlers between the
two levels are tested, the Step_LD of the Process-level
control system can be tested. The engineer will first
check if each stage is correctly executed and its
transition condition is met as specified in the AD table
and matrix, and if the required accuracy of each physical
actuation is achieved. The step monitoring and
supervision of the Process-level control system is also
checked, by executing a series of process steps in
addition to the loading step. Ultimately, the Step_LD will
be tested against the loading reliablility (for example,
99.7% of probability of success in loading wafers).