Among the components shown in Figure 4.1, process simulation
plays an outstanding role with respect to tool integration for the
large variety of available tools on the one hand and for the
need of arbitrarily changing the order in which tools are invoked
on the other hand.
Moreover, whereas device simulation,
device characterization
, and
circuit simulation transform their respective inputs to outputs of
entirely different domains, process simulation is domain-invariant
inasmuch as process simulation tools produce output that again serves
as input for other process simulation tools.
More precisely, a device simulator reads a model of the wafer structure
and writes numerical values for electrical quantities;
a diffusion simulator reads a wafer model and writes a wafer model.