For the time being it is not possible to perform process and device
simulation for a complete integrated circuit. However, we are able to
build a representative model of an integrated circuit and its
fabrication process based upon the capabilities of the simulation
tools discussed above. This model focuses the investigation on
dominant processing steps and selects those devices which have the
most impact on the performance of the resulting integrated
circuit. Relying on the simulation tools which have been sketched in
Section 2.1 and Section 2.2, we can build a
model of an IC fabrication technology as depicted in
Figure 2.5. Based upon a process recipe and a set of
lithography masks, we use a process model to manufacture each
device category of interest. In the following these devices are
electrically characterized which finally delivers their electrical
parameters.
Thus we obtain a model of an IC fabrication technology which allows to derive characteristics of the integrated circuits from the process recipe and several sets of lithography masks. As far as the accuracy of this model is sufficient -- which mainly depends on the quality of the involved TCAD tools -- a process engineer is able to use this model during the development of a fabrication process. It can be employed at an early stage of the development in order to evaluate several technology options. This allows for the elimination of some processing variants without any need for pre-production fabrication runs, and thus helps reducing development costs of a technology as well as it shortens the development cycle. Although this model is somehow restricted or idealized, it is of significant value since it is a substitute for the real fabrication process and, therefore, it can be used to characterize and optimize the technology.