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2.3 Technology Characterization

The fabrication process of an integrated circuit is an extremely complicated procedure including a huge number of input variables and also a quite large number of circuit characteristics. An integrated circuit is fabricated by several dozens of processing steps, each of which including a couple of processing parameters. The resulting circuits are built up by several categories of microelectronic devices characterized by a couple of device parameters each.

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.
% latex2html id marker 1624\centering\includegraphics{fig/circu...
... categories
that play a significant role in an integrated circuit.}

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.

next up previous contents
Next: 2.3.1 Statistical Analysis Up: 2. Technology Computer Aided Previous: 2.2.2 Interconnect Analysis
Rudi Strasser