A process representation for manufacturing purposes differs greatly from a description of simulation sequences required to simulate a process flow. Although process simulation tools have been devised to correspond - in more or less detail - to fabrication processes steps, this correspondence usually ends at sharing the same set of variables to describe basic processing conditions such as processing time and temperature.
Beyond this set of common parameters, fabrication equipments and simulation tools require quite different input data. While equipment reads instructions and parameter values for wafer movement, gas flow control, etc., which have no representation in the simulator, the simulator needs a host of additional information concerning numerical and computational aspects of its internal operation, which, in general, cannot be derived from process settings. Nevertheless, they might have some influence on the solutions calculated and have to be calibrated to accurately model a fabrication process step taking place in a given piece of equipment.
Process statements in the flow description specify fabrication process steps in a simulator-independent way. They form a technology-focused vocabulary that is used as common representation for TCAD and manufacturing. To capture all relevant technology information, each step can carry any number of attributes such as the precise type of equipment or additional parameters not available in the basic process step.
Equipment statements address specific pieces of equipment and describe equipment settings and procedures as used on the factory floor. Both process and equipment steps have to be mapped to simulator statements before starting simulation.