A Full Factory Transient Simulation Model for the Analysis of Expected Performance in a Transition Period
Intel's Fab-18 is based in Israel, and has transitioned from producing 0.18-micron logic devices to producing 90 nM flash products. During this transition period, the factory has de-ramped in volume of logic while ramping-up flash. AutoSched AP software was utilized for the development of a transient simulation model of the Fab's behavior during this period. It is the first attempt, at Intel, to utilize a full factory simulation in order to analyze and support decisions that pertain to a transient period of parallel de-ramp and ramp-up of technologies. Unlike typical simulation models for the analysis of factory performance and behavior in steady-state, the transient model poses several modeling challenges and requires major adjustments in dealing with these challenges. In this paper, we discuss those aspects. The benefits and contribution of such a model to decision making and the improvement of factory performance are also presented
Semiconductor manufacturing material handling systems: integrating dynamic fab capacity and automation models for 300mm semiconductor manufacturing
Semiconductor fabrication facilities (fabs) continue to expand in both complexity and volume. As a result, integrated models are required to determine even high level impacts to key success indicators. In order to gain insight into how the components of a factory impact performance metrics, Intel uses an integrated discrete-event simulation modeling approach. Two models, one fab capacity and one automation model, are used. This paper discusses the methodology for building and integrating both models, and the results from using this method.Both the fab capacity and automation models have a variety of input parameters that are required to drive the simulation. In addition, each model produces output parameters, some of which are used as inputs to the other model. An iterative feedback technique eventually results in a convergence on the appropriate data to feed the fab capacity model, which enables Intel to determine the impact of automation on 300mm wafer semiconductor manufacturing, and predict factory performance. Intel's approach provides the capability to use the models in stand-alone mode for specific fab-only or automation-only analyses, and also to take on any number of analyses via model communication. Intel continues to search for new applications for these merged models to answer strategic operational questions.
Turbulent boundary layer wall‐pressure fluctuations downstream from an abrupt change in surface roughness
Spectra of wall‐pressure fluctuations beneath a turbulent boundary layer have been investigated immediately downstream from an abrupt change in surface roughness, from slightly rough to very rough. Over the measurable frequency band (400 Hz to 7 kHz), the spectra in the first 150 mm scale on wall variables. This indicates that the motions responsible for the pressure fluctuations measured in this region are very close to the wall. Farther downstream this scaling procedure breaks down. It is suggested that the initially thin internal layer behaves independently of the flow external to it until it has grown appreciably and only then interacts with the outer boundary layer. It was found that, for all frequencies measured, the dimensional spectral level decreases initially then rises to a maximum at 250 mm from the roughness change before decreasing once more. The position of the maximum is close to where the internal layer ceases to have a distinct edge.