A scheduling tool for processing large-area flexible electronics

The scheduling of state-of-the-art equipment for manufacturing microelectronic circuitry on flexible substrates is considered. Three major processing steps are the following: vacuum deposition, photolithography, and photoresist development. Customers of this facility have different needs and thus have different processing time requirements, different due-dates, etc. The n-job, three machine flowshop problem, while relatively trivial for some performance measures, can be NP-complete for others (e.g., tardiness-based criteria). A scheduling tool to be used in conjunction with the Lekin ® software created at NYU is being developed. Data are entered for the scheduling instance, namely, the number of jobs, processing times, due-dates, weights, if applicable, and the performance measure of interest. Lekin-based files will then be created from the data and used as inputs into the Lekin software. Intelligence, in the form of heuristics, is being embedded into the system. For example, if the performance measure is makespan and it is determined that the maximum time on the photoresist tool is no greater than the minimum time on the other tools, then a special application of Johnson's Algorithm will identify the optimal permutation schedule to process the jobs. The primary output of the system is the recommended schedule of the jobs, replete with Gantt chart.