Cluster Tools are complex production plants. Those are typically a combination of several process modules and a handling system. The challenge is to integrate individual, partly different, module control systems in the central control system as well as to generate and administrate flexible process sequences. Those functions will be realized by the Cluster Tool Controller. The Cluster Tool Controller (CTC) has to integrate process and transport module controls (PMC and TMC), undertake scheduling and dispatching for the overall process, manage recipes and provide the communication to the MES (Host interface). Motivation and reasons for the use of cluster tools are:
- Integration of several production steps in one plant and therewith a reduction of total proccessing time
- Increasing the process reliability by reducing interruptions in the production process
- Lowering of pollution and interferences (e.g. by doing the handling in vacuum)
- Engineering and programming Cluster Tool Controller faces several challenges as integration of process modules from different suppliers with heterogeneous interfaces, the logistic with one transport system and a combination of modules, the collision free transport of substrates and of course a time optimized scheduling
According to the plant structure and the process requirements the material can be processed in sequential and parallel mode. Parallel flows are based on intelligent scheduling algorithms which consider alternative modules and different flow recipes for substrates. The focus of scheduling optimization is always to increase the utilization of the Cluster.