At the heart of the Run-to-Run (R2R) Control Framework is the GCC, the Generic Cell Controller, which serves to support the R2R control algorithms and coordinate control and information flow between the various R2R Control modules.

The GCC has the ability to function in a hybrid environment consisting of multiple networks, controllers, and equipment. It has also been designed to be able to function in a dynamic environment in which facility structure, products, and operations are constantly changing. The GCC is not dependent on hardware, or network base. Its present implementation is highly portable, being able to run on Intel i486, HP PA-RISC, NeXT, and Sun SPARC workstations "without code modification."

There are a number of characteristics which make the GCC an excellent controller for Run-to-Run Control:

• GENERIC. The GCC is generic with respect to software,hardware, communication protocols, and process and equipment being controlled. The generic qualities of the GCC are due to (1) its use of a dynamic database to store and maintain the control scheme, and (2) its modularity and use of the object-oriented technology, which is exploited to the fullest in the current implementation. The GCC is implemented as a suite of three-tiered client/server applications designed to work in a distributed computing environment. Technologies such as dynamic binding, Enterprise Objects Framing (EOF) and Distributed Objects are exploited while maintaining compatibility with CORBA and other industry standards. In order to replace or add a module to the GCC, one only has to develop a GCC module using well documented GCC API.
• MODULAR. The GCC supports the Run-to-Run control algorithm by coordinating control and information flow between the various R2R control modules. This implementation provides for a generalized control model that is not only flexible, maintainable, and portable, but also allows for the easy incorporation of any third-party or commercially-available control module.
• DYNAMIC. Control knowledge is contained in a dynamic database. The database has the capability of being changed "on the fly" allowing the system to learn. This is contrasted with the the compiled code approach, where every change would require a redesign, recording, and debugging phase.
• ROBUST. The GCC supports the complementary utilization of multiple control and optimization algorithms, and uses fuzzy logic to determine the right algorithm among the available candidates to control the process for a particular run, resulting in more complete coverage of the control and optimization space. the current GCC implementation uses the MIT Gradual algorithm. Other algorithms are being incorporated.
• CUTTING EDGE. The GCC design is forward-looking in the direction of total plant automation. Our model of the VLSI manufacturing facility consists of a hierarchical tree of controllers. The GCC is a class of controllers that can be used at the various hierarchical levels throughout the facility.

To see some more information on the statistical facts of the GCC and its current and future status, follow this link.

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