New integrated manufacturing system boosts fab productivity
The Web interface
Modulight s system has been built around a single relational database, which operates on a standard multiprocessor IBM server running Microsoft SQL Server. The production equipment is directly connected to the database (figure 1), and primary access to the system is realized via an integrated Web-based user interface. Some of the specific elements of the access part have been realized by developing stand-alone programs with a graphical user interface using industry-standard software development tools such as Labview and Visual Studio. All of these systems communicate with the database and store all data and parameters in the database itself.
The use of a Web interface makes the system independent of operation systems and it can therefore be used from any PC or hand-held device that has a standard Web browser and a network connection. Most of the system s functions are also designed to work well with the small screen of a Compaq IPAQ portable hand-held device. This has allowed paper-based process notepads to be completely replaced, resulting in lower costs, improved efficiency and increased process monitoring accuracy.
Web access also makes it significantly easier to allow wider access to employees (and eventually to other interested parties) via properly designed extranets. Engineers with secure connections can also access the sys-tem from home, allowing fab engineers to work remotely for perhaps the first time in the industry s history.
The Web interface does not need any special client-side software, so updating it can happen solely at the server side, without disturbance to the users. Also, version control of the user interface is simple and the introduction of upgrades that do not interfere with production to the production system is uncomplicated. Upgrades simply appear to users the next time they access the upgraded functionality or resource.
The platform and development tools have allowed Modulight to focus on the system itself rather than the practical implementation. We have found it very easy and cost effective to rapidly improve the system based on the requirements specified by technical personnel.
These days, when outsourcing is in and internal development is out, one might wonder whether the benefits of developing a custom-made system match the efforts required. But when the project is periodically analyzed, combining customer feedback, resources spent and the improvement in operations, the conclusion reached is that the development of the system is an essential part of improving operations when compared with a normal software development program.
A system for every business sector
When a process technician starts working and connects to the database, the system suggests a suitable process step to be performed. This suggestion is based on the competence of the technician, the availability of equipment and the priority level of the various processes in progress. Once the technician has accepted the process step, the database gives instructions for performing that step, i.e. what equipment and input parameters should be used and any process-specific instructions given by the engineers. While running the process step, the processing/quality control equipment and/or the technician feed data to the database. When one process step is complete, the database suggests which step to perform next.
The automatic production-control feature significantly reduces the resources needed for production management, and ensures that production capacity is used in the most effective way. The automatic allocation of process steps not only allows a reduction in the time spent by production engineers in guiding process technicians, but also enables much more complex and efficient logic to be used in workflow management. As listed above, a number of different production parameters can be taken into account when deciding the process order.
One example is maintaining worker competency. The system can be defined to ensure that each operator repeats all the process steps for which they are qualified at least once every two months, ensuring that process technicians remain cross-trained. However, if at the same time we want to choose those individuals with the best track records for high-priority processes, we must apply rather complex logic. This example shows how the completeness of the manufacturing database system can effectively support the company s human-resources process by ensuring the continuous development of personnel. This increases productivity and the ability for rapid change management down to the production floor.
Some advantages, such as assigning each process step individually, might only improve efficiency in a small-company environment, but we believe that significant economies of scale also exist. Indeed, some of the benefits will only appear in larger fabs. Due to the holistic approach required to achieve such benefits as rigorous traceability, interactivity in decision making and future support for all activities, the basic data structure needs to be very robust and complete. This means that all data must be parameterized if possible, even if the present business model or operations do not necessarily require it. In developing the system we adopted this philosophy, and are now receiving some payback. For example, developing the new functionality requested by users is usually just a matter of adding some logic, parameters or making a new database query. We have found the system easy to integrate with conventional MS Office applications and have produced complex reports in a matter of hours or days.
