APF Fusion Bridges Simulations and RTD for Improved Fab Operation Decisions
Continuous improvement programs (CIP) are a key part of achieving manufacturing excellence in a fab. Through incremental changes, unused manufacturing capacity can be identified, enabling a fab to better respond to unexpected events. However, CIP efforts can also lead to risk and uncertainty caused by the unpredictable nature of changes being made.
Dispatch rule management is often part of CIP efforts, which strive to improve rules to enable better decisions within the fab. The challenge is that rules changes are difficult to test, and thus, may have unintended consequences. Factory simulation software can be used to manage these risks, but the simulation models are often not accurate enough and can be expensive to maintain. In particular, today’s simulation software requires that dispatching rules be manually coded, which is expensive and prone to error.
APF Fusion, the latest addition to Applied Materials’ Advanced Productivity Family (APF) software suite, is designed to solve this problem. A dispatching and capacity analysis solution, APF Fusion provides a bridge between Applied’s AutoSched AP simulation and APF RTD (real-time dispatching) software. (see Figure 1) The APF Fusion solution utilizes the same dispatching rules both in production and in the simulation. Using exactly the same rule in both environments makes rule modeling accuracy much easier to achieve. Furthermore, since the rule is written using the APF formatter, a world-class rule writing environment, the costs and time are reduced.
|Figure 1. APF Fusion—the latest addition to Applied’s Advanced Productivity Family of integrated software tools—is designed to mix rule dispatching with simulation to improve factory productivity. |
The ability to use the same dispatching rules in production and in a simulation provides two main benefits. First, the simulation is more accurate, leading to more precise short-term capacity planning. Second, it is now possible to quantify the effect of proposed rule changes before they are put into production. These two capabilities allow unused manufacturing capacity to be reclaimed and reduce the risk involved in CIP changes.
APF Fusion is based on the observation that most of the processing in a dispatching rule is not part of the actual decision logic embodied in the rule. Instead it is simply data preparation. Because of the complexity of modern Computer Integrated Manufacturing (CIM) systems, about two thirds of a typical dispatching rule is taken up by the extraction of data from CIM systems and the processing of such data in a format that is usable for making a decision. The actual decision logic typically makes up just one-third of the rule.
Inside the simulation, data preparation is not needed since the simulation already has the data close to the format needed for decision making. With APF Fusion, the user can separate the data preparation from the decision making. Additional blocks run only during the simulation that converts the simulation data into the format needed for decision making. Because the simulation data is much simpler than production data, typically only a few additional function blocks are needed. The end result is a single rule that can execute in both production and simulation, with the appropriate blocks automatically executed based on the environment.
APF Fusion has demonstrated value at advanced 200mm semiconductor fabs in North America and Europe. In one fab, it reduced the time to integrate an RTD rule into simulation from over six months to just one week. Furthermore, after this integration was completed, the APF Fusion customer was able to use the simulation to validate the effects on KPIs of five different dispatching parameters in one week.
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