Optimization of a minienvironment design using computational fluid dynamics

This paper discusses the use of a CFD (computational fluid dynamics) code for the design and optimization processes of a minienvironment mounted on a wafer process tool. The three-dimensional code was used to predict the air velocity field and pressure distribution in the minienvironment based on a finite volume approach. The geometric model consists of the minienvironment, the tool surface, and the integrated I/O Indexer interfaces. The airflow in the minienvironment (with a conceptual design configuration) was simulated. The results prompted a design change. The new design has a desirable airflow for a more effective minienvironment performance. Particular attention was paid to air recirculation zones that could potentially trap particles generated during the process and to maintaining a positive differential pressure to prevent cross contamination. CFD was shown to be an important step in the design process.