"Effect of Design and Choice of Materials on the Integrity of a Gas Delivery System," Proceedings of Workshop on Gas Distribution Systems, SEMICON West 96, San Francisco CA, July 1996.
Abstract: The design aspects of a gas delivery system, including the choice of materials and components, have a significant impact on the performance of the gas delivery system and on the quality of the processing environment. The main contaminants arising from gas delivery systems supplying bulk or non-reactive gases are moisture and particles. Particle shedding from components in a gas delivery system and excessive moisture or trace gas impurities increases the number of defect densities and subsequently decreases the process yield. For reactive gas delivery, the generation of reaction by-products, particles due to the reaction between the gas and the gas distribution system itself is an important contamination issue. It has been shown that the contaminating environment within the gas delivery system can adversely affect the purity of the process gases delivered to the tool. This paper illustrates the important parameters to be considered in the design of a gas distribution system, downstream of the point-of-use purifier in a semiconductor fab. Data from case studies is used in certain cases to quantify the contamination effects caused by poor choice of materials and non-optimal design, on the quality of the gases delivered to the process tool. Design consideration such as purge capability for process lines, process line isolation, inappropriate component configuration and dead spaces are addressed. Additionally, the compatibility between materials and process gases, the choice of materials based on contaminant specifications and the benefits of clean room manufacturing techniques are demonstrated. |
