Overall Equipment Efficiency is the measure of the portion of time that semiconductor device manufacturing equipment is actually making semiconductors. Keeping this number high keeps the cost of semiconductors low, eventually providing low cost, high performance computers and televisions to the consumer. Because the line width of semiconductor devices is approaching 0.25 μm, there is a requirement to remove smaller particles from the process fluids. Tighter Teflon ? PTFE filters are used to purify the aggressive acids, bases, and oxidizers used the clean and etch semiconductors. PTFE is hydrophobic, requiring IPA prewetting when the filters are used in aqueous-based chemicals. Chemical filters are disposables, requiring the process equipment to be shutdown periodically to replace them. The time needed to IPA wet, water flush, chemical flush, and requalify the tool may be three hours; valuable time when wafers are not being processed. In addition, as the PTFE filters become tighter, there is more dewetting in outgassing chemicals containing hydrogen peroxide. This results in loss of flow in the systems and frequent changeout of filters. To improve the OEE of the process equipment, Millipore developed the QuickChange ? filter. The QuickChange process includes a modification to the PTFE membrane to make the surface less hydrophobic which eliminates dewetting in outgassing solutions. Flow and particle retention remain high in these outgassing baths even under severe conditions such as draining the housing during chemical change. Extractables, particle retention, and particle cleanliness of QuickChange filters are nearly identical to standard Millipore all-Teflon filters. Another convenience of QuickChange filters is that they are supplied prewet in a bag. The filters are ready to be installed into any aqueous-based process chemical. This paper will describe the attributes of the QuickChange filter products, present the results of extensive field testing, and quantify the potential improvement in Overall Equipment Efficiency.
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