SEMATECH develops next generation handling system

JULY 22–AUSTIN, Texas–International Sematech, a research and development consortium, has validated a fourth-generation automated material handling system (AMHS) that combines independently made overheard transport (OHT) and conveyor systems within a 300 mm fab.

That qualification at Sematech’s Advanced Technology Development Facility (ATDF) involved integrating an SK Daifuku Cleanway CLW-07 OHT monorail system with a Clean Drive conveyor transport system made by Middlesex General Industries.

It was the first time that such a combination has successfully occurred in a 300 mm manufacturing environment, according to Sematech design engineers.

“This fourth-generation system provides several advantages over the conventional types of transport systems currently in use in the industry,” Marlin Shopbell, AMHS project manager for Sematech, said in a statement. “It provides better throughput, more flexibility, and greater tool utilization.”
The Sematech fourth-generation system enhances the unified system with a capacity to bypass the stocker by placing a FOUP in a buffer directly in front of the tool if the tool load ports are occupied. “The FOUP stays close to where it’s needed, instead of in a stocker that might be 30 to 40 meters away,” Shopbell said.

The Sematech system was installed in a 2800-square-foot section of the ATDF’s automated copper line, using a 270-foot-long Middlesex conveyor system with bidirectional capabilities, and equipped with stocker and tool buffer zones, Sematech said. It was combined with an 80-foot-long Daifuku OHT providing direct delivery to load ports using bidirectional vehicles and custom transfer points to and from the conveyor.

The unified system processed wafers through seven tools, including two furnaces, planarizer, wafer sorter, plating tool, and two deposition tools. It also demonstrated FOUP and load port interoperability by employing FOUPs from three suppliers on five different types of tool load ports within the same cell, according to the consortium.

“The marriage of cleanroom conveyor technology with existing OHT technology will help the industry move toward fully automated, direct tool-to-tool wafer delivery,” Shopbell said. “This system could be ready for industry use within two years, and becoming common perhaps by 2007.”

First-generation systems use overhead, non-hoist vehicles to move front opening unified pods (FOUPs) — from stocker to stocker between tool bays, and carts or person-guided vehicles for transportation within a bay.

Second-generation systems incorporate OHT equipment to move lots from stockers to tools within bay.

Third-generation systems offer unified interbay and intrabay transport, utilizing OHT technology to bypass stockers and deliver lots directly from tool to tool. If tool load ports are in use, however, the FOUP waits in a stocker.


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