IBM/Siemens tackle education of cycle time

01/01/1997

IBM/Siemens tackle reduction of cycle time

At the SEMI-sponsored Advanced Semiconductor Manufacturing Conference (ASMC), Cambridge, MA, Nov 12-14, Friedrich Boebel and O. Ruelle of the IBM-Siemens DRAM fab in Corbeil-Essones, France, examined cycle time reduction efforts at the facility. Among other findings, the pair noted that tool downtime was only the fourth largest detractor from cycle time in their study. The small number of tools for a given operation, and the need to dedicate tools to certain processes, were the leading detractors. The study found that cycle time increases sharply as the number of available tools for a given operation decreases. The authors noted that the drive toward high-throughput tools is "mostly cost-of-ownership driven," and does not take into account logistical problems caused by having only a handful of tools assigned to a process. They added that at the leading edge, engineers often solve process problems by dedicating a tool to an operation. "Especially in the litho area, this is a big problem," said the study, which suggested that engineers and equipment manufacturers should strive to reduce tool dedication to zero.