A wafer-handling interface under processing ambient conditions for a single-wafer cluster tool

The pretreatment process used in semiconductor manufacturing can include over one-hundred processes, and about 90% of the wafer transfers are done between processors or process chambers that have different ambient conditions from each other; that is, between the atmosphere and a vacuum ambient or between a low and a high vacuum ambient. The throughput and yield from a semiconductor manufacturing line can be greatly improved by reducing the pumping and setting time of each process chamber ambient that is needed when transferring a wafer. We previously proposed a wafer-handling interface that operates under processing ambient conditions (the WHIPAC), with which the processing ambient conditions in the process chamber need not be changed for every wafer exchange and processing ambient fluctuations can be made smaller. We have developed a WHIPAC that allows the wafer in a process chamber under processing ambient conditions to be exchanged with a small mobile buffer chamber located in the transfer chamber at the center of a cluster tool used for single-wafer processing. This paper describes the principle of the WHIPAC for a single-wafer cluster tool and discusses the experimental results obtained from tests of a prototype system