The development of batch type low pressure spin dryer for water mark-less wafers

We developed a novel spin dryer, which is equipped with high speed rotation capability and a low pressure N/sub 2/ purging system, to realize a water mark free surface. Water marks which remained on the Si wafer surface were made by chemical reaction of Si, O/sub 2/, and H/sub 2/O during spin drying. In this paper, two experimental approaches: (1) to remove O/sub 2/ from the reaction elements; and (2) to minimize reaction time, were demonstrated. The low pressure, high speed spin dryer with shower rinsing suppressed water marks significantly, i.e. only 500 ppm, compared with that of a conventional one.