Semiconductor wafers within a supporting vertical wafer tower are positioned within a vertical process chamber through a lower gate valve fixed to a supporting framework. The gate valve is sealed to a similar gate valve at the upper end of a movable load lock on the framework, within which the wafers...http://www.google.de/patents/US5000682?utm_source=gb-gplus-sharePatent US5000682 - Vertical thermal processor for semiconductor wafers
