Abstract: A substrate photolithography system includes a substrate handling robot which pivots about a fixed point and transfers substrates between photoresist coater, a developer, and a heating/cooling unit, all of which are clustered about the robot. The end effector of the robot is capable of both vertical and lateral movement so that individual modules of the heating/cooling unit may be stacked. An apparatus and a method for baking and cooling silicon substrates are disclosed. Both baking and cooling of silicon substrates are done in a single integrated thermal process module. Each thermal process module includes two hot plate assemblies, a cool plate assembly, two local linear transfer arms and a micro-processor based module controller. Both transfer arms are capable of transferring substrates among the cool and hot plate assemblies. A cassette input/output unit handles cassettes which contain semiconductor wafers or other substrates that are to be delivered to or withdrawn from a semiconductor processing system.

Abstract: A cassette input/output unit handles cassettes which contain semiconductor wafers or other substrates that are to be delivered to or withdrawn from a semiconductor processing system. The input/output unit includes a drawer front which rotates 90.degree. about a horizontal axis as it is opened. Thus a cassette containing wafers can easily be placed on the drawer front with the wafers oriented vertically, as they are normally carried, and the cassette will be rotated 90.degree. as the drawer is closed, thereby orienting the wafers horizontally for access by a robot inside the photolithography system. The cassette may also be rotated about a vertical axis within the unit, so that several input/output units may be used with a robot which rotates about a fixed axis. A clamping mechanism grips the cassette firmly when it is placed in the unit.