A vertical batch furnace assembly for processing wafers comprising:
- a cassette handling space provided with a cassette storage configured to store a plurality of wafer cassettes provided with a plurality of wafers and a cassette handler configured to transfer wafer cassettes between the cassette storage and a wafer transfer position;
- a wafer handling space comprising a substantially rectangular shape and provided with a wafer handler configured to transfer wafers between a wafer cassette in the wafer transfer position and a wafer boat in a wafer boat transfer position;
- and
- an internal wall separating the cassette handling space and the wafer handling space and provided with a wafer transfer opening adjacent the wafer transfer position for a wafer cassette from or to which wafers are to be transferred, wherein the cassette storage comprises a cassette storage carousel with a diameter between 1.1 and 1.6 meter;
- a first process chamber for processing wafers accommodated in a wafer boat;
- a second process chamber for processing wafers accommodated in a wafer boat;
- and
- a single wafer boat handling device comprising one rotatable table having a plurality of wafer boat support surfaces each configured for supporting a wafer boat, wherein the rotatable table is rotatable by an actuator around a central substantially vertical axis to transfer each wafer boat support surface to:
- a first wafer boat load/receive position in which the wafer boat handling device is configured to load a wafer boat vertically from the rotatable table into the first process chamber and to receive the wafer boat from the first process chamber onto the rotatable table;
- and
- a second wafer boat load/receive position in which the wafer boat handling device is configured to load the wafer boat vertically from the rotatable table into the second process chamber and to receive the wafer boat from the second process chamber onto the rotatable table,
- wherein the cassette storage carousel comprises a platform stage configured to accommodate 5 or more wafer cassettes,
- wherein the vertical batch furnace assembly is provided with a substantially rectangular footprint having two opposite short sides defining a width of the vertical batch furnace assembly and having two opposite long sides defining a length of the vertical batch furnace assembly, wherein the width of the vertical batch furnace assembly is 1.65 meter or less, and
- wherein the cassette handler is provided with a pivotable cassette handler arm and an elevator mechanism, the pivotable arm configured to reach wafer cassettes at different vertical heights within the cassette storage, and
- wherein the cassette storage carousel is disposed between the elevator mechanism and the internal wall and there is no overlap of the elevator mechanism and the cassette storage carousel in a direction spanning between the two opposite short sides.