Patent ID: 8181596

Claim:
A cluster tool for processing a substrate, comprising: a first processing rack that comprises two or more vertically stacked substrate processing chambers, wherein the first processing rack has a first side and a second side; a second processing rack that comprises two or more vertically stacked substrate processing chambers, wherein the second processing rack has a first side and a second side; a first robot assembly positioned to access each of the two or more vertically stacked substrate processing chambers in the first processing rack from the first side; a second robot assembly positioned to access each of the two or more vertically stacked substrate processing chambers in the first processing rack from the second side and each of the two or more vertically stacked substrate processing chambers in the second processing rack from the first side; a third robot assembly positioned to access each of the two or more vertically stacked substrate processing chambers in the second processing rack from the second side; a cassette that is sized to retain two or more substrates; and a fourth robot assembly positioned to load a substrate in one of the processing chambers in the first processing rack, load a substrate in one of the processing chambers in the second processing rack, and load a substrate in the cassette.