A substrate processing apparatus comprises a substrate transfer section, a
plurality of modules and a first substrate transfer robot provided in the
substrate transfer section and capable of transferring substrates to the
plurality of modules. The plurality of modules are piled up, separately
from one another, in a vertical direction. Each of the plurality of
modules are detachably mounted to the substrate transfer section and
includes a substrate processing chamber, an intermediate chamber, a first
gate valve disposed between the substrate processing chamber and the
intermediate chamber, a second gate valve disposed between the
intermediate chamber and the substrate transfer section, and a second
substrate transfer robot disposed in the intermediate chamber.
Preferably, the substrate processing chamber further comprises a second
intermediate chamber having a substrate holder therein and disposed
between the intermediate chamber and the substrate transfer section, and
a third gate valve disposed between the second intermediate chamber and
the substrate transfer section.