Aspects of the invention include methods and apparatus for processing a batch of substrates. In one embodiment, a compressed substrate boat is configured to reduce pumping volume in a batch processing chamber. The compressed substrate boat comprises a stationary substrate boat and a movable substrate boat, each may be loaded/unloaded independently. The movable substrate boat and the stationary substrate boat may be interleaving with one another such that the distance between the substrates is reduced. In another embodiment, a substrate boat having removable substrate holder is configured to provide susceptors without dramatically increasing pumping volume. The removable substrate holder may be loaded/unloaded away from the substrate boat with susceptors. The removable substrate holder is engaged with the substrate boat such that substrates thereon are interleaving with the susceptors. Embodiments of the present invention reduces pumping volume and increases throughput, hence reduces cost of ownership during batch processing.