Abstract: A modular sorter is disclosed in which modular sections maybe easily added and removed to add and remove load port assemblies as required by a particular wafer fabrication run. In one embodiment, a modular sorter according to the present invention include a two-wide modular section defining a minienvironment for the sorter, a wafer handling robot a pair of aligners and a centralized controller. The modular section of this embodiment includes a pair of side-by-side load port assemblies for receiving a container or open cassette and presenting the cassette to the minienvironment of the sorter for processing of the wafers therein. The present invention further includes a removable end panel. When it is desired to add additional modular sections to the sorter, the end panel is removed and replaced by a connector frame. The connector frame allows additional modular sections, including either one load port assembly or two load port assemblies, to be attached to the original modular section.