A semiconductor processing system which includes: a first semiconductor wafer cassette for housing semiconductor wafers; a first transfer pod for enclosing the first cassette airtightly, the first pod having a box-like pod body with an open bottom and a bottom plate detachably attached to the pod body for closing the bottom of the pod body; a wafer processing equipment having a first port for loading the cassette and a canopy covering the first port, the processing equipment processing the wafer in the first cassette when the cassette is loaded in the first port; and a first mechanism for transferring the first cassette between the first port of the processing equipment and the first pod without exposing the cassette and the wafers therein to outside contamination. The first transferring mechanism includes: a second port, provided on the canopy of the processing equipment at the position directly above the first port, for placing the first pod on the second port, the second port including a port assembly for attaching and detaching the bottom plate of the first pod to and from the pod body when the first pod is placed on the second port; and a first lift mechanism, arranged mainly between the first and second ports, for conveying the bottom plate of the first pod between the first and second ports when the bottom plate of the pod is detached from the pod body.