Patent ID: 7547209

Claim:
A vertical heat treatment system comprising: a heat treatment furnace; a holder that is loaded and unloaded into and from the heat treatment furnace while the holder holds a plurality of process objects which are arranged at multiple level and spaced at vertical intervals; a transfer mechanism that transfers process objects between the holder and a container adapted to hold a plurality of process objects at predetermined intervals, the transfer mechanism including a base adapted for vertical movement and turning movement, and a plurality of substrate holding devices, each adapted to support a process object, mounted to the base so as to be movable anteroposteriorly, wherein one of the plurality of substrate support devices is configured to move anteroposteriorly and independently from the other substrate support devices; a first sensor, attached to the base, that emits a light beam directed toward a direction in which the substrate support device moves, and detects a target member upon receipt of a reflected light of the light beam; a second sensor, attached to two tip end portions of said one of the substrate support devices, that detects the target member upon interruption of a light beam traveling between the tip end portions by the target member; and a control unit that deduces the target position based on detection signals of the first and second sensors and encoder values of drive systems of the transfer mechanism associated with the detection signals, and recognizes the target position thus deduced.