| 摘要 |
PROBLEM TO BE SOLVED: To provide a vertical type heat treatment furnace which can prevent the damages of a wafer boat or a wafer from generating which is caused by the collision of the arm of a transfer robot against the wafer boat. SOLUTION: A peek window glass 66 is fitted in the rear door 14 of a loading-unloading chamber 11, and a sensor head 61 of an optical laser system displacement sensor 60 is fixed. One point of the side edge part of an upper end face plate 35 of a retaining bar 37 of a wafer boat is made to be a measurement point P. From a light projection part 62 of the head sensor 61, a laser light is irradiated almost vertically towards the measurement point P. Through the change in the amount of light in a light receiving part 63 which receives the reflected light from the point P, the inclination and the position shift of the wafer boat 31 which are caused by collision or the like of an arm 41 of a transfer robot 40 are detected in fine steps. Thereby the driving of the transfer robot 40 is stopped, before the wafer boat 31 is damaged. |
