| 摘要 |
PROBLEM TO BE SOLVED: To enable the accurate carry-in and carry-out of a wafer into or out of a diffusion furnace. SOLUTION: The diffusion furnace 10 is provided with a carry-in/carry-out controller 12. A controller 14 included in the carry-in/carry-out controller 12 controls the vertical movement of a boat elevator 34, according to the instruction of the operator. While the boat elevator is moving up, the number of pulses from an encoder 22a is counted by a counter 14a. When the counted value is consistent with a counted value P stored in a register 14b, the controller 14 stops the movement of the boat elevator 34. Here, when an upper limit sensor 24 is at on-state, the controller 14 proceeds to a diffusion process. In contrast, when the upper limit sensor 24 is at off-state, the controller 14 forcibly moves the boat elevator 34 to an upper limit position B and then proceeds to a diffusion process. When the diffusion process is finished, the boat elevator 34 is moved down, based on the counted value of pluses as in the upward movement, to be forcibly moved downward to a lower limit position A, based on the output from a lower limit sensor 26. |
