PCT No. PCT / JP97 / 00526 Sec. 371 Date Aug. 31, 1998 Sec. 102(e) Date Aug. 31, 1998 PCT Filed Feb. 25, 1997 PCT Pub. No. WO97 / 32339 PCT Pub. Date Sep. 4, 1997An heat-treating ring boat (20) for
semiconductor wafers (W) has a top plate (21), a bottom plate (22), six columns (23-28), and 63 ring trays (31). The trays (31) are mounted in grooves (20a) of the columns (23-28). To fix the trays (31), a fixing rod (33) is detachably mounted between the top plate (21) and bottom plate (22). A through hole (21a) and a recessed portion (22a) to
mount the fixing rod (33) therein are formed in the top plate (21) and bottom plate (22). Notches (34) to engage with the fixing rod (33) are formed in the trays (31). A notch (32) to engage with the fixing rod (33) is formed in the column (23). A projection (41) is formed on each tray (31) to abut against the side surface of the column (24).