CAGE-SHAPED BOAT

PURPOSE:To make the thickness of a film uniform even when used for LTO by restricting the flow of process gas to an element to be treated, to cope with the automation of transferring the element, and to be adapted for use in a vertical furnace by disposing a plurality of substantially circular partition members at each predetermined patch. CONSTITUTION:A boat 10 having a plurality of substantially disclike elements 18 disposed to be supported is supported by disposing a plurality of substantially circular partition members 20 formed along approximately whole periphery of the elements 18 at each predetermined pitch, and inserting the elements 18 between the members 20 to support them, and process gas is introduced on the elements 18 from slits 25 between the members 20. For example, the cage-shaped board 10 has partition members 20, side plates 12, 14, four supporting plates 16, and the like. The member 20 has a circular gas restricting ring 22 formed along approximately whole periphery of a wafer 18 and an inner ring 23 abutted against approx. 180 deg. of the outer edge of the wafer 18 for forming a step for supporting the wafer 18.