Abstract: An apparatus for loading semiconductor wafers into a cantilever diffusion tube includes a cantilever paddle supporting a boatload of wafers. The paddle is moved into alignment with the open end of the cantilever diffusion tube. The open end portion of cantilever diffusion tube is moved to surround the paddle and boat load of wafers. The paddle is lowered slightly, causing the boat load of wafers to be supported on an inside surface of the cantilever diffusion tube and providing clearance around the paddle. The cantilever tube is withdrawn from the paddle, which then is withdrawn from the path of the cantilever diffusion tube. The cantilever tube and the boatload of wafers is moved into the hot zone of the furnace. After a heat treating operation, the cantilever diffusion tube is withdrawn from the furnace, and the reverse operation is performed to unload the boatload of wafers.

Abstract: A cantilever tube for carrying loaded wafer boats into a diffusion furnace and confining flow of gas through the wafers includes an elongated slot extending from an open end of the tube to a predetermined region in which the wafer boats are positioned, the wafer boats abutting each other and forming a sealing cover for the elongated slot. A narrow boat carrier supported on a carriage system extends through the elongated slot and carries a wafer boat loaded with wafers into the open end and to the predetermined region in the cantilever tube without allowing either the carrier, or the wafer boat, or the wafers to touch the cantilever tube. The carrier lowers the boat onto the bottom inner surface of the tube, causing the boat to cover a portion of the elongated slot. The procedure is repeated for subsequent wafer boats, each of which abuts the previous one, to effectively close and seal the elongated slot when all of the wafer boats are positioned inside the cantilever tube.