Vertical heat treatment apparatus having wafer transfer mechanism and method for transferring wafers

Claim 1

A wafer transfer apparatus for transferring a semiconductor wafer between a boat and a cassette for loading wafers, said boat having a plurality of wafers horizontally loaded therein and having at least two support rings each having an opening smaller in diameter than the wafer, comprising: a station having a cassette mounted thereon; convey means provided with a plate-like arm for taking out and transferring the wafer from the cassette mounted on said station, and horizontally moving said arm to a region above the opening of the support ring; receiving means provided with a receiver for receiving the wafer from the arm and horizontally moving said receiver to a region below the opening of the support ring; means for vertically moving the receiver; a projecting member mounted on the receiver for supporting the wafer; and a common assembly frame having both the receiver and the arm mounted thereon movably in the same direction.

Claim 3

A method of transferring a semiconductor wafer between a cassette and a boat including at least two support rings coaxially arranged with a predetermined pitch between each of the support rings and each provided with an opening having a diameter smaller than that of the wafer, comprising the steps of: picking up the wafer from the cassette on a station by an arm in a substantially horizontal state; inserting the arm into the boat for positioning the wafer supported by said arm above an opening of the support ring; allowing a receiver and said arm to approach the boat in the same direction for positioning the receiver below said opening of the support ring; moving said receiver upward to a position where a projecting member mounted on said receiver reaches said arm through the opening of the support ring; lifting the wafer from said arm by said projecting member; moving said arm to retreat from said boat; moving said receiver downward to a position where the wafer is transferred from said receiver to said support ring; and loading the wafer on the support ring such that a distance between a top face of a first wafer and a bottom face of a second wafer is larger than a distance between a top face of a first support ring and a bottom face of a second support ring.

Claim 4

A method of transferring a semiconductor wafer between a cassette and a boat including at least two support rings coaxially arranged with a predetermined pitch between each of the support rings and each provided with an opening having a diameter smaller than that of the wafer, comprising the steps of: picking up the wafer from the cassette on a station by an arm in a substantially horizontal state; inserting the arm into the boat for positioning the wafer supported by said arm above an opening of the support ring; allowing a receiver and said arm to approach the boat in the same direction for positioning the receiver below said opening of the support ring; moving said receiver upward to a position where a projecting member mounted on said receiver reaches said arm through the opening of the support ring; lifting the wafer from said arm by said projecting member; moving said arm to retreat from said boat; moving said receiver downward to a position where the wafer is transferred from said receiver to said support ring; and loading the wafer on the support ring such that a distance between a top face of a first wafer and a bottom face of a second wafer is larger than a distance between a top face of a first support ring and a bottom face of a second support ring.