HEAT TREATMENT FURNACE

摘要

PROBLEM TO BE SOLVED: To provide a heat treatment furnace by which reduction of impurity contamination on a semiconductor wafer for heat treatment and influence on the surface quality are reduced by reducing particles in the heat treatment process of the semiconductor wafer. SOLUTION: In the heat treatment furnace having a process tube at least from a furnace port through which a semiconductor wafers are inserted and to a furnace tailing port to which a gas supply tube is connected, a liner pipe into which the process tube is inserted and a heater arranged at the perimeter of the liner pipe, the inner diameter of the process tube has a smaller diameter portion than that of the soaking region at a heating region apart from a soaking region of the process tube at the tailing port.