JPS6449220A - Heat treatment furnace - Google Patents

Abstract

PURPOSE:To detect the temperature inside a reaction tube and the temperature outside the reaction tube simultaneously and control the temperature inside the reaction tube at a required temperature in a short time by providing a 1st temperature sensor protected by a protective tube inside the reaction tube and 2nd temperature sensors outside the reaction tube. CONSTITUTION:A first thermocouple 27 protected by a protective tube 28 is provided inside a reaction tube 20. Second thermocouples 34 are provided outside the reaction tube 20. The thermocouples 27 and 34 are respectively connected to a controller. With this constitution, when a boat on which wafers are placed is provided in the reaction tube 20 for a heat treatment, both the temperature inside the reaction tube 20 and the temperature outside the reaction tube 20 can be detected simultaneously and both the temperature data can be compared with each other regardless to that the temperatures are detected before, at the time of or after the heat treatment. Therefore, the temperature inside the reaction tube 20 can be predetermined at a required temperature with a high accuracy and in a short time without a delay time accompanying taking the wafers into and out of the reaction tube like a conventional constitution.