JPS63137420A - Heating furnace - Google Patents

Abstract

PURPOSE:To make the heat capacity of the main body of a heating furnace small and to improve the increasing and decreasing characteristics of temperature, by arranging an inner tube made of SiC, which has a specified interval with an outer tube, in the outer tube in a suspended state in a space, and providing a heater with an insulator in the inner tube. CONSTITUTION:An inner tube 5 comprising SiC is arranged approximately coaxially with an outer tube 1. A mullite tube 6 is provided between the outer tube 1 and the inner tube 5. An insulating material 2 is provided between the mullite tube 6 and the outer tube 1. Thus heat retaining property in a heating furnace can be improved. The outer tube 1, the mullite tube 6 and the inner tube 5 are kept in the suspended state in a space with heat insulating rods 7. A heater 3 is fixed to the inner tube 5 with an insulator. In this way, the heat capacity of the main body of the heating furnace is made small, the increasing and decreasing characteristics of temperature can be improved and the uniform region of the temperature distribution in the heating furnace can be expanded by the heat conductivity of the SiC inner tube.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvement of a heating furnace in semiconductor manufacturing equipment.

[Prior art] Thermal oxidation, thermal acid expansion, and CVD are used in the manufacturing process of semiconductor devices.
(Chemical Vapor Deposition), annealing, and other applications of heating furnaces are wide-ranging, and heating furnaces are becoming an increasingly important element in semiconductor manufacturing processes. The characteristics required for this heating furnace include uniform temperature distribution within the heating furnace, excellent heat retention, high temperature resistance, rapid temperature rise and fall characteristics, and dust generation prevention. It is convenient to use, and it is convenient to use.

In conventional heating furnaces, refractory bricks and asbestos have been used as insulation materials to maintain heat retention inside the heating furnace, but the heat capacity of the heating furnace itself is large, making it difficult to rapidly raise and lower the temperature. Dust generation from the insulation material was a problem. Regarding the uniformity of temperature distribution in the heating furnace, the heating element was placed on the heat insulating material, and the soaking range (heat soaking length) remained around 1/2 of the furnace length.

[Problems to be Solved by the Invention] The present invention eliminates the above-mentioned conventional drawbacks, reduces the heat capacity of the heating furnace main body, improves rapid temperature rise and fall in the heating furnace, and achieves uniform temperature distribution. The purpose of the present invention is to provide a heating furnace that has an expanded area and eliminates the problem of dust generation from the heating furnace itself.

[Means for Solving the Problems] In order to achieve the above object, the heating furnace of the present invention has a heating furnace made of SiC that is substantially coaxial with the tubular outer tube and has a certain distance from the outer tube. The inner pipe of is suspended in the outer pipe,
A heating element is disposed in the inner tube using an insulator, and one or more mullite tubes are provided between the outer tube and the inner tube, and a heat insulating effect is maintained by the air layer between the outer tube and the mullite tube. It is also possible to further improve the insulation effect by inserting a heat insulating material between the outer tube and the mullite tube.

This makes it possible to reduce the heat capacity of the heating furnace body, improve the temperature rise and fall characteristics, and further improve the temperature fall characteristics by sending air between the outer tube and the inner tube. This can be prevented by using an inner tube and a mullite tube. Regarding the uniformity of temperature inside the heating furnace, the heating element is placed in an inner tube made of SiC, which has good thermal conductivity, so the heat conduction effect of the inner tube maintains uniformity of temperature distribution inside the heating furnace. Can be expanded.

[Example] Fig. 1 shows a conventional heating furnace, and Fig. 2 shows an embodiment of the heating furnace according to the present invention. In FIG. 2, an inner tube (SiC) 5 is disposed substantially coaxially with the outer tube 1.

By disposing the mullite tube 6 between the outer tube 1 and the inner tube 5 and inserting the heat insulating material 2 between the mullite tube 6 and the outer tube 1, the heat retention inside the heating furnace can be further improved.

The outer tube 1, the mullite tube 6, and the inner tube 5 are each maintained in a suspended state by a heat-insulating support rod 7.

A heating element 3 is fixed to the inner tube 5 via an insulator 8.

Details of the fixing method are shown in FIGS. 3 and 4.

FIG. 3 shows an example in which the heating element 3 is fixed to the outside of the inner tube 5,
FIG. 4 shows an example in which the heating element 3 is fixed inside the inner tube 5.

In FIG. 3, a plurality of circumferential grooves II are provided in the inner tube 5, a plurality of fixing plates lO are provided on the outside of the inner tube 5 using the grooves II as a guide, and the heating element 3 is fixed with screws through an insulator 8. 9 to fix it to the inner tube 5.

In FIG. 4, when the heating element 3 is arranged inside the inner tube 5,
The inner tube 5 is cut in half, and the heating element 3 is disposed inside the inner tube 5 with a fixing screw 9 via an insulator 8.

In addition, the outer tube 1 is plated with gold on the inside to increase thermal efficiency in the heating furnace and improve heat uniformity.
A water cooling pipe 4 is provided for protection.

As shown above, by reducing the heat capacity of the heating furnace body,
The object of the present invention is to provide a heating furnace that is characterized by improved temperature rise and fall characteristics and by expanding the uniform temperature distribution region of the heating furnace due to the thermal conductivity of the SiC inner tube.

[Brief explanation of the drawing]

FIG. 1 shows a conventional heating furnace, and FIG. 2 shows an embodiment of the heating furnace according to the present invention. FIG. 3 shows an example in which the heating element is fixed to the outside of the inner tube, and FIG. 4 shows an example in which the heating element is fixed to the inside of the inner tube. 1-111 Outer tube 6-- Mullite tube 2-- Insulation material 7-- Support rod 3--m-Heating element 8-1 Insulator 4--M-Cooling pipe 9--M-Fixing screw 5
---1 Inner pipe 10--1 Fixing plate 11
--- Fixed guide drawing γρ paper 111 Director General of the Patent Office Kunio Ogawa 1. Indication of the case 3, Relationship with the case of the person making the amendment Patent question address Postal code 214 6-20-3-5 Nagao, Tama-ku, Kawasaki City, Kanagawa Prefecture Drawing 6 to be amended, Contents of the amendment as per attached sheet

Claims (1)

[Scope of Claims] 1) A tubular outer tube and an inner tube that is substantially concentric with the outer tube and spaced from the outer tube by a certain distance are suspended from the outer tube; 1. A heating furnace characterized in that an inner tube is made of SiC in a heating furnace in which a heating element is disposed with an insulator. 2) When the heating element is disposed outside the inner tube, a plurality of grooves are provided in the circumferential direction on the outside of the inner tube, and a plurality of heat-resistant band-shaped fixing plates are fitted into the circumferential grooves. A method of fixing the heating element to the fixing plate using an insulator. 3) When disposing a heating element inside the inner tube, the inner tube is divided in half, and a plurality of through holes are provided in the inner tube, and an insulator attached to the through holes is provided inside the inner tube. A method of fixing a heating element using an insulator. 4) A heating furnace characterized in that a single mullite tube or a plurality of mullite tubes are arranged between an outer tube and an inner tube made of SiC at a predetermined interval on a substantially concentric axis with the outer tube and the inner tube. 5) A heating furnace comprising a plurality of mullite tubes according to claim 4 above, in which a heat insulating material is inserted between the mullite tubes.