JPS612322A - Heat-treating device - Google Patents

Abstract

PURPOSE:To prevent the inclusion of the outside air into a tube by a method wherein a gas stagnating part consisting of an annular recessed part is provided along the circumference of the aperture end of a processing tube, thereby enabling to stop the gas in the gas stopping part. CONSTITUTION:A cylindrical processing tube 11 is laterally provided in a furnace 12 having the heating means such as infrared rays and the like. The processing tube constitutes a small diameter part 14 and a large diameter part 15. A gas feeding tube 17 communicated to a reaction gas source 16 is connected to the small diameter part 14, and the necessary reaction gas can be introduced into the tube 11 by an interposed gas control part 18. On the other hand, the material to be processed can be taken in and out from the aperture 15, and the material 19 to be processed such as a semiconductor wafer and the like can be set at the required position in the tube 11 from the aperture 15. The tube aperture end 20 of the aperture part 15 is used as a gas stopping part by forming a square-ring shape recessed part 21 on the inner side, and a heating means 22 is provided around the aperture end 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heat treatment apparatus effective for manufacturing semiconductor devices, and particularly to a heat treatment apparatus having a process tube.

[Background technology]

2. Description of the Related Art Various heat treatment steps such as oxidation of semiconductor wafers and impurity diffusion are required in the manufacturing process of semiconductor devices, and various configurations of heat treatment apparatuses have been proposed accordingly. (Electronic materials November 1981 issue special issue J published by Kogyo Kenkyukai)
The heat treatment apparatus shown in FIG.
The tube 1 is configured to be able to heat the tube (mainly the middle portion) and to be able to introduce a reactive gas into the tube 1 from the narrow diameter portion 3 at its tip. In this case, the object to be heat-treated, such as a semiconductor wafer, is taken in and out of the tube from the large-diameter open end 4 of the tube 1, and during the heat treatment, the inside of the tube is isolated from the outside air by a cap 5 loosely fitted to the open end 4. You can do as you like.

However, in the heat treatment apparatus with this configuration, the gas inside the tube 1 heated by the furnace body 2 during heat treatment rises inside the tube along the tube wall as shown by arrow A, and rises along the tube wall as shown by arrow B. After flowing along the upper wall, the open end 4
A phenomenon occurs in which the liquid tends to leak out from the gap with the cap 5. When this phenomenon occurs, the temperature difference (T+>To
), a so-called entrainment phenomenon occurs in which outside air flows into the tube as shown by arrow C through the gap in the open end 4.

When such an entrainment phenomenon occurs, the temperature distribution inside the tube becomes uneven due to the intrusion of low-temperature outside air, inhibiting uniform heat treatment, and the inside of the tube is contaminated by dust contained in the outside air, or the surface of the semiconductor wafer is contaminated. Problems such as foreign matter adhesion and defects occur.

[Purpose of the invention]

The purpose of the present invention is to provide a heat treatment that prevents outside air from being drawn into the process tube, thereby making the temperature inside the tube uniform, and preventing contamination inside the tube and adhesion of foreign matter to the object to be processed. The goal is to provide equipment.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, a gas retention section consisting of an annular recess is provided at the periphery of the open end of the process tube, and the gas that is about to flow out from inside the tube is retained in this retention section, and this retained gas is used to prevent the gas from flowing into the tube. It is possible to prevent outside air from being drawn in, to make the temperature distribution inside the tube uniform, to prevent contamination inside the tube, and to prevent foreign matter from adhering to the object to be processed.

In addition, by attaching a heating means around the gas retention portion to make the temperature on the outside air side higher than the temperature at the tube opening end, the effect of preventing the outside air from being drawn in can be further improved.

〔Example〕

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, in which a furnace body 12 has a heating means 13 such as an RF coil or an infrared lamp.
A cylindrical process tube 11 is horizontally supported inside. The process tube 11 is made of quartz or the like, and has one end opened with a small diameter and the other end with the same diameter, forming a small diameter portion 14 and a large diameter opening (simply referred to as an opening) 15, respectively. .

A gas supply pipe 17 connected to a reactive gas source 16 is connected to the narrow diameter portion 14, and a required reactive gas can be introduced into the tube 11 by an interposed gas control unit 18. On the other hand, opening 1
5, the object to be processed can be taken in and out of the tube, and the object to be processed 19, such as a semiconductor wafer, mounted on a jig such as a boat can be set at a desired position in the tube 11 (approximately the middle position of the tube) through the opening 15. .

The tube opening end 20 of the opening 15 has its circumferential portion protruding in the outer radial direction, as shown in a partially enlarged view in FIG.
This is configured as a gas storage section. In this example, the gas retention portion 21 is formed integrally with the tube 11, but it may be formed separately and fixed together.

Further, a heating means 22 consisting of an annular heater is provided around the open end 20, and is configured to heat a portion of the open end 20 on the outside air side. Note that a cap 23 is loosely fitted to the open end 20.

According to the above configuration, while the inside of the tube 11 is heated by the furnace body 12, the reaction gas from the reaction gas source 16 is transferred to the narrow diameter portion 14.
By supplying into the tube 11 from
1 is set to a gas atmosphere condition of a required temperature. Then, by inserting the object 19 into the tube 11 from the open end 20 and capping it 23, the object is subjected to a predetermined heat treatment. At this time, the furnace body 1 inside the tube 11
The gas heated by step 2 rises along the upper wall of the tube as shown by arrow A, overflows the upper wall, and flows toward the opening 15 as shown by arrow B through the gap between the cap 23 and the opening end 20. leaked into the outside air. However, in this example, the open end 20
Since the gas retaining portion 21 is formed in the gas retaining portion 21, the gas that is about to flow out flows into the gas retaining portion 21 and is filled therein.

In other words, the entire circumference of the open end 20 is filled in the gas reservoir 21 . Therefore, the gap between the open end 20 and the cap 23 is filled with this retained gas, and it is possible to prevent the so-called entrainment in which outside air flows into the tube 11 through the gap, especially below the open end 20. can.

At this time, by simultaneously heating the outside air side of the open end 20 by the heating means 22, the temperature T on the outside of the open end 20 is
. can be made higher than the temperature T inside the cheap, which reverses the temperature relationship between the outside air and the internal gas from the conventional one, and in combination with the action of the gas retention section 21 described above, makes the entrainment of outside air even more effective. It can be prevented.

Therefore, since this device can effectively prevent the outside air from being drawn in, the temperature inside the tube 11 can be maintained uniformly, and the processing can be made more uniform. It is possible to effectively prevent the attachment of foreign matter to the workpiece 19 and the occurrence of defects due to this.

〔effect〕

(1) Since a gas retention section consisting of an annular recess is formed at the open end of the process cheep, gas that is about to flow out from inside the tube is temporarily retained in this gas retention section and fills the interior. This residual gas, especially at the bottom of the open end, prevents outside air from flowing into the cheep and prevents it from being engulfed, maintains a uniform temperature inside the tube, and prevents contamination inside the tube and adhesion of foreign matter to the object to be processed. can be prevented.

(2) Since a heating means is provided on the outside air side of the cheap opening end and the outside air side is set to a high temperature state, together with the action of the gas retention section, the entrainment of outside air can be more effectively prevented. I can do it.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor. For example, the cross-sectional shape of the recesses constituting the gas retention section can be of various shapes, such as a triangle or a solder shape, and if space is available, they may be arranged in two, three or more rows in parallel.

[Application field]

In the above explanation, the invention made by the present inventor is mainly applied to a heat treatment apparatus for manufacturing semiconductor devices, which is the background field of application, but it is not limited to this, and can be applied to various fields. It can be applied to heat treatment technology in

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of the device of the present invention, FIG. 2 is an enlarged view of the main parts, and FIG. 3 is a schematic configuration diagram of a conventional general device. 11... Process tube, 12... Furnace body, 14...
・Small diameter part, 15... Opening part, 16... Gas source, 19
...Object to be treated, 20...Open end, 21...Gas retention section, 22 Fig. 1 Fig. 2

Claims (1)

[Scope of Claims] 1. A heat treatment apparatus equipped with a cylindrical process tube into which a reaction gas can be introduced with an object to be treated set therein, and which can be heated to perform heat treatment. 1. A heat treatment apparatus, characterized in that a gas retention section consisting of an annular recess is formed at an open end. 2. The heat treatment according to claim 1, wherein the process tube is made of a cylindrical quartz tube, and the circumferential part along the open end of the process tube projects in the outer diameter direction, and the inner recessed part is configured as a gas retention part. Device. 3. The heat treatment apparatus according to claim 1 or 2, further comprising heating means for heating the outside air side of the open end at the outer peripheral position of the gas retention section.