JPH01302816A - Vertical type heat treatment device - Google Patents

Abstract

PURPOSE:To prevent a substance within gas discharged from a reaction pipe to be adhered to a discharge path and to improve productivity as compared with the conventional method by providing means for heating the discharge path for performing discharge from the reaction pipe. CONSTITUTION:In a vertical type heat treatment device for performing heating by circulating a specified gas within a cylindrical reaction pipe which is placed nearly vertically, a means 7 for heating is provided at a discharge path 4 for performing discharge from the reaction pipe 1. For example, the reaction pipe 1 constituted cylindrically from a quartz, etc., is placed nearly vertically and a cylindrical heater 2 and a uniform heat pipe, heat insulating material, etc., are placed surrounding the reaction pipe 1. Also, a reaction gas guiding pipe 3 and a discharge pipe 4 are connected to the upper and lower parts of the reaction pipe 1 for guiding and discharging a specified reaction gas and a cooling trap 5 and a discharge device 6 are inserted into the discharge pipe 4. Then, a heating mechanism 7 for heating the inside of the discharge pipe 4 consisting of a tape heater, etc., is provided within the discharge pipe 4 among between the connection of the reaction pipe 1 of the discharge pipe 4 and a cooling trap 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a vertical heat treatment apparatus for heating and processing a substrate to be processed, such as a semiconductor wafer.

(Prior art) Conventionally, as a heat treatment apparatus for heating a substrate to be processed such as a semiconductor wafer to perform processes such as thin film formation and thermal diffusion, horizontal heat treatment apparatuses in which reaction tubes are arranged almost horizontally have been mainly used. However, in recent years, vertical heat treatment apparatuses in which reaction tubes are arranged almost vertically have come into widespread use in view of the ease of loading and unloading wafers.

In other words, in such a vertical heat treatment apparatus, a cylindrical reaction tube made of quartz or the like is arranged almost vertically, and a large number of semiconductor wafers are stacked at intervals on a wafer boat made of quartz or the like. The semiconductor wafer is loaded and unloaded from below into the reaction tube by a transport mechanism that is arranged so as to be able to move up and down, for example. Such a vertical heat treatment apparatus has the advantages of being able to easily load and unload the reaction tube inner wall and the wafer boat without contact, occupying a small area, and increasing the diameter of semiconductor wafers to be processed. It has the following advantages.

(Problems to be Solved by the Invention) When forming a film using the vertical heat treatment apparatus described above, various reaction gases are passed through the reaction tube depending on the type of film. Substances in the gas may adhere to the exhaust path as the temperature decreases.

For example, when depositing a film containing phosphorus, phosphine (
A gas such as PH3) is passed through the reaction tube, but at this time, phosphorus pentoxide (P2O3) and the like adhere to the exhaust path. Therefore, maintenance is required to remove such deposits, resulting in a problem of deterioration of productivity.

The present invention has been made in response to such conventional circumstances, and can prevent substances in the gas exhausted from the reaction tube from adhering to the exhaust route, resulting in improved productivity compared to the prior art. The purpose of this invention is to provide a vertical heat treatment apparatus that can achieve the desired results.

[Structure of the Invention] (Means for Solving the Problems) That is, the present invention provides a vertical heat treatment apparatus that performs heating by circulating a predetermined gas in a cylindrical reaction tube disposed approximately vertically. The present invention is characterized in that heating means is provided in the exhaust path through which exhaust air is discharged from the air.

(Function) In the vertical heat treatment apparatus of the present invention having the above configuration, by heating the exhaust route to a temperature higher than the melting point of deposits by means of heating the exhaust route, the exhaust route is heated from the reaction tube to the exhaust route. This prevents substances in the gas from adhering to the surface.

The substances in this gas are then captured, for example, by a cold trap.

Therefore, maintenance for removing deposits that have adhered to the inside of the exhaust pipe is unnecessary, and productivity can be improved compared to the conventional method.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

For example, a cylindrical reaction tube (process tube) 1 made of quartz or the like is arranged almost vertically, and surrounding the reaction tube 1 are a cylindrical heater 2, a heat equalizing tube (not shown), a heat insulating material, etc. is provided. In addition, this reaction tube 1
A reaction gas introduction pipe 3 and an exhaust pipe 4 for introducing and exhausting a predetermined reaction gas are connected to the upper and lower parts of the reactor, respectively, and a cooling trap 5 and an exhaust device 6 are inserted into the exhaust pipe 4. has been done. A heating mechanism 7 consisting of a means for heating the inside of the exhaust pipe 4, such as a tape heater, is disposed between the connection part of the exhaust pipe 4 with the reaction tube 1 and the cooling trap 5.

Further, the cooling trap 5 is constructed as shown in FIGS. 2 and 3. That is, a trap container 20 formed of, for example, quartz or the like into a substantially cylindrical shape has a four part 21 formed at the center of the bottom, an inlet pipe 22 along the tangential direction at the upper peripheral edge, and an inlet pipe 22 at the upper center part. is connected to the outlet pipe 23. Further, inside the trap container 20, a cylindrical partition plate 24 is provided from above with a space between it and the bottom surface, and the artificial pipe 22
The structure is such that the gas flowing in from the pipe descends while rotating spirally as shown by the arrow in the figure, and then rises and is led out from the outlet pipe 23. This trap container 20 is fitted into a water cooling jacket 25 and is configured to be able to be cooled with high efficiency from the outside and inside (four parts 21).

Further, a boat elevator 8 is provided below the reaction tube 1 and is capable of moving up and down together with the transport mechanism. A heat insulating cylinder 9 is provided on the boat elevator 8, and the heat insulating cylinder 9 is configured to be able to support a wafer boat 11 on which a large number of semiconductor wafers 10 are stacked at intervals. ing. The boat elevator 8 is configured to load and unload the semiconductor wafers 10 placed on the wafer boat 11 into the reaction tube 1 from the lower opening of the reaction tube 1 .

In the vertical heat treatment apparatus of this embodiment having the above configuration, the heater 2
The inside of the reaction tube 1 is heated in advance to a predetermined temperature, for example, about several hundred degrees, and the boat elevator 8 is raised to raise the semiconductor wafer 10 placed on the wafer boat 11 into the reaction tube 1 without contacting the inner wall of the reaction tube 1. Load into. Then, a predetermined reaction gas, for example, S
'iH4,02, B2 H6, PH3, etc. are introduced, and after the semiconductor wafer 10 is heated, it is evacuated from the exhaust pipe 4 by the exhaust device 6 to form a film.

At this time, when forming a film containing phosphorus using, for example, PH3 as a reaction gas, the heating mechanism 7 heats the inside of the exhaust pipe 4 to, for example, about 150°C, and the water cooling jacket 25 of the cooling trap 5 The trap container 20 is cooled by circulating cooling water. Therefore, for example, the generated phosphorus pentoxide does not adhere to the inside of the exhaust pipe 4.
When it flows into the trap container 20 of the cooling trap 5 and descends and rises while rotating spirally, it is captured in the trap container 20 due to centrifugal force and cooling effects. That is, by setting the temperature of the exhaust pipe 4 in advance according to the type of gas to be handled, it is possible to automatically set the temperature to the optimum temperature.

After performing open film formation at a predetermined time, the flow of the reaction gas is stopped, and the boat elevator 8 is lowered to unload the semiconductor wafers 10 placed on the wafer boat 11 from the reaction tube 1. A film of a predetermined thickness is formed on 10.

That is, in the vertical heat treatment apparatus of this embodiment, the exhaust pipe 4
A heating mechanism 7 consisting of, for example, a tape heater is disposed between the connection part with the reaction tube 1 and the cooling trap 5. By heating the inside of the exhaust pipe 4 with this heating mechanism 7, the phosphorus is removed. It is possible to prevent phosphorus pentoxide generated when forming a film containing phosphorus from adhering to the inside of the exhaust pipe 4.

Further, since this phosphorus pentoxide is captured by the cooling trap 5, it is not discharged to the outside, and the captured phosphorus pentoxide can be easily removed by removing the trap container 20 from the water cooling jacket 25 and cleaning it. I can do it. Therefore, there is no need to perform maintenance to remove deposits that have adhered to the inside of the exhaust pipe 4, as in the conventional case.
Productivity can be improved compared to the conventional method.

In the above embodiment, a case was explained in which a film containing phosphorus was formed. However, in the case where other substances adhere to the inside of the exhaust pipe 4, for example, the inside of the exhaust pipe 4 may be heated to a temperature higher than the melting point of the substance. Of course, it is possible to prevent this from sticking by heating it to Further, although an example has been described in which a tape heater is used as a heating means for the exhaust system, any heating means may be used, such as lamp heating or heater heating.

[Effects of the Invention] As described above, in the vertical heat treatment apparatus of the present invention, it is possible to prevent substances in the gas exhausted from the reaction tube from adhering to the exhaust path, resulting in improved productivity compared to the conventional method. You can improve your performance.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a vertical heat treatment apparatus according to an embodiment of the present invention, FIG. 2 is a top view of the cooling trap shown in FIG. 1, and FIG. 3 is a longitudinal sectional view of the cooling trap shown in FIG. 2. . 1...Reaction tube, 2...Heater, 3...
... Reaction gas introduction pipe, 4 ... Exhaust pipe, 5.
...Cooling trap, 6...Exhaust device, 7
... Heating mechanism, 8 ... Boat elevator, 9 ... Heat insulation cylinder, 10 ... Semiconductor wafer 1.11 ... Wafer bow 1° Applicant Chill Sumo Co., Ltd. Agent Patent Attorney Sasa Suyama - Figure 1

Claims (1)

[Claims] (1) A vertical heat treatment apparatus that heats a predetermined gas by flowing it through a cylindrical reaction tube arranged almost vertically, characterized in that a means for heating is provided in an exhaust path that exhausts air from the inside of the reaction tube. Vertical heat treatment equipment.