JPH04135601A - Method for cleaning trap - Google Patents

Abstract

PURPOSE:To prevent the scattering of a trapped material, to improve safety and to obviate the generation of dust by injecting an org. caking agent into the trap to cake the trapped material, then demounting the trap from an evacuating line and treating the trapped material together with the caking agent. CONSTITUTION:A trap 1 inserted in an evacuating line 30 and used for trapping the harmful matter in a gas circulating through the line 30 is cleaned. In this case, an org. caking agent 43 (e.g. urethane foam) is injected into the trap 1 from a caking agent feeder 42 to cake the trapped material 41, then the trap 1 is demounted from the line 30, and the trapped material 41 is treated along with the caking agent 43. Namely, the trapped material is not scattered when the trap is demounted from the line 30, hence safety is improved, and the dust, etc., decreasing the yield of the product are not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for cleaning a trap device installed in an exhaust system.

(Prior Art) Conventionally, a heat treatment apparatus has been used in a film forming process, a thermal diffusion process, etc. in the manufacturing process of semiconductor devices.

In such heat treatment equipment, multiple semiconductor wafers are housed in a reaction vessel made of quartz or the like that can maintain a vacuum, and after the inside of the reaction vessel is evacuated to a predetermined reduced pressure state using a vacuum pump, etc., reactive gases and oxidation gases are removed. Along with introducing sexual gas etc.
By raising the temperature to a predetermined reaction temperature, a Si epitaxial growth film, an oxide film, etc. are formed. As the reactive gas, for example, 5iTo 012-IC+
82 and the like are used, as well as compounds to which compounds that are raw materials for arsenic and phosphorus are added.

By the way, the exhaust gas from the heat treatment equipment mentioned above contains harmful substances such as unreacted film-forming gas and reaction products, and if these reach the vacuum pump such as the dry pump, the suction capacity will decrease. As corrosion of various parts progresses and reaction products adhere to the piping system, the conductance decreases, so it is common practice to install a trap device in the middle of the exhaust route.

The above-mentioned trap device has, for example, cooling fins, etc., and cools the exhaust gas near the processing temperature within the trap device, causing reaction products in the exhaust gas to adhere to the above-mentioned cooling fins, etc. This device removes harmful substances by reacting or condensing unreacted substances in the gas and depositing them on cooling fins, etc.

In such a trap device, if the amount of captured substances such as reaction products exceeds a certain amount, the efficiency of removing harmful substances from exhaust gas will decrease, so the inside of the device must be cleaned after a certain period of time. There is a need.

In cleaning the trap device described above, after removing the trap device installed by a flange or the like in the middle of the exhaust system piping, internal cleaning is performed at a location where safety is considered.

This is because the captured substances contain toxic substances such as unreacted arsenic.

(Problem to be Solved by the Invention) However, as mentioned above, although cleaning the inside of the trap device itself takes safety into consideration for human bodies, etc., when removing the trap device from the exhaust system piping,
There is a drawback that there is a high possibility that harmful substances may be scattered from the flange portion, etc., and there has been a strong desire to improve safety when removing the trap device from the exhaust system.

In addition, since the trap device is placed in the work area like the heat treatment device, if harmful substances are scattered when the trap device is removed as described above, the scattered substances may cause a decrease in the manufacturing yield of semiconductor devices, etc. There was also the problem that.

The present invention has been made to address these issues, and improves safety by preventing trapped substances from scattering when the trap device is removed from the piping system, and reduces yield loss. The purpose of this invention is to provide a method for cleaning a trap device that prevents the generation of dust, which is a contributing factor.

[Structure of the Invention] (Means for Solving the Problems) That is, the trap device cleaning method of the present invention includes:
When cleaning a trap device that is inserted into an exhaust system and captures harmful substances contained in gases flowing through the exhaust system, an organic solidifying agent is injected into the trap device to solidify the captured material. After that, the trap device is removed from the exhaust system, and the captured material is processed together with a solidifying agent.

(Function) In the trap device cleaning method of the present invention,
Before removing the trap device from the exhaust system, an organic solidifying agent is first injected into the trap device to solidify the captured material, so when the trap device is removed from the exhaust system, the captured material may be scattered. It can be prevented.

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

FIG. 1 is a sectional view showing a schematic configuration of a trap device to which the cleaning method of the present invention is applied.

In the trap device shown in the figure, by airtightly sealing the open surface 2a of the storage body 2, which has a container shape with the − surface 2a open, with the lid 3, a device main body 4 in the form of a casing is formed. It is configured.

An inlet side connection pipe 5 is installed on the lid 3, and the inlet side connection pipe 5 and the exhaust system pipe 6 are removably connected by a flange portion 7. In addition, on the bottom surface 2b of the storage body 2, which faces the open surface 2a,
An outlet side connection pipe 8 is installed, and the outlet side connection pipe 8 and the exhaust system pipe 6 are removably connected by a flange portion 9.

A water cooling jacket 10 is housed in the housing 2 so as to be substantially parallel to the lid 3.

In other words, the water cooling jacket 10 obstructs the path of the exhaust gas sucked from the inlet side connection pipe 5, in other words, leaves a part of the exhaust gas passage (indicated by arrow A in the figure). It is installed so as to occupy the inner area of the storage body 2. Further, the water cooling jacket]0 has a large number of cooling fins 11 protruding from both sides thereof, which come into contact with the exhaust gas sucked from the inlet side connecting pipe 5.

Furthermore, a cooling water introduction and discharge pipe 12 connected to the water cooling jacket 10 passes through the lid 3 and is led out of the apparatus main body 4. That is, the water cooling jacket 10
and the lid body 3 means that the cooling water introduction and discharge pipe 12 is connected to the lid body 3.
It is integrated by being fixed to.

A solidifying agent injection port 13.14 is installed near the center of the bottom surface 2b and the lid 3 of the storage body 2, and these injection ports 13.14 are connected to the pulp 15 attached to each. .16, it is normally possible to close the container airtightly.

The trap device 1 having the above-described configuration is inserted, for example, in the middle of the exhaust system 30 of the heat treatment device 20, as shown in FIG.

That is, the heat treatment apparatus 20 includes a cylindrical reaction vessel 22 that accommodates a plurality of semiconductor wafers 2 as objects to be processed.
and a heating heater 23 arranged to surround it.
A gas introduction pipe 24 for a reactive gas or the like is installed inside the reaction vessel 22. Furthermore, an exhaust system 30 is connected to the lower part of the reaction vessel 22, which is capable of evacuating the inside of the reaction vessel 22 to a predetermined reduced pressure state.

The exhaust system 30 is configured by connecting a vacuum pump such as a dry pump 31 and the reaction vessel 22 with an exhaust system piping 33 (6) in which a main valve 32 is inserted. The trap device 1 is installed in the middle of the piping 33 using flanges (7, 9) or the like.

In addition, around the piping 33 on the upstream side of the trap device 1,
A heating mechanism 34 is installed in this pipe 33 in order to prevent substances contained in the exhaust gas from adhering to the pipe 33 before reaching the trap device 1 .

Next, the method for cleaning the trap device 1 described above will be explained in a third manner.
This will be explained with reference to the figures.

First, for example, after a plurality of semiconductor wafers 2 are placed in a preheated reaction vessel 22, the inside of the reaction vessel 22 is evacuated to a predetermined reduced pressure state using a dry pump 3, and the temperature is raised to a predetermined processing temperature. While heating and evacuation to maintain a predetermined degree of vacuum, process gas such as SiH
2CI2 and HCIH2 are supplied into the reaction vessel 22 from the gas introduction pipe 24, and Si epitaxial growth of the semiconductor wafer 21 is performed.

During this treatment, cooling water is supplied to the water-cooling jacket 10 of the trap device 1 so that harmful substances in the exhaust gas can be captured. As the process progresses, the exhaust gas introduced into the trap device 1 via the exhaust system piping 33 comes into contact with a large number of cooling fins 11 of the water cooling jacket 10, causing unreacted substances contained in the exhaust gas to react or condense. Reaction products, etc. that are attached to the cooling fins 11 or the like or that are eaten directly into the exhaust gas are attached to the cooling fins 11, and harmful substances in the exhaust gas are captured.

When the above operations are repeated, as shown in FIG. 3(a), trapped substances 41 such as reaction products are deposited on the many cooling fins 11 protruding from the water cooling jacket 10, and the cooling The trap device 1 needs to be cleaned because the contact area between the fins 11 and the exhaust gas decreases, resulting in lower trapping efficiency.

To clean the trap device, first, the exhaust system 30 is returned to normal pressure, and then the solidifying agent supply device 42 is connected to each of the solidifying agent inlets 13 and 14. Then valve 15.1
6 is opened, an organic solidifying agent 43 is injected into the apparatus main body 4 from the solidifying agent supply device 42.

The organic solidifying agent to be used should be one that easily separates from the trap body 4 after solidifying, in other words, has excellent mold releasability, has a sufficient expansion coefficient and sufficient ability to capture powder, etc., and is suitable for heating, etc. It is preferable to use a material that can be easily removed by, for example, urethane foam.

The injected solidifying agent 43 is transferred to the device main body 4 of the trap device 1.
Inside, the captured substance 41 is solidified together with the water cooling jacket 10 and the cooling fins 11 so as to cover the captured substance 41 (FIG. 3-a).

After the solidifying agent is sufficiently solidified, the inlet side connecting pipe 5 and the outlet side connecting pipe 8 are separated from the exhaust system piping 6 from the flange 7.9, and the entire trap device 1 is removed from the exhaust system piping 6 ( Figure 3-b).

At this time, since the captured substances 41 such as reaction products captured by the water cooling jacket 10 and the water cooling fins 11 are covered with the solidifying agent 43, even when removed from the exhaust system piping 6, the flange portion 7. No scattering from the open part 9.

The trap device 1 removed from the exhaust system piping 6 is transported to a place where safety is taken into consideration, and then the lid body 3 is moved to the storage body 2.
By removing the water, cooling jacket 10 and cooling fins 11 from the container 2 along with the lid 3, the captured substances 41 attached to the water cooling jacket 10 and cooling fins 11 and covered with the solidifying agent 43 are removed. is taken out from the container 2 (Fig. 3-).

Thereafter, the trapped substance 41 covered with the solidifying agent 43 taken out from the container 2 is treated with the solidifying agent 43 by heat treatment or the like, and is removed from the water cooling jacket 10 and the cooling fins 11 to form the trap device 1. Clean or finish.

In this way, 4 units of captured substances such as reaction products are transferred to 43 units of solidifying agent.
Since the trap device 1 is removed from the exhaust system piping 5 after being covered with the trap device 1, the captured substance 41, which is a harmful substance, will not be scattered from the open part of the flange portion 7.9 when the trap device 1 is removed. . Therefore, safety when removing the trap device 1 can be sufficiently ensured. Further, since the captured substance 41 is not scattered, the manufacturing yield of semiconductor wafers is not reduced.

In addition, the water cooling jacket 10 was removed from the removed trap device.
Even when the captured material 41 is pulled out together with the cooling fins 11, the captured material 41 does not scatter.
1 can be processed more safely.

In the above embodiments, the method of the present invention is applied to cleaning a trap device inserted in the exhaust system of a batch-type heat treatment apparatus, but the present invention is not limited to this, and for example, It can also be applied to cleaning a trap device inserted in the exhaust system of a sheet-format CVD device, a resist coating device, etc., and the same effect as in the above embodiment can be obtained, such as reduction of scattered substances.

[Effects of the Invention] As explained above, according to the method of cleaning the tiger knob device of the present invention, it is possible to prevent the captured material from scattering, so that when removing the trap device or disposing of the captured material, it is possible to prevent the captured material from scattering. The safety of the process can be sufficiently ensured, and there is no generation of dust, etc., which can cause a decrease in the production yield of the workpiece.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the configuration of a trap device to which the method of the present invention is applied, FIG. 2 is a diagram showing an example of use of the trap device shown in FIG. 1, and FIG. 3 is a cross-sectional view of the trap device shown in FIG. 1. It is a figure showing the cleaning process of. 1... Trap device, 2... Storage body,
3...Lid body, 4...Device main body, 5...
...Inlet side connection piping, 6.33...Exhaust system piping, 7.9...Flange section, 8...
・Outlet side connection piping, 10...Water cooling rack, 11...Cooling fin, 13.15...
...Solidifying agent inlet, 15.16...Valve 1
4.15.20...Heat treatment equipment, 30...
...Exhaust system, 31...Dry pump, 41...
... Captured substance, 42 ... Solidifying agent supply device, 4
3...Organic solidifying agent.

Claims (1)

[Scope of Claims] When cleaning a trap device that is inserted into an exhaust system and captures harmful substances contained in gas flowing through the exhaust system, an organic solidifying agent is injected into the trap device, A method for cleaning a trap device, comprising: solidifying the captured material, removing the trap device from the exhaust system, and treating the captured material together with a solidifying agent.