JPH0259002A - Trap device - Google Patents

Abstract

PURPOSE:To enable reaction products to be trapped at high accuracy for a long period of time by providing a cooling mechanism to cool exhaust gases gnd a gas passage having a construction such that the exhaust gases are caused to run against the surface of a wall a plurality of times. CONSTITUTION:Exhaust gases flow through a gas inlet 19 of a trap device 17, pass through a gap 26, and flow into an inner cylinder through an opening 30, whereby the exhaust gases are cooled, while passing through the gap 26, so that some of the reaction products are caused to stick to the surface of the wall in a state of mist, while the cooled exhaust gases pass through holes 34 of discs 33a and flow toward a gas outlet 20, wherein the exhaust gases flow straight through the holes 34, but, since discs 33b are provided, they run against the walls thereof so that the reaction products in the gases are caused to stick to said walls, while the gases having run against the walls run against the inner wall of the inner cylinder, where the reaction products also stick to said inner wall. Further, the exhaust gases pass through the toles 34 and thereafter run against the next disc 33b, whereby a plurality of collisions of gases are effected and the gases are discharged from the outlet 20 through openings 35, while inside the cylinder, the gases are cooled since the side wall thereof is cooled.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an l-wrap device.

(Prior Art) A heat treatment apparatus equipped with a processing container, that is, a reaction tube, is used in a heat treatment process of an object to be processed, such as a semiconductor wafer, that is, an oxidation process, a diffusion process, a CVD process, etc.

In this heat treatment equipment, a quartz reaction tube is set in a heater wrapped with a heating wire that can freely generate heat, and a boat carrying a plurality of wafers is inserted from the open end of the reaction tube.
After setting the wafer at a predetermined position in the reaction tube, the opening end is sealed with a lid, and heat treatment is performed by introducing a predetermined processing gas while the wafer is heated by the heat generated by the heater wire. be. Such heat treatment techniques include, for example, Japanese Patent Publication No. 60-41848 and Japanese Patent Application Laid-open No. 60-11.
It is disclosed in Japanese Patent No. 9716 and the like.

In this kind of heat treatment, the treated exhaust gas inside the reaction tube is exhausted to the outside, but this exhaust gas contains reaction products, and if it is exhausted as it is, the above products will get mixed into the oil of the vacuum pump. This will cause the oil in the lever to deteriorate. Due to the deterioration of this oil, the exhaust capacity inside the reaction tube decreases, making it impossible to set the inside of the reaction tube to the desired pressure and performing the desired heat treatment. A trap device is provided to trap reaction products in this exhaust gas. This trap device uses, for example, a technique in which reaction products are deposited in the form of a mist and removed by causing exhaust gas to flow through a gas flow path provided with a mesh-like filter.

Further, a technique for removing unreacted gas from the exhaust gas is disclosed in Japanese Patent Application Laid-Open No. 61-291033.

(Problems to be Solved by the Invention) However, with the technology using the mesh-like filter, the mesh is severely clogged, and the mesh needs to be replaced frequently, which is very time-consuming and reduces the operating efficiency of the heat treatment equipment. There was a problem that caused it to deteriorate. Furthermore, when the mesh filter is provided, there is a problem in that the conductance of the exhaust gas becomes low and the exhaust efficiency decreases.

Also, disclosed in Japanese Patent Application Laid-Open No. 61-291033,
Although it is possible to remove the unreacted gas by heating the exhaust gas to cause the unreacted gas to react and adhere to the fin surface, most of the reaction products do not adhere to the fins and may pass through. Resulting in. As a result, the reaction products cannot be removed and are exhausted, mixing with the oil of the vacuum pump and contaminating this oil, or the mechanical booster pump being clogged with the reaction products, causing a lock-up image and making exhaustion impossible. There was a problem with it. If the oil becomes contaminated, the performance of the vacuum pump deteriorates, and the operating rate of the heat treatment apparatus decreases due to frequent oil changes.

Furthermore, since the exhaust gas is heated to 500° C. or higher, there is a risk of high temperatures, and therefore it is necessary to take measures against high temperatures on the vacuum pump side, resulting in high costs.

The present invention has been made in response to the above-mentioned problems, and aims to provide a trap device that can trap reaction products with high precision and a long life.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a trap device for removing reaction products contained in exhaust gas exhausted from a processing container, including a cooling mechanism for cooling the exhaust gas, and a plurality of cooling mechanisms for cooling the exhaust gas on a wall surface. The present invention provides a trap device characterized by having a gas flow path structured to cause multiple collisions.

(Operations and Effects) That is, 1 the present invention is provided with a cooling mechanism that cools the exhaust gas exhausted from the processing chamber and a gas flow path structured to cause the exhaust gas to collide with the wall surface multiple times, so that the reaction products are cooled. It becomes a mist, and by attaching this mist to the wall surface of the gas flow path, it is possible to trap the reaction products. At this time, the reaction products adhere to the wall surface of the gas flow path because the gas flow path has a structure that causes the exhaust gas to collide with the wall surface multiple times, so the exhaust gas is forced to collide with the wall surface and adhere to the wall surface. be. Such collision of the exhaust gas against the wall surface has a particularly high trapping ability and can effectively attach the reaction products.

Furthermore, since there is no clogging and the exhaust conductance can be increased, highly accurate exhaust and pressure control can be achieved.

Furthermore, since the exhaust gas is cooled, dangers due to high temperatures can be prevented.

(Example) Hereinafter, an example will be described in which the apparatus of the present invention is applied to epitaxial growth processing in a semiconductor manufacturing process.

This will be explained with reference to the drawings.

First, the configuration of the epitaxial growth apparatus will be explained.

This apparatus is a vertical epitaxial growth apparatus, as shown in FIG. For example, a support such as a boat (A) on which a plurality of semiconductor wafers (2), for example, about 20 to 50 semiconductor wafers (2) are loaded at predetermined intervals in the vertical direction, and this boat (A) are placed in a predetermined position below the reaction tube (2). Boat received (a)
It consists of a transport mechanism (c) that loads and unloads the reaction tube from the delivery position to the reaction tube (c).

The reaction tube of the processing section (1) is made of a non-metallic material, such as quartz glass, which is heat resistant and does not easily react with the processing gas, and has a cylindrical structure with the upper end sealed. This reaction tube (1) has a double tube structure, and a cylindrical inner tube (1a) made of a non-metallic material such as quartz glass and sealed at the upper end is placed inside the reaction tube (ω). provided in contact. The inner surface of the reaction tube (■) and the inner tube (1a)
) is provided with a gap 0 of a predetermined distance, for example, 17 mm, between the side wall of the inner tube (1a) and the outer surface of the inner tube (1a), so as to allow ventilation between this gap and the inside of the inner tube (1a). A plurality of gas vent holes (2) are provided at predetermined positions. The gap 0 is removably sealed at its lower end by a tubular manifold (8) made of, for example, SUS. This manifold ■ holds an upper manifold (8a) that holds the outer reaction tube ■ and an inner inner tube (1a), and the inner tube (1a) can be easily installed and removed during maintenance and assembly. Lower manifold (for
8b), and each joint is kept airtight by a sealing material such as an O-ring (9). In addition, a plate-shaped lid body (10
) is provided. A sealing member such as an O ring 0 is provided at the contact portion of the lid body (10) with the manifold (8b), so that the interior of the inner tube (1a) and the reaction tube ω can be kept airtight. There is. Further, an inlet pipe (11) for introducing processing gas and carrier gas is provided which extends into the inner pipe (1a) through the manifold (8b).

This gas introduction pipe (11) extends vertically along the inner surface of the inner pipe (1a), and has a plurality of openings (lla) at positions corresponding to each wafer (2) loaded on the boat (a). The processing gas can be supplied to the wafer (1) through this opening (lla). In addition, the above lid body (10
) is provided with a support (12) whose surface is coated with a non-metallic material such as quartz glass. This support body (12) is connected to a stand (14) by a heat-insulating cylinder support made of stainless steel (SO5) provided on the bottom surface of the heat-insulating cylinder (13), and is attached to the heat-insulating cylinder (13) and the boat. It is configured to support. The above heat insulation tube (13
) is a cylindrical body made of a non-metallic material, such as quartz glass, and is provided to prevent the heat in the reaction tube (g) from escaping downward. At the upper end of this heat insulating cylinder (13), the above-mentioned boat O
) are arranged in series, and have a structure that is linked to the vertical movement of the lid body (10) by the transport mechanism (2). Further, a cylindrical heating mechanism, for example, a heater (15) wound in a coil shape, is provided so as to coaxially surround the reaction tube, and this heater (15) covers the inside of the area where the wafer (2) is placed. It is provided so as to uniformly heat to a desired temperature, for example, about 600 to 1400°C. In order to heat the region on which the wafer (1) is placed by the heater (15) with a more uniform temperature distribution, for example, a silicon carbide (SiC) is placed between the heater (15) and the outer wall of the reaction tube (2). A soaking tube (not shown) made by Baite) is installed. Further, an exhaust pipe (16) is connected to the manifold (8a) to exhaust the atmosphere in the gap 0 and the atmosphere in the inner tube (1a), and this exhaust pipe (16) is equipped with a trap! (17
) is connected to a vacuum pump such as a mechanical booster pump (18a) and a rotary pump (18b).

As shown in FIG. 2, the trap device M (17) has a cylindrical structure and has a gas inlet (19) for introducing exhaust gas into the interior.
The mechanical booster pump (18a) is provided with a gas outlet (20) which is connected to the exhaust pipe (16) and which leads out the exhaust gas from inside the trap device (17).
) and the rotary pump (18b). This trap device (17) is provided with a cooling mechanism that cools the exhaust gas introduced into the interior, and a gas flow path configured to cause the exhaust gas to collide with the wall surface multiple times.

This makes it possible to cool the exhaust gas by circulating cooling water whose temperature is controlled to a predetermined temperature, for example, 20° C., through a gap (21) provided inside the wall of the cylindrical trap device (17).

That is, the cooling water inlet (2) connected to the gap (21)
2), cooling water cooled to a predetermined temperature is introduced and circulated. Then, the trap device (17
) and a predetermined distance, for example, by 3 m, to create a non-contact state.
An inner cylinder (23) is provided. This inner cylinder (23) is
It can be inserted into the trap device (17) and has a structure that allows easy maintenance, such as internal cleaning. This inner cylinder (23) is connected to the trap device (
17) When installed inside, the upper end of the inner cylinder (23) comes into contact with the sealing member (24), and the lower end comes into contact with the lid (25).
), the inner cylinder (
23) and the gap (26) between the inner walls of the trap device (17) are airtightly provided. In addition, the exhaust gas can be cooled by circulating cooling water whose temperature is controlled to a predetermined temperature, for example, 20°C, through the gap (27) provided inside the wall of the inner cylinder (23). Cooling water cooled to a predetermined temperature is introduced and circulated through a cooling water inlet (28) and a cooling water outlet (29) connected to the cooling water inlet (27). Such an inner cylinder (23) has an opening (30).
is provided, and the exhaust gas introduced from the gas inlet (19) and further channeled through the gap (26) enters the opening (
30) and is introduced into the inner cylinder (23). At this time, the introduced exhaust gas is transferred to a gap (21) provided inside the wall of the trap device (17).
and a gap (27) provided inside the wall of the inner cylinder (23).
In order to increase the cooling time, that is, the distance that the exhaust gas contacts the wall surface, for example, the gas inlet (19) is provided above the side surface of the trap device (17). Further, the opening (30) is provided below the side surface of the inner cylinder (23). Furthermore, by providing a partition plate (31) in the gap (26) through which the exhaust gas flows, the exhaust gas flows in a spiral shape and the contact distance is increased. Further, a rod (32) extending downward from the center of the earthen wall of the inner cylinder (23) is provided.
2), a plurality of discs (33a) (33b) are attached at predetermined intervals, for example, 50 fields. This disk (33a) has a diameter somewhat smaller than the inner diameter of the inner tube (23), and is provided with a plurality of, for example, four, vent holes (34). For example, as shown in FIG. 3, they are formed with a pitch of 90 degrees and a diameter of, for example, 40 an. Further, the disc (33b) is formed to have a smaller diameter than the disc (33a), and six such discs (33a) and six discs (33b) are arranged alternately. Further, a plurality of openings (35) are provided on the upper surface of the inner cylinder (23) in the same manner as described above, and the trap device it (17) is passed through the openings (35).
) The structure is such that exhaust gas flows out from a gas outlet (20) provided on the upper wall of the exhaust gas. This is how you set up a trap!
(17) and an epitaxial growth apparatus are constructed.

Next, the operation of the above-mentioned epitaxial growth apparatus will be explained.

First, a boat (A) loaded with wafers (A) is transferred by a handler (not shown) onto a heat-insulating cylinder (13) set at a transfer position (not shown). and place it. and.

The boat (a) is raised by a predetermined amount by the transport mechanism 0, and the manifold (8b) at the lower end of the reaction tube
By bringing the wafer (10) into contact with the wafer (3), the
② and make the inside of the reaction tube airtight. Next, the inside of the reaction tube σ) is set to a desired low pressure state, for example 1 to
The mechanical booster pump (18a) and rotary pump (18b) are used to control the exhaust to maintain the temperature at 20 Torr, and the heater (15) is used to adjust the temperature to a desired temperature, e.g. 1050°C.
Set to a certain degree. After this setting, while controlling the exhaust gas and adjusting the flow rate from the gas supply source using a mass flow controller (not shown), process gas such as SiH, CQ□
(dichlorosilane) and H2 (hydrogen) are supplied into the reaction tube (1), ie, the inner tube (1a), through the gas introduction tube (11) from a plurality of openings (lla) for a predetermined period of time. Then, on the surface of wafer 0 installed in the reaction tube, SL (
A silicon film is grown epitaxially.

5i82CI22+ H, →Si +2H(j2
(2) During and after this epitaxial growth process, the atmosphere in the reaction tube (2), that is, the exhaust gas, is exhausted from the exhaust pipe (16) through the gas vent hole (2) provided on the side wall of the inner tube (la). . This exhaust gas is
Removal of the contained reaction products takes place in the trap device (17). That is, the above exhaust gas is collected by a trap device (
The gas flows in from the gas inlet (19) of 17), passes through the gap (26), and flows into the inner cylinder (23) from the opening (30). At this time, the exhaust gas is cooled while passing through the gap (26), and some reaction products adhere to the wall surface in the form of mist. Then, this cooled exhaust gas is transferred to a disk (3
3a) and flows to the gas outlet (20) side. At this time, the exhaust gas passes through the vent (34) and travels straight, but a disk (33b) is present on the straight travel side. Therefore, the exhaust gas collides with the wall surface of this disk (33b), and reaction products in this exhaust gas adhere. The collided exhaust gas then collides with the inner wall surface of the cylinder (23), and reaction products adhere here as well. Furthermore, this exhaust gas passes through the vent hole (34) of the disc (33a) and collides with the next disc (33b) in the same manner as above. Such a collision of exhaust gas occurs multiple times, and the gas exit (20) passes through the opening (35) provided in the earthen wall of the inner cylinder (23).
is exhausted from. Also inside the inner cylinder (23), the exhaust gas is cooled because the side wall of the inner cylinder (23) is cooled.

In this way, the reaction products can be trapped by cooling and by collision with the wall surface, so most of the reaction products contained in the exhaust gas can be trapped, and the vacuum The pumps, namely the mechanical booster pump (18a) and the rotary pump (18b), are not adversely affected.

Furthermore, the trap device (17) can be regenerated by periodically disassembling and cleaning it. During this disassembly, the inner cylinder (23) can be easily cleaned by simply removing it.

After such epitaxial growth processing, the supply of the processing gas is stopped and an inert gas such as N2 (nitrogen 74) gas or Ar (argon) gas is introduced into the inner tube (1a). ) to return to normal pressure.

Then, a boat (
A) is carried out by the transport mechanism 0 to a transfer position (not shown), and the process is completed.

Although the above embodiment describes cooling of exhaust gas using cooling water, the present invention is not limited to this, and similar effects can be obtained by cooling using, for example, gas or a Peltier element. Furthermore, although the cooling section is provided only inside the wall, a structure may be adopted in which, for example, the disks (33a) (33b) or the rod (32) are cooled.

Further, in the above embodiment, an example was explained in which the trap device was used for epitaxial growth processing of a semiconductor wafer, but the trap device is not limited to this, and may be used for, for example, CVD processing, etching processing, ashing processing, etc. Similar effects can be obtained not only in semiconductor wafers but also in applications such as LCD boards and printed circuit boards used in screen display devices such as liquid crystal TVs.

As described above, according to this embodiment, the reaction products are cooled by being equipped with a cooling mechanism that cools the exhaust gas exhausted from the processing chamber and a gas flow path structured to cause the exhaust gas to collide with the wall surface multiple times. The reaction product becomes a mist, and the reaction product can be trapped by attaching the mist to the wall of the gas flow path. At this time, the reaction products adhere to the wall surface of the gas flow path because the gas flow path has a structure that causes the exhaust gas to collide with the wall surface multiple times, so the exhaust gas is forced to collide with the wall surface and adhere to the wall surface. be.

Such collision of the exhaust gas against the wall surface has a particularly high trapping ability and can effectively attach the reaction products.

Furthermore, since there is no clogging and the exhaust conductance can be increased, highly accurate exhaust and pressure control can be achieved.

Furthermore, since the exhaust gas is cooled, dangers due to high temperatures can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an epitaxial growth apparatus for explaining one embodiment of the apparatus of the present invention, FIG. 2 is an explanatory diagram of the trap device of FIG. 1, and FIG. 3 is an explanatory diagram of the disk of FIG. 2. 1... Reaction tube 3... Wafer 17... Trap device 19... Gas inlet 20... Gas outlet 23... Inner cylinder 33... Disc patent applicant Chill Sagami Co., Ltd. Figure

Claims (1)

[Claims] A trap device for removing reaction products contained in exhaust gas exhausted from a processing container, comprising a cooling mechanism for cooling the exhaust gas and a gas flow path configured to cause the exhaust gas to collide with a wall surface multiple times. Features a trap device.