JPH07161656A - Heat-treating device - Google Patents

Abstract

PURPOSE:To reduce the adverse effect of an impurity, which is scattered from a dust-removing filter part, in a heat-treating device of a structure, wherein an air flow is formed within a transfer chamber through a vent path for circulation provided with the dust-removing filter part. CONSTITUTION:A circulating duct part 4 arranged with a blowing fan 43 and a shutter S is provided so as to form an air flow within a transfer chamber 3 on the side of the lower part of a heat-treating furnace 2 and a dust-removing filter part 5 is provided in a blow-off port of the duct part 4. Moreover, three air feed pipes 60 to 62, for example, which are formed with a multitude outlet holes 60, are respectively provided at a position of a prescribed height on the side of the front of this filter part 5 and a clean gas feed source 64 is connected to the side of a base end of these pipes via an on-off valve 63. After an unloading of wafers W is started, clean gas from the source 64 is circulated in the chamber 3 while the wafers W are detached from a wafer boat 32 and the circulation of the air flow in the chamber 3 is kept stopped.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a heat treatment apparatus.

[0002]

2. Description of the Related Art A semiconductor wafer manufacturing process includes heat treatment steps such as film forming treatment, oxidation treatment, and diffusion treatment. However, as a heat treatment apparatus for performing such heat treatment in a batch system, it is less likely to involve air. Vertical heat treatment equipment has become widespread because of its advantages.

In this vertical heat treatment apparatus, as shown in FIG. 7, a transfer chamber 12 which forms a working space below the vertical heat treatment furnace 11 is provided.
And a wafer boat 13 that moves up and down between the transfer chamber 12 and the heat treatment furnace is provided. Regarding the operation, after the wafers W are vertically placed on the wafer boat 13 in a rack shape, the boat boat 14 carries the wafer boat 13 into the heat treatment furnace 11 to perform a predetermined heat treatment, and then the wafer boat 13 is The wafer W is carried out and taken out from the wafer boat 13.

In this heat treatment apparatus, in order to prevent particles existing in the atmosphere and particles generated during transfer of the wafer W from adhering to the wafer W, a dust removal filter section 15 is provided from a circulation ventilation passage (not shown). The purified air is allowed to flow into the transfer chamber 12 through.

[0005]

The filter part 15 is formed by bending the filter paper into a bellows shape and fixing the upper and lower sides and both sides of the filter paper to a frame member with an adhesive. The filter part 15 is carried out from the heat treatment furnace. Since the processed wafer W is in a high temperature state, the radiant heat from the wafer W causes the filter portion 1 to
5 is heated to a high temperature, and an organic component such as hydrocarbon is scattered from the adhesive used in the filter portion 15, for example, an epoxy resin. Then, this organic component reacts with the film formation layer of the semiconductor wafer at a high temperature to deteriorate the electrical characteristics and film performance of the film formation layer and lowers the yield. In particular, this influence is more than 16 MDRAM (random access memory). Remarkably large in processing.

Further, the filter paper used in the filter section 15 contains impurities such as boron (B), and when the filter paper is heated to a high temperature, the amount of scattered boron etc. increases and the device pattern is changed. As it becomes finer, impurities from the filter paper also greatly affect the yield.

The present invention has been made under the circumstances as described above, and its purpose is to provide an object to be processed in a transfer chamber,
An object of the present invention is to provide a heat treatment apparatus capable of reducing the adverse effects of impurities scattered from the dust removal filter section.

[0008]

According to a first aspect of the present invention, the object to be processed is held by the object-to-be-processed holder and is carried in and out from the transfer chamber into the reaction tube, and the suction port and the blowing port are moved. In a heat treatment apparatus that circulates the gas in the transfer chamber through a circulation air passage that is open to the mounting chamber and is equipped with a dust filter section, a clean gas supply source and the clean gas from this source are supplied to the dust filter section. A supply passage for supplying the transfer chamber without passing through, and an on-off valve provided in this supply passage,
Switching of the ventilation mode is controlled between a first mode in which the opening / closing valve is opened and ventilation in the circulation ventilation passage is stopped and a second mode in which the opening / closing valve is closed and ventilation in the circulation ventilation passage is performed. And a control unit.

According to the second aspect of the present invention, the object to be processed is held by the object-to-be-processed holder and is carried into and out of the reaction tube from the transfer chamber, and the suction port and the blowing port are opened in the transfer chamber. In a heat treatment apparatus that circulates gas in a transfer chamber through a circulation air passage provided with a dust removal filter section, at least after carrying out the object-to-be-processed holder from the reaction tube and taking out the object-to-be-processed from the object-to-be-treated holder A control unit is provided to control so as to stop the ventilation of the circulation air passage during the period.

[0010]

According to the first aspect of the invention, for example, the circulation of gas using the circulation ventilation passage is stopped from the start of unloading after the heat treatment of the object to be processed until the next object is loaded. Clean gas is supplied into the transfer chamber without passing through the dust removal filter section to form an air flow. While the object to be treated is stored in the reaction tube, gas is circulated between the ventilation passage for circulation and the transfer chamber, and the gas from the dust filter section forms an air flow to remove particles in the transfer chamber. . Therefore, even if the dust removal filter section is heated by receiving radiant heat from the heat-treated object, adhesion of organic components and the like from the filter section to the object is suppressed.

According to the second aspect of the present invention, the influence of impurities from the dust removing filter portion is reduced by stopping the circulation of the air flow without passing the clean gas at a predetermined time.

[0012]

FIG. 1 is a vertical sectional side view showing an embodiment in which the present invention is applied to a vertical heat treatment apparatus, and FIG. 2 is a perspective view showing the whole structure of the vertical heat treatment apparatus. Reference numeral 2 in the drawing denotes a vertical heat treatment furnace, which is composed of a reaction tube and a heater provided around the reaction tube, although the inside is not shown. A transfer chamber 3 forming a working space is formed below the heat treatment furnace 2, and the heat treatment furnace 2 and the transfer chamber 3 are surrounded by a housing 20.

The transfer chamber 3 is provided with a boat elevator 31 which is an elevating mechanism, and a wafer boat 32 which is a wafer holder is placed on the boat elevator 31. The wafer boat 32 is configured so that the wafers W are vertically mounted in a rack shape, and is loaded into and unloaded from the heat treatment furnace 2 by the boat elevator 31.

On the front side of the transfer chamber 3, a wafer carrier (hereinafter referred to as “carrier”) mounting table 21 that serves as a wafer transfer section is arranged, and on the front side of the carrier mounting table 21, the carrier is placed. A carrier input / output port 23 is provided via the transfer area of the transfer mechanism 22. A wafer transfer mechanism 22 is arranged between the carrier mounting table 21 and the boat elevator 31, and a carrier stocker 24 is installed above the carrier mounting table 21.

On both side walls of the transfer chamber 3, there are formed gas inlets and outlets, respectively, which serve as gas inlets and outlets, and the air inlets on the inlet side are made of, for example, a metal plate having many minute holes. An airflow regulating plate 41 is provided.

On both side walls of the transfer chamber 3 and on the lower side of the bottom surface of the transfer chamber 3, a circulation duct portion 4 forming a ventilation passage is formed. A shutter S for opening and closing the ventilation path by the opening / closing mechanism 42 and a blower, for example, a first blower fan 43 are provided on the lower side of the circulation duct part 4 such as the transfer chamber 3, and the outlet of the duct part 4 is blown out. Is provided with a dust removal filter portion 5 formed by bending a filter paper in a bellows shape, for example.

An exhaust duct portion 44 is provided in a branched manner on the upstream side of the first blower fan 43 in the circulation duct portion 4, and a second blower fan 45 is arranged in the exhaust duct portion 44. The exhaust side is connected to the factory exhaust duct.

The front side (right side in FIG. 1) of the dust-removing filter portion 5 has the upper end portion, the central portion and the lower end portion as shown in FIG.
And, as shown in FIG. 3, air supply pipes 60, 61, 62, respectively.
Is laid along the width direction of the dust filter unit 5,
On the wafer boat 32 side of these air supply pipes 60 to 62, a large number of air outlets 6 are formed along the pipe lines. In this embodiment, the air supply pipes 60 to 62 form a clean gas supply path, and are connected to a common clean air supply source, for example, a clean air cylinder, via an opening / closing valve 63.

Further, in this embodiment, a control section 7 for switching and controlling the ventilation mode in the transfer chamber 3 is provided. The control unit 7 includes a shutter S opening / closing mechanism 42, a first
Blower fan 43, second blower fan 45, and on-off valve 6
3 to control clean air from the clean air supply source 64 into the transfer chamber 3 and exhaust it from the exhaust duct part 44, and the transfer duct 3 using the circulation duct part 4. It has a function of controlling switching between the second mode of circulating the air and the second mode at a predetermined timing.

Next, the operation of the above embodiment will be described.
First, a carrier C containing 25 objects to be processed, for example, wafers.
Is a carrier input / output port 23 by a carrier device (not shown).
The carrier C is mounted on the carrier transfer mechanism 22.
Are transferred to the carrier mounting table 21. Next, in the transfer chamber 3, the carrier transfer table 21 is moved by the wafer transfer mechanism 24.
Wafers W are transferred from the upper carrier C to the wafer boat 32, and the wafer boat 32 has, for example, 100 wafers W.
Are held up and down like shelves.

After that, the wafer boat 32 is loaded into the heat treatment furnace 2 from the transfer chamber 3 by the boat elevator 31. And the heat treatment furnace 2 is, for example, about 800 in advance.
The wafer W is heated to a temperature of .degree. C., and after the wafer W is loaded, the wafer W is heated to a predetermined temperature, for example, a temperature of 1000.degree. Wafer boat 32 after a lapse of a predetermined time
Is carried out to the transfer chamber 3 by the boat elevator 31, and the wafer W on the wafer boat 32 is transferred by the wafer transfer mechanism 22.
Are taken out and transferred into the carrier C on the carrier table 21.

The air ventilation mode in the transfer chamber 3 and the above-described steps will be described in correspondence with each other with reference to FIG. 4. For example, the step of transferring a wafer to the wafer boat 32 and loading the wafer will be described. In the process (loading) and the process in which the heat treatment is performed, the control unit 7 selects the second mode, that is, the air circulation mode. In the second mode, the first blower fan 43 is turned on, the second blower fan 45 is turned off, the opening / closing valve 63 is closed, and the shutter S is opened, so that the transfer chamber 3 is Of the air from the air flow regulating plate 41 in the transfer chamber 3 in the circulation duct section 4 of FIG.
It is sucked into the inside right side surface part, and is sent to the left side surface part in FIG. 1 of the transfer chamber 3 through the lower passage of the bottom surface of the transfer chamber 3. Then, this air is sent through the dust removal filter section 5 into the transfer chamber 3 after particles are removed therein, and thus the air circulates to form an air flow in the transfer chamber 3 and to the wafer W. Prevents the particles from adhering.

When the heat treatment process is completed and the unloading process is started, the controller 7 operates in the first mode, that is, the clean air supply, from this point until the removal of the wafer W from the wafer boat 32 is completed. Select a mode. In the second mode, the first blower fan 43 is turned off, the second blower fan 45 is turned on, the opening / closing valve 63 is open, the shutter 40 is closed, and the clean air supply source 64 is provided.
Clean air is sent to the air supply pipes 60 to 62, and is supplied into the transfer chamber 3 through the blowout holes 6 of the air supply pipes 60 to 62. This air enters the space on the back side (a part of the circulation duct part 4) via the air flow restricting plate 41, and is exhausted from the exhaust duct part 44 to the factory exhaust duct by the second blower fan 45.

According to such an embodiment, even if the wafer W is unloaded and the dust removing filter section 5 is heated to a considerably high temperature by the radiant heat from the high temperature wafer W, the circulation duct section 4 is stopped from flowing. Since clean air is supplied from the clean air supply source 64 into the transfer chamber 3 without passing through the dust removal filter unit 5 to form an air flow, impurities such as boron from the filter paper of the dust removal filter unit 5 and adhesives Particles generated in the transfer chamber 3 can be discharged while preventing the organic components of the above from being scattered into the transfer chamber 3. As a result, the particles adhere to the wafer W and the impurities from the dust removal filter unit 5 Adhesion can be prevented.

After the wafer W is taken out from the wafer boat 32, air is circulated through the circulation duct section 4 to form an air flow in the transfer chamber 3, and the clean air supply source 64 is used only when necessary. Therefore, the cost increase can be suppressed. The clean air supply mode may be selected at the time of transferring and loading the wafer W on the wafer boat 32 in addition to the above steps.

In the present invention, the clean air does not always have to be supplied from the clean air supply source when the circulation of the air in the transfer chamber 3 is stopped. FIG. 5 and FIG. 6 are views showing such an embodiment, in which the control unit 8 turns on the blower fan 43 during the transfer of the wafer to the wafer boat 32, the loading and the heat treatment process, unloading, and During the process of taking out the wafer from the wafer boat 32, the blower fan 43 is turned off to stop the flow of air in the dust removal filter section 5. In such an embodiment, even if the dust removing filter portion 5 is heated by the radiant heat of the wafer W, air does not flow through the dust removing filter portion 5, so that the scattering of boron and organic components from the filter portion 5 can be suppressed and the wafer W can be prevented. It is possible to prevent adverse effects.

In the above, in the present invention, when the clean air is made to flow into the transfer chamber 3 in the clean air supply mode (first mode), for example, the air is supplied to the rear side of the device in the overall view of the device in FIG. A tube may be provided. Further, the air flow in the transfer chamber 3 is not limited to air, and for example, the transfer chamber 3 may be a load lock chamber and may be formed of nitrogen gas or the like. The present invention is
The present invention can be applied not only to the oxidation treatment but also to a batch type heat treatment apparatus such as a diffusion treatment, a CVD treatment and an etching treatment.

[0028]

As described above, according to the present invention, in the heat treatment apparatus for forming the air flow in the transfer chamber through the circulation air passage having the dust removing filter portion, the ventilation by the circulation air passage is stopped as necessary. Instead, the clean gas is supplied from a separate clean gas supply source to the transfer chamber without passing through the dust removal filter section (invention of claim 1), or the clean gas is not supplied but is circulated. Since the ventilation through the ventilation passage is stopped as necessary (the invention of claim 2), even if the dust filter section is heated by the radiant heat of the object to be treated after the heat treatment, the adverse effect of the impurities scattered from the dust filter section is prevented. It can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing an overall configuration of a vertical heat treatment apparatus according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a main part of an embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a relationship between a processing step and an air flow forming mode.

FIG. 5 is a vertical sectional view showing another embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a relationship between a treatment process and an air flow forming mode according to another embodiment of the present invention.

FIG. 7 is a schematic sectional view showing a conventional heat treatment apparatus.

[Explanation of symbols]

 2 Heat treatment furnace 21 Wafer carrier mounting table 3 Transfer chamber 32 Wafer boat 4 Circulation duct part 42 Shutter opening / closing mechanism S Shutter 43, 45 Blower fan 5 Dust filter part 60-62 Air supply pipe 63 Open / close valve 64 Clean air supply source W Semiconductor Wafer

Claims (2)

[Claims] 1. An object to be processed is held by an object-to-be-processed holder and carried in and out from a transfer chamber to and from a reaction tube, and a suction port and a blowing port are opened to the transfer chamber and a dust removal filter section is provided. In a heat treatment apparatus that circulates gas in the transfer chamber through the circulation ventilation passage, a clean gas supply source and a clean gas from the supply source are supplied to the transfer chamber without passing through the dust filter section. A supply path, an opening / closing valve provided in the supply path, a first mode in which the opening / closing valve is opened and ventilation of the circulation ventilation path is stopped, and the opening / closing valve is closed and ventilation of the circulation ventilation path is performed. A heat treatment apparatus comprising: a control unit that controls switching of the ventilation mode between the second mode and the second mode. 2. An object to be processed is held by an object-to-be-processed holder and carried into and out of a reaction tube from a transfer chamber, a suction port and a blow-out port are opened to the transfer chamber, and a dust removal filter section is provided. In the heat treatment device that circulates the gas in the transfer chamber through the circulation ventilation path, at least until the object to be processed is removed from the reaction tube after the object to be processed is taken out from the reaction tube. A heat treatment apparatus comprising a control unit for performing control so as to stop ventilation of an air passage.