JP5376819B2 - Heat treatment equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment device that prevents damage from spreading in an emergency state, such as an earthquake and a fire, at low cost. <P>SOLUTION: The heat treatment device 100 includes at least a heater 14, a soft shell portion 161, and a wall portion 162. The heater 14 is disposed at a periphery of a process tube 12, and configured to heat the process tube 12. The soft shell portion 161 and wall portion 162 are configured to form an airtight space airtightly enclosing at least the heater 14. The soft shell portion 161 is configured to vary the capacity of the airtight space according to the internal pressure of the airtight space. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a heat treatment apparatus that performs heat treatment on a workpiece enclosed in a process tube, and more particularly to a heat treatment apparatus devised to prevent damage expansion in an emergency such as an earthquake or a fire at a low cost.

In the heat treatment apparatus, various kinds of gases and vapors are introduced into the process tube when heat treatment is performed on the workpiece enclosed in the process tube. Since gases introduced into the process tube include flammable or explosive dangerous gases such as flammable gases, technologies for preventing leakage of such dangerous gases have been developed in the past. (For example, refer to Patent Document 1). In the technology according to Patent Document 1, the periphery of a raw material tank that stores explosive gas is covered with an airtight casing, and the amount of inert gas supplied into the casing is increased when an ignition or explosion is detected. I try to let them. By adopting such a configuration, the technique according to Patent Document 1 is capable of rapid digestion with an inert gas and can prevent the fire from spreading outside the housing.
JP 2006-156650 A

  However, it is preferable that the heat treatment apparatus is configured not only to prevent leakage of dangerous gas during normal times, but also to prevent expansion of damage in an emergency such as an earthquake or a fire.

  For example, when a process tube for heat treatment on a semiconductor substrate or glass substrate is damaged, the housing is damaged by a sudden pressure change inside the housing, resulting in leakage of dangerous gas from the housing There was a risk of damage spreading due to external oxygen coming into contact with the heat source. Process tubes are made of materials that are relatively easily damaged, such as quartz glass and SiC, to ensure the cleanliness of the product, so it is assumed that process tubes can be damaged in the event of an emergency such as an earthquake or fire. It is necessary to keep it. At this time, it is possible to take a measure that the casing that covers the periphery of the process tube is configured by a pressure-resistant member, but it is very costly to configure the casing that surrounds the process tube by a pressure-resistant member. There's a problem.

  An object of the present invention is to provide a heat treatment apparatus that can realize prevention of expansion of damage in an emergency such as an earthquake or a fire at a low cost.

  The heat treatment apparatus according to the present invention is configured to perform heat treatment on a workpiece enclosed in a process tube. The heat treatment apparatus includes a heating unit, an airtight space forming unit, and a volume changing unit. The heating means is disposed around the process tube and is configured to heat the process tube.

The airtight space forming means is configured to form an airtight space that is airtightly surrounding at least the heating means and in which the oxygen concentration does not exceed a predetermined concentration . The hermetic space forming means is constituted by a partition having a property of keeping the hermeticity of the hermetic space so that the heater is not exposed to the outside air, for example.

  The volume changing unit is provided in the hermetic space forming unit and is configured to change the volume of the hermetic space according to the internal pressure of the hermetic space. Examples of the configuration of the volume changing means include a flexible partition wall configured to bend according to the internal pressure of the airtight space, and a tank communicating with the airtight space, and contracts or expands according to the internal pressure of the airtight space. However, it is not limited to these.

  In this configuration, even when the process tube is damaged and the internal pressure of the airtight space is suddenly changed, the airtight space forming means for defining the airtight space is not damaged. Airtightness around the process tube is maintained. As a result, since the heating means does not come into contact with oxygen from the outside, even if the combustible gas leaked from the process tube comes into contact with the heating means, no explosion or fire occurs.

  In consideration of lowering the oxygen concentration around the heating means as much as possible, the oxygen concentration detecting means for measuring the oxygen concentration in the airtight space and the oxygen concentration in the airtight space when the oxygen concentration in the airtight space exceeds a predetermined concentration. It is preferable to provide an inert gas introduction means configured to introduce an inert gas.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to implement | achieve prevention of the expansion of the damage in emergency, such as an earthquake or a fire, at low cost.

  The outline of the heat processing apparatus 100 which concerns on embodiment of this invention is demonstrated using FIG. The heat treatment apparatus 100 is configured to perform heat treatment on a semiconductor substrate or a glass substrate in a reduced pressure state, for example. Examples of the heat treatment include chemical vapor deposition, diffusion, and annealing.

  The heat treatment apparatus 100 includes at least a furnace body 10, a gas supply unit 50, a gas selection unit 60, a discharge unit 40, and a control unit (not shown) that comprehensively controls each component.

  The furnace body 10 includes at least a process tube 12 made of quartz glass, a floor plate 22 made of quartz glass, and a heater 14. The process tube 12 has an opening on its bottom surface and defines a processing chamber in which heat treatment is performed. The floor plate 22 is supported by an elevator device (not shown) so as to be movable up and down, and is configured to selectively seal the opening of the process tube 12. The heater 14 is disposed around the process tube 12 and is configured to heat the workpiece in the process tube 12.

The gas supply unit 50 includes first to fourth gas supply units (52, 54, 56, 58) that supply gases to be supplied to the process tube 12, respectively. In this embodiment, SiH ₄ (silane) is supplied from the first gas supply unit 52, Ar is supplied from the second gas supply unit 54, and N ₂ is supplied from the third gas supply unit 56. The type of gas supplied from the four gas supply units (52, 54, 56, 58) is not limited to this combination. Also, the number of gas supply units is not limited to four, and the number of gas supply units can be increased or decreased as appropriate.

  The gas selection unit 60 is configured to relay the gas supply unit 50 and the process tube 12. The gas selection unit 60 selectively selects the gas supplied from each of the first to fourth gas supply units (52, 54, 56, 58) based on the control signal supplied from the control unit. To introduce.

  The discharge unit 40 has an exhaust pipe provided with, for example, an air valve and a manual valve, and is configured to exhaust from the process tube 12. Further, the discharge unit 40 includes a decompression pump (for example, a vacuum pump) for decompressing the inside of the process tube.

  Next, the explosion-proof system 16 applied to the vertical heat treatment apparatus 100 will be described. The explosion-proof system 16 includes an airtight space forming part configured to form an airtight space that hermetically surrounds the upper portion of the process tube 12 and the heater 14. In this embodiment, the hermetic space forming part is constituted by the soft shell 161, the wall part 162, and the bottom part of the furnace body 10. The soft shell 161 serves as a partition wall that defines an airtight space, and is disposed at a predetermined position inside the furnace body 10 by being supported by a support member such as a frame member (not shown). The soft shell 161 is configured by a flexible member so as to bend according to the internal pressure of the airtight space. Examples of the configuration of the soft shell 161 include a configuration in which a glass cloth is covered with an aluminum foil and bonded with a resin or the like, such as an aluminum glass cloth, and a commercially available one can be used. However, the soft shell 161 only needs to have a heat resistance function, a function of maintaining airtightness, and a function of absorbing a pressure difference between inside and outside, and is not limited to the above-described materials. In this embodiment, the soft shell 161 corresponds to the volume changing means of the present invention.

The wall 162 is erected on the bottom of the furnace body 10 and is configured to support the pressure gauge 30, the thermometer 28, and the cooling device 24. The pressure gauge 30 measures the pressure in the airtight space. The thermometer 28 measures the temperature in the airtight space. The cooling device 24 includes a fan, a radiator, and the like, and is configured to suck the gas in the airtight space, cool it, and return it to the airtight space. The cooling device 24 is connected to an atmosphere introduction valve 26 configured to selectively introduce the atmosphere. The wall 162 is provided with a maintenance door 164 as shown in FIG. The door 164 is sealed by a sealing member. The door 164 is an optional component in the present invention, and is not necessarily required when implementing the present invention.

  The explosion-proof system 16 further selects an oxygen concentration meter 18 that measures the oxygen concentration in the airtight space, an inert gas supply unit 20 configured to introduce an inert gas into the airtight space, and a gas in the airtight space. A check valve 32 is provided for exhausting automatically. In this embodiment, nitrogen is supplied from the inert gas supply unit 20 to the airtight space. The inert gas supply unit 20 is controlled to introduce nitrogen into the airtight space when the oxygen concentration in the airtight space exceeds a predetermined concentration (for example, 5% or more). The nitrogen introduced into the airtight space is sucked from the suction port 23 by the blower 25 and introduced into the heater from the blowout nozzle 27.

  In the above configuration, when the process tube 12 is damaged due to an earthquake or the like, the pressure in the airtight space is suddenly reduced due to the reduced pressure atmosphere of the process tube 12, but this decrease in internal pressure is absorbed by the soft shell 161. Specifically, the volume of the airtight space is reduced by bending the soft shell 161 inward. As described above, the soft shell 161 absorbs the decrease in the internal pressure of the airtight space, so that the process tube 12 and the heater 14 can be kept airtight even after the process tube 12 is damaged. For this reason, since the process tube 12 is damaged, the combustible gas does not leak to the outside, and oxygen from the outside does not touch the heater 14. For this reason, since the heater 14 does not come into contact with oxygen from outside the airtight space, no explosion or fire occurs even when the heater 14 comes into contact with the combustible gas leaked from the process tube 12. .

  Furthermore, by using the soft shell 161, it is possible to reduce the cost as compared with the case where the entire periphery of the process tube 12 and the heater 14 is surrounded by a pressure-resistant member.

  Next, another embodiment of the present invention will be described with reference to FIG. The basic configuration of the heat treatment apparatus 200 according to this embodiment is the same as that of the heat treatment apparatus 100 according to the previous embodiment. However, in the heat treatment apparatus 200, a hard shell 166 is used instead of the soft shell 161. When the airtight space is defined by the hard shell 166, as shown in FIG. 3, the flexible tank 42 is preferably communicated with the confidential space. In such a configuration, since the tank 42 contracts or expands according to the internal pressure of the airtight space, it is possible to prevent the hard shell 166 from being damaged due to the damage of the process tube 12 without using a pressure-resistant member for the hard shell 166. .

  Further, as in the heat treatment apparatus 300 of FIG. 4, it is possible to use both the soft shell 161 and the flexible tank 42 in combination.

  According to the configuration according to the above embodiment, even when a flammable gas such as hydrogen and a dangerous gas such as silane are used in the heat treatment process, it is possible to prevent an explosion from occurring due to breakage of the process tube 12. .

  In the above-described embodiment, the example in which the heat treatment is performed with the inside of the process tube in a reduced pressure state has been described. However, the present invention can also be applied to the case where the heat treatment is performed with the process tube 12 in a normal pressure state.

  The above description of the embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

It is a figure which shows the outline of the heat processing apparatus which concerns on embodiment of this invention. It is a figure which shows the outline of the heat processing apparatus which concerns on embodiment of this invention. It is a figure which shows the other example of the heat processing apparatus which concerns on embodiment of this invention. It is a figure which shows the other example of the heat processing apparatus which concerns on embodiment of this invention.

Explanation of symbols

10-furnace body 12-process tube 14-heater 16-explosion-proof system 18-oxygen concentration meter 20-inert gas supply part 161-soft shell 162-wall part

Claims (4)

A heat treatment apparatus for performing heat treatment on a workpiece enclosed in a process tube,
Heating means disposed around the process tube and configured to heat the process tube;
An airtight space forming means configured to form an airtight space in an airtight space surrounding at least the heating means and having an oxygen concentration not exceeding a predetermined concentration ;
Volume changing means provided in the airtight space forming means and configured to change the volume of the airtight space according to the internal pressure of the airtight space;
The heat processing apparatus provided with. 2. The heat treatment apparatus according to claim 1, wherein the volume changing unit includes a partition wall that defines the airtight space and has a flexible partition wall configured to bend according to an internal pressure of the airtight space. The heat treatment apparatus according to claim 1, wherein the volume changing unit includes a tank that communicates with the airtight space and is configured to contract or expand in accordance with an internal pressure of the airtight space. Oxygen concentration detection means for measuring the oxygen concentration in the airtight space;
An inert gas introduction means configured to introduce an inert gas into the airtight space when the oxygen concentration in the airtight space exceeds a predetermined concentration;
The heat treatment apparatus according to any one of claims 1 to 3 , further comprising:

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