JP2015076480A - Purge device and purge method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress temperature rise of a purge gas within an allowable range.SOLUTION: A flow rate of a purge gas flowing in a pipeline is controlled by a flow controller and heat from the flow controller is radiated by a heat radiation member to suppress temperature rise of the purge gas.

Description

  The present invention relates to a purge apparatus and a purge method used in a stocker, a load port, a semiconductor processing apparatus, and the like.

  It is known to store a semiconductor wafer while purging it with a purge gas such as nitrogen gas or clean dry air (Patent Document 1 JP 2013-133194 A). Patent Document 1 describes that a flow rate control device such as a mass flow controller is provided for each front opening for supplying purge gas in order to keep the flow rate of purge gas constant.

  Related prior art is shown. In the mass flow controller, a part of gas is branched from the main channel to the sensor channel, and the flow rate is measured in the sensor channel. Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2009-300403) discloses that a heat radiator is provided at a branch portion between the main channel and the sensor channel.

JP2013-133194 JP2009-300403

  The inventor has found that the purge gas is heated by going through the mass flow controller. When the temperature of the purge gas increases, the temperature of the semiconductor wafer in the container also increases, which may affect the properties of the manufactured semiconductor. For this reason, it is necessary to suppress the temperature rise of the purge gas within an allowable range by a flow rate control device such as a mass flow controller.

  An object of the present invention is to reduce the influence on the purge target article by suppressing the temperature rise of the purge gas within an allowable range.

The present invention relates to a purge device for supplying a purge gas from a pipe.
A flow rate control device for controlling the flow rate of the purge gas flowing through the piping;
And a heat dissipating member that dissipates heat generated by the flow control device.

The present invention also provides a purge method for supplying a purge gas from a pipe.
While controlling the flow rate of the purge gas flowing through the piping by the flow rate control device,
The heat from the flow control device is dissipated by the heat dissipating member, and the temperature rise of the purge gas is suppressed.

  The flow rate control device is, for example, a mass flow controller, but may be any type as long as it can control the flow rate of the purge gas. The heat radiating member is preferably a heat conductive putty, a heat conductive adhesive, a heat pipe or the like in addition to the heat conductive sheet of the embodiment, and the metal frame itself to which the flow control device is attached is not regarded as a heat radiating member. Even if the flow control device is fixed to the metal frame, it is difficult to bring them into close contact with each other, leaving a gap. This gap acts as a heat insulating layer and prevents heat dissipation from the flow control device. On the other hand, when the flow control device is cooled by the heat radiating member, the temperature rise of the purge gas can be limited within an allowable range. In this specification, the description regarding the purge device is also applied to the purge method as it is.

  Preferably, the heat dissipating member is composed of a heat conductive sheet disposed between the back surface of the flow rate control device and the metal frame and in close contact with both the back surface and the metal frame. The heat conduction sheet is a sheet in which heat conductive particles such as carbon and metal powder are mixed with plastic such as silicon and acrylic, and is placed between the back of the flow control device and the metal frame, and is in close contact with both. . Since the heat conductive sheet has a much higher thermal conductivity than air, the heat insulation effect due to the air remaining between the flow control device and the metal frame is eliminated, and heat dissipation from the flow control device to the metal frame is promoted.

  More preferably, the metal frame is a frame for mounting the flow rate control device, and the flow rate control device is directly fixed to the metal frame via the heat conductive sheet without using an intermediate metal frame (mounting bracket) or the like. Therefore, heat can be efficiently radiated from the flow control device. Such an example is shown in FIGS.

  The use of the purge device is arbitrary, such as a load port, a semiconductor processing device, etc., and the purge target is also arbitrary, such as pharmaceuticals and reticles. However, preferably, the purge device is provided in a stocker of a container that accommodates a semiconductor wafer, and is configured to supply a purge gas from a pipe into the container. Work-in-process semiconductor wafers stored in stockers at semiconductor factories are sensitive to temperature and are also affected by slight temperature increases by the flow control device. Therefore, if the temperature of the purge gas in the stocker is prevented from increasing, variations in the characteristics of the manufactured semiconductor can be reduced.

Block diagram of purge device of embodiment The figure which shows the structure of the mass flow controller used in the Example Front view showing installation of mass flow controller in the embodiment Side view showing installation of mass flow controller in the embodiment Side view of main part of stocker in the embodiment Side view showing mass flow controller installation in a variation Side view showing attachment of mass flow controller in second modified example Side view showing attachment of mass flow controller in third modification

  In the following, an optimum embodiment for carrying out the present invention will be shown. The scope of the present invention should be determined according to the understanding of those skilled in the art based on the description of the scope of the claims, taking into account the description of the specification and well-known techniques in this field.

  FIGS. 1-8 shows the purge apparatus 1 of an Example and its deformation | transformation. In FIG. 1, reference numeral 2 denotes a mass flow controller, which is an example of a flow rate control device, to which a heat radiating member 9 is attached. A purge gas such as nitrogen gas or clean dry air is sent from the pipe 3, passes through the manual valve 4, stabilizes the downstream pressure by the regulator 5, and is sent to the pipe 7 via the control valve 6. The mass flow controller 2 is provided for each front end of the semiconductor wafer stocker in the clean room, and introduces a purge gas from the nozzle 8 to a container such as FOUP that accommodates the semiconductor wafer. The container for storing semiconductor wafers in the stocker is not limited to FOUP, but is not limited to a portable container, and may be a fixed container.

  FIG. 2 shows the structure of the mass flow controller 2. Reference numeral 10 denotes a case of plastic, metal, etc., 11 denotes a gas inlet, and 12 denotes a gas outlet. The purge gas entered from the gas inlet 11 is branched at a constant rate, and the flow rate of the purge gas branched by the flow rate sensor 13 is measured. Based on this measured value, the flow rate is controlled by the control valve 14 and exhausted from the gas outlet 12. The branched purge gas is joined before the gas outlet 12. Reference numeral 15 denotes a substrate, which is equipped with a control circuit and the like, communicates with the outside from the terminal 16, and receives power supply. Reference numerals 17 and 18 denote pipes on the inlet side and the outlet side, which are part of the pipe 7. Although the flow rate sensor 13 generates a slight amount of heat, the amount of heat generated is small, and the influence of the purge gas on the temperature rise can be ignored.

  Most of the heat generated by the mass flow controller 2 is due to the substrate 15 and the control valve 14. Depending on the flow rate at that time, if no countermeasure is taken, the mass flow controller 2 raises the purge gas by about 1 to 2 ° C., for example. May be warm. Even a temperature increase of this level may cause a variation in semiconductor manufacturing quality.

  3 and 4 show the attachment of the mass flow controller 2 using the heat conductive sheets 25 and 26 as heat dissipation members. 20 is a metal frame made of, for example, aluminum and plays a role of attaching the mass flow controller 2 to the metal plate 30 of the shelf of the stocker. The metal frame 20 is preferably provided with fins 21 for heat dissipation. Since stainless steel, which is a normal material for clean rooms, has low thermal conductivity, it is preferable that the metal frame 20 be made of aluminum that has high thermal conductivity and is allowed to be used in a clean room. The upper part of the metal frame 20 is bent into a flange 22, and the mass flow controller 2 is fixed with a screw 28 or the like. A heat conductive sheet 26 is arranged between the metal frame 20 and the back surface of the mass flow controller 2 so that no gap remains between them. Similarly, a gap remains between the flange 22 and the upper surface of the mass flow controller 2. The heat conductive sheet 25 is disposed so as not to be present. The metal frame 20 is fixed to the metal plate 30 with a nut 29 or the like. Preferably, the metal plate 30 is made of aluminum instead of stainless steel.

  The heat conductive sheets 25 and 26 are sheets in which a heat conductive material such as carbon or metal powder is mixed with plastic such as acrylic or silicon, and the thickness is about 0.01 mm to 3 mm. The heat conductive sheets 25 and 26 are non-adhesive sheets, and the mass flow controller 2 is fixed with screws 28. However, for example, when a heat conductive sheet having adhesive on both sides is used, the screw 28 is unnecessary. The heat conductive sheets 25 and 26 bring the mass flow controller 2 into close contact with the metal frame 20 and the flange 22 without any gaps such as air, and promote heat dissipation from the mass flow controller 2 to the metal frame 20. A putty, an adhesive, a heat pipe, or the like in which a heat conductive material is mixed in plastic may be used. However, the heat conductive sheets 25 and 26 are preferable because they are easy to construct and have less unnecessary outgas.

  FIG. 5 shows a state in which the metal frame 20 of FIGS. 3 and 4 is attached to the metal plate 30. The metal plate 30 is, for example, a plate on the back side of the shelf of the stocker, and the elements of the purge device such as the mass flow controller 2 and a valve for each frontage not shown are fixed. Reference numeral 38 denotes a support, to which a shelf receiver 32 is attached. A space on the shelf receiver 32 is a frontage. An article 34 such as FOUP is positioned and placed by a coupling pin 36, and purge gas is supplied from the nozzle 8 into the article 34. Is done.

  As indicated by a chain line in FIG. 5, the mass flow controller 2 may be attached to the outer plate 40 of the stocker. Reference numeral 42 denotes a gap between the metal plate 30 and the outer plate 40. When a clean air downflow is provided in the gap 42, the mass flow controller 2 can be cooled more efficiently. Reference numeral 44 denotes a double-sided adhesive heat conductive sheet for attaching the mass flow controller 2, but a non-adhesive heat conductive sheet may be used using the metal frame 20 and screws 28 as shown in FIGS. 3 and 4. . The outer plate 40 to which the mass flow controller 2 is attached is preferably made of aluminum, not stainless steel.

  FIG. 6 shows attachment of the mass flow controller 2 in a modified example. The mass flow controller 2 is screwed to the mounting bracket 50 made of aluminum via the heat conductive sheets 25 and 26, and the mounting bracket 50 is fixed to the metal frame 54 made of aluminum via the heat conductive sheet 52 with screws 51 or the like. Install. In the modified example of FIG. 6, the heat radiation from the mass flow controller 2 is less than that of the embodiment of FIGS.

  FIG. 7 shows a second modification in which the mass flow controller 2 is attached to the metal plate 30 or the outer plate 40 via the double-sided adhesive heat conductive sheet 44 without the metal frame 20 or the like. In this case, the metal plate 30 or the outer plate 40 is preferably made of aluminum.

  FIG. 8 shows a third modified example in which a flow dividing plate 70 is provided on the upper portion of the metal plate 30 to guide the downflow of clean air to the gap 42 between the metal plate 30 and the outer plate 40. The mass flow controller 2, the metal plate 30, the outer plate 40, etc. are cooled by this air flow. The mass flow controller 2 may be attached to the metal plate 30 or the outer plate 40, and the side on which the mass flow controller 2 is attached is preferably made of aluminum. Reference numeral 72 denotes a shelf composed of a plurality of openings. For example, a pair of shelves 72 are provided, and a space 74 between them is used as a travel space 74 of a transport device such as a stacker crane. In FIG. 8, only one shelf 72 is shown.

The embodiment has the following characteristics.
1) The temperature of the purge gas by the mass flow controller 2 can be raised to, for example, less than 1 ° C., particularly less than 0.5 ° C.
2) Compared with the existing attachment method of the mass flow controller 2, it is only necessary to add the heat conductive sheets 25 and 26, so that the construction is easy.
3) By making the metal frame 20, the metal plate 30, the outer plate 40, etc. made of aluminum, heat dissipation becomes easier.
4) Even if the fins 21 are provided on the metal frame 20, heat dissipation becomes easier.

  If a cooling device is provided on the side of the pipe 3 through which purge gas is introduced from the outside, the structure of the stocker 76 is increased in size. Therefore, it is easier to radiate the mass flow controller 2 using the heat conductive sheets 25 and 26 as in the embodiment.

DESCRIPTION OF SYMBOLS 1 Purge apparatus 2 Mass flow controller 3, 7 Piping 4 Manual valve 5 Regulator 6 Control valve 8 Nozzle 9 Heat radiating member 10 Case 11 Gas inlet 12 Gas outlet 13 Flow sensor 14 Control valve 15 Board | substrate 16 Terminal 17, 18 Piping 20 Metal frame 21 Fin 22 庇 25, 26 Heat conduction sheet 28 Screw 29 Nut 30 Metal plate 32 Shelf bracket 34 Article 36 Coupling pin 38 Post 40 Outer plate 42 Gap 44 Heat conduction sheet 50 Mounting bracket 51 Screw 52 Heat conduction sheet 54 Metal frame 70 Current distribution plate 72 Shelf 74 Traveling space 76 Stocker

Claims (5)

In a purge device for supplying purge gas from piping,
A flow rate control device for controlling the flow rate of the purge gas flowing through the piping;
And a heat radiating member for radiating heat generated by the flow rate control device.   The heat dissipating member comprises a heat conductive sheet disposed between the back surface of the flow rate control device and the metal frame so as to be in close contact with both the back surface and the metal frame. 1 purge device.   The purge apparatus according to claim 2, wherein the metal frame is a frame for mounting the flow control device.   The purge according to any one of claims 1 to 3, wherein the purge device is provided in a stocker of a container that accommodates a semiconductor wafer, and is configured to supply a purge gas from the pipe into the container. apparatus. In the purge method of supplying purge gas from piping,
The flow rate of the purge gas flowing through the pipe is controlled by a flow rate control device,
A purge method, wherein heat from the flow rate control device is radiated by a heat radiating member to suppress the temperature rise of the purge gas.

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