JP2007035754A - Substrate treatment equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep an airtight chamber of a lifting table installed in a standby chamber in the airtight seal state. <P>SOLUTION: Batch type heat treatment equipment 10 comprises a treatment chamber 19 for treating a group of wafers 1 held by a boat 13, the standby chamber 12 wherein the boat 13 stands by immediately below the treatment chamber 19, boat elevator 24 which is installed outside the standby chamber 12 to carry in and out the boat 13 from the treatment chamber 19, the lifting table 37 which is installed inside the standby chamber 12 and supports the boat 13, and up-and-down shaft 32 which is inserted into the standby chamber 12 to connect the lifting table 37 and the boat elevator 24. A tube 54 connected to a helium gas supply line 55 is inserted into the airtight chamber 37d of the lifting table 37 from the up-and-down shaft 32, and a helium gas detector 58 is installed in an exhaust pipe 57 for exhausting a gas out of the standby chamber 12. By detecting a helium gas circulating in the exhaust pipe when it is supplied to the airtight chamber of the lifting table by means of the helium gas detector, the airtight chamber of the lifting table is checked for leakage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate processing apparatus, and more particularly to a hermetic maintenance technique for a hermetic chamber. For example, diffusion, CVD, epitaxial growth, or the like is performed on a semiconductor wafer (hereinafter referred to as a wafer) on which a semiconductor integrated circuit including semiconductor elements is formed. The present invention relates to an effective heat treatment apparatus (furnace) for performing a thermal treatment.

  As a heat treatment apparatus for performing heat treatment on wafers, a process tube in which a treatment chamber for heat treatment is formed in a state where a plurality of wafers are held in a boat, and a boat that is formed directly below the process tube and is carried into and out of the treatment chamber. 2. Description of the Related Art A batch type vertical hot wall heat treatment apparatus including a standby chamber for waiting and a boat elevator that lifts and lowers a boat and carries it in and out of the processing chamber is widely used.

In the conventional batch type vertical hot wall type heat treatment apparatus, the boat elevator is constituted by a feed screw shaft device and is installed vertically in the standby chamber, and the lower end of the feed screw shaft is supported in the standby chamber and the standby chamber at the upper end. The motor is driven to rotate by a motor installed outside. For example, see Patent Document 1.
However, in such a conventional batch type vertical hot wall heat treatment apparatus, since the boat elevator is installed inside the waiting room, the grease and wiring cables used in the feed screw shaft apparatus and the guide rail are used. There is a problem in that the scattering of the organic substance causes contamination of the wafer.
When the boat heated to a high temperature is lowered into the standby chamber and the temperature of the standby chamber rises, the amount of evaporation of the organic material increases.
For this reason, after the heat treatment in the processing chamber is completed, the boat or wafer group is cooled to a temperature of, for example, 100 ° C. or less while the board is left in the processing chamber, and the boat or wafer group temperature is sufficiently lowered, The boat is carried out from the processing chamber.
However, if the boat is unloaded from the processing chamber after the temperature of the boat or wafer group has been sufficiently lowered, the throughput of the batch type vertical hot wall heat treatment apparatus is lowered.

  Therefore, while installing the boat elevator outside the waiting room and connecting the elevator body of the boat elevator and the boat with the lifting shaft, the batch type vertical hot water configured to prevent the scattering of organic substances from the boat elevator. A wall-type heat treatment apparatus has been proposed. For example, see Patent Document 2.

JP-A-9-298137 JP 2003-297760 A

However, in the batch type vertical hot wall type heat treatment apparatus in which the boat elevator is installed outside the waiting room and the elevator body of the boat elevator and the elevator platform for raising and lowering the boat are connected by the elevator shaft, the following problems occur: It was clarified by the present inventors that there is a point.
1) In order to secure electrical wiring and cooling water channels to the boat rotation drive device, it is necessary to form the lifting platform and lifting shaft of the boat elevator in a hollow structure, but the airtightness of the hollow structure of the lifting platform and lifting shaft When the seal is insufficient, the inside of the hollow portion of the lifting platform and the lifting shaft communicates with the outside of the standby chamber, so that outside air enters the standby chamber.
2) Generally, measures to ensure a hermetic seal of a hermetic chamber such as a standby chamber include connecting a helium (He) leak detector to the exhaust line of the hermetic chamber and pushing helium gas against the outer wall of the hermetic chamber. There is a method of identifying the leak location.
However, since the lifting platform that is an airtight body is installed inside the standby chamber that is the hermetic chamber, helium gas cannot be blown onto the lifting platform. As a result, it is not possible to ensure an airtight seal of the lifting platform that is an airtight body.

  The objective of this invention is providing the substrate processing apparatus which can ensure the airtight seal | sticker of the airtight body installed in the airtight chamber.

Typical means for solving the above-described problems are as follows.
(1) a processing chamber for providing a space for processing a substrate;
An airtight chamber hermetically connected to the processing chamber;
An exhaust system for exhausting the atmosphere in the hermetic chamber;
A hollow airtight body provided so that most of the airtight chamber is located, wherein the hollow portion is isolated from the atmosphere of the airtight chamber;
A supply line for supplying a gas for leak check into the hermetic body;
A substrate processing apparatus comprising:
(2) The substrate processing apparatus according to (1), further including a sensor that detects the presence of the leak check gas in the hermetic chamber or the exhaust system.

  According to the above means, the leak check gas is supplied to the inside of the hermetic body through the gas supply line, and the presence of the leak check gas in the hermetic chamber or the exhaust system is detected by the sensor, so that the hermetic seal of the hermetic body is detected. Therefore, the airtight seal of the airtight body can be secured.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the present embodiment, a substrate processing apparatus according to the present invention is a batch type vertical hot wall type heat treatment furnace (hereinafter referred to as a batch type heat treatment apparatus) which is a processing unit for performing heat treatment on a wafer in a method for manufacturing a semiconductor device. ).
As shown in FIG. 1, the batch-type heat treatment apparatus 10 includes a housing 11, and a standby chamber 12 in which the boat 13 waits is formed in the housing 11 so that the boat 13 can be accommodated. ing. The standby chamber 12 is constructed as an airtight chamber having an airtight performance capable of maintaining a pressure below atmospheric pressure. That is, the standby chamber 12 constitutes an airtight chamber that is airtightly connected to the processing chamber.
A wafer loading / unloading port 14 is opened on the front wall of the housing 11, and the wafer loading / unloading port 14 is opened and closed by a gate 15.
A boat loading / unloading port 16 is opened on the ceiling wall of the housing 11, and the boat loading / unloading port 16 is opened and closed by a shutter 17.
A heater unit 18 is vertically installed on the casing 11, and a process tube 20 forming a processing chamber 19 is disposed inside the heater unit 18. The process tube 20 is formed in a cylindrical shape with the upper end closed and the lower end opened, and is disposed concentrically with the heater unit 18. The cylindrical hollow portion of the process tube 20 constitutes a processing chamber 19 that provides a space for processing a wafer.
Connected to the lower end of the process tube 20 are a gas introduction pipe 21 for introducing a raw material gas, a purge gas or the like into the processing chamber 19 of the process tube 20 and an exhaust pipe 22 for exhausting the inside of the process tube 20. ing.

An installation table 23 is installed outside the standby chamber 12 of the housing 11, and a boat elevator 24 for moving the boat up and down is installed on the installation table 23.
The boat elevator 24 is provided with a guide rail 27 and a feed screw shaft 28 laid vertically by an upper mounting plate 25 and a lower mounting plate 26, respectively, and an elevating body 29 is fitted on the guide rail 27 so as to be vertically movable. Are combined. The elevating body 29 is screwed to the feed screw shaft 28 so as to advance and retract in the vertical direction. The upper end portion of the feed screw shaft 28 passes through the upper mounting plate 25 and is connected to a motor 30 installed on the upper mounting plate 25. That is, the feed screw shaft 28 is configured to be driven to rotate forward and backward by the motor 30.
In order to improve the operation and backlash, a ball screw mechanism is used at the threaded portion between the feed screw shaft 28 and the elevating body 29.

An arm 31 protrudes horizontally on the side surface of the lifting body 29, and a lifting shaft 32 formed in a cylindrical shape is fixed to the tip of the arm 31 downward in the vertical direction.
An inner cylinder 34 is concentrically arranged and fixed in the hollow portion 33 of the elevating shaft 32. The inner cylinder 34 is formed in a cylindrical shape having an outer diameter smaller than the inner diameter of the elevating shaft 32.
The elevating shaft 32 is inserted through the insertion hole 35 formed in the ceiling wall of the housing 11 and the lower end portion is inserted into the standby chamber 12, and between the upper surface of the ceiling wall of the housing 11 and the lower surface of the arm 31. Is provided with a bellows 36 for hermetically sealing the insertion hole 35.
A hollow airtight body provided at the lower end of the standby chamber 12 of the elevating shaft 32 so that most of the standby chamber 12 is located in the standby chamber 12. The hollow portion is isolated from the atmosphere of the standby chamber 12. The elevator table 37 is horizontally arranged and fixed, and the elevator table 37 is configured to raise and lower the boat 13.
The lifting platform 37 includes a main body 37a formed in a box shape having an upper surface opened, and a lid body 37b formed in the same flat plate shape as the main body 37a. The lid body 37b is sealed on the main body 37a. An airtight chamber 37d is formed by being put across 37c.

A bearing device 39 sealed by a magnetic fluid sealing device 38 is installed on the lower surface of the lid body 37b, which is the ceiling surface of the airtight chamber 37d of the lifting platform 37. The bearing device 39 rotatably supports a rotating shaft 40 inserted through the lid body 37b in the vertical direction, and the rotating shaft 40 is rotationally driven by a boat rotation driving motor 41.
The boat 13 is installed at the upper end of the rotating shaft 40 so as to stand vertically. The boat 13 is formed by a boat elevator 24 with respect to the processing chamber 19 of the process tube 20 in a state where a plurality of (for example, 25, 50, 75, 100) wafers 1 are horizontally supported with their centers aligned. It is configured to carry in and out as the elevator 37 is raised and lowered.
A seal cap 43 is installed on the upper surface of the lifting platform 37 via a seal ring 42. The seal cap 43 is configured to seal the boat loading / unloading port 16 of the housing 11 that becomes the furnace port of the processing chamber 19.

A cooling device 44 for cooling the magnetic fluid sealing device 38, the bearing device 39, and the boat rotation driving motor 41 is installed outside the magnetic fluid sealing device 38. A cooling water supply pipe 45 is provided in the cooling device 44. It is connected.
The cooling water supply pipe 45 is drawn out of the standby chamber 12 from the airtight chamber 37d through the hollow portion of the inner cylinder 34, and is connected to the cooling water supply source 47 via the variable flow rate control valve 46. .
A water passage 49 through which the cooling water 48 circulates is opened inside the seal cap 43, and the cooling water of the cooling device 44 is introduced into the water passage 49 by the introduction side connecting pipe 50. One end of the outlet side connecting pipe 51 is connected to the water passage 49, and the other end of the outlet side connecting pipe 51 is connected to the lower end of the hollow portion 33 of the elevating shaft 32.
A cooling water discharge pipe 52 is connected to the upper end of the hollow portion 33 of the elevating shaft 32, and the cooling water discharge pipe 52 is connected to a cooling water supply source 47. Accordingly, the cooling water 48 is introduced into the hollow portion 33 of the elevating shaft 32 by being introduced from the outlet-side connecting pipe 51 at the lower end and discharged from the cooling water discharge pipe 52 at the upper end.
Further, the power supply electric wire 53 of the boat rotation driving motor 41 is inserted into the hollow portion of the inner cylinder 34 and drawn out to the outside.

A tube 54 is inserted through the hollow portion of the inner cylinder 34 into the hermetic chamber 37 d of the lifting platform 37. One end of a leak check gas supply line (hereinafter referred to as supply line) 55 is connected to the outer end of the inner tube 34 of the tube 54, and the other end of the supply line 55 receives helium gas as a leak check gas. It is connected to a helium gas supply device 56 to be supplied. That is, the tube 54 constitutes a part of a leak check gas supply line for supplying a leak check gas into the hermetic chamber 37d.
On the other hand, an exhaust system exhaust pipe 57 that exhausts the atmosphere in the standby room 12 is connected to the standby room 12, and a helium gas detector 58 as a sensor that detects the presence of a leak check gas is connected to the exhaust pipe 57. is set up.
Incidentally, the helium gas detector 58 does not need to be always connected to the exhaust pipe 57, and may actually be connected and used during maintenance of the batch heat treatment apparatus 10. The same applies to the helium gas supply device 56.
The standby chamber 12 is connected to a nitrogen gas supply pipe 59 for supplying nitrogen gas as a purge gas to the standby chamber 12.

  Hereinafter, a film forming process using the batch heat treatment apparatus according to the above configuration will be described.

The wafer 1 to be formed is loaded into the waiting chamber 12 through the wafer loading / unloading port 14 of the housing 11 by a wafer transfer device (not shown) and loaded (charged) into the boat 13.
At this time, as shown in FIG. 1, the boat loading / unloading port 16 is closed by the shutter 17, thereby preventing the high temperature atmosphere of the processing chamber 19 from flowing into the standby chamber 12. For this reason, the wafer 1 being loaded and the loaded wafer 1 are not exposed to a high temperature atmosphere, and the occurrence of adverse effects such as natural oxidation due to the wafer 1 being exposed to a high temperature atmosphere is prevented.

  When a predetermined number of wafers 1 are loaded into the boat 13, the wafer loading / unloading port 14 is closed by the gate 15 and the boat loading / unloading port 16 is opened by the shutter 17, as shown in FIG. 2. .

Subsequently, the seal cap 43 and the boat 13 supported by the lifting platform 37 are lifted by the motor 30 of the boat elevator 24 via the lifting body 29 and the lifting shaft 32, and the boat loading / unloading exit into the processing chamber 19 of the process tube 20. 16 is loaded (boat loading).
As shown in FIG. 2, when the boat 13 reaches the upper limit, the periphery of the upper surface of the seal cap 43 closes the boat loading / unloading port 16 in a sealed state, so that the processing chamber 19 of the process tube 20 is airtight. Closed state.
Incidentally, when the boat 13 is carried into the processing chamber 19 and the elevating shaft 32 is raised, the bellows 36 extends upward.

Thereafter, the process chamber 19 of the process tube 20 is closed in an airtight manner, is exhausted by the exhaust pipe 22 so as to have a predetermined pressure, heated to a predetermined temperature by the heater unit 18, and a predetermined source gas is introduced into the gas. The pipe 21 supplies a predetermined flow rate.
Further, the boat 13 is rotated by a boat rotation drive motor 41.
As a result, a desired CVD film corresponding to preset processing conditions is formed on the wafer 1.
At this time, since the boat 13 is rotated by the boat rotation driving motor 41, the source gas is uniformly brought into contact with the surface of the wafer 1, so that the CVD film is uniformly formed on the wafer 1.

Here, the cooling water 48 is circulated through the cooling device 44 and the water passage 49 of the seal cap 43 through the cooling water supply pipe 45 and the cooling water discharge pipe 52, so that the seal ring 42 and the magnetic fluid of the seal cap 43 are heated. Deterioration of the sealing device 38 and the bearing device 39 is prevented.
At this time, since the cooling water 48 flows through the hollow portion 33 of the lifting shaft 32, the lifting shaft 32 and the inner cylinder 34 are also cooled.

When the processing time set in advance elapses, as shown in FIG. 1, the lifting platform 37 that supports the boat 13 and the seal cap 43 is moved by the motor 30 of the boat elevator 24 via the lifting shaft 32 and the lifting body 29. By being lowered, the boat 13 holding the processed wafer 1 is carried out (boat unloading) to the standby chamber 12.
At this time, the bellows 36 is shortened downward as the elevating shaft 32 is lowered.

When the boat 13 is unloaded from the processing chamber 19 to the standby chamber 12, the boat loading / unloading port 16 is closed by the shutter 17.
Next, the wafer loading / unloading port 14 in the standby chamber 12 is opened by the gate 15, and the processed wafer 1 in the boat 13 is removed (discharged) by the wafer transfer device.
At this time, since the thermal expansion of the elevating shaft 32 is prevented, the reference height of the boat 13 is prevented from deviating, and therefore, the removal work of the processed wafer 1 from the boat 13 by the wafer transfer device is not performed. It will be executed properly and quickly.

  Thereafter, by repeating the above-described operation, the wafer 1 is batch-processed by the batch heat treatment apparatus 10, for example, 25 sheets, 50 sheets, 75 sheets, and 100 sheets each.

By the way, the lifting platform 37 is installed in the standby chamber 12, and the airtight chamber 37 d of the lifting platform 37 is in communication with the outside air through the hollow portion of the inner cylinder 34 laid on the lifting shaft 32. For this reason, if the hermetic seal of the airtight chamber 37d by the seal ring 37c of the lifting / lowering table 37 is insufficient, the outside air enters the standby chamber 12 through the hollow portion of the inner cylinder 34 and the airtight chamber 37d of the lifting / lowering table 37.
In order to prevent the outside air from entering the standby chamber 12, it is necessary to monitor the hermetic seal state of the hermetic chamber 37d by the seal ring 37c of the lifting platform 37 and maintain it at a certain level or higher.
Therefore, in the batch heat treatment apparatus 10 according to the present embodiment, the hermetic seal state of the hermetic chamber 37d of the lifting platform 37 can be easily and quickly recognized.
Next, a method for authorizing the hermetic seal state of the hermetic chamber 37d of the lifting platform 37 in the batch heat treatment apparatus 10 according to the present embodiment will be described.

For example, during regular or irregular maintenance work of the batch heat treatment apparatus 10, helium gas as a leak check gas is supplied from the helium gas supply device 56 through the supply line 55 and the tube 54 to the airtight chamber 37 d of the lifting platform 37. At the same time, the presence of helium gas exhausted from the standby chamber 12 is detected by a helium gas detector 58 installed in the exhaust pipe 57 that exhausts the standby chamber 12.
For example, when the sealing performance in the seal ring 37c of the hermetic chamber 37d of the lifting platform 37 is degraded, the helium gas supplied to the hermetic chamber 37d enters the standby chamber 12 from the place where the sealing performance of the seal ring 37c is degraded. Leak. Since the helium gas leaked into the standby chamber 12 is exhausted by the exhaust pipe 57, the helium gas detector 58 detects the helium gas.
Therefore, when the helium gas is detected by the helium gas detector 58, it can be recognized that the hermetic seal state in the hermetic chamber 37d of the lifting platform 37 is lowered. On the other hand, when helium gas is not detected by the helium gas detector 58, it can be determined that the hermetic seal state in the hermetic chamber 37d of the lifting platform 37 is normal.
For example, when the concentration of the helium gas detected by the helium gas detector 58 is equal to or higher than a preset concentration, the seal ring 37c that hermetically seals the hermetic chamber 37d of the lifting platform 37 is replaced.

  According to the embodiment, the following effects can be obtained.

1) A helium gas supply line is connected to the airtight chamber of the lifting platform, and a helium gas detector is installed in the exhaust pipe that exhausts the standby chamber, thereby supplying helium gas into the airtight chamber of the lifting platform through the helium gas supply line. At the same time, since the helium gas flowing through the exhaust pipe can be detected by the helium gas detector, the hermetic seal state of the hermetic chamber of the lifting platform can be recognized.

2) By accrediting the hermetic seal state of the hermetic chamber of the lifting platform, the hermetic seal state of the hermetic chamber of the lifting platform is always above a certain level by replacing the seal ring that hermetically seals the hermetic chamber of the lifting platform. Since it can be maintained, contamination of the wafer by particles and organic matter caused by outside air entering the standby chamber can be prevented.

3) By using helium gas as the leak check gas, it is possible to prevent contamination of the wafer by the leak check gas, so production of batch-type heat treatment equipment by monitoring the airtight state of the airtight chamber of the elevator platform The fall of property can be prevented.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  For example, the helium gas detector is not limited to being installed in the exhaust pipe that exhausts the standby chamber, and may be installed in the standby chamber.

  The batch-type heat treatment apparatus is not limited to the film forming process, but can be used for other processes such as an oxide film forming process, a diffusion process, and an annealing process.

  Although the case of the batch type heat treatment apparatus has been described in the above embodiment, the present invention is not limited to this and can be applied to all substrate processing apparatuses.

It is side surface sectional drawing which shows the batch type heat processing apparatus which is one embodiment of this invention. It is side surface sectional drawing which shows the time of boat carrying in.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Wafer (substrate), 10 ... Batch type heat processing apparatus (substrate processing apparatus), 11 ... Housing, 12 ... Standby chamber (airtight chamber), 13 ... Boat, 14 ... Wafer loading / unloading port, 15 ... Gate, 16 ... Boat loading / unloading port, 17 ... shutter, 18 ... heater unit, 19 ... processing chamber, 20 ... process tube, 21 ... gas introduction pipe, 22 ... exhaust pipe, 23 ... mounting table, 24 ... boat elevator, 25 ... upper mounting plate , 26 ... lower mounting plate, 27 ... guide rail, 28 ... feed screw shaft, 29 ... elevating body, 30 ... motor, 31 ... arm, 32 ... elevating shaft, 33 ... hollow part, 34 ... inner cylinder, 35 ... insertion Hole, 36 ... Bellows, 37 ... Elevator, 37a ... Main body, 37b ... Lid, 37c ... Seal ring, 37d ... Airtight chamber, 38 ... Magnetic fluid sealing device, 39 ... Bearing device, 40 ... Rotating shaft, 41 ... Boat Rotator Motor, 42 ... seal ring, 43 ... seal cap, 44 ... cooling device, 45 ... cooling water supply pipe, 46 ... variable flow control valve, 47 ... cooling water supply source, 48 ... cooling water, 49 ... water passage, 50 ... introduction side communication pipe, 51 ... outlet side communication pipe, 52 ... cooling water discharge pipe, 53 ... electric power supply wire, 54 ... tube, 55 ... supply line (leak check gas supply line), 56 ... helium gas supply device ( Leak check gas supply device), 57 ... exhaust pipe (exhaust system), 58 ... helium gas detector (leak check gas sensor), 59 ... nitrogen gas supply pipe.

Claims (1)

A processing chamber providing a space for processing a substrate;
An airtight chamber hermetically connected to the processing chamber;
An exhaust system for exhausting the atmosphere in the hermetic chamber;
A hollow airtight body provided so that most of the airtight chamber is located, wherein the hollow portion is isolated from the atmosphere of the airtight chamber;
A supply line for supplying a gas for leak check into the hermetic body;
A substrate processing apparatus comprising:

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