JPH0562905A - Surface treatment device - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a surface treatment apparatus capable of reliably suppressing the growth of a native oxide film of a semiconductor wafer carried into the apparatus. [Structure] Reactor 2 and carrying-in of an object to be treated in the reactor 2
A frame 1C having an internal space with an opening for carrying out is provided. The frame has a delivery section for delivering the object to be treated 18 to the outside, and an apparatus for carrying in and out the object to be treated with respect to the reaction furnace 2. In a surface treatment device that incorporates
It is characterized in that the entire internal space is always in an inert gas atmosphere, including when the object to be processed is delivered to the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface processing apparatus for performing diffusion processing or CVD processing on a semiconductor wafer.

[0002]

2. Description of the Related Art FIG. 2 schematically shows the structure of a conventional surface treatment apparatus of this type. In the figure, reference numeral 1 is a frame of the apparatus, which houses an upper frame which houses the vertical reaction furnace 2 and a transfer device which carries in and carries out semiconductor wafers carried in from the outside into the reaction furnace 2. It consists of a lower frame 1B, and the lower frame 1B has a door 1
A wafer delivery port 11A that is opened and closed at 9 is formed. Reference numeral 3 denotes a quartz tube of the vertical reactor 2, and a workpiece loading / unloading port 2A of the vertical reactor 2 is open in the lower frame 1B. 4 is an elevator, 5 is a boat having a plurality of shelves lined up and down, 6 is a wafer transfer device, 17
Is a carrier, and 20 is a carrier stage equipped with a rotary shelf 20A having a plurality of shelves. 21A and 21B are seal members. The carrier 17 accommodating a plurality of semiconductor wafers is carried into the rotary shelf 20A of the carrier stage 20 through the wafer transfer port 11A by an external transfer device (not shown). The wafer transfer device 6 takes out the semiconductor wafers one by one from the carrier 17 on the rotary shelf 20A and transfers them to the shelf of the boat 5 on the elevator 4. When this transfer is completed, the elevator 4 rises toward the reaction furnace, carries the boat 5 into the quartz tube 3 of the reaction furnace 2, and seals the workpiece loading / unloading port 2A via the seal member 21B.
The semiconductor wafer in the boat 5 is exposed to the reaction gas in the quartz tube 3, and the diffusion process or the CVD process is performed during this. When these processes are completed, the elevator 4 descends to the original position, and the semiconductor wafer in the boat 5 is transferred by the wafer transfer device 6 to the carrier 17 on the rotary shelf 20A. The semiconductor wafers in the boat 5 are all carriers 17
After the transfer is completed, the carrier 17 is carried out of the device by an external transfer device (not shown) and sent to the next step.

[0003]

In the illustrated apparatus, the atmosphere in the frame 1 is the atmosphere, and the semiconductor wafer is in the reaction furnace 2.
Since it is exposed to the atmosphere except when it is inside, natural oxide film growth occurs. In particular, since the temperature of the semiconductor wafer is high when it is taken out of the reaction furnace 2 or when it enters the reaction furnace 2, the degree of growth of the natural oxide film increases and the growth of the natural oxide film is suppressed. Is waiting time,
It is difficult if the processing waiting time is long.

As the degree of integration of semiconductors increases, the adverse effect of this natural oxide film increases, which causes variations in film formation and causes poor withstand voltage. Measures have been taken to control growth.

As a method for suppressing this type of natural oxide film,
(A) Double tube double elevator system, (b) N ₂ purge system, (c) Vacuum load lock system, (d) SMIF + N
₂ There is a so-called load lock method, but (a) ~
In the method of (c), the semiconductor wafer is cut off from the atmosphere in the process of raising / lowering the elevator 4 and loading / unloading the boat 5 to / from the reaction furnace 2, but the process of carrying the semiconductor wafer to the boat 5 and carrying it out of the apparatus. Since it is exposed to the atmosphere, the growth of the natural oxide film cannot be suppressed sufficiently,
In particular, when the device has a long transfer waiting time or a long processing waiting time in the device, the suppression effect is significantly reduced. SM of (d) above
In the IF + N ₂ load lock method, the inside of the frame 1 is purged with N ₂ and SMIF is used for the carrier transfer portion, so that the growth of the natural oxide film can be sufficiently suppressed, but there is a problem that it becomes expensive.

The present invention has been made in order to solve this problem, and the growth of the native oxide film of the semiconductor wafer carried into the device is surely suppressed in the device by simply taking simple measures. An object of the present invention is to provide a surface treatment device that can be used.

[0007]

In order to achieve the above object, the present invention comprises a reaction furnace and a frame having an internal space in which a material loading / unloading port of the reaction furnace is opened. In a surface treatment apparatus having a delivery section for delivering the processed material to the outside and incorporating a device for loading and unloading the processed material to and from the reaction furnace, including when the processed material is transferred to the outside. The internal space as a whole is cut off from the outside air and kept in an inert gas atmosphere at all times.

According to a second aspect of the present invention, there is provided an apparatus for loading / unloading an object to be processed into / from a reaction furnace, and an elevator for loading / unloading the object to be processed into / from the reaction furnace, and an object to be processed for delivering the object carrier to the outside. The article transfer device comprises a transfer device for transferring the object carrier from the transfer device to the stocker, and a transfer device for transferring the object to be processed from the stocker to the boat on the elevator.

According to another aspect of the present invention, the delivery section has a delivery section inert gas purge box capable of opening and closing the delivery port formed in the frame and a shutter, so that neither of them may open the delivery port. did.

According to a fourth aspect of the present invention, the shutter is a member of the object transfer device for transferring the object to the outside and also serves as a delivery plate on which the object is temporarily placed. did.

[0011]

According to the present invention, the inside of the frame in which the semiconductor wafer as the object to be processed moves or is on standby / moves is always in an inert gas atmosphere, including when it is delivered to the outside of the object to be processed. The object does not come into contact with the atmosphere before and after the treatment, and the growth of the natural oxide film is surely prevented.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a frame 1 is an upper frame 1A and a lower frame 1 containing a transfer device for loading and unloading a semiconductor wafer loaded into the reaction furnace 2 from the outside.
In addition to the elevator 4, the wafer transfer device 6, and the carrier stocker 7 in the lower frame 1C,
A carrier transfer device 8 and an elevating device 9 forming a wafer transfer device are housed.

The lower frame 1C of the present embodiment has a shape having a step portion 1c facing the bottom 1a of the upper frame 1A and having a wafer transfer port 11 formed therein. 12 and 13
Are seal members provided on the upper surface peripheral portion and the lower surface peripheral portion of the wafer delivery port 11, respectively. Reference numeral 14 denotes a wafer delivery part N ₂ purge box capable of closing the wafer delivery port 11 to the outside, which has a flange 14A facing the peripheral edge of the upper surface of the wafer delivery port 11 and has an upper frame 1A.
It is supported in a suspended manner by a rod 15A of a vertically elevating device (cylinder) 15 disposed inside. The rod 15A has a built-in N ₂ gas pipe 16 that opens into the wafer transfer unit N ₂ purge box 14, and the N ₂ gas pipe 16 is connected to an N ₂ gas source (not shown).
The wafer transfer part N ₂ purge box 14 has an internal space large enough to accommodate one carrier 17.

Reference numeral 10 denotes a delivery plate of the wafer delivery device, which also functions as a shutter for the wafer delivery port 11 and is attached to the end of the rod 9A of the vertically elevating device 9 so that the wafer delivery port 11 can be closed from the inner surface side. There is.

In the present embodiment, the inside of the lower frame 1C communicates with an N ₂ gas source (not shown) through a pipe, and the entire inside is purged with N ₂ gas.

When the carrier 17 shown in FIG. 2 is loaded into the lower frame 1C, (1) the elevating device 15 operates so as to pull up the rod 15A, and the wafer transfer part N ₂ purge box 14 moves from the position shown in the figure. It is pulled up by a predetermined height. At this time,
The delivery plate 10 is provided with a wafer transfer port 1 via a seal member 13.
1 is airtightly closed.

(2) Wafer transfer part N _{2 When the} purge box 14 is pulled up by a predetermined height, an external transfer device (not shown) is activated to transfer the carrier 17 to the transfer plate 1.
0, and when this transfer is completed, the elevating device 15 operates so as to push down the rod 15A, the wafer transfer unit N ₂ purge box 14 descends to the position shown, and the wafer is transferred via the seal member 12. The delivery port 11 is airtightly closed.

(3) When this operation of the elevating device 15 is finished, N ₂ gas is supplied from the N ₂ gas source into the wafer transfer section N ₂ purge box 14 for a predetermined time or until the oxygen concentration drops to a predetermined value. to, the wafer transfer unit N ₂ purge box 14 N ₂ gas-purged, replacing the air in the wafer transfer unit N ₂ purge box 14 with N ₂ gas.

(4) When the above predetermined time elapses or when the oxygen concentration decreases to a predetermined value, the elevating device 9 operates to lower the rod 9A thereof, and the transfer plate 10 keeps the carrier 17 mounted thereon to a predetermined height. To descend. When this lowering operation is completed, the carrier transfer device 8 transfers the carrier 17 on the delivery plate 10 to the empty shelf of the carrier stocker 7. (5) During this transfer, the elevating device 9 is moved back and its rod 9A is raised, and the delivery plate 10 hermetically closes the wafer delivery port 11 via the seal member 13.

(6) The above operations (1) to (5) are repeated until the carrier 17 is carried into each shelf of the carrier stocker 7 or a plurality of predetermined shelves. At this time, the wafer transfer device 6 is operated. The semiconductor wafers are taken out one by one from the carrier 17 of the carrier stocker 7 and transferred to the shelf of the boat 5 on the elevator 4.

(7) When this transfer operation is completed, the elevator 4 rises and the boat 5 moves to the quartz tube 3 of the reaction furnace 2.
Carrying in the inside, diffusion processing of semiconductor wafer or CVD
Processing is performed. After this process, elevator 4
Moves back to its original position.

After (8), the semiconductor wafer in the boat 5 is transferred to the carrier 17 on the carrier stocker 7 by the wafer transfer device 6.

(9) When the transfer to each carrier 17 is completed, the transfer plate 10 descends with the wafer transfer port 11 sealed by the wafer transfer section N ₂ purge box 14 and the carrier is transferred onto the transfer plate 10. The carrier 17 is transferred by the transfer device 8, and after the transfer, the transfer plate 10 is lifted to seal the wafer transfer port 11 from below. Wafer delivery port 1
After this sealing of No. 1, the wafer transfer part N ₂ purge box 1
4 is moved up, and the carrier 17 on the delivery plate 10 is carried to the next step by a transfer device (not shown). This operation is repeated as many times as the number of carriers 17.

As described above, in the present embodiment, the delivery plate 10 hermetically closes the wafer delivery port 11 while the wafer delivery unit N ₂ purge box 14 is separated from the wafer delivery port 11. 10 is a wafer delivery port 11
Since the wafer transfer part N ₂ purge box 14 hermetically closes the wafer transfer port 11 while the carrier transfer part is separated from the device, the inside of the lower frame 1C communicates with the outside air even when the carrier 17 is carried in and out of the apparatus. it is not, once, throughout the N ₂ gas purge has been lower frame 1C always maintains the N ₂ gas purge state.

Therefore, in this embodiment, the lower frame 1C is used.
The semiconductor wafer that was loaded into the
Since it is carried into the reaction furnace 2 and is carried from the reaction furnace 2 to the delivery port 11 without being exposed to the atmosphere even after the processing, even if the waiting time for transfer in the apparatus or the processing waiting time is long, the natural oxide film Growth is certainly prevented.

Further, in this embodiment, neither the delivery part N ₂ gas purge box 14 nor the delivery plate 10 opens the wafer delivery port 11, and the wafer delivery port 11 is always airtightly closed to the outside. Therefore, particles are prevented from entering the frame 1C from the outside, and there is no possibility that particles entering from the outside adhere to the surface of the semiconductor wafer.

As described above, in this embodiment, only by providing the N ₂ gas purge box 14 and the delivery plate 10 in the delivery section for delivering the semiconductor wafer to the outside, the growth of the natural oxide film can be sufficiently suppressed, and the delivery from the outside can be prevented. It is possible to prevent particles from entering.

[0029]

As described above, according to the present invention, the inside of the frame in which the semiconductor wafer, which is the object to be processed, moves or stands by / moves at all times, including when it is delivered to the outside of the object to be processed.
Since it is in the inert gas atmosphere, the growth of the natural oxide film can be reliably prevented, the reliability of the highly integrated semiconductor device can be improved, and the manufacturing yield can be greatly improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional surface treatment apparatus.

[Explanation of symbols]

1 Frame 1A Upper Frame 1C Lower Frame 2 Reactor 3 Quartz Tube 4 Elevator 5 Boat 6 Wafer Transfer Device 7 Carrier Stocker 8 Carrier Transfer Device 9 Elevating Device for Delivery Device 10 Shutter that also serves as a Delivery Plate 11 Delivery Ports 12, 13 Seals Member 14 Delivery part N ₂ Purge box 15 Lifting device 16 N ₂ Gas pipe 17 Carrier

Claims (4)

[Claims] 1. A reaction furnace and a material to be processed carried into the reaction furnace.
A frame having an internal space with an opening for carrying out is provided, the frame has a delivery section for delivering the object to be treated to the outside, and a device for loading and unloading the object to be treated is incorporated. A surface treatment apparatus characterized in that the entire internal space is cut off from the outside air and maintained in an inert gas atmosphere at all times, including when the object to be treated is delivered to the outside. 2. An apparatus for loading / unloading an object to be processed into / from a reaction furnace includes an elevator for loading / unloading the object to be processed into and out of the reaction furnace, and an apparatus for transferring an object to be processed which transfers the object to be processed carrier to the outside. And a transfer device that transfers the object carrier from the delivery device to the carrier stocker, and a transfer device that transfers the object carrier from the carrier stocker to the boat on the elevator. 1. The surface treatment apparatus according to 1. 3. The delivery part has a delivery part inert gas purge box capable of opening and closing the delivery port formed in the frame and a shutter, and both do not open the delivery port. The surface treatment apparatus according to claim 1. 4. The shutter is a member of the object transfer device for transferring the object to the outside, and also functions as a delivery plate on which the object is temporarily placed. The surface treatment apparatus according to claim 1.