JPH0870028A - Semiconductor manufacturing device and atmosphere intrusion prevention method - Google Patents

Abstract

PURPOSE: To improve productivity by improving the transport efficiency of a wafer cassette and a wafer, at the same time prevent atmosphere from entering a semiconductor manufacturing device during the carry-in/out process of the wafer cassette, then prevent a natural oxide film from being formed when transferring the wafer in the device and at standby, and prevent the wafer from being contaminated. CONSTITUTION: In a semiconductor manufacturing device with a boat elevator for inserting and withdrawing a boat 9 into and from a reaction oven, a cassette stocker 2, a buffer cassette stocker 3, a wafer transfer machine 4 for transferring the wafer between the boat 9 and the cassette stocker, and a cassette loader 1 for transferring the wafer cassette between the outside, the cassette stocker 2, and the buffer cassette stocker, the inside of an enclosure is screened into a cassette chamber 22 and a cassette transfer machine 28 is provided for transferring the wafer cassette. Or, the cassette chamber is brought adjacent to a transport chamber 23, a gate valve 30 for carrying the wafer cassette is provided, a gate valve 31 for carrying wafers is provided at the screening valve, and the inside of the enclosure is partitioned into small chambers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus for manufacturing a semiconductor element from a silicon wafer, and a method for preventing atmospheric infiltration into the semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art As a process for producing a semiconductor, there is a process of depositing a film on a wafer by a vapor phase growth reaction, diffusion of impurities such as phosphorus or boron, and a process of heat-treating the wafer.

An outline of a semiconductor manufacturing apparatus, particularly a semiconductor manufacturing apparatus having a vertical furnace will be described with reference to FIGS. 2 and 3.

Reference numeral 1 is a cassette loader located in front of the semiconductor manufacturing apparatus, 2 is a cassette stocker, 3 is a buffer cassette stocker, 4 is a wafer transfer machine, 5 is a boat elevator, 6 is a reaction furnace, and 20 is a housing.

Wafers are transferred while they are loaded in the wafer cassette 13. The wafer cassette 13 is mounted on the cassette loading / unloading machine 7 of the cassette loader 1 through a cassette loading / unloading port 26 provided in the semiconductor manufacturing apparatus by an operator or a cassette transportation robot (not shown) installed in a factory. Placed. The cassette insertion / ejection machine 7 moves up and down,
The cassette stocker 2 and the buffer cassette stocker 3
The wafer cassette 13 is inserted into and removed from the cassette storage shelf at the required position.

The wafer transfer machine 4 has a chucking head 8 which can be raised and lowered, can be rotated, and can be moved in the horizontal direction, and the boat elevator 5 receives the boat 9 via a boat cap 11. The boat 9 is moved up and down and charged into the reaction furnace 6. The wafer transfer device 4 is a boat 9
In the descending state, the chucking head 8 transfers the wafer 10 from the wafer cassette of the cassette stocker 2 to the boat 9.

The boat 9 is loaded into the reaction furnace 6 by the boat elevator 5, the wafer 10 is heated in the reaction furnace 6, and the inside of the reaction furnace 6 is kept for a certain time so that the wafer 10 reaches the reaction temperature. Vacuum to control to a predetermined degree of vacuum,
A reaction gas is introduced into the reaction furnace 6 to perform a required process. After the heat treatment, the inside of the reaction furnace 6 is replaced with an inert gas, the boat 9 is lowered by the boat elevator 5, and the boat 9 is pulled out from the reaction furnace 6. The boat 9 and the wafer 10 are cooled outside the furnace, and in the lowered state of the boat 9, the wafer transfer device 4 transfers the wafer 10 from the boat 9 to the wafer cassette of the cassette stocker 2.

Further, the wafer 10 to be processed next is transferred to the boat 9 by the wafer transfer machine 4. Reference numeral 12 in the figure denotes a furnace port shutter that shuts off heat radiation from the reaction furnace 6 when the boat 9 is pulled out.

Next, the operation of the cassette loader 1 will be briefly described. If the cassette stocker 2 has a cassette storage shelf that has not been stored, the cassette inserter / unloader 7 is moved up and down to the cassette storage shelf that has not been stored, and the wafer cassette 13 is stored in the cassette stocker 2. When the required number of wafer cassettes 13 are stored in the cassette stocker 2,
During the wafer heating process in the reaction furnace 6, the cassette loader 1 drives the cassette loading / unloading device 7 to store the wafer cassette 13 in which the wafer for the next process is loaded in the buffer cassette stocker 3.

When the processing of the wafers stored in the cassette stocker 2 is completed, the wafer cassette 13 stored in the buffer cassette stocker 3 is transferred to the cassette stocker 2 by the cassette loader 1 via the cassette loading / unloading machine 7. And is subjected to the next processing.

[0011]

As described above, in the conventional semiconductor manufacturing apparatus, the cassette stocker 2 and the buffer cassette stocker 3 are arranged vertically, and the cassette stocker 2 and the buffer cassette stocker 3 are arranged between them. In order to transfer the wafer cassette 13, two cassettes are carried out, and the transfer operation has to be repeated a plurality of times, which is very time consuming. Further, in the conventional semiconductor manufacturing apparatus, when the wafer cassette 13 is loaded and unloaded, a large amount of air enters from the cassette loading / unloading port. Furthermore, in the semiconductor manufacturing apparatus, with the transfer operation of the wafer cassette 13 between the cassette stocker 2 and the buffer cassette stocker 3,
Further, the buffer cassette stocker 3 may be kept waiting for a long time. Therefore, a natural oxide film is formed on the surface of the wafer while the wafer is on standby in the buffer cassette stocker 3 and during the transfer operation of the wafer cassette 13 between the cassette stocker 2 and the buffer cassette stocker 3.

Further, particles and other pollutants (metal substances such as Na, Al, Cu and the like) are suspended even in a clean room, which is kept normally. Therefore, the wafer may be contaminated during standby or during transfer of the wafer cassette 13. When these particles and other contaminants adhere to the wafer during the semiconductor manufacturing process, they cause disconnection of the manufactured semiconductor element, deterioration of electrical characteristics, and the like.

Further, when an oxide film is formed on the surface of a wafer in a diffusion apparatus, if there is a contaminant such as a metal substance on the surface of the wafer, only the contaminated portion has an increased oxidation rate and the film thickness is locally increased. However, there is a problem in that the quality of the film is also affected.

In view of the above situation, the present invention improves the wafer cassette / wafer transfer efficiency, improves the productivity of the semiconductor manufacturing apparatus, and allows atmospheric air to enter the semiconductor manufacturing apparatus during the loading / unloading process of the wafer cassette. It is an object of the present invention to prevent the formation of a natural oxide film and the contamination of wafers during the transfer and standby of the wafers in the semiconductor manufacturing apparatus.

[0015]

SUMMARY OF THE INVENTION The present invention comprises a reactor, a boat elevator for loading and unloading a boat into the reactor, a cassette stocker, a buffer cassette stocker, the boat and the cassette stocker. In a semiconductor manufacturing apparatus equipped with a wafer transfer machine for transferring wafers between wafers, a cassette loader for transferring wafer cassettes between the outside and the cassette stocker, and a buffer cassette stocker, at least the inside of the housing is It is divided into a cassette transfer chamber that houses the cassette loader and a cassette room that houses the cassette stocker and buffer cassette stocker.A gate valve is provided on the partition wall between each chamber, and an inert gas inlet pipe and exhaust pipe are connected to each chamber. Related semiconductor manufacturing equipment,
Alternatively, a reactor in a housing, a boat elevator for loading and unloading a boat into the reactor, a cassette stocker, a buffer cassette stocker, and a wafer transfer machine for transferring wafers between the boat and the cassette stocker. In a semiconductor manufacturing apparatus equipped with a cassette loader that transfers wafer cassettes between the outside and the cassette stocker and buffer cassette stocker, the inside of the housing is partitioned into a cassette chamber that stores at least the cassette stocker and the buffer cassette stocker. , The cassette stocker and the buffer cassette stocker are provided so as to face each other, and a cassette transfer machine for transporting a wafer cassette is provided between the cassette stocker and the buffer cassette stocker, and between the cassette transfer machine and the cassette loader. Being able to exchange wafer cassettes In relation to the semiconductor manufacturing apparatus, the cassette chamber in such a semiconductor manufacturing apparatus is adjacent to the cassette transfer chamber and the transfer chamber that houses the wafer transfer machine, and is used as a partition wall between the cassette chamber and the cassette transfer chamber. A semiconductor manufacturing device in which a gate valve for wafer cassette transfer is installed, a gate valve for wafer transfer is installed on the partition wall between the cassette chamber and the transfer chamber, and both gate valves are opened and closed so that either one of them is closed. Further, the wafer is transferred between the reactor, the boat elevator for loading and unloading the boat into the reactor, the cassette stocker, the buffer cassette stocker, and the boat and the cassette stocker. A wafer transfer machine and a cassette loader for transferring wafer cassettes between the outside and the cassette stocker or buffer cassette stocker are provided. In a semiconductor manufacturing apparatus in which the cassette stocker and the buffer cassette stocker are housed in a cassette chamber, the cassette loader is housed in a cassette transfer chamber, and an inert gas introduction pipe and an exhaust pipe are connected to the cassette chamber and the cassette transfer chamber, respectively. In addition, the present invention relates to a method for preventing atmospheric infiltration, in which the amount of inflow of the inert gas from the cassette chamber is equal to or larger than the exhaust flow rate of both the cassette chamber and the cassette transfer chamber.

[0016]

The inside of the housing is partitioned into at least a cassette transfer chamber for accommodating the cassette loader and a cassette chamber for accommodating the cassette stocker and the buffer cassette stocker, and the transfer of the wafer cassette between the chambers is performed via the gate valve. Therefore, replacement of inert gas for each unit becomes easy,
The atmosphere can be prevented from entering the inside of the semiconductor manufacturing apparatus. Further, by disposing the cassette stocker and the buffer cassette stocker so as to face each other, the transfer operation can be simplified, the transfer time can be shortened, and at least one of the gate valves is provided in the cassette chamber. By operating so as to be in the closed state, the atmosphere cannot enter the inside of the cassette chamber, and the entry of the atmosphere can be prevented. Furthermore, by setting the flow rate of the inert gas introduced into the cassette chamber to be equal to or higher than the exhaust flow rate, it is possible to prevent the infiltration of the atmosphere from the cassette loading / unloading port.

[0017]

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

In FIG. 1, those having the same functions as those shown in FIG. 2 are designated by the same reference numerals.

Inside the housing 20 of the semiconductor manufacturing apparatus, a cassette transfer chamber 21 located on the lower front side, a cassette chamber 22 located above the cassette transfer chamber 21, and the cassette chamber 2
2, a transport chamber 23 located below the cassette transfer chamber 21, a heater chamber 24 located adjacent to the transport chamber 23 and located in the upper rear part of the apparatus, and a boat storage chamber 25 located below the heater chamber 24. To do.

A cassette carry-in / carry-out port 26 is provided in a portion of the housing 20 facing the cassette transfer chamber 21, and a front shutter 27 is provided at the cassette carry-in / carry-out port 26. The front shutter 27 has a structure in which the door body is pushed upward from below and opens. Also, the cassette transfer room 21
A cassette loader 1 is provided inside, and a nitrogen gas introduction pipe 34 and an exhaust pipe 35 having a stop valve 36 are connected to the cassette transfer chamber 21.

Inside the cassette chamber 22, the buffer cassette stocker 3 is provided on the front side and the cassette stocker 2 is provided on the rear side.
And a cassette transfer machine 28 is provided between the buffer cassette stocker 3 and the cassette stocker 2. The cassette transfer machine 28 has a cassette holder 40 that can move up and down, rotate, and can move back and forth in the horizontal direction. The cassette holder 40 is driven to drive the wafer cassette 13 between the buffer cassette stocker 3 and the cassette stocker 2. Is transferred.

Partition wall 2 defining the cassette chamber 22
9 is a gate valve 30 at the boundary with the cassette transfer chamber 21.
The wafer cassette 13 loaded from the outside by the cassette loader 1 via the gate valve 30 is stored in the buffer cassette stocker 3, and the wafer cassette 13 of the buffer cassette stocker 3 is unloaded to the outside.

The cassette stocker 2 is designed to move up and down over the cassette chamber 22 and the transfer chamber 23, and a gate valve 31 is provided at an insertion portion of the partition wall 29 of the cassette stocker 2. There is. Further, a nitrogen gas introducing pipe 37 and an exhaust pipe 38 having a stop valve 39 are connected to the cassette chamber 22.

A clean unit 33 is provided on a partition wall 32 for partitioning the cassette transfer chamber 21 and the transfer chamber 23, and the wafer transfer device 4 is provided at the rear of the transfer chamber 23 adjacent to the boat storage chamber 25. The wafer transfer device 4 is provided to transfer the wafers 10 between the cassette stocker 2 and the boat 9 by the wafer transfer machine 4. Further, the transfer chamber 23 has an exhaust pipe 4 provided with a nitrogen gas introduction pipe 41 and a stop valve 43.
2 are connected.

The reaction furnace 6 is housed in the heater chamber 24, and a gate valve 46 is provided at the furnace opening of the reaction furnace 6.

A gate valve 45, which is opened at the time of wafer transfer, is provided on a partition wall 44 that partitions the transfer chamber 23 and the boat storage chamber 25. A boat elevator (not shown) is provided in the boat accommodating chamber 25, and the boat 9 is loaded into and withdrawn from the reaction furnace 6 via the gate valve 46. Further, a nitrogen gas introduction nozzle 47 provided at the tip of a nitrogen gas introduction pipe (not shown) is provided in the boat storage chamber 25.
Is provided in parallel with the boat 9 in a lowered state, and is further connected to an exhaust pipe 48 having a stop valve 49. A large number of gas outlets are formed in the nitrogen gas introduction nozzle 47 so that the nitrogen gas is dispersed and supplied into the boat storage chamber 25.

As described above, the cassette transfer chamber 21,
In the cassette chamber 22, the transfer chamber 23, and the boat storage chamber 25,
Since the nitrogen gas introduction pipe and the exhaust pipe are connected to each other, each chamber can be made to have an inert gas (nitrogen gas) atmosphere.

Next, the wafer cassette and wafer transfer operation will be described.

The front shutter 27 is opened, and an operator or a cassette carrying robot (not shown) places the wafer cassette 13 on the cassette loading / unloading machine 7. Then, the front shutter 27 is closed, the gate valve 30 is opened, and the cassette insertion / ejection machine 7 is lifted to move the wafer cassette 1
3 is fed into the cassette chamber 22. The cassette holder 40 of the cassette transfer machine 28 receives the wafer cassette 13 from the cassette loading / unloading machine 7, and conveys the received wafer cassette 13 to the cassette stocker 2 or the buffer cassette stocker 3. The cassette inserter / unloader 7 descends and the gate valve 30 is closed.

Again, the front shutter 27 is opened, the wafer cassette 13 is carried in, and the above-mentioned wafer cassette carrying operation is repeated. The transfer of the wafer 10 from the cassette stocker 2 to the boat 9 is performed as follows.

The gate valve 31 is opened, the cassette stocker 2 is lowered to the position shown by the chain double-dashed line in the figure, and the gate valve 31 is closed. The boat 9 is in a lowered state and faces the cassette stocker 2. The gate valve 45 is opened, and the chucking head 8 of the wafer transfer device 4 transfers the wafer 10 in the cassette stocker 2 to the boat 9.

When the transfer of the wafer 10 to the boat 9 is completed, the gate valve 45 is closed, the gate valve 46 is opened, the boat 9 is loaded into the reaction furnace 6, and the wafer 10 is transferred.
Is processed.

When the processing of the wafer 10 is completed, the gate valve 46 is opened, the boat 9 is lowered, the gate valve 46 is closed, and the wafer 10 is cooled to the required temperature in the boat storage chamber 25. Done. Next, the gate valve 45 is opened, and the wafer 1 is transferred from the boat 9 to the cassette stocker 2 by the wafer transfer machine 4.
0 transfer is performed.

When the transfer of the wafer 10 to the cassette stocker 2 is completed, the gate valve 45 is closed, the gate valve 31 is opened, the cassette stocker 2 is raised, and is housed in the cassette chamber 22. The valve 30 is opened, and the cassette stocker 2 is operated by the cassette transfer machine 28.
The wafer cassette 13 loaded with the processed wafers 10 is transferred to the cassette loader 1, the front shutter 27 is opened, and the wafer cassette 13 is unloaded to the outside of the housing 20 through the cassette loading / unloading port 26. To be done.

The above operation is repeated and wafers are sequentially processed.

The opening of the cassette carry-in / carry-out port 26 is set so as not to come into contact with the housing 20 when an operator or a cassette transfer robot transfers the wafer cassette 13 to and from the cassette loader 1. Cassette loading / unloading port 26
For an 8-inch wafer, an opening area of about 700 mm × 500 mm is required. Therefore, a standby inflow from the outside of the semiconductor manufacturing apparatus is inevitable when loading / unloading the wafer cassette, but as described above, in the present embodiment, the cassette loader 1 is used.
Is stored in a small space in the cassette transfer chamber 21, so that a large amount of atmosphere does not enter the semiconductor manufacturing apparatus through the cassette transfer chamber 21.

Further, the inside of the cassette transfer chamber 21 can be replaced with nitrogen gas by the nitrogen gas introducing pipe 34 and the exhaust pipe 35,
After replacement with nitrogen gas, the wafer cassette 13 is moved in and out of the cassette chamber 22 for storing the buffer cassette stocker 3 through the gate valve 30, and the opening area of the gate valve 30 may be about 700 mm × 300 mm. It is reduced to 3/5 compared to the carry-in / carry-out port 26.

The gate valve 30 of the cassette chamber 22 opens after the inside of the cassette transfer chamber 21 is replaced with nitrogen gas,
The wafer cassette 13 is loaded by the cassette loader 1, but the cassette transfer chamber 2 is used to shorten the transfer time.
1 As described above, the opening area of the gate valve 30 is small even if the nitrogen gas in the inside is not replaced sufficiently or not at all, and the atmosphere is introduced by further circling the gate valve 30 from the cassette transfer chamber 21. In addition, a large amount of nitrogen gas is introduced into the cassette chamber 22 from the nitrogen gas introduction pipe 37, for example, 200 to 300 l / min, the stop valve 39 is closed, and the nitrogen gas introduction pipe 34 is used to transfer the cassette. The flow of nitrogen gas into the chamber 21 is, for example, 0 to 20 l.
If a small amount of / min is flown and the stop valve 36 is opened so that the nitrogen gas flows from the cassette chamber 22 to the cassette transfer chamber 21, the nitrogen gas will flow out from the cassette loading / unloading port 26 to enter the atmosphere. And the nitrogen gas replacement time in the cassette transfer chamber 21 can be shortened, and the formation of a natural oxide film on the wafer surface can be significantly suppressed.

The stop valve 39 may be slightly opened and the stop valve 43 may be completely closed. The point is that the nitrogen gas introduction pipe 37 is more than the total exhaust flow rate from the cassette chamber 22 and the cassette transfer chamber 21. It suffices if the flow rate of the introduced nitrogen gas from is sufficiently high.

Further, in the transfer of the wafer cassette 13 between the cassette stocker 2 and the buffer cassette stocker 3, the cassette stocker 2 and the buffer cassette stocker 3 are positioned so as to face each other, and the cassette transfer machine 28 is provided between them. Therefore, the amount of movement of the cassette holder 40 in the vertical direction is significantly reduced, and the transport time can be greatly shortened. Further, since the cassette stocker 2 moves up and down and moves to the transfer position of the wafer 10, the time required for the transfer of the wafer including the transfer of the wafer cassette is reduced in combination with the decrease in the vertical movement amount of the cassette holder 40. Can be shortened.

As described above, the front shutter 27 has a structure in which it is pushed upward from the bottom to open. This is to prevent an accident that the front shutter 27 is lowered and the wafer cassette, the hand of an operator, or the like is caught when the power supply to the semiconductor manufacturing apparatus is cut off due to an accident such as a power failure. is there. Therefore, when the power supply to the semiconductor manufacturing apparatus is cut off, the front shutter 27 remains open and the air flows into the atmosphere through the cassette loading / unloading port 26.

As described above, the partition wall 32 and the clean unit 33 are provided to face the cassette loading / unloading port 26 in order to prevent the atmospheric air from entering the entire semiconductor manufacturing apparatus in response to the inflow of the atmospheric air. A gate valve 30 serving as a loading / unloading port for the cassette chamber 22 is provided above. Further, if the operation sequence is such that the gate valve 30 is in a closed state at the time of a power failure or one of the gate valve 30 and the gate valve 31 is always in a closed state, the gate valve is open. By utilizing the characteristic of the operation that the open state is maintained and the closed state is maintained when the closed state, it is possible to obtain the effect of preventing the invasion of the atmosphere into the transfer chamber 23 in any state.

Although the inert gas is nitrogen gas in the above embodiment, an inert gas such as argon gas or helium gas may be used, and a cassette chamber for storing the cassette stocker and the buffer cassette stocker may be used. By implementing the conventional example shown in FIGS. 2 and 3 and by providing a plurality of gate valves in the cassette chamber and selectively opening and closing, a large amount of atmospheric air can be prevented from entering from the cassette loading / unloading port. It goes without saying that you can do it.

Further, in order to improve the transfer efficiency of the wafer cassette with respect to the cassette stocker and the buffer cassette stocker, the cassette stocker and the buffer cassette stocker are arranged so as to face each other, and the transfer of the wafer cassette between both stockers is performed by the cassette transfer machine. The transfer to the outside is performed through the transfer of the wafer cassette between the cassette transfer machine and the cassette loader.However, if it has such a configuration, the cassette chamber is not necessarily the cassette transfer chamber. It does not need to be provided above, but may be provided laterally adjacently.

Furthermore, in the above embodiment, the cassette stocker 2 is moved into the transfer chamber 23, and then the wafer transfer machine 4 is moved.
Although the wafers were transferred between the cassette stocker 2 and the boat 9 by means of the wafer transfer machine 4, even if the wafers were directly transferred between the cassette stocker 2 and the boat 9 in the cassette chamber 22 through the gate valve. Good.

[0046]

As described above, according to the present invention, the transfer of wafer cassettes between the cassette stocker and the buffer cassette stocker, and the wafer transfer work between the cassette stocker and the boat are simplified. Transport time is shortened, processing time can be significantly shortened, productivity is improved, and residence time in the semiconductor manufacturing equipment is shortened, and wafer cassettes are transferred between the outside and the semiconductor manufacturing equipment. Due to the large decrease in the amount of invasion of the atmosphere, formation of a natural oxide film on the wafer surface is suppressed, and product quality and yield can be improved.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram showing a conventional example.

FIG. 3 is a perspective view showing a conventional example.

[Explanation of symbols]

 1 cassette loader 2 cassette stocker 3 buffer cassette stocker 4 wafer transfer machine 5 boat elevator 6 reactor 7 cassette insertion / extraction machine 9 boat 21 cassette transfer room 22 cassette room 23 transfer room 24 heater room 25 boat storage room 26 cassette loading / unloading port 28 cassette transfer machine 30 gate valve 31 gate valve 34 nitrogen gas introducing pipe 35 exhaust pipe 37 nitrogen gas introducing pipe 38 exhaust pipe 41 nitrogen gas introducing pipe 42 exhaust pipe

Front page continued (72) Inventor Kenichi Kamiya, 3-14-20 Higashi-Nakano, Nakano-ku, Tokyo Kokusai Electric Co., Ltd.

Claims (7)

[Claims] 1. A wafer is transferred between a reactor, a boat elevator for loading and unloading a boat into the reactor, a cassette stocker, a buffer cassette stocker, and the boat and the cassette stocker. In a semiconductor manufacturing apparatus equipped with a wafer transfer machine and a cassette loader for transferring wafer cassettes between the outside and the cassette stocker or buffer cassette stocker, a cassette transfer chamber for accommodating at least the cassette loader inside a housing. And a cassette chamber for storing a cassette stocker and a buffer cassette stocker, a gate valve is provided on a partition wall between the chambers, and an inert gas introduction pipe and an exhaust pipe are communicated with each chamber. apparatus. 2. A wafer is transferred between a reactor, a boat elevator for loading and unloading a boat into the reactor, a cassette stocker, a buffer cassette stocker, and the boat and the cassette stocker. In a semiconductor manufacturing apparatus equipped with a wafer transfer machine and a cassette loader for exchanging wafer cassettes between the outside and the cassette stocker or buffer cassette stocker, at least the cassette stocker and the buffer cassette stocker are housed inside the housing. A cassette chamber and a buffer cassette stocker are provided so as to face each other, and a cassette transfer machine for transferring a wafer cassette is provided between the cassette stocker and the buffer cassette stocker. The cassette transfer machine and the cassette loader are provided. Wafer cassettes are exchanged with A semiconductor manufacturing apparatus characterized by being configured so that it can be obtained. 3. A cassette chamber is provided adjacent to a cassette transfer chamber and a transfer chamber accommodating a wafer transfer machine, and a gate valve for transferring a wafer cassette is provided on a partition wall between the cassette chamber and the cassette transfer chamber. 3. The semiconductor manufacturing apparatus according to claim 1, wherein a gate valve for wafer transfer is provided on a partition wall between the transfer chamber and the transfer chamber, and both gate valves are opened / closed so that one of the gate valves is closed. 4. The semiconductor manufacturing apparatus according to claim 1, wherein the cassette chamber is arranged above the cassette transfer chamber. 5. The semiconductor manufacturing apparatus according to claim 3, wherein the cassette chamber is arranged above the cassette transfer chamber. 6. The semiconductor according to claim 4, wherein the cassette stocker can be moved up and down between the cassette chamber and the transfer chamber, and the wafer transfer machine is arranged to face the picking boat at the lowered position of the cassette stocker. Manufacturing equipment. 7. A wafer is transferred between a reactor, a boat elevator for loading and unloading a boat into the reactor, a cassette stocker, a buffer cassette stocker, and the boat and the cassette stocker. It is equipped with a wafer transfer machine and a cassette loader for transferring wafer cassettes between the outside and the cassette stocker or buffer cassette stocker. In a semiconductor manufacturing apparatus that is housed in a chamber and has an inert gas introduction pipe and an exhaust pipe connected to the cassette chamber and the cassette transfer chamber, respectively, the amount of the inflow of the inert gas from the cassette chamber is determined by the cassette chamber Atmospheric intrusion prevention in semiconductor manufacturing equipment, characterized by being equal to or higher than the exhaust flow rate of the chamber How to stop.