KR100243975B1 - Automatic transporting apparatus for clean room - Google Patents

Abstract

The present invention relates to an unmanned conveying apparatus used for conveying a semiconductor wafer or an electronic material substrate.

The present invention suppresses the generation of a natural oxide film on the surface of a semiconductor wafer, even if the transfer is caused by itself or a long time interruption is inevitable due to a transfer, a conveyance paper, etc. with a semiconductor wafer or the like mounted thereon. An object of the present invention is to provide an unmanned conveying device that can be used.

In the unmanned conveying device which carries a conveyed object in a ground-side installation and runs by itself to a destination, the conveyed object is accommodated in the conveyance box 40 and conveyed, and this container carries out supply gas passage 53 so that the internal atmosphere can be replaced. It is characterized in that it is connected to the inert gas storage part (nitrogen gas container) 50 through.

Description

Unmanned Transfer Device for Clean Room

1 is a block diagram showing a state of use of the embodiment of the present invention.

2 is a diagram showing a specific configuration of an unmanned carrier in the above embodiment.

3 is a view showing another embodiment of the present invention.

4 is a diagram showing a relationship between growth and time of natural oxide film of a silicon semiconductor wafer.

5 is a diagram showing a relationship between resistivity and time caused by the formation of a natural oxide film of a silicon semiconductor wafer.

* Explanation of symbols for main parts of the drawings

1: wafer cassette 2: semiconductor wafer

10, 20: semiconductor manufacturing apparatus 30: driverless transport

30A: Balance body 30B: Ceiling plate

31: Robot for carrying 40: Transfer box

42: lid 43: sensor for cargo detection

44 gas inlet 45 exhaust port

50: inert gas container 53: supply gas valve

54 exhaust valve 60 controller

70: timekeeping circuit

TECHNICAL FIELD This invention relates to the unmanned conveying apparatus used for conveyance of a semiconductor wafer and the board | substrate for electronic materials.

The manufacture of semiconductor ICs is always performed in a clean room in which air is cleaned. When the degree of integration of semiconductor integrated circuits increases, a natural oxide film formed on the surface of a semiconductor wafer or an electronic material substrate becomes a problem. It is necessary to suppress the growth of this natural oxide film.

4 and 5 are described in a paper published in the Ultra LSI Ultra Clean Technology Symposium (November 19, 1990), and FIG. 4 is a diagram showing the natural oxide film (oxygen and moisture in air) of a silicon semiconductor wafer. FIG. 5 is a diagram showing the relationship between resistivity and time.

As is apparent from FIG. 4, when the silicon semiconductor wafer is exposed to the atmosphere, the growth of the oxide film becomes remarkable after 100 to 200 minutes, and the resistivity rapidly increases after about 1 hour as shown in FIG.

In the clean room, an unmanned transport vehicle equipped with a robot for transporting a semiconductor wafer is used to transport the semiconductor wafer from the process to the next process. The time used for transporting between the processes is usually a short time of about several minutes. Since the formation of the natural oxide film to be takes about 1 hour or more, since the natural oxide film does not have to be a problem in this conveyance period, conventionally, the inter-process conveyance has been performed in the state exposed to the atmosphere.

Certainly, the formation of the natural oxide film does not have to be a problem when the conveying system using the unmanned conveying vehicle is operating normally, but the failure of the semiconductor manufacturing apparatus, the conveying system, and the power failure due to power failure If the unmanned carrier does not operate according to the schedule due to the stop of the device or the failure of the conveyance path, the state in which the semiconductor wafer is left on the unmanned carrier is continued for a long time, which causes a problem of rapid growth of the above-described natural oxide film. .

The present invention has been made to solve this problem, and even when the transfer is unavoidable due to its own cause or due to loading, conveyance, etc. with a semiconductor wafer or the like, the generation of the natural oxide film is inevitable. An object of the present invention is to provide an unmanned conveying device capable of suppressing the problem.

In order to achieve the above object, the present invention provides an unmanned conveying apparatus that carries a conveyed object at a ground-side facility and goes to a destination by itself. The conveyed object is stored in a container and conveyed, and this container can supply a supply gas passage so as to replace the internal atmosphere. Provided is an unmanned conveying device for a clean room, characterized in that connected to the inert gas storage portion through.

In claim 2, the container made a structure with the ground side equipment, carrying a conveyed thing.

In Claim 3 and 4, it has a means of measuring a conveyance time, and when the conveyance time exceeds a preset value, it was set as the structure which replaces the internal atmosphere of a container with inert gas.

The gas supply passage of claim 5 is configured to close the supply gas passage when the oxygen concentration or the inert gas concentration in the container reaches a prescribed value after the supply gas passage is opened.

The supply gas passage has a single solenoid valve, and the solenoid valve is capable of supplying a small flow rate to the extent that the valve is opened after the gas replacement is completed in the gas replacement of the internal atmosphere. Screwed into the composition.

The supply gas passage has a small flow rate sending solenoid valve which is a main valve and a sub valve, and after the gas replacement is completed, the main valve is closed and the small flow rate is supplied by the sub valve.

In the present invention, when a semiconductor wafer or the like is stored in a container, air in the container is replaced with an inert gas, and the semiconductor wafer or the like is left in an inert gas atmosphere and conveyed.

EXAMPLE

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

1 and 2, reference numeral 1 denotes a wafer cassette containing the semiconductor wafer 2, and 10 and 20 denote semiconductor manufacturing apparatus.

The semiconductor manufacturing apparatus 10 (20) is arrange | positioned in a clean room at intervals to some extent.

30 is an unmanned transport vehicle which mounts the robot 31 for carrying on one end on the top plate 30B of the bogie body 30A, and the transfer box (30) on the other side of this top plate 30B. 40) is fixed.

32 is the drive wheel, 33 is the caster.

The conveying box 40 has a lid 42 attached to the box body 41 by a hinge, and has a cargo detecting sensor 43 therein.

The lid 42 is opened and closed by an opening and closing mechanism not shown, for example, an electric cylinder.

The gas inlet 44 and the exhaust port 45 are formed in the bottom wall of this conveyance box 40.

An inert gas container (in this example, a nitrogen gas container) 50 is provided in the bogie body 30A of the unmanned transport vehicle 30, and the spout and the transfer box 40 of the nitrogen gas container 50 are provided. The gas injection port 44 is connected to a pipe 52 through which the pressure reducing valve 51 and the supply gas valve 53 are interposed.

From the exhaust port 45 of the transfer box 40, an exhaust pipe 55 having an exhaust valve 54 extends through the ceiling plate 30B and into the bogie body 30A.

60 inputs a detection signal of the sensors described below as a controller, and simultaneously sends and receives a required timing signal between a main control device (not shown) that controls the unmanned vehicle 30 and the loading robot 31. In addition to outputting the open / close signals for the supply gas valve 53 and the exhaust valve 54, a signal for opening and closing the lid 42 of the transfer box 40 is output.

Next, the operation of this apparatus will be described.

Now, it is assumed that the wafer cassette 1 on the semiconductor manufacturing apparatus 20 is transferred to the semiconductor manufacturing apparatus 10.

When the unmanned vehicle 30 stops at a predetermined position in front of the semiconductor manufacturing apparatus 20, or reaches a position immediately before the predetermined position,

(1) Synchronizing with the timing signal output from the said main control device to the controller 60, the said electric cylinder of the conveyance box 40 extends | stretches and opens the lid 42. As shown in FIG.

When the lid 42 opens to a predetermined position, a lid open detection sensor (limit switch) (not shown) is operated.

When the vehicle stops at a predetermined position in front of the semiconductor manufacturing apparatus 20, the arm and wrist of the robot 31 for carrying out the transfer operation according to a predetermined program, provided that the lid open detection limit switch generates a detection signal. It starts.

(2) When the wafer cassette 1 is accommodated in the transfer box 40 in the semiconductor manufacturing apparatus 20 by the transfer operation of the transfer robot 31, the cargo detection sensor 43 outputs. The lid 42 is closed by the operation of the electric cylinder of the conveying box 40 to shrink.

When the lid 42 is closed, a lid closing detection sensor (limit switch) (not shown) operates.

(3) When the lid 42 is completely closed, i.e., when the lid closing detection limit switch outputs, a timer (not shown) in the controller 60 starts timing and at the same time the valve of the exhaust valve 54 opens. Then, the supply gas valve 53 is opened, and nitrogen gas is ejected from the nitrogen gas container 50 into the transfer box 40.

The air in the conveyance box 40 is pushed out by this nitrogen gas, and is exhausted from the exhaust port 45 into the bogie body 30A, and replaced by the nitrogen gas in the conveyance box 40.

The time T _k required for the gas replacement is set in the timer. When this timer times up, the exhaust valve 54 is closed, and then the supply gas valve 53 is closed.

(4) When the exhaust valve 54 and the supply gas valve 53 are closed, the unmanned transport vehicle 30 executes a traveling program directed to the semiconductor manufacturing apparatus 10 to start traveling toward the semiconductor manufacturing apparatus 10. .

(5) When the unmanned vehicle 30 stops at a predetermined position in front of the semiconductor manufacturing apparatus 10 or reaches a position immediately before the predetermined position, the main controller outputs the controller 60 to the controller 60. In synchronization with the timing signal, the electric cylinder of the transfer box 40 extends to open the lid 42, and when the unmanned vehicle 30 stops at a predetermined position in front of the semiconductor manufacturing apparatus 10, the robot for carrying Arm and wrist start the transfer operation according to a predetermined program, and the wafer cassette 1 in the transfer box 40 is transferred to the semiconductor manufacturing apparatus 10.

In this embodiment, the wafer cassette 1 containing the semiconductor wafer 2 is housed in the transfer box 40, and at a predetermined position in a state where the atmosphere in the transfer box 40 is an inert gas nitrogen gas atmosphere. Since the carrier is transported to a predetermined position, for example, even when the unmanned transport vehicle 30 is unavoidably stopped for a long time (sufficient time for the natural oxide film to grow) during transporting on the surface of the semiconductor wafer 2 for some reason. The growth of the natural oxide film can be suppressed.

3 shows another embodiment of the present invention, having a time circuit 70 and comparing the time T of the time circuit 70 with the set time To in the controller. When " To ", the controller 60 differs from that in Fig. 2 in that the controller 60 outputs " open " signals to the feed gas valve 53 and the exhaust valve 54.

The set time To is set to a value within a safe period without growth of the natural oxide film, for example, within 10 minutes.

Next, the operation of the present embodiment will be described.

Now, suppose that the wafer cassette 1 on the semiconductor manufacturing apparatus 20 is conveyed to the semiconductor manufacturing apparatus 10.

When the unmanned vehicle 30 stops at a predetermined position in front of the semiconductor manufacturing apparatus 20, or reaches a position immediately before the predetermined position,

(1) The electric cylinder of the transfer box 40 extends and opens the lid 42 in synchronization with the timing signal output from the main control device to the controller 60.

When the lid 42 is opened to a predetermined position, a lid open detection limit switch (not shown) is operated.

When the unmanned vehicle 30 stops at a predetermined position in front of the semiconductor manufacturing apparatus 20, the arm / wrist portion of the robot 31 for carrying on the condition that the lid open detection limit switch generates a detection signal is set to a predetermined position. The loading operation starts according to the program.

(2) When the wafer cassette 1 is accommodated in the transfer box 40 by the transfer operation of the transfer robot 31, the load detection sensor 43 outputs the time-receiving circuit 70 to time. Initiate recovery.

In addition, the lid 42 is closed by the electric cylinder of the transfer box 40 withering.

When the lid 42 is closed, the lid switch detecting limit switch is activated.

(3) When the lid 42 is completely closed, the unmanned transport vehicle 30 executes a traveling program to start traveling toward the semiconductor manufacturing apparatus 10.

(4) When the unmanned vehicle 30 stops at a predetermined position in front of the semiconductor manufacturing apparatus 10 or reaches a position ahead of the predetermined position, a timing signal output from the main controller to the controller 60. When the electric cylinder of the conveyance box 40 extends | moves in synchronism with the opening, the lid 42 is opened, and when the unmanned transportation vehicle 30 stops at the predetermined position in front of the semiconductor manufacturing apparatus 10, the robot 31 for a load is carried out. ), The arm and wrist portion starts the transfer operation according to a predetermined program, and the wafer cassette 1 in the transfer box 40 is transferred to the semiconductor manufacturing apparatus 10.

(5) When the unmanned transport vehicle 30 causes the stop for a long time as described above by the unmanned transport vehicle 30 due to some reason, the set time To has elapsed during this stop. The controller 60 outputs a command signal for opening the valve with respect to the supply gas valve 53 and the exhaust valve 54, and the timer starts timing.

As a result, the supply gas valve 53 opens the exhaust valve 54, and nitrogen gas is ejected from the nitrogen gas container 50 into the transfer box 40.

The air in the transfer box 40 is pushed out by this nitrogen gas, is exhausted from the exhaust port 45 into the constitution body 30A, and replaced with nitrogen gas in the transfer box 44.

When the timer times up, the exhaust valve 54 is closed, and then the supply gas valve 53 is closed.

In the present embodiment, the semiconductor wafer 2 is conveyed to the atmosphere atmosphere in the transport box 40 during the safe period (To) in which the growth of the natural oxide film is not observed, but the transport box 40 is passed after this period elapses. Since the inside is replaced with nitrogen gas, there are advantages as described below compared with those in FIG.

In the case where the distance between the semiconductor manufacturing apparatuses 10 and 20 is short and the required transport time during normal driving of the unmanned transport vehicle 30 is a short time, for example, several minutes, there is no fear that the natural oxide film grows rapidly at this short time. In the case of the embodiment of FIG. 2, the nitrogen gas is consumed in vain, and the nitrogen gas is exhausted into the atmosphere at the end of one conveying process, which may reduce the oxygen concentration in the narrow clean room while the conveying is repeated. In the example, the wasteful consumption of nitrogen gas can be prevented by replacing the inside of the transportation box 40 with nitrogen gas until the impeded transport process is completed only when normal operation of the unmanned transport vehicle 30 is impeded. In addition, there is no fear of lowering the oxygen concentration in the clean room.

In the above embodiment, after replacing the inside of the transfer box 40 with nitrogen gas, the supply gas valve 53 and the exhaust valve 54 are closed to stop the supply of nitrogen gas to the transfer box 40. After the gas valve 53 is not merely an open / close valve, but an electronic control valve that can control the opening degree of the valve, the exhaust valve 53 is removed and the inside of the transfer box 40 is replaced with nitrogen gas. The opening degree of the valve may be tightened to continuously send a small amount of nitrogen gas into the transport box 40 so that a nitrogen gas flow from the gas inlet 44 of the transport box 40 toward the exhaust port 54 is formed.

In addition, in the above embodiment, nitrogen gas was supplied from one supply gas valve 53. After the gas replacement is completed by installing a sub-valve (electromagnetic valve) for small flow rate delivery in addition to the supply gas valve 53, The supply gas valve 53 which is a main valve may be closed, and a minute flow may be supplied by the said sub valve.

In addition, in the embodiment of FIG. 2, after the replacement of the nitrogen gas in the transport box 40 is completed, the unmanned transport vehicle 30 starts to run. The nitrogen gas replacement is performed while the unmanned transport vehicle 30 is driven. You may do so.

In addition, in the above embodiment, the air in the transfer box 40 is pushed out by nitrogen gas to be replaced. However, a vacuum pump is installed to suck the air in the transfer box 40 as a vacuum pump, and then the nitrogen gas is transferred. It may be sent into the box 40.

Moreover, the supply time of nitrogen gas is prescribed | regulated by the timer (not shown) in the controller 60, The density | concentration meter which measures the oxygen concentration or nitrogen concentration in the conveyance box 40 is provided, and the supply gas valve 53 and the exhaust valve ( 54) may be closed.

In addition, the transport box 40 may have a structure in which a part of the ceiling plate 30B of the balance body 30A is placed on the floor and covered thereon.

In addition, although the transfer box 40 of each said Example is being fixed to the trolley | bogie body 30A, the transfer box 40 is not fixed to the trolley | bogie body 30A, and the transfer box 40 itself is a semiconductor manufacturing apparatus ( 10) may be exchanged with (20) side.

In each of the above embodiments, the robot 31 for transporting mounted on the unmanned vehicle 30 is used to exchange the conveyances with the ground side (semiconductor manufacturing apparatuses 10 and 20). It may be installed in the place, and the conveyance of the conveyance may be performed.

As described above, the organic oxide film grows during the conveying period because the semiconductor wafer or the like is stored and conveyed in the conveyance storage container connected to the inert gas container through the valve so that the internal atmosphere can be replaced. Since it can prevent that, the yield of semiconductor manufacturing can be improved compared with the past, and it is extremely effective to use for the manufacturing line of semiconductor with high integration degree.

Claims (7)

In the unmanned conveying apparatus used for conveying a semiconductor wafer and a board | substrate for electronic materials which carry a conveyed object from a ground-side installation and drive to a destination itself, the conveyed object is accommodated in a container and conveyed, and the trolley | bogie of the said unmanned carrier 30 The gas inlet 44 communicating with the pipe 52 via the inert gas container 50 loaded in the body 30A, the pressure reducing valve 51 and the supply gas valve 53 is the bottom wall of the transfer box 40. An exhaust port 45 formed on one side and connected to an exhaust pipe 55 communicating with the bogie body 30A with an exhaust valve 54 is formed on the other side of the bottom wall of the transfer box 40, and is output. When the lid 42 of the transfer box 40 is opened in synchronism with the timing signal and the lid 42 is closed by the output of the cargo detection sensor 43, the exhaust valve 54 after a predetermined time stored in the timekeeping circuit 70 has passed. ) Opens, followed by the feed gas valve (53). After the predetermined time has elapsed, the exhaust valve 54 and the supply gas valve 53 are sequentially closed, and the controller 60 controls the opening and closing of the lid 42 in synchronization with the timing signal output again. Unmanned transfer device for clean room. 2. The unmanned conveyance apparatus for a clean room according to claim 1, wherein the container communicates with the ground-side equipment while the conveyed material is stored. The unmanned conveyance apparatus for clean rooms of Claim 1 which has a means for measuring a conveyance time, and when the conveyance time exceeds a predetermined value, the internal atmosphere of a container is replaced with an inert gas. The unmanned conveyance apparatus for clean rooms of Claim 2 which has a means of measuring a conveyance time, and when the conveyance time exceeds a preset value, the internal atmosphere of a container is replaced with inert gas. The unmanned conveyance apparatus for a clean room according to any one of claims 1 to 4, wherein the supply gas passage is closed when the oxygen concentration or the inert gas concentration in the container reaches a prescribed value after the supply gas passage is opened. The supply gas passage is closed or the supply gas passage has a solenoid valve when the oxygen concentration or the inert gas concentration in the container reaches a prescribed value after the supply gas passage is opened. After the replacement is completed, the opening degree of the valve is unmanned conveying device for a clean room, characterized in that the small flow rate is tightened to enable delivery. The method according to any one of claims 1 to 4, wherein after the supply gas passage is opened, if the oxygen concentration or the inert gas concentration in the vessel reaches a prescribed value, the supply gas passage is closed or the supply gas passage is the main valve and the sub valve. An unmanned conveying device for a clean room, characterized in that the main valve is closed after the gas replacement is completed by the solenoid valve for micro flow rate sending, and the micro valve is supplied by the sub valve.