JPH10321698A - Substrate treatment method and its equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate smoothly opening the lid body of a substrate cassette, when the inside of a closed type substrate cassette wherein a substrate accommodating space has an atmospheric pressure is opened in a carrying-in chamber in a positive pressure atmosphere, by turning the inside of the carrying-in chamber into a positive pressure atmosphere of inert gas, by reopening supply of the inert gas. SOLUTION: The inside of a cassette 3 is maintained in the state of an atmospheric pressure or nearly equal to the state. when a cassette 3 is set on a cassette mounting part 4, a signal A1 is outputted to a controller C. On the basis of the signal A1, a shutting command signal B1 is outputted to an on-off valve V1, and supply of nitrogen gas to a loading area S2 is stopped. A door 60 and a lid body 32 are opened to a lid body open-shut part 6. When the supply of nitrogen gas is stopped, the pressure in the loading area S2 decreases down to about atmospheric pressure. In the lid body open-shut part 6, the lid body 32 is removed, and a signal A2 is outputted to the controller C. As a result, an opening command signal B3 is outputted to the on-off valve V1, and the supply of nitrogen gas to the loading area S2 is again performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a substrate processing method and apparatus.

[0002]

2. Description of the Related Art One of the manufacturing processes of a semiconductor wafer (hereinafter, referred to as a wafer) includes a heat treatment such as a film forming process and an oxide film formation. Such a heat treatment is performed by, for example, a heat treatment apparatus shown in FIG. I have. This heat treatment apparatus includes a work area S1 in which an operator or an automatic transfer robot carries the cassette 1, and a roll having a higher degree of cleanness than the work area S1.
And a loading area S2. The loading area S2 is partitioned by a wall portion 11, and a heat treatment furnace described later is provided in the loading area S2.

In such an apparatus, for example, the loading area S2 is purged with nitrogen (N ₂ ) gas in order to prevent the formation of a natural oxide film and the entrapment of air into the heat treatment furnace. It is set to a positive pressure than the work area S1,
Clean air in the loading area S2 is applied to the work area S1.
To prevent particles from entering the working area S1 into the loading area S2. For this reason, a constant amount of nitrogen gas is always supplied to the loading area S2 in order to keep the nitrogen concentration in the area constant, whereby the pressure in the area is, for example, 1 Pa or more with respect to the atmospheric pressure. , Preferably 100P
The pressure is adjusted to be about a positive pressure.

[0004] In order to suppress particle contamination of a semiconductor wafer (hereinafter, referred to as a wafer), a closed wafer cassette (hereinafter, referred to as a close type cassette) has been studied (Monthly Semiconductor Semiconductor World).
This close type cassette is a cassette body 10 for accommodating, for example, 13 wafers W.
And a lid 10a for hermetically closing a wafer take-out opening formed in the cassette body 10.

When this close type cassette is applied to the above-described heat treatment apparatus, the close type cassette 1 is mounted on a mounting table 12 provided on the work area S1 side, and Is mounted from the side of the work area S1 into the opening 11a formed at the bottom. Here, the opening 11a is always the door 13
The cover 10a is opened by the opening / closing means 14 provided on the door portion 13. The removed lid body 10a is carried together with the door portion 13 into the loading area S2 by the door opening / closing mechanism 15 for moving the door portion 13 up and down and moving in the horizontal direction, and thereafter the loading area S2.
The wafer W in the close type cassette 1 is taken out by the transfer means 16 which can be moved up and down, advance and retreat, and rotate freely from the side, and is transferred to the wafer boat 17. Next, the wafer boat 17 is carried into the heat treatment furnace 18 where a predetermined heat treatment is performed.

[0006]

The inside of the close cassette 1 is purged with, for example, nitrogen gas, but the pressure in the cassette 1 is set at about 1 atm (atmospheric pressure). . Therefore, since the pressure in the close cassette 1 is slightly smaller than the loading area S2,
When the close cassette 10 is mounted on the opening 11a of the wall 11 and the lid 10a is to be opened, it is difficult to open the lid 10a due to the pressure difference between the two, and the lid 10a is removed together with the door 13. Large power for driving the door opening and closing mechanism 15
Is required.

As described above, the close type cassette 1
When there is a pressure difference between the inside and the loading area S2, when the lid 10a is opened, the gas suddenly drops.
As a result, particles may be generated.

The present invention has been made under such circumstances, and an object of the present invention is to open a sealed substrate cassette in which a substrate accommodating space is at or near atmospheric pressure into a loading chamber in a positive pressure atmosphere. In this regard, it is an object of the present invention to provide a substrate processing method and apparatus capable of smoothly opening a lid of a substrate cassette.

[0009]

For this reason, the substrate processing method of the present invention provides a method for transferring a substrate from a substrate cassette in which a substrate accommodating space is at atmospheric pressure or almost atmospheric pressure and which is always closed, into a carry-in chamber of an inert gas atmosphere. In the method of loading and thereafter processing the substrate, a step of supplying an inert gas into the loading chamber to make the loading chamber a positive pressure atmosphere by the inert gas, and a step immediately before opening the lid of the substrate cassette. Stopping the supply of the inert gas, then opening the lid of the substrate cassette to open the substrate housing space into the loading chamber, and then restarting the supply of the inert gas to disconnect the loading chamber. Producing a positive pressure atmosphere with an active gas.

In the substrate processing apparatus of the present invention, a carry-in chamber of an inert gas atmosphere interposed between an atmospheric pressure atmosphere and a substrate processing section, and a substrate accommodating space at atmospheric pressure or almost atmospheric pressure, are always sealed. And a substrate cassette formed on the wall of the loading chamber, which is normally closed and opened when the substrate cassette is mounted from the atmospheric pressure side to move the substrate accommodation space in the substrate cassette into the loading chamber. A loading / unloading port for transferring the substrate to the loading chamber, wherein the loading chamber takes out the substrate from the substrate cassette and processes the substrate in the substrate processing unit. An opening / closing valve for opening / closing the active gas supply path, a detection unit for detecting that the substrate cassette is at a predetermined position before the lid of the substrate cassette is opened, Outputs a closing command signal of the on-off valve on the basis of a detection signal from the detection unit, characterized by comprising control means for outputting an open command signal of the on-off valve after the substrate cassette is opened, the. Here, the control means is configured to output an opening command signal for the on-off valve based on a signal output when the lid opening / closing section for opening / closing the lid of the substrate cassette opens the lid. May be.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where the substrate processing apparatus of the present invention is applied to a vertical heat treatment apparatus will be described. FIG. 1 is a cross-sectional view showing one embodiment of a vertical heat treatment apparatus, and FIG. 2 is a perspective view showing a main part thereof. First, the overall configuration of the vertical heat treatment apparatus will be briefly described. This apparatus is divided by a wall 21 into a working area S1 in an atmospheric pressure atmosphere and a loading area S2 forming a loading chamber. The wall 21 has an opening 2 serving as a carry-in port for transferring a substrate, for example, a wafer W.
1a is formed, and the working area S of the opening 21a is formed.
On one side, a closed type cassette 3 (hereinafter, referred to as a cassette 3) as a closed type substrate cassette is mounted.

The cassette 3 will be described with reference to FIGS. 3 and 4. For example, the cassette 3 has 13 wafers W.
The cassette body 31 has a wafer holding unit 30 formed in multiple stages so as to hold the wafer in a shelf shape, and a lid 32 for hermetically closing an opening 33 which is a wafer take-out port of the cassette body 31. . The cover 32 has, for example, two key holes 34 formed therein. A key 35 provided in a key operation mechanism to be described later is inserted into the key hole 34 and turned, whereby an upper end of the cover 32 is formed. A lock pin (not shown) protrudes from the lower end and the lower end, and the lid 32 is fixed to the cassette main body 31. In the bottom of the cassette 3, for example, concave portions 36 are formed at three positions.

The cassette 3 is mounted on a stage 41 of a cassette mounting portion 4 provided below the opening 21a of the work area S1. 3 is held at a position suitable for the opening 21a. The stage 41 is supported by a stage support 42, and the stage support 42 can be moved in the mounting / removing direction by a guide rail 43 provided on a base 44 in the mounting / removing direction of the cassette 3. It is configured as follows.

On the upper surface of the stage 41, for example, three projections 41 are provided at positions corresponding to the concave portions 36 of the cassette 3.
a is provided in the recess 36 of the cassette 3.
a is engaged so that the position of the cassette 3 on the stage 41 is adjusted. Also, stage 41
Is provided with a switch 5 serving as a detection unit.
The switch 5 is provided, for example, when a pin 51 projecting from the stage 41 and constantly suppressed upward is pressed from above against the restraining force, the control means (control).
B) It is configured to output a signal to C. In FIG. 1, reference numeral 40 denotes a stocker 40 that accommodates a plurality of cassettes 3 arranged vertically.

The loading area S of the opening 21a
On the second side, a door portion 60 for a wall portion for airtightly closing the opening 21a is provided. This door portion 60 has an opening 2
1 a is formed so as to cover the periphery thereof, and is configured to be opened and closed by a door opening and closing mechanism 61. The door opening / closing mechanism 61 includes a lifting base 62 for moving the door unit 60 up and down by a lifting shaft 62a, and a horizontal base 63 for moving the lifting base 62 in the horizontal direction.

The door section 60 is provided with a key operating mechanism 64 for opening and closing the lid 32 of the cassette 3 for moving the key 35 forward and backward and rotating the key. The door opening / closing mechanism 6 and the key operating mechanism 64 for opening / closing the door section 60 and the lid 32 constitute a lid opening / closing section 6, and the lid opening / closing section 6 is driven by the controller C. It is configured to be controlled and recognizes that the lid 32 has been opened,
The recognized signal is output to the controller C.

At the back of the loading area S2, there is provided a heat treatment furnace 71 serving as a substrate processing section for performing a heat treatment on the wafer. Below the heat treatment furnace 71, for example, 150 wafers are provided. Holding the wafer W in a shelf shape,
A wafer boat 72 for carrying the heat treatment furnace 71 by the elevator 73 is provided. The cassette 3 is located immediately behind the opening 21a of the loading area S2.
A transfer mechanism 8 for transferring wafers between the wafer boat 72 and the wafer boat 72 is provided. The transfer mechanism 8 can transfer a plurality of wafers, for example, five wafers at a time, and one by one. For example, five transfer arms 81 are provided so that the transfer can be performed, and the transfer arm 81 is configured to be able to move forward and backward, move up and down, and rotate freely.

Also, on the side wall of the loading area S2,
For example, a gas supply pipe 22 serving as an inert gas supply path is provided so as to open between the heat treatment furnace 71 and the wafer boat 72 when the wafer W is at the transfer position of the wafer W. A supply source of an inert gas (not shown) such as a nitrogen gas is connected to the other end. The gas supply pipe 22 is provided with an on-off valve (on-off valve) V1 configured to be opened and closed by the controller C, and the control of stopping and starting the supply of nitrogen gas to the loading area S2 is performed. It is controlled by the laser C. Furthermore,
An exhaust pipe 23 is connected to the lower side of the side wall of the loading area S2, and the other end of the exhaust pipe 23 is open to the factory exhaust which is open to the atmosphere.

Next, a substrate processing method performed by the above apparatus will be described with reference to FIGS. After the wafers W are stored in the cassette 3, the cassette 3 is purged with, for example, nitrogen gas, and the inside of the cassette 3 is maintained at or substantially at atmospheric pressure. On the other hand, a constant amount of nitrogen gas is constantly supplied through the gas supply pipe 22 while exhausting the loading area S2 through the exhaust pipe 23. For example, the pressure becomes 1 Pa or more, preferably about 100 Pa, higher than the atmospheric pressure. (Step S1 in FIG. 7).

First, as shown in FIG. 5 (a), the cassette 3 is transferred to the projection 41a on the stage 41 of the cassette mounting portion 4 by the automatic transfer robot (not shown) and the concave portion 3 of the cassette 3.
6, the projection 41a is placed so as to engage with the recess 36 (step S2). Then, the stage support 42 is pressed by a pressing mechanism (not shown), and the cassette 3 is mounted on the opening 21a at the opening. At this time, switch 5
Then, when the cassette 3 is mounted on the cassette mounting portion 4,
As shown in FIG. 5B, the pin 51 is
Is turned on by being pressed by the bottom surface of the controller C, and outputs a signal A1 to the controller C (see FIG. 6).

In the controller C, based on the signal A1, the closing command signal B1 is supplied to the normally open / closed valve V1.
Is output, whereby the opening / closing valve V1 is closed, and the supply of nitrogen gas to the loading area S2 is stopped (step S3). After a predetermined time, for example, 20 to 30 seconds, has elapsed since the supply of the nitrogen gas was stopped, the controller B outputs a signal B2 to the lid opening / closing section 6 so as to open the door 60 and the lid 32. (Step S4).

When the supply of nitrogen gas is stopped,
The pressure in the loading area S2 gradually decreases due to the factory exhaust that is opened to the atmosphere, and after 20 to 30 seconds from the stop of the supply, the pressure is reduced to approximately the atmospheric pressure. Even if the supply of the nitrogen gas is stopped for 20 to 30 seconds, the exhaust pipe 23 is sufficiently long, so that there is no fear that the outside air flows backward.

In the lid opening / closing section 6, based on the signal B2, the key 35 of the key operating mechanism 65 of the lid opening / closing means 63 is inserted into the keyhole 34 of the lid 32 and turned, thereby releasing the lock pin. I do. And the horizontal base 63 of the door opening / closing mechanism 61
Then, the door unit 60 is moved backward, and then lowered by the elevating base 62 to remove the lid 32 together with the door unit 60 from the opening 21a.

At this time, when the lid 32 is removed from the lid opening / closing section 6, a signal A2 is output to the controller C. The controller C outputs an open command signal B3 to the closed on-off valve V1 based on the signal A2, thereby opening the on-off valve V1 and restarting the supply of nitrogen gas to the loading area S2. (Step S5).

On the other hand, in the loading area S2, the transfer arm 81 of the transfer mechanism 8 is advanced into the cassette 3, and the five wafers W of the cassette 3 are collectively picked up and held.
The wafer is transferred to the wafer boat 72. Thus, the wafer boat 7
After transferring, for example, 150 wafers W to the wafer 2, the wafer boat 72 is raised by the boat elevator 73 and loaded into the heat treatment furnace 71, and the wafer W is subjected to a predetermined heat treatment.

In such a substrate processing method, the supply of the nitrogen gas to the loading area S2 is stopped, and the pressure in the area S2 is set to approximately the atmospheric pressure so that the difference between the loading area S2 and the cassette 3 is reduced. After the pressure has been removed or is significantly reduced, the lid 32 is opened. For this reason, the lid 32 can be smoothly opened with almost no external pressing force, and the driving force of the lid opening / closing portion 6 for removing the lid 32 can be reduced. In addition, when the lid 32 is opened, the gas is prevented from suddenly flowing into the cassette 3, and the generation of particles is prevented.

In the above-described embodiment, the lid 32 is opened in anticipation that the pressure in the loading area S2 will decrease after a lapse of 20 to 30 seconds after the opening and closing valve V1 is closed. The pressure in S2 is detected, and when this pressure falls to a predetermined value, the door
0 and a signal for opening the lid 32 may be output. Further, the detection of the position of the cassette 3 is not limited to the configuration for detecting that the cassette 3 is mounted on the cassette mounting portion 4. For example, an automatic transport robot for transporting the cassette into the work area S1 separates the cassette 3. It may be configured to detect that the operation is performed.

Further, a time T from when the supply of the nitrogen gas is stopped to when the pressure is reduced to the atmospheric pressure is obtained in advance, and in the process of transporting the cassette by the automatic transport robot, the time T before the time when the lid of the cassette is opened is removed. The corresponding transfer point may be detected on software and a signal may be sent to the control system.
Can be omitted from the time of waiting until the cover 32 is opened after the cover is mounted on the wall 21, so that the throughput can be improved.

Further, in the above embodiment, the lid opening / closing section 6
The controller C outputs an opening command signal for the opening / closing valve V1 based on a signal output when the lid 32 is opened, but a timer is started when the position of the cassette 3 is detected. Then, the time is up after a lapse of time from the closing of the opening / closing valve V1 to the opening of the lid 32 of the cassette 3, and the opening / closing valve V1 may be opened based on a signal output at the time. .

In the above-described embodiment, the loading area S2 is connected to the factory exhaust which is open to the atmosphere via the exhaust pipe 23, but the other end of the exhaust pipe 23 is connected to the exhaust pump. In addition to the connection, an exhaust valve may be provided in the exhaust pipe 23. In such a configuration, when the supply of the nitrogen gas is stopped, the pressure in the loading area S2 is gradually reduced due to the exhaust by the exhaust pump, and 20 to 30 minutes after the supply of the nitrogen gas is stopped.
After a lapse of seconds, the pressure is reduced to almost the atmospheric pressure. At this time, since the exhaust power of the exhaust pump is small, the loading area S
There is almost no negative pressure in 2 and there is no problem in processing.

[0031]

According to the present invention, when a closed substrate cassette whose substrate accommodation space is at or near atmospheric pressure is opened into a loading chamber in a positive pressure atmosphere, the lid of the substrate cassette is smoothly opened. Can be opened.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a substrate processing apparatus according to the present invention.

FIG. 2 is a perspective view showing a main part of an embodiment of the substrate processing apparatus of the present invention.

FIG. 3 is a closed type substrate cassette (closed type cassette).
FIG.

FIG. 4 is a cross-sectional view showing a close cassette.

FIG. 5 is a side view for explaining a state in which a close type cassette is mounted on a cassette mounting portion.

FIG. 6 is a cross-sectional view for explaining one embodiment of the substrate processing method of the present invention.

FIG. 7 is a flowchart for explaining one embodiment of the substrate processing method of the present invention.

FIG. 8 is a sectional view showing a conventional vertical heat treatment apparatus using a close type cassette.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Wall part 21a Opening 22 Gas supply pipe 3 Closed cassette 4 Cassette mounting part 5 Switch 6 Lid opening / closing part 60 Door part C Controller S1 Working area S2 Loading area V1 Opening / closing valve

Claims (3)

[Claims] 1. A method of carrying a substrate into a carry-in chamber in an inert gas atmosphere from a substrate cassette which is always closed and has a substrate accommodation space at or substantially at atmospheric pressure, and thereafter processes the substrate. A step of supplying an inert gas into the loading chamber to make the loading chamber a positive pressure atmosphere by the inert gas; and a step of stopping the supply of the inert gas shortly before opening the lid of the substrate cassette. Next, a step of opening the lid of the substrate cassette to open the substrate accommodating space into the loading chamber, and a step of resuming the supply of the inert gas to bring the loading chamber into a positive pressure atmosphere by the inert gas. A substrate processing method comprising: 2. A loading chamber for an inert gas atmosphere interposed between an atmospheric pressure atmosphere and a substrate processing section, and a substrate cassette in which a substrate accommodating space is at or near atmospheric pressure and is always sealed. A substrate transfer formed on a wall of the loading chamber, which is normally closed and opened when the substrate cassette is mounted from the atmospheric pressure atmosphere side to open a substrate accommodation space in the substrate cassette into the loading chamber. A loading port, and a substrate processing apparatus that takes out a substrate from the substrate cassette in the loading chamber and processes the substrate in the substrate processing unit, wherein an inert gas supply path that supplies an inert gas to the loading chamber is provided. An on-off valve for opening and closing; a detection unit for detecting that the substrate cassette is at a predetermined position before the lid of the substrate cassette is opened; and a detection from the detection unit. Control means for outputting a closing command signal for the on-off valve based on the signal and outputting an opening command signal for the on-off valve after the substrate cassette is opened. 3. The control means outputs an opening command signal for the on / off valve based on a signal output when a lid opening / closing section for opening / closing the lid of the substrate cassette opens the lid. 3. The substrate processing apparatus according to claim 2, wherein: