JP3728201B2 - Substrate processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate processing apparatus that applies, for example, resist solution, exposure, and development to a substrate such as a semiconductor wafer or a glass substrate for a liquid crystal display.
[0002]
[Prior art]
In general, a semiconductor manufacturing apparatus encloses a transfer space for a semiconductor wafer including a processing unit (hereinafter referred to as a wafer) with a housing provided in a clean room, and carries a wafer cassette into a cassette loading / unloading portion provided in a part of the housing. The wafer is taken out from the wafer cassette and transferred to the processing unit for processing.
[0003]
Recently, since the operating cost of clean rooms is high, a sealed cassette (for example, FOUP (front opening unified pod), SMIF (standard mechanical interface), etc.) is used as a wafer cassette, and the casing is also sealed. By keeping only the atmosphere in which the room is placed at a high cleanliness, it is considered to reduce the cleanliness in the cleanroom and thus reduce the operation cost.
[0004]
Briefly describing the configuration of the apparatus when using a sealed cassette, the casing is sealed so as to be generally airtight, and the inside thereof has a cleaner air than the clean room by a fan filter unit on the ceiling. Is maintained as a down flow and maintained at a positive pressure by the wind pressure of the air, a high cleanliness is maintained. In such an apparatus, the wafer is transferred by the sealed cassette outside the casing, and when the wafer is transferred to the casing, the sealed cassette is mounted on the casing, The operation is performed with the door provided at the carry-in / out port open.
[0005]
[Problems to be solved by the invention]
However, when a sealed cassette is mounted in a housing, the cassette-side open / close unit and the wafer loading / unloading port of the housing are as close as possible. Instead, for example, an extremely small gap of about 0.5 mm is interposed. Therefore, when the door is opened during the delivery of the wafer, the pressure in the housing is reduced through the gap, and air with a low cleanness on the clean room side flows into the inside of the housing. For this reason, particles enter the wafer transfer space and the wafer is likely to be contaminated by the particles. Also, when a chemically amplified resist is used as the resist, the pattern shape may be deteriorated. In other words, chemically amplified resist generates acid from the photosensitizer upon exposure, and this acid diffuses by heat treatment and acts as a catalyst, decomposing the base resin, which is the main component of the resist, and changing the molecular structure into a developer. On the other hand, it is solubilized or insolubilized, dislikes the presence of an alkali that neutralizes this acid in the atmosphere, and a chemical filter for removing the alkali is used in the fan filter unit.
[0006]
However, when an alkali such as ethylenediamine used for the paint on the inner wall of the clean room comes into contact with the acid near the surface of the resist film without using this chemical filter, the catalytic reaction due to the acid is suppressed, and the pattern shape is degraded. In the case of using a chemically amplified resist, it is necessary to suppress as much as possible the entry of the amine into the housing.
[0007]
Furthermore, although the inside of the normal casing is pressurized as described above, the fan filter unit stops as well as other processing devices in the event of a power failure, so the atmosphere on the clean room side enters from a minute gap and the same problem occurs. .
[0008]
The present invention has been made based on such circumstances, and the purpose thereof is to keep the substrate transfer space partitioned by the housing at a positive pressure, and the air on the clean room side enters the transfer space. It is to provide a technology to suppress this. Another object of the present invention is to provide a technique capable of maintaining the positive pressure in the transfer space even during a power failure.
[0009]
[Means for Solving the Problems]
In the substrate processing apparatus according to the present invention, a sealed substrate cassette with a lid for storing a substrate in an airtight space is mounted on a wall portion of a housing that partitions and forms a transfer space installed in a clean room. In the substrate processing apparatus configured to open the lid of the cassette and the door on the side of the wall, take out the substrate from the substrate cassette by the transfer means in the transfer space, and deliver it to the processing unit.
Air supply means for taking in air from the clean room, cleaning it and supplying the transport space to a positive pressure ;
Exhaust means for exhausting air supplied from the air supply means from the transfer space;
An electric power supply to the air supply means, and an uninterruptible power supply unit that supplies electric power from an emergency power storage unit when the general power supply unit is stopped,
And a control unit that reduces the supply flow rate of air in the air supply unit when power supply from the general power supply unit is stopped compared to before .
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a plan view showing a pattern forming apparatus as an embodiment of a substrate processing apparatus according to the present invention, and FIG. 2 is an external perspective view. This pattern forming apparatus is configured such that a coating / developing apparatus 100 composed of a plurality of blocks (cassette station 11, processing section S1, interface section S2) connected via a shutter (not shown) is connected to an exposure apparatus 200. The coating / developing apparatus 100 has an airtight structure in which a transfer unit, a processing unit, and the like for transferring a wafer W as a substrate to be processed are provided in a casing forming an exterior body. However, the airtight structure here is not a vacuum vessel, but a structure that does not allow the atmosphere to easily flow in from the outside. The outside air (air in the clean room) does not flow.
[0016]
When sequentially explaining from the carry-in side of the wafer W, C in the figure is a closed-type cassette (hereinafter referred to as a cassette) that forms a sealed substrate cassette that holds and transports 12 wafers W in a shelf shape. Includes a plurality of mounting tables 12 on which the cassette C is mounted. An opening 11b is formed in a slightly recessed position on the wall surface 11a in front of the mounting table 12 when viewed from the mounting position of the cassette C, and an openable / closable door 13 is provided in the opening 11b. Although the details will be described later, the mounting table 12 is configured to advance along the rail 12a to a position where the front end of the cassette C enters the recess of the opening 11b when the cassette C is mounted. ing. A driving mechanism 14 (not shown) for driving the door portion 13 and a wafer W transfer means 15 are provided inside the cassette station 11.
[0017]
Here, the vicinity of the door portion 13 will be briefly described with reference to FIGS. 3 and 4. The placement position of the cassette C on the placement table 12 is such that a slight gap d of, for example, about 0.5 mm is interposed between the tip and the wall surface 11a as shown in FIG. 3 in order to suppress the occurrence of contamination due to contact. Is positioned. The main body C1 of the cassette C is hermetically sealed by the lid C2. However, as shown in FIG. 4, the key 13a provided on the door portion 13 is inserted into the hole C3 of the lid C2 of the cassette C so that the lock is not shown. The lid body C1 and the door portion 13 are fixed by pins, and the main body C1 and the lid body C2 are separated from each other when the door portion 13 is retracted and lowered by the action of the drive mechanism 14. The delivery means 15 takes out the wafer W from the opened main body C1 with the lid C1 removed, and delivers the taken wafer W to the processing section S1 provided on the back side of the cassette station 11 via the shutter G1. is there.
[0018]
Returning to FIG. 1 and FIG. 2 again, the main conveying means 16 is provided in the center of the processing section S1, and the reflection is prevented, for example, on the right side when viewed from the cassette station 11 so as to surround it. The film coating unit 17A, the resist coating unit 17B, and the developing unit 18 are arranged with shelf units U1, U2, and U3 in which heating / cooling units and the like are stacked in multiple stages on the left side, near side, and back side, respectively. In this example, the antireflection film coating unit 17A, the resist coating unit 17B, and the developing unit 18 are arranged in such a manner that the antireflection film coating unit 17A and the resist coating unit 17B are arranged in the lower stage, and two developing units 18 are stacked thereon. It is said that. In the shelf units U1, U2, and U3, in addition to the heating unit and the cooling unit, a wafer transfer unit and the like are assigned vertically. The main transfer means 16 is configured to be movable up and down, movable back and forth, and rotatable about the vertical axis, and has a role of transferring the wafer W between the shelf units U1, U2, U3, the coating unit 17 and the developing unit 18. . However, in FIG. 2, the main conveyance means 16 is not drawn for convenience.
[0019]
The processing unit S1 is connected to the exposure apparatus 200 via the interface unit S2. The interface unit S2 delivers the wafer W among the processing block S1, the exposure apparatus 200, and the buffer cassette C0 by the delivery means 19.
[0020]
Further, as shown in FIG. 2, a fan filter unit 2 (21, 22, 23) which is an air supply means for taking in external air into the apparatus is provided on the ceiling portion 20 of the coating and developing apparatus 100. Each is configured to clean and flow the air taken into the cassette station 11, the processing unit S1, and the interface unit S2. Further, these fan filter units 2 (21, 22, 23) have a function of keeping the inside of the coating and developing apparatus 100 at a positive pressure together with an exhaust means to be described later provided on the bottom of each block. The configuration of the portion related to this positive pressure control will be described below with reference to the longitudinal sectional view shown in FIG.
[0021]
Although omitted in FIGS. 1 and 2, the housing of each block in the coating and developing apparatus 100 is partitioned so as to be airtight via shutters G1 and G2, as shown in FIG. Further, it is assumed that a transfer port a for transferring the wafer W is formed in front of and behind the transfer units U20 and U30 forming one stage of the processing units U2 and U3. In other words, the conveyance space in the claims refers to the internal space of the coating and developing apparatus 100 from the opening 11b described above to the exposure apparatus 200 communicating with the shutters G1 and G2 and the transfer units U20 and U30. It represents.
[0022]
The fan filter unit 2 is configured such that a fan 2a that takes in outside air is sandwiched between a chemical filter 2b to which an acid component for removing an alkali component such as amine or ammonia is added and a cleaning filter 2c for removing particles. As shown in the figure, a downward flow is formed for each of the aforementioned blocks. Each fan filter unit 2 (21, 22, 23) has a control unit 3 (31, 32, 33) for controlling the rotational speed of the fan 2a, and an uninterruptible power supply (UPS) 4 (41, 42, 43). ) Is connected through.
[0023]
On the other hand, the exhaust fan 5 (51, 52, 53) is provided on the bottom surface of each block of the cassette station 11, the processing unit S1, and the interface unit S2 via a ventilation plate 50. For the exhaust fan 52, for example, the processing unit U1. (Not shown) is constituted by three exhaust fans arranged below U2 and U3 so that a downward flow can be formed in each processing unit U1, U2 and U3. Further, a pressure gauge 6 (61, 62, 63) serving as a pressure detection unit is provided in each block of the cassette station 11, the processing unit S1, and the interface unit S2, and these pressure gauges 6 (61, 62, 63) are provided. ) Is connected to a control unit 7 (71, 72, 73) for controlling the exhaust flow rate of the exhaust fan 5 (51, 52, 53) corresponding to the measured pressure value.
[0024]
Next, the operation of the above embodiment will be described. Since the main part of the present embodiment is the pressure control in the coating and developing apparatus 100, this point will be mainly described. In addition, although the same pressure control is performed in each block in the coating and developing apparatus 100, attention is paid to the cassette station 11 in which pressure fluctuation is likely to occur compared to other blocks, and FIG. The description will be given with reference to 6 (b) and 6 (c). FIG. 6A is a characteristic diagram showing the pressure change in the cassette station 11 over time, and FIGS. 6B and 6C are the exhaust flow rate of the exhaust means 51 and the blast flow rate in the fan filter unit 21. FIG. 7 is a characteristic diagram showing each of them over time as in FIG.
[0025]
First, the state of the cassette station 11 before the cassette C is carried in will be described. The cassette station 11 is airtightly closed by the door portion 13 and the shutter G1 and cleaned by the functions of the fan filter unit 21 and the exhaust means 51. Furthermore, the positive pressure state indicated by A1 in FIG. 6 (a) is maintained by making the air flow rate larger than the exhaust gas flow rate. Here, the positive pressure state is, for example, 0.2 mmPa in the cassette station 11 and 0.4 Pa in the processing unit S1.
[0026]
In such a state, for example, the cassette C carried in from the outside is placed on the mounting table 12, and then the door body 13 is mounted on the lid C 2 of the cassette C, and the cassette is performed as described above by the operation of the drive mechanism 14. Lid C2 is removed from C. In this way, the inside of the main body C1 of the cassette C communicates with the inside of the cassette station 11, and the wafer W can be taken out.
[0027]
When the main body C1 and the cassette station 11 communicate with each other, as described above, the gap d (see FIG. 4) is interposed between the two, so that the atmosphere inside the cassette station 11 flows out to the clean room side where the atmospheric pressure is low. As shown at time t1 in (a), the atmospheric pressure drops instantaneously. At this time, a pressure measurement value is transmitted from the pressure gauge 61 to the control unit 71 at any time. When the control unit 71 recognizes the pressure drop, the exhaust flow rate is determined so that the pressure recovers to the pressure A1 before the door 13 is opened. Then, a command is issued to the exhaust means 51. Accordingly, as shown in FIGS. 6 (b) and 6 (C), the exhaust flow rate is lowered while the air blowing flow rate is maintained, the pressure in the cassette station 11 rises and recovers to the positive pressure A1. To do. The state of the pressure change is schematically shown in the figure.
[0028]
By removing the cover C2 of the cassette C, the pressure in the cassette station 11 drops instantaneously, but since it is immediately restored to the original positive pressure state, the clean room atmosphere is prevented from flowing from the gap d. In this state, the wafer W starts to be taken out. When the transfer means 15 takes out the wafer W from the cassette C, the shutter G1 is opened, and the wafer W is transferred into the processing unit S1 via, for example, the transfer unit U20 and subjected to resist application, exposure, development, etc. Is then returned to the cassette C via the delivery means 15 again.
[0029]
When pattern formation has been completed for a predetermined number of wafers W in the cassette C, for example, the door 13 is lifted from the lower side of the cassette station 11 by the drive mechanism 14, and the lid C2 that has been housed together with the door 13 is removed. Fit to the main body C1. When the door 13 seals the opening 11b of the cassette station 11 in an airtight manner, the gap d does not affect the inside of the cassette station 11, so the exhaust flow rate is lowered as shown at time t2 in FIG. 6 (a). The pressure temporarily increases by an amount corresponding to this, but when the control unit 71 recognizes this increase in pressure, this time, as shown in FIG. 6 (b), control is performed to return the exhaust flow rate to a value before time t1. At this time, since the air flow rate in the fan filter unit 21 is still maintained, the pressure in the cassette station 11 decreases and converges to A1 again.
[0030]
Here, the pressure control at the time of a power failure in the cassette station 11 will be described. Since the power supply to the exhaust means 51 is stopped at the time of a power failure, the exhaust in the cassette station 11 is not performed as shown at time t3 in FIG. On the unit 21 side, the uninterruptible power supply unit 41 is switched from the general power supply unit to the emergency power storage unit, and the supply of power is continued. At this time, if the control unit 31 grasps the occurrence of a power failure, the control unit 31 issues a command to the fan filter unit 21 to reduce the air flow rate so that the pressure in the cassette station 11 is maintained at the pressure A1. State is maintained.
[0031]
As described above, according to the above-described embodiment, since the pressure change in the coating and developing apparatus 100 is monitored and controlled to maintain a constant positive pressure state according to the pressure change, for example, Even when the pressure generated when the wafer W is loaded, etc., it can be instantaneously restored to the positive pressure state, and the positive pressure state can be continuously maintained from loading of the wafer W to processing and unloading. Become. In particular, since contamination, amines, and the like on the clean room side are prevented from flowing into the processing unit S1 side through the cassette station 11, it occurs when opening the cassette C as described in “Problems to be Solved by the Invention”. Defects due to the gap d are less likely to occur.
[0032]
Further, since the uninterruptible power supply unit 4 (41, 42, 43) is provided in the fan filter unit 2 on the air blowing side, a positive pressure state can be maintained even during a power failure, and the exhaust means 5 (51, 52) during a power failure. , 53) in consideration of the interruption of the supply of electric power, there is an advantage that the inside of the coating and developing device 100 can be maintained at a constant pressure regardless of the presence or absence of a power failure.
[0033]
In the above-described embodiment, for example, the speed of the fan in the exhaust unit 51 is controlled in order to change the pressure in the cassette station 11, but the exhaust unit 51 is disposed above the fan 81 as shown in FIG. The flow rate adjusting means 82 may be provided in close contact, and the exhaust flow rate may be changed by driving the flow rate adjusting means 82 from the control unit 71. As shown in FIGS. 7 and 8, for example, the flow rate adjusting means 82 is supported by a common guide P on its side and arranged in the vertical direction with the same shape of the perforated plates 82a and 82b. It comprises a drive unit 83 that slides in the X direction from the side. When the drive unit 83 is driven by the command of the control unit 71 and the slide amount of the porous plate 82a is adjusted, the opening area of each vent hole Q is adjusted as shown in FIG. 8, and the air flow rate, that is, the exhaust flow rate changes. .
[0034]
Further, for example, when the pressure control in the cassette station 11 is performed, the control unit 71 controls the exhaust means 51 according to the pressure measurement value transmitted from the pressure gauge 61. The degree of pressure drop in the cassette station 11 when the part 11b opens can be grasped in advance, and the pressure in the cassette station 11 can be controlled to increase simultaneously with the opening to compensate for the pressure drop. Good.
[0035]
Furthermore, in the above-described embodiment, the case where the wafer W is taken out from one cassette C has been described as an example. However, as shown in FIG. 2, a plurality of openings 11b may be opened at the same time. Therefore, in such a case, the number of open openings 11b can be counted by the control unit 31, and the exhaust flow rate can be automatically changed according to the number.
[0036]
Furthermore, as shown in FIG. 9, the exhaust unit 5 (51, 52, 53) is not controlled by the control unit 7 (71, 72, 73), and the fan filter unit by the control unit 3 (31, 32, 33) is used. 2 (21, 22, 23) may be used to maintain the positive pressure. In this case, for example, in the cassette station 11, the pressure is changed by adjusting the flow rate of air flow by the fan 2a. If the flow rate is increased and conversely high, the air flow rate is decreased. Further, in the state of FIG. 9, the uninterruptible power supply 4 (41, 42, 43) may be connected to the corresponding exhaust means 5 (51, 52, 53) side, the fan filter unit 2 and the exhaust You may make it connect to both of the means 5. FIG.
[0037]
【The invention's effect】
As described above, according to the substrate processing apparatus of the present invention, it is possible to perform substrate processing in an environment that is not easily affected by contamination, and to prevent the substrate transfer space from being contaminated even during a power failure. Can do.
[Brief description of the drawings]
FIG. 1 is a plan view showing an appearance of a coating and developing apparatus used in an embodiment of the present invention.
FIG. 2 is a perspective view showing an external appearance of a coating and developing apparatus used in the embodiment of the present invention.
FIG. 3 is a longitudinal sectional view for explaining a portion relating to positive pressure maintenance in the coating and developing apparatus.
FIG. 4 is a schematic cross-sectional view illustrating the vicinity of a door portion of a cassette station.
FIG. 5 is a schematic cross-sectional view illustrating the vicinity of the door of the cassette station.
FIG. 6 is a characteristic diagram showing a pressure change in the cassette station. FIG. 7 is a schematic longitudinal sectional view showing another embodiment of the present invention.
FIG. 8 is a schematic view showing a flow rate adjusting means provided in the other embodiment.
FIG. 9 is a schematic longitudinal sectional view showing still another embodiment of the present invention.
[Explanation of symbols]
W Wafer C Closed-type cassette S1 Processing section S2 Interface section 11 Cassette station 12 Mounting table 13 Door section 2 Fan filter unit 3 Control unit 4 Uninterruptible power supply section 5 Exhaust means 6 Pressure gauge 7 Control unit

Claims (1)

A closed-type substrate cassette with a lid for storing the substrate in an airtight space is mounted on the wall portion of the casing that defines the transfer space installed in the clean room, and the lid of the substrate cassette and the wall side In the substrate processing apparatus configured to take out the substrate from the substrate cassette by the transfer means in the transfer space and deliver it to the processing unit.
Air supply means for taking in air from the clean room, cleaning it and supplying the transport space to a positive pressure;
Exhaust means for exhausting air supplied from the air supply means from the transfer space;
An electric power supply to the air supply means and an uninterruptible power supply unit that supplies electric power from an emergency power storage unit when the general power supply unit is stopped,
A substrate processing apparatus , comprising: a control unit that reduces an air supply flow rate in the air supply unit when power supply from the general power supply unit is stopped compared to before .

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