JP2004128456A - Drying treatment equipment and drying treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide drying treatment equipment and a drying treatment method capable of preventing a wet treated material from being dried without putting this material in a vessel to dip it in a solvent in storing the material in a supercritical drying device and reducing the amount of the solvent. <P>SOLUTION: In drying treatment equipment that is provided with at least one supercritical drying device storing the wet treated material inside to perform supercritical drying, and the material is conveyed to the supercritical drying device in such a state that the wet treated material is wet by a solvent that is used for the wet treatment. There is provided a vapor pressure adjusting device reducing the amount of evaporation of this solvent to avoid the solvent evaporation that causes the material to be dried, while the material is conveyed to the supercritical drying device after the wet treatment. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a drying treatment facility for storing a wet-processed material in a supercritical drying apparatus without drying the material and thereafter performing supercritical drying, and a drying treatment method therefor.
[0002]
[Prior art]
Conventionally, in the manufacturing process of manufacturing semiconductor devices, materials such as wafers have been used, and the wafers are transported to a supercritical drying apparatus through wet processing such as etching, film formation, and development. Supercritical drying is being performed.
Generally, as a supercritical drying apparatus and a supercritical drying method for supercritically drying a wafer or the like, a supercritical drying apparatus and a method as disclosed in JP-A-2002-33302 are adopted.
[0003]
In this supercritical drying apparatus, this wafer is stored in a supercritical drying apparatus while being immersed in a solvent in a small container in order to prevent resist destruction or microstructural destruction of the wet-processed wafer. Supercritical drying is performed by a supercritical drying device.
When the wafer is dried by a supercritical drying apparatus, the supercritical drying is performed while the wafer is placed in a plurality of small containers and immersed in a solvent.
[0004]
[Problems to be solved by the invention]
However, in the conventional supercritical drying apparatus disclosed in JP-A-2002-33302, since the wafer is immersed in the solvent, the wafer is dried before the wet-processed wafer is stored in the supercritical drying apparatus. It is effective in this respect without destroying the resist or destroying the fine structure. However, since each wafer is immersed in a solvent in a small container, the number of wafers (quantity) is reduced. When the amount is increased, the amount of the solvent becomes large as a result.
[0005]
Also, during supercritical drying, since the supercritical drying is performed in a state where the wafer is immersed in a solvent in a plurality of small containers, the amount of solvent to be dried increases, and the drying time becomes longer. there were.
Accordingly, the present invention has been made in view of the above-described problems, and when storing a wet-processed material in a supercritical drying apparatus, it is possible to prevent the material from drying without putting the material in a container and immersing the material in a solvent. It is an object of the present invention to provide a drying treatment facility and a drying treatment method capable of reducing the amount of drying.
[0006]
[Means for Solving the Problems]
The present invention employs the following solution in order to achieve the above object. That is, the apparatus includes at least one supercritical drying device that stores therein the wet-processed material and performs supercritical drying, and the wet-processed material is wetted by the solvent used in the wet process. In the drying processing equipment transported to the critical drying device, while the material is transported to the supercritical drying device, so that the solvent does not evaporate and the material is not dried, a vapor pressure adjusting device that reduces the amount of evaporation of the solvent is provided. It is characterized by being provided.
[0007]
According to the present invention, since the vapor pressure adjusting device for reducing the amount of evaporation of the solvent is provided, it is not necessary to put the material in a container and immerse the solvent in the supercritical drying device as in the related art. In addition, it is possible to reduce the amount of the solvent by an amount that does not allow the material to be put in the container and soaked in the solvent.
Further, since the evaporation amount of the solvent can be reduced, it is possible to prevent the resist from being destroyed in the material or the fine structure from being destroyed.
Further, it is preferable that the vapor pressure adjusting device is a device that makes a vapor pressure of a solvent contained in an atmosphere surrounding the material close to a saturated vapor pressure.
[0008]
According to this, since the vapor pressure of the solvent contained in the atmosphere surrounding the material becomes the saturated vapor pressure, the solvent is less likely to evaporate under the atmosphere surrounding the material, and as a result, the amount of evaporation of the solvent can be suppressed. .
Further, it is preferable that the vapor pressure adjusting device is a humidifying device that increases the humidity of an atmosphere surrounding the material.
According to this, since the water vapor pressure of the atmosphere surrounding the material becomes close to the saturated vapor pressure, when the solvent used in the wet processing is an aqueous solution, the solvent is less likely to evaporate, so that the evaporation of the solvent is reduced. be able to.
[0009]
In addition, the material wetted with the solvent used in the wet processing is stored in the supercritical drying apparatus, and a liquid having the same composition as the solvent remaining in the material is mixed with the fluid used in the supercritical drying. It is preferable that the mixed fluid is supplied into a supercritical drying apparatus, the pressure in the supercritical drying apparatus is increased, and then the supercritical drying is performed.
According to this, since the liquid having the same composition as the solvent is supplied in the pressurizing process of increasing the pressure of the supercritical drying apparatus, it is possible to prevent or reduce the drying of the solvent remaining in the material.
[0010]
Further, in the pressure increasing process of increasing the pressure of the supercritical drying device, a liquid having the same composition as the solvent left in the material and a fluid used in the supercritical drying are simultaneously supplied into the supercritical drying device, After increasing the pressure in the supercritical drying apparatus, supercritical drying may be performed.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a drying treatment facility and a drying treatment method according to the present invention will be described with reference to the drawings.
The drying processing equipment 1 is used, for example, in a manufacturing process of a wafer or the like which is a material of a semiconductor device.
As shown in FIG. 1, the drying processing equipment 1 is disposed in a clean room, and stores a wet-processed wafer therein and performs supercritical drying. A transport device 3 for transporting to the critical drying device 2 and a vapor pressure adjusting device 4 are provided.
[0012]
The drying processing equipment 1 is housed in a housing 5 arranged in a clean room, and a wet processing device 6 for performing wet processing on a wafer and a cassette station 7 are provided in the housing 5. The cassette station 7 is partitioned by a partition 5A. As the wet processing apparatus 6, various liquid processing apparatuses such as a developing machine, an etching apparatus, a cleaning apparatus, a coater, a gelling apparatus, and a rinsing apparatus are employed. Therefore, the solvent used for the wet processing differs depending on the type of the wet processing apparatus 6, so that the wafer that has been subjected to the wet processing is wet by the solvent according to the form of the wet processing apparatus.
[0013]
The steam pressure adjusting device 4 is adjacent to the inside of the housing 5 and is a device that adjusts the steam pressure in the housing 5 to near the saturated steam pressure, or adjusts the steam pressure in the housing 5 to be constant. .
Although an example in which cassettes 7a, 7b, and 7c can be placed in the cassette station 7 is shown, one to four cassettes are usually handled by the transport device 3 as needed. I have.
As shown in FIG. 1, the transport device 3 has a first hand 8 and a second hand 9, wherein the first hand 8 is for wet transport and the second hand 9 is for dry transport. The first hand 8 is used when the wafer is wet, that is, in the example of FIG. 1, the wafer is transferred from the wet processing apparatus 6 to the supercritical drying apparatus 2. The second hand 9 is used when the wafer is in a dry state, that is, in the example of FIG. 1, between the cassette station 7 and the wet processing apparatus 6 and from the supercritical drying apparatus 2 to the cassette station 7. This makes it possible to stably return the wafer in a dry state after the completion of the supercritical drying to the cassette station 7 without any risk of contamination by moisture.
[0014]
Each of the first hand 8 and the second hand 9 shown in FIG. 1 has an arm which can be turned (turned) around a vertical axis, and this arm can be extended and contracted, and the wafer support at the tip of the arm can be swung. Although it is possible to configure the scalar type transfer robot described above, it is needless to say that the present invention is not limited to this configuration. Further, the transport device 3 may be a single hand (transport body), but preferably has two or more hands.
Next, a description will be given of a process in which the wafer in the cassette station 7 is wet-processed by the wet processing device 6 and then transferred to the supercritical drying device 2 and a method of not drying the wafer in the transfer process.
[0015]
First, the transfer device 3 takes out a wafer to be processed placed in the cassette station 7 and transfers it to the wet processing device 6.
When the wet processing apparatus 6 is a developing machine, development is performed by dropping an alkaline aqueous solution on the wafer surface. Usually, the time required for development is about 45 seconds to 1 minute. After developing with a developer for a predetermined time, pure water rinsing is performed. The time required for the rinsing step is about the same as that for development. When the wet processing apparatus 6 is a developing machine, the wafer is transferred to the drying processing apparatus 2 after the pure water rinsing step, and the pure water rinse composed of pure water is used as the solvent of the present invention. Equivalent to.
[0016]
The wafer after the rinsing step is in a state of being wet with a pure water rinsing liquid (solvent). In this state, the wafer is taken out of the wet processing apparatus 6 by the transfer device 3 and transferred to the supercritical drying device 2. Conveyed. While the wafer is transferred from the wet processing apparatus 6 to the supercritical drying apparatus 2, the wafer is exposed to the atmosphere surrounding the wafer (the atmosphere in the housing 5). In the present invention, since the wafer is naturally dried and the microstructure portion of the wafer may collapse due to the capillary force, the transfer from the wet processing apparatus 6 to the supercritical drying apparatus 2 is performed promptly and the transfer process is performed. The solvent of the wafer is prevented from spilling due to vibration, tilt, acceleration during operation or stop, and the like.
[0017]
On the other hand, when the wafer is exposed to the atmosphere in the housing 5 when the inside of the housing 5 is maintained at a room temperature of 22 ° C. and a humidity of about 40%, pure water as a solvent remaining on the wafer becomes pure water. Dry by about 0.4 μm thickness in 10 seconds by natural convection of air on the water surface. When ventilation or the like is performed in the housing 5 and forced convection occurs, the thickness of drying further increases. In the case of a resist having a pattern dimension of 0.1 μm or less and an aspect ratio defined by height and width of about 3, the solvent existing between the patterns on the wafer is completely dried. In the present invention, while the wafer is transferred from the wet processing apparatus 6 to the supercritical drying apparatus 2, the solvent left on the wafer by the vapor pressure adjusting device 4 is prevented from evaporating and drying.
[0018]
This vapor pressure adjusting device 4 is a device that makes the vapor pressure of the solvent contained in the housing 5 close to the saturated vapor pressure. When the solvent is pure water or an aqueous solution, a humidifying device that increases the humidity in the housing 5 is used as the vapor pressure adjusting device 4.
That is, in the above embodiment, since the solvent is composed of pure water, the inside of the housing 5 is humidified by the humidifying device (the vapor pressure adjusting device 4), and the humidity in the housing 5 is increased (the housing 5 The internal water vapor pressure rises).
Thus, while the wafer is transferred from the wet processing apparatus 6 to the supercritical drying apparatus 2, the solvent is less likely to evaporate even if the wafer is exposed to the atmosphere in the housing 5, the evaporation amount is reduced, and the wafer does not dry. .
[0019]
Therefore, it is possible to prevent the wafer from drying even if the wet-processed wafer is not put in a container and immersed in the solvent. Further, since the vapor pressure of the solvent contained in the housing 5 can be adjusted to be constant near the saturated vapor pressure by the vapor pressure adjusting device 4, the wafer does not dry under this atmosphere.
The vapor pressure adjusting device 4 may be adjacent to the housing 5 or may be installed in the housing 5 or as a common device of the plurality of housings 5.
Further, the appropriate humidity of the atmosphere surrounding the wafer in the housing 5 depends on the time during which the wafer or the like is in contact with the atmosphere during transfer, but by maintaining at least 70% or more, preferably 80% or more, Natural drying of a wafer of 0.1 μm or less can be reduced or prevented, and the wafer can be transported without breaking.
[0020]
Further, when the atmosphere in the housing 5 is put into the supercritical drying device 2 and the vapor pressure of the solvent in the supercritical drying device 2 is indirectly brought close to the saturated vapor pressure by the vapor pressure adjusting device 4, It is effective.
In the above-described embodiment, the vapor pressure of the solvent contained in the entire atmosphere of the housing 5 including the wet processing apparatus 6 and the supercritical drying apparatus 2 is increased to near the saturated vapor pressure. Although an example has been described, the vapor pressure of the solvent may be increased to near the saturated vapor pressure only in the atmosphere where the wafer is installed or transported. For example, as shown in FIG. 2, a transfer route 10 in which a wafer is transferred from the wet processing apparatus 6 to the supercritical drying apparatus 2 is partitioned by the housing 5B, and is included in the atmosphere in the partitioned housing 5B. It is preferable that the vapor pressure of the solvent be increased to near the saturated vapor pressure by the vapor pressure adjusting device 4. With this configuration, since the volume inside the housing 5B is smaller than that of the housing 5, it is possible to reduce the amount of the solvent necessary for setting the vapor pressure of the solvent in the housing 5B to the saturated vapor pressure. In FIG. 2, the cassette station 7 is omitted, and the wet-processed wafer is moved from the wet processing apparatus 6 to the supercritical drying apparatus 2 in the housing 5B. Is adjacent to the housing 5B.
[0021]
Next, a method of drying the wafer transported in a state of being wet by the supercritical drying device 2 by the supercritical drying device 2 will be described. In the supercritical drying device 2, a supercritical fluid is used, and a carbon dioxide fluid is usually used as the supercritical fluid.
As shown in FIG. 3, this supercritical fluid is a fluid in which the temperature and the pressure (critical point) of the gas and the liquid are beyond the limit and the capillary force is substantially zero.
In order to supercritically dry a wafer with the supercritical drying apparatus 2, the pressure inside the supercritical drying apparatus 2 is increased with carbon dioxide while the wafer is housed in the supercritical drying apparatus 2. 2 must be under supercritical drying conditions (for example, 50 ° C., 10 MPa), but before the inside of the supercritical drying device 2 becomes the supercritical drying condition (the pressurizing process of increasing the pressure inside the supercritical drying device 2), the pressure is increased. Since there is an interface between the carbon dioxide fluid and the solvent on the wafer, this solvent dissolves in the carbon dioxide and dries the wafer, causing resist destruction of the wafer or destruction of the microstructure. There is a risk of doing. In particular, at low pressure (about 3 to 4 MPa), the solubility of the solvent in carbon dioxide is often high, so that if the pressure is increased, drying takes place and the risk of resist collapse is great.
[0022]
Therefore, in the present invention, in the pressurizing step of pressurizing the inside of the supercritical drying apparatus 2, the same fluid as the carbon dioxide gas or the carbon dioxide liquid used in the pressurizing step and the solvent remaining on the wafer after the wet processing are used. The pressure inside the supercritical drying apparatus 2 is increased by using a liquid mixture of a composition or a gas mixed with a gas until the inside of the supercritical drying apparatus 2 reaches a supercritical drying condition. With this configuration, in the pressure increasing process, the rate of dissolution in the mixed fluid of the solvent is reduced, and the amount of the dissolved solvent in the mixed fluid is reduced, so that the drying of the wafer can be prevented or reduced. Note that, in this case, a carbon dioxide gas used in the pressure increasing process, or a fluid such as a carbon dioxide liquid, and a liquid or a gas having the same composition as the solvent remaining on the wafer after the wet processing are supercritical. You may make it supply simultaneously in the drying device 2.
[0023]
If the inside of the supercritical drying apparatus 2 is set to the supercritical drying condition by the above-described method, the solvent and the supercritical carbon dioxide between the resist patterns on the wafer are in a single-phase state, and there is no gas-liquid interface. The resist does not collapse on the wafer or the fine structure is not destroyed by the tension or the like. Thereafter, if the pressure is reduced to change from the supercritical state to the gas state, the wafer can be dried without interfacial tension without crossing the gas-liquid balance line.
In the case of simultaneous supply of carbon dioxide and a solvent, it is also possible to stop the liquid supply before the supercritical processing conditions are reached and to increase the pressure only with carbon dioxide.
[0024]
Further, as a method for preventing the solvent of the wafer from drying in the pressure increasing process, it is also possible to increase the pressure only with carbon dioxide while dropping the solvent on the wafer surface. In this case, unless the solvent is supplied in an amount greater than the amount that dissolves in carbon dioxide, the wafer will dry. Therefore, the amount of the solvent will increase, the load on drying after the end of the pressure increase will increase, and the processing time will increase. For this reason, it is most efficient to increase the pressure using carbon dioxide in which the solvent is sufficiently dissolved in carbon dioxide (carbon dioxide in a state where the solubility of the solvent in carbon dioxide is a saturated solubility).
[0025]
In FIG. 1, a stationary (rotating) transport device is illustrated as the transport device 3, but a mobile (traveling) transport device 3 may be used depending on the situation. Further, the second transfer device 3 may be arranged in association with the cassette station 7 in FIG. In this case, the second transfer device controls the transfer of the wafer from the cassette and transfers the wafer to and from the first transfer device.
Further, the wet processing apparatus 3 for performing wet processing on a wafer may be integrated with the drying processing equipment 1.
[0026]
Although the embodiment of the present invention is as described above, various modifications are possible within the scope of the gist.
In FIG. 1, the wet processing apparatus 6 and the supercritical drying apparatus 2 are each shown as a single unit, but it is a matter of course to arrange a plurality of wet processing apparatuses 6 and the supercritical drying apparatus 2 as necessary. is there. Further, in addition to the wet processing apparatus 6 and the supercritical drying apparatus 2, a baking furnace or a replacement apparatus may be incorporated.
Further, in the above embodiment, the wafer that has been wet-processed is transported by the transport device 3, but the drying processing equipment 1 does not necessarily need to have a transport device that transports the wafer. . For example, a wafer that has been wet-processed may be conveyed artificially and transferred to the supercritical drying apparatus 2 in a state where the wafer is wetted by the solvent used in the wet process.
[0027]
Further, in the above-described embodiment, the solvent of the wafer wetted by the wet processing is a pure water rinsing liquid composed of pure water, but the present invention is not limited to this, and the solvent may be appropriately determined depending on the type of the wet processing apparatus. Be changed. For example, the solvent may be water, a fluorocarbon-based solution such as hydrofluoroether or Fluorinert (registered trademark, 3M), an alcohol-based solution such as telomer alcohol, or another organic solvent.
When an organic solvent (for example, a fluorocarbon-based solution) is used as the solvent and the wafer is wet with the organic solvent, the inside of the casings 5 and 5B is saturated with a saturated vapor pressure using vapor generated by evaporating the same liquid as the organic solvent. It should be close to. When evaporating the organic solvent to obtain its vapor, the vapor pressure adjusting device 4 heats and evaporates the organic solvent, or a vapor pressure generating device that applies ultrasonic waves to the organic solvent to evaporate it. May be used.
[0028]
【The invention's effect】
According to the present invention, the vapor pressure of the solvent contained in the atmosphere surrounding the wet-processed wafer is brought close to the saturated vapor pressure by the vapor pressure adjusting device, and the wafer is transported or processed under this atmosphere. It is possible to prevent the resist destruction of the wafer or the destruction of the fine structure, and to reduce the amount of the solvent.
[Brief description of the drawings]
FIG. 1 is a layout view in which a drying processing facility according to an embodiment of the present invention is disposed in a manufacturing facility for a wafer to be a semiconductor material.
FIG. 2 is a layout view showing a form in which a transfer route of the wafer is divided by a housing.
FIG. 3 is a state diagram of pressure and temperature.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 Drying processing equipment 2 Supercritical drying device 3 Transport device 4 Vapor pressure adjusting device 5 Housing 6 Wet processing device 7 Cassette station 8 First hand 9 Second hand

Claims (10)

It is provided with at least one supercritical drying device (2) for storing the wet-processed material therein and performing supercritical drying, wherein the wet-processed material is wetted by the solvent used in the wet process, In the drying processing equipment transported to the supercritical drying device (2),
A vapor pressure adjusting device (4) for reducing the amount of evaporation of the solvent so that the solvent does not evaporate and the material is not dried while the material is wet-processed and then conveyed to a supercritical drying device (2). A drying treatment facility, characterized in that: The drying treatment equipment according to claim 1, wherein the vapor pressure adjusting device (4) is a device that adjusts a vapor pressure of a solvent contained in an atmosphere surrounding the material to a constant state. The drying treatment equipment according to claim 1, wherein the vapor pressure adjusting device (4) is a device for setting a vapor pressure of a solvent contained in an atmosphere surrounding the material to near a saturated vapor pressure. The drying treatment equipment according to claim 1, wherein the vapor pressure adjusting device (4) is a humidifying device for increasing the humidity of an atmosphere surrounding the material. Solvent left in the material by transporting or processing the material wetted with the solvent used in the wet processing under an atmosphere in which the vapor pressure of the solvent used in the wet processing is close to the saturated vapor pressure, or A drying process, wherein the drying process is not performed. The drying method according to claim 5, wherein the solvent comprises pure water or water. A drying method, comprising: transporting or processing a material wetted with a solvent in a state where the humidity of an atmosphere surrounding the material is set to 70% or more, so that a solvent remaining in the material is not dried. The material wetted with the solvent used in the wet processing is stored in the supercritical drying device (2), and a liquid having the same composition as the solvent remaining in the material and a fluid used in the supercritical drying are mixed. A drying method comprising supplying a mixed fluid into a supercritical drying device (2), increasing the pressure in the supercritical drying device (2), and then performing supercritical drying. The material wetted with the solvent used in the wet processing is stored in the supercritical drying apparatus (2), and a liquid having the same composition as the solvent remaining in the material and a fluid used in the supercritical drying are superposed. A drying treatment method comprising simultaneously supplying the mixture into a critical drying device (2) to increase the pressure in the supercritical drying device (2), and then performing supercritical drying. The drying method according to claim 5, wherein the solvent is a fluorocarbon-based solution or an alcohol-based solution.

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