JP2008300736A - Vaporizing device for drying liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vaporizing device for drying liquid by which vaporization of drying liquid is simply achieved with a compact configuration while suppressing generation of fine mist. <P>SOLUTION: The vaporizing device 1 for vaporizing an IPA12 used for drying a to-be-dried object includes a storage tank 10 for storing the IPA12, a vaporization vessel 20 having a space for vaporizing the IPA12, and a liquid-raising body 30 which connects the inside of the storage tank 10 to the inside of the vaporization vessel 20 and sucks up the IPA12 in the storage tank 10 by capillary phenomenon to supply it to the inside of the vaporization vessel 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vaporizer that vaporizes a drying liquid used to dry a wet-cleaned substrate, for example, in semiconductor manufacturing or liquid crystal manufacturing.

  In semiconductor manufacturing and liquid crystal manufacturing, a cleaning operation is a very important operation that greatly affects quality and yield. As a cleaning method, there is dry cleaning, but wet cleaning is often used from the viewpoint of production efficiency. In wet cleaning, particles, metals, organic substances, etc. are decomposed and removed with various chemicals, and the chemicals remaining on the substrate are cleaned with ultrapure water. After this cleaning, the substrate is dried in order to completely remove moisture on the substrate such as a wafer or glass.

  In the drying process, it is very important to prevent the reattachment of impurities and to reduce the generation of watermarks. As a drying method that is widely used at present, there are Marangoni drying and Rotagoni drying using IPA (isopropyl alcohol) vapor. For example, in the cleaning / drying method of Patent Document 1, the IPA vapor is blown through the nozzle to the gas-liquid interface for pulling up the wafer, thereby removing the pure water by the Marangoni flow and replacing the pure water remaining in the recess with IPA. Promote and dry the wafer.

In the drying of the substrate using such IPA vapor, it is necessary to vaporize the IPA solution. In the vaporizer of Patent Document 1, the IPA solution is heated in the storage tank and the carrier gas is bubbled, so that the IPA Was vaporizing.
JP-A-10-118586

  However, in the conventional vaporizer described above, since the IPA solution is bubbled by the carrier gas, not only IPA vapor but also fine mist of IPA is generated. The generated fine mist becomes a coarser mist when blown out from the nozzle. Therefore, the replacement with the pure water remaining in the miniaturized pattern does not proceed, and there is a possibility that a drying defect may occur. In order to prevent this, it is conceivable to provide a heater in front of the nozzle in order to vaporize the generated fine mist. However, providing a separate heater complicates the apparatus.

  Further, in the above conventional vaporizer, when the IPA solution is to be replenished, the temperature of the IPA solution in the storage tank fluctuates and the vapor pressure fluctuates, so that the amount of IPA vapor supplied becomes unstable, resulting in poor drying. There was also a risk of occurrence. In order to prevent this, it is conceivable to increase the size of the IPA storage tank, but the overall size of the apparatus increases due to the increase in the size of the storage tank.

  The present invention has been made in view of the above-described circumstances, and provides a drying liquid vaporization apparatus capable of realizing vaporization of a drying liquid while suppressing generation of fine mist with a simple and compact configuration. The purpose is to do.

  A drying liquid vaporizing apparatus according to the present invention is a vaporizing apparatus for vaporizing a drying liquid used for drying a drying object, and has a storage tank for storing the drying liquid and a space for vaporizing the drying liquid. A vaporizing container is connected to the inside of the storage tank and the inside of the vaporizing container, and the pumped liquid sucks up the drying liquid in the storage tank by capillary action and supplies it to the vaporizing container.

  In this vaporizer, since the liquid for drying is sucked up by the pumping liquid using the capillary phenomenon and supplied into the vaporization container, the ratio of the gas-liquid interface per unit surface area is increased by the amount of the material constituting the liquid. Get smaller. Further, bubbling of the drying liquid can be eliminated. Therefore, the evaporation rate of the drying liquid per unit surface area is reduced, and as a result, generation of fine mist accompanying evaporation of the drying liquid can be suppressed. Moreover, since it is not necessary to provide a heater for vaporizing the fine mist, the apparatus can be simplified. Furthermore, it is not necessary to enlarge the storage tank in order to suppress temperature fluctuations during replenishment of the drying liquid, and the apparatus can be made compact.

  The vaporizer may include a communication line that communicates the space in the vaporization container and the space in the storage tank. If it does in this way, the space in a vaporization container and the space in a storage tank can be maintained at the same pressure, and the suction of the drying liquid using the capillary phenomenon by a pumping liquid becomes easy.

  The vaporizer may include a vaporization heater that is provided in the vaporization container and heats the drying liquid sucked up by the pumped liquid. In this way, it becomes easy to adjust the vapor amount by adjusting the vapor pressure of the drying liquid.

  The vaporizer may include a carrier gas supply line that supplies a carrier gas into the vaporization container, and a gas heater that is provided on the carrier gas supply line and heats the carrier gas. In this way, it is possible to suppress the fluctuation of the vapor amount of the drying liquid by adjusting the temperature of the carrier gas.

  ADVANTAGE OF THE INVENTION According to this invention, the vaporization apparatus of the drying liquid which can implement | achieve vaporization of the drying liquid which suppressed generation | occurrence | production of fine mist with a simple and compact structure can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a diagram showing a configuration of a drying liquid vaporizer according to the present embodiment. As shown in FIG. 1, the vaporizer 1 includes a storage tank 10, a vaporization container 20, a pumped liquid 30, a communication line 40, a vaporization heater 50, a carrier gas supply line 60, and a gas heater 70.

  The storage tank 10 is a sealed container and stores the drying liquid 12 therein. As the drying liquid 12, an organic solvent such as IPA (isopropyl alcohol), MA (methyl alcohol), or EA (ethyl alcohol) that dissolves in water, has a lower boiling point than water, and a smaller surface tension or latent heat of evaporation than water is used. Can do. In this embodiment, the IPA 12 will be described.

  The vaporization container 20 is a sealed container and has a space for vaporizing the IPA 12 therein. From the bottom wall of the vaporization container 20, a cylindrical communication pipe 22 extending into the storage tank 10 extends and communicates with both. The lower end of the communication pipe 22 is immersed in the IPA 12 stored in the storage tank 10. The vaporization container 20 is covered with a heat insulating material (not shown).

  The pumped liquid 30 is filled in the communication pipe 22 and connects the storage tank 10 and the vaporization container 20. More specifically, the lower end of the pumped liquid 30 reaches the lower end of the communication pipe 22, and the upper end extends at the bottom of the vaporization container 20. The pumped liquid 30 sucks up the IPA 12 in the storage tank 10 by capillary action and supplies it to the vaporization container 20. The pumped liquid 30 is configured by bundling fiber bodies such as glass wool, glass fiber, and quartz wool. The size of the fibrous body at this time is not particularly limited, and for example, a fiber having a diameter of several μm to several tens of μm can be suitably used.

  The communication line 40 is for maintaining the inside of the vaporization container 20 and the storage tank 10 at the same pressure, and communicates the upper space in the vaporization container 20 and the upper space in the storage tank 10. The communication line 40 is covered with a heat insulating material 42.

  The vaporizing heater 50 heats the IPA 12 sucked up by the pumped liquid 30. The vaporizing heater 50 is arranged in an outer peripheral surface at the bottom of the vaporizing container 20. The IPA 12 is heated to a desired temperature (for example, 70 to 80 ° C.) by the heater 50 for vaporization, so that the vapor pressure of the IPA 12 is adjusted. The vaporizing heater 50 is controlled by a temperature controller 52 based on the detected temperature of the pumped liquid 30.

The carrier gas supply line 60 supplies a carrier gas into the vaporization container 20. As the carrier gas, an inert gas such as N ₂ gas (nitrogen gas) or argon gas can be used. In this embodiment, N ₂ gas will be described. The carrier gas supply line 60 is provided with a flow rate adjusting device 62, and the N ₂ gas whose flow rate has been adjusted is supplied into the vaporization vessel 20 and mixed with the IPA vapor, and this mixed gas is pumped through the transfer line 80. Is done.

The gas heater 70 is provided in the middle of the carrier gas supply line 60 and heats the N ₂ gas. The gas heater 70 adjusts the temperature of the N ₂ gas to a temperature slightly higher than the vaporization temperature of the IPA 12. The temperature difference is preferably a temperature difference that does not recondense IPA vapor in the vaporization vessel 20, and is, for example, about 1 to 5 ° C. By adjusting the temperature in this way, fluctuations in the amount of steam of the IPA 12 can be suppressed. The gas heater 70 is controlled by a temperature controller 72 based on the detected temperature of the N ₂ gas.

From the upper wall of the vaporization vessel 20, a transfer line 80 that communicates the vaporization vessel 20 with the nozzle 100 that ejects IPA vapor extends. An auxiliary line 90 that supplies N ₂ gas is connected to the middle of the transfer line 80. A flow rate adjusting device 92 is provided on the auxiliary line 90, and the N ₂ gas whose flow rate has been adjusted is supplied into the transfer line 80, thereby assisting the transfer of the mixed gas. The conveyance line 80 is covered with a heat insulating material 82.

  Next, the operation and effect of the above-described vaporizer 1 will be described.

  In the vaporizer 1, first, the IPA 12 is stored in the storage tank 10. At the time of storage, the storage amount is adjusted so that a space is created in the upper part and the lower end of the pumped liquid 30 is immersed in the IPA 12.

  When the pumped liquid 30 is immersed in the IPA 12, the IPA 12 is sucked up through the gap between the fibers by capillary action, and the IPA 12 reaches the vaporization container 20. At this time, since the inside of the vaporization container 20 and the inside of the storage tank 10 are maintained at the same pressure by the communication line 40, the IPA 12 can be sucked up easily. The IPA 12 reaching the vaporization container 20 is heated to a desired temperature by the vaporization heater 50 and vaporized, and IPA vapor is generated.

On the other hand, N ₂ gas is supplied into the vaporization vessel 20 through the carrier gas supply line 60. Upon supplying the N ₂ gas, to heat the _{N 2} gas by gas heater 70 to a temperature slightly higher than the vaporization temperature of IPA12.

The N ₂ gas supplied into the vaporization vessel 20 is mixed with the IPA vapor in the vaporization vessel 20 and is pumped from the transfer line 80 toward the nozzle 100. At this time, N ₂ gas is also supplied from the auxiliary line 90 to assist the conveyance of the mixed gas. The pressure of the mixed gas is preferably about 0.2 to 0.5 MPa, for example. Then, when the mixed gas is injected from the nozzle 100, the IPA vapor is adiabatically expanded and cooled to become a fine mist of the IPA liquid, and the gas liquid for pulling up the substrate (drying target) such as a wafer or liquid crystal glass. Supplied to the interface. As a result, removal of pure water remaining on the substrate during cleaning and replacement of pure water remaining in the concave portions of the fine pattern with IPA are promoted, and the substrate is dried.

  As described above in detail, since the vaporizer 1 of the present embodiment sucks up the IPA 12 by using the capillary phenomenon with the pumped liquid 30 and supplies the IPA 12 into the vaporizer container 20, as shown in FIG. The proportion of the gas-liquid interface per unit surface area is reduced by the amount occupied by the substances constituting 30. Further, bubbling of the IPA 12 can be eliminated. Therefore, the evaporation rate of the IPA 12 per unit surface area is reduced, and as a result, generation of fine mist accompanying the evaporation of the IPA 12 can be suppressed.

  In addition, since it is not necessary to provide a heater for vaporizing the fine mist of the IPA 12 on the transfer line 80, the apparatus can be simplified.

  Furthermore, it is not necessary to enlarge the storage tank 10 in order to suppress temperature fluctuations during the replenishment of the IPA 12, and the vaporization container 20 can be made small, so that the apparatus can be made compact. In addition, by reducing the vaporization container 20 in this way, the amount of IPA consumed unnecessarily can be reduced.

  Moreover, since the communication line 40 which connects the space in the vaporization container 20 and the space in the storage tank 10 is provided, the space in the vaporization container 20 and the space in the storage tank 10 can be maintained at the same pressure. The IPA 12 can be easily sucked using the capillary phenomenon due to the above.

Further, since the IPA 12 sucked up by the pumped liquid 30 can be heated by the vaporizing heater 50, the vapor pressure of the IPA 12 can be adjusted to easily adjust the amount of vapor. That is, the IPA concentration supplied to the nozzle 100 can be easily adjusted by the N ₂ gas amount adjusted by the flow rate adjusting device 62 and the temperature control by the temperature controller 72, and the vaporizing heater 50 is controlled by this temperature controller 72. By controlling this, the vapor pressure of the IPA 12 can be adjusted to easily adjust the amount of vapor.

Further, a gas heater 70 for heating the N ₂ gas is provided on the carrier gas supply line 60, and the N ₂ gas can be heated to a temperature slightly higher than the IPA vaporization temperature. By preventing the recondensation of the IPA vapor, fluctuations in the vapor amount of the IPA 12 can be suppressed.

  Moreover, since the vaporization container 20 and the conveyance line 80 are covered with the heat insulating material 82, it is possible to prevent the mist obtained by recondensing the IPA vapor from being pumped to the nozzle 100. Further, since the communication pipe 40 is covered with the heat insulating material 42, it is possible to prevent the IPA vapor from recondensing and returning to the storage tank 10.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the above-described embodiment, the fibrous body has been described as the substance constituting the pumped liquid 30, but it is formed from a material having a lyophilic surface, and is dried using a capillary phenomenon by adjusting the diameter and packing density. The lifted liquid 30 may be made of any material that can suck up the liquid 12 for use. For example, the pumping liquid 30 may be formed from a bundle of thin tubes, or the pumping liquid is formed from a substance having a continuous gap as a flow path for the drying liquid 12 to rise, such as a string, a sponge, sand, a porous body, or a cloth. 30 may be configured.

  However, in drying a substrate in semiconductor manufacturing or liquid crystal manufacturing, it is preferable that the pumped liquid 30 is made of a glass-based material such as glass wool, glass fiber, or quartz wool because it does not contain metal impurities.

It is a figure which shows the structure of the vaporization apparatus of the drying liquid which concerns on embodiment. It is a figure which shows the state by which IPA was sucked up by the lifting liquid by capillary action.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vaporizer, 10 ... Storage tank, 12 ... IPA (drying liquid), 20 ... Vaporization container, 30 ... Lifting liquid, 40 ... Communication line, 50 ... Vaporization heater, 60 ... Carrier gas supply line, 70 ... Gas Heater.

Claims (4)

A vaporizer for vaporizing a drying liquid used for drying an object to be dried,
A storage tank for storing the drying liquid;
A vaporization container having a space for vaporizing the drying liquid;
A pumped liquid that connects the inside of the storage tank and the inside of the vaporization container, sucks up the drying liquid in the storage tank by capillary action, and supplies the liquid into the vaporization container;
An apparatus for vaporizing a drying liquid, comprising:   2. The drying liquid vaporizer according to claim 1, further comprising a communication line communicating the space in the vaporization container and the space in the storage tank.   3. The drying liquid vaporization apparatus according to claim 1, further comprising a vaporization heater that is provided in the vaporization container and heats the drying liquid sucked up by the pumped liquid. 4. A carrier gas supply line for supplying a carrier gas into the vaporization vessel;
A gas heater provided on the carrier gas supply line for heating the carrier gas;
The vaporizing device for a drying liquid according to claim 1, comprising:

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