JPH06216105A - Paper drying device - Google Patents

Abstract

PURPOSE:To achieve a positive drying treatment by providing a purification bath incorporating an ultrasonic vibrator and a return pipe system for refluxing the purification treatment liquid inside the purification bath to a vapor bath. CONSTITUTION:A treatment liquid (IPA liquid) 3 with a large amount of water content which is condensed on the surface of a wafer 7, drop, and stay at a pan 14 is flown to a purification bath 30 and at the same time an IPA liquid 3 with increased wafer content at the bottom of a vapor bath 1 is allowed to flow to the purification bath 30. Then, ultrasonic vibration is applied to the IPA liquid 3 within the purification bath 30 by an ultrasonic vibrator 31 for promoting vaporization of water content due to cavitation and then a steam 37 is delivered outside the bath 30 from a steam delivery port 33. Also, since the water content is several % to 1% and a purification IPA liquid 39 is refluxed from the system of a return pipe 34 to the paper bath 1, the IPA liquid 3 staying at the bottom of the vapor bath 1 constantly has low water content and generates a large amount of IPA liquid steam 6, thus performing a positive drying treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor drying apparatus, and more particularly to a technique for performing vapor drying while controlling the water content of a vaporized treatment liquid, and is applied to, for example, drying semiconductor thin plates (wafers) in the production of semiconductor devices. And about effective technology.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, a wafer is repeatedly subjected to photolithography. Then, the cleaning / drying process of the wafer is performed each time. One of the wafer drying processes is vapor drying. The vapor drying is described in, for example, “solid state tecnology (Japanese version) Japanese edition”, published by Nippon SST Co., Ltd., April 1991, April 15, the same day, P21. In this document, regarding vapor drying, "Wafer drying is performed by single-wafer, in-line, vapor drying. IPA (or other solvent) is self-taining to obtain a process temperature by an external heating mechanism. The wafer should be positioned with the J-arm and vaporized to dry. "

[Electronic Materials] 199 issued by the Industrial Research Board
July 2nd issue, issued July 1st of the same year, P38-P42,
A liquid crystal panel cleaning device is described. In this document, ultrasonic cleaning and high frequency cleaning are described in "40
Ultrasonic cleaning, which removes dust adhering to the surface of the object to be cleaned by the physical action of cavitation generated by applying strong ultrasonic waves such as kHz, is often used in batch processing. In addition, high frequency cleaning is performed at a higher frequency,
Ultrasonic waves in the z band are added to a fluid such as pure water, and fine particles (particles) on the surface of the object to be cleaned are removed by the rectilinear force of the particle acceleration, which is used for single-wafer cleaning in the pattern formation process. It is being appreciated. Is stated. " Note that this document also describes freon vapor drying.

On the other hand, "Precision Cleaning Equipment and Latest Applied Technology", Industrial Material Center, issued November 8, 1991, P476
And P477 describe the relationship between the surface tension of the cleaning liquid and the cavitation energy in ultrasonic cleaning. In this document, “Cavitation strength is reduced by reducing the surface tension of the cleaning liquid. From FIG. 12, it is understood that cavitation energy has a large factor of the surface tension (there are also factors of vapor pressure and viscosity). The surface tension of IPA (21.7 dyne / cm 2) and Freon 113 (17.3 dyne / cm 2) is small, and even if water is added with a surfactant of about 0.1%, it is 72
→ It becomes as small as 30 dyne / cm. Is stated. " Further, the graph of FIG. 12 shows the correlation between the surface tension and cavitation energy in amyl alcohol, toluene, phenol, aniline, and water.

[0005]

As described in the above literature, as one of the techniques for drying a wafer,
There is a vapor drying technology. In the vapor dryer, a treatment liquid such as IPA (isopropanol) contained in a vapor tank is heated to be vaporized, and a wafer is applied to the IPA vapor (vapor) to perform drying. IP condensed on the wafer surface
The A vapor contains a large amount of water and contains the treatment liquid (IPA
Liquid). The IPA liquid maintains a high purity at first, but the purity gradually decreases as the wafer is repeatedly dried, and the vaporization rate of the IPA liquid due to heating by the heater decreases. As a result, the drying of the wafer becomes insufficient and the drying efficiency also deteriorates. Therefore, the present inventors replace the IPA liquid by interrupting the drying process when the water content of the IPA liquid reaches, for example, about 5%.
However, when the water content in the treatment liquid is high, the vaporization rate is low, the amount of steam contributing to the drying is small, and the drying is insufficient. Moreover, the processing liquid extracted from the vapor tank is not used again for drying the wafer, which is uneconomical.

An object of the present invention is to provide a vapor drying apparatus which can always perform a stable drying process.

[0007] Another object of the present invention is to provide a vapor drying apparatus which can reuse and recycle the treatment liquid. The above and other objects and novel features of the present invention will be apparent from the description of the present specification and the accompanying drawings.

[0008]

The outline of the representative ones of the inventions disclosed in the present application will be briefly described as follows. That is, the vapor drying apparatus of the present invention has an opening door in the upper part and a processing liquid (IPA liquid) in the lower part.
A vapor tank for accommodating the above, a heater for heating and vaporizing the treatment liquid, a loader for carrying in and out an article to be dried in the treatment vapor (IPA vapor) in the upper part of the vapor tank, and a surface of the article to be dried. A saucer disposed in the vapor tank for receiving the IPA liquid that condenses and drops, a purifying tank containing an ultrasonic transducer and having a steam exhaust port at the top, and I in the saucer.
A drain pipe system for flowing the PA liquid into the purification tank, a drain pipe system for flowing the treatment liquid in the vapor tank into the purification tank, and a return pipe system for returning the purification treatment liquid in the purification tank to the vapor tank. Have In addition, an automatic opening / closing valve is provided in the two drain pipe systems so that the processing liquid flows into the refining tank as needed.
The return pipe system is equipped with a circulation pump and a filter. Further, the treatment liquid accumulated in the tray is sent to the purification tank at all times or at regular intervals or when the vapor drying treatment is not performed. The treatment liquid at the bottom of the vapor tank is sent to the refining tank at regular intervals or when the vapor drying process is not performed. When the processing liquid at the bottom of the vapor tank is sent to the refining tank at regular intervals, a predetermined amount of the processing liquid is sent to the refining tank so that an amount that does not interfere with the vapor drying process remains in the vapor tank. In such a device, ultrasonic vibration is applied to the treatment liquid containing water introduced into the purification tank to generate cavitation, whereby the water is vaporized and exhausted, and the water content is several percent. Refining treatment liquid of less than 1% is refluxed to the vapor tank.

[0009]

According to the above-mentioned means, the vapor drying apparatus of the present invention allows the IPA liquid having a large amount of water accumulated in the tray for receiving the IPA liquid condensed and falling on the surface of the material to be dried to flow into the purification tank, The IPA liquid with an increased water content at the bottom of the vapor tank is caused to flow into the purification tank, and the IP
Ultrasonic vibration is applied to the liquid A to promote vaporization of water by cavitation, and the water vapor is discharged from the water vapor exhaust port to the outside of the purification tank. Further, since the purified treatment liquid (purified IPA liquid) having a water content of several% to less than 1% is refluxed from the return pipe system to the vapor tank, the IPA liquid accumulated at the bottom of the vapor tank always has a low water content. Since a large amount of IPA vapor is constantly generated, a reliable drying process can be achieved. Further, since the vapor drying apparatus of the present invention circulates and uses the IPA liquid, there is no waste in using the IPA liquid as the treatment liquid and it is economical.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the outline of a vapor drying apparatus according to an embodiment of the present invention. As shown in FIG. 1, the vapor drying apparatus of the present invention roughly comprises a vapor tank 1 and a refining tank 30. Two drain pipe systems and a return pipe system are provided between the vapor tank 1 and the refining tank 30.

The vapor tank 1 has a box-like structure with an open top. An opening door 2 having a double door shape is provided in this opening. Further, the processing liquid 3, for example, the isopropanol (IPA) liquid 3 is stored in the vapor tank 1 to a midway depth. The IPA liquid 3 is pressure-fed and supplied from a supply pipe 4 attached to one side of the vapor tank 1. A heater 5 is provided on the bottom side of the vapor tank 1. The heater 5 heats and vaporizes the IPA liquid 3 in the vapor tank 1 (I
The boiling point of the PA liquid 3 is 82 ° C.). Then, the material to be dried 7 is dried by the vaporized IPA vapor 6 (indicated by dots). Further, a cooling spiral pipe 9 is provided on the upper part of the inner wall of the vapor tank 1.
Are provided over a certain height range. Since cooling water is caused to flow through the cooling spiral pipe 9, the opening space of the vapor tank 1 is cooled. As a result, the rising IPA vapor 6 solidifies and falls when it reaches the space area cooled by the cooling spiral tube 9.

An object to be dried 7 made of a wafer is a cassette 1
0 is stored in the loader 11 having a clamp structure, carried into the processing space 12 filled with the IPA vapor 6 and dried, and then carried out of the vapor tank 1. The loader 11 opens and closes the cassette 1 by opening and closing the pair of clamp claws 13.
It is designed to hold and release 0. Also, IPA
When the vapor 6 touches the surface of the wafer 7, it condenses and falls.
A tray 14 for receiving the dropped IPA liquid 3 is provided inside the vapor tank 1.

A column 15 for supporting the tray 14 is also provided.
Has a pipe shape and guides the IPA liquid 3 downward. Then, one end of a drain pipe 16 is connected to the column 15. The drain pipe 16 extends outside the vapor tank 1 and has a lower end protruding into the refining tank 30. An automatic opening / closing valve 17 is provided in the middle of the drain pipe 16. A drain pipe 18 is provided between the vapor tank 1 and the refining tank 30. The drain pipe 18 allows the IPA liquid 3 contained in the bottom of the vapor tank 1 to flow into the purification tank 30. An automatic open / close valve 19 is also provided in the middle of the drain pipe 18. These two drain pipe systems allow the IPA liquid 3 to flow into the purification tank 30 when the automatic opening / closing valves 17 and 19 are driven by being controlled by a controller (not shown). This IP
The liquid A can be flowed into the purification tank 30 at any time during the vapor drying, or at the stage when the vapor drying is completed. In each of the two drain pipe systems, by driving and opening the automatic on-off valves 17 and 19, respectively,
Each IPA liquid 3 can be made to flow into the purification tank 30. After the vapor drying process, the automatic open / close valve 17,
19 may be opened to allow all the IPA liquid 3 to flow into the purification tank 30, but during the vapor drying process, the IPA liquid 3 stored in the bottom of the vapor tank 1 is aside from the IPA liquid 3 in the tray 14. Since it is necessary to sequentially vaporize 3, the IPA liquid 3 cannot entirely flow into the purification tank 30. Therefore, during the vapor drying process, the IPA liquid 3 at the bottom of the vapor tank 1 has an amount of I that does not hinder the vapor drying process.
The PA liquid 3 is sent to the purification tank at regular intervals. During the vapor drying process, the IPA liquid 3 in the tray 14 may be constantly sent to the purification tank 30, or the automatic opening / closing valve 17 may be opened at a predetermined interval for a predetermined time so that the IPA liquid 3 is supplied to the purification tank 30.
The A liquid 3 may be sent.

The refining tank 30 has a closed box type structure.
A treatment liquid (IPA liquid) 3 having a high water content is sent from the two drain pipe systems. Also,
An ultrasonic oscillator (oscillator) 3 is provided on the bottom side of the purification tank 30.
1 is attached. In this example, ultrasonic vibration is I
Three pieces are provided so as to be added to the entire PA liquid 3. Further, these ultrasonic transducers 31 are covered with a cover 32. Further, the water vapor exhaust port 3 is provided on the upper side wall of the purification tank 30.
3 is provided. Further, a return pipe system is provided between the refining tank 30 and the vapor tank 1. The return pipe system includes a return pipe 34 for returning the IPA liquid 3 in the lower portion of the refining tank 30 to the upper portion of the vapor tank 1, and a pump 35 provided in the middle of the return pipe 34.
And a filter 36 provided between the pump 35 and the purification tank 30. Each part of the vapor dryer is made of a material having excellent chemical resistance, such as quartz, stainless steel, or tetrafluoroethylene.

In the refining tank 30, when the ultrasonic oscillator 31 is driven and ultrasonically oscillated, the IPA liquid 3 in the refining tank 30 causes cavitation due to ultrasonic vibration, and the IPA liquid 3 in the IPA liquid 3 is oscillated. Water vaporizes to steam 3
It becomes 7. That is, water has a large surface tension and cavitation energy as compared with IPA. Therefore, the breaking strength is large, and cavitation is likely to occur and vaporize easily. Therefore, the IPA liquid 3 remains at the bottom of the purification tank 30, but the water contained in the IPA liquid 3 is vaporized,
It becomes steam 37 and is exhausted from the steam exhaust port 33 to the outside of the purification tank 30. By continuing ultrasonic vibration,
The water content in the IPA liquid 3 contained in the purification tank 30 rapidly decreases. Therefore, the ultrasonic transducer 3
1 is driven, and when the water content becomes several percent to less than 1%, the ultrasonic transducer 31 is stopped and the pump 35 is driven to be stored in the bottom of the purification tank 30. The purification treatment liquid (purification IPA liquid) 39 is refluxed into the vapor tank 1. When the IPA liquid 3 (purification treatment liquid 39) in the purification tank 30 is refluxed by a predetermined amount, or the purification pipe 3 is continuously supplied from the drain pipe system connected to the tray 14.
In a state where the IPA liquid 3 is flown into 0, the ultrasonic transducer 31 is continuously driven to continue the steam generation. As a result, the water content of the IPA liquid 3 stored in the vapor tank 1 does not become 5% as in the conventional case but is several% to less than 1%, so that the vaporization of the IPA liquid 3 is performed efficiently. Therefore, the wafer 7 is effectively dried by the large amount of IPA vapor 6.

[0016]

EFFECTS OF THE INVENTION (1) In the vapor drying apparatus of the present invention, the treatment liquid is successively refined to remove water, so that the water content in the treatment liquid is low and the vaporization rate is high. Therefore, there is a large amount of processing vapor that comes into contact with the material to be dried, and the water on the surface of the material to be dried can be completely removed in a short time.

(2) According to the above (1), the vapor drying apparatus of the present invention purifies the treatment liquid having a high water content and returns it to the vapor tank for reuse, so that the treatment liquid is wasted. It is consumed without any cost and is economical.

(3) Due to the above (1) and (2), according to the present invention, there is a synergistic effect that it is possible to provide a vapor dryer having a low drying cost.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say, for example,
In the above-mentioned embodiment, the example applied to the separation of water in the isopropanol liquid has been described, but a cavitation energy threshold value by ultrasonic vibration may be selected to perform vaporization separation of liquids other than water. in this case,
The frequency of the ultrasonic waves may be converted, and each liquid may be vaporized and separated from the mixed liquid of two or more types and reused. Further, although the receiving tray is provided in the above-mentioned embodiment, the same effect as the above-mentioned embodiment can be obtained even in the structure without the receiving tray.

In the above description, the invention made by the present inventor was mainly applied to a vapor drying apparatus using isopropanol as a processing liquid, which is the field of application of the invention, but the invention is not limited thereto. It can also be applied to, for example, a vapor dryer using chlorofluorocarbon. INDUSTRIAL APPLICABILITY The present invention can be applied at least to the vaporization and separation technology of liquid that causes cavitation due to ultrasonic vibration.

[Brief description of drawings]

FIG. 1 is a sectional view showing an outline of a vapor drying apparatus according to an embodiment of the present invention.

[Explanation of symbols]

1 ... Vapor tank, 2 ... Opening door, 3 ... Treatment liquid (IPA liquid),
4 ... Supply pipe, 5 ... Heater, 6 ... Processing vapor (IPA vapor), 7 ... Wafer, 9 ... Cooling pipe, 10 ... Cassette,
11 ... Loader, 12 ... Processing space, 13 ... Clamp claw, 1
4 ... saucer, 15 ... pillar, 16 ... drain pipe, 17
... automatic open / close valve, 18 ... drain pipe, 19 ... automatic open / close valve, 30 ... purification tank, 31 ... ultrasonic transducer, 32 ... cover, 33 ... water vapor exhaust port, 34 ... return pipe, 35
... pump, 36 ... filter, 37 ... steam, 39 ... purification treatment liquid (purification IPA liquid).

Claims (3)

[Claims] 1. A vapor tank having an opening door in the upper part and containing a processing liquid in the lower part, a heater for heating and vaporizing the processing liquid in the vapor tank, and a processing vapor in the upper part of the vapor tank. A vapor drying apparatus having a loader for loading and unloading an article to be dried into a refining tank having an ultrasonic vibrator built-in and having a steam exhaust port at an upper portion, and a treatment liquid in the vapor tank is caused to flow into the refining tank. A vapor drying apparatus comprising: a drain pipe system and a return pipe system for returning the purification treatment liquid in the refining tank to the vapor tank. 2. The vapor tank is provided with a tray for receiving the processing liquid that condenses and drops on the surface of the material to be dried, and a drain pipe system for flowing the processing liquid accumulated in the tray into the purification tank. The vapor drying apparatus according to claim 1, further comprising: 3. The treatment liquid is isopropanol,
3. The vapor drying apparatus according to claim 1, wherein the refined treatment liquid is refluxed to the vapor tank in a state where the water content is several% to less than 1%.