JPH05111621A - Semipermeable membrane module - Google Patents

Abstract

PURPOSE:To obtain a semipermeable membrane module for removing moisture carried by an organic solvent and reusing the organic solvent by communicating a perforated suction surface with a vacuum suction nozzle from the inside over one side face of a plate rigid body and liquid-tightly fitting a flat semipermeable membrane on the perforated suction surface. CONSTITUTION:A plate rigid body consists of an upper surface perforated plate part 31-1 and an underside perforated plate part 31-2 where a lot of holes 38 are made in perforated surfaces each and their underside are abutted on each other equipped with projection 39 to prevent deflection due to vacuum and is equipped with a vacuum suction nozzle 37 on the side face. On the perforated plate surface of the plate rigid body 31 are fitted with semipermeable membranes 34 through plastic spacers of net structure. The membranes module thus obtained does not elute adhesive components from the module surface and is used for IPA drying in the semiconductor industry.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semipermeable membrane module, and more particularly to a pervaporation (hereinafter abbreviated as PV) method in a washing / drying apparatus using an organic solvent after washing wafers with water in a semiconductor manufacturing process. Alternatively, the present invention relates to a semipermeable membrane module used for reusing the organic solvent by removing water brought into the organic solvent by a vapor permeation (hereinafter abbreviated as VP) method.

[0002]

2. Description of the Related Art In an intermediate step of semiconductor manufacturing, for example, in a drying process which is performed after a wafer is processed and is followed by washing with water, which also serves as washing with vapor of isopropanol (hereinafter abbreviated as IPA). IPA sometimes used has a purity of 100% at the beginning of use.
The organic solvent evaporation tank (hereinafter abbreviated as “evaporation tank”) is charged into the organic solvent evaporation tank. However, once the IPA is used repeatedly, the water adhering to the dried material to be cleaned is brought into the IPA, Purity gradually decreases. Generally, when the purity of the IPA is 98% or less, stains due to impurities called water marks are generated on the wafer surface, etc., and the probability of becoming a defect as a semiconductor increases.

For this reason, it is normal practice to replace the IPA with a purity of 98% and replace it with 100% purity.
A technique has been developed for maintaining a required purity of IPA by providing a solvent regeneration device for removing water in IPA of which the purity is lowered. As a membrane module type mounted in the solvent regenerator, a flat membrane laminated type, a spiral type and a hollow fiber type are known. However, these membrane modules are installed outside the IPA dryer and the IA of the IPA dryer is
PA is introduced into the membrane module by a pump or gravity to regenerate the IPA.

FIG. 5 shows a flow sheet when the solvent regenerator according to the PV method of the prior art is installed in the IPA dryer. That is, the method shown in FIG. 5 includes a solvent replenishing pipe 1 and a cooler 5 for condensing the vapor of the solvent 2, and the vapor of the solvent 2 heated by the heater 4 removes an object to be cleaned 6 such as a semiconductor wafer. A solvent regenerator equipped with a PV membrane module 9 is attached to the outside of the evaporating tank 3 that has been cleaned, and a solvent containing impurities is removed from the liquid delivery pump suction pipe 7 by a pump 8 to a PV
The solvent sent to the membrane module 9 and regenerated is returned to the evaporation tank 3 through the solvent return pipe 10. Further, the membrane permeate is guided by a vacuum pump 15 equipped with an exhaust pipe 16 through a vacuum pump suction pipe 11 to a condenser 12 equipped with a cooling water pipe 13 through which cooling water flows, and is cooled and condensed to be a drain pipe. Emitted from 14.

The apparatus shown in FIG. 5 is always provided with a pump 8 for feeding the solvent into the PV membrane module 9. However, the pump is designed to prevent the mixing of a trace amount of metal or metal ions into the solvent, It is not possible to use metal in the parts that come into contact with, and some fine particles are generated. Furthermore, since the solvent has a risk of being easily ignited by static electricity, it is necessary to provide a safety measure. That is, in reality, the pump has various problems in selection and safety. In addition, when the solvent regenerator is added to the existing evaporation tank to be installed side by side, it may be difficult to install the solvent regenerator, and there is a demand for downsizing of the solvent regenerator.

The present inventors have found a method for regenerating the IPA without using the above-mentioned pump and have already filed a patent application (Japanese Patent Application No. 2-297923). This method is
This is a method of using a solvent regenerator in which the P membrane module is arranged in the vapor layer of the evaporation tank, and its flow sheet is shown in FIG. That is, the method shown in FIG. 6 includes a cooler 5, the solvent 2 supplied from the solvent replenishing pipe 1 is heated by a heater 4, and the vapor thereof cleans an object to be cleaned 6 such as a semiconductor wafer. A VP membrane module 9 ′ whose permeate side is decompressed by a vacuum pump 15 having an exhaust pipe 16 is arranged in the vapor layer of the membrane, and the membrane permeate is led out of the evaporation tank 3 by a vacuum pump suction pipe 11 to cool water. It is a method of condensing with a condenser 12 cooled by cooling water with a pipe 13 and discharging from a drain pipe 14.

However, the conventional PV or VP membrane module was developed for the purpose of supplying the separation liquid or the separation gas mixture to the semipermeable membrane module, and the separation liquid or the separation gas mixture is provided without a supply pump. Even if only the semipermeable membrane module was installed inside, the separation liquid or the separation gas mixture was not sufficiently supplied to the membrane surface, and high separation performance could not be obtained.

[0008]

The present inventors have completed the present invention as a result of intensive research to solve the above problems. That is, the present invention is a flat plate-like semipermeable membrane module for separating a gas mixture or a liquid mixture, which is substantially a membrane-shielding cover and forms a main skeleton of the membrane module structure, and at least one side of which has a perforated suction. Of a flat plate-shaped rigid body having a membrane permeate passage portion which is a surface and which communicates with the hole portion of the perforated suction surface and also communicates with a vacuum suction nozzle for collecting the membrane permeate provided on the side surface. A semipermeable membrane, characterized in that a flat membrane semipermeable membrane is liquid-tightly attached to a perforated suction surface with or without a porous spacer and is installed in a gas mixture or a liquid mixture. The module is for gist.

In the structure of the semipermeable membrane module according to the present invention, a flat membrane semipermeable membrane is attached to at least one surface of a flat plate-like rigid body so as to be substantially uncovered, and provided on the side surface of the flat plate-like rigid body. It has a structure to collect the substance that has permeated through the semipermeable membrane by sucking it from the vacuum suction nozzle, so that the gas mixture or liquid mixture to be subjected to membrane separation can be supplied to the membrane surface without using a supply pump. It is a thing. In addition,
When the membrane area is insufficient for one module, the modules can be used in multiple layers at intervals.

The perforated suction surface of the flat rigid body referred to in the present invention means any shape as long as it has a hole capable of suction.
It may be in the form of, for example, a porous plate surface having a large number of holes, a surface having a mesh-like structure, or a surface having a sintered porous body almost entirely or partially. .. Further, the plate-shaped rigid body does not need to be a perfect flat surface in particular, and may be curved or corrugated. Further, inside the flat plate-like rigid body, there is a membrane permeate circulation part that communicates with the hole of the perforated suction surface and also communicates with the vacuum suction nozzle for collecting the membrane permeate provided on the side surface. The part may be, for example, a substantially hollow space when the perforated suction surface is made of a porous plate, or may be a passage connecting to these when it is made of a surface having a large number of portions made of a sintered porous body. ..

The flat membrane semipermeable membrane is attached to the perforated suction surface of the flat rigid body according to the present invention with or without a porous spacer such as a net structure made of plastics, for example, ultrasonic waves or the like. By heat welding, crimping with a rigid holding frame, or both methods, or using a rigid holding frame as a flange type, crimping with bolts and nuts or vise through a sealing material such as packing or liquid sealant. It should be held in a liquid-tight manner. The rigid holding frame used in the present invention may have any shape and form as long as it has a porosity that does not substantially prevent the supply of the substance to be separated to the membrane surface, for example, a net shape. Examples thereof include a flat plate having a large opening window.

Embodiments of the membrane module of the present invention will be described below with reference to the drawings. FIG. 1 shows a plan view of an example of a semipermeable membrane module according to the present invention. FIG. 2 is a sectional view taken along the line AA of the central portion of FIG. 1 and has a vertically symmetrical structure.
The flat plate-shaped rigid body 31 has a porous surface having a large number of holes 38 formed therein, and a porous surface 31 having an upper surface provided with a convex portion 39 for preventing bending due to vacuum by abutting the porous surfaces on their back sides. -1 and a perforated plate portion 31-2 on the lower surface, the periphery of which is welded by ultrasonic waves, a vacuum suction nozzle 37 is provided on the side surface, and the inside is substantially hollow. Here, in FIGS. 1 and 2, reference numerals -1 and -2 indicate the same members on the upper surface and the lower surface in the case of a structure in which semipermeable membranes are mounted on both sides, and therefore will not be described below.
The flat membrane semi-permeable membrane 34 is sandwiched between the back packing 32 and the front packing 35 by the spacer 33 having a net structure made of plastics on the porous plate surface of the flat rigid body 31, and is crimped by the holding frame 36, Be assembled. Both packings may be ultrasonically welded. In FIGS. 1 and 2, a rigid plate-like body
Although an example in which the periphery of 31 and the holding frame 36 is welded by ultrasonic waves has been shown, the holding frame 36 may be a flange type and may be tightened with bolts and nuts or with a vise. A vacuum suction nozzle 37 attached to the side surface of the module is connected to a vacuum system to reduce the pressure on the permeate side of the semipermeable membrane. When fixing the semipermeable membrane 34 with the holding frame 36, in order to protect the surface of the holding frame 36 and the semipermeable membrane 34,
It is also possible to laminate a film on the contact portion of.

FIG. 3 is a plan view showing another embodiment according to the present invention, and FIG. 4 is a sectional view taken along the line BB of the central portion of FIG. In the flat plate-shaped rigid body 51, a net-like or fine spherical sintered porous plate 52 is embedded in a large number of recesses provided on the surface thereof, and a membrane permeate sampling port opened at the center of the recesses is provided. Each communicates with a passage formed therein and also communicates with a vacuum suction nozzle 58. Semipermeable membrane 55
Via a plastic mesh spacer 53 on the surface of the flat rigid body 51, the back packing 54 and the front packing 56.
It is sandwiched between the two and is pressed and attached by the pressing frame 57. 3 and 4, the rigid plate 51 and the holding frame
An example in which the periphery of 57 is welded by ultrasonic waves was shown.
57 may be a flange type and may be tightened with bolts and nuts or with a vise.

[0014]

The membrane module according to the present invention has little or no elution of the adhesive component from the surface of the module, so that it is less contaminated by the solvent, and in the IPA drying of the water-washed wafer in the semiconductor industry, There is little accumulation of eluate in IPA of substances that pollute wafers. Furthermore, although the space inside the evaporation tank of the IPA dryer is small, the membrane module according to the present invention can be installed in the evaporation tank of the IPA dryer because it is space-saving because it can be thinned to 4 cm or less. It's easy.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a semipermeable membrane module according to the present invention.

FIG. 2 is a sectional view taken along the line AA of the central portion of FIG.

FIG. 3 is a plan view showing another example of the semipermeable membrane module according to the present invention.

4 is a cross-sectional view taken along the line BB of the central portion of FIG.

FIG. 5 is a flow sheet showing a conventional solvent regeneration method in which a solvent regeneration device is attached outside the evaporation tank.

FIG. 6 is a flow sheet showing a solvent regeneration method in which a VP membrane module is arranged in a vapor layer of an evaporation tank.

[Explanation of symbols]

 1 Solvent Replenishing Pipe 2 Solvent 3 Evaporating Tank 4 Heater 5 Cooler 6 Object to be Washed 7 Liquid Pump Suction Pipe 8 Liquid Pump 9 PV Membrane Module 9'VP Membrane Module 10 Solvent Return Pipe 11 Vacuum Pump Suction Pipe 12 Condenser 13 Cooling Water Pipe 14 Drain pipe 15 Vacuum pipe 16 Exhaust pipe 31-1 Top porous plate part 31-2 Bottom porous plate part 32-1 Top back packing 32-2 Bottom back packing 33-1 Top plastic mesh Structural spacer 33-2 Plastic net-structured spacer on the lower surface 34-1 Semi-permeable membrane on the upper surface 34-2 Semi-permeable membrane on the lower surface 35-1 Front packing on the surface 35-2 Front packing on the lower surface 36-1 Top surface Presser frame 36-2 Lower presser frame 37 Vacuum suction nozzle 38 Perforated plate hole 39 Convex portion 51 Flat plate rigid body 52 Net or sintered perforated plate 53 Plastic net spacer 54 Back packing 55 Semi-permeable membrane 56 Front packing 57 Holding frame 58 Vacuum suction nozzle

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kazuo Mihara, Kazuo Mihara 966-35, Taiko-cho, Ibo-gun, Hyogo Prefecture (72) Kyoshi Maeda, 500 Kamamiyo-ku, Yobu-ku, Himeji-shi, Hyogo (72) Masashi Yamamoto, Tokyo 5-20-1 Kamimizuhoncho, Kodaira-shi Incorporated Hitachi, Ltd. Musashi Plant (72) Inventor Seiichi Ishii 5-20-1 Kamimizuhoncho, Kodaira-shi, Tokyo Incorporated Hitachi Ltd. Musashi Plant (72 ) Inventor Yoshiro Niimura 5-20-1 Kamimizuhoncho, Kodaira-shi, Tokyo Inside Musashi Factory, Hitachi Ltd. (72) Inventor Katsuhiro Mitsuta 5-20-1 Kamimizuhoncho, Kodaira-shi, Tokyo Hitachi Ltd. Factory Musashi Plant (72) Inventor Hideki Shirai 29-16 Tsurutacho, Utsunomiya City, Tochigi Prefecture

Claims (5)

[Claims] 1. A flat plate-like semipermeable membrane module for separating a gas mixture or a liquid mixture, which is substantially free of a membrane shield and constitutes a main skeleton of the membrane module structure, and at least one side of which is a suction surface having a hole. And a flat plate-shaped rigid body internally having a permeation portion of the membrane permeate that communicates with the hole portion of the perforated suction surface and also communicates with a vacuum suction nozzle for collecting the membrane permeate provided on the side surface. For a semipermeable membrane, characterized in that a flat membrane semipermeable membrane is liquid-tightly attached to the pore suction surface with or without a porous spacer, and is installed in a gas mixture or a liquid mixture for use. module. 2. The plate-like rigid body is a perforated suction surface having a porous surface, a mesh surface or a sintered porous body surface, at least one surface of which is provided with a large number of holes, and the inside thereof is substantially The semipermeable membrane module according to claim 1, wherein the module is a flow section including a cavity or a passage. 3. The flat membrane semipermeable membrane is attached to the perforated suction surface of the plate-shaped rigid body by thermal welding, pressure bonding with a rigid holding frame, or both methods. Module for semi-permeable membrane. 4. The crimping of the flat film semipermeable membrane by the rigid pressing frame is performed by pressing and holding the flange type pressing frame with a bolt and nut or a vise through a sealing material. Item 3. The semipermeable membrane module according to Item 3. 5. The semipermeable membrane module is used for removing water components from the vapor or a liquid condensed by the vapor when the water adhering to the semiconductor wafer is replaced with the vapor of isopropanol and dried. Claims 1 to 4
The semipermeable membrane module according to any one of claims 1 to 4.