JP2000084368A - Multiple hollow fiber membrane for liquid chemical deaeration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multiple hollow fiber membrane for liquid chemical deaeration free from the leakage of a liquid chemical in deaeration, allowing high permeation flow rates of oxygen and nitrogen and capable of forming a compact device. SOLUTION: The multiple hollow fiber membrane for liquid chemical deaeration is a multiple structural hollow fiber membrane formed by holding a homogeneous thin film 2 between polyolefin based porous supporting body layers 1 and is constituted so that the homogeneous thin film 2 and the porous supporting body layer 1 are in contact with each other without sticking to each other, the liquid chemical is fed to one surface of the hollow fiber membrane, the opposite surface of the hollow fiber membrane is made negative in pressure to the liquid chemical supply surface and, at the time of deaerating dissolved gases in the liquid chemical, the leakage of the liquid chemical from the negative pressure side membrane surface is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber membrane for degassing a chemical solution and a method for degassing a chemical solution, and more particularly to a chemical solution (a photoresist solution, a developing solution, a chemical solution for a spin-on-glass process, etc.) in a semiconductor manufacturing process. ) And a hollow fiber membrane for deaeration of ink for an ink jet printer, and a method for deaeration of these chemical solutions.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, inconveniences such as processing unevenness may be caused by mixing air bubbles into a supplied chemical solution. For example, a photoresist solution is applied to a thin film laminated on a semiconductor wafer, exposed through a patterned mask, developed, and then etched to form a pattern in the thin film. When a resist solution or a developing solution is spin-coated on a semiconductor wafer, troubles such as pattern defects due to processing unevenness occur. Further, when bubbles were mixed in the cleaning liquid in the cleaning operation in the lithography process, cleaning spots were generated.

As a cause of the inclusion of bubbles, the chemical is sent under pressure to the discharge nozzle with nitrogen gas. When the chemical is discharged from the nozzle, the pressure applied to the chemical returns to atmospheric pressure, so that the dissolved gas becomes supersaturated. May become bubbles. The generation of such bubbles can be suppressed by reducing the amount of dissolved gas by a technique such as film-type degassing during the chemical solution pumping step.

The following method has been known as a technique relating to degassing of dissolved gas in a solvent using a membrane. (1) A method for degassing dissolved nitrogen in a chemical solution using a porous hollow fiber membrane having a communication hole from the inner surface to the outer surface
8-243306, JP-A-09-94447, JP-A-09-94447
9-7936, JP-A-01-199607, JP-A-64
-7915, JP-B05-57478, JP-B05-4
5282). (2) Uniform thin film layer on the surface (thin film layer without communicating holes)
A method for degassing dissolved nitrogen in a chemical solution using a heterogeneous hollow fiber membrane supported by a porous support layer composed of the same polymer as a homogeneous thin film layer (Japanese Patent Laid-Open No. 09-9 / 1990)
4447, JP-A-09-187629, JP-A-06-2
78897). (3) A method of degassing dissolved nitrogen in a chemical solution using a non-porous (homogeneous) tube membrane formed of a tube made of tetrafluoroethylene resin having excellent solvent resistance (JP-A-08-153)
675, JP-A-08-243306, JP-A-09-79
36, JP-A-05-267149, JP-A-07-318
04, JP-A-09-57008, JP-A-08-1248
75, Japanese Utility Model Laid-Open No. 02-9160). (4) A method of degassing dissolved nitrogen in a chemical solution using a double-layered composite hollow fiber membrane in which a homogeneous thin film is laminated on a porous support (Japanese Utility Model Application Laid-Open No. 02-91601, Japanese Patent Application Laid-Open No. 08-24330)
6, JP-A-09-94447, JP-A-64-6800
7). (5) A non-porous membrane made of a fluororesin is sandwiched between porous support layers made of a fluororesin, and the respective layers are adhered to each other to remove dissolved nitrogen in the chemical solution by using an integrated three-layer hollow fiber membrane. (Japanese Unexamined Patent Publication (Kokai) No. 64-63007).

[0005]

However, according to the method (1), when the liquid to be treated is supplied from the primary side of the film, the liquid to be treated penetrates into the fine pores and the film is not wetted if the film material and the chemical liquid are well wetted. The liquid to be treated leaks from the next side (opposite side) and degassing cannot be performed.
In particular, this phenomenon was remarkable when the chemical solution was a semiconductor chemical solution or an ink jet ink.

In the method (2), it is difficult to completely disturb the crystal orientation of the homogeneous thin film layer in the spinning process, and some crystal orientation ordered structure is formed. Connected pores were easily formed. Also, in the handling after the production of the film, pinholes were liable to occur in the homogeneous thin film layer due to mechanical rubbing. Therefore, in such a film, after the liquid to be treated permeates into the porous pores, the liquid to be treated leaks from the pores and pinholes of the homogeneous thin film layer, and degassing cannot be performed. In particular, when the chemical was a semiconductor chemical or an inkjet ink, leakage of the chemical was remarkable.

In the method (3), the nitrogen permeability coefficient of the membrane material is reduced.
In addition to the low
Low nitrogen permeation flow rate (for example, nitrogen permeation flow rate = 0.5 ×
10 ^-11cm^Three/ (Cm^Two・ Pa ・ sec)), degassing
Even if the dissolved gas concentration is only about 90% of the saturation concentration
It does not decrease, and it is not enough as a practical deaeration level.

In the method (4), since the homogeneous thin film material and the porous support material both satisfy solvent resistance and are chemically inert, it is difficult to bond both layers with an adhesive.
For this reason, although both layers are integrated by fusion, pinholes tend to occur in the homogeneous thin film in the fusion step. Since the liquid to be processed leaks from the generated pinhole, degassing tends to be insufficient.

In the method (5), the thickness of the non-porous membrane is increased by the thickness of the adhesive, and the gas permeation resistance is increased. It is easy to practically lack deaeration performance. In addition, when bonding and integration are performed, pinholes are generated in the thin film, and the liquid to be treated may leak out as described above.

Also, in an ink jet printer, when the piezo elements in the ink head (ink chamber) are repeatedly pressurized and depressurized many times during ejection of ink, dissolved gases such as dissolved oxygen and nitrogen in the ink stay in the ink chamber. Easy,
It is known that printing of ink may cause printing loss.

As a method for degassing the dissolved gas in the ink by means of a film, a reduced pressure space and an ink filling space are provided in the ink discharge head section by a flat membrane partition, and the gas dissolved in the ink is degassed by this diaphragm. The method is Tokuhei 07-37137
Is disclosed. However, the film area that can be mounted on the head is limited due to the speed of driving the ink jet printer head, and the permeation flow rate of oxygen and nitrogen is about 1-3 × 10 ⁻¹⁰ cm ³ / in the film material disclosed therein. (Cm ² · Pa
Sec), and it is difficult to sufficiently degas the dissolved gas to be degassed.

Japanese Patent Application Laid-Open No. 05-17712 discloses a method in which a raw material ink is supplied to the hollow portion of a hollow fiber membrane, the outside of the membrane is depressurized, and the dissolved gas in the ink is selectively degassed through the membrane. . However, the film thickness of the tetrafluoroethylene tube used in the example is as very thin as 1 to 2 μm. When an ink material flows from the inside of this film to this film,
The film is pushed outward by the flow of the ink.
Under this force, the film thickness was very thin, and the mechanical strength of the film was insufficient, so that the film was likely to be broken and the liquid to be treated leaked.

It is an object of the present invention to provide a composite hollow fiber membrane for chemical solution degassing which does not cause leakage of the chemical solution at the time of degassing, has a large permeation flow rate of oxygen and nitrogen, and can form a compact device. It is in.

[0014]

That is, the present invention relates to a hollow fiber membrane having a composite structure in which a homogeneous thin film is sandwiched between polyolefin-based porous support layers, wherein the homogeneous thin film and the porous support layer do not adhere to each other. When a chemical solution is supplied to one surface of the hollow fiber membrane and the opposite surface of the hollow fiber membrane is negatively pressured with respect to the chemical solution supply surface to degas dissolved gas in the chemical solution, a negative pressure side is provided. This is a composite hollow fiber membrane for chemical solution degassing in which the chemical solution does not leak from the membrane surface.

In particular, this composite hollow fiber membrane is JIS K71
The rate of weight change after immersion in the chemical solution according to No. 14 is 0 to +3
0%, and the flow ratio of the oxygen permeation flow rate to the nitrogen permeation flow rate is 1.1 or more;
It is preferable that the rate of change of the flow rate ratio after immersion in a chemical solution according to IS K7114 is within ± 10%.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below.
FIG. 1 is a schematic view showing a composite hollow fiber membrane for degassing a chemical solution of the present invention.

In the composite hollow fiber membrane for deaeration of a chemical solution of the present invention, the homogeneous thin film and the polyolefin-based porous support layer are not adhered by an adhesive and are not thermally fused. When an adhesive is interposed between the porous support layer and the homogeneous thin film, the adhesive layer hinders gas permeability, thereby substantially reducing the gas permeability of the composite hollow fiber membrane, and deteriorating the degassing performance. It is inappropriate because it causes In addition, when the homogeneous thin film and the porous support layer are heat-sealed and integrated without an adhesive, a part of the thin film is locally melted by heat to form micropores. It is inappropriate because the liquid leaks through.

The composite hollow fiber membrane of the present invention has a structure in which both surfaces of a homogeneous thin film having no pinholes or micropores are sandwiched between the porous support layers without being adhered to each other. Although only the thin films are arranged in abutting state,
The composite hollow fiber membrane has a stable form even when used for degassing chemicals. The phrase "the chemical does not leak from the negative pressure side membrane surface" in the present invention means that there is no pinhole in the homogeneous thin film, and therefore, the liquid chemical does not leak to the negative pressure side through the pinhole. are doing.

The composite hollow fiber membrane of the present invention needs to have chemical resistance to a chemical solution for degassing. Here, JIS K7
Chemical resistance was evaluated by the index of formulas (1) and (2) under the Watase method according to No.114. Specifically, after immersing the composite hollow fiber membrane in a chemical solution, the weight change rate (formula 1) is 0 to + 30%.
The composite hollow fiber membrane is degassed when the change rate of the oxygen permeation flow rate / nitrogen permeation flow rate (Equation 2) of the composite hollow fiber membrane after immersion is within ± 10% of that before immersion. It has sufficient chemical resistance inside.

[0020]

(Equation 1)

[0021]

(Equation 2)

In the present invention, since the porous support layer is made of a polyolefin polymer, there is no problem in chemical resistance to a chemical solution, and the change in weight of this layer before and after immersion in the chemical solution is almost zero. As the polyolefin constituting the porous support layer, polyethylene, polypropylene, poly (4
-Methylpentene-1), polyvinylidene fluoride and polyoxymethylene.

The weight change rate of the composite hollow fiber membrane of the present invention in the formula (1) substantially represents the weight change of the homogeneous thin film. If the value is within 0 to + 30%, pinhole formation due to swelling is caused. No mechanical strength is maintained for practical use, and no chemical leakage occurs. On the other hand, when the rate of change in weight is smaller than 0%, this corresponds to the case where the film is dissolved and a pinhole is formed, and is unsuitable because the liquid leaks. When the weight change rate is more than + 30%, the degree of swelling of the film is large, the mechanical strength is reduced, and the film is broken if degassing is performed for a long time.

The flow ratio of the oxygen permeation flow rate to the nitrogen permeation flow rate is obtained from another viewpoint of the chemical durability of the homogeneous thin film. First, it was found that this flow rate ratio should be within 1.1 before immersion in a practically suitable composite hollow fiber membrane. If this value is smaller than 1.1, it corresponds to the fact that a pinhole has already been formed in a part of the film. In particular, when this value is smaller than 0.93, a pinhole having a size close to the mean free path of oxygen or nitrogen molecules is formed in the entire homogeneous thin film, and the chemical solution easily leaks through this pinhole and is inappropriate. is there. Further, if the rate of change of the flow ratio represented by the equation (2) after immersion is within ± 10%,
It has been found that the homogeneous thin film is durable against the chemical and can be used sufficiently for degassing the chemical. If the decrease is more than -10%, pinholes are formed in the homogeneous thin film, and if the increase is more than + 10%, there is a conformational change of the polymer due to swelling, and the mechanical strength of the homogeneous thin film decreases. It's easy to do.

In order to degas the solvent gas in the chemical solution to a practically sufficient level with a homogeneous thin film, the nitrogen gas permeation flow rate must be 0.5
It is necessary to be not less than × 10 ^-9 cm ³ / (cm ² · Pa · sec), and the oxygen permeation flow rate is 0.5 × 10 ^-9
It is necessary to be not less than cm ³ / (cm ² · Pa · sec). When the oxygen and nitrogen permeation amounts are smaller than the above values, sufficient deaeration cannot be performed due to insufficient gas permeation flow rate of the homogeneous thin film. If the gas permeation flow rate is equal to or more than the above, the dissolved nitrogen gas and oxygen gas of the chemical solution are degassed by (gas concentration of dissolved oxygen or nitrogen gas after degassing) / (oxygen or nitrogen gas to the chemical solution at atmospheric pressure) Solubility) can be 0.5 or less.

This index indicates a practical level of deaeration,
If this value is greater than 0.5, when the chemical is exposed to another decompression step, the dissolved gas from the chemical tends to become bubbles,
The level of deaeration is not enough. In addition, in ink jet printer inks, a particularly high degassing level may be required in order to prevent print omission, and the above value is preferably set to 0.05 to 0.1.

The thickness of the homogeneous membrane of the composite hollow fiber membrane for degassing a chemical solution of the present invention is preferably in the range of 0.5 to 10 μm. When the thickness is less than 0.5 μm, the pressure resistance tends to be insufficient during use, and when the thickness is more than 10 μm, the gas permeability tends to be insufficient depending on the material used. The thickness of the polyolefin-based porous support layer is 10 to 200 in one of the inner layer and the outer layer.
μm is preferred. If the porous support layer is thinner than 10 μm, the mechanical strength tends to be insufficient. Also, 20
When the thickness is larger than 0 μm, the outer diameter of the hollow fiber membrane is large, and the volume efficiency of the membrane becomes low when the hollow fiber membrane is incorporated in a membrane module.

The composite hollow fiber membrane of the present invention is obtained by a multilayer composite spinning step and a drawing porous step. Specifically, for example, the molten polymer for the outermost layer nozzle portion and the innermost peripheral nozzle portion of the concentric composite structure nozzle die, the support layer precursor (unstretched layer) is supplied, and the molten polymer for the homogeneous film is supplied to the intermediate layer nozzle portion. And the molten polymer is extruded from a concentric die and cooled and solidified in a drafted state to obtain an undrawn hollow fiber. Next, the undrawn hollow fiber is drawn, and the outer layer portion of the undrawn hollow fiber is made porous. Although the draw ratio varies depending on the polymer used, it is usually 2 to 10 times that of the undrawn fiber. If it is lower than twice, the porosity of the porous support layer becomes lower than the above lower limit, and it is difficult to obtain a sufficient gas permeability. 1
When it is larger than 0 times, the elongation at break of the composite hollow fiber membrane is low,
It is likely to be a problem in practical use.

As the material for the homogeneous membrane of the composite hollow fiber membrane for chemical solution degassing which satisfies the above-mentioned chemical resistance and gas permeability, the following five types of thermoplastic polymers are particularly suitable.

[1] Polymer composed of a molten mixture of a styrene-based thermoplastic elastomer and a polyolefin The styrene-based thermoplastic elastomer referred to in the present invention is a block copolymer composed of styrene and olefin.
The polystyrene block of this styrene-olefin block copolymer is in a glassy state at room temperature and forms a hard domain, the polyolefin block is in a rubbery state at room temperature and forms a soft domain, and the two domains are in a microphase separated state. . This copolymer has melt fluidity at a temperature higher than the glass transition temperature of the styrene block polymer, and when cooled and solidified, the polystyrene domain serves as a pseudo-crosslinking point, and the polyolefin block polymer connects the crosslinking point to the network structure. You are. When a polyolefin is melt-mixed with this thermoplastic elastomer and solidified by cooling, the microcrystalline portion of the polyolefin molecular chain forms a pseudo-crosslinking point, and the two networks of the styrene thermoplastic elastomer and the polyolefin penetrate each other. It has been found that a "penetrating network structure" is formed, and the network structure ensures chemical resistance. The polyolefin blocks that constitute the styrene-based thermoplastic elastomer include ethylene propylene,
Examples include butylene and the like. Examples of the styrene-based thermoplastic elastomer include a styrene-ethylene block copolymer, a styrene-ethylene-butylene block copolymer, and a styrene-ethylene-propylene copolymer. Polyolefins include low-density polyethylene, ethylene-propylene copolymer, and metallocene-catalyzed low-density polyethylene (for example, EN manufactured by DuPont Dow).
GAGE).

In order to melt-mix a styrene-based thermoplastic elastomer and a polyolefin to form an interpenetrating network structure upon cooling and solidification, it is necessary to sufficiently knead the mixed polymer with a twin-screw kneader or the like. The mixing ratio of the two components can be appropriately determined in consideration of gas permeation performance and chemical resistance. For example, styrene-based thermoplastic elastomer / polyolefin = 20 / 80-
An 80/20 (% by weight) composition is mentioned as an example. For this homogeneous membrane, as a polymer for a porous support layer,
A material selected from high density polyethylene, high stereoregularity polypropylene, poly (4-methylpentene-1) and polyoxymethylene is used.

[2] Copolymer of (2,2-bistrifluoromethyl-4,5-difluoro-1,3-dioxole) and tetrafluoroethylene This polymer is in a glassy state at room temperature but can be melt-spun. It is. (2,2-bistrifluoromethyl-
The mixing ratio of 4,5-difluoro-1,3-dioxole and tetrafluoroethylene is 50/50 to 90/10
(Mol%) and when the thickness of the thin film is 0.5 to 5 μm, the nitrogen permeation flow is 0.5 × 10 ⁻⁹ cm ³ / (cm ² · Pa
・ Sec) or more. When the copolymerization ratio is 49/51 to 1 /
In the case of 99, the gas permeability is low and inappropriate. When the copolymerization ratio is from 91/9 to 99/1, the thin film tends to be brittle, and this is put to practical use. When the film thickness is smaller than the above-mentioned value, the thin film is broken at the time of handling, and a pinhole is easily generated. When the thickness is larger than the above value, the nitrogen permeation flow rate of the thin film is 0.5 ×
It tends to be smaller than 10 ^-9 cm ³ / (cm ² · Pa · sec). For this homogeneous membrane, the porous support layer is appropriately selected from poly (4-methylpentene-1), polypropylene and polyvinylidene fluoride for use.

[3] Fluorine-based thermoplastic elastomer The fluorine-based thermoplastic elastomer referred to in the present invention has a hard segment made of a fluorine resin and a soft segment made of a fluorine rubber. Ethylene-tetrafluoroethylene copolymer or polyvinylidene fluoride is used for the fluorine resin of the hard segment, and vinylidene fluoride-hexafluoropropylene binary copolymer or vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene is used for the soft segment. A fluoroethylene terpolymer is used. As a specific example, Daiel Thermoplastic (trade name, manufactured by Daikin Industries, Ltd., composition: hard segment is ethylene-tetrafluoroethylene copolymer, and soft segment is pinylidene fluoride-hexafluoropropylene binary copolymer) Can be used. In this case, a highly stereoregular polypropylene, a highly crystalline poly (4
-Methylpentene-1) and polyvinylidene fluoride.

[4] Poly (4-methylpentene-1) or 4-methylpentene-1 copolymer In the present invention, the 4-methylpentene-1 copolymer includes 4-methylpentene-1 and a higher olefin. (For example, an α-olefin such as octene)
Specific examples include TPX MX001 (trade name, manufactured by Mitsui Chemicals, Inc.). It is important to lower the degree of crystallinity in a homogeneous film of this polymer. The degree of crystallinity is preferably 60% or less. 60% crystallinity
If it exceeds 300, the gas permeability tends to be insufficient. As the porous support layer, highly crystalline poly (4-methylpentene-
1) Homopolymer or highly crystalline (4-methylpentene-1)-(α-olefin) copolymer (for example, TPX
RT31, trade name, manufactured by Mitsui Chemicals, Inc.) or polyvinylidene fluoride.

[5] Polyolefin-based thermoplastic elastomer The polyolefin-based thermoplastic elastomer referred to in the present invention is a copolymer composed of only polyolefin, for example, a copolymer of ethylene and octene, and a copolymer of propylene and octene. And a copolymer of ethylene and propylene. Examples of the porous support layer include high-density polyethylene, high stereoregularity polypropylene, and polyoxymethylene.

The chemical liquid to be degassed by the composite hollow fiber membrane for degassing of the present invention includes organic solvents such as methanol, ethanol, isopropyl alcohol, butanol, methyl ethyl ketone, ethyl cellosolve, ethyl lactate and propylene glycol monomethyl ether acetate. , Chemically amplified positive photoresist solution, naphthoquinonediazide-based positive photoresist, developer solution for semiconductors in which tetramethylammonium hydroxide is dissolved in water, ink for inkjet printers in which dyes are dispersed, inkjet printers in which pigments are dispersed Inks can be mentioned. The chemically amplified positive photoresist solution is a methacrylic acid-based resin having an alicyclic adamantyl group and a cyclic ketone (oxocyclohexyl) group in a side chain, or copolymerization of methacrylic acid ester of mevalolactone and methyl adamantyl methacrylate with ethyl lactate. It is a solution dissolved in propylene glycol monomethyl ether acetate.

The naphthoquinonediazide-based positive photoresist is obtained by converting a naphthoquinonediazide-based polymer to ethyl lactate,
It is a solution dissolved in propylene glycol monomethyl ether acetate.

The ink for an ink jet printer is a solution in which a dye or pigment is dissolved in a mixed solvent such as water, ethylene glycol, isopropyl alcohol, N-methylpyrrolidone, and methyl ethyl ketone.

Table 1 shows the solubility of oxygen and nitrogen in the above chemical solutions. This table is based on the values described in the Chemical Handbook (Maruzen) and the values measured by the present inventors. The measurement was performed by a gas chromatography analysis method. The dissolved gas concentration described in the examples of the present specification is also based on a gas chromatographic analysis technique.

[0040]

[Table 1]

Degassing of a chemical solution using the composite hollow fiber membrane of the present invention is usually performed using a composite hollow fiber membrane formed as a hollow fiber membrane module. The hollow fiber membrane module bundles, for example, hundreds of hollow fiber membranes, inserts them into a cylindrical housing, and allows the sealing material to penetrate into the outer porous pores of the composite hollow fiber membrane while passing between the adjacent hollow fiber membranes. It can be manufactured by filling with a sealing material.

An example of a specific method of degassing a chemical solution will be specifically described with reference to FIG. The chemical liquid 4 stored in the chemical liquid tank 3 is supplied with nitrogen gas 20 from a nitrogen supply pipe 5 to pressurize the chemical liquid, and the chemical liquid is supplied to the hollow fiber membrane module 10 through the chemical liquid supply pipe 6 using the nitrogen gas pressure as a driving force. Supply to At this time, the valves 9 and 15 are opened, the valves 8 and 17 are closed, and the valve 16 is opened until the chemical starts flowing and the hollow fiber membrane module is filled.
Closes when the drug solution starts to flow from. In the hollow fiber membrane module, the chemical is supplied to the hollow portion of the hollow fiber membrane 11, the pressure outside the hollow fiber membrane is reduced to a pressure of 100 Pa to 10 KPa by the pressure reducing pump 13, and degassing is performed for a predetermined time. When the degassing is completed in this way, the valve 17 is opened, a new chemical is sent to the hollow fiber membrane module, and the degassed chemical is discharged from the chemical nozzle 19 to supply the degassed chemical to the use point. . In this example, the chemical solution is supplied to the outside of the hollow fiber membrane, but the chemical solution may be supplied to the hollow portion of the hollow fiber membrane for degassing.

[0043]

EXAMPLES Preparation of composite hollow fiber membranes, evaluation of gas permeation characteristics of the manufactured composite hollow fiber membranes, and results of chemical resistance test are described.

Example 1 Kraton G- as a styrene-based thermoplastic elastomer
1652 (trade name, manufactured by Shell Chemical) at 10% by weight and Clayton G-1657 (trade name, manufactured by Shell Chemical) at 8%
0% by weight, ENGAGE 84 as low density polyethylene
10 (trade name, manufactured by Dupont-Dow Elastomer Co., Ltd., density 0.870 g / cm ³ ) was weighed at 10% by weight and melt-blended with a twin-screw kneader. Then, the melt-blended polymer is supplied to the middle layer of the three-layer composite nozzle, and high-density polyethylene (B161, trade name, manufactured by Asahi Kasei Corporation) is supplied to the innermost layer and the outermost layer nozzle to perform three-layer composite spinning. A hollow fiber was obtained. This hollow fiber was annealed at 115 ° C. for 12 hours, stretched 1.3 times at room temperature, and subsequently stretched for 1 hour.
The film was stretched 5 times at 11 ° C. to obtain a three-layer composite hollow fiber membrane in which the innermost layer and the outermost layer were porous polyethylene, and the intermediate layer was a homogeneous thin film of a blend polymer of a styrene-based thermoplastic elastomer and a polyolefin. The dimensions of this hollow fiber membrane, porosity,
Table 2 shows the gas permeation characteristics and chemical resistance test results.

[0045]

[Table 2]

Example 2 Tefl at a resin temperature of 270 ° C. was applied to the intermediate layer of a three-layer composite nozzle.
on AF1600 (trade name, manufactured by DuPont, 2,2-
Bistrifluoromethyl-4,5-difluoro-1,3
A copolymer having a copolymerization ratio of dioxol and tetrafluoroethylene of 60/40 (mol%)) was supplied to the innermost layer and the outermost layer at a resin temperature of 270 ° C. and a poly (4
-Methylpentene-1) was supplied and melt-spinning was performed to obtain a three-layer composite hollow fiber. This hollow fiber is heated at 220 ° C. for 12 hours.
After annealing for a period of time, the film is stretched 1.3 times at room temperature, and then stretched 3 times at 111 ° C. The outermost layer is porous poly (4-methylpentene-1), and the intermediate layer is Tefl
On AF1600, a three-layer composite hollow fiber membrane that was a homogeneous thin film was obtained. Table 3 shows the dimensions, porosity, gas permeation characteristics, and chemical resistance test results of the hollow fiber membrane.

Example 3 A fluorine-based thermoplastic elastomer (Diel Thermoplastic T) was applied to the intermediate layer of a three-layer composite nozzle at a resin temperature of 200 ° C.
-630, trade name, manufactured by Daikin Industries, Ltd.)
The innermost layer and the outermost layer have a high stereoregular isotactic polypropylene (Hypol CJ700,
(Trade name, manufactured by Mitsui Chemicals, Inc.) and melt-spun to obtain a three-layer composite hollow fiber. 150 ° C
, And then stretched 1.3 times at room temperature, then stretched 3 times at 145 ° C. The innermost layer and the outermost layer are isotactic polypropylene, and the intermediate layer is a fluorine-based elastomer homogeneous film. A layer composite hollow fiber membrane was obtained. Table 3 shows the dimensions, porosity, gas permeation characteristics, and chemical resistance test results of the hollow fiber membrane.

Example 4 Low-crystalline poly (4-methylpentene-1) (MX001, trade name, manufactured by Mitsui Chemicals, Inc.) was supplied to the intermediate layer of a three-layer composite nozzle at a resin temperature of 250 ° C. The outermost layer has a high crystalline poly (4-methylpentene-
1) (RT-31, trade name, manufactured by Mitsui Chemicals, Inc.) was supplied and melt-spun to obtain a three-layer composite hollow fiber. This hollow fiber was annealed at 210 ° C. for 12 hours, stretched 1.3 times at room temperature, and stretched 5 times at 200 ° C., and the inner layer and the outer layer were made of porous poly (4-methylpentene).
1) A three-layer composite hollow fiber membrane in which the intermediate layer was a poly (4-methylpentene-1) homogeneous thin film was obtained. Table 3 shows the dimensions, porosity, gas permeation characteristics, and chemical resistance test results of the hollow fiber membrane.

Example 5 A polyolefin-based elastomer (Tuffmer XR106L, trade name, manufactured by Mitsui Chemicals, Inc.) was supplied to the intermediate layer of the three-layer composite nozzle at a resin temperature of 190 ° C., and the inner layer and the outer layer were heated at a resin temperature of 190 ° C. Stereoregular isotactic polypropylene (Hypol CJ700) was supplied and composite melt spinning was performed to obtain a three-layer composite hollow fiber. This hollow fiber is
After annealing at 0 ° C. for 12 hours, the film is stretched 1.3 times at room temperature, then stretched 3 times at 140 ° C., and the inner layer and the outer layer are made of porous isotactic polypropylene, and the intermediate layer is made of a polyolefin elastomer homogeneous thin film. A certain three-layer composite hollow fiber membrane was obtained. Table 3 shows the dimensions, porosity, gas permeation characteristics, and chemical resistance test results of the hollow fiber membrane.

[0050]

[Table 3]

Example 6 A hollow fiber membrane module (membrane area: 2.5 m ² ) was produced using the hollow fiber membrane produced in Example 1, and was attached to the chemical solution supply line shown in FIG. Open the valves 9, 15, and 16 and open the chemically amplified positive resist solution (AP
EX-E2405 (trade name, manufactured by Shipley Co.) was supplied to the hollow portion of the hollow fiber membrane of the hollow fiber membrane module 11 with 2 atm of nitrogen gas. After the hollow fiber membrane was filled with the chemical solution, the valve 16 was closed, and degassing was performed for 30 minutes while keeping the outside of the membrane at 100 Pa. The degassed resist solution was collected from the bypass pipe 14 of the chemical supply line, and the dissolved nitrogen concentration was measured.

Next, the valve 17 is opened, the degassed resist solution is dropped on the silicon wafer while supplying a new resist solution to the hollow fiber membrane module, and the dropped resist solution is shaken off at a rotation speed of the spin coater of 3000 rpm. Then, a resist thin film (having a thickness of 0.80 μm) was formed. After evaporating and drying the residual solvent in the resist thin film, the surface of the resist thin film was observed with a scanning electron microscope for a defect considered to be uneven due to bubbles in an area of 100 μm × 100 μm. Table 4 shows the evaluation results.

Example 7 The resist thin film obtained in Example 6 was pre-baked at 90 ° C. for 60 seconds, and then a photomask was overlaid on the resist film and subjected to close contact exposure with KrF excimer laser light.

A hollow fiber membrane module was fabricated using the hollow fiber membrane fabricated in Example 2 (membrane area: 2.5 m ² ), and this was developed by a coater developer for semiconductor manufacturing, which is the same chemical solution supply line as in FIG. Attach to a liquid supply line and use a 2 atmosphere nitrogen gas for a developer (MF-321, trade name, manufactured by Shipley Co., aqueous solution of tetramethylammonium hydroxide,
Flow rate of 1 L / mi
n, the solution is supplied to the hollow portion of the hollow fiber membrane, and the inside of the hollow fiber membrane is filled with the developing solution.
Degassed for 0 minutes.

After the completion of degassing, the degassed developing solution was dropped from the discharge nozzle onto the exposed surface, and development was performed. The deaerated developer was separated from the bypass pipe, and the dissolved nitrogen concentration was measured. The resist film obtained by this development treatment was after-baked in a dry oven at 120 ° C.
Observe the 00 μm area with a scanning electron microscope and check the groove width 2
1, a land width 22, a groove depth 23 (see FIG. 3), and defective portions during development were observed. Table 4 shows the evaluation results.

Example 8 A hollow fiber membrane module was produced using the hollow fiber membrane produced in Example 3 (membrane area 2.5 m ² ), and this was attached to the same chemical solution supply line as in FIG. Isopropyl alcohol was supplied to the hollow fiber membrane module by gas, and after the hollow portion of the hollow fiber membrane was filled with isopropyl alcohol, degassing was performed for 30 minutes while maintaining the outside of the hollow fiber membrane at 100 Pa.

After the completion of the degassing, fresh isopropyl alcohol was supplied to the membrane module, and the degassed isopropyl alcohol was dropped on the silicon wafer from the discharge nozzle to clean the silicon wafer. The deaerated isopropyl alcohol was separated from the bypass pipe, and the dissolved nitrogen concentration was measured. Table 4 shows the evaluation results.

Example 9 A module was produced using the hollow fiber membrane produced in Example 4 (membrane area 2.5 m ² ), and this was attached to the same chemical solution supply line as in FIG. A spin-on glass solution (composition: 70% by weight of isopropyl alcohol / 2% by weight of tetraethoxysilane / 28% by weight of water) is supplied to the hollow fiber membrane module, and after the hollow portion of the hollow fiber membrane is filled with the spin-on glass solution, the valve 2 Was closed, and the inside of the hollow fiber membrane was kept at 100 Pa and degassed for 30 minutes.

After the degassing, the degassed spin-on-glass solution was dropped onto the silicon wafer from the discharge nozzle to form an insulating film on the silicon wafer. The degassed spin-on-glass solution was separated from the bypass pipe, and the dissolved nitrogen concentration was measured. Further, the formed insulating film was placed in a dry oven at 150 ° C. to allow a condensation reaction to proceed. 100 on the insulating film surface
The area of μm × 100 μm was observed with a scanning electron microscope to see if there was any defect. Table 4 shows the evaluation results.

Example 10 A hollow fiber membrane module was produced using the hollow fiber membrane produced in Example 5 (membrane area: 2.5 m ² ), and five of them were connected in series. Attached to the chemical supply system shown. The ink for ink jet printer cartridge (solvent composition; water 80 wt%, ethylene glycol 5 wt%, isopropyl alcohol 15 wt% dye-based ink) is pressurized with air pressure of 2 atm at a flow rate of 100 mL / min into the hollow portion of the hollow fiber membrane. Supplied. Then, the outside of the hollow fiber membrane was degassed for 30 minutes while maintaining a reduced pressure of 100 Pa.

The degassed ink passed through the five modules was separated from the bypass pipe, and the dissolved oxygen and nitrogen concentrations in the ink were measured. Next, the degassed ink is filled from a nozzle into an ink cartridge container (the inside is kept at a reduced pressure of 100 Pa), and the cartridge is inserted into an ink jet printer (PM700C, trade name, manufactured by Seiko Epson Corporation).
And a printing test was conducted. The print missing frequency is shown as a relative ratio of the print missing dot area to the total print dot area. When the frequency of the print omission is smaller than 1%, the print omission is small, and high-quality printing is recognized by the naked eye. Table 4 shows the evaluation results.

[0062]

[Table 4]

Comparative Example 1 A hollow fiber membrane module was prepared by bundling 5000 polypropylene porous hollow fiber membranes (KPF190M, trade name, manufactured by Mitsubishi Rayon Co., Ltd.), and the same method as in Examples 6, 7, and 10 was used. Experiments were conducted to deaerate semiconductor resist, deaerate developer, and deaerate ink for inkjet printers. In each case, the chemical solution leaked from the pores of the membrane, and the degassing effect of the membrane was not obtained.

Comparative Example 2 Polytetrafluoroethylene tube membrane (Poeflon,
Trade name, Sumitomo Electric Chemical Co., Ltd., film thickness 50 μm) is 20
A membrane module was manufactured by bundling 0 pieces, and degassing for a developer, degassing for a semiconductor resist, and degassing for ink for an ink jet printer were performed in the same manner as in Examples 6 and 10. Was done. In each case, the chemical solution leaked from the pores of the membrane, and the degassing effect of the membrane was not obtained.

Reference Example 1 A three-layer composite hollow fiber membrane was prepared in the same manner as in Example 1, except that the thickness of the intermediate layer was changed to 20 μm. The oxygen permeation flow rate of this hollow fiber membrane is 4 × 10 ⁻¹⁰ cm ³ /
(Cm ² · Pa · sec), and the nitrogen permeation flow rate is 1.
It was 7 × 10 ⁻¹⁰ cm ³ / (cm ² · Pa · sec). 5000 hollow fiber membrane modules were produced by bundling 5000 three-layer composite hollow fiber membranes. The developing solution was degassed in the same manner as in Example 7, and 10% of the developing surface using this was used.
It was observed by a scanning electron microscope whether or not a defect occurred in the groove and land portions in the 0 μm × 100 μm region. A circular undeveloped portion having a radius of 0.5 μm was found in this region.
No degassing effect was observed by the membrane method.

Reference Example 2 A three-layer composite hollow fiber membrane (MHF200TL, trade name, manufactured by Mitsubishi Rayon Co., Ltd., manufactured by Mitsubishi Rayon Co., Ltd., having an inner diameter of 200 μm, a uniform membrane thickness of 1 μm, and a porous layer thickness of polyethylene) 25 μm) were bundled to form a hollow fiber membrane module, and isopropyl alcohol was degassed in the same manner as in Example 8. In this case, the homogeneous membrane was swollen by isopropyl alcohol, and the weight change rate of the hollow fiber membrane became 95%. Further, while the degassing process was continued, the homogeneous film was broken and the solution leaked out, so that degassing could not be performed.

[0067]

According to the present invention, the separation membrane can be produced at a lower cost than the conventional fluororesin tube membrane, and the membrane module price can be reduced. This makes it possible to reduce the running cost of the user. In addition, when it is installed in a semiconductor manufacturing apparatus or the like, since it is a hollow fiber membrane, it can be installed even in a narrow space, and is excellent in practicality.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a composite hollow fiber membrane for degassing a chemical solution of the present invention.

FIG. 2 is a view showing an example of an apparatus used for performing degassing of a chemical solution using the composite hollow fiber membrane for degassing a chemical solution of the present invention.

FIG. 3 is a schematic diagram showing a surface state of a resist film after development.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Porous support layer 2 Homogeneous thin film 3 Chemical tank 4 Chemical liquid 5 Nitrogen supply pipe 6 Chemical supply pipe 7, 14 Bypass pipe 8, 9, 15, 16, 17 Valve 10 Hollow fiber membrane module 11 Hollow fiber membrane 12 Deaeration port 13 Decompression pump 18 Degassed chemical supply pipe 19 Chemical discharge nozzle 20 Nitrogen gas 21 Groove width 22 Land width 23 Groove depth

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 71/36 B01D 71/36 F-term (Reference) 4D006 GA32 HA02 HA18 MA01 MA09 MA31 MB03 MB04 MB11 MC22X MC23X MC24X MC29 MC30X MC81 NA21 NA45 NA66 PC01 4D011 AA17 AC10

Claims (10)

[Claims] 1. A hollow fiber membrane having a composite structure in which a homogeneous thin film is sandwiched between polyolefin-based porous support layers, wherein the homogeneous thin film and the porous support layer are in contact with each other without bonding, and When the chemical solution is supplied to one side of the hollow fiber membrane and the opposite surface of the hollow fiber membrane is negatively pressured with respect to the chemical solution supply surface to degas dissolved gas in the chemical solution, the chemical solution does not leak from the negative pressure side membrane surface. Composite hollow fiber membrane for chemical solution deaeration. 2. The composite hollow fiber membrane for chemical solution degassing according to claim 1, wherein a weight change rate after immersion in the chemical solution according to JIS K7114 is within a range of 0 to + 30%. 3. The method according to claim 1, wherein a flow rate ratio of the oxygen permeation flow rate to the nitrogen permeation flow rate is 1.1 or more, and a change rate of the flow rate ratio after immersion in the chemical solution is within ± 10% according to JIS K7114. The composite hollow fiber membrane for degassing a drug solution according to claim 1 or 2. 4. A nitrogen permeation flow rate of 0.5 × 10 ⁻⁹ cm ³ /
(Cm ² · Pa · sec) or more, and the oxygen permeation flow rate is 0.6 × 10 ⁻⁹ cm ³ / (cm ² · Pa · sec) or more. The composite hollow fiber membrane for degassing a chemical solution according to the above. 5. The composite hollow fiber membrane for chemical solution degassing according to claim 1, wherein the homogeneous thin film is a mixture of a styrene-based thermoplastic elastomer and a polyolefin. 6. The method according to claim 1, wherein the homogeneous thin film is a copolymer of 2,2-bistrifluoromethyl-4,5-difluoro-1,3-dioxole and tetrafluoroethylene. 5. The composite hollow fiber membrane for degassing a drug solution according to 3 or 4. 7. The method according to claim 1, wherein the homogeneous thin film is a fluorine-based thermoplastic elastomer.
The composite hollow fiber membrane for degassing a chemical solution according to the above. 8. The degassing solution according to claim 1, wherein the homogeneous thin film is poly (4-methylpentene-1) or a 4-methylpentene-1 copolymer. Composite hollow fiber membrane. 9. The method according to claim 1, wherein the homogeneous thin film is a polyolefin-based thermoplastic elastomer.
Or the composite hollow fiber membrane for degassing a chemical solution according to 4. 10. The method according to claim 1, wherein the porous support layer is any one of polyethylene, polypropylene, poly (4-methylpentene-1), polyvinylidene fluoride and polyoxymethylene. The composite hollow fiber membrane for chemical solution degassing according to claim 1.