JP2012040537A - Filter device, and chemical coating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter device which can obtain appropriate replacement timing of a filter element.SOLUTION: The filter device includes a filter element having a filter membrane and a support material for supporting the filter membrane. At least one of the filter membrane and the support material contains a substance which alters a color according to the absorbed amount of a metal ion.

Description

  Embodiments described herein relate generally to a filter device and a chemical solution coating system.

  In a method for manufacturing a semiconductor device, a film to be processed is deposited on a semiconductor substrate, and the film to be processed is patterned into a desired pattern. Specifically, first, a photosensitive material called a resist is deposited on the film to be processed to form a resist film, and a predetermined region of the resist film is exposed to form a latent image on the resist film. Next, a development process is performed to remove an exposed portion or an unexposed portion of the resist film to form a resist pattern, and the processed film is dry etched using the resist pattern as an etching mask. Thereby, the film to be processed is patterned into a desired pattern.

  As the exposure light source, ultraviolet light such as KrF excimer laser or ArF excimer laser is used from the viewpoint of throughput. When exposure is performed with such an exposure light source, pattern defects in a film to be processed due to minute metal impurities contained in a resist chemical solution have become apparent as the required dimensions of the semiconductor device become finer.

  Metal impurities in the resist chemical solution are removed by a filter device installed in front of the coating device in the factory supply line. When the use period of the filter element in the filter device becomes long, the metal impurity removal performance by the filter element tends to deteriorate. Therefore, in order to prevent defects such as defective patterns due to deterioration of filter element removal performance when the filter element replacement cycle is set too long, or the cost is increased by setting the filter element replacement cycle too short. Therefore, a method for grasping an appropriate replacement timing of the filter element is desired.

JP 2004-37430 A

  One embodiment aims at providing a filter device which can grasp the suitable exchange timing of a filter element, for example.

  According to one embodiment, a filter element having a filter membrane and a support material that supports the filter membrane is provided, and at least one of the filter membrane and the support material is colored according to the amount of adsorption of metal ions. There is provided a filter device characterized in that it comprises a changing substance.

  According to another embodiment, the above-described filter device for removing metal impurities in the chemical solution, and a coating device for applying the chemical solution from which the metal impurities have been removed by the filter device to a substrate are provided. A chemical solution application system is provided.

The figure which shows the chemical | medical solution application system to which the filter apparatus which concerns on embodiment is applied. The figure which shows the structure of the filter apparatus which concerns on embodiment. The figure which shows the structure of the filter apparatus which concerns on embodiment.

  Hereinafter, a filter device according to an embodiment will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment.

(Embodiment)
A chemical solution coating system 100 to which the filter device 1 according to the embodiment is applied will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration of a chemical solution application system 100.

  The chemical solution application system 100 includes a chemical solution bottle 91, a sub tank 92, a filter device 1, a sub tank 93, a tube diaphragm pump 94, a valve 95, and an application device 96.

  In the chemical solution bottle 91, a resist chemical solution is stored. The resist chemical solution stored in the chemical solution bottle 91 is led out to the sub tank 92 when the tube diaphragm pump 94 is driven. The chemical solution bottle 91 has a pressurizing tube (not shown), and pressurizes the resist chemical solution stored in the chemical solution bottle 91 with an inert gas (for example, nitrogen gas) from the pressurizing tube. Thus, the resist chemical solution may be led out to the sub tank 92.

  The sub tank 92 guides the resist chemical solution derived from the chemical solution bottle 91 to the filter device 1 and senses that the chemical solution in the chemical solution bottle 91 has run out. When the sub-tank 92 senses that the chemical solution has run out, the sub-tank 92 notifies that the chemical solution has run out via a predetermined notification unit (for example, a lamp or buzzer).

  The filter device 1 removes metal impurities in the resist chemical solution guided from the sub tank 92. The filter device 1 guides the resist chemical from which the metal impurities are removed to the sub tank 93. The configuration within the filter device 1 will be described later.

  The sub tank 93 temporarily stores the resist chemical solution guided from the filter device 1, and then the resist chemical solution is sucked into the tube diaphragm pump 94.

  The tube diaphragm pump 94 sends out the resist chemical solution sucked from the sub tank 93 to the valve 95 side. The tube diaphragm pump 94 may be another type of pump as long as the resist chemical solution in the sub tank 93 can be sucked and sent to the valve 95 side.

  The valve 95 is an adjustment valve that can adjust the opening degree, and is adjusted to an opening degree that corresponds to the discharge amount of the resist chemical solution in the subsequent coating apparatus 96. The valve 95 guides the resist chemical solution fed from the tube diaphragm pump 94 to the coating device 96 at a flow rate corresponding to the adjusted opening degree.

  The coating device 96 has a stage 96b on which the semiconductor substrate WF is placed and supports the semiconductor substrate WF, and a nozzle for discharging the resist chemical solution fed from the tube diaphragm pump 94 through the valve 95 toward the semiconductor substrate WF. 96a. In the coating device 96, the resist solution is applied (spin coated) from the nozzle 96a toward the semiconductor substrate WF while the stage 96b supports the semiconductor substrate WF and the stage 96b and the semiconductor substrate WF are rotated. Thus, a resist chemical solution (photosensitive substance) is deposited on the film to be processed to form a resist film. The coating device 96 may apply the resist chemical solution on the semiconductor substrate WF by a method other than the spin coating method such as the slit nozzle method.

  Thereafter, the semiconductor substrate WF on which the resist film is formed is transported from the coating device 96 to an exposure device (not shown), and a predetermined region of the resist film is exposed by the exposure device to form a latent image on the resist film. Next, the semiconductor substrate WF having a latent image formed on the resist film is transported from the exposure apparatus to the developing apparatus, and the developing apparatus exposes the exposed portion of the resist film (when the resist is a positive type) or the unexposed portion (resist is a negative type). In this case, a resist pattern is formed by performing a development process for removing the above. Further, the semiconductor substrate WF on which the resist pattern is formed is transferred from the developing device to the etching device, and the film to be processed is dry-etched by the etching device using the resist pattern as an etching mask. Thereby, the film to be processed is patterned into a desired pattern.

  The above process is repeated each time a film to be processed is deposited on the semiconductor substrate WF. The process of depositing the film to be processed on the semiconductor substrate WF is performed after the dry etching is performed and then the semiconductor substrate WF is transferred to the film formation apparatus.

  The application example of the filter device 1 according to the embodiment is not limited to such a chemical solution application system 100, and is applicable to any system as long as it is necessary to remove metal impurities in the chemical solution. May be.

  Next, the filter device 1 according to the embodiment will be described with reference to FIGS. 2 and 3. FIG. 2A is a diagram illustrating an appearance of the filter device 1. FIG. 2B is a diagram illustrating a cross-sectional configuration of the filter device 1 in the vertical direction. FIG. 2C is a diagram showing a horizontal sectional configuration of the filter device 1. FIG. 3 is an enlarged view showing a cross-sectional configuration of the filter device 1 in the horizontal direction.

  The filter device 1 includes an introduction pipe 60, a filter cartridge 50, a discharge pipe 70, and a housing 10.

  The introduction pipe 60 communicates with a space 10 a between the outer peripheral surface 50 a of the filter cartridge 50 and the inner peripheral surface 10 b of the housing 10. The introduction pipe 60 introduces the resist chemical solution guided from the sub tank 92 into the space 10a.

  The filter cartridge 50 is detachably installed in the housing 10. The filter cartridge 50 is a unit for removing metal impurities in the resist chemical solution guided from the sub tank 92 (see FIG. 1). The filter cartridge 50 is replaced with a new one when the replacement timing is reached.

  Specifically, as shown in FIG. 2B, the filter cartridge 50 includes an outer cage 40, a filter element 20, an inner core cage 30, and a discharge port 50b.

  The outer cage 40 protects and holds the filter element 20 from the outside of the filter element 20. The outer cage 40 has, for example, a substantially cylindrical shape having a diameter larger than that of the inner core cage 30, and a plurality of holes 40 a (see FIG. 3) for allowing the resist chemical solution to pass to the filter element 20 side are formed on the side surfaces thereof. Yes.

  The filter element 20 is disposed in a substantially cylindrical space 40 c between the inner peripheral surface 40 b of the outer cage 40 and the outer peripheral surface 30 c of the inner core cage 30. The filter element 20 is, for example, a sheet-like member, and is disposed in the space 40c in a state of being folded into a pleat shape. The filter element 20 performs a filtering operation to remove metal impurities in the resist chemical solution that has passed through the hole 40a of the outer cage 40, and passes the resist chemical solution from which the metal impurities have been removed to the inner core cage 30 side.

  The inner core cage 30 protects and holds the filter element 20 from the inside of the filter element 20. The inner core cage 30 has, for example, a substantially cylindrical shape smaller in diameter than the outer cage 40, and a plurality of holes 30a (see FIG. 3) for allowing the resist chemical solution to pass through the inner space 30b are formed on the side surfaces thereof. Yes. The resist chemical solution from which metal impurities have been removed is introduced into the space 30b.

  The discharge port 50 b communicates with the space 30 b inside the inner core cage 30. The discharge port 50b discharges the resist chemical liquid, from which metal impurities are removed, led from the space 30b, to the discharge pipe 70.

  The discharge pipe 70 communicates with the discharge port 50 b of the filter cartridge 50. The discharge pipe 70 further discharges the resist chemical solution discharged from the discharge port 50b of the filter cartridge 50 to the sub tank 93 (see FIG. 1).

  The housing 10 is provided outside the filter cartridge 50. The housing 10 is also called a filter capsule. In the housing 10, a space 10 a is formed between the outer peripheral surface 50 a of the filter cartridge 50 and the inner peripheral surface 10 b of the housing 10 with the filter cartridge 50 installed.

  The housing 10 has a window 11 for observing the filter element 20 from the outside. As described above, the outer cage 40 disposed outside the filter element 20 has a plurality of holes 40a. Thereby, the filter element 20 can be observed from the outside through the window 11 and the hole 40a.

  The position where the window 11 is provided may be a side portion of the housing 10 or a bottom portion of the housing 10 as long as the filter element 20 can be observed from the outside. The upper part in the housing 10 may be sufficient.

  Next, the configuration of the filter element 20 will be described with reference to FIG.

  The filter element 20 includes a first support material 21, a second support material 22, and a filter membrane (filter membrane) 23. The filter element 20 has a structure in which both surfaces of the filter film 23 are sandwiched between the first support material 21 and the second support material 22 (that is, a composite film).

  The first support material 21 supports the outer surface of the filter membrane 23. The first support material 21 is formed of, for example, fibers such as nylon resin knitted in a coarse mesh shape. The roughness of the eyes in the first support material 21 is sufficient to support the filter film 23 and the color of the filter film 23 is visible from the outside of the first support material 21. The color of the first support material 21 is white or transparent.

  The second support material 22 supports the inner surface of the filter film 23. The second support material 22 is formed of, for example, a fiber such as nylon resin knitted in a coarse mesh shape. The roughness of the eyes in the second support material 22 is sufficient to support the filter membrane 23. The color of the second support material 22 is white or transparent.

  The filter film 23 is sandwiched between the first support material 21 and the second support material 22. The filter film 23 physically adsorbs metal impurities in the introduced resist chemical solution, thereby allowing the resist chemical solution from which the metal impurities have been removed to pass therethrough. The filter film 23 is formed of fibers such as fine glass fibers, for example. The fineness of the eyes in the filter film 23 is fine enough to remove metal impurities in the resist chemical solution. Further, the filter film 23 contains a substance whose color changes according to the amount of adsorption of metal ions (that is, the number of chemically adsorbed metal ions). For example, the surface of the fiber in the filter membrane 23 is coated with a substance whose color changes in accordance with the amount of adsorption of metal ions, in addition to being coated with nylon resin or the like. In the filter film 23, it is considered that the amount of chemical adsorption of metal ions (the number of chemically adsorbed metal ions) increases as the amount of physical adsorption of metal impurities increases.

このポルフィリンは、鉄イオンが配位結合していない状態で、濃緑色〜濃青色の物質である。ポルフィリンは、中心に鉄イオンが配位結合すると、赤色の物質である、下記の化２で表されるポルフィリン錯体になる。すなわち、ポルフィリンは、鉄イオンが配位結合することにより、濃緑色〜濃青色から、赤色へと変化する。

The substance whose color changes according to the amount of adsorption of metal ions includes, for example, a plurality of organic molecules having ionochromic properties. Such an organic molecule is an organic molecule whose color changes according to chemical adsorption (for example, coordination bond) of metal ions, and includes, for example, porphyrin represented by the following chemical formula 1.

This porphyrin is a dark green to deep blue substance in which iron ions are not coordinated. When an iron ion is coordinated to the center of porphyrin, it becomes a porphyrin complex represented by the following chemical formula 2, which is a red substance. That is, porphyrin changes from dark green to dark blue to red when iron ions are coordinated.

  Here, among the substances coated on the surface of the fiber in the filter membrane 23, since the nylon resin or the like is white or transparent, the filter membrane 23 in a state where no iron ions are adsorbed is, for example, light blue. The filter membrane 23 is light blue → light red → red as the adsorption amount of iron ions increases (as the number of porphyrin molecules that change to red due to coordination of iron ions in all porphyrin molecules increases). It will change.

  At this time, as described above, the coarseness of the fibers in the first support material 21 is such that the color of the filter film 23 is visually observable from the outside of the first support material 21. When viewed from the outside, the color of the filter film 23 can be confirmed from between the fibers in the first support material 21.

  That is, as described above, since the filter element 20 can be observed from the outside through the window 11 and the hole 40a, the color of the substance contained in the filter film 23 is externally input through the window 11 and the hole 40a. Can be observed. Further, as described above, in the filter film 23, it is considered that the chemical adsorption amount of metal ions (the number of chemically adsorbed metal ions) increases as the physical adsorption amount of metal impurities increases. By observing the color of the substance contained in the filter film 23 corresponding to the chemical adsorption amount of metal ions, it is possible to confirm the saturation of the physical adsorption amount of metal impurities, that is, the deterioration of the removal performance of the filter element 20. Is expected.

  Therefore, the present inventor evaluated the correlation between the color of the filter element 20 (the filter film 23 in the filter element 20) and the deterioration of the removal performance of the filter element 20 by using the filter device 1 according to the embodiment.

  The color of the filter element 20 changed from light blue to light red when the filter device 1 was used for 6 months. The color of the filter element 20 changed from light red to red when the filter device 1 was used for 8 months, and no further color change was observed.

  In parallel with the observation of the color of the filter element 20, the semiconductor device manufactured using the filter device 1 was inspected by an electrical characteristic inspection and an optical microscope. According to the defect trend data obtained in this way, after using the filter device 1 for 8 months, an increasing tendency of bridge defects (short defects) in the line pattern is confirmed, and deterioration of the removal performance of the filter element 20 is confirmed. It was done.

  Therefore, as a result of analyzing the filter membrane 23 of the filter element 20 after using the filter device 1 for 8 months, iron ions are coordinated to the porphyrin contained in the filter membrane 23, and an iron porphyrin complex is formed. It was confirmed that In other words, it was confirmed that the appropriate replacement timing of the filter element 20 is a timing (after about 8 months) when the filter element 20 changes to red and is fixed.

  Here, suppose that in the filter device 1, a case where the filter film 23 of the filter element 20 does not include a substance whose color changes according to the amount of adsorption of metal ions. In this case, since the deterioration of the removal performance of the filter element 20 cannot be grasped, it is difficult to grasp an appropriate replacement timing of the filter element.

  At this time, the point in time when a certain exchange period determined empirically has elapsed is used as the exchange timing. As a result, for example, when the replacement period (for example, one year) determined empirically by one standard filter device is applied to another filter device as it is, the removal performance of the filter element 20 is deteriorated. Therefore, it is possible to continue using another filter device for a predetermined period. As a result, defects such as pattern defects due to deterioration of the filter element removal performance tend to occur frequently. Alternatively, for example, a period excluding a margin period from the use period based on the use period of the case where the deterioration of the filter element removal performance among a plurality of filter devices is the fastest is an exchange period (for example, 4 months) When the filter element 20 is applied to each filter device, the filter element 20 is frequently replaced even though the removal performance of the filter element 20 is not deteriorated. As a result, the operation cost of the filter device tends to increase.

  On the other hand, in the embodiment, in the filter device 1, the filter film 23 of the filter element 20 includes a substance whose color changes according to the amount of adsorption of metal ions. Accordingly, by observing the color change of the filter element 20, it is possible to grasp the deterioration of the removal performance of the filter element 20, and therefore it is possible to grasp the appropriate replacement timing of the filter element 20.

  As a result, it is possible to avoid the supply of the resist chemical solution containing metal impurities to the coating device 96, so that the coating device 96 can reliably apply the resist chemical solution from which the metal impurities have been removed onto the semiconductor substrate WF. .

  In particular, a substance whose color changes in accordance with the amount of adsorption of metal ions includes a plurality of organic molecules having ionochromic properties. Thereby, a substance whose color changes in accordance with the adsorption amount of metal ions can be easily included in the filter film 23 of the filter element 20. For example, by coating the surface of the fiber in the filter membrane 23, the filter membrane 23 of the filter element 20 can be easily included.

  Specifically, the substance whose color changes according to the amount of adsorption of metal ions includes a plurality of porphyrins. The filter membrane 23 of the filter element 20 is light blue → light red → as the iron ion adsorption amount increases (as the number of porphyrin molecules that change to red due to coordination of iron ions in all porphyrin molecules increases). It will change to red. That is, the substance contained in the filter film 23 is a substance in which the color change of the filter element 20 can be easily observed.

  Alternatively, in the filter device 1, in order to grasp the deterioration of the removal performance of the filter element 20, a measuring instrument is provided in the space 30 b inside the inner core cage 30 or the discharge pipe 70 to measure the concentration of metal ions. Think about the case. In this case, in addition to the measuring device, a member for holding the measuring device is required, and further, wiring for taking out a measurement value obtained by the measuring device is also required. Thereby, since the structure of the filter apparatus 1 becomes complicated, it exists in the tendency for the manufacturing cost of the filter apparatus 1 to increase.

  On the other hand, in the embodiment, the housing 10 has a window 11 for observing the filter element 20 from the outside. Thereby, since the filter element 20 can be observed from the outside through the window 11 and the hole 40a, the color of the substance contained in the filter film 23 can be observed from the outside through the window 11 and the hole 40a. it can. As a result, it is possible to grasp the deterioration of the removal performance of the filter element 20 without complicating the configuration of the filter device 1. That is, since it is possible to avoid making the configuration of the filter device 1 complicated, an increase in the manufacturing cost of the filter device 1 can be suppressed.

  In the filter element 20, the first support material 21 may be included instead of the filter film 23 that contains a substance whose color changes according to the amount of adsorption of metal ions. Alternatively, the filter element 20 may include both the first support material 21 and the filter film 23 that contain a substance whose color changes according to the amount of adsorption of metal ions.

  The substance whose color changes according to the amount of adsorption of metal ions may include a plurality of organic molecules of porphyrin derivatives other than porphyrin. The porphyrin derivative may be, for example, aminoporphyrin, porphyrin sulfonic acid, porphyrin-based dye, and the like.

このフタロシアニンは、マグネシウムイオンが配位結合していない状態で、青色の物質である。フタロシアニンは、中心にマグネシウムイオンが配位結合すると、緑色の物質である、下記の化４で表されるフタロシアニン錯体になる。すなわち、フタロシアニンは、マグネシウムイオンが配位結合することにより、青色から、緑色へと変化する。

この場合、フィルター膜２３は、マグネシウムイオンの吸着量が増えるに従って（フタロシアニンの全分子におけるマグネシウムイオンが配位結合して緑色へ変化するフタロシアニンの分子数が増えるに従って）、薄青色→薄緑色→緑色と変化していく。 Alternatively, the substance whose color changes in accordance with the amount of adsorption of metal ions may include phthalocyanine or a phthalocyanine derivative represented by the following chemical formula 3 instead of porphyrin or a porphyrin derivative. The phthalocyanine derivative may be a phthalocyanine dye.

This phthalocyanine is a blue substance in a state where magnesium ions are not coordinated. When a magnesium ion is coordinated to the center of phthalocyanine, it becomes a phthalocyanine complex represented by the following chemical formula 4, which is a green substance. That is, phthalocyanine changes from blue to green when magnesium ions are coordinated.

In this case, the filter film 23 becomes light blue → light green → green as the adsorption amount of magnesium ions increases (as the number of phthalocyanine molecules that change to green due to coordination of magnesium ions in all molecules of phthalocyanine increases). And change.

  Alternatively, the substance whose color changes according to the amount of metal ion adsorption may include both porphyrin (derivative) and phthalocyanine (derivative). In this case, for example, the member (at least one of the first support material 21 and the filter film 23) containing the substance in the filter element 20 includes the first portion containing porphyrin (derivative) and the phthalocyanine (derivative). ) May be included. In this case, it is possible to grasp the deterioration of the removal performance of the filter element 20 in consideration of both the color change of the first part (blue → red) and the color change of the second part (blue → green). .

この化５で表される有機分子は、マグネシウムイオンが包摂されていない状態で、青色の物質である。化５で表される有機分子は、マグネシウムイオンがエーテル結合部（−Ｏ−Ｏ−Ｏ−Ｏ−）で包摂されると、緑色の物質である、下記の化６で表される有機分子になる。すなわち、化５で表される有機分子は、マグネシウムイオンが包摂されることにより、青色から、緑色へと変化する。

この場合、フィルター膜２３は、マグネシウムイオンの吸着量が増えるに従って（化５で表される有機物の全分子におけるマグネシウムイオンが配位結合して緑色へ変化する化５で表される有機物の分子数が増えるに従って）、薄青色→薄緑色→緑色と変化していく。 Alternatively, the substance whose color changes depending on the amount of adsorption of metal ions is 4,4 ′-[(ethylenedioxy) bis (ethyleneoxy)] bis [1- (2-imidazo) represented by the following chemical formula 5. [4,5-f] -1,10-phenanthroline) benzene].

The organic molecule represented by the chemical formula 5 is a blue substance in a state where magnesium ions are not included. The organic molecule represented by Chemical Formula 5 is a green substance that is a green substance when magnesium ions are included in the ether bond (—O—O—O—O—). Become. That is, the organic molecule represented by Chemical formula 5 changes from blue to green by inclusion of magnesium ions.

In this case, the filter film 23 increases the number of adsorbed magnesium ions. As the number increases, the color changes from light blue to light green to green.

  Further, the metal ion to be adsorbed by organic molecules may be a metal ion other than iron ions or magnesium ions.

  For example, in the case where the filter membrane 23 contains diphenyl caldibad, as the adsorbed amount of cadmium ions increases (diphenyl cardibad that changes to red due to coordination of cadmium ions in all molecules of diphenyl cardibad). As the number of molecules increases, the color changes from white to light red to red.

  For example, when diphenyldithiocaldibad is contained in the filter membrane 23, diphenyl which changes to reddish brown as the bismuth ion adsorption amount increases (bismuth ions in all molecules of diphenyldithiocaldibad are coordinated and bonded. As the number of dithiocaldibad molecules increases), it changes from gray to light reddish brown to reddish brown.

  For example, when pyrogallol red is contained in the filter membrane 23, as the adsorption amount of antimony ions increases (the number of pyrogallol red molecules in which antimony ions in all the pyrogallol red molecules are coordinated and changed to red brown increases. To light brown → light red brown → red brown.

  For example, when dithizone is contained in the filter membrane 23, as the amount of adsorption of lead ions increases (as the number of dithizone molecules in which all the molecules of dithizone coordinate and bond to orange and change to orange), It changes from white to light orange to orange.

  For example, when tetraphenylporphine tetrasulfonic acid is contained in the filter membrane 23, the cadmium ion adsorption amount increases (cadmium ions in all the molecules of tetraphenylporphine tetrasulfonic acid are coordinated and change to green. As the number of molecules of tetraphenylporphine tetrasulfonic acid increases, the color changes from light yellow to light green to green.

  For example, when α, β, γ, δ-tetrakismethylpyridylporphine is contained in the filter membrane 23, as the amount of mercury ion adsorption increases (in all molecules of α, β, γ, δ-tetrakismethylpyridylporphine). As the number of molecules of α, β, γ, δ-tetrakismethylpyridyl porphine in which mercury ions are coordinated and change to orange increases), the color changes from light green to light orange to orange.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 Filter apparatus, 10 Housing, 10a space, 10b Inner peripheral surface, 11 Window, 20 Filter element, 21 1st support material, 22 2nd support material, 23 Filter membrane, 30 Inner core cage, 30a hole, 30b space , 30c outer peripheral surface, 40 outer cage, 40a hole, 40b inner peripheral surface, 40c space, 50 filter cartridge, 50a outer peripheral surface, 50b discharge port, 60 introduction pipe, 70 discharge pipe.

Claims (5)

A filter element having a filter membrane and a support material that supports the filter membrane,
At least one of the filter film and the support material contains a substance whose color changes in accordance with the amount of adsorption of metal ions. The filter device according to claim 1, wherein the substance includes a plurality of organic molecules having ionochromic properties. The filter device according to claim 2, wherein the organic molecule includes at least one of porphyrin, phthalocyanine, and derivatives thereof. A housing provided outside the filter element;
The filter device according to any one of claims 1 to 3, wherein the housing has a window for observing the color of the substance from the outside. The filter device according to any one of claims 1 to 4, for removing metal impurities in the chemical solution;
A coating apparatus for applying a chemical solution from which metal impurities have been removed by the filter device on a substrate;
A chemical application system characterized by comprising:

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