KR100858047B1 - An apparatus and method for recovering solvent - Google Patents

Abstract

It is an object of the present invention to provide a solvent recovery apparatus and a solvent recovery method capable of recovering a high concentration of solvent from waste liquid discharged from a resist stripping step without replenishing an electronic grade solvent.

To this end, the solvent recovery device 1 of the present invention is a device for recovering the solvent from the waste liquid L discharged in the resist stripping step, and a resin component removal device for removing the resin component contained in the waste liquid L ( 10), the first distillation column 20 for removing the low boiling point impurities contained in the waste liquid (L), the second distillation column (30) for removing the high boiling point impurities contained in the waste liquid (L), and the first One or both of the distillation column 20 and the second distillation column 30 is provided with a solvent storage tank 51 for replenishing the industrial grade solvent L7.

Solvent recovery apparatus, resin component removal means, solvent component purification means, solvent component replenishment means

Description

Solvent recovery apparatus and solvent recovery method {AN APPARATUS AND METHOD FOR RECOVERING SOLVENT}

1 is a flowchart of a solvent recovery method according to the embodiment.

2 is an overall configuration diagram of a solvent recovery device.

It is a figure which shows the internal structure of a resin component removal apparatus.

[Description of the code]

1 solvent recovery apparatus 2 waste liquid storage tank

4 resin component storage tank 10 resin component removal device

18 rotating body 19 brush

19a motor 20 1st distillation column

29 Low boiling impurity storage tank 30 Second distillation column

39a first collection liquid tank 39b second collection liquid tank

41 filter 42a solvent concentration detection means

42b solvent concentration detection means 42c impurity concentration detection means

43 Vacuum pumps 50 Solvent components Purification means

51 Solvent Storage Tank 60 Solvent Ingredient Supplement

The present invention relates to a solvent recovery apparatus and a solvent recovery method. More specifically, the present invention relates to an apparatus and a method for recovering a solvent from waste liquid discharged from a resist stripping step of a liquid crystal or a semiconductor manufacturing plant.

In the peeling process of a resist layer in a semiconductor factory or a liquid crystal monitor factory, monoethanolamine (hereinafter abbreviated as MEA) and dimethyl sulfoxide (hereinafter abbreviated as DMSO) as a peeling liquid of the resist resin are in a predetermined ratio. A mixed solvent and a solvent in which MEA and diethylene glycol monobutyl ether (hereinafter abbreviated as BDG) are mixed at a predetermined ratio are used. Moreover, it is called thinner which mixed propylene glycol monomethyl ether acetate (it abbreviates as PGMEA hereafter) and propylene glycol monomethyl ether (hereinafter abbreviated as PGME) as a solvent for washing a liquid crystal or a semiconductor substrate. Solvent is used. These solvents used in the resist stripping process are discharged as waste liquids containing various impurities such as resist resin, water, heavy metals and fine particles. Although the discharged waste liquid is usually disposed of in disposal, it is expected that the above-mentioned solvent will be recovered and reused for reasons such as high cost and high use of the solvent.

Here, the solvent regeneration apparatus of patent document 1 is known as an apparatus for collect | recovering a solvent from the waste liquid of a resist peeling process conventionally. According to the solvent regeneration apparatus of patent document 1, while removing a resist resin from the waste liquid discharged at the resist stripping process, impurities, such as water and heavy metals contained in waste liquid, can be removed. Thereby, the peeling liquid comprised by mixing MEA and DMSO, or the peeling liquid comprised by mixing MEA and BDG can be collect | recovered from waste liquid. Moreover, the thinner comprised by mixing PGMEA and PGME can be collect | recovered from waste liquid.

However, in the above-described conventional solvent regeneration apparatus, not only low-boiling impurities but also solvent components in the waste liquid are removed from the top of the distillation column tower for removing impurities from the waste liquid by the evaporation. In addition, the solvent component is separated as a high boiling point impurity from the distillation column for removing the high boiling point impurity by the reaction with polymerization by heat. Therefore, the concentration of the solvent recovered from the waste liquid is lower than that used in the resist stripping step. Moreover, the solvent comprised from multiple components may change a component ratio by reaction, such as carbonate. For this reason, when reusing the solvent recovered from the waste liquid, it is necessary to adjust it to the concentration which can supplement and reuse the refined solvent with high purity. In this case, since a highly purified solvent (an electronic grade solvent) must be replenished, there is a problem that the cost for procuring this electronic grade solvent becomes high.

In addition, in the peeling process of a resist, in the case of conveyance of a board | substrate or a silicon wafer, it is usual that a small amount of peeling liquid disappears by accompanying with such a board | substrate or a silicon wafer. Further, in the step of recovering the solvent component as the stripping liquid from the waste liquid, it is usual that the solvent component in the waste liquid is volatilized from the top of the distillation column to the atmosphere and disappears in small amounts. Therefore, since the peeling liquid used at the resist peeling process is not enough only by the peeling liquid collect | recovered at the recovery process, you must purchase a new peeling liquid and make up for the shortfall. In this case, there exists a problem that the cost for procuring the peeling liquid for replenishment becomes high.

[Patent Document 1] Japanese Patent No. 3409028

An object of the present invention is to provide a solvent recovery apparatus and a solvent recovery method capable of recovering a high concentration of solvent from the waste liquid discharged from the resist stripping step and not having to replenish an electronic grade solvent.

Means for solving the problems are inventions as described below.

(1) An apparatus for recovering a solvent from waste liquid discharged from a resist stripping process:

Resin component removing means for removing the resin component contained in the waste liquid;

Solvent component purifying means for purifying the solvent component contained in the waste liquid; And

And a solvent component replenishing means for replenishing the solvent component in the waste liquid supplied to the solvent component refining means.

(2) The solvent recovery device according to the above (1),

The solvent component purifying means is constituted by a first distillation column for removing low-boiling impurities having a lower boiling point than the solvent component in the waste liquid, and a second distillation column for removing high-boiling impurities having a higher boiling point than the solvent component in the waste liquid. ,

And the solvent component replenishing means replenishes the solvent component in at least one of the first and second distillation columns.

(3) The solvent recovery device according to the above (2),

And said solvent component replenishing means replenishes an industrial grade solvent in at least one of said first distillation column and said second distillation column.

(4) The solvent recovery device according to the above (3),

Impurity concentration detection means for detecting the concentration of impurities contained in the industrial grade solvent,

And the solvent component replenishing means changes the replenishment of the industrial grade solvent between the first distillation column and the second distillation column on the basis of the detection value by the impurity concentration detecting means.

(5) The solvent recovery device according to any one of (1) to (4),

A solvent concentration detection means is provided at the rear end of the solvent component purification means, detects the solvent concentration at the rear end of the solvent component purification means, adjusts the replenishment amount of the solvent component by the solvent component replenishment means, and the solvent component. A solvent recovery apparatus, wherein the solvent concentration at the rear end of the purification means is maintained within a predetermined concentration range.

(6) The solvent recovery apparatus as described in any one of said (1)-(5),

The solvent recovery apparatus of the said waste liquid is a peeling liquid of a resist.

(7) The solvent recovery apparatus as described in any one of said (1)-(5),

A solvent recovery device, characterized in that the solvent component in the waste liquid is thinner.

(8) The solvent recovery apparatus as described in any one of said (1)-(5),

The resin component removal means is a resin component removal device comprising an airtight cylindrical body having an inner circumferential surface as a heatable evaporation surface, and a rotating body disposed in the cylindrical body and radially having a brush on its outer circumferential surface. Recovery device.

(9) A method for recovering a solvent from waste liquid discharged from a resist stripping step:

A resin component removing step of removing the resin component contained in the waste liquid;

A solvent component purification step of purifying the solvent component contained in the waste liquid; And

And a solvent component replenishing step of replenishing the solvent component in the waste liquid supplied to the solvent component refining process.

(10) As a solvent recovery method as described in said (9),

The solvent component purification step includes a step of removing a low boiling point impurity having a lower boiling point than the solvent component in the waste liquid by a first distillation column, and a high boiling point impurity having a higher boiling point than the solvent component in the waste liquid by a second distillation column. Has a process of removing,

In the solvent component refilling step, a solvent component is replenished in at least one of the distillation column of the first distillation column and the second distillation column.

(11) As a solvent recovery method as described in said (10),

In the solvent component replenishing step, a solvent recovery method comprising replenishing an industrial grade solvent to at least one of the first and second distillation columns.

(12) The solvent recovery method according to any one of the above (9) to (11),

A solvent concentration detection means is provided at the rear end of the solvent component purification means, the solvent concentration at the rear end of the solvent component purification means is detected, the replenishment amount of the solvent component by the solvent component replenishment means is adjusted, and the solvent component purification is performed. A solvent recovery method characterized by maintaining the solvent concentration at the rear end of the means within a predetermined concentration range.

(13) As a solvent recovery method in any one of said (9)-(12),

The solvent recovery method of the said waste liquid is a peeling liquid of a resist.

(14) As a solvent recovery method in any one of said (9)-(12),

A solvent recovery method, characterized in that the solvent component in the waste liquid is thinner.

As the "solvent" in the present invention, various solvents used in the resist stripping step, for example, a stripping solution for removing the resist, a thinner used for cleaning the substrate, and the like are indicated. As a peeling liquid of a resist, the solvent etc. which mixed MEA and DMSO, or MEA and BDG in predetermined ratio can be used, for example. As the thinner for cleaning the substrate, for example, a solvent in which PGMEA and PGME are mixed can be used.

The "low boiling point impurity" in the present invention is an impurity having a boiling point lower than that of the solvent component, and is typically water contained in the waste liquid. In addition, as a "high boiling point impurity" in this invention, it is an impurity which has a boiling point higher than a solvent component.

As the "resin component removing means" in the present invention, the overall apparatus capable of removing the resin component dissolved or liberated in the waste liquid is indicated. As such an apparatus, for example, an apparatus for separating only the nonvolatile components represented by the resin component by bringing the waste liquid into contact with the heated metal surface can be used. For example, a closed cylindrical body having an inner circumferential surface as a heatable evaporation surface, and a rotating body disposed in the cylindrical body and having a brush radially on the outer circumferential surface thereof, the waste liquid is supplied between the evaporating surface and the rotating body. By contacting the heated evaporation surface with the waste liquid, a falling film type evaporation separation apparatus capable of evaporating the low boiling point impurity and the solvent component in the waste liquid and allowing the resin component to flow down can be used.

As a "solvent component purification means" in this invention, the whole apparatus which can refine | purify the solvent component in a waste liquid is indicated. As such an apparatus, a distillation column, a rectifying column, an evaporation can, or the like can be used. As the distillation column, for example, a multi-stage distillation column in which a plurality of trays are arranged inside the tower may be used, or a distillation column in which packings such as raschig rings are filled in the tower may be used.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail, referring drawings.

In this embodiment, the apparatus and method for recovering a solvent from the waste liquid discharged | emitted at the resist stripping process at the time of manufacturing a semiconductor or a liquid crystal display are demonstrated. In addition to the solvent component, the waste liquid discharged from the resist stripping step contains impurities such as resist resin, water, reaction products, heavy metals, and fine particles.

1 is a flowchart of a solvent recovery method according to the present embodiment.

As shown in FIG. 1, in this embodiment, the resin component is removed from the waste liquid discharged | emitted at the resist stripping process (resin component removal process), and the solvent component of the waste liquid from which the resin component was removed after that is refine | purified (solvent component Purification process). Thereby, the high concentration solvent component from which the resin component and various impurities were removed from the waste liquid of a resist peeling process can be collect | recovered.

As shown in Fig. 1, the solvent component purification step of purifying the solvent component in the waste liquid includes a step of removing low-boiling impurities such as water from the waste liquid from which the resin component has been removed (low boiling point impurity removal step), and a waste liquid from which the resin component has been removed. It consists of two processes of removing heavy metals and other high boiling point impurities from the process (high boiling point impurity removal process).

In a resin component removal process, the resist resin melt | dissolved or liberated in the waste liquid is removed by peeling with a solvent. As described above, the resin component removal step is disposed on the front end side of the solvent component purification step so that the nonvolatile resist resin can be first removed from the waste liquid. For this reason, clogging etc. can be prevented in an apparatus by a resist resin being liberated in waste liquid in a process of a subsequent step.

In order to remove the resin component from the waste liquid, an evaporation separation apparatus for removing the resin component by evaporating the waste liquid, for example, an evaporation can or a disk dryer, can be used. Moreover, the apparatus which isolate | separates a resin component by making a waste liquid contact the heated metal surface can be used. For example, a closed cylindrical body having an inner circumferential surface as a heatable evaporation surface, and a rotating body disposed in the cylindrical body and having a brush radially on the outer circumferential surface thereof, the waste liquid is supplied between the evaporating surface and the rotating body. By contacting the waste liquid to the heated evaporation surface, the volatile components (low-boiling impurities, solvent components and some high-boiling impurities) in the waste liquid are evaporated, and the resin component in the waste liquid can be separated by falling. A falling film type evaporation separator can be used. By using the falling film type evaporation separation apparatus, the resist resin contained in the waste liquid can be almost completely removed.

In the low boiling point impurity removal process, the low boiling point impurity which has a boiling point lower than the solvent component in the waste liquid is removed from the waste liquid from which the resin component was removed in the above-mentioned resin component removal process. As said "low boiling point impurity", it is water etc. which are contained in waste liquid, for example.

In order to remove low boiling point impurities from the waste liquid, a distillation column can be preferably used. The distillation column may be a multi-stage distillation column in which a plurality of trays are arranged inside the tower, or may be a distillation column in which fillers such as lashing rings are filled in the tower. Moreover, the distillation column which combines the part of a tray of a multistage type | mold, and the part in which a packing material is filled up and down may be sufficient. By supplying the waste liquid from which the resin component has been removed to the distillation column, a condensate containing low boiling point impurities such as water can be obtained from the top of the column. Moreover, the waste liquid from which the resin component and the low boiling point impurity were removed can be obtained from the bottom part of a distillation column.

By the way, when MEA etc. are used as a solvent for peeling a resist resin, this MEA may absorb carbon dioxide etc. in air | atmosphere, and may form various salts (carbonates). In this embodiment, in the low-boiling-point impurity removal process mentioned above, not only low-boiling-point impurities, such as water, but also gas components, such as carbon dioxide dissolved in waste liquid, can be removed. Therefore, it is possible to prevent the formation of various salts in the waste liquid. In this case, the purity of the solvent component is improved, and in the apparatus at a later stage, salts can be precipitated in the waste liquid to prevent clogging and the like.

In the high boiling point impurity removal process, the high boiling point impurity which has a boiling point higher than the solvent component in the waste liquid is removed from the waste liquid from which the resin component was removed in the above-mentioned resin component removal process. In this high boiling point impurity removal step, heavy metals such as sodium, magnesium, manganese, copper, iron and the like dissolved in the waste liquid can also be removed.

In order to remove high boiling point impurities from the waste liquid, a distillation column can be preferably used. The distillation column may be a multi-stage distillation column in which a plurality of trays are arranged inside the tower, or may be a distillation column in which fillers such as lashing rings are filled in the tower. Moreover, the distillation column which combines the part of a tray of a multistage type | mold, and the part in which a packing material is filled up and down may be sufficient. By supplying the waste liquid from which the resin component has been removed to the distillation column, the waste liquid from which the resin component and the high boiling point impurities have been removed, that is, the purified solvent component after the removal of various impurities can be recovered from the top of the column. In addition, a residual liquid containing high boiling point impurities can be obtained from the bottom of the distillation column.

Generally, in the peeling process of the resist in a liquid crystal or a semiconductor manufacturing plant, it is usual for the peeling liquid which is MEA and DMSO, or a mixture of MEA and BDG to accompany a board | substrate or a silicon wafer, and is lost little by little. In the process of recovering the solvent from the waste liquid, the solvent component in the waste liquid is usually volatilized in the air from the top of the distillation column or the like and is lost little by little. Therefore, since only the recycled stripping solution is reused, the stripping solution used in the resist stripping step is insufficient, so a new stripping solution must be purchased and replenished. In this case, there exists a problem that cost becomes high in order to procure expensive peeling liquid.

In addition, in the recovery step of the stripping solution, since the solvent component in the stripping solution is lost little by little, there is a problem that the recovered stripping solution causes a difference in the mixing ratio of the solvent as compared with the new stripping solution. For this reason, in the solvent recovery method in the prior art, it was necessary to replenish the solvent component of which concentration was low with respect to the recovery liquid obtained by refine | purifying the solvent component in waste liquid, and to adjust a mixing ratio. In this case, there exists a problem that the cost for procuring the commercially available electronic grade solvent (single component solvent) refine | purified with high purity becomes high.

According to the solvent collection method in this embodiment, such a problem is solved. That is, in the solvent recovery method in the present embodiment, as shown in the flowchart of FIG. 1, the "liquid-grade solvent" is not replenished with the solvent recovered from the waste liquid, but the waste liquid supplied to the solvent component refining process, that is, The general "industrial grade solvent" is replenished with respect to the waste liquid refine | purified from this in a solvent component purification process. As a result, not only the solvent component contained in the waste liquid, but also the replenished industrial grade solvent is purified in the solvent component purification step. Therefore, a solvent having a high concentration that can be reused in the resist stripping step can be recovered without replenishing the electronic grade solvent. According to this method, it is only necessary to replenish the industrial grade solvent, so that the procurement of the electronic grade solvent and the new release liquid is unnecessary, and the solvent can be reused at a lower cost than the conventional method.

In addition, in order to replenish the industrial grade solvent to the waste liquid supplied to the solvent component refining process, only the industrial grade solvent may be replenished to the waste liquid supplied to the low boiling point impurity removal process, and only the industrial grade solvent may be supplied to the waste liquid supplied to the high boiling point impurity removal process. You may supplement. In addition, as shown in the flowchart of FIG. 1, an industrial grade solvent may be replenished with the waste liquid supplied to each of the low boiling point impurity removal process and the high boiling point impurity removal process.

Embodiments of the present invention will be described in detail with reference to the drawings.

2 is an overall configuration diagram of the solvent recovery device 1. As shown in FIG. 2, the solvent recovery apparatus 1 in this embodiment is a resin component removal apparatus 10 which removes a resin component from the waste liquid discharged | emitted at the resist stripping process, and low boiling point impurity from the waste liquid from which the resin component was removed. And a first distillation column 20 (low boiling point impurity removing means) for removing the oil, and a second distillation column 30 (high boiling point impurity removing means) for removing the high boiling point impurities from the waste liquid from which the resin component is removed. Although the 1st distillation column 20 and the 2nd distillation column 30 were combined, it corresponds to the solvent component purification means 50 in this invention.

The waste liquid L discharged from a resist stripping process such as a liquid crystal or a semiconductor manufacturing factory is once stored in the waste liquid storage tank 2. The waste liquid L stored in the waste liquid storage tank 2 is pumped by the pump 3 and supplied to the resin component removal apparatus 10.

3 is a diagram illustrating an internal structure of the resin component removing device 10. As shown in FIG. 3, the resin component removal apparatus 10 is arrange | positioned in the sealed cylinder body 11 which has the inner peripheral surface as the heat-evaporable evaporation surface 17, and the said cylinder body 11, and radially on the outer peripheral surface. It is a film-type evaporation separation apparatus provided with the rotating body 18 which has the brush 19. A hollow jacket portion 16 is formed around the cylinder body 11, and a supply port 16a capable of supplying steam to the jacket portion 16, and a steam outlet from the jacket portion 16. A discharge opening 16b is formed. The vaporization surface 17 is heated by supplying steam to the jacket part 16 from the said supply port 16a.

The waste liquid L supplied to the resin component removing device 10 flows down on the rotating disc, flows in a radial direction almost uniformly by centrifugal force, and is supplied between the evaporation surface 17 and the brush 19. When the waste liquid L comes into contact with the evaporation surface 17, the glass or dissolved resin component in the waste liquid L flows downward on the evaporation surface 17, and components other than the resin component are evaporated to vaporize. It discharges from the discharge port 18a. Thereby, the resin component and other components in waste liquid L are isolate | separated. The rotating body 18 provided coaxially with respect to the cylinder body 11 is rotated by the motor 19a, and the separation | separation of a resin component is promoted by the brush 19 provided radially in the outer periphery of this rotating body 18. FIG. .

The resin component separated from the waste liquid L is discharged to the resin component storage tank 4 through the pipe 16c provided in the lower part of the resin component removal apparatus 10. On the other hand, the waste liquid L1 from which the resin component has been removed is supplied to the stop portion of the first distillation column 20 through the pipe 5.

By supplying the waste liquid L1 to the stop portion of the first distillation column 20, the low boiling point impurities in the waste liquid L1 are removed.

That is, the first distillation column 20 is a packed distillation column, and the packing 20a is filled at the upper end side, and the packing 20b is filled at the lower end side. When the waste liquid L1 is supplied to the stop portion of the first distillation column 20, the waste liquid L2 containing a lot of low boiling point impurities, that is, water, can be obtained from the top of the column of the first distillation column 20. The waste liquid L3 from which the low boiling point impurity (moisture) was removed can be obtained from the bottom of the top of the first distillation column 20.

The waste liquid L2 containing a lot of low boiling point impurities (water) is discharged from the steam outlet 22 formed at the top of the column of the first distillation column 20. The waste liquid L2 discharged from the steam outlet 22 is liquefied by the first condenser 24 and the first vent condenser 25 and then stored in the reflux tank 26. A part of the waste liquid L2 stored in the reflux tank 26 is conveyed to the first distillation column 20 through the pipe 28 and stored in the low boiling point impurity storage tank 29 through the pipe 27. The reflux ratio at this time is appropriately determined while monitoring the moisture concentration and the like of the waste liquid L3 obtained from the bottom of the column.

The waste liquid L3 from which the low boiling point impurities have been removed is stored in the column storage tank 23 provided at the bottom of the first distillation column 20. The tower storage tank 23 is heated by steam supplied from a steam header (not shown), and the tower storage tank 23 functions as a reboiler. The waste liquid L3 stored in the column storage tank 23 is pumped by the pump 23a and supplied to the lower end portion of the second distillation column 30 through the pipe 23b.

The waste liquid L3 is supplied to the lower end of the second distillation column 30 to remove the high boiling point impurities in the waste liquid L3.

That is, the 2nd distillation column 30 is a packed distillation column, and the packing material 30a is filled in the upper end side. When the waste liquid L3 is supplied to the lower end of the second distillation column 30, the recovery liquid L4 from which the high boiling point impurities are removed can be obtained from the top of the top of the second distillation column 30. From the bottom of the second distillation column 30, a waste liquid L5 containing a lot of high boiling point impurities, heavy metals and the like can be obtained.

The recovery liquid L4 from which the high boiling point impurities and the heavy metals are removed is discharged from the steam outlet 32 formed at the top of the column of the second distillation column 30. The recovery liquid L4 discharged from the steam outlet 32 is liquefied by the second condenser 34 and the second vent condenser 35, and then stored in the reflux tank 36. A part of the recovery liquid L4 stored in the reflux tank 36 is returned to the second distillation column 30 through the pipe 38 and the first recovery liquid 39a and the first liquid are passed through the pipes 37a and 37b. 2 is stored in the recovery liquid tank 39b. The reflux ratio at this time is appropriately determined while monitoring the solvent concentration of the recovery liquid L4 obtained from the top of the column and the like.

The waste liquid L5 containing a lot of high boiling point impurities and heavy metals is stored in the column storage tank 33 provided at the bottom of the second distillation column 30. The tower storage tank 33 is heated by steam supplied from a steam head not shown, and the tower storage tank 33 functions as a reboiler. A part of the waste liquid L5 stored in the tower storage tank 33 is pumped by the pump 33a and conveyed to the resin component removal apparatus 10 via the piping 33b. In addition, this waste liquid L5 is transferred to the resin component storage tank 4 as needed.

As described above, after the resin component (resist resin) is removed by the resin component removal apparatus 10, the waste liquid L discharged from the resist stripping step is subjected to low boiling point impurities (water) by the first distillation column 20. The high boiling point impurities are removed by the second distillation column 30. As a result, a high concentration of solvent can be recovered from the waste liquid L. As an example of the solvent which can be collect | recovered, solvents, such as the peeling liquid which mixed MEA and DMSO, the peeling liquid which mixed MEA and BDG, or the thinner which mixed PGMEA and PGME.

The solvent (recovery liquid L6) recovered from the waste liquid L is stored in the first recovery liquid tank 39a and the second recovery liquid tank 39b. One or both of the 1st collection liquid tank 39a and the 2nd collection liquid tank 39b can be used by operation of the valves 39c and 39d. For example, when the liquid level of the first recovery liquid tank 39a reaches a predetermined upper limit, changing the flow path so as to store the recovery liquid L6 in the second recovery liquid tank 39b by operating the valves 39c and 39d. It is possible.

The recovery liquid L6 stored in the first recovery liquid tank 39a and the second recovery liquid tank 39b is supplied to the filter 41 through the pipes 40a and 40b. Inside the filter 41, a filter medium to which fluorine resin processing has been applied is incorporated, and contaminants or the like mixed in the recovery liquid L6 are removed by the filter medium. A part of the recovered liquid L6 that has passed through the filter 41 is sampled by the concentration detecting means 42a to detect (measure) the concentration of the solvent and the impurity, and reuse it as a solvent in the resist stripping step. do.

As the concentration detecting means 42a, any means can be used as long as the concentration of the solvent or the impurities in the recovery liquid L6 can be detected. For example, an absorbance photometer or the like for measuring the absorbance of the recovery liquid L6 can be used as the concentration detecting means 42a. It is preferable that the density | concentration detection means 42a is a sensor which can measure the density | concentration of the solvent and impurity in recovery liquid L6 in real time. The concentration of the solvent finally recovered by this concentration detecting means 42a can be confirmed.

At the rear end of the second distillation column 30 (solvent component purification means 50), a solvent concentration detection means 42b for detecting the solvent concentration in the recovery liquid L4 is provided. After the recovery liquid L4 discharged from the steam outlet 32 of the second distillation column 30 is liquefied by the second condenser 34 and the second vent condenser 35 and stored in the reflux tank 36, a part thereof Is sampled by the solvent concentration detecting means 42b, and the concentration of the solvent is detected (measured). Based on the detection value by this solvent concentration detection means 42b, the replenishment amount of the solvent component (industrial grade solvent) by the solvent component replenishment means 60 is adjusted, and the solvent concentration at the rear end of the second distillation column 30 is adjusted. The control is performed to maintain the predetermined concentration range.

As the solvent concentration detecting means 42b, any means can be used as long as the concentration of the solvent in the recovery liquid L6 is detected. For example, an absorbance photometer or the like for measuring the absorbance of the recovery liquid L6 can be used as the solvent concentration detecting means 42b. It is preferable that the solvent concentration detection means 42b is a sensor capable of measuring the concentration of the solvent in the recovery liquid L6 in real time.

As described above, the solvent concentration detecting means 42b is preferably provided at the rear end side of the second distillation column 30, but may be provided at the front end of the second distillation column 30. It may be provided at both the front end and the rear end of the second distillation column (30). In addition, the solvent concentration detecting means 42b may be provided between the first distillation column 20 and the second distillation column 30. It may also be installed at the front end of the first distillation column 20.

In addition, when there are a plurality of components of the solvent, the concentration of each component is detected by the solvent concentration detecting means 42b, and the replenishment amount of each component is adjusted so that the concentration of each component is maintained within a predetermined range. It may be.

As shown in FIG. 2, the first vent capacitor 25, the second vent capacitor 35, the low boiling point impurity storage tank 29, the first recovery liquid tank 39a, and the second recovery liquid tank 39b are respectively. It is connected to the vacuum pump 43 via the piping 43a, 43b. Thereby, the inside of the 1st distillation column 20 and the 2nd distillation column 30 can be maintained at a pressure lower than atmospheric pressure, and distillation operation at lower temperature is attained. By distillation at a lower temperature, corrosion of the inner wall surface of the distillation column can be prevented, and thus the service life of the distillation column can be extended.

In addition, as shown in FIG. 2, piping 44a, 44b, 44c which can introduce nitrogen gas into the low boiling point impurity storage tank 29, the 1st collection liquid tank 39a, and the 2nd collection liquid tank 39b is provided. Each is connected. By sending nitrogen gas into the low boiling point impurity storage tank 29, the first recovery liquid tank 39a, and the second recovery liquid tank 39b, the liquid stored in each tank can be sent to the next process. In this case, it is not necessary to use a mechanical liquid feeding means such as a pump, so that generation of a defect such as clogging or abrasion can be prevented.

As the solvent recovery apparatus 1 in this embodiment, an industrial grade solvent L7 is replenished in one or both of the first distillation column 20 and the second distillation column 30. Thereby, the solvent refine | purified in the predetermined concentration range can be collect | recovered.

In addition, in this invention, as an "industrial grade solvent", it is a solvent which contains more impurities, such as heavy metals, than an electronic grade solvent. This industrial grade solvent is a lower grade solvent than the electronic grade solvent. On the other hand, as an "electronic grade solvent", it is a solvent refine | purified with higher purity and higher concentration than an industrial grade solvent. This electronic grade solvent can be obtained as a commercial item.

The industrial grade solvent L7 is stored in the solvent storage tank 51. When the industrial grade solvent L7 contains a plurality of solvent components, a plurality of solvent storage tanks may be provided. The industrial grade solvent L7 stored in the solvent storage tank 51 is pumped by the pump 52 and supplemented to one or both of the first distillation column 20 and the second distillation column 30 through the pipe 53. do. The piping 53 branches to the 1st distillation tower 20 and the 2nd distillation tower 30, respectively, and the valves 54a and 55a are provided in the piping 54 and the piping 55 after branching, respectively. By operating these valves 54a and 55a, the replenishment amount of the industrial grade solvent L7 to the first distillation column 20 and the second distillation column 30 can be controlled, respectively.

The solvent storage tank 51 corresponds to the solvent component replenishment means 60 in the present invention. The solvent component replenishing means 60 replenishes the solvent component in the waste liquid supplied to one or both of the first distillation column 20 and the second distillation column 30.

When the industrial grade solvent L7 is replenished in the middle portion of the first distillation column 20, not only the solvent component contained in the waste liquid L1 but also the replenished industrial grade L7 is present in the first distillation column 20. Then it is purified. That is, since the industrial grade solvent L7 itself is purified in the first distillation column 20 even without replenishing the highly purified electronic grade solvent, a high concentration of solvent can be finally recovered. In this first distillation column 20, low boiling point impurities (mainly water) in the industrial grade solvent L7 are removed.

When the industrial grade solvent L7 is replenished in the middle portion of the second distillation column 30, not only the solvent component contained in the waste liquid L3 but also the replenished industrial grade L7 is purified in the second distillation column 30. do. That is, since the industrial grade solvent L7 itself is purified in the second distillation column 30 without replenishing the highly purified electronic grade solvent, it is possible to finally recover the high purity solvent at a predetermined concentration. In this second distillation column 30, high boiling point impurities, heavy metals, and the like in the industrial grade solvent L7 are removed.

When many low boiling-point impurities are contained in the industrial grade solvent L7, it is preferable to replenish the industrial grade solvent L7 to the 1st distillation column 20. As shown in FIG. Thereby, since the industrial grade solvent L7 is refine | purified by the 1st distillation column 20, the low boiling point impurity in the industrial grade solvent L7 can be removed.

When the low boiling point impurity is not contained much in the industrial grade solvent L7 and a lot of the high boiling point impurity is contained, it is preferable to replenish the second distillation column 30 with the industrial grade solvent L7. Thereby, since the industrial grade solvent L7 is refine | purified by the 2nd distillation column 30, the high boiling point impurity in the industrial grade solvent L7 can be removed.

When the low boiling point impurities and the high boiling point impurities are contained in the industrial grade solvent L7, it is preferable to replenish the industrial grade solvent L7 in the distillation column, that is, the first distillation column 20, arranged upstream. Thereby, since the industrial grade solvent L7 is refine | purified by both the 1st distillation column 20 and the 2nd distillation column 30, the low boiling point impurity and the high boiling point impurity in the industrial grade solvent L7 can be removed.

In addition, an impurity concentration detecting means 42c may be provided in the middle of the pipe 53, and the concentration of impurities contained in the industrial grade solvent L7 may be measured in real time. And based on the measured value by this impurity concentration detection means 42c, it is also possible to change the replenishment place of the industrial grade solvent L7 between the 1st distillation column 20 and the 2nd distillation column 30 as mentioned above. It is possible.

That is, when the concentration of the low boiling point impurity contained in the industrial grade solvent L7 exceeds a predetermined value, the valves 54a and 55a are controlled so that the industrial grade solvent L7 flows through the first distillation column 20. . When the concentration of the low boiling point impurity contained in the industrial grade solvent L7 is equal to or less than a predetermined value, the valves 54a and 55a are controlled so that the industrial grade solvent L7 flows through the second distillation column 30. Thereby, various impurities contained in the industrial grade solvent L7 can be removed efficiently with lower energy.

As the impurity concentration detecting means 42c for measuring the concentration of the impurity contained in the industrial grade solvent L7, for example, an absorbance photometer or the like can be used. The above-described control can be realized by connecting this absorption photometer online to a control system of the entire apparatus, for example, a distributed control system (DCS) or the like.

According to the solvent collection | recovery apparatus 1 of this embodiment, the high purity solvent can be collect | recovered from waste liquid L at a predetermined density | concentration with high recovery rate. The recovered solvent can be reused in the resist stripping step without replenishing the electronic grade solvent.

According to the solvent recovery apparatus 1 of this embodiment, since the industrial grade solvent L7 may be replenished, procurement of the electronic grade solvent is unnecessary, and the solvent can be reused at a lower cost than the conventional apparatus.

Moreover, according to the solvent collection | recovery apparatus 1 of a present Example, the density | concentration of the solvent of collection liquid L6 can be adjusted by adjusting the replenishment amount of industrial grade solvent L7. For example, when the concentration of the solvent component of the recovery liquid L6 is lower than the predetermined value, the replenishment amount of the industrial grade solvent L7 containing the insufficient solvent component can be increased by operating the valves 54a and 55a. On the contrary, when the concentration of the solvent component of the recovery liquid L6 is larger than the predetermined value, the valve 54a, 55a can be operated to reduce the replenishment amount of the industrial grade solvent L7 including the excess solvent component. Thereby, it becomes possible to maintain the concentration of the solvent of the recovery liquid L6 finally obtained within a predetermined range. In this case, since there is no need to provide a concentration adjustment tank for adjusting the concentration of the solvent separately, the cost for installing the solvent recovery device 1 is greatly reduced.

Since the electronic grade solvent is refined with high purity, special handling for maintaining the quality is necessary, such as preservation in a sealed state. Therefore, the storage and the transportation of the electronic grade solvent are generally expensive, but according to the solvent recovery apparatus 1 of the present embodiment, the electronic grade solvent does not need to be used, so these costs are not at all. .

In addition, although the solvent component of the waste liquid L showed the example which mixed the monoethanolamine (MEA) and dimethyl sulfoxide (DMSO) in the Example mentioned above, this invention is not limited to this form. . For example, the solvent component of the waste liquid (L) is a stripping solution obtained by mixing monoethanolamine (MEA) and diethylene glycol monobutyl ether (BDG), monoethanolamine (MEA), dimethyl sulfoxide (DMSO), and N-methyl-. The present invention can also be applied to a thinner in which 2-pyrrolidone (NMP) is mixed, or thinner in which propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are mixed. In addition, as long as it is a solvent used at the resist peeling process, this invention can be applied also to the waste liquid containing another 1 type or multiple types of solvent.

According to the present invention, it is possible to provide a solvent recovery apparatus and a solvent recovery method capable of recovering a high concentration of solvent from waste liquid discharged from a resist stripping step. Moreover, the solvent collection | recovery apparatus and the solvent collection method which do not need to replenish the electronic grade solvent refine | purified with high purity can be provided.

Claims (20)

An apparatus for recovering a solvent from waste liquid discharged from a resist stripping process: Resin component removing means for removing the resin component contained in the waste liquid; Solvent component purifying means for purifying the solvent component contained in the waste liquid; And And a solvent component replenishing means for replenishing the solvent component in the waste liquid supplied to the solvent component refining means. The method of claim 1, The solvent component purifying means is constituted by a first distillation column for removing low-boiling impurities having a lower boiling point than the solvent component in the waste liquid, and a second distillation column for removing high-boiling impurities having a higher boiling point than the solvent component in the waste liquid. , And said solvent component replenishing means replenishes a solvent component in at least one of said first distillation column and said second distillation column. The method of claim 2, And said solvent component replenishing means replenishes an industrial grade solvent in at least one of said first distillation column and said second distillation column. The method of claim 3, wherein Impurity concentration detection means for detecting the concentration of impurities contained in the industrial grade solvent, And the solvent component replenishing means changes the replenishment of the industrial grade solvent between the first distillation column and the second distillation column on the basis of the detection value by the impurity concentration detecting means. The method according to any one of claims 1 to 4, A solvent concentration detecting means is provided at the rear end of the solvent component purifying means, and the solvent concentration detecting means detects the solvent concentration at the rear end of the solvent component purifying means, and the replenishment amount of the solvent component by the solvent component replenishing means. And adjusting the solvent concentration at the rear end of the solvent component purifying means within a predetermined concentration range. The method according to any one of claims 1 to 4, The solvent recovery apparatus of the said waste liquid is a peeling liquid of a resist. The method according to any one of claims 1 to 4, A solvent recovery device, characterized in that the solvent component in the waste liquid is thinner. The method according to any one of claims 1 to 4, The resin component removal means is a resin component removal device comprising an airtight cylindrical body having an inner circumferential surface as a heatable evaporation surface, and a rotating body disposed in the cylindrical body and radially having a brush on its outer circumferential surface. Recovery device. As a method of recovering the solvent from the waste liquid discharged from the resist stripping process: A resin component removing step of removing the resin component contained in the waste liquid; A solvent component purification step of purifying the solvent component contained in the waste liquid; And And a solvent component replenishing step of replenishing the solvent component in the waste liquid supplied to the solvent component refining process. The method of claim 9, The solvent component purification step includes a step of removing by a first distillation column that removes a low boiling point impurity having a lower boiling point than the solvent component in the waste liquid, and a agent for removing a high boiling point impurity having a higher boiling point than the solvent component in the waste liquid. 2 has a step of removing by distillation column, In the solvent component refilling step, a solvent component is replenished in at least one of the distillation column of the first distillation column and the second distillation column. The method of claim 10, In the solvent component replenishing step, a solvent recovery method comprising replenishing an industrial grade solvent to at least one of the first and second distillation columns. The method according to any one of claims 9 to 11, A solvent concentration detecting means is provided at the rear end of the solvent component purifying means, the solvent concentration detecting means detects the solvent concentration at the rear end of the solvent component purifying means, and based on the detected solvent concentration, A solvent recovery method comprising adjusting a replenishment amount of a solvent component and maintaining a solvent concentration at a rear end of the solvent component purifying means within a predetermined concentration range. The method according to any one of claims 9 to 11, The solvent recovery method of the said waste liquid is a peeling liquid of a resist. The method according to any one of claims 9 to 11, A solvent recovery method, characterized in that the solvent component in the waste liquid is thinner. delete The method of claim 5, wherein The solvent recovery apparatus of the said waste liquid is a peeling liquid of a resist. The method of claim 5, wherein A solvent recovery device, characterized in that the solvent component in the waste liquid is thinner. The method of claim 5, wherein The resin component removal means is a resin component removal device comprising an airtight cylindrical body having an inner circumferential surface as a heatable evaporation surface, and a rotating body disposed in the cylindrical body and radially having a brush on its outer circumferential surface. Recovery device. The method of claim 12, The solvent recovery method of the said waste liquid is a peeling liquid of a resist. The method of claim 12, A solvent recovery method, characterized in that the solvent component in the waste liquid is thinner.

Images