JP2017069273A - Carbon dioxide concentration management method and carbonic acid concentration management apparatus in resist stripping solution - Google Patents

Abstract

In a resist stripping solution, it has been reported that when the carbonic acid concentration increases, the stripping force decreases. However, when a specific resist stripping solution is used for a molybdenum / copper film, the molybdenum film increases due to an increase in carbonic acid concentration. The problem of dissolving was found.
[Solution]
A resist film made of a novolak resin and naphthoquinonediazo formed on a molybdenum / copper film,
Secondary amines,
A polar solvent;
A step of stripping with a resist stripping solution containing water;
Measuring the carbonic acid concentration in the resist stripping solution with an NDIR apparatus;
A carbon dioxide concentration management method in a resist stripping solution comprising a step of replacing at least a part of the resist stripping solution when the carbonic acid concentration in the resist stripping solution reaches 5000 ppm or more.
[Selection] Figure 1

Description

  The present invention relates to a method and an apparatus for managing the concentration of carbonic acid in a resist stripping solution used in a photolithography process, and in particular, when stripping a resist film having a novolak resin provided on a copper film with an alkaline solution. The present invention relates to a management method and a management apparatus for carbonic acid concentration in a stripping solution.

  The photolithography process is used for manufacturing an integrated circuit, and is currently used for forming a thin film transistor circuit of a display device such as a flat panel. In the etching, a resist film is formed into a shape of a pattern desired to be left or removed from the target thin film, the target thin film is processed by wet etching or dry etching, and the unnecessary resist film is then removed. In particular, there are currently many opportunities to process conductive lines by wet etching.

  Conventionally, conductive lines have been formed of aluminum. This is because the resist was able to be peeled off without affecting other films because of its high conductivity and relatively high resistance to alkaline solutions.

  However, when a large number of transistors are formed over a wide area, such as a flat panel, a material having higher conductivity than aluminum is required. Copper is inexpensive and has higher conductivity than aluminum, and is a suitable material for use in flat panels. However, since copper easily dissolves not only in an acidic solution but also in an alkaline solution, there is a problem that the copper film disappears in the resist stripping step.

  Further, in order to further strengthen the adhesive force to the base, a multilayer structure conductive line is used in which a molybdenum film is first formed on the base as a lower layer, and a copper film is formed on the molybdenum film as an upper layer. In the case of forming a conductive line having such a multilayer structure, a stripping solution that takes into consideration not only copper but also damage to molybdenum is required.

  In response to this problem, Patent Document 1 shows a technique that reduces the damage to the copper film and enables the resist removal of the copper film by adding an additive to the resist stripping solution. Thereafter, in Patent Document 2, an alkaline stripping solution using an amine was proposed.

  Furthermore, a resist stripping solution having a secondary amine, two types of polar solvents and water has been proposed (Patent Document 3). This resist stripping solution can strip the resist on the copper film without damaging the so-called positive resist containing the novolak resin formed on the copper film. In particular, it is effective for forming a conductive line having a multilayer structure in which molybdenum is used as a lower layer and a copper film is formed thereon.

  On the other hand, in Patent Document 4, there is a report that the stripping force decreases as the carbonic acid concentration in the resist stripping solution increases with respect to the lifetime of the resist stripping solution. In patent document 4, when the carbonic acid density | concentration in a resist stripping solution exceeds 3 weight%, it is supposed that peeling force will fall.

JP 2001-188363 A JP2012-113101A Japanese Patent Application No. 2014-231933 JP 2003-122029 A

  A resist stripping solution containing a secondary amine, two kinds of solvents and water can be suitably used for etching a molybdenum / copper film as described above. However, it was confirmed that the lower molybdenum film was dissolved before the resist peeling force decreased during use.

  In the case of a conductive line having a multilayer structure of a copper film and a molybdenum film, when the lower molybdenum film is dissolved, the copper film is peeled off from the base even if the copper film is not damaged, and the product becomes a defective product.

  The present invention has been conceived in view of the above problems, and has been found to be related to the dissolution of the molybdenum film and the increase of the carbonic acid component in the resist stripping solution in which a secondary amine having a five-membered ring structure is present. The present invention has been completed. This is because when the carbonic acid concentration in the resist stripping solution increases, a battery action occurs between the molybdenum film and the copper film in a solution containing a secondary amine having a five-membered ring structure, and a galvanic current flows. Was thought to dissolve.

  Accordingly, the present invention provides a method for managing the concentration of carbonic acid in a resist stripping solution for stably stripping a resist film containing a novolac resin on a molybdenum / copper film without dissolving the molybdenum film with the resist stripping solution described above. A management device is provided.

More specifically, the carbon dioxide concentration management method in the resist stripping solution according to the present invention is as follows:
A resist film made of a novolak resin and naphthoquinonediazo formed on a molybdenum / copper film,
Secondary amines,
A polar solvent;
A step of stripping with a resist stripping solution containing water;
Measuring the carbonic acid concentration in the resist stripping solution with an NDIR apparatus;
When the carbonic acid concentration in the resist stripping solution reaches 5000 ppm or more, the method includes a step of replacing at least a part of the resist stripping solution.

Moreover, the carbonic acid concentration management device in the resist stripper according to the present invention is:
A resist film made of a novolak resin and naphthoquinonediazo formed on a molybdenum / copper film,
Secondary amines,
A polar solvent;
A carbonic acid concentration management device in a resist stripping solution for use in a resist stripping device that is stripped while being circulated from a reservoir that stores a resist stripping solution containing water
A pipe for sample acquisition for taking out the resist stripping solution in the reservoir;
An NDIR device connected to the sample acquisition pipe;
It has a controller which transmits a signal for exchanging a part of the resist stripping solution when the carbonic acid concentration in the resist stripping solution measured by the NDIR apparatus reaches 5000 ppm or more.

  In the method for managing the carbonic acid concentration in the resist stripping solution according to the present invention, when the carbonic acid component concentration in the resist stripping solution reaches 5000 ppm or more, at least a part of the resist stripping solution is replaced. Maintained. Therefore, even if the resist film having a novolac resin formed on the molybdenum / copper film is peeled, the problem that the molybdenum film is dissolved and the copper film is peeled off from the base can be suppressed.

  Further, the carbonic acid component in the resist stripping solution is measured using a non-dispersive infrared absorber. Therefore, the sensitivity is very high, and even if the resist component dissolved in the resist stripping solution increases, the measurement can be continued with the same accuracy.

It is a figure which shows the structure of a resist stripping apparatus and the carbonic acid concentration management apparatus in the resist stripping solution which concerns on this invention. It is a figure which shows the structure of an NDIR apparatus. It is a graph which compares the measurement precision of NDIR and electrical conductivity. It is a SEM photograph which shows the mode of a molybdenum / copper film at the time of peeling a resist film with the resist stripping liquid from which carbonic acid concentration differs.

  Hereinafter, a carbon dioxide concentration management method and management apparatus in a resist stripping solution according to the present invention will be described with reference to the drawings. The following description shows one embodiment of the present invention, and modifications and implementations can be made without departing from the spirit of the present invention.

  FIG. 1 shows a configuration of a carbon dioxide concentration management device in a resist stripping solution according to the present invention. The carbonic acid concentration management device 1 in the resist stripping solution may be a part of the resist stripping device 50. The resist stripping device 50 includes a conveyor 54 that conveys the workpiece 62, a resist stripping solution storage section 52 provided below the conveyor 54, and a shower pipe 56 disposed from the storage section 52 to above the conveyor 54. A shower 58 for spraying a resist stripping solution on the object 62 to be processed and a pump 60 provided in the middle of the shower pipe 56 are included.

  Then, the carbonic acid concentration management device 1 in the resist stripping solution includes a sample acquisition pipe 12 that delivers the stripping solution from the reservoir 52, an NDIR device 10 connected to the pipe, and a control device connected to the NDIR device 10. 14 Further, the display device 16 may be connected to the control device 14.

  The sample acquisition pipe 12 is for acquiring a part of the resist stripping solution from the shower pipe 56 or the reservoir 52 of the resist stripping apparatus 50. Therefore, one end of the sample acquisition pipe 12 may be connected to at least one of the storage section 52 and the shower pipe 56. In addition, even if it is the sample of resist stripping liquid acquired from any place, it may be said that the resist stripping liquid in the storage part 52 was acquired. This is because the resist stripper circulates in the resist stripper 50.

  The other end of the sample acquisition pipe 12 is connected to an NDIR (Non Dispersive InfraRed) device (non-dispersive infrared absorption device) 10. As is well known, the NDIR apparatus 10 is an apparatus that measures the amount of absorption without splitting light. FIG. 2 shows a simple principle. The sampled resist stripping solution is put into the gas generation cell 20. An inorganic strong acid solution is injected into the gas generation cell 20 in advance.

  In the gas generation cell 20, bubbling is performed with an inert gas or the like in a state where the resist stripping solution and the inorganic strong acid solution are mixed. The carbonic acid component in the resist stripping solution becomes carbon dioxide gas by the inorganic strong acid solution in the gas generating cell 20, vaporizes, and is stored in the head space 20 h of the gas generating cell 20. It is introduced into the absorption chamber 24 together with the carrier gas.

  The absorption chamber 24 is formed of a transparent member at one end and the other end, and enters light from the light source 28 that has passed through the slit 26 from one end. Here, the light from the light source 28 is introduced into the absorption chamber 24 without being dispersed. Light that has passed through the other end of the absorption chamber 24 is introduced into the measurement chamber 30. The measurement chamber 30 is divided into at least two chambers by a thin film 32.

  The chamber closer to the absorption chamber 24 is a carbon dioxide chamber 34 filled with carbon dioxide, and the other chamber is a capacity chamber 36 for detecting volume such as capacitance. The capacity chamber 36 is provided with a terminal 38 t of a measuring device 38 that detects a volume change of the capacity chamber 36.

  The light emitted from the light source 28 passes through the absorption chamber 24. At this time, if the absorption chamber 24 contains carbon dioxide, only the wavelength component that responds to carbon dioxide is absorbed according to the amount of carbon dioxide. The light that has passed through the absorption chamber 24 enters the carbon dioxide chamber 34 and heats and expands the carbon dioxide by the amount of light remaining in the wavelength component that carbon dioxide can absorb. That is, the NDIR apparatus 10 measures the amount of carbon dioxide gas by replacing the absorption of light with a change in volume. The measured amount of carbon dioxide is transmitted to the control device 14 by the signal Sc.

  Note that the NDIR apparatus 10 can remove moisture in the vicinity of carbon dioxide and the absorption band from the sample gas sent to the absorption chamber 24, and drive out the carbonic acid component in the resist solution. Selection of a carrier gas with a different absorption band is a point for accurate measurement. In FIG. 2, the example which provided the cooler 22 in the middle of the carbon dioxide transfer piping 40 from the gas generation cell 20 to the absorption chamber 24 was shown.

  The operation of the carbon dioxide concentration management device 1 in the resist stripping solution having the above-described configuration will be described. Referring again to FIG. 1, the workpiece 62 is placed on the conveyor 54 and transferred into the resist stripping apparatus 50. The workpiece 62 is a substrate that has been subjected to processes such as exposure and rinsing. Therefore, at least a molybdenum / copper film and a resist film formed on the molybdenum / copper film exist on the substrate. The resist film is composed of a mixture of novolak resin and naphthoquinonediazo (NQD).

  When the resist film is exposed to light, naphthoquinonediazo changes to indenecarboxylic acid and dissolves in the alkaline solution. Therefore, the resist film remaining on the copper film in the resist stripping process is a resist film that has undergone a heating process (baking process) to mix the novolac resin and naphthoquinone diazo and strengthen the resist film.

  In the resist stripping device 50, the resist stripping solution collected in the storage unit 52 is transferred by the pump 60 through the shower pipe 56 to the shower 58. Then, a resist stripping solution is discharged from the shower 58 onto the workpiece 62. The discharged resist stripping solution strips the resist film on the workpiece 62 and returns to the storage unit 52. As described above, the resist stripping solution is sent out from the storage unit 52, peels off the resist film, and then returns to the storage unit 52 again. That is, it can be said that the resist stripping solution is circulated from the storage unit 52.

  The resist stripping solution is a mixture of a secondary amine, two types of polar solvents, and water. In particular, secondary amines having a five-membered ring structure are preferably used. Here, diethylene glycol monobutyl ether (BDG) and propylene glycol (PG) can be suitably used as the two types of polar solvents.

  Since the resist stripping solution is circulated, the concentration of the carbonic acid component gradually increases. Then, the molybdenum film under the object 62 is dissolved. Therefore, the concentration of the carbonic acid component is measured with the NDIR apparatus 10.

  More specifically, the NDIR device 10 acquires the resist stripping solution from the storage unit 52 in accordance with an instruction from the control device 14. The resist stripping solution is obtained by transferring the resist stripping solution into the NDIR device 10 through the sample obtaining pipe 12. The sample acquisition pipe 12 may be provided with a sample acquisition pump 13 in the middle.

  The NDIR apparatus 10 bubbles the sampled resist stripping solution with argon gas, and introduces the generated gas into the absorption chamber 24. Then, light is irradiated into the carbon dioxide chamber 34 through the absorption chamber 24 for a predetermined time. The volume expansion of carbon dioxide in the carbon dioxide chamber 34 is measured by the change in the capacity chamber 36. The NDIR device 10 notifies the control device 14 of this volume expansion as a signal Sc.

  The control device 14 that has received the signal Sc determines whether or not the volume expansion of carbon dioxide (proportional to the carbonic acid component in the resist stripping solution) exceeds a predetermined threshold value. If the threshold value is exceeded, a caution signal Sw is transmitted to the effect that the underlying molybdenum film may be dissolved. For example, the display 16 may be the destination of the transmission.

  The control unit (not shown) of the resist stripping apparatus 50 can perform a process of receiving this signal and replacing a part of the resist stripping solution.

  The carbonic acid concentration management device 1 in the resist stripping solution periodically detects the concentration of the carbonic acid component in the resist stripping solution in the reservoir 52. Therefore, the previous attention signal Sw is canceled when the concentration of the carbonic acid component in the resist stripping solution falls below the threshold value. Alternatively, a signal Sr that informs that the resist stripper can be used safely may be transmitted.

  As described above, according to the method and apparatus for managing the carbonic acid concentration in the resist stripping solution according to the present invention, the carbonic acid component in the resist stripping solution can be maintained at less than 5000 ppm. It can be suppressed and it can be said that it is substantially avoided.

  Examples of the method and apparatus for managing the carbonic acid concentration in the resist stripper according to the present invention will be described below.

<Reason for using the NDIR device 10>
In the present invention, it is necessary to detect a trace amount of the carbonic acid component in the resist stripping solution. In such a case, there is also a method for measuring the electrical conductivity of the resist stripping solution. However, since the resist stripping solution is an alkaline solution, there are various ionic components therein, and it is not suitable for a very small amount of measurement. It confirmed in the Example below.

The resist stripping solution used has the following composition.
Secondary amine (pyrrolidine) 1.5% by mass
Polar solvent (BDG (diethylene glycol monobutyl ether)) 40% by mass
Polar solvent (PG (propylene glycol)) 25.9% by mass
30% by weight of water
Additives Sorbitol 1.5% by mass
Additives Hydrazine monohydrate 0.1% by mass

Carbon dioxide gas was bubbled into the resist stripping solution. The amount of carbon dioxide prepared in the resist stripper from the weight of the resist stripper before and after bubbling was defined as the CO ₂ blending value (ppm). Next, FIG. 3 shows the results when the amount of CO ₂ in the resist stripping solution is measured by the NDIR apparatus 10 (the carrier gas is Ar gas) and when the electrical conductivity is measured.

FIG. 3A shows the case where the NDIR apparatus 10 is used, and FIG. 3B shows the case where the electrical conductivity is measured. In both graphs, the horizontal axis represents the CO ₂ preparation value (ppm). The vertical axis in FIG. 3A is the measured CO ₂ value (ppm), and the vertical axis in FIG. 3B is the electrical conductivity EC (mS / m).

In the case of the NDIR apparatus 10, even if the CO ₂ preparation amount is less than 5000 ppm, good linearity is shown. On the other hand, in the case of electrical conductivity, the linearity deteriorates when the blending ratio is less than 4000 ppm. In addition, the change in electrical conductivity is small with respect to the CO ₂ preparation value, and the sensitivity is poor.

  In particular, in Examples described later, it was confirmed that the molybdenum film was dissolved when the carbonic acid component in the resist stripping solution was 5000 ppm. Therefore, in the carbon dioxide concentration management method (or management device) in the resist stripping solution according to the present invention, it is desirable to measure the carbonic acid concentration using the NDIR device 10.

<Dissolution of molybdenum film (corrosion evaluation)>
For some resist stripping solutions, the state of dissolution of the molybdenum film (hereinafter also referred to as “corrosive”) due to changes in the carbonic acid concentration was confirmed by experiments.

  In each case, the resist used was 50% by mass of novolak resin and 50% by mass of naphthoquinone diazo.

  As a substrate for corrosive evaluation, a silicon thermal oxide film is formed to a thickness of 100 nm on a silicon substrate, a copper film is formed to a thickness of 300 nm on the silicon thermal oxide film by a sputtering method, and a Cu film sample is produced. did. This is called “Cu gate”. Similarly, a molybdenum film is formed to a thickness of 20 nm on a silicon thermal oxide film on a silicon substrate, and a copper film is subsequently formed to a thickness of 300 nm to form a Cu / Mo (molybdenum / copper film) film. A laminated film sample was prepared. This is called “Cu / Mo gate”. In addition, an aluminum film was formed to a thickness of 300 nm on the silicon thermal oxide film on the silicon substrate to produce an Al film sample. This is called “Al gate”.

  On these evaluation samples, a resist patterned into a wiring shape was formed with a thickness of about 1 μm, and used as a base material for corrosive evaluation. In other words, the corrosive evaluation substrate includes a Cu film, a Cu / Mo film, and an Al film formed on a silicon thermal oxide film on a silicon substrate, and a resist layer formed in a wiring shape thereon. Consists of. In addition, these board | substrates for corrosivity evaluation performed the heat processing (baking process) for 140 degreeC for 5 minutes.

  Etching was performed by immersing these corrosive evaluation substrates in an etchant for copper film or aluminum film for just etching time. Thereafter, the substrate for corrosivity evaluation after etching was immersed in a sample resist stripping solution maintained at 40 ° C. for 2 minutes to strip the resist film. After the corrosive evaluation substrate immersed in the sample resist stripping solution for 2 minutes was washed and dried, the surface of the copper film was observed by SEM (Scanning Electron Microscope). The SEM observation conditions were 30 kV and a magnification of 30,000.

  The evaluation method was a round mark when no corrosion was observed on the copper film, molybdenum film, or aluminum film by SEM observation, and a cross mark when clear corrosion or peeling of the film was observed. Moreover, although it cannot evaluate to a cross mark, the state considered that it would be desirable to replace the stripping solution was a triangle mark.

  The judgment of just etching was made when the silicon thermal oxide film was visually confirmed from the start of etching.

  Next, the composition of the sample resist stripping solution will be shown. In addition, although the carbonic acid concentration in the composition is mass% (indicated in ppm), since it is added later, the amount is based on 100 mass% of other components. That is, when the carbonic acid concentration is included, the following composition exceeds 100% by mass.

  Examples of changing the composition of the resist stripping solution are given below.

Example 1
Example 1 used the sample resist stripping solution with the following composition.
Secondary amine (pyrrolidine) 1.5% by mass
Polar solvent (BDG (diethylene glycol monobutyl ether)) 40.0% by mass
Polar solvent (PG (propylene glycol)) 25.9% by mass
31.0% by weight of water
The following are included as additives.
Sorbitol 1.5% by mass
Hydrazine monohydrate 0.1% by mass
Carbon dioxide concentration 20ppm

(Example 2)
In Example 2, a sample resist stripping solution having the following composition was used.
Secondary amine (pyrrolidine) 1.5% by mass
Polar solvent (BDG (diethylene glycol monobutyl ether)) 40.0% by mass
Polar solvent (PG (propylene glycol)) 25.9% by mass
31.0% by weight of water
The following are included as additives.
Sorbitol 1.5% by mass
Hydrazine monohydrate 0.1% by mass
Carbon dioxide concentration 2000ppm

(Comparative Example 1)
Comparative Example 1 was a sample resist stripping solution having the following composition.
Secondary amine (pyrrolidine) 1.5% by mass
Polar solvent (BDG (diethylene glycol monobutyl ether)) 40.0% by mass
Polar solvent (PG (propylene glycol)) 25.9% by mass
31.0% by weight of water
The following are included as additives.
Sorbitol 1.5% by mass
Hydrazine monohydrate 0.1% by mass
Carbonic acid concentration 5000ppm

  That is, Example 1, Example 2, and Comparative Example 1 have the same composition as the stripping solution, but differ only in the concentration of carbonic acid contained. Their compositions and results are shown in Table 1.

  Referring to Table 1, when the carbonic acid concentration was 20 ppm, there was no damage to the molybdenum / copper film exposed to the stripping solution. However, it was confirmed that when the carbonic acid concentration was 5000 ppm, the molybdenum film was dissolved and disappeared. On the other hand, when only the copper film or only the aluminum film was used, no damage was caused to the film.

  FIG. 4 shows an SEM photograph at this time. In FIG. 4, the white arrow represents a length of 1 μm. 4A shows the case where the carbonic acid concentration is 2000 ppm (Example 2), and FIG. 4B shows the case where the carbonic acid concentration is 5000 ppm (Comparative Example 1). Referring to FIG. 4A, the base, the molybdenum film, the inclined portion, and the copper film are shown from the left in the photograph. Here, the inclined portion is a portion where the cross section of the copper film is inclined. The presence of a molybdenum film (indicated as Mo) was slightly confirmed beside the inclined portion (cross section) of the copper film (indicated as Cu). The reason why the molybdenum film is only slightly visible in FIG. 4A is that the molybdenum film is thin and disposed in the lower layer.

  On the other hand, in FIG. 4B, the molybdenum film was dissolved and disappeared, and its presence could not be confirmed by SEM. In this example, the copper film is not in a state of peeling from the base. However, the disappearance due to the dissolution of the molybdenum film significantly reduces the adhesion between the base and the copper film, and causes a failure in energization, so it must be suppressed.

  This phenomenon is considered to be electrolytic corrosion due to galvanic current generated between copper, which is a noble metal, and molybdenum, which is a base metal. However, it should be noted here that the copper film does not dissolve in the resist stripping solution, which is an alkaline solution, but molybdenum dissolves. With respect to corrosion resistance, molybdenum is stronger than copper, and the copper film is first corroded in the resist stripping solution, which is an alkaline solution. However, when a secondary amine having a five-membered ring structure is included in the resist stripping solution, the corrosion rate of copper is reduced by so-called cathodic protection, and molybdenum is considered to be corroded first.

  From the above, it is understood that when a secondary amine is used as the stripping solution, it is preferable to replace the stripping solution when the content of carbonic acid is 5000 ppm or more.

  The resist stripping solution according to the present invention can be suitably used for a method of managing the carbonic acid concentration in a resist stripping solution based on the composition of a secondary amine, a polar solvent and water using a molybdenum / copper film.

DESCRIPTION OF SYMBOLS 1 Carbon dioxide concentration management apparatus in resist stripping solution 10 NDIR apparatus 12 Pipe for sample acquisition 13 Sample acquisition pump 14 Controller 16 Display device 20 Gas generation cell 20h Head space 22 Cooling machine 24 Absorption chamber 26 Slit 28 Light source 30 Measurement chamber 32 Thin film 34 Carbon dioxide chamber 36 Capacity chamber 38 Measuring instrument 38 t Terminal 40 Carbon dioxide transfer piping 50 Resist stripping device 52 Storage section 54 Conveyor 56 Shower pipe 58 Shower 60 Pump 62 Processed object Sc signal Sw signal Sr signal

Claims (9)

A resist film made of a novolak resin and naphthoquinonediazo formed on a molybdenum / copper film,
Secondary amines,
A polar solvent;
A step of stripping with a resist stripping solution containing water;
Measuring the carbonic acid concentration in the resist stripping solution with an NDIR apparatus;
A carbon dioxide concentration management method in a resist stripping solution comprising a step of replacing at least a part of the resist stripping solution when the carbonic acid concentration in the resist stripping solution reaches 5000 ppm or more.   The method for controlling the concentration of carbonic acid in a resist stripping solution according to claim 1, wherein the secondary amine has a five-membered ring structure.   The method for managing the concentration of carbonic acid in a resist stripping solution according to claim 1, wherein the secondary amine is pyrrolidine. The polar solvent is
BDG (diethylene glycol monobutyl ether),
4. The method for controlling the concentration of carbonic acid in a resist stripping solution according to claim 1, wherein the solvent is a mixed polar solvent with PG (propylene glycol).   Furthermore, sorbitol and hydrazine monohydrate are contained as an additive, The carbonic acid concentration management method in the resist stripping solution of any one of Claims 1 thru | or 4 characterized by the above-mentioned. A resist film made of a novolak resin and naphthoquinonediazo formed on a molybdenum / copper film,
Secondary amines,
A polar solvent;
A carbonic acid concentration management device in a resist stripping solution for use in a resist stripping device that is stripped while being circulated from a reservoir that stores a resist stripping solution containing water
A pipe for sample acquisition for taking out the resist stripping solution in the reservoir;
An NDIR device connected to the sample acquisition pipe;
In the resist stripping solution, comprising a controller for transmitting a signal for replacing a part of the resist stripping solution when the carbonic acid concentration in the resist stripping solution measured by the NDIR apparatus reaches 5000 ppm or more. Carbon dioxide concentration management device.   The carbonic acid concentration management device in a resist stripping solution according to claim 6, wherein the secondary amine is pyrrolidine. The polar solvent is BDG (diethylene glycol monobutyl ether);
8. The carbon dioxide concentration management device in a resist stripping solution according to claim 6, wherein the solvent is a mixed polar solvent with PG (propylene glycol). The resist stripping solution is
Furthermore, sorbitol and hydrazine monohydrate are included as an additive, The carbonic acid concentration management apparatus in the resist stripping solution described in any one of Claims 6 thru | or 8 characterized by the above-mentioned.