Patent ID: 12188901

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a management method, a measuring method, a measuring device, a crystal oscillator sensor, and a set of the present invention will be described in detail on the basis of preferred embodiments shown in the accompanying drawings.

In addition, the drawings described below are exemplary for explaining the present invention, and the present invention is not limited to the drawings shown below.

In addition, in the following, “to” indicating a numerical range includes numerical values described on both sides. For example, in a case where ε is a numerical value α to a numerical value β, the range of ε is a range including the numerical value α and the numerical value β and is α≤ε≤β in mathematical symbols.

[Measuring Device]

FIG.1is a schematic diagram showing an example of a measuring device according to an embodiment of the present invention, andFIG.2is a schematic cross-sectional view showing a first example of a crystal oscillator sensor according to the embodiment of the present invention.

A measuring device10shown inFIG.1is a device that senses impurities in a chemical liquid containing an organic solvent. The measuring device10can be used to manage the purity of a target chemical liquid.

The measuring device10includes a flow cell unit12, an oscillation unit14, a detection unit15, a calculation unit16, a memory18, a supply unit20, and a control unit22. The measuring device10further includes a display unit23, an output unit24, and an input unit25.

The control unit22controls the operations of the flow cell unit12, the oscillation unit14, the detection unit15, the calculation unit16, the memory18, and the supply unit20. Additionally, the control unit22controls respective components of the measuring device10on the basis of the operation control of the display unit23, the output unit24, and the input information from the input unit25.

The flow cell unit12has a crystal oscillator sensor26including an adsorption layer34(refer toFIG.2) that adsorbs the impurities and a crystal oscillator27(refer toFIG.2), and a temperature adjustment unit28for maintaining the temperature of the target chemical liquid supplied to the flow cell unit12. The flow cell unit12will be described in detail below.

The oscillation unit14is electrically connected to the crystal oscillator sensor26. The oscillation unit14oscillates the crystal oscillator27at a resonance frequency. The oscillation unit14applies a high-frequency signal of a sine wave to the crystal oscillator sensor26as a frequency signal, and has an oscillation circuit (not shown).

Additionally, the detection unit15is electrically connected to the oscillation unit14. The detection unit15measures the resonance frequency of the crystal oscillator27and detects the amount of change in the resonance frequency of the crystal oscillator resulting from contact with the target chemical liquid. In addition, the detection unit15may detect a difference in the amount of change in the plurality of resonance frequencies obtained by using the plurality of adsorption layers, which will be described below.

The detection unit15takes in the frequency signal of the oscillation unit14, samples the frequency signal, for example, every second, and stores the sampled frequency signal in a memory18as time-series data. In addition, the memory18stores measurement time and frequency tolerance. On the basis of the measurement time and the frequency tolerance, the detection unit15measures the resonance frequency of the crystal oscillator27and detects the amount of change in the resonance frequency of the crystal oscillator resulting from contact with the target chemical liquid.

The measurement time is the time required to obtain the amount of change in the resonance frequency resulting from the contact of the impurities with the adsorption layer34. The measurement time is not particularly limited and is appropriately determined depending on the supply flow rate of the target chemical liquid, or the like. For example, 10 minutes or more is preferable, and 30 minutes or more is preferable. An upper limit is not particularly limited, but from the viewpoint of productivity, 3 hours or less is preferable, and 2 hours or less is more preferable.

The frequency tolerance is a threshold value for determining whether or not a value that is an index of frequency stabilization has become a sufficiently small value equivalent to the stabilization in a case where whether or not the frequency is stable is determined. The frequency tolerance is appropriately set depending on, for example, set measurement sensitivity. For example, in a case where the resonance frequency is 30 MHz, an error range allowed in the measurement time in a case where the measurement sensitivity is 5 Hz is set to, for example, 0.5 Hz. This is equivalent to 0.0167 ppm. The tolerance corresponding to the error range is equal to or less than 1.67×10−8(0.0167 ppm).

The detection unit15detects the frequency by, for example, a frequency counter that is a known circuit. In addition to this, for example, as described in JP2006-258787A, a frequency signal may be analog-to-digital converted and processed by a carrier move to generate a rotation vector that rotates at the frequency of the frequency signal, and the frequency may be detected by using a method such as finding the velocity of the rotation vector. In the detection unit15, it is preferable to use such digital processing because the detection accuracy of the frequency is high.

The calculation unit16reads out the permissible range of the amount of change in the resonance frequency based on the preset purity of the target chemical liquid stored in the memory18, and compares the permissible range of the amount of change in the resonance frequency stored in the memory18with the amount of change in the resonance frequency obtained by the detection unit15to manage the purity of the chemical liquid. For example, in a case where the amount of change in the resonance frequency is within the permissible range through the above-described comparison, the display unit23displays that the purity of the chemical liquid is within a permissible range. On the other hand, in a case where the amount of change in the resonance frequency exceeds the permissible range, the display unit23displays that the purity of the chemical liquid exceeds the permissible range. In addition to this, in a case where the amount of change in the resonance frequency is within the permissible range, an event in which the purity of the chemical liquid is within the permissible range may be output to the output unit24. On the other hand, in a case where the amount of change in the resonance frequency exceeds the permissible range, an event in which the purity of the chemical liquid exceeds the permissible range may be output to the output unit24.

The memory18stores the above-described amount of change in the resonance frequency based on the preset purity of the target chemical liquid and the permissible range thereof. In addition to this, the memory18may store the resonance frequency of the crystal oscillator, or the like. As will be described below, in a configuration in which a plurality of electrodes are provided on the crystal oscillator, the difference between the resonance frequency of each electrode and the resonance frequency between the electrodes may be stored.

In addition, as for the amount of change in the resonance frequency stored in the memory18, for example, as shown inFIG.3, a calibration curve L showing the relationship between the amount of impurities in a specific target chemical liquid and the resonance frequency of the crystal oscillator27can be found, and on the basis of the calibration curve L, the relationship between the amount of impurities in the specific target chemical liquid and the amount of change in the resonance frequency can be obtained. Additionally, by setting the permissible range for the calibration curve L, the permissible range of the amount of change in the resonance frequency can be set. The amount of impurities on the calibration curve L shown inFIG.3is, for example, the amount of impurities measured using a surface inspection device. More specifically, after a predetermined amount of the target chemical liquid is applied to a predetermined substrate (for example, a silicon wafer), the number of defects on the substrate to which the target chemical liquid has been applied is measured using the surface inspection device, and the number of defects obtained can be used as the amount of impurities.

In addition, examples of the surface inspection device include a device that irradiates a substrate, to which the target chemical liquid has been applied, with a laser beam, detects the laser beam scattered due to defects present on the substrate, and detects impurities present on the substrate. By performing measurement while rotating the substrate during irradiation with the laser beam, the coordinate position of a defect can be derived from the rotation angle of the substrate and the radial position of the laser beam. Examples of such a device include “SP-5” made by KLA Tencor, but may include a surface inspection device (typically a succession machine of “SP-5”, or the like) having a resolution equal to or higher than that of “SP-5”, in addition to this.

The display unit23displays the amount of change in the resonance frequency obtained by the calculation unit16, and includes, for example, a display. The display is not particularly limited as long as the display can display texts and images, and a liquid crystal display device or the like is used. Additionally, the items displayed on the display unit23are not limited to the amount of change in the obtained resonance frequency but may be a resonance frequency. As will be described below, a difference in the amount of change in a plurality of resonance frequencies obtained by using a plurality of adsorption layers may be displayed, and various setting items, input information, and the like, which are set by the measuring device10, may be displayed.

The output unit24displays the obtained amount of change in the resonance frequency, the resonance frequency, or the like on a medium. More specifically, for example, at least one of texts, symbols, or barcodes is used for display. The output unit24includes a printer or the like. An information display unit on which resonance frequency information on the chemical liquid of a set described below is displayed can be obtained by the output unit24.

The input unit25is various input devices for inputting various information from a mouse, a keyboard, and the like according to an operator's instruction. For example, the setting of the measuring device10and the call of data from the memory18are performed via the input unit25.

In addition, the input unit25also includes an interface for inputting information to be stored in the memory18, and the information is stored in the memory18through an external storage medium or the like.

In addition, the measuring device10only needs to be able to obtain the obtained amount of change in the resonance frequency and does not necessarily require a configuration other than obtaining the amount of change in the resonance frequency. From this, for example, the calculation unit16is necessary in the management method but is not necessarily required in the measuring device10for obtaining the amount of change in the resonance frequency.

The flow cell unit12is a sensing unit that senses the impurities in the chemical liquid containing an organic solvent. The flow cell unit12is connected to the supply unit20by using a first tube29aand a second tube29b. The supply unit20allows the target chemical liquid to pass through the first tube29a, supplies the target chemical liquid to the crystal oscillator, and allows the target chemical liquid to pass through the second tube29bto recover the target chemical liquid. The supply unit20allows the target chemical liquid to pass through the first tube29aand the second tube29bwithout coming into contact with the target chemical liquid, and for example, a peristaltic pump is used. The supply unit20is not particularly limited as long as the supply unit can supply the liquid without coming into contact with the target chemical liquid, and for example, a syringe pump can be used.

The temperature adjustment unit28has, for example, a Peltier element. The temperature of the target chemical liquid is maintained by the Peltier element. Accordingly, the temperature of the target chemical liquid can be kept constant, and the viscosity of the target chemical liquid can be kept within a certain range. Fluctuations in measurement conditions of the purity can be reduced. In addition, the configuration of the temperature adjustment unit28is not particularly limited as long as the temperature of the target chemical liquid can be maintained.

[Crystal Oscillator Sensor]

As described above, the crystal oscillator sensor26has the crystal oscillator27. However, the crystal oscillator27has, for example, a disk shape, and an electrode30is provided on a front surface27aof the crystal oscillator27, and an electrode31is provided on a back surface27b.

The adsorption layer34for adsorbing the impurities is provided on a surface30aof the electrode30provided on the front surface27aof the crystal oscillator27. The target chemical liquid containing an organic solvent is brought into contact with the adsorption layer34.

As the crystal oscillator27, for example, an AT-cut type crystal oscillator is used. The AT-cut type crystal oscillator is an oscillator cut out at an angle of 35°15′ from a Z axis of artificial quartz. The crystal oscillator sensor26is not limited to the configuration shown inFIG.2.

The oscillation unit14is electrically connected to the electrode30and the electrode31. The oscillation unit14applies a high-frequency signal of a sine wave to the electrodes30and31as a frequency signal, and has, for example, an oscillation circuit. The crystal oscillator27vibrates at the resonance frequency by the oscillation unit14. The resonance frequency of the crystal oscillator27is, for example, 27 MHz or 30 MHz.

The adsorption layer34is made of at least one material of, for example, Si, Au, SiO2, SiOC, Cu, Co, W, Ti, TiN, Ta, TaN, or a photosensitive resin composition. The types of impurities that are easily adsorbed differ depending on materials that constitute the adsorption layer. Thus, for example, in a case where the amount of impurities in the target chemical liquid is found by the above-described surface inspection device and the number of defects is associated with the amount of change in the resonance frequency, it is preferable that the substrate to which the chemical liquid used to measure the number of defects with the surface inspection device is applied and the adsorption layer are made of the same material. That is, in a case where an Si layer is used as the adsorption layer, it is preferable to use an Si substrate (silicon wafer) as the substrate.

The adsorption layer34can be formed by a vapor phase method such as a sputtering method, a chemical vapor deposition (CVD) method, a coating method, or the like.

In addition, the type of the photosensitive resin composition is not particularly limited, and examples thereof include known photosensitive resin compositions. Examples of components contained in the photosensitive resin composition include a resin having the group that produces a polar group by the action of an acid, and a photoacid generator. The photosensitive resin composition may further contain a basic compound, a hydrophobic resin, or the like.

In the crystal oscillator sensor26, the resonance frequency of the crystal oscillator27changes depending on the amount of impurities adsorbed on the adsorption layer34. By measuring the resonance frequency before and after contact with the target chemical liquid, the amount of change in the resonance frequency can be obtained. In addition, the amount of change ΔF in the resonance frequency of the crystal oscillator27can be expressed by the following equation referred to as the Sauerbrey equation. In the following equation, F0is the resonance frequency, Δm is mass change amount, ρ is the density of the crystal, μ is the shear stress of the crystal, and A is the area of the electrodes. From the following equation, by increasing the resonance frequency F0of the crystal oscillator, the mass detection sensitivity can be increased, that is, the measurement accuracy of impurities can be enhanced.

Δ⁢F=-2⁢F02ρ⁢μ⁢Δ⁢mA[Equation⁢1]
[Flow Cell Unit]

FIG.4is a schematic diagram showing an example of the flow cell unit of the measuring device according to the embodiment of the present invention.

In the flow cell unit12, for example, the crystal oscillator sensor26is disposed on the temperature adjustment unit28via a seal portion43. The seal portion42is provided on the crystal oscillator sensor26along the periphery of the crystal oscillator27. A block40is disposed on the seal portion42. The block40is provided with a supply passage40afor supplying the target chemical liquid to the crystal oscillator sensor26. The supply passage40ais connected to the first tube29a. Additionally, the block40is provided with a discharge passage40bfor discharging the target chemical liquid from the crystal oscillator sensor26. The discharge passage40bis connected to the second tube29b. That is, the flow cell unit12further has the seal portion42disposed on the crystal oscillator sensor26, the supply passage40athat is disposed on the crystal oscillator sensor26via the seal portion42and supplies the target chemical liquid to the crystal oscillator sensor26, the block40provided with the discharge passage40bfor discharging the target chemical liquid from the crystal oscillator sensor26, and a liquid feeding unit including the first tube29aconnected to the supply passage40aand the second tube29bconnected to the discharge passage40b.

The target chemical liquid that has passed through the first tube29aand the supply passage40ais supplied to a region44formed by being surrounded by the crystal oscillator sensor26, the seal portion42, and the block40. That is, the seal portion42is disposed outside the region44. Accordingly, the target chemical liquid comes into contact with the adsorption layer34on the surface30aof the electrode30of the crystal oscillator27of the crystal oscillator sensor26. Additionally, the target chemical liquid passes through the discharge passage40band the second tube29band is discharged from the region44. The first tube29aand the discharge passage40b, and the second tube29band the discharge passage40bconstitute a circulation line.

The movement of the target chemical liquid between the first tube29aand the supply passage40aand the second tube29band the discharge passage40bis performed by the supply unit20(refer toFIG.1) as described above.

For example, the seal portion42and the seal portion43have the same size and include, for example, an O-ring. In addition, the target chemical liquid is not supplied to a region45formed by being surrounded by the crystal oscillator sensor26, the seal portion43, and the temperature adjustment unit28.

Additionally, in the flow cell unit12, by making at least a part of a liquid contact portion coming into contact with the target chemical liquid of a fluorine-based resin, elution to the target chemical liquid can be suppressed and a decrease in measurement accuracy of the purity can be suppressed, which is preferable.

In the measuring device10, a face, which is formed by being surrounded by the above-described crystal oscillator sensor26, the seal portion42, and the block40and constitutes the region44for holding the target chemical liquid on the crystal oscillator sensor26, corresponds to a part of the liquid contact portion that comes into contact with the target chemical liquid. In addition to the region44, in the supply unit where the target chemical liquid is brought into contact with the crystal oscillator sensor26, the portion of the liquid feeding unit that feeds the target chemical liquid to the crystal oscillator sensor is also the liquid contact portion. It is preferable that at least a part of the liquid contact portion is made of the fluorine-based resin. That is, it is preferable that at least a part of the liquid contact portion coming into contact with the target chemical liquid in the measuring device (the measuring device having the above-described crystal oscillator sensor) that senses the impurities in the chemical liquid containing an organic solvent is made of the fluorine-based resin. In addition, as the above liquid contact portion, a liquid contact portion other than the adsorption layer and the crystal oscillator is preferable. Examples of the liquid feeding unit include a supply line that feeds the liquid in one direction and a circulation line that circulates and supplies the target chemical liquid to the crystal oscillator sensor.

More specifically, inFIG.4, the liquid contact portion is a face40ccoming into contact with a region44of the block40of the flow cell unit12, a face42athat is a portion coming into contact with the region44of the seal portion42for holding the target chemical liquid disposed on the crystal oscillator sensor26in the region44, the supply passage40aof the block40, and the discharge passage40bof the block40. Additionally, it is preferable that the inside of the first tube29aand the inside of the second tube29bare also liquid contact portions coming into contact with the target chemical liquid, and the portions of the first tube29aand the second tube29bcoming into contact with the target chemical liquid are made of the fluorine-based resin.

Particularly, it is preferable that at least a part of the liquid contact portion coming into contact with the target chemical liquid of the seal portion42, the liquid contact portion coming into contact with the target chemical liquid of the block40, and the liquid contact portion coming into contact with the target chemical liquid of the liquid feeding unit are made of the fluorine-based resin.

The fluorine-based resin may be any resin containing a fluorine atom.

The fluorine-based resin is not particularly limited as long as the fluorine-based resin is a resin (polymer) containing a fluorine atom, and a known fluorine-based resin can be used. Examples of the fluorine-based resin include polytetrafluoroethylene (PTFE, Tensile strength: to 35 MPa, Shore D Hardness: 50 to 55), perfluoroalkoxyalkane, polychlorotrifluoroethylene, polyvinylidene fluoride, an ethylene tetrafluoroethylene copolymer, an ethylene chlorotrifluoroethylene copolymer, a perfluoroethylene propene copolymer, a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer, and a cyclized polymer of perfluoro (butenyl vinyl ether) (Cytop (registered trademark)).

Particularly, in a case where the liquid contact portion (the portion coming into contact with the target chemical liquid) of the block40of the flow cell unit12coming into contact with the target chemical liquid is made of a fluorine-based resin, it is preferable that the tensile strength of the above fluorine-based resin is 20 to 60 MPa. Additionally, the Shore D hardness of the fluorine-based resin is preferably 60 to 80.

It is preferable that examples of the fluorine-based resin constituting the liquid contact portion coming into contact with the target chemical liquid of the block40include the perfluoroalkoxyalkane (PFA, Tensile strength: 25 to 35 MPa, Shore D hardness: 62 to 66), the ethylene tetrafluoroethylene copolymer (ETFE, Tensile strength: 38 to 42 MPa, Shore D hardness: 67 to 78), the perfluoroethylene propene copolymer (FEP, tensile strength: 20 to 30 MPa, Shore D hardness: 60 to 65), the polychlorotrifluoroethylene (PCTFE, Tensile strength: 31 to 41 MPa, Shore D hardness: 75 to 80), or the polyvinylidene fluoride (PVDF, Tensile strength: 30 to 60 MPa, Shore D hardness: 64 to 79).

In addition, the method of measuring the tensile strength is performed according to JIS K 7161.

The method of measuring the Shore D hardness is performed according to JIS K 7215.

Additionally, it is preferable that the fluorine-based resin constituting the liquid contact portion (a portion coming into contact with the target chemical liquid) coming into contact with the target chemical liquid in the liquid feeding unit that feeds the target chemical liquid to the region44has a repeating unit (hereinafter, also simply referred to as “specific repeating unit”) including a fluorine atom, a carbon atom, and an atom other than the fluorine atom and the carbon atom. Examples of the above other atoms include a hydrogen atom and a chlorine atom. That is, it is preferable that the specific repeating unit includes the fluorine atom, the carbon atom, at least one other atom selected from the group consisting of the hydrogen atom and the chlorine atom.

As the fluorine-based resin constituting the portion of the above liquid feeding unit coming into contact with the target chemical liquid, a ternary copolymer (THV soft fluororesin) of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride, the polyvinylidene fluoride, and the ethylene tetrafluoroethylene copolymer, or the polychlorotrifluoroethylene is preferable.

The method of measuring the tensile strength and the Shore D hardness is as described above.

The portion (the face42athat is a portion coming into contact with the region44), coming into contact with the target chemical liquid, of the seal portion42that holds the target chemical liquid disposed on the crystal oscillator sensor26in the region44is preferably made of the fluorine-based resin.

The tensile strength of the fluorine-based resin constituting the portion of the above seal portion42coming into contact with the target chemical liquid is preferably 20 to 40 MPa. Additionally, the Shore D hardness of the fluorine-based resin constituting the portion of the seal portion42coming into contact with the target chemical liquid is preferably 56 to 70. Additionally, the bending modulus of the fluorine-based resin constituting the portion of the above seal portion42coming into contact with the target chemical liquid is preferably 0.5 to 3 GPa.

In a case where the fluorine-based resin constituting the portion of the above seal portion42coming into contact with the target chemical liquid satisfies the above tensile strength, Shore D hardness, and bending modulus, the oscillation of the crystal oscillator sensor26is not hindered and more stable measurement can be carried out.

The method of measuring the tensile strength and the Shore D hardness is as described above.

The method of measuring the bending modulus is performed according to HS K7171.

As the fluorine-based resin constituting the portion of the above seal portion42coming into contact with the target chemical liquid, include the perfluoroalkoxyalkane, the perfluoroethylene propene copolymer, the ethylene chlorotrifluoroethylene copolymer, the ethylene tetrafluoroethylene copolymer, the polychlorotrifluoroethylene, or, the polyvinylidene fluoride is preferable.

The supply unit20circulates the target chemical liquid by using the first tube29aand the second tube29b, but the present invention is not limited to this, and a method of allowing the target chemical liquid to flow in one direction may be used. In this case, for example, a syringe pump can be used.

In a case where the target chemical liquid is circulated and supplied to the crystal oscillator27, the circulation flow rate of the target chemical liquid is preferably 0.01 to 1000 ml/s. In a case where the circulation flow rate is 0.01 to 1000 ml/s, a sufficient amount of impurities to be detected can be attached to the surface of the adsorption layer34.

In a case where the amount of increase in impurities in a case where the target chemical liquid is circulated for 1 hour is equal to or less than 1000 mass ppt, it is preferable because the measurement accuracy of purity does not decrease.

The disposition of the crystal oscillator sensor26in the flow cell unit12is not particularly limited.

[Management Method]

Next, a management method of managing the purity of the chemical liquid containing an organic solvent by sensing the impurities in the chemical liquid will be described.

The management method includes Step 1 of preparing a target chemical liquid containing an organic solvent, Step 2 of bringing a crystal oscillator sensor including an adsorption layer that adsorbs impurities (in a measuring device that senses impurities in the chemical liquid containing an organic solvent) and a crystal oscillator into the target chemical liquid and obtaining an amount of change in a resonance frequency of the crystal oscillator resulting from the contact of the target chemical liquid, and Step 3 of comparing whether or not the obtained amount of change in the resonance frequency falls within a permissible range of the amount of change in the resonance frequency based on a preset purity of the target chemical liquid to manage the purity of the chemical liquid.

As shown in the above-described measuring device10, in Step 2, at least a part of a liquid contact portion in the measuring device10coming into contact with the target chemical liquid is made of a fluorine-based resin.

In addition, in the management method, similar to the above-described measuring device, the target chemical liquid feeds the target chemical liquid to the crystal oscillator sensor and brings the target chemical liquid into contact with the crystal oscillator sensor. The target chemical liquid may be attached to the crystal oscillator sensor by causing the target chemical liquid to flow in one direction. Additionally, the target chemical liquid may be circulated and supplied to the crystal oscillator, and the circulation flow rate of the target chemical liquid may be 0.01 to 1000 ml/s.

Hereinafter, the management method will be described more specifically by taking the above-described measuring device10shown inFIG.1as an example. In the management method, for example, the target chemical liquid is circulated and supplied.

As described above, the target chemical liquid containing an organic solvent for managing the purity is prepared (Step 1), and the target chemical liquid is stored in the supply unit20of the measuring device10. The impurities are contained in the target chemical liquid.

Next, passing the target chemical liquid through the first tube29aand the supply passage40aof the block40from the supply unit20to the flow cell unit12to supply the target chemical liquid to the region44, passing the target chemical liquid through the discharge passage40bof the block40and the second tube29bto return the target chemical liquid to the supply unit20, and passing the target chemical liquid through the first tube29aand the supply passage40aof the block40again to supply the target chemical liquid the region44are carried out repeatedly. Accordingly, the target chemical liquid is circulated and supplied to the crystal oscillator27and brought into contact with the adsorption layer34of the crystal oscillator27.

A high-frequency signal of a sine wave is applied as a frequency signal from the oscillation unit14to the crystal oscillator sensor26, the crystal oscillator27is oscillated at a resonance frequency before the supply of the target chemical liquid, and resonance frequency before the supply of the target chemical liquid is obtained by the detection unit15. Thereafter, for example, after the target chemical liquid is supplied to the crystal oscillator27for a predetermined time, the detection unit15obtains the resonance frequency and then obtains the amount of change in the resonance frequency (Step 2). That is, the amount of change in the resonance frequency can be obtained by carrying out the method of measuring the chemical liquid having Step 1 and Step 2. The amount of change in the resonance frequency obtained by the detection unit15is output to the calculation unit16and stored in the calculation unit16.

The calculation unit16reads out the permissible range of the amount of change in the resonance frequency based on the preset purity of the target chemical liquid stored in the memory18, and compares the permissible range of the amount of change in the resonance frequency stored in the memory18with the amount of change in the resonance frequency obtained by the detection unit15to manage the purity of the chemical liquid (Step 3). For example, in a case where the amount of change in the resonance frequency is within the permissible range through the above-described comparison, the display unit23displays that the purity of the chemical liquid is within a permissible range. On the other hand, in a case where the amount of change in the resonance frequency exceeds the permissible range, the display unit23displays that the purity of the chemical liquid exceeds the permissible range.

In the management method, the purity of the chemical liquid can be easily obtained, and the purity of the target chemical liquid can be managed on the basis of the obtained purity. Accordingly, the quality of the chemical liquid can be managed.

In addition, the amount of change in the resonance frequency stored in the memory18and the permissible range thereof can be obtained on the basis of, for example, the calibration curve L shown inFIG.3as described above.

In addition, it is preferable that the above management method is carried out in a clean room. More specifically, it is preferable that the above management method is carried out in a clean room that satisfies the cleanliness of Class 2 or higher defined by the International Standard ISO 14644-1: 2015 established by the International Organization for Standardization.

[Other Examples of Crystal Oscillator Sensor]

FIG.5is a schematic diagram showing a second example of the crystal oscillator sensor according to the embodiment of the present invention, andFIG.6is a schematic cross-sectional view showing the second example of the crystal oscillator sensor according to the embodiment of the present invention.FIG.7is a schematic diagram showing a third example of the crystal oscillator sensor according to the embodiment of the present invention, andFIG.8is a schematic cross-sectional view showing the third example of the crystal oscillator sensor according to the embodiment of the present invention. In the crystal oscillator sensor26shown inFIGS.4to8, the same components as those of the crystal oscillator sensor26shown inFIG.2are designated by the same reference signs, and the detailed description thereof will be omitted.

The crystal oscillator sensor26shown inFIG.2has a configuration in which one electrode30is provided on the front surface27aof the crystal oscillator27, but the present invention is not limited to this. As shown inFIGS.5and6, the first electrode50and the second electrode51may be configured to be provided on the front surface27aof the crystal oscillator27. The first electrode50and the second electrode51are formed of, for example, a rectangular conductive layer, and are disposed parallel to each other at a distance. The first electrode50and the second electrode51are in a state of being electrically insulated from each other. The first adsorption layer35is provided on a surface50aof the first electrode50, and the second adsorption layer36is provided on a surface51aof the second electrode51.

The first electrode50and the electrode31are electrically connected to a first oscillation unit14a. The second electrode51and the electrode31are electrically connected to a second oscillation unit14b. The first oscillation unit14aand the second oscillation unit14bare provided in the oscillation unit14and can apply a high-frequency signal of a sine wave to the first electrode50and the electrode31and the second electrode51and the electrode31independently of each other as a frequency signal, thereby oscillating the crystal oscillator27at the resonance frequency.

Additionally, the first oscillation unit14aand the second oscillation unit14bare electrically connected to the detection unit15, respectively. The detection unit15has a switch unit (not shown) that switches the connection between the first oscillation unit14aand the second oscillation unit14b. The switch unit alternately takes the frequency signal of the first oscillation unit14aand the frequency signal of the second oscillation unit14binto the detection unit15. Accordingly, the detection unit15can independently obtain the resonance frequency of the first electrode50and the resonance frequency of the second electrode51.

The first adsorption layer35on the surface50aof the first electrode50and the second adsorption layer36on the surface51aof the second electrode51may be the same or different from each other. In a case where the first adsorption layer35and the second adsorption layer36are different from each other, a difference in resonance frequency between the first electrode50and the second electrode51can be used, and the purity can be easily estimated depending on whether or not the difference falls within the permissible range of the amount of change in the resonance frequency based on the preset purity of the target chemical liquid. Accordingly, the purity of the chemical liquid can be more easily obtained, the management of the purity becomes easy, and the quality of the chemical liquid can be easily managed. It is preferable that at least one of the first adsorption layer35or the second adsorption layer36is a Au layer. By forming the Au layer, one of the first electrode50and the second electrode51can be used as a reference electrode.

Additionally, as shown inFIGS.7and8, the electrode52may be configured to be provided on the front surface27aof the crystal oscillator27. The electrode52has a first electrode portion52a, a second electrode portion52b, and a connecting portion52cthat connects the first electrode portion52aand the second electrode portion52bto each other at one end. The first electrode portion52aand the second electrode portion52bare formed of, for example, a rectangular conductive layer, and are disposed parallel to each other at a distance. The first electrode portion52aand the second electrode portion52bare electrically connected to each other. The adsorption layer34is provided on the electrode52.

The first electrode portion52aand the electrode31are electrically connected to the first oscillation unit14a. The second electrode portion52band the electrode31are electrically connected to the second oscillation unit14b. The first oscillation unit14aand the second oscillation unit14bare provided in the oscillation unit14and can apply a high-frequency signal of a sine wave to the first electrode50and the electrode31and the second electrode51and the electrode31independently of each other as a frequency signal, thereby oscillating the crystal oscillator27at the resonance frequency.

Additionally, the first oscillation unit14aand the second oscillation unit14bare electrically connected to the detection unit15, respectively. The detection unit15has a switch unit (not shown) that switches the connection between the first oscillation unit14aand the second oscillation unit14b. The switch unit alternately takes the frequency signal of the first oscillation unit14aand the frequency signal of the second oscillation unit14binto the detection unit15. Accordingly, the detection unit15can independently obtain the resonance frequency of the first electrode portion52aand the resonance frequency of the second electrode portion52b.

Also in the crystal oscillator sensor26shown inFIG.8, the adsorption layers34are provided on the first electrode portion52aand the second electrode portion52b, but the adsorption layers may be different from each other on the first electrode portion52aand the second electrode portion52b. In a case where the adsorption layers are different, the purity can be easily estimated by using the difference in resonance frequency between the first electrode portion52aand the second electrode portion52b. Accordingly, the purity of the chemical liquid can be more easily obtained, the management of the purity becomes easy, and the quality of the chemical liquid can be easily managed. It is preferable to form a Au layer on at least one of the first electrode portion52aor the second electrode portion52b. By forming the Au layer, one of the first electrode portion52aand the second electrode portion52bcan be used as the reference electrode.

[Set]

As a method of indicating the quality of the chemical liquid, the quality of the chemical liquid can be easily managed by showing the purity measured by the above-described measuring device10or the like in association with the chemical liquid. The association between such a chemical liquid and the purity of the chemical liquid is referred to as a set.

The set has the chemical liquid and an information display unit that displays or stores resonance frequency information of the chemical liquid. By obtaining the amount of change in the resonance frequency of the crystal oscillator resulting from bringing the chemical liquid into contact with the crystal oscillator sensor including the adsorption layer that adsorbs the impurities in the chemical liquid and the crystal oscillator and comparing the obtained amount of change in the resonance frequency with the amount of change in the resonance frequency based on the preset purity of the chemical liquid, the evaluation of the purity of the chemical liquid is given with respect to the obtained amount of change in the resonance frequency. The resonance frequency information of the chemical liquid in which the amount of change in the obtained resonance frequency and the purity of the chemical liquid, which are based on the evaluation, are associated with each other and which is recorded as the resonance frequency information of the chemical liquid, is used to obtain information on the purity of the chemical liquid. The information on the purity of the chemical liquid can be obtained from the resonance frequency information of the chemical liquid.

In addition, the above-described evaluation is given by measuring the purity of the chemical liquid by using the above-described measuring device10.

Hereinafter, the set will be described more specifically.FIG.9is a schematic perspective view showing an example of the set of the embodiment of the present invention, andFIG.10is a schematic diagram showing an example of the information display unit of the set of the embodiment of the present invention.

As shown inFIG.9, a set60has, for example, a container64that stores the chemical liquid62in an inside64a. The container64has, for example, a cylindrical shape, and an information display unit66is provided on a side surface64b. In addition, the information display unit66may be provided on the upper surface64c. The information display unit66displays or stores the resonance frequency information of the chemical liquid.

As the information display unit66, for example, as shown inFIG.10, the resonance frequency information of the chemical liquid is indicated by using texts. However, the present invention is not limited to this, and at least one of texts, symbols, or barcodes can be used to display the resonance frequency information of the chemical liquid on the information display unit66. The barcodes are not particularly limited and may be secondary codes.

The information display unit66is not limited to the display by texts as shown inFIG.10and may be, for example, an information recording medium such as integrated circuit (IC) tags. In the case of the IC tags, the resonance frequency information of the chemical liquid can be read in a non-contact manner by using an IC tag reader. By using the barcodes or the IC tags as the information display unit66, the quality of the chemical liquid can be managed by using, for example, a reader.

The information display unit66on which the resonance frequency information of the chemical liquid is displayed by the output unit24can be obtained by the output unit24of the measuring device10.

The management method, the measuring method, the measuring device, the crystal oscillator sensor and the set of the present invention are basically configured as described above. Although the management method, the measuring method, the measuring device, the crystal oscillator sensor, and the set of the present invention have been described in detail above, the present invention is not limited to the above-described embodiment and it goes without saying that various improvements or changes may be made without departing from the scope of the present invention.

The target chemical liquid (hereinafter, also simply referred to as “chemical liquid”) used in the present invention contains an organic solvent.

In the present specification, the organic solvent is intended to be a liquid organic compound contained in a content exceeding 10,000 mass ppm per component with respect to the total mass of the chemical liquid. That is, in the present specification, the liquid organic compound contained in excess of 10,000 mass ppm with respect to the total mass of the chemical liquid corresponds to the organic solvent.

Additionally, in the present specification, the liquid means a liquid at 25° C. and under atmospheric pressure.

The content of the organic solvent in the chemical liquid is not particularly limited, but is 98.0% by mass or more is preferable, more preferably more 99.0% by mass, much more preferably 99.90% by mass or more, and particularly preferably more than 99.95% by mass, with respect to the total mass of the chemical liquid. The upper limit is less than 100% by mass.

As the organic solvent, one type may be used alone, or two or more types may be used. In a case where two or more types of organic solvents are used, it is preferable that the total content is within the above range.

The type of the organic solvent is not particularly limited, and a known organic solvent can be used. Examples of the organic solvent may include alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, lactic acid alkyl ester, alkyl alkoxypropionate, cyclic lactone (preferably a carbon number of 4 to 10), or monoketone compound (preferably a carbon number of 4 to 10) that may have a ring, alkylene carbonate, alkyl alkoxyacetate, alkyl pyruvate, dialkyl sulfoxide, cyclic sulfone, dialkyl ether, monohydric alcohol, glycol, alkyl acetate ester, N-alkylpyrrolidone, and the like.

Examples of the organic solvent include, preferably, one or more types selected from the group consisting of propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone (CHN), ethyl lactate (EL), propylene carbonate (PC), isopropanol (IPA), 4-methyl-2-pentanol (MIBC), butyl acetate (nBA), propylene glycol monoethyl ether, propylene glycol monopropyl ether, methyl methoxypropionate, cyclopentanone, γ-butyrolactone, diisoamyl ether, isoamyl acetate, dimethylsulfoxide, N-methylpyrrolidone, diethylene glycol, ethylene glycol, dipropylene glycol, propylene glycol, ethylene carbonate, sulfolane, cycloheptanone, and 2-heptanone.

Examples of using two or more types of organic solvents include the combined use of PGMEA and PGME, and the combined use of PGMEA and PC.

In addition, the type and content of the organic solvent in the chemical liquid can be measured by using a gas chromatograph mass spectrometer.

There is a case where the chemical liquid contains impurities other than the organic solvent. As described above, the resonance frequency changes as the impurities are adsorbed on the adsorption layer.

The impurities include metal impurities and organic impurities.

The metal impurities are intended as metal ions and metal impurities contained in a chemical liquid as a solid (elemental metal, particulate metal-containing compound, or the like).

The type of metal contained in the metal impurities is not particularly limited, and includes, for example, sodium (Na), potassium (K), calcium (Ca), iron (Fe), copper (Cu), magnesium (Mg), manganese (Mn), lithium (Li), aluminum (Al), chromium (Cr), nickel (Ni), titanium (Ti), and zirconium (Zn).

The metal impurities may be components that are inevitably contained in each component (raw material) contained in the chemical liquid, components that are inevitably contained during the manufacture, storage, and/or transfer of the chemical liquid, or may be added intentionally.

In a case where the chemical liquid contains the metal impurities, the content thereof is not particularly limited and may be 0.01 to 500 mass ppt with respect to the total mass of the chemical liquid.

In the present specification, the organic impurities are a compound different from the organic solvent which is a main component contained in the chemical liquid and is intended to be an organic substance contained in a content of 10,000 mass ppm or less with respect to the total mass of the chemical liquid. That is, in the present specification, the organic substance contained in the content of 10,000 mass ppm or less with respect to the total mass of the above-described chemical liquid corresponds to the organic impurities and does not correspond to the organic solvent.

In addition, in a case where the organic impurities including a plurality of types of compounds are contained in the chemical liquid and in a case where each compound corresponds to the above-described organic substance contained in a content of 10,000 mass ppm or less, each compound corresponds to the organic impurities.

In addition, water is not included in the organic impurities.

The organic impurities may be added to the chemical liquid or may be inevitably mixed in the chemical liquid in a producing process of the chemical liquid. Examples of cases in which the organic impurities are inevitably mixed in the producing process of the chemical liquid include a case where the organic impurities are contained in a raw material (for example, the organic solvent) used in the production of the chemical liquid, a case where mixing is performed in the producing process (for example, contamination) of the chemical liquid, or the like, but is not limited to the above.

The total content of organic impurities in the chemical liquid is not particularly limited and may be 0.1 to 5000 mass ppm with respect to the total mass of the chemical liquid.

As the organic impurities, one type may be used alone, or two or more types may be used in combination. In a case where two or more types of organic impurities are used in combination, the total content is preferably within the above range.

Examples of the organic impurities include dibutylhydroxytoluene (BHT), distearylthiodipropionate (DSTP), 4,4′-butylidenebis-(6-t-butyl-3-methylphenol), and 2,2′-methylenebis-(4-ethyl-6-t-butylphenol), and antioxidants such as the antioxidant described in JP2015-200775A; an unreacted raw material; a structural isomer and by-products produced during the production of the organic solvent; an eluent from members and the like constituting a production apparatus (for example, plasticizers eluted from a rubber member such as an O-ring) of the organic solvent; and the like.

The chemical liquid may contain water. The type of water is not particularly limited, and for example, distilled water, ion exchange water, and pure water can be used.

Water may be added to the chemical liquid or may be inevitably mixed in the chemical liquid in the producing process of the chemical liquid. Examples of cases in which the organic impurities are inevitably mixed in the producing process of the chemical liquid include a case where water is contained in a raw material (for example, the organic solvent) used in the production of the chemical liquid, a case where mixing is performed in the producing process (for example, contamination) of the chemical liquid, or the like.

The content of water in the chemical liquid is not particularly limited, but is generally preferably 2.0% by mass or less, more preferably 1.0% by mass or less, and much more preferably less than 0.5% by mass, with respect to the total mass of the chemical liquid.

In a case where the water content in the chemical liquid is 1.0% by mass or less, the manufacturing yield of semiconductor chips is more excellent.

In addition, the lower limit is not particularly limited but is about 0.01% by mass in many cases. In terms of production, it is difficult to keep the content of water below the above lower limit.

The method of preparing the above-described chemical liquid is not particularly limited, and examples thereof include a method of procuring an organic solvent through purchase and the like, and a method of reacting raw materials with each other to obtain an organic solvent. In addition, as the chemical liquid, it is preferable to prepare one having a small content of impurities as described above (for example, one having an organic solvent content of 99% by mass or more). Examples of commercially available products of such organic solvents include those referred to as “high-purity grade products”.

In addition, as necessary, the chemical liquid may be subjected to a purification treatment.

Examples of a purification method include distillation and filtration.

EXAMPLES

Hereinafter, the present invention will be described in more detail on the basis of examples. The materials, amounts used, ratios, treatment contents, treatment procedures, and the like shown in the following examples can be appropriately changed as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as limiting by the examples shown below.

Example A

[Production of Chemical Liquids]

First, the chemical liquids used in the examples described below were prepared. Specifically, first, high-purity grade organic solvent reagents having a purity of 99% by mass or more were purchased. After that, the purchased reagents are subjected to a filtration treatment in which the following filters are appropriately combined with each other to prepare chemical liquids (A1 to A20, B1 to B7, C1 to C5, D1 to D5, E1 to E7) having different amounts of impurities.IEX-PTFE (15 nm): 15 nm IEX PTFE made by Entegris.PTEE (12 nm): 12 nm PTFE made by Entegris.UPE (3 nm): 3 nm PE filter made by Entegris.

In addition, in order to adjust the amount of impurities in the chemical liquids described below, a purchase source of the organic solvent reagents was appropriately changed, the purity grade was changed, and the distillation treatment was carried out before the above filtration treatment.

[Evaluation Using Crystal Oscillator Sensor (1)]

A crystal oscillator sensor (refer toFIG.2) in which an Si layer is formed as an adsorption layer on an electrode portion was prepared, the crystal oscillator sensor was immersed in a chemical liquid shown in Table 1 described below for 60 minutes, and the amount of change (Hz) in the resonance frequency of a final crystal oscillator was obtained. In addition, the resonance frequency of the crystal oscillator before being immersed in the chemical liquid was 27 MHz.

The results are collectively shown in Table 1.

[Evaluation Using Surface Inspection Device (1)]

First, a silicon wafer having a diameter of about 300 mm (12 inches) was prepared.

Next, a surface inspection device (SP-5; made by KLA Tencor) was used to measure the number of defects present on the silicon wafer (this is defined as an initial value).

Next, by using the “CLEAN TRACK LITHIUS (product name)” made by Tokyo Electron Limited, each chemical liquid was rotationally applied onto the silicon wafer at 1500 rpm, and thereafter, the silicon wafer was spin-dried.

Next, the number of defects present on the silicon wafer after the application of the chemical liquid was measured (this is defined as a measurement value) by using the above surface inspection device. Next, the difference between the initial value and the measurement value (measurement value—initial value) was calculated and defined as the number of defects. The number of defects represents the amount of impurities in the chemical liquid remaining on the silicon wafer, and means that the smaller the numerical value, the smaller the amount of impurities in the chemical liquid.

The results are collectively shown in Table 1.

In addition, the above evaluation was performed in a clean room that satisfies the cleanliness of Class 2 or higher defined by the International Standard ISO 14644-1: 2015 established by the International Organization for Standardization.

In Table 1, the “Chemical Liquid” column represents a chemical liquid used in each example. For example, in Example 1, chemical liquids A1 to A20 containing nBA (butyl acetate) are used, and the amount of impurities differs between the chemical liquids A1 to A20.

The symbols of the chemical liquids in Table 1 represent the following chemical liquids.

nBA: Butyl acetate

MIBC: 4-methyl-2-pentanol

PGMEA: Propylene Glycol Monomethyl Ether Acetate

IPA: Isopropanol

CHN: Cyclohexanone

TABLE 1Chemical liquidQuartz oscillatorSurfaceType ofsensor evaluationinspectionorganic(resonance frequencydevice (numbersolventNo.change amount (Hz))of defects)Example1nBAA1466810A2510210A31041143A41576179A52125386A624425145A713352123A8365314A9491259A10566140A11429419A1284815A131824679A1418894103A15962867A16369413A17257814A1853856457A19105569890A20551301025ExampleMIBCB1482362B2825513B310954179B4677978B541395B660318B7624518ExamplePGMEAC15311183C2468811C3367910C434505C523010235ExampleIPAD1410654894D221285458D327562D429206D5132975ExampleCHNE1239011895E213426131E3106408E418649154E510780107E628496E719874

As shown in Table 1, there is a correlation between the amount of change in the resonance frequency and the number of defects, and in a case where the amount of change in the resonance frequency is large, the number of defects tends to increase.

Additionally, as shown inFIG.3, in a case where points for the amounts of change (crystal oscillator sensor evaluation (resonance frequency change amount (Hz))) in the resonance frequency of all the chemical liquids and the number of defects (surface inspection device evaluation (number of defects)) in Examples 1 to 5 were plotted on rectangular coordinates with the amount of change in the resonance frequency on the horizontal axis and the number of defects on the vertical axis, and a calibration curve passing through the plotted points was created by the least square method to calculate a determination coefficient (R2) was calculated, the determination coefficient was calculated as 0.8004 (refer toFIG.11). The closer the determination coefficient is to 1.000, the better the results, but the results in Table 1 show that the correlation between the amount of change in the resonance frequency and the number of defects is high.

Additionally, in a case where the [Evaluation using crystal oscillator sensor (1)] was carried out, the amount of change in the resonance frequency was measured according to the same procedure as in the above Examples 1 to 5 except that the evaluation was performed in a clean room that satisfies the cleanliness of Class 2 or higher defined by the International Standard ISO 14644-1: 2015 established by the International Organization for Standardization and the evaluation was performed by adjusting the temperature of the chemical liquid to 23° C.

Table 2 shows the obtained results of the amount of change in the resonance frequency and the [Evaluation using surface inspection device] obtained above.

TABLE 2Chemical liquidQuartz oscillatorSurfaceType ofsensor evaluationinspectionorganic(resonance frequencydevice (numbersolventNo.change amount (Hz))of defects)ExamplenBAA12013106nBAA2165510nBAA3244743nBAA4696379nBAA5779886nBAA612456145nBAA710970123nBAA8138214nBAA9127159nBAA10264140nBAA11202019nBAA1212735nBAA13620779nBAA1411039103nBAA15685567nBAA16177313nBAA1792114nBAA1824657457nBAA1952199890nBAA20523701025ExampleMIBCB1176067MIBCB2206313MIBCB35192179MIBCB4476178MIBCB510175MIBCB621218MIBCB7291018ExamplePGMEAC12336188PGMEAC2197611PGMEAC3171210PGMEAC49675PGMEAC521483235ExampleIPAD1205274899IPAD219537458IPAD37482IPAD410076IPAD59135ExampleCHNE11138418910CHNE211517131CHNE39098CHNE48731154CHNE58918107CHNE68626CHNE79874

In a case where points for the amounts of change (crystal oscillator sensor evaluation (resonance frequency change amount (Hz))) in the resonance frequency of all the chemical liquids and the number of defects (surface inspection device evaluation (number of defects)) in Examples 6 to 10 were plotted on rectangular coordinates with the amount of change in the resonance frequency on the horizontal axis and the number of defects on the vertical axis, and a calibration curve passing through the plotted points was created by the least square method to calculate a determination coefficient (R2) was calculated, the determination coefficient was calculated as 0.9626. The results in Table 2 were better than the results in Table 1.

Example B

According to the same procedure as in the above Example A, the chemical liquids (A21 to A40, B8 to B14, C6 to C10, D6 to D10, E8 to E14) used in the respective examples were prepared. In addition, the amount of impurities in each chemical liquid was different. For the impurity concentration in the chemical liquid, the peaks of all components of the chemical liquid except a main chemical liquid were obtained as integral values by LC/MS, and the concentration was obtained through n-hexane conversion.

[Evaluation Using Crystal Oscillator Sensor (2)]

The evaluation of the amount of change in the resonance frequency of the crystal oscillator was carried out by preparing a crystal oscillator sensor in which the adsorption layer shown inFIG.2is each layer (Si layer, SiO2layer, SiOC layer, Cu layer, Co layer, Ti layer, W layer, TiN layer, Ta layer, TaN layer) shown in Table 3 and bringing each chemical liquid (A21 to A40, B8 to B14, C6 to C10, D6 to D10, E8 to E14) into contact with the crystal oscillator sensor by using the measuring device (refer toFIG.1) having the flow cell unit, shown inFIG.4, having the above crystal oscillator sensor. Specifically, the temperature of the chemical liquid was adjusted by a temperature adjustment unit such that the temperature of the chemical liquid is 23° C., and the amount of change (Hz) in the resonance frequency of the crystal oscillator in a case where each chemical liquid was circulated in the flow cell unit at a circulation flow rate of 20 ml/s for 60 minutes was obtained. In addition, the resonance frequency of the crystal oscillator before being brought into contact with the chemical liquid was 27 MHz.

The results are collectively shown in Tables 3 to 7.

In addition, the above evaluation was performed in a clean room that satisfies the cleanliness of Class 2 or higher defined by the International Standard ISO 14644-1: 2015 established by the International Organization for Standardization.

Additionally, the liquid contact portions (the liquid contact portion of the block, the liquid contact portion of the seal portion, and the liquid contact portion of the liquid feeding unit) of the respective members of the flow cell unit in the resonance frequency measuring device are made of the same fluorine-based resin as in Example 24 described below.

[Evaluation Using Surface Inspection Device (2)]

First, various substrates (Si substrate, SiO2substrate, SiOC substrate, Cu substrate, Co substrate, Ti substrate, W substrate, TiN substrate, Ta substrate, and TaN substrate) were prepared.

Next, the surface inspection device (SP-5; made by KLA Tencor) on the wafer was used to measure the number of defects present on each substrate (this is defined as the initial value).

Next, by using the “CLEAN TRACK LITHIUS (product name)” made by Tokyo Electron Limited, each chemical liquid (A21 to A40, B8 to B14, C6 to C10, D6 to D10, E8 to E14) was rotated and applied onto the substrate at 1500 rpm, and thereafter, the substrate was spin-dried.

Next, the number of defects present on the substrate after the application of the chemical liquid was measured (this is defined as a measurement value) by using the above device (SP-5). Next, the difference between the initial value and the measurement value (measurement value—initial value) was calculated and defined as the number of defects.

The results are collectively shown in Tables 3 to 7.

In addition, the above evaluation was performed in a clean room that satisfies the cleanliness of Class 2 or higher defined by the International Standard ISO 14644-1: 2015 established by the International Organization for Standardization.

In Tables 3 to 7, the results using adsorption layers and substrates of the same metal types are shown side by side. For example, in the “Si” column in Table 3, the results of [Evaluation using crystal oscillator sensor (2)] using an “Si layer” as an adsorption layer and the results of the [Evaluation using surface inspection device (2)] using Si substrate] are shown.

TABLE 3SiSiO2Quartz oscillatorQuartz oscillatorsensor evaluationSurfacesensor evaluationSurfaceChemical liquid(resonanceinspection(resonanceinspectionType offrequency changedevicefrequency changedeviceorganicamount(numberamount(numbersolventNo.(Hz))of defects)(Hz))of defects)ExamplenBAA21994102292511nBAA2210191023525nBAA23636814720nBAA2418112341857nBAA255152861189215nBAA26264644611110nBAA2798101562264390nBAA2811591426836nBAA2922345111nBAA305900401362100nBAA3115931936848nBAA3242759913nBAA338461019526nBAA34502611616nBAA3512581329031nBAA36805818620nBAA3714311833045nBAA3811571426736nBAA3941159511nBAA40487511214ExampleMIBCB83314761012MIBCB9518681025119692563MIBCB105361631237158MIBCB115678671310167MIBCB1211771327233MIBCB13595713717MIBCB1432667514ExamplePGMEAC6438778101219513PGMEAC737458612PGMEAC8643814821PGMEAC914791834145PGMEAC109051120927ExampleIPAD61071102472414IPAD7641514813IPAD832647511IPAD9193713584470895IPAD101672386ExampleCHNE858261341615CHNE942659813CHNE10108971722515430CHNE11619814319CHNE122903678CHNE1384421451948363CHNE14476611015

TABLE 4SiOCCuQuartz oscillatorQuartz oscillatorsensor evaluationSurfacesensor evaluationSurfaceChemical liquid(resonanceinspection(resonanceinspectionType offrequency changedevicefrequency changedeviceorganicamount(numberamount(numbersolventNo.(Hz))of defects)(Hz))of defects)ExamplenBAA215527224821611nBAA2256674255222nBAA2335358159173nBAA241006164453492nBAA25286262312881868nBAA261470320661959nBAA275450113124533393nBAA28644105290315nBAA29124325697nBAA3032782901475870nBAA31885139398417nBAA3223737107112nBAA3347076212227nBAA3427945126135nBAA3569991314274nBAA3644758201175nBAA37795130358389nBAA38643105289315nBAA392283310399nBAA4027039122118ExampleMIBCB818429838712MIBCB92881574311296722294MIBCB10297845713401372MIBCB11315448414191453MIBCB1265495294285MIBCB1333148149144MIBCB141814282126ExamplePGMEAC624375651097169613PGMEAC72083594105PGMEAC835760161180PGMEAC9821129370387PGMEAC1050379226237ExampleIPAD65957126821214IPAD735639160117IPAD8181328295IPAD910761259648437787IPAD1093174252ExampleCHNE83234714514115CHNE923737106112CHNE106054124727243741CHNE1134456155168CHNE12161237270CHNE134690105121103154CHNE1426444119131

TABLE 5CoTiQuartz oscillatorQuartz oscillatorsensor evaluationSurfacesensor evaluationSurfaceChemical liquid(resonanceinspection(resonanceinspectionType offrequency changedevicefrequency changedeviceorganicamount(numberamount(numbersolventNo.(Hz))of defects)(Hz))of defects)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

TABLE 6WTiNQuartz oscillatorQuartz oscillatorsensor evaluationSurfacesensor evaluationSurfaceChemical liquid(resonanceinspection(resonanceinspectionType offrequency changedevicefrequency changedeviceorganicamount(numberamount(numbersolventNo.(Hz))of defects)(Hz))of defects)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

TABLE 7TaTaNQuartz oscillatorQuartz oscillatorsensor evaluationSurfacesensor evaluationSurfaceChemical liquid(resonanceinspection(resonanceinspectionType offrequency changedevicefrequency changedeviceorganicamount(numberamount(numbersolventNo.(Hz))of defects)(Hz))of defects)ExamplenBAA2122152917253911nBAA22226542176553nBAA23141423110431nBAA2440312043131228nBAA25114545678924658nBAA2658823454582392nBAA272180829716988463nBAA28258771201786nBAA295023739242nBAA301311212710212170nBAA3135410212761041nBAA329527474279nBAA33188556146567nBAA3411233087336nBAA35280669218682nBAA36179428139437nBAA37318951248970nBAA38257769200784nBAA399124371248nBAA4010828884293ExampleMIBCB8742125721612MIBCB91152654515897755605MIBCB10119133549283422MIBCB11126235539833624MIBCB12262696204710MIBCB13132352103359MIBCB147230856315ExamplePGMEAC69754148759423113PGMEAC78325665261PGMEAC8143439111448PGMEAC9329947256966PGMEAC10201580157591ExampleIPAD623851818552814IPAD7142287111293IPAD87223156236IPAD9430519040335319421IPAD103712729129ExampleCHNE812934410135115CHNE99527374278CHNE102422914818869331CHNE11138412107420CHNE126417150175CHNE131876771214617866CHNE1410632282328

As shown in the above tables, in a case where the adsorption layers and the substrates made of the same metal types were used, the amount of change in the resonance frequency and the number of defects have a high correlation, and in a case where the amount of change in the resonance frequency is large, the number of defects tended to increase.

Example C

The amount of change in the resonance frequency was measured according to the same procedure as in [Evaluation using crystal oscillator sensor (2)] except that a Au layer was used instead of the Si layer.

Next, the amount of change in the resonance frequency obtained by using the Au layer was subtracted from the amount of change in the resonance frequency obtained by using the Si layer, and the difference was obtained.

The results are shown in Table 8.

In Table 8, the “Si layer-Au layer” column represents the difference obtained by subtracting the “Crystal oscillator sensor evaluation” in the “Au layer” column (Resonance frequency change amount (Hz))“from the “Crystal oscillator sensor evaluation (resonance frequency change amount (Hz))” in the “Si layer” column.

TABLE 8Si layerAu layerQuartz oscillatorQuartz oscillatorsensor evaluationSurfacesensor evaluationChemical liquid(resonanceinspection(resonanceFrequency-Type offrequency changedevicefrequency changeOscillationorganicamount(numberamountfrequencysolventNo.(Hz))of defects)(Hz))Si layer-Au 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

In a case where points for the amounts of change (crystal oscillator sensor evaluation (resonance frequency change amount (Hz))) in the resonance frequency of the “Si layer” column and the number of defects (surface inspection device evaluation (number of defects)) in Examples 16 to 20 were plotted on rectangular coordinates with the amount of change in the resonance frequency on the horizontal axis and the number of defects on the vertical axis, and a calibration curve passing through the plotted points was created by the least square method to calculate a determination coefficient (R2) was calculated, the determination coefficient was calculated as 0.9915.

Additionally, in a case where the points for the difference in the amount of change in the resonance frequency in the “Si layer-Au layer” column in Examples 16 to 20 and the number of defects (surface inspection device evaluation (number of defects)) in the “Si layer” column were plotted, and a calibration curve passing through the plotted points was created by the least square method to calculate the determination coefficient (R2), the determination coefficient was calculated as 0.996.

From the above results, it was confirmed that in a case where the Au layer was used as a reference, the amount of change in the resonance frequency and the number of defects have a higher correlation.

Example D

The chemical liquids (A41 to A140) used in the respective examples were prepared according to the same procedure as in Example A.

The evaluation of the amount of change in the resonance frequency of the crystal oscillator was carried out by preparing a crystal oscillator sensor in which the adsorption layer shown inFIG.2is an Si layer and bringing each chemical liquid (A41 to A140) into contact with the crystal oscillator sensor by using the measuring device (refer toFIG.1) having the flow cell unit, shown inFIG.4, having the above crystal oscillator sensor. Specifically, the temperature of the chemical liquid was adjusted by a temperature adjustment unit such that the temperature of the chemical liquid is 23° C., and the amount of change (Hz) in the resonance frequency of the crystal oscillator in a case where each chemical liquid was circulated in the flow cell unit at a circulation flow rate of 20 ml/s for 60 minutes was obtained. In addition, the resonance frequency of the crystal oscillator before being brought into contact with the chemical liquid was 27 MHz.

In addition, in the measuring device used, at least a part of the liquid contact portion was made of the fluorine-based resin.

Specifically, in a case of the liquid contact portion (the portion coming into contact with the target chemical liquid) of the block, shown inFIG.4, of the flow cell unit is made of the perfluoroethylene propene copolymer (FEP, Tensile strength: 20 to 30 MPa, Shore D hardness: 60 to 65, Bending modulus: 0.55 to 0.67 GPa), the “flow cell” column in Tables 9 to 10 is marked as “Yes”, and in a case where the liquid contact portion is not made of the fluorine-based resin, the column is marked as “-”.

Additionally, in a case where the liquid contact portion (the portion coming into contact with the target chemical liquid) of the liquid feeding unit is made of the THV soft fluororesin, the “liquid feeding unit” column in Tables 9 to 10 is marked as “Yes”, and in a case where the liquid contact portion is not made of the fluorine-based resin, the column is marked as “-”.

Additionally, in a case where the liquid contact portion (the portion coming into contact with the target chemical liquid) of the seal portion, shown inFIG.4, which holds the target chemical liquid in the region, is made of polyvinylidene fluoride (PVDF, Tensile strength: 30 to 60 MPa, Shore D hardness: 64 to 79), the “seal portion A” column in Tables 9 to 10 is marked as “Yes”, and in a case where the liquid contact portion is not made of the above-described fluorine-based resin, the column is marked as “-”.

Moreover, in a case where the liquid contact portion (the portion coming into contact with the target chemical liquid) of the seal portion, shown inFIG.4, which holds the target chemical liquid in the region, is made of perfluoroalkoxyalkane (PFA, Tensile strength: 25 to 35 MPa, Shore D hardness: 62 to 66), the “Seal portion B” column in Tables 9 to 10 is marked as “Yes”, and in a case where the liquid contact portion of the seal portion is not made of the fluorine-based resin, the column is marked as “-”.

Additionally, in a case where the amount of change in the resonance frequency was measured, the amount of impurities eluted from the measuring device into the target chemical liquid was measured using LC/MS (Thermo LC/MS QE plus).

TABLE 9Quartz oscillatorsensor evaluationSurfaceChemical liquidAmount of(resonanceinspectionType ofLiquidSealingSealingelution offrequency changedeviceorganicFlowfeedingportionportionimpuritiesamount(numbersolventNo.cellunitAB(ppt)(Hz))of defects)ExamplenBAA41Yes———81046681021A42Yes———810510210A43Yes———8101241143A44Yes———8101576179A45Yes———8102125386A46Yes———81024425145A47Yes———81013352123A48Yes———810365314A49Yes———810791259A50Yes———810566140A51Yes———810899419A52Yes———81084815A53Yes———8101824679A54Yes———81018894103A55Yes———810962867A56Yes———810369413A57Yes———810257814A58Yes———81063856457A59Yes———810115569890A60Yes———810481301025ExamplenBAA61YesYes——65046681022A62YesYes——650510210A63YesYes——6501041143A64YesYes——6501576179A65YesYes——6502125386A66YesYes——65024425145A67YesYes——65013352123A68YesYes——650365314A69YesYes——650491259A70YesYes——650566140A71YesYes——650429419A72YesYes——65084815A73YesYes——6501824679A74YesYes——65018894103A75YesYes——650962867A76YesYes——650369413A77YesYes——650257814A78YesYes——65053856457A79YesYes——650105569890A80YesYes——650551301025ExamplenBAA81YesYesYes—31020131023A82YesYesYes—310165510A83YesYesYes—31024478A84YesYesYes—310696379A85YesYesYes—310779886A86YesYesYes—31012456145A87YesYesYes—31010970123A88YesYesYes—310138214A89YesYesYes—31012714A90YesYesYes—310264140A91YesYesYes—310202019A92YesYesYes—31012735A93YesYesYes—310620779A94YesYesYes—31011039103A95YesYesYes—310685567A96YesYesYes—310177313A97YesYesYes—3109217A98YesYesYes—3106576A99YesYesYes—31052199890A100YesYesYes—310523701025

TABLE 10Quartz oscillatorsensor evaluationSurfaceChemical liquidAmount of(resonanceinspectionType ofLiquidSealingSealingelution offrequency changedeviceorganicFlowfeedingportionportionimpuritiesamount(numbersolventNo.cellunitAB(ppt)(Hz))of defects)ExamplenBAA101YesYes—Yes<509941024A102YesYes—Yes<50101910A103YesYes—Yes<506368A104YesYes—Yes<50181123A105YesYes—Yes<50515286A106YesYes—Yes<50264644A107YesYes—Yes<509810156A108YesYes—Yes<50115914A109YesYes—Yes<502234A110YesYes—Yes<50295040A111YesYes—Yes<50159319A112YesYes—Yes<504275A113YesYes—Yes<5084610A114YesYes—Yes<505026A115YesYes—Yes<50125813A116YesYes—Yes<508058A117YesYes—Yes<50143118A118YesYes—Yes<50115714A119YesYes—Yes<504115A120YesYes—Yes<504875ExamplenBAA121————1280156801025A122————1280247510A123————12801241143A124————12801576179A125————12802125386A126————12809102145A127————128028970123A128————1280365314A129————1280217959A130————1280566140A131————1280899419A132————128084815A133————12801824679A134————12806789103A135————1280962867A136————1280369413A137————1280257814A138————1280105789457A139————128056790890A140————1280243791025

As shown in the above Tables 9 and 10, in Examples 21 to 24 in which at least a part of the liquid contact portion with the target chemical liquid in the measuring device is made of the fluorine-based resin, it was confirmed that, compared to Example 25 in where the fluorine-based resin is not used, the amount of impurities eluted from the measuring device is smaller, and as a result, the correlation between the amount of change in the resonance frequency and the number of defects is higher.

In a case where points for the amounts of change (crystal oscillator sensor evaluation (resonance frequency change amount (Hz))) in the resonance frequency and the number of defects (surface inspection device evaluation (number of defects)) in Example 21 were plotted on rectangular coordinates with the amount of change in the resonance frequency on the horizontal axis and the number of defects on the vertical axis, and a calibration curve passing through the plotted points was created by the least square method to calculate a determination coefficient (R2) was calculated, the determination coefficient was calculated as 0.7318. In a case where the determination coefficients were calculated for Examples 22 to 25, the determination coefficients were 0.8086, 0.9843, 0.9936, and 0.3297, respectively. From this result, it was confirmed that the correlation between Examples 21 to 24, in which at least a part of the liquid contact portion of the measuring device is made of the fluorine-based resin, shows a better correlation than that of Example 25 in which the liquid contact portion of the measuring device is not made of the fluorine-based resin.

In Example 23, in a case where the resin constituting the liquid contact portion (the portion coming into contact with the target chemical liquid) of the block, shown inFIG.4, of the flow cell unit is changed from the perfluoroethylene propene copolymer to the perfluoroalkoxyalkane, the ethylene tetrafluoroethylene copolymer, the perfluoroethylene propene copolymer, the polychlorotrifluoroethylene, or the polyvinylidene fluoride, it was confirmed that all show a correlation exceeding a correlation coefficient of 0.95. However, these results were slightly inferior to the result (0.984) of Example 23.

Additionally, in Example 23, in a case where the resin constituting the liquid contact portion (the portion coming into contact with the target chemical liquid) of the liquid feeding unit is changed from the THV soft fluororesin to the polyvinylidene fluoride, the ethylene tetrafluoroethylene copolymer, or the polychlorotrifluoroethylene, it was confirmed that all show a correlation exceeding a correlation coefficient of 0.95. However, these results were slightly inferior to the result (0.984) of Example 23.

Additionally, in Example 23, in a case where the resin constituting the liquid contact portion (the portion coming into contact with the target chemical liquid) of the seal portion, shown inFIG.4, which holds the target chemical liquid in the region is changed from the polyvinylidene fluoride to the perfluoroethylene propene copolymer, the ethylene chlorotrifluoroethylene copolymer, the ethylene tetrafluoroethylene copolymer, or the polychlorotrifluoroethylene, it was confirmed that all show a correlation exceeding a correlation coefficient of 0.95. However, these results were slightly inferior to the result (0.984) of Example 23.

Additionally, in Example 23, in a case where any of the resin constituting the liquid contact portion (the portion coming into contact with the target chemical liquid) of the block, shown inFIG.4, of the flow cell unit, the resin constituting the liquid contact portion (the portion coming into contact with the target chemical liquid) of the liquid feeding unit, and the resin constituting the liquid contact portion (the portion coming into contact with the target chemical liquid) of the seal portion, shown inFIG.4, which holds the target chemical liquid in the region, is changed to the polytetrafluoroethylene, a value having a correlation coefficient larger than 0.85 and less than 0.95 value was obtained. From these results, it was confirmed that a better effect can be obtained in a case where the resin is used as the resin constituting the liquid contact portion with a fluorine-based resin other than the above-described polytetrafluoroethylene.

In addition, in a case where all the resin constituting the liquid contact portion (the portion coming into contact with the target chemical liquid) of the block, shown inFIG.4, of the flow cell unit, the resin constituting the liquid contact portion (the portion coming into contact with the target chemical liquid) of the liquid feeding unit, and the resin constituting the liquid contact portion (the portion coming into contact with the target chemical liquid) of the seal portion, shown inFIG.4, that holds the target chemical liquid in the region are the polytetrafluoroethylene, the correlation coefficient is superior to that of Example 22 but was equal to or less than 0.85.

Example E

[Production of Chemical Liquids]

nBA of high-purity grade having a purity of 99% by mass or more was purchased, and the following filters were appropriately combined with each other and subjected to the filtration treatment to prepare two types of chemical liquids (chemical liquid X and chemical liquid Y) having different amounts of impurities.IEX-PTFE (15 nm): 15 nm IEX PTFE made by Entegris.PTEE (12 nm): 12 nm PTFE made by Entegris.UPE (3 nm): 3 nm PE filter made by Entegris.

Next, a case where the amount of change in the resonance frequency is equal to or less than 2000 Hz was set as a permissible range from the rectangular coordinates data with the amount of change in the resonance frequency obtained from the results of the amount of change in the resonance frequency (crystal oscillator sensor evaluation (resonance frequency change amount (Hz))) and the number of defects (surface inspection device evaluation (number of defects)) in Example 24 of the above <Example D> on the horizontal axis and the number of defects on the vertical axis.

Next, the “Crystal oscillator sensor evaluation (resonance frequency change amount (Hz))” was obtained according to the same procedure as in Example 24 by using the chemical liquid X and the chemical liquid Y.

After that, in a case where the permissible range (2000 Hz or less) of the amount of change in the resonance frequency preset above was set in the memory of the measuring device, and whether the amount of change in the resonance frequency obtained by using the chemical liquid X and the chemical liquid Y is within the permissible range was determined by the calculation unit, the chemical liquid X is within the permissible range, and the chemical liquid Y is out of the permissible range.

In a case where the [Evaluation using surface inspection device (1)] carried out in <Example A> was carried out using the chemical liquid X and the chemical liquid Y, it was confirmed that the number of defects in the chemical liquid X is about 20 or less, and the number of defects is small, whereas the number of defects in the chemical liquid Y is more than 20, and the number of defects is large. From this result, it was confirmed that the purity of the chemical liquid can be managed by measuring the amount of change in the resonance frequency of the chemical liquid.

Explanation of References

10: measuring device12: flow cell unit14: oscillation unit14a: first oscillation unit14b: second oscillation unit15: detection unit16: calculation unit20: supply unit18: memory22: control unit26: crystal oscillator sensor27: crystal oscillator27a: front surface27b: back surface28: temperature adjustment unit29a: first tube29b: second tube30: electrode30a: surface31: electrode34: adsorption layer40: block40a: supply passage40b: discharge passage40c,42a: face42,43: seal portion44: region45: region50: first electrode51: second electrode52: electrode52a: first electrode portion52b: second electrode portion52c: connecting portion60: set62: chemical liquid64: container64a: inside64b: side surface64c: upper surface66: information display unit