Aerosol flow formation device, particle property measurement device, and particle property measurement method

Abstract

Provided is an aerosol flow formation device that forms an aerosol flow from a volatile liquid containing non-volatile impurities, said device comprising: a pipe body; an injection part that is installed at or near the central axis of the pipe body and injects the volatile liquid to form a mist flow; and a heating part that heats a prescribed region of the pipe body in the central axis direction and vaporizes the volatile liquid contained in the mist flow to form an aerosol flow. The pipe body has an inverted taper shape in a region between the downstream end of the injection part and the upstream end of the prescribed region, the inverted taper shape being formed due to the inner wall in a region, which is at least half of the region from the downstream end of a region in which the mist flow spreads and flows, having an opening diameter that increases toward the downstream side. In the prescribed region, the opening diameter in a region that is greater than half of the region from the upstream end is substantially the same.

Description

Aerosol flow forming device, particle property measuring device, and particle property measuring method

[0001] The present invention relates to an apparatus for forming an aerosol flow from a volatile liquid containing non-volatile impurities, and an apparatus and method for measuring the particle properties of non-volatile impurities contained in a volatile liquid.

[0002] In the manufacturing process of semiconductor devices, various organic chemicals are used as various semiconductor processing liquids such as developers, etching liquids, stripping liquids, cleaning liquids, etc. Isopropyl alcohol, which is an organic chemical, is widely used as a developer or cleaning liquid.

[0003] Here, if nonvolatile impurities are contained in the organic chemical solution, they can cause various defects, reducing product yield and reliability. For this reason, organic chemical solutions are required to be highly pure. As products have become more dense due to the remarkable development of the electronics industry in recent years, the requirement for high purity has become even stricter. In particular, the residue remaining after drying isopropyl alcohol is a major cause of defects and is a major problem, so the requirement for high purity is extremely high.

[0004] Patent Document 1 describes a method for measuring particles in liquid. After generating droplets from a liquid to be measured, the liquid is removed from the droplets, exposing solid matter contained in the droplets, and the dissolved matter in the droplets solidifies, thereby generating a particle group. Next, a differential mobility analyzer (DMA) is used to apply an electric field to the particle group to extract particles having a predetermined particle size or a predetermined particle size range, and then a condensation particle counter (CPC) is used to count the number of extracted particles.

[0005] JP 2012-37318 A

[0006] Here, the method of measuring the particle properties of nonvolatile impurities derived from organic chemical solutions using DMA and CPC is extremely useful because it allows for high-resolution analysis of the particle properties of nonvolatile impurities that remain as residues when organic chemical solutions are dried.

[0007] On the other hand, a liquid particle counter (LPC), which is widely used as a method for measuring the number of particles contained in a liquid, has a detectable particle size lower limit of about 20 nm. That is, when using an LPC, particles with a particle size of less than 20 nm are usually not detected. However, in the application of semiconductor processing solutions, as products become more dense, the demand for higher purity increases, and there is a need to remove non-volatile impurities with a particle size of less than 20 nm. LPC has not been able to adequately meet this demand.

[0008] Similarly, single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is known as a method for analyzing inorganic particles. However, even with SP-ICP-MS, it has been difficult to stably analyze particles with a particle size of less than 20 nm. Furthermore, while ICP can detect inorganic particles with high sensitivity, it cannot detect organic particles.

[0009] In response to this situation, the use of DMA and CPC has the advantage of being able to detect particles with a particle diameter of less than 20 nm, specifically particles with a particle diameter of approximately 1 nm to 3 nm. However, when using DMA and CPC to measure the particle properties of nonvolatile impurities derived from organic chemical solutions, it has been discovered that nonvolatile impurities may be lost when an aerosol flow is formed. As a result, the detection sensitivity of DMA and CPC may not be fully utilized, or stable measurement results may not be obtained, leaving room for improvement.

[0010] An object of the present invention is to provide an aerosol flow forming device that can suppress the loss of non-volatile impurities.

[0011] An aerosol flow forming device according to one aspect of the present invention is a device for forming an aerosol flow from a volatile liquid containing non-volatile impurities, and comprises a tubular body, an injection unit installed on or near the central axis of the tubular body and injecting the volatile liquid to form a mist flow, and a heating unit that heats a predetermined region in the central axis direction of the tubular body and vaporizes the volatile liquid contained in the mist flow to form an aerosol flow, and the tubular body has an inner wall surface in a region between the downstream end of the injection unit and the upstream end of the predetermined region, in a region that is more than half the region from the downstream end of the region where the mist flow spreads as it flows, with a reverse tapered shape in which the diameter increases toward the downstream side, and the diameter of the region in the predetermined region that is more than half the region from the upstream end is approximately the same.

[0012] According to the present invention, it is possible to provide an aerosol flow forming device that can suppress the loss of non-volatile impurities.

[0013] Fig. 2 is a cross-sectional view showing an example of an aerosol flow forming device according to an embodiment of the present invention. Fig. 3 is a side view showing another example of the tubular body of Fig. 1. Fig. 4 is a side view showing another example of the tubular body of Fig. 1. Fig. 5 is a side view showing another example of the tubular body of Fig. 1. Fig. 6 is a schematic view showing an example of a particle property measuring device according to an embodiment of the present invention. Fig. 7 is a schematic view showing a method for measuring the spread angle of a mist flow.

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0015] (Aerosol flow generating device) The aerosol flow generating device of this embodiment is a device that generates an aerosol flow from a volatile liquid containing non-volatile impurities. The aerosol flow generating device of this embodiment includes a tubular body, an injection unit installed on or near the central axis of the tubular body and injecting a volatile liquid to form a mist flow, and a heating unit that heats a predetermined region along the central axis of the tubular body and vaporizes the volatile liquid contained in the mist flow to form an aerosol flow. Furthermore, the tubular body has an inner wall surface in a region between the downstream end of the injection unit and the upstream end of the predetermined region, the inner wall surface of which extends from the downstream end of the region where the mist flow spreads and flows, and has an inverse tapered shape with a diameter that increases toward the downstream side. Furthermore, the tubular body has an inner diameter that is approximately the same in a region exceeding half of the upstream end of the predetermined region. The aerosol flow generating device of this embodiment is used, for example, to measure the particle properties of non-volatile impurities contained in an aerosol flow.

[0016] In this specification and claims, the region where the mist flow spreads means a region where the mist flow maintains a spreading angle, which will be described later.

[0017] [Volatile Liquid] The volatile liquid is not particularly limited as long as it contains non-volatile impurities and can form an aerosol. The volatile liquid is used, for example, to measure the particle properties of non-volatile impurities. As the volatile liquid, water quality measurement liquids used in environmental tests, aqueous chemicals such as hydrogen peroxide solution, hydrochloric acid, and ammonia water, and ultrapure water can also be used effectively. However, since high purity is required, it is preferable to use a semiconductor processing liquid, and since the requirement for high purity is particularly high, it is particularly preferable to use a developer or a cleaning liquid.

[0018] The boiling point of the volatile liquid is preferably 40° C. or higher and 130° C. or lower, and more preferably 50° C. or higher and 100° C. or lower. Specific examples of volatile liquids include alcohols such as isopropyl alcohol (IPA), 1-propanol, ethanol, methanol, and 1-butanol; carboxylic acid esters such as butyl formate, ethyl acetate, and butyl acetate; aromatics such as toluene and benzene; and ethers such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate. Of these, IPA, which is used as a developer or cleaning liquid, is preferred.

[0019] The volatile liquid preferably contains substantially no water, in order to facilitate the formation of an aerosol flow. The water content in the volatile liquid is preferably 1000 ppm by mass or less, and more preferably 100 ppm by mass.

[0020] [Nanoparticles] The non-volatile impurities constituting the aerosol flow are, for example, nanoparticles. Hereinafter, a case where the non-volatile impurities constituting the aerosol flow are nanoparticles will be described.

[0021] In this specification, nanoparticles refer to particles having a particle diameter of 100 nm or less. The particle diameter of nanoparticles is preferably 60 nm or less, and more preferably 30 nm or less. The particle diameter of nanoparticles is usually 1.0 nm or more, preferably 2.0 nm or more, and more preferably 2.5 nm or more.

[0022] The particle diameter of nanoparticles is the diameter equivalent to the electrical mobility. Here, the electrical mobility of microspherical particles is inversely proportional to approximately the square of the particle diameter. Specifically, the particle diameter can be measured using the aforementioned DMA and CPC.

[0023] The particle shape of the nanoparticles may be a regular shape such as a rectangle, a plate, or a sphere, or may be an irregular shape that does not have a fixed shape but is a mixture of various shapes.

[0024] The nanoparticles are suspended when a mist flow is formed by spraying a volatile liquid and then the volatile liquid contained in the mist flow is vaporized to form an aerosol flow. The nanoparticles include nanoparticles contained in the volatile liquid, condensates of nanoparticles, and even nanoparticles that do not exist as particles in the volatile liquid as long as they are suspended when the aerosol flow is formed.

[0025] The nanoparticles must be non-volatile when vaporizing the volatile liquid contained in the mist stream, and the temperature at which the volatile liquid contained in the mist stream is vaporized is generally 50° C. or higher and 400° C. or lower, as described below.

[0026] The nanoparticles may be inorganic particles, organic particles, or organic-inorganic composite particles. Examples of materials constituting the inorganic particles include metals, metal oxides, metal chlorides, metal nitrates, and metal complexes. Examples of metals include Al, Ca, Cd, Cr, Cu, Fe, Mg, Na, Ni, Zn, Au, Pt, and Ag. Among these, Cr, Cu, Fe, and Ni are preferred.

[0027] Examples of materials constituting the organic particles include phthalate esters such as hexadecane and dioctyl phthalate, high-boiling organic compounds such as hexanol and octanol, and polymer compounds such as vinylidene fluoride, polypropylene, polyethylene, ethylene propylene rubber (EPDM), fluororubber (FKM), and perfluoroelastomer (FFKM). For example, a polymer compound with a molecular weight of 4,000 corresponds to nanoparticles with a particle diameter of 2.5 nm to 3 nm, and a polymer compound with a molecular weight of 180,000 corresponds to nanoparticles with a particle diameter of approximately 10 nm.

[0028] [Nebulizer] Examples of the spraying method of the spraying part include an air spraying method, an ultrasonic spraying method, and an impactor method. Among these, the air spraying method is preferred. The spraying device equipped with the spraying part is not particularly limited, but examples thereof include a nebulizer.

[0029] The volume-based median diameter (D ５０The volume-based median diameter (D) of the droplets constituting the mist flow is preferably 0.5 μm or more and 50 μm or less, more preferably 1 μm or more and 20 μm or less, and even more preferably 2 μm or more and 5 μm or less. ５０ ) D on a volume basis ９０ The ratio (D ９０ / D ５０ ) is preferably 4 or less, more preferably 3 or less. ９０ / D ５０ When the value is 4 or less, stable measurement results are likely to be obtained when measuring the particle properties of non-volatile impurities contained in an aerosol flow.

[0030] D ５０ When the diameter of the nanoparticles is 50 μm or less, the time required for vaporizing the volatile liquid contained in the mist flow can be shortened. As a result, it is possible to shorten the heated region of the tube, which will be described later, and therefore the collision of the nanoparticles with the inner wall surface of the tube can be suppressed, and as a result, the loss of the nanoparticles can be suppressed. ５０ When the particle diameter is 0.5 μm or more, a mist flow is formed stably, and therefore the detection sensitivity of the DMA and CPC is fully exhibited when measuring the particle properties of non-volatile impurities contained in the aerosol flow.

[0031] D ５０ and D ９０ is measured by a laser diffraction method. An example of a measuring device is Spraytec (manufactured by Malvern Instruments).

[0032] The nebulizer further includes, for example, a storage tank. The material used for the areas of the injection part and the storage tank that come into contact with the volatile liquid is not particularly limited, but from the viewpoint of suppressing contamination by the volatile liquid and adsorption of non-volatile impurities, inorganic glass such as quartz glass and borosilicate glass, alloys such as stainless steel (SUS) and Hastelloy, fluororesins such as perfluoroalkoxyalkane (PFA) and polytetrafluoroethylene (PTFE), and resins such as PEEK are preferred, and from the viewpoint of cleanliness and stability, quartz glass, SUS, Hastelloy, and polyether ether ketone (PEEK) are more preferred. Examples of commercially available nebulizers include PFA Microflow Nebulizer G3285-80000 (manufactured by Agilent) for high-frequency inductively coupled plasma (ICP) optical emission spectrometry, PFA-ST Nebulizer (manufactured by ESI) (a combination of nebulizer ES-2044 and nebulizer tube ES-2040), and A79-SilQ Quartz Nebulizer (Type A or C) (manufactured by MEINHARD).

[0033] When fixing a nebulizer, an end cap used to fix an ICP spray chamber is generally used. Commercially available end caps include the spray chamber end cap G3280-60008 (manufactured by Agilent).

[0034] The volatile liquid may be supplied to the nebulizer either in-line or off-line.

[0035] When spraying the volatile liquid, atomizing gas (nebulizer gas) is sprayed from an atomizing gas pipe surrounding the spray part 2. At this time, the flow rate of the atomizing gas is preferably 0.5 L / min or more and 10 L / min or less, and more preferably 1.0 L / min or more and 5.0 L / min or less.

[0036] The temperature of the volatile liquid sprayed from the spray part is preferably 100° C. or less, and more preferably 20° C. or more and 50° C. or less. When the temperature of the volatile liquid sprayed from the spray part is 100° C. or less, distortion of the shape of the spray part is less likely to occur.

[0037] The atomizing gas is not particularly limited as long as it does not adversely affect the measurement of the particle properties of nanoparticles described below, and examples thereof include inert gases. The dew point of the atomizing gas is preferably −40° C. or lower. Examples of inert gases include nitrogen, air, and argon. In particular, when using DMA to measure the particle properties of nanoparticles, it is preferable to use nitrogen or air as the inert gas. Note that the inert gas is preferably supplied after passing through a HEPA filter to remove coarse particles.

[0038] The spray rate of the volatile liquid is preferably 0.01 mL / min to 10 mL / min, more preferably 0.1 mL / min to 1 mL / min. In order to set the volume-based median diameter of the droplets constituting the mist stream to 0.5 μm to 50 μm, the volume ratio of the volatile liquid to the atomizing gas is preferably 1,000 to 50,000, more preferably 5,000 to 20,000. The spray rate of the volatile liquid is preferably such that the vapor pressure when the entire amount of the volatile liquid is evaporated is equal to or less than the saturated vapor pressure at room temperature (e.g., 25°C), more preferably equal to or less than half of the saturated vapor pressure.

[0039] The method of supplying the volatile liquid to the spray unit may be a self-suction method that uses negative pressure generated by spraying the volatile liquid to suck the liquid, or a liquid delivery method that uses a pump to deliver the liquid. The self-suction method has the advantage of reducing the risk of contamination by the volatile liquid, while the liquid delivery method has the advantage of ensuring stable delivery. Examples of pumps that can be used include a diaphragm pump, a tube pump, a smooth flow pump, a plunger pump, and a syringe pump.

[0040] [Aerosol flow generating device] The aerosol flow generating device is used to generate an aerosol flow from a volatile liquid containing non-volatile impurities. The aerosol is used, for example, to measure the particle properties of nanoparticles contained in the aerosol flow. An example of an aerosol flow generating device will be described below with reference to FIG. 1.

[0041] The pipe 1 is continuous from the upstream end to the downstream end, and its central axis is horizontal, but a slight inclination (usually within 10°) of the central axis relative to the horizontal is permitted. The pipe 1 is straight, but a slight bend (usually within 10°) is permitted. The pipe 1 is a circular pipe. The upstream end of the pipe 1 is open, but may be closed to prevent outside air from entering.

[0042] A nebulizer spray unit 2 is installed on or near the central axis of the tubular body 1, and a volatile liquid is sprayed from the spray unit 2 to form a mist flow 3. As a result, the mist flow 3 flows inside the tubular body 1 from the upstream side to the downstream side.

[0043] A predetermined region 4 in the central axis direction of the tubular body 1 is heated by a heating unit 14. Therefore, the volatile liquid contained in the mist flow 3 is heated and vaporized, and an aerosol flow 5 containing nanoparticles derived from non-volatile impurities is formed. The aerosol flow 5 is then discharged from a cooling unit 6 to a sample supply unit 7 connected to a sample introduction unit of a particle property measuring device described below.

[0044] In the tubular body 1, the mist flow forming region 8 is the region between the downstream end of the ejector 2, i.e., the position where the volatile liquid is ejected from the ejector 2, and the upstream end of the predetermined region 4. The inner wall surface of substantially the entire mist flow forming region 8 has an inverted tapered shape 10, with the diameter increasing toward the downstream side. This makes it difficult for the mist flow 3 to collide with the inner wall surface of the tubular body 1, thereby suppressing the loss of non-volatile impurities. As a result, it becomes possible to precisely and stably measure the particle properties of non-volatile impurities.

[0045] In contrast, conventionally used pipes have a straight circular pipe with a substantially uniform diameter in the mist flow region 8. Specifically, the diameter of the circular pipe has been appropriately selected from approximately 5 mm to 50 mm, or approximately 20 mm to 40 mm. However, when a straight circular pipe is used, the edges of the mist flow 3 collide with the inner wall surface of the pipe in the half region from the downstream end of the mist flow expansion region 9, where the mist flow 3 expands as it flows. This causes a loss of non-volatile impurities, making it difficult to accurately measure the particle properties of the non-volatile impurities.

[0046] It is also possible to increase the diameter of the conventionally used tube in order to suppress the collision of the mist flow 3 with the inner wall surface of the tube. However, this would result in the formation of an excess space between the edge of the mist flow 3 and the inner wall surface of the tube. This would increase the number of droplets that disperse from the edge of the mist flow 3 into the excess space. These dispersed droplets would not flow at a speed that would accompany the mist flow 3, and would instead wander around and stagnate upstream of the nebulizer's injection port 2. This would result in the loss of nonvolatile impurities, making it difficult to accurately measure the particle properties of the nonvolatile impurities.

[0047] Here, the length of the mist flow forming region 8 is preferably 30 mm to 200 mm, and more preferably 80 mm to 150 mm. If the length of the mist flow forming region 8 is 200 mm or less, the mist flow 3 is less likely to collide with the inner wall surface of the tubular body 1. On the other hand, if the length of the mist flow forming region 8 is 30 mm or more, it is easier to ensure the mist flow expansion region 9.

[0048] The expansion angle (reverse taper angle) of the reverse taper shape 10 is preferably within a range of ±20° with respect to the expansion angle of the mist flow 3, and more preferably within a range of ±10°. When the expansion angle of the reverse taper shape 10 is within a range of ±20° with respect to the expansion angle of the mist flow 3, collision of the mist flow 3 with the inner wall surface of the tubular body 1 is suppressed. Note that the expansion angle of the reverse taper shape 10 is the angle of the inner wall surface of the region of the tubular body 1 having the reverse taper shape 10 with respect to the central axis direction of the tubular body 1 when viewed in cross section of the tubular body 1 (see FIG. 1 ).

[0049] The spread angle of the mist flow 3 is preferably 45° or less, and more preferably 30° or less. When the spread angle of the mist flow 3 is 45° or less, dispersion from the edges of the mist flow 3 to the vicinity of the inner wall surface of the tubular body 1 is suppressed. The spread angle of the mist flow 3 is preferably 10° or more. When the spread angle of the mist flow 3 is 10° or more, the mist flow 3 is formed with appropriate properties.

[0050] A method for measuring the spreading angle of the mist flow 3 will be described with reference to FIG.

[0051] (1) A volatile liquid is sprayed from the spray part 2 of the nebulizer, and the mist flow 3 is photographed from the side at a magnification of 1000 times using a high-speed camera as it spreads and flows.

[0052] (2) On the captured image, a straight line A is drawn from the center of the nebulizer's injection part 2 in the injection direction, and then a perpendicular line B is drawn downward from a position on the straight line A that is 1 mm away from the injection part 2.

[0053] (3) Observe the droplets present below the line A and upstream of the perpendicular line B, and extract droplets with a diameter of 10 μm or more (white-out droplets). If multiple droplets partially overlap, extract each of them. Then, draw a diagonal line C connecting an arbitrary point on the perpendicular line B to the downstream end of the lower inner wall surface of the ejection part 2, and count the number of white-out droplets that fall within the area surrounded by the diagonal line C, the perpendicular line B, and the line A. In this case, white-out droplets that overlap the diagonal line and the perpendicular line B or the line A are not counted.

[0054] (4) The position of an arbitrary point on the perpendicular line B where the oblique line C is drawn is moved up and down, and the number of white droplets that fit within the area surrounded by the oblique line C, the perpendicular line B, and the straight line A is counted, and the bottom line of the oblique line C that does not exceed 90% of the total number of white droplets extracted in (3) is determined. The angle between the bottom line of the oblique line C and the straight line A is measured and used as the spread angle of the mist flow 3.

[0055] The ratio of the expansion width of the diameter of the reverse tapered shape 10, i.e., the ratio of the maximum diameter to the minimum diameter, is preferably 1.2 to 5.0, and more preferably 1.5 to 3.0. The ratio of the expansion width of the reverse tapered shape 10 to the expansion width of the mist flow 3 in the mist flow expansion region 9 is preferably 1.5 to 10, and more preferably 2.0 to 4.0. The maximum diameter of the reverse tapered shape 10 is preferably 10 mm to 100 mm, and more preferably 30 mm to 70 mm.

[0056] The inner wall surface of almost the entire mist flow forming region 8 has an inverse tapered shape 10, but the frequency of collision of the mist flow 3 with the inner wall surface of the tubular body 1 becomes significant after the mist flow 3 has expanded. Therefore, it is sufficient that the inner wall surface of at least half of the region from the downstream end of the mist flow expansion region 9 in the mist flow forming region 8 has the inverse tapered shape 10. Preferably, it is sufficient that the inner wall surface of at least three-quarters of the region from the downstream end of the mist flow expansion region 9 in the mist flow forming region 8 have the inverse tapered shape 10.

[0057] When the inner wall surface of substantially the entire mist flow forming region 8 has the reverse tapered shape 10, the inner wall surface upstream of the downstream end of the injection portion 2 of the tubular body 1 may also have the reverse tapered shape 10. Furthermore, the inner wall surface of the tubular body 1 may have the reverse tapered shape 10 intermittently as long as the effect of the present invention is not impaired.

[0058] In the tubular body 1, the mist flow 3 that has passed through the mist flow forming region 8 is heated by the heating unit 14, and the volatile liquid is vaporized to form the aerosol flow 5. The length of the predetermined region 4 is preferably 50 mm or more and 500 mm or less, and more preferably 150 mm or more and 300 mm or less.

[0059] The heating unit 14 is not particularly limited as long as it can vaporize the volatile liquid contained in the mist flow 3 to form the aerosol flow 5, and examples thereof include a ribbon heater, a heat medium heater, and a tubular furnace. Among these, a tubular furnace is preferred.

[0060] The temperature of the predetermined region 4 is preferably equal to or higher than the boiling point of the volatile liquid, more preferably equal to or higher than the boiling point of the volatile liquid by 50° C. or more, and even more preferably equal to or higher than the boiling point of the volatile liquid by 100° C. or more. When the volatile liquid is isopropyl alcohol, the temperature of the predetermined region 4 is preferably equal to or higher than 82° C., more preferably equal to or higher than 132° C., and even more preferably equal to or higher than 182° C.

[0061] On the other hand, the temperature of the predetermined region 4 is preferably 400° C. or less, more preferably 300° C. or less, and even more preferably 250° C. or less. When the temperature of the predetermined region 4 is 400° C. or less, loss due to thermal decomposition of nonvolatile impurities is suppressed.

[0062] The diameter of a region 11 of the predetermined region 4 that is more than halfway from the upstream end is substantially the same as the diameter of the downstream end of the mist flow forming region 8. This prevents droplets of the volatile liquid from colliding with the inner wall surface of the tubular body 1 before they have fully evaporated. In this case, the length of the region 11 that is more than halfway from the upstream end is shorter than the length of the predetermined region 4.

[0063] Here, the diameter of the region 11 of the specified region 4, which is more than halfway from the upstream end, is preferably within a range of ±10% of the diameter of the downstream end of the mist flow forming region 8, and more preferably within a range of ±5%.

[0064] The length of the region 11 that is more than halfway from the upstream end may be approximately the same as the length of the predetermined region 4, as shown in FIGS. 2A, 2B, 2C, and 2D.

[0065] In order to supply the aerosol flow 5 to a sample introduction section of a particle property measurement device (described later), the diameter of the tubular body 1 must be reduced between a region 11 extending more than halfway from the upstream end and the sample supply section 7. Therefore, the inner wall surface of a reduced diameter region 12 between the downstream end of the predetermined region 4 and the downstream end of the region 11 extending more than halfway from the upstream end has a tapered shape 13 in which the diameter decreases toward the downstream side. This suppresses the loss of non-volatile impurities. This is because, when the inner wall surface of the tubular body 1 is heated, convection occurs from the inner wall surface of the tubular body 1 toward the central axis, making it difficult for the edges of the aerosol flow 5 to collide with the inner wall surface of the tubular body 1. In this case, the diameter of the cooling section 6 downstream of the predetermined region 4 is approximately the same.

[0066] Even when the length of region 11, which is more than halfway from the upstream end, is substantially the same as the length of predetermined region 4, it is preferable that the inner wall surface of the predetermined region downstream from the downstream end of predetermined region 4, i.e., the region where the temperature of cooling section 6 is high, have a tapered shape 13, as shown in Fig. 2C. In this case, the difference in temperature between the high-temperature region of cooling section 6 and predetermined region 4 is preferably 50°C or less, and more preferably 20°C or less. Furthermore, as shown in Fig. 2D, the inner wall surface of substantially the entire region downstream from the downstream end of predetermined region 4, i.e., substantially the entire region of cooling section 6, may have a tapered shape 13.

[0067] The aerosol flow 5 is cooled in the cooling unit 6, typically to a temperature of 10°C to 40°C, and discharged from the sample supply unit 7 connected to the sample introduction unit of the particle property measurement device. In this case, if the amount of volatile liquid sprayed from the nebulizer spray unit 2 is large and some of the vaporized volatile liquid liquefies, an exhaust unit may be provided in the cooling unit 6 to discharge the volatile liquid outside the system. Furthermore, if some of the vaporized volatile liquid liquefies, a gas replacement device may be used to replace some of the vaporized volatile liquid with an inert gas such as nitrogen or air, as long as this does not significantly affect the particle property measurement of the nanoparticles. Examples of commercially available gas replacement devices include GED (manufactured by Rhozeas) and APEXΩ (manufactured by ESI).

[0068] The diameter contraction angle (taper angle) of the tapered shape 13 is preferably 10° or more and 45° or less, and more preferably 15° or more and 30° or less. When the diameter contraction angle of the tapered shape 13 is 10° or more and 45° or less, the collision of the aerosol flow 5 with the inner wall surface of the tubular body 1 is mitigated. The diameter contraction angle of the tapered shape 13 is the angle of the inner wall surface of the region of the tubular body 1 having the tapered shape 13 with respect to the central axis direction of the tubular body 1 when viewed in cross section of the tubular body 1 (see FIG. 1 ). The length of the diameter contraction region 12 is preferably 20 mm or more and 125 mm or less, and more preferably 40 mm or more and 80 mm or less. The diameter contraction angle of the tapered shape 13 in FIG. 2D may be less than 10°. In this case, the difference between the diameter of the final outlet of the cooling section 6 and the diameter of the sample introduction section of the particle property measurement device is preferably within a range of ±1 mm. The diameter of the cooling part 6 is preferably 3 mm or more and 20 mm or less, and more preferably 5 mm or more and 8 mm or less.

[0069] The tube body 1 preferably contains a conductive material. This suppresses the adsorption of nanoparticles to the inner wall surface of the tube body 1 due to electrostatic attraction. Examples of conductive materials include stainless steel (SUS), Hastelloy, iron, and conductive resin. Among these, stainless steel or Hastelloy is particularly preferred. In this case, it is preferable to ground the tube body 1 from the viewpoint of reducing the influence of static electricity.

[0070] Furthermore, the tubular body 1 preferably includes a non-conductive material that is more likely to be positively charged than aluminum in the triboelectric series. Here, the triboelectric series refers to the tendency of two materials to be positively or negatively charged due to friction between them. Furthermore, because air tends to be positively charged, the amount of static electricity generated by friction with air is less for materials that tend to be positively charged than for materials that tend to be negatively charged. Therefore, materials that tend to be positively charged are less likely to be charged in air than materials that tend to be negatively charged. On the other hand, aluminum is positioned in the middle of the triboelectric series between materials that tend to be positively charged and materials that tend to be negatively charged. Therefore, materials that are more likely to be positively charged than aluminum are less likely to be charged with static electricity in air. Examples of non-conductive materials that are more likely to be positively charged than aluminum include soda glass, quartz glass, nylon, and acrylic resin. Of these, quartz glass is particularly preferred.

[0071] As described above, the volatile liquid is atomized by the atomizing gas and injected into the inside of the tubular body 1 from the injection part 2 of the nebulizer, but from the viewpoint of smooth flow and ease of introducing a sample into the particle property measuring device, an additional gas may be supplied as appropriate from a desired location when the mist flow 3 and the aerosol flow 5 flow inside the tubular body 1. In this case, the volume ratio of the total amount of the additional gas and the atomizing gas to the aerosol flow 5 introduced into the sample introduction part of the particle property measuring device is preferably 0.9 or more and 2.0 or less, more preferably 1.0 or more and 1.5 or less.

[0072] The additional gas is not particularly limited, but may be the same inert gas as the atomizing gas, and preferably the same inert gas as the atomizing gas. Note that, like the atomizing gas, the additional gas is preferably passed through a HEPA filter to remove coarse particles before being supplied.

[0073] The location where the additional gas is supplied is not particularly limited, but is preferably near the injection part 2 in order to increase the flow rate of the gas inside the tubular body 1. The distance between the location where the additional gas is supplied and the injection part 2 is preferably 1 mm or more and 100 mm or less, and more preferably 5 mm or more and 50 mm or less. In this case, the additional gas may be supplied from the upstream side of the injection part 2.

[0074] [Particle Property Measuring Apparatus and Particle Property Measuring Method] Next, a method for measuring the particle properties of nanoparticles contained in the aerosol flow 5 formed by the aerosol flow forming apparatus shown in Fig. 1 will be described. The particle properties are not particularly limited, but examples thereof include the number of particles, the average particle size, the particle size distribution, and the particle composition.

[0075] When measuring the particle number, a CPC, a Faraday cup ammeter, or an air particle counter may be used. When measuring the average particle diameter, a DMA and a CPC may be combined to measure the electrical mobility equivalent diameter. When measuring the particle size distribution, a DMA and a CPC may be combined, or a DMA and a Faraday cup ammeter may be combined. When measuring the particle composition, a single particle inductively coupled plasma mass spectrometer (SP / ICP / MS) may be used. Among these, measurement of the particle number using a CPC or measurement of the particle size distribution using a combination of a DMA and a CPC is preferred.

[0076] Instead of supplying the aerosol flow 5 from the sample supply unit 7 to the sample introduction unit of the particle property measurement device, the nanoparticles may be collected from the aerosol flow 5 and then the particle properties of the nanoparticles may be measured. Examples of methods for collecting nanoparticles include collecting nanoparticles with a filter, collecting nanoparticles by adhering them to a flat surface, and collecting nanoparticles by dissolving or dispersing the aerosol flow 5 in a liquid. Examples of collecting devices include a spot sampler (manufactured by Aerosol Device) and a nanoparticle sampler (manufactured by TSI).

[0077] Next, as an example of a method for measuring particle properties using a particle property measuring device, a method for measuring particle size distribution using a scanning mobility particle size analyzer (SMPS) 19 (see FIG. 3 ) in which a DMA 15 and a CPC 16 are combined will be described.

[0078] The aerosol flow 5 discharged from the cooling section 6 of the tube 1 is supplied to the sample introduction section of the DMA 15 via the sample supply section 7 and the sample supply section 18. The DMA 15 utilizes the difference in the migration speed of charged particles in an electric field to classify nanoparticles depending on the applied voltage and the flow rate of the fluid in which the particles are dispersed. When the aerosol flow 5 is supplied to the sample introduction section of the DMA 15, the aerosol flow 5 passes through a neutralizer 20 to achieve a balanced charge state. This improves the accuracy of measuring the particle size distribution. The neutralizer 20 is not particularly limited, but examples include a neutralizer using americium (241Am) as a radiation source and a soft X-ray neutralizer. Examples of commercially available neutralizers include the Am241 neutralizer (manufactured by Tokyo Dylec), and examples of commercially available soft X-ray neutralizers include the 3088 (manufactured by TSI).

[0079] The particle diameter classified by DMA15 is preferably 1 nm or more, more preferably 2 nm or more, and even more preferably 2.5 nm or more. When the particle diameter classified by DMA15 is 1.0 nm or more, the measurement accuracy of the particle diameter distribution is high. On the other hand, the particle diameter classified by DMA15 is preferably 100 nm or less, more preferably 60 nm or less, and even more preferably 30 nm or less. When the particle diameter classified by DMA15 is 100 nm or less, the measurement accuracy of the particle diameter distribution is high. By using two or more types of DMA15 with different lengths in combination, particles with a particle diameter of 1 nm or more and 1000 nm or less can also be classified. Commercially available DMA15 products include, for example, 3080 / 3085A (manufactured by TSI) and 3082 / 3086 (manufactured by TSI).

[0080] The ratio of the flow rate of the sheath flow gas to the amount of aerosol introduced into the DMA 15 is preferably 2 or more and 50 or less. In this case, the amount of aerosol introduced into the DMA 15 is preferably 0.5 L / min or more and 100 L / min or less, and more preferably 1 L / min or more and 5 L / min or less.

[0081] The aerosol classified by the DMA 15 is supplied to the sample introduction port of the CPC 16 via the sample supply port 17, but the discharge port of the DMA 15 and the sample introduction port of the CPC 16 may also be directly connected to supply the aerosol to the CPC 16. The CPC 16 measures the number concentration of nanoparticles by condensing supersaturated vapor onto nanoparticles, causing them to condense and grow into droplets that can be optically detected. The condensed droplets are typically counted by light scattering. When the droplets pass through a detection area irradiated with focused light, they emit scattered light, and a portion of the scattered light is detected by a photodetector. The number concentration of nanoparticles is measured from the frequency of scattered light detection and the volumetric flow rate of the nanoparticles.

[0082] The solvent for condensing and growing nanoparticles is not particularly limited, but examples include isopropyl alcohol, butanol, water, and diethylene glycol. Among these, 1-butanol, water, and diethylene glycol are more preferable. If droplets of a measurable size cannot be obtained with one solvent, another CPC 16 may be subsequently connected to obtain droplets of a measurable size, and the number concentration of nanoparticles may then be measured.

[0083] CPC16 is preferably capable of condensation growth of particles with a particle diameter of 10 nm or less, more preferably capable of condensation growth of particles with a particle diameter of 2 nm or less, and even more preferably capable of condensation growth of particles with a particle diameter of 1 nm or less. The amount of classified aerosol introduced is preferably 0.1 L / min or more, and more preferably 1 L / min or more. A classified aerosol introduced at a rate of 0.1 L / min or more can supply a large amount of nanoparticles. Note that the amount of classified aerosol introduced refers to the amount actually introduced into CPC16 to condense and grow nanoparticles, excluding gas passed through the filter by bypass and exhaust gas. Since too much introduced amount of classified aerosol increases the size of the device, it is preferable that the amount introduced be 10 L / min or less. Commercially available CPC16 products include 3789 (TSI) (condensate: water), 3776 (TSI) (condensate: butanol), and 3757 / 3750 (TSI) (condensate: ethylene glycol / butanol).

[0084] The sample supply unit 18 and the sample supply unit 17 in the SMPS 19 preferably include a non-electrostatic material, similar to the tubular body 1. Examples of non-electrostatic materials include conductive fluororesin (e.g., PFA, PTFE), conductive silicone resin, stainless steel (SUS), conductive materials such as metals, and quartz glass. Among these, quartz glass and SUS are particularly preferred from the viewpoint of heat resistance.

[0085] The sample supply unit 18 and the sample supply unit 17 can contain a conductive silicone resin or a conductive fluororesin because the temperature of the aerosol flow that flows through them is low (usually 50° C. or less). If a flexible resin is used, the sample supply unit 18 and the sample supply unit 17 can be bent to facilitate connection to the device.

[0086] The length of the sample supply part 17 is preferably 300 mm or less, and more preferably 150 mm or less. When the length of the sample supply part 17 is 300 mm or less, adsorption of nanoparticles to the inner surface of the sample supply part 17 is suppressed.

[0087] In the SMPS 19, if the DMA 15 is omitted and the aerosol is directly supplied to the sample introduction part of the CPC 16, the total number of nanoparticles can be measured.

[0088] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-described embodiments may be modified as appropriate within the scope of the spirit of the present invention.

[0089] Examples of the present invention will be described below, but the present invention is not limited to these examples. In these examples and comparative examples, the spread angle of the mist stream 3 sprayed from the spray portion 2 of the nebulizer was measured as follows.

[0090] [Spread Angle of Mist Stream] Volatile liquid was sprayed horizontally from the spray unit 2 of the nebulizer at a spray rate of 0.1 mL / min, and the flowing mist stream 3 was photographed from the side using a high-speed camera (manufactured by Photron) at a magnification of 1000. The spread angle of the mist stream was measured using the photographed image by the method shown in Figure 4.

[0091] That is, a straight line A was drawn horizontally from the center of the ejection part 2 of the nebulizer on the photographed image, and then a perpendicular line B was drawn downward from a position on the straight line A that was 1 mm away from the ejection part 2.

[0092] Next, droplets present below line A and upstream of line B were observed, and droplets with a diameter of 10 μm or more (white-out droplets) were extracted. Then, a diagonal line C was drawn connecting an arbitrary point on line B to the downstream end of the lower inner wall surface of the spray portion 2, and the number of white-out droplets falling within the area surrounded by line C, line B, and line A was counted. The position of the arbitrary point on line B where line C was drawn was then moved up and down, and the number of white-out droplets falling within the area surrounded by line C, line B, and line A was counted, and the bottom line of line C, which did not exceed 90% of the total number of white-out droplets extracted, was determined. The angle between the bottom line of line C and line A was measured and used as the spread angle of the mist flow 3.

[0093] Example 1 Using the aerosol flow forming device shown in FIG. 1, an aerosol flow was formed from IPA XE (manufactured by Tokuyama) as a volatile liquid.

[0094] Here, a volatile liquid at 20 ° C. filled in a high-grade PFA bottle (500 ml) serving as a storage tank is supplied to the nebulizer's injection part 2 via a PFA tube. A PFA microflow nebulizer G3285-80000 (manufactured by Agilent) for high-frequency inductively coupled plasma (ICP) optical emission spectroscopy was used as the nebulizer. The volatile liquid was injected from injection part 2 at a flow rate of 0.1 mL / min using a self-suction method, and nitrogen was injected as the atomization gas at a flow rate of 1 L / min from the atomization gas tube surrounding injection part 2. Nitrogen purified by passing through a HEPA filter (manufactured by TSI) was used.

[0095] The droplets constituting the mist flow 3 have a volume-based median diameter (D ５０ ) is 4.6 μm, and the volume-based D ９０ is 11 μm, and D ９０ / D ５０ Furthermore, the length of the mist flow expansion region 9 was 40 mm, and the maximum expansion width at the most downstream side was 15 mm.

[0096] On the other hand, the tube 1 was a circular tube made of quartz and was placed horizontally. The characteristics of the circular tube are described below.

[0097] Total length: 670 mm Diameter of upstream end: 30 mm Length of mist flow forming region 8: 100 mm Spread angle of mist flow 3: 14° Diameter expansion angle of inverse taper shape 10: 6° Diameter of downstream end of inverse taper shape 10: 50 mm Ratio of diameter expansion width of inverse taper shape 10 (ratio of maximum diameter (50 mm) to minimum diameter (30 mm)): 1.7 Ratio of expansion width of mist flow 3 (maximum expansion width 15 mm at the most downstream of mist flow expansion region 9) of inverse taper shape 10 (50 mm): 3.3 Length of predetermined region 4: 250 mm Length of diameter contraction region 12: 70 mm Diameter contraction angle of tapered shape 13: 17° Length of cooling section 6: 300 mm Diameter of cooling section 6: 6 mm

[0098] In the tubular body 1, the predetermined region 4 is heated by being surrounded by a tubular furnace serving as the heating unit 14. Air that had passed through a HEPA filter (manufactured by TSI) was drawn in from position X of the cooling unit 6 at a rate of 0.1 L / min and introduced into the DMA 15 together with the aerosol.

[0099] The temperature of the predetermined region 4 was set to 200° C. The temperature of the aerosol discharged from the cooling section 6 was 30° C.

[0100] The aerosol was introduced into the SMPS 19 shown in Figure 3, and the particle size distribution of the nanoparticles was measured. Here, 3082 / 3086 (manufactured by TSI) was used as the DMA 15, and CPC3757 / 3750 (manufactured by TSI) was used as the CPC 16. Furthermore, Am241 (manufactured by Tokyo Dylec) was used as the neutralizer 20.

[0101] Furthermore, a quartz glass tube having a length of 10 cm was used as the sample supply section 7, a conductive silicone resin tube having a length of 20 cm was used as the sample supply section 18, and a conductive silicone resin tube was used as the sample supply section 17.

[0102] During the analysis, the amount of aerosol introduced into the DMA15 was set to 2.5 L / min, and the flow rate of the sheath flow gas was set to 25 L / min. The nanoparticle classification range was set to 1.02 to 28.9 nm, and the time required for one analysis to classify into this classification range was set to 300 seconds.

[0103] On the other hand, the amount of aerosol introduced into the CPC 16 was also set to 2.5 L / min. Hereinafter, the unit of the number of detected particles in the CPC is described as particles / cc, which is the number of detected particles per unit amount of gas introduced into the CPC.

[0104] The particle size distribution of the nanoparticles was measured under the above conditions. Before measuring the particle size distribution of the nanoparticles, only nitrogen was flowed as the atomizing gas at a flow rate of 1 L / min without injecting the volatile liquid from the injection part 2 for 1 hour, and then the particle count was measured three times under the same conditions, and the particle count was found to be 0 particles / cc. This confirmed that when only nitrogen was flowed, nanoparticles were not detected.

[0105] Subsequently, the particle size distribution of the nanoparticles was measured in the same manner as above, except that the volatile liquid was sprayed from the spray unit 2. As a result, the number of particles having a particle size of 1 to 30 nm was 13.3 × 10 ３ The number of particles of 30 to 60 nm was 10 / cc.

[0106] Next, the particle size distribution of the nanoparticles was measured in the same manner as above, except that a liquid in which gold particles with a mode particle size of 40 nm were dispersed in IPA XE (manufactured by Tokuyama) at a concentration of 50 ppb was sprayed from the spraying unit 2. The mode particle size was 44 nm, and the number of particles with particle sizes of 30 to 60 nm was 6.9 × 10 ３ Assuming that the measured particles were spherical, the mass of gold particles calculated from the particle diameter and particle number distribution of 30 to 60 nm was 93% of the amount introduced.

[0107] Example 2 The particle size distribution of nanoparticles was measured in the same manner as in Example 1, except that the tube shown in Fig. 2A was used instead of the tube 1. The tube shown in Fig. 2A was manufactured in the same manner as the tube 1, except that the diameter of the tube in the diameter-reducing region 12 was not changed.

[0108] As a result, after flowing only nitrogen at a flow rate of 1 L / min for 1 hour without spraying any volatile liquid from the spray part 2, the particle count was measured three times under the same conditions, and the particle count was found to be 0 particles / cc.

[0109] Subsequently, the particle size distribution of the nanoparticles was measured in the same manner as above, except that the volatile liquid was sprayed from the spray unit 2. As a result, the number of particles having a particle size of 1 to 30 nm was 7.6 × 10 ３ The number of particles of 30 to 60 nm was 5.8 / cc, which indicates that the number of particles is slightly reduced compared to Example 1.

[0110] Next, the particle size distribution of the nanoparticles was measured in the same manner as above, except that a solution in which gold particles with a mode particle size of 40 nm were dispersed in IPA XE (manufactured by Tokuyama) at a concentration of 50 ppb was sprayed from the spraying unit 2. The mode particle size was 44 nm, and the number of particles with particle sizes of 30 to 60 nm was 5.5 × 10 ３The particle density was 75% of the amount introduced, based on the particle diameter of 30 to 60 nm and the particle number distribution, assuming that the measured particles were spherical. This indicates that the particle number and the mass of the gold particles were slightly reduced compared to Example 1.

[0111] Example 3 The particle distribution of nanoparticles was measured in the same manner as in Example 1, except that a spray chamber end cap G3280-60008 (Agilent) was used to fix the nebulizer to the upstream end, and the measurement conditions were changed as follows: Features of the circular tube that differ from those in Example 1 are described below.

[0112] Length of mist flow forming region 8: 125 mm Length of diameter-reducing region 12: 40 mm Diameter-reducing angle of tapered shape 13: 29°

[0113] As a result, after flowing only nitrogen at a flow rate of 1 L / min for 1 hour without spraying any volatile liquid from the spray part 2, the particle count was measured three times under the same conditions, and the particle count was found to be 0 particles / cc.

[0114] Subsequently, the particle size distribution of the nanoparticles was measured in the same manner as above, except that the volatile liquid was sprayed from the spray unit 2. As a result, the number of particles having a particle size of 1 to 30 nm was 15.5 × 10 ３ The number of particles of 30 to 60 nm was 12 / cc.

[0115] Next, the particle size distribution of the nanoparticles was measured in the same manner as above, except that a liquid in which gold particles with a mode particle size of 40 nm were dispersed in IPA XE (manufactured by Tokuyama) at a concentration of 50 ppb was sprayed from the spraying unit 2. The mode particle size was 46 nm, and the number of particles with particle sizes of 30 to 60 nm was 7.1 × 10 ３ Assuming that the measured particles were spherical, the mass of gold particles calculated from the particle diameter and particle number distribution of 30 to 60 nm was 95% of the amount introduced.

[0116] Example 4 The particle distribution of nanoparticles was measured in the same manner as in Example 1, except that the tube shown in FIG. 2C was used instead of the tube 1, an A79-SilQ quartz nebulizer Type C (manufactured by MEINHARD) was used as the nebulizer, and a spray chamber end cap G3280-60008 (manufactured by Agilent) was used to secure the nebulizer to the upstream end. The measurement conditions were changed as follows: The temperature of the predetermined region 4 was set to 100°C, and a soft X-ray neutralizer 3088 (manufactured by TSI) was used as the neutralizer 20. A volatile liquid (IPA-XE) was sprayed from the spray unit 2 at a flow rate of 0.24 ml / min using a self-suction system. The droplet diameter of the mist stream 3, even when using this nebulizer, was equivalent to that of Example 1. The characteristics of the circular tube and mist stream that differ from those of Example 1 are described below.

[0117] Length of mist flow forming region 8: 125 mm Spread angle of mist flow 3: 15° Length of diameter-reducing region 12: 40 mm Diameter-reducing angle of tapered shape 13: 14° Length of cooling section 6: 250 mm

[0118] As a result, after flowing only nitrogen at a flow rate of 1 L / min for 1 hour without spraying any volatile liquid from the spray part 2, the particle count was measured three times under the same conditions, and the particle count was found to be 0 particles / cc.

[0119] Subsequently, the particle size distribution of the nanoparticles was measured in the same manner as above, except that the volatile liquid was sprayed from the spray unit 2. As a result, the number of particles having a particle size of 1 to 30 nm was 42.6 × 10 ３ The number of particles of 30 to 60 nm was 24 / cc.

[0120] Next, the particle size distribution of the nanoparticles was measured in the same manner as above, except that a liquid in which gold particles with a mode particle size of 40 nm were dispersed at a concentration of 50 ppb in IPA XE (manufactured by Tokuyama) was sprayed from the spraying unit 2. The mode particle size was 45 nm, and the number of particles with particle sizes of 30 to 60 nm was 18.1 × 10 ３ Assuming that the measured particles were spherical, the mass of gold particles calculated from the particle diameter and particle number distribution of 30 to 60 nm was 100% of the amount introduced.

[0121] Comparative Example 1 The particle size distribution of nanoparticles was measured in the same manner as in Example 1, except that a straight circular tube having a total length of 670 mm and an opening diameter of 30 mm was used instead of the tube body 1 .

[0122] As a result, after flowing only nitrogen at a flow rate of 1 L / min for 1 hour without spraying any volatile liquid from the spray part 2, the particle count was measured three times under the same conditions, and the particle count was found to be 0 particles / cc.

[0123] Subsequently, the particle size distribution of the nanoparticles was measured in the same manner as above, except that the volatile liquid was sprayed from the spray unit 2. As a result, the number of particles having a particle size of 1 to 30 nm was 1.5 × 10 ３ The number of particles of 30 to 60 nm was 2.1 / cc, which indicates that the number of particles is significantly reduced compared to Example 1.

[0124] Next, the particle size distribution of the nanoparticles was measured in the same manner as above, except that a solution in which gold particles with a mode particle size of 40 nm were dispersed in IPA XE (manufactured by Tokuyama) at a concentration of 50 ppb was sprayed from the spraying unit 2. The mode particle size was 44 nm, and the number of particles with particle sizes of 30 to 60 nm was 3.0 × 10 ３ The particle count was 1 / cc. Assuming that the measured particles were spherical, the particle diameter of 30 to 60 nm and the mass of the gold particles calculated from the particle number distribution were 40% of the amount introduced. This shows that the particle count and mass of the gold particles were significantly reduced compared to Example 1.

[0125] From the above, it can be seen that the loss of nanoparticles is small when the aerosol flow forming devices of Examples 1 to 4 (particularly Examples 1, 3, and 4) are used.

[0126] DESCRIPTION OF SYMBOLS 1; Tube 2; Injection section 3; Mist flow 4; Predetermined region 5; Aerosol flow 6; Cooling section 7; Sample supply section 8; Mist flow forming region 9; Mist flow expansion region 10; Inverse tapered shape 11; Region extending more than halfway from the upstream end 12; Diameter-reducing region 13; Tapered shape 14; Heating section 15; DMA 16; CPC 17; Sample supply section 18; Sample supply section 19; SMPS 20; Neutralizer

Claims

1. An apparatus for forming an aerosol flow from a volatile liquid containing non-volatile impurities, comprising: a tubular body; an injection unit installed on or near the central axis of the tubular body, which injects the volatile liquid and forms a mist flow; and a heating unit which heats a predetermined region in the central axis direction of the tubular body and vaporizes the volatile liquid contained in the mist flow to form an aerosol flow, wherein the tubular body has an inner wall surface in a region between the downstream end of the injection unit and the upstream end of the predetermined region, in a region of at least half the region from the downstream end of the region where the mist flow spreads as it flows, with a reverse tapered shape in which the diameter increases toward the downstream side, and the diameter of the predetermined region in a region of more than half the region from the upstream end is approximately constant.

2. The aerosol flow forming device according to claim 1, wherein the inner wall surface of the tubular body has a tapered shape in which the diameter decreases toward the downstream side from the downstream end of a region more than halfway from the upstream end to a predetermined region downstream.

3. The aerosol flow forming device according to claim 2, wherein the angle of contraction of the tapered shape is 10° or more and 45° or less.

4. An aerosol flow forming device according to any one of claims 1 to 3, wherein the amount of the volatile liquid sprayed is 0.01 mL / min or more and 10 mL / min or less, and the volume-based median diameter of the droplets constituting the mist flow is 0.5 μm or more and 50 μm or less.

5. An aerosol flow forming device according to any one of claims 1 to 3, wherein the angle of expansion of the inverse tapered shape is within a range of ±20° with respect to the angle of expansion of the mist flow.

6. The aerosol flow forming device according to claim 5, wherein the mist flow has a divergence angle of 45° or less.

7. An aerosol flow forming device according to any one of claims 1 to 3, wherein the ratio of the maximum diameter to the minimum diameter of the inverted tapered shape is 1.2 or more and 5 or less.

8. An aerosol flow forming device according to any one of claims 1 to 3, wherein the tube comprises a conductive material.

9. The aerosol flow forming device according to claim 8, wherein the conductive material is stainless steel or Hastelloy.

10. An aerosol flow forming device according to any one of claims 1 to 3, wherein the tube contains a non-conductive material that is more likely to be positively charged than aluminum in a triboelectric series.

11. The aerosol flow forming device according to claim 10, wherein the non-conductive material is quartz glass.

12. The aerosol flow forming device according to any one of claims 1 to 3, wherein the volatile liquid is isopropyl alcohol.

13. An aerosol flow generating device according to any one of claims 1 to 3, which is used to measure the particle properties of non-volatile impurities contained in the aerosol flow.

14. A particle property measuring device for measuring the particle properties of non-volatile impurities contained in a volatile liquid, comprising: an aerosol flow generating device according to any one of claims 1 to 3; and a sample introduction section for introducing the aerosol flow.

15. The particle property measuring device according to claim 14, further comprising a condensation particle counter, for measuring the number of particles of the non-volatile impurities.

16. The particle property measuring device according to claim 14, which is equipped with a scanning mobility particle size measuring device that combines a differential mobility classifier and a condensation particle counter, and measures the particle size distribution of the non-volatile impurities.

17. A method for measuring particle properties of nonvolatile impurities contained in a volatile liquid, comprising measuring the number of particles of the nonvolatile impurities using the particle property measuring device described in claim 15.

18. A method for measuring particle properties of non-volatile impurities contained in a volatile liquid, comprising measuring the particle size distribution of the non-volatile impurities using the particle property measuring device described in claim 16.

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