Flow particle measuring apparatus and flow particle measuring method

Abstract

Disclosed are a flow particle measuring apparatus and a flow particle measuring method. The flow particle measuring apparatus comprises: a light source for generating a laser beam; a flow cell through which a liquid sample including particles passes; a detector for detecting signals caused by plasma being generated when the laser beam collides with the particles; and an averaging unit for reducing deviations in the frequency and intensity of the plasma.

Description

Fluid particle measuring device and fluid particle measuring method

[0001] The present invention relates to a fluid particle measurement device and a fluid particle measurement method. More specifically, the present invention relates to a fluid particle measurement device and a fluid particle measurement method including a light source and a fluid cell.

[0002]

[0003] Chemicals such as etchants, rinse agents, and developers may be used in the manufacturing process of electronic devices such as display device semiconductor devices. As the critical dimensions of the electronic devices decrease, higher purity chemicals are used.

[0004] For example, if the chemical substance contains nanoscale impurity particles, it may reduce the yield and reliability of the electronic device manufacturing process. For example, particles with a particle size of 100 nm or less, 50 nm or less, or even 10 nm in size need to be detected and managed in high-purity chemicals used in electronic device processes.

[0005] In order to detect particles within the chemical substance as a continuous process unit, the particles can be detected while continuously passing the chemical substance through a flow cell. For example, a detection signal can be generated via a light source while the particles are supplied / passed through the flow cell.

[0006] However, the waveform and intensity of the detection light generated from the light source may vary depending on the region. In this case, variations may also occur in the frequency and intensity of the detection signal generated from the particles. For example, the intensity and frequency of the shock wave generated when the particle structure is excited by the detection light may become uneven, resulting in a decrease in detection reliability and resolution.

[0007] For example, Korean Patent Publication No. 10-1504061 discloses a sample measurement system using a laser light source.

[0008]

[0009] One object of the present invention is to provide a fluid particle measuring device having improved measurement precision and reliability.

[0010] One object of the present invention is to provide a method for measuring fluid particles with improved measurement precision and reliability.

[0011]

[0012] 1. A fluid particle measurement device comprising: a light source generating a laser beam; a flow cell through which a liquid sample containing particles passes; a detector detecting a signal caused by plasma generated when the laser beam collides with the particles; and an averaging unit reducing frequency and intensity deviations of the plasma.

[0013] 2. A fluid particle measuring device according to the above 1, wherein the averaging section includes a beam shaping section that flattens the peak area of ​​the laser beam incident on the fluid cell.

[0014] 3. A fluid particle measuring device, further comprising a lens disposed between the light source and the fluid cell in the above 2, wherein the beam forming unit is disposed between the fluid cell and the lens.

[0015] 4. A fluid particle measuring device, further comprising a lens disposed between the light source and the fluid cell in the above 3, wherein the beam forming unit is integrated with the lens.

[0016] 5. In the above 1, the averaging unit is a fluid particle measuring device included in the fluid cell.

[0017] 6. A fluid particle measuring device according to the above 5, wherein the averaging section includes a partition wall that defines a flow space of the liquid sample within the flow cell.

[0018] 7. A fluid particle measuring device according to 6 above, wherein the fluid space has a shape that reflects a change in the diameter of the laser beam incident on the fluid cell.

[0019] 8. A fluid particle measuring device according to 6 above, wherein the fluid space has a cross-section in the shape of a bow tie.

[0020] 9. A method for measuring flow particles, comprising: continuously supplying a liquid sample containing target particles to a flow cell; generating plasma from the target particles by irradiating a laser beam onto the flow cell; equalizing the frequency and intensity of the plasma; and detecting a detection signal induced from the plasma to derive information on the target particles.

[0021] 10. A method for measuring fluid particles, wherein in the above 9, the step of leveling the frequency and intensity of the plasma includes leveling the peak area of ​​the laser beam incident on the fluid cell.

[0022] 11. A method for measuring fluid particles, wherein in the above 10, flattening the peak area of ​​the incident laser beam includes converting a laser beam having a Gaussian distribution shape into a trapezoidal or rectangular laser beam.

[0023] 12. A method for measuring fluid particles, wherein in the above 9, the step of equalizing the frequency and intensity of the plasma includes limiting the flow space of the liquid sample within the flow cell according to a change in the diameter of the laser beam incident on the flow cell.

[0024]

[0025] A fluid particle measurement device according to embodiments of the present invention may include an averaging unit that uniformly adjusts the intensity of laser light incident from a laser source. The averaging unit may smooth out the laser intensity within a camera observation area within a fluid cell. Accordingly, the variation in plasma detection intensity across different areas within the camera observation area may be reduced, while improving particle measurement accuracy and reliability.

[0026] In some embodiments, the averaging unit may be included in a flow cell. The flow space in the flow cell may be fitted by the averaging unit according to the diameter / intensity of the laser light, thereby uniformizing the plasma intensity / frequency within the flow space.

[0027]

[0028] FIG. 1 is a schematic block diagram illustrating a fluid particle measurement device according to exemplary embodiments.

[0029] Figure 2 is a schematic drawing for explaining the form in which laser light is incident on a flow cell in a flow particle measuring device according to a comparative example.

[0030] Figures 3 and 4 are graphs for explaining the propagation profile of laser light in a fluid particle measuring device according to a comparative example.

[0031] FIG. 5 is a schematic drawing for explaining the form in which laser light is incident on a flow cell in a flow particle measuring device according to exemplary embodiments.

[0032] FIGS. 6 and 7 are graphs illustrating the propagation profile of laser light in a fluid particle measuring device according to exemplary embodiments.

[0033] FIG. 8 is a schematic cross-sectional view showing an averaging portion of a fluid particle measuring device according to some embodiments.

[0034]

[0035] Embodiments of the present invention provide a fluid particle measurement device including a fluid cell and a light source. In addition, a particle measurement method using the fluid particle measurement device is provided.

[0036] The above-described fluid particle measuring device may be a device that calculates the number and size of fluid particles by detecting a shock wave or flash caused by plasma generated when a laser beam collides with fluid particles. According to exemplary embodiments, the fluid particle measuring device can measure the size and frequency (number) of nanoscale particles of 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 50 nm or less, 40 nm or less, 30 nm or less, 20 nm or less, and 10 nm or less.

[0037] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. However, the following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the contents of the invention described above, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited to the matters described in such drawings.

[0038] The terms “first,” “second,” “top,” “bottom,” “upper,” and “lower” used in this specification do not limit absolute positions or orders, but are used in a relative sense to distinguish different components or parts.

[0039] FIG. 1 is a schematic block diagram illustrating a fluid particle measurement device according to exemplary embodiments.

[0040] Referring to FIG. 1, a fluid particle measurement device (100) may include a light source (105), an averaging unit (130), a fluid cell (140), and a detector (160).

[0041] The light source (105) may be a laser light generating device. According to exemplary embodiments, a pulsed laser beam (B) may be generated from the light source (105). For example, the light source (105) may include an Nd:YAG pulsed laser beam light source having a wavelength in the range of 500 nm to 600 nm (e.g., 532 nm). The type and light wavelength of the light source (105) may be appropriately changed in consideration of the target particle to be measured and beam shaping described below.

[0042] In some embodiments, laser light generated from a light source (105) may pass through an optical diaphragm (110). The diameter or output of the laser light or laser beam may be adjusted through the optical diaphragm (110). For example, the diameter or output of the laser beam may be reduced through the optical diaphragm (110). In some embodiments, the optical diaphragm (110) may include an attenuator.

[0043] A laser beam generated from a light source (105) or laser light processed through an optical aperture (110) may be incident on a beam splitter (120). In some embodiments, the laser beam may be reflected through a mirror (115) and incident on the beam splitter (120).

[0044] The beam splitter (120) can pass some of the incident laser beam and reflect some of the incident laser beam. Some of the laser beam can be reflected by the beam splitter (120) and irradiated to the flow cell (140). Some of the laser beam can pass through the beam splitter (120) and irradiate to the energy detection unit (125).

[0045] For example, as shown in Fig. 1, a pulsed laser beam (B) can be split into a first laser beam (B1) and a second laser beam (B2) by a beam splitter (120). The first laser beam (B1) and the second laser beam (B2) can be irradiated to a flow cell (140) and an energy detection unit (125), respectively.

[0046] The energy size of the second laser beam (B2) split by the beam splitter (120) can be measured through the energy detection unit (125). The energy size of the first laser beam (B1) incident on the flow cell (140) can be predicted or monitored with the energy measured through the energy detection unit (125).

[0047] The first laser beam (B1) can pass through a lens (135) before being irradiated to the flow cell (140). The focus of the first laser beam (B1) incident through the beam splitter (120) by the lens (135) can be adjusted to match the sample within the flow cell (140).

[0048] The lens (135) can adjust the irradiation area and / or focal length of the first laser beam (B1) incident on the flow cell (140). Accordingly, the detection performance for nanoparticles passing through the flow cell (140) can be improved.

[0049] The focal length can be appropriately adjusted by considering the collision point of the nanoparticles and the pulsed laser beam by the lens (135) and the refractive index of the sample introduced into the flow cell (140). For example, the distance between the lens (135) and the flow cell (140) can be adjusted by the control unit (180) described below according to the focal length.

[0050] A liquid sample containing particles to be measured (target particles) can be continuously supplied to the flow cell (140). As the liquid sample is supplied to the flow cell (140), a first laser beam (B1) is irradiated onto the flow cell (140), thereby enabling continuous real-time particle measurement.

[0051] For example, the liquid sample can be supplied through the cell inlet (50) and the liquid sample can be discharged from the cell outlet (55).

[0052] In some embodiments, the flow of the liquid sample may be controlled by the flow control unit (170). For example, the flow rate or volume of the liquid sample passing through the flow cell (140) may be controlled by the flow control unit (170). In one embodiment, the flow control unit (170) may be controlled together with the control unit (180).

[0053] As illustrated in FIG. 1, the flow control unit (170) may be located on the path of the cell outlet (55). In one embodiment, the flow control unit (170) may also be located on the path of the cell inlet (50).

[0054] When the first laser beam (B1) whose focal length is adjusted by the lens (135) collides with the flowing particles in the liquid sample within the flow cell (140), a plasma signal can be emitted.

[0055] According to exemplary embodiments, the fluid particle measurement device (100) may be a measurement device using a laser-induced breakdown detection (LIBD) method. For example, when a pulsed laser beam collides with a nanoparticle, the energy level of the nanoparticle becomes excited, and then releases energy while returning to the ground state (or excited state). The released energy causes plasma or shock waves to be generated in the nanoparticle.

[0056] As described above, the energy of the laser beam required to generate laser-induced plasma increases in the order of solid, liquid, and gas. Accordingly, by selecting a laser beam of an appropriate wavelength, laser-induced plasma can be generated by rupturing only solid particles within a liquid sample, for example, in an aqueous solution.

[0057] The laser-induced plasma may generate a shock wave or flash. The shock wave and / or flash may vary depending on the properties of the nanoparticles contained in the liquid sample. The number and / or size of the nanoparticles may be predicted / calculated through the shock wave and / or flash.

[0058] A detector (160) can be placed around the flow cell (140) to measure the shock wave and / or flash.

[0059] In some embodiments, the detector (160) may include a camera, such as a charge-coupled device (CCD) camera, which may be provided as a flash detector. In one embodiment, a filter may be positioned between the CCD camera and the flow cell (140) to allow flashes of a specific wavelength band to pass through.

[0060] In some embodiments, the detector (160) may include a piezoelectric sensor. The piezoelectric sensor may be provided as a shock wave detector. For example, the piezoelectric sensor may convert vibrations generated by the shock wave into electrical energy.

[0061] For example, the piezoelectric sensor may be positioned adjacent to the flow cell (140). In some embodiments, the shock wave detector and the scintillation detector described above may each be positioned adjacent to the flow cell (140).

[0062] In some embodiments, the laser beam passing through the flow cell (140) may be blocked by the beam stopper (150). Accordingly, the laser beam passing through the flow cell (140) may be prevented from being scattered or reflected, thereby disrupting detection / measurement in the flow cell (140).

[0063] The operation / measurement mechanism of the above-described fluid particle measuring device (100) can be controlled as a whole by the control unit (180).

[0064] The control unit (180) can control the light source (105) and the flow control unit (170). For example, the control unit (180) can control the period or generation time of the pulse laser beam (B) generated from the light source (105). In addition, the flow control unit (170) can control the period or flow time of the liquid sample supplied to the flow cell (140) by the control unit (180).

[0065] The control unit (180) may also move the lens (135) relative to the flow cell (140) to adjust the focal length of the first laser beam (B1).

[0066] The control unit (180) can process the signal transmitted from the detector (160) to generate information on nanoparticles contained in the liquid sample. For example, the control unit (180) includes a signal amplifier, a digital signal converter, a Fourier transform unit, etc., and can determine the type, size, or number of nanoparticles by utilizing the frequency components, amplitude, etc. of the shock wave.

[0067] A fluid particle measuring device (100) according to embodiments of the present disclosure may include an averaging unit (130). The averaging unit (130) may refer to a device or member that equalizes / flattens the waveform or intensity of a first laser beam (B1) irradiated to a fluid cell (140), or equalizes / flattens the intensity of plasma generated by the first laser beam (B1).

[0068] The averaging unit (130) can be placed in the supply area of ​​the incident laser beam or the measurement sample to the flow cell (140) including the lens (135) and the flow cell (140), as indicated by the dotted line in FIG. 1.

[0069] The structure and operation of the averaging unit (130) will be described in more detail later with reference to FIGS. 5 to 8.

[0070] Fig. 2 is a schematic diagram for explaining the shape in which a laser beam is incident on a flow cell in a flow particle measuring device according to a comparative example. Figs. 3 and 4 are graphs for explaining the progress profile of a laser beam in a flow particle measuring device according to a comparative example. Figs. 2 to 4 explain the shape of the laser beam incident when the averaging unit (130) is omitted in the flow particle measuring device described with reference to Fig. 1.

[0071] In FIGS. 2 to 4, the Z direction may be the direction in which the laser beam travels. The X direction may be the longitudinal direction of the flow cell (140), and the Y direction may be the width direction of the flow cell (140). The Y direction may substantially coincide with the direction of the intensity of the laser beam. The above-described direction definitions are equally applied to subsequent drawings.

[0072] Referring to FIG. 2, as described above, a laser beam (e.g., the first laser beam (B1)) passes through a lens (135), and a focal region (FR) can be formed where it collides with nanoparticles (60) included in a flow cell (140).

[0073] Referring to FIGS. 3 and 4, the intensity of the laser beam can be supplied in a peak-shaped waveform according to, for example, a Gaussian distribution.

[0074] As shown in Fig. 3, for example, the intensity of the laser beam may be supplied in a peak shape even in the detection area (DR) observed by the CCD camera. As shown in the form of a contour line in Fig. 4, the intensity of the laser beam may be increased in the area marked B compared to the areas marked A and C.

[0075] Accordingly, a deviation in the energy distribution occurs in the detection region (DR), and a deviation in the intensity of the plasma generated in the flow cell (140) may occur. Therefore, a deviation in the intensity of the detected plasma occurs, and a uniform detection intensity may not be provided in the detection region (DR).

[0076] Fig. 5 is a schematic diagram illustrating a form in which a laser beam is incident on a flow cell in a flow particle measurement device according to exemplary embodiments. Figs. 6 and 7 are graphs illustrating a propagation profile of a laser beam in a flow particle measurement device according to exemplary embodiments.

[0077] Referring to FIG. 5, the averaging unit (130) may include a beam shaping unit (137). In some embodiments, the beam shaping unit (137) may be positioned between the lens (135) and the flow cell (140).

[0078] Referring to FIGS. 6 and 7, the intensity profile of the laser beam in the detection area (DR) can be flattened by the beam shaping unit (137). According to exemplary embodiments, the curvature of the peak area of ​​the laser beam can be reduced by the beam shaping unit (137).

[0079] In some embodiments, as illustrated in FIG. 6, the laser beam intensity may be flattened in the detection area (DR) by the beam shaping unit (137), and may be maintained in an inclined shape outside the detection area (DR). In one embodiment, pointed ear-shaped protrusions may be formed at both ends of the detection area (DR). Alternatively, the laser beam may be deformed into a trapezoidal shape with a flat upper edge in the detection area (DR) by the beam shaping unit (137) and supplied to the flow cell (140).

[0080] The term "trapezoid" as used in this application is used to encompass a shape in which the upper and lower sides are substantially flat and the side sides have curved shapes.

[0081] In some embodiments, as illustrated in FIG. 7, the beam shaping unit (137) may shape the laser beam to have a substantially rectangular intensity profile. For example, the upper edge of the rectangular profile may represent the laser beam in a substantially flat detection area (DR).

[0082] As described above, the variation in laser beam intensity can be eliminated or reduced by the beam shaping unit (137), thereby also eliminating or reducing the variation in plasma intensity occurring in the detection area (DR) of the flow cell (140). Accordingly, the variation in detection frequency in the detection area (DR) can be reduced, and the reliability of measurement of the number / size of particles can be improved.

[0083] In some embodiments, the beam shaping unit (137) may include a partially reflective mirror. For example, the partially reflective mirror may have high reflectivity at the center of the laser beam and low reflectivity at both ends of the laser beam. Accordingly, the intensity at the center of the laser beam may be flattened.

[0084] In some embodiments, the beam shaping unit (137) may include a diffractive optical element (DOE) having a polarizing structure. For example, local polarization of a portion of light incident on the detection region (DR) through the beam shaping unit (137) may be performed, thereby flattening the intensity.

[0085] In some embodiments, the beam shaping portion (137) may be provided integrally with the lens (135). For example, a lens portion including an aspherical portion for flattening the laser beam may be included in the lens (135).

[0086] In addition to the examples described above, an optical device (metalens, deflector, etc.) capable of flattening the center of a laser beam as a beam shaping unit (137) may be used without any special limitation.

[0087] FIG. 8 is a schematic cross-sectional view showing an averaging portion of a fluid particle measuring device according to some embodiments.

[0088] Referring to FIG. 8, the averaging section (130) may be included in the flow cell (140) in the form of a partition wall (139).

[0089] According to exemplary embodiments, the diameter of the laser beam can change from the incident surface to the exit surface of the flow cell (140), and a flow space (FS) within the flow cell (140) can be formed according to the change in the diameter.

[0090] In some embodiments, as illustrated in FIG. 8, a partition wall (139) may be included within the flow cell (140) to form a flow space (FS) of the liquid sample according to the diameter of the laser beam. In one embodiment, the cross-section of the flow space (FS) may have a bow tie shape due to the partition wall (139).

[0091] In the focal region of the laser beam, the size (width or height) of the flow space (FS) can be reduced. Accordingly, in regions where the laser beam is narrow and strong, the number of particles that can collide with the laser beam can be reduced.

[0092] The size of the flow space (FS) can be increased in the outer region of the laser beam's focus area. Accordingly, as the size of the laser beam increases, the number of particles that can collide with the laser beam can increase in the region of low intensity.

[0093] Therefore, the plasma generation frequency and intensity can be equalized throughout the detection area (DR) of the flow cell (140).

Claims

1. A light source that generates a laser beam; A flow cell through which a liquid sample containing particles passes; A detector that detects a signal caused by plasma generated when the laser beam collides with the particles; and A fluid particle measuring device comprising an averaging section for reducing the frequency and intensity deviation of the plasma.

2. A fluid particle measuring device according to claim 1, wherein the averaging section includes a beam shaping section that flattens a peak area of ​​the laser beam incident on the fluid cell.

3. In claim 2, further comprising a lens disposed between the light source and the flow cell, A fluid particle measuring device, wherein the beam forming unit is disposed between the fluid cell and the lens.

4. In claim 3, further comprising a lens disposed between the light source and the flow cell, A fluid particle measuring device in which the beam forming unit is integrated with the lens.

5. A fluid particle measuring device according to claim 1, wherein the averaging unit is included within the fluid cell.

6. A fluid particle measuring device according to claim 5, wherein the averaging section includes a partition wall that defines a flow space of the liquid sample within the flow cell.

7. A fluid particle measuring device according to claim 6, wherein the fluid space has a shape that reflects a change in the diameter of the laser beam incident on the fluid cell.

8. A fluid particle measuring device according to claim 6, wherein the fluid space has a cross-section in the shape of a bow tie.

9. A step of continuously supplying a liquid sample containing target particles to a flow cell; A step of generating plasma from the target particles by irradiating a laser beam onto the fluid cell; a step of equalizing the frequency and intensity of the plasma; and A method for measuring fluid particles, comprising a step of detecting a detection signal induced from the plasma and deriving information on the target particles.

10. A method for measuring fluid particles according to claim 9, wherein the step of leveling the frequency and intensity of the plasma includes leveling the peak area of ​​the laser beam incident on the fluid cell.

11. A method for measuring moving particles according to claim 10, wherein flattening the peak area of ​​the incident laser beam includes converting a laser beam having a Gaussian distribution shape into a trapezoidal or rectangular laser beam.

12. A method for measuring fluid particles according to claim 9, wherein the step of equalizing the frequency and intensity of the plasma includes limiting the flow space of the liquid sample within the flow cell according to a change in the diameter of the laser beam incident on the flow cell.

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