Flowing particle measurement equipment and methods

Abstract

A flow particle measurement apparatus and a flow particle measurement method are disclosed. The flow particle measurement apparatus includes: a light source for generating a laser beam; a flow cell through which a liquid sample including particles passes; a detector for detecting the signal caused by plasma generated when the laser beam collides with the particles; and an averaging element for reducing deviations in the frequency and intensity of the plasma.

Description

Technical Field

[0001] This invention relates to a device and method for measuring flowing particles. More specifically, this invention relates to a device and method for measuring flowing particles that include a light source and a flow cell. Background Technology

[0002] For example, chemical materials such as etchants, rinsing solutions, and developer solutions are used in the manufacturing processes of electronic devices such as display devices and semiconductor devices. As the critical dimensions of electronic devices decrease, high-purity chemical materials are used.

[0003] For example, when chemical materials contain nanoscale impurity particles, the yield and reliability of electronic device manufacturing processes may be reduced. For instance, it may be necessary to detect and manage particles with sizes of 100 nm or smaller, 50 nm or smaller, or even 10 nm in high-purity chemicals used in the handling of electronic devices.

[0004] Particles can be detected in the chemical material within a continuous processing unit while the chemical material is continuously fed into the flow cell. A detection signal can be generated by a light source while particles are supplied / transferred to the flow cell.

[0005] However, variations in the waveform and intensity of the detection light generated from the light source can occur depending on the region. In such cases, the frequency and intensity of the detection signal generated from the particles may also change. For example, when a particle structure is excited by detection light, it may cause inhomogeneities in the intensity and frequency of the generated shock wave, leading to a decrease in detection reliability and resolution.

[0006] For example, Korean Patent Publication No. 10-1504061 discloses a sample measurement system using a laser light source. Summary of the Invention

[0007] Technical issues

[0008] According to one aspect of the present invention, a flow particle measuring device with improved measurement accuracy and reliability is provided.

[0009] According to one aspect of the present invention, a method for measuring flowing particles with improved measurement accuracy and reliability is provided.

[0010] means for solving problems

[0011] 1. A flow particle measurement device, comprising: 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 from a plasma generated by collisions between the laser beam and the particles; and an averaging element that reduces deviations in the frequency and intensity of the plasma.

[0012] 2. The flow particle measuring device according to 1 above, wherein the averaging element includes a beam shaping element that flattens the peak region of the laser beam incident on the flow cell.

[0013] 3. The flow particle measuring device according to 2 above further includes a lens disposed between the light source and the flow cell, wherein the beam shaping element is disposed between the flow cell and the lens.

[0014] 4. The flow particle measuring device according to 3 above further includes a lens disposed between the light source and the flow cell, wherein the beam shaping element is integrated with the lens.

[0015] 5. The flow particle measuring device according to claim 1, wherein the averaging element is included in the flow cell.

[0016] 6. The flow particle measuring device according to claim 5, wherein the averaging element includes a partition wall defining the flow space of the liquid sample in the flow cell.

[0017] 7. The flow particle measuring device according to 6 above, wherein the flow space has a shape that reflects the change in the diameter of the laser beam incident on the flow cell.

[0018] 8. The flow particle measuring device according to 6 above, wherein the flow space has a bow-shaped cross-section.

[0019] 9. A method for measuring flowing particles, comprising: continuously supplying a liquid sample containing target particles to a flow cell; generating plasma from the target particles by irradiating the flow cell with a laser beam; averaging the frequency and intensity of the plasma; and detecting a detection signal generated from the plasma to obtain information about the target particles.

[0020] 10. The method for measuring flowing particles according to 9 above, wherein averaging the frequency and intensity of the plasma includes flattening the peak region of the laser beam incident on the flow cell.

[0021] 11. The method for measuring flowing particles according to 10 above, wherein flattening the peak region of the incident laser beam includes converting a laser beam in the form of a Gaussian distribution into a laser beam in the form of a trapezoidal or rectangular shape.

[0022] 12. The method for measuring flowing particles according to 9 above, wherein averaging the frequency and intensity of the plasma includes defining the flow space of the liquid sample in the flow cell based on the change in the diameter of the laser beam incident on the flow cell.

[0023] Invention Effects

[0024] The flowing particle measurement apparatus according to an embodiment of the present invention may include an averaging element for homogenizing the intensity of laser light incident from a laser source. The laser intensity at the camera observation area in the flow cell can be flattened by the averaging element. Therefore, the accuracy and reliability of particle measurement can be improved, while reducing the deviation of plasma detection intensity according to the region in the camera observation area.

[0025] In some implementations, an averaging element may be included in the flow cell. The flow space within the flow cell can be matched by the averaging element according to the diameter / intensity of the laser to homogenize the plasma intensity / frequency in the flow space. Attached Figure Description

[0026] Figure 1 This is a schematic block diagram illustrating a flow particle measuring device according to an example embodiment.

[0027] Figure 2 This is a schematic diagram illustrating the form of laser incident on the flow cell in a flow particle measuring device according to a comparative example.

[0028] Figure 3 and Figure 4 It is a graph used to describe the travel distribution of the laser in the flow particle measuring device according to the comparative example.

[0029] Figure 5 This is a schematic diagram illustrating the form of laser incident on a flow cell in a flow particle measuring apparatus according to an example embodiment.

[0030] Figure 6 and Figure 7 It is a graph used to describe the travel distribution of the laser in a flow particle measuring device according to an example embodiment.

[0031] Figure 8 This is a schematic cross-sectional view showing the averaging element of a flow particle measuring device according to some embodiments. Detailed Implementation

[0032] An embodiment of the present invention provides a flow particle measuring device including a flow cell and a light source.

[0033] A flowing particle measurement device can be a device that calculates the number and size of flowing particles by detecting the shock wave or scintillation caused by the plasma generated when a laser beam collides with flowing particles. In an exemplary embodiment, the size and frequency (number) of nanoscale particles of 100 nm or smaller, 90 nm or smaller, 80 nm or smaller, 70 nm or smaller, 50 nm or smaller, 40 nm or smaller, 30 nm or smaller, 20 nm or smaller, or 10 nm or smaller can be measured by the flowing particle measurement device.

[0034] In the following description, embodiments of the invention will be described in more detail with reference to the accompanying drawings. However, since the embodiments provided in this specification offer some preferred examples and are used to further understand the technical concepts of the invention and the foregoing content of the invention, the invention should not be construed as being limited to the contents described in these embodiments.

[0035] The terms “first,” “second,” “top surface,” “bottom surface,” “upper,” “lower,” etc., are not intended to specify absolute positions in this document, but are used in a relative sense to distinguish different elements or different positions between different elements.

[0036] Figure 1 This is a schematic block diagram illustrating a flow particle measuring device according to an example embodiment.

[0037] refer to Figure 1 The flow particle measuring device 100 may include a light source 105, an averaging element 130, a flow cell 140, and a detector 160.

[0038] Light source 105 may be a laser generating device. In an example embodiment, a pulsed laser beam B can be generated from light source 105. For example, light source 105 may include an Nd:YAG pulsed laser beam source with a wavelength in the range of 500 nm to 600 nm (e.g., 532 nm). The type and optical wavelength of light source 105 may be appropriately varied, taking into account the particles to be measured and the beam shaping, as described below.

[0039] In some embodiments, the laser generated from the light source 105 can pass through an optical aperture (diaphragm) 110. The diameter or power of the laser or laser beam can be adjusted by the optical aperture (diaphragm) 110. For example, the diameter or power of the laser beam can be reduced by the optical aperture (diaphragm) 110. In some embodiments, the optical aperture 110 may include an attenuator.

[0040] A laser beam generated from light source 105 or processed through optical aperture 110 can be incident on beam splitter 120. In some embodiments, the laser beam can be reflected by mirror 115 and incident on beam splitter 120.

[0041] Beam splitter 120 allows some incident laser beams to pass through and reflects some laser beams. Some of the laser beams can be reflected by beam splitter 120 and illuminate flow cell 140. Some laser beams can pass through beam splitter 120 to illuminate energy detector 125.

[0042] For example, such as Figure 1 As shown, the pulsed laser beam B can be split into a first laser beam B1 and a second laser beam B2 by the beam splitter 120. The first laser beam B1 and the second laser beam B2 can respectively irradiate the flow cell 140 and the energy detector 125.

[0043] The energy level of the second laser beam B2, which is split by the beam splitter 120, can be measured by the energy detector 125. The energy measured by the energy detector 125 can be used to predict or monitor the energy level of the first laser beam B1 incident on the flow cell 140.

[0044] The first laser beam B1 can pass through the lens 135 before being irradiated into the flow cell 140. The focal point of the first laser beam B1 incident through the beam splitter 120 can be adjusted by the lens 135 to fit the sample into the flow cell 140.

[0045] Lens 135 can adjust the irradiation area and / or focal length of the first laser beam B1 incident on the flow cell 140. Therefore, the detection performance of nanoparticles passing through the flow cell 140 can be improved.

[0046] Considering the collision point between the nanoparticles and the pulsed laser beam, as well as the refractive index of the sample introduced into the flow cell 140, the focal length can be appropriately adjusted by the lens 135. For example, the distance between the lens 135 and the flow cell 140 can be adjusted by the controller 180 according to the focal length, as described later.

[0047] A liquid sample containing the particles to be measured (target particles) can be continuously supplied to the flow cell 140. When the liquid sample is supplied to the flow cell 140, the first laser beam B1 can irradiate the flow cell 140, enabling continuous real-time particle measurement.

[0048] For example, liquid samples can be supplied through pool inlet 50 and discharged from pool outlet 55.

[0049] In some embodiments, the flow rate of the liquid sample can be controlled by the flow controller 170. For example, the flow rate or velocity of the liquid sample passing through the flow cell 140 can be controlled by the flow controller 170. In some embodiments, the flow controller 170 can also be controlled by the controller 180.

[0050] like Figure 1As shown, the flow controller 170 can be located on the path of the pool outlet 55. In an embodiment, the flow controller 170 can be located on the path of the pool inlet 50.

[0051] When the first laser beam B1 collides with the flowing particles in the liquid sample in the flow cell 140, it can emit a plasma signal.

[0052] In an example implementation, the flowing 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 nanoparticle's energy level becomes excited, and then releases energy while returning to the ground (or excited) state. The released energy generates plasma or shock waves within the nanoparticle.

[0053] The energy of the laser beam required to generate laser-induced plasma increases sequentially for solids, liquids, and gases. Therefore, a laser beam of appropriate wavelength can be selected, and laser-induced plasma can be generated by breaking down solid particles in a liquid sample, such as an aqueous solution.

[0054] Laser-induced plasma can generate shock waves or flashes. The shock waves and / or flashes can vary depending on the physical properties of the nanoparticles contained in the liquid sample. The number and / or size of nanoparticles can be predicted / calculated using shock waves and / or flashes.

[0055] Detector 160 can be configured adjacent to flow cell 140 to measure shock waves and / or flashes.

[0056] In some embodiments, detector 160 may further include a camera, such as a CCD camera. The CCD camera 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.

[0057] In some implementations, detector 160 may include a piezoelectric sensor. The piezoelectric sensor may be provided as a shock wave detector. For example, a piezoelectric sensor can convert vibrations generated by a shock wave into electrical energy.

[0058] For example, the piezoelectric sensor can be positioned adjacent to the flow cell 140. In some embodiments, the aforementioned shock wave detector and flash detector can each be positioned adjacent to the flow cell 140.

[0059] In some implementations, the laser beam passing through the flow cell 140 can be blocked by the beam blocker 150. This prevents the laser beam passing through the flow cell 140 from being scattered or reflected, thus avoiding interference with detection / measurement in the flow cell 140.

[0060] The operation / measuring mechanism of the aforementioned flowing particle measuring device 100 can be fully adjusted by the controller 180.

[0061] The controller 180 can control the light source 105 and the flow controller 170. For example, the controller 180 can control the period or occurrence time of the pulsed laser beam B generated from the light source 105. In addition, the flow controller 170 can control the period or flow time of the liquid sample supplied to the flow cell 140 via the controller 180.

[0062] The controller 180 can move the lens 135 relative to the flow cell 140 to adjust the focal length of the first laser beam B1.

[0063] The controller 180 can process the signal transmitted from the detector 160 to generate information about the nanoparticles included in the liquid sample. For example, the controller 180 may include a signal amplifier, a digital signal converter, a Fourier transform, etc., and can determine the type, size, or quantity of nanoparticles by using the frequency components, amplitude, etc. of the shock wave.

[0064] The flow particle measuring device 100 according to an embodiment of the present invention may include an averaging element 130. The averaging element 130 may refer to a device or component for leveling / flattening the waveform or intensity of the first laser beam B1 irradiating the flow cell 140, or for leveling / flattening the intensity of the plasma generated by the first laser beam B1.

[0065] The averaging element 130 can be positioned 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. Figure 1 As shown by the dashed line in the image.

[0066] Please refer to later Figures 5 to 8 The structure and operation of the averaging element 130 are described in more detail.

[0067] Figure 2 This is a schematic diagram illustrating the form of laser incident on the flow cell in a flow particle measuring device according to a comparative example. Figure 3 and Figure 4 It is a graph used to describe the travel distribution of the laser in the flow particle measuring device according to the comparative example. Figures 2 to 4 Describes when from the reference Figure 1 The incident shape of the laser beam when the averaging element 130 is omitted in the described flow particle measuring device.

[0068] exist Figures 2 to 4In this diagram, the Z-direction can be the direction of travel of the laser beam. The X-direction can be the longitudinal direction of the flow cell 140, and the Y-direction can be the width direction of the flow cell 140. The Y-direction can be substantially consistent with the intensity direction of the laser beam. The above definitions of directions also apply to the following figures.

[0069] refer to Figure 2 As described above, the laser beam (e.g., the first laser beam B1) can pass through the lens 135 and can form a focused region FR that collides with the nanoparticles 60 included in the flow cell 140.

[0070] refer to Figure 3 and Figure 4 The intensity of the laser beam can be provided as, for example, a peak waveform according to a Gaussian distribution.

[0071] like Figure 3 As shown, for example, even within the detection area DR observed by the CCD camera, the intensity of the laser beam can be provided in the form of a peak. Figure 4 As shown, the intensity of the laser beam can be increased in the region indicated by B than in the regions indicated by A and C.

[0072] Therefore, deviations in energy distribution may occur in the detection region DR, and deviations in the intensity of the plasma generated in the flow cell 140 may also occur. Consequently, deviations in the intensity of the detected plasma may occur, and uniform detection intensity may not be provided in the detection region DR.

[0073] Figure 5 This is a schematic diagram illustrating the form of laser incident on a flow cell in a flow particle measuring apparatus according to an example embodiment. Figure 6 and Figure 7 It is a graph used to describe the travel distribution of the laser in a flow particle measuring device according to an example embodiment.

[0074] refer to Figure 5 The averaging element 130 may include a beam shaping element 137. In some embodiments, the beam shaping element 137 may be disposed between the lens 135 and the flow cell 140.

[0075] refer to Figure 6 and Figure 7 The laser beam intensity distribution in the detection region DR can be flattened by the beam shaping element 137. In an example embodiment, the curvature of the peak region of the laser beam can be reduced by the beam shaping element 137.

[0076] In some implementation schemes, such as Figure 6As shown, the beam shaping element 137 can flatten the intensity of the laser beam in the detection region DR and can maintain a tilted shape outside the detection region DR. In one embodiment, sharp ear-shaped protrusions can be formed at both ends of the detection region DR. Alternatively, the laser beam can be transformed into a trapezoidal shape with a flat upper side in the detection region DR by the beam shaping element 137 and supplied to the flow cell 140.

[0077] The term "trapezoidal" in this application is used to cover a shape whose upper and lower sides are substantially flat and whose sides have a curved shape.

[0078] In some implementation schemes, such as Figure 7 As shown, the laser beam can be transformed by the beam shaping element 137 to have a substantially rectangular intensity distribution. For example, the upper side of the rectangular profile can represent the laser beam in a substantially flat detection area DR.

[0079] As described above, deviations in laser beam intensity can be eliminated or reduced by the beam shaping element 137, and therefore deviations in plasma intensity generated in the detection region DR of the flow cell 140 can also be eliminated or reduced. Thus, deviations in the detection frequency in the detection region DR can be reduced, and the reliability of particle number / size measurement can be improved.

[0080] In some embodiments, the beam shaping element 137 may include a partial reflector. For example, the partial reflector may have high reflectivity at the center of the laser beam and low reflectivity at both ends of the laser beam. Thus, the intensity can be flattened at the center of the laser beam.

[0081] In some embodiments, beam shaping element 137 may include a diffractive optical element (DOE) with a polarization structure. For example, local polarization of a portion of the light incident on the detection region DR through beam shaping element 137 may be performed to flatten the intensity.

[0082] In some embodiments, the beam shaping element 137 may be provided integrally with the lens 135. For example, a lens element including an aspherical portion may be included in the lens 135 to flatten the laser beam.

[0083] In addition to the examples above, optical devices (superlenses, deflectors, etc.) that can flatten the center of a laser beam can be used as beam shaping elements 137 without any particular limitation.

[0084] Figure 8 This is a schematic cross-sectional view showing the averaging element of a flow particle measuring device according to some embodiments.

[0085] refer to Figure 8The averaging element 130 may be included in the flow cell 140 in the form of a partition wall 139.

[0086] In the example implementation, the diameter of the laser beam can be varied from the incident surface to the exit surface of the flow cell 140, and the flow space FS in the flow cell 140 can be formed according to the change in diameter.

[0087] In some implementation schemes, such as Figure 8 As shown, the partition wall 139 may be included in the flow cell 140, such that the flow space FS of the liquid sample can be formed according to the diameter of the laser beam. In one embodiment, the cross-section of the flow space FS may have a bow shape through the partition wall 139.

[0088] The dimensions (width or height) of the flow space FS can be reduced in the focusing region of the laser beam. Therefore, in regions where the laser beam is narrow and intense, the number of particles capable of colliding with the laser beam can be reduced.

[0089] The size of the flow space FS can be increased in the region outside the focusing region of the laser beam. Therefore, 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.

[0090] Therefore, the frequency and intensity of plasma generation can be averaged throughout the entire detection region DR of the flow cell 140.

Claims

1. A device for measuring flowing particles, comprising: A light source that generates a laser beam; A flow cell through which a liquid sample containing particles passes; A detector that detects signals from plasma generated by the collision of the laser beam with the particles; and An averaging element that reduces the deviation in frequency and intensity of the plasma.

2. The flow particle measuring apparatus according to claim 1, wherein the averaging element comprises a beam shaping element that flattens the peak region of the laser beam incident on the flow cell.

3. The flow particle measuring device according to claim 2 further includes a lens disposed between the light source and the flow cell, wherein the beam shaping element is disposed between the flow cell and the lens.

4. The flowing particle measuring device according to claim 3 further includes a lens disposed between the light source and the flow cell. The beam shaping element is integrated with the lens.

5. The flow particle measuring device according to claim 1, wherein the averaging element is included in the flow cell.

6. The flow particle measuring apparatus of claim 5, wherein the averaging element includes a partition wall defining the flow space of the liquid sample in the flow cell.

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

8. The flow particle measuring device according to claim 6, wherein the flow space has a bow-shaped cross-section.

9. A method for measuring flowing particles, comprising: A liquid sample containing the target particles is continuously supplied to the flow cell; Plasma is generated from the target particles by irradiating the flow cell with a laser beam. The frequency and intensity of the plasma are averaged. as well as The detection signal generated by the plasma is detected to obtain information about the target particles.

10. The method for measuring flowing particles according to claim 9, wherein averaging the frequency and intensity of the plasma comprises flattening the peak region of the laser beam incident on the flow cell.

11. The method for measuring flowing particles according to claim 10, wherein flattening the peak region of the incident laser beam comprises converting a laser beam in the form of a Gaussian distribution into a laser beam in the form of a trapezoidal or rectangular shape.

12. The method for measuring flowing particles according to claim 9, wherein averaging the frequency and intensity of the plasma includes defining the flow space of the liquid sample in the flow cell according to the variation in the diameter of the laser beam incident on the flow cell.

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