A photoresist particle counter

Abstract

This invention discloses a photoresist particle counter, comprising a laser emission module, a fluid flow channel module, a focusing lens, a signal processing module, and a position adjustment module. The laser emission module outputs a parallel light beam, which passes sequentially through the fluid flow channel module and the focusing lens before being projected onto the signal processing module. The position adjustment module is fixedly connected to the focusing lens and adjusts the distance between the focusing lens and the signal processing module, thereby changing the size of the focused light spot projected onto the signal processing module. The signal processing module receives the optical signal passing through the fluid flow channel module and outputs a corresponding electrical signal to obtain the number and size of particles flowing through the fluid flow channel module. This photoresist particle counter improves the light energy utilization rate of the photoelectric receiving process and ensures the counting accuracy and the detection accuracy of the true particle size.

Description

Technical Field

[0001] This utility model relates to the field of particle counter technology, and in particular to a photoresist particle counter. Background Technology

[0002] A particle counting device is an instrument used to detect the size distribution and quantity of tiny particles in a medium. Among them, optical counting is currently the most widely used particle counting method, and optical obscuration particle counters are now widely used to determine the size and quantity of micron-sized particles.

[0003] However, in the optical path design of traditional photoresist particle counters, due to the diffraction characteristics of light, the collimated laser beam still inevitably has a large divergence angle after passing through a single lens, resulting in poor system stability. Furthermore, the photoelectric receiving process of photoresist particle counters suffers from poor beam quality and small area, leading to low light energy utilization and failing to guarantee high particle counting accuracy and detection precision. Utility Model Content

[0004] This utility model embodiment provides an optical path design to improve the beam quality of a photoresist particle counter, thereby increasing light energy utilization and ensuring the counting accuracy and true size detection accuracy of the particles.

[0005] This utility model provides a photoresist particle counter, including a laser emission module, a fluid flow channel module, a focusing lens, a signal processing module, and a position adjustment module;

[0006] The laser emission module, the fluid flow channel module, the focusing lens, and the signal processing module are arranged in sequence. The laser emission module is used to output a parallel beam, and the parallel beam passes through the fluid flow channel module and the focusing lens in sequence and is projected onto the signal processing module.

[0007] The position adjustment module is fixedly connected to the focusing lens. The position adjustment module is used to adjust the distance between the focusing lens and the signal processing module, thereby changing the size of the focused spot projected onto the signal processing module.

[0008] The signal processing module receives the optical signal passing through the fluid flow channel module and outputs the corresponding electrical signal to obtain the number and particle size of the particles flowing through the fluid flow channel module.

[0009] Optionally, the focusing lens includes a sleeve component, and the position adjustment module includes a screw component;

[0010] The sleeve component of the focusing lens is mechanically connected to the screw component of the position adjustment module via threads.

[0011] Optionally, the focal length of the focusing lens is in the range of 70-80mm.

[0012] Optionally, the focusing lens is a plano-convex lens.

[0013] Optionally, the laser emission module includes a light source with coincident optical axes and at least two collimating lenses;

[0014] The light source is used to output an initial beam;

[0015] Each of the collimating lenses is located sequentially on the propagation path of the initial beam, and each of the collimating lenses is used to collimate the initial beam into the parallel beam.

[0016] Optionally, the at least two collimating lenses include a first collimating lens and a second collimating lens;

[0017] The first collimating lens is located on the side of the second collimating lens closer to the light source;

[0018] The focal length of the first collimating lens is 10-14mm, and the focal length of the second collimating lens is 18-22mm.

[0019] Optionally, the first collimating lens is a plano-convex lens.

[0020] Optionally, the second collimating lens is an aspherical lens.

[0021] Optionally, the signal processing module includes a photodetector and a photodetector circuit;

[0022] The photodetector is used to receive the optical signal passing through the fluid flow channel module and output the corresponding electrical signal;

[0023] The photoelectric detection circuit is electrically connected to the photodetector. The photoelectric detection circuit is used to analyze and process the electrical signal to determine the number and size of particles flowing through the fluid channel module.

[0024] Optionally, the fluid flow direction set in the fluid channel module is perpendicular to the propagation path of the parallel beam.

[0025] This invention provides a photoresist particle counter, which includes a laser emission module, a fluid flow channel module, a focusing lens, a signal processing module, and a position adjustment module. The laser emission module, fluid flow channel module, focusing lens, and signal processing module are arranged sequentially. The laser emission module outputs a parallel beam of light, which passes through the fluid flow channel module and the focusing lens sequentially, and is projected onto the signal processing module. The position adjustment module is fixedly connected to the focusing lens and is used to adjust the distance between the focusing lens and the signal processing module, thereby changing the size of the focused spot projected onto the signal processing module. The signal processing module receives the optical signal passing through the fluid flow channel module and outputs a corresponding electrical signal to obtain the number and particle size of particles flowing through the fluid flow channel module. This optical path design for improving the beam quality of a photoresist particle counter adds a movable focusing lens between the fluid flow channel module and the signal processing module. The distance between the focusing lens and the signal processing module can be varied, thus allowing for a variable size of the focused spot projected onto the signal processing module. This ensures that as much of the light signal passing through the fluid flow channel module as possible is received by the signal processing module, improving the beam quality and beam area received by the signal processing module. This enhances the light energy utilization rate of the photoelectric receiving process, ensures the counting accuracy and true size detection accuracy of the particles, and improves the overall system stability of the photoresist particle counter. It achieves the effects of improved beam quality and adjustable focused spot size, making it suitable for detecting the number and size of more types of particles. Furthermore, the smaller divergence angle of the parallel beam output by the laser emission module also contributes to better stability of the light signal received by the signal processing module.

[0026] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of a photoresist particle counter provided in an embodiment of this utility model. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] Figure 1 This is a schematic diagram of the structure of a photoresist particle counter provided in an embodiment of this utility model, as shown below. Figure 1 As shown, the photoresist particle counter includes a laser emission module 10, a fluid flow channel module 20, a focusing lens 30, a signal processing module 40, and a position adjustment module 50. The laser emission module 10, fluid flow channel module 20, focusing lens 30, and signal processing module 40 are placed sequentially. The laser emission module 10 outputs a parallel beam of light, which passes through the fluid flow channel module 20 and the focusing lens 30 sequentially and is projected onto the signal processing module 40. The position adjustment module 50 is fixedly connected to the focusing lens 30 and is used to adjust the distance between the focusing lens 30 and the signal processing module 40, thereby changing the size of the focused spot projected onto the signal processing module 40. After receiving the optical signal passing through the fluid flow channel module 20, the signal processing module 40 performs photoelectric conversion and outputs a corresponding electrical signal. Based on the acquired electrical signal, it outputs the corresponding number and particle size of particles.

[0032] Specifically, this optically impermeable particle counter calculates the number and size of particles by detecting the light intensity attenuation caused by particles passing through a parallel light beam. The working principle is as follows: A parallel light beam is output from the laser emission module 10 and illuminates the fluid flow channel module 20. When there are no particles in the measurement area of ​​the fluid flow channel module 20, the entire light beam passes through the measurement area and, after passing through the focusing lens 30, is finally received by the signal processing module 40. When there are particles in the measurement area of ​​the fluid flow channel module 20, the light beam is blocked by the particles, and the light flux received by the focusing lens 30 and the signal processing module 40 is reduced. If the shape and optical properties of the particles remain unchanged and they pass through the light beam along the same path, the reduction in transmitted light flux received by the signal processing module 40 is proportional to the square of the particle size. The particle size can be calculated from the reduction ratio of light flux; for example, the particle size can be represented by the particle diameter. Optionally, the fluid flow direction set in the fluid flow channel module 20 is perpendicular to the propagation path of the parallel beam. That is, by using an appropriate method, the fluid in the fluid flow channel module 20 is made perpendicular to the direction of travel of the parallel beam output by the laser emission module 10, and flows through the measurement area in the fluid flow channel module 20. Simultaneously, the electrical signal output by the signal processing module 40 is continuously measured. When there are no particles in the fluid flowing through the measurement area of ​​the fluid flow channel module 20, the electrical signal output by the signal processing module 40 remains at a constant value. When particles pass through the measurement area of ​​the fluid flow channel module 20, the electrical signal output by the signal processing module 40 decreases. After the particles pass through, the electrical signal output by the signal processing module 40 returns to a constant value. Therefore, whenever a particle flows through the measurement area, the electrical signal output by the signal processing module 40 generates a pulse. The number of pulses is related to the number of particles, and the pulse height is related to the size of the particles. Each pulse corresponds to a particle size. After the measurement continues for a period of time, the number and size of all the measured particles are counted. At the same time, the volume of fluid flowing through the measurement area is measured, and the number and size of particles contained in a unit volume can be calculated.

[0033] Furthermore, it should be noted that a movable focusing lens 30 is added between the fluid flow channel module 20 and the signal processing module 40. The distance between the focusing lens 30 and the signal processing module 40 can be varied, thereby allowing the size of the focused light spot projected onto the signal processing module 40 to vary. This ensures that as much of the light signal passing through the fluid flow channel module 20 as possible is received by the signal processing module 40, which is beneficial for improving the beam quality and beam area received by the signal processing module 40, and increasing the light energy utilization rate of the photoelectric reception process. The position adjustment module 50 is fixedly connected to the focusing lens 30. For example, the focusing lens 30 includes a sleeve component, and the position adjustment module 50 includes a screw component; the sleeve component of the focusing lens 30 is mechanically connected to the screw component of the position adjustment module 50 via threads. Of course, the mechanical connection structure between the position adjustment module 50 and the focusing lens 30 can also be other types, and can be selected and set according to actual needs.

[0034] The technical solution in this embodiment of the invention, which improves the beam quality of the photoresist particle counter, involves adding a movable focusing lens between the fluid flow channel module and the signal processing module. The distance between the focusing lens and the signal processing module is variable, thereby allowing the size of the focused spot projected onto the signal processing module to vary. This ensures that as much of the light signal passing through the fluid flow channel module as possible is received by the signal processing module, which is beneficial for improving the beam quality and beam area received by the signal processing module, increasing the light energy utilization rate of the photoelectric receiving process, ensuring the counting accuracy of particles and the detection accuracy of the true particle size, improving the overall operational stability of the photoresist particle counter system, achieving the effects of improved beam quality and adjustable focused spot size, and also enabling adjustable optical path. This makes it applicable to the detection of the number and size of more types of particles. Furthermore, the smaller divergence angle of the parallel beam output by the laser emission module also makes the stability of the light signal received by the signal processing module better.

[0035] Optionally, continue to refer to Figure 1 The signal processing module 40 includes a photodetector 41 and a photodetector circuit 42. The photodetector 41 is used to receive the light signal passing through the fluid flow channel module 20, perform photoelectric conversion, and output the corresponding electrical signal. The photodetector circuit 42 is electrically connected to the photodetector 41 and is used to analyze and process the electrical signal, and output the corresponding number and size of particles based on the acquired electrical signal.

[0036] Specifically, a movable focusing lens 30 is added between the fluid flow channel module 20 and the signal processing module 40. The position of the focusing lens 30 is adjustable, thereby adjusting the size of the focused light spot projected onto the signal processing module 40. In this way, by reasonably adjusting the position of the focusing lens 30, the distance between the focusing lens 30 and the signal processing module 40 can be equal to the focal length of the focusing lens 30, that is, the signal processing module 40 is positioned at the focal point of the focusing lens 30, thus ensuring the reception and utilization rate of the light beam.

[0037] Optionally, continue to refer to Figure 1 The focal length range of the focusing lens 30 is 70-80mm. That is, the focal length range of the focusing lens 30 can be 75±5 mm.

[0038] Optionally, continue to refer to Figure 1 The focusing lens 30 is a plano-convex lens.

[0039] Specifically, the plano-convex lens has a fixed and positive focal length, which can focus the light beam passing through the fluid channel module 20 to a single focal point. At the same time, it has a smaller spherical aberration in a specific direction (planar side) and better optical performance. The plano-convex lens has specific characteristics such as high light-gathering efficiency, good aberration control, and wide applicability.

[0040] Optionally, continue to refer to Figure 1 The laser emission module 10 includes a light source 11 with the optical axis coincident and at least two collimating lenses 12; the light source 11 is used to output an initial beam; each collimating lens 12 is located sequentially on the propagation path of the initial beam, and each collimating lens 12 is used to collimate the initial beam into a parallel beam.

[0041] Specifically, in this embodiment, at least two collimating lenses 12 are used. The at least two collimating lenses 12 can collimate the initial beam output by the light source 11, reduce the divergence angle of the initial beam output by the light source 11, and reduce the divergence angle of the collimated parallel beam to one-tenth of that in the case of a single lens. This can also make the stability of the optical signal received by the signal processing module 40 better and improve the overall operational stability of the optical resist particle counter system.

[0042] Optionally, continue to refer to Figure 1 At least two collimating lenses 12 include a first collimating lens 121 and a second collimating lens 122; the first collimating lens 121 is located on the side of the second collimating lens 122 closer to the light source 11; the focal length of the first collimating lens 121 is 10-14mm, and the focal length of the second collimating lens 122 is 18-22mm.

[0043] Specifically, the initial beam output from the light source 11 is collimated by a dual-lens collimation system to become a parallel beam with a very small divergence angle, facilitating its subsequent emission into the fluid flow channel module 20. For example, the focal length of the first collimating lens 121 can be 12 ± 2 mm, and the focal length of the second collimating lens 122 can be 20 ± 2 mm. For example, the first collimating lens 121 is a plano-convex lens. For example, the second collimating lens 122 is an aspherical lens.

[0044] Furthermore, based on this, taking an object-side focal length of 10mm, an aperture of 6mm, and using BK7 (glass type) as the material and a wavelength of 1310nm as an example, parameters were set and optimized to obtain lens data for simulation. It can be observed that after passing through the dual-lens collimation system, the beam divergence angle RMS radius = 0.143mrad. The traditional single-lens collimation system using the same material produces a divergence angle of 2.52mrad after simulation, meaning the beam quality obtained by this design is more than ten times better.

[0045] It should be understood that the various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.

[0046] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A photoresist particle counter, characterized in that, It includes a laser emission module, a fluid flow channel module, a focusing lens, a signal processing module, and a position adjustment module; The laser emission module, the fluid flow channel module, the focusing lens, and the signal processing module are arranged in sequence. The laser emission module is used to output a parallel beam, and the parallel beam passes through the fluid flow channel module and the focusing lens in sequence and is projected onto the signal processing module. The position adjustment module is fixedly connected to the focusing lens. The position adjustment module is used to adjust the distance between the focusing lens and the signal processing module, thereby changing the size of the focused spot projected onto the signal processing module. The signal processing module receives the optical signal passing through the fluid flow channel module and outputs the corresponding electrical signal to obtain the number and particle size of the particles flowing through the fluid flow channel module.

2. The photoresist particle counter according to claim 1, characterized in that, The focusing lens includes a sleeve component, and the position adjustment module includes a screw component; The sleeve component of the focusing lens is mechanically connected to the screw component of the position adjustment module via threads.

3. The photoresist particle counter according to claim 1, characterized in that, The focal length of the focusing lens is 70-80mm.

4. The photoresist particle counter according to claim 1, characterized in that, The focusing lens is a plano-convex lens.

5. The photoresist particle counter according to claim 1, characterized in that, The laser emission module includes a light source with coincident optical axes and at least two collimating lenses; The light source is used to output an initial beam; Each of the collimating lenses is located sequentially on the propagation path of the initial beam, and each of the collimating lenses is used to collimate the initial beam into the parallel beam.

6. The photoresist particle counter according to claim 5, characterized in that, The at least two collimating lenses include a first collimating lens and a second collimating lens; The first collimating lens is located on the side of the second collimating lens closer to the light source; The focal length of the first collimating lens is 10-14mm, and the focal length of the second collimating lens is 18-22mm.

7. The photoresist particle counter according to claim 6, characterized in that, The first collimating lens is a plano-convex lens.

8. The photoresist particle counter according to claim 6, characterized in that, The second collimating lens is an aspherical lens.

9. The photoresist particle counter according to claim 1, characterized in that, The signal processing module includes a photodetector and a photodetector circuit; The photodetector is used to receive the optical signal passing through the fluid flow channel module and output the corresponding electrical signal; The photoelectric detection circuit is electrically connected to the photodetector. The photoelectric detection circuit is used to analyze and process the electrical signal to determine the number and size of particles flowing through the fluid channel module.

10. The photoresist particle counter according to claim 1, characterized in that, The fluid flow direction set in the fluid channel module is perpendicular to the propagation path of the parallel light beam.

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