Laser device, laser control method, and charged particle beam detection system

Abstract

The invention relates to a laser device, a laser control method and a charged particle beam detection system. The laser device comprises a controller, a multi-wavelength laser light source and a first dimming module. The controller is configured to match the working height of the working table and generate a wavelength selection instruction; wherein the working table is used for placing a semiconductor structure to be tested, and the working height of the working table is adjustable. The multi-wavelength laser light source is connected with the controller and is configured to respond to a wavelength selection instruction and emit a laser beam of a target wavelength. The first dimming module is located on the light emitting side of the multi-wavelength laser light source and is configured to adjust the transmission light path of the laser beam so that the laser beam can irradiate the semiconductor structure to be measured according to a first target angle. Wherein the laser beams with different target wavelengths correspondingly have different first target angles. The method and the device are used for assisting in charged particle detection so as to improve the comprehensiveness and the accuracy of semiconductor defect detection.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a laser device, a laser control method, and a charged particle beam detection system. Background Art

[0002] In the integrated circuit (IC) manufacturing process, optical microscopes are often used to inspect unfinished or completed microelectronic components to ensure they are manufactured according to design requirements and are defect-free. However, as the physical size of microelectronic components continues to decrease, higher-resolution inspection systems are required. Charged particle beam inspection systems, capable of providing nanometer-level resolution, have become a practical tool for inspecting microelectronic components with feature sizes less than 100 nanometers. Summary of the Invention

[0003] In a first aspect, some embodiments of the present application provide a laser device. The laser device includes a controller, a multi-wavelength laser light source, and a first dimming module. The controller is configured to match the working height of the work surface and generate a wavelength selection instruction; wherein the work surface is used to place the semiconductor structure to be tested, and the working height of the work surface is adjustable. The multi-wavelength laser light source is connected to the controller and is configured to respond to the wavelength selection instruction and emit a laser beam of a target wavelength. The first dimming module is located on the light-emitting side of the multi-wavelength laser light source and is configured to adjust the transmission optical path of the laser beam so that the laser beam is irradiated to the semiconductor structure to be tested at a first target angle. wherein laser beams of different target wavelengths correspond to different first target angles.

[0004] In some embodiments of the present application, a multi-wavelength laser light source includes: at least two laser generators connected to a controller; and a laser homogenization module corresponding to each laser generator and located on the light output side of each laser generator. Different laser generators are capable of emitting laser beams of different wavelengths. The laser generator emitting a laser beam with a wavelength equal to the target wavelength emits a laser beam in response to a wavelength selection instruction.

[0005] In some embodiments of the present application, the multi-wavelength laser light source further includes one or more beam splitter prisms; wherein each beam splitter prism is opposite to at least one laser homogenization module, and the light output side of one of the beam splitter prisms is opposite to the first dimming module.

[0006] In some embodiments of the present application, the first dimming module includes a laser refraction module.

[0007] In other embodiments of the present application, the first dimming module includes a laser refraction module and a laser reflection module sequentially arranged on the transmission optical path of the laser beam.

[0008] In some embodiments of the present application, the first dimming module further includes a laser shaping module disposed between the laser refraction module and the multi-wavelength laser light source.

[0009] In some embodiments of the present application, the laser device further includes a second dimming module. The second dimming module is located opposite the first dimming module and is configured to receive a reflected beam of the laser beam irradiated by the first dimming module onto the semiconductor structure under test, and adjust the transmission optical path of the reflected beam so that the reflected beam irradiates the semiconductor structure under test at a second target angle.

[0010] In some embodiments of the present application, the second dimming module includes: a first reflected light reflecting module, a reflected light refractive module, and a second reflected light reflecting module sequentially disposed on the transmission optical path of the reflected light beam.

[0011] In a second aspect, the present application also provides a laser control method according to some embodiments, which can be applied to the laser device described in any of the above embodiments. The laser control method includes: obtaining a working height of a work surface; the work surface is used to place the semiconductor structure to be measured, and the working height of the work surface is adjustable; generating a wavelength selection instruction based on the working height; emitting a laser beam of a target wavelength in response to the wavelength selection instruction; and adjusting the transmission optical path of the laser beam so that the laser beam is irradiated onto the semiconductor structure to be measured at a first target angle. The laser beams of different target wavelengths correspond to different first target angles.

[0012] In a third aspect, the present application also provides, according to some embodiments, a charged particle beam detection system, comprising a charged particle microscope and a laser device as described in any of the above embodiments. The laser device is located adjacent to the charged particle microscope and is configured to emit a laser beam toward a semiconductor structure to be tested, which is placed on a work surface; wherein the work surface has an adjustable working height.

[0013] In some embodiments of the present application, a laser device includes a first dimming module and a second dimming module disposed opposite the first dimming module. The first dimming module is located on a first side of a charged particle microscope, and the second dimming module is located on a second side of the charged particle microscope, with the second side and the first side facing each other in a direction parallel to a work surface.

[0014] The embodiments of the present application may or at least have the following advantages:

[0015] In an embodiment of the present application, a controller can control a multi-wavelength laser light source to emit a laser beam of a target wavelength, and a first dimming module can be used to adjust the transmission optical path of the laser beam. This allows different first target angles to be used for irradiation of semiconductor structures to be tested on work surfaces at different working heights, thereby optimizing the incident angle of the laser beam irradiating the semiconductor structure to be tested, so that the incident angle matches the different electron beam energies of the charged particle microscope to obtain better detection image quality and higher laser utilization efficiency. This embodiment of the present application has greater flexibility and wide applicability, and can adapt to various detection scenarios of the semiconductor structure to be tested, thereby assisting the charged particle microscope in achieving more comprehensive and accurate semiconductor defect detection.

[0016] The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 is a structural block diagram of a charged particle beam detection system provided in some embodiments;

[0019] Figure 2 is a schematic structural diagram of a charged particle beam detection system provided in some embodiments;

[0020] Figure 3 is a schematic structural diagram of another charged particle beam detection system provided in some embodiments;

[0021] Figure 4 is a schematic structural diagram of another charged particle beam detection system provided in some embodiments;

[0022] Figure 5 is a schematic structural diagram of a laser shaping module provided in some embodiments;

[0023] Figure 6 is a structural block diagram of another charged particle beam detection system provided in some embodiments;

[0024] Figure 7 is a schematic structural diagram of another charged particle beam detection system provided in some embodiments;

[0025] Figure 8A schematic diagram showing a comparison between an ideal cross section of a light spot and a measured cross section provided in some embodiments;

[0026] Figure 9 A phase quantization diagram of an 8-step phase-type diffractive optical element provided in some embodiments;

[0027] Figure 10 A light intensity distribution diagram of a target light spot provided in some embodiments;

[0028] Figure 11 A light intensity distribution diagram of an actual light spot provided in some embodiments;

[0029] Figure 12 for Figure 11 An enlarged schematic diagram of the light intensity distribution of the actual light spot is shown;

[0030] Figure 13 A schematic flow chart of a laser control method provided in some embodiments;

[0031] Figure 14 Schematic diagram of a flow chart of another laser control method provided in some embodiments.

[0032] Description of reference numerals:

[0033] 100- workbench, 200- semiconductor structure to be measured, 300- charged particle microscope, 400- laser device, 1- controller, 2- multi-wavelength laser light source, 21A- first laser generator, 21B- second laser generator, 21C- third laser generator, 22A- first laser homogenization module, 22B- second laser homogenization module, 22C- third laser homogenization module, 23- beam splitter prism, 23A- first beam splitter prism, 23B- second beam splitter prism, 3-first dimming module, 31-laser refraction module, 32-laser reflection module, 32A-first reflector, 32B-second reflector, 33-laser shaping module, 331-concave lens, 332-doublet lens, 4-second dimming module, 41-first reflected light reflection module, 42-reflected light refraction module, 43-second reflected light reflection module, 310-electron gun, 320-condenser, 330-aperture, 340-deflection coil, 350-objective lens. DETAILED DESCRIPTION

[0034] To facilitate understanding of the present application, a more comprehensive description of the present application will be provided below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0036] It should be understood that when an element or layer is referred to as being "on," "adjacent to," or "connected to" another element or layer, it may be directly on, adjacent to, connected to, or coupled to the other element or layer, or there may be intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, doping types, and / or portions, these elements, components, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, doping type, or portion from another element, component, region, layer, doping type, or portion. Thus, a first element, component, region, layer, doping type, or portion discussed below may be represented as a second element, component, region, layer, or portion without departing from the teachings of the present application.

[0037] As used herein, the singular forms "a," "an," and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that when the terms "comprising" and / or "including" are used in this specification, they may specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. At the same time, when used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0038] See also Figure 1 The present invention provides a charged particle beam detection system for detecting a semiconductor structure 200 placed on a work surface of a workbench 100. The charged particle beam detection system includes a charged particle microscope 300 and a laser device 400 disposed adjacent to the charged particle microscope 300. The laser device 400 can emit a laser beam to illuminate the semiconductor structure 200 to assist in defect detection of the semiconductor structure 200.

[0039] For example, the charged particle microscope 300 includes but is not limited to a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

[0040] By way of example, the semiconductor structure 200 to be tested includes, but is not limited to, a wafer.

[0041] In some examples, the charged particle microscope 300 is a scanning electron microscope and the semiconductor structure 200 to be tested is a wafer. Figure 2 The scanning electron microscope, for example, includes an electron gun 310, a condenser 320, an aperture 330, a deflection coil 340, and an objective lens 350, arranged in sequence along the direction of electron beam emission. The scanning electron microscope can focus electrons from one or more primary electron beams at a predetermined scanning position on the wafer, allowing the electrons to interact with the wafer, thereby characterizing whether the wafer has defects based on the internal and / or external structural characteristics of the wafer. Thus, during the process of inspecting the wafer using the scanning electron microscope, the laser device 400 can be used to illuminate the wafer with a laser beam, thereby activating the wafer and optimizing the wafer defect detection effect.

[0042] Please continue reading Figure 1 Some embodiments of the present application provide a laser device 400. The laser device 400 includes a controller 1, a multi-wavelength laser light source 2 and a first dimming module 3. The controller 1 is configured to match the working height of the work table and generate a wavelength selection instruction; wherein the work table is used to place the semiconductor structure 200 to be tested, and the working height of the work table is adjustable. The multi-wavelength laser light source 2 is connected to the controller 1 and is configured to respond to the wavelength selection instruction and emit a laser beam of a target wavelength. The first dimming module 3 is located on the light-emitting side of the multi-wavelength laser light source 2 and is configured to adjust the transmission optical path of the laser beam so that the laser beam is irradiated to the semiconductor structure 200 to be tested at a first target angle. Wherein, laser beams of different target wavelengths correspond to different first target angles.

[0043] It can be understood that the working height of the work table is adjustable, which means that in different detection scenarios, the distance between the work table and the charged particle microscope 300 can be set at different working heights to match the needs. In the embodiment of the present application, the wavelength selection instruction is generated to match the working height of the work table. The controller 1 can control the multi-wavelength laser light source 2 to correspond to different working heights to reasonably select the laser beam of the target wavelength to be emitted, and ensure that the laser beam can be irradiated to the semiconductor structure 200 to be tested according to the first target angle through the first dimming module 3. In other words, the laser device 400 provided in the embodiment of the present application can match the use of laser beams of different target wavelengths to irradiate the semiconductor structure 200 to be tested according to different table heights of the work table, and effectively optimize the incident angle of the laser beam on the semiconductor structure 200 to be tested, thereby improving the imaging quality of the charged particle beam detection system.

[0044] For example, Figure 2As shown, the workbench has two working heights, wherein, for the first working height H1, the controller 1 can control the multi-wavelength laser light source 2 to use a laser beam with a first wavelength λ1 for irradiation, and the first wavelength λ1 can be, for example, 532nm, but is not limited to this; for the second working height H2, the controller 1 can control the multi-wavelength laser light source 2 to use a laser beam with a second wavelength λ2 for irradiation, and the second wavelength λ2 can be, for example, 650nm, but is not limited to this.

[0045] In the embodiment of the present application, the controller 1 can control the multi-wavelength laser light source 2 to emit a laser beam of a target wavelength, and the first dimming module 3 can adjust the transmission optical path of the laser beam. This allows different first target angles to be used for irradiation of the semiconductor structure 200 to be tested on work surfaces at different working heights, thereby optimizing the incident angle of the laser beam irradiating the semiconductor structure 200 to be tested, so that the incident angle matches the different electron beam energies of the charged particle microscope 300 to obtain better detection image quality and higher laser utilization efficiency. The embodiment of the present application has greater flexibility and wide applicability, and can adapt to various detection scenarios of the semiconductor structure 200 to be tested, thereby assisting the charged particle microscope 300 in achieving more comprehensive and accurate semiconductor defect detection.

[0046] In some embodiments of this application, please combine Figures 1 to 3 It is understood that the multi-wavelength laser light source 2 includes: at least two laser generators (eg Figure 2 The first laser generator 21A and the second laser generator 21B shown in FIG. Figure 3 The first laser generator 21A, the second laser generator 21B and the third laser generator 21C shown in FIG, and the laser homogenization module (eg Figure 2 The first laser homogenizing module 22A and the second laser homogenizing module 22B shown in FIG. Figure 3 , a first laser homogenization module 22A, a second laser homogenization module 22B, and a third laser homogenization module 22C are shown in FIG. Different laser generators are capable of emitting laser beams of different wavelengths. For example, the first laser generator 21A is configured to emit a laser beam having a first wavelength λ1 to match a first working height H1 of the work surface; the second laser generator 21B is configured to emit a laser beam having a second wavelength λ2 to match a second working height H2 of the work surface; and the third laser generator 21C is configured to emit a laser beam having a third wavelength λ3 to match a third working height H3 of the work surface. Furthermore, among the laser generators, the laser generator emitting a laser beam having a wavelength equal to the target wavelength will emit a laser beam in response to the wavelength selection instruction.

[0047] It can be understood that the embodiment of the present application does not limit the number of laser generators in the multi-wavelength laser light source 2, that is, a larger number of laser generators can be set in the multi-wavelength laser light source 2 to ensure that there is a wider range of laser beam wavelength selection, thereby meeting various detection scenarios.

[0048] In the embodiments of the present application, a laser homogenization module is provided in a one-to-one correspondence with a laser generator, and is used to homogenize the Gaussian energy distribution of the laser beam emitted by the laser generator into a flat top beam. The laser homogenization module includes, but is not limited to, at least one of a diffractive optical element, a shaping lens, or a microlens array.

[0049] In some embodiments of this application, please continue to refer to Figures 1 to 3 The multi-wavelength laser light source 2 further includes one or more beam splitter prisms; each beam splitter prism is opposite at least one laser homogenization module, and the light-emitting side of one beam splitter prism is opposite the first dimming module 3. The beam splitter prisms can be positioned to adjust the transmission percentage, reflection percentage, and polarization state of the laser beam as needed, and are not specifically limited in this embodiment of the present application.

[0050] In some examples, such as Figure 2 As shown in FIG, the multi-wavelength laser light source 2 includes a beam splitter prism 23. The beam splitter prism 23 has two light incident surfaces, which are respectively disposed opposite the first laser homogenization module 22A and the second laser homogenization module 22B. It also has a light emitting surface, which is disposed opposite the first dimming module 3, to emit a laser beam of the target wavelength to the first dimming module 3.

[0051] In other examples, such as Figure 3 As shown in , the multi-wavelength laser light source 2 includes two beam splitter prisms (e.g., a first beam splitter prism 23A and a second beam splitter prism 23B). The first beam splitter prism 23A has two light incident surfaces, which are respectively disposed opposite the light exit surfaces of the first laser homogenization module 22A and the second beam splitter prism 23B. It also has a light exit surface, which is disposed opposite the first dimming module 3. The second beam splitter prism 23B has two light incident surfaces, which are respectively disposed opposite the second laser homogenization module 22B and the third laser homogenization module 22C. It also has a light exit surface, which is disposed opposite the light incident surface of the first beam splitter prism 23A. Among them, according to the emission direction of the laser beam, the laser beam of the first wavelength λ1 emitted by the first laser generator 21A can be emitted to the first dimming module 3 through the first beam splitter prism 23A; the laser beam of the second wavelength λ2 emitted by the second laser generator 21B can be emitted to the first dimming module 3 through the second beam splitter prism 23B and the first beam splitter prism 23A in sequence; the laser beam of the third wavelength λ3 emitted by the third laser generator 21C can be emitted to the first dimming module 3 through the second beam splitter prism 23B and the first beam splitter prism 23A in sequence.

[0052] By analogy, by adding a beam splitter prism to the multi-wavelength laser light source 2, the embodiment of the present application can be expanded to include more laser generators with different wavelengths to accommodate a wider range of working heights on the work surface, thereby being able to adapt to a wider range of detection scenarios for the semiconductor structure 200 to be tested. The embodiment of the present application has better scalability and adaptability.

[0053] It should be noted that in some embodiments of this application, please combine Figures 1 to 4 It is understood that the first dimming module 3 is used to adjust the transmission optical path of the laser beam. The first dimming module 3 can be composed of one or more optical devices to ensure that the laser beam is irradiated to the semiconductor structure 200 to be tested according to the first target angle.

[0054] In some examples, the first dimming module 3 includes a laser refraction module 31 .

[0055] For example, the laser refraction module 31 includes one or more sequentially arranged wedge prisms. The wedge prisms are, for example, glass prisms. The wedge prisms have different refractive indices for laser beams of different wavelengths. This allows laser beams of different wavelengths to be emitted at different target angles after being refracted by the wedge prisms, thereby ensuring that the laser beams are irradiated at the target angle onto the semiconductor structure 200 under test at the corresponding working height.

[0056] Furthermore, the dispersion coefficient of the aforementioned wedge prism can be determined by matching the wavelength of the laser beam emitted by the laser generator and the working height of the work surface, and the wedge prism can be manufactured using a suitable wedge glass material. Furthermore, by adjusting the wedge prism's material and / or bevel angle, the laser beam can be more accurately directed toward the semiconductor structure 200 under test, further improving laser utilization efficiency and imaging quality.

[0057] In some other examples, the first dimming module 3 includes a laser refraction module 31 and a laser reflection module 32 sequentially disposed on the transmission optical path of the laser beam.

[0058] For example, the laser refraction module 31 includes one or more sequentially arranged wedge prisms; and / or the laser reflection module 32 includes one or more sequentially arranged reflection mirrors.

[0059] For example, Figure 4 As shown in FIG, the laser reflection module 32 includes a first reflection mirror 32A and a second reflection mirror 32B sequentially arranged on the transmission optical path of the laser beam. Optionally, the second reflection mirror 32B includes but is not limited to a plane reflection mirror parallel to the work surface.

[0060] As described above, in the embodiments of the present application, by increasing the number of reflectors within the laser reflection module 32, the transmission distance of the laser beam can be correspondingly increased, thereby increasing the adjustable range of the work surface relative to the working height. Furthermore, by selectively utilizing one or more optical elements and their corresponding optical paths within the laser refraction module 31 and the laser reflection module 32, the embodiments of the present application can optimize the transmission optical path of the laser beam, thereby further improving the quality of the detection imaging.

[0061] In some embodiments of this application, please continue to refer to Figures 1 to 4 The first dimming module 3 further includes a laser shaping module 33 disposed between the laser refraction module 31 and the multi-wavelength laser light source 2. The laser shaping module 33 is used to shape the laser beam into various energy distributions tailored to specific treatments and processes. For example, the laser beam can be converted into a circular, rectangular, square, straight, or other custom-shaped spot, thereby improving the power utilization of the laser beam and the laser control effect.

[0062] For example, the laser shaping module 33 includes but is not limited to a prism combination, a cylindrical lens combination, or a microlens array.

[0063] In some examples, the first laser generator 21A is configured to emit a first laser beam having a first wavelength λ1 of 450 nm, and the second laser generator 21B is configured to emit a second laser beam having a first wavelength λ2 of 520 nm. The difference between the first working height H1 and the second working height H2 of the work surface relative to the reference plane can range from 1 mm to 3 mm, and the first target angles corresponding to the first and second laser beams can range from 10° to 30°.

[0064] Optionally, the collimated laser spot diameter is 0.5 mm, the bevel angle of the wedge prism in the laser refraction module 31 can range from 1° to 3°, the refractive index of the wedge prism can range from 1.5 to 1.8, and the Abbe number of the wedge prism can range from 40 to 70.

[0065] Optionally, see Figure 5The laser shaping module 33 is a lens combination consisting of a concave lens 331 and a doublet lens 332, which can achieve a 2x beam expansion of the laser beam within the visible light wavelength range. The radius of curvature of the first surface of the concave lens 331 is, for example, -1.628 mm, and the radius of curvature of the second surface is, for example, -3.271 mm. The thickness of the concave lens 331 is, for example, 0.5 mm. The refractive index of the concave lens 331 is, for example, 1.51. The Abbe number of the concave lens 331 is, for example, 64.2. The radius of curvature of the first surface of the doublet lens 332 is, for example, -9.193 mm, the radius of curvature of the second surface is, for example, -2.813 mm, and the radius of curvature of the third surface is, for example, -3.885 mm. The thickness of the doublet lens 332 is, for example, 1 mm. The refractive index of the first lens of the doublet lens 332 is, for example, 1.51, and the Abbe number is, for example, 64.2. The refractive index of the second lens in the doublet lens 332 is, for example, 1.65, and the Abbe number is, for example, 33.8.

[0066] In some embodiments of this application, please refer to Figure 6 The laser device 400 further includes a second dimming module 4. The second dimming module 4 is located on the opposite side of the first dimming module 3 and is configured to receive a reflected beam of the laser beam irradiated by the first dimming module 3 onto the semiconductor structure 200 under test, and adjust the transmission optical path of the reflected beam so that the reflected beam irradiates the semiconductor structure 200 under test at a second target angle.

[0067] For example, please see Figure 6 The first dimming module 3 is located on a first side of the charged particle microscope 300 , and the second dimming module 4 is located on a second side of the charged particle microscope 300 , and the second side and the first side are opposite to each other in a direction parallel to the work surface.

[0068] For example, see Figure 7 The second dimming module 4 includes a first reflected light reflecting module 41 , a reflected light refraction module 42 and a second reflected light reflecting module 43 which are sequentially arranged on the transmission optical path of the reflected light beam.

[0069] Optionally, the first reflected light reflecting module 41 and the second reflected light reflecting module 43 both include but are not limited to one or more reflectors. The second reflected light reflecting module 43 can be, for example, a plane reflector parallel to the work surface.

[0070] Optionally, the reflective light refraction module 42 includes but is not limited to one or more wedge prisms. The selection of the wedge prisms in the reflective light refraction module 42 can be made with reference to the selection of the wedge prisms in the laser refraction module 31 .

[0071] Optionally, the first dimming module 3 includes a laser refraction module 31 and a laser reflection module 32 sequentially arranged on the laser beam transmission optical path. The first reflected light reflection module 41 in the second dimming module 4 and the laser reflection module 32 in the first dimming module 3 are symmetrically arranged with the charged particle microscope 300 as the center. The reflected light refraction module 42 in the second dimming module 4 and the laser refraction module 31 in the first dimming module 3 are symmetrically arranged with the charged particle microscope 300 as the center.

[0072] In the embodiment of the present application, by setting a second dimming module 4 on the opposite side of the first dimming module 3, that is, setting dimming modules on the first side and the second side of the charged particle microscope 300 respectively, the reflected light beam of the laser beam irradiated on the semiconductor structure 200 to be tested can also be recycled by the second dimming module 4, thereby optimizing the optical path design of the laser device to maximize the laser utilization efficiency and detection imaging quality of the laser beam, thereby improving the detection efficiency and detection accuracy of the charged particle beam detection system.

[0073] It is worth mentioning that, in some examples, the laser homogenization module uses a diffraction optical element, which can avoid uneven energy of the laser beam spot, that is, it can produce a light spot with high uniformity.

[0074] For example, please combine Figure 8 understand, Figure 8 A schematic diagram comparing an ideal cross-section of a light spot and a measured cross-section is shown. The laser device 400 is located on one side of the charged particle microscope 300 along the X direction. The laser beam emitted by the laser device 400 is incident at an angle to the semiconductor structure 200 to be measured. Therefore, the laser beam spot needs to be compressed along the Y direction to be reshaped into an elliptical light spot, where the Y direction is perpendicular to the X direction.

[0075] Correspondingly, the diffractive optical element adopts an 8-step phase-type diffractive optical element, which can effectively realize the uniform light shaping conversion from a Gaussian beam to an elliptical flat-top beam.

[0076] Optionally, the phase of the 8-step phase-type diffractive optical element is designed and obtained based on a Gerchberg-Saxton (GS) iterative algorithm, for example, it can be determined according to the following iterative calculation steps S10 to S50.

[0077] S10, initializing the random phase of the diffractive optical element.

[0078] S20, forwardly propagating the laser beam to the target surface based on the diffractive optical element.

[0079] S30, replacing the output amplitude of the laser beam with the amplitude of the target surface, and then propagating it back to the diffraction surface of the diffractive optical element.

[0080] S40, quantizing the phase of the diffractive optical element to an 8-step phase, completing one phase iteration.

[0081] S50, judging whether the number of iterations meets the preset number; if so, outputting the current 8-step phase as the final phase of the diffractive optical element; if not, returning to executing steps S20 to S60 until the number of iterations meets the preset number.

[0082] Figure 9 A phase quantization diagram of an 8-step phase-type diffractive optical element is exemplarily provided.

[0083] In addition, in order to quantitatively evaluate the uniformity of the light beam after the diffractive optical element is used to shape the light, in the embodiment of the present application, a laser device is simulated by taking the diffractive optical element as an example of an 8-step phase diffractive optical element (the phase of the 8-step phase diffractive optical element is, for example, Figure 9 ), and the statistical characteristics of the light intensity distribution and the uniformity coefficient U within the target elliptical area were obtained. Where U = 1-σ / μ, μ is the average light intensity within the target area, and σ is the standard deviation of the light intensity.

[0084] Please combine Figures 10 to 12 Understand, the corresponding simulation results are as follows:

[0085] - Average light intensity μ = 0.038 (au);

[0086] - Standard deviation σ = 0.008 (au);

[0087] - Uniformity coefficient U=78.95%;

[0088] - Minimum / maximum light intensity ratio = 61.23%.

[0089] According to the above simulation results, it can be seen that the light intensity uniformity in the target area has reached a high level (uniformity coefficient>78%), which can meet the needs of application scenarios.

[0090] In addition, the embodiment of the present application also quantitatively measures some key performance indicators of the aforementioned laser device, as shown in Table 1.

[0091]

[0092] Table 1

[0093] The present application also provides a laser control method for use with the laser device described in any of the above embodiments. The laser control method also possesses the technical advantages of the aforementioned laser device, which will not be elaborated here.

[0094] See also Figure 13, the laser control method includes the following steps S100~S400.

[0095] S100: Acquire a working height of a work surface, where the work surface is used to place a semiconductor structure to be tested, and the working height of the work surface is adjustable.

[0096] S200: Generate a wavelength selection instruction according to the working height.

[0097] S300, responding to the wavelength selection instruction, emitting a laser beam of a target wavelength.

[0098] S400: Adjusting the transmission optical path of the laser beam so that the laser beam irradiates the semiconductor structure to be measured at a first target angle, wherein laser beams of different target wavelengths have correspondingly different first target angles.

[0099] Here, the adjustment of the laser beam transmission optical path can be achieved by referring to the relevant description of the first dimming module in some of the aforementioned embodiments.

[0100] In some embodiments of this application, please refer to Figure 14 , the laser control method further includes steps S500 and S600.

[0101] S500 , receiving a reflected light beam of a laser beam irradiated onto a semiconductor structure to be tested.

[0102] S600 , adjusting the transmission optical path of the reflected light beam so that the reflected light beam irradiates the semiconductor structure to be measured at a second target angle.

[0103] Here, the adjustment of the transmission path of the reflected light beam can be achieved by referring to the relevant description of the second dimming module in some of the aforementioned embodiments.

[0104] It should be noted that the laser device and laser control method provided by the embodiments of the present application, in addition to being applied in the field of charged particle beam detection, can also be widely applied in the fields of laser technology and power electronics. For example, in the field of laser technology, the embodiments of the present application can be used as a laser source capable of matching different working heights to provide laser beams of different wavelengths for processing or detection. In the field of power electronics, the embodiments of the present application can be used as a laser source capable of matching different working heights to provide laser beams of different wavelengths for detection or repair of unfinished or completed circuit components, thereby ensuring the improvement of the quality and reliability of power electronics.

[0105] In the description of this specification, reference to the terms "some embodiments," "some examples," "exemplarily," etc., means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0106] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0107] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the scope of the present application, and such modifications and improvements are all within the scope of protection of the present application.

Claims

1. A laser device, characterized in that: include: A controller configured to: match the working height of a work surface and generate a wavelength selection instruction; the work surface is used to place a semiconductor structure to be measured; the working height of the work surface is adjustable; a multi-wavelength laser light source connected to the controller and configured to: emit a laser beam of a target wavelength in response to the wavelength selection instruction; a first dimming module, located at the light-emitting side of the multi-wavelength laser light source, configured to: adjust the transmission optical path of the laser beam so that the laser beam irradiates the semiconductor structure to be measured at a first target angle; The laser beams with different target wavelengths have correspondingly different first target angles.

2. The laser device according to claim 1, characterized in that The multi-wavelength laser light source includes: at least two laser generators connected to the controller, and a laser homogenization module corresponding to the laser generators and located at the light output side of the corresponding laser generators; Wherein, different laser generators can emit laser beams of different wavelengths; the laser generator whose output laser beam wavelength is equal to the target wavelength emits the laser beam in response to the wavelength selection instruction.

3. The laser device according to claim 2, characterized in that The multi-wavelength laser light source further includes one or more beam splitter prisms; wherein each of the beam splitter prisms is opposite to at least one of the laser homogenization modules, and the light emitting side of one of the beam splitter prisms is opposite to the first dimming module.

4. The laser device according to claim 1, wherein The first dimming module includes a laser refraction module; Alternatively, the first dimming module includes a laser refraction module and a laser reflection module sequentially arranged on the transmission optical path of the laser beam.

5. The laser device according to claim 4, characterized in that The first dimming module further includes a laser shaping module disposed between the laser refraction module and the multi-wavelength laser light source.

6. The laser device according to any one of claims 1 to 5, characterized in that Also includes: The second dimming module is located on the opposite side of the first dimming module and is configured to: receive the reflected light beam of the laser beam irradiated by the first dimming module to the semiconductor structure to be tested, and adjust the transmission light path of the reflected light beam so that the reflected light beam is irradiated to the semiconductor structure to be tested at a second target angle.

7. The laser device according to claim 6, characterized in that The second dimming module includes a first reflected light reflecting module, a reflected light refraction module, and a second reflected light reflecting module which are sequentially arranged on the transmission optical path of the reflected light beam.

8. A laser control method, characterized in that: Applicable to the laser device according to any one of claims 1 to 7; the laser control method comprises: Obtaining a working height of a work surface; the work surface is used to place a semiconductor structure to be tested, and the working height of the work surface is adjustable; generating a wavelength selection instruction according to the working height; In response to the wavelength selection instruction, emitting a laser beam of a target wavelength; Adjusting the transmission optical path of the laser beam so that the laser beam irradiates the semiconductor structure to be measured at a first target angle; The laser beams with different target wavelengths have correspondingly different first target angles.

9. A charged particle beam detection system, characterized in that: include: charged particle microscopy; The laser device according to any one of claims 1 to 7, located next to the charged particle microscope, is configured to emit a laser beam to a semiconductor structure to be measured placed on a work surface; wherein the working height of the work surface is adjustable.

10. The charged particle beam detection system according to claim 9, wherein: The laser device includes the first dimming module and a second dimming module arranged on the opposite side of the first dimming module; The first dimming module is located on a first side of the charged particle microscope, the second dimming module is located on a second side of the charged particle microscope, and the second side and the first side are opposite to each other in a direction parallel to the workbench.

Images