Electron beam detection equipment and auxiliary irradiation device thereof

Abstract

The utility model discloses an auxiliary irradiation device for electron beam detection equipment and the electron beam detection equipment. The auxiliary irradiation device comprises a light source, an optical assembly and a photoelectric detector. The optical assembly is used for receiving incident light emitted by the light source and guiding the incident light to be focused on the surface of the element to be detected at least twice; the optical assembly comprises a first optical element group and a second optical element group; the first optical element group is used for receiving incident light and forming a first focused light beam emitted to the surface of a to-be-detected element, and the first focused light beam is focused on a first focus on the surface of the to-be-detected element and can be reflected by the surface of the to-be-detected element to form a first reflected light beam; the second optical element group is used for receiving the first reflected light beam and forming a second focused light beam emitted to the surface of the to-be-detected element, and the second focused light beam is focused on a second focus on the surface of the to-be-detected element; the light spot at the first focal point coincides with the light spot at the second focal point; the photoelectric detector is used for detecting image information and / or light intensity information of the light spots.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor, and particularly relates to an auxiliary irradiation device for an electron beam detection device and the electron beam detection device. BACKGROUND

[0002] In recent years, semiconductor-related equipment has developed rapidly, and an electron beam detection device is a key device for detecting the performance and defects of a semiconductor device in a semiconductor manufacturing process and is an important guarantee for chip yield.

[0003] In detection, in order to improve the substrate brightness of an image, using a laser to irradiate a component to be detected is a common technical means for improving detection efficiency. The laser can excite the energy level state of the surface material of the semiconductor device, improve the electron efficiency during detection, so that the detector can capture more electrons and obtain more clear detection information. However, for detection requirements with higher and higher precision and higher and higher efficiency, the existing technology is difficult to meet, which has become a restricting factor for the development of detection technology. CONTENT OF THE INVENTION

[0004] The embodiment of the present application provides an auxiliary irradiation device for an electron beam detection device and the electron beam detection device, which is beneficial to improve detection precision and detection efficiency, reduce power requirements for a light source, and reduce costs.

[0005] According to a first aspect of the present application, the present application provides an auxiliary irradiation device for an electron beam detection device, which comprises a light source, an optical assembly, and a photodetector. The light source is used to emit incident light. The optical assembly is used to receive the incident light and guide the incident light to focus on the surface of a detection element at least twice. The optical assembly comprises a first optical element group and a second optical element group. The first optical element group is used to receive the incident light and form a first focused light beam directed to the surface of the detection element. The first focused light beam focuses on a first focal point on the surface of the detection element and can be reflected by the surface of the detection element to form a first reflected light beam. The second optical element group is used to receive the first reflected light beam and form a second focused light beam directed to the surface of the detection element. The second focused light beam focuses on a second focal point on the surface of the detection element. The light spot at the first focal point and the light spot at the second focal point coincide. The photodetector is used to detect image information and / or light intensity information of the light spot.

[0006] In some embodiments, the second focused light beam is reflected by the surface of the detection element to form a second reflected light beam directed to the first optical element group. The first optical element group is configured to guide the second reflected light beam to the photodetector.

[0007] In some embodiments, the first optical element group comprises a light path selection component and a first focusing element, and the light path selection component and the first focusing element are optically connected; the light path selection component is configured to transmit the incident light emitted by the light source to the first focusing element, and is further configured to reflect the second reflected light beam emitted from the first focusing element to the photodetector; and the first focusing element is configured to form the first focused light beam.

[0008] In some embodiments, the light path selection component comprises a polarization component and a quarter-wave plate, and the quarter-wave plate is arranged between the polarization component and the first focusing element along the propagation direction of the incident light; the polarization direction of the polarization component is consistent with the polarization direction of the incident light emitted by the light source; the polarization component is configured to adjust the incident light emitted by the light source into incident linearly polarized light and transmit the incident linearly polarized light to the quarter-wave plate; the quarter-wave plate is configured to adjust the incident linearly polarized light into incident circularly polarized light and transmit the incident circularly polarized light to the first focusing element, and is further configured to adjust the reflected circularly polarized light emitted from the first focusing element into reflected linearly polarized light and transmit the reflected linearly polarized light to the polarization component, wherein the polarization direction of the reflected linearly polarized light is perpendicular to the polarization direction of the polarization component; and the polarization component is configured to reflect the reflected linearly polarized light to the photodetector.

[0009] In some embodiments, the first optical element group comprises a first focusing element configured to form the first focused light beam, and the second optical element group comprises a second focusing element configured to form the second focused light beam; the optical axis of the first focusing element forms a first included angle with the surface of the to-be-detected element, and the optical axis of the second focusing element forms a second included angle with the surface of the to-be-detected element, wherein the first included angle is equal to the second included angle, and both are less than 90°.

[0010] In some embodiments, the first focusing element and the second focusing element are both focusing lenses.

[0011] In some embodiments, the second optical element group comprises a second focusing element and a light ray folding device; the second focusing element is configured to transmit the first reflected light beam to the light ray folding device, and the light ray folding device is configured to fold the first reflected light beam emitted from the second focusing element to the second focusing element, and the second focusing element is further configured to form the second focused light beam.

[0012] In some embodiments, the light ray folding device is configured to fold the first reflected light beam emitted from the second focusing element to the second focusing element in parallel and opposite directions.

[0013] In some embodiments, the light ray folding device comprises a corner cube prism.

[0014] In some embodiments, the auxiliary irradiation device further comprises a first driving controller connected to the light source, configured to stimulate the light source to emit incident light; and a second driving controller connected to the photodetector and the first driving controller, configured to acquire image information and / or light intensity information detected by the photodetector, and send a control signal to the first driving controller according to the image information and / or the light intensity information, so that the first driving controller adjusts the emission power of the light source according to the control signal.

[0015] According to a second aspect of the present application, the present application further provides an electron beam detection device, comprising: an electron beam source configured to emit an incident electron beam to a to-be-detected element, the incident electron beam forming a detection focus on a surface of the to-be-detected element; an electron detector configured to detect outgoing electrons formed after the incident electron beam irradiates the surface of the to-be-detected element; and the auxiliary irradiation device according to any one of the embodiments of the first aspect of the present application, the detection focus being located in the light spot.

[0016] The auxiliary irradiation device provided by the embodiments of the present application is provided with an optical assembly, which guides the incident light emitted by the light source to be focused on the surface of the to-be-detected element at least twice, and the light spots at the focus points formed on the surface of the to-be-detected element coincide, so that more photon energy can be absorbed by the electrons on the surface of the to-be-detected element to generate greater energy level transition, which is conducive to obtaining more number of electrons during detection, obtaining more surface information of the to-be-detected element and higher detection efficiency. The embodiments of the present application improve the light intensity of the light spot by the way of multiple focusing, which is conducive to improving the detection accuracy and detection efficiency, and reducing the power requirement of the light source, reducing the volume and weight of the light source, which is conducive to integrating the light source into the electron beam detection device and reducing the cost.

[0017] The photodetector can acquire image information and / or light intensity information of the light spot, and can monitor whether the shape, size and the like of the light spot meet the requirements, whether the light power density of the light spot has large fluctuations and the like, which is conducive to timely adjusting the position of the light spot or compensating the incident light to improve the reliability and stability of the detection device. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating any creative labor on the basis of these drawings.

[0019] Figure 1 The auxiliary irradiation device and the structure diagram of the first part of the light path provided by some embodiments of the present application are shown in the structure diagram.

[0020] Figure 2A structure diagram of an auxiliary irradiation device and a second part of an optical path thereof according to some embodiments of the present application;

[0021] Figure 3 A structure diagram of an electron beam detection device according to some embodiments of the present application.

[0022] In the drawings:

[0023] Auxiliary irradiation device 1, light source 10, optical assembly 20, first optical element group 21, light path selection assembly 211, polarization component 2111, one-fourth wave plate 2112, first focusing element 212, second optical element group 22, second focusing element 221, light ray folding device 222, photodetector 30, first drive controller 40, second drive controller 50, electron beam a, first focal point A1, second focal point A2, detection focal point D, first reflected light beam F1, second reflected light beam F2, first focused light beam P1, second focused light beam P2;

[0024] Detection element 2;

[0025] Electron beam detection device 3, electron beam source 4, electronic detector 5. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0027] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms “include” and “have” and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover not exclusive inclusion. The terms “first”, “second” and the like in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, rather than to describe a particular order or primary and secondary relationship.

[0028] In the present application, the phrase “embodiment” means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments.

[0029] In the description of the present application, it should be noted that unless specifically defined and limited, the terms "mounting", "connected", "connection", "attached" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0030] In the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0031] In the embodiments of the present application, the same reference signs represent the same parts, and for the sake of brevity, the detailed description of the same parts is omitted in different embodiments. It should be understood that the thickness, length and width of various components in the embodiments of the present application shown in the drawings, and the overall thickness, length and width of the integrated device are only exemplary and should not constitute any limitation on the present application.

[0032] In the present application, "multiple" refers to more than two (including two).

[0033] In the embodiments of the present application, "parallel" not only includes the case of absolute parallel, but also includes the case of approximately parallel which is generally recognized in engineering; at the same time, "perpendicular" not only includes the case of absolute perpendicular, but also includes the case of approximately perpendicular which is generally recognized in engineering.

[0034] The applicant realizes that the factors restricting the development of detection technology mainly include cost, volume and weight, beam quality, stability, etc. High-power laser light sources are high in cost and difficult to integrate into detection equipment, while small and medium-power laser light sources are difficult to meet the requirements of high efficiency and high precision detection.

[0035] In view of this, the embodiments of the present application provide a technical solution, which sets an optical assembly, uses the optical assembly to guide the incident light emitted by the light source, so that the incident light is focused on the surface of the detected element at least twice, and the light spots at the focal points formed on the surface of the detected element at least partially overlap. By the way of multiple focusing, the light power density of the light spot is superimposed, which is conducive to improving the detection accuracy and detection efficiency, reducing the power requirement of the light source, reducing the volume and weight of the light source, etc., which is conducive to the integration of the light source in the detection equipment and reduces the cost.

[0036] The auxiliary illumination device and the electron beam detection equipment of the present application will be described below with reference to the accompanying drawings.

[0037] Figure 1 A structure diagram of a first part of a light path of an auxiliary irradiation device provided for some embodiments of the present application, Figure 2 A structure diagram of a second part of a light path of an auxiliary irradiation device provided for some embodiments of the present application, Figure 3 A structure diagram of an electron beam detection device provided for some embodiments of the present application.

[0038] With reference to Figures 1 to 3 The present application provides an auxiliary irradiation device 1. The auxiliary irradiation device 1 provided by the present application can be applied to an electron beam detection device 3, which is particularly used for detecting a wafer.

[0039] With reference to Figure 1 and Figure 2 The auxiliary irradiation device 1 provided by the present application includes a light source 10, an optical assembly 20, and a photodetector 30.

[0040] The light source 10 is used for emitting incident light.

[0041] The optical assembly 20 is used for receiving the incident light emitted by the light source 10 and guiding the incident light emitted by the light source 10 to focus on the surface of a to-be-detected element (for example, a wafer) at least twice. The optical assembly 20 includes a first optical element group 21 and a second optical element group 22. The first optical element group 21 is used for receiving the incident light and forming a first focused light beam P1 directed to the surface of the to-be-detected element 2, the first focused light beam P1 focuses on a first focal point A1 on the surface of the to-be-detected element 2, and can be reflected by the surface of the to-be-detected element 2 to form a first reflected light beam F1. The second optical element group 22 is used for receiving the first reflected light beam F1 and forming a second focused light beam P2 directed to the surface of the to-be-detected element 2, the second focused light beam P2 focuses on a second focal point A2 on the surface of the to-be-detected element 2. The light spot at the first focal point A1 and the light spot at the second focal point A2 coincide.

[0042] The photodetector 30 is used for detecting image information and / or light intensity information of the light spot.

[0043] The incident light emitted by the light source 10 can excite the energy level state of the substance on the surface of the to-be-detected element, so that the electrons on the surface of the to-be-detected element absorb photon energy and produce energy level transition.

[0044] Optionally, the light source 10 can be a laser light source, and the incident light emitted by the light source 10 can be laser light.

[0045] The light source 10 can be arranged outside a sample chamber of the electron beam detection device, and the optical assembly 20 and the photodetector 30 can be arranged inside the sample chamber of the electron beam detection device. The incident light emitted by the light source 10 can be introduced into the sample chamber through an optical fiber, a hard light path, or the like, and irradiated to the optical assembly 20.

[0046] The first optical element group 21 and the second optical element group 22 can each include a plurality of optical elements, which are sequentially connected in the propagation direction of the incident light. The plurality of optical elements can collimate, polarize, transmit, reflect, and / or refract the incident light, and propagate the incident light.

[0047] The light source 10 is optically connected to the first optical element group 21, and the first optical element group 21 is optically connected to the second optical element group 22. The first optical element group 21 and the second optical element group 22 are both arranged downstream of the light path of the light source 10.

[0048] The first optical element group 21 is capable of converging the incident light emitted by the light source 10 to form a first focused light beam P1.

[0049] The second optical element group 22 is capable of receiving the first reflected light beam F1 and folding back the first reflected light beam F1. The second optical element group 22 is also capable of converging the folded-back light to form a second focused light beam P2.

[0050] In some examples, after the second focused light beam P2 is focused on the second focal point A2 on the surface of the element to be detected 2, the second focused light beam P2 can be directly propagated to the photodetector 30 through reflection, refraction, and / or transmission, or the like, so that the photodetector 30 acquires image information and / or light intensity information of the light spot.

[0051] In other examples, after the second focused light beam P2 is focused on the second focal point A2 on the surface of the element to be detected 2, the second focused light beam P2 can be focused on the surface of the element to be detected 2 again or multiple times through the first optical element group 21, the second optical element group 22, and / or other optical elements, and form focal points at which the light spots coincide.

[0052] The light spot at the first focal point A1 and the light spot at the second focal point A2 coincide, which means that the light spot at the first focal point A1 and the light spot at the second focal point A2 substantially completely coincide, and can exactly coincide or have a slight deviation due to the tolerance of the optical elements (the deviation is very small relative to the size of the entire light spot).

[0053] The photodetector 30 can detect image information of the light spot, such as the shape and size of the light spot. The photodetector 30 can also detect light intensity information of the light spot, and further acquire the power density of the light spot.

[0054] The auxiliary irradiation device 1 provided by the embodiment of the present application is provided with an optical assembly 20. The incident light emitted by the light source 10 is guided by the optical assembly 20 so as to be focused on the surface of the to-be-detected element 2 at least twice, and the light spots at the focal points formed on the surface of the to-be-detected element 2 are coincident, which can make the electrons on the surface of the to-be-detected element 2 absorb more photon energy, generate greater energy level transition, and be beneficial to the electron beam detection equipment to obtain more electrons and more surface information of the to-be-detected element 2 and higher detection efficiency. The embodiment of the present application improves the number of electrons excited at the light spot by the focusing mode, which is beneficial to improve the detection accuracy and detection efficiency, and can reduce the power requirement of the light source 10, reduce the volume and weight of the light source 10, and is beneficial to integrate the light source 10 into the electron beam detection equipment 3 and reduce the cost.

[0055] The photoelectric detector 30 can obtain the image information and / or light intensity information of the light spot, monitor whether the shape and size of the light spot meet the requirements, whether the light power density of the light spot has large fluctuation, and the like, which is beneficial to timely adjust the position of the light spot or compensate the incident light to improve the reliability and stability of the detection equipment.

[0056] In some embodiments, the second focused light beam P2 is reflected by the surface of the to-be-detected element 2 to form a second reflected light beam F2 which is directed to the first optical element group 21. The first optical element group 21 is configured to direct the second reflected light beam F2 to the photoelectric detector 30.

[0057] The second reflected light beam F2 carries the image information and / or light intensity information of the light spot at the second focal point A2, and the light spot at the second focal point A2 is coincident with the light spot at the first focal point A1. Therefore, the photoelectric detector 30 can detect the image information and / or light intensity information of the light spot formed on the surface of the to-be-detected element 2 after receiving the second reflected light beam F2.

[0058] The embodiment of the present application utilizes the first optical element group 21 to guide the second reflected light beam F2 to the photoelectric detector 30, which does not need to additionally set other optical elements, is beneficial to simplify the optical path structure of the auxiliary irradiation device 1, can block the second reflected light beam F2 from returning to the light source 10, reduce the adverse effect of the second reflected light beam F2 on the light source 10, and is beneficial to improve the stability.

[0059] In some embodiments, the first optical element group 21 includes an optical path selection assembly 211 and a first focusing member 212 which are optically connected. The optical path selection assembly 211 is used for transmitting the incident light emitted by the light source 10 to the first focusing member 212, and is also used for reflecting the second reflected light beam F2 emitted from the first focusing member 212 to the photoelectric detector 30. The first focusing member 212 is used for forming the first focused light beam P1.

[0060] The light path selection component 211 can include a component formed by part of a light transmission element, a light reflection element, a polarizer, a wave plate, or other suitable optical elements.

[0061] The first focusing element 212 can converge light rays. The light rays transmitted by the light path selection component 211 to the first focusing element 212 can be parallel light rays, and the first focusing element 212 can converge the incident parallel light into a light spot. The light rays reflected by the surface of the to-be-detected element 2 can be divergent light, and the first focusing element 212 can also converge the incident divergent light into parallel light.

[0062] The first focusing element 212 can include a focusing lens or other optical elements capable of converging light rays.

[0063] The light path selection component 211 can selectively guide the light paths of different light rays. The light path selection component 211 can transmit the incident light rays emitted by the light source 10, so that the incident light rays can pass through the light path selection component 211 without loss or with small loss, which is beneficial to improve the intensity of the light rays directed to the first focusing element 212, and further improve the intensity of the light spot at the first focal point A1. The light path selection component 211 can also reflect the second reflected light beam F2 emitted by the first focusing element 212 towards the photodetector 30, prevent the second reflected light beam F2 from returning to the light source 10 through the light path selection component 211, and allow the photodetector 30 to receive the second reflected light beam F2.

[0064] In some embodiments, the light path selection component 211 includes a polarization component 2111 and a quarter wave plate 2112, and the quarter wave plate 2112 is arranged between the polarization component 2111 and the first focusing element 212 along the propagation direction of the incident light rays.

[0065] The polarization direction of the polarization component 2111 is consistent with the polarization direction of the incident light rays emitted by the light source 10, and the polarization component 2111 is used to adjust the incident light rays emitted by the light source 10 into incident linearly polarized light rays and transmit them to the quarter wave plate 2112. The quarter wave plate 2112 is used to adjust the incident linearly polarized light rays into incident circularly polarized light rays and transmit them to the first focusing element 212. The quarter wave plate 2112 is also used to adjust the reflected circularly polarized light rays emitted from the first focusing element 212 into reflected linearly polarized light rays and transmit them to the polarization component 2111, and the polarization direction of the reflected linearly polarized light rays is perpendicular to the polarization direction of the polarization component 2111. The polarization component 2111 is used to reflect the reflected linearly polarized light rays to the photodetector 30.

[0066] The polarization component 2111 can be a polarizer.

[0067] The polarization direction of the polarization component 2111 is consistent with the polarization direction of the incident light emitted by the light source 10, and the incident light can pass through the polarization component 2111 almost without attenuation, realizing the transmission of the incident light. After passing through the quarter-wave plate 2112, the incident light is restored to circularly polarized light, which is convenient for uniformly irradiating the first focusing component 212. The first focusing component 212 can converge the incident circularly polarized light irradiating it to form a first focused light beam P1, which is convenient for forming a first focal point A1 on the surface of the detection element 2. The first focused light beam P1 is reflected by the surface of the detection element 2 to form a first reflected light beam F1, the first reflected light beam F1 is folded by the second optical element group 22 to form a second focused light beam P2, the second focused light beam P2 is reflected by the surface of the detection element 2 to form a second reflected light beam F2, and the second reflected light beam F2 becomes a reflected circularly polarized light after irradiating the first focusing component 212. After passing through the quarter-wave plate 2112, the reflected circularly polarized light becomes reflected linearly polarized light. Since the polarization direction of the reflected linearly polarized light is perpendicular to the polarization direction of the polarization component 2111, the reflected linearly polarized light irradiating the polarization component 2111 is reflected to the photodetector 30.

[0068] The embodiments of the present application adjust the polarization direction of light through the polarization component 2111 and the quarter-wave plate 2112, realize selective transmission or reflection of light, which is convenient for reducing energy loss in the process of light propagation, simplifying the structure of the light path selection assembly 211, and reducing the cost of the auxiliary irradiation device 1.

[0069] In some embodiments, the first optical element group 21 includes a first focusing component 212 for forming a first focused light beam P1, and the second optical element group 22 includes a second focusing component 221 for forming a second focused light beam P2. The optical axis of the first focusing component 212 forms a first included angle α with the surface of the detection element 2, the optical axis of the second focusing component 221 forms a second included angle β with the surface of the detection element 2, the first included angle α is equal to the second included angle β, and both the first included angle α and the second included angle β are less than 90°.

[0070] The second focusing component 221 can converge light. The light reflected by the surface of the detection element 2 can be divergent light, and the second focusing component 221 can converge the divergent light into parallel light irradiating other optical elements of the second optical element group 22. The light irradiating the second focusing component 221 from other optical elements can be parallel light, and the second focusing component 221 can converge the parallel light into a light spot.

[0071] The second focusing component 221 can include a focusing lens or other optical elements capable of converging light.

[0072] The first focusing member 212 and the second focusing member 221 can have the same structure or different structures. When the first focusing member 212 and the second focusing member 221 have the same structure, the first focusing member 212 and the second focusing member 221 are symmetrically arranged.

[0073] The surface of the element 2 to be detected can be or approximately be a plane. The first angle a can be an angle between an optical axis of the first focusing member 212 and the plane. The second angle β can be an angle between an optical axis of the second focusing member 221 and the plane.

[0074] The first optical element group 21 and the second optical element group 22 form an optical structure that is symmetrical in an optical path. The second optical element group 22 can return light to the first optical element group 21 in the original path, which is conducive to reducing light loss caused by a deviation in the direction of light propagation and improving the accuracy of the detection result of the photodetector 30. In addition, it is also conducive to reducing the number of optical elements of the first optical element group 21 (for example, only one polarizer, one quarter-wave plate and one focusing member are needed), and simplifying the structure of the auxiliary illumination device 1.

[0075] In some embodiments, the first focusing member 212 and the second focusing member 221 are both focusing lenses, which have low cost and wide selection.

[0076] In some embodiments, the second optical element group 22 includes the second focusing member 221 and a light returning device 222. The second focusing member 221 is configured to transmit the first reflected light beam F1 to the light returning device 222. The light returning device 222 is configured to return the first reflected light beam F1 emitted from the second focusing member 221 to the second focusing member 221. The second focusing member 221 is further configured to form the second focused light beam P2.

[0077] The first reflected light beam F1 can be divergent light. The second focusing member 221 can converge the first reflected light beam F1 into parallel light and transmit the parallel light to the light returning device 222, which is conducive to reducing light loss.

[0078] The light returning device 222 can include one component capable of returning light or multiple components capable of returning light when combined.

[0079] The light returned by the light returning device 222 to the second focusing member 221 can be parallel light. The second focusing member 221 can converge the parallel light to form the second focused light beam P2, so that the second focused light beam P2 is focused on the second focal point A2.

[0080] In some embodiments, the light returning device 222 is configured to return the first reflected light beam F1 emitted from the second focusing member 221 to the second focusing member 221 in parallel and opposite directions.

[0081] The propagation direction of the first reflected light beam F1 out of the second focusing element 221 and the propagation direction of the light beam folded back to the second focusing element 221 are exactly opposite.

[0082] The incident light rays and the emergent light rays of the second optical element group 22 have very high parallelism, which is beneficial to the high coincidence of the light spot at the second focal point A2 with the light spot at the first focal point A1. Moreover, it is also beneficial to reduce the light loss caused by the deviation of the light propagation direction and to improve the light spot energy at the second focal point A2.

[0083] In some embodiments, the light beam folding device 222 includes a corner cube prism.

[0084] The corner cube prism can realize the folding of the light beam alone, and the parallel precision of the light incidence angle and the light emission angle of the corner cube prism is very high, which is beneficial to the coincidence of the light spots, the reduction of the light spot energy loss, the reduction of the number of optical elements included in the light beam folding device 222, the reduction of the tolerance accumulation, and the improvement of the parallel precision of the light incidence angle and the light emission angle of the light beam folding device 222.

[0085] In some embodiments, the auxiliary illumination device 1 further includes a first driving controller 40 and a second driving controller 50. The first driving controller 40 is connected to the light source 10 and is used to excite the light source 10 to emit incident light rays. The second driving controller 50 is connected to the photodetector 30 and the first driving controller 40, is used to acquire image information and / or light intensity information detected by the photodetector 30, and sends a control signal to the first driving controller 40 according to the image information and / or the light intensity information, so that the first driving controller 40 adjusts the emission power of the light source 10 according to the control signal.

[0086] Changes in temperature and other environmental factors, or the life attenuation of the light source 10 itself, can cause the light power of the light source 10 to fluctuate or decrease, thereby affecting the detection accuracy and stability.

[0087] The embodiments of the present application receive the image information and / or the light intensity information detected by the photodetector 30 through the second driving controller 50, and then judge whether the shape, size, etc. of the light spot meet the detection requirements and whether the intensity or power density of the light spot fluctuates greatly according to the image information and / or the light intensity information. When the shape, size, etc. of the light spot do not meet the detection requirements or the intensity or power density of the light spot fluctuates greatly, a control signal can be sent to the first driving controller 40 to control the first driving controller 40 to adjust the emission power or other parameters of the light source 10, so as to compensate for the power density loss of the light spot or adjust the shape, size, etc. of the light spot. The feedback adjustment of the power, etc. of the light source 10 is realized, which is beneficial to improving the detection accuracy, stability and reliability of the detection equipment.

[0088] The embodiment of the present application further provides an electron beam detection device 3, which comprises an electron beam source 4, an electron detector 5 and the auxiliary irradiation device 1 provided by any embodiment of the present application.

[0089] The electron beam source 4 is used to emit an incident electron beam a to the element 2 to be detected, and the incident electron beam a forms a detection focus D on the surface of the element 2 to be detected, and the detection focus D is located in the light spot formed by the auxiliary irradiation device 1 on the surface of the element 2 to be detected. The electron detector 5 is used to detect the outgoing electron formed after the incident electron beam a irradiates to the surface of the element 2 to be detected.

[0090] The detection focus D is located in the light spot formed by the auxiliary irradiation device 1 on the surface of the element 2 to be detected, and the electron of the atom at the detection focus D can absorb the photon energy for multiple times, so as to generate energy level transition for multiple times. The electron detector 5 can obtain more surface information, which is beneficial to improve the detection precision and the detection efficiency.

[0091] In some embodiments, the electron beam detection device 3 can further comprise a deflector, which can project the incident electron beam a emitted by the electron beam source 4 to the surface of the element 2 to be detected.

[0092] The electron beam detection device 3 of the embodiment of the present application can be used to detect the surface defects or size of a wafer. For example, the electron beam detection device 3 can be a scanning electron microscope.

[0093] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. An auxiliary illumination device for an electron beam inspection apparatus, characterized by, The auxiliary irradiation device comprises a light source, an optical assembly and a photodetector, The light source is configured to emit incident light rays; The optical assembly is configured to receive the incident light rays and guide the incident light rays to focus on a surface of a to-be-detected element at least twice; The optical assembly comprises a first optical element group and a second optical element group; The first optical element group is configured to receive the incident light rays and form a first focused light beam directed to the surface of the to-be-detected element, the first focused light beam focuses on a first focal point on the surface of the to-be-detected element and can be reflected by the surface of the to-be-detected element to form a first reflected light beam; The second optical element group is configured to receive the first reflected light beam and form a second focused light beam directed to the surface of the to-be-detected element, the second focused light beam focuses on a second focal point on the surface of the to-be-detected element; The light spot at the first focal point and the light spot at the second focal point coincide; The photodetector is configured to detect image information and / or light intensity information of the light spot.

2. The auxiliary irradiation device according to claim 1, wherein The second focused light beam is reflected by the surface of the to-be-detected element to form a second reflected light beam directed to the first optical element group; The first optical element group is configured to guide the second reflected light beam to the photodetector.

3. The auxiliary irradiation device according to claim 2, wherein The first optical element group comprises a light path selection assembly and a first focusing member, and the light path selection assembly and the first focusing member are connected in optical path; The light path selection assembly is configured to transmit the incident light rays emitted by the light source to the first focusing member and reflect the second reflected light beam emitted from the first focusing member to the photodetector, and the first focusing member is configured to form the first focused light beam.

4. The auxiliary irradiation device according to claim 3, wherein The light path selection assembly comprises a polarization component and a quarter-wave plate, and the quarter-wave plate is arranged between the polarization component and the first focusing member along the propagation direction of the incident light rays; The polarization direction of the polarization component is consistent with the polarization direction of the incident light rays emitted by the light source, and the polarization component is configured to adjust the incident light rays emitted by the light source into incident linearly polarized light rays and transmit the incident linearly polarized light rays to the quarter-wave plate; The quarter-wave plate is configured to adjust the incident linearly polarized light rays into incident circularly polarized light rays and transmit the incident circularly polarized light rays to the first focusing member, and the quarter-wave plate is also configured to adjust the reflected circularly polarized light rays emitted from the first focusing member into reflected linearly polarized light rays and transmit the reflected linearly polarized light rays to the polarization component, and the polarization direction of the reflected linearly polarized light rays is perpendicular to the polarization direction of the polarization component; The polarization component is configured to reflect the reflected linearly polarized light rays to the photodetector.

5. The auxiliary irradiation device according to claim 2, wherein The first optical element group comprises a first focusing member for forming the first focused light beam, and the second optical element group comprises a second focusing member for forming the second focused light beam. An optical axis of the first focusing element forms a first angle with a surface of the element to be detected, and an optical axis of the second focusing element forms a second angle with the surface of the element to be detected, the first angle being equal to the second angle and both being less than 90°.

6. The auxiliary irradiation device according to claim 5, wherein The first focusing element and the second focusing element are both focusing lenses.

7. The auxiliary irradiation device according to claim 1, wherein The second optical element group comprises a second focusing element and a light ray folding device; The second focusing element is configured to transmit the first reflected light beam to the light ray folding device, the light ray folding device is configured to fold the first reflected light beam exiting from the second focusing element to the second focusing element, and the second focusing element is further configured to form the second focused light beam.

8. The auxiliary irradiation device according to claim 7, wherein The light ray folding device is configured to fold the first reflected light beam exiting from the second focusing element to the second focusing element in parallel and opposite directions.

9. The auxiliary irradiation device according to claim 7, wherein The light ray folding device comprises a corner cube prism.

10. The supplemental illumination device of claim 1, wherein, Further comprising: a first driving controller connected to the light source and configured to excite the light source to emit the incident light rays; and a second driving controller connected to the photodetector and the first driving controller, configured to acquire the image information and / or light intensity information detected by the photodetector, and send a control signal to the first driving controller according to the image information and / or light intensity information, so that the first driving controller adjusts the emission power of the light source according to the control signal.

11. An electron beam detection device, comprising: an electron beam source configured to emit an incident electron beam to an element to be detected, the incident electron beam forming a detection focal point on a surface of the element to be detected; an electron detector configured to detect outgoing electrons formed after the incident electron beam is irradiated to the surface of the element to be detected; and an auxiliary irradiation device according to any one of claims 1-10, the detection focal point being located within the light spot. ​

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