Micro-nano precision defect detection device based on Fourier leaf surface detection

Abstract

The invention relates to a defect detection device with micro-nano precision based on Fourier leaf surface detection. The defect detection device comprises a light source, a linear gradient filter, a polaroid, a relay lens group, a plane spectroscope, a microscope objective, a rear-end lens group, a frequency spectrum surface and a camera, the linear gradient filter, the polaroid and the relay lens group are sequentially and coaxially arranged according to a horizontal light path from left to right, the plane spectroscope is arranged behind the relay lens group, a 45-degree angle is formed between the mirror surface of the plane spectroscope and the horizontal direction, the microscope objective is arranged below the plane spectroscope and is aligned with a sample to be detected, and the microscope objective is arranged on the plane spectroscope. The rear-end lens group and the spectrum surface are sequentially arranged above the plane spectroscope from bottom to top, and the camera is installed above the spectrum surface and used for detecting spectrum surface light information of the object to be detected. According to the invention, optical information including continuous measurement wave bands and continuous measurement angles can be collected simultaneously.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of micro-nano manufacturing technology, and in particular to a micro-nano precision defect detection device based on Fourier plane detection. BACKGROUND

[0002] In the micro-nano field represented by integrated circuits and micro-optics, there is a wide demand for accurate measurement and control of three-dimensional topography parameters or specific topography parameters of micro-nano structures. It is crucial to accurately measure the geometric feature parameters of key process structures quickly, at low cost and non-destructively during the manufacturing process. At present, the single-angle multi-band spectral scattering measurement scheme represented by the American company KLA-Tencor is widely used in the industry and can widely realize nanometer-level precision three-dimensional topography measurement. The single-band, multi-angle angular spectrum scattering measurement scheme represented by the European Dutch company ASML can also be applied to nanometer-level precision three-dimensional topography measurement.

[0003] However, both the single-color angular spectrum type and the single-angle spectral type face the problem of insufficient amount of collected information, which cannot be accurately measured and has high process adaptability. Although the industry has made up for it in algorithms in recent years, it still cannot meet the needs of various complex process conditions. In particular, for transparent wafer substrates such as glass and compound semiconductors, traditional spectral and angular spectral schemes cannot effectively measure them. SUMMARY

[0004] To solve the above technical problems, the purpose of the present application is to provide a micro-nano precision defect detection device based on Fourier plane detection.

[0005] To achieve the above purpose, the present application adopts the following technical scheme: A micro-nano precision defect detection device based on Fourier plane detection, comprising a light source, a linearly variable filter, a polarizer, a relay lens group, a plane beam splitter, a microscope objective, a rear end lens group, a spectral plane and a camera; The linearly variable filter, the polarizer and the relay lens group are coaxially arranged in the horizontal light path from left to right, the plane beam splitter is arranged behind the relay lens group, the mirror surface of the plane beam splitter is at an angle of 45 degrees with the horizontal direction, the microscope objective is arranged below the plane beam splitter and is aligned with the sample to be measured, and the rear end lens group and the spectral plane are sequentially arranged above the plane beam splitter from bottom to top, and the camera is installed above the spectral plane and is used to detect the spectral plane light information of the object to be measured; After the light source is shaped by the light beam, the incident light is continuously filtered by the linearly varying filter, then passes through the polarizer to select the best polarization state, passes through the relay lens group for re-shaping, then passes through the plane beam splitter to be incident on the microscope objective, the incident light beam is converged by the microscope objective and then is incident on the sample to be measured, the light beam incident on the sample to be measured will be scattered and reflected, the reflected and scattered light is collected by the microscope objective and then enters the rear lens group through the beam splitter, and finally the camera collects the light signal on the spectrum plane.

[0006] Preferably, the micro-nano precision defect detection device based on Fourier plane detection can generate continuously varying light wave bands when the linearly varying filter is a continuous filter.

[0007] Preferably, the micro-nano precision defect detection device based on Fourier plane detection can adjust the wave band range of the incident light by adjusting the light transmission position of the linearly varying filter, and the wave band range is 350-800 nm.

[0008] Preferably, the micro-nano precision defect detection device based on Fourier plane detection uses a common white light source as the light source.

[0009] Preferably, the micro-nano precision defect detection device based on Fourier plane detection uses a common white light source as the light source.

[0010] Preferably, the micro-nano precision defect detection device based on Fourier plane detection has a spectrum plane, which is a Fourier plane (Pupil Plane) and can simultaneously detect and collect light signals containing multiple wave bands and multiple angle information.

[0011] The above-mentioned scheme has at least the following advantages: The measurement process of the present application has better adaptability: it can simultaneously collect light information containing continuous measurement wave bands and continuous measurement angles. The light energy utilization rate of the present application is higher: without the traditional narrow band filter, the light energy is used to the maximum extent.

[0012] The above description is only a summary of the technical scheme of the present application. In order to more clearly understand the technical means of the present application and to implement the content of the specification, the following will describe the preferred embodiments of the present application in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0014] Figure 1 is a structural schematic diagram of the present application; Figure 2 is a frequency spectrum plane signal diagram of the present application; Figure 3a is a simulation analysis measurement comparison diagram of the present application Figure 3b is Figure 3a a prior simulation analysis measurement diagram; Figure 4a is a simulation analysis measurement sensitivity comparison diagram of the present application; Figure 4b is Figure 4a a prior simulation analysis measurement diagram. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, not all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0016] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of the present application.

[0017] Embodiment one As shown in Figure 1 , a micro-nano precision defect detection device based on Fourier plane detection, a plurality of continuously gradually changing wave bands of light are incident on the sample to be measured at different angles respectively, and are collected through a microscope objective, until the light signals containing the topographic information of the object to be measured are simultaneously collected and obtained using a photodetector in the frequency spectrum plane, and the light signals are analyzed and processed, and then the topographic parameter information of the object to be measured is obtained.

[0018] The defect detection device comprises a light source 1, a linear gradient filter 2, a polarizer 3, a relay lens group 4, a plane beam splitter 5, a microscope objective 6, a rear end lens group 7, a spectrum plane 8 and a camera 9; the linear gradient filter 2, the polarizer 3 and the relay lens group 4 are coaxially arranged in sequence from left to right along a horizontal light path, the plane beam splitter 5 is arranged behind the relay lens group, the mirror surface of the plane beam splitter is at an angle of 45 degrees with the horizontal direction, the microscope objective 6 is arranged below the plane beam splitter 5 and is aligned with the sample to be measured, the rear end lens group 7 and the spectrum plane 8 are sequentially arranged above the plane beam splitter 5 from bottom to top, and the camera 9 is installed above the spectrum plane 8 and is used for detecting the spectrum plane light information of the object to be measured. Specifically, the light source is shaped by a beam shaper, the incident light is continuously filtered by the linear gradient filter, then passes through the polarizer to select the best polarization state, is reshaped by the relay lens group, then is incident on the microscope objective through the plane beam splitter, the incident light beam is converged by the microscope objective and is incident on the sample to be measured, the light beam incident on the sample to be measured is scattered and reflected, the reflected and scattered light is collected by the microscope objective, then passes through the beam splitter and enters the rear end lens group, and finally the camera collects the light signal on the spectrum plane.

[0019] In the embodiment, when the linear gradient filter 2 is a single waveband, the measuring device is a traditional monochromatic angle spectrum measuring device; when the linear gradient filter 2 is a continuous filter, a continuously variable light waveband can be generated.

[0020] By adjusting the light transmission position of the linear gradient filter, the waveband range of the incident light can be adjusted, and the waveband range is 350-800 nm.

[0021] The spectrum plane is provided with a waveband of 365-750 nm, and is also provided with an azimuth angle and an incident angle, and the angles thereof are-72°-72° around the optical axis center.

[0022] The light source is a common white light source.

[0023] The spectrum plane is a Fourier plane (Pupil Plane), and the spectrum plane can simultaneously detect and collect light signals containing multiple wavebands and multiple angle information. The optical spectrum plane is different from an image plane of optical imaging, each point of the image plane corresponds to a one-to-one relationship with an object plane before the object enters the imaging system; each point on the spectrum plane represents a specific frequency. The camera is installed on the spectrum plane and is used for detecting the spectrum plane light information of the object to be measured.

[0024] Embodiment two On the basis of the embodiment, the light source is a common white light source; after the light source is shaped by a beam shaper, a single filter is used, the filter is selected as a single waveband, and at this time, the measurement is a traditional monochromatic angle spectrum measuring device. When a linear graded-gradient filter is used, a continuously graded optical band can be generated. After the incident light passes through the linear graded-gradient filter, it is then passed through a polarizer to select the optimal polarization state (when the signal strength is maximum). After being reshaped by a relay lens group, the beam is then directed to the microscope objective by a beam splitter. The microscope objective focuses the incident beam and directs it onto the sample under test. The beam incident on the sample under test will be scattered and reflected. These reflected and scattered beams are collected by the microscope objective, passed through the beam splitter again, and then through the rear lens group. Finally, the optical signal is acquired on the spectral plane.

[0025] Figure 2 This is a spectrum diagram of the signal; after using the aforementioned linear gradient filter, the following is obtained in the spectrum diagram: Figure 2 The optical signal distribution is shown. Figure 2 In the coordinate system of the spectral surface signal diagram shown, the X-axis represents the incident light band and the Y-axis represents the incident angle; any point in the signal diagram represents a different incident angle and incident light band.

[0026] The appropriate incident light band can be selected for detection or measurement according to actual measurement needs; as shown in the figure, the 400~800nm ​​light band can be selected. Alternatively, the light transmission position of the continuous filter can be adjusted to select a light band such as 380~780nm. The specific selection depends on the operator.

[0027] When the object to be measured has a smooth surface with defects, such as nano- and micro-sized dust, scratches, pits, and protrusions, the Fourier surface light intensity distribution will change. These changes in light intensity introduced by various types of defects are drastic and contain far more information than traditional imaging, thereby improving detection sensitivity.

[0028] A simulation analysis was performed on the actual measurements for Example 2; Assuming the object under test is a periodic one-dimensional linear grating structure, with relevant parameters of period X nanometers, linewidth Y nanometers, and height Z nanometers; based on the spectral surface optical signal distribution of this invention and the traditional monochromatic angular spectrum spectral surface, as follows: Figure 3a and Figure 3b As shown.

[0029] When the grating structure is arbitrarily changed, the change in the spectral surface light signal of the present invention ( Figure 3a As shown, all are much larger than the traditional monochromatic angular spectrum scheme (as shown). Figure 3b As shown in the figure, the degree of change in the spectral surface light signal represents the sensitivity of the measurement; as follows Figure 4a As shown, when the linewidth changes by 1 nanometer, the measurement sensitivity of this invention is higher than that of conventional methods. Figure 4b More than twice that of the scheme shown.

[0030] It should be noted that like reference numerals and letters refer to like items throughout the accompanying drawings, and once an item is defined in one drawing, that definition should be applied to all like items throughout the drawings, unless otherwise specifically stated.

[0031] In the description of the present application, it should be noted that the terms "vertical", "horizontal", "inner", "outer", and the like indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed during use, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0032] In addition, the terms "horizontal", "vertical", and the like do not mean that the components must be absolutely horizontal or vertical, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0033] In the description of the present application, it should also be noted that unless otherwise specifically defined and limited, the terms "provided", "mounted", "connected", "connected" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication between two elements inside. 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.

[0034] The above is only the preferred embodiment of the present application, and is not intended to limit the present application, and it should be noted that for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should be considered as the protection scope of the present application.

Claims

1. A defect detection device with micro-nano precision based on Fourier surface methodology, characterized in that: The measuring device comprises a light source (1), a linearly variable filter (2), a polarizer (3), a relay lens group (4), a plane beam splitter (5), a microscope objective (6), a rear-end lens group (7), a spectrum plane (8) and a camera (9). The linearly variable filter (2), the polarizer (3) and the relay lens group (4) are coaxially arranged in a horizontal light path from left to right, the plane beam splitter (5) is arranged behind the relay lens group, the mirror surface of the plane beam splitter is at an angle of 45 degrees with the horizontal direction, the microscope objective (6) is arranged below the plane beam splitter (5) and is aligned with the sample to be measured, the rear-end lens group (7) and the spectrum plane (8) are sequentially arranged above the plane beam splitter (5) from bottom to top, and the camera (9) is installed above the spectrum plane (8) and is used for detecting the spectrum plane light information of the object to be measured. After the light source is shaped, the incident light is continuously filtered through the linearly variable filter, then passes through the polarizer to obtain the best polarization state, is reshaped through the relay lens group, is then incident on the microscope objective through the plane beam splitter, is focused by the microscope objective after being incident on the sample to be measured, is scattered and reflected on the sample to be measured, the reflected and scattered light is collected by the microscope objective again, enters the rear-end lens group again through the beam splitter, and finally the camera collects the light signal on the spectrum plane.

2. The micro-nano precision defect detection device based on Fourier plane detection according to claim 1, characterized in that: When the linearly variable filter (2) is a single waveband, the measuring device is a traditional monochromatic angular spectrum measuring device; when the linearly variable filter (2) is a continuous filter, a continuously variable light waveband can be generated.

3. The micro-nano precision defect detection device based on Fourier plane detection according to claim 2, characterized in that: The waveband range of the incident light can be adjusted by adjusting the light transmission position of the linearly variable filter, and the waveband range is 350-800 nm.

4. The micro-nano precision defect detection device based on Fourier plane detection according to claim 1, characterized in that: The light source is a common white light source.

5. The micro-nano precision defect detection device based on Fourier plane detection according to claim 1, characterized in that: The spectrum plane is a Fourier plane (Pupil Plane), and the spectrum plane can simultaneously detect and collect light signals containing multiple wavebands and multiple angle information.

6. The micro-nano precision defect detection device based on Fourier plane detection according to claim 5, characterized in that: The spectrum plane is provided with a waveband of 365-750 nm, and is also provided with an azimuth angle and an incident angle, and the angles thereof are-72°-72° around the optical axis center.

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