Online spectrum inspection device

Abstract

The utility model provides an on-line spectrum inspection device which comprises an object placing platform, a light source module, an objective lens, a polariscope, a polarization analyzer, a spectrograph and a laser focus tracking module. The object placing platform is used for placing a test sample. The objective lens is arranged above the object placing platform. The light source module emits a light beam which sequentially penetrates through the polariscope and the objective lens and finally enters a test point of the test sample, and the test point is excited to emit excitation light. The object placing platform can move so as to set another test point. The laser focus tracking module emits a distance measuring laser light which penetrates through the objective lens and is emitted to the test point of the test sample so as to measure the distance between the objective lens and the test point. The exciting light sequentially penetrates through the objective lens and the polarization analyzer along an exciting light optical path and finally enters the spectrograph, and the spectrograph measures the spectrum of the exciting light.

Description

TECHNICAL FIELD

[0001] The utility model relates to an on-line spectrum inspection device. BACKGROUND

[0002] In the process of integrated circuit manufacturing, wafer quality will directly affect the production yield of integrated circuits, so the measurement of wafer quality is extremely important in the integrated circuit manufacturing process. The traditional wafer quality measurement is manually performed from test point selection, test point focusing to data analysis, which requires a lot of time, and there is currently no fast, accurate and effective method for wafer quality measurement. If a fast, accurate and effective wafer quality measurement can be provided, the production yield of integrated circuits can be greatly improved. SUMMARY

[0003] Therefore, the main purpose of the utility model is to provide an on-line spectrum inspection device, which uses optical method testing, does not directly contact the test sample, can reduce manual operation time to achieve fast wafer quality measurement, and can improve the production yield of integrated circuits.

[0004] The on-line spectrum inspection device of the utility model includes a placing platform, a light source module, an objective lens, a polarizer, an analyzer, a spectrometer and a laser focus tracking module. The placing platform is used for placing a test sample. The objective lens is arranged above the placing platform. The light source module emits a light beam, the central wavelength of which is between 260 nm and 600 nm. The light beam sequentially penetrates the polarizer and the objective lens and finally enters a test point of the test sample, which is excited to emit an excitation light. The placing platform is movable to set another test point. The objective lens is movable to change the distance between the objective lens and the test point for focusing. The laser focus tracking module emits a ranging laser light which penetrates the objective lens and finally enters the test point of the test sample, to measure the distance between the objective lens and the test point. The excitation light sequentially penetrates the objective lens and the analyzer along an excitation light optical path and finally enters the spectrometer, which measures the spectrum of the excitation light.

[0005] The online spectrum inspection device of the utility model can further include an image intercepting device, a white light source, a movable white light spectroscope and a movable white light reflector. The white light source emits white light. The movable white light spectroscope and the movable white light reflector can be arranged in the excitation light optical path or not arranged in the excitation light optical path according to use requirements. When the movable white light spectroscope and the movable white light reflector are arranged in the excitation light optical path, the white light is first reflected by the movable white light spectroscope and then penetrates the objective lens, and then is incident on the test point of the test sample. The test point reflects the white light, and the white light sequentially penetrates the objective lens and the movable white light spectroscope, and then is incident on the image intercepting device after being reflected by the movable white light reflector, so that the image intercepting device intercepts an image of the test point.

[0006] The online spectrum inspection device of the utility model can further include an adjustable optical filter arranged between the polarizer and the objective lens, so that the light beam penetrates the polarizer, is first incident on the adjustable optical filter and then is incident on the objective lens. The light source module includes a first laser, a second laser and a third laser. The first laser emits a first laser light, and the central wavelength of the first laser light is 405 nm. The second laser emits a second laser light, and the central wavelength of the second laser light is 457 nm. The third laser emits a third laser light, and the central wavelength of the third laser light is 532 nm. The adjustable optical filter can be adjusted according to test requirements, so that the first laser light, the second laser light or the third laser light is incident on the test point of the test sample.

[0007] The laser focus-pursuing module includes a ranging laser, a ranging laser detector, a ranging laser spectroscope and a ranging laser filter. The ranging laser emits the ranging laser light, and the central wavelength of the ranging laser light is greater than or equal to 730 nm. The ranging laser spectroscope allows the incident ranging laser light to be partially transmitted and partially reflected. The ranging laser filter only allows the incident ranging laser light to be reflected, and other light is directly transmitted. The ranging laser light first penetrates the ranging laser spectroscope, is then reflected by the ranging laser filter, penetrates the objective lens, and finally is incident on the test point of the test sample. The test point reflects the ranging laser light, so that the ranging laser light first penetrates the objective lens, is then reflected by the ranging laser filter and the ranging laser spectroscope, and finally is incident on the ranging laser detector. Finally, the distance between the objective lens and the test point can be obtained by calculation.

[0008] The objective lens and the ranging laser filter are arranged on the objective lens platform, the objective lens platform is movable to adjust the distance between the objective lens and the test point, and the ranging laser filter is connected with the objective lens and the objective lens platform. BRIEF DESCRIPTION OF DRAWINGS

[0009] The advantages of the above features of the present application will become more apparent and easily understood from the following description of exemplary embodiments thereof in conjunction with the accompanying drawings.

[0010] Figure 1 Fig. 1 is a schematic diagram of an embodiment of the on-line spectral inspection device of the present application.

[0011] Figure 2 Fig. 2 is a schematic diagram of the white light optical path of an embodiment of the on-line spectral inspection device of the present application.

[0012] Figure 3 Fig. 3 is a schematic diagram of the ranging laser light optical path of an embodiment of the on-line spectral inspection device of the present application.

[0013] Figure 4 Fig. 4 is a schematic diagram of the laser light optical path of an embodiment of the on-line spectral inspection device of the present application.

[0014] Figure 5 Fig. 5 is a schematic diagram of the excitation light optical path of an embodiment of the on-line spectral inspection device of the present application.

[0015] Figure 6 Fig. 6 is a flowchart of the on-line spectral inspection method of the present application.

[0016] Main component symbol explanation

[0017] 1 on-line spectral inspection device

[0018] 10 light source module

[0019] 11 first laser

[0020] 12 second laser

[0021] 13 third laser

[0022] 20 objective lens

[0023] 31 white light source

[0024] 32 image intercepting device

[0025] 33 movable white light spectroscope

[0026] 34 movable white light reflector

[0027] 40 laser focus tracking module

[0028] 41 range-finding laser

[0029] 42 range-finding laser detector

[0030] 43 range-finding laser filter

[0031] 44 range-finding laser beamsplitter

[0032] 50 tunable filter

[0033] 60 focusing lens

[0034] 70 spectrometer

[0035] 80 objective stage

[0036] 85 sample stage

[0037] 90 excitation light filter

[0038] P1, P2, P3 polarizer

[0039] BS1, BS2, BS3 beamsplitter

[0040] M1, M2 mirror

[0041] A analyzer

[0042] DUT device under test

[0043] 311 white light

[0044] 411 range-finding laser light

[0045] 111 first laser light

[0046] 112 first excitation light

[0047] 121 second laser light

[0048] 122 second excitation light

[0049] 131 third laser light

[0050] 132 third excitation light DETAILED DESCRIPTION

[0051] Referring to FIG. 1, which is a schematic diagram of an embodiment of an online spectral inspection device according to the present application. The online spectral inspection device 1 includes a light source module 10, an objective lens 20, a white light source 31, an image intercepting device 32, a movable white light beam splitter 33, a movable white light beam reflector 34, a laser focus tracking module 40, an adjustable filter 50, a focusing lens 60, a spectrometer 70, an objective lens platform 80, an object platform 85, an excitation light filter 90, three polarizers P1, P2, P3, an analyzer A, three beam splitters BS1, BS2, BS3, and two mirrors M1, M2.

[0052] The light source module 10 includes a first laser 11, a second laser 12, and a third laser 13. The first laser 11 emits a first laser light having a center wavelength of 405 nm, the second laser 12 emits a second laser light having a center wavelength of 457 nm, and the third laser 13 emits a third laser light having a center wavelength of 532 nm. In this embodiment, the light source module 10 emits a light beam, which can be the first laser light, the second laser light, or the third laser light.

[0053] The laser focus tracking module 40 includes a range-finding laser 41, a range-finding laser detector 42, a range-finding laser filter 43, and a range-finding laser beam splitter 44. The range-finding laser 41 emits a range-finding laser light having a center wavelength greater than or equal to 730 nm.

[0054] The objective lens 20, the movable white light beam splitter 33, and the range-finding laser filter 43 are disposed on the objective lens platform 80, which is movable to adjust the distance between the objective lens 20 and the object platform 85. The movable white light beam splitter 33 and the movable white light beam reflector 34 are movable to change positions.

[0055] The online spectral inspection device according to the present application can be applied to the detection of a semiconductor wafer surface. A test point on the semiconductor wafer surface is irradiated with laser light to cause the test point on the wafer surface to emit excitation light. The spectrum of the excitation light is analyzed by the spectrometer to obtain the stress value of the test point. Further, the stress values of more test points are obtained by measuring different test points, so that the quality of the semiconductor wafer can be further determined. Alternatively, different wavelengths of laser light can be used to irradiate the same test point. The detection process can be further described by the following steps.

[0056] Step 1: Place a test sample (e.g., a semiconductor wafer), set a test point, and focus the test point.

[0057] Step two: measure the distance between the objective lens and the test point to which the focusing is completed using the laser focus chasing module, and define the distance as the working distance of the objective lens.

[0058] Step three: irradiate the test point with the laser light emitted by the light source module, and the test point is excited to emit excitation light, which finally enters the spectrometer. The spectrum of the excitation light is analyzed by the spectrometer, and the stress value is calculated. Other laser lights can also be set to irradiate the same test point, and the test point is excited to emit different excitation lights. Different excitation lights finally enter the spectrometer, and the spectrum of the different excitation lights is analyzed by the spectrometer, and the stress value is calculated.

[0059] Step four: set a new test point, and the laser focus chasing module synchronously measures the distance between the objective lens and the new test point. Adjust the distance between the objective lens and the new test point until the distance is equal to the working distance of the objective lens, and then stop adjusting the distance between the objective lens and the new test point.

[0060] Step five: irradiate the new test point with the laser light emitted by the light source module, and analyze the spectrum of the excitation light by the spectrometer, and calculate the stress value. Other laser lights can also be set to irradiate the new test point, and the new test point is excited to emit different excitation lights. Different excitation lights finally enter the spectrometer, and the spectrum of the different excitation lights is analyzed by the spectrometer, and the stress value is calculated.

[0061] Step six: repeat steps four to five according to the number of test points to measure the spectrum of the excitation light of different test points, and calculate the stress value.

[0062] The light source module 10 of the online spectrum inspection device 1 of the utility model is provided with three light sources for selection, which are a first laser 11, a second laser 12 and a third laser 13. The first laser 11 emits first laser light 111 with a center wavelength of 450 nm. The second laser 12 emits second laser light with a center wavelength of 457 nm. The third laser 13 emits third laser light with a center wavelength of 532 nm. The user can select one of the laser lights as the test beam according to the test requirements in step three. In addition, the number of test points is also determined by the user. Generally, a cross-shaped line has 17 test points.

[0063] The optical paths of various lights (beams) in the above steps will be described in further detail below.

[0064] Referring to FIG. 2, which is a schematic diagram of a white light optical path according to an embodiment of the on-line spectral inspection device of the present application. First, a test sample DUT is placed on the object platform 85. It is determined that the movable white light beamsplitter 33 and the movable white light mirror 34 are disposed in an excitation light optical path, which is defined by the connection of the test sample DUT, the objective lens 20, the ranging laser filter 43, the tunable filter 50, the excitation light filter 90, the turning through the polarizer A to the focusing lens 60. The movable white light beamsplitter 33 is disposed in the excitation light optical path between the objective lens 20 and the ranging laser filter 43. The movable white light mirror 34 is disposed in the excitation light optical path between the ranging laser filter 43 and the tunable filter 50. The white light source 31 is turned on to emit a white light 311. The white light 311 is first directed to the movable white light beamsplitter 33. The movable white light beamsplitter 33 allows part of the white light 311 to pass through and part of the white light 311 to be reflected. Thus, part of the white light 311 is reflected to the objective lens 20. The white light 311 is focused by the objective lens 20 and finally irradiates a test point on the test sample DUT. The test point reflects the white light 311, which is sequentially passed through the objective lens 20, the movable white light beamsplitter 33 and the ranging laser filter 43, and is reflected by the movable white light mirror 34 to enter the image pickup device 32. The ranging laser filter 43 only reflects the ranging laser light (center wavelength greater than or equal to 730 nm) and other light (white light 311) directly passes through. The movable white light mirror 34 reflects the white light 311. The image pickup device 32 is used to pick up the image of the test point. The position of the objective lens platform 80 is adjusted to change the distance between the objective lens 20 and the test point. When the image pickup device 32 picks up a clear image of the test point, it means that the test point is focused. The connection of the white light source 31 to the movable white light beamsplitter 33 and the turning through the objective lens 20 to the test sample DUT is the incident optical path of the white light 311. The connection of the test sample DUT through the objective lens 20, the movable white light beamsplitter 33, the ranging laser filter 43, the movable white light mirror 34 and the turning to the image pickup device 32 is the reflected optical path of the white light 311.

[0065] Please refer to FIG. 3, which is a schematic diagram of the optical path of the ranging laser according to the embodiment of the online spectrum inspection device of the present application. Before the ranging laser module 40 performs ranging, the movable white light beam splitter 33 and the movable white light mirror 34 are moved out of the optical path of the excitation light. The ranging laser 41 is turned on, and the ranging laser 41 emits a ranging laser light 411 (center wavelength greater than or equal to 730 nm). The ranging laser light 411 is first emitted toward the ranging laser beam splitter 44. The ranging laser beam splitter 44 allows part of the ranging laser light 411 to penetrate and part of the ranging laser light 411 to reflect. Therefore, part of the ranging laser light 411 directly penetrates the ranging laser beam splitter 44 and is emitted toward the ranging laser filter 43. The ranging laser filter 43 only reflects the ranging laser light 411, and other light directly penetrates. Therefore, the ranging laser light 411 is reflected by the ranging laser filter 43 and is emitted toward the objective lens 20. The ranging laser light 411 is focused by the objective lens 20 and finally irradiates the test point of the test sample DUT. The test point reflects the ranging laser light 411, which first penetrates the objective lens 20 and then sequentially reflects the ranging laser filter 43 and the ranging laser beam splitter 44 and is incident to the ranging laser detector 42. After calculation, the distance between the objective lens 20 and the test point that has been focused can be obtained, and this distance is defined as an objective lens working distance. The connection of the ranging laser 41 through the ranging laser beam splitter 44 to the ranging laser filter 43, the connection through the objective lens 20 to the test sample DUT, and the connection of the test sample DUT through the objective lens 20 to the ranging laser filter 43, the connection to the ranging laser beam splitter 44, and the connection to the ranging laser detector 42 are the incident optical path of the ranging laser light 411. The connection of the test sample DUT through the objective lens 20 to the ranging laser filter 43, the connection to the ranging laser beam splitter 44, and the connection to the ranging laser detector 42 are the reflection optical path of the ranging laser light 411.

[0066] Please refer to FIG. 4, which is a schematic diagram of a laser optical path of an embodiment of the online spectrum inspection device according to the present application. Before the excitation light spectrum measurement, the movable white light beam splitter 33 and the movable white light mirror 34 are moved out of the excitation light optical path. The first laser 11 is turned on, and the first laser light 111 is emitted. The first laser light 111 is first incident on the polarizer P1 and then is reflected to the beam splitter BS1. The beam splitters BS1, BS2 and BS3 allow part of the first laser light 111 to penetrate and part of the first laser light 111 to be reflected. Therefore, part of the first laser light 111 is reflected by the beam splitter BS1, and then sequentially penetrates the beam splitters BS2 and BS3, and is reflected by the mirrors M1 and M2 to be incident on the adjustable filter 50. The adjustable filter 50 has three operating modes, which are only reflecting the first laser light and allowing other light to penetrate, only reflecting the second laser light and allowing other light to penetrate, and only reflecting the third laser light and allowing other light to penetrate. Therefore, the adjustable filter 50 is selected to be in the mode of only reflecting the first laser light and allowing other light to penetrate. The first laser light 111 is reflected and then sequentially penetrates the ranging laser filter 43 and the objective lens 20. The first laser light 111 is focused by the objective lens 20 and finally irradiates the test point of the test sample DUT. The incident optical path of the first laser light 111 is from the first laser 11 to the polarizer P1, then to the beam splitter BS1, then to the beam splitters BS2 and BS3, then to the mirror M1, then to the mirror M2, then to the adjustable filter 50, then to the ranging laser filter 43, then to the objective lens 20, and finally to the test sample DUT. If the second laser is set, the second laser 12 is turned on, and the second laser light 121 is emitted. The second laser light 121 is first incident on the polarizer P2 and then is reflected to the beam splitter BS2. The beam splitters BS2 and BS3 allow part of the second laser light 121 to penetrate and part of the second laser light 121 to be reflected. Therefore, part of the second laser light 121 is reflected by the beam splitter BS2, and then penetrates the beam splitter BS3. The optical path of the second laser light 121 from the beam splitter BS3 to the test sample DUT is the same as that of the first laser light 111. The incident optical path of the second laser light 121 is from the second laser 12 to the polarizer P2, then to the beam splitter BS2, then to the beam splitter BS3, and then to the test sample DUT through a common optical path with the first laser light 111. If the third laser is set, the third laser 13 is turned on, and the third laser light 131 is emitted.The third laser light 131 first enters the polarizer P3 and then is reflected to the beamsplitter BS3. The beamsplitter BS3 allows part of the third laser light 131 to pass through, so part of the third laser light 131 is reflected by the beamsplitter BS3. The optical path between the third laser light 131 and the test sample DUT is the same as that of the first laser light 111 and the second laser light 121. The third laser light 131 is reflected by the polarizer P3 and then is reflected by the beamsplitter BS3. The third laser light 131 passes through the optical path which is collinear with the first laser light 111 and the second laser light 121 (from the beamsplitter BS3 to the test sample DUT) to form the incident optical path of the third laser light 131.

[0067] Please refer to FIG. 5, which is a schematic diagram of the optical path of the excitation light of the on-line spectral inspection device according to an embodiment of the present application. When the first laser light 111 irradiates the test point of the test sample DUT, the test point is excited to generate the first excitation light 112. The first excitation light 112 first passes through the objective lens 20, then sequentially passes through the distance laser filter 43 and the adjustable filter 50, and then enters the excitation light filter 90. After being reflected by the excitation light filter 90, the first excitation light 112 enters the polarizer A, and finally is focused by the focusing lens 60 to enter the spectrometer 70. The spectrum of the first excitation light 112 is analyzed by the spectrometer 70, and then the stress value of the test point is calculated. The test sample DUT passes through the objective lens 20, the distance laser filter 43, the adjustable filter 50, the excitation light filter 90, and the polarizer A to the focusing lens 60 to form the incident optical path of the first excitation light 112. When the second laser light 121 irradiates the test point of the test sample DUT, the test point is excited to generate the second excitation light 122. The incident optical path of the second excitation light 122 is the same as that of the first excitation light 112. Finally, the spectrum of the second excitation light 122 is analyzed by the spectrometer 70, and then the stress value of the test point is calculated. When the third laser light 131 irradiates the test point of the test sample DUT, the test point is excited to generate the third excitation light 132. The incident optical path of the third excitation light 132 is the same as that of the first excitation light 112 and the second excitation light 122. Finally, the spectrum of the third excitation light 132 is analyzed by the spectrometer 70, and then the stress value of the test point is calculated.

[0068] The on-line spectral inspection method of the present application is described below in combination with FIG. 6.

[0069] Firstly, as shown in step S110, a white light is generated and irradiates a test point of a test sample. In some embodiments, the white light is first focused and then irradiates the test point.

[0070] Then, as shown in step S120, a distance between an objective lens and the test point is adjusted by moving the objective lens, so that a clear image of the test point can be captured by an image capturing device, thereby completing the focusing of the test point.

[0071] Next, as step S130, a ranging laser light is generated and irradiated to the test point of the test sample, and the distance between the objective lens and the test point after focusing is calculated, which is defined as an objective lens working distance. In some embodiments, the ranging laser light is first focused by the objective lens and then irradiated to the test point.

[0072] Next, as step S140, a test laser light is generated and first enters a polarizer and then irradiates to the test point of the test sample, the test point is excited to generate an excitation light, the excitation light enters an analyzer and then enters a spectrometer, the spectrometer analyzes the spectrum of the excitation light, and a stress value is calculated. In some embodiments, the test laser light penetrates the polarizer and is focused by the objective lens and then irradiated to the test point.

[0073] Next, as step S150, is another test laser light set? When the user selects to set another test laser light, then step S140 is performed, and when the user selects not to set another test laser light, then step S160 is performed.

[0074] Step S160, is the test sample moved so that the ranging laser light irradiates another test point of the test sample to set the other test point? When the user selects to set the other test point, then step S170 is performed, and when the user selects not to set the other test point, the test is ended.

[0075] Step S170, is the other distance between the objective lens and the other test point equal to the objective lens working distance? When the other distance between the objective lens and the other test point is equal to the objective lens working distance, then step S140 is performed, and when the other distance between the objective lens and the other test point is not equal to the objective lens working distance, then step S180 is performed. In some embodiments, the ranging laser light is first focused by the objective lens and then irradiated to the other test point, and the other distance between the objective lens and the other test point is calculated.

[0076] Step S180, adjust the other distance between the objective lens and the other test point, and then step S170 is performed.

[0077] Although the present application has been disclosed with reference to the preferred embodiments, it is not intended to limit the present application, and anyone with ordinary knowledge in the art can make some changes and modifications without departing from the spirit and scope of the present application, therefore the protection scope of the present application is defined by the appended patent claims.

[0078] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall fall into the scope of protection of the present application.

Claims

1. An online spectral inspection device, comprising: A storage platform; a light source module; an objective lens; a polarizing microscope; an analyzer; and a spectrometer. And a laser autofocus module; The platform is used to place a test sample; the objective lens is positioned above the platform; the light source module emits a light beam with a center wavelength between 260 nm and 600 nm, which sequentially passes through the polarizer and the objective lens, and finally enters a test point on the test sample, where an excitation light is emitted; the platform is movable to set another test point; the objective lens is movable to change the distance between the objective lens and the test point for focusing; the laser tracking module emits a ranging laser light that passes through the objective lens and finally enters the test point on the test sample to measure the distance between the objective lens and the test point. The excitation light passes sequentially through the objective lens and the analyzer along an excitation light optical path, and finally enters the spectrometer, which measures the spectrum of the excitation light.

2. The online spectral inspection device according to claim 1, further comprising: An image capture device; a white light source; A movable white light beam splitter; And a movable white light reflector; The white light source emits white light; the movable white light beam splitter and the movable white light reflector can be placed in or not placed in the excitation light optical path according to the usage requirements; when the movable white light beam splitter and the movable white light reflector are placed in the excitation light optical path, the white light can be reflected by the movable white light beam splitter and then pass through the objective lens, and then enter the test point of the test sample. The test point reflects the white light, so that the white light passes through the objective lens and the movable white light beam splitter in sequence, and then is reflected by the movable white light reflector and enters the image capturing device, so that the image capturing device captures an image of one of the test points.

3. The online spectral inspection device according to claim 1, further comprising an adjustable filter disposed between the polarizer and the objective lens, such that after the light beam passes through the polarizer, it first enters the adjustable filter and then enters the objective lens, wherein: The light source module includes a first laser, a second laser, and a third laser; the first laser emits a first laser light with a center wavelength of 405 nm; the second laser emits a second laser light with a center wavelength of 457 nm; the third laser emits a third laser light with a center wavelength of 532 nm; and the adjustable filter can be adjusted according to the test requirements so that the first laser light, the second laser light, or the third laser light is incident on the test point of the test sample.

4. The online spectral inspection device according to claim 1, wherein the laser focusing module comprises: A ranging laser that emits ranging laser light with a center wavelength greater than or equal to 730 nm; a ranging laser detector; A ranging laser beam splitter that allows incident ranging laser light to partially pass through and partially reflect; and a ranging laser filter that allows only the incident ranging laser light to reflect, while other light rays pass through directly. The ranging laser light first penetrates the ranging laser beam splitter, then is reflected by the ranging laser filter, then penetrates the objective lens, and finally enters the test point of the test sample. The test point reflects the ranging laser light, so that the ranging laser light first penetrates the objective lens, then is reflected by the ranging laser filter and the ranging laser beam splitter, and finally enters the ranging laser light detector. Finally, the distance between the objective lens and the test point can be calculated.

5. The online spectral inspection device according to claim 4 further includes an objective lens platform, the objective lens and the ranging laser filter are disposed on the objective lens platform, the objective lens platform is movable to adjust the distance between the objective lens and the test point, and the ranging laser filter and the objective lens are linked to the objective lens platform.

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