Microscope objective lens and detection system

Abstract

The embodiment of the invention provides a microscope objective lens and a detection system, which are used for providing a large-view-field large-data-value aperture microscope objective lens based on a wave band of 266nm to 520nm and improving the detection speed and resolution of semiconductor defects. The microscope objective lens in the embodiment of the invention comprises at least one negative focal power lens group, four or five positive focal power lens groups and a meniscus positive lens group which are coaxially arranged in sequence from an object space to an image space, the working wave band of the microscope objective lens comprises [266nm, 520nm], and the numerical aperture of the microscope objective lens is greater than 0.85; wherein the range of the ratio of the focal length of the at least one negative-focal-power lens group to the focal length of the microscope objective lens is [-5,-2.5]; the range of the ratio of the focal length of the four or five positive-focal-power lens groups to the focal length of the microscope objective lens is [4, 16]; the range of the ratio of the focal length of the meniscus positive lens group to the focal length of the microscope objective lens is [2.8, 3.5], and the concave surfaces of the meniscus positive lens group face the image surface.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor detection technology, and in particular to a microscope objective lens and a detection system. Background Art

[0002] Semiconductor defect detection equipment is a widely used equipment in the semiconductor process chain, covering almost every process link, and is used to detect the pass rate of the process. Semiconductor defect detection equipment has two very critical indicators: resolution and detection speed, of which resolution is related to the working band and numerical aperture, and detection rate is related to light source intensity and instrument sensitivity. The current design idea is to shorten the working band to extreme ultraviolet, such as 248nm or wide band 260-480nm. However, when the 248nm light intensity is too strong, it will damage the photoresist, affect pattern detection, and destroy the sample. Moreover, the frequency and power of the 248nm laser light source cannot be increased at the same time, and the impact on the semiconductor detection rate is relatively small. Therefore, xenon lamps are generally used as light sources in the prior art, but the power of wide-band light sources such as xenon lamps cannot match that of lasers, so the detection rate needs to be improved.

[0003] With the development of technology, high-power lasers in the 266nm band have appeared on the market. The frequency of 266nm lasers can reach 20MHz and the power is greater than 5W. That is, lasers in the 266nm band can improve both resolution and test rate. Therefore, semiconductor defect detection technology based on 266nm will become one of the solutions.

[0004] However, in the current prior art, a microscope objective lens with a large field of view and a large numerical aperture based on 266 nm has not yet been found. Summary of the invention

[0005] An embodiment of the present invention provides a microscope objective lens, which is used to provide a microscope objective lens with a large field of view and a large numerical aperture based on a light band of 266nm to 520nm, and is used to improve the detection speed and resolution of semiconductor defects.

[0006] The present application embodiment provides a microscope objective lens, comprising:

[0007] At least one negative power lens group, four or five positive power lens groups and one meniscus positive lens group are coaxially arranged in sequence from the object side to the image side, wherein the working band of the microscope objective lens includes [266nm, 520nm], and the numerical aperture of the microscope objective lens is greater than 0.85;

[0008] Wherein, the ratio of the focal length of the at least one group of negative focal power lens groups to the focal length of the microscope objective lens includes [-5, -2.5];

[0009] The ratio of the focal length of the four or five positive power lens groups to the focal length of the microscope objective lens includes [4, 16];

[0010] The ratio of the focal length of the meniscus positive lens group to the focal length of the microscope objective lens ranges from [2.8, 3.5], wherein the concave surfaces of the meniscus positive lens group all face the image plane.

[0011] Optionally, the at least one negative power lens group comprises:

[0012] A negative lens group, or two negative lens groups;

[0013] The negative lens group comprises a negative lens 1 and a negative lens 2 coaxially arranged in sequence from the object side to the image side, and the focal length range of the negative lens group comprises [-66mm, -56mm];

[0014] The two negative lens groups include a first negative lens group and a second negative lens group, the first negative lens group includes a negative lens 1′, the second negative lens group includes a positive lens 2′, a negative lens 3′, a positive lens 4′ and a negative lens 5′ coaxially arranged in sequence from the object side to the image side, the focal length range of the first negative lens group includes [-51mm, -61mm], and the focal length range of the second negative lens group includes [-763mm, -753mm].

[0015] Optionally, the four positive power lens groups include: a first positive lens group, a second positive lens group, a third positive lens group and a fourth positive lens group coaxially arranged in sequence from the object side to the image side, wherein:

[0016] The first positive lens group comprises a positive lens 3, a negative lens 4 and a positive lens 5 which are coaxially arranged in sequence from the object side to the image side, wherein the focal length of the first positive lens group comprises [360 mm, 370 mm];

[0017] The second positive lens group includes a positive lens 6, a negative lens 7, a positive lens 8, a negative lens 9 and a positive lens 10 coaxially arranged in sequence from the object side to the image side, and the focal length of the second positive lens group includes [143mm, 153mm];

[0018] The third positive lens group comprises a negative lens 11 and a positive lens 12 coaxially arranged in sequence from the object side to the image side, wherein the negative lens 11 is farther away from the image plane than the positive lens 12, and the focal length of the third positive lens group comprises [442mm, 452mm];

[0019] The fourth positive lens group includes a negative lens 13 and a positive lens 14 coaxially arranged in sequence from the object side to the image side, wherein the negative lens 13 is farther away from the image plane than the positive lens 14, and the focal length of the fourth positive lens group includes [1461mm, 1471mm].

[0020] Optionally, the five positive power lens groups include: a fifth positive lens group, a sixth positive lens group, a seventh positive lens group, an eighth positive lens group and a ninth positive lens group coaxially arranged in sequence from the object side to the image side, wherein:

[0021] The fifth positive lens group comprises a positive lens 6', a negative lens 7' and a positive lens 8' which are coaxially arranged in sequence from the object side to the image side, wherein the focal length of the fifth positive lens group comprises [249mm, 259mm];

[0022] The sixth positive lens group comprises a positive lens 9′ and a negative lens 10′ coaxially arranged in sequence from the object side to the image side, wherein the negative lens 10′ is closer to the image plane than the positive lens 9′, and the focal length of the sixth positive lens group comprises [467 mm, 477 mm];

[0023] The seventh positive lens group includes a positive lens 11′, and the focal length of the seventh positive lens group includes [383mm, 393mm];

[0024] The eighth positive lens group includes a positive lens 12′ and a negative lens 13′, wherein the negative lens 13′ is closer to the image plane than the positive lens 12′, and the focal length of the eighth positive lens group includes [453 mm, 463 mm];

[0025] The ninth positive lens group includes a positive lens 14 ′ and a negative lens 15 ′, wherein the negative lens 15 ′ is closer to the image plane than the positive lens 14 ′, and the focal length of the ninth positive lens group includes [251 mm, 351 mm].

[0026] Optionally, the coupling spacing between each lens in each positive lens group is d, wherein 0.1 mm≤d≤0.5 mm.

[0027] Optionally, if the microscope objective includes four groups of positive power lenses, the microscope objective further includes an aperture stop disposed between the negative lens 7 and the negative lens 9;

[0028] If the microscope objective includes five groups of positive power lenses, the microscope objective further includes an aperture stop disposed between the negative lens 7 ′ and the positive lens 9 ′.

[0029] Optionally, the image plane incident angle of the principal light in the microscope objective is less than 0.5°.

[0030] Optionally, the group of meniscus positive lenses comprises:

[0031] A meniscus positive lens 15, a meniscus positive lens 16 and a meniscus positive lens 17 are coaxially arranged in sequence from the object side to the image side, and the focal length range of the meniscus lens group composed of the meniscus positive lens 15, the meniscus positive lens 16 and the meniscus positive lens 17 includes [40mm, 50mm];

[0032] or;

[0033] The meniscus positive lens 16' and the meniscus positive lens 17' are coaxially arranged in sequence from the object side to the image side, and the focal length range of the meniscus lens group composed of the meniscus positive lens 16' and the meniscus positive lens 17' includes [44mm, 54mm].

[0034] Optionally, the meniscus positive lens group includes a Qiming lens group.

[0035] Optionally, the focal length range of the microscope objective lens includes [8mm, 20mm], and the length of the microscope objective lens is less than 300mm.

[0036] Optionally, the field of view of the microscope objective is greater than 1.3 mm.

[0037] Optionally, the optical resolution of the microscope objective is less than 0.3 um.

[0038] Optionally, the working distance of the microscope objective lens ranges from 1.5 mm to 2.5 mm.

[0039] Optionally, the working band of the microscope objective lens also includes 520 nm, and the focal plane of the microscope objective lens when the working band is 266 nm coincides with the focal plane of the microscope objective lens when the working band is 520 nm.

[0040] Optionally, the material of the lens close to the object side in the at least one group of negative optical focal length lens groups is fused quartz, and the material of the lens close to the image side in the meniscus positive lens group is fused quartz.

[0041] The second aspect of the embodiment of the present application provides a detection system, including a light source, an illumination lens group, the microscope objective lens provided by the first aspect of the embodiment of the present application, an imaging lens group and a detector, wherein:

[0042] The light source is used to emit a light beam to the object to be detected;

[0043] The lighting mirror assembly is used to shape the light beam emitted by the light source;

[0044] The microscope objective lens is used to magnify the features in the object to be detected;

[0045] The imaging lens assembly is used to image the features of the magnified object to be detected;

[0046] The detector is used to photograph the features in the magnified object to be detected.

[0047] It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

[0048] Because the microscope objective in the present application can image wavelengths from 266nm to 520nm, the microscope objective in the embodiment of the present application can match a high-power 266nm laser, and the frequency of the 266nm laser can reach 20MHz, and the power is greater than 5W. Therefore, when the microscope objective in the embodiment of the present application matches the 266nm high-power laser, on the one hand, it can improve the test rate of semiconductors, and the numerical aperture of the microscope objective in the embodiment of the present application is greater than 0.85. Therefore, under the premise that the wavelength of the incident light is fixed, the minimum distance between two object points that the microscope objective can distinguish is small, that is, the microscope objective in the embodiment of the present application also improves the resolution of semiconductor defects on the other hand. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of an embodiment of a microscope objective lens in an embodiment of the present application;

[0050] Figure 2 It is a schematic diagram of an embodiment of at least one negative power lens group 101 in the embodiment of the present application;

[0051] Figure 3 It is a schematic diagram of another embodiment of at least one negative power lens group 101 in the embodiment of the present application;

[0052] Figure 4 It is a schematic diagram of an embodiment of 102 composed of four positive power lens groups in the application embodiment;

[0053] Figure 5 It is a schematic diagram of another embodiment of 102 composed of five positive power lens groups in the application embodiment;

[0054] Figure 6 Schematic diagram of the incident angle of the image plane of the principal light in the embodiment of the present application;

[0055] Figure 7 This is a schematic diagram of an embodiment of a meniscus lens assembly in an embodiment of the present application;

[0056] Figure 8 This is a schematic diagram of another embodiment of the meniscus lens assembly in the embodiment of the present application;

[0057] Fig. 9 This is a point diagram of the imaging effect of the microscope objective lens in the embodiment of the present application;

[0058] Fig.10Field curvature curves are given when the microscope objective lens in the embodiment of the present application works in the 266nm band and the 520nm band;

[0059] Fig.11 Schematic diagram of another embodiment of a microscope objective lens in an embodiment of the present application. DETAILED DESCRIPTION

[0060] The embodiment of the present invention provides a microscope objective lens and a detection system, which are used to provide a microscope objective lens with a large field of view and a large numerical aperture based on 266nm to 520nm, so as to improve the detection speed and resolution of semiconductor defects.

[0061] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0062] The terms "first", "second", "third", "fourth", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0063] For ease of understanding, the microscope objective lens in the embodiment of the present application is described below. Figure 1 , an embodiment of the microscope objective lens in the embodiment of the present application includes:

[0064] At least one group of negative power lens groups 101, 4 or 5 groups of positive power lens groups 102, and a group of meniscus positive lens groups 103 are coaxially arranged in sequence from the object side to the image side, wherein the working band of the microscope objective lens includes 266nm to 520nm, and the numerical aperture is greater than 0.85.

[0065] Among them, the ratio range of the focal length of the at least one group of negative light focal power lens groups 101 to the focal length of the microscope objective lens includes [-5, -2.5]; the ratio range of the focal length of 102 composed of 4 or 5 groups of positive light focal power lens groups to the focal length of the microscope objective lens includes [4, 16]; the ratio range of the focal length of the group of meniscus positive lens groups 103 to the focal length of the microscope objective lens includes [2.8, 3.5], wherein the concave surfaces of the meniscus positive lens groups all face the image plane.

[0066] Specifically, in the embodiments of the present application, there is no specific restriction on the number of lenses in each lens group, as long as the final effect of the lenses in each lens group on the light can achieve a positive focal effect or a negative focal effect. For example, a negative focal lens group can include only one negative lens, or can include multiple positive lenses and multiple negative lenses, as long as the final combination of the multiple positive lenses and the multiple negative lenses has a negative focal effect.

[0067] Because the microscope objective in the present application can image a wavelength of 266nm, the microscope objective in the embodiment of the present application can match a high-power 266nm laser, and the frequency of the 266nm laser can reach 20MHz, and the power is greater than 5W. Therefore, when the microscope objective in the embodiment of the present application matches the 266nm high-power laser, on the one hand, it can improve the test rate of the semiconductor, and the numerical aperture of the microscope objective in the embodiment of the present application is greater than 0.85. Therefore, under the premise that the wavelength of the incident light is fixed, the minimum distance between the two object points that the microscope objective can distinguish is small, that is, the microscope objective in the embodiment of the present application also improves the resolution of semiconductor defects on the other hand.

[0068] based on Figure 1 In the embodiment described above, at least one negative power lens group 101 is described in detail below:

[0069] Specifically, the at least one negative power lens group 101 in the embodiment of the present application may include one negative lens group or two negative lens groups.

[0070] When 101 includes a negative lens group 1011, 1011 includes a negative lens 1 and a negative lens 2 coaxially arranged from the object side to the image side, and the focal length range of the negative lens group includes [-66mm, -56mm]. The material of the negative lens 1 is fused quartz. For ease of understanding, Figure 2 A schematic diagram of the composition of 1011 is given.

[0071] When 101 includes 1012 consisting of two negative lens groups, 1012 includes a first negative lens group and a second negative lens group, the first negative lens group includes: a negative lens 1', and the focal length range of the first negative lens group includes [-51mm, -61mm], the second negative lens group includes: a positive lens 2', a negative lens 3', a positive lens 4' and a negative lens 5' coaxially arranged in sequence from the object side to the image side, and the focal length range of the second negative lens group includes [-763mm, -753mm]. For ease of understanding, Figure 3 A schematic diagram of the composition of 1012 is given, in which the material of the negative lens 1′ is also fused quartz. Because when the negative lens 1 or the negative lens 1′ is made of fused quartz material, fused quartz is not easy to deliquesce, thereby avoiding the fogging phenomenon of the microscope objective lens and the problem of reducing the transmittance of the microscope objective lens due to the fogging phenomenon.

[0072] The focal length range of the microscope objective in the embodiment of the present application includes [8mm, 20mm]. It can be obtained that when 101 includes a negative lens group 1011, the ratio of the focal length of the negative lens group to the focal length of the microscope objective includes [-5, -3], and when 101 includes two negative lens groups 1012, the ratio of the focal length of the two negative lens groups to the focal length of the microscope objective includes [-3.5, -2.5].

[0073] based on Figure 1 In the embodiment described above, the following describes the four positive power lens groups 102 in the microscope objective lens:

[0074] Specifically, when the microscope objective includes four groups of positive power lens groups, the four groups of positive power lens groups respectively include:

[0075] The first positive lens group includes a positive lens 3, a negative lens 4 and a positive lens 5 which are coaxially arranged in sequence from the object side to the image side, wherein the focal length of the first positive lens group includes [360mm, 370mm].

[0076] The second positive lens group includes a positive lens 6, a negative lens 7, a positive lens 8, a negative lens 9 and a positive lens 10 which are coaxially arranged in sequence from the object side to the image side. The focal length of the second positive lens group includes [143mm, 153mm].

[0077] The third positive lens group includes a negative lens 11 and a positive lens 12 coaxially arranged in sequence from the object side to the image side, wherein the negative lens 11 is farther away from the image plane than the positive lens 12, and the focal length of the third positive lens group includes [442mm, 452mm].

[0078] The fourth positive lens group includes a negative lens 13 and a positive lens 14 coaxially arranged in sequence from the object side to the image side, wherein the negative lens 13 is farther away from the image plane than the positive lens 14, and the focal length of the fourth positive lens group includes [1461mm, 1471mm].

[0079] The focal length range of the microscope objective lens in the embodiment of the present application includes [8mm, 20mm]. It can be obtained that when 102 includes 4 groups of positive focal power lens groups, the ratio range of the focal length of the 4 groups of positive focal power lens groups to the focal length of the microscope objective lens includes [15, 16].

[0080] In the above four positive focal length lens groups, each lens in each lens group adopts separate small-pitch coupling, wherein the distance d between each coupled lens is greater than 0.1mm and less than 0.5mm, thereby avoiding the attenuation of light caused by the use of cemented lenses (because the glue layer of the cemented lens cannot withstand the irradiation of high-power lasers, it is easy to produce attenuation and reduce the transmittance).

[0081] Furthermore, when 102 includes four groups of positive focal power lens groups, the microscope objective also includes an aperture arranged between the negative lens 7 and the negative lens 9, so that the telecentricity of the entire microscope objective is very high, that is, the image plane incident angle of the main light is less than 0.5°, so that when the microscope objective is used to detect semiconductor defects, the imaging distortion of the defects is less than 0.2%.

[0082] For ease of understanding, Figure 4 A schematic diagram of the composition of four positive power lens groups is given.

[0083] If the embodiment of the present application includes 4 groups of positive focal length lens groups, 4 groups of 12 lenses can be used, and each lens group is coupled with a small pitch, thereby avoiding the attenuation of light caused by the glue layer in the glued lens on the one hand, and improving the flexibility of the solution on the other hand.

[0084] As another optional embodiment, the microscope objective in the embodiment of the present application may also include a combination 102 consisting of 5 groups of positive focal length lens groups. For ease of understanding, Figure 5 A schematic diagram of the composition of 5 groups of positive power lens groups is given, wherein the 5 groups of positive power lens groups include:

[0085] The fifth positive lens group includes a positive lens 6', a negative lens 7' and a positive lens 8' which are coaxially arranged in sequence from the object side to the image side, wherein the focal length of the fifth positive lens group includes [249mm, 259mm].

[0086] The sixth positive lens group includes a positive lens 9' and a negative lens 10' coaxially arranged in sequence from the object side to the image side, wherein the negative lens 10' is closer to the image plane than the positive lens 9', and the focal length of the sixth positive lens group includes [467mm, 477mm].

[0087] The seventh positive lens group includes a positive lens 11 ′, and the focal length of the seventh positive lens group includes [383 mm, 393 mm].

[0088] The eighth positive lens group includes a positive lens 12′ and a negative lens 13′ coaxially arranged in sequence from the object side to the image side, wherein the negative lens 13′ is closer to the image plane than the positive lens 12′, and the focal length of the eighth positive lens group includes [453mm, 463mm].

[0089] The ninth positive lens group comprises a positive lens 14′ and a negative lens 15′ coaxially arranged in sequence from the object side to the image side, wherein the negative lens 15′ is closer to the image plane than the positive lens 14′, and the focal length of the ninth positive lens group comprises [251mm, 351mm].

[0090] The focal length range of the microscope objective lens in the embodiment of the present application includes [8mm, 20mm]. It can be obtained that when 102 includes 5 groups of positive focal power lens groups, the ratio range of the focal length of the 5 groups of positive focal power lens groups to the focal length of the microscope objective lens includes [4, 5].

[0091] In the above five groups of positive focal length lens groups, each lens in each lens group adopts separate small-pitch coupling, wherein the distance d between each coupled lens is greater than 0.1 mm and less than 0.5 mm, thereby avoiding the attenuation of light caused by the use of cemented lenses (because the glue layer of the cemented lens cannot withstand the irradiation of high-power lasers, it is easy to produce attenuation and reduce the transmittance).

[0092] Furthermore, when 102 includes 5 groups of positive focal power lens groups, the microscope objective also includes an aperture arranged between the negative lens 7′ and the positive lens 9′, so that the telecentricity of the entire microscope objective is very high, that is, the image plane incident angle of the main light is less than 0.5°, so that when the microscope objective is used to detect semiconductor defects, the imaging distortion of the defects is less than 0.2%.

[0093] For ease of understanding, Figure 5 A schematic diagram of the composition of 5 positive power lens groups is given. Figure 6 A schematic diagram of the incident angle of the image plane of the principal ray in the embodiment of the present application is given. Figure 6 It can be seen that when an aperture is provided between the negative lens 7' and the positive lens 9', the telecentricity of the entire microscope objective is very high, that is, the incident angle of the main light plane is almost close to 0°, that is, almost parallel to the x-axis.

[0094] If the embodiment of the present application includes 5 groups of positive focal length lens groups, 5 groups of 10 lenses can be used, and each lens group is coupled with a small pitch, thereby avoiding the attenuation of light caused by the glue layer in the glued lens on the one hand, and improving the flexibility of the solution on the other hand.

[0095] based on Figure 1 The embodiment described below Figure 1 The meniscus positive lens group 103 in the embodiment is described in detail:

[0096] As an optional embodiment, the meniscus positive lens group 103 in the embodiment of the present application includes a meniscus positive lens 15, a meniscus positive lens 16 and a meniscus positive lens 17 coaxially arranged in sequence from the object side to the image side, and the concave surfaces of the meniscus positive lens 15, the meniscus positive lens 16 and the meniscus positive lens 17 are all facing the image plane, and the focal length range of the meniscus positive lens group includes [40mm, 50mm]. For ease of understanding, Figure 7 A schematic diagram of a combination including a meniscus positive lens 15, a meniscus positive lens 16 and a meniscus positive lens 17 is given.

[0097] When the meniscus positive lens group 103 includes a lens group consisting of a meniscus positive lens 15, a meniscus positive lens 16 and a meniscus positive lens 17, the ratio range of the focal length of the meniscus lens group to the focal length of the microscope objective lens includes [2.8, 3.5].

[0098] As another optional embodiment, the meniscus lens group 103 in the embodiment of the present application includes a meniscus positive lens 16' and a meniscus positive lens 17' coaxially arranged from the object side to the image side, and the concave surfaces of the meniscus positive lens 16' and the meniscus positive lens 17' are both facing the image plane, and the focal length range of the meniscus positive lens group includes [44mm, 54mm]. For ease of understanding, Figure 8 A schematic diagram of a combination including a meniscus positive lens 16' and a meniscus positive lens 17' is given.

[0099] When the meniscus positive lens group 103 includes a lens group consisting of a meniscus positive lens 16 ′ and a meniscus positive lens 17 ′, the ratio range of the focal length of the meniscus positive lens group to the focal length of the microscope objective lens includes [2.8, 3.5].

[0100] Furthermore, the meniscus positive lens 15, the meniscus positive lens 16 and the meniscus positive lens 17, or the meniscus positive lens 16′ and the meniscus positive lens 17′ in the embodiments of the present application can adopt a Qiming lens group, because the Qiming lens group can make the light converge precisely at one point after refraction, without spherical aberration, coma and astigmatism, that is, the Qiming lens group can eliminate the phase difference of the lens, making the image clearer.

[0101] Furthermore, after adopting the negative focal lens group, 4 or 5 positive focal lens groups and meniscus lens group in the above-mentioned embodiments, the length of the microscope objective lens in the embodiment of the present application is less than 300mm, the field of view of the microscope objective lens is greater than 1.3mm, the resolution is less than 0.3mm, and the working distance of the microscope objective lens is extended to 1.5mm to 2.5mm, avoiding the mutual collision between the object to be detected and the lens, so that the microscope objective lens in the embodiment of the present application can have a large field of view, a large numerical aperture and a high resolution, thereby improving the detection efficiency of the object to be detected on the one hand, and improving the resolution of the object to be detected on the other hand. For easy understanding, Fig. 9 The imaging effect point diagram of the microscope objective lens in the embodiment of the present application is given. Specifically, the point diagram is a point diagram in which, in the imaging process of geometric optics, many light rays emitted from a point are imaged by the optical system. Due to the existence of aberrations, the intersection points of the light rays with the image plane are no longer concentrated at one point, but form a diffuse pattern distributed within a certain range. In the point diagram, the density of these points is used to measure the imaging quality of the optical system. Fig. 9 In the point diagram, the left ordinate represents the size of the field of view and the relative field of view. The RMS point size in the right ordinate is the root mean square of the radial size of the light. The RMS size depends on each light being traced, so it can give a rough idea of ​​the light diffusion. The 100% in the left ordinate, also called the geometric radius (GEO), is the radius of the circle centered at the reference point that surrounds all the intersection points of the light rays. Fig. 9 The medium diffusion patterns are all located within the Airy disk, which shows that the imaging quality of the microscope objective in this application is very good.

[0102] Furthermore, when the microscope objective lens in the embodiment of the present application operates at 266nm±0.02nm, even if the bandwidth is only 0.02nm, chromatic aberration is introduced, thereby reducing the optical resolution. Therefore, the material of each lens in each lens group in the embodiment of the present application adopts a combination of calcium fluoride and fused quartz to correct the chromatic aberration, so that the optical resolution of the microscope objective lens in the embodiment of the present application can reach below 0.3um.

[0103] In addition, the first lens and the last lens in the microscope objective in the embodiment of the present application, that is, the first lens in the negative optical focal length group from the object side to the image side and the last lens in the meniscus lens group, are made of fused quartz, thereby avoiding the atomization of calcium fluoride due to humid air and the problem of reducing the light transmittance of the microscope objective due to the atomization phenomenon.

[0104] Furthermore, the microscope objective lens in the embodiment of the present application can also work at a wavelength of 520nm, because the microscope objective lens in the embodiment of the present application also needs to be combined with a wavelength of 520nm for automatic focusing, and the focal plane of the microscope objective lens in the embodiment of the present application when working at a wavelength of 266nm and when working at a wavelength of 520nm coincides with each other. For ease of understanding, Fig.10 The field curvature curves of the microscope objective lens when it works at 266nm and 520nm are given.

[0105] For ease of understanding, the following takes the microscope objective lens including a combination 101 consisting of two negative lens groups, a combination 102 consisting of five positive focal length lens groups, and a group of meniscus positive lens groups 103 as an example to give the lens parameters of the microscope objective lens in the embodiment of the present application. Fig.11 and Table 1, where Fig.11 A schematic diagram of a microscope objective lens including 8 lens groups and 17 lenses is given. Table 1 gives the radius parameters and thickness parameters of the surface of each lens in the 17 lenses, as well as the material parameters of each lens.

[0106] Specifically, when the microscope objective includes two groups of negative lens groups, namely a first negative lens group and a second negative lens group, the first negative lens group includes: a negative lens 1′, and the second negative lens group includes: a positive lens 2′, a negative lens 3′, a positive lens 4′ and a negative lens 5′ coaxially arranged in sequence from the object side to the image side.

[0107] When the microscope objective includes 5 groups of positive focal power lens groups, they are the fifth positive lens group, including a positive lens 6', a negative lens 7' and a positive lens 8' coaxially arranged in sequence from the object side to the image side, wherein the focal length of the fifth positive lens group includes [249mm, 259mm].

[0108] The sixth positive lens group includes a positive lens 9' and a negative lens 10' coaxially arranged in sequence from the object side to the image side, wherein the negative lens 10' is closer to the image plane than the positive lens 9', and the focal length of the sixth positive lens group includes [467mm, 477mm].

[0109] The seventh positive lens group includes a positive lens 11 ′, and the focal length of the seventh positive lens group includes [383 mm, 393 mm].

[0110] The eighth positive lens group includes a positive lens 12' and a negative lens 13', wherein the negative lens 13' is closer to the image plane than the positive lens 12', and the focal length of the eighth positive lens group includes [453mm, 463mm].

[0111] The ninth positive lens group includes a positive lens 14 ′ and a negative lens 15 ′, wherein the negative lens 15 ′ is closer to the image plane than the positive lens 14 ′, and the focal length of the ninth positive lens group includes [251 mm, 351 mm].

[0112] The meniscus lens group comprises: a meniscus positive lens 16' and a meniscus positive lens 17' which are coaxially arranged in sequence from the object side to the image side.

[0113] Table 1

[0114]

[0115]

[0116] An embodiment of the present application also provides a detection system, including a light source, an illumination lens group, a microscope objective lens, an imaging lens group and a detector, wherein: the light source is used to emit a light beam to an object to be detected; the illumination lens group is used to shape the light beam emitted by the light source; the microscope objective lens is used to magnify the features in the object to be detected; the imaging lens group is used to image the features in the magnified object to be detected; and the detector is used to photograph the features in the magnified object to be detected.

[0117] The description of the specific components of the microscope objective in the detection system is similar to Figures 1 to 11 The description is similar to that in , and will not be repeated here.

[0118] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A microscope objective lens, It is characterized in that include: At least one negative power lens group, four or five positive power lens groups and one meniscus positive lens group are coaxially arranged in sequence from the object side to the image side, wherein the working band of the microscope objective lens includes [266nm, 520nm], and the numerical aperture of the microscope objective lens is greater than 0.85; Wherein, the ratio of the focal length of the at least one group of negative focal power lens groups to the focal length of the microscope objective lens includes [-5, -2.5]; The ratio of the focal length of the four or five positive power lens groups to the focal length of the microscope objective lens includes [4, 16]; The ratio of the focal length of the meniscus positive lens group to the focal length of the microscope objective lens ranges from [2.8, 3.5], wherein the concave surfaces of the meniscus positive lens group all face the image plane.

2. The microscope objective lens according to claim 1, It is characterized in that The at least one negative power lens group comprises: A negative lens group, or two negative lens groups; The negative lens group comprises a negative lens 1 and a negative lens 2 coaxially arranged in sequence from the object side to the image side, and the focal length range of the negative lens group comprises [-66mm, -56mm]; The two negative lens groups include a first negative lens group and a second negative lens group, the first negative lens group includes a negative lens 1′, the second negative lens group includes a positive lens 2′, a negative lens 3′, a positive lens 4′ and a negative lens 5′ coaxially arranged in sequence from the object side to the image side, the focal length range of the first negative lens group includes [-51mm, -61mm], and the focal length range of the second negative lens group includes [-763mm, -753mm].

3. The microscope objective lens according to claim 1, It is characterized in that The four positive power lens groups include: a first positive lens group, a second positive lens group, a third positive lens group and a fourth positive lens group which are coaxially arranged in sequence from the object side to the image side, wherein: The first positive lens group comprises a positive lens 3, a negative lens 4 and a positive lens 5 which are coaxially arranged in sequence from the object side to the image side, wherein the focal length of the first positive lens group comprises [360 mm, 370 mm]; The second positive lens group includes a positive lens 6, a negative lens 7, a positive lens 8, a negative lens 9 and a positive lens 10 coaxially arranged in sequence from the object side to the image side, and the focal length of the second positive lens group includes [143mm, 153mm]; The third positive lens group comprises a negative lens 11 and a positive lens 12 coaxially arranged in sequence from the object side to the image side, wherein the negative lens 11 is farther away from the image plane than the positive lens 12, and the focal length of the third positive lens group comprises [442mm, 452mm]; The fourth positive lens group includes a negative lens 13 and a positive lens 14 coaxially arranged in sequence from the object side to the image side, wherein the negative lens 13 is farther away from the image plane than the positive lens 14, and the focal length of the fourth positive lens group includes [1461mm, 1471mm].

4. The microscope objective lens according to claim 1, It is characterized in that The five positive power lens groups include: a fifth positive lens group, a sixth positive lens group, a seventh positive lens group, an eighth positive lens group and a ninth positive lens group, which are coaxially arranged in sequence from the object side to the image side, wherein: The fifth positive lens group comprises a positive lens 6', a negative lens 7' and a positive lens 8' which are coaxially arranged in sequence from the object side to the image side, wherein the focal length of the fifth positive lens group comprises [249mm, 259mm]; The sixth positive lens group comprises a positive lens 9′ and a negative lens 10′ coaxially arranged in sequence from the object side to the image side, wherein the negative lens 10′ is closer to the image plane than the positive lens 9′, and the focal length of the sixth positive lens group comprises [467 mm, 477 mm]; The seventh positive lens group includes a positive lens 11′, and the focal length of the seventh positive lens group includes [383mm, 393mm]; The eighth positive lens group includes a positive lens 12′ and a negative lens 13′, wherein the negative lens 13′ is closer to the image plane than the positive lens 12′, and the focal length of the eighth positive lens group includes [453 mm, 463 mm]; The ninth positive lens group includes a positive lens 14 ′ and a negative lens 15 ′, wherein the negative lens 15 ′ is closer to the image plane than the positive lens 14 ′, and the focal length of the ninth positive lens group includes [251 mm, 351 mm].

5. The microscope objective according to claim 3 or 4, It is characterized in that The coupling spacing between each lens in each positive lens group is d, wherein 0.1 mm≤d≤0.5 mm.

6. The microscope objective according to claim 3 or 4, It is characterized in that If the microscope objective lens includes four groups of positive power lenses, the microscope objective lens further includes an aperture stop disposed between the negative lens 7 and the negative lens 9; If the microscope objective includes five groups of positive power lenses, the microscope objective further includes an aperture stop arranged between the negative lens 7 ′ and the positive lens 9 ′.

7. The microscope objective lens according to claim 6, It is characterized in that The image plane incident angle of the principal light in the microscope objective is less than or equal to 0.5°.

8. The microscope objective lens according to claim 1, It is characterized in that The group of meniscus positive lens comprises: A meniscus positive lens 15, a meniscus positive lens 16 and a meniscus positive lens 17 are coaxially arranged in sequence from the object side to the image side, and the focal length range of the meniscus lens group composed of the meniscus positive lens 15, the meniscus positive lens 16 and the meniscus positive lens 17 includes [40mm, 50mm]; or; The meniscus positive lens 16' and the meniscus positive lens 17' are coaxially arranged in sequence from the object side to the image side, and the focal length range of the meniscus lens group composed of the meniscus positive lens 16' and the meniscus positive lens 17' includes [44mm, 54mm].

9. The microscope objective lens according to claim 1, It is characterized in that The meniscus positive lens group includes a Qiming lens group.

10. The microscope objective according to any one of claims 1 to 9, It is characterized in that The focal length range of the microscope objective lens includes [8mm, 20mm], and the length of the microscope objective lens is less than 300mm.

11. The microscope objective according to claim 10, It is characterized in that The field of view of the microscope objective lens is greater than 1.3 mm, and / or the optical resolution of the microscope objective lens is less than 0.3 um.

12. The microscope objective according to claim 10, It is characterized in that The working distance of the microscope objective lens includes 1.5 mm to 2.5 mm.

13. The microscope objective according to claim 10, It is characterized in that The working band of the microscope objective lens also includes 520 nm, and the focal plane of the microscope objective lens when the working band is 266 nm coincides with the focal plane of the microscope objective lens when the working band is 520 nm.

14. The microscope objective according to any one of claims 1 to 9, It is characterized in that The material of the lens close to the object side in the at least one negative power lens group is fused quartz, and the material of the lens close to the image side in the meniscus positive lens group is fused quartz.

15. A detection system, It is characterized in that include: A light source, an illumination lens assembly, a microscope objective lens, an imaging lens assembly and a detector according to any one of claims 1 to 14, wherein: The light source is used to emit a light beam to the object to be detected; The lighting mirror assembly is used to shape the light beam emitted by the light source; The microscope objective lens is used to magnify the features in the object to be detected; The imaging lens assembly is used to image the features of the magnified object to be detected; The detector is used to photograph the features in the magnified object to be detected.

Images