Optical assembly and detection device

Abstract

The embodiment of the invention provides an optical assembly and a detection device with the same, the optical assembly comprises a first lens group and a second lens group which are sequentially arranged along a collimation light path direction, the focal power # imgabs0 # of the first lens group is a negative value, the focal power # imgabs1 # of the second lens group is a positive value, and the focal power # imgabs0 # of the second lens group is a positive value. The # imgabs2 first lens group comprises a first lens with positive focal power, a second lens with negative focal power and a third lens with positive focal power, and certain intervals are formed among the first lens, the second lens and the third lens. The collimation light path direction is the direction from the light source to the to-be-detected object, so that large-angle light collection is realized, aberration correction is facilitated, the problem that an existing light path system is difficult to realize light beam collimation, effective collection of large-angle light and aberration correction at the same time is solved, and the detection accuracy is improved. And the compactness of the system is improved, and the manufacturing cost is reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of optical technology, and in particular, to an optical component and a detection device having the same. Background Art

[0002] The field of wafer defect detection (hereinafter referred to as wafer detection) mainly covers three major methods: appearance detection, electron beam detection and optical detection. Among them, optical detection technology, with its non-contact measurement, high-resolution imaging and wide applicability, has shown great potential in wafer surface quality assessment, optical property analysis and microstructure detection, and has become the focus of industry attention.

[0003] Wafer inspection, especially when using an interferometer, requires not only to irradiate a highly parallel collimated light beam onto the wafer surface, but also to collect the light to be detected that reflects the surface performance of the wafer. In particular, since the wafer has a certain degree of warpage, the incident angle of the light to be detected that needs to be collected is relatively large (hereinafter referred to as large-angle light collection). In order to obtain high-precision detection results, it is particularly important to collect these large-angle lights. In addition, the working wavelength needs to cover visible light to infrared light to broaden the detection range.

[0004] However, wavelengths of different bands will produce significant chromatic aberration during transmission, which poses a challenge to detection accuracy. Existing optical path systems often have difficulty in effectively collecting large-angle light while obtaining a collimated beam, and have certain deficiencies in chromatic aberration correction. Summary of the invention

[0005] In view of this, the present disclosure provides an optical component and a detection device having the same, aiming to solve the problem that the existing optical path system is difficult to simultaneously achieve collimated light beams, effectively collect large-angle light, and correct chromatic aberration.

[0006] In one aspect, the optical assembly provided by the present disclosure comprises a first lens group and a second lens group arranged in sequence along a collimated optical path, wherein the optical power of the first lens group is is a negative value, the focal length of the second lens group is a positive value, The distance L between the first lens group and the second lens group satisfies: The first lens group includes a first lens with positive optical power, a second lens with negative optical power and a third lens with positive optical power, and there is a certain interval between the first lens, the second lens and the third lens.

[0007] First, since the total focal length of the optical component is positive and the second lens group bears a larger focal length, this means that the optical component can effectively change the propagation direction of the light, which is conducive to converging and correcting the divergent light from the light source into a parallel light beam. Secondly, with this design, the collected light to be detected is first converged by the positive lens group and then diverged by the negative lens group, so that the main surface formed by the reverse extension line of the light to be detected is pushed outside the optical component (i.e., the right side of the second lens group), which helps to improve the compactness of the structure of the optical component. Thirdly, the interval L between the lens groups can be adjusted according to the system size requirements to improve the flexibility of the use of the optical component. Finally, the first lens group forms a classic Cooke three-piece lens with positive, negative and positive focal lengths, respectively. This roughly symmetrical focal length matching design is not only simple in structure, but also helps to collect large-angle light, and the asymmetric aberrations (such as coma, astigmatism, chromatic aberration, etc.) generated are not large, and the image quality is better.

[0008] On the other hand, the present disclosure provides a detection device, which includes the above-mentioned optical component, light source, optical path system and sensor. The optical component is located between the light source and the object to be detected, so that the light of the light source generates a collimated light beam after passing through the optical component, and the collimated light beam generates a light signal to be detected after irradiating the object to be detected, and the light signal to be detected passes through the optical component again, and is transmitted through the optical path system and received by the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and should not be viewed as limiting the scope.

[0010] It should be understood that the same or similar reference numerals are used in the drawings to indicate the same or similar elements.

[0011] It should be understood that the drawings are merely schematic and that the sizes and proportions of elements in the drawings are not necessarily accurate.

[0012] Figure 1 A schematic diagram of the structure of an optical component provided in one embodiment of the present disclosure.

[0013] Figure 2 for Figure 1 The light path diagram used as the collimated light path.

[0014] Figure 3 for Figure 1 The light path diagram used as the collecting light path.

[0015] Figure 4 A schematic structural diagram of a first lens group provided in one embodiment of the present disclosure.

[0016] Figure 5 A schematic structural diagram of a second lens group provided in one embodiment of the present disclosure.

[0017] Figure 6 A schematic diagram of the structure of an optical component provided in one embodiment of the present disclosure.

[0018] Figure 7 Based on Figure 6 Wavefront aberration plots of collimated beams obtained with the provided optical assembly.

[0019] Figure 8 Based on Figure 6 Provides plots of the deviation from parallelism of a collimated beam obtained with the optical assembly.

[0020] Fig. 9 1 is a wavefront aberration diagram of a collimated light beam obtained by using the optical assembly provided in Comparative Example 1.

[0021] Fig.10 Graph showing the parallelism deviation of a collimated light beam obtained using the optical assembly provided in Comparative Example 1.

[0022] Fig.11 The wavefront aberration diagram of the collimated light beam obtained according to the optical component provided in Comparative Example 2.

[0023] Fig.12 The parallelism deviation diagram of the collimated light beam obtained by the optical assembly provided in Comparative Example 2 is shown.

[0024] Fig.13 Based on Figure 6 Provides a diffuse pattern of light collected by an optical assembly.

[0025] Fig.14 Based on Figure 6 Provides a plot of the wavefront error of the light collected by the optical assembly.

[0026] Fig.15 A schematic diagram of the structure of a detection device provided in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] For optical detection, it is first necessary to provide a collimated light beam to illuminate the object to be detected (such as a wafer) to obtain the light to be detected, such as reflected light, transmitted light, interference light, etc. Taking interference light detection as an example, it can be achieved by a Fizeau or Twyman Green laser interferometer system. Secondly, it is necessary to collect as much light as possible to be detected for subsequent imaging or other processing. Especially for large-size and high-precision detection (such as wafers), due to the existence of warpage, the incident angle of the light to be detected is usually large, and the large-caliber detection object will also bring greater aberrations. When designing the optical path, common optical components such as interference detection optical components usually have an angle of only ±0.1° to collect the detection light while realizing the collimated light beam, which is very small. This is conducive to avoiding obvious aberrations (such as paraxial aberrations), chromatic aberrations or uneven light intensity distribution during the propagation of light. If it is necessary to collect large-angle light (i.e., light with a large incident angle), it is necessary to add more optical elements to deal with various aberrations (such as off-axis aberrations, large apertures) caused by large-angle light to keep the imaging quality unaffected. Thirdly, the working wavelength of common optical components mostly works in the 633nm band. For large-sized detection objects, in order to increase the detection range, the working wavelength needs to cover multiple wavelengths from visible light to infrared light. Multiple wavelengths will cause chromatic aberration during the propagation process, seriously affecting the quality of the collected light.

[0028] In view of this, an embodiment of the present disclosure provides an optical component and a detection device having the same. Compared with the traditional optical component, the optical component provided by the present disclosure uses two lens groups, and the optical power of the first lens group is is a negative value, the focal length of the second lens group is a positive value, and To obtain a collimated light beam, and the second lens group provides a larger optical focal length, which is beneficial to improving the compactness of the optical component structure, wherein the first lens group includes a first lens with a positive optical focal length, a second lens with a negative optical focal length, and a third lens with a positive optical focal length in sequence along the collimated light path direction, so as to realize the collection of large-angle light and facilitate the correction of aberrations. In this way, it not only helps to solve the problem that the existing optical path system is difficult to simultaneously realize a collimated light beam, effectively collect large-angle light, and correct chromatic aberration, but also helps to improve the compactness of the system and reduce manufacturing costs.

[0029] For ease of understanding, the optical assembly 10 provided by the embodiment of the present disclosure is exemplified below in conjunction with specific embodiments and accompanying drawings. It should be understood that the present disclosure can be implemented in a variety of ways and should not be construed as being limited to the embodiments described herein, which are only provided for a more thorough and clear understanding of the present disclosure.

[0030] An embodiment of the present disclosure provides an optical component 10. The optical component 10 can be used as a collimating component to provide a collimated light beam (refer to Figure 2 ), can also be used as a light collection component (see Figure 3 ) is used to collect the light to be detected, and can also be used as a collimator and light collection component (reference Figure 6 For ease of understanding, the overall structure of the optical component 10 is first described below by way of example.

[0031] Combination Figure 1 and Figure 2 , the optical assembly 10 may include a first lens group 100 and a second lens group 200 arranged in sequence along the direction of the collimated light path 10a. The collimated light path 10a is the optical assembly 10 as a collimated assembly, which is used to provide a collimated light beam to illuminate the object to be detected 300 to obtain the light to be detected. Therefore, the direction of the collimated light path 10a is along the direction of the arrow (i.e., the x-axis) in the figure, specifically, along the direction of the light source S propagating to the object to be detected, that is, after the light of the light source passes through the first lens group 100 and the second lens group 200, a parallel light beam is obtained at the exit position of the second lens group 200 (i.e., the right side).

[0032] Refractive power of the first lens group It is a negative value, which is mainly used to correct the high-order aberrations and off-axis aberrations of optical components (such as fifth-order aberrations, seventh-order aberrations and aberrations of off-axis large-angle light). The focal length of the second lens group It is a positive value, which is mainly used to correct the primary aberration and paraxial aberration of optical components (such as third-order aberration and aberration of paraxial small-angle and large-aperture light). Wherein, the focal length of the first lens group 100 is less than -1*10 4 mm, the focal length of the second lens group 200 is greater than 1*10 3 mm. In this way, a larger focal length is conducive to reducing the tolerance requirements of optical processing and assembly.

[0033] Since the total focal length of the optical component is positive and the second lens group bears a larger focal length, this means that the optical component can quickly change the propagation direction of the light, which is conducive to focusing and correcting the light from the light source into a parallel light beam. In addition, with this design, the collected light to be detected is first converged by the positive lens group and then diverged by the negative lens group, so that the main surface formed by the reverse extension line of the light to be detected is pushed outside the optical component (away from the light source direction, that is, to the right of the second lens group), which helps to improve the compactness of the structure of the optical component.

[0034] It should be noted that the interval L between the first lens group 100 and the second lens group 200 is not specifically limited. Preferably, L can satisfy: If the interval L between the first lens group 100 and the second lens group 200 is less than The size of the optical component becomes larger. If the interval L between the first lens group 100 and the second lens group 200 is greater than Although the size of the optical components is reduced, it is difficult to completely eliminate the aberration correction, and the image quality is significantly deteriorated. For example, the interval L can be There is no specific limitation here, and it can be selected according to the actual needs of the optical component. In this way, the interval L between the lens groups can be adjusted according to the system size requirements, thereby improving the flexibility of the use of the optical component.

[0035] It is worth noting that the focal length of the first lens group is The optical power of the second lens group The absolute value of is not specifically limited. In order to obtain high-quality image quality, preferably, If the ratio of the focal length is greater than 19, it is difficult to completely eliminate the off-axis aberration, on-axis aberration and aberration caused by large-angle light in the two lens groups, and the image quality will be significantly deteriorated. If the ratio of the focal length is less than 15, the tolerance performance of the optical components will be significantly deteriorated, and the difficulty of optical component processing and assembly adjustment of the first lens group will be significantly increased. For example, It can be 16, 16.5, 17, 17.5 and 18, and there is no specific limitation here.

[0036] Combination Figure 1 and Figure 3 The first lens group 100 includes optical powers in sequence along the collimated optical path: The first lens 110 has a positive focal length of The second lens 120 has a negative optical power. The third lens 130 has a positive value. Figure 3 The optical component 10 is used as a light collecting component to collect light, such as collecting light to be detected, and obtaining its characteristic parameters through the light to be detected, such as morphology, thickness, warpage, etc. The light to be detected located on the right side of the second lens group 200 forms more convergent light after passing through the second lens group 200 and the first lens group 100, and is received by other subsequent systems, such as an optical path system or a detection system. Therefore, the direction of light propagation in the light collection optical path 10b is opposite to the direction of light propagation in the collimated optical path 10a to achieve optical path multiplexing. Of course, it can also be used alone as a light collection optical path or a collimated optical path. In addition, the first lens and the third lens with positive optical power can mainly provide correction of negative high-order aberrations, and the second lens with negative optical power can mainly provide correction of positive high-order aberrations.

[0037] It is worth noting that the first lens group forms a classic Cooke three-piece lens with positive, negative and positive optical powers. This roughly symmetrical optical power matching design is not only simple in structure, but also helps to collect large-angle light, and the asymmetric aberrations (such as coma, astigmatism, chromatic aberration, etc.) generated are not large, and the image quality is good. Moreover, the numerical aperture of this structure is 0.2 to 0.25, which helps to further improve the ability to collect light compared to the numerical aperture of traditional optical components of only 0.1. In addition, this structure is the simplest lens combination that can correct all aberrations. By designing the radii of the six spherical surfaces of the three lenses and the two air gaps respectively, all aberrations can be corrected and high-precision light can be obtained, which is conducive to providing the possibility for subsequent imaging or detection.

[0038] In order to further correct the off-axis aberrations caused by the propagation of large-angle light, such as off-axis coma and spherical aberration, refer to Figure 3 and Figure 4 , the first lens 110 may include a first side surface 111 away from the second lens group 300 and a second side surface 113 facing the object to be detected 300, the bending directions of the first side surface 111 and the second side surface 113 are both toward the object to be detected, the second lens 120 may include a third side surface 121 away from the second lens group and a fourth side surface 123 close to the object to be detected, the bending direction of the third side surface 121 is opposite to the bending direction of the fourth side surface 123, the third lens 130 may include a fifth side surface 131 away from the second lens group and a sixth side surface 133 close to the object to be detected, the fifth side surface is a plane, and the bending direction of the sixth side surface 133 is toward the object to be detected. In this way, if used as a collimated light path 10a, the light of the light source passes through the first side surface 111, the second side surface 113, the third side surface 121, the fourth side surface 123, the fifth side surface 131 and the sixth side surface 133 in sequence. If used as a light collecting light path 10b, the propagation direction of the light to be detected is opposite to the above.

[0039] This curved design is conducive to making the aberration values ​​of each optical surface offset each other, thereby reducing high-order aberrations. For example, the first lens and the third lens can mainly contribute to negative third-order coma and third-order spherical aberration, and the second lens can mainly contribute to positive third-order and fifth-order coma and third-order and fifth-order spherical aberration. In addition, this combination can also reduce off-axis aberrations by changing the direction of the incident light. For example, after the light to be detected passes through the third lens, the second lens and the first lens in turn, it is converged, diverged and converged again, thereby changing the incident angle of the light to reduce off-axis aberrations.

[0040] In addition, since the bending directions of the first lens and the third lens are substantially consistent, the first lens group forms such a substantially symmetrical structure. At the same time, the third lens is conducive to sharing the curvature radius with the first lens, thereby reducing the difficulty of the optical element manufacturing process, reducing the difficulty of component assembly and adjustment, and assisting in the correction of primary spherical aberration and chromatic aberration. In addition, it also avoids the problem of insufficient aberration correction caused by only one positive and one negative lens, which is conducive to further improving the ability to correct distortion and field curvature.

[0041] As a specific example, combining Figure 2 and Figure 4 The first side surface 111 may be a spherical surface with a curvature radius R 11 Comply with -1990mm<R 11 <-1970mm, used to receive light from the light source. Preferably, -1985mm≤R 11 ≤-1975mm. For example, R 11 The second side surface 113 may be a spherical surface with a curvature radius R 12 Comply with -211mm<R 12 <-201mm, preferably, -209mm≤R 12 ≤-203mm. For example, R 12 The third side surface 121 may be a spherical surface with a curvature radius R 21 Comply with -247mm<R 21 <-237mm, preferably, -244mm≤R 21 ≤-240mm. For example, R 21 The fourth side surface 123 may be a spherical surface with a curvature radius R 22 Comply with 693mm<R 22 <708mm, preferably, 688mm≤R 22 ≤703mm, for example, R 22 The sixth side surface 133 may be a spherical surface with a curvature radius R 32 Comply with -188mm<R 32 <-182mm, preferably, -186≤R 32 ≤-184mm. For example, R 32 It can be -186mm, -185mm, or -184mm, and there is no specific limitation here.

[0042] The combination of the bending direction and curvature radius of the three lenses can help further correct the aberrations and chromatic aberrations of most of the Seidel images caused by the off-axis large-angle collection of the light beam, as well as a small number of near-axis Seidel aberrations (mainly including spherical aberration, coma, astigmatism, and distortion), thereby helping to ensure that the imaging quality is close to the diffraction limit, providing the premise for subsequent high-quality imaging and precise detection.

[0043] It should be noted that, for the curvature radius of each lens in the optical assembly, curvature to the left is positive, and curvature to the right is negative.

[0044] It should be noted that the central material thickness d1 between the first side surface 111 and the second side surface 113 of the first lens 110 along the main axis direction satisfies 19.8mm<d1<20.2mm, preferably, 19.9mm≤d1≤20.1mm, for example, d1 can be 19.9mm, 20mm and 20.1mm, which is not specifically limited here. The central material thickness d2 between the third side surface 121 and the fourth side surface 123 of the second lens 120 along the main axis direction satisfies 12.1mm<d2<12.3mm, preferably, 12.15mm≤d2≤12.25mm, for example, d2 can be 12.15mm, 12.2mm and 12.25mm, which is not specifically limited here. The central material thickness d3 between the fifth side surface 131 and the sixth side surface 133 of the third lens 130 along the principal axis direction satisfies 21.8 mm<d3<22.2 mm. Preferably, 21.9 mm≤d3≤22.1 mm. For example, d3 can be 21.9 mm, 22 mm and 22.1 mm, which is not specifically limited here.

[0045] By accurately controlling the thickness of each lens in the first lens group, it is beneficial to accurately control the propagation state of the collimated light beam or the collected light, and to correct the spherical aberration and aberration. In addition, by coordinating the thickness with the bending direction and the radius of curvature, the accurate parameters of each lens can be obtained more accurately, so as to simulate the quality of the image after passing through the first lens group, so as to ensure that the image quality of the entire optical component can be close to the diffraction limit, thus providing a prerequisite for subsequent imaging and precise detection.

[0046] It is worth noting that the central air gap L12 between the second side surface 113 and the third side surface 121 along the main axis direction satisfies 0.9mm<L12<1.1mm, preferably, 0.95mm≤L12≤1.05mm, for example, L12 can be 0.95mm, 1mm and 1.05mm, which is not specifically limited here. The central air gap L23 between the fourth side surface 123 and the fifth side surface 131 along the main axis direction, and 7.8mm<L23<8.2mm, preferably, 7.9mm≤L23≤8.1mm, for example, L23 can be 7.9mm, 8mm and 8.1mm, which is not specifically limited here.

[0047] By accurately designing the spacing of each lens, it is helpful to further improve the imaging quality. In addition, by coordinating the spacing with the bending direction, radius of curvature and thickness, it is helpful to further obtain the accurate parameters of each lens, and correct most of the aberrations and chromatic aberrations of the off-axis large-angle collection beam, as well as the paraxial aberrations (mainly including spherical aberration, coma, astigmatism, and distortion).

[0048] In order to correct the chromatic aberration caused by multiple wavelengths, the Abbe number of the first lens 110 can be greater than 60, and preferably, it can be made of a meniscus crown material. The Abbe number of the second lens 120 can be greater than 30 and less than 50, and preferably, it can be made of a double concave heavy flint material. The Abbe number of the third lens 130 is greater than 60, and preferably, it can be made of a plano-convex crown material.

[0049] Since the larger the Abbe number, the smaller the difference in refractive index for different wavelengths, the greater the ability of the first lens and the third lens to compensate for dispersion, and the smaller the ability of the second lens to compensate for dispersion. Therefore, according to the use of working wavelengths (visible light, such as 633nm, near infrared, such as 808nm, 852nm, 880nm), lenses with different Abbe numbers are used to compensate and cooperate with each other to reduce the difference in refractive index of different wavelengths, so as to eliminate the chromatic aberration caused by different wavelengths.

[0050] To further correct the chromatic aberration caused by multiple wavelengths, continue to refer to Figure 3 and Figure 4 , the optical power of the first lens 110 satisfy: Preferably, For example The optical power of the second lens 120 may be 0.00246, 0.00248, 0.00250, 0.00252, and 0.00254, which are not specifically limited here. satisfy: Preferably, For example The focal length of the third lens 130 may be -0.00557, -0.00554, -0.00551, and -0.00547, which are not specifically limited here. satisfy: Preferably, For example It can be 0.00273, 0.00274, 0.00275, 0.00276 and 0.00277, and is not specifically limited here.

[0051] Since the adjustment of the optical focal length can change the focusing position of light of different wavelengths, according to the use of the working wavelength, the optical focal length corresponding to the wavelengths from visible light to near-infrared is selected for adjustment, which helps to achieve that different wavelengths are focused on the same position.

[0052] The combination of materials and the optical power of the first lens group can help further correct chromatic aberration, which ensures that the quality of light collection at multiple working wavelengths is not affected, thereby ensuring imaging quality and providing possibilities for subsequent imaging and precision measurement.

[0053] It should be noted that if the light source is a point light source, for the collimated light path 10a, it is usually necessary to filter the collimated light source, and then collimate the point light source through the collimated light path. In this way, the nonlinear error of the obtained parallel light is large, and the signal-to-noise ratio is low, which makes the accuracy and precision of the light to be detected after subsequent irradiation to the object to be detected significantly reduced, which is not conducive to high-precision imaging and detection. For this reason, the light source disclosed in the present invention adopts an extended light source with a size greater than 10mm, which helps to improve the detection capability and signal-to-noise ratio of the collimated light beam, and thus helps to improve the accuracy and precision of the detection.

[0054] In order to further improve the parallelism of the collimated beam and reduce the aberration of the paraxial light caused by the extended light source, refer to Figure 3 and Figure 5 The second lens group 200 may include a fourth lens 210 and a fifth lens 220 for correcting paraxial aberrations.

[0055] Specifically, the fourth lens 210 may have a seventh side surface 211 facing the first lens group 100 and an eighth side surface 213 away from the first lens group (facing the object to be detected), the seventh side surface 211 is a plane, and the curvature direction of the eighth side surface 213 faces the object to be detected 300. Such a design is conducive to providing negative primary coma and spherical aberration.

[0056] It should be noted that the diameter of the fourth lens 210 is larger than the size of the object to be detected, for example, the size of the fourth lens is larger than the wafer diameter, which is conducive to covering the large-diameter collimated light beam to the wafer surface and collecting the light to be detected reflected from the wafer surface or the lens. Preferably, the diameter of the second lens group is greater than or equal to 1.05 times the wafer size and less than or equal to 1.1 times the wafer size. In this way, the second lens group will not be too large, which is conducive to reducing costs, and is conducive to collecting the light to be detected and improving the collection effect.

[0057] It is worth noting that the curvature radius R of the eighth side surface 213 is 42 Can meet -796mm<R 42 <-782mm. Preferably, -792mm≤R 42 ≤-786mm, for example R 42 It can be -792mm, -790mm, -789mm and -786mm, which is not specifically limited here. At the same time, the central material thickness d4 between the seventh side 211 and the eighth side 213 along the main axis direction meets 37.8mm<d4<38.2mm, preferably 37.9mm≤d4≤38.1mm, for example, d4 can be 37.9mm, 38mm and 38.1mm, which is not specifically limited here. In this way, it is conducive to the correction of third-order coma and third-order spherical aberration.

[0058] Continue to refer Figure 3 and Figure 5 The fifth lens 220 may include a ninth side surface 221 facing the first lens group and a tenth side surface 223 facing the object to be detected, the ninth side surface is a plane 221, and the curvature direction of the tenth side surface 223 faces the first lens group. The fifth lens with a negative optical power helps to provide positive coma and spherical aberration.

[0059] It is worth noting that the curvature radius R of the ninth side surface 221 is 52 Comply with 1790mm<R 52 <1810mm, preferably, 1795mm≤R 52 ≤1805mm, for example R 52 At the same time, the central material thickness d5 between the ninth side surface 221 and the tenth side surface 223 along the main axis direction meets 21.8mm<d5<22.2mm, preferably 21.9mm≤d5≤22.1mm, for example, d5 can be 21.9mm, 22mm and 22.1mm, which is not specifically limited here.

[0060] For large-diameter objects to be inspected, there will be a lot of aberrations and spherical aberrations (the larger the diameter, the more aberrations and spherical aberrations will increase in square and cube). The coordination of the bending direction and curvature radius of the fourth and fifth lenses is conducive to the correction of most of the Seeder aberrations of large-diameter paraxial beams. Moreover, compared with the existing expensive aspheric lenses, this combination not only has a better overall correction effect, especially more effective correction of off-axis light, but also helps to further reduce costs.

[0061] It should be noted that the optical power of the fourth lens 210 is Can satisfy: Refractive power of the fifth lens 220 Can meet Preferably, For example It can be -0.000283, -0.000285 and -0.000287, and is not specifically limited here.

[0062] It should also be noted that the materials of the fourth lens 210 and the fifth lens 220 are not specifically limited, and preferably, they can be plano-convex quartz materials or crown materials, and the fifth lens 220 can be plano-concave quartz materials or crown materials. This helps to further reduce manufacturing costs.

[0063] Exemplarily, the central air gap between the seventh side 211 and the tenth side 223 along the main axis direction is L45, and 10.5mm<L45<11.5mm, preferably, 10.8mm≤L45≤11.2mm, for example, L45 can be 10.8mm, 11mm and 11.2mm, which is not specifically limited here.

[0064] The combination of the fourth lens and the fifth lens is advantageous for correcting most of the aberrations caused by the large-aperture paraxial light beam, and the manufacturing cost is greatly reduced.

[0065] According to the optical path design and material matching of the above two sets of five-pieces, the wavefront error of the collimated light beam emitted by the light source after passing through the optical components is analyzed (reference Figure 7 ) and parallelism (reference Figure 8 ), and the diffuse pattern as a light collecting component (reference Fig.13 ) and wavefront error diagram (reference Fig.14 ).

[0066] 1.Reference Figure 7, calculated by optical analysis software, the maximum value of the wavefront error of the collimated light beam emitted by the light source (780nm~900nm) after passing through the first lens group and the second lens group is 0.0658λ, the minimum value is 0.0653λ, and the average error value is 0.0655λ. The ideal situation is that the wavefront distortion is less than 0.07λ. Therefore, the aberration generated by the optical component provided by the present disclosure as a collimated light path can be almost ignored, which makes it possible to perform subsequent imaging and high-precision detection. The optical analysis software can be Zemax, CODE V, FRED, OptiFDTD, etc., which are not specifically limited here.

[0067] 2.Reference Figure 8 , calculated by optical analysis software, the maximum deviation of the wavefront parallelism of the collimated light beam emitted by the light source (780nm~900nm) after passing through the first lens group and the second lens group is 4.9501 microradians, the minimum is 4.8787 microradians, and the average deviation is 4.8973 microradians, all better than 5 microradians. It can be seen that the collimated light beam has excellent collimation characteristics.

[0068] 3.Reference Fig.13 , calculated by optical analysis software, after the collimated light beam emitted by the light source (780nm~900nm) passes through the first lens group and the second lens group and irradiates the surface of the object to be detected (wafer), the collected angle of the light to be detected is ±1.5°, and under different collection angles, the image quality near the center area is close to the diffraction limit, the correction effect is very good, and the image quality from the middle to the edge is not bad. The remaining small amount of off-axis aberration can be further eliminated by subsequent detection optical components.

[0069] 4.Reference Fig.14 , calculated by optical analysis software, after the collimated light beam emitted by the light source (780nm~900nm) passes through the first lens group and the second lens group and irradiates the surface of the object to be detected (wafer), the collected angle of the light to be detected is ±1.5° (compared to the traditional incident light angle of ±0.1°), and under different collection angles, the maximum error value is 0.46517λ, the minimum value is 0.08952λ, and the average error value is 0.32037λ.

[0070] <Comparative Example 1>

[0071] refer to Fig. 9 and Fig.10 , the curvature radius of the second side surface 113 of the first lens 110 is designed to be R 12=-190mm. Through optical analysis software simulation, it is found that the maximum wavefront error of the collimated light beam emitted by the light source (780nm~900nm) after passing through the first lens group and the second lens group is 0.19685λ, the minimum is 0.18551λ, and the average error is 0.19038λ. At the same time, the maximum deviation of the wavefront parallelism of the collimated light beam emitted by the light source (780nm~900nm) after passing through the first lens group and the second lens group is 19.677 microradians, the minimum is 15.933 microradians, and the average deviation is 18.024 microradians.

[0072] Through Figure 7 and Figure 8 By comparison, the imaging quality of the collimated beam deteriorates significantly, with the wave image deteriorating by three times and the parallelism deteriorating by four times.

[0073] Comparative Example 2

[0074] refer to Fig.11 and Fig.12 , the central air gap between the seventh side of the fourth lens and the ninth side of the fifth lens along the principal axis direction is designed to be D3 = 15mm. Through optical analysis software simulation, it is found that the maximum value of the wavefront image error of the collimated light beam emitted by the light source (780nm ~ 900nm) after passing through the first lens group and the second lens group is 0.2481λ, the minimum value is 0.24477λ, and the average error is 0.24595λ. At the same time, the maximum deviation of the wavefront parallelism of the collimated light beam emitted by the light source (780nm ~ 900nm) after passing through the first lens group and the second lens group is 24.144 microradians, the minimum is 23.361 microradians, and the average deviation is 23.775 microradians.

[0075] Through Figure 7 and Figure 8 By comparison, the imaging quality of the collimated beam deteriorates significantly, with the wave image deteriorating by four times and the parallelism deteriorating by five times.

[0076] The present disclosure also provides a detection device 70, comprising the above-mentioned optical component 10, a light source 12, an optical path system 13 and a sensor 14. The optical component 10 is located between the light source 12 and an object to be detected (e.g., a wafer), so that the light of the light source 12 generates a collimated light beam after passing through the optical component 10, and the collimated light beam generates a light signal to be detected (e.g., a reflected light signal, an interference light signal) after irradiating the object to be detected, and the light to be detected passes through the optical component 10 again, and is transmitted through the optical path system 13 and received by the sensor 14.

[0077] The optical component 10 is used to obtain collimated light and / or collect the optical signal to be detected. The light source can directly or indirectly irradiate the object to be detected to generate the optical signal to be detected. The optical path system 13 can be used to transmit the optical signal to be detected. The sensor can be used to receive the optical signal to be detected. In this way, the light source generates a collimated light beam after passing through the optical component, and the collimated light beam is irradiated onto the object to be detected to obtain the optical signal to be detected. After being collected by the optical component 10, the optical signal is transmitted to the sensor 14 through the optical path system 13.

[0078] For ease of understanding, the following Fig.12 The structure of the detection device 70 is briefly described by taking the detection of a wafer as an example, wherein the interference light is taken as an example of the light signal to be detected, and the principle of generating the interference light is obtained by the Sophie interferometer technique. It should be understood that the overall structure of the detection device should not be limited to the following description. For example, one or several elements introduced below can be omitted or replaced, and the layout relationship between them can be replaced.

[0079] The light source 12 obtains a collimated light beam after passing through the beam splitter assembly 77, the 1 / 4 wave plate assembly 76 and the optical assembly 10, and irradiates the wafer W and the standard mirror 74 to generate an interference light signal, which is collected by the optical assembly 10 and transmitted to the optical path system 13. Preferably, the distance between the wafer W and the second lens group (two lenses close to the wafer) in the optical assembly meets the following conditions: 15 to 50 mm. The interference light signal first passes through the aperture 78 in the optical path system 13, and then passes through the optical beam splitter assembly 750 to be divided into two channels for transmission in a certain proportion to perform detection of different performances or different sizes. Among them, the first channel A1 light beam can pass through the relay assembly 71 (used to transmit light signals to avoid large losses and changes during transmission), the beam scanning assembly 73 (for example, a movable scanning galvanometer, preferably, by moving two scanning galvanometers perpendicular to each other, scanning of different positions of the wafer W is achieved), the first imaging assembly 72 (used to achieve high-resolution detection of the wafer, for example, the light signal to be detected can be amplified) and the first sensor 14' after passing through the beam deflection assembly 750. The second channel A2 includes a second imaging component 81 (used to achieve lower resolution detection, for example, the magnification is lower than that of the first imaging component 72, so as to obtain full-aperture measurement of the wafer) and a second sensor 14. When the deflecting mirror assembly 750 is located at the fourth position B1, the light signal to be detected can be received by the first channel A1, and when the deflecting mirror assembly 750 is located at the second position B2, the interference light signal can be received by the second channel A2, and finally received by the sensor 14, for detection of the overall surface of the wafer or other performance parameters. Exemplarily, the deflecting mirror assembly 750 can also be a spectroscope or a spectroscopic prism, which splits light according to the energy ratio, which can be 50:50, 30:70, etc., so that the first channel and the second channel can work simultaneously, thereby obtaining different performance parameters (such as different resolutions) of the wafer at the same time. Among them, AA represents a cross-sectional view of the deflecting mirror assembly 750 in the direction perpendicular to the paper in the actual light path. Of course, the optical path system can also have only one detection channel, which is not specifically limited here.

[0080] It should be noted that the central air gap L between the first lens group and the second lens group along the principal axis direction meets 1299mm<L<1301mm, preferably, 1299.5mm≤L≤1300.5mm, for example, it can be 1299.5mm, 1300mm, 1300.5mm.

[0081] It should also be noted that due to different working wavelengths, the chromatic aberration can be eliminated by slightly adjusting the distance between the optical component and the light source. For example, the axial distance Ls between the first side 111 of the first lens 110 and the light source satisfies 363 mm < Ls < 365 mm. Preferably, Ls = 364 mm. If the light source band is extended to the visible light band of 480 nm to 650 nm, the axial distance Ls between the light source and the first side 111 needs to be increased by 0.27 mm to 9.6 mm. For example, when the light source is 480 nm, Ls needs to be increased by 9.6 mm. Exemplarily, when the light source is 650 nm, Ls needs to be increased by 0.27 mm.

[0082] It can be understood that in the present disclosure, azimuth descriptions such as "left" and "right" are relative rather than absolute. When the optical component provided in the present disclosure is placed in the posture and position shown in the drawings, these azimuth terms may be applicable.

[0083] It should be understood that although terms such as "first" or "second" may be used in the present disclosure to describe various elements (such as the first lens and the second lens), these elements are not defined by these terms, and these terms are only used to distinguish one element from another.

[0084] The basic principles of the present disclosure have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, advantages, effects, etc. mentioned in the present disclosure are only examples and not limitations, and it cannot be considered that these advantages, advantages, effects, etc. are essential for each embodiment of the present disclosure. In addition, the above-disclosed specific details are only for the purpose of illustration and easy understanding, rather than limitations, and the above details do not limit the present disclosure to necessarily adopt the above specific details to implement.

[0085] The above description has been given for purposes of illustration and description. In addition, this description is not intended to limit the embodiments of the present disclosure to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions, and sub-combinations thereof.

[0086] The components and devices involved in the present disclosure are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the drawings. As those skilled in the art will recognize, these components and devices can be connected, arranged, and configured in any manner.

[0087] The above is only the specific implementation manner of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present disclosure can easily think of changes or substitutions, which should be covered by the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. An optical component, characterized in that: include: The first lens group and the second lens group, The optical power of the first lens group is a negative value, The optical power of the second lens group is a positive value, in, The first lens group includes a first lens with a positive optical power, a second lens with a negative optical power, and a third lens with a positive optical power. There is a certain interval between the first lens, the second lens, and the third lens.

2. The optical assembly according to claim 1, wherein the first lens has a first side surface away from the second lens group and a second side surface close to the second lens group, and the curvature directions of the first side surface and the second side surface are both toward the second lens group, The second lens comprises a third side surface away from the second lens group and a fourth side surface close to the second lens group, and a curvature direction of the third side surface is opposite to a curvature direction of the fourth side surface. The third lens has a fifth side surface away from the second lens group and a sixth side surface close to the second lens group, the fifth side surface is a plane, and a curvature direction of the sixth side surface faces the second lens group.

3. The optical component according to claim 2, wherein the first side surface is a spherical surface with a curvature radius R 11 Comply with -1990mm<R 11 <-1970mm, the second side surface is a spherical surface with a curvature radius R 12 Comply with -211mm<R 12 <-201mm, the third side surface is a spherical surface with a curvature radius R 21 Comply with -247mm<R 21 <-237mm, the fourth side surface is a spherical surface with a curvature radius R 22 Comply with 693mm<R 22 <708mm, the sixth side surface is a spherical surface with a curvature radius R 32 Comply with -188mm<R 32 <-182mm. 4 . The optical assembly according to claim 1 , wherein the Abbe number of the first lens is greater than 60, the Abbe number of the second lens is greater than 20 and less than 50, and the Abbe number of the third lens is greater than 60.

5. The optical assembly according to claim 4, wherein the optical power of the first lens is satisfy: The focal length of the second lens satisfy: The focal length of the third lens satisfy:

6. The optical assembly according to claim 1, wherein the second lens group comprises a fourth lens and a fifth lens, the fourth lens has a seventh side surface facing the first lens group and an eighth side surface away from the first lens group, the seventh side surface is a plane, and a curvature direction of the eighth side surface is away from the first lens group. 7 . The optical component according to claim 6 , wherein a radius of curvature R1 of the eighth side surface satisfies −796 mm<R1<−782 mm.

8. The optical assembly according to claim 6, wherein the fifth lens has a ninth side surface away from the second lens group and a tenth side surface facing the second lens group, the ninth side surface is a plane, and a curvature direction of the tenth side surface is away from the second lens group. 9 . The optical component according to claim 8 , wherein a radius of curvature R2 of the tenth side surface satisfies 1790 mm<R2<1810 mm.

10. A detection device, characterized in that: include: The optical component, light source, optical path system and sensor according to any one of claims 1 to 9, In which, the optical component is located between the light source and the object to be detected, so that the light from the light source generates a collimated light beam after passing through the optical component, and the collimated light beam generates a light signal to be detected after irradiating the object to be detected. The light signal to be detected passes through the optical component again, is transmitted through the optical path system, and is received by the sensor.

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