Optical assembly and detection device

Abstract

An embodiment of the present disclosure provides an optical assembly and a detection device having the same, which comprises a first lens group and a second lens group arranged in sequence along a collimated light path direction, the first lens group has a negative optical power, and the second lens group has a positive optical power, the first lens group comprises 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, and there is a certain interval between the first lens, the second lens and the third lens. The collimated light path direction is a direction along which light propagates from a light source to an object to be detected, so as to realize collection of light rays with a large angle and facilitate correction of aberration, thus not only helping to solve the problem that the existing optical system is difficult to simultaneously realize collimated light beams, effective collection of light rays with a large angle and correction of chromatic aberration, but also helping to improve the compactness of the system and reduce the manufacturing cost.

Description

Technical Field

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

[0002] The field of wafer defect inspection (hereinafter referred to as wafer inspection) mainly covers three major categories of methods: appearance inspection, electron beam inspection, and optical inspection. Among them, optical inspection 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 inspection, and has become the focus of industry attention.

[0003] Wafer inspection, especially when using interferometers, requires not only illuminating the wafer surface with a highly parallel collimated beam, but also collecting the light rays to be tested to reflect the wafer's surface properties. Particularly important is the large angle of incidence of the collected light rays due to the wafer's warpage (hereinafter referred to as large-angle light collection). Collecting these large-angle rays is crucial for obtaining high-precision inspection results. Furthermore, the operating wavelength needs to cover the visible to infrared range to broaden the measurement range.

[0004] However, wavelengths in different bands will produce significant chromatic aberrations during transmission, which poses a challenge to detection accuracy. Existing optical path systems, while obtaining collimated beams, often struggle to effectively collect large-angle light and have certain shortcomings 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, which aims to solve the problem that existing optical path systems are unable to simultaneously achieve collimated beams, effectively collect large-angle light, and correct chromatic aberration.

[0006] On one hand, the optical assembly provided in this disclosure includes a first lens group and a second lens group arranged sequentially along the collimating optical path direction, wherein the optical power of the first lens group is... The negative value indicates the optical power of the second lens group. It is a positive value. + >0. The interval L between the first lens group and the second lens group satisfies: 0.3 / ≤L≤0.8 / 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, with a certain interval between the first lens, the second lens, and the third lens.

[0007] First, since the total optical power of the optical components is positive, and the second lens group bears a larger optical power, this means that the optical components can effectively change the propagation direction of light, which is beneficial for converging and correcting diverging light from the light source into a parallel beam. Second, 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, pushing the principal plane formed by the backward extension of the light to be detected outside the optical components (i.e., to the right of the second lens group), which helps to improve the compactness of the optical components structure. Third, the spacing L between the lens groups can be adjusted according to the system size requirements, improving the flexibility of the optical components. Finally, the first lens group forms a classic Cooke three-element lens with positive, negative, and positive optical powers respectively. This roughly symmetrical optical power combination design is not only simple in structure, but also helps to collect large-angle light, and produces small asymmetric aberrations (such as coma, astigmatism, chromatic aberration, etc.), resulting in good image quality.

[0008] On the other hand, this disclosure provides a detection device, which includes the aforementioned optical component, light source, optical path system, and sensor. The optical component is located between the light source and the object to be detected, such that the light from the light source, after passing through the optical component, generates a collimated beam. The collimated beam illuminates the object to be detected, generating a light signal to be detected. This light signal then passes through the optical component again, is transmitted through the optical path system, and is received by the sensor. Attached Figure Description

[0009] It should be understood that the following figures only illustrate certain embodiments of this disclosure and should not be construed as limiting the scope.

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

[0011] It should be understood that the accompanying drawings are only schematic, and the dimensions and scales of the elements in the drawings are not necessarily precise.

[0012] Figure 1 This is a schematic diagram of the structure of an optical component provided in an embodiment of the present disclosure.

[0013] Figure 2 for Figure 1 The optical path diagram in the middle serves as the collimation optical path.

[0014] Figure 3 for Figure 1 The optical path diagram in the middle serves as the light path for collecting light.

[0015] Figure 4 This is a schematic diagram of the structure of a first lens group provided in an embodiment of the present disclosure.

[0016] Figure 5 This is a schematic diagram of the structure of the second lens group provided in an embodiment of the present disclosure.

[0017] Figure 6 This is a schematic diagram of the structure of an optical component provided in an embodiment of the present disclosure.

[0018] Figure 7 According to Figure 6 Wavefront aberration map of the collimated beam obtained by the provided optical components.

[0019] Figure 8 According to Figure 6 Parallelism deviation diagram of the collimated beam obtained by the provided optical components.

[0020] Figure 9 The wavefront aberration diagram is shown for a collimated beam obtained using the optical components provided in Comparative Example 1.

[0021] Figure 10 This is a diagram showing the parallelism deviation of the collimated beam obtained using the optical components provided in Comparative Example 1.

[0022] Figure 11 The image shows the wavefront aberration of the collimated beam obtained using the optical components provided in Comparative Example 2.

[0023] Figure 12 This is a diagram showing the parallelism deviation of the collimated beam obtained using the optical components provided in Comparative Example 2.

[0024] Figure 13 According to Figure 6 A diffuse pattern of light collected by the provided optical components.

[0025] Figure 14 According to Figure 6 Wavefront error diagram of light collected by the provided optical components.

[0026] Figure 15 This is a schematic diagram of the structure of a detection device provided in an embodiment of the present disclosure. Detailed Implementation

[0027] Optical inspection first requires a collimated beam to illuminate the object under inspection (e.g., a wafer) to acquire the light to be inspected, such as reflected light, transmitted light, or interference light. For example, inspection using interference light can be achieved using a Fizeau-type or Thyman Green-type laser interferometer system. Secondly, it's necessary to collect as much of the light as possible for subsequent imaging or other processing. Especially for large-size, high-precision inspections (e.g., wafers), the warpage often results in a large angle of incidence for the light, and large-aperture objects introduce even greater aberrations. Common optical components, such as interferometric inspection optical components, are designed to achieve a collimated beam while collecting the light at an angle of only ±0.1°, which is very small. This helps avoid significant aberrations (e.g., paraxial aberration), chromatic aberration, or uneven intensity distribution during light propagation. If large-angle light (i.e., light with a large angle of incidence) needs to be collected, more optical elements are required to handle the various aberrations introduced by large-angle light (e.g., off-axis aberration, large aperture) to maintain image quality. Furthermore, most common optical components operate in the 633nm band. For large-sized objects, in order to increase the detection range, the operating wavelength needs to cover multiple wavelengths from visible light to infrared light. Multiple wavelengths will cause color difference during propagation, which will seriously affect the quality of the collected light.

[0028] In view of this, one embodiment of the present disclosure provides an optical component and a detection device having the same. Compared with traditional optical components, the optical component provided in this disclosure uses two lens groups, and the first lens group has a higher optical power... The negative value indicates the optical power of the second lens group. It is a positive value, and + The first lens group, with a power greater than 0, obtains a collimated beam. Furthermore, the second lens group provides a larger optical power, which is beneficial for improving the compactness of the optical component structure. The first lens group, along the collimating optical path direction, sequentially 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 to achieve the collection of large-angle light and facilitate the correction of aberrations. In this way, it not only helps to solve the problem that existing optical path systems cannot simultaneously achieve collimated beams, 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 component 10 provided in the embodiments of this disclosure will be illustrated below with reference to specific embodiments and accompanying drawings. It should be understood that there are various ways to implement this disclosure, and it should not be construed as being limited to the embodiments described herein. The embodiments described herein are only for a more thorough and clear understanding of this disclosure.

[0030] One embodiment of this disclosure provides an optical component 10. The optical component 10 can serve as a collimation component for providing a collimated beam (see reference). Figure 2 It can also be used as a light-collecting component (see reference). Figure 3 It is used to collect the light to be detected, and can also be used as a collimation and light collection component (see reference). Figure 6 To facilitate understanding, the overall structure of the optical component 10 will be illustrated below with an example.

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

[0032] The optical power of the first lens group Negative values ​​are primarily used to correct higher-order and off-axis aberrations of optical components (such as fifth-order and seventh-order aberrations and aberrations of large-angle off-axis rays), and the optical power of the second lens group. It is a positive value and is mainly used to correct primary aberrations and paraxial aberrations of optical components (such as third-order aberrations and aberrations of paraxial small-angle, large-aperture rays). + >0. 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 helps to reduce the tolerance requirements for optical processing and assembly.

[0033] Since the total optical power of the optical components is positive, and the second lens group bears a larger optical power, this means that the optical components can quickly change the propagation direction of light, which is beneficial for focusing and correcting the light from the light source into a parallel 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 principal plane formed by the backward extension of the light to be detected is pushed outside the optical components (away from the direction of the light source, i.e., to the right of the second lens group), which helps to improve the compactness of the optical component structure.

[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: 0.3 / ≤L≤0.8 / If the interval L between the first lens group 100 and the second lens group 200 is less than 0.3 / As the size of the optical components increases, if the interval L between the first lens group 100 and the second lens group 200 is greater than 0.8 / Although the size of the optical components is reduced, aberration correction is difficult to completely eliminate, resulting in a significant deterioration in image quality. For example, the spacing L can be 0.4 / 0.5 / 0.6 / 0.7 / 0.8 / There are no specific limitations here; the spacing can be selected based on the actual needs of the optical components. In this way, the distance L between lens groups can be adjusted according to the system size requirements, improving the flexibility of the optical components.

[0035] It is worth noting that the optical power of the first lens group... Optical power of the second lens group The absolute value is not specifically limited. To obtain high-quality image quality, preferably, 15 < <19. If the ratio of optical power is greater than 19, it is difficult to completely eliminate off-axis aberrations, on-axis aberrations, and aberrations caused by large apertures caused by large-angle light, resulting in a significant deterioration in image quality. If the ratio of optical power is less than 15, the tolerance performance of the optical components deteriorates significantly, and the processing and assembly of the optical components of the first lens group become significantly more difficult. For example, It can be 16, 16.5, 17, 17.5, or 18; no specific limit is specified here.

[0036] Combination Figure 1 and Figure 3 The first lens group 100 includes, in sequence along the collimating optical path, optical power... The first lens 110 is positive, and its optical power is... The second lens 120 and optical power are negative values. The third lens 130 is positive. Figure 3Optical component 10 serves as a light-collecting component, used to collect light, such as light to be detected, and to obtain characteristic parameters of the light, such as morphology, thickness, and warpage. The light to be detected, located to the right of the second lens group 200, passes through the second lens group 200 and the first lens group 100, forming a more convergent beam that is received by subsequent systems, such as an optical path system or a detection system. Therefore, the direction of light propagation in the light-collecting optical path 10b is opposite to the direction of light propagation in the collimating optical path 10a, to achieve optical path multiplexing. Of course, it can also be used independently as a light-collecting optical path or a collimating optical path. Furthermore, the first and third lenses, with positive optical power, primarily provide correction for negative higher-order aberrations, while the second lens, with negative optical power, primarily provides correction for positive higher-order aberrations.

[0037] It is worth noting that the first lens group forms a classic Cooke three-element lens with positive, negative, and positive optical powers respectively. This roughly symmetrical optical power design not only simplifies the structure but also helps collect large-angle light and minimizes asymmetric aberrations (such as coma, astigmatism, and chromatic aberration), resulting in good image quality. Furthermore, this structure has a numerical aperture of 0.2 to 0.25, compared to the 0.1 numerical aperture of traditional optical components, further enhancing light collection capabilities. In addition, this structure is the simplest lens combination capable of correcting all aberrations. By designing the radii of the six spherical surfaces of the three lenses and two air gaps, all aberrations are corrected, resulting in high-precision light, which facilitates subsequent imaging or detection.

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

[0039] This curved design helps to cancel out the aberration values ​​of the various optical surfaces, thereby reducing higher-order aberrations. For example, the first and third lenses primarily contribute negative third-order coma and third-order spherical aberration, while the second lens primarily contributes positive third- and fifth-order coma and third- and fifth-order spherical aberration. Furthermore, this combination can reduce off-axis aberrations by changing the direction of the incident light. For instance, the light ray being detected passes through the third, second, and first lenses sequentially, being converged, diverged, and then converged again, thus changing the angle of incidence and reducing off-axis aberrations.

[0040] Furthermore, since the bending directions of the first and third lenses are roughly the same, the first lens group forms a roughly symmetrical structure. At the same time, the third lens helps to share the radius of curvature with the first lens, thereby reducing the difficulty of optical element manufacturing process, reducing the difficulty of assembly and adjustment, assisting in the correction of primary spherical aberration and chromatic aberration, and avoiding the problem of insufficient aberration correction caused by having only one positive and one negative lens, thus helping to further improve the ability to correct distortion and field curvature.

[0041] As a concrete example, combined with Figure 2 and Figure 4 The first side surface 111 can be a sphere with a radius of curvature. Compliant with -1990mm < <-1970mm, used to receive light from the light source. Preferably, -1985mm ≤ ≤-1975mm. For example, The values ​​are -1985mm, -1982mm, -1980mm, -1978mm, and -1975mm, without specific limitations. The second side surface 113 can be a sphere with a radius of curvature of... Compliant with -211mm < <-201mm, preferably -209mm≤ ≤-203mm. For example, The values ​​are -203mm, -205mm, -206mm, -207mm, and -209mm, without specific limitations. The third side surface 121 can be a sphere with a radius of curvature of... Compliant with -247mm < <-237mm, preferably -244mm≤ ≤-240mm. For example, The dimensions can be -244mm, -242mm, or -240mm; no specific limitation is made here. The fourth side surface 123 can be a sphere with a radius of curvature... Meets 693mm < <708mm, preferably, 688mm≤ ≤703mm, for example, The dimensions can be 688mm, 701mm, or 703mm; no specific limitation is made here. The sixth side surface 133 can be a sphere with a radius of curvature. Compliant with -188mm < <-182mm, preferably -186≤ ≤-184mm. For example, It can be -186mm, -185mm, or -184mm; no specific limit is specified here.

[0042] By combining the bending direction and radius of curvature of the three lenses, it is helpful to further correct most of the aberrations and chromatic aberrations of the Seid image caused by the large-angle off-axis beam collection, as well as the small portion of paraxial Seid aberrations (mainly including spherical aberration, coma, astigmatism, and distortion). This helps to ensure that the imaging quality is close to the diffraction limit, providing a prerequisite for subsequent high-quality imaging and accurate detection.

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

[0044] It should be noted that the thickness of the central material between the first side surface 111 and the second side surface 113 of the first lens 110 along the principal axis is [missing information]. Meets the requirement of 19.8mm < <20.2mm, preferably, 19.9mm≤ ≤20.1mm, for example, The thickness can be 19.9mm, 20mm, or 20.1mm; no specific limitation is made here. The thickness of the material at the center along the principal axis between the third side surface 121 and the fourth side surface 123 of the second lens 120 is... Satisfies 12.1mm < <12.3mm, preferably, 12.15mm≤ ≤12.25mm, for example, The thickness can be 12.15mm, 12.2mm, or 12.25mm; no specific limitation is made here. The center material thickness along the principal axis between the fifth side surface 131 and the sixth side surface 133 of the third lens 130 is... Meets the requirement of 21.8mm < <22.2mm, preferably, 21.9mm≤ ≤22.1mm, for example, The thickness can be 21.9mm, 22mm, or 22.1mm; no specific limit is specified here.

[0045] Precise control of the thickness of each lens in the first lens group facilitates accurate control of the propagation state of the aligned or collected light beam, and is beneficial for correcting spherical aberration and other aberrations. Furthermore, by coordinating the thickness with the bending direction and radius of curvature, the accurate parameters of each lens can be obtained more precisely, thereby simulating the image quality after passing through the first lens group. This ensures that the imaging quality of the entire optical assembly can approach the diffraction limit, thus providing a prerequisite for subsequent imaging and accurate detection.

[0046] It is worth noting that the central air gap between the second side 113 and the third side 121 along the main axis is... Satisfying 0.9mm < <1.1mm, preferably, 0.95mm≤ ≤1.05mm, for example, The thickness can be 0.95mm, 1mm, or 1.05mm; no specific limitation is made here. The central air gap along the main axis between the fourth side 123 and the fifth side 131 is... And 7.8mm < <8.2mm, preferably, 7.9mm≤ ≤8.1mm, for example The thickness can be 7.9mm, 8mm, or 8.1mm; no specific limit is specified here.

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

[0048] To correct 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 crescent 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 biconcave heavy flint material. The Abbe number of the third lens 130 is greater than 60, and preferably, it can be made of plano-convex crown material.

[0049] Because a higher Abbe number results in a smaller difference in refractive index for different wavelengths, the first and third lenses are more effective at compensating for dispersion, while the second lens is less effective. Therefore, depending on the operating wavelength (visible light, e.g., 633 nm; near-infrared, e.g., 808 nm, 852 nm, 880 nm), lenses with different Abbe numbers are used to compensate for and coordinate with each other to reduce the difference in refractive index for different wavelengths, thereby eliminating chromatic aberration caused by different wavelengths.

[0050] To further correct the color difference caused by multiple wavelengths, continue to refer to Figure 3 and Figure 4 The optical power of the first lens 110 Satisfies: 0.00244 mm -1 < <0.00256 mm -1 Preferably, 0.00246 mm -1 ≤ ≤0.00254 mm -1 ,For example It can be 0.00246 mm. -1 0.00248 mm -1 0.00250 mm -1 0.00252 mm -1 and 0.00254 mm -1 No specific limitations are made here. The second lens has an optical power of 120. Satisfies: -0.00562 mm -1 < <-0.00543 mm -1 Preferably, -0.00558 mm -1 ≤ ≤-0.00547 mm -1 ,For example It can be -0.00557 mm. -1 -0.00554 mm -1 -0.00551 mm -1 and -0.00547 mm -1 No specific limitations are made here. The third lens has an optical power of 130. Satisfies: 0.00272mm -1 < <0.00278 mm -1 Preferably, 0.00273 mm -1 ≤ ≤0.00277 mm -1 ,For example It can be 0.00273 mm. -1 0.00274 mm -1 0.00275 mm -1 0.00276 mm -1 and 0.00277 mm -1 No specific limitations are made here.

[0051] Since the optical power can be adjusted to change the focusing position of different wavelengths of light, adjusting the optical power according to the wavelength of light used (from visible to near-infrared) helps to focus different wavelengths at the same position.

[0052] By combining the materials of the first lens group with the optical power, it is beneficial to further correct chromatic aberration. This ensures that the quality of light collection at multiple working wavelengths is not affected, thereby helping to ensure imaging quality and providing possibilities for subsequent imaging and accuracy measurement.

[0053] It should be noted that if the light source is a point source, for the collimating optical path 10a, the collimated light source usually needs to be filtered before being collimated again. This results in a larger nonlinear error and a lower signal-to-noise ratio in the obtained parallel light rays. This significantly reduces the accuracy and precision of the light rays obtained after illuminating the object under test, which is detrimental to high-precision imaging and detection. Therefore, the light source disclosed in this invention uses an extended light source with a size greater than 10 mm. This helps improve the detection capability and signal-to-noise ratio of the collimated beam, thereby improving the accuracy and precision of the detection.

[0054] To further improve the parallelism of the collimated beam and reduce the aberrations of paraxial rays caused by the extended light source, the reference... 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 flat, and the curvature of the eighth side surface 213 is towards the object to be detected 300. This design is advantageous for 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 diameter of the wafer. This is beneficial for covering the wafer surface with a large-aperture collimated beam and collecting the light to be detected reflected from the wafer surface or from the lens. Preferably, the diameter of the second lens group is greater than or equal to 1.05 times and less than or equal to 1.1 times the wafer size. In this way, the second lens group is not too large, which helps to reduce costs and also helps to collect the light to be detected, improving the collection effect.

[0057] It is worth noting that the radius of curvature of the eighth side 213 It can meet -796mm < <-782mm. Preferably, -792mm ≤ ≤-786mm, for example The thickness can be -792mm, -790mm, -789mm, or -786mm; no specific limit is specified here. Meanwhile, the center material thickness along the principal axis between the seventh side surface 211 and the eighth side surface 213... Meets 37.8mm < <38.2mm, preferably 37.9mm≤ ≤38.1mm, for example The thickness can be 37.9mm, 38mm, or 38.1mm; no specific limitation is made here. This facilitates the correction of third-order coma and third-order spherical aberration.

[0058] Continue to refer to 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 221 is a plane, and the curvature of the tenth side surface 223 faces the first lens group. A fifth lens with a negative optical power helps to provide positive coma and spherical aberration.

[0059] It is worth noting that the radius of curvature of the tenth side 223 Meets 1790mm < <1810mm, preferably, 1795mm≤ ≤1805mm, for example The thickness can be 1795mm, 1800mm, or 1805mm. Simultaneously, the center material thickness along the main axis between the ninth side surface 221 and the tenth side surface 223... Meets 21.8mm < <22.2mm, preferably 21.9mm≤ ≤22.1mm, for example The thickness can be 21.9mm, 22mm, or 22.1mm; no specific limit is specified here.

[0060] For large-aperture objects, numerous aberrations and spherical aberrations are introduced (the larger the aperture, the greater the square and cubic aberrations). By coordinating the bending direction and radius of curvature of the fourth and fifth lenses, it is beneficial to correct most of the Seid aberrations of large-aperture paraxial beams. Moreover, compared to existing methods using expensive aspherical lenses, this combination not only provides better overall correction, especially for off-axis rays, but also helps to further reduce costs.

[0061] It should be noted that the optical power of the fourth lens 210... It can meet the requirement of: 0.000816 mm -1 < <0.000844 mm-1 The fifth lens has an optical power of 220. It can meet -0.000289 mm -1 < <-0.000281 mm -1 Preferably, -0.000287 mm -1 ≤ ≤-0.000283 mm -1 ,For example It can be -0.000283 mm. -1 -0.000285mm -1 and -0.000287 mm -1 No specific limitations are made here.

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

[0063] For example, the central air gap between the seventh side 211 and the tenth side 223 along the main axis 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 and fifth lenses facilitates the correction of most aberrations caused by large-aperture paraxial beams, and significantly reduces manufacturing costs.

[0065] Based on the above two sets of five-piece optical path designs and material combinations, the wavefront error of the collimated beam emitted after the light source passes through the optical components is analyzed (refer to...). Figure 7 ) and parallelism (reference) Figure 8 ), and the diffusion pattern as a light-collecting component (see reference). Figure 13 ) and wavefront error diagram (reference) Figure 14 ).

[0066] 1. Reference Figure 7Calculations using optical analysis software show that the maximum wavefront error of the collimated beam emitted from the light source (780nm~900nm) after passing through the first and second lens groups is 0.0658λ, the minimum is 0.0653λ, and the average error is 0.0655λ. Wavefront distortion less than 0.07λ is considered ideal. Therefore, the aberrations generated by the optical components provided in this disclosure as a collimating optical path are almost negligible, enabling subsequent imaging and high-precision detection. The optical analysis software can be Zemax, CODE V, FRED, OptiFDTD, etc., and is not specifically limited here.

[0067] 2. Reference Figure 8 Calculations using optical analysis software showed that the maximum deviation of the wavefront parallelism of the collimated beam emitted from the light source (780nm~900nm) after passing through the first and second lens groups was 4.9501 microradians, the minimum was 4.8787 microradians, and the average deviation was 4.8973 microradians, all better than 5 microradians. This demonstrates that the collimated beam exhibits excellent collimation characteristics.

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

[0069] 4. Reference Figure 14 According to calculations using optical analysis software, after the collimated beam emitted from the light source (780nm~900nm) passes through the first and second lens groups and illuminates the surface of the object to be tested (wafer), the angle of the collected light beam is ±1.5° (compared to ±0.1° of the angle of the traditional incident light). Moreover, 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 Figure 9 and Figure 10 The radius of curvature of the second side surface 113 in the first lens 110 is designed as follows: Simulations using optical analysis software revealed that the maximum wavefront error of the collimated beam emitted from the light source (780nm~900nm) after passing through the first and second lens groups was 0.19685λ, the minimum was 0.18551λ, and the average error was 0.19038λ. Simultaneously, the maximum deviation in wavefront parallelism of the collimated beam emitted from the light source (780nm~900nm) after passing through the first and second lens groups was 19.677 microradians, the minimum was 15.933 microradians, and the average deviation was 18.024 microradians.

[0072] Through with Figure 7 and Figure 8 The comparison shows that the imaging quality of the collimated beam is significantly worse, with the wave image deteriorating by three times and the parallelism deteriorating by four times.

[0073] Comparative Example 2

[0074] refer to Figure 11 and Figure 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 is designed as follows: =15mm. Simulation using optical analysis software revealed that the maximum wavefront image error of the collimated beam emitted from the light source (780nm~900nm) after passing through the first and second lens groups was 0.2481λ, the minimum was 0.24477λ, and the average error was 0.24595λ. Simultaneously, the maximum deviation of the wavefront parallelism of the collimated beam emitted from the light source (780nm~900nm) after passing through the first and second lens groups was 24.144 microradians, the minimum was 23.361 microradians, and the average deviation was 23.775 microradians.

[0075] Through with Figure 7 and Figure 8 The comparison shows that the imaging quality of the collimated beam is significantly worse, with the wave image deteriorating by a factor of four and the parallelism deteriorating by a factor of five.

[0076] This disclosure also provides a detection device 70, including the aforementioned optical component 10, light source 12, optical path system 13, and sensor 14. The optical component 10 is located between the light source 12 and the object to be detected (e.g., a wafer), so that the light from the light source 12 is collimated after passing through the optical component 10. The collimated light then illuminates the object to be detected, generating a light signal to be detected (e.g., reflected light signal, interference light signal). The light to be detected passes through the optical component 10 again, is transmitted through the optical path system 13, and is received by the sensor 14.

[0077] Optical component 10 is used to obtain collimated light beams and / or collect the light signal to be detected. The light source can directly or indirectly illuminate the object to be detected to generate the light signal. Optical path system 13 can be used to transmit the light signal to be detected. Sensor can be used to receive the light signal to be detected. Thus, the light source generates a collimated beam after passing through the optical component; the collimated beam illuminates the object to be detected, obtaining the light signal to be detected. After being collected by optical component 10, the signal is transmitted to sensor 14 via optical path system 13.

[0078] To make it easier to understand, the following will be combined with Figure 12 The structure of the inspection device 70 is briefly described using wafer inspection as an example. The interference ray is generated using the optical signal to be inspected as an example, and the principle of interference ray generation is achieved through Sophie interferometry. It should be understood that the overall structure of the inspection device is not limited to the description below. For example, one or more elements mentioned below may be omitted or replaced, and their layout relationships may be altered.

[0079] The light source 12, after passing through the beam splitter assembly 77, the quarter-wave plate assembly 76, and the optical assembly 10, obtains a collimated beam, which illuminates the wafer W and the standard mirror 74 to generate an interference light signal. The interference light signal 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 is 15~50mm. The interference light signal first passes through the aperture 78 in the optical path system 13, and then is split into two channels by the optical beam splitter assembly 750 at a certain ratio for transmission, so as to perform detection of different performance or different sizes. The first channel A1 beam, after passing through the beam deflection assembly 750, can pass through the relay assembly 71 (used to transmit the light signal and avoid large losses and changes during transmission), the beam scanning assembly 73 (e.g., a movable scanning galvanometer, preferably, scanning of different positions of the wafer W is achieved by the movement of two mutually perpendicular scanning galvanometers), the first imaging assembly 72 (used to achieve high-resolution detection of the wafer, for example, it can amplify the light signal to be detected), and the first sensor 14'. The second channel A2 includes a second imaging component 81 (used to achieve lower resolution detection, such as a magnification lower than that of the first imaging component 72, to obtain full-aperture wafer measurement) and a second sensor 14. When the deflector component 750 is in the fourth position B1, the light signal to be detected can be received by the first channel A1. When the deflector component 750 is in 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 wafer surface or other performance parameters. Exemplarily, the deflector component 750 can also be a beam splitter or beam splitting prism, splitting the light according to an energy ratio, such as 50:50, 30:70, etc., so that the first and second channels can work simultaneously, thereby simultaneously obtaining different performance parameters of the wafer (e.g., different resolutions). Here, AA represents a cross-sectional view of the deflector component 750 along the direction perpendicular to the plane of the paper in the actual optical path. Of course, the optical path system can also have only one detection channel; no specific limitation is made here.

[0080] It should be noted that the central air gap between the first lens group and the second lens group along the principal axis is... It conforms to 1299mm < L < 1301mm, preferably 1299.5mm ≤ ≤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 finely 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, benefits, effects, etc. mentioned in the present disclosure are only examples and not limitations. It cannot be considered that these advantages, benefits, effects, etc. are essential for each embodiment of the present disclosure. Additionally, the above-disclosed specific details are only for illustrative and facilitating understanding purposes and are not limitations. The above details do not limit the present disclosure to necessarily adopt the above specific details for implementation.

[0085] The above description has been given for purposes of illustration and description. In addition, this description does not intend 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 do not intend 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 can easily think of changes or substitutions within the technical scope disclosed by the present disclosure, and all of them should be covered within 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, It consists of a first lens group and a second lens group arranged sequentially along the collimating optical path. Optical power of the first lens group It is a negative value. Optical power of the second lens group It is a positive value. + >0, where, Along the collimated optical path, the first lens group consists of a first lens with positive optical power, a second lens with negative optical power, and a third lens with positive optical power, with a certain interval between the first lens, the second lens, and the third lens; Along the collimating optical path, the second lens group consists of a fifth lens with negative optical power and a fourth lens with positive optical power. The first lens has a first side away from the second lens group and a second side close to the second lens group, and the curvature directions of the first side and the second side are both towards the second lens group. The second lens includes a third side surface away from the second lens group and a fourth side surface near the second lens group, wherein the curvature direction of the third side surface is opposite to that of the fourth side surface. The third lens has a fifth side surface away from the second lens group and a sixth side surface near the second lens group. The fifth side surface is flat, and the curvature of the sixth side surface faces the second lens group. The fourth lens has a seventh side facing the first lens group and an eighth side away from the first lens group. The seventh side is flat, and the curvature of the eighth side is away from the first lens group. The fifth lens has a ninth side facing the first lens group and a tenth side away from the first lens group. The ninth side is a plane, and the curvature of the tenth side faces the first lens group.

2. The optical component according to claim 1, wherein the first side surface is a sphere with a radius of curvature of... Compliant with -1990mm < <-1970mm, the second side surface is spherical, radius of curvature Compliant with -211mm < <-201mm, the third side surface is a sphere with a radius of curvature of Compliant with -247mm < <-237mm, the fourth side surface is a sphere with a radius of curvature of Meets 693mm < <708mm, the sixth side surface is a sphere with a radius of curvature of Compliant with -188mm < <-182mm.

3. The optical component 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.

4. The optical component according to claim 3, wherein the optical power of the first lens is... Satisfies: 0.00244 mm -1 < <0.00256 mm -1 The optical power of the second lens Satisfies: -0.00562 mm -1 < <-0.00543 mm -1 The optical power of the third lens Satisfies: 0.00272 mm -1 < <0.00278 mm -1 .

5. The optical component according to claim 1, wherein the radius of curvature of the eighth side surface... Meets -796mm < <-782mm.

6. The optical component according to claim 1, wherein the radius of curvature of the tenth side surface... Meets 1790mm < <1810mm.

7. A detection device, characterized in that, include: The optical components, light source, optical path system, and sensor as described in any one of claims 1-6 The optical component is located between the light source and the object to be detected, so that the light from the light source is collimated after passing through the optical component. The collimated beam illuminates the object to be detected and generates a light signal 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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