CN115931903B - Edge detection lens and system - Google Patents

Abstract

The present disclosure discloses an edge detection lens and system. The edge detection lens includes: a compound lens, an imaging lens group and a reflecting mirror; the compound lens includes: an edge detection lens in a first aperture range and a surface detection lens in a second aperture range; wherein the upper limit value of the first aperture range is smaller than or equal to the lower limit value of the second aperture range, and the curvature radius of the edge detection lens is different from that of the surface detection lens; the reflector is arranged above the upper surface of the wafer to be detected and/or below the lower surface of the wafer to be detected, and is used for reflecting detection light rays on the surface of the wafer to be detected to the surface detection lens and transmitting the detection light rays to the imaging lens group through the surface detection lens; the detection light of the edge surface of the wafer to be detected is transmitted to the imaging lens group through the edge detection lens. The edge detection lens can realize simultaneous detection of three directions of the edge of the wafer by using only one lens, and the equipment cost and the occupied space of the detection system are saved.

Description

Edge detection lens and system

Technical Field

The present disclosure relates generally to the field of optical detection technology. More particularly, the present disclosure relates to an edge detection lens and system.

Background

The wafer is a basic element for semiconductor production and manufacture, the quality of the wafer is critical for the subsequent semiconductor process, and the edge portion of the wafer needs to be inspected to ensure the overall quality of the product, wherein the edge portion of the wafer includes an edge surface (also can be regarded as a side surface of the wafer) and an upper surface and a lower surface connected with the edge surface. The three surfaces are usually required to be detected simultaneously, and because the three surfaces are oriented differently, it is difficult to simultaneously image the three parts using the same imaging system.

In the prior art, three imaging systems are typically used to image three portions separately, but this results in the whole detection system becoming very complex and requiring a large space, and at the same time, each detection direction requires a processor configured for processing the image, resulting in a significant increase in the cost of the detection system. The existing detection technology is an EdgeScan detection system scheme provided by ISRA, and the simultaneous detection of the three directions of the wafer edge is realized through the prism combination, but the scheme needs relatively complex light path combination and a large depth of field lens, so that the whole system is complex to install and adjust and has large volume.

In view of the foregoing, it is desirable to provide an edge inspection lens solution that can realize simultaneous inspection of three directions of the wafer edge using only one lens, thereby saving the equipment cost and the occupied space of the inspection system.

Disclosure of Invention

To address at least one or more of the technical problems mentioned above, the present disclosure proposes an edge detection lens solution in various aspects.

In a first aspect, the present disclosure provides an edge detection lens comprising: a compound lens 3 comprising: an edge detection lens 31 in a first aperture range and a surface detection lens 32 in a second aperture range; wherein an upper limit value of the first aperture range is less than or equal to a lower limit value of the second aperture range, and a radius of curvature of the edge detection lens 31 is different from a radius of curvature of the surface detection lens 32; an imaging lens group 4; the reflecting mirror 2 is arranged above the upper surface of the wafer 1 to be tested and/or below the lower surface of the wafer 1 to be tested, and is used for reflecting detection light rays on the surface of the wafer to be tested to the surface detection lens 32 and transmitting the detection light rays to the imaging lens group 4 through the surface detection lens 32; the detection light of the edge surface of the wafer to be detected is transmitted to the imaging lens group 4 through the edge detection lens 31.

In some embodiments, the edge detection lens 31 is a meniscus negative lens, the first surface of which faces the wafer 1 to be measured, and the absolute value of the radius of curvature of the first surface of the edge detection lens 31 is smaller than the absolute value of the radius of curvature of the second surface; the surface detection lens 32 is a meniscus positive lens, a first surface of the surface detection lens 32 faces the wafer 1 to be detected, and an absolute value of a radius of curvature of the first surface is smaller than an absolute value of a radius of curvature of a second surface.

In some embodiments, the first range of orifice has a lower limit of 0mm and an upper limit of between 10mm and 15 mm; the lower limit value of the second caliber range is equal to the upper limit value of the first caliber range, and the upper limit value is greater than or equal to 50mm.

In some embodiments, the radius of curvature of the first face of the edge detection lens 31 is between-44 mm and-36 mm; the radius of curvature of the second face of the edge detection lens 31 is between-66 mm and-54 mm; the radius of curvature of the first face of the surface detection lens 32 is between 50.4mm and 61.6 mm; the radius of curvature of the second face of the surface detection lens 32 is between 50.4mm and 61.6 mm.

In some embodiments, the edge detection lens 31 has a thickness between 35.34mm and 43.20 mm; the thickness of the surface detection lens 32 is between 36mm and 44 mm.

In some embodiments, the refractive index of the edge detection lens 31 is between 1.692 and 2.068, and the abbe number is between 37 and 45; the refractive index of the surface detection lens 32 is between 1.692 and 2.068, and the Abbe number is between 37 and 45.

In some embodiments, the distance between the compound lens 3 and the wafer 1 to be tested is between 36mm and 44 mm.

In some embodiments, the imaging lens group 4 includes: the first lens 41 is a meniscus negative lens; the first surface of the first lens faces the second surface of the edge detection lens, and the absolute value of the curvature radius of the first surface of the first lens is smaller than that of the second surface; the second lens 42 is a biconcave lens; the third lens 43 is a biconvex lens; the third lens is glued with the second lens; the fourth lens 44 is a biconvex lens; the fifth lens 45 is a biconcave lens; the fifth lens is glued with the fourth lens; the sixth lens 46 is a meniscus positive lens; the first surface of the sixth lens faces the fifth lens, and the absolute value of the curvature radius of the first surface of the sixth lens is smaller than that of the second surface; the seventh lens 47 is a biconcave lens; the eighth lens 48 is a biconvex lens; the eighth lens is glued with the seventh lens; the ninth lens 49 is a biconvex lens.

In some embodiments, the radius of curvature of the first face of the first lens 41 is between-37.07 mm and-30.33 mm; the radius of curvature of the second face of the first lens 41 is between-50.42 mm and-41.25 mm; the radius of curvature of the first face of the second lens 42 is between-415.71 mm and-340.13 mm; the second face of the second lens 42 has a radius of curvature of between 53.89mm and 65.87 mm; the radius of curvature of the first face of the third lens 43 is between 53.89mm and 65.87 mm; the radius of curvature of the second face of the third lens 43 is between-86.33 mm and-70.63 mm; the radius of curvature of the first face of the fourth lens 44 is between 120.46mm and 147.23 mm; the radius of curvature of the second face of the fourth lens 44 is between-62.4 mm and-51.1 mm; the radius of curvature of the first face of the fifth lens 45 is between-62.40 mm and-51.05 mm; the radius of curvature of the second face of the fifth lens 45 is between 367.8mm and 449.5 mm; the radius of curvature of the first face of the sixth lens 46 is between 78.17mm and 95.55 mm; the radius of curvature of the second face of the sixth lens 46 is between 458.8mm and 560.8 mm; the radius of curvature of the first face of the seventh lens 47 is between-38.92 mm and-31.84 mm; the radius of curvature of the second face of the seventh lens 47 is between 141.5mm and 172.9 mm; the radius of curvature of the first face of the eighth lens 48 is between 141.5mm and 172.9 mm; the radius of curvature of the second face of the eighth lens 48 is between-77.34 mm and-63.27 mm; the radius of curvature of the first face of the ninth lens 49 is between 1120mm and 1369 mm; the radius of curvature of the second face of the ninth lens 49 is between-257 mm and-210 mm.

In a second aspect, the present disclosure provides an edge detection system comprising: an image detection apparatus, an imaging apparatus, and an edge detection lens as described in any one of the first aspects; the imaging device is configured to: forming a wafer surface image and a wafer edge image according to the detection light rays in the edge detection lens, and sending the wafer surface image and the wafer edge image to the image detection equipment; wherein, the detecting light includes: detecting light rays of the surface of the wafer to be detected and detecting light rays of the edge surface of the wafer to be detected; the image detection device is configured to: and performing defect detection according to the wafer surface image and the wafer edge image sent by the imaging equipment, and outputting an edge detection result of the wafer to be detected.

With the edge detection lens provided as above, the embodiments of the present disclosure pass through a compound lens including an edge detection lens in a first aperture range and a surface detection lens in a second aperture range, wherein a radius of curvature of the edge detection lens is different from a radius of curvature of the surface detection lens, so that the edge detection lens and the imaging lens group constitute a detection lens of a wafer edge face. The reflector arranged above the upper surface of the wafer to be detected and/or below the lower surface of the wafer to be detected can reflect detection light rays on the surface of the wafer to the surface detection lens, so that the reflector, the surface detection lens and the imaging lens group form a detection lens on the surface of the wafer. That is, the edge detection lens provided by the present disclosure, the parts of different aperture ranges of the compound lens can respectively form two groups of detection lenses of different orientation parts of the wafer with the multiplexed imaging lens groups, so that the edge detection lens has different object space working distances at different apertures, and further, the edge detection lens can simultaneously realize clear imaging of three directions of the edge of the wafer, and can simultaneously detect the three directions of the edge of the wafer, and compared with the detection system in the prior art, the edge detection lens saves a large number of optical path prisms and image processing devices, and further reduces the volume and cost of the detection system.

Drawings

The above, as well as additional purposes, features, and advantages of exemplary embodiments of the present disclosure will become readily apparent from the following detailed description when read in conjunction with the accompanying drawings. Several embodiments of the present disclosure are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar or corresponding parts and in which:

FIG. 1 is a schematic diagram of a prior art wafer edge inspection scheme;

FIG. 2 is a schematic diagram of another wafer edge inspection scheme in the prior art;

FIG. 3 illustrates an exemplary block diagram of an edge detection lens of some embodiments of the present disclosure;

FIG. 4 illustrates an exemplary partial enlarged view of an edge detection lens of some embodiments of the present disclosure;

FIG. 5 illustrates an exemplary block diagram of a wafer edge facet inspection lens according to an embodiment of the present disclosure;

FIG. 6 illustrates a point-column diagram of a wafer edge surface inspection lens according to an embodiment of the present disclosure;

FIG. 7 illustrates an optical modulation function curve of a wafer edge facet inspection lens according to an embodiment of the present disclosure;

FIG. 8 illustrates an exemplary block diagram of a wafer surface inspection lens according to an embodiment of the present disclosure;

FIG. 9 illustrates a point-to-point diagram of a wafer surface inspection lens in accordance with an embodiment of the present disclosure;

fig. 10 shows an optical modulation function curve of a wafer surface inspection lens according to an embodiment of the present disclosure.

Description of the embodiments

The following description of the embodiments of the present disclosure will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the disclosure. Based on the embodiments in this disclosure, all other embodiments that may be made by those skilled in the art without the inventive effort are within the scope of the present disclosure.

It should be understood that the terms "comprises" and "comprising," when used in this specification and the claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the present disclosure is for the purpose of describing particular embodiments only, and is not intended to be limiting of the disclosure. As used in the specification and claims of this disclosure, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be further understood that the term "and/or" as used in the present disclosure and claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.

As used in this specification and the claims, the term "if" may be interpreted as "when..once" or "in response to a determination" or "in response to detection" depending on the context. Similarly, the phrase "if a determination" or "if a [ described condition or event ] is detected" may be interpreted in the context of meaning "upon determination" or "in response to determination" or "upon detection of a [ described condition or event ]" or "in response to detection of a [ described condition or event ]".

Specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

Wafer is a basic element for semiconductor production and manufacture, the quality of the wafer is critical for the subsequent semiconductor process, and wafer edge detection is also an important link affecting the quality of semiconductor products. The wafer edge can be divided into an edge surface and an upper surface and a lower surface, wherein the edge surface is a wafer side surface parallel to the thickness direction of the wafer, and the wafer upper surface and the wafer lower surface are connected with the edge surface.

Fig. 1 is a schematic diagram of a conventional wafer edge inspection scheme. Because the orientations of the wafer edge surface and the upper surface and the lower surface of the wafer edge surface are different, the existing wafer edge detection scheme is provided with a group of imaging systems respectively in three orientations, which results in complex equipment and large occupied space of the whole detection system.

Fig. 2 is a schematic diagram of another conventional wafer edge inspection scheme. The simultaneous detection of the three directions of the edge of the wafer is realized through the prism combination, but the scheme needs relatively complex light path combination and a large depth of field lens, so that the whole system is complex to install and adjust and has large volume.

In view of the foregoing, an embodiment of the disclosure provides an edge detection lens scheme for partitioning a detection light path by a compound lens with different radii of curvature at different apertures, wherein a surface detection lens portion of the compound lens, a mirror and an imaging lens group form a detection lens of a wafer surface, and an edge detection lens portion of the compound lens and the imaging lens group form a detection lens of an edge surface of the wafer. The design of the compound lens with different curvature radiuses at different calibers enables the edge detection lens to have different object space working distances at different calibers, so that the edge detection lens can clearly image three directions of the edge surface and the upper surface and the lower surface of the wafer at the same time, the three directions of the edge of the wafer can be detected at the same time, and a large amount of space and the use of optical elements are saved.

In view of the foregoing, an embodiment of the disclosure provides an edge detection lens scheme for partitioning a detection light path by a compound lens with different radii of curvature at different apertures, wherein a surface detection lens portion of the compound lens, a mirror and an imaging lens group form a detection lens of a wafer surface, and an edge detection lens portion of the compound lens and the imaging lens group form a detection lens of an edge surface of the wafer. The design of the compound lens with different curvature radiuses at different calibers enables the edge detection lens to have different object space working distances at different calibers, so that the edge detection lens can clearly image three directions of the edge surface and the upper surface and the lower surface of the wafer at the same time, the three directions of the edge of the wafer can be detected at the same time, and a large amount of space and the use of optical elements are saved.

Fig. 3 illustrates an exemplary block diagram of an edge detection lens of some embodiments of the present disclosure.

Fig. 4 illustrates an exemplary partial enlarged view of an edge detection lens of some embodiments of the present disclosure.

As shown in fig. 3, an edge detection lens provided in an embodiment of the present disclosure includes: a mirror 2, a compound lens 3 and an imaging lens group 4.

As shown in fig. 4, the compound lens 3 includes: an edge detection lens 31 in the first aperture range and a surface detection lens 32 in the second aperture range. The upper limit value of the first aperture range is less than or equal to the lower limit value of the second aperture range, and it is understood that the surface detection lens 32 is in a circular shape, and the edge detection lens 31 is a circular lens embedded in the circular inner diameter range.

As shown in fig. 4, the compound lens 3 includes: an edge detection lens 31 in the first aperture range and a surface detection lens 32 in the second aperture range. The upper limit value of the first aperture range is less than or equal to the lower limit value of the second aperture range, and it is understood that the surface detection lens 32 is in a circular shape, and the edge detection lens 31 is a circular lens embedded in the circular inner diameter range.

As shown in fig. 4, the compound lens 3 includes: an edge detection lens 31 in the first aperture range and a surface detection lens 32 in the second aperture range. The upper limit value of the first aperture range is less than or equal to the lower limit value of the second aperture range, and it is understood that the surface detection lens 32 is in a circular shape, and the edge detection lens 31 is a circular lens embedded in the circular inner diameter range.

The reflecting mirror 2 is arranged above the upper surface of the wafer to be tested and/or below the lower surface of the wafer to be tested, the detection light rays on the surface of the wafer to be tested are firstly projected to the reflecting mirror 2, the reflection mirror 2 reflects the detection light rays to the surface detection lens 32, and the detection light rays are transmitted to the imaging lens group 4 through the surface detection lens 32 and then enter the imaging device to form a wafer surface image.

It will be appreciated that the mirror 2, the surface inspection lens 32 and the imaging lens group 4 constitute an inspection lens for the surface of the wafer 1 to be inspected.

The detection light of the edge surface of the wafer 1 to be detected is directly projected to the edge detection lens 31, and is transmitted to the imaging lens group 4 through the edge detection lens 31. That is, the edge detection lens 31 and the imaging lens group 4 constitute a detection lens of the edge face of the wafer 1 to be measured.

In the edge detection lens provided in the embodiment of the disclosure, the compound lens has different radii of curvature in different aperture ranges, so as to form at least two lens partitions, and the two lens partitions multiplex a group of imaging lens groups to form two groups of detection lenses. The composite lens enables the edge detection lens to have different object space working distances at different caliber positions, and further detection light rays of the wafer surface and the wafer edge surface can be clearly imaged in the same imaging equipment.

In some embodiments, the edge detection lens 31 and the surface detection lens 32 may be made of the same material, for example: the optical glass with the model of H-ZLAF68C has the refractive index of between 1.692 and 2.068 and the Abbe number of between 37 and 45. Alternatively, the refractive index of the edge detection lens 31 may be 1.88, and the abbe number 40.9; the refractive index of the surface detection lens 32 may be 1.88 and the abbe number 40.9.

The optical parameters of the compound lens 3 are further described below.

In some embodiments, the edge detection lens 31 is a meniscus negative lens, with its first surface facing the wafer 1 to be measured, and its first surface having a smaller absolute value of curvature than the second surface. That is, the concave surface of the edge detection lens 31 faces the wafer 1 to be measured.

Illustratively, the radius of curvature of the first face of the edge detection lens 31 is between-44 mm and-36 mm; the radius of curvature of the second face of the edge detection lens 31 is between-66 mm and-54 mm. Optionally, the radius of curvature of the first face of the edge detection lens 31 is-40.043 mm and the radius of curvature of the second face is-60.250 mm.

In some embodiments, the edge detection lens 31 has a thickness between 35.34mm and 43.20 mm. Alternatively, the thickness of the edge detection lens 31 is 39.267mm.

In some embodiments, the surface inspection lens 32 is a meniscus lens with a first surface facing the wafer 1 to be inspected, and the absolute value of the radius of curvature of the first surface is smaller than that of the second surface. That is, the convex surface of the surface inspection lens faces the wafer 1 to be inspected.

Illustratively, the radius of curvature of the first face of the surface sensing lens 32 is between 50.4mm and 61.6 mm; the radius of curvature of the second face of the surface detection lens 32 is between 50.4mm and 61.6 mm. Alternatively, the radius of curvature of the first face of the surface detection lens 32 is 56.034mm and the radius of curvature of the second face is 56.106mm.

In some embodiments, the thickness of the surface sensing lens 32 is between 36mm and 44 mm. Alternatively, the thickness of the surface detection lens 32 is 39.997mm.

When edge detection of the wafer 1 to be detected is performed, the distance between the compound lens 3 and the wafer 1 to be detected can be set to be 40mm, the thickness of the wafer is set to be 1mm, the total view field of the object space of the lens is set to be 40mm, and the object distance corresponding to the surface of the wafer is 19.5mm more than that of the edge surface, so that the distance from the surface of the wafer to the surface detection lens is 59.5mm, wherein the distance from the surface of the wafer to the surface detection lens can be understood as the distance from the center of the reflecting mirror to the surface detection lens.

According to the edge detection lens provided by the embodiment, the parts of different aperture ranges of the compound lens can respectively form two groups of detection lenses of different orientation parts of a wafer with the multiplexed imaging lens groups, and the object distances from the upper surface and the lower surface of the edge of the wafer to the edge detection lens are adjusted through the compound lens, so that the edge detection lens can realize clear imaging of the edge of the wafer in three directions at the same time, and therefore, the simultaneous detection of the three directions is realized, and compared with a detection system in the prior art, the edge detection lens saves an optical path prism and image processing equipment, and further reduces the volume and cost of the detection system.

The imaging lens group 4 in the edge detection lens of the present disclosure is described in detail below.

In the present disclosure, the imaging lens group 4 is multiplexed in two groups of inspection lenses, i.e., the inspection lens on the wafer surface and the inspection lens on the wafer edge surface, so that the cost of multiple sets of optical lens groups used in the existing wafer edge inspection scheme is saved, and the volume of the whole inspection system is reduced.

In some embodiments, the imaging lens group 4 may include:

the first lens 41 is a meniscus negative lens. The first surface of the first lens 41 faces the second surface of the edge detection lens 31, and the absolute value of the radius of curvature of the first surface of the first lens 41 is smaller than that of the second surface.

The second lens 42 is a biconcave lens.

Further, the first surface of the second lens 42 faces the second surface of the first lens 41, and the absolute value of the radius of curvature of the first surface of the second lens 42 is larger than that of the second surface.

The third lens 43 is a biconvex lens. The first face of the third lens 43 is glued to the second face of the second lens 42.

Further, the absolute value of the radius of curvature of the first surface of the third lens 43 is smaller than the absolute value of the radius of curvature of the second surface.

The fourth lens 44 is a biconvex lens.

Further, the first surface of the fourth lens 44 faces the second surface of the third lens 43, and the absolute value of the radius of curvature of the first surface of the fourth lens 44 is larger than that of the second surface.

The fifth lens 45 is a biconcave lens. The first face of the fifth lens 45 is cemented with the second face of the fourth lens 44.

Further, the absolute value of the radius of curvature of the first surface of the fifth lens 45 is smaller than the absolute value of the radius of curvature of the second surface.

The sixth lens 46 is a meniscus positive lens. The first surface of the sixth lens 46 faces the second surface of the fifth lens 45, and the absolute value of the radius of curvature of the first surface of the sixth lens 46 is smaller than that of the second surface.

And a seventh lens 47, which is a biconcave lens.

Further, the first surface of the seventh lens 47 faces the second surface of the sixth lens 46, and the absolute value of the radius of curvature of the first surface of the seventh lens 47 is smaller than that of the second surface.

The eighth lens 48 is a biconvex lens. The first face of the eighth lens 48 is cemented with the second face of the seventh lens 47.

Further, the absolute value of the radius of curvature of the first surface of the eighth lens 48 is larger than the absolute value of the radius of curvature of the second surface.

The ninth lens 49 is a biconvex lens.

Further, the first face of the ninth lens 49 faces the second face of the eighth lens 48, and the absolute value of the radius of curvature of the first face of the ninth lens 49 is larger than that of the second face.

The optical parameters of each lens in the imaging lens group are further described below.

Illustratively, the first face of the first lens 41 has a radius of curvature of between-37.07 mm and-30.33 mm and the second face has a radius of curvature of between-50.42 mm and-41.25 mm. Alternatively, the radius of curvature of the first face of the first lens 41 is-33.700 mm and the radius of curvature of the second face is-45.836 mm.

The thickness of the first lens 41 is illustratively between 9mm and 11 mm. Optionally, the thickness of the first lens is 10mm.

For example, the first lens may be an optical glass of type H-LAK59A, with a refractive index between 1.521 and 1.859 and an abbe number between 49.41 and 60.39. Alternatively, the refractive index of the first lens is 1.69 and the abbe number is 54.9.

Illustratively, the radius of curvature of the first face of the second lens 42 is between-415.71 mm and-340.13 mm, and the radius of curvature of the second face is between 53.89mm and 65.87 mm. Optionally, the radius of curvature of the first face of the second lens 42 is-377.922 mm and the radius of curvature of the second face is 59.883mm.

The thickness of the second lens 42 is between 18mm and 22mm, for example. Alternatively, the thickness of the second lens 42 is 20mm.

Illustratively, the distance between the second lens 42 and the first lens 41 is between 9mm and 11 mm. Alternatively, the first lens 41 is spaced apart from the second lens 42 by an air layer of 10mm.

For example, the material of the second lens may be a type K4A optical glass, which has a refractive index between 1.359 and 1.661 and an abbe number between 55 and 67. Alternatively, the refractive index of the second lens is 1.51 and the abbe number is 61.1.

Illustratively, the radius of curvature of the first face of the third lens 43 is between 53.89mm and 65.87mm and the radius of curvature of the second face is between-86.33 mm and-70.63 mm. Optionally, the first face of the third lens 43 is glued to the second face of the second lens 42 with a radius of curvature equal to 59.883mm and the second face of the third lens 43 has a radius of curvature of-78.479 mm.

The thickness of the third lens 43 is, for example, between 9mm and 11 mm. Alternatively, the thickness of the third lens 43 is 10mm.

For example, the third lens 43 may be made of optical glass with a model H-ZPK, and has a refractive index of 1.413-1.727 and an abbe number of 64.17-78.43. Alternatively, the refractive index of the third lens 43 is 1.57, and the abbe number is 71.3.

Illustratively, the radius of curvature of the first face of the fourth lens 44 is between 120.46mm and 147.23mm and the radius of curvature of the second face is between-62.4 mm and-51.1 mm. Optionally, the radius of curvature of the first face of the fourth lens 44 is 133.842mm and the radius of curvature of the second face is-56.725 mm.

The thickness of the fourth lens 44 is between 9mm and 11mm, for example. Optionally, the thickness of the fourth lens 44 is 10mm.

Illustratively, the distance between the fourth lens 44 and the third lens 43 is between 13.5mm and 16.5 mm. Alternatively, the third lens 43 is spaced apart from the fourth lens 44 by an air layer of 15 mm.

Illustratively, the fourth lens 44 is made of optical glass having a type H-FK71A, and has a refractive index of 1.31 to 1.61 and an abbe number of 81.5 to 99.5. Alternatively, the fourth lens 44 has a refractive index of 1.46 and an abbe number of 90.5.

Illustratively, the radius of curvature of the first face of the fifth lens 45 is between-62.40 mm and-51.05 mm and the radius of curvature of the second face is between 367.8mm and 449.5 mm. Optionally, the first face of the fifth lens 45 is glued to the second face of the fourth lens 44, and the radii of curvature are each equal to-56.725 mm; the second radius of curvature of the fifth lens 45 is 408.619mm.

Illustratively, the thickness of the fifth lens 45 is between 0.9mm and 1.1 mm. Alternatively, the thickness of the fifth lens 45 is 1mm.

The fifth lens 45 is exemplified by an optical glass with a model D-LAF82L, and has a refractive index of 1.557 to 1.903 and an abbe number of 44 to 54. Alternatively, the refractive index of the fifth lens is 1.73 and the abbe number is 48.8.

Illustratively, the radius of curvature of the first face of the sixth lens 46 is between 78.17mm and 95.55mm and the radius of curvature of the second face is between 458.8mm and 560.8 mm. Optionally, the radius of curvature of the first face of the sixth lens 46 is 86.857mm and the radius of curvature of the second face is 509.802mm.

Illustratively, the sixth lens has a thickness of between 113mm and 138 mm. Optionally, the thickness of the sixth lens is 125.606mm.

Illustratively, the distance between the sixth lens 46 and the fifth lens 45 is between 13.5mm and 16.5 mm. Alternatively, the fifth lens 45 is spaced apart from the sixth lens 46 by an air layer of 15 mm.

Illustratively, the sixth lens is an optical glass with a model D-LAF50, and has a refractive index of between 1.593 and 1.947 and an abbe number of between 44.64 and 54.56. Alternatively, the refractive index of the sixth lens is 1.77 and the abbe number is 49.6.

Illustratively, the radius of curvature of the first face of the seventh lens 47 is between-38.92 mm and-31.84 mm and the radius of curvature of the second face is between 141.5mm and 172.9 mm. Optionally, the radius of curvature of the first face of the seventh lens 47 is-35.379 mm and the radius of curvature of the second face is 157.195mm.

Illustratively, the seventh lens 47 has a thickness of between 18mm and 22 mm. Optionally, the thickness of the seventh lens is 20mm.

Illustratively, the distance between the seventh lens 47 and the sixth lens 46 is between 13.5mm and 16.5 mm. Alternatively, the sixth lens 46 is disposed with an air layer spaced 15mm from the seventh lens 47.

Illustratively, the seventh lens is made of optical glass with a model number of H-ZF7LAGT, and has a refractive index of 1.629-1.991 and an Abbe number of 22.95-28.05. Alternatively, the seventh lens has a refractive index of 1.81 and an abbe number of 25.5.

Illustratively, the first face of the eighth lens 48 has a radius of curvature of between 141.5mm and 172.9mm and the second face has a radius of curvature of between-77.34 mm and-63.27 mm. Optionally, the first face of the eighth lens 48 is glued with the second face of the seventh lens 47 and the radius of curvature is equal to 157.195mm; the radius of curvature of the second face of the eighth lens 48 is-70.306 mm.

Illustratively, the thickness of the eighth lens 48 is between 71.9mm and 87.9 mm. Optionally, the eighth lens 48 has a thickness of 79.892mm.

Illustratively, the eighth lens is an optical glass with a model number of H-ZLAF55D, and has a refractive index of 1.647-2.013 and an Abbe number of 38.43-46.97. Alternatively, the refractive index of the eighth lens 48 is 1.83 and the abbe number is 42.7.

Illustratively, the radius of curvature of the first face of the ninth lens 49 is between 1120mm and 1369mm and the radius of curvature of the second face is between-257 mm and-210 mm. Optionally, the radius of curvature of the first face of the ninth lens 49 is 1244.451mm and the radius of curvature of the second face is-233.387 mm.

Illustratively, the thickness of the ninth lens 49 is between 115.5mm and 141.2 mm. Optionally, the thickness of the ninth lens 49 is 128.334mm.

Illustratively, the distance between the ninth lens 49 and the eighth lens 48 is between 18mm and 22 mm. Alternatively, the eighth lens 48 is disposed with an air layer of 20mm apart from the ninth lens 49.

Illustratively, the ninth lens is an optical glass with a model D-ZF93, and has a refractive index of 1.8 to 2.2 and an abbe number of 18.63 to 22.77. Alternatively, the ninth lens has a refractive index of 2.00 and an abbe number of 20.7.

It should be noted that the above description of the optical parameters of the imaging lens group is only an example given in this disclosure, and one or more lenses thereof may be adjusted in practical applications to suit practical requirements.

In order to explain the optical performance of the edge detection lens shown in the present disclosure, the image quality simulation experiment results of the edge detection lens are described below with reference to fig. 5 to 10.

In the simulation experiment, a linear array camera uses 5 mu m pixels, 16384 multiplied by 3 pixels, 81.92mm field of view, 2.5 mu m detection resolution of the system, -2 multiplied by lens magnification and 40mm field of view of an object. The simulation experiment can adopt a wafer to be tested with the thickness of 1mm.

First, a wafer edge surface detection lens composed of an edge detection lens and an imaging lens group will be described.

Fig. 5 shows an exemplary block diagram of a wafer edge surface inspection lens according to an embodiment of the present disclosure.

Fig. 6 shows a point diagram of a wafer edge facet inspection lens according to an embodiment of the present disclosure.

Fig. 7 shows an optical modulation function curve of a wafer edge facet inspection lens according to an embodiment of the present disclosure.

From the point chart, it can be seen that the relationship between the diffuse spots and the airy spots at the 3 imaging positions of the wafer edge surface inspection lens, the airy spots being spots formed at the focal point due to diffraction when the light source is imaged by the diffraction-limited lens. The more concentrated the diffuse spots are, the closer to an ideal optical system, and when the diffuse spots in the spot diagram are located within the range of the Airy spot circle, the image quality of the optical system can be considered to be good. As can be seen from fig. 6, the diffuse spots of the wafer edge surface inspection lens of the present disclosure at the 3 imaging positions are all within the range of the einzel spots, i.e., the imaging of the wafer edge surface inspection lens of the present disclosure has excellent image quality.

The optical modulation function curve is used to measure the ability to transfer contrast from an object to an image at a particular resolution, the closer the optical modulation function curve is to the diffraction limit, the better the image quality of the representative optical system. From the optical modulation function curves shown in fig. 7, it can be seen that the optical modulation function curves of the wafer edge surface inspection lens of the present disclosure are close to the diffraction limit, i.e., the image quality of the wafer edge surface inspection lens of the present disclosure is excellent.

The wafer surface inspection lens composed of the mirror, the surface inspection lens, and the imaging lens group will be described below.

Fig. 8 shows an exemplary block diagram of a wafer surface inspection lens according to an embodiment of the present disclosure.

Fig. 9 shows a point-column diagram of a wafer surface inspection lens according to an embodiment of the present disclosure.

Fig. 10 shows an optical modulation function curve of a wafer surface inspection lens according to an embodiment of the present disclosure.

According to the point diagram of the wafer surface inspection lens shown in fig. 9 and the optical modulation function curve of the wafer surface inspection lens shown in fig. 10, it can be known that, although the directions of the wafer surface and the wafer edge surface are different, the wafer surface and the wafer edge surface can be clearly imaged in one imaging device by the edge inspection lens provided by the disclosure, so that simultaneous inspection is realized and the imaging image quality is ensured.

In summary, the present disclosure provides a compound lens that combines with a multiplexed imaging lens set and a mirror to form an edge detection lens. The compound lens comprises an edge detection lens in a first caliber range and a surface detection lens in a second caliber range, wherein the curvature radius of the edge detection lens is different from that of the surface detection lens, so that the edge detection lens and the imaging lens group form a detection lens of the edge surface of the wafer. The reflector arranged above the upper surface of the wafer to be detected and/or below the lower surface of the wafer to be detected can reflect detection light rays on the surface of the wafer to the surface detection lens, so that the reflector, the surface detection lens and the imaging lens group form a detection lens on the surface of the wafer. The design of different curvature radiuses of the compound lens can enable the edge detection lens to have different object space working distances at different caliber positions, so that the edge detection lens can simultaneously realize clear imaging of three directions of the wafer edge, and can simultaneously detect the three directions of the wafer edge. Compared with the detection system in the prior art, the optical path prism and the image processing equipment are saved, and the volume and the cost of the detection system are further reduced.

The disclosed embodiments also provide an edge detection system including an image detection device, an imaging device, and an edge detection lens as described in any of the foregoing embodiments.

Wherein the imaging device is configured to: forming a wafer surface image and a wafer edge image according to detection light rays in the edge detection lens respectively, and sending the wafer surface image and the wafer edge image to image detection equipment; wherein, detect light and include: the detection light of the surface of the wafer to be detected and the detection light of the edge surface of the wafer to be detected.

The image detection device is configured to: and performing defect detection according to the wafer surface image and the wafer edge image sent by the imaging equipment, and outputting an edge detection result of the wafer to be detected.

It should be noted that, one or more compound lenses 4 may be adopted in the edge detection lens, and the object distances between the wafer edge surface and the wafer surface are finely adjusted by combining the compound lenses 4 with different optical parameters, so that the object distances are consistent, thereby ensuring the definition of the wafer surface image and the wafer edge image in the imaging device.

While various embodiments of the present disclosure have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous modifications, changes, and substitutions will occur to those skilled in the art without departing from the spirit and scope of the present disclosure. It should be understood that various alternatives to the embodiments of the disclosure described herein may be employed in practicing the disclosure. The appended claims are intended to define the scope of the disclosure and are therefore to cover all equivalents or alternatives falling within the scope of these claims.

Claims (10)

1. An edge detection lens, comprising:

a compound lens (3) comprising: an edge detection lens (31) within a first aperture range and a surface detection lens (32) within a second aperture range; the edge detection lens (31) is a meniscus negative lens, the surface detection lens (32) is a meniscus positive lens, the upper limit value of the first aperture range is smaller than or equal to the lower limit value of the second aperture range, and the curvature radius of the edge detection lens (31) is different from the curvature radius of the surface detection lens (32);

an imaging lens group (4);

the reflecting mirror (2) is arranged above the upper surface of the wafer (1) to be detected and/or below the lower surface of the wafer (1) to be detected, and is used for reflecting detection light rays on the surface of the wafer to be detected to the surface detection lens (32) and transmitting the detection light rays to the imaging lens group (4) through the surface detection lens (32); the detection light of the edge surface of the wafer to be detected is transmitted to the imaging lens group (4) through the edge detection lens (31).

2. The edge detection lens of claim 1, wherein,

the first surface of the edge detection lens (31) faces the wafer (1) to be detected, and the absolute value of the curvature radius of the first surface of the edge detection lens (31) is smaller than that of the second surface;

the first surface of the surface detection lens (32) faces the wafer (1) to be detected, and the absolute value of the curvature radius of the first surface of the surface detection lens (32) is smaller than that of the second surface.

3. The edge detection lens of claim 1, wherein,

the lower limit value of the first aperture range is 0mm, and the upper limit value is between 10mm and 15 mm;

the lower limit value of the second caliber range is equal to the upper limit value of the first caliber range, and the upper limit value is greater than or equal to 50mm.

4. The edge detection lens of claim 2, wherein,

the radius of curvature of the first face of the edge detection lens (31) is between-44 mm and-36 mm;

the radius of curvature of the second face of the edge detection lens (31) is between-66 mm and-54 mm;

the radius of curvature of the first face of the surface detection lens (32) is between 50.4mm and 61.6 mm;

the radius of curvature of the second face of the surface detection lens (32) is between 50.4mm and 61.6 mm.

5. The edge detection lens of claim 4, wherein,

the thickness of the edge detection lens (31) is between 35.34mm and 43.20 mm;

the thickness of the surface detection lens (32) is between 36mm and 44 mm.

6. The edge detection lens as claimed in claim 4 or 5, wherein,

the refractive index of the edge detection lens (31) is between 1.692 and 2.068, and the Abbe number is between 37 and 45;

the refractive index of the surface detection lens (32) is between 1.692 and 2.068, and the Abbe number is between 37 and 45.

7. The edge detection lens as claimed in claim 4 or 5, wherein,

the distance between the compound lens (3) and the wafer (1) to be tested is between 36mm and 44 mm.

8. The edge detection lens of claim 1, wherein,

the imaging lens group (4) includes:

a first lens (41) which is a meniscus negative lens; the first surface of the first lens faces the second surface of the edge detection lens, and the absolute value of the curvature radius of the first surface of the first lens is smaller than that of the second surface;

a second lens (42) which is a biconcave lens;

a third lens (43) which is a biconvex lens; the third lens is glued with the second lens;

a fourth lens (44) which is a biconvex lens;

a fifth lens (45) which is a biconcave lens; the fifth lens is glued with the fourth lens;

a sixth lens (46) which is a meniscus positive lens; the first surface of the sixth lens faces the fifth lens, and the absolute value of the curvature radius of the first surface of the sixth lens is smaller than that of the second surface;

a seventh lens (47) which is a biconcave lens;

an eighth lens (48) which is a biconvex lens; the eighth lens is glued with the seventh lens;

the ninth lens (49) is a biconvex lens.

9. The edge detection lens of claim 8, further comprising:

the radius of curvature of the first face of the first lens (41) is between-37.07 mm and-30.33 mm;

the radius of curvature of the second face of the first lens (41) is between-50.42 mm and-41.25 mm;

the radius of curvature of the first face of the second lens (42) is between-415.71 mm and-340.13 mm;

the second face of the second lens (42) has a radius of curvature of between 53.89mm and 65.87 mm;

the radius of curvature of the first face of the third lens (43) is between 53.89mm and 65.87 mm;

the radius of curvature of the second face of the third lens (43) is between-86.33 mm and-70.63 mm;

the radius of curvature of the first face of the fourth lens (44) is between 120.46mm and 147.23 mm;

the radius of curvature of the second face of the fourth lens (44) is between-62.4 mm and-51.1 mm;

the radius of curvature of the first face of the fifth lens (45) is between-62.40 mm and-51.05 mm;

the radius of curvature of the second face of the fifth lens (45) is between 367.8mm and 449.5 mm;

the radius of curvature of the first face of the sixth lens (46) is between 78.17mm and 95.55 mm;

the radius of curvature of the second face of the sixth lens (46) is between 458.8mm and 560.8 mm;

the radius of curvature of the first face of the seventh lens (47) is between-38.92 mm and-31.84 mm;

the radius of curvature of the second face of the seventh lens (47) is between 141.5mm and 172.9 mm;

the radius of curvature of the first face of the eighth lens (48) is between 141.5mm and 172.9 mm;

the radius of curvature of the second face of the eighth lens (48) is between-77.34 mm and-63.27 mm;

the radius of curvature of the first face of the ninth lens (49) is between 1120mm and 1369 mm;

the radius of curvature of the second face of the ninth lens (49) is between-257 mm and-210 mm.

10. An edge detection system, comprising: image detection apparatus, imaging apparatus, and edge detection lens as claimed in any one of claims 1 to 9;

the imaging device is configured to: forming a wafer surface image and a wafer edge image according to the detection light rays in the edge detection lens, and sending the wafer surface image and the wafer edge image to the image detection equipment; wherein, the detecting light includes: detecting light rays of the surface of the wafer to be detected and detecting light rays of the edge surface of the wafer to be detected;

the image detection device is configured to: and performing defect detection according to the wafer surface image and the wafer edge image sent by the imaging equipment, and outputting an edge detection result of the wafer to be detected.

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