CN114184138A - Detection device and detection method - Google Patents
Detection device and detection method Download PDFInfo
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- CN114184138A CN114184138A CN202010857187.2A CN202010857187A CN114184138A CN 114184138 A CN114184138 A CN 114184138A CN 202010857187 A CN202010857187 A CN 202010857187A CN 114184138 A CN114184138 A CN 114184138A
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- 238000001514 detection method Methods 0.000 title claims abstract description 126
- 238000003384 imaging method Methods 0.000 claims abstract description 144
- 238000005286 illumination Methods 0.000 claims abstract description 91
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- 238000012538 light obscuration Methods 0.000 description 5
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- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
- F21S2/00—Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction
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- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
- H01L22/10—Measuring as part of the manufacturing process
- H01L22/12—Measuring as part of the manufacturing process for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions
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Abstract
The application discloses a detection device and a detection method. The detection device comprises: an illumination assembly and an imaging assembly; the lighting assembly includes: a dome assembly; the imaging assembly includes: an imaging lens and a detector; when illuminated, the dome assembly is used to illuminate the object to be tested. The dome assembly is located to one side of the optical axis of the imaging assembly and is recessed in a direction away from the optical axis. The imaging lens is used for collecting the light reflected and/or scattered by the object to be detected and providing the light to the detector; the detector is used for forming a detection image of the object to be detected according to the light collected by the imaging lens. Due to the fact that the dome assembly can provide abundant illumination directions, various types of areas of the object to be detected can be illuminated abundantly, and imaging detection of the various types of areas is facilitated. Therefore, the detection accuracy of the object to be detected is improved, the angle of the object to be detected is prevented from being adjusted or the irradiation angle is prevented from being changed, and the detection efficiency and the detection amount are improved.
Description
Technical Field
The present disclosure relates to the field of detection and illumination technologies, and in particular, to a detection apparatus and a detection method.
Background
In the technical fields of semiconductors, terminals and the like, the shape of a product has high requirements, so strict detection is required. When detecting the shape of an object to be detected, if the ambient light is weak, the object to be detected generally needs to be illuminated. Taking a wafer as an example, the wafer generally includes a flat region (flat), a sloped region (level), and an open region (notch).
At present, when a wafer is detected, oblique incident bright field illumination is often performed on the wafer. However, since such an illumination method is difficult to irradiate the opening area, it is difficult to accurately detect the opening area of the wafer. In addition, it is difficult to provide sufficient light to the transition region between the flat region and the sloped region, which easily causes inconsistency in detected data. Therefore, the detection amount is reduced, and the detection accuracy is low.
Disclosure of Invention
Based on the above problems, the present application provides a detection apparatus and a detection method to improve the detection accuracy of an object to be detected and improve the detection amount.
The embodiment of the application discloses the following technical scheme:
in a first aspect, the present application provides a detection apparatus comprising: an illumination assembly and an imaging assembly; the lighting assembly includes: a dome assembly; the imaging assembly includes: an imaging lens and a detector;
when the dome assembly is lightened, the dome assembly is used for illuminating the object to be tested; the dome assembly is located on one side of the optical axis of the imaging assembly and is concave in a direction away from the optical axis;
the imaging lens is used for collecting the light reflected and/or scattered by the object to be detected and providing the light to the detector;
the detector is used for forming a detection image of the object to be detected according to the light collected by the imaging lens.
Optionally, the dome assembly is part of a sphere, the centre of the sphere of the dome assembly being located on the optical axis of the imaging assembly.
Optionally, the intersection point of the optical axis of the imaging assembly and the focal plane of the imaging assembly is the imaging field center of the imaging assembly; the distance between the imaging view field center and the sphere center is smaller than or equal to half of the thickness of the object to be detected.
Optionally, the dome assembly has a light emitting spherical radius in the interval 40mm to 60mm and an angle in the sagittal plane of the dome assembly in the interval 90 ° to 150 °.
Optionally, the lighting assembly further comprises: a coaxial assembly; the coaxial assembly includes: a coaxial light source; the imaging assembly further comprises a beam splitter, wherein light emitted by the coaxial light source reaches the surface of the object to be detected after being reflected by the beam splitter, and light returned by the object to be detected reaches the detector after being transmitted by the beam splitter; or the light emitted by the coaxial light source reaches the surface of the object to be detected after being transmitted by the beam splitter, and the light returned by the object to be detected reaches the detector after being reflected by the beam splitter; .
Optionally, the coaxial light source is a fiber light source or an LED light source.
Optionally, the light emitted by the coaxial light reaches the surface of the object to be detected after being reflected by the beam splitter, and the light returned by the object to be detected reaches the detector after being transmitted by the beam splitter; the coaxial assembly further comprises: and the extinction element is used for absorbing the light emitted by the coaxial light source and transmitted by the beam splitter.
Optionally, the fiber optic light source comprises: the device comprises a light box, a coupling optical fiber and a coupling lens, wherein the light emitting surface of the coupling optical fiber is located on a first focal plane of the coupling lens, and at least one point on the surface of the object to be detected is located on a second focal plane of the coupling lens.
Optionally, the focal length of the coupling lens is greater than the working distance of the imaging lens.
Optionally, the lighting assembly further comprises: the first lighting assembly; when the first illumination assembly is lightened, the first illumination assembly is used for dark field illumination of the object to be measured; the light-emitting direction of the first illuminating assembly and the optical axis of the imaging assembly form an acute included angle.
Optionally, the first lighting assembly comprises: a first subassembly, a second subassembly; the light emitting directions of the first sub-assembly and the second sub-assembly are different.
Optionally, the light exit direction of the first sub-assembly, the light exit direction of the second sub-assembly, and the optical axis of the imaging assembly are located on the same plane, and the light exit direction of the first sub-assembly and the light exit direction of the second sub-assembly are symmetric with respect to the optical axis of the imaging assembly; the dome assembly is located to one side of the plane.
Optionally, the first sub-assembly and the second sub-assembly are both fibre optic light sources.
In a second aspect, the present application provides a detection method, which is applied to any one of the detection apparatuses in the first aspect, and the method includes:
illuminating the area to be measured of the object to be measured by utilizing the illumination assembly;
collecting light reflected and/or scattered by the object to be detected by using the imaging lens, and providing the light to the detector;
and forming a detection image of the object to be detected by using the detector according to the light collected by the imaging lens.
Optionally, the intersection point of the optical axis of the imaging assembly and the focal plane of the imaging assembly is the imaging field center of the imaging assembly; the distance between the imaging field center and the spherical center of the sphere where the dome assembly is located is smaller than or equal to the thickness of the object to be measured;
before the illumination assembly is used for illuminating the region to be measured of the object to be measured, the method further comprises the following steps: and enabling the area to be measured of the object to be measured to cover the center of the imaging view field.
Optionally, the object to be tested is a wafer to be tested, and the region to be tested is an edge region of the wafer to be tested; the edge area of the wafer to be tested comprises: a flat region, a sloped region, and an open region;
the lighting assembly is used for lighting the area to be tested of the object to be tested, and the method specifically comprises one or a combination of the following steps:
illuminating the coaxial assembly, the dome assembly and the first illumination assembly, and performing imaging detection on the flat area, the inclined area and the opening area through the detection device to obtain bright field images of the flat area, the inclined area and the opening area;
the coaxial assembly is lightened, the detection device is used for imaging and detecting the flat area to obtain a bright field image of the flat area, and imaging and detecting the inclined area and the opening area to obtain a dark field image of the inclined area and the opening area;
the dome assembly is lightened, the inclined area and the opening area are detected and imaged through the detection device, bright field images of the inclined area and the opening area are obtained, imaging detection is carried out on the flat area, and a dark field image of the flat area is obtained;
the coaxial assembly and the first illuminating assembly are lightened, the inclined area and the opening area are subjected to imaging detection through the detecting device, and dark field images of the inclined area and the opening area are obtained; and illuminating the dome assembly and the first illumination assembly, and carrying out imaging detection on the flat area through the detection device to obtain a dark field image of the flat area.
Compared with the prior art, the method has the following beneficial effects:
the application provides a detection device includes: an illumination assembly and an imaging assembly; the lighting assembly includes: a dome assembly; the imaging assembly includes: an imaging lens and a detector; when illuminated, the dome assembly is used to illuminate the object to be tested. The dome assembly is located to one side of the optical axis of the imaging assembly and is recessed in a direction away from the optical axis. The imaging lens is used for collecting the light reflected and/or scattered by the object to be detected and providing the light to the detector; the detector is used for forming a detection image of the object to be detected according to the light collected by the imaging lens. Due to the fact that the dome assembly can provide abundant illumination directions, various types of areas of the object to be detected can be illuminated abundantly, and imaging detection of the various types of areas is facilitated. Therefore, the detection accuracy of the object to be detected is improved, the angle of the object to be detected is prevented from being adjusted or the irradiation angle is prevented from being changed, and the detection efficiency and the detection amount are improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.
Fig. 1 is a schematic structural diagram of a detection apparatus provided in an embodiment of the present application in a meridian plane;
fig. 2 is a schematic view of a detection device provided in an embodiment of the present application in a sagittal plane;
FIG. 3 is a schematic structural diagram of another detecting device provided in an embodiment of the present application in a meridian plane;
fig. 4 is a schematic diagram of an internal structure of a dark field optical fiber according to an embodiment of the present application;
fig. 5 is a schematic perspective view illustrating an edge of a wafer being detected by a detecting device according to an embodiment of the present disclosure;
FIG. 6 is a top view of the three-dimensional structure shown in FIG. 5;
FIG. 7 is a schematic view of a wafer flat area, a bevel area, and an open area;
FIG. 8 is a schematic diagram illustrating a simulation of illuminating and imaging a flat region, an open region and a tilted region of a wafer by using a detecting apparatus according to an embodiment of the present disclosure;
fig. 9 is a flowchart of a detection method according to an embodiment of the present application.
Detailed Description
As described above, the current detection device is difficult to provide sufficient light for various types of regions of the object to be detected, resulting in low detection amount and poor detection accuracy. Based on this problem, the inventors have studied and provided a detection apparatus and a detection method in the present application. Among the detection device, the dome subassembly throws light on the determinand as lighting assembly, can provide very abundant illumination direction for the determinand to be convenient for provide sufficient lighting condition to the regional detection of the multiple type of determinand, promote the detection volume and detect the accuracy.
In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Device embodiment
The detection device provided by the application comprises: an illumination assembly and an imaging assembly. The illumination assembly is used for illuminating the object to be detected, and the imaging assembly is used for imaging and detecting the object to be detected under the illumination condition provided by the illumination assembly. The detection device is described in detail below with reference to the accompanying drawings.
Referring to fig. 1, the figure is a schematic structural diagram of a detection apparatus provided in an embodiment of the present application in a meridian plane. Fig. 2 is a schematic view of the detector shown in fig. 1 in a sagittal plane. In the detection device shown in fig. 1 and 2, the illumination assembly comprises: a dome assembly 100; the imaging assembly includes: an imaging lens 200 and a detector 300.
The dome assembly 100 is located on one side of the optical axis of the imaging assembly, and the dome assembly is recessed towards the direction away from the optical axis, so that no hole needs to be formed in the dome assembly 100, and the imaging lens 200 can image an object to be measured within the field of view of the imaging lens 200 under the condition that the dome assembly 100 is not interfered and blocked. In order to ensure the brightness uniformity of the image, the imaging lens 200 may specifically adopt an object-side telecentric lens.
When illuminated, the dome assembly 200 is used to illuminate the test object. Since the dome assembly 100 is capable of providing light in a variety of illumination directions, various types of areas of the test object can be illuminated.
The imaging lens 200 is used to collect light reflected and/or scattered by the object to be measured, refract the light beam and provide the light beam to the detector 300.
The detector 300 may be a photoelectric detector for performing photoelectric conversion to form a detection image of the object.
In the embodiment of the present application, since the dome assembly 100 can provide a very rich illumination direction, a rich illumination can be performed on various types of areas of the object to be detected, which facilitates imaging detection on these various types of areas. Therefore, the detection accuracy of the object to be detected is improved, the angle of the object to be detected is prevented from being adjusted or the irradiation angle is prevented from being changed, and the detection efficiency and the detection amount are improved.
the center of the sphere of the dome assembly 100 is located on the optical axis of the imaging assembly, i.e., the optical axis of the imaging assembly passes through the center of the sphere in which the dome assembly 100 is located.
When the object to be detected is detected, the object to be detected is placed on the working plane, the upper surface of the object to be detected is overlapped with the focal plane of the imaging assembly, and the intersection point of the optical axis of the imaging assembly and the focal plane of the imaging assembly is the imaging view field center of the imaging assembly. In practical application, the distance between the center of the imaging field of view and the center of the sphere is very close, and for a thin object to be measured, the center of the sphere and the center of the imaging field of view may coincide. For an object to be measured with a certain thickness, the center of sphere can be located at the center of the thickness of the object to be measured, that is, the distance between the center of sphere and the center of the imaging view field is half of the thickness of the object to be measured. Therefore, in practical application, the distance between the center of the sphere and the center of the imaging field of view is less than or equal to half of the thickness of the object to be measured.
In one possible implementation, the dome assembly 100 has a light emitting spherical radius between 40mm-60mm, for example 50 mm; the dome assembly 100 is angled between 90 deg. and 150 deg. in the sagittal plane, for example 120 deg., as shown in figure 2.
In the detection apparatus provided in the embodiment of the present application, the illumination assembly may further include, on the basis of including the dome assembly: a coaxial assembly. The coaxial assembly includes: a coaxial light source, the imaging assembly further comprising a beam splitter. The following two use possibilities are included:
(1) light emitted by the coaxial light source reaches the surface of the object to be detected after being reflected by the beam splitter, and light returned by the object to be detected reaches the detector 300 after being transmitted by the beam splitter.
(2) Light emitted by the coaxial light source reaches the surface of the object to be detected after being transmitted by the beam splitter, and light returned by the object to be detected reaches the detector 300 after being reflected by the beam splitter.
The two cases (1) and (2) can be regarded as the respective optical path transmission directions after the positions of the coaxial light source and the imaging component are mutually replaced. The drawing only illustrates the device layout of the case (1). The optical axis of the imaging assembly refers specifically to the central axis of the light beam collected by the imaging assembly. The components on the collection path between the detector 300 and the object are part of the imaging assembly, and thus the beam splitter is also part of the imaging assembly.
In the step (1), the object to be measured is illuminated by the reflected light beam, and in the scene, the reflected light beam split by the beam splitter is coaxial with the optical axis of the imaging component.
In the step (2), the object to be measured is illuminated by the transmitted light beam, and in the scene, the transmitted light beam split by the beam splitter is coaxial with the optical axis of the imaging component.
The coaxial assembly may also be referred to as an outer coaxial light source, also for illumination. When the coaxial assembly is lighted, the coaxial assembly is particularly used for bright field illumination of an object to be measured. The coaxial light source may specifically be a fiber optic light source or an LED light source.
Two implementations of the coaxial assembly are described below in conjunction with the figures.
Referring to fig. 1 and 2, a first implementation of the coaxial assembly is shown from two views, respectively. In a first implementation, a coaxial assembly includes: a lamp box (not shown), a coupling fiber 400, a coupling lens 500, a first light splitting element 600, and a first light extinction element 700.
One end of the coupling fiber 400 is optically connected to the lamp box, and the other end is optically connected to the coupling lens 500. The coupling optical fiber 400 transmits the light provided from the lamp box to the coupling lens 500.
The first beam splitting element 600 is used for receiving the light beam passing through the coupling lens 500. The first light splitting element 600 is used for reflecting and transmitting the received light beam, the reflected light is emitted to the object to be measured, and the transmitted light is emitted to the first light extinction element 700. The first extinction element 700 is located on a side of the first light splitting element 600 through which the light beam is transmitted, and specifically, the first extinction element 700 may be closely attached to the side of the first light splitting element 600 through which the light beam is transmitted. The first light extinction element 700 is used to absorb and eliminate the received light (i.e., the transmitted light of the first light splitting element 600).
In one possible implementation, the light emitting surface of the coupling fiber 400 is located in a first focal plane of the coupling lens 500, and at least one point on the surface of the object to be measured is located in a second focal plane of the coupling lens 500. The first focal plane is a front focal plane of the coupling lens 500, and the second focal plane is a rear focal plane of the coupling lens 500. By adopting the Kohler illumination mode, higher illumination uniformity can be obtained, and the illumination uniformity is not influenced by the dirt or processing flaws on the light emitting surface of the optical fiber.
The focal length of the coupling lens 500 is greater than the working distance of the imaging lens 200, and the difference between the focal length of the coupling lens 500 and the working distance of the imaging lens 200 is smaller than a preset second threshold. This facilitates the layout of the components within the inspection device.
Fig. 3 is a schematic structural diagram of another detection apparatus provided in an embodiment of the present application in a meridian plane. This figure illustrates a second implementation of a coaxial assembly. As shown, the coaxial assembly includes: a bright field light emitting diode 800, a second light splitting element 900 and a second light extinction element 1000. The second light splitting element 900 has substantially the same function as the first light splitting element 600, and both have reflection and refraction functions.
The light beam emitted from the bright field led 800 is split by the second light splitting element 900, wherein the reflected light is provided to the object to be measured, and the transmitted light is provided to the second light extinction element 1000. The second extinction member 1000 functions substantially the same as the first extinction member 700. Specifically, the second extinction element 1000 may be attached to a surface of the second beam splitting element 900 through which the light beam is transmitted. The second extinction element 1000 is used to absorb and eliminate the received light (i.e., the transmitted light of the second light splitting element 900).
The first light splitting element 600 and the second light splitting element 900 may be a light splitting prism or a light splitting sheet. The splitting ratio of the first and second splitting elements 600 and 900 may be 50%: 50%, i.e., semi-reflective and semi-transmissive. Thus, a high light efficiency can be obtained.
As mentioned previously, the optical axis of the coaxial assembly is coaxial with the optical axis of the imaging assembly. In the first and second implementations of the coaxial assembly, since the respective light reflecting and transmitting actions of the first light splitting element 600 and the second light splitting element 900 are known, the reflected light is specifically provided to the object to be measured for illumination, and the coaxial optical axis specifically means that the optical axis of the reflection light path from the coaxial assembly to the object to be measured is coaxial with the optical axis of the imaging assembly. That is, in the first implementation, the optical axis of the optical path from the first light splitting element 600 to the object to be measured is coaxial with the optical axis of the imaging component; in the second implementation, the optical axis of the optical path from the second light splitting element 900 to the object to be measured is coaxial with the optical axis of the imaging component.
In the second implementation manner of the coaxial assembly, the bright field light emitting diode 800 is used as a light source in the coaxial assembly, so that in the provided detection device, the integration level of the illumination assembly is improved, and the reduction of the overall volume of the detection device is facilitated.
In some cases, dark field illumination and dark field detection of the object to be measured by means of the detection device are also required. For this reason, in the detection device provided in the embodiments of the present application, the illumination assembly may further include a first illumination assembly. When the first illumination assembly is lightened, the first illumination assembly is used for dark field illumination of the object to be measured.
In the embodiment of the application, in order to perform sufficient dark field illumination on the measured area of the object to be measured, the first illumination assembly can provide at least two different illumination directions. For example, the first illumination assembly may include at least two lights providing different illumination directions, and the light exit direction of the first illumination assembly has an acute angle with the optical axis of the imaging assembly. The first illumination assembly may be either a fiber optic light source or an LED light source.
The first illumination assembly may include a first subassembly and a second subassembly, both of which are fiber optic light sources in the examples below.
In one possible implementation, the first illumination assembly includes a first dark field optical fiber 301 and a second dark field optical fiber 302 shown in fig. 3. The first dark field optical fiber 301 and the second dark field optical fiber 302 may be connected to a dark field light box (not shown), wherein a first end of the optical fibers is optically connected to the dark field light box, and a second end of the optical fibers is used for emitting a light beam to a surface of an object to be measured. The illumination direction provided by the first dark field fiber 301 to the object to be measured is different from the illumination direction provided by the second dark field fiber 302 to the object to be measured.
The first dark field fiber 301 and the second dark field fiber 302 may be connected to the same dark field light box, for example, the dark field light box includes two output ports, and the two output ports are respectively connected to different dark field fibers. In addition, the first dark field optical fiber 301 and the second dark field optical fiber 302 can also be respectively connected with different dark field lamp boxes. For example, a first end of first dark field fiber 301 is optically connected to a first light box (not shown), and a first end of second dark field fiber 302 is optically connected to a second light box (not shown).
The light boxes to which the first dark field fiber 301 and the second dark field fiber 302 are connected may have different spectral divisions, e.g. 1 for blue and 1 for green light boxes. And flexible adjustment is performed according to different wafer processes. Different wafer processes result in different optical reflection properties of the surface: spectral reflectance differences, surface roughness differences, overall reflectance, etc. That is to say, in practical application, a suitable processing technology can be selected to process the wafer according to the requirement of the optical reflection characteristic, or a lamp box with a suitable spectrum can be selected according to the processing technology of the wafer. Thereby, the desired illumination and detection effects are achieved.
Fig. 4 illustrates an internal structure of a dark field optical fiber. As can be seen from fig. 4, the dark field optical fiber contains a cylindrical mirror inside, and the light emitting surface of the optical fiber is imaged on the surface of the wafer, so as to obtain the highest illumination. The optical axes of the first dark field fiber 301 and the second dark field fiber 302 may be coplanar with the illumination optical axis of the coaxial assembly (or the optical axis of the imaging assembly, or the imaging optical path), respectively. Optionally, the optical axes of the first dark field optical fiber 301 and the second dark field optical fiber 302 are at an acute angle, for example 70 °, to the optical axis of the imaging assembly.
In one possible implementation, the power of the first illumination assembly is higher than the power of the coaxial assembly, so that the first illumination assembly can provide a condition of high brightness dark field illumination.
In one possible implementation, the imaging lens 200 is at a working distance of 110mm, and the overall dimension of the coaxial assembly and the dome assembly in the direction of the optical axis is no more than 110 mm. Meanwhile, in consideration of the safety of the upper and lower pieces of the object to be measured (e.g. a wafer), the illumination distance of the first dark field fiber 301 and the second dark field fiber 302 is 70mm, and the minimum distance between the structures of the first dark field fiber 301 and the second dark field fiber 302 and the object to be measured is more than 24 mm. If the object to be measured is a wafer, the center of the field of view of the imaging lens 200 is located at a distance of 147.5mm from the center of the wafer in this embodiment.
In this embodiment, the detector 300 of the detection apparatus is a 3-line true color line scan detector, the length of the line scan array is perpendicular to the plane shown in fig. 1, and the scanning direction is the horizontal direction shown in fig. 1. The wafer rotates by taking the center of the wafer as the center, and the line scanning camera can image the whole edge of the wafer. Therefore, the effect of high-speed acquisition can be achieved, and the obtained image is a true color RGB image, so that multispectral defect identification can be conveniently carried out in the later period, and the identification rate is improved. According to the scanning direction of the line-scan camera, the meridional plane of bright field illumination is preferably coincident with the cross section of the dome assembly in the embodiment, so that the imaging uniformity is ensured.
Fig. 5 is a schematic perspective view illustrating an edge of a wafer being detected by a detecting device according to an embodiment of the present disclosure. Fig. 6 is a top view of the three-dimensional structure shown in fig. 5. In addition, the first lighting assembly may also be an annular LED light source.
For a scene using a wafer as a to-be-detected object, the to-be-detected wafer includes: flat area, sloped area, and open area. FIG. 7 is a schematic view of a wafer flat area, a bevel area, and an open area. In order to realize the illumination and detection of various types of areas, different illumination component combinations can be adopted for illumination respectively.
The detection device is used for bright field illumination and imaging detection of the flat area, the inclined area and the opening area when the coaxial assembly, the dome assembly and the first illumination assembly are simultaneously lighted;
when only the coaxial assembly is lighted, the detection device is used for carrying out bright field illumination and imaging detection on the flat area and carrying out dark field illumination and imaging detection on the inclined area and the opening area;
when only the dome assembly is lighted, the detection device is used for carrying out bright field illumination and imaging detection on the inclined area and the opening area and carrying out dark field illumination and imaging detection on the flat area;
when the coaxial assembly and the first illumination assembly are simultaneously lightened, the detection device is used for carrying out dark field illumination and imaging detection on the inclined area and the opening area;
the detection apparatus is used for dark field illumination and imaging detection of the flat zone when the dome assembly and the first illumination assembly are illuminated simultaneously.
According to the illumination and detection requirements of different areas of the detected object, the 5 illumination working schemes are adjusted according to the actual situation, the combination scheme is optimized, and the effects of fastest detection speed and highest defect detection sensitivity can be achieved. Fig. 8 is a simulation diagram illustrating illumination and imaging of a flat area, an open area and a tilted area of a wafer by using the inspection apparatus according to the embodiment of the present disclosure. As can be seen from fig. 8, illumination performed by the above illumination assembly combination can cover illumination of various areas of the wafer, thereby realizing effective detection of the wafer.
Method embodiment
Based on the device embodiment provided by the foregoing embodiment, correspondingly, the application further provides a detection method. As shown in fig. 9, a flow chart of a detection method is shown. The method is particularly used for realizing illumination and detection by utilizing the detection device provided by the device embodiment.
The detection method shown in fig. 9 includes:
step 901: illuminating the area to be measured of the object to be measured by utilizing the illumination assembly;
step 902: collecting light reflected and/or scattered by the object to be detected by using the imaging lens, and providing the light to the detector;
step 903: and forming a detection image of the object to be detected by using the detector according to the light collected by the imaging lens.
Due to the fact that the dome assembly can provide abundant illumination directions, various types of areas of the object to be detected can be illuminated abundantly, and imaging detection of the various types of areas is facilitated. Therefore, the detection accuracy of the object to be detected is improved, the angle of the object to be detected is prevented from being adjusted or the irradiation angle is prevented from being changed, and the detection efficiency and the detection amount are improved.
The intersection point of the optical axis of the imaging assembly and the focal plane of the imaging assembly is the imaging field center of the imaging assembly; the distance between the imaging field center and the spherical center of the sphere where the dome assembly is located is smaller than or equal to the thickness of the object to be measured;
before the step S901 is executed, the method may further include: and enabling the area to be measured of the object to be measured to cover the center of the imaging view field.
If the object to be measured is a wafer to be measured, the area to be measured of the object to be measured is an edge area of the wafer, and the edge area of the wafer to be measured comprises: a flat region, a sloped region, and an open region;
step 901 may specifically include one or a combination of the following steps:
illuminating the coaxial assembly, the dome assembly and the first illumination assembly, and performing imaging detection on the flat area, the inclined area and the opening area through the detection device to obtain bright field images of the flat area, the inclined area and the opening area;
the coaxial assembly is lightened, the detection device is used for imaging and detecting the flat area to obtain a bright field image of the flat area, and imaging and detecting the inclined area and the opening area to obtain a dark field image of the inclined area and the opening area;
the dome assembly is lightened, the inclined area and the opening area are detected and imaged through the detection device, bright field images of the inclined area and the opening area are obtained, imaging detection is carried out on the flat area, and a dark field image of the flat area is obtained;
the coaxial assembly and the first illuminating assembly are lightened, the inclined area and the opening area are subjected to imaging detection through the detecting device, and dark field images of the inclined area and the opening area are obtained; and illuminating the dome assembly and the first illumination assembly, and carrying out imaging detection on the flat area through the detection device to obtain a dark field image of the flat area.
It should be noted that, in the present specification, all the embodiments are described in a progressive manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the apparatus and system embodiments, since they are substantially similar to the method embodiments, they are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described embodiments of the apparatus and system are merely illustrative, and the units described as separate parts may or may not be physically separate, and the parts suggested as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
The above description is only one specific embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (16)
1. A detection device, comprising: an illumination assembly and an imaging assembly; the lighting assembly includes: a dome assembly; the imaging assembly includes: an imaging lens and a detector;
when the dome assembly is lightened, the dome assembly is used for illuminating the object to be tested; the dome assembly is located on one side of the optical axis of the imaging assembly and is concave in a direction away from the optical axis;
the imaging lens is used for collecting the light reflected and/or scattered by the object to be detected and providing the light to the detector;
the detector is used for forming a detection image of the object to be detected according to the light collected by the imaging lens.
2. The inspection device of claim 1, wherein the dome assembly is part of a sphere, the center of the dome assembly being located on the optical axis of the imaging assembly.
3. The detection apparatus according to claim 2, wherein the intersection point of the optical axis of the imaging assembly and the focal plane of the imaging assembly is the imaging field center of the imaging assembly; the distance between the imaging view field center and the sphere center is smaller than or equal to half of the thickness of the object to be detected.
4. The sensing device of claim 2, wherein the dome assembly has a light emitting spherical radius in the interval 40mm to 60mm and an angle in the sagittal plane in the interval 90 ° to 150 °.
5. The detection apparatus of any one of claims 1-4, wherein the illumination assembly further comprises: a coaxial assembly; the coaxial assembly includes: a coaxial light source; the imaging assembly further comprises a beam splitter, wherein light emitted by the coaxial light source reaches the surface of the object to be detected after being reflected by the beam splitter, and light returned by the object to be detected reaches the detector after being transmitted by the beam splitter; or the light emitted by the coaxial light source reaches the surface of the object to be detected after being transmitted by the beam splitter, and the light returned by the object to be detected reaches the detector after being reflected by the beam splitter; .
6. The detection device of claim 5, wherein the coaxial light source is a fiber optic light source or an LED light source.
7. The detection device according to claim 5, wherein the light emitted from the coaxial light is reflected by the beam splitter and reaches the surface of the object to be detected, and the light returned from the object to be detected is transmitted by the beam splitter and reaches the detector; the coaxial assembly further comprises: and the extinction element is used for absorbing the light emitted by the coaxial light source and transmitted by the beam splitter.
8. The detection device of claim 6, wherein the fiber optic light source comprises: the device comprises a light box, a coupling optical fiber and a coupling lens, wherein the light emitting surface of the coupling optical fiber is located on a first focal plane of the coupling lens, and at least one point on the surface of the object to be detected is located on a second focal plane of the coupling lens.
9. The detection apparatus according to claim 8, wherein the focal length of the coupling lens is greater than the working distance of the imaging lens.
10. The detection device of claim 5, wherein the illumination assembly further comprises: the first lighting assembly; when the first illumination assembly is lightened, the first illumination assembly is used for illuminating the object to be measured; the light-emitting direction of the first illuminating assembly and the optical axis of the imaging assembly form an acute included angle.
11. The detection apparatus of claim 10, wherein the first illumination assembly comprises: a first subassembly, a second subassembly; the light emitting directions of the first sub-assembly and the second sub-assembly are different.
12. The detecting device according to claim 11, wherein the light exiting direction of the first sub-assembly, the light exiting direction of the second sub-assembly and the optical axis of the imaging assembly are located on the same plane, and the light exiting direction of the first sub-assembly and the light exiting direction of the second sub-assembly are symmetrical with respect to the optical axis of the imaging assembly; the dome assembly is located to one side of the plane.
13. The detection device of claim 11, wherein the first and second subassemblies are each a fiber optic light source.
14. A method of testing, using the test device of any one of claims 1-13, the method comprising:
illuminating the area to be measured of the object to be measured by utilizing the illumination assembly;
collecting light reflected and/or scattered by the object to be detected by using the imaging lens, and providing the light to the detector;
and forming a detection image of the object to be detected by using the detector according to the light collected by the imaging lens.
15. The detection method according to claim 14, wherein the intersection point of the optical axis of the imaging assembly and the focal plane of the imaging assembly is the imaging field center of the imaging assembly; the distance between the imaging field center and the spherical center of the sphere where the dome assembly is located is smaller than or equal to the thickness of the object to be measured;
before the illumination assembly is used for illuminating the region to be measured of the object to be measured, the method further comprises the following steps: and enabling the area to be measured of the object to be measured to cover the center of the imaging view field.
16. The inspection method according to claim 14 or 15, wherein the object to be inspected is a wafer to be inspected, and the area to be inspected is an edge area of the wafer to be inspected; the edge area of the wafer to be tested comprises: a flat region, a sloped region, and an open region;
the lighting assembly is used for lighting the area to be tested of the object to be tested, and the method specifically comprises one or a combination of the following steps:
illuminating the coaxial assembly, the dome assembly and the first illumination assembly, and performing imaging detection on the flat area, the inclined area and the opening area through the detection device to obtain bright field images of the flat area, the inclined area and the opening area;
the coaxial assembly is lightened, the detection device is used for imaging and detecting the flat area to obtain a bright field image of the flat area, and imaging and detecting the inclined area and the opening area to obtain a dark field image of the inclined area and the opening area;
the dome assembly is lightened, the inclined area and the opening area are detected and imaged through the detection device, bright field images of the inclined area and the opening area are obtained, imaging detection is carried out on the flat area, and a dark field image of the flat area is obtained;
the coaxial assembly and the first illuminating assembly are lightened, the inclined area and the opening area are subjected to imaging detection through the detecting device, and dark field images of the inclined area and the opening area are obtained; and illuminating the dome assembly and the first illumination assembly, and carrying out imaging detection on the flat area through the detection device to obtain a dark field image of the flat area.
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