CN110849900A

CN110849900A - Wafer defect detection system and method

Info

Publication number: CN110849900A
Application number: CN201810955348.4A
Authority: CN
Inventors: 陈鲁; 黄有为; 崔高增; 王天民
Original assignee: Institute of Microelectronics of CAS
Current assignee: Institute of Microelectronics of CAS; Skyverse Ltd
Priority date: 2018-08-21
Filing date: 2018-08-21
Publication date: 2020-02-28

Abstract

The invention discloses a wafer defect detection device and a wafer defect detection method. The detection system comprises: a detection component configured to generate a detection spot corresponding to a specified angle of incidence based on the received detection beam; the signal collection assembly is configured to collect signal light generated by the object to be detected under the action of the detection light spot, and further generate detection information corresponding to the incident angle; and the processor assembly is configured to enable the detection assembly to sequentially generate detection light spots at a first incidence angle and a second incidence angle, and further determine defect characteristic information on the detected object at least based on the first detection information and the second detection information corresponding to the first incidence angle and the second incidence angle. By adopting the technical scheme of the invention, the moving time of the wafer is saved, and the detection speed can be obviously increased.

Description

Wafer defect detection system and method

Technical Field

The invention belongs to the field of detection, and particularly relates to a system and a method for detecting wafer defects.

Background

The wafer defect detection means detecting whether the wafer has defects such as grooves, particles, scratches and the like and defect positions. The wafer defect detection is very widely applied: on one hand, as a chip substrate, defects existing on a wafer can cause failure of an expensive process manufactured on the wafer, defect detection is usually carried out on the wafer production to ensure the product percent of pass, and the wafer user also needs to determine the cleanness degree of the wafer before use to ensure the product percent of pass; on the other hand, because the control of the additional pollution in the processing process by the semiconductor processing is very strict, and the difficulty of directly monitoring the additional pollution in the processing process is higher, people usually judge the additional pollution degree of the process by comparing defects before and after the wafer bare chip processing. Therefore, various means for detecting wafer defects have been sought.

The current common wafer defect detection methods mainly comprise two categories, namely electron beam detection and optical detection. Due to the extreme wavelength of electron wave, electron beam inspection can image directly and has resolution of 1-2 nm, however, it requires long time for inspection and high vacuum environment for inspection, and is usually only used for sampling inspection of a few critical circuit links. The optical detection is a generic term for a method for realizing detection by utilizing the interaction between light and a chip, and the basic principle is to judge whether a defect exists or not and the size of the defect by scanning and detecting whether incident light and defect scattered light exist or not and the intensity of the incident light and the defect scattered light.

Disclosure of Invention

The present invention provides a system and a method for detecting multiple incident angles of a wafer.

First, the present invention provides a detection system, which includes: a detection component configured to generate a detection spot corresponding to a specified angle of incidence based on the received detection beam; the signal collection component is configured to collect signal light generated by the object to be detected under the action of the detection light spot, and further generate detection information corresponding to the incidence angle; and a processor component configured to cause the detection component to sequentially generate the detection light spot at a first incident angle and a second incident angle, and further determine defect characteristic information on the object to be detected based on at least first and second detection information corresponding to the first and second incident angles, wherein the processor component is further configured to cause the detection component to: detecting the object to be detected by a first detection path based on the first incidence angle; and detecting the object to be detected with a second detection path corresponding to the first detection path based on the second incident angle.

The invention also provides a detection method, which comprises the following steps: generating a first detection light beam, wherein the first detection light beam has a first incident angle, the first detection light beam forms a first detection light spot on the surface of the object to be detected, and the first detection light spot comprises a first detection area; performing first scanning on a region to be detected of the object to be detected through the first detection light beam, performing first detection on the region to be detected, and acquiring first detection information generated after the first detection light beam is acted on the object to be detected; generating a second detection light beam, wherein the second detection light beam has a second incident angle, the second incident angle is different from the first incident angle, the second detection light beam forms a second detection light spot on the surface of the region to be detected of the object to be detected, the second detection light spot comprises a second detection region, and the center of the second detection region is the same as the center of the first detection region; after the first scanning, taking the end point of the first scanning as a starting point, performing second scanning on the region to be detected of the detected object through the second detection light beam, performing second detection on the region to be detected, and acquiring second detection information; and acquiring the defect characteristic information of the detected object according to the first detection information and the second detection information.

By adopting the technical scheme of the invention, the moving time of the wafer is saved, and the positioning error is reduced because the wafer is prevented from moving to the starting point again, so that the algorithm of matching and aligning the two detection results is much simpler, and the detection speed can be obviously increased. In addition, by using the technical scheme of the invention, different particles can be detected by using the light source with the same wavelength.

Drawings

Embodiments are shown and described with reference to the drawings. These drawings are provided to illustrate the basic principles and thus only show the aspects necessary for understanding the basic principles. The figures are not to scale. In the drawings, like reference numerals designate similar features.

FIG. 1 is a diagram of an inspection system architecture according to an embodiment of the present invention;

FIG. 2 is a diagram of an optical architecture of an inspection system according to an embodiment of the present invention;

FIG. 3a is a flowchart of a first detection method according to an embodiment of the present invention;

FIG. 3b is a flowchart of a second detection method according to the embodiment of the present invention;

FIG. 4 is a diagram illustrating a detection path according to an embodiment of the present invention;

FIG. 5a is a schematic view of a signal collection assembly according to an embodiment of the present invention;

FIG. 5b is a schematic diagram of an image-like collection principle according to an embodiment of the present invention.

Detailed Description

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof. The accompanying drawings illustrate, by way of example, specific embodiments in which the invention may be practiced. The illustrated embodiments are not intended to be exhaustive of all embodiments according to the invention. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

First, terms related to the present invention will be explained. The detection light beam refers to the light beam which is generated by the light source component and finally forms the detection light spot, and the optical component aims to adjust the detection light beam so as to form the detection light spots corresponding to different incidence angles. The incident angle is an angle between the detection beam and a normal direction of a surface of an object to be detected (e.g., a wafer). The detection region is a region corresponding to the signal light received by the detector, for example, a portion with relatively strong light intensity in the irradiation region of the detection light spot, and the portion is received by the detector to analyze the object to be detected.

The inventors have found through extensive studies that the signal light collection angle range (normal collection or non-normal collection) depends on the incident light angle (e.g., normal incidence or oblique incidence, and corresponding oblique incidence angle). There are various implementations of the light scattering method, including: (1) normal incidence illumination normal collection (2), normal incidence illumination non-normal collection (3), oblique incidence illumination normal collection (4) and oblique incidence illumination non-normal collection. Depending on the incident light angle and the type of defect, the scattered light will exhibit different distribution characteristics.

In particular, for convex-like defects (e.g., particles) distributed on the wafer, when light is normally incident, the defect scattered light is distributed relatively evenly over normal and non-normal collection channels; for the pit-type defects distributed on the wafer, when light is normally incident, the defect scattered light is mainly distributed in the normal collection channel, and the defect scattered light collected by the non-normal collection channel is relatively weak. Similarly, for particle defects distributed on the wafer, when light is incident obliquely, defect scattered light is mainly distributed in a non-normal collection channel; for pit defects distributed on the wafer, when light is incident obliquely, the scattered light of the defects collected by the non-normal collection channel is weak. It will be appreciated that for oblique incidence, as the angle of incidence of the light changes, the corresponding scattered light distribution will also change.

From the above, the oblique incidence detection sensitivity is higher for the convex defects; for pit-like defects, normal incidence has higher detection sensitivity. Therefore, based on the detection mode and the corresponding signal distribution, defect type analysis can be performed. The invention realizes the independent detection of normal incidence and oblique incidence by a time-sharing incidence mode, thereby saving the detection time.

The object to be measured is taken as a wafer for explanation, and it can be understood that the object to be measured can also be a chip, a glass substrate, and the like.

FIG. 1 is a block diagram of an inspection system according to an embodiment of the present invention.

The detection system includes a light source assembly 101, a detection assembly 102, a signal collection assembly 103, and a processor assembly 104.

In particular, the light source assembly 101 is configured to provide a detection beam, such as by one or more lasers.

The detection component 102 is configured to generate a detection spot corresponding to a specified incident angle based on the received detection beam. For example, the detection assembly 102 may include at least two optical branches, one of which generates a detection spot based on the detection beam from the light source assembly 101 when the optical branch is designated to be in an operating state by the processor assembly 104. The angle of incidence corresponding to the detection spot is therefore determined by the optical branch that generates the detection spot. It is to be understood that although the detection assembly 102 is described herein as including at least two optical branches to achieve the setting of the detection spot incident angle, in other embodiments, the detection assembly 102 can achieve the setting of the detection spot incident angle in other manners, such as by setting the position of the detection assembly 102 itself, or setting the state of the optical branches, etc., which need not be listed here.

In one embodiment, the at least two optical branches may correspond to at least two different incident angles, respectively, so that the wafer can be detected at different incident angles by selecting different optical branches. It will be appreciated that when the wafer is under inspection (i.e., the inspection spot is illuminated onto the wafer), the wafer will generate (e.g., by scattering or reflection) a corresponding signal light under the influence of the inspection spot. When the detection spot is irradiated to the defect, the generated signal light will vary depending on the type of defect or other parameters.

The detection assembly 102 further includes a machine for carrying the wafer, and the machine moves under the control of the processor assembly 104, so that the wafer can be moved according to the designated track, and the relative position between the wafer and the detection light spot is adjusted to realize scanning detection.

The signal collection component 103 is used to collect the signal light linearly and generate detection information associated with the incident angle. In particular, since each optical branch has an incident angle different from the other optical branches, each optical branch may generate signal light associated with the incident angle. Obviously, each set of detection information is associated with a respective angle of incidence.

The processor element 104 obtains detection information from the signal collection element 103, such as at least two groups. The processor assembly 104 then determines defect characterization information on the wafer, such as the type, location, and other parameters of the defect, based on the at least two sets of inspection information. In one embodiment, one of the at least two sets of detection information corresponds to a 0 ° angle of incidence (i.e., normal incidence). Therefore, the convex defects and the concave defects on the wafer can be accurately detected.

In the following, the detection assembly is described as comprising two optical branches, wherein the incident angle of the first optical branch is substantially 0 ° and the incident angle of the second optical branch is substantially 60 ° (i.e. oblique incidence). It is understood that the range of the incident angles is merely an example, and the user can adjust the incident angles corresponding to the first and second optical branches according to the defect feature on the wafer.

Fig. 2 is an optical architecture diagram of a detection system according to an embodiment of the present invention, in fig. 2, the detection system can implement normal incidence and oblique incidence detection modes.

The laser 201 generates a detection beam that the detection assembly 202 receives to generate a detection spot corresponding to a specified angle of incidence. In particular, a processor component (not shown) determines which optical branch can receive the detection beam through the switch 2021. Thus, the switch 2021 may provide the detection beam to the designated optical branch under control of the processor assembly. It will be appreciated that the switch 2021 may be a mirror or other component capable of switching the detection beam.

When the wafer is detected by normal incidence, the switch 2021 provides the detection beam to the first optical branch, i.e. to the shaping mirror set 2023 via the wave plate 2022, and then to the wafer surface via the

mirrors

2024, 2025, and forms the detection spot. It is understood that the shape and length of the detection light spot are controlled by the shaping mirror group 2023. For example, the shaping mirror group 2023 can also adjust the detection light spot to a point light spot or a round light spot.

When the wafer is detected by oblique incidence, the switch 2021 provides the detection beam to the second optical branch, i.e. to the mirror 2026, then to the shaping mirror set 2028 via the wave plate 2027, and then to the wafer surface via the mirror 2029, and forms a detection spot. It will be appreciated that the detection spot formed at oblique incidence is the same position and length as the detection spot formed at normal incidence. In this way, the detection spots formed with the two incidence modes can share the signal collection channel.

The

wave plates

2022, 2027 may be quarter or half wave plates, which may be used to change the polarization state of the detection beam. For example, different polarization states can be achieved for different detection beams according to requirements, such as: p-light, s-light, circularly polarized light, and the like.

Based on the above-mentioned structure, the wafer can be detected by using two different incident angles at different times. It is understood that the light source module may include a plurality of lasers, i.e. each optical branch may not share a laser, i.e. two lasers each provide a detection beam for normal incidence and oblique incidence, so that the switch 2021 may be omitted, and the processor module controls the corresponding laser.

Based on the architecture of the detection system in fig. 2, the present invention provides two detection methods, which are described with reference to fig. 3a, fig. 3b and fig. 4, wherein fig. 3a and fig. 3b are flow charts of a first detection method and a second detection method according to an embodiment of the present invention, respectively, and fig. 4 is a schematic diagram of a detection path according to an embodiment of the present invention. In this embodiment, the wafer is detected by using a linear light spot. For the sake of understanding, fig. 4 illustrates a dotted line as a concentric circle, and it is understood that the dotted line corresponds to the center of the detection area of the detection spot, and the scanning of one annular area can be completed by scanning one circle with the linear spot. In addition, although the following description is provided with respect to inspecting an entire wafer (i.e., the region to be inspected is circular), it will be understood by those skilled in the art that the region to be inspected may have other shapes.

The detection method 1: and finishing wafer detection by the first detection path based on the first incidence angle, and finishing wafer detection by the second detection path based on the second incidence angle.

In the initial detection state, the detection light spot is located at the outermost position of the wafer (as shown in the light spot position in fig. 4) by the movement of the machine. It can be understood that the present embodiment is to inspect the entire wafer, and if the region to be inspected is a portion of the wafer, the inspection spot needs to be moved to the outermost side of the region to be inspected. It will be appreciated that the detection spot comprises a detection zone, which in this embodiment is linear.

Step S301 a: the wafer is inspected according to the 1 st to nth concentric circles based on the first incident angle.

Here, the 1 st to nth concentric circles are a plurality of concentric circles arranged in the first radial direction (toward the center of the wafer), in other words, the 1 st concentric circle may correspond to the outermost side of the wafer, and the nth concentric circle may correspond to the innermost side of the wafer.

In this step, the wafer is inspected at a first incident angle. The machine rotates the wafer and performs normal collection and non-normal collection on the signal light scattered from the wafer by a signal collection component (not shown in fig. 2). After one rotation is completed along the 1 st concentric circle, the machine drives the wafer to move, so that the detection light spot moves in the first radial direction by a distance d (i.e., the distance between the centers of the adjacent concentric circles) to perform the next scanning. And repeating the steps until the detection along the Nth concentric circle is finished (at the moment, the light spot irradiates to the center of the wafer), thereby finishing the scanning of the wafer and acquiring a first group of detection information corresponding to the first incident angle. In one embodiment, the moving distance d is greater than or equal to 60% of the length of the detection spot and less than or equal to the length of the detection spot. In particular, d is less than or equal to the length of the detection zone. Thus, in the present embodiment, d is equal to the length of the detection region. d being equal to the length of the detection zone may improve the efficiency of the scanning and simplify the signal processing.

Step S302 a: and detecting the wafer according to the N-th to 1-th concentric circles under the second incident angle.

In this step, the wafer is inspected at the second incident angle. Similarly, the machine station drives the wafer to rotate, and the signal light scattered out of the wafer is subjected to normal collection and non-normal collection simultaneously through the signal collection assembly. After the Nth concentric circle rotates for one circle, the machine station drives the wafer to move, so that the detection light spot moves in the second radial direction (away from the circle center of the wafer) for the next circle of scanning, and so on until the detection corresponding to the 1 st concentric circle is finished (at the moment, the detection light spot irradiates to the outermost side position of the wafer), thereby finishing the whole scanning and acquiring the second group of detection information corresponding to the second incident angle.

The detection method 2 comprises the following steps: each concentric circle is scanned twice at the first and second incident angles, and then the next concentric circle is scanned.

Similarly, in the initial inspection state, the tool drives the wafer to move the inspection spot (or probe region) to the outermost position of the wafer (as shown in the spot position in fig. 4). Take the detection from the outer circle to the inner circle of the wafer as an example.

Step S301 b: the wafer is inspected with the 1 st concentric circle based on the first incident angle.

In this step, the wafer is inspected at a first incident angle. The machine platform drives the wafer, so that the detection light spot rotates on the wafer along the 1 st concentric circle, and the signal light scattered out of the wafer is subjected to normal collection and non-normal collection simultaneously through the signal collection assembly.

Step S302 b: based on the second incident angle, the wafer is detected according to the 1 st concentric circle.

In this step, the wafer is detected at the second incident angle, the machine drives the wafer to rotate the detection light spot on the wafer along the 1 st concentric circle, and the signal light scattered from the wafer is collected normally and collected non-normally by the signal collection component.

Step S303 b: the wafer is inspected along the 2 nd concentric circle based on the second angle of incidence.

The machine drives the wafer to move, so that the detection light spot moves a distance d in a first radial direction (towards the center of the wafer) to perform a next scanning. At this time, the wafer is inspected at the second incident angle, and the machine drives the wafer to make the inspection light spot rotate on the wafer along the 2 nd concentric circle.

Step S304 b: detecting the wafer according to the 2 nd concentric circle based on the first incident angle

In this step, the wafer is inspected at the first incident angle, and the machine drives the wafer to rotate the inspection spot on the wafer along the 2 nd concentric circle.

And so on, until the detection of two incident angles is completed for the nth concentric circle, thereby realizing the detection of the whole wafer (step S305 b).

As can be seen from the above, in the detection method 2, each of the first detection path corresponding to the first incident angle and the second detection path corresponding to the second incident angle includes a plurality of concentric circles arranged along the first radial direction, and the wafer is detected from the current concentric circle by using the first incident angle and the second incident angle in sequence in units of the concentric circles. In one embodiment, different angles of incidence correspond to the same direction of rotation, which simplifies control and reduces the complexity of processing the data obtained twice.

Therefore, two sets of inspection information corresponding to two incident modes can be obtained by the inspection method 1 or 2, and the processor assembly can determine the defect type and defect distribution on the wafer according to the two sets of inspection information.

Although the above embodiments perform the detection from the outer circle to the inner circle of the wafer, it can be understood that in another embodiment, the scanning from the inner circle to the outer circle may be adopted, and in this case, the first radial direction is a direction away from the center of the circle. In addition, as can be understood by those skilled in the art, the detection path may also be a spiral line, a Z-shape, an S-shape, a rectangle, etc., which will not be described herein.

As mentioned above, when the detection light spot is projected onto the surface of the wafer, the wafer will generate a corresponding signal light under the action of the detection light spot. The distribution of the signal light is different corresponding to different defects. For convex defects, the oblique incidence detection sensitivity is higher; for pit-like defects, normal incidence has higher detection sensitivity.

Therefore, the signal light is collected in multiple channels, and the defects on the wafer can be determined accurately. The invention provides a structure of a signal collection assembly aiming at multi-channel collection of signal light. As described above, in the present invention, since the detection spots formed by the normal incidence system and the oblique incidence system overlap, the signal collection channels can be shared.

FIG. 5a is a schematic diagram of a signal collection assembly according to an embodiment of the present invention.

The signal collection assembly 500 includes detection branches 501-503 corresponding to a plurality of collection channels. Specifically, the detection branch 501 is a normal collection channel corresponding to the detection light spot, the detection branch 502 is a first non-normal collection channel corresponding to the detection light spot, and the detection branch 503 is a second non-normal collection channel corresponding to the detection light spot.

In order to collect as much signal light as possible, each detection branch is further provided with a detection lens group (not shown) to image-wise project the collected signal light to a designated position of the line detector. For example, for the non-normal collection channel, each detection branch includes a line detector for collecting the non-normal scattered light generated by the wafer under the action of the detection spot. In this way, by the detection lens group and the line detector, a portion of the light spot irradiation area where the light intensity is relatively strong, that is, a linear detection area can be obtained.

As shown in the figure, the detection light beam irradiates the surface of the wafer to form a detection light spot, and when a defect exists at the position A, scattered light generated by the defect under the action of the detection light spot is transmitted to all directions above the wafer. In the present embodiment, a plurality of collecting channels are provided in the normal direction, non-normal direction, and each collecting channel collects scattered light spatially distributed at a nearby angle centered on one scattering angle.

As shown in fig. 5b, the defect at position a emits scattered light in a specific angle range to be projected to a specified position of the detector TCa via the detection lens group 51; similarly, when a defect exists at the position B, scattered light generated by the defect under the action of the detection spot B is projected to a specified position of the detector TCb via the detection lens group 52. Scattered light from a defect at position a will be projected to a position beside detector TCb via detection lens group 52, and similarly scattered light from a defect at position B will be projected to a position beside detector TCa via detection lens group 51. Therefore, the detectors TCa and TCb collect separately the scattered light generated by the A, B position defect without interference.

With the above configuration, the signal collecting assembly 500 can collect the scattered light of the detection spot at multiple angles, thereby generating detection information corresponding to the signal light. After the signal collection assembly 500 sends the inspection information to the processor assembly, the processor assembly is able to determine the type and distribution of defects on the wafer.

It is to be understood that although only 3 detection arms are shown in fig. 5, in other embodiments, other numbers of detection arms may be provided according to the defect characteristics of the wafer, wherein each detection arm corresponds to a different incident angle than the other detection arms.

The invention also provides a detection method, which comprises the following steps: generating a first detection light beam with a first incident angle so as to form a first detection light spot on the surface of the object to be detected, wherein the first detection light spot comprises a first detection area; scanning a region to be detected of a detected object through a first detection light beam, detecting the region to be detected, and further acquiring first detection information generated after the first detection light beam is acted by the detected object; and generating a second detection light beam with a second incidence angle, wherein the second detection light beam forms a second detection light spot on the surface of the area to be detected of the object to be detected, the second detection light spot comprises a second detection area, and the center of the second detection area is the same as the center of the first detection area. After the first scanning is finished, taking the end point of the first scanning as a starting point, and carrying out second scanning on the area to be detected of the detected object through a second detection light beam to obtain second detection information; and acquiring the defect characteristic information of the detected object according to the first detection information and the second detection information. It will be appreciated that the second scan may also include a return along the path of the first scan.

In one embodiment, the first detection spot and the second detection spot are the same size. The first detection light spot and the second detection light spot are line light spots and extend along the radius direction of the area to be detected.

In one embodiment, the first detection region is linear, the second detection region is linear, and the center of the first detection region coincides with the center of the first detection light spot; the center of the second detection area is superposed with the center of the second detection light spot; the length of the first detection area is smaller than that of the first detection light spot, and the length of the second detection area is smaller than that of the second detection light spot.

In one embodiment, when the first detection light spot and the second detection light spot are line light spots, an included angle between an extending direction of the first detection light spot and a direction of the first scanning in the first detection process is greater than zero, and an included angle between an extending direction of the second detection light spot and a direction of the second scanning in the second detection process is greater than zero. It will be appreciated that the detection range is at a maximum when the detection spot is perpendicular to the direction of scanning.

When the region to be measured is circular, the object to be measured can be scanned by using concentric circles, spiral lines or other scanning paths.

Specifically, when the scanning tracks are concentric circles, the object to be detected can be detected by setting the scanning paths of the first scanning and the second scanning.

(1) The scanning is performed twice per concentric circle according to the arrangement order of the concentric circles.

The step of the first scanning includes: the object to be measured winds the circle center of the area to be measured and carries out first rotation on an axis which is perpendicular to the surface of the area to be measured. The step of the second scanning includes: and enabling the object to be measured to bypass the circle center of the area to be measured and perform second rotation on the axis which is perpendicular to the area to be measured. Thus, different angles of scanning can be performed on the same concentric circle. In one embodiment, the first rotation and the second rotation are in the same direction, thereby simplifying control and reducing the complexity of processing data obtained twice.

After the second rotation is finished, the position of the measured object relative to the first detection light spot is translated by a specific step length along the diameter direction of the area to be measured (to reach another concentric circle). And then, repeating the steps of the first scanning, the second scanning and/or the translation until the region to be detected is detected by the first detection light spot and the second detection light spot. In one embodiment, the first detection zone and the second detection zone are equal in length and equal to the certain step size in the direction along the translation.

(2) And after the area to be detected is scanned by using the first detection beam, scanning the area to be detected by using the second detection beam in an opposite path.

The step of the first scanning includes: enabling the object to be detected to bypass the circle center of the area to be detected and perform first rotation on an axis which is perpendicular to the area to be detected, and performing first detection; after the first rotation, the measured object is subjected to first translation along a first diameter direction of the area to be measured; and repeating the steps of the first rotation and the first detection and/or the first translation until the detected area is detected by the first detection light spot. The step of the second scanning includes: enabling the object to be detected to bypass the circle center of the area to be detected and perform second rotation on the axis which is perpendicular to the area to be detected, and performing second detection; after the second rotation, the measured object is subjected to second translation along the diameter direction of the area to be measured, wherein the direction of the second translation is opposite to the direction of the first translation; repeating the steps of the first rotation and the first detection and/or the first translation until the detected region is detected. In one embodiment, the first rotation is in the same direction as the second rotation.

In one embodiment, the first probe region and the second probe region have the same dimension along the radius of the region under test, and the step size of the first translation is equal to the step size of the second translation. In an embodiment, in the direction along the first translation, the size of the first detection zone is equal to the step size of the first translation and the size of the second detection zone is equal to the step size of the second translation.

As mentioned above, the region to be measured of the object to be measured may also be circular, and the scanning trajectory may be a spiral.

Specifically, the step of the first scanning includes: enabling the object to be measured to bypass the circle center of the area to be measured and perform third rotation on the axis which is perpendicular to the area to be measured; and in the first rotation process, the detection light spot is enabled to perform third translation relative to the first detection light spot along the diameter direction of the area to be detected. The step of the second scanning includes: making the object to be measured wind the circle center of the area to be measured and rotate in a fourth way along the axis vertical to the area to be measured; and in the second rotation process, the detection light spot is enabled to perform fourth translation relative to the second detection light spot along the diameter direction of the area to be detected. In one embodiment, the direction of the third rotation is opposite to the direction of the fourth rotation, so that the areas of the two sketches are the same, enabling an accurate analysis of the scanned area.

Compared with the traditional detection method (i.e. the detection is finished and the detection is carried out again at the starting point), the detection method saves the moving time of the wafer, and reduces the positioning error due to the fact that the wafer is prevented from moving to the starting point again, so that the algorithm of matching and aligning the detection results of two times is much simpler, and the detection speed can be obviously increased.

In addition, because different particles have different dispersion action strengths, the technical scheme of the invention can realize multi-angle detection based on the same light source. In other words, light sources of the same wavelength may be used to detect different particles.

Although the above-described embodiment uses line spots for detection, the detection method of the present invention is also applicable to a spot or area spot detection method. It will be appreciated that when using a spot/area spot to inspect a wafer, the shaping mirror set needs to be adjusted to form the spot/area spot. For example, the wafer may be inspected by using the spot light in a spiral manner, that is, the wafer is inspected by using the spiral, and after the inspection is completed, the inspection is performed in the reverse direction at the end of the spiral. As will be understood by those skilled in the art, a spiral refers to a scanning trajectory.

Thus, while the present invention has been described with reference to specific examples, which are intended to be illustrative only and not to be limiting of the invention, it will be apparent to those of ordinary skill in the art that changes, additions or deletions may be made to the disclosed embodiments without departing from the spirit and scope of the invention.

Claims

1. A detection system, comprising:

a detection component configured to generate a detection spot corresponding to a specified angle of incidence based on the received detection beam;

the signal collection component is configured to collect signal light generated by the object to be detected under the action of the detection light spot, and further generate detection information corresponding to the incidence angle; and

a processor component configured to cause the detection component to generate the detection light spot sequentially at a first incident angle and a second incident angle, and determine defect characteristic information on the object to be detected based on at least first and second detection information corresponding to the first and second incident angles, wherein,

the processor component is further configured to cause the detection component to:

detecting the object to be detected by a first detection path based on the first incidence angle; and

and detecting the object to be detected by a second detection path corresponding to the first detection path based on the second incidence angle.

2. The detection system of claim 1,

the first detection path includes a plurality of concentric circles arranged in a first radial direction, and the second detection path includes a plurality of concentric circles arranged in a second radial direction opposite to the first radial direction; or

The first detection path and the second detection path each include a plurality of concentric circles arranged in a first radial direction, wherein when detection is performed according to the same concentric circle, switching between detection spots corresponding to different incident angles is performed on the same concentric circle.

3. A detection system according to claim 2, wherein the concentric circles are scanning tracks at the center of the detection zones corresponding to the detection spots, wherein the detection zones extend in the radial direction of the concentric circles.

4. A detection system according to claim 3 wherein the difference between the adjacent concentric circular radii is equal to or less than the length of the detection zone.

5. The detection system of claim 1, wherein the detection component comprises:

a first optical branch configured to generate the detection spot at the first incident angle based on the received detection beam;

a second optical branch configured to generate the detection spot at the second incident angle based on the received detection beam, wherein the second incident angle is different from the first incident angle; a switch configured to provide the detection beam to the first optical branch or the second optical branch.

6. A method of detection, comprising:

generating a first detection light beam, wherein the first detection light beam has a first incident angle, the first detection light beam forms a first detection light spot on the surface of the object to be detected, and the first detection light spot comprises a first detection area;

performing first scanning on a region to be detected of the object to be detected through the first detection light beam, performing first detection on the region to be detected, and acquiring first detection information generated after the first detection light beam is acted on the object to be detected;

generating a second detection light beam, wherein the second detection light beam has a second incident angle, the second incident angle is different from the first incident angle, the second detection light beam forms a second detection light spot on the surface of the region to be detected of the object to be detected, the second detection light spot comprises a second detection region, and the center of the second detection region is the same as the center of the first detection region;

after the first scanning, taking the end point of the first scanning as a starting point, performing second scanning on the region to be detected of the detected object through the second detection light beam, performing second detection on the region to be detected, and acquiring second detection information;

and acquiring the defect characteristic information of the detected object according to the first detection information and the second detection information.

7. The detection method according to claim 6, wherein the region to be detected of the object to be detected is circular;

the step of the first scanning comprises: enabling the object to be measured to bypass the circle center of the area to be measured and perform first rotation on an axis which is perpendicular to the surface of the area to be measured;

the step of the second scanning comprises: and enabling the object to be measured to bypass the circle center of the area to be measured and perform second rotation on the axis which is perpendicular to the area to be measured.

8. The detection method of claim 7, further comprising: after the second rotation, enabling the position of the measured object relative to the first light spot to translate for a specific step length along the diameter direction of the area to be measured;

and repeating the first scanning, the second scanning and/or the translating step until the area to be detected is detected by the first detection light spot and the second detection light spot.

9. The detection method according to claim 8, wherein the first detection zone and the second detection zone are equal in length and equal to the certain step size in the direction of the translation.

10. The detection method of claim 7, wherein the step of first scanning comprises: enabling the object to be detected to bypass the circle center of the area to be detected and perform first rotation on an axis which is perpendicular to the area to be detected, and performing the first detection; after the first rotation, the measured object is subjected to first translation along a first diameter direction of the area to be measured; repeating the steps of the first rotation and the first detection and/or the first translation until the detected area is detected by the first detection light spot;

the step of the second scanning comprises: enabling the object to be detected to bypass the circle center of the area to be detected and perform second rotation on the axis which is perpendicular to the area to be detected, and performing second detection; after the second rotation, the measured object is subjected to second translation along the diameter direction of the area to be measured, wherein the direction of the second translation is opposite to the direction of the first translation; and repeating the steps of the second rotation and the second detection and/or the second translation until the detected area is detected by the second detection light spot.

11. The detection method according to claim 7 or 10, wherein the first rotation and the second rotation are in the same direction.

12. The detection method according to claim 10, wherein the first detection region and the second detection region have the same size in the radial direction of the region to be detected, and the step size of the first translation is equal to the step size of the second translation.

13. The detection method according to claim 7 or 12, wherein in the direction of the first translation, the size of the first detection zone is equal to the step size of the first translation and the size of the second detection zone is equal to the step size of the second translation.

14. The detection method according to claim 6, wherein the region to be detected of the object to be detected is circular;

the step of the first scanning comprises: enabling the object to be measured to bypass the circle center of the area to be measured and perform third rotation on the axis which is perpendicular to the area to be measured; in the first rotation process, the detection light spot is enabled to perform third translation relative to the first detection light spot along the diameter direction of the area to be detected;

the step of the second scanning comprises: making the object to be measured wind the circle center of the area to be measured and rotate in a fourth way along the axis vertical to the area to be measured; and in the second rotation process, the detection light spot is enabled to perform fourth translation relative to the second detection light spot along the diameter direction of the area to be detected.

15. The detection method of claim 14, wherein a direction of the third rotation is opposite to a direction of the fourth rotation.

16. The detection method of claim 6, wherein the step of second scanning comprises:

returning along the path of the first scan;

the first detection spot and the second detection spot are the same size in a direction perpendicular to the first scanning direction.

17. The detection method according to claim 6, wherein the first detection light spot and the second detection light spot are linear, and the extension direction of the first detection light spot is along the radius direction of the region to be detected; the extending direction of the second detection light spot is along the radius direction of the region to be detected.

18. The detection method according to any one of claims 6 to 8, wherein the first detection spot and the second detection spot are line spots.

19. The detection method according to claim 6, wherein the first detection region is linear, the second detection region is linear, and the center of the first detection region coincides with the center of the first detection spot; the center of the second detection area is superposed with the center of the second detection light spot; the first detection region length is smaller than the first detection light spot length, and the second detection region length is smaller than the second detection light spot length.

20. The detection method according to claim 19, wherein when the first detection spot and the second detection spot are line spots, an angle between an extending direction of the first detection spot and a direction of the first scanning in the first detection process is greater than zero, and an angle between an extending direction of the second detection spot and a direction of the second scanning in the second detection process is greater than zero.