Measurement method and measurement apparatus for substrate to be tested

Abstract

A measurement apparatus for a substrate (19) to be tested, and a measurement method for said substrate (19). The surface of said substrate (19) has a first point (101) to be tested and a second point (102) to be tested. The measurement apparatus for a substrate (19) to be tested comprises: a transmitting unit (11), which transmits a feature pattern to a substrate (19) to be tested, so as to execute displacement measurement processing on said substrate (19); a collection unit (12), which acquires an image of the feature pattern formed by the transmitting unit (11); and a processing unit (13), which acquires a first target distance between a first point (101) to be tested and a second point (102) to be tested in a first measurement direction. By means of transmitting to the surface of a substrate (19) to be tested a feature pattern having a first feature point and a second feature point, which can be recognized in a first measurement direction, the distance between points to be tested is deduced by means of a change in the morphology of the pattern, such that relative position information of different points to be tested can be acquired.

Description

Detection method and detection device for substrate to be tested Technical Field

[0001] The present invention relates to the field of substrate detection, and in particular to a detection method and a detection device for a substrate to be detected. Background Art

[0002] Substrate surface pattern detection is a method of obtaining substrate pattern information by observing patterns on the substrate surface. During the observation process, in addition to obtaining information about the number of patterns, the user also needs to obtain information about the relative positions of different patterns. However, in the prior art, due to the large distance between the patterns, they cannot be displayed within the field of view of the same microscope. Therefore, the position information between different patterns can only be determined by the displacement of the microscope lens. However, the displacement of the microscope lens is achieved by mechanical devices such as stepping motors, which has very low accuracy and cannot meet measurement requirements. Therefore, how to accurately obtain the relative position information between different patterns during substrate surface pattern detection is a problem that the prior art needs to solve. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method and a device for detecting a substrate to be tested, which can accurately obtain relative position information between different patterns.

[0004] In order to solve the above problems, the present invention provides a detection device for a substrate to be tested, wherein the surface of the substrate to be tested has a first point to be tested and a second point to be tested, and the device includes: a transmitting unit, wherein the transmitting unit transmits a characteristic pattern to the substrate to be tested and performs displacement measurement processing on the substrate to be tested, wherein the displacement measurement processing includes: forming a characteristic pattern at the first point to be tested and the second point to be tested on the surface of the substrate to be tested, wherein the characteristic pattern includes a first characteristic point and a second characteristic point identifiable in a first measurement direction, and the distance between the first characteristic point and the second characteristic point along the first measurement direction is a first characteristic distance; and an acquisition unit, wherein the acquisition unit acquires an image of the characteristic pattern formed by the transmitting unit at the first point to be tested, and obtains a first positioning image; obtain an image of the characteristic pattern of the transmitting unit at the second point to be measured to obtain a second positioning image; and a processing unit, wherein the processing unit obtains a first displacement between the first point to be measured and the first feature point along the first measuring direction according to the first positioning image obtained by the acquisition unit, and the direction in which the second feature point points to the first feature point is the positive direction of the first displacement; obtains a second displacement between the second point to be measured and the second feature point along the first measuring direction according to the second positioning image, and the direction in which the first feature point points to the second feature point is the positive direction of the second displacement; and obtains a first target distance between the first point to be measured and the second point to be measured along the first measuring direction according to the first displacement, the second displacement and the first characteristic distance.

[0005] To solve the above problems, the present invention provides a method for inspecting a substrate to be inspected, wherein the surface of the substrate to be inspected has a first point to be inspected and a second point to be inspected, and the method comprises: performing displacement measurement processing on the substrate to be inspected using a characteristic pattern, the displacement measurement processing comprising: forming a characteristic pattern at the first point to be inspected and the second point to be inspected on the surface of the substrate to be inspected, the characteristic pattern comprising a first characteristic point and a second characteristic point identifiable in a first measurement direction, and a distance between the first characteristic point and the second characteristic point along the first measurement direction being a first characteristic distance; acquiring an image of the characteristic pattern of the first point to be inspected to obtain a first positioning image; acquiring an image of the characteristic pattern of the second point to be inspected to obtain a second positioning image; acquiring a first displacement between the first point to be inspected and the first characteristic point along the first measurement direction based on the first positioning image, wherein a direction in which the second characteristic point points toward the first characteristic point is a positive direction of the first displacement; acquiring a second displacement between the second point to be inspected and the second characteristic point along the first measurement direction based on the second positioning image, wherein a direction in which the first characteristic point points toward the second characteristic point is a positive direction of the second displacement; and acquiring a first target distance between the first point to be inspected and the second point to be inspected along the first measurement direction based on the first displacement, the second displacement, and the first characteristic distance.

[0006] The present invention projects a feature pattern having identifiable first and second feature points in a first measurement direction onto the surface of a substrate to be measured, and infers the distance between the test points through changes in the pattern morphology, thereby accurately obtaining the relative position information between different test points. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG1A is a schematic structural diagram of a specific embodiment of the detection device for a substrate to be tested according to the present invention.

[0008] FIG1B is a schematic structural diagram of a specific embodiment of the detection device for a substrate to be tested according to the present invention.

[0009] FIG2A is a schematic structural diagram of a specific embodiment of the detection device for a substrate to be tested according to the present invention.

[0010] FIG2B is a schematic structural diagram of a specific embodiment of the detection device for a substrate to be tested according to the present invention.

[0011] FIG3A is a schematic structural diagram of a specific embodiment of the detection device for a substrate to be tested according to the present invention.

[0012] FIG3B is a schematic structural diagram of a specific embodiment of the detection device for a substrate to be tested according to the present invention.

[0013] FIG4 is a schematic diagram showing the implementation steps of a specific embodiment of the method for detecting a substrate to be tested according to the present invention. DETAILED DESCRIPTION

[0014] The specific embodiments of the detection device for a substrate to be tested and the detection method for a substrate to be tested provided by the present invention are described in detail below with reference to the accompanying drawings.

[0015] 1A, 1B, 2A and 2B are schematic structural diagrams of a specific embodiment of the detection device for a substrate to be tested according to the present invention, comprising: an emitting unit 11, a collection unit 12, and a processing unit 13, for detecting a first test point 101 and a second test point 102 on the surface of a substrate to be tested 19.

[0016] The transmitting unit 11 forms a characteristic pattern at the first and second test points 101 and 102 on the surface of the substrate 19 to be tested. The characteristic pattern includes a first characteristic point and a second characteristic point identifiable in the first measuring direction. The distance between the first and second characteristic points along the first measuring direction is a first characteristic distance.

[0017] In this embodiment, the transmitting unit 11 forms at least two characteristic patterns at the first and second test points 101 and 102 on the surface of the substrate 19 to be tested. Specifically, the transmitting unit is a structured light emitter. In other embodiments, the transmitting unit 11 may form only one characteristic pattern at the first and second test points on the surface of the substrate 19 to be tested.

[0018] In this embodiment, the characteristic pattern is a stripe pattern, which includes multiple parallel stripes arranged periodically. In other embodiments, the characteristic pattern can also be an arc, a dot, or any other measurable pattern.

[0019] The stripe widths of the at least two characteristic patterns are respectively a first width d1 and a second width d2, and the at least two characteristic patterns are generated by light beams of a first wavelength and a second wavelength, respectively. In other specific embodiments, the stripe patterns of the first width d1 and the second width d2 can also be generated by light sources of the same wavelength in a time-sharing manner, irradiated onto the surface of the substrate to be measured 19 at a first frequency and a second frequency, respectively, and filtered and collected during a subsequent acquisition process. The emitting unit can be any light source capable of generating a pattern. The first characteristic point and the second characteristic point are stripes adjacent to the first point to be measured 101 and the second point to be measured 102.

[0020] Specifically, the emitting unit 11 includes a light source and a pattern element, wherein the light source emits a light beam to the pattern element to project the pattern of the pattern element onto the substrate to be measured. Alternatively, the emitting unit 11 includes a display screen.

[0021] The pattern element is an optical component with adjustable pattern, such as DMD, SLM, to adjust the spacing between stripes. Alternatively, the pattern element is a grating with a fixed pattern, and at least two characteristic patterns are formed by replacing the grating.

[0022] The acquisition unit 12 obtains a first positioning image and a second positioning image of the positions of the first point to be measured 101 and the second point to be measured 102 on the surface of the substrate to be measured 19. In this specific embodiment, the first point to be measured 101 and the second point to be measured 102 on the surface of the substrate to be measured and the characteristic patterns of the adjacent positions are respectively acquired under the stripe patterns of the first width d1 and the second width d2 to form the first positioning image and the second positioning image. In this specific embodiment, the target pattern to be measured is a defect on the surface of the substrate to be measured 19. In other specific embodiments, the above-mentioned target pattern can also be any pattern on the surface of the substrate that needs to be accurately measured. In this specific embodiment, the emitting unit 11 and the acquisition unit 12 are on the same side of the substrate to be measured 19, and what is acquired is the reflected or scattered light of the substrate to be measured 19. In other specific embodiments, the emitting unit 11 and the acquisition unit 12 are on different sides of the target pattern of the substrate to be measured 19. In this case, what is acquired is the transmission pattern generated by the emitting unit 11 irradiating the substrate to be measured 19.

[0023] Figures 1A and 1B illustrate the acquisition of light from a first test point 101, with Figure 1A showing structured light of a first width d1 and Figure 1B showing structured light of a second width d2. Figures 2A and 2B illustrate the acquisition of light from a second test point 102, with Figure 2A showing structured light of a first width d1 and Figure 2B showing structured light of a second width d2. The emission unit 11 can project light in a time-sharing manner or simultaneously; the corresponding acquisition unit 12 can acquire light in a time-sharing manner or simultaneously using filtering. In this specific embodiment, the first width d1 is smaller than the second width d2.

[0024] After obtaining the pattern, the processing unit 13 is connected to the transmitting unit 11 and the acquisition unit 12 to obtain the characteristic pattern information generated by the transmitting unit 11, as well as the first positioning image and the second positioning image acquired by the acquisition unit 12, and obtains the first displacement between the first point to be measured 101 and the first feature point along the first measurement direction according to the first positioning image, obtains the second displacement between the second point to be measured 102 and the second feature point along the first measurement direction according to the second positioning image, and then obtains the first target distance between the first point to be measured 101 and the second point to be measured 102 along the first measurement direction according to the first displacement, the second displacement and the first characteristic distance.

[0025] In this specific embodiment, the positional relationship between the first test point 101 and the second test point 102 is obtained. The processing unit 13 obtains the positional relationship based on the structured light information emitted by the transmitting unit 11 and the structured light pattern captured by the collecting unit 12. Within the same field of view, the width of the structured light is varied. Optical components with spatial resolution, such as DMDs and SLMs, can be used to modulate the spacing of the projected light. By quantifying the relationship between the change in the width of the projected image and the change in the width of the structured light itself, the distance between the two structured light fringes, i.e., the first characteristic distance, can be obtained.

[0026] In the same field of view, the relationship between the first measured point 101 and the second measured point 102 and the adjacent structured light fringes is obtained, that is, the first characteristic distance between the first measured point 101 and the first characteristic point along the first measurement direction, and the second characteristic distance between the second measured point 102 and the second characteristic point along the first measurement direction, so that the first target distance between the first measured point 101 and the second measured point 102 along the first measurement direction can be obtained.

[0027] The first characteristic distance may be a known design value, or may be obtained by the following method. Specifically, refer to Figures 1A, 1B, 2A, and 2B.

[0028] According to the distance relationship processed by multiple position measurements and the preset relationship, the first target distance is obtained, including: obtaining the first target distance L according to equation (1),

[0029] L = N*d1 + a; L = N*d2 + b (1);

[0030] Where L is the first target distance, d1 is the period of the characteristic pattern in the first displacement measurement process, d2 is the period of the characteristic pattern in the second displacement measurement process; a is the sum of the first displacement and the second displacement in the first displacement measurement process, b is the sum of the first displacement and the second displacement in the second displacement measurement process, and N is the number of fringes between the first feature point and the second feature point.

[0031] The sum of the first characteristic distances processed by multiple displacement measurements is a preset value y;

[0032] Obtaining the first target distance according to the distance relationship processed by multiple position measurements and the preset relationship includes: obtaining the first target distance L according to equation (2):

[0033] L=(y+a+b) / 2(2).

[0034] When moving from field of view A to field of view B, the acquisition unit 12 and the substrate to be measured 19 can move together, or only one of them can move. The relative movement distance value refers to the relative movement distance. The movement distance can be obtained by a grating ruler.

[0035] Obviously, the above method is applicable when the stripe widths are d1 and d2, and the relative movement distance between the test point and the stripe is within the same stripe period, that is, N is the same under the two irradiations. If the variation distance exceeds this range, the two N values ​​can also be obtained by the relative movement between the acquisition unit 12 and the substrate 19 to be tested. The specific method is to measure the relative movement distance between the acquisition unit 12 and the substrate 19 to be tested along the measurement direction to obtain a first movement distance; based on the first movement distance and the period of the characteristic pattern, the period number N of the first movement distance is obtained, where the period number N is the maximum integer less than or equal to the ratio of the first movement distance to the period of the characteristic pattern; and the first characteristic distance is obtained by multiplying the period number N by the period of the characteristic pattern.

[0036] The above method of obtaining N may also be to use a counter to measure the number of stripes passed by during the movement of the field of view, thereby obtaining accurate N.

[0037] Of course, in other specific embodiments, multiple displacement measurement processes can also be performed on the substrate to be tested using multiple characteristic patterns. That is, the width of the width stripes is changed three or more times, and the transformation method is as described above. Different wavelengths of light can be used, or the same wavelength of light can be used for time-sharing irradiation. The acquisition process improves the acquisition accuracy by taking the average value. During the test process, the first characteristic distance between the first characteristic point and the second characteristic point in the characteristic pattern in the multiple displacement measurement processes is different, and there is a preset relationship between the first characteristic distances of the multiple displacement measurement processes; based on the first displacement, the second displacement and the first characteristic distance, the first target distance between the first point to be tested and the second point to be tested along the first measurement direction is obtained, including: obtaining the target distance based on the distance relationship of the multiple position measurement processes and the preset relationship, and the distance relationship includes: the sum of the first displacement, the second displacement and the first characteristic distance is equal to the target distance. The preset relationship is: the difference or sum of the first characteristic distances of multiple displacement measurement processes is a preset value; or, if the characteristic pattern is a periodic pattern, the period of the characteristic pattern along the first measurement direction in the multiple displacement measurement processes is different; the first characteristic point is the periodic unit with the smallest distance from the first measured point, and the first characteristic point is the periodic unit with the smallest distance from the second measured point; the first characteristic distance is an integer multiple of the period; the preset relationship includes: the integer multiples of the first characteristic distances of multiple displacement measurement processes are the same.

[0038] The illumination in the above specific embodiment is a stripe pattern, so only the accurate distance between the first test point 101 and the second test point 102 in the direction perpendicular to the stripe structured light can be obtained. If it is necessary to obtain the distance between the first test point 101 and the second test point 102 on the two-dimensional surface of the substrate, it is necessary to provide a rotation unit connected to the transmitting unit 11 to rotate the emission angle of the transmitting unit, thereby rotating the angle of the structured light. For example, it can be rotated 90° to obtain the distance in two directions. Then, through angle calculation, the distance between the first test point 101 and the second test point 102 on the two-dimensional surface of the substrate 19 to be tested is obtained.

[0039] 3A and 3B are schematic structural diagrams of another specific embodiment of the detection device for the substrate to be tested according to the present invention. In another specific embodiment, the rotation unit may not be provided. Instead, as shown in FIG3A and 3B, the characteristic pattern generated by the emitting unit 11 may be configured to include a third characteristic point and a fourth characteristic point identifiable in the second measurement direction, and the distance between the third characteristic point and the fourth characteristic point along the second measurement direction is a second characteristic distance. The acquisition unit 12 further acquires an image of the characteristic pattern of the third point to be tested to obtain a third positioning image; and acquires an image of the characteristic pattern of the fourth point to be tested to obtain a fourth positioning image. The processing unit 13 further acquires a third distance between the first point to be tested and the third characteristic point along the second measurement direction based on the third positioning image; acquires a fourth distance between the second point to be tested and the fourth characteristic point along the second measurement direction based on the fourth positioning image; and acquires a second target distance between the first point to be tested and the second point to be tested along the second measurement direction based on the third distance, the fourth distance, and the second characteristic distance.

[0040] The second measurement direction can be perpendicular to the first measurement direction or configured at a preset angle. The detection of the second measurement direction can be implemented in a time-sharing or simultaneous manner. In a specific embodiment of simultaneous implementation, in order to better distinguish the characteristic patterns in the two directions, light waves of different frequencies can be projected, and different characteristic patterns can be obtained through filtering at the acquisition end. The processing unit 13 can further obtain the two-dimensional spatial distance between the first to-be-measured point and the second to-be-measured point based on the first target distance and the second target distance.

[0041] 4 is a schematic diagram of the implementation steps of a specific embodiment of the detection method for a substrate to be tested according to the present invention, comprising: step S30, performing displacement measurement processing on the substrate to be tested through a characteristic pattern, the displacement measurement processing comprising: forming a characteristic pattern at a first point to be tested and a second point to be tested on the surface of the substrate to be tested, the characteristic pattern comprising a first characteristic point and a second characteristic point identifiable in a first measurement direction, and the distance between the first characteristic point and the second characteristic point along the first measurement direction being a first characteristic distance; step S31, acquiring an image of the characteristic pattern of the first point to be tested to obtain a first positioning image, and acquiring an image of the characteristic pattern of the second point to be tested to obtain a second positioning image; step S32, acquiring a first displacement between the first point to be tested and the first characteristic point along the first measurement direction according to the first positioning image, acquiring a second displacement between the second point to be tested and the second characteristic point along the first measurement direction according to the second positioning image, and acquiring a first target distance between the first point to be tested and the second point to be tested along the first measurement direction according to the first displacement, the second displacement and the first characteristic distance.

[0042] Referring to step S30, a displacement measurement process is performed on the substrate to be measured using a characteristic pattern. The displacement measurement process includes: forming a characteristic pattern at a first point to be measured and a second point to be measured on the surface of the substrate to be measured, the characteristic pattern including a first characteristic point and a second characteristic point identifiable in a first measurement direction, and a distance between the first characteristic point and the second characteristic point along the first measurement direction is a first characteristic distance.

[0043] In this specific embodiment, the transmitting unit 11 forms at least two characteristic patterns at the first test point 101 and the second test point 102 on the surface of the substrate 19 to be tested. Specifically, the transmitting unit 11 is a structured light emitter. In other embodiments, the transmitting unit 11 may form only one characteristic pattern at the first test point 101 and the second test point 102 on the surface of the substrate 19 to be tested.

[0044] In this embodiment, the characteristic pattern is a stripe pattern, which includes multiple parallel stripes arranged periodically. In other embodiments, the characteristic pattern can also be an arc, a dot, or any other measurable pattern.

[0045] The stripe widths of the at least two characteristic patterns are respectively a first width d1 and a second width d2, and the at least two characteristic patterns are generated by light beams of a first wavelength and a second wavelength, respectively. In other specific embodiments, the stripe patterns of the first width d1 and the second width d2 can also be generated by light sources of the same wavelength in a time-sharing manner, irradiated onto the surface of the substrate to be measured 19 at a first frequency and a second frequency, respectively, and filtered and collected during a subsequent acquisition process. The emitting unit can be any light source capable of generating a pattern. The first characteristic point and the second characteristic point are stripes adjacent to the first point to be measured 101 and the second point to be measured 102.

[0046] Specifically, the emitting unit 11 includes a light source and a pattern element, wherein the light source emits a light beam to the pattern element to project the pattern of the pattern element onto the substrate to be tested. Alternatively, the emitting unit is a display screen.

[0047] The pattern element is an optical component with adjustable pattern, such as DMD, SLM, to adjust the spacing between stripes. Alternatively, the pattern element is a grating with a fixed pattern, and at least two characteristic patterns are formed by replacing the grating.

[0048] Referring to step S31 , an image of the characteristic pattern of the first point to be measured 101 is acquired to obtain a first positioning image, and an image of the characteristic pattern of the second point to be measured 102 is acquired to obtain a second positioning image.

[0049] In this embodiment, structured light patterns are captured at first and second test points 101 and 102 on the surface of a substrate 19 under illumination conditions of structured light of first and second widths d1 and d2, respectively, along with adjacent locations, to form first and second positioning images. In this embodiment, the target pattern being measured is a defect on the substrate surface. In other embodiments, the target pattern can be any pattern on the substrate surface that requires precise measurement.

[0050] Figures 1A and 1B illustrate the acquisition of light from a first test point 101, with Figure 1A showing structured light of a first width d1 and Figure 1B showing structured light of a second width d2. Figures 2A and 2B illustrate the acquisition of light from a second test point 102, with Figure 2A showing structured light of a first width d1 and Figure 2B showing structured light of a second width d2. The emission unit 11 can project light in a time-sharing manner or simultaneously; the corresponding acquisition unit 12 can acquire light in a time-sharing manner or simultaneously using filtering. In this specific embodiment, the first width d1 is smaller than the second width d2.

[0051] In this embodiment, the emitting unit 11 and the collecting unit 12 are located on the same side of the substrate 19, and the collected pattern is the reflection pattern of the substrate 19. In other embodiments, the emitting unit 11 and the collecting unit 12 are located on different sides of the substrate 19, and in this case, the collected pattern is the transmission pattern generated by the emitting unit 11 irradiating the substrate 19.

[0052] Referring to step S32, a first displacement along the first measurement direction between the first point to be measured and the first feature point is obtained according to the first positioning image, a second displacement along the first measurement direction between the second point to be measured and the second feature point is obtained according to the second positioning image, and a target distance along the first measurement direction between the first point to be measured and the second feature point is obtained according to the first displacement, the second displacement and the first feature distance.

[0053] The width of the structured light is changed. The spacing of the projected light can be modulated using optical components with spatial resolution, such as DMDs and SLMs. By quantifying the relationship between the change in the width of the projected image and the change in the width of the structured light itself, the distance information between the two structured light stripes can be obtained. By obtaining the relationship between a first test point 101 and a second test point 102 and the adjacent structured light stripes, that is, the first characteristic distance between the first test point 101 and the first feature point along the first measurement direction, and the second characteristic distance between the second test point 102 and the second feature point along the first measurement direction, the first target distance between the first test point 101 and the second test point 102 along the first measurement direction can be obtained.

[0054] The above method of obtaining N may also be to use a counter to measure the number of stripes passed by during the movement of the field of view, thereby obtaining accurate N.

[0055] Of course, in other specific embodiments, multiple displacement measurements can be performed on the substrate to be measured using multiple characteristic patterns. That is, the width of the width stripes can be varied three or more times. The variation method is the same as described above, and different wavelengths of light can be used, or the same wavelength of light can be used for time-sharing irradiation.

[0056] In other embodiments, multiple displacement measurement processes may be performed on the substrate to be measured using multiple characteristic patterns to obtain multiple first target distances; the method further includes: averaging the multiple first target distances to obtain a final first target distance.

[0057] During the test process, the first characteristic distance between the first characteristic point and the second characteristic point in the characteristic pattern in the multiple displacement measurement processes is different, and there is a preset relationship between the first characteristic distances of the multiple displacement measurement processes; according to the first displacement, the second displacement and the first characteristic distance, the target distance between the first point to be measured and the second point to be measured along the first measurement direction is obtained, including: according to the distance relationship of the multiple position measurement processes and the preset relationship, the target distance is obtained, and the distance relationship includes: the sum of the first displacement, the second displacement and the first characteristic distance is equal to the target distance. The preset relationship is: the difference or sum of the first characteristic distances of the multiple displacement measurement processes is a preset value; or, if the characteristic pattern is a periodic pattern, the period of the characteristic pattern along the first measurement direction in the multiple displacement measurement processes is different; the first characteristic point is the periodic unit with the smallest distance from the first point to be measured, and the first characteristic point is the periodic unit with the smallest distance from the second point to be measured; the first characteristic distance is an integer multiple of the period; the preset relationship includes: the integer multiples of the first characteristic distances of the multiple displacement measurement processes are the same.

[0058] Specifically, referring to Figures 1A, 1B, 2A, and 2B, the moving distance can be obtained by the grating ruler. When the field of view moves from the first position to the second position:

[0059] Obtaining the first target distance according to the distance relationship processed by multiple position measurements and the preset relationship, including: obtaining the first target distance L according to equation (1), L=N*d1+a; L=N*d2+b(1);

[0060] Where L is the first target distance, d1 is the period of the characteristic pattern in the first displacement measurement process, d2 is the period of the characteristic pattern in the second displacement measurement process; a is the sum of the first displacement and the second displacement in the first displacement measurement process, b is the sum of the first displacement and the second displacement in the second displacement measurement process, and N is the number of fringes between the first feature point and the second feature point.

[0061] The sum of the first characteristic distances processed by multiple displacement measurements is a preset value y;

[0062] Obtaining the first target distance according to the distance relationship processed by multiple position measurements and the preset relationship includes: obtaining the first target distance L according to equation (2): L=(y+a+b) / 2(2).

[0063] Obviously, the above method is applicable under the conditions of stripe widths d1 and d2, and the relative movement distance between the defect and the stripe is within the same stripe period, that is, N is the same under the two irradiations. If the variation distance exceeds this range, the two N values ​​can also be obtained by the relative movement between the acquisition unit 12 and the substrate to be tested 19. The specific method is to measure the relative movement distance between the acquisition unit 12 and the substrate to be tested 19 along the measuring direction to obtain a first movement distance; obtain the period number N of the first movement distance based on the first movement distance and the period of the characteristic pattern, where the period number N is the maximum integer less than or equal to the ratio of the first movement distance to the period of the characteristic pattern; and obtain the first characteristic distance based on the product of the period number N and the period of the characteristic pattern.

[0064] Second embodiment

[0065] The above embodiment is described by taking the example of performing multiple displacement measurement processes on the substrate to be measured using multiple characteristic patterns to obtain multiple first target distances.

[0066] In the second embodiment of the detection method of the present application, a plurality of first target distances can be obtained by performing a displacement measurement process on the substrate to be detected using only one characteristic pattern.

[0067] The second embodiment of the method for detecting a substrate to be tested of the present application is described below.

[0068] The similarities between this embodiment and the previous embodiment are not described in detail here. The differences include:

[0069] Specifically, in this embodiment, the characteristic pattern is a periodic pattern, and the characteristic pattern includes a plurality of periodic units having periodicity along the first measurement direction, and the first characteristic point and the second characteristic point are both points on the periodic unit;

[0070] In this embodiment, the method further includes: obtaining a first characteristic distance between the first characteristic point and the second characteristic point along a first measurement direction;

[0071] Acquiring an image of the characteristic pattern of the first point to be measured by an acquisition unit to obtain a first positioning image; acquiring an image of the characteristic pattern of the second point to be measured by the acquisition unit to obtain a second positioning image; after acquiring the first positioning image, the method further includes: moving the substrate to be measured relative to the detection field of view of the acquisition unit by a first movement distance;

[0072] After moving the first moving distance, an image of the characteristic pattern of the second point to be measured is obtained to obtain a second positioning image; obtaining a first characteristic distance between the first characteristic point and the second characteristic point along the first measurement direction includes: measuring the distance between the detection field of view of the acquisition unit and the relative movement of the substrate to be measured along the measurement direction to obtain the first moving distance; obtaining the number of periods of the first moving distance according to the first moving distance and the period of the characteristic pattern, the number of periods being a maximum integer less than or equal to the ratio of the first moving distance to the period of the characteristic pattern; and obtaining the first characteristic distance according to the product of the number of periods and the period of the characteristic pattern.

[0073] Specifically, obtaining a first target distance between the first to-be-measured point and the second to-be-measured point along the first measurement direction according to the first displacement, the second displacement, and the first characteristic distance includes: obtaining the first target distance according to equation (3): L = N* d + c (3)

[0074] Wherein, L is the first target distance, N is the number of periods between the first feature point and the second feature point, d is the period of the fringe pattern, and c is the sum of the first displacement and the second displacement.

[0075] In this embodiment, the distance between the detection field of view of the acquisition unit and the substrate to be measured and the relative movement along the measuring direction is measured to obtain the first movement distance, including: moving the detection field of view of the acquisition unit and the substrate to be measured relative to each other until the first position of the second feature point in the detection field of view is the same as the second position of the first feature point in the detection field of view; measuring, by a measuring unit, the relative movement distance between the detection field of view and the substrate to be measured during the process of relative movement from the first position to the second position as the first movement distance; the measuring unit includes a grating ruler.

[0076] The first position and the second position being the same can increase detection accuracy. In other embodiments, the first position and the second position can be different, and the difference between the first position and the second position is less than one period of the stripe pattern.

[0077] In other embodiments of the present invention, if the difference between the distance between the first point to be measured and the second point to be measured and the first characteristic distance is less than the size of the field of view of the acquisition unit along the first measurement direction, and the first characteristic distance is a known design value, then based on the first displacement, the second displacement and the first characteristic distance, the first target distance between the first point to be measured and the second point to be measured along the first measurement direction is obtained, including: obtaining the first target distance according to L=d3+x, wherein L is the first target distance, d3 is the design value, and x is the sum of the first displacement and the second displacement. The illumination of the above specific embodiment is a stripe pattern, so only the accurate distance between the first defect and the second defect in the first measurement method of the stripe pattern, that is, perpendicular to the direction in which the stripes extend, can be obtained.

[0078] In a third embodiment of the present invention, the characteristic pattern further includes a third characteristic point and a fourth characteristic point identifiable in the second measurement direction, and the distance between the third characteristic point and the fourth characteristic point along the second measurement direction is a second characteristic distance; an image of the characteristic pattern of the third test point is acquired to obtain a third positioning image; an image of the characteristic pattern of the fourth test point is acquired to obtain a fourth positioning image; a third distance between the first test point and the third characteristic point along the second measurement direction is acquired based on the third positioning image; a fourth distance between the second test point and the fourth characteristic point along the second measurement direction is acquired based on the fourth positioning image; and a second target distance between the first test point and the second test point along the second measurement direction is acquired based on the third distance, the fourth distance, and the second characteristic distance. Furthermore, a two-dimensional spatial distance between the first test point and the second test point is acquired based on the first target distance and the second target distance. In one embodiment, if it is necessary to obtain the distance between the first defect and the second defect on the two-dimensional surface of the substrate, it is necessary to rotate the angle of the structured light, for example, by 90°, to obtain the distances in two directions, and then obtain the distance between the first defect and the second defect on the two-dimensional surface of the substrate through angle calculation.

[0079] In other embodiments, the characteristic pattern may be an array of rectangular patterns, and the first measurement direction and the second measurement direction are parallel to two sides of the rectangular pattern.

[0080] The above description is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for detecting a substrate to be tested, characterized in that: The surface of the substrate to be tested has a first point to be tested and a second point to be tested, and the detection method includes: Performing a displacement measurement process on the substrate to be measured using a characteristic pattern, the displacement measurement process comprising: forming a characteristic pattern at a first point to be measured and a second point to be measured on the surface of the substrate to be measured, wherein the characteristic pattern includes a first characteristic point and a second characteristic point identifiable in a first measuring direction, and a distance between the first characteristic point and the second characteristic point along the first measuring direction is a first characteristic distance; Acquire an image of the characteristic pattern of the first point to be measured to obtain a first positioning image; Acquire an image of the characteristic pattern of the second point to be measured to obtain a second positioning image; Acquire a first displacement between the first point to be measured and the first feature point along a first measurement direction according to the first positioning image, wherein the direction in which the second feature point points toward the first feature point is a positive direction of the first displacement; Acquire a second displacement between the second point to be measured and the second feature point along the first measurement direction according to the second positioning image, where the direction from the first feature point to the second feature point is the positive direction of the second displacement; A first target distance between the first point to be measured and the second point to be measured along the first measurement direction is acquired according to the first displacement, the second displacement and the first characteristic distance.

2. The method according to claim 1, characterized in that The first characteristic distance is a known design value; or the characteristic pattern is a periodic pattern, the characteristic pattern includes a plurality of periodic units having periodicity along the first measurement direction, and the first characteristic point and the second characteristic point are both points on the periodic unit; The method further includes: acquiring a first characteristic distance between the first characteristic point and the second characteristic point along a first measurement direction; Acquiring an image of the characteristic pattern of the first point to be measured by an acquisition unit to obtain a first positioning image; acquiring an image of the characteristic pattern of the second point to be measured by the acquisition unit to obtain a second positioning image; after acquiring the first positioning image, the method further includes: moving the substrate to be measured relative to the detection field of view of the acquisition unit by a first movement distance; After moving the first moving distance, an image of the characteristic pattern of the second point to be measured is obtained to obtain a second positioning image; obtaining a first characteristic distance between the first characteristic point and the second characteristic point along the first measurement direction includes: measuring the distance between the detection field of view of the acquisition unit and the relative movement of the substrate to be measured along the measurement direction to obtain the first moving distance; obtaining the number of periods of the first moving distance according to the first moving distance and the period of the characteristic pattern, the number of periods being a maximum integer less than or equal to the ratio of the first moving distance to the period of the characteristic pattern; and obtaining the first characteristic distance according to the product of the number of periods and the period of the characteristic pattern.

3. The method according to claim 2, characterized in that Measuring the relative movement distance between the detection field of view of the acquisition unit and the substrate to be measured along the measuring direction to obtain a first movement distance includes: moving the detection field of view of the acquisition unit and the substrate to be measured relative to each other until a first position of the second feature point in the detection field of view is the same as a second position of the first feature point in the detection field of view; measuring, by a measuring unit, the relative movement distance between the detection field of view and the substrate to be measured during the relative movement from the first position to the second position as the first movement distance; the measuring unit includes a grating ruler.

4. The method according to claim 2, characterized in that Acquiring a first displacement between a first point to be measured and a first feature point along a first measurement direction according to the first positioning image, comprising: acquiring a periodic unit with a minimum distance from the first point to be measured as a first feature point according to the first positioning image; acquiring a relative displacement between the first feature point and the first point to be measured along the first measurement direction to obtain the first displacement; Obtaining a second displacement between the second point to be measured and the second feature point along the first measurement direction according to the second positioning image, including: obtaining a periodic unit with the smallest distance from the second point to be measured as the second feature point according to the second positioning image; obtaining the relative displacement between the second feature point and the second point to be measured along the first measurement direction to obtain the second displacement, and the direction from the first feature point to the second feature point is the positive direction of the second displacement.

5. The method according to any one of claims 1 to 4, characterized in that Performing multiple displacement measurement processes on the substrate to be measured using a characteristic pattern; The first characteristic distances between the first characteristic point and the second characteristic point in the characteristic pattern during the multiple displacement measurement processes are different, and the first characteristic distances during the multiple displacement measurement processes have a preset relationship; Acquiring a first target distance between the first point to be measured and the second point to be measured along the first measurement direction according to the first displacement, the second displacement, and the first characteristic distance, including: The first target distance is acquired according to the distance relationship processed by multiple position measurements and the preset relationship, wherein the distance relationship includes: the sum of the first displacement, the second displacement and the first characteristic distance is equal to the first target distance.

6. The method according to claim 5, characterized in that The preset relationship is: the difference or sum of the first characteristic distances processed by multiple displacement measurements is a preset value; or, If the characteristic pattern is a periodic pattern, the period of the characteristic pattern along the first measurement direction is different in multiple displacement measurement processes; the first characteristic point is a periodic unit with the smallest distance from the first point to be measured, and the first characteristic point is a periodic unit with the smallest distance from the second point to be measured; The first characteristic distance is an integer multiple of the period; The preset relationship includes: the integer multiples of the first characteristic distance processed in multiple displacement measurements are the same.

7. The method according to claim 6, characterized in that The characteristic pattern is a periodic pattern; According to the distance relationship processed by multiple position measurements and the preset relationship, the first target distance is obtained, including: obtaining the first target distance L according to equation (1), L=N*d1+a; L=N*d2+b(1); Where L is the first target distance, d1 is the period of the characteristic pattern in the first displacement measurement process, d2 is the period of the characteristic pattern in the second displacement measurement process; a is the sum of the first displacement and the second displacement in the first displacement measurement process, b is the sum of the first displacement and the second displacement in the second displacement measurement process, and N is the number of fringes between the first feature point and the second feature point.

8. The method according to claim 6, characterized in that The sum of the first characteristic distances processed by multiple displacement measurements is a preset value y; Obtaining the first target distance according to the distance relationship processed by multiple position measurements and the preset relationship includes: obtaining the first target distance L according to equation (2): L=(y+a+b) / 2(2).

9. The method according to claim 2, characterized in that The characteristic pattern further includes a third characteristic point and a fourth characteristic point identifiable in the second measurement direction, and the distance between the third characteristic point and the fourth characteristic point along the second measurement direction is a second characteristic distance; Acquire an image of the characteristic pattern of the third point to be measured to obtain a third positioning image; Acquire an image of the characteristic pattern of the fourth point to be measured to obtain a fourth positioning image; Acquire a third distance between the first point to be measured and the third feature point along the second measurement direction according to the third positioning image; Acquire a fourth distance between the second point to be measured and the fourth feature point along the second measurement direction according to the fourth positioning image; A second target distance between the first point to be measured and the second point to be measured along the second measurement direction is acquired according to the third distance, the fourth distance and the second characteristic distance.

10. The method according to claim 9, characterized in that include: A two-dimensional spatial distance between the first point to be measured and the second point to be measured is obtained according to the first target distance and the second target distance.

11. A detection device for executing the detection method according to any one of claims 1 to 10, characterized in that: The surface of the substrate to be measured has a first point to be measured and a second point to be measured, and the device includes: a transmitting unit, wherein the transmitting unit transmits a characteristic pattern to the substrate to be measured and performs a displacement measurement process on the substrate to be measured, wherein the displacement measurement process includes: forming a characteristic pattern at a first point to be measured and a second point to be measured on the surface of the substrate to be measured, the characteristic pattern including a first characteristic point and a second characteristic point identifiable in a first measurement direction, and a distance between the first characteristic point and the second characteristic point along the first measurement direction is a first characteristic distance; an acquisition unit, the acquisition unit acquiring an image of a characteristic pattern formed by the emitting unit at the first point to be measured to obtain a first positioning image; acquiring an image of a characteristic pattern formed by the emitting unit at the second point to be measured to obtain a second positioning image; and A processing unit, wherein the processing unit obtains a first displacement between the first point to be measured and the first feature point along the first measurement direction based on the first positioning image obtained by the acquisition unit, and the direction in which the second feature point points to the first feature point is the positive direction of the first displacement; obtains a second displacement between the second point to be measured and the second feature point along the first measurement direction based on the second positioning image, and the direction in which the first feature point points to the second feature point is the positive direction of the second displacement; and obtains a first target distance between the first point to be measured and the second point to be measured along the first measurement direction based on the first displacement, the second displacement and the first feature distance.

12. The device according to claim 11, characterized in that The emitting unit includes a light source and a pattern element, and the light source emits a light beam to the pattern element to project a pattern of the pattern element onto the substrate to be measured; or the emitting unit includes a display screen.

13. The device according to claim 11, characterized in that The first characteristic distance is a known design value; or the characteristic pattern is a periodic pattern, the characteristic pattern includes a plurality of periodic units having periodicity along the first measurement direction, and the first characteristic point and the second characteristic point are both points on the periodic unit; The acquisition unit acquires a first characteristic distance between the first characteristic point and the second characteristic point along a first measurement direction; Acquire an image of the characteristic pattern of the first point to be measured by an acquisition unit to obtain a first positioning image; Acquire an image of the characteristic pattern of the second point to be measured by the acquisition unit to obtain a second positioning image; After acquiring the first positioning image, the method further includes: moving the substrate to be measured and the detection field of view of the acquisition unit relative to each other by a first moving distance; After the acquisition unit and the substrate to be measured are moved relative to each other by a first movement distance, an image of the characteristic pattern of the second point to be measured is acquired by the acquisition unit to obtain a second positioning image; Obtaining a first characteristic distance between the first characteristic point and the second characteristic point along the first measurement direction includes: measuring the distance between the detection field of view of the acquisition unit and the relative movement of the substrate to be measured along the measurement direction to obtain a first movement distance; obtaining the number of periods of the first movement distance based on the first movement distance and the period of the characteristic pattern, where the number of periods is a maximum integer less than or equal to the ratio of the first movement distance to the period of the characteristic pattern; and obtaining the first characteristic distance based on the product of the number of periods and the period of the characteristic pattern.

14. The device according to claim 13, characterized in that Measuring the relative movement distance between the detection field of view of the acquisition unit and the substrate to be measured along the measuring direction to obtain a first movement distance includes: moving the detection field of view of the acquisition unit and the substrate to be measured relative to each other until a first position of the second feature point in the detection field of view is the same as a second position of the first feature point in the detection field of view; measuring, by a measuring unit, the relative movement distance between the detection field of view and the substrate to be measured during the relative movement from the first position to the second position as the first movement distance; the measuring unit includes a grating ruler.

15. The device according to any one of claims 10 to 14, characterized in that: Performing multiple displacement measurement processes on the substrate to be measured using a characteristic pattern; The first characteristic distances between the first characteristic point and the second characteristic point in the characteristic pattern during the multiple displacement measurement processes are different, and the first characteristic distances during the multiple displacement measurement processes have a preset relationship; Acquiring a first target distance between the first point to be measured and the second point to be measured along the first measurement direction according to the first displacement, the second displacement, and the first characteristic distance, including: The first target distance is acquired according to the distance relationship processed by multiple position measurements and the preset relationship, wherein the distance relationship includes: the sum of the first displacement, the second displacement and the first characteristic distance is equal to the first target distance.

16. The device according to claim 11, characterized in that The characteristic pattern generated by the transmitting unit further includes a third characteristic point and a fourth characteristic point identifiable in the second measuring direction, and the distance between the third characteristic point and the fourth characteristic point along the second measuring direction is a second characteristic distance; The acquisition unit acquires an image of the characteristic pattern of the third point to be measured to obtain a third positioning image; Acquire an image of the characteristic pattern of the fourth point to be measured to obtain a fourth positioning image; The processing unit obtains a third distance between the first point to be measured and the third feature point along the second measurement direction based on the third positioning image; obtains a fourth distance between the second point to be measured and the fourth feature point along the second measurement direction based on the fourth positioning image; obtains a second target distance between the first point to be measured and the second point to be measured along the second measurement direction based on the third distance, the fourth distance and the second feature distance; the feature pattern includes an array formed by rectangular patterns.

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