WO2020001633A1

WO2020001633A1 - Defect inspection apparatus and defect inspection method

Info

Publication number: WO2020001633A1
Application number: PCT/CN2019/093779
Authority: WO
Inventors: 杨晓青; 申永强; 韩雪山; 王帆
Original assignee: 上海微电子装备（集团）股份有限公司
Priority date: 2018-06-29
Filing date: 2019-06-28
Publication date: 2020-01-02
Also published as: TW202001232A; CN110658196A; CN110658196B; TWI728386B

Abstract

A defect inspection apparatus and a defect inspection method. The defect inspection apparatus comprises an illumination module (20) and an imaging inspection module (30). The illumination module (20) is configured to generate a detection light beam (201), and to make the detection light beam (201) incident to the inspection surface of a product to be inspected (40). The imaging inspection module (30) is configured to detect whether the detection light beam (201) is scattered by the inspection surface of said product (40) so as to generate a scattered imaging light beam (301), and if detecting the scattered imaging light beam (301), to determine defect information of said product (40) according to the scattered imaging light beam (301). The illuminance of the detection light beam (201) satisfies: (U1×R)/(U2×L)≥S1, wherein S1 is a signal-to-noise ratio needing to be satisfied to suppress crosstalk on the non-inspection surface of said product (40), U1 is the central illuminance of the detection light beam (201), R is the scattering efficiency of light by the minimum inspectable defect at a receivable angle, U2 is the illuminance of the half-width edge of the detection light beam (201), and L is the scattering efficiency of light by the maximum crosstalk object on the non-detection surface at a receivable angle. The half width W of the detection light beam (201) satisfies: d×(tanα+tanβ)>FOV/2+W, wherein d is the thickness of said product (40), FOV is an effective field of view of the imaging inspection module (30), α is the angle of refraction of the detection light beam (201) in said product (40), and β is the angle of refraction of the scattered imaging light beam (301) in said product (40).

Description

Defect detection device and method

This application claims priority from a Chinese patent application filed with the Chinese Patent Office on June 29, 2018 with application number 201810696844.2, the entire contents of which are incorporated herein by reference.

Technical field

The embodiments of the present application relate to the technical field of defect detection, for example, to a defect detection device and a defect detection method.

Background technique

In the manufacturing process of semiconductor integrated circuits or flat panel displays, in order to maintain a high yield of the product, defects (including foreign particles, fingerprints, scratches, pinholes, etc.) need to be performed before exposing the reticle or glass substrate. Etc.) to achieve the purpose of controlling pollution.

FIG. 1 is a schematic structural diagram of a defect detection device in the related art. A particle detection device generally integrated in a lithographic apparatus generally adopts a dark field scattering measurement technology. The detection principle is shown in FIG. The light 101 is scattered by the defect 114 on the object to be measured 104, and the scattered light 102 is finally detected by the detector 103, and then the size of the defect is determined according to the scattered light detected by the detector 103.

However, during the defect detection process of the defect detection device in the related art, the lower surface pattern of the product to be tested is prone to generate crosstalk signals, which affects the accuracy of the defect detection result.

Summary of the invention

The application provides a defect detection device and a defect detection method, so as to achieve the suppression of crosstalk generated during the defect detection process.

In a first aspect, an embodiment of the present application provides a defect detection device, including an illumination module and an imaging detection module;

The lighting module is configured to generate a detection beam;

The imaging detection module is configured to detect whether the detection beam is scattered by a detection surface of a product to be measured to generate a scattered imaging beam, and when the scattered imaging beam is detected, determine the to-be-measured according to the scattered imaging beam. Product defect information;

The illuminance of the detection beam satisfies:

Among them, S1 is the signal-to-noise ratio required to suppress crosstalk on the non-detection surface of the product under test, U1 is the central illuminance of the detection beam, and R is the scattering efficiency of light by the smallest detectable defect within the receivable angle. , U2 is the illuminance at the half-width edge of the detection beam, and L is the scattering efficiency of the maximum crosstalk on the non-detection surface to the light within a receivable angle;

The half-width W of the detection beam satisfies:

Where d is the thickness of the product to be measured; FOV is the effective field of view of the imaging detection module; α is the refraction angle of the detection beam in the product to be measured; β is the scattering imaging beam in the object to be measured Measure the refraction angle in the product.

In an embodiment, the illuminance of the detection beam further satisfies:

Among them, S2 is the signal-to-noise ratio required for suppressing the image crosstalk, M is the scattering efficiency of the detection beam in the image crosstalk direction in the image crosstalk area, and N is the scattered light in the image crosstalk direction in the illumination field Describe the reflectivity in the product to be tested;

The half-width W of the detection beam also satisfies:

Where θ is the refraction angle of the scattered light of the detection beam in the direction of mirror crosstalk in the product to be measured.

In an embodiment, the angular deviation of the main ray of the detection beam is less than 5 °; the angular deviation of the main ray of the scattered imaging beam is less than 5 °.

In an embodiment, the above-mentioned defect detection device further includes: a horizontal movement module; the horizontal movement module is configured to carry the product to be tested to move in a direction parallel to the detection surface of the product to be tested.

In one embodiment, the defect detection device further includes: a focal plane measurement module and a vertical movement module;

The focal plane measurement module is configured to detect a defocus amount of a detection plane of the product to be measured;

The vertical movement module is configured to control the product to be measured to move in a direction perpendicular to the detection surface according to the defocus amount.

In an embodiment, the imaging detection module is configured to determine defect information of the product to be tested according to the scattered imaging beam by determining multiple imaging signals based on the scattered imaging beams obtained multiple times in succession, and The plurality of imaging signals are integrated to determine the defect information.

In one embodiment, the imaging detection module includes an integration camera; the integration camera is a Time Delay Integration (TDI), a Complementary Metal Oxide Semiconductor (CMOS) camera, or a charge coupled device Element (charge coupled device, CCD) camera.

In an embodiment, the imaging detection module further includes a light condensing unit, and the light condensing unit is configured to converge the scattered imaging light beam so that the converged scattered imaging light beam enters the integrating camera.

In one embodiment, the detection beam satisfies a Gaussian distribution.

In a second aspect, an embodiment of the present application further provides a lithographic apparatus including the defect detection device described in the first aspect.

In a third aspect, an embodiment of the present application further provides a defect detection method, including:

A detection beam is generated by the lighting module, and the detection beam is made incident on the detection surface of the product to be tested; the illuminance of the detection beam and the half-width of the detection beam satisfy:

Detecting whether the detection beam is scattered by the detection surface of the product to be tested by the imaging detection module to generate a scattered imaging beam, and determining the defect information according to the imaging light when the scattered imaging beam is detected;

Among them, S1 is the signal-to-noise ratio required to suppress crosstalk on the non-detection surface of the product under test, U1 is the central illuminance of the detection beam, and R is the scattering efficiency of light by the smallest detectable defect within the receivable angle. , U2 is the illuminance at the half-width edge of the detection beam, L is the scattering efficiency of the maximum crosstalk on the non-detecting surface within the receivable angle, and d is the thickness of the product under test; FOV is The effective field of view of the imaging detection module; α is the refraction angle of the detection beam in the product to be measured, and β is the refraction angle of the scattered imaging beam in the product to be measured.

In an embodiment, determining the defect information according to the scattered imaging beam includes:

Determining a plurality of imaging signals according to the scattered imaging beams obtained multiple times in succession;

Integrating the plurality of imaging signals to determine the defect information.

The embodiment of the present application uses the minimum detectable defect to scatter the light in the receivable angle, the maximum crosstalk on the non-detection surface to scatter the light in the receivable angle, and suppresses the non-detection surface of the product to be tested. The required signal-to-noise ratio of the crosstalk is to obtain the contrast between the half-width edge of the detection beam and the center of the detection beam; the refraction angle of the detection beam in the product to be tested and the refraction angle of the scattered imaging beam in the product to be tested , The thickness of the product to be tested and the effective field of view of the imaging detection module to obtain the half-width of the detection beam that can satisfy the crosstalk of the non-detection surface of the product to be tested; the lighting module can be determined according to the contrast and the half-width of the detection beam By setting a lighting module that satisfies the above parameters, the defect detection device in the embodiment of the present application can suppress crosstalk generated during the defect detection process and improve the accuracy of defect detection.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic structural diagram of a defect detection device in the related art;

2 is a schematic structural diagram of a defect detection device according to an embodiment of the present application;

3 is a schematic structural diagram of a half width of a detection beam provided by an embodiment of the present application;

4 is a schematic diagram of a lower-layer crosstalk provided by an embodiment of the present application;

5 is a schematic diagram of image crosstalk provided by an embodiment of the present application;

6 is a schematic structural diagram of a detection beam provided by an embodiment of the present application;

7 is a schematic structural diagram of a scattered imaging beam and an imaging detection module according to an embodiment of the present application;

8 is a schematic structural diagram of another defect detection device according to an embodiment of the present application;

FIG. 9 is a schematic diagram of a positional relationship between a detection beam and a defect according to an embodiment of the present application; FIG.

FIG. 10 is a flowchart of a defect detection method according to an embodiment of the present application.

detailed description

The following describes the application with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present application, rather than limiting the present application. It should also be noted that, for convenience of description, the drawings only show a part of the structure related to the present application, but not the entire structure.

FIG. 2 is a schematic structural diagram of a defect detection device according to an embodiment of the present application. Please refer to FIG. 2, the device includes an illumination module 20 and an imaging detection module 30; the illumination module 20 is configured to generate a detection beam 201 and make the detection beam 201 incident on The detection surface of the product to be tested 40; the imaging detection module 30 is configured to detect whether the detection beam 201 is scattered by the detection surface of the product 40 to generate a scattered imaging beam 301, and if the scattered imaging beam 301 is detected, the imaging is performed according to the scattering imaging The light beam 301 determines defect information of the product to be tested 40.

The illuminance of the detection beam 201 satisfies:

Among them, S1 is the signal-to-noise ratio required to suppress crosstalk on the non-detection surface of the product 40 to be tested, U1 is the central illuminance of the detection beam 201, and R is the light scattering efficiency of the smallest detectable defect within the receivable angle, U2 In order to detect the illuminance at the half-width edge of the beam 201, L is the scattering efficiency of the largest crosstalk on the non-detection surface to the light within the receivable angle. The half-width W of the detection beam 201 satisfies

Among them, d is the thickness of the product to be tested 40; FOV is the effective field of view of the imaging detection module 30; α is the refraction angle of the detection beam 201 in the product to be tested 40; β is the scattering imaging beam 301 in the product to be tested 40 Refraction angle.

In one embodiment, the light generated by the lighting module 20 forms a detection beam 201 on the product 40 to be tested. If the detection beam 201 does not meet the defect 401 on the detection surface of the product to be tested 40, according to the law of light reflection, the detection beam 201 forms a reflection beam 202 on the detection surface of the product 40 to be tested. The reflection beam 202 usually cannot enter the imaging detection module 30. . If the detection beam 201 encounters a defect 401 on the detection surface of the product to be tested 40, the defect 401 will cause a scattering effect of the light, and a part of the scattered light can enter the imaging detection module 30, such as a scattered imaging beam 301. The imaging detection module 30 can determine the defect information on the product 40 to be tested, such as the size of the defect, based on the scattered imaging beam 301. The testing surface of the product 40 to be tested refers to the surface of the product 40 to be tested close to the lighting module 20, and the defect 401 is usually located on the testing surface of the product 40 to be tested. The non-testing surface of the product 40 to be tested refers to the product 40 to be tested. The detection surface is opposite to the set surface.

FIG. 3 is a schematic structural diagram of a half width of a detection beam provided by an embodiment of the present application. In an embodiment, please refer to FIG. 2 and FIG. 3. For a Gaussian beam, the center of the beam is larger on the detection surface of the product 40 to be tested, and the half-width edge of the beam is on the detection surface of the product 40 to be tested. The resulting illumination is small. The half-width edge of the light beam can generally be set as required. For example, the position of the illuminance at 1 / 100th of the illuminance at the center of the beam can be set to the half-width edge of the beam, or the illuminance at the center of the beam. The position of 1/10000 is set to the half-width edge of the beam, which is not specifically limited in this embodiment.

FIG. 4 is a schematic diagram of a lower-layer crosstalk provided by an embodiment of the present application. In an embodiment, please refer to FIG. 2 and FIG. 4. The lower layer crosstalk refers to the crosstalk caused by the crosstalk 402 on the non-detection surface of the product 40 to be tested. The non-detection surface of the product under test 40 may include a crosstalk 402. When the product under test 40 is a mask, the crosstalk 402 may be a grating with a periodic structure. The detection beam 201 includes a ray 2011 at the center of the detection beam 201 and a ray 2012 at the half-width edge of the detection beam 201. In the case of detecting a defect, the ray 2011 at the center of the detection beam 201 is preferentially used as the detection ray to detect the defect 401. After the central ray 2011 of the detection beam 201 is scattered by the defect 401, the scattered imaging beam 301 formed is received by the imaging detection module 30. At this time, if the half-width edge light 2012 of the detection beam 201 is refracted by the product to be measured 40 and falls within the effective range of the effective field of view FOV of the imaging detection module 30, after being scattered by the crosstalk 402, a crosstalk signal can be formed and Detected by the imaging detection module 30.

In order to suppress the crosstalk signal on the non-detection surface of the product to be tested 40 and to prevent the crosstalk signal from affecting the defect detection result, the illuminance of the detection beam 201 needs to be controlled within a certain range. The illuminance of the detection beam 201 can satisfy

In an embodiment, R may be determined according to the size of the smallest detectable defect, the position of the lighting module 20 and the imaging detection module 30; L may be determined according to the positions of the lighting module 20 and the imaging detection module 30, and the size of the maximum crosstalk, etc. Parameters are determined. According to this, the ratio of the illuminance U2 of the half-width edge of the detection beam 201 and the central illuminance U1 of the detection beam 201 can be determined according to the above formula.

That is, determine the contrast between the central illuminance and the half-width edge illuminance.

In addition, the half-width W of the detection beam 201 satisfies:

For the determined defect detection device and the product to be tested 40, the effective field of view FOV of the imaging detection module 30 is determined. The refraction angle α of the detection beam 201 in the product to be tested 40 and the scattered imaging beam 301 in the product to be tested 40 The refraction angle β in can be determined according to the positions of the illumination module 20 and the imaging detection module 30, and accordingly, the half-width W of the detection beam 201 can be determined according to the above formula. It can be understood that after determining the half-width W of the detection beam 201 and the ratio of the illuminance U2 of the half-width edge of the detection beam 201 to the central illuminance U1 of the detection beam 201, the detection beam 201 can be uniquely determined. By adjusting the lighting module 20 Can obtain a detection beam 201 capable of suppressing crosstalk of the lower layer.

This embodiment uses the minimum detectable defect to scatter the light in the receivable angle, the maximum crosstalk on the non-detection surface to scatter the light in the receivable angle, and suppresses the non-detection surface of the product to be tested. The signal-to-noise ratio required for crosstalk to obtain the contrast between the half-width edge of the detection beam and the center of the detection beam; the refraction angle of the detection beam in the product under test, the refraction angle of the scattered imaging beam in the product under test, The thickness of the product to be tested and the effective field of view of the imaging detection module can be used to obtain the half-width of the detection beam required to suppress crosstalk on the non-detection surface of the product under test; For specific parameters, by setting a lighting module that meets the above parameters, the defect detection device in the embodiment of the present application can suppress crosstalk generated during the defect detection process and improve the accuracy of defect detection.

In an embodiment, in order to improve the detection sensitivity, the imaging detection module 30 of this embodiment determines the defect information by receiving the scattered light of the defect, that is, using dark field imaging. The refraction angle α of the detection beam 201 in the product 40 to be measured is usually not It is equal to the refraction angle β of the scattered imaging light beam 301 in the product 40 to be measured, that is, α ≠ β. Exemplarily, when the thickness d of the product 40 to be measured is 6.35 millimeters (mm), the value of the refraction angle α satisfies 30 ° <α <45 °, and the refraction angle β satisfies 30 ° <β <45 °. In one embodiment, in order to obtain better detection results, | α-β |> 3.5 °. Exemplarily, if FOV = 1.5mm, α = 42 °, β = 35 °, and d = 6.35mm, then

In order to obtain clear detection results, S1 = 3, L = 3333.3 × R, then

If the detection beam 201 satisfies an ideal Gaussian function, the detection beam 201 can be uniquely determined if the relative contrast is known as a maximum value of 1/10000 and the half-width W of the detection beam 201 is 9.41 mm. At this time, the half-width and half-width of the detection beam 201 (the half-width of the illumination field of view of 50% contrast) is W1 = 2.97 mm, and the full-width at half height of the detection beam 201 is W _FWHM = 2 × W1 = 5.94 mm.

In an embodiment, the illuminance of the detection beam 201 also satisfies:

Among them, S2 is the signal-to-noise ratio required for suppressing the image crosstalk, M is the scattering efficiency of the detection beam 201 in the image crosstalk direction in the image crosstalk area, and N is the scattered light of the detection beam 201 in the image crosstalk direction in the product under test 40. Reflectivity; the half-width W of the detection beam 201 also satisfies:

Where, θ is the refraction angle of the scattered light of the detection beam 201 along the direction of the image crosstalk in the product 40 to be measured.

FIG. 5 is a schematic diagram of image crosstalk provided by an embodiment of the present application. In an embodiment, please refer to FIG. 2 and FIG. 5. After the center ray 2011 of the detection beam 201 encounters the first defect 4011, it forms a scattered imaging beam 301. The imaging detection module 30 can determine the product to be tested according to the scattered imaging beam 301. 40 defect information. After the edge light 2012 of the detection beam 201 is scattered by the second defect 4012 on the detection surface of the product 40 to be tested, the scattered light enters the product 40 to be tested and forms a reflection after being reflected on the non-detection surface of the product 40 to be tested. It can be understood that the defect currently being detected by the defect detection device is the first defect 4011. If the light generated by the reflection of the second defect 4012 enters the effective field of view FOV of the imaging detection module 30, a mirror crosstalk signal will be formed. The detection result of the first defect 4011 forms crosstalk, which is called mirror crosstalk. If the intensity of the image crosstalk signal is large, the clarity and accuracy of the detection of the first defect 4011 will be affected.

In order to suppress image crosstalk, the illuminance of the detection beam 201 needs to satisfy:

And make the half-width W of the detection beam 201 satisfy:

Generally, the larger the size of the defective particles in the mirror crosstalk region on the detection surface of the product 40 to be tested, the larger the value of M is. For the determined product 40 to be tested, the M value can be determined after the positions and angles of the lighting module 20 and the imaging detection module 30 and the size of the largest defect are determined. The reflectance N of the detection beam in the product under test 40 is related to the refractive index of the product under test 40. Exemplarily, the detection beam enters the product under test 40 from the air, and is refracted and reflected, and then exits from the product under test 40 into the air again. Since the refractive index n1 of the air is usually 1, 1.5, then the reflectance N = (n2-n1) ² / (n2 + n1) ² = (1.5-1) ² /(1.5+1) ² = 0.04.

The half-width of the detection beam 201 can be determined according to the refraction angle θ of the scattered light of the detection beam 201 in the image crosstalk direction in the product to be tested, the thickness d of the product 40 to be tested, and the effective field of view FOV of the imaging detection module 30. W. It can be understood that after determining the half-width W of the detection beam 201 and the ratio of the illuminance U2 of the half-width edge of the detection beam 201 to the central illuminance U1 of the detection beam 201, the detection beam 201 can be uniquely determined. By adjusting the lighting module, 20 working parameters, a detection beam 201 capable of suppressing image crosstalk can be obtained.

Exemplarily, it is known that the scattered light intensity of standard defect particles of 250 micrometers (μm) is 625 times of that of standard defect particles of 10 μm. Let the detection beam 201 satisfy the ideal Gaussian distribution. In order to ensure that 100 μm standard defect particles do not cause mirror crosstalk, The refractive index n of the detection beam 201 in the product under test 40 is 1.5, then the reflectance N of the scattered light of the detection beam 201 in the image crosstalk direction in the product under test 40 is 0.04, and the scattered light of the detection beam 201 in the image crosstalk direction is The refractive index refraction angle θ = 35 ° in the product to be tested 40, and the signal-to-noise ratio S2 = 4 that needs to be satisfied to suppress image crosstalk.

Set the thickness of the product to be tested d = 6.35mm, FOV = 1.5mm, then the half-width of the detection beam 201

The detection beam 201 can be uniquely determined according to the relative contrast determined by the ratio U2 / U1 of the illuminance U2 of the half-width edge of the detection beam 201 and the central illuminance U1 of the detection beam 201, and the value of the half-width W of the detection beam 201.

FIG. 6 is a schematic structural diagram of a detection beam provided by an embodiment of the present application. In an embodiment, please refer to FIG. 6, the angular deviation of the main ray of the detection beam 201 is less than 5 °; the angular deviation of the main ray of the scattered imaging beam is less than 5 °. In an embodiment, the detection beam 201 emitted from the lighting module forms an illumination field of view 103 on the detection surface of the product 40 to be tested. To ensure the accuracy of defect detection, the emission directions of the detection beam 201 need to be the same as much as possible. The main ray of the detection beam 201 refers to the ray near the center of the field of view. Generally, when the angle deviation of the main ray of the detection beam 201 is less than 5 °, a more accurate defect detection result can be obtained. When the deviation is less than 1 °, more accurate measurement results can be obtained. Exemplarily, when a light beam with a wavelength of 640 nanometers (nm) is used as the detection beam 201 to detect a standard defect particle of 20um, when the deviation of the scattering efficiency of the detection beam 201 with the angle of the detection beam 201 is 10 °, the scattering The difference in efficiency is as high as 61.3%. Since the scattered light generated by defects may be in any direction, this difference cannot be corrected, resulting in inaccurate defect detection results.

FIG. 7 is a schematic structural diagram of a scattered imaging beam and an imaging detection module according to an embodiment of the present application. In an embodiment, please refer to FIGS. 2 and 7, since the probe imaging beam 201 is scattered by the defect 401, the direction of the scattered imaging beam 301 formed is arbitrary. The scattered imaging light beam 301 that can enter the imaging detection module 30 includes first imaging light 3010, second imaging light 3011, and third imaging light 3012 in different directions. Among them, the first imaging light 3010 is closest to being perpendicular to the imaging detection module 30. The surface of the imaging light 301. Therefore, the first imaging light 3010 is a main light that scatters the imaging light beam 301. The angular deviation of the main ray of the scattered imaging beam 301 should also be less than 5 °. In an embodiment, the angular deviation of the main ray of the scattered imaging beam 301 may be less than 1 °.

FIG. 8 is a schematic structural diagram of another defect detection device according to an embodiment of the present application. In an embodiment, please refer to FIG. 8, the defect detection device further includes a horizontal movement module 50; the horizontal movement module 50 is configured to carry the product to be tested 40 moving in a direction parallel to the detection surface of the product 40 to be tested. In an embodiment, during the defect detection process, the horizontal movement module 50 drives the product under test 40 to move in a direction parallel to the detection surface of the product under test 40 to realize the scanning detection of the entire product under test 40.

In an embodiment, the defect detection device provided in this embodiment further includes: a focal plane measurement module 70 and a vertical movement module 60; the focal plane measurement module 70 is configured to detect a defocus amount of a detection surface of the product 40 to be measured; and a vertical movement The module 60 is configured to control the product to be tested 40 to move in a direction perpendicular to the detection surface according to the defocus amount. In one embodiment, by measuring the distance between the detection surface of the product to be tested 40 and the focal plane measurement module 70, the defocus amount between the detection surface of the product 40 to be tested and the imaging detection module 30 is obtained. The vertical movement module 60 may be set to adjust the height of the product 40 to be tested, thereby adjusting the relative positions of the product 40 to be tested and the lighting module 20 and the imaging detection module 30 to ensure the accuracy of the defect detection result.

In one embodiment, the imaging detection module 30 is configured to determine the defect information of the product 40 to be tested according to the scattered imaging light beam in the following manner: determining a plurality of imaging signals according to the imaging light rays 301 obtained multiple times in succession, and performing Credits to determine defect information. In order to ensure the accuracy of detection of smaller defective particles, the imaging detection module 30 needs to have a higher spatial resolution. In one embodiment, the spatial resolution of the defect detection device is generally required to be less than 0.1 mm. Still taking the half-height, half-width W1 of the detection beam 201 as 2.97mm as an example, when the spatial resolution is less than 0.2 times of W1, that is, when the spatial resolution is less than 0.2 × 2.97 = 0.594mm, but the detection beam 201 is difficult to achieve the ideal Linear state, focus error of the detection beam 201, fluctuations in the focal plane of the illumination field of view during the detection process, the detection surface of the product to be tested is not completely horizontal, and the movement axis of the horizontal movement module 50 has pitch and roll during the movement Or deflection, etc., causing a large difference in the position of the defect in the illumination field of view, so that there is a large difference in the light energy received and scattered by the defect, so that the result of the defect detection is greatly affected by the aforementioned accidental factors.

FIG. 9 is a schematic diagram of a positional relationship between a detection beam and a defect according to an embodiment of the present application. In an embodiment, please refer to FIG. 9. From t1 to t4, due to the change in the relative position of the defect and the detection beam, the defect at t1 is located at the first position P1, the defect at t2 is located at the second position P2, and the defect is located at t3. The third position P3 and the defect at time t4 are located at the fourth position P4. The defect information collected by the imaging inspection module at different times has a large difference in signal strength, which affects the accuracy and repeatability of the defect detection, and results in defect detection. Unreliable. However, in this embodiment, after integral processing is performed on all signals collected from time t1 to time t4, the total defect detection signal obtained is relatively stable, and detection accuracy and repeatability of detection can be greatly improved. It should be noted that this embodiment only exemplarily integrates signals acquired four times in a row, and is not a limitation on the present application.

In an embodiment, please continue to refer to FIG. 8. The imaging detection module 30 includes an integration camera 302. The integration camera 302 may be a TDI camera, a CMOS camera, or a CCD camera. In one embodiment, the TDI camera is a time-delay integral camera, which can continuously take pictures of moving objects and record the position changes during the movement of the collected objects. The core structure of a CMOS camera is a CMOS element with high resolution, which can be used to record the position information of a moving object. The CCD camera has a high resolution, and in particular when shooting a position or moving, after processing a picture taken by the CCD camera, detailed object moving position information can be obtained. It can be understood that the integration camera 302 may also be another type of camera, which is not specifically limited in this embodiment.

In one embodiment, the imaging detection module 30 further includes a light focusing unit 303. The light focusing unit 303 is configured to converge the imaging light 301 so that the converged imaging light 301 enters the integrating camera 302. After the detection beam 201 is scattered by the defect 401, the formed scattered imaging beam 301 can propagate in any direction, and the light that can enter the imaging detection module 30 is divergent light. In order to facilitate the detection of defect information, it is necessary to focus the divergent scattered imaging beam 301. In an embodiment, the light condensing unit 303 may be a group of lenses, and the number of lenses may be set according to actual needs, which is not specifically limited in this embodiment.

In one embodiment, the detection beam 201 satisfies a Gaussian distribution. In an embodiment, the detection light beam 201 emitted by the lighting module 20 may be a Gaussian light beam. The amplitude of the Gaussian beam changes according to the law of the Gaussian function. The illuminance at the center of the beam is large. From the center of the beam to the edge of the beam, the amplitude of the Gaussian beam decays quickly. Through certain optical adjustment methods, it is easy to obtain a beam with a narrow field of view. Therefore, crosstalk generated during defect detection can be better suppressed, and the accuracy of defect detection can be improved.

This embodiment also provides a lithographic apparatus, which can be the defect detection device described in any embodiment of the present application.

The lithographic equipment provided by this embodiment uses the minimum detectable defect to scatter light in the receivable angle, the maximum crosstalk on the non-detection surface to scatter the light in the receivable angle, and suppresses the test. The signal-to-noise ratio required for crosstalk on the non-detection surface of the product, to obtain the contrast between the half-width edge of the detection beam and the center of the detection beam; the refraction angle of the detection beam in the product to be tested, and the scattered imaging beam in the test to be measured The refraction angle in the product, the thickness of the product to be tested, and the effective field of view of the imaging detection module, obtain the half-width of the detection beam that can meet the crosstalk of the non-detection surface of the product to be tested; The specific parameters of the lighting module can be determined by setting the lighting module that satisfies the above parameters, so that the defect detection device in the embodiment of the present application can suppress crosstalk generated during the defect detection process and improve the accuracy of defect detection.

Based on the defect detection device, this embodiment also provides a defect detection method. The defect detection method provided in this embodiment may be executed by the defect detection device provided in any of the foregoing embodiments, and the defect side detection method has a beneficial effect corresponding to the defect detection device. For technical details not described in detail in this embodiment, reference may be made to a defect detection device provided in any embodiment of the present application.

FIG. 10 is a flowchart of a defect detection method according to an embodiment of the present application. Referring to FIG. 10, a defect detection method provided in this embodiment includes:

Step 10. Generate a detection beam through the lighting module, and make the detection beam incident on the detection surface of the product to be tested; the illuminance of the detection beam and the half-width of the detection beam satisfy:

Step 20: It is detected by the imaging detection module whether the detection beam is scattered by the detection surface of the product to be tested to generate a scattered imaging beam, and if the scattered imaging beam is detected, the defect information is determined according to the scattered imaging beam.

Among them, S1 is the signal-to-noise ratio required to suppress crosstalk on the non-detection surface of the product under test, U1 is the central illuminance of the detection beam, R is the scattering efficiency of the smallest detectable defect within the receivable angle, and U2 is the detection The illuminance at the half-width edge of the beam, L is the scattering efficiency of the maximum crosstalk on the non-detection surface within the receivable angle, d is the thickness of the product to be measured; FOV is the effective field of view of the imaging detection module; α is The refraction angle of the detection beam in the product under test, β is the refraction angle of the scattered imaging beam in the product under test.

This embodiment uses the minimum detectable defect to scatter the light in the receivable angle, the maximum crosstalk on the non-detection surface to scatter the light in the receivable angle, and suppresses the non-detection surface of the product to be tested. The signal-to-noise ratio required for crosstalk to obtain the contrast between the half-width edge of the detection beam and the center of the detection beam; the refraction angle of the detection beam in the product under test, the refraction angle of the scattered imaging beam in the product under test, The thickness of the product to be tested and the effective field of view of the imaging detection module can be used to obtain the half-width of the detection beam required to suppress crosstalk on the non-detection surface of the product under test; Specific parameters. By setting a lighting module that meets the above parameters, the defect detection device in the embodiment of the present application can suppress crosstalk generated during the defect detection process and improve the accuracy of defect detection.

In an embodiment, determining the defect information according to the imaging light includes: determining a plurality of imaging signals according to the scattered imaging beams obtained multiple times in succession, and integrating the plurality of imaging signals to determine the defect information.

In one embodiment, in order to improve the quality of defect detection, the scattered imaging beam can be acquired multiple times in succession to obtain multiple imaging signals and integrate the multiple imaging signals, thereby improving the accuracy of the defect detection and the repeatability of the detection.

Claims

A defect detection device including an illumination module and an imaging detection module;

The illumination module is configured to generate a detection beam; the imaging detection module is configured to detect whether the detection beam is scattered by a detection surface of a product to be tested to generate a scattered imaging beam, and when the scattered imaging beam is detected, according to Determining the defect information of the product to be tested by the scattered imaging beam;

The illuminance of the detection beam satisfies:
Among them, S1 is the signal-to-noise ratio required to suppress crosstalk on the non-detection surface of the product under test, U1 is the central illuminance of the detection beam, and R is the scattering efficiency of light by the smallest detectable defect within the receivable angle. , U2 is the illuminance at the half-width edge of the detection beam, and L is the scattering efficiency of the maximum crosstalk on the non-detection surface to the light within a receivable angle;

The half-width W of the detection beam satisfies:

Where d is the thickness of the product to be measured; FOV is the effective field of view of the imaging detection module; α is the refraction angle of the detection beam in the product to be measured; β is the scattering imaging beam Describe the refraction angle in the product under test.
The defect detection device according to claim 1, wherein:

The illuminance of the detection beam also satisfies:
Among them, S2 is the signal-to-noise ratio required for suppressing the image crosstalk, M is the scattering efficiency of the detection beam in the image crosstalk direction in the image crosstalk area, and N is the scattered light of the detection beam in the image crosstalk direction. Describe the reflectivity in the product to be tested;

The half-width W of the detection beam also satisfies:
Wherein, θ is a refraction angle of the scattered light of the detection beam along the image crosstalk direction in the product to be measured.
The defect detection device according to claim 1, wherein an angular deviation of a main ray of the detection beam is less than 5 °;

The angular deviation of the main ray of the scattered imaging beam is less than 5 °.
The defect detection device according to claim 1, further comprising: a horizontal movement module;

The horizontal movement module is configured to carry the product to be tested to move in a direction parallel to the detection surface of the product to be tested.
The defect detection device according to claim 1, further comprising:

A focal plane measurement module and a vertical movement module connected to the focal plane measurement module;

The focal plane measurement module is configured to detect a defocus amount of a detection plane of the product to be measured;

The vertical movement module is configured to control the product to be measured to move in a direction perpendicular to the detection surface according to the defocus amount.
The defect detection device according to claim 1, wherein:

The imaging detection module is configured to determine the defect information of the product to be tested according to the scattered imaging beam by determining multiple imaging signals based on the scattered imaging beams acquired multiple times in succession, and performing Integrate to determine the defect information.
The defect detection device according to claim 6, wherein:

The imaging detection module includes an integration camera;

The integration camera is a time-delay integration TDI camera, a complementary metal oxide semiconductor CMOS camera, or a charge-coupled element CCD camera.
The defect detection device according to claim 7, wherein:

The imaging detection module further includes a light condensing unit, and the light condensing unit is configured to converge the scattered imaging light beam, so that the converged scattered imaging light beam enters the integrating camera.
The defect detection device according to claim 1, wherein:

The detection beam satisfies a Gaussian distribution.
A lithographic apparatus comprising the defect detection device according to any one of claims 1-9.
A defect detection method includes:

A detection beam is generated by the lighting module, and the detection beam is made incident on the detection surface of the product to be measured; the illuminance of the detection beam and the half width of the detection beam respectively satisfy:

Detecting whether the detection beam is scattered by the detection surface of the product to be tested by the imaging detection module to generate a scattered imaging beam, and determining the defect information according to the scattered imaging beam if the scattered imaging beam is detected;

Among them, S1 is the signal-to-noise ratio required to suppress crosstalk on the non-detection surface of the product under test, U1 is the central illuminance of the detection beam, and R is the scattering efficiency of light by the smallest detectable defect within the receivable angle. , U2 is the illuminance at the half-width edge of the detection beam, L is the scattering efficiency of the maximum crosstalk on the non-detecting surface within the receivable angle, and d is the thickness of the product under test; FOV is The effective field of view of the imaging detection module; α is the refraction angle of the detection beam in the product to be measured, and β is the refraction angle of the scattered imaging beam in the product to be measured.
The defect detection method according to claim 11, wherein determining defect information according to the scattered imaging beam comprises:

Determining a plurality of imaging signals according to the scattered imaging beams obtained multiple times in succession;

Integrating the plurality of imaging signals to determine the defect information.