CN115406905A - Defect detection device and correction method for defect detection - Google Patents

Defect detection device and correction method for defect detection Download PDF

Info

Publication number
CN115406905A
CN115406905A CN202110594591.XA CN202110594591A CN115406905A CN 115406905 A CN115406905 A CN 115406905A CN 202110594591 A CN202110594591 A CN 202110594591A CN 115406905 A CN115406905 A CN 115406905A
Authority
CN
China
Prior art keywords
light
light intensity
unit
defect
amplitude
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202110594591.XA
Other languages
Chinese (zh)
Inventor
张一志
张逸群
娄尚
杨晓青
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shanghai Micro Electronics Equipment Co Ltd
Original Assignee
Shanghai Micro Electronics Equipment Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shanghai Micro Electronics Equipment Co Ltd filed Critical Shanghai Micro Electronics Equipment Co Ltd
Priority to CN202110594591.XA priority Critical patent/CN115406905A/en
Publication of CN115406905A publication Critical patent/CN115406905A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01—Arrangements or apparatus for facilitating the optical investigation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
    • G01N21/958—Inspecting transparent materials or objects, e.g. windscreens
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
    • G01N21/956—Inspecting patterns on the surface of objects
    • G01N2021/95676—Masks, reticles, shadow masks

Abstract

The invention provides a defect detection device and a defect detection correction method, wherein the method comprises the following steps: the illumination unit provides telecentric illumination as measurement light. The measuring light generates scattered light after passing through the defect on the object to be measured, and the image detection unit acquires the light intensity of the scattered light and acquires defect information according to the light intensity. And controlling the storage unit to obtain and store the corresponding relation between the light intensity and the amplitude by using the light intensity of the scattered light and the real-time amplitude of the object to be detected, and compensating the light intensity by using the corresponding relation so as to correct the defect information. Therefore, the light intensity of the scattered light is associated with the real-time amplitude of the object to be detected, and the corresponding relation between the light intensity and the real-time amplitude is obtained, so that the light intensity is compensated according to the corresponding relation, the defect information is corrected, the influence of the vibration of the object to be detected on the defect detection precision caused by the internal motion mechanism and the external vibration is avoided, and the defect detection precision and the product yield are improved.

Description

Defect detection device and correction method for defect detection
Technical Field
The invention relates to the field of photoetching machines, in particular to a defect detection device and a defect detection correction method.
Background
In the manufacturing process of integrated circuits or flat panel displays, pollution control is a crucial link in order to improve the yield of products. Among them, the glass (glass) surface and the pellicle (pellicle) surface of the reticle, which is a pattern template, are susceptible to contamination, damage, and the like during clamping, transportation, storage, exposure, and the like, resulting in defects such as foreign particles, fingerprints, scratches, pinholes, and the like. If the defect detection is not performed before the exposure, the existence of the defects directly affects the exposure performance and the product yield of the lithography machine in the exposure process. Therefore, defect detection is required before exposure of the mask to determine whether the mask can be directly used for exposure, so as to avoid the influence of the defects of the mask on the exposure.
At present, a method for detecting defects of a mask is mainly implemented by using a defect detection device composed of a lighting unit and an image detection unit, specifically, measuring light is projected to the mask through the corresponding lighting unit, the measuring light is scattered at the defects of the mask, generated scattered light enters the corresponding image detection unit, and the image detection unit detects signals of the scattered light and processes detection results to obtain information such as equivalent sizes of the defects of the mask. Wherein, for guaranteeing the defect detection precision, the illumination unit need provide far away illumination, and far away degree is higher, detects more accurately.
However, the detection accuracy of the defect detection apparatus mainly composed of the illumination unit and the image detection unit at present cannot be further improved, and the main reasons include:
1. the defect detection device is generally integrated in a photoetching machine, and is limited by the mechanical space inside the photoetching machine, so that the conventional defect detection device is required to be small enough to avoid occupying too much mechanical space inside the photoetching machine, thereby causing the defect detection accuracy to be limited.
2. Because the upper surface and the lower surface of the mask plate need to be subjected to defect detection, the mask plate needs to be placed on a reticle in the actual detection process. However, since the plate fork is easily affected by the internal motion mechanism and the external vibration of the lithography apparatus, and the light intensity distribution gradient of the measuring light provided by the illumination unit is large, the defect detection result (e.g., the particle gray scale) of the defect detection apparatus has poor repeatability, which seriously affects the defect detection accuracy.
Therefore, a new defect detection apparatus and a correction method for defect detection are needed to improve the defect detection accuracy.
Disclosure of Invention
The invention aims to provide a defect detection device and a defect detection correction method, which aim to solve the problem of low defect detection precision.
In order to solve the above technical problem, the present invention provides a defect detection apparatus, including: the device comprises an illumination unit, an image detection unit, a focal plane measurement unit and a control storage unit;
the illumination unit is used for providing measuring light;
the image detection unit is used for acquiring the light intensity of scattered light which is scattered and generated after the measurement light passes through the defect on the object to be detected, and acquiring the defect information on the object to be detected according to the light intensity;
the focal plane measuring unit is used for measuring the real-time distance between the object to be measured and the image detecting unit and acquiring the real-time amplitude of the object to be measured according to the real-time distance;
the control storage unit is used for matching the light intensity of the scattered light acquired by the image detection unit with the real-time amplitude acquired by the focal plane measurement unit so as to acquire and store the corresponding relation between the light intensity and the amplitude, and compensating the light intensity of the scattered light detected by the image detection unit according to the corresponding relation so as to correct the defect information.
Optionally, in the defect detection apparatus, the control storage unit further includes an encoder, and the encoder is configured to mark a time variation to mark each time period as a corresponding code value interval.
Optionally, in the defect detection apparatus, the defect detection apparatus further includes a position adjusting unit, and the position adjusting unit is configured to adjust a position of the object to be detected.
Optionally, in the defect detecting apparatus, the position adjusting unit includes a first moving stage and a second moving stage;
the first motion table is used for adjusting the distance of the object to be measured in the first direction relative to the image detection unit according to the real-time distance obtained by the focal plane measurement unit;
the second motion platform is used for bearing the object to be measured and driving the object to be measured to move along a second direction so as to realize that the measuring light scans the whole surface of the object to be measured.
Optionally, in the defect detecting apparatus, the first direction and the second direction are perpendicular to each other.
Optionally, in the defect detection apparatus, the illumination unit includes a light emitter and a beam expander; the light emitter is used for providing illumination; the beam expander is used for expanding the illumination emitted by the light emitter, so that the diameter of the illumination is enlarged and the illumination can be propagated in parallel.
Optionally, in the defect detection apparatus, the illumination unit further includes a light adjustment mirror group, and the light adjustment mirror group is configured to adjust a divergence angle of the expanded light to a preset value.
Optionally, in the defect detection apparatus, the optical adjustment unit lens group includes a cylindrical micro lens array and/or a powell prism.
Optionally, in the defect detecting device, the illuminating unit further includes a collimator set, the collimator set is used for the warp the illumination of the light adjusting set expands the beam and forms the parallel the measuring light.
Optionally, in the defect detection apparatus, the image detection unit includes a detection mirror group and a detector; the detection mirror group is used for converging the scattered light and transmitting the scattered light to the detector; the detector is used for scanning and detecting the object to be detected.
Optionally, in the defect detection apparatus, the focal plane measurement unit includes a focusing sensor; the focusing sensor is used for measuring the real-time distance between the object to be measured and the image detection unit and acquiring the real-time amplitude of the object to be measured according to the real-time distance.
Based on the same inventive concept, the invention also provides a method for correcting defect detection, which comprises the following steps:
the illumination unit provides measurement light;
the measuring light is scattered through the defects on the object to be measured to generate scattered light, and the image detection unit acquires the light intensity of the scattered light and acquires defect information according to the light intensity;
the control storage unit matches the light intensity of the scattered light acquired by the image detection unit with the real-time amplitude of the object to be detected acquired by the focal plane measurement unit to acquire and store the corresponding relation between the light intensity and the amplitude, and compensates the light intensity of the scattered light detected by the image detection unit according to the corresponding relation to correct the defect information.
Optionally, in the defect detection correction method, the measurement frequency of the focal plane measurement unit is matched with the acquisition frequency of the image detection unit, so that the amplitude of the object to be detected is matched with the corresponding light intensity of the scattered light.
Optionally, in the defect detection and correction method, before the control storage unit matches the light intensity of the scattered light obtained by the image detection unit with the real-time amplitude of the object to be detected obtained by the focal plane measurement unit, a time variation is marked by using an encoder in the control storage unit, so as to mark each time period as a corresponding code value interval.
Optionally, in the method for correcting defect detection, the method for compensating the light intensity in the method for correcting defect detection includes:
averaging the real-time amplitudes within the code value interval to obtain an average amplitude;
subtracting the average amplitude from the real-time amplitude corresponding to each code value in the code value interval to obtain an amplitude relative value matrix;
converting the amplitude relative value matrix into a light intensity fluctuation proportionality coefficient matrix according to the corresponding relation between the light intensity and the amplitude;
and dividing the light intensity fluctuation proportionality coefficient matrix by the light intensity matrix formed by the light intensity corresponding to each code value in the code value interval to compensate the light intensity and obtain the compensated light intensity.
Optionally, in the method for correcting defect detection, after the compensated light intensity of the scattered light is obtained, the image detection unit obtains the corrected defect information according to the compensated light intensity of the scattered light.
In summary, the present invention provides a defect detection apparatus and a method for correcting defect detection, wherein the defect detection apparatus includes: the device comprises an illumination unit, an image detection unit, a focal plane measurement unit and a control storage unit. The illumination unit provides measurement light; the measuring light is scattered through defects on the object to be measured to generate scattered light, and the image detection unit acquires the light intensity of the scattered light and acquires defect information according to the light intensity. However, the internal motion and the external vibration of the defect detection device cause the vibration of the object to be detected, thereby affecting the detection accuracy. Therefore, the invention utilizes the control storage unit to match the light intensity of the scattered light acquired by the image detection unit with the real-time amplitude acquired by the focal plane measurement unit so as to acquire and store the corresponding relation between the light intensity and the amplitude. Then, the intensity of the scattered light detected by the image detection unit is compensated according to the corresponding relationship to correct the defect information. Therefore, the compensated light intensity can reduce the influence of the vibration of the object to be detected on the light intensity of the scattered light, so that the error of the defect information acquired by the image detection unit according to the scattered light is reduced, the defect information is corrected, and the defect detection precision and the product yield are improved.
Drawings
FIG. 1 is a schematic structural diagram of a defect detection apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a lighting unit of an embodiment of the present invention;
FIG. 3 is a schematic view of a plate fork according to an embodiment of the present invention;
FIG. 4 is a schematic illustration of the vibration of the plate fork of an embodiment of the present invention;
FIG. 5 is a simulation of a test for repeatability of grain measurement gray levels according to an embodiment of the present invention;
FIG. 6 is a flowchart of a method for correcting defect detection according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of the code value interval amplitude corresponding to the light intensity according to the embodiment of the present invention;
FIG. 8 is a graph of the measurement of pallet fork vibration and light intensity fluctuation in accordance with an embodiment of the present invention;
FIG. 9 is a schematic illustration of compensated light intensity fluctuations in accordance with an embodiment of the present invention;
fig. 10 is a test simulation of the repeatability of the compensated grain measurement gray scale of the embodiment of the invention.
Detailed Description
To further clarify the objects, advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is to be noted that the drawings are in simplified form and are not to scale, but are provided for the purpose of facilitating and clearly illustrating embodiments of the present invention. Further, the structures illustrated in the drawings are intended to be part of actual structures. In particular, the drawings are intended to show different emphasis, sometimes in different proportions. It should be further understood that the terms "first," "second," "third," and the like in the description are used for distinguishing between various components, elements, steps, and the like, and are not intended to imply a logical or sequential relationship between various components, elements, steps, or the like, unless otherwise indicated or indicated.
To solve the above technical problem, the present embodiment provides a defect detecting apparatus, referring to fig. 1, the defect detecting apparatus includes: an illumination unit 10, an image detection unit 20, a focal plane measurement unit 30, a position adjustment unit 40, and a control storage unit 50. The lighting unit 10 is used for measuring light. Optionally, the measurement light is telecentric illumination. The image detection unit 20 is configured to obtain light intensity of scattered light generated by scattering of the measurement light through a defect on the object M to be measured, and obtain defect information according to the light intensity. The focal plane measuring unit 30 is configured to measure a real-time distance between the object M to be measured and the image detecting unit 20, and obtain a real-time amplitude of the object M to be measured according to the real-time distance. The position adjusting unit 40 is configured to adjust a position of the object M. The control storage unit 50 is configured to match the light intensity of the scattered light obtained by the image detection unit 20 with the real-time amplitude obtained by the focal plane measurement unit 30, to obtain and store a corresponding relationship between the light intensity and the amplitude, and to compensate the light intensity of the scattered light detected by the image detection unit 20 according to the corresponding relationship, so as to correct the defect information.
Therefore, the defect detection device provided by this embodiment associates the light intensity of the scattered light with the real-time amplitude of the object to be detected, and obtains the corresponding relationship therebetween, thereby implementing compensation on the light intensity according to the corresponding relationship, further implementing correction on the defect information, avoiding the influence of the vibration of the object to be detected on the defect detection precision caused by the internal movement mechanism and the external vibration, and improving the defect detection precision and the product yield.
With continued reference to fig. 1, the control storage unit 50 includes an encoder 501. The encoder 501 is configured to mark the time variation to mark each time period as a corresponding code value interval. That is, one time point corresponds to one code value, and each code value interval corresponds to one time period. An engineer may select a code value interval according to test requirements, and in the code value interval, match the light intensity of the scattered light acquired by the image detection unit 20 with the real-time amplitude acquired by the focal plane measurement unit 30 to acquire a correspondence between the light intensity and the amplitude, and compensate the light intensity according to the correspondence to correct the defect information. Further, the encoder 501 may be disposed on the second motion stage 402.
The position adjustment unit 40 includes a first moving stage 401 and a second moving stage 402. The first moving stage 401 is configured to adjust a distance between the object M to be measured and the image detection unit 20 in a first direction (in this embodiment, the Z direction) according to the real-time distance obtained by the focal plane measurement unit 30. Typical measurement principles include, but are not limited to, multi-wavelength confocal measurements, triangulation, and the like. That is, the vertical height (height in the Z direction) of the object M to be measured is adjusted according to the real-time distance obtained by the focal plane measuring device 30, so as to ensure that the scattered light can enter the image detection unit 20, and when the measurement light is projected onto the surface of the object M to be measured without defects, the measurement light is reflected by the object M to be measured and generates reflected light, and the reflected light does not enter the image detection unit 20.
The second moving stage 402 is configured to bear the object M and drive the object M to move along a second direction (in this embodiment, a horizontal direction Y), so as to scan the entire surface of the object M with the measuring light. Wherein the first direction Z and the second direction Y are perpendicular to each other.
Further, the object M to be measured in this embodiment is exemplified by a mask. Referring now to fig. 2, a typical reticle has a length and width of about 152mm, and typically has an effective area of more than 132mm 104mm, which requires that the line spot generated by the illumination unit 10 be at least greater than 104mm, preferably greater than 125mm.
To ensure defect detection accuracy, the measurement light generated by the illumination unit 10 has the following characteristics: the deviation between the chief rays of the respective fields of view in the measuring beam is less than 5 degrees, preferably less than 1 degree. I.e. the measurement light provided by the illumination unit 10 needs to be telecentric illumination. The illumination field d of telecentric illumination, the focal length f of the collimating lens group and the divergence angle theta of the measuring light satisfy the following relation:
d＝f*sin(θ)*2；
however, since the mechanical space inside the lithography machine is very limited, the defect detection apparatus is required to be compact, i.e. the focal length f of the collimator group 104 is reduced as much as possible. On the premise of ensuring telecentric illumination, the divergence angle θ of the measurement light needs to be increased to meet the above requirements.
In this regard, the present embodiment provides a lighting unit 10. Referring to fig. 2, the illumination unit 10 includes a light emitter 101, a beam expander 102, a light adjusting lens set 103, and a collimating lens set 104 sequentially disposed along the light path. The light emitter 101 is, for example, a laser emitter, and is configured to provide linear illumination and transmit the linear illumination to the beam expander 102. The beam expander 102 is used for expanding the illumination, so that the diameter of the illumination is enlarged and can be propagated in parallel to the light adjusting lens group 103. The light adjusting mirror group 103 includes a cylindrical micro lens array and/or a powell prism, and is configured to adjust the divergence angle of the illumination to a preset value, and transmit the illumination to the collimating mirror group 104. The collimator set 104 is used for expanding the illumination and forming the parallel measuring light. The divergence angle of the illumination passing through the cylindrical micro lens array and/or the powell prism can be adjusted to be more than 20 degrees, so that the focal length of the collimating lens group 104 can be controlled to be less than 150mm, even less than 125mm. Therefore, the lighting unit 10 provided by the embodiment can meet the requirement of reducing the space occupied by the defect detection device, and has better adaptability and expansibility.
Further, the preset value range of the divergence angle is as follows: greater than 20 degrees and less than 90 degrees, preferably 25 degrees, 30 degrees, 35 degrees, or the like.
Referring to fig. 1, the image detection unit 20 includes a detection lens assembly 201 and a detector 202. When the surface of the object M to be measured has defects, the measuring light is scattered through the defects and generates scattered light. The detecting mirror group 201 is used for collecting the scattered light and transmitting the scattered light to the detector 202. When the surface of the object M to be measured has no defect, the image detection unit 20 does not receive the light beam, and the measuring light is reflected to the outside of the image detection unit 20 through the surface of the object M to be measured. The detector 202 is a detection camera, and is configured to continuously take a picture of the scattered light, and obtain the light intensity of the scattered light according to the picture, so as to obtain the defect information of the object to be detected. Wherein the defect information includes equivalent size information and position coordinate information of the defect.
Further, the focal plane measuring unit 30 includes a focusing sensor. The focusing sensor is configured to measure a real-time distance between the object M and the image detection unit 20, and calculate a real-time amplitude of the object M according to the real-time distance, that is, a vibration condition of the object M changing with time.
However, in actual inspection, the upper and lower surfaces of the object M to be inspected (in this embodiment, the reticle) need to be defect-inspected, so the reticle N shown in fig. 3 is required to support the reticle. The shape of the plate fork N is generally a square-shaped fork, so that the plate fork N is convenient to match with the shape of the mask. In order to bear the mask and meet the detection requirement, the thickness of the plate fork N is limited and cannot be thickened. Therefore, the mode of the plate fork N is low, and the plate fork is easily influenced by a motion mechanism inside equipment and external vibration, so that the vibration of the mask plate is caused, and the detection precision is influenced.
Referring to fig. 4, fig. 4 is a test chart of the plate fork N vibrating under the influence of the internal motion mechanism and the externally induced vibration when the mask plate is used for defect detection. It can be seen that the vibration of the plate fork N has a direct influence on the detection accuracy. Although the scattered light is homogenized by means of detector integration in the image detection unit 20 of the defect detection device, the influence of vibration on the detection accuracy cannot be reduced. In addition, due to the vibration of the reticle fork N, the incident angle of the measuring light and the receiving angle of the image detection unit 20 may deviate from the normal direction of the reticle, so that the influence of the vibration on the detection accuracy is amplified.
The repeatability of the particle measurement gray scale is a core index of defect detection, and when the particle size is required to be less than 30 micrometers, the repeatability of the particle measurement gray scale is required to be less than +/-3 micrometers. Then the measured vibration data of fig. 4 was simulated to find that the vibration had a repetitive effect on the measured particle gray level of up to 16.7%. Referring to fig. 5, at a particle size of 25 microns, due to large vibration, the repeatability of the measured gray level of the particles measured for multiple times can reach ± 8 microns at most, and the requirement of accurate detection cannot be met. It can be seen that vibration causes a large disturbance to defect detection.
It can be known through analysis that when vibration occurs, the corresponding residence time of the measured light distribution on the corresponding view field position changes, so that the obtained light intensity value has large fluctuation, and the corresponding repeatability is poor. In other words, due to vertical vibration, the speed of the plate fork N in the horizontal direction (Y direction) changes instantaneously, and in addition, the gradient of the light intensity distribution of the measuring light is large, part of the light intensity is high, and part of the light intensity is weak, so that if the horizontal speed is unstable, the obtained light intensity values in each field are difficult to be accurate. The following two cases are taken as examples, the first case being: at the position of the field of view with the highest relative light intensity, the horizontal instantaneous speed of the plate fork N is the slowest, the light intensity at the position of the field of view is acquired to be too high, and at the position of the field of view with the lowest relative light intensity, the horizontal instantaneous speed of the plate fork N is the fastest, and the value of the low light intensity may not be captured. Therefore, the light intensity at the field position finally obtained in the first case is higher. The second case is: the horizontal instantaneous speed of the pallet fork N is fastest at the position of the field of view where the relative light intensity is highest, and the value of the high light intensity may not be captured. And at the position of the view field with the lowest relative light intensity, the horizontal instantaneous speed of the plate fork N is the slowest, and the acquired light intensity at the position of the view field is too low. Therefore, the light intensity at the field position finally obtained in the second case is low.
Therefore, the vertical vibration of the plate fork N can cause the speed of the plate fork N in the horizontal direction Y to change instantaneously, fluctuation of scattered light is caused, repeatability of particle measurement gray scale is influenced, accuracy of obtaining light intensity information is further influenced, and the defect detection precision is reduced.
Therefore, the defect detection device provided by the embodiment can correct errors caused by vibration. In the defect detection apparatus provided in this embodiment, the control storage unit 50 can match the light intensity of the scattered light obtained by the image detection unit 20 with the real-time amplitude of the object M to be detected obtained by the focal plane measurement unit 30 in a set code value interval to obtain a corresponding relationship between the light intensity and the amplitude, compensate the light intensity according to the corresponding relationship, and further correct the defect information, so as to reduce the influence of vibration on the detection accuracy, which is described in detail in the following method for correcting defect detection.
Based on the same inventive concept, the present embodiment further provides a defect detection and correction method, referring to fig. 1 and 6, including:
step one S10: the illumination unit 10 provides measurement light. The warp cylinder microlens array and \ or powell prism among the light adjusting mirror group 103, and the cooperation under the effect of collimating mirror group 104, lighting unit 10 not only can provide telecentric illumination, can also satisfy and reduce the requirement in defect detection device shared space to make its adaptability and expansibility better.
Step two S20: the measuring light is scattered and generates scattered light after passing through the defect on the object to be measured M, and the image detection unit 20 acquires the light intensity of the scattered light and acquires defect information according to the light intensity.
Step three, S30: the time variation is marked by using the encoder 501 in the control storage unit 50 to mark each time period as a corresponding code value interval, the control storage unit 50 is then used to match the light intensity of the scattered light obtained by the image detection unit 20 with the real-time amplitude of the object M to be measured obtained by the focal plane measurement unit 30 in the selected code value interval to obtain the corresponding relationship between the light intensity and the amplitude, and the light intensity is compensated according to the corresponding relationship to correct the defect information.
First, linear fitting is performed on the code values of the encoder 501 to match the image acquisition frame number of the image detection unit 20 and the acquisition frequency of the focal plane measurement unit 30. Then, the fitted code value of the encoder 501 is substituted for the original code value, and then the set code value interval is intercepted.
Secondly, the measurement frequency of the focal plane measurement unit 30 is matched with the acquisition frequency of the image detection unit 20, so that the amplitude of the corresponding object M to be measured is matched with the light intensity of the corresponding scattered light at the same code value. Specifically, referring to fig. 7, in the present embodiment, a code value region [5185330, 8451997] is selected as an example. In the code value region [5185330, 8451997], the corresponding image 203 acquired by the image detection unit 20 is from frame 1 to frame 3500. After matching, the light intensity correspondence of the 1 st frame picture corresponds to a code value 5185330, the light intensity correspondence of the 3500 th frame picture corresponds to a code value 8451997, and other code values in the corresponding interval also correspond to corresponding pictures. Similarly, the focusing sensor also has corresponding readings in the code value region [5185330, 8451997], and the reading of the focusing sensor at the code value 5185330 corresponds to the light intensity of the picture of frame 1, and the reading at the code value 8451997 corresponds to the light intensity of the picture of frame 3500. In addition, other code values in the interval are matched with corresponding pictures and corresponding readings of the focusing sensor one by one.
The encoder 501 is in a hard trigger mode, and when the focusing sensor is read, the value of the encoder 501 is read at the same time, and the focusing sensor reading and the image acquisition frame are corresponding to each other through the value of the encoder 501. Then, as shown in fig. 8, normalization processing is performed on the obtained light intensity of the scattered light and the real-time amplitude of the object M to be measured, so as to obtain a corresponding relationship between the light intensity and the amplitude.
And after the corresponding relation between the light intensity and the amplitude is obtained, averaging the real-time amplitude in the code value interval to obtain the average amplitude. And subtracting the average amplitude from the real-time amplitude corresponding to each code value in the code value interval to obtain an amplitude relative value matrix. And finally, converting the amplitude relative value matrix into a light intensity fluctuation proportionality coefficient matrix according to the corresponding relation between the light intensity and the amplitude. And dividing the light intensity fluctuation proportionality coefficient matrix by the light intensity matrix formed by the light intensity corresponding to each code value in the code value interval to compensate the light intensity so as to obtain the compensated light intensity. After obtaining the compensated light intensity, the image detection unit 20 obtains the corrected defect information according to the compensated light intensity.
Fig. 9 is a schematic diagram of the compensated light intensity fluctuation, and fig. 10 is a test simulation diagram of the repeatability of the compensated particle measurement gray scale. Therefore, the repeatability of the compensated particle measurement gray scale is reduced from +/-8 micrometers to +/-2.1 micrometers, the detection requirement is met, and the defect detection precision is greatly improved.
In summary, the defect detection apparatus and the defect detection correction method provided in this embodiment utilize the control storage unit 50 to match the light intensity of the scattered light obtained by the image detection unit 20 with the real-time amplitude obtained by the focal plane measurement unit 30, so as to obtain and store the corresponding relationship between the light intensity and the amplitude. Then, the intensity of the scattered light detected by the image detection unit 20 is compensated according to the correspondence relationship to correct the defect information. Therefore, the compensated light intensity can reduce the influence of the vibration of the object to be detected on the light intensity of the scattered light, so that the error of the defect information acquired by the image detection unit 20 according to the scattered light is reduced, the defect information is corrected, and the defect detection precision and the product yield are improved. And, the warp cylinder microlens array and \ or powell prism among the light adjusting mirror group 103, and the cooperation under the effect of collimating mirror group 104, lighting unit 10 not only can provide telecentric illumination, can also satisfy and reduce the requirement in defect detection device shared space to make its adaptability and expansibility better.
It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. It will be apparent to those skilled in the art that many changes and modifications can be made, or equivalents employed, to the presently disclosed embodiments without departing from the intended scope of the invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention will still fall within the protection scope of the technical solution of the present invention.

Claims (16)

1. A defect detection apparatus, characterized in that the defect detection apparatus comprises: the device comprises an illumination unit, an image detection unit, a focal plane measurement unit and a control storage unit;
the illumination unit is used for providing measuring light;
the image detection unit is used for acquiring the light intensity of scattered light generated by scattering of the measuring light after the measuring light passes through the defect on the object to be detected, and acquiring defect information on the object to be detected according to the light intensity;
the focal plane measuring unit is used for measuring the real-time distance between the object to be measured and the image detecting unit and acquiring the real-time amplitude of the object to be measured according to the real-time distance;
the control storage unit is used for matching the light intensity of the scattered light acquired by the image detection unit with the real-time amplitude acquired by the focal plane measurement unit so as to acquire and store the corresponding relation between the light intensity and the amplitude, and compensating the light intensity of the scattered light detected by the image detection unit according to the corresponding relation so as to correct the defect information.
2. The apparatus of claim 1, wherein the control storage unit comprises an encoder configured to mark a time variation to mark each time period as a corresponding code value interval.
3. The apparatus of claim 1, further comprising a position adjustment unit for adjusting a position of the object to be inspected.
4. The defect detection apparatus of claim 3, wherein the position adjustment unit comprises a first motion stage and a second motion stage;
the first motion table is used for adjusting the distance of the object to be measured in the first direction relative to the image detection unit according to the real-time distance obtained by the focal plane measurement unit;
the second motion platform is used for bearing the object to be measured and driving the object to be measured to move along a second direction so as to realize that the measuring light scans the whole surface of the object to be measured.
5. The defect detection apparatus of claim 4, wherein the first direction and the second direction are perpendicular to each other.
6. The defect detection apparatus of claim 1, wherein the illumination unit comprises a light emitter and a beam expander; the light emitter is used for providing illumination; the beam expander is used for expanding the illumination emitted by the light emitter, so that the diameter of the illumination is enlarged and the illumination can be propagated in parallel.
7. The apparatus of claim 6, wherein the illumination unit further comprises a set of light adjusting mirrors for adjusting the divergence angle of the expanded illumination to a predetermined value.
8. The apparatus of claim 7, wherein the set of light adjustment units comprises a cylindrical micro lens array and/or a Powell prism.
9. The defect detection device of claim 7, wherein the illumination unit further comprises a set of collimators for expanding the illumination passing through the set of light modifiers and forming the parallel measurement light.
10. The defect detection apparatus of claim 1, wherein the image detection unit comprises a detection mirror group and a detector; the detection mirror group is used for converging the scattered light and transmitting the scattered light to the detector; the detector is used for scanning and detecting the object to be detected.
11. The defect detection apparatus of claim 1, wherein the focal plane measurement unit comprises a focusing sensor; the focusing sensor is used for measuring the real-time distance between the object to be measured and the image detection unit and acquiring the real-time amplitude of the object to be measured according to the real-time distance.
12. A method of correcting defect detection using the defect detection apparatus according to any one of claims 1 to 11, the method comprising:
the illumination unit provides measurement light;
the measuring light is scattered after passing through the defect on the object to be measured and generates scattered light, and the image detection unit acquires the light intensity of the scattered light and acquires defect information according to the light intensity;
the control storage unit matches the light intensity of the scattered light acquired by the image detection unit with the real-time amplitude of the object to be detected acquired by the focal plane measurement unit to acquire and store the corresponding relation between the light intensity and the amplitude, and compensates the light intensity of the scattered light detected by the image detection unit according to the corresponding relation to correct the defect information.
13. The method of claim 12, wherein the measurement frequency of the focal plane measurement unit is matched to the acquisition frequency of the image detection unit, so that the amplitude of the object to be measured is matched to the corresponding intensity of the scattered light.
14. The method of claim 12, wherein before the control storage unit matches the intensity of the scattered light obtained by the image detection unit with the real-time amplitude of the object to be measured obtained by the focal plane measurement unit, a time variation is marked by an encoder in the control storage unit to mark each time period as a corresponding code value interval.
15. The method of claim 14, wherein the method of compensating for the light intensity in the method of correcting for defect detection comprises:
averaging the real-time amplitudes within the code value interval to obtain an average amplitude;
subtracting the average amplitude from the real-time amplitude corresponding to each code value in the code value interval to obtain an amplitude relative value matrix;
converting the amplitude relative value matrix into a light intensity fluctuation proportionality coefficient matrix according to the corresponding relation between the light intensity and the amplitude;
and point-dividing a light intensity fluctuation proportionality coefficient matrix by a light intensity matrix formed by the light intensity corresponding to each code value in the code value interval so as to compensate the light intensity and obtain the compensated light intensity.
16. The method of claim 15, wherein after obtaining the compensated intensity of the scattered light, the image detection unit obtains the corrected defect information according to the compensated intensity of the scattered light.
CN202110594591.XA 2021-05-28 2021-05-28 Defect detection device and correction method for defect detection Pending CN115406905A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110594591.XA CN115406905A (en) 2021-05-28 2021-05-28 Defect detection device and correction method for defect detection

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110594591.XA CN115406905A (en) 2021-05-28 2021-05-28 Defect detection device and correction method for defect detection

Publications (1)

Publication Number Publication Date
CN115406905A true CN115406905A (en) 2022-11-29

Family

ID=84155798

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110594591.XA Pending CN115406905A (en) 2021-05-28 2021-05-28 Defect detection device and correction method for defect detection

Country Status (1)

Country Link
CN (1) CN115406905A (en)

Similar Documents

Publication Publication Date Title
US5694214A (en) Surface inspection method and apparatus
KR101735403B1 (en) Inspection method, templet substrate and focus offset method
CN102818528B (en) Apparatus and method for inspecting an object with increased depth of field
KR100291258B1 (en) Compact reticle inspection system for inspecting reticles with high accuracy, and how to inspect reticles
KR101782336B1 (en) Inspection apparatus and inspection method
KR101547649B1 (en) Inspection apparatus
JPH03267745A (en) Surface property detecting method
US9557277B2 (en) Inspection apparatus and inspection method
US20020001403A1 (en) Focusing control mechanism, and inspection apparatus using same
US5337140A (en) Optical detecting system wtih self-correction
JP4486320B2 (en) Sensor alignment method in three-dimensional measurement system
US7548321B2 (en) Method for enhancing the measuring accuracy when determining the coordinates of structures on a substrate
CN115406905A (en) Defect detection device and correction method for defect detection
CN111398295B (en) Defect detection device and method thereof
CN111220621B (en) Chip inclined surface detection method
CN114509923A (en) Focusing and leveling device in design of deep ultraviolet objective lens and application thereof
JPH0534128A (en) Detecting apparatus of extraneous substance
JP5033365B2 (en) Inspection device
CN115406894A (en) Illumination device, defect detection system, photoetching machine and defect detection method
CN101074866A (en) Method for reinforcing measurement precision of substrate structure coordinate
JP3202322B2 (en) Mask inspection equipment
KR0149007B1 (en) Lens assembling apparatus
CN116661166A (en) Parallelism adjusting device and optical detection equipment
JPH01292206A (en) Surface condition measuring apparatus for object
JP2534699B2 (en) Optical axis direction position correction method in mask / reticle processing apparatus

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination