JP2019128271A - Inspection device - Google Patents

Abstract

To provide an inspection device that can detect a correct amount of position deviation from a reference image of a pattern on an inspected sample.SOLUTION: An inspection device comprises: an illumination unit 400 that emits first illumination light; a branch unit 910 that branches the first illumination light into second and third illumination light; a reference member 930 that has a reference pattern for position deviation purposes; a detection unit 800 that detects the second and third illumination light; an image formation unit 500 that acquires an optical image of an inspected sample, using the second illumination light, and acquires a reference-purpose pattern image, using the third illumination light; a reference image creation unit 620 that creates a reference image on the basis of pattern data; a comparison unit 610 that compares the optical image with the reference image; a first position deviation-amount acquisition unit 692 that acquires a first amount of position deviation, using the reference-purpose pattern image; a second position deviation-amount acquisition unit 696 that measures a deviation from a reference position of the optical image, and acquires a second amount of position deviation on the basis of the measured deviation; and a position deviation-amount correction unit 698 that obtains a third amount of position deviation on the basis of a comparison result of the comparison unit 610, the first amount of position deviation, and the second amount of position deviation, and makes a correction on the basis of the obtained third amount of position deviation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inspection apparatus. For example, the present invention relates to an inspection apparatus which irradiates a laser beam to a sample to be inspected such as a mask used for manufacturing a semiconductor element or the like, acquires an optical image of a pattern image, and inspects the pattern.

  In recent years, there has been an increasing demand for accuracy management of circuit line widths required for semiconductor elements. These semiconductor elements use an original pattern pattern (also referred to as a photolithography mask or reticle; hereinafter collectively referred to as a mask) on which a circuit pattern is formed, and the pattern is exposed and transferred onto a wafer by a reduction projection exposure apparatus called a stepper. It is manufactured by circuit formation. Therefore, a pattern drawing apparatus using an electron beam capable of drawing a fine circuit pattern is used for manufacturing a mask for transferring such a fine circuit pattern onto a wafer. Pattern circuits may be drawn directly on a wafer using such a pattern drawing apparatus.

  For the manufacture of LSIs such as CPU (Central Processing Unit) and FPGA (Field Programmable Gate Array), which require significant manufacturing costs, improvement in yield is indispensable. One of the major factors that reduce the yield is a pattern defect of a mask used when an ultrafine pattern is exposed and transferred onto a semiconductor wafer by a photolithography technique. In recent years, along with the miniaturization of the dimensions of LSI patterns formed on semiconductor wafers, the dimensions that must be detected as pattern defects have become extremely small. Therefore, it is considered desirable to increase the accuracy of a pattern inspection apparatus for inspecting a defect of a transfer mask used in LSI manufacturing.

  As an inspection method, an optical image obtained by imaging at a predetermined magnification a pattern formed on a sample such as a photolithography mask using a magnifying optical system, design pattern data, or an optical image obtained by imaging the same pattern on the sample It is known how to test by comparing with. For example, as a pattern inspection method, “die to die (die-to-die) inspection” in which optical image data obtained by imaging the same pattern at different places on the same mask are compared, The drawing data (pattern data) converted to the device input format for drawing by the drawing device at the time of drawing is input to the inspection device, design image data (reference image) is generated based on this, and the pattern is imaged There is a “die to database (die-database) inspection” that compares an optical image as measured data. In the inspection method in such an inspection apparatus, the sample is placed on the stage, and the stage moves, so that the light beam scans on the sample and the inspection is performed. The sample is irradiated with a light beam by a light source and an illumination optical system. The light transmitted or reflected through the sample is imaged on the photodetector through the optical system. The image picked up by the photodetector is sent to the comparison circuit as measurement data. The comparison circuit compares the measurement data and the reference data according to an appropriate algorithm after alignment of the images, and determines that there is a pattern defect if they do not match.

  Patent Document 1 discloses a pattern inspection apparatus that compares an optical image of an inspection sample on which a pattern is formed with a reference image in which the amount of positional deviation is corrected.

JP 2012-002674 A

  The problem to be solved by the present invention is to provide an inspection apparatus capable of acquiring an accurate displacement amount of a pattern on a sample to be inspected from a reference image.

  An inspection apparatus according to one embodiment of the present invention includes an illumination unit including a light source that emits first illumination light, a branching unit that branches the first illumination light into second illumination light and third illumination light, and a position. An optical image of the pattern of the sample to be inspected using the reference member having the reference pattern for measuring the deviation, the detection unit for detecting the second illumination light and the third illumination light, and the second illumination light. An imaging unit that acquires and acquires a reference pattern image of the reference pattern using the third illumination light, a reference image generation unit that generates a reference image based on pattern data that is a basis of the pattern, and an optical image A comparison unit that compares the reference image with the reference image, a first misregistration amount acquisition unit that acquires the first misregistration amount using the reference pattern image, and measures the deviation of the optical image from the reference position Second displacement amount for acquiring a second displacement amount based on the generated deviation The third positional deviation amount is obtained based on the comparison result of the obtaining unit, the comparison unit, the first positional deviation amount, and the second positional deviation amount, and the correction is performed based on the obtained third positional deviation amount. And a positional deviation correction unit that

  In the inspection apparatus according to the above aspect, the reference member is preferably a reflector.

  According to one aspect of the present invention, it is possible to provide an inspection apparatus that can acquire an accurate positional deviation amount of a pattern on a sample to be inspected from a reference image.

It is a schematic diagram of the inspection apparatus of embodiment. It is a schematic diagram of the to-be-tested sample (mask) test | inspected with the inspection apparatus of embodiment. It is a flowchart of the inspection method of embodiment. It is a schematic diagram which shows the relationship between an optical system visual field and 1st positional displacement amount. It is a schematic diagram which shows the shift | offset | difference of the acquired optical image and reference image based on deviation (angle (theta)). It is a schematic diagram which shows the correction method of the 2nd position shift amount based on deviation (angle (theta)). It is a schematic diagram which shows the correction method of the 1st position shift amount.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the following description, a photolithography mask (sample to be inspected) is simply referred to as a mask.

  The inspection apparatus according to the embodiment measures an illuminating unit having a light source that emits first illumination light, a branching unit that divides the first illumination light into second illumination light and third illumination light, and misalignment. An optical image of the pattern of the sample to be inspected using the reference member having a reference pattern for detecting, a detection unit for detecting the second illumination light and the third illumination light, and the second illumination light, An imaging unit that acquires a reference pattern image of a reference pattern using the third illumination light, a reference image generation unit that generates a reference image based on pattern data that is a basis of the pattern, an optical image, and a reference image The deviation from the reference position of the optical image and measuring the deviation from the reference position of the optical image. Second positional deviation amount acquisition unit for acquiring a second positional deviation amount based on A position at which correction based on the third displacement amount obtained is obtained by obtaining a third displacement amount based on the comparison result of the comparison unit, the first displacement amount, and the second displacement amount. And a shift amount correction unit.

  FIG. 1 is a schematic diagram of an inspection apparatus 1000 according to the present embodiment. The inspection apparatus of the present embodiment is a pattern inspection apparatus that performs defect inspection of the mask M.

  The mask M is placed on the holding unit 100.

  The stage 200 is disposed below the holding unit 100 and supports the holding unit 100. The stage 200 is moved by the first stage control unit 210a and the second stage control unit 210b in the X direction and the Y direction which are lateral directions orthogonal to each other. The stage 200 is moved by the third stage controller 210c in the Z direction, which is a direction perpendicular to the X direction and the Y direction. Furthermore, the stage 200 is rotated by the fourth stage control unit 210d in a plane perpendicular to the Z direction. The first stage control unit 210a, the second stage control unit 210b, the third stage control unit 210c, and the fourth stage control unit 210d are, for example, known motors or piezo elements.

  The laser length meter 220 measures the position of the stage 200 in the X direction, the position in the Y direction, the position in the Z direction, and the amount of rotation in a plane perpendicular to the Z direction. The measured position of the stage 200 is input to a position detection unit 640 described later.

  The movement control mechanism 300 is configured such that the stage 200 is moved within the scanning range set by the scanning range setting mechanism 310 connected to the control computer 650 to be described later via the bus line 670 and the scanning range setting mechanism 310. And a stage control mechanism 320 for controlling the first stage control unit 210a, the second stage control unit 210b, the third stage control unit 210c, and the fourth stage control unit 210d.

  The illumination unit 400 includes an aperture stop 408, a light source 410, a first illumination unit lens 420, a second illumination unit lens 430, a first illumination unit mirror 440, a condenser lens 450, 1 illumination part light beam distribution means 460, second illumination part mirror 470, and second illumination part light beam distribution means 480.

  The imaging unit 500 includes a first light detector 510 and a second light detector 520. The second photodetector 520 includes a first photodetector unit 520a and a second photodetector unit 520b.

  The detection unit 800 includes an objective lens 810, a detection unit light beam distribution unit 820, a first detection unit lens 830, and a second detection unit lens 840.

  In addition, the inspection apparatus 1000 includes a branching unit 910, a first positional deviation amount measuring unit mirror 920, and a reference member 930.

  The reference member 930 has a reference pattern for measuring misalignment. Here, the reference pattern is, for example, a predetermined line and space pattern, but is not limited thereto.

  The reference member 930 is, for example, a reflector. However, the third illumination light may be transmitted through the reference member 930 by using the reference member 930 as a transmission plate.

  The first illumination light such as laser light emitted from the light source 410 passes through the aperture stop 408 and is expanded to a parallel light flux by the first illumination unit lens 420 and the second illumination unit lens 430. Ru. The aperture stop 408 adjusts the thickness of the light flux, that is, the numerical aperture (NA).

  The first illumination light whose diameter has been expanded into a parallel light beam is reflected by the first illumination unit light beam distribution unit 460, and then the second illumination unit mirror 470 and the second illumination unit beam distribution unit 480. The lower surface of the mask M is irradiated by this. The first illumination part light beam distribution means 460, the second illumination part mirror 470, and the second illumination part light beam distribution means 480 constitute a reflective illumination system.

  In addition, the first illumination light whose diameter has been expanded to a parallel light flux passes through the first light flux distribution means 460 for the illumination unit, and then is branched into the second illumination light and the third illumination light by the branching unit 910. Ru.

  The second illumination light is irradiated on the upper surface of the mask M by the first illumination unit mirror 440 and the condenser lens 450. The first illumination unit lens 420, the second illumination unit lens 430, the first illumination unit mirror 440, and the condenser lens 450 constitute a transmission illumination system.

  The second illumination light irradiated on the upper surface of the mask M by the transmission illumination system and transmitted through the mask M is called transmitted light. The first illumination light reflected by the mask M after being irradiated on the lower surface of the mask M by the reflective illumination system is called reflected light. The transmitted light and the reflected light pass through the objective lens 810 and the second luminous flux distribution means 480 for the illumination section, and then enter the detection luminous flux distribution means 820. The transmitted light is imaged on the first light detection unit 520a of the second photodetector 520 from the detection unit light beam distribution means 820 through the second detection unit lens 840. In addition, the reflected light is imaged on the first light detector 510 through the detection light flux distribution unit 820 through the first detection lens 830. Note that after the second illumination light is irradiated to the lower surface of the mask M by the reflective illumination system, the second illumination light may be reflected by the mask M.

  The third illumination light is reflected by the first misalignment amount measurement unit mirror 920 and the reference member 930 and passes through the second detection unit lens 840 from the detection unit light beam distribution unit 820 to perform the second light detection. The image is formed on the second light detection unit 520b of the detector 520.

  Since the wavelength of the light source 410 can inspect the mask M in a state close to that when exposure is performed using the mask M, the wavelength of the light source 410 is approximately the same as the wavelength of the light source included in the exposure apparatus in which the mask M is used. Is desirable.

  The autofocus mechanism 700 includes an autofocus beam distribution unit 710, a focus shift detection unit 720, a focus control unit 730, and an autofocus unit motor 740.

  The autofocus light beam distribution means 710 causes the reflected light to be incident on the focus shift detection unit 720. The focus shift detection unit 720 detects the degree of focus shift from the incident reflected light, and inputs the degree of focus shift to the focus control unit 730. The focus control unit 730 controls the autofocus unit motor 740 based on the input degree of focus shift to move the objective lens 810 in the height direction, and adjusts the focus of the objective lens 810 on the mask M. The objective lens 810 may be focused on the mask M by moving the stage in the Z direction using the third stage control unit 210c.

  Specifically, a half mirror, a slit, a polarization beam splitter, or the like can be preferably used as the light beam distribution unit and the branching unit 910.

  The control unit 600 includes a comparison unit 610, a reference image generation unit 620, a development unit 622, a pattern data storage unit 630, an image storage unit 636, a position detection unit 640, a control computer 650, and a determination unit 660. A bus line 670, a review unit 680, a map creation unit 690, a first displacement amount acquisition unit 692, a second displacement amount acquisition unit 696, and a displacement amount correction unit 698.

  FIG. 2 is a schematic view of a sample (mask) to be inspected by the inspection apparatus of the embodiment. FIG. 2A is a schematic view of the mask M to be inspected in the embodiment.

  The mask M has an inspection area I provided on the substrate S. The substrate S is made of, for example, quartz. In the inspection area I, patterns such as a line and space pattern B and a solid pattern C are arranged. The "solid pattern" refers to a portion where the pattern does not enter inside the optical system field of view E during scanning.

  As an inspection method of the mask M, for example, the stage 200 is driven in the Y-axis direction, and the inspection region I is passed through the optical system visual field E, whereby the first photodetector 510 or the second photodetector. A strip-shaped area image F of the sensor width of the first light detection unit 520a or 520 is acquired. Next, the stage 200 is moved in the X-axis direction at a predetermined pitch. Next, the stage 200 is driven in the Y-axis direction to acquire an area image of another portion of the inspection area I. This is repeated to acquire area images of all inspection areas I.

  FIG. 2B is a schematic view showing the inspection method of the area image F. As shown in FIG. The acquired area image F is divided into a plurality of processing blocks G by the comparison unit 610. Then, for each processing block G, a comparison to be described later is performed.

  Note that the inspection method of the mask M is not limited to the above description.

  FIG. 3 is a flowchart of the inspection method of the embodiment.

  First, test preparation is performed (S10). The mask M is placed on the stage 200.

  Next, the design pattern data stored in the pattern data storage unit 630 is input to the expansion unit 622 and expanded for each layer. Design pattern data is created in advance by a designer. Here, the design pattern data is not usually designed to be read directly by the inspection apparatus 1000. Therefore, the design pattern data is first converted into intermediate data created for each layer, then converted into data of a format that can be read directly by each inspection apparatus 1000, and then input to the expansion unit 622.

  Next, using the reference image generation unit 620, a reference image serving as a reference for the optical image is created from the pattern data that is developed for each layer by the development unit 622 and is the basis of the pattern of the mask M. The generated reference image is input to the comparison unit 610.

  Next, using the light source 410 of the illumination unit 400, the first illumination light is emitted. The emitted first illumination light is branched into a second illumination light and a third illumination light at a branching unit 910.

  Next, the imaging unit 500 acquires a reference pattern image of the reference pattern using the third illumination light (S12).

  Next, the comparison unit 610 compares the reference pattern image with the reference pattern reference image which is the reference of the reference pattern. Here, as an example of comparison, there is a method of comparing the light amount of the portion of the pattern of the reference pattern image with the light amount of the portion of the pattern of the corresponding reference pattern reference image.

  Next, the first misregistration amount acquisition unit 692 acquires the first misregistration amount by using a comparison between the reference pattern image and the reference pattern reference image (S14).

  The reference pattern reference image may be created, for example, using the reference image generation unit 620, or may be stored in the image storage unit 636.

  FIG. 4 is a schematic diagram showing the relationship between the optical system field of view and the first positional deviation amount.

  The optical system field of view fluctuates due to the temperature change in the detection unit 800 and the fluctuation of air. The amount of pattern displacement obtained by this fluctuation is the first displacement amount. FIG. 4A is a schematic view showing the positional relationship between the optical system field of view and the second light detection unit 520b when there is no first positional deviation amount. FIG. 4B is a schematic diagram of a reference pattern image of the reference member 930 when there is no first positional deviation amount. When there is no first positional deviation amount, the reference pattern image is acquired without deviation.

  FIG. 4C is a schematic view showing the positional relationship between the optical system field of view and the second light detection unit 520b when there is a first positional deviation amount. In the case of FIG. 4C, the field of view of the optical system is shifted to the left on the paper surface because of the first displacement amount. FIG. 4D is a schematic view of a reference pattern image of the reference member 930 in the case of FIG. 4C. Since the optical system field of view is shifted to the left side on the paper surface, the acquired reference pattern image is also shifted to the left side on the paper surface.

  FIG. 4E is a schematic diagram showing the positional relationship between the optical system field of view and the second light detection unit 520b when the optical system field of view is shifted to the right side of the drawing due to the first positional shift amount. FIG. 4 (f) is a schematic view of a reference pattern image of the reference member 930 in the case of FIG. 4 (e). Since the optical system field of view is shifted to the right side on the paper surface, the acquired reference pattern image is also shifted to the right side on the paper surface.

  In addition, the imaging unit 500 acquires an optical image of the pattern of the mask M using the second illumination light (S22). The acquired optical image is stored in the image storage unit 636. The acquired optical image is input to the comparison unit 610.

  Here, acquisition of the reference pattern image of the reference pattern using the third illumination light (S12) and acquisition of the optical image of the pattern of the mask M using the second illumination light (S22) are performed simultaneously. Is preferred. It is considered that the fluctuation of the optical system visual field due to the temperature change in the detection unit 800 and the fluctuation of the air is particularly large between the second photodetector 520 and the second luminous flux distribution means 480. Therefore, when obtaining a third positional shift amount to be described later, acquisition of a reference pattern image of the reference pattern using the third illumination light and acquisition of an optical image of the pattern of the mask M using the second illumination light. Are simultaneously performed, the amount of misalignment associated with the fluctuation of the optical field of view acquired with the reference pattern image of the reference pattern is equivalent to the amount of misalignment associated with the fluctuation of the optical field of view acquired with the pattern of the mask M. Be For this reason, it is possible to accurately replace the positional shift amount accompanying the fluctuation of the optical field of view acquired with the pattern of the mask M with the first positional shift amount acquired with the reference pattern image of the reference pattern.

  Next, the comparison unit 610 compares the optical image and the reference image (S24). Here, as an example of the comparison, there is a method of comparing the light amount at the location of the pattern of the optical image and the light amount at the location of the pattern of the corresponding reference image.

  Next, the second positional deviation amount acquisition unit 696 measures the deviation of the optical image from the reference position based on the comparison of the optical image and the reference image (S26). Next, the second positional deviation amount acquisition unit 696 acquires a second positional deviation amount based on the deviation (angle θ) (S28).

  FIG. 5 is a schematic view showing a shift between an acquired optical image and a reference image based on a deviation (angle θ). FIG. 5A is a schematic diagram illustrating a deviation between an acquired optical image and a reference image. FIG. 5B is a schematic diagram illustrating the shift between the optical image and the reference image in a graph. In FIG. 5B, for example, the dotted line is a positional deviation amount obtained by the comparison result of the comparison unit 610 in each inspection region, and the solid line is a straight line that approximates the positional deviation amount.

  The mask M may be mounted at an angle θ with respect to the x direction which is the scanning direction of the stage 200. In this case, the acquired pattern has a positional shift due to the angle θ with respect to the reference image. The amount of positional deviation resulting from this positional deviation is a second amount of positional deviation. In order to obtain an accurate misregistration amount from the reference image, it is preferable to remove the second misregistration amount.

  In FIG. 5A, the positional deviation Δx in the x direction of the point A ′ of the optical image from the point A of the reference image is Δx = 1−cos θ. Further, the positional deviation Δy in the y direction is Δy = sin θ. If the deviation (angle θ) is small, then Δx is zero and Δy is approximated by θ. Therefore, in this case, as shown in FIG. 5B, the second misregistration amount can be represented by an approximate straight line by a first term of the deviation (angle θ).

  Next, the misregistration amount correction unit 698 obtains a third misregistration amount based on the comparison result between the optical image and the reference image by the comparison unit 610, the first misregistration amount, and the second misregistration amount. (S30) A correction based on the third positional deviation amount is performed (S32).

  FIG. 6 is a schematic view showing a method of correcting the second positional deviation amount based on the deviation (angle θ). As described above, when the deviation (angle θ) is small, the deviation (angle θ) is obtained by subtracting the approximate straight line based on the first term of the deviation (angle θ) from the amount of positional deviation obtained from the comparison result of the comparison unit 610. The second positional deviation amount based on θ) can be corrected satisfactorily. Note that the second misalignment correction method is not limited to this.

  FIG. 7 is a schematic view showing a method of correcting the first positional deviation amount. For example, the first positional deviation amount and the second positional deviation amount are corrected by subtracting the first positional deviation amount, for example, from the positional deviation amount in which the second positional deviation amount has been corrected, as shown in FIG. The third positional deviation amount can be obtained.

  The map creation unit 690 may be used to create a mask pattern displacement distribution map (abbreviated as “Registration map” or “Reg map”) based on the third displacement amount.

  Next, the effects of the inspection apparatus of the embodiment will be described.

  When the optical image and the reference image are compared to obtain a difference, an operation of aligning the position of the optical image and the reference image is performed. This work is performed on the entire surface of the inspection area. The distribution of the positional deviation of the pattern on the optical image with respect to the pattern on the reference image acquired at this time is acquired as a map of the positional deviation distribution of the mask pattern.

  One of the causes of an error in the map of the displacement distribution of the mask pattern is fluctuation of the optical system field of view in the detection unit 800. In order to detect this fluctuation, the inspection apparatus 1000 of the present embodiment divides the first illumination light into the second illumination light and the third illumination light, and a reference member 930 having a reference pattern. And. The imaging unit 500 includes an optical image of the pattern of the mask M using the second illumination light and a reference pattern image of the reference pattern using the third illumination light.

  The second illumination light and the third illumination light pass through the detection unit 800. Therefore, by continuously detecting, for example, the edge position of the line-and-space pattern in the reference pattern image, it is possible to detect the first positional deviation amount caused by the optical system visual field fluctuation in the detection unit 800.

  In addition, the second illumination light used to acquire the optical image and the third illumination light used to acquire the reference pattern image both diverge from the first illumination light emitted from the same light source 410. It is branched by the part 910. Therefore, it is possible to remove the influence of the fluctuation that the first illumination light itself has.

  Furthermore, it is difficult to place the mask M completely parallel to the scanning direction of the stage 200. When the mask M is placed by being inclined by the deviation (angle θ), the acquired optical image is inclined by the deviation (angle θ) with respect to the reference image. On the other hand, with respect to the first displacement amount detected from the reference pattern, the influence of the deviation (angle θ) can be removed by accurately placing the reference member 930 and the like. Therefore, it is preferable to remove the influence of the deviation (angle θ) resulting from the placement of the mask M when creating a map of the positional deviation distribution of the mask pattern.

  The inspection apparatus 1000 according to the present embodiment includes a second positional deviation amount acquisition unit 696 that measures a deviation of the optical image from the reference position and acquires a second positional deviation amount based on the measured deviation. Thereby, the influence of the deviation (angle θ) resulting from the placement of the mask M can be removed.

  Furthermore, in the inspection apparatus 1000 of the present embodiment, the third positional deviation amount is calculated based on the comparison result of the comparing unit 610, the first positional deviation amount, and the second positional deviation amount. And a displacement amount correction unit 698 that performs correction based on the displacement amount of the image. As a result, a third positional deviation amount obtained by correcting the first positional deviation amount caused by the fluctuation of the optical system and the second positional deviation amount caused by the deviation (angle θ) caused by placing the mask M is obtained. And optical image correction can be performed.

  According to the inspection apparatus of the embodiment, it is possible to provide an inspection apparatus capable of detecting an accurate positional deviation amount from a reference image of a pattern on a sample to be inspected.

  The embodiments of the present invention have been described above with reference to specific examples. The above embodiments are only given as examples, and do not limit the present invention. Further, the components of each embodiment may be combined as appropriate.

  For example, in the above description, it is assumed that the second light detector 520 is used to detect the transmitted light of the second illumination light and the third illumination light. However, the first light detector 510 may be used to detect the second illumination light, the reflected light, and the third illumination light.

  In the embodiment, the description is omitted for the device configuration, the manufacturing method, and the parts that are not directly required for the description of the present invention, but the required device configuration, the manufacturing method, and the like can be appropriately selected and used. In addition, all inspection apparatuses that include the elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention. The scope of the present invention is defined by the appended claims and equivalents thereof.

100 holding unit 200 stage 210a first stage control unit 210b second stage control unit 210c third stage control unit 210d fourth stage control unit 220 laser length measuring device 300 movement control mechanism 310 scanning range setting mechanism 320 stage control mechanism 400 illumination unit 408 aperture stop 410 light source 420 lens for the first illumination unit 430 lens for the second illumination unit 440 first illumination unit mirror 450 condenser lens 460 first illumination beam distribution means 470 second illumination Part mirror 480 Second illumination part light flux distribution means 500 Imaging part 510 First light detector 520 Second light detector 520 a First light detection part 520 b Second light detection part 600 Control part 610 Comparison Unit 620 Reference image generation unit 622 Development unit 630 Pattern data storage unit 636 Image storage unit 640 Position detection unit 650 Control computer 660 Determination unit 670 Bus line 680 Review unit 690 Map creation unit 692 First displacement amount acquisition unit 696 Second displacement amount acquisition unit 698 Misalignment amount correction unit 700 Auto focus mechanism 710 Auto focus Light flux distribution means 720 Focus shift detection mechanism 730 Focus control unit 740 Motor 800 for auto focus mechanism Detection unit 810 Objective lens 820 Light flux distribution unit for detection unit 830 First detection unit lens 840 Second detection unit lens 910 Branch unit 920 1st displacement amount measuring unit mirror 930 reference member 1000 inspection device A ₁ , A ₂ , A ₃ , A ₄ alignment mark B line and space pattern C solid pattern E optical system field of view F area image G processing block I inspection Region M Mask S Substrate

Claims (2)

An illumination unit having a light source that emits first illumination light;
A branching section that branches the first illumination light into second illumination light and third illumination light;
A reference member having a reference pattern for measuring misalignment;
A detector for detecting the second illumination light and the third illumination light;
An imaging unit for acquiring an optical image of a pattern of a sample to be inspected using the second illumination light and acquiring a reference pattern image of the reference pattern using the third illumination light;
A reference image generation unit that generates a reference image based on pattern data on which the pattern is based;
A comparison unit that compares the optical image with the reference image;
A first misalignment amount acquisition unit that acquires a first misalignment amount using the reference pattern image;
A second misregistration amount acquisition unit that measures a deviation of the optical image from a reference position and acquires a second misregistration amount based on the measured deviation;
A third positional deviation amount is determined based on the comparison result of the comparison unit, the first positional deviation amount, and the second positional deviation amount, and a correction based on the determined third positional deviation amount A positional deviation correction unit for performing
An inspection apparatus comprising:   The inspection apparatus according to claim 1, wherein the reference member is a reflective plate.

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