JP5104438B2 - Periodic pattern unevenness inspection apparatus and method - Google Patents

Description

  The present invention relates to an apparatus and method for inspecting pattern unevenness in an inspection object having a periodic pattern. A periodic pattern refers to an aggregate of patterns having a constant interval. For example, a periodic pattern of stripes in which patterns are arranged at a predetermined pitch, or a pattern of openings is two-dimensionally arranged at a predetermined period. Such a matrix pattern corresponds to this. Examples of the inspection object having a periodic pattern include a photomask used in an exposure process of a photolithography process when manufacturing a semiconductor device, an imaging device, a display device, and the like.

  Conventionally, as a photomask used in a manufacturing process of a semiconductor device, an imaging device, a display device and the like, a photomask that is configured by partially removing a light shielding film such as chromium on a transparent substrate such as glass in a certain pattern is used. Are known.

  Uneven defects in periodic patterns such as photomasks are usually caused by the regular arrangement of fine pitch deviations and positional deviations, and are therefore difficult to find by individual pattern inspection. However, this is a defect recognized for the first time when the periodic pattern is observed in a wide area.

  In the conventional unevenness inspection of periodic patterns, a transmittance image is captured using coaxial transmission illumination or planar illumination, and the normal portion and the unevenness portion are visually recognized by comparing the light intensity in each image. . However, the difference in light intensity between the normal part and the uneven part is not always large, and the contrast of the obtained image is low. For this reason, the contrast difference is improved by devising an intensity difference processing method for an image having a low contrast, and a nonuniformity portion is extracted for inspection (see Patent Document 1).

  However, in the above-described conventional technique, in the imaging of the black matrix unevenness of the lattice-like periodic pattern, particularly the black matrix unevenness having a large opening, the contrast between the normal portion and the uneven portion is not expected to be improved. However, the inspection in the case of an image with a low contrast of the original image has a problem that only an inspection ability lower than the visual sensory inspection method can be achieved.

  On the other hand, due to the miniaturization of semiconductors and the increase in electronic components with fine displays and bright screens, the periodic pattern tends to be miniaturized or the ratio of openings is increased. In the future, a non-uniformity inspection apparatus and method for a periodic pattern having a finer shape and a larger opening will be required. That is, there is a limit in the conventional output with only the intensity (brightness) of light based on the amplitude of light.

  Therefore, for the purpose of providing a periodic pattern unevenness inspection apparatus capable of imaging and detecting a periodic pattern, for example, black matrix unevenness stably and with high accuracy, illumination light is irradiated onto the object to be inspected. For example, an inspection apparatus such as Patent Document 2 for inspecting transmitted diffracted light generated by a pattern has been proposed. In the normal part of the periodic pattern, the shape and pitch of the openings are constant, so that they interfere with each other and generate diffracted light in a certain direction. On the other hand, since the shape and pitch of the opening are irregular in the uneven portion, diffracted light is generated with various intensities in various directions according to the shape and pitch. In this inspection apparatus, a method of detecting a nonuniformity portion from the difference in diffracted light intensity contrast between the normal portion and the nonuniformity portion is adopted.

  By the way, in a periodic pattern, for example, a photomask, pattern miniaturization is rapidly progressing. In particular, in a photomask for a CCD / CMOS imager, the cell pitch at the time of wafer transfer approaches 1 μm. Furthermore, various techniques for improving pattern resolving power have been proposed as technical countermeasures against the progress of pattern miniaturization, and halftone masks have been used as one of them. Unlike a conventional Cr mask, a half-tone mask uses a semi-transmissive film that provides a high contrast at the exposure wavelength, and its transmittance is higher than that of a Cr light-shielding film.

  Further, with the improvement of pattern drawing accuracy in a drawing machine, unevenness caused by minute dimensional deviation and positional deviation on the order of several nanometers has been regarded as a problem. Since the amount of information of the diffracted light contrast difference caused by such a minute fluctuation amount is extremely small, it is necessary to establish an inspection imaging technique with high sensitivity and high resolution corresponding to the information amount.

  On the other hand, with CCD / CMOS imager masks, there is still a high need for unevenness inspection for existing products having a cell pitch of about several tens of μm, and the cell pitch in products to be inspected varies widely. For this reason, the imaging system is required to have a function capable of flexibly changing the inspection imaging magnification.

  Even if the variation amount in the pattern is the same, the pattern variation forms such as dimensional deviation and positional deviation, the appearance of unevenness due to the directionality of the pattern shape, and the contrast strength are different. Therefore, there is a possibility that the number of times of imaging in one product inspection may be multiple times. In order to shorten the tact time required for the inspection as much as possible and realize high throughput, it is desired to secure a wide imaging field of view in one imaging.

The known literature is described below.
JP 2002-148210 A JP 2006-208084 A

  The present invention has been made in view of the above problems, and the object of the present invention is to have a periodic pattern, particularly a cell pitch and pattern directionality as in a photomask for a CCD / CMOS imager. It is an object of the present invention to provide a periodic pattern unevenness inspection apparatus and method capable of imaging and detecting unevenness caused by dimensional displacement and positional displacement on the order of several nanometers with high accuracy.

The invention according to claim 1, which has been made to solve the above-described problem, is a non-uniformity inspection apparatus that inspects a substrate on which a periodic pattern is formed on a substrate, and inspects using diffracted light generated by the periodic pattern. Because
A transport means for mounting the substrate and having a mechanism for driving in the X-axis, Y-axis, and θ-axis directions;
Positioning means for performing predetermined image processing on an image obtained by irradiating light on a predetermined area of the substrate and imaging the predetermined area, and positioning the substrate in the in-plane direction;
Illumination light source means comprising a light source capable of generating visible light as transmitted illumination light;
An illumination head for guiding the transmitted illumination light from the illumination light source means and irradiating the predetermined area with the transmitted illumination light; and
An arc rail that supports the illumination head unit is provided , and the illumination head unit is driven on the arc rail to irradiate transmitted illumination light onto a certain area on the substrate placed on the transport unit. An illumination head driving means capable of controlling an illumination light irradiation angle with respect to a direction perpendicular to the surface to be inspected of the substrate;
Inspection imaging means for imaging diffracted light generated by irradiating the periodic pattern with transmitted illumination light by the illumination head unit;
Image input means using the video output from the positioning means and the video output from the inspection imaging means as image information;
The image information obtained by the image input unit is subjected to defect extraction / determination and analysis processing, and the transport unit, the positioning unit, the illumination light source unit, the illumination head unit, the illumination head drive unit, and the inspection Processing / control means for controlling the operation of the imaging means;
Display means for displaying an image captured by the positioning means and the inspection imaging means, and a processed image by the processing / control means;
A non-uniformity inspection apparatus characterized by comprising:

  In the invention according to claim 2, the positioning imaging means includes a high-luminance spot type LED illumination, irradiates parallel light perpendicular to the inspection target substrate, and is perpendicular to the inspection target substrate. The unevenness inspection apparatus according to claim 1, further comprising an optical system that extracts only reflected light.

  According to a third aspect of the present invention, in the unevenness according to any one of the first and second aspects, the inspection and imaging unit includes a lens having a line sensor camera and an imaging magnification adjustment mechanism. This is an inspection device.

  According to a fourth aspect of the present invention, the illumination head unit irradiates the inspection target substrate with line-shaped parallel light, and the inspection imaging unit inspects out of the diffracted light generated by the periodic pattern. The unevenness inspection apparatus according to claim 1, further comprising an optical system that extracts only diffracted light perpendicular to the target substrate.

  The invention according to claim 5 is the unevenness inspection apparatus according to claim 1, wherein illumination by the illumination head unit is transmitted illumination or reflected illumination. .

  The invention according to claim 6 is characterized in that the illumination light source means is a metal halide lamp, and the amount of light fluctuation with respect to the operating time is 1% or less. This is a non-uniformity inspection apparatus.

  The invention according to claim 7 is characterized in that the illumination light source means has a built-in filter changer part in which a plurality of band pass filters can be installed and the band pass filter can be switched. The unevenness inspection apparatus according to any one of claims 1 to 6 is provided.

  In the invention according to claim 8, the processing / control means includes at least one information processing means, and each information processing means is connected by a local area network and passes through the information distribution means. The unevenness inspection apparatus according to claim 1, wherein the imaging result information and the processing result information can be transmitted to each other.

The invention according to claim 9 uses a diffracted light generated by a periodic pattern, with a substrate having a periodic pattern formed on the substrate as an inspection target, illumination light obliquely incident on the substrate at a plurality of irradiation angles. A non-uniformity inspection method for inspecting
Inspection target substrate information input step for inputting information such as pitch and size of the periodic pattern;
A positioning step for positioning the substrate in the in-inspection direction;
Measurement of the diffracted light generated when the periodic pattern is irradiated with illumination light is performed for illumination at the plurality of irradiation angles, and the diffracted light intensity is obtained at each irradiation angle to obtain a diffracted light intensity profile. Process,
Based on the diffracted light intensity profile obtained in the diffracted light intensity acquisition step and the information on the periodic pattern input in the inspection target substrate information input step, the illumination angle, imaging magnification, and illumination light wavelength An inspection condition setting process for setting
An inspection imaging step for imaging diffracted light generated when the periodic pattern is irradiated with illumination light under the conditions set in the inspection condition setting step;
An image input step using the video output obtained in the inspection imaging step as image information;
An information processing step for performing defect extraction / determination and analysis processing for the image information obtained by the image input step,
This is a non-uniformity inspection method characterized by having

  According to the periodic pattern unevenness inspection apparatus and method of the present invention, a periodic pattern, particularly a test object having a wide range of cell pitches and pattern orientations, such as a photomask for a CCD / CMOS imager. Unevenness caused by dimensional deviation or positional deviation on the order of several nm can be imaged and detected with high accuracy.

  An embodiment of a periodic pattern unevenness inspection apparatus to which the present invention is applied will be described. FIG. 1 is a schematic configuration diagram of an unevenness inspection apparatus 1 according to the present invention. FIG. 1 shows an apparatus configuration example for obtaining transmitted diffracted light. It is desirable that this apparatus be operated in a dark environment where disturbance light and stray light are reduced as much as possible and in a clean environment that prevents foreign matter from adhering to the substrate to be inspected.

  As shown in FIG. 1, this apparatus includes a transmission illumination unit 10, an XY-θ stage unit 20 that can perform a positioning operation of the substrate 60 to be inspected and a scanning operation during inspection imaging, and a positioning of the substrate 60 to be inspected. The imaging unit 30 for alignment for performing the inspection, the inspection imaging unit 40 for imaging the inspection image of the substrate 60 to be inspected, and the processing / control unit 100 are configured.

  The processing / control unit 100 controls the operation of the devices constituting the transmitted illumination unit 10, the XY-θ stage unit 20, the alignment imaging unit 30, and the inspection imaging unit 40, and performs the alignment imaging unit 30 and the inspection imaging. The video output from the unit 40 is input as image information, and arithmetic processing such as image enhancement processing is performed. The first information processing unit 101 and the second information processing unit 104, which are main parts of the processing / control unit 100, exchange image information / inspection information with each other using the information distribution unit 105, and further each process. Results and processed images are displayed on the display means 108 and 109.

  In the transmissive illumination unit 10, an arc rail 11 is installed, a line type illumination head 12 is provided on the arc rail 11, and the light source 13 guides light using a light guide 14. By driving the line-type illumination head 12 on the arc rail 11, the irradiation angle can be adjusted in the direction perpendicular to the surface to be inspected of the substrate 60 to be inspected (this drive axis is defined as the φ axis). The line type illumination head 12 is adjusted so as to be able to irradiate illumination light to a predetermined position on the XY-θ stage unit 20 at any position on the arc rail 11. Transmission illumination from various irradiation angles is possible on the surface to be inspected of the substrate 60 to be inspected on the −Y−θ stage unit 20.

  The line illumination head 12 is provided with a parallel optical system. The light source 13 is provided with a filter changer mechanism, and a plurality of wavelength selection filters can be used. In the present embodiment, a metal halide lamp is used as the light source 13, and a light amount fluctuation range with respect to the operation time is 1% or less and a light amount stability is high.

  FIG. 2 schematically shows the XY-θ stage unit 20. The inspected substrate 60 is placed at a predetermined position of the XY-θ stage unit 20. The inspected substrate 60 mounting portion is characterized by being hollow.

  The XY-θ stage unit 20 has a function of translating the inspected substrate 60 in the X-axis direction and the Y-axis direction of FIG. 2 and a function of rotating the inspected substrate 60 by 360 ° within the surface to be inspected. (This axis of rotation is the θ axis.) As a result, the inspected substrate 60 is driven in the X-axis and Y-axis directions according to a preset operation procedure. Further, by rotating the inspected substrate 60 around the θ axis, the illumination irradiation direction of the inspected surface of the inspected substrate 60 can be adjusted.

  The driving in the Y-axis direction serves both for transporting the substrate 60 to be inspected and for driving during scanning for inspection imaging. It is desirable that the driving at the time of scanning is ensured at a constant speed, and it is further desirable to have a high-precision positioning mechanism using a linear encoder or the like. Further, it is desirable that a vibration isolation function is provided on the stage side so that there is no problem even if the depth of field values of the alignment imaging unit 30 and the inspection imaging unit 40 are small to some extent.

  The alignment imaging unit 30 includes a camera 31, a lens 32, an illumination 33, and an illumination control device 34. Illumination light is radiated to the region including the alignment mark on the inspected substrate 60 in the coaxial epi-illumination format, and the observation image is captured by the camera 31. Note that the illumination control device 34 can turn on / off the illumination and adjust the illumination light intensity, and the actual control operation is performed by the processing / control unit 100. In this embodiment, the camera 31 is an area CCD camera, the lens 32 is a coaxial incident type fixed magnification telecentric lens, and the illumination 33 is a high brightness spot type white LED.

  The inspection imaging unit 40 includes a camera 41 as a means for imaging an image and an imaging side parallel optical system 42. As the camera 41, a line sensor camera having various numbers of pixels can be used. However, it is desirable that the number of pixels is as high as possible in order to secure a certain imaging field of view. Is possible.

  The camera exposure time during imaging needs to be adjusted according to the imaging magnification. Although the camera exposure time can be changed by adjusting the camera line rate, care must be taken so that the stage speed does not exceed the upper limit value because the stage speed during imaging depends on the camera line rate. In this embodiment, the camera 41 uses a line sensor camera of 8192 pixels. However, if the brightness in the captured image cannot be secured even using the camera exposure time adjustment function, the TDI line sensor camera may be used. Good. In addition, by providing a plurality of cameras with different performances and a camera switching mechanism, it may be possible to select an optimal one for each inspection by switching the camera used.

  The imaging side parallel optical system 42 uses an electric zoom lens having a variable optical magnification, but may have an automatic aperture adjustment function. Although the imaging magnification depends on the cell pitch of the periodic pattern on the substrate 60 to be inspected, it is desirable that the imaging magnification is secured from a low magnification range of about 0.2 times to a high magnification range of about 3 times.

  In the processing / control unit 100, the first information processing unit 101 performs operation management and control of the transmitted illumination unit 10, the XY-θ stage unit 20, the alignment imaging unit 30, and the inspection imaging unit 40. Further, the first information processing means 101 captures the video output from the alignment imaging unit 30 and the inspection imaging unit 40 as image information digitized by the image input devices 102 and 103, and digitizes the image information feature amount. Detecting mura defects. The second information processing unit 104 performs data processing such as pass / fail judgment and addition processing for the result processed by the first information processing unit 101.

  Data processing procedures include noise removal processing such as shading correction and expansion / contraction processing, image enhancement processing such as filtering processing, feature amount extraction processing such as a projection method, defect image extraction processing, and composite processing thereof. Is mentioned. Further, by constructing a local area network in the apparatus, it is possible to exchange data between 101 and 104 of image information and processing information obtained by inspection imaging via the information distribution means 105. It is possible to read / write processing information from the first information processing unit 101 and the second information processing unit 104 to the external storage device 106 each time. Furthermore, by connecting to the higher-level information distribution unit 107, it is possible to share information with other manufacturing apparatuses and to transmit the apparatus operating status.

  FIG. 3 is a flowchart showing the inspection method according to the embodiment of the present invention. The inspection method according to the embodiment of the present invention is performed by a series of steps S1 to S20. Hereinafter, the contents of each step will be described in the order of steps.

  The entire apparatus is started up, such as turning on the apparatus power and initializing the apparatus (S1).

  Cell pitch, chip layout, management No. in the inspected substrate 60. Is read into the first information processing unit 101 via the higher-level information distribution unit 107 or directly input to the first information processing unit 101 (S2).

  The inspected substrate 60 is placed and fixed at a predetermined position of the XY-θ stage 20 (S3).

  The XY-θ stage 20 is driven to move the inspected substrate 60 to the position of the alignment imaging unit 30 (S4).

  An alignment operation for the inspected substrate 60 is performed by adjusting the X, Y, and θ axes and the alignment imaging unit 30 (S5).

  After the alignment operation is completed, the XY-θ stage 20 is moved to the position of the inspection imaging unit 40 (S6).

  Using the inspection imaging unit 40 and the transmitted illumination unit 10, the diffracted light intensity at the inspected substrate 60 is measured with respect to a plurality of values of φ at a predetermined θ-axis position corresponding to the periodic pattern arrangement direction. A light intensity profile is obtained (S7).

  An example of a method for acquiring a diffracted light intensity profile when a line camera is used as the camera 41 is schematically shown in FIG.

  The arc rail 11 is driven in a range of φ = 0 ° to 60 °, and illumination light is projected onto the substrate 60 to be inspected. At that time, the intensity of diffracted light generated in the periodic pattern on the substrate 60 to be inspected continuously changes. This diffracted light intensity change is acquired by performing scanning imaging in a state where the operation of the arc rail 11 and the exposure timing of the line camera are synchronized. At this time, the inspected substrate 60 remains fixed.

  The acquired diffracted light intensity change is captured as image information into the first information processing means 101 via the image input device 102, and an image image is formed. At this time, the number of pixels in the vertical direction of the image is the number of times of exposure imaging within the driving angle range of the arc rail (in FIG. 4, the case where the angular step width is 0.5 ° is shown).

  A line profile of luminance values is created for the image image obtained in this way in the vertical direction of the image. At this time, the line profile in the vertical direction of the image for all the number of pixels in the width direction (8192 pixels in the figure). And an average profile divided by the number of pixels in the width direction may be used. Predetermined data processing such as data interpolation and smoothing is performed on the obtained profile to create a diffracted light intensity profile.

  A diffracted light intensity peak with respect to φ is calculated from the product information input in S2 (S8).

  From the comparison between the diffracted light intensity profile peak position obtained in S7 and the diffracted light intensity peak calculated in S8, the transmitted illumination angle condition on the φ axis is determined (S9).

  Based on the product information input in S2, imaging conditions such as imaging magnification and camera line rate are determined (S10).

  After the setting of the inspection conditions in S7 to S10 is completed, the XY-θ stage 20 is driven according to a predetermined operation, and image information is acquired by imaging with the camera 41. Further, a plurality of inspection images may be acquired by repeating imaging in the same range a plurality of times. When imaging is performed a plurality of times as described above, the settings of the transmission illumination unit and the imaging unit may be changed to different settings for each imaging, and inspection images under a plurality of different inspection conditions may be acquired (S11). .

  With respect to the inspection image obtained as described above, the first information processing unit 101 performs noise removal processing such as shading correction and expansion / contraction processing, image enhancement processing by filtering processing, etc., feature amount by projection method, etc. Various data processing such as extraction processing and uneven defect image cutout is performed, the feature amount of the inspection image is digitized, and the inspection result for the inspected substrate 60 is output to the external storage device 106. Note that the output inspection result may be viewable from a designated external terminal via the higher-level information distribution unit 107 (S12 to S14).

  Furthermore, the second information processing means 104 is utilized as necessary to perform a review process for judging the validity of the result of the mura defect classification and numerical value for the inspection result. The second information processing unit 104 is connected to the external storage device 106 via the information distribution unit 105 to read the mura defect image and the inspection result information. A review process is executed based on the read information, a final determination process is performed, and an inspection result is output (S15, S16).

  After the inspection of the inspected substrate 60 is completed by these procedures, the XY stage is moved to the initial position, the inspected substrate 60 is unloaded, the entire apparatus is lowered, and the periodic pattern in the present apparatus is obtained. This completes the unevenness inspection process (S17 to S20).

  A series of operations in each process described above is executed by an operation by the interpersonal operation devices 110 and 111 or by a program incorporated in advance, and the inspection progress information, output results, and the like are displayed on the display devices 108 and 109.

  The periodic pattern unevenness inspection apparatus described above is characterized in that it picks up transmitted diffracted light in a periodic pattern, which is generated by performing light projection from an oblique direction.

  In the periodic pattern unevenness inspection apparatus configured as described above, the light emitted from the transmission illumination unit 10 is diffracted by the periodic pattern of the substrate 60 to be inspected, and the diffracted light is imaged as the inspection imaging unit 40. Is captured by. In the diffracted light, there is an effect that the difference in the shape or pitch of the slit or opening is emphasized, and the difference in the diffracted light is also emphasized by gradually changing the incident angle of illumination.

  If the diffracted light diffracted by the substrate 60 to be inspected has a slight variation in the line width or slit width of the photomask or black matrix, the size or positional deviation of the pattern, the diffraction angle of the light changes in the variation portion Therefore, the image captured by the inspection imaging unit 40 is an image in which unevenness caused by the variation unit is emphasized (schematically illustrated in FIG. 5). Furthermore, by using a parallel optical system for the transmitted illumination unit 10 and the inspection imaging unit 40, it is possible to capture an image in which fluctuations of diffracted light are emphasized with higher accuracy.

  FIG. 6 schematically shows an example of non-uniformity visualization when a photomask is inspected as a substrate 60 to be inspected by a line sensor camera. The CCD cell size of the line sensor camera used here is 7 μm, and the imaging magnification at this time is 0.35 times. Therefore, the imaging resolution is 20 μm. At this time, the camera visual field width is about 163 mm, and it is possible to acquire the mura defect image on the entire photomask in a short time by one scan imaging. In this case, when imaging is performed on a 6-inch photomask, the time required for one scan is within one second.

  As described above, dimensional deviations and positional deviations on the order of several nanometers are inspected for periodic patterns, particularly test objects having a wide range of cell pitches and pattern orientations, such as photomasks for CCD / CMOS imagers. It is possible to image and detect the unevenness caused by the high accuracy.

  In addition, by adopting a light source that has a light amount fluctuation range of 1% or less with respect to the operation time and a high light amount stability, it is possible to ensure the stability of the image acquired by inspection and the reproducibility of the inspection result.

  By displaying the determined type of unevenness, the position and level of the unevenness on the display devices 108 and 109 at the same time as the unevenness image, the use for unevenness monitoring is also effective.

As described above, according to the embodiment of the present invention, it is possible to detect the irregularity of the periodic pattern stably and with high accuracy.

It is a schematic diagram which shows schematic structure of the nonuniformity inspection apparatus of the periodic pattern of this invention. 2 is a schematic diagram of an XY-θ stage section 20 in the present invention. FIG. It is a flowchart figure which shows embodiment of the test | inspection method of this invention. It is a schematic diagram of the example of a diffracted light intensity profile acquisition means in this invention. It is a schematic diagram of an example of periodic pattern unevenness visualization by diffracted light in the present invention. It is the figure which showed typically the example of nonuniformity visualization in the case of using a photomask as a to-be-inspected board | substrate in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Transmitting illumination part 11 Arc rail 12 Line type illumination head 13 Light source 14 Light guide 20 XY-theta stage part 30 Alignment imaging part 31 Camera 32 Lens 33 Illumination 34 Illumination control device 40 Inspection imaging part 41 Camera 42 Imaging side parallel Optical system 60 Inspected substrate 100 Processing / control unit 101 First information processing means 102 Image input device 103 Image input device 104 Second information processing means 105 Information distribution means 106 External storage device 107 Upper side information distribution means 108 Display means 109 Display means 110 Interpersonal operation means 111 Interpersonal operation means 112 Printer

Claims (9)

A non-uniformity inspection apparatus that inspects a substrate on which a periodic pattern is formed on a substrate, and inspects using diffracted light generated by the periodic pattern,
A transport means for mounting the substrate and having a mechanism for driving in the X-axis, Y-axis, and θ-axis directions;
Positioning means for performing predetermined image processing on an image obtained by irradiating light on a predetermined area of the substrate and imaging the predetermined area, and positioning the substrate in the in-plane direction;
Illumination light source means comprising a light source capable of generating visible light as transmitted illumination light;
An illumination head for guiding the transmitted illumination light from the illumination light source means and irradiating the predetermined area with the transmitted illumination light; and
An arc rail that supports the illumination head unit is provided , and the illumination head unit is driven on the arc rail to irradiate transmitted illumination light onto a certain area on the substrate placed on the transport unit. An illumination head driving means capable of controlling an illumination light irradiation angle with respect to a direction perpendicular to the surface to be inspected of the substrate;
Inspection imaging means for imaging diffracted light generated by irradiating the periodic pattern with transmitted illumination light by the illumination head unit;
Image input means using the video output from the positioning means and the video output from the inspection imaging means as image information;
The image information obtained by the image input unit is subjected to defect extraction / determination and analysis processing, and the transport unit, the positioning unit, the illumination light source unit, the illumination head unit, the illumination head drive unit, and the inspection Processing / control means for controlling the operation of the imaging means;
Display means for displaying an image captured by the positioning means and the inspection imaging means, and a processed image by the processing / control means;
A nonuniformity inspection apparatus comprising:
  The positioning means includes a high-luminance spot type LED illumination, and an optical system that irradiates parallel light perpendicularly to the inspection target substrate and extracts only vertical reflected light from the inspection target substrate. The unevenness inspection apparatus according to claim 1, wherein:   The unevenness inspection apparatus according to claim 1, wherein the inspection imaging unit includes a lens having a line sensor camera and an imaging magnification adjustment mechanism.   The illumination head unit irradiates the inspection target substrate with line-shaped parallel light, and the inspection imaging unit is perpendicular to the inspection surface of the substrate among the diffracted light generated by the periodic pattern of the substrate. The unevenness inspection apparatus according to claim 1, further comprising an optical system that extracts only diffracted light.   The unevenness inspection apparatus according to claim 1, wherein the illumination by the illumination head unit is transmitted illumination or reflected illumination.   The unevenness inspection apparatus according to claim 1, wherein the illumination light source means is a metal halide lamp, and a light amount fluctuation width with respect to an operation time is 1% or less.   The illumination light source means includes a plurality of band-pass filters therein, and a built-in filter changer unit capable of switching the band-pass filters. The unevenness inspection apparatus described.   The processing / control means includes at least one information processing means, and each information processing means is connected by a local area network, and transmits imaging result information / processing result information via the information distribution means. The unevenness inspection apparatus according to claim 1, wherein the non-uniformity inspection apparatus can perform each other. A non-uniformity inspection method in which a substrate having a periodic pattern formed on a substrate is an inspection target, illumination light is obliquely incident on the substrate at a plurality of irradiation angles, and inspection is performed using diffracted light generated by the periodic pattern,
Inspection target substrate information input step for inputting information such as pitch and size of the periodic pattern;
A positioning step for positioning the substrate in the in-inspection direction;
Measurement of the diffracted light generated when the periodic pattern is irradiated with illumination light is performed for illumination at the plurality of irradiation angles, and the diffracted light intensity is obtained at each irradiation angle to obtain a diffracted light intensity profile. Process,
Based on the diffracted light intensity profile obtained in the diffracted light intensity acquisition step and the information on the periodic pattern input in the inspection target substrate information input step, the illumination angle, imaging magnification, and illumination light wavelength An inspection condition setting process for setting
An inspection imaging step for imaging diffracted light generated when the periodic pattern is irradiated with illumination light under the conditions set in the inspection condition setting step;
An image input step using the video output obtained in the inspection imaging step as image information;
An information processing step for performing defect extraction / determination and analysis processing for the image information obtained by the image input step,
A method for inspecting unevenness, characterized by comprising: