JP5123003B2 - Inspection apparatus and inspection method - Google Patents

Description

  The present invention relates to a semiconductor inspection apparatus and inspection method mainly used in a semiconductor manufacturing process.

  In a semiconductor manufacturing process, if foreign matter or pattern defects exist on a semiconductor substrate (wafer), it may cause defects such as wiring insulation failure or short circuit.

  Further, when fine foreign matter is present as the semiconductor element is miniaturized, the finer foreign matter may cause failure of insulation of the capacitor or destruction of the gate oxide film.

  These foreign substances are mixed in various states, such as those generated from the moving parts of the transfer device, those generated from the human body, those generated by reaction in the processing apparatus by the process gas, and those containing chemicals and materials. Is done.

  Similarly, in the manufacturing process of the liquid crystal display element, if a foreign substance adheres to the pattern or some defect occurs, the liquid crystal display element cannot be used as a display element. The situation is the same in the manufacturing process of the printed circuit board, and the adhesion of foreign matters causes short circuit of the pattern and defective connection.

  Conventionally, as one of techniques for detecting fine foreign matters and defects on a semiconductor substrate of this kind at high speed and with high sensitivity, as described in Patent Document 1, a laser is irradiated on the semiconductor substrate and the semiconductor substrate is exposed. By detecting scattered light from foreign matter generated when foreign matter is attached to the surface and comparing it with the inspection result of the same type semiconductor substrate that was inspected immediately before, there is no false information due to the pattern, and high sensitivity and high reliability What enables foreign matter and defect inspection is disclosed.

  As in Patent Document 1, in order to perform comparative inspection of a substrate to be inspected at high speed and with high sensitivity, a highly accurate inspection stage and position correction control technology are required. As an example of the stage position correction technique as described above, there is an example of an XY stage position correction control method using a reference mask described in Patent Document 2 as an example of a semiconductor manufacturing apparatus.

JP-A-62-89336 JP 7-325623 A

  In the prior art, in order to detect foreign matter and pattern defects on a semiconductor substrate to be miniaturized at high speed, it is necessary to minimize the amount of positional deviation of the inspection stage projected on the inspection image. A highly accurate inspection stage has been required.

  In addition, it is necessary to suppress the cost increase accompanying the improvement of the accuracy of the inspection stage.

  The present invention addresses the above-described problems and adjusts and corrects the position correction of a captured image obtained by photographing the object to be inspected and the orientation of the image sensor for photographing the object to be inspected without relying solely on the stage misalignment correction control. Accordingly, it is an object of the present invention to provide an inspection method and an inspection apparatus that can detect foreign matter and pattern defects with high speed and high accuracy, and can suppress cost increase.

  The present invention provides an inspection method in which an inspected object mounted on a moving stage is imaged and inspected by an image sensor to obtain a positional deviation amount between the target position and the actual position of the stage moving toward imaging, In photographing at the target position, the orientation of the image sensor relative to the object to be inspected is adjusted and corrected according to the amount of positional deviation.

  Further, the present invention relates to an inspection method in which an inspection object mounted on a moving stage is imaged with an image sensor, and the positional deviation amount between the target position and the actual position of the stage moving toward imaging is obtained and imaged. When the captured image is cut out from the shooting range of the target position, the cut-out position correction corresponding to the positional deviation amount is performed.

  According to the present invention, foreign matter and pattern defects can be detected with high speed and high accuracy, and the cost can be suppressed.

  Embodiments of the present invention will be described below with reference to the drawings.

  In the following drawings, equivalent functional parts will be described with the same reference numerals.

  Next, the apparatus configuration of the inspection apparatus according to the first embodiment of the present invention will be described with reference to FIGS.

  An embodiment of the defect inspection apparatus will be described.

  The defect inspection apparatus includes a substrate 1 to be inspected, a beam spot 3 which is a slit-like illumination region irradiated on the substrate to be inspected in a slit shape, a detection region 4 of the image sensor, and an inspection region in the substrate to be inspected in the XY direction. A stage unit composed of an X stage 301 and a Y stage 302 that can be moved relative to the optical system, a Z stage 303 that can focus on the surface of the substrate to be inspected, a theta (θ) stage 304, and a stage controller 305 300.

  The illumination optical system 100 includes a laser light source, a beam expander, an optical filter group and mirror, an optical branching element (or mirror) switchable with a glass plate, and a beam spot imaging unit.

  Further, a detection lens 201, a spatial filter 202, an imaging lens 203, a zoom lens group 204, a one-dimensional image sensor (image sensor) 205, an upper inspection system 206 capable of observing a detection area of the image sensor, a polarization beam splitter 209, and two sensors. The detection optical system 200 includes a branch detection optical system 210 for simultaneous inspection.

  Furthermore, an A / D conversion unit, a data memory that can be delayed, a difference processing circuit that takes a signal difference between chips, a memory that temporarily stores a difference signal between chips, a threshold value calculation processing unit that sets a pattern threshold value , A signal processing unit 402 composed of a comparison circuit, an output means for storing a defect detection result of a foreign substance and the like and outputting a defect detection result, a control CPU unit 401 for controlling driving, coordinates, and sensors of a motor and the like, a display unit 403 And a control system 400 including an input unit 404.

  As the laser light source of the illumination optical system 100, it is preferable to use the third harmonic THG of a high-power YAG laser and a wavelength of 355 nm, but it is not necessarily required to be 355 nm. That is, other light sources such as a laser light source Ar laser, a nitrogen laser, a He—Cd laser, and an excimer laser may be used.

  The one-dimensional image sensor 205 may be a CCD or a TDI (Time Delay Integration) sensor. In the case of a CCD, since the pixel size is about 10 μm, it may be considered as linear detection, and there is no sensitivity reduction due to capturing an image that is not in focus in the scanning direction.

  On the other hand, in TDI, since images for a certain number of pixels are accumulated in the scanning direction, it is desirable to reduce the amount of images that are not in focus by taking measures such as reducing the illumination width or tilting the TDI sensor.

  The coordinate system is shown in the lower left of FIG. The XY axis is taken on the plane, and the Z axis is taken vertically upward. The optical axis of the detection optical system 200 is arranged along the Z axis.

  First, with reference to FIG. 2, a sample that is an inspection target of the defect inspection apparatus according to the embodiment of the present invention will be described.

  A substrate 1a to be inspected shown in FIG. 2A has memory LSI chips 1aa arranged two-dimensionally at a predetermined interval. The memory LSI chip 1aa mainly has a memory cell area 1ab, a peripheral circuit area 1ac composed of a decoder, a control circuit, and the like, and another area 1ad.

  The memory cell region 1ab has a two-dimensional regular arrangement, that is, a repeated memory cell pattern. Peripheral circuit region 1ac has a non-repetitive pattern that is not regularly arranged two-dimensionally.

  A substrate to be inspected 1b shown in FIG. 2B has LSI chips 1ba such as a microcomputer arranged two-dimensionally at a predetermined interval.

  An LSI chip 1ba such as a microcomputer mainly includes a register group area 1bb, a memory area 1bc, a CPU core area 1bd, and an input / output area 1be. FIG. 2B conceptually shows the arrangement of the memory area 1bc, the CPU core area 1bd, and the input / output area 1be.

  The register group region 1bb and the memory portion region 1bc are regularly arranged in two dimensions, that is, have a repetitive pattern. The CPU core area 1bd and the input / output area 1be have non-repeating patterns.

  As described above, the inspection target of the defect inspection apparatus according to the embodiment of the present invention has chips regularly arranged as in the inspection target substrate (wafer) 1 shown in FIG. The minimum line width is different for each region, and includes various patterns including a repetitive pattern and a non-repetitive pattern.

  With reference to FIG. 3, the first to third beam spot imaging units 110, 120, and 130 of the illumination optical system 100 will be described.

  FIG. 3 is a view of the substrate to be inspected from above.

  The inspection illumination light 11 in the X-axis direction is irradiated through the first beam spot imaging unit 110, and the direction is inclined by −45 degrees with respect to the Y-axis through the second beam spot imaging unit 120. And the inspection illumination light 13 in the direction inclined by 45 degrees with respect to the Y axis is irradiated via the third beam spot imaging unit 130.

  The non-repeating pattern on the substrate to be inspected mainly consists of linear patterns formed in parallel and at right angles. These linear patterns extend in the X-axis or Y-axis direction. Since the pattern on the substrate 1 to be inspected is formed to protrude, a recess is formed between adjacent linear patterns.

  Therefore, the inspection illumination lights 12 and 13 irradiated from the direction inclined by 45 degrees with respect to the X axis and the Y axis are blocked by the protruding circuit pattern and cannot irradiate the concave portion between the linear patterns.

  These inspection illumination lights 11, 12, and 13 are irradiated at a predetermined elevation angle α with respect to the surface on the substrate to be inspected. In particular, the amount of scattered light detected from the lower surface of the transparent thin film can be reduced by reducing the elevation angle α of the illumination lights 12 and 13 for inspection.

  These inspection illumination lights 11, 12, 13 form an elongated beam spot 3 on the substrate to be inspected. The beam spot 3 extends along the Y-axis direction. The length of the beam spot 3 in the Y-axis direction is larger than the detection area 4 of the image sensor of the one-dimensional image sensor 205 of the detection optical system 200.

  The reason why the three beam spot imaging units 110, 120, and 130 are provided in the illumination optical system 100 will be described. In the present example, φ1 = φ2 = 45 degrees, assuming that the angles formed by the images obtained by projecting the inspection illumination lights 12 and 13 on the XY plane and the X axis are φ1 and φ2, respectively.

  As a result, the main direction of the non-repeated pattern on the substrate to be inspected is an X-axis or Y-axis linear pattern, and is incident on the pattern from a 45 degree direction.

  For this reason, the 0th-order diffracted light enters the entrance pupil of the detection lens 201 as a component of the X-axis or Y-axis direction. However, when the illumination elevation angle α is a low angle, the regular reflection light is also a low angle α. Similarly, the diffracted light of the axis or Y component is also separated from the entrance pupil region of the detection lens 201, so that it can be prevented from entering the detection optical system 200. For example, in Japanese Patent No. 3566589 (see columns 0033 to 0036). This is described in detail, and a description thereof is omitted here.

  The non-repeating pattern on the substrate to be inspected mainly consists of linear patterns formed in parallel and at right angles. These linear patterns extend in the X-axis or Y-axis direction. Since the pattern on the substrate to be inspected is formed to protrude, a recess is formed between adjacent linear patterns.

  Therefore, the inspection illumination lights 12 and 13 irradiated from the direction inclined by 45 degrees with respect to the X axis and the Y axis are blocked by the protruding circuit pattern and cannot irradiate the concave portion between the linear patterns.

  Therefore, a first beam spot imaging unit 110 that generates the inspection illumination light 11 along the X-axis direction is provided. In this way, the inspection illumination light 11 can irradiate the recesses between the linear patterns, so that it is possible to detect a defect such as a foreign substance existing there.

  Depending on the direction of the linear pattern, the sample may be inspected by rotating 90 degrees, or the inspection illumination light 11 may be irradiated along the Y-axis direction.

  In addition, when irradiating along the X-axis direction and irradiating the concave portions between the linear patterns as in the case of the inspection illumination light 11, the 0th order diffracted light is not detected by the image sensor. It is necessary to shield the diffracted light. For this purpose, a spatial filter 202 is provided.

  A method for forming the elongated beam spot 3 will be described with reference to FIGS.

  4 and 5, only the laser light source 101, the concave lens 102, the convex lens 103, and the illumination lens 104 are shown in the illumination optical system 100, and other components are omitted.

  The illumination lens 104 is a cylindrical lens having a conical curved surface, and as shown in FIG. 4A, the focal length changes linearly along the longitudinal direction, and as shown in FIG. It has a cross section of a convex lens.

  As shown in FIG. 5, it is possible to generate a slit-shaped beam spot 3 that is narrowed down in the Y direction and collimated in the X direction even with respect to illumination light that is inclined and incident on the substrate to be inspected. The angle of the illumination light with respect to the surface of the substrate to be inspected is α1, and the angle between the image of the inspection illumination light 11 projected on the substrate to be inspected and the X axis is φ1.

  By using such an illumination lens 104, it is possible to realize illumination having parallel light in the X direction and around φ1 = 45 degrees. The manufacturing method and the like of the illumination lens 104 having a conical curved surface are described in detail in, for example, Japanese Patent No. 3566589 (refer to paragraph No. 0027 to paragraph No. 0028), and can be manufactured by a known method.

  Furthermore, Example 1 is demonstrated in detail using FIGS. 6-10 and FIG. This embodiment relates to image processing according to the present invention.

  The object of the present embodiment is an embodiment in which the positional deviation amount with respect to the target position of the stage obtains an effect equal to or higher than that obtained by performing the alignment of the imaging range by image processing and inspecting with the high precision stage.

  FIG. 6 is a partial detail view of the stage unit 300 of FIG.

  FIG. 7 is a stage origin moving distance setting map for moving the X stage 302 and the Y stage 301 to the target coordinates.

  FIG. 8 is a map obtained by measuring the actual movement distance from the stage origin when the X stage 302 and the Y stage 301 are moved along the movement distance setting map of FIG.

  FIG. 9 is a diagram illustrating a device configuration of the present embodiment, and is a configuration diagram in which a storage unit 405 and an image processing unit 406 are added to the device configuration of FIG.

  FIG. 10 is a diagram showing an imaging range 600 at the time of inspection, a comparative inspection image 610 after position correction, and an image comparison inspection result 620.

  FIG. 14 shows a flowchart of the present embodiment.

  Hereinafter, this embodiment will be described in detail with reference to the flowchart of FIG.

  As step S1, laser length measuring devices 310 to 314 are set on the stage unit 300 shown in FIG. The laser length measuring devices 310 to 314 may be removed after the measurement of the stage displacement amount, but may be left mounted on the stage unit 300.

  Further, although the accuracy is somewhat lowered, linear scales 320 and 321 may be arranged on the X stage 302 and the Y stage 301, respectively.

  As step S2, the X stage 302 and Y stage 301 of the stage unit 300 shown in FIG. 6 are moved at a constant pitch (X1, Y1) with respect to the movement target position A1 along the movement distance setting map of FIG.

  For the movement amount along the movement distance setting map, the encoders of the X stage 302 and the Y stage 301 or the coordinates of the stage linear scales 320 and 321 may be used. At this time, the movement position (X1 ′, Y1 ′) of the actually moved position A1 ′ shown in FIG. 8 is measured.

  Similarly, it is moved at a constant pitch (Xn, Yn) with respect to the movement target position An, the movement position (Xn ′, Yn ′) of the actually moved position An ′ is measured, and the movement distance map from the stage origin in FIG. To complete.

  As step S3, the difference ΔX, ΔY of the actual movement amount with respect to the movement target position is obtained from the data collected in step S2. An example of the calculation formula is shown below.

(Example)
Difference ΔX of X stage 302 = (X1) − (X1 ′) (Equation 1)
Difference of Y stage 301 ΔY = (Y1) − (Y1 ′) (Equation 2)
By making the measurement pitch of the movement distance measurement map from the stage origin in FIG. 7 fine, the amount of positional deviation due to the pitch deviation from the repetitive pattern of the substrate 1 to be inspected can be minimized.

  In step S4, the difference ΔX, ΔY in the stage position deviation amount is stored in the storage unit 405 shown in FIG. 9 as the position correction values ΔX ′, ΔY ′ of the inspection image. In step S5, the inspected substrate 1 shown in FIG. 9 is inspected, and inspection images 601 to 604 in the imaging range 600 shown in FIG. 10 are captured.

  In step S <b> 6, the image processing unit 406 illustrated in FIG. 9 cuts out the inspection images 611 to 614 from the imaging range 600 to create a comparative inspection image 610. In this cut-out, correction is performed using the position correction values ΔX ′ and ΔY ′ of the inspection image previously stored in the storage unit 405, so that the comparison inspection image 610 with the corrected positional deviation amount is obtained.

  Since the imaging range 600 at the target position is larger than the captured image (cut-out inspection image) cut out in anticipation of the stage position shift amount (position shift amount), the inspection image covering the entire inspection range can be cut out.

  In step S7, the comparison inspection image 610 is compared by the signal processing unit 402 shown in FIG. 9, and foreign matter, defect A, and defect B are detected from the image comparison inspection result 620 shown in FIG. In step S8, the detection result of step S7 is displayed on the display unit 403.

  In this method, the inspected substrate 1 is enlarged and inspected by the zoom lens group 204 shown in FIG.

  For example, if the stage displacement amount is 5 μm and the zoom lens magnification is 5 to 20 times, the stage displacement amount can be enlarged to 25 μm to 100 μm and recognized. Conversely, when the zoom lens magnification is low, the amount of movement is small and control is easy.

  Therefore, the required accuracy of position correction with respect to the stage position deviation amount can be relaxed, and the position correction can be easily performed with the inspection image. Furthermore, the stage required accuracy can be relaxed because the position deviation amount can be easily corrected by the inspection image.

  Furthermore, since the θ stage 304 or its vicinity away from the X stage 302 and the Y stage 301 is directly measured by a laser measuring instrument, it is possible to improve the correction accuracy of the amount of misalignment due to stage yawing, pitching and rolling. .

  Further, in the comparative inspection in which the position correction is not performed by the inspection image using the conventional high-precision stage, a comparison process in which the position displacement amount of the stage is considered in the comparison pixel number of the image sensor, for example, the displacement amount for 3 pixels is set. In this method, the number of comparison pixels of the image sensor can be compared with a single pixel, so the image comparison accuracy is improved and foreign objects and defects that have been missed in the conventional comparison process. Can be detected.

  Further, by performing sub-pixel alignment during undersampling, it is possible to perform comparison processing within one pixel.

  Further, in the conventional method, as a problem due to the DF (dark field) inspection apparatus, a non-inspection area is low or low in order to inspect the vicinity of a dark part of a pattern or a position where an inspection image of a saturated part is misaligned. Although it is necessary to inspect with sensitivity, this method has an effect of reducing the non-inspection region and the low sensitivity region.

  This system is a method suitable for an apparatus that has a repetitive pattern and performs comparative inspection as long as the apparatus includes an XY stage and an image sensor.

  Embodiments relating to imaging range control according to the present invention will be described with reference to FIGS. 6 to 9, FIGS. 11 to 13, and FIG. 15.

  The purpose of this embodiment is to align the inspection image by controlling the position shift amount with respect to the target position of the stage with an image sensor, and to obtain an effect equivalent to or higher than that of the inspection with a high-precision stage. is there.

  Since FIG. 6 to FIG. 9 are described in the first embodiment, description thereof is omitted.

  FIG. 11 is a diagram illustrating an apparatus configuration of the second embodiment.

  FIG. 12 is a detailed diagram of the image sensor position correction unit of the present embodiment.

  FIG. 13 is a diagram showing an imaging range 700 at the time of inspection, a comparative inspection image 710 after position correction, and an image comparison inspection result 720.

  FIG. 15 is a diagram showing a flowchart of the present embodiment.

  Hereinafter, this embodiment will be described in detail with reference to the flowchart of FIG.

  As step S11, the laser length measuring devices 310 to 314 are set on the stage unit 300 shown in FIG.

  The laser length measuring devices 310 to 314 may be removed after the measurement of the stage displacement amount, but may be left mounted on the stage unit 300.

  As step S12, the X stage 302 and Y stage 301 of the stage unit 300 shown in FIG. 6 are moved at a constant pitch (X1, Y1) with respect to the movement target position A1 along the movement distance setting map of FIG.

  At this time, the movement position (X1 ′, Y1 ′) of the actually moved position A1 ′ shown in FIG. 8 is measured.

  Similarly, it is moved at a constant pitch (Xn, Yn) with respect to the movement target position An, the movement position (Xn ′, Yn ′) of the actually moved position An ′ is measured, and the movement distance map from the stage origin in FIG. To complete.

  In step S13, the difference ΔX, ΔY of the actual movement amount with respect to the movement target position is obtained from the data collected in step S12. As the calculation formula, (Equation 1) and (Equation 2) described in Example 1 are used.

  In step S14, the difference ΔX, ΔY in the stage position deviation amount is stored in the storage unit 405 shown in FIG. 11 as the position correction values ΔX ′, ΔY ′ of the image sensor 205.

  In step S15, control is performed by referring to the position correction values ΔX ′, ΔY ′, ΔX1 ′, ΔY1 ′, ΔX2 ′, ΔY2 ′, ΔX3 ′, ΔY3 ′ of the image sensor 205 shown in FIG. Like the inspection images 701 to 704 in the imaging range 700 shown in FIG. 13, the CPU 401 performs the inspection operation of the inspected substrate 1 while performing position correction control by the image sensor position correction unit 500 shown in FIG. 12.

  The image sensor position correction unit 500 includes an XY correction mechanism 501, an X-axis motor 502, and a Y-axis motor 503.

  The image sensor position correction unit 500 adjusts and corrects the above-described positional deviation amount (difference amount between the target position of the stage and the actual position). The image sensor 205 is moved in parallel with the stage in the X-axis / Y-axis directions by the XY correction mechanism 501 to perform adjustment correction of the positional deviation amount.

  Instead of this parallel movement method, it is also possible to perform adjustment correction of the positional deviation amount by adjusting the orientation angle with respect to the stage.

  Now, the relationship of ΔX ′, ΔY ′, ΔX1 ′, ΔY1 ′, ΔX2 ′, ΔY2 ′, ΔX3 ′, ΔY3 ′ indicates the position correction amount of the adjacent image. In step S16, a comparative inspection image 710 is created from the image sensor inspection images 711 to 714 captured in step S15 by the image processing unit 406.

  The comparison inspection image 710 is compared by the signal processing unit 402 shown in FIG. 11, and foreign matter, defect A, and defect B are detected from the image comparison inspection result 720 shown in FIG. As step S17, the detection result of step S16 is displayed on the display unit 403. This method can reduce the image processing time and the number of execution steps in the first embodiment.

  As an application of the present invention, a usage method combining the first embodiment and the second embodiment may be used. For example, a method of correcting the positional deviation amount of the X stage 302 by the image processing of the first embodiment and correcting the positional deviation amount of the Y stage 301 in the image sensor imaging range of the second embodiment may be used.

  Alternatively, a method may be used in which the positional deviation amount of the X stage 302 is corrected in the image sensor imaging range of the second embodiment, and the positional deviation amount of the Y stage 301 is corrected by the image processing of the first embodiment.

  In other words, the application example in which the first embodiment and the second embodiment are combined is, in other words, an inspection method in which an object to be inspected mounted on a stage that moves the X-axis / Y-axis coordinates vertically and horizontally is imaged by an image sensor. The amount of positional deviation between the target position and the actual position of the stage moving toward photographing is obtained on the coordinates, and the orientation of the image sensor with respect to the object to be inspected is adjusted to match the amount of positional deviation on one axis side on the coordinates. When the image is cut out from the shooting range of the shot target position after correction, the cut-out position is corrected in accordance with the position shift amount for the other axis side on the coordinates.

  In this application example, since the image cut-out position correction can be expected to have a higher correction accuracy than the image sensor orientation adjustment correction, the selection should be made as necessary.

  As a further application example, the image sensor orientation adjustment correction and the image cutout position correction can be performed on the one axis side on the coordinates, and the correction on the other axis side can be covered by stage position correction control. . For example, when the frequency of moving operations in the Y-axis direction is low, highly accurate position correction control is used on the Y-axis side.

  Embodiments relating to imaging range control and image sensor position control according to the present invention will be described with reference to FIGS. 6 to 9, 11, 12, and 16 to 19.

  The purpose of this embodiment is to calculate the amount of positional deviation (difference) with respect to the target position of the stage from each image image captured by the image sensor obtained from the actual inspection operation, and to set an arbitrary amount for the calculated stage position deviation amount. By selecting the threshold setting and the position deviation correction method, the optimal position correction control according to the stage performance is performed, and the effect equivalent to or higher than that of the high-precision stage inspection is obtained despite the low cost. It is.

  Since FIG. 6 to FIG. 9 are described in the first embodiment, description thereof is omitted.

  Since FIGS. 11 and 12 are described in the second embodiment, description thereof is omitted.

  16 to 18 are flowcharts of the present embodiment.

  FIG. 19 is a diagram illustrating the amount of positional deviation of each of the image images 801 to 804 in the imaging range 800 during the inspection operation.

  Hereinafter, this embodiment will be described in detail with reference to the flowchart of FIG.

  In step S21, the inspected substrate 1 is set on the stage unit 300 shown in FIG. In step S22, the X stage 302 and Y stage 301 shown in FIG. 11 are inspected, and the image sensor 800 captures the image 800 of the substrate 1 to be inspected shown in FIG.

  In the image 800, 801 is referred to as a reference image, and 801 to 804 are referred to as comparative images.

  In step S23, the pixel No. of an arbitrary reference pattern projected on the reference image 801 of the image image 800 shown in FIG. (Xp1, Yp1) and reference pattern pixel Nos. Projected on the comparison images 802 to 804. The amount of stage displacement (ΔXp, ΔYp) is calculated from the amount of image position deviation by comparing (Xp2, Yp2), (Xp3, Yp3), (Xp4, Yp4). An example of the calculation formula is shown below.

(Example)
Misalignment amount (difference) of the X stage 302: ΔXp
ΔXp = [(Xp1) − (Xp2)] × pixel size × magnification (Equation 1)
Amount of displacement (difference) of Y stage 301: ΔYp
ΔYp = [(Yp1) − (Yp2)] × pixel size × magnification (Equation 2)
In step S24, the stage position deviation amount calculated in step 23, the correction method selection screen for the stage position deviation amount, and the threshold setting screen are displayed on the display unit 403 shown in FIG.

  In step 25, a threshold value and a correction method are selected. The threshold value can be arbitrarily set according to the stage position deviation amount.

  Further, in accordance with the amount of stage displacement, the position correction method based on the inspection image cutout range shown in steps S4 to S8 in FIGS. 10 and 14 and the position correction by the image sensor shown in steps S14 to S17 in FIGS. The method can be arbitrarily set according to the stage position deviation amount and the operation frequency of the stage drive shaft.

  For example, when using a relatively high-accuracy stage with a small amount of positional deviation, the position of the image sensor driving unit can be reduced and the cost can be reduced by correcting the position within the image cutout range. Further, when using a stage with a large amount of positional deviation, the position can be corrected to a range that cannot be corrected by the image cutout range by correcting the position by the image sensor.

  Further, as shown in FIGS. 17 and 18, the correction method of the stage position deviation amount may be determined without using the threshold setting.

  Further, in this method, the stage accuracy can be varied by variably setting the magnification of the zoom lens 204 shown in FIG. 11 according to the high sensitivity specification and high throughput specification of the apparatus. Further, since the position of the stage can be corrected with high accuracy without using a laser length measuring device, the cost of the stage can be reduced.

  As described above, a foreign substance inspection apparatus for a semiconductor substrate (wafer) involved in semiconductor manufacturing is taken as an example, regardless of glass substrates used for liquid crystal panels, ALTIC substrates, sapphire substrates used for sensors, LEDs, etc. Any substrate can be used.

  Further, the present invention is not limited to a semiconductor inspection apparatus, and can be widely applied to various manufacturing processes such as a hard disk, a liquid crystal panel display device, and various sensors.

It is a figure which concerns on Example 1 of this invention and shows the example of the structure of a defect inspection apparatus. FIG. 4 is a diagram illustrating a substrate to be inspected according to Embodiment 1 of the present invention and on which LSIs that are samples to be inspected are arranged. FIG. 4 is a diagram for explaining three inspection illumination lights related to the illumination optical system of the defect inspection apparatus according to the first embodiment of the present invention. It is a figure which concerns on Example 1 of this invention, and shows the optical system containing the illumination lens of the illumination optical system of the defect inspection apparatus by this invention. FIG. 4 is a diagram illustrating a function of an illumination lens of an illumination optical system of a defect inspection apparatus according to Example 1 of the present invention. It is a figure which concerns on Example 1 and Example 2 of this invention, and shows a stage relation. It is a figure which concerns on Example 1 and Example 2 of this invention, and shows a movement distance setting map. It is a movement distance map figure based on Example 1 and Example 2 of this invention. It is a figure which concerns on Example 1 of this invention and shows the other example of the structure of a defect inspection apparatus. FIG. 6 is a diagram related to Example 1 of the present invention and shows an imaging range at the time of inspection, a comparative inspection image after position correction, and an image comparison inspection result. It is a figure which concerns on Example 1 of this invention, and shows the further another example of the structure of a defect inspection apparatus. FIG. 10 is a detailed diagram of an image sensor position correction unit according to the second embodiment of the present invention. FIG. 10 is a diagram related to Example 2 of the present invention and showing an imaging range at the time of inspection, a comparative inspection image after position correction, and an image comparison inspection result. FIG. 6 is a flowchart according to the first embodiment of the present invention. FIG. 10 is a flowchart according to the second embodiment of the present invention. FIG. 10 is a flowchart according to the third embodiment of the present invention. FIG. 10 is a flowchart according to the third embodiment of the present invention. FIG. 10 is a flowchart according to the third embodiment of the present invention. FIG. 10 is a diagram related to Example 3 of the present invention and showing the amount of positional deviation of each image within the imaging range during an inspection operation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Substrate to be inspected (wafer), 1a, 1b ... Substrate to be inspected, 1aa ... Memory LSI chip, 1ab ... Memory cell area chip, 1ac ... Peripheral circuit area, 1ad ... Other area, 1ba ... LSI such as microcomputer, 1bb ... Register group area, 1bc ... memory area, 1bd ... CPU core area, 1be ... input / output area, 3 ... beam spot (illumination area), 4, 5, 6 ... detection area of image sensor, 11-13 ... inspection Illumination light, 100 ... illumination optical system, 110 ... first beam spot imaging unit, 120 ... second beam spot imaging unit, 130 ... third beam spot imaging unit, 200 ... detection optical system, 201 DESCRIPTION OF SYMBOLS ... Detection lens (objective lens), 202 ... Spatial filter, 203 ... Imaging lens, 204 ... Zoom lens group, 205 ... Image sensor, 206 ... Observation optical system, 209 Polarization beam splitter, 210 ... branch detection optical system, 300 ... stage unit, 301 ... Y stage, 302 ... X stage, 303 ... Z stage, 304 ... θ stage, 305 ... stage controller, 310 ... laser length measuring device, 311 ... Beam splitter, 312 ... fixed side mirror, 313 ... fixed side mirror, 314 ... movable side mirror, 320 ... linear scale for stage, 321 ... linear scale for stage, 400 ... control system, 401 ... control CPU unit, 402 ... signal processing 403 ... Display unit 404 ... Input unit 405 ... Storage unit 406 ... Image processing unit 500 ... Image sensor position correction unit 501 ... XY correction mechanism 502 ... X-axis motor 503 ... Y-axis motor 600 ... imaging range, 601 ... inspection image 1, 602 ... inspection image 2, 603 ... inspection image 3, 604 ... Inspection images 4, 610 ... comparative inspection images, 611 ... cut out inspection images 1, 612 ... cut out inspection images 2, 613 ... cut out inspection images 3, 614 ... cut out inspection images 4, 620 ... image comparison inspection results, 700 ... imaging range, 701 ... Inspection image 1, 702 ... Inspection image 2, 703 ... Inspection image 3, 704 ... Inspection image 4, 710 ... Comparison inspection image, 711 ... Image sensor inspection image 1, 712 ... Image sensor inspection image 2, 713 ... Image sensor Inspection image 3, 714 ... Image sensor inspection image 4, 800 ... Imaging range during inspection operation, 801 ... Image image 1, 802 ... Image image 2, 803 ... Image image 3, 804 ... Image image 4.

Claims (12)

In the inspection method of photographing and inspecting the inspection object mounted on the moving stage with an image sensor,
Taking an enlarged image of the inspection object, obtaining an enlarged image,
From the magnified image, obtain the amount of positional deviation between the target position of the moving stage and the actual position,
In photographing at the target position, an angle of the image sensor with respect to the inspection object is changed according to the positional deviation amount, or the image sensor with respect to the inspection object is changed according to the positional deviation amount of the stage. An inspection method characterized in that an inspection is performed by obtaining an image in which the displacement is corrected by moving parallel to the movement direction. The inspection method according to claim 1,
An image for inspection is cut out from the image corrected for the positional deviation amount,
An inspection method comprising performing comparison processing using an image for the inspection. The inspection method according to claim 1,
Depending on the amount of positional deviation,
(1) changing the position of the enlarged image from the positional shift amount, cutting out an image for inspection from the enlarged image whose position has been changed, and performing a comparison process;
(2) The angle of the image sensor with respect to the inspection object is changed according to the displacement amount, or the image sensor with respect to the inspection object is changed with respect to the moving direction of the stage according to the displacement amount. An inspection method that switches between performing an inspection by obtaining an image that is moved in parallel to correct the amount of positional deviation. The inspection method according to claim 1,
The stage has an X stage that moves the X axis coordinate and a Y stage that moves the Y axis coordinate,
An inspection method, wherein the positional deviation amount of the X stage is corrected by image processing, and the positional deviation amount of the Y stage is corrected in an image sensor imaging range. The inspection method according to claim 1,
The stage has an X stage that moves the X axis coordinate and a Y stage that moves the Y axis coordinate,
An inspection method, wherein the positional deviation amount of the X stage is corrected within an image sensor imaging range, and the positional deviation amount of the Y stage is corrected by image processing. The inspection method according to claim 1,
The stage has an X stage that moves the X axis coordinate and a Y stage that moves the Y axis coordinate,
A positional deviation amount between the target position and the actual position of the stage moving toward photographing is obtained on coordinates, and the orientation of the image sensor with respect to the inspection object corresponds to the positional deviation amount on one axis side on the coordinates. An inspection method characterized by performing correction correction and correcting the cutout position in accordance with a positional shift amount corresponding to the other axis side on the coordinates when cutting out an image from the shooting range of the shot target position. In an inspection device that photographs and inspects the object mounted on the moving stage with an image sensor,
Taking an enlarged image of the inspection object, obtaining an enlarged image,
From the magnified image, obtain the amount of positional deviation between the target position of the moving stage and the actual position,
In photographing at the target position, an angle of the image sensor with respect to the inspection object is changed according to the positional deviation amount, or the image sensor with respect to the inspection object is changed according to the positional deviation amount of the stage. An inspection apparatus that performs an inspection by moving in parallel with a moving direction and obtaining an image in which the positional deviation amount is corrected. The inspection apparatus according to claim 7,
An image for inspection is cut out from the image corrected for the positional deviation amount,
An inspection apparatus that performs comparison processing using an image for the inspection. The inspection apparatus according to claim 7,
Depending on the amount of positional deviation,
(1) changing the position of the enlarged image from the positional shift amount, cutting out an image for inspection from the enlarged image whose position has been changed, and performing a comparison process;
(2) The angle of the image sensor with respect to the inspection object is changed according to the displacement amount, or the image sensor with respect to the inspection object is changed with respect to the moving direction of the stage according to the displacement amount. An inspection apparatus that switches between performing an inspection by obtaining an image that has been moved in parallel and corrected for the positional deviation amount. The inspection apparatus according to claim 7,
The stage has an X stage that moves the X axis coordinate and a Y stage that moves the Y axis coordinate,
An inspection apparatus that corrects the positional deviation amount of the X stage by image processing and corrects the positional deviation amount of the Y stage in an image sensor imaging range. The inspection apparatus according to claim 7,
The stage has an X stage that moves the X axis coordinate and a Y stage that moves the Y axis coordinate,
An inspection apparatus, wherein the positional deviation amount of the X stage is corrected within an image sensor imaging range, and the positional deviation amount of the Y stage is corrected by image processing. The inspection apparatus according to claim 7 , wherein
The stage has an X stage that moves the X axis coordinate and a Y stage that moves the Y axis coordinate,
A positional deviation amount between the target position and the actual position of the stage moving toward photographing is obtained on coordinates, and the orientation of the image sensor with respect to the inspection object corresponds to the positional deviation amount on one axis side on the coordinates. An inspection apparatus that performs correction correction and corrects a cutout position in accordance with a position shift amount corresponding to the other axis side on the coordinates when cutting out an image from a shooting range of a shot target position.

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