JP5245482B2 - Substrate inspection apparatus and mask substrate manufacturing method - Google Patents

Description

  The present invention relates to a substrate inspection apparatus and a method for manufacturing a mask substrate. More specifically, the present invention relates to detection of a scratch on a mask substrate used in a liquid crystal exposure apparatus for manufacturing a device such as a liquid crystal display element in a lithography process.

  There is a demand that a mask substrate (transparent glass substrate on which a transfer pattern is not formed) used in a liquid crystal exposure apparatus should not have any scratches (defects) having a length of about 2 μm, for example. However, it is very difficult to detect a linear (or slit-shaped) scratch formed on the surface of the substrate. This is because not only the contrast of the image formed by the scattered light from the minute linear scratches is low, but also the contrast significantly changes depending on the direction of illumination with respect to the scratches and the direction of observation.

  For this reason, visual inspection using a high-illuminance illumination device is the mainstream, and the current situation is that visual inspection is performed while manually changing the illumination direction and the observation direction with respect to the inspection area of the substrate. Manual visual inspection methods are undesirable from the standpoint of reproducibility and cost. In view of this, a substrate inspection apparatus that irradiates inspection light onto a substrate inspection region from a plurality of directions and observes the forward scattered light from scratches in a dark field has been proposed (see Patent Document 1).

JP-A-4-344447

  In the substrate inspection apparatus disclosed in Patent Document 1, the angles of a plurality of inspection lights with respect to the normal line of the substrate are defined. However, this substrate inspection apparatus cannot reliably detect minute linear scratches extending along all directions.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a substrate inspection apparatus capable of reliably detecting minute linear scratches extending in all directions.

In order to solve the above problems, in the first embodiment of the present invention, in the substrate inspection apparatus for inspecting the foreign matter on the substrate,
An illumination system for illuminating the substrate;
An imaging system for dark field observation of the area on the substrate illuminated by the illumination system;
The illumination system illuminates the area on the substrate with a light beam that moves so as to draw a side surface of a cone with the optical axis of the imaging system as a center.

In the second embodiment of the present invention, in the substrate inspection apparatus for inspecting the foreign matter on the substrate,
An illumination system for illuminating the substrate;
An imaging system for dark field observation of the area on the substrate illuminated by the illumination system;
The imaging system has a single imaging unit,
The single imaging unit rotates and moves around the optical axis of the illumination system so that the optical axis of the single imaging unit describes a side surface of a cone centered on the optical axis of the illumination system. I will provide a.

In the third embodiment of the present invention, in the substrate inspection apparatus for inspecting the foreign matter on the substrate,
An illumination system for illuminating the substrate;
An imaging system for dark field observation of the area on the substrate illuminated by the illumination system;
The imaging system has a plurality of imaging units,
The plurality of imaging units rotate and move integrally around the optical axis of the illumination system so that the optical axis of each imaging unit describes a side surface of a cone centered on the optical axis of the illumination system. A substrate inspection apparatus is provided.

In the fourth embodiment of the present invention, in the method for manufacturing a mask substrate,
Provided is a manufacturing method characterized by including an inspection step of inspecting a foreign substance on the mask substrate using the substrate inspection apparatus according to the first, second or third embodiment.

  In the substrate inspection apparatus of the present invention, for example, a plurality of illumination units are integrally rotated around the optical axis of the imaging system, thereby observing a substrate illuminated with the required multipolar illumination close to the annular illumination for dark field observation. Dark field observation that is optically equivalent to this is performed. As a result, illumination light is irradiated from various angular directions to linear scratches in the illumination area of the substrate, and scattered light generated from the linear scratches is two-dimensionally distributed in various angular directions. Spread and reliably detected by the imaging system. Thus, the substrate inspection apparatus of the present invention can reliably detect minute line-shaped scratches extending along all directions.

  Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram schematically showing a configuration of a substrate inspection apparatus according to a first embodiment of the present invention. FIG. 2 is a diagram schematically showing an internal configuration of each lighting unit in FIG. 1. In the first embodiment, the present invention is applied to a substrate inspection apparatus that inspects a scratch on a mask substrate (hereinafter simply referred to as “substrate”) used in a liquid crystal exposure apparatus.

  Referring to FIG. 1, a substrate inspection apparatus according to the first embodiment includes an illumination system 1 that illuminates a substrate 30 to be inspected, and an imaging system 2 that performs dark field observation of a region on the substrate 30 illuminated by the illumination system 1. And. The illumination system 1 includes, for example, two illumination units 1a and 1b and a drive unit 1k that integrally rotates these illumination units 1a and 1b around the optical axis AX2 of the imaging system 2.

  As shown in FIG. 2, each of the illumination units 1a and 1b includes, for example, a halogen lamp 11 as a light source that supplies illumination light (inspection light). The halogen lamp 11 is disposed at the first focal position of the elliptical mirror 12. The light from the halogen lamp 11 is reflected by the elliptical mirror 12 and then forms a light source image at the second focal position of the elliptical mirror 12. Light from this light source image is condensed by a condensing optical system 13 such as a collimator lens, and illuminates the substrate 30.

  FIG. 3 is a diagram schematically showing the positional relationship between the two illumination units viewed along the optical axis of the imaging system and the integral rotational movement of the two illumination units. In FIG. 3, two lighting units 1a and 1b are represented by circles 31a and 31b for easy understanding of the description. Referring to FIG. 3, the two illumination units 1a and 1b sandwich the optical axis AX2 on the outer circumferential circle 31 of the bottom surface of the cone centered on the optical axis AX2 of the imaging system 2 (a plane orthogonal to the optical axis AX2). It is arranged at a symmetrical position.

  In the first embodiment, the two illumination units 1a and 1b rotate and move along a circle 31 centered on the optical axis AX2 while maintaining the positional relationship by the action of the drive unit 1k. In other words, the two illumination units 1a and 1b integrally rotate around the optical axis AX2 so that the optical axis AX1 describes the side surface of the cone having the optical axis AX2 of the imaging system 2 as the center. As a result, the illumination system 1 including the two illumination units 1a and 1b illuminates a specific region on the substrate 30 with a light beam that moves so as to draw a side surface of a cone with the optical axis AX2 of the imaging system 2 as the center.

  The imaging system 2 can perform dark field observation of the illumination area on the substrate 30 so that the zero-order light supplied from the two illumination units 1a and 1b and transmitted through the substrate 30 is not directly received. Is arranged. As the imaging system 2, for example, a CCD camera can be used. However, various forms of the configuration of the imaging system 2 are possible. For example, an imaging system can be configured by an imaging element other than a CCD and an imaging optical system.

  In the first embodiment, while the two illumination units 1a and 1b have reached the required rotation angle position while integrally rotating the two illumination units 1a and 1b around the optical axis AX2 of the imaging system 2, The imaging system 2 performs dark field observation (dark field imaging) of the illumination area on the substrate 30. Specifically, dark field imaging is performed while the two illumination units 1a and 1b are stopped while the two illumination units 1a and 1b are step-rotated and driven at predetermined rotation angles. Alternatively, dark field imaging is performed at the moment when the two illumination units 1a and 1b reach a required rotation angle position while continuously rotating and driving the two illumination units 1a and 1b at a predetermined speed.

  Hereinafter, in order to facilitate understanding of the operational effects of the first embodiment, the two lighting units 1a and 1b are rotated step by step at a rotation angle of 60 degrees, while the two lighting units 1a and 1b are in a stopped state. Consider the case of visual field imaging. In this case, in FIG. 3, when the two lighting units 1a and 1b are rotated by 60 degrees clockwise from the positions of the circles 31a and 31b indicated by solid lines in the drawing, the two lighting units 1a and 1b are shown in FIG. It moves to the position of the circles 32a and 32b indicated by the middle broken line.

  Further, when the two lighting units 1a and 1b are rotated by 60 degrees clockwise from the positions of the circles 32a and 32b indicated by the broken lines in the drawing, the two lighting units 1a and 1b are circles indicated by the broken lines in the drawing. It moves to the position of 33a, 33b. In the first embodiment, a first dark field imaging is performed in a first stop state in which two illumination units 1a and 1b are located at circles 31a and 31b indicated by solid lines in the drawing, and circles 32a and d indicated by broken lines in the drawing are shown. The second dark field imaging is performed in the second stop state moved to the position 32b, and the third dark field imaging is performed in the third stop state moved to the positions of the circles 33a and 33b indicated by broken lines in the drawing.

  This is a six-pole illumination by a total of six illumination units at the positions of a pair of circles 31a, 31b indicated by solid lines in the figure and the positions of four circles 32a, 32b, 33a, 33b indicated by broken lines in the figure. This is optically equivalent to observing the illumination area on the substrate 30 with the imaging system 2 in the dark field. Further, if necessary, by setting the unit rotation angle of the two illumination units 1a and 1b to be smaller than 60 degrees, the substrate 30 can be used for multi-pole illumination (e.g., 8-pole illumination, 10-pole illumination) closer to the annular illumination. It is also possible to illuminate.

  As described above, in the first embodiment, the two illumination units 1a and 1b are integrally rotated around the optical axis AX2 of the imaging system 2 so as to be illuminated with the required multipole illumination close to the annular illumination. Dark field observation optically equivalent to the dark field observation of the substrate 30 is performed. As a result, the illumination light is irradiated to the linear scratch in the illumination region of the substrate 30 from various angular directions, and the transmitted scattered light (diffracted light) generated from the linear scratch has various angles. It is two-dimensionally spread in the direction and is reliably detected by the imaging system 2. That is, in the substrate inspection apparatus according to the first embodiment, it is possible to reliably detect minute linear scratches extending along all directions.

  In the first embodiment, dark field imaging is performed for each rotation angle position of 60 degrees while the two illumination units 1a and 1b are integrally rotated around the optical axis AX2 of the imaging system 2. However, the present invention is not limited to this, and various forms are possible with respect to the number of lighting units, arrangement (positional relationship between a plurality of lighting units), unit rotation angle, and the like. For example, dark field imaging similar to that of the first embodiment can be performed by performing dark field imaging in six stop states while driving a single illumination unit stepwise for every rotation angle of 60 degrees. In this case, the single illumination unit rotates around the optical axis AX2 so that the optical axis of the single illumination unit describes the side surface of the cone having the optical axis AX2 of the imaging system 2 as the center.

  Further, for example, by performing dark field imaging in two stopped states while three-unit illumination units arranged at positions indicated by circles 31a, 33a, and 32b in FIG. Dark field imaging similar to that of the embodiment can also be performed. In this case, the three illumination units rotate and move integrally around the optical axis AX2 so that the optical axis of each illumination unit describes the side surface of the cone having the optical axis AX2 of the imaging system 2 as the center. Thus, when the unit rotation angle is 60 degrees, six dark field imagings are performed in the case of a single lighting unit, and three dark field imagings are performed in the case of two lighting units. In the case of a unit, two dark field imagings are required.

  That is, compared to the case where the illumination system is configured with a single illumination unit, the number of times of dark field imaging is reduced to ½ when the illumination system is configured with two illumination units. When the illumination system is configured, the number of dark field imaging is reduced to 1/3. At this time, assuming that the inspection time is substantially proportional to the number of dark field imaging, the inspection time is reduced to about 1/2 in the case of two illumination units as compared to the case of a single illumination unit. In the case of three lighting units, the inspection time is reduced to about 1/3.

  More generally, when the illumination system is configured with n illumination units, the inspection time can be reduced to about 1 / n compared to the case where the illumination system is configured with a single illumination unit. It will be possible. Since the plurality of illumination units integrally rotate around the optical axis AX2 of the imaging system 2, no interference of optical paths or components occurs in principle between two adjacent illumination units. Note that the number of illumination units is determined in connection with shortening of the inspection time. However, if the number of illumination units increases, the background of the field of view of the imaging system 2 becomes too bright, which prevents good dark field observation. Cost.

  Regarding the positional relationship between the plurality of lighting units, it is preferable to arrange the plurality of lighting units at equiangular intervals along the rotational movement direction from the viewpoint of the balance of the apparatus and the efficiency of inspection. However, the present invention is not limited to this. For example, in the two stopped states, two illumination units arranged adjacent to the positions indicated by circles 31a and 32a in FIG. 3 are rotated stepwise at a rotation angle of 120 degrees. By performing dark field imaging, dark field imaging similar to that of the first embodiment can also be performed.

  In FIG. 1, the optical axis AX2 of the imaging system 2 is tilted by a required angle with respect to the normal direction of the substrate 30 so that the imaging system 2 does not capture the imaging system 2 itself reflected by the substrate 30. ing. In addition, in order to perform better dark field observation, it is necessary to prevent peripheral members from entering the transmission field background on the illumination system side of the substrate 30 and the reflection field background on the imaging system side of the substrate 30 as much as possible. .

  In the above description, dark field imaging is performed for each predetermined rotation angle position while rotating one or more illumination units around the optical axis of the imaging system. However, the present invention is not limited to this, and an imaging system is configured with one or a plurality of movable imaging units, an illumination system is configured with one fixed illumination unit, and one or more imaging units are illuminated. Dark field imaging similar to that of the first embodiment can also be performed by performing dark field imaging for each predetermined rotation angle position while rotating around the optical axis of the system.

  Specifically, when an imaging system is configured with a single imaging unit, the single imaging unit has an optical axis of the illumination system such that the optical axis describes the side of the cone centered on the optical axis of the illumination system. Rotate around the center. In addition, when an imaging system is configured with a plurality of imaging units, the plurality of imaging units have the illumination system optical axis so that the optical axis of each imaging unit draws a side surface of a cone centering on the optical axis of the illumination system. Rotate and move as a center. However, when one or more imaging units are rotated around the optical axis of the illumination system, the field of view on the substrate changes, so from the viewpoint of image processing, one or more illumination units are moved around the optical axis of the imaging system. It is more desirable to rotate it.

  By the way, the outer shape of the illumination area formed on the substrate, that is, the shape of the aperture (light passage portion) of the field stop that defines the outer shape of the illumination area on the substrate is used when the end portion of the substrate is to be inspected. This is important when you want to reduce unnecessary background light. For example, in the inspection of a substrate having a rectangular outer shape, if a circular illumination region is formed at the end portion of the substrate, a part of the illumination light is incident on the edge of the substrate, and the influence of scattered light from the edge portion This makes it impossible to perform good dark field observation. In order to perform inspection by good dark field observation up to the end portion of the substrate having a rectangular outer shape, it is desirable to form a rectangular illumination region on the substrate.

  However, in the first embodiment, even if a field stop having a rectangular opening is arranged inside the two illumination units 1a and 1b, the illumination units 1a and 1b with the optical axis AX2 of the imaging system 2 as the center are arranged. Along with the rotational movement, the rectangular illumination area formed on the substrate 30 also rotates. Specifically, as shown in FIG. 4, the illumination unit 1a arranged at a position indicated by a circle 31a in FIG. 3 has a rectangular illumination area (hatched) having a side parallel to one side on the substrate 30. Region) 41a is formed.

  In this case, when the illumination unit 1a is rotated by 60 degrees around the optical axis AX2 from the position indicated by the circle 31a in FIG. 3 to the position indicated by the circle 32a, the illumination area 41b formed on the substrate 30 becomes the original illumination area. 41a is rotated by 60 degrees around its center. Similarly, the illumination area 41c formed on the substrate 30 by the illumination unit 1a reaching the position indicated by the circle 33a in FIG. 3 has a shape obtained by rotating the original illumination area 41a by 120 degrees around its center. In other words, in order to maintain the shape, position, and orientation of the illumination area formed on the substrate 30 in the first embodiment, a field stop having a variable aperture is disposed inside the illumination units 1a and 1b, and illumination is performed. It is necessary to control the shape of the variable opening according to the rotational movement of the units 1a and 1b.

  FIG. 5 is a diagram schematically showing the configuration of the substrate inspection apparatus according to the second embodiment of the present invention. In the second embodiment, as in the first embodiment, the present invention is applied to a substrate inspection apparatus that inspects a scratch on a mask substrate used in a liquid crystal exposure apparatus. In the second embodiment, only the configuration of the illumination system 1 is different from the first embodiment. Therefore, in FIG. 5, the elements having the same functions as those in the first embodiment are denoted by the same reference numerals as those in FIG.

  In the second embodiment, as shown in FIG. 5, the illumination system 1 that illuminates the substrate 30 to be inspected is configured by a single illumination unit 20. The illumination unit 20 includes an illumination unit main body 21, a field stop 22, a pair of reflection mirrors 23 and 24, and a drive unit 25 that integrally rotates the reflection mirrors 23 and 24 around the optical axis AX2 of the imaging system 2. Have The lighting unit body 21 has an internal configuration as shown in FIG.

  That is, the illumination unit main body 21 includes, for example, a halogen lamp as a light source, an elliptical mirror, and a condensing optical system. The field stop 22 has a rectangular opening, restricts the light flux from the illumination unit main body 21, and defines the outer shape of the illumination area formed on the substrate 30 to be rectangular. The first reflecting mirror 23 is disposed on the optical axis AX1 of the illumination system 1 and deflects to reflect a light beam incident along the optical axis AX1 (and thus along the optical axis AX2 of the imaging system 2) via the field stop 22. Functions as a member.

  The second reflecting mirror 24 functions as a deflecting member that reflects the light beam reflected by the first reflecting mirror 23 toward the illumination area on the substrate 30. As described above, the first reflection mirror 23 and the second reflection mirror 24 are integrally rotated about the optical axis AX2 of the imaging system 2 by the action of the drive unit 25. Further, the optical axis AX1 of the illumination system 1 in the optical path from the illumination unit main body 21 to the first reflection mirror 23 coincides with the optical axis AX2 of the imaging system 2.

  Therefore, in the second embodiment, the first optical axis AX1 of the illumination system 1 in the optical path from the second reflecting mirror 24 to the substrate 30 draws the side surface of the cone having the optical axis AX2 of the imaging system 2 as the center. The reflection mirror 23 and the second reflection mirror 24 are integrally rotated around the optical axis AX2. As a result, also in the second embodiment, the illumination system 1 including the single illumination unit 20 is on the substrate 30 by the light flux that moves so as to draw the side surface of the cone with the optical axis AX2 of the imaging system 2 as the center. Illuminate a rectangular area.

  In the second embodiment, dark field imaging is performed in six stop states while the first reflection mirror 23 and the second reflection mirror 24 in the single illumination unit 20 are driven to rotate stepwise at, for example, a rotation angle of 60 degrees. By doing so, dark field imaging similar to that of the first embodiment can be performed. However, in the second embodiment, unlike the first embodiment in which the entire illumination unit rotates, the illumination unit main body 21 and the field stop 22 are fixedly arranged, and only the pair of reflection mirrors 23 and 24 is the imaging system 2. And rotate around the optical axis AX2.

  Therefore, even if the pair of reflection mirrors 23 and 24 rotate about the optical axis AX2 of the imaging system 2, the rectangular illumination area formed on the substrate 30 does not rotate, and the A rectangular illumination area having sides parallel to one side is formed at the same position and in the same posture. As a result, the substrate inspection apparatus according to the second embodiment can reliably detect minute line-shaped scratches extending in all directions, and can change the edge of the substrate without changing the aperture of the field stop. Inspection by good dark field observation can be performed up to a part.

  In addition, in the configuration in which the reflecting mirror is rotated and moved as in the second embodiment, since the rotating member is small compared to the configuration in which the illumination unit is rotated and moved as in the first embodiment, the illumination is performed at a relatively high speed. The light beam can be rotated. As a result, the measurement time can be shortened, and the throughput (inspection processing capacity) can be improved.

  In each of the above-described embodiments, by rotating the illumination unit or the reflection mirror, it is possible to reliably detect the scratch having the angle dependency of the scattered light, as in the case of the annular illumination. In addition, since the amount of background light is suppressed as compared with the annular illumination, the contrast is higher than in the case of the annular illumination, and it is easy to detect a scratch. This effect is particularly remarkable when the test object is a transparent substrate such as glass.

  In each of the above-described embodiments, the operation of the substrate inspection apparatus according to the present invention has been described focusing on the detection of linear flaws formed on the surface of the substrate. However, in practice, not only linear flaws, but also various other forms of flaws and foreign objects such as various forms of minute objects attached to the substrate can be detected in the same manner. If it is necessary to discriminate scratches formed on the substrate from other foreign matters (such as foreign matter), the image of the substrate surface before cleaning can be compared with the image of the substrate surface after cleaning. good. Further, when the inspection is performed over the entire surface of the substrate or over a wide range, the inspection of the foreign matter may be repeated while relatively moving the substrate to be inspected and the substrate inspection apparatus as the inspection means step by step.

  Further, in each of the above-described embodiments, the present invention is applied to a substrate inspection apparatus that inspects a scratch on a mask substrate used in a liquid crystal exposure apparatus. However, the present invention is not limited to this, and the present invention can be applied to a substrate inspection apparatus that inspects foreign matters on substrates having various forms. That is, the inspection target is not limited to the light transmission type substrate, but may be a reflection type substrate such as a mirror.

  FIG. 6 is a flowchart showing each step of the mask substrate manufacturing method according to each embodiment. Referring to FIG. 6, the method for manufacturing a mask substrate according to each embodiment includes a preparation step S11, a polishing step S12, a cleaning step S13, and an inspection step S14. For example, a material having uniform optical characteristics is required for manufacturing a mask (photomask) substrate used in a liquid crystal exposure apparatus.

  In the preparation step S11, a quartz glass material (ingot) is manufactured by synthesizing quartz as a material having uniform optical characteristics. Specifically, for example, a raw material gas of a silicon compound such as silicon tetrachloride or an organosilicon compound, a combustion-supporting gas such as oxygen, and a gas containing a combustion gas such as hydrogen are ejected from a multi-tube burner to form a flame. A quartz glass material is obtained by reacting in the glass and depositing and melting glass particles on a rotating target.

  As such a method for synthesizing quartz, methods described in JP-A No. 2004-28786, JP-A No. 10-279319, JP-A No. 11-292551, and the like can be used. Further, in the preparation step S11, the quartz glass material is cut into a plate shape. Specifically, a portion to be used as a photomask is cut into, for example, a rectangular plate shape or a disk shape from an ingot created on the target using a band saw or a blade.

  Next, in the polishing step S12, the surface of the plate-like quartz glass cut out through the preparation step S11 is polished by a multi-step process including lapping and polishing. As an apparatus for lapping or polishing the surface of a plate-like quartz glass, a polishing apparatus described in JP 2007-98542 A, JP 2007-98543 A, or the like can be used.

  In the polishing apparatus, a plate-like quartz glass substrate is disposed on a carrier having an opening for holding the outer shape of the plate-like quartz glass. And by sandwiching the top and bottom of the carrier and quartz glass with a surface plate having a polishing surface on the surface in contact with the carrier and quartz glass, by rotating the top and bottom surface plates while contacting the polishing surface and the surface of the quartz glass, Wrapping or polishing. In lapping and polishing, a polishing pad and slurry used for the polishing surface of the surface plate are appropriately selected according to the surface roughness of the quartz glass.

  The fine particles contained in the slurry remain on the surface of the quartz glass substrate that has undergone the polishing step S12. For this reason, in the cleaning step S13, cleaning is performed to remove fine particles adhering to the surface of the quartz glass substrate. Specifically, cleaning can be performed by spraying pressurized water onto the surface of the quartz glass substrate or immersing the quartz glass substrate in a cleaning liquid.

  Lastly, in the inspection step S14, the substrate glass inspection apparatus according to each of the above-described embodiments is used to inspect foreign substances on the quartz glass substrate, particularly scratches on the surface. Specifically, the quartz glass substrate to be inspected is fixedly supported, and the substrate inspection apparatus as the inspection means is stepped two-dimensionally, and foreign matter is inspected over the entire surface of the quartz glass substrate. Do. Alternatively, a foreign substance is inspected over the entire surface of the quartz glass substrate while the substrate inspection apparatus as the inspection means is fixedly supported and the quartz glass substrate to be inspected is stepped two-dimensionally.

  In addition, a large-sized mask substrate can be obtained by press-molding the quartz glass cut into a plate shape in the preparation step S11 to increase the surface area. For press molding, for example, a graphite mold having a flat press surface is prepared, and after being pressurized through the mold in a state of being heated to a temperature higher than the crystallization temperature of quartz glass under an inert gas atmosphere, cooling is performed. Is done. As such a press molding method, a method described in JP-A No. 2004-307266 can be used. The above-described polishing step S12, cleaning step S13, and inspection step S14 are performed on the press-molded quartz glass substrate.

It is a figure showing roughly the composition of the substrate inspection device concerning a 1st embodiment of the present invention. It is a figure which shows schematically the internal structure of each illumination unit of FIG. It is a figure which shows typically the positional relationship of two illumination units seen along the optical axis of an imaging system, and the integral rotational movement of two illumination units. It is a figure which shows a mode that the rectangular-shaped illumination area | region formed on a board | substrate also rotates with rotation movement of an illumination unit in 1st Embodiment. It is a figure which shows schematically the structure of the board | substrate inspection apparatus concerning 2nd Embodiment of this invention. It is a flowchart which shows each process of the manufacturing method of the mask substrate concerning each embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Illumination system 1a, 1b; 20 Illumination unit 1k; 25 Drive part 2 Imaging system 11 Halogen lamp 12 Elliptical mirror 13 Condensing optical system 21 Illumination unit main body 22 Field stop 23, 24 Reflection mirror 30 Substrate

Claims (8)

In a board inspection device that inspects foreign substances on a board,
An illumination system for illuminating the substrate;
An imaging system for dark field observation of the area on the substrate illuminated by the illumination system;
The illumination system illuminates the region on the substrate with a light beam that moves so as to draw a side surface of a cone with the optical axis of the imaging system as a center ,
A substrate inspection apparatus , wherein an optical axis of the imaging system is inclined by a required angle with respect to a normal direction of the substrate. 2. The substrate inspection according to claim 1, wherein a peripheral member does not enter the transmission field background closer to the illumination system than the substrate and the reflection field background closer to the imaging system than the substrate. apparatus. The illumination system has a single illumination unit;
2. The single illumination unit is configured to rotate about the optical axis of the imaging system so that the optical axis of the single illumination unit draws a side surface of a cone centered on the optical axis of the imaging system. Or the board | substrate inspection apparatus of 2. The illumination system has a plurality of illumination units,
The plurality of illumination units rotate and move integrally around the optical axis of the imaging system so that the optical axis of each illumination unit describes a side surface of a cone centered on the optical axis of the imaging system. The substrate inspection apparatus according to claim 1 or 2 . The substrate inspection apparatus according to claim 4 , wherein the plurality of illumination units are arranged at equiangular intervals along the rotational movement direction . The illumination system has a single illumination unit;
The single illumination unit includes a field stop that defines an outer shape of the region on the substrate, a first deflecting member that deflects a light beam incident through the field stop along the optical axis of the imaging system, A second deflection member that deflects the light beam deflected by the first deflection member toward the region on the substrate;
The substrate inspection apparatus according to claim 1, wherein the first deflecting member and the second deflecting member are integrally rotated about the optical axis of the imaging system . The substrate inspection apparatus according to claim 6, wherein the field stop has a rectangular opening . In the mask substrate manufacturing method,
A manufacturing method comprising an inspection step of inspecting foreign matter on the mask substrate using the substrate inspection apparatus according to claim 1 .

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