JP2022155012A - Device and method for inspecting substrate - Google Patents

Abstract

To provide an inspection device for a substrate capable of detecting unevenness of a substrate surface.SOLUTION: An inspection device for a substrate includes: a substrate stage for installing a substrate; a light source for irradiating light relative to a surface of the substrate placed on the substrate stage; and imaging means for imaging the surface of the substrate. The light source irradiates inclined light that monotonously changes along a first direction in parallel to the surface of the substrate relative to the surface of the substrate.SELECTED DRAWING: Figure 1

Description

The present invention relates to a substrate inspection apparatus and a substrate inspection method.

Various types of substrates are used for the manufacture of semiconductor devices, etc. However, depending on the application, the surface of the substrate is required to be smooth. Various considerations were made.

For example, Patent Document 1 discloses a light irradiation unit that irradiates light onto a surface to be inspected of a substrate, an imaging unit that acquires an image of the light irradiation unit reflected on the surface to be inspected, and the substrate or the light irradiation unit. By controlling the position of the moving unit for moving the image of the light irradiation unit reflected on the surface to be inspected, and by scattering the light irradiated from the light irradiation unit at the defect portion of the surface to be inspected, and an inspection unit that inspects the surface to be inspected by detecting the formed image outside the contour line of the image of the light irradiation unit. It is

JP 2016-020824 A

However, in Patent Document 1, the image formed by scattering the light irradiated from the light irradiation section at the defect portion of the inspection surface and formed outside the contour line of the image of the light irradiation section. Therefore, an imaging means capable of acquiring images over a wide range has been required. In addition, no specific means for linking the detected scattered light with the position and size of the defect is disclosed, and it cannot be used as an inspection apparatus for detecting irregularities on the substrate surface.

Therefore, in view of the above-described problems of the prior art, it is an object of one aspect of the present invention to provide a substrate inspection apparatus capable of detecting unevenness on the surface of a substrate.

In order to solve the above problems, according to one aspect of the present invention,
a substrate stage for installing a substrate;
a light source that irradiates light onto the surface of the substrate placed on the substrate stage;
and imaging means for imaging the surface of the substrate,
The light source provides a substrate inspection apparatus that irradiates the surface of the substrate with tilted light that monotonously changes along a first direction parallel to the surface of the substrate.

According to one aspect of the present invention, it is possible to provide a substrate inspection apparatus capable of detecting unevenness on a substrate surface.

1 is a schematic diagram of an inspection apparatus according to an embodiment of the present invention; FIG. Explanatory drawing of an irradiation area. FIG. 4 is an explanatory diagram of an image captured by irradiating the surface of a substrate with oblique light;

Hereinafter, the embodiments for carrying out the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments, and without departing from the scope of the present invention, the following embodiments Various modifications and substitutions can be made.
[Substrate inspection device]
The inventors of the present invention diligently studied a board inspection apparatus capable of detecting unevenness on the board surface. During the study, when a linear light was irradiated onto the surface of the substrate, a bright area reflecting the linear light on the surface of the substrate and a dark area adjacent to the bright area and having a lower brightness than the bright area were observed. We focused on the fact that the contrast of the unevenness of the substrate surface increases in the vicinity of the boundary with the region. Then, an operation of forming a bright region and a dark region on the substrate surface and imaging the vicinity of the boundary between the bright region and the dark region is repeated while changing the position of the bright region. The inventors have found that by stitching the images together, it is possible to obtain an image that clearly shows the unevenness of the substrate surface.

However, when inspecting the unevenness of the entire substrate surface, the position of the bright region is moved from one end along the diameter of the substrate surface to the other end, and the boundary between the bright region and the dark region is detected. I need to take an image. As a result of further studies, the inventors have found that it is possible to inspect the unevenness of the substrate surface while shortening the time required for inspecting the substrate by using the oblique light, and completed the present invention.

Here, FIG. 1 shows a perspective view of a board inspection apparatus 10 according to the present embodiment.

The substrate inspection apparatus 10 of the present embodiment includes a substrate stage 11 on which a substrate is placed, a light source 12 for irradiating the surface of the substrate placed on the substrate stage 11 with light, and an imaging device for imaging the surface of the substrate. means 13;

The light source 12 can irradiate the surface of the substrate with inclined light that monotonically changes along a first direction parallel to the surface of the substrate.

Each member will be described below.
(Substrate stage)
The substrate stage 11 is not particularly limited as long as it is a stage on which a substrate to be inspected can be placed.

However, for example, when the substrate side is moved in order to move the irradiation position of the oblique light by the irradiation position control means, the substrate stage 11 is provided with a moving mechanism so that the substrate placed on the substrate stage 11 can be moved in the horizontal direction. can be set. In addition, for example, means for correcting the tilt of the substrate placed on the substrate stage 11 and leveling the substrate, for example, tilt correcting means to be described later can be provided.

The types of substrates to be inspected by the substrate inspection apparatus of the present embodiment are not particularly limited, and various substrates can be used. However, it is preferable that the substrate can reflect at least part of the light from the light source on the surface of the substrate. Also, the shape of the substrate is not particularly limited, but, for example, a disk-shaped substrate can be used.
(light source)
The light source 12 may be configured to irradiate the surface of the substrate placed on the substrate stage 11 with oblique light, and the specific configuration such as the type of the light source is not particularly limited.

Inclined light will be described with reference to FIG.

FIG. 2 shows the first major surface 20A of the substrate 20 illuminated with oblique light from the light source 12. FIG. An irradiation region 21 is defined as a region irradiated with the oblique light on the first main surface 20A of the substrate 20 . A non-illuminated area 22 is an area other than the illuminated area 21 where the light from the light source 12 is not illuminated.

The oblique light can be light that changes monotonically along the Y-axis direction in FIG. 2, which is the first direction, on the first major surface 20A of the substrate 20 as shown in FIG. The first direction is a predetermined arbitrary direction parallel to the first main surface 20A of the substrate 20, and when the substrate is disk-shaped, the direction along the diameter of the first main surface of the substrate. is preferred.

The oblique light may have a parameter characterizing the light that changes monotonously along the first direction on the surface of the substrate 20, and may be selected from, for example, brightness (brightness), color (chromaticity, saturation), and the like. It can be configured to change one or more types. It is preferable that the slanted light has a brightness, ie a lightness, that changes along the first direction, since it can be particularly easily changed.

It is preferable that the oblique light does not change in the second direction perpendicular to the first direction, ie, the X-axis direction in FIG.

Although the size of the irradiation region 21 irradiated with the oblique light is not particularly limited, it is preferably large from the viewpoint of shortening the time required for inspecting the substrate and improving the productivity of the inspection. For example, in an image obtained by imaging the entire surface of the substrate 20 with the imaging means, the irradiation region 21 irradiated with the oblique light preferably includes 20 pixels or more along the first direction, and more preferably includes 50 pixels or more. The upper limit of the length along the first direction of the irradiation region irradiated with the oblique light in the image obtained by imaging the entire surface of the substrate by the imaging means can be selected according to the size of the substrate, the light source, the imaging means, and the like. Not limited. For example, the entire first main surface 20A of the substrate 20 may be irradiated with the oblique light to form the irradiation region 21. In the image obtained by imaging the entire surface of the substrate by the imaging means, the irradiation region irradiated with the oblique light may be projected in the first direction. The length along can be, for example, 1000 pixels or less. In order to measure the unevenness of the substrate surface with particularly high accuracy, the length along the first direction of the irradiation area irradiated with the oblique light in the image obtained by imaging the entire surface of the substrate by the imaging means should be 100 pixels or less. It is more preferable to have

Note that when the entire surface of the substrate is imaged, the irradiation area 21 preferably falls within the above range when the diameter of the substrate is 1000 pixels along the first direction.

Although the length of the irradiation area 21 in the second direction perpendicular to the first direction, that is, the X-axis direction in FIG. It is preferred to choose its length so that it can be illuminated across and form an illuminated area.

As described above, when a light source irradiates the surface of a substrate with linear light to form a bright region and a dark region, the unevenness of the substrate surface is clearly defined between the bright region and the dark region. can do. By using the tilted light in the substrate inspection apparatus of the present embodiment, a bright region and a dark region, for example, can be continuously formed along the first direction in the irradiated region 21 irradiated with the tilted light on the surface of the substrate. Therefore, in the irradiation region 21 , the contrast of the unevenness of the substrate surface can be increased, and the presence or absence of the unevenness in the entire irradiation region 21 can be inspected based on the captured image of the irradiation region 21 . Therefore, compared to the method of forming a bright region and a dark region on the surface of a substrate using linear light, which the inventor of the present invention discovered, a wider range can be inspected at once. The time required for inspecting the board can be particularly short.

FIG. 3 shows an example in which the substrate surface is irradiated with oblique light. In FIG. 3, the Y-axis direction corresponds to the first direction, and a depression 31 that could not be seen before irradiation with the oblique light can be seen.

As the light emitting means of the light source, it is sufficient to irradiate oblique light, and as the light source, for example, one or more types selected from fluorescent lamps, organic or inorganic electroluminescence lighting (EL lighting) lighting, light emitting diode lighting, etc. can be used. can.

Various displays can also be used as the light source. When a display is used as the light source, it is preferable to display and use an image in which the parameters characterizing the light are monotonously changed along one direction on the display surface of the display.

Also, the wavelength of the light emitted from the light source is not particularly limited as long as at least part of the light is reflected by the surface of the substrate to be evaluated, and the reflected image can be captured by the imaging means 13 . For this reason, the light emitted by the light source may be, for example, infrared light, visible light, or ultraviolet light. Preferably, the light includes visible light.

For example, the light source 12 may be fixed to an arm 16 installed in the board inspection apparatus 10 as shown in FIG. However, it is not limited to such a form, and the light source 12 can also be fixed using a tripod or the like separately from other members.
(imaging means)
The imaging means 13 can image the surface of the substrate. More specifically, the imaging means 13 can capture an image of an irradiation area irradiated from the light source 12 on the surface of the substrate.

The imaging means 13 may image at least a region including, for example, the irradiation region 21 on the main surface of the substrate. Therefore, an imaging region 23 surrounded by a dashed line can be imaged so as to include the irradiation region 21, for example. When an image is taken so as to include the periphery of the irradiation area 21 as in the imaging area 23, an image of the target irradiation area can be cut out from the picked-up image by an image processing means to be described later.

The configuration of the imaging means is not particularly limited as long as it can image the irradiation area formed on the substrate as described above. As the imaging means 13, a camera module having various imaging elements can be used. As the imaging element, for example, one or more types selected from semiconductor imaging elements such as a CMOS (complementary metal oxide semiconductor) sensor and a CCD (Charge Coupled Device) sensor, a phototube, an imaging tube, and the like can be used.

The image captured by the imaging means 13 may be either a moving image or a still image. In the case of a moving image, for example, a plurality of still images of an imaging area at arbitrary timing can be extracted and spliced from the photographed images by image processing means to be described later.

In addition, the imaging means 13 may be a means capable of imaging a linear (strip-shaped) imaging area depending on the shape of the irradiation area and the like, so the imaging means may be a line scan camera, for example. A line scan camera means a camera module in which imaging elements are linearly arranged and capable of imaging a linear (band-shaped) imaging area.

For example, as shown in FIG. 1, the imaging means 13 can be fixed to an arm 16 installed in the board inspection apparatus 10, and the light source 12 is also fixed to the arm 16 as described above. can also However, it is not limited to such a form, and the imaging means 13 can also be fixed using a tripod or the like separately from other members.

The substrate inspection apparatus of the present embodiment can further have arbitrary members other than the substrate stage, the light source, and the imaging means described above.
(Irradiation position control means)
As described above, in the substrate inspection apparatus according to the present embodiment, the imaging unit 13 can image the imaging area including the irradiation area on the substrate surface.

However, when the entire surface of the substrate is to be inspected and the irradiation region cannot be formed on the entire surface of the substrate, it is preferable to repeatedly change the position of the irradiation region and image the imaging region. It is preferable that the change in the irradiation position and the imaging of the imaging area be repeated until an image of the portion to be inspected when the obtained images of the imaging area are joined, for example, an image of the entire substrate surface.

Therefore, the substrate inspection apparatus of the present embodiment can also have irradiation position control means 14 for changing the position of the irradiation area, which is the position where the oblique light is irradiated on the surface of the substrate.

The irradiation position control means 14 can, for example, move the irradiation area in the first direction, ie, the Y-axis direction in FIG. In this case, for example, the irradiation position control means 14 can control the movement of at least one of the substrate stage 11 and the light source 12 .

For example, when the first direction of the irradiation area irradiated by the light source 12 is parallel to the arrow 11A in FIG. 1, the substrate stage 11 is moved in the direction of the arrow 11A in FIG. 1 or in the direction opposite to the arrow 11A. By moving, the substrate placed on the substrate stage 11 can be moved. Thereby, the position of the irradiation region formed on the substrate can be moved in the first direction.

Alternatively, the light source 12 may be fixed to an arm 16, for example, as shown in FIG. 1, as previously described, and the arm 16 may be rotated in the direction of arrow 16A in the figure, or in the direction opposite to arrow 16A. , the irradiation position of the linear light from the light source 12 can be changed. Therefore, the position of the irradiation area can also be moved.

Therefore, for example, at least one member selected from the substrate stage 11 and the arm 16 to which the light source 12 is fixed may be provided with driving means, such as a motor, for moving or rotating each member. The irradiation position control means 14 can be connected to the driving means to control the amount of displacement and the direction of displacement.

Note that when the light source 12 is moved, the imaging means 13 can also be configured to be movable in accordance with the change in the position of the irradiation area.

The moving direction of the irradiation area is not limited to the first direction, and for example, the irradiation area can be configured to rotate along the circumferential direction of the substrate. In this case, driving means such as a motor may be arranged so as to rotate the substrate stage 11 in the horizontal plane, and the irradiation position control means 14 may be connected to the driving means.

By moving the irradiation area formed on the surface of the substrate by the irradiation position control means 14, the imaging area to be imaged by the imaging means 13 is moved. Preferably, an image can be formed, for example an image of the entire substrate surface. For this reason, after forming an irradiation region so as to include a first end, which is, for example, an arbitrary end of the surface of the substrate, the irradiation region is moved along the first direction to the opposite side of the first end, That is, it is preferable to move until the straight line passing through the first end and the center of the substrate includes the second end orthogonal to the end of the substrate, because the substrate surface can be imaged efficiently and without gaps. .

When the irradiation area is moved by the irradiation position control means 14, it is preferable to move the irradiation area after movement so as to be adjacent to the irradiation area before movement. In addition, it is also possible to move so that the irradiation area before movement and the irradiation area after movement partially overlap.
(Image processing means)
The image processing means 15 can process the image captured by the imaging means 13 .

The image processing unit 15 is an ASIC (application specific integrated circuit) or the like, and is in charge of processing the image captured by the imaging unit 13 .

In the image processing means 15, an image of the entire substrate surface is formed by cutting out an image of the irradiation area from the image captured by the imaging means 13 as necessary, arranging the images along the movement direction of the irradiation area, and connecting the images. can be done. At this time, the contrast and the like in the image can be corrected as required.

When the image capturing means 13 captures a moving image, the image processing means 15 can also extract a plurality of still images of the image capturing area at a predetermined timing.

The image created by the image processing means 15 can be output to the output means 17, and unevenness can be visually detected from the obtained image based on the difference in contrast in the obtained image. The configuration of the output means 17 is not particularly limited, and may be, for example, display means such as various displays, or printing means such as a printer.

Further, the image processing means 15 can be equipped with, for example, AI (artificial intelligence), and detects concave portions and convex portions on the substrate surface from the image of the substrate surface obtained as described above, and notifies it. It can also be configured as

The image processing means 15 can be realized by software in one ASIC, but may be partially or wholly realized by hardware, for example, by providing a plurality of ASICs.
(Inclination correction means)
The substrate inspection apparatus of the present embodiment may further include, for example, tilt correction means for horizontalizing the substrate. The tilt correction means is provided, for example, on the substrate stage described above or on the body of the substrate inspection apparatus of the present embodiment, and corrects the tilt so that the surface of the substrate to be inspected is horizontal with respect to the light source. can be configured as

According to the substrate inspection apparatus of the present embodiment described above, it is possible to easily detect unevenness of the substrate surface with a simple apparatus configuration including a light source, an imaging means, and a substrate stage.
[Substrate inspection method]
Next, a substrate inspection method according to the present embodiment will be described. The substrate inspection method of the present embodiment can be preferably carried out using the above-described substrate inspection apparatus. Therefore, a part of the description of the matters that have already been described will be omitted.

The substrate inspection method of the present embodiment can have the following light irradiation process and imaging process.

In the light irradiation step, the surface of the substrate placed on the substrate stage can be irradiated with light from the light source.

In the imaging step, the surface of the substrate can be imaged by the imaging means.

The light source can irradiate the surface of the substrate with oblique light that monotonically changes along a first direction parallel to the surface of the substrate. In addition, the imaging step can capture an image of the area irradiated with the oblique light on the surface of the substrate.

Each step will be described below.
(Light irradiation step)
In the light irradiation step, the surface of the substrate placed on the substrate stage can be irradiated with light from the light source.

Since the light source, the tilted light, etc. have already been described, a detailed description thereof will be omitted. For example, one or more selected from brightness (brightness), color (chromaticity, saturation), etc. can be configured to change. It is preferable that the slanted light has a brightness, ie a lightness, that changes along the first direction, since it can be particularly easily changed.

It is preferable that the oblique light does not change in the second direction perpendicular to the first direction, ie, the X-axis direction in FIG.

Although the size of the irradiation region 21 irradiated with the oblique light is not particularly limited, it is preferably large from the viewpoint of shortening the time required for inspecting the substrate and improving the productivity of the inspection. For example, in an image obtained by imaging the entire surface of the substrate 20 in FIG. 2 with an imaging means, the irradiation region 21 irradiated with the oblique light preferably includes 20 pixels or more along the first direction, and more preferably includes 50 pixels or more. preferable.

Depending on the size of the light source 12 and the substrate 20, the entire first main surface 20A of the substrate 20 may be irradiated with the oblique light to form the irradiation region 21. FIG. The length along the first direction of the irradiation region irradiated with the oblique light in the image obtained by imaging the entire surface of the substrate by the imaging means can be 1000 pixels or less, and more preferably 100 pixels or less.

The length of the irradiation area 21 in the second direction, that is, the X-axis direction in FIG. 2 is not particularly limited. , preferably its length is chosen so as to form an illuminated area.

The light emitting means of the light source may irradiate oblique light, and the light source may be one or more selected from, for example, fluorescent lamps, organic or inorganic electroluminescence lighting (EL lighting), light-emitting diode lighting, and the like.

Various displays can also be used as the light source. When a display is used as the light source, it is preferable to display and use an image in which the parameters characterizing the light are monotonously changed along one direction on the display surface of the display.

In the irradiation position moving step, which will be described later, by moving the irradiation area formed on the surface of the substrate, the imaging area to be imaged by the imaging means is moved, and when the images obtained by imaging the imaging areas are joined, the part to be inspected is changed. Preferably, an image can be formed, for example an image of the entire substrate surface. For this reason, for example, in the light irradiation step, it is preferable to first irradiate light from the light source so that the irradiation region can be formed so as to include the first end, which is an arbitrary end of the surface of the substrate. Then, in the irradiation position moving step, which will be described later, the irradiation area is moved along the first direction to the opposite side of the first end, that is, the straight line passing through the first end and the center of the substrate is the end of the substrate. Since the substrate surface can be imaged efficiently and without gaps, it is preferable to move the substrate until it includes the second end orthogonal to .
(Imaging process)
In the imaging step, the surface of the substrate placed on the substrate stage can be imaged. In the imaging step, more specifically, an image of the irradiated area irradiated from the light source 12 on the surface of the substrate can be imaged. In the imaging step, an image of at least a region including, for example, the irradiation region 21 may be captured on the main surface of the substrate. Therefore, an imaging region 23 surrounded by a dashed line in FIG. 2 can be imaged so as to include the irradiation region 21, for example. When an image is taken so as to include the periphery of the irradiation area 21 as in the imaging area 23, an image of the target irradiation area can be cut out from the picked-up image by an image processing means to be described later.

In the imaging process, for example, the irradiation area may be imaged, and depending on the shape of the irradiation area, the necessary image may be a linear (strip-shaped) image. Therefore, a line scan camera can also be used as the imaging means.

The substrate inspection method of the present embodiment may further include optional steps as required.
(Irradiation position moving step)
In the irradiation position moving step, the position of the substrate surface irradiated with the oblique light, that is, the position of the irradiation region can be moved. For example, as described above, the position of the irradiation area can be moved by the irradiation position control means.

For example, as described above, at least one of the substrate stage 11 on which the substrate is placed and the light source 12 can be moved.

In the irradiation position moving step, the irradiation area may be moved continuously or may be moved intermittently. For example, it is possible to select the movement condition of the irradiation area according to the performance of the imaging means.

Continuously moving the irradiation region means, for example, continuously moving the irradiation region without stopping, including repeating steps described later. In this case, in the imaging process in the repeating process described later, the imaging area can be imaged at arbitrary timing and intervals.

Further, when the irradiation region is intermittently moved, the irradiation position moving step and the imaging step can be alternately performed in the repeating step described later. That is, in the irradiation position moving step, the irradiation region is moved by a certain distance, stopped, and then the imaging step is performed. After the irradiation position moving step is performed again, the imaging step can be performed.

The moving speed of the irradiation area in the irradiation position moving step or the moving distance of one time is not particularly limited, and can be arbitrarily selected based on the size of unevenness on the substrate surface to be detected, the efficiency of inspection, and the like.

In the irradiation position moving step, when moving the irradiation region, it is preferable to move the irradiation region after movement so as to be adjacent to the irradiation region before movement. In addition, it is also possible to move so that the irradiation area before movement and the irradiation area after movement partially overlap.
(Repeated process)
In the repeating process, the imaging process and the irradiation position moving process can be repeatedly performed. Accordingly, it is possible to acquire images of a plurality of imaging regions along the moving direction of the irradiation region.

In the substrate inspection method of the present embodiment, by moving the irradiation area formed on the surface of the substrate, the imaging area to be imaged by the imaging means is moved, and the inspection is performed when the images obtained by imaging the imaging areas are joined together. It is preferable to be able to image a portion, for example an image of the entire substrate surface. For this reason, it is preferable to combine the obtained images of a plurality of imaging areas in the repeated process so as to obtain an image of a portion to be inspected, for example, an image of the entire substrate surface.

Also in the repeating process, the imaging process and the irradiation position moving process can be carried out according to the procedure described above, so the description is omitted here.
(Image processing step)
In the image processing step, the image obtained in the imaging step can be processed.

Specifically, for example, from the images captured in the imaging process in the imaging process and the repeated process, the irradiation area is cut out as necessary, arranged along the moving direction of the irradiation area, and joined to form an image of the entire substrate surface. can be At this time, the contrast and the like in the image can be corrected as required.

Further, when a moving image is captured in the imaging process, a plurality of still images of the imaging area can be extracted at a predetermined timing in the image processing process.

The image processing process allows the unevenness of the substrate surface to be visually confirmed from the contrast with other portions.

Therefore, the unevenness of the substrate surface can be detected by outputting an image obtained in the image processing step to an output device and performing visual observation or image processing.

Further, in the image processing step, for example, AI (artificial intelligence) may be used to detect recesses and protrusions on the substrate surface from the image of the substrate surface obtained as described above, and notify the user. can.
(Tilt correction process)
The substrate inspection method of the present embodiment can further include an inclination correction step of leveling the substrate placed on the substrate stage.

A specific method for adjusting the horizontality of the substrate is not particularly limited. can be adjusted.

Further, when the unevenness formed on the substrate surface is the same as the first direction of the irradiation area, such unevenness may not be detected.

Therefore, in the substrate inspection method of the present embodiment, after performing the light irradiation process and the imaging process, the substrate can be rotated by an angle of less than 180 degrees along the circumferential direction and inspected again (reinspection). process).

By rotating the substrate in this manner and performing the inspection a plurality of times, the unevenness of the substrate surface can be detected more reliably, which is preferable.

The angle of rotation of the substrate may be greater than 0 degrees and less than 180 degrees. is preferably

Moreover, when performing the second inspection, it is preferable to perform the inspection under the same conditions as the first time, except that the substrate is rotated before the inspection.

According to the substrate inspection method of the present embodiment described above, it is possible to easily detect unevenness of the substrate surface with a simple device configuration including a light source, an imaging means, and a substrate stage.

10 Substrate inspection device 11 Substrate stage 12 Light source 13 Imaging means 14 Irradiation position control means 15 Image processing means 20 Substrate

Claims (12)

a substrate stage for installing a substrate;
a light source that irradiates light onto the surface of the substrate placed on the substrate stage;
and imaging means for imaging the surface of the substrate,
The substrate inspection apparatus, wherein the light source irradiates the surface of the substrate with inclined light that monotonously changes along a first direction parallel to the surface of the substrate. 2. The substrate inspection apparatus according to claim 1, wherein an image obtained by imaging the entire surface of the substrate by the imaging means includes 20 or more pixels along the first direction in the area irradiated with the oblique light. 3. The substrate inspection apparatus according to claim 1, further comprising irradiation position control means for changing a position of irradiation of the oblique light on the surface of the substrate. 4. The substrate inspection apparatus according to claim 1, wherein the oblique light has a brightness that changes along the first direction. 5. The board inspection apparatus according to claim 1, wherein the light source is one or more selected from fluorescent lamps, electroluminescence lighting, and light emitting diode lighting. 6. The substrate inspection apparatus according to any one of claims 1 to 5, further comprising tilt correction means for horizontalizing the substrate. a light irradiation step of irradiating the surface of the substrate placed on the substrate stage with light from a light source;
an imaging step of imaging the surface of the substrate with imaging means,
the light source irradiates the surface of the substrate with inclined light that monotonously changes along a first direction parallel to the surface of the substrate;
The imaging step is a method of inspecting a substrate for imaging a region irradiated with the oblique light on the surface of the substrate. 8. The substrate inspection method according to claim 7, wherein the image obtained by imaging the entire surface of the substrate by the imaging means in the imaging step includes 20 or more pixels along the first direction in the area irradiated with the oblique light. an irradiation position moving step of moving a position on the surface of the substrate where the inclined light is irradiated;
9. The substrate inspection method according to claim 7, further comprising a repeating step of repeatedly performing the imaging step and the irradiation position moving step. 10. The method of inspecting a substrate according to claim 7, wherein the oblique light changes in brightness along the first direction. 11. The substrate inspection method according to any one of claims 7 to 10, wherein the light source is one or more selected from fluorescent lamps, electroluminescence lighting, and light emitting diode lighting. 12. The substrate inspection method according to any one of claims 7 to 11, further comprising an inclination correcting step for horizontalizing the substrate.

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