JPH10148619A - Method and device for inspecting face defect of substrate under inspection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a fine hair-line-like defect with relatively less change in the quantity of light, and at the same time, discriminate whether the defect is located on the front or reverse side by applying, light in straight band shape onto both the front and reverse sides of a substrate to be inspected and detecting scattered light generated from each surface with a CCD camera. SOLUTION: A glass substrate 11 is carried and moved in the direction of an arrow (a) by each carrying roller 22 of a carrying mechanism 21, and light 32a and 32b in straight band shape from light sources 31a and 31b is applied continuously to a specific position of each glass surface of a surface side 12 and a reverse side 13 of the glass substrate 11. A defect detection signal captured by one-dimensional CCD cameras 41a and 41b is processed by corresponding defect signal processors 42a and 42b and then is inputted to a microprocessor 43. The microcomputer 43 performs processing as the amount of feature of each face defect signal, makes comparison along with defect signal position data, judges whether the detected defect is on the surface side 12 or on the reverse side 13, and judges whether the glass substrate 11 is conforming to an inspection standard or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a surface defect inspection method and apparatus for inspecting a substrate, more particularly, for example, a glass substrate which is applied to a liquid crystal display device, the oxide film on the surface (SiO ₂₎ or the transparent conductive One-dimensional CCD (Charge Co.) for inspecting surface defects (especially, flaws called hair lines) on a glass substrate or the like on which a film (ITO) is applied.
upled Device) This relates to an improvement of a method and an apparatus for inspecting a surface defect using a camera.

[0002]

2. Description of the Related Art In general, surface defect inspection of various kinds of products of this kind has been carried out visually, but with the improvement of the performance of the CCD camera, automatic inspection using the CCD camera has been widely performed in various industrial fields. In particular, in the field of liquid crystal display technology, more rigorous and faster product inspection, that is, the liquid crystal display surface is formed here, in accordance with the confirmation of fine hair lines that cannot always be achieved visually. Since it is necessary to perform surface inspection of a glass substrate as a substrate material or a glass substrate having a surface coated with a SiO ₂ film or an ITO film, surface defect inspection using a one-dimensional CCD camera is desired. It is starting to be used.

FIGS. 3 to 5 schematically show a general surface defect inspection apparatus using a conventional one-dimensional CCD camera.

[0004] Examples of ordinary defects include, in addition to the fine scratches such as the hairline described above, for example, adhesion of foreign matter, pinholes, and other scratches. When the (inspection base) is light-transmissive, as shown in FIG. 3, it is obtained by a linear band-shaped irradiation light from the light source 1 under a dark field, for example, a transmission light using a fluorescent lamp or a halogen lamp. A linear band-shaped irradiation light 1a is applied to an inspection object (corresponding to a glass substrate in this case) 2 conveyed in the direction of the arrow and transmitted therethrough, and the transmitted light 1b is linearly arranged orthogonally to the conveyance direction. In the conventional example of FIG. 3, when the irradiation light 1a passes through the inspection target 2, the corresponding transmission surface portion of the inspection target 2 is used. If there is a defect in the Since the amount varies, it is to detect a change in the transmitted light intensity in the one-dimensional CCD camera 3.

When the inspection object 2 is not light-transmitting, as shown in FIG. 4, a similar linear band-shaped irradiation light 4a from the light source 4 is similarly transported in the direction of the arrow. In this case, a one-dimensional CCD camera 6 similarly captures the reflected light 4b by irradiating it at a predetermined incident angle onto a glass substrate 5 whose surface is coated with a SiO ₂ film or an ITO film, and reflecting the reflected light 4b. In the conventional example of FIG.
When the irradiation light 4a is reflected by the surface of the inspection object 5, if there is a defect on the corresponding reflection surface portion of the inspection object 5, the amount of reflected light changes due to the defect. This is detected by the one-dimensional CCD camera 6.

However, in the conventional means shown in FIGS. 3 and 4, all of them are one-dimensional CCD camera 3,
Since the transmitted light 1b or the reflected light 4b is superimposed on the base signal of No. 6, it is impossible to detect a defect with a small change in the amount of light due to a fine flaw defect such as the hairline described above.

As a countermeasure for this, as shown in FIG. 5, a similar linear band irradiation light 7a from a light source 7 is similarly applied to an inspection object (corresponding to a glass substrate) 8 which is conveyed in the direction of the arrow. Irradiation is performed at a predetermined incident angle and reflected, and scattered light 7b generated due to a surface defect of a surface to be irradiated other than direct light or reflected light by the irradiation light 7a is similarly subjected to a one-dimensional CCD.
In the conventional example of FIG. 5, when the irradiation light 7a is reflected on the surface of the inspection object 8, it is determined that a defect exists in the corresponding reflection surface portion of the inspection object 8. The one-dimensional CCD camera 9 detects only the amount of light scattered by the defect.

That is, in the conventional means shown in FIG. 5, neither the transmitted light nor the reflected light is superimposed on the base signal of the one-dimensional CCD camera 9, and only the scattered light 7b is superimposed. It is possible to detect a fine flaw having a small change in the amount of light such as a hairline, for example, a flaw having a width of about 1 μm, and a similarly fine flaw of about 1 μm, which is severe in the field of liquid crystal display technology. It has been put to practical use for the purpose of performing high-speed product inspection based on inspection standards.

[0009]

Here, the inspection standard on the front side of a test substrate as a functional material in various technical fields including the liquid crystal display field is different from that of the back side, Since it is necessary to perform post-processing such as film-coating on the side, the inspection standards tend to be more strict.

In the case of each of the conventional inspection means described above,
If the inspection substrate itself has almost the same aspect on both sides as a glass substrate, for example, and it is relatively difficult to judge the front and back, if a defect of the inspection substrate to be detected exists on the front surface side? It is not easy to distinguish whether it exists on the back side, and even the back side that does not require so strict inspection standards must be inspected under exactly the same strict inspection standards as the front side However, the inspection standard on the back side is too strict, and even if the back side is a good product, it is often determined as a defective product. As a result, the production yield of the entire product may be reduced. was there.

Therefore, recently, when a defect is detected as an inspection of this type of inspection substrate, it is particularly easy to determine whether the defect is a front-side defect or a rear-side defect. There is a need for a proposal of a means that can be inspected by using the method.

Therefore, in order to meet such a demand for clearly separating the front and back of the inspection base, a linear belt-shaped irradiation light is applied at a very shallow incident angle to the detection surface of the inspection base to be transported and moved. And only the reflected light is one-dimensional CC
Means of detecting and detecting with a D camera have been proposed,
In this case, since the irradiation angle is shallow, the detection sensitivity is greatly affected by the warpage of the target test substrate or the vertical vibration associated with the conveyance. If a relatively large test substrate such as a substrate is a target, this means cannot be substantially adopted.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem.
Even a fine defect having a relatively small change in the amount of light, such as a hairline-shaped flaw defect, can be detected, and it is possible to easily determine whether the detected defect is on the front side or the back side. A method and an apparatus for inspecting a surface defect of an inspection base, which can perform a product inspection with a good production yield at high speed and efficiently by applying different inspection standards corresponding to the front side and the rear side, respectively. To provide.

[0014]

According to a first aspect of the present invention, there is provided a method for inspecting a surface defect of an inspection substrate, the method comprising: In the state where the light is irradiated, in addition to the direct light or the reflected light by the irradiation light, the scattered light generated by the surface defect of the irradiation surface is collected and detected by a one-dimensional CCD camera, and the presence or absence of the surface defect of the irradiation surface In the inspection method of detecting the irradiating light in the form of a linear strip on both the front and back surfaces of the inspection substrate, scattered light generated by each surface defect of the irradiated surface on both the front and back surfaces is respectively different from each other. A one-dimensional CCD camera is used to obtain the surface defect detection signals for each of the front and back sides, and the characteristic amount of the front side defect detection signal obtained by the front side one-dimensional CCD camera and the back side surface defect obtained by the back side one-dimensional CCD camera. Comparing the feature quantity of the detection signal, in which the detected surface defect is characterized by determining whether the back side of the surface defect or a surface defect on the surface side.

According to a second aspect of the present invention, there is provided a method of inspecting a surface defect of an inspection substrate according to the first aspect, wherein at least two or more surface defect detection signal characteristic amounts are used to detect a surface defect. It is characterized by determining whether the defect is a surface defect on the side or a surface defect on the back side.

According to a third aspect of the present invention, in the method of inspecting a surface defect of an inspection substrate according to any one of the first and second aspects, the inspection substrate is a light transmitting inspection substrate. It is characterized by the following.

According to a fourth aspect of the present invention, there is provided an apparatus for inspecting a surface defect of an inspection substrate, wherein the surface of the inspection substrate having both front and back surfaces is irradiated with a linear band of irradiation light, and the direct light by the irradiation light is applied. Alternatively, in addition to the reflected light, a one-dimensional CCD camera collects and detects scattered light generated by a surface defect on the irradiated surface, and detects the presence or absence of a surface defect on the irradiated surface. Conveyance means for continuously conveying at a speed, irradiation means for irradiating linear band-shaped irradiation light from a light source at a predetermined incident angle to each specific position on each of the front and back surfaces of the conveyed inspection base, and each irradiation light A one-dimensional CCD camera that captures scattered light generated by a surface defect of each illuminated surface and converts the scattered light into an electric signal, in addition to the direct light or reflected light, and each one detected by the one-dimensional CCD camera. A defect signal processor for processing each surface defect detection signal, and processing each signal processed by each of the defect signal processors to obtain a characteristic amount of the surface defect detection signal. A microcomputer is provided for comparing the characteristic amount of the detection signal with the characteristic amount of the back side surface defect detection signal to determine the front side and the back side of the inspection base.

According to a fifth aspect of the present invention, there is provided an apparatus for inspecting a surface defect of an inspection substrate, wherein the inspection substrate is a light-transmitting inspection substrate. It is.

In the inspection method and apparatus according to the present invention, the detection surfaces on the front and back surfaces of the inspection substrate conveyed by the conveyance mechanism are irradiated with linear band-shaped irradiation light, and the respective scattered lights based on the defects on both front and back surfaces are firstarily scattered. After being captured by the original CCD camera and converted into electric signals, the signals are processed by the corresponding defect signal processors, and the feature values of the respective defect detection signals are compared with each other by the microcomputer. It is easy to determine whether the defect is on the front side or the back side.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the method and apparatus for inspecting a surface defect of an inspection substrate according to the present invention will be described in detail with reference to FIGS. 1 and 2. FIG.

[0021]

FIG. 1 is an explanatory view schematically showing an outline of a surface defect inspection apparatus to which a first embodiment of the method of the present invention is applied.

In the apparatus configuration of the first embodiment shown in FIG. 1, an inspection substrate to be inspected, in this case, a SiO.sub.
The glass substrate 11 for liquid crystal display on which the _two films or the ITO films 11a are adhered is transported by a transport roller 22 constituting the transport mechanism 21 in a transport direction shown by an arrow a at a predetermined transport speed. Here, the glass substrate 11 is made of SiO ₂ film or ITO film 1 for convenience of explanation.
The side on which 1a is attached is referred to as a front side 12 and the opposite side is referred to as a back side 13. Further, in the case of the first embodiment, the transport mechanism 21 can also be transported in the opposite direction indicated by the arrow b at the same transport speed.

The glass substrate 11 conveyed with any surface upward or downward by each of the conveyance rollers 22 of the conveyance mechanism 21 has a specific position on the upper surface where the conveyance moves under a dark field. For example, a linear band-shaped irradiation light 32 from a light source 31 using a lamp such as a halogen or a metal halide can be irradiated at a relatively deep incident angle, and the reflected light 33 of the irradiation light 32 is directly reflected. The scattered light 34 due to the flaw 14 that may be present on the irradiated upper surface is captured by the one-dimensional CCD camera 41 that is located at an upper position that cannot be captured and that is disposed orthogonal to the transport direction. A defect signal processor 42 for processing the converted electric signal to output a surface defect detection signal, and an arithmetic processing unit for discriminating each input signal The microcomputer 43 of the to
Are provided. In the figure, reference numeral 15 denotes a flaw that may be present on the lower surface. The light source 12 for obtaining the linear band-shaped irradiation light 32 may be a linear light source, for example, a point light source. A configuration in which an optical fiber that is focused on the side where the light beam from the shape light source is incident and that is developed linearly on the side where the light beam is emitted is used as light guide, and a rod lens is disposed on the output side.

Therefore, in the device configuration according to the first embodiment,
A defect inspection of the glass substrate 11 as an inspection base is performed as follows.

First, the glass substrate 11 is transported by the transport rollers 22 of the transport mechanism 21 at a predetermined transport speed in the transport direction of arrow a, and the glass substrate 11 is turned upward in a dark field. A specific position on one of the glass surfaces, for example, a specific position on the front side 12 in this case, is continuously irradiated with the linear band-shaped irradiation light 32 from the light source 31. At this time, if there is no scratch defect on the front side 12 which is the upward surface, the irradiation light 32 is reflected as it is and becomes reflected light 33, and if the scratch defect exists, it becomes scattered light 34. Here, the one-dimensional CCD camera 4
Reference numeral 1 denotes a scattered light 34 other than the reflected light 32, which is converted into an electric signal. The converted signal is processed by a defect signal processor 42, and a surface defect detection signal, here, a defect existing position on the front side 12 is provided. The feature amount of the surface defect detection signal including the data is detected and input to the microcomputer 43.

Subsequently, the glass substrate 11 on which the one surface, the front surface 12 has been inspected, is inverted manually or by a handling robot or the like. That is, this time, the rear surface 13 is turned upward and transported in the direction opposite to the arrow b. By doing so, a similar inspection is performed, and similarly, the characteristic amount of the surface defect detection signal including the defect existing position data on the back surface 13 is detected and input to the microcomputer 43.

The microcomputer 43 derives the front side 12 and the back side 13 from these input signal data.
By comparing the feature amounts of the respective surface defect detection signals with each other, it is determined whether the detected flaw defect is a defect on the front side 12 or a defect on the back side 13. According to this, the quality of the glass substrate 11 is determined in accordance with each inspection standard of the front side 12 or the rear side 13, and according to this determination, the front side inspection standard is Since the back side inspection standard can be applied to each side 13, disadvantages such as the above-described conventional method can be easily eliminated.

Incidentally, a halogen lamp is used as the light source 31 and the glass substrate 1 having a size of 360 mm × 460 mm is used.
The detection threshold is set to 4 by the sample which is a typical defect in 1
0 mV, and various other detection conditions were tested.
When the peak signal intensity, which is one of the features of the surface defect signal, was measured, the results shown in Table 1 below were obtained. That is, from this result, for the defects on the front side 12, the peak signal intensity on the front side is all large, and for the defects on the rear side 13, the peak signal intensity on the rear side is all large. It was confirmed that the determination could be made.

[0029]

[Table 1]

[0030]

Embodiment 2 FIG. 2 is an explanatory view schematically showing the outline of a surface defect inspection apparatus to which a second embodiment of the method of the present invention is applied.

In the apparatus configuration of the second embodiment shown in FIG. 2, a glass substrate 11 having an SiO ₂ film or an ITO film 11a adhered to the surface of an inspection substrate to be inspected is also provided.
Is indicated by an arrow a by each transport roller 22 of the transport mechanism 21.
Are transported at a predetermined transport speed only in the transport direction shown in FIG. The glass substrate 11 transported by each transport roller 22 has a front side 1 that is transported and moved under a dark field.
2 and the rear surface 13 (here, for convenience of description, the front surface 12 is the upper surface and the rear surface 13 is the lower surface), and the light sources 31a,
The irradiation light 32a, 32b in the form of a straight band from the irradiation light 31b can be irradiated at a relatively deep incident angle, and the irradiation light 32
The one-dimensional CCD cameras 41a, 41b arranged at respective upper and lower positions that do not directly capture the reflected light 33a, 33b of the a, 32b. Each scattered light 34 a, 3 due to flaws 14 and 15 that may be present on the side 13
4b, each of which converts the converted electric signal into an electric signal, processes the converted electric signal and outputs a surface defect detection signal, and outputs each of the defect signal processors 42a, 42b; Microcomputer 4 as an arithmetic processing unit for discriminating between input signals from input terminal 42b
3 is provided.

Therefore, in the device configuration according to the second embodiment,
A defect inspection of the glass substrate 11 as an inspection base is performed as follows.

First, the glass substrate 11 is transported by the transport rollers 22 of the transport mechanism 21 at a predetermined transport speed in the transport direction indicated by the arrow a, and the glass substrate 11 is turned upward in a dark field. The specific position of each glass surface of the front side 12 and the back side 13 facing downward is determined by the light source 3.
Linear irradiation light beams 32a, 32a from 1a and 31b
Irradiation is successively performed at b. In this case, the irradiation by each of the irradiation lights 32a and 32b does not necessarily have to be performed on the same specific position area on the upper and lower sides of the glass substrate 11, and in order to avoid mutual interference, each irradiation area and each primary It is also preferable to set the inspection areas of the original CCD cameras 41a and 41b so as to be shifted from each other.

Next, each of the one-dimensional CCD cameras 41
The respective defect detection signals caught by the a and 41b are respectively processed by the corresponding defect signal processors 42a and 42b, and then input to the common microcomputer 43, where the characteristic amount of each surface defect signal (for example, , Peak signal strength, area, integrated signal strength, etc.)
The defect is compared with the defect detection position data. Here, similarly to the case of the previous example, it is determined whether the detected flaw is a defect on the front side 12 or a defect on the rear side 13. In accordance with the results, the quality or defect of the glass substrate 11 is determined according to each inspection standard of the front side 12 or the back side 13.
2 can be applied to the front side inspection standard and the back side 13 can be applied to the rear side inspection standard, so that the disadvantages of the above-described conventional method can be easily eliminated. In addition,
The respective defect signal detection conditions by the respective defect signal processors 42a and 42b do not necessarily have to be the same, and different detection conditions based on the respective inspection standards of the front side 12 and the back side 13 may be used. May be adopted.

Here, a halogen lamp is used as each of the light sources 31a and 31b, and the detection threshold is 40 mV, the transport speed is 1 m / min, and the signals of the defect signal processors 42a and 42b are applied to the glass substrate 11 of 360 mm × 460 mm size. The test was performed with the gain, which is the amplification degree, set to 1 and 2 times. As a result, as a typical example of the hairline-shaped flaw defect, a critical defect sample of about 1 μm
Width, about 49μm which is a normal defect sample on the front side 12
Width, and about 10 which is a normal defect sample on the back side 13
The results shown in the following Table 2 were obtained for each scratch defect having a width of 0 μm. That is, from this result, if the gain is 1, it is possible to distinguish between the front and back sides by comparing the peak signal intensities. However, if the gain that can be detected up to the limit sample is twice, each of the one-dimensional CCD cameras 41a, 41b Since the dynamic range is about 1 V, in the case of a normal defect on the back side 13, the peak signal intensity is saturated and there is no difference, making it difficult to distinguish between the front and back sides. However, on the other hand, the use of the number of defect detection pixels as the surface defect signal feature amount enables the determination of the front and back sides even when the peak signal intensity is saturated. In other words, the surface defect signal characteristic amount serving as the basis for the front / back determination is not limited to merely the peak signal intensity, but can be appropriately selected and adopted according to the purpose.

[0036]

[Table 2]

Further, the inspection apparatus of the second embodiment is used to measure a normal defect sample on the front side 12 of about 49 μm.
When the width defect was inspected at a conveyance speed of 2 m / min while maintaining the gain at 1 time, the results shown in the following Table 3 were obtained. That is, according to this result, if the detection signal becomes smaller, the difference in the number of surface defect detection pixels disappears, so for making a highly reliable front / back determination with a wider range of defect sizes, for example,
In the case of a small defect, it is desirable to use the peak signal intensity, and in the case of a large defect having a peak signal intensity of a certain level or more, it is desirable to combine at least two or more surface defect detection signal feature amounts such as using the number of surface defect detection pixels. .

[0038]

[Table 3]

The inspection apparatus according to the second embodiment has two one-dimensional CCs arranged on the front side and the back side, respectively.
By comparing the surface defect detection signal feature amount obtained by the D camera system to one another, it is also applicable to any test means for performing some judgment with respect to a surface defect, or a glass substrate or SiO ₂ in the liquid crystal art It is very useful for surface inspection of a substrate used for various display devices such as a plasma display or an arbitrary substrate with a film, including surface inspection of a glass substrate with a film such as ITO.

[0040]

As described above in detail in each embodiment, according to the present invention, the detection surfaces on the front and back sides of the inspection substrate conveyed by the conveyance mechanism are irradiated with linear band irradiation light. Each scattered light based on the defects on the front and back sides is captured by a one-dimensional CCD camera, converted into an electric signal, processed by the corresponding defect signal processor, and the characteristics of each defect detection signal by a microcomputer. Since the amounts are compared with each other, unlike the conventional method, the defect of the inspection substrate is not affected by the warpage of the substrate itself or the vertical vibration at the time of transport, and the defect of the inspection substrate is on the front side or the back side. This makes it possible to easily judge whether there is any defect or not with high reliability. As a result, it is possible to perform a defect inspection of the inspection base in accordance with mutually different inspection standards on the front side and the rear side. Excellent There is an advantage.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram schematically showing an outline of a surface defect inspection apparatus to which a first embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram schematically showing an outline of a surface defect inspection apparatus to which a second embodiment of the present invention is applied.

FIG. 3 is an explanatory view schematically showing an outline of a conventional light transmission type surface defect inspection apparatus.

FIG. 4 is an explanatory view schematically showing an outline of a conventional light reflection type surface defect inspection apparatus.

FIG. 5 is an explanatory view schematically showing an outline of a conventional scattered light detection type surface defect inspection apparatus.

[Explanation of symbols]

11 Glass substrate (inspection base) 11a SiO ₂ film or ITO on glass substrate surface
Film 12 Front side of glass substrate 13 Back side of glass substrate 14 Defects on front side 15 Defects on back side 21 Transport mechanism 22 Transport rollers of transport mechanism 31, 31a, 31b Light source 32, 32a, 32b Irradiation light 33, 33a , 33b Reflected light 34, 34a, 34b Scattered light 41, 41a, 41b One-dimensional CCD camera 42, 42a, 42b Defect signal processor 43 Microcomputer

Claims (5)

[Claims] In a state in which a surface of an inspection substrate having both front and back surfaces is irradiated with a linear band of irradiation light, scattered light generated by a surface defect of a surface to be irradiated is also primaryly reflected in addition to direct light or reflected light by the irradiation light. In an inspection method of detecting and detecting the presence or absence of a surface defect on the surface to be illuminated by a source CCD camera, the surface of the inspection substrate is illuminated with a linear band of illumination light on both the front and back surfaces. Scattered light generated by each surface defect of the surface to be illuminated
A D-camera is used to obtain the front and back surface defect detection signals, and the characteristic amount of the front side surface defect detection signal obtained by the front side one-dimensional CCD camera and the back side side defect detection signal obtained by the back side one-dimensional CCD camera. A method of inspecting a surface defect of an inspection substrate, comprising comparing a detected characteristic with a characteristic amount to determine whether the detected surface defect is a surface defect on the front side or a surface defect on the back side. 2. The method according to claim 1, wherein it is determined whether the surface defect is a front surface side defect or a rear surface side surface defect using at least two or more of the surface defect detection signal characteristic amounts. A method for inspecting a surface defect of an inspection substrate according to the above. 3. The method according to claim 1, wherein the inspection substrate is a light-transmitting inspection substrate. 4. In a state where a linear band-shaped irradiation light is irradiated on a surface of an inspection substrate having both front and back surfaces, scattered light generated by a surface defect of a surface to be irradiated other than a direct light or a reflected light by the irradiation light is primary. An inspection device for detecting and detecting the presence or absence of a surface defect on the surface to be irradiated by detecting and detecting light with an original CCD camera, comprising: transport means for continuously transporting the inspection substrate at a predetermined speed; Irradiation means for irradiating a linear band-shaped irradiation light from a light source at a predetermined incident angle to each specific position on both surfaces, and a defect caused by a surface defect of each irradiation surface other than direct light or reflected light by each irradiation light. Each one-dimensional C that captures scattered light and converts it into an electric signal
A CD camera; a respective defect signal processor for processing each of the surface defect detection signals detected by the respective one-dimensional CCD camera; and a respective surface for processing the respective signals processed by the respective defect signal processors. After obtaining the feature amount of the defect detection signal,
A surface defect of the inspection substrate, comprising: a microcomputer that compares the characteristic amount of the front side surface defect detection signal and the characteristic amount of the rear surface side defect detection signal to determine the front side and the rear side of the inspection substrate. Inspection equipment. 5. The inspection apparatus according to claim 4, wherein the inspection base is a light-transmitting inspection base.