JP2009047570A - Metal substrate surface inspection method and inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal substrate surface inspection method and its inspection device for simultaneously inspecting wiring patterns and plating, independently of very small fluctuations in the plating conditions. <P>SOLUTION: This metal substrate surface inspection method and its inspection device are equipped with a conveyance step for moving a substrate at a prescribed speed; an imaging step for photographing the surface of the substrate, in synchronization with the conveyance or at prescribed time intervals in a direction inclined by 0 to 10° from the direction of the normal to the substrate; a lighting step for thereto applying light as borrowed light within a wavelength band, maximizing the difference in the reflection intensity between a metal material of a non-plated part of the substrate and a plating material; a lighting semi-blocking step for selectively preventing a part of the light of a specific irradiation angle from an irradiation light from being irradiated thereto, the light of the specific irradiation angle differing slightly in the reflection intensity between the metal material of the non-plated part of the substrate and the plating material of a plated part; and an image processing step for extracting/automatically determining defective parts existing on the substrate surface, by using image data acquired in the imaging step. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a metal substrate surface inspection method and inspection apparatus, and more particularly to a lead frame wiring pattern and plating portion defect inspection method and inspection apparatus.

  An example of a substrate having a metal pattern in which the metal pattern is composed of a plated portion and a non-plated portion is a lead frame that is a base material of a semiconductor package. Hereinafter, this lead frame will be described as an example. In recent years, the packaging technology in the semiconductor technology field is becoming narrower with higher integration and higher functionality of semiconductor devices, and lead frames used in these packages are also becoming multi-pin and narrow pitch. Strict quality assurance is required.

  In addition, the lead frame manufacturing method includes a stamping method in which the metal thin plate-like base material is mechanically punched out using an ultra-precision mold, and etching is performed in which the metal is chemically corroded to form a pattern. There is a way.

  The inner lead of a general lead frame is designed to extend so as to spread radially with respect to the center of the die pad. In a semiconductor device using a lead frame, an IC chip is fixed to a die pad, and an electrode pad of the IC chip and a bonding portion at the tip of the inner lead are electrically connected by wire bonding or the like. As IC chips become more multifunctional, the number of electrode pads increases, and with the miniaturization of IC chips, the spacing between electrode pads is becoming narrower. Accordingly, the inner leads of the lead frame to be connected to the electrode pads are also multi-pinned, and the pitch between the inner leads and the inner lead width are various.

  When the pitch between the inner leads and the inner lead width are narrowed, the strength of the inner leads becomes weak, and the inner leads are deformed even by a slight external force. Therefore, in order to prevent contact between the inner leads and the suspension leads that support the die pad and the inner leads, electrical short circuit, deformation of the inner leads, etc., a lead frame with a protective tape applied to the inner leads and suspension lead portions Has been manufactured.

  In the lead frame manufacturing process, a predetermined shape is first formed by etching or stamping a metal thin plate-like substrate. Next, a metal plating such as silver is formed on the tip portion of the inner lead, a protective tape is applied to the inner lead portion, etc., and the tip of the inner lead portion is cut in some cases, and then a downset press is performed.

  FIG. 1 is a schematic plan view of a general lead frame. FIG. 1 schematically shows a case where the lead frame 1 is observed from the surface side. A lead frame 1 manufactured by an etching method or the like has a die pad 11, an inner lead 12, an outer lead 13, a dam bar 14, and a frame portion 15, and a portion where no wiring pattern is formed is called a space portion 19.

Thereafter, plating 16 for reducing the connection resistance between the semiconductor element and the bonding portion is applied to the inner lead 12. Next, in order to prevent contact between the inner leads and the suspension leads supporting the die pad and the inner leads, electrical short circuit, deformation of the inner leads, etc., a protective tape 17 is applied. As the protective tape 17, a polyimide tape is used in consideration of insulation and the like. Further, a step is formed on the suspension lead 18 by a downset press, and the inner lead tip is cut to remove conduction at the tip of the inner lead 12 in consideration of the loading of semiconductor elements on the die pad 11, and the lead frame is completed.

  The defect items in the final inspection of the lead frame manufactured by the above processes are diverse, such as pattern defects, lead deformation, protective tape defects, plating defects, downset press presence, etc., and product discrimination using automatic inspection machines. necessary.

  However, it is difficult to inspect all defects with a single inspection machine, and in particular, recently, the inspection requirements regarding tape and plating are further increased. The quality of the partial plating applied to the bonding part that is connected to the IC chip is particularly important. As a method for inspecting the plating state using image processing by imaging the plated part with a CCD camera or the like, for example, a patent Document 1 has been proposed.

  Although the technique described in Patent Document 1 can surely obtain the contrast difference between the non-plated portion and the plated portion on the surface of the metal pattern, strictly, the side taper portion of the wiring pattern having a three-dimensional shape is also included. An inspection method for judging whether the plating state including the quality is good or bad is desirable. Further, there has been a demand for an imaging and inspection method that can clearly separate the contrast between the metal surface and the plated portion and can simultaneously perform not only the plated portion but also the state of the metal surface.

  On the other hand, when the surface of the metal plate or the plated surface is observed microscopically, there are rolling flaws and irregularities due to the metal material manufacturing method, and minute brightness and darkness due to these irregularities occurs on the image, and depending on the threshold setting in image processing, overdetection It becomes an element, and stable automatic judgment is difficult.

  Therefore, means for imaging the surface of the substrate at an imaging angle of 0 ° to 10 °, illumination means in a wavelength region in which the difference in reflection intensity between the metal material of the non-plated portion and the plating material of the plated portion is maximized, and the solid angle A metal substrate surface inspection method and inspection apparatus using irradiation means for irradiating 2π indirect light have been proposed.

  This inspection method enables imaging of the plating state including the side taper portion of the wiring pattern having a three-dimensional shape, clearly separates the contrast between the metal surface and the plated portion, and also causes a rolling scratch caused by the metal material manufacturing method. It became possible to stabilize the over-detection element due to minute image contrast due to unevenness.

However, there has been a problem that the plated portion changes in surface condition and composition due to slight fluctuations in manufacturing conditions and the like, and inspection by contrast separation from the metal surface is not stabilized.
JP 2000-171402 A

  The present invention has been invented in view of the above-described problems, and provides an imaging method suitable for inspecting defects on the surface of a plated metal pattern with high accuracy regardless of slight variations in the manufacturing conditions of plating. In addition, an object of the present invention is to provide a wiring pattern and plating inspection apparatus capable of simultaneously inspecting a wiring pattern and plating in real time with high reliability.

The invention according to claim 1 of the present invention includes (1) a transporting stage for transporting a substrate having a metal pattern composed of a plated part plated on the surface and a non-plated part not plated at a predetermined speed; And (3) the imaging step of imaging the surface of the substrate from a direction inclined from 0 ° to 10 ° from the normal direction of the substrate in synchronization with the conveyance in the conveyance step or at predetermined time intervals; An illuminating step of irradiating light of a wavelength region in which the difference in reflection intensity between the metal material of the non-plated portion of the substrate and the plating material of the plated portion is maximum with indirect light by an illuminating means; (4) by the illuminating means A semi-illumination blocking step in which a difference in reflection intensity between the metal material of the non-plating portion of the substrate and the plating material of the plating portion is small, and a part of the light from a predetermined irradiation angle region is not irradiated. (5) obtained at the imaging stage An image processing / defect determination stage for determining defects present in the non-plated portion and the plated portion, using the image data of the surface of the substrate thus obtained. is there.

  This inspection method enables imaging of the plating state including the side taper part of the wiring pattern having a three-dimensional shape, clearly separates the contrast between the metal surface and the plating part, and also causes a rolling scratch caused by the metal material manufacturing method. The above-mentioned problem has been solved by maintaining the conventional effect of stabilizing the over-detection element due to light and dark minute images due to unevenness and unevenness, while further clarifying the contrast separation between the metal surface and the plated part by the semi-illumination prevention step It is.

  Next, the invention according to claim 2 of the present invention includes (1) a transport means for transporting a substrate having a metal pattern composed of a plated portion plated on the surface and a non-plated portion not plated at a predetermined speed. (2) Imaging means for imaging the surface of the substrate at a predetermined time interval in synchronization with conveyance by the conveyance means from a direction inclined by 0 ° to 10 ° from the normal direction of the substrate; 3) illuminating means for irradiating light with a wavelength in which the difference in reflection intensity between the metal material of the non-plated portion of the substrate and the plating material of the plated portion is maximized with indirect light; A semi-illumination preventing means for preventing a part of light from a predetermined irradiation angle region from being irradiated with a small difference in reflection intensity between the metal material of the non-plating portion of the substrate and the plating material of the plating portion of the irradiation light; (5) Before obtained by the imaging means An inspection apparatus for a metal substrate surface, comprising image processing / defect determination means for determining defects present in the non-plated portion and the plated portion using image data on the surface of the substrate.

  This inspection device enables imaging of the plating state including the side taper portion of the wiring pattern having a three-dimensional shape, clearly separates the contrast between the metal surface and the plating portion, and also causes a rolling scratch caused by the metal material manufacturing method. The above-mentioned problem has been solved by maintaining the conventional effect of stabilizing the over-detection element due to light and dark minute images due to unevenness and unevenness, while making the contrast separation between the metal surface and the plated part clearer by means of semi-illumination prevention means It is.

  As described above, according to the present invention, in the imaging of the wiring pattern on the surface of the metal substrate and the plating portion, image data having sufficient contrast is obtained and image processing is performed regardless of slight variations in the plating manufacturing conditions. Therefore, the wiring pattern defect and the plating appearance defect of the substrate having a metal pattern can be inspected with high accuracy and at the same time. In addition, it is possible to provide an inspection apparatus with excellent defect detection sensitivity.

  Embodiments of a metal substrate surface inspection method and a metal substrate surface inspection apparatus according to the present invention will be described below with reference to the drawings. FIG. 2 is a schematic configuration diagram showing an embodiment of the metal substrate surface inspection apparatus of the present invention.

The inspection apparatus for the surface of the metal substrate according to the present invention is to synchronize with the transport means 50 that moves the metal substrate 10 at a predetermined speed, and to synchronize with the transport means 50 and to reduce the influence of rolling scratches existing on the surface of the metal substrate 10. An imaging means 30 for imaging the surface of the metal substrate 10 with an imaging angle θ, and a metal material utilizing the wavelength range where the reflection intensity difference between the metal material of the metal substrate and the plating material is the largest with respect to the metal substrate 10 Using the image data obtained by photographing the surface of the metal substrate 10 with the illuminating means 20 including the dome illumination that irradiates indirect light and the optical material is separated from the plating material, the metal substrate 10 And a control / image processing means 40 for extracting and automatically determining a defective portion existing on the surface of the image.

  An inspection stage (not shown) on which the metal substrate 10 is placed and fixed is moved to the imaging area by the transport means 50 at a predetermined speed. At this time, the movement amount of the inspection stage attached to the transport means 50, that is, the movement amount of the metal substrate is increased. By obtaining a signal for each unit distance from a unit that measures accurately, and dividing and distributing the signal and sending this signal to the control / image processing means 40, scanning is performed so as not to be affected by the speed fluctuation of the inspection stage. Take an image. When the conveyance speed of the inspection stage can be regarded as constant within the resolution of the imaging means, a method of obtaining an image only by starting imaging with a trigger signal and imaging at a certain time interval can be considered, but as described above, always Imaging that is synchronized with the amount of movement of the inspection stage is more reliable.

  FIG. 3 is a schematic view showing an embodiment of the illumination means 20 of the present invention. As the illumination means 20, dome illumination that irradiates indirect light is used, and an imaging slit 21 is provided near the top of the hemispherical dome of the dome illumination, and the imaging means 30 images the substrate 10 through this slit. . The shape and size of the slit 21 are set in accordance with the shape and size of the field of view of the imaging means 30. That is, the slit 21 is preferably an elongated rectangular shape when the imaging means 30 is a line camera, and a rectangular shape close to a square when the imaging means 30 is an area camera. In either case, it is necessary that the size of the imaging means 30 is not obstructed. However, if the size is increased more than necessary, the balance of uniform irradiation from the dome illumination will be lost, so care must be taken. is there.

4A and 4B are schematic views showing an embodiment of the semi-illumination blocking means 22 according to the present invention. The illumination means 20 uses dome illumination that irradiates indirect light, and the semi-illumination prevention means 22 is disposed inside the dome illumination.
(A) is the perspective view which showed three-dimensionally the arrangement | positioning of a dome illumination and a semi-illumination prevention means.
(B) is a top view inside a dome illumination.

  The semi-illumination blocking means 22 is for intentionally changing the reflectivity in a part of the area from the solid angle 2π of the dome illumination that irradiates the indirect light that is the illumination means 20. It doesn't matter what method you use as long as it is variable. Specifically, the transmittance of the paint to be applied only in the region is changed, the paint is applied in a dot pattern only in the region, or a member capable of adjusting the transmittance such as an ND (Neutral Density) film is used. Thus, it is conceivable to change the reflectance of indirect light.

  The area of the semi-illumination blocking means 22 is an area parallel to the imaging area of the imaging means 30 and is arranged with reference to the imaging angle θ. Specifically, a range of 15 ° to 0 °, preferably a range of 5 ° to 0 ° is suitable. However, as long as the same effect can be expected, the space in the dome illumination may be used instead of being arranged in the region.

  In this embodiment, irradiation from the direction of the solid angle 2π of the dome illumination that irradiates the indirect light as the illumination means 20 is partially blocked. Since the uniform irradiation with the solid angle of 2π is not maintained, the accuracy of revealing the defect generated in the side taper portion is slightly deteriorated, or it comes from minute light and darkness due to rolling scratches and unevenness caused by the manufacturing method of the metal material. The effect of the conventional dome illumination is slightly weakened because the over-detecting element has some influence on the image.

However, since the difference in reflected light intensity between the metal surface of the non-plated portion and the plated portion is small, the coaxial direction irradiated light is blocked by the semi-illumination blocking means 22 to prevent the non-plated portion from being irradiated. Contrast separation between the metal surface and the plated portion can be made clearer, and a highly accurate and stable inspection can always be performed without depending on slight variations in the manufacturing conditions of plating.

  A wiring pattern formed by an etching method or the like has a cross-sectional shape close to a hexagon as the etching progresses from the surface on both sides toward the center in the thickness direction. The side taper portion is formed in a curve. When the illumination means is only coaxial incident light, the light is reflected on the surface of the wiring pattern, and the accuracy of revealing defects occurring between the wiring patterns and in the side taper portion is lowered.

  On the other hand, the dome illumination can irradiate many inspected components including the coaxial direction by irradiating the object to be inspected with a solid angle of 2π. . For dome lighting, a light exit is formed on the inner surface of the dome and light is irradiated directly from the direction of the solid angle 2π to the object to be inspected, and a light exit is formed on the inner surface of the dome and reflected on the inner surface of the dome. There is a type that irradiates the subject with indirect light, but either type may be used.

  Further, in order to reduce the influence of shading as much as possible, the dome inner diameter of the dome illumination is set to 2 W or more with respect to the width W of the substrate 10 having the metal pattern, and the entire surface of the substrate 10 having the metal pattern in one image pickup. It is preferable to be able to image. As the light source, a metal halide light source, a halogen light source, an LED light source, or the like is selected and used in consideration of the amount of light necessary for imaging.

  The imaging unit 30 repeatedly captures a predetermined area from a predetermined position on the substrate 10 having the metal pattern, and obtains image data of the entire surface of the substrate 10 having the metal pattern. The imaging angle θ of the imaging means 30 indicates the angle formed between the vertical direction of the substrate having the metal pattern and the optical axis, and the imaging angle θ is suitably about 3 to 10 °. The reason why the imaging angle θ is not 0 ° is to reduce the influence of fine irregularities such as rolling scratches on the surface of the metal pattern at the time of imaging to prevent erroneous detection and overdetection.

  Various types of cameras can be used as the image pickup means 30, but a line camera, an area camera, monochrome, color, or the like can be selected according to the application. In this embodiment, a monochrome line camera is used. Is shown.

  As a wavelength selection method, the irradiating means 20 illuminates with light having a wavelength of 400 nm or more and 600 nm or less, or an optical filter 35 that transmits a wavelength of 400 nm or more and 600 nm or less is attached to the imaging means 30. There are methods such as imaging only in the wavelength range.

  In this way, by selecting the wavelength of light used for imaging, the metal of the non-plated portion and the plated portion are optically separated, and a clear contrast for defect detection is obtained. Therefore, according to the metal and the plating material of the non-plated portion of the substrate 10 having the metal pattern to be imaged, the wavelength range in which the difference in reflection intensity is maximized is selected, and the metal material and the plating material of the non-plated portion are selected. As a result, the defect detection sensitivity is improved.

  The control / image processing means 40 controls the transport means 50 and performs processing for extracting a defective portion existing on the surface of the metal pattern using image data obtained by photographing the surface of the metal pattern.

FIG. 5 is a flowchart showing the overall operation of the image processing / defect determination means 40. The conveyance means 50 that moves the substrate 10 having the metal pattern at a predetermined speed, and the wavelength region where the difference in reflection intensity between the metal material of the non-plating portion and the plating material is the largest with respect to the metal pattern are utilized. The metallic material and the plating material are optically separated, and the illumination means 20 having the dome illumination for indirect light irradiation and the conveying means 50 are synchronized, and the surface of the metal pattern is photographed with an imaging angle θ. The metal pattern surface is sequentially imaged by the imaging means 30 (step S1).

  This image data is sent to the control / image processing means 40, and the metal surface of the non-plated part and each part information of the plated part are extracted from this image data (step S2). Further, defect detection / determination processing is executed using the extracted information (step S3). This defect detection / determination process is executed for all the wiring patterns and plating formed on the lead frame 40, and then the entire operation is completed (step S4, YES).

  6A schematically shows the inner lead 12, the plating part 16, and the space part 19, and FIG. 6B shows a profile on the line L1 in FIG. In this way, luminance information is separated in each of the inner lead 12, the plating 16, and the space portion 19. Therefore, in the defect detection / determination process (step S3), the obtained image is binarized and multi-valued to extract a defective part, or a reference image is held as master data in advance. It is possible to detect a defect by performing image processing such as pattern matching with the obtained image data and difference processing.

  In addition, with regard to the presence / absence of protective tape, displacement, and width abnormality, the standard protective tape edge information (coordinates) is obtained, and the abnormality can also be detected by performing measurement processing by calculating the number of pixels from this edge information. Can do. Further, in order to inspect whether the metal pattern is down-set press, a down-set press mark called a tool mark is generated on the suspension lead 18 as the down-set press is performed. The abnormality can be inspected by detecting the presence or absence by image processing.

  Hereinafter, specific examples of the present invention will be described in comparison with the results of comparative examples.

<Example 1>
In FIG. 7, a metal halide light source and dome illumination are used as the illumination unit 20, a film having a transmittance of 50% is disposed as the half illumination prevention unit 22 in an imaging angle range of 0 ° to 5 °, and the 8-bit 256 gradation is used as the imaging unit 30. This shows an inspection image near the inner lead plating of the lead frame when a monochrome line camera is used, the imaging angle θ is 5 °, and the optical filter 35 that transmits 400 nm to 600 nm is attached to the front surface of the imaging lens. .

<Comparative Example 1>
FIG. 8 shows the inner lead plating vicinity of the lead frame in the case of the first embodiment described above, in the case of the complete blocking that does not reflect the region instead of the semi-illumination blocking unit, and the case where the semi-illumination blocking unit is not arranged (FIG. 5 ( a) Profile on line L1). Here, the brightness level of the inner lead portion 12 is PL, the brightness level of the plating portion 16 is ML, and in the case of the first embodiment of the present invention where the half illumination blocking means 22 is provided, ML1 and the half illumination blocking means 22 are arranged. In the case of Comparative Example 1 that is not used, ML2 is used, and in the case of Comparative Example 2 that completely prevents reflection in the region, ML3 is used.

From the results shown in FIG. 8, it is possible to realize automatic extraction of the plating part and the metal pattern surface by having luminance information in each of the plating part 16, the inner lead part 12, and the space part 19 and setting appropriate threshold values. . However, since the luminance fluctuation near the luminance level PL on the surface of the metal pattern of the inner lead portion 12 is large, it can be seen that minute brightness and darkness due to rolling flaws and unevenness caused by the metal material manufacturing method are generated. This is because the presence of the semi-illumination blocking means 22 does not maintain the uniform irradiation of the solid angle 2π, and the effect of the conventional dome illumination is slightly weakened.

  However, comparing the brightness level ML1 when the semi-illumination blocking means 22 is present with the brightness level ML2 when the semi-illumination blocking means 22 is not present in the plated portion 16, contrast separation is better when the semi-illumination blocking means 22 is present. Can be confirmed more clearly. Therefore, a highly accurate and stable inspection can always be performed regardless of slight variations in the manufacturing conditions of plating. However, comparing the brightness level ML1 when the half illumination blocking means 22 is present and the brightness level ML3 when completely blocking, it can be confirmed that the contrast separation is clearer with complete blocking.

<Comparative example 2>
FIG. 9 shows the contrast difference between the luminance level ML of the plated portion 16 and the luminance level PL of the inner lead portion 12 when a film with various transmittances (%) is used as the semi-illumination blocking means 22, and at a certain same location. The relationship of the standard deviation of the inner lead part 12 is shown. When the transmittance of the film is 50% in Example 1, the transmittance of 0% is completely blocked, and the transmittance of 100% corresponds to the case where the semi-illumination blocking means 22 is not disposed.

  The standard deviation is adopted as an index indicating the luminance variation of the inner lead portion 12, and the larger the value, the larger the data variation. That is, when the standard deviation is large, an error between the luminance level PL of the inner lead portion 12 and the luminance of the inner lead portion 12 at each position increases. Since this variation is considered to be due to rolling scratches and unevenness caused by the metal material manufacturing method, the larger the standard deviation, the greater the influence of minute brightness and darkness due to rolling scratches and unevenness due to the metal material manufacturing method. Therefore, if the standard deviation is large, there is a high possibility of being an overdetection element depending on the threshold setting in the image processing, that is, it hinders the stabilization of the inspection.

  From FIG. 9, it can be confirmed that there is a correlation between the transmittance of the semi-illumination blocking means 22, the contrast difference between ML and PL, and the standard deviation of the inner lead portion 12. In order to obtain a larger contrast difference, a larger contrast difference can be obtained by lowering the transmittance of the semi-illumination blocking means 22, but the standard deviation of the inner lead portion 12 also increases in proportion thereto. That is, when the contrast difference between ML and PL is larger, the contrast separation becomes clearer, but in proportion to this, the standard of the inner lead portion 12 showing the influence of the minute flaws and darkness due to rolling scratches and unevenness caused by the metal material manufacturing method. The deviation will be high.

  As described above, by using the semi-illumination blocking means 22 of the embodiment of the present invention and changing the transmittance of the region, contrast separation between the metal surface and the plated portion, rolling scratches and unevenness due to the metal material manufacturing method are performed. It is possible to derive an optimum condition for stabilizing the overdetection element by the minute image brightness and darkness caused by. As a result, it is possible to solve the problem of instability of the inspection due to slight fluctuations in the manufacturing conditions of the plating part.

The top view which shows schematic shape of a lead frame. The schematic block diagram which shows the principal part structure of the inspection apparatus of the metal substrate surface which concerns on this invention. The schematic block diagram which shows the illumination means which concerns on one Embodiment of this invention. The schematic block diagram which shows the semi-illumination prevention means which concerns on one Embodiment of this invention. The flowchart which shows the whole schematic operation | movement of the inspection apparatus of the metal substrate surface of this invention. (A) The schematic plan view of inner lead plating vicinity of a lead frame. (B) Explanatory drawing which shows the line profile on the L1 line | wire in (a) in one Embodiment of this invention. The example of an image at the time of imaging by one Embodiment of this invention. The line profile on the L1 line in one embodiment of the present invention, and the line profile on the L1 line when the semi-illumination blocking means is not used and the reflection of the semi-illumination blocking area is completely blocked. Explanatory drawing showing the relationship between the transmittance of the semi-illumination blocking means, the contrast difference between ML and PL, and the standard deviation of the inner lead part

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lead frame 10 .... Substrate 11 with a metal pattern ... Die pad 12 ... Inner lead 13 ... Outer lead 14 ... Dam bar 15 ... Frame part 16 ... Plating 17 ... Protective tape 18 ... Hanging Lead 19 ··· Space portion 20 ··· Illuminating means 21 ··· Slit for imaging 22 ··· Semi-illumination blocking means 30 ··· Imaging means 35 ··· Optical filter 40 ··· Control · Image processing device 50 ··· Conveying means

Claims (2)

(1) A transport stage for transporting a substrate having a metal pattern composed of a plated part plated on the surface and a non-plated part not plated at a predetermined speed,
(2) An imaging step of imaging the surface of the substrate at a predetermined time interval in synchronization with the conveyance in the conveyance step from a direction inclined by 0 ° to 10 ° from the normal direction of the substrate;
(3) An illuminating step of irradiating light of a wavelength region in which the difference in reflection intensity between the metal material of the non-plated portion of the substrate and the plated material of the plated portion is maximized with indirect light by an illuminating unit;
(4) Of the light irradiated by the illumination means, a part of light from a predetermined irradiation angle region in which the difference in reflection intensity between the metal material of the non-plated portion of the substrate and the plating material of the plated portion is small is not irradiated. A semi-lighting adjustment stage,
(5) using image data of the surface of the substrate obtained in the imaging step, and an image processing / defect determination step for determining a defect present in the non-plated portion and the plated portion. A method for inspecting the surface of a metal substrate. (1) Conveying means for conveying a substrate having a metal pattern composed of a plated part plated on the surface and a non-plated part not plated at a predetermined speed;
(2) An imaging unit that images the surface of the substrate at a predetermined time interval in synchronization with conveyance by the conveyance unit from a direction inclined by 0 ° to 10 ° from the normal direction of the substrate;
(3) Illumination means for irradiating light of a wavelength region in which the difference in reflection intensity between the metal material of the non-plated portion of the substrate and the plating material of the plated portion is maximum with indirect light;
(4) Of the light irradiated by the illumination means, a part of light from a predetermined irradiation angle region in which the difference in reflection intensity between the metal material of the non-plated portion of the substrate and the plating material of the plated portion is small is not irradiated. Semi-lighting adjustment means to
(5) using image data of the surface of the substrate obtained by the imaging means, and image processing / defect determination means for determining defects present in the non-plated portion and the plated portion. An inspection device for the surface of a metal substrate.