Inspection system and inspection method

Abstract

To make a time that an inspection device can use for automatic inspection long.SOLUTION: A first inspection device 3 of an inspection system 1 includes a conveyance mechanism, a first stage, a first imaging unit and a first inspection part 301, and executes conveyance of an object onto the first stage by the conveyance mechanism, acquisition of a first picked-up image of the object on the first stage by the first imaging unit, and automatic inspection including defect inspection to the first picked-up image by the first inspection part. A second inspection device 4 includes a second stage, a second imaging unit and a second inspection part 401, and does not have a conveyance mechanism. The second imaging unit has the same configuration as the first imaging unit, and images the object mounted on the second stage to acquire a second picked-up image. The second inspection part shows position information of a plurality of inspection areas in the object, and also uses the second picked-up image to create data 51 for inspection showing an inspection threshold to each inspection area. The first inspection part can execute defect inspection using the data for inspection.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an inspection system and an inspection method. [Background technology]

[0002] Conventionally, inspection devices have been used that capture images of printed circuit boards on which patterns are formed, and then use the images to detect defects. A typical inspection device performs automatic inspections to automatically inspect a large number of printed circuit boards sequentially. For example, automatic inspections include transporting the printed circuit boards onto a stage using a transport mechanism, capturing images of the printed circuit boards on the stage using an imaging unit, and inspecting the captured images for defects using an inspection unit. Meanwhile, when inspecting a new type of printed circuit board in an inspection device, inspection data is created that indicates the position information of multiple inspection areas on the printed circuit board and the inspection thresholds for each inspection area. Then, the inspection data is used to automatically inspect multiple printed circuit boards of that type.

[0003] Regarding the creation of inspection data, Patent Document 1 discloses a visual inspection system equipped with a camera and an image processing device, in which a computer separate from the image processing device can perform a visual inspection similar to that performed by the image processing device. This allows the inspection performance of image processing software to be evaluated offline, making it easy to create image processing software suitable for visual inspection. Patent Document 2 discloses an inspection system in which a camera captures an image of a sample substrate and captures the sample image. The sample image is then captured offline, independent of the inspection line by the inspection system. By creating inspection data offline, the availability of the inspection system can be improved. Patent Document 3 discloses an inspection system in which, while the inspection system on the actual line is inspecting the object using preset inspection parameters, a virtual judgment is made on the quality of the object using an image of the inspected object, and new inspection parameters are created. Patent Document 4 discloses a recipe creation system for a critical dimension scanning electron microscope, in which a recipe for measuring the dimensions of a semiconductor element pattern with high precision is created offline using design data for the semiconductor element. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-43367 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-84388 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-151463 [Patent Document 4] Japanese Patent Application Laid-Open No. 2010-92951 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when creating inspection data offline, as with the inspection devices of Patent Documents 1 and 2, it is possible to ensure a certain amount of time available for the inspection device to use for automatic inspection, but it is not easy to extend this time further because the inspection device must take images of the printed circuit board and acquire the images used to create the inspection data.When creating inspection data using images of an object that has already been inspected, as with Patent Document 3, inspection data cannot be created if the design of the object has changed significantly, so it is necessary for an inspection device on the actual line to acquire the images used to create the inspection data, which places a limit on the time available for automatic inspection.

[0006] The present invention has been made in view of the above-mentioned problems, and has as its object to extend the time that an inspection device can be used for automatic inspection. [Means for solving the problem]

[0007] A first aspect of the present invention is an inspection system comprising: a first inspection device having a conveying mechanism, a first stage, a first imaging unit, and a first inspection unit, and performing an automatic inspection including conveying an object onto the first stage using the conveying mechanism, acquiring a first image of the object on the first stage using the first imaging unit, and inspecting the first image for defects using the first inspection unit; and a second inspection device having a second stage, a second imaging unit, and a second inspection unit, but no conveying mechanism for conveying the object onto the second stage, wherein the second imaging unit has a light source unit, optical system, and imaging unit of the same type as the light source unit, optical system, and imaging unit provided in the first imaging unit, and images the object placed on the second stage to acquire a second image, and the second inspection unit uses the second image to create inspection data indicating positional information of a plurality of inspection areas on the object and an inspection threshold for each inspection area, and the defect inspection can be performed in the first inspection unit using the inspection data.

[0008] Aspect 2 of the present invention is an inspection system of aspect 1, wherein the first inspection unit performs the defect inspection on the first captured image using correction data that corrects differences in shading of the captured image between the first imaging unit and the second imaging unit, or the second inspection unit creates the inspection data using the correction data.

[0009] Aspect 3 of the present invention is an inspection system of aspect 1 (which may be aspect 1 or 2), further comprising an imaging state monitoring unit that monitors the difference between the state of the first imaging unit and the state of the second imaging unit based on a first imaging image of an object acquired by the first imaging unit and a second imaging image of the same object acquired by the second imaging unit.

[0010] Aspect 4 of the present invention is an inspection system of aspect 1 (which may be any one of aspects 1 to 3), in which each of the first imaging unit and the second imaging unit acquires a visible light image of the object using visible light and an infrared light image of the object using infrared light, and each of the first inspection unit and the second inspection unit uses the visible light image and the infrared light image as the captured image.

[0011] A fifth aspect of the present invention is an inspection system according to any one of the first to fourth aspects, further comprising an inspection data storage unit that stores the inspection data, and the first inspection unit and the second inspection unit are capable of communicating with the inspection data storage unit.

[0012] A sixth aspect of the present invention is an inspection method in an inspection system, wherein the inspection system comprises a first inspection device having a conveying mechanism, a first stage, a first imaging unit, and a first inspection unit, and performing an automatic inspection including conveying an object onto the first stage by the conveying mechanism, acquiring a first image of the object on the first stage by the first imaging unit, and inspecting the first image for defects by the first inspection unit; and a second inspection device having a second stage, a second imaging unit, and a second inspection unit, and no conveying mechanism for conveying the object onto the second stage, wherein the second imaging unit has a light source unit, optical system, and imaging unit of the same type as the light source unit, optical system, and imaging unit provided in the first imaging unit, and the inspection method comprises the steps of: capturing an image of an object placed on the second stage by the second imaging unit to acquire a second image; creating inspection data by the second inspection unit using the second image, the inspection data indicating positional information of a plurality of inspection areas on the object and indicating an inspection threshold for each inspection area; and performing the defect inspection using the inspection data in the first inspection unit.

[0013] A seventh aspect of the present invention is an inspection method according to the sixth aspect, wherein when a part of the first imaging unit in the first inspection device is replaced with a replacement part, the replacement part is adjusted in the second imaging unit in the second inspection device, and then the part of the first imaging unit is replaced with the replacement part. [Effects of the Invention]

[0014] According to the present invention, the time that the first inspection device can be used for automatic inspection can be extended. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a block diagram showing a configuration of an inspection system. [Figure 2] FIG. 2 is a diagram showing the configuration of a first inspection device. [Figure 3] FIG. 2 is a diagram showing the configuration of a second inspection device. [Figure 4]FIG. 10 is a diagram showing the flow of inspection of a printed circuit board. [Figure 5] FIG. 10 is a diagram showing a master image of a target printed circuit board. [Figure 6] FIG. 10 is a diagram showing a high sensitivity region of the first SR part in the master image. [Figure 7] FIG. 10 is a diagram illustrating an example of an inspection threshold value for an inspection region. [Figure 8] FIG. 1 is a diagram showing a color chart. [Figure 9] 10 is a table showing the true color of each patch and the color of the second captured image. DETAILED DESCRIPTION OF THE INVENTION

[0016] FIG. 1 is a block diagram showing the configuration of an inspection system 1 according to one embodiment of the present invention. The inspection system 1 inspects printed circuit boards, and in one example, is used for final visual inspection of printed circuit boards. The inspection system 1 may also be used for inspections other than final visual inspection. The inspection system 1 includes a first inspection device 3, a second inspection device 4, and an inspection data storage unit 5. The first inspection device 3, the second inspection device 4, and the inspection data storage unit 5 are connected to each other so as to be able to communicate with each other via a network 8 such as a LAN or the Internet.

[0017] The first inspection device 3 comprises a first inspection main body 31, a first control unit 30, and an image processing circuit (image processing engine) 38. The first control unit 30 is responsible for overall control of the first inspection device 3. The first control unit 30 has a first inspection unit 301. The first inspection unit 301 performs processing related to defect inspection of the printed circuit board 9. The functions of the first control unit 30 are realized by a computer 39 (see FIG. 2) described below. The image processing circuit 38 performs predetermined image processing on the image of the inspection target. Details of the first inspection main body 31 will be described later.

[0018] The second inspection device 4 comprises a second inspection main body 41, a second control unit 40, and an image processing circuit 48. The second control unit 40 is responsible for overall control of the second inspection device 4. The second control unit 40 has a second inspection unit 401 and an image capture state monitoring unit 402. The second inspection unit 401 performs processing related to defect inspection of the printed circuit board 9. The image capture state monitoring unit 402 is used in a processing example described later. The function of the second control unit 40 is realized by a computer 49 (see FIG. 3) described later. The image processing circuit 48 performs predetermined image processing on an image of the inspection target. The image processing circuit 48 is an electric circuit of the same type (i.e., an electric circuit with the same design) as the image processing circuit 38 of the first inspection device 3. Details of the second inspection main body 41 will be described later.

[0019] The inspection data storage unit 5 is, for example, a NAS (Network Attached Storage), and is directly connected to the network 8. The inspection data storage unit 5 stores a plurality of inspection data 51. The inspection data 51 is used when inspecting the printed circuit board 9 for defects. The first and second correction data C1 and C2 in FIG. 1 are generated in a processing example described later. Depending on the design of the inspection system 1, the inspection data storage unit 5 may be realized by a storage device of another computer.

[0020] 2 is a diagram showing the configuration of the first inspection device 3. The first inspection device 3 includes a first inspection main body 31 and a computer 39. The computer 39 has a CPU, memory, etc., and executes a predetermined program to realize the functions of the first control unit 30 in FIG. 1. All or part of the functions of the first control unit 30 may be realized by a dedicated electric circuit. The image processing circuit 38 in FIG. 1 is, for example, built into the computer 39.

[0021] The first inspection body 31 includes a first stage 32, a first stage moving mechanism 33, a first imaging unit 34, and a transport mechanism 35. The first stage 32 holds the printed circuit board 9. Typically, the printed circuit board 9 is held on the first stage 32 in a horizontal position. The first stage moving mechanism 33 has a ball screw, a guide rail, a motor, etc., and moves the first stage 32 in a substantially horizontal direction along the main surface of the printed circuit board 9. In the example of FIG. 2, the first stage moving mechanism 33 can move the first stage 32 in two directions that are perpendicular to each other.

[0022] The first imaging unit 34 includes a light source 341, an optical system 342, and an imaging unit 343. The light source 341 emits light in a predetermined wavelength range. In this embodiment, the light source 341 emits white light that includes the entire wavelength range of visible light, but may emit light that includes other wavelength ranges. The imaging unit 343 has an imaging element such as a CCD sensor or a CMOS sensor. The optical system 342 includes a lens, a half mirror, and the like. The optical system 342 guides light from the light source 341 to the printed circuit board 9 on the first stage 32 and causes reflected light from the printed circuit board 9 to enter the imaging unit 343. As a result, the imaging unit 343 acquires an image (image data) of the printed circuit board 9. Hereinafter, the image of the printed circuit board 9 on the first stage 32 acquired by the first imaging unit 34 will be referred to as the "first captured image." The image acquired by the imaging unit 343 is a color image containing multiple color components (typically R (red), G (green), and B (blue)), but may also be a grayscale image depending on the design of the inspection system 1.

[0023] In one example of the first imaging unit 34, the imaging section 343 is a line sensor that simultaneously captures images of a linear region extending in one direction on the main surface of the printed circuit board 9. The first stage moving mechanism 33 continuously moves the first stage 32 in a direction approximately perpendicular to the linear region, thereby capturing a first captured image showing the entire printed circuit board 9. In the first inspection device 3, a plurality of first imaging units 34 may be arranged in the longitudinal direction of the linear region, and the entire printed circuit board 9 may be captured by the plurality of first imaging units 34. Alternatively, the first imaging units 34 may move relative to the printed circuit board 9 to capture a first captured image. The same applies to a second imaging unit 44 (see FIG. 3) described below.

[0024] The transport mechanism 35 includes a suction unit 351, a lifting unit 352, and a moving mechanism 353. The suction unit 351 holds the printed circuit board 9 by suction. The lifting unit 352 has, for example, an air cylinder or a motor, and moves the suction unit 351 in a substantially vertical direction. The moving mechanism 353 has, for example, a ball screw, a guide rail, a motor, and moves the suction unit 351 together with the lifting unit 352 in a substantially horizontal direction.

[0025] The first inspection device 3 performs an automatic inspection, sequentially inspecting a plurality of printed circuit boards 9 automatically. For example, a loading position P1 and an unloading position P2 are provided below the moving mechanism 353, and a plurality of printed circuit boards 9 before inspection are placed at the loading position P1. When the moving mechanism 353 positions the suction unit 351 above the loading position P1, the lifting unit 352 lowers the suction unit 351 to suck and hold the printed circuit board 9. After the suction unit 351 rises, the moving mechanism 353 moves the printed circuit board 9 together with the suction unit 351 and the lifting unit 352 above the first stage 32. Next, the lifting unit 352 lowers the suction unit 351, releasing the suction and holding of the printed circuit board 9, thereby placing the printed circuit board 9 on the first stage 32. In this manner, the transport mechanism 35 transports the printed circuit board 9 onto the first stage 32.

[0026] When the printed circuit board 9 is placed on the first stage 32, the first stage moving mechanism 33 moves the first stage 32 while the first imaging unit 34 captures an image of the printed circuit board 9 on the first stage 32. This results in a first captured image of the printed circuit board 9. The first captured image is input to the first inspection unit 301. The first inspection unit 301 uses the first captured image to inspect the printed circuit board 9 for defects. In the defect inspection, inspection data 51 is used. The inspection data 51 indicates position information (including size) of multiple inspection areas on the printed circuit board 9, and also indicates an inspection threshold for each inspection area. Details of the defect inspection and the inspection data 51 will be described later.

[0027] Meanwhile, in the transport mechanism 35, once the image of the printed circuit board 9 has been captured, the suction unit 351 sucks and holds the printed circuit board 9 on the first stage 32. After the suction unit 351 rises, the printed circuit board 9 moves above the carry-out position P2 together with the suction unit 351 and the lifting unit 352. Next, the suction unit 351 descends and releases the suction hold of the printed circuit board 9, thereby placing the printed circuit board 9 at the carry-out position P2. Thereafter, the next printed circuit board 9 from the carry-in position P1 is transported onto the first stage 32 in the same manner as the above operation.

[0028] As described above, in the first inspection apparatus 3, automatic inspection including the transportation of the printed circuit board 9 onto the first stage 32 by the transport mechanism 35, the acquisition of the first captured image of the printed circuit board 9 on the first stage 32 by the first imaging unit 34, and defect inspection of the first captured image by the first inspection unit 301 is sequentially performed on a plurality of printed circuit boards 9. Note that in the first inspection apparatus 3 of FIG. 2, the loading of the printed circuit board 9 from the loading position P1 onto the first stage 32 and the unloading of the printed circuit board 9 from the first stage 32 to the unloading position P2 are performed by a single mechanism, but the transport mechanism 35 may have separate loading mechanisms for loading the printed circuit board 9 and unloading mechanisms for unloading the printed circuit board 9. Furthermore, the loading position P1 and the unloading position P2 may be located away from each other.

[0029] FIG. 3 is a diagram showing the configuration of the second inspection device 4. The second inspection device 4 includes a second inspection main body 41 and a computer 49. In the example of FIG. 3, the main body of the computer 49 is housed inside a movable table 81, and the second inspection main body 41 is placed on the top plate of the movable table 81. The second inspection main body 41 is a tabletop type. The computer 49 has a CPU, memory, etc., and realizes the functions of the second control unit 40 in FIG. 1 by executing a predetermined program. All or part of the functions of the second control unit 40 may be realized by a dedicated electrical circuit. The image processing circuit 48 in FIG. 1 is, for example, built into the computer 49.

[0030] In this embodiment, the main configuration of the computer 49 is the same as that of the computer 39 of the first inspection apparatus 3. That is, the CPU, ROM, RAM, GPU, and motherboard of the computer 49 are of the same type as those of the CPU, ROM, RAM, GPU, and motherboard of the computer 39, respectively. The display unit (display), input unit, etc. may be different. In the example of FIG. 3, a touch panel 491 of the computer 49 is attached to a frame 411, which will be described later. Depending on the design of the inspection system 1, the main configuration of the computer 49 may differ from that of the computer 39.

[0031] The second inspection body 41 includes a second stage 42, a second stage moving mechanism 43, and a second imaging unit 44. The second stage 42 holds the printed circuit board 9. Typically, the printed circuit board 9 is held on the second stage 42 in a horizontal position. The second stage moving mechanism 43 has a ball screw, a guide rail, a motor, etc., and moves the second stage 42 in a substantially horizontal direction along the main surface of the printed circuit board 9. In the example of FIG. 3 , the second stage moving mechanism 43 can move the second stage 42 in one direction perpendicular to the plane of the paper. The second stage moving mechanism 43 may also be able to move the second stage 42 in multiple directions.

[0032] The second imaging unit 44 is attached to a gate-shaped frame 411 that straddles the second stage 42 and is disposed above the second stage 42. The second imaging unit 44 includes a light source 441, an optical system 442, and an imaging unit 443. The light source 441, the optical system 442, and the imaging unit 443 are of the same type as the light source 341, the optical system 342, and the imaging unit 343 provided in the first imaging unit 34, respectively. The light source 441 emits light in a predetermined wavelength range. The imaging unit 443 has an imaging element such as a CCD sensor or a CMOS sensor. The optical system 442 includes a lens, a half mirror, and the like. The optical system 442 guides light from the light source 441 to the printed circuit board 9 on the second stage 42 and causes reflected light from the printed circuit board 9 to enter the imaging unit 443. As a result, the imaging unit 443 acquires an image of the printed circuit board 9. Hereinafter, the image of the printed circuit board 9 on the second stage 42 acquired by the second imaging unit 44 will be referred to as the "second captured image." In one example of the second imaging unit 44, the imaging section 443 is a line sensor, and the second stage moving mechanism 43 continuously moves the second stage 42, thereby acquiring the second captured image showing the entire printed circuit board 9.

[0033] The second inspection device 4 does not have a transport mechanism for transporting the printed circuit board 9 onto the second stage 42. Therefore, when inspecting the printed circuit board 9 in the second inspection device 4, the operator places the printed circuit board 9 on the second stage 42. Next, the operator instructs the second control unit 40 to perform an imaging operation via the touch panel 491, whereby the second imaging unit 44 captures an image of the printed circuit board 9 on the second stage 42 and obtains a second captured image of the printed circuit board 9. The second inspection unit 401 performs defect inspection of the printed circuit board 9 using the second captured image. In the defect inspection, the inspection data 51 is used. After the imaging of the printed circuit board 9 is completed, the operator removes the printed circuit board 9 from the second stage 42. As described above, the second inspection device 4 can perform manual inspection, in which the printed circuit board 9 is manually transported onto the second stage 42. As described above, the second inspection device 4 can also perform defect inspection of the printed circuit board 9, but in the processing example described below, the second inspection device 4 is used to create the inspection data 51.

[0034] Next, the flow of inspection of a printed circuit board 9 in the inspection system 1 will be described with reference to Fig. 4. Here, a new type of printed circuit board 9 (hereinafter referred to as the "target printed circuit board 9") is inspected, so first, inspection data 51 to be used for defect inspection of the target printed circuit board 9 is created. Since the first inspection device 3 performs automatic inspection on a plurality of printed circuit boards 9 of other types, the inspection data 51 for the target printed circuit board 9 is created in the second inspection device 4.

[0035] In creating the inspection data 51, first, the CAM data (board design data) of the target printed circuit board 9 is input to the second inspection device 4 via the network 8 in FIG. 1, for example, and read (stored) in the second inspection section 401 (step S11). Next, images of a plurality of (e.g., 10 to 20) target printed circuit boards 9 are sequentially captured by the second imaging unit 44 (step S12). In the second inspection device 4, the operator places the target printed circuit boards 9 one by one on the second stage 42, and a plurality of second captured images showing the plurality of target printed circuit boards 9 are obtained.

[0036] The second inspection unit 401 generates a master image (reference image) of the second captured images by averaging the multiple second captured images. The value of each pixel in the master image is, for example, the average value of the values ​​of corresponding pixels in the multiple second captured images. Note that it is not always necessary to generate the master image from the multiple second captured images; for example, if the second captured image contains only a few defects, the second captured image may be used as the master image as is.

[0037] Next, the master image and the image represented by the CAM data are aligned (step S13). In this processing example, a plurality of marks are provided on the outer edge of the target printed circuit board 9, and one image is moved (moved in the pixel arrangement direction), rotated, and scaled relative to the other image so that the positions of the plurality of marks match in the master image and the image represented by the CAM data.

[0038] FIG. 5 is a diagram showing a portion of a master image of a target printed circuit board 9. In the printed circuit board 9, a wiring pattern made of a metal such as copper is formed on a resin base material. Furthermore, a solder resist (SR) layer is formed to cover most of the base material and the wiring pattern (for example, the area excluding a plated portion 95, which will be described later). Characters, symbols, etc. are printed on a portion of the solder resist layer using silk ink. In the master image of the target printed circuit board 9, the plated portion 95 (mainly consisting of pads, and therefore also referred to as a pad portion) which is the exposed portion of the wiring pattern, a first SR portion 96 which is the lower layer of the solder resist layer and is the portion of the wiring pattern, a second SR portion 97 which is the portion of the solder resist layer that directly contacts the base material, and a silk portion 98 which is the characters, symbols, etc. printed on the solder resist layer are set as individual inspection areas (step S14). The CAM data includes a layer showing the wiring pattern, a layer showing the solder resist layer, and a layer showing silk ink characters, symbols, etc., and the second inspection unit 401 can identify the plated portion 95, the first SR portion 96, the second SR portion 97, and the silk portion 98 using the CAM data.

[0039] In this processing example, high-sensitivity regions and low-sensitivity regions are further set in the inspection region. For example, as shown in FIG. 6, a portion of the first SR region 96 in the master image whose width is narrower than a predetermined value (the white region indicated by reference numeral 961 in FIG. 6) is set as the high-sensitivity region. The remaining portion of the first SR region 96 is set as the low-sensitivity region. High-sensitivity regions and low-sensitivity regions are set in the same manner for the second SR region 97. Furthermore, in the plating region 95, a portion whose area is smaller than a predetermined value is set as the high-sensitivity region, and the remaining portion of the plating region 95 is set as the low-sensitivity region. The high-sensitivity regions and low-sensitivity regions in each inspection region can also be identified using CAM data. Note that high-sensitivity regions and low-sensitivity regions may not be set for some inspection regions (e.g., the silk region 98, etc.).

[0040] Next, an inspection threshold is set for each inspection area. In this processing example, multiple types of inspections are performed on each inspection area, so an inspection threshold is set for each type of inspection. Here, multiple types of inspections will be described. The multiple types of inspections include, for example, comparison inspection, foreign body inspection, and unevenness inspection. In comparison inspection, the shape of the inspection area in the image to be inspected is compared with the shape of the inspection area in the master image. In one example, an image is obtained that shows the difference between the inspection area in a binary image obtained by binarizing the image to be inspected and the inspection area in a binary image obtained by binarizing the master image. Then, in the image, areas larger than the size threshold for comparison inspection are detected as defects.

[0041] In foreign substance inspection, the gradation value of each position in the inspection area in the image to be inspected is obtained for each color component. Of the set of positions (areas) where the gradation value is outside the range of the gradation thresholds (upper and lower limits) for foreign substance inspection, any area where the gradation value is larger than a size threshold is detected as a defect. In unevenness inspection, the color of each position in the inspection area in the image to be inspected is compared with the color of the corresponding position in the master image. Then, of the set of positions (areas) where the color difference is equal to or greater than the gradation threshold for unevenness inspection, any area where the color difference is larger than a size threshold is detected as a defect. Note that each of the comparison inspection, foreign substance inspection, and unevenness inspection may be performed using other known methods.

[0042] FIG. 7 is a diagram showing an example of inspection thresholds for inspection areas. The inspection thresholds for each inspection area are set for each low-sensitivity area and high-sensitivity area, and for each type of inspection. In the example of FIG. 7, defects in the mura inspection by the first SR unit 96 are classified into dark defects that are darker than the corresponding area in the master image and bright defects that are brighter than the corresponding area. Therefore, for each of the low-sensitivity area and the high-sensitivity area, the size threshold and gradation threshold for dark defects in the mura inspection (see the "Dark Defect Size" and "Dark Defect Sensitivity" columns in FIG. 7) are set as the inspection thresholds, and the size threshold and gradation threshold for bright defects in the mura inspection (see the "Bright Defect Size" and "Bright Defect Sensitivity" columns in FIG. 7) are set as the inspection thresholds. Inspection thresholds are set similarly for comparison inspection and foreign substance inspection. The inspection thresholds are set, for example, by an operator via an input unit of the computer 49. The second inspection unit 401 may perform defect inspection of the second captured image acquired in step S12 using the inspection thresholds set by the operator. If the defect inspection results in a large number of false reports (detection of false defects), the operator adjusts the current inspection threshold to an inspection threshold that can reduce the number of false reports.

[0043] Through the above processing, inspection data 51 indicating position information of multiple inspection areas on the target printed circuit board 9 and indicating the inspection threshold for each inspection area is created by the second inspection unit 401 using the second captured image (step S15). In this processing example, the inspection data 51 includes a master image. The inspection data 51 is input to and stored in the inspection data storage unit 5 via the network 8. The inspection system 1 may perform inspections other than comparison inspection, foreign matter inspection, and unevenness inspection, and may perform different inspections on multiple inspection areas. Furthermore, the inspection data 51 may include inspection parameters such as imaging conditions during inspection (such as the light intensity of the light source unit 441) and conditions for various image processing on the captured image. When creating the inspection data 51, the inspection parameters are also adjusted as necessary.

[0044] When automatic inspection is performed on a plurality (large number) of target printed circuit boards 9 in the first inspection device 3, the plurality of target printed circuit boards 9 are placed at the carry-in position P1. Furthermore, inspection data 51 for the target printed circuit boards 9 is input from the inspection data storage unit 5 to the first inspection unit 301. As described above, the configuration of the first imaging unit 34 is the same as that of the second imaging unit 44. Furthermore, the program portion related to defect inspection in the first inspection unit 301 is the same as that of the second inspection unit 401. Therefore, the inspection data 51 created by the second inspection unit 401 can be used directly in the first inspection unit 301.

[0045] Thereafter, the transport mechanism 35 transports the printed circuit board 9 onto the first stage 32, the first imaging unit 34 acquires a first captured image of the printed circuit board 9 on the first stage 32, and the first inspection unit 301 sequentially performs an automatic inspection on the plurality of target printed circuit boards 9, including a defect inspection of the first captured image. At this time, the defect inspection by the first inspection unit 301 is performed using the inspection data 51 for the target printed circuit board 9 created by the second inspection unit 401 (step S16). When the defect inspection has been performed on all of the target printed circuit boards 9 on the carry-in position P1, the inspection process of FIG. 4 is completed.

[0046] Here, consider an inspection system of the comparative example in which the second inspection device 4 is omitted. In the inspection system of the comparative example, the first inspection device 3 creates inspection data 51 for the target printed circuit board 9. Creating new inspection data 51 takes, for example, 20 to 30 minutes. During this time, the first inspection device 3 is occupied with creating the inspection data 51, and automatic inspection (mass production inspection) is stopped. As a result, the number of printed circuit boards 9 that are automatically inspected by the first inspection device 3 is reduced. In high-mix, low-volume production, for example, it may be necessary to create new inspection data 51 for 20 to 30 types of products per day. In this case, approximately half of the daily operating time of the first inspection device 3 is spent creating the inspection data 51. While it is possible to add a first inspection device 3 for creating the inspection data 51, the first inspection device 3 is expensive, which would significantly increase the cost of the inspection system.

[0047] In contrast, the inspection system 1 of FIG. 1 includes a first inspection device 3 having a conveying mechanism 35, a first stage 32, a first imaging unit 34, and a first inspection unit 301 and performing automatic inspection, and a second inspection device 4 having a second stage 42, a second imaging unit 44, and a second inspection unit 401 and no conveying mechanism for conveying a printed circuit board 9 onto the second stage 42. The second imaging unit 44 has a light source unit 441, an optical system 442, and an imaging unit 443 of the same type as the light source unit 341, the optical system 342, and the imaging unit 343 provided in the first imaging unit 34, and captures an image of the printed circuit board 9 placed on the second stage 42 to obtain a second captured image. The second inspection unit 401 uses the second captured image to create inspection data 51 that indicates position information of multiple inspection areas on the printed circuit board 9 and indicates inspection thresholds for each inspection area, and the first inspection unit 301 can perform defect inspection using the inspection data 51.

[0048] In the inspection system 1, the time required for creating the inspection data 51 in the first inspection device 3 can be omitted or shortened, thereby increasing the time that the first inspection device 3 can be used for automatic inspection. As a result, even in the case of high-mix low-volume production, the printed circuit boards 9 can be efficiently inspected. Furthermore, since the second inspection device 4 does not have a transport mechanism, the manufacturing cost of the inspection system 1 can be significantly reduced compared to when an additional first inspection device 3 is added (i.e., when multiple first inspection devices 3 are provided). The second inspection device 4 can also be used as an independent inspection device. By using the second inspection device 4 as a manual inspection device during periods when the inspection data 51 is not being created, it is possible to improve the throughput of mass production inspection. The inspection data 51 may be created by the first inspection unit 301 during periods when the operation rate of the first inspection device 3 is low.

[0049] Preferably, the inspection system 1 further includes an inspection data storage unit 5 that stores the inspection data 51, and the first inspection unit 301 and the second inspection unit 401 are capable of communicating with the inspection data storage unit 5. In other words, the first inspection unit 301 and the second inspection unit 401 share the inspection data 51 via the inspection data storage unit 5. If the inspection data 51 were stored in the first inspection unit 301 or the second inspection unit 401, reading the inspection data 51 from outside could impose a load on the inspection units 301 and 401, which could interfere with the inspection of the printed circuit board 9. In contrast, by providing a dedicated storage unit (inspection data storage unit 5) as described above, the inspection data 51 can be easily handled without placing an excessive load on the inspection units 301 and 401. Depending on the design of the inspection system 1, the inspection data 51 may be stored in the first inspection section 301 and / or the second inspection section 401, and the inspection data storage section 5 may be omitted.

[0050] 4 includes a step of capturing an image of the printed circuit board 9 placed on the second stage 42 by the second imaging unit 44 to obtain a second captured image, a step of creating inspection data 51 for the printed circuit board 9 by the second inspection section 401 using the second captured image, and a step of performing a defect inspection in the first inspection section 301 using the inspection data 51. This makes it possible to omit or shorten the time required to create the inspection data 51 in the first inspection device 3, thereby increasing the time available for the first inspection device 3 to perform automatic inspection.

[0051] The first imaging unit 34 and the second imaging unit 44 use light source units 341, 441 that emit visible light, but for example, a light source unit that emits infrared light may be provided in addition to the light source units 341, 441. In this case, each of the first imaging unit 34 and the second imaging unit 44 acquires a visible light image of the printed circuit board 9 using visible light and an infrared light image of the printed circuit board 9 using infrared light.

[0052] When creating the inspection data 51, the second inspection device 4 acquires visible light images while the second stage 42 moves continuously in one direction, and acquires infrared light images while the second stage 42 moves continuously in the direction opposite to the one direction. The second inspection unit 401 generates master images for each of the visible light images and the infrared light images, and sets an inspection threshold for each inspection area. In other words, the inspection data 51 is created using the visible light images and the infrared light images as second captured images. In the automatic inspection by the first inspection device 3, similar to the second inspection device 4, visible light images are acquired while the first stage 32 moves continuously in one direction, and infrared light images are acquired while the first stage 32 moves continuously in the direction opposite to the one direction. The first inspection unit 301 performs defect inspection for each of the visible light images and the infrared light images. In other words, defect inspection is performed using the visible light images and the infrared light images as first captured images.

[0053] As described above, when capturing visible light images and infrared light images, the time required to capture the captured images and create the inspection data 51 is long. Even in this case, in the inspection system 1 in which the second inspection device 4 captures images of the printed circuit board 9 and creates the inspection data 51, the time required to create the inspection data 51 in the first inspection device 3 can be eliminated or shortened, thereby extending the time available for the first inspection device 3 to perform automatic inspection. Furthermore, by using infrared light, an image in which the solder resist layer is made nearly transparent can be obtained, making it possible to detect defects in the layer below the solder resist layer. As a result, high-precision inspection can be performed using visible light images and infrared light images. The first imaging unit 34 and the second imaging unit 44 may be provided with separate imaging units for visible light images and infrared light images. In this case, the first imaging unit 34 and the second imaging unit 44 use the same type of imaging unit for visible light images and the same type of imaging unit for infrared light images.

[0054] Next, a process for correcting differences in shading that may occur between the first and second captured images due to individual differences in the components when the same printed circuit board 9 is captured by the first and second imaging units 34 and 44 will be described. Examples of such differences include differences in dynamic range and gamma curve. Here, since the first and second captured images are color images, differences in shading for each of R, G, and B are corrected. As previously mentioned, the first and second captured images may be grayscale images, and in this case, the differences in shading are corrected using the same process as described below.

[0055] Fig. 8 is a diagram showing a color chart 71. In the color chart 71, different colors are assigned to a plurality of patches 711 (24 in Fig. 8), and R, G, and B gradation values ​​are defined for each patch 711. In the following explanation, the colors that follow the changes in the R, G, and B gradation values ​​defined in the color chart 71 are referred to as "true colors."

[0056] First, in the second inspection device 4, the second imaging unit 44 captures an image of the color chart 71. This captures a second captured image showing the color chart 71, and R, G, and B gradation values ​​are identified for each of the multiple patches 711. As a result, as shown in FIG. 9, a table is obtained in which the R, G, and B gradation values ​​indicating the true color of each patch 711 correspond to the R, G, and B gradation values ​​indicated in the second captured image. The second inspection unit 401, for example, obtains second correction data indicating the correspondence between the gradation values ​​of the second captured image and the true color gradation values ​​by calculating, for each color component, the difference between the true color gradation value of the patch 711 and the gradation value of the second captured image (i.e., capable of converting the gradation values ​​of the second captured image to the true color gradation values). The second correction data may be acquired using various known methods and may be a table, a function, or the like (the same applies to the first correction data described below).

[0057] Similarly, in the first inspection device 3, the color chart 71 is imaged by the first imaging unit 34, and a first captured image showing the color chart 71 is acquired. In the first inspection section 301, for example, for each color component, first correction data indicating the correspondence between the gradation values ​​of the first captured image and the gradation values ​​of the true color is acquired by calculating the difference between the gradation values ​​of the true color of the patch 711 and the gradation values ​​of the first captured image. In this processing example, as shown in FIG. 1, the first correction data C1 and the second correction data C2 are stored in the inspection data storage section 5.

[0058] In the inspection process of FIG. 4 for the target printed circuit board 9, the second inspection device 4 creates inspection data 51 without using the second correction data C2 (steps S11 to S15). When the first inspection device 3 performs automatic inspection of multiple target printed circuit boards 9 (step S16), the inspection data 51, the first correction data C1, and the second correction data C2 for the target printed circuit board 9 are input from the inspection data storage unit 5 to the first inspection unit 301. In the first inspection unit 301, the master image included in the inspection data 51 is converted using the second correction data C2. As a result, when assuming the printed circuit board 9 from which the master image is acquired by the second imaging unit 44, an image is obtained that approximately represents the R, G, and B gradation values ​​of the true colors of the printed circuit board 9. Next, the image is converted using the first correction data C1. As a result, assuming that the printed circuit board 9 is a circuit board 9 whose master image is acquired by the second imaging unit 44, an image similar to an image obtained by imaging the printed circuit board 9 by the first imaging unit 34 (i.e., an image conforming to the gradation characteristics of the first imaging unit 34) is obtained as the converted master image. Furthermore, the gradation threshold values ​​included in the inspection data 51 are also converted using the second correction data C2 and the first correction data C1, similar to the master image.

[0059] In the automatic inspection by the first inspection device 3, the automatic inspection including the conveyance of the printed circuit board 9 onto the first stage 32 by the conveyance mechanism 35, the acquisition of a first captured image of the printed circuit board 9 on the first stage 32 by the first imaging unit 34, and a defect inspection of the first captured image by the first inspection unit 301 is sequentially performed on a plurality of target printed circuit boards 9. At this time, the first inspection unit 301 performs a defect inspection of the plurality (numerous) of first captured images using the converted master image and the converted gradation threshold value. As a result, even if there is a difference in shading between the first captured image acquired by the first imaging unit 34 and the second captured image acquired by the second imaging unit 44, the defect inspection of the first captured image is appropriately performed using the inspection data 51 created based on the second captured image.

[0060] As described above, in the preferred inspection system 1, the first inspection unit 301 performs defect inspection on the first captured image using correction data (first correction data C1 and second correction data C2 in the above) that corrects differences in shading between the captured images of the first imaging unit 34 and the second imaging unit 44. This allows the first inspection unit 301 to accurately perform defect inspection using the inspection data 51 created in the second inspection device 4. Note that correction data indicating the correspondence between the gradation values ​​of the first captured image and the gradation values ​​of the second captured image may be generated, and a converted master image in accordance with the gradation characteristics of the first imaging unit 34 may be obtained by performing a single conversion on the master image.

[0061] In the inspection system 1, when creating the inspection data 51, the second inspection unit 401 may convert the second captured image using the second correction data C2 and the first correction data C1 to acquire an image in accordance with the gradation characteristics of the first imaging unit 34. In this case, a master image is generated based on the second captured image, and a gradation threshold (and a size threshold) is set, and the inspection data 51 is created. The first inspection unit 301 uses the inspection data 51 as is. In this way, even when the second inspection unit 401 creates the inspection data 51 using the correction data (the first correction data C1 and the second correction data C2), the first inspection unit 301 can accurately perform defect inspection using the inspection data 51. Depending on the design of the inspection system 1, defect inspection may be performed by the second inspection unit 401 using the second correction data C2 to create inspection data 51 that conforms to the true color gradation characteristics, and the first inspection unit 301 using the first correction data C1 to generate a first captured image that conforms to the true color gradation characteristics.

[0062] Next, a process for monitoring the state of the first imaging unit 34 while continuing automatic inspection in the first inspection device 3 will be described. In this process example, the imaging state monitoring unit 402 in Fig. 1 is used. Also, it is assumed that when the first imaging unit 34 and the second imaging unit 44 are in a normal state, there is almost no difference in shading between the first and second captured images.

[0063] In the second inspection device 4, for example, the state of the second imaging unit 44 is periodically checked. In one example of checking the state of the second imaging unit 44, the color chart 71 in FIG. 8 is captured by the second imaging unit 44. Then, it is checked whether the gradation values ​​of each color component of the second captured image, which is the output of the second imaging unit 44, approximately match the gradation values ​​of the second captured image obtained by previously capturing the color chart 71 (the output of the second imaging unit 44 in a normal state), i.e., whether the state of the second imaging unit 44 is maintained normally. If the state of the second imaging unit 44 is abnormal, predetermined maintenance work is performed. This keeps the state of the second imaging unit 44 normal.

[0064] In the first inspection device 3, automatic inspection continues, and the operator removes the printed circuit board 9 whose image has been captured by the first imaging unit 34 and places it on the second stage 42 of the second inspection device 4. Thereafter, the printed circuit board 9 is imaged by the second imaging unit 44, and a second captured image is obtained. In addition, the first captured image of the printed circuit board 9 is input to the imaging status monitoring unit 402 of the second inspection device 4 via the network 8. The imaging status monitoring unit 402 compares the first and second captured images of the printed circuit board 9, and calculates a value indicating the difference between them.

[0065] In calculating the value indicating the difference, for example, the sum of squares of the differences in gradation values ​​of all pixels for each color component between the first captured image and the second captured image is calculated. If the sum of squares is greater than a predetermined value, it is determined that there is a difference (large difference) between the state of the first imaging unit 34 and the state of the second imaging unit 44, and a notification is issued to the operator urging them to perform maintenance on the first imaging unit 34. The notification to the operator is issued by a well-known method, such as displaying on the touch panel 491 of the second inspection device 4. If the sum of squares is equal to or less than a predetermined value, it is determined that there is no difference (small difference) between the state of the first imaging unit 34 and the state of the second imaging unit 44, and no notification is issued to the operator. The value indicating the difference may be something other than the sum of squares of the differences in gradation values. In addition, the imaging state monitoring unit 402 may determine whether there is a difference between the state of the first imaging unit 34 and the state of the second imaging unit 44 by comparing values ​​(comparison values) indicating the state of the first captured image, such as the average gradation value or contrast value of the first captured image, with values ​​indicating the state of the second captured image.

[0066] As described above, the imaging state monitoring unit 402 monitors the difference between the state of the first imaging unit 34 and the state of the second imaging unit 44 based on the first captured image of one printed circuit board 9 captured by the first imaging unit 34 and the second captured image of the same printed circuit board 9 captured by the second imaging unit 44. This makes it possible to easily detect a change in the state of the first imaging unit 34 (the occurrence of an abnormality) while continuing the automatic inspection in the first inspection device 3, assuming that the state of the second imaging unit 44 is maintained normal. Note that, in the first imaging unit 34 and the second imaging unit 44 in the normal state, a difference in shading may occur between the first captured image and the second captured image. In this case, for example, the first captured image and / or the second captured image is corrected using correction data (first correction data C1 and second correction data C2), and the difference between the state of the first imaging unit 34 and the state of the second imaging unit 44 is monitored based on the corrected captured image.

[0067] Next, a preferred process for replacing a part of the first imaging unit 34 in the first inspection device 3 in the inspection system 1 will be described. In the following description, a part that is installed in place of the part in question in the first imaging unit 34 will be referred to as a "replacement part." The replacement part may be a new part or a reused part.

[0068] When replacing a part of the first imaging unit 34, the replacement part is first replaced with a corresponding part of the second imaging unit 44 in the second inspection device 4. Then, a predetermined adjustment of the replacement part is performed in the second imaging unit 44. For example, if the replacement part is a light source unit and adjustment of the intensity of emitted light or the like is required, the intensity of the emitted light (e.g., adjustment of the input current value) is performed with the replacement part attached to the second imaging unit 44. After the adjustment of the replacement part is completed, the replacement part is removed from the second imaging unit 44 and replaced with a part of the first imaging unit 34. The replacement part may be the entire light source unit or only a part of the light source unit. The replacement part may also be all or a part of the optical system or the imaging unit. For example, if the replacement part is a focus mechanism, which is part of the optical system, a mechanical adjustment of the focus mechanism is performed in the second imaging unit 44, and then the focus mechanism is replaced with a corresponding part of the first imaging unit 34.

[0069] As described above, in a preferred inspection system 1, when a part of the first imaging unit 34 in the first inspection apparatus 3 is replaced with a replacement part, the replacement part is adjusted in the second imaging unit 44 in the second inspection apparatus 4, and then the part in the first imaging unit 34 is replaced with the replacement part. Since the adjustment of the replacement part is already completed in the second imaging unit 44, which has the same configuration as the first imaging unit 34, it is possible to shorten or eliminate the time required to adjust the replacement part in the first imaging unit 34. As a result, the first inspection apparatus 3 can be restored in a short time, and the time that the first inspection apparatus 3 is available for automatic inspection can be extended.

[0070] The inspection system 1 and the inspection method described above can be modified in various ways.

[0071] In the above-mentioned inspection system 1, when correction data (in the above, the first correction data C1 and the second correction data C2) is used to correct the difference in shading of the captured images between the first imaging unit 34 and the second imaging unit 44, the types of all or part of the light source section 441, optical system 442 and imaging section 443 provided in the second imaging unit 44 may be different from those of the first imaging unit 34.

[0072] As described above, the first stage 32 in the first inspection device 3 may move relative to the first imaging unit 34. Depending on the size of the printed circuit board 9 to be imaged, the first image of the printed circuit board 9 may be acquired without moving the first stage 32. In this case, the first stage moving mechanism 33 may be omitted. The same applies to the second inspection device 4.

[0073] In the above embodiment, the printed circuit board 9 is the object to be inspected in the inspection system 1, but the object to be inspected may be a glass substrate, a semiconductor substrate, etc. other than the printed circuit board 9, or may be something other than a substrate, such as a mechanical part.

[0074] The configurations in the above-described embodiment and each modification may be combined as appropriate as long as they are not mutually contradictory. [Explanation of symbols]

[0075] 1. Inspection system 3. First Inspection Device 4. Second Inspection Equipment 5. Inspection data storage unit 9 Printed Circuit Board 32 Stage 1 34 First imaging unit 35 Transport mechanism 42 Stage 2 44 Second imaging unit 51 Test Data 301 First Inspection Department 341,441 Light source section 342,442 Optical system 343,443 Imaging unit 401 Second Inspection Department 402 Imaging status monitoring unit C1, C2 correction data Steps S11 to S16

Claims

1. 1. An inspection system comprising: a first inspection device having a transport mechanism, a first stage, a first imaging unit, and a first inspection section, and performing an automatic inspection including transporting an object onto the first stage by the transport mechanism, acquiring a first image of the object on the first stage by the first imaging unit, and inspecting the first image for defects by the first inspection section; a second inspection device having a second stage, a second imaging unit, and a second inspection section, but not having a transport mechanism for transporting an object onto the second stage; Equipped with the second imaging unit has a light source unit, an optical system, and an imaging unit of the same type as the light source unit, the optical system, and the imaging unit provided in the first imaging unit, and images an object placed on the second stage to obtain a second captured image; the second inspection unit creates inspection data indicating position information of a plurality of inspection areas in the object and an inspection threshold for each inspection area using the second captured image; an inspection system in which the first inspection unit is capable of performing the defect inspection using the inspection data;

2. 10. The inspection system of claim 1, An inspection system in which the first inspection unit performs the defect inspection on the first captured image using correction data that corrects differences in shading of the captured image between the first imaging unit and the second imaging unit, or the second inspection unit creates the inspection data using the correction data.

3. 10. The inspection system of claim 1, An inspection system further comprising an imaging state monitoring unit that monitors the difference between the state of the first imaging unit and the state of the second imaging unit based on a first image of an object acquired by the first imaging unit and a second image of the same object acquired by the second imaging unit.

4. 10. The inspection system of claim 1, each of the first imaging unit and the second imaging unit captures a visible light image of an object using visible light and an infrared light image of the object using infrared light; An inspection system in which the first inspection unit and the second inspection unit use the visible light image and the infrared light image as captured images, respectively.

5. 5. The inspection system according to claim 1, further comprising a test data storage unit that stores the test data; An inspection system in which the first inspection unit and the second inspection unit are capable of communicating with the inspection data storage unit.

6. An inspection method in an inspection system, comprising: the inspection system, a first inspection device having a transport mechanism, a first stage, a first imaging unit, and a first inspection section, and performing an automatic inspection including transporting an object onto the first stage by the transport mechanism, acquiring a first image of the object on the first stage by the first imaging unit, and inspecting the first image for defects by the first inspection section; a second inspection device having a second stage, a second imaging unit, and a second inspection section, but not having a transport mechanism for transporting an object onto the second stage; Equipped with the second imaging unit has a light source unit, an optical system, and an imaging unit of the same type as those of the light source unit, the optical system, and the imaging unit provided in the first imaging unit, The inspection method comprises: capturing an image of the object placed on the second stage with the second imaging unit to obtain a second captured image; creating inspection data indicating position information of a plurality of inspection areas in the object and indicating an inspection threshold value for each inspection area by the second inspection unit using the second captured image; performing the defect inspection using the inspection data in the first inspection unit; An inspection method comprising:

7. The inspection method according to claim 6, An inspection method in which, when replacing a part of the first imaging unit with a replacement part in the first inspection device, the replacement part is adjusted in the second imaging unit in the second inspection device, and then the part of the first imaging unit is replaced with the replacement part.

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