Flux coating state inspection device and flux coating state inspection method

Abstract

To provide a flux coating state inspection device or the like, capable of obtaining a good inspection accuracy while enabling the inspection region setting with relatively simple processing.SOLUTION: A flux coating state inspection device 12 comprises: an illuminating device 321 that illuminates an ultraviolet light to a substrate; a camera 322 that images the ultraviolet light irradiated to the substrate; an inspection region setting part 335 that corresponds to a component scheduled to be mounted by using a reference part provided to the substrate as a reference, and sets an inspection region in a substrate 1 that concludes a plurality of electrodes to which the component is mounted is to each component; and a determination part 336 that performs a quality determination in accordance with a coating state of a flux on the basis of a luminance image obtained by imaging the ultraviolet light irradiated to the inspection region by the camera 322. The determination part 336 calculates an area of a part having a luminance of which a threshold value of a predetermined luminance or larger in an inspection region in each inspection region, and determines a coating state of a flux on the basis of the area to be calculated.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to an inspection device and an inspection method for inspecting the state of flux applied to a board. [Background technology]

[0002] Generally, when mounting electronic components on a printed circuit board, cream solder is first printed on the electrodes arranged on the printed circuit board. Next, the electronic components are temporarily attached to the printed circuit board on which the cream solder is printed, based on the viscosity of the cream solder. After the electronic components are temporarily attached, the printed circuit board is introduced into a reflow furnace, and soldering is performed by going through a predetermined reflow process.

[0003] Furthermore, in order to achieve miniaturization and suppression of mounting defects, a semiconductor package with a plurality of spherical bumps (solder balls) regularly arranged on the bottom surface, such as a ball grid array (BGA), has been proposed as an electronic component. When mounting such a semiconductor package as an electronic component on a printed circuit board, it is sufficient to place the bumps on the electrodes, and there is no need to print cream solder. However, when mounting such a semiconductor package on a printed circuit board, it is preferable to apply flux to the electrodes in order to increase the wettability of the solder before placing the bumps on the electrodes.

[0004] Here, if the flux is applied to the electrodes in an inappropriate state, there is a risk of problems such as insufficient bonding strength of the electronic component to the printed circuit board. Therefore, it is preferable to inspect the flux application state before placing the electronic component on the printed circuit board. As an inspection device for inspecting the flux application state, there is known one that inspects the flux application state by comparing the flux photographed by an imaging device with the pattern-recognized electrodes (circuit pattern) (see, for example, Patent Document 1, etc.).

[0005] Incidentally, in the inspection device described in the above Patent Document 1, the area of ​​the applied flux is set to be larger than the entire area of ​​the electrode (printed circuit), and the flux is opaque. Therefore, although it is possible to photograph the flux with a camera, it is not possible to photograph the electrode (printed circuit) to which the flux is applied. Therefore, in the inspection, the applied state of the flux is inspected by using, as the inspection area, not the actual electrode but only the pattern-recognized electrode, that is, by using the virtually estimated area of ​​the electrode. Therefore, in order to ensure sufficient inspection accuracy, it is necessary to set an appropriate inspection area to match the position of the actual electrode.

[0006] Here, as a method for setting an appropriate inspection area that matches the actual position of the electrodes, for example, a method using marks provided on a printed circuit board as a reference can be considered (for example, see Patent Document 2, etc.). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2010-271165 A [Patent Document 2] JP 2005-286309 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, when using marks as references, when inspecting a printed circuit board on which a plurality of electrodes are provided at an extremely small pitch (for example, a printed circuit board on which a semiconductor package such as a BGA is mounted), extremely high-precision processing may be required to set an appropriate inspection area. Such high-precision processing increases the processing load and ultimately reduces the inspection efficiency.

[0009] On the other hand, if the processing is simplified to reduce the processing burden, a "deviation" is more likely to occur between the test area and the actual electrode position, and as a result, there is a risk that sufficient test accuracy cannot be ensured.

[0010] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a flux application state inspection device and the like that can obtain good inspection accuracy while enabling the inspection area to be set through relatively simple processing. [Means for solving the problem]

[0011] The following describes each of the means suitable for achieving the above object. Note that, as necessary, the specific effects of the corresponding means will be added.

[0012] Means 1. A flux application state inspection device for inspecting flux that is applied to an electrode of a substrate and is capable of absorbing ultraviolet light, comprising: An irradiation means capable of irradiating the substrate with ultraviolet light; an imaging means capable of imaging the ultraviolet light irradiated onto the substrate; an inspection area setting means for setting, for each component, an inspection area on the board that corresponds to a component to be mounted and includes a plurality of electrodes on which the component is to be mounted, using a reference portion provided on the board as a reference; a determination unit that performs a quality determination on a state of application of the flux based on an image obtained by imaging the ultraviolet light irradiated onto the inspection area by the imaging unit while irradiating the ultraviolet light onto the inspection area by the irradiation unit, the determining means is configured to calculate an area of ​​a portion in each of the inspection regions having a luminance equal to or greater than a predetermined luminance threshold, and to determine the state of flux application based on the calculated area.

[0013] According to the above-mentioned means 1, the inspection area setting means sets an inspection area that corresponds to the component to be mounted and includes a plurality of electrodes on which the component is to be mounted. For example, when the component to be mounted is a BGA and the component is to be mounted on a plurality of electrodes, an area including these electrodes is set as the inspection area. In other words, instead of setting each individual electrode as an inspection area, one inspection area is set corresponding to a plurality of electrodes on which one component is to be mounted. Therefore, since it is sufficient to set the inspection area relatively roughly, the inspection area can be set by a relatively simple process. This can reduce the processing load and improve the inspection efficiency.

[0014] Furthermore, according to the above-mentioned means 1, the determining means calculates the area of ​​the part having a brightness equal to or higher than a predetermined brightness threshold in each inspection area, and determines the application state of the flux based on the calculated area. That is, since ultraviolet light is absorbed by the flux and reflected by the electrodes, the flux becomes a dark area in the captured image and the electrodes become a bright area, and the area of ​​the electrodes not covered by the flux (which should be covered by the flux) is calculated as the area of ​​the part having a brightness equal to or higher than the brightness threshold. Then, the application state of the flux is inspected based on the area of ​​the part having a brightness equal to or higher than the brightness threshold (the area of ​​the electrodes not covered by the flux). Therefore, the application state of the flux can be inspected not for each of the electrodes corresponding to one component, but for all of these electrodes collectively. Therefore, it is possible to obtain good inspection accuracy while setting a relatively rough inspection area. As a result, even when inspecting a board on which a plurality of electrodes are provided at an extremely small pitch (for example, a board on which a BGA is mounted), sufficient inspection accuracy can be ensured.

[0015] Means 2. The flux application state inspection device according to Means 1, characterized in that the wavelength of the ultraviolet light irradiated from the irradiating means is set to 100 nm or more and 300 nm or less.

[0016] According to the above-mentioned means 2, since ultraviolet light is more easily absorbed in the flux, the flux can be made darker in the captured image. Therefore, the difference between the brightness of the electrodes and the brightness of the flux can be made larger in the captured image, and the flux and the electrodes can be more accurately identified. This makes it possible to further improve the inspection accuracy.

[0017] In order to further improve the inspection accuracy, the wavelength of the ultraviolet light is more preferably 200 nm or more and 300 nm or less, even more preferably 220 nm or more and 280 nm or less, and most preferably 230 nm or more and 260 nm or less.

[0018] Means 3. The imaging means is disposed above the substrate so that its optical axis is perpendicular to the substrate; The flux application state inspection device according to Means 1, characterized in that the angle of incidence of the ultraviolet light irradiated from the irradiating means to the board is set to be between 0° and 30°.

[0019] According to the above-mentioned means 3, the ultraviolet light reflected by the electrodes can reach the imaging means more easily, so that the difference between the brightness of the electrodes and the brightness of the flux in the captured image can be made larger. As a result, the flux and the electrodes can be more accurately identified in the captured image, and the inspection accuracy can be further improved.

[0020] Furthermore, in terms of further improving the inspection accuracy, it is more preferable that the incident angle of the ultraviolet light on the substrate be greater than or equal to 0° and less than or equal to 20°, even more preferable that it be greater than or equal to 0° and less than or equal to 15°, and most preferable that it be greater than or equal to 0° and less than or equal to 10°.

[0021] Means 4: The flux application state inspection device according to Means 1, which is used to inspect transparent or translucent flux.

[0022] Since the irradiation means irradiates ultraviolet light instead of visible light, even if the flux is transparent or semitransparent as in the above-mentioned means 4, the flux can be shown as a dark area in the captured image. Therefore, even if the flux to be inspected is transparent or semitransparent, the application state of the flux can be inspected with high accuracy.

[0023] Means 5. The flux application state inspection device according to Means 1, characterized in that it is used to inspect flux applied to electrodes of a glass epoxy board as the board.

[0024] According to the above-mentioned means 5, the electrodes and the substrate (particularly the substrate) are more easily differentiated in the captured image, and the area of ​​the bright part (electrode) can be more accurately specified. This can further improve the inspection accuracy.

[0025] Means 6. A flux application state inspection method for inspecting flux that is applied to an electrode of a substrate and is capable of absorbing ultraviolet light, comprising the steps of: an irradiation step of irradiating the substrate with ultraviolet light; an imaging step of imaging the ultraviolet light irradiated onto the substrate; an inspection area setting step of setting, for each component, an inspection area on the board that corresponds to the component to be mounted and includes a plurality of electrodes on which the component is to be mounted, using a reference portion provided on the board as a reference; and a judging step of judging whether or not the flux application state is good based on an image obtained by imaging the ultraviolet light irradiated onto the inspection area in the imaging step while irradiating the inspection area with ultraviolet light in the irradiation step, The flux application state inspection method is characterized in that in the judgment step, an area of ​​a portion in each of the inspection regions having a luminance equal to or greater than a predetermined luminance threshold is calculated, and the flux application state is judged based on the calculated area.

[0026] According to the sixth aspect, the same effects as those of the first aspect can be achieved.

[0027] The technical matters related to the above-mentioned respective means may be combined as appropriate. Therefore, for example, the technical matters related to the above-mentioned means 2 may be combined with the technical matters related to the above-mentioned means 4. Moreover, at least one of the technical matters related to the above-mentioned means 2 to 5 may be applied to the above-mentioned means 6. [Brief description of the drawings]

[0028] [Figure 1] FIG. 2 is a schematic plan view of a printed circuit board. [Diagram 2] FIG. 2 is a schematic plan view of a printed circuit board with electronic components and the like omitted in order to show electrodes. [Diagram 3] FIG. 2 is a partially enlarged schematic cross-sectional view of a printed circuit board. [Figure 4] FIG. 2 is a schematic perspective view of an electronic component. [Diagram 5] FIG. 4 is a partially enlarged cross-sectional view showing an electronic component and the like before being mounted on an electrode. [Figure 6] FIG. 1 is a block diagram showing a configuration of a manufacturing line for printed circuit boards. [Figure 7] FIG. 2 is a partially enlarged schematic plan view of a printed circuit board showing flux applied to electrodes, etc. [Figure 8] FIG. 1 is a schematic diagram showing a flux application state inspection device; [Figure 9] FIG. 2 is a block diagram showing a functional configuration of a flux inspection state inspection device. [Figure 10] FIG. 1 is a partially enlarged schematic plan view of a printed circuit board in which all of the electrodes constituting an electrode group are appropriately and collectively covered with flux; [Figure 11] FIG. 2 is a schematic diagram showing a luminance image in a case where all of a plurality of electrodes constituting one electrode group are appropriately and collectively covered with flux. [Figure 12] 1 is a partially enlarged schematic plan view of a printed circuit board in which some of the electrodes are not properly covered with flux and are exposed. FIG. [Figure 13] 13 is a schematic diagram showing a luminance image in a case where some of the electrodes are not properly covered with flux and are exposed. FIG. [Figure 14] 13 is a partially enlarged schematic plan view of a printed circuit board in a configuration in which a plurality of electrodes are individually covered with flux, and some of the electrodes are not properly covered and are exposed. FIG. [Figure 15] 13 is a schematic diagram showing a luminance image in a configuration in which a plurality of electrodes are individually covered with flux, and some of the plurality of electrodes are not properly covered and are exposed. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] An embodiment will be described below with reference to the drawings. First, the configuration of a printed circuit board as a "substrate" will be described.

[0030] As shown in Figures 1 to 3, printed circuit board 1 (hereinafter simply referred to as "board 1") is a so-called glass epoxy board, in which electrodes 3 (not shown in Figure 1) made of copper foil are formed on a flat base substrate 2 made of glass epoxy resin or the like. Electronic components 5 such as chips are mounted on electrodes 3 via solder 4 made of solder particles kneaded with flux. In this embodiment, electronic components 5 correspond to "components".

[0031] The area of ​​the base substrate 2 other than the electrodes 3 and the circuit pattern (electrode pattern) is a base portion 6 made of glass epoxy resin, resist, or the like, and is green in this embodiment.

[0032] Furthermore, as shown in FIG. 4, the electronic component 5 in this embodiment is a so-called ball grid array (BGA) having a plurality of bumps 4a regularly arranged on its bottom surface. Each bump 4a melts in a reflow process in a reflow device 14 described later and spreads over the surface of the electrode 3, eventually forming the solder 4. The base substrate 2 has an electrode group 3x (see FIG. 2) consisting of a plurality of electrodes 3 on which each bump 4a of one electronic component 5 is to be mounted, and when mounting the electronic component 5 on the base substrate 2, each bump 4a is mounted on each electrode 3 constituting the electrode group 3x. The base substrate 2 also has a plurality of (for example, four) electrode groups 3x, and one electronic component 5 is mounted on each electrode group 3x. In this embodiment, the pitch of the plurality of electrodes 3 constituting one electrode group 3x is very small (for example, 1.8 mm or less or 0.5 mm or less).

[0033] 5, before electronic components 5 are mounted on the electrode groups 3x, flux 7 is applied in advance to the surface of the base substrate 2 including the surfaces of the electrode groups 3x (electrodes 3). The flux 7 is used to remove metal oxide films on the electrodes 3, electronic components 5, and solder 4, and to enhance the wettability of the solder 4. The flux 7 is capable of absorbing ultraviolet light, and is transparent or semi-transparent and difficult to see. Furthermore, in this embodiment, the flux 7 does not cover each of the electrodes 3 constituting one electrode group 3x individually, but covers all of these electrodes 3 collectively.

[0034] In addition, the base substrate 2 is provided with a mark 8 for identifying the mounting position of the electronic component 5 (see FIGS. 1 and 2). The mark 8 is provided in a portion of the base substrate 2 that is not covered with the flux 7, and is also used to identify an inspection region KR, which will be described later. In this embodiment, the mark 8 corresponds to the "reference portion." Note that a predetermined electrode 3, a circuit pattern (electrode pattern), a printed portion, etc. may also be used as the "reference portion."

[0035] Next, a description will be given of the manufacturing line (manufacturing process) for manufacturing the board 1. As shown in Fig. 6, the manufacturing line 10 is provided with, in order from the upstream side (upper side in Fig. 6), a flux application device 11, a flux application state inspection device 12, a component mounter 13, a reflow device 14, and a post-reflow inspection device 15. The board 1 is set up to be transported to these devices in this order.

[0036] The flux applicator 11 applies the flux 7 to at least the surface of the electrode 3 on the substrate 1. For example, the flux applicator 11 places a predetermined mask on the substrate 1 and then applies the flux 7 to the surface of the electrode 3 by using screen printing. Of course, the flux applicator 11 may also be one that applies the flux 7 by using a predetermined dispenser.

[0037] Furthermore, as shown in Fig. 7, the flux application device 11 applies the flux 7 so as to collectively cover a plurality of electrodes 3 constituting one electrode group 3x. Figs. 7, 10, 12, and 14 are partial enlarged schematic plan views of the substrate 1, and in these drawings, the flux 7 is shaded for convenience of illustration. However, since the flux 7 is transparent or semi-transparent, in reality, it is not easy to clearly see the application area of ​​the flux 7 by visual inspection.

[0038] The flux application state inspection device 12 is for inspecting the application state of the flux 7 applied to the electrode 3. The flux application state inspection device 12 will be described later.

[0039] The component mounter 13 performs a component mounting process (mounting process) of mounting the electronic component 5 on the electrodes 3, etc. As a result, the electronic component 5 is placed on the electrode group 3x via the bumps 4a.

[0040] The reflow device 14 performs a reflow process for heating and melting the bumps 4a, etc. In the substrate 1 that has undergone the reflow process, the bumps 4a melt and spread over the surfaces of the electrodes 3, and finally solidify to become the solder 4. Then, the electrodes 3 and the electronic components 5 are joined by the solder 4.

[0041] The post-reflow inspection device 15 performs a post-reflow inspection process to inspect whether or not the solder joint has been properly performed in the reflow process. For example, the post-reflow inspection device 15 inspects whether or not there is any misalignment in the electronic components 5 using image data of the board 1 after the reflow process.

[0042] In addition, although not shown in the figures, the manufacturing line 10 is provided with conveyors or the like for transporting the board 1 between the above-mentioned devices, such as between the flux application device 11 and the flux application state inspection device 12. Also, branching devices are provided between the flux application state inspection device 12 and the component mounter 13 and downstream of the post-reflow inspection device 15. The board 1 determined to be a non-defective product by the flux application state inspection device 12 or the post-reflow inspection device 15 is guided directly downstream, while the board 1 determined to be a defective product by at least one of the inspection devices 12, 15 is discharged by the branching device to a defective product storage section (not shown).

[0043] Next, a description will be given of the configuration of the flux application state inspection device 12. As shown in Fig. 8 and Fig. 9, the flux application state inspection device 12 includes a transport mechanism 31 which transports and positions the substrate 1, an inspection unit 32 which inspects the flux 7, and a control device 33 which controls the driving of the transport mechanism 31 and the inspection unit 32, as well as performs various controls, image processing, and arithmetic processing in the inspection device 12.

[0044] The transport mechanism 31 includes a pair of transport rails 31a arranged along the direction in which the substrate 1 is carried in and out, and an endless conveyor belt 31b rotatably disposed on each of the transport rails 31a. Although not shown, the transport mechanism 31 also includes a driving means such as a motor for driving the conveyor belt 31b, and a chuck mechanism for positioning the substrate 1 at a predetermined position. The transport mechanism 31 is driven and controlled by a control device 33 (a transport mechanism control unit 338 described later).

[0045] Under the above configuration, the board 1 carried into the flux coating state inspection device 12 has both side edges in the width direction perpendicular to the carrying-in / out direction inserted into the conveyor rails 31a, and is placed on the conveyor belt 31b. Then, the conveyor belt 31b starts to operate, and the board 1 is carried to a predetermined inspection position. When the board 1 reaches the inspection position, the conveyor belt 31b stops and the chuck mechanism is operated. The operation of this chuck mechanism pushes up the conveyor belt 31b, and both side edges of the board 1 are clamped by the conveyor belt 31b and the upper side of the conveyor rail 31a. This positions and fixes the board 1 at the inspection position. When the inspection is completed, the fixation by the chuck mechanism is released and the conveyor belt 31b starts to operate. This causes the board 1 to be carried out of the flux coating state inspection device 12. Of course, the configuration of the conveyor mechanism 31 is not limited to the above embodiment, and other configurations may be adopted.

[0046] The inspection unit 32 is disposed above the transport rail 31a (the transport path for the substrate 1) and includes an illumination device 321 and a camera 322. In this embodiment, the illumination device 321 constitutes an "illumination means" and the camera 322 constitutes an "imaging means."

[0047] The inspection unit 32 also includes an X-axis movement mechanism 323 that allows movement in the X-axis direction (left-right direction in FIG. 8) and a Y-axis movement mechanism 324 that allows movement in the Y-axis direction (front-back direction in FIG. 8). Both movement mechanisms 323, 324 are driven and controlled by the control device 33 (a movement mechanism control unit 337 described later).

[0048] The lighting device 321 irradiates ultraviolet light onto the board 1 to be inspected by the flux application state inspection device 12. The wavelength of the ultraviolet light irradiated from the lighting device 321 is set to 100 nm or more and 300 nm or less. The wavelength of the ultraviolet light is more preferably 200 nm or more and 300 nm or less, even more preferably 220 nm or more and 280 nm or less, and most preferably 230 nm or more and 260 nm or less.

[0049] Furthermore, the lighting device 321 irradiates the substrate 1 with light from vertically above or obliquely above. The incidence angle θ of the ultraviolet light from the lighting device 321 to the substrate 1 (particularly the inspection area) is set to be 0° or more and 30° or less. It is more preferable that the incidence angle θ be 0° or more and 20° or less, even more preferable that it be 0° or more and 15° or less, and most preferable that it be 0° or more and 10° or less. In this embodiment, the process of irradiating the substrate 1 with ultraviolet light from the lighting device 321 corresponds to the "irradiation process".

[0050] The camera 322 is disposed directly above the board 1 to be inspected with its optical axis O perpendicular to the board 1, and captures an image of a predetermined inspection area KR (an area surrounded by a rectangle formed by a two-dot chain line in FIG. 7 and the like) on the board 1 from directly above. In this embodiment, the inspection area KR is set for each electronic component 5 to be mounted, and is an area that includes all of the multiple electrodes 3 that make up one electrode group 3x. The inspection area KR is set by an inspection area setting unit 335, which will be described later.

[0051] The camera 322 is composed of a CCD camera or the like having sensitivity to the ultraviolet light irradiated from the lighting device 321, and its operation is controlled by the control device 33 (camera control unit 333 described later). Under the operation control of the control device 33, the camera 322 captures an image of the ultraviolet light reflected from the substrate 1 in the inspection region KR while the substrate 1 is being irradiated with ultraviolet light from the lighting device 321. This allows a luminance image of the inspection region KR to be acquired. The luminance image includes a large number of pixels, each of which has data related to luminance. In this embodiment, the process of using the camera 322 to capture an image of the ultraviolet light irradiated from the lighting device 321 and reflected from the substrate 1 corresponds to an "imaging process". The luminance image corresponds to a "captured image".

[0052] In addition, when all of the electrodes 3 constituting one electrode group 3x are appropriately covered collectively with the flux 7 (see, for example, FIG. 10), the electrodes 3 do not appear in the inspection region KR in the luminance image, and the flux 7 appears as a dark area (see, for example, FIG. 11). On the other hand, when a part or all of the electrodes 3 are not appropriately covered with the flux 7, and an exposed electrode 3e that is an exposed electrode 3 exists (see, for example, FIG. 12), the exposed electrode 3e appears as a bright area in the inspection region KR in the luminance image (see, for example, FIG. 13). In addition, in a configuration in which the electrodes 3 are individually covered with the flux 7, when a part of the electrodes 3 is not appropriately covered and an exposed electrode 3e exists (see, for example, FIG. 14), the exposed electrode 3e also appears as a bright area in the inspection region KR in the luminance image (see, for example, FIG. 15).

[0053] The luminance image acquired by the camera 322 is transferred to the control device 33 (an image acquisition unit 334 described below). The control device 33 executes an inspection process regarding the application state of the flux 7 based on the luminance image.

[0054] The control device 33 consists of a computer including a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a ROM (Read Only Memory) that stores various programs and fixed value data, a RAM (Random Access Memory) that temporarily stores various data when executing various arithmetic processing, and peripheral circuits thereof.

[0055] The control device 33 functions as various functional units, such as a main control unit 331, a lighting control unit 332, a camera control unit 333, an image acquisition unit 334, an inspection area setting unit 335, a judgment unit 336, a movement mechanism control unit 337, and a transport mechanism control unit 338, by the CPU operating in accordance with various programs.

[0056] However, the above-mentioned various functional units are realized by cooperation of various hardware such as the above-mentioned CPU, ROM, RAM, etc., and it is not necessary to clearly distinguish between functions realized by hardware and functions realized by software, and some or all of these functions may be realized by a hardware circuit such as an IC. In this embodiment, the inspection area setting unit 335 constitutes the "inspection area setting means", and the determination unit 336 constitutes the "determination means".

[0057] Furthermore, the control device 33 is provided with an input unit 340 consisting of a keyboard, mouse, touch panel, etc., a display unit 341 having a display screen consisting of a liquid crystal display, etc., a memory unit 342 capable of storing various data, programs, calculation results, inspection results, etc., a communication unit 343 capable of transmitting various data to and receiving from the outside, etc. First, the memory unit 342 and the communication unit 343 will be described.

[0058] The storage unit 342 is configured with a storage device such as a hard disk drive (HDD) or a solid state drive (SSD), and stores various information. The storage unit 342 includes an image storage unit 342a, an inspection information storage unit 342b, and an inspection result storage unit 342c.

[0059] The image storage unit 342a stores the luminance image captured and acquired by the camera 322. The image stored in the image storage unit 342a can be displayed on the display unit 341 as appropriate.

[0060] The inspection information storage unit 342b stores various information used in inspecting the flux 7. For example, the inspection information storage unit 342b stores various thresholds used when binarizing a luminance image or determining whether the flux 7 is good or bad, design data, manufacturing data, etc. The design data and manufacturing data include a planned application area of ​​the flux 7, a size of the flux 7 in an ideal application state (e.g., an area of ​​the flux 7, a contour length, etc.), a mounting area of ​​the electronic component 5, etc.

[0061] The inspection result storage unit 342c stores inspection result data relating to the application state of the flux 7 by the determination unit 336. The inspection result storage unit 342c also stores statistical data obtained by statistically processing the inspection result data. These inspection result data and statistical data can be displayed on the display unit 341 as appropriate.

[0062] The communication unit 343 includes a communication interface conforming to a communication standard such as a wired LAN (Local Area Network) or a wireless LAN, and is configured to be able to transmit and receive various data to and from the outside. For example, the result of the inspection performed by the determination unit 336 is output to the outside via the communication unit 343, and the result of the inspection performed by the post-reflow inspection device 15 is input via the communication unit 343.

[0063] Next, a detailed description will be given of the above-mentioned various functional units constituting the control device 33. First, the movement mechanism control unit 337 and the transport mechanism control unit 338 will be described, and then the main control unit 331 and the like will be described.

[0064] The movement mechanism control unit 337 is a functional unit that drives and controls the X-axis movement mechanism 323 and the Y-axis movement mechanism 324, and controls the position of the inspection unit 32 based on a command signal from the main control unit 331. The movement mechanism control unit 337 drives and controls the X-axis movement mechanism 323 and the Y-axis movement mechanism 324, thereby moving the inspection unit 32 to a position above any inspection region KR on the substrate 1 that is positioned and fixed at the inspection position. Then, the inspection unit 32 is moved sequentially to a plurality of inspection regions KR set on the substrate 1, and inspections related to the inspection regions KR are performed, thereby performing inspections of the flux 7 in all of the inspection regions KR.

[0065] The transport mechanism control unit 338 is a functional unit that controls the drive of the transport mechanism 31 , and controls the transport position of the substrate 1 based on a command signal from the main control unit 331 .

[0066] Next, a description will be given of the main control unit 331 etc. The main control unit 331 is a functional unit that controls the entire flux application state inspection device 12, and is configured to be able to transmit and receive various signals to and from other functional units such as a lighting control unit 332 and a camera control unit 333.

[0067] The illumination control unit 332 is a functional unit that controls the driving of the illumination device 321. Based on a command signal from the main control unit 331, the illumination control unit 332 performs timing control regarding the start and end of irradiation of light from the illumination device 321 to the substrate 1.

[0068] The camera control unit 333 is a functional unit that drives and controls the camera 322. The camera control unit 333 controls the timing of the imaging operation in the camera 322 based on a command signal from the main control unit 331.

[0069] The image capture unit 334 is a functional unit for capturing a luminance image captured and acquired by the camera 322. The luminance image captured by the image capture unit 334 is stored in the image storage unit 342a.

[0070] The inspection area setting unit 335 sets an inspection area KR for each electronic component 5 based on the mark 8 provided on the board 1. In this embodiment, the inspection area setting unit 335 sets an inspection area KR corresponding to the area to be coated with the flux 7. More specifically, the inspection area setting unit 335 grasps the area to be coated with the flux 7 based on the predetermined mark 8 provided on the board 1 and the design data and manufacturing data stored in the inspection information storage unit 342b, and sets the inspection area KR from the grasped area to be coated. In this embodiment, the inspection area KR is a region one size larger than the area to be coated with the flux 7, and is set to an area including all the electrodes 3 to be coated with the flux 7. In this embodiment, the process of setting the inspection area KR by the inspection area setting unit 335 corresponds to the "inspection area setting process". The inspection area KR may be set based on the mounting area of ​​the electronic component 5 on the design data and manufacturing data.

[0071] The determination unit 336 inspects the flux 7 applied to the substrate 1. More specifically, the determination unit 336 first obtains a binary image by performing a binarization process on the luminance image based on the threshold value stored in the inspection information storage unit 342b. In the binary image, the portion corresponding to the flux 7 becomes a dark portion (0), and the portion corresponding to the electrode 3 that is not covered with the flux 7 and is exposed to the outside becomes a bright portion (1).

[0072] Next, the determination unit 336 performs a process of identifying connected components of pixels corresponding to bright areas in the binarized image, and calculates the area (number of pixels in this embodiment) of each identified connected component (clump portion). As a result, the determination unit 336 calculates the area of ​​the portion not covered by the flux 7 in each of the multiple electrodes 3 constituting the electrode group 3x.

[0073] Then, the determination unit 336 compares the calculated area of ​​the lump portion with an area threshold pre-stored in the inspection information storage unit 342b. If the area of ​​at least one lump portion is equal to or greater than the area threshold, the determination unit 336 determines that the application of the flux 7 to at least one electrode 3 is insufficient and determines the application state of the flux 7 to be "poor". On the other hand, if the areas of all the lump portions are below the area threshold, the determination unit 336 determines that the flux 7 is properly applied to the multiple electrodes 3 constituting one electrode group 3x and determines the application state of the flux 7 to be "good".

[0074] Then, the judgment unit 336 performs the above-mentioned judgment on all the inspection regions KR, and when the judgment unit 336 judges the application state of the flux 7 to be "bad" in at least one of the inspection regions KR, the judgment unit 336 judges the substrate 1 to be inspected to be "bad" in terms of the application state of the flux 7. On the other hand, when the judgment unit 336 performs the above-mentioned judgment on all the inspection regions KR and judges the application state of the flux 7 to be "good" in all the inspection regions KR, the judgment unit 336 judges the substrate 1 to be inspected to be "good" in terms of the application state of the flux 7. The pass / fail judgment result (inspection result data) is stored in the inspection result storage unit 342c. In this embodiment, the process of the judgment unit 336 making a pass / fail judgment on the application state of the flux 7 corresponds to the "judgment process".

[0075] As described above in detail, according to this embodiment, the inspection area setting unit 335 does not set each individual electrode 3 as an inspection area, but sets one inspection area KR corresponding to a plurality of electrodes 3 on which one electronic component 5 is to be mounted. Therefore, since it is sufficient to set the inspection area KR relatively roughly, the inspection area KR can be set by a relatively simple process. This can reduce the processing load and improve the inspection efficiency.

[0076] Furthermore, the determination unit 336 calculates the area of ​​a portion (bright connected component) having a luminance equal to or greater than a predetermined luminance threshold in each inspection region KR, and determines the application state of the flux 7 based on the calculated area. Therefore, the application state of the flux 7 can be inspected not for each of a plurality of electrodes 3 corresponding to one electronic component 5, but for all of these electrodes 3 collectively. This makes it possible to obtain good inspection accuracy while setting a relatively rough inspection region KR. As a result, sufficient inspection accuracy can be ensured even when inspecting a board 1 on which a plurality of electrodes 3 are provided at an extremely small pitch (for example, a board on which a BGA is mounted).

[0077] Furthermore, since the wavelength of the ultraviolet light irradiated from the illumination device 321 is set to 100 nm or more and 300 nm or less, the ultraviolet light is more easily absorbed by the flux 7. Therefore, in the luminance image, the flux 7 can be made darker, and the difference between the luminance of the electrode 3 and the luminance of the flux 7 can be made larger. This allows the flux 7 and the electrode 3 to be identified more accurately, and the inspection accuracy can be further improved.

[0078] Furthermore, since the incident angle θ of the ultraviolet light irradiated from the lighting device 321 to the substrate 1 is set to be equal to or greater than 0° and equal to or less than 30°, the ultraviolet light reflected by the electrode 3 is more likely to reach the imaging means. Therefore, the difference between the brightness of the electrode 3 and the brightness of the flux 7 in the brightness image can be made even larger. As a result, it is possible to more accurately identify the flux 7 and the electrode 3 in the brightness image, and the inspection accuracy can be further improved.

[0079] In addition, since the illumination device 321 irradiates ultraviolet light instead of visible light, even if the flux 7 is transparent or semitransparent, the flux 7 can be displayed as a dark area in the luminance image. Therefore, even if the flux 7 to be inspected is transparent or semitransparent, the application state of the flux 7 can be inspected with high accuracy.

[0080] In addition, since the substrate 1 is a glass epoxy substrate, the electrodes 3 and the substrate 1 (particularly the base portion 6) are more easily differentiated in the brightness image, and the area of ​​the bright portion (electrodes 3) can be more accurately identified. This further improves the inspection accuracy.

[0081] The present invention is not limited to the above-described embodiment, and may be implemented as follows: Of course, other applications and modifications not exemplified below are also possible.

[0082] (a) In the above embodiment, the determination unit 336 calculates the area of ​​the portions of the multiple electrodes 3 constituting the electrode group 3x that are not covered with the flux 7. Alternatively, the determination unit 336 may calculate the total area of ​​the portions of the electrodes 3 that are not covered with the flux 7. The determination unit 336 may then compare the calculated total area with an area threshold to determine whether the application state of the flux 7 is good or bad.

[0083] (b) In the above embodiment, the substrate 1 is a glass epoxy substrate, but it may be another type of substrate, such as a ceramic substrate.

[0084] (c) In the above embodiment, the flux 7 is transparent or translucent, but it may also be opaque.

[0085] In the above embodiment, the flux 7 is configured to collectively cover all of the electrodes 3 constituting one electrode group 3x, but it may also be configured to cover these electrodes 3 individually.

[0086] (d) In the above embodiment, a BGA is given as the electronic component 5, but the electronic component 5 may be another semiconductor package (for example, a CSP (Chip Size Package)). [Explanation of symbols]

[0087] 1...printed circuit board (circuit board), 3...electrode, 5...electronic component (component), 7...flux, 12...flux application state inspection device, 321...illumination device (illumination means), 322...camera (imaging means), 335...inspection area setting section (inspection area setting means), 336...judgment section (judgment means), KR...inspection area.

Claims

1. A flux application state inspection device for inspecting flux that is applied to an electrode of a substrate and is capable of absorbing ultraviolet light, comprising: An irradiation means capable of irradiating the substrate with ultraviolet light; an imaging means capable of imaging the ultraviolet light irradiated onto the substrate; an inspection area setting means for setting, for each component, an inspection area on the board that corresponds to a component to be mounted and includes a plurality of electrodes on which the component is to be mounted, using a reference portion provided on the board as a reference; a determination unit that performs a quality determination on a state of application of the flux based on an image obtained by imaging the ultraviolet light irradiated onto the inspection area by the imaging unit while irradiating the ultraviolet light onto the inspection area by the irradiation unit, the determining means is configured to calculate an area of ​​a portion in each of the inspection regions having a luminance equal to or greater than a predetermined luminance threshold, and to determine the state of flux application based on the calculated area.

2. 2. The flux application state inspection device according to claim 1, wherein the wavelength of the ultraviolet light irradiated from said irradiating means is set to be 100 nm or more and 300 nm or less.

3. the imaging means is disposed above the substrate such that its optical axis is perpendicular to the substrate; 2. The flux application state inspection device according to claim 1, wherein an incident angle of the ultraviolet light irradiated from said irradiating means onto said board is set to be in the range of 0° to 30°.

4. 2. The flux application state inspection device according to claim 1, which is used for inspecting transparent or semi-transparent flux.

5. 2. The flux application state inspection device according to claim 1, which is used to inspect flux applied to electrodes of a glass epoxy substrate as the substrate.

6. A flux application state inspection method for inspecting flux that is applied to an electrode of a substrate and is capable of absorbing ultraviolet light, comprising the steps of: an irradiation step of irradiating the substrate with ultraviolet light; an imaging step of imaging the ultraviolet light irradiated onto the substrate; an inspection area setting step of setting, for each component, an inspection area on the board that corresponds to the component to be mounted and includes a plurality of electrodes on which the component is to be mounted, using a reference portion provided on the board as a reference; and a judging step of judging whether or not the application state of the flux is good based on an image obtained by imaging the ultraviolet light irradiated onto the inspection area in the imaging step while irradiating the inspection area with ultraviolet light in the irradiation step, The flux application state inspection method is characterized in that in the judgment step, an area of ​​a portion in each of the inspection regions having a luminance equal to or greater than a predetermined luminance threshold is calculated, and the flux application state is judged based on the calculated area.

Images