Inspection method for electronic component and inspection device for electronic component

Abstract

To provide an inspection method for an electronic component, in which the flatness of a dipole electrode of a surface mount type electronic component can be inspected by appearance inspection.SOLUTION: A first optical image that can detect a plane of a solder connection part of a first electrode and a plane of a solder connection part of a second electrode of an electronic component, and a second optical image that can detect the plane of the solder connection part of the first electrode and the plane of the solder connection part of the second electrode at an angle different from the angle of the first optical image are acquired. From at least one of the first optical image and the second optical image, the relative position between the plane of the solder connection part of the first electrode and the plane of the solder connection part of the second electrode of the electronic component is calculated. Then, by calculating the flatness of the first electrode and the second electrode, the quality of the appearance of the electronic component is determined.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an electronic component inspection method and an electronic component inspection device. [Background technology]

[0002] In the manufacturing process of small electronic components such as diodes, visual inspection currently relies on the visual work of inspectors. As a result, tasks such as distinguishing between normal and defective electronic components and detecting defects are performed using human senses. In response to this, a technique has been proposed in which electronic components before being mounted on a board are observed with a camera and image processing technology is used to detect defects in appearance. For example, a method has been disclosed in which, for axial lead-type electronic components, multiple cameras are arranged around the object to be inspected so that the optical axis of the optical system used for observation is 90° or less or 180° or less, and bends in the lead wires are automatically detected by image processing (see, for example, Patent Document 1). Also, for rectangular parallelepiped electronic components such as wafer chips, an optical system configuration has been disclosed for inspecting the appearance of the front, back, and side surfaces of the object in a short time (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-159732 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-128781 Summary of the Invention [Problem to be solved by the invention]

[0004] In surface-mount electronic components, dimensional errors in the flatness of the two poles (anode and cathode) soldered onto the mounting board directly lead to mounting defects. However, the inspection method described in Patent Document 1 targets axial-lead electronic components and can only evaluate the coaxiality or parallelism of the two lead wires, and is not applicable to inspecting electronic components with other configurations, including the flatness of surface-mount diode elements. Furthermore, the inspection method described in Patent Document 2 only images the electronic component to be inspected and performs a visual inspection for cracks, chips, scratches, etc., and does not mention inspecting the flatness of the electrodes of surface-mount electronic components.

[0005] In order to solve the above-mentioned problems, the present invention provides an electronic component inspection method and an electronic component inspection device that can inspect the flatness of two electrodes of a surface-mounted electronic component by visual inspection.

[0006] The above and other objects of the present invention and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0007] An electronic component inspection method according to the present invention inspects an electronic component having first and second electrodes surface-mounted on a substrate. This inspection method acquires a first optical image capable of detecting the planes of the solder connections of the first and second electrodes of the electronic component, and a second optical image capable of detecting the planes of the solder connections of the first and second electrodes at an angle different from that of the first optical image. Then, from at least one of the first and second optical images, the relative position between the planes of the solder connections of the first and second electrodes of the electronic component is calculated, and the flatness of the first and second electrodes is calculated to determine the quality of the appearance of the electronic component.

[0008] An electronic component inspection device of the present invention inspects an electronic component having a first electrode and a second electrode surface-mounted on a substrate, and includes a transport device that transports the electronic component to an observation position, an imaging device that captures a first optical image capable of detecting the planes of the solder connections of the first electrode and the second electrode of the electronic component, and a second optical image at an angle different from the angle of the first optical image, capable of detecting the planes of the solder connections of the first electrode and the second electrode, an observation optical system disposed between the electronic component and the imaging device, and a device controller that controls the transport device and the imaging device. The device control unit has an image analysis unit that analyzes information in at least one of the first optical image and the second optical image acquired by the imaging device and calculates the relative position between the plane of the solder connection portion of the first electrode of the electronic component and the plane of the solder connection portion of the second electrode, and an inspection unit that compares the flatness of the solder connection portion of the first electrode and the solder connection portion of the second electrode with a threshold value based on the information calculated by the image analysis unit. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an electronic component inspection method and an electronic component inspection device that are capable of inspecting the flatness of two electrodes of a surface-mounted electronic component by visual inspection.

[0010] Problems, configurations, and effects other than those described above will become clear from the following description of the embodiments. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing the configuration of a surface-mounted diode element, which is an example of an electronic component. [Figure 2] FIG. 1 is a cross-sectional view of a surface-mounted diode element, which is an example of an electronic component. [Figure 3] 10A and 10B are diagrams showing an example of a diode element whose flatness has deteriorated due to an assembly defect. [Figure 4] FIG. 1 is a perspective view showing a configuration of an inspection device for electronic components. [Figure 5]FIG. 2 is a functional block diagram of a device control unit of the inspection device. [Figure 6] 1 is a flowchart of an inspection method for electronic components. [Figure 7] 10 is a diagram for explaining the difference in inclination θy between the soldered connection portion of the lead and the soldered connection portion of the base. FIG. [Figure 8] 10 is a diagram for explaining the step [Zb-Zt] in the z-axis direction between the soldered connection portion of the lead and the soldered connection portion of the base. FIG. [Figure 9] FIG. 10 is a diagram showing an optical image (yz side view) of a diode element detected by a camera. [Figure 10] FIG. 10 is a bottom view (xy plan view) of the solder connection portion of the base of the diode element. [Figure 11] 10 is a diagram for explaining the displacement of the height of a point P on the outer periphery of a solder connection portion. FIG. [Figure 12] FIG. 10 is a diagram showing the configuration of an inspection device in a state where a diode element is positioned within an observation field. [Figure 13] 13 is an xz cross-sectional view of a prism in the observation optical system of the inspection device shown in FIG. 12. [Figure 14] FIG. 10 is a diagram showing an optical image of a diode element captured by a camera in an inspection device. DETAILED DESCRIPTION OF THE INVENTION

[0012] An example of an electronic component inspection method and an electronic component inspection device according to an embodiment of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following example. In the drawings described below, common components are given the same reference numerals. Furthermore, in the drawings used in this specification, identical or corresponding components are given the same reference numerals, and repeated description of these components may be omitted.

[0013] [Electronic component configuration] First, the configuration of an electronic component to be inspected using the electronic component inspection method and electronic component inspection device of this embodiment will be described. The electronic component to be inspected in this embodiment is, for example, a small electronic component such as a diode product. Small electronic components are mass-produced at a monthly production scale of several million units. Small electronic components come in a wide variety of product types and have a variety of component shapes. Furthermore, because small electronic components are small and lightweight (weighing a few grams), it is difficult to inexpensively build a mechanism for transporting and positioning individual electronic components. For these reasons, automating the visual inspection process for electronic components is considered difficult. In the following description, a product in which a semiconductor element is housed in a dedicated package and configured to be attached to a mounting board as an electronic component will be referred to as a "diode element" or simply an "element."

[0014] 1 and 2 show, as an example of an electronic component, a surface-mounted diode element, which is a type of Zener diode and is used for surge absorption. FIG. 1 is an external view of the diode element, and FIG. 2 is a cross-sectional view of the diode element. In the diode element 100 shown in FIG. 1, a plan view is shown as diode element 100a, side views are shown as diode elements 100b and 100c, and a bottom view is shown as diode element 100d.

[0015] The diode element 100 has two electrodes: a base 101 (first electrode) and a lead 102 (second electrode). The diode element 100 is a surface-mounted electronic component, and the two electrodes (anode and cathode) of the base 101 and the lead 102 are soldered onto a mounting board. The base 101 corresponds to the anode of the diode element 100, and the lead 102 corresponds to the cathode of the diode element 100. Both the base 101 and the lead 102 are made of metal. The outer diameter 101a of the base 101 is about 10 mm. The diode element 100 weighs only about 2 g per element, and is easily deformed if handled improperly.

[0016] Base 101 is formed in the shape of a case with a bottom and an opening at the top. Semiconductor element 110 is built into base 101. Inside base 101, the bottom surface of semiconductor element 110 is electrically connected to the bottom surface on the inner surface of base 101 by means of 111b. The top surface of the semiconductor element 110 is electrically connected to the metal electrode 103 by solders 111a and 111b. The metal electrode 103 is electrically connected to the lead 102 by a ring solder 112 having an annular shape. The inside of the base 101 is filled with insulating resin 104. The insulating resin 104 seals the entire semiconductor element 110 and the metal electrodes 103 except for the portions connected to the ring solder 112.

[0017] The lead 102 has a crank-like shape in which straight metal sections are alternately bent at approximately 90°. The lead 102 has an adsorption portion 102a for contacting a suction nozzle (not shown) when transporting the diode elements 100 individually, and a terminal portion 102b for mounting (soldering) on ​​a printed circuit board (not shown). The adsorption portion 102a, the terminal portion 102b, and the portion connecting them are each formed in a straight line (flat). Furthermore, the adsorption portion 102a and the terminal portion 102b are formed so as to be parallel to each other. Furthermore, the lead 102 is electrically connected to the semiconductor element 110 via a ring solder 112 at the end of the suction portion 102a.

[0018] The rear surface of the terminal portion 102b is the solder connection portion 102c when mounting on the printed circuit board. Therefore, the connection portion 102c has an area large enough to allow connection by soldering, and is formed as a substantially flat surface. The bottom of the outer surface of the base 101 is a solder connection portion 101b, similar to the connection portion 102c on the rear surface of the terminal portion 102b. Therefore, the connection portion 101b has an area large enough to allow connection by soldering, and is formed as a substantially flat surface. In order to reliably mount diode element 100 on a printed circuit board, it is desirable that the flat surfaces of solder connection portions 101b and 102c are flush with each other. However, deviation from the flush surface of solder connection portions 101b and 102c is permitted within a predetermined tolerance range that does not impair the mounting reliability of diode element 100 on the board.

[0019] 2, in the diode element 100, the base 101 and the semiconductor element 110, the semiconductor element 110 and the metal electrode 103, and the metal electrode 103 and the lead 102 are connected by solders 111a, 111b, and 112, respectively. Therefore, if poor leveling occurs during the reflow process of the solders 111a, 111b, and 112, the flatness between the solder connection portion 101b of the base 101 and the adsorption portion 102a of the lead 102 deteriorates. In other words, the flatness between the solder connection portion 101b of the base 101 and the solder connection portion 102c of the lead 102 deteriorates.

[0020] 3 shows an example of the configuration of a diode element 100 in which the flatness between the solder connection portion 101b of the base 101 and the solder connection portion 102c of the lead 102 has deteriorated due to an assembly error. FIG. 3(a) shows the diode element 100 in an xz plane view, and FIG. 3(b) shows the diode element 100 in a yz plane view. In the diode element 100 shown in FIG. 3, the z-axis is a direction perpendicular to the surface of a substrate when the diode element 100 is mounted on the substrate. For example, when the plane of the solder connection portion 101b of the base 101 and the plane of the solder connection portion 102c of the lead 102 are the same horizontal plane, the z-axis is a direction perpendicular to the plane of the solder connection portion 101b and the solder connection portion 102c. The x-axis is perpendicular to the z-axis and is the direction in which the lead 102 extends, i.e., parallel to the line connecting the center of the suction portion 102a of the lead 102 to the center of the terminal portion 102b. The y-axis is perpendicular to the z-axis and x-axis. The definition of the x-axis, y-axis, and z-axis for the diode element 100 is the same in all figures other than FIG. 3.

[0021] In FIG. 3, when taking the adsorption part 102a of the lead 102 as a reference, it shows a state where the base 101 is inclined by θy in the xz plane due to assembly errors or the like. As shown in FIG. 3(a), in the diode element 100, one end in the x-axis direction of the flat part of the solder connection part 101b of the base 101 is defined as P1, and the other end is defined as P2. At this time, when the diameter (P1 - P2) of the solder connection part 101b of the base 101 is 7 mm and the difference in inclination θy between the y-axis and the plane of the solder connection part 101b in the y-axis direction is 1°, a difference of 122 μm occurs in the height (z-axis direction) between P1 and P2. At this time, in the yz plane view of the diode element 100 shown in FIG. 3(b), a step G occurs in the z-axis direction between the end P2 of the solder connection part 101b of the base 101 and the plane of the solder connection part 102c of the lead 102. Therefore, the solder connection part 101b of the base 101 and the solder connection part 102c of the lead 102 cannot be regarded as the same plane. As a result, when mounting the diode element 100 on the printed circuit board, due to the step between the solder connection part 101b of the base 101 and the solder connection part 102c of the lead 102, at least one of the electrodes floats from the substrate. For this reason, a bonding failure between the substrate and the diode element is generated. Thus, in the diode element 100, the dimensional error in the flatness of the two-pole electrodes directly leads to mounting defects and becomes a factor for reducing reliability.

[0022] The diode element 100 is mainly used in rectifier circuits. Also, the diode element 100 is widely used in protection circuits for protecting electronic circuits from sudden electrical noise. Further, the diode element 100 is mounted and operated in advanced driving assistance systems and complex operation control systems in automobiles and railway vehicles, and higher reliability is required so that their important functions are not lost due to electrical noise. Therefore, for the diode element 100, it is important to ensure the reliability of the electrical characteristics of the single element, and the accurate mounting (solder connection) of the element on the mounting substrate is a condition for ensuring the performance of the entire circuit system.

[0023] [Electronic component inspection device (1)] Next, the configuration of the inspection apparatus for electronic components according to the present embodiment will be described. In the description of the inspection apparatus, the above-described diode element 100 is used as the electronic component to be inspected. FIG. 4 is a perspective view showing the configuration of the inspection apparatus for electronic components.

[0024] The inspection apparatus 200 shown in FIG. 4 inspects the relative positions between the solder connection portion 101b of the base 101 and the solder connection portion 102c of the lead 102, which are between two electrode surfaces of the diode element 100, and determines good products and defective products in a short time. The inspection apparatus 200 includes observation lenses 220 and 221, cameras 230 and 231, surface illuminators 210 and 211, and a suction nozzle 243. Further, the inspection apparatus 200 includes an illumination control unit 241, a transport mechanism 242, and an image processing unit 240 that control the above configuration. Furthermore, the inspection apparatus 200 includes an apparatus control unit 250 that comprehensively controls each of the above configurations. The observation lenses 220 and 221 are an example of an observation optical system that guides the optical image of the diode element 100. The cameras 230 and 231 are an example of an imaging device that acquires the optical image of the diode element 100. The suction nozzle 243 is an example of a transport device for transporting the diode element 100 to a predetermined observation position. Also, the surface illuminators 210 and 211 are an example of an illumination device that adjusts the brightness of the diode element 100 when acquiring an optical image.

[0025] The apparatus control unit 250 is composed of, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., not shown in the figure. The CPU is an example of an arithmetic unit related to the inspection apparatus 200. The CPU centrally controls the operations of each part of the inspection apparatus 200. The CPU reads out the program codes of software related to various processes of the inspection apparatus 200 stored in the ROM (an example of a recording medium) and expands them in the RAM. Then, the CPU controls the inspection apparatus 200 according to the expanded program. Note that the apparatus control unit 250 may include another arithmetic device such as an MPU (Micro Processing Unit) as an arithmetic unit instead of the CPU.

[0026] The inspection device 200 vacuum-sucks the suction portion 102a of the diode element 100 with the suction nozzle 243 and positions it at an observation position within the field of view of the observation lenses 220 and 221. The operation of the suction nozzle 243 is controlled by a transport mechanism 242. The transport mechanism 242 is a device that moves the suction nozzle 243 in the horizontal and vertical directions. The transport mechanism 242 controls the operation of the suction nozzle 243 based on the control of the device control unit 250. The transport mechanism 242 is made up of a power source such as a motor or actuator for operating the suction nozzle 243, a pump for vacuum-sucking the diode element 100, and various members for transmitting these powers to the suction nozzle 243.

[0027] In the inspection device 200, the observation lenses 220 and 221 that constitute the observation optical system are arranged at positions where the observation optical axes 220' and 221' are orthogonal to each other in the xy plane. Then, the side surfaces (as viewed from the xz plane and the yz plane) of the diode element 100 are detected by the cameras 230 and 231 along the observation optical axes 220' and 221'. The surface illuminators 210 and 211 are arranged at positions facing the observation lenses 220 and 221 across the diode element 100. The normals 210' and 211' of the light-emitting surfaces of the surface illuminators 210 and 211 are coaxial with the optical axes 220' and 221'. The lighting control unit 241 controls the illuminance and lighting timing of the surface illuminators 210 and 211 based on the control of the device control unit 250 .

[0028] Furthermore, image capture control of cameras 230 and 231 is performed by image processing unit 240 based on control of device control unit 250. Image processing unit 240 controls activation, image capture, etc. of cameras 230 and 231. Furthermore, image processing unit 240 takes in image information captured by cameras 230 and 231, and performs processes such as conversion, deformation, analysis of specific information, and extraction of specific information on the acquired image information.

[0029] (Functional configuration of the device control unit) Next, a description will be given of the functional configuration of device control unit 250. A functional block diagram of device control unit 250 is shown in FIG. The transfer control unit 251 controls the driving of the transfer mechanism 242. As a result, the transfer control unit 251 controls the operation of the suction nozzle 243 via the transfer mechanism 242, and performs suction, transfer, and positioning of the diode element 100.

[0030] The imaging control unit 252 controls the driving of the surface illuminator 210 and the driving of the cameras 230 and 231. The imaging control unit 252 controls the turning on and off of the surface illuminator 210. Furthermore, the imaging control unit 252 controls the driving of the cameras 230 and 231, thereby controlling the acquisition of an optical image of the diode element 100. Furthermore, the imaging control unit 252 outputs image data acquired by the cameras 230 and 231 to the image processing unit 240.

[0031] The image analysis unit 253 acquires the image of the diode element 100 created by the image processing unit 240. Then, the image analysis unit 253 analyzes information in the acquired image based on predetermined image processing parameters. For example, the image analysis unit 253 extracts a specific area for analysis from the acquired image. Then, the image analysis unit 253 detects the positions of various components in the extracted image, converts them into mathematical expressions, quantifies them, and performs other calculations.

[0032] The inspection unit 254 compares the various components of the diode element 100 with a standard for determining whether the diode element 100 is a good product, based on the detection, mathematical expression, and digitization of the positions of the various components calculated by the image analysis unit 253. For example, the inspection unit 254 determines the step value of the solder connection portion 101b and the solder connection portion 102c of the diode element 100 acquired from the image as the flatness of the bipolar electrodes, and compares it with a threshold value for the step value for determining whether the diode element 100 is a good product. The inspection unit 254 also determines the value of the inclination difference θy of the plane of the solder connection portion 101b as the flatness of the bipolar electrodes, and compares it with a threshold value for the inclination value for determining whether the diode element 100 is a good product. Furthermore, the inspection unit 254 also determines the value of the flatness of the solder connection portion 101b as the flatness of the bipolar electrodes, and compares it with a threshold value for the flatness value for determining whether the diode element 100 is a good product.

[0033] The determination unit 255 determines whether the appearance of the inspected diode element 100 is a pass or not. Specifically, the determination unit 255 determines whether the appearance of the diode element 100 is a pass or not based on the result of comparing the values ​​of various components of the diode element 100 inspected by the inspection unit 254 with a threshold value for determining whether the diode element 100 is a pass or not. If all the results of the inspection by the inspection unit 254 are within the threshold value, the determination unit 255 determines the diode element 100 to be a pass or not. If at least one of all the results of the inspection by the inspection unit 254 exceeds the threshold value, the determination unit 255 determines the diode element 100 to be a defective product.

[0034] 4, the transport mechanism 242, the illumination control unit 241, and the image processing unit 240 are shown as components separate from the device control unit 250, but some or all of these may be included in the device control unit 250. For example, the device control unit 250 may include the image processing unit 240, and the image processing by the image processing unit 240 may be performed by the device control unit 250. Alternatively, the device control unit 250 may include the illumination control unit 241, and the illumination control processing by the illumination control unit 241 may be performed by the device control unit 250. Furthermore, the device control unit 250 may include an internal control function of the transport mechanism 242, and the device control unit 250 may control the operation of the suction nozzle 243 by the transport mechanism 242.

[0035] [Inspection methods for electronic components] Next, an electronic component inspection method using the above-described inspection device will be described. A flowchart of the electronic component inspection method is shown in Fig. 6. The flowchart shown in Fig. 6 is an explanatory diagram of the operation of inspection device 200. Furthermore, diode element 100 to be inspected is taken out from a group of diode elements stored in a tray (not shown).

[0036] First, the transport control unit 251 drives the transport mechanism 242 and the suction nozzle 243 to pick up the diode elements 100 one by one from the tray (step S300). Then, the suction nozzle 243 is moved along the transport path 201 to position the picked-up diode elements 100 at desired observation positions within the imaging areas of the cameras 230 and 231 (step S301).

[0037] Next, the imaging control unit 252 turns on the surface illuminator 210 and causes the camera 230 to capture an image, thereby detecting an optical image (xz side view; first optical image) of the diode element 100 (step S302). The imaging control unit 252 also turns on the surface illuminator 211 and causes the camera 231 to capture an image, thereby detecting an optical image (yz side view; second optical image) of the diode element 100 (step S303). Steps S302 and S303 are preferably performed simultaneously. The observation lenses 220 and 221 each incorporate an illumination mechanism (not shown) coaxial with the observation optical axes 220' and 221'. Therefore, the imaging control unit 252 controls the illumination mechanisms of the observation lenses 220 and 221 to be turned on simultaneously with the surface illuminators 210 and 211 disposed opposite the observation lenses 220 and 221.

[0038] Next, based on the optical image (xz side view), the inspection unit 254 determines whether the step [Zb-Zt] in the z-axis direction between a straight line 411 (Figure 7) parallel to the plane of the solder connection portion 101b and the plane of the solder connection portion 102c is within a threshold value (first threshold value) (step S304). If the step difference [Zb-Zt] is within the threshold value (Yes in step S304), the inspection unit 254 determines whether the difference in inclination θy between the y-axis and the plane of the solder connection portion 101b in the y-axis direction is within a threshold value (second threshold value) (step S305).

[0039] The step [Zb-Zt] in the z-axis direction between straight line 411 (FIG. 7) and solder connection portion 102c in step S304, and the tilt difference θy of solder connection portion 101b in step S305 will be described with reference to FIGS. 7 and 8. FIGS. 7 and 8 show an optical image (xz side view) of diode element 100 detected by camera 230 in step S302. FIG. 7 is a diagram showing the entire detection field of camera 230. FIG. 8 is an enlarged view of the periphery of terminal portion 102b.

[0040] 7, the image analysis unit 253 acquires an image (xz side view) of the diode element 100 created by the image processing unit 240. Then, the image analysis unit 253 extracts the range of an area 400 that is predetermined by image processing parameters and includes the solder connection portion 101b of the base 101. Furthermore, the image analysis unit 253 calculates a straight line 411 that is parallel to the plane of the solder connection portion 101b of the base 101 in the image of the extracted area 400.

[0041] 8, the image analysis unit 253 extracts the range of an area 401 that is predetermined by the image processing parameters and that includes the bottom surface (solder connection portion 102c) of the terminal portion 102b of the lead 102. Furthermore, the image analysis unit 253 calculates a straight line 410 that is parallel to the plane of the solder connection portion 102c of the lead 102 in the image of the extracted area 401.

[0042] Then, the image analysis unit 253 defines the center position of the region 401 on the x-axis on the straight line 410 as the height Zt of the solder connection part 102c in the z-axis direction. Furthermore, the image analysis unit 253 defines the position on the straight line 411 that is closest to the position where the height Zt is defined as the height Zb of the straight line 411 in the z-axis direction.

[0043] Next, inspection unit 254 calculates the difference (step) between height Zt of solder connection 102c in the z-axis direction and height Zb of straight line 411 in the z-axis direction using the formula [Zb-Zt]. Furthermore, inspection unit 254 determines whether the calculated step [Zb-Zt] is within a predetermined threshold value (first threshold value) that has been set in advance. The above is the processing of the image analysis unit 253 and the inspection unit 254 in step S304.

[0044] Next, the image analysis unit 253 detects the difference in inclination θy of the line 411 parallel to the plane of the solder connection portion 101b of the base 101, with reference to the line 410 parallel to the plane of the solder connection portion 102c of the lead 102. As a result, the image analysis unit 253 calculates the difference in inclination θy of the line 411 parallel to the plane of the solder connection portion 101b of the base 101, with respect to the line 410 parallel to the plane of the solder connection portion 102c of the lead 102. Then, the inspection unit 254 determines whether the tilt difference θy calculated by the image analysis unit 253 is within a predetermined threshold value (second threshold value) that has been set in advance. The above is the processing of the image analysis unit 253 and the inspection unit 254 in step S305.

[0045] Returning to the explanation of FIG. 6, if the difference in inclination θy is within the threshold value (Yes in step S305), the inspection unit 254 determines whether the flatness of the solder connection portion 101b of the base 101 is within a threshold value (third threshold value) (step S306). A method for calculating the flatness of the solder connection portion 101b of the base 101 in step S306 will be described with reference to Fig. 9 and Fig. 10. Fig. 9 shows an optical image (yz side view) of the diode element 100 detected by the camera 231 in step S303. Fig. 10 shows a bottom view (xy plan view) of the solder connection portion 101b of the base 101 of the diode element 100.

[0046] 9, the image analysis unit 253 acquires an image (yz side view) of the diode element 100 created by the image processing unit 240. Then, the image analysis unit 253 extracts the range of an area 500 that is predetermined by the image processing parameters and includes the bottom surface (solder connection portion 102c) of the terminal portion 102b of the lead 102. Furthermore, the image analysis unit 253 calculates a straight line 510 that is parallel to the plane of the solder connection portion 102c of the lead 102 in the image of the extracted area 500.

[0047] 9, image analysis unit 253 extracts ranges of region 501 and region 502, which are predetermined by image processing parameters and include solder connection portion 101b of base 101. Furthermore, image analysis unit 253 calculates straight line 511, which is parallel to the plane of solder connection portion 101b of base 101, in the images of extracted region 501 and region 502.

[0048] Next, the image analysis unit 253 detects the difference in inclination θx of the line 511 parallel to the plane of the solder connection portion 101b of the base 101, with respect to the line 510 parallel to the plane of the solder connection portion 102c of the lead 102. As a result, the image analysis unit 253 calculates the difference in inclination θx of the line 511 parallel to the plane of the solder connection portion 101b of the base 101, with respect to the line 510 parallel to the plane of the solder connection portion 102c of the lead 102.

[0049] Next, the image analysis unit 253 calculates the flatness of the solder connection portion 101b using the difference in slope θx between the line 510 and the line 511, and the difference in slope θy between the line 410 and the line 411. The image analysis unit 253 calculates the flatness of the solder connection portion 101b using the plane of the solder connection portion 102c as a reference. FIG. 10 shows a bottom view of the diode element 100. As shown in FIG. 10, the radius of the solder connection portion 101b is defined as r, and the height of an arbitrary point P on its periphery is calculated. If the amount of variation in the height of the point P due to the influence of the slope difference θy in the x-z cross section shown in FIG. 7 is Z1, and the amount of variation in the height of the point P due to the influence of the slope difference θx in the y-z cross section shown in FIG. 9 is Z2, Z1 and Z2 can be calculated using equations (1) and (2), respectively.

[0050] Z1=r·cosφ·tanθy (1) Z2=r·sinφ·tanθx (2)

[0051] The height of point P on the outer periphery of solder connection 101b is affected by the slope differences θy and θx, and takes the value of [Z1 + Z2]. FIG. 11 is an explanatory diagram showing the variation in height of point P on the outer periphery of solder connection 101b. As shown in FIG. 11, the flatness of solder connection 101b is calculated as the difference between the maximum and minimum values ​​of [Z1 + Z2]. Note that FIG. 11 shows the results of calculations under the conditions of radius r of solder connection 101b = 4 mm, θy = 0.8° in the x-z cross section, and θx = -0.5° in the y-z cross section. In the above example, the flatness of solder connection 101b is calculated to be 132 μm. The above is the calculation process of the flatness of the solder connection portion 101b of the base 101 in step S306.

[0052] Returning to the explanation of Figure 6, if the step [Zb-Zt] is not within the threshold value (No in step S304), if the difference in slope θy is not within the threshold value (No in step S305), or if the flatness of the solder connection portion 101b is not within the threshold value (No in step S306), the judgment unit 255 identifies the inspected diode element 100 as a defective product (step S307). For example, in step S304, if the distance from the center of the metal electrode 103 to the point Zt is L=10 mm and θy=1°, the step difference is calculated as [Zb-Zt=175 μm]. If the step difference [Zb-Zt] threshold 1 is set to ±100 μm, the determination unit 255 will identify a diode element 100 with a step difference of "Zb-Zt=175 μm" as a defective product. Furthermore, in the above step S305, if the tilt difference is calculated to be [θy=-2°] and the tilt difference [θy] threshold value 2 is set to ±1°, the judgment unit 255 will identify the diode element 100 with the tilt difference [θy=-2°] as a defective product. Furthermore, if the threshold value for flatness is set to 100 μm in step S306, the determining unit 255 will identify the diode element 100 whose flatness is calculated to be 132 μm under the above conditions as a defective product.

[0053] If the flatness of the solder connection portion 101b is within the threshold value (No in step S306), or after identifying the diode element 100 as a defective product, the transport control unit 251 drives the transport mechanism 242 and the suction nozzle 243 to move the inspected diode element 100 from the observation position (step S308). The transport control unit 251 drives the transport mechanism 242 and the suction nozzle 243 to take out the next diode element to be inspected from the tray and transport it to the observation position.

[0054] Next, the determination unit 255 determines whether the appearance of the diode element 100 after the inspection is a pass product (step S309). The determination unit 255 determines that the appearance of the diode element 100 determined not to be within the threshold in any of steps S304, S305, and S306 is a pass product. If the appearance of the diode element 100 is non-defective (Yes in step S309), the transport control unit 251 sorts the non-defective diode element 100 for shipping (step S310). If the appearance of the diode element 100 is not good (No in step S309), the transport control unit 251 collects the defective diode element 100 into a collection box (step S311). After the diode elements 100 are sorted for shipping or collected, the process according to this flowchart ends.

[0055] According to the above-described electronic component inspection method, two cameras 230, 231 with orthogonal observation fields capture images of the same inspection target, diode element 100. Then, the relative positional relationship between solder connection 101b on the base 101 side and solder connection 102c on the lead 102 side is detected from each captured image. This allows the step, inclination, and flatness between solder connection 101b and solder connection 102c to be calculated from the two optical images. As a result, visual inspection of diode element 100 can be performed in a short time without using three-dimensional measurement, and 10 ...

[0056] In the above-described electronic component inspection method, images of the diode element 100 are acquired from the xz side view and the yz side view, but the images to be acquired are not limited to these positions. As described above, the images to be acquired are preferably the xz side view shown in FIG. 7 and the yz side view shown in FIG. 9, but the imaging angle of the diode element 100 is not particularly important. In the electronic component inspection method, it is necessary to capture images of the diode element 100 from two different angles at a position where at least the plane of the solder connection portion 101b and the plane of the solder connection portion 102c of the diode element 100 can both be recognized. Then, from the planes of solder connection portion 101b and solder connection portion 102c of diode element 100 in one of the captured images, straight line 410 parallel to the plane of solder connection portion 102c and straight line 411 parallel to the plane of solder connection portion 101b are calculated. Furthermore, from the planes of solder connection portion 101b and solder connection portion 102c of diode element 100 in the other captured image, straight line 510 parallel to the plane of solder connection portion 102c and straight line 511 parallel to the plane of solder connection portion 101b are calculated. Therefore, in the electronic component inspection method, it is sufficient to acquire two images taken from an xy plane that is perpendicular to the z-axis and parallel to solder joints 101b and 102c. By acquiring images from this position, the planes of solder joints 101b and 102c can be extracted and analyzed more accurately.

[0057] Furthermore, in the above-described electronic component inspection method, three types of comparison judgments, namely, steps S304, S305, and S306, are performed to determine whether an electronic component is acceptable, but it is not necessary to perform all of these. In the electronic component inspection method, it is sufficient to perform the pass / fail judgment of an electronic component using at least one of the comparison judgment methods in steps S304, S305, and S306. It is preferable to use at least the comparison judgment method in step S304, due to its ease of image analysis and calculation and high inspection accuracy. It is also preferable to combine the comparison judgment method in step S304 with one or more of the judgment methods in steps S305 and S306.

[0058] [Electronic component inspection equipment (2)] Next, another configuration of the electronic component inspection apparatus according to this embodiment will be described. Fig. 12 shows the configuration (perspective view) of another form of electronic component inspection apparatus. The inspection apparatus 200A shown in Fig. 12 includes a telecentric lens 600, a camera 610, prisms 601, 602, 603, and 604, and suction nozzles 243 and 244. Similar to the inspection apparatus 200 shown in Fig. 4 described above, the inspection apparatus 200A also includes an illumination control unit 241 that controls the configuration, a transport mechanism 242, an image processing unit 240, and an apparatus control unit 250 that performs overall control of each component.

[0059] In the inspection device 200A, an observation optical system is configured by prisms 601, 602, 603, and 604, and a telecentric lens 600. In the inspection device 200A, the telecentric lens 600 has an aperture diameter that encompasses observation areas 601', 602', 603', and 604' obtained by the prisms 601, 602, 603, and 604. Therefore, in the inspection device 200A, the optical image detected by the telecentric lens 600 via the prisms 601, 602, 603, and 604 can be observed by a camera 610.

[0060] The inspection device 200 sucks the diode elements 100 and 100A with suction nozzles 243 and 244, and transports and positions them in the observation field at regular time intervals. FIG. 12 shows the state in which the diode element 100 is positioned within the observation field. Four prisms 601, 602, 603, and 604, each having the same shape and a 45° angle at its tip, are arranged facing each other around the diode element 100. Therefore, the diode element 100 is moved horizontally along a transport path 620 by a transport mechanism (not shown) to the top of the observation field, where it stops, and then descends along a transport path 621 in the -z axis direction. This positions the diode element 100 in the desired observation field within the imaging area of ​​the camera 610. Furthermore, after the optical image is captured, the diode element 100 is raised by a transport mechanism (not shown) along a transport path 622 in the +z-axis direction, moved horizontally along a transport path 623, and removed from the observation field of view. Simultaneously with the removal operation of the diode element 100, the next diode element 100A is transported and positioned in the observation field of view.

[0061] The inspection device 200A observes the side surface of the diode element 100 from four directions using prisms 601, 602, 603, and 604 arranged opposite to each other. Fig. 13 is an xz cross-sectional view of the prisms 602 and 604 of the observation optical system shown in Fig. 12. Note that the suction nozzle 244 is not shown in Fig. 13. By disposing the diode element 100 between the opposing prisms 602 and 604, the inspection device 200A can observe the yz side surface of the diode element 100 with the camera 610 via the prisms 602 and 604 and the telecentric lens 600. At the same time, the inspection device 200A can directly observe the bottom surface (xy bottom surface) of the diode element 100 with the camera 610 via the telecentric lens 600.

[0062] Fig. 14 shows an optical image of the diode element 100 captured by the camera 610 in the above-described inspection apparatus 200A. As shown in Fig. 14, an xy plan view (bottom surface) of the diode element 100 is obtained in the center of the field of view. In addition, a yz side view of the diode element 100 is obtained in observation areas 602' and 604', and an xz side view of the diode element 100 is obtained in observation areas 601' and 603'.

[0063] Therefore, the inspection device 200A can use the optical image of the observation area 601' or the observation area 603' to calculate the step difference (Zb-Zt) between the solder connection portion 101b of the base 101 and the solder connection portion 102c of the lead 102 shown in Fig. 8. Furthermore, the inspection device 200A can use the optical image of the observation area 601' or the observation area 603' to calculate the tilt difference θy of the plane of the solder connection portion 101b of the base 101 with respect to the solder connection portion 102c of the lead 102. Furthermore, using the optical image of the observation area 602', the difference in inclination θx between a line 511 parallel to the plane of the solder connection portion 101b of the base 101 and a line 510 parallel to the plane of the solder connection portion 102c of the lead 102 shown in Figure 7 can be calculated.

[0064] According to the above-described electronic component inspection device, multiple prisms 601, 602, 603, and 604 are arranged around the diode element 100 to be inspected, and the same diode element 100 to be inspected is simultaneously observed from multiple directions. This allows five optical images of the four side surfaces and the bottom surface of the diode element 100 to be acquired from a single acquired image data. The relative positional relationship between the solder connection 101b on the base 101 side and the solder connection 102c on the lead 102 side is then detected from each observation region. This makes it possible to calculate the step, inclination, and flatness of the solder connection 101b and the solder connection 102c from a single image data. This allows for the miniaturization of the visual inspection optical system. Furthermore, with the above-described electronic component inspection device, five optical images of the four side surfaces and bottom surface of the diode element 100 are acquired, making it possible to inspect the surface of the diode element 100 being inspected for appearance defects such as scratches and discoloration.

[0065] It should be noted that the present invention is not limited to the above-described embodiments and various modifications are possible. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to an embodiment including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to delete part of the configuration of each embodiment, or to add or replace other configurations. [Explanation of symbols]

[0066] 100, 100a, 100b, 100d, 100A diode element, 101 base, 101a outer diameter, 101b, 102c solder connection portion, 102 lead, 102a suction portion, 102b terminal portion, 103 metal electrode, 104 insulating resin, 110 semiconductor element, 200, 200A inspection device, 201, 620, 621, 622, 623 transport path, 210, 211 surface illuminator, 210' normal, 220 observation lens, 220' observation optical axis, 230, 231, 610 camera, 240 image processing unit, 241 lighting control unit, 242 transport mechanism, 243, 244 suction nozzle, 250 device control unit, 251 transport control unit, 252 imaging control unit, 253 Image analysis unit, 254 Inspection unit, 255 Judgment unit, 400, 401, 500, 50, 502 Area, 410, 411, 510, 511 Line, 600 Telecentric lens, 601, 602, 603, 604 Prism, 601', 602', 603', 604' Observation area

Claims

1. A method for inspecting an electronic component having a first electrode and a second electrode surface-mounted on a substrate, comprising: acquiring a first optical image capable of detecting the plane of the solder connection portion of the first electrode and the plane of the solder connection portion of the second electrode of the electronic component, and a second optical image capable of detecting the plane of the solder connection portion of the first electrode and the plane of the solder connection portion of the second electrode at an angle different from an angle of the first optical image; calculating a relative position between a plane of the solder connection portion of the first electrode of the electronic component and a plane of the solder connection portion of the second electrode of the electronic component from at least one of the first optical image and the second optical image; The flatness of the first electrode and the second electrode is calculated to determine whether the appearance of the electronic component is good or bad. Inspection methods for electronic components.

2. calculating, based on the first optical image, a step difference [Zb-Zt] between a height Zb of the plane of the solder connection portion of the first electrode in the z-axis direction and a height Zt of the solder connection portion of the second electrode in the z-axis direction as the flatness of the first electrode and the second electrode; The step [Zb-Zt] is compared with a first threshold value to determine whether the appearance of the electronic component is good or bad. The method for inspecting electronic components according to claim 1 .

3. calculating, based on the first optical image, a difference in inclination θy of the plane of the solder connection portion of the first electrode in the y-axis direction with respect to a straight line parallel to the plane of the solder connection portion of the second electrode, as the flatness of the first electrode and the second electrode; The difference in inclination θy is compared with a second threshold value to determine whether the appearance of the electronic component is good or bad. The method for inspecting electronic components according to claim 1 .

4. The flatness of the first electrode and the second electrode is calculating a difference in inclination θy in the y-axis direction of the plane of the solder connection portion of the first electrode with respect to a straight line parallel to the plane of the solder connection portion of the second electrode based on the first optical image; calculating a difference in inclination θx in the x-axis direction of the plane of the solder connection portion of the first electrode with respect to a straight line parallel to the plane of the solder connection portion of the second electrode based on the second optical image; calculating the flatness of the plane of the solder connection portion of the first electrode based on the tilt difference θx and the tilt difference θy; The flatness of the surface of the solder connection portion of the first electrode is compared with a third threshold value to determine whether the appearance of the electronic component is good or bad. The method for inspecting electronic components according to claim 1 .

5. An inspection device for an electronic component having a first electrode and a second electrode surface-mounted on a substrate, comprising: a transport device that transports the electronic component to an observation position; an imaging device that acquires a first optical image capable of detecting the plane of the solder connection portion of the first electrode and the plane of the solder connection portion of the second electrode of the electronic component, and a second optical image that can detect the plane of the solder connection portion of the first electrode and the plane of the solder connection portion of the second electrode at an angle different from the angle of the first optical image; an observation optical system disposed between the electronic component and the imaging device; a device control unit that controls the transport device and the imaging device, The device control unit an image analysis unit that analyzes information in at least one of the first optical image and the second optical image acquired by the imaging device and calculates a relative position between a plane of the solder connection portion of the first electrode of the electronic component and a plane of the solder connection portion of the second electrode; an inspection unit that compares the flatness of the solder connection portion of the first electrode and the solder connection portion of the second electrode with a threshold value based on the information calculated by the image analysis unit. Inspection equipment for electronic components.

6. The observation optical system includes four prisms arranged opposite to each other around the observation position of the electronic component, The imaging device uses the prism to capture the first optical image, the second optical image, the third optical image, and the fourth optical image of the side surface of the electronic component from four different angles. The electronic component inspection device according to claim 5.

Images