JP7731639B2 - Component inspection method, inspection device, and component mounting device - Google Patents

Description

The present invention relates to an inspection method and device for components such as package components with multiple leads (terminals), and a component mounting device equipped with this inspection device.

Component mounting devices are known for mounting (mounting) electronic components and other parts onto substrates such as printed wiring boards. Electronic components include packaged components with many leads, such as SOPs (Small Outline Packages) and QFPs (Quad Flat Packages). In these types of packaged components (hereinafter simply referred to as components), variations in the height of the joints (the tips of the leads that are joined to the substrate) can lead to poor contact between the substrate and the leads, ultimately resulting in the production of defective substrates. For this reason, component mounting devices inspect the coplanarity of the component joints before mounting the components on the substrate, and only components with good coplanarity are mounted on the substrate.

Patent Document 1 discloses a component mounting apparatus equipped with a device for inspecting the flatness of component joints (hereinafter sometimes simply referred to as flatness). In this component mounting apparatus, a component held by suction on a component transport head is imaged with a camera before being mounted on a board, and the flatness is determined based on the image. Specifically, the three-dimensional coordinates of multiple marks affixed to the underside of the component body (package) are detected. A least-squares plane is found from these three-dimensional coordinates and set as the reference plane. In other words, the underside of the component body (package) is set as the reference plane. The three-dimensional coordinates of the joints of each lead are then detected, and the flatness is determined based on the difference in elevation of the joints relative to the reference plane. More specifically, the difference between the maximum and minimum heights from the reference plane to the joints is found, and the flatness is determined by comparing this difference with a threshold value.

JP 2018-98404 A

The component mounting device in Patent Document 1 requires multiple marks on the underside of the component body as a prerequisite for flatness inspection, making it difficult to inspect the flatness of components that do not have marks.

Therefore, for components that do not have marks, a least-squares plane is calculated based on the three-dimensional coordinates of the joints of each lead (i.e., the least-squares plane of the joints is calculated), and this least-squares plane is used as the reference plane to determine the difference between the maximum and minimum values, thereby judging the flatness.

However, using the least-squares plane of the joint as the reference plane poses the following problem. Specifically, if only some of the lead joints are floating, the difference in height between the floating joints and the reference plane becomes significant. Therefore, in this case, it is possible to determine that the flatness is poor with relative accuracy. On the other hand, if the leads are deformed such that the heights of multiple leads (joints) on both sides of the SOP change linearly from one end to the other in the lead alignment direction, or if the heights of all leads (joints) on one side of the SOP are floating by a certain amount relative to the leads on the other side, the flatness may be determined to be good even if it is poor. This is because, when the least-squares plane of the joint is used as the reference plane, the reference plane is tilted along the joints, so there is no difference in height between the joints and the reference plane, or if there is a difference in height, the difference in height is generally small.

The present invention was made in consideration of the above circumstances, and aims to provide technology that enables more accurate determination of the flatness of joints for components such as package components with multiple leads (terminals).

In order to solve the above-mentioned problems, one aspect of the present invention provides a component inspection method for inspecting flatness of a component having a plurality of terminals, each having a joint to be joined to a substrate, the method including: a position detection step for detecting the position of the joint of each of the plurality of terminals; a reference plane setting step for determining a least-squares plane of the joint from position data detected in the position detection step and setting this least-squares plane as a reference plane; and a flatness judgment step for finally judging the flatness by combining a first mode for judging the flatness based on the difference in elevation between the reference plane and the joint of each terminal, and a second mode for judging the flatness based on the difference in elevation of the joints of two predetermined terminals that are spaced apart from each other, wherein the difference in elevation of the joints of the two spaced apart terminals in the second mode is the difference in elevation between positions on the reference plane that respectively correspond to the two terminals . In the above description, "use in combination" means that both the first mode and the second mode are prepared so that they can be executed, and at least one of the first mode and the second mode is executed during the judgment process, and a final judgment of whether the flatness is good or bad is made based on the results.

This inspection method uses both the first and second modes in the flatness determination process, enabling a more accurate determination of flatness. Specifically, the first mode determines flatness based on the difference in elevation between the joints and a reference plane (least-squares plane) determined from the positions of the joints of each of the multiple terminals. Therefore, if there is floating in the joints of some of the terminals, the first mode can be used to determine that the flatness is poor, just as in conventional methods.

On the other hand, the second mode is a mode in which the flatness is determined based on the difference in height between the joints of two spaced-apart terminals. For example, if terminal deformation occurs such that the height of multiple terminals (joints) changes linearly from one end to the other in the terminal arrangement direction, the difference in height between the joints of two spaced-apart terminals becomes significant. Therefore, the second mode, which determines the flatness of a part based on a predetermined difference in height between the joints of two spaced-apart terminals, makes it possible to determine whether the flatness is defective for parts with terminal deformation such as that described above, which is difficult to determine as defective in the first mode.

Therefore, the above inspection method, which combines the first and second modes, makes it possible to more accurately determine whether the flatness is good or bad.

In particular, in the second mode , the gradient of the reference plane is reflected in the height difference between the joints of the two terminals, making it possible to more reliably determine poor flatness when the terminals are deformed such that the height of the joint changes linearly from one end to the other in the terminal arrangement direction, or when the heights of all the terminals on one side are higher by a certain amount than the terminals on the other side.

In addition, in the flatness determination process, either the first mode or the second mode may be executed, and the other mode may be executed only if the flatness is determined to be good in the first mode. This method makes it possible to more accurately determine the flatness and to perform the determination efficiently.

Furthermore, in the above inspection method, if the component is a package component having a component body that is rectangular in plan view and the multiple terminals are arranged along opposing side surfaces of the component body, the second mode preferably includes a first determination step of determining whether the flatness is acceptable based on the difference in height between the joints of two of the multiple terminals that are spaced apart in the terminal arrangement direction.

This method makes it possible to determine whether a component has poor flatness when the height of the multiple terminals (joints) lined up on the side of the component body changes linearly from one end to the other in the terminal arrangement direction.

Furthermore, if the component is a package component as described above, the second mode preferably includes a second judgment step of judging the quality of the flatness based on the difference in height between the joints of the two terminals arranged on opposite sides of the component body.

This method makes it possible to determine whether a component has poor flatness when the height of all terminals (joints) on one side of the component body is higher than the terminals on the other side by a certain amount.

In the above-described inspection method, it is preferable that the flatness determining step determines that the flatness is good only when the flatness is determined to be good in both the first mode and the second mode. This method improves the reliability of the determination for a component whose flatness is determined to be good.
Another component inspection method according to one aspect of the present invention is a method for inspecting flatness of joints of a component having a plurality of terminals, each having a joint to be joined to a substrate, the method including: a position detection step for detecting the position of the joint of each of the plurality of terminals; a reference plane setting step for determining a least-squares plane of the joint from position data detected in the position detection step and setting this least-squares plane as a reference plane; and a flatness judgment step for finally judging the flatness by combining a first mode for judging the flatness based on the difference in elevation between the reference plane and the joint of each terminal, and a second mode for judging the flatness based on the difference in elevation of the joints of two predetermined terminals that are spaced apart from each other, wherein the component is a package component having a component body that is rectangular in plan view, and the plurality of terminals are arranged along opposing side surfaces of the component body, and the second mode includes a judgment step for judging the flatness based on the difference in elevation of the joints of the two terminals that are arranged on opposite sides of the component body.

On the other hand, a component inspection device according to one aspect of the present invention is an inspection device that inspects the flatness of a joint of a component having a plurality of terminals, each having a joint to be joined to a substrate, and includes: a position detection unit that detects the position of the joint of each of the plurality of terminals; and a judgment unit that judges whether the flatness is good or bad based on position data detected by the position detection unit, wherein the judgment unit executes a reference plane setting process that calculates a least-squares plane of the joint based on the position data and sets this least-squares plane as a reference plane; and a flatness judgment process that finally judges whether the flatness is good or bad by combining a first mode that judges whether the flatness is good or bad based on the difference in elevation between the reference plane and the joint of each terminal, and a second mode that judges whether the flatness is good or bad based on the difference in elevation of the joints of two predetermined terminals that are spaced apart from each other, wherein the difference in elevation of the joints of the two spaced apart terminals in the second mode is the difference in elevation between positions on the reference plane that correspond to the two terminals, respectively .

This inspection device makes it possible to automate inspection of component flatness based on the inspection method described above. That is, in this inspection device, a position detection unit detects the position of the joint of each of the multiple terminals, and based on that position data, a judgment unit executes a reference plane setting process and a flatness judgment process to judge whether the flatness is good or bad. In this case, the judgment unit uses both the first mode and the second mode in the flatness judgment process to make a final judgment on whether the flatness is good or bad. Therefore, it is possible to automate the inspection method described above and accurately judge whether the flatness is good or bad.

More specifically , the judgment unit is configured to execute either the first mode or the second mode in the flatness judgment process, and to execute the other mode only if the flatness is judged to be good in the one mode.

Furthermore, if the component is a package component having a component body that is rectangular in plan view and the multiple terminals are arranged along opposing side surfaces of the component body, the second mode includes a first determination step that determines the quality of the flatness based on the difference in height between the joints of two of the multiple terminals that are spaced apart in the terminal arrangement direction.

Furthermore, if the component is a package component, the second mode includes a second determination step of determining whether the flatness is good or bad based on the difference in height between the joints of the two terminals arranged on opposite sides of the component body.

In addition, the determination unit is configured to ultimately determine that the flatness is good only when the flatness is determined to be good in both the first mode and the second mode in the flatness determination process.
Another component inspection device according to one aspect of the present invention is an inspection device that inspects the flatness of a joint of a component having a plurality of terminals, each having a joint to be joined to a board, and includes a position detection unit that detects the position of the joint of each of the plurality of terminals, and a judgment unit that judges whether the flatness is good or bad based on position data detected by the position detection unit, and the judgment unit performs a reference plane setting process that finds a least-squares plane of the joint based on the position data and sets this least-squares plane as a reference plane, and judges whether the flatness is good or bad based on the height difference between the reference plane and the joint of each terminal. and a flatness determination process for finally determining whether the flatness is good or bad by combining a first mode for determining whether the flatness is good or bad, and a second mode for determining whether the flatness is good or bad based on the height difference of the joints of two predetermined terminals that are spaced apart from each other, wherein the component is a package component having a component body that is rectangular in a plan view, and the plurality of terminals are lined up along opposing side surfaces of the component body, and the second mode includes a determination step for determining whether the flatness is good or bad based on the height difference of the joints of the two terminals that are arranged on opposite sides of the component body.

Furthermore, one aspect of the present invention provides a component mounting device that uses a movable head to pick up components from a component supply unit, transport them onto a board, and mount the components on the board, wherein the components have multiple terminals, each having a joint that is joined to the board, and the component mounting device is characterized in that it includes any of the inspection devices described above as a device for inspecting the flatness of the joints of the components picked up by the head from the component supply unit.

In this component mounting device, the inspection device inspects the flatness of the joint of the component picked up by the head from the component supply unit. As described above, this inspection device performs a flatness determination process that uses both the first mode and the second mode to ultimately determine whether the flatness is good or bad. This makes it possible to accurately determine whether the flatness is good or bad, and ultimately to more effectively prevent components with poor flatness from being mounted on the board.

The present invention described above makes it possible to more accurately determine the pass/fail flatness of joints for components such as package components with multiple leads (terminals).

1 is a schematic diagram showing a main body of a component mounting apparatus according to the present invention; FIG. 2 is a schematic diagram of a component imaging camera. FIG. 1 is a perspective view of a part (SOP). FIG. 2 is a block diagram showing a control system of the component mounting apparatus. 10 is a flowchart showing control of flatness inspection processing. 6 is a flowchart (subroutine) of the process (flatness quality determination process) of step S7 in FIG. 5. FIG. 1 is an explanatory diagram of a lead of a component and a reference plane (least square plane). FIG. 10 is a side view of a component in which a lead is floating. FIG. 9 is a table showing the parts shown in FIG. 8 and the suitability of the determination mode. FIG. 1 is a perspective view of a part (QFP).

Embodiments of the present invention will be described in detail below with reference to the drawings.

[Configuration of device body 2 of component mounting device 1]
Fig. 1 is a schematic diagram showing the device body 2 of a component mounting device 1 according to the present invention. In Fig. 1, directional relationships are shown using an XYZ Cartesian coordinate system. The direction perpendicular to the plane of the paper in Fig. 1 is the X direction, the left-right direction on the plane of the paper is the Y direction, and the up-down direction on the plane of the paper is the Z direction.

The component mounting device 1 is a device that produces component-mounted boards, in which components are mounted (placed) on a substrate P, such as a printed wiring board, and includes a device main body 2 and a control unit 4 (see Figure 4).

The device main body 2 includes a mounting base (not shown), and on this base are a board transport mechanism 10, a component supply unit 12, a head 15, a head drive mechanism 16 (see Figure 4), and a component imaging camera 18.

The substrate transport mechanism 10 includes a belt-type conveyor 11 that extends, for example, in the X direction. The conveyor 11 transports the substrate P from outside the machine to a predetermined work position, and after the mounting operation, it transports it from the work position to outside the machine. The conveyor 11 is equipped with a clamping mechanism (not shown), which holds the substrate P at the work position during the mounting operation.

The component supply unit 12 is located to the side (Y direction side) of the board transport mechanism 10. The component supply unit 12 is equipped with a component supply device that supplies mounted components, and in this example, a tray feeder 13 is provided. The tray feeder 13 is a component supply device that supplies components 50 placed on a tray 13a. The tray 13a is a dish-shaped container for storing components that opens upward. This tray feeder 13 supplies components 50, such as so-called package components such as SOPs and QFPs, and connectors. Note that the component supply unit 12 may also be equipped with component supply devices other than the tray feeder 13, such as tape feeders or stick feeders that supply small surface-mount components (chip components).

Figure 3 is a perspective view of an SOP, one of the components 50 supplied by the tray feeder 13. The SOP comprises a component body (package) 51 that is rectangular in plan view, and multiple leads (terminals) 52 extending from each of its sides, specifically from the two long sides. That is, the SOP comprises lead rows (first lead row L1, second lead row L2) on each of two opposing sides of the component body 51, each row consisting of multiple leads 52. Each lead 52 has a crank-shaped bent shape and a joint 52a at its tip that is joined to the substrate P. The joint 52a is soldered to the circuit on the substrate P, thereby electrically joining the SOP to the substrate P. In the following description, unless otherwise noted, the component 50 refers to the SOP shown in Figure 3.

The head 15 is a tool that picks up a component 50 from the component supply unit 12 (tray feeder 13), moves it to a working position, and mounts the component on the substrate P. A nozzle 15a is provided at the tip of the head 15. Negative pressure and positive pressure are selectively supplied to this nozzle 15a, allowing the head 15 to suck and hold the component 50 and release the component 50 onto the substrate P.

The head drive mechanism 16 is a mechanism for moving the head 15 in the X, Y, Z, and R directions in the space above the component supply unit 12 and the substrate P at the work position. Movement in the R direction refers to rotation of the head 15 around a vertical axis. The head drive mechanism 16 moves the head 15 in each direction by driving a motor.

The component imaging camera 18 is positioned facing upward between the component supply unit 12 and the board transport mechanism 10. The component imaging camera 18 is an illuminated camera that captures images of the component 50 picked from the tray feeder 13 by the head 15 from below. The component imaging camera 18 is a 3D camera that can capture three-dimensional images of the component 50. In this example, a stereo camera such as the one shown in Figure 2 is used, which captures stereo images of the component 50 from two angles.

Figure 2 is a schematic diagram of the component imaging camera 18. As shown in Figure 2, the component imaging camera 18 includes a first illumination unit 20, a first camera main body unit 22, a second illumination unit 24, a second camera main body unit 26, and a mirror 28.

The first illumination unit 20 and the second illumination unit 24 each include multiple LEDs, a refractive lens, and a diffuser. The first illumination unit 20 is positioned to irradiate a predetermined component imaging position PI above the component imaging camera 18 with illumination light from vertically below, while the second illumination unit 24 is positioned to irradiate the component imaging position PI with illumination light from diagonally below. The position of the component 50 in the Z direction is adjusted by the head 15 so that its underside, i.e., the underside of the component body 51, passes through this component imaging position PI.

The first camera body unit 22 and the second camera body unit 26 are both line sensors with multiple CCD or CMOS elements arranged in the X direction. The first camera body unit 22 is located below the first illumination unit 20, and the second camera body unit 26 is located below the first camera body unit 22 on the opposite side of the component 50 (component imaging position PI) from the second illumination unit 24.

Light irradiated from the first illumination unit 20 onto the component imaging position PI is reflected downward by the component 50 and received by the first camera body 22 through a light-transmitting section (opening) provided in the first illumination unit 20. Light irradiated from the second illumination unit 24 onto the component imaging position PI is specularly reflected in the opposite direction by the component 50, then reflected by the mirror 28 and received by the second camera body 26. As the component 50 passes through the component imaging position PI in the Y direction, the first camera body 22 and the second camera body 26 capture full images of the component 50 at different angles. That is, the component imaging camera 18 captures an image of the component 50 taken from directly below in the vertical direction (referred to as a vertical image) and an image of the component 50 taken from diagonally below (referred to as an oblique image).

In this example, the component imaging camera 18 is provided so as to capture an image of the component 50 as the component 50 moves through the component imaging position PI in the Y direction, but the component imaging camera 18 may also be provided so as to capture an image of the component 50 as the component 50 moves in the X direction.

This component mounting device 1 executes the following component mounting process. That is, when the board P is brought into the work position, the head 15 moves back and forth between the component supply unit 12 and the board P, picking up a component 50 from the tray feeder 13 (tray 13a) and transporting it onto the board P, and mounting the component 50 in a predetermined position on the board P. At this time, the head 15 moves so that the picked component 50 passes through the component imaging position PI, and an image of the component 50 is captured by the component imaging camera 18. Based on this image, a visual inspection of the component 50 is performed and the head 15 recognizes its suction state. Any component 50 determined to be defective during the visual inspection is not mounted on the board P and is released to a predetermined disposal area.

[Configuration of the control system of the component mounting apparatus 1]
4 is a block diagram showing the control system of the component mounting apparatus 1. As already described, the component mounting apparatus 1 includes the control unit 4. The control unit 4 is configured to include a CPU, ROM, RAM, peripheral circuits, etc. The control unit 4 controls the operation of each component of the apparatus main body 2 by the CPU executing a control program stored in the ROM. The control unit 4 includes, as its main functional components, a mounting control unit 30, a transport control unit 32, an image processing unit 34, and a storage unit 36, etc.

The mounting control unit 30 comprehensively controls the component mounting process performed by the device main body 2 and executes various calculation processes associated with this control. The component mounting process also includes processes such as the visual inspection of the component 50 and recognition of the suction state of the component 50, as previously described. If the component 50 is the SOP shown in Figure 3, the visual inspection includes a flatness (coplanarity) inspection of the joint 52a of the component 50. This flatness inspection will be described in detail later.

The transport control unit 32 controls the transport operation of the substrate P by the substrate transport mechanism 10 (conveyor 11), i.e., the transport of the substrate P from outside the machine to the work position, the transport of the substrate P from the work position to outside the machine, and the holding and release of the substrate P by the clamping mechanism.

The image processing unit 34 generates a digital image of the component 50 based on the image signal output from the component imaging camera 18. More specifically, it generates a vertical image of the component 50 based on the image signal output from the first camera main body unit 22, and generates an oblique image of the component 50 based on the image signal output from the second camera main body unit 26. The mounting control unit 30 performs processes such as visual inspection of the component 50 and recognition of the pickup state based on these images.

The memory unit 36 stores various programs executed by the mounting control unit 30 and the transport control unit 32, as well as various data referenced when these programs are executed.

In this example, the component imaging camera 18 and the control unit 4 correspond to the "inspection device" of the present invention. The component imaging camera 18 and the control unit 4 also correspond to the "position detection unit" of the present invention, and the control unit 4 (mainly the mounting control unit 30) corresponds to the "determination unit" of the present invention.

[Flatness inspection process for component 50]
In the component 50, variations in the height of the bonding portions 52a may occur due to deformation of the leads 52. Large variations in the height of the bonding portions 52a can lead to poor contact between the substrate P (circuit) and the bonding portions 52a, and ultimately to the production of defective substrates. Therefore, in the component mounting apparatus 1, before mounting the component 50 on the substrate P, the control unit 4 performs an inspection of the variations in the height of the bonding portions 52a, i.e., the flatness (coplanarity) of the bonding portions 52a, as one item of the appearance inspection.

Figure 5 is a flowchart showing the control of the flatness inspection process. This flatness inspection process begins simultaneously with the completion of the picking operation of the component 50 by the head 15. When this flowchart starts, the mounting control unit 30 determines whether the component imaging camera 18 has captured an image of the component 50 (step S1). If the answer is yes, the mounting control unit 30 detects the three-dimensional coordinates of the joints 52a of each lead 52 from the captured image (step S3).

In more detail, the mounting control unit 30 first detects the XY coordinates of the joint 52a of each lead 52 based on a vertical image of the component 50. In this case, the XY coordinates are detected using the center of the joint surface (the surface that abuts against the substrate P) of the joint 52a as the detection point. If the joint surface is rectangular, for example, the position where the diagonal lines of the joint surface intersect is used as the detection point, and the XY coordinates of the detection point are detected. Hereinafter, the coordinates of the joint 52a refer to the coordinates of this detection point.

Next, the mounting control unit 30 detects the XY coordinates of the joint 52a of each lead 52 based on the oblique image of the component 50, and calculates the Z coordinate of the joint 52a of each lead 52 based on the difference between the XY coordinates of the joint 52a detected based on the vertical image and the XY coordinates of the joint 52a detected based on the oblique image. Specifically, the Z coordinate of the joint 52a of each lead 52 is calculated based on a well-known equation that is based on the amount of deviation between the XY coordinates of the joint 52a in both images and the relative angle between the first and second camera bodies 22, 26. In this way, the three-dimensional coordinates (XYZ coordinates) of the joint 52a of each lead 52 are obtained.

Next, the mounting control unit 30 calculates the reference plane 50L from the XYZ coordinates of each joint 52a acquired in step S3 (step S5). Specifically, it calculates a least-squares plane, which is a virtual plane, from the XYZ coordinates of the joint 52a of each lead 52, and sets this least-squares plane as the reference plane 50L.

Figure 7 shows a schematic diagram of each lead 52 of a component 50 and an example of a reference plane 50L (least-squares plane). In the figure, deformed leads 52 are shown as columns, and the height of the joint 52a (joint surface) when there is no deformation is set to "0." An upwardly extending column represents an upwardly deformed lead 52 (a lead 52 with lead lift), while a downwardly extending column represents a downwardly deformed lead 52 (a lead 52 with lead sinking). The tip of each column is the joint 52a (joint surface).

The mounting control unit 30 executes a process to determine whether the flatness of the joint 52a is good or bad based on this reference plane 50L (step S7). Figure 6 is a flowchart (subroutine) showing the control of the flatness determination process.

In the flatness determination process, the mounting control unit 30 first executes a first mode consisting of the following steps S11 and S13. That is, for each lead 52, the mounting control unit 30 calculates the height difference (distance in the Z direction) of the joint 52a relative to the reference plane 50L, and calculates the difference Z1 between the maximum and minimum values, as shown in FIG. 7 (step S11). In this example, the height difference is calculated as - (negative) if the joint 52a is located above the reference plane 50L, and + (positive) if the joint 52a is located below the reference plane 50L, and the difference Z1 between the maximum and minimum values of the height difference is calculated (Z1 = |maximum value - minimum value|). In other words, the height difference Z1 between the joint 52a located most negatively and the joint 52a located most positively is calculated.

Then, the flatness is determined based on the height difference Z1 calculated in step S11. Specifically, it is determined whether the height difference Z1 calculated in step S11 is less than the threshold value Zt (step S13). If the answer is No, the mounting control unit 30 determines that the flatness of the component 50 is poor (step S29) and ends the flatness determination process.

The threshold value Zt is, for example, the maximum height difference between the joints 52a of each lead 52 at which the joints 52a can come into contact with the substrate P, or a value close to that maximum height, and is set taking into account the thickness of the solder applied to the substrate P. The threshold value Zt is stored in the memory unit 36 as part of the various data.

If step S13 returns Yes, i.e., if the flatness is determined to be good in the first mode, the mounting control unit 30 further executes the second mode, which consists of the following steps S15 to S25.

In the second mode, the mounting control unit 30 calculates the height difference Z2 between positions on the reference plane 50L corresponding to two leads 52 that are spaced apart from each other and determines whether the flatness is good or bad based on this height difference Z2. In this case, the mounting control unit 30 executes the second mode for three sets of leads 52, each set consisting of two leads 52.

Specifically, first, for the leads 52 located at both ends of the first lead row L1, the mounting control unit 30 calculates the height difference Z2 between the positions on the reference plane 50L corresponding to both leads 52, based on the following formula 1:

Z2=b(X2-X1)+c(Y2-Y1)...(1)
Here, X1 and Y1 are the XY coordinates of the lead 52 located at one end of the first lead row L1, and X2 and Y2 are the XY coordinates of the lead 52 located at the other end. The reference plane 50L (least squares plane) is expressed by the plane equation aX+bY+cZ+d=0. This equation can be transformed into the equation Z=a+bX+cY for finding the height of the reference plane 50L, and the above equation 1 is based on this equation.

Then, it is determined whether the height difference Z2 calculated in step S15 (hereinafter referred to as height difference Z2a for distinction) is less than the threshold value Zt (step S17). If the determination is No, the mounting control unit 30 determines that the flatness of the component 50 is poor (step S29), and ends the flatness pass/fail determination process.

If the answer to step S17 is Yes, that is, if the flatness is determined to be good when focusing on the leads 52 at both ends of the first lead row L1, the mounting control unit 30 then calculates the height difference Z2 (hereinafter referred to as Z2b) between positions on the reference plane 50L corresponding to the leads 52 located at both ends of the second lead row L2 (step S19). In this case, the mounting control unit 30 calculates the height difference Z2b based on the above equation 1, using the XY coordinates of the lead 52 located at one end of the second lead row L2 as (X1, Y1) and the XY coordinates of the lead 52 located at the other end as (X2, Y2).

Then, it is determined whether the height difference Z2b calculated in step S19 is less than the threshold value Zt (step S21). If the result is No, the mounting control unit 30 determines that the flatness of the component 50 is poor (step S29) and ends the flatness determination process.

If the answer to step S21 is Yes, that is, if the flatness is determined to be good with respect to the leads 52 at both ends of the second lead row L2, the mounting control unit 30 further calculates the height difference Z2c between positions on the reference plane 50L corresponding to two specific leads 52 (a set of leads) in the first and second lead rows L1 and L2 that face each other across the component body 51 (step S23). For example, the mounting control unit 30 calculates the height difference Z2c between positions on the reference plane 50L corresponding to the first lead 52 in the first lead row L1 and the first lead 52 in the second lead row L2.

In this case, the mounting control unit 30 calculates the height difference Z2c based on the above formula 1, where the XY coordinates of the leads 52 in the first lead row L1 are (X1, Y1) and the XY coordinates of the leads 52 in the second lead row L2 are (X2, Y2).

Then, it is determined whether the height difference Z2c calculated in step S23 is less than the threshold value Zt (step S25). If the result is No, the mounting control unit 30 determines that the flatness of the component 50 is poor (step S29) and ends the flatness determination process.

On the other hand, if the answer to step S25 is Yes, that is, if the flatness of the two opposing leads 52 in the first lead row L1 and the second lead row L2 is determined to be good, the mounting control unit 30 ultimately determines that the flatness of the joint 52a of the component 50 is good (step S27).

When the flatness determination process (steps S11 to S29), including the first and second modes, is completed in this manner, the mounting control unit 30 terminates the flatness inspection process. If the flatness is ultimately determined to be poor in step S29, the mounting control unit 30 releases the component 50 as a defective component to a designated disposal area. In this case, the component 50 may be returned to the component supply unit 12 or transported to a repair station. The component 50 transported to the component supply unit 12 or repair station is reworked as necessary and then reused. Note that in this example, the processes of steps S15, S17, S19, and S21 each correspond to the "first determination step" of the present invention, and the processes of steps S23 and S25 correspond to the "second determination step" of the present invention.

[effect]
In the component mounting device 1, a flatness inspection process is executed under the control of the control unit 4 to inspect the flatness of the component 50. This flatness inspection process includes a step of detecting the XYZ coordinates (position) of the bonding portion 52 a for each lead 52 based on an image captured by the component imaging camera 18 (step S3/position detection step), a step of determining a least-squares plane for each bonding portion 52 a from the detected XYZ coordinate data (position data) of each bonding portion 52 a and setting this least-squares plane as the reference plane 50L (step S5/reference plane setting step), and a step of determining whether the flatness is good or bad (step S7/flatness pass/fail determination step).

The process of determining the flatness (step S7) uses a first mode (steps S11 and S13) to determine the flatness of each joint 52a based on the difference in elevation between the reference plane 50L and each joint 52a. Specifically, as shown in FIG. 7, the difference Z1 between the maximum and minimum elevation differences between the reference plane 50L and each joint 52a. The second mode (steps S15-S25) determines the flatness of two pre-defined, spaced-apart leads 52 based on the difference in elevation Z2 (Z2a, Z2b, Z2c) between positions on the reference plane 50L corresponding to both leads 52 (steps S27 and S29). Therefore, the above configuration (inspection method) enables more accurate determination of the flatness of each joint 52a in the component 50. This point will be explained in detail below.

Figure 8 is a side view showing an example of a component 50 whose flatness should be determined to be poor. Specifically, Figure 8(a) is a side view of a component 50 in which deformation has occurred in only some of the leads 52 in the first lead row L1, and Figure 8(b) is a side view of a component 50 in which the leads 52 in both lead rows L1 and L2 have been similarly deformed so that the height of the joints 52a changes linearly from one end to the other in the lead arrangement direction. Figure 8(c) is a side view of a component 50 in which all of the leads 52 in the second lead row L2 have been deformed upward by a fixed amount. Note that Figures 8(a) and (b) are side views of the long side (first lead row L1 side) of the component 50, and Figure 8(c) is a side view of the short side of the component 50.

In the case of a component 50 such as that shown in Figure 8(a), most of the leads 52 are normal, and the reference plane 50L (least-squares plane) is a plane that roughly follows the underside of the component body 51. Therefore, the difference in height between the bonded portion 52a of the deformed lead 52 and the reference plane 50L tends to be significant. According to the first mode, which determines whether the flatness is good or bad based on the difference in height between the reference plane 50L and the bonded portion 52a, it is possible to determine that the flatness of the component 50 is poor. In the example shown, the maximum value of this difference in height is hb, and the minimum value is ha. Therefore, if Z1 = (|hb - ha|) < threshold value Zt, the flatness can be determined to be poor.

However, in the case of a part 50 such as that shown in Figure 8(b), the reference plane 50L itself is tilted along the joint 52a, as shown in the figure, so there is almost no difference in height between the joint 52a and the reference plane 50L, or even if there is a difference, it is generally small. Therefore, in the first mode, which determines whether the flatness is good or bad based on the difference in height between the joint 52a and the reference plane 50L, Z1 < threshold Zt in many cases, making it difficult to determine that the flatness is poor. This is also true for a part 50 such as that shown in Figure 8(c).

However, in the case of a component 50 such as that shown in FIG. 8(b), a significant difference in height occurs at the joints 52a of the leads 52 located at both ends of the lead arrangement direction. Similarly, in the case shown in FIG. 8(c), a significant difference in height occurs at the joints 52a of two leads 52 facing each other across the component body 51. Therefore, by using the second mode, which compares the height differences Z2a and Z2b on the reference plane 50L corresponding to the leads 52 at both ends of the first and second lead rows L1 and L2 with a threshold value Zt, and also compares the height difference Z2c on the reference plane 50L corresponding to the two leads 52 facing each other across the component body 51 with a threshold value Zt, it is possible to determine that the flatness of a component 50 such as that shown in FIGS. 8(b) and (c) is defective.

As mentioned above, in the case of a component 50 such as that shown in FIG. 8(a), the reference plane 50L is likely to be a plane that roughly follows the underside of the component body 51. In this case, there is almost no difference in height Z2a, Z2b between the positions on the reference plane 50L corresponding to the leads 52 at both ends of each of the first and second lead rows L1, L2, or there is almost no difference in height Z2c between the positions on the reference plane 50L corresponding to each of the two leads 52 facing each other across the component body 51, or even if there is a difference, the value is relatively small. Therefore, Z2a, Z2b, Z2c are likely to be less than the threshold value Zt, and it is difficult to determine that the flatness of a component 50 such as that shown in FIG. 8(a) is poor using only the second mode.

In other words, the components 50 shown in Figures 8(a) to (c) and the appropriate judgment modes for them can be said to have a roughly complementary relationship, as shown in Figure 9. Therefore, the above configuration (inspection method) that uses the first mode and second mode in combination to judge the flatness of the component 50 makes it possible to more accurately judge the flatness of the joint 52a. As a result, the component mounting device 1 can more effectively prevent components with poor flatness from being mounted on the substrate P.

Furthermore, as already described, in the flatness pass/fail determination process (step S7), the first mode is executed, and the second mode is executed only if the flatness is determined to be good in the first mode (Yes in step S13). In other words, if the flatness is determined to be poor in the first mode (No in step S13), the second mode is not executed, and the flatness is ultimately determined to be poor (step S29). Therefore, the flatness pass/fail determination process can be performed efficiently while more accurately determining the flatness pass/fail.

Furthermore, in the flatness determination process (step S7), the part's flatness is ultimately determined to be good (step S27) only if the flatness is determined to be good in both the first mode and the second mode (Yes in step S25). This has the advantage of providing high reliability in the determination results for parts 50 whose flatness is determined to be good.

Furthermore, in the processes of steps S15, S19, and S25 of the second mode, the elevation differences Z2a, Z2b, and Z2c of the positions on the reference plane 50L corresponding to the two leads 52 are calculated, and these elevation differences Z2a, Z2b, and Z2c are compared with the threshold value Zt. This makes it possible to more reliably determine whether the flatness of the component 50 is defective, as shown in Figures 8(b) and (c). That is, in the processes of steps S15, S19, and S23, it is also possible to calculate the actual elevation difference (i.e., the elevation difference in the Z coordinate) of the joint 52a of the two leads 52 and compare this elevation difference with the threshold value Zt.

However, this method has the following drawbacks. For example, in the component 50 shown in Figure 8(b), if we assume that the rightmost lead 52 in the figure is not deformed, there will be almost no height difference between the leads 52 at both ends, i.e., the joints 52a of the two leads 52 that are the subject of calculation of the height difference Z2a (Z2b). Therefore, if the actual height difference at the joints 52a is calculated and compared with the threshold value Zt, it is conceivable that the flatness will be determined to be good even if all leads 52 other than the leads 52 at both ends are deformed.

In contrast, with a configuration (inspection method) that calculates the height difference Z2a (Z2b) between the positions on the reference plane 50L corresponding to the leads 52 at both ends and compares this height difference Z2a (Z2b) with the threshold value Zt, the gradient of the reference plane 50L is reflected in the height difference Z2a (Z2b), and deformation (floating) of the leads 52 other than those at both ends is effectively taken into account.

Therefore, the above configuration (inspection method) calculates the height differences Z2a, Z2b, and Z2c for two leads 52 at positions on the reference plane 50L corresponding to both leads 52, and compares these height differences Z2a, Z2b, and Z2c with the threshold value Zt. This makes it possible to more reliably determine whether the flatness of the component 50, as shown in Figures 8(b) and (c), is poor, compared to when the flatness is determined based on the actual height difference of the joint 52a.

[Modifications, etc.]
The component mounting apparatus 1 described above is an example of a preferred embodiment of the present invention, and the specific component inspection method (inspection apparatus) and the specific configuration of the component mounting apparatus 1 can be changed without departing from the gist of the present invention. For example, the following configurations (methods) can also be applied.

(1) In the embodiment, the component inspection method (inspection device) of the present invention was described using an SOP, a two-way lead package component, as an example of the component 50. However, the present invention is also applicable to the inspection of two-way lead package components other than SOPs, and four-way lead package components, such as QFPs. As shown in FIG. 10, a QFP is a component with multiple leads 52 arranged along each side of a component body 51 that is square in plan view. In other words, it is a component with first to fourth lead rows L1 to L4 around the periphery of the component body 51.

Even when the component 50 is a QFP, flatness inspection processing can be performed in accordance with the flowcharts shown in Figures 5 and 6. In this case, as a second mode of the flatness determination processing (step S7), in addition to the flatness determination processing focusing on the leads 52 at both ends of the first lead row L1 (steps S15, S17) and the flatness determination processing focusing on the leads 52 at both ends of the second lead row L2 (steps S19, S21), flatness determination processing focusing on the leads 52 at both ends of the third lead row L3 and flatness determination processing focusing on the leads 52 at both ends of the fourth lead row L4 are performed. Furthermore, in addition to the flatness determination process (steps S23 and S25) that focuses on two leads 52 of the first lead row L1 and the second lead row L2 that face each other across the component body 51, it is also possible to perform flatness determination process that focuses on two leads 52 of the third lead row L3 and the fourth lead row L4 that face each other across the component body 51.

(2) In this embodiment, in the process of determining whether the flatness of the part 50 is good (step S7), the first mode (steps S11 and S13) is first executed, and if the flatness is determined to be good in the first mode (Yes in step S13), the second mode (steps S15 to S25) is executed. However, conversely, the second mode may be executed, and if the flatness is determined to be good in the second mode, the first mode may be executed. Alternatively, both the first mode and the second mode may be executed.

(3) In this embodiment, in the processing of step S15 in the second mode, for the leads 52 located at both ends of the first lead row L1, the elevation difference Z2a between positions on the reference plane 50L corresponding to both leads 52 is calculated (step S15). Furthermore, in the processing of step S19, for the leads 52 located at both ends of the second lead row L2, the elevation difference Z2b between positions on the reference plane 50L corresponding to both leads 52 is calculated (step S19). However, the positions of the leads 52 for which the elevation differences Z2a and Z2b are calculated are not necessarily limited to the leads 52 at both ends of the lead rows L1 and L2, as long as they are two leads 52 spaced apart from each other in the lead alignment direction.

In addition, in this embodiment, in the processing of step S23 in the second mode, for two leads 52 in the first lead row L1 and the second lead row L2 that face each other across the component body 51, the height difference Z2c between the positions on the reference plane 50L corresponding to both leads 52 is calculated (step S23). However, the two leads 52 for which the height difference Z2c is calculated are not necessarily limited to leads 52 that face each other across the component body 51. As long as the leads 52 are located on opposite sides of the component body 51, the two leads 52 may be offset from each other in the lead alignment direction.

(4) In this embodiment, a least-squares plane for the joints 52a of all leads 52 of the component 50 is calculated (step S5 in FIG. 5), and this least-squares plane is used as the reference plane 50L. Then, in steps S15, S19, and S23 of the second mode of the flatness pass/fail judgment process (FIG. 6), the elevation difference Z2 (Z2a, Z2b, Z2c) of the positions on this reference plane 50L corresponding to the two leads 52 (joints 52a) is calculated. However, in steps S15 and S19, a least-squares plane (least-squares line) for the joints 52a of the leads 52 may be calculated for each lead row, separately from the reference plane 50L, and the elevation difference (Z2a, Z2b) of the positions on this least-squares plane (least-squares line) corresponding to the two leads 52 may be calculated.

Similarly, when the component 50 is a four-way lead package component (QFP) as shown in FIG. 10, the processing of step S23 in the second mode may involve calculating a least-squares plane of the joints 52a of the leads 52 for the first lead row L1 and the second lead row L2, and calculating the height difference (Z2c) between positions on this least-squares plane corresponding to the two opposing leads 52. Also, for the third lead row L3 and the fourth lead row L4, the least-squares plane of the joints 52a of the leads 52 may be calculated, and calculating the height difference (Z2c) between positions on this least-squares plane corresponding to the two opposing leads 52.

(5) In the embodiment, a stereo camera configured as shown in FIG. 2 is used as the component imaging camera 18. However, the specific configuration of the component imaging camera 18 is not limited to that of the embodiment (FIG. 2) as long as it can capture vertical and oblique images of the component 50 positioned at the component imaging position PI. Essentially, it is sufficient that the first camera 22 can receive the vertical component of the illumination light reflected by the component 50 along the optical axis, and the second camera body 22 can receive the specularly reflected component at a predetermined angle relative to the vertical along the optical axis. Therefore, the component mounting device 18 may be configured, for example, with a single illumination unit shared by the first camera body 22 and the second camera body 26. Furthermore, the mirror 28 is a means for guiding light specularly reflected by the component 50 to the second camera body positioned below the first camera body 22. Therefore, if the layout allows the first camera body 22 to be positioned so that it can directly receive light specularly reflected by the component 50, the mirror 28 can be omitted.

(6) In the embodiment, the component 50 is imaged using the component imaging camera 18, which is a stereo camera, and the three-dimensional coordinates of the joints 52a of each lead 52 of the component 50 are detected from the image. However, the component 50 may also be imaged using a 3D camera other than a stereo camera. Furthermore, the three-dimensional coordinates of the joints 52a may be detected by scanning the joints 52a of each lead 52 using a laser-based measuring device or the like.

(7) In this embodiment, all of the processes in steps S11 to S29 in FIG. 6 are considered to be part of the process for determining whether the flatness of the component 50 is good or bad. In other words, the processes in both the first mode and the second mode are considered to be part of the process for determining whether the flatness is good or bad. However, the processes in steps S11 and S13 may be considered to be part of the process for determining whether the flatness is good or bad, and the processes in steps S13 to S25 may be considered to be part of the process for determining whether the tilt of the lead 52 is good or bad. In other words, the first mode may be used to determine whether the flatness is good or bad, and the second mode may be used to determine whether the tilt of the lead 52 is good or bad.

REFERENCE SIGNS LIST 1 Component mounting device 4 Control unit 10 Conveying mechanism 13 Tray feeder 15 Head 15a Nozzle 16 Head driving mechanism 18 Component imaging camera 30 Mounting control unit 50 Component 51 Component body 51
52 Lead 52a Joint L1 First lead row L2 Second lead row P Substrate

Claims (13)

1. A method for inspecting flatness of joints of a component having a plurality of terminals, each of the terminals having a joint to be joined to a substrate, the method comprising:
a position detection step of detecting the position of the joint portion of each of the plurality of terminals;
a reference plane setting step of determining a least-squares plane of the joint from the position data detected in the position detection step and setting the least-squares plane as a reference plane;
a flatness determining process for finally determining whether the flatness is good or bad by using a first mode for determining whether the flatness is good or bad based on a difference in height between the reference plane and the joint portion of each terminal, and a second mode for determining whether the flatness is good or bad based on a difference in height between the joint portions of two predetermined terminals spaced apart from each other,
a component inspection method , characterized in that the height difference of the joint portions of the two spaced-apart terminals in the second mode is determined by the height difference of positions on the reference plane corresponding to the two terminals . 2. The component inspection method according to claim 1 , wherein in the flatness determination step, either the first mode or the second mode is executed, and only when the flatness is determined to be good in the first mode, the other mode is executed. 3. The component inspection method according to claim 1 , further comprising:
the component is a package component having a component body that is rectangular in plan view, and the plurality of terminals are arranged along opposing side surfaces of the component body,
The second mode includes a first determination step of determining whether the flatness is good or bad based on the difference in height between the joints of two of the plurality of terminals that are spaced apart from each other in the terminal arrangement direction. 3. The component inspection method according to claim 1 , further comprising:
the component is a package component having a component body that is rectangular in plan view, and the plurality of terminals are arranged along opposing side surfaces of the component body,
The component inspection method is characterized in that the second mode includes a second judgment step of judging whether the flatness is good or bad based on the difference in height between the joints of the two terminals arranged on opposite sides of the component body. 5. The component inspection method according to claim 1 , further comprising:
A component inspection method characterized in that, in the flatness determination process, the flatness is finally determined to be good only if the flatness is determined to be good in both the first mode and the second mode. 1. A method for inspecting flatness of joints of a component having a plurality of terminals, each of the terminals having a joint to be joined to a substrate, the method comprising:
a position detection step of detecting the position of the joint portion of each of the plurality of terminals;
a reference plane setting step of determining a least-squares plane of the joint from the position data detected in the position detection step and setting the least-squares plane as a reference plane;
a flatness determining process for finally determining whether the flatness is good or bad by using a first mode for determining whether the flatness is good or bad based on a difference in height between the reference plane and the joint portion of each terminal, and a second mode for determining whether the flatness is good or bad based on a difference in height between the joint portions of two predetermined terminals spaced apart from each other,
the component is a package component having a component body that is rectangular in plan view, and the plurality of terminals are arranged along opposing side surfaces of the component body,
The second mode is a component inspection method characterized in that it includes a judgment step of judging whether the flatness is good or bad based on the difference in height of the joint portions of the two terminals arranged on opposite sides of the component body. 1. An inspection apparatus for inspecting flatness of a component having a plurality of terminals, each of the terminals having a bonding portion to be bonded to a substrate, comprising:
a position detection unit that detects the position of the joint portion of each of the plurality of terminals;
a determination unit that determines whether the flatness is good or bad based on the position data detected by the position detection unit,
The determination unit
a reference plane setting process for determining a least-squares plane of the joint based on the position data and setting the least-squares plane as a reference plane;
a flatness determination process for finally determining whether the flatness is good or bad by using a first mode in which the flatness is determined based on a difference in height between the reference plane and the joint portion of each terminal, and a second mode in which the flatness is determined based on a difference in height between the joint portions of two predetermined terminals spaced apart from each other ;
a component inspection device characterized in that the height difference of the joint portions of the two spaced-apart terminals in the second mode is the height difference of positions on the reference plane corresponding to the two terminals, respectively . 8. The part inspection device according to claim 7 , wherein the determination unit executes either the first mode or the second mode in the flatness determination process, and executes the other mode only when the flatness is determined to be good in the one mode. 9. The component inspection device according to claim 7 or 8 ,
the component is a package component having a component body that is rectangular in plan view, and the plurality of terminals are arranged along opposing side surfaces of the component body,
The second mode includes a first determination step of determining whether the flatness is good or bad based on the difference in height between the joints of two of the plurality of terminals that are spaced apart in the terminal arrangement direction. 9. The component inspection device according to claim 7 or 8 ,
the component is a package component having a component body that is rectangular in plan view, and the plurality of terminals are arranged along opposing side surfaces of the component body,
The second mode of the component inspection device is characterized in that it includes a second judgment step of judging whether the flatness is good or bad based on the difference in height between the joints of the two terminals arranged on opposite sides of the component body. 11. The component inspection device according to claim 7 ,
A part inspection device characterized in that, in the flatness determination process, the determination unit finally determines that the flatness is good only if the flatness is determined to be good in both the first mode and the second mode. 1. An inspection apparatus for inspecting flatness of a component having a plurality of terminals, each of the terminals having a bonding portion to be bonded to a substrate, comprising:
a position detection unit that detects the position of the joint portion of each of the plurality of terminals;
a determination unit that determines whether the flatness is good or bad based on the position data detected by the position detection unit,
The determination unit
a reference plane setting process for determining a least-squares plane of the joint based on the position data and setting the least-squares plane as a reference plane;
a flatness determination process for finally determining whether the flatness is good or bad by using a first mode in which the flatness is determined based on a difference in height between the reference plane and the joint portion of each terminal, and a second mode in which the flatness is determined based on a difference in height between the joint portions of two predetermined terminals spaced apart from each other;
the component is a package component having a component body that is rectangular in plan view, and the plurality of terminals are arranged along opposing side surfaces of the component body,
The second mode of the component inspection device includes a determination step for determining whether the flatness is good or bad based on the difference in height between the joints of the two terminals arranged on opposite sides of the component body. A component mounting apparatus that uses a movable head to pick up components from a component supply unit, transport them onto a substrate, and mount the components on the substrate,
the component is a component including a plurality of terminals each having a joining portion to be joined to a substrate,
The component mounting apparatus is characterized in that it is equipped with the inspection device described in any one of claims 7 to 12 as a device for inspecting the flatness of the joint of the component taken out by the head from the component supply unit.