JP2013069872A - Substrate inspection device, component mounting system, substrate inspection method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate inspection device capable of detecting poor soldering accurately for a plurality of failure causes.SOLUTION: After solder printing process, solder volume, solder shape, and solder print position are measured. After component mounting process, component shape and component mounting position are measured. A substrate inspection device determines the contact area of a determination target component by utilizing solder shape, solder print position, component shape and component mounting position, and calculates an evaluation value corresponding to the ratio of multiplication value of the contact area and the solder volume. The substrate inspection device determines whether or not there is a failure due to floating of a component for the determination target component, by comparing the evaluation value with a threshold.

Description

  The present invention relates to a board inspection apparatus, a board inspection method, and a program for inspecting a soldering failure of a board. The present invention also relates to a component mounting system including a board inspection apparatus.

  SMT (Surface Mount Technology) is known as a component mounting technology for a substrate. SMT is a technique in which components are mounted so as to be placed on a substrate, and components are fixed and connected by soldering to the mounting surface, instead of forming component mounting holes in the substrate. The component mounting on the substrate by this SMT is performed in the order of a solder printing process, a component mounting process, and a reflow process.

  As components mounted by this SMT, chip-type components having electrodes at both ends are widely known. This chip-type component may have a soldering defect called “component floating” or “component standing (Manhattan or tombstone)” after the reflow process. This component lifting is a phenomenon in which one end of a chip-type component is lifted (rises) from the substrate, resulting in poor solder / electrode bonding.

  As a technique for inspecting defects due to the above-described component floating, the technique of Patent Document 1 below is known. In other words, the board is imaged in each of the solder printing process, the component mounting process, and the reflow process, the floating defect is inspected from the captured image of the reflow process, and when the floating defect is detected, the solder is detected from the captured image of the component mounting process. The presence / absence of bleeding is determined, and when there is solder bleeding, it is determined that the cause of the floating failure is an excessive amount of solder paste. When there is no solder blur, if the difference in the solder area at both ends of the component is greater than or equal to the threshold value, it is determined that the amount of solder paste is excessive.

Japanese Patent No. 4617998

  According to the technique described in Patent Document 1, it is possible to detect a defect due to an excessive amount of solder paste based on the presence or absence of solder bleeding. Further, it is possible to detect a defect caused by an excessive amount of solder paste based on a difference in solder area between both ends of the component. However, these defects are detected independently of each other.

  In practice, a defect may occur only when a plurality of causes are combined. Also, as a result of these multiple causes canceling each other's actions, no defect may occur. In the configuration in which a plurality of causes are individually analyzed as in Patent Document 1, it is impossible to accurately detect the presence or absence of a defect due to the combination of a plurality of causes as described above.

  Therefore, an object of the present invention is to provide a board inspection apparatus capable of accurately detecting a soldering defect in response to a plurality of causes of defects.

  The present invention has been made to solve the above-described problems, and the substrate inspection apparatus according to one aspect of the present invention is configured to measure the solder volume as a measurement result for the solder applied to the pads of the substrate by the solder printing process. A solder information acquisition unit that acquires solder information including, a component information acquisition unit that acquires component information including measurement results for components mounted on the substrate by a component mounting step after the solder printing step, Based on the solder information and the component information, the contact area between the determination target component and the pad is calculated, and based on the calculated contact area and the solder volume, the determination target soldering failure An evaluation value calculation unit for obtaining an evaluation value used for determining the presence / absence, and determining the presence / absence of a soldering defect for each of the determination target components based on the evaluation value And a good determination unit.

  Further, the component mounting system as one aspect of the present invention performs a measurement on a solder printing apparatus that performs a solder printing process of applying solder to a pad of a board, and solder applied by the solder printing apparatus, and the measurement As a result, a solder measuring device that generates solder information including a solder volume, a component mounting device that performs a component mounting process for mounting a component on the substrate coated with solder by the solder printing device, and a component mounting device that is mounted by the component mounting device By measuring the component and generating component information including the measurement result, and heating the substrate on which the component is mounted by the component mounting device to melt the solder, A reflow furnace for performing a reflow process for soldering the mounted component to the pad; and soldering in the substrate A board inspection apparatus for inspecting good, the board inspection apparatus, a solder information acquisition unit for acquiring the solder information from the solder measurement device, and a component information acquisition unit for acquiring the component information from the component mounting device; The contact area between the determination target component and the pad is calculated based on the solder information and the component information, and the soldering of the determination target component is calculated based on the calculated contact area and the solder volume. An evaluation value calculation unit for obtaining an evaluation value used for determining the presence / absence of a defect and a defect determination unit for determining the presence / absence of a soldering defect for each component to be determined based on the evaluation value.

  Further, the substrate inspection method as one aspect of the present invention includes a solder information acquisition step of acquiring solder information including a solder volume as a measurement result for solder applied to a pad of a substrate by a solder printing process, and the solder Based on the component information acquisition step for acquiring the component information including the measurement result for the component mounted on the substrate by the component mounting process after the printing process, and the determination target based on the solder information and the component information An evaluation value for calculating an evaluation value used for calculating the contact area between the component and the pad, and determining whether there is a soldering defect in the determination target component based on the calculated contact area and the solder volume A calculation step; and a failure determination step of determining whether there is a soldering failure for each of the determination target components based on the evaluation value. .

  In addition, the program as one aspect of the present invention includes a solder information acquisition unit configured to acquire solder information including a solder volume as a measurement result for a solder applied to a pad of a substrate by a solder printing process, the solder Component information acquisition means for acquiring component information including measurement results for components mounted on the substrate in a component mounting process after the printing process, based on the solder information and the component information And a pad contact area, and based on the calculated contact area and the solder volume, an evaluation value calculation for obtaining an evaluation value used to determine whether there is a soldering defect in the determination target component Means for functioning as a defect determination means for determining the presence or absence of a soldering defect for each of the determination target components based on the evaluation value

  According to the present invention, there is obtained an effect that it is possible to provide a board inspection apparatus capable of accurately detecting a soldering defect in response to a plurality of causes of defects.

It is a figure which shows the structural example of the component mounting system containing the board | substrate inspection apparatus as embodiment of this invention. It is a figure which shows the board | substrate with which the solder was printed by the solder printing process. It is a figure which shows the board | substrate with which components were mounted | worn by the component mounting process. It is a figure which shows typically the surface tension according to the solder volume which arises in the state which the solder has melted by the reflow process. It is a figure which shows typically the surface tension according to the contact area of a pad and components produced in the state which the solder has melted by the reflow process. It is a figure which shows the structural example of the board | substrate inspection apparatus in this embodiment. It is a figure which shows the function structural example of the board | substrate inspection apparatus in this embodiment. It is a figure which shows the structural example of solder information. It is a figure which shows the structural example of component information. It is a figure which shows the structural example of the evaluation value calculation part in this embodiment. It is a figure which shows one state example of the contact area of the pad with respect to the component after a component mounting process, and a solder volume. It is a figure which shows one state example of the contact area of the pad with respect to the component after a component mounting process, and a solder volume. It is a figure which shows one state example of the contact area of the pad with respect to the component after a component mounting process, and a solder volume. It is a flowchart which shows the process sequence of the component mounting system of this embodiment. It is a flowchart which shows the example of a process sequence which the board | substrate inspection apparatus of this embodiment performs.

[Component mounting system configuration]
FIG. 1 shows a configuration example of a component mounting system 1 including a board inspection apparatus 100 of the present embodiment. The component mounting system 1 of the present embodiment performs component mounting by soldering a component to an appropriate position on a board, and includes a plurality of devices for that purpose. Moreover, the component mounting system 1 of this embodiment corresponds to SMT (Surface Mount Technology). In SMT, components are mounted on a board and soldered to the component mounting surface on the board to fix and connect the components. In this order, the solder printing process, the component mounting process, and the reflow process are performed. Proceed with

  The solder printing process is a process of applying cream-like solder to the electrodes 31 called pads formed on the substrate. The component mounting step is a step of mounting so that the component is placed on the pad position where the cream-like solder is applied as described above. The reflow process is a process of melting the solder by heating the entire substrate on which the component is mounted, thereby fixing the component to the substrate.

  The component mounting system 1 of this embodiment includes a solder printing device 2, a solder measuring device 3, a component mounting device 4, a component measuring device 5, a reflow furnace 6, and a board inspection device 100.

  The solder printing apparatus 2 is an apparatus that executes an operation as a solder printing process. The solder printing apparatus 2 carries in the board 10 on which a pad pattern, which is a conductor to which components are fixed, is formed. The solder printing apparatus 2 applies cream-like solder to the pad of the board 10 that is carried in. This solder application is also referred to as screen printing, for example.

  The board 10 discharged from the solder printing apparatus 2 after the solder application is completed is conveyed to the solder measuring apparatus 3. The solder measuring device 3 performs measurement on the solder applied by the solder printing device 2 for each substrate 10 conveyed, and generates solder information including the solder volume indicating the solder volume as the measurement result. Specifically, the solder measuring device 3 measures the solder outer shape and the solder printing position in addition to the solder volume. The solder outer shape indicates, for example, a size (corresponding to an area) and a thickness (height) in the planar direction of the applied solder. The solder printing position indicates a position where the solder is printed as a position where the solder is printed, for example, a predetermined position on the substrate 10 as a reference coordinate.

  As described above, the solder is applied by the solder printing device 2 and the board 10 that has been measured by the solder measuring device 3 is carried into the component mounting device 4. The component mounting apparatus 4 performs a component mounting process for mounting components such that the electrodes are positioned with respect to the pads of the substrate 10.

  The board 10 discharged from the component mounting device 4 after the component mounting is completed is conveyed to the component measuring device 5. The component measuring device 5 performs measurement on the component mounted by the component mounting device 4 for each substrate 10 conveyed, and generates component information including the measurement result. Specifically, the component measuring apparatus 5 measures the component outer shape and the component mounting position. The component outer shape includes, for example, the size of the mounted component in the planar direction. The solder printing position indicates coordinates at which a component is mounted as a position at which the component is mounted, for example, using a predetermined position on the substrate 10 as a reference coordinate.

  In the reflow furnace 6, the component 10 is mounted by the component mounting device 4 as described above, and the substrate 10 that has been measured by the component measuring device 5 is carried in. The reflow furnace 6 performs a reflow process in which the mounted component is soldered to the pad by heating the loaded substrate 10 to melt the solder. Thereby, the board | substrate 10 mounted in the state in which components were fixed is discharged | emitted from the reflow furnace 6. FIG.

  The board inspection apparatus 100 inspects soldering defects on the board 10. That is, it is determined whether or not there is a soldering failure by the board inspection apparatus 100. A configuration for the substrate inspection apparatus 100 to determine whether there is a soldering defect will be described later.

[Examples of substrate states according to solder printing process and component mounting process]
FIG. 2A and FIG. 2B are a plan view and a side view showing a state example of the substrate 10 on which solder is applied by the solder printing apparatus 2 (solder printing process).

  In the figure, a pair of pads 11a and 11b corresponding to one and the same component among the pads formed on the substrate 10 are extracted and shown. Components corresponding to the pads 11a and 11b are also called chip components, have a chip-shaped outer shape, and electrodes to be joined to each of the pads 11a and 11b by soldering are provided at both ends thereof. By screen printing performed by the solder printing apparatus 2, creamy solders 21a and 21b are applied onto the pads 11a and 11b as shown in the figure.

  Further, the plan view of FIG. 3A and the side view of FIG. 3B are formed on the substrate 10 shown in FIGS. 2A and 2B by the component mounting apparatus 4 (component mounting step). On the other hand, the state where the component 30 is mounted is shown. As shown in this figure, the component 30 as the chip component is mounted such that the electrodes 31a and 31b at both ends thereof are placed on the pads 11a and 11b, respectively. Thereby, the component 30 will be in the state by which the electrodes 31a and 31b of the both ends are pressed on the solder 21a and 21b, respectively.

[Consideration of cause of soldering failure]
The chip component may have a soldering failure called “component floating” after the reflow process. This component lifting is a phenomenon in which one end of a chip-type component is lifted (rises) from the substrate, resulting in poor solder / electrode bonding. Such a defect is also referred to as “part standing (Manhattan or tombstone)”.

  Therefore, the cause of the occurrence of the component floating will be considered with reference to FIGS. In FIG. 4A, the vicinity of one electrode 31a of both ends of the component 30 is enlarged, and the solder 21a applied to the pad 11a is melted by heating of the reflow furnace 6 as a reflow process. Is shown.

  The pad 11a, the solder 21, and the electrode 31 shown in this figure correspond to any one of the set of the electrode 31a, the solder 21a, and the pad 11a and the set of the pad 11b, the solder 21b, and the electrode 31b in FIG. Hereinafter, when it is not necessary to distinguish between the pads 11a and 11b, the solder 21a and the solder 21b, and the electrode 31a and the electrode 31b, they are referred to as the pad 11, the solder 21, and the electrode 31 as shown in FIG. .

  The surface tension F generated when the solder 21 is melted acts in the tangential direction of the surface of the solder 21 with respect to the interface between the electrode 31 and the solder 21 as shown in the figure. The horizontal component Fh of the surface tension F is a force acting in the horizontal direction with respect to the upper end portion of the electrode 31 and is represented by the product of the sine of the contact angle θ and the surface tension F. Since the horizontal component Fh acts as a torque centered on the lower corner of the electrode 31 indicated as point C, it is considered that the horizontal component Fh has a large relationship with the factors that cause component floating. In other words, for each horizontal component Fh of the solders 21a and 21b, the larger one is relative to the other, the stronger the force that pulls the component 30 by that one, and the higher the possibility that component floating will occur. .

  Therefore, the horizontal component Fh in a typical state example of some solders 21 will be considered. First, FIG.4 (b) shows the case where the application quantity of the solder 21 by a solder printing process is smaller than the case of Fig.4 (a). Thus, when the application amount of the solder 21 is small, the solder 21 is thinly spread from the electrode 31 to the pad 11, so that the contact angle θ is smaller than in the case of FIG. Here, assuming that there is no large variation in the components of the solder 21, the exit surface tension F is the same in the cases of FIG. 4A and FIG. Thereby, the horizontal direction component Fh of FIG.4 (b) becomes smaller than the case of Fig.4 (a).

  On the other hand, FIG.4 (c) shows the case where the application quantity of the solder 21 by a solder printing process is larger than the case of Fig.4 (a). In this case, since the solder 21 is raised, the contact angle θ is larger than that in the case of FIG. Also in this case, the exit surface tension F is the same in the case of FIG. 4A and FIG. Thereby, the horizontal direction component Fh of FIG.4 (c) becomes larger than the case of Fig.4 (a).

  As described above, the horizontal component Fh of the surface tension F varies depending on the amount of the applied solder 21, that is, the volume of the solder 21.

  Next, the horizontal component Fh of the surface tension F corresponding to the position of the electrode 31 with respect to the pad 11 will be considered with reference to FIG. FIG. 5A shows a position state in which a part of the lower surface of the electrode 31 is displaced with respect to the upper surface of the pad 11. On the other hand, FIG. 5B shows a state where the entire area of the lower surface of the electrode 31 is located with respect to the upper surface of the pad 11.

  Here, if the widths of the contact surfaces of the pad 11 and the component 30 in FIGS. 5A and 5B are expressed as W1 and W2, respectively, the relationship of (W1 <W2) is established. Although this relationship is not shown in the plan view, the contact area between the pad 11 and the component 30 is larger in FIG. 5B than in FIG. 5A.

  In the case of FIG. 5A, as the contact area between the pad 11 and the component 30 decreases, the area of the surface portion where the pad 11 does not contact the component 30 increases, and the solder 21 spreads thinly on this surface portion. become. On the other hand, in the case of FIG. 5B, as the contact area between the pad 11 and the component 30 increases, the area of the surface portion where the pad 11 does not contact the component 30 decreases, so that the solder 21 rises. Become. As a result, the contact angle θ is larger in FIG. 5B than in FIG. Accordingly, the horizontal component Fh of the surface tension F is also larger in FIG. 5B than in FIG.

  As described above, the horizontal component Fh of the surface tension F varies depending on the contact area between the pad 11 and the component 30.

  According to FIG. 4 and FIG. 5, the cause of the component floating is the difference in the horizontal component Fh between the solders 21a and 21b at both ends of the component 30. In addition, it can be seen that the magnitude of the horizontal component Fh changes according to the solder volume and the contact area of the component 30 with the pad 11. This means that there are two causes of the occurrence of component floating: a difference in solder volume at both ends of the component 30 and a difference in contact area.

  In actual occurrence of the component floating, only one of the solder volume and the contact area may be the cause. Further, although component floating does not occur directly depending on individual factors of the solder volume and contact area, component floating may occur only when they are combined. Conversely, if attention is paid to the individual factors of the solder volume and the contact area, it can be determined as a failure, but there may be cases where no failure actually occurs by canceling out the respective factors. Thus, it is necessary to determine the defect due to the component floating in consideration of the relationship between the solder volume and the contact area.

[Configuration of board inspection equipment]
The board inspection apparatus 100 according to the present embodiment is configured so as to be able to accurately perform defect determination regarding component floating in consideration of the relationship between the solder volume and the contact area. Below, the structure of the board | substrate inspection apparatus 100 is demonstrated.

  FIG. 6 shows a configuration example of the substrate inspection apparatus 100. A substrate inspection apparatus 100 shown in this figure includes a CPU 101, a RAM 102, a storage unit 103, an input interface 104, an output interface 105, and a data interface 106. These parts are connected by a data bus 107.

  The CPU 101 is a part that realizes an operation as the board inspection apparatus 100 by executing a program stored in the storage unit 103.

  The RAM 102 functions as a main storage device, and a program to be executed by the CPU 101 is read from the storage unit 103 and expanded. The RAM 102 is used as a work area when the CPU 101 executes arithmetic processing.

  The storage unit 103 functions as an auxiliary storage device, and stores programs executed by the CPU 101 and various data. As the storage unit 103, for example, a semiconductor storage device such as a hard disk or a flash memory can be employed.

  The input interface 104 collectively indicates input devices such as operation devices such as a keyboard and a mouse. The output interface 105 collectively represents output devices such as a display device (display unit) and a speaker (audio output unit).

  The data interface 106 performs communication in accordance with one or more predetermined data interface standards under the control of the CPU 101. In the present embodiment, the solder measuring device 3 and the component measuring device 5 are connected to the data interface 106. Thereby, the board inspection apparatus 100 can input the solder information generated by the solder measurement apparatus 3 and the component information generated by the component measurement apparatus 5 via the data interface 106. The configuration shown in FIG. 6 can be realized by a computer device, for example.

[Example of functional configuration of board inspection equipment]
FIG. 7 shows a configuration example of a functional unit realized by the CPU 101 of the board inspection apparatus 100 executing a program. The CPU 101 includes functional units as a solder information acquisition unit 111, a component information acquisition unit 112, an evaluation value calculation unit 113, a defect determination unit 114, and a notification control unit 115 as illustrated. Also, in the figure, among the data stored in the RAM 102, solder information 210 and component information 220 are shown as data used by the CPU 101 for board inspection.

  The solder information acquisition unit 111 acquires the solder information 210 output from the solder measuring device 3. That is, the solder information acquisition unit 111 stores the solder information 210 input via the data interface 106 in the RAM 102.

  The component information acquisition unit 112 acquires the component information 220 output from the component measuring apparatus 5. That is, the component information acquisition unit 112 stores the component information 220 input via the data interface 106 in the RAM 102. A structural example of the solder information 210 and the component information 220 will be described later.

  The evaluation value calculation unit 113 obtains an evaluation value used to determine whether or not there is a soldering defect in the component. For this reason, the evaluation value calculation unit 113 performs, for each pad 11 to which the determination target component is bonded, based on the solder information 210 and the component information 220 associated with each pad to which the determination target component is bonded. Then, the contact area with the component 30 is calculated. Then, the evaluation value is obtained based on the calculated contact area and the solder volume included in the solder information 210.

  The defect determination unit 114 determines whether or not there is a soldering defect for each determination target component based on the evaluation value. Specifically, the defect determination unit 114 determines whether or not there is a defect based on the result of comparing the evaluation value with a threshold value. Determine. In addition, the defect determination unit 114 determines that there is no defect in the substrate 10 when it is determined that there is no defect in the soldering of all the components 30 on the substrate 10.

  The notification control unit 115 executes control for notifying the operator of the occurrence of a substrate defect when the defect determination unit 114 determines that the substrate 10 is defective. As a specific example of the notification, it is conceivable that the notification control unit 115 outputs an alarm sound for notifying that a substrate defect has occurred from a speaker or the like in the output interface 105. In addition, it is conceivable to display information indicating the substrate 10 in which a defect has occurred, information indicating a location where a defect has occurred in the substrate 10, or the like on a display device in the output interface 105.

[Composition of solder information and component information]
FIG. 8 shows an example of the structure of the solder information 210. This solder information 210 reflects the result of the solder measuring device 3 measuring one substrate 10. As illustrated, the solder information 210 has a structure in which a component identifier area 211, a pad information area 212, a solder volume area 213, a solder outline area 214, and a solder printing position area 215 are associated with each other.

  The component identifier area 211 stores a component identifier for each component 30 mounted on the corresponding board 10.

  The pad information area 212 stores predetermined pad information for each of the pads 11a and 11b to which the component 30 identified by one component identifier area 211 is bonded. Specific examples of the pad information include the positions (coordinates) of the pads 11a and 11b, pad identifiers, and the like.

  The solder volume area 213 stores a value indicating the solder volume measured by the solder measuring device 3 for the solder 21 applied to the corresponding pad 11 in the pad information stored in the corresponding pad information area 212.

  The solder outline area 214 is a value indicating the outline (area and height) measured by the solder measuring device 3 for the solder 21 applied to the corresponding pad 11 with the pad information stored in the corresponding pad information area 212. Store.

  The solder printing position area 215 stores the position (coordinates) measured by the solder measuring device 3 with respect to the solder 21 applied to the corresponding pad 11 with the pad information stored in the corresponding pad information area 212.

  FIG. 9 shows a structural example of the component information 220. This component information 220 reflects the result of the component measuring apparatus 5 measuring one substrate 10. The component information 220 has a structure in which a component identifier region 221, a pad information region 222, a component outer shape region 223, and a component mounting position region 224 are associated with each other as illustrated.

  The component identifier region 221 and the pad information region 222 are the same as the component identifier region 211 and the pad information region 212 in FIG.

  The part outline area 223 stores a value indicating the outline measured by the part measuring apparatus 5 for the part 30 specified by the part identifier stored in the corresponding part identifier area 221.

  The component mounting position area 224 stores the position (coordinates) measured by the component measuring apparatus 5 with respect to the component 30 specified by the component identifier stored in the corresponding component identifier area 221.

[Configuration of Evaluation Value Calculation Unit]
With reference to FIG. 10, a configuration example of the evaluation value calculation unit 113 shown in FIG. 7 will be described. The evaluation value calculation unit 113 shown in this figure includes a contact area calculation unit 121, a multiplication unit 122, and an evaluation value calculation unit 123.

  The contact area calculation unit 121 calculates the contact area for each of the determination target component 30 and the pads 11a and 11b based on the solder information 210 and the component information 220. Specifically, when one determination target component 30 is selected, the contact area calculation unit 121 reads the solder outlines and solder printing positions of the pads 11 a and 11 b corresponding to the determination target component 30 from the solder information 210. That is, the contact area calculation unit 121 searches the solder information area 214 and the solder printing position area 215 associated with the component identifier area 211 storing the part identifier of the part 30 to be determined from the solder information 210, and stores them therein. Read the solder outline and solder printing position.

  Further, the contact area calculation unit 121 reads the component outer shape and the component mounting position of the pads 11a and 11b corresponding to the determination target component 30 from the component information 220. That is, the contact area calculation unit 121 searches the part information 220 for the part outline area 223 and the part mounting position area 224 associated with the part identifier area 221 that stores the part identifier of the part 30 to be determined, and stores it therein. Reads the component outline and component mounting position.

  With the above reading, the contact area calculation unit 121 has acquired the solder outlines and solder printing positions of the solders 21a and 21b applied to the pads 11a and 11b corresponding to the component 30 to be determined. In addition, the contact area calculation unit 121 has acquired the outer shape and the component mounting position of the component 30 to be determined.

  Accordingly, the contact area calculation unit 121 obtains an overlapping portion of the area indicated by the solder outline at each end of the part 30 and the area of the part indicated by the part outline based on the solder printing position and the component mounting position. The overlapping portion thus obtained is the contact area. Here, the contact areas obtained corresponding to the pads 11a and 11b are respectively represented as contact areas Sa and Sb.

The multiplication unit 122 multiplies the solder volume Va read from the solder information 210 corresponding to the pad 11a by the contact area Sa. Further, the solder volume Vb read from the solder information 210 corresponding to the pad 11b is multiplied by the contact area Sb. That is, the multiplication values SVa and SVb corresponding to the pads 11a and 11b are calculated by the following equations.
SVa = Sa · Va
SVb = Sb · Vb

The evaluation value calculation unit 113 calculates the evaluation value E using the multiplication values SVa and SVb. Specifically, the evaluation value E is calculated by the following formula.
E = | (SVa / SVb) −1 |
The evaluation value E obtained as described above is “0” if the multiplication values SVa and SVb are equal, and increases as the difference between the two increases. This means that the higher the evaluation value E, the higher the possibility of component floating. The evaluation value E is obtained from the multiplication values SVa and SVb. The multiplication values SVa and SVb are the product of the solder volume Va and the contact area Sa, and the product of the solder volume Vb and the contact area Sb, respectively. That is, as described above with reference to FIGS. 4 and 5, both the solder volume and the contact area that cause the component floating are included.

[Defect determination processing example of defect determination unit]
The defect determination unit 114 executes the defect determination process for each determination target component based on the evaluation value E obtained as described above. That is, the defect determination unit 114 compares the evaluation value E with a preset threshold value th, and E ≦ th
Whether or not is satisfied is determined. The defect determination unit 114 determines that the component 30 to be determined is considered to have no component floating when the above expression is satisfied, and determines that there is no defect. On the other hand, if the evaluation value E exceeds the threshold value th and the above equation is not satisfied, it is determined that there is a possibility that the solder float is likely to occur in the subsequent reflow process, and it is determined that there is a defect.

  A specific example of the defect determination will be described with reference to FIGS. FIG. 11 shows the substrate 10 after the component mounting process. In this case, as shown in the plan view of FIG. 11A, the areas of the solder 21a and the solder 21b viewed from the plane direction are the same. On the other hand, as shown in the side view of FIG. 11B, the thickness (height) of the solder 21a is larger than that of the solder 21b. This indicates that the solder 21a is larger than the solder 21b in terms of the solder volume. Here, the solder volume ratio is assumed to be “1.5” when the solder 21 b is “1”.

  Further, in the component 30 of this figure, the electrodes 31a and 31b are equally positioned with respect to the pad 11a and the pad 11b, respectively. Therefore, the contact area Sa between the component 30 and the pad 11a and the contact area Sb between the component 30 and the pad 11b are equal to (1: 1).

  That is, the state shown in FIG. 11 shows the case where the solder volume differs between the pad 11a side and the 11b side, but the contact area is the same between the pad 11a side and the 11b side. In this case, the evaluation value E is “0.5”.

  Next, the state of the substrate 10 after the component mounting process shown in FIG. 12 will be described. In the case of FIG. 12, as for the solder volume, the solder 21a is larger than the solder 21b as in the case of FIG. Also here, the solder volume ratio is assumed to be “1” for the solder 21b and “1.5” for the solder 21a.

  In addition, in the case of FIG. 12, the component 30 is mounted on the pad 11a side more than the case of FIG. Accordingly, a difference is generated such that the contact area with the component 30 on the pad 11b side is larger than that on the pad 11a side. Here, the ratio of the contact areas Sa and Sb on the pad 11a side and the pad 11b side is “5: 3”.

  As described above, FIG. 12 shows a state where there is a difference between the pad 11a side and the pad 11b side in both the solder volume and the contact area. In addition, in this case, both the solder volume and the contact area are large on the pad 11a side. Therefore, as the horizontal component Fh of the surface tension F, the pad 11a side is considerably larger than the pad 11b side.

  Next, the state of the substrate 10 after the component mounting step shown in FIG. 13 is described. As for the solder volume, the solder 21a is larger than the solder 21b in the same manner as in FIGS. Also here, the solder volume ratio is assumed to be “1” for the solder 21b and “1.5” for the solder 21a.

  Further, in the case of FIG. 13, the component 30 is mounted biased toward the pad 11 b side. Accordingly, a difference is generated such that the contact area Sb on the pad 11b side is larger than the contact area Sa on the pad 11a side. Here, the ratio of the contact areas Sa and Sb is “3: 5”.

  As described above, in FIG. 13, there is a difference between the pad 11a side and the pad 11b side in both the solder volume and the contact area. However, while the solder volume is large on the pad 11a side, the contact area is large on the pad 11b side, and the horizontal component Fh of the surface tension F that increases due to each factor is opposite to each other. And cancel each other.

  According to the equation for obtaining the previous evaluation value E, the evaluation value E obtained in the state shown in FIG. 11 is “0.5”. The evaluation value E obtained in the state shown in FIG. 12 is “1.5”. The evaluation value E obtained in the state shown in FIG. 13 is “0.1”.

  Here, for example, according to tests and simulations, the state shown in FIG. 11 is less likely to cause a floating failure, the state shown in FIG. 12 is more likely to cause a floating failure, and the state shown in FIG. It is assumed that the result that the possibility of occurrence is low is obtained. In consideration of such a result, for example, “1” can be set for the threshold th. By using the threshold value “th” of “1”, the failure determination unit 114 determines that the state illustrated in FIG. 11 is not defective, determines that the state illustrated in FIG. 12 is defective, and determines the state illustrated in FIG. Judge that there is no.

  Further, if the degree of unbalance of the solder volume or the contact area is high, component floating may occur due to any one of the factors. As a specific example, it is assumed that the state shown in FIGS. 11 and 12 is likely to cause a floating failure and the state shown in FIG. 13 is a result of a test that the possibility that a floating failure is low is obtained. To do. Corresponding to this, for example, “0.4” can be set for the threshold th. Thereby, the defect determination unit 114 can determine that the state illustrated in FIGS. 11 and 12 is defective and can determine that the state illustrated in FIG. 13 is not defective. As described above, in the present embodiment, it is possible to accurately determine the defect in consideration of the cause of the defect in both the solder volume and the contact area.

  As can be seen from the above description, the evaluation value E of the present embodiment is based on multiplication values SVa and SVb, which are products of the solder volume and the contact area of the component 30 with the pad 11. That is, as described above with reference to FIGS. 4 and 5, both the solder volume and the contact area that cause the component floating are included. Therefore, the defect determination for each determination target component 30 by the defect determination unit 114 is performed in consideration of both the solder volume and the contact area. Thereby, in this embodiment, although it is not regarded as a defect depending on individual elements of the solder volume and the contact area, even if a component float occurs due to the combination of both, it is accurately a defect. Can be determined.

  As described above, the defect determination unit 114 determines the possibility of component floating based on the evaluation value E for each component to be determined, that is, performs defect determination. And based on the result of having performed the defect determination about all the components 30 in the board | substrate 10, the board | substrate defect determination whether the board | substrate 10 is defective is performed. That is, if it is determined that there is a defect for at least one component 30, it is determined that the substrate is defective, and if it is determined that there is no defect for all the components 30, it is determined that the substrate is not defective.

[Example of process procedure for component mounting system]
FIG. 14 is a flowchart showing an example of a process procedure for one substrate 10 performed by the component mounting system 1 shown in FIG. First, the solder printing apparatus 2 performs solder printing as a solder printing process (step S101). As a result, the solder 21 is applied to the pads 11 of the substrate 10.

  Next, the solder measuring device 3 measures the solder volume, the solder outer shape, and the solder printing position for each solder 21 applied to the substrate 10 to which the solder 21 is applied by the solder printing device 2 (step S102). And the solder measuring device 3 produces | generates the solder information 210 containing these measurement results, and outputs it to the board | substrate inspection apparatus 100 (step S103).

  In response to the component mounting step, the component mounting apparatus 4 mounts the component 30 on the board 10 for which the measurement by the solder measuring device 3 has been completed (step S104).

  Next, the component measuring apparatus 5 measures the component outer shape and the component mounting position for each component 30 mounted on the substrate 10 on which the component 30 is mounted (step S105). Then, the component measuring apparatus 5 generates solder information 210 including these measurement results and outputs it to the board inspection apparatus 100 (step S106).

  The board inspection device 100 acquires the solder information 210 output from the solder measurement device 3 in step S103 and the component information 220 output from the component measurement device 5 in step S106. Then, the board defect determination is performed using the acquired solder information 210 and component information 220 (step S107).

  The substrate inspection apparatus 100 determines whether or not a determination result that there is a substrate defect is obtained by the substrate defect determination in step S107 (step S108). Here, when it is determined that there is no substrate defect (step S108—NO), the substrate 10 is carried into the reflow furnace 6. The reflow furnace 6 performs a reflow process of heating and soldering the carried substrate 10 (step S109). On the other hand, when it is determined that there is a substrate defect, the notification control unit 115 in the substrate inspection apparatus 100 performs control for notification according to the occurrence of the substrate defect without sending the substrate 10 to the reflow process in step S109. (Step S110).

  As described above, in this embodiment, it is possible to determine a substrate defect in a stage before the reflow process. For example, in Patent Document 1, a substrate defect inspection is performed after a reflow process. If a defect is detected on the board after the component mounting is completed (after the reflow process), the parts are removed from the board and reattached. However, after the reflow process, the parts Since it is already joined by the pad and the solder, it is necessary to remove the component by melting the solder, which is troublesome. On the other hand, if a defect can be detected at the previous stage of the reflow process as in this embodiment, since the soldering has not been completed yet, the removal work of the components mounted on the board is very easy. Manufacturing efficiency is improved.

[Processing procedure example of substrate inspection equipment]
The flowchart in FIG. 15 shows an example of a processing procedure executed by the substrate inspection apparatus 100 for the substrate defect determination in step S107 in FIG. The processing shown in this figure can be regarded as being executed by the functional unit in the CPU 101 shown in FIGS.

  First, the solder information acquisition unit 111 acquires the solder information 210 output from the solder measuring device 3 in step S103 of FIG. 14 (step S201). The acquired solder information 210 is stored in the RAM 102 as described above.

  Further, the part information acquisition unit 112 acquires the part information 220 output from the part measuring apparatus 5 in step S106 of FIG. 14 (step S202). The acquired solder information 210 is stored in the RAM 102.

  Next, the evaluation value calculation unit 113 selects one component 30 to be determined (step S203). Then, predetermined information associated with the determination target component 30 is read from the solder information 210 and the component information 220 stored in the RAM 102 (step S204). That is, from the solder information 210, the solder outline, the solder printing position, and the solder volumes Va and Vb corresponding to the pads 11a and 11b of the determination target component 30 are read. Further, from the component information 220, the component outer shape and the component mounting position corresponding to the component 30 to be determined are read.

  Next, the contact area calculation unit 121 of the evaluation value calculation unit 113 uses the solder outer shape, the solder printing position, the component outer shape, and the component mounting position read as described above for each of the pads 11a and 11b as described above. The contact areas Sa and Sb corresponding to are calculated (step S205).

  The multiplication unit 122 of the evaluation value calculation unit 113 multiplies the contact area Sa and the solder volume Va to obtain a multiplication value SVa corresponding to the pad 11a, and multiplies the contact area Sb and the solder volume Vb to correspond to the pad 11b. A multiplication value SVb is obtained (step S206). Then, the evaluation value calculation unit 123 of the evaluation value calculation unit 113 calculates the evaluation value E as described above by using the multiplication values SVa and SVb (step S207).

  The defect determination unit 114 determines whether or not (E ≦ th) is established as described above for the evaluation value E and the threshold value th calculated as described above (step S208). When (E ≦ th) is satisfied (step S208—YES), the defect determination unit 114 determines that there is no defect in component floating for the component 30 to be determined (step S209). On the other hand, when (E ≦ th) is not established (step S208—NO), the defect determination unit 114 determines that there is a component floating defect for the determination target component 30 (step S210).

  After the determination in step S209 or S210, the defect determination unit 114 determines whether or not the defect determination for all the components 30 in the substrate 10 that is the substrate defect determination target is completed (step S211). Here, if there is a part 30 that has not yet been determined to be defective (step S211—NO), the process returns to step S203 to shift to a defect determination process for the next determination target part 30.

  On the other hand, when the defect determination for all the components 30 is completed (step S211—YES), the defect determination unit 114 obtains a determination result indicating no defect for all the components by the defect determination for each component 30 thus far. It is determined whether or not it has been (step S212). Here, when it is determined that the determination result of no defect is obtained for all the components 30 (step S212—YES), it is determined that there is no substrate defect (step S213). On the other hand, when a determination result indicating that there is a defect is obtained for at least one component 30 (step S212—NO), the defect determination unit 114 determines that there is a substrate defect (step S214).

  The above-described substrate inspection apparatus has a computer system inside. The defect determination process described above is stored in a computer-readable recording medium in the form of a program, and the above processing is performed by the computer reading and executing this program. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  Further, in the present embodiment, a program for realizing the function of the processing unit in FIG. 7 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. You may perform defect determination. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer system” includes a WWW system having a homepage providing environment (or display environment). The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

DESCRIPTION OF SYMBOLS 1 Component mounting system 2 Printing apparatus 3 Solder measuring apparatus 4 Component mounting apparatus 5 Component measuring apparatus 6 Reflow furnace 10 Substrate 11, 11a, 11b Pad 30 Component 31, 31a, 31b Electrode 100 Substrate inspection apparatus 111 Solder information acquisition part 112 Component information Acquisition unit 113 Evaluation value calculation unit 114 Defect determination unit 115 Notification control unit 121 Contact area calculation unit 122 Multiplying unit 123 Evaluation value calculation unit

Claims (8)

A solder information acquisition unit for acquiring solder information including a solder volume as a measurement result for solder applied to a pad of a substrate by a solder printing process;
A component information acquisition unit that acquires component information including measurement results for components mounted on the substrate by a component mounting step after the solder printing step;
Based on the solder information and the component information, a contact area between the determination target component and the pad is calculated, and based on the calculated contact area and the solder volume, a soldering failure in the determination target component An evaluation value calculation unit for obtaining an evaluation value used to determine the presence or absence of
A board inspection apparatus, comprising: a failure determination unit that determines whether or not there is a soldering defect for each of the determination target components based on the evaluation value. The solder information further includes, as a measurement result for the solder, a solder outer shape indicating the outer shape of the solder, and a solder printing position indicating coordinates on the substrate to which the solder is applied,
The component information includes, as a measurement result for the component, a component outer shape indicating the outer shape of the component, and a component mounting position indicating coordinates on the board on which the component is mounted,
The evaluation value calculation unit
The board inspection apparatus according to claim 1, wherein the contact area for each determination target component and pad is calculated based on the solder outer shape, the solder printing position, the component outer shape, and the component mounting position. . The evaluation value calculation unit
The board inspection apparatus according to claim 2, wherein an evaluation value is obtained based on a multiplication value obtained by multiplying the contact area for each part to be determined and the pad by the solder volume. The evaluation value calculation unit
The board inspection apparatus according to claim 3, wherein a ratio of differences in the multiplication values obtained corresponding to each pad to which the determination target component is bonded is obtained as an evaluation value. 5. The substrate according to claim 1, wherein the defect determination unit determines that there is no defect in the substrate when it is determined that there is no defect in soldering of all components on the substrate. Inspection device. A solder printing apparatus for performing a solder printing process for applying solder to the pads of the substrate;
Measuring the solder applied by the solder printing device, and a solder measuring device that generates solder information including the solder volume as a measurement result;
A component mounting device for performing a component mounting step of mounting a component on the substrate to which solder has been applied by the solder printing device;
A component measurement device that performs measurement on the component mounted by the component mounting device and generates component information including the measurement result; and
A reflow furnace for performing a reflow process of soldering the mounted component to the pad by heating the substrate on which the component is mounted by the component mounting apparatus to melt the solder;
A board inspection device for inspecting a soldering failure in the board;
The substrate inspection apparatus includes:
A solder information acquisition unit for acquiring the solder information from the solder measuring device;
A component information acquisition unit for acquiring the component information from the component mounting device;
Based on the solder information and the component information, a contact area between the determination target component and the pad is calculated, and based on the calculated contact area and the solder volume, a soldering failure in the determination target component An evaluation value calculation unit for obtaining an evaluation value used to determine the presence or absence of
A component mounting system comprising: a defect determination unit that determines whether or not there is a soldering defect for each determination target component based on the evaluation value. A solder information acquisition step for acquiring solder information including a solder volume as a measurement result for solder applied to a pad of a substrate by a solder printing process;
A component information acquisition step for acquiring component information including measurement results for components mounted on the substrate by a component mounting step after the solder printing step;
Based on the solder information and the component information, a contact area between the determination target component and the pad is calculated, and based on the calculated contact area and the solder volume, a soldering failure in the determination target component An evaluation value calculating step for obtaining an evaluation value used to determine the presence or absence of
And a failure determination step of determining whether or not there is a soldering failure for each of the determination target components based on the evaluation value. Computer
Solder information acquisition means for acquiring solder information including the solder volume as a measurement result for the solder applied to the pad of the substrate by the solder printing process;
Component information acquisition means for acquiring component information including measurement results for components mounted on the substrate by a component mounting step after the solder printing step;
Based on the solder information and the component information, a contact area between the determination target component and the pad is calculated, and based on the calculated contact area and the solder volume, a soldering failure in the determination target component Evaluation value calculation means for obtaining an evaluation value used to determine the presence or absence of
A program that functions as a failure determination unit that determines whether or not there is a soldering failure for each determination target component based on the evaluation value.

Images