JP6029162B2 - Defect inspection device, component mounting system, defect inspection method, program - Google Patents

Description

  The present invention relates to a defect inspection apparatus, a defect inspection method, and a program for inspecting a soldering defect of a printed board. The present invention also relates to a component mounting system including a defect 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 printed circuit board, and components are fixed and connected by soldering to the mounting surface, rather than forming a component mounting hole in the printed circuit board. . Component mounting on the board 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 floating is a phenomenon in which one end of a chip-type component is lifted (rises) from the substrate.

  The following techniques are known for inspecting defects caused by the above-mentioned component floating. In other words, the printed circuit 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 if the floating defect is detected, the captured image of the component mounting process is used. The presence / absence of solder bleeding is determined, and when there is solder bleeding, the cause of the floating defect is specified as an excessive amount of solder paste in the solder printing process (see, for example, Patent Document 1).

JP 2006-324424 A

  With the technique described in Patent Document 1, it is possible to identify the cause of the floating defect based on the captured image for each process in the SMT. However, this technique is performed in order to efficiently implement subsequent countermeasures and quality control, and no consideration is given to detecting a defect in the middle of the process until component mounting is completed.

  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 dissolving the solder, which is troublesome. On the other hand, if the defect can be detected in the previous stage of the reflow process, the soldering has not been completed yet, so the removal work of the components mounted on the board becomes very easy and the production efficiency is improved. It is preferable to improve.

  Therefore, an object of the present invention is to provide a defect inspection apparatus, a component mounting system, a defect inspection method, and a program that can solve the above-described problems.

The present invention has been made to solve the above-described problems, and a defect inspection apparatus according to one aspect of the present invention provides solder to each pad, which is two soldering locations corresponding to one component, by a solder printing process. A printed circuit board solder information generation unit that generates printed circuit board solder information that stores at least the solder area of each pad position on the printed circuit board from the printed circuit board image data obtained by imaging the applied printed circuit board, and a component mounting process from the component mounting board image data obtained by imaging the printed circuit board equipped with the components with respect to each pad the solder has been applied, the component mounting of storing at least the solder area of each pad position in the printed circuit board a component mounting board solder information generation unit for generating a substrate solder information, the determination target component corresponding to the two pads position to be joined A solder area acquired from the printed substrate solder information, the determination target component based on the solder area acquired from the component mounting board solder information corresponding to the two pads to be bonded, of said two pads and variation before and after the component mounting process of the solder area of one pad, corresponding to each pad position to said determination target component the difference between the variation amount of the component mounting step before and after the solder area of the other pad is bonded and calculated, and the variation of the absolute value and the defect determining unit for determining the presence or absence of a defective component mounting of the printed circuit board based on a comparison with a preset threshold of the difference for each pad, which is the calculated wherein the defect determining unit, when the solder area based failure determination is not there bad, further, the component mounting step after with the pads to the determination target component is joined And judging the presence or absence of a failure based on the solder protrusion amount.

A component mounting system according to an aspect of the present invention includes a solder printing apparatus that performs a solder printing process for applying solder to pads on a printed circuit board, and two soldering locations corresponding to one component by the solder printing apparatus. A printed circuit board imaging device that captures an image of a printed circuit board in which solder is applied to each pad and generates printed circuit board image data, and a component for each pad of the printed circuit board in which solder is applied by the solder printing device a component mounting device for performing component mounting step of mounting, the component mounting board imaging device for generating component mounting board image data printed board on which the component is mounted by the component mounting apparatus by imaging, the by the component mounting device The printed circuit board on which the component is mounted is heated to melt the solder, whereby the mounted component is soldered to the pad. Comprising a reflow furnace to perform low step, a defect inspection device, the failure inspection apparatus, from the printed substrate image data, generates print substrate solder information storing at least the solder area of each pad position in the printed circuit board printed The board solder information generating section, the printed board solder information generating section for generating the component mounting board solder information for storing at least the solder area of each pad position on the printed board from the component mounting board image data, and the determination target component are joined. Solder area acquired from the printed board solder information corresponding to the two pad positions to be performed and solder area acquired from the component mounting board solder information corresponding to the two pads to which the determination target component should be bonded based on the bets, and the variation amount after the component mounting process prior to solder area of one pad of the two pads, the other path The difference between the component mounting process of the variation before and after the solder area of de calculated corresponding to each pad position to said determination target component are joined, the difference between the variation amount of each pad is the calculated and a absolute value with a preset defect determining unit for determining the presence or absence of a defective component mounting of the printed circuit board on the basis of a comparison with the threshold value, the defect determination unit, the defect determination result based on the solder area bad If not, it is further characterized in that the presence / absence of a defect is determined based on the amount of solder protruding after the component mounting process on the pad to which the determination target component is to be bonded.

Also, the defect inspection method as one aspect of the present invention is a printed circuit board image obtained by imaging a printed circuit board in which solder is applied to each pad, which is two soldering locations corresponding to one component, by a solder printing process. from the data, and the print substrate solder information generation step of generating print substrate solder information storing at least the solder area of each pad position in the printed circuit board, said component relative to said each pad the solder has been applied by the component mounting process A component mounting board solder information generating step for generating component mounting board solder information for storing at least the solder area of each pad position on the printed circuit board from the component mounting board image data obtained by imaging the printed board on which , acquired from the printed board solder information determination target component corresponding to the two pads position to be joined half Area and the determination target component based on the solder area acquired from the component mounting board solder information corresponding to the two pads to be bonded, part of the solder area of one pad of said two pads and variation before and after mounting process, is calculated to correspond to each pad position to said determination target component is bonded to the difference between the other component mounting process of the variation before and after the solder area of the pad, is the calculated and a failure determining step to determine the presence or absence of a defective component mounting of the printed circuit board based on a comparison of the absolute value with a preset threshold value of the variation of the difference for each pad, in the defect determining step further, when a defect determination result based on the solder area is not there bad, further, the determination target component half after the component mounting process for the pad to be bonded And judging the presence or absence of a failure based on the amount of protrusion of.

The program as one aspect of the present invention is a printed circuit board obtained by imaging a printed circuit board in which solder is applied to each pad, which is two soldering locations corresponding to one component, by a solder printing process. from the image data, the print substrate solder information generation means for generating print substrate solder information storing at least the solder area of each pad position in the printed circuit board, said component relative to said each pad the solder has been applied by the component mounting process Component mounting board solder information generating means for generating component mounting board solder information for storing at least the solder area of each pad position on the printed circuit board from the component mounting board image data obtained by imaging the printed board mounted with obtained from the printed board solder information determination target component corresponding to the two pads position to be joined And field area, the determination target component based on the solder area acquired from the component mounting board solder information corresponding to the two pads to be joined, the solder area of one pad of said two pads and variation before and after the component mounting process, is calculated to correspond to each pad position to said determination target component is bonded to the difference between the component mounting process variation amount before and after the solder area of the other pad, the calculated to function as a defect determination unit for determining the presence or absence of a defective component mounting of the printed circuit board based on a comparison of the absolute value with a preset threshold value of the variation of the difference for each pad that is, the defect determination unit further when the solder area based failure determination is not there bad, further, the solder leaf blade after the component mounting process for the pad to the determination target component is joined It determines the presence or absence of defects based on the amount and.

  According to the present invention, it is possible to provide a defect inspection apparatus capable of detecting a soldering defect in the middle of the component mounting process.

It is a figure which shows the structural example of the component mounting system containing the defect inspection apparatus as embodiment of this invention. It is a figure which shows the example of a state of the component according to the floating defect resulting from the inclination of the component at the time of mounting | wearing, and solder. It is a figure which shows the example of a cause in which components tilt at the time of mounting | wearing. It is a figure which shows the example of a change of the solder area after the solder printing process and component mounting process in FIG. It is a figure which shows the example of a state of the components according to the floating defect resulting from the imbalance of the amount of solder at the time of solder printing, and solder. It is a figure which shows the example of the state of the components and solder which are considered to be without generating defect even if the solder protrudes from the pad. It is a figure which shows the structural example of the defect inspection apparatus in this embodiment. It is a figure which shows the function structural example of the defect inspection apparatus in this embodiment. It is a figure which shows the structural example of printed circuit board solder information or component mounting board solder information. It is a figure which shows the example of a process sequence which a defect inspection apparatus performs. It is a figure which shows the example of a procedure of the defect determination process which a defect determination part performs.

[Component mounting system configuration]
FIG. 1 shows a configuration example of a component mounting system 1 including a defect inspection apparatus 100 of the present embodiment. The component mounting system 1 according to the present embodiment performs component mounting by soldering a component to an appropriate position on a printed circuit 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). The SMT is a method of fixing and connecting a component by mounting the component on a printed circuit board and soldering the component mounting surface on the circuit board. The solder printing process, the component mounting process, and the reflow process are performed. Proceed in order.

  The solder printing process is a process of applying cream-like solder to electrodes called pads formed on the printed circuit board. 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 printed circuit board on which the component is mounted, thereby fixing the component to the printed circuit board.

  The component mounting system 1 according to the present embodiment includes a solder printing device 2, a component mounting device 3, a reflow furnace 4, a transport device 5, a transport device 6, a printed board imaging device 7, a component mounting substrate imaging device 8, and a defect inspection device 100. Become.

  The solder printing apparatus 2 is an apparatus that executes an operation as a solder printing process. A printed circuit board 10 on which a pad pattern as a conductor to which a component is fixed is formed is carried into the solder printing apparatus 2. The solder printing apparatus 2 performs screen printing for applying cream-like solder to the pad of the printed board 10 that is carried in.

  The printed circuit board 10 discharged from the solder printing apparatus 2 after the solder application is completed is delivered to the transport apparatus 5. The transport device 5 transports the transferred printed board 10 to the component mounting device 3.

  The printed circuit board 10 with the solder applied on the pads as described above is carried into the component mounting device 3 by the transport device 5. The component mounting apparatus 3 mounts components so as to be placed on a pad position where solder is applied on the carried-in printed circuit board 10.

  The printed circuit board 10 carried out from the component mounting device 3 after the component mounting is completed is delivered to the transport device 6. The transport device 6 transports the delivered printed circuit board to the reflow furnace 4.

  A printed circuit board 10 on which components are mounted is carried into the reflow furnace 4 by the transport device 6. The reflow furnace 4 performs soldering by melting the solder by heating the entire loaded printed circuit board 10 at a predetermined temperature and time, and fixing components to the printed circuit board 10 and electrically connecting the pads. . As a result, the printed circuit board 10 mounted with components fixed is discharged from the reflow furnace 4.

  The printed circuit board imaging device 7 captures the surface of the substrate to which the solder is applied for each printed circuit board 10 at the stage where the solder printing process by the solder printing device 2 is completed, and generates image data. The image data generated in this way is output to the defect inspection apparatus 100 as printed circuit board image data indicating the state after the solder printing process for each printed circuit board 10. In this embodiment, the printed circuit board imaging device 7 is provided so that the printed circuit board 10 in the middle of conveyance can be imaged by the conveyance device 5.

  In addition, the component mounting board imaging device 8 has a board surface on which the solder is applied and the components are mounted for each printed board 10 at the stage where the component mounting process by the component mounting apparatus 3 is completed (the printed board imaging device 7 takes an image). Image data is generated by imaging from the plane direction. The image data generated in this way is output to the defect inspection apparatus 100 as component mounting board image data indicating the state after the component mounting process for each printed circuit board 10. Further, it is assumed that the component mounting board imaging device 8 is provided so that the printed board 10 in the middle of conveyance can be imaged by the conveyance device 6.

  The defect inspection apparatus 100 uses the component mounting board image data output from the printed board imaging device 7 and the component mounting board image data output from the component mounting board imaging device 8 at a stage after the component mounting process. An inspection for defective component mounting on the printed circuit board 10 is performed.

[Causes of defects]
Prior to describing the configuration for defect inspection by the defect inspection apparatus 100 according to the present embodiment, the cause of the occurrence of a defect to be inspected by the defect inspection apparatus 100 will be described. A typical component mounting defect in SMT is a floating defect.

  FIG. 2 shows an example of a process in which a floating failure occurs. 2 (a) and 2 (b) show a state in which the solder 20a and 20b are applied to each of the pads 11a and 11b in the printed circuit board 10 by the solder printing process, respectively, according to a plan view and a side view. Show. The pads 11a and 11b are in a pair relationship, and the same component is mounted on each of the pads 11a and 11b. That is, the component 30 includes two electrodes 31 at both ends thereof. Then, one of the two electrodes 31 is soldered to the pad 11a, and the other electrode 31 is soldered to the pad 11b so that the component is fixed at a position corresponding to the pads 11a and 11b. It is what is done.

  According to FIG. 2A, the areas of the solder 20a and the solder 20b are substantially the same in the pads 11a and 11b, respectively. Further, according to FIG. 2B, the heights of the solder 20a and the solder 20b are shown to be the same. This indicates that the application amounts (that is, volumes) of the solder 20a and the solder 20b are the same.

  In order to avoid component mounting defects, it is required that the amount of solder applied to a plurality of pads corresponding to the same component be as much as possible. When the amount of solder applied to each pad becomes unbalanced, the contact area between the solder and the component electrode 31 for each pad also becomes unbalanced. If the reflow process is performed in this state, a difference occurs in the surface tension when the solder is melted, and the component is attracted to the pad having the higher surface tension. As a result, the component is liable to float on the pad having a weak surface tension.

  However, even if the same amount of solder 20a, 20b is applied as shown in FIGS. 2 (a) and 2 (b), a defect may occur due to a failure in the next component mounting process. 2 (c) and 2 (d) show a plan view and a side view of the portions of the pads 11a and 11b at the stage where the component mounting process has been completed. 2 (c) and 2 (d) show a state in which the component 30 is mounted on the solders 20a and 20b applied to the pads 11a and 11b from above. Yes. The component 30 is also called a chip component, and includes electrodes 31 and 31 at both ends thereof.

  There is a problem in the mounting state of the component 30 shown here. In other words, the component 30 should be placed so as to be in a substantially horizontal posture on the solders 20a and 20b. However, as shown in FIG. 2D, the component 30 in this case is placed so as to be inclined toward the solder 20b rather than the solder 20a.

  An example of the cause of the inclination of the mounting posture of the component 30 will be described with reference to FIG. In FIG. 3, the nozzle 40 is a part that is provided in the component mounting apparatus 3 and sucks and lifts the component 30 in order to transport the component 30 to the mounting position. If the foreign object 50 is present between the nozzle 40 and the component 30 when the nozzle 40 tries to suck the component 30, the component 30 is lifted while the foreign object 50 is sandwiched, and the component 30 tilts. End up. Then, when the component 30 is transported to the mounting position and mounted in this state, the component 30 is pressed against the solders 20a and 20b in an inclined posture. For example, due to this, the mounting posture of the component 30 is inclined.

  As described above, when the component 30 is mounted inclined to the solder 20b side, the degree of pressing of the component 30 against the solder 20b is larger than that of the other solder 20a side. FIG. 4A shows the state of the solders 20a and 20b on the pads 11a and 11b after the solder printing process similar to that shown in FIG. In FIG. 4B, the component 30 is not shown in the state after the component mounting step shown in FIG. 2C for convenience of explanation. That is, FIG. 4B shows the state of the solders 20a and 20b corresponding to the situation of FIGS. 2C and 2D.

  After the solder printing process shown in FIG. 4A, the area Sa1 of the solder 20a applied to the pad 11a and the area Sb1 of the solder 20b applied to the pad 11b are the same. However, after the component mounting process of FIG. 4B, the component 30 is tilted and mounted to the solder 20b side as shown in FIG. 2D, so that the solder 20b is more than the component 20 than the solder 20a. The degree of being pushed in increases. Along with this, the solder 20b is larger in the planar direction due to the component 30 being pushed in than the solder 20a. As a result, as shown in FIG. 4B, the area Sa2 of the solder 20a after the component mounting process does not change so much with respect to the area Sa1 after the solder printing process, but after the component mounting process. The area Sb2 of the solder 20b is considerably larger than the area Sb1 after the solder printing process.

  As the area Sb2 is increased in this way, the contact area between the component 30 and the solder 20b becomes larger than that on the solder 20a side. Can occur.

FIGS. 2 (e) and 2 (f) show a state where floating occurs as a result of the reflow process from the state of FIGS. 2 (c) and 2 ( d ). In this figure, since the surface tension of the solder 20b is larger than that of the solder 20a in a state where the solders 20a and 20b are melted, the component 30 is pulled and biased toward the solder 20b. The state where the floating defect which 30 electrodes 31 were not joined reliably is shown.

  In addition, with reference to FIG. 5, the floating defect due to the unbalance of the solder application amount will be described. The plan view of FIG. 5A and the side view of FIG. 5B show a state in which the solders 20a and 20b are applied to the pads 11a and 11b, respectively, after the solder printing process.

  According to the plan view of FIG. 5A, the areas Sa1 and Sa2 of the solders 20a and 20b are the same, but as shown in the side view of FIG. 5B, the solder 20b is more than the solder 20a. Thickness (height) is large. This means that the application amounts of the solder 20a and the solder 20b are unbalanced.

  Next, FIG. 5 (c) and FIG. 5 (d) show a state in which the component 30 is mounted by the component mounting process from the state of FIG. 5 (a) and FIG. 5 (b). In this case, it is assumed that the component 30 is normally mounted without tilting itself. However, since the amount of the solder 20b is excessive, as shown in FIG. 5D, the component 30 is pushed in at a higher degree on the solder 20b side than on the solder 20a side. As a result, as shown in FIG. 5C, the area Sb2 of the solder 20b as viewed from the planar direction is larger than the area Sa2 of the solder 20a.

  Therefore, in FIGS. 5 (c) and 5 (d), the same solder 20a and 20b as in FIGS. 4 (c) and 4 (d) are provided. The contact area of the solder 20b is also larger.

  Thus, when the reflow process is performed from the state shown in FIGS. 5C and 5D, the difference in surface tension generated between the solder 20a and the solder 20b melted as described above is caused by the difference in the surface tension shown in FIG. ) And a floating defect occur as shown in FIG. Thus, the imbalance of the coating amount in the solder printing process also causes the occurrence of floating defects.

  In addition, with reference to FIG. 6, a state where the amount of solder applied tends to be excessive but not defective will be described. FIG. 6A shows the pads 11a and 11b after the solder printing process. In this case, it is assumed that the amount of the solder 20a and 20b applied to the pads 11a and 11b is the same, although it tends to be excessive. At this time, it is assumed that the area Sa1 of the solder 20a and the area Sb1 of the solder 20b in the planar direction are the same.

  FIG. 6B shows a state after the component mounting process is performed from the above state. In this case, it is assumed that the component 30 is normally mounted without tilting. When the mounted component 30 pushes in the solders 20a and 20b, the solders 20a and 20b expand to some extent in the planar direction. Here, since the application amounts of the solders 20a and 20b tend to be excessive, both the solders 20a and 20b are in a state of protruding from a part of the pads 11a and 11b. However, as described above, since the solder 20a and the solder 20b have the same amount, the area Sa2 of the solder 20a and the area Sb2 of the solder 20b shown in FIG. 6B are larger than the areas Sa1 and Sb1, respectively. Big but equal to each other.

  FIG. 6C shows a state after the reflow process is performed from the state of FIG. In this case, although the application amounts of the solders 20a and 20b tended to be excessive, the areas Sa2 and Sb2 of the solder 20a and the solder 20b after the component mounting process are equal as shown in FIG. 6B. Yes. For this reason, there is no floating defect.

  On the other hand, since the solder 20a and the solder 20b are once melted in the reflow process, the extent of the protrusion from the pads 11a and 11b is larger than the state of FIG. However, when the solder 20a and the solder 20b are protruded from the pads 11a and 11b to the extent shown in FIG. 6C, no short circuit occurs between the pads, and therefore it does not lead to a failure. In this way, even if the amount of solder applied is excessive, if the amount of solder protruding from the pad is below an allowable level, it will not be defective.

[Configuration example of defect inspection device]
The defect inspection apparatus 100 of the present embodiment detects the component mounting failure described with reference to FIGS. 2 and 4 at a stage after the component mounting process, that is, a stage before the reflow process. Further, even if the solder 20a, 20b protrudes from the pads 11a, 11b, it is detected that the state described with reference to FIG. 6 is not defective. Hereinafter, the configuration of the defect inspection apparatus 100 for this purpose will be described.

  FIG. 7 shows a configuration example of the defect inspection apparatus 100. The defect 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 defect 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 printed board imaging device 7 and the component mounting board imaging device 8 are connected to the data interface 106. Thereby, the defect inspection apparatus 100 can input the printed board image data generated by the printed board imaging apparatus 7 and the component mounting board image data generated by the component mounting board imaging apparatus 8 via the data interface 106. it can. The configuration shown in FIG. 7 can be realized by a computer device, for example.

[Example of functional configuration of defect inspection device]
FIG. 8 shows a configuration example of a functional unit realized by the CPU 101 of the defect inspection apparatus 100 executing a program. As illustrated, the CPU 101 includes a printed board image data acquisition unit 111, a printed board solder information generation unit 112, a component mounting board image data acquisition unit 113, a component mounting board solder information generation unit 114, a defect determination unit 115, and a notification control unit. Each function as 116 is provided. Also, in the drawing, among the data stored in the RAM 102, printed board solder information 210 and component mounting board solder information 220 are shown as data used by the CPU 101 for defect determination.

  The printed circuit board image data acquisition unit 111 acquires the printed circuit board image data input via the data interface 106.

  The printed circuit board image data is obtained by the printed circuit board imaging device 7 imaging the surface of the printed circuit board 10 on the printed circuit board 10 after the solder printing process from the plane direction as described above. That is, the image of the printed circuit board image data shows the solder application state for each pad. The printed circuit board solder information generation unit 112 generates printed circuit board solder information 210 reflecting the solder application state for each pad of the printed circuit board 10 from the printed circuit board image data, and stores it in the RAM 102.

  Further, the component mounting board image data acquisition unit 113 acquires the component mounting board image data input via the data interface 106.

  The component mounting board image data is obtained by imaging the board surface on which the pads are formed on the printed board 10 after the component mounting process from the plane direction. Therefore, the image of the component mounting board image data shows the solder application state that has changed due to the mounting of the components for each pad. The component mounting board solder information generation unit 114 generates component mounting board solder information 220 that reflects the solder application state after component mounting for each pad of the printed circuit board 10 from the component mounting board image data, and stores it in the RAM 102. .

  In the present embodiment, the printed board solder information 210 and the component mounting board solder information 220 are assumed to have the same structure. FIG. 9 shows a structural example of the printed board solder information 210 and the component mounting board solder information 220.

  As shown in the figure, the printed board solder information 210 and the component mounting board solder information 220 include process identifier areas 211 and 221, board identifier areas 212 and 222, component identifier areas 213 and 223, pad information areas 214 and 224, and a solder area area. It consists of 215 and 225 areas.

  The process identifier areas 211 and 221 store an identifier for identifying a process completed in the immediately preceding stage. In the case of the printed board solder information 210, an identifier indicating a solder printing process is stored. In the case of the component mounting board solder information 220, an identifier indicating a component mounting process is stored.

  The board identifier areas 212 and 222 store board identifiers for individually identifying the printed board 10 corresponding to the printed board solder information 210 or the component mounting board solder information 220. The printed board solder information 210 and the component mounting board solder information 220 having the same board identifier areas 212 and 222 correspond to the same printed board 10 respectively.

  The component identifier areas 213 and 223 store a component identifier assigned to each component mounted on the corresponding printed circuit board 10. The pad information areas 214 and 224 store predetermined information related to the pads, including a pad position indicating the position of each pad formed on the corresponding printed circuit board 10. By associating the component identifier areas 213 and 223 with the pad positions stored in the pad information areas 214 and 224, it is possible to identify the component on which each pad is mounted correspondingly.

  The solder area regions 215 and 225 store solder areas indicating the areas of the solder applied to the pads indicated by the pad position information stored in the corresponding pad information regions 214 and 224. Specifically, this solder area corresponds to the solder areas Sa1, Sb1, Sa2, Sb2, etc. described in FIG. The solder area can be shown as the number of pixels forming an image portion of solder as will be described later. However, for example, when it is assumed that the shape of the solder in the plane direction is a square, the adjacent sides Px and Py of the solder 20a may be stored as shown in FIG.

  As an example, the printed circuit board solder information generation unit 112 generates the printed circuit board solder information 210 having the structure described above. Although illustration is omitted, it is assumed that the storage unit 103 stores a database that stores various types of information about boards on which components are mounted by the component mounting system 1.

  The printed board solder information generation unit 112 reads the board identifier of the printed board currently being subjected to the solder printing process, the component identifier associated with the board identifier, and the pad position information from the database. Then, the board identifier, component identifier, and pad position information that have been read are stored in the board identifier area 212, the component identifier area 213, and the pad information area 214, respectively. The process identifier area 211 stores a process identifier value set in advance corresponding to the solder printing process.

  Next, the printed circuit board solder information generation unit 112 obtains the solder area stored in the solder area region 215 as follows. The printed circuit board solder information generation unit 112 collates the image of the printed circuit board 10 in the printed circuit board image data with each pad position stored in the pad information area 214. Thereby, the pad in the printed board image data is associated with the pad position stored in the pad information area 214. Thereby, the correspondence between the pad position and the component in the printed board image data is recognized.

  In addition, the printed board solder information generation unit 112 calculates the solder area for each pad position recognized as described above in the image of the printed board image data. There are several possible methods for calculating the solder area, but as an example, solder is applied from the printed circuit board image data using pixel value information registered in advance as corresponding to the image portion of the solder. Specify the solder area. Then, the number of pixels forming this solder region is obtained. It is conceivable that the number of pixels obtained in this way is used as the solder area.

  The printed board solder information generation unit 112 generates the printed board solder information 210 shown in FIG. 9 based on the process identifier, board identifier, component identifier, pad position, and solder area acquired as described above.

  The generation process of the component mounting board solder information 220 by the component mounting board solder information generation unit 114 is also similar to the processing of the printing board solder information 210 by the printing board solder information generation unit 112. However, since the solder area in the component mounting board image data is partially hidden by the component, when the number of pixels having a pixel value corresponding to solder is directly obtained as the solder area, the actual solder It becomes smaller than the area. Therefore, in this case, the number of pixels as the solder area may be obtained after estimating the solder portion hidden by the component by interpolation processing or the like and specifying the entire solder region.

  Returning to FIG. The defect determination unit 115 determines whether or not there is a component mounting defect of solder based on the printed board solder information 210 and the component mounting board solder information 220. An example of a failure determination method performed by the failure determination unit 115 will be described later.

  The notification control unit 116 performs control for notifying the operator of the occurrence of component mounting failure in response to the failure determining unit 115 determining that there is a component mounting failure. As a specific example, the notification control unit 116 outputs an alarm sound notifying that a component mounting failure has occurred from a speaker or the like in the output interface 105. In addition, information indicating the printed circuit board 10 in which a defect has occurred, information indicating a location in which a defect has occurred, and the like are displayed on a display device or the like in the output interface 105.

  An example of the defect determination by the defect determination unit 115 will be described again with reference to FIG. As described above, the pads 11a and 11b shown in FIG. 4A correspond to the same components. In addition, the states of the solders 20a and 20b applied to the pads 11a and 11b by the solder printing process are shown. FIG. 4B shows the state of the solder 20a, 20b after performing the component mounting process from the state of FIG.

  Here, the solder areas of the solders 20a and 20b applied to the pads 11a and 11b after the solder printing process of FIG. 4A are respectively solders corresponding to the pad positions of the pads 11a and 11b in the printed board solder information 210. It is stored in the area area 215. Similarly, the solder areas of the solders 20a and 20b applied to the pads 11a and 11b after the component mounting process of FIG. 4B correspond to the pad positions of the same pads 11a and 11b in the component mounting board solder information 220, respectively. The solder area region 225 is stored.

The defect determination unit 115 reads the solder areas Sa1 and Sb1 of the solders 20a and 20b applied to the pads 11a and 11b after the solder printing process from the printed board solder information 210. Further, from the component mounting board solder information 220, the solder areas Sa2 and Sb2 of the solders 20a and 20b applied to the pads 11a and 11b after the component mounting process are read. Then, it is determined whether or not the following expression holds for these solder areas and a preset threshold value th1.
| (Sb2-Sb1)-(Sa2-Sa1) | ≧ th1
The failure determination unit 115 determines that a failure has occurred if the above equation is satisfied, and determines that no failure has occurred if the above equation is not satisfied.

  The term (Sb2-Sb1) on the left side of the above equation indicates the difference in solder area between the solder printing process and the component mounting process for the solder 20b applied to the pad 11b. Further, the term (Sa2-Sa1) on the left side of the same equation indicates the difference in solder area after the solder printing process and after the component mounting process for the solder 20a applied to the pad 11a. Therefore, the left side of the above formula shows the difference between the change amount of the solder 20a and the change amount of the solder 20b between the solder printing process and the component mounting process.

  For example, as illustrated in FIG. 2, in the case where the area of the pad 11 b is greatly enlarged due to the component 30 being inclined and mounted (transition from FIG. 2 (a) to FIG. 2 (c)). Means that the value on the left side of the above formula increases and exceeds the threshold th1, for example. Further, as illustrated in FIG. 5, when the amount of solder applied is unbalanced, a difference occurs in the expansion of the solder area due to the mounting of the component 30 (from FIG. 5A to FIG. 5C). Also, the value of the left side of the above formula increases and exceeds the threshold value th1. As described above, the defect determination unit 115 uses the above equation to prevent component mounting defects caused by the inclination of the component 30 in the mounting process illustrated in FIG. 2 and the unbalance of the solder application amount illustrated in FIG. It can be judged accurately.

  Although illustration explanation is omitted, although the solder areas of the solders 20a and 20b applied to the pad 11a and the pad 11b in the solder printing process are different, the solder areas are the same after the component mounting process. There is a case. This can occur in the following cases. That is, after the solder printing process, the solder area may differ depending on the difference in the amount of solder 20a, 20b applied. When the component 30 is mounted in an inclined state from this state, there is a difference in the degree to which the component 30 pushes the solder, and as a result, the solder area may be approximately the same after the component mounting process. Such a state is also likely to cause a component mounting failure.

  According to the above equation, the difference in the amount of change in the solder area between the solder 20a and the solder 20b after the solder printing process and after the component mounting process is obtained. Even if the solder areas of the solder 20a and the solder 20b after the component mounting process are equal to each other, the amount of change in the solder area after the solder printing process and after the component mounting process is considerably different. Therefore, according to the above equation, it is possible to accurately determine the defect corresponding to the case where the solder application amount is originally unbalanced but the solder area becomes equal after the component mounting process. It becomes possible.

  As can be understood from the above description, the defect determination unit 115 performs defect determination using the solder area in each of the solder printing process and the component mounting process. This means that the printed board image data and the component mounting board image data are used in combination for the defect determination. As a result, as described above, it is possible to determine the amount of change in the solder area after the solder printing process and after the component mounting process for each pad, and the failure determination is performed based on the amount of change. By using the solder state change after the solder printing process and after the component mounting process in this way, in this embodiment, it is possible to accurately determine the defect before the reflow process. Thus, by detecting a defect in the stage before the reflow process, it is possible to very easily perform the operation of removing the component from the printed circuit board 10 for correcting the position of the component, leading to an improvement in manufacturing efficiency.

  In Patent Document 1, defect detection is performed from imaged image data of the printed circuit board after the solder printing process, after the component mounting process, and after the reflow process, but when detecting defects, imaging corresponding to each process is performed. The image data is used individually, and the difference of the captured image data between processes is not used. For this reason, according to the progress of the component mounting process, it is not possible to determine the defect in real time at the stage before the reflow process.

  Further, as described with reference to FIG. 6, the defect determination unit 115 has a case where the amount of protrusion is within an allowable range even if the solder 20 a and 20 b protrude from the pads 11 a and 11 b, and the solder areas of both are equal. It is preferable to determine that it is not defective. In this embodiment, it is possible to accurately determine the defect by the defect determination based on the difference between the pads in the solder area variation amount between the processes described above. In addition, the reliability of the failure determination result is further improved if the determination can be made so as not to erroneously detect the state of FIG.

Therefore, when it is determined that the above equation is satisfied, the defect determination unit 115 of the present embodiment does not immediately determine that the defect is not defective, but further makes the following determination. That is, it is determined whether or not the amount of protrusion of the solder 20a, 20b from the pad after the component mounting process is a certain amount or more. That is, for each of the solder 20a and the solder 20b, the solder area on each pad is calculated with respect to the pad area obtained from the design value of each pad, the pad area is PA, the solder area is SA, and outside the PA. The area of a certain SA is S_drop and the margin for the pad area is mg.
S_drop> mg
Whether or not is satisfied is determined.
It is assumed that the pad area PA is different for each pad. Therefore, the pad area PA may be stored together with the pad position in the pad information area 224 of the component mounting board solder information 220, for example, and read and acquired when the above formula is determined.

  If neither of the solders 20a and 20b is satisfied, the solders 20a and 20b do not protrude from the pads 11a and 11b, or even if they protrude, they are within an allowable range corresponding to the margin mg. Become. In addition, it is determined that the defect determination based on the amount of change in the solder area between the previous processes is not defective, and thus the difference in the solder areas of the solders 20a and 20b after the component mounting process is within an allowable range. I know. That is, the solder areas of the solders 20a and 20b may be regarded as being equal, and the amount of protrusion to the pad is within a certain range. Therefore, in this case, it is determined that there is no defect according to the description of FIG.

  On the other hand, when the above equation holds for at least one of the solders 20a and 20b, the amount of protrusion from the pad exceeds the allowable range for at least one of the solders 20a and 20b. Therefore, in this case, it is determined to be defective.

  As described above, in the present embodiment, it is possible to accurately determine the defect corresponding to the state shown in FIG. In Patent Document 1, only whether or not the solder protrudes from the pad is detected, and the failure determination is performed based only on the detection result, and the difference in the solder area between the pads corresponding to the same component is not taken into consideration. . For this reason, in Patent Document 1, although the solders 20a and 20b protrude from the pads 11a and 11b, the amount of protrusion is within an allowable range, so that it is defective even in a non-defective product. It will be judged.

[Example of processing procedure]
The flowchart of FIG. 10 shows an example of a processing procedure executed by the defect inspection apparatus 100. In this figure, the process performed by the component mounting system 1 of FIG. 1 corresponding to one printed circuit board 10 on which components are mounted through each process is shown. Further, the processing shown in this figure can be regarded as appropriately executed by the functional unit in the CPU 101 shown in FIG.

  First, the printed circuit board image data acquisition unit 111 acquires the printed circuit board image data input by the data interface 106 from the printed circuit board imaging device 7 (step S101). Next, the printed circuit board solder information generation unit 112 generates the printed circuit board solder information 210 from the printed circuit board image data acquired in step S101 and stores it in the RAM 102 (step S102).

  Further, the component mounting board image data acquisition unit 113 acquires the component mounting board image data input by the data interface 106 from the component mounting board imaging device 8 (step S103). The component mounting board image data acquired in step S103 is an image of the same printed circuit board 10 that was imaged by the printing board imaging device 7 in order to generate the printed board image data acquired in step S101. is there. Next, the component mounting board solder information generating unit 114 generates the component mounting board solder information 220 from the printed board image data acquired in step S103 and stores it in the RAM 102 (step S104).

  Next, the defect determination unit 115 executes defect determination processing for the printed circuit board 10 after the component mounting process using the printed circuit board solder information 210 and the component mounting board solder information 220 (step S105).

  The flowchart of FIG. 11 shows an example of a procedure for the defect determination process as step S105. First, the defect determination unit 115 acquires a solder area for each pad corresponding to one target component in the printed circuit board 10 to be determined from the printed circuit board solder information 210 (step S201). That is, in the printed board solder information 210, the board identifier of the judgment target printed board 10 and the solder area stored in the solder area 215 for each pad position corresponding to the component identifier selected as the target part are read and acquired. To do.

  Further, the defect determination unit 115 acquires, from the component mounting board solder information 220, a solder area for each pad corresponding to one component on the same printed circuit board 10 to be determined by processing according to step S201 (step S202). ).

Next, the defect determination unit 115 calculates a solder area change amount difference value α (step S203). The solder area change amount difference value α is a difference value between the change amounts after the solder printing process and after the component mounting process for each solder area on the pad corresponding to one component. That is, the left side of the equation shown above,
α = | (Sb2-Sb1)-(Sa2-Sa1) |
Can be obtained as follows.

Then, the defect determination unit 115 compares the solder area change amount difference value α with a preset threshold value th1,
α ≧ th1
Whether or not is satisfied is determined (step S204).
When the above equation is established (YES in step S204), the defect determination unit 115 stores that a defect has occurred (has a defect) (step S206). On the other hand, when it is determined that the above equation is not satisfied (step S204—NO), it is determined whether or not the amount of solder protrusion for each pad corresponding to the target component is greater than or equal to a certain level (step S205). . For this purpose, as described above, for each pad position, the area of the solder outside the pad is S_drop>S_drop> mg
Whether or not is satisfied is determined.

  When the above equation is established for at least one of the pads corresponding to the target component (step S205—YES), the amount of solder protruding from the pad exceeds the allowable range. In this case, the defect determination unit 115 stores that a defect has occurred (there is a defect) (step S206).

  On the other hand, when the amount of solder protrusion is less than a certain value and it is determined that the above equation does not hold for any of the pads corresponding to the target component (step S205—NO), or after step S206 described above, The determination unit 115 determines whether or not the defect determination for all components on the printed circuit board 10 has been completed (step S207). Here, when the target part still remains (NO in step S207), the process returns to step S201 to execute defect determination for the next target part. On the other hand, if it is determined that the defect determination for all parts has been completed (step S207—YES), whether or not a “defect” history is stored by executing step S206 so far. Determination is made (step S208). If no “defect” history is stored (step S208—NO), as a result, it is determined that all components are not defective. Therefore, the defect determination unit 115 in this case determines that no defect has occurred (no defect) (step S209). On the other hand, when at least one “defect” history is stored (step S208—YES), the defect determination unit 115 determines that a defect has occurred (defect exists) (step S210).

  Returning to FIG. As shown in FIG. 11, after performing the defect determination process as step S105, the defect determination unit 115 determines whether or not the determination result in step S105 is defective (step S106). When the determination result indicates that there is a defect (YES in step S106), the notification control unit 116 performs control so that audio output or display for notifying that a defect has occurred is performed on the output interface 105 ( Step S107). On the other hand, if the determination result indicates that there is no defect (step S106), the process returns to step S101 without any particular notification, and the subsequent defect inspection of the printed circuit board 10 to be inspected is performed.

(Reference example)
In addition to the processing described above, for example, the solder area change amount difference value α may be a difference value of the change amount after the component mounting process for each solder area on the pad corresponding to one component. . in this case,
α2 = | Sb2-Sa2 |
Can be obtained as follows. In this case, the defect determination unit 115 compares the solder area change amount difference value α2 with a preset threshold th2.
α2 ≧ th2
Whether or not is satisfied is determined. When the formula is satisfied, the defect determination unit 115 determines that a defect has occurred (has a defect), and when it is determined that the expression does not hold, the amount of solder protrusion for each pad corresponding to the target component is constant. It is determined whether or not this is the case.

  In the description so far, for the sake of simplicity of description, two examples of pads corresponding to one component are shown. However, even when the number of pads corresponding to one component is three or more, it is possible to determine a defect based on the difference in the amount of change in the solder area between these pads.

  Further, the above-described defect inspection apparatus has a computer system therein. 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. 8 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 Solder printer 3 Component mounting apparatus 4 Reflow furnace 7 Print board imaging device 8 Component mounting board imaging apparatus 10 Print board 11a, 11b Pad 20a, 20b Solder 30 Parts 31 Electrode 100 Defect inspection apparatus 111 Print board image data Acquisition unit 112 Printed board solder information generation unit 113 Component mounting board image data acquisition unit 114 Component mounting board solder information generation unit 115 Defect determination unit 116 Notification control unit

Claims (4)

The solder area at each pad position on the printed circuit board is determined from the printed circuit board image data obtained by imaging the printed circuit board in which the solder is applied to each pad, which is two soldering locations corresponding to one component, in the solder printing process. A printed circuit board solder information generation unit that generates at least printed circuit board solder information to be stored;
From the component mounting process by the solder coated said printed circuit board component mounting board image data obtained by imaging the mounted the component for each pad, at least the solder area of each pad position in the printed circuit board A component mounting board solder information generation unit for generating component mounting board solder information to be stored;
The solder area acquired from the printed board solder information corresponding to the two pad positions where the determination target component is to be bonded, and the component mounting board solder information corresponding to the two pads where the determination target component is to be bonded based on the solder area obtained from, for the one variation after component mounting step before the solder area of the pad of said two pads, the other variation amount of the component mounting step before and after the solder area of the pad the difference is calculated in correspondence with each pad position to said determination target component is joined, based on a comparison between a preset threshold and the absolute value of the difference of the variation for each pad, which is the calculated A defect determination unit that determines the presence or absence of defects for component mounting of the printed circuit board;
The defect determination unit
When the defect determination result based on the solder area is not defective, it is further determined whether or not there is a defect based on a protruding amount of solder after the component mounting process with respect to a pad to which the determination target component is to be bonded. Defect inspection equipment. A solder printing apparatus for performing a solder printing process for applying solder to a pad of a printed circuit board;
A printed circuit board imaging device that images printed circuit boards in which solder is applied to each pad, which is two soldering locations corresponding to one component by the solder printing device, and generates printed circuit board image data;
A component mounting device for performing a component mounting step of mounting a component on each pad of the printed circuit board to which solder is applied by the solder printing device;
And the component mounting board imaging device for generating component mounting board image data by imaging a printed circuit board on which the component is mounted by the component mounting apparatus,
By melting the solder by heating the printed circuit board on which the component is mounted by the component mounting apparatus, a reflow furnace to reflow step of soldering the the mounted component on the pad,
A defect inspection device,
The defect inspection apparatus includes:
From the printed circuit board image data, a printed circuit board solder information generating unit that generates printed circuit board solder information that stores at least the solder area of each pad position on the printed circuit board;
From the component mounting board image data, a printed board solder information generating unit that generates component mounting board solder information that stores at least solder areas at the respective pad positions on the printed board;
The solder area acquired from the printed board solder information corresponding to the two pad positions where the determination target component is to be bonded, and the component mounting board solder information corresponding to the two pads where the determination target component is to be bonded based on the solder area obtained from, for the one variation after component mounting step before the solder area of the pad of said two pads, the other variation amount of the component mounting step before and after the solder area of the pad the difference is calculated in correspondence with each pad position to said determination target component is joined, based on a comparison between a preset threshold and the absolute value of the difference of the variation for each pad, which is the calculated A defect determination unit that determines the presence or absence of defects for component mounting of the printed circuit board ;
The defect determination unit
When the defect determination result based on the solder area is not defective, it is further determined whether or not there is a defect based on a protruding amount of solder after the component mounting process with respect to a pad to which the determination target component is to be bonded. Component mounting system. The solder area at each pad position on the printed circuit board is determined from the printed circuit board image data obtained by imaging the printed circuit board in which the solder is applied to each pad, which is two soldering locations corresponding to one component, in the solder printing process. A printed circuit board solder information generation step for generating at least printed circuit board solder information to be stored;
From the component mounting process by the solder coated said printed circuit board component mounting board image data obtained by imaging the mounted the component for each pad, at least the solder area of each pad position in the printed circuit board Component mounting board solder information generation step for generating component mounting board solder information to be stored;
The solder area acquired from the printed board solder information corresponding to the two pad positions where the determination target component is to be bonded, and the component mounting board solder information corresponding to the two pads where the determination target component is to be bonded based on the solder area obtained from, for the one variation after component mounting step before the solder area of the pad of said two pads, the other variation amount of the component mounting step before and after the solder area of the pad the difference is calculated in correspondence with each pad position to said determination target component is joined, based on a comparison between a preset threshold and the absolute value of the difference of the variation for each pad, which is the calculated A defect determination step for determining whether or not there is a defect for component mounting on the printed circuit board,
In the defect determination step,
When the defect determination result based on the solder area is not defective, it is further determined whether or not there is a defect based on a protruding amount of solder after the component mounting process with respect to a pad to which the determination target component is to be bonded. Defect inspection method. Computer
The solder area at each pad position on the printed circuit board is determined from the printed circuit board image data obtained by imaging the printed circuit board in which the solder is applied to each pad, which is two soldering locations corresponding to one component, in the solder printing process. Printed circuit board solder information generating means for generating at least stored printed circuit board solder information;
From the component mounting process by the solder coated said printed circuit board component mounting board image data obtained by imaging the mounted the component for each pad, at least the solder area of each pad position in the printed circuit board Component mounting board solder information generating means for generating component mounting board solder information to be stored;
The solder area acquired from the printed board solder information corresponding to the two pad positions where the determination target component is to be bonded, and the component mounting board solder information corresponding to the two pads where the determination target component is to be bonded based on the solder area obtained from, for the one variation after component mounting step before the solder area of the pad of said two pads, the other variation amount of the component mounting step before and after the solder area of the pad the difference is calculated in correspondence with each pad position to said determination target component is joined, based on a comparison between a preset threshold and the absolute value of the difference of the variation for each pad, which is the calculated Function as a defect determination means for determining the presence or absence of defects in the component mounting of the printed circuit board,
In the case where the defect determination result based on the solder area is not defective, the defect determination unit further determines the defect based on the amount of protrusion of the solder after the component mounting process to the pad to which the determination target component is to be bonded. A program that determines the presence or absence.

Images