JP4665878B2 - Electronic component mounting apparatus and electronic component mounting method - Google Patents

Description

  The present invention relates to an electronic component mounting apparatus and an electronic component mounting method for mounting electronic components on a substrate having cream solder printed on electrodes.

  In the surface mounting field of electronic components, when soldering the substrate side electrode and the component side electrode, cream solder is printed on the substrate side electrode in advance, and the component side electrode is positioned on the substrate side electrode via the cream solder. A technique of mounting both electronic parts and joining both electrodes by melting cream solder by reflow is widely used. On the board side, a mounting reference position is set as a reference for positioning when mounting electronic components. When an electronic component is mounted based on this mounting reference position, the component side electrode is accurately positioned on the board side electrode. It comes to be matched. However, when printing defects such as cream solder is printed at a position shifted from the substrate side electrode, if electronic components are mounted based on the mounting reference position, surface tension due to molten solder during reflow As a result, the electronic component may be displaced from the original mounting position, that is, the mounting reference position, or a Manhattan phenomenon may occur in which the electronic component rises due to biased surface tension.

In order to solve such a problem, electronic components are mounted in consideration of a printing position shift of cream solder. Among these, in the apparatus described in Patent Document 1, an electronic component is mounted on the basis of the area center of the printed cream solder. The electronic component mounted in this manner moves on the substrate-side electrode by the self-alignment effect produced by the molten solder, and is automatically corrected to the mounting reference position.
JP 2002-84097 A

  However, in conventional devices that mount electronic components based on the center of area, only planar positional deviation is considered, and three-dimensional printing unevenness is not considered, so self-alignment that is affected by uneven distribution of solder printing amount There may be a case where the position correction by the effect does not function sufficiently.

  Therefore, an object of the present invention is to provide an electronic component mounting apparatus and an electronic component mounting method for mounting an electronic component in consideration of uneven distribution of solder printing amount.

According to one aspect of the present invention, an electronic component mounting apparatus for mounting electronic components on a pair of board-side electrode cream solder is printed, including the cream solder printed protrude from the pair of board-side electrode Calculation means for calculating a planar position of the volume center of the cream solder, and mounting means for mounting the electronic component on the pair of substrate-side electrodes with reference to the planar position of the volume center of the cream solder.

According to a second aspect of the invention, the pair of board-side electrode cream solder is printed an electronic component mounting method of mounting an electronic component, comprising a cream solder printed protrude from the pair of board-side electrode Calculating a planar position of the volume center of the cream solder, and mounting an electronic component on the pair of substrate-side electrodes with reference to the planar position of the volume center of the cream solder.

According to the present invention, the electronic component is mounted on the substrate-side electrode with reference to the plane position of the volume center of the cream solder including the cream solder that is printed out of the pair of substrate-side electrodes. Electronic components can be mounted at the positions considered.

  Embodiments of the present invention will be described with reference to the drawings as appropriate. FIG. 1 is a configuration diagram of an electronic component mounting line according to an embodiment of the present invention, FIG. 2A is a side view showing a state where electronic components are mounted on a substrate, and FIG. FIG. 3A is a side view showing a printed state, FIG. 3A is a plan view showing a state in which cream solder is printed at a normal position on the substrate side electrode, and FIG. 3B is a cream solder at a position shifted from the substrate side electrode. FIG. 3C is a plan view showing a state where an electronic component is mounted on the board-side electrode, and FIG. 4 is a position management flowchart in the electronic component mounting line according to the embodiment of the present invention. .

  First, an electronic component mounting line according to an embodiment of the present invention will be described with reference to FIGS. In FIG. 1, in the electronic component mounting production line, a plurality of devices that perform predetermined processing on a substrate are continuously arranged, and the processing operation in each device is controlled by a line control unit 2 a provided in the management computer 2. It is configured. The board inspection apparatus 3 disposed at the uppermost stream of the line performs a state inspection of a board to be mounted with an electronic component. The printing device 4 disposed downstream of the substrate inspection device 3 performs cream solder printing on the electrodes formed on the substrate. The print inspection device 5 disposed downstream of the printing device 4 inspects the print state including the print position of the cream solder printed on the electrodes. The electronic component mounting device 6 disposed downstream of the print inspection device 5 mounts the electronic component on the electrode on which the cream solder is printed. A mounting position management device 7 disposed downstream of the electronic component mounting device 6 performs position management of the electronic components mounted on the electrodes. The reflow device 8 disposed downstream of the mounting position management device 7 melts the cream solder and joins the electrode of the electronic component and the electrode of the substrate. A mounting position management device 9 disposed downstream of the reflow device 8 performs position management of the electronic component mounted on the electrode. In addition, a substrate discharge mechanism for discharging a defective substrate from the line is provided between the devices constituting the line so that the substrate determined to be defective in the upstream device can be discharged from the line without being transported downstream. It has become.

In FIG. 2A, component-side electrodes 20a and 20b provided on both sides of the electronic component 20 are joined to a pair of substrate-side electrodes 1a and 1b provided on the substrate 1 by cream solders 30a and 30b, respectively. . Thus, an opposite electrode substrate side electrodes 1a and the component side electrode 20a, by the substrate-side electrodes 1b and the component-side electrode 20b is accurately joined, electrical, physically strong bonding is achieved High product quality can be ensured. In FIG. 3A, the mounting reference position a1 is set in advance to a position that is approximately the center of the pair of substrate-side electrodes 1a and 1b. The mounting reference position a1 is the position of the pair of substrate-side electrodes 1a and 1b. It is the substrate side electrode position which shows.

In the printing apparatus 4, the cream solders 30a and 30b are printed at normal positions where they do not protrude from the substrate-side electrodes 1a and 1b (see FIG. 3A). Thus, printing may be performed at a position shifted from each of the substrate-side electrodes 1a and 1b (that is, printed out of the substrate-side electrodes 1a and 1b ) (see FIG. 3B). If the cream solder 30a, 30b is printed at the normal position, the electronic component 20 is mounted on the pair of substrate-side electrodes 1a, 1b with the mounting reference position a1 as a reference, and the opposing electrodes are mounted accurately by subsequent reflow. However, even when the printing is not performed at the normal position, if the mounting reference position a1 is used as a reference, a problem may occur at the time of joining. For example, the surface tension of cream solder 30a, 30b that melts at the time of reflow acts on the electronic component 20, and the electronic component 20 is displaced from the mounting reference position a1 that is the initial mounting position, or a strong surface tension is partially applied. In addition, a bonding failure such as a Manhattan phenomenon in which the electronic component 20 rises is likely to occur.

Therefore, in the electronic component mounting line of the present embodiment, the cream solder 30a including cream solder printed out of the substrate side electrodes 1a and 1b is used instead of the mounting reference position a1 that is the substrate side electrode position. , 30b is mounted on the basis of the printing position of 30b. When mounted in this manner, when the cream solder 30a, 30b melted at the time of reflow wets and spreads on the surface of the substrate side electrodes 1a, 1b, the surface tension is appropriate for the substrate side electrodes 1a, 1b and the component side electrodes 20a, 20b. Therefore, the component-side electrodes 20a and 20b of the electronic component 20 move toward the central portions of the substrate-side electrodes 1a and 1b, respectively (self-alignment effect). Thus, the electronic component 20 is bonded to the pair of substrate-side electrodes 1a and 1b in a state where the position is corrected from the mounting position before reflow to the vicinity of the mounting reference position a1.

  In FIG. 3B, the printing position of the cream solder 30a, 30b, which is a reference when the electronic component 20 is mounted, is the planar position of the volume center b1 of the cream solder 30a, 30b. In addition to the planar positional shift shown in FIG. 3B, the printing defect of the cream solder 30a, 30b includes non-uniformity in the three-dimensional printing amount shown in FIG. The printing amount of 30b is measured by volume, and the plane position of the volume center b1 is set as the mounting reference position of the electronic component 20, so that the position correction function by the self-alignment effect can be sufficiently exhibited.

  The print inspection apparatus 5 includes a volume distribution measuring unit 5a that measures the volume center b1 of the cream solders 30a and 30b. The volume distribution measuring means 5a irradiates each measurement point on the surface of each cream solder 30a, 30b with a laser beam, and from the reflection angle of the laser beam reflected at each measurement point, the triangulation is applied to each measurement point. Measure height. If the heights of the respective measurement points thus measured are integrated in the substrate surface direction, the three-dimensional shapes of the cream solders 30a and 30b can be obtained. Note that the air mixed in the cream solder 30a, 30b or the air entrained when the cream solder 30a, 30b is printed on the substrate-side electrodes 1a, 1b remains in the cream solder 30b and the void 31 is generated. There may be. In this case, since the presence of the void 31 cannot be captured by the laser light reflected on the surface of the cream solder 30b, each measurement point of the cream solder 30b is irradiated with X-rays in the height direction. The amount of cream solder in the height direction of the measurement point is measured, and the volume of cream solder is calculated by integrating the amount of cream solder in the direction of the board surface. Distribution can be obtained.

  The computing unit 2b functions as computing means for calculating the printing position of the cream solder printed on the substrate-side electrode, and the three-dimensional shape or volume distribution of the cream solders 30a, 30b measured by the volume distribution measuring means 5a by the method described above. The volume centers b2 and b3 of the cream solders 30a and 30b are measured, and the volume center b1 of the whole pair of cream solders 30a and 30b is measured. Further, it also functions as a calculation means for calculating the deviation angle θ of the printing position of the cream solders 30a, 30b from the deviation of the planar positions of the volume centers b2, b3.

  The storage unit 2c stores the mounting reference position a1 as mounting reference position data. Further, the volume center b1 and the shift angle θ calculated by the calculation unit 2b are stored as mounting reference position data and mounting reference angle data. The storage unit 2c stores in advance a printing position deviation allowable value that allows the printing position deviation amount of the cream solders 30a and 30b with respect to the pair of substrate-side electrodes 1a and 1b. If the amount of positional deviation is within the allowable value, it is determined that position correction by self-alignment is possible, and the process proceeds to the electronic component mounting process. If the amount exceeds the allowable value, position correction by self-alignment is impossible. It is determined that there is, and the substrate 1 is discharged without being conveyed downstream, and an error warning is notified from the notification unit 10 to the operator.

The electronic component mounting apparatus 6 includes mounting means 6a for mounting the electronic component on the substrate-side electrode with reference to the printing position of the cream solder, and the electronic component mounting device 6 is electronic based on the mounting reference position data and the mounting reference angle data stored in the storage unit 2c. The component 20 is mounted on the pair of substrate-side electrodes 1a and 1b (FIG. 3C
)reference).

  The mounting position management device 7 functions as mounting position management means for managing the mounting position of the electronic component with reference to the printing position of the cream solder, and is based on the mounting reference position data and the mounting reference angle data stored in the storage unit 2c. Thus, the position management of the electronic component 20 mounted on the pair of substrate-side electrodes 1a and 1b is performed. The storage unit 2c stores in advance a mounting position deviation allowable value that allows a mounting position deviation amount with respect to the printing position of the cream solder 30a, 30b of the electronic component 20 mounted on the pair of substrate-side electrodes 1a, 1b. If the amount of positional deviation is within the allowable value, it is determined that the electronic component 20 is mounted at the printing position of the cream solder 30a, 30b, and the process proceeds to the reflow process. On the other hand, if the amount of displacement exceeds the allowable value, the substrate 1 is discharged without being conveyed downstream, and an error warning is notified from the notification unit 10 to the operator.

  The reflow device 8 functions as a joining means for melting the cream solders 30a and 30b by heating and joining the component-side electrodes 20a and 20b of the electronic component 20 and the substrate-side electrodes 1a and 1b.

  The mounting position management device 9 functions as mounting position management means for managing the mounting position of the electronic component with reference to the board-side electrode position, and a pair of board-side electrodes based on the mounting reference position data stored in the storage unit 2c. The position management of the electronic component 20 mounted on 1a, 1b is performed. The storage unit 2c stores in advance a mounting position deviation allowable value that allows a mounting position deviation amount with respect to the mounting reference position a1 of the electronic component 20 mounted on the pair of board-side electrodes 1a and 1b. If the amount of positional deviation is within an allowable value, the electronic component 20 is corrected to the vicinity of the reference mounting position a1 by the self-alignment effect produced by the melted cream solder 30a, 30b. Judged to be properly joined. On the other hand, if the amount of displacement exceeds the allowable value, it is determined that the electronic component 20 is not properly bonded to the pair of substrate-side electrodes 1a and 1b, and the substrate 1 is discharged without being transported downstream. The notification unit 10 notifies the operator of an error warning.

  Next, an electronic component mounting position management method in the electronic component mounting line according to the embodiment of the present invention will be described with reference to the configuration diagram of the electronic component mounting line in FIG. 1 and the position management flowchart in FIG.

  Cream solder is printed on the substrate-side electrode provided on the substrate transferred from the previous process (ST1), and the printed state of the cream solder is inspected (ST2). In this inspection, the printing position of the cream solder printed on the substrate side electrode is calculated (ST3). The printing position deviation amount of the cream solder printing position with respect to the substrate side electrode position printing position is compared with the deviation amount allowable value (ST4), and if the printing position deviation amount is within the allowable value, the cream solder printing position is the mounting reference position. The data and the mounting reference angle data are stored (ST5), and the process proceeds to the next process. On the other hand, if the printing position deviation amount exceeds the allowable value, it is determined that the printing position is defective, and an error warning is notified (ST6). In the next step, an electronic component is mounted on the substrate side electrode based on the mounting reference position data and the mounting reference angle data (ST7). Since a plurality of substrate-side electrodes are provided on the substrate, the print state inspection results for all the substrate-side electrodes are stored as mounting reference position data and mounting reference angle data, and all the results are based on the corresponding data. An electronic component is mounted on the substrate side electrode (ST8).

When the electronic components are mounted on all the substrate-side electrodes, the mounting positions of the electronic components are managed based on the cream solder printing position (ST9). The mounting position deviation amount of the electronic component relative to the printing position of the cream solder is compared with the allowable mounting position deviation amount (ST10). If the mounting position deviation amount is within the allowable value, the process proceeds to the next process, and the allowable value is exceeded. In this case, it is determined that the mounting position is defective, and an error warning is notified (ST11). In the next step, heat treatment by reflow is performed to melt the cream solder and join the electronic component and the substrate side electrode (ST12). After the reflow, the mounting position of the electronic component is managed based on the board-side electrode position (ST13). The mounting position deviation amount of the electronic component with respect to the board-side electrode position is compared with the mounting position deviation allowable value (ST14). If the mounting position deviation amount is within the allowable value, the process proceeds to the next step. It is determined that the component mounting position is defective, and an error warning is notified (ST15).

  As described above, in the electronic component mounting line of the present embodiment, the mounting reference position for managing the mounting position of the electronic component before reflow and the mounting reference position for managing the mounting position of the electronic component after reflow are set. Two different reference positions are set, and position management is performed based on the respective reference positions. Therefore, it is possible to perform optimum position management at each stage in the electronic component mounting line, and by discharging defective substrates more upstream, it is possible to improve yield and product quality.

According to the present invention, the electronic component is mounted on the substrate-side electrode with reference to the plane position of the volume center of the cream solder including the cream solder that is printed out of the pair of substrate-side electrodes. This has the advantage that an electronic component can be mounted at a considered position, and is useful in the field of surface mounting of electronic components.

Configuration diagram of an electronic component mounting line according to an embodiment of the present invention (A) Side view showing a state in which an electronic component is mounted on a substrate (b) Side view showing a state in which cream solder is printed on the substrate side electrode (A) Plan view showing a state in which cream solder is printed on a substrate side electrode at a normal position (b) Plan view showing a state in which cream solder is printed at a position shifted from the substrate side electrode (c) On the substrate side electrode Plan view showing the state where electronic parts are mounted Position management flowchart in the electronic component mounting line of the embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b Substrate side electrode 2b Operation part 6 Electronic component mounting apparatus 6a Mounting means 20 Electronic component 30a, 30b Cream solder b1 Volume center plane position (printing position of cream solder)

Claims (2)

An electronic component mounting apparatus for mounting electronic components on a pair of substrate-side electrodes printed with cream solder,
Calculating means for calculating the plane position of the cream solder volume center including a cream solder printed protrude from the pair of board-side electrode, the pair of substrates and electronic components planar position of the cream solder volume center as a reference An electronic component mounting apparatus comprising: mounting means mounted on the side electrode. An electronic component mounting method for mounting an electronic component on a pair of substrate-side electrodes printed with cream solder,
A step of calculating a planar position of a volume center of the cream solder including the cream solder printed out of the pair of substrate-side electrodes, and an electronic component on the side of the pair of substrates on the basis of the planar position of the volume center of the cream solder. An electronic component mounting method including a step of mounting on an electrode.

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