JP4595857B2 - Electronic component mounting system and electronic component mounting method - Google Patents

Description

The present invention relates to an electronic component mounting system and electronic component mounting method for mounting by solder bonding the electronic component solder bumps are formed on the substrate.

As a form of mounting an electronic component such as a semiconductor element on a circuit board, a method of mounting a semiconductor package in which a semiconductor element is mounted on a resin board to a circuit board via solder bumps is used (for example, Patent Document 1). In this example, the lower surface of the package is imaged and the solder bumps are recognized to automatically detect the bump arrangement and misalignment, and acquire the data for determining the quality of the component and for correcting the position. Yes.
JP 2000-315896 A

  In recent years, with the progress of miniaturization and high functionality of electronic devices, electronic components such as semiconductor packages incorporated in the electronic devices are required to have a high mounting density and are being miniaturized and thinned. Along with this tendency, the resin substrate of the semiconductor package on which the solder bumps are formed also has a characteristic that rigidity is reduced due to thinning, and warpage deformation is easily caused by heating during reflow for solder bonding. For this reason, the solder bumps are lifted due to warping deformation during reflow, and the solder bumps are not normally soldered to the electrodes for connecting the substrate, which tends to cause poor bonding such as poor conduction and insufficient bonding strength.

Accordingly, the present invention aims at providing a beauty electronic component mounting method Oyo electronic component mounting system which can prevent bonding failure in the case of mounting by solder bonding the thin semiconductor package.

The electronic component mounting system according to the present invention is an electronic component mounting system configured to connect a plurality of electronic component mounting apparatuses to each other and mount an electronic component having a plurality of external bonding solder bumps formed on the lower surface thereof on a substrate. A printing apparatus for printing the solder paste on the plurality of electrodes for joining the electronic components formed on the substrate corresponding to the arrangement of the solder bumps, and measuring the planar position and height position of the printed solder paste A printing inspection apparatus, an electronic component mounting apparatus for mounting electronic components on a substrate on which the solder paste is printed by a mounting head, and the solder bumps and the solder paste are heated and melted by heating the substrate on which the electronic components are mounted. The electronic component is soldered to the substrate by the reflow device and the mounting head based on the measurement result of the print inspection device. Control means for controlling a component mounting operation to be mounted on the substrate after printing a strike, and the control means is configured to determine a horizontal position of the mounting head based on a planar position of the solder paste in the component mounting operation. And controlling the descent stop position of the mounting head based on the height position of the solder paste, and in the horizontal position control, the electrodes at the four corners of the outer edge of the plurality of electrodes are controlled. Based on the positional deviation of the printed solder paste, the electronic components are aligned in the horizontal direction, and the height position of each solder paste is measured in advance to determine the height position of the solder paste with the highest height position. The height position of the solder paste printed on the plurality of electrodes can be obtained by using the height position of the solder paste as a reference for the descent stop position in the mounting operation. Location performs control of lowering the stop position of the mounting head so as not squashed highest solder paste the solder bumps.

The electronic component mounting method according to the present invention mounts an electronic component having a plurality of external bonding solder bumps formed on the lower surface on a substrate by an electronic component mounting system configured by connecting a plurality of electronic component mounting apparatuses. An electronic component mounting method, a printing step of printing a solder paste on an electrode for joining electronic components formed on the substrate, a printing inspection step of measuring a planar position and a height position of the printed solder paste, A component mounting step of mounting an electronic component on a substrate on which the solder paste is printed by a mounting head; and heating and melting the solder bump and the solder paste by heating the substrate on which the electronic component is mounted. A reflow process for soldering to the board, and mounting the electronic component on the board after the solder paste is printed by the mounting head. Te, performs horizontal position control of the mounting head based on the plane position of the solder paste to control the descent stop position of the mounting head based on the height position of the solder paste, the position of the horizontal direction In the control, the electronic components are aligned in the horizontal direction based on the misalignment of the solder paste printed on the electrodes at the four corners of the outer edge of the plurality of electrodes, and the height position of each solder paste is set in advance. Measure and grasp the height position of the solder paste with the highest height position, and use this solder paste height position as a reference for the descent stop position in the mounting operation. The lowering stop position of the mounting head is controlled so that the solder bump does not crush the solder paste having the highest height among the solder pastes .

  According to the present invention, a component mounting is performed in which a planar position and a height position of a solder paste are measured in advance for a substrate after printing the solder paste, and an electronic component is mounted on the substrate after the solder paste is printed by the mounting head. In operation, the horizontal position of the mounting head is controlled based on the planar position of the solder paste, and the lowering stop position of the mounting head is controlled based on the height position of the solder paste, so that warpage deformation is likely to occur. It is possible to prevent a bonding failure when a thin semiconductor package is mounted by solder bonding.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an electronic component mounting system according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a screen printing apparatus according to an embodiment of the present invention, and FIG. FIG. 4 is a block diagram showing a configuration of an electronic component mounting apparatus according to an embodiment of the present invention, and FIG. 5 is an electronic component mounting according to an embodiment of the present invention. FIG. 6 is a block diagram of a control system of the system, FIG. 6 is a flowchart showing an electronic component mounting method according to an embodiment of the present invention, and FIG. FIG. 8 is a process explanatory diagram of an electronic component mounting method according to an embodiment of the present invention, and FIGS. 9 and 10 are explanatory diagrams of position measurement of solder paste and solder bumps in the electronic component mounting method according to an embodiment of the present invention. FIG. 11 is an explanatory view of the solder bump positioning and solder bonding process in the electronic component mounting method according to the embodiment of the present invention.

  First, an electronic component mounting system will be described with reference to FIG. In FIG. 1, the electronic component mounting system is an electronic component mounting line configured by connecting the printing device M1, the printing inspection device M2, the electronic component mounting device M3, and the reflow device M4, all of which are devices for mounting electronic components. 1 is connected by a communication network 2 and the whole is controlled by a management computer 3. In the present embodiment, an electronic component having a plurality of external connection solder bumps formed on the lower surface is mounted on the substrate by solder bonding using the plurality of electronic component mounting apparatuses to manufacture a mounting substrate.

  The printing apparatus M1 screen-prints a solder paste for joining an electronic component on an electrode formed on the substrate to be mounted corresponding to the arrangement of the solder bumps of the electronic component. The print inspection apparatus M2 inspects the printing state by recognizing the planar position of the printed solder paste by imaging the printed board and performing three-dimensional measurement on the printed board. Thus, the height position of the printed solder paste is measured. The electronic component mounting apparatus M3 mounts electronic components on a substrate on which a solder paste is printed by using a mounting head. The reflow device M4 heats and melts the solder bumps and the solder paste by heating the substrate on which the electronic component is mounted, and solder-bonds the electronic component to the substrate.

  Next, the configuration of the printing apparatus M1, the printing inspection apparatus M2, and the electronic component mounting apparatus M3 will be described. First, the configuration of the printing apparatus M2 will be described with reference to FIG. In FIG. 2, a substrate holder 11 is disposed on the positioning table 10. The substrate holding unit 11 holds the substrate 4 sandwiched from both sides by the clamper 11a. A mask plate 12 is disposed above the substrate holding part 11, and a pattern hole (not shown) corresponding to a printing portion of the substrate 4 is provided in the mask plate 12. By driving the positioning table 10 by the table driving unit 14, the substrate 4 moves relative to the mask plate 12 in the horizontal direction and the vertical direction.

  A squeegee unit 13 is disposed above the mask plate 12. The squeegee unit 13 includes an elevating and pressing mechanism 13b that elevates and lowers the squeegee 13c relative to the mask plate 12 and presses the mask plate 12 with a predetermined pressing force (printing pressure), and a squeegee moving mechanism 13a that horizontally moves the squeegee 13c. The elevation pressing mechanism 13 b and the squeegee moving mechanism 13 a are driven by the squeegee driving unit 15. In a state where the substrate 4 is in contact with the lower surface of the mask plate 12, the solder paste 5 is moved to a pattern (not shown) by horizontally moving the squeegee 13c at a predetermined speed along the surface of the mask plate 12 to which the solder paste 5 is supplied. It prints on the upper surface of the electrode 4a formed in the board | substrate 4 through the hole (refer Fig.7 (a)).

  This printing operation is performed by controlling the table driving unit 14 and the squeegee driving unit 15 by the printing control unit 17. In this control, the operation of the squeegee 13 c and the alignment between the substrate 4 and the mask plate 12 are controlled based on the print data stored in the print data storage unit 16. The display unit 19 displays various types of index data indicating the operating state of the printing apparatus and an abnormality notification indicating an abnormality in the printing operation state. The communication unit 18 exchanges data with the management computer 3 and other devices constituting the electronic component mounting line 1 via the communication network 2.

  Next, the print inspection apparatus M2 will be described with reference to FIG. In FIG. 3, the substrate 4 is held on the transport rail 20 in a state where both ends are clamped by the clamp member 20a. By driving the substrate conveyance positioning unit 21, the conveyance rail 20 conveys and positions the substrate 4 to a position for inspection and measurement described below.

  A height measuring device 22 and a substrate recognition camera 24 are disposed above the substrate 4 held on the transport rail 20. The height measuring instrument 22 has a function of precisely measuring the distance to the measurement target, and the height measuring instrument 22 measures the solder paste 5 set on the electrode 4a of the substrate 4 to measure the height of the measurement data. By processing with the measurement part 23, the height position of the solder paste 5 printed on each electrode 4a can be calculated | required. In addition, the image recognition unit 25 recognizes the imaging result obtained by the board recognition camera 24 to detect the planar position and the print area of the solder paste 5 to determine whether the solder paste 5 is normally printed. Can be inspected. The height measuring device 22 and the substrate recognition camera 24 can be moved in a horizontal plane by moving means, respectively, and an arbitrary position of the substrate 4 can be set as a height measurement object and an inspection object.

  The data indicating the height position of the solder paste 5 and the print state inspection result acquired by the height measurement are processed by the inspection / measurement processing unit 26. Thereby, the solder plane position data and the solder height position data respectively indicating the plane position and the height position of the solder paste 5 printed on the board, together with the pass / fail judgment result about the printed state on the individual board 4 after printing, are obtained. Is output. These output data are transferred to the management computer 3 and other devices via the communication unit 28 and the communication network 2. The inspection / measurement control unit 29 controls the inspection / measurement operation by controlling the substrate transport positioning unit 21, the height measuring device 22, and the substrate recognition camera 24.

  Next, the configuration of the electronic component mounting apparatus will be described with reference to FIG. In FIG. 4, the substrate 4 is held on the transport rail 30 in a state where both ends are clamped by a clamp member 30a. The clamp member 30a that clamps the substrate 4 in the transport rail 30 has the same structure as the transport rail 20 and the clamp member 20a in the print inspection apparatus M2, and holds the substrate 4 in the same clamp state as in the print inspection. By driving the substrate conveyance positioning unit 31, the conveyance rail 30 conveys and positions the substrate 4 on which the solder paste 5 is printed on the electrode 4a in the previous process to a component mounting position by a mounting head 32 described below. The substrate conveyance positioning unit 31 and the conveyance rail 30 are substrate positioning units that position the substrate 4 on which the solder paste 5 is printed on the electrode 4a in the previous process.

  A mounting head 32 that is moved by a head drive mechanism (not shown) is disposed above the substrate 4 held on the transport rail 30. The mounting head 32 includes a nozzle 32a that sucks an electronic component, and the mounting head 32 picks up and holds the electronic component from the component supply unit (not shown) by the nozzle 32a. Then, the electronic component held by the nozzle 32 a is mounted on the substrate 4 by moving the mounting head 32 onto the substrate 4 and lowering it with respect to the substrate 4. The mounting head 32 and a head driving mechanism (not shown) constitute a component mounting mechanism for mounting electronic components on the substrate 4 on which the solder paste 5 is printed.

  A component recognition camera 40 is disposed on the movement path along which the mounting head 32 moves onto the substrate 4. The mounting head 32 moves above the component recognition camera 40 with the electronic component 34 held by the nozzle 32 a. Thus, an image of the electronic component 34 held by the mounting head 32 is acquired (see FIG. 10A). The image recognition unit 41 recognizes the image data, whereby the electronic component 34 is recognized. The position of the solder bump 34 a formed on the lower surface of the electronic component 34 is detected by the recognition of the electronic component 34. The component recognition camera 40 and the image recognition unit 41 are component recognition means provided in the electronic component mounting apparatus M3.

  In the mounting operation, the substrate transport positioning unit 31 and the mounting head driving unit 33 are controlled by the mounting control unit 37 based on the mounting data stored in the mounting data storage unit 36, that is, the mounting coordinates of the electronic component on the substrate 4. Thus, the electronic component mounting position on the substrate 4 by the mounting head 32 can be controlled. At this time, the mounting condition data stored in the mounting condition storage unit 35, that is, the control parameter for controlling the details of the operation pattern when the nozzle 32a is driven up and down by the mounting head 32 in the mounting operation, is added to the mounting head 32. By controlling, a more precise mounting operation can be performed as described later.

  Here, as a control parameter, a horizontal position correction parameter when the electronic component is aligned with the substrate 4 by the mounting head 32 and a lowering when the electronic component is landed on the substrate 4 by lowering the mounting head 32. The parameter indicating the stop position is updated for each electronic component based on the data indicating the planar position and the height position of the solder paste 5 measured by the printing inspection apparatus M2. In the configuration described above, the mounting control unit 37 uses the mounting head 32 to place the electronic component on the solder paste 5 based on the result of measuring the planar position and height position of the solder paste printed in the previous process by the printing inspection apparatus M2. This is a control means for controlling the component mounting operation to be mounted on the printed circuit board 4.

  The display unit 39 displays index data indicating various operating states of the electronic component mounting apparatus M3 and an abnormality notification indicating an abnormality in the mounting operation state. The communication unit 38 exchanges data with the management computer 3 and other devices constituting the electronic component mounting line 1 via the communication network 2.

Next, the configuration of the control system of the electronic component mounting system will be described with reference to FIG. Here, a data transfer function for the purpose of updating control parameters in the electronic component mounting process will be described. In FIG. 5, the overall control unit 50 has a data transfer function within the control processing range executed by the management computer 3, and is transferred from each device constituting the electronic component mounting line via the communication network 2. Data is received and output as parameter update data to each device via the communication network 2 based on a predetermined processing algorithm.

  That is, the inspection / measurement processing unit 26 provided in the print inspection apparatus M2 illustrated in FIG. 3 is connected to the communication network 2 via the communication unit 28. Each unit (see FIGS. 2 and 4) provided in the printing apparatus M1 and the electronic component mounting apparatus M3 is connected to the communication network 2 via the communication units 18 and 38, respectively. Thereby, feedback processing for correcting / updating the control parameters of the upstream device based on the data extracted in the inspection / measurement process in the printing inspection device M2, and feedforward processing for correcting and updating the control parameters of the downstream device are performed. The configuration is possible at any time during operation of each device. Note that the control unit of each device may be provided with a data transfer control function without providing the management computer 3.

  In the configuration of the electronic component mounting system described above, a print inspection device M2 provided independently between the printing device M1 and the electronic component mounting device M3 is sandwiched. May be attached to the printing apparatus M1 or the electronic component mounting apparatus M3. That is, the height measuring device 22 and the substrate recognition camera 24 are arranged so that measurement and imaging can be performed on the printed substrate 4 in the printing apparatus M1, and the height measurement unit 23, the substrate recognition camera 24, and the image recognition unit are arranged. 25. The functions of the inspection / measurement processing unit 26, the inspection data storage unit 27, and the inspection / measurement control unit 28 are added to the control function of the printing inspection apparatus M2. Thereby, the same inspection and measurement can be performed inside the printing apparatus M1 for the substrate 4 after printing. The same applies to the case where these functions are attached to the electronic component mounting apparatus M3. In this case, the same inspection and measurement are performed on the substrate 4 directly carried from the printing apparatus M1 inside the electronic component mounting apparatus M3. Is executed prior to the component mounting operation.

  Next, an electronic component mounting method for mounting an electronic component 34 having a plurality of solder bumps 34a formed on the lower surface on the substrate 4 by the electronic component mounting system shown in the present embodiment will be described with reference to the flowchart of FIG. Will be described with reference to FIG. First, as shown in FIG. 7A, the printing apparatus M1 prints the solder paste 5 on the electrode 4a of the substrate 4 (printing process) (ST1). Next, the printed board 4 is carried into the print inspection apparatus M2, where the planar position and height position of the solder paste 5 printed on the electrode 4a are determined by the board recognition camera 24, as shown in FIG. Measurement is performed by the height measuring instrument 22 (printing inspection process) (ST2).

  That is, as shown in FIG. 9A, images of a plurality of solder pastes 5 printed on the substrate 4 at positions corresponding to the arrangement of the solder bumps on the electronic component are picked up by the substrate recognition camera 24. By performing the recognition processing, the planar position of each solder paste 5 is recognized. In the present embodiment, the position (indicated by ＊) of the solder paste 5 * located at the four corners of the diagonal among the plurality of solder pastes 5 is detected, and the overall position of the plurality of solder pastes 5 is detected. To represent.

As will be described later, in a semiconductor package having a structure in which a semiconductor element is mounted on a thin resin substrate, the solder bump located at the outer edge becomes the most critical presence in solder bonding with the electrode 4a of the substrate 4 due to warpage deformation. It is known. That is, the semiconductor package may already have warpage deformation due to a thermal history in the manufacturing process, and further, the outer edge portion warps upward by heating in the reflow process after being mounted on the substrate. The closer the solder bump located in the part, the higher the gap from the electrode on the substrate, and there is a tendency to create a gap between the solder paste 5 printed on the electrode. In addition to the presence of such a gap, when the solder bump and the solder paste 5 are also displaced in the horizontal direction, the solder in which the solder bump 5 is melted and the solder in which the solder paste 5 is melted in the reflow process The probability of not touching each other increases synergistically.

  For this reason, when the electronic component to be mounted is a semiconductor package that is likely to be warped and deformed, the horizontal displacement between the solder bump 5 and the solder paste 5 at the outer edge where the soldering condition is most critical. It is required to keep it as small as possible. For this reason, in this embodiment, the positions of the solder pastes 5 * at the four corners are detected, and the component mounting positions that minimize the positional deviation between the solder pastes 5 * and the solder bumps are obtained. ing.

  Further, in the three-dimensional measurement by the height measuring device 22, the height position of each solder paste 5 on the substrate 4 is measured, and as shown in FIG. 9B, the height of the solder paste 5 located in each cross section. The position is determined individually. In the present embodiment, the solder paste 5a giving the highest height position is detected from the plurality of height measurement results, and the electronic component 34 is landed on the solder paste 5 at the height position of the solder paste 5a. Used as the reference height position.

  In other words, the substrate 4 on which the electronic component is mounted may be warped and deformed in the vertical direction when the component is mounted due to the deformation generated in the manufacturing stage. In such a case, the solder paste 5 printed on the electrode 4a located on the convex portion of the warp deformation is at a higher position than the other portions, so that the solder paste 5 at such a high position is soldered in the mounting operation. Bumps land first. Then, if the mounting operation according to the design data given in advance is executed while ignoring the variation in the height direction, the solder bumps are excessively pushed into the solder paste 5 at a high position, and the printed solder paste 5 is As a result, it is crushed by the solder bumps and protrudes in the horizontal direction.

  The protrusion of the solder paste 5 between the solder bumps is a problem that must be avoided because it causes an electrical short circuit between the electrodes in fine pitch mounting where the pitch between the bumps is small. Therefore, in the present embodiment, the height position of each solder paste 5 is measured in advance, the height position of the solder paste 5a having the highest height position is grasped, and the height position of the solder paste 5a is determined. Is used as a reference for the descent stop position in the mounting operation, so that the solder paste is not crushed. Here, as a reference for the descent stop position, the height position at which the lower end of the solder bump 34a sinks to the upper surface of the solder paste 5a by a predetermined pushing amount Δh (see FIG. 11A) is the lower end of the nozzle 32a. Is defined as the descent stop position HL.

  Thereafter, the measurement result obtained as described above is transmitted to the electronic component mounting apparatus M3 (ST3), and the substrate 4 is carried into the electronic component mounting apparatus M3. In the electronic component mounting apparatus M3, the position of the solder bump 34a on the lower surface of the electronic component 34 is recognized during the transfer of the electronic component to the substrate 4 by the mounting head 32 (ST4). In the present embodiment, similarly to the planar position of the solder paste 5 on the substrate 4, as shown in FIG. 10A, among the plurality of solder bumps 34a on the lower surface of the electronic component 34, the diagonal four corners The position (indicated by x) of the solder bump 34a * located at is detected. Then, the mounting control unit 37 sets the control parameters of the mounting operation stored in the mounting condition storage unit 35 based on the position recognition result of the solder bumps 34a thus obtained and the position measurement result of the solder paste 5. Update processing is performed (ST5).

First, as shown in FIG. 10B, when the positions of the four solder pastes 5 * located at the four corners and the positions of the four solder bumps 34a * are overlapped, positional deviations at the respective corners are shown. A superposition state in which d1, d2, d3, and d4 are substantially equal is obtained by coordinate calculation. The position of the electronic component 34 in which such a relationship is realized in the horizontal relative position between the substrate 4 and the electronic component 34 becomes a post-correction mounting point in the actual mounting operation.

  That is, a positional deviation amount ΔMp (two-dimensional positional deviation amount in consideration of the direction) between the component center of the electronic component 34 and the normal mounting point Mp given by the design mounting coordinate data in the state shown in FIG. Is obtained as a control parameter for horizontal alignment of the electronic component. In the actual component mounting operation, the electronic component 34 is mounted by the mounting head 32 with the target mounting point Mp * corrected by correcting the mounting point Mp indicated in the mounting data stored in the mounting data storage unit 36 by ΔMp. The

  The control parameters for the lowered position control are updated together with the control parameters for the horizontal alignment. That is, based on the measurement data transmitted from the print inspection apparatus M2, as described above, the mounting control unit 37 sets the lowering stop position HL at the lower end of the nozzle 32a according to the height position of the solder paste 5a in the electronic component. Calculate and update as a new control parameter. That is, the mounting control unit 37 serving as a control unit performs horizontal position control of the mounting head 32 based on the planar position of the solder paste 5 in the component mounting operation, and based on the height position of the solder paste 5. The descent stop position of the mounting head 32 is controlled.

  In the horizontal position control of the mounting head 32, the horizontal alignment of the electronic component 34 is performed based on the positional deviation of the solder paste 5 * printed on the electrodes at the four corners of the outer edge of the plurality of electrodes 4a. And adopting a form in which the lowering stop position of the mounting head 32 is controlled so that the solder bump 34a does not crush the solder paste 5a having the highest height among the solder pastes 5 printed on the plurality of electrodes 4a. ing.

  In the present embodiment, the electronic component mounting apparatus M3 is provided with the positions of the solder bumps 34a * corresponding to the electrodes at the four corners of the outer edge of the electronic component 34 when the electronic component is aligned in the horizontal direction. Recognized by the component recognition means, and this recognition result is taken into account. However, when the position accuracy of the solder bump is ensured depending on the type of the electronic component, the solder bump at the four corners is used. It is not necessary to identify and detect. In such a case, the electronic component can be aligned based on the average position of the solder bumps.

  Next, the mounting operation is executed with the updated control parameters (ST6). With reference to FIG. 11, the component mounting operation executed using the control parameter updated in this way and the behavior in the reflow process after mounting the component will be described. The substrate 4 is warped and the height of the solder paste 5 printed on the electrode 4a varies. Here, the solder paste 5 printed on the electrode 4a located at the approximate center is the most. This corresponds to the solder paste 5a having a high height. In FIG. 11, only the solder bumps 34a corresponding to the solder paste 5a and the solder bumps 34a * corresponding to the solder paste 5 * located on the opposite edge of the outer edge are illustrated, and other solder pastes 5 and solder bumps 34a are shown. Illustration is omitted.

  FIG. 11A shows a state in which the electronic component 34 sucked and held by the nozzle 32a is lowered with respect to the substrate 4, and the lower end portion of the nozzle 32a is stopped at the lowering stop position HL which is a control parameter. At this time, since the solder bump 34a stops at a position where it sinks by Δh with respect to the upper surface of the solder paste 5a, the solder paste 5 is not crushed and spread around by excessive pressing. Then, the solder bump 34a corresponding to the solder paste 5 having a low height position does not contact the solder paste 5 and maintains some gap.

The alignment in the horizontal direction is performed so that the state shown in FIG. As a result, the relative positional deviation between the solder paste 5 * and the solder bump 34a * caused by the printing position accuracy and the bump formation accuracy of the solder paste 5 becomes substantially uniform for each diagonal position, and either outer edge. In this portion, misalignment between the solder paste 5 and the solder bump 34a does not occur unevenly.

  Thereafter, the substrate 4 after mounting the electronic component is carried into the reflow apparatus M4 (ST7). FIGS. 11B and 11C show a process in which the electronic component 34 is soldered to the electrode 4a via the solder paste 5 by heating the substrate 4 after mounting the component with the reflow apparatus M4. When the electronic component 34 is heated together with the substrate 4, the solder paste 5 on the electrode 4 a is softened and the solder bump 34 a sinks into the solder paste 5, and the height of the electronic component 34 on the substrate 4 decreases with heating. . At this time, since the electronic component 34 is thermally deformed and exhibits a deformation behavior in which the outer edge side warps upward, the solder bumps 34a * located on the outer edge portion are displaced upward together with the electronic component 34, and correspondingly. The gap between the solder paste 5 * increases.

  Thereafter, the heating is further continued to melt the solder bump 34a and the solder in the solder paste 5, and the electronic component 34 is soldered to the electrode 4a of the substrate 4 (reflow process) (ST8). In this solder joint, the solder is melted in the solder paste 5a in which the solder bumps 34a are already sinking, so that the electronic component 34 sinks due to its own weight, and the molten solder wets and spreads on the surface of the electrode 4a. Due to the action of the surface tension, the electronic component 34 is attracted to the substrate 4 and lowered as a whole.

  As a result, the solder bump 34a * that is initially lifted also comes into contact with the solder paste 5 * due to the lowering of the electronic component 34, and the solder bump 34a * is connected to the electrode 4a via the solder component in the solder paste 5 *. And soldered together. At this time, the relative displacement in the horizontal direction between the solder bump 34a * and the solder paste 5 * is not biased and does not exceed a predetermined range determined according to the accuracy control level. The probability that a bonding failure will occur is extremely small.

  As described above, in the present embodiment, the planar position and height position of the solder paste 5 are measured in advance for the printed circuit board 4 of the solder paste 5, and the electronic component 34 is mounted by the mounting head 32. In the component mounting operation for mounting on the substrate 4 after the solder paste 5 is printed, the horizontal position control of the mounting head 32 is performed based on the planar position of the solder paste 5 and the mounting is performed based on the height position of the solder paste 5. The descent stop position of the head 32 is controlled. Thereby, it is possible to prevent a bonding failure when a thin semiconductor package which is likely to be warped is mounted by solder bonding.

  The electronic component mounting system and the electronic component mounting method according to the present invention have an effect of preventing a bonding failure when a thin semiconductor package that easily warps and deforms is mounted by solder bonding. The present invention can be used in the field of manufacturing a mounting board by mounting by solder bonding.

The block diagram which shows the structure of the electronic component mounting system of one embodiment of this invention The block diagram which shows the structure of the screen printing apparatus of one embodiment of this invention 1 is a block diagram showing a configuration of a print inspection apparatus according to an embodiment of the present invention. The block diagram which shows the structure of the electronic component mounting apparatus of one embodiment of this invention The block diagram of the control system of the electronic component mounting system of one embodiment of this invention The flowchart which shows the electronic component mounting method of one embodiment of this invention Process explanatory drawing of the electronic component mounting method of one embodiment of this invention Process explanatory drawing of the electronic component mounting method of one embodiment of this invention Explanatory drawing of position measurement of solder paste and solder bump in the electronic component mounting method of one embodiment of the present invention Explanatory drawing of position measurement of solder paste and solder bump in the electronic component mounting method of one embodiment of the present invention Explanatory drawing of the solder bump alignment and solder bonding process in the electronic component mounting method of one embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic component mounting line 4 Board | substrate 4a Electrode 5 Solder paste 22 Height measuring device 24 Board | substrate recognition camera 32 Mounting head 34 Electronic component 34a Solder bump 40 Component recognition camera M1 Printing apparatus M2 Printing inspection apparatus M3 Electronic component mounting apparatus M4 Reflow apparatus

Claims (4)

An electronic component mounting system configured to connect a plurality of electronic component mounting apparatuses and mount an electronic component having a plurality of solder bumps for external bonding formed on a lower surface on a substrate,
A printing apparatus that prints a solder paste on a plurality of electrodes for joining electronic components formed on the substrate corresponding to the arrangement of the solder bumps, and a print inspection that measures the planar position and height position of the printed solder paste An apparatus, an electronic component mounting apparatus for mounting an electronic component on a substrate on which the solder paste is printed by a mounting head, and the solder bump and the solder paste are heated and melted by heating the substrate on which the electronic component is mounted. A reflow device that solder-bonds the electronic component to the substrate, and a control unit that controls a component mounting operation for mounting the electronic component on the substrate after the solder paste is printed by the mounting head based on the measurement result of the printing inspection device. Prepared,
The control means performs a horizontal position control of the mounting head based on a planar position of the solder paste in the component mounting operation, and a lowering stop position of the mounting head based on a height position of the solder paste. controls,
In the horizontal position control, the electronic components are aligned in the horizontal direction based on the positional deviation of the solder paste printed on the electrodes at the four corners of the outer edge of the plurality of electrodes, By measuring the height position of the solder paste, grasping the height position of the solder paste having the highest height position, and using the height position of the solder paste as a reference for the descent stop position in the mounting operation. An electronic component mounting system that controls the descent stop position of the mounting head so that the solder bump does not crush the solder paste having the highest height position among the solder pastes printed on the electrodes . In the electronic component, the positions of the solder bumps corresponding to the electrodes at the four corners of the outer edge are recognized by the component recognition means provided in the electronic component mounting apparatus, and the level of the electronic component is taken into account by taking this recognition result into consideration. electronic component mounting system according to claim 1, wherein the aligning direction. A plurality of electronic components the electronic component mounting system for mounting equipment is configured by connecting an electronic component in which a plurality of solder bumps for external bonding to the lower surface is formed by an electronic component mounting method that implements the substrate,
Printing process for printing solder paste on electrodes for joining electronic components formed on the substrate, printing inspection process for measuring the planar position and height position of the printed solder paste, and printing the solder paste by a mounting head A component mounting step of mounting an electronic component on the substrate, and a reflow step of heating and melting the solder bump and the solder paste by heating the substrate on which the electronic component is mounted and soldering the electronic component to the substrate. Including
In the component mounting operation in which the electronic component is mounted on the substrate after the solder paste is printed by the mounting head, the mounting head performs horizontal position control based on the planar position of the solder paste, and the height of the solder paste Control the descent stop position of the mounting head based on the position ;
In the horizontal position control, the electronic components are aligned in the horizontal direction based on the positional deviation of the solder paste printed on the electrodes at the four corners of the outer edge of the plurality of electrodes, By measuring the height position of the solder paste, grasping the height position of the solder paste having the highest height position, and using the height position of the solder paste as a reference for the descent stop position in the mounting operation. An electronic component mounting method comprising: controlling the descent stop position of the mounting head so that the solder bump does not crush the solder paste having the highest height position among the solder pastes printed on the electrodes . In the electronic component, the positions of the solder bumps corresponding to the electrodes at the four corners of the outer edge are recognized by the component recognition means provided in the electronic component mounting apparatus, and the level of the electronic component is taken into account by taking this recognition result into consideration. 4. The electronic component mounting method according to claim 3, wherein alignment of directions is performed.

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