JP5338847B2 - Screen printing apparatus and screen printing method in electronic component mounting system - Google Patents

Description

  The present invention relates to a screen printing apparatus and a screen printing method in an electronic component mounting system for manufacturing a mounting substrate by mounting electronic components on a substrate.

  An electronic component mounting system that manufactures a mounting substrate by mounting electronic components on a substrate by solder bonding is a printing device that prints a solder paste for component bonding on a substrate electrode, and the electronic component is mounted on a substrate on which the solder paste is printed A plurality of electronic component mounting devices, such as an electronic component mounting device that performs such processing and a reflow device that melts and solidifies solder paste, are connected. In such an electronic component mounting system, with the recent miniaturization of electronic components and the increase in mounting density, the positional accuracy required when mounting electronic components on a substrate has also been advanced. That is, it is required to secure the printing position accuracy when the solder paste is printed on the electrode position in the printing apparatus and the mounting position accuracy when mounting the electronic component on the solder paste on the printed board at a high level. For this reason, as a printing apparatus, a configuration for the purpose of accurately aligning the substrate and the screen mask is known (see Patent Document 1).

  In the prior art example shown in Patent Document 1, a recognition device having a configuration in which two recognition means are arranged in parallel in the horizontal direction is positioned between the screen mask and the substrate, thereby simultaneously recognizing the substrate and the screen mask. An example is shown in which the vertical movement stroke at the time of mask alignment is reduced to minimize the displacement error generated during the alignment operation.

JP 2007-130910 A

  However, in the prior art including the above-described prior art examples, the following problems have occurred when aligning the substrate and the screen mask. In other words, conventionally, as the position reference when aligning the substrate and the screen mask, the center of the substrate is made to coincide with the center position of the screen mask. When expansion / contraction due to deformation or the like occurs, the pattern of the screen mask that hardly undergoes expansion / contraction deformation and the electrode of the substrate do not coincide with each other in the peripheral region of the substrate, resulting in misalignment. When screen printing is executed in such a state, the solder paste is printed on the substrate while being displaced from the electrodes.

  By the way, on the board that is the target of component mounting, a plurality of recognition marks are provided in association with the positions of the component mounting points, and in the component mounting process, based on the recognition result obtained by imaging and recognizing these recognition marks, Mounting position data serving as a target position when electronic components are mounted on each component mounting point is calculated. Since the position of the recognition mark is similarly displaced when the substrate is expanded and contracted as described above, the mounting position data calculated based on the recognition result of the recognition mark is the displacement accompanying the expansion and contraction of the substrate. The minutes are corrected.

  Therefore, the position of the solder paste printed by the screen mask pattern does not coincide with the corrected component mounting position corrected by the recognition mark recognition, and the electronic component after mounting is out of position from the solder paste. Become. If the amount of misregistration generated in this way becomes excessive, a joining failure such as “part standing” or “bridge” occurs due to an imbalance of the surface tension of the molten solder in the reflow process. As described above, the conventional technique has a problem that due to the expansion and contraction deformation of the substrate, the position of the solder paste printed on the substrate and the component mounting position are displaced, resulting in a bonding failure.

  Accordingly, the present invention provides screen printing in an electronic component mounting system that can reduce the positional deviation between the position of the solder paste printed on the substrate and the component mounting position, even when the substrate is subject to expansion / contraction deformation. An object is to provide an apparatus and a screen printing method.

  A screen printing apparatus according to the present invention is configured by connecting a plurality of electronic component mounting apparatuses, and mounting electronic components on a substrate to manufacture a mounting substrate. In the electronic component mounting system, electronic components are mounted by a mounting head from a component supply unit. A screen printing apparatus in an electronic component mounting system that is arranged on the upstream side of an electronic component mounting device that is picked up and mounted on the substrate and prints a paste for component bonding on an electrode formed on the substrate, wherein the paste is A screen printing mechanism for printing a paste on the substrate positioned and held by the substrate positioning portion through a pattern hole formed in the screen mask by sliding a squeegee on the supplied screen mask; and the screen mask The mask recognition mark formed on the substrate and the substrate recognition mark formed on the substrate A mark recognizing unit for recognizing, an alignment control unit for aligning the substrate with respect to the screen mask by controlling the substrate positioning unit based on a recognition result of the mark recognizing unit, and alignment of the substrate Printing position data indicating the positional relationship between the pattern hole array and the mask recognition mark, and the mounting position indicating the positional relationship between the position of the component mounting point on the substrate and the substrate recognition mark. A data storage unit that stores data for each board type, and the alignment control unit prints the paste on the board according to a predetermined position correction algorithm based on the recognition result of the board recognition mark and the mounting position data. A plurality of print target positions to be obtained are obtained, and then the recognition result of the mask recognition mark is determined. The plurality of pattern holes in said plurality of print target position degree of match approximately to align the substrate such that the maximum under the predetermined condition on the basis of the fine the printing position data.

  The screen printing method of the present invention is an electronic component mounting system configured to connect a plurality of electronic component mounting apparatuses and mount the electronic component on a substrate to manufacture the mounting substrate. A screen printing method in an electronic component mounting system for printing a component bonding paste on an electrode formed on the substrate prior to mounting an electronic component to be picked up and mounted on the substrate, the screen being supplied with the paste Formed on the screen mask prior to the screen printing step of printing paste on the substrate positioned and held by the substrate positioning portion through the pattern holes formed in the screen mask by sliding the squeegee on the mask Mask recognition marks and substrate recognition marks formed on the substrate are recognized. Performing a mark recognition step, and an alignment control step of aligning the substrate with respect to the screen mask by controlling the substrate positioning unit based on the recognition result obtained in the mark recognition step, In the alignment control step, in the board according to a predetermined position correction algorithm based on the recognition result of the board recognition mark and the mounting position data indicating the positional relationship between the position of the component mounting point on the board and the board recognition mark. A plurality of print target positions where the paste is to be printed are obtained, and then a plurality of print target positions are printed based on the recognition result of the mask recognition mark and print position data indicating the positional relationship between the pattern hole array and the mask recognition mark. The degree to which the pattern holes approximately match is maximized under a predetermined condition Uni aligning the substrate.

  According to the present invention, the paste should be printed on the substrate based on the recognition result and the mounting position data obtained in the first mark recognition step for recognizing the mask recognition mark and the substrate recognition mark prior to the screen printing step. A plurality of print target positions are obtained, and then the degree to which the plurality of pattern holes approximately match the plurality of print target positions based on the recognition result of the mask recognition mark and the print position data is maximized under a predetermined condition. By aligning the substrates, even when the substrate causing expansion / contraction deformation is targeted, the positional deviation between the position of the paste printed on the substrate and the component mounting position can be reduced.

The block diagram which shows the structure of the electronic component mounting system of one embodiment of this invention The side view of the screen printing apparatus in the electronic component mounting system of one embodiment of this invention Explanatory drawing of the board | substrate recognition and mask recognition by the screen printing apparatus in the electronic component mounting system of one embodiment of this invention The top view of the electronic component mounting apparatus in the electronic component mounting system of one embodiment of this invention Explanatory drawing of the board | substrate recognition by the electronic component mounting apparatus in the electronic component mounting system of one embodiment of this invention The block diagram which shows the structure of the control system of the electronic component mounting system of one embodiment of this invention The flowchart of the manufacturing process of the mounting substrate in the electronic component mounting system of one embodiment of this invention The flowchart which shows the screen printing method in the electronic component mounting system of one embodiment of this invention Process explanatory drawing of the board | substrate alignment process in the screen printing apparatus of one embodiment of this invention Process explanatory drawing of the board | substrate alignment process in the screen printing apparatus of one embodiment of this invention Process explanatory drawing of the board | substrate alignment process in the screen printing apparatus of one embodiment of this invention

  Next, embodiments of the present invention will be described with reference to the drawings. First, an electronic component mounting system will be described with reference to FIG. In FIG. 1, the electronic component mounting system includes a screen printing device M1, a print inspection device M2, an electronic component mounting device M3, a mounting state inspection device M4, and a reflow device M5, all of which are electronic component mounting devices. The electronic component mounting line 1 is connected by a communication network 2 and is controlled by a management computer 3 as a whole. The electronic component mounting line 1 has a function of mounting an electronic component on a substrate and manufacturing a mounting substrate.

  The screen printing apparatus M1 screen-prints a component bonding paste (solder paste) on the electrodes formed on the substrate. The print inspection apparatus M2 inspects the print state of the paste on the printed substrate. The electronic component mounting apparatus M3 picks up an electronic component from the component supply unit by a mounting head and mounts the electronic component on a printed board. The mounting state inspection apparatus M4 inspects the presence / absence of the electronic component and the displacement on the substrate after the electronic component is mounted. The reflow device M5 heats and melts the solder by heating the substrate after mounting the electronic component, and solder-bonds the electronic component to the substrate.

  Next, the structure and function of the screen printing apparatus M1 will be described with reference to FIG. In FIG. 2, the screen printing apparatus M <b> 1 is configured by disposing a screen printing mechanism 5 above the substrate positioning unit 11. The substrate positioning unit 11 has a function of holding the substrate 4 to be printed and aligning it relative to the screen mask 22 of the screen printing mechanism 5. The substrate positioning unit 11 stacks a Y-axis table 12, an X-axis table 13, and a θ-axis table 14, and further places horizontal base plates 15a and 16a on the upper surface of a horizontal base plate 14a provided on the upper surface of the θ-axis table 14. Are constructed by combining a first Z-axis table 15 and a second Z-axis table 16 that lift and lower each independently.

  Two vertical frames 15b are erected on the base plate 15a, and a substrate transport mechanism 18 is held at the upper end of the vertical frame 15b. The substrate transport mechanism 18 is disposed in the substrate transport direction (X direction--the direction perpendicular to the paper surface in FIG. 1), and supports and transports both ends of the substrate 4 to be printed by the conveyor mechanism. By driving the first Z-axis table 15, the substrate 4 held by the substrate transport mechanism 18 can be moved up and down with respect to the screen printing mechanism 5. A substrate support 17 is detachably mounted on the upper surface of the base plate 16a. The substrate receiving part 17 receives and holds the substrate 4 transported to the printing position by the screen printing mechanism 5 from below.

  By driving the second Z-axis table 16, the substrate receiving part 17 moves up and down with respect to the substrate 4 held by the substrate transport mechanism 18. Then, the substrate receiving portion 17 supports the substrate 4 from the lower surface side by contacting the lower surface of the substrate receiving portion 17 with the lower surface of the substrate 4. The upper surface of the substrate transport mechanism 18 is provided with two clamp members 19 disposed opposite to each other, and the clamp member 19 on one side is advanced and retracted by the drive mechanism 19a, whereby the substrate 4 is clamped and fixed from both sides. To do.

  Next, the screen printing mechanism 5 that prints the paste on the substrate 4 that is disposed above the substrate positioning unit 11 and transported to the printing position will be described. In FIG. 2, the screen printing mechanism 5 has a configuration in which a squeegee unit 23 is horizontally moved by a squeegee moving mechanism 24 above a mask unit 20 having a configuration in which a screen mask 22 is extended on a mask frame 21. Pattern holes 22b and 22c are formed in the screen mask 22. As shown in FIGS. 3B and 3C, the pattern holes 22b and 22c are formed on the substrate 4 in the shape of the electrodes 4b and 4c to be printed. It is provided corresponding to the position.

  A squeegee unit 23 is disposed on the mask unit 20. The squeegee unit 23 has a configuration in which two squeegee raising / lowering mechanisms 27 for raising and lowering a pair of squeegee members 26 arranged opposite to each other are arranged on a horizontal plate 25. By driving the squeegee lifting mechanism 27, the squeegee member 26 moves up and down, and the squeegee member 26 contacts the upper surface of the screen mask 22 in the lowered state. The squeegee unit 23 is reciprocally movable in the horizontal direction by a squeegee moving mechanism 24 configured to rotate the feed screw 24b by a squeegee moving motor 24a.

  A camera unit 28 is disposed between the lower surface of the screen mask 22 and the upper surface of the substrate 4 held by the substrate positioning unit 11 so as to be horizontally movable in the X and Y directions by a camera moving mechanism (not shown). Yes. As shown in FIG. 3A, the camera unit 28 includes a substrate recognition camera 28a for imaging the substrate 4 from above and a mask recognition camera 28b for imaging the screen mask 22 from the lower surface side. By driving the camera moving mechanism to move the camera unit 28, the mask recognition mark 22a formed on the screen mask 22 and the substrate recognition mark 4a formed on the substrate 4 are respectively replaced with the substrate recognition camera 28a and the mask recognition camera 28b. Can be imaged. And the position of the mask recognition mark 22a and the board | substrate recognition mark 4a is detected by recognizing this imaging result by the recognition process part 45 (refer FIG. 6). The substrate recognition camera 28a, the mask recognition camera 28b, and the recognition processing unit 45 constitute first recognition means for recognizing the positions of the mask recognition mark 22a and the substrate recognition mark 4a.

  Next, the printing operation by the screen printing mechanism 5 will be described. First, the substrate transport mechanism 18 carries the substrate 4 to be printed into the printing position and aligns it with the substrate receiving portion 17. Next, the second Z-axis table 16 is driven to raise the substrate receiving portion 17 and receive the lower surface of the substrate 4. Next, after the substrate positioning unit 11 is driven and the substrate 4 is aligned with the screen mask 22, the first Z-axis table 15 is driven to raise the substrate 4 together with the substrate transport mechanism 18, and the pattern hole 22b. , 22c are brought into contact with the lower surface of the screen mask 22 provided. Thereafter, the horizontal position of the substrate 4 is fixed by clamping the substrate 4 with the clamp member 19.

  In this state, one of the two squeegee members 26 is lowered and brought into contact with the screen mask 22 supplied with the paste. Next, by sliding the squeegee member 26 on the screen mask 22 in the squeegeeing direction (Y direction), the paste is printed on the substrate 4 held by the substrate positioning portion 11 through the pattern holes 22b and 22c.

  In the above-described printing operation, the substrate 4 to be printed is correctly aligned with the screen mask 22, and the positions of the electrodes 4b and 4c and the positions of the pattern holes 22b and 22c are accurately matched. Although it is extremely important, the positions of the electrodes 4b and 4c and the positions of the pattern holes 22b and 22c do not always coincide with each other due to expansion and contraction of the substrate 4 with time, and printing is often shifted. For this reason, in the present embodiment, in order to prevent the positional deviation of printing due to such an alignment error between the substrate 4 and the screen mask 22 as much as possible, the positional deviation is corrected by a method described later. .

  Next, the configuration and function of the electronic component mounting apparatus M3 will be described with reference to FIG. In FIG. 4, a substrate transport mechanism 32 is disposed in the X direction at the center of the base 31. The board transport mechanism 32 receives the board 4 after the printing inspection by the printing inspection apparatus M2, and positions and holds the board 4 at a mounting work position by a component mounting mechanism described below. A component supply unit 33 is disposed on both sides of the substrate transport mechanism 32, and a plurality of tape feeders 34 are arranged in parallel on the component supply unit 33. The tape feeder 34 feeds the carrier tape holding the electronic components mounted on the substrate 4 to the component pick-up position by the component mounting mechanism by pitch feeding.

  A Y-axis moving table 36Y equipped with a linear motor-driven linear motion mechanism is arranged in the Y direction at one end of the base 31 in the X direction. Similarly, the Y-axis moving table 36Y has a linear motor-driven linear motion mechanism. Two X-axis moving tables 36X provided with a moving mechanism are coupled so as to reciprocate in the Y direction. A mounting head 37 having a plurality of suction nozzles 37a is mounted on the X-axis moving table 36X so as to be reciprocally movable in the X direction, and the mounting head is driven by driving the Y-axis moving table 36Y and the X-axis moving table 36X. 37 moves horizontally in the X and Y directions.

  Thereby, the mounting head 37 takes out the electronic component P (see FIG. 5A) from the tape feeder 34 of the component supply unit 33, and the component mounting position of the substrate 4 on which the paste is printed and positioned and held by the substrate transport mechanism 32. An electronic component P is mounted on the. The Y-axis movement table 36Y, the X-axis movement table 36X, and the mounting head 37 constitute a component mounting mechanism 35 that mounts the electronic component P on the component mounting position of the substrate 4 on which the paste is printed by the mounting head 37.

  A component recognition camera 39 is disposed on the movement path of the mounting head 37 between the substrate transport mechanism 32 and the component supply unit 33, and the mounting head 37 that has picked up the electronic component from the tape feeder 34 is connected to the component recognition camera 39. By moving upward, the component recognition camera 39 images the electronic component held by the mounting head 37 from below. The mounting head 37 is provided with a substrate recognition camera 38 that is located on the lower surface side of the Y-axis moving table 36Y and moves integrally with the mounting head 37 with the imaging direction facing downward. As shown in FIG. 5A, when the mounting head 37 is moved above the substrate 4 held by the substrate transport mechanism 32, the substrate recognition camera 38 is also moved above the substrate 4 and formed on the substrate 4. The captured substrate recognition mark 4a is imaged. The position of the substrate recognition mark 4a is recognized by performing recognition processing on the imaging result by the recognition processing unit 54 (see FIG. 6). By executing position correction processing using a predetermined position correction algorithm based on the position recognition result, the position of the component mounting point corresponding to the electrodes 4b and 4c formed on the substrate 4 is corrected, and the component mounting position is Desired. In the component mounting operation by the mounting head 37, the electronic component is mounted with the component mounting position corrected in this way as a target.

  Next, the configuration of the control system will be described with reference to FIG. Here, only the control systems of the screen printing device M1 and the electronic component mounting device M3 among the plurality of electronic component mounting devices constituting the electronic component mounting line 1 are described. 6, the management computer 3 includes a data storage unit 30 as an external storage device, and the data storage unit 30 stores work execution data such as print position data 30a and mounting position data 30b. The print position data 30a and the mounting position data 30b are reference data used for the alignment of the substrate 4 in the screen printing apparatus M1, and the print position data 30a includes the arrangement of the pattern holes 22b and 22c and the mask recognition mark 22a. The mounting position data 30b indicates the positional relationship between the component mounting points on the substrate 4, that is, the positional relationship between the electrodes 4b and 4c and the substrate recognition mark 4a.

  A control system of the screen printing apparatus M1 will be described. The communication unit 40 is connected to the communication network 2, and transmission / reception of signals between other units such as the management computer 3 and the print inspection apparatus M 2 and the following units is performed via the communication unit 40. The print control unit 41 controls the screen printing operation by the screen printing mechanism 5. The alignment control unit 42 controls the substrate positioning operation by the substrate positioning unit 11. The storage unit 43 stores a position correction program 43a, printing position data 43b, mounting position data 43c, and position accuracy rank data 43d. The position correction program 43a is an arithmetic processing program that performs position correction for obtaining the print target position for the electrodes 4b, 4c and the like based on the position detection result of the substrate recognition mark 4a on the substrate 4. The printing position data 43b and the mounting position data 43c are work execution data having the same purpose and the same contents as the printing position data 30a and the mounting position data 30b stored in the data storage unit 30. In this example, the data storage unit 30 of the management computer 3 and the storage unit 43 of the screen printing apparatus M1 store these data redundantly. However, only one of these data is stored. It may be.

  The position accuracy rank data 43d is data indicating a mounting position accuracy rank assigned to each component mounting point indicated in the mounting position data 43c. That is, when mounting electronic components on the substrate 4, it is not always necessary to mount all the electronic components with the same position accuracy, and different mounting position accuracy is applied depending on the size and type of the electronic component. The position accuracy rank data 43d is data indicating the ranking of the mounting position accuracy according to the size and type of the electronic component to be mounted.

  The mechanism drive unit 44 is controlled by the print control unit 41 and the alignment control unit 42 to drive the substrate positioning unit 11 and the screen printing mechanism 5. Thereby, the screen printing operation is executed. The recognition processing unit 45 performs recognition processing on the imaging results obtained by the substrate recognition camera 28a and the mask recognition camera 28b. As a result, the position of the mask recognition mark 22a on the screen mask 22 and the position of the substrate recognition mark 4a on the substrate 4 are recognized. The alignment of the substrate 4 to the screen mask 22 is performed by the alignment control unit 42 controlling the substrate positioning unit 11 based on these position recognition results.

  The substrate recognition camera 28a, the mask recognition camera 28b, and the recognition processing unit 45 constitute first mark recognition means for recognizing the mask recognition mark 22a formed on the screen mask 22 and the substrate recognition mark 4a formed on the substrate 4. . The alignment control unit 42 aligns the substrate 4 with respect to the screen mask 22 by controlling the substrate positioning unit 11 based on the recognition result of the first mark recognition unit.

  In the present embodiment, when the alignment control unit 42 executes alignment of the substrate 4, as described below, position correction applied to the substrate 4 in the electronic component mounting apparatus M3, that is, substrate recognition. Based on the recognition result of the mark 4a, the paste for the electrodes 4b and 4c is printed in the screen printing apparatus M1 by correcting the component mounting position for the electrodes 4b and 4c by applying a predetermined position correction algorithm. This is used to set the print target position for the purpose.

  In other words, the positional deviation of the electrodes 4b and 4c due to the expansion and contraction deformation of the substrate 4 due to environmental temperature fluctuations and changes with time, etc. is defined as the position correction program 43a based on the recognition result of the substrate recognition mark in the screen printing apparatus M1. Estimation is performed using the position correction algorithm stored in the storage unit 43. Here, as the position correction algorithm, it is desirable that the print target position is obtained by the same method as the position correction algorithm applied in the mounting position correction in the electronic component mounting apparatus M3. As long as the tendency of position correction is approximate, it may be partially different.

  When the screen mask 22 is aligned with the substrate 4, the expansion / contraction of the screen mask 22 is negligible with respect to the expansion / contraction of the substrate 4. And the expansion / contraction tendency of the pattern holes 22b and 22c in the screen mask 22 do not coincide with each other, and they cannot be completely coincided with each other. For this reason, in the position adjustment for alignment, the pattern holes 22b and 22c of the screen mask 22 and the electrodes 4b and 4c of the substrate 4 are approximately matched with each other in a manner that does not cause any trouble in the solder joint. The position of the substrate 4 is adjusted.

  In the present embodiment, this position adjustment is performed so that the degree of approximate matching becomes a maximum under a predetermined condition. Here, as a predetermined condition, the positional deviation that inevitably occurs is equally distributed so that all the electrodes on the same substrate 4 are substantially the same, or the positional accuracy rank data 43 d stored in the storage unit 43. Various conditions can be set according to the individual mounting mode, such as the condition that the print target position corresponding to the electronic component with the high rank of the mounting position shown is preferentially matched with the pattern hole. ing.

  That is, the alignment control unit 42 obtains a plurality of print target positions where the paste is to be printed on the substrate 4 based on the recognition result of the substrate recognition mark 4a and the mounting position data 43c, and then the recognition result of the mask recognition mark 22a and Based on the print position data 43b, there is a function of aligning the substrate 4 so that the degree to which the plurality of pattern holes 22b and 22c approximately match the plurality of print target positions is maximized under a predetermined condition. .

  A control system of the electronic component mounting apparatus M3 will be described. The communication unit 50 is connected to the communication network 2, and exchange of signals between other units such as the management computer 3 and the screen printing apparatus M 1 and the following units is performed via the communication unit 50. The mounting control unit 51 controls the component mounting operation by the component mounting mechanism 35. The position correction program 52a is an arithmetic processing program for correcting the positions of the electrodes 4b, 4c and the like based on the position detection result of the board recognition mark 4a in the component mounting mechanism 35, and the position correction program 52a of the screen printing apparatus M1. A similar position correction algorithm is used.

  The mounting position data 52b is work execution data having the same purpose and the same contents as the printing position data 30a stored in the data storage unit 30. The position accuracy rank data 52c is data having the same purpose and the same content as the position accuracy rank data 43d stored in the storage unit 43 in the screen printing apparatus M1. In this example, the data storage unit 30 of the management computer 3 and the storage unit 52 of the electronic component mounting apparatus M3 store these data redundantly. However, only one of these data is stored. You may do it.

  The mechanism driving unit 53 is controlled by the mounting control unit 51 to drive the substrate transport mechanism 32 and the component mounting mechanism 35. Thereby, a component mounting operation is executed. The recognition processing unit 54 performs recognition processing on the imaging results obtained by the board recognition camera 38 and the component recognition camera 39. As a result, the position of the substrate recognition mark 4a on the substrate 4 positioned and held by the substrate transport mechanism 32 and the electronic component held by the mounting head 37 are recognized. The electronic component P is mounted on the substrate 4 by the mounting control unit 51 controlling the component mounting mechanism 35 based on the position recognition results. The substrate recognition camera 38 and the recognition processing unit 54 constitute second mark recognition means for recognizing the substrate recognition mark 4a formed on the substrate 4 in the print inspection apparatus M2. The mounting control unit 51 mounts the electronic component P on the substrate 4 by controlling the component mounting mechanism 35 based on the recognition result of the second mark recognition means.

  Next, a method for manufacturing a mounting board in the electronic component mounting system shown in FIG. 1 will be described with reference to FIG. In FIG. 7, first, the work substrate 4 is carried into the screen printing apparatus M1 (ST1). Next, first mark recognition is performed (ST2). That is, the mask recognition mark 22a formed on the screen mask 22 and the substrate recognition mark 4a formed on the substrate 4 are imaged by the mask recognition camera 28b and the substrate recognition camera 28a, respectively, and the imaging result is recognized by the recognition processing unit 45. By processing, the positions of the mask recognition mark 22a and the substrate recognition mark 4a are recognized (first mark recognition step).

  Next, alignment control for aligning the substrate 4 with respect to the screen mask 22 is executed based on the mark recognition result in the first mark recognition step (ST3). That is, the alignment control unit 42 controls the substrate positioning unit 11 based on the recognition result obtained in the first mark recognition process, thereby aligning the substrate 4 with respect to the screen mask 22 (alignment control process). ).

  Next, screen printing is executed (ST4). That is, by sliding the squeegee member 26 on the screen mask 22 supplied with the paste, the paste is applied to the substrate 4 positioned and held in the substrate positioning portion 11 through the pattern holes 22b and 22c formed in the screen mask 22. Printing (screen printing process). Then, the board | substrate 4 is carried in to the printing test | inspection apparatus M2, and the quality of the printing state of the printed paste is imaged optically by imaging the board | substrate 4 (ST5). And the board | substrate 4 determined that the printing state is favorable here is carried in to the electronic component mounting apparatus M3 (ST6).

  Next, second mark recognition is performed (ST7). That is, the substrate 4 is imaged by the substrate recognition camera 38, and the image processing result is recognized by the recognition processing unit 54, thereby recognizing the position of the substrate recognition mark 4a (second mark recognition step). Next, an electronic component mounting operation by the component mounting mechanism 35 is executed (ST8). Then, the substrate 4 after mounting the electronic component is carried into the mounting state inspection apparatus M4, and the mounting state inspection is executed (ST9). If it is determined that the mounting state is good, the substrate 4 is carried into the reflow apparatus M5 (ST10). Here, by heating the substrate 4 according to a predetermined heating profile, the solder in the paste is melted and the electronic component P is soldered to the substrate 4. Thereby, the manufacturing process of the mounting substrate is completed.

  In the mounting board manufacturing process described above, the screen printing apparatus M1 applies the first mark recognition process and the recognition result obtained in the first mark recognition process to the screen mask 22 prior to the screen printing process. On the other hand, an alignment control process for aligning the substrate 4 is performed. The electronic component mounting apparatus M3 executes a second mark recognition process for recognizing the board recognition mark 4a prior to the component mounting process by the component mounting mechanism 35, and is obtained in the second mark recognition process in the component mounting process. The electronic component P is mounted at the component mounting position based on the recognition result.

  Then, in the alignment control process, a plurality of print target positions where the paste is to be printed on the board 4 is obtained based on the recognition result of the board recognition mark 4a in the first mark recognition process and the mounting position data 43c, and then the mask recognition mark Based on the recognition result 22a and the print position data 43b, the substrate 4 is aligned so that the degree to which the plurality of pattern holes 22b and 22c approximately match the plurality of print target positions is maximized under a predetermined condition. Like to do.

  In the subsequent component mounting step, the position of the component mounting point is corrected according to a predetermined position correction algorithm based on the recognition result in the second mark recognition step, and the electronic component P is actually mounted by the mounting head 37. Find the component mounting position when doing this. Here, by obtaining a plurality of print target positions by a method similar to the position correction algorithm used in the component mounting process in the alignment control process, the component mounting position and the print target position can be approximated as much as possible. Thereby, it is possible to reduce problems caused by the positional deviation between the printed paste and the mounted electronic component P.

  Next, in the electronic component mounting system described above, prior to electronic component mounting by the electronic component mounting device M3, a screen in the electronic component mounting system in which paste for component bonding is printed on the electrodes formed on the substrate 4 by the screen printing device M1. The printing method will be described with reference to FIGS. 9 to 11 in accordance with the flow of FIG.

  First, the substrate 4 to be worked is carried into the screen printing apparatus M1 (ST21), and the substrate 4 is clamped by the substrate positioning unit 11 in a state where the substrate 4 is received by the substrate receiving unit 17 (ST22). As shown in FIG. 9A, a substrate recognition mark 4a for position recognition formed at a diagonal position and electrodes 4b and 4c for mounting different types of electronic components by solder bonding are formed on the substrate 4. Has been. Next, the camera unit 28 is moved, and the substrate recognition mark 4a and the mask recognition mark 22a are recognized by the substrate recognition camera 28a and the mask recognition camera 28b (ST23). As a result, as shown in FIG. 9B, a positional deviation of the substrate recognition mark 4a from the normal position (see the substrate recognition mark 4a * indicated by a broken line) is detected. Here, the direction of displacement and the amount of displacement are indicated by vectors with arrows a1 and a2.

  Next, the print target position is calculated based on the recognition result of the substrate recognition mark 4a (ST24). That is, by converting the position coordinates of the electrodes 4b and 4c indicated by the mounting position data 43c into position coordinates on the correction coordinate system corrected by the positional deviation of the substrate recognition mark 4a according to a predetermined position correction algorithm, FIG. As shown in FIG. 9B, the positions of the electrodes 4b and 4c displaced by the arrows b1 and b2 and the arrows c1 and c2 from the normal positions (see the electrodes 4b * and 4c * shown by broken lines) are calculated as the print target positions. Is done.

  As the position correction algorithm used here, a position correction calculation formula using a coordinate conversion formula known in the technical field is appropriately selected and used. By executing such a position correction calculation, it is possible to efficiently obtain the print target position without recognizing the actual electrodes 4b and 4c on the substrate 4. Here, an example is shown in which two substrate recognition marks 4a arranged at diagonal positions of the substrate 4 are used. However, when three or more substrate recognition marks 4a are formed in order to improve position correction accuracy. It may be.

  Next, the substrate 4 is aligned with the screen mask 22 based on the print target position obtained by the calculation (ST25). Here, the positions of the pattern holes 22b and 22c in the mask unit 20 shown in FIG. 9C correspond to the electrodes 4b and 4c in FIG. 9B. Therefore, when aligning the substrate 4 with the screen mask 22, it is necessary to adjust the relative positions of the electrode 4b *, the electrodes 4b, 4c *, and the electrode 4c. This relative position adjustment will be described.

  10A and 10B show alignment reference lines for the screen mask 22 and the substrate 4. That is, in the mask unit 20 shown in FIG. 10A, by recognizing the two mask recognition marks 22a, the mask X axis 22X and the mask Y axis 22Y orthogonal to the XY direction through the center point 22CP of the screen mask 22 are recognized. Is required. Similarly, in the substrate 4 shown in FIG. 10B, by recognizing the two substrate recognition marks 4a, the substrate X axis 4X and the substrate Y axis 4Y orthogonal to the XY direction pass through the center point 4CP of the substrate 4. Desired. As shown in FIG. 10C, δy indicating the offset amount in the Y direction between the mask X axis 22X and the substrate X axis 4X, and δx indicating the offset amount in the X direction between the mask Y axis 22Y and the substrate Y axis 4Y. Is specified to define the manner in which the substrate 4 is aligned with the screen mask 22.

  That is, when aligning the substrate 4, it is desirable that the degree of matching between the electrode and the pattern hole is higher, but it is not possible to completely match the pattern hole for all the electrodes. In order to maximize the degree of coincidence, it is necessary to set some alignment conditions. FIG. 11 shows three modes based on different alignment conditions when aligning the substrate 4 with respect to the screen mask 22 in this way. The selection of these modes is performed based on the rank of the mounting position accuracy indicated in the position accuracy rank data 43d stored in the storage unit 43.

  By specifying (δx1, δy1) shown in FIG. 11A, an alignment mode is realized when the ranks of required mounting position accuracy are equal for any electronic component to be mounted. That is, in this case, the alignment condition is that the degree of positional deviation between the electrode 4b and the pattern hole 22b and the degree of positional deviation between the electrode 4c and the pattern hole 22c are approximately equal. The substrate 4 is aligned with the screen mask 22.

  In addition, by specifying (δx2, δy2) shown in FIG. 11B, an alignment mode when the rank of the mounting position accuracy of the electronic component mounted on the electrode 4c is higher than other electronic components is realized. The That is, in this case, priority is given to the alignment between the electrode 4c and the pattern hole 22c, the positional deviation between the electrode 4c and the pattern hole 22c is almost zero, and the electrode 4b and the pattern hole 22b The substrate 4 is aligned with respect to the screen mask 22 in such a manner as to allow the positional deviation.

  Then, by specifying (δx3, δy3) shown in FIG. 11C, an alignment mode in the case where the rank of the mounting position accuracy of the electronic component mounted on the electrode 4b is higher than that of other electronic components is realized. The That is, in this case, priority is given to the alignment between the electrode 4b and the pattern hole 22b. The positional deviation between the electrode 4b and the pattern hole 22b is almost zero, and the electrode 4c and the pattern hole 22c The substrate 4 is aligned with respect to the screen mask 22 in such a manner as to allow the positional deviation. As in the above example, it is assumed that some displacement is allowed instead of making the position of the electrode and the pattern hole completely match for one electronic component. A weighting method for adjusting the amount may be used.

  After the alignment of the substrate 4 is completed in this way, the first Z-axis table 15 is driven to raise the clamped substrate 4 and contact the screen mask 22 (ST26). Next, a squeegeeing operation is performed in which the squeegee member 26 is slid in a state where the squeegee member 26 is in contact with the upper surface of the screen mask 22 supplied with the paste (ST27). Thus, the paste is printed on the electrodes 4b and 4c of the substrate 4 through the pattern holes 22b and 22c. Thereafter, a plate separating operation for lowering the substrate 4 and separating it from the lower surface of the screen mask 22 is executed (ST28), thereby completing the screen printing operation (ST29).

  As described above, in the screen printing used in the electronic component mounting system shown in the present embodiment, the mask recognition mark 22a and the substrate recognition mark 4a are recognized prior to the screen printing process for printing the paste on the substrate 4. Based on the recognition result obtained in the first mark recognition step and the mounting position data 43c stored in advance, a plurality of print target positions where the paste is to be printed on the substrate 4 are obtained, and then the recognition result of the mask recognition mark 22a. In addition, the substrate 4 is aligned so that the degree to which the plurality of pattern holes approximately coincide with the plurality of print target positions is maximized under a predetermined condition based on the print position data 43b. As a result, even when the substrate 4 that causes expansion / contraction deformation is targeted, it is possible to reduce the positional deviation between the position of the paste printed on the substrate 4 and the component mounting position.

  The electronic component mounting system and the mounting substrate manufacturing method of the present invention reduce misalignment between the position of the solder paste printed on the substrate and the component mounting position even when the substrate is subject to expansion / contraction deformation. It is advantageous in that it can be used, and is useful in the field of manufacturing a mounting substrate by connecting a plurality of electronic component mounting apparatuses to each other and mounting the electronic component on the substrate by solder bonding.

DESCRIPTION OF SYMBOLS 1 Electronic component mounting line 2 Communication network 3 Management computer 4 Board | substrate 4a Board | substrate recognition mark 4b, 4c Electrode 5 Screen printing mechanism 11 Board | substrate positioning part 22 Screen mask 22a Mask recognition mark 22b, 22c Pattern hole 23 Squeegee unit 28a Board | substrate recognition camera 28b Mask Recognition camera 33 Component supply unit 35 Component mounting mechanism 37 Mounting head 38 Substrate recognition camera P Electronic component

Claims (4)

In an electronic component mounting system configured to connect a plurality of electronic component mounting apparatuses and mount electronic components on a substrate to manufacture a mounting substrate, the electronic component is picked up from a component supply unit by a mounting head and mounted on the substrate A screen printing apparatus in an electronic component mounting system that is disposed on the upstream side of an electronic component mounting apparatus and prints a paste for component bonding on an electrode formed on the substrate,
A screen printing mechanism that prints the paste on the substrate that is positioned and held in the substrate positioning portion through a pattern hole formed in the screen mask by sliding a squeegee on the screen mask supplied with the paste;
Mark recognition means for recognizing a mask recognition mark formed on the screen mask and a substrate recognition mark formed on the substrate;
An alignment control unit that aligns the substrate with respect to the screen mask by controlling the substrate positioning unit based on a recognition result of the mark recognition unit;
Reference data used in the alignment of the board, the printing position data indicating the positional relationship between the arrangement of the pattern holes and the mask recognition mark, and the position of the component mounting point on the board and the position of the board recognition mark A data storage unit that stores mounting position data indicating the relationship for each board type,
The alignment control unit obtains a plurality of print target positions where the paste is to be printed on the substrate according to a predetermined position correction algorithm based on the recognition result of the substrate recognition mark and the mounting position data, and then the mask recognition mark The substrate is aligned so that the degree to which the plurality of pattern holes approximately coincide with the plurality of print target positions is maximized under a predetermined condition based on a recognition result and the print position data. Screen printing apparatus in electronic component mounting system.   The component mounting points are given different ranks of mounting position accuracy depending on the size and type of electronic components to be mounted, and the predetermined condition corresponds to the electronic component having a high rank of mounting position accuracy. 2. The screen printing apparatus in an electronic component mounting system according to claim 1, wherein the pattern hole is preferentially matched with a print target position. In an electronic component mounting system configured to connect a plurality of electronic component mounting apparatuses and mount electronic components on a substrate to manufacture a mounting substrate, the electronic component is picked up from a component supply unit by a mounting head and mounted on the substrate Prior to electronic component mounting, a screen printing method in an electronic component mounting system for printing a component bonding paste on an electrode formed on the substrate,
Prior to the screen printing step of printing the paste on the substrate positioned and held in the substrate positioning portion through the pattern hole formed in the screen mask by sliding the squeegee on the screen mask supplied with the paste. And recognizing the mask recognition mark formed on the screen mask and the substrate recognition mark formed on the substrate, and controlling the substrate positioning unit based on the recognition result obtained in the mark recognition step. And performing an alignment control step of aligning the substrate with respect to the screen mask,
In the alignment control step, in the board according to a predetermined position correction algorithm based on the recognition result of the board recognition mark and the mounting position data indicating the positional relationship between the position of the component mounting point on the board and the board recognition mark. A plurality of print target positions where the paste is to be printed are obtained, and then a plurality of print target positions are printed based on the recognition result of the mask recognition mark and print position data indicating the positional relationship between the pattern hole array and the mask recognition mark. A screen printing method in an electronic component mounting system, characterized in that the substrate is aligned so that the degree to which the pattern holes approximately match is maximized under a predetermined condition.   The component mounting point is given a rank of mounting position accuracy according to the size and type of the electronic component to be mounted, and the predetermined condition is the printing corresponding to an electronic component having a high rank of mounting position accuracy. 4. The screen printing method in an electronic component mounting system according to claim 3, wherein the condition is such that the pattern hole is preferentially matched with a target position.

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