JP2018202691A - Screen printing system and screen printing method - Google Patents

Abstract

To provide a screen printing system and a screen printing method each of which enables productivity to be improved while preventing the printing failure in the multiple-sheet system.SOLUTION: A screen printing system performing work on a carrier 9 on which a plurality of pieces of workpiece 10 are arranged comprises: a carrier support part which supports the carrier 9 below a mask plate 22; a backup part 6 which lifts up one of the plurality of pieces of workpiece 10 from the carrier 9 to abut it the lower surface of the mask plate 22; an alignment mechanism which relatively moves the backup part 6 and the mask plate 22; and a print head 13 which prints the paste on the workpiece 10 abutting on the lower surface of the mask plate 22, through a pattern hole from the upper surface of the mask plate 22. The lower surface of the mask plate 22 is supported by a mask plate support part 7 when at least the print head 13 performs printing on the workpiece 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a screen printing system and a screen printing method for printing a paste on a workpiece such as a substrate.

  In the electronic component manufacturing field, screen printing is widely used as a method for printing paste such as cream solder or conductive paste on a substrate. When the substrate to be printed is a small unit substrate, so-called multi-chip manufacturing, in which a plurality of unit substrates are formed on a single parent substrate, is widely adopted for the purpose of improving productivity. ing. However, along with the widespread use of such a multi-sheet picking method, the problem of printing misalignment due to various factors as described below has become apparent.

  In other words, since a small unit board that is subject to multi-chip collection is required to be inexpensive in price, the degree of expansion and contraction due to changes in board dimensions over time due to the board material is higher than that of conventional boards. Tend to be larger. Furthermore, with the miniaturization of the product, the wiring pattern of the unit substrate is miniaturized, and the degree of fineness of the print pattern required by screen printing is higher than ever before. Due to such factors, the degree of printing position deviation in screen printing exceeding a permissible range and causing printing failure is increased, and further, mounting failure due to printing position deviation is caused.

  In order to eliminate the difficulty in such a multi-sheet picking method, there has been proposed a screen printing method in which individual substrates obtained by dividing a parent substrate into a plurality of pieces are sequentially printed individually (see, for example, Patent Document 1). . In the prior art shown in this patent document example, a print target substrate to be printed out of a plurality of individual substrates placed on a pallet is first lifted from the pallet by a backup device. Next, position detection is performed to correctly align the individual substrate with the opening of the screen mask. Based on the position detection result, the individual substrate is brought into contact with the opening of the screen mask, and screen printing is performed on the substrate to be printed.

International Publication No. 2017/022127

  However, in the prior art shown in the above-mentioned patent documents, the following problems are difficult to avoid in the screen printing operation due to the support form of the individual substrate and the screen mask when the substrate to be printed is brought into contact with the screen mask. It was. That is, in this prior art, the substrate to be printed is lifted to the upper surface of the block of the backup device and comes into contact with the lower surface of the screen mask.

  At this time, the screen mask around the substrate to be printed is not supported from the lower surface side, and in the squeegeeing in which the squeegee is moved on the upper surface of the mask plate, the screen mask is not received in a range away from the substrate to be printed. The printing pressure in squeezing acts on the mask plate as it is. When squeezing is performed in such a state, the mask plate is bent and deformed, resulting in problems such as bending of the peripheral edge of the substrate and poor adhesion between the mask plate and the printed surface of the substrate, leading to defective printing. As described above, in the conventional screen printing employing the multi-sheet-taking method, there is a problem that it is difficult to improve productivity while preventing printing defects.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a screen printing system and a screen printing method that can improve productivity while preventing printing defects in a multi-sheet picking system.

  The screen printing system of the present invention includes a mask plate in which a pattern hole for printing is formed, a carrier on which a plurality of workpieces are arranged, a carrier support portion that supports the carrier below the mask plate, and the carrier support portion. A backup unit that lifts one of the plurality of workpieces from the carrier supported by the carrier and contacts the lower surface of the mask plate; and the workpiece lifted by the backup unit and the mask plate for aligning the mask plate An alignment mechanism that relatively moves the backup unit and the mask plate; a print head that prints a paste from a top surface of the mask plate to a work contacting the bottom surface of the mask plate through the pattern hole; and at least the print head includes When printing on a workpiece, the mask A mask plate supporting portion for supporting the lower surface of the over bets, including a.

  The screen printing method of the present invention includes a carrier placement step of placing a carrier on which a plurality of workpieces are placed on a printing stage, and pushing one of the plurality of workpieces from below from the carrier placed on the printing stage. A backup step of lifting, a mask plate placement step of positioning the mask plate above the workpiece by aligning the workpiece lifted in the backup step with the mask plate on which a pattern hole for printing is formed, and the mask plate A printing process for printing paste on the workpiece through the pattern hole by moving the printing head while pressing a printing head on the upper surface, a mask plate supporting process for supporting the lower surface of the mask plate at least during the printing process, and the printing process The work supporting part is transferred to the workpiece that has been finished. A workpiece placing step for placing on the supported carrier, and a plurality of workpieces, the backup step, the mask plate placement step alignment step, the printing step, the mask plate supporting step, and the workpiece placement. The paste is printed on the plurality of workpieces by sequentially executing the placing step.

  According to the present invention, productivity can be improved while preventing printing defects in the multi-sheet taking system.

The front view of the screen printing apparatus which comprises the screen printing system of Embodiment 1 of this invention. Structure explanatory drawing of the printing head and printing stage of the screen printing apparatus in Embodiment 1 of this invention The top view of the printing stage of the screen printing apparatus in Embodiment 1 of this invention The perspective view of the carrier holding the workpiece | work used as the printing object of the screen printing apparatus in Embodiment 1 of this invention. Explanatory drawing of the workpiece | work holding | maintenance by the carrier in the screen printing system of Embodiment 1 of this invention. 1 is a block diagram showing a configuration of a control system of a screen printing apparatus in Embodiment 1 of the present invention. The flowchart which shows the screen printing method by the screen printing system of Embodiment 1 of this invention. Operation explanatory diagram showing the screen printing method according to the first embodiment of the present invention. Operation explanatory diagram showing the screen printing method according to the first embodiment of the present invention. Operation explanatory diagram showing the screen printing method according to the first embodiment of the present invention. Operation explanatory diagram showing the screen printing method according to the first embodiment of the present invention. Operation explanatory diagram showing the screen printing method according to the first embodiment of the present invention. Operation explanatory diagram showing the screen printing method according to the first embodiment of the present invention. Operation explanatory diagram showing the screen printing method according to the first embodiment of the present invention. Operation explanatory diagram showing the screen printing method according to the first embodiment of the present invention. Explanatory drawing of the workpiece | work holding | maintenance by the carrier in the screen printing system of Embodiment 2 of this invention. Operation explanatory diagram showing the screen printing method according to the second embodiment of the present invention. Explanatory drawing of the workpiece | work holding | maintenance by the carrier in the screen printing system of Embodiment 3 of this invention. Explanatory drawing of the backup of the workpiece | work in the screen printing system of Embodiment 3 of this invention Operation explanatory diagram showing the screen printing method in Embodiment 3 of the present invention Explanatory drawing of the workpiece | work holding | maintenance by the carrier in the screen printing system of Embodiment 4 of this invention. Operation explanatory diagram showing a screen printing method according to Embodiment 4 of the present invention. Operation explanatory diagram showing a screen printing method in Embodiment 5 of the present invention

  Next, embodiments of the present invention will be described with reference to the drawings. First, the configuration of the screen printing apparatus 1 constituting the screen printing system of the first embodiment will be described with reference to FIGS. 1 and 2. This screen printing system has a function of printing paste such as cream solder on a work such as a substrate placed on a carrier. In the present embodiment, a screen printing system is configured by the screen printing apparatus 1 and a carrier on which a plurality of works are arranged.

  In FIG. 1, support frames 11 are erected on both side ends in the X direction of the base 1a. Between the pair of support frames 11, the following elements constituting the screen printing apparatus 1 are provided. In the present embodiment, the horizontal direction in FIG. 1, that is, the workpiece conveyance direction for conveying the work target carrier 9 is defined as the X direction, and the direction orthogonal to the X direction is defined as the Y direction.

  Here, with reference to FIG. 4 and FIG. 5, the workpiece | work 10 used as the work object in this screen printing system and the carrier 9 by which the workpiece | work 10 is arrange | positioned are demonstrated. As shown in FIG. 4, the carrier 9 is a rectangular workpiece holder, and holds a plurality of workpieces 10 such as a substrate in a predetermined regular arrangement.

  As shown in FIG. 5, the work 10 is a rectangular plate-shaped substrate, and a plurality of connection electrodes 10 a are formed on the upper surface. In screen printing by the screen printing apparatus 1, the paste P is printed on the electrode 10a through the pattern hole formed in the pattern hole forming region 22a (see FIG. 2) of the mask plate 22. At a diagonal position on the upper surface of the work 10, a pair of position recognition work recognition marks 10m are formed.

  On the upper surface of the carrier 9, a plurality of workpiece storage recesses 9a for arranging the workpiece 10 are formed in a predetermined arrangement. A first opening 9b formed through the carrier 9 in the up and down direction is provided at the bottom of the workpiece housing recess 9a. In the printing operation for the workpiece 10, the workpiece 10 disposed in the workpiece storage recess 9 a is lifted through the first opening 9 b by the backup unit 6 (see FIG. 2). Further, the carrier 9 is formed with an engagement hole 9c for locking the position of the carrier 9 by the carrier transport mechanism 20 (see FIG. 3). Note that in the carrier 9 shown in the operation explanatory diagrams of FIGS. 8 to 15, only the first opening 9 b is illustrated with the illustration of the workpiece housing recess 9 a omitted.

  In FIG. 1, a printing stage 2 that is moved by a printing stage moving mechanism 3 is provided on the upper surface of a base 1 a between a pair of support frames 11. The printing stage moving mechanism 3 has a configuration in which a printing stage elevating mechanism 3z is stacked on a printing stage XYΘ table 3xyθ. By driving the printing stage XYΘ table 3xyθ, the printing stage 2 moves horizontally in the X direction, the Y direction, and the Θ direction. The printing stage 2 moves up and down by driving the printing stage lifting mechanism 3z.

  The printing stage 2 has a function of supporting a carrier 9 (see FIG. 4) on which a plurality of workpieces 10 to be printed carried from the upstream side are arranged and aligning with a screen printing mechanism described below. ing. As shown in FIG. 2, the screen printing mechanism includes a mask plate 22 in which pattern holes, which are printing openings, are formed in the pattern hole forming region 22a, and a print head 13 that performs a squeezing operation on the mask plate 22. ing.

  The configuration and function of the printing stage 2 will be described with reference to FIGS. FIG. 3 shows the plane of the printing stage 2 as viewed from above. In FIG. 2, the printing stage 2 includes a lifting table 4 coupled to the upper surface of the printing stage lifting mechanism 3z. Support members 4 a are erected on both ends of the upper surface of the lifting table 4. A conveyor guide portion 4b extending in the X direction is coupled to the upper end portion of the support member 4a.

  A printing stage conveyor 8b is provided on the inner side surface of the conveyor guide portion 4b. The printing stage conveyor 8b conveys the carrier 9 in the X direction by running a conveyor belt on which the carrier 9 is placed. The printing stage conveyor 8b can be connected to a carry-in conveyor 8a and a carry-out conveyor 8c that pass through openings provided in the upstream and downstream support frames 11, respectively. As shown in FIG. 1, the carrier 9 carried in (arrow a) by the carry-in conveyor 8 a is delivered to and supported by the printing stage conveyor 8 b provided in the printing stage 2. Then, the work 10 after the screen printing is completed in the printing stage 2 is transferred from the printing stage conveyor 8b to the carry-out conveyor 8c and carried out.

  As shown in FIG. 3, in the printing stage 2, the printing stage conveyor 8b is arrange | positioned along with the inner surface side of the conveyor guide part 4b. The carrier 9 transferred to the printing stage conveyor 8b is supported from below by a pair of conveying belts constituting the printing stage conveyor 8b at two opposing edges (see FIG. 9). Therefore, the printing stage conveyor 8 b is a carrier support portion that supports the carrier 9 below the mask plate 22. The printing operation by the above-described screen printing mechanism is executed for the carrier 9 supported by the carrier support unit.

  A carrier transport mechanism 20 is attached to the printing stage conveyor 8b on one side along the X direction. The carrier transport mechanism 20 has a function of positioning the carrier 9 in the printing stage 2, and an engaging portion 20 a configured to project and retract an engaging pin 20 c that engages with an engaging hole 9 c formed in the carrier 9. And an engaging portion moving shaft 20b for moving the engaging portion 20a in the X direction. With the engagement pin 20c engaged with the engagement hole 9c of the carrier 9, the engagement portion 20a is moved to the positioning reference position set corresponding to each work 10 to be worked by the engagement portion moving shaft 20b. By moving, the first opening 9b in which the work 10 to be worked is arranged can be aligned directly above the backup unit 6 (see FIG. 8).

  On the upper surface of the elevating table 4, a backup support member 5 that is driven up and down by a backup elevating mechanism 5a is provided in a horizontal posture. As shown in FIG. 3, the backup support member 5 is a flat plate-like member that is elongated in the X direction, and a backup unit 6 is erected at the center of the backup support member 5. The planar shape of the upper end surface of the backup unit 6 is a shape that can support the workpiece 10 to be printed from below. A work suction hole 6 a for sucking and holding the work 10 is formed on the upper end surface of the backup unit 6.

  The backup unit 6 has a function of lifting one of the plurality of workpieces 10 from the carrier 9 supported by the printing stage conveyor 8b, which is a carrier support unit, and bringing it into contact with the lower surface of the mask plate 22. At this time, the above-described function of the carrier transport mechanism 20 is used to align a desired workpiece 10 to be worked among the plurality of workpieces 10 with respect to the backup unit 6.

  Further, a rectangular and long rectangular mask plate support portion 7 is arranged in a horizontal posture at the upper end portion of the support post 7a erected on both ends of the backup support member 5 in the X direction. The mask plate support unit 7 has a function of contacting and supporting the lower surface of the mask plate 22 when the print head 13 performs printing on the workpiece 10. Here, the height of the backup portion 6 and the mask plate support portion 7 is such that the upper surface 6b of the backup portion 6 is positioned lower than the upper surface 7b of the mask plate support portion 7 by at least the thickness t of the workpiece 10. Settings have been made (see FIG. 10).

  The back-and-forth operation required for the backup unit 6 and the mask plate support unit 7 to perform the above-described functions is performed as follows. That is, when the carrier 9 is carried into the printing stage conveyor 8b, the backup lifting mechanism 5a is driven to raise the backup support member 5, whereby both the backup unit 6 and the mask plate support unit 7 are raised. As described above, the backup unit 6 and the mask plate support unit 7 are moved up and down by the common backup lifting mechanism 5a.

  At this time, the backup unit 6 is raised with respect to the carrier 9 in a state where one of the plurality of first openings 9 b formed in the carrier 9 is located immediately above the backup unit 6. As a result, the backup unit 6 lifts one of the plurality of workpieces 10 through the first opening 9b formed through the carrier 9 in the vertical direction. The lifted work 10 comes into contact with the lower surface of the mask plate 22, and in this state, a screen printing operation is performed to move the print head 13 in the squeezing direction. As a result, the print head 13 prints the paste P on the workpiece 10 contacting the lower surface of the mask plate 22 through the pattern holes formed in the pattern hole forming region 22a from the upper surface of the mask plate 22.

  In this screen printing operation, at least when the print head 13 performs printing on the workpiece 10, the mask plate support portion 7 that is in the raised state and is in contact with the lower surface of the mask plate 22 supports the lower surface of the mask plate 22. It has become. That is, as described above, the upper surface 6b of the backup unit 6 and the mask plate support unit 7 are positioned so as to be at least lower than the upper surface 7b of the mask plate support unit 7 by the thickness t of the workpiece 10. The height dimension is set.

  As a result, the upper surface 7 b of the mask plate support 7 is surely in contact with the lower surface of the mask plate 22 in a state where the upper surface of the workpiece 10 lifted by the backup unit 6 is in contact with the mask plate 22. In this way, by supporting the lower surface of the mask plate 22 by the mask plate support portion 7 in the screen printing operation, the deflection of the mask plate 22 due to the printing pressure of the print head 13 acting on the mask plate 22 from the upper surface is reduced. The Thereby, it is possible to suppress printing defects caused by the edge of the workpiece 10 hitting the mask plate 22 or the like.

  In the above configuration, the printing stage conveyor 8b is a carrier support unit that supports the carrier 9 in which a plurality of workpieces 10 are arranged below the mask plate 22, and the upper surfaces of the pair of conveying belts of the printing stage conveyor 8b are opposed to the carrier 9. It is a pair of carrier support surface which supports a pair of edge part to perform from the bottom. The mask plate support portion 7 that contacts and supports the lower surface of the mask plate 22 is disposed in a space sandwiched between the pair of carrier support surfaces, and is further a space outside the carrier 9 supported by the printing stage conveyor 8b. (Refer to the mask plate support 7 shown in FIG. 9).

  In order to align the workpiece 10 lifted by the backup unit 6 and the mask plate 22, an alignment operation is performed in which the backup unit 6 and the mask plate 22 are relatively moved to perform alignment. That is, the printing stage XYΘ table 3xyθ that moves the printing stage 2 provided with the printing stage conveyor 8b serving as the carrier support portion in the horizontal direction is an alignment mechanism for performing the above-described alignment operation.

  A print head support beam 12 that supports the print head 13 is disposed at the upper ends of the pair of support frames 11 so as to be movable in the Y direction via a linear motion guide mechanism 12a. One end of the print head support beam 12 is coupled to one support frame 11 via a print head moving mechanism 14. The print head moving mechanism 14 moves the print head support beam 12 in the Y direction by a linear motion mechanism that uses a print head motor (not shown) as a drive source. By driving the print head moving mechanism 14, the print head 13 supported by the print head support beam 12 reciprocates in the Y direction that is the squeezing direction.

  The print head 13 includes a squeegee 13 b that extends downward from the print head support beam 12. By driving a squeegee driving unit 13 a provided on the upper surface of the print head support beam 12, the squeegee 13 b descends and comes into sliding contact with the mask plate 22. In this state, the print head 13 is moved by the print head moving mechanism 14, whereby the screen printing operation described above is executed.

  Between the upper surface of the printing stage 2 and the lower surface of the mask plate 22, a moving mechanism (see the camera moving mechanism 16 shown in FIG. 6) for moving the camera mounting base 17 in the X direction and the Y direction is provided. A first camera 18 and a second camera 19 are attached to the camera mounting base 17. This moving mechanism includes a camera X axis moving mechanism 16X that moves the camera mounting base 17 in the X direction along the camera X axis beam 15, and a camera Y axis moving mechanism 16Y that moves the camera X axis beam 15 in the Y direction. The The movement of the camera X-axis beam 15 in the Y direction is guided by a linear motion guide mechanism 15 c disposed on the inner surface of the support frame 11.

  The camera X-axis moving mechanism 16X includes a camera X-axis motor 15a, a feed screw 15b, and a nut portion (not shown) coupled to the camera mounting base 17 shown in FIG. The camera Y-axis moving mechanism 16Y is configured to move the camera X-axis beam 15 in the Y direction by a linear motion mechanism that uses a camera Y-axis motor (not shown) as a drive source. By driving the camera Y-axis moving mechanism 16Y, the camera X-axis beam 15 moves in the Y direction.

  Here, functions of the first camera 18 and the second camera 19 will be described. The first camera 18 is arranged with the imaging direction facing downward, and images the workpiece recognition mark 10 m (see FIG. 4) of the workpiece 10 held by the carrier 9 in the printing stage 2. The imaging result is recognized and processed by the processing function of the workpiece recognition unit 32 (see FIG. 6), so that the position of the electrode 10a in the workpiece 10 is detected in addition to the position and direction of the workpiece 10. Therefore, the first camera 18 and the workpiece recognition unit 32 are workpiece position detection units that detect the position by imaging the plurality of workpieces 10 on the carrier 9 with the first camera 18.

  The second camera 19 is arranged with the imaging direction facing upward, and images a mask recognition mark (not shown) formed on the mask plate 22. The imaging result is recognized by the processing function of the mask recognition unit 31 (see FIG. 6), whereby the mask center and the position of the pattern hole forming region 22a on the mask plate 22 are recognized. Therefore, the second camera 19 and the mask recognizing unit 31 are mask position detecting units that detect the position by imaging the mask plate 22 with the second camera 19.

  Next, the configuration of the control system of the screen printing apparatus 1 will be described with reference to FIG. 6, the control unit 30 includes a print head 13, a print head moving mechanism 14, a first camera 18, a second camera 19, a camera moving mechanism 16, a backup lifting mechanism 5a, a printing stage lifting mechanism 3z, a printing stage. An XYΘ table 3xyθ, a printing stage conveyor 8b, a carrier transport mechanism 20, a carry-in conveyor 8a, and a carry-out conveyor 8c are connected.

  The control unit 30 includes a mask recognition unit 31, a workpiece recognition unit 32, and a print processing unit 33 as internal processing functions. Further, the control unit 30 includes a storage unit 34 for storing information necessary for the control processing by these, and the storage unit 34 stores a mask reference mark and pattern hole position information on the mask plate 22. It has a portion 34a. The mask recognizing unit 31 detects the position of the mask reference mark and the pattern hole by recognizing the imaging result obtained by the second camera 19. The workpiece recognition unit 32 detects the position of the workpiece 10 placed on the carrier 9 by recognizing the imaging result obtained by the first camera 18.

  The print processing unit 33 controls each unit of the screen printing apparatus 1 to perform a process of executing screen printing on the plurality of workpieces 10 arranged on the carrier 9. The print processing unit 33 controls the backup elevating mechanism 5a, the printing stage elevating mechanism 3z, the printing stage XYΘ table 3xyθ, the printing stage conveyor 8b, the carrier conveying mechanism 20, the carry-in conveyor 8a, and the carry-out conveyor 8c. Is executed.

  In other words, the carrier 9 on which the work 10 to be printed is placed on the printing stage 2, the carrier 9 is supported by the carrier support unit including the printing stage conveyor 8 b, and the position of the work 10 placed on the carrier 9 on the mask plate 22 is detected. In addition, operations such as printing of the paste P onto the work 10 by the print head 13 and the print head moving mechanism 14 and carrying out of the carrier 9 after screen printing are performed.

  Next, a screen printing method executed by the screen printing apparatus 1 in the screen printing system of the first embodiment will be described with reference to FIG. First, in a preparatory stage prior to the execution of the screen printing operation, a mask recognition process is executed. Here, the second camera 19 is moved by the camera moving mechanism 16 below the mask plate 22, and the mask reference mark (not shown) of the mask plate 22 is imaged by the second camera 19. The image recognition result is recognized by the mask recognition unit 31 to detect the position of the mask plate 22 and the arrangement of the pattern holes. The detection result is stored in the mask pattern position storage unit 34a of the storage unit 34, thereby storing the mask position information required in the screen printing operation.

  When the screen printing operation is started, carrier loading is first executed (carrier loading step) (ST1). That is, as shown in FIG. 8A, the printing stage conveyor 8b is driven, and a plurality of workpieces 10 (here, workpieces 10 (1) to 10 (4)) are arranged corresponding to the respective first openings 9b. The carried carrier 9 is carried into the printing stage 2 from the upstream side. Then, the position of the carrier 9 is adjusted so that the engagement hole 9 c is positioned above the engagement portion 20 a of the carrier transport mechanism 20. At this time, the backup unit 6 and the mask plate support unit 7 are in a state of being lowered together with the backup support member 5.

  Subsequent steps are executed sequentially for individual workpieces 10 specified by the counter value K among the plurality of workpieces 10. First, the counter value K is set to K = 0 as an initial value (ST2). Next, when the work is started, the counter value K is incremented by 1, and K = K + 1 is set (ST3). In other words, the work 10 (1) is first the work target here.

  Next, carrier positioning by the carrier transport mechanism 20 is executed (carrier positioning step) (ST4). That is, as shown in FIG. 8B, the engaging pin 20c is projected from the engaging portion 20a and engaged with the engaging hole 9c. As a result, the carrier 9 is engaged by the engaging portion 20a. Next, as shown in FIG. 8C, the engaging portion moving shaft 20b is driven to move the engaging portion 20a (arrow b). As a result, the carrier 9 is positioned with respect to the backup unit 6 so that the first work target workpiece 10 (1) is positioned immediately above the backup unit 6. The carrier carry-in process and the carrier positioning process described above correspond to a carrier arrangement process in which the carrier 9 on which a plurality of workpieces 10 are placed is arranged on the printing stage 2.

  FIG. 9 shows the plane of the printing stage 2 after this carrier positioning step. That is, the carrier 9 in a state where the workpieces 10 (1) to 10 (4) are arranged corresponding to the plurality of first openings 9b is positioned by the engaging portion 20a of the carrier transport mechanism 20, and is first subjected to work. The workpiece 10 (1) is located immediately above the backup unit 6. In this state, the mask plate support 7 is located outside the carrier 9 and is located in the space between the pair of printing stage conveyors 8b.

  Next, the backup unit 6 is raised (backup process) (ST5). That is, the printing stage elevating mechanism 3z is driven to raise the backup support member 5 as shown in FIG. 10 (arrow c). As a result, the backup unit 6 moves up and down in a first opening 9 b formed through the carrier 9 in the vertical direction, and the backup unit 6 lifts the workpiece 10 (1) that is one of the plurality of workpieces 10. In this backup process, the mask plate support portion 7 is also raised together with the backup portion 6.

  In this ascending operation, the dimensions and back-ups of each part are set so that the height positions of the upper surface of the mask plate support portion 7 after the ascent, the upper surface of the workpiece 10 (1), and the upper edge portion of the conveyor guide portion 4b are the same height. The rising amount of the support member 5 is set. That is, the height of the upper surface 6 b of the backup portion 6 is set lower than the upper surface 7 b of the mask plate support portion 7 by the thickness t of the workpiece 10, and the amount of ascent of the backup support member 5 is the amount of the mask plate support portion 7. The upper surface 7b is set to coincide with the upper edge portion of the conveyor guide portion 4b.

  Next, workpiece (K) recognition for performing position recognition on the Kth workpiece 10 (K) (here, workpiece 10 (1)) is executed (work recognition step) (ST6). That is, as shown in FIG. 11, the camera moving mechanism 16 is driven to move the camera X-axis beam 15 and the camera mounting base 17, so that the first above the work 10 (1) lifted by the backup unit 6. The camera 18 is positioned and the work 10 (1) is imaged. The position of the workpiece 10 (1) is recognized by recognizing the imaging result by the workpiece recognition unit 32. And based on this position recognition result, the alignment operation which aligns the workpiece | work 10 (1) with the mask plate 22 is performed by driving the printing stage XY (theta) table 3xy (theta) (alignment process) (ST7). Thereby, the workpiece 10 (1) to be printed is aligned with the pattern hole forming region 22 a of the mask plate 22.

  Next, the printing stage 2 is raised (arrow d) and brought into contact with the lower surface of the mask plate 22 (mask plate contacting step) (ST8). Thereby, as shown in FIG. 12, the backup part 6 and the mask plate support part 7 are lifted together with the backup support member 5. As a result, the workpiece 10 (1) to be printed lifted by the backup unit 6 is brought into contact with the pattern hole forming region 22 a of the mask plate 22 from the lower surface, and the print head 13 can start the printing process. .

  At the same time, the mask plate support part 7 comes into contact with the lower surface of the mask plate 22, and at least during the printing process, a mask plate support process for supporting the lower surface of the mask plate 22 by the mask plate support part 7 is started (mask plate support process). (Start) (ST8). In this mask plate support step, the mask plate support portion 7 supports the lower surface of the mask plate 22 that protrudes outward from the carrier 9.

  Note that (ST6) to (ST8) are mask plate arrangements in which the work plate 10 lifted in the backup process and the mask plate 22 formed with the pattern holes for printing are aligned and the mask plate 22 is arranged above the work 10. Corresponds to the process. In this state, the print head 13 is moved to print the paste on the workpiece 10 (1) (printing process) (ST9).

  When the printing process is completed, the printing stage 2 is lowered to separate the workpiece 10 (1) from the mask plate 22 (plate separation process) (ST10). That is, the printing stage moving mechanism 3 is driven to lower the printing stage 2 as shown in FIG. 13 (arrow e). As a result, plate separation is performed to separate the printing surface on the upper surface of the workpiece 10 (1) from the lower surface of the mask plate 22. By this separation of the plate, the support of the mask plate 22 by the mask plate support portion 7 ends (the mask plate support process ends).

  After the separation of the plate, the backup lifting mechanism 5a is driven to lower the backup support member 5 (arrow f), and the backup unit 6 and the mask plate support unit 7 are lowered on the printing stage 2 (ST11). Thereby, the work 10 (1) after the printing process is placed on the carrier 9 supported by the printing stage conveyor 8b which is a carrier support part (work placing process). Thereby, the screen printing for the workpiece 10 (1) among the plurality of workpieces 10 arranged on one carrier 9 is completed.

  Thereafter, it is determined whether or not the screen printing process has been completed for all the workpieces 10 (ST12). In the example shown here, since the process is completed only for the first workpiece 10 (1), it is determined that there is no process, and the process returns to (ST3) and the subsequent processes are repeated. That is, the counter value K is incremented by one in (ST3), and the carrier positioning step (ST4) is executed for the workpiece 10 (2).

  First, as shown in FIG. 14, the engaging portion 20 a engaged with the carrier 9 is moved by the engaging portion moving shaft 20 b, and the carrier 9 is placed so that the workpiece 10 (2) is located immediately above the backup portion 6. Move (arrow g). And the process of (ST5)-(ST11) is performed by making workpiece | work 10 (2) into object. Thereafter, the work 10 (3) and the work 10 (4) are also returned to (ST3), and the same processing steps are repeatedly executed while the counter value K is sequentially advanced. As a result, as shown in FIG. 15A, the paste P is printed on all of the workpieces 10 (1) to 10 (2) arranged on the carrier 9.

  Next, prior to carrying out the carrier 9, as shown in FIG. 15B, the engagement of the carrier 9 by the engaging portion 20a is released. That is, the engagement pin 20c (see FIG. 8) fitted in the engagement hole 9c of the carrier 9 is released from the engagement hole 9c. As a result, the carrier 9 can be moved on the printing stage 2 by the printing stage conveyor 8b.

  If it is determined in (ST12) that the processing has been completed for all the workpieces 10, the carrier 9 on which the printed workpieces 10 are arranged is carried out (carrier carrying-out process). That is, as shown in FIG. 15 (c), the printing stage conveyor 8b is driven to carry out the carrier 9 on which the printed workpieces 10 (1) to 10 (4) are arranged downstream (arrow h). .

  Thereby, the screen printing process for a plurality of works 10 arranged on one carrier 9 is completed. In this screen printing process, a backup process, an alignment process, a printing process, a mask plate support process, and a workpiece placement process are sequentially performed on the plurality of workpieces 10 to print the paste P on the plurality of workpieces 10. It has become.

  Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 16 shows a carrier 9A used in the screen printing system of the second embodiment. Similarly to the carrier 9 shown in FIG. 5 in the first embodiment, the carrier 9A has a plurality of workpieces 10 and is supported by a printing stage conveyor 8b, which is a carrier support portion, from a pair of opposite edges from below. Used. The workpiece 10 is the same as the workpiece 10 in the first embodiment, and a plurality of connection electrodes 10a and a pair of position recognition workpiece recognition marks 10m are formed on the upper surface.

  On the upper surface of the carrier 9A, a plurality of workpiece storage recesses 9a for arranging the workpiece 10 are formed in a predetermined arrangement. A first opening 9b formed through the carrier 9A in the vertical direction is provided at the bottom of the work storage recess 9a. The carrier 9A is formed with a plurality of second openings 9d penetrating the carrier 9A in the vertical direction so as to sandwich the respective work storage recesses 9a from both sides.

  The carrier 9A having the above-described configuration is used in combination with the printing stage 2A shown in FIG. In FIG. 17A, the printing stage 2A has a backup support member 5A that is lifted and lowered by a backup lift mechanism 5a in the same manner as the backup support member 5 in the first embodiment. At the center of the backup support member 5A, a backup unit 6A is provided corresponding to the position and planar shape of the first opening 9b in the carrier 9A supported by the printing stage conveyor 8b.

  Further, at both ends of the backup support member 5A, mask plate support portions 7A corresponding to the position and planar shape of the second opening 9d in the carrier 9A supported by the printing stage conveyor 8b are provided. The backup unit 6A and the mask plate support unit 7A are moved up and down by a backup lift mechanism 5a that is a common lift mechanism. Here, the height difference ΔH is larger than the thickness t of the workpiece 10 so that the upper surface 6b of the backup portion 6 is positioned lower than the upper surface 7b of the mask plate support portion 7A by the thickness t of the workpiece 10. The dimension of each part is set so that it may become.

  FIG. 17B shows a state in which the backup lifting mechanism 5a is driven in the printing stage 2A to raise the backup support member 5A (arrow i), and the backup portion 6A and the mask plate support portion 7A are raised. . That is, the backup unit 6A lifts the upper surface 6b in contact with one of the plurality of workpieces 10 arranged on the carrier 9A through the first opening 9b formed through the carrier 9A in the vertical direction.

  17C, the printing stage lifting mechanism 3z (see FIG. 2) is driven to raise the printing stage 2A (arrow j), and the work 10 lifted by the backup unit 6 is brought into contact with the mask plate 22 on the lower surface. It shows the state that was made to. At this time, the mask plate support portions 7A disposed on both sides of the backup portion 6A are also lifted, and support the lower surface of the mask plate 22 through the second opening 9d formed through the carrier 9A in the vertical direction.

  That is, in the screen printing method according to the second embodiment, at least in the mask plate supporting process for supporting the lower surface of the mask plate 22 during the printing process, the screen 9 is moved up and down in the second opening 9d formed through the carrier 9A in the vertical direction. The lower surface of the mask plate 22 is supported by the mask plate support portion 7A. Thus, in the screen printing operation in which the squeegee 13b of the print head 13 is moved in the squeezing direction on the upper surface of the mask plate 22, the lower surface of the mask plate 22 is reliably supported by the upper surface 7b of the mask plate support portion 7A. Thereby, the same effect as the effect demonstrated in Embodiment 1 is acquired.

  In the above configuration, the upper surfaces of the pair of transport belts of the printing stage conveyor 8b are a pair of carrier support surfaces that support a pair of opposed edges of the carrier 9A from below. And the mask plate support part 7A which contacts and supports the lower surface of the mask plate 22 is arranged in a space sandwiched between the pair of carrier support surfaces. Such a configuration is common to the carriers 9B, 9C, and 9D and mask plate support portions 7B, 7C, and 7D in the third, fourth, and fifth embodiments described below.

  Next, a third embodiment of the present invention will be described with reference to FIG. 18, FIG. 19, and FIG. FIG. 18 shows a carrier 9B used in the screen printing system of the third embodiment. Similarly to the carrier 9 shown in FIG. 5 in the first embodiment, the carrier 9B is configured such that a plurality of workpieces 10 are arranged and a pair of opposed edges are supported from below by a printing stage conveyor 8b that is a carrier support unit. Used. The workpiece 10 is the same as the workpiece 10 in the first embodiment, and a plurality of connection electrodes 10a and a pair of position recognition workpiece recognition marks 10m are formed on the upper surface.

  On the upper surface of the carrier 9B, a plurality of rectangular workpiece storage recesses 9a for arranging the workpiece 10 similar to the workpiece 10 in the first embodiment are formed in a predetermined arrangement. The carrier 9B is formed with a narrow rectangular frame-shaped first opening 9b * in a direction perpendicular to the longitudinal direction of the workpiece storage recess 9a (longitudinal direction of the carrier 9B) so as to intersect with each workpiece storage recess 9a. ing. In a state where the workpiece 10 is accommodated in the workpiece accommodating recess 9a and the workpiece 10 is disposed on the carrier 9B, both ends of the first opening 9b * are partially exposed on the upper surface of the carrier 9B on both sides of the workpiece 10. Become.

  As shown in FIG. 19, the carrier 9B is used in combination with a printing stage 2B including a backup unit 6B configured to function as a mask plate support unit 7B that partially supports the lower surface of the mask plate 22 to support it. . That is, in FIG. 20A, the printing stage 2B has a backup unit 6B that is lifted and lowered by the backup lifting mechanism 5a in the same manner as the backup support member 5 in the first embodiment. The backup unit 6B has a shape corresponding to the position and planar shape of the first opening 9b * in the carrier 9B supported by the printing stage conveyor 8b.

  Mask plate support portions 7B are formed so as to protrude upward from the upper surface 6b at both end portions of the upper surface 6b of the backup portion 6B. The mask plate support portion 7B is formed in a shape corresponding to the position and the planar shape of the first opening 9b * that is partially exposed on both sides of the work 10 in a state where the work 10 is arranged. Here, the upper surface 6b of the backup unit 6B is positioned lower than the upper surface 7b of the mask plate support 7B by at least the thickness t of the workpiece 10, that is, the height difference ΔH between the upper surface 6b and the upper surface 7b is the workpiece. The dimension of each part is set so that it may become larger than 10 thickness t.

  FIG. 20B shows a state in which the backup lifting mechanism 5a is driven to raise the backup unit 6B in the printing stage 2B (arrow k). In this ascending operation, the backup unit 6B lifts the upper surface 6b in contact with one of the plurality of workpieces 10 arranged in the carrier 9B through a first opening 9b * formed penetrating the carrier 9B in the vertical direction.

  20C, the printing stage elevating mechanism 3z (see FIG. 2) is driven to raise the printing stage 2B (arrow m), and the work 10 lifted by the backup unit 6B comes into contact with the lower surface of the mask plate 22. It shows the state that was made to. At this time, the mask plate support portions 7B provided on both sides of the backup portion 6B also rise, and support the lower surface of the mask plate 22 through the first openings 9b * formed through the carrier 9B in the vertical direction.

  That is, in the third embodiment, a part of the backup portion 6B protrudes upward and functions as the mask plate support portion 7B. In the screen printing method according to the third embodiment, at least in the mask plate supporting step for supporting the lower surface of the mask plate 22 during the printing process, the lower surface of the mask plate 22 is supported by using a part of the backup unit 6B. ing. Thus, in the screen printing operation in which the squeegee 13b of the print head 13 is moved in the squeezing direction on the upper surface of the mask plate 22, the lower surface of the mask plate 22 is reliably supported by the upper surface 7b of the mask plate support portion 7B. Thereby, the same effect as the effect demonstrated in Embodiment 1 is acquired.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 21 shows a carrier 9C used in the screen printing system of the fourth embodiment. Similarly to the carrier 9 shown in FIG. 5 in the first embodiment, the carrier 9C is configured such that a plurality of workpieces 10 are arranged and a pair of opposed edges are supported from below by a printing stage conveyor 8b that is a carrier support unit. Used. The workpiece 10 is the same as the workpiece 10 in the first embodiment.

  On the upper surface of the carrier 9C, a plurality of rectangular workpiece storage recesses 9a (see FIG. 22) for arranging the same workpieces 10 as in the first and second embodiments are formed in a predetermined arrangement. A first opening 9b formed through the carrier 9 in the vertical direction is provided at the bottom of the workpiece housing recess 9a (see FIG. 22). The carrier 9C is provided with a plurality of mask plate support portions 7C projecting upward from the upper surface of the carrier 9C, with the respective work storage recesses 9a sandwiched from both sides. That is, in the fourth embodiment, the mask plate support portion is provided in the form of a plurality of protrusions arranged on the carrier 9C.

  The carrier 9C is used in combination with the printing stage 2C provided with the backup unit 6C having the configuration shown in FIG. That is, in FIG. 22A, the printing stage 2C has a backup unit 6C that is lifted and lowered by the backup lifting mechanism 5a, like the backup support member 5 in the first embodiment. The backup unit 6C has a shape corresponding to the position and planar shape of the first opening 9b in the carrier 9C supported by the printing stage conveyor 8b.

  FIG. 22B shows a state in which the backup lift mechanism 5a is driven to raise the backup unit 6C in the printing stage 2C (arrow n). That is, the backup unit 6C lifts the upper surface 6b in contact with one of the plurality of workpieces 10 arranged in the carrier 9C through the first opening 9b formed through the carrier 9C in the vertical direction. At this time, the rising amount of the backup unit 6C is controlled so that the height of the upper surface of the lifted work 10 is the same as the height of the upper surface 7b of the mask plate support 7C.

  In FIG. 22C, the printing stage elevating mechanism 3z (see FIG. 2) is driven to raise the printing stage 2C (arrow o), and the work 10 lifted by the backup unit 6C is brought into contact with the lower surface of the mask plate 22 It shows the state that was made to. At this time, the mask plate support portions 7C provided on both sides of the backup portion 6C are also raised, and the lower surface of the mask plate 22 is supported by the upper surface 7b of the mask plate support portion 7C.

  That is, in the fourth embodiment, the mask plate support portion 7C is arranged on the carrier 9C. In the screen printing method according to the fourth embodiment, at least in the mask plate supporting process for supporting the lower surface of the mask plate 22 during the printing process, the mask plate supporting portion 7C disposed on the carrier 9C is applied to the lower surface of the mask plate 22. I try to contact them. Thereby, in the screen printing operation in which the squeegee 13b of the print head 13 is moved in the squeezing direction on the upper surface of the mask plate 22, the lower surface of the mask plate 22 is reliably supported by the upper surface 7b of the mask plate support portion 7C. Thereby, the same effect as the effect demonstrated in Embodiment 1 is acquired.

  Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 23A shows a carrier 9D used in the screen printing system of the fifth embodiment. Similarly to the carrier 9 shown in FIG. 5 in the first embodiment, the carrier 9D has a plurality of workpieces 10 disposed thereon and is supported by a printing stage conveyor 8b serving as a carrier support portion from a pair of opposite edges from below. Used. The workpiece 10 is the same as the workpiece 10 in the first embodiment.

  The carrier 9D is formed with a plurality of rectangular work storage recesses 9a (see FIG. 22) in a predetermined arrangement for placing the same work 10 as the work 10 in the first embodiment. Unlike the carriers 9, 9A, 9B, and 9C in the other embodiments, the carrier 9D is a substantially rectangular block-shaped member having a predetermined thickness. A first opening 9b formed through the carrier 9D in the up and down direction is provided at the bottom of the workpiece housing recess 9a (see FIG. 22).

  The periphery of the work storage recess 9a on the upper surface of the carrier 9D is a mask plate support portion 7D that contacts and supports the lower surface of the mask plate 22. That is, in the fifth embodiment, the carrier 9D has a workpiece storage recess 9a that is a recess for storing the workpiece 10, and the mask plate support 7D is the upper surface of the carrier 9D around the workpiece storage recess 9a.

  The carrier 9D is used in combination with a printing stage 2D provided with a backup unit 6D having the configuration shown in FIG. That is, in FIG. 23A, the printing stage 2D has a backup unit 6D that is lifted and lowered by the backup lifting mechanism 5a, like the backup support member 5 in the first embodiment. The backup unit 6D has a shape corresponding to the position and planar shape of the first opening 9b in the carrier 9D supported by the printing stage conveyor 8b.

  FIG. 23B shows a state in which the backup lifting mechanism 5a is driven to raise the backup unit 6D in the printing stage 2D (arrow p). That is, the backup unit 6D lifts the upper surface 6b in contact with one of the plurality of workpieces 10 arranged in the carrier 9D through the first opening 9b formed through the carrier 9D in the vertical direction. At this time, the rising amount of the backup unit 6D is controlled so that the height of the upper surface of the lifted work 10 is the same as the height of the mask plate support 7D.

  23C, the printing stage elevating mechanism 3z (see FIG. 2) is driven to raise the printing stage 2C (arrow q), and the work 10 lifted by the backup unit 6D is brought into contact with the lower surface of the mask plate 22. It shows the state that was made to. At this time, the carrier 9D also rises, and the lower surface of the mask plate 22 is supported by the mask plate support portion 7D on the upper surface of the carrier 9D.

  That is, in the fifth embodiment, the mask plate support 7D is arranged on the carrier 9D. In the screen printing method according to the fifth embodiment, at least in the mask plate support process for supporting the lower surface of the mask plate 22 during the printing process, the mask plate support portion 7D disposed on the carrier 9D is disposed on the lower surface of the mask plate 22. It is made to contact. Thereby, in the screen printing operation in which the squeegee 13b of the print head 13 is moved in the squeezing direction on the upper surface of the mask plate 22, the lower surface of the mask plate 22 is reliably supported by the mask plate support portion 7D. Thereby, the same effect as the effect demonstrated in Embodiment 1 is acquired.

  As described above, in the screen printing system shown in the present embodiment, the printing stage conveyor 8b that supports the carrier 9 on which the plurality of works 10 are arranged below the mask plate 22 and the plurality of works 10 from the carrier 9. A back-up unit 6 that lifts one of them and abuts the lower surface of the mask plate; an alignment mechanism that relatively moves the back-up unit 6 and the mask plate 22; In the configuration including the print head 13 that prints the paste on the workpiece 10 in contact with the lower surface, at least the lower surface of the mask plate 22 is supported by the mask plate support portion 7 when the print head 13 prints on the workpiece 10. ing.

  Thereby, the bending of the mask plate 22 due to the printing pressure of the print head 13 acting on the mask plate 22 that is not received is reduced. For this reason, it is possible to suppress printing defects caused by the edge of the workpiece 10 hitting the mask plate 22 and the like, and it is possible to improve productivity while preventing printing defects in the multi-sheet taking system.

  INDUSTRIAL APPLICABILITY The screen printing system and the screen printing method of the present invention have an effect that productivity can be improved while preventing printing defects in the multi-sheet taking method, and in the screen printing field for printing paste on a workpiece such as a substrate. Useful.

DESCRIPTION OF SYMBOLS 1 Screen printing apparatus 2, 2A, 2B, 2C, 2D Printing stage 3 Printing stage moving mechanism 6, 6A, 6B, 6C, 6D Backup part 7, 7A, 7B, 7C, 7D Mask plate support part 8b Printing stage conveyor (carrier Support part)
9, 9A, 9B, 9C, 9D Carrier 10 Work 13 Print head 22 Mask plate

Claims (17)

A mask plate having a pattern hole for printing;
A carrier with multiple workpieces,
A carrier support for supporting the carrier below the mask plate;
A backup unit that lifts one of the plurality of workpieces from the carrier supported by the carrier support unit and makes contact with the lower surface of the mask plate;
An alignment mechanism for relatively moving the backup unit and the mask plate in order to align the workpiece lifted by the backup unit and the mask plate;
A print head for printing a paste on a work contacting the lower surface of the mask plate through the pattern hole from the upper surface of the mask plate;
A screen printing system comprising: at least a mask plate support portion that supports a lower surface of the mask plate when the print head performs printing on the workpiece.   The screen printing system according to claim 1, wherein the backup unit lifts one of the plurality of workpieces through a first opening formed through the carrier in a vertical direction.   The carrier support portion has a pair of carrier support surfaces that support two opposite edges of the carrier from below, and the mask plate support portion is disposed in a space sandwiched between the carrier support surfaces. The screen printing system according to claim 2.   The screen printing system according to claim 3, wherein the mask plate support portion is disposed in a space outside the carrier supported by the carrier support portion.   The screen printing system according to claim 3, wherein the mask plate support part supports a lower surface of the mask plate through a second opening formed through the carrier in a vertical direction.   The screen printing system according to claim 3, wherein the backup unit and the mask plate support unit are lifted and lowered by a common lifting mechanism.   The screen printing system according to claim 2, wherein a part of the backup unit is the mask plate support unit.   8. The screen printing system according to claim 6, wherein an upper surface of the backup unit is positioned lower than an upper surface of the mask plate support unit by at least the thickness of the workpiece.   The screen printing system according to claim 2, wherein the mask plate support is disposed on the carrier.   The screen printing system according to claim 9, wherein the mask plate support part is a plurality of protrusions arranged on the carrier.   The screen printing system according to claim 9, wherein the carrier has a concave portion that accommodates a workpiece, and the mask plate support portion is an upper surface of the carrier around the concave portion. A carrier placement step of placing a carrier with a plurality of workpieces on a printing stage;
A backup step of pushing up and lifting one of the plurality of workpieces from the carrier arranged on the printing stage;
A mask plate placement step of positioning the mask plate above the workpiece by aligning the work plate lifted in the backup step and the mask plate on which a pattern hole for printing is formed;
A printing step of printing a paste on the workpiece through the pattern hole by moving the print head against the upper surface of the mask plate; and
A mask plate support step for supporting the lower surface of the mask plate during at least the printing step;
A workpiece placing step of placing the workpiece on which the printing step has been completed on the carrier supported by the carrier support portion, and
Printing the paste on the plurality of workpieces by sequentially executing the backup step, the alignment step of the mask plate placement step, the printing step, the mask plate support step, and the workpiece placement step for a plurality of workpieces, Screen printing method.   13. The screen printing method according to claim 12, wherein, in the backup step, one of the plurality of workpieces is lifted by a backup unit that moves up and down in a first opening formed through the carrier in the vertical direction.   The screen printing method according to claim 13, wherein, in the mask plate supporting step, a lower surface of the mask plate that protrudes outward from the carrier is supported.   14. The screen printing method according to claim 13, wherein, in the mask plate supporting step, the lower surface of the mask plate is supported by a mask plate supporting portion that moves up and down in a second opening formed through the carrier in a vertical direction.   The screen printing method according to claim 13, wherein, in the mask plate supporting step, a lower surface of the mask plate is supported using a part of the backup unit.   The screen printing method according to claim 11, wherein, in the mask plate supporting step, a mask plate supporting portion disposed on the carrier is brought into contact with a lower surface of the mask plate.

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