JP2012061607A - Screen printing apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screen printing apparatus and method that can prevent defects in printing quality from occurring due to adhesiveness of a substrate.SOLUTION: Screen printing is applied to the substrate 9 clamped by a clamp member 8a. In the screen printing, the clamp state-controlling process for adjusting relative height of upper surfaces of the substrate 9 and clamp member 8a in a substrate-clamped state includes: a step of calculating the height HCM of the clamp member and the height HBM of the upper surface of the substrate, by measuring the heights of a plurality of first height-measuring points set in the clamp member 8a and a plurality of second height-measuring points set in the upper surface of the substrate 9, respectively; a step of controlling the behavior of a substrate underside-support unit 6 based on the calculated heights HCM and HBM; and adjusting the relative height of the upper surfaces of the substrate 9 and clamp member 8a.

Description

  The present invention relates to a screen printing apparatus and a screen printing method for printing paste such as cream solder on a substrate.

  Solder bonding is often used as a bonding method for mounting electronic components on a substrate. In this method, a paste such as cream solder, which is a solder bonding material, is supplied to the electrodes of the substrate prior to the solder bonding. As this solder supply method, screen printing in which cream solder is printed on a substrate through pattern holes provided in a mask plate is widely used (see, for example, Patent Document 1). In the screen printing operation, the substrate to be printed is sandwiched from both sides in the horizontal direction by the clamp member and the position is fixed, and the substrate is brought into contact with the lower surface of the mask plate while being supported from the lower surface side by the receiving member.

  In order to obtain a high-quality printing result in screen printing, it is necessary to bring the printed surface of the substrate into close contact with the mask plate with high accuracy in squeezing by sliding the squeegee on the mask plate. That is, the relative position in the height direction of the substrate and the clamp member is correctly set so that the upper surface of the substrate and the upper surface of the clamp member that sandwiches the substrate are located in the same plane as much as possible. For this purpose, the prior art disclosed in Patent Document 1 describes an example in which the height position of the upper surface of the substrate and the clamp member (stage part) is measured by a distance sensor such as a laser sensor.

JP-A-9-76455

  In recent years, the form of a mounting board on which electronic components are mounted has also been reduced in size and diversified, and various forms of boards have been subjected to mounting work in the component mounting process. For example, when manufacturing a small board, a multi-sided board method in which a plurality of small child boards are made in one parent board for improving production efficiency is adopted. It is cut out in advance except for a bridge portion necessary for connecting the sub boards. For this reason, the entire parent substrate often exhibits a complicated warp deformation state as compared with a conventional single substrate, and in such a clamped state where such a parent substrate is sandwiched and fixed by a clamp member from the horizontal direction. The difference between the upper surface height of the clamp member and the parent substrate is likely to occur.

  When the parent substrate in such a clamped state is brought into contact with the lower surface of the mask plate, a gap is generated between the mask plate and the mask plate due to the height difference from the clamp member, and the print quality is reduced. Causes a defect. Further, the quality defect due to such adhesion with the mask plate similarly occurs due to variations in substrate thickness, erroneous input of substrate thickness data, and the like. As described above, the conventional screen printing apparatus has a problem that it is unavoidable to cause a printing quality defect due to the adhesion between the substrate and the mask plate.

  Therefore, an object of the present invention is to provide a screen printing apparatus and a screen printing method that can prevent a print quality defect caused by the adhesion between the substrate and the mask plate.

  In the screen printing apparatus of the present invention, the substrate is brought into contact with the lower surface of the mask plate in which the pattern holes are formed, and the squeegee is slid on the upper surface of the mask plate to which the paste is supplied, thereby causing the substrate to pass through the pattern holes. A screen printing apparatus for printing a paste, wherein the substrate receiving portion is disposed so as to be movable up and down from below with respect to the mask plate and holds the substrate at a printing position on the lower surface side of the mask plate; and A substrate transport unit that transports a substrate in the first direction by transporting the substrate in the first direction and unloads the printed substrate from the substrate support portion; and the substrate received by the substrate support portion A pair of clamp members sandwiched from a second direction orthogonal to the first direction; an upper surface of the pair of clamp members disposed in a horizontal plane; and the substrate A height measuring means for measuring the height of the upper surface as a measurement target, and the height measuring means are sequentially moved to execute height measurement, and based on the height measurement result by the height measuring means, A clamp state control unit that adjusts a relative height between the upper surface of the substrate and the upper surface of the clamp member in a clamped state in which the substrate is sandwiched between clamp members by controlling a receiving portion; The portion includes a plurality of first height measurement points set to include at least two points at both ends of each of the pair of clamp members, and a plurality of second heights set in advance in a regular arrangement with respect to the upper surface of the substrate. A measurement execution unit that executes a height measurement operation on a plurality of height measurement points, and an average value of height measurement values obtained on the plurality of first height measurement points By calculating the height of the clamp member by obtaining the data and processing the height measurement values obtained for the plurality of second height measurement points according to a predetermined statistical processing algorithm, A height calculation processing unit that calculates an average value of a plurality of height measurement values excluding a singular point that is not recognized as an upper surface height measurement value, and calculates the substrate upper surface height, and the calculated clamp member height And a height adjusting unit that adjusts a relative height between the upper surface of the substrate and the upper surface of the clamp member by controlling the substrate lower receiving portion based on the height of the upper surface of the substrate.

  The screen printing method of the present invention includes a substrate receiving portion that is disposed so as to be movable up and down from below with respect to the mask plate and holds the substrate at a printing position on the lower surface side of the mask plate, and the substrate in the first direction. A substrate carrying unit that carries the substrate into the substrate receiving unit and unloads the printed substrate from the substrate receiving unit, and the substrate received by the substrate receiving unit is orthogonal to the first direction. A pair of clamp members sandwiched from the second direction, and a height measuring unit that is disposed so as to be movable in a horizontal plane and that measures the height of the upper surface of the pair of clamp members and the upper surface of the substrate. The substrate is brought into contact with the lower surface of the mask plate in which pattern holes are formed, and the squeegee is slid on the upper surface of the mask plate to which the paste is supplied. This is a screen printing method for printing a paste on the substrate through the pattern hole, wherein the height measurement means is sequentially moved to perform height measurement, and the height measurement result by the height measurement means A clamping state control step of adjusting a relative height between the upper surface of the substrate and the upper surface of the clamping member in a substrate clamping state by controlling the substrate lower receiving portion based on the clamping state control step. Each of the pair of clamp members includes a plurality of first height measurement points set to include at least two points at both ends, and a plurality of second heights set in advance in a regular arrangement with respect to the upper surface of the substrate. A measurement execution step for executing a height measurement operation on a height measurement point, and a height meter obtained on the plurality of first height measurement points The clamp member height is calculated by obtaining an average value, and the height measurement values obtained for the plurality of second height measurement points are subjected to data processing according to a predetermined statistical processing algorithm. A height calculation processing step of calculating an average value of a plurality of height measurement values excluding singular points that are not recognized as a height measurement value of the upper surface of the substrate, and calculating the substrate upper surface height; A height adjustment step of adjusting a relative height between the upper surface of the substrate and the upper surface of the clamp member by controlling the substrate receiving portion based on the height of the clamp member and the height of the upper surface of the substrate.

  According to the present invention, in the clamp state control step of adjusting the relative height between the upper surface of the substrate and the upper surface of the clamp member in the substrate clamp state, the plurality of first height measurement points set on the clamp member and the substrate A height measurement operation is executed for a plurality of second height measurement points set for the upper surface to calculate the clamp member height and the substrate upper surface height, and the calculated clamp member height and substrate upper surface height are calculated. Based on the above, by controlling the substrate receiving portion and adjusting the relative height between the upper surface of the substrate and the upper surface of the clamp member, print quality defects caused by the adhesion between the substrate and the mask plate can be reduced. Can be prevented.

1 is a front view of a screen printing apparatus according to an embodiment of the present invention. The side view of the screen printing apparatus of one embodiment of this invention The top view of the screen printing apparatus of one embodiment of this invention The top view of the board | substrate used as the printing object of the screen printing apparatus of one embodiment of this invention The block diagram which shows the structure of the control system of the screen printing apparatus of one embodiment of this invention Explanatory drawing of clamp member height measurement in the screen printing method of one embodiment of the present invention Explanatory drawing of the board | substrate upper surface height measurement in the screen printing method of one embodiment of this invention The flowchart which shows the clamp state control processing in the screen printing method of one embodiment of this invention Operation explanatory diagram of a screen printing apparatus according to an embodiment of the present invention Explanatory drawing of relative height adjustment of the upper surface of a board | substrate and the upper surface of a clamp member in the screen printing method of one embodiment of this invention

  Next, embodiments of the present invention will be described with reference to the drawings. First, the structure of the screen printing apparatus will be described with reference to FIGS. This screen printing device prints the paste on the substrate through the pattern holes by bringing the substrate into contact with the lower surface of the mask plate on which the pattern holes are formed and sliding the squeegee on the upper surface of the mask plate to which the paste is supplied. It has the function to do.

  1 and 2, the substrate positioning unit 1 includes a θ-axis table 4 and a Z-axis table 5 stacked on a moving table made up of a Y-axis table 2 and an X-axis table 3, and further a substrate receiving unit thereon. 6 is provided. The substrate receiving portion 6 receives and holds the substrate 9 to be printed from the lower surface side, and drives the Z-axis table 5 so that the substrate receiving portion 6 moves up and down together with the held substrate 9. In other words, the substrate lower receiving portion 6 is disposed so as to be movable up and down with respect to the mask plate 12 described below, and has a function of receiving the substrate 9 and holding it at the printing position on the lower surface side of the mask plate 12. . Further, by driving the Y-axis table 2, the X-axis table 3, and the θ-axis table 4, the substrate 9 held by the substrate receiving portion 6 is moved in a horizontal plane and aligned with the mask plate 12 in the horizontal direction. can do.

  Above the substrate positioning unit 1, there is horizontally disposed a substrate transport unit 7 in which a pair of carry-in conveyor 7a, print conveyor 7b, and carry-out conveyor 7c are arranged in series. As shown in FIG. 3, the carry-in conveyor 7a conveys the substrate 9 received from the upstream side to the substrate positioning unit 1 in the X direction (first direction) and delivers it to the printing conveyor 7b. Here, the substrate 9 is a multi-sided substrate in which a plurality of unit substrates 9a are formed in the same substrate. That is, as shown in FIG. 4, a plurality of (here, three) unit substrates 9 a are formed on the substrate 9.

  Each unit substrate 9a is held by a connecting bridge 9c extending from the outer frame portion 9b constituting the outer edge portion of the substrate 9 to each unit substrate 9a to form a single substrate 9 as a whole. ing. The connection bridge 9c is provided only in a range necessary for holding the unit substrate 9a, and a range in which the connection bridge 9c is not provided between the outer frame portion 9b and each unit substrate 9a is a plate portion of the substrate 9. This is a notch portion 9d that does not exist. With such a configuration, the substrate 9 as a whole has the characteristics that bending rigidity is smaller than that of a normal single substrate and warpage deformation is likely to occur.

  The printing conveyor 7b carries the delivered substrate 9 into a printing work position by the screen printing unit 10 described below. And the board | substrate 9 after printing by the screen printing part 10 mentioned later in the board | substrate positioning part 1 is similarly carried out downstream by the carrying-out conveyor 7c. That is, the substrate transport unit 7 transports the substrate 9 in the X direction, thereby loading the substrate 9 into the substrate positioning unit 1 and unloading the printed substrate 9 from the substrate positioning unit 1. The print conveyor 7b is provided with a clamp mechanism 8 configured to open and close a pair of clamp members 8a by an open / close drive mechanism (not shown).

  The substrate 9 carried into the printing work position is sandwiched by the pair of clamp members 8a from the Y direction (second direction) orthogonal to the X direction, thereby fixing the horizontal position of the substrate 9 during the printing work. The Further, the printing conveyor 7b can be moved up and down by a transport unit lifting mechanism (not shown), and the substrate 9 clamped by the clamp member 8a can be brought into contact with the lower surface of the mask plate 12 during a printing operation.

  Here, since the substrate 9 is a multi-sided substrate having a plurality of unit substrates 9a as described above and has a characteristic that warp deformation is likely to occur, the substrate 9 is clamped by the clamp member 8a while being warped. As a result, when the substrate 9 is in contact with the mask plate 12, the substrate 9 does not adhere well to the lower surface of the mask plate 12, and there is a possibility that the screen printing operation may be performed with a gap left. is there. For this reason, in the present embodiment, the adhesion between the substrate 9 and the mask plate 12 is improved by a method described later.

  A screen printing unit 10 is disposed above the substrate positioning unit 1. The screen printing unit 10 has a configuration in which a squeegee unit 13 is disposed above a mask plate 12 that is extended on a rectangular holder 11 and provided with a plurality of pattern holes (not shown). As shown in FIG. 2, the squeegee unit 13 has a configuration in which a squeegee 16 is vertically moved by two squeegee lifting mechanisms 15 vertically disposed on a horizontal base 14, and a squeegee moving mechanism (not shown) is used. , Reciprocates in the Y direction.

  In the screen printing operation, first, the substrate 9 is brought into contact with the lower surface of the mask plate 12, and the cream solder 17 is supplied onto the mask plate 12. Then, one of the two squeegees 16 of the squeegee unit 13 is brought into contact with the surface of the mask plate 12 and is slid, whereby the printed surface of the substrate 9 is cream soldered via a pattern hole provided in the mask plate 12. 17 is printed.

  A three-dimensional measurement sensor 20 is provided above the mask plate 12. As shown in FIG. 3, the three-dimensional measurement sensor 20 is horizontally moved in the XY directions by the X-axis table 21 and the Y-axis table 22. The X-axis table 21 and the Y-axis table 22 are sensor moving means for moving the three-dimensional measurement sensor 20. The substrate positioning unit 1 is moved in the Y direction from below the mask plate 12 by the Y-axis table 2 (arrow a) so that the held substrate 9 can be moved to the height measurement position by the three-dimensional measurement sensor 20. (See FIG. 9). In this state, the height of the clamp member 8a and the height of the substrate 9 can be measured by sequentially moving the three-dimensional measurement sensor 20 above a plurality of measurement target positions set on the clamp member 8a and the substrate 9. it can. In the present embodiment, the relative height between the upper surface of the clamp member 8a and the upper surface of the substrate 9 is adjusted based on these measurement results.

  Next, the configuration of the control system will be described with reference to FIG. The control unit 30 has a CPU function, and executes various operation / processing programs stored in the storage unit 31 to control and control each unit described below to perform screen printing work by a screen printing apparatus. Perform operations and various control processes. In addition to the above-described various operation / processing programs and various data used for these processes, the storage unit 31 stores the upper surface of the substrate 9 and the upper surface of the clamp member 8a when the substrate 9 is received by the substrate receiving unit 6. The base height data 31a referred to for adjusting the relative height is stored. Here, based on the thickness data of the target substrate 9, the appropriate height of the substrate receiving portion 6 for bringing the substrate 9 received by the substrate receiving portion 6 into close contact with the mask plate 12 at the printing work position is as follows. It is stored as under height data.

  The mechanism driving unit 32 is controlled by the control unit 30 to drive each unit of the substrate transport unit 7, the substrate positioning unit 1, the clamp mechanism 8, and the screen printing unit 10. Thereby, the screen printing work for the substrate 9 is executed. The height measurement processing unit 33 controls the sensor moving units 21 and 22 and the three-dimensional measurement sensor 20 to cause the three-dimensional measurement sensor 20 to execute the height measurement result for the clamp member 8a and the substrate 9. . The height measurement processing unit 33 and the three-dimensional measurement sensor 20 are provided so as to be movable in a horizontal plane, and a height measurement unit that performs height measurement using the upper surface of the pair of clamp members 8a and the upper surface of the substrate 9 as measurement targets. Constitute.

  The clamp state control unit 34 sequentially moves the three-dimensional measurement sensor 20 of the height measurement unit to execute the above-described height measurement, and below the substrate based on the height measurement result acquired by the three-dimensional measurement sensor 20. By controlling the operation of the receiving portion 6, a control process for adjusting the relative height between the upper surface of the substrate 9 and the upper surface of the clamp member 8a in a clamped state in which the substrate 9 is sandwiched between the clamp members 8a is performed. That is, the clamp state control unit 34 controls the drive of the Z-axis table 5 of the substrate positioning unit 1 to adjust the height of the substrate 9 held by the substrate receiving unit 6 with respect to the clamp member 8a.

  Detailed functions of the clamp state control unit 34 will be described. In the present embodiment, the clamp state control unit 34 includes a measurement execution unit 34a, a height calculation processing unit 34b, and a height adjustment unit 34c. The measurement execution unit 34a moves the three-dimensional measurement sensor 20 so as to be positioned above the height measurement point, and performs a process of executing height measurement for each height measurement point. FIG. 6 shows a clamp member height measuring operation for the clamp member 8a. As shown in FIG. 6 (a), the pair of clamp members 8a are positioned in the vicinity of both ends, and are clamp member measurement points PC1, PC2 and clamp member measurement points PC3 which are first height measurement points. , PC4 is set. Here, an example in which two height measurement points at both end portions are set for one clamp member 8a has been shown, but it goes without saying that a large number of height measurement points may be set.

  In the height measurement for the clamp member 8a, as shown in FIG. 6B, first, the three-dimensional measurement sensor 20 is moved onto the clamp member 8a on one side, and the clamp member measurement points PC1 and PC2 are targeted. Perform height measurement. When the height measurement processing unit 33 acquires the measurement result, the heights of the clamp member measurement points PC1 and PC2 are detected as the height measurement values HC1 and HC2. Next, the three-dimensional measurement sensor 20 is moved onto another clamp member 8a (arrow b), and the height measurement is similarly performed on the clamp member measurement points PC3 and PC4. When the height measurement processing unit 33 acquires the measurement result, the heights of the clamp member measurement points PC3 and PC4 are detected as height measurement values HC3 and HC4.

  In the height measurement for the substrate 9, as shown in FIG. 7A, substrate measurement points PB (i) that are a plurality of second height measurement points set in a lattice arrangement on the substrate 9. Height measurement is performed on the target. The arrangement of the board measurement points PB (i) is appropriately set according to the size of the board 9 and the degree of warpage deformation. Here, an example is shown in which about 100 height measurement points are arranged in a grid.

  When executing the height measurement, the movement path of the three-dimensional measurement sensor 20 so that the three-dimensional measurement sensor 20 passes through all the substrate measurement points PB (i) in order in advance (see arrow d shown in FIG. 1A). Is set in advance. Then, as shown in FIG. 7 (b), the three-dimensional measurement sensor 20 is moved along the movement path set above the substrate 9 (arrow c), and each substrate measurement point PB (i) is sequentially increased. Execute measurement. When the height measurement processing unit 33 acquires the measurement result, the height of each board measurement point PB (i) is detected as the height measurement value HB (i). That is, the measurement execution unit 34a includes a plurality of first height measurement points (clamp member measurement points PC1, PC2, PC3, PC4) that are set to include at least two points on both ends of each of the pair of clamp members 8a. ) And a plurality of second height measurement points (substrate measurement points PB (i)) set in a regular arrangement in advance on the upper surface of the substrate 9 are executed.

  In the height measurement for the substrate 9, the substrate 9 partially has a notch 9 d, so that the normal position located on the upper surface 9 e of the substrate 9 as shown in FIG. There is a difference in the height measurement result between the board measurement point PB and the board measurement point PB * located in the range of the notch 9d. For example, when the substrate 9 is supported by the substrate support 6, the three-dimensional measurement sensor 20 sets the height of the upper surface of the substrate support 6 that receives the substrate 9 within the range of the notch 9 d. To detect. When the substrate 9 is pin-supported, the three-dimensional measurement sensor 20 detects the height of the holding member of the receiving pin at a lower position in the range of the notch 9d. In any case, a difference in height corresponding to the thickness dimension t of the substrate 9 is detected in the height detection result between the normal substrate measurement point PB and the substrate measurement point PB * located in the range of the notch 9d, or There are even greater height differences. Due to this height difference, the board measurement point PB * located in the range of the notch 9d is regarded as a singular point that is not recognized as the height measurement value of the upper surface of the board 9.

  The height calculation processing unit 34b is a clamp member height HCM (see FIG. 10A) indicating the height of the upper surface of the clamp mechanism 8 as a single representative value based on the plurality of height measurement values described above and the substrate. A height calculation process for calculating a substrate upper surface height HBM (see FIG. 10A) indicating the height of the upper surface 9 with a single representative value is performed. First, for the clamp member 8a, an average value of the four measured clamp member heights HC1, HC2, HC3, and HC4 calculated for the pair of clamp members 8a is calculated to represent a representative value indicating the height of the clamp member 8a. As a clamp member height HCM. Further, for the substrate 9, the average of a plurality of remaining substrate height measurement values HB (i) that reject the height measurement values within the range of the singular point described in FIG. 7C, that is, the notch 9d. A value is calculated and set as a substrate upper surface height HBM as a representative value indicating the height of the substrate 9.

  Here, in order to extract and reject the above-mentioned singular point from the plurality of substrate height measurement values HB (i), data processing is performed according to a predefined statistical processing algorithm. Here, the standard deviations of these measurement values are obtained for all the substrate height measurement values HB (i), and the measurement values clearly deviating from the center of distribution compared with the standard deviation are rejected as singular points. . The determination threshold for rejecting the singular point is set for each board type in consideration of the distribution state by actually obtaining the height measurement value HB (i) for each board.

  That is, the height calculation processing unit 34b calculates the clamp member height HCM by obtaining an average value of the height measurement values obtained with respect to the plurality of first height measurement points, and the plurality of second height measurement points. By processing the height measurement values obtained for the height measurement points according to a predetermined statistical processing algorithm, a plurality of singular points that are not recognized as height measurement values on the upper surface of the substrate 9 are removed. The average value of the height measurement values of the substrate is obtained to calculate the substrate upper surface height HBM.

  Based on the calculated clamp member height HCM and the substrate upper surface height HBM, the height adjusting unit 34c controls the raising / lowering operation of the substrate receiving unit 6 to thereby adjust the upper surface of the substrate 9 and the upper surface of the clamp member 8a. Process to adjust the relative height of. That is, the height adjustment unit 34c obtains a height difference ΔH (see FIG. 10A) between the clamp member height HCM and the substrate upper surface height HBM, and sets the Z-axis table 5 so as to correct the height difference ΔH. By driving, the substrate 9 is moved up and down by a correction amount, and the height is adjusted so that the upper surface of the substrate 9 is aligned with the upper surface of the clamp member 8a. Then, the base height data 31a of the storage unit 31 is updated with the base height in consideration of the height difference Δ obtained for the board type.

  The operation / input unit 35 is an input means such as a keyboard and a touch panel switch, and performs operation commands for operating the screen printing apparatus and various data inputs. The display unit 36 is a display device such as a liquid crystal panel, and displays a guidance screen at the time of operation / input and various notification screens.

  The screen printing apparatus is configured as described above. Next, clamp state control processing in screen printing work by the screen printing apparatus will be described with reference to the drawings in accordance with the flow of FIG. This clamping state control processing is performed even when the substrate such as the substrate 9 which is a multi-sided substrate is likely to be warped and deformed, and the substrate is likely to cause a poor contact state with the mask plate 12. Is a process executed for the purpose of ensuring good adhesion. This clamping state control process has the meaning as a teaching process that is performed to update the receiving height data 31a to appropriate data corresponding to the actual board when the product type is switched to a new board type. It is what you have. Of course, when the variation in thickness and warpage deformation state is large depending on individual substrates, the number of executions may be increased as necessary.

  At the start of the clamp state control process, first, the substrate 9 is loaded by the substrate transfer unit 7 (ST1), and the loaded substrate 9 is received and held by the substrate receiving unit 6 (ST2). This receiving operation is performed by raising the substrate receiving portion 6 based on the receiving height data 31a obtained from the substrate thickness data of the target substrate 9. At this time, the upper surface of the substrate 9 and the clamp member 8a are caused by various factors such as a thickness error of the substrate 9, an erroneous input of thickness data, warpage deformation, and a mechanism error when the substrate receiving portion 6 is raised and lowered by the Z-axis table 5. The height is not necessarily the same as the upper surface, and there may be a height difference ΔH between the upper surface of the substrate 9 and the upper surface of the clamp member 8a as shown in FIG. For this reason, the process for correcting the height difference ΔH is executed as follows by the processing function of the clamp state control unit 34.

  First, the height measurement operation of the first height measurement points (clamp member measurement points PC1, PC2, PC3, PC4) is performed on the clamp member 8a (ST3). That is, as shown in FIG. 9A, the substrate positioning unit 1 drives the Y-axis table 2 to pull out the substrate 9 held by the substrate receiving unit 6 from below the mask plate 12 (arrow e). Then, the height of the clamp member measurement points PC1, PC2, PC3, PC4 is measured by the method shown in FIG. 6, and the clamp member height measurement values HC1, HC2, HC3, HC4 are detected. Next, the height measurement operation of the second height measurement point (substrate measurement point PB (i)) is performed on the upper surface of the substrate 9 (ST4). That is, as shown in FIG. 9B, the three-dimensional measurement sensor 20 is moved above the substrate 9, and the heights of the substrate measurement points PB (i) shown in FIG. The substrate height measurement value HB (i) is detected for the point.

  Next, the clamp member height is calculated based on the measurement result of (ST3) (ST5). That is, the height calculation processing unit 34b calculates the average value of the four height measurement values HC1, HC2, HC3, and HC4, thereby calculating the clamp member height HCM as a representative value indicating the height of the clamp member 8a. Is done. Next, the substrate top surface height is calculated (ST6). That is, the height calculation processing unit 34b performs data processing according to a predetermined statistical processing algorithm, thereby extracting and rejecting the above-mentioned singular points from the plurality of substrate height measurement values HB (i). By calculating the average value of the measured substrate heights HB (i), the substrate upper surface height HBM as a representative value indicating the height of the substrate 9 is calculated.

  Next, the receiving height data is calculated (ST7). That is, based on the calculated clamp member height HCM and substrate upper surface height HBM, a necessary correction value for making the upper surface of the substrate 9 the same height as the upper surface of the clamp member 8a is obtained. Here, as shown in FIG. 10A, a height difference ΔH between the clamp member height HCM and the substrate upper surface height HBM is obtained. Then, new base height data 31a is calculated in consideration of the height difference ΔH, and the existing data stored in the storage unit 31 is updated. Next, the relative height between the upper surface of the substrate 9 and the upper surface of the clamp member 8a is adjusted (ST8). That is, as shown in FIG. 10B, after the clamp mechanism 8 is operated and the clamp state of the substrate 9 is once released by the clamp member 8a, the substrate support 6 is moved up and down by a height difference ΔH which is a correction value. (Arrow g). Then, as shown in FIG. 10C, the substrate 9 is sandwiched and clamped by the clamp member 8a (ST9).

  Thereby, the clamp member height HC and the substrate upper surface height HB are set to substantially the same height with high accuracy. In this state, screen printing is executed (ST10). That is, the substrate 9 clamped by the clamp member 8 a is raised and brought into contact with the lower surface of the mask plate 12, and then the squeegee 16 is slid on the upper surface of the mask plate 12. The cream solder 17 is printed on the substrate 9 via In the screen printing for the same substrate type substrate 9 that is executed thereafter, the substrate underlay operation is executed based on the updated underlay height data 31a. In this screen printing, since the clamp member height HC and the substrate upper surface height HB are the same height, the adhesion between the mask plate 12 and the substrate 9 is improved, and the printing quality is ensured.

  That is, in the above-described screen printing method, the three-dimensional measurement sensor 20 is sequentially moved to perform height measurement, and the operation of the substrate support 6 is controlled based on the height measurement result by the three-dimensional measurement sensor 20. Thus, the clamp state control process is performed in which the relative height between the upper surface of the substrate 9 and the upper surface of the clamp member 8a in the substrate clamp state is adjusted. (ST3) and (ST4) in the above-described flow are a plurality of first height measurement points (clamp member measurement points PC1, PC1 that are set including at least two points on both ends of each of the pair of clamp members 8a. PC2, PC3, PC4) and a measurement execution step for executing a height measurement operation on a plurality of second height measurement points (substrate measurement points PB (i)) set in a regular arrangement in advance on the upper surface of the substrate 9 It has become.

  In addition, (ST5) and (ST6) in the above-described flow are clamp member height measurement values HC1 and HC2 obtained by targeting a plurality of first height measurement points (clamp member measurement points PC1, PC2, PC3, PC4). In addition to calculating the average value of HC3 and HC4, the clamp member height HCM is calculated, and the height measurement values obtained for a plurality of second height measurement points (substrate measurement points PB (i)) ( The substrate height measurement value HB (i)) is subjected to data processing according to a predetermined statistical processing algorithm, whereby a plurality of height measurements excluding singular points that are not recognized as the height measurement value of the upper surface of the substrate 9 are obtained. This is a height calculation processing step for calculating an average value of the values and calculating the substrate upper surface height. Further, (ST7) and (ST8) in the above-described flow indicate that the upper surface of the substrate 9 and the clamp member are controlled by controlling the operation of the substrate receiving portion 6 based on the calculated clamp member height HCM and the substrate upper surface height HBM. This is a height adjustment step for adjusting the relative height of the upper surface of 8a.

  As described above, in the screen printing shown in the present embodiment, the clamp member 8a is set in the clamp state control step of adjusting the relative height between the upper surface of the substrate 9 and the upper surface of the clamp member 8a in the substrate clamp state. The height measurement operation is performed on the plurality of first height measurement points and the plurality of second height measurement points set for the upper surface of the substrate 9 to perform the clamp member height HCM and the substrate upper surface height. HBM is calculated, and the operation of the substrate receiving portion 6 is controlled based on the calculated clamp member height HCM and substrate upper surface height HBM, and the relative height between the upper surface of the substrate 9 and the upper surface of the clamp member 8a is determined. It is intended to be adjusted.

  As a result, when it is difficult to ensure the adhesion between the substrate 9 and the mask plate 12, such as when there is an error between the thickness data of the target substrate 9 and the actual thickness, or when the substrate 9 is warped and deformed. Even so, by actually executing the height measurement, it is possible to eliminate these error factors and set the height of the substrate 9 and the clamp member 8a to be the same. Thereby, the adhesiveness with the mask plate 12 can be improved, and the printing quality defect resulting from the adhesiveness between the board | substrate 9 and the mask plate 12 can be prevented.

  INDUSTRIAL APPLICABILITY The screen printing apparatus and the screen printing method of the present invention have an effect that it is possible to prevent print quality defects caused by the adhesion between the substrate and the mask plate, and cream solder or conductive paste is applied to the substrate. It is useful in the field of printing pastes.

DESCRIPTION OF SYMBOLS 1 Substrate positioning part 2 Y-axis table 3 X-axis table 4 θ-axis table 5 Z-axis table 6 Substrate receiving part 7 Substrate transport part 8a Clamp member 9 Substrate 9a Unit substrate 9d Notch part 10 Screen printing part 12 Mask plate 13 Squeegee Unit 16 Squeegee 17 Cream solder 20 Three-dimensional measurement sensor PC1, PC2, PC3, PC4 Clamp member measurement point HC1, HC2, HC3, HC4 Clamp member height measurement value PB, PB (i) Substrate measurement point HB (i) Substrate height Measured value HC, HCM Clamp member height HB, HBM Upper surface height of substrate

Claims (2)

A screen printing apparatus for printing a paste on a substrate through the pattern hole by bringing the substrate into contact with the lower surface of the mask plate on which the pattern hole is formed and sliding a squeegee on the upper surface of the mask plate to which the paste is supplied. There,
A substrate lower receiving portion that is disposed so as to be movable up and down with respect to the mask plate and receives the substrate and holds it at a printing position on the lower surface side of the mask plate, and transporting the substrate in a first direction. A substrate carrying unit that carries the substrate into the substrate receiving unit and unloads the printed substrate from the substrate receiving unit, and the substrate received by the substrate receiving unit is sandwiched from a second direction orthogonal to the first direction. A pair of clamp members;
A height measuring means that is movably disposed in a horizontal plane and that measures the height of the upper surface of the pair of clamp members and the upper surface of the substrate as measurement objects;
The height measurement unit is sequentially moved to perform height measurement, and the substrate receiving portion is controlled based on a height measurement result by the height measurement unit, whereby the substrate is sandwiched between clamp members. A clamp state control unit that adjusts a relative height between the upper surface of the substrate and the upper surface of the clamp member in a clamped state;
Further, the clamp state control unit is preset in a regular arrangement with respect to the plurality of first height measurement points set to include at least two points on both ends of each of the pair of clamp members and the upper surface of the substrate. A measurement execution unit that executes height measurement work on a plurality of second height measurement points;
The clamp member height is calculated by obtaining an average value of the height measurement values obtained for the plurality of first height measurement points, and is obtained for the plurality of second height measurement points. By processing the obtained height measurement values according to a predetermined statistical processing algorithm, an average value of a plurality of height measurement values excluding singular points that are not recognized as height measurement values on the upper surface of the substrate is obtained. A height calculation processing unit for calculating the upper surface height of the substrate,
A height adjusting unit that adjusts a relative height between the upper surface of the substrate and the upper surface of the clamp member by controlling the substrate lower receiving portion based on the calculated clamp member height and the substrate upper surface height; A screen printing apparatus comprising: A substrate lower receiving portion that is disposed so as to be movable up and down with respect to the mask plate and holds the substrate at a printing position on the lower surface side of the mask plate; and by transporting the substrate in the first direction A pair of a substrate carrying unit that carries the substrate into the receiving unit and unloads the printed substrate from the substrate receiving unit and a substrate that is received by the substrate receiving unit from a second direction orthogonal to the first direction. A clamping member of
A pattern hole is formed by a screen printing apparatus that is movably arranged in a horizontal plane and includes a height measuring unit that measures the height of the upper surface of the pair of clamp members and the upper surface of the substrate as measurement targets. A screen printing method for printing a paste on the substrate through the pattern hole by bringing the substrate into contact with the lower surface of the mask plate and sliding a squeegee on the upper surface of the mask plate supplied with the paste,
The height measurement unit is sequentially moved to perform height measurement, and the substrate lower portion is controlled based on the height measurement result by the height measurement unit, thereby the upper surface of the substrate in the substrate clamped state. And a clamp state control step of adjusting the relative height between the upper surface of the clamp member and the clamp member,
Further, in the clamp state control step, a plurality of first height measurement points set including at least two points on both ends of each of the pair of clamp members and an upper surface of the substrate are set in a regular arrangement in advance. A measurement execution step for performing height measurement work on a plurality of second height measurement points,
The clamp member height is calculated by obtaining an average value of the height measurement values obtained for the plurality of first height measurement points, and is obtained for the plurality of second height measurement points. By processing the obtained height measurement values according to a predetermined statistical processing algorithm, an average value of a plurality of height measurement values excluding singular points that are not recognized as height measurement values on the upper surface of the substrate is obtained. A height calculation processing step for calculating and calculating a substrate upper surface height;
A height adjusting step of adjusting a relative height between the upper surface of the substrate and the upper surface of the clamp member by controlling the substrate lower receiving portion based on the calculated clamp member height and the substrate upper surface height; A screen printing method comprising:

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