JP2010064425A - Screen-printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screen-printing method capable of eliminating printing defects caused by short filling with paste in pattern openings. <P>SOLUTION: In the screen-printing method comprising: supplying paste 50 by contacting mask plate 4 formed with the pattern openings 4b to a substrate PB; filling the paste 50 into the pattern openings 4b by moving relatively to the mask plate 4 a squeegee 5a contacting the mask plate 4; and thereafter separating the mask plate 4 from the substrate PB to transfer the paste 50 in the pattern openings 4b onto the substrate PB, a relative moving rate of the squeegee 5a to the mask plate 4 is varied depending on a detected form of the paste 50 by detecting the form of the paste 50 transferred onto the substrate PB in the height direction from the substrate PB. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a screen printing method for transferring a paste to an object to be printed using a mask plate in which pattern holes are formed.

  In screen printing in which paste is transferred to an object to be printed such as a substrate, the paste is supplied by bringing the mask plate with a pattern hole into contact with the object to be printed, and the squeegee that is in contact with the mask plate is relative to the mask plate. After moving and filling the pattern holes with paste, the object to be printed and the mask plate are separated (so-called plate separation). As a result, a paste having a shape corresponding to the pattern hole is transferred (printed) to the print object.

In such screen printing, an observation is made from above the printed object after printing, and when there is a printing failure of the paste, the printing condition is changed to improve the printing failure state. For example, in Patent Document 1, a printed object with good appearance and uniform appearance without bleed or unevenness is observed by observing the printed object after printing and changing the squeegee running speed according to the surface condition of the printed object. The technique that can be obtained is shown.
JP-A-2-308589

  However, among the printing defects that may occur in screen printing, the paste is not sufficiently filled in the pattern holes, so the paste after transfer to the printing object is high (height from the printing object). There is a shortage type. Such poor printing due to insufficient filling of the paste in the pattern hole is difficult to find just by looking at the surface of the print object, such as the above-mentioned printing blur or unevenness, Therefore, there was a problem that the improvement was difficult.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a screen printing method that can improve printing defects caused by insufficient filling of paste into pattern holes.

  The screen printing method according to claim 1, wherein a paste is supplied by bringing a mask plate in which pattern holes are formed into contact with an object to be printed, and a squeegee that is in contact with the mask plate is moved relative to the mask plate. The process of filling the pattern hole with paste, the process of transferring the paste in the pattern hole to the print object by separating the print object and the mask plate, and the print object of the paste transferred to the print object Detecting the shape of the squeegee in the height direction, and changing the relative movement speed of the squeegee with respect to the mask plate in accordance with the detected shape of the paste.

  The screen printing method according to claim 2 is the screen printing method according to claim 1, wherein the detected paste is transferred to the printing object based on the shape in the height direction from the printing object. When it is detected that an inclined surface having a gradient rising in the moving direction of the squeegee is formed on the upstream side of the moving direction of the paste squeegee, the relative moving speed of the squeegee with respect to the mask plate is increased.

In the screen printing method of the present invention, the shape of the printed paste in the height direction from the printing object is detected, and the relative movement speed of the squeegee with respect to the mask plate is changed according to the detected shape of the paste. ing. If the printed paste has a printing defect with insufficient height due to insufficient filling of the paste in the pattern hole, this is due to the height direction of the paste after printing on the printing object (the height from the printing object). (For example, an inclined surface with a gradient rising toward the movement direction of the squeegee is formed on the upstream side of the movement direction of the paste squeegee), and the paste is insufficiently filled. Can be improved by increasing the relative movement speed of the squeegee with respect to the mask plate, the screen printing method of the present invention improves printing defects caused by insufficient filling of the paste in the pattern holes. be able to.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a screen printer according to an embodiment of the present invention, FIG. 2 is a side view of the screen printer according to an embodiment of the present invention, and FIG. 3 is a screen printer according to an embodiment of the present invention. FIG. 4 is a block diagram showing a control system of the screen printer in one embodiment of the present invention, and FIGS. 5A and 5B are operations of the screen printer in one embodiment of the present invention. FIG. 6 (a), (b), (c), FIG. 7 (a), (b), (c) and FIG. 8 (a), (b), (c) are one embodiment of the present invention. FIG. 9 is a flowchart showing an example of a screen printing procedure executed by the screen printer according to one embodiment of the present invention.

  1 and 2, the screen printing machine 1 has a substrate alignment unit 3 on a base 2, and a mask plate 4, a squeegee head 5, and a camera unit 6 are provided above the substrate alignment unit 3. It has been.

  1 and 2, the substrate alignment unit 3 includes a horizontal alignment mechanism 10 and a vertical alignment mechanism 11.

  The horizontal alignment mechanism 10 is provided on the upper surface side of the base 2 so as to be movable in one direction in the horizontal plane with respect to the base 2 (the left-right direction on the paper surface of FIG. 1, the Y-axis direction). The Y table 14 is provided on the upper surface side of the Y table 14 so as to be movable in a direction in a horizontal plane perpendicular to the Y axis with respect to the Y table 14 (a direction perpendicular to the paper surface of FIG. 1 and referred to as the X axis direction). The X table 15 and the θ table 16 provided on the upper surface side of the X table 15 so as to be rotatable in a horizontal plane with respect to the X table 15 are provided.

  When the Y table drive motor 17 provided on the Y table 14 is rotated, the Y table 14 moves in the Y-axis direction with respect to the base 2 and the X table drive motor 18 provided on the X table 15 is rotated. When the X table 15 moves in the X-axis direction with respect to the Y table 14 and the θ table drive motor 19 (see FIG. 4) provided on the θ table 16 is rotated, the θ table 16 moves relative to the X table 15. Rotate. The operation control of the Y table drive motor 17, the X table drive motor 18 and the θ table drive motor 19 is performed by a control device 20 provided in the screen printing machine 1 (FIG. 4).

  The vertical alignment mechanism 11 includes a base plate 22 fixed to the θ table 16, a first elevating plate 23 provided above the base plate 22 so as to be movable up and down with respect to the base plate 22, and a first above the first elevating plate 23. It has the 2nd raising / lowering plate 24 provided so that raising / lowering with respect to the raising / lowering plate 23 was possible, and the board | substrate support block 25 fixed above the 2nd raising / lowering plate 24. As shown in FIG.

When the first elevating motor 26 provided on the base plate 22 is rotated, a plurality of first elevating screws 28 that are vertically supported by the first elevating plate 23 are rotationally driven via the first belt 27. The 1st raising / lowering plate 23 screwed in 1 raising / lowering screw 28 raises / lowers. Further, when the second lifting / lowering motor 29 provided on the first lifting / lowering plate 23 is rotated, the plurality of second lifting / lowering screws 31 that are vertically supported by the second lifting / lowering plate 24 are rotated via the second belt 30. When driven, the second elevating plate 24 screwed into the second elevating screws 31 (that is, the substrate support block 25) moves up and down. Operation control of the first elevating motor 26 and the second elevating motor 29 is performed by the control device 20.

  The vertical alignment mechanism 11 is also supported by a plurality of vertical frames 34 erected on the first elevating plate 23 and extends in the X-axis direction, and is transported above the transport conveyor 35. A pair of clamp members 36 (see also FIG. 3) provided in parallel with the conveyor 35 are provided. The pair of transport conveyors 35 can be driven by a rotation operation of a conveyor drive motor 37 (see FIG. 4) provided in the vicinity of the transport conveyor 35. Further, the pair of clamp members 36 are arranged to face each other in the Y axis direction, and are driven to open and close in the Y axis direction by being driven by a clamp cylinder 38 fixed to the vertical frame 34. Operation control of the conveyor drive motor 37 and the clamp cylinder 38 is performed by the control device 20.

  1, 2, and 3, the mask plate 4 has four sides supported by a rectangular mask frame 4 a, and an electrode D (on the substrate PB that is a printing target) is surrounded by an inner region surrounded by the mask frame 4 a. A large number of pattern holes 4b corresponding to the shape and position of FIG. 3) are provided.

  In FIG. 2, the base 2 is provided with a pair of vertical frames 39 erected so as to face each other in the X-axis direction with the substrate alignment portion 3 interposed therebetween. A first guide rail 40 and a second guide rail 41 extending in the axial direction are provided. Both ends of the first slider 44 extending in the X-axis direction are supported by the pair of first guide rails 40, and both ends of the second slider 45 also extending in the X-axis direction are supported by the pair of second guide rails 41. The part is supported.

  In FIGS. 1 and 2, the squeegee head 5 is fixed to the first slider 44. The first slider 44 is moved in the Y-axis direction along the first guide rail 40 by the rotation operation of the first slider drive motor 46 (see FIG. 4), whereby the squeegee head 5 is moved in the Y-axis direction. The operation control of the first slider drive motor 46 is performed by the control device 20.

  The squeegee head 5 includes two squeegees 5a provided to face each other in the Y-axis direction, and two squeegee lifting cylinders 5b for raising and lowering each squeegee 5a. Each squeegee 5a has a shape extending in the X-axis direction, and the attack angle can be changed by operating the attack angle changing cylinder 5c (see FIG. 4). Here, the attack angle is an angle α formed by the squeegee 5a with respect to the substrate PB or the mask plate 4 in a horizontal posture (FIG. 1). Operation control of each squeegee lifting cylinder 5b and attack angle changing cylinder 5c is performed by the control device 20.

  The camera unit 6 is provided on the second slider 45 so as to be movable in the X-axis direction. The second slider 45 is moved in the Y-axis direction along the second guide rail 41 by the rotation of the second slider drive motor 48 (see FIG. 4), and the camera unit 6 is rotated by the camera moving motor 49 (see FIG. 4). The second slider 45 is moved in the X-axis direction by the operation. Therefore, the camera unit 6 can be moved freely within the horizontal plane. The operation control of the second slider drive motor 48 and the camera movement motor 49 is performed by the control device 20.

  As shown in FIGS. 1, 2 and 3, the camera unit 6 has a first camera 6a with the imaging surface facing downward, a second camera 6b with the imaging surface facing upward, and an imaging surface facing downward. A third camera 6c is provided. The first camera 6 a performs image recognition of a substrate position detection mark (not shown) provided on the substrate PB on the substrate alignment unit 3, and the second camera 6 b is a mask provided on the mask plate 4. Image recognition of a position detection mark (not shown) is performed. Further, the third camera 6c recognizes the three-dimensional shape including the shape in the height direction from the substrate PB of the paste 50 printed on the substrate PB by the squeegee 5a. For example, the third camera 6c has a configuration for detecting a three-dimensional shape to be recognized using a laser or infrared rays. Operation (imaging) control of the first camera 6a, the second camera 6b, and the third camera 6c is performed by the control device 20, and data captured by these cameras 6a, 6b, and 6c is input to the control device 20 (FIG. 4). ).

  Next, a procedure for printing paste on the substrate PB executed by the screen printer 1 will be described. When the substrate PB is sent from an upstream device (not shown) of the screen printing machine 1, the control device 20 of the screen printing machine 1 controls the conveyor drive motor 37 to transfer the substrate PB to the transport conveyor 35. Receive it and transport it to a predetermined position. Then, the second elevating motor 29 is operated to raise the second elevating plate 24 relative to the first elevating plate 23, and the substrate support block 25 is pressed against the lower surface of the substrate PB to support the substrate PB on the substrate support block 25. Let When the controller 20 supports the substrate PB on the substrate support block 25, the clamp cylinder 38 is operated to close the clamp member 36, and the substrate PB is clamped from both sides.

  After the substrate PB is clamped by the clamp member 36, the control device 20 performs the movement and imaging control of the first camera 6a to cause the first camera 6a to perform image recognition of the substrate position detection mark of the substrate PB, and In addition to grasping the position, the second camera 6b is moved and imaged to perform image recognition of the mask position detection mark of the mask plate 4 to grasp the position of the mask plate 4.

  After grasping the position of the substrate PB and the position of the mask plate 4, the control device 20 controls the operation of the horizontal alignment mechanism 10 to position the substrate PB at a predetermined position directly below the mask plate 4 (in the horizontal direction). Alignment). The movement of the substrate PB in the horizontal direction is the movement of the Y table 14 in the Y axis direction with respect to the base 2, the movement of the X table 15 in the X axis direction with respect to the Y table 14, and the θ table 16 in the horizontal plane with respect to the X table 15. Combined with rotation in

  When the horizontal alignment of the substrate PB is finished, the control device 20 controls the operation of the vertical alignment mechanism 11 to bring the upper surface of the substrate PB into contact with the lower surface of the mask plate 4 (vertical alignment). . The movement of the substrate PB in the vertical direction is performed by raising the first elevating plate 23 with respect to the base plate 22 (FIG. 5B). Thus, the alignment of the substrate PB with respect to the mask plate 4 by the control device 20 (horizontal alignment and vertical alignment) is completed.

  When the alignment of the substrate PB with respect to the mask plate 4 is completed, the control device 20 executes screen printing on the substrate PB. To this end, the control device 20 first controls the operation of a paste supply unit (not shown) to supply a paste 50 such as a solder paste or a conductive paste to the upper surface of the mask plate 4, and then operates the squeegee lifting cylinder 5b. Control is performed to lower one squeegee 5 a and bring the lower edge of the squeegee 5 a into contact with the upper surface of the mask plate 4.

When the lower edge of one squeegee 5a is brought into contact with the upper surface of the mask plate 4, the control device 20 controls the operation of the first slider drive motor 46 to move the squeegee head 5 in the Y-axis direction (FIG. 5 ( b) and an arrow A) shown in FIG. 6A, the paste 50 is scraped by the squeegee 5a and filled in the pattern holes 4b of the mask plate 4 one after another (see FIG. 6B). .

  FIG. 5B shows a state in which the paste 50 is scraped in the direction of arrow A by moving the left squeegee 5a in the direction of arrow A in the figure. When the paste 50 is scraped in the direction opposite to the arrow A, the right squeegee 5a in the drawing is brought into contact with the upper surface of the mask plate 4 and moved in the direction opposite to the arrow A.

  When the control device 20 fills the pattern hole 4b of the mask plate 4 with the paste 50, the control device 20 operates the second lifting / lowering motor 29 to lower the second lifting / lowering plate 24 to separate the mask plate 4 from the substrate PB (FIG. 6 (c), arrow B). Thus, so-called plate separation is performed, and the paste 50 filled in the pattern holes 4b of the mask plate 4 is transferred (printed) onto the substrate PB (FIG. 6C).

  Here, as shown in FIGS. 6A and 6B, when the plate separation is performed from the state where the paste 50 is sufficiently filled in the pattern hole 4b of the mask plate 4, FIG. As shown in FIG. 4, an ideal-shaped paste 50 that is almost the same as the spatial three-dimensional shape in the pattern hole 4b is transferred to the substrate PB. For example, if the pattern hole 4b has a shape in which a rectangular parallelepiped shape is cut out, an ideal-shaped paste 50 having a substantially rectangular parallelepiped shape is transferred to the substrate PB.

  However, as shown in FIGS. 7A and 7B, the paste 50 is not sufficiently filled in the pattern hole 4b of the mask plate 4, and the moving direction of the squeegee 5a in the pattern hole 4b (in FIG. 7). When the plate separation is performed from the state where the space SP is in the upstream (left side of FIG. 7) portion in the direction from the left side to the right side of the paper surface, a paste having a shape different from the ideal shape is applied to the substrate PB. 50 will be transferred. As shown in FIG. 7C, the shape of the paste 50 at this time is a gradient that rises in the moving direction of the squeegee 5a toward the upstream side in the moving direction of the squeegee 5a (in FIG. 7, from the lower left side of the page). An inclined surface 50a having a gradient in a direction toward the upper right) is formed.

  For this reason, when an inclined surface 50a having a gradient rising in the moving direction of the squeegee 5a is formed on the upstream side in the moving direction of the squeegee 5a of the paste 50 transferred to the substrate PB, the pattern hole 4b It can be seen that the filling of the paste 50 inside was insufficient. Note that the paste 50 transferred to the substrate PB has such a shape that the height of the paste 50 (height from the printing object) is insufficient, that is, the printing failure is insufficient. It means that it has occurred. If a printing defect with insufficient height occurs, there is a possibility that a defective bonding of components may occur in a subsequent step of mounting the component on the substrate PB or the like.

  Here, the insufficient filling of the paste 50 into the pattern hole 4b as described above occurs because the moving speed of the squeegee 5a with respect to the mask plate 4 (hereinafter referred to as squeegee moving speed) is small. This is probably because the rolling of the paste 50 is insufficient. Therefore, an inclined surface 50a having a gradient rising in the moving direction of the squeegee 5a is formed on the upstream side in the moving direction of the squeegee 5a of the paste 50 after being transferred to the substrate PB, and the pattern hole When it is considered that the filling of the paste 50 into the 4b is insufficient, the rolling of the paste 50 is promoted by increasing the squeegee moving speed with respect to the mask plate 4 to thereby paste the paste 50 into the pattern hole 4b. Insufficient filling can be improved.

  Therefore, in the screen printing procedure (screen printing method) executed by the screen printer 1 according to the present embodiment, for example, in the stage of setting the printing conditions such as the squeegee moving speed and the plate separating speed, the trial screen printing is executed. Then, after the screen printing, the third camera 6c is moved and imaged, and the three-dimensional shape including the shape in the height direction of the paste 50 transferred from the substrate PB from the substrate PB is detected. The squeegee moving speed is changed according to the detected shape of the paste 50. Specifically, when it is detected that an inclined surface 50a having a gradient rising in the moving direction of the squeegee 5a is formed on the upstream side in the moving direction of the squeegee 5a of the paste 50 transferred to the substrate PB. Increases the speed of squeegee movement.

  Further, as shown in FIGS. 8A, 8B, and 8C, even when the plate separation is performed from the state in which the paste 50 is sufficiently filled in the pattern holes 4b of the mask plate 4, as shown in FIGS. When the plate separation speed is not appropriate, the paste 50 remaining in the pattern hole 4b increases, and the paste 50 transferred to the substrate PB includes not only the upstream surface in the moving direction of the squeegee 5a but also the squeegee. An inclined surface 50b (this inclined surface 50b is an inclined surface having a gradient descending toward the moving direction of the squeegee 5a) is also generated downstream of the moving direction of the squeegee 5a, and the paste 50 transferred to the substrate PB is moved in the moving direction of the squeegee 5a. The side shape of the paste 50 viewed from the horizontal direction (here, the Y-axis direction) perpendicular to the triangle is a triangle (a shape close to a triangle) (FIG. 8C). And as the plate separation speed is slower, the triangular top portion T tends to be closer to the downstream side in the moving direction of the squeegee 5a (the right side in FIG. 8).

  As described above, when the shape of the side surface of the paste 50 transferred to the substrate PB is a triangle due to an inappropriate plate separation speed, as in the case of insufficient filling of the paste 50 into the pattern hole 4b. Since the printing defect of the insufficient height of the paste 50 arises, it needs to be improved.

  Therefore, in the screen printing procedure executed by the screen printer 1 according to the present embodiment, for example, in the stage of setting the above printing conditions, after performing trial screen printing, the movement and imaging of the third camera 6c. Control is performed to detect the shape of the paste 50 transferred to the substrate PB in the height direction from the substrate PB, and relative to the separation of the substrate PB and the mask plate 4 according to the detected shape of the paste 50 The speed is changed. Specifically, based on the detected shape of the paste 50 in the height direction from the substrate PB, the side surface shape of the paste 50 as viewed from the horizontal direction perpendicular to the moving direction of the squeegee 5a. Is detected to be a triangle, the relative speed when separating the substrate PB and the mask plate 4 is increased. In addition, the greater the degree that the triangular apex T approaches the moving direction of the squeegee 5a, the greater the relative speed at which the substrate PB and the mask plate 4 are separated.

  FIG. 9 is a flowchart showing an example of a screen printing procedure executed by the screen printing machine 1 according to the present embodiment, and shows an example at a stage of setting the squeegee moving speed and the plate separation speed.

In setting the squeegee movement speed and the plate separation speed, the control device 20 first temporarily sets the squeegee movement speed and the plate separation speed and executes screen printing on a trial basis (step ST1). After executing screen printing on the substrate PB, the control device 20 detects the three-dimensional shape of the paste 50 transferred to the substrate PB by the screen printing (step ST2), and moves the squeegee 5a of the paste 50. It is determined whether or not an inclined surface 50a having a gradient rising in the moving direction of the squeegee 5a is formed on the upstream side in the direction (step ST3). As a result, the control device 20 does not have an inclined surface 50a having a gradient rising in the moving direction of the squeegee 5a on the upstream side of the squeegee 5a of the paste 50 transferred to the substrate PB. When it is detected that the shape is almost ideal (for example, FIG. 6C)
In this case, the current conditions (the squeegee movement speed and the plate separation speed temporarily set in step ST1) are stored as they are in the storage unit 20a (FIG. 4) as final decision printing conditions (step ST4).

  On the other hand, when the control device 20 detects in step ST3 that an inclined surface 50a having a gradient rising in the moving direction of the squeegee 5a is formed on the upstream side of the moving direction of the squeegee 5a of the paste 50. After increasing the squeegee moving speed and executing screen printing again (step ST5), the third camera 6c detects the three-dimensional shape of the paste 50 printed on the substrate PB (step ST6). Then, it is determined from the detected three-dimensional shape of the paste 50 whether the shape of the paste 50 has changed in the improvement direction (direction approaching the ideal shape) (step ST7). As a result, the shape of the paste 50 is improved. The reason why the inclined surface 50a having the gradient rising in the moving direction of the squeegee 5a is formed on the upstream side in the moving direction of the squeegee 5a of the paste 50 is Since it becomes clear that the paste 50 is insufficiently filled, Steps ST5 to ST7 are performed again. In step ST7, when the shape of the paste 50 no longer changes in the improving direction, the optimum squeegee moving speed data obtained so far (the squeegee moving speed when the shape of the paste 50 is closest to the ideal shape). ) Is stored and the process proceeds to the next step ST9.

  In addition, when it is detected in the first step ST7 that the shape of the paste 50 has not changed in the improvement direction, the paste 50 rises toward the moving direction of the squeegee 5a upstream of the moving direction of the squeegee 5a. It is clear that one of the reasons why the inclined surface 50a having the gradient to be formed does not include insufficient filling of the paste 50 into the pattern hole 4b (no insufficient filling of the paste 50 occurs). Without repeating step ST5 to step ST7, the current squeegee moving speed (temporarily set in step ST1) is stored as it is in step ST8, and the process proceeds to step ST9.

  In step ST9, based on the three-dimensional shape of the paste 50 detected in the latest step ST6, the paste 50 as viewed from the horizontal direction (Y-axis direction) perpendicular to the moving direction of the squeegee 5a is displayed. It is determined whether the side shape of the triangle is a triangle. As a result, if the side surface shape of the paste 50 is not a triangle (close to the ideal rectangular parallelepiped shape), it can be said that the plate separation speed is appropriate, so that the current (temporarily set in step ST1) ) The plate separation speed is stored as it is (step ST10). On the other hand, when the side surface shape of the paste 50 is a triangle (for example, the case shown in FIG. 8C), screen printing is executed by increasing the plate separation speed (step ST11), and the third camera 6c is set again. The three-dimensional shape of the paste 50 is detected (step ST12), and it is determined whether or not the shape of the paste 50 has changed in the improvement direction (direction approaching the ideal shape) (step ST13). As a result, when the shape of the paste 50 is changing in the improving direction, it is considered that the reason why the side surface shape of the paste 50 is triangular is that the plate separation speed was not appropriate (slow). Then, Step ST11 to Step ST13 are executed again. In step ST13, when the shape of the paste 50 no longer changes in the improvement direction, the optimum one from the data of the plate separation speed obtained so far (the plate separation speed when the shape of the paste 50 is closest to the ideal shape). ) Is stored (step ST14). It should be noted that in step ST11, the plate separation speed is increased as the apex T of the triangular shape of the side surface shape of the paste 50 transferred to the substrate PB is closer to the moving direction of the squeegee 5a (the right side in FIG. 8). Thus, the plate separation speed can be brought close to the optimum value efficiently.

As described above, in the screen printing method according to the present embodiment (screen printing procedure executed by the screen printer 1), the mask plate 4 in which the pattern holes 4b are formed is brought into contact with the substrate PB that is a printing object. A paste supplying step for supplying the paste 50; a paste filling step for filling the pattern hole 4b with the paste 50 by moving the squeegee 5a in contact with the mask plate 4 relative to the mask plate 4; and the substrate PB and the mask plate. A paste transfer step of transferring the paste 50 in the pattern hole 4b to the substrate PB by separating 4 and a shape detection step of detecting the shape of the paste 50 transferred to the substrate PB in the height direction from the substrate PB; Depending on the shape of the paste 50 detected in the shape detection step, the squeegee moving speed (squeegee) It has to include a squeegee movement speed changing step of changing the relative moving velocity) with respect to the mask plate 4 of a.

  Thus, in the screen printing method according to the present embodiment, the shape of the paste 50 transferred (printed) to the substrate PB in the height direction from the substrate PB is detected, and according to the detected shape of the paste 50, Although the squeegee moving speed is changed, when the filling of the paste 50 is insufficient, this can be detected from the shape of the paste 50 in the height direction from the substrate PB (the paste 50). An inclined surface 50a having a gradient rising in the moving direction of the squeegee 5a is formed on the upstream side of the moving direction of the squeegee 5a), and insufficient filling of the paste 50 is improved by increasing the moving speed of the squeegee. Therefore, according to the screen printing method in the present embodiment, it is possible to improve the printing defect due to insufficient filling of the paste 50. Kill.

  In the above-described example, the squeegee 5a is positioned upstream of the movement direction of the squeegee 5a of the paste 50 transferred to the substrate PB based on the shape of the paste 50 from the substrate PB detected in the shape detection step. When it is detected that the inclined surface 50a having the gradient rising in the moving direction is formed, the squeegee moving speed (relative moving speed of the squeegee 5a with respect to the mask plate 4) is increased. When an inclined surface 50a having a gradient rising in the moving direction of the squeegee 5a is formed on the upstream side of the moving direction of the squeegee 5a of the paste 50 transferred to the substrate PB, the paste 50 into the pattern hole 4b is formed. Insufficient filling of the paste 50 is presumed, and it is possible to discover and improve the underfilling of the paste 50 by a simple method. It has become shall.

  Further, in the screen printing method according to the present embodiment, after the shape detection step, along with the squeegee movement speed changing step (after the squeegee movement speed changing step in the above example), depending on the shape of the paste 50 detected in the shape detection step. Thus, a separation relative speed changing step for changing the relative speed when the substrate PB and the mask plate 4 are separated is included. Then, the change of the relative speed when separating the substrate PB and the mask plate 4 is based on the detected shape of the paste 50 in the height direction from the substrate PB and the paste 50 transferred to the substrate PB of the squeegee 5a. The relative speed when separating the substrate PB and the mask plate 4 is increased when it is detected that the shape (side surface shape) of the paste 50 viewed from the horizontal direction orthogonal to the moving direction is a triangle. The relative speed at which the object to be printed and the mask plate are separated increases as the degree to which the apex of the triangle approaches the moving direction of the squeegee. Thereby, even when the printing defect with insufficient height of the paste 50 has occurred due to an inappropriate (slow) plate separation speed, this can be improved.

  Although the embodiment of the present invention has been described so far, the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the printing object is a substrate, but this is an example, and a substrate other than the substrate may be used.

Further, the present invention is characterized in that it has a step of changing the relative movement speed of the squeegee with respect to the mask plate in accordance with the shape in the height direction of the paste transferred from the print object to the print object. Relative moving speed of the squeegee with respect to the mask plate when it is detected that an inclined surface rising in the moving direction of the squeegee is formed on the upstream side of the moving direction of the paste squeegee transferred to the object. Increasing the squeegee is only one method, and the content of the change in the relative movement speed of the squeegee with respect to the mask plate performed according to the shape in the height direction of the paste is not limited to this.

  Provided is a screen printing method capable of improving printing defects caused by insufficient filling of paste into pattern holes.

The front view of the screen printer in one embodiment of the present invention The side view of the screen printer in one embodiment of the present invention The partial top view of the screen printer in one embodiment of this invention The block diagram which shows the control system of the screen printer in one embodiment of this invention (A) (b) Operation | movement explanatory drawing of the screen printer in one embodiment of this invention (A) (b) (c) The figure which shows the printing state when screen printing is performed with the screen printer in one embodiment of this invention. (A) (b) (c) The figure which shows the printing state when screen printing is performed with the screen printer in one embodiment of this invention. (A) (b) (c) The figure which shows the printing state when screen printing is performed with the screen printer in one embodiment of this invention. The flowchart which shows an example of the screen printing procedure which the screen printer in one embodiment of this invention performs

Explanation of symbols

1 Screen Printer 4 Mask Plate 4b Pattern Hole 5a Squeegee 50 Paste 50a Inclined Surface PB Substrate (Printing Object)

Claims (2)

Supplying the paste by bringing the mask plate on which the pattern holes are formed into contact with the object to be printed;
Filling the paste into the pattern holes by moving the squeegee in contact with the mask plate relative to the mask plate;
Transferring the paste in the pattern hole to the printing object by separating the printing object and the mask plate; and
Detecting a shape in a height direction from the printing object of the paste transferred to the printing object;
Changing the relative movement speed of the squeegee with respect to the mask plate according to the shape of the detected paste;
A screen printing method comprising:   Based on the detected shape of the paste from the print object in the height direction, the slope of the gradient rising toward the movement direction of the squeegee upstream of the movement direction of the paste squeegee transferred to the print object The screen printing method according to claim 1, wherein when it is detected that the squeegee is formed, a relative moving speed of the squeegee with respect to the mask plate is increased.

Images