JP2012045758A - Off-contact printing method, printing device using the off-contact printing method and ball mounting device using the off-contact printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct a deviation in printing position of a printing agent caused by a gap between a mask and a base plate and manufacturing errors of dimensions of the mask and the base plate, in an off-contact printing method.SOLUTION: In this printing method for performing off-contact printing of the printing agent on the base plate by using a printing device including the mask fixed to a frame body of the printing device, a stage arranged below the mask so as to be movable, the base plates fixed to the stage and a squeegee printing the printing agent supplied to the top face of the mask from an opening of the mask to an electrode of the base plate, positional shift amount of the printing agent printed on the first base plate is actually measured, and to reduce the positional shift amount, the stage on which the base plate is placed is moved based on the shift amount during printing of the second base plate.

Description

  The present invention relates to an off-contact printing method of a flux (printing agent) used in a ball mounting device, a printing device using the off-contact printing method, and a ball mounting device using the off-contact printing method, and more specifically, correction of a printing position deviation. This relates to the printing method. Furthermore, the present invention relates to a printing apparatus and a ball mounting apparatus using this off-contact printing method.

A printing method in which flux is printed off-contact from an opening formed in a mask on an electrode formed on a substrate has been put to practical use. A mask design method is also known in which a printing position deviation caused by a cap between a mask and a substrate is geometrically calculated to correct a mask design value in advance.

However, a method for correcting the design value of the mask with high accuracy using a geometric calculation value or the like has many parameters (for example, Young's modulus of the material constituting the mask, Poisson's ratio, pasting strength, squeegee via flux). And the friction coefficient of the mask) are necessary, and it is difficult to correct the design value of the mask with high accuracy.

Furthermore, the above method has a fatal defect that cannot correct the manufacturing error of the mask and the substrate. The manufacturing error of a large-sized fine pitch mask and substrate is small between adjacent openings and electrodes, but if they are accumulated, they become larger with respect to the pitch interval. For example, the maximum value of the manufacturing error between the substrate electrodes having the electrode formation region length of 300 mm is approximately ± 15 μm, and the manufacturing error between the mask openings having the opening formation region length of 300 mm is approximately ± 20 μm. Therefore, when the flux is printed on the electrode of the substrate using the mask with such accuracy, the positional deviation amount between the printed flux and the electrode is about plus or minus 25 μm at the maximum. For this reason, when the electrode diameter is 50 μm, the area of the electrode covered by the flux may be half or less. In the fine pitch flux printing, the thickness of the flux covering the electrode is reduced, resulting in poor bonding due to insufficient flux due to misalignment of the flux printing.

JP 2001-179935 A

  The problem to be solved is that it is impossible to correct both the flux printing position deviation due to the gap between the mask and the substrate and the flux printing position deviation due to the manufacturing error between the mask and the substrate. .

  The present invention is caused by flux printing misalignment due to cap printing, flux misprinting based on mask and substrate manufacturing errors, and other factors (for example, mask elongation due to squeegee pressing friction during printing). The main feature is to collectively correct the misalignment of the flux printing caused by the above. Further, the present invention is characterized in that manufacturing errors in the dimensions of the mask and the substrate are corrected by utilizing the characteristics of off-contact printing.

The off-contact printing method of the present invention includes a step of mounting a substrate on a stage, a step of aligning the substrate with a mask, a step of setting a distance between the substrate and the mask to a predetermined distance, and supplying a printing agent onto the mask. A step of lowering the squeegee to bring a part of the mask into contact with the substrate, a printing step of moving the squeegee along the substrate and printing the printing agent on the substrate from the opening disposed in the mask, In the off-contact printing method comprising a step of raising the squeegee and separating the mask from the substrate after the printing step, and a step of sending the substrate to the next step, a printing agent printed using the first substrate, Based on the displacement amount measurement step for measuring the displacement amount of the electrode and the displacement amount, the second substrate is moved so that the printing agent that is printed first does not deviate from the electrode of the second substrate that is printed first. And the process Based on the amount, while moving the second substrate in the moving direction of the squeegee, characterized in that it comprises a step of printing a print material on the second substrate.
A feature of the present invention is that printing is performed while moving another substrate based on data obtained by measuring a printing deviation of a printing agent printed on the electrode, and the second substrate is not only the second, Third, fourth and further m (m is an integer of 5 or more) substrates are included.

According to the present invention, in the deviation amount measurement step, the deviation amount measurement position is considerably different from the first measurement position to the nth (n is an integer of 2 or more) measurement position, and the deviation amount between two predetermined measurement positions. Based on the above, the moving speed of the substrate is calculated, and the printing agent is printed while moving the substrate at the moving speed between two predetermined measurement positions.

The present invention is characterized in that the first measurement position is the position of the printing agent printed first, and the nth measurement position is the position of the printing agent printed last.

In the off-contact printing method of the present invention, a mask having an opening for printing a printing agent on a plurality of electrodes formed on a substrate, and the substrate is placed so as to be movable below the mask. A step of placing the substrate on the stage using a printing apparatus having a stage and a squeegee that prints the printing agent supplied on the mask onto the electrodes from the opening; A step of setting a gap between the substrate and the substrate at a predetermined interval, a printing step of moving the squeegee along the mask to print the printing agent supplied on the mask onto the electrode from the opening, and a step of removing the substrate from the stage In an off-contact printing method in which a printing agent is printed on a substrate by a printing method including: a printing process is performed during printing agent printing so as to reduce a deviation between a position of the printing agent to be printed and a position of the electrode. Characterized in that it comprises an operation for moving the plate in the horizontal direction.

The present invention relates to a step of measuring the coordinates of the printing agent printed from the opening of the mask and the coordinates of the electrode of the substrate, and the movement of moving the substrate in the horizontal direction based on the shift amount between the coordinates of the electrode and the coordinates of the printing agent. The method includes a step of calculating an amount and a moving speed, and a step of moving the substrate in a horizontal direction during printing agent printing based on the moving amount and the moving speed.

The present invention is characterized by a printing apparatus using the above-described off-contact printing method.

The present invention is characterized by a ball mounting apparatus using the above-described off-contact printing method.

  The off-contact printing method of the present invention moves the substrate during flux printing based on the amount of deviation between the flux printed on the substrate and the electrode, so that it is possible to correct all differences including mask and substrate manufacturing errors. There is.

  The off-contact printing method of the present invention is suitable for precision printing of a long substrate in which a manufacturing error between the substrate and the mask becomes large. It is particularly suitable for high-precision printing of long objects exceeding 20 cm and further objects exceeding 1 m.

  The off-contact printing method of the present invention can be used for printing liquid crystal displays, plasma displays, organic EL displays and the like, masks for them, conductive paste, solar cell electrodes, etc. Is effective for printing organic EL agents and the like, and by using this off-contact printing method, a large precision printing apparatus and a large micro solder ball mounting apparatus can be put into practical use.

FIG. 1 is a plan view for explaining the ball mounting apparatus. FIG. 2 is an explanatory diagram of a front view of the printing apparatus. 3A and 3B are diagrams for explaining the squeegee unit, in which FIG. 3A is a front view, FIG. 3B is a plan view, and FIG. 3C is a side view. 4A and 4B are explanatory views of the mask unit, in which FIG. 4A is a plan view, FIG. 4B is an AA cross-sectional view, and FIG. 4C is an enlarged view of the opening group 42. FIG. 5 is an explanatory view of the substrate and is a plan view. FIG. 6 is an enlarged view of a chip connection region disposed on the substrate. FIG. 7 is a diagram for explaining off-contact printing. FIG. 8 is a diagram for explaining the state of flux printing position deviation. FIG. 9 is a flowchart for calculating the flux printing position deviation. FIG. 10 is a flowchart for explaining a printing method for correcting misregistration. FIG. 11 is a diagram for explaining a step of moving the substrate in order to correct the printing position deviation.

  According to the present invention, it is possible to collectively correct a printing position deviation inherent in off-contact printing and a printing position deviation of a flack caused by a manufacturing error between the substrate and the mask by moving the substrate.

  FIG. 1 is a plan view of a solder ball mounting apparatus 1 including a printing apparatus 7 of the present invention. The ball mounting device 1 is a device that mounts solder balls 48 on the electrodes 41 of the substrate 19, and transports the substrate among the substrate loader / unloader 2, the loader / unloader 2, the pre-aligner 4, and the stage 5. A robot 3, a pre-aligner 4 for roughly adjusting the position and direction of the substrate, a stage 5 moving on the X rail 10 between the pressing device 6, the printing device 7 and the ball transfer device 9, and a substrate on the stage 5 Are pressed, flattened by a pressing device 6, a printing device 7 for printing flux on the substrate, and a ball transfer device 9 for transferring solder balls to the substrate on which the flux is printed.

  The substrate 19 is taken out by the transfer robot 3 from the loader / unloader 2 storing the substrate on which the solder balls are not mounted, and is placed on the pre-aligner 4. After roughly adjusting the direction and position of the substrate, the substrate is mounted on the stage 5 and pressed by the pressing device 6 against the substrate mounting table 18 and set in a flattened state.

Two cameras 34 are disposed downward between the printing device 7 and the ball transfer device 9. These cameras are measuring instruments for measuring the reference position mark 39 of the substrate on the stage and aligning with the mask. When the stage on which the substrate is placed moves on the X rail 10, the stage cannot be detected because the camera cannot detect the reference position mark unless the reference position mark provided on the substrate is within the field of view of the camera 34. In order to prevent this stray, the pre-aligner aligns so that the reference position mark on the substrate is within the field of view of the camera while the stage is moving.

In FIG. 1, 3a is a hand of the robot 3 for transporting the substrate 19, 8 is a lower surface cleaning device for the printing mask 37, 12 is a frame of the device, 14 is a Y rail of the stage 5, and 37 is a printing mask.

The ball mounting device 9 includes two sets of ball transfer heads 49 and a transfer mask 50. The ball transfer head 49 is integrally provided with a ball supply device, and moves on the transfer mask 50 while holding the solder balls supplied from the ball supply device onto the transfer mask 50. The solder ball is transferred onto the substrate from an opening provided in the transfer mask 50.

  FIG. 2 is a front view for explaining the printing apparatus 7 used in the present invention. The printing device 7 includes a squeegee unit 11, a mask unit 44, and a frame 12. The squeegee unit 11 will be described with reference to FIG. The mask unit 44 includes the mask frame 13 and the printing mask 37, and is fixed to the frame 12 through the attachment member 25 so as to be detachable, and will be described in detail with reference to FIG. A stage 5 is disposed below the printing apparatus 7 so as to be movable by an X rail 10 and a Y rail 14. Since the drawings are complicated, the frame 20, the substrate guide 24, and the mask frame guide are shown in cross section.

The stage 5 is assembled on the base plate 15 and can freely move on the X rail 10 and the Y rail 14 (in a horizontal plane). On the base plate 15, the θ-axis motor 16 and the Z-axis drive device 17 are disposed independently. The frame 20 is disposed at the outer edge of the substrate mounting table 18 and at the upper end of the Z-axis drive device 17 so as to be vertically movable. The θ-axis motor 16 rotates the substrate mounting table 18 in the horizontal plane, and corrects the angular deviation in the horizontal plane between the substrate 19 mounted on the substrate mounting table and the mask. Then, four Z-axis drive devices 21 and four lift rods 22 are disposed via an attachment member 23 disposed on the top of the θ-axis motor.

A guide hole 22 a that allows the lift bar 22 to move up and down is formed in the substrate platform 18. The lift bar is fixed to the mounting member 23, but has a structure that can be moved up and down relatively with respect to the substrate mounting table 18 by moving the substrate mounting table 18 up and down by the Z-axis moving device 21. This relative vertical movement allows the hand of the transfer robot 3 (the tip of the arm 3 a) to enter between the substrate 19 and the substrate mounting table 18 when the substrate is detached from the substrate mounting table 18. More specifically, the substrate 19 placed on the hand of the transport robot 3 from the loader is placed on the lift bar in a state where the lift bar 22 protrudes above the substrate platform 18. Thereafter, the hand of the transfer robot returns to the retracted position, and the substrate mounting table 18 is raised by the Z-axis drive device 21, that is, the lift bar 22 moves relatively below the substrate mounting table 18, so that the substrate is mounted on the substrate. It is placed on the table. Subsequently, the substrate is fixed to the substrate mounting table by suction from a decompression hole (not shown) provided on the substrate mounting table. The process of removing the substrate from the substrate mounting table is the reverse of the above process. FIG. 2 shows a state in which the stage in which the substrate is fixed to the substrate mounting base under reduced pressure in this way has moved downward in the printing apparatus 7. When the warpage of the substrate 19 is large, the substrate is sucked under reduced pressure while pressing the substrate 19 with the pressing device 6.

The frame 20 is disposed on the upper portion of the Z-axis drive device 17 and constitutes the outer peripheral portion of the upper surface of the stage 5. The substrate guide 24 is disposed on the outer periphery of the substrate mounting table 18 and is fixed so as to be movable up and down corresponding to the thickness of the substrate 18. The substrate 19 can be moved up and down independently by the Z-axis driving device 21 and the frame 20 can be independently moved by the Z-axis driving device 17. In order to remove the substrate 19 from the substrate mounting table 18, when the substrate mounting table is lowered by the Z-axis driving device 21, the lift bar 22 is fixed to the mounting member 23 and does not move up and down. There is a gap (not shown) between them. A hand (not shown) of the transfer robot 3 is placed in this gap, and the substrate is placed on the hand and moved.

3A and 3B are explanatory diagrams of the squeegee unit 11, in which FIG. 3A is a plan view, FIG. 3B is a front view, and FIG. 3C is a side view. The squeegee unit 11 is composed of two sets of squeegees, and the interval between them can be adjusted. The squeegee unit moves on the Y rail 32 fixed to the frame 12 of the apparatus. The Y rail 32 is composed of a servo motor 33 and a ball screw (not shown) so that the moving speed can be controlled with high accuracy.

The air cylinder 26 that moves the squeegee 31 up and down is fixed to an attachment plate 29, and the squeegee 31 is attached to the lower end of the cylinder rod via a squeegee attachment member 30. In order to increase the parallelism of the squeegee 31, guide rods 28 are disposed on both sides of the air cylinder 26. The guide rod 28 is movably attached to the squeegee attachment member 30 via bearings (not shown) of the attachment plate 45 and the attachment plate 29. There are two squeegees 31, and reciprocal printing is possible. And as shown in FIG.3 (c), the two squeegees 31 can be moved up and down independently. The squeegee 31 moves the flux 36 in the left-right direction and prints the flux 36. The right squeegee not printing the flux is evacuated to the upper standby position. The material of the squeegee 31 is hard rubber or metal. A part of the mask 37 is shown by omitting the mask opening.

  FIG. 4 shows a mask unit 44 for flux printing. (A) is a plan view of the mask unit 44, (b) is an AA sectional view of (a), and (c) is an example of an enlarged view of the opening group 42 corresponding to the chip connection region. The mask 37 is a metal thin film in which an opening 43 for printing the flux 36 is formed by additive (electroforming), chemical etching, laser drilling, or the like, and is also called a metal mask. Since the thickness of the mask is extremely thin at around 1/3 to 1/2 of the opening diameter, it is easy to bend. In order to prevent bending and increase the accuracy of flux printing, the mask is fixed to the mask frame 13 in a state where tension is applied via an adhesive sheet 37a and the like. The mask unit 44 with the mask on the mask frame is inserted into the mask frame guide 25 and then clamped so as not to move.

  In FIG. 4A, A is the first opening 43 where printing starts, E is the last opening 43 where printing ends, and C is the opening 43 located between A and E. Depending on the design of the substrate electrode, there may be no opening corresponding to C, but it will be described as being present. Printing misalignment also occurs on the mask surface perpendicular to the AA section (perpendicular to the printing direction), but with this method, correction in the direction perpendicular to the printing direction cannot be made. The direction is preferred.

  Two or more mask position reference marks 38 are formed on the back surface of the mask. These reference position marks 38 are arranged diagonally as shown in FIG. 4A, arranged parallel to the X rail 10, and arranged parallel to the Y rail 10. There is. The position (coordinates) of the reference position mark 38 is measured by the camera 35 mounted on the stage 5 and stored in the memory when the mask unit 44 is fixed to the printing apparatus 7.

As shown in FIG. 4B, the adhesive sheet 37 a fixes the outer periphery of the mask 37 while applying tension to the lower surface of the mask frame 13. These boundaries are illustrated by broken lines in FIG.

Since the diameter of the opening 43 formed in the mask 37 is as fine as 60 μm, each of them cannot be shown in the figure. Therefore, a region where the opening is formed corresponding to the electrode of one semiconductor chip (opening group 42) is formed. It displays with a rectangle and the enlarged view is shown in FIG.4 (c). The opening 43 shown in this figure is drawn larger than the actual size for easy viewing. Therefore, the number of openings 43 is greatly reduced. In the mask 37, opening groups 42 are arranged in a 5 × 7 matrix.

The direction of flux printing is indicated by arrows. However, the moving direction of the squeegee 31 can be moved in the direction opposite to the arrow, and the direction of flux printing may be the opposite direction of the arrow. Therefore, in the present invention, the printing direction includes a reverse direction that is 180 degrees different from the direction of the arrow.

FIG. 5 is a plan view for explaining the substrate 19 having a plurality of chip connection regions 42. 5 is different from FIG. The chip connection region 42 is formed in a 5 × 7 array and corresponds to the opening group 42 of the transfer mask 37. Two reference position marks 39 on the substrate are formed on the diagonal line. These reference position marks may be provided in parallel to the side of the substrate 19 or four. The chip connection area 42 is displayed in a rectangular shape with electrodes omitted.

B on the substrate 19 is an electrode that first prints the flux at the position where the opening of A on the mask 37 in FIG. 4 prints the flux. However, the flux is not always printed on B due to the printing position shift. D is an electrode at a position corresponding to C in the mask of FIG. 4 in the center of the chip connection region 40 arranged in a row of seven. F is an electrode to be printed last, and is an electrode at a position corresponding to E of the mask in FIG.

FIG. 6 is an enlarged plan view of one chip connection region. 40 is a plan view of one chip, and the electrode 41 has a one-to-one correspondence with the opening 43 shown in FIG. 4C, but it is larger than the actual size for easy viewing. . There may be no surrounding rectangular frame indicating the chip.

FIG. 7 corresponds to the AA cross section of FIG. 4A, and is a diagram for explaining the displacement of the printing position at the time of off-contact printing. In other words, FIG. 7 is a cross-sectional view in which the central portion of the mask unit being printed is cut perpendicularly to the moving direction of the squeegee. The dimensional ratio such as aspect ratio is different from the actual one. Furthermore, the mask 37 does not show an opening for printing flux, and the substrate 19 does not show the electrode 41 and the flux printed on the electrode. In addition, when the squeegee is lowered until the mask comes into contact with the substrate, the tip of the squeegee receives a different force in the front-rear direction due to the mask, but is illustrated as falling vertically without bending. However, since the printing position of the flux is measured according to the present invention, reproducible squeegee deformation does not cause a problem with respect to prevention of printing misalignment.

The mask 37 is affixed to the mask frame 13 with a tension applied. The mask frame 13 is fixed to the gantry 12 with a clamper (not shown) via the mask frame guide 25 (see FIG. 2). The substrate 19 is adsorbed under reduced pressure on the substrate mounting table 18 of the stage 5. Since the stage 5 is movably disposed on the Y rail, the substrate 19 can freely move in the direction opposite to the direction of the arrow. Further, the moving direction of the stage 5 may be an X-axis direction using an X rail, and includes an arbitrary horizontal direction. Furthermore, since the substrate 19 can be moved up and down by the Z-axis drive device 21, it can also be moved up and down during the flux printing. Thus, in the present invention, the direction in which the substrate 19 moves during flux printing may be a combination of the horizontal direction and the vertical direction.

The deformation of the mask 19 can be expressed by a polynomial including Young's modulus and Poisson's ratio. It is also possible to calculate the deformation quantitatively using the finite element method. As can be easily understood from these calculation results, the squeegee 31 has a width even when the positional deviation of the printed flux is measured. The flux printing position is shifted without the same deformation. However, in the first embodiment, printing misalignment will be described at the center of the squeegee.

When the squeegee 31 is pushed down until the mask 37 comes into contact with the substrate 19, the angles formed by the mask 37 and the substrate 19 are left α and right β. When the squeegee 31 is on the left side of the central portion C of the mask 37, α> β. The printing position is shifted due to this angle difference.

FIG. 7 illustrates the case where the mask and substrate are manufactured to the same dimensions and the substrate is accurately aligned with the mask. In FIG. 7, the mask 37 in a state where the squeegee 31 is not pressing the mask is indicated by a dotted line. The substrate 19, the squeegee 31, and the flux 47 are hatched for clarity. The flux printed from the opening A on the mask indicated by the dotted line is printed at the position G of the substrate. G is shifted leftward from the electrode B immediately below the opening A. When the squeegee 31 moves to the opening C, which is the center of the mask 37, α = β, and H is directly below C. That is, the flux printed from the opening C is printed on the electrode D without being displaced. Next, the flux that is printed from the opening E is printed with a delay, and as a result, the flux is shifted to the right side from the electrode F (just below the opening E) and printed on I.
When the mask 37 is pushed down by the squeegee 31, the mask is fixed to the mask frame 13 and thus extends. The mask stretches while shifting the relative positional relationship with the squeegee so that the stretch rate is the same on the left and right of the pressing point of the squeegee (in an ideal case, it differs slightly because there is actually friction). Specifically, when α is larger than β, the β-side mask passes under the squeegee and moves to the α side.

FIG. 8 is a diagram for explaining the printing position deviation of the flux in more detail. As in FIG. 7, the case where the mask and the substrate are manufactured to the same size and the substrate is accurately aligned with the mask, and the mask has only five openings in a line in the printing direction (arrow) will be described as an example. To do. Accordingly, the number of electrodes on the substrate corresponding to that is five in one row. In order to avoid the complexity of the drawing, the opening of the mask, the electrode of the substrate, and the diameter of the printed flux are described as being the same size, and each is indicated by hatching. The opening is a blank without hatching, the electrode is 45 ° hatched, and the printed flux is 135 ° hatched.
A, C, and E are the openings 43 of the mask. B, D and F are electrodes 41. G, H and I are printed fluxes. Furthermore, Ac, Cc and Ec are the centers of the openings, Bc, Dc and Fc are the centers of the electrodes, and Gc, Hc and Ic are the centers of the printed flux.
The misregistration is displayed as a vector from the center of the electrode to the center of the flux at the coordinates shown in the lower left corner of FIG. 8, and is plotted assuming that there is no misregistration in the printing direction.

FIG. 8A shows the opening of the mask. As in FIG. 7, the moving direction of the squeegee is shown in the direction (y direction) rotated 90 degrees in FIG. FIG. 8B shows the electrodes of the substrate. Since the mask and the substrate are perfectly aligned, the electrode centers Bc, Dc and Fc are directly under the aperture centers Ac, Cc and Ec. FIG. 8C shows a state where the flux is printed on the substrate. The area where the flux is printed on the substrate is indicated by cross hatching. FIG. 8D shows only the printed flux. Symmetrical and no misalignment at the center.

Next, measurement of the flux printing position deviation amount will be described. Since the printed flux plane is substantially circular, the printed flux is image-recognized, the shape of the printed flux is processed as a circle, and the center (coordinates) of the printed flux is calculated. The flux is printed and measured by the camera 34 that measures the reference position mark on the substrate. Similarly, the center coordinates of the electrode are measured. When measuring the center coordinates visually, the substrate is removed from the stage and a tool microscope is used, and the center mark is read by combining the circular mark provided at the center of the field of view of the tool microscope with the outer shape of the flux. On the other hand, the center coordinates of the electrodes are similarly determined by defining the outer shape of the electrodes.

FIG. 8A shows the opening of the mask, the opening at the left end (printing start end) is A, the center is C, and the right end (printing end) is E. The corresponding electrodes in FIG. 8B are B at the left end, D at the center, and F at the right end. FIG. 8C shows a state where the flux is printed. The flux printed at the opening C is printed on the electrode D. However, the center Gc of the flux printed at the opening A is shifted a distance a to the left from the center Bc of the electrode. The center Ic of the flux printed at the opening E is shifted to the right by the distance b from the center Fc of the electrode.

“A” and “b” are vectors having a length and a direction from the center of the electrode, and are displayed as a (vector) and b (vector) when handled as vectors. When simply a and b are displayed, only the length is indicated. When adding or subtracting the length, a negative sign is assigned when the center of the flux is shifted to the left from the center of the electrode, and a positive sign is added when the center is shifted to the right.
When the distance between the centers of the electrodes B and F is Le and the center distance between the printed flux G and flux I is Lf, Lf−Le = b (vector) −a (vector) = b + a. This equation is not limited to the above conditions and can be generalized.

On the other hand, when the concept of moving the substrate during printing is simply expressed, when the distance Lf is larger than the distance Le, the substrate is moved in the printing direction to increase the apparent Le. On the other hand, when Le is larger than Lf, the substrate is moved in the direction opposite to the printing direction to reduce the apparent Le. Further, as a method for preventing printing deviation at the start of printing, printing is started after moving by the amount of positional deviation of the flux printed first.

Next, FIG. 9 will be described with reference to FIG. 8 with respect to a method for calculating a correction value for the printing position deviation (a movement amount for moving the substrate before the first flux printing and a moving speed for moving the substrate during printing). It explains using. FIG. 9 is a flowchart for calculating the misalignment of flux printing.
In step 1 (S1), the substrate is placed on the stage and fixed by suction under reduced pressure. If the substrate is greatly warped, the substrate is pressed and flattened and sucked under reduced pressure.
In step 2 (S2), the mask and the substrate are aligned using the measurement data of the coordinates of the reference position mark of the mask and the coordinates of the reference position mark of the substrate.
Step 3 (S3) sets the gap between the substrate and the mask to 2 mm.
Step 4 (S4) prints the flux on the substrate.
In step 5, the coordinates of the center Bc of the electrode of the substrate to be printed first and the center Gc of the flux printed corresponding to the electrode are measured. Next, the coordinates of the center Fc of the electrode of the substrate to be printed last and the center Ic of the flux printed corresponding to the electrode are measured.

Step 6 (S6) is based on the measurement data.
(1)
A deviation a (vector) from the center Bc of the first electrode to the center Gc of the flux printed first is calculated.
(2)
The distance Le between the center Bc of the first electrode and the center Fc of the electrode printed last is calculated.
(3)
A slip b (vector) from the center Fc of the last electrode to the center Ic of the flux printed last is calculated.

Next, the coordinates of the movement start of the substrate are calculated using the calculation data. In order to print the flux G to be printed first without shifting on the electrode B to be printed first, the coordinates where the substrate is moved by a (vector) are set as the printing start coordinates of the flux. However, in the present invention, the direction of the positional deviation vector is the direction of the center of the printed flux from the center of the electrode. When corresponding to the coordinates described in the lower left corner of FIG. 8, a is a negative value and b is a positive value. Hereinafter, the distance between the electrode and the printed flux is the distance from the electrode to the flux, and is calculated by adding plus and minus signs depending on the direction.

Next, the coordinates for ending the movement of the substrate are calculated. If the substrate is not moved to match the first printed flux to the electrode, the last printed flux I can be printed over the last printed electrode F by moving the substrate by b (vector). .

Step 7 calculates the moving direction and moving speed of the substrate. The distance Lf between the first printed flux center Gc and the last printed flux center Ic, and the distance Le between the first printed electrode center Bc and the last printed electrode center Fc. The difference c (vector) is b (vector) -a (vector). Therefore, after the substrate is moved by a (vector) and flux printing is started, the substrate is moved by c (vector), so that the last printed flux center Ic becomes the last printed electrode. Consistent with central Fc.

Here, if the moving speed of the squeegee 31 is u, the time t during which the squeegee moves from Bc to Fc is t = Lf / u. Accordingly, by moving the substrate by c (vector) within the time t, the electrode center Fc and the flux center Ic coincide. For this reason, in order to make the electrode F and the flux I coincide with each other, the moving speed v of the substrate may be moved at v = c * u / Lf. Although the movement of the substrate may be stopped when the printing of the electrode F is completed, it may be stopped after a few seconds with a margin.

Next, a flux printing method using the misregistration correction value will be described with reference to FIG. FIG. 10 is a flowchart of printing using the above-described misregistration correction value. The substrate to be used is another substrate manufactured under the same conditions as the substrate used for calculating the correction value of the positional deviation. Note that. The substrate used for calculating the correction value of the positional deviation may be used after cleaning.
Step 1 (S1) places the substrate on the stage.
Step 2 (S2) aligns the substrate with the mask. This corresponds to FIG. In this state, the flux printed first is shifted by a (vector).
In step 3 (S3), the gap between the substrate and the mask is set to 2 mm (the same as the condition for calculating the positional deviation correction value).
Step 4 (S4) supplies flux onto the mask.

In step 5 (S5), the substrate is moved by a (vector) in the printing direction, and the positional deviation of the flux printed first is corrected. This corresponds to FIG. Note that the substrate is moved by moving the stage.
In step 6 (S6), the movement of the squeegee is started from a position where the opening to be printed first is not reached.
Step 7 (S7) starts moving the substrate at a predetermined speed v (c * u / Lf) when the squeegee reaches the center of the opening to be printed first. This corresponds to FIG.
Step 8 (S8) stops the movement of the substrate when the squeegee reaches the center of the opening to be printed last (corresponding to FIG. 11D). When the squeegee reaches the center of the opening to be printed last, it is set as time t after the movement starts. It is not absolutely necessary to stop the movement of the substrate, and the movement may be continued until the end of the flux printing.
Step 9 (S9) raises the squeegee after completion of the flux printing.
In step 10 (S10), the printed substrate is removed from the substrate mounting table, and is sent to the next step such as a ball mounting step.

FIG. 11 shows the positional relationship between the mask 37 and the substrate 19 in the method of correcting the printing position deviation by moving the substrate. The mask 37 is fixed, and the substrate 19 moves on the stage. On the mask 37, an opening A to be printed first and an opening E to be printed last are displayed in order to explain the positional relationship with the position of the substrate. The flux printing direction (squeegee movement direction) is from left to right. The substrate 19 displays the first printed electrode B and the last printed electrode F, and further displays the first printed flux G and the last printed flux I.
(A) is a position when a mask and a board | substrate are match | combined with the reference position mark. In addition, although the code | symbol at the time of the measurement of printing position shift is not attached | subjected to the board | substrate, it has attached | subjected so that a positional relationship may be understood easily. The flux G is shifted from the electrode B to the left (minus) a. Further, the flux I is shifted to the right (plus) b from the electrode F. The cap of the substrate 19 and the mask 37 is shown enlarged at 2 mm.

(B) shows a state in which the electrode B printed first is moved so as to overlap the flux G printed in the opening A. Since the first printed electrode B is on the right side of G, in order to print the first printed flux on the first printed electrode B, the substrate 19 is placed on the left (opposite to the printing direction). Move by a. For this reason, all the electrodes move to the left by a. In this state, flux printing is started.
(C) shows the state which is moving the board | substrate to the right (printing direction) with the moving speed v, printing a flux.
(D) is a state in which the substrate 19 is moved to the right side by a distance (a + b) and the electrode F to be printed last is overlapped with the printed flux I by the opening E to be printed last. Thereafter, the substrate 19 may move or stop.

The printing position deviation caused by the gap between the substrate and the mask is not linear with respect to the position of the substrate, and the error of linear interpolation increases unless the correction interval is reduced. The positional deviation of the flux printing is generally large at the printing start point and the printing end point, and is small at the intermediate portion between them. On the other hand, the mask and substrate manufacturing errors can often be linearly interpolated.
In the first embodiment, the flux printed at the beginning and the end is printed without deviation on a predetermined electrode. However, the flux printed on the intermediate electrode may be small but shifted due to linear interpolation. .

The second embodiment is a method of increasing the interpolation accuracy at the intermediate electrode by shortening the interval for interpolating the printing position deviation. Let n (an integer greater than or equal to 3) measurement points for measuring the printing position deviation with respect to the substrate when the flux is printed in the printing direction, and the intervals between adjacent measurement points are equal intervals so that they can be easily corrected. Descriptions similar to those in Example 1 are omitted. The case of n = 2 is Example 1.
First, measurement and calculation for eliminating positional deviation are executed. In order to actually measure the printing deviation of the flux, after aligning the substrate and the mask, the flux is printed on the substrate. The center coordinate of the kth electrode is e (k), and the center coordinate of the kth printed flux is f (k). The k-th printing position deviation amount is a (k) (vector), and the (k + 1) -th printing position deviation amount is a (k + 1) (vector). Let L (k) be the interval between f (k + 1) and f (k). Next, the moving speed u of the squeegee is set, and v (k) (vector) and moving time t (k), which are the moving speed of the substrate for correcting the positional deviation amount, are calculated in the same manner as in the first embodiment. To do. However, k is an integer of 1 to (n-1). Furthermore, the coordinates are one-dimensional and the printing direction.

(Equation 1)
a (k) = e (k) −f (k)

(Equation 2)
L (k) = f (k + 1) −f (k)

(Equation 3)
t (k) = L (k) / u

(Equation 4)
v (k) = a (k) / t (k) (= a (k) * u / L (k))

Next, a printing method in which the positional deviation is corrected will be described.
First, in order to eliminate the positional deviation at the position where printing starts, the substrate is moved by a (1) (vector) and printing is started.
Next, a method for moving the substrate during printing will be described.
First, with k = 1, the substrate is moved at a speed v (1) (vector) for a time t (1). Thereafter, k is incremented by 1 and the substrate is moved at the speed v (k) (vector) for the time t (k). When k = n−1, the movement of the substrate is stopped. Stop printing after moving the squeegee. Note that the substrate may be moved even after the printing is completed, as in the first embodiment. By this method, the interpolation accuracy of the positional deviation can be increased.

In the first embodiment and the second embodiment, the basic method for correcting printing misalignment has been described. Example 3 is a modified example thereof.
In FIG. 5, the electrode to be printed first is indicated by one point B. However, when there are conditions such as difficulty in measurement and unstable printing, the electrodes are arranged in the central direction of the substrate. The printing position deviation may be corrected by measuring the printing deviation of the electrode B1. The same applies to the last printed electrode, and the printing deviation of the electrode F1 arranged in the center direction of the substrate may be measured. An example of the third embodiment is to measure an arbitrary electrode in the printing direction, calculate the center coordinates of the flux printed corresponding to the electrode, and correct the printing deviation. In this embodiment, it is possible to improve the printing misalignment correction accuracy.

Further, in FIG. 5, the electrode B to be printed first is one point with respect to the direction perpendicular to the printing direction, but a plurality of points may be measured. In addition to B, B2 and B3 are added as electrodes to be printed first, and the center coordinates of the flux printed corresponding to them are measured. In addition to F, F2 and F3 are added as electrodes to be printed last, and an average value thereof is used to correct printing misalignment. The calculation of the moving speed and moving time of the substrate is the same as in the first and second embodiments. In this embodiment, it is possible to improve the printing misalignment correction accuracy.

In the present invention, the flux comprises rosin, a rosin derivative, an activator, a thixotropic agent, a solvent, etc., and the activator comprises a carboxylic acid added with a hydrogen halide salt. Furthermore, in the present invention, the flux is used to explain the invention. However, in addition to cream solder, conductive paste, non-conductive paste, etc., other things including other organic liquids and organic liquids containing inorganic substances are printed. It is defined as an agent.

As described above, there are a wide variety of methods for actually measuring the amount of printing misregistration, a method for calculating misregistration, etc., and a wide variety of printing agents. It is obvious that the present invention is not limited to a method for actually measuring the amount of printing misalignment, a method for calculating misregistration, and a printing agent to a specific substance. The present invention is characterized in that the printing position deviation is corrected by moving the substrate based on the actually measured printing position deviation amount. Further, although the number of times of measurement of the printing position deviation amount has been described as one, it is also included in the present invention to reduce the measurement error by measuring the printing position deviation amount a plurality of times. Further, in the present invention, the correction value of the printing deviation includes a movement amount of the substrate for correcting the position to be printed first, and a moving speed for moving the substrate at a predetermined speed while printing.

In the present invention, the gap between the substrate and the mask is not limited to 2 mm, and may be 0.5 to 3 mm. Although the diameter of the opening 43 formed in the mask 37 is described as 60 μm in the embodiment, the diameter of the opening may be 20 to 300 μm. or. The types of the substrate 19 are a wafer and a printed wiring board. Further, the lift bars 22 may be increased in number and the cross-sectional area of the lift bars may be increased in order to prevent deformation and damage of the substrate when the lift rod pushes up the substrate relatively. Furthermore. In order to shorten the ball transfer time, two or more ball transfer heads 49 may be arranged in a matrix, for example, four in the horizontal direction and two in the vertical (transfer direction). In addition, two stages 5 for the printing device 7 and the solder ball transfer device 9 may be used.

In the present invention, the printing device refers to a substrate mounting table on which a substrate is mounted, a driving device that moves the substrate in the XYZθ direction, a frame that holds the mask, and a squeegee that prints the printing agent on the substrate through the mask. And a drive mechanism that moves the squeegee in the printing direction and the vertical direction.

In the present invention, the ball mounting device includes a substrate loader / unloader, a device that prints the flux supplied onto the mask onto the substrate, and a ball transfer device that transfers the solder balls supplied onto the mask onto the substrate. Refers to the device.

The off-contact printing method of the present invention is applicable to cream solder printing, color filter printing, organic EL printing, inorganic EL printing, conductive paste printing, non-conductive paste printing, etc., in addition to ball mounting flux printing. It is valid. The present invention has a special effect on a mask and a substrate that are long and have large manufacturing errors in dimensions. Further, this off-contact printing method is indispensable for ball mounting on which a small solder ball having a diameter of 30 to 80 μm is mounted. By using this off-contact printing method, it is possible to put the ball mounting on a small ball into practical use. .

DESCRIPTION OF SYMBOLS 1 Ball mounting device 2 Loader / unloader device 3 Transfer robot 3a Hand 4 Pre-aligner 5 Stage 6 Press device 7 Printing device 8 Mask cleaning device 9 Ball transfer device 10 X rail 11 Squeegee unit 12 Frame 13 Mask frame 14 Y rail 15 Base Plate 16 θ-axis motor 17 Z-axis driving device 18 Substrate mounting table 19 Substrate 20 Frame 21 Z-axis driving device 22 Lift bar 22a Guide hole 23 Mounting member 24 Substrate guide 25 Mask frame guide 26 Air cylinder 27 Cylinder rod 28 Guide rod 29 Mounting Plate 30 Squeegee mounting member 31 Squeegee 32 Y rail 33 Servo motor 34 Camera (downward)
35 Camera (upward)
36 flux 37 printing mask 38 mask reference position mark 39 substrate reference position mark 40 chip connection area 41 electrode 42 mask opening group 43 opening 44 mask unit 45 mounting plate 46 support 47 flux 48 solder ball 49 ball transfer head 50 transfer Mask

Claims (7)

The step of mounting the substrate on the stage, the step of aligning the substrate with the mask, the step of setting the distance between the substrate and the mask to a predetermined distance, the step of supplying the printing agent onto the mask, and the mask by lowering the squeegee A part of the squeegee abuts the substrate, a squeegee is moved along the substrate, and a printing process is performed on the substrate through an opening provided in the mask, and the squeegee is raised after the printing process. In an off-contact printing method comprising a step of separating the mask from the substrate and a step of sending the substrate to the next step,
A deviation amount measuring step of measuring a deviation amount between the printed printing agent and the electrode using the first substrate;
Moving the second substrate based on the amount of misalignment to reduce the misalignment between the first printed printing agent and the first printed electrode on the second substrate;
An off-contact printing method comprising: printing a printing agent on a second substrate while moving the second substrate in the movement direction of the squeegee based on the shift amount. In the deviation amount measuring step, the measurement position of the deviation amount is considerably different from the first measurement position to the nth (n is an integer of 2 or more) measurement position, based on the deviation amount between two predetermined measurement positions. 2. The off-contact printing method according to claim 1, wherein the printing agent is printed while the substrate is moved at a moving speed between two predetermined measurement positions. 3. The off-contact printing method according to claim 2, wherein the first measurement position is a position of the printing agent printed first, and the n-th measurement position is a position of the printing agent printed last. . A mask having an opening for printing a printing agent on a plurality of electrodes formed on the substrate, a stage placed on the substrate so as to be movable below the mask, and supplied onto the mask Using a printing apparatus having a squeegee that prints the printing agent on the electrodes from the openings, a step of placing the substrate on the stage, moving the substrate below the mask, and keeping the gap between the mask and the substrate at a predetermined interval In an off-contact printing method, including a setting step, a printing step of moving a squeegee to print a printing agent supplied on a mask onto an electrode from an opening, and a step of removing the substrate from the stage.
The printing process includes an operation of moving a substrate in a horizontal direction during printing agent printing in order to reduce a deviation between a printing agent position to be printed and an electrode position. 5. The printing method according to claim 4, wherein the step of measuring the coordinates of the printing agent printed from the opening of the mask and the coordinates of the electrode of the substrate and the amount of deviation between the coordinates of the electrode and the coordinates of the printing agent An off-contact printing method comprising: calculating a moving amount and a moving speed for moving in the horizontal direction; and moving the substrate in a horizontal direction during printing agent printing based on the moving speed. A printing apparatus using the off-contact printing method according to claim 1. A ball mounting apparatus using the off-contact printing method according to claim 1.