JP2008288515A - Solder ball printing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solder ball printing apparatus capable of forming bumps by efficiently and securely loading and printing solder balls of a microminiature size. <P>SOLUTION: The solder ball printing apparatus comprises a flux printing section for printing flux on electrode pads of a substrate 21, a solder-ball loading and printing section for supplying solder balls on the electrode pads on which the flux has been printed, and an inspection and repairing section for inspecting the printed status of the solder balls and carrying out repairing according to the failure status, wherein an inspection camera 15 is provided for observing the status after printing in the opening of a screen 20 of the printing section. Printing failure is judged from the status after printing observed in the opening of the screen 20 of the printing section by comparing the image taken by the inspection camera 15 and the image of a reference model recorded beforehand. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a screen printing apparatus, and more particularly to a solder ball printing apparatus for printing a solder ball on a substrate surface.

  In ball bump formation (diameter 80 to 100 μm) with a pitch of 180 to 150 μm, there is a printing method in which a solder ball is formed by reflowing cream solder after printing using a known high-precision screen printing apparatus. As an example of the screen printing apparatus, a substrate carry-in conveyor, a substrate carry-out conveyor, a table unit provided with a lifting mechanism, a mask having a transfer pattern as an opening, a squeegee, a squeegee lifting mechanism, and a squeegee head equipped with a horizontal movement mechanism, A control device for controlling these mechanisms is provided.

  After the board is carried into the device from the carry-in conveyor section, the board is temporarily positioned and fixed on the printing table section, and then the marks on both the board and the mask (screen) having an opening corresponding to the circuit pattern are recognized by the camera. Then, correct the position of both displacements, align the board with the screen, raise the printing table so that the board is in contact with the screen, and apply cream solder to the opening of the screen while making the screen contact the board with a squeegee. The paste is transferred onto the substrate by lowering the table and separating the screen from the screen (separating the plate), and then printing is performed by unloading the substrate from the apparatus.

  Also known is a ball transfer method in which solder balls are formed by transferring solder balls into jigs that have been drilled with high precision and finely aligned, transferred to a substrate directly at a predetermined pitch, and reflowed after placement. Yes.

  Further, according to Patent Document 1, there is a method of filling a predetermined opening with solder balls by swinging or vibrating the mask, or a method of heating after filling by translational movement of a brush or the like. Further, according to Patent Document 2, there is a method in which a solder ball is placed on a tray and adsorbed by a tube to be refilled into an electrode pad.

JP 2000-49183 A JP 2003-309139 A

  The printing method using cream solder has the advantage that the equipment cost is low and a large number of bumps can be formed at once, so that the throughput is high and the manufacturing cost is kept low. However, in the printing method, it is difficult to ensure the uniformity of the transfer volume, and there is a problem that the solder bump after reflow is pressed by the fluttering process to smooth the height, and the number of processes is large and the equipment cost is high. . In addition, when the finer process progresses to a pitch of 150 to 120 μm as the density of the device increases, there is a point that the printing yield is poor and the productivity is not good.

  On the other hand, with the solder ball transfer method, it is possible to form bumps with a stable height by ensuring the classification accuracy of the solder balls. However, since the solder balls are packed together by a robot using a high-precision solder ball adsorption jig, fine solder balls are used. There are problems such as an increase in tact in the case of an increase in cost and an increase in bump formation cost due to an increase in jig / equipment prices.

  Further, in the method of swinging or vibrating the screen according to Patent Document 1 and filling a predetermined opening with a solder ball, an adhesion phenomenon due to van Desworth force between particles or an adsorption phenomenon due to static electricity as the solder ball particle diameter decreases. Occurs and the mask opening cannot be filled. Similarly, there is a similar problem in filling by squeegee or brush translation.

  In the method of Patent Document 2, even if repair is possible, the possibility that the amount of residual flux is small is extremely high. If the solder wettability is poor at the time of batch reflow, the electrode may be melted even if the solder ball is melted. There is a risk that poor wetting may occur due to incomplete soldering to the pad.

  The object of the present invention is to form a large number of bumps at a time as in the printing method in forming a bump of ultra fine pitch, and to form a bump having a stable height as in the solder ball transfer method. Another object of the present invention is to provide a highly productive solder ball filling printing apparatus and bump forming method that enable efficient printing and filling at low cost and at high speed.

In order to achieve the above object, the present invention provides a flux printing unit for printing a flux on an electrode pad of a substrate, a solder ball filling / printing unit for supplying a solder ball on the electrode on which the flux is printed, and a solder. In the solder ball printing device consisting of an inspection / repair unit that inspects the state of the printed board of the ball and repairs it according to the defective state.
For flux positioning, imaging a positioning mark to align a screen with openings corresponding to a plurality of electrode pad positions, a table on which the substrate is placed and fixed, and the substrate and the screen. A camera, an inspection camera for observing the state of the screen opening after printing, a cleaning means for cleaning and removing the screen opening clogging or flux adhering stain on the back of the screen, an image captured by the inspection camera, A decision unit that compares the recorded image of the reference model to judge a printing defect, and a decision to decide whether to send the substrate to the process next or exclude it from the line based on the decision result of the decision unit Is provided with a printing defect generating means for generating a screen cleaning instruction.

  In addition, a filling unit is provided in the print head provided in the solder ball filling / printing section, and the filling unit is a ball case comprising a housing, a lid and a shib-like body, and a slit is provided at the lower part of the ball case with a gap between the shib-like body. And a vibrating means for supplying a solder ball to the slit-like body by changing the size of the opening provided in the shib-like body by vibrating the shib-like body via a support member. This is a configuration.

  According to the present invention, it is possible to improve productivity by processing a flux printing defect, which is a major cause of a solder ball filling defect, at an early stage in the leading process.

  In addition, according to the present invention, it is possible to improve the solder ball filling efficiency, to shorten the tact time and to fill and print the solder balls with a high filling rate, so that productivity can be improved.

  Furthermore, since the operation efficiency of each device from flux printing to solder ball filling to inspection / repair can be improved and tact time can be shortened, solder bump height accuracy is good, and a large amount of stable solder bumps can be made at low cost in a batch. It is possible to form with. In addition, the apparatus has a simple configuration, and the equipment cost can be kept low.

  Hereinafter, preferred embodiments of a printing apparatus and a bump forming method of the present invention will be described with reference to the drawings.

  FIG. 1 shows an outline of a printing process in the flux printing unit and the solder ball filling / printing unit. FIG. 1 (a) shows the flux printing process, and FIG. 1 (b) shows the state of solder ball filling / printing.

  In FIG. 1 (a), the flux is placed on the screen 20 provided with an opening in accordance with the shape of the electrode pad 22 provided in advance on the substrate 21, and the squeegee 3 is moved, so that the electrode pad 22 on the substrate 21. A predetermined amount of flux 23 is printed thereon.

  In this embodiment, the screen 20 is a screen for flux printing, and a metal screen manufactured by an additive method is used so as to ensure high-precision pattern position accuracy. As the squeegee 3, either a square squeegee, a sword squeegee or a flat squeegee is used. A screen gap, a printing pressure, and a squeegee speed corresponding to the viscosity and thixotropy of the flux 23 are set and a printing operation is performed. If the printed amount of the flux 23 is too small, the solder ball cannot be attached onto the electrode pad 22 when the solder ball 24 is filled.

  Further, during reflow, which is a post-process after solder ball printing, it becomes a cause of solder wetting failure, a solder bump having a beautiful shape cannot be formed, and it becomes a cause of poor solder bump height and insufficient solder connection strength. If the amount of the flux 23 is too large, the flux 23 may adhere to an opening or the like provided in the screen 20 for supplying the solder ball 24 onto the electrode pad 22 during filling and printing of the solder ball. If the flux 23 adheres to the screen opening, the solder ball 24 adheres to the opening of the screen, which causes a problem that the solder ball 24 cannot be transferred onto the electrode pad 22. Thus, flux printing is a process having the most important factor in solder ball filling quality.

  Next, as shown in FIG. 1B, the solder balls 24 are placed on the electrode pads 22 of the substrate 21 on which the flux 23 is printed by the solder ball filling / printing unit provided with the filling unit 60 (see FIG. 7). Fill and print. As the screen 20b for filling the solder balls 24 into the electrode pads 22, a metal screen manufactured by an additive method is used so as to ensure high-precision pattern position accuracy.

  The solder ball filling screen 20b is formed by placing the substrate so that the gap between the substrate 21 and the screen 20 is zero so that the solder ball 24 does not sink between the substrate 21 and the screen 20 to cause excessive ball defects. A magnetic material capable of attracting magnetic force from the magnet stage (printing table 10) is used.

  Further, when the printed substrate 21 is in close contact with the back surface of the screen 20b (the side in contact with the substrate 21), the flux 23 is made of resin or metal so that bleeding of the flux 23 does not adhere to the periphery of the screen opening. The minute support 20a is provided. As a result, an escape portion bleeding in the flux 23 is configured. Hereinafter, a combination of the screen 20b and the support 20a is referred to as a solder ball printing screen 20.

  Further, positioning marks (not shown) are provided at four corners of the substrate 21 in order to supply the solder balls 24 to the electrode pads 22 at predetermined positions with high accuracy. Corresponding to the positioning marks provided on the substrate 21 side, positioning marks are also provided on the screen 20 side. These positioning marks are visually recognized by the CCD camera 15 (see FIG. 4), and alignment is performed with high accuracy so that the positioning mark position provided on the screen 20 side coincides with the positioning mark position on the substrate 21 side. To do. In this embodiment, the alignment is performed by moving the printing table 10 on which the substrate 21 is mounted in the horizontal direction.

  When the alignment is completed, the distance between the substrate 21 and the screen 20 is reduced, the screen 20 is brought into contact with the substrate 21, the filling unit 60 is operated, and the solder balls 24 are printed with the flux 23 from the opening of the screen 20. This is supplied to the electrode pad 22 on the surface of the substrate 21. A slit-like body 63 is provided on the lower side of the filling unit 60 for supplying solder balls (see FIG. 7), and the solder ball 24 is pushed and rolled by rotating and advancing the filling unit 60 to rotate and vibrate. And filling the solder balls 24 into the screen openings.

  FIG. 2 shows an embodiment of a solder ball printing apparatus. The apparatus shown in this figure is an apparatus in which a flux printing unit, a solder ball filling / printing unit, and an inspection / repair unit are integrated. However, each part may be configured as a single device. In this apparatus, first, flux 23 is printed on each electrode pad 22 on the substrate by a flux printing unit (screen printing method). After that, solder is applied to the electrode pad via the flux at the solder ball filling / printing section through the transfer conveyor (from the slack printing section side is a carry-out conveyor and when viewed from the solder ball filling / printing section). Supply the ball.

  The part that differs greatly between the flux printing part and the solder ball filling / printing part is the print head part, the flux printing part has a squeegee structure, and the solder ball filling / printing part consists of a filling unit for supplying solder balls. Has been. The inspection / repair part has a dispenser type suction / supply head structure in the print head part. Further, since it is not necessary to use a screen in the inspection / repair section, there is no plate frame holder for attaching the screen.

  FIG. 3 shows a flowchart of bump formation in the present embodiment. After carrying in the substrate (STEP 1), a predetermined amount of flux is printed on the electrode pad (STEP 2). Next, the screen opening state after flux printing is inspected (STEP 3). In the case of NG by inspection, the substrate is carried out to the NG substrate stock portion, and cleaning is automatically performed by the block cleaning device 45 (STEP 4). Thereafter, the flux is supplied and replenished as necessary.

  In addition, the board which has become NG is made to stand by on the conveyor in the subsequent process together with the NG signal so as not to perform the processes after ball printing, and is discharged out of the line. By using an inline NG substrate stocker or the like, the magazine may be discharged in a batch. The NG substrate can be used again for flux printing after being washed in an off-line process.

  Next, solder ball filling / printing is performed (STEP 5). After the solder ball filling and printing, the solder ball filling state from above the screen into the screen opening is inspected before releasing the plate (STEP 6). As a result of the inspection, if there is an insufficiently filled portion, the solder ball filling / printing operation is executed again before releasing the plate (STEP 7). Thereby, the solder ball filling rate can be improved.

  When it becomes OK in STEP6, the plate separation is performed (STEP8). Next, the filling state is inspected (STEP 9) by the inspection / repair device after the solder ball filling. In the case of the filling status inspection NG, the solder balls are supplied again to the electrode pad portion at the NG point after supplying the flux (STEP 10). In the case of OK in the filling state inspection, the solder ball is remelted by the reflow device, and the solder bump is completed.

  FIG. 4 shows a schematic configuration of a screen printing apparatus (mainly a flux printing unit) in the present invention. FIG. 4A shows a configuration viewed from the front of the screen printing apparatus, and FIG. 4B shows a system configuration diagram. Further, FIGS. 5A and 5B are diagrams for explaining the operation of the screen printing apparatus.

  The main body frame 1 is provided with a plate frame receiver (not shown), and a mask is set on the plate frame receiver with a screen 20 having a printing pattern as an opening on the plate frame 20c (see FIG. 6). It is configured. In this figure, the print head 2 provided with the squeegee 3 is disposed above the screen 20.

  In the case of a flux printing unit, a urethane squeegee 3 is attached to the print head 2. In the case of a solder ball filling / printing unit, a filling unit 60 constituted by a slit-like body 63 or the like is attached to the print head 2 instead of the squeegee 3. The print head 2 is configured to be movable in the horizontal direction by the print head moving mechanism 6 and up and down by the print head lifting mechanism 4. By replacing the squeegee 3 with the filling unit 60, the filling unit 60 can be moved in the vertical direction by the print head lifting mechanism 4.

  Below the screen 20, a printing table 10 is provided so as to place and hold a substrate 21 that is a printing target so as to face the screen 20. The printing table 10 receives the substrate 21 from the carry-in conveyor 25 and moves the substrate 21 in the horizontal direction (XYθ direction) to align it with the screen 20, and brings the substrate 21 close to the screen 20 surface. Or a table raising / lowering mechanism 12 for contacting.

  A substrate receiving conveyor 26 is provided on the upper surface of the printing table 10. The substrate 21 carried by the substrate carrying conveyor 25 is received on the printing table 10, and when printing is completed, the substrate 21 is discharged to the substrate carrying conveyor 27.

  The screen printing apparatus has a function of automatically aligning the screen 20 and the substrate 21. That is, the CCD camera 15 images the alignment marks provided on each of the screen 20 and the substrate 21 and performs image processing to obtain a positional shift amount, and the XYθ table 11 is corrected so as to correct the shift amount. It is driven and aligned.

  Note that the printing control unit 36 including the plate separation control unit 39, the drive control unit of each unit, and the printing press control unit 30 provided with the image input unit 37 that processes the image signal from the CCD camera 15 are included in the main frame of the printing press. A data input unit 50 provided inside for rewriting control data, changing printing conditions, and the like, and a display unit 40 for monitoring the printing status and captured recognition marks are provided outside the printing press. It is arranged.

  The printing press control unit 30 has a printing control unit 36 for controlling the filling unit 60, and it is easy to select an appropriate filling / printing mode depending on the pitch of the bump to be produced, the difference in the solder ball particle diameter, and the type of the metal mask to be used. Select setting is possible.

  In addition, a correlation value calculation unit 31 that calculates a correlation value according to an input image, a shape estimation unit 32 that calculates a shape based on the captured image and data from the dictionary 38, a position coordinate calculation unit 33 that calculates a position coordinate, dimensions A calculation unit 34 is provided, and based on position recognition marks provided on the substrate 21 and the screen 20 from data captured by the CCD camera 15, a positional deviation amount is obtained, and an XYθ table is determined based on a command from the XYθ table control unit. 11 is driven to perform alignment.

  Next, the operation of the printing apparatus will be described taking the solder ball filling / printing unit as an example. The substrate 21 on which the solder bumps are formed is supplied to the substrate receiving conveyor 26 by the substrate carry-in conveyor 25. When the substrate 21 is transported to the position of the printing table 10, the substrate 21 is transferred from the substrate receiving conveyor 26 onto the printing table 10 by raising the printing table 10. The substrate 21 delivered to the printing table 10 is fixed at a predetermined position on the printing table 10. After fixing the substrate 21, the CCD camera 15 is moved to a substrate mark position registered and set in advance. The situation is shown in FIG.

  Subsequently, the CCD camera 15 images a position recognition mark (not shown) provided on the substrate 21 and the screen 20 and transfers it to the printing press control unit 30. The image input unit 37 in the printing press control unit obtains the amount of positional deviation between the screen 20 and the substrate 21 from the image data, and the printing press control unit 30 operates the XYθ table control unit 35 that moves the printing table 10 based on the result. Thus, the position of the substrate 21 relative to the screen 20 is corrected and aligned.

  The situation after the alignment operation is completed is shown in FIG. First, a predetermined amount of retraction is performed until the CCD camera 15 does not interfere with the print table 10. After the CCD camera 15 is retracted, the printing table 10 is raised and the substrate 21 and the mask 20 are brought into contact with each other. In this state, the print head elevating mechanism 4 is operated to bring the squeegee (in the figure, the squeegee 3 is shown, but in the solder ball filling step, it becomes the slit-like body 63 at the tip of the filling unit 60) into contact with the screen surface. Next, an opening provided on the screen surface from the opening of the slit-like body 63 is moved horizontally by rotating and driving the motor 2g for driving the print head while vibrating and swinging the slit-like body 63. The solder balls 24 are filled in the electrode pads 22 of the substrate 21 via

  The print head 2 moves up after a certain distance stroke in the horizontal direction. Then, the printing table 10 is lowered, the screen 20 and the substrate 21 are separated, and the solder balls 24 filled in the openings of the screen 20 are transferred to the substrate 21. And the board | substrate 21 with which the solder ball 24 was printed is sent to the following process through the board | substrate carrying-out conveyor 27. FIG.

  As described above, the substrate 21 and the screen 20 are provided with two or more recognition alignment marks at the same relatively position. Each of these marks is recognized by the special CCD camera 15 having two vertical fields of view, the mark on the screen 20 is recognized from below, the mark on the substrate 21 is recognized from above, and all the marks provided at predetermined positions are all recognized. The position coordinates are read, the amount of displacement of the substrate 21 with respect to the screen 20 is calculated and corrected, and the substrate 21 is aligned with the screen 20.

  FIG. 6 shows the opening state of the screen after printing the flux. FIG. 6A shows the state of the entire screen, the state of the opening in which one electrode group is provided in FIG. 6B, and the state of the opening after printing the flux 23 in FIG. FIG. 6C shows the opening state of the normal screen 20 after the flux 23 is printed. The flux 23 is sufficiently filled in the opening 20k of the screen 20 by setting the appropriate screen gap (the distance between the screen and the substrate), the printing pressure (the pressing force of the squeegee to the screen) and the squeegee speed, and simultaneously with the passage of the squeegee 3. Since the substrate 21 and the screen 20 are separated from each other, the flux 23 can be reliably transferred to the electrode pad 22 portion of the substrate 21. The screen 20 is fixed to the plate frame 20c.

  The viscosity of the screen printing flux 23, thixotropy, and the fineness of the diameter of the opening 20k of the screen 20 are affected, and the situation of the 20k portion of the screen 20 after printing is completely within the opening under normal printing conditions. However, the flux 23 is not lost, but a thin film can be formed.

  If the opening 20k of the screen 20 becomes clogged due to factors such as bleeding, scattering, and drying of the flux 23, or if the plate separation or transferability is deteriorated, the printing result becomes uneven. The print status can be determined by checking the printing screen 20 without checking the substrate 21. (1) of FIG. 6c shows a state in which the screen opening is normal, (2) shows a partially clogged state, and (3) shows a totally clogged state. In the portion where the transfer amount to the substrate side is large, the residual amount of flux to the opening side of the screen is small, and on the contrary, in the portion where the transfer amount to the substrate side is small, the residual amount of flux to the opening side of the screen is large. . That is, the state where the printing state on the substrate 21 is reversed can be observed on the screen 20 side.

  Whether the screen 20 is open or not is determined as follows. The opening state of the screen 20 is imaged by the CCD camera 15, and the captured image is taken into the printing press control unit 30 via the image input unit 37. Subsequently, the image of the reference model of the opening state of the screen 20 stored in advance in the dictionary 38 is compared with the image of the opening state of the screen 20 captured in the above, and the dimension calculation unit 34 determines whether the “normal” or “bad” ( NG) ". As a result of the determination, “normal” indicates that the screen opening is in a normal state, and “bad” (NG) indicates a state in which the screen opening is partially clogged or clogged. .

  The opening state of the screen 20 determined to be defective (NG) after printing the flux is shown in (2) and (3) of FIG. In (2), the printing appears completely uneven and the pattern appears mottled. This detection can be easily made by pattern matching using a black and white camera.

  On the other hand, in the case of NG as shown in (3), the flux 23 is not printed on the substrate 21 but remains in the opening 20k portion of the screen 20 in a large amount. For this reason, since the degree of the remaining flux can be determined based on the difference in color density, it can be easily determined by comparison using a gray scale model based on image processing. Alternatively, it may be determined by color difference comparison using a color camera.

  In order to confirm the state of the opening of the screen 20 with the positioning CCD camera 15, a stable image is obtained by illuminating upward from the lower part of the screen 20 and confirming with the CCD camera disposed above the screen 20. Can be taken. A method of applying illumination from the upper side to the lower side of the screen 20 may be taken. Since the CCD camera 15 has upper and lower cameras (imaging units), when it is used as a positioning camera for imaging a positioning mark, upward and downward cameras are used, and the state of the opening of the screen 20 after printing is determined. When used as an inspection camera for observation, the upper camera is used.

  After the state of the screen 20 is inspected, if the NG signal such as clogging of the screen opening or flux contamination is issued from the dimension calculation unit 34, the inspection result is provided in the printing apparatus by a command from the printing press control unit 30. Cleaning is automatically carried out by the underlay cleaning device 45 (see FIG. 5), and the flux 23 is supplied and replenished as necessary. In addition, the substrate which has become NG is made to stand by on a conveyor in a subsequent process according to an instruction from the printing press controller 30 together with an NG signal so as not to perform the processes after the solder ball printing, and is discharged out of the line. The magazine may be discharged in a batch by using an inline NG substrate stocker or the like. The NG substrate can be used again for flux printing after being washed in an off-line process.

  FIG. 7 shows the structure of the solder ball printing head (filling unit 60). The filling unit 60 includes a ball case that stores the solder ball 24 in a space formed by the housing 61, the lid 64, and the shib-like body 62, and a slit-like body 63 that is provided at a distance from the shib-like body 62. It is composed of The shib-like body 62 is formed of an extremely thin metal plate having a mesh-like opening or a continuous rectangular slit or the like so as to match the diameter of the solder ball 24 to be supplied. A slit-like body 63 is disposed below the shib-like body 62, and the slit-like body 63 is configured to be in surface contact with the screen 20.

  The degree of contact and gap of the slit-like body 63 with respect to the screen 20 can be finely adjusted by the print head lifting mechanism 4 not shown in the figure. The slit-like body 63 uses a magnetic material, and is an ultra-thin metal having an opening such as a mesh-like opening or a continuous rectangular slit so as to match the diameter of the target solder ball 24 and the opening size of the screen 20. It is made of a plate.

  FIG. 8 shows a horizontal vibration mechanism that vibrates a shib-like body 62 provided in a ball case as a solder ball storage portion in the horizontal direction. A support member 70 having a vibration means 65 attached at a position parallel to the side surface of the ball case is provided on the top of the lid 64. With this configuration, the shib-like body 62 is vibrated by being vibrated by the vibration means 65 from the side surface side of the ball case. By vibrating the shib-like body 62, the slit-like opening provided in the shib-like body 62 can be opened larger than the diameter of the solder ball 24.

  As a result, the solder ball 24 housed in the ball case falls onto the slit-like body 63 from the slit portion of the shib-like body 62. The amount of the solder ball 24 dropped on the slit-like body 63, that is, the supply amount of the solder ball 24 can be adjusted by varying the vibration energy by the vibration means 65.

  The vibration means 65 shown in the figure uses an air rotary vibrator, and can control the frequency by finely adjusting the compressed air pressure by digital control. The frequency may be varied by changing the compressed air flow rate. Further, the shib-like body 62 and the ball case vibrate the solder balls 24 accommodated in the ball case by the vibration means 65 to cancel and disperse the suction force due to the Van Desworth force acting between the solder balls 24. The dispersion effect enables adjustment in consideration of production efficiency so that the supply amount of the solder balls does not change due to the influence of temperature and humidity in the material of the solder balls 24 and the production environment.

  FIG. 9 shows a horizontal swing mechanism of the filling unit 60. The slit-like body 63 is formed using a magnetic material. By using the magnetic material, the slit-like body 63 can be attracted to the screen 20 formed of the magnetic material by the magnetic force from the magnet built-in stage (printing table 10). As shown in FIG. 9, the horizontal swing mechanism is configured as follows. A linear guide 67 is provided above the support member 70, and a filling unit support member 71 provided with a linear rail so that the linear guide 67 can move is provided. The filling unit support member 71 is provided with a drive motor 68. An eccentric cam 66 provided on the drive motor shaft is attached, and the eccentric cam 66 rotates to move the support member in the left-right direction. It has a configuration.

  That is, the horizontal swing mechanism in the horizontal direction rotates the eccentric cam by the driving motor 68 to give the slit-like body 63 a swing operation with an arbitrary stroke amount. Since the slit-like body 63 swings while being attracted to the screen 20 by the magnetic force, the solder ball 24 can be reliably rolled without a gap between the slit-like body 63 and the screen 20. In addition, an efficient filling operation can be performed while the solder ball 24 is surely supplemented to the opening of the slit-like body 63 depending on the opening size of the slit-like body 63. The cycle speed of the screen 20 and the swing operation can be arbitrarily changed by controlling the speed of the driving motor 68, and the filling tact of the solder ball 24 can be set in consideration of the line balance. In addition, the filling rate can be controlled by adjusting the cycle speed in accordance with the material type of the solder balls 24, the opening of the screen 20, and the environmental conditions.

  FIG. 10 is a diagram showing a configuration in which a spatula is provided on the filling head. After the solder ball 24 is supplied onto the substrate 21 by the filling unit 60, when the screen 20 is separated from the surface of the substrate 21, that is, when the solder ball is transferred onto the substrate by separating the plate, the solder ball 24 is formed into the plate surface of the screen 20. If there is a remainder, the solder ball 24 falls onto the substrate 21 through the opening of the screen 20 and causes a defect of the excessive solder ball. Therefore, in this embodiment, the spatula-like body 69 is provided at substantially the same height as the slit-like body 63 with an interval from the ball case in the traveling direction of the filling unit 60. The tip of the spatula 69 is polished to a very thin and highly flat state so that the solder ball 20 does not protrude from the filling unit 60 in close contact with the screen 20.

  Further, the spatula-like body 69 is made of a magnetic material and is attracted to the screen 20 by a magnetic force like the slit-like body 63, so that the solder ball 24 can be prevented from coming out of the filling unit 60. Note that the spatula-like body 69 may be provided in the entire outer peripheral portion of the ball case.

  In FIG. 11, the figure of the structure which provides an air curtain in a filling unit part is shown. With the spatula 69, there can be almost no ball remaining on the plate surface of the screen 20. However, the influence of the remaining ball due to the minute displacement of the plate surface of the screen 20 can be considered. Therefore, in this embodiment, an air curtain is installed in order to eliminate defects caused by excessive solder balls. That is, an air jet 75 is provided on a motor support member that supports a head lifting mechanism (vertical movement motor) 4 constituting the print head 2 so that an air curtain is formed around the filling unit. The jet outlet 75 is configured to be supplied with compressed air from a compressed air supply source (not shown).

  By this air curtain, when the filling unit moves in the direction of the substrate end face, the protruding ball is pushed and rolled by the compressed air toward the filling unit operation direction side, so that there is no remaining ball on the plate surface.

  FIG. 12 is a diagram for explaining a screen filling state inspection after solder ball printing. 12 (a) and 12 (b) are the same as FIG. 6 and will not be described here.

  The solder ball filling state of the screen 20 after the solder ball filling / printing is shown in (1) to (3) of FIG. The state in which the solder balls 24 are completely filled in the openings of the screen 20 can be observed as shown in (1). (2) shows a state where solder ball filling is incomplete. (3) shows a double ball state in which a plurality of solder balls 24 are adsorbed at the time of filling, and a state in which excessive solder balls remain on the plate surface of the screen.

  Even if the plate is released in the states (2) and (3) and the substrate is passed to the subsequent process, a rejected product is produced. Therefore, before performing the plate separation operation, it is possible to correct the rejected product to a non-defective product by checking the filling state on the plate surface of the screen 20 and retrying the filling / printing operation by the filling unit 60. is there. This detection can be made by pattern matching compared with a non-defective model. After the solder ball filling and printing, the line sensor camera attached to the print head side performs batch recognition in units of areas. If it is NG, the solder ball filling / printing is executed again. If it is acceptable, the plate separation operation is executed and the substrate 21 is discharged to the subsequent process.

  FIG. 13 is a diagram for explaining the repair work in the inspection / repair unit after filling the solder balls. FIG. 14 is a diagram for explaining a filling failure situation after filling the solder balls. As shown in FIG. 14, the solder ball filling failure includes failure modes such as no balls, double balls, misaligned balls, and excessive balls.

  In the inspection / repair unit, first, after the solder ball filling / printing is completed, the filling state on the substrate is confirmed by a CCD camera. When a defect is detected, the position coordinates of the defective part are obtained. In the case of defects such as double balls, misaligned balls, crushing, or excessive balls, the vacuum suction nozzle 86 for suction is moved to the position of the solder ball, vacuum suction is performed, the defective ball is thrown away, and the vacuum ball breaks. A disposal box is provided to drop and discard the ball.

  When an electrode pad portion that is not supplied due to insufficient supply of the solder ball 24 is detected, the normal solder ball 24 stored in the solder ball storage portion 84 is adsorbed by the dispenser 87 and is supplied to the flux supply portion 85. The dispenser 87 that adsorbs the solder balls 24 to the accumulated flux 23 is moved, and the solder balls 24 are immersed in the flux 23, whereby the flux 23 is added to the solder balls 24. The repair operation is completed by moving the dispenser 87 that has adsorbed the solder balls 24 added with the flux 23 to the defective portion of the substrate and supplying the solder balls to the defective portion.

  In the previous inspection, when the defective ball is removed with a crushed ball, a misaligned ball, or the like, the defect can be repaired by the repair work described above.

  FIG. 15 illustrates a schematic configuration of the inspection / repair apparatus. In this figure, the inspection / repair unit is shown as one independent device.

  The inspection target substrate 82 is conveyed on the carry-in conveyor 88 on the inspection unit conveyor 90 in the direction of the white arrow. A gate-type frame 80 is provided on the inspection unit conveyor 90, and a line sensor 81 is provided on the loading-side conveyor 88 side of the gate-type frame 80 in a direction perpendicular to the substrate transport direction (the direction of the white arrow). is there. The line sensor 81 detects the state of the solder ball 24 printed on the electrode pad 22 on the substrate 21.

  Further, on one foot side that supports the portal frame 80, a solder ball storage portion 84 that stores normal solder balls and a flux supply portion 85 are provided. A disposal box is provided on the other foot side. The gate-shaped frame portion is provided with a vacuum suction nozzle 86 for sucking and removing defective solder balls and a dispenser 87 for repairing defects on the substrate, which can be moved left and right by a linear motor. Thus, the vacuum suction nozzle 86 and the dispenser 87 can be moved in the hatched arrow direction.

  The inspection section conveyor 90 is configured to reciprocate in the direction of the white arrow. According to the defect position of a board | substrate, it is comprised so that a defect position can be match | combined with a dispenser or a vacuum suction nozzle position. The substrate that has been inspected / repaired is carried out by the carry-out conveyor 89 and sent to the reflow apparatus. With the above-described configuration, inspection repair can be performed by the operation described with reference to FIG.

  As described above, it is possible to realize a printing apparatus that can accurately supply solder balls to the electrode pad portion of the substrate and can prevent generation of defective products as much as possible.

It is a figure which shows the outline | summary of a flux printing and a solder ball filling and printing process. It is a figure which shows an example of the bump formation apparatus by solder ball printing. It is a flowchart of bump formation in this Embodiment. It is a figure which shows schematic structure of a screen printing apparatus. It is operation | movement explanatory drawing of a screen printing apparatus. It is a figure which shows the opening state of the screen after flux printing. It is a figure which shows the structure of a solder ball printing head. It is a figure which shows the horizontal vibration mechanism to a solder ball | bowl storage part shib-like body. It is a figure which shows the horizontal rocking | fluctuation mechanism of a solder ball printing head. It is a figure explaining the spatula for solder ball printing heads. It is a figure explaining the air curtain for solder ball printing heads. It is a figure explaining the example of the state of the screen after solder ball printing. It is a figure explaining repair of a solder ball. It is a figure explaining the state of solder ball printing failure. It is a figure explaining the outline | summary of a test | inspection and repair apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printing machine, 2 ... Print head, 3 ... Squeegee, 10 ... Printing table, 11 ... XY (theta) table, 15 ... Camera, 20 ... Screen, 21 ... Board | substrate, 30 ... Printing machine control part, 34 ... Dimension calculation part, 45 ... Cleaning device, 60 ... Filling unit, 63 ... Slit-like body, 65 ... Excitation means, 69 ... Spatula-like body.

Claims (6)

A flux printing unit that prints flux on the electrode pads of the substrate, a solder ball filling / printing unit that supplies solder balls onto the flux-printed electrode, and a state of the substrate on which the solder balls are printed, In the solder ball printing device consisting of the inspection / repair unit that repairs depending on the defective state,
The flux printing unit picks up an image of a positioning mark in order to align a screen having openings corresponding to a plurality of electrode pad positions, a table on which the substrate is placed and fixed, and the substrate and the screen. Positioning camera, inspection camera for observing the state of the screen opening after printing, cleaning means for cleaning and removing screen opening clogging or flux adhesion dirt on the back of the screen, and images captured by the inspection camera And a determination unit that determines a printing defect by comparing the image of the reference model recorded in advance, and determines whether to send the substrate to the process next or exclude it from the line based on the determination result of the determination unit. A solder ball printing apparatus provided with a printing defect generating means for generating a screen cleaning instruction when it is eliminated. A flux printing unit that prints flux on the electrode pads of the substrate, a solder ball filling / printing unit that supplies solder balls onto the flux-printed electrode, and a state of the substrate on which the solder balls are printed, In the solder ball printing device consisting of the inspection / repair unit that repairs depending on the defective state,
A filling unit is provided in the print head provided in the solder ball filling / printing section,
The filling unit is provided with a ball case including a housing, a lid, and a shib-like body, and a slit-like body is provided at a lower portion of the ball case with a gap between the shib-like bodies, and the shib is disposed on the lid via a support member Solder ball printing apparatus characterized by comprising a vibration means for supplying a solder ball to the slit-like body by changing the size of the opening provided in the shib-like body by exciting the like body . The solder ball printing apparatus according to claim 2,
A solder ball printing apparatus comprising a spatula made of a magnetic material around a ball case of the filling unit.   4. A solder ball printing apparatus according to claim 3, wherein said filling unit is provided with a jet of compressed air for forming an air curtain around said ball case.   2. The solder ball printing apparatus according to claim 1, wherein the solder ball filling / printing unit is supplied with the solder ball to the electrode pad on the substrate and then the screen is released before the screen is released. 3. A solder ball printing apparatus comprising solder ball filling state confirmation means for inspecting and confirming a filling / printing state.   5. The solder ball printing apparatus according to claim 4, wherein the inspection / repair unit inspects and confirms a solder ball filling state, and a repair unit that refills a solder ball on an electrode pad without solder ball filling; Solder ball printing characterized by providing a removing means for adsorbing and removing solder balls existing outside the electrode pad and two or more solder balls existing on the electrode pad or solder balls having a ball diameter larger or smaller than a predetermined size apparatus.

Images