Solder ball printing device

[0037] Hereinafter, preferred embodiments of the printing apparatus and bump forming method of the present invention will be described with reference to the drawings. figure 1 Shows the outline of the printing process in the flux printing section and the solder ball filling/printing section. figure 1 (a) shows the flux printing process, (b) shows the state of solder ball filling/printing.

[0038] in figure 1 In (a), the flux is placed on the flux printing screen 20 with openings provided in accordance with the position and shape of the electrode pads 22 provided on the substrate 21 in advance, and the squeegee 3 is moved. A predetermined amount of flux 23 is printed on the electrode pad 22 of the substrate 21.

[0039] In this embodiment, the screen 20 is a screen for flux printing, and a metal screen made by an additive method is used to ensure high-precision pattern position accuracy. As the scraper 3, any one of a square scraper, a sword scraper, or a flat scraper is used. The screen gap, printing pressure, and squeegee speed corresponding to the viscosity/thixotropy of the flux 23 are set, and the printing operation is performed. If the printing volume of the flux 23 is too small, the solder balls cannot be attached to the electrode pads 22 when the solder balls 24 are filled. In addition, during the reflow in the subsequent process after solder ball printing, it will become the main cause of poor pad infiltration, and the perfect shape of the solder bump cannot be formed, which also becomes the main cause of poor solder bump height and insufficient solder connection strength.

[0040]In addition, if the amount of the flux 23 is too large, the flux 23 may adhere to the opening provided on the screen 20b to be described later on the electrode pad 22 during the filling and printing of the solder ball.部20d and other places. If the flux 23 adheres to the opening of the screen, the solder ball 24 adheres to the opening 20d of the screen and cannot be transferred to the electrode pad 22. In this way, flux printing is the process that has the most important factor in terms of the quality of solder ball filling.

[0041] Next, like figure 1 As shown in (b), using a filling unit 60 (printing unit) (refer to Figure 7 The main part of the solder ball filling/printing part of) is to fill/print the solder balls 24 on the electrode pads 22 of the substrate 21 on which the flux 23 is printed. In order to provide one solder ball 24 to each electrode pad 22, the screen 20b has an opening 20d, and the opening 20d is provided in a state in which the opening 20d is aligned with the electrode pad 22. In this way, the metal wire mesh produced by the additive method is used to ensure high-precision pattern position accuracy.

[0042] In order to prevent the solder balls 24 from infiltrating between the substrate 21 and the screen 20b, a neodymium magnet is used in the printing table 10 (magnet stage) that carries the substrate 21. The solder balls are filled with the screen The material of 20b uses nickel as a magnetic material to be attracted by the magnetic force from the printing table 10, so that the gap between the substrate 21 and the screen 20b is substantially zero.

[0043] In addition, on the back side of the screen 20b (the side in contact with the substrate 21), a plurality of tiny pillars (columnar structure) 20a made of nickel are integrally provided with the screen 20b to complete the printing of the flux 23 When the substrate 21 is in close contact, the oozing flux 23 does not adhere to the periphery of the screen opening 20d. Thereby, the escape part of the oozing flux 23 is comprised. In addition, even if the escape portion is formed, due to the magnetic attraction of the printing table 10, the gap between the substrate 21 and the back surface of the screen 20b is very small compared to the diameter of the solder ball, and no solder ball enters. Close.

[0044] In addition, in order to provide the solder balls 24 to the electrode pads 22 at predetermined positions with high accuracy, positioning marks (not shown) are provided on the four corners of the substrate 21. Corresponding to the positioning marks provided on the side of the substrate 21, positioning marks are also provided on the side of the screen 20b. Using CCD camera 15 (reference Figure 4 ) To visually recognize these positioning marks, and perform high-precision alignment such that the positions of the positioning marks provided on the screen 20b side coincide with the positions of the positioning marks on the substrate 21 side. In this embodiment, the alignment is performed by moving the printing table 10 mounted on the substrate 21 in the horizontal direction.

[0045] After the alignment, the gap between the substrate 21 and the screen 20b is reduced, the screen 20b is brought into contact with the substrate 21, the filling unit (printing device) 60 is operated, and the solder balls 24 are filled in the opening 20d of the screen 20b, and This provides the electrode pad 22 on the surface of the substrate 21 on which the flux 23 is printed. Filling unit 60 (refer to Figure 7 On the lower side of ), a slit-shaped body 63 is provided. Through the shaking/forward movement of the filling unit 60, the solder ball 24 is pushed and rotation/vibration is applied to fill the opening 20d of the screen.

[0046] figure 2 A process explanatory diagram of an embodiment of the solder ball printing device is shown in. The device shown in the figure is a device in which the flux printing unit 101, the flux inspection/repair unit 102, the solder ball filling/printing unit 103, and the ball mounting inspection/repair unit 104 are integrally formed. However, each of the above-mentioned parts may be configured as an independent device. In addition, the solder ball mounting inspection/repair section can also have flux inspection/repair functions. In this device, first, the flux 23 is printed on each electrode pad 22 on the substrate 21 by the flux printing unit (screen printing method) 101. After that, use the solder ball filling/printing unit 103 to the electrode pad via the screen 20b through a conveying conveyor (an out conveyor when viewed from the side of the flux printing unit, and a board loading conveyor when viewed from the side of the solder ball filling/printing unit). A solder ball 24 is provided on 22.

[0047] In addition, the significantly different part of the flux printing part 101 and the solder ball filling/printing part 103 is in the printing head. The flux printing part 101 has a squeegee structure, and the solder ball filling/printing part 103 is used to provide solder balls. The filling unit 60 is constituted. The printing heads of the inspection/repair parts 102 and 104 are of a dispenser type suction/providing head structure. In addition, since there is no need to use a screen in the inspection/repair section, there is no need to install a frame support for screen installation.

[0048] image 3 Shows a flowchart of bump formation in this embodiment. After the board is loaded (STEP1), a predetermined amount of flux is printed on the electrode pad 22 (STEP2). Then, check the surface condition of the electrode pad after the flux is printed (STEP3). If the inspection is NG (defective), the NG part is supplied with flux again for repair, and the NG information is fed back to the flux printing part 101, and the under-plate cleaning device 45 automatically performs screen cleaning (STEP4).

[0049] The NG substrate can be placed on the conveyor of the subsequent process together with the NG signal without performing the subsequent process of ball printing and discharged out of the production line. It is also possible to use an online NG substrate storage warehouse, etc., to discharge the structure in batches of inventory. After the NG substrate is cleaned in a process outside the production line, it can be used again for flux printing.

[0050] Next, solder ball filling/printing (STEP5). After solder ball filling/printing, check the solder ball filling state from above the screen to the opening of the screen (STEP6) before stripping. If the inspection result shows that there is insufficient filling, perform the solder ball filling/printing operation (STEP7) again before stripping. As a result, the filling rate of solder balls can be increased.

[0051] If it is OK (pass) in STEP6, it will be removed (STEP8). Then, the inspection/repair device 104 after the solder ball filling is used to check the filling condition (STEP 9). When the filling condition is checked as NG, after the flux is supplied, solder balls are again supplied to the electrode pads of the NG points (STEP10). When the filling condition check is OK, the solder balls are melted again using a reflow device (not shown) to complete the solder bumps.

[0052] Figure 4 The schematic structure of the screen printing device (mainly the flux printing section) in the present invention is shown. Figure 4 (a) is the structure seen from the front of the screen printing device, (b) is a system configuration diagram. In addition, Figure 5 (a) and (b) show diagrams for explaining the operation of the screen printing device.

[0053] The main frame 1 is provided with a not-shown plate frame supporter, and the plate frame supporter is equipped with a mask. The mask is placed on the plate frame 20c (refer to Figure 6 ) Is pasted with a screen 20 having a printed pattern as an opening. In the figure, above the screen 20, a print head 2 provided with a squeegee 3 is arranged.

[0054] In the case of the flux printing unit 101, a squeegee 3 made of urethane is attached to the printing head 2. In the case of the solder ball filling/printing section 103, instead of the squeegee 3, a filling unit (printing device) 60 composed of a slit-shaped body 63 or the like is installed in the printing head 2. The print head 2 is configured to be movable in the horizontal direction by the print head moving mechanism 6 and in the vertical direction 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.

[0055] Below the screen 20, a printing table 10 for carrying and holding a substrate 21 as an object to be printed is provided so as to face the screen 20. The printing table 10 has: an XYθ table 11 that moves the substrate 21 in the horizontal direction (XYθ direction) to perform alignment with the screen 20; a table lift mechanism 12 that is used to receive the substrate 21 from the carry-in conveyor 25, And make the substrate 21 approach or touch the surface of the screen 20.

[0056] A substrate receiving conveyor 26 is provided on the upper surface of the printing table 10 to receive the substrate 21 carried in by the substrate carrying-in conveyor 25 onto the printing table 10 and eject the substrate 21 onto the substrate carrying-out conveyor 27 when printing is finished.

[0057] The screen printing device has a function of automatically aligning the screen 20 and the substrate 21. That is, the CCD camera 15 captures the alignment marks respectively provided on the screen 20 and the substrate 21, performs image processing to obtain the positional deviation, and drives the XYθ stage 11 to correct the deviation to perform alignment.

[0058] In addition, the printing control section 30 including the printing control section 36 composed of the stripping control section 39 and the drive control section of each part, and the image input section 37 that processes the image signal from the CCD camera 15 is installed in the printing press. Inside the main body frame, a data input unit 50 for rewriting control data, changing printing conditions, etc., and a display unit 40 for monitoring printing conditions and the imported identification marks are arranged outside the printer .

[0059] The printing control section 36 that controls the filling unit 60 in the printing press control section 30 can be easily selected and set according to the spacing of the bumps to be produced, the diameter of the solder balls, and the type of metal mask to be used. Filling/printing mode.

[0060] In addition, it also has a correlation value calculation unit 31 that calculates a correlation value from an input image, a shape estimation unit 32 that calculates a shape based on the captured image or data from the dictionary 38, a position coordinate calculation unit 33 that calculates position coordinates, and The size calculation unit 34 obtains the amount of positional deviation based on the position recognition marks provided on the substrate 21 and the screen 20 based on the data captured by the CCD camera 15, and drives the XYθ stage 11 based on the instruction of the XYθ stage control unit to perform alignment quasi.

[0061] Next, taking the solder ball filling/printing section as an example, the operation of the printing device will be described. The substrate 21 on which the solder bumps are formed is supplied to the substrate receiving conveyor 26 through the substrate carrying-in conveyor 25. After the substrate 21 is transported to the position of the printing table 10, the printing table 10 is raised, and the substrate 21 is transported from the substrate receiving conveyor 26 to the printing table 10 accordingly. The substrate 21 conveyed to the printing table 10 is fixed to a predetermined position of the printing table 10. After the substrate 21 is fixed, the CCD camera 15 is moved to a substrate mark position registered in advance. Figure 5 (a) indicates this situation.

[0062] Then, the CCD camera 15 takes an image of a mark (not shown) for position recognition provided on the substrate 21 and the screen 20 and transmits it to the printer control unit 30. The image input unit 37 in the printer control unit is used to obtain the positional deviation between the screen 20 and the substrate 21 based on the image data. Based on the result, the printer control unit 30 operates the XYθ stage control unit 35 of the moving printing table 10 to control the substrate 21 is corrected/aligned with respect to the position of the screen 20.

[0063] Figure 5 (b) shows the situation after the positioning operation is completed. First, the CCD camera 15 operates and retracts to a position where it does not collide with the printing table 10 by a predetermined amount. After the CCD camera 15 completes the retreat, the printing table 10 is raised to bring the substrate 21 into contact with the screen 20. In this state, the print head lifting mechanism 4 is operated so that the squeegee (the squeegee 3 is shown in the figure, but the slit-shaped body 63 at the tip of the filling unit 60 in the solder ball filling step) contacts the screen surface. Then, while vibrating/shaking the slit-shaped body 63, the print head driving motor 2g is rotated and driven, so that the slit-shaped body 63 moves horizontally on the screen surface and passes through the opening of the slit-shaped body 63. The opening on the screen surface is filled with solder balls 24 in the electrode pads 22 of the substrate 21.

[0064] The print head 2 swings a fixed distance in the horizontal direction and then rises. Then, the printing table 10 is lowered, the screen 20 is separated from the substrate 21, and the solder balls 24 filled in the opening of the screen 20 are transferred to the substrate 21. The substrate 21 on which the solder balls 24 are printed is sent to the next process via the substrate conveyer 27.

[0065] In addition, as described above, two or more identification position alignment marks are provided on the substrate 21 and the screen 20 at the same position facing each other. For each of the two marks, a special CCD camera 15 with two vertical fields of view is used to recognize the mark on the screen 20 from below and the mark on the substrate 21 from above to read out all the marks placed on the specified position. The position coordinates perform position calculation/correction on the deviation amount of the substrate 21 with respect to the screen 20, so that the substrate 21 is aligned with the screen 20.

[0066] Figure 6 Indicates the opening state of the screen after printing flux. Figure 6 (a) Represents the overall condition of the screen, Figure 6 (b) shows the state where the opening of one electrode group is provided, Figure 6 (c) shows the state of the opening after the flux 23 is printed. Figure 6 (c) shows the opening state of the normal screen 20 after the flux 23 is printed. By setting an appropriate screen gap (the interval between the screen and the substrate), the printing pressure (the pressing force of the squeegee against the screen) and the squeegee speed, the opening 20k of the screen 20 is fully filled with flux 23, and the squeegee 3 The substrate 21 and the screen 20 are released at the same time as the passage, whereby the flux 23 can be reliably transferred to the electrode pads 22 of the substrate 21. In addition, the screen 20 is fixed in the plate frame 20c.

[0067] Affected by the viscosity and thixotropy of the flux 23 for screen printing, and the refinement of the diameter of the opening 20k of the screen 20, the condition of the opening 20k of the screen 20 after printing is likely to produce a thin film. It is not a situation where the flux 23 completely disappears from the opening in the normal printing state.

[0068] If the opening 20k of the screen 20 is clogged due to the leakage, scattering, and drying of the flux 23, or the release or transferability is poor, the printing result will be uneven. In this printing state, it can be judged whether it is acceptable or not by checking the screen 20 for printing, without checking the substrate 21. Figure 6 (1) of (c) indicates a state where the opening of the screen is normal, (2) indicates a state where clogging occurs partially, and (3) indicates a state where all clogging occurs. In the part where the amount of transfer to the substrate side is large, the amount of flux remaining on the opening side of the screen is small. On the contrary, in the part where the amount of transfer to the substrate side is small, the amount of flux remaining on the opening side of the screen is small. many. That is, the state in which the printing state on the substrate 21 is reversed can be observed from the screen 20 side.

[0069] It is judged whether the opening state of the screen 20 is qualified or not in the following manner. The opening state of the screen 20 is captured by the CCD camera 15, and the captured image is taken into the printer control unit 30 through the image input unit 37. Then, the image of the reference model of the opening state of the screen 20 stored in the dictionary 38 in advance is compared with the image of the opening state of the screen 20 captured as described above, and the size calculation unit 34 determines whether "normal" or " Bad (NG)". The judgment result "normal" means that the screen opening is in a normal state, and "bad (NG)" means that the screen opening is partially clogged or completely clogged.

[0070] Figure 6 (2) and (3) of (c) show the opening state of the screen 20 judged to be defective (NG) after the flux is printed. (2) It seems that the printing is completely uneven and the pattern appears mottled. This detection can also be easily determined by pattern matching using a black-and-white camera.

[0071] On the other hand, in the case of NG as in (3), the flux 23 is not printed on the substrate 21 but a lot of it remains in the opening 20k of the screen 20. Therefore, the degree of flux residue can be judged by the different shades of the colors, so it can be easily judged by comparing the shades of gray level models of image processing. Alternatively, it can also be determined by comparison of chromatic aberration using a color camera.

[0072] In addition, in order to use the CCD camera 15 for positioning to check the status of the opening of the screen 20, lighting is performed from the lower part of the screen 20 upward, and the method of checking with the CCD camera arranged above the screen 20 can achieve stability. Image. It is also possible to adopt a method of lighting from above the screen 20 to the bottom. The CCD camera 15 has cameras (imaging parts) on the top and bottom. Therefore, when used as a positioning camera for photographing positioning marks, upward and downward cameras are used to observe the state of the opening of the screen 20 after printing. When using the inspection camera, the upper camera is used.

[0073] After inspecting the state of the screen 20, if the inspection result is that the screen opening is clogged, the screen is stained and other NG signals are sent from the size calculation unit 34, the command from the printer control unit 30 is installed in the printing device. The under-plate cleaning device 45 (refer to Figure 5 ) Automatically clean, and provide flux 23 as needed. In addition, the NG board no longer performs the subsequent processes after solder ball printing, and along with the NG signal, in accordance with the instructions of the printer control unit 30, stands by on the conveyor of the subsequent process and is discharged out of the production line. It can also be discharged in stock batches by using online NG substrate storage. After the NG substrate is cleaned in a process outside the production line, it can be used again for flux printing.

[0074] Next, right Figure 7 The method of detecting the land surface of the camera using the inner diameter side illumination is described in this section. Regarding the flux 23 transferred to the electrode pad 22, it is difficult to recognize the presence or absence of the flux 23 because the illuminating light easily passes through the flux 23 in the microscope observation of the reflected light method. In the case where the diameter of the transferred flux 23 is larger than the diameter of the electrode pad 22, and in the case where the transfer position deviation occurs and the transfer is out of the electrode pad 22, it can be observed with a microscope using reflected light. The presence or absence of the flux 23 is determined, but since it is difficult to determine the presence or absence of the flux 23 formed on the electrode pad 22, it is impossible to determine whether the transfer area is appropriate.

[0075] Therefore, such as Figure 7 As shown in the bottom figure, if the detection method using the CCD camera 15 using the inner diameter side illumination 15L is used, the transferred flux 23 is illuminated not from above, but in the outer circumferential direction of the flux 23. Using the effect of the emergence of the subject, the determination of the flux 23 can be performed. Regarding the automatic detection, as in the case described above, it can be dealt with by switching the illumination provided in the CCD camera 15 from downward illumination to the inner diameter illumination 15L.

[0076] In addition, by combining a mechanism that moves up and down in the direction perpendicular to the electrode pad 22 and a position measuring mechanism for the CCD camera 15 with inner diameter illumination, it is possible to measure the positional relationship between the vertex and the bottom of the flux 23. The height of the flux 23 and the amount of the flux 23 are measured.

[0077] Even if the wavelength of the illumination used is in the visible light region, if it is set to blue light having a wavelength close to the ultraviolet region, the discriminability is good.

[0078] In addition, by making the flux 23 contain a fluorescent material, and observing the printing result using illumination having a wavelength in the ultraviolet region, the flux 23 can be easily distinguished by the light emitted by the fluorescent material contained in the flux 23.

[0079] Figure 8 Shows the structure of the solder ball printing head (printing unit, filling unit 60). The filling unit 60 is composed of a ball box that accommodates the solder balls 24 in the space formed by the frame 61, the cover 64, and the mesh-shaped body 62, and slit-shaped slits provided at intervals below the mesh-shaped body 62. Body 63 constitutes. The mesh-like body 62 is formed of an extremely thin metal plate having openings such as mesh-like openings or continuous rectangular slits so as to be suitable for the diameter of the solder balls 24 to be supplied. In the lower part of the mesh-like body 62, the slit-like body 63 is arrange|positioned, and it is comprised so that the slit-like body 63 and the wire mesh 20b may contact surface.

[0080] The print head raising and lowering mechanism 4, which is not shown in the figure, can be used to finely adjust the contact degree/gap of the slit-shaped body 63 with respect to the screen 20b. The slit-shaped body 63 uses a magnetic material, and is made of an extremely thin metal having openings such as mesh-like openings or continuous rectangular slits in a manner suitable for the diameter of the target solder ball 24 and the opening size of the screen 20. The board is formed.

[0081] The screen 20b is made of nickel and is integrally formed with a screen with pillars (columnar structure) 20a in the printing pattern part and pillars. A printing table 10 is installed on the substrate placement part, and a surface magnetic flux density of 500 is laid on the printing table 10. ~2000G neodymium sheet magnet. The attractive force generated by the magnetic force of the screen 20b and the printing table 10 is set to 10~100gf/cm 2 Therefore, the surface of the substrate 21 and the screen 20b can be brought close to each other in such a way that there is no gap greater than or equal to the diameter of the solder ball. When the above-mentioned attractive force is too weak, there is a gap between the lower part of the screen 20b and the surface of the substrate 21, which becomes a main cause of defects in which the solder balls 24 enter.

[0082] When the substrate 21 leaves the screen 20b after the printing, by controlling the descending speed and acceleration of the printing table 10, the screen 20b is pulled off in a manner propagating from the periphery of the substrate to the middle part of the substrate, so that uniform stripping can be achieved. . However, if the above-mentioned gravitational force generated by the magnetic force is too strong with respect to the tension of the screen, it cannot be controlled.

[0083] In addition, a printing table 10 on which a neodymium sheet magnet 10s with a surface magnetic flux density of 500-2000G, a slit-shaped body 63 of a printing unit (filling unit) 60 and a screen 20b are laid on the substrate placement part The gravitational force generated by the magnetic force is set to 0.1~10gf/cm 2. The slit-shaped body 63 for printing and the slit-shaped body for ball recovery constituting the printing unit (filling unit) 60 are made of SUS304, and the screen is made of nickel. For the solder balls on the screen, one side of the slit-shaped body 63 is The magnetic force generated by the above-mentioned printing table 10 acts evenly and softly in the direction perpendicular to the screen 20b to hold the tiny ball in the slit-shaped body 63, and to the screen efficiently without causing deformation and damage to the ball. The operation of filling the opening 20d.

[0084] Picture 9 It shows a horizontal vibration mechanism that vibrates the mesh-shaped body 62 provided on the ball box 61 of the solder ball housing portion of the printing unit in the horizontal direction. On the upper part of the cover 64, a support member 70 is provided, and the support member 70 is provided with a vibration unit 65 at a position parallel to the side surface of the ball box. With this structure, the vibrating unit 65 applies vibration from the side surface of the ball box, thereby vibrating the mesh-shaped body 62. By vibrating the mesh-like body 62, the slit-shaped opening provided in the mesh-like body 62 can be opened larger than the diameter of the solder ball 24.

[0085] As a result, the solder balls 24 contained in the ball box go from the slit portion of the mesh-shaped body 62 to the slit-shaped body 63. The amount of solder balls 24 that fall on the slit-shaped body 63, that is, the supply amount of the solder balls 24 can be adjusted by changing the vibration energy of the vibration energizing unit 65.

[0086] The vibrating unit 65 shown in the figure uses a pneumatic rotary vibrator and uses digital control to fine-tune the pressure of the compressed air, so that the number of vibrations can be controlled. You can also change the number of vibrations by changing the compressed air flow. In addition, the mesh-shaped body 62 and the ball box apply vibration to the solder balls 24 contained in the ball box through the vibration unit 65 to cancel the attractive force caused by van der Waals attraction acting between the solder balls 24 and disperse them. The dispersion effect described above can be used to make adjustments focusing on production efficiency, so that the supply amount of solder balls is not affected by the material of the solder balls 24 and the temperature and humidity in the production environment.

[0087]Picture 9 Shows the horizontal shaking mechanism of the filling unit 60. The slit-shaped body 63 is formed using a magnetic material. By using a magnetic material, the magnetic force from the stage (printing table 10) with a built-in magnet can be used to attract the slit-shaped body 63 to the screen 20 formed of the magnetic material. Such as Picture 9 As shown, the structure of the horizontal shaking mechanism is as follows. A linear guide 67 is provided on the upper part of the support member 70, and a filling unit support member 71 having a linear guide rail is provided in such a manner that the linear guide 67 can move. The filling unit support member 71 is provided with a drive motor 68 and an eccentric cam 66 provided on the drive motor shaft is attached. The rotation of the eccentric cam 66 moves the support member in the left-right direction.

[0088] That is, as Picture 10 As shown, in the horizontal direction, the horizontal rocking mechanism uses the driving motor 68 to rotate the eccentric cam 66 to apply a rocking motion to the slit-shaped body 63 by an arbitrary rocking amount. Since the slit-shaped body 63 is oscillated while being magnetically attracted to the screen 20b, the solder ball 24 can be reliably rotated without a gap between the slit-shaped body 63 and the screen 20b. In addition, the opening size of the slit-shaped body 63 can be used to reliably fill the solder balls 24 in the opening 20d of the slit-shaped body 63, and the filling operation can be performed efficiently. The cycle speed of the screen 20 and the shaking motion can be arbitrarily changed by controlling the speed of the driving motor 68, and the filling cycle of the solder balls 24 can be set in consideration of the balance of the production line. In addition, the filling rate can be controlled by adjusting the cycle speed suitable for the material type of the solder balls 24, the opening 20d of the screen 20b, and the environmental conditions.

[0089] Picture 11 A diagram showing a configuration in which a blade-like body (solder ball recovery device) is provided in the filling head. After the solder balls 24 are provided on the substrate 21 by the filling unit 60, when the screen 20b is separated from the substrate 21, that is, when the solder balls are transferred to the substrate 21 and the screen 20b is removed, the screen 20b If the solder balls 24 remain, the solder balls 24 fall onto the substrate 21 through the openings of the screen 20b, which may cause the undesirable phenomenon of excess solder balls. Therefore, in this embodiment, an interval is provided with respect to the ball box in the traveling direction of the filling unit 60, and the blade-shaped body 69 is provided at the substantially same height as the slit-shaped body 63. The tip of the blade-shaped body 69 is polished to be extremely thin and has a high flatness accuracy, and is in a state of being closely attached to the screen 20 b to prevent the solder balls 24 from being exposed to the outside of the filling unit 60. In this way, the squeegee-shaped body 69 can be used to recover the excess solder balls.

[0090] In addition, if a magnetic material is used for the blade-shaped body 69, it is attracted to the screen 20 b by magnetic force like the slit-shaped body 63, so that the solder balls 24 can be prevented from escaping to the outside of the filling unit 60. In addition, the blade-like body 69 may also be provided in the entire area of ​​the peripheral portion of the ball box 61.

[0091] Furthermore, by forming the squeegee-shaped body 69 with a porous foam having pores sufficiently larger than the diameter of the solder ball, printing can be performed while efficiently filling the solder ball 24.

[0092] Picture 12 A diagram showing a structure in which an air curtain is provided in the filling unit 60. Although it is possible to use the blade-like body 69 to basically have no ball remaining on the screen surface of the screen 20b, it is necessary to consider the influence of the ball residue caused by the slight position change of the screen surface of the screen screen 20b. Therefore, in this embodiment, in order to reduce the defects caused by excess solder balls to zero, an air curtain is provided. That is, an air ejection port 75 is provided on a motor support member that supports the head raising and lowering mechanism (up-and-down movement motor) 4 constituting the print head 2 to form an air curtain around the filling unit. The ejection port 75 is supplied with compressed air from a compressed air supply source not shown.

[0093] By providing this air curtain, when the filling unit moves in the direction of the substrate end surface, compressed air is used to push the exposed balls to the side in the operating direction of the filling unit, so that no balls remain on the plate.

[0094] Figure 13 Shows a diagram explaining the inspection of the filling state of the screen after solder ball printing. Figure 13 (a), (b) due to Figure 6 It is the same, so the description is omitted here.

[0095] Figure 13 (1) to (3) of (c) show the solder ball filling state of the screen 20b after solder ball filling/printing. The state where all the solder balls 24 are filled in the opening of the screen 20b can be observed as shown in (1). (2) Represents the state where the solder balls are not completely filled. (3) It shows a double ball state in which the solder balls 24 are attracted to each other during filling, and a state in which excess solder balls remain on the layout of the screen.

[0096] In the state of (2) and (3), the plate is released and the substrate is transferred to the subsequent process to produce unqualified products. Therefore, by checking the filling state on the plate surface of the screen 20b before performing the stripping operation, the filling unit 60 is used to perform the filling/printing operation again, so that the defective product can be restored to a qualified product. In this detection, the pattern matching compared with the qualified product model can be used for judgment. After the solder balls are filled and printed, the linear sensor camera mounted on the print head side is used for collective recognition on a regional basis. If it is NG, perform solder ball filling/printing again. If it passes, the substrate 21 is discharged to the subsequent process after the stripping operation is performed.

[0097] FIG. 14 is a diagram for explaining repair work in the inspection/repair section after solder ball filling. Fig. 15 is a diagram illustrating a state of poor filling after solder ball filling. As shown in Fig. 15, in the solder ball filling failure, in addition to no balls, double balls, positional deviation/bumps, there are other bad modes such as extra balls.

[0098] In the inspection/repair department, first, after the solder ball filling/printing is completed, the CCD camera is used to confirm the filling condition on the substrate. If a defect is detected, the position coordinates of the defective part are obtained. In addition to double balls, position deviation balls, crushing, in the case of excess balls and other bad conditions, a waste box is set to move the vacuum suction nozzle 86 for suction to the position of the solder ball, vacuum suction and move to the defective ball disposal station , The ball is dropped and discarded by vacuum destruction.

[0099] In addition, when an electrode pad portion that has not been supplied due to insufficient supply of solder balls 24 is detected, the normal solder balls 24 accommodated in the solder ball accommodating portion 84 are adsorbed by the dispenser 87, and the solder balls will be adsorbed. The dispenser 87 of the 24 moves to the flux 23 stored in the flux supply part 85, and the flux 23 is added to the solder balls 24 by immersing the solder balls 24 in the flux 23. The dispenser 87 holding the solder balls 24 to which the flux 23 is added is moved to the defective part of the substrate, and the repair work is completed by supplying the solder balls to the defective part.

[0100] In addition, when defective balls such as broken balls and positional deviation balls are eliminated through the previous inspection, the defects can be repaired through the above-mentioned repair work.

[0101] Figure 16 Shows a diagram explaining the schematic structure of the inspection/repair device. In addition, the figure shows that the inspection/repair section is an independent device.

[0102] The inspection target substrate 82 is transported on the carry-in side conveyor 88 and the inspection section conveyor 90 in the direction of the hollow arrow. A door frame 80 is provided on the upper portion of the inspection unit conveyor 90, and a linear sensor 81 is provided in a direction perpendicular to the substrate conveying direction (the direction of the hollow arrow) on the carry-in side conveyor 88 side of the door frame 80. The linear sensor 81 is used to detect the state of the solder balls 24 printed on the electrode pads 22 of the substrate 21.

[0103] In addition, on one leg side supporting the gate-shaped frame 80, a solder ball accommodating portion 84 and a flux supply portion 85 that accommodate normal solder balls are provided. A discard box is provided on the other leg side. A vacuum suction nozzle 86 for sucking and removing defective solder balls and a dispenser 87 for repairing defects on the substrate are provided on the gate-shaped frame portion so that it can be moved left and right by a linear motor. Accordingly, the vacuum suction nozzle 86 and the dispenser 87 can move in the direction of the hatched arrow.

[0104] The inspection part conveyor 90 is configured to be able to reciprocate in the direction of the hollow arrow. The distributor and vacuum suction nozzle can be matched with the defect position according to the defect position of the substrate. In addition, the inspected/repaired substrate is carried out by the carry-out conveyor 89 and sent to the reflow device. With the above structure, inspection and repair can be performed through the operation described in FIG. 14.

[0105] As described above, it is possible to realize a printing device that can accurately supply solder balls to the electrode pad portions of the substrate and prevent the occurrence of defective products as much as possible.