Squeegee of solder ball mounting apparatus and solder ball mounting apparatus

Abstract

An object of the present invention is to obtain a squeegee for a solder ball mounting apparatus and a solder ball mounting apparatus that can prevent breakage of an end coupling portion of the squeegee for a longer period of time and can withstand long-term use.SOLUTION: A squeegee of a solder ball mounting apparatus according to the present invention is a squeegee of a solder ball mounting apparatus for mounting solder balls supplied onto a mask on a surface of a substrate on which a plurality of electrodes are formed, via the mask having openings at positions corresponding to the electrodes, on the electrodes through the openings, the squeegee including a plurality of slits formed in a thin plate shape and having a predetermined angle with respect to an advancing direction at the time of mounting the solder balls, and a connecting portion that connects thin plates separated by the slits at both side end portions in the advancing direction. The connection part is formed so as to be freely expanded and contracted at least in the advancing direction.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a squeegee for a solder ball mounting device and a solder ball mounting device. [Background technology]

[0002] The solder ball mounting device places a mask with openings at positions corresponding to the electrodes on the surface of a substrate on which multiple electrodes are formed and flux is applied, and is equipped with a squeegee with multiple slits in a thin plate, and drops the solder balls into the openings in the mask.

[0003] Patent Documents 1 to 3 disclose techniques for solder ball mounting devices. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-105889 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-135457 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-154193 Summary of the Invention [Problem to be solved by the invention]

[0005] When multiple slits are formed in a thin plate, the squeegee of a solder ball mounting device requires connecting portions on both sides of the squeegee in the direction of travel to connect the strips formed by adjacent slits together so that they do not separate. This squeegee (which may be referred to as a slit squeegee hereinafter because it has slits) is formed in a semi-cylindrical shape, and its cylindrical portion is pressed against and contacts the mask as it moves over the mask. Solder ball mounting devices using squeegees configured in this way have a high solder ball mounting rate and are useful, so they have been widely used in this field for a long time. As a result, there has been a long-term demand for devices that can be used for a longer period of time.

[0006] That is, in conventional squeegees, even when a pressing force is applied to the center, the slits open slightly, absorbing the pressing force. However, there are connecting portions at both ends of the squeegee in the direction of travel that connect the strip-shaped members together. As a result, these connecting portions cannot absorb the pressing force and are subjected to stress, which can cause the connecting portions to break over long periods of use. For this reason, in conventional technologies (the technologies of Patent Documents 1 to 3), the squeegee must be replaced periodically after, for example, several hundred to several thousand consecutive uses.

[0007] An object of the present invention is to provide a squeegee for a solder ball placing device and a solder ball placing device that can withstand long-term use and that can prevent damage to the connecting portions at both ends of the squeegee for a long period of time. [Means for solving the problem]

[0008] The squeegee of the solder ball mounting device of the present invention is a squeegee of the solder ball mounting device that mounts solder balls on the surface of a substrate on which a plurality of electrodes are formed through a mask having openings at positions corresponding to the electrodes, and mounts the solder balls on the electrodes through the openings.The squeegee is formed in the shape of a thin plate and has a plurality of slits that are at a predetermined angle with respect to the direction of movement of the solder balls when mounting them, and has connecting portions at both end portions in the direction of movement that connect the thin plates separated by the slits, and the connecting portions are formed to be flexible and expandable at least in the direction of movement.

[0009] The solder ball mounting device of the present invention is a solder ball mounting device that uses a mask having openings at positions corresponding to the electrodes on a substrate surface on which a plurality of electrodes have been formed and flux has been applied, and uses a squeegee formed in a semi-cylindrical shape with a plurality of slits in a thin plate to mount solder balls onto the electrodes through the openings.The squeegee is formed in the shape of a thin plate, and in the central part corresponding to the substrate surface, it has a plurality of slits at a predetermined angle to the direction of travel, and on both side ends in the direction of travel it has connecting parts that connect the thin plates separated by the slits, and the connecting parts are formed to be flexible and expandable at least in the direction of travel. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a squeegee for a solder ball loading device and a solder ball loading device that can withstand long-term use and that can prevent damage to the connecting portions at both ends of the squeegee for a long period of time. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram illustrating the overall configuration of a solder ball mounting device. [Figure 2] 10 shows a schematic configuration of the filling head and sweeper head while the filling head is moving leftward. [Figure 3] 10 shows a schematic configuration of the filling head and sweeper head while the filling head is moving to the right. [Figure 4] FIG. 10 is a diagram showing a state in which the sweeper head is moving. [Figure 5] A front view of the filling section is shown. [Figure 6] 6 shows a cross-sectional view taken along line AA in FIG. 5. [Figure 7] 1A and 1B show an overall view and an enlarged view of an excerpt of a slit squeegee according to an embodiment of the present invention. [Figure 8] 8 is an explanatory diagram showing the expansion and contraction state of a connecting portion caused by the stress of the slit squeegee shown in FIG. 7. FIG. [Figure 9] 8 is an enlarged perspective view showing a corner portion of the slit squeegee shown in FIG. 7, and a perspective view showing the slit squeegee attached to a squeegee holder. FIG. [Figure 10] FIG. 2 is a perspective view showing a state in which the slit squeegee is attached to a squeegee holder. [Figure 11] 10A and 10B are diagrams illustrating the operation of the filling head and the sweeper head. [Figure 12] 3 is a continuation of the diagram illustrating the operation of the filling head and sweeper head. [Figure 13] FIG. 10 is a plan view of another embodiment of the slit squeegee of the present invention. [Figure 14] FIG. 10 is a plan view of still another embodiment of the slit squeegee of the present invention. [Figure 15] 1A and 1B are a plan view and a partially enlarged plan view showing a conventional slit squeegee; DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments are illustrative for explaining the present invention, and appropriate omissions and simplifications have been made for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural. The position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc., in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings. [Example]

[0013] There are various methods for printing solder balls on electrode parts. In particular, the pitch of the printing target is becoming smaller, at 40 μm to 150 μm, and the solder ball size is also becoming smaller, at φ20 to φ100 μm. Therefore, there is a demand for technology that can print small solder balls reliably and accurately.

[0014] Hereinafter, preferred embodiments of the solder ball printing device (solder ball mounting device) of the present invention will be described with reference to the drawings.

[0015] The overall configuration of the solder ball mounting device for printing solder balls is shown in Figure 1. Figure 1(a) shows the state in which the mask and substrate are aligned, and Figure 1(b) shows the state in which the solder balls are printed on the substrate.

[0016] The solder ball mounting device 1 is provided with a printing table 21 equipped with a drive unit 22 so that it can move up and down. The printing table 21 is configured as an XYθ table so that it can move in the XYθ directions. A magnet 33 is placed on this printing table 21, and the substrate 20 is placed on top of it. Furthermore, a camera 18 (two-view camera) is used to capture images of alignment marks on the surface of the mask 8, which is attached to the solder ball mounting device 1 via a mask frame 9, and the surface of the substrate 20, and a control unit (not shown) processes the images to determine the positional deviation of the marks. Using the determined deviation amount, the control unit controls the driving of the printing table 21, on which the substrate 20 is placed, in the horizontal direction (XYθ directions) so that the mark positions are aligned, thereby performing alignment. A camera moving frame 24 for moving the camera 18 is provided between the printing table 21 and the back side of the mask 8. This camera moving frame 24 is provided so as to be movable in the front-to-rear direction in FIG. 1.

[0017] After alignment is performed using camera 18, alignment camera 18 is retracted, and as shown in Figure 1(b), drive unit 22 is operated to raise printing table 21 on which substrate 20 is placed, and mask 8 provided on the top is brought into contact with the surface of substrate 20. Thereafter, head up / down drive mechanism 5 is driven to lower filling head 2 (sometimes referred to as transfer head) toward the mask surface, and a filling member (hereinafter sometimes referred to as squeegee or slit squeegee) (see Figure 2), consisting of multiple thin strip-shaped members that make up the filling member of filling unit 3, is brought into contact with the mask surface with a predetermined pressing force.

[0018] The filling member is made equal to or larger than the width of the substrate to be printed, and the solder balls can be filled into the mask openings by moving the filling head 2 once horizontally (longitudinal direction of the substrate). In practice, the filling head is moved back and forth once longitudinally of the substrate to reliably fill the mask openings. When moving the filling head horizontally, the driving mechanism 13 (see Figure 5) provided in the filling unit 3 is operated to rotate the filling unit 3. The filling unit 3 is rotated at a relatively slow speed of 1 to 5 revolutions per second. If it is rotated too quickly, the thin strips that make up the slit squeegee 12 may cut the solder balls being filled, causing volume defects, and may also cause unnecessary vibrations in the mask, resulting in double balls.

[0019] Next, the head drive unit (motor 2g) is driven to rotate ball screw 2b, moving filling head 2 horizontally. As shown in Figure 1, while filling head 2 is moving, filling unit 3 rotates at a predetermined rotation speed in the same direction as the moving direction of filling head 2 at the contact point with the mask surface (so as to sweep out solder balls 11) when loading solder balls. This allows the solder balls to fill the mask openings, and also scrapes up the surrounding solder balls 11 so that they do not remain on the mask surface.

[0020] By rotating the filling member in this manner with its rotation axis positioned parallel to the mask surface, the pressing force of the slit squeegee 12 on the mask surface can be reduced and balls can be filled uniformly over a wide area along the rotation axis.

[0021] Furthermore, the rotation speed of the filling unit 3 can be low, which reduces scattering of the solder balls 11 caused by rotation. It is preferable to use a variable-speed motor for the filling unit 3 so that the rotation speed can be changed depending on the size and quantity of the solder balls 11. Furthermore, this device is equipped with a cleaning mechanism 25 for cleaning the back surface of the mask, which is mounted on the camera moving frame 24 and is configured to be able to move horizontally, just like the camera 18. A sweeper head 26 is also provided next to the filling head 2. This sweeper head 26 is used to sweep any remaining solder balls on the mask surface outside the printing area after the filling head 2 has operated and finished filling the solder balls 11. Details of the sweeper head 26 will be described later.

[0022] Figures 2 and 3 show schematic diagrams of the overall configuration of the fill head and sweeper head. Figure 2 shows the fill head moving to the left, and Figure 3 shows the fill head moving to the right.

[0023] As shown in Figure 2, the filling head 2 has the filling section 3 housed within the cover 4, and a piston rod 6a attached to a cylinder 5a is connected to a cover support member 10, so that it can move up and down together with the cover 4 by driving the cylinder 5a. A receiver for a piston rod 6b, which is shorter than the piston rod 6a attached to the cylinder 5b, is provided at the end of the cover support member 10, and by driving the cylinder 5b to determine the stopping position of the piston rod 6b, the lift height of the filling head 2 is determined when the solder ball filling section 3 is raised upward. The cover 4 is provided to prevent unfilled solder balls 11 from scattering outside the cover 4 when the filling section 3 rotates.

[0024] Furthermore, when in the printing state (when the filling section 3 is in contact with the mask surface), a gap is formed between this cover 4 and the surface of the mask 8. Furthermore, air supply sections 4a are provided at the front and rear of the cover 4, each equipped with an air supply port that blows air into the cover from below so that no solder balls remain on the mask surface outside the cover. The air blown into the cover 4 from the air supply section is exhausted from an exhaust port 4n provided in the cover support member 10. A mesh filter 4f is provided in this exhaust port 4n to prevent the solder balls 11 from scattering from inside the cover 4 to the outside.

[0025] As shown in FIG. 2, when the filling head 2 moves leftward, the filling unit 3 rotates clockwise. Also, as shown in FIG. 3, when the filling head 2 moves rightward, the filling unit 3 rotates counterclockwise. In this way, by rotating the filling unit 3 in accordance with the direction of movement so that the solder balls 11 are swept toward the forward direction of the filling head 2 and by blowing air through the cover, it is possible to prevent the scattering of the solder balls 11, ensure the amount of solder filled into the mask openings, and minimize the amount of excess solder balls remaining on the mask surface. Alternatively, a gas such as nitrogen, which retards the oxidation of the solder balls 11, may be blown into the cover 4 instead of air.

[0026] The filling section 3 is supported at both longitudinal ends of the cover 4. The cover 4 is supported via a cover support member 10 by a piston rod 6a constituting a cylinder 5a provided on the top of the head mounting frame 7. As shown in FIG. 1, this head mounting frame 7 is configured to move back and forth horizontally on a linear rail (not shown) by rotating a ball screw 2b provided on the printing machine main body using a motor 2g. The main body of the solder ball mounting device 1 is provided with a mask holding section that holds a mask frame 9 to which a mask 8 with multiple openings is attached. The substrate 20, which is the object to be printed, is held on the surface of a magnet 33 placed on a printing table 21 that is provided on the main body of the solder ball mounting device and is movable in the X, Yθ, and Z directions.

[0027] The magnet 33 provided on the printing table is for bringing the substrate 20 and the mask 8 into close contact with each other. The mask 8 is made of a magnetic material such as nickel, and when the printing table is raised and brought into contact with the mask surface, the magnetic force further improves the adhesion between the substrate 20 and the mask 8.

[0028] Furthermore, a sweeper head 26 is provided in parallel with the filling head 2 and is attached to a ball screw or timing belt (not shown). This sweeper head 26 is attached to a sweeper mounting frame 29, just like the filling head. A cylinder 5c, which is a drive source for moving a sweeper portion 27 of the sweeper head 26 up and down, is provided above the sweeper mounting frame 29. The sweeper portion 27 has a sweeper holder 4s attached to a sweeper support member, and a sweeper member is attached to the tip of the sweeper holder 4s.

[0029] This sweeper member is basically of approximately the same configuration as the filling member used in the solder ball filling head described above, and details will be described later. Also, like the filling head 2, the drive section of the sweeper head 26 is equipped with a cylinder 5d and a piston shaft 6d that determine the lift height of the sweeper head 26.

[0030] Figure 4 shows the sweeper head in operation. After the fill head 2 has finished filling the openings on the mask surface with solder balls 11, the sweeper head 26 moves the fill head 2 to the edge of the mask 8. Next, the sweeper head 26, which is waiting above the mask surface in its standby position, moves in the direction of the arrow (to the right in Figure 4) to collect the solder balls 11 remaining on the mask surface to the side of the mask surface where the fill head 2 is waiting. After that, the sweeper head is lowered, and the printing table is lowered to separate the mask from the board surface. The printing operation will be described in detail later.

[0031] Next, we will explain the general structure of the filling unit 3. Fig. 5 shows a front view of the filling unit, and Fig. 6 shows a cross-sectional view taken along line AA in Fig. 5. Fig. 7 shows a plan view of the slit squeegee, which is the filling member, before it is attached, and Fig. 10 shows the state in which the slit squeegee is fixed to the squeegee holder.

[0032] As shown in Figures 5 and 6, the filling unit 3 has a filling unit mounting member (hereinafter sometimes referred to as a squeegee holder 14) fixed to each side of an octagonal fixing member 15 attached to a rotating shaft 16 with bolts 17. The fixing member 15 is not limited to an octagonal shape, and may be a polygonal shape such as a hexagon, a diagonal or a dodecagon. Both ends of the rotating shaft 16 are supported by the cover 4 via bearings. A drive mechanism 13 is attached to one end of the rotating shaft 16, and the rotating shaft 16 can be rotated at a predetermined rotation speed by driving a motor constituting the drive mechanism 13. As shown in Figure 5, the filling unit 3 is elongated in the direction perpendicular to the moving direction of the filling head 2 (the width direction of the board). This length is longer than the width of the board 20 on which the solder balls are printed.

[0033] As a result, essentially, solder balls 11 can be filled onto almost all of the electrode portions of the substrate 20 simply by moving the solder ball filling head 2 horizontally once over the mask surface. The length of the filling member is Lj as shown in the figure, and the mask width Lm is made larger than Lj, while the substrate width Lt is made smaller than the mask width Lm and the filling member width Lj. In other words, the relationship is Lm ≧ Lj ≧ Lt.

[0034] As shown in FIG. 6, the squeegee holder 14 is fitted with a slit squeegee 12, which is made up of multiple thin strip-shaped members as shown in FIG. 7. The cross section of the squeegee holder 14 is trapezoidal, with the longer sides being rectangular. The holder is fitted with the shorter sides of the trapezoid facing the central axis. The trapezoidal cross section allows the slit squeegee 12 to be efficiently fitted in a semi-cylindrical shape. Furthermore, as shown in FIG. 10, magnets 31 are embedded in the rectangular portion of the squeegee holder 14 at predetermined intervals along the length. These magnets 31 are used to secure the slit squeegee 12 to the squeegee holder. Positioning pins 32 are provided between the magnets, and these pins fit into insertion holes 12H provided in fixing portions 12P provided at both widthwise ends of the slit squeegee 12.

[0035] As shown in Fig. 7, the slit squeegee 12 is made of a steel plate 0.05 to 0.1 mm thick, with main slits 12S spaced 0.1 mm to 0.3 mm apart, and is etched to form multiple wires at a line width of 0.1 mm and an inclination of θ = 5 to 35 degrees, excluding fixing portions 12P. The fixing portions 12P at both ends in the width direction are fixed to both sides of the squeegee holder 14. The slit squeegee 12 can be formed not only by etching but also by electroforming.

[0036] FIG. 15(a) is a plan view showing a conventional squeegee P12 in an expanded state, and FIG. 15(b) is an enlarged view showing the portion B enclosed by the dashed line in FIG. 15(a). This squeegee P12 is, for example, made of a steel plate 0.05 to 0.1 mm thick, with 0.1 to 0.3 mm wide slits P12S spaced 0.1 to 0.3 mm apart and inclined at θ = 5 to 35 degrees. Adjacent slits P12S form a strip-shaped member P12L with a width of 0.1 to 0.3 mm. The slits P12S are formed, for example, by etching a steel plate 0.05 to 0.1 mm thick. The squeegee P12 is attached in a semi-cylindrical shape, with fixing portions P12P provided at both ends of the squeegee P12 in the width direction fixed to both sides of a squeegee holder 14, and moves in the moving direction F indicated by the arrow.

[0037] By forming slits P12S in the steel plate, fixed portions P12P are provided at the front and rear of the steel plate in the traveling direction F, so that the narrow strip members P12L formed by adjacent slits P12S do not come apart, but the both side ends in the traveling direction F do come apart. Therefore, connecting portions P12C are formed at both side ends by the narrow strip members P12L that are continuously formed by the ends of the slits P12S, connecting them.

[0038] As described above, the conventional squeegee P12 presses its semi-cylindrical portion against the mask 8 to make contact and travel over the mask 8. However, even when this pressure is applied, the slits P12S in the center of the squeegee P122 open slightly, absorbing the pressure. However, because both ends of the squeegee P12 in the traveling direction F have connecting portions P12C that simply connect the strip-shaped members P12L together, the pressure cannot be absorbed and stress is applied to them. This has posed a problem in that the connecting portions can break due to this stress over long-term use.

[0039] Therefore, in one embodiment of the present invention, the slit squeegee 12 is configured as shown in Figure 7. In this figure, Figure 7(a) is a plan view showing one embodiment of the present invention, Figure 7(b) is a partially enlarged view of the portion indicated by the dashed line portion B in Figure 7(a), and Figure 7(c) is an enlarged view of a connecting portion 41 configured at the side end portion of the slit squeegee 12 in the traveling direction F. Note that Figure 9(a) is an enlarged perspective view of the end portion of the slit squeegee 12, and Figure 9(b) is an enlarged perspective view of the end portion of the slit squeegee 12 attached to the squeegee holder 14.

[0040] In this slit squeegee 12, the central portion 40 in the traveling direction F is made of a thin steel plate, for example, 0.05 to 0.1 mm thick, as in the conventional case, and main slits 12S, each 0.1 mm to 0.3 mm wide, are formed at intervals of 0.1 mm to 0.3 mm and tilted at θ = 5 degrees to 35 degrees. As a result, adjacent main slits 12S form narrow strip-shaped members 12L each 0.1 mm to 0.3 mm wide. These main slits 12S are formed, for example, by etching a steel plate 0.05 to 0.1 mm thick. The main difference from the conventional case is the configuration of the connecting portion 41. In the past, the thin strip-shaped members P12L were simply connected in succession by the connecting portion P12C, but according to this embodiment, a large number of auxiliary slits 42 are arranged alternately in the connecting portion 41, and these auxiliary slits 42 interrupt the continuity of the connecting portions 41 arranged on both side ends of the slit squeegee 12 in the direction of travel F of the slit squeegee 12.

[0041] 7(c), the embodiment has sub-slit 42a that is disposed over almost the entire area of ​​connecting portion 41 and has both ends closed, sub-slit 42b that has one end open at the end of slit squeegee 12 and the other end extending to the center of connecting portion 41, and sub-slit 42c that forms connecting portion 43a between the end of the center of sub-slit 42b. Sub-slits 42c located on both sides of sub-slit 42a communicate with each other on the main slit 12S side.

[0042] The thin strip-shaped members 12L formed by adjacent main slits 12S arranged in the central portion 40 of the slit squeegee 12 are connected at the ends of three adjacent ones, and this connecting portion 43b is further connected to the connecting portion 43a by the thin strip-shaped members 43L formed by the adjacent sub-slits 42c described above.

[0043] Due to the arrangement of these sub-slits 42a, 42b, and 42c, the continuity of connecting portion 41 (such as the continuity of conventional slit squeegee connecting portion P12C) is cut off in the direction F of travel of slit squeegee 12, as shown by connecting portion 43a, and the side ends of slit squeegee 12 are connected by connecting portion 43a and approximately diamond-shaped sub-strip members 43m formed by sub-slits 42a. With this configuration, connecting portion 41 has a substantially mesh or pantograph shape. As a result, even if stress is applied to both side ends of slit squeegee 12 when the semi-cylindrical portion of slit squeegee 12 is pressed against and comes into contact with mask 8 and travels over this mask 8, sub-slits 42a open slightly, absorbing this stress. In particular, by making the connecting portion 41 symmetrical like a pantograph or roughly diamond-shaped, the sub-slit 42a expands and contracts roughly uniformly in the left-right or up-down directions (arrow f) of the sub-slit 42a, and the amount of displacement when expanding and contracting is roughly uniform, which distributes and reduces the load and alleviates stress concentration, thereby contributing to extending the lifespan.

[0044] The connecting portions 43c connect adjacent main slits 12S as appropriate so that the strip-shaped members 12L formed by adjacent main slits 12S do not come apart. In the embodiment, the connecting portions 43c are arranged in a staggered pattern as a whole, but this is not limitative and they may be arranged as appropriate so that the main slits 12S do not come apart.

[0045] Figure 8 is a simplified view to facilitate understanding of the slit squeegee 12 of this embodiment, and Figure 8(a) is similar to Figure 7(c). Figure 8(b) is a view showing the portion indicated by X in Figure 8(a) and is a schematic diagram in which the thin strip-shaped members formed as a result of the various slits described above are highlighted by thick lines. Figures 8(c) and 8(d) are views for explaining the state in which the connecting portion 41 is deformed by stress applied thereto. In these figures, the same reference numerals as those in Figure 7 indicate the same parts.

[0046] That is, under normal circumstances, the shape of the slit squeegee 12 is stable as shown in Figures 8(a), 8(b), and 8(c), but when the slit squeegee 12 is pressed onto the mask 8 during the solder ball mounting operation and stress is applied to both side ends of the slit squeegee 12, the connecting parts 41 at the side ends are pulled up and down as shown in Figure 8(d). As a result, a force is applied to the roughly diamond-shaped sub-strip members 43m formed by the sub-slits 42a in the direction shown by arrow f, causing the sub-slits 42a to open and ultimately absorbing this stress.

[0047] Furthermore, the connecting portion 41 of the slit squeegee 12 is flexible in response to the applied stress, and as a result, absorbs this stress.

[0048] Next, a method for attaching the slit squeegee 12 to the squeegee holder 14 will be described with reference to Figure 10. Figure 10(a) shows a perspective view, and Figure 10(b) shows a cross-sectional view.

[0049] The squeegee holder 14 is provided with a plurality of positioning pins 32 spaced at predetermined intervals, and magnets 31 are embedded between the positioning pins 32. When attaching the slit squeegee 12 to each squeegee holder 14, the positioning pins 32 on both sides of the squeegee holder 14 are inserted into the insertion holes 12H of the slit squeegee 12. Thereafter, by inserting the positioning pins 32 into the insertion holes 30H provided in the squeegee presser plate 30 made of a magnetic material, the magnetic force acts on the presser plate 30 and the slit squeegee 12 can be fixed in place. In this way, positioning can be easily performed, and the slit squeegee 12 can be easily attached and removed.

[0050] Furthermore, this structure reduces the required fixing space, allowing for smaller spacing between squeegee holders 14. The narrow strip members 12L that make up the slit squeegee 12 are attached so as to be inclined in a predetermined direction relative to the longitudinal direction and so as to form a space relative to the squeegee holder 14. In other words, the slit squeegee 12 is composed of narrow strip members 12L that are semi-spiral in the longitudinal direction. Furthermore, as shown in FIG. 5, the narrow strip members 12L that make up the slit squeegee 12 are attached so that the inclination directions of the narrow strip members 12L are opposite for each of the adjacent squeegee holders 14. By alternately changing the inclination direction of the slit squeegees 12 in this way, excess solder balls that are not filled into the mask openings and remain on the mask surface can be efficiently collected toward the filling section.

[0051] Next, a series of operations for printing solder balls will be described with reference to FIGS.

[0052] First, the substrate 20, on which flux is printed on the electrode portions, is carried into the solder ball mounting device and placed on the magnet 33 on the printing table 21. The printing table 21 and the magnet 33 are provided with multiple suction ports that supply negative pressure, and by supplying negative pressure to these ports, the substrate 20 is held on the magnet 33 so that it does not move.

[0053] Next, the alignment marks provided on the surface of the substrate 20 and the alignment marks provided on the mask 8 are imaged using an alignment camera 18. The imaged data is sent to a control unit (not shown), which processes the image to determine the amount of misalignment, and based on the result, the printing table 21 is moved in a direction that corrects the misalignment by a horizontal movement mechanism (not shown).

[0054] Once the alignment is complete, the drive unit 22, which is the mechanism for raising the printing table 21, is driven to raise the printing table 21 and bring it into contact with the back surface of the mask 8. At this time, the magnets 33 on the printing table 21 allow the mask 8 to adhere closely to the substrate 20.

[0055] Next, a solder ball supply device (not shown) supplies solder balls 11 to the front portion of the initial position (printing start position) of the filling head 2 on the surface of the mask 8 in the moving direction. After that, the filling head 2 is moved horizontally to the printing start position and lowered to the mask surface. At this time, the filling unit 3 is lowered to a position where a predetermined pressing force acts on the mask surface.

[0056] Next, as shown in (1) of Figure 11 (or Figure 6), the filling unit 3 is rotated clockwise. Then, the solder ball filling head 2 is moved horizontally over the mask surface in the direction of the arrow in the figure. During this movement, air is blown from the air supply unit 4a toward the inside of the cover 4, which has a slit squeegee. By rotating the filling unit 3 in this way, the solder balls 11 are pushed into the mask openings, adhering to the flux on the board 20. Outside the openings, the filling unit 3 moves the solder balls 11 in the direction of travel over the mask surface. When the filling unit 3 reaches the edge of the board, the rotation of the filling unit 3 is stopped, the air supply from the air supply unit 4a is stopped, and the filling unit 3 is raised. Then, the filling head 2 is moved leftward as shown in (2) of the figure. By moving the filling head in this way, the filling head 2 is positioned behind the position of the next solder ball 11 to be filled. Once the movement is complete, the filling unit 3 is again lowered to a position where it contacts the mask surface with a predetermined pressing pressure. Then, as shown in FIG. 11 (3), the air supply unit resumes supplying air into the cover, and the filling unit 3 is rotated counterclockwise to move the filling head 2 to the right side of the figure. When the filling head 2 reaches a position close to the edge of the board, the air supply unit is stopped, and the filling unit 3 of the filling head 2 is raised as shown in FIG. 11 (4), moved further to the right, and lowered as shown in FIG. 11 (5), so that the remaining solder ball 11 is positioned to the left of the filling unit 3. The filling unit is then lowered onto the mask surface and placed in a standby state. In this embodiment, the filling head 2 makes one reciprocating motion to fill the mask opening with solder balls, ensuring reliable filling.

[0057] In steps (1) to (4) of FIG. 11, the sweeper head 26 waits with the sweeper portion 27 lowered on the surface of the mask 8. Next, as shown in FIG. 11(6), the sweeper head 26 is moved to the right side of the figure (the side where the filling head 2 is waiting). It is moved to the vicinity of the waiting position of the filling head 2. As shown in FIG. 12(7), when the sweeper head 26 reaches the vicinity of the filling head 2, the sweeper portion 27 is raised and separated from the mask surface. Then, the sweeper head 26 is returned to the initial waiting position. When it returns to the waiting position as shown in FIG. 12(8), the sweeper portion 27 is again lowered onto the mask surface and brought into contact with it with a predetermined contact pressure. As shown in FIG. 12(9), it is again moved over the mask surface to the vicinity of the waiting position of the filling head 2. This movement allows the solder balls 11 remaining on the mask surface to be collected in a position completely off the substrate surface. When this cleaning is completed, the printing table 21 is lowered to separate the substrate 20 from the mask surface, while the filling head 2 and the sweeper head 26 remain in contact with the mask surface.

[0058] In this explanation, the sweeper head 26 is operated twice, but by operating it multiple times, it is possible to reliably move the remaining solder balls on the mask surface to a location away from the substrate position.

[0059] Furthermore, in this embodiment, after filling the mask openings with solder balls 11 using the filling head 2, the sweeper head 26 is operated to clean the remaining solder balls on the mask surface down to the mask surface away from the substrate, but if the filling head of the embodiment is used, it is possible that there will be almost no solder balls remaining on the mask surface, making cleaning unnecessary, and there may be cases where a sweeper head is not necessary. Alternatively, the filling head 2 and sweeper head 26 can be used as an integrated head.

[0060] 11(6) to 12(9), when the filling head 2 is on standby, air or nitrogen may be blown from the air supply unit 4a toward the inside of the cover 4. This makes it possible to prevent the solder balls 11 from leaking out of the cover, and delay the oxidation of the solder balls 11.

[0061] Next, the printed state of the printed substrate 20 is photographed with a camera to check for defects. After checking for defects, the cleaning mechanism 25 is activated to clean the back surface of the mask. If defects are found, the substrate 20 is transported to a repair section where the defects are repaired. After the defects are repaired, the substrate is transported to a reflow section where the solder balls are melted and fixed.

[0062] The above describes the general process of printing solder balls, but the repair and reflow sections are performed using separate equipment from the above-mentioned equipment, so detailed explanations are not provided.

[0063] During this process, by using the solder ball supply head of the present invention, it is possible to reliably supply solder balls with a small diameter onto the flux through the mask openings. [Example]

[0064] 13 is a plan view showing another embodiment of the slit squeegee of the present invention. In embodiment 1, connecting portions 41 formed on both end portions in the traveling direction F of slit squeegee 12 were configured to be expandable and contractible in the traveling direction F by rationally arranging auxiliary slits, but in this embodiment, connecting portions 412 are configured from an elastic body, and are expandable and contractible in the traveling direction F.

[0065] Here, a conventional slit squeegee P12 is used as the slit squeegee 122. Elastic resin 50 is pressed onto both side ends of the slit squeegee 122 in the traveling direction F. Subsequently, this elastic resin 50 is polished until it is as thin as possible, until it is the same thickness as the thin steel plate that makes up the slit squeegee P12. After that, the connecting portion P12C is cut along line YY, and the connecting portion 412 is configured to be expandable and contractible in the traveling direction F due to the elastic force of the elastic body. Other examples of joining elastic bodies include the example shown in Japanese Patent Application Laid-Open No. 2006-294527.

[0066] In this way, the slit squeegee 122, as described above, presses the semi-cylindrical portion against the mask 8 to make contact and travels over the mask 8, but even when this pressure is applied to the central portion 402, the main slit 12S opens slightly, absorbing the pressure. Furthermore, because the narrow strip members 12L are connected to both ends of the slit squeegee 122 in the traveling direction F by elastic bodies, the elastic bodies expand and contract under the pressure, absorbing stress. Therefore, damage to the connecting portions 412 present at both ends of the slit squeegee 122 can be prevented for a longer period of time, and a squeegee for a solder ball placing device and a solder ball placing device that can withstand long-term use can be obtained.

[0067] The slit squeegee 122 is attached to the squeegee holder 14 in the same manner as the slit squeegee 12 . [Example]

[0068] 14 is a plan view showing yet another embodiment of the slit squeegee. In embodiment 1, connecting portions 41 formed on both end portions in the traveling direction F of slit squeegee 12 were configured to be expandable and contractible in the traveling direction F by rationally arranging auxiliary slits, but in this embodiment, connecting portions 413 are configured from metal plates 60 having elasticity, and connecting portions 413 are configured to be expandable and contractible in the traveling direction F.

[0069] Here, the slit squeegee 123 uses a conventional slit squeegee 12, as in Example 2. Elastic metal plates 60 are joined to both end portions of the slit squeegee 123 in the traveling direction F. Subsequently, the elastic metal plates 60 are rolled and polished until they are as thin as possible, similar to the thin steel plates that make up the slit squeegee 12. After that, the connecting portions P12C are cut along line YY, and the connecting portions 413 are configured to be expandable and contractible in the traveling direction F due to the elasticity of the elastic metal plates 60. Other examples of elastic metal plates and joining thereof include those disclosed in Japanese Patent Application No. 2007-546902 and Japanese Patent Laid-Open No. 02-107884.

[0070] In this way, the slit squeegee 123, as described above, presses the semi-cylindrical portion onto the mask 8 to come into contact with it and moves over the mask 8, but even when this pressing force is applied, the main slit 12S of the connecting portion 413 opens slightly, absorbing the pressing force. Furthermore, since the narrow strip-shaped members 12L are connected to both side ends of the slit squeegee 123 in the moving direction F by the elastic metal plates 60, the elastic metal plates 60 expand and contract due to this pressing force, absorbing stress.

[0071] Therefore, damage to the connecting portions 413 present at both end portions of the slit squeegee 123 can be prevented for a longer period of time, and a squeegee for a solder ball placing device and a solder ball placing device that can withstand long-term use can be obtained.

[0072] The slit squeegee 123 is attached to the squeegee holder 14 in the same manner as the slit squeegee 12 .

[0073] As is clear from the above description of the embodiments, according to the present invention, the squeegee is formed in the shape of a thin plate, has a plurality of slits at a predetermined angle relative to the direction of movement when the solder balls are placed, and has connecting portions at both ends in the direction of movement that connect the thin plates separated by the slits, and these connecting portions are formed to be flexible at least in the direction of movement. Therefore, even if stress is applied to both ends of the squeegee when it presses against and contacts the mask and moves over the mask, this stress is absorbed by its flexibility. Therefore, damage to the connecting portions at both ends of the squeegee can be prevented for a long period of time, and a squeegee for a solder ball placing device and a solder ball placing device that can withstand long-term use can be provided. In other words, the frequency of replacement due to damage to the squeegee's ends can be reduced.

[0074] As explained in the examples, it is desirable to form the squeegee in a semi-cylindrical shape and use it when mounting the solder balls. By pressing the semi-cylindrical cylindrical portion against the mask, the cylindrical portion deforms and adheres closely to the surface of the mask. This configuration extends the life of the squeegee and improves its functionality.

[0075] Furthermore, as shown in the examples, it is desirable to form the connecting parts from an elastic body or a metal plate having elasticity in order to allow the connecting parts to expand and contract freely. This configuration further extends the lifespan.

[0076] In the examples, in the explanation of the alternating arrangement of sub-slits, sub-slits that are open at the ends and sub-slits that are closed at the ends are arranged alternately, but here, alternating arrangement means not only alternating arrangement one by one, but also alternating arrangement of multiple, or one and then two, etc., and the combination can be selected as needed.

[0077] In addition, in the squeegee of this embodiment, it is desirable that the narrow strip members formed by adjacent main slits are appropriately connected to the adjacent narrow strip members at the main slit connecting portion in the central portion facing the substrate surface.

[0078] Furthermore, the squeegee has mounting portions at both ends in the direction of travel, and by attaching the mounting portions to the squeegee holder to form a semi-cylindrical shape, the life of the squeegee can be extended and its functionality can be improved. [Explanation of symbols]

[0079] 1...solder ball mounting device, 2...filling head, 3...filling section, 4...cover, 5...head up / down drive mechanism, 7...head mounting frame, 8...mask, 10...cover support member, 10a...sweeper support member, 11...solder ball, 12...slit squeegee, 14...squeegee holder, 16...rotating shaft, 18...camera, 20...substrate, 21...printing table, 31...magnet, 32...positioning pin, 33...magnet, 40, 402, 403...center of squeegee, 41, 412, 413...squeegee connecting section, 42a...sub-slit closing at end, 42b...sub-slit opening at end, 50...elastic resin, 60...metal plate with elastic force

Claims

1. A squeegee of a solder ball mounting device is provided on a surface of a substrate on which a plurality of electrodes are formed, the squeegee having openings at positions corresponding to the electrodes, and solder balls are supplied onto the mask through the openings to mount the solder balls on the electrodes, a plurality of slits formed in a thin plate shape and having a predetermined angle with respect to the direction of movement of the solder balls when they are mounted; connecting portions for connecting the thin plates separated by the slits at both end portions in the traveling direction; The squeegee of the solder ball mounting device is characterized in that the connecting portion is formed so as to be expandable and contractible at least in the direction of movement.

2. 2. The squeegee of claim 1, The squeegee for a solder ball mounting device is characterized in that the squeegee is used in a semi-cylindrical state.

3. 2. The squeegee of claim 1, A squeegee for a solder ball mounting device, characterized in that auxiliary slits are arranged alternately in the connecting portions so that the connecting portions are not continuous in the traveling direction, thereby making the squeegee flexible at least in the traveling direction.

4. 4. The squeegee of claim 3, A squeegee for a solder ball mounting device, characterized in that the connecting portion is formed to be freely expandable and contractible at least in the direction of travel by alternating sub-slits that open at the end and sub-slits that close at the end.

5. 2. The squeegee of claim 1, A squeegee for a solder ball loading device, characterized in that, in a central portion corresponding to the substrate, adjacent narrow strip members formed by the slits are connected to the adjacent narrow strip members by a slit connecting portion.

6. 2. The squeegee of claim 1, A squeegee for a solder ball loading device, characterized in that it has attachment portions at both ends in the moving direction, and is formed into a semi-cylindrical shape by attaching the attachment portions to a squeegee holder.

7. 2. The squeegee of claim 1, The squeegee of the solder ball loading device is characterized in that the connecting portion is formed of an elastic body so as to be flexible in the direction of movement.

8. 8. The squeegee of the solder ball mounting device according to claim 7, The squeegee of the solder ball loading device is characterized in that the elastic body is formed of a metal plate having elasticity, and is therefore formed to be flexible at least in the direction of movement.

9. A solder ball mounting device is provided for a substrate surface on which a plurality of electrodes are formed and on which flux is applied, the substrate surface being provided with a mask having openings at positions corresponding to the electrodes, and the mask is used to mount solder balls supplied onto the mask by a semi-cylindrical squeegee having a thin plate with a plurality of slits through the openings onto the electrodes, The squeegee is formed in a thin plate shape, a plurality of slits at a central portion corresponding to the substrate surface and at a predetermined angle with respect to the direction of travel; connecting portions for connecting the thin plates separated by the slits at both end portions in the traveling direction; The solder ball mounting device is characterized in that the connecting portion is formed to be expandable and contractible at least in the direction of movement.

10. 10. The solder ball mounting device according to claim 9, A solder ball mounting device characterized in that auxiliary slits are arranged alternately at the connecting portions of the squeegee so that the connecting portions are not continuous in the direction of travel, thereby making the device flexible to expand and contract at least in the direction of travel.

11. 11. The solder ball mounting device according to claim 10, A solder ball mounting device characterized in that the connecting portion of the squeegee is formed to be freely expandable at least in the direction of travel by alternately arranging sub-slits that open at the end and sub-slits that close at the end.

12. 10. The solder ball mounting device according to claim 9, A solder ball mounting device characterized in that, at the center of the squeegee corresponding to the substrate surface, adjacent strip-shaped members formed by the slits are connected to adjacent strip-shaped members by a slit connecting portion.

13. 10. The solder ball mounting device according to claim 9, The solder ball loading device is characterized in that the squeegee has attachment portions at both ends in the moving direction thereof, and the semi-cylindrical shape is formed by attaching the attachment portions to a squeegee holder.

14. 10. The solder ball mounting device according to claim 9, The solder ball mounting device is characterized in that, by pressing the semi-cylindrical cylindrical portion against the mask, the cylindrical portion is deformed and comes into close contact with the surface of the mask.

15. 10. The solder ball mounting device according to claim 9, The solder ball mounting device is characterized in that the connecting portion of the squeegee is formed of an elastic body, and is therefore formed to be flexible at least in the direction of movement.

16. 10. The solder ball mounting device according to claim 9, The solder ball mounting device is characterized in that the connecting portion of the squeegee is formed of a metal plate having elasticity, and is therefore formed to be flexible at least in the direction of movement.

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