Mask for arrangement

Abstract

The invention provides a mask for arrangement, which can quickly and smoothly insert solder balls into through holes compared with a conventional mask for arrangement. This alignment mask is provided with through-holes (12) corresponding to a predetermined alignment pattern. The opening diameter (D1) of the upper opening (17) of the through hole (12) is configured from a circular hole having a diameter larger than the diameter (d) of the solder ball (2). On the inner peripheral surface (19) of the through hole (12), one or more positioning bodies (20) for guiding the solder ball (2) inserted into the through hole (12) toward a predetermined position and holding and positioning the solder ball (2) at the predetermined position are formed so as to extend toward the center of the hole.

Description

Technical Field

[0001] The present invention relates to a solder ball arrangement mask used for producing solder bumps of a BGA (Ball Grid Array) system. Background Art

[0002] Conventionally, the BGA (Ball Grid Array) method is known as a method for forming solder bumps. This BGA method involves applying flux to electrodes on a substrate such as a wafer, flexible substrate, or rigid substrate, followed by a printing step in which solder balls are arranged on the flux, and then heating and dissolving the solder balls. A known method for arranging solder balls on a substrate is the insertion method using a mask. This method uses an insertion mask (hereinafter referred to as the "mask") with positioning holes that allow solder balls to be inserted, corresponding to the arrangement pattern of the substrate's electrodes. Specifically, a mask is arranged on the substrate so that the holes align with the electrodes. A sweeping tool, such as a squeegee or brush, is then used to sweep the solder balls supplied to the mask, inserting one solder ball into each through-hole. This secures the solder balls to the flux and positions them at predetermined locations on the substrate.

[0003] A well-known example of an alignment mask is the one disclosed in Patent Document 1. The through-holes in the mask of Patent Document 1 consist of straight holes with a constant through-hole direction. Furthermore, the opening diameter of the straight holes is set slightly larger than the diameter of the solder balls. Solder balls supplied to the mask are inserted into each through-hole through the upper opening of the through-hole and positioned at a predetermined position on the inner circumference of each through-hole. Patent Document 2, also filed by the present patent applicant, also discloses an alignment mask with a similar structure.

[0004] Prior art literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-287215

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2006-324618

[0007] A solder ball supplied to the mask and swept by the sweeping tool is introduced into the through-hole when its center of gravity is above the upper opening of the through-hole. However, in the masks of Patent Documents 1 and 2, the diameter of the through-hole's upper opening is slightly larger than the diameter of the solder ball. This reduces the chances of the solder ball's center of gravity being above the upper opening, and the solder ball's entry into the through-hole can be delayed. Furthermore, a solder ball dropped into the through-hole can come into contact with the inner circumference of the through-hole and become stuck, preventing the solder ball from being smoothly inserted into the through-hole. This is also disadvantageous. Summary of the Invention

[0008] An object of the present invention is to provide an array mask capable of more quickly and smoothly placing solder balls into through-holes.

[0009] The present invention is directed to an alignment mask for placing solder balls 2 at predetermined positions on a substrate 3 by inserting them into through-holes 12 corresponding to a predetermined arrangement pattern. The alignment mask is characterized in that one or more positioning members 20 are formed on the inner circumference 19 of through-holes 12, each of which is a circular hole having an opening diameter D1 larger than the diameter d of the solder balls 2. These positioning members 20 are used to guide solder balls 2 inserted into through-holes 12 toward predetermined positions and to hold and position the solder balls 2 in the predetermined positions.

[0010] The positioning body 20 is composed of a protrusion extending in the upper and lower directions along the inner circumferential surface 19 of the through hole 12, and is composed of a receiving portion 21 and an introduction portion 22, wherein the receiving portion 21 is arranged on the side of the lower opening 18 of the through hole 12, and receives and holds the solder ball 2 in the through hole 12, and the introduction portion 22 is arranged on the side of the upper opening 17 of the through hole 12, and guides the solder ball 2 to a predetermined position in the through hole 12.

[0011] The introduction portion 22 is formed so that its protruding dimension gradually increases toward the lower opening 18. The upper end of the introduction portion 22 is formed by a portion of the opening edge of the upper opening 17 of the through hole 12, which is formed by a circular hole.

[0012] Three or more positioning bodies 20 are provided on the inner peripheral surface 19 of the through hole 12. When the inner peripheral surface 19 of the through hole 12 is divided into two half peripheral surfaces 19a and 19b at an arbitrary position, the positioning body 20 is provided on both the half peripheral surfaces 19a and 19b.

[0013] The positioning bodies 20 are provided at equal intervals in the circumferential direction of the inner peripheral surface 19 of the through hole 12 .

[0014] The positioning body 20 is provided on the inner peripheral surface 19 of the through hole 12 located on the downstream side in the moving direction of the scanning tool S for moving on the alignment mask to drop the solder ball 2 into the through hole 12 .

[0015] When viewed from above, assuming an imaginary line V passing through the center of the through hole 12, a positioning body 20 is provided at a position where the imaginary line V pointing in the moving direction of the sweeping tool S intersects the inner peripheral surface 19 of the through hole 12 on the downstream side of the moving direction of the sweeping tool S.

[0016] The positioning body 20 , which is formed of ridges, has a fan-shaped cross section perpendicular to the vertical direction. The positioning body 20 is provided so that the long arc of the fan-shaped shape faces the inner peripheral surface 19 of the through hole 12 .

[0017] The positioning body 20 , which is formed of a protrusion, has a trapezoidal cross-section perpendicular to the vertical direction. The positioning body 20 is provided so that the long bottom side of the trapezoid faces the inner peripheral surface 19 of the through hole 12 .

[0018] The cross-section of the positioning body 20 formed of the protrusions perpendicular to the vertical direction is formed into a sector shape with a rounded main portion. The positioning body 20 is provided so that the sector arc faces the inner peripheral surface 19 of the through hole 12 .

[0019] The positioning body 20 formed of the protrusions has a fan-shaped cross section perpendicular to the vertical direction. The positioning body 20 is provided so that the fan-shaped arc faces the inner peripheral surface 19 of the through hole 12 .

[0020] Effects of the Invention

[0021] In the alignment mask of the present invention, one or more positioning members 20 are formed extending toward the center of the inner circumferential surface 19 of a through-hole 12, which is a circular hole having an opening diameter D1 of an upper opening 17 larger than the diameter d of the solder ball 2. These positioning members 20 are used to guide the solder ball 2 introduced into the through-hole 12 toward a predetermined position and to hold and position the solder ball 2 there. Thus, by guiding and holding the solder ball 2 at the predetermined position within the through-hole 12 using one or more positioning members 20 extending from the inner circumferential surface 19 of the through-hole 12, the opening diameter D1 of the upper opening 17 of the through-hole 12 can be made larger than the diameter d of the solder ball 2 by the extension of the positioning members 20, compared to conventional masks that hold the solder ball within the inner circumferential surface of the through-hole. This increases the chance that the center of gravity of the solder ball 2 swept by the scanning tool S will be located above the upper opening 17 of the through-hole 12, thereby facilitating the introduction of the solder ball 2 into the through-hole 12. Furthermore, if the opening diameter D1 of the upper opening 17 of the through-hole 12 is formed to be larger than the diameter d of the solder ball 2, a gap can be formed between the peripheral surface of the solder ball 2 dropped into the through-hole 12 and the inner peripheral surface 19 of the through-hole 12. This can prevent the solder ball 2 dropped into the through-hole 12 from coming into contact with the inner peripheral surface 19 and becoming stuck. In summary, according to the alignment mask 1 of the present invention, the solder ball 2 can be dropped into the through-hole 12 more quickly and smoothly than conventional alignment masks. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a plan view showing a through hole of the alignment mask according to the first embodiment of the present invention.

[0023] Figure 2 It is a perspective view showing the entire alignment mask and the workpiece, and a plan view showing a portion of the alignment mask in enlarged form.

[0024] Figure 3 It is a longitudinal sectional front view of the main part of the alignment mask.

[0025] Figure 4 It is a longitudinal sectional view showing the positioning body.

[0026] Figure 5 It is a top view showing the positioning body.

[0027] Figure 6 It is a plan view showing a through hole of an alignment mask according to a second embodiment of the present invention.

[0028] Figure 7 It is a plan view showing a through hole of an alignment mask according to a third embodiment of the present invention.

[0029] Figure 8 It is a plan view showing a through hole of an alignment mask according to a fourth embodiment of the present invention.

[0030] Figure 9 It is a plan view showing a through hole of an alignment mask according to a fifth embodiment of the present invention.

[0031] Figure 10 It is a plan view showing a positioning body of an alignment mask according to a sixth embodiment of the present invention.

[0032] Figure 11 It is a plan view showing a positioning body of an alignment mask according to a seventh embodiment of the present invention.

[0033] Figure 12 It is a plan view showing a positioning body of an alignment mask according to an eighth embodiment of the present invention.

[0034] Figure 13 It is a longitudinal sectional view showing a positioning body of an alignment mask according to a ninth embodiment of the present invention.

[0035] Figure 14 It is a longitudinal sectional view showing a positioning body of an alignment mask according to a tenth embodiment of the present invention.

[0036] Figure 15 It is a longitudinal sectional view showing a positioning body of an alignment mask according to an eleventh embodiment of the present invention.

[0037] Figure 16 It is a longitudinal sectional view showing a positioning body of an alignment mask according to a twelfth embodiment of the present invention.

[0038] Figure 17 It is a longitudinal sectional view showing a positioning body of an alignment mask according to a thirteenth embodiment of the present invention.

[0039] Figure 18It is a longitudinal sectional view showing a positioning body of an alignment mask according to a fourteenth embodiment of the present invention.

[0040] Figure 19 It is a longitudinal sectional view showing a positioning body of an alignment mask according to a fifteenth embodiment of the present invention.

[0041] In the figure: 1—arrangement mask, 2—solder ball, 3—substrate, 12—through hole, 17—upper opening, 18—lower opening, 19—inner circumference, 19a—semi-circumference of the through hole, 19b—semi-circumference of the through hole, 20—positioning body, 21—receiving part (receiving rib), 22—introduction part (introduction rib), D—diameter of solder ball, D1—opening diameter of upper opening, S—sweeping tool (scraper brush), V—imaginary line passing through the center of the through hole. DETAILED DESCRIPTION

[0042] (First embodiment) Figures 1 to 4 The first embodiment of the solder ball arrangement mask according to the present invention is shown. Figure 1 and Figure 3 The cross arrows and their surrounding areas represent front, back, left, right, and top and bottom. The top and bottom directions correspond to the thickness of the alignment mask, and dimensions such as thickness in the figures are schematic and do not represent actual dimensions. This alignment mask (hereinafter referred to as the mask) 1 is used to align solder balls 2 during the fabrication of solder bumps in a BGA system. Solder balls 2 are spheres with a diameter d of 100 μm or less.

[0043] exist Figure 2 In the figure, reference numeral 3 represents a substrate (workpiece) on which the solder balls 2 are mounted using a mask 1. The substrate 3 is formed by mounting a plurality of semiconductor chips 5 on a base 4 of a glass epoxy substrate, wiring them by wire bonding, and then sealing them by transfer molding. On the upper surface of the substrate 3, electrodes 6 serving as input and output terminals are formed in a predetermined arrangement pattern so as to surround the semiconductor chips 5. After the solder bumps are made, the substrate 3 is cut into individual pieces to form individual LSI chips. Each electrode 6 is formed in a circular shape, and its diameter is set to be approximately the same as the diameter d of the solder ball 2. On the electrode 6, a flux 7 for temporarily fixing and adhering the solder ball 2 is applied in a printing process before the arrangement of the solder ball 2. In addition, each electrode 6 is sometimes formed in a rectangular shape. In this case, the diameter d of the solder ball 2 is set to be approximately the same as the length dimension of the long side of the rectangle.

[0044] like Figure 2As shown, the mask 1 consists of a mask body 10 formed by electroforming using copper, nickel, nickel-cobalt, or other electrodeposited metals, and a frame 11 joined to surround the mask body 10. The frame 11 is a quadrilateral whose outer shape matches the outer shape of the mask body 10. The metal constituting the frame 11 is preferably a metal (low thermal expansion material) with a lower thermal linear expansion coefficient than the metal constituting the mask body 10, such as 42 alloy, Invar, or SUS430. In addition to low thermal expansion materials, other materials can be used, such as stainless steel, aluminum, and aluminum alloys. On the disk surface of the mask body 10, which is surrounded by the frame 11, a pattern area 13 is formed, corresponding to each semiconductor chip 5, with a plurality of independent through-holes 12 for inserting solder balls 2. The frame 11 serves both as a retaining member for the mask body 10 and as a reinforcement for the mask body 10.

[0045] When the solder balls 2 are arranged, the mask 1 is placed on the substrate 3. At this time, in order to support the mask body 10 in a posture of floating from the upper surface of the substrate 3, a protrusion 14 is provided on the lower surface of the mask body 10. Specifically, Figure 3 As shown, on the lower surface of the mask body 10, i.e., the surface facing the substrate 3, a plurality of protrusions 14 are integrally formed on the mask body 10, projecting downwardly, ensuring a spaced relationship with the substrate 3. Each protrusion 14 is cylindrical, with a height dimension approximately equal to or slightly smaller than half the diameter d (radius) of the solder ball 2. The provision of these protrusions 14 prevents the flux 7 from adhering to the mask body 10 and the inner circumferential surface 19 of the through-hole 12 when the mask 1 is placed on the substrate 3. The protrusions 14 are not limited to being formed independently; they can also be arranged in a lattice frame pattern surrounding the pattern area 13. Furthermore, while the protrusions 14 are integrally formed with the mask body 10, they can also be formed separately from the mask body 10 and integrally joined to the mask body 10. The shape of the protrusions 14 is not limited to being cylindrical; they can also be rib-shaped.

[0046] like Figure 1 and Figure 3As shown, multiple independent through-holes 12 are formed in substrate 3 at locations corresponding to the arrangement pattern of electrodes 6 of each semiconductor chip 5. Each through-hole 12 is a linear circular hole extending vertically (through the thickness direction) through mask body 10, with circular openings on the upper and lower surfaces of mask body 10. The opening diameter D1 of upper opening 17 of through-hole 12, which opens on the upper surface of mask body 10, and the opening diameter D2 of lower opening 18, which opens on the lower surface of mask body 10, are the same. Both openings 17 and 18 are larger in diameter than the diameter d of solder ball 2. Specifically, the opening diameters D1 and D2 of both openings 17 and 18 are preferably set to approximately 1.5 times the diameter d of solder ball 2, and more preferably approximately 1.25 times the diameter d of solder ball 2.

[0047] like Figure 1 As shown, one or more positioning bodies 20 are formed on the inner circumferential surface 19 of the through-hole 12, extending toward the center of the hole. These positioning bodies 20 are used to guide the solder ball 2 inserted into the through-hole 12 toward a predetermined position and to hold and position the solder ball 2 there. In this embodiment, three positioning bodies 20 are arranged at equal intervals along the circumference of the inner circumferential surface 19 of the through-hole 12. One of the three positioning bodies 20 is provided on the inner circumferential surface 19 of the through-hole 12. The through-hole 12 is located downstream of the movement direction of a squeegee brush (sweeping tool) S, which moves across the mask 1 during the solder ball 2 alignment operation to cause the solder ball 2 to fall into the through-hole 12.

[0048] Specifically, as the squeegee brush S moves from the front to the rear of the mask 1, one of three positioning bodies 20 is positioned at the intersection of an imaginary line V extending in the direction of movement of the squeegee brush S (front-to-back direction) and the inner circumferential surface 19 of the through-hole 12 downstream of the squeegee brush S, assuming a line V passing through the center of the through-hole 12 in a top view. The remaining two positioning bodies 20 are positioned 120 degrees and 240 degrees clockwise from the previous positioning body 20, respectively, relative to the center of the through-hole 12. For example, if the diameter d of the solder ball 2 is set to 1 and the opening diameter D1 (opening diameter D2) of the upper opening 17 (lower opening 18) is set to 1.25 (1.25 times the diameter d of the solder ball 2), the protrusion of each positioning body 20 is preferably set to 0.125 or less.

[0049] When three (or more) positioning bodies 20 are provided on the inner circumferential surface 19 of the through hole 12, they do not necessarily need to be provided at equal intervals along the circumference of the inner circumferential surface 19 of the through hole 12. However, when the inner circumferential surface 19 of the through hole 12 is divided into two half-circumferential surfaces 19a and 19b at any position, it is preferable that positioning bodies 20 be provided on each half-circumferential surface 19a and 19b. In this embodiment, when the inner circumferential surface 19 of the through hole 12 is divided into front and rear half-circumferential surfaces 19a and 19b, two positioning bodies 20 are provided on the front half-circumferential surface 19a, and one positioning body 20 is provided on the rear half-circumferential surface 19b.

[0050] like Figure 3 and Figure 4 As shown, each positioning member 20 comprises a protrusion extending vertically along the inner circumferential surface 19 of the through-hole 12. The positioning members 20 are composed of a receiving rib (receiving portion) 21 and an introduction rib (introduction portion) 22. The receiving rib (receiving portion) 21 is located on the lower opening 18 side of the through-hole 12 and receives and holds the solder ball 2 within the through-hole 12. The introduction rib (introduction portion) 22 is located on the upper opening 17 side of the through-hole 12 and guides the solder ball 2 to a predetermined position within the through-hole 12. The receiving rib 21 is a protrusion with a constant protrusion dimension, extending from the edge of the lower opening 18 of the through-hole 12 to the center in the vertical direction. The receiving rib 21 has a rectangular longitudinal cross-section. The introduction rib 22 is a protrusion with a protrusion dimension that gradually increases toward the lower opening 18 side, extending from the edge of the upper opening 17 of the through-hole 12 to the center in the vertical direction. The longitudinal cross-section of the introduction rib 22 is a substantially right triangle with its oblique sides formed by arcs recessed toward the inner peripheral surface 19. The lower end of the introduction rib 22 and the upper end of the receiving rib 21 are continuous at the vertical center of the through hole 12.

[0051] like Figure 5 As shown, the cross-sectional shape of the positioning body 20, formed of a protrusion, perpendicular to its vertical direction is formed into a fan-shaped shape. The positioning body 20 is positioned in the through-hole 12 so that the arc of the longer side of the fan-shaped shape faces the inner peripheral surface 19. While the cross-sectional shape of the receiving rib 21 is constant in the vertical direction, the cross-sectional shape of the introduction rib 22 varies in the vertical direction. Specifically, the upper end of the cross-sectional shape of the introduction rib 22 is formed by a portion of the opening edge of the upper opening 17 of the through-hole 12 formed by the circular hole, and the protrusion gradually increases as it moves downward, with the lower end formed by the upper end of the receiving rib 21.

[0052] The protruding tip of the receiving rib 21 is formed with a receiving surface 23, a curved surface extending vertically and curving circumferentially. The protruding tip of the introduction rib 22 is formed with an introduction surface 24, a curved surface extending obliquely from the upper end of the receiving rib 21 toward the opening edge of the upper opening 17 and curving circumferentially. The cross-sectional curvatures of the receiving surface 23 and the introduction surface 24 are those of a circular arc centered at the center of the through-hole 12. The cross-sectional curvature of the receiving rib 21 (receiving surface 23) is constant in the vertical direction. Meanwhile, the cross-sectional curvature of the introduction rib 22 (introduction surface 24) gradually increases from the top to the bottom, with the top end having the same curvature as the through-hole 12 and the bottom end having the same curvature as the cross-sectional curvature of the receiving rib 21.

[0053] The solder balls 2 are arranged by first aligning the mask 1 with respect to the substrate 3 and then placing the mask 1 on the substrate 3. At this point, the lower ends of the protrusions 14 abut against the upper surface of the substrate 3, allowing the mask 1 to be stably placed on the substrate 3 with an appropriate facing distance between the lower surface of the mask body 10 and the upper surface of the substrate 3.

[0054] Next, a plurality of solder balls 2 are supplied onto the mask 1, and a scraper brush S is used to sweep the solder balls 2 over the mask 1 and disperse them, thereby dropping the solder balls 2 one by one into the through-holes 12. The solder balls 2 are about to fall into the through-holes 12 when their center of gravity is above the upper opening 17 of the through-hole 12. The solder balls 2 that have initially fallen into the through-holes 12 are guided by the introduction surfaces 24 of the introduction ribs 22 toward the center of the through-hole 12, i.e., toward the predetermined position for holding the solder balls 2, while falling into the through-hole 12. Subsequently, the solder balls 2 are guided downward by the receiving surfaces 23 of the introduction ribs 22 and dropped into the predetermined position in the through-hole 12. The solder balls 2 dropped into the through-holes 12 are firmly held and positioned at the predetermined position from three directions by the receiving ribs 21 of the three positioning bodies 20 in a three-point supported manner, and are thus temporarily fixed and bonded to the flux 7. In this state, the center of solder ball 2 is aligned with the center of through-hole 12 when viewed from above, and a gap is formed between solder ball 2 and inner peripheral surface 19 of through-hole 12, excluding the portion where positioning members 20 are formed. Finally, mask 1 is lifted vertically from substrate 3 and removed. This completes the alignment process, and solder ball 2 is placed on electrode 6.

[0055] The through hole 12 is formed by a straight hole with a constant opening diameter in the vertical direction (through direction), but the through hole 12 can also be formed by a tapered hole that is narrowed at the bottom or a tapered hole that is narrowed at the top. In short, the through hole 12 can be a through hole as long as the opening diameter D1 of the upper opening 17 is larger than the diameter d of the solder ball 2. The longitudinal cross-sectional shape of the introduction rib 22 is formed into a roughly right-angled triangle shape with the oblique side formed by an arc that is recessed toward the inner peripheral surface 19, but the longitudinal cross-sectional shape can also be formed into a roughly right-angled triangle shape with the oblique side formed by an arc that bulges toward the center of the hole. The boundary between the introduction rib 22 and the receiving rib 21 does not need to be the central part of the through hole 12 in the vertical direction. The protruding dimensions of each positioning body 20 do not need to be the same, and can also be formed so that the protruding dimensions are different.

[0056] (Second embodiment) Figure 6 The second embodiment of the mask for arranging solder balls involved in the present invention is shown. In this second embodiment, the number of positioning bodies 20 formed is different from that of the first embodiment. Four positioning bodies 20 are provided at circumferentially equally spaced positions on the inner circumferential surface 19 of the through hole 12. Two of the four positioning bodies 20 are provided at positions where an imaginary line V passing through the hole center of the through hole 12 intersects with the inner circumferential surface 19 of the through hole 12 on the upstream side of the moving direction of the scraper brush S, and at positions where the above-mentioned imaginary line V intersects with the inner circumferential surface 19 of the through hole 12 on the downstream side of the moving direction of the scraper brush S. The remaining two positioning bodies 20 are provided at positions rotated 90 degrees clockwise from the previous positioning body 20 with the hole center of the through hole 12 as a reference. The other structures are the same as those of the first embodiment, so the same figure marks are marked on the same parts and their descriptions are omitted. The same applies to the third embodiment and thereafter.

[0057] (Third embodiment) Figure 7 The third embodiment of the mask for arranging solder balls involved in the present invention is shown. In this third embodiment, the number of positioning bodies 20 formed and the circumferential length of the positioning bodies 20 are different from those in the first embodiment. Two positioning bodies 20 are arranged at equal intervals along the circumferential direction on the inner circumferential surface 19 of the through-hole 12. The two positioning bodies 20 are arranged at positions where an imaginary line V passing through the hole center of the through-hole 12 intersects with the inner circumferential surface 19 of the through-hole 12 on the upstream side of the moving direction of the scraper brush S, and at positions where the above-mentioned imaginary line V intersects with the inner circumferential surface 19 of the through-hole 12 on the downstream side of the moving direction of the scraper brush S. In addition, in this embodiment, corresponding to the reduction in the number of positioning bodies 20 formed, the circumferential formation area of ​​the positioning bodies 20 on the inner circumferential surface 19 of the through-hole 12 is made larger than that of the positioning bodies 20 of the first embodiment. In addition, the formation area of ​​the above-mentioned positioning bodies 20 is preferably set to have a center angle less than 90 degrees. This is because if the center angle of the region where the positioning body 20 is formed is 90 degrees or greater, friction caused by the contact between the solder ball 2 and the receiving surface 23 increases, and the solder ball 2 may get stuck when falling into the through hole 12 .

[0058] (Fourth embodiment) Figure 8 The fourth embodiment of the solder ball arrangement mask according to the present invention is shown. In this fourth embodiment, the number of positioning bodies 20 formed is different from that of the first embodiment. Two positioning bodies 20 are provided on the inner circumferential surface 19 of the through-hole 12, similar to the third embodiment. When the inner circumferential surface 19 of the through-hole 12 is divided into front and rear semi-circumferential surfaces 19a and 19b, the two positioning bodies 20 are arranged on the rear semi-circumferential surface 19b in a line-symmetrical manner with an imaginary line V passing through the center of the through-hole 12 as the axis of symmetry. In this embodiment, the solder ball 2 is held in a predetermined position by the two positioning bodies 20 and the inner circumferential surface 19 of the through-hole 12. When viewed from above, the center of the solder ball 2 held in the predetermined position is located at a different position from the center of the through-hole 12. The positioning bodies 20 of this embodiment are preferably configured such that the protruding size is set so that the largest inscribed circle defined by the protruding front ends of the two positioning bodies 20 and the inner circumferential surface 19 of the through-hole 12 is equal to or slightly larger than the diameter d of the solder ball 2.

[0059] (Fifth embodiment) Figure 9 The fifth embodiment of the mask for arranging solder balls involved in the present invention is shown. In this fifth embodiment, the number of positioning bodies 20 formed and the circumferential length of the positioning bodies 20 are different from those in the first embodiment. Specifically, a positioning body 20 is formed on the inner circumferential surface 19 of the through hole 12. In addition, when the inner circumferential surface 19 of the through hole 12 is divided into the front and rear semi-circumferential surfaces 19a and 19b, the positioning body 20 is arranged on the rear semi-circumferential surface 19b. The circumferential length of the positioning body 20 is larger than that of the positioning body 20 of the first embodiment. In addition, the positioning body 20 is arranged in a line symmetrical shape with an imaginary line V passing through the center of the through hole 12 as the symmetry axis. In the through hole 12, the solder ball 2 is maintained at a predetermined position by a positioning body 20 and the inner circumferential surface 19 of the through hole 12, as in the previous fourth embodiment. When viewed from above, the center of the solder ball 2 maintained at the predetermined position is located at a different position from the center of the through hole 12. In the positioning body 20 of this embodiment, for example, when the diameter d of the solder ball 2 is set to 1 and the opening diameter D1 (opening diameter D2) of the upper opening 17 (lower opening 18) is set to 1.25 (1.25 times the diameter d of the solder ball 2), the protruding dimension of the positioning body 20 is preferably set to be less than 0.25.

[0060] (Sixth embodiment) Figure 10The sixth embodiment of the solder ball arrangement mask according to the present invention is shown. In this sixth embodiment, the cross-sectional shape of the positioning body 20 differs from that of the first embodiment. Specifically, the positioning body 20, which is formed of ridges, has a trapezoidal cross-sectional shape perpendicular to its vertical direction. The positioning body 20 is arranged in the through hole 12 such that the bottom edge of the long side of the trapezoid faces the inner peripheral surface 19. A receiving surface 23, which is formed by a flat surface extending vertically, is formed at the protruding front end of the receiving rib 21. An introduction surface 24, which is formed by a flat surface extending obliquely from the upper end of the receiving rib 21 toward the opening edge of the upper opening 17, is formed at the protruding front end of the introduction rib 22.

[0061] (Seventh embodiment) Figure 11 The seventh embodiment of the mask for arranging solder balls according to the present invention is shown. In this seventh embodiment, the cross-sectional shape of the positioning body 20 is different from that of the first embodiment. Specifically, the cross-sectional shape of the positioning body 20, which is composed of protrusions, is formed into a fan-shaped shape perpendicular to the vertical direction thereof, with the main part rounded, and the positioning body 20 is arranged in the through hole 12 in such a way that the fan-shaped arc faces the inner peripheral surface 19. A receiving surface 23 composed of an arc surface extending up and down is formed at the protruding front end of the receiving rib 21, and an introduction surface 24 composed of an arc surface extending obliquely from the upper end of the receiving rib 21 toward the opening edge of the upper opening 17 is formed at the protruding front end of the introduction rib 22.

[0062] (Eighth Embodiment) Figure 12 The eighth embodiment of the solder ball arrangement mask according to the present invention is shown. In this eighth embodiment, the cross-sectional shape of the positioning body 20 differs from that of the first embodiment. Specifically, the positioning body 20, formed of projections, has a fan-shaped cross-sectional shape perpendicular to its vertical direction. The positioning body 20 is positioned within the through-hole 12 such that the fan-shaped arc faces the inner circumferential surface 19. A receiving edge 30, formed by a ridgeline extending in the vertical direction, is formed at the protruding tip of the receiving rib 21. An introduction edge 31, formed by a ridgeline extending at an angle relative to the vertical direction, is formed at the protruding tip of the introduction rib 22. A solder ball 2 dropped into the through-hole 12 is guided to a predetermined position by the introduction edge 31 and held and positioned there by the receiving edge 30. As a variation of this embodiment, two introduction edges 31, 31, may be formed at the protruding tips of the receiving rib 21 and the introduction rib 22. In this case, the cross-sectional shape perpendicular to the vertical direction of the positioning body 20, formed of projections, can be modified.

[0063] (Ninth embodiment) Figure 13The ninth embodiment of the mask for arranging solder balls involved in the present invention is shown. In this ninth embodiment, the longitudinal cross-sectional shape of the positioning body 20 is different from that of the first embodiment. The receiving rib 21 is composed of a protrusion with a constant protruding size, which is formed from the opening edge of the lower opening 18 of the through-hole 12 to the center in the vertical direction. The longitudinal cross-sectional shape of the receiving rib 21 is formed into a rectangular shape. The introduction rib 22 is composed of a protrusion formed in a manner that the protruding size gradually increases toward the lower opening 18 side, which is formed from the opening edge of the upper opening 17 of the through-hole 12 to the center in the vertical direction. The longitudinal cross-sectional shape of the introduction rib 22 is formed into a right triangle shape. The lower end of the introduction rib 22 of the two ribs 21 and 22 is continuous with the upper end of the receiving rib 21 in the center of the through-hole 12 in the vertical direction.

[0064] (Tenth embodiment) Figure 14 The following figure shows a tenth embodiment of the solder ball arrangement mask according to the present invention. In this tenth embodiment, the longitudinal cross-sectional shape of the positioning body 20 differs from that of the first embodiment. Positioning body 20, formed of ridges, comprises a receiving portion 21 and an introduction rib (introduction portion) 22. The receiving portion 21 is provided at the edge of the lower opening 18 of the through-hole 12 to receive and retain the solder ball 2 within the through-hole 12. The introduction rib 22 is provided from the upper opening 17 to the lower opening 18 of the through-hole 12 to guide the solder ball 2 to a predetermined position within the through-hole 12. The receiving portion 21 is formed by the lower end of the introduction rib 22. The introduction rib 22 comprises a first rib 34 provided on the upper opening 17 side and a second rib 35 provided on the lower opening 18 side.

[0065] First rib 34 extends from the edge of upper opening 17 of through-hole 12 to its vertical center. Its longitudinal cross-section is a roughly right-angled triangle, with the hypotenuse formed by an arc recessed toward inner peripheral surface 19. Second rib 35 extends from the vertical center of through-hole 12 to the edge of lower opening 18. Its longitudinal cross-section is a trapezoidal shape with one leg formed by a vertical side. The lower end of first rib 34 and the upper end of second rib 35 of these two ribs (first rib 34 and second rib 35) are continuous at the vertical center of through-hole 12. In this embodiment, receiving surface 23 is omitted; solder ball 2 is received by the protruding tip of receiving portion 21 and held in place.

[0066] (Eleventh embodiment) Figure 15The eleventh embodiment of the solder ball alignment mask according to the present invention is shown. In this embodiment, the longitudinal cross-sectional shape of the first rib 34 differs from that of the tenth embodiment. First rib 34 extends from the edge of the upper opening 17 of through-hole 12 to the vertical center, forming a right-angled triangle in longitudinal cross-section. The inclination angle of the introduction surface 24 (introduction edge 31) relative to the vertical line (inner circumferential surface 19 of through-hole 12) is formed such that the first rib 34 has a relatively small inclination angle, while the second rib 35 has a relatively large inclination angle. The lower ends of the first rib 34 and the upper ends of the second rib 35 of these two ribs (first rib 34 and second rib 35) are continuous at the vertical center of through-hole 12.

[0067] (Twelfth embodiment) Figure 16 The twelfth embodiment of the solder ball arrangement mask according to the present invention is shown. In this twelfth embodiment, the longitudinal cross-sectional shape of the positioning body 20 differs from that of the first embodiment. The positioning body 20, formed of ridges, comprises a receiving portion 21 and an introduction rib (introduction portion) 22. The receiving portion 21 is provided at the opening edge of the lower opening 18 of the through-hole 12 to receive and retain the solder ball 2 within the through-hole 12, while the introduction rib 22 extends from the upper opening 17 to the lower opening 18 of the through-hole 12 to guide the solder ball 2 to a predetermined position within the through-hole 12. The longitudinal cross-sectional shape of the introduction rib 22 is formed into a roughly right triangle shape, with the hypotenuse formed by an arc recessed toward the inner peripheral surface 19. The receiving portion 21 is formed by the lower end of the introduction rib 22, and the receiving surface 23 is omitted. The solder ball 2 is received by the protruding front end of the receiving portion 21 and retained in the predetermined position.

[0068] (Thirteenth embodiment) Figure 17 The thirteenth embodiment of the solder ball arraying mask according to the present invention is shown. In this thirteenth embodiment, the longitudinal cross-sectional shape of the guide rib 22 differs from that of the twelfth embodiment. The longitudinal cross-sectional shape of the guide rib 22 is formed into a right-angled triangle. The receiving portion 21 is formed by the lower end of the guide rib 22, and the receiving surface 23 is omitted. The solder ball 2 is received by the protruding tip of the receiving portion 21 and held in a predetermined position.

[0069] (Fourteenth embodiment) Figure 18 The fourteenth embodiment of the solder ball arrangement mask according to the present invention is shown. In this fourteenth embodiment, the longitudinal cross-sectional shape of the positioning body 20 differs from that of the first embodiment. Positioning body 20, formed of protruding ribs, comprises a receiving rib 21, an introduction rib 22, and a stepped portion 38. The receiving rib 21 is positioned on the lower opening 18 side of the through-hole 12 to receive and retain the solder ball 2 within the through-hole 12. The introduction rib 22 is positioned on the upper opening 17 side of the through-hole 12 to guide the solder ball 2 to a predetermined position within the through-hole 12. The stepped portion 38 is positioned between the lower end of the introduction rib 22 and the upper end of the receiving rib 21.

[0070] The receiving rib 21 is composed of a protrusion with a constant protruding dimension, and is formed from the opening edge of the lower opening 18 of the through-hole 12 to the center in the vertical direction. The longitudinal cross-sectional shape of the receiving rib 21 is formed into a rectangular shape. The introduction rib 22 is composed of a protrusion formed in a manner that the protruding dimension gradually increases toward the lower opening 18 side, and is formed from the opening edge of the upper opening 17 of the through-hole 12 to the center in the vertical direction. The longitudinal cross-sectional shape of the introduction rib 22 is formed into a right-angled triangle shape. The two ribs 21 and 22 are formed so that the protruding dimension of the receiving rib 21 is relatively small and the protruding dimension of the introduction rib 22 is relatively large. A step portion 38 is formed between the two ribs 21 and 22, and the lower end of the introduction rib 22 and the upper end of the receiving rib 21 are continuous in the center of the through-hole 12 in the vertical direction via the step portion 38.

[0071] (Fifteenth embodiment) Figure 19 The fifteenth embodiment of the solder ball arraying mask according to the present invention is shown. In this fifteenth embodiment, the longitudinal cross-sectional shape of the guide rib 22 differs from that of the fourteenth embodiment. The guide rib 22 has a rectangular longitudinal cross-sectional shape. The upper end of the guide rib 22 protrudes from the edge of the upper opening 17 toward the center of the through hole 12.

[0072] In addition to the above, the positioning bodies 20 can be configured in various shapes by combining the number and position of the positioning bodies 20 shown in the first to fifth embodiments, the cross-sectional plane shapes shown in the sixth to eighth embodiments, and the longitudinal cross-sectional shapes shown in the ninth to fifteenth embodiments. When multiple positioning bodies 20 are provided, it is not necessary to provide positioning bodies 20 of the same shape; positioning bodies 20 of different shapes can also be provided on the inner circumferential surface 19 of the through hole 12. The positioning bodies 20 do not need to be arranged in a line-symmetrical shape with respect to the imaginary line V.

[0073] As described above, in the mask 1 according to each of the above-described embodiments, the solder ball 2 is guided and held at a predetermined position within the through-hole 12 by one or more positioning members 20 extending from the inner circumferential surface 19 of the through-hole 12. Therefore, compared to conventional masks that hold the solder ball within the inner circumferential surface of the through-hole, the opening diameter D1 of the upper opening 17 of the through-hole 12 can be made larger than the diameter d of the solder ball 2 by the extension of the positioning members 20. This increases the chance that the center of gravity of the solder ball 2 swept by the squeegee brush S will be located above the upper opening 17 of the through-hole 12, thereby facilitating the introduction of the solder ball 2 into the through-hole 12. Furthermore, since the opening diameter D1 of the upper opening 17 of the through-hole 12 is made larger than the diameter d of the solder ball 2, a gap is formed between the circumference of the solder ball 2 that has fallen into the through-hole 12 and the inner circumferential surface 19 of the through-hole 12, thereby preventing the solder ball 2 that has fallen into the through-hole 12 from contacting the inner circumferential surface 19 and becoming stuck. As described above, according to the mask 1 according to each of the above-described embodiments, the solder balls 2 can be dropped into the through-holes 12 more quickly and smoothly than with conventional masks.

[0074] Positioning body 20, formed of protruding ridges extending vertically along inner circumferential surface 19 of through-hole 12, includes a receiving portion (receiving rib) 21 and an introduction portion (introduction rib) 22. Receiving portion (receiving rib) 21 is located on the lower opening 18 side of through-hole 12 to receive and hold solder ball 2 within through-hole 12, while introduction portion (introduction rib) 22 is located on the upper opening 17 side of through-hole 12 to guide solder ball 2 to a predetermined position within through-hole 12. Consequently, solder ball 2, which falls into through-hole 12 from upper opening 17, is appropriately guided toward the predetermined position by introduction portion 22, while receiving portion 21 reliably holds and positions the guided solder ball 2. Consequently, solder ball 2 can be accurately placed on substrate 3 at a predetermined position (the center of electrode 6 when viewed from above).

[0075] Since the protruding dimension of introduction portion 22 gradually increases toward lower opening 18, solder ball 2 can be guided gradually toward a predetermined position, thereby smoothly being introduced into receiving portion 21. Furthermore, since the upper end of introduction portion 22 is formed by a portion of the opening edge of upper opening 17 of through-hole 12, which is a circular hole, introduction portion 22 can guide solder ball 2 from the initial stage of its entry into through-hole 12, thereby more smoothly introducing solder ball 2 into receiving portion 21.

[0076] Three or more positioning bodies 20 are provided on the inner circumferential surface 19 of the through hole 12. When the inner circumferential surface 19 of the through hole 12 is divided into two half-circumferential surfaces 19a and 19b at any position, a positioning body 20 is provided on each half-circumferential surface 19a or 19b. Thus, the positioning bodies 20 can hold the solder ball 2 in a three-point supported configuration, thereby positioning the solder ball 2 at a predetermined position within the through hole 12. This allows the solder ball 2 to be accurately mounted at an appropriate position on the substrate 3.

[0077] Since the positioning bodies 20 are arranged at equal intervals in the circumferential direction of the inner peripheral surface 19 of the through hole 12 , the positioning bodies 20 can evenly support and position the solder ball 2 at three points around it, thereby allowing the solder ball 2 to be mounted at an appropriate position on the substrate 3 with higher precision.

[0078] Since the positioning body 20 is arranged on the inner peripheral surface 19 of the through hole 12, the through hole 12 is located on the downstream side of the moving direction of the scraper brush S used to move on the arrangement mask to make the solder ball 2 fall into the through hole 12. Therefore, the positioning body 20 can be used to receive the solder ball 2 that is swept to the downstream side of the moving direction of the scraper brush S and introduced into the upstream half of the upper opening 17 of the through hole 12 and falls into the through hole 12, so that the positioning body 20 can be used to reliably guide the solder ball 2 to the predetermined position.

[0079] When viewed from above, when an imaginary line V is assumed to pass through the center of the through hole 12, a positioning body 20 is provided at a position where the imaginary line V pointing in the moving direction of the scraper brush S intersects with the inner peripheral surface 19 of the through hole 12 on the downstream side of the moving direction of the scraper brush S. Therefore, the solder ball 2 that is introduced into the upstream half of the upper opening 17 of the through hole 12 and falls into the through hole 12 can be reliably received.

[0080] Since the cross-sectional shape of the positioning body 20 composed of protrusions that is perpendicular to the up and down directions is formed into a fan-shaped shape, and the positioning body 20 is set in such a way that the arc of the longer side of the fan-shaped shape faces the inner peripheral surface 19 of the through hole 12, the solder ball 2 can be guided and held by the concave arc surface, thereby preventing damage to the solder ball 2 caused by contact with the positioning body 20.

[0081] Since the cross-sectional shape of the positioning body 20, which is composed of projections, is formed into a trapezoidal shape in a vertical direction, and the positioning body 20 is arranged so that the base of the longer side of the trapezoid faces the inner peripheral surface 19 of the through-hole 12, the solder ball 2 can be guided and held by the flat surface, thereby preventing damage to the solder ball 2 caused by contact with the positioning body 20. In addition, the solder ball 2 can be brought into point contact with the positioning body 20, thereby preventing the solder ball 2 that falls into the through-hole 12 from being caught on the positioning body 20.

[0082] Since the cross-sectional shape of the positioning body 20, which is formed of a protrusion and is perpendicular to the vertical direction, is formed into a sector-shaped shape with a rounded main portion, and the positioning body 20 is arranged so that the sector-shaped arc surface faces the inner peripheral surface 19 of the through-hole 12, the arc surface (arc shape) of the protrusion can guide and retain the solder ball 2, thereby preventing damage to the solder ball 2 caused by contact with the positioning body 20. In addition, the solder ball 2 can be brought into point contact with the positioning body 20, thereby preventing the solder ball 2 that has fallen into the through-hole 12 from being caught on the positioning body 20.

[0083] Since the cross-sectional shape of the positioning body 20 composed of the protrusions is formed into a fan-shaped shape at right angles to the up and down directions, and the positioning body 20 is arranged in such a way that the fan-shaped arc surface faces the inner peripheral surface 19 of the through hole 12, the solder ball 2 can be made into point contact with the positioning body 20, thereby preventing the solder ball 2 that falls into the through hole 12 from getting stuck on the positioning body 20.

[0084] The array mask according to the present invention can contribute to Goal 9 (Building a foundation for industrial and technological innovation) and Goal 12 (Responsible production and consumption) of the Sustainable Development Goals (SDGs) promoted by the United Nations.

[0085] While the above embodiments describe an alignment mask 1 for inserting a conductive object, such as a solder ball 2, into a through-hole 12 formed of a circular hole, examples of alignment masks include an alignment mask in which the through-holes are polygonal or rounded polygonal holes, or an alignment mask in which a conductive object, such as a columnar (or cylindrical) conductive pillar, is inserted into the through-holes. These alignment masks may also include one or more positioning members extending from the inner circumference of the through-holes toward the center of the holes to hold and position the conductive object (solder ball, conductive pillar) in a predetermined position.

Claims

1. An arrangement mask for placing solder balls (2) in through holes (12) corresponding to a predetermined arrangement pattern, thereby placing solder balls (2) at predetermined positions on a substrate (3), wherein the arrangement mask is characterized in that: On the inner peripheral surface (19) of a through hole (12) consisting of a circular hole whose opening diameter (D1) of an upper opening (17) is larger than the diameter (d) of a solder ball (2), one or more positioning bodies (20) are formed extending toward the center of the hole. The positioning bodies (20) are used to guide the solder ball (2) inserted into the through hole (12) toward a predetermined position, and to hold and position the solder ball (2) at the predetermined position.

2. The array mask according to claim 1, wherein The positioning body (20) is composed of a protrusion extending in the upper and lower directions along the inner peripheral surface (19) of the through hole (12), and is composed of a receiving portion (21) and an introduction portion (22), wherein the receiving portion (21) is arranged on the side of the lower opening (18) of the through hole (12) to receive and hold the solder ball (2) in the through hole (12), and the introduction portion (22) is arranged on the side of the upper opening (17) of the through hole (12) to guide the solder ball (2) to a predetermined position in the through hole (12).

3. The mask for alignment according to claim 2, wherein The introduction portion (22) is formed so that the protruding size gradually increases toward the lower opening (18). The upper end of the introduction portion (22) is formed by a portion of the opening edge of the upper opening (17) of the through hole (12), and the through hole (12) is formed by a circular hole.

4. The array mask according to claim 1, wherein Three or more positioning bodies (20) are provided on the inner peripheral surface (19) of the through hole (12). When the inner circumferential surface (19) of the through hole (12) is divided into two half circumferential surfaces (19a, 19b) at an arbitrary position, a positioning body (20) is provided on either half circumferential surface (19a, 19b).

5. The array mask according to claim 4, wherein The positioning bodies (20) are arranged at equal intervals in the circumferential direction of the inner peripheral surface (19) of the through hole (12).

6. The alignment mask according to claim 1, wherein The positioning body (20) is provided on the inner peripheral surface (19) of the through hole (12), and the through hole (12) is located on the downstream side of the moving direction of the scanning tool (S) for moving on the array mask to make the solder ball (2) fall into the through hole (12).

7. The alignment mask according to claim 6, wherein When looking down, assuming an imaginary line (V) passing through the hole center of the through hole (12), A positioning body (20) is provided at a position where an imaginary line (V) pointing in the moving direction of the sweeping tool (S) intersects with an inner peripheral surface (19) of the through hole (12) on the downstream side of the moving direction of the sweeping tool (S).

8. The array mask according to claim 2, wherein: The cross-sectional shape of the positioning body (20) formed by the protrusions perpendicular to the up-down direction is formed into a fan-shaped shape, and the positioning body (20) is arranged in a manner such that the arc of the longer side of the fan-shaped shape faces the inner peripheral surface (19) of the through hole (12).

9. The array mask according to claim 2, wherein: The cross-sectional shape of the positioning body (20) formed by the protrusions is formed into a trapezoidal shape perpendicular to the up-down direction, and the positioning body (20) is arranged in a manner such that the bottom side of the long side of the trapezoid faces the inner peripheral surface (19) of the through hole (12).

10. The array mask according to claim 2, wherein The cross-sectional shape of the positioning body (20) formed by the protrusions, which is perpendicular to the up-down direction, is formed into a fan-shaped shape with a main part rounded, and the positioning body (20) is arranged in a manner such that the fan-shaped arc faces the inner peripheral surface (19) of the through hole (12).

11. The array mask according to claim 2, wherein The cross-sectional shape of the positioning body (20) formed by the protrusions is formed into a fan-shaped shape perpendicular to the up-down direction, and the positioning body (20) is arranged in a manner such that the fan-shaped arc faces the inner peripheral surface (19) of the through hole (12).

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