Solder bump forming materials

Abstract

To provide a member for solder bump formation capable of preventing a contact of a solder ball and a substrate part in the case of rolling or sheeting.SOLUTION: A member 1A, 1B for solder bump formation is a member for solder bump formation forming a rolled or sheeted multilayer structure and comprises a substrate 2 including a first face 2a and a second face 2b at an opposite side of the first face 2a. An array region R, in which a plurality of solder balls S held by the substrate part 2 is arrayed, and a spacer 4 are provided in the substrate part 2 at the side of the first face 2a of the substrate 2. A height position of a top 4a of the spacer 4 in the substrate 2 is higher than a height position of a top Sa of the solder balls S in the substrate part 2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a solder bump forming member. [Background technology]

[0002] Flip-chip mounting is known as one of the techniques for high-density mounting of electronic components. In flip-chip mounting, for example, solder bumps are formed in advance on electrodes provided on one circuit member, and the electrodes of one circuit member and the electrodes of the other circuit member are joined by melting the solder bumps. This results in a connection structure between the circuit members.

[0003] One example of a technique for forming solder bumps on electrodes is the solder bump formation method described in Patent Document 1. This conventional solder bump formation method uses a positioning plate with multiple recesses formed therein corresponding to the spacing between electrodes on a substrate. This positioning plate is used as a solder bump formation member for the electrodes, and solder balls are placed in each recess of the positioning plate. A transfer roll with an adhesive outer surface is rolled over the surface of the positioning plate, transferring the solder balls to the adhesive surface of the transfer roll. Then, the transfer roll is rolled over electrodes of the substrate provided with an adhesive material, transferring the solder balls from the adhesive surface of the transfer roll to the electrodes of the substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-157626 Summary of the Invention [Problem to be solved by the invention]

[0005] In actual electronic component mounting situations, it is expected that the solder bump forming member described above will be transported and stored in rolls or sheets. However, in a configuration in which the solder balls protrude from recesses, such as the positioning plate described in Patent Document 1 (see FIG. 2(b) of Patent Document 1), when the solder bump forming member is rolled or sheeted, there is a risk that the protruding portions of the solder balls may come into contact with the underlying base of the solder bump forming member. In this case, the shape of the solder balls may be distorted, potentially affecting reliability during electronic component mounting. Furthermore, contact of the solder balls with the base may result in the solder balls coming loose due to static electricity or poor transfer due to the adhesion of organic matter to the solder balls.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a member for forming solder bumps that can prevent contact between the solder balls and the base portion when formed into a roll or sheet. [Means for solving the problem]

[0007] A solder bump forming member according to one aspect of the present disclosure is a solder bump forming member having a roll-shaped or sheet-shaped laminated structure, and includes a base portion having a first surface and a second surface opposite the first surface, and on the first surface side of the base portion, an arrangement area in which a plurality of solder balls held on the first surface are arranged, and a spacer is provided, and the height position of the top of the spacer from the base portion is higher than the height position of the top of the solder ball from the base portion.

[0008] In this solder bump forming member, a spacer is provided on the first surface of the base portion so that it is higher than the height of the top of the solder ball. The placement of this spacer allows a certain amount of space to be formed between the solder ball held on the base portion and the base portion of the solder bump forming member that overlaps it. Therefore, even when the solder bump forming member is formed into a roll or sheet, contact between the solder ball and the base portion can be prevented. Preventing contact between the solder ball and the base portion effectively prevents problems such as solder ball dislodgment due to static electricity and transfer failure due to adhesion of organic matter to the solder ball.

[0009] If the thickness of the base from the second surface to the first surface is H1, the height of the spacer is H2, and the average particle size of the solder balls is H3, (H1 + H2) may be greater than 1 and less than 600 times H3. This allows the spacer to form a sufficient space relative to the size of the solder balls. Therefore, contact between the solder balls and the base can be suitably prevented. Furthermore, the height of the space is not excessive, allowing for miniaturization of the solder bump forming member.

[0010] If the average particle size of the solder balls is H3 and the difference in height between the top of the spacer and the top of the solder ball is H4, H4 may be 0.5 times or more of H3. This allows the spacer to form a sufficient space relative to the size of the solder balls. Therefore, contact between the solder balls and the base can be effectively prevented.

[0011] If the thickness of the base from the second surface to the first surface is H1 and the difference in height between the top of the spacer and the top of the solder ball is H4, H1 may be greater than 1 / 10 of H4. In this case, the base has a constant thickness, which ensures sufficient handleability of the base.

[0012] The arrangement region may be provided with a plurality of recesses for holding the respective solder balls. In this case, the solder balls are positioned by the recesses, thereby ensuring reliable transfer of the solder balls.

[0013] If the difference in height between the top of the spacer and the top of the solder ball is H4 and the thickness of the base portion at the recess is H5, H4 may be 1 / 50 or more and 10 times or less of H5. This allows the spacer to form a sufficient space relative to the size of the solder ball. Therefore, contact between the solder ball and the base portion can be suitably prevented. Furthermore, the height of the space is not excessive, allowing for miniaturization of the solder bump forming member.

[0014] If the thickness of the base at the recess is H5 and the amount of protrusion of the solder ball from the recess is H6, H5 may be at least twice H6. In this case, the depth of the recess is sufficient for the amount of protrusion of the solder ball, and the occurrence of the solder ball falling out of the recess can be suppressed.

[0015] The spacer may be bonded to the first surface of the base and not bonded to the second surface of the adjacent base in the laminated structure. This configuration prevents the spacer from shifting relative to the base. Furthermore, when transferring the solder balls, the spacer can be prevented from becoming waste separate from the base.

[0016] The spacer may be bonded to the second surface of the base and not bonded to the first surface of the adjacent base in the laminated structure. This configuration prevents the spacer from interfering with the arrangement area when the spacer is arranged. Furthermore, when the solder balls are transferred, the spacer is prevented from becoming waste separate from the base.

[0017] The spacer may be unbonded to the first surface of one adjacent base portion and the second surface of the other adjacent base portion in the laminated structure. In this case, the spacer can be easily removed. Therefore, the problem of the spacer interfering with the transfer device during solder ball transfer can be prevented. In addition, it becomes easier to transfer solder balls to an area larger than the arrangement area.

[0018] A cover film may be provided between the spacer and the second surface of the adjacent base portion in the laminate structure, spaced apart from the solder balls. In this case, the cover film maintains the space defined by the spacer. This more reliably prevents contact between the solder balls and the base portion.

[0019] The spacer may be bonded to the first surface of the base, and the cover film may be unbonded to the spacer and the spacer of the adjacent base in the laminate structure. In this case, the cover film is independent of the base and the spacer, making it easier to remove the cover film and also broadening the range of materials that can be selected for the cover film.

[0020] The spacers may be unbonded to adjacent base portions in the laminated structure, and the cover films may be bonded to the spacers. In this case, the cover films can be easily removed together with the spacers. By removing the spacers and cover films when transferring the solder balls, problems such as the spacers and cover films interfering with the transfer device can be prevented.

[0021] The laminated structure may be in a roll shape, with the arrangement region being continuously provided in the widthwise central portion of the first surface side of the base in the extending direction of the base, and the spacers being continuously provided in the extending direction of the base so as to sandwich the arrangement region in the widthwise direction. In this case, the roll-shaped solder bump forming member can be easily produced by, for example, winding the base together with the spacers using a roll-to-roll method. Furthermore, the symmetry of the arrangement of the spacers relative to the arrangement region allows the solder bump forming member to be wound and unwound uniformly while maintaining the shape retention of the space provided by the spacers.

[0022] The laminated structure is in a roll shape, and the array region is provided in a central portion in the width direction of the first surface side of the base at a predetermined interval in the extending direction of the base, and the spacers may be provided continuously in the extending direction of the base so as to sandwich the array region in the width direction. In this case, the bump-forming member can be easily produced, for example, by a roll-to-roll method. Furthermore, the symmetry of the arrangement of the spacers relative to the array region allows the bump-forming member to be wound and unwound uniformly while maintaining the shape retention of the space provided by the spacers.

[0023] The laminated structure may be in the form of a sheet, the arrangement region may be provided in the central portion of the first surface side of the base portion, and the spacers may be provided so as to surround the arrangement region. In this case, the symmetry of the arrangement of the spacers relative to the arrangement region can favorably maintain the shape of the space provided by the spacers. [Effects of the Invention]

[0024] According to the present disclosure, contact between the solder balls and the base portion can be prevented when the solder balls are rolled or sheeted. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a schematic perspective view showing a solder bump formation member according to a first embodiment of the present disclosure. [Figure 2] 2 is a schematic cross-sectional view showing a layered structure of the solder bump formation member shown in FIG. 1. FIG. [Figure 3] 10 is a schematic cross-sectional view showing the relationship between the height position of the top of a spacer and the height position of the top of a solder ball. FIG. [Figure 4] FIG. 2 is a schematic exploded cross-sectional view showing an example of the configuration of a spacer. [Figure 5] FIG. 10 is a schematic exploded cross-sectional view showing another example of the configuration of the spacer. [Figure 6] FIG. 10 is a schematic exploded cross-sectional view showing yet another example of the configuration of the spacer. [Figure 7] FIG. 10 is a schematic cross-sectional view showing a laminated structure of a solder bump forming member when a cover film is disposed. [Figure 8] FIG. 2 is a schematic exploded cross-sectional view showing an example of the configuration of a cover film. [Figure 9] FIG. 10 is a schematic exploded cross-sectional view showing another example of the configuration of the cover film. [Figure 10] FIG. 10 is a schematic plan view showing another example of the arrangement of spacers. [Figure 11] 10(a) and 10(b) are schematic plan views showing other examples of the arrangement of solder balls and spacers. [Figure 12] 10(a) and 10(b) are schematic plan views showing yet another example of the arrangement of solder ball arrangement regions and spacers. [Figure 13] FIG. 4 is a schematic perspective view showing a solder bump formation member according to a second embodiment of the present disclosure. [Figure 14] 10(a) and 10(b) are schematic plan views showing other examples of the arrangement of solder balls and spacers. [Figure 15] 10A and 10B are schematic cross-sectional views showing the relationship between the height positions of the tops of spacers and the height positions of the tops of solder balls in a modified example of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, a preferred embodiment of a member for forming a solder bump according to one aspect of the present disclosure will be described in detail with reference to the drawings.

[0027] In this specification, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. The upper or lower limit of a numerical range described in stages in this specification may be replaced with the upper or lower limit of a numerical range of another stage. [First embodiment]

[0028] FIG. 1 is a schematic perspective view showing a solder bump forming member according to a first embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view showing the layered structure of the solder bump forming member shown in FIG. 1. The solder bump forming member 1A shown in FIGS. 1 and 2 is a member used, for example, for forming solder bumps (transferring solder balls S) on electrodes of a circuit component. In the example of FIGS. 1 and 2, the solder bump forming member 1A has a rolled layered structure, and is stored, transported, and used in this state. When the solder bump forming member 1A and a solder bump forming member 1B described below are housed in a container, the container may be purged with an inert gas such as nitrogen.

[0029] The solder bump forming member 1A has a long base portion 2. The base portion 2 is strip-shaped with a predetermined width in a plan view. As shown in FIGS. 1 and 2, the base portion 2 has a first surface 2a and a second surface 2b opposite the first surface 2a. In the solder bump forming member 1A, the base portion 2 is wound into a roll with the first surface 2a facing toward the center (see FIG. 1).

[0030] Examples of materials that can be used to form the base 2 include inorganic materials such as silicon, various ceramics, glass, and stainless steel, and organic materials such as various resins. The material that can be used to form the base 2 may be a material that is highly light-transmitting. Examples of such materials include polyethylene terephthalate, transparent (colorless) polyimide, and polyamide. The material that can be used to form the base 2 may be a heat-resistant material that does not change at the melting point of the solder balls S. The material that can be used to form the base 2 may be a material that does not change when alloyed or reacted with the material that forms the solder balls S.

[0031] The base 2 may be made of a flexible film material. Examples of such materials include polyethylene terephthalate, polyethylene naphthalate, vinyl chloride resin, polystyrene, polyethylene polyphenylene sulfide, and polycarbonate. To improve the handleability of the base 2, increasing the thickness of the aforementioned materials can suppress deformation.

[0032] From the viewpoint of improving the transfer accuracy of the solder balls S to the electrodes, engineering plastics, super engineering plastics, materials obtained by compounding the above-mentioned general-purpose plastics with fillers or fibers, and inorganic materials can be used as the constituent material of the base portion 2. In this case, for example, polyamide, polyacetal, polycarbonate, polyphenylene sulfide, polyimide, polyethylene ether imide, polyamide imide, polysulfone, polyether ether ketone, etc. can be used.

[0033] An array region R in which solder balls S are held is provided on the first surface 2a side of the base portion 2. In the example of Figs. 1 and 2, the array region R is provided continuously with a constant width in the extension direction of the base portion 2, in the central portion in the width direction on the first surface 2a side of the base portion 2. A plurality of recesses 3 for holding the solder balls S are provided in the array region R. In the example of Figs. 1 and 2, the plurality of recesses 3 are arranged in a lattice pattern of 6 columns x n rows (n is an integer) in the array region R, and one solder ball S is held in each recess 3.

[0034] The recesses 3 can be formed by known methods such as imprinting, photolithography, mechanical processing, and laser processing. In particular, when using nanoimprinting, the recesses 3 can be formed with high accuracy in a relatively short process by pressing a desired mold. By providing such recesses 3, the solder balls S are positioned by the recesses 3, ensuring reliable transfer of the solder balls S.

[0035] The size (width, volume, depth, etc.) of the recesses 3 is set appropriately according to the size of the solder balls S. Here, the depth of the recesses 3 is smaller than the diameter of the solder balls S. Therefore, the top Sa side of the solder balls S held in each recess 3 protrudes from the opening surface 3a of the recess 3, as shown in FIG. 2. From the viewpoint of ensuring reliable contact between the electrodes and the solder balls S when transferring the solder balls S to the electrodes, when the depth of the recess 3 is 1, the height of the solder balls S may be 1.02 or more, or 1.07 or more.

[0036] From the viewpoint of preventing the solder balls S from falling off from the recesses 3 in situations other than when transferring to the electrodes, the height of the solder balls S may be 3.00 or less when the depth of the recesses 3 is 1. When designing the depth of the recesses 3, the average particle size of the multiple solder balls S may be regarded as the diameter of the solder balls S.

[0037] In the examples of Figures 1 and 2, the planar shape of the recess 3 is square for the solder ball S, which is circular in plan view. The planar shape of the recess 3 may be various shapes such as a square, an ellipse, a triangle, a rectangle, or other rectangular shapes, or a polygon. In the examples of Figures 1 and 2, the cross-sectional shape of the recess 3 is rectangular. The cross-sectional shape of the recess 3 may be tapered so that the opening area increases from the bottom surface 3b side toward the opening surface 3a side. The bottom surface 3b of the recess 3 is not limited to a flat surface, and may be, for example, a concave curved surface.

[0038] The solder balls S contain, for example, tin or a tin alloy. Examples of tin alloys include In-Sn alloys, In-Sn-Ag alloys, Sn-Au alloys, Sn-Bi alloys, Sn-Bi-Ag alloys, Sn-Ag alloys, Sn-Ag alloys, Sn-Ag-Cu alloys, and Sn-Cu alloys. The solder balls S may contain indium or an indium alloy. Examples of indium alloys include In-Bi alloys and In-Ag alloys.

[0039] The solder balls S may contain one or more elements selected from Ag, Cu, Ni, Bi, Zn, Pd, Pb, Au, Sb, Ge, Mn, Co, Si, Al, P, and B. The solder balls S may contain Ag or Cu from the above-mentioned elements in order to obtain good electrical conductivity reliability. By including Ag or Cu in the solder balls S, the melting point of the solder balls S can be lowered to approximately 220°C, and the bonding strength with the electrodes can be improved. The solder balls S may be particles having a metal film on the surface of resin particles. The solder balls S may consist of a single metal particle or multiple metal particles.

[0040] The average particle size of the solder balls S is, for example, 1 μm or more and 35 μm or less. The average particle size of the solder balls S may be 25 μm or less, 20 μm or less, or 15 μm or less. The average particle size of the solder balls S may be, for example, 1 μm or more, 2 μm or more, 3 μm or more, or 5 μm or more. The average particle size of the solder balls S can be measured using various methods suited to the size. Measurement methods include, for example, dynamic light scattering, laser diffraction, centrifugal sedimentation, electrical sensing zone method, and resonance mass measurement method.

[0041] Another method for measuring the average particle size of the solder balls S is to measure the particle size based on images obtained by an optical microscope or an electron microscope. Specific devices include a flow particle image analyzer, a Microtrac, and a Coulter counter. The average particle size of the solder balls S can be calculated based on the diameter of a circle equivalent to the projected area (the diameter of a circle having an area equal to the projected area of ​​the particle) when the solder balls S are observed from a direction perpendicular to the first surface 2a of the solder bump forming member 1A.

[0042] The CV value of the solder balls S is a value calculated by dividing the standard deviation of the particle diameters measured by the above-mentioned method by the average particle diameter and multiplying the result by 100. The CV value of the solder balls S may be 20% or less from the viewpoint of achieving better conductive reliability and insulating reliability. The CV value of the solder balls S may be 10% or less, or may be 7% or less. The lower limit of the CV value of the solder balls S is not particularly limited. The CV value of the solder balls S may be 1% or more, or may be 2% or more.

[0043] The solder balls S held in the recesses 3 may be in contact with the bottom surface 3b or the inner wall surface 3c of the recesses 3. Part of the solder balls S may be flat at the contact portion with the bottom surface 3b or the inner wall surface 3c. By having the solder balls S in contact with the bottom surface 3b or the inner wall surface 3c of the recesses 3, it is possible to prevent the solder balls S from falling off from the recesses 3 in situations other than when transferring to the electrodes.

[0044] An alignment mark (not shown) may be provided on the first surface 2a of the base part 2. The alignment mark may be formed, for example, by providing a concave-convex shape on the first surface 2a of the base part 2, printing with ink or pigment, printing with an inorganic material by plating or sputtering, or by laser burning. In plan view, the alignment mark may have, for example, a circle, double circle, multiple circles, triangle, rectangle, polygon, or any of these multiple angles. The alignment mark may be made of a magnetic material or a material that absorbs, reflects, or diffracts electromagnetic waves. In this case, the shape of the alignment mark is not particularly limited.

[0045] By detecting the alignment marks with an imaging device such as a camera, it becomes easier to align the electrodes to be formed with the solder balls S in the recesses 3 when forming the solder bumps. This improves the transfer accuracy of the solder balls S to the electrodes. It is sufficient to provide one or more alignment marks on the first surface 2a, but providing multiple alignment marks further improves the alignment accuracy. For example, if the base portion 2 is transparent, an additional alignment mark may be provided on the second surface 2b.

[0046] 1 and 2, a spacer 4 is provided on the first surface 2a side of the base portion 2. The spacer 4 is a member that forms a certain space V between the solder balls S held on the base portion 2 and the base portion 2 that overlaps it in the roll-shaped laminated structure (see FIG. 2). The formation of the space V makes it possible to prevent the solder balls S held in the recesses 3 from coming into contact with the second surfaces 2b of the adjacent base portions 2 in the laminated structure.

[0047] In this embodiment, the spacers 4 are strip-shaped and have a width smaller than the width of the arrangement region R in the width direction of the base part 2, and are arranged in a region outside the arrangement region R. In the example of Fig. 1 and Fig. 2, the spacers 4 are provided continuously in the extending direction of the base part 2 at the edge part in the width direction of the base part 2, sandwiching the arrangement region R in the width direction.

[0048] The spacer 4 can be made of, for example, the same material as the base 2, such as polyethylene terephthalate (PET), a UV-curable resin film, a slightly adhesive film, a metal sheet, or a paper sheet. The spacer 4 may also be made of a material that can suppress the generation of static electricity. Examples of such materials include an aluminum sheet, antistatic-coated polyethylene terephthalate, and a conductive carbon sheet. When the spacer 4 is made of a UV-curable resin film or a slightly adhesive film, the spacer 4 may be bonded to the base 2.

[0049] In this embodiment, as shown in FIG. 3 , if the thickness of the base portion 2 from the second surface 2b to the first surface 2a is H1, the height of the spacer 4 is H2, and the average particle size of the solder balls S is H3, then (H1 + H2) is greater than 1 and less than 600 times H3. By making (H1 + H2) greater than 1 time H3, the spacer 4 can form a sufficient space V relative to the size of the solder balls S. This effectively prevents contact between the solder balls S and the base portion 2. Furthermore, by making (H1 + H2) less than 600 times H3, the height of the space V is not excessive, thereby enabling the miniaturization of the solder bump forming member 1A. (H1 + H2) may be greater than 2 times H3, greater than 8 times H3, or greater than 20 times H3. (H1+H2) may be 350 times or less than H3, 100 times or less than H3, or 55 times or less than H3.

[0050] In this embodiment, if the average particle size of the solder balls is H3 and the difference in height between the top 4a of the spacer 4 and the top Sa of the solder ball S is H4, H4 is 0.5 times or more of H3. This allows the space V formed by the spacer 4 to be sufficient for the size of the solder ball S. Therefore, contact between the solder balls S and the base portion 2 can be suitably prevented. H4 may be 1 time or more, or may be 10 times or more, of H3.

[0051] In this embodiment, if the thickness of the base part 2 from the second surface 2b to the first surface 2a is H1 and the difference in height between the top 4a of the spacer 4 and the top Sa of the solder ball S is H4, H1 is greater than 1 / 10 of H4. This allows the base part 2 to have a constant thickness, ensuring sufficient handleability of the base part 2.

[0052] In this embodiment, if the height difference between the top 4a of the spacer 4 and the top Sa of the solder ball S is H4 and the thickness of the base portion 2 at the recess 3 is H5, H4 is 1 / 50 to 10 times H5. By setting H4 to 1 / 50 or more of H5, a sufficient space V can be formed by the spacer 4 relative to the size of the solder ball S. This effectively prevents contact between the solder ball S and the base portion 2. Furthermore, by setting H4 to 10 times H5 or less, the height of the space V does not become excessive, thereby enabling the miniaturization of the solder bump forming member 1A. H4 may be 1 / 10 or more of H5, or 1 / 5 or more of H5. H4 may be 5 times or less of H5, or 2 times or less of H5.

[0053] In this embodiment, if the thickness of the base portion 2 at the recess 3 is H5 and the amount of protrusion of the solder ball S from the recess 3 is H6, H5 may be more than twice H6. In this case, the depth of the recess 3 is sufficient for the amount of protrusion of the solder ball S, and it is possible to prevent the solder ball S from falling off from the recess 3. H5 may be more than 20 times H6, more than 40 times H6, or more than 50 times H6.

[0054] In this embodiment, the height difference H4 between the top 4a of the spacer 4 and the top Sa of the solder ball S may be 10% or less of the thickness H1 of the base portion 2 from the second surface 2b to the first surface 2a. The solder bump forming member 1A has a roll-shaped laminated structure, and by ensuring that the relationship between H4 and H1 satisfies the above-mentioned range, it is possible to prevent the spacer 4 from wrinkling due to the difference in the radius of curvature between the base portion 2 and the spacer 4.

[0055] 4, in this embodiment, the spacer 4 is bonded to the first surface 2a of the base portion 2, and is not bonded to the second surface 2b of the adjacent base portion 2 in the laminated structure. This configuration can prevent the spacer 4 from shifting relative to the base portion 2. Furthermore, when the solder balls S are transferred, the spacer 4 can be prevented from becoming waste separate from the base portion 2.

[0056] 5, the spacers 4 may be bonded to the second surface 2b of the base portion 2, and not bonded to the first surface 2a of the adjacent base portion 2 in the laminated structure. The configuration of FIG. 5 makes it possible to prevent the spacers 4 from interfering with the arrangement region R when arranging the spacers 4. Also, as in the case of FIG. 4, it is possible to prevent the spacers 4 from becoming waste separate from the base portion 2 when transferring the solder balls S.

[0057] When the spacer 4 is made of a non-adhesive material such as a paper sheet, the spacer 4 may be non-bonded to the first surface 2a of one adjacent base portion 2 and the second surface 2b of the other adjacent base portion 2 in the laminated structure, as shown in FIG. 6. In this case, the spacer 4 can be easily removed from the solder bump forming member 1A. By removing the spacer 4 when transferring the solder balls S, problems such as the spacer 4 interfering with the transfer device can be prevented. In addition, it becomes easier to transfer the solder balls S to an area larger than the arrangement area R.

[0058] As shown in Fig. 7, a cover film 5 may be provided between the spacer 4 and the second surface 2b of the base portion 2 adjacent to each other in the laminated structure, while being spaced apart from the solder balls S. In the example of Fig. 7, the cover film 5 is in contact with the second surface 2b of the base portion 2 adjacent to each other in the laminated structure, and is draped over the top portion 4a of one spacer 4 in the width direction of the base portion 2 and the top portion 4a of the other spacer 4 in the width direction of the base portion 2. This arrangement of the cover film 5 improves the shape retention of the space V created by the spacer 4. This more reliably prevents contact between the solder balls S and the base portion 2.

[0059] The cover film 5 may be made of the same material as the base portion 2, such as polyethylene terephthalate (PET), ultraviolet-curable resin film, slightly adhesive film, metal sheet, or paper sheet. The cover film 5 may also be made of engineering plastics or super engineering plastics. Alternatively, the cover film 5 may be made of a composite material containing fillers or fibers, such as the general-purpose plastics listed above, or an inorganic material. In this case, polyamide, polyacetal, polycarbonate, polyphenylene sulfide, polyimide, polyethylene etherimide, polyamideimide, polysulfone, polyether ether ketone, or dust-free paper may be used. To prevent static electricity, aluminum sheet metal materials, conductive carbon, or antistatic coated resin materials may be used.

[0060] The thickness of the cover film 5 may be 1 mm or less from the viewpoint of reducing the thickness during lamination. The thickness of the cover film 5 may be 0.8 mm or less, 0.5 mm or less, 0.3 mm or less, 0.1 mm or less, 0.05 mm or less, or 0.037 mm or less. The thickness of the cover film 5 may be 5 times or less, 3 times or less, or 2 times or less the thickness H1 of the base portion 2.

[0061] When the spacer 4 is bonded to the first surface 2a of the base part 2, the cover film 5 may be unbonded to the second surface 2b of the base part 2 adjacent to the spacer 4 in the laminated structure, as shown in Fig. 8. In this case, the cover film 5 is independent from the base part 2 and the spacer 4, which makes it easier to remove the cover film 5 when transferring the solder balls S, and also broadens the range of materials that can be selected for the cover film 5.

[0062] When the spacer 4 is not bonded to each of the adjacent base portions 2, 2 in the laminated structure, the cover film 5 may be bonded to the spacer 4 as shown in Fig. 9. In this case, the spacer 4 and the cover film 5 are integrated, so that the cover film 5 can be easily removed together with the spacer 4 when transferring the solder balls S. By removing the spacer 4 and the cover film 5 when transferring the solder balls S, problems such as the spacer 4 and the cover film 5 interfering with the transfer device can be prevented.

[0063] As explained above, in the solder bump forming member 1A, the spacers 4 are provided on the first surface 2a of the base portion 2 so as to be higher than the height of the tops Sa of the solder balls S. The arrangement of the spacers 4 allows a certain space V to be formed between the solder balls S held on the base portion 2 and the base portion 2 of the solder bump forming member 1 that overlaps it. Therefore, even when the solder bump forming member 1 is rolled, contact between the solder balls S and the base portion 2 can be prevented. Preventing contact between the solder balls S and the base portion 2 effectively prevents problems such as the solder balls S coming off due to static electricity and poor transfer due to the adhesion of organic matter to the solder balls S.

[0064] In this embodiment, the laminated structure is in a roll shape, and the arrangement region R is provided continuously in the extension direction of the base portion 2 in the central portion in the width direction on the first surface 2a side of the base portion 2. The spacers 4 are also provided continuously in the extension direction of the base portion 2 so as to sandwich the arrangement region R in the width direction. With this configuration, the roll-shaped solder bump forming member 1A can be easily produced by, for example, winding the base portion 2 together with the spacers 4 using a roll-to-roll method. Furthermore, the symmetry of the arrangement of the spacers 4 relative to the arrangement region R allows the solder bump forming member 1A to be uniformly wound and unwound while maintaining the shape retention of the space V by the spacers 4.

[0065] The arrangement of the array region R and the spacers 4 relative to the base portion 2 can be modified in various ways. For example, in the above embodiment, the spacers 4 are provided continuously in the extension direction of the base portion 2 so as to sandwich the array region R in the width direction. However, as shown in FIG. 10, the spacers 4 may be provided intermittently in the extension direction of the base portion 2 so as to sandwich the array region R in the width direction. In this case, the amount of spacers 4 used can be reduced. Furthermore, the spacers 4 can be used as markers for cutting positions when the solder bump forming member 1A is cut for use. Furthermore, when forming a roll-shaped laminated structure, the occurrence of wrinkles in the spacers 4 due to the difference in the radius of curvature between the base portion 2 and the spacers 4 can be suppressed.

[0066] There are no particular restrictions on the spacing between the spacers 4, 4 in the extension direction of the base portion 2, but as an example, as shown in Figure 10, the spacing between the spacers 4, 4 in the extension direction of the base portion 2 may be smaller than the length of the spacer 4 in the extension direction of the base portion 2. In this case, the spacers 4, 4 may be separated by a slit. The spacing between the spacers 4, 4 in the extension direction of the base portion 2 may be equal to the length of the spacer 4 in the extension direction of the base portion 2.

[0067] 11(a), 11(b), 12(a), and 12(b), a plurality of arrangement regions R may be provided at predetermined intervals in the extension direction of the base portion 2 in the central portion in the width direction on the first surface 2a side of the base portion 2. Here, in each of the arrangement regions R, a plurality of recesses 3 are arranged in a lattice pattern of 6 columns by 6 rows, and each recess 3 holds one solder ball S.

[0068] The number of recesses 3 arranged in each of the arrangement regions R can be set arbitrarily. Furthermore, the planar shape of the arrangement region R is not limited to a rectangular shape, and can be other shapes such as a circular shape, an elliptical shape, a triangular shape, or a polygonal shape. The spacing between the arrangement regions R, R in the extension direction of the base portion 2 is also not particularly limited, but the spacing between the arrangement regions R, R in the extension direction of the base portion 2 may be smaller than the length of the arrangement region R in the extension direction of the base portion 2. The spacing between the arrangement regions R, R in the extension direction of the base portion 2 may be equal to the length of the arrangement region R in the extension direction of the base portion 2.

[0069] Even when multiple arrangement regions R are provided at predetermined intervals, various configurations can be adopted for the arrangement of the spacers 4. In the example of Fig. 11(a), as in Fig. 1, the spacers 4 are provided continuously in the extension direction of the base portion 2 at the widthwise edge of the base portion 2 so as to sandwich the arrangement regions R in the widthwise direction. With this configuration, as in the above embodiment, a roll-shaped member for forming solder bumps 1A can be easily produced by, for example, rolling the base portion 2 together with the spacers 4 using a roll-to-roll method.

[0070] 11(b), the spacers 4 are provided between the arrangement regions R, R with a constant width in the width direction of the base portion 2. With this configuration, the spacers 4 can be used as markers for the cutting position when the solder bump forming member 1A is cut for use. Furthermore, when forming a roll-shaped laminated structure, it is possible to prevent the spacers 4 from wrinkling due to the difference in the radius of curvature between the base portion 2 and the spacers 4.

[0071] In the example of FIG. 12(a), the spacers 4 are provided in a frame shape so as to surround each of the array regions R. This configuration allows the spacers 4 to enhance the shape retention of the space V. In the example of FIG. 12(b), similar to the case of FIG. 10, the spacers 4 are provided intermittently along the widthwise edge of the base portion 2 in the extending direction of the base portion 2 so as to sandwich the array regions R in the widthwise direction. Therefore, the same effects as those in the case of FIG. 10 are achieved. Note that in the example of FIG. 12(b), the positions of the intermittently provided spacers 4 correspond to the respective corners of the array regions R. This arrangement of the spacers 4 allows the amount of spacers 4 used to be reduced while maintaining the shape retention of the space V due to the spacers 4. [Second embodiment]

[0072] 13 is a schematic perspective view showing a solder bump forming member according to a second embodiment of the present disclosure. As shown in FIG. 13, a solder bump forming member 1B according to the second embodiment has a sheet-like laminated structure, which differs from the first embodiment, which has a roll-like laminated structure.

[0073] The solder bump forming member 1B has a plurality of rectangular (here, square) base portions 2. An arrangement region R in which solder balls S are held is provided in the center of each of the first surface 2a sides of the base portions 2. In the example of FIG. 13, a plurality of recesses 3 are arranged in a lattice pattern of 6 columns by 6 rows in the arrangement region R, and one solder ball S is held in each recess 3. The spacers 4 are arranged in a frame shape around the edge of the first surface 2a side of the base portion 2 so as to surround the arrangement region R.

[0074] The layered structure of the solder bump forming member 1B is the same as that of the solder bump forming member 1A (see FIG. 2). In the solder bump forming member 1B, the size relationships between (H1+H2) and H3, between H3 and H4, between H1 and H4, between H4 and H5, and between H5 and H6 are the same as those in the solder bump forming member 1A (see FIG. 3). The spacer configurations shown in FIGS. 4 to 6 can also be applied to the solder bump forming member 1B. The cover film configurations shown in FIGS. 7 to 9 can also be applied to the solder bump forming member 1B. The effects achieved by these configurations are the same as those in the first embodiment.

[0075] In the solder bump forming member 1B, too, spacers 4 are provided on the first surface 2a of the base portion 2 so as to be higher than the height of the tops Sa of the solder balls S. The arrangement of the spacers 4 allows a certain space V (see FIG. 2) to be formed between the solder balls S held on the base portion 2 and the base portion 2 of the solder bump forming member 1 that overlaps it. Therefore, even when the solder bump forming member 1 is formed into a sheet, contact between the solder balls S and the base portion 2 can be prevented. Preventing contact between the solder balls S and the base portion 2 effectively prevents problems such as the loss of the solder balls S due to static electricity and poor transfer due to the adhesion of organic matter to the solder balls S.

[0076] In this embodiment, the laminated structure is sheet-shaped (or plate-shaped), and the arrangement region R is provided in the central portion on the first surface 2a side of the base portion 2. The spacers 4 are provided on the edge portion of the base portion 2 so as to surround the arrangement region R. With this configuration, the symmetry of the arrangement of the spacers 4 with respect to the arrangement region R makes it possible to suitably maintain the shape retention of the space V by the spacers 4.

[0077] Unlike member 1A for forming solder bumps, member 1B is not curved by rolling, and therefore a hard material can be used for at least one of base 2, spacer 4, and cover film 5. In this case, hard materials include inorganic materials such as silicon wafers, resin materials such as hard plastics, and metal materials such as aluminum plates. The use of a hard material not only improves the handleability of member 1B for forming solder bumps, but also improves the shape retention of space V.

[0078] In the solder bump forming member 1B as well, it is possible to arbitrarily set the number of recesses 3 arranged in each of the arrangement regions R. Furthermore, the planar shape of the arrangement regions R is not limited to a rectangular shape, and can be other shapes such as a circular shape, an elliptical shape, a triangular shape, or a polygonal shape.

[0079] Various modifications can also be made to the arrangement of the spacers 4. For example, as shown in FIG. 14(a), the spacers 4 may be provided only on two opposing sides of the edge of the base portion 2. This configuration facilitates the arrangement of the spacers 4 because the spacers 4 are arranged in only one direction. Alternatively, as shown in FIG. 14(b), the spacers 4 may be provided intermittently on the edge of the base portion 2. This achieves the same effects as those shown in FIGS. 10 and 12(b). In the example of FIG. 14(b), the positions of the intermittently provided spacers 4 correspond to the respective corners of the arrangement region R, as in the example of FIG. 12(b). This arrangement of the spacers 4 reduces the amount of spacers 4 used while maintaining the shape of the space V. [Variations]

[0080] The present disclosure is not limited to the above-described embodiments. For example, in all of the above-described embodiments, the spacers 4 are disposed in an area outside the arrangement region R. However, the spacers 4 may be disposed inside the arrangement region R if the transfer of the solder balls S is not hindered. In this case, the spacers 4 may be disposed, for example, on the top of a wall separating adjacent recesses 3, 3. The spacers 4 may also cover the solder balls S in part of the arrangement region R. In this case, when using the solder bump forming members 1A, 1B, the transfer of the solder balls S can be performed using the arrangement region R that is not covered by the spacers 4.

[0081] 15, the recesses 3 may be omitted and the solder balls S may be held directly on the first surface 2a of the base part 2. In this case, for example, by imparting slight adhesion to the first surface 2a of the base part 2, it is possible to prevent the solder balls S from falling off the base part 2.

[0082] The adhesive that holds the solder balls S to the first surface 2a of the base portion 2 may be any adhesive that has a tack strength sufficient to prevent the solder balls S from easily falling off the first surface 2a. From the viewpoint of maintaining the connectivity of the solder bumps after transfer, the adhesive is preferably an organic adhesive that does not change in quality or decompose at the transfer temperature of the solder balls S, and is a material that does not cause oxidation or corrosion to the solder. Examples of adhesives that can be used include acrylic, silicone, and rubber-based adhesives. Since applying a thicker adhesive does not increase the effect, there is no particular limit to the thickness of the adhesive. From an economical viewpoint, the thickness of the adhesive is preferably 100 μm or less.

[0083] In the case where recesses 3 are omitted, the thickness H1 of the base portion 2 from the second surface 2b to the first surface 2a, the height H2 of the spacers 4, the average particle size H3 of the solder balls S, and the difference in height H4 between the tops 4a of the spacers 4 and the tops Sa of the solder balls S are as shown in FIG. 15. In this embodiment, (H1 + H2) may be greater than 1 time and less than 600 times H3. H4 may be greater than 0.5 times H3, and H1 may be greater than 1 / 10 of H4. Furthermore, H4 may be greater than 1 / 50 and less than 10 times H5. This provides the same effects as those described above. [Explanation of symbols]

[0084] 1A, 1B...solder bump forming member, 2...base portion, 2a...first surface, 2b...second surface, 3...recess, 4...spacer, 5...cover film, 4a...top portion, R...arrangement region, S...solder ball, Sa...top portion.

Claims

1. A solder bump forming member having a roll-shaped or sheet-shaped laminated structure, a base portion having a first surface and a second surface opposite the first surface; an arrangement area in which the plurality of solder balls held on the base portion are arranged, and a spacer are provided on the first surface side of the base portion; The height position of the top of the spacer from the base is higher than the height position of the top of the solder ball from the base.

2. 2. The solder bump forming member according to claim 1, wherein, when the thickness of the base portion from the second surface to the first surface is H1, the height of the spacer is H2, and the average particle size of the solder balls is H3, (H1 + H2) is greater than 1 time and less than 600 times H3.

3. A solder bump forming member as described in claim 1 or 2, wherein when the height of the spacer is H2, the average particle size of the solder balls is H3, and the difference in height between the top of the spacer and the top of the solder balls is H4, H4 is at least 0.5 times H3 and less than H2.

4. A solder bump forming member according to any one of claims 1 to 3, wherein when the thickness of the base portion from the second surface to the first surface is H1 and the difference in height between the top of the spacer and the top of the solder ball is H4, H1 is greater than 1 / 10 of H4.

5. 5. The solder bump forming member according to claim 1, wherein the arrangement region is provided with a plurality of recesses for holding the respective solder balls.

6. 6. A solder bump forming member according to claim 5, wherein H4 is the height difference between the top of the spacer and the top of the solder ball, and H5 is the thickness of the base portion at the recess, and H4 is 1 / 50 or more and 10 times or less of H5.

7. A solder bump forming member as described in claim 5 or 6, wherein when the thickness of the base portion from the second surface to the first surface is H1, the thickness of the base portion at the recess is H5, and the amount of protrusion of the solder ball from the recess is H6, H5 is at least twice H6 but less than H1.

8. A solder bump forming member according to any one of claims 1 to 7, wherein the spacer is bonded to the first surface side of the base portion and is not bonded to the second surface side of an adjacent base portion in the laminated structure.

9. A solder bump forming member according to any one of claims 1 to 7, wherein the spacer is bonded to the second surface side of the base portion and is not bonded to the first surface side of an adjacent base portion in the laminated structure.

10. A solder bump forming member according to any one of claims 1 to 7, wherein the spacer is not bonded to the first surface side of one of the adjacent base portions and the second surface side of the other of the adjacent base portions in the laminated structure.

11. A solder bump forming member according to any one of claims 1 to 7, wherein a cover film is provided between the spacer and the second surface of the adjacent base portion in the laminated structure, spaced apart from the solder ball.

12. the spacer is bonded to the first surface side of the base portion, 12. The member for forming a solder bump according to claim 11, wherein the cover film is not bonded to the spacer and the adjacent base portion in the laminate structure.

13. the spacer is not bonded to each of the adjacent base portions in the laminated structure, 12. The member for forming solder bumps according to claim 11, wherein the cover film is bonded to the spacer.

14. the laminated structure is in a roll form; the array region is provided continuously in an extension direction of the base portion at a central portion in a width direction on the first surface side of the base portion, 14. The member for forming a solder bump according to claim 1, wherein the spacers are provided continuously in the extending direction of the base portion so as to sandwich the arrangement region in the width direction.

15. the laminated structure is in a roll form; the array region is provided at a central portion in the width direction on the first surface side of the base portion at a predetermined interval in the extending direction of the base portion, 14. The member for forming a solder bump according to claim 1, wherein the spacers are provided continuously in the extending direction of the base portion so as to sandwich the arrangement region in the width direction.

16. the laminated structure is in a sheet form, the array region is provided in a central portion on the first surface side of the base portion, 14. The member for forming solder bumps according to claim 1, wherein the spacer is provided so as to surround the arrangement region.

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