Solder bump forming component

Abstract

The present invention provides a solder bump forming member that can prevent contact between solder balls and the base material when the material is rolled or sheeted. [Solution] Solder bump forming members 1A, 1B are solder bump forming members having a roll-shaped or sheet-shaped laminated structure, and include a base portion 2 having a first surface 2a and a second surface 2b opposite to the first surface 2a. On the first surface 2a side of the base portion 2, there is an array region R where a plurality of solder balls S held by the base portion 2 are lined up, and a spacer 4 is provided, and the height position of the top 4a of the spacer 4 on the base portion 2 is higher than the height position of the top Sa of the solder ball S on the base portion 2.

Description

Technical Field

[0001] The present disclosure relates to a member for forming solder bumps.

Background Art

[0002] As one method for mounting electronic components with high density, flip chip mounting is known. In flip chip mounting, for example, solder bumps are previously formed 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. Thereby, a connection structure between circuit members can be obtained.

[0003] As a technique for forming solder bumps on electrodes, for example, there is a solder bump forming method described in Patent Document 1. In this conventional solder bump forming method, a positioning plate in which a plurality of recesses are formed corresponding to the mutual intervals of electrodes on a substrate is used. This positioning plate is used as a member for forming solder bumps for the electrodes, and solder balls are arranged in respective recesses of the positioning plate. By rolling a transfer roll whose outer peripheral surface is an adhesive surface on the surface of the positioning plate, the solder balls are transferred to the adhesive surface of the transfer roll. Thereafter, by rolling the transfer roll on the electrodes of a substrate provided with an adhesive material, the solder balls are transferred from the adhesive surface of the transfer roll to the electrodes of the substrate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In actual electronic component mounting scenarios, it is anticipated that the solder bump forming material described above will be transported and stored in rolls or sheets. However, in configurations where the solder balls protrude from recesses, such as the positioning plate described in Patent Document 1 (see Figure 2(b) of Patent Document 1), there is a risk that the protruding portions of the solder balls may come into contact with the base portion of the solder bump forming material that overlaps them when the solder bump forming material is rolled or sheeted. In this case, the shape of the solder balls may be distorted, potentially affecting the reliability of electronic component mounting. Furthermore, contact between the solder balls and the base portion may lead to problems such as solder ball detachment due to static electricity, or transfer defects due to the adhesion of organic matter to the solder balls.

[0006] This disclosure was made to solve the above-mentioned problems and aims to provide a solder bump forming member that can prevent contact between solder balls and the base portion when the material is rolled or sheeted. [Means for solving the problem]

[0007] A solder bump forming member relating to one aspect of the present disclosure is a solder bump forming member having a roll-shaped or sheet-shaped laminated structure, comprising a base portion having a first surface and a second surface opposite to the first surface, wherein the first surface side of the base portion is provided with an arrangement region in which a plurality of solder balls held on the first surface are lined up and a spacer, 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 as to be higher than the height of the top of the solder ball. This arrangement of spacers creates a certain space between the solder ball held by 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 rolled or sheeted, contact between the solder ball and the base portion can be prevented. By preventing contact between the solder ball and the base portion, problems such as solder ball detachment due to static electricity and transfer failure due to the adhesion of organic matter to the solder ball can be effectively prevented.

[0009] If 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 ball is H3, then (H1 + H2) may be greater than 1 times H3 and 600 times or less. This allows for sufficient space to be formed by the spacer relative to the size of the solder ball. Therefore, contact between the solder ball and the base portion can be effectively prevented. Furthermore, the height of the space is not excessive, allowing for miniaturization of the solder bump forming component.

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

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

[0012] The array region may be provided with multiple recesses to hold each of the solder balls. In this case, the solder balls are positioned by the recesses, thus ensuring the reliability of the solder ball transfer.

[0013] If 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 in the recess, then H4 may be between 1 / 50 and 10 times H5. This allows for sufficient space to be formed by the spacer relative to the size of the solder ball. Therefore, contact between the solder ball and the base can be effectively 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 portion in the recess is H5 and the amount of solder ball protrusion from the recess is H6, then H5 may be twice or more than H6. In this case, the depth of the recess will be sufficient for the amount of solder ball protrusion, and the occurrence of solder ball detachment from 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 adjacent base parts in the laminated structure. This configuration prevents the spacer from shifting relative to the base. It also avoids the spacer becoming separate waste from the base during solder ball transfer.

[0016] The spacer may be bonded to the second surface of the base portion but not to the first surface of adjacent base portions in the stacked structure. This configuration prevents the spacer from interfering with the arrangement area when the spacer is placed. It also avoids the spacer becoming separate waste from the base portion when transferring solder balls.

[0017] The spacer may not be joined to the first surface of one adjacent base portion and the second surface of the other base portion in the laminated structure. In this case, the spacer can be easily removed. Therefore, it is possible to prevent the spacer from interfering with the transfer device during solder ball transfer. 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 laminated structure, spaced apart from the solder ball. In this case, the space created by the spacer is maintained by the cover film. Therefore, contact between the solder ball and the base portion can be prevented more reliably.

[0019] The spacer may be bonded to the first surface of the base, while the cover film may be unbonded to the spacer and to adjacent spacers on the base in the laminated structure. In this case, since the cover film is independent of the base and spacer, it becomes easier to remove the cover film, and the range of material selection for the cover film can be broadened.

[0020] The spacers are not bonded to each adjacent base portion in the laminated structure, and the cover film may be bonded to the spacers. In this case, the cover film can be easily removed together with the spacers. By removing the spacers and cover film during solder ball transfer, problems such as interference between the spacers and cover film and the transfer device can be prevented.

[0021] The laminated structure is roll-shaped, and the array region is provided continuously in the extending direction of the base portion at the central part in the width direction on the first surface side of the base portion, and the spacers may be provided continuously in the extending direction of the base portion so as to sandwich the array region in the width direction. In this case, for example, a roll-shaped solder bump forming member can be easily manufactured by winding the base portion together with the spacers using a roll-to-roll method. Furthermore, due to the symmetry of the arrangement of the spacers with respect to the array region, the winding and unwinding of the solder bump forming member can be performed uniformly while maintaining the shape retention of the space by the spacers.

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

[0023] The laminated structure is in a sheet shape, the array region is provided in the central portion on the first surface side of the base body portion, and the spacers may be provided so as to surround the array region. In this case, due to the symmetry of the arrangement of the spacers with respect to the array region, the shape retention of the space by the spacers can be preferably maintained.

Advantages of the Invention

[0024] According to the present disclosure, contact between the solder balls and the base body portion can be prevented when rolling or sheeting.

Brief Description of the Drawings

[0025] [Figure 1] It is a schematic perspective view showing a solder bump forming member according to a first embodiment of the present disclosure. [Figure 2] It is a schematic cross-sectional view showing the laminated structure of the solder bump forming member shown in FIG. 1. [Figure 3] It is a schematic cross-sectional view showing the relationship between the height position of the top of the spacer and the height position of the top of the solder ball. [Figure 4] It is a schematic exploded cross-sectional view showing an example of the configuration of the spacer. [Figure 5] It is a schematic exploded cross-sectional view showing another example of the configuration of the spacer. [Figure 6] It is a schematic exploded cross-sectional view showing still another example of the configuration of the spacer. [Figure 7] It is a schematic cross-sectional view showing the laminated structure of the solder bump forming member when the cover film is arranged. [Figure 8] This is a schematic exploded cross-sectional view showing an example of the structure of a cover film. [Figure 9] This is a schematic exploded cross-sectional view showing another example of the cover film's configuration. [Figure 10] This is a schematic plan view showing another example of spacer placement. [Figure 11] (a) and (b) are schematic plan views showing alternative examples of the arrangement of solder balls and spacers. [Figure 12] (a) and (b) are schematic plan views showing further alternative examples of the arrangement of solder balls and spacers. [Figure 13] This is a schematic perspective view showing a solder bump forming member according to a second embodiment of the present disclosure. [Figure 14] (a) and (b) are schematic plan views showing alternative examples of the arrangement of solder balls and spacers. [Figure 15] This is a schematic cross-sectional view showing the relationship between the height position of the top of the spacer and the height position of the top of the solder ball in a modified example of the present disclosure. [Modes for carrying out the invention]

[0026] Hereinafter, with reference to the drawings, preferred embodiments of a solder bump forming member relating to one aspect of this disclosure will be described in detail.

[0027] In this specification, numerical ranges indicated using "~" include the numbers before and after "~" as the minimum and maximum values, respectively. In this specification, the upper or lower limits of numerical ranges described in stages may be replaced with the upper or lower limits of numerical ranges in other stages. [First Embodiment]

[0028] Figure 1 is a schematic perspective view showing a solder bump forming member according to the first embodiment of this disclosure. Figure 2 is a schematic cross-sectional view showing the laminated structure of the solder bump forming member shown in Figure 1. The solder bump forming member 1A shown in Figures 1 and 2 is a member used, for example, to form solder bumps (transfer of solder balls S) on electrodes of circuit members. In the example shown in Figures 1 and 2, the solder bump forming member 1A has a roll-shaped laminated structure and is stored, transported, and used in this state. When the solder bump forming member 1A and the solder bump forming member 1B described later are housed in a container, an inert gas such as nitrogen may be purged into the container.

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

[0030] Examples of constituent materials for the base portion 2 include inorganic materials such as silicon, various ceramics, glass, and stainless steel, and organic materials such as various resins. The constituent material for the base portion 2 may also be a material with high light transmittance. Examples of such materials include polyethylene terephthalate, transparent (colorless) polyimide, and polyamide. The constituent material for the base portion 2 may also be a heat-resistant material that does not change at the melting point of the solder ball S. The constituent material for the base portion 2 may also be a material that does not change by alloying or reacting with the materials constituting the solder ball S.

[0031] The constituent material of the base portion 2 may be a flexible film material. Examples of such materials include polyethylene terephthalate, polyethylene naphthalate, polyvinyl chloride resin, polystyrene, polyethylene polyphenylene sulfide, and polycarbonate. From the viewpoint of improving the handling of the base portion 2, deformation can be suppressed by increasing the thickness of the aforementioned material.

[0032] From the viewpoint of improving the accuracy of transferring solder balls S to the electrodes, engineering plastics, super engineering plastics, materials compounded with fillers or fibers into the general-purpose plastics mentioned above, and inorganic materials can be used as the constituent material of the base part 2. In this case, for example, polyamide, polyacetal, polycarbonate, polyphenylene sulfide, polyimide, polyetherimide, polyamideimide, polysulfone, polyetheretherketone, etc. can be used.

[0033] An array region R is provided on the first surface 2a side of the base portion 2, where solder balls S are held. In the examples of Figures 1 and 2, the array region R is provided in the central part in the width direction on the first surface 2a side of the base portion 2, and is continuous in the extending direction of the base portion 2 with a constant width. The array region R is provided with a plurality of recesses 3 for holding solder balls S. In the examples of Figures 1 and 2, the plurality of recesses 3 are arranged in a grid of 6 columns × n rows (where n is an integer) in the array region R, and one solder ball S is held in each recess 3.

[0034] The recess 3 can be formed using known methods such as imprinting, photolithography, machining, and laser processing. In particular, when using nanoimprinting, the recess 3 can be formed accurately in a relatively short process by pressing the desired mold. By providing such a recess 3, the solder ball S is positioned by the recess 3, thus ensuring the reliability of the transfer of the solder ball S.

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

[0036] From the viewpoint of preventing the solder ball S from falling out of the recess 3 at times other than when transferring to the electrode, the height of the solder ball S may be 3.00 or less when the depth of the recess 3 is set to 1. When designing the depth of the recess 3, the average particle size of multiple solder balls S may be used as the diameter of the solder ball S.

[0037] In the examples in Figures 1 and 2, the planar shape of the recess 3 is square relative to the circular solder ball S in plan view. The planar shape of the recess 3 may be various shapes other than a square, such as an ellipse, a triangle, a rectangle, or a polygon. Also, in the examples in 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, with the opening area increasing from the bottom surface 3b to the opening surface 3a. The bottom surface 3b of the recess 3 is not limited to a flat surface, but may be a concave curved surface, for example.

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

[0039] The solder ball 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. From the viewpoint of obtaining good conductivity reliability, the solder ball S may contain Ag or Cu from the aforementioned elements. By containing Ag or Cu in the solder ball S, the melting point of the solder ball S can be lowered to about 220°C and the bonding strength with the electrode can be improved. The solder ball S may be particles having a metal film on the surface of resin particles. The solder ball S may consist of a single metal particle or a plurality of metal particles.

[0040] The average particle size of the solder ball S is, for example, between 1 μm and 35 μm. The average particle size of the solder ball S may also be 25 μm or less, 20 μm or less, or 15 μm or less. The average particle size of the solder ball S may also 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 ball S can be measured using various methods appropriate to the size. Examples of measurement methods include dynamic light scattering, laser diffraction, centrifugal sedimentation, electrical detection band method, and resonant mass spectrometry.

[0041] Other methods for measuring the average particle size of solder balls S include measuring particle size based on images obtained by optical microscopes or electron microscopes. Specific devices include flow-type particle image analyzers, microtracs, and Coulter counters. The average particle size of solder balls S can be calculated, for example, based on the projected area equivalent diameter (the diameter of a circle with an area equal to the projected area of ​​the particle) when observing the solder balls S from a direction perpendicular to the first surface 2a of the solder bump forming member 1A.

[0042] The CV value of the solder ball S is calculated by multiplying the value obtained by dividing the standard deviation of the particle size measured by the method described above by the average particle size by 100. The CV value of the solder ball S may be 20% or less from the viewpoint of achieving better conductivity and insulation reliability. The CV value of the solder ball S may be 10% or less, or 7% or less. There is no particular lower limit to the CV value of the solder ball S. The CV value of the solder ball S may be 1% or more, or 2% or more.

[0043] The solder ball S held in the recess 3 may be in contact with the bottom surface 3b or the inner wall surface 3c of the recess 3. A portion of the solder ball S may be flat at the point of contact with the bottom surface 3b or the inner wall surface 3c. By having the solder ball S in contact with the bottom surface 3b or the inner wall surface 3c of the recess 3, the occurrence of the solder ball S falling out of the recess 3 can be suppressed at times other than when it is being transferred to the electrode.

[0044] Alignment marks (not shown) may be provided on the first surface 2a of the base portion 2. The alignment marks can be formed, for example, by creating an uneven surface on the first surface 2a of the base portion 2, printing with ink or pigment, printing with inorganic material by plating or sputtering, or burning with a laser. In plan view, the alignment marks may be, for example, circular, double circular, multi-circular, triangular, rectangular, polygonal, or multi-gonal forms thereof. The alignment marks may be made of magnetic material or material that absorbs, reflects, or diffracts electromagnetic waves. In this case, the shape of the alignment marks is not particularly limited.

[0045] By detecting alignment marks with an imaging device such as a camera, the alignment of the electrode to be formed and the solder ball S in the recess 3 becomes easier during solder bump formation. Therefore, the accuracy of transferring the solder ball S to the electrode can be improved. One or more alignment marks are sufficient on the first surface 2a side, but providing multiple marks can further improve the accuracy of alignment. If the base part 2 is transparent, for example, additional alignment marks may be provided on the second surface 2b side.

[0046] As shown in Figures 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 ball S held by the base portion 2 and the base portion 2 that overlaps it in the roll-shaped laminated structure (see Figure 2). By forming space V, it is possible to suppress the solder ball S held in the recess 3 from coming into contact with the second surface 2b of the adjacent base portion 2 in the laminated structure.

[0047] In this embodiment, the spacer 4 is strip-shaped with a width smaller than the width of the array region R in the width direction of the base portion 2, and is positioned in a region outside the array region R. In the examples of Figures 1 and 2, the spacer 4 is provided continuously in the extending direction of the base portion 2 at the width direction edge of the base portion 2 so as to sandwich the array region R in the width direction.

[0048] The spacer 4 can be made of, for example, the same material as the base 2, polyethylene terephthalate (PET), UV-curable resin film, slightly adhesive film, metal sheet, paper sheet, etc. The spacer 4 may also be made of a material capable of suppressing the generation of static electricity. Examples of such materials include aluminum sheets, polyethylene terephthalate with an antistatic coating, and conductive carbon sheets. If 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 Figure 3, when 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 ball S is H3, then (H1 + H2) is greater than 1 times H3 and 600 times or less. By making (H1 + H2) greater than 1 times H3, a sufficient space V formed by the spacer 4 can be created relative to the size of the solder ball S. Therefore, contact between the solder ball S and the base portion 2 can be effectively prevented. Furthermore, by making (H1 + H2) 600 times or less of H3, the height of the space V does not become excessive, and the solder bump forming member 1A can be miniaturized. (H1 + H2) may be 2 times or more of H3, 8 times or more of H3, or 20 times or more of 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, when the average particle size of the solder balls is H3 and the height difference 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 H3. This allows for the formation of a sufficient space V by the spacer 4 relative to the size of the solder ball S. Therefore, contact between the solder ball S and the base 2 can be effectively prevented. H4 may be 1 time or more than H3, or 10 times or more.

[0051] In this embodiment, if the thickness of the base portion 2 from the second surface 2b to the first surface 2a is H1, and the height difference between the top 4a of the spacer 4 and the top Sa of the solder ball S is H4, then H1 is greater than 1 / 10 of H4. As a result, the base portion 2 has a constant thickness, and the handling of the base portion 2 can be sufficiently ensured.

[0052] In this embodiment, when 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 in the recess 3 is H5, then H4 is between 1 / 50 and 10 times H5. By making H4 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. Therefore, contact between the solder ball S and the base portion 2 can be effectively prevented. Furthermore, by making H4 10 times or less of H5, the height of the space V does not become excessive, and the solder bump forming member 1A can be miniaturized. 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 in the recess 3 is H5 and the amount of solder ball S protruding from the recess 3 is H6, then H5 may be twice or more the amount of H6. In this case, the depth of the recess 3 becomes sufficient for the amount of solder ball S protruding, and the occurrence of solder ball S falling out of the recess 3 can be suppressed. H5 may be 20 times or more the amount of H6, 40 times or more the amount of H6, or 50 times or more the amount of 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, but by ensuring that the relationship between H4 and H1 satisfies the aforementioned range, the occurrence of wrinkles in the spacer 4 due to the difference in radius of curvature between the base portion 2 and the spacer 4 can be suppressed.

[0055] In this embodiment, as shown in Figure 4, the spacer 4 is joined to the first surface 2a of the base portion 2, but is not joined to the second surface 2b of adjacent base portions 2 in the laminated structure. This configuration prevents the spacer 4 from shifting relative to the base portion 2. Furthermore, it avoids the spacer 4 becoming a separate waste object from the base portion 2 during the transfer of solder balls S.

[0056] As shown in Figure 5, the spacer 4 may be bonded to the second surface 2b of the base portion 2, but not to the first surface 2a of adjacent base portions 2 in the laminated structure. According to the configuration in Figure 5, interference between the spacer 4 and the array region R during placement of the spacer 4 can be prevented. Also, as in the case of Figure 4, it is possible to avoid the spacer 4 becoming separate waste from the base portion 2 during the transfer of solder balls S.

[0057] When the spacer 4 is made of a non-adhesive material such as a paper sheet, as shown in Figure 6, the spacer 4 may not be joined to the first surface 2a of one adjacent base portion 2 and to the second surface 2b of the other base portion 2 in the laminated structure. 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 Figure 7, a cover film 5 may be provided between the spacer 4 and the second surface 2b of adjacent base portion 2 in the laminated structure, spaced apart from the solder ball S. In the example in Figure 7, the cover film 5 is in contact with the second surface 2b of adjacent base portion 2 in the laminated structure, and is stretched across the top 4a of one spacer 4 in the width direction of the base portion 2 and the top 4a of the other spacer 4 in the width direction of the base portion 2. This arrangement of the cover film 5 enhances the shape retention of the space V by the spacer 4. Therefore, contact between the solder ball S and the base portion 2 can be prevented more reliably.

[0059] The constituent materials of the cover film 5 can include, for example, the same materials as those used for the base part 2, polyethylene terephthalate (PET), UV-curable resin film, slightly tacky film, metal sheet, paper sheet, etc. Alternatively, engineering plastics and super engineering plastics can be used as constituent materials for the cover film 5. Furthermore, materials compounded with fillers or fibers into the aforementioned general-purpose plastics, and inorganic materials can also be used. In this case, for example, polyamide, polyacetal, polycarbonate, polyphenylene sulfide, polyimide, polyether ether imide, polyamide imide, polysulfone, polyether ether ketone, and dust-free paper can be used. Additionally, from the viewpoint of preventing static electricity generation, aluminum sheet metal materials, conductive carbon, and resin materials with antistatic coatings can be used.

[0060] The thickness of the cover film 5 may be 1 mm or less from the viewpoint of reducing the thickness when laminated. 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 part 2.

[0061] When the spacer 4 is bonded to the first surface 2a of the base portion 2, the cover film 5 may not be bonded to the spacer 4 and the second surface 2b of the adjacent base portion 2 in the laminated structure, as shown in Figure 8. In this case, since the cover film 5 is independent of the base portion 2 and the spacer 4, it becomes easier to remove the cover film 5 when transferring the solder balls S, and the range of material selection for the cover film 5 is broadened.

[0062] If the spacer 4 is not joined to each of the adjacent base portions 2,2 in the laminated structure, the cover film 5 may be joined to the spacer 4, as shown in Figure 9. In this case, since the spacer 4 and the cover film 5 are integrated, 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 cover film 5 when transferring the solder balls S, problems such as the spacer 4 and cover film 5 interfering with the transfer device can be prevented.

[0063] As explained above, in the solder bump forming member 1A, a spacer 4 is provided on the first surface 2a of the base portion 2 such that it is higher than the height of the top Sa of the solder ball S. The arrangement of the spacer 4 allows a certain space V to be formed between the solder ball S held by 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 up, contact between the solder ball S and the base portion 2 can be prevented. By preventing contact between the solder ball S and the base portion 2, problems such as the solder ball S coming off due to static electricity and transfer defects due to the adhesion of organic matter to the solder ball S can be effectively prevented.

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

[0065] Various modifications can be applied to the arrangement of the array region R and spacers 4 relative to the base portion 2. For example, in the above embodiment, the spacers 4 are provided continuously in the extending direction of the base portion 2 so as to sandwich the array region R in the width direction, but as shown in Figure 10, the spacers 4 may be provided intermittently in the extending 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. In addition, the spacers 4 can be used as markers for the cutting position when the solder bump forming member 1A is cut and used. Furthermore, when forming a roll-shaped laminated structure, the occurrence of wrinkles in the spacers 4 due to the difference in radius of curvature between the base portion 2 and the spacers 4 can be suppressed.

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

[0067] Furthermore, in the above embodiment, the array region R is provided continuously in the extending direction of the base portion 2, but as shown in Figures 11(a), 11(b), 12(a), and 12(b), for example, multiple array regions R may be provided at predetermined intervals in the extending direction of the base portion 2 in the central part in the width direction on the first surface 2a side of the base portion 2. In this case, in each of the array regions R, a plurality of recesses 3 are arranged in a 6x6 grid, and one solder ball S is held in each recess 3.

[0068] The number of recesses 3 in each of the array regions R can be set arbitrarily. Furthermore, the planar shape of the array region R is not limited to a rectangular shape, but can be a circular, elliptical, triangular, or polygonal shape. There are no particular restrictions on the spacing between the array regions R, R with respect to the extending direction of the base portion 2, although the spacing between the array regions R, R with respect to the extending direction of the base portion 2 may be smaller than the length of the array region R with respect to the extending direction of the base portion 2. The spacing between the array regions R, R with respect to the extending direction of the base portion 2 may be equal to the length of the array region R with respect to the extending direction of the base portion 2.

[0069] Even when multiple array regions R are provided at predetermined intervals, the arrangement of the spacers 4 can take various configurations. In the example shown in Figure 11(a), similar to the case in Figure 1, the spacers 4 are provided continuously in the extending direction of the base portion 2 at the widthwise edge of the base portion 2 so as to sandwich the array regions R in the widthwise direction. With such a configuration, similar to the above embodiment, a roll-shaped solder bump forming member 1A can be easily manufactured by winding the base portion 2 together with the spacers 4 using, for example, a roll-to-roll method.

[0070] In the example shown in Figure 11(b), the spacer 4 is provided with a constant width in the width direction of the base portion 2 between the array regions R, R. With this configuration, the spacer 4 can be used as a marker for the cutting position when the solder bump forming member 1A is cut and used. Furthermore, when forming a roll-shaped laminated structure, the occurrence of wrinkles in the spacer 4 due to the difference in radius of curvature between the base portion 2 and the spacer 4 can be suppressed.

[0071] In the example shown in Figure 12(a), the spacers 4 are arranged in a frame-like shape, surrounding each of the array regions R. This configuration enhances the shape retention of the space V by the spacers 4. In the example shown in Figure 12(b), similar to the case in Figure 10, the spacers 4 are provided intermittently along the widthwise edge of the base portion 2, sandwiching the array region R in the widthwise direction. Therefore, the same effects as in Figure 10 are achieved. In the example shown in Figure 12(b), the positions of the intermittently provided spacers 4 correspond to each corner of the array region R. This arrangement of spacers 4 reduces the amount of spacers 4 used while maintaining the shape retention of the space V by the spacers 4. [Second Embodiment]

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

[0073] The solder bump forming member 1B has multiple rectangular (in this case, square) base portions 2. An array region R is provided in the central part of the first surface 2a side of each base portion 2, where solder balls S are held. In the example in Figure 13, multiple recesses 3 are arranged in a 6x6 grid pattern in the array region R, and one solder ball S is held in each recess 3. The spacer 4 is arranged in a frame shape on the edge of the first surface 2a side of the base portion 2, surrounding the array region R.

[0074] The laminated structure of the solder bump forming member 1B is the same as that of the solder bump forming member 1A (see Figure 2). In the solder bump forming member 1B, the relative sizes of (H1+H2) and H3, H3 and H4, H1 and H4, H4 and H5, and H5 and H6 are the same as those of the solder bump forming member 1A (see Figure 3). Furthermore, the spacer configurations shown in Figures 4 to 6 can also be applied to the solder bump forming member 1B. The cover film configurations shown in Figures 7 to 9 can also be applied to the solder bump forming member 1B. The effects and advantages resulting from these configurations are the same as those of the first embodiment.

[0075] In the solder bump forming member 1B, a spacer 4 is provided on the first surface 2a of the base portion 2 such that it is higher than the height of the top Sa of the solder ball S. The arrangement of the spacer 4 allows a certain space V (see Figure 2) to be formed between the solder ball S held by 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 made into a sheet, contact between the solder ball S and the base portion 2 can be prevented. By preventing contact between the solder ball S and the base portion 2, problems such as the solder ball S coming off due to static electricity and transfer defects due to the adhesion of organic matter to the solder ball S can be effectively prevented.

[0076] In this embodiment, the laminated structure is sheet-like (or plate-like), and the arrangement region R is provided in the central part of the first surface 2a side of the base portion 2. The spacers 4 are provided on the edges 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 allows for the desirable maintenance of the shape of the space V by the spacers 4.

[0077] Unlike solder bump forming member 1A, solder bump forming member 1B does not undergo curvature due to rolling, so a rigid material can be used for at least one of the base portion 2, spacer 4, and cover film 5. Examples of rigid materials in this case include inorganic materials such as silicon wafers, resin materials such as hard plastics, and metallic materials such as aluminum plates. Using a rigid material improves the handling of solder bump forming member 1B and also improves the shape retention of the space V.

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

[0079] Various modifications can be applied to the arrangement of the spacers 4. For example, as shown in Figure 14(a), the spacers 4 may be provided only on two opposing edges of the base portion 2. With such a configuration, the arrangement of the spacers 4 is limited to one direction, making the arrangement of the spacers 4 easier. Alternatively, as shown in Figure 14(b), the spacers 4 may be provided intermittently along the edges of the base portion 2. In this case, the same effects as in Figures 10 and 12(b) are achieved. In the example of Figure 14(b), similar to the example of Figure 12(b), the positions of the intermittently provided spacers 4 correspond to the corners of the arrangement region R. With such an arrangement of spacers 4, the amount of spacers 4 used can be reduced while maintaining the shape retention of the space V provided by the spacers 4. [Differentiation]

[0080] This disclosure is not limited to the embodiments described above. For example, in the embodiments described above, the spacer 4 is positioned in a region outside the array region R, but the spacer 4 may be positioned inside the array region R if it does not hinder the transfer of solder balls S. In this case, the spacer 4 may be positioned, for example, at the top of the wall separating adjacent recesses 3, 3. The spacer 4 may also cover the solder balls S in a part of the array region R. In this case, when using the solder bump forming members 1A and 1B, the transfer of solder balls S can be performed using the array region R that is not covered by the spacer 4.

[0081] Furthermore, in the above embodiments, the solder balls S are held in the recesses 3 in the array region R, but as shown in Figure 15, the recesses 3 may be omitted, and the solder balls S may be held directly on the first surface 2a of the base portion 2. In this case, for example, by providing slight tackiness to the first surface 2a of the base portion 2, the detachment of the solder balls S from the base portion 2 can be suppressed.

[0082] The adhesive used to hold the solder balls S to the first surface 2a of the base portion 2 should have sufficient tack force to prevent the solder balls S attached to the first surface 2a from easily falling off. From the viewpoint of maintaining the connectivity of the solder bumps after transfer, the adhesive is preferably an organic adhesive that does not deteriorate or decompose at the transfer temperature of the solder balls S, and is made of a material that does not cause oxidation or corrosion to the solder. For example, acrylic, silicone, or rubber-based adhesives can be used. Applying a thicker layer of adhesive does not increase its effectiveness, so there are no particular restrictions on the thickness of the adhesive. From an economic standpoint, the thickness of the adhesive is preferably 100 μm or less.

[0083] When the recess 3 is omitted, the thickness H1 of the base portion 2 from the second surface 2b to the first surface 2a, the height H2 of the spacer 4, the average particle size H3 of the solder ball S, and the height difference H4 between the top 4a of the spacer 4 and the top Sa of the solder ball S are as shown in Figure 15. In this embodiment as well, (H1 + H2) may be greater than 1 times H3 and 600 times or less. H4 may be 0.5 times or more of H3, and H1 may be greater than 1 / 10 of H4. Also, H4 may be 1 / 50 or more and 10 times or less of H5. This produces the same effects as described above. [Explanation of Symbols]

[0084] 1A, 1B... Solder bump forming member, 2... Base part, 2a... First surface, 2b... Second surface, 3... Recess, 4... Spacer, 5... Cover film, 4a... Top, R... Alignment area, S... Solder ball, Sa... Top.

Claims

1. A solder bump forming member having a roll-shaped or sheet-shaped laminated structure, It comprises a base portion having a first surface and a second surface opposite to the first surface, On the first surface side of the base portion, there is an array region where a plurality of solder balls held by the base portion are arranged, and a spacer. A solder bump forming member wherein 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.

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 times H3 and 600 times or less.

3. The solder bump forming member according to claim 1 or 2, wherein when the average particle size of the solder ball is H3, and the height difference between the top of the spacer and the top of the solder ball is H4, H4 is 0.5 times or more of H3.

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 height difference between the top of the spacer and the top of the solder ball is H4, H1 is greater than 1 / 10 of H4.

5. The solder bump forming member according to any one of claims 1 to 4, wherein the array region is provided with a plurality of recesses for holding each of the solder balls.

6. The solder bump forming member according to claim 5, wherein when 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 in the recess is H5, H4 is 1 / 50 or more and 10 times or less of H5.

7. The solder bump forming member according to claim 5 or 6, wherein when the thickness of the base portion in the recess is H5 and the amount of protrusion of the solder ball from the recess is H6, H5 is twice or more than H6.

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

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

10. The solder bump forming member according to any one of claims 1 to 7, wherein the spacer is not joined to the first surface side of one of the adjacent base portions and to the second surface side of the other base portion 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 joined to the first surface side of the base portion, The solder bump forming member according to claim 11, wherein the cover film is not joined to the spacer and adjacent base portions in the laminated structure.

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

14. The aforementioned laminated structure is in the form of a roll, The aforementioned arrangement region is provided in the central part in the width direction on the first surface side of the base portion, continuously in the extending direction of the base portion. The solder bump forming member according to any one of claims 1 to 13, wherein the spacer is provided continuously in the extending direction of the base portion so as to sandwich the arrangement region in the width direction.

15. The aforementioned laminated structure is in the form of a roll, The aforementioned arrangement regions are provided in a plurality at predetermined intervals in the extending direction of the base portion, in the central portion in the width direction on the first surface side of the base portion. The solder bump forming member according to any one of claims 1 to 13, wherein the spacer is provided continuously in the extending direction of the base portion so as to sandwich the arrangement region in the width direction.

16. The aforementioned laminated structure is in the form of a sheet, The aforementioned arrangement region is provided in the central portion of the first surface side of the base portion, The solder bump forming member according to any one of claims 1 to 13, wherein the spacer is provided so as to surround the array region.

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