Solder bump forming component

Abstract

To provide a method for manufacturing a solder bump-equipped component that enables better connection between electrodes. [Solution] A method for manufacturing a member with solder bumps, comprising: a preparation step of preparing a base body having a plurality of recesses having irregularities on its bottom surface; a placement step of arranging solder particles in the recesses; and a pressing step of pressing the base body and a substrate having electrodes with the solder particles and electrodes facing each other to bring the solder particles and electrodes into contact, thereby forming solder bumps on the electrodes having depressions in at least a part of the surface.

Description

【Technical Field】 【0001】 The present invention relates to a method for manufacturing a member with solder bumps, a member with solder bumps, and a member for forming solder bumps. 【Background Art】 【0002】 When mounting a semiconductor chip on a circuit board by a flip chip method, a step of transferring a flux to an adhesion surface of a solder bump formed on the semiconductor chip and its vicinity with the circuit board, and a step of flip chip connecting the semiconductor chip on which the flux has been transferred to the circuit board are known (for example, Patent Document 1). 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Laid-Open No. 1995-078847 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 Generally, the surface of a solder bump has a smooth curved surface. Therefore, when using the technique of Patent Document 1, when pressing the solder bump against an electrode on the circuit board, the flux may be pushed out from the surface of the solder bump. If a sufficient amount of flux is not ensured during joining, it becomes difficult for the solder to wet and spread properly, and there is a possibility that a portion where the connection between the electrodes is not properly made may occur. 【0005】 The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a member with solder bumps capable of realizing better connection between electrodes. Another object of the present invention is to provide a member with solder bumps and a member for forming solder bumps. 【Means for Solving the Problems】 <00 One aspect of the present invention relates to a method for manufacturing a member with solder bumps, comprising: a preparation step of preparing a substrate having a plurality of recesses having irregularities on its bottom surface; a placement step of arranging solder particles in the recesses; and a pressing step of pressing the substrate and a substrate having electrodes with the solder particles and electrodes facing each other to bring the solder particles and electrodes into contact, thereby forming solder bumps on the electrodes having depressions on at least a part of the surface. 【0007】 Generally, when performing solder bump joining, liquid flux is applied to a wiring board having metal electrodes such as Au and Cu, and solder bumps are pressed onto it to join. From the viewpoint of shortening the process, reducing raw material costs, and suppressing metal electrode corrosion, it is desirable to use a small amount of flux. On the other hand, if the amount of flux is small, there is a risk that the flux may be pushed away from the solder bump surface or that the flux will flow at the joining temperature, making it impossible to secure the amount of flux necessary to join the solder bump to the electrode. Therefore, the inventors conducted research to better capture flux on the solder bump itself while keeping the amount of flux used low, and completed the present invention. In the present invention, a solder bump forming member is made using a substrate having irregularities on its bottom surface, and a solder bump is formed by pressing this onto the electrode. As a result, the irregularities on the bottom surface of the substrate are reflected on the solder bump surface, and a solder bump having depressions on at least a part of its surface can be formed on the electrode. With solder bump-equipped components obtained in this way, the indentations on the solder bump surface trap flux during connection between electrodes, resulting in better connection between electrodes. This makes it possible to create connection structures that achieve both excellent insulation reliability and conductivity reliability, even with only a small amount of flux. 【0008】 In one embodiment of a method for manufacturing a solder bumped member, the solder particles may be heated during the pressing step. 【0009】 One embodiment of the manufacturing method for a component with solder bumps may further include a reduction step in which solder particles are exposed to a reducing atmosphere before the placement step. 【0010】 One embodiment of the manufacturing method for a solder bumped component may further include a reduction step, after the placement step and before the pressing step, in which the solder particles are exposed to a reducing atmosphere. 【0011】 In one embodiment of a method for manufacturing a solder bumped component, the solder particles may be heated in a reducing atmosphere during the pressing step. 【0012】 One embodiment of the manufacturing method for a solder bumped member may further include a removal step after the pressing step, in which the base is removed from the substrate. 【0013】 One embodiment of the method for manufacturing a component with solder bumps may further include a cleaning step after the removal step to remove solder particles that are not bonded to the electrodes. 【0014】 One aspect of the present invention relates to a solder bump member comprising a substrate having electrodes and solder bumps on the electrodes, wherein a recess is formed on at least a portion of the surface of the solder bump. 【0015】 In one embodiment of a component with solder bumps, the recess depth of the solder bump may be 25% or less of the solder bump height. 【0016】 In one embodiment of a component with solder bumps, adjacent solder bumps may be independent of each other. 【0017】 In one embodiment of a component with solder bumps, the height of the solder bump may be smaller than the diameter of the solder bump in the planar direction. 【0018】 One aspect of the present invention relates to a solder bump forming member comprising a substrate having a plurality of recesses having irregularities on its bottom surface, and solder particles within the recesses. 【0019】 In one embodiment of a solder bump forming member, the height difference between the recessed and raised parts of the uneven surface may be 20% or less of the average particle diameter of the solder particles. 【0020】 In one aspect of the solder bump forming member, the average particle size of the solder particles may be 1 to 35 μm and the C.V. value may be 20% or less. 【Effect of the Invention】 【0021】 According to the present invention, it is possible to provide a method for manufacturing a member with solder bumps capable of achieving better connection between electrodes. Further, according to the present invention, it is possible to provide a member with solder bumps obtained by the manufacturing method, and a solder bump forming member for obtaining the member with solder bumps. 【Brief Description of the Drawings】 【0022】 [Figure 1] FIG. 1 is a cross-sectional view schematically showing a solder bump forming member according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing an example of a substrate. [Figure 3] FIG. 3(a) is a plan view schematically showing an example of a substrate 60, and FIG. 3(b) is a cross-sectional view taken along line Ib-Ib of FIG. 3(a). [Figure 4] FIGS. 4(a) to (d) are cross-sectional views schematically showing examples of the cross-sectional shape of the recesses of the substrate. [Figure 5] FIG. 5 is a cross-sectional view schematically showing a state in which solder fine particles 111 are accommodated in the recess 62 of the substrate 60. [Figure 6] FIGS. 6(a) and 6(b) are cross-sectional views schematically showing an example of the manufacturing process of a member with solder bumps. [Figure 7] FIGS. 7(a) and 7(b) are cross-sectional views schematically showing an example of the manufacturing process of a connection structure. [Figure 8] FIG. 8 is a SEM photograph of a solder bump forming member obtained by Production Example 1. 【Mode for Carrying Out the Invention】 【0023】 The embodiments described below are not limited to the following forms. Unless otherwise specified, the materials exemplified below may be used individually or in combination of two or more. The content of each component in the composition means the total amount of multiple substances present in the composition, unless otherwise specified, if multiple substances corresponding to each component are present in the composition. Numerical ranges indicated using "~" indicate a range that includes the numbers written before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit of a numerical range in one stage may be replaced with the upper or lower limit of a numerical range in another stage. In numerical ranges described in this specification, the upper or lower limit of a numerical range may be replaced with the values ​​shown in the examples. 【0024】 <Solder bump forming component> Figure 1 is a schematic cross-sectional view of a solder bump forming member according to one embodiment. The solder bump forming member 10 comprises a base body 60 having a plurality of recesses with irregularities on its bottom surface, and solder particles 1 in the recesses 62. The recesses with irregularities on their bottom surface can also be described as recesses with protrusions on their bottom surface. In Figure 1, the tops of the protrusions are schematically curved, and the number of protrusions is depicted uniformly in each recess, but it is sufficient that the protrusions form depressions on the solder bump surface, and the tops of the protrusions may be sharper, and the number of protrusions may differ between recesses. In a predetermined longitudinal cross-section of the solder bump forming member 10, one solder particle 1 is arranged so as to be separated from an adjacent solder particle 1 and aligned in the lateral direction (left-right direction in Figure 1). The solder particles 1 may be in contact with their sides and / or bottom surfaces within the recesses 62. The solder bump forming component may be in the form of a film (solder bump forming film), a sheet (solder bump forming sheet), or a substrate (solder bump forming substrate). 【0025】 In the solder bump forming member 10, some of the solder particles 1 may or may not protrude from the recess. 【0026】 When a part of the solder particle 1 protrudes from the recess, it can be said that at least the top of the solder particle 1 protrudes from the recess 62 of the solder bump forming member 10 (protrudes from the main surface of the substrate 60). In a cross-sectional view perpendicular to the main surface of the solder bump forming member 10, when the depth of the recess 62 is H1 and the height from the substrate surface to the top of the solder particle 1 is H2, H1 < (H1 + H2), that is, 0 < H2 may be satisfied. The height H2 of the solder particle 1 is the height from the surface of the substrate 60 to the apex of the solder particle 1 in the cross-sectional view. The depth H1 of the recess 62 is measured based on the average value of the protrusion heights existing on the bottom surface. In FIG. 1, since the protrusion heights are schematically drawn as constant, H1 is the depth from the protrusion apex to the substrate surface. However, since the protrusion height does not have to be constant (the bottom surface of the recess does not have to be uniformly uneven), when there is variation in the protrusion height, H1 is measured based on the average value of the protrusion heights as described above. The degree of protrusion of the solder particle 1 is not particularly limited, but from the viewpoint of suppressing the dropout of the solder particle 1, the upper limit of the ratio (H2 / H1) of H2 to H1 can be set to 2.00. 【0027】 The depth H1 of the recess 62 and the height H2 from the substrate surface to the top of the solder particle 1 can be measured by a laser microscope. 【0028】 (Solder particle) The average particle diameter of the solder particle 1 may be 1 to 35 μm. The average particle diameter of the solder particle 1 may be 30 μm or less, 25 μm or less, 20 μm or less, or 15 μm or less. Also, the average particle diameter of the solder particle 1 may be 2 μm or more, 3 μm or more, or 5 μm or more. 【0029】 The average particle diameter of solder particles 1 can be measured using various methods appropriate to the size. For example, methods such as dynamic light scattering, laser diffraction, centrifugal sedimentation, electrical detection band method, and resonant mass measurement can be used. Furthermore, methods for measuring particle size from images obtained by optical microscopes, electron microscopes, etc., can be used. Specific devices include flow-type particle image analyzers, microtrac, and Coulter counters. The average particle diameter of solder particles 1 can be defined as the projected area equivalent diameter (the diameter of a circle with an area equal to the projected area of ​​the particle) when the solder particles 1 are observed from a direction perpendicular to the main surface of the solder bump forming member 10. 【0030】 The height difference between the concave and convex parts of the uneven surface (the height of the protrusions) may be 20% or less of the average particle diameter of the solder particles 1. From the viewpoint of maintaining the shape of the solder bumps, the height difference between the concave and convex parts of the uneven surface may be 20% or less, 15% or less, or 10% or less of the average particle diameter of the solder particles 1. The lower limit of the height difference between the concave and convex parts of the uneven surface can be, for example, 2% or more of the average particle diameter of the solder particles 1. From this viewpoint, for example, when the solder particle size is 4 μm, the height difference between the concave and convex parts of the uneven surface may be 0.8 μm or less, 0.6 μm or less, or 0.4 μm or less. The lower limit of the height difference between the concave and convex parts of the uneven surface can be, for example, 0.08 μm or more. 【0031】 The height difference between the concave and convex parts of the surface (the height of the protrusions) can be measured using a laser microscope. The height difference between the recesses and protrusions of the uneven surface on the bottom surface (the height of the protrusions) is calculated using the average value of the height differences (protrusion heights) present on the bottom surface. In this specification, the height difference between the recesses and protrusions of the uneven surface formed on the bottom surface of the recesses of the solder bump forming member 10 is calculated as follows: For 100 recesses of any solder bump forming member 10, the protrusion height is measured by observation using a laser microscope, and the protrusion height for each recess is calculated. Furthermore, the average value of the protrusion heights of the 100 recesses is calculated and taken as the height difference between the recesses and protrusions of the uneven surface on the bottom surface of the recesses of the solder bump forming member 10 (the height of the protrusions). 【0032】 The CV value of solder particle 1 may be 20% or less. From the viewpoint of achieving better conductivity and insulation reliability, the CV value of solder particle 1 may be 20% or less, 10% or less, or 7% or less. Furthermore, there is no particular lower limit to the CV value of solder particle 1. For example, it may be 1% or more, or 2% or more. 【0033】 The CV value of solder particle 1 is calculated by multiplying the value obtained by dividing the standard deviation of the particle diameter measured by the method described above by the average particle diameter by 100. 【0034】 Solder particles 1 may contain tin or a tin alloy. Examples of tin alloys that can be used include In-Sn alloy, In-Sn-Ag alloy, Sn-Au alloy, Sn-Bi alloy, Sn-Bi-Ag alloy, Sn-Ag-Cu alloy, Sn-Cu alloy, etc. Specific examples of these tin alloys are listed below. ·In-Sn (In52 mass%, Sn48 mass%, melting point 118℃) ·In-Sn-Ag (In20% by mass, Sn77.2% by mass, Ag2.8% by mass, melting point 175℃) • Sn-Bi (Sn 43% by mass, Bi 57% by mass, melting point 138°C) • Sn-Bi-Ag (Sn 42% by mass, Bi 57% by mass, Ag 1% by mass; melting point 139°C) • Sn-Ag-Cu (Sn 96.5% by mass, Ag 3% by mass, Cu 0.5% by mass; melting point 217°C) • Sn-Cu (Sn 99.3% by mass, Cu 0.7% by mass, melting point 227°C) ·Sn-Au (Sn21.0% by mass, Au79.0% by mass, melting point 278℃) 【0035】 Solder particles may contain indium or an indium alloy. Examples of indium alloys include In-Bi alloys and In-Ag alloys. Specific examples of these indium alloys are listed below. In-Bi (In 66.3% by mass, Bi 33.7% by mass, melting point 72°C) In-Bi (In 33.0% by mass, Bi 67.0% by mass, melting point 109°C) In-Ag (In 97.0% by mass, Ag 3.0% by mass, melting point 145℃) 【0036】 Depending on the application of solder particles 1 (temperature during connection), the above tin alloy or indium alloy can be selected. For example, when solder particles 1 are used for fusion at low temperatures, In-Sn alloy or Sn-Bi alloy can be used, in which case fusion can be achieved at 150°C or below. When materials with high melting points, such as Sn-Ag-Cu alloy or Sn-Cu alloy, are used, high reliability can be maintained even after being left at high temperatures. 【0037】 Solder particles 1 may contain one or more elements selected from Ag, Cu, Ni, Bi, Zn, Pd, Pb, Au, P, and B. Of these elements, Ag or Cu may be included from the following viewpoint. That is, by including Ag or Cu in solder particles 1, the melting point of solder particles 1 can be lowered to about 220°C, and the bonding strength with the electrode is further improved, making it easier to obtain better conductivity reliability. 【0038】 The Cu content of the solder particles 1 is, for example, 0.05 to 10 mass%, and may be 0.1 to 5 mass% or 0.2 to 3 mass%. When the Cu content is 0.05 mass% or higher, it is easier to achieve better solder connection reliability. Also, when the Cu content is 10 mass% or lower, the solder particles 1 tend to have a low melting point and excellent wettability, and as a result, the connection reliability of the joint made by the solder particles 1 tends to be good. 【0039】 The Ag content of solder particles 1 is, for example, 0.05 to 10 mass%, and may be 0.1 to 5 mass% or 0.2 to 3 mass%. When the Ag content is 0.05 mass% or higher, it is easier to achieve better solder connection reliability. Furthermore, when the Ag content is 10 mass% or lower, the solder particles 1 tend to have a low melting point and excellent wettability, and as a result, the connection reliability of the joint made by the solder particles 1 tends to be good. 【0040】 (Base) As the material constituting the base body 60, for example, inorganic materials such as silicon, various ceramics, glass, and metals such as stainless steel, as well as organic materials such as various resins, can be used. Of these, the base body 60 may be a heat-resistant material that does not change in quality at the melting temperature of the solder fine particles. Alternatively, the base body 60 may be a heat-resistant material that does not deform at the temperature at which the solder fine particles melt. Furthermore, the base body 60 may be a material that does not alloy with or react with the material constituting the solder fine particles and change in quality. The recesses 62 of the base body 60 can be formed by known methods such as cutting, photolithography, and imprinting. In particular, using the imprinting method allows for the formation of recesses 62 of precise size in a short number of steps. 【0041】 The surface of the substrate 60 may have a coating layer. From the viewpoint of broadening the selectivity of materials that can be used for the substrate 60, the coating layer may be made of a material that does not easily or does not alloy with the material constituting the solder fine particles, and may be made of a heat-resistant material that does not deteriorate at the melting temperature of the solder fine particles. Inorganic or organic materials can be used as the coating layer. Examples of usable coating layers include inorganic materials having a strong oxide layer on the surface such as aluminum and chromium, oxides such as titanium oxide, nitrides such as boron nitride, carbon-based materials such as diamond-like carbon (DLC), diamond, and graphite, and high heat-resistant resins such as fluororesins and polyimides. The coating layer may also serve to adjust the wettability with solder. By providing a coating layer on the surface of the substrate 60, the wettability with solder can be appropriately adjusted according to the intended use. 【0042】 Methods for forming the coating layer include lamination, solution dipping, coating, painting, impregnation, sputtering, and plating. 【0043】 From the viewpoint of making it easier to set the conditions for the transfer process, the material of the substrate 60 may be similar in physical properties to or the same as the electrode to which the solder particles are transferred and the substrate on which the electrode is formed. For example, if the materials have similar or the same coefficient of thermal expansion (CTE), positional displacement is less likely to occur during the transfer of solder particles. 【0044】 Alignment marks may be provided on the substrate 60. Alignment marks may also be provided on the substrate side having electrodes. It is preferable that the alignment marks be readable by a camera. When transferring solder particles onto the electrodes, the alignment marks on the substrate 60 and the alignment marks on the substrate having electrodes can be read by a camera mounted on a positioning device, making it possible to accurately determine the position of the recess 62 containing the solder particles and the position of the electrode onto which the solder particles are transferred. By providing alignment marks on the substrate 60 and the substrate having electrodes, solder particles can be transferred onto the electrodes with high positional accuracy. 【0045】 Alignment marks should be present in at least one location on the base 60. Having two or more alignment marks will improve positional accuracy. 【0046】 The specific configuration of the base 60 is described below. 【0047】 (Organic material, single layer) The substrate 60 may be composed of an organic material. The organic material may be a polymer material, and thermoplastic materials, thermosetting materials, photocurable materials, etc., can be used. Using an organic material broadens the range of physical properties that can be selected, making it easier to form a substrate 60 that suits the purpose. For example, if the substrate 60 (including the recess 62) is made of an organic material, it is easier to bend and stretch it. If the substrate 60 is made of an organic material, various methods can be used to form the recess 62. Methods for forming the recess 62 include imprinting, photolithography, cutting, and laser processing. According to the imprinting method, a mold having the desired shape can be pressed onto the substrate 60 made of an organic material to form an arbitrary shape on the surface. By forming a convex pattern on the mold and pressing it onto the substrate 60 made of an organic material, a recess 62 having the desired pattern can be formed. When a photocurable resin is used to form the recess 62, the photocurable resin is applied to the mold, exposed to light, and then the mold is peeled off to form a substrate 60 having a recess 62. In addition, in the case of cutting, the recess 62 can be formed with a drill or the like. 【0048】 (Organic material multilayer) The substrate may be composed of multiple organic materials. The substrate may have multiple layers, and each of the multiple layers may be composed of a different organic material. The organic material may be a polymer material, and thermoplastic materials, thermosetting materials, photocurable materials, etc., can be used. The substrate may have two layers composed of organic materials, and a recess may be formed in the organic material layer on one side. By using a multilayer structure, the materials of each layer can be selected to differentiate functions, such as selecting a material with appropriate wettability with solder for the recess that comes into contact with solder. For example, Figure 2 is a schematic cross-sectional view showing an example of a substrate. The substrate 600 comprises a base layer 601 and a recess layer 602. The base layer 601 is a layer that supports the recess layer 602, and the recess layer 602 is a layer in which a recess 62 is formed by processing. A resin material with excellent heat resistance and dimensional stability can be used for the base layer 601, and a material with excellent processability for the recess 62 can be selected for the recess layer 602. For example, a thermoplastic resin such as polyethylene terephthalate or polyimide can be used for the base layer 601, and a thermosetting resin capable of forming recesses 62 with an imprint mold can be used for the recess layer 602. For example, by sandwiching a thermosetting resin between polyethylene terephthalate and an imprint mold and heating and pressurizing it, a substrate 600 (including the recesses 62) with excellent flatness can be obtained. Also, when forming the recesses 62 using a photocurable material, a material with high light transmittance may be used for the base layer 601. Examples of materials with high light transmittance include polyethylene terephthalate, transparent (colorless type) polyimide, polyamide, etc. When forming the recesses 62 using a photocurable material, for example, an appropriate amount of the photocurable material is applied to the surface of the imprint mold, a polyethylene terephthalate film is placed on top of it, and ultraviolet light is irradiated from the polyethylene terephthalate side while applying pressure with a roller. Then, after curing the photocurable material, the imprint mold is peeled off to obtain a substrate 600 having a layer of polyethylene terephthalate and a layer of photocurable material, with the recess 62 formed of the photocurable material. The material composition of the inner wall and bottom surface of the recess 62 can be changed. For example, the inner wall and bottom surface of the recess 62 can be made of the same resin material.Furthermore, the inner wall and bottom surface of the recess 62 can be made of different resin materials (for example, a thermosetting material and a thermoplastic material). 【0049】 Photosensitive materials may be used as organic materials. Examples of photosensitive materials include positive-type photosensitive materials and negative-type photosensitive materials. For example, a recess 62 can be formed by forming a photosensitive material to a uniform thickness on the surface of a thermoplastic polyethylene terephthalate film and then performing exposure and development (photolithography). The method using exposure and development is widely used in the manufacture of semiconductors, wiring boards, etc., and is a highly versatile method. In addition to exposure using a mask, direct writing methods such as direct laser exposure can also be used as exposure methods. 【0050】 By making the base layer 601 thicker than the material forming the recessed layer 602, the overall physical properties of the substrate 600 can be dominated by the properties of the base layer 601. This allows the base layer 601 to compensate for any weaknesses in the material forming the recessed layer 602. For example, even if the material of the recessed layer 602 is prone to thermal shrinkage, selecting a material that is less prone to thermal shrinkage for the base layer 601 and making the base layer 601 thicker than the material forming the recessed layer 602 can suppress deformation during heating. 【0051】 Organic materials can be appropriately selected according to the purpose, such as a combination of a resin material with excellent heat resistance or dimensional stability and a material that exhibits minimal component leaching at the melting temperature of solder particles, or a combination of a resin material with excellent heat resistance or dimensional stability and a material with suitable wettability with solder. 【0052】 As described above, the substrate may be a substrate 600 composed of a base layer 601 and a recess layer 602. For example, by using a photosensitive material for the recess layer 602, a recess 62 can be fabricated by photolithography. By using a photo- or thermosetting material, a thermoplastic material, etc. for the recess layer 602, a recess 62 can be fabricated by imprinting. Since the properties of the entire substrate can be adjusted by changing the thickness of the base layer 601, a substrate with desired properties can be fabricated. 【0053】 (Inorganic material, single layer (opaque)) The substrate 60 may be composed of an inorganic material. From the viewpoint of easily controlling the elution of components and the generation of foreign matter, for example, silicon (silicon wafer), stainless steel, aluminum, etc. can be used as the inorganic material. When these materials are used in semiconductor packaging processes, etc., contamination countermeasures are easy, and it is easy to achieve high yield and stable production. For example, when transferring solder particles formed in the recesses 62 to electrodes on a silicon wafer, if the substrate 60 is made from a silicon wafer, the substrate and the substrate will be made of materials with similar or the same CTE. This makes it difficult for misalignment, warping, etc. to occur, and enables transfer to an accurate position. Methods for forming the recesses 62 include processing by laser, cutting, dry etching or wet etching, electron beam lithography (e.g., FIB processing), etc. Dry etching is widely used in the fabrication of semiconductors, MEMS, etc., and can process inorganic materials with high precision from the micron order to the nano order. 【0054】 (Inorganic material, single layer (transparent)) Glass, quartz, sapphire, etc., can be used as the substrate 60. Because these materials are transparent, alignment is easy when transferring solder particles in the recesses 62 to another substrate on which electrodes are formed. Methods for forming the recesses 62 include laser processing, cutting, dry etching or wet etching, electron beam lithography (e.g., FIB processing), etc. 【0055】 The advantage of using inorganic materials is their superior dimensional stability compared to organic materials. When transferring solder particles from the recess 62 onto the electrode, high positional accuracy can be achieved. For example, when transferring solder particles to multiple electrodes with micrometer-order size and pitch, using an inorganic material with superior dimensional stability allows the solder particles to be transferred to the same position on each electrode. 【0056】 (Organic-inorganic composite material) The substrate may be composed of multiple materials. The substrate may have multiple layers, and each of the multiple layers may be composed of a different material. As an organic-inorganic composite material, for example, a combination of an inorganic material and an organic material can be used. The combination of an inorganic material and an organic material makes it easier to achieve both dimensional stability and processability of the recess 62. An example of a substrate having a combination of an inorganic material and an organic material is a substrate comprising a base layer 601 made of an inorganic material such as silicon, various ceramics, glass, or a metal such as stainless steel, and a recess layer 602 made of an organic material. Such a substrate can be obtained, for example, by forming a photosensitive material on the surface of a silicon wafer and forming a recess by exposure and development. The inner wall and bottom surface of the recess 62 may be made of a photosensitive material, or the inner wall of the recess 62 may be made of a photosensitive material and the bottom surface may be made of a silicon wafer. The configuration of the recess 62 can be appropriately selected according to purposes such as wettability with solder particles in the recess 62 and ease of transfer to electrodes. When the inner wall and bottom surface of the recess 62 are composed of a photosensitive material, a method can be used to create the recess 62 by forming a photosensitive material layer on the silicon wafer surface by depositing and curing the photosensitive material, then depositing another photosensitive material layer on the surface of this layer, and performing exposure and development. In this case, the photosensitive material on the silicon wafer surface and the photosensitive material provided on the outermost layer may have different compositions. The photosensitive material can be appropriately selected considering the wettability and contamination properties of solder particles. When transferring the solder particles formed in the recess 62 onto the electrode, the surface of the outermost photosensitive material layer may come into contact with the electrode or the surface of the substrate having the electrode. Therefore, a photosensitive material that does not damage the electrode and substrate, or contaminate the electrode and substrate, can be appropriately selected. The photosensitive material may be a material that prevents the elution of uncured components and contamination by halogen-based materials, silicone-based materials, etc. The photosensitive material may be a material with high resistance to reducing atmospheres, flux, etc., when transferring solder particles to the electrode. For example, the photosensitive material may be resistant to reducing atmospheres such as formic acid, hydrogen, and hydrogen radicals. Furthermore, the photosensitive material may be highly resistant to the temperature at which solder particles are transferred to the electrode.Specifically, the photosensitive material may be a material that can withstand temperatures between 100°C and 300°C. Since the melting point of solder particles varies depending on their constituent materials, the heat resistance temperature of the photosensitive material can also be selected to match the solder material being used. When using tin-silver-copper solder (e.g., SAC305 (melting point 219°C)), which is a lead-free solder widely used in electronic equipment, a material with a heat resistance of 220°C or higher, and especially a heat resistance of 260°C or higher used in reflow processes, can be used. When using tin-bismuth solder (e.g., SnBi58 (melting point 139°C)), a material with a heat resistance of 140°C or higher can be used, and a material with a heat resistance of 160°C or higher will have a wider industrial likelihood of use. When using indium solder (melting point 159°C), a material with a heat resistance of 170°C or higher can be used. When using indium-tin solder (e.g., melting point 120°C), materials with heat resistance of 130°C or higher can be used. 【0057】 Other substrates include those having recesses 62 formed from a thermosetting or thermoplastic resin on a stainless steel plate. This substrate can be obtained by sandwiching a thermosetting material (resin) between a stainless steel plate and an imprint mold, heating under pressure, and then removing the imprint mold. Another substrate is one having recesses 62 formed from a photocurable material on a glass plate. This substrate can be obtained by coating a photocurable material onto a glass plate, curing the photocurable material by exposing it to light while pressing an imprint mold onto it, and then removing the imprint mold. When forming the recesses 62 using an imprint mold, the material composition of the inner wall and bottom surface of the recesses 62 can be changed by adjusting the pressure conditions. For example, if the pressure conditions are relaxed, the inner wall and bottom surface of the recesses 62 can be made of the same resin material. On the other hand, if the pressure conditions are strong, the inner wall of the recesses 62 can be made of resin material and the bottom surface can be made of inorganic material. 【0058】 As the base layer 601 material, a composite material containing glass fibers, fillers, etc., and resin components can also be used. Examples of composite materials include copper-clad laminates for wiring boards. By applying a photosensitive material, thermosetting resin, photocurable resin, etc., to the surface of the copper-clad laminate, the recesses 62 can be formed as described above. Although copper-clad laminates mainly contain a large amount of resin material, the CTE can be made low by combining them with glass fibers, various fillers, etc., thereby ensuring the dimensional stability described above. When electrodes are formed on a copper-clad laminate, forming the recesses 62 on the same copper-clad laminate makes the CTE of the substrate and the base material the same or close to the CTE. This makes it easier to align the solder particles when transferring them into the recesses 62, and reduces the likelihood of misalignment. 【0059】 A packaging sealant can also be used as the material for the recessed layer 602. The sealant can be solid, liquid, or film-type. The recessed layer 62 can be formed by laminating the sealant in a thin layer on glass, a silicon wafer, etc., and then applying pressure and heating with an imprint mold. 【0060】 The uneven shape at the bottom surface of the recess of the substrate may be formed by pressing a mold having the desired shape (for example, a mold with multiple convex parts having irregularities at the tip) onto a substrate made of an organic material, as in imprint technology, or by applying a photocurable resin to the mold, exposing it to light, and then peeling off the mold. 【0061】 The uneven surface may be formed by post-processing a substrate having a flat recessed bottom surface. For example, uneven surfaces can be formed on the bottom of recesses by wet etching, dry etching, etc. Alternatively, uneven surfaces can be formed on the bottom of recesses using a blasting method that involves spraying an abrasive containing hard fine particles at high pressure. 【0062】 The recess may have uneven surfaces other than the bottom surface. The uneven surfaces other than the bottom surface only need to be sufficient to maintain the shape of the recess and not hinder bump formation on the electrode. 【0063】 <Component with solder bumps> A solder bump member comprises a substrate having electrodes and solder bumps on the electrodes, with depressions formed on at least a portion of the surface of the solder bumps. To facilitate securing the amount of flux necessary to bond the solder bumps to the electrodes, the solder bump member may have depressions at least on the top of the surface of the solder bumps. A solder bump member can be called a solder bump electrode substrate. 【0064】 Specific examples of metal electrodes for solder bumped components include electrodes made of copper, copper / nickel, copper / nickel / gold, copper / nickel / palladium, copper / nickel / palladium / gold, copper / nickel / gold, copper / palladium, copper / palladium / gold, copper / tin, copper / silver, indium tin oxide, etc. The electrodes can be formed by electroless plating, electrolytic plating, sputtering, or etching of metal foil. 【0065】 The depth of the depression on the solder bump surface may be 25% or less of the solder bump height. From the viewpoint of maintaining the solder bump shape, the depth of the depression on the solder bump surface may be 25% or less of the solder bump height, 15% or less, or 10% or less. The lower limit of the depression on the solder bump surface can be, for example, 2% or more of the solder bump height. From this viewpoint, for example, the depression depth of a solder bump with a bump height of 3.6 μm may be 0.9 μm or less, 0.54 μm or less, or 0.36 μm or less. The lower limit of the depression on the solder bump surface can be, for example, 0.07 μm or more. The solder bump height is the height from the electrode surface to the top of the solder bump when the solder bump has no depression (assuming it is spherical). 【0066】 The depth of the indentation on the solder bump surface and the height of the solder bump can be measured using a laser microscope. 【0067】 On a component with solder bumps, adjacent solder bumps may be independent of each other. 【0068】 From the viewpoint of connectivity when obtaining a connecting structure using a bumped member, the bump pitch may be the same as the pitch of the base recess; however, if the solder bumps are independent of each other, the bump pitch does not have to be the same as the pitch of the base recess. 【0069】 A solder bump formed on the electrode may be partially in contact with the electrode (metal electrode). Depending on the combination of materials, the electrode may have an alloy layer on its surface (at the interface between the solder bump and the electrode). 【0070】 The diameter of the alloy layer may be larger than the diameter of the solder bump in the planar direction. If the solder bumps are independent, the alloy layers formed beneath the solder bumps may be in contact with each other. 【0071】 In components with solder bumps, the height of the solder bump may be smaller than the diameter of the solder bump in the planar direction (direction of the electrode plane). The diameter of the solder bump in the planar direction is defined as the maximum diameter (maximum width) of the solder bump in the planar direction. The height of the solder bump is the height from the electrode surface to the top of the solder bump. By making the solder bump flat in this way, the contact area between the electrode on the opposing component and the solder bump increases when used in mounting, enabling a more stable connection. 【0072】 <Manufacturing method for components with solder bumps> A method for manufacturing a solder bump member comprises a preparation step of preparing a base body having a plurality of recesses having irregularities on its bottom surface; a placement step of arranging solder particles in the recesses; and a pressing step of pressing the base body and a substrate having electrodes with the solder particles and electrodes facing each other to bring the solder particles and electrodes into contact, thereby forming solder bumps on the electrodes having depressions on at least a part of the surface. 【0073】 A solder bump forming member is obtained through a preparation step and a placement step. The method for manufacturing a solder bump forming member can be said to include a preparation step of preparing a substrate having a plurality of recesses with irregularities on its bottom surface, and a placement step of placing solder particles in the recesses. 【0074】 The manufacturing method for the solder bump forming member 10 will be described with reference to Figures 3 to 6. According to the procedure described below, solder particles can be placed in the recesses of the prepared substrate by fusing the solder particles within the recesses. 【0075】 A substrate 60 for containing solder particles and solder particles are prepared. Figure 3(a) is a schematic plan view showing an example of the substrate 60, and Figure 3(b) is a cross-sectional view along the line Ib-Ib in Figure 3(a). The substrate 60 shown in Figure 3(a) has a plurality of recesses 62. The plurality of recesses 62 may be arranged regularly in a predetermined pattern. The position and number of the plurality of recesses 62 can be set according to the shape, size and pattern of the electrode to be connected. 【0076】 There are no particular restrictions on the distance L between adjacent recesses, but it can be 0.1 times or more the average particle diameter of the solder particles contained, and may be 0.2 times or more. The distance between recesses is not the distance between the centers of the recesses, but the distance from edge to edge of the recess opening. 【0077】 The recess 62 of the substrate 60 may be formed in a tapered shape, with the opening area increasing from the bottom surface 62a of the recess 62 toward the surface 60a of the substrate 60. That is, as shown in Figures 3(a) and 3(b), the width of the bottom surface 62a of the recess 62 (width a in Figures 3(a) and 3(b)) may be narrower than the width of the opening on the surface 60a of the recess 62 (width b in Figures 3(a) and 3(b)). The size of the recess 62 (width a, width b, volume, taper angle, depth, etc.) may be set according to the desired solder particle size. 【0078】 The shape of the recess 62 in the substrate 60 can be freely designed using lithography, machining, imprint technology, etc. Since the size of the solder particles 1 depends on the amount of solder fine particles 111 contained in the recess 62, the size of the solder particles 1 can be freely designed by designing the recess 62. 【0079】 The shape of the recess 62 may be other than the shapes shown in Figures 3(a) and 3(b). For example, the shape of the opening on the surface 60a of the recess 62 may be an ellipse, triangle, quadrilateral, polygon, etc., in addition to the circular shape shown in Figure 3(a). 【0080】 The shape of the recess 62 in a cross-section perpendicular to the surface 60a may be, for example, the shape shown in Figure 4. Figures 4(a) to (d) are schematic cross-sectional views showing examples of the cross-sectional shapes of recesses in the substrate. In all of the cross-sectional shapes shown in Figures 4(a) to (d), the width of the opening (width b) on the surface 60a of the recess 62 is the maximum width in the cross-sectional shape. This makes it easier to remove the solder particles formed in the recess 62, improving workability. Also, since the width of the opening (width b) is the maximum width in the cross-sectional shape, when transferring the solder particles 1 onto the electrode, the solder particles 1 can easily escape from the recess 62, and an improvement in the transfer rate can be expected. Furthermore, by appropriately adjusting the width of the opening (width b), misalignment when transferring the solder particles 1 onto the electrode becomes less likely, making it easier to form solder bumps in the correct position. 【0081】 The solder microparticles only need to include microparticles with a particle size smaller than the width (width b) of the opening on the surface 60a of the recess 62, but they may also contain a larger number of microparticles with a particle size smaller than width b. For example, the D10 particle size in the particle size distribution of the solder microparticles may be smaller than width b, the D30 particle size in the particle size distribution may be smaller than width b, and the D50 particle size in the particle size distribution may be smaller than width b. 【0082】 The particle size distribution of solder microparticles can be measured using various methods appropriate to the particle size. For example, methods such as dynamic light scattering, laser diffraction, centrifugal sedimentation, electrical detection band method, and resonant mass spectrometry can be used. Furthermore, methods for measuring particle size from images obtained by optical microscopes, electron microscopes, etc., can be used. Specific equipment includes flow-type particle image analyzers, microtrac, and Coulter counters. 【0083】 The CV value of the solder particles is not particularly limited, but a high CV value is desirable from the viewpoint of improving the filling of the recesses 62 by the combination of large and small particles. For example, the CV value of the solder particles may be greater than 20%, and may be 25% or more, or 30% or more. 【0084】 The CV value of solder microparticles is calculated by dividing the standard deviation of the particle size measured by the method described above by the average particle size (D50 particle size) and multiplying the result by 100. 【0085】 However, even solder microparticles with large variations in particle size distribution or irregular shapes can be used as raw materials if they can be contained within the recess 62. 【0086】 The solder particles may contain tin or a tin alloy. Examples of tin alloys that can be used include In-Sn alloy, In-Sn-Ag alloy, Sn-Au alloy, Sn-Bi alloy, Sn-Bi-Ag alloy, Sn-Ag-Cu alloy, Sn-Cu alloy, etc. Specific examples of these tin alloys are listed below. ·In-Sn (In52 mass%, Sn48 mass%, melting point 118℃) ·In-Sn-Ag (In20% by mass, Sn77.2% by mass, Ag2.8% by mass, melting point 175℃) • Sn-Bi (Sn 43% by mass, Bi 57% by mass, melting point 138°C) • Sn-Bi-Ag (Sn 42% by mass, Bi 57% by mass, Ag 1% by mass; melting point 139°C) • Sn-Ag-Cu (Sn 96.5% by mass, Ag 3% by mass, Cu 0.5% by mass; melting point 217°C) • Sn-Cu (Sn 99.3% by mass, Cu 0.7% by mass, melting point 227°C) ·Sn-Au (Sn21.0% by mass, Au79.0% by mass, melting point 278℃) 【0087】 The solder particles may contain indium or an indium alloy. Examples of indium alloys include In-Bi alloys and In-Ag alloys. Specific examples of these indium alloys are listed below. In-Bi (In 66.3% by mass, Bi 33.7% by mass, melting point 72°C) In-Bi (In 33.0% by mass, Bi 67.0% by mass, melting point 109°C) In-Ag (In 97.0% by mass, Ag 3.0% by mass, melting point 145℃) 【0088】 Depending on the application of the solder particles (temperature during use), the above-mentioned tin alloy or indium alloy can be selected. For example, if solder particles for use in low-temperature fusion bonding are desired, In-Sn alloy or Sn-Bi alloy can be used, and in this case, solder particles that can be fused at temperatures below 150°C can be obtained. If materials with high melting points, such as Sn-Ag-Cu alloy or Sn-Cu alloy, are used, solder particles that maintain high reliability even after being left at high temperatures can be obtained. 【0089】 The solder microparticles may contain one or more elements selected from Ag, Cu, Ni, Bi, Zn, Pd, Pb, Au, P, and B. Of these elements, Ag or Cu may be included from the following viewpoints. Specifically, the inclusion of Ag or Cu in the solder microparticles has the effect of lowering the melting point of the resulting solder particles to about 220°C, and obtaining solder particles with excellent bonding strength to electrodes, thereby achieving better conductivity reliability. 【0090】 The Cu content of the solder microparticles is, for example, 0.05 to 10 mass%, and may also be 0.1 to 5 mass% or 0.2 to 3 mass%. When the Cu content is 0.05 mass% or higher, solder particles capable of achieving good solder connection reliability are more easily obtained. Furthermore, when the Cu content is 10 mass% or lower, solder particles with a low melting point and excellent wettability are more easily obtained, resulting in better connection reliability of electrodes with solder bumps. 【0091】 The Ag content of the solder microparticles is, for example, 0.05 to 10 mass%, and may also be 0.1 to 5 mass% or 0.2 to 3 mass%. If the Ag content is 0.05 mass% or higher, solder particles capable of achieving good solder connection reliability are more easily obtained. Furthermore, if the Ag content is 10 mass% or lower, solder particles with a low melting point and excellent wettability are more easily obtained, resulting in better connection reliability of electrodes with solder bumps. 【0092】 The solder particles prepared as described above are placed in each of the recesses 62 of the substrate 60. Here, all of the solder particles may be placed in the recesses 62, or only a portion of the solder particles (for example, solder particles smaller than the width b of the opening of the recess 62) may be placed in the recesses 62. 【0093】 Figure 5 is a schematic cross-sectional view showing the state in which solder particles 111 are contained in the recesses 62 of the substrate 60. As shown in Figure 5, multiple solder particles 111 are contained in each of the multiple recesses 62. 【0094】 The degree to which the solder particles 1 protrude can be adjusted by adjusting the amount of solder fine particles 111 contained in the recess 62. The amount of solder fine particles 111 contained in the recess 62 may be, for example, 20% or more of the volume of the recess 62, and may also be 30% or more, 50% or more, or 60% or more. This allows some of the solder particles to protrude from the recess 62. In addition, variations in the amount contained are suppressed, and it becomes easier to obtain solder particles with a smaller particle size distribution. 【0095】 Generally, solder materials, when melted in an environment above their melting point, have the property of forming spherical shapes due to their own surface tension. 【0096】 The solder particles 111 contained in the recess 62 are brought together by a fusion process described later to form solder particles 1. When the height of the resulting solder particles 1 becomes greater than the depth of the recess 62, the solder particles 1 protrude from the recess 62. Therefore, if the diameter of the solder particles 1 is greater than the depth of the recess 62, the solder particles 1 will protrude from the recess 62. The diameter of the solder particles 1 can be adjusted by the shape of the recess 62 and the amount of solder particles 111 contained in the recess 62, thereby adjusting the degree of protrusion from the recess 62. 【0097】 When the solder particles 111 are melted by the fusion process described later, depending on the material of the recess 62, wetting spread occurs on the bottom surface and inner wall, and at least a portion of the solder particles 1 comes into contact with the bottom surface and / or inner wall of the recess 62. As a result, a flat portion may be formed on at least a portion of the solder particles 1. The size of this flat portion varies depending on the combination of the surface material of the recess 62 and the solder composition constituting the solder particles 111. Therefore, the shape of the solder particles 1 can be a perfect sphere, an ellipsoid, a flattened sphere, or a shape with a flat portion in part. As the substrate 60, inorganic materials such as glass and silicon, or organic materials such as plastics and resins can be used. Such materials generally tend to have low wettability with solder, and the solder particles 1 tend to be spherical in shape, close to a perfect sphere. Therefore, assuming that the solder particles 1 are spheres close to a perfect sphere, the height of the solder particles 1 can be approximated by the diameter of the solder particles 1. Since the diameter of the solder particle 1 can be calculated from the total volume of solder fine particles 111 filled in the recess 62, the amount of solder fine particles 111 required for the solder particle 1 to protrude from the recess 62 can be calculated. 【0098】 Assuming that all the solder microparticles 111 filling the recess 62 dissolve and coalesce to form solder particles 1, and that the solder particles 1 are spherical, it is possible to determine the amount of solder microparticles 111 required for the solder particles 1 to protrude from the recess 62. 【0099】 When the upper diameter (opening width b) of the recess 62 is L and the depth of the recess 62 is D, the aspect ratio of the recess is expressed as L / D. In this case, the filling rate of solder fine particles 111 into the recess 62 may be 66 volume% or more when the aspect ratio is 1, 38 volume% or more when the aspect ratio is 0.75, 17 volume% or more when the aspect ratio is 0.5, and 5 volume% or more when the aspect ratio is 0.25. 【0100】 To suppress variations in the amount of solder contained, the average particle size and particle size of the solder particles 111 can be selected according to the size of the recess 62 and the ratio of diameter to depth (aspect ratio). For example, if the diameter of the recess 62 is 4 μm and the depth is 4 μm (aspect ratio of 1), using solder particles 111 with an average particle size of 1 to 2 μm or less can suppress variations in the amount of solder filling the recess 62, suppress variations in the diameter of the resulting solder particles 1, and make it easier to suppress variations in the amount (height) of solder protrusion from the recess 62. When variations in the amount (height) of solder protrusion from the recess 62 are suppressed, when the solder particles 1 are pressed against the electrode, the contact between the solder particles 1 and the electrode becomes stable, and variations in solder bump formation are easily suppressed. 【0101】 The method for containing solder particles in the recess 62 is not particularly limited. The containment method may be dry or wet. For example, by placing solder particles on the substrate 60 and rubbing the surface 60a of the substrate 60 with a squeegee, excess solder particles can be removed while a sufficient amount of solder particles are contained in the recess 62. If the width b of the opening of the recess 62 is greater than the depth of the recess 62, solder particles may fly out of the opening of the recess 62. Using a squeegee removes solder particles that have flown out of the opening of the recess 62. Other methods for removing excess solder particles include blowing compressed air or rubbing the surface 60a of the substrate 60 with a nonwoven fabric or bundle of fibers. These methods use less physical force than a squeegee, making it easier to handle easily deformable solder particles. With these methods, it is also possible to leave solder particles that have flown out of the opening of the recess 62 inside the recess. 【0102】 Next, the solder fine particles 111 contained in the recess 62 are fused (for example, by heating to 130-260°C) to form solder particles 1 within the recess 62, some of which protrude from the recess 62. The solder fine particles 111 contained in the recess 62 coalesce upon melting and become spherical due to surface tension. At this time, at the contact point with the bottom surface 62a of the recess 62, the molten solder may follow the bottom surface 62a, forming a flat portion 11 on a part of the surface of the solder particles. In this way, the solder bump forming member 10 shown in Figure 1 is obtained. 【0103】 One method for melting the solder particles 111 contained in the recess 62 is to heat the solder particles 111 to a temperature above the melting point of the solder. However, due to the influence of the oxide film, the solder particles 111 may not melt or spread even when heated to a temperature above the melting point, and may not coalesce. Therefore, by exposing the solder particles 111 to a reducing atmosphere to remove the surface oxide film of the solder particles 111, and then heating them to a temperature above the melting point of the solder particles 111, the solder particles 111 can be melted, spread, and coalesced. The melting of the solder particles 111 may be carried out under a reducing atmosphere. By heating the solder particles 111 to a temperature above their melting point and using a reducing atmosphere, the oxide film on the surface of the solder particles 111 is reduced, making it easier for the melting, wetting, and coalescence of the solder particles 111 to proceed efficiently. 【0104】 The method for creating a reducing atmosphere is not particularly limited as long as it achieves the effects described above, and can include methods using hydrogen gas, hydrogen radicals, formic acid gas, etc. For example, by using a hydrogen reduction furnace, a hydrogen radical reduction furnace, a formic acid reduction furnace, or a conveyor furnace or continuous furnace thereof, solder fine particles 111 can be melted under a reducing atmosphere. These devices may be equipped with a heating device, a chamber filled with an inert gas (nitrogen, argon, etc.), a mechanism for creating a vacuum inside the chamber, etc., which makes it easier to control the reducing gas. Furthermore, if the inside of the chamber can be vacuumed, voids can be removed by reduced pressure after the melting and coalescence of the solder fine particles 111, and solder particles 1 with even better connection stability can be obtained. 【0105】 The profile of the reduction and dissolution conditions, temperature, and furnace atmosphere adjustment for the solder fine particles 111 may be appropriately set considering the melting point, particle size, recess size, and material of the substrate 60 of the solder fine particles 111. For example, solder particles can be obtained as follows. A substrate 60 with solder particles 111 filling the recesses is inserted into the furnace and a vacuum is applied. A reducing gas is introduced to fill the furnace with the reducing gas and remove the surface oxide film of the solder particles 111. Reducing gases are removed by vacuuming. The solder particles 111 are heated above their melting point to dissolve and coalesce, forming solder particles within the recesses 62. After filling the furnace with nitrogen gas, the internal temperature is returned to room temperature to obtain solder particles 1. 【0106】 Alternatively, solder particles may be obtained, for example, as follows. The following method has the advantage that heating the solder particles in a reducing atmosphere increases their reducing power, making it easier to remove the surface oxide film of the solder particles. A substrate 60 with solder particles 111 filling the recesses is inserted into the furnace and a vacuum is applied. A reducing gas is introduced to fill the furnace with it. The solder particles 111 are heated by a furnace heating heater to remove the surface oxide film of the solder particles 111. Reducing gases are removed by vacuuming. The solder particles 111 are heated above their melting point to dissolve and coalesce, forming solder particles within the recesses 62. After filling the furnace with nitrogen gas, the internal temperature is returned to room temperature to obtain solder particles 1. 【0107】 Furthermore, solder particles may be obtained, for example, as follows. The following method has the advantage of being able to be processed in a short time because the furnace temperature only needs to be adjusted once each for raising and lowering. A substrate 60 with solder particles 111 filling the recesses is inserted into the furnace and a vacuum is applied. A reducing gas is introduced to fill the furnace with it. The solder particles 111 are heated above their melting point by a furnace heating heater to remove the surface oxide film of the solder particles 111 by reduction. At the same time, the solder particles are dissolved and coalesced to form solder particles in the recesses 62. Vacuuming removes reducing gases and further reduces voids within the solder particles. After filling the furnace with nitrogen gas, the internal temperature is returned to room temperature to obtain solder particles 1. 【0108】 After forming solder particles in the recess 62 described above, a step may be added to create a reducing atmosphere inside the furnace again to remove any remaining surface oxide film. This reduces residue such as solder fine particles that remained unfused and parts of the oxide film that remained unfused. 【0109】 When using an atmospheric pressure conveyor furnace, the substrate 60, in which solder fine particles 111 are filled in the recesses, can be placed on a conveyor belt and passed through multiple zones in succession to obtain solder particles 1. For example, solder particles can be obtained as follows. The substrate 60, in which solder particles 111 are filled into the recesses, is placed on a conveyor set to a constant speed. The solder particles 111 are passed through a zone filled with an inert gas such as nitrogen or argon at a temperature lower than the melting point of the solder particles. The surface oxide film of the solder particles 111 is removed by passing them through a zone where a reducing gas such as formic acid gas, which is at a temperature lower than the melting point of the solder particles 111, is present. The solder particles 111 are melted and coalesced by passing them through a zone filled with an inert gas such as nitrogen or argon at a temperature above the melting point of the solder particles 111. Solder particles 1 can be obtained by passing them through a cooling zone filled with an inert gas such as nitrogen or argon. 【0110】 Alternatively, solder particles may be obtained using an atmospheric pressure conveyor furnace in the following manner. The substrate 60, in which solder particles 111 are filled into the recesses, is placed on a conveyor set to a constant speed. The solder particles 111 are passed through a zone filled with an inert gas such as nitrogen or argon at a temperature above their melting point. The solder particles 111 are passed through a zone containing a reducing gas such as formic acid gas at a temperature above the melting point of the solder particles 111 to remove the surface oxide film of the solder particles 111. At the same time, the solder particles are melted and coalesced. Solder particles 1 can be obtained by passing them through a cooling zone filled with an inert gas such as nitrogen or argon. 【0111】 Because conveyor furnaces can process materials at atmospheric pressure, they can also continuously process film-like materials using a roll-to-roll method. For example, solder microparticles can be fused in the following way. A continuous roll of substrate 60 is manufactured, in which solder fine particles 111 are filled into the recesses. A roll unwinding machine is installed on the inlet side of the conveyor furnace, and a roll winding machine is installed on the outlet side of the conveyor furnace, to transport the base body 60 at a constant speed. By passing the solder through each zone in the conveyor furnace, the solder particles 111 filled in the recesses can be fused together. 【0112】 The above method makes it possible to form solder particles 1 of uniform size regardless of the material and shape of the solder microparticles 111. For example, indium-based solder can be deposited by plating, but it is difficult to deposit it in particulate form, and it is also difficult to handle because it is soft. However, the above method makes it possible to easily manufacture indium-based solder particles with a uniform particle size by using indium-based solder microparticles as a raw material. Furthermore, the formed solder particles 1 can be handled while contained in the recesses 62 of the substrate 60. Therefore, the solder particles 1 can be transported and stored without deformation. Moreover, since the formed solder particles 1 are contained in the recesses 62 of the substrate 60, they can be brought into contact with an electrode without deformation. 【0113】 In the above method, solder fine particles 111 are fused in the recess 62 of the substrate 60 and solder particles 1 are placed in the recess 62. However, a solder bump forming member may also be obtained by placing separately prepared solder particles, such as solder particles produced by the above method that have been removed from the recess and stored, or solder particles purchased as industrial products with a desired particle size distribution, into the substrate recess. 【0114】 As a method for housing separately prepared solder particles into the substrate recesses, for example, the above method of housing solder fine particles into the recesses can be used. 【0115】 Next, we will describe the process of preparing a solder bump-equipped component by pressing the solder bump-forming component prepared as described above onto the electrode. 【0116】 Specific examples of substrates (circuit components) having multiple electrodes on their surface include chip components such as IC chips (semiconductor chips), resistor chips, capacitor chips, and driver ICs; and rigid package substrates. Generally, these circuit components have a large number of circuit electrodes. Other examples of substrates having multiple electrodes on their surface include flexible tape substrates with metal wiring, flexible printed circuit boards, and wiring substrates such as glass substrates with indium tin oxide (ITO) deposited on them. 【0117】 Examples of electrodes include those made of copper, copper / nickel, copper / nickel / gold, copper / nickel / palladium, copper / nickel / palladium / gold, copper / nickel / gold, copper / palladium, copper / palladium / gold, copper / tin, copper / silver, indium tin oxide, etc. Electrodes can be formed by electroless plating, electrolytic plating, sputtering, etching of metal foil, etc. 【0118】 Figures 6(a) and 6(b) are schematic cross-sectional views illustrating an example of the manufacturing process of a solder bump-equipped member (solder bump-equipped electrode substrate). In Figure 6(a), the substrate 60 has a bottom surface with a recess 62 in which one solder particle 1 is contained in each recess. On the other hand, the substrate 2 has multiple electrodes 3 on its surface. The surface of the substrate 2 on the electrode 3 side is placed opposite the surface of the substrate 60 on the opening side of the recess 62, and the substrate 60 and the substrate 2 are pressed together until the solder particle 1 contained in the recess 62 of the substrate 60 comes into contact with the electrode 3 (arrows A and B in Figure 6(a)). From the viewpoint of suitably joining the solder particle 1 and the electrode 3, pressing means pressing the solder bump-forming member 10 and the substrate 2 together with a force of about 0.1 to 600 MPa in the directions of arrows A and B in Figure 6(a). This makes it possible to form solder bumps on the electrodes that have depressions in at least a part of the surface. Figure 6(b) is a schematic diagram of the solder bump member 20 obtained in this manner. There is no particular limit to the number of solder particles 1 that come into contact with each electrode 3; there may be one particle per electrode, or multiple particles per electrode. Alternatively, the solder particles 1 may come into contact with only specific electrodes among the multiple electrodes. Because the force acting between the solder particles 1 and the recess 62 (for example, an intermolecular force such as the van der Waals force) is greater than the gravitational force acting on the solder particles 1, the solder particles 1 remain in the recess 62 without falling out, even when the main surface of the substrate 60 is facing downwards. Furthermore, if at least a portion of the solder particles 1 has a flat portion that comes into contact with the bottom surface and / or inner wall of the recess 62, the solder particles 1 are less likely to fall out of the recess 62. 【0119】 Alignment marks on the surfaces of both the base and the substrate make it easier to align them. For example, when the solder bump forming member and the electrode-equipped substrate are placed facing each other, alignment marks can be pre-placed on the surfaces of the base and the substrate so that the positions of the recesses and the electrodes are relative. Then, when actually placing the solder bump forming member and the electrode-equipped substrate facing each other, the alignment marks can be used to adjust the position, allowing for the formation of solder bumps on the electrodes with high positional accuracy. 【0120】 In the pressing process, a base body 60 may be pressed onto a substrate 2 that has been pre-coated with a resin material, flux material, etc., that has tack force, to form solder bumps. In this case, the solder particles 1 are transferred onto the electrode 3, and a solder bumped member can be obtained in which the solder bump 1A and the electrode 3 are not metal-jointed. By manufacturing a connecting structure using such a solder bumped member, electrode-to-electrode joining can be performed more favorably. The solder bumps melt due to heating during the manufacturing of the connecting structure, and the upper and lower electrodes are joined together. 【0121】 In the pressing process, from the viewpoint of more favorably bonding the solder particles and the electrode, the solder particles may be heated while the solder particles and the electrode are in contact under pressure. From the viewpoint of shortening manufacturing time, the solder particles may be heated to a temperature above their melting point during the pressing process. Heating the solder particles above their melting point causes them to melt, allowing for efficient and quick bonding with the electrode surface. Furthermore, heating the solder particles above their melting point increases their fluidity, making it easier for them to contact the electrode surface and increasing the reliability of the bonding. Specifically, for example, when bonding solder particles to multiple electrodes at once, the number of unbonded electrodes can be reduced, thereby increasing the yield. Additionally, the increased reliability of the bonding between the solder particles and the electrodes allows for a reduction in the pressing time. Furthermore, from the viewpoint of making the bonding between solder particles and electrodes more uniform, the solder particles may be heated to a temperature below their melting point during the pressing process. When solder particles are heated to a temperature below their melting point, the solder particles do not melt, but mutual diffusion occurs between the metal elements in the solder particles and the metal elements in the electrodes at the contact surface between the solder particles and the electrodes, causing them to bond. By heating the temperature below the melting point, this mutual diffusion occurs slowly, making it easier to maintain the solder composition even when heated for a long time (e.g., 10 minutes or more). Specifically, when bonding solder particles to multiple electrodes at once, even in situations where bonding is likely to be uneven due to pressure unevenness, variations in electrode surface height, etc., the bonding between solder particles and electrodes can be made more reliable by setting a longer pressing time to mitigate pressure unevenness. 【0122】 Solder particles 1 may not melt or spread even when heated due to the influence of an oxide film. For this reason, the solder particles 1 can be melted by exposing them to a reducing atmosphere to remove the surface oxide film of the solder particles 1, and then heating the solder particles 1. Furthermore, the melting of the solder particles 1 can be carried out in a reducing atmosphere. By heating the solder particles 1 and creating a reducing atmosphere, the oxide film on the surface of the solder particles 1 is reduced, and further, the oxide film on the electrode surface is reduced, making it easier for the melting and spreading of the solder particles 1 to proceed efficiently. In other words, the manufacturing method of a solder bump member may further include a reduction step in which the solder particles (and / or electrodes) are exposed to a reducing atmosphere before the placement step, or after the placement step but before the pressing step. Also, in the pressing step of the manufacturing method of a solder bump member, the solder particles may be heated in a reducing atmosphere. In the pressing process for forming solder bumps on electrodes, the electrode and the opening surface of the solder bump forming member are brought into close contact (while heating as necessary), so that solder bumps are formed only on the electrode, and solder bridging between adjacent electrodes is easily suppressed. 【0123】 For details regarding the reducing atmosphere, refer to the description of the manufacturing method for solder bump forming components as appropriate. 【0124】 If heating is performed during the pressing process, the solder bump 1A formed by the melted solder particles 1 is fixed to the electrode 3 by cooling the entire assembly after heating. 【0125】 After the solder bumps 1A are formed on the electrode 3, the solder bump-forming member 10 can be removed from the substrate 2 to obtain the solder bump-attached member 20. In other words, the method for manufacturing the solder bump-attached member may further include a removal step after the pressing step in which the base material is removed from the substrate. 【0126】 On the resulting solder bump member 20, there may be solder particles 1 that have detached from the recesses 62 but are not used for bonding with the electrodes 3. Therefore, the manufacturing method of the solder bump member may further include a cleaning step to remove solder particles that are not bonded to the electrodes. Examples of cleaning methods include blowing compressed air or rubbing the substrate surface with a nonwoven fabric or bundle of fibers. 【0127】 According to the method for manufacturing a solder bump member, a solder bump member 20 can be obtained, comprising a substrate 2, an electrode 3, and a solder bump 1A in that order, with a depression formed on at least a portion of the solder bump surface. 【0128】 <Method for manufacturing a connecting structure> Figures 7(a) and 7(b) are schematic cross-sectional views illustrating an example of the manufacturing process of a connecting structure. The manufacturing method of the connecting structure will be explained with reference to Figures 7(a) and 7(b). First, a solder bump member 20 shown in Figure 6(b) is prepared in advance. Another substrate 4 having multiple other electrodes 5 is also prepared. The two are then placed so that the solder bump 1A and the other electrodes 5 face each other. Subsequently, by heating while the solder bump 1A and the other electrodes 5 are in contact, the solder bump 1A melts between electrode 3 and the other electrodes 5. After that, by cooling the entire assembly, a solder layer 1B is formed between electrode 3 and the other electrodes 5, and the electrodes are electrically connected. At this time, heating in an atmosphere that blocks oxygen can suppress oxidation of the solder bump 1A and electrode 5. For example, heating in an inert gas atmosphere such as nitrogen can be used, and specifically, a vacuum reflow oven, a nitrogen reflow oven, etc., can be used. 【0129】 To melt the solder bump 1A by heating and more favorably join the opposing electrodes 3 and 5, heating can be performed under a reducing atmosphere. Hydrogen gas, hydrogen radicals, formic acid, etc., can be used to create a reducing atmosphere. Specifically, hydrogen reduction furnaces, hydrogen reflow furnaces, hydrogen radical furnaces, formic acid furnaces, and their vacuum furnaces, continuous furnaces, and conveyor furnaces can be used. By creating a reducing atmosphere, the oxide film on the surface of the solder bump 1A and the oxide film on the surface of the electrode 5 can be reduced and removed, so that the solder bump 1A can easily wet and spread onto the electrode 5, and a more stable bond can be achieved between the electrode 3 and the electrode 5 via the solder layer 1B. 【0130】 Pressure may be applied to ensure a stable connection. A solder bump member 20, as shown in Figure 6(b), is prepared in advance. Another substrate 4 having multiple other electrodes 5 on its surface is also prepared. The two are then positioned so that the solder bump 1A and the other electrodes 5 face each other. Then, pressure is applied in the thickness direction of the laminate of these members (in the direction of arrows A and B shown in Figure 7(a)). By heating the entire assembly during the pressurization process, the solder bump 1A melts between electrode 3 and the other electrodes 5. After that, by cooling the entire assembly, a solder layer 1B is formed between electrode 3 and the other electrodes 5, and the electrodes are electrically connected. In this case as well, in order to suppress oxidation of the solder bump 1A, electrode 5, and electrode 3 surfaces, the above process may be performed under vacuum, under an inert gas atmosphere such as nitrogen, or under a reducing atmosphere. Methods for creating a reducing atmosphere include the aforementioned hydrogen gas, hydrogen radicals, formic acid, etc. Specifically, hydrogen reduction furnaces, hydrogen reflow furnaces, hydrogen radical furnaces, formic acid furnaces, vacuum furnaces, continuous furnaces, conveyor furnaces, etc., can be used. 【0131】 A reducing flux material can be placed near the solder bump 1A or near electrodes 5 and 3. First, a member 20 with solder bumps, as shown in Figure 6(b), is prepared in advance. The flux material is placed on the entire surface of member 20 where the solder bump 1A is formed, or near the solder bump 1A and the electrode 3 including the solder bump 1A. Another substrate 4 having multiple other electrodes 5 on its surface is also prepared. The two are then placed so that the solder bump 1A and the other electrodes 5 face each other. Subsequently, by heating the solder bump 1A and the other electrodes 5 while they are in contact, for example, via the flux material, the solder bump 1A melts between electrode 3 and the other electrodes 5. After that, by cooling the whole, a solder layer 1B is formed between electrode 3 and the other electrodes 5, and the electrodes are electrically connected. After that, by washing away the flux components, corrosion of the solder layer 1B and electrodes 3 and 5 can be suppressed by the flux residue. 【0132】 Alternatively, a solder bump member 20, as shown in Figure 6(b), can be prepared in advance. Another substrate 4 having multiple other electrodes 5 on its surface is also prepared, and flux material is placed on the entire surface of the substrate 4 with electrodes 5, or near the surface of electrodes 5. The two are then positioned so that the solder bump 1A and the other electrodes 5 face each other. Subsequently, the solder bump 1A and the other electrodes 5 are heated, for example, while in contact via the flux material, causing the solder bump 1A to melt between electrode 3 and the other electrodes 5. After that, the entire assembly is cooled, forming a solder layer 1B between electrode 3 and the other electrodes 5, and electrically connecting the electrodes. 【0133】 In all of the above methods, the flux material is trapped in the depressions on the surface of the solder bump, and a sufficient amount of flux is secured to bond the solder bump to the electrode. 【0134】 Heating methods for melting solder bumps 1A include, under vacuum, heating a heating plate in a reflow oven and transferring the heat to solder bumps 1A via substrates 2 and 4 in contact with the heating plate, and using radiation such as infrared rays. In addition to, or in combination with, heating methods using a heating plate or infrared rays, a method of heating solder bumps 1A via heated gases and gases can be used. Specifically, solder bumps 1A can be heated by heating an inert gas such as nitrogen, hydrogen, hydrogen radicals, formic acid, etc. The flux material may include at least one selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, benzoic acid, and malic acid. 【0135】 Another method involves using electromagnetic waves such as microwaves. For example, specific electromagnetic waves can be applied externally to heat the components of electrode 3, electrode 5, and solder bump 1A. For instance, if substrates 4 and 2 are resin substrates, irradiating them with specific electromagnetic waves from the outside allows the waves to penetrate substrates 4 and 2, heating electrode 3 and solder bump 1A or electrode 5. This method has the advantage of selectively heating the parts to be joined, thus avoiding unnecessary thermal history. For example, even if substrates 2 and 4 are made of materials with low heat resistance, the solder bump 1A can be melted to reliably join electrode 3 and electrode 5. Furthermore, since less thermal history remains in the entire joining system, it has the advantage of easily suppressing warping and decomposition after joining. When using microwaves, solder bump 1A can be melted in a shorter time than when using heating plates, infrared rays, or heating gases, thus reducing the thermal history in the entire joining system and making it easier to obtain the aforementioned effects. Furthermore, using microwaves allows for localized heating of only the parts of electrode 3, solder bump 1A, and electrode 5 that are to be joined or melted. Therefore, it is not necessary to heat the entire system, and even if materials with low heat resistance or other electronic components that should not be heated are located near electrode 3 and electrode 5, the solder bump 1A can be melted and joined. 【0136】 Another method involves using ultrasound. For example, by placing an ultrasonic transducer on the opposite side of electrode 3 on substrate 2 and applying ultrasound, the solder bump 1A melts due to the vibrational energy of the ultrasound. This joins electrode 3 and electrode 5, which was previously placed opposite electrode 3, via the solder layer 1B. Because ultrasonic joining can melt solder bump 1A in a short time, there is no need to heat the entire substrate 2 and substrate 4, and electrodes 3 and 5 can be reliably joined even if substrate 2 and substrate 4 are made of materials with low heat resistance. 【0137】 Figure 7(b) is a schematic diagram of the connection structure 30 obtained in this manner. Specifically, Figure 7(b) schematically shows a state in which an electrode 3 on substrate 2 and another electrode 5 on another substrate 4 are connected via a solder layer 1B formed by fusion bonding. In this specification, "fusion bonding" means a state in which at least a part of the electrodes is joined by solder (solder bump 1A) that has been melted by heat, and then the solder is bonded to the surface of the electrodes through a solidification process. The connection structure 30 can be said to include a first circuit member having a substrate and a plurality of electrodes on its surface, a second circuit member having another substrate and a plurality of other electrodes on its surface, and a solder layer between the plurality of electrodes and the plurality of other electrodes. From the viewpoint of maintaining the strength of the connection structure and blocking deterioration factors (moisture, oxygen, etc.) of the connection part, the parts between the circuit members may be sealed by methods such as mold underfill, capillary underfill, or edge bonding. For example, the space between the first circuit member and the second circuit member can be filled with an underfill material mainly composed of epoxy resin. 【0138】 Applications of connection structures include connection parts for semiconductor memory and semiconductor logic chips, connection parts for primary and secondary mounting of semiconductor packages, junctions for CMOS image elements, laser elements, LED light-emitting elements, and devices using these such as cameras, sensors, liquid crystal displays, personal computers, mobile phones, smartphones, and tablets. 【0139】 The details of this embodiment are listed below. A method for manufacturing a member with solder bumps, comprising: a preparation step of preparing a base body having a plurality of recesses having irregularities on its bottom surface; a placement step of arranging solder particles in the recesses; and a pressing step of pressing the base body and a substrate having electrodes with the solder particles and electrodes facing each other to bring the solder particles and electrodes into contact, thereby forming solder bumps on the electrodes having depressions in at least a part of the surface. The above manufacturing method, wherein solder particles are heated during the pressing process. The above manufacturing method further comprises a reduction step of exposing solder particles to a reducing atmosphere before the placement step. The manufacturing method described above, further comprising a reduction step of exposing solder particles to a reducing atmosphere after the placement step and before the pressing step. The above manufacturing method, wherein solder particles are heated in a reducing atmosphere during the pressing process. The above manufacturing method further comprises a removal step of removing the substrate from the substrate after the pressing step. The above manufacturing method further comprises a cleaning step to remove solder particles that are not bonded to the electrodes after the removal step. A solder bump member comprising a substrate having electrodes and solder bumps on the electrodes, wherein a recess is formed on at least a portion of the surface of the solder bump. The above-mentioned component with solder bumps, wherein the depth of the solder bump recess is 25% or less of the height of the solder bump. The above-mentioned component with solder bumps, where adjacent solder bumps are independent of each other. The above-described component with solder bumps, wherein the height of the solder bump is smaller than the diameter of the solder bump in the planar direction. A solder bump forming member comprising a base body having multiple recesses with uneven surfaces on its bottom surface, and solder particles within the recesses. The solder bump forming member described above, wherein the height difference between the recessed and raised parts of the uneven surface is 20% or less of the average particle diameter of the solder particles. The solder bump forming member described above, wherein the average particle size of the solder particles is 1 to 35 μm and the CV value is 20% or less. [Examples] 【0140】 The embodiments will be described in more detail below with reference to examples, but the embodiments are not limited to these examples. 【0141】 <Fabrication of bump-forming components> (Example 1) Process a1: Classification of solder particles 100g of Sn-Bi solder microparticles (manufactured by 5N Plus, melting point 139°C, Type 8) were immersed in distilled water, ultrasonically dispersed, and then allowed to stand. The solder microparticles suspended in the supernatant were collected. This procedure was repeated to collect 10g of solder microparticles. The average particle size of the obtained solder microparticles was 1.0 μm, and the CV value was 42%. Step b1: Placement onto the substrate As shown in Table 1, a substrate 1 (polyimide film, 100 μm thick) was prepared, having an aperture diameter of 6.2 μm, a base diameter of 4.8 μm, a depth of 3.7 μm, and multiple recesses with a base surface unevenness (height difference between recesses and protrusions, formed by dry etching) of 0.4 μm. The multiple recesses were arranged regularly at a pitch of 6.4 μm. Solder microparticles (average particle size 1.0 μm, CV value 42%) obtained in step a1 were placed in the recesses of substrate 1. Excess solder microparticles were removed by rubbing the side of substrate 1 where the recesses were formed with a micro-sticky roller, so that the solder microparticles were placed only within the recesses. Step c1: Solder particle formation In step b1, the substrate 1, in which solder particles were placed in the recesses, was placed in a hydrogen radical reduction furnace (Shinko Seiki Co., Ltd., plasma reflow apparatus). After vacuuming, hydrogen gas was introduced into the furnace to fill it with hydrogen gas. The furnace temperature was then adjusted to 120°C, and hydrogen radicals were irradiated for 5 minutes. After that, the hydrogen gas in the furnace was removed by vacuuming, and the furnace was heated to 170°C. Nitrogen was then introduced into the furnace to return it to atmospheric pressure, and the temperature inside the furnace was lowered to room temperature to form solder particles. As a result, a solder bump forming member (film) having solder particles in the recesses was obtained. 【0142】 [Table 1] 【0143】 <Evaluation of solder particles> A portion of the solder bump-forming material obtained through process c1 was fixed to the surface of a scanning electron microscope (SEM) observation base, and platinum sputtering was applied to the surface. The diameter of 300 solder particles was measured using the SEM, and the average particle diameter was calculated. The results are shown in Table 2. In addition, the surface shape of a portion of the solder bump-forming material obtained through process c1 was measured using a laser microscope (Olympus Corporation, LEXT OLS5000-SAF), and the height of the solder particles from the substrate surface was measured, and the average value of 300 particles was calculated. The results are shown in Table 2. 【0144】 (Examples 2-4) Except for changing the size of the recesses as shown in Table 1, a substrate with solder particles held in the recesses was fabricated in the same manner as in Fabrication Example 1 and evaluated. The results are shown in Table 2. 【0145】 [Table 2] 【0146】 <Fabrication of evaluation chips with solder bumps> Process d1: Preparation of evaluation chip We prepared four types of gold-tipped nail tips (5 x 5 mm, thickness: 0.5 mm) as shown below. Chip C1…Electrode size: 24μm × 12μm, Pitch: 48μm in the X direction, 24μm in the Y direction, Number of bumps: 15,000 Chip C2… Electrode size: 72μm × 36μm, Pitch: 144μm in the X direction, 72μm in the Y direction, Number of bumps: 3400 Chip C3… Electrode size: 96μm × 48μm, Pitch: 192μm in the X direction, 96μm in the Y direction, Number of bumps: 850 Chip C4… Electrode size: 140μm × 70μm, Pitch: 280μm in the X direction, 140μm in the Y direction, Number of bumps: 420 【0147】 Step e1: Solder bump formation Following the procedures i) to ii) shown below, solder bumps were formed on the chip C1 prepared in step d1 using the solder bump forming member 1 manufactured in step c1. i) A glass plate (0.3 mm thick) was placed on the lower heating plate of a formic acid reflow oven (manufactured by Shinko Seiki Co., Ltd., batch-type vacuum soldering equipment), and the evaluation chip C1 was positioned on the glass plate with the Au electrode facing upwards. A solder bump forming component 1, adjusted to a size of 7 x 7 mm, was placed on the evaluation chip C1 with the recessed opening facing the Au electrode. A glass plate (0.3 mm thick) and a SUS weight were then placed on top of it in that order. ii) After vacuuming, formic acid gas was filled, the lower heating plate was heated to 150°C, and heated for 1 minute. Subsequently, after removing the formic acid gas by vacuuming, nitrogen purging was performed, the lower heating plate was returned to room temperature, the furnace was opened to the atmosphere, and solder particles were transferred onto the electrodes of the evaluation chip C1 to form solder bumps. This resulted in an evaluation chip with solder bumps (a component with solder bumps). A depression of a predetermined depth was formed at the top of the solder bumps. 【0148】 <Evaluation of evaluation chips with solder bumps> The height and diameter of the solder bumps on the evaluation chip obtained after process e1, and the depth of the depression at the top of the solder bumps were measured using a laser microscope (Olympus Corporation, LEXT OLS5000-SAF), and the average value of 300 samples was calculated. The results are shown in Table 3. 【0149】 [Table 3] 【0150】 (Examples 2-4) Solder bump formation was performed in the same manner as in process e1, except that solder bump forming members 2-4 and evaluation chips C2-C4 were used. Furthermore, 300 solder bumps on the electrode were evaluated, and the height and diameter of the solder bumps, as well as the average depth of the depression at the top of the solder bumps, were calculated. The results are shown in Table 3. 【0151】 Figure 8 is an SEM image of the solder bump forming member obtained by fabrication example 1. It can be seen that a depression is formed at the top of the solder bump. 【0152】 <Fabrication of connecting structures> Process f1: Preparation of the evaluation board Four types of evaluation boards with gold bumps (70 x 25 mm, thickness: 0.5 mm) were prepared, as shown below. These gold bumps are positioned opposite the gold electrodes of the aforementioned evaluation chips C1 to C4, and alignment marks are provided on the boards. In addition, lead wires for resistance measurement are formed on some of the gold bumps. Substrate D1: Area 24μm × 12μm, Pitch: 48μm in the X direction, 24μm in the Y direction, Height: 3μm, Number of bumps: 15,000 Substrate D2: Area 72μm × 36μm, Pitch: 144μm in the X direction, 72μm in the Y direction, Height: 3μm, Number of bumps: 3400 Substrate D3: Area 96μm x 48μm, Pitch: 192μm in the X direction, 96μm in the Y direction, Height: 3μm, Number of bumps: 850 Substrate D4: Area 140μm × 70μm, Pitch: 280μm in the X direction, 140μm in the Y direction, Height: 3μm, Number of bumps: 420 【0153】 Step g1: Electrode bonding Following the procedures i) to iv) shown below, the evaluation chip with solder bumps fabricated in step e1 and the evaluation board with gold bumps prepared in step f1 were connected via solder bumps. i) The gold bumped evaluation substrate D1 was fixed onto the stage of a spin coater SC-308S (manufactured by Oshikane Co., Ltd.) using polyimide tape. A total of 9.6 g of liquid flux WHS-003C (manufactured by Arakawa Chemical Industries, Ltd.) was dropped one drop at 1 cm intervals, and then the stage was rotated in a two-stage process of 500 rpm for 10 seconds and 1000 rpm for 3 seconds to obtain a gold bumped evaluation substrate D1 with a uniform coating of liquid flux. The thickness of the flux layer measured after natural drying was 1 μm or less. ii) An evaluation substrate D1 with flux-coated gold bumps was placed on the stage of the FC3000W (manufactured by Toray Engineering Co., Ltd.), an evaluation chip C1 with solder bumps was picked up by the head, and the gold electrodes were aligned using alignment marks, and the evaluation chip C1 with solder bumps was placed on the evaluation substrate D1 with flux-coated gold bumps. Then, while pressing the two with a tool, a bonded sample 1 was obtained by heating and pressing them together for 6 seconds at a tool temperature of 220°C. iii) The flux remaining between the evaluation chip and the evaluation substrate was removed by washing the bonded sample 1 with isopropyl alcohol. iv) An appropriate amount of viscosity-adjusted underfill material (Hitachi Chemical Co., Ltd., CEL series) was placed between the evaluation chip of bonding sample 1, from which residual flux had been removed, and the evaluation substrate. After filling under vacuum, the material was cured at 125°C for 4 hours to fabricate the connection structure 1 between the evaluation chip and the evaluation substrate. 【0154】 (Examples 2-4) Except for using evaluation chips C2-4 with solder bumps and evaluation substrates D2-4 with gold bumps, the connecting structures 2-4 were fabricated in the same manner as in process g1. The combinations of materials used to fabricate the connecting structures are as follows. Connection structure (1): Chip C1 / Solder bump forming member 1 / Substrate D1 Connection structure (2): Chip C2 / Solder bump forming member 2 / Substrate D2 Connection structure (3): Chip C3 / Solder bump forming member 3 / Substrate D3 Connection structure (4): Chip C4 / Solder bump forming member 4 / Substrate D4 【0155】 <Evaluation of connection structures> Continuity resistance tests and insulation resistance tests were performed on some of the obtained connection structures. The results are shown in Tables 4, 5, and 6. 【0156】 (Continuity resistance test - Moisture absorption and heat resistance test) Regarding the conductivity resistance between gold-bumped chips and gold-bumped substrates, the initial conductivity resistance and the values ​​after moisture absorption and heat resistance tests (left for 100, 500, and 1000 hours at 85°C and 85% humidity) were measured for 20 samples, and the average value was calculated. The conductivity resistance was evaluated from the obtained average value according to the following criteria. The results are shown in Table 4. Note that if the conductivity resistance meets either criterion A or B below after 1000 hours of moisture absorption and heat resistance testing, it can be said that the conductivity resistance is good. A: The average conductivity resistance is less than 2Ω. B: Average conductivity value is 2Ω or more but less than 5Ω C: Average conductivity value is 5Ω or more but less than 10Ω D: Average conductivity value is between 10Ω and 20Ω E: Average conductivity of 20Ω or more 【0157】 (Continuity resistance test - High-temperature storage test) Regarding the conductivity resistance between gold-bumped chips (bumps) and gold-bumped substrates (bumps), the initial conductivity resistance and the values ​​after high-temperature storage tests (100, 500, and 1000 hours at 100°C) were measured for 20 samples. After high-temperature storage, a drop impact was applied, and the conductivity resistance of the samples after the drop impact was measured. The drop impact was induced by screwing the connecting structure to a metal plate and dropping it from a height of 50 cm. After the drop, the DC resistance value was measured at the solder joint (4 locations) of the chip corner that received the greatest impact, and fracture was considered to have occurred when the measured value increased by more than 5 times from the initial resistance. A total of 80 measurements were taken at 4 locations for each sample. The results are shown in Table 5. Solder connection reliability was evaluated as good if the following criteria A or B were met after 20 drops. A: There were 0 locations where fractures occurred. B: There were between one and five fracture locations. C: There were between 6 and 20 fracture locations. D: There were 21 or more fracture locations. 【0158】 (Insulation resistance test) Regarding the insulation resistance between chip electrodes, the initial value of the insulation resistance and the value after migration tests (left for 100, 500, and 1000 hours under conditions of 60°C, 90% humidity, and 20V application) were measured for 20 samples. Of the 20 samples, 10 had an insulation resistance value that was within the range of 20. 9 The percentage of samples with a resistance of Ω or greater was calculated. The insulation resistance was evaluated from the obtained percentage according to the following criteria. The results are shown in Table 6. Note that if the sample meets either criterion A or B below after 1000 hours of migration testing, the insulation resistance can be considered good. A: Insulation resistance value 10 9 The percentage of those with a value of Ω or higher is 100% B: Insulation resistance value 10 9 The percentage of those with a score of Ω or higher is between 90% and 100%. C: Insulation resistance value 10 9 The percentage of those with a score of Ω or higher is between 80% and 90%. D: Insulation resistance value 10 9 The percentage of those with a score of Ω or higher is between 50% and 80%. E: Insulation resistance value 10 9 The percentage of those with a score of Ω or higher is less than 50%. 【0159】 [Table 4] 【0160】 [Table 5] 【0161】 [Table 6] [Explanation of symbols] 【0162】 1...solder particles, 1A...solder bump, 1B...solder layer, 2...substrate, 3...electrode, 4...other substrate, 5...other electrode, 10...solder bump forming member, 20...member with solder bump, 30...connecting structure, 60...base, 62...recess, 111...solder fine particles, 600...base, 601...base layer, 602...recess layer.

Claims

[Claim 1] A solder bump forming member comprising a base body having multiple recesses with multiple protrusions on its bottom surface, and solder particles in the recesses. [Claim 2] The solder bump forming member according to claim 1, wherein the height of the protrusion is 20% or less of the average particle diameter of the solder particles. [Claim 3] The solder bump forming member according to claim 1, wherein a portion of the solder particles protrudes from the recess. [Claim 4] A solder bump forming member according to any one of claims 1 to 3, wherein the average particle size of the solder particles is 1 to 35 μm and the C.V. value is 20% or less.

Images