KR20220122663A - A member for forming solder bumps, a method for manufacturing a member for forming a solder bump, and a method for manufacturing an electrode substrate with solder bumps - Google Patents

Abstract

A member for forming solder bumps, comprising: a substrate having a plurality of concave portions; and solder particles and a fluidizing agent in the concave portions, wherein the solder particles have an average particle diameter of 1 to 35 µm and a C.V. value of 20% or less.

Description

A member for forming solder bumps, a method for manufacturing a member for forming a solder bump, and a method for manufacturing an electrode substrate with solder bumps

The present invention relates to a member for forming solder bumps, a method for manufacturing a member for forming a solder bump, and a method for manufacturing an electrode substrate with solder bumps.

There is known a solder ball arrangement sheet comprising a mask having a plurality of solder ball insertion holes provided in a predetermined pattern, a solder ball accommodated in the insertion hole, and a fixing agent for holding the solder ball in the insertion hole. (For example, refer patent document 1).

A method for manufacturing a sheet for forming solder bumps is known, which includes the following steps and holds a solder ball or solder powder at a predetermined position (for example, refer to Patent Document 2).

A. Preparing a sheet having, on one side, a plurality of dimples, the bottom surface of which is composed of an adhesive, at predetermined positions; B. Filling each ditch of the sheet with solder powder, and holding the solder powder with an adhesive on the bottom of the ditch; C. Remove the solder powder not held by the adhesive from the sheet, and D. Cover the solder powder in the ditch of the sheet.

There is known a method of forming solder bumps on an electrode by transferring a solder ball disposed in a concave groove to a surface of an adhesive roll, and transferring the solder ball to an adhesive on the electrode (for example, refer to Patent Document 3).

Patent Document 1: Japanese Patent Laid-Open No. 2004-080024 Patent Document 2: International Publication No. 2006/043377 Patent Document 3: Japanese Patent Application Laid-Open No. 2017-157626

In the transfer sheet and manufacturing method shown in Patent Documents 1 and 2, an adhesive layer for holding solder particles is required. Therefore, by heating above the melting point of the solder to melt/unify the solder, and then heat at the time of transferring it on the electrode again, the components of the adhesive layer may be softened, melted, or decomposed, and contaminants may be formed. When contaminants are interposed between the solder and the electrode, there is a fear that the stable formation of the solder bumps is hindered. When the solder bumps are transferred onto the electrode and then these contaminants are removed, the substrate on which the electrode is formed and the semiconductor package are exposed to a cleaning solution, resulting in an increase in the process, defects in the substrate/semiconductor package, and defects due to poor cleaning. etc. may occur.

In Patent Document 3, since the solder balls (particles) are disposed on the electrode via the pressure-sensitive adhesive, there is a fear that the pressure-sensitive adhesive component remains on the surface of the solder ball and causes defects in bonding. Moreover, although control of the thickness of an adhesive and the unevenness|corrugation of the surface of an adhesive is once possible when the size of a solder ball is about 100 micrometers, it becomes difficult as the size becomes small to 50 micrometers and 30 micrometers. Therefore, when solder balls (particles) having a diameter of less than 30 µm are transferred and moved through an adhesive, it becomes difficult to increase the transfer rate.

In addition, there is known a transfer sheet in which solder balls (particles) are uniformly arranged on the surface of a substrate through an adhesive interposed therebetween while contacting each other. It is said that the solder ball surface of this transfer sheet is pressed against the substrate on which the electrode is formed and heated, so that the solder ball can be transferred onto the electrode, and bumps can be formed by subsequent reflow. However, as a result of the inventors examining, when the electrode gap became narrow, the solder bridged between the electrodes, and a short circuit (short-circuit) defect occurred. Since adjacent solder balls are in contact with each other, it is presumed that the solder melts and coalesces due to the heat at the time of transfer to the electrode in any way, resulting in a portion interposed between the adjacent electrodes. In the solder transfer sheet in which the solder particles are uniformly arranged while contacting each other in this way, it is difficult to form solder bumps without short circuit in the case of an electrode spacing of several microns level.

The present invention has been made in view of the above circumstances, and a solder useful for manufacturing a bonded structure excellent in both insulation reliability and conduction reliability even if the connection points of circuit members to be electrically connected to each other are minute. An object of the present invention is to provide a member for forming bumps and a method for manufacturing the same. Another object of the present invention is to provide a method for manufacturing an electrode substrate with solder bumps using the member.

One aspect of the present invention is a member for forming solder bumps, comprising a base having a plurality of concave portions, solder particles and a fluidizing agent in the concave portions, the solder particles having an average particle diameter of 1 to 35 μm and a C.V. value of 20% or less. is about

The said member for solder bump formation is useful in manufacturing the connection structure excellent in both insulation reliability and conduction|electrical_connection reliability even if the connection location of the circuit member which should be electrically mutually connected is minute.

In one aspect of the solder bump forming member, the fluidizing agent may contain at least one selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, benzoic acid, and malic acid. .

In the aspect of the member for solder bump formation, the flat part may be formed in a part of the surface of a solder particle.

In the aspect of the member for solder bump formation, the distance between adjacent recesses may be 0.1 times or more of the average particle diameter of a solder particle.

One aspect of the present invention provides a member for forming solder bumps, comprising a pre-step of preparing a base having a plurality of recesses, solder particles and a fluidizing agent, and a disposing step of disposing solder particles and a fluidizing agent in the recesses. It relates to a manufacturing method of

One aspect of the present invention provides a preparation step of preparing a base having a plurality of concave portions and solder fine particles, a receiving step of accommodating at least a portion of the solder fine particles in the concave portion, and fusing the solder fine particles accommodated in the concave portion to form a concave It relates to a manufacturing method of a member for forming solder bumps, comprising: a fusion step of forming solder particles in a portion; and a pouring step of disposing a fluidizing agent in a concave portion in which the solder particles are formed.

One aspect of the manufacturing method of the member for solder bump formation WHEREIN: The average particle diameter of a solder particle is 1-35 micrometers, and the C.V. value may be 20 % or less.

In one aspect of the method for manufacturing the member for forming solder bumps, the C.V. value of the solder fine particles may exceed 20%.

One aspect of the method for manufacturing the member for forming solder bumps may further include a reducing step of exposing the solder fine particles accommodated in the recesses to a reducing atmosphere before the fusion step.

In one aspect of the method for manufacturing the member for forming solder bumps, in the fusion step, the solder fine particles may be fused in a reducing atmosphere.

One aspect of the present invention provides a preparatory step of preparing a substrate having the member for forming solder bumps and a plurality of electrodes, and a surface of the member for forming solder bumps having a concave portion and a surface of the substrate having electrodes in contact with each other It relates to a method for manufacturing an electrode substrate with solder bumps, comprising: an arrangement step; and a heating step of heating the solder particles to a temperature equal to or higher than the melting point of the solder particles.

In the heating step in one aspect of the method for manufacturing an electrode substrate with solder bumps, the solder particles may be heated to a temperature equal to or higher than the melting point of the solder particles while the members for forming solder bumps and the substrate are brought into contact under pressure.

One aspect of the method for manufacturing an electrode substrate with solder bumps may further include a reduction step of exposing the solder particles to a reducing atmosphere before the arrangement step.

One aspect of the method for manufacturing an electrode substrate with solder bumps may further include a reduction step of exposing the solder particles to a reducing atmosphere after the arrangement step and before the heating step.

In the heating step in one aspect of the method for manufacturing an electrode substrate with solder bumps, the solder particles may be heated to a temperature equal to or higher than the melting point of the solder particles in a reducing atmosphere.

One aspect of the manufacturing method of the electrode substrate with solder bumps may further comprise the removal process of removing the member for solder bump formation from a board|substrate after a heating process.

One aspect of the method for manufacturing an electrode substrate with solder bumps may further include a cleaning step of removing solder particles not bonded to the electrode after the removal step.

According to the present invention, it is possible to provide a member for forming solder bumps useful for manufacturing a bonded structure excellent in both insulation reliability and conduction reliability even when the connection points of circuit members to be electrically connected to each other are minute, and a method for manufacturing the same. . Moreover, according to this invention, the manufacturing method of the electrode substrate with solder bump using the said member can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the member for solder bump formation which concerns on one Embodiment.
Fig. 2(a) is a view of solder particles viewed from the side opposite to the opening of the concave portion in Fig. 1, and Fig. 2(b) is a diagram in which a rectangle circumscribed on the projection image of the solder particles is created by two pairs of parallel lines. It is a figure which shows the distance X and Y (provided that Y<X) between opposing sides in a case.
Fig. 3(a) is a plan view schematically showing an example of a base, and Fig. 3(b) is a cross-sectional view taken along the line Ib-Ib in Fig. 3(a).
4(a) to 4(h) are cross-sectional views schematically showing examples of the cross-sectional shape of the concave portion of the substrate.
Fig. 5 is a cross-sectional view schematically showing a state in which solder fine particles are accommodated in the recesses of the base.
6A and 6B are cross-sectional views schematically showing an example of a manufacturing process of an electrode substrate with solder bumps.
FIG.7(a) and FIG.7(b) are sectional drawing which shows typically an example of the manufacturing process of a bonded structure.
8 : is sectional drawing which shows typically an example of a base|substrate.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described. This invention is not limited to the following embodiment. In addition, unless otherwise indicated, the material illustrated below may be used individually by 1 type, and may be used in combination of 2 or more type. The content of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified, when a plurality of substances corresponding to each component exist in the composition. The numerical range indicated using "to" indicates a range including the numerical values described before and after "to" as the minimum and maximum values, respectively. In the numerical range described step by step in this specification, the upper limit or lower limit of the numerical range of a predetermined step may be substituted with the upper limit or lower limit of the numerical range of another step. In the numerical range described in this specification, the upper limit or lower limit of the numerical range may be substituted with the value shown in the Example.

<Members for forming solder bumps>

In one aspect, the member for forming solder bumps includes a base having a plurality of concave portions, and solder particles and a fluidizing agent in the concave portions, the average particle diameter of the solder particles being 1-35 μm, and the C.V. value is 20% or less. .

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the member for solder bump formation which concerns on one Embodiment. The solder bump formation member 10 includes a base 60 having a plurality of concave portions 62 , and solder particles 1 and a fluidizing agent F in the concave portions 62 . In a predetermined longitudinal cross-section of the member 10 for forming solder bumps, one solder particle 1 is spaced apart from one adjacent solder particle 1 in a lateral direction (left-right direction in FIG. 1). placed so as to The solder particles 1 may be in contact with the side surface and/or the bottom surface of the concave portion 62 . The fluidizing agent F may exist between the solder particle 1 and the bottom surface of the recessed part 62 . The member for solder bump formation may be in the form of a film (film for solder bump formation), a sheet shape (sheet for solder bump formation), etc. may be sufficient as it.

(solder particles)

The average particle diameter of the solder particles 1 is, for example, 35 µm or less, preferably 30 µm or less, 25 µm or less, 20 µm or less, or 15 µm or less. Moreover, the average particle diameter of the solder particle 1 is 1 micrometer or more, for example, Preferably it is 2 micrometers or more, More preferably, it is 3 micrometers or more, More preferably, it is 5 micrometers or more.

The average particle diameter of the solder particles 1 can be measured using various methods according to the size. For example, methods such as a dynamic light scattering method, a laser diffraction method, a centrifugal sedimentation method, an electric detection zone method, and a resonance mass measurement method can be used. Moreover, the method of measuring a particle size from the image obtained by an optical microscope, an electron microscope, etc. can be used. Specific examples of the apparatus include a flow-type particle image analyzer, a microtrac, and a Coulter counter. The average particle diameter of the solder particles 1 is the equivalent projected area diameter (projection area of the particles) when the solder particles 1 are observed from a direction perpendicular to the main surface of the member 10 for forming solder bumps. diameter of a circle having the same area as

The C.V. value of the solder particles 1 is preferably 20% or less, more preferably 10% or less, and still more preferably 7% or less from the viewpoint of realizing more excellent conductive reliability and insulation reliability. In addition, the lower limit of the C.V. value of the solder particle 1 is not specifically limited. For example, the C.V. value of the solder particles 1 may be 1% or more or 2% or more.

The C.V. value of the solder particles 1 is calculated by multiplying the value obtained by dividing the standard deviation of the particle diameter measured by the above-described method by the average particle diameter by 100.

A flat portion may be formed on a part of the surface of the solder particles. FIG. 2A is a view of the solder particles 1 viewed from the side opposite to the opening of the recess 62 in FIG. 1 . The solder particle 1 has a shape in which a flat portion 11 of a diameter A is formed on a part of the surface of a sphere having a diameter B. Further, the solder particles 1 shown in Figs. 1 and 2 (a) have a flat portion 11 because the bottom of the concave portion 62 is flat, but the bottom of the concave portion 62 is non-planar. In the case of a shape, it will have a surface of a different shape corresponding to the shape of a bottom part.

As shown in Fig. 2(a) , the solder particle 1 may have a flat portion 11 formed on a part of the surface thereof. At this time, the surface other than the flat portion 11 is a spherical tube. It is preferable to be a merchant. That is, the solder particles 1 may have a flat portion 11 and a spherical curved portion. The ratio (A/B) of the diameter A of the flat portion 11 to the diameter B of the solder particles 1 may be, for example, more than 0.01 and less than 1.0 (0.01<A/B<1.0), or 0.1 to 0.9. do. The flat portion 11 and the bottom surface of the recessed portion 62 are in contact with each other. As shown in Fig. 1, when the solder particles 1 have a flat portion 11 and the flat portion and the bottom surface of the concave portion are in contact with each other, detachment from the solder bump formation member 10 occurs. it becomes difficult to do Moreover, a flat part may also generate|occur|produce also in the part where the inner wall part of the recessed part 62 and the solder particle 1 contact. However, when manufacturing the member for forming solder bumps, as will be described later, the solder particles 1 are once taken out from the base 60, and the solder particles 1 and the fluidizing agent F are rearranged in the recesses of the base again. In this case, the flat portion 11 and the bottom surface of the concave portion 62 do not necessarily need to be in contact.

In the case where a quadrangle circumscribed on the projection image of the solder particles 1 is created by two pairs of parallel lines, the ratio of Y to X when the distances between opposite sides are X and Y (where Y<X) (Y/X) may be more than 0.8 and less than 1.0 (0.8<Y/X<1.0), and 0.9 or more and less than 1.0 may be sufficient as it. Such a solder particle 1 can be said to be a particle|grains closer to a true sphere. When the solder particle 1 is close to a true sphere, non-uniformity hardly occurs in the contact between the solder particle 1 and the electrode, and stable connection tends to be obtained.

Fig. 2B is a diagram showing the distances X and Y (where Y<X) between opposing sides when a quadrangle circumscribed on a projection image of a solder particle is created by two pairs of parallel lines. For example, arbitrary particles are observed with a scanning electron microscope to obtain a projected image. Two pairs of parallel lines are drawn on the obtained projection image, one pair of parallel lines is arranged at a position where the distance between parallel lines is minimum, and the other pair of parallel lines is arranged at a position where the distance between parallel lines is maximum. /requires X. This operation is performed for 300 solder particles, an average value is calculated, and Y/X of the solder particles is taken.

The solder particles 1 may contain tin or a tin alloy. Examples of the tin alloy 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. Available. Specific examples of these tin alloys include the following examples.

·In-Sn (52 mass% In, 48 mass% Bi, melting point 118°C)

・In-Sn-Ag (In 20 mass%, Sn 77.2 mass%, Ag 2.8 mass% melting point 175°C)

·Sn-Bi (43 mass% Sn, 57 mass% Bi, melting point 138°C)

·Sn-Bi-Ag (42 mass% Sn, 57 mass% Bi, 1 mass% Ag, 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 (99.3 mass% Sn, 0.7 mass% Cu, melting point 227°C)

·Sn-Au (21.0 mass% Sn, 79.0 mass% Au, melting point 278°C)

The solder particles may contain indium or an indium alloy. As an indium alloy, an In-Bi alloy, an In-Ag alloy, etc. can be used, for example. Specific examples of these indium alloys include the following examples.

·In-Bi (In 66.3 mass%, Bi 33.7 mass% Melting point 72°C)

·In-Bi (In 33.0 mass%, Bi 67.0 mass% Melting point 109°C)

·In-Ag (97.0 mass% In, 3.0 mass% Ag, melting point 145°C)

The tin alloy or the indium alloy can be selected according to the use (temperature at the time of connection) of the solder particles 1 and the like. For example, when the solder particles 1 are used for fusion at a low temperature, an In-Sn alloy or a Sn-Bi alloy may be employed. In this case, the fusion can be performed at 150° C. or less. When a material with a high melting point, such as a Sn-Ag-Cu alloy or a Sn-Cu alloy, is employed, high reliability can be maintained even after being left at a high temperature.

The solder particles 1 may contain at least one selected from Ag, Cu, Ni, Bi, Zn, Pd, Pb, Au, P, and B. Among these elements, Ag or Cu may be included from the following viewpoints. That is, when the solder particles 1 contain Ag or Cu, the melting point of the solder particles 1 can be lowered to about 220°C, and the bonding strength with the electrode is further improved, so that better conduction reliability is achieved. easier to obtain

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 Cu content is 0.05 mass % or more, it will become easy to achieve more favorable solder connection reliability. Moreover, when Cu content is 10 mass % or less, it becomes easy to become the solder particle 1 excellent in wettability with a low melting|fusing point, and as a result, the connection reliability of the joint part by the solder particle 1 tends to become favorable.

The Ag 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 Ag content is 0.05 mass % or more, it will become easy to achieve more favorable solder connection reliability. Further, when the Ag content is 10% by mass or less, it is easy to form the solder particles 1 having a low melting point and excellent wettability, and as a result, the connection reliability of the junctions by the solder particles 1 tends to be good.

(Fluidifier)

The fluidizing agent F flows as a fluidized phase at the time of reflow and has an action of pushing the solder particles 1 from the concave portion 62 to the electrode side. Moreover, a flux, an organic solvent, etc. may be sufficient as the fluidizing agent (F). The flux dissolves oxides on the surface of the solder particles and on the electrode surface, and has an action of improving the wettability of the solder to the electrode.

As the fluidizing agent (F), various organic solvents can be used. The boiling point of the fluidizing agent (F) may be higher than the melting point of the solder. When the electrode and the concave portion are replaced and heated, the boiling point of the fluidizing agent (F) is higher than the melting point of the solder, so that the fluidizing agent (F) flows in the concave portion, and according to the flow of the fluidizing agent (F), solder particles also moves When the fluidizing agent (F) and the solder particles flow, the electrode surface and the solder particles easily come into contact, and as a result, the formation of solder bumps is promoted. Therefore, when forming the solder bumps, if at least a heating temperature that is higher than the melting point of the solder particles, higher than the softening point or melting point of the fluidizing agent F, and lower than the boiling point of the fluidizing agent F is passed, the solder bumps are not formed on the electrode. it gets easier After the solder bump formation has been sufficiently performed, if the heating temperature is raised above the boiling point of the fluidizing agent (F), residues derived from the fluidizing agent (F) on the surface of the substrate and on the electrode surface can be reduced.

As various organic solvents that can be used for the fluidizing agent (F), cyclohexane (boiling point: 80°C), cycloheptane (boiling point: 118°C), cyclooctane (boiling point: 149°C), heptane (boiling point: 98°C) ° C), octane (boiling point: 126 ° C), nonane (boiling point: 150 ° C), decane (boiling point: 174 ° C), undecane (boiling point: 196 ° C), dodecane (boiling point: 215 ° C), tridecane (boiling point: 234 °C), tetradecane (boiling point: 254 °C), pentadecane (boiling point: 269 °C), hexadecane (boiling point: 287 °C), heptadecaine (boiling point: 302 °C), octadecane Aliphatic hydrocarbons, such as (boiling point: 317 degreeC) and nonadecaine (boiling point: 330 degreeC), can be used. These aliphatic hydrocarbons are non-polar and do not have a reducing function of solder and metals used in electrodes such as Au, Cu, etc., but can be appropriately selected as a solvent having a boiling point equal to or higher than the melting point of solder. , has a function of bringing the solder particles into contact with the electrode surface.

As various organic solvents which can be used for the fluidizing agent (F), for example, pentanol, hexanol, heptanol, octanol, decanol, ethylene glycol, diethylene glycol, propylene glycol, butyl monohydric and polyhydric alcohols such as renglycol, α-terpineol, and isobornylcyclohexanol (MTPH); Ethylene glycol butyl ether, ethylene glycol phenyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, diethylene glycol isobutyl Ether, diethylene glycol hexyl ether, triethylene glycol methyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether , diethylene glycol butyl methyl ether, diethylene glycol isopropyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, propylene glycol propyl ether, Dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol propyl ether, dipropylene glycol butyl ether, dipropylene glycol dimethyl ether, tripropylene glycol ethers such as colmethyl ether and tripropylene glycol dimethyl ether; Ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, dipropylene glycol methyl ether acetate (DPMA) esters such as ethyl lactate, butyl lactate, γ-butyrolactone, and propylene carbonate; acid amides such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide; aliphatic hydrocarbons such as cyclohexane, octane, nonane, decane, and undecane; aromatic hydrocarbons such as benzene, toluene, and xylene; mercaptans having an alkyl group having 1 to 18 carbon atoms; and mercaptans having a cycloalkyl group having 5 to 7 carbon atoms. Examples of the mercaptans having an alkyl group having 1 to 18 carbon atoms include ethyl mercaptan, n-propyl mercaptan, i-propyl mercaptan, n-butyl mercaptan, i-butyl mercaptan, t-butyl mercaptan, pentyl mercaptan, hexyl mercaptan and dodecyl mercaptan are mentioned. Examples of the mercaptans having a cycloalkyl group having 5 to 7 carbon atoms include cyclopentyl mercaptan, cyclohexyl mercaptan and cycloheptyl mercaptan. In addition, as the organic solvent, alicyclic amines such as monoalkylamine, dialkylamine, trialkylamine, alkanolamine, cyclohexylamine, and dicyclohexylamine, and aromatic amines such as diphenylamine and triphenylamine can be heard Examples of the organic solvent include ethylenediethanolamine, n-butyldiethanolamine, diethanolamine, and N,N-bis(2-hydroxyethyl)isopropanolamine.

As the organic solvent that can be used as the fluidizing agent (F), a glycol ether-based solvent can also be used. For example, as a solvent with a boiling point of 200 degrees C or less, dipropylene glycol monomethyl ether, propylene glycol monobutyl ether, diethylene glycol dimethyl ether, ethylene glycol monoallyl ether, Ethylene glycol monoisopropyl ether is mentioned. Examples of the solvent having a boiling point exceeding 200°C include ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, and ethylene glycol mono-2-ethylhexyl ether. ether, diethylene glycol mono-2-ethylhexyl ether, diethylene glycol dibutyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, and the like. .

As a flux which can be used as a fluidizing agent (F), what is generally used for solder bonding etc. can be used. The flux can be appropriately selected according to the composition of the solder particles, the melting point, the surface state, the conditions of heating and atmosphere at the time of transfer, and the like. Examples thereof include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, phosphoric acid, a derivative of phosphoric acid, an organic halide, hydrazine, an organic acid, and rosin. These may be used individually by 1 type, and may use 2 or more types together.

Ammonium chloride etc. are mentioned as a molten salt. Examples of the organic acid include lactic acid, citric acid, stearic acid, glutamic acid, and glutaric acid. Moreover, as an organic acid which can be used for a flux, a C8-C16 organic acid is mentioned, for example. Examples of the organic acid having 8 to 16 carbon atoms include caprylic acid, methylheptanoic acid, ethylhexanoic acid, propylpentanoic acid, pelagonic acid, methyloctanoic acid, ethylheptanoic acid, propylhexanoic acid, capric acid, and methylnonanoic acid. , ethyloctanoic acid, propylheptanoic acid, butylhexanoic acid, undecanoic acid, methyldecanoic acid, ethylnonanoic acid, propyloctanoic acid, butylheptanoic acid, lauric acid, methylundecanoic acid, ethyldecanoic acid, propylnonanoic acid, butylox Carbonic acid, pentylheptanoic acid, tridecanoic acid, methyldodecanoic acid, ethylundecanoic acid, propyldecanoic acid, butylnonanoic acid, pentyloctanoic acid, myristic acid, methyltridecanoic acid, ethyldodecanoic acid, propylundecanoic acid, butyl Decanoic acid, pentylnonanoic acid, hexyloctanoic acid, pentadecanoic acid, methyltetradecanoic acid, ethyltridecanoic acid, propyldodecanoic acid, butylundecanoic acid, pentyldecanoic acid, hexylnonanoic acid, palmitic acid, methylpentadecanoic acid , ethyltetradecanoic acid, propyltridecanoic acid, butyldodecanoic acid, pentyundecanoic acid, hexyldecanoic acid, heptylnonanoic acid, methylcyclohexanecarboxylic acid, ethylcyclohexanecarboxylic acid, propylcyclohexanecarboxylic acid, butylcyclohexane saturated fatty acids such as carboxylic acid, pentylcyclohexanecarboxylic acid, hexylcyclohexanecarboxylic acid, heptylcyclohexanecarboxylic acid, octylcyclohexanecarboxylic acid, and nonylcyclohexanecarboxylic acid; unsaturated fatty acids such as octhenic acid, nonenoic acid, methylnonenoic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, myristoleic acid, pentadecenoic acid, hexadecenoic acid, palmitoleic acid, and sapienoic acid; and aromatic carboxylic acids such as terephthalic acid, pyromellitic acid, o-phenoxybenzoic acid, methylbenzoic acid, ethylbenzoic acid, propylbenzoic acid, butylbenzoic acid, pentylbenzoic acid, hexylbenzoic acid, heptylbenzoic acid, octylbenzoic acid, and nonylbenzoic acid. An organic acid may be used individually by 1 type, and may be used in combination of 2 or more type. As rosin, activated rosin, inactivated rosin, etc. are mentioned. Resin is a type of rosin whose main component is abietic acid. By using the organic acid or rosin which has two or more carboxyl groups as a flux, the effect that the conduction|electrical_connection reliability between electrodes becomes still higher appears.

The melting point of the flux may be 50°C or higher, 70°C or higher, or 80°C or higher. Melting|fusing point of a flux may be 200 degrees C or less, 160 degrees C or less may be sufficient, 150 degrees C or less may be sufficient, and 140 degrees C or less may be sufficient as it. When the melting point of the flux is equal to or higher than the lower limit and equal to or lower than the upper limit, the flux effect is more effectively exhibited, and the solder particles are more efficiently disposed on the electrode. The range of the melting point of the flux may be 80 to 190°C or 80 to 140°C or less.

Examples of the flux having a melting point in the range of 80 to 190° C. include succinic acid (melting point 186° C.), glutaric acid (melting point 96° C.), adipic acid (melting point 152° C.), pimelic acid (melting point 104° C.), and suberic acid. Dicarboxylic acids, such as (melting point 142 degreeC), benzoic acid (melting point 122 degreeC), malic acid (melting point 130 degreeC), etc. are mentioned. The glidant may contain at least one selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, benzoic acid, and malic acid.

The amount of the fluidizing agent (F) present in the concave portion 62 is not particularly limited, but from the viewpoint of easily obtaining an appropriate flow action, flux effect, etc., 1 to 50 mass may be provided based on 100 parts by mass of the solder particles 1 , 1-20 mass may be provided, and 20-50 mass may be provided. The fluidizing agent (F) may be a solvent or a mixture with a resin material. As a solvent, the various organic solvents mentioned above can be used. If it is a mixture, the density|concentration of the fluidizing agent (F) can be suitably adjusted according to the solder particle (1). In order for the mixture to push the solder particles 1 onto the electrode during reflow, the softening point or melting point may be adjusted so that the fluidity of the mixture is increased by heating. When the softening point or the melting point is higher than room temperature, the solder particles 1 are less likely to fall off from the recessed portions 62 at room temperature, and handling before the solder bump forming step is facilitated. As a solvent which comprises a mixture, a high boiling point solvent etc. are mentioned. The high-boiling-point solvent is difficult to remain on the electrode since it volatilizes by reheating after the solder particles 1 are made to flow on the electrode. As the solvent, an alcohol-based solvent or the like can be used. If it is an alcohol-type solvent, reducing property can be expressed.

(gas)

As the material constituting the base 60 , for example, inorganic materials such as metals such as silicon, various ceramics, glass, and stainless steel, and organic materials such as various resins can be used. Among these, the base 60 may be a material having heat resistance that does not change at the melting temperature of the solder fine particles. In addition, the base 60 may be a material having heat resistance that does not deform even at a temperature at which the solder fine particles are melted. In addition, the base 60 may be made of a material that does not change by alloying or reacting with the material constituting the solder fine particles. In addition, the recessed part 62 of the base|substrate 60 can be formed by well-known methods, such as a cutting method, a photolithography method, and an imprint method. In particular, if the imprint method is used, the concave portion 62 of an accurate size can be formed in a short process.

The surface of the base body 60 may have a coating layer. From the viewpoint of expanding the selectivity of the material that can be used for the base 60, the coating layer may be made of a material that is difficult or not easily alloyed with the material constituting the solder fine particles. As the coating layer, an inorganic substance or an organic substance can be used. As the coating layer, inorganic substances 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, diamond, graphite, etc., fluororesins, polyimides, etc. A heat-resistant resin or the like can be used. In addition, the coating layer may have a role of adjusting wettability with solder. By providing a coating layer on the surface of the base body 60, the wettability with the solder can be appropriately adjusted according to the purpose of use.

As a method of forming the coating layer, laminating, solution dipping, coating, painting, impregnation, sputtering, plating, or the like can be used.

From the viewpoint of facilitating the setting of the conditions of the transfer process, the material of the base 60 may be made of a material having properties close to or the same as that of the electrode on which the solder particles are transferred and the substrate on which the electrode is formed. For example, when the coefficient of thermal expansion (CTE) is close to or the same as the material, positional displacement is unlikely to occur at the time of transfer of the solder particles.

The base 60 may be provided with an alignment mark. What is necessary is just to be able to read this alignment mark with a camera. There may be an alignment mark also on the board|substrate side which has an electrode. By providing the alignment marks of the substrate having the substrate 60 and the electrodes, when the solder particles are transferred onto the electrodes, the alignment marks on the substrate 60 and the substrate having the electrodes are formed by a camera mounted on a positionable device. By reading the alignment mark, it becomes possible to accurately grasp the position of the concave portion 62 having the solder particles and the position of the electrode to which the solder particles are transferred. Moreover, by providing the alignment mark of the board|substrate which has the base|substrate 60 and an electrode, the solder particle can be transcribe|transferred on an electrode with favorable position accuracy.

One or more alignment marks may exist on the base body 60 . If there are two or more alignment marks, the positioning accuracy will increase.

The specific structure of the base body 60 is demonstrated below.

(Organic material monolayer)

The base 60 may be composed of an organic material. As an organic material, a polymeric material may be sufficient, and a thermoplastic, thermosetting, photocurable material, etc. can be used. By using an organic material, the range of selection of physical properties is widened, and therefore, it is easy to form the base 60 according to the purpose. For example, if it is an organic material, it is easy to bend or straighten the base|substrate 60 (including the recessed part 62). If it is an organic material, various methods can be used also for formation of the recessed part 62. As a formation method of the recessed part 62, imprint, photolithography, cutting, laser processing, etc. can be used. In particular, according to the imprint method, an arbitrary shape can be formed on the surface by pressing a mold (mold) having a desired shape against the base 60 made of an organic material. Concave portions 62 having a desired pattern can be formed by forming a convex pattern on a mold (mold) and pressing it against a base 60 made of an organic material. Moreover, a photocurable resin can also be used for formation of the recessed part 62, and when a photocurable resin is apply|coated to a mold (mold), and after exposure, the mold (mold) is peeled, the base with the recessed part 62. (60) can be formed. Moreover, in the case of cutting, the recessed part 62 can be formed with a drill etc.

(Double layer of organic material)

The substrate may be composed of a plurality of organic materials. In addition, the base may have a plurality of layers, and the plurality of layers may be composed of different organic materials, respectively. As an organic material, a polymeric material may be sufficient, and a thermoplastic, thermosetting, photocurable material, etc. can be used. The substrate may have two layers made of an organic material, and a recess may be formed in the organic material layer on one side. By layering, each material can be selected by dividing the function, such as selecting a material suitable for solder wettability, for the material of the concave portion in contact with the solder. For example, FIG. 8 is a cross-sectional view schematically showing an example of a base. The base 600 includes a base layer 601 and a recessed layer 602 . The base layer 601 is a layer that supports the concave portion layer 602, and the concave portion layer 602 is a layer in which the concave portion 62 is formed by processing. A resin material excellent in heat resistance and dimensional stability may be used for the base layer 601 , and a material excellent in the workability of the recess 62 may be selected for the recess layer 602 . For example, a thermoplastic resin such as polyethylene terephthalate or polyimide may be used for the base layer 601 , and a thermosetting resin capable of forming the recessed part 62 by an imprint mold for the recessed part layer 602 may be used. For example, by placing a thermosetting resin between polyethylene terephthalate and an imprint mold and heating and pressurizing it, the base 600 (including the concave portion 62 ) having excellent flatness is obtained. Moreover, when forming the recessed part 62 using a photocurable material, you may use the material with high light transmittance for the base layer 601. As shown in FIG. As a material with high light transmittance, polyethylene terephthalate, transparent (colorless type) polyimide, polyamide, etc. may be sufficient, for example. When the recessed portion 62 is formed using a photocurable material, for example, an appropriate amount of the photocurable material is applied to the surface of the imprint mold, a film of polyethylene terephthalate is placed thereon, and a roller is rotated from the polyethylene terephthalate side. UV light is irradiated while pressurized with Then, by peeling the imprint mold after curing the photocurable material, it is possible to obtain a base 600 having a layer of polyethylene terephthalate and a layer of a photocurable material, and in which the concave portion 62 is formed of the photocurable material. The material configuration of the inner wall and the bottom of the concave portion 62 can be changed. For example, the inner wall and the bottom of the concave portion 62 may be made of the same resin material. Moreover, the inner wall and the bottom part of the recessed part 62 can be made into the structure of different resin materials (for example, a thermosetting material and a thermoplastic material).

Moreover, you may use a photosensitive material as an organic material. The photosensitive material may be a positive photosensitive material or a negative photosensitive material. For example, the recess 62 can be easily formed by forming a photosensitive material in a uniform thickness on the surface of a thermoplastic polyethylene terephthalate film and performing exposure and development. The method using exposure and development (photolithography method) is widely used in the manufacture of semiconductors, wiring boards, etc., and is a method with high versatility. Moreover, as an exposure method, it is also possible to use the direct drawing method like direct laser exposure other than exposure using a mask.

By making the material of the base layer 601 thicker than the thickness of the material forming the concave layer 602 , the physical properties of the entire base 600 can be made dominant as the properties of the material of the base layer 601 . Thereby, for example, even if there is a weakness in the properties of the material forming the recess layer 602, it can be compensated by the material of the base layer 601 . For example, even if the material forming the recessed layer 602 is a material that is easily heat-shrinkable, a material that is difficult to heat-shrink is selected for the material of the base layer 601, and the thickness of the base layer 601 is determined by applying the recessed layer 602 to the material. By making it thicker than the thickness of the material to be formed, the deformation|transformation at the time of heating can be suppressed.

In addition, according to the purpose, such as a combination of a resin material excellent in heat resistance or dimensional stability, and a material with little elution of components at the melting temperature of the solder fine particles, a resin material excellent in heat resistance or dimensional stability, and a material having suitable solder wettability, etc. An organic material can be appropriately selected.

As described above, the substrate may be the substrate 600 composed of the base layer 601 and the recessed layer 602 . For example, by making the recessed part layer 602 a photosensitive material, the recessed part 62 can be produced by photolithography. By using a light or thermosetting material, a thermoplastic material, or the like for the concave portion layer 602 , the concave portion 62 can be easily produced by the imprint method. Moreover, since it is also possible to adjust the characteristics of the whole body by changing the thickness of the base layer 601, there exists an advantage that the base|substrate which has desired characteristics can be manufactured.

(Inorganic material single layer (opaque))

The base 60 may be composed of an inorganic material. From the viewpoint of easily controlling the elution of components and the generation of foreign substances to a low level, for example, silicon (silicon wafer), stainless steel, aluminum, or the like can be used as the inorganic material. When these materials are used in a semiconductor mounting process or the like, countermeasures against contamination are easy, and they can contribute to high yield and stable production. In addition, for example, when transferring solder particles formed in the recessed portion 62 to an electrode on a silicon wafer, if the base 60 is made of a silicon wafer, a material having a similar or the same CTE is used. Thereby, positional shift, bending, etc. are hard to occur, and transcription|transfer with respect to an accurate position becomes possible. As a formation method of the recessed part 62, processing by a laser, cutting, etc., a dry etching or wet etching method, electron beam drawing (For example, FIB processing), etc. can be used. Dry etching is widely used in the manufacture of semiconductors, MEMS, and the like, and can process inorganic materials with high precision from the micron order to the nano order.

(Inorganic material single layer (transparent))

As the substrate 60, glass, quartz, sapphire, or the like can be used. Since these materials are transparent, they can be easily aligned when transferring the solder particles in the recesses 62 to another substrate on which the electrodes are formed. As a formation method of the recessed part 62, processing by a laser, cutting, etc., a dry etching or wet etching method, electron beam drawing (For example, FIB processing), etc. can be used.

The advantage of using an inorganic material is that it is excellent in dimensional stability compared with an organic material. When transferring the solder particles in the concave portion 62 onto the electrode, the transfer can be performed with high positioning accuracy. For example, when transferring solder particles to a plurality of electrodes having a size and pitch on the order of micrometers, if an inorganic material having excellent dimensional stability is used, the solder particles can be transferred to the same position on both electrodes.

(organic-inorganic composite material)

The base may be composed of a plurality of materials. In addition, the base may have a plurality of layers, and the plurality of layers may be composed of different materials, respectively. As the organic-inorganic composite material, for example, a combination of an inorganic material and an inorganic material or a combination of an inorganic material and an organic material can be used. The combination of the inorganic material and the organic material achieves both dimensional stability and workability of the recessed portion 62 . As the base having a combination of an inorganic material and an organic material, for example, a base layer 601 made of an inorganic material such as silicon, various ceramics, glass, stainless steel, or the like, and a recessed layer 602 made of an organic material are formed. The gas provided is mentioned. Such a base can be obtained by, for example, forming a photosensitive material into a film on the surface of a silicon wafer, and forming a recessed part by exposure and development. The inner wall and the bottom of the concave portion 62 may be composed of a photosensitive material, the inner wall of the concave portion 62 may be composed of a photosensitive material, and the bottom of the concave portion 62 may be composed of a silicon wafer. The configuration of the concave portion 62 can be appropriately selected in accordance with the purposes such as wettability with the solder particles in the concave portion 62 and ease of transfer to the electrode. When the inner wall and the bottom of the concave portion 62 are made of a photosensitive material, a photosensitive material layer is provided on the surface of the silicon wafer by forming and curing the photosensitive material on the surface of the silicon wafer, and the photosensitive material is again on the surface of the layer. The method of providing the recessed part 62 by forming into a film and performing exposure and development can be used. In this case, the composition from which the photosensitive material on the side of a silicon wafer surface side and the photosensitive material provided in the outermost layer further differ may be sufficient. The photosensitive material can be appropriately selected in consideration of the wettability of the solder particles, contamination properties, and the like. In particular, when the solder particles formed in the recesses 62 are transferred onto the electrode, the surface of the photosensitive material layer as the outermost layer may come into contact with the electrode or the surface of the substrate having the electrode. Therefore, the photosensitive material which does not damage an electrode and a board|substrate, or does not contaminate an electrode and a board|substrate can be selected suitably. The photosensitive material may be a material that prevents the elution of an uncured component and contamination by a halogen-based material, a silicone-based material, or the like. Further, the photosensitive material may be a material having high resistance to a reducing atmosphere, a flux, or the like at the time of transferring the solder particles to the electrode. For example, the photosensitive material may be a material resistant to a reducing atmosphere such as formic acid, hydrogen, or hydrogen radicals. In addition, the photosensitive material may be a material with high tolerance with respect to the temperature at the time of transferring solder particle|grains to an electrode. Specifically, the photosensitive material may be a material with tolerance to a temperature of 100°C or higher and 300°C or lower. Since the melting point of the solder particles differs depending on the constituent material, the heat-resistant temperature of the photosensitive material can also be selected according to the solder material to be used. When using a tin-silver-copper solder (e.g. SAC305 (melting point 219°C)), which is a lead-free solder widely used in electronic devices, it has a heat resistance of 220°C or higher, especially a heat resistance of 260°C or higher used in the reflow process. material is available. When using a tin-bismuth-based solder (eg SnBi58 (melting point 139°C)), a material having heat resistance of 140°C or higher can be used, and if it is a material having heat resistance of 160°C or higher, the possibility of industrial use is widened. All. In the case of using indium solder (melting point 159°C), a material having heat resistance of 170°C or higher can be used. When using indium-tin solder (eg, melting point 120°C), a material having heat resistance of 130°C or higher can be used.

As another base material, the base body which has the recessed part 62 formed in the thermosetting or thermoplastic resin on the stainless steel plate is mentioned. The base can be obtained by placing a thermosetting material (resin) between the stainless steel plate and the imprint mold, heating under pressure, and then peeling the imprint mold. As another base|substrate, the base|substrate which has the recessed part 62 formed with the photocurable material on the glass plate is mentioned. The substrate can be obtained by applying a photocurable material on a glass plate, exposing while pressing an imprint mold to cure the photocurable material, and peeling the imprint mold. When the concave portion 62 is formed using the imprint mold, the material configuration of the inner wall and the bottom portion of the concave portion 62 may be changed according to the pressing condition. For example, when the pressing conditions are not strict, the inner wall and the bottom of the concave portion 62 may be made of the same resin material. On the other hand, when the pressing conditions are strict, the inner wall of the concave portion 62 may be made of a resin material, and the bottom portion may be made of an inorganic material.

As the material of the base layer 601 , a composite material including glass fibers, fillers, and the like and a resin component may be used. As a composite material, the copper clad laminated board for wiring boards, etc. are mentioned. The concave portion 62 can be formed as described above by applying a photosensitive material, a thermosetting resin, a photocuring resin, or the like to the surface of the copper clad laminate. Although a copper clad laminated board mainly contains a large amount of resin material, since it can set it as low CTE by combining with glass fiber, various fillers, etc., the above-mentioned dimensional stability can be ensured. Further, when the electrode is formed on the copper clad laminate, the concave portions 62 are also formed on the same copper clad laminate, so that the CTEs of both become the same or close, and the solder particles in the concave portion 62 are transferred. There is an advantage in that position alignment is easy at the time of operation, and position shift is difficult to occur.

As the material of the recessed portion layer 602, a sealing material for a package may be used. As a sealing material, all of solid, liquid, and film form can be used. The concave portion 62 can be formed by laminating a sealing material in a thin layer on glass, a silicon wafer, or the like and heating under pressure with an imprint mold.

<Method for Manufacturing Solder Bump Formation Member>

A method of manufacturing the member 10 for forming solder bumps includes a preparatory step of preparing a base having a plurality of concave portions and solder fine particles, a receiving step of accommodating at least a portion of the solder fine particles in the concave portions, and solder accommodated in the concave portions. A fusion step of fusing fine particles to form solder particles in the concave portion, and an injection step of disposing (injecting) a fluidizing agent (fluidized phase) in the concave portion where the solder particles are formed.

The manufacturing method of the member 10 for solder bump formation which concerns on 1st Embodiment is demonstrated, referring FIGS. 3-5.

First, the solder fine particles and the base 60 for accommodating the solder fine particles are prepared. Fig. 3A is a plan view schematically showing an example of the base 60, and Fig. 3B is a cross-sectional view taken along the line Ib-Ib in Fig. 3A. The base|substrate 60 shown to Fig.3 (a) has the some recessed part 62. As shown in FIG. The plurality of concave portions 62 may be regularly arranged in a predetermined pattern. According to the shape, size, pattern, etc. of the electrode to be connected, the position and number of the plurality of concave portions 62 may be set.

Although there is no restriction|limiting in particular in the distance L between adjacent recesses, It can be set as 0.1 times or more of the average particle diameter of the solder particle accommodated, and may be 1 time or more. The distance L can be appropriately adjusted by arrangement of the electrodes forming the solder bumps. The distance between the recesses is not the center-to-center distance of the recesses, but the distance from the edge of the recess opening to the edge.

It is preferable that the concave portion 62 of the base 60 is formed in a tapered shape in which the opening area is enlarged from the bottom 62a side of the concave portion 62 toward the surface 60a side of the base 60 . do. That is, as shown in FIG.3(a) and FIG.3(b), the width (in FIG.3(a) and FIG.3(b) of the bottom part 62a of the recessed part 62) It is preferable that width a) is narrower than the width|variety (width b in FIG.3(a) and FIG.3(b)) of the opening in the surface 60a of the recessed part 62. As shown in FIG. In addition, the size (width a, width b, volume, taper angle, depth, etc.) of the recessed part 62 may be set according to the target size of the solder particle.

In addition, the shape of the recessed part 62 may be a shape other than the shape shown in FIG.3(a) and FIG.3(b). For example, the shape of the opening in the surface 60a of the recessed part 62 may be an ellipse, a triangle, a quadrangle, a polygon, etc. other than a circle as shown to Fig.3 (a).

Moreover, the shape of the recessed part 62 in the cross section perpendicular|vertical with respect to the surface 60a may be a shape as shown in FIG. 4, for example. 4(a) to 4(h) are cross-sectional views schematically showing examples of the cross-sectional shape of the concave portion of the substrate. The width (width b) of the opening in the surface 60a of the recessed portion 62 is the maximum width in the cross-sectional shape in any of the cross-sectional shapes shown in FIGS. 4(a) to 4(h). Thereby, the solder particles formed in the recessed portion 62 are easily taken out, and workability is improved. Further, since the width (width b) of the opening is the maximum width in the cross-sectional shape, when the solder particles 1 are transferred onto the electrode, the solder particles 1 are moved from the recesses 62 . It is easy to slip out, and the improvement of the transfer rate can be expected. In addition, by appropriately adjusting the width (width b) of the opening, positional shift when the solder particles 1 are transferred onto the electrode is less likely to occur, and the solder bumps are easily formed at the correct position.

The solder fine particles prepared in the preparation step may contain fine particles having a particle diameter smaller than the width (width b) of the opening in the surface 60a of the concave portion 62, and contain more fine particles having a particle size smaller than the width b It is preferable to do For example, the solder fine particles preferably have a D10 particle diameter of the particle size distribution smaller than the width b, more preferably a D30 particle diameter of the particle size distribution smaller than the width b, and more preferably a D50 particle diameter of the particle size distribution smaller than the width b. do.

The particle size distribution of the solder fine particles can be measured using various methods according to the size. For example, methods such as a dynamic light scattering method, a laser diffraction method, a centrifugal sedimentation method, an electric detection zone method, and a resonance mass measurement method can be used. Moreover, the method of measuring a particle size from the image obtained by an optical microscope, an electron microscope, etc. can be used. Specific examples of the apparatus include a flow-type particle image analyzer, a microtrac, and a Coulter counter.

Although the C.V. value of the solder fine particles prepared in the preparation step is not particularly limited, it is preferable that the C.V. value is high from the viewpoint of improving the filling properties of the concave portion 62 by the combination of large and small fine particles. For example, the C.V. value of the solder fine particles may exceed 20%, preferably 25% or more, more preferably 30% or more.

The C.V. value of the solder fine particles is calculated by multiplying the standard deviation of the particle diameter measured by the method described above by the average particle diameter (D50 particle diameter) by 100.

The solder fine particles may contain tin or a tin alloy. Examples of the tin alloy 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. Available. Specific examples of these tin alloys include the following examples.

·In-Sn (52 mass% In, 48 mass% Bi, melting point 118°C)

・In-Sn-Ag (In 20 mass%, Sn 77.2 mass%, Ag 2.8 mass% melting point 175°C)

·Sn-Bi (43 mass% Sn, 57 mass% Bi, melting point 138°C)

·Sn-Bi-Ag (42 mass% Sn, 57 mass% Bi, 1 mass% Ag, 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 (99.3 mass% Sn, 0.7 mass% Cu, melting point 227°C)

·Sn-Au (21.0 mass% Sn, 79.0 mass% Au, melting point 278°C)

The solder fine particles may contain indium or an indium alloy. As an indium alloy, an In-Bi alloy, an In-Ag alloy, etc. can be used, for example. Specific examples of these indium alloys include the following examples.

·In-Bi (In 66.3 mass%, Bi 33.7 mass% Melting point 72°C)

·In-Bi (In 33.0 mass%, Bi 67.0 mass% Melting point 109°C)

·In-Ag (97.0 mass% In, 3.0 mass% Ag, melting point 145°C)

The tin alloy or the indium alloy can be selected according to the use (temperature at the time of use) of the solder particles and the like. For example, when it is desired to obtain solder particles used for fusion at a low temperature, an In-Sn alloy or a Sn-Bi alloy may be employed. In this case, solder particles capable of being fused at 150°C or less are obtained. When a material with a high melting point, such as a Sn-Ag-Cu alloy or a Sn-Cu alloy, is employed, solder particles capable of maintaining high reliability even after standing at a high temperature can be obtained.

The solder fine particles may contain at least one selected from Ag, Cu, Ni, Bi, Zn, Pd, Pb, Au, P, and B. Among these elements, Ag or Cu may be included from the following viewpoints. That is, when the solder fine particles contain Ag or Cu, there is an effect that better conduction reliability is obtained by obtaining solder particles having excellent bonding strength with an electrode, which can lower the melting point of the obtained solder particles to about 220°C. .

The Cu content of the solder fine particles 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% by mass or more, it is easy to obtain solder particles capable of achieving good solder connection reliability. Moreover, when Cu content is 10 mass % or less, melting|fusing point is low and it becomes easy to obtain the solder particle excellent in wettability, and as a result, the connection reliability of an electrode with a solder bump becomes more favorable easily.

The Ag content of the solder fine particles 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 more, it is easy to obtain solder particles capable of achieving good solder connection reliability. Moreover, when Ag content is 10 mass % or less, it becomes easy to obtain solder particle|grains excellent in wettability with a low melting|fusing point, and as a result, the connection reliability of an electrode with solder bumps becomes more favorable more easily.

In the accommodation step, the solder fine particles prepared in the preparatory step are accommodated in each of the recessed portions 62 of the base 60 . The receiving step may be a step of accommodating all of the solder fine particles prepared in the preparatory step in the concave portion 62, or a part of the solder fine particles prepared in the preparatory step (for example, among the solder fine particles, the opening of the concave portion 62 is It may be a process of accommodating the thing smaller than the width b) in the recessed part 62 .

5 is a cross-sectional view schematically showing a state in which the solder fine particles 111 are accommodated in the recessed portions 62 of the base 60. As shown in FIG. As shown in FIG. 5 , a plurality of solder fine particles 111 are accommodated in each of the plurality of concave portions 62 .

The amount of the solder fine particles 111 accommodated in the concave portion 62 is, for example, preferably 20% or more, more preferably 30% or more, still more preferably 50% or more, with respect to the volume of the concave portion 62, , more preferably 60% or more. Thereby, the dispersion|variation in storage capacity is suppressed, and it becomes easy to obtain solder particle|grains with a smaller particle size distribution.

The method of accommodating the solder fine particles in the recessed portion 62 is not particularly limited. The accommodation method may be either dry or wet. For example, by disposing the solder fine particles prepared in the preparatory step on the base 60 and rubbing the surface 60a of the base 60 using a squeegee, while removing the excess solder fine particles, the recess 62 Sufficient solder fine particles can be accommodated in the inside. When the width b of the opening of the concave portion 62 is larger than the depth of the concave portion 62 , solder fine particles may protrude from the opening of the concave portion 62 . When a squeegee is used, the solder fine particles protruding from the opening of the concave portion 62 are removed. As a method of removing the excess solder fine particles, a method such as blowing compressed air or rubbing the surface 60a of the base 60 with a bundle of nonwoven fabrics or fibers can also be mentioned. These methods are preferable for handling solder fine particles, which are easily deformed, because their physical force is weaker than that of a squeegee. In addition, in these methods, the solder fine particles protruding from the opening of the concave portion 62 may be left in the concave portion.

The fusing step is a step of fusing the solder fine particles 111 accommodated in the recessed portion 62 (for example, by heating to 130 to 260° C.) to form the solder particles 1 inside the recessed portion 62 . . The solder fine particles 111 accommodated in the concave portion 62 are united by melting and spheroidized by surface tension. At this time, at the contact portion of the concave portion 62 with the bottom portion 62a , the molten solder follows the bottom portion 62a to form the flat portion 11 . As a result, the solder particles 1 to be formed have a shape having a flat portion 11 on a part of the surface. In this way, the member 10 for solder bump formation shown in FIG. 1 is obtained.

As a method of melting the solder fine particles 111 accommodated in the concave portion 62 , a method of heating the solder fine particles 111 above the melting point of the solder is exemplified. The solder fine particles 111 do not melt even when heated at a temperature equal to or higher than the melting point under the influence of the oxide film, or do not become wetted and diffused, so that they do not coalesce in some cases. For this reason, the solder fine particles 111 are exposed to a reducing atmosphere, the surface oxide film of the solder fine particles 111 is removed, and then the solder fine particles 111 are melted by heating to a temperature equal to or higher than the melting point of the solder fine particles 111, Wet diffusion and consolidation can be achieved. In addition, it is preferable to perform melting of the solder fine particles 111 in a reducing atmosphere. By heating the solder fine particles 111 above the melting point of the solder fine particles 111 and providing a reducing atmosphere, the oxide film on the surface of the solder fine particles 111 is reduced, and the melting, wetting diffusion, and coalescence of the solder fine particles 111 are reduced. Easier to proceed efficiently. That is, the manufacturing method of the member for solder bump formation may further comprise the reducing process of exposing the solder microparticles|fine-particles accommodated in the recessed part to a reducing atmosphere before a fusion process. Further, in the fusion step of the method for manufacturing the member for forming solder bumps, the solder fine particles may be fused in a reducing atmosphere.

The method of setting the reducing atmosphere is not particularly limited as long as the above-described effect is obtained, and for example, there is a method using hydrogen gas, hydrogen radical, formic acid gas, and the like. 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, the solder fine particles 111 can be melted in a reducing atmosphere. These apparatuses may be equipped with a heating apparatus, a chamber filled with an inert gas (nitrogen, argon, etc.) in the furnace, a mechanism for vacuuming the chamber, and the like, thereby making it easier to control the reducing gas. In addition, if the inside of the chamber can be evacuated, voids can be removed by reduced pressure after the solder fine particles 111 are melted and united, and the solder particles 1 having much superior connection stability can be obtained.

Profiles such as reduction and dissolution conditions, temperature, and furnace atmosphere adjustment of the solder fine particles 111 may be appropriately set in consideration of the melting point of the solder fine particles 111, the particle size, the size of the concave portion, the material of the base 60, and the like. . For example, after inserting the gas 60 filled with the solder fine particles 111 into the recesses into the furnace and evacuating the furnace, a reducing gas is introduced to fill the furnace with the reducing gas, and the solder fine particles 111 are evacuated. ), the reducing gas is removed by vacuum evacuation, and then heated to above the melting point of the solder fine particles 111 to dissolve and coalesce the solder fine particles, and the solder particles in the recesses 62 . After forming , the temperature inside the furnace is returned to room temperature after filling with nitrogen gas, so that the solder particles 1 can be obtained. Further, for example, the gas 60 filled with the solder fine particles 111 in the recess is inserted into the furnace and evacuated, then a reducing gas is introduced to fill the furnace with the reducing gas, and the inside of the furnace is evacuated. The solder fine particles 111 are heated with a heating heater to remove the surface oxide film of the solder fine particles 111, the reducing gas is removed by vacuum evacuation, and then heated above the melting point of the solder fine particles 111, After the solder particles are dissolved and united to form solder particles in the recessed portions 62, the furnace temperature is returned to room temperature after filling with nitrogen gas to obtain the solder particles 1 . By heating the solder fine particles in a reducing atmosphere, there is an advantage in that the reducing power is increased and the surface oxide film of the solder fine particles can be easily removed.

Further, for example, after inserting the gas 60 filled with the solder fine particles 111 into the recesses into the furnace and evacuating the furnace, a reducing gas is introduced to fill the furnace with the reducing gas, and the furnace is filled with the reducing gas. By heating the solder fine particles 111 above the melting point of the solder fine particles 111 by means of a heating heater, the surface oxide film of the solder fine particles 111 is removed by reduction, and at the same time, the solder fine particles are dissolved and united, thereby dissolving the solder particles in the concave portion 62. After forming, the reducing gas is removed by vacuum evacuation, voids in the solder particles are further reduced, and after filling with nitrogen gas, the furnace temperature is returned to room temperature to obtain the solder particles 1 . In this case, since adjustment of the rise and fall of the furnace temperature needs only once each, there exists an advantage that it can process in a short time.

After the solder particles are formed in the concave portions 62 described above, a step of removing the surface oxide film that has not been completely removed by setting the furnace to a reducing atmosphere once more may be added. Thereby, it is possible to reduce residues such as solder fine particles remaining unfused and a part of the oxide film remaining unfused.

When a conveyor furnace at atmospheric pressure is used, the gas 60 filled with the solder fine particles 111 in the recesses is placed on a conveying conveyor, and the solder particles 1 can be obtained by continuously passing through a plurality of zones. For example, the gas 60 filled with the solder fine particles 111 in the recess is placed on a conveyor set at a constant speed, and filled with an inert gas such as nitrogen or argon at a temperature lower than the melting point of the solder fine particles 111 . After passing through a zone in which a reducing gas such as formic acid gas having a temperature lower than the melting point of the solder fine particles 111 exists, the oxide film on the surface of the solder fine particles 111 is removed, and then the solder fine particles are passed through the zone. The solder fine particles 111 are melted and coalesced by passing through a zone filled with an inert gas such as nitrogen or argon having a temperature equal to or higher than the melting point of (111), and then passed through a cooling zone filled with an inert gas such as nitrogen or argon. Thus, the solder particles 1 can be obtained. For example, a gas 60 filled with the solder fine particles 111 in the recess is placed on a conveyor set at a constant speed, and filled with an inert gas such as nitrogen or argon at a temperature equal to or higher than the melting point of the solder fine particles 111. passing through the zone, and then passing through a zone in which a reducing gas such as formic acid gas having a temperature higher than or equal to the melting point of the solder fine particles 111 exists to remove the oxide film on the surface of the solder fine particles 111, and melt and coalesce, Then, the solder particles 1 can be obtained by passing through a cooling zone filled with an inert gas such as nitrogen or argon. Since said conveyor furnace can process at atmospheric pressure, it can also process film-form material continuously by roll-to-roll. For example, a continuous roll product of the substrate 60 filled with the solder fine particles 111 in the concave portion is produced, and a roll unwinder is installed at the inlet side of the conveyor furnace and a roll winder is installed at the outlet side of the conveyor furnace, and a constant speed is performed. By conveying the furnace base 60 and passing it through each zone in the conveyor furnace, the solder fine particles 111 filled in the recesses can be fused.

According to the preparatory process - the fusion process, the solder particles 1 of a uniform size can be formed irrespective of the material and shape of the solder fine particles 111 . For example, indium solder can be precipitated by plating, but it is difficult to precipitate in a granular form, and it is soft and difficult to handle. However, in the above method, indium-based solder particles having a uniform particle diameter can be easily produced by using indium-based solder fine particles as a raw material. In addition, since the formed solder particles 1 can be handled while being accommodated in the recesses 62 of the base 60, transportation and storage can be carried out without deforming the solder particles 1 . Further, since the formed solder particles 1 are accommodated in the recesses 62 of the base 60, they can be brought into contact with the electrode without deforming the solder particles. The average particle diameter of the solder particle|grains obtained may be 1-35 micrometers, and the C.V. value may be 20 % or less.

Further, the fine solder particles 111 may have large variations in particle size distribution, may be distorted in shape, and can be suitably used as a raw material if they can be accommodated in the recesses 62 .

Further, in the above method, the base 60 can freely design the shape of the concave portion 62 by lithography, machining, imprinting, or the like. Since the size of the solder particles 1 depends on the amount of the solder fine particles 111 accommodated in the recesses 62, the size of the solder particles 1 can be freely designed according to the design of the recesses 62. .

Next, in the step of disposing the fluidizing agent, the fluidizing agent is disposed in the recessed portions 62 in which the solder particles 1 are formed. Although it does not specifically limit as a method of disposing the fluidizing agent, For example, a method of immersing and raising the gas 60 in a liquid fluidizing agent solution, and a liquid fluidizing agent on the base 60 (especially on the concave portion 62 ) e) methods, such as application|coating and dripping, are mentioned. Further, in the case of a solid fluidizing agent, a fluidizing agent having a diameter smaller than the diameter of the concave portion 62 is disposed on the surface of the base 60 and filled in the concave portion 62 with a squeegee. can be heard Alternatively, a method of disposing a fluidizing agent by CVD, vapor deposition, sputtering, or the like is exemplified. You may remove the excess fluidizing agent which overflowed from the recessed part 62. As a method of removal, methods, such as volatilization by pressure_reduction|reduced_pressure, a squeegee, wiping, scraping, laser etching, blasting, are mentioned, for example.

For example, an appropriate amount of a liquid fluidizing agent is dripped onto the base 60 (on the recessed part 62), and filled in the recessed part 62 while spreading the liquid fluidizing agent with a squeegee, and then again using a squeegee to the recessed part. The excess liquid fluidizing agent that was not filled in (62) can be removed. The fluidizing agent that cannot be completely removed with a squeegee can be wiped off with, for example, a dust-free clean cloth or the like.

The manufacturing method of the member 10 for forming solder bumps may include a pre-step of preparing a base having a plurality of recesses, solder particles and a fluidizing agent, and a disposing step of disposing solder particles and a fluidizing agent in the recesses. do. In this way, the solder particles 1 are once taken out from the base 60, and the solder particles 1 and the fluidizing agent F are rearranged in the recesses of the base again, so that the member for forming solder bumps can be produced. In this method, the solder particles 1 are separated from the solder fine particles 111 that did not become the solder particles 1 in the melting process, the solder fine particles 111 existing outside the concave portion 62, and other residues, foreign substances, etc. can do. Specifically, through a melting step, the base 60 having the solder particles 1 in the recessed portions 62 is immersed in a solvent, and the solder particles 1 are taken out from the recessed portions 62 . After pulling up the gas 60 from which the solder particles 1 have been taken out from the solvent, the solvent is passed through a filter, mesh, or the like to remove foreign substances from the solvent. Thereafter, the solder particles 1 are once dispersed in a solvent and allowed to stand to perform sedimentation separation. By performing sedimentation separation, the solder particles 1 and residues (for example, the solder fine particles 111 and foreign substances) are separated to obtain a mixture of the solder particles 1 and the solvent. After sedimentation separation is performed a plurality of times to further remove residues, the mixture of the solder particles (1) and the solvent is vacuum dried to obtain high-purity solder particles (1). In the arrangement step, the solder particles 1 are rearranged in the recesses 62 on the surface of the base 60 again. A glidant may then be placed in the recess 62 . Alternatively, after the fluidizing agent has been previously disposed in the recessed portion 62 , the solder particles 1 may be disposed in the recessed portion 62 . Alternatively, the fluidizing agent and the solder particles 1 may be mixed in advance, and the mixture may be disposed in the recessed portion 62 . The substrate for rearranging the solder particles may be a substrate used when producing the solder particles, or may be a substrate different from that.

Further, as the solder particles 1, in addition to those obtained by the above-described method, an atomizing method, a water atomizing method, a method for cutting and dissolving a thin wire, a method for producing a micro solder liquid droplet using a precision discharge head, etc. What was produced by a well-known method can be used.

<Method for manufacturing electrode substrate with solder bumps>

A method for manufacturing an electrode substrate with solder bumps includes a preparatory step of preparing a substrate having the above-mentioned solder bump-forming member and a plurality of electrodes, and a surface of the solder bump-forming member having a concave portion and a surface of the substrate having an electrode are opposite to each other. It includes a batching step of bringing the solder particles into contact with each other and a heating step of heating the solder particles to a temperature equal to or higher than the melting point of the solder particles.

As a specific example of the board|substrate (circuit member) which has a some electrode on the surface, Chip components, such as an IC chip (semiconductor chip), a resistor chip, a capacitor chip, and a driver IC; A rigid-type package substrate is mentioned. These circuit members are provided with a circuit electrode, and it is common that it is provided with many circuit electrodes. As another example of the board|substrate which has a some electrode on the surface, wiring boards, such as a flexible tape board|substrate which has a metal wiring, a flexible printed wiring board, and the glass substrate on which indium tin oxide (ITO) was vapor-deposited is mentioned.

Specific examples of the electrode include 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, and electrodes such as indium tin oxide. The electrode can be formed by electroless plating or electrolytic plating or sputtering or etching of metal foil.

6A and 6B are cross-sectional views schematically showing an example of a manufacturing process of an electrode substrate with solder bumps. In the base 60 shown in FIG. 6A , one solder particle 1 and a fluidizing agent F are accommodated in each of the recessed portions 62 . On the other hand, the substrate 2 has a plurality of electrodes 3 on the surface. The surface on the side of the opening of the concave portion 62 of the base 60 is brought into contact with the surface on the side of the electrode 3 of the substrate 2 facing each other. The number of solder particles 1 in contact with each electrode 3 is not particularly limited, and one particle may be used for one electrode, or a plurality of particles may be used for one electrode. In addition, since the force (for example, intermolecular force such as van der Waals force) acting between the solder particles 1 and the concave portion 62 is large compared to the gravity added to the solder particles 1, the gas 60 ), the solder particles 1 do not fall off and remain in the concave portion 62 even when the main surface is directed downward. Further, when at least a part of the solder particles 1 is in contact with the bottom and/or inner wall of the concave portion 62 and has a flat portion, the solder particles 1 are in close contact with the concave portion 62 , Yes, it is difficult to drop out.

The heated fluidizing agent ( The solder particles 1, which are easily flowed by F), come into contact with the electrode 3 and melt, and solder bumps are formed on the electrode 3 . From the viewpoint of more suitably bonding the solder particles 1 and the electrode 3, in the heating step, the solder bump forming member 10 and the substrate 2 are brought into contact with each other under pressure. may be heated to a temperature equal to or higher than the melting point of the solder particles. The pressurized state is a state in which the solder bump formation member 10 and the substrate 2 are pressed in the direction of arrows A and B in FIG. 6A with a force of about 30 to 600 Pa. The solder particle 1 is accommodated in the recessed part 62, and is pressed with respect to the electrode. Therefore, even if it flows by the action of the fluidizing agent F, it is difficult for the solder particles 1 in the adjacent recesses 62 to mix with each other, so that solder bumps of the same size can be formed only on the desired electrode. Moreover, it is difficult for solder to bridge adjacent electrodes, and short circuit failure can be suppressed.

Since the solder particles 1 are rapidly oxidized by heating in the atmosphere and wet diffusion on the electrode 3 is unlikely to occur, the atmosphere at the time of heating is preferably a deoxidized atmosphere. For example, an atmosphere of an inert gas such as nitrogen or argon, a vacuum atmosphere, or the like may be used. As the furnace, reflow furnaces (under nitrogen atmosphere) and vacuum reflow furnaces generally used in the solder bonding process can be used, and conveyor-type reflow furnaces under nitrogen atmosphere and batch-type (chamber type) reflow furnaces can be used. Noh, etc. can be used. When using these reflow furnaces, if a vacuum step is added after the solder melts, air bubbles (voids) in the solder can be removed. Moreover, a laminator can also be used from a viewpoint of productivity improvement. If it is a roller type laminator, pressurization and heating can be added at the same time. In addition, a vacuum pressurization laminator can also be used. The vacuum pressurization laminator is preferable because it is easy to transfer the solder bumps onto the electrode 3 because the inside of the chamber can be under vacuum and pressurization and heating can be performed simultaneously. Moreover, since continuous conveyance by a carrier film is possible, there also exists an advantage which can make productivity high.

The solder particles 1 may not melt or do not wet and diffuse even when heated to a temperature equal to or higher than the melting point under the influence of the oxide film. For this reason, the solder particles 1 can be melted by exposing the solder particles 1 to a reducing atmosphere, removing the surface oxide film of the solder particles 1, and then heating the solder particles 1 to a temperature equal to or higher than the melting point of the solder particles 1 . have. Moreover, it is preferable to perform melting of the solder particle 1 in a reducing atmosphere. By heating the solder particles 1 above the melting point of the solder particles 1 and providing a reducing atmosphere, the oxide film on the surface of the solder particles 1 is reduced, and the oxide film on the electrode surface is further reduced, so that the solder particles ( 1) Melting and wetting diffusion become easy to advance efficiently. That is, the method for manufacturing an electrode substrate with solder bumps may further include a reducing step of exposing the solder particles (and/or electrodes) to a reducing atmosphere before the arrangement step or after the arrangement step and before the heating step. Further, in the heating step of the method for manufacturing an electrode substrate with solder bumps, the solder particles may be heated to a temperature equal to or higher than the melting point of the solder particles in a reducing atmosphere. In the heating step of forming solder bumps on the electrodes, by bringing the electrode and the opening surfaces of the solder bump forming member into close contact (in a pressurized state as necessary), solder bumps are formed only on the electrodes, and a bridge between adjacent electrodes by solder is likely to be suppressed.

About the detail of a reducing atmosphere, description of the manufacturing method of the member for solder bump formation can be referred suitably.

After the heating step, by cooling the whole, the top of the electrode 3 and the solder bumps 1A formed by melting the solder particles 1 are adhered to each other, and both are electrically connected. The manufacturing method of the electrode substrate with solder bumps may further comprise the removal process of removing the member for solder bump formation from a board|substrate after a heating process. After the solder bumps 1A are formed on the electrode 3 , the electrode substrate 20 with solder bumps can be obtained by removing the solder bump formation member 10 from the substrate 2 (removal step). Fig. 6B is a schematic diagram of the electrode substrate 20 with solder bumps obtained in this way.

On the obtained electrode substrate 20 with solder bumps, the solder particles 1 detached from the recessed portions 62 but not provided for bonding with the electrode 3 may exist. Therefore, the manufacturing method of the electrode board|substrate with a solder bump may further provide the washing|cleaning process of removing the solder particle|grains 1 which are not couple|bonded with the electrode after a removal process. Examples of the cleaning method include blowing compressed air or rubbing the substrate surface with a bundle of nonwoven fabrics or fibers. Moreover, when the fluidizing agent F exists as a residue on the electrode substrate 20 with a solder bump, this fluidizing agent can be removed by a washing|cleaning process. In a washing|cleaning process, the solution in which the fluidizing agent (F) melt|dissolves easily can be used.

According to the manufacturing method of the electrode board|substrate with solder bumps, the electrode board|substrate 20 with solder bumps provided with the board|substrate 2, the electrode 3, and the solder bump 1A in this order can be obtained.

<Method for manufacturing bonded structure>

7(a) and 7(b) are cross-sectional views schematically showing an example of a manufacturing process of a bonded structure. The manufacturing method of a bonded structure is demonstrated, referring FIG.7(a) and FIG.7(b). First, the electrode substrate 20 with solder bumps shown in Fig. 6B is prepared in advance. In addition, another substrate 4 having a plurality of different electrodes 5 on the surface is prepared. Then, both are arranged so that the solder bump 1A and the other electrode 5 face each other. Then, it presses in the thickness direction (direction of arrow A and arrow B shown to Fig.7 (a)) of the laminated body of these members. By heating the whole to at least a temperature higher than the melting point of the solder bump 1A (for example, 130 to 260° C.) during pressurization, the solder bump 1A is melted between the electrode 3 and the other electrode 5 . do. Then, by cooling the whole, the solder layer 1B is formed between the electrode 3 and the other electrode 5, and the electrodes are electrically connected. In order to suppress oxidation of the solder bump 1A and the electrode 5, it is preferable to heat in an atmosphere in which oxygen is blocked. For example, heating in an inert gas atmosphere such as nitrogen is preferable. Specifically, a vacuum reflow furnace, a nitrogen reflow furnace, or the like can be used.

Moreover, in order to melt|dissolve the solder bump 1A by heating, and to join the electrode 3 and the electrode 5 which oppose more suitably, it is preferable to heat in a reducing atmosphere. In order to set it as a reducing atmosphere, hydrogen gas, a hydrogen radical, formic acid, etc. can be used. Specifically, a hydrogen reduction furnace, a hydrogen reflow furnace, a hydrogen radical furnace, a formic acid furnace, these vacuum furnaces, a continuous furnace, and a conveyor furnace can be used. By using the 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 bumps 1A are easily wetted and diffused into the electrode 5, and the solder A more stable bond is achieved between the electrode 3 and the electrode 5 via the layer 1B.

Moreover, in order to implement|achieve a stable connection, you may apply pressure. The electrode substrate 20 with solder bumps shown in Fig. 6B is prepared in advance. In addition, another substrate 4 having a plurality of different electrodes 5 on the surface is prepared. Then, both are arranged so that the solder bump 1A and the other electrode 5 face each other. Then, it presses in the thickness direction (direction of arrow A and arrow B shown to Fig.7 (a)) of the laminated body of these members. By heating the whole to at least a temperature higher than the melting point of the solder bump 1A (for example, 130 to 260° C.) during pressurization, the solder bump 1A is melted between the electrode 3 and the other electrode 5 . do. Then, by cooling the whole, the solder layer 1B is formed between the electrode 3 and the other electrode 5, and the electrodes are electrically connected. Also in this case, in order to suppress oxidation of the surfaces of the solder bumps 1A, the electrodes 5, and the electrodes 3, it is preferable to perform the above steps under vacuum, in an inert gas atmosphere such as nitrogen, or in a reducing atmosphere. As a method of setting it as a reducing atmosphere, the above-mentioned hydrogen gas, a hydrogen radical, formic acid, etc. are mentioned. Specifically, a hydrogen reduction furnace, a hydrogen reflow furnace, a hydrogen radical furnace, a formic acid furnace, these vacuum furnaces, a continuous furnace, a conveyor furnace, etc. can be used.

As a method of setting the reducing atmosphere, a material having a reducing action can be used. For example, a flux material or a material containing a flux component can be disposed in the vicinity of the solder bump 1A, the electrode 5 and the electrode 3 . Pastes, films, etc. containing the flux material and the material containing the flux component can be used. First, the electrode substrate 20 with solder bumps shown in Fig. 6B is prepared in advance. A paste containing a flux material or a flux component is disposed on the entire surface of the electrode substrate 20 on which the solder bumps 1A are formed, or near the solder bumps 1A and the electrode 3 including the solder bumps 1A. . In addition, another substrate 4 having a plurality of different electrodes 5 on the surface is prepared. Then, both are arranged so that the solder bump 1A and the other electrode 5 face each other. Thereafter, in a state in which the solder bump 1A and the other electrode 5 are brought into contact with each other via, for example, a flux material or a paste containing a flux component, a temperature higher than the melting point of the solder bump 1A (for example, , 130°C to 260°C), the solder bump 1A is melted between the electrode 3 and the other electrode 5 . Then, by cooling the whole, the solder layer 1B is formed between the electrode 3 and the other electrode 5, and the electrodes are electrically connected. After that, when the flux component is removed by washing, corrosion of the solder layer 1B, the electrode 3 and the electrode 5 due to the flux residue can be suppressed.

As another method, the electrode substrate 20 with solder bumps shown in Fig. 6B is prepared in advance. In addition, another substrate 4 having a plurality of different electrodes 5 on its surface is prepared, and the flux material or flux component is provided on the entire surface of the substrate 4 having the electrodes 5 or in the vicinity of the surface of the electrode 5 . Place the paste containing Then, both are arranged so that the solder bump 1A and the other electrode 5 face each other. Thereafter, in a state in which the solder bump 1A and the other electrode 5 are brought into contact with each other via, for example, a paste containing a flux material and a flux component, a temperature higher than the melting point of the solder bump 1A (for example, , 130°C to 260°C), the solder bump 1A is melted between the electrode 3 and the other electrode 5 . Then, by cooling the whole, the solder layer 1B is formed between the electrode 3 and the other electrode 5, and the electrodes are electrically connected.

In addition, a film containing a flux component can also be used. The electrode substrate 20 with solder bumps shown in Fig. 6B is prepared in advance. A film containing a flux component is disposed on the side of the electrode substrate 20 on which the solder bumps 1A are formed. In addition, another substrate 4 having a plurality of different electrodes 5 on the surface is prepared. Then, both are arranged so that the solder bump 1A and the other electrode 5 face each other. Thereafter, the solder bump 1A and the other electrode 5 are brought into contact with each other via a film containing a flux component, or pressure is applied between the opposing electrode 3 and the electrode 5, A temperature higher than the melting point of the solder bump 1A (for example, 130°C to 260°C) in a state where the solder bump 1A and the electrode 5 are brought into contact with the film containing the flux component from between them. By heating at least with a furnace, the solder bump 1A between the electrode 3 and the other electrode 5 is melted. Then, by cooling the whole, the solder layer 1B is formed between the electrode 3 and the other electrode 5, and the electrodes are electrically connected.

The paste and film containing the flux component may contain a thermosetting material. Thereby, the thermosetting component hardens|cures simultaneously with the melt|dissolution of the solder bump 1A, and the electrode substrate 20 and the board|substrate 4 can be fixed. The thermosetting material may be cured by heating again in a subsequent step separately from the melting heating of the solder bumps 1A. Moreover, you may arrange|position the film containing a flux component in advance on the side of the surface on which the electrode 5 was formed of the board|substrate 4 . The selection of the arrangement position of whether to arrange the film containing the flux component on the side of the solder bump 1A or on the side of the substrate 4 having the electrode 5 depends on the shape of the electrode, the shape of the solder bump 1A, and It can select suitably according to size, the circumstances on a bonding process, etc.

As a heating method for dissolving the solder bumps 1A, for example, a heating plate in a reflow furnace is heated under vacuum and transferred to the solder bumps 1A via the substrate 2 and the substrate 4 in contact with the heating plate. There is a method using radiation such as infrared rays. Moreover, in addition to or in combination with the heating method using the heating plate and infrared rays mentioned above, the method of heating the solder bump 1A via heated gas and gas can be used. Specifically, the solder bump 1A can be heated by heating an inert gas, nitrogen, hydrogen, hydrogen radicals, and formic acid. The flux material and flux component may contain at least one selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, benzoic acid, and malic acid.

As another method, the method using electromagnetic waves, such as a microwave, is mentioned. For example, a specific electromagnetic wave in which the components of the electrode 3, the electrode 5, and the solder bump 1A are heated can be applied from the outside. For example, when the substrate 4 and the substrate 2 are resin substrates, when a specific electromagnetic wave is irradiated from the outside of the substrate 4 and the substrate 2, the electromagnetic wave is transmitted through the substrate 4 and the substrate 2 Then, the electrode 3 and the solder bump 1A or the electrode 5 are heated by the electromagnetic wave. In the case of this method, since the part to be joined can be selectively heated, there is an advantage in that unnecessary heat history is not left. For example, even if the substrate 2 and the substrate 4 are materials with low heat resistance, the electrode 3 and the electrode 5 can be securely joined by dissolving the solder bump 1A. Moreover, since it is hard to leave a thermal history in the whole system to be joined, there exists an advantage of being easy to suppress the warpage and decomposition|disassembly after joining. In addition, when using microwaves, as described above, the solder bumps 1A can be dissolved in a shorter time than using a heating plate, infrared rays, heating gas, etc., so that the thermal history of the entire system to be joined can be reduced. There is an advantage that there exists, and the above-mentioned effect is easy to be acquired. In addition, if microwaves are used, only the portions of the electrode 3 to be joined or dissolved, the solder bump 1A, and the electrode 5 can be locally heated. Therefore, it is not necessary to heat the entire system, and even if there is a material with low heat resistance or other electronic components that do not want to be heated, even in the vicinity of the electrode 3 and the electrode 5, the solder bump 1A can be melted and joined. can

As another method, the method using an ultrasonic wave is mentioned. For example, when an ultrasonic vibrator is disposed on the side opposite to the electrode 3 of the substrate 2 and ultrasonic waves are applied, the solder bumps 1A are melted by the vibration energy of the ultrasonic waves. Thereby, the electrode 3 and the electrode 5 which was previously arrange|positioned at the opposing position of the electrode 3 are joined via the solder layer 1B. Since bonding by ultrasonic waves can melt the solder bumps 1A in a short time, there is no need to apply heat to the entire substrate 2 and substrate 4, and the substrate 2 and the substrate 4 have low heat resistance. Even if it is a low material, the electrode 3 and the electrode 5 can be joined reliably.

FIG.7(b) is a schematic diagram of the bonded structure 30 obtained by doing in this way. That is, FIG. 7B shows a state in which the electrode 3 included in the substrate 2 and the other electrode 5 included in the other substrate 4 are connected via a solder layer 1B formed by fusion. is schematically shown. As used herein, the term "fusion bonding" refers to a state in which at least a part of an electrode is joined by a heat-melted solder (solder bump 1A), and then the solder is joined to the surface of the electrode by going through a step of solidifying it. means The connection structure 30 includes a substrate and a first circuit member having a plurality of electrodes on its surface, a second circuit member having another substrate and a plurality of different electrodes on its surface, a plurality of electrodes and a plurality of other electrodes. It can be said that the solder layer is provided between the electrodes. Moreover, the space between a 1st circuit member and a 2nd circuit member can be filled with the underfill material which has an epoxy resin as a main component, for example.

Examples of application objects of the connection structure include: semiconductor memory, connection parts of semiconductor logic chips, etc., primary and secondary mounting connection parts of semiconductor packages, CMOS image elements, laser elements, LED light emitting elements, etc., and cameras and sensors using them. , a liquid crystal display, a personal computer, a mobile phone, a smart phone, a tablet device, etc. are mentioned.

As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to the said embodiment.

Example

Hereinafter, the present invention will be described in more detail by way of Examples, but the present invention is not limited to these Examples.

<Production of film for forming solder bumps>

(Production Example 1)

Step a1: Classification of solder fine particles

For Sn-Bi, 100 g of solder fine particles (manufactured by 5N Plus, melting point 139°C, Type 8) was immersed in distilled water, ultrasonically dispersed, and then left standing to recover solder fine particles floating in the supernatant. This operation was repeated to recover 10 g of solder fine particles. The obtained solder fine particles had an average particle diameter of 1.0 µm and a C.V. value of 42%.

Process b1: Placement in gas

As shown in Table 1, a base having a plurality of recesses of an opening diameter of 2.3 μmφ, a bottom diameter of 2.0 μmφ, and a depth of 2.0 μm (the bottom diameter of 2.0 μmφ is located at the center of the opening diameter of 2.3 μmφ when viewed from the top) ( A polyimide film, 100 µm in thickness) was prepared. The plurality of recesses were regularly arranged at intervals of 1.0 µm. The solder fine particles obtained in step a (average particle diameter of 1.0 µm, C.V. value of 42%) were placed in the recesses of the substrate. Further, excess solder fine particles were removed by rubbing the surface side of the base on which the recesses were formed with a non-adhesive roller to obtain a base in which the solder fine particles were arranged only in the recesses.

Step c1: Formation of solder particles

In step b1, the gas having solder fine particles disposed in the recesses was put into a hydrogen reduction furnace (manufactured by Shinko Seiki Co., Ltd., vacuum soldering apparatus), and after evacuation, hydrogen gas was introduced into the furnace to fill the furnace with hydrogen. Thereafter, the furnace was kept at 280°C for 20 minutes, evacuated again to vacuum, nitrogen was introduced to return to atmospheric pressure, and then the temperature in the furnace was lowered to room temperature to form solder particles inside the recesses.

<Evaluation of Solder Particles>

A part of the base obtained through the step c1 was fixed to the surface of the pedestal for SEM observation, and platinum sputtering was performed on the surface. By SEM, 300 solder particle diameters were measured, and the average particle diameter and C.V. value were computed. A result is shown in Table 2. In addition, the surface shape of a part of the substrate obtained through step c1 is measured using a laser microscope (manufactured by Olympus Co., Ltd., LEXT OLS5000-SAF), the height of the solder particles from the surface of the substrate is measured, and 300 average values are calculated did. A result is shown in Table 2.

Process d1: batch of flux

20 parts by mass of adipic acid was added as a flux component to 90 parts by mass of dihydroterpineol, and the mixture was mixed to form a fluidized bed. This fluidized bed was placed in a recess in which the solder particles obtained in step c1 were arranged. Thereafter, the surface side of the base on which the recesses were formed was rubbed with a rubber squeegee to remove the excess fluidized bed (flux component) that was not filled in the recesses. Thereafter, the substrate surface was further wiped with a dust-free clean cloth to prepare a film for forming solder bumps.

(Production Examples 2 to 6)

Except having changed the recessed part size etc. as Table 1, it carried out similarly to Production Example 1, and produced and evaluated the film for solder bump formation. A result is shown in Table 2.

(Production Example 7)

A film for solder bump formation was produced and evaluated in the same manner as in Production Example 1 except that the following step c2 was performed instead of the step c1. A result is shown in Table 2.

Step c2: Formation of solder particles

In step b1, the gas in which the solder fine particles are disposed in the recesses is introduced into a hydrogen radical reduction furnace (manufactured by Shinko Seiki Co., Ltd., plasma reflow apparatus), and after evacuation, hydrogen gas is introduced into the furnace to purify the furnace. filled with gas. Then, the inside of a furnace was adjusted to 120 degreeC, and hydrogen radical was irradiated for 5 minutes. Thereafter, the hydrogen gas in the furnace was removed by evacuation, heated to 170° C., nitrogen was introduced into the furnace to return to atmospheric pressure, and then the temperature in the furnace was lowered to room temperature to form solder particles.

(Production Examples 8 to 12)

Except having changed the recessed part size etc. as Table 1, it carried out similarly to Production Example 7, the film for solder bump formation was produced, and it evaluated. A result is shown in Table 2.

(Production Example 13)

Instead of the step c1, a film for forming solder bumps was produced and evaluated in the same manner as in Production Example 1 except that the following step c3 was performed. A result is shown in Table 2.

Step c3: formation of solder particles

In step b1, the gas in which the solder fine particles are disposed in the recesses was introduced into a formic acid reduction furnace, evacuated, and then formic acid gas was introduced into the furnace to fill the furnace with the formic acid gas. Then, the inside of a furnace was adjusted to 130 degreeC, and the temperature was maintained for 5 minutes. Thereafter, the formic acid gas in the furnace was removed by evacuation, heated to 180° C., nitrogen was introduced into the furnace to return to atmospheric pressure, and then the temperature in the furnace was lowered to room temperature to form solder particles.

(Production Examples 14 to 18)

Except having changed the recessed part size etc. as Table 1 was carried out, it carried out similarly to Production Example 13, and produced and evaluated the film for solder bump formation. A result is shown in Table 2.

(Production Example 19)

A film for forming solder bumps was produced and evaluated in the same manner as in Production Example 1 except that the following step c4 was performed instead of the step c1. A result is shown in Table 2.

Step c4: formation of solder particles

In step b1, the gas in which the solder fine particles are arranged in the recesses is put into a formic acid conveyor reflono (manufactured by Heller Industries, Inc., 1913MK), and while conveying by the conveyor, the nitrogen zone, nitrogen and formic acid gas adjusted to 190°C The mixing zone and nitrogen zone were passed successively. A nitrogen and formic acid gas mixing zone was passed for 20 minutes to form solder particles in the recesses.

(Production Examples 20-24)

Except having changed the recessed part size etc. as Table 1, it carried out similarly to Production Example 19, and produced and evaluated the film for solder bump formation. A result is shown in Table 2.

[Table 1]

[Table 2]

<Production of evaluation chip with solder bumps>

Step e1: Preparation of the evaluation chip

Seven types of chips with gold bumps (3.0 x 3.0 mm, thickness: 0.5 mm) shown below were prepared.

Chip C1… Area 100μm x 100μm, space 40μm, height 10μm, number of bumps 362

Chip C2… Area 75 μm×75 μm, space 20 μm, height 10 μm, number of bumps 362

Chip C3… Area 40μm x 40μm, Space 16μm, Height: 7μm, Number of bumps 362

Chip C4… Area 20 μm×20 μm, space 7 μm, height: 5 μm, number of bumps 362

Chip C5… Area 10μm x 10μm, Space 6μm, Height: 3μm, Number of bumps 362

Chip C6… Area 10μm x 10μm, Space 4μm, Height: 3μm, Number of bumps 362

Chip C7… Area 5 μm×10 μm, space 3 μm, height: 2 μm, number of bumps 362

Process f1: Solder bump formation (without formic acid gas)

According to the procedures of i) to iii) shown below, using the film for forming solder bumps (Production Example 7) prepared in step c2, solder bumps to the chip with gold bumps (3.0 x 3.0 mm, thickness: 0.5 mm) has formed

i) On a hot plate, a 0.3 mm-thick glass plate was placed, and an evaluation chip was placed on the glass plate with the gold bump facing up.

ii) It was arrange|positioned so that the open surface side of the recessed part of the film for solder bump formation faced downward, and the gold bump surface of an evaluation chip and the film for solder bump formation contacted. Furthermore, a 0.3 mm-thick glass plate was placed on the film for solder bump formation, a stainless steel weight was placed on the glass plate, and the film for solder bump formation was brought into close contact with the gold bump.

iii) A glass cover of a control type into which nitrogen gas enters was prepared. The sample in which the film for solder bump formation was laminated|stacked on this glass cover on the evaluation chip prepared in ii) was covered. Next, nitrogen gas was introduced into the glass cover, and the entire sample was placed under a nitrogen atmosphere. The hot platen of the hotplate was heated up to 160 degreeC, and it heated for 5 minutes. Then, after returning the hotplate to room temperature, nitrogen gas was cut off and it was released to atmosphere. The uppermost weight, the glass plate, and the film for solder bump formation were removed in this order. Then, the evaluation chip was immersed in a methanol solution, the fluidized bed was wash-removed, it vacuum-dried (40 degreeC for 60 minutes), and the evaluation chip with solder bump was obtained.

<Evaluation of solder bumps: no use of formic acid gas>

The evaluation chip obtained through the process f1 was fixed to the pedestal surface for SEM observation, and platinum sputtering was performed on the surface. By SEM, for 30 gold bumps, the number of solder bumps placed on the gold bumps was counted to calculate the average number of solder bumps placed on one gold bump. A result is shown in Table 3. Moreover, the height of the solder bump from the gold bump was measured using the laser microscope (The Olympus Co., Ltd. make, LEXT OLS5000-SAF), and the average value of 100 pieces was computed. A result is shown in Table 3.

Solder bump formation and its evaluation were performed by the method similar to the above except having used the film for solder bump formation of Production Examples 8-12 instead of the film for solder bump formation of Production Example 7.

Table 3 shows the evaluation results.

(Comparative Production Example 1)

A film for forming solder bumps for comparison having solder particles in the recesses was produced in the same manner as in Production Example 8 except that the step d1 (disposition of the flux) was not performed. Solder bump formation and its evaluation were performed by the method similar to process f1 except having used this film for comparative solder bump formation. A result is shown in Table 3.

[Table 3]

In Production Examples 7 to 12, solder bumps could be formed on the gold bumps of the evaluation chip, but in Comparative Production Example 1, solder bumps were not observed on the gold bumps in any of the evaluation chips.

Since there was no flux-containing fluidized bed in the recesses of Comparative Production Example 1, the surface oxide film of the solder particles was not reduced, and wet diffusion of the solder particles to the gold bumps did not occur.

Since the fluidized bed containing the flux component is accommodated in the recesses together with the solder particles, the flux component removes the oxide film on the surface of the solder particles by heating and also cleans the surface of the gold bumps (electrodes). Then, while the solder particles are melted, they are transferred to the surface of the gold bumps by the fluidized bed, so that solder bumps can be formed on the gold bumps. As shown in Fig. 1, since the fluidized bed exists in the recess, the oxide film near the surface of the solder particles facing the gold bumps (electrodes) is removed by the fluidized bed, and the contact between the solder particles and the gold bumps is prevented. is activated In order to heat in a state in which the opening surface of the concave portion is in contact with the gold bump surface, the solder particles may contact the gold bump surface. At this time, since there is a wall surface of the concave portion, the flow of solder particles and flux in the plane direction of the solder bump forming member is suppressed, and solder bumps can be formed on the gold bumps. Further, for the same reason, it is difficult to join solder particles in adjacent concave portions, so that good solder bumps can be formed. It is necessary to control the amount of wetting and diffusion with the gold bump surface depending on the heating temperature and time for forming the bump. It is difficult to couple|bond the solder particle|grains between adjacent ones, and the likelihood in heating temperature and time is large. Therefore, stable solder bump formation for industrial use is achieved. In addition, although a small amount of flux components and solder particles were seen in the portion without gold bumps, they were able to be removed by washing the evaluation chip in methanol. The concave opening faces also face the evaluation chip surface other than the gold bumps, but since the gold bumps are higher than the other surfaces, the concave openings are difficult to reach and the solder particles are difficult to move toward the evaluation chip. Further, even if the opening surface of the recess is partially in contact with the evaluation chip side, since there is no metal (electrode) through which the solder is wetted and diffused, it can be easily removed by subsequent washing. Further, as described above, since the solder particles and flux are present in the recesses, the flow of the solder particles in the surface direction of the member for forming solder bumps is suppressed, and short-circuit defects in the gold bumps are less likely to occur.

As in Comparative Production Example 1, in the absence of a fluidized bed, the surface oxide film of the solder particles cannot be sufficiently reduced even when heated, and it is difficult to flow the solder particles to the gold bumps (electrodes), so it is difficult to form the solder bumps stably. It is difficult.

Process f2: Solder bump formation (using formic acid gas)

According to the procedures of i) to iii) shown below, using the film for forming solder bumps (Production Example 7) prepared in step c2, solder bumps to the chip with gold bumps (3.0 x 3.0 mm, thickness: 0.5 mm) has formed

i) On a stainless steel plate with a thickness of 5 mm, a glass plate with a thickness of 0.3 mm was placed, and an evaluation chip was placed on the glass plate with a gold bump facing up.

ii) It was arrange|positioned so that the open surface side of the recessed part of the film for solder bump formation faced downward, and the gold bump surface of an evaluation chip and the film for solder bump formation contacted. Furthermore, a 0.3 mm-thick glass plate was placed on the film for solder bump formation, a stainless steel weight was placed on the glass plate, and the film for solder bump formation was brought into close contact with the gold bump.

iii) The stainless steel plate prepared in ii) was placed on a belt conveyor of a formic acid reflow conveyor furnace (Heller Industries Inc. 1936MKV) and flowed at a speed of 40 mm/s. In the conveyor furnace, the sample first passed through a nitrogen gas zone. At this time, oxygen around the sample was removed. Subsequently, it passed through a zone of nitrogen gas heated to 150°C, and also passed through a zone of formic acid gas (4%) at 180°C, and then introduced into a vacuum chamber set at 160°C. After the vacuum chamber was closed, the inside of the chamber was maintained at vacuum for 1 minute, nitrogen gas was introduced to return to atmospheric pressure, and then the sample exited the vacuum chamber, passed through a cooling zone of nitrogen gas atmosphere, and returned to room temperature. The uppermost weight, the glass plate, and the film for solder bump formation were removed in this order. Then, the evaluation chip was immersed in a methanol solution, the fluidized bed was wash-removed, it vacuum-dried (40 degreeC for 60 minutes), and the evaluation chip with solder bump was obtained.

<Evaluation of solder bumps: using formic acid gas>

The evaluation chip obtained through the process f2 was fixed to the pedestal surface for SEM observation, and platinum sputtering was performed on the surface. By SEM, for 30 gold bumps, the number of solder bumps placed on the gold bumps was counted to calculate the average number of solder bumps placed on one gold bump. A result is shown in Table 3. Moreover, the height of the solder bump from the gold bump was measured using the laser microscope (The Olympus Co., Ltd. make, LEXT OLS5000-SAF), and the average value of 100 pieces was computed. A result is shown in Table 4.

Solder bump formation and its evaluation were performed by the method similar to process f2 except having used the film for solder bump formation of Production Examples 8-12 instead of the film for solder bump formation of Production Example 7. Table 4 shows the evaluation results.

Solder bump formation and its evaluation were performed by the method similar to process f2 except having used the film for comparative solder bump formation obtained in Comparative Production Example 1. A result is shown in Table 4.

[Table 4]

In Production Examples 7 to 12, it was possible to form solder bumps on the gold bumps. In particular, compared with the case where the formic acid gas atmosphere was not used (Table 3), the number of solder bumps tends to increase. This is because the surface oxide film of the solder particles in the recess was sufficiently reduced by the flux component contained in the fluidized bed and the formic acid gas, and the organic matter on the surface of the gold pad was also removed with the formic acid gas, so solder bumps were formed on the gold bumps. I think it was easy to become. When the solder bumps obtained using the formic acid gas atmosphere were observed with a microscope and an electron microscope, the spherical distortion was less than that of the solder bumps obtained without using the formic acid gas atmosphere. This is considered to be a spherical shape with little distortion, since air bubbles in the solder bumps are removed and the low molecular weight components of the fluidized phase are sufficiently evaporated as a result of the vacuum in the vacuum chamber after heating.

In Comparative Production Example 1, formation of solder bumps was confirmed on the gold bumps, but compared with Production Examples 7 to 12, the number of bumps tended to be small. Even when the same Comparative Production Example 1 was used, the formation of solder bumps was not observed when the formic acid gas atmosphere was not used. However, when the formic acid gas atmosphere was used, the surface oxide film was removed from the solder particles in some recesses by the formic acid gas atmosphere. and placed on the gold bump in a certain amount. However, since the side of the recess is pressed against the gold bump, it is considered that the formic acid gas does not sufficiently remove the surface oxide film of the solder particles in the recess.

<Production of connection structure>

Step g1: Preparation of the evaluation substrate

Seven types of substrates with gold bumps (70 x 25 mm, thickness: 0.5 mm) shown below were prepared. Further, lead wires for resistance measurement are also formed on these gold bumps.

Substrate D1... Area 100 μm×100 μm, Space 40 μm, Height: 4 μm, Number of bumps 362

Substrate D2... Area 75 μm×75 μm, space 20 μm, height: 4 μm, number of bumps 362

Substrate D3... Area 40 μm×40 μm, space 16 μm, height: 4 μm, number of bumps 362

Substrate D4... Area 20 μm×20 μm, space 7 μm, height: 4 μm, number of bumps 362

Substrate D5... Area 10μm x 10μm, Space 6μm, Height: 3μm, Number of bumps 362

Substrate D6... Area 10μm x 10μm, Space 4μm, Height: 3μm, Number of bumps 362

Substrate D7... Area 5 μm×10 μm, space 3 μm, height: 3 μm, number of bumps 362

Step h1: bonding of electrodes

According to the procedures of i) to iii) shown below, using the evaluation chip with solder bumps produced in step f1, the evaluation board with gold bumps and the solder bumps were connected via the solder bumps.

i) An evaluation board was placed on the lower hot plate of a formic acid reflow furnace (manufactured by Shinko Seiki Co., Ltd., batch type vacuum soldering apparatus) with the gold bumps facing up.

ii) The solder bump surface of the evaluation chip on which the solder bumps were formed was facing down, and the gold bump surface of the evaluation board was placed so that the solder bump was in contact, and fixed so as not to move.

iii) The formic acid vacuum reflow furnace was operated, evacuated, filled with formic acid gas, and the lower hot plate was heated to 180° C. and heated for 5 minutes. Thereafter, after exhausting the formic acid gas by vacuum evacuation, nitrogen substitution was performed, the lower hot plate was returned to room temperature, and the furnace interior was opened to the atmosphere. An appropriate amount of an underfill material (manufactured by Hitachi Chemical Co., Ltd., CEL series) having adjusted viscosity is placed between the evaluation chip and the evaluation substrate, filled with vacuum evacuation, cured at 165° C. for 2 hours, and the bonding structure between the evaluation chip and the evaluation substrate is obtained. made The combination of each material in a bonded structure is as follows.

(1) Chip C1/film/substrate D1 for forming solder bumps

(2) Chip C2/film for forming solder bumps/substrate D2

(3) Chip C3/film for forming solder bumps/substrate D3

(4) Chip C4/film for forming solder bumps/substrate D4

(5) Chip C5/film for forming solder bumps/substrate D5

(6) Chip C6/film for forming solder bumps/substrate D6

(7) Chip C7/film for forming solder bumps/substrate D7

<Evaluation of connection structure>

About a part of the obtained bonded structure, the conduction resistance test and the insulation resistance test were performed as follows.

(Constant resistance test - moisture absorption and heat resistance test)

Conduction resistance between the chip with gold bumps (bump) and the board with gold bumps (bump) The later value was measured about 20 samples, and those average values were computed.

From the obtained average value, conduction|electrical_connection resistance was evaluated according to the following reference|standard. A result is shown in Table 5. Further, it can be said that the conduction resistance is good when the following criteria A or B are satisfied after 1000 hours of the moisture absorption and heat resistance test.

A: The average value of the conduction resistance is less than 2Ω

B: Average value of conduction resistance is 2Ω or more and less than 5Ω

C: The average value of the conduction resistance is 5 Ω or more and less than 10 Ω

D: The average value of the continuity resistance is 10 Ω or more and less than 20 Ω

E: The average value of the conduction resistance is 20 Ω or more

(Continuation Resistance Test - High Temperature Leaving Test)

With respect to the conduction resistance between the chip with gold bumps (bump) and the substrate with gold bumps (bump), the initial value of the conduction resistance and the value after a high temperature exposure test (100, 500, and 1000 hours at a temperature of 100°C), It measured about 20 samples. In addition, after leaving high temperature, the drop impact was applied and the conduction resistance of the sample after a drop impact was measured. The drop impact was generated by screwing the bonded structure to a metal plate and dropping it from a height of 50 cm. After the fall, the DC resistance value was measured in the solder joint portions (4 places) of the chip corner with the greatest impact, and when the measured value increased 5 times or more from the initial resistance, it was considered that fracture had occurred, and evaluation was performed. In addition, in 4 places for each sample, a total of 80 places was measured. A result is shown in Table 6. The solder connection reliability was evaluated as favorable in the case where the following criteria of A or B were satisfied after 20 falls.

A: There were 0 places where the solder joint increased 5 times or more from the initial resistance.

B: The solder joint portions increased by 5 times or more from the initial resistance were 1 or more and 5 or less.

C: The solder joint portions increased by 5 times or more from the initial resistance were 6 or more and 20 or less.

D: There were 21 or more solder joints, which increased 5 times or more from the initial resistance.

(Insulation resistance test)

Regarding the insulation resistance between the chip electrodes, the initial value of the insulation resistance and the value after the migration test (100, 500, and 1000 hours left under conditions of temperature 60°C, humidity 90%, and 20V application) were measured for 20 samples, and the total Among 20 samples, the ratio of the sample used as 10 ⁹ ohms or more in insulation resistance value was computed. From the obtained ratio, insulation resistance was evaluated according to the following reference|standard. A result is shown in Table 7. In addition, it can be said that insulation resistance is favorable when the criteria of following A or B are satisfied after 1000 hours of migration test.

A: 100% of insulation resistance value 10 ⁹ Ω or higher

B: Insulation resistance value 10 ⁹ Ω or more, 90% or more and less than 100%

C: Insulation resistance value 10 ⁹ Ω or more, 80% or more and less than 90%

D: Insulation resistance value 10 ⁹ Ω or more is 50% or more and less than 80%

E: Insulation resistance value 10 ⁹ Ω or more is less than 50%

[Table 5]

[Table 6]

[Table 7]

<Production of film for forming solder bumps>

Process i1: Production of evaluation gas

On a 6-inch silicon wafer, a liquid photosensitive resist (manufactured by Hitachi Chemical Co., Ltd., AH series) was applied to a thickness of 2.3 µm by spin coating. The photosensitive resist on this silicon wafer is exposed and developed, and an opening diameter of 3.1 μmφ, a bottom diameter of 2.0 μmφ, and a depth of 2.3 μm (the bottom diameter of 2.0 μmφ is located in the center of the opening diameter of 3.1 μmφ when the opening is viewed from the top) An evaluation pattern having a concave portion was formed. In addition, one of this evaluation patterns is a size of 20 mm x 20 mm, and the above-mentioned recessed part is arrange|positioned in the 10 mm x 10 mm area of the center. The position of the recessed part is arrange|positioned at the position (X direction pitch, Y direction pitch) relative to the electrode arrangement pattern of the evaluation chip C8 mentioned later, and three alignment marks are also arrange|positioned. This was cut into the size of 20 mm x 20 mm with a dicer, and the base|substrate 1 for evaluation was obtained. The outline|summary of the base|substrate for evaluation is shown in Table 8.

[Table 8]

Bases 2 to 6 for evaluation were prepared by setting the thickness, aperture diameter, and pitch of the photosensitive resist to the values shown in Table 8.

<Preparation of solder particles>

Step j1: Preparation of solder particles

Through steps a1, b1, and c1, films for forming solder bumps having solder particles in the recesses shown in Production Examples 7 to 12 in Table 2 were obtained. The film for solder bump formation obtained by filling the stainless steel vat with isopropyl alcohol was immersed, and the ultrasonic wave of 28 kHz and 600 W was applied for 5 minutes. The solder particles detached from the recesses and dispersed in the isopropyl alcohol solvent. The solvent in which the solder particles were dispersed was left still, and the supernatant was discarded. Thereafter, it was refilled with isopropyl alcohol to sufficiently disperse the solder particles, and then left still. This sedimentation separation operation was performed three times to obtain solder particles (1 to 6) having a uniform particle size. Table 9 shows the outline of the solder particles 1 to 6 .

[Table 9]

(Production Example 25)

Process k1: Placing the fluidizing agent and solder particles

Dodecane and solder particles (1) were placed in a glass bottle with a lid and dispersed by ultrasonic waves. The dispersion liquid was hung on the surface of the base 1 for evaluation of 20 mm x 20 mm fixed on the glass plate, and the surface of the base 1 for evaluation was rubbed with a urethane squeegee, and the solder particles 1 and dodecane were filled in the recesses. The excess solder particles (1) and dodecane on the surface of the evaluation base 1 were wiped off with a clean cloth, and a film for forming solder bumps in which the solder particles (1) and dodecane were disposed in the recesses of the evaluation base 1 was obtained.

[Table 10]

(Production Examples 26-42)

Film 26 for forming solder bumps for evaluation, in which the solder particles and the fluidizing agent were disposed in the recesses in the same manner as in step k1, except that the type of the fluidizing agent, the solder particles, and the base for evaluation were the combinations shown in Table 10. ~42 was obtained. In addition, adipic acid put 20 mass parts of adipic acid with respect to 90 mass parts of dihydroterpineol, mixed well, and set it as the fluidized bed.

<Production of evaluation chip with solder bumps>

Step e2: Preparation of the evaluation chip

Six types of chips with gold bumps (10 mm x 10 mm, thickness: 0.5 mm) shown below were prepared.

Chip C8… Size 8 x 4 μm, pitch in X direction 16 μm, pitch in Y direction 8 μm, height: 3 μm, number of bumps 382000

Chip C9… Size 16μm x 8μm, pitch in X direction 32μm, pitch in Y direction 16μm, height: 5μm, number of bumps 95700

Chip C10… Size 24 μm×12 μm, X-direction pitch 48 μm, Y-direction pitch 24 μm, height: 8 μm, number of bumps 42500

Chip C11... Size 72 μm×36 μm, pitch in X direction 144 μm, pitch in Y direction 72 μm, height: 10 μm, number of bumps 4700

Chip C12… Size 96μm x 48μm, pitch 192μm in X direction, pitch 96μm in Y direction, height: 13μm, number of bumps 2600

Chip C13... Size 140μm x 70μm, pitch in X direction 280μm, pitch in Y direction 140μm, height: 18μm, number of bumps 1200

Moreover, three alignment marks are arrange|positioned at each.

<Formation of solder bumps>

Process f3: Solder bump formation: nitrogen atmosphere

According to the procedures of i) to iii) shown below, solder bumps were formed on the chip with gold bumps (10 mm × 10 mm, thickness: 0.5 mm) using the film 25 for forming solder bumps for evaluation produced in step k1. .

i) On a 30 mm x 30 mm (thickness 0.5 mm) glass plate, the chip|tip C8 was fixed with the gold bump facing up. This was adsorbed and fixed to the stage of a flip-chip bonder (FC3000: Toray product).

ii) The 20 mm x 20 mm evaluation base 1 was picked up by the head for heating and pressurization, the alignment mark was read by the camera, the electrode position of the chip C8 and the recessed part of the evaluation base 1 were made to oppose, and it stored temporarily.

iii) A steerable glass cover into which nitrogen gas enters was prepared. With this glass cover, the whole hotplate was covered, and the hotplate of a hotplate was heated up to 150 degreeC. The sample prepared in ii) was placed on a hot plate, and a stainless steel weight was placed on the uppermost evaluation base 1 and heated in a nitrogen atmosphere for 3 minutes. Then, it removed in order of the uppermost weight and the base|substrate 1 for evaluation. Then, the chip C8 was immersed in a methanol solution, the fluidized bed was wash|cleaned, it vacuum-dried (40 degreeC, 60 minutes), and the chip|tip 25 for evaluation with solder bump was obtained.

<Evaluation of solder bumps: no use of formic acid gas>

The chip 25 for evaluation obtained through the process f1 was fixed to the pedestal surface for SEM observation, and platinum sputtering was performed on the surface. With respect to 300 gold bumps, the number of solder bumps formed on the gold bumps was counted by SEM, the solder bump formation rate was computed, and the following evaluation criteria evaluated. A result is shown in Table 11. Further, it can be said that the evaluation of the solder bump formation rate is favorable when the criteria of A or B are satisfied.

A: The solder bump formation rate is 90% or more

B: Solder bump formation rate 80% or more and less than 90%

C: Solder bump formation rate is 70% or more and less than 80%

D: Solder bump formation rate is 60% or more and less than 70%

E: Solder bump formation rate is less than 60%

Further, the height of the solder bumps from the gold bumps was measured using a laser microscope (manufactured by Olympus Corporation, LEXT OLS5000-SAF), and the average value of 100 pieces was calculated. A result is shown in Table 11.

Next, in place of the film for forming solder bumps for evaluation of Production Example 25, films 26 to 42 for forming solder bumps for evaluation of Production Examples 26 to 42 were used, respectively, at the positions of the gold bumps (electrodes) and the recesses. Solder bump formation and its evaluation were performed by the method similar to the above except having used the corresponding chips C8-13. Table 11 shows the evaluation results.

[Table 11]

In all of the evaluation chips 25 to 42, solder bumps were sufficiently formed on the gold bumps. The solder bumps were formed only on the electrodes, and there were no solder particles between the electrodes. Since the opening face of the concave portion of the film for forming solder bumps is pressed against the electrode surface, the possibility that the molten solder leaks from the electrode surface is low even if there is a fluidized bed, and the solder bumps can be formed stably.

<Formation of solder bumps>

Process f4: Solder bump formation: formic acid atmosphere

Solder bumps were formed and evaluated using the same method as in step f3 except that iii) of step f3 was changed to the following method. Table 12 shows the evaluation results.

iii) The glass plate on which the base 1 for evaluation was mounted on the chip C8 was placed and fixed on the hot plate of a formic acid furnace (manufactured by Shinko Seiki Co., Ltd.), and a stainless steel weight was mounted on the base 1 for evaluation. After vacuum degassing the furnace, it was treated at 150 DEG C for 3 minutes in a formic acid atmosphere, and returned to atmospheric pressure. Then, it removed in order of the uppermost weight and the base|substrate 1 for evaluation. Then, the chip C8 was immersed in a methanol solution, the fluidized bed was wash-removed, it vacuum-dried (40 degreeC for 60 minutes), and the evaluation chip 43 with solder bump was obtained.

[Table 12]

Using the method of step f4, solder bumps were formed by the combinations shown in Table 12, and evaluation chips 44 to 60 were obtained. Table 12 shows the evaluation results performed in the same manner as above.

All of the evaluation chips 43 to 60 were able to form good solder bumps. Since it was set as a reducing atmosphere with formic acid, a favorable result was obtained.

<Formation of solder bumps>

Process f5: Solder bump formation: vacuum pressing

Solder bumps were formed and evaluated in the same manner as in step f3 except that iii) of step f3 was changed to the following method. Table 13 shows the evaluation results.

iii) The glass plate on which the base|substrate 1 for evaluation was mounted on the chip|tip C8 was arrange|positioned on the carrier film of a vacuum pressurization type laminator (MVL-500: manufactured by Nippon Seikosho Co., Ltd.). The upper and lower heating plate temperature was set to 145 degreeC, and it processed with the pressure of 0.5 MPa, and pressurization time of 3 s. Then, the base 1 for evaluation was removed. Then, the chip C8 was immersed in a methanol solution, the fluidized bed was washed and removed, and it vacuum-dried (40 degreeC for 60 minutes), and obtained the chip 61 for evaluation with solder bump. A result is shown in Table 13.

[Table 13]

Using the method of step f5, solder bumps were formed in the combinations shown in Table 13, and evaluation chips 62 to 78 were obtained. Table 13 shows the evaluation results performed in the same manner as above.

In all of the evaluation chips 61 to 78, good solder bumps were able to be formed. By vacuum pressurization, good results were obtained because the pressure was uniformly applied to the surface.

<Production of evaluation chip with solder bumps>

Step e3: Preparation of the evaluation chip

Six types of chips with copper bumps (10 mm x 10 mm, thickness: 0.5 mm) shown below were prepared.

Chip C14... Size 8 x 4 μm, pitch in X direction 16 μm, pitch in Y direction 8 μm, height: 3 μm, number of bumps 382000

Chip C15… Size 16μm x 8μm, pitch in X direction 32μm, pitch in Y direction 16μm, height: 5μm, number of bumps 95700

Chip C16... Size 24 μm×12 μm, X-direction pitch 48 μm, Y-direction pitch 24 μm, height: 8 μm, number of bumps 42500

Chip C17… Size 72 μm×36 μm, pitch in X direction 144 μm, pitch in Y direction 72 μm, height: 10 μm, number of bumps 4700

Chip C18… Size 96μm x 48μm, pitch 192μm in X direction, pitch 96μm in Y direction, height: 13μm, number of bumps 2600

Chip C19… Size 140μm x 70μm, pitch in X direction 280μm, pitch in Y direction 140μm, height: 18μm, number of bumps 1200

Moreover, three alignment marks are arrange|positioned at each.

<Formation of solder bumps>

Process f6: Solder bump formation: vacuum pressing

Solder bumps were formed and evaluated in the same manner as in step f3 except that iii) of step f3 was changed to the following method. Table 14 shows the evaluation results.

iii) The glass plate on which the base 1 for evaluation was mounted on the chip C14 was arrange|positioned on the carrier film of a vacuum pressurization laminator (MVL-500: manufactured by Nippon Seikosho Co., Ltd.). The upper and lower heating plate temperature was set to 150 degreeC, and it processed by the pressure of 0.5 MPa, and pressurization time of 10 s. Then, the base 1 for evaluation was removed. Then, the chip C14 was immersed in a methanol solution, the fluidized bed was wash|cleaned, and it vacuum-dried (40 degreeC for 60 minutes), and the chip 79 for evaluation with solder bump was obtained.

[Table 14]

Using the method of step f6, solder bumps were formed in the combinations shown in Table 14, and evaluation chips 80 to 96 were obtained. Table 14 shows the evaluation results performed in the same manner as above.

Even in the evaluation chips 79 to 96 having Cu bumps (electrodes), good solder bump formation was possible.

<Production of connection structure>

Step g2: Preparation of the evaluation substrate

Six types of substrates with gold bumps (40 x 40 mm, thickness: 0.5 mm) shown below were prepared. The arrangement of the Au bumps is positioned relative to the Au bumps of the chips C8 to C13, and there are three alignment marks for alignment. Further, lead wires for resistance measurement are also formed on these gold bumps.

Substrate D8... Compatible chips: Chip C8/size 8 x 4 μm, pitch in X direction 16 μm, pitch in Y direction 8 μm, height: 3 μm, number of bumps 382000

Substrate D9... Compatible chip: Chip C9/size 16μm x 8μm, pitch in X direction 32μm, pitch in Y direction 16μm, height: 5μm, number of bumps 95700

Substrate D10... Compatible chips: Chip C10/size 24 μm×12 μm, pitch in X direction 48 μm, pitch in Y direction 24 μm, height: 8 μm, number of bumps 42500

Substrate D11... Compatible chips: Chip C11/size 72μm×36μm, pitch 144μm in X direction, pitch 72μm in Y direction, height: 10μm, number of bumps 4700

Substrate D12... Compatible chip: Chip C12/size 96μm×48μm, pitch 192μm in X direction, pitch 96μm in Y direction, height: 13μm, number of bumps 2600

Substrate D13... Compatible chip: Chip C13/size 140μm×70μm, pitch 280μm in X direction, pitch 140μm in Y direction, height: 18μm, number of bumps 1200

Step h2: bonding of electrodes

According to the procedures of i) to iii) shown below, using the evaluation chip with solder bumps produced in step f5, the evaluation board with gold bumps and the solder bumps were connected via the solder bumps.

i) The board|substrate on which the gold bump was formed was fixed to the stage of the flip-chip bonder (FC3000: Toray Corporation make). The evaluation chip in which the solder bump was formed was picked up by the head for heating and pressurization, and it arrange|positioned at the position where the gold bump mutually opposes from the alignment mark.

ii) The substrate on which the evaluation chip was mounted was placed on the lower hot plate of a formic acid reflow furnace (manufactured by Shinko Seiki Co., Ltd., batch type vacuum soldering apparatus), and a stainless steel weight was placed on the evaluation chip.

iii) The formic acid vacuum reflow furnace was operated, evacuated, filled with formic acid gas, and the lower hot plate was heated to 150° C. and heated for 5 minutes. Thereafter, the formic acid gas was discharged by vacuum evacuation, followed by nitrogen replacement, the lower hot plate was returned to room temperature, and the furnace interior was opened to the atmosphere. An appropriate amount of an underfill material (manufactured by Hitachi Chemical Co., Ltd., CEL series) having adjusted viscosity is placed between the evaluation chip and the evaluation substrate, filled with vacuum evacuation, and cured at 125°C for 4 hours to obtain a joint structure between the evaluation chip and the evaluation substrate. made

<Evaluation of connection structure>

About a part of the obtained bonded structure, the conduction resistance test and the insulation resistance test were done similarly to process:h1. The results are shown in Tables 15, 16 and 17.

[Table 15]

[Table 16]

[Table 17]

<Production of connection structure>

Step g3: Preparation of the evaluation substrate

Six types of substrates with copper bumps (40 x 40 mm, thickness: 0.5 mm) shown below were prepared. The Cu bumps are arranged at positions relative to the Cu bumps of the chips C14 to C19, and there are three alignment marks to enable alignment. In addition, the lead wiring for resistance measurement is also formed in these Cu bumps.

Substrate D14... Compatible chips: Chip C14/size 8 x 4 μm, pitch in X direction 16 μm, pitch in Y direction 8 μm, height: 3 μm, number of bumps 382000

Substrate D15... Compatible chips: Chip C15/size 16μm x 8μm, pitch in X direction 32μm, pitch in Y direction 16μm, height: 5μm, number of bumps 95700

Substrate D16... Compatible chips: Chip C16/size 24μm x 12μm, pitch in X direction 48μm, pitch in Y direction 24μm, height: 8μm, number of bumps 42500

Substrate D17... Compatible chip: Chip C17/size 72μm×36μm, pitch 144μm in X direction, pitch 72μm in Y direction, height: 10μm, number of bumps 4700

Substrate D18... Compatible chips: Chip C18/size 96μm×48μm, pitch 192μm in X direction, pitch 96μm in Y direction, height: 13μm, number of bumps 2600

Substrate D19... Compatible chip: Chip C19/size 140μm×70μm, pitch in X direction 280μm, pitch in Y direction 140μm, height: 18μm, number of bumps 1200

Step h3: bonding of electrodes

According to the procedures of i) to iii) shown below, using the evaluation chip with solder bumps produced in step f6, the evaluation board with copper bumps and the solder bumps were connected via the solder bumps.

i) The evaluation substrate was set in a spin coater (manufactured by SC-308S Co., Ltd. Oshigane Co., Ltd.), and 0.5 ml of flux (WHS-003C: manufactured by Arakawa Chemical Industries Co., Ltd.) was spread on the surface on which the Cu bumps were formed. It was processed for 10 s at the rotation speed of 500 rpm, and then for 3 s at 1000 rpm to form a thin flux layer.

ii) The evaluation substrate was fixed to the stage of a flip chip bonder (FC3000: manufactured by Toray Corporation). The evaluation chip in which the solder bump was formed was picked up by the head for heating and pressurization, and it arrange|positioned at the position where the bump mutually opposes from the alignment mark. The substrate on which the evaluation chip was mounted was placed on the lower hot plate of a formic acid reflow furnace (manufactured by Shinko Seiki Co., Ltd., batch type vacuum soldering apparatus), and a stainless steel weight was placed on the evaluation chip.

iii) The formic acid vacuum reflow furnace was operated, and after evacuation, the formic acid gas was filled, and the lower hot plate was heated to 160° C. and heated for 3 minutes. Thereafter, after exhausting the formic acid gas by vacuum evacuation, nitrogen substitution was performed, the lower hot plate was returned to room temperature, and the furnace interior was opened to the atmosphere. An appropriate amount of an underfill material (manufactured by Hitachi Chemical Co., Ltd., CEL series) having adjusted viscosity is placed between the evaluation chip and the evaluation substrate, filled with vacuum evacuation, cured at 125°C for 4 hours, and the bonding structure between the evaluation chip and the evaluation substrate is obtained. made

<Evaluation of connection structure>

About a part of the obtained bonded structure, the conduction resistance test and the insulation resistance test were done similarly to process:h1. The results are shown in Tables 18, 19 and 20.

[Table 18]

[Table 19]

[Table 20]

Even when Cu electrodes were joined through solder bumps formed on the Cu electrodes, stable connection characteristics were exhibited.

One… solder particles
1A… solder bump
1B… solder layer
2… Board
3… electrode
4… other substrate
5… other electrode
10… Solder bump forming member
20… Electrode substrate with solder bumps
30… connection structure
60… gas
62... recess
111… Solder Particles
F… glidant
600… gas
601… base layer
602… concave layer

Claims (18)

a base having a plurality of recesses, and solder particles and a fluidizing agent in the recesses;
A member for forming solder bumps, wherein the solder particles have an average particle diameter of 1 to 35 µm and a CV value of 20% or less. The method according to claim 1,
The member for solder bump formation in which the said fluidizing agent contains at least 1 sort(s) selected from the group which consists of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, benzoic acid, and malic acid. The method according to claim 1 or 2,
A member for forming a solder bump, wherein a flat portion is formed on a part of a surface of the solder particle. 4. The method according to any one of claims 1 to 3,
A member for forming solder bumps, wherein a distance between adjacent concave portions is 0.1 times or more of an average particle diameter of the solder particles. A pre-process of preparing a base having a plurality of recesses, solder particles, and a fluidizing agent;
The manufacturing method of the member for solder bump formation provided with the arrangement process of arrange|positioning the said solder particle and the said fluidizing agent in the said recessed part. 6. The method of claim 5,
The manufacturing method of the said solder particle whose average particle diameter is 1-35 micrometers, and CV value is 20 % or less. A preparation step of preparing a base having a plurality of concave portions and solder fine particles;
a receiving step of accommodating at least a portion of the solder fine particles in the concave portion;
a fusion step of fusing the solder fine particles accommodated in the concave portion to form solder particles in the concave portion;
and an injection step of disposing a fluidizing agent in the recesses in which the solder particles are formed. 8. The method of claim 7,
The manufacturing method of the said solder particle whose average particle diameter is 1-35 micrometers, and CV value is 20 % or less. 9. The method according to claim 7 or 8,
The manufacturing method according to claim 1, wherein the CV value of the solder fine particles exceeds 20%. 10. The method according to any one of claims 7 to 9,
and a reducing step of exposing the solder fine particles accommodated in the recessed portion to a reducing atmosphere before the fusion step. 11. The method according to any one of claims 7 to 10,
In the fusion step, the solder fine particles are fused in a reducing atmosphere. A preparatory step of preparing a substrate having the member for forming a solder bump according to any one of claims 1 to 4, and a plurality of electrodes;
an arrangement step of facing and contacting a surface of the member for forming solder bumps with the surface having the concave portion and the surface of the substrate having the electrode;
A method for manufacturing an electrode substrate with solder bumps, comprising a heating step of heating the solder particles to a temperature equal to or higher than the melting point of the solder particles. 13. The method of claim 12,
In the heating step, the solder particles are heated to a temperature equal to or higher than the melting point of the solder particles while the member for forming solder bumps and the substrate are brought into contact with each other in a pressurized state. 14. The method of claim 12 or 13,
The manufacturing method which further comprises a reducing process of exposing the said solder particle to a reducing atmosphere before the said arrangement|positioning process. 15. The method according to any one of claims 12 to 14,
and a reduction step of exposing the solder particles to a reducing atmosphere after the arrangement step and before the heating step. 16. The method according to any one of claims 12 to 15,
In the heating step, the solder particles are heated to a temperature equal to or higher than the melting point of the solder particles in a reducing atmosphere. 17. The method according to any one of claims 12 to 16,
The manufacturing method which further comprises a removal process which removes the said solder bump formation member from the said board|substrate after the said heating process. 18. The method of claim 17,
The manufacturing method further comprising a washing process of removing the said solder particle which is not bonded to the said electrode after the said removal process.

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