WO2021131897A1 - はんだバンプ形成用部材、はんだバンプ形成用部材の製造方法、及びはんだバンプ付き電極基板の製造方法 - Google Patents

はんだバンプ形成用部材、はんだバンプ形成用部材の製造方法、及びはんだバンプ付き電極基板の製造方法 Download PDF

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Publication number
WO2021131897A1
WO2021131897A1 PCT/JP2020/046731 JP2020046731W WO2021131897A1 WO 2021131897 A1 WO2021131897 A1 WO 2021131897A1 JP 2020046731 W JP2020046731 W JP 2020046731W WO 2021131897 A1 WO2021131897 A1 WO 2021131897A1
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WIPO (PCT)
Prior art keywords
solder
substrate
particles
recess
bumps
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PCT/JP2020/046731
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English (en)
French (fr)
Japanese (ja)
Inventor
純一 畠
邦彦 赤井
勝将 宮地
芳則 江尻
Original Assignee
昭和電工マテリアルズ株式会社
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Application filed by 昭和電工マテリアルズ株式会社 filed Critical 昭和電工マテリアルズ株式会社
Priority to JP2021567299A priority Critical patent/JP7661891B2/ja
Priority to CN202080097284.4A priority patent/CN115152007A/zh
Priority to KR1020227023758A priority patent/KR20220122663A/ko
Publication of WO2021131897A1 publication Critical patent/WO2021131897A1/ja
Priority to JP2025060972A priority patent/JP2025092693A/ja

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/74—Apparatus for manufacturing arrangements for connecting or disconnecting semiconductor or solid-state bodies
    • H01L24/741—Apparatus for manufacturing means for bonding, e.g. connectors
    • H01L24/742—Apparatus for manufacturing bump connectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the groups H01L21/18 - H01L21/326 or H10D48/04 - H10D48/07 e.g. sealing of a cap to a base of a container
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/10—Bump connectors ; Manufacturing methods related thereto
    • H01L24/11—Manufacturing methods
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/10—Bump connectors ; Manufacturing methods related thereto
    • H01L24/12—Structure, shape, material or disposition of the bump connectors prior to the connecting process
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L24/81—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a bump connector
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/11—Manufacturing methods
    • H01L2224/118—Post-treatment of the bump connector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/81—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a bump connector
    • H01L2224/81009—Pre-treatment of the bump connector or the bonding area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/81—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a bump connector
    • H01L2224/81053—Bonding environment
    • H01L2224/81091—Under pressure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/81—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a bump connector
    • H01L2224/81053—Bonding environment
    • H01L2224/81095—Temperature settings
    • H01L2224/81096—Transient conditions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/81—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a bump connector
    • H01L2224/812—Applying energy for connecting
    • H01L2224/81201—Compression bonding
    • H01L2224/81203—Thermocompression bonding, e.g. diffusion bonding, pressure joining, thermocompression welding or solid-state welding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/81—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a bump connector
    • H01L2224/81909—Post-treatment of the bump connector or bonding area
    • H01L2224/8191—Cleaning, e.g. oxide removal step, desmearing

Definitions

  • the present invention relates to a solder bump forming member, a method for manufacturing a solder bump forming member, and a method for manufacturing an electrode substrate with solder bumps.
  • solder ball arrangement sheet is known (see, for example, Patent Document 1).
  • a method for manufacturing a solder bump forming sheet in which a solder ball or a solder powder is held at a predetermined position including the following steps is known (see, for example, Patent Document 2).
  • A. Prepare a sheet on one side with a number of recesses in place, the bottom of which is made of an adhesive;
  • B. Each recess of the sheet is filled with solder powder, and the adhesive on the bottom of the recess adheres and holds the solder powder;
  • the solder powder that is not held by the adhesive is removed from the sheet, and D.I. Cover the solder powder in the recesses of the sheet.
  • a method of forming solder bumps on an electrode by transferring a solder ball arranged in a groove to an adhesive roll surface and further transferring the solder ball to an adhesive on an electrode is known (for example, Patent Documents). 3).
  • the transfer sheet and the manufacturing method shown in Patent Documents 1 and 2 require an adhesive layer for holding the solder particles. Therefore, the adhesive layer component may be softened, melted, and decomposed to become a contaminant by heating above the melting point of the solder to melt and coalesce the solder, and further to transfer the solder onto the electrode.
  • the presence of contaminants between the solder and the electrodes may hinder the stable formation of solder bumps.
  • the substrate and semiconductor package on which the electrodes are formed are exposed to the cleaning liquid, resulting in an increase in processes, defects in the substrate / semiconductor package, and poor cleaning. There is a risk that problems will occur.
  • the adhesive component may remain on the surface of the solder balls and cause a problem in joining. Further, the thickness of the pressure-sensitive adhesive and the unevenness of the surface of the pressure-sensitive adhesive can be controlled when the size of the solder ball is about 100 ⁇ m, but it becomes more difficult as the size becomes smaller as 50 ⁇ m and 30 ⁇ m. Therefore, if solder balls (particles) having a size of less than 30 ⁇ m are transferred and moved via an adhesive, it becomes difficult to increase the transfer rate.
  • the present invention has been made in view of the above circumstances, and manufactures a connection structure having excellent insulation reliability and conduction reliability even if the connection points of circuit members to be electrically connected to each other are minute. It is an object of the present invention to provide a member for forming a solder bump 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 includes a substrate having a plurality of recesses, solder particles and a fluidizing agent in the recesses, and the average particle size of the solder particles is 1 to 35 ⁇ m. V.
  • the present invention relates to a solder bump forming member having a value of 20% or less.
  • the solder bump forming member is useful for manufacturing a connection structure having excellent insulation reliability and conduction reliability even if the connection points of the circuit members to be electrically connected to each other are minute.
  • the fluidizing agent may include at least one selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, benzoic acid, and malic acid.
  • a flat surface portion may be formed on a part of the surface of the solder particles.
  • the distance between adjacent recesses may be 0.1 times or more the average particle size of the solder particles.
  • One aspect of the present invention includes a substrate having a plurality of recesses, a pre-step of preparing solder particles and a fluidizing agent, and an arranging step of arranging the solder particles and the fluidizing agent in the recesses, for forming solder bumps.
  • the present invention relates to a manufacturing method of a member.
  • One aspect of the present invention is to fuse a preparatory step for preparing a substrate having a plurality of recesses and solder fine particles, a storage step for storing at least a part of the solder fine particles in the recesses, and a solder fine particles housed in the recesses.
  • the present invention relates to a method for manufacturing a solder bump forming member, comprising a fusion step of forming solder particles in the recesses and an injection step of arranging a fluidizing agent in the recesses in which the solder particles are formed.
  • the average particle size of the solder particles is 1 to 35 ⁇ m, and C.I. V. The value may be 20% or less.
  • C.I. V. In one aspect of the method for manufacturing a member for forming a solder bump, C.I. V. The value may exceed 20%.
  • One aspect of the method for manufacturing the solder bump forming member may further include a reduction step of exposing the solder fine particles contained in the recesses to a reducing atmosphere before the fusion step.
  • the solder fine particles may be fused in a reducing atmosphere in the fusion step.
  • One aspect of the present invention is a preparatory step for preparing the solder bump forming member and a substrate having a plurality of electrodes, and a surface having a recess of the solder bump forming member and a surface having electrodes of the substrate are opposed to each other.
  • the present invention relates to a method for manufacturing an electrode substrate with solder bumps, which comprises an arrangement step of contacting the solder particles and a heating step of heating the solder particles to a temperature equal to or higher than the melting point of the solder particles.
  • the solder particles may be heated to a temperature equal to or higher than the melting point of the solder particles while contacting the solder bump forming member and the substrate in a pressurized state.
  • 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 placement 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 placement step and before the heating step.
  • 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 method for manufacturing an electrode substrate with solder bumps may further include a removal step of removing the solder bump forming member from the substrate after the heating step.
  • One aspect of the method for manufacturing an electrode substrate with solder bumps may further include a cleaning step of removing solder particles that are not bonded to the electrodes after the removal step.
  • a member and a method for manufacturing the member can be provided. Further, according to the present invention, it is possible to provide a method for manufacturing an electrode substrate with solder bumps using the member.
  • FIG. 1 is a cross-sectional view schematically showing a solder bump forming member according to an embodiment.
  • FIG. 2A is a view of the solder particles viewed from the side opposite to the opening of the recess in FIG. 1, and
  • FIG. 2B is a quadrangle circumscribing the projected image of the solder particles created by two pairs of parallel lines. It is a figure which shows the distance X and Y (where Y ⁇ X) between the opposite sides in the case of.
  • FIG. 3A is a plan view schematically showing an example of the substrate, and FIG. 3B is a cross-sectional view taken along the line Ib-Ib of FIG. 3A.
  • FIG. 4 (a) to 4 (h) are cross-sectional views schematically showing an example 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 contained in the recesses of the substrate.
  • 6 (a) and 6 (b) are cross-sectional views schematically showing an example of a manufacturing process of an electrode substrate with solder bumps.
  • 7 (a) and 7 (b) are cross-sectional views schematically showing an example of a manufacturing process of the connection structure.
  • FIG. 8 is a cross-sectional view schematically showing an example of the substrate.
  • each component in the composition means the total amount of the plurality of substances present in the composition when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified.
  • the numerical range indicated by using "-" indicates a range including the numerical values before and after "-" as the minimum value and the maximum value, respectively.
  • the upper limit value or the lower limit value of the numerical range of one step may be replaced with the upper limit value or the lower limit value of the numerical range of another step.
  • the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.
  • solder bump forming member includes a substrate having a plurality of recesses, solder particles and a fluidizing agent in the recesses, and the average particle size of the solder particles is 1 to 35 ⁇ m. V. The value is 20% or less.
  • FIG. 1 is a cross-sectional view schematically showing a solder bump forming member according to an embodiment.
  • the solder bump forming member 10 includes a substrate 60 having a plurality of recesses 62, and solder particles 1 and a fluidizing agent F in the recesses 62.
  • one solder particle 1 is arranged so as to be arranged in a horizontal direction (horizontal direction in FIG. 1) in a state of being separated from one adjacent solder particle 1.
  • the solder particles 1 may be in contact with the side surface and / or the bottom surface thereof in the recess 62.
  • the fluidizing agent F may be present between the solder particles 1 and the bottom surface of the recess 62.
  • the solder bump forming member may be in the form of a film (solder bump forming film), sheet form (solder bump forming sheet), or the like.
  • solder particles The average particle size of the solder particles 1 is, for example, 35 ⁇ m or less, preferably 30 ⁇ m or less, 25 ⁇ m or less, 20 ⁇ m or less, or 15 ⁇ m or less.
  • the average particle size of the solder particles 1 is, for example, 1 ⁇ m or more, preferably 2 ⁇ m or more, more preferably 3 ⁇ m or more, and further preferably 5 ⁇ m or more.
  • the average particle size of the solder particles 1 can be measured by using various methods according to the size. For example, a dynamic light scattering method, a laser diffraction method, a centrifugal sedimentation method, an electrical detection band method, a resonance type mass measurement method, or the like can be used. Further, a method of measuring the particle size from an image obtained by an optical microscope, an electron microscope, or the like can be used. Specific devices include a flow-type particle image analyzer, a microtrack, a Coulter counter, and the like.
  • the average particle diameter of the solder particles 1 is the diameter equivalent to the projected area circle (a circle having an area equal to the projected area of the particles) when the solder particles 1 are observed from a direction perpendicular to the main surface of the solder bump forming member 10. Diameter).
  • C. of solder particles 1 V The value is preferably 20% or less, more preferably 10% or less, still more preferably 7% or less, from the viewpoint of achieving more excellent conductivity reliability and insulation reliability.
  • the lower limit of the value is not particularly limited.
  • C.I. V. The value may be 1% or more, and may be 2% or more.
  • FIG. 2A is a view of the solder particles 1 viewed from the side opposite to the opening of the recess 62 in FIG.
  • the solder particles 1 have a shape in which a flat surface portion 11 having a diameter A is formed on a part of the surface of a sphere having a diameter B.
  • the solder particles 1 shown in FIGS. 1 and 2A have a flat surface portion 11 because the bottom portion of the recess 62 is flat, but when the bottom portion of the recess 62 has a shape other than a flat surface, the shape of the bottom portion is formed. It will have a surface with a different shape corresponding to.
  • a flat surface portion 11 may be formed on a part of the surface of the solder particles 1, and at this time, the surface other than the flat surface portion 11 is preferably spherical crown-shaped. That is, the solder particles 1 may have a flat surface portion 11 and a spherical crown-shaped curved surface portion.
  • the ratio (A / B) of the diameter A of the flat surface 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), and is 0. It may be 1 to 0.9.
  • the flat surface portion 11 and the bottom surface of the recess 62 may be in contact with each other. As shown in FIG.
  • the solder particles 1 since the solder particles 1 have the flat surface portion 11 and the flat surface portion and the bottom surface of the recess are in contact with each other, the solder particles 1 are less likely to be detached from the solder bump forming member 10. ..
  • the flat surface portion may also be generated at a portion where the inner wall portion of the recess 62 and the solder particles 1 are in contact with each other.
  • the flat surface portion 11 is used. It does not necessarily have to be in contact with the bottom surface of the recess 62.
  • the ratio of Y to X (Y).
  • / X) may be more than 0.8 and less than 1.0 (0.8 ⁇ Y / X ⁇ 1.0), and may be 0.9 or more and less than 1.0.
  • solder particles 1 can be said to be particles closer to a true sphere. Since the solder particles 1 are close to a true sphere, the contact between the solder particles 1 and the electrodes is less likely to be uneven, and a stable connection tends to be obtained.
  • FIG. 2B is a diagram showing distances X and Y (where Y ⁇ X) between opposite sides when a quadrangle circumscribing the projected image of the solder particles is created by two pairs of parallel lines.
  • a quadrangle circumscribing the projected image of the solder particles is created by two pairs of parallel lines.
  • an arbitrary particle is observed with a scanning electron microscope to obtain a projected image.
  • Two pairs of parallel lines are drawn with respect to the obtained projected image, and the pair of parallel lines are arranged at the position where the distance between the parallel lines is the minimum, and the other pair of parallel lines are arranged at the position where the distance between the parallel lines is the maximum.
  • Find the Y / X of the particle This operation is performed on 300 solder particles, the average value is calculated, and the Y / X of the solder particles is obtained.
  • the solder particles 1 may contain tin or a tin alloy.
  • tin alloy for example, In—Sn alloy, In—Sn—Ag alloy, Sn—Au alloy, Sn—Bi alloy, Sn—Bi—Ag alloy, Sn—Ag—Cu alloy, Sn—Cu alloy and the like are used. be able to. Specific examples of these tin alloys include the following examples.
  • the solder particles may contain indium or an indium alloy.
  • the indium alloy for example, an In—Bi alloy, an In—Ag alloy, or the like can be used. Specific examples of these indium alloys include the following examples. -In-Bi (In66.3% by mass, Bi33.7% by mass, melting point 72 ° C.) -In-Bi (In33.0% by mass, Bi67.0% by mass, melting point 109 ° C) -In-Ag (In97.0% by mass, Ag3.0% by mass, melting point 145 ° C)
  • the tin alloy or indium alloy can be selected according to the application (temperature at the time of connection) of the solder particles 1.
  • an In—Sn alloy or a Sn—Bi alloy may be adopted, and in this case, the solder particles can be fused at 150 ° C. or lower.
  • a material having a high melting point such as Sn—Ag—Cu alloy or Sn—Cu alloy is used, high reliability can be maintained even after being left at a high temperature.
  • the solder particles 1 may contain one or more selected from Ag, Cu, Ni, Bi, Zn, Pd, Pb, Au, P and B.
  • Ag or Cu may be contained 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 electrodes is further improved, so that better conduction reliability can be obtained. It becomes easy to obtain.
  • the Cu content of the solder particles 1 is, for example, 0.05 to 10% by mass, and may be 0.1 to 5% by mass or 0.2 to 3% by mass.
  • the Cu content is 0.05% by mass or more, it becomes easy to achieve better solder connection reliability.
  • the solder particles 1 have a low melting point and excellent wettability, and as a result, the connection reliability of the joint portion by the solder particles 1 tends to be good.
  • the Ag content of the solder particles 1 is, for example, 0.05 to 10% by mass, and may be 0.1 to 5% by mass or 0.2 to 3% by mass.
  • the Ag content is 0.05% by mass or more, it becomes easy to achieve better solder connection reliability.
  • the Ag content is 10% by mass or less, the solder particles 1 have a low melting point and excellent wettability, and as a result, the connection reliability of the joint portion by the solder particles 1 tends to be good.
  • the fluidizing agent F has a function of flowing as a fluid phase during reflow and pushing out the solder particles 1 from the recess 62 toward the electrode side.
  • the fluidizing agent F may be a flux, an organic solvent, or the like. The flux has the effect of dissolving the oxides on the surface of the solder particles and the surface of the electrode to improve the wettability of the solder on the electrode.
  • the boiling point of the fluidizing agent F may be higher than the melting point of the solder.
  • 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 recess, and the solder particles also flow as the fluidizing agent F flows. To do.
  • the flow of the fluidizing agent F and the solder particles facilitates contact between the electrode surface and the solder particles, and as a result, the formation of solder bumps is promoted.
  • the solder bumps are formed on the electrodes when the heating temperature is at least 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. It becomes easy to be formed.
  • the heating temperature is raised above the boiling point of the fluidizing agent F after the solder bumps are sufficiently formed, the residue derived from the fluidizing agent F on the surface of the substrate and the surface of the electrode can be reduced.
  • Various organic solvents that can be used for the fluidizing agent F include cyclohexane (boiling point: 80 ° C.), cycloheptane (boiling point: 118 ° C.), cyclooctane (boiling point: 149 ° C.), heptane (boiling point: 98 ° C.), and octane (boiling point: boiling point).
  • Nonan (boiling point: 150 ° C), Decane (boiling point: 174 ° C), Undecane (boiling point: 196 ° C), Dodecan (boiling point: 215 ° C), Tridecane (boiling point: 234 ° C), Tetradecane (boiling point: 254 ° C) ), Pentadecane (boiling point: 269 ° C), hexadecane (boiling point: 287 ° C), heptadecane (boiling point: 302 ° C), octadecane (boiling point: 317 ° C), nonadecan (boiling point: 330 ° C) and other aliphatic hydrocarbons can be used.
  • These aliphatic hydrocarbons are non-polar and do not have a reducing function for solder and metals used for electrodes such as Au and Cu, but can be appropriately selected as a solvent having a boiling point equal to or higher than the melting point of solder, and can be appropriately selected by heating. It has the function of flowing the solder particles and bringing the solder particles into contact with the electrode surface.
  • Examples of various organic solvents that can be used for the fluidizing agent F include pentanol, hexanol, heptanol, octanol, decanol, ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, ⁇ -terpineol, isobornylcyclohexanol (MTPH) and the like.
  • Monovalent and polyhydric alcohols 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 Ethers such as propylene glycol butyl ether, dipropylene glycol dimethyl ether, triprop
  • Examples of 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, and hexyl mercaptan. And dodecyl mercaptan.
  • Examples of mercaptans having a cycloalkyl group having 5 to 7 carbon atoms include cyclopentyl mercaptan, cyclohexyl mercaptan and cycloheptyl mercaptan.
  • Other examples of the organic solvent include alicyclic amines such as monoalkylamines, dialkylamines, trialkylamines, alkanolamines, cyclohexylamines and dicyclohexylamines, and aromatic amines such as diphenylamines and triphenylamines.
  • examples of the organic solvent include ethylene diethanolamine, n-butyl diethanolamine, diethanolamine, N, N-bis (2-hydroxyethyl) isopropanolamine and the like.
  • a glycol ether-based solvent can also be used.
  • the solvent having a boiling point of 200 ° C. or lower include dipropylene glycol monomethyl ether, propylene glycol monobutyl ether, diethylene glycol dimethyl ether, ethylene glycol monoallyl ether, and ethylene glycol monoisopropyl ether. Solvents having a boiling point exceeding 200 ° C.
  • glycol monohexyl ether examples include ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, diethylene glycol dibutyl ether, and triethylene.
  • Glycolbutylmethyl ether, tetraethylene glycol dimethyl ether and the like can be mentioned.
  • a flux that is generally used for solder bonding or the like can be used.
  • the flux can be appropriately selected according to the composition of the solder particles, the melting point, the surface condition, the heating / atmosphere conditions at the time of transfer, and the like.
  • 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, pine fat and the like can be mentioned. These may be used alone or in combination of two or more.
  • Examples of the molten salt include ammonium chloride.
  • Examples of the organic acid include lactic acid, citric acid, stearic acid, glutamic acid, glutaric acid and the like.
  • Examples of the organic acid that can be used for the flux include an organic acid having 8 to 16 carbon atoms.
  • Examples of organic acids having 8 to 16 carbon atoms include capric acid, methylheptanic acid, ethylhexanoic acid, propylpentanoic acid, pelargonic acid, methyloctanoic acid, ethylheptanoic acid, propylhexanoic acid, capric acid, methylnonanoic acid and ethyl.
  • Saturated fatty acids Saturated fatty acids; octenoic acid, nonenic acid, methylnonenic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, myristoleic acid, pentadecenoic acid, hexadecenoic acid, palmitreic acid, sapienoic acid and other unsaturated fatty acids; terephthal Aromas such as acid, pyromellitic acid, o-phenoxy benzoic acid, methyl benzoic acid, ethyl benzoic acid, propyl benzoic acid, butyl benzoic acid, pentyl benzoic acid, hexyl benzoic acid, heptyl benzoic acid, octyl benzoic acid, nonyl benzoic acid
  • Group carboxylic acids include.
  • pine fat include activated pine fat and non-activated pine fat.
  • Pine fat is a rosin whose main component is abietic acid.
  • the melting point of the flux may be 50 ° C. or higher, 70 ° C. or higher, or 80 ° C. or higher.
  • the melting point of the flux may be 200 ° C. or lower, 160 ° C. or lower, 150 ° C. or lower, or 140 ° C. or lower.
  • the melting point range of the flux may be 80 to 190 ° C. and may be 80 to 140 ° C. or lower.
  • Fluxes 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), pimeric acid (melting point 104 ° C), and suberic acid (melting point 104 ° C).
  • Dicarboxylic acids such as 142 ° C., benzoic acid (melting point 122 ° C.), malic acid (melting point 130 ° C.) and the like can be mentioned.
  • the fluidizing agent may include at least one selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, benzoic acid, and malic acid.
  • the amount of the fluidizing agent F present in the recess 62 is not particularly limited, but is 1 to 50 parts by mass with respect to 100 parts by mass of the solder particles 1 from the viewpoint of easily obtaining an appropriate fluidizing action, flux effect, and the like. It may be 1 to 20 parts by mass, and may be 20 to 50 parts by mass.
  • the fluidizing agent F may be a mixture with a solvent or a resin material. As the solvent, the above-mentioned various organic solvents can be used. In the case of a mixture, the concentration of the fluidizing agent F can be appropriately adjusted according to the solder particles 1.
  • the softening point or melting point may be adjusted so that the fluidity of the mixture is increased by heating. If the softening point or melting point is higher than room temperature, the solder particles 1 are less likely to fall out of the recess 62 at room temperature, and can be easily handled before the solder bump forming step.
  • the solvent constituting the mixture include high boiling point solvents and the like. The high boiling point solvent does not easily remain on the electrode because it volatilizes by reheating after the solder particles 1 are made to flow on the electrode.
  • an alcohol solvent or the like can be used. If it is an alcohol solvent, reducing property can be exhibited.
  • the material constituting the substrate 60 for example, an inorganic material such as silicon, various ceramics, glass, a metal such as stainless steel, and an organic material such as various resins can be used.
  • the substrate 60 may be a material having heat resistance that does not deteriorate at the melting temperature of the solder fine particles.
  • the substrate 60 may be made of a material having heat resistance that does not deform even at the temperature at which the solder fine particles are melted.
  • the substrate 60 may be a material that does not change by alloying with a material constituting the solder fine particles or by reacting with the material.
  • the recess 62 of the substrate 60 can be formed by a known method such as a cutting method, a photolithography method, or an imprint method.
  • a cutting method such as a cutting method, a photolithography method, or an imprint method.
  • the recess 62 having an accurate size can be formed in a short process.
  • the surface of the substrate 60 may have a coating layer.
  • the coating layer may be a material that is difficult or not alloyed with the material constituting the solder fine particles.
  • an inorganic substance or an organic substance can be used as the coating layer.
  • the coating layer includes 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 and graphite, and fluororesins. Highly heat-resistant resin such as polyimide can be used.
  • the coating layer may have a role of adjusting the wettability with the solder. By providing the coating layer on the surface of the substrate 60, the wettability with the solder can be appropriately adjusted according to the purpose of use.
  • the coating layer As a method for forming the coating layer, laminating, solution dipping, coating, painting, impregnation, sputtering, plating, etc. can be used.
  • the material of the substrate 60 may be an electrode for transferring the solder particles and a material having similar or the same physical characteristics as the substrate on which the electrode is formed. For example, if the materials have a similar coefficient of thermal expansion (CTE) or the same material, misalignment is unlikely to occur during transfer of solder particles.
  • CTE coefficient of thermal expansion
  • the substrate 60 may be provided with an alignment mark. This alignment mark should be readable by the camera. There may also be an alignment mark on the substrate side having the electrodes. By providing the alignment mark of the base 60 and the substrate having the electrode, when the solder particles are transferred onto the electrode, the alignment mark on the base 60 and the substrate having the electrode are provided by the camera mounted on the alignable device. By reading the alignment mark, it is possible to accurately grasp the position of the recess 62 having the solder particles and the position of the electrode that transfers the solder particles. Further, by providing the alignment mark of the substrate 60 and the substrate having the electrode, the solder particles can be transferred onto the electrode with high positional accuracy.
  • the substrate 60 may be made of an organic material.
  • the organic material may be a polymer material, and thermoplastic, thermosetting, photocurable materials and the like can be used.
  • an organic material By using an organic material, the range of choice of physical properties is widened, so that it is easy to form the substrate 60 according to the purpose.
  • the substrate 60 (including the recess 62) can be easily bent or stretched.
  • various methods can be used for forming the recess 62. As a method for forming the recess 62, imprint, photolithography, cutting, laser machining, or the like can be used.
  • a mold having a desired shape can be pressed against a substrate 60 made of an organic material to form an arbitrary shape on the surface.
  • a concave portion 62 having a desired pattern can be formed.
  • a photocurable resin can be used to form the recess 62, and when the photocurable resin is applied to the mold (mold), exposed, and then the mold (mold) is peeled off, a substrate 60 having the recess 62 is formed. it can.
  • the recess 62 can be formed by a drill or the like.
  • the substrate may be composed of a plurality of organic materials. Further, the substrate may have a plurality of layers, and the plurality of layers may be made of different organic materials.
  • the organic material may be a polymer material, and thermoplastic, thermosetting, photocurable materials and the like can be used.
  • the substrate has two layers made of an organic material, and a recess may be formed in the organic material layer on one side. By forming multiple layers, it is possible to select each material by dividing the function, such as selecting a material having an appropriate wettability with the solder for the material of the recess that comes into contact with the solder.
  • FIG. 8 is a cross-sectional view schematically showing an example of a substrate.
  • the substrate 600 includes a base layer 601 and a recessed layer 602.
  • the base layer 601 is a layer that supports the recess layer 602, and the recess layer 602 is a layer on which the recess 62 is formed by processing.
  • a resin material having excellent heat resistance and dimensional stability can be used for the base layer 601, and a material having excellent workability of the recess 62 can be selected for the recess layer 602.
  • a thermoplastic resin such as polyethylene terephthalate or polyimide can be used for the base layer 601 and a thermosetting resin capable of forming the recess 62 by an imprint mold can be used for the recess layer 602.
  • a substrate 600 (including the recess 62) having excellent flatness can be obtained by sandwiching a thermosetting resin between polyethylene terephthalate and an imprint mold and heating and pressurizing the resin.
  • a material having high light transmittance may be used for the base layer 601.
  • the material having high light transparency may be, for example, polyethylene terephthalate, transparent (colorless type) polyimide, polyamide or the like.
  • the recess 62 is formed using a photocurable material
  • a photocurable material for example, an appropriate amount of the photocurable material is applied to the surface of the imprint mold, a polyethylene terephthalate film is placed on the surface, and the recess 62 is added by a roller from the polyethylene terephthalate side. Irradiate ultraviolet light while pressing. Then, after the photocurable material is cured, the imprint mold is peeled off to obtain a substrate 600 having a layer of polyethylene terephthalate and a layer of the photocurable material, and the recess 62 formed of the photocurable material. be able to.
  • the material composition of the inner wall and the bottom of the recess 62 can be changed.
  • the inner wall and the bottom of the recess 62 may be made of the same resin material. Further, the inner wall and the bottom of the recess 62 may be made of different resin materials (for example, a thermosetting material and a thermoplastic material).
  • a photosensitive material may be used as the organic material.
  • the photosensitive material may be a positive type photosensitive material or a negative type photosensitive material.
  • the recess 62 can be easily formed by forming a photosensitive material having a uniform thickness on the surface of a thermoplastic polyethylene terephthalate film and performing exposure and development.
  • the method using exposure and development is widely used in the manufacture of semiconductors, wiring boards, etc., and is a highly versatile method.
  • a direct drawing method such as a direct laser exposure.
  • the material of the base layer 601 thicker than the thickness of the material forming the concave layer 602
  • the physical characteristics of the entire substrate 600 can be dominated by the characteristics of the material of the base layer 601.
  • the material of the base layer 601 can compensate for the weakness.
  • a material that is hard to heat-shrink is selected as the material of the base layer 601 and the thickness of the base layer 601 is set to be larger than the thickness of the material forming the concave layer 602.
  • a combination of a resin material having excellent heat resistance or dimensional stability and a material in which components are less likely to elute at the melting temperature of solder fine particles, and a resin material having excellent heat resistance or dimensional stability and wettability with solder can be obtained.
  • An organic material can be appropriately selected according to the purpose, such as a combination with an appropriate material.
  • the substrate may be a substrate 600 composed of a base layer 601 and a recessed layer 602.
  • the recess layer 602 as a photosensitive material, the recess 62 can be produced by photolithography.
  • the recess layer 602 By using a light or thermosetting material, a thermoplastic material, or the like for the recess layer 602, the recess 62 can be easily produced by the imprint method. Further, since the characteristics of the entire substrate can be adjusted by changing the thickness of the base layer 601, there is an advantage that a substrate having desired characteristics can be produced.
  • the substrate 60 may be made of an inorganic material.
  • silicon silicon wafer
  • stainless steel aluminum and the like can be used as the inorganic material.
  • contamination countermeasures are easy, and they can contribute to high yield and stable production.
  • solder particles formed in the recess 62 are transferred to an electrode on a silicon wafer, if the substrate 60 is made of a silicon wafer, a material having a similar CTE or the same material will be used. As a result, misalignment, warpage, etc.
  • a method for forming the recess 62 processing by laser, cutting or the like, dry etching or wet etching method, electron beam drawing (for example, FIB processing) or the like can be used. Dry etching is widely used in the production of semiconductors, MEMS, etc., and can process inorganic materials with high accuracy on the order of microns to nano.
  • the substrate 60 glass, quartz, sapphire or the like can be used. Since these materials are transparent, they can be easily aligned when the solder particles in the recess 62 are transferred to another substrate on which the electrodes are formed.
  • processing by laser, cutting or the like dry etching or wet etching method, electron beam drawing (for example, FIB processing) or the like can be used.
  • the advantage of using an inorganic material is that it is superior in dimensional stability compared to an organic material.
  • the solder particles in the recess 62 are transferred onto the electrode, they can be transferred with high positional 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 any of the electrodes.
  • the substrate may be composed of a plurality of materials. Further, the substrate may have a plurality of layers, and the plurality of layers may be made of different materials.
  • 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 can achieve both dimensional stability and workability of the recess 62.
  • Examples of the substrate having a combination of an inorganic material and an organic material include a substrate having a base layer 601 made of a metal such as silicon, various ceramics, glass, and stainless steel, which is an inorganic material, and a concave layer 602 made of an organic material. Can be mentioned.
  • a substrate can be obtained, for example, by forming a photosensitive material on the surface of a silicon wafer and forming recesses by exposure and development.
  • the inner wall and bottom of the recess 62 may be made of a photosensitive material, or the inner wall of the recess 62 may be made of a photosensitive material and the bottom may be made of a silicon wafer.
  • the configuration of the recess 62 can be appropriately selected according to the purpose such as wettability with the solder particles in the recess 62 and ease of transfer to the electrode.
  • a photosensitive material layer is further provided on the surface of the silicon wafer by forming a photosensitive material on the surface of the silicon wafer and curing it, and the surface of the layer is provided with a layer of the photosensitive material.
  • a method of providing the recess 62 by forming a photosensitive material again and performing exposure and development can be used.
  • the photosensitive material on the surface side of the silicon wafer and the photosensitive material provided on the outermost layer may have different compositions.
  • the photosensitive material can be appropriately selected in consideration of the wettability and stainability of the solder particles.
  • the surface of the photosensitive material layer on the outermost layer may come into contact with the electrode or the surface of the substrate having the electrode. Therefore, a photosensitive material that does not damage the electrode and the substrate or does not contaminate the electrode and the substrate can be appropriately selected.
  • the photosensitive material may be a material that prevents elution of uncured components and contamination by halogen-based materials, silicone-based materials, and the like. Further, the photosensitive material may be a material having high resistance to a reducing atmosphere, flux, etc. when transferring solder particles to an electrode.
  • the photosensitive material may be a material that is resistant to a reducing atmosphere such as formic acid, hydrogen, and hydrogen radicals.
  • the photosensitive material may be a material having high resistance to the temperature at which the solder particles are transferred to the electrode.
  • the photosensitive material may be a material that is resistant to temperatures 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.
  • tin-silver-copper solder eg SAC305 (melting point 219 ° C)
  • SAC305 melting point 219 ° C
  • a material having heat resistance can be used.
  • tin-bismuth solder eg SnBi58 (melting point 139 ° C.)
  • a material having a heat resistance of 140 ° C. or higher can be used, and a material having a heat resistance of 160 ° C. or higher can be used industrially. Wider usage likelihood.
  • indium solder melting point 159 ° C.
  • a material having a heat resistance of 170 ° C. or higher can be used.
  • indium-tin solder eg, melting point 120 ° C.
  • a material having a heat resistance of 130 ° C. or higher can be used.
  • Examples of the other substrate include a substrate having a recess 62 formed of a thermosetting or thermoplastic resin on a stainless steel plate.
  • the substrate can be obtained by sandwiching a thermosetting material (resin) between a stainless steel plate and an imprint mold, heating under pressure, and then peeling off the imprint mold.
  • Examples of the other substrate include a substrate having a recess 62 formed of a photocurable material on a glass plate.
  • the substrate can be obtained by applying a photocurable material on a glass plate and exposing the substrate while pressing the imprint mold to cure the photocurable material and peeling off the imprint mold.
  • the material composition of the inner wall and the bottom of the recess 62 can be changed depending on the pressurizing condition.
  • the inner wall and the bottom of the recess 62 can be made of the same resin material.
  • the inner wall of the recess 62 can be made of a resin material and the bottom can be made of an inorganic material.
  • a composite material containing glass fiber, a filler, etc. and a resin component can also be used.
  • the composite material include a copper-clad laminate for a wiring board and the like.
  • a photosensitive material, a thermosetting resin, a photocurable resin, or the like can be applied to the surface of the copper-clad laminate to form the recess 62 as described above.
  • the copper-clad laminate mainly contains a large amount of resin material, the CTE can be lowered by combining with glass fiber, various fillers, and the like, so that the above-mentioned dimensional stability can be ensured.
  • the recess 62 is also formed on the same copper-clad laminate so that the CTEs of both become the same or close to each other, and the position at the time of transferring the solder particles in the recess 62 is obtained. It has the advantage of being easy to align and less likely to cause misalignment.
  • a packaging encapsulant can also be used as the material for the recess layer 602.
  • the sealing material any solid, liquid or film form can be used.
  • the recess 62 can be formed by laminating a sealing material on a glass, silicon wafer, or the like in a thin layer and pressurizing and heating with an imprint mold.
  • the method for manufacturing the solder bump forming member 10 includes a preparatory step of preparing a substrate having a plurality of recesses and solder fine particles, a storage step of storing at least a part of the solder fine particles in the recesses, and a solder fine particles housed in the recesses.
  • a fusion step of forming solder particles in the recesses by fusing the solder particles and an injection step of arranging (injecting) a fluidizing agent (fluid phase) in the recesses in which the solder particles are formed are provided.
  • FIG. 3A is a plan view schematically showing an example of the substrate 60
  • FIG. 3B is a cross-sectional view taken along the line Ib-Ib of FIG. 3A.
  • the substrate 60 shown in FIG. 3A has a plurality of recesses 62.
  • the plurality of recesses 62 may be regularly arranged in a predetermined pattern.
  • the positions and numbers of the plurality of recesses 62 may be set according to the shape, size, pattern, etc. of the electrodes to be connected.
  • the distance L between adjacent recesses is not particularly limited, but can be 0.1 times or more the average particle size of the contained solder particles, and may be 1 time or more.
  • the distance L can be appropriately adjusted by arranging the electrodes forming the solder bumps.
  • the distance between the recesses is not the distance between the centers of the recesses, but the distance from the edge of the recess opening to the edge.
  • the recess 62 of the base 60 is preferably formed in a tapered shape in which the opening area expands from the bottom 62a side of the recess 62 toward the surface 60a side of the base 60. That is, as shown in FIGS. 3A and 3B, the width of the bottom 62a of the recess 62 (the width a in FIGS. 3A and 3B) is the opening at the surface 60a of the recess 62. Is preferably narrower than the width of (width b in FIGS. 3 (a) and 3 (b)).
  • the size of the recess 62 may be set according to the size of the target solder particles.
  • the shape of the recess 62 may be a shape other than the shapes shown in FIGS. 3 (a) and 3 (b).
  • the shape of the opening on the surface 60a of the recess 62 may be an ellipse, a triangle, a quadrangle, a polygon, or the like, in addition to the circular shape as shown in FIG. 3A.
  • the shape of the recess 62 in the cross section perpendicular to the surface 60a may be, for example, the shape shown in FIG. 4 (a) to 4 (h) are cross-sectional views schematically showing an example of the cross-sectional shape of the concave portion of the substrate.
  • the width (width b) of the opening on the surface 60a of the recess 62 is the maximum width in the cross-sectional shape.
  • 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 electrodes, the solder particles 1 can easily come out from the recess 62, and the transfer rate is improved. Can be expected. Further, by appropriately adjusting the width (width b) of the opening, the position shift when the solder particles 1 are transferred onto the electrodes is less likely to occur, and the solder bumps are easily formed at the correct positions.
  • the solder fine particles prepared in the preparatory step may contain fine particles having a particle size smaller than the width (width b) of the opening on the surface 60a of the recess 62, and may contain more fine particles having a particle size smaller than the width b. Is preferable.
  • the D10 particle size of the particle size distribution is preferably smaller than the width b
  • the D30 particle size of the particle size distribution is more preferably smaller than the width b
  • the D50 particle size of the particle size distribution is smaller than the width b. More preferred.
  • the particle size distribution of the solder fine particles can be measured using various methods according to the size. For example, a dynamic light scattering method, a laser diffraction method, a centrifugal sedimentation method, an electrical detection band method, a resonance type mass measurement method, or the like can be used. Further, a method of measuring the particle size from an image obtained by an optical microscope, an electron microscope, or the like can be used. Specific devices include a flow-type particle image analyzer, a microtrack, a Coulter counter, and the like.
  • the value is not particularly limited, but from the viewpoint of improving the filling property into the recess 62 by the combination of large and small fine particles, C.I. V.
  • the value is preferably high.
  • C.I. V. The value may exceed 20%, preferably 25% or more, more preferably 30% or more.
  • V. The value is calculated by dividing the standard deviation of the particle size measured by the above method by the average particle size (D50 particle size) and multiplying by 100.
  • the solder fine particles may contain tin or a tin alloy.
  • tin alloy for example, In—Sn alloy, In—Sn—Ag alloy, Sn—Au alloy, Sn—Bi alloy, Sn—Bi—Ag alloy, Sn—Ag—Cu alloy, Sn—Cu alloy and the like are used. be able to. Specific examples of these tin alloys include the following examples.
  • the solder fine particles may contain indium or an indium alloy.
  • the indium alloy for example, an In—Bi alloy, an In—Ag alloy, or the like can be used. Specific examples of these indium alloys include the following examples. -In-Bi (In66.3% by mass, Bi33.7% by mass, melting point 72 ° C.) -In-Bi (In33.0% by mass, Bi67.0% by mass, melting point 109 ° C) -In-Ag (In97.0% by mass, Ag3.0% by mass, melting point 145 ° C)
  • the above tin alloy or indium alloy can be selected according to the application (temperature at the time of use) of the solder particles.
  • an In—Sn alloy or a Sn—Bi alloy may be adopted.
  • solder particles that can be fused at 150 ° C. or lower can be obtained.
  • a material having a high melting point such as Sn—Ag—Cu alloy or Sn—Cu alloy is used, solder particles capable of maintaining high reliability even after being left at a high temperature can be obtained.
  • the solder fine particles may contain one or more selected from Ag, Cu, Ni, Bi, Zn, Pd, Pb, Au, P and B.
  • Ag or Cu may be contained from the following viewpoints. That is, when the solder fine particles contain Ag or Cu, the melting point of the obtained solder particles can be lowered to about 220 ° C., and the solder particles having excellent bonding strength with the electrode can be obtained, so that better conduction reliability can be obtained. The effect of obtaining sex is achieved.
  • the Cu content of the solder fine particles is, for example, 0.05 to 10% by mass, and may be 0.1 to 5% by mass or 0.2 to 3% by mass.
  • the Cu content is 0.05% by mass or more, it becomes easy to obtain solder particles capable of achieving good solder connection reliability. Further, when the Cu content is 10% by mass or less, solder particles having a low melting point and excellent wettability can be easily obtained, and as a result, the connection reliability of the electrode with solder bumps tends to be improved.
  • the Ag content of the solder fine particles is, for example, 0.05 to 10% by mass, and may be 0.1 to 5% by mass or 0.2 to 3% by mass.
  • the Ag content is 0.05% by mass or more, it becomes easy to obtain solder particles capable of achieving good solder connection reliability.
  • the Ag oil content is 10% by mass or less, solder particles having a low melting point and excellent wettability can be easily obtained, and as a result, the connection reliability of the electrode with solder bumps tends to be improved.
  • the solder fine particles prepared in the preparatory step are accommodated in each of the recesses 62 of the substrate 60.
  • the accommodating step may be a step of accommodating all the solder fine particles prepared in the preparatory step into the recess 62, and a part of the solder fine particles prepared in the preparatory step (for example, the width b of the opening of the recess 62 among the solder fine particles). It may be a step of accommodating a smaller particle) in the recess 62.
  • FIG. 5 is a cross-sectional view schematically showing a state in which the solder fine particles 111 are housed in the recess 62 of the substrate 60. As shown in FIG. 5, a plurality of solder fine particles 111 are housed in each of the plurality of recesses 62.
  • the amount of the solder fine particles 111 contained in the recess 62 is, for example, preferably 20% or more, more preferably 30% or more, still more preferably 50% or more, based on the volume of the recess 62. , 60% or more is most preferable. As a result, the variation in the accommodating amount is suppressed, and it becomes easy to obtain solder particles having a smaller particle size distribution.
  • the method of accommodating the solder fine particles in the recess 62 is not particularly limited.
  • the accommodating method may be either dry or wet.
  • the solder fine particles prepared in the preparation step are placed on the substrate 60, and the surface 60a of the substrate 60 is rubbed with a squeegee to remove the excess solder fine particles while accommodating sufficient solder fine particles in the recess 62. can do.
  • the width b of the opening of the recess 62 is larger than the depth of the recess 62, solder fine particles may pop out from the opening of the recess 62.
  • a squeegee is used, the solder fine particles protruding from the opening of the recess 62 are removed.
  • Examples of the method of removing the excess solder fine particles include a method of blowing compressed air, a method of rubbing the surface 60a of the substrate 60 with a non-woven fabric or a bundle of fibers, and the like. Since these methods have a weaker physical force than the squeegee, they are preferable for handling easily deformable solder fine particles. Further, in these methods, the solder fine particles protruding from the opening of the recess 62 can be left in the recess.
  • the fusion step is a step of fusing the solder fine particles 111 contained in the recess 62 (for example, by heating to 130 to 260 ° C.) to form the solder particles 1 inside the recess 62.
  • the solder fine particles 111 housed in the recess 62 are united by melting and spheroidized by surface tension.
  • the molten solder follows the bottom portion 62a to form the flat surface portion 11.
  • the formed solder particles 1 have a shape having a flat surface portion 11 on a part of the surface. In this way, the solder bump forming member 10 shown in FIG. 1 is obtained.
  • Examples of the method of melting the solder fine particles 111 contained in the recess 62 include a method of heating the solder fine particles 111 to a temperature equal to or higher than the melting point of the solder. Due to the influence of the oxide film, the solder fine particles 111 may not melt or spread even when heated at a temperature equal to or higher than the melting point, and may not be united. Therefore, the solder fine particles 111 are exposed to a reducing atmosphere to remove the surface oxide film of the solder fine particles 111, and then heated to a temperature equal to or higher than the melting point of the solder fine particles 111 to melt the solder fine particles 111 and spread them wet. It can be unified.
  • the solder fine particles 111 are melted in a reducing atmosphere.
  • the method for manufacturing the solder bump forming member may further include a reduction step of exposing the solder fine particles contained in the recesses to the reducing atmosphere before the fusion step. Further, in the fusion step of the method for manufacturing the solder bump forming member, the solder fine particles may be fused in a reducing atmosphere.
  • the method for creating a reducing atmosphere is not particularly limited as long as the above effects can be obtained, and for example, there is a method using hydrogen gas, hydrogen radical, formic acid gas, or the like.
  • a hydrogen reduction furnace, a hydrogen radical reduction furnace, a formic acid reduction furnace, or a conveyor furnace or a continuous furnace thereof the solder fine particles 111 can be melted in a reducing atmosphere.
  • These devices may be equipped with a heating device, a chamber filled with an inert gas (nitrogen, argon, etc.), a mechanism for evacuating the inside of the chamber, etc., which makes it easier to control the reducing gas. Become. Further, if the inside of the chamber can be evacuated, the voids can be removed by reducing the pressure after the solder fine particles 111 are melted and united, and the solder particles 1 having further excellent connection stability can be obtained.
  • Profiles such as reduction, melting conditions, temperature, and atmosphere adjustment in the furnace of the solder fine particles 111 may be appropriately set in consideration of the melting point, particle size, recess size, material of the substrate 60, and the like of the solder fine particles 111.
  • the substrate 60 in which the solder fine particles 111 are filled in the recesses is inserted into the furnace, vacuumed, and then the reducing gas is introduced to fill the inside of the furnace with the reducing gas, and the surface oxide film of the solder fine particles 111 is formed.
  • the reducing gas is removed by vacuuming, and then the gas is heated to a temperature equal to or higher than the melting point of the solder fine particles 111 to dissolve and coalesce the solder fine particles to form the solder particles in the recess 62. After filling with nitrogen gas, the temperature inside the furnace is returned to room temperature to obtain solder particles 1. Further, for example, the substrate 60 in which the solder fine particles 111 are filled in the recesses is inserted into the furnace, and after vacuuming, the reducing gas is introduced to fill the inside of the furnace with the reducing gas, and the in-core heater is used.
  • the solder fine particles 111 are heated to remove the surface oxide film of the solder fine particles 111, then the reducing gas is removed by vacuuming, and then the solder fine particles 111 are heated to the melting point or higher to dissolve and coalesce the solder fine particles. After forming the solder particles in the recess 62, the temperature inside the furnace is returned to room temperature after filling with nitrogen gas to obtain the solder particles 1.
  • the substrate 60 in which the solder fine particles 111 are filled in the recesses is inserted into the furnace, and after vacuuming, the reducing gas is introduced to fill the inside of the furnace with the reducing gas, and the in-core heater is used.
  • the reducing gas is introduced to fill the inside of the furnace with the reducing gas, and the in-core heater is used.
  • the surface oxide film of the solder fine particles 111 is removed by reduction, and at the same time, the solder fine particles are melted and united to form solder particles in the recess 62, which is reduced by vacuuming.
  • the temperature in the furnace is returned to room temperature after filling with nitrogen gas, and the solder particles 1 can be obtained. In this case, since the temperature rise and fall in the furnace need only be adjusted once, there is an advantage that the processing can be performed in a short time.
  • the inside of the furnace may be made into a reducing atmosphere again to add a step of removing the surface oxide film that could not be completely removed. As a result, it is possible to reduce residues such as solder fine particles remaining unfused and a part of the oxide film remaining unfused.
  • the substrate 60 in which the solder fine particles 111 are filled in the recesses is placed on the conveyor and passed through a plurality of zones in succession to obtain the solder particles 1.
  • the substrate 60 in which the solder fine particles 111 are filled in the recesses is placed on a conveyor set at a constant speed and passed through a zone filled with an inert gas such as nitrogen or argon at a temperature lower than the melting point of the solder fine particles 111.
  • the surface oxide film of the solder fine particles 111 is removed by 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, and then nitrogen or nitrogen having a temperature equal to or higher than the melting point of the solder fine particles 111 is removed.
  • the solder fine particles 111 are melted and coalesced by passing through a zone filled with an inert gas such as argon, and then passed through a cooling zone filled with an inert gas such as nitrogen or argon to obtain solder particles 1. be able to.
  • the substrate 60 in which the solder fine particles 111 are filled in the recesses is placed on a conveyor set at a constant speed and passed 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 the solder fine particles 111. Subsequently, the surface oxide film of the solder fine particles 111 is removed, melted and coalesced by passing through a zone in which a reducing gas such as formic acid gas having a temperature equal to or higher than the melting point of the solder fine particles 111 exists, and then nitrogen or argon or the like is used.
  • the solder particles 1 can be obtained by passing through a cooling zone filled with the inert gas.
  • a film-like material can be continuously processed by roll-to-roll.
  • a continuous roll product of the substrate 60 in which the solder fine particles 111 are filled in the recesses is produced, a roll unwinder is installed on the inlet side of the conveyor furnace, and a roll winder is installed on the outlet side of the conveyor furnace to maintain a constant speed.
  • the solder fine particles 111 filled in the recesses can be fused.
  • the solder particles 1 having a uniform size can be formed regardless of the material and shape of the solder fine particles 111.
  • indium-based solder can be precipitated by plating, but it is difficult to precipitate it in the form of particles, and it is soft and difficult to handle.
  • indium-based solder particles having a uniform particle size can be easily produced.
  • the formed solder particles 1 can be handled in a state of being housed in the recess 62 of the substrate 60, the solder particles 1 can be transported and stored without being deformed.
  • solder particles 1 are housed in the recesses 62 of the substrate 60, the solder particles can be brought into contact with the electrodes without being deformed.
  • the average particle size of the obtained solder particles may be 1 to 35 ⁇ m, and C.I. V. The value may be 20% or less.
  • solder fine particles 111 may have a large variation in particle size distribution or a distorted shape, and can be suitably used as a raw material if they can be accommodated in the recess 62.
  • the shape of the recess 62 of the substrate 60 can be freely designed 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 recess 62, the size of the solder particles 1 can be freely designed by designing the recess 62.
  • the fluidizing agent is arranged in the recess 62 in which the solder particles 1 are formed.
  • the method of arranging the fluidizing agent is not particularly limited, but for example, a method of immersing the substrate 60 in a liquid fluidizing agent solution and pulling it up, or applying the liquid fluidizing agent on the substrate 60 (particularly on the recess 62). , Dropping and the like. Further, in the case of a solid fluidizing agent, a method of arranging a fluidizing agent having a diameter smaller than the diameter of the recess 62 on the surface of the substrate 60 and filling the recess 62 with a squeegee can be mentioned.
  • a method of arranging the fluidizing agent by CVD, vapor deposition, sputtering, or the like can be mentioned.
  • the excess fluidizing agent overflowing from the recess 62 may be removed. Examples of the removing method include volatilization under reduced pressure, squeegee, wiping, scraping, laser etching, and blasting.
  • liquid fluidizing agent For example, an appropriate amount of the liquid fluidizing agent is dropped onto the substrate 60 (on the recess 62), the liquid fluidizing agent is spread in the recess 62 by the squeegee, and then filled in the recess 62.
  • the liquid fluidizing agent can be removed.
  • the fluidizing agent that cannot be completely removed by the squeegee can be wiped off with, for example, a dust-free clean cloth.
  • the method for manufacturing the solder bump forming member 10 includes a pre-step of preparing a substrate having a plurality of recesses, solder particles and a fluidizing agent, and an arrangement step of arranging the solder particles and the fluidizing agent in the recesses. You may. In this way, the solder particles 1 can be once taken out from the substrate 60, and the solder particles 1 and the fluidizing agent F can be rearranged in the recesses of the substrate again to produce a solder bump forming member. According to this method, the solder particles 1 can be separated from the solder fine particles 111 that did not become the solder particles 1 in the melting step, the solder fine particles 111 existing outside the recess 62, other residues, foreign substances, and the like.
  • the substrate 60 having the solder particles 1 in the recess 62 is immersed in the solvent, and the solder particles 1 are taken out from the recess 62.
  • the substrate 60 from which the solder particles 1 have been taken out is pulled out from the solvent, foreign matter is removed from the solvent by passing the solvent through a filter, a mesh, or the like.
  • the solder particles 1 are once dispersed in a solvent and allowed to stand to perform sedimentation separation.
  • the solder particles 1 and the residue for example, solder fine particles 111 and foreign matter
  • the mixture of the solder particles 1 and the solvent is vacuum-dried to obtain high-purity solder particles 1.
  • the solder particles 1 are rearranged in the recess 62 on the surface of the substrate 60.
  • the fluidizing agent can be arranged in the recess 62.
  • the solder particles 1 may be arranged in the recess 62 after the fluidizing agent is arranged in the recess 62 in advance.
  • the fluidizing agent and the solder particles 1 may be mixed in advance, and the mixture may be arranged in the recess 62.
  • the substrate on which the solder particles are rearranged may be the substrate used when producing the solder particles, or may be a different substrate.
  • solder particles 1 in addition to those obtained by the above method, an atomizing method, a water atomizing method, a method of cutting and dissolving fine wires, and a method of producing fine solder droplets using a precision ejection head.
  • Those prepared by a known method such as, etc. can be used.
  • the method for manufacturing an electrode substrate with solder bumps includes a preparatory step for preparing the solder bump forming member and a substrate having a plurality of electrodes, and a surface having a recess of the solder bump forming member and a surface having electrodes of the substrate. It includes an arrangement 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.
  • substrates (circuit members) having a plurality of electrodes on the surface include chip components such as IC chips (semiconductor chips), resistor chips, capacitor chips, and driver ICs; rigid type package substrates. These circuit members are provided with circuit electrodes, and are generally provided with a large number of circuit electrodes.
  • substrates having a plurality of electrodes on the surface include wiring substrates such as flexible tape substrates having metal wiring, flexible printed wiring boards, and glass substrates on which indium tin oxide (ITO) is vapor-deposited.
  • ITO indium tin oxide
  • Electrodes include copper, copper / nickel, copper / nickel / gold, copper / nickel / palladium, copper / nickel / palladium / gold, copper / nickel / gold, copper / palladium, copper / palladium / gold, and copper.
  • / Tin, copper / silver, indium tin oxide and other electrodes can be mentioned.
  • Electrodes can be formed by electroless plating or electroplating or sputtering or etching of metal foil.
  • FIG. 6A and 6 (b) are cross-sectional views schematically showing an example of a manufacturing process of an electrode substrate with solder bumps.
  • the substrate 60 shown in FIG. 6A is in a state in which one solder particle 1 and a fluidizing agent F are housed in each of the recesses 62.
  • the substrate 2 has a plurality of electrodes 3 on the surface.
  • the surface on the electrode 3 side of the substrate 2 is brought into contact with the surface of the substrate 60 on the opening side of the recess 62 so as to face each other.
  • the number of solder particles 1 that come into contact with the individual electrodes 3 is not particularly limited, and may be one particle per electrode and may be a plurality of particles per electrode.
  • the force acting between the solder particles 1 and the recess 62 (for example, an intermolecular force such as van der Waals force) is larger than the gravity applied to the solder particles 1, it is assumed that the main surface of the substrate 60 is directed downward. However, the solder particles 1 do not fall off and remain in the recess 62. Further, when at least a part of the solder particles 1 is in contact with the bottom portion and / or the inner wall portion of the recess 62 and has a flat portion, the solder particles 1 are in close contact with the recess 62 and are difficult to fall off.
  • an intermolecular force such as van der Waals force
  • the fluidizer F is heated by heating the entire electrode substrate and substrate 60 to a temperature higher than the melting point of the solder particles 1 (for example, 130 to 260 ° C.) while the solder particles and the electrodes are in contact with each other.
  • the solder particles 1 that have become easier to flow come into contact with the electrode 3 and melt to form solder bumps on the electrode 3.
  • the solder particles 1 are brought into contact with the solder bump forming member 10 and the substrate 2 in a pressurized state, and the temperature of the solder particles 1 is equal to or higher than the melting point of the solder particles. May be heated to.
  • the pressurized state is a state in which the solder bump forming member 10 and the substrate 2 are pressed against each other with a force of about 30 to 600 Pa in the directions of arrows A and B in FIG. 6A.
  • the solder particles 1 are housed in the recess 62 and are pressed against the electrodes. Therefore, even if the solder particles 1 flow due to the action of the fluidizing agent F, the solder particles 1 in the adjacent recesses 62 are unlikely to be mixed with each other, and solder bumps of the same size can be formed only on the desired electrodes. In addition, it is difficult for the solder to bridge the adjacent electrodes, and short-circuit defects can be suppressed.
  • the solder particles 1 are rapidly oxidized by heating in the atmosphere, and it is difficult for the solder particles 1 to spread wet on the electrode 3, so that the atmosphere at the time of heating is preferably a deoxidized atmosphere.
  • it may be an inert gas atmosphere such as nitrogen or argon, a vacuum atmosphere, or the like.
  • a reflow furnace (under a nitrogen atmosphere) and a vacuum reflow furnace generally used in the solder joining process can be used, and a conveyor type reflow furnace under a nitrogen atmosphere, a batch type (chamber type) reflow furnace and the like can be used.
  • a laminator can also be used. If it is a roller type laminator, pressurization and heating can be applied at the same time. Further, a vacuum pressurizing laminator can also be used. The vacuum pressurizing laminator is preferable because the inside of the chamber can be evacuated and pressurization and heating can be performed at the same time, so that the solder bumps can be easily transferred onto the electrode 3. In addition, since continuous transportation by the carrier film is possible, there is an advantage that productivity can be increased.
  • solder particles 1 may not melt or spread even when heated at a temperature higher than the melting point due to the influence of the oxide film. Therefore, 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. Further, it is preferable that the solder particles 1 are melted in a reducing atmosphere. By heating the solder particles 1 to a temperature equal to or higher than the melting point of the solder particles 1 and creating 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 to melt the solder particles 1. Wetting and spreading can proceed efficiently.
  • the method for manufacturing an electrode substrate with solder bumps further includes a reduction step of exposing the solder particles (and / or electrodes) to a reducing atmosphere before the placement step or after the placement step and before the heating step. It's okay.
  • 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.
  • the electrodes and the opening surfaces of the solder bump forming members are brought into close contact with each other (under pressure if necessary), so that the solder bumps are formed only on the electrodes and the adjacent electrodes. Bridges due to solder between them are easily suppressed.
  • the description of the manufacturing method of the solder bump forming member can be referred to as appropriate.
  • the method for manufacturing an electrode substrate with solder bumps may further include a removal step of removing the solder bump forming member from the substrate after the heating step.
  • the solder bump forming member 10 is removed from the substrate 2 (removal step) to obtain the electrode substrate 20 with solder bumps.
  • FIG. 6B is a schematic view of the electrode substrate 20 with solder bumps thus obtained.
  • the method for manufacturing the electrode substrate with solder bumps may further include a cleaning step of removing the solder particles 1 not bonded to the electrode after the removing step.
  • the cleaning method include blowing compressed air, rubbing the surface of the substrate with a non-woven fabric or a bundle of fibers, and the like.
  • an electrode substrate 20 with solder bumps having a substrate 2, an electrode 3, and a solder bump 1A in this order.
  • connection structure 7 (a) and 7 (b) are cross-sectional views schematically showing an example of a manufacturing process of the connection structure.
  • a method of manufacturing the connection structure will be described with reference to FIGS. 7 (a) and 7 (b).
  • the electrode substrate 20 with solder bumps shown in FIG. 6B is prepared in advance.
  • another substrate 4 having a plurality of other electrodes 5 on the surface is prepared.
  • both are arranged so that the solder bump 1A and the other electrode 5 face each other.
  • pressure is applied in the thickness direction of the laminated body of these members (directions of arrows A and B shown in FIG. 7A).
  • the solder bump 1A melts between the electrode 3 and the other electrodes 5. After that, by cooling the whole, a solder layer 1B is formed between the electrode 3 and the other electrodes 5, and the electrodes are electrically connected to each other.
  • an atmosphere in which oxygen is blocked For example, heating in an atmosphere of an inert gas such as nitrogen is preferable.
  • an inert gas such as nitrogen is preferable.
  • a vacuum reflow furnace, a nitrogen reflow furnace, or the like can be used.
  • solder bump 1A it is preferable to heat the solder bump 1A in a reducing atmosphere in order to melt the solder bump 1A by heating and more preferably join the opposing electrodes 3 and 5 to each other.
  • Hydrogen gas, hydrogen radicals, formic acid and the like can be used to create a reducing atmosphere.
  • 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.
  • the oxide film on the surface of the solder bump 1A and the oxide film on the surface of the electrode 5 can be reduced and removed, so that the solder bump 1A easily wets and spreads on the electrode 5, and the electrode is passed through the solder layer 1B. A more stable bond is achieved between 3 and the electrode 5.
  • the electrode substrate 20 with solder bumps shown in FIG. 6B is prepared in advance. Further, another substrate 4 having a plurality of other 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, pressure is applied in the thickness direction of the laminated body of these members (directions of arrows A and B shown in FIG. 7A). By heating the whole to a temperature higher than the melting point of the solder bump 1A (for example, 130 to 260 ° C.) when pressurizing, the solder bump 1A melts between the electrode 3 and the other electrodes 5.
  • a temperature higher than the melting point of the solder bump 1A for example, 130 to 260 ° C.
  • a solder layer 1B is formed between the electrode 3 and the other electrodes 5, and the electrodes are electrically connected to each other.
  • an atmosphere of an inert gas such as nitrogen
  • a reducing atmosphere examples include the above-mentioned hydrogen gas, hydrogen radicals, formic acid and the like.
  • 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, and the like can be used.
  • a material having a reducing action can be used as a method of creating a reducing atmosphere.
  • a flux material or a material containing a flux component can be arranged in the vicinity of the solder bump 1A, the electrode 5, and the electrode 3.
  • a paste, a film or the like containing a flux material and a material containing a flux component can be used.
  • the electrode substrate 20 with solder bumps shown in FIG. 6B is prepared in advance.
  • a flux material or a paste containing a flux component is arranged on the entire surface of the electrode substrate 20 on which the solder bumps 1A are formed, or in the vicinity of the electrode 3 including the solder bumps 1A and the solder bumps 1A.
  • solder bump 1A and the other electrode 5 face each other.
  • the solder bump 1A and the other electrode 5 are brought into contact with each other through, for example, a flux material or a paste containing a flux component, and brought to a temperature higher than the melting point of the solder bump 1A (for example, 130 ° C. to 260 ° C.). At least by heating, the solder bump 1A melts between the electrode 3 and the other electrodes 5.
  • a solder layer 1B is formed between the electrode 3 and the other electrodes 5, and the electrodes are electrically connected to each other. After that, when the flux component is washed and removed, corrosion of the solder layer 1B, the electrode 3 and the electrode 5 due to the flux residue can be suppressed.
  • the electrode substrate 20 with solder bumps shown in FIG. 6B is prepared in advance. Further, another substrate 4 having a plurality of other electrodes 5 on the surface is prepared, and a flux material or a paste containing a flux component is arranged on the entire surface of the substrate 4 having the electrodes 5 or near the surface of the electrodes 5. Then, both are arranged so that the solder bump 1A and the other electrode 5 face each other. After that, the solder bump 1A and the other electrode 5 are brought into contact with each other via, for example, a flux material and a paste containing a flux component, and brought to a temperature higher than the melting point of the solder bump 1A (for example, 130 ° C. to 260 ° C.). At least by heating, the solder bump 1A melts between the electrode 3 and the other electrodes 5. After that, by cooling the whole, a solder layer 1B is formed between the electrode 3 and the other electrodes 5, and the electrodes are electrically connected to each other.
  • the electrode substrate 20 with solder bumps shown in FIG. 6B is prepared in advance.
  • a film containing a flux component is arranged on the surface side of the electrode substrate 20 on which the solder bumps 1A are formed.
  • another substrate 4 having a plurality of other 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. After that, the solder bump 1A and the other electrode 5 are kept in contact with each other via a film containing a flux component, or a pressure is applied between the opposing electrodes 3 and 5 to contain the flux component between them.
  • the electrode 3 and other parts are heated by at least heating to 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 in contact with each other so as to push the film away.
  • the solder bump 1A melts between the electrodes 5.
  • a solder layer 1B is formed between the electrode 3 and the other electrodes 5, and the electrodes are electrically connected to each other.
  • the paste and film containing the flux component may contain a thermosetting material.
  • the thermosetting component is cured at the same time as the solder bump 1A is melted, and the electrode substrate 20 and the substrate 4 can be fixed.
  • the curing of the thermosetting material may be carried out by heating again in a subsequent step separately from the melting and heating of the solder bump 1A.
  • the film containing the flux component may be placed on the surface side of the substrate 4 on which the electrode 5 is formed in advance.
  • the selection of the placement position of the film containing the flux component on the solder bump 1A side or the substrate 4 side having the electrode 5 depends on the shape of the electrode, the shape and size of the solder bump 1A, and the joining process. It can be selected as appropriate according to convenience.
  • a heating method for melting the solder bump 1A under vacuum, for example, a method of heating a heating plate in a reflow furnace and transmitting it to the solder bump 1A via a substrate 2 and a substrate 4 in contact with the heating plate, infrared rays. There is a method using radiation such as. Further, in addition to or in combination with the above-mentioned heating method using a heating plate and infrared rays, a method of heating the solder bump 1A via the heated gas and gas can be used. Specifically, the solder bump 1A can be heated by heating the inert gas, nitrogen, hydrogen, hydrogen radicals, and formic acid.
  • the flux material and the flux component may include at least one selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, benzoic acid, and malic acid.
  • a method of using electromagnetic waves such as microwaves.
  • a specific electromagnetic wave that heats the components of the electrode 3, the electrode 5, and the solder bump 1A can be applied from the outside.
  • the substrate 4 and the substrate 2 are resin substrates
  • the electromagnetic wave is transmitted through the substrate 4 and the substrate 2, and the electrode 3 and the solder bump 1A or the electrode 5 are formed. It is heated by electromagnetic waves.
  • the portion to be joined can be selectively heated, there is an advantage that an extra heat history is not left.
  • the solder bump 1A can be melted and the electrode 3 and the electrode 5 can be reliably joined. Further, since the heat history is unlikely to remain in the entire system to be joined, there is an advantage that warpage and decomposition after joining can be easily suppressed. Further, when microwaves are used, the solder bump 1A can be melted in a shorter time than using a heating plate, infrared rays, heating gas, etc. as described above, so that the heat history to the entire system to be joined is reduced. There is an advantage that the above-mentioned effect can be easily obtained.
  • the solder bump 1A and the electrode 5 to be joined or melted can be locally heated. Therefore, it is not necessary to heat the entire system, and even if there are materials with low heat resistance, other electronic components, etc. that do not want to be heated in the vicinity of the electrodes 3 and 5, the solder bumps 1A are melted and joined. be able to.
  • Another method is to use ultrasonic waves. For example, when an ultrasonic vibrator is arranged on the side opposite to the electrode 3 of the substrate 2 and ultrasonic waves are applied, the solder bump 1A is melted by the vibration energy of the ultrasonic waves. As a result, the electrode 3 and the electrode 5 previously arranged at the opposite positions of the electrode 3 are joined via the solder layer 1B. Since the solder bump 1A can be melted in a short time in the bonding by ultrasonic waves, it is not necessary to apply heat to the entire substrate 2 and the substrate 4, and even if the substrate 2 and the substrate 4 are made of a material having low heat resistance, the electrodes are surely electrode. 3 and the electrode 5 can be joined.
  • FIG. 7B is a schematic view of the connection structure 30 obtained in this way. That is, FIG. 7B schematically shows a state in which the electrode 3 of the substrate 2 and the other electrode 5 of the other substrate 4 are connected via a solder layer 1B formed by fusion. It is shown.
  • the term "fused” means that at least a part of the electrode is joined by a solder (solder bump 1A) melted by heat, and then the solder is joined to the surface of the electrode through a step of solidifying the solder. Means the state.
  • the connection structure 30 includes a first circuit member having a plurality of electrodes on the substrate and its surface, a second circuit member having a plurality of other electrodes on the other substrate and its surface, and a plurality of electrodes and a plurality of electrodes. It can be said that a solder layer is provided between the other electrodes.
  • the space between the first circuit member and the second circuit member can be filled with, for example, an underfill material containing an epoxy resin as a main agent.
  • connection structures such as semiconductor memory and semiconductor logic chips, connection parts for primary and secondary mounting of semiconductor packages, and junctions such as CMOS image elements, laser elements, and LED light emitting elements.
  • Examples include devices such as cameras, sensors, liquid crystal displays, personal computers, mobile phones, smartphones, and tablets used.
  • Step a1 Classification of solder fine particles 100 g of Sn-Bi solder fine particles (manufactured by 5N Plus, melting point 139 ° C., Type 8) are immersed in distilled water, ultrasonically dispersed, then allowed to stand, and the solder fine particles float in the supernatant. Was recovered. This operation was repeated to recover 10 g of solder fine particles. The average particle size of the obtained solder fine particles was 1.0 ⁇ m, and C.I. V. The value was 42%.
  • Step b1 Arrangement on the substrate
  • the opening diameter is 2.3 ⁇ m ⁇
  • the bottom diameter is 2.0 ⁇ m ⁇
  • the depth is 2.0 ⁇ m (the bottom diameter of 2.0 ⁇ m ⁇ is 2.3 ⁇ m ⁇ when the opening is viewed from the top surface, as shown in Table 1.
  • a substrate polyimide film, thickness 100 ⁇ m
  • the plurality of recesses were regularly arranged at intervals of 1.0 ⁇ m.
  • the solder fine particles average particle diameter 1.0 ⁇ m, CV value 42%) obtained in step a were placed in the recesses of the substrate.
  • Step c1 Formation of solder particles
  • the substrate in which the solder fine particles are arranged in the recesses in step b1 is placed in a hydrogen reduction furnace (Vacuum soldering device manufactured by Shinko Seiki Co., Ltd.), evacuated, and then hydrogen gas is put into the furnace. It was introduced and the inside of the furnace was filled with hydrogen. Then, after keeping the inside of the furnace at 280 ° C. for 20 minutes, the inside of the furnace was evacuated again, nitrogen was introduced to return the pressure to atmospheric pressure, and then the temperature inside the furnace was lowered to room temperature to form solder particles inside the recesses. ..
  • a hydrogen reduction furnace Vauum soldering device manufactured by Shinko Seiki Co., Ltd.
  • Step d1 Arrangement of flux 20 parts by mass of adipic acid as a flux component was added to 90 parts by mass of dihydroterpineol and mixed to prepare a fluid phase. This flowing phase was placed in the recess in which the solder particles obtained in step c1 were placed. Then, the surface side on which the concave portion of the substrate was formed was rubbed with a rubber squeegee to remove an excess fluid phase (flux component) that was not filled in the concave portion. Then, the surface of the base material was further wiped with a dust-free clean cloth to prepare a film for forming solder bumps.
  • Step c2 Formation of solder particles
  • the substrate in which the solder fine particles were arranged in the recesses in step b1 was put into a hydrogen radical reduction furnace (Plasma reflow device manufactured by Shinko Seiki Co., Ltd.), evacuated, and then hydrogen gas was introduced into the furnace.
  • the inside of the furnace was filled with hydrogen gas.
  • the inside of the furnace was adjusted to 120 ° C. and irradiated with hydrogen radicals for 5 minutes.
  • the hydrogen gas in the furnace is removed by vacuuming, and after heating to 170 ° C., nitrogen is introduced into the furnace to return it to atmospheric pressure, and then the temperature inside the furnace is lowered to room temperature to remove the solder particles. Formed.
  • Step c3 Formation of solder particles
  • the substrate in which the solder fine particles were arranged in the recesses in step b1 was put into a formic acid reduction furnace, evacuated, and then formic acid gas was introduced into the furnace to fill the inside of the furnace with formic acid gas. .. Then, the inside of the furnace was adjusted to 130 ° C., and the temperature was maintained for 5 minutes. After that, formic acid gas in the furnace is removed by vacuuming, and after heating to 180 ° C., nitrogen is introduced into the furnace to return it to atmospheric pressure, and then the temperature in the furnace is lowered to room temperature to remove the solder particles. Formed.
  • Step c4 Formation of solder particles
  • the substrate in which the solder fine particles were arranged in the recesses in step b1 was put into a formic acid conveyor reflow furnace (Heller Industries, Inc., 1913MK) and adjusted to 190 ° C. while being conveyed by the conveyor.
  • the soldered nitrogen zone, nitrogen and formic acid gas mixing zone, and nitrogen zone were passed continuously.
  • the nitrogen and formic acid gas mixing zone was passed in 20 minutes to form solder particles in the recesses.
  • Step e1 Preparation of evaluation chip Seven types of chips with gold bumps (3.0 ⁇ 3.0 mm, thickness: 0.5 mm) shown below were prepared.
  • Chip C1 ... Area 100 ⁇ m ⁇ 100 ⁇ m, space 40 ⁇ m, height: 10 ⁇ m, number of bumps 362 Chip C2: Area 75 ⁇ m ⁇ 75 ⁇ m, space 20 ⁇ m, height: 10 ⁇ m, number of bumps 362 Chip C3: Area 40 ⁇ m ⁇ 40 ⁇ m, space 16 ⁇ m, height: 7 ⁇ m, number of bumps 362 Chip C4: Area 20 ⁇ m ⁇ 20 ⁇ m, space 7 ⁇ m, height: 5 ⁇ m, number of bumps 362 Chip C5: Area 10 ⁇ m ⁇ 10 ⁇ m, space 6 ⁇ m, height: 3 ⁇ m, number of bumps 362 Chip C6: Area 10 ⁇ m ⁇ 10 ⁇ m, space 4 ⁇ m, height
  • Step f1 Solder bump formation (no formic acid gas used) Using the solder bump forming film (Production Example 7) produced in step c2 according to the procedures i) to iii) shown below, a chip with gold bumps (3.0 ⁇ 3.0 mm, thickness: 0.5 mm). ) was formed with solder bumps.
  • a glass plate having a thickness of 0.3 mm was placed on the hot plate, and the evaluation chip was placed on the glass plate with the gold bump facing up.
  • the solder bump forming film was arranged so that the gold bump surface of the evaluation chip and the solder bump forming film were in contact with each other so that the opening surface side of the recess of the solder bump forming film was directed downward.
  • a glass plate having a thickness of 0.3 mm was placed on the solder bump forming film, and a stainless steel weight was placed on the glass plate to bring the solder bump forming film into close contact with the gold bump.
  • a bell-shaped glass cover that allows nitrogen gas to be blown inside was prepared. With this glass cover, a sample in which a film for forming a solder bump was laminated on the evaluation chip prepared in ii) was covered. Next, nitrogen gas was introduced into the glass cover and the entire sample was placed in a nitrogen atmosphere. The hot plate of the hot plate was heated to 160 ° C. and heated for 5 minutes. Then, after returning the hot plate to room temperature, nitrogen gas was stopped and the hot plate was opened to the atmosphere.
  • the top weight, glass plate, and solder bump forming film were removed in this order. Subsequently, the evaluation chip was immersed in a methanol solution, the fluidized bed was washed and removed, and vacuum dried (40 ° C. for 60 minutes) to obtain an evaluation chip with solder bumps.
  • the evaluation chip obtained in step f1 was fixed to the surface of the pedestal for SEM observation, and the surface was subjected to platinum sputtering.
  • the number of solder bumps placed on the gold bumps was counted by SEM, and the average number of solder bumps placed on one gold bump was calculated.
  • the results are shown in Table 3.
  • the height of the solder bumps from the gold bumps was measured using a laser microscope (LEXT OLS5000-SAF manufactured by Olympus Corporation), and the average value of 100 pieces was calculated. The results are shown in Table 3.
  • solder bump formation and its evaluation were carried out by the same method as described above, except that the solder bump forming film of Production Examples 8 to 12 was used instead of the solder bump forming film of Production Example 7.
  • the evaluation results are shown in Table 3.
  • Comparative Production Example 1 A comparative solder bump forming film having solder particles in the recesses was produced in the same manner as in Production Example 8 except that step d1 (flux arrangement) was not performed. Solder bump formation and its evaluation were performed by the same method as in step f1 except that the comparative solder bump forming film was used. The results are shown in Table 3.
  • solder bumps could be formed on the gold bumps of the evaluation chips, but in Comparative Production Examples 1, no solder bumps were observed on the gold bumps of any of the evaluation chips.
  • the flux component removes the oxide film on the surface of the solder particles by heating and also cleans the surface of the gold bump (electrode). Then, the solder particles are carried to the surface of the gold bump by the flowing phase while being melted, and the solder bump can be formed on the gold bump. As shown in FIG. 1, since the fluidized phase exists in the recess, the fluidized phase removes the oxide film near the surface of the solder particles facing the gold bumps (electrodes), and the solder particles and the gold bumps are separated from each other. Contact is activated.
  • the solder particles can be in contact with the gold bump surface.
  • the flow of the solder particles and the flux in the surface direction of the solder bump forming member is suppressed, and the solder bump can be formed on the gold bump. Further, for the same reason, it is difficult for the solder particles of the adjacent recesses to join each other, and good solder bumps can be formed.
  • the concave opening surface is partially in contact with the evaluation chip side, it can be easily removed by subsequent cleaning because there is no metal (electrode) in which the solder spreads wet. Further, as shown above, since the solder particles and the flux are present in the recesses, the flow of the solder particles is suppressed in the surface direction of the solder bump forming member, and it is difficult to cause a short-circuit defect of the gold bump.
  • Step f2 Solder bump formation (using formic acid gas) Using the solder bump forming film (Production Example 7) produced in step c2 according to the procedures i) to iii) shown below, a chip with gold bumps (3.0 ⁇ 3.0 mm, thickness: 0.5 mm). ) was formed with solder bumps. i) A glass plate having a thickness of 0.3 mm was placed on a stainless steel plate having a thickness of 5 mm, and an evaluation chip was placed on the glass plate with a gold bump facing up.
  • the solder bump forming film was arranged so that the gold bump surface of the evaluation chip and the solder bump forming film were in contact with each other so that the opening surface side of the recess of the solder bump forming film was directed downward. Further, a glass plate having a thickness of 0.3 mm was placed on the solder bump forming film, and a stainless steel weight was placed on the glass plate to bring the solder bump forming film into close contact with the gold bump.
  • the stainless plate prepared in iii) was placed and flowed at a speed of 40 mm / s. In the conveyor furnace, the sample first passed through the nitrogen gas zone.
  • solder bump formation and its evaluation were performed by the same method as in step f2, except that the solder bump forming film of Production Examples 8 to 12 was used instead of the solder bump forming film of Production Example 7.
  • the evaluation results are shown in Table 4.
  • solder bumps could be formed on the gold bumps.
  • the number of solder bumps tends to increase as compared with the case where the atmosphere is not formic acid gas (Table 3). This is because the surface oxide film of the solder particles in the recess was sufficiently reduced by the flux component contained in the fluid phase and formic acid gas, and the organic matter on the surface of the gold pad was also removed by the formic acid gas. It is probable that solder bumps were easily formed on the surface. 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.
  • Comparative Production Example 1 formation of solder bumps was confirmed on the gold bumps, but the number of bumps tended to be smaller than that of Production Examples 7 to 12. Even when the same Comparative Production Example 1 was used, no solder bumps were formed when the formic acid gas atmosphere was not used, but when the formic acid gas atmosphere was used, the solder particles in some of the recesses were not formed. The surface oxide film was removed by formic acid gas, and a certain amount of solder was placed on the gold bumps. However, since the side of the recess is pressed against the gold bump, it is considered that the formic acid gas did not sufficiently remove the surface oxide film of the solder particles in the recess.
  • Step g1 Preparation of evaluation substrate Seven types of substrates with gold bumps (70 ⁇ 25 mm, thickness: 0.5 mm) shown below were prepared. The gold bumps are also formed with lead-out wiring for resistance measurement. Substrate D1 ...
  • Step h1 Joining the electrodes
  • the evaluation chip with solder bumps produced in step f1 was used to connect to the evaluation substrate with gold bumps via the solder bumps.
  • the evaluation substrate was placed on the lower hot plate of the formic acid reflow furnace (manufactured by Shinko Seiki Co., Ltd., batch type vacuum soldering device) with the gold bumps facing up.
  • the solder bump surface of the evaluation chip on which the solder bumps were formed was directed downward, and the gold bump surface of the evaluation substrate and the solder bumps were arranged so as to be in contact with each other and fixed so as not to move.
  • connection structure was prepared. The combinations of each material in the connection structure are as follows.
  • Chip C1 / Solder bump forming film / substrate D1 (2) Chip C2 / Solder bump forming film / Substrate D2 (3) Chip C3 / Solder bump forming film / Substrate D3 (4) Chip C4 / Solder bump forming film / Substrate D4 (5) Chip C5 / Solder bump forming film / Substrate D5 (6) Chip C6 / Solder bump forming film / Substrate D6 (7) Chip C7 / Solder bump forming film / Substrate D7
  • connection structure> A conduction resistance test and an insulation resistance test were performed on a part of the obtained connection structure as follows.
  • the DC resistance values were measured at the solder joints (4 points) at the chip corners where the impact was greatest, and when the measured values increased 5 times or more from the initial resistance, it was considered that breakage had occurred and evaluation was performed. A total of 80 points were measured at 4 points for each sample. The results are shown in Table 6. When the criteria of A or B below were satisfied after 20 drops, the solder connection reliability was evaluated as good. A: There were no solder connections where the initial resistance increased by 5 times or more. B: The number of solder connection portions increased by 5 times or more from the initial resistance was 1 or more and 5 or less. C: The number of solder connection portions increased by 5 times or more from the initial resistance was 6 or more and 20 or less. D: There were 21 or more solder connection parts that increased by 5 times or more from the initial resistance.
  • the initial value of the insulation resistance and the value after the migration test (standing at temperature 60 ° C., humidity 90%, 20V application for 100, 500, 1000 hours) were measured for 20 samples, and all of them were measured. of 20 samples was calculated the ratio of the sample insulation resistance is 10 9 Omega more.
  • the insulation resistance was evaluated from the obtained ratio according to the following criteria. The results are shown in Table 7. If the following criteria A or B are satisfied after 1000 hours of the migration test, it can be said that the insulation resistance is good.
  • Step i1 Preparation of evaluation substrate A liquid photosensitive resist (manufactured by Hitachi Kasei Co., Ltd., AH series) was applied to a thickness of 2.3 ⁇ m on a 6-inch silicon wafer by a spin coating method.
  • the photosensitive resist on this silicon wafer is exposed and developed to have an opening diameter of 3.1 ⁇ m ⁇ , a bottom diameter of 2.0 ⁇ m ⁇ , and a depth of 2.3 ⁇ m (the bottom diameter of 2.0 ⁇ m ⁇ is an opening diameter of 3 when the opening is viewed from the top surface.
  • An evaluation pattern having a recess located in the center of 1 ⁇ m ⁇ was formed.
  • One of the evaluation patterns has a size of 20 mm ⁇ 20 mm, and the above-mentioned recess is arranged in an area of 10 mm ⁇ 10 mm at the center thereof.
  • the positions of the recesses are arranged at positions (X-direction pitch, Y-direction pitch) relative to the electrode arrangement pattern of the evaluation chip C8, which will be described later, and three alignment marks are also arranged. This was cut out to a size of 20 mm ⁇ 20 mm by a dicer to obtain a substrate 1 for evaluation.
  • the outline of the evaluation substrate is shown in Table 8.
  • Evaluation substrates 2 to 6 were prepared with the thickness, opening diameter and pitch of the photosensitive resist as the values shown in Table 8.
  • Step j1 Preparation of solder particles
  • the solder bump forming films having the solder particles in the recesses shown in Production Examples 7 to 12 in Table 2 were obtained.
  • a stainless steel vat was filled with isopropyl alcohol, the obtained film for forming solder bumps was immersed, and ultrasonic waves of 28 kHz and 600 W were applied for 5 minutes.
  • the solder particles were separated from the recesses and dispersed in the isopropyl alcohol solvent. The solvent in which the solder particles were dispersed was allowed to stand, and the supernatant was discarded.
  • solder particles 1 to 6 having the same particle size.
  • the outline of the solder particles 1 to 6 is shown in Table 9.
  • Step k1 Arrangement of 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 dropped on the surface of the evaluation substrate 1 of 20 mm ⁇ 20 mm fixed on the glass plate, the surface of the evaluation substrate 1 was rubbed with a urethane squeegee, and the solder particles 1 and dodecane were filled in the recesses. Excess solder particles 1 and dodecane on the surface of the evaluation substrate 1 were wiped off with a clean cloth to obtain a solder bump forming film in which the solder particles 1 and dodecane were arranged in the recesses of the evaluation substrate 1.
  • Step e2 Preparation of evaluation chip
  • Chip C8 size 8 ⁇ 4 ⁇ m, pitch in X direction 16 ⁇ m, pitch in Y direction 8 ⁇ m, height: 3 ⁇ m, number of bumps 382000
  • Chip C9 Size 16 ⁇ m ⁇ 8 ⁇ m, X-direction pitch 32 ⁇ m, Y-direction pitch 16 ⁇ m, height: 5 ⁇ m, number of bumps 95700
  • Chip C10 Size 24 ⁇ m ⁇ 12 ⁇ m, X-direction pitch 48 ⁇ m, Y-direction pitch 24 ⁇ m, height: 8 ⁇ m, number of bumps 42500 Chip C11 ...
  • Step f3 Solder bump formation: Nitrogen atmosphere Using the evaluation solder bump forming film 25 produced in step k1 according to the procedures i) to iii) shown below, a chip with gold bumps (10 mm ⁇ 10 mm, thickness: Solder bumps were formed at 0.5 mm). i) The chip C8 was fixed on a glass plate of 30 mm ⁇ 30 mm (thickness 0.5 mm) with the gold bump facing up. This was adsorbed and fixed to the stage of a flip chip bonder (FC3000: manufactured by Toray Industries, Inc.).
  • FC3000 flip chip bonder
  • the evaluation substrate 1 having a size of 20 mm ⁇ 20 mm was picked up by the heating and pressurizing head, the alignment mark was read by the camera, the electrode position of the chip C8 and the recess of the evaluation substrate 1 were opposed to each other, and the evaluation substrate 1 was temporarily placed.
  • a bell-shaped glass cover that allows nitrogen gas to be blown inside was prepared. The entire hot plate was covered with this glass cover, and the temperature of the hot plate of the hot plate was raised to 150 ° C.
  • the sample prepared in ii) was placed on a hot plate, a stainless steel weight was placed on the evaluation substrate 1 on the uppermost stage, and the sample was heated in a nitrogen atmosphere for 3 minutes.
  • the chip C8 was immersed in a methanol solution, the fluidized bed was washed and removed, and vacuum dried (at 40 ° C. for 60 minutes) to obtain an evaluation chip 25 with solder bumps.
  • solder bump evaluation Formic acid gas not used>
  • the evaluation chip 25 obtained in step f1 was fixed to the surface of the SEM observation pedestal, and the surface was subjected to platinum sputtering.
  • the number of solder bumps formed on the gold bumps was counted by SEM, the solder bump formation rate was calculated, and the evaluation was performed according to the following evaluation criteria. The results are shown in Table 11. It can be said that the evaluation of the solder bump formation rate is good when the criteria of A or B are satisfied.
  • Solder bump formation rate is 90% or more
  • B Solder bump formation rate is 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%
  • solder bumps were sufficiently formed on the gold bumps. Solder bumps were formed only on the electrodes and no solder particles were present between the electrodes. Since the opening surface of the recess of the solder bump forming film is pressed against the electrode surface, there is a low possibility that the melted solder leaks from the electrode surface even if there is a fluid phase, and the solder bump can be stably formed.
  • Step f4 Solder bump formation: Formic acid atmosphere Solder bumps were formed and evaluated using the same method as in step f3, except that iii) in step f3 was replaced with the following method. The evaluation results are shown in Table 12. iii) A glass plate on which the evaluation base 1 was placed on the chip C8 was placed and fixed on a hot plate of a formic acid furnace (manufactured by Shinko Seiki Co., Ltd.), and a stainless steel weight was placed on the evaluation base 1. .. After vacuum degassing the inside of the furnace, the treatment was carried out at 150 ° C. for 3 minutes in a formic acid atmosphere, and the pressure was returned to atmospheric pressure.
  • the chip C8 was immersed in a methanol solution, the fluid phase was washed and removed, and vacuum dried (at 40 ° C. for 60 minutes) to obtain an evaluation chip 43 with solder bumps.
  • step f4 solder bumps were formed in the combinations shown in Table 12 to obtain evaluation chips 44 to 60.
  • Table 12 shows the evaluation results obtained in the same manner as above.
  • Step f5 Solder bump formation: Vacuum pressurization Solder bumps were formed and evaluated by the same method as in step f3, except that iii) in step f3 was replaced with the following method. The evaluation results are shown in Table 13. iii) A glass plate on which the evaluation substrate 1 was placed on the chip C8 was placed on a carrier film of a vacuum pressurizing laminator (MVL-500: manufactured by Japan Steel Works, Ltd.). The upper and lower heating plate temperature was set to 145 ° C., and the treatment was performed at a pressure of 0.5 MPa and a pressurization time of 3 s. Then, the evaluation substrate 1 was removed.
  • VML-500 vacuum pressurizing laminator
  • step f5 solder bumps were formed in the combinations shown in Table 13 to obtain evaluation chips 62 to 78.
  • Table 13 shows the evaluation results obtained in the same manner as above.
  • Step e3 Preparation of evaluation chip
  • Step f6 Solder bump formation: Vacuum pressurization Solder bumps were formed and evaluated by the same method as in step f3, except that iii) in step f3 was replaced with the following method. The evaluation results are shown in Table 14. iii) A glass plate on which the evaluation substrate 1 was placed on the chip C14 was placed on a carrier film of a vacuum pressurizing laminator (MVL-500: manufactured by Japan Steel Works, Ltd.). The temperature of the upper and lower hot plates was set to 150 ° C., and the treatment was performed at a pressure of 0.5 MPa and a pressurization time of 10 s. Then, the evaluation substrate 1 was removed. Subsequently, the chip C14 was immersed in a methanol solution, the fluid phase was washed and removed, and vacuum dried (at 40 ° C. for 60 minutes) to obtain an evaluation chip 79 with solder bumps.
  • VML-500 vacuum pressurizing laminator
  • step f6 solder bumps were formed in the combinations shown in Table 14 to obtain evaluation chips 80 to 96.
  • Table 14 shows the evaluation results obtained in the same manner as above.
  • Step g2 Preparation of evaluation substrate
  • Six types of substrates with gold bumps (40 ⁇ 40 mm, thickness: 0.5 mm) shown below were prepared.
  • the arrangement of the Au bumps is a position relative to the Au bumps of the chips C8 to C13, respectively, and there are three alignment marks so that the alignment can be performed.
  • the gold bumps are also formed with lead-out wiring for resistance measurement.
  • Substrate D8 Corresponding chip: Chip C8 / size 8 ⁇ 4 ⁇ m, pitch in X direction 16 ⁇ m, pitch in Y direction 8 ⁇ m, height: 3 ⁇ m, number of bumps 382000
  • Substrate D9 Preparation of evaluation substrate
  • Corresponding chip Chip C9 / size 16 ⁇ m ⁇ 8 ⁇ m, pitch in X direction 32 ⁇ m, pitch in Y direction 16 ⁇ m, height: 5 ⁇ m, number of bumps 95700 Substrate D10 ...
  • Corresponding chip Chip C10 / size 24 ⁇ m ⁇ 12 ⁇ m, pitch in X direction 48 ⁇ m, pitch in Y direction 24 ⁇ m, height: 8 ⁇ m, number of bumps 42500 Substrate D11 ...
  • Corresponding chip Chip C11 / size 72 ⁇ m ⁇ 36 ⁇ m, X-direction pitch 144 ⁇ m, Y-direction pitch 72 ⁇ m, height: 10 ⁇ m, number of bumps 4700 Substrate D12 ...
  • Corresponding chip Chip C12 / size 96 ⁇ m ⁇ 48 ⁇ m, X-direction pitch 192 ⁇ m, Y-direction pitch 96 ⁇ m, height: 13 ⁇ m, number of bumps 2600 Substrate D13 ...
  • Corresponding chip Chip C13 / size 140 ⁇ m ⁇ 70 ⁇ m, X-direction pitch 280 ⁇ m, Y-direction pitch 140 ⁇ m, height: 18 ⁇ m, number of bumps 1200
  • Step h2 Joining the electrodes
  • the evaluation chip with solder bumps produced in step f5 was used to connect the evaluation substrate with gold bumps to the evaluation substrate with solder bumps.
  • the substrate on which the gold bumps were formed was fixed to the stage of a flip chip bonder (FC3000: manufactured by Toray Industries, Inc.).
  • FC3000 manufactured by Toray Industries, Inc.
  • the evaluation chips on which the solder bumps were formed were picked up by the heating and pressurizing head and placed at positions where the gold bumps face each other from the alignment mark.
  • the substrate on which the evaluation chip was placed was placed on the lower hot plate of a formic acid reflow furnace (manufactured by Shinko Seiki Co., Ltd., batch type vacuum soldering device), and a stainless steel weight was placed on the upper part of the evaluation chip.
  • a formic acid vacuum reflow furnace manufactured by Shinko Seiki Co., Ltd., batch type vacuum soldering device
  • the formic acid vacuum reflow furnace was operated, evacuated, filled with formic acid gas, the temperature of the lower hot plate was raised to 150 ° C., and the mixture was heated for 5 minutes. Then, after discharging formic acid gas by evacuation, nitrogen substitution was performed, the lower hot plate was returned to room temperature, and the inside of the furnace was opened to the atmosphere.
  • connection structure> A part of the obtained connection structure was subjected to a conduction resistance test and an insulation resistance test in the same manner as in Step: h1. The results are shown in Tables 15, 16 and 17.
  • Step g3 Preparation of evaluation substrate Six types of substrates with copper bumps (40 ⁇ 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 so that the Cu bumps can be aligned. The Cu bumps are also formed with lead-out wiring for resistance measurement.
  • Substrate D14 Corresponding chip: Chip C14 / size 8 ⁇ 4 ⁇ m, pitch in X direction 16 ⁇ m, pitch in Y direction 8 ⁇ m, height: 3 ⁇ m, number of bumps 382000
  • Substrate D15 corresponds to Chip C14 / size 8 ⁇ 4 ⁇ m, pitch in X direction 16 ⁇ m, pitch in Y direction 8 ⁇ m, height: 3 ⁇ m, number of bumps 382000
  • Substrate D15 Substrate D15 ...
  • Corresponding chip Chip C15 / size 16 ⁇ m ⁇ 8 ⁇ m, pitch in X direction 32 ⁇ m, pitch in Y direction 16 ⁇ m, height: 5 ⁇ m, number of bumps 95700 Substrate D16 ...
  • Corresponding chip Chip C16 / size 24 ⁇ m ⁇ 12 ⁇ m, pitch in X direction 48 ⁇ m, pitch in Y direction 24 ⁇ m, height: 8 ⁇ m, number of bumps 42500 Substrate D17 ...
  • Corresponding chip Chip C17 / size 72 ⁇ m ⁇ 36 ⁇ m, X-direction pitch 144 ⁇ m, Y-direction pitch 72 ⁇ m, height: 10 ⁇ m, number of bumps 4700 Substrate D18 ...
  • Corresponding chip Chip C18 / size 96 ⁇ m ⁇ 48 ⁇ m, X-direction pitch 192 ⁇ m, Y-direction pitch 96 ⁇ m, height: 13 ⁇ m, number of bumps 2600 Substrate D19 ...
  • Corresponding chip Chip C19 / size 140 ⁇ m ⁇ 70 ⁇ m, X-direction pitch 280 ⁇ m, Y-direction pitch 140 ⁇ m, height: 18 ⁇ m, number of bumps 1200
  • Step h3 Joining the electrodes
  • the evaluation chip with solder bumps produced in step f6 was used to connect to the evaluation substrate with copper bumps via the solder bumps.
  • the evaluation substrate was set on a spin coater (SC-308S manufactured by Oshigane Co., Ltd.), and 0.5 ml of flux (WHS-003C: manufactured by Arakawa Chemical Industry Co., Ltd.) was dropped on the surface on which Cu bumps were formed.
  • a thin film flux layer was formed by treating at a rotation speed of 500 rpm for 10 s and then at 1000 rpm for 3 s.
  • the evaluation substrate was fixed to the stage of a flip chip bonder (FC3000: manufactured by Toray Industries, Inc.).
  • the evaluation chips on which the solder bumps were formed were picked up by the heating and pressurizing head and placed at positions where the bumps face each other from the alignment mark.
  • the substrate on which the evaluation chip was placed was placed on the lower heating plate of a formic acid reflow furnace (manufactured by Shinko Seiki Co., Ltd., a batch type vacuum soldering device), and a stainless steel weight was placed on the upper part of the evaluation chip.
  • the formic acid vacuum reflow furnace was operated, evacuated, filled with formic acid gas, the temperature of the lower hot plate was raised to 160 ° C., and the mixture was heated for 3 minutes. Then, after discharging formic acid gas by evacuation, nitrogen substitution was performed, the lower hot plate was returned to room temperature, and the inside of the furnace was opened to the atmosphere.
  • An appropriate amount of underfill material (CEL series manufactured by Hitachi Kasei Co., Ltd.) whose viscosity has been adjusted is placed between the evaluation chip and the evaluation substrate, filled by vacuuming, and then cured at 125 ° C. for 4 hours to form the evaluation chip and the evaluation substrate.
  • a connection structure was prepared.
  • connection structure> A part of the obtained connection structure was subjected to a conduction resistance test and an insulation resistance test in the same manner as in Step: h1. The results are shown in Tables 18, 19 and 20.

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