Surface-treated conductive particles, production method therefor, adhesive composition, and wiring-forming member

Abstract

These surface-treated conductive particles are conductive particles that have been surface-treated with a surface treatment agent containing a phosphate ester compound.

Description

Surface-treated conductive particles and their manufacturing method, as well as adhesive composition and wiring forming member.

[0001] The present invention relates to surface-treated conductive particles and a method for producing the same, as well as an adhesive composition and a component for forming wiring.

[0002] Conductive particles are used as materials for manufacturing electronic components such as semiconductor packages. For example, Patent Document 1 below proposes a wiring-forming member in which a metal foil layer is laminated on an adhesive layer containing conductive particles, as a material for easily forming a wiring layer on a printed circuit board (component-embedded substrate) that incorporates electronic components such as IC chips. With such a wiring-forming member, it is expected that a wiring layer electrically connected to the wiring can be easily formed on a substrate on which wiring has been formed.

[0003] International Publication No. 2022 / 030634 Brochure

[0004] Incidentally, component-embedded substrates are required to maintain sufficient conductivity in their wiring even after undergoing thermal processes such as reflow soldering. Therefore, in wiring layers formed using the above-mentioned wiring-forming materials, it is necessary that the connections made by conductive particles also maintain their conductivity well even under temperature changes and high temperatures.

[0005] For electrical connections, conductive particles are generally used that have been surface-treated to remove or prevent oxidation of the oxide film on the particle surface, from the viewpoint of conductivity and suppression of ion migration. However, when the inventors evaluated the connection resistance of a connector by applying a thermal history through repeated reflow resistance tests, they found that when conductive particles surface-treated with a surface treatment agent were used, the connection resistance value tended to increase compared to when conductive particles with only physical surface treatment were used.

[0006] Therefore, the present invention aims to provide surface-treated conductive particles and a method for manufacturing the same, as well as an adhesive composition and a wiring-forming member, which can provide a connector whose connection resistance value does not easily increase even when subjected to thermal history.

[0007] To solve the above problems, the inventors investigated different types of surface treatment agents for conductive particles and found that some agents tend to increase connection resistance when reflow resistance tests are repeated, while others do not. Based on this finding, the inventors completed the present invention.

[0008] In other words, the present invention includes the following aspects: [1] Conductive particles surface-treated with a surface treatment agent, wherein the surface treatment agent comprises a phosphate ester compound. [2] The surface-treated conductive particles according to [1], wherein the phosphate ester compound is a compound represented by the following general formula (P-1). [In formula (P-1), R represents an alkyl group having 1 to 8 carbon atoms, n represents an integer of 1 or 2, and if n is 2, the multiple Rs may be the same or different.] [3] An adhesive composition comprising the surface-treated conductive particles described in [1] or [2] and an adhesive component. [4] A wiring forming member comprising a metal layer and an adhesive layer formed from the adhesive composition described in [3] provided on the metal layer. [5] A method for producing surface-treated conductive particles, comprising step S of surface-treating conductive particles with a surface treatment agent containing a phosphate ester compound. [6] The method for producing surface-treated conductive particles according to [5], wherein the phosphate ester compound is a compound represented by the following general formula (P-1). [In formula (P-1), R represents an alkyl group having 1 to 8 carbon atoms, n represents an integer of 1 or 2, and if n is 2, the multiple Rs may be the same or different.] [7] A method for producing surface-treated conductive particles according to [5] or [6], further comprising: step A, which involves subjecting conductive particles X to an undercut treatment to remove small-diameter particles having a particle diameter of a predetermined value XU or less, before step S; and step B, which involves crushing the conductive particles A obtained through step A to obtain conductive particles B, wherein in step S, the conductive particles B are surface-treated with the surface treatment agent.

[0009] According to the present invention, it is possible to provide surface-treated conductive particles that can produce a connector whose connection resistance value does not easily increase even when subjected to thermal history, a method for manufacturing the same, an adhesive composition, and a wiring-forming member.

[0010] Figure 1 is a cross-sectional view showing a wiring forming member according to this embodiment.

[0011] Embodiments of the present invention will be described below. However, the present invention is not limited to the following embodiments.

[0012] In this specification, numerical ranges indicated using "~" represent a range that includes the numbers listed before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages within this specification, the upper or lower limit of one numerical range may be replaced by the upper or lower limit of another numerical range described in stages.

[0013] [Surface-treated conductive particles] The surface-treated conductive particles of this embodiment are conductive particles that have been surface-treated with a surface treatment agent, wherein the surface treatment agent contains a phosphate ester compound.

[0014] (Conductive Particles) Conductive particles may be metal particles composed of metals such as Au, Ag, Ni, Cu, Sn, or solder. Conductive particles may also be coated conductive particles comprising a core containing non-conductive glass, ceramic, or plastic (such as polystyrene), and a coating layer containing the above-mentioned metal that covers the core. Among these, conductive particles may also be metal particles formed from a heat-meltable metal, or coated conductive particles comprising a core containing plastic and a coating layer containing metal that covers the core. From the viewpoint of heat dissipation, conductive particles may also be copper particles.

[0015] Copper particles can be made containing one or more of Cu and alloys of Cu with other metals. Examples of alloys of Cu with other metals include silver, zinc, nickel, gold, lead, tin, aluminum, manganese, beryllium, tungsten, and iron. From the viewpoint of reducing connection resistance between wires and reducing manufacturing costs, the Cu content in the copper particles may be 50% by mass or more, 70% by mass or more, or 100% by mass.

[0016] In one embodiment, the conductive particles may include a core composed of polymer particles (plastic particles) such as polystyrene, and a metal layer covering the core. Substantially the entire surface of the polymer particle may be covered with the metal layer, or a part of the surface of the polymer particle may be exposed without being covered with the metal layer, as long as the function as a connecting material is maintained. The polymer particles may be, for example, particles containing a polymer comprising at least one monomer selected from styrene and divinylbenzene as a monomer unit.

[0017] The metal layer may be formed of various metals such as Ni, Ni / Au, Ni / Pd, Cu, NiB, Ag, and Ru. The metal layer may be an alloy layer made of an alloy of Ni and Au, an alloy of Ni and Pd, or the like. The metal layer may have a multilayer structure composed of a plurality of metal layers. For example, the metal layer may consist of a Ni layer and an Au layer. The metal layer may be produced by plating, vapor deposition, sputtering, soldering, or the like. The metal layer may be a thin film (for example, a thin film formed by plating, vapor deposition, sputtering, or the like).

[0018] The conductive particles may have an insulating layer. Specifically, for example, in a conductive particle including a core (e.g., polymer particle) and a coating layer such as a metal layer covering the core, an insulating layer that further covers the coating layer may be provided on the outside of the coating layer. The insulating layer may be the outermost surface layer located on the outermost surface of the conductive particle. The insulating layer may be a layer formed of an insulating material such as silica or acrylic resin.

[0019] The shape of the conductive particles may be spherical, substantially spherical, flaky, columnar, rod-shaped, needle-shaped, plate-shaped, or fibrous.

[0020] From the viewpoint of excellent dispersibility and conductivity, the average particle diameter of the conductive particles may be 1 μm or more, 2 μm or more, or 5 μm or more. From the viewpoint of excellent dispersibility and conductivity, the average particle diameter of the conductive particles may be 55 μm or less, 50 μm or less, 30 μm or less, or 20 μm or less. From the above viewpoints, the average particle diameter of the conductive particles may be 1 to 55 μm, 1 to 50 μm, 5 to 30 μm, 5 to 20 μm, or 2 to 20 μm.

[0021] In this specification, the average particle diameter of particles refers to the 50% cumulative particle diameter (D ５０ ) in the volume-based particle size distribution measured by laser diffraction / scattering particle size distribution measurement.

[0022] When the conductive particles are used for a wiring forming member or the like described later, the maximum particle diameter of the conductive particles may be smaller than the minimum interval between electrodes in a wiring pattern (the shortest distance between adjacent electrodes). From the viewpoint of excellent dispersibility and conductivity, the maximum particle diameter of the conductive particles may be 1 μm or more, 2 μm or more, or 5 μm or more. From the viewpoint of excellent dispersibility and conductivity, the maximum particle diameter of the conductive particles may be 55 μm or less, 50 μm or less, 30 μm or less, or 20 μm or less. From the above viewpoints, the maximum particle diameter of the conductive particles may be 1 to 55 μm, 1 to 50 μm, 2 to 30 μm, or 5 to 20 μm.

[0023] In this specification, for 1000 arbitrary particles (pcs), the particle diameter is measured by observation using a scanning electron microscope (SEM), and the maximum value obtained is defined as the maximum particle diameter of the particles. When the shape of the particle is not spherical, such as when the particle has protrusions, the particle diameter is defined as the diameter of a circle circumscribing the particle in an SEM image. In addition, for the observation of particles and measurement of particle diameter by SEM, a method of acquiring images in an automatic shooting mode of SEM and automatically analyzing the acquired image data with image processing software may be used.

[0024] The conductive particles may be surface-treated by a jet mill. In this case, the surface of the conductive particles can be modified. Examples of modification include removal of oxide films and leveling of the particle shape.

[0025] (Surface treatment agent) A phosphate ester compound can be used as a surface treatment agent.

[0026] Examples of phosphate ester compounds include those represented by the following general formula (P-1). [In formula (P-1), R represents an alkyl group having 1 to 8 carbon atoms, and n represents an integer of 1 or 2. When n is 2, the multiple R elements may be the same or different.]

[0027] The compound represented by the general formula (P-1) may have R be an ethyl group or a butyl group.

[0028] The compound represented by the general formula (P-1) may have n = 2.

[0029] Examples of phosphate ester compounds include butyl acid phosphate and ethyl acid phosphate.

[0030] For phosphate ester compounds, commercially available products such as "JP-504" (manufactured by Johoku Chemical Industry Co., Ltd., product name: butyl acid phosphate) and "JP-502" (manufactured by Johoku Chemical Industry Co., Ltd., product name: ethyl acid phosphate) can be used.

[0031] The phosphate ester compound may form a complex with metal atoms (e.g., copper atoms) present on the surface of the conductive particles.

[0032] The surface treatment of conductive particles can be performed, for example, by immersing the conductive particles in a surface treatment agent containing the above-mentioned phosphate ester compound and solvent, and stirring with an ultrasonic device if necessary.

[0033] The amount of surface treatment agent used may be 0.1 to 2.0 parts by mass, 3.0 to 6.0 parts by mass, or 8.0 to 10.0 parts by mass of the phosphate ester compound per 100 parts by mass of conductive particles.

[0034] The surface-treated conductive particles of this embodiment may be subjected to further surface treatments other than the surface treatment with the phosphate ester compound described above. Examples of such surface treatments include chelation treatment, metal coating by electroless plating, and metal film deposition by sputtering.

[0035] [Method for manufacturing surface-treated conductive particles] The method for manufacturing surface-treated conductive particles according to this embodiment comprises step S, which involves surface-treating conductive particles with a surface treatment agent containing a phosphate ester compound.

[0036] The conductive particles and phosphate ester compounds described above can be used.

[0037] The surface treatment agent may contain solvents such as acetone, isobutyl alcohol, 2-butanol, methanol, ethanol, and isopropyl alcohol. The solvent may be methanol, ethanol, or isopropyl alcohol.

[0038] The surface treatment in step S can be carried out in the same manner as described above. The amount of surface treatment agent used can also be the same as described above.

[0039] The method of this embodiment may further include, before step S, step A, in which conductive particles X are subjected to an undercut treatment to remove small-diameter particles having a particle diameter of a predetermined value XU or less, and step B, in which conductive particles A obtained through step A are crushed to obtain conductive particles B. In this case, in step S, conductive particles B are surface-treated with a surface treatment agent to obtain surface-treated conductive particles.

[0040] The conductive particles X may be metal particles such as Au, Ag, Ni, Cu, or solder. From the viewpoint of heat dissipation, copper particles can be used. The copper particles can be particles containing one or more of Cu and alloys of Cu with other metals. Examples of alloys of Cu with other metals include silver, zinc, nickel, gold, lead, tin, aluminum, manganese, beryllium, tungsten, and iron. The Cu content in the copper particles may be 50% by mass or more, 70% by mass or more, or 100% by mass.

[0041] The shape of the conductive particle X may be spherical, approximately spherical, flake-shaped, columnar, rod-shaped, needle-shaped, plate-shaped, or fibrous.

[0042] The conductive particle X may have a volume-reduced particle size distribution (hereinafter simply referred to as "volume-reduced particle size distribution") measured by laser diffraction / scattering particle size distribution measurement in the range of 20 to 80 μm, or in the range of 39 to 65 μm.

[0043] Conductive particle X has a 50% cumulative particle size in the volume-reduced particle size distribution (hereinafter referred to as "D"). Ｘ５０ In some cases, this may be the case.) However, it may also be 48-53 μm, 38-47 μm, or 54-64 μm.

[0044] Undercutting can be performed, for example, using a sieve with a classification mesh. The classification mesh can be made of metal such as stainless steel, or resin such as nylon. The sieve can be an ultrasonic sieve, an ultrasonic powder sieve, or a horizontal rotating sieve.

[0045] The opening diameter of the classification mesh can be appropriately set according to the particle size of the small particles to be removed. Furthermore, the frequency, intensity, and processing time of the sieve can be appropriately set according to the amount of small particles to be removed.

[0046] The undercutting process may include, for example, classification using a classification mesh having an aperture size of a predetermined value XU. The predetermined value XU is the D of the conductive particle X. Ｘ５０ It can be set using the following as an indicator. For example, the predetermined value XU is D Ｘ５０ The particle size may be 0.8 to 1.2 times that of D. Ｘ５０ The particle size may be 0.9 to 1.1 times that of D. Ｘ５０ The particle size may be 0.8 to 0.9 times that of the original particle.

[0047] D of conductive particle X Ｘ５０ If the following equation (X-1) is satisfied, then from the viewpoint of reducing the connection resistance, the predetermined value XU may satisfy the condition of the following equation (A-1): 40 μm ≤ D Ｘ５０ ≦55μm...(X-1) 0.8DＸ５０ ≦XU≦0.9D Ｘ５０ ...(A-1)

[0048] In step A, a top-cut treatment for removing large-diameter particles having a particle diameter of a predetermined value XT or more from the conductive particles X can be performed before or after the undercut treatment, or simultaneously with the undercut treatment.

[0049] For the top-cut treatment, the same means as the above-mentioned undercut treatment can be used.

[0050] The top-cut treatment may include classification with a classification mesh having an opening size of the predetermined value XT. The predetermined value XT is the D of the conductive particles X Ｘ５０ can be set using as an index. For example, the predetermined value XT is D Ｘ５０ may be 1.05 to 1.5 times the particle diameter, and D Ｘ５０ may be 1.1 to 1.3 times the particle diameter.

[0051] From the viewpoint of reducing the connection resistance value, the ratio of the 10% cumulative particle diameter to the 90% cumulative particle diameter in the volume-based particle size distribution [D Ａ１０ / D Ａ９０ may be 0.4 to 0.7, or may be 0.5 to 0.7.

[0052] For disintegrating the conductive particles A, for example, an airflow-type pulverizer such as a jet mill that can disintegrate particles only with compressed air can be used. Treatment conditions with a jet mill can be set so as to satisfy the following conditions.

[0053] For example, when AU is the cumulative frequency of particles having a particle diameter of a predetermined value XU or less in the volume-based particle size distribution of the conductive particles A, and BU is the cumulative frequency of particles having a particle diameter of a predetermined value XU or less in the volume-based particle size distribution of the conductive particles B, the conductive particles A may be disintegrated so as to satisfy the condition of the following formula (B-1). 10≦(BU-AU)≦40 ...(B-1)

[0054] In other words, by increasing the cumulative frequency of particles with a particle diameter of XU or less by 10 to 40%, the effect of reducing the connection resistance value by suppressing the flow of the resin component becomes easier to obtain. In addition, in step B, the cumulative frequency of particles with a particle diameter of XU or less may be increased by 10 to 20%.

[0055] Furthermore, from a similar viewpoint, the 10% cumulative particle size in the volume-reduced particle size distribution of conductive particle A and conductive particle B is set to D Ａ１０ and D Ｂ１０ In this case, conductive particles A may be crushed to satisfy the following condition (B-2): 10 ≤ (D Ａ１０ -D Ｂ１０ ) × 100 / D Ａ１０ ≦25...(B-2)

[0056] From the viewpoint of reducing connection resistance, step A, which satisfies the above-described equations (X-1) and (A-1), may be combined with step B, which satisfies the conditions of the above-described equation (B-1) or (B-2).

[0057] The conductive particles B obtained in step B may have a cumulative frequency of fine particles with a particle size smaller than a predetermined particle size S1 of less than 0.5%, and it is desirable that such particles are substantially absent, from the viewpoint of easily obtaining the effect of reducing connection resistance by suppressing the flow of the resin component. The particle size S1 may be, for example, the minimum diameter of the conductive particle X, or 2 to 5 μm.

[0058] When conductive particles A are crushed using a jet mill, the crushed material can be collected in a way that prevents the aforementioned fine particles from being included due to the airflow.

[0059] In step B, if the conductive particles are copper particles or the like, the oxide film on the particle surface can be removed. This reduces the volume resistivity of conductive particles B.

[0060] Furthermore, if the conductive particle X has impurities unevenly distributed on its surface, in step B, it is possible to obtain conductive particle B with a low concentration of impurities on its surface.

[0061] The conductive particles B obtained through step B have a ratio of 10% cumulative particle size to 90% cumulative particle size in the volume-converted particle size distribution [D Ｂ１０ / D Ｂ９０ ] may be between 0.4 and 0.7, and may be between 0.5 and 0.6.

[0062] [Adhesive Composition] The adhesive composition of this embodiment contains the surface-treated conductive particles of this embodiment and an adhesive component.

[0063] The adhesive component may be a thermosetting resin composition. Examples of components included in the thermosetting resin composition include a thermosetting resin, a curing agent, and a curing accelerator.

[0064] Thermosetting resins are resins that harden when heated. Examples of thermosetting resins include epoxy resins, polyimide resins, triazine resins such as melamine resins, phenolic resins, and modified versions of these resins. Among these, when used in components for forming wiring, as described later, epoxy resins may be preferred from the viewpoint of sufficiently suppressing the occurrence of bubbles or peeling during wiring formation.

[0065] When the adhesive component is used in wiring forming members, as described later, it may contain epoxy resin and phenolic resin as thermosetting components, from the viewpoint of sufficiently suppressing the occurrence of air bubbles or peeling during wiring formation and making it less likely for resistance unevenness to occur.

[0066] The epoxy resin can be any compound having two or more epoxy groups in its molecule, and examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, biphenyl novolac type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, naphthalene type polyfunctional epoxy resin, dicyclopentadiene type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, isocyanurate type epoxy resin, hydantoin type epoxy resin, glycidyl ether compounds of polyfunctional phenols, glycidyl ether compounds of difunctional alcohols, and hydrogenated versions thereof. Of these, from the viewpoint of ease of handling and availability, novolac type epoxy resins such as biphenyl novolac type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, or bisphenol F novolac type epoxy resin may be used. Epoxy resins may be used individually or in combination of two or more types.

[0067] The adhesive component may contain a compound having three or more epoxy groups in one molecule, as an epoxy resin, from the viewpoint of ensuring adhesive strength and heat resistance.

[0068] The epoxy resin may have an epoxy equivalent of 100 to 1000 g / eq, 125 to 900 g / eq, or 150 to 800 g / eq, from the viewpoint of ensuring adhesive strength, heat resistance, and good reactivity. The epoxy equivalent is determined by the method standardized in JIS standard (K7236:2001).

[0069] The epoxy resin content in the adhesive component may be 5 to 95% by mass, 10 to 90% by mass, 15 to 85% by mass, or 40 to 60% by mass, based on the total amount of adhesive component (total amount of solids other than conductive particles in the adhesive layer 10).

[0070] Phenolic resins function as curing agents for epoxy resins. Examples of phenolic resins include novolac-type phenolic resins such as phenol novolac, cresol novolac, bisphenol A novolac, bisphenol F novolac, and catechol novolac, as well as those in which the aromatic rings are substituted with alkyl groups. Phenolic resins may be used individually or in combination of two or more types.

[0071] The adhesive component may contain a compound having three or more phenol groups or cresol groups in one molecule as a phenol resin, from the viewpoint of ensuring adhesive strength and heat resistance. From the viewpoint of ease of handling and availability, such compounds may be phenol novolac type phenol resin, cresol novolac type phenol resin, bisphenol A novolac type phenol resin, or bisphenol F novolac type phenol resin.

[0072] The hydroxyl group equivalent of the phenolic resin may be 300 g / eq or less, or 250 g / eq or less, from the viewpoint of suppressing the occurrence of bubbles or peeling during wiring formation and making it less likely for resistance unevenness to occur. From the viewpoint of ease of handling and good reactivity, it may be 50 g / eq or more, or 100 g / eq or more.

[0073] The hydroxyl group equivalent of phenol resin is determined by the following measurement method. <Method for measuring hydroxyl group equivalent> Accurately weigh 1 g of the sample into a round-bottom flask, and then accurately weigh in 5 mL of acetic anhydride and pyridine reagent. Next, attach an air condenser to the flask and heat at 100°C for 1 hour. After the flask has cooled, add 1 mL of water and heat the flask again at 100°C for 10 minutes. After the flask has cooled again, wash the air condenser and the neck of the flask with 5 mL of neutralized methanol and add 1 mL of phenolphthalein reagent. The solution obtained in this way is titrated with a 0.1 mol / L potassium hydroxide-ethanol solution to determine the hydroxyl value. From the obtained hydroxyl value, calculate the hydroxyl group equivalent (g / eq) converted to the mass per 1 mol (1 eq) of hydroxyl groups.

[0074] The amount of phenolic resin in the adhesive component can be set so that the number of hydroxyl groups in the phenolic resin is 0.5 to 2 per epoxy group of the epoxy resin.

[0075] The adhesive component containing epoxy resin and phenolic resin may further contain thermosetting resins other than epoxy resin, and may further contain curing agents other than phenolic resin. Examples of thermosetting resins other than epoxy resin include polyimide resins, triazine resins such as melamine resins, and modified versions of these resins. Examples of curing agents other than phenolic resin include amines, amides, acid anhydrides, acids, and imidazoles.

[0076] Furthermore, when the adhesive component is used in wiring forming members as described later, it may further contain a maleimide compound from the viewpoint of sufficiently suppressing the occurrence of air bubbles or peeling during wiring formation.

[0077] In this case, from the viewpoint of sufficiently suppressing the occurrence of air bubbles or peeling during wiring formation, the adhesive component may contain epoxy resin as a thermosetting resin. The epoxy resin content in the adhesive component in this case may be 5 to 95% by mass, 10 to 90% by mass, 15 to 85% by mass, or 15 to 40% by mass, based on the total amount of adhesive component (total amount of solids other than conductive particles in the adhesive layer 10).

[0078] Maleimide compounds are compounds having at least one N-substituted maleimide group in one molecular structure. Maleimide compounds may include, for example, at least one selected from the group consisting of a polymaleimide compound (m1) having at least two N-substituted maleimide groups in one molecular structure (hereinafter sometimes referred to as "component (m1)") and its derivatives. Examples of "derivatives" include addition reaction products of the polymaleimide compound (m1) and amine compounds such as diamine compounds described later. Because maleimide compounds have low reactivity, it is expected that the curing reaction will proceed slowly when adhesive components contain them. By proceeding slowly, sufficient flow time can be secured, and the occurrence of bubbles or peeling during wiring formation can be sufficiently suppressed.

[0079] (m1) Examples of components include N,N'-ethylenebismaleimide, N,N'-hexamethylenebismaleimide, N,N'-(1,3-phenylene)bismaleimide, N,N'-[1,3-(2-methylphenylene)]bismaleimide, N,N'-[1,3-(4-methylphenylene)]bismaleimide, N,N'-(1,4-phenylene)bismaleimide, bis(4-maleimidophenyl)methane, bis(3-methyl-4-maleimidophenyl)methane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanebismaleimide, bis(4- Maleimidophenyl) ether, bis(4-maleimidophenyl) sulfone, bis(4-maleimidophenyl) sulfide, bis(4-maleimidophenyl) ketone, bis(4-maleimidocyclohexyl) methane, 1,4-bis(4-maleimidophenyl) cyclohexane, 1,4-bis(maleimidomethyl) cyclohexane, 1,4-bis(maleimidomethyl) benzene, 1,3-bis(4-maleimidophenoxy)benzene, 1,3-bis(3-maleimidophenoxy)benzene, bis[4-(3-maleimidophenoxy)phenyl] methane, bis[ 4-(4-maleimidophenoxy)phenyl]methane, 1,1-bis[4-(3-maleimidophenoxy)phenyl]ethane, 1,1-bis[4-(4-maleimidophenoxy)phenyl]ethane, 1,2-bis[4-(3-maleimidophenoxy)phenyl]ethane, 1,2-bis[4-(4-maleimidophenoxy)phenyl]ethane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]pig n, 2,2-bis[4-(4-maleimidophenoxy)phenyl]butane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 4,4-bis(3-maleimidophenoxy)biphenyl, 4,4-bis(4-maleimidophenoxy)biphenyl, bis[4-(3-maleimidophenoxy)phenyl]ketone, bis[4-(4-maleimidophenoxy)phenyl]ketone, 2,2-bis(4-maleimidophenyl) disulfide, bis(4-maleimidophenyl) disulfide, bis[4-(3-maleimidophenoxy)phenyl] sulfide, bis[4-(4-maleimidophenoxy)phenyl] sulfide, bis[4-(3-maleimidophenoxy)phenyl] sulfoxide, bis[4-(4-maleimidophenoxy)phenyl] sulfoxide, bis[4-(3-maleimidophenoxy)phenyl] sulfone, bis[4-(4-maleimidophenoxy)phenyl] sulfone, bis[4-(3-maleimidophenoxy)phenyl] ether, bis[4-(4-maleimidophenoxy)phenyl] ether, 1,4-bis[4-(4-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-maleimidophenoxy)-α,α Examples include -dimethylbenzylbenzene, 1,4-bis[4-(3-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(4-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, and polyphenylmethanemaleimide (for example, manufactured by Yamato Kasei Co., Ltd., trade name: BMI-2300, etc.). Maleimide compounds may be used individually or in combination of two or more.

[0080] Among these maleimide compounds, bis(4-maleimidophenyl)methane, bis(4-maleimidophenyl)sulfone, N,N'-(1,3-phenylene)bismaleimide, 2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, or polyphenylmethanemaleimide are preferred because they have a high reaction rate and can be made more heat resistant, and bis(4-maleimidophenyl)methane is particularly preferred from the viewpoint of solubility in solvents.

[0081] The maleimide compound may contain a derivative of the polymaleimide compound (m1) from the viewpoint of solubility in organic solvents, compatibility, and adhesion to metal foil. The derivative of the polymaleimide compound (m1) may include, for example, a modified polymaleimide compound (M) having a structural unit derived from the polymaleimide compound (m1) and a structural unit derived from an amine compound (m2) having an amino group (hereinafter sometimes referred to as "component (m2)"). The modified polymaleimide compound (M) can also be described as an addition reaction product of component (m1) and component (m2). The structural units derived from component (m1) and component (m2) contained in the modified polymaleimide compound (M) may each consist of one type or a combination of two or more types.

[0082] The modified polymaleimide compound (M) may be a compound containing a structure represented by the following formula (1), which is formed by an addition reaction between the maleimide group of component (m1) and the amino group of component (m2). In formula (1), * indicates the bond position.

[0083]

[0084] The (m2) component is preferably an amine compound (polyamine compound) having at least two amino groups, and may also be a diamine compound having two amino groups. Examples of the (m2) component include 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ketone, 4,4'-diaminobiphenyl, and 3,3'-dimethyl-4,4' -diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis(3-aminophenoxy)ben Zen, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 1,3-bis[1-[4-(4-aminophenoxy)phenyl]-1-methylethyl]benzene, 1,4-bis[1-[4-(4-aminophenoxy)phenyl]-1-methylethyl]benzene, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bis Aromatic diamine compounds such as aniline, 4,4'-[1,4-phenylenebis(1-methylethylidene)]bisaniline, 3,3'-[1,3-phenylenebis(1-methylethylidene)]bisaniline, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, and 9,9-bis(4-aminophenyl)fluorene; and amine compounds having a siloxane skeleton are examples.

[0085] Among these, component (m2) may be an amine compound having a siloxane skeleton from the viewpoint of low thermal expansion. In other words, the modified polymaleimide compound (M) may have structural units derived from the polymaleimide compound (m1) and structural units derived from an amine compound having a siloxane skeleton.

[0086] The (m2) component may be a compound represented by the following general formula (2).

[0087]

[0088] In formula (2), X ｂ４ This indicates a divalent organic group.

[0089] The (m2) component is X in the general formula (2) above, from the viewpoint of low thermal expansion. ｂ４ It may also contain an amine compound having a siloxane skeleton having a structural unit represented by the following general formula (3). In addition, component (m2) is X ｂ４ The compound may also contain an amine compound having a siloxane skeleton having a structural unit (or group) represented by the following general formula (4).

[0090]

[0091] In formula (3), R ｂ１６ and R ｂ１７ Each of these independently represents an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a substituted phenyl group. * indicates the bond position.

[0092]

[0093] In formula (4), R ｂ１６ and R ｂ１７ R in the above general formula (3) is ｂ１６ and R ｂ１７ It is synonymous with multiple R's. ｂ１６ and R ｂ１７ These may be the same or different. ｂ１８ and R ｂ１９ Each of these independently represents an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a substituted phenyl group. ｂ９ and X ｂ１０ Each independently represents a divalent organic group, n ｂ１３This represents an integer between 2 and 100.

[0094] R ｂ１６ , R ｂ１７ , R ｂ１８ , and R ｂ１９ Examples of substituents in the substituted phenyl group shown include C1-C5 alkyl groups, C2-C5 alkenyl groups, and C2-C5 alkynyl groups.

[0095] X ｂ９ and X ｂ１０ Examples of divalent organic groups include alkylene groups, alkenylene groups, alkynylene groups, arylene groups, -O- groups, or divalent linking groups formed by combinations of these.

[0096] The content of structural units derived from component (m1) in the modified polymaleimide compound (M) is not particularly limited, but may be 50 to 95% by mass, 70 to 92% by mass, or 75 to 90% by mass.

[0097] The content of structural units derived from component (m2) in the modified polymaleimide compound (M) is not particularly limited, but may be 5 to 50% by mass, 8 to 30% by mass, or 10 to 25% by mass.

[0098] The total content of structural units derived from component (m1) and component (m2) in the modified polymaleimide compound (M) is not particularly limited, but may be 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass (i.e., consisting only of structural units derived from component (m1) and component (m2)).

[0099] The maleimide compound content in the adhesive component may be 5 to 95% by mass, 10 to 90% by mass, or 15 to 85% by mass, based on the total amount of adhesive component (total amount of solids other than conductive particles in the adhesive layer 10).

[0100] Examples of curing accelerators include imidazole compounds, organophosphorus compounds, tertiary amines, and quaternary ammonium salts. A single curing accelerator may be used, or two or more may be used in combination. The adhesive component may contain an imidazole compound as a curing accelerator, from the viewpoint of allowing arbitrary adjustment of the temperature and time during use (e.g., heating temperature and time during heat bonding).

[0101] The content of the curing accelerator in the adhesive component may be 0.001 to 10% by mass, based on the total amount of the adhesive component.

[0102] The adhesive components may contain other components besides the thermosetting components mentioned above. These other components may include fillers, antioxidants, film-forming agents, softeners, anti-aging agents, colorants, flame retardants, thixotropic agents, coupling agents, and the like.

[0103] Examples of fillers include inorganic fillers and organic fillers. Examples of inorganic fillers include alumina, silica, titanium dioxide, clay, calcium carbonate, aluminum carbonate, magnesium silicate, aluminum silicate, mica, glass short fibers, aluminum borate, silicon carbide, etc. Examples of organic fillers include silicone particles, methacrylate / butadiene / styrene particles, acrylic / silicone particles, polyamide particles, polyimide particles, etc. Fillers may be used individually or in combination of two or more types.

[0104] The adhesive component may contain silica particles as a filler, from the viewpoint of improving heat resistance, improving mechanical properties, and adjusting fluidity during use (for example, during heat bonding).

[0105] The maximum diameter of the filler may be less than the particle size of the conductive particles, and may be between 0.001 and 10 μm.

[0106] The filler content may be 5 to 60 parts by volume per 100 parts by volume of adhesive component. When the filler content is 5 to 60 parts by volume, good connection reliability tends to be obtained.

[0107] Examples of antioxidants include quinone derivatives such as benzoquinone and hydroquinone, phenol derivatives (hindered phenol derivatives) such as 4-methoxyphenol and 4-t-butylcatechol, aminooxyl derivatives such as 2,2,6,6-tetramethylpiperidine-1-oxyl and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, and hindered amine derivatives such as tetramethylpiperidyl methacrylate.

[0108] The antioxidant content may be 0.01% to 5% by mass, or 0.1% to 3% by mass, based on the total amount of adhesive components.

[0109] Suitable film-forming materials include thermoplastic resins such as phenoxy resin, polyvinyl formal resin, polystyrene resin, polyvinyl butyral resin, polyester resin, polyamide resin, xylene resin, polyurethane resin, polyacrylic resin, and polyester urethane resin. Furthermore, these polymers may contain siloxane bonds or fluorine substituents. These resins can be used individually or in mixtures of two or more. Among the above resins, phenoxy resin may be used from the viewpoint of adhesive strength, compatibility, heat resistance, and mechanical strength.

[0110] The larger the molecular weight of the thermoplastic resin, the easier it is to obtain film-forming properties, and the wider the range of melt viscosity that affects the fluidity of the film. The molecular weight of the thermoplastic resin may be 5,000 to 150,000 or 10,000 to 80,000 in weight-average molecular weight. Good film-forming properties are easily obtained by setting the weight-average molecular weight to 5,000 or higher, and good compatibility with other components is easily obtained by setting it to 150,000 or lower.

[0111] In this disclosure, weight-average molecular weight refers to the value measured using a calibration curve with standard polystyrene from a gel permeation chromatograph (GPC) according to the following conditions: (Measurement conditions) Apparatus: GPC-8020 manufactured by Tosoh Corporation Detector: RI-8020 manufactured by Tosoh Corporation Column: Gelpack GLA160S + GLA150S manufactured by Resonaq Corporation Sample concentration: 120 mg / 3 mL Solvent: Tetrahydrofuran Injection volume: 60 μL Pressure: 2.94 × 10⁶ Pa (30 kgf / cm²) ２ ) Flow rate: 1.00mL / min

[0112] Furthermore, the content of the film-forming material may be 0.5 to 75% by mass or 1 to 50% by mass, based on the total amount of adhesive components.

[0113] The adhesive components may substantially contain highly reactive radical polymerizable compounds such as acrylic compounds, methacrylic compounds, styrene compounds, and vinyl compounds, from the viewpoint of improving storage stability and connection reliability. "Substantially contained" means that the content, based on the total amount of adhesive components, is 1% by mass or less. The content of the above compounds in the adhesive components may be 0.5% by mass or less, or even 0% by mass, based on the total amount of adhesive components.

[0114] The content of the surface-treated conductive particles in the adhesive composition of this embodiment may be 0.5 to 15% by volume or 0.5 to 10% by volume, based on the total volume of the adhesive composition, from the viewpoint of reducing the connection resistance.

[0115] The adhesive composition of this embodiment can be used to form an adhesive layer in a wiring forming member, which will be described later.

[0116] Furthermore, the adhesive composition of this embodiment may also be used as an adhesive film formed into a film. Such an adhesive film can be used to connect circuit members and can be suitably used as a circuit connection adhesive film for connecting a first circuit member having a first electrode (for example, a first circuit member in which the first circuit electrode is formed on the main surface of a first substrate) and a second circuit member having a second electrode (for example, a second circuit member in which the second circuit electrode is formed on the main surface of a second substrate) with the first electrode and the second electrode (the first circuit electrode and the second circuit electrode) facing each other.

[0117] Examples of the first and second circuit components include chip components such as semiconductor chips, resistor chips, and capacitor chips, and circuit boards such as printed circuit boards.

[0118] Adhesive films can be manufactured by the following method. Specifically, first, adhesive components and surface-treated conductive particles are added to a solvent (organic solvent) and dissolved or dispersed by stirring, mixing, kneading, etc., to prepare a varnish composition (varnish-like adhesive composition). Then, the varnish composition is applied to a substrate that has been treated with a release agent using a knife coater, roll coater, applicator, comma coater, die coater, etc., and the solvent is evaporated by heating to form an adhesive film on the substrate.

[0119] The solvent used in preparing the varnish composition may be one that has the property of uniformly dissolving or dispersing each component. Examples of such solvents include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, and butyl acetate. These solvents can be used individually or in combination of two or more. The stirring, mixing, and kneading during the preparation of the varnish composition can be carried out using, for example, a stirrer, a sieve, a three-roll mill, a ball mill, a bead mill, or a homodisper.

[0120] The substrate is not particularly limited as long as it has heat resistance that can withstand the heating conditions when the solvent is evaporated. For example, substrates (e.g., films) made of stretched polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, liquid crystal polymer, etc., can be used.

[0121] [Wiring Forming Member] The wiring forming member of this embodiment comprises a metal layer and an adhesive layer formed from the adhesive composition of this embodiment, which is provided on the metal layer.

[0122] Figure 1 is a cross-sectional view showing a wiring-forming member according to this embodiment. As shown in Figure 1, the wiring-forming member 1 comprises an adhesive layer 10 and a metal layer 20. The wiring-forming member 1 is not limited to these, but can be used, for example, when manufacturing a rewiring layer, a build-up multilayer wiring board, and a component-embedded substrate. The wiring-forming member 1 may also be used for EMI shielding and the like.

[0123] (Adhesive layer) The adhesive layer 10 is formed from the adhesive composition of this embodiment and includes surface-treated conductive particles 12 and adhesive components 14. The adhesive layer 10 may be in a B-stage state, i.e., a semi-cured state, before the wiring layer is formed by the wiring forming member 1.

[0124] The content of surface-treated conductive particles 12 is determined according to the fineness of the electrodes to be connected. For example, there are no particular restrictions on the amount of surface-treated conductive particles 12 added, but it may be 0.1 volume% or more, 0.2 volume% or more, 1 volume% or more, 1.5 volume% or more, 2 volume% or more, 5 volume% or more, or 10 volume% or more, based on the total volume of the adhesive components (components in the adhesive composition excluding conductive particles). When the above amounts are within these ranges, resistance unevenness and low conductivity tend to be suppressed. The amount of surface-treated conductive particles 12 added may be 30 volume% or less, 15 volume% or less, or 10 volume% or less, based on the total volume of the adhesive components (components in the adhesive composition excluding conductive particles). When the above amounts are within these ranges, short circuits tend to be less likely to occur. Note that "volume%" is determined based on the volume of each component before curing at 23°C, but the volume of each component can be converted from weight to volume using specific gravity. Alternatively, instead of dissolving or swelling the component in a graduated cylinder, one can add the component to a suitable solvent (such as water or alcohol) that thoroughly wets the component, and measure the increase in volume as the volume of the component.

[0125] The thickness of the adhesive layer may be 1 to 70 μm, 2 to 60 μm, or 3 to 50 μm.

[0126] From the perspective of minimizing resistance unevenness, the average particle size D of the surface-treated conductive particles. ５０ The ratio of the thickness T of the adhesive layer to [D ５０ / T] may be 0.05 to 1, 0.2 to 0.8, or 0.35 to 0.65.

[0127] The adhesive layer can be fabricated on the metal layer using the varnish-like adhesive composition described above, in the same manner as described above.

[0128] In the adhesive layer 10 shown in Figure 1, the surface-treated conductive particles 12 are randomly or evenly dispersed, but the surface-treated conductive particles 12 may be positioned (unevenly distributed) on the metal layer 20 side. In this case, the surface-treated conductive particles 12 are not exposed on the second surface 10b opposite to the metal layer 20, and the thickness of the adhesive layer 10 between the surface-treated conductive particles 12 and the first surface 20a of the metal layer 20 (or the first surface 10a of the adhesive layer 10) may be greater than 0 μm or 0.1 μm and less than or equal to 1 μm.

[0129] (Metal layer) The metal layer 20 may be, for example, copper foil, aluminum foil, nickel foil, stainless steel, titanium, or platinum.

[0130] The surface roughness Rz of one surface and the opposite surface of the metal layer 20 may be the same, or they may be different. The metal layer 20 has a thickness of, for example, 5 μm to 200 μm. The thickness of the metal layer referred to here includes the surface roughness Rz.

[0131] An adhesive layer 10 is disposed on the first surface 20a of the metal layer 20. The surface roughness Rz of the first surface 20a of the metal layer 20 may be 0.3 μm or more, 0.5 μm or more, or 1.0 μm or more. Also, the surface roughness Rz of the first surface 20a of the metal layer 20 may be 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, less than 20 μm, 17 μm or less, 10 μm or less, 8.0 μm or less, 5.0 μm or less, or 3.0 μm or less. For example, the surface roughness Rz of the first surface 20a of the metal layer 20 may be 0.3 μm or more and 20 μm or less, 0.3 μm or more and less than 20 μm, and more specifically, 0.5 μm or more and 10 μm or less. The surface roughness Rz of the second surface 20b of the metal layer 20 may be, for example, 20 μm or more, and may be rougher than the surface roughness Rz of the first surface 20a, or may be the same as the surface roughness of the first surface 20a, or may not be rougher than the surface roughness Rz of the first surface 20a. If the surface roughness Rz of the first surface 20a of the metal layer 20 is too smooth (for example, the surface roughness Rz is 0.2 μm), the adhesion between the metal layer 20 and the adhesive layer 10 may not be maintained over a long period of time and may peel off. For this reason, the surface roughness Rz of the first surface 20a of the metal layer 20 may be 0.3 μm or more. However, by employing a material or connection configuration that can ensure adhesion, the surface roughness Rz of the first surface 20a of the metal layer 20 may be less than 0.3 μm.

[0132] Surface roughness Rz refers to the ten-point average roughness Rzjis measured according to the method specified in the JIS standard (JIS B 0601-2001), and is a value measured using a commercially available surface roughness shape measuring instrument. For example, it can be measured using a nanosearch microscope (Shimadzu Corporation's "SFT-3500").

[0133] Here, the average particle size D of the surface-treated conductive particles 12 ５０The ratio of the surface roughness Rz of the first surface 20a of the metal layer 20 to the surface roughness Rz, known as "surface roughness / average particle size," may be 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.1 or more, 0.2 or more, 0.3 or more, 0.5 or more, or 1 or more. Furthermore, the above "surface roughness / average particle size" may be 3 or less, 2 or less, 1.7 or less, or 1.5 or less. In addition, the above "surface roughness / average particle size" may be, for example, 0.05 or more and 3 or less, or 0.06 or more and 2 or less.

[0134] A method for forming a wiring layer using a wiring-forming member may include the steps of: preparing a wiring-forming member; preparing a substrate on which wiring is formed; arranging the wiring-forming member on the surface of the substrate on which wiring is formed so as to cover the wiring, with the adhesive layer side facing the substrate; heat-pressing the wiring-forming member onto the substrate; and performing a patterning treatment on the metal layer.

[0135] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples.

[0136] <Preparation of Conductive Particles> [Preparation of Copper Particle X] Commercially available copper particles were prepared as copper particle X, and the volume-reduced particle size distribution was measured by laser diffraction / scattering particle size distribution measurement, and the following information was obtained: Minimum diameter: 6.7 μm Maximum diameter: 262.4 μm 10% cumulative particle size: 19.4 μm 50% cumulative particle size: 43.8 μm 90% cumulative particle size: 81.1 μm

[0137] [Step A] The copper particles X prepared above were subjected to the following top-cut treatment. <Top-cut treatment> Sieve: Ultrasonic sieve (manufactured by Tsutsui Rikagakuki Co., Ltd., SW-20AT, frequency 115 Hz, LEVEL (7), treatment time 15 minutes) Classification mesh: Stainless steel mesh (aperture size: 53 μm) / Nylon mesh (aperture size: 48 μm) / Stainless steel mesh (aperture size: 46 μm)

[0138] Next, the following undercutting process was performed. <Undercutting Process> Sieving equipment: Ultrasonic powder sieving equipment (Artech Co., Ltd., DGS35-50, frequency 35kHz, LEVEL 80%, processing time 15 minutes) + horizontal swivel sieving equipment (Taiyo Co., Ltd., SKH-01, rotation speed 200rpm, processing time 15 minutes) Classification mesh: Stainless steel mesh (aperture size: 38μm)

[0139] The volume-reduced particle size distribution of copper particles A obtained through the above process was measured by laser diffraction / scattering particle size distribution measurement, and the following information was obtained: Minimum diameter: 29.9 μm Maximum diameter: 116.2 μm 10% cumulative particle size: 40.2 μm 50% cumulative particle size: 51.2 μm 90% cumulative particle size: 67.3 μm

[0140] [Step B] The copper particles A obtained above were crushed using a Super Jet Mill SJ-100 (manufactured by Nisshin Engineering Co., Ltd.) under the conditions of an air pressure of 0.5 MPa and a processing time of 10 g / min.

[0141] The volume-reduced particle size distribution of copper particles B obtained through the above process was measured by laser diffraction / scattering particle size distribution measurement, and the following information was obtained: Minimum diameter: 22.8 μm Maximum diameter: 116.2 μm 10% cumulative particle size: 33.1 μm 50% cumulative particle size: 43.1 μm 90% cumulative particle size: 58.1 μm

[0142] Furthermore, the cumulative frequency of copper particle B particles between 22.8 μm and 26.1 μm in the volume-reduced particle size distribution was 0.8%. In addition, step B increased the cumulative frequency of copper particle B particles 38 μm or smaller in the volume-reduced particle size distribution by 12% compared to the cumulative frequency of copper particle A particles 38 μm or smaller in the volume-reduced particle size distribution.

[0143] <Preparation of surface-treated conductive particles and wiring-forming components> (Example 1) To 100 g of copper particles B obtained above, 1.0 g of "JP-504" (manufactured by Johoku Chemical Industry Co., Ltd., product name: butyl acid phosphate) as a phosphate ester compound and a surface treatment agent containing methanol were mixed and stirred using an ultrasonic device to obtain surface-treated copper particles 1.

[0144] Next, as epoxy resins, 5.00 g of NC-3000H (biphenyl aralkyl type epoxy resin, manufactured by Nippon Kayaku Co., Ltd., trade name, epoxy equivalent: 289 g / eq) and 4.69 g of YL983U (bisphenol F type epoxy resin, manufactured by Mitsubishi Chemical Corporation, trade name, epoxy equivalent: 170 g / eq) were added, as phenol resins, 4.08 g of KA-1163 (cresol novolac type phenol resin, manufactured by DIC Corporation, trade name, hydroxyl group equivalent: 118 g / eq) were added, and as phenoxy resins, YP-70 (BPA / BP 2.68 g of F copolymer (manufactured by Nippon Steel Chemical & Material Co., Ltd., trade name) and 0.025 g of G-8009L (isocyanate mucimidazole, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name) as a curing accelerator were dissolved in 19.1 g of methyl ethyl ketone (MEK). Then, 5.36 g of SC-2050KC (phenylaminosilane-treated silica filler, average particle size 0.5 μm, manufactured by Admatex Co., Ltd., trade name) and 4.21 g of surface-treated copper particles 1 were added to prepare a coating solution for forming an adhesive layer.

[0145] This coating solution was applied to one side (surface roughness Rz: 3.0 μm) of copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd., product name: "3EC-M3-VLP", thickness: 12 μm) using a coating device (manufactured by Yasui Seiki Co., Ltd., product name: Precision Coating Machine), and then dried with hot air at 70°C for 5 minutes to form an adhesive layer with a thickness of 54 μm on the copper foil. In this way, a component for forming wiring was manufactured.

[0146] (Comparative Example 1) Surface-treated copper particles C1 were obtained in the same manner as in Example 1, except that 10 g of the copper discoloration inhibitor "BT-5" (manufactured by ASAHI Corporation, product name) was used instead of the phosphate ester compound "JP-504".

[0147] A wiring forming member was manufactured in the same manner as in Example 1, except that surface-treated copper particles C1 were used instead of surface-treated copper particles 1.

[0148] (Comparative Example 2) Surface-treated copper particles C2 were obtained in the same manner as in Example 1, except that 10 g of the copper discoloration inhibitor "BT-7" (manufactured by ASAHI Corporation, product name) was used instead of the phosphate ester compound "JP-504".

[0149] A wiring forming member was manufactured in the same manner as in Example 1, except that surface-treated copper particles C2 were used instead of surface-treated copper particles 1.

[0150] (Comparative Example 3) Surface-treated copper particles C3 were obtained in the same manner as in Example 1, except that 10 g of the copper discoloration inhibitor "BT-8" (manufactured by ASAHI Corporation, product name) was used instead of the phosphate ester compound "JP-504".

[0151] A wiring forming member was manufactured in the same manner as in Example 1, except that surface-treated copper particles C3 were used instead of surface-treated copper particles 1.

[0152] [Evaluation of Wiring Forming Components] For the wiring forming components prepared as described above, evaluation samples were prepared and their connection resistance values ​​were measured according to the following method, and the connection resistance values ​​were evaluated according to the following criteria.

[0153] [Measurement of connection resistance] <Preparation of evaluation sample> Wiring forming material was attached to a circuit board (PWB) having three copper circuits with a line width of 1000 μm, a pitch of 10000 μm, and a thickness of 15 μm on a glass cloth-reinforced epoxy substrate. This was then heated and pressurized at 180°C and 2 MPa for 60 minutes using a thermocompression bonding device (heating method: constant heat type, manufactured by Toray Engineering Co., Ltd.) to connect them over a width of 2 mm and to produce a connected body.

[0154] The sample, with a resist formed on the fabricated connector, was immersed in an etching solution and agitated. The etching solution was prepared with copper chloride: 100 g / L and hydrochloric acid: 100 ml / L. Once the desired copper foil portion was removed, it was washed with pure water. After that, the resist was peeled off to obtain the desired evaluation sample.

[0155] <Evaluation of the initial evaluation sample> The resistance between the remaining copper foil portion on the circuit and the copper circuit on the substrate was measured with a multimeter immediately after bonding. The connection resistance value was calculated by taking the average of 37 resistance points between the remaining copper foil portion on the circuit and the copper circuit on the substrate, and evaluated according to the following criteria.

[0156] [Criteria for determining connection resistance] A: Average resistance value is 0.5 mΩ or less B: Average resistance value is greater than 0.5 mΩ and 1.5 mΩ or less C: Average resistance value is greater than 1.5 mΩ and 2.5 mΩ or less D: Average resistance value is greater than 2.5 mΩ

[0157] <Evaluation of the evaluation sample (after reflow test)> The evaluation sample was passed through a reflow process with the following temperature profile once, three times, and six times. The connection resistance value was then measured in the same manner as above and evaluated according to the above criteria. Temperature profile: Heating from 50°C to 150°C at a heating rate of 2°C / second, holding at 150°C for 100 seconds, then heating from 150°C to 245°C at a heating rate of 1°C / second, holding at 245°C for 50 seconds, and then cooling from 245°C to 40°C.

[0158]

[0159] 1...Wiring forming member, 10...Adhesive layer, 10a...First surface, 10b...Second surface, 12...Surface-treated conductive particles, 14...Adhesive component, 20...Metal layer, 20a...First surface, 20b...Second surface.

Claims

1. Conductive particles surface-treated with a surface treatment agent, wherein the surface treatment agent contains a phosphate ester compound.

2. The surface-treated conductive particle according to claim 1, wherein the phosphate ester compound is a compound represented by the following general formula (P-1). [In formula (P-1), R represents an alkyl group having 1 to 8 carbon atoms, and n represents an integer of 1 or 2. When n is 2, the multiple R elements may be the same or different.] 3. An adhesive composition comprising surface-treated conductive particles according to claim 1 or 2 and an adhesive component.

4. A wiring forming member comprising a metal layer and an adhesive layer provided on the metal layer, which is formed from the adhesive composition described in claim 3.

5. A method for producing surface-treated conductive particles, comprising step S of surface-treating conductive particles with a surface treatment agent containing a phosphate ester compound.

6. The method for producing surface-treated conductive particles according to claim 5, wherein the phosphate ester compound is a compound represented by the following general formula (P-1). [In formula (P-1), R represents an alkyl group having 1 to 8 carbon atoms, and n represents an integer of 1 or 2. When n is 2, the multiple R elements may be the same or different.] 7. A method for producing surface-treated conductive particles according to claim 5, further comprising: step A, before step S, an undercut treatment being performed on conductive particles X to remove small-diameter particles having a particle diameter of a predetermined value XU or less; and step B, the conductive particles A obtained through step A being crushed to obtain conductive particles B, wherein in step S, the conductive particles B are surface-treated with the surface treatment agent.

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