Oxide-containing plate-shaped copper particles, paste composition, semiconductor device, electrical component and electronic component

Abstract

The present invention provides: oxide-containing plate-like copper particles which enable the achievement of a paste composition that is capable of forming a bonding layer having high denseness, high bonding strength and high bonding reliability; a paste composition which uses the oxide-containing plate-like copper particles; and a semiconductor device, an electrical component and an electronic component. Copper oxide-containing plate-like copper particles according to the present disclosure contain Cu, Cu2O and Cu64O; and the content of Cu64O is 2.1% by mass to 25.0% by mass relative to a total of 100% by mass of Cu, Cu2O and Cu64O.

Description

[Technical Field]

[0001] The present disclosure relates to oxide-containing plate-like copper particles, a paste composition using the same, and semiconductor devices, electrical components, and electronic components. [Background technology]

[0002] 2. Description of the Related Art In semiconductor devices and various electric and electronic components, highly thermally conductive pastes are used as adhesives for joining various components together. In semiconductor devices, heat generation is increasing due to higher integration and higher operating speeds, and in order to ensure stable operation, measures have been taken to dissipate heat, such as bonding heat-generating components such as semiconductor elements to heat-dissipating components with a highly thermally conductive adhesive (paste). Also, highly thermally conductive pastes are used for die-bonding bare chips, bonding LED chips, or bonding electrodes and lead wires.

[0003] A paste composition containing copper particles has been proposed as one type of conductive paste with high thermal conductivity. The application of such a paste composition to printed electronics is also being considered. For example, Patent Documents 1 and 2 disclose that oxide-containing copper particles obtained by sintering a copper raw material at a low temperature are used as a constituent material of a conductive paste. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-29392 [Patent Document 2] International Publication No. 2022 / 045252 Summary of the Invention

[0005] The present disclosure relates to the following: [1] Cu, Cu2O and Cu 64 Contains O and Cu 64 The content of O is Cu, Cu2O and Cu 64Copper oxide-containing plate-like copper particles, with the content of O being 2.1 to 25.0 mass % relative to 100 mass % of the total. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is an image of the oxide-containing plate-like copper particles of Example 4 observed by a scanning electron microscope. [Figure 2] 1 is an image of oxide-containing copper particles of Comparative Example 2 observed with a scanning electron microscope. DETAILED DESCRIPTION OF THE INVENTION

[0007] The conductive pastes using oxide-containing copper particles as described in Patent Documents 1 and 2 have roughly spherical particles, which can lead to voids in the bonding layer when sintered and bonded, resulting in low density and difficulty in obtaining sufficient bonding strength, which can lead to low bonding reliability.

[0008] The present disclosure relates to oxide-containing copper particles that can provide a paste composition capable of forming a bonding layer that has high density, high bonding strength, and high bonding reliability, as well as a paste composition using the same, and a semiconductor device, an electrical component, and an electronic component.

[0009] Hereinafter, the present disclosure will be described in detail with reference to an embodiment. The oxide-containing plate-like copper particles in the present disclosure refer to particles that contain metallic copper and at least one copper oxide and have a plate-like particle shape. Hereinafter, they may also be simply referred to as copper particles.

[0010] In this specification, the expression "XX to YY" means "XX or more and YY or less." In addition, in this specification, for a numerical range (for example, a range of content, etc.), the lower limit and upper limit values ​​described in stages can be independently combined. In addition, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with a value shown in the examples.

[0011] [Oxide-containing plate-shaped copper particles] The oxide-containing plate-like copper particles of the present disclosure are composed of Cu, CuO and Cu 64 Contains O and Cu 64 The content of O is Cu, Cu2O and Cu 64 The content is 2.1 to 25.0 mass % relative to a total of 100 mass % of O. The copper particles of the present disclosure are composed of Cu and copper oxides CuO and Cu 64 It contains O, which has good sinterability and reducibility. 64 When the O content is within the above range, it is possible to obtain a paste composition that can form a bonding layer that has high density, high bonding strength, and high bonding reliability.

[0012] Cu 64 Compared with CuO and Cu2O, O has a lower oxygen atom ratio and lower phase stability. 64 If the O content is high, self-oxidation decomposition occurs easily during sintering, making it difficult to reduce, while Cu is easily decomposed by heating. 64 It is believed that the copper atoms that make up O become more likely to move or diffuse, accelerating sintering. Cu 64 If the O content is 2.1 mass% or more, Cu 64 The migration or diffusion of copper atoms that make up O facilitates sintering. 64 If the O content is 25.0 mass% or less, Cu 64 O is sufficiently reduced, and copper particles with good sinterability are obtained. Cu 64 The O content may be 2.5 to 25.0 mass %, or 3.0 to 20.0 mass %.

[0013] The copper particles contain CuO, and the content thereof is set to Cu, CuO and Cu from the viewpoint of good sinterability of the copper particles. 64 With respect to a total of 100% by mass of O, the content may be 5.0% by mass or less, may be 0.1 to 4.5% by mass, or may be 1.0 to 4.0% by mass.

[0014] Cu in copper particles, Cu64 Cu relative to 100% by mass of the total of O and Cu2O 64 The contents of O and CuO are determined from the X-ray diffraction (XRD) pattern by the reference intensity ratio (RIR) method. The XRD pattern is obtained by irradiating characteristic X-rays of CuKα rays (wavelength 0.15418 nm) and performing XRD measurement. Specifically, it is measured by the method described in the Examples. In the XRD pattern, the strongest rays of each component (Cu(111), Cu 64 For CuO(044) and CuO(111), the integrated intensity after subtracting the background intensity and each RIR value (Cu: 8.86, Cu 64 The diffraction angle 2θ of each peak is 43.298° for Cu(111), 43.298° for Cu(111), 43.298° for Cu(111), and 43.298° for Cu(111). 64 O(044) is 40.710° and Cu2O(111) is 36.419°.

[0015] The copper particles may have a ratio (C2 / C1) of 2.0 or more of the Cu(111) crystallite size (C2) after heating to the Cu(111) crystallite size (C1) before heating when heated at 200°C in a nitrogen atmosphere. That is, from the viewpoints of sinterability, compactness, and bonding strength, the ratio C2 / C1 of the Cu(111) crystallite sizes before and after heating at 200°C in a nitrogen atmosphere may be 2.0 or more, 3.0 to 10.0, or 4.0 to 8.0.

[0016] From a practical standpoint, heating at 200°C under a nitrogen atmosphere is a heating condition that takes into account the atmosphere and temperature when using a paste composition containing copper particles as a joining material and joining is performed by sintering the copper particles.

[0017] The crystallite diameter (C2) may be 55.0 nm or more, may be 57.0 to 80.0 nm, or may be 58.0 to 75.0 nm, from the viewpoints of sinterability, compactness, and bonding strength.

[0018] The crystallite size (C1) may be 5.0 to 30.0 nm, 7.0 to 25.0 nm, or 8.0 to 20.0 nm, from the viewpoints of sinterability, compactness, and bonding strength.

[0019] The crystallite size of Cu(111) of the copper particles can be determined from the XRD pattern, specifically by the method described in the Examples.

[0020] The copper particles are plate-shaped particles. The thickness of the copper particles may be 5 to 50 nm, 8 to 40 nm, or 10 to 30 nm. The copper particles may have a major axis of 30 to 300 nm, 50 to 200 nm, or 75 to 150 nm, and the major axis may be greater than the thickness.

[0021] The aspect ratio (major axis / thickness) of the copper particles may be 1.5 to 10.0, 2.0 to 9.0, or 3.0 to 8.0.

[0022] Since the copper particles are plate-shaped particles, the contact area between the particles is larger than that of spherical particles. It is presumed that the bonding layer formed from the paste composition using the plate-shaped particles has a high density, high bonding strength, and is likely to have high bonding reliability.

[0023] The thickness and major axis of the copper particles are the median values ​​of the measured lengths of at least 200 particles extracted from images taken by scanning electron microscope (SEM) observation. Specifically, the thickness and major axis of the copper particles can be measured by the method described in the Examples. The plate-like particles have a shape with a pair of approximately parallel flat surfaces, and the distance between the pair of flat surfaces is defined as the "thickness" and the longest diameter on the flat surfaces is defined as the "major axis."

[0024] The copper particles are usually sintered by heating at 100 to 250° C. in an inert gas atmosphere. Examples of inert gases include nitrogen, argon, helium, etc. Nitrogen may be used from the viewpoint of availability and cost. The heating temperature may be 120 to 230°C, or 150 to 200°C, from the viewpoint of good sinterability. The sintering may be carried out under normal pressure or under pressure. The heating time is appropriately set depending on the heating temperature, the shape of the sintered body, etc. From the viewpoint of sufficient sintering progress, the heating time may be, for example, 5 to 180 minutes, 10 to 120 minutes, or 30 to 90 minutes.

[0025] [Method of manufacturing oxide-containing plate-like copper particles] The method for producing oxide-containing plate-like copper particles of the present disclosure is not particularly limited.For example, a method of reducing a copper compound using a reducing compound in the presence of a shape stabilizer can be mentioned.The copper compound, the shape stabilizer and the reducing compound can be mixed in an organic solvent.

[0026] (copper compound) Examples of copper compounds include copper oxide, copper hydroxide, copper nitride, and copper carboxylate. The copper compound may be copper oxide, from the viewpoint of obtaining the copper particles of the present disclosure in high yield. The copper compounds may be used alone or in combination of two or more.

[0027] Examples of copper oxide include copper(I) oxide (cuprous oxide: CuO) and copper(II) oxide (CuO). From the viewpoint of productivity, copper(I) oxide may be used. Examples of copper hydroxide include copper(II) hydroxide and copper(I) hydroxide. Examples of copper nitride include copper(II) nitride and copper(I) nitride. Examples of copper carboxylates include copper(I) formate, copper(I) acetate, copper(I) propionate, copper(I) butyrate, copper(I) valerate, copper(I) hexanoate, copper(I) octanoate, and copper(I) decanoate, as well as copper carboxylate anhydrides or hydrates such as copper(II) formate, copper(II) acetate, copper(II) propionate, copper(II) butyrate, copper(II) valerate, copper(II) hexanoate, copper(II) octanoate, copper(II) decanoate, and copper(II) citrate. Commercially available copper carboxylates may be used. Copper carboxylates synthesized by known methods may also be used. From the viewpoints of availability and the production efficiency of the copper particles of the present disclosure, the copper carboxylate may be copper(II) acetate monohydrate.

[0028] (shape stabilizer) The shape stabilizer may be, for example, at least one selected from the group consisting of an amine compound, a carboxylic acid, and a phosphoric acid ester, or may be a combination of an amine compound and a carboxylic acid. The shape stabilizer coats at least a portion of the oxide-containing copper particles of the present disclosure, which makes it easier to obtain the desired light absorption characteristics of the present disclosure, and also improves the fluidity of a paste composition using the copper particles.

[0029] Examples of the amine compound include monoamines such as dipropylamine, butylamine, dibutylamine, hexylamine, cyclohexylamine, heptylamine, octylamine, nonylamine, decylamine, 3-aminopropyltriethoxysilane, dodecylamine, oleylamine, monoethanolamine, 2-aminoethoxy-2-ethanol, 3-amino-1-propanol, 3-amino-2-propanol, 4-amino-1-butanol, 3-amino-1-hexanol, and 2-(2-aminoethoxy)ethanol; ethylenediamine, N,N-dimethylethylenediamine, and the like. Examples of the amine compound include diamines such as hexane, N,N'-dimethylethylenediamine, N,N-diethylethylenediamine, N,N'-diethylethylenediamine, 1,3-propanediamine, 2,2-dimethyl-1,3-propanediamine, N,N-dimethyl-1,3-diaminopropane, N,N'-dimethyl-1,3-diaminopropane, N,N-diethyl-1,3-diaminopropane, 1,4-diaminobutane, 1,5-diamino-2-methylpentane, 1,6-diaminohexane, N,N'-dimethyl-1,6-diaminohexane, 1,7-diaminoheptane, and 1,8-diaminooctane. The amine compound may be used alone or in combination with two or more. The amine compound may be an aminoalcohol, and the molecular weight of the aminoalcohol may be 80 or more and 150 or less.

[0030] Examples of carboxylic acids include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, octylic acid, nonanoic acid, decanoic acid, oleic acid, stearic acid, and isostearic acid; and dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and diglycolic acid. The carboxylic acid may be an aromatic carboxylic acid such as benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, or gallic acid, or a hydroxy acid such as glycolic acid, lactic acid, tartronic acid, malic acid, glyceric acid, hydroxybutyric acid, tartaric acid, citric acid, or isocitric acid. One or more carboxylic acids may be used alone, or two or more may be used in combination. The carboxylic acid may be a monocarboxylic acid. The molecular weight of the monocarboxylic acid may be 80 or more and 150 or less.

[0031] The phosphate ester can remove the oxide film formed on the surface of the copper particles by heating in the atmosphere, and can improve the sinterability of the copper particles. The phosphate ester can also improve the lubricity of the copper particles in the paste composition. The phosphate ester may be added after the reduction reaction. Examples of phosphate esters include alkyl phosphates, polyoxyethylene alkyl ether phosphates, and polyoxyethylene alkyl phenyl ether phosphates. The acid value and amine value of the phosphate ester may both be 130 mgKOH / g or less, 120 mgKOH / g or less, or 110 mgKOH / g or less. The ratio of the acid value to the amine value (acid value / amine value) may be 0 to 1.5, or 0 to 1.2. The acid value is determined by a method in accordance with JIS K 0070:1992, and the amine value is determined by a method in accordance with JIS K 7237:1995.

[0032] The total amount of the shape stabilizer used may be 0.1 to 10 mol, 0.5 to 8 mol, or 1 to 5 mol, per 1 mol of the copper compound. When an amine compound and a carboxylic acid are used as the shape stabilizer, for example, the molar ratio of the amine compound to the carboxylic acid may be 1 / 5 to 5 / 1, 1 / 3 to 3 / 1, or 1 / 2 to 2 / 1.

[0033] (reducing compounds) The reducing compound is not particularly limited as long as it has the reducing power to reduce the copper compound and liberate metallic copper. Examples of the reducing compound include hydrazine derivatives. The reducing compound may be used alone or in combination of two or more. Examples of hydrazine derivatives include hydrazine monohydrate, methylhydrazine, ethylhydrazine, n-propylhydrazine, isopropylhydrazine, n-butylhydrazine, isobutylhydrazine, sec-butylhydrazine, tert-butylhydrazine, n-pentylhydrazine, isopentylhydrazine, neopentylhydrazine, tert-pentylhydrazine, n-hexylhydrazine, isohexylhydrazine, n-heptylhydrazine, n-octylhydrazine, n-nonylhydrazine, n-decylhydrazine, n-undecylhydrazine, n-dodecylhydrazine, cyclohexylhydrazine, phenylhydrazine, 4-methylphenylhydrazine, benzylhydrazine, 2-phenylethylhydrazine, 2-hydrazinoethanol, and acetohydrazine.

[0034] The amount of the reducing compound used may be 0.1 to 10 mol, 0.5 to 5 mol, or 0.8 to 3 mol, relative to 1 mol of the copper compound.

[0035] (organic solvent) The organic solvent is not particularly limited as long as it can carry out a uniform reaction without inhibiting the properties of the complex formed by mixing the copper compound, the shape stabilizer, and the reducing compound. The organic solvent may be compatible with the reducing compound. Examples of organic solvents include alcohols such as 1-propanol, 2-propanol, butanol, pentanol, hexanol, heptanol, octanol, ethylene glycol, 1,3-propanediol, 1,2-propanediol, butyl cellosolve, ethyl carbitol, and butyl carbitol; butyl carbitol acetate, ethyl carbitol acetate, and diethylene glycol diethyl ether. One type of organic solvent may be used alone, or two or more types may be used in combination.

[0036] When an organic solvent is used, the amount used may be such that the copper compound, shape stabilizer, and reducing compound can be uniformly mixed. The amount of the organic solvent used may be, for example, 0.1 to 500 times by volume the volume of the shape stabilizer.

[0037] The reduction reaction of the copper compound may be heated from the viewpoint of sufficient reaction progress. The reaction temperature may be −20 to 140° C., 25 to 120° C., or 40 to 100° C. The reaction time may be 20 to 360 minutes, 30 to 300 minutes, or 40 to 240 minutes from the viewpoint of sufficient reaction progress.

[0038] When the content of the vessel in which the reduction reaction was carried out is a liquid (liquid mixture), the solid matter may be separated, for example, by centrifugation, etc. The obtained solid matter may be washed with an organic solvent, and further, by centrifugation, etc., it may be obtained as a cake of copper particles. The washing method is not particularly limited as long as the shape stabilizer, reducing compound, etc. are sufficiently removed. The organic solvent for washing may be an alcohol. Examples of the alcohol include ethanol, 1-propanol, 2-propanol, butanol, pentanol, hexanol, heptanol, octanol, ethylene glycol, 1,3-propanediol, 1,2-propanediol, diethylene glycol, butyl cellosolve, ethyl carbitol, and butyl carbitol. The organic solvent for washing may be used alone or in combination of two or more.

[0039] [Paste composition] The paste composition of the present disclosure includes the oxide-containing plate-like copper particles of the present disclosure described above. The content of copper particles in the paste composition may be 10 to 95 mass %, 20 to 90 mass %, or 30 to 85 mass %. In the present disclosure, the nonvolatile content, which is the components excluding the organic solvent in the paste composition, is considered to be the content of copper particles.

[0040] The paste composition may be diluted with an organic solvent from the viewpoints of ease of handling during use, viscosity, and the like. Examples of organic solvents include 1-propanol, 2-propanol, ethylene glycol, 1,3-propanediol, 1,2-propanediol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 3-methyl-1,5-pentanediol, glycerin, and polyethylene glycol, from the viewpoints of dispersibility of copper particles and volatility during sintering of the paste composition. The organic solvent may be used alone, or two or more types may be used in combination. The organic solvent for dilution may be the same as the organic solvent for washing the copper particles.

[0041] The paste composition of the present disclosure may contain, in addition to copper particles, an organic solvent, and components derived from the production of the copper particles, known additives that are applied to general conductive pastes, as necessary. Examples of additives include thermosetting resins, curing accelerators, stress reducing agents such as rubber and silicone, coupling agents, antifoaming agents, surfactants, colorants such as pigments and dyes, polymerization inhibitors, antioxidants, etc. The additives may be used alone or in combination of two or more.

[0042] The paste composition of the present disclosure can be prepared by kneading a mixture of copper particles, an organic solvent, and additives used as needed using a kneading machine such as a disperse, kneader, three-roll mill, or planetary mixer, and then degassing the mixture.

[0043] A cured product of the paste composition of the present disclosure contains a sintered body of the copper particles of the present disclosure and has high thermal conductivity and excellent heat dissipation. Therefore, when the paste composition of the present disclosure is used as a bonding material for substrates of elements or heat dissipation components, the thermal conductivity of the device is improved and the ability to dissipate heat from inside the device to the outside is improved. Therefore, the use of the paste composition of the present disclosure can stabilize the operation of various products such as semiconductor devices, electrical components, and electronic components.

[0044] [Semiconductor Devices] At least a portion of the semiconductor device of the present disclosure is bonded using the paste composition of the present disclosure. For example, the semiconductor device may be one in which a semiconductor element and a substrate serving as an element support member are bonded using the paste composition. The paste composition may be used as a die bond.

[0045] By using the paste composition of the present disclosure for bonding, a bonding layer with high density and high bonding strength is formed. The bonding layer has a low rate of change in thermal resistance even when subjected to repeated temperature changes, and high bonding reliability, resulting in a semiconductor device with stable operation.

[0046] The semiconductor element may be a known semiconductor element, for example, a transistor, a diode, etc., a wide band gap semiconductor element using SiC, GaN, etc., and a light emitting element such as an LED. Examples of element support members include copper plates, silver-plated copper plates, lead frames (PPF; Pre-Plated Leadframes) plated with Ni / Pd, Ti / Pd / Au, Ni / Pd / Au, etc., glass epoxy plates, ceramic members, etc.

[0047] The bonding strength of the bonding layer formed using the paste composition for bonding depends on the purpose and object of the bonding, but from the viewpoint of sufficient bonding strength, it may be 20 MPa or more, 30 MPa or more, or 40 MPa or more. The bonding strength is a die shear strength, and specifically, it can be measured by the method described in the examples.

[0048] From the viewpoint of good bonding strength and high bonding reliability, the density of the bonding layer may be 78% or more, 80% or more, or 82% or more. The density is the proportion of the sintered body portion in the bonding layer, and specifically, can be measured by the method described in the examples.

[0049] [Electrical and electronic components] At least a portion of the electrical or electronic component of the present disclosure is bonded using the paste composition of the present disclosure. Examples of the electrical or electronic component include a heat-generating component and a heat-dissipating component bonded using the paste composition. The paste composition may be used as an adhesive for heat-dissipating components.

[0050] By using the paste composition of the present disclosure for bonding, a bonding layer with high density and high bonding strength is formed. The bonding layer has a low rate of change in thermal resistance and high bonding reliability even when subjected to repeated thermal cycles (heat cycles), resulting in high heat dissipation and reduced temperature rise in heat-generating components, resulting in an electric or electronic component with stable operation.

[0051] Examples of the heat-generating member include an optical pickup, a power transistor, etc. The heat-generating member may be the semiconductor element or a member having the semiconductor element. Examples of the heat dissipation member include a heat sink and a heat spreader. The heat generating member and the heat dissipating member may be bonded directly via the paste composition, or may be bonded indirectly via another member with high thermal conductivity sandwiched therebetween. [Example]

[0052] Next, the present disclosure will be specifically described using examples, but the present disclosure is not limited to these examples in any way.

[0053] [Production of oxide-containing copper particles] The compounds used in the production of oxide-containing copper particles in each of the Examples and Comparative Examples are as follows. <Copper compounds> FRC-D70: Cuprous oxide; Furukawa Chemicals Co., Ltd.; specific surface area 0.2 m 2 / g FRC-D30: Cuprous oxide; Furukawa Chemicals; specific surface area 0.5 m 2 / g FRC-05B: Cuprous oxide; Furukawa Chemicals Co., Ltd.; specific surface area 2.3 m 2 / g <Amine compounds> 4-Amino-1-butanol; manufactured by Tokyo Chemical Industry Co., Ltd. 2-(2-aminoethoxy)ethanol; manufactured by Tokyo Chemical Industry Co., Ltd. 6-Amino-1-hexanol; manufactured by Tokyo Chemical Industry Co., Ltd. 3-Amino-1-propanol; manufactured by Tokyo Chemical Industry Co., Ltd. n-Octylamine; manufactured by Tokyo Chemical Industry Co., Ltd. <Carboxylic acid> Hexanoic acid; manufactured by Tokyo Chemical Industry Co., Ltd. Octanoic acid; manufactured by Tokyo Chemical Industry Co., Ltd. Acetic acid; manufactured by Tokyo Chemical Industry Co., Ltd. Decanoic acid; manufactured by Tokyo Chemical Industry Co., Ltd. <Reducing compounds> Hydrazine monohydrate; manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. <Organic solvents> 1-Propanol; manufactured by Tokyo Chemical Industry Co., Ltd. Ethanol; manufactured by Tokyo Chemical Industry Co., Ltd. Diethylene glycol; manufactured by Tokyo Chemical Industry Co., Ltd.

[0054] Example 1 A 2000 mL round-bottom flask was charged with 10 mmol of cuprous oxide (FRC-D70), 20 mmol of 4-amino-1-butanol, 20 mmol of hexanoic acid, 10 mmol of hydrazine monohydrate, and 400 mL of 1-propanol. The mixture was heated in an 80°C oil bath while stirring at 250 rpm and mixed for 180 minutes. The resulting mixture was centrifuged (25°C, 10,000 rpm, 15 minutes; the same conditions apply hereafter), and the supernatant was removed. Ethanol was added to the residue, and the mixture was washed by stirring in a vacuum planetary mixer (25°C, 1,000 rpm) for 10 minutes. It was then centrifuged and the supernatant was removed. This procedure was repeated four times. Furthermore, the ethanol was replaced with diethylene glycol, and the same washing, centrifugation, and supernatant removal procedures were repeated twice to obtain a cake of oxide-containing copper particles.

[0055] (Examples 2 to 4, Comparative Examples 1 and 2) The raw material components shown in Table 1 were used, and the same operations as in Example 1 were otherwise carried out to obtain cakes of each oxide-containing copper particle.

[0056] [Measurement and evaluation of oxide-containing copper particles] The oxide-containing copper particles (cakes) produced in the examples and comparative examples were subjected to the following measurements and evaluations. The evaluation results are shown in Table 1.

[0057] (X-ray diffraction (XRD) measurement) A cake of oxide-containing copper particles was applied to a glass plate to a thickness of 200 μm, and XRD measurements were performed using an X-ray diffractometer ("SmartLab SE," manufactured by Rigaku Corporation; CuKα radiation, focusing method). The obtained XRD pattern was fitted using a split pseudo-Voigt function.

[0058] <Cu 64 Mass ratio of O and CuO> XRD pattern analysis revealed that Cu, Cu 64 Cu relative to 100% by mass of the total of O and Cu2O 64 The contents of O and CuO were determined by the reference intensity ratio (RIR) method. Specifically, the strongest lines of each component (Cu(111), Cu 64For O(044) and Cu2O(111), the respective contents were calculated using the integrated intensity obtained by subtracting the background intensity and each RIR value (Cu: 8.86, Cu 64 O: 4.89, Cu2O: 8.28).

[0059] <Crystallite size of Cu(111)> From the full width at half maximum (FWHM) of the Cu(111) peak in the XRD pattern: β, and the Bragg angle: θ (half of the diffraction angle 2θ), the crystallite size of Cu(111): C was calculated using the following Scherrer's formula. C = K·λ / (β·cosθ) In the formula, the Scherrer constant: K = 0.94, and the characteristic X-ray wavelength of the CuKα line: λ = 0.15418 [nm]. For the sample obtained by heating the cake of oxide-containing copper particles coated in a glass plate shape at 200 °C for 1 hour in a nitrogen atmosphere, XRD measurement was similarly performed to determine the crystallite size of Cu(111). [[ID=??]]Table 1 shows the crystallite size (C1) before heating (room temperature), the crystallite size (C2) after heating (200 °C), and the ratio C2 / C1 of the two. (There seems to be a typo in the original Japanese text where "表1に、加熱前(室温)の結晶子径(C1)、加熱後(200℃)の結晶子径(C2)、及び両者の比C2 / C1を示した。" is translated as "表1に、加熱前(室温)の結晶子径(C1)、加熱後(200℃)の結晶子径(C2)、及び両者の比C2 / C1を示した。" without a proper English rendering. I assume it should be something like "Table 1 shows the crystallite size (C1) before heating (room temperature), the crystallite size (C2) after heating (200 °C), and the ratio C2 / C1 of the two." But I'm following the instruction to keep the text as close to the original as possible, so this might need to be double-checked with the source.)

[0060] (Scanning Electron Microscope (SEM) Observation) The cake of oxide-containing copper particles was applied to a brass sample stage pasted with carbon tape, and dried at 90 °C for 3 hours in a nitrogen atmosphere to prepare a sample. This sample was observed with a SEM (Schottky field emission type scanning electron microscope "JSM-F100", manufactured by JEOL Ltd.; acceleration voltage 15 kV, magnification 100,000 times; the same hereinafter). The lengths of 200 particles in the SEM image were measured to determine the thickness and major diameter of the particles. In Table 1, the thickness and major diameter show the median values respectively. Also, the SEM images of the samples for Example 4 and Comparative Example 2 are shown in FIGS. 1 and 2 respectively as representative examples.

[0061] [Evaluation of Sintered Body Properties] For the sintered bodies of oxide-containing copper particles produced in the examples and comparative examples, the following measurement and evaluation were performed. These evaluation results are also shown in Table 1 together.

[0062] (Joining strength) The oxide-containing copper particles (cake) produced in the Examples and Comparative Examples were diluted with diethylene glycol to prepare a paste composition with a nonvolatile content of 80 mass %. Using the prepared paste composition, a Ti / Pd / Au-plated aluminum nitride piece (3 mm × 3 mm, 200 μm thick) was bonded to a Ni / Pd-plated copper substrate, and heated at 200°C for 60 minutes in a nitrogen atmosphere (containing 3% hydrogen by volume) to sinter the copper particles, producing a bonded test piece (test piece without sealing resin). The die shear strength (bond strength) of the bonded test pieces was measured using a bond strength tester ("4000Plus Bond Tester", manufactured by Nordon DAGE; room temperature (25°C), distance from substrate to loading jig: 0.15 mm, loading speed: 30 mm / min).

[0063] (density) The test piece without sealing resin was embedded in epoxy resin, and then cut in the thickness direction. The sample was observed under an SEM, and the area ratio of the sintered body portion in the binarized image of the cross section of the bonding layer was calculated, and this was taken as the density.

[0064] (heat cycle test) Using the paste composition, a Ti / Au-plated silicon chip (3 mm x 3 mm, 200 μm thick) was bonded to a Ni / Pd / Au-plated die pad (4 mm x 4 mm) of a QFP (Quad Flat Package) frame, and heated at 200°C for 60 minutes in a nitrogen atmosphere (containing 3% hydrogen by volume) to sinter the copper particles. This was then mold-sealed with an epoxy resin (KE-G3000D, manufactured by Kyocera Corporation) to prepare a bonded test specimen (test specimen with sealing resin). A thermal cycling test (1 cycle: -40°C to 120°C / 30 minutes, 2000 cycles) was conducted on test pieces without encapsulating resin and test pieces with encapsulating resin. The rate of change in thermal resistance of the joint before and after the test was measured using a transient thermal resistance measurement device ("Simcenter T3Ster", manufactured by Siemens). Table 1 shows this rate of change in thermal resistance. The lower the rate of change, the higher the joint reliability; a rate of change exceeding 10% indicates low joint reliability and is rated as defective.

[0065] [Table 1]

[0066] Cu 64 The content of O is Cu, Cu2O and Cu 64 The oxide-containing copper particles (Examples 1 to 4) in which the content of Cu in the oxide-containing copper particles is in the range of 2.1 to 25.0 mass% relative to the total of 100 mass% of O have a plate-like particle shape (see Figure 1). 64 The copper particles (Comparative Examples 1 and 2) having an O content outside the above range had a substantially spherical particle shape (see FIG. 2). Furthermore, the copper particles of Comparative Examples 1 and 2 had a Cu(111) crystallite diameter of more than 30.0 nm in an unheated state (room temperature), which was larger than those of Examples 1 to 4, and showed little change before and after heating at 200° C. Therefore, it is presumed that the bonding layers formed using the paste compositions of Comparative Examples 1 and 2 had low density, did not provide sufficient bonding strength, and had low bonding reliability. It was confirmed that the paste compositions of Examples 1 to 4 were capable of forming bonding layers with high density, high bonding strength, and high bonding reliability.

Claims

1. Cu, Cu ２ O and Cu ６４ Contains O, Cu ６４ The content of O is Cu, Cu ２ O and Cu ６４ The oxide-containing plate-like copper particles have a content of 2.1 to 25.0 mass% relative to 100 mass% of the total of O.

2. Cu ２ The content of O is Cu, Cu ２ O and Cu ６４ The oxide-containing plate-like copper particles according to claim 1, wherein the content of O is 5.0 mass% or less relative to 100 mass% of the total of O.

3. 2. When heated at 200 ° C. under a nitrogen atmosphere, the ratio (C2) of the crystallite diameter of Cu (111) measured by X-ray diffraction after heating to the crystallite diameter (C1) of Cu (111) measured by X-ray diffraction before heating (C2 / C1) is 2.0 or more. Oxide-containing plate-like copper particles according to claim 1.

4. The oxide-containing plate-like copper particles according to claim 3, wherein the crystallite diameter (C2) is 55.0 nm or more.

5. 2. The oxide-containing plate-like copper particles according to claim 1, wherein the thickness is 5 to 50 nm, the major axis is 30 to 300 nm, and the major axis is greater than the thickness.

6. A paste composition comprising the oxide-containing plate-like copper particles according to any one of claims 1 to 5.

7. A method for manufacturing a semiconductor device, wherein at least a portion of the bonding is performed using the paste composition according to claim 6.

8. A method for producing an electrical component, at least a part of which is joined using the paste composition according to claim 6.

9. A method for producing an electronic component, at least a part of which is joined using the paste composition according to claim 6.

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