JP6257356B2 - Conductive adhesive, semiconductor device, and method of manufacturing conductive adhesive - Google Patents

Description

  The present invention relates to a conductive adhesive, a semiconductor device including a cured product of the conductive adhesive, and a method for manufacturing the conductive adhesive.

  A conductive adhesive is used as a substitute for solder for electrically bonding components such as resistors and capacitors to a substrate. Conventionally, a conductive adhesive containing Ag powder and a thermosetting resin has been used.

  The conductive adhesive containing the Ag powder and the thermosetting resin has a problem of migration when a voltage is applied between the wirings. For the purpose of suppressing this migration, a conductive adhesive in which Ag powder is replaced with AgSn alloy powder has been studied.

  However, the conductive adhesive containing AgSn alloy powder and thermosetting resin has a new problem that the electrical resistance value is not low. In order to solve this problem, a conductive adhesive containing AgSn alloy, an additive such as hydroxyquinolines, and a conductive adhesive containing a resin are known (Patent Document 1).

  However, when a conductive adhesive containing AgSn alloy powder, 8-quinolinol which is a hydroxyquinoline, and an epoxy resin which is a thermosetting resin, a pot life of the conductive adhesive is shortened. There is. The reason why the pot life of this conductive adhesive is shortened is that 8-quinolinol has high reactivity, so 8-quinolinol and Ag of the AgSn alloy powder form a complex, and this 8-quinolinol and Sn complex. This is because the pot life of the conductive adhesive is shortened because the catalytic effect of this promotes the curing of the thermosetting resin.

JP 2006-225426 A

  An object of the present invention is to provide a conductive adhesive having a long pot life and low electrical resistance after curing. The present inventors have intensively studied, and the presence of an oxide film having a specific thickness on the surface of the AgSn alloy powder suppresses complex formation between 8-quinolinol and Sn of the AgSn alloy powder, and conductive adhesion. It has been found that the pot life of the agent can be increased and a conductive adhesive having a low electrical resistance after curing can be provided.

The present invention relates to a conductive adhesive that has solved the above problems by having the following configuration, a semiconductor device including a cured product of the conductive adhesive, and a method for manufacturing the conductive adhesive.
[1] (A) AgSn alloy powder, (B) 8-quinolinol, and (C) thermosetting whose surface oxide film thickness is 20 nm or more and 40 nm or less as measured by depth direction analysis of X-ray photoelectron spectroscopy A conductive adhesive comprising a conductive resin.
[2] The conductive adhesive according to [1], wherein the surface oxide film of the component (A) is made of Ag, Sn, and O.
[3] The conductive adhesive according to [1] or [2] above, wherein at least a part of the component (A) is scaly.
[4] The conductive adhesive according to any one of [1] to [3], further including (D) indium powder.
[5] A semiconductor device comprising a cured product of the conductive adhesive according to any one of [1] to [4].
[6] (A) AgSn alloy powder having a surface oxide film thickness measured by depth direction analysis of X-ray photoelectron spectroscopy formed by gas atomization method or water atomization method is 20 nm or more and 40 nm or less, (B) A method for producing a conductive adhesive, comprising mixing 8-quinolinol and (C) a thermosetting resin.
[7] As the component (A), the thickness of the surface oxide film measured by the depth direction analysis of the scaled X-ray photoelectron spectroscopy after being formed by the gas atomization method or the water atomization method is 20 nm or more and 40 nm or less. The method for producing a conductive adhesive according to the above [6], wherein a certain AgSn alloy powder is used.
[8] As the component (A), the thickness of the surface oxide film measured by the depth direction analysis of the X-ray photoelectron spectroscopy after being formed by the gas atomization method or the water atomization method is 20 nm or more and 40 nm or less The method for producing a conductive adhesive according to the above [6] or [7], wherein the AgSn alloy powder is used.

  According to the present invention [1], a conductive adhesive having a long pot life and low electrical resistance after curing can be provided.

  According to the present invention [5], a semiconductor device bonded with a low-resistance conductive adhesive can be provided.

  According to the present invention [6], a conductive adhesive having a long pot life and low resistance after curing can be easily produced.

It is a depth direction analysis result of the X-ray photoelectron spectroscopy of AgSn alloy powder ³⁾ used in the examples. (A) It is a figure which shows the change of a connection resistance value when content of a component is changed. It is a figure which shows the change of a connection resistance value when changing content of (B) component. It is a figure which shows the change of adhesive strength when content of (B) component is changed. It is a figure which shows the relationship between the processing time when an AgSn alloy powder is oxidized, and the thickness of an oxide film.

[Conductive adhesive]
The conductive adhesive of the present invention comprises (A) an AgSn alloy powder having a surface oxide film thickness of 20 nm or more and 40 nm or less as measured by depth direction analysis of X-ray photoelectron spectroscopy, (B) 8-quinolinol, And (C) a thermosetting resin.

(A) As for AgSn alloy powder, the thickness of the surface oxide film measured by the depth direction analysis of X-ray photoelectron spectroscopy is 20 nm or more and 40 nm or less. If the average thickness of the oxide film of the AgSn alloy powder is less than 20 nm, the oxide film is removed during storage at a portion where the oxide film is thin, Sn reacts with 8-quinolinol to form a complex, and conductive adhesion The pot life of the agent will be shortened. On the other hand, when the average thickness of the oxide film of the AgSn alloy powder exceeds 40 nm, the storage stability at room temperature is improved and the pot life of the conductive adhesive is increased. However, the surface oxidation occurs when the conductive adhesive is heated. The film cannot be removed sufficiently, and sufficient electrical conductivity cannot be obtained for the conductive adhesive after curing. Here, for the measurement of the oxide film thickness of the AgSn alloy powder, a scanning X-ray photoelectron spectrometer (XPS, manufactured by ULBAC-PHI, apparatus name: Quantera SXM) is used, and the monochromatic Al / Kα is used as the X-ray source. Use lines. Sputtering rate of the sample, 16.52nm / min in terms of SiO _2. And the depth at which the oxygen concentration exceeds 9% is defined as the oxide film thickness from the obtained element distribution spectrum in the depth direction. This is because the film thickness of the oxide film of the AgSn alloy powder of Comparative Example 2 to be described later that can be directly observed by a focused ion beam (FIB) is 45 nm, and when the sample is measured by XPS, the oxygen when sputtering to 45 nm is observed. This is because the concentration is 9% and the oxygen concentration of 9% or less is the internal oxygen amount of the AgSn alloy powder.

  (A) AgSn alloy powder is preferable in that Ag is 60 to 70 parts by mass with respect to a total of 100 parts by mass of Ag and Sn from the viewpoint of migration resistance and connection resistance value of the conductive adhesive after curing. The average particle size of the AgSn alloy powder is preferably 1 to 20 μm and more preferably 2 to 10 μm from the viewpoint of coating workability. Here, the average particle diameter refers to a volume-based median diameter measured by a laser diffraction method.

(A) The surface oxide film of the AgSn alloy powder is preferably composed of Ag, Sn, and O. FIG. 1 shows the results of depth direction analysis of the X-ray photoelectron spectroscopy of AgSn alloy powder ³⁾ used in Examples described later. In FIG. 1, Ag, Sn, and O are present in the range where the oxygen concentration exceeds 9% and the sputtering time is 0 to 1.3 minutes, and this range is the surface oxide film.

  (A) The AgSn alloy powder is preferably at least partially scaly from the viewpoint of thixotropy when the conductive adhesive is applied with a dispenser. (A) A component may be used independently and may be used together 2 or more types.

  (B) 8-Quinolinol removes the oxide film of the Sn-plated electrode on the surface of the AgSn alloy powder and the adherend, and decreases the connection resistance value between the cured conductive adhesive and the Sn-plated electrode. However, since 8-quinolinol has high reactivity, it forms a complex with Sn of the (A) AgSn alloy powder, and the catalytic effect of this Sn complex promotes the curing of the thermosetting resin (epoxy resin or the like). . In this invention, since the surface of (A) AgSn alloy powder is oxidized, formation of Sn complex can be suppressed. As a result, the pot life of the conductive adhesive can be lengthened.

  (C) As the thermosetting resin, for example, an epoxy resin is preferably used. The epoxy resin is not particularly limited as long as it is an epoxy compound that has two or more epoxy groups in one molecule and is cured and becomes resinous. Epoxy resins include bisphenol A type epoxy resins, brominated bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, trifunctional epoxy resins, novolac type epoxy resins, alicyclic epoxy resins, and naphthalene type epoxy resins. , Ether-based or polyether-based epoxy resins, oxirane ring-containing polybutadiene, silicone epoxy copolymer resins, and the like. Moreover, these resin may be used independently and may be used together 2 or more types.

  As a curing agent when an epoxy resin is used as the thermosetting resin, a phenol resin, an acid anhydride, an amine compound, or the like can be used.

  Examples of the phenol resin include phenol novolac resin, cresol novolac resin, naphthol modified phenol resin, dicyclopentadiene modified phenol resin, p-xylene modified phenol resin, dicyclopentadiene modified phenol resin, p-xylene modified phenol resin and the like. However, the present invention is not limited to these, and any material that is usually used for conductive adhesives may be used. Epoxy groups in the epoxy resin: The OH equivalent in the phenol resin is preferably 0.1 to 1.0 equivalent, more preferably 0.2 to 0.6 equivalent, per equivalent.

  Examples of acid anhydrides include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, alkylated tetrahydrophthalic anhydride, hexahedrophthalic anhydride, methyl hymic anhydride, dodecenyl succinic anhydride, methyl nadic anhydride However, it is not limited to these. As for the compounding ratio of the epoxy resin and the acid anhydride, the equivalent of the acid anhydride is preferably 0.1 to 1.0 equivalent per 1 equivalent of epoxy group in the epoxy resin.

  Examples of amine compounds include, but are not limited to, aliphatic polyamines, aromatic amines, and modified polyamines such as polyaminoamides, polyaminoimides, polyaminoesters, and polyaminoureas. The blending ratio of the epoxy resin and the amine compound is preferably such that the equivalent of the amine compound is 0.1 to 1.0 equivalent per epoxy group in the epoxy resin: 0.2 to 0.7 equivalent. More preferably. Furthermore, tertiary amine, imidazole, hydrazide, dicyandiamide, and melamine compounds can be used. Moreover, these hardening | curing agents may be used independently and may be used together 2 or more types.

  When the thermosetting resin further contains a curing catalyst, it is preferable from the viewpoint of the curing rate of the conductive adhesive. Examples of the curable catalyst include tertiary amine-based, imidazole-based, hydrazide-based, and dicyandiamide-based catalysts. Moreover, a curing catalyst may be used independently and may be used together 2 or more types.

  (A) A component is preferable in it being 75-88 mass parts with respect to 100 mass parts of conductive adhesives. FIG. 2 shows a change in connection resistance value when the content of the component (A) is changed. In FIG. 2, the component (B) is 2.70% by mass with respect to 100% by mass of the composition obtained by removing the reactive diluent from the conductive adhesive, and the component (A) is the thickness of the surface oxide film. 21.5 nm AgSn alloy powder (Ag: 65 mass%, Sn: 35 mass%) was adjusted to the mass% shown in FIG. As a specific composition, the case where the AgSn alloy powder of FIG. 2 is about 83% by mass (third plot from the left in FIG. 2) is Example 2 described later. When (A) AgSn alloy powder of FIG. 2 is other than about 83 mass%, (A) AgSn alloy powder is mass% shown in FIG. 2, and components other than (A) component are (B ) Component, (C) component, (D) component, and the content in an electrically conductive adhesive were changed, keeping the ratio of an additive. A method for measuring the connection resistance value will be described later. As can be seen from FIG. 2, there is no significant change in the connection resistance value depending on the content of the component (A). This is because (B) component 8-quinolinol, which is a reducing agent, exhibits a reducing effect on the Sn-plated electrode of the adherend, and at the same time, also exhibits a reducing effect on the (A) component AgSn alloy powder. Therefore, if the amount of AgSn alloy powder is increased, the advantages and disadvantages due to the change in the powder content are offset, for example, because the reduction effect per unit area on the adherend part is reduced. Conceivable.

  (B) A component is preferable in it being 1.5-3.9 mass parts with respect to 100 mass parts of conductive adhesives, and it is more preferable in it being 2.0-3.0 mass parts. If the amount is less than 1.5 parts by mass, the oxide film of the AgSn alloy powder cannot be sufficiently removed, and the connection resistance value of the conductive adhesive after curing may increase. If the amount exceeds 3.9 parts by mass Since the concentration of the resin contained in the conductive adhesive decreases, the hardness of the conductive adhesive after curing may be insufficient, and the component (B) is volatilized in the curing process of the conductive adhesive. Therefore, voids may occur. FIG. 3 shows a change in the connection resistance value when the content of the component (B) is changed. In FIG. 3, AgSn alloy powder (Ag: 65 mass) having a surface oxide film thickness of 21.5 nm as component (A) with respect to 100 mass% of the composition obtained by removing the reactive diluent from the conductive adhesive. %, Sn: 35 mass%) was 83 mass%, and the component (B) was mass% shown in FIG. The specific composition is Example 2 described later when (B) 8-quinolinol in FIG. 3 is 2.7 mass% (the fourth plot from the left in FIG. 3). When (B) 8-quinolinol in FIG. 3 is other than 2.7 mass%, (B) 8-quinolinol is changed to mass% shown in FIG. 3, and components other than the component (B) are The content in the conductive adhesive was changed while maintaining the proportions of component A), component (C), component (D) and additives. As can be seen from FIG. 3, when 8-quinolinol as the component (B) increases, the connection resistance value decreases. Since the connection resistance value is preferably 25 mΩ or less, the component (B) 8-quinolinol in FIG. 3 is preferably 1.5% by mass or more from the viewpoint of connection resistance value. In FIG. 3, 8-quinolinol as component (B) has a low connection resistance value of 21 mΩ at 1.5 mass%. Next, FIG. 4 shows a change in adhesive strength when the content of the component (B) is changed. In FIG. 4, the AgSn alloy powder (Ag: 65 mass%) whose surface oxide film thickness is 21.5 nm as component (A) with respect to 100 mass% of the composition obtained by removing the reactive diluent from the conductive adhesive. , Sn: 35 mass%) was 83 mass%, and the component (B) was mass% shown in FIG. Similar to FIG. 3, the specific composition is Example 2 described later when (B) 8-quinolinol in FIG. 4 is 2.7 mass% (the fourth plot from the left in FIG. 4). . When (B) 8-quinolinol in FIG. 4 is other than 2.7 mass%, (B) 8-quinolinol is changed to mass% shown in FIG. 4, and components other than the component (B) are ( The content in the conductive adhesive was changed while maintaining the proportions of component A), component (C), component (D) and additives. In FIG. 4, when 8-quinolinol of the component (B) is 1.5% by mass, the adhesion hardness is 25N; when 3% by mass, the adhesion hardness is 17N; when 3.6% by mass, the adhesion hardness is 13N. When 3.9% by mass, the adhesion hardness is 11N; when 4.5% by mass, the adhesion hardness is 8N. A method for measuring the adhesive strength will be described later. Since the adhesive strength is preferably 10 N or more, FIG. 4 shows that 8-quinolinol of the component (B) is preferably 3.9% by mass or less.

  The conductive adhesive preferably further contains (D) indium powder. Since the component (D) melts when the conductive adhesive is cured, the electrical resistance of the cured conductive adhesive can be stabilized. The average particle diameter of the component (D) is preferably 45 μm or less from the viewpoint of coating workability.

  The component (D) is preferably 2 to 8 parts by mass, more preferably 3 to 5 parts by mass with respect to 100 parts by mass of the conductive adhesive.

  The conductive adhesive is within the range that does not impair the purpose of the present invention, and if necessary, finely divided silica for the purpose of improving workability, a dispersant, an elastomer such as acrylonitrile rubber for the purpose of imparting flexibility, and imparting adhesion. A silane coupling agent for the purpose of, a reactive diluent for the purpose of reducing the viscosity, and the like can be contained.

  The conductive adhesive of the present invention is very useful because it can be suitably used in various fields such as dispensing and screen printing.

[Semiconductor device]
The semiconductor device of this invention contains the hardened | cured material of the said conductive adhesive. Since the conductive adhesive has a longer pot life than conventional products, the workability in the bonding process between the component and the substrate is stabilized. In addition, it is possible to extend the working time of the component and substrate bonding process. That is, the pot life of the conductive adhesive is extended and the number of times the conductive adhesive is replaced with a syringe can be reduced, so that productivity is improved. Examples of the electrode of the part to be adhered and the substrate include a Sn plating electrode, a Ni plating electrode, and a noble metal electrode. Examples of components include resistors, capacitors, and IC chips.

[Method for producing conductive adhesive]
In the method for producing a conductive adhesive of the present invention, (A) the thickness of the surface oxide film measured by the depth direction analysis of X-ray photoelectron spectroscopy formed by gas atomization method or water atomization method is 20 nm or more and 40 nm or less. The AgSn alloy powder, (B) 8-quinolinol, and (C) a thermosetting resin are mixed.

  (A) AgSn alloy powder having a surface oxide film thickness of 20 nm or more and 40 nm or less can be formed by a gas atomization method or a water atomization method. Examples of the gas used in the gas atomization method include argon gas and nitrogen gas. The AgSn alloy powder formed by the gas atomization method is spherical, and the AgSn alloy powder formed by the water atomization method is indefinite.

  The AgSn alloy powder formed by the gas atomization method can be oxidized to form a surface oxide film having a thickness of 20 nm or more and 40 nm or less. An example of the conditions for the oxidation treatment is temperature: 85 ° C., humidity: 85% RH, and the treatment time and oxide film when the AgSn alloy powder (Ag: 65 mass%, Sn: 35 mass%) is oxidized under these conditions. FIG. 5 shows the relationship with the thickness. FIG. 5 shows the thickness of the oxide film when the oxidation treatment of the AgSn alloy powder formed by the gas atomization method is 0, 2, 48, and 96 hours. The thickness of the oxide film at each treatment time is 8 3, 33.0, 38.0, 44.6 nm. Here, the thickness of the oxide film when the oxidation treatment time is 0 hour: 8.3 nm is considered to be the thickness of the natural oxide film. FIG. 5 shows the thickness of the oxide film of the AgSn alloy powder formed by the water atomization method. The thickness of the oxide film of the AgSn alloy powder formed by the water atomization method is 21.5 nm. there were. Therefore, although the AgSn alloy powder formed by the water atomization method can be used as it is, a surface oxide film of 20 nm or more and 40 nm or less can be formed by additional oxidation treatment depending on the case.

  The AgSn alloy powder formed by the gas atomization method or the water atomization method is preferably scaled. Examples of the method for scaling the AgSn alloy powder include a bead mill and a pot mill.

  The AgSn alloy powder formed by the gas atomization method or the water atomization method is more preferably oxidized after being scaled, from the viewpoint of the thickness of the surface oxide film.

  The conductive adhesive of the present invention can be prepared by, for example, stirring, melting, mixing, and dispersing the components (A) to (C) and other additives simultaneously or separately, with heat treatment as necessary. Can be obtained. The mixing, stirring, dispersing and the like devices are not particularly limited, and a raikai machine equipped with a stirring and heating device, a three-roll mill, a ball mill, a planetary mixer, a bead mill and the like can be used. . Moreover, you may use combining these apparatuses suitably.

  The method for applying the conductive adhesive is not particularly limited, and can be performed by methods known to those skilled in the art such as dispenser dispensing, printing, potting, spraying, spin coating and the like.

  An example of the curing conditions for the conductive adhesive is 120 to 180 ° C. and 10 to 60 minutes.

  Next, a method for measuring the connection resistance value of the conductive adhesive after curing will be described. A 3216 sized Sn-plated multilayer capacitor is used as a mounting component, an Ag-fired thick film is used as a substrate, the conductive adhesive of the present invention is joined, and the test piece is cured at 150 ° C. for 30 minutes. The produced test piece is measured by a four-terminal method (n = 16), and an average value of 10 mΩ or less is accepted.

  A method for measuring the adhesive strength (die shear strength) of the conductive adhesive after curing will be described. A test piece is obtained by bonding a 3216-size Sn-plated multilayer capacitor using an Ag fired thick film as a substrate, bonding it with the conductive adhesive of the present invention, and curing it at 150 ° C. for 30 minutes. It is the die shear strength value measured at room temperature (25 ° C.) using an Aiko Engineering strength tester (model number: Model 1605HTP) after curing.

The present invention will be described with reference to examples, but the present invention is not limited thereto. In the following examples, parts and% indicate parts by mass and mass% unless otherwise specified.
For the measurement of the oxide film thickness of the obtained AgSn alloy powder, a scanning X-ray photoelectron spectroscopic analyzer (XPS, manufactured by ULBAC-PHI, apparatus name: Quantera SXM) was used, and the monochromatic Al / Kα was used as the X-ray source. A line was used. Sputtering rate of the sample, 16.52nm / min in terms of SiO _2. And the depth at which the oxygen concentration exceeds 9% was defined as the oxide film thickness from the obtained element distribution spectrum in the depth direction. This is because the film thickness of the oxide film of the AgSn alloy powder of Comparative Example 2 that can be directly observed by FIB is 45 nm, and when the sample is measured by XPS, the oxygen concentration when sputtered to 45 nm is 9%, This is because the oxygen concentration of 9% or less is the internal oxygen amount of the AgSn alloy powder. FIG. 1 shows the results of depth direction analysis of the X-ray photoelectron spectroscopy of AgSn alloy powder ³⁾ used in the examples. In FIG. 1, Ag, Sn, and O are present in the range where the oxygen concentration exceeds 9% and the sputtering time is 0 to 1.3 minutes (corresponding to depth: 0 to 21.5 nm). This range is the surface oxide film.

[Preparation of AgSn alloy powder]
(A) AgSn alloy powder ¹⁾
An AgSn alloy powder (Ag: 65% by mass, Sn: 35% by mass, average particle size: 5 to 10 μm spherical powder) obtained by the gas atomization method was heated in an air atmosphere at a temperature of 85 ° C. and a humidity of 85% RH. Time treatment was performed to obtain an AgSn alloy powder having a surface oxide film with a thickness of 33 nm.

(A) AgSn alloy powder ²⁾
An AgSn alloy powder (Ag: 65% by mass, Sn: 35% by mass, average particle size: 5 to 10 μm spherical powder) obtained by the gas atomization method is 48 in an air atmosphere at a temperature of 85 ° C. and a humidity of 85% RH. Time treatment was performed to obtain an AgSn alloy powder having a surface oxide film with a thickness of 38 nm.

(A) AgSn alloy powder ³⁾
An AgSn alloy powder (Ag: 65% by mass, Sn: 35% by mass, average particle size: 2 to 5 μm of amorphous powder) having a surface oxide film with a thickness of 21.5 nm was obtained by a water atomization method.

(A) AgSn alloy powder ⁴⁾
A bead mill was used for AgSn alloy powder (Ag: 65% by mass, Sn: 35% by mass, average particle size: 2 to 5 μm of irregular shaped powder) having a surface oxide film with a thickness of 21.5 nm by a water atomization method. Then, scale processing was performed to obtain an AgSn alloy powder (scaled powder having an average particle diameter of 2 to 7 μm).

(A) AgSn alloy powder ⁵⁾
The AgSn alloy powder (Ag: 65 mass%, Sn: 35 mass%, average particle diameter: 5-10 micrometers spherical powder) obtained by the gas atomization method was used as it was. The thickness of the surface oxide film of the AgSn alloy powder was 8 nm.

(A) AgSn alloy powder ⁶⁾
An AgSn alloy powder (Ag: 65% by mass, Sn: 35% by mass, average particle size: 5 to 10 μm spherical powder) obtained by the gas atomization method is 96 in an air atmosphere at a temperature of 85 ° C. and a humidity of 85% RH. Time treatment was performed to obtain an AgSn alloy powder having a surface oxide film with a thickness of 45 nm.

[Preparation of conductive adhesive]
In the ratio shown in Table 1, (B) 8-quinolinol, (C) thermosetting resin, and additives are mixed and dispersed by a three roll until the large particle size becomes 10 μm or less (JIS-K5600- 2-5 was applied) to obtain a resin mixture. The prepared resin mixture, (A) AgSn alloy powder, and (D) In powder were mixed and stirred uniformly with a planetary mixer. After dispersion, the viscosity was adjusted with a reactive diluent (manufactured by Daicel, product name: Celoxide 3000) to obtain a conductive adhesive having an appropriate viscosity. The conductive adhesive was evacuated to remove bubbles inside the conductive adhesive.

[Evaluation of conductive adhesive]
The viscosity of the conductive adhesive was measured. First, the viscosity obtained when the obtained conductive adhesive was rotated at 25 ° C. and 1 rpm for 1 minute using a DV-1 type viscometer / No. 14 spindle (in Table 1, described as the viscosity at 1 rpm). Measured). Next, the viscosity when the conductive adhesive was rotated at 25 ° C. and 10 rpm for 1 minute using a DV-1 type viscometer / 14 spindle (described in Table 1 as viscosity at 10 rpm) Was measured. From the obtained (viscosity at 1 rpm) / 10 viscosity at 10 rpm, TI (thixotropic index, described as TI [1 rpm / 10 rpm] in Table 1) was obtained. TI is preferably 2 to 8. Table 1 shows these results.

The pot life of the conductive adhesive was evaluated. The conductive adhesive was allowed to stand at 25 ° C., and after 48 hours, the viscosity when rotated at 25 ° C. and 10 rpm for 1 minute was measured using a DV-1 type viscometer / No. 14 spindle. Viscosity change rate after 48 hours (unit:%, ([viscosity at 10 rpm after 48 hours] − [viscosity at 10 rpm before leaving]) / [viscosity at 10 rpm before leaving] × 100 ⁻¹ )] Asked. A viscosity change rate of less than 15% is acceptable. Table 1 shows the pot life evaluation results.

  The connection resistance value of the conductive adhesive after curing was measured. A test piece was obtained by bonding a 3216-size Sn-plated multilayer capacitor as a mounted component, using an Ag-fired thick film as a substrate, bonding with the conductive adhesive of the present invention, and curing at 150 ° C. for 30 minutes. The produced test piece was measured by a four-terminal method (n = 16), and the average value thereof was 10 mΩ or less. Table 1 shows the results of connection resistance values.

  As can be seen from Table 1, in all of Examples 1 to 6, good results were obtained in all of the viscosity, TI, pot life, and connection resistance value. Example 4 using the scale-like (A) component had a higher TI and a lower connection resistance value than Example 2 using the water atomized powder as it was. On the other hand, in Comparative Example 1 in which the thickness of the surface oxide film was 8 nm which was too thinner than the component (A) according to the present invention, the viscosity increased too much after 48 hours, and the pot life was unacceptable. On the other hand, in Comparative Example 2 where the thickness of the surface oxide film was too thick, the connection resistance value was unacceptable.

Claims (8)

  (A) AgSn alloy powder, (B) 8-quinolinol, and (C) thermosetting resin whose surface oxide film thickness is 20 nm or more and 40 nm or less as measured by depth direction analysis of X-ray photoelectron spectroscopy. A conductive adhesive, comprising:   The conductive adhesive according to claim 1, wherein the surface oxide film of component (A) is composed of Ag, Sn, and O.   The conductive adhesive according to claim 1 or 2, wherein at least a part of the component (A) is scaly.   The conductive adhesive according to claim 1, further comprising (D) indium powder.   The semiconductor device containing the hardened | cured material of the conductive adhesive of any one of Claims 1-4.   (A) AgSn alloy powder having a surface oxide film thickness measured by depth direction analysis of X-ray photoelectron spectroscopy formed by gas atomization method or water atomization method is 20 nm or more and 40 nm or less, (B) 8-quinolinol And (C) a method for producing a conductive adhesive, comprising mixing a thermosetting resin.   (A) AgSn alloy whose thickness of the surface oxide film is 20 nm or more and 40 nm or less measured by the depth direction analysis of the scaled X-ray photoelectron spectroscopy after being formed by gas atomization method or water atomization method The method for producing a conductive adhesive according to claim 6, wherein powder is used.   As the component (A), AgSn having a thickness of 20 nm or more and 40 nm or less, which is formed by gas atomization method or water atomization method, and further oxidized, is measured by depth direction analysis of X-ray photoelectron spectroscopy. The method for producing a conductive adhesive according to claim 6 or 7, wherein an alloy powder is used.