JP4247800B2 - Sinterable metal particle composition having plasticity, its production method, bonding agent and bonding method - Google Patents

Description

The present invention relates to a sinterable metal particle composition having plasticity at room temperature or under heating, a production method thereof, a sheet-like bonding agent comprising the same, and the metal particle composition interposed between a plurality of metal members, and heating. The present invention relates to a method for joining metal members in which sinterable metal particles are sintered together.

Conductive paste and heat conductive paste prepared by dispersing fine particles of metal such as silver, copper and nickel in a curable resin composition are cured by heating to form a conductive film or heat conductive film. Since it is formed, the formation of conductive circuits on printed circuit boards, the formation of electrodes for various electronic components such as resistors and capacitors and various display elements, the formation of conductive films for electromagnetic wave shielding, capacitors, resistors, diodes, memories, Bonding and bonding of chip components such as arithmetic elements (CPU) to substrates, formation of solar cell electrodes, especially formation of solar cell electrodes that cannot be processed at high temperature using amorphous silicon semiconductors, multilayer ceramic capacitors, multilayer ceramic inductors, Application to the formation of external electrodes of chip-type ceramic electronic components such as multilayer ceramic actuators is known (for example, JP 003-55701).
However, since it is in the form of paste, it is not easy to obtain a predetermined shape, size, or thickness during the forming operation or the joining operation. Conductive coatings and thermal conductive coatings are composed of metal particles and a cured resin, and the cured resin is electrically insulating and has low thermal conductivity, so there is a limit to the magnitude of electrical conductivity and thermal conductivity. is there.
In recent years, due to higher performance of chip parts, the amount of heat generated from the chip parts has increased, and improvement in thermal conductivity as well as electrical conductivity is required, but there is a limit to the response.

On the other hand, as a conductive / thermal conductive paste containing no curable resin, a noble metal paste composed of noble metal (for example, silver) flakes and an organic solvent and sintered by heating, and the noble metal paste between the electronic device and the substrate Japanese Patent Publication No. 7-111981 discloses a method of fixing an electronic device to a substrate by heating and sintering. A metal paste comprising an organic solvent and at least one metal powder selected from gold (Au) powder, silver (Ag) powder or palladium (Pd) powder having an average particle diameter of 0.005 μm to 1.0 μm; And the method of heat-sintering this metal paste on a semiconductor wafer and forming a bump is disclosed by Unexamined-Japanese-Patent No. 2005-216508.

However, the above-described paste-like metal particle composition is a mixture of metal particles having a large specific gravity and a volatile dispersion medium having a small specific gravity, and there is a problem that they are easily separated due to the difference in specific gravity between them. Further, since it is in the form of a paste, there is a problem that it is not easy to obtain a predetermined shape, size and thickness at the time of application, and the shape, size and thickness are likely to change over time.

JP 2003-55701 A 7-111981 JP 2005-216508 A

As a result of diligent research to develop a sinterable metal particle composition free from the above problems, the present inventors have heated a sinterable metal particle and a dispersion medium that is solid at room temperature and melts and volatilizes when heated. In the case of a sinterable metal particle composition having plasticity obtained by mixing under a paste to cool to room temperature, the sinterable metal particles and the volatile dispersion medium are not separated and have a predetermined shape and size. The present inventors have found that the thickness can be easily taken and the shape retainability is excellent, and the present invention has been completed.
The object of the present invention is that the sinterable metal particles and the volatile dispersion medium are not separated, can easily take a predetermined shape, size, and thickness, and is excellent in shape retainability, An object of the present invention is to provide a manufacturing method thereof, a sheet-like bonding agent, and a method of strongly bonding a metal member using the same.

This purpose is
[1] (A) 100 parts by weight of sinterable metal particles having an average particle diameter of 0.001 to 50 μm, and (B) a solid state at room temperature and a temperature not higher than the sintering temperature of the metal particles (A). A sinterable metal particle composition comprising 3 to 100 parts by weight of a dispersion medium that melts and volatilizes, and has plasticity at room temperature or under heating.
[1-1] The sinterable metal particle composition according to [1], wherein the sinterable metal particles are silver particles.
[1-2] The sinterable metal particle composition according to [1] or [1-1], wherein the dispersion medium (B) is an alcohol, a hydrocarbon, a ketone or a fatty acid. .
[2] (A) 100 parts by weight of sinterable metal particles having an average particle diameter of 0.001 to 50 μm, (B) a solid state at room temperature, and a temperature below the sintering temperature of metal particles (A) The sinterability according to claim 1, wherein 3 to 100 parts by weight of the dispersion medium which is melted and volatilized is mixed at a temperature equal to or higher than the melting point of the dispersion medium (B) to form a paste and cooled to room temperature. A method for producing a metal particle composition.
[2-1] The method for producing a sinterable metal particle composition according to [2], wherein the sinterable metal particles are silver particles.
[2-2] The sinterable metal particle composition according to [2] or [2-1], wherein the dispersion medium (B) is an alcohol, a hydrocarbon, a ketone or a fatty acid. Manufacturing method.
[3] A metal member bonding agent comprising the sinterable metal particle composition according to [1] and having a sheet shape.
[3-1] The metal member bonding agent according to [3], wherein the sinterable metal particles are silver particles.
[3-2] The bonding agent for metal members according to [3] or [3-1], wherein the dispersion medium (B) is an alcohol, a hydrocarbon, a ketone or a fatty acid.
[4] The sinterable metal particle composition according to [1] or the bonding agent according to [3] is interposed between a plurality of metal members and dispersed by heating to a temperature equal to or higher than the melting point of the dispersion medium (B). The medium (B) is volatilized and the metal particles (A) are sintered together by heating, applying pressure while heating, applying pressure while applying ultrasonic vibration, or applying pressure and heating while applying ultrasonic vibration. And joining a plurality of metal members to each other.
[4-1] When the melting point of the dispersion medium (B) is 100 ° C. or lower, the metal particles (A) are sintered at 100 ° C. to 400 ° C. Member joining method.
[4-2] The method for joining metal members according to [4] or [4-1], wherein the sinterable metal particles are silver particles.
[4-3] The metal according to [4], [4-1] or [4-2], wherein the dispersion medium (B) is an alcohol, a hydrocarbon, a ketone or a fatty acid. A method for joining manufactured members.
Achieved by;

Since the sinterable metal particle composition of the present invention has plasticity at room temperature or under heating, the metal particles having a large specific gravity and the volatile dispersion medium having a small specific gravity are not separated, and can easily take a predetermined shape, Moreover, it has excellent shape retention.
Since the sheet-like bonding agent of the present invention has plasticity at normal temperature or under heating, the metal particles having a large specific gravity and the volatile dispersion medium having a small specific gravity are not separated, and is excellent in handleability.
The method for producing a sinterable metal particle composition of the present invention can efficiently and easily produce a sinterable metal particle composition having plasticity at room temperature or under heating.
Since the metal member joining method of the present invention uses a sinterable metal particle composition having plasticity at room temperature or under heating, a plurality of metal members can be joined together with high accuracy and strength.

It is a top view in the measurement of the shape retention property of the sinterable metal particle composition in an Example.

Explanation of symbols

1 Silver-plated copper plate 2 Sinterable metal particle composition

The sinterable metal particle composition of the present invention comprises (A) 100 parts by weight of sinterable metal particles having an average particle diameter of 0.001 to 50 μm, (B) a solid at room temperature, and metal particles (A And 3 to 100 parts by weight of a dispersion medium that melts and volatilizes at a temperature equal to or lower than the sintering temperature, and is solid at room temperature and has plasticity at room temperature or under heating.

The material of the sinterable metal particles (A) is solid at room temperature and sintered by heating, applying pressure while heating, applying pressure and ultrasonic vibration, or applying pressure, heating and ultrasonic vibration. Examples are gold, silver, copper, palladium, nickel, tin, aluminum, and alloys thereof. Among these, silver, copper, and nickel are preferable, and silver is particularly preferable from the viewpoints of heat sinterability, thermal conductivity, and conductivity. The silver particles may be partially or entirely silver oxide.

The surface state of the sinterable metal particles (A) is not limited, and an organic substance may be attached to the surface. If the sinterability is not hindered, the type and amount of the organic matter adhering to the surface is not limited. Examples of such organic substances include reducing agents, dispersants, stabilizers, and the like that are used when the sinterable metal particles (A) are produced, and lubricants that are used when flaked.
As the lubricant, higher fatty acids, higher fatty acid metal salts, higher fatty acid amides or higher fatty acid esters are preferable, and higher fatty acids are particularly preferable. The amount of lubricant attached varies depending on the particle size, specific surface area, shape, etc. of the sinterable metal particles (A), but is preferably 3% by weight or less of the sinterable metal particles (A), more preferably 1% by weight or less. preferable. It is because heat sinterability will fall when too much.

The average particle diameter of the sinterable metal particles (A) is 0.001 to 50 μm. This average particle diameter is an average particle diameter of primary particles obtained by a laser diffraction / scattering particle size distribution measurement method. When the average particle size exceeds 50 μm, it becomes difficult to sinter. Therefore, the one where an average particle diameter is smaller is preferable and it is preferable that it is 20 micrometers or less. When the so-called nano-size is less than 0.1 μm, the surface activity is too strong, so that the storage stability of the paste-like metal particle composition may be lowered. Therefore, it is preferable that it is 0.1 micrometer or more, and 0.1-10 micrometers is more preferable.

The shape of the sinterable metal particles (A) includes a spherical shape, a substantially spherical shape, a substantially cubic shape, a flake shape, and an indefinite shape. From the viewpoint of storage stability, a flake shape is preferable.
Particularly preferably, the silver particles produced by the reduction method are made into flakes. Many methods for producing silver particles by reduction have been proposed. A method of preparing silver oxide by adding an aqueous solution of sodium hydroxide to an aqueous solution of silver nitrate, adding an aqueous solution of a reducing agent such as formalin to this to produce silver particles, washing, filtering, drying, etc. Is common.

Flaked sinterable metal particles (A) with a lubricant attached can be produced by adding a lubricant to spherical sinterable metal particles and grinding them with a ball mill or the like. (See Japanese Patent Publication No. 40-6971, JP-A-2003-55701, [0004]).
A granular sinterable metal particle and a lubricant such as a higher fatty acid, a higher fatty acid metal salt, a higher fatty acid ester, a higher fatty acid amide, and the like are put into a rotary drum device (for example, a ball mill) together with a ceramic ball. By physically hitting the sinterable metal particles, it can be easily processed into flakes (scale-like). At this time, lipophilic organic substances such as higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, and higher fatty acid amides for improving lubricity adhere to the flaky sinterable metal particles. Examples of such higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid, and higher saturated fatty acids are preferred. Examples of such higher saturated fatty acids include lauric acid, myristic acid, palmitic acid, and stearic acid.

The flaky sinterable metal surface (A) is preferably covered more than half or all with such higher fatty acids. In this way, the sinterable metal particles (A) whose metal surface is coated with a lubricant exhibit lipophilicity and improved affinity with the dispersant (B), so that the storage of the sinterable metal particle composition Stability is further improved. However, if the adhesion amount of the lubricant is too large, the sinterability may be lowered, so that it is preferably 0.01 to 3% by weight, and more preferably 0.1 to 1% by weight. The adhesion amount of the lubricant can be measured by a usual method. For example, a method of measuring weight loss by heating above the boiling point of the lubricant in nitrogen gas, and heating the sinterable metal particles (A) in an oxygen stream to adhere to the sinterable metal particles (A). An example is a method in which carbon in the lubricant is changed to carbon dioxide, and the carbon dioxide is quantitatively analyzed by infrared absorption spectroscopy.
The sinterable metal particles (A) whose surfaces are coated with a lubricant can also be produced by a usual method. For example, it can be manufactured by immersing metal particles in a lubricant solution, taking out the metal particles and drying.

In the sinterable metal particle composition of the present invention, the dispersion medium (B) is solid at room temperature, and needs to be melted and volatilized at a temperature equal to or lower than the sintering temperature of the sinterable metal particles (A). is there. This is because the sinterable metal particle composition of the present invention does not become solid at room temperature unless the volatile dispersion medium is solid at room temperature, for example, 5 ° C. to 38 ° C. In order to be solid at normal temperature, the melting point needs to be higher than normal temperature. However, if the melting point is too close to room temperature, the shape cannot be maintained on days with high temperatures or in workplaces with high temperatures, so it is preferable that the temperature be 4 ° C. or more higher than room temperature. Specifically, the melting point is preferably 40 ° C. or higher.
However, since heat sintering is generally performed at 100 to 300 ° C., the melting point of the dispersion medium (B) is lower than the sintering temperature in this temperature range, and the boiling point thereof is lower than the sintering temperature in this temperature range. preferable. Specifically, the boiling point is preferably 60 ° C to 300 ° C. If the boiling point is less than 60 ° C, the solvent tends to volatilize during the preparation of the sinterable metal particle composition. If the boiling point is greater than 300 ° C, the dispersion medium (B) remains after sintering. Because it might be.

Examples of such a dispersion medium (B) include pyrogallol, p-methylbenzyl alcohol, o-methylbenzyl alcohol, sil-3,3,5-trimethylcyclohexanol, α-terpineol, 1,4-cyclohexanedimethanol, 1, Examples include alcohols such as 4-cyclohexanediol and pinacol, hydrocarbons such as biphenyl, naphthalene and durene, ketones such as dibenzoylmethane, chalcone and acetylcyclohexane, and fatty acids such as lauric acid and capric acid. Two or more kinds of dispersion media (B) may be used in combination, but the mixture must be solid at room temperature.

The amount of the dispersion medium (B) is 3 to 100 parts by weight per 100 parts by weight of the sinterable metal particles (A). However, since the appropriate amount varies depending on the particle size, shape, specific gravity, etc. of the sinterable metal particles (A) and the properties of the dispersion medium (B), the mixture with the sinterable metal particles (A) becomes a dispersion medium (B ) Above the melting point is sufficient to form a paste, and is sufficient to be semi-solid or solid at room temperature. The sinterable metal particle composition of the present invention is a non-metallic powder, metal compound or metal complex, in addition to the sinterable metal particles (A) and the dispersion medium (B), unless it is contrary to the object of the present invention. , Thixotropic agents, stabilizers, colorants, and other additives may be contained in small or trace amounts.

The sinterable metal particle composition of the present invention has plasticity at room temperature or under heating. Plasticity at room temperature is a property that clay minerals with moderate water content exhibit. That is, the plasticity means a property that is semi-solid at normal temperature and easily plastically deforms when stress is applied. For example, “Cube-like sinterable metal particle composition does not deform even if it is left on a flat plate. However, when a hard plate is placed on the cube and the hard plate is pressed downward, the cube has a thickness of However, even if the pressing is stopped, the thickness and area are not restored. ” Plasticity under heating is a property exhibited by thermoplastics. That is, it has the property that it is solid at normal temperature and does not deform even when stress is applied, but becomes semi-solid when it exceeds a certain temperature and easily plastically deforms when stress is applied.

The sinterable metal particle composition of the present invention is preferably in the form of a sheet (including a film) at room temperature. The size of the sheet is not limited, and the thickness of the sheet is not limited, but a uniform thickness of 50 μm to 1 mm is preferable.
The sheet form is convenient for interposing between two flat metal members. The size and shape of the sheet are preferably the size and shape of the metal member to be joined, or the size and shape that require joining.
Sheet-like sinterable metal particle composition is made of sheet-like, film-like, wire-like metal (however, the same metal as sinterable metal particles (A) or a different kind of metal is sintered) (Metal that is sometimes easy to bond) may be included.

The sinterable metal particle composition of the present invention is semi-solid or solid at room temperature, but when heated to a temperature equal to or higher than the melting point of the dispersion medium (B), the dispersion medium (B) melts and becomes a paste. It begins to evaporate. However, depending on the type of the dispersion medium (B), it starts to evaporate when the temperature is further increased. When the dispersion medium (B) is volatilized or completely volatilized, the sintering metal particles (A) sinter when the temperature exceeds the sintering temperature of the sinterable metal particles (A). Become. When the sinterable metal particles (A) are in contact with the metal member during sintering, the solid metal adheres to the metal member. At this time, the sinterable metal particles (A) and the metal member are preferably the same metal, but even if they are dissimilar metals, any metal can be used as long as it can be easily bonded during sintering.
The heating and sintering temperature of the sinterable metal particles (A) needs to be not less than the melting point of the dispersion medium (B) and not less than the temperature at which the dispersion medium (B) can be volatilized.

When the sinterable metal particle composition of the present invention is used for joining a plurality of metal members, it is interposed between the metal members and has a melting point of the dispersion medium (B) or higher, or the dispersion medium (B). It is heated above the melting point and above the temperature at which the dispersion medium (B) can be volatilized, and above the temperature at which the sinterable metal particles (A) can be sintered. Specifically, when the melting point of the dispersion medium (B) is 100 ° C. or lower, this temperature is preferably 100 ° C. or higher and 400 ° C. or lower, more preferably 150 ° C. or higher and 300 ° C. or lower. preferable.
This is because metals that sinter at less than 100 ° C. are rare, and when the temperature exceeds 400 ° C., the dispersion medium (B) evaporates suddenly, which may adversely affect the shape of the metal member.
At this time, pressure, or pressure and ultrasonic vibration may be applied to the sinterable metal particle composition. When pressure is applied, the sinterability is improved, and when pressure and ultrasonic vibration are applied, the sinterability is further improved.

The shape of the solid metal obtained by sintering the sinterable metal particle composition (A) by heating or the like of the sinterable metal particle composition of the present invention is not limited to a sheet shape, but a tape shape, a linear shape, It may be disc-shaped, block-shaped, spot-shaped, or indefinite.

When the sinterable metal particle composition of the present invention is heated, heated while applying pressure, applied ultrasonic vibration while applying pressure, or applied ultrasonic vibration while applying pressure and heated, the dispersion medium (B ) Is melted and volatilized, and the sinterable metal particles (A) are sintered, whereby a solid metal having excellent strength, electrical conductivity, and thermal conductivity is obtained. This solid metal adheres to metal parts that have been in contact, such as gold-plated substrates, silver substrates, silver-plated metal substrates, metal substrates such as copper substrates, and electrodes such as electrodes on electrically insulating substrates. It is useful for joining metal substrates, joining electronic parts having metal parts, electronic devices, electrical components, electrical devices, and the like. In particular, when the sinterable metal particles (A) are silver particles, solid silver having high strength, extremely high electric conductivity and heat conductivity is preferable. Such bonding includes bonding of chip components such as capacitors and resistors to circuit boards, bonding of semiconductor chips such as diodes, memories, and CPUs to lead frames or circuit boards, bonding of high heat generating CPU chips and cooling plates. Is exemplified.

The frequency of the ultrasonic vibration is 2 kHz or more, and preferably 10 kHz or more. Although the upper limit in particular is not restrict | limited, From the capability of an ultrasonic vibration apparatus, it is about 500 kHz. Moreover, since the amplitude of ultrasonic vibration influences sinterability, it is preferably 0.1 to 40 μm, more preferably 0.3 to 20 μm, and still more preferably 0.5 to 12 μm. In addition, it is preferable to directly press the transmitting portion of the ultrasonic vibration against the sinterable metal particle composition so that the ultrasonic vibration is reliably transmitted to the sinterable metal particle composition. Alternatively, it is preferable to press the transmitting portion of the ultrasonic vibration against the sinterable metal particle composition through a cover material made of a material that hardly absorbs the ultrasonic vibration.

The pressing pressure to the sinterable metal particle composition is preferably 0.9 kPa (0.09 gf / mm ² ) or more, more preferably 9 kPa (0.92 gf / mm ² ) or more, and further preferably 39 kPa (3. 98 gf / mm ² ) or more. The upper limit of the pressing pressure is the maximum pressure at which the members to be joined are not destroyed.

The heating temperature when sintering by applying ultrasonic vibration while applying pressure and heating should be higher than room temperature, the dispersion medium (B) can be volatilized, and the sinterable metal particles (A) can be sintered. That's fine. However, if the temperature exceeds 400 ° C., the dispersion medium (B) evaporates suddenly, which may adversely affect the shape of the solid metal. The temperature is preferably lower than the melting point of 300 ° C., more preferably 300 ° C. or less.

In the sinterable metal particle composition of the present invention, since the dispersion medium does not remain after the sinterable metal particles (A) are sintered, it is not necessary to wash the sintered product. Also good.

When the sinterable metal particle composition of the present invention is in the form of a sheet, it is preferably stored by being sandwiched between protective materials such as glass plates and plastic films. Further, for the purpose of improving storage stability, refrigeration storage may be performed, and an example of storage temperature is 10 ° C. or less.

Examples and comparative examples of the present invention will be given. In Examples and Comparative Examples, “part” means “part by weight”. The method for producing a sheet-like material of the sinterable metal particle composition, the shape retention of the sinterable metal particle composition, and the adhesive strength of the solid metal by the sinterable metal particle composition are measured by the following methods. did. Note that the temperature is 25 ° C. unless otherwise specified.

[Method for producing sheet-like material of sinterable metal particle composition]
The sinterable metal particle composition according to the present invention is sandwiched between two polytetrafluoroethylene sheets and is heated to a melting point of the dispersion medium (B) + 10 ° C. Pressure was applied so that the thickness of the product was 300 μm, and the product was cooled to below the melting point of the dispersion medium (B), taken out, cut into a predetermined size, and formed into a sheet.

[Shape retention of sinterable metal particle composition]
A sinterable silver particle composition on a silver-plated copper plate 1 having a width of 25 mm, a length of 25 mm, and a thickness of 1 mm so that the size is 10.0 mm in length × 10.0 mm in width and the thickness is 300 μm. 2 and the size of the sinterable silver particle composition after being allowed to stand at 25 ° C. for 1 hour was measured, and indicated by an average value of length and width. When the sinterable silver particle composition 2 is in the form of a paste, it is pasted using a mold and a squeegee having a size of 10.0 mm in length × 10.0 mm in width and a thickness of 300 μm. The composition was printed and coated on a silver-plated copper plate, and the size of the sinterable silver particle composition after being allowed to stand at 25 ° C. for 1 hour was measured, and indicated by an average value of length and width.

[Adhesive strength A]
A sheet-like sinterable silver particle composition having a width of 5 mm, a length of 5 mm, and a thickness of 100 μm is placed on a silver-plated copper plate having a width of 25 mm, a length of 75 mm, and a thickness of 1 mm, and a width of 5 mm × length. After mounting a silver chip having a thickness of 5 mm and a thickness of 0.5 mm, the silver chip was adhered to the silver-plated copper plate by heating at 200 ° C. for 1 hour in a forced circulation oven. When the specimen was taken out of the oven and allowed to cool, the silver particles were sintered and the copper plate and the silver chip were adhered. The test specimen for measuring the adhesive strength thus obtained is attached to a die shear strength measuring tester, and the side surface of the silver chip is pressed at a speed of 23 mm / min by the die shear tool of the die shear strength measuring tester, so that the silver tip and the silver plated copper plate are pressed. The load when the joint between them was sheared and broken was defined as the adhesive strength (unit: kgf). The adhesive strength test was performed three times, and the average value was defined as adhesive strength A.

[Adhesive strength B]
A sinterable silver particle composition 5 mm × 5 mm × 100 μm thick is placed on a silver-plated copper plate 25 mm wide × 75 mm long × 1 mm thick, and 5 mm wide × 5 mm long × thickness thereon. A 0.5 mm silver chip was mounted to make an adhesive strength measurement precursor. The adhesive strength measurement precursor is attached to an ultrasonic thermocompression bonding device, and the ultrasonic thermocompression bonding device (probe) (probe) has a frequency of ultrasonic vibration of 30 kHz, an ultrasonic vibration amplitude of 4 μm, and a pressing pressure of 100 N / cm ^2. ) Was pressed from above onto the upper part of the silver chip of the precursor for adhesive strength measurement, and crimped for 30 seconds at a temperature of 200 ° C. while applying ultrasonic vibration. When the test body was taken out of the ultrasonic thermocompression bonding apparatus and allowed to cool, the silver particles were sintered and the copper plate and the silver chip were bonded. The test specimen for measuring the adhesive strength thus obtained is attached to a die shear strength measuring tester, and the side surface of the silver chip is pressed at a speed of 23 mm / min by the die shear tool of the die shear strength measuring tester, so that the silver tip and the silver plated copper plate are pressed. The load when the joint between them was sheared and broken was defined as the adhesive strength (unit: kgf). The adhesive strength test was performed three times, and the average value was defined as adhesive strength B.

[Example 1]
In a glass container, 100 parts of flaky silver particles having an average primary particle diameter of 4 μm (measured by laser diffraction method) obtained by flaking silver particles produced by a reduction method on a commercially available container, and a dispersion medium As (B), 25 parts of durene (reagent sold by Wako Pure Chemical Industries, Ltd., melting point 80 ° C., boiling point 191 ° C.) was added and stirred well on a 90 ° C. hot plate to obtain a uniform paste. The container was removed from the hot plate and placed in an atmosphere at 25 ° C. This paste-like sinterable silver particle composition was sandwiched between two 130 μm-thick polyimide sheets and pressed to a thickness of 300 μm with a press machine heated to 90 ° C. The polyimide sheet was taken out of the press machine, cooled, and peeled off from the polyimide sheet to obtain a sheet-like composition. This sheet-like composition was made of durene in which silver particles were uniformly dispersed, was a hard solid at 25 ° C., and became a paste when heated to 90 ° C. That is, it was thermoplastic.
The shape retention of this sinterable silver particle composition and the adhesive strength of the solid metal by the sinterable silver particle composition were measured. The results are summarized in Table 1. From the above results, it can be seen that this sinterable silver particle composition has no separation of flaky silver particles and durene, has excellent shape retention, and is useful for strongly joining metal members. It was.

[Example 2]
In Example 1, a sinterable metal particle composition was used in the same manner as in Example 1 except that pinacol (reagent sold by Wako Pure Chemical Industries, Ltd., melting point 42 ° C., boiling point 175 ° C.) was used instead of durene. Was prepared. This sinterable silver particle composition is pasty at 90 ° C. The sinterable silver particle composition was sandwiched between two polyimide sheets having a thickness of 130 μm, and pressed with a press machine heated to 90 ° C. so as to have a thickness of 300 μm. The polyimide sheet was taken out of the press machine, cooled, and peeled off from the polyimide sheet to obtain a sheet-like composition. This sheet-like composition was composed of pinacol in which silver particles were uniformly dispersed, was a hard solid at 25 ° C., and became a paste when heated to 80 ° C. That is, it was thermoplastic.
The shape retention of this sinterable silver particle composition and the adhesive strength of the solid metal by the sinterable silver particle composition were measured. The results are summarized in Table 1. From the above results, it can be seen that this sinterable silver particle composition has no separation of flaky silver particles and pinacol, has excellent shape retention, and is useful for firmly joining metal members. It was.

[Example 3]
In Example 2, 22 parts of pinacol and 3 parts of benzyl alcohol (reagent sold by Wako Pure Chemical Industries, Ltd., melting point: -15 ° C, boiling point: 205 ° C) were used in place of 25 parts of pinacol. Thus, a sinterable silver particle composition was prepared. This sinterable silver particle composition is pasty at 90 ° C. The sinterable silver particle composition was sandwiched between two 130 μm-thick polyimide sheets and pressed to a thickness of 300 μm with a press machine heated to 90 ° C. The polyimide sheet was taken out of the press machine, cooled, and peeled off from the polyimide sheet to obtain a sheet-like composition. The sheet-like composition was a uniform and hard solid in which silver particles, pinacol and benzyl alcohol were well dispersed. The shape retention of this sinterable silver particle composition and the adhesive strength of the solid metal by the sinterable silver particle composition were measured. The results are summarized in Table 1. From the above results, it was found that this sinterable silver particle composition has no separation of silver particles, pinacol and benzyl alcohol, has excellent shape retention, and is useful for strongly joining metal members. It was.

[Comparative Example 1]
In Example 1, sintering was carried out in the same manner as in Example 1 except that undecane (a reagent sold by Wako Pure Chemical Industries, Ltd., melting point -26 ° C., boiling point 196 ° C.) was used instead of durene as the dispersion medium. Silver particle composition was prepared. This sinterable silver particle composition was in a paste form having fluidity even at 25 ° C., and could not be formed into a sheet. The shape retention of this sinterable silver particle composition and the adhesive strength of the solid metal by the sinterable silver particle composition were measured. The results are summarized in Table 1.

[Comparative Example 2]
Flaked silver particles (0.5% by weight of stearic acid) having an average primary particle size of 3.0 μm (measured by laser diffraction method) obtained by flaking commercially available silver particles produced by a reduction method The silver surface is coated with 100 parts of this silver particle having water repellency, and ethylene glycol as a dispersion medium (reagent sold by Wako Pure Chemical Industries, Ltd., dielectric constant 39.0, melting point −13 ° C., boiling point) A paste-like silver particle composition was prepared by adding 15 parts at 198 ° C. and mixing uniformly using a rotary kneader.
This sinterable silver particle composition was in a paste form having fluidity even at 25 ° C., and could not be formed into a sheet. The shape retention of this sinterable silver particle composition and the adhesive strength of the solid metal by the sinterable silver particle composition were measured. The results are summarized in Table 1.

Since the sinterable metal particle composition of the present invention does not separate the sinterable metal particles and the dispersion medium and has excellent shape retention, a capacitor, resistor, diode, memory, arithmetic element (CPU), etc. This is useful for accurately bonding the chip component to the substrate.

Claims (4)

(A) 100 parts by weight of sinterable metal particles having an average particle diameter of 0.001 to 50 μm, and (B) solid at normal temperature and melted and volatilized at a temperature lower than the sintering temperature of metal particles (A) A sinterable metal particle composition comprising 3 to 100 parts by weight of a dispersion medium that has a plasticity at room temperature or under heating. (A) 100 parts by weight of sinterable metal particles having an average particle diameter of 0.001 to 50 μm, and (B) solid at normal temperature and melted and volatilized at a temperature lower than the sintering temperature of metal particles (A) The sinterable metal particle composition according to claim 1, wherein 3 to 100 parts by weight of the dispersion medium to be mixed is pasted at a temperature equal to or higher than the melting point of the dispersion medium (B) and cooled to room temperature. Manufacturing method. It consists of a sinterable metal particle composition of Claim 1, and is a sheet form, The joining agent of metal members characterized by the above-mentioned. The sinterable metal particle composition according to claim 1 or the bonding agent according to claim 3 is interposed between a plurality of metal members and heated to a temperature equal to or higher than the melting point of the dispersion medium (B). ) Is volatilized, heated, pressurized and heated, pressurized and applied with ultrasonic vibration, or pressurized and heated and applied with ultrasonic vibration, and the metal particles (A) are sintered together, A method for joining metal members, comprising joining metal members together.

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