JP2015135859A - Method of manufacturing connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a connection structure which is excellent in ultrasonic transmissibility and can obtain excellent connection reliability.SOLUTION: A method of manufacturing a connection structure includes: an arrangement process for arranging a first circuit member 11 and a second circuit member 12 via an anisotropic conductive film 13; and a crimp process for obtaining a connection structure by applying an ultrasonic wave with a crimp tool 22 from above a buffer material 21 when crimping an adherend arranged in the arrangement process. The buffer material 21 is formed by dispersing particles in a resin. Specific acoustic impedance in the particles is smaller than specific acoustic impedance of the crimp tool 22 and larger than specific acoustic impedance of the adherend. Consequently, uniform pressurization can be performed without disturbing ultrasonic delivery to the anisotropic conductive film 13 and adhesion of the anisotropic conductive film 13 to the crimp tool 22 can be prevented.

Description

  The present invention relates to a method for manufacturing a connection structure that performs crimping connection using ultrasonic waves.

  2. Description of the Related Art Conventionally, a construction method that uses ultrasonic waves or uses ultrasonic waves, heat, and light irradiation in combination to perform crimping connection of electronic components or the like is known (see, for example, Patent Document 1). By applying ultrasonic waves, for example, a bond between gold in the conductive particles and gold at the junction terminal (bump) of the circuit member, a bond between gold in the conductive particles and tin at the junction terminal (bump) of the circuit member, and the like are formed. be able to.

  In addition, when connecting using an anisotropic conductive film, for example, in order to absorb and equalize the uneven distribution of pressure due to the inclination of the crimping tool, the uneven distribution of pressure due to variations in the terminal thickness of the electronic component is reduced. In order to absorb and make uniform, it is common to use a buffer material to prevent the anisotropic conductive film from adhering to the crimping tool. As the buffer material, silicone rubber, polytetrafluoroethylene, or the like, which exhibits elastic deformation or plastic deformation with respect to the pressure at the time of pressure bonding and has releasability, is used.

Silicone rubber, polytetrafluoroethylene and the like have a low specific acoustic impedance of about 3.0 × 10 ⁶ N · s / m ^3, and therefore, for example, the material of the crimping tool is a specific acoustic impedance of 46 × 10 ⁶ N · s / m / s. In the case of m ³ stainless steel (SUS), the difference in specific acoustic impedance becomes large, vibration is generated at the interface between the crimping tool and the buffer material, heat is generated, and ultrasonic energy is exhausted. Therefore, the original purpose of heating the adherend (for example, polyimide) or the anisotropic conductive adhesive itself cannot be achieved.

  In addition, if the cushioning material is not used, the adherend and the anisotropic conductive adhesive itself can generate heat, but the above-described uniformization by absorbing the uneven pressure and adhesion of the anisotropic conductive film to the crimping tool Cannot be prevented.

JP 2010-251789 A

  The present invention solves the above-described problems in the prior art, and provides a method of manufacturing a connection structure that is excellent in ultrasonic transmission and can obtain good connection reliability.

  In order to solve the above-described problem, a method for manufacturing a connection structure according to the present invention includes a disposing step of disposing a first circuit member and a second circuit member via an anisotropic conductive film, A crimping step of applying ultrasonic waves from above the cushioning material with a crimping tool to obtain a connection structure when crimping the adherend placed in the placement step, wherein the cushioning material is a particle in the resin The specific acoustic impedance of the particles is smaller than the specific acoustic impedance of the crimping tool and larger than the specific acoustic impedance of the adherend.

  In addition, the connection structure according to the present invention is obtained by a method for manufacturing a connection structure.

  In addition, the present invention provides an arrangement step in which the first circuit member and the second circuit member are arranged via an anisotropic conductive film, and when crimping the adherend arranged in the arrangement step, A buffer material used in a manufacturing method of a connection structure having a crimping step of applying ultrasonic waves from above the buffer material with a crimping tool to obtain a connection structure, wherein particles are dispersed in the resin, The specific acoustic impedance of the particles is smaller than the specific acoustic impedance of the crimping tool and larger than the specific acoustic impedance of the adherend.

  Since the present invention uses a buffer material with less attenuation of ultrasonic waves, the ultrasonic wave transmission is excellent and good connection reliability can be obtained.

It is sectional drawing which shows the crimping | compression-bonding process to which this invention was applied.

Hereinafter, embodiments of the present invention will be described in detail in the following order.
1. 1. Manufacturing method of connection structure Example

<1. Manufacturing method of connection structure>
The manufacturing method of the connection structure according to the present embodiment includes a disposing step of disposing the first circuit member and the second circuit member via an anisotropic conductive film, and a substrate disposed in the disposing step. A crimping step of applying ultrasonic waves from above the cushioning material with a crimping tool to obtain a connection structure.

[Arrangement process]
In the arrangement step, the first circuit member, the anisotropic conductive film (ACF), and the second circuit member are arranged in this order.

  There is no restriction | limiting in particular in a 1st circuit member and a 2nd circuit member, According to the objective, it can select suitably. For example, a glass substrate such as an LCD (Liquid Crystal Display) panel as the first circuit member, an FOG (Film On Glass) mounting using COF (Chip On Film) as the second circuit member, and an LCD as the first circuit member The present invention can be applied to a glass substrate such as a panel, and COG (Chip On Glass) mounting using an IC chip as a second circuit member.

  There is no restriction | limiting in particular in an anisotropic conductive film, According to the objective, it can select suitably. For example, heat curable type such as thermal cation curable type, thermal radical curable type, photo cation curable type, photo curable type such as photo radical curable type, heat / light curable anisotropic conduction that cures by either heat or light. A film can be used.

  For example, a thermal cation curable anisotropic conductive film contains a film-forming resin, a cation curable resin, a thermal cation polymerization initiator, and conductive particles. Moreover, the photocation curable anisotropic conductive film contains a film-forming resin, a cation curable resin, a photo cation polymerization initiator, and conductive particles. Further, the heat / photocation curable anisotropic conductive film contains a film-forming resin, a cation curable resin, a thermal cation polymerization initiator, and a photocation polymerization initiator. The heat / photocation curable anisotropic conductive film can be applied to both heat / light instead of using a heat cationic polymerization initiator and a photocationic polymerization initiator in combination. One kind of may be used. Further, a thermal cationic polymerization initiator and a thermal / photocationic polymerization initiator, or a photocationic polymerization initiator and a thermal / photocationic polymerization initiator may be combined.

  Further, for example, a thermal radical curable anisotropic conductive film contains a film-forming resin, a radical curable resin, a thermal radical polymerization initiator, and conductive particles. The photoradical curable anisotropic conductive film contains a film-forming resin, a radical curable resin, a photoradical polymerization initiator, and conductive particles. The heat / photo radical curable anisotropic conductive film contains a film-forming resin, a radical curable resin, a thermal radical polymerization initiator, and a photo radical polymerization initiator.

  Examples of the film forming resin include phenoxy resin, urethane resin, polyester resin, styrene isoprene resin, and nitrile butadiene resin.

  Examples of the cationic curable resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, novolac type epoxy resins, oxetane resins, alicyclic epoxy resins, and their modified epoxy resins. Or two or more of them may be used in combination.

  Examples of the thermal cationic polymerization initiator include benzylsulfonium salt, thiophenium salt, thioranium salt, benzylammonium salt, pyridinium salt, hydrazinium salt, carboxylic acid ester, sulfonic acid ester, and amine imide.

As a photocationic polymerization initiator, for example, the cation moiety is aromatic sulfonium, aromatic iodonium, aromatic diazonium, aromatic ammonium, thianthrhenium, thioxanthonium, (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -Fe cation, and the anion moiety is BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , [BX ₄ ] ⁻ (where X is at least two fluorines or trifluoro And onium salts composed of a phenyl group substituted with a methyl group.

  Examples of the radical curable resin include epoxy (meth) acrylates, urethane (meth) acrylates, (meth) acrylate oligomers, and the like. These may be used alone or in combination of two or more. May be used in combination.

  Examples of the thermal radical polymerization initiator include peroxides and azo compounds. Examples of peroxides include diacyl peroxide compounds, peroxy ester compounds, hydroperoxide compounds, peroxydicarbonate compounds, peroxyketal compounds, dialkyl peroxide compounds, and ketone peroxide compounds.

  Examples of the radical photopolymerization initiator include alkylphenone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, titanocene polymerization initiators, and oxime ester photopolymerization initiators.

  As electroconductive particle, the well-known electroconductive particle currently used in the anisotropic conductive film can be used. For example, on the surface of particles of various metals and metal alloys such as nickel, iron, copper, aluminum, tin, lead, chromium, cobalt, silver and gold, particles of metal oxide, carbon, graphite, glass, ceramic, plastic, etc. The thing which coated the metal, the thing which coat | covered the insulating thin film further on the surface of these particle | grains, etc. are mentioned. In the case where the surface of the resin particle is coated with metal, examples of the resin particle include an epoxy resin, a phenol resin, an acrylic resin, an acrylonitrile / styrene (AS) resin, a benzoguanamine resin, a divinylbenzene resin, a styrene resin, and the like. The particles can be used.

  Moreover, you may make it mix | blend suitably with pigments, such as silane coupling agents, an inorganic filler, elastomers, such as an acrylic rubber, and carbon black, as an other component in an anisotropic conductive film.

[Crimping process]
FIG. 1 is a cross-sectional view showing a crimping process to which the present invention is applied. As shown in FIG. 1, in the pressure-bonding step, when the adherend arranged with the first circuit member 11 and the second circuit member 12 interposed via the anisotropic conductive film 13 is pressure-bonded, the cushioning material 21. An ultrasonic wave is applied from above with the crimping tool 22 to obtain a connection structure.

  In the crimping step, the first circuit member 11 and the second circuit member 12 are electrically connected via the anisotropic conductive film 13, that is, the conductive particles in the anisotropic conductive film 13 are the first It will be in the state which touches the connection terminal of the circuit member 11 and the 2nd circuit member 12. FIG.

  In the crimping process, for example, the second circuit member 12 is pressed using a crimping tool 22 such as a heat tool, and the cushioning material 21 is further interposed between the crimping tool 22 and the second circuit member 12. It is performed with the intervention. By interposing the buffer material 21, it is possible to reduce pressure variation and to prevent the crimping tool 12 from becoming dirty.

  There is no restriction | limiting in particular as the crimping | compression-bonding tool 22, According to the objective, it can select suitably, You may perform a press once using the press member which is a larger area than a press target, Alternatively, pressing may be performed in several times using a pressing member having a small area.

  There is no restriction | limiting in particular as a front-end | tip shape of the crimping | compression-bonding tool 22, According to the objective, it can select suitably, For example, planar shape, curved surface shape, etc. are mentioned. In addition, when the tip shape is a curved surface shape, it is preferable to press along the curved surface shape.

  There is no restriction | limiting in particular as a frequency of the ultrasonic wave applied using the crimping | compression-bonding tool 22, Although it can select suitably according to the objective, It is preferable that it is 10kHz-100kHz, and it is more preferable that it is 20kHz-60kHz. . When the frequency is less than 10 kHz, the force for pushing the circuit member is insufficient, and connection failure may occur. When the frequency exceeds 100 kHz, the junction terminal of the circuit member may be deformed to cause short circuit or connection failure.

  There is no restriction | limiting in particular as a vibration direction of an ultrasonic wave, According to the objective, it can select suitably, For example, it is perpendicular | vertical with respect to the plane of the 1st circuit member 11 or the 2nd circuit member 12, even with a horizontal vibration. Any of vibration may be sufficient. From the viewpoint of reducing damage to the first circuit member 11 or the second circuit member 12, horizontal vibration is preferable, and from the viewpoint of preventing misalignment of fine pitch connection, vertical vibration is preferable.

  There is no restriction | limiting in particular as ultrasonic application time, Although it can select suitably according to the objective, It is preferable that it is 0.1 second-2.0 second, and it is 0.5 second-1.0 second. It is more preferable. If the ultrasonic wave application time is less than 0.1 second, the circuit member may be insufficiently pushed, and if it exceeds 2.0 seconds, the wiring of the circuit member may be deformed.

  There is no restriction | limiting in particular as an ultrasonic application means, According to the objective, it can select suitably, For example, the press member etc. which can apply the ultrasonic wave etc. which incorporated the vibrator | oscillator etc. are mentioned.

  By applying ultrasonic vibration to the anisotropic conductive film 13 using the crimping tool 22, curing of the anisotropic conductive film 13 can be promoted by frictional heat generated by the ultrasonic vibration. Specifically, the application of ultrasonic waves causes the metal to melt, for example, bonding of gold in conductive particles to gold in bonding terminals (bumps) of circuit members, bonding terminals of gold and circuit members in conductive particles (bumps) ) And a bond with tin can be formed. Thereby, the heating temperature of the crimping tool 22 can be lowered, and the thermal influence on the LCD member such as a polarizing plate can be reduced.

  In ultrasonic pressure bonding, it is important to reduce the attenuation of ultrasonic vibration and transmit it to the anisotropic conductive film 13. The crimping tool 22 is usually made of stainless steel (SUS) having a high specific acoustic impedance, and the buffer material 21 is usually made of silicon rubber, polyethylene terephthalate or the like having a low specific acoustic impedance.

Table 1 shows specific acoustic impedances of common substances. In addition, the specific acoustic impedance Z shows the resistance value with respect to sound, and is represented by the following formula.
Z = C × ρ
Z = acoustic impedance [kg / m ² · S = N · S / m ³ ]
C = Sonic velocity of matter [m / s]
ρ = material density [kg / m ³ ]

  When there is a large difference in specific acoustic impedance, such as stainless steel and silicon rubber, ultrasonic waves are reflected at the material interface. Therefore, the ultrasonic wave does not reach the anisotropic conductive film 13, and the effect of promoting the curing of the anisotropic conductive film 13 by frictional heat generated by ultrasonic vibration cannot be obtained.

  In this embodiment, the particles are dispersed in the resin of the buffer material, and the specific acoustic impedance of the particles is smaller than the specific acoustic impedance of the crimping tool and larger than the specific acoustic impedance of the adherend, so Increase the impedance and reduce the difference from the inherent acoustic impedance of the crimping tool. Thereby, reflection of a material interface can be suppressed, attenuation of ultrasonic vibration can be suppressed, and ultrasonic waves can be transmitted to the anisotropic conductive film. In addition, it is preferable that the specific acoustic impedance of the adherend is the specific acoustic impedance of the base material of the second circuit member in contact with the buffer material.

The specific acoustic impedance of the particles is preferably closer to the value of the specific acoustic impedance of the material of the crimping tool than the specific acoustic impedance of the resin of the buffer material. More specifically, the specific acoustic impedance of the particles is preferably within 10 × 10 ⁶ N · S / m ³ of the value of the specific acoustic impedance of the material of the crimping tool. Thereby, the effect which suppresses attenuation | damping of an ultrasonic wave can be enlarged.

  Further, the content of the particles in the buffer material is preferably 20% by volume or more, and more preferably 20% by volume or more and 50% by volume or less. The particle content is effective even at 1% by volume, but if it is 20% by volume or more, the effect of suppressing the attenuation of ultrasonic waves is great.

  In addition, the average particle diameter (D50) of the particles in the buffer material is preferably 50% or less, more preferably 1% or more and 30% or less of the thickness of the buffer material. If the average particle size of the particles is too small, there will be many interfaces between the resin and particles of the buffer material, resulting in energy loss. If the average particle size of the particles is too large, the buffer effect due to deformation of the buffer material will be hindered. End up.

  In this way, a buffer material in which a material having a specific acoustic impedance smaller than the material of the crimping tool and a material larger than the material of the adherend or the anisotropic conductive film is dispersed is disposed between the adherend and the crimping tool. By applying ultrasonic waves in the state and applying pressure, the attenuation of ultrasonic waves applied from the crimping tool at the buffer material interface is suppressed, and relatively large ultrasonic energy is applied to the adherend and anisotropic material. Reaches the conductive conductive film and generates heat. Therefore, good connection reliability of the connection structure can be obtained.

[Modification]
Moreover, in the above-mentioned crimping | compression-bonding process, you may use energy beam irradiation, such as a heat | fever and an ultraviolet-ray, simultaneously with ultrasonic application. In addition, when using energy rays irradiation such as ultraviolet rays together, in addition to the initiator by heat in advance to the anisotropic conductive film, an initiator that causes reaction of the binder component by energy ray irradiation is used in combination. It is necessary to keep.

  In the pressure bonding process, when irradiating energy rays, after applying ultrasonic waves, light is applied to the anisotropic conductive film while the first circuit member and the second circuit member are pressure bonded via the anisotropic conductive film. Irradiate.

  The light is not particularly limited as long as it is light that can cure the photocurable resin, and can be appropriately selected according to the purpose, but light (ultraviolet light) having a wavelength of 200 nm to 750 nm is preferable. Moreover, there is no restriction | limiting in particular as a light source which emits light, According to the objective, it can select suitably, For example, an LED light source, a UV lamp light source, etc. are mentioned.

  Moreover, as a timing of light irradiation, the first circuit member and the second circuit member are pressed through an anisotropic conductive film by pressing and ultrasonic irradiation, and then light irradiation is performed. In addition, the application of ultrasonic waves is stopped during light irradiation. This is because if an ultrasonic wave is applied in a photocured state, a crack may occur in the bonded body, resulting in a decrease in connection reliability.

  There is no restriction | limiting in particular as an irradiation direction of light irradiation, It can select suitably according to irradiation efficiency etc. For example, a perpendicular direction may be sufficient with respect to irradiation object, and it inclined with respect to the perpendicular direction It may be a direction.

  Further, after irradiating light while pressing the first circuit member and the second circuit member through the anisotropic conductive film, do not further press the second circuit member toward the first circuit member. The light irradiation may be performed for 0.5 seconds or longer. Thereby, it can harden | cure further in the state which the stress to push in reduced, and can improve connection reliability further.

  There is no restriction | limiting in particular as light irradiation time, Although it can select suitably according to the objective, 1.0 second-10.0 second is preferable, and 1.0 second-5.0 second is more preferable. If the light irradiation time is less than 1.0 seconds, it may not be sufficiently photocured. If it exceeds 10.0 seconds, the connection cannot be made for a short time and the tact time increases, resulting in high costs. May end up.

  The application of ultrasonic waves and light irradiation are preferably performed from opposite directions with respect to the anisotropic conductive film. For example, it is preferable to apply ultrasonic waves from one circuit member (electronic component or FCP) side and to perform light irradiation from the other circuit member (wiring board) side.

  By performing light irradiation from the other circuit member, the pressing member for pressing one circuit member does not block light, so that the light irradiation efficiency can be improved and photocured while pressing. Can do.

  For example, in COG mounting in which a glass wiring board and an IC chip are connected, an anisotropic conductive film is disposed on the glass wiring board, and the anisotropic conductive film is melted with ultrasonic waves from the IC chip side, thereby the IC chip. After pressing, UV irradiation is performed from the glass substrate side in a state where pressure is applied, and curing is performed, so that the connection between the glass wiring substrate and the IC chip can be performed without heating. Thereby, panel warpage due to heat shrinkage can be prevented, and the problem of display unevenness can be solved.

  Further, in FOG mounting in which the glass wiring board and the COF are connected, misalignment due to thermal expansion and contraction can be reduced by the same connection method, and a sufficient connection area can be secured and terminal short-circuit can be prevented.

Moreover, in the above-mentioned crimping | compression-bonding process, in order to accelerate | stimulate melting | fusing of an anisotropic conductive film, you may carry out mounting by applying a 60 to 100 degreeC heat supplementary.
<2. Example>

  Examples of the present invention will be described below. In the present embodiment, when the adherend disposed via the anisotropic conductive film (ACF) is pressure-bonded to the first circuit member and the second circuit member, it is super A sound wave was applied to obtain a mounted body. Then, the initial connection resistance value, the connection resistance value after the high-temperature and high-humidity test, the reaction rate of ACF, and the presence or absence of ACF adhesion to the crimping tool were evaluated. The present invention is not limited to these examples.

[Production of ACF]
50 parts of phenoxy resin (product name: YP-50, manufactured by Tohto Kasei Co., Ltd.), 45 parts of bisphenol A type epoxy resin (product name: EP-828, manufactured by Japan Epoxy Resin Co., Ltd.), cationic curing agent (product name: SI-80L) , Manufactured by Sanshin Chemical Co., Ltd.) and conductive particles (product name: AUL704, manufactured by Sekisui Chemical Co., Ltd.) are weighed and mixed at a volume ratio of 10%, applied to a PET film, and formed into a sheet having a thickness of 20 μm. ACF was prepared.

[Production of mounting body]
An ITO glass substrate for evaluation (0.7 mmt glass, 50 μmP (L / S = 1/1)) is used as the first circuit member, and COF (25 μmt polyimide, 50 μmP (for evaluation) is used as the second circuit member. L / S = 1/1), 8 μmtCu wiring (Sn plating), S′perflex substrate) was used.

  The ACF slit to 1.5 mm on the ITO glass substrate was temporarily pressure-bonded on a condition of 70 ° C.-1 MPa-1 sec with a temporary pressure bonding machine having a tool width of 1.5 mm. Next, the COF was temporarily fixed by the same temporary crimping machine under the conditions of 80 ° C.-0.5 MPa-0.5 sec, and finally ultrasonic bonding was performed under the conditions of vibration 50 Hz, amplitude 2 μm, 5 MPa, 4 sec. A mounting body was produced.

The crimping tool used for ultrasonic application crimping is made of stainless steel, and its specific acoustic impedance is 46 × 10 ⁶ N · s / m ³ . The intrinsic acoustic impedance of COF polyimide is 3.5 × 10 ⁶ N · s / m ³ .

[Measurement of connection resistance]
With respect to the mounting body, an initial connection resistance and a connection resistance after a TH test (Thermal Humidity Test) at a temperature of 85 ° C. and a humidity of 85% RH for 500 hours were measured. The connection resistance was measured by using a digital multimeter (digital multimeter 7555, manufactured by Yokogawa Electric Corporation) with a 4-terminal method to flow a current of 1 mA, and a Max value, a Min value, and a Max value−Min value were obtained. .

[Calculation of reaction rate]
The following samples 1 to 3 were measured, and the reaction rate was calculated.
Sample 1: Sample of uncured anisotropic conductive film (before reaction) Sample 2: Sample obtained by completely curing sample 1 at 180 ° C. for 1 hour Sample 3: Anisotropic conductive film of mounted body (after curing) Sample of

For each sample, FT-IR measurement was performed, and from the obtained IR chart, (I) 914 cm ⁻¹ : inverse target stretching vibration of epoxy ring and (II) 829 cm ⁻¹ : C-H interfacial deflection angle of aromatic ring. Two peaks of vibration were quantified. And about each sample, the light absorbency ratio was calculated | required by the following (1) formula, and the reaction rate shown by the following (2) formula was computed using the obtained light absorbency ratio.
Absorbance ratio = (I) / (II) (1)
Reaction rate (%) = (1-absorbance ratio of sample 3 / absorbance ratio of sample 1) / (1-absorbance ratio of sample 2 / absorbance ratio of sample 1) × 100 (2)

[ACF presence or absence]
The above-mentioned mounting body was pressure-bonded 5 times, and the adhesion of ACF to the pressure-bonding tool was visually confirmed. The case where there was one or more ACF attachments was “present”, and the case where there was zero ACF attachment was “no”.

<Comparative Example 1>
In the production of the mounting body described above, ultrasonic application pressure bonding was performed without using a buffer material, and a mounting body A was obtained.

  As shown in Table 2, the Max value, the Min value, and the Max value−Min value of the initial connection resistance of the mounting body A were 3.2Ω, 1.0Ω, and 1.5Ω, respectively. Further, the Max value, the Min value, and the Max value−Min value of the connection resistance after the TH test of the mounting body A were 6.2Ω, 1.2Ω, and 5.0Ω, respectively. Moreover, the reaction rate of the anisotropic conductive film of the mounting body A was 95%. Further, when the mounting body A was produced, it was confirmed that the ACF adhered to the crimping tool.

<Comparative Example 2>
In manufacturing the mounting body described above, ultrasonic bonding was performed using the buffer material B to obtain the mounting body B. Uncured liquid silicone rubber was sandwiched between tetrafluoroethylene resin sheets and molded to a thickness of 300 μm. Thereafter, it was cured at a temperature of 60 ° C. for 24 hours. After curing, it was cut into a length of 2 cm × 10 cm to prepare a buffer material B. The intrinsic acoustic impedance of the silicone rubber is 3.0 × 10 ⁶ N · s / m ³ .

  As shown in Table 2, the Max value, the Min value, and the Max value−Min value of the initial connection resistance of the mounting body B were 5.5Ω, 5.2Ω, and 0.3Ω, respectively. Further, the Max value, the Min value, and the Max value−Min value of the connection resistance after the TH test of the mounting body B were 10.6Ω, 6.2Ω, and 4.4Ω, respectively. Moreover, the reaction rate of the anisotropic conductive film of the mounting body B was 55%. Further, when the mounting body B was produced, the adhesion of ACF to the crimping tool was not confirmed.

<Example 1>
In manufacturing the mounting body described above, ultrasonic bonding was performed using the buffer material C containing particles, and the mounting body C was obtained. Silica ((SiO ₂ ) Aerosil RY200, manufactured by Nippon Aerosil Co., Ltd.) having an average particle diameter (D50) of 0.012 μm is weighed and mixed with uncured liquid silicone rubber, and sandwiched between tetrafluoroethylene resin sheets. Molded to a thickness of 300 μm. Thereafter, it was cured at a temperature of 60 ° C. for 24 hours. After curing, the material was cut into a length of 2 cm × 10 cm to prepare a buffer material C. The intrinsic acoustic impedance of SiO ₂ is 3.3 × 10 ⁶ N · s / m ³ .

  As shown in Table 2, the Max value, the Min value, and the Max value−Min value of the initial connection resistance of the mounting body C were 2.2Ω, 1.0Ω, and 1.2Ω, respectively. Further, the Max value, the Min value, and the Max value−Min value of the connection resistance after the TH test of the mounting body C were 4.3Ω, 1.6Ω, and 2.7Ω, respectively. Further, the reaction rate of the anisotropic conductive film of the mounting body C was 70%. Further, when the mounting body C was produced, the adhesion of ACF to the crimping tool was not confirmed.

<Example 2>
In producing the mounting body described above, ultrasonic bonding was performed using the buffer material D containing particles, and the mounting body D was obtained. 30% by volume of fine zinc oxide ((ZnO) Sakai Chemical Industry Co., Ltd.) having an average particle diameter (D50) of 0.3 μm is weighed and mixed with uncured liquid silicone rubber, and sandwiched between tetrafluoroethylene resin sheets. It was molded to a thickness of 300 μm. Thereafter, it was cured at a temperature of 60 ° C. for 24 hours. After curing, a buffer material D was produced by cutting into 2 cm × 10 cm lengths. The specific acoustic impedance of ZnO is 36.1 × 10 ⁶ N · s / m ³ .

  As shown in Table 2, the Max value, the Min value, and the Max value−Min value of the initial connection resistance of the mounting body D were 1.2Ω, 1.0Ω, and 0.2Ω, respectively. Further, the Max value, the Min value, and the Max value−Min value of the connection resistance after the TH test of the mounting body D were 2.3Ω, 1.2Ω, and 1.1Ω, respectively. Moreover, the reaction rate of the anisotropic conductive film of the mounting body D was 83%. In addition, when the mounting body D was produced, the adhesion of ACF to the crimping tool was not confirmed.

<Example 3>
In producing the mounting body described above, ultrasonic application pressure bonding was performed using the buffer material E containing particles, and the mounting body E was obtained. Magnesium powder ((Mg) manufactured by Kanto Metal Co., Ltd.) having an average particle diameter (D50) of 150 μm is weighed and mixed with uncured liquid silicone rubber, and sandwiched between tetrafluoroethylene resin sheets to a thickness of 300 μm. Molded as follows. Thereafter, it was cured at a temperature of 60 ° C. for 24 hours. After curing, it was cut into a length of 2 cm × 10 cm to produce a buffer material E. The specific acoustic impedance of Mg is 10.0 × 10 ⁶ N · s / m ³ .

  As shown in Table 2, the Max value, the Min value, and the Max value−Min value of the initial connection resistance of the mounting body E were 2.4Ω, 1.2Ω, and 1.2Ω, respectively. Further, the Max value, the Min value, and the Max value−Min value of the connection resistance after the TH test of the mounting body E were 3.1Ω, 1.8Ω, and 1.3Ω, respectively. Moreover, the reaction rate of the anisotropic conductive film of the mounting body E was 73%. Further, when the mounting body E was produced, the adhesion of ACF to the crimping tool was not confirmed.

<Example 4>
In manufacturing the mounting body described above, ultrasonic bonding was performed using the buffer material F containing particles, and the mounting body F was obtained. Nickel metal particles (Ni) having an average particle size (D50) of 6 μm were weighed and mixed in uncured liquid silicone rubber, sandwiched between tetrafluoroethylene resin sheets, and molded to a thickness of 300 μm. Thereafter, it was cured at a temperature of 60 ° C. for 24 hours. After curing, the material was cut into a length of 2 cm × 10 cm to prepare a buffer material F. The specific acoustic impedance of Ni is 42.2 × 10 ⁶ N · s / m ³ .

  As shown in Table 2, the Max value, the Min value, and the Max value−Min value of the initial connection resistance of the mounting body F were 2.3Ω, 1.2Ω, and 1.1Ω, respectively. Further, the Max value, the Min value, and the Max value−Min value of the connection resistance after the TH test of the mounting body F were 2.9Ω, 1.4Ω, and 1.5Ω, respectively. Moreover, the reaction rate of the anisotropic conductive film of the mounting body F was 80%. In addition, when the mounting body F was produced, ACF adhesion to the crimping tool was not confirmed.

<Example 5>
In manufacturing the mounting body described above, ultrasonic bonding was performed using the buffer material G containing particles, and the mounting body G was obtained. Nickel metal particles (Ni) having an average particle size (D50) of 6 μm were weighed and mixed in uncured liquid silicone rubber, sandwiched between tetrafluoroethylene resin sheets, and molded to a thickness of 300 μm. Thereafter, it was cured at a temperature of 60 ° C. for 24 hours. After curing, the material was cut into a length of 2 cm × 10 cm to prepare a buffer material G. The specific acoustic impedance of Ni is 42.2 × 10 ⁶ N · s / m ³ .

  As shown in Table 2, the Max value, the Min value, and the Max value−Min value of the initial connection resistance of the mounting body G were 2.2Ω, 1.1Ω, and 1.1Ω, respectively. Moreover, the Max value, the Min value, and the Max value−Min value of the connection resistance after the TH test of the mounting body G were 2.8Ω, 1.3Ω, and 1.5Ω, respectively. Moreover, the reaction rate of the anisotropic conductive film of the mounting body G was 87%. In addition, when the mounting body G was manufactured, adhesion of ACF to the crimping tool was not confirmed.

<Example 6>
In manufacturing the mounting body described above, ultrasonic bonding was performed using the buffer material H containing particles, and the mounting body H was obtained. Nickel metal particles (Ni) having an average particle diameter (D50) of 20 μm were weighed and mixed with uncured liquid silicone rubber, sandwiched between tetrafluoroethylene resin sheets, and molded to a thickness of 300 μm. Thereafter, it was cured at a temperature of 60 ° C. for 24 hours. After curing, the buffer material H was cut out to a length of 2 cm × 10 cm. The specific acoustic impedance of Ni is 42.2 × 10 ⁶ N · s / m ³ .

  As shown in Table 2, the Max value, Min value, and Max value-Min value of the initial connection resistance of the mounting body H were 2.0Ω, 1.0Ω, and 1.0Ω, respectively. Further, the Max value, the Min value, and the Max value−Min value of the connection resistance after the TH test of the mounting body H were 2.6Ω, 1.2Ω, and 1.4Ω, respectively. Moreover, the reaction rate of the anisotropic conductive film of the mounting body H was 92%. In addition, when the mounting body H was manufactured, adhesion of ACF to the crimping tool was not confirmed.

  Since the comparative example 1 does not use the buffer material, it is sensitive to the balance of the crimping tool, and the difference between the Max value and the Min value of the connection resistance is large. In addition, the adhesion of ACF to the crimping tool was also observed.

  In Comparative Example 2, since the intrinsic acoustic impedance of the cushioning material is low, ultrasonic waves are reflected at the interface between the crimping tool and the cushioning material, the ultrasonic waves do not reach the ACF, and no frictional heat is generated. The connection resistance value deteriorated due to the shortage.

  On the other hand, in Examples 1-6, by using a buffer material containing particles having a specific acoustic impedance that is smaller than the specific acoustic impedance of the crimping tool and larger than the specific acoustic impedance of the adherend during ultrasonic application crimping, Uniform pressure could be applied without hindering the arrival of ultrasonic waves to the ACF, and adhesion of the ACF to the crimping tool could be prevented.

In Examples 2, 4 to 6, since the specific acoustic impedance of the particles is within 10 × 10 ⁶ N · S / m ³ of the value of the specific acoustic impedance of the material of the crimping tool, the attenuation of ultrasonic waves is suppressed. In particular, excellent connection reliability and reaction rate could be obtained.

DESCRIPTION OF SYMBOLS 11 1st circuit member, 12 2nd circuit member, 13 Anisotropic conductive film, 21 Buffer material, 22 Crimping tool

Claims (10)

An arrangement step of arranging the first circuit member and the second circuit member via an anisotropic conductive film;
When crimping the adherend placed in the placement step, it has a crimping step of applying ultrasonic waves with a crimping tool from above the cushioning material to obtain a connection structure,
The buffer material is obtained by dispersing particles in a resin.
A method for manufacturing a connection structure, wherein the specific acoustic impedance of the particles is smaller than the specific acoustic impedance of the crimping tool and larger than the specific acoustic impedance of the adherend.   The method for manufacturing a connection structure according to claim 1, wherein the specific acoustic impedance of the particles is closer to the value of the specific acoustic impedance of the material of the crimping tool than the specific acoustic impedance of the resin of the buffer material. The method for manufacturing a connection structure according to claim 2, wherein the specific acoustic impedance of the particles is within 10 × 10 ⁶ N · S / m ³ of the value of the specific acoustic impedance of the material of the crimping tool.   The method for manufacturing a connection structure according to any one of claims 1 to 3, wherein a content of particles in the buffer material is 20% by volume or more.   The method for manufacturing a connection structure according to any one of claims 1 to 3, wherein a content of the particles in the buffer material is 20% by volume or more and 50% by volume or less.   The method for manufacturing a connection structure according to any one of claims 1 to 5, wherein an average particle diameter of the particles is 50% or less of a thickness of the buffer material.   The method for manufacturing a connection structure according to any one of claims 1 to 5, wherein an average particle diameter of the particles is 1% or more and 30% or less of a thickness of the buffer material.   The method for manufacturing a connection structure according to any one of claims 1 to 7, wherein the specific acoustic impedance of the adherend is a specific acoustic impedance of a base material of a second circuit member in contact with the buffer material.   The connection structure obtained by the manufacturing method of the connection structure of any one of Claims 1 thru | or 8. An arrangement step of arranging the first circuit member and the second circuit member via an anisotropic conductive film, and a crimping tool from above the cushioning material when crimping the adherend arranged in the arrangement step A buffer material used in a method for manufacturing a connection structure, which includes applying a ultrasonic wave to obtain a connection structure;
Particles are dispersed in the resin,
A buffer material in which the specific acoustic impedance of the particles is smaller than the specific acoustic impedance of the crimping tool and larger than the specific acoustic impedance of the adherend.