JP2013055045A - Manufacturing method of connection structure, connection structure and anisotropic conductive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a connection structure which can ensure sufficient conduction reliability even if thermal shock is given thereto, or when it is exposed to high temperature high humidity.SOLUTION: In the manufacturing method of a connection structure, an anisotropic conductive material layer is placed on the upper surface of a first connected member 2 having a plurality of first electrodes 2b on the upper surface 2a by using an anisotropic conductive material containing conductive particles 5, a second connected member 4 having a plurality of second electrodes 4b on the lower surface 4a is then laminated on the upper surface 3a of the anisotropic conductive material layer, and a cured material layer 3 is formed by curing the anisotropic conductive material layer. The height of the plurality of second electrodes 4b, the absolute value of the difference between the maximum value and the minimum value of the height of the plurality of second electrodes 4b, the average particle size of a plurality of conductive particles 5 before connection, and the average value of compression recovery rate when the plurality of conductive particles 5 are subjected to 20-50% compression deformation fall within specific ranges, respectively.

Description

  The present invention uses an anisotropic conductive material including a plurality of conductive particles to electrically connect electrodes of various connection target members such as a flexible printed circuit board, a glass substrate, a glass epoxy substrate, and a semiconductor chip. The present invention relates to a connection structure manufacturing method, a connection structure, and an anisotropic conductive material.

  Pasty or film-like anisotropic conductive materials are widely known. In the anisotropic conductive material, a plurality of conductive particles are dispersed in a binder resin.

  In order to obtain various connection structures, the anisotropic conductive material is, for example, a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)) or a connection between a semiconductor chip and a flexible printed circuit board (COF ( Chip on Film)), connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)), connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)), and the like.

  As an example of the manufacturing method of the connection structure, in Patent Document 1 below, a first circuit member having a first circuit electrode, a second circuit electrode, and a tape carrier package or a flexible printed board are used. Disclosed is a method for manufacturing a connection structure in which a second circuit member to be configured is connected by an anisotropic conductive material in a state where the first circuit electrode and the second circuit electrode are arranged to face each other. Yes.

JP 2005-235530 A

  In the manufacturing method of the conventional connection structure as described in Patent Document 1, when the electrodes in the first and second circuit members are electrically connected, the conduction reliability between the electrodes in the obtained connection structure May be low.

  Furthermore, when the obtained connection structure is subjected to a thermal shock such as a cold cycle or when the connection structure is exposed to high temperature and high humidity, sufficient connection reliability may not be ensured.

  An object of the present invention is to provide a method for manufacturing a connection structure that can provide a connection structure that can ensure sufficient conduction reliability even when subjected to a thermal shock or exposed to high temperature and high humidity. It is to be. It is another object of the present invention to provide a connection structure that can ensure sufficient conduction reliability even when subjected to a thermal shock such as a cold cycle or when exposed to high temperature and high humidity. Furthermore, an object of the present invention is to provide an anisotropic structure capable of obtaining a connection structure that can ensure sufficient conduction reliability even when subjected to a thermal shock such as a cold cycle or exposed to high temperature and high humidity. It is to provide a conductive material.

  According to a wide aspect of the present invention, the upper surface of the first connection target member having a plurality of first electrodes on the upper surface is made of an anisotropic conductive material containing a curable component and a plurality of conductive particles. A step of disposing the isotropic conductive material layer; a second connection target member having a plurality of second electrodes on the lower surface on the upper surface of the anisotropic conductive material layer; The step of laminating the second electrode to face each other, the anisotropic conductive material layer is cured to form a cured product layer, and the cured product layer is used to electrically connect the first and second connection target members. A plurality of second electrode heights of 5 μm or more and 20 μm or less, respectively, and an absolute value of a difference between a maximum value and a minimum value of the plurality of second electrode heights is 0.5 μm or more and 2 μm or less, and the plurality of conductive particles before connection included in the anisotropic conductive material The average particle diameter is 2 μm or more and 20 μm or less, and the average value of the compression recovery rate when the plurality of conductive particles before connection included in the anisotropic conductive material is 20% compressively deformed is 20% or more, 50 %, And the average value of the compression recovery rate when the plurality of conductive particles before connection contained in the anisotropic conductive material is 50% compression deformed is 5% or more and 25% or less, A method for manufacturing a connection structure is provided.

  According to a wide aspect of the present invention, a first connection target member having a plurality of first electrodes on the upper surface, a second connection target member having a plurality of second electrodes on the lower surface, and the first And a cured product layer formed by curing an anisotropic conductive material that electrically connects the second connection target members and includes a curable component and a plurality of conductive particles. The second electrode height is 5 μm or more and 20 μm or less, and the absolute value of the difference between the maximum value and the minimum value of the plurality of second electrode heights is 0.5 μm or more and 2 μm or less, An average particle diameter of the plurality of conductive particles before connection included in the anisotropic conductive material is 2 μm or more and 20 μm or less, and the plurality of conductive particles before connection included in the anisotropic conductive material is The average value of compression recovery when 20% compression deformation is 20% or more, 50% And the average value of the compression recovery rate when the plurality of conductive particles before connection included in the anisotropic conductive material is 50% compression deformed is 5% or more and 25% or less. A structure is provided.

  Furthermore, according to a wide aspect of the present invention, the first connection target member having a plurality of first electrodes on the upper surface and the second connection target member having a plurality of second electrodes on the lower surface are electrically connected. An anisotropic conductive material used for forming a cured product layer connected to the substrate, comprising a curable component and a plurality of conductive particles, wherein the plurality of second electrode heights are 5 μm or more and 20 μm, respectively. The absolute value of the difference between the maximum value and the minimum value of the plurality of second electrode heights is 0.5 μm or more and 2 μm or less, and the average particle diameter of the plurality of conductive particles is 2 μm or more, 20 μm or less, the average value of the compression recovery rate when 20% of the plurality of conductive particles are compressed and deformed is 20% or more and 50% or less, and the plurality of the conductive particles is 50% compressed and deformed. When the average value of the compression recovery rate is 5% or more and 25% or less, Isotropic conductive material is provided.

  The plurality of first electrode heights are each 0.05 μm or more and 10 μm or less, and the absolute value of the difference between the maximum value and the minimum value of the plurality of first electrode heights is 0 μm or more and 5 μm or less. It is preferable.

  The average particle diameter of the plurality of conductive particles before connection included in the anisotropic conductive material is such that the first and second connection target members connected by the cured product layer face each other. The distance between the second electrodes is preferably 1.1 times to 5 times the average distance.

  In the first and second connection target members connected by the cured product layer, the average value of the distances between the plurality of facing first and second electrodes may be 1 μm or more and 15 μm or less. preferable.

  The CV value of the particle diameter of the plurality of conductive particles before connection contained in the anisotropic conductive material is preferably 3% or more and 10% or less.

  The CV value of the distance between the plurality of facing first and second electrodes in the first and second connection target members connected by the cured product layer is 10% or more and 30% or less. It is preferable.

  In the method for manufacturing a connection structure according to the present invention, an anisotropic conductive material including a curable component and a plurality of conductive particles is formed on the upper surface of a first connection target member having a plurality of first electrodes on the upper surface. A step of disposing an anisotropic conductive material layer, and a second connection target member having a plurality of second electrodes on the lower surface on the upper surface of the anisotropic conductive material layer, and the plurality of first electrodes And a step of laminating a plurality of second electrodes facing each other, and curing the anisotropic conductive material layer to form a cured product layer, and the cured product layer forms the first and second connection objects. A plurality of second electrode heights of 5 μm or more and 20 μm or less, respectively, and a maximum value and a minimum value of the plurality of second electrode heights. The absolute value of the difference is not less than 0.5 μm and not more than 2 μm, and the difference before connection is included in the anisotropic conductive material. The average particle diameter of the conductive particles is 2 μm or more and 20 μm or less, and the average value of the compression recovery rate when the plurality of conductive particles before connection included in the anisotropic conductive material is 20% compressively deformed. 20% or more and 50% or less, and the average value of the compression recovery rate when the plurality of conductive particles before connection contained in the anisotropic conductive material is 50% compression deformed is 5% or more, Since it is 25% or less, it is possible to obtain a connection structure that can ensure sufficient conduction reliability even when a thermal shock is applied or it is exposed to high temperature and high humidity.

  The connection structure according to the present invention includes a first connection target member having a plurality of first electrodes on the upper surface, a second connection target member having a plurality of second electrodes on the lower surface, and the first and first members. And a cured product layer formed by curing an anisotropic conductive material including a curable component and a plurality of conductive particles. The second electrode height is 5 μm or more and 20 μm or less, and the absolute value of the difference between the maximum value and the minimum value of the plurality of second electrode heights is 0.5 μm or more and 2 μm or less, An average particle diameter of the plurality of conductive particles before connection included in the anisotropic conductive material is 2 μm or more and 20 μm or less, and the plurality of conductive particles before connection included in the anisotropic conductive material is The average value of compression recovery when 20% compression deformation is 20% or more, 50% And the average value of the compression recovery rate when the plurality of conductive particles before connection contained in the anisotropic conductive material is 50% compression deformed is 5% or more and 25% or less, Sufficient conduction reliability can be ensured even when a thermal shock is applied or when exposed to high temperature and high humidity.

  An anisotropic conductive material according to the present invention electrically connects a first connection target member having a plurality of first electrodes on an upper surface and a second connection target member having a plurality of second electrodes on a lower surface. An anisotropic conductive material used for forming a cured product layer connected to the substrate, comprising a curable component and a plurality of conductive particles, wherein the plurality of second electrode heights are 5 μm or more and 20 μm, respectively. The absolute value of the difference between the maximum value and the minimum value of the plurality of second electrode heights is 0.5 μm or more and 2 μm or less, and the average particle diameter of the plurality of conductive particles is 2 μm or more, 20 μm or less, the average value of the compression recovery rate when 20% of the plurality of conductive particles are compressed and deformed is 20% or more and 50% or less, and the plurality of the conductive particles is 50% compressed and deformed. Since the average value of the compression recovery rate is 5% or more and 25% or less, Or given an impact, or even or exposed to high temperature and high humidity, it is possible to obtain a connection structure capable of ensuring a sufficient conduction reliability.

FIG. 1 is a partially cutaway cross-sectional view schematically showing a connection structure obtained by a method for manufacturing a connection structure according to an embodiment of the present invention. 2A to 2C are partial cutaway cross-sectional views for explaining each step of the method for manufacturing a connection structure according to one embodiment of the present invention.

  Details of the present invention will be described below.

  In the method for manufacturing a connection structure according to the present invention, an anisotropic conductive material including a curable component and a plurality of conductive particles is formed on the upper surface of a first connection target member having a plurality of first electrodes on the upper surface. A step of disposing an anisotropic conductive material layer, and a second connection target member having a plurality of second electrodes on the lower surface on the upper surface of the anisotropic conductive material layer, and the plurality of first electrodes And a step of laminating a plurality of second electrodes facing each other, and curing the anisotropic conductive material layer to form a cured product layer, and the cured product layer forms the first and second connection objects. Electrically connecting the members.

  The connection structure according to the present invention includes a first connection target member having a plurality of first electrodes on the upper surface, a second connection target member having a plurality of second electrodes on the lower surface, and the first and first members. And a cured product layer formed by curing an anisotropic conductive material including a curable component and a plurality of conductive particles.

  An anisotropic conductive material according to the present invention electrically connects a first connection target member having a plurality of first electrodes on an upper surface and a second connection target member having a plurality of second electrodes on a lower surface. It is used to form a cured product layer connected to The anisotropic conductive material according to the present invention includes a curable component and a plurality of conductive particles.

  In the method for manufacturing a connection structure according to the present invention, the connection structure according to the present invention, and the anisotropic conductive material according to the present invention, the plurality of second electrode heights are 5 μm or more and 20 μm or less, respectively. The absolute value of the difference between the maximum value and the minimum value of the second electrode height is 0.5 μm or more and 2 μm or less. Furthermore, in the method for manufacturing a connection structure according to the present invention and the connection structure according to the present invention, the average particle diameter of the plurality of conductive particles before connection included in the anisotropic conductive material is 2 μm or more and 20 μm. It is as follows. The average particle diameter of the plurality of conductive particles contained in the anisotropic conductive material according to the present invention is 2 μm or more and 20 μm or less. In the connection structure according to the present invention and the connection structure according to the present invention, the compression recovery rate when the plurality of conductive particles before connection included in the anisotropic conductive material is 20% compressively deformed. The average value of the compression recovery rate when the plurality of conductive particles before connection contained in the anisotropic conductive material is 50% compression deformed is 5%. % Or more and 25% or less. In the anisotropic conductive material according to the present invention, the average value of the compression recovery rate when the plurality of conductive particles are 20% compressed and deformed is 20% or more and 50% or less, and the plurality of the conductive particles The average value of the compression recovery rate when the conductive particles are 50% compressed and deformed is 5% or more and 25% or less.

  The manufacturing method of the connection structure according to the present invention, the connection structure according to the present invention, and the anisotropic conductive material according to the present invention are provided with the above-described configuration, so that a thermal shock such as a cooling / heating cycle is applied. In addition, it is possible to provide a connection structure that can ensure sufficient conduction reliability even when exposed to high temperature and high humidity. Further, when the first and second electrodes are connected via the conductive particles, an indentation that is a recess formed by the conductive particles being pushed into the electrode surface can be formed on the electrode.

  Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

  In FIG. 1, the connection structure which concerns on one Embodiment of this invention is typically shown with a partial notch front sectional drawing. Moreover, the connection structure shown in FIG. 1 is also a connection structure obtained by the method for manufacturing a connection structure according to an embodiment of the present invention, and further includes an anisotropic conductive material according to the embodiment of the present invention. It is also the connection structure used.

  The connection structure 1 shown in FIG. 1 is a cured product in which the first connection target member 2, the second connection target member 4, and the first and second connection target members 2 and 4 are electrically connected. Layer 3. The cured product layer 3 is a connection part that connects the first and second connection target members 2 and 4. The cured product layer 3 is formed by curing an anisotropic conductive material including a curable component and a plurality of conductive particles 5.

  The first connection target member 2 has a plurality of first electrodes 2b on the upper surface 2a. The second connection target member 4 has a plurality of second electrodes 4b on the lower surface 4a. The first electrode 2 b and the second electrode 4 b are electrically connected by one or a plurality of conductive particles 5.

  The height of the plurality of second electrodes 4b is 5 μm or more and 20 μm or less, respectively. The height of the plurality of second electrodes 4b is preferably 10 μm or more, and preferably 15 μm or less. The absolute value of the difference between the maximum value and the minimum value of the heights of the plurality of second electrodes 4b is 0.5 μm or more and 2 μm or less. Therefore, the plurality of second electrodes 4b have height variations. For this reason, in the connection structure 1, the distance between the first and second electrodes 2 b and 4 b generally varies. In FIG. 1, two second electrodes 4b are shown, and the height of the second electrode 4b on the right side is higher than the height of the second electrode 4b on the left side. On the other hand, in FIG. 1, two first electrodes 2b are shown, and the height of the first electrode 2b on the right side and the height of the first electrode 2b on the left side are the same.

  The average particle diameter of the plurality of conductive particles 5 before connection included in the anisotropic conductive material is 2 μm or more and 20 μm or less. When the average particle diameter of the conductive particles 5 is 2 μm or more and 20 μm or less, the conductive particles 5 are separated from the first and second conductive particles 5 even if the gap distance between the first and second electrodes 2 b and 4 b varies. The electrodes 2b and 4b can be effectively brought into contact with each other, and the conduction reliability between the first and second electrodes 2b and 4b can be improved. Furthermore, sufficient conduction reliability can be ensured even when a thermal shock such as a cooling / heating cycle is given, or even when exposed to high temperature and high humidity.

  From the viewpoint of further improving the conduction reliability between the electrodes of the connection structure and further enhancing the conduction reliability when subjected to thermal shock or exposed to high temperature and high humidity, the above anisotropic conductive property is used. The average particle diameter of the plurality of conductive particles 5 before connection contained in the material is preferably 3 μm or more, more preferably 10 μm or less.

  The “average particle size” of the conductive particles indicates a number average particle size. The average particle diameter of the conductive particles is determined by observing a plurality of arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value. When measuring the average particle diameter of the conductive particles, it is preferable to observe 50 conductive particles with an electron microscope or an optical microscope and calculate the average value.

  From the viewpoint of further improving the conduction reliability of the connection structure, the height of each of the plurality of first electrodes 2b is preferably 0.05 μm or more, more preferably 0.1 μm or more, preferably 10 μm or less, more preferably 3 μm or less. From the viewpoint of further improving the conduction reliability between the electrodes of the connection structure and further improving the conduction reliability when subjected to thermal shock or exposed to high temperature and high humidity, the plurality of first The absolute value of the difference between the maximum value and the minimum value of the electrode 2b height is preferably 0 μm or more and 5 μm or less. The absolute value of the difference between the maximum value and the minimum value of the heights of the plurality of first electrodes 2b is more preferably 3 μm or less. There is no difference between the maximum value and the minimum value of the heights of the plurality of first electrodes 2b, and the plurality of first electrodes 2b may have the same height.

  The average particle diameter of the plurality of conductive particles 5 before connection included in the anisotropic conductive material is a plurality of opposing first and second connection target members 2 and 4 connected by the cured product layer 3. It is preferable that it is 1.1 times or more and 5 times or less of the average value of the gap distance between the first and second electrodes 2b and 4b. The average particle diameter of the plurality of conductive particles 5 before connection included in the anisotropic conductive material is a plurality of opposing first and second connection target members 2 and 4 connected by the cured product layer 3. The average value of the distance between the first and second electrodes 2b and 4b is preferably 1.3 times or more, and more preferably 3 times or less. When the average particle diameter of the conductive particles 5 and the average value of the distances of the gaps satisfy the above relationship, the conduction reliability between the electrodes of the connection structure is further increased and a thermal shock is applied or the temperature is high. The conduction reliability when exposed to high humidity is further increased.

  From the viewpoint of further improving the conduction reliability between the electrodes of the connection structure, a plurality of first and second opposing members in the first and second connection target members 2 and 4 connected by the cured product layer 3 are used. The average value of the distance between the electrodes 2b and 4b is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 15 μm or less, more preferably 10 μm or less, and even more preferably 4 μm or less.

  The average value of the compression recovery rate when the plurality of conductive particles 5 before connection included in the anisotropic conductive material is 20% compression deformed is 20% or more and 50% or less, and the anisotropic conductivity The average value of the compression recovery rate when the plurality of conductive particles before connection contained in the material is 50% compression deformed is 5% or more and 25% or less. When the average value of the compression recovery rate when the 20% compression deformation is performed is not less than the above lower limit and not more than the above upper limit, the contact area between the conductive particles and the electrode can be improved, and the conduction reliability of the connection structure Can be increased. When the average value of the compression recovery rate when the 50% compression deformation is performed is not less than the above lower limit and not more than the above upper limit, the cured product layer may be subjected to thermal shock or the cured product layer may be exposed to high temperature and high humidity. As a result, even if the distance between the first and second electrodes increases due to the expansion of the cured product layer, the conductive particles that are compressed return to the original shape, and as a result, the conduction reliability of the connection structure can be sufficiently secured. . Further, as shown in FIG. 1, the distance of the gap between the left and first electrodes 2b and 4b on the left side is different from the distance of the gap between the first and second electrodes 2b and 4b on the right side. The degree of compression of the conductive particles 5 arranged between the first and second electrodes 2b and 4b on the left side and the conductive particles 5 arranged between the first and second electrodes 2b and 4b on the right side are different. . Among the plurality of first and second electrodes, in a region where the gap distance is relatively small, the degree of compression of the conductive particles is large, but the compression recovery at the time of compression deformation (for example, 50% compression deformation) with a large degree of compression. Since the rate is relatively small, the repulsive force that the conductive particles compressed in the region where the gap distance is small tries to return to the original shape becomes weak, and the occurrence of peeling can be suppressed. On the other hand, among the plurality of first and second electrodes, in the region where the gap distance is relatively large, the degree of compression of the conductive particles is small, but the compression degree is small (for example, 20% compression deformation). Since the compression recovery rate is relatively large, it is possible to prevent the conductive particles from coming into contact with the first and second electrodes in a region where the gap distance is large. In addition, even if the cured product layer is subjected to thermal shock or the cured product layer is exposed to high temperature and high humidity, the cured product layer expands and the distance between the first and second electrodes increases. Since the conductive particles that have been appropriately returned to the original shape, it is possible to suppress the occurrence of poor conduction. Furthermore, when the average value of the compression recovery rate when the 20% compression deformation and the average value of the compression recovery rate when the 50% compression deformation is not less than the above lower limit and not more than the above upper limit, When connecting the 1st, 2nd electrode, the impression which is a recessed part formed when the electroconductive particle pushed in this electrode surface can also be easily formed in an electrode.

  The average value of the compression recovery rate when the plurality of conductive particles 5 before connection contained in the anisotropic conductive material is 20% compressed and deformed is preferably 25% or more, more preferably 30% or more. The average value of the compression recovery rate when the plurality of conductive particles 5 before connection contained in the anisotropic conductive material is 20% compressively deformed is preferably 25% or more, and more preferably 30% or more. More preferred. Further, particularly when the average value of the compression recovery rate when the plurality of conductive particles 5 before connection contained in the anisotropic conductive material is 50% compression deformed is 20% or more and 25% or less, The average value of the compression recovery rate when the plurality of conductive particles 5 before connection contained in the anisotropic conductive material is 20% compressively deformed is preferably 25% or more, more preferably 30% or more. preferable. The compression recovery rate when compressing and deforming the plurality of conductive particles 5 before connection included in the anisotropic conductive material by 20% is the same as that of the plurality of conductive particles 5 before connection included in the anisotropic conductive material. It is preferably equal to or higher than the compression recovery rate when 50% compression deformation occurs. The compression recovery rate when compressing and deforming the plurality of conductive particles 5 before connection included in the anisotropic conductive material by 20% is the same as that of the plurality of conductive particles 5 before connection included in the anisotropic conductive material. It is more preferably greater than the compression recovery rate when 50% compression deformed, more preferably 1% or more, and particularly preferably 5% or more.

  The compression recovery rate can be measured as follows.

  Spread conductive particles on the sample stage. With respect to one dispersed conductive particle, a load (reversal load value) is applied to the central direction of the conductive particle until the conductive particle is 20% or 50% compressively deformed using a micro compression tester. Thereafter, unloading is performed up to the origin load value (0.40 mN). The load-compression displacement during this period is measured, and the compression recovery rate can be obtained from the following equation. The load speed is 0.33 mN / sec. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

Compression recovery rate (%) = [(L1-L2) / L1] × 100
L1: Compressive displacement from the load value for the origin to the reverse load value when applying the load L2: Compressive displacement from the reverse load value to the load value for the origin when releasing the load

  From the viewpoint of further improving the conduction reliability between the electrodes of the connection structure and further enhancing the conduction reliability when subjected to thermal shock or exposed to high temperature and high humidity, the above anisotropic conductive property is used. The average value of the compression elastic modulus (20% K value) of the conductive particles 5 when the plurality of conductive particles 5 before connection contained in the material is 20% compression deformed is preferably 1 GPa or more, more preferably 2 GPa or more. , Preferably 7 GPa or less, more preferably 6 GPa or less, still more preferably 5 GPa or less.

  From the viewpoint of further improving the conduction reliability between the electrodes of the connection structure and further enhancing the conduction reliability when subjected to thermal shock or exposed to high temperature and high humidity, the above anisotropic conductive property is used. The average value of the compression elastic modulus (50% K value) of the conductive particles 5 when the plurality of conductive particles 5 before connection contained in the material is 50% compression deformed is preferably 0.5 GPa or more, more preferably 0.8 GPa or more, preferably 5 GPa or less, more preferably 4 GPa or less, and even more preferably 3 GPa or less.

  The compression elastic modulus of the conductive particles is measured as follows.

  Using a micro-compression tester, the conductive particles are compressed under the conditions of a compression rate of 2.6 mN / sec and a maximum test load of 10 gf with the end face of a diamond cylinder having a diameter of 50 μm. The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the compression elastic modulus can be obtained by the following formula. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value when the conductive particles are 20% or 50% compressively deformed (N)
S: Compression displacement (mm) when conductive particles are 20% or 50% compressively deformed
R: radius of conductive particles (mm)

  The compression elastic modulus universally and quantitatively represents the hardness of the conductive particles. By using the compression elastic modulus, the hardness of the conductive particles can be expressed quantitatively and uniquely.

  From the viewpoint of further improving the conduction reliability between the electrodes of the connection structure and further enhancing the conduction reliability when subjected to thermal shock or exposed to high temperature and high humidity, the above anisotropic conductive property is used. The CV value of the particle diameter of the plurality of conductive particles 5 before connection contained in the material is preferably 3% or more, more preferably 4% or more, preferably 10% or less, more preferably 7% or less.

  The coefficient of variation (CV value) of the particle diameter of the conductive particles is represented by the following formula.

CV value (%) = (ρ / Dn) × 100
ρ: Standard deviation of particle diameter of conductive particles Dn: Average value of particle diameter of conductive particles

  From the viewpoint of further improving the conduction reliability between the electrodes of the connection structure and further enhancing the conduction reliability when subjected to thermal shock or exposed to high temperature and high humidity, the cured product layer 3 is used. The CV value of the gap distance between the plurality of first and second electrodes 2b and 4b facing each other in the connected first and second connection target members 2 and 4 is preferably 10% or more, more preferably It is 14% or more, preferably 30% or less, more preferably 26% or less.

  The coefficient of variation (CV value) of the distance between the plurality of first and second electrodes 2b, 4b facing each other is expressed by the following equation.

CV value (%) = (ρ / Dn) × 100
ρ: Standard deviation of the distance between the plurality of first and second electrodes facing each other Dn: Average value of the distance between the plurality of first and second electrodes facing each other

  From the viewpoint of further improving the conduction reliability between the electrodes of the connection structure and further raising the conduction reliability when subjected to thermal shock or exposed to high temperature and high humidity, the first connection object The Young's modulus of the member 2 is preferably 10 GPa or more, more preferably 50 GPa or more, preferably 200 GPa or less, more preferably 100 GPa or less.

  From the viewpoint of further improving the conduction reliability between the electrodes of the connection structure and further raising the conduction reliability when subjected to thermal shock or exposed to high temperature and high humidity, the second connection object The Young's modulus of the member 4 is preferably 2 GPa or more, more preferably 10 GPa or more, preferably 200 GPa or less, more preferably 100 GPa or less. The Young's modulus of the second connection target member 4 may be 100 GPa or more.

  When the Young's modulus of the first and second connection target members is high and the first and second connection target members are hard, the thermal shock in the present invention is given or the high temperature and high humidity are exposed. The effect of further improving the conduction reliability is obtained.

  The Young's modulus is measured by a three-point bending method at 23 ° C. using an autograph AGS-X apparatus (manufactured by Shimadzu Corporation).

  From the viewpoint of further improving the conduction reliability of the connection structure, it is preferable that five or more conductive particles 5 are arranged on average between the first and second electrodes 2b and 4b facing each other. Preferably, 8 or more are arranged. The upper limit of the average number of the conductive particles 5 disposed between the opposing first and second electrodes 2b and 4b is not particularly limited.

  The second electrode is preferably a copper electrode. It is also preferable that at least one of the first electrode and the second electrode is a copper electrode. The anisotropic conductive material is preferably an anisotropic conductive material used for connecting a connection target member having a copper electrode. In the case where a copper electrode is formed on the connection target member, the copper electrode generally has a height variation. In particular, when forming a copper electrode by copper plating, it is difficult to form the copper electrode with a smooth surface. However, in the method for manufacturing a connection structure according to the present invention, the connection structure according to the present invention, and the anisotropic conductive material according to the present invention, even between copper electrodes having a height variation, In addition, it is possible to sufficiently ensure the conduction reliability when a thermal shock is applied or when it is exposed to high temperature and high humidity.

  The manufacturing method of the connection structure according to the present invention, the connection structure according to the present invention, and the anisotropic conductive material according to the present invention include, for example, connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), Connection between semiconductor chip and flexible printed circuit board (COF (Chip on Film)), connection between semiconductor chip and glass substrate (COG (Chip on Glass)), or connection between flexible printed circuit board and glass epoxy substrate (FOB (Film) on Board)). Especially, it is suitable for COG or FOG use, and suitable for COG use. As the first connection target member and the second connection target member, it is preferable to use a semiconductor chip and a glass substrate, or to use a flexible printed circuit board and a glass substrate, and to use a semiconductor chip and a glass substrate. Is more preferable. The first connection target member and the second connection target member are preferably a semiconductor chip and a glass substrate, or a flexible printed circuit board and a glass substrate, and are a semiconductor chip and a glass substrate. It is more preferable.

  In COG applications, in particular, it is often difficult to reliably connect the electrodes of the semiconductor chip and the glass substrate with conductive particles of an anisotropic conductive material. For example, in the case of COG use, the distance between adjacent electrodes of a semiconductor chip and the distance between adjacent electrodes of a glass substrate may be about 10 to 20 μm, and fine wiring is often formed. Even if fine wiring is formed, in the present invention, the electrodes of the semiconductor chip and the glass substrate can be connected with high accuracy, and the conduction reliability can be improved.

  In FOG applications, in particular, it is often difficult to reliably connect the electrodes of the flexible printed circuit board and the glass substrate with the conductive particles of the anisotropic conductive paste. For example, in the case of FOG use, the distance between adjacent electrodes of a flexible printed board and the distance between adjacent electrodes of a glass substrate may be about 20 to 50 μm, and fine wiring is often formed. . Even if fine wiring is formed, in the present invention, since conductive particles can be accurately placed between the electrodes, the electrodes between the flexible printed circuit board and the glass substrate can be connected with high precision, The conduction reliability can be increased.

  The connection structure 1 shown in FIG. 1 can be obtained as follows, for example, through the states shown in FIGS. Here, the manufacturing method of the connection structure 1 at the time of using the anisotropic conductive material containing a thermosetting component, a photocurable component, and several electroconductive particle as said anisotropic conductive material is demonstrated.

  As shown to Fig.2 (a), the 1st connection object member 2 which has the 1st electrode 2b in the upper surface 2a is prepared. Next, an anisotropic conductive material including a plurality of conductive particles 5 is disposed on the upper surface 2a of the first connection target member 2, and the anisotropic conductive material layer 3A is disposed on the upper surface 2a of the first connection target member 2. Form. At this time, it is preferable that one or a plurality of conductive particles 5 be arranged on the first electrode 2b.

  Next, the anisotropic conductive material layer 3A is cured by irradiating the anisotropic conductive material layer 3A with light. In FIGS. 2A to 2C, the anisotropic conductive material layer 3A is irradiated with light to advance the curing of the anisotropic conductive material layer 3A, and the anisotropic conductive material layer 3A is made into a B-stage. ing. That is, as shown in FIG. 2B, the B-stage anisotropic conductive material layer 3 </ b> B is formed on the upper surface 2 a of the first connection target member 2. By the B-stage, the first connection target member 2 and the B-staged anisotropic conductive material layer 3B are temporarily bonded. The B-staged anisotropic conductive material layer 3B is a semi-cured product in a semi-cured state. The B-staged anisotropic conductive material layer 3B is not completely cured, and thermal curing can further proceed. However, without making the anisotropic conductive material layer 3A B-stage, the anisotropic conductive material layer 3A is irradiated with light or heated to heat the anisotropic conductive material layer 3A once. It may be cured.

The light irradiation intensity for appropriately proceeding the curing of the anisotropic conductive material layer 3A is, for example, preferably about 0.1 to 100 mW / cm ² . Moreover, the irradiation energy of light for appropriately proceeding the curing of the anisotropic conductive material layer 3A is, for example, preferably about 100 to 10,000 mJ / cm ² . The light source used when irradiating light is not specifically limited. Examples of the light source include a light source having a sufficient light emission distribution at a wavelength of 420 nm or less. Specific examples of the light source include, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, and an LED lamp.

  Next, as shown in FIG. 2C, the second connection target member 4 is laminated on the upper surface 3a of the B-staged anisotropic conductive material layer 3B. The second connection target member 4 is laminated so that the first electrode 2b on the upper surface 2a of the first connection target member 2 and the second electrode 4b on the lower surface 4a of the second connection target member 4 face each other. To do.

  Further, when the second connection target member 4 is laminated, the anisotropic conductive material layer 3B that has been B-staged is further cured by heating the anisotropic conductive material layer 3B that has been B-staged, A cured product layer 3 is formed. However, the B-staged anisotropic conductive material layer 3B may be heated before the second connection target member 4 is laminated. Furthermore, you may heat the anisotropic conductive material layer 3B B-staged after the lamination | stacking of the 2nd connection object member 4. FIG.

  The heating temperature for curing the anisotropic conductive material layer 3A or the B-staged anisotropic conductive material layer 3B by heating is preferably 140 ° C. or higher, more preferably 160 ° C. or higher, preferably 250 ° C. or lower, More preferably, it is 200 degrees C or less.

  It is preferable to apply pressure when curing the B-staged anisotropic conductive material layer 3B. By compressing the conductive particles 5 with the first electrode 2b and the second electrode 4b by pressurization, the contact area between the first and second electrodes 2b, 4b and the conductive particles 5 can be increased. it can. For this reason, conduction reliability can be improved. Further, by compressing the conductive particles 5, even if the distance between the first and second electrodes 2b and 4b increases, the particle diameter of the conductive particles 5 increases so as to follow this expansion.

  By curing the B-staged anisotropic conductive material layer 3 </ b> B, the first connection target member 2 and the second connection target member 4 are connected via the cured product layer 3. Further, the first electrode 2 b and the second electrode 4 b are electrically connected through the conductive particles 5. In this way, the connection structure 1 shown in FIG. 1 can be obtained. Here, since photocuring and thermosetting are used in combination, the anisotropic conductive material can be cured in a short time.

  As a method of curing the anisotropic conductive material according to the present invention, a method of irradiating the anisotropic conductive material with light, a method of heating the anisotropic conductive material, after irradiating the anisotropic conductive material with light, Examples include a method of heating the anisotropic conductive material, and a method of irradiating the anisotropic conductive material with light after the anisotropic conductive material is heated. In addition, when the photocuring speed and the thermosetting speed are different, light irradiation and heating may be performed simultaneously. Especially, the method of heating an anisotropic conductive material after irradiating light to an anisotropic conductive material is preferable. The anisotropic conductive material can be cured in a short time by the combined use of photocuring and heat curing.

  The anisotropic conductive material is an anisotropic conductive material curable by heating, and a curable compound (thermosetting compound or light and thermosetting compound) curable by heating is used as the curable compound. May be included. The curable compound curable by heating may be a curable compound (thermosetting compound) that is not cured by light irradiation, and is curable by both light irradiation and heating (light and light). Thermosetting compound).

  The anisotropic conductive material is an anisotropic conductive material that can be cured by light irradiation. As the curable compound, a curable compound that can be cured by light irradiation (a photocurable compound or light and heat curing). A functional compound). The curable compound that can be cured by irradiation with light may be a curable compound that is not cured by heating (photocurable compound), or a curable compound that can be cured by both irradiation of light and heating (light and light). Thermosetting compound).

  The anisotropic conductive material is preferably an anisotropic conductive material that can be cured by both light irradiation and heating. The curable compound preferably contains a curable compound that can be cured by light irradiation and a curable compound that can be cured by heating. In this case, the anisotropic conductive material is semi-cured (B-stage) by light irradiation, and after the fluidity of the anisotropic conductive material is lowered, the anisotropic conductive material is easily cured by heating. be able to. The anisotropic conductive material preferably contains a thermosetting compound and a photocurable compound as the curable compound.

  Hereinafter, first, details of each component suitably used for the anisotropic conductive material according to the present invention will be described.

(Curable compound)
The curable compound contained in the anisotropic conductive material is not particularly limited. A conventionally known curable compound can be used as the curable compound. As for the said sclerosing | hardenable compound, only 1 type may be used and 2 or more types may be used together.

  The curable compound preferably contains a curable compound having an epoxy group or a thiirane group. The curable compound having an epoxy group is an epoxy compound. The curable compound having a thiirane group is an episulfide compound. As for the said curable compound which has an epoxy group or thiirane group, only 1 type may be used and 2 or more types may be used together.

  More preferably, the curable compound contains a curable compound having a thiirane group. Since the episulfide compound has a thiirane group instead of an epoxy group, it can be quickly cured at a low temperature. That is, the episulfide compound having a thiirane group can be cured at a lower temperature derived from the thiirane group as compared with the epoxy compound having an epoxy group.

  The curable compound having an epoxy group or thiirane group preferably has an aromatic ring. Examples of the aromatic ring include a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, tetracene ring, chrysene ring, triphenylene ring, tetraphen ring, pyrene ring, pentacene ring, picene ring, and perylene ring. Especially, it is preferable that the said aromatic ring is a benzene ring, a naphthalene ring, or an anthracene ring, and it is more preferable that it is a benzene ring or a naphthalene ring. A naphthalene ring is preferred because it has a planar structure and can be cured more rapidly.

  From the viewpoint of enhancing the curability of the anisotropic conductive material, the content of the curable compound having the epoxy group or thiirane group is preferably 10% by weight or more in the total 100% by weight of the curable compound. Preferably they are 20 weight% or more and 100 weight% or less. The total amount of the curable compound may be a curable compound having the epoxy group or thiirane group. When the curable compound having the epoxy group or thiirane group and another curable compound different from the curable compound having the epoxy group or thiirane group are used in combination, in the total 100% by weight of the curable compound, The content of the curable compound having an epoxy group or thiirane group is preferably 99% by weight or less, more preferably 95% by weight or less, still more preferably 90% by weight or less, and particularly preferably 80% by weight or less.

  The curable compound may further contain another curable compound different from the curable compound having an epoxy group or a thiirane group. Examples of the other curable compounds include curable compounds having an unsaturated double bond, phenol curable compounds, amino curable compounds, unsaturated polyester curable compounds, polyurethane curable compounds, silicone curable compounds, and polyimide curable compounds. Compounds and the like. As for said other curable compound, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of easily controlling the curing of the anisotropic conductive material or further improving the conduction reliability in the connection structure, the curable compound contains a curable compound having an unsaturated double bond. It is preferable to do. From the viewpoint of easily controlling the curing of the anisotropic conductive material and further improving the conduction reliability in the connection structure, the curable compound having an unsaturated double bond is a (meth) acryloyl group. It is preferable that it is a curable compound which has. By using the curable compound having the (meth) acryloyl group, the curing rate can be improved in the entire B-staged anisotropic conductive material (including the portion directly irradiated with light and the portion not directly irradiated with light). It becomes easy to control within a suitable range, and the conduction reliability in the resulting connection structure is further increased.

  From the viewpoint of easily controlling the curing rate of the B-staged anisotropic conductive material layer and further improving the conduction reliability of the resulting connection structure, the curable compound having the (meth) acryloyl group is: It is preferable to have one or two (meth) acryloyl groups.

  From the viewpoint of easily controlling the curing rate of the B-staged anisotropic conductive material layer and further improving the conduction reliability of the resulting connection structure, the curable compound having the (meth) acryloyl group is: It is preferable to have one or two (meth) acryloyl groups.

  The curable compound having the (meth) acryloyl group has no epoxy group and thiirane group, and has a (meth) acryloyl group, and has an epoxy group or thiirane group, and (meth) A curable compound having an acryloyl group may be mentioned.

  As the curable compound having the (meth) acryloyl group, an ester compound obtained by reacting a (meth) acrylic acid and a compound having a hydroxyl group, an epoxy obtained by reacting (meth) acrylic acid and an epoxy compound ( A (meth) acrylate, a urethane (meth) acrylate obtained by reacting a (meth) acrylic acid derivative having a hydroxyl group with an isocyanate, or the like is preferably used. The “(meth) acryloyl group” refers to an acryloyl group and a methacryloyl group. The “(meth) acryl” refers to acryl and methacryl. The “(meth) acrylate” refers to acrylate and methacrylate.

  The ester compound obtained by making the said (meth) acrylic acid and the compound which has a hydroxyl group react is not specifically limited. As the ester compound, any of a monofunctional ester compound, a bifunctional ester compound, and a trifunctional or higher functional ester compound can be used.

  The curable compound having an epoxy group or thiirane group and having a (meth) acryloyl group is a part of the epoxy group or part of thiirane group of the compound having two or more epoxy groups or two or more thiirane groups. It is preferable that it is a curable compound obtained by converting into a (meth) acryloyl group. This curable compound is a partially (meth) acrylated epoxy compound or a partially (meth) acrylated episulfide compound.

  The curable compound preferably contains a reaction product of a compound having two or more epoxy groups or two or more thiirane groups and (meth) acrylic acid. This reaction product is obtained by reacting a compound having two or more epoxy groups or two or more thiirane groups with (meth) acrylic acid in the presence of a basic catalyst according to a conventional method. It is preferable that 20% or more of the epoxy group or thiirane group is converted (converted) to a (meth) acryloyl group. The conversion is more preferably 30% or more, preferably 80% or less, more preferably 70% or less. Most preferably, 40% or more and 60% or less of the epoxy group or thiirane group is converted to a (meth) acryloyl group.

  Examples of the partially (meth) acrylated epoxy compound include bisphenol type epoxy (meth) acrylate, cresol novolac type epoxy (meth) acrylate, carboxylic acid anhydride-modified epoxy (meth) acrylate, and phenol novolac type epoxy (meth) acrylate. Is mentioned.

  As the curable compound, a modified phenoxy resin obtained by converting a part of epoxy groups of a phenoxy resin having two or more epoxy groups or two or more thiirane groups or a part of thiirane groups into a (meth) acryloyl group may be used. Good. That is, a modified phenoxy resin having an epoxy group or thiirane group and a (meth) acryloyl group may be used.

  The curable compound may be a crosslinkable compound or a non-crosslinkable compound.

  Specific examples of the crosslinkable compound include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, (poly ) Ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, glycerol methacrylate acrylate, pentaerythritol tri (meth) acrylate, tri Examples include methylolpropane trimethacrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, polyester (meth) acrylate, and urethane (meth) acrylate.

  Specific examples of the non-crosslinkable compound include ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) ) Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (Meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, and the like.

  When a thermosetting compound and a photocurable compound are used in combination, the blending ratio of the photocurable compound and the thermosetting compound is appropriately adjusted according to the type of the photocurable compound and the thermosetting compound. The The anisotropic conductive material preferably contains a photocurable compound and a thermosetting compound in a weight ratio of 1:99 to 90:10, more preferably 5:95 to 60:40, More preferably, it is included at 10:90 to 40:60.

(Thermosetting agent)
The anisotropic conductive material preferably contains a thermosetting agent as the thermosetting component. The thermosetting agent is not particularly limited. A conventionally known thermosetting agent can be used as the thermosetting agent. Examples of the thermosetting agent include imidazole curing agents, amine curing agents, phenol curing agents, polythiol curing agents, acid anhydrides, thermal cation curing agents, and thermal radical generators. As for the said thermosetting agent, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of curing the anisotropic conductive material more rapidly at a low temperature, the anisotropic conductive material preferably contains an imidazole curing agent, a polythiol curing agent, an amine curing agent, or a thermal cation curing agent.

  In addition, a latent curing agent is preferable because the storage stability of the anisotropic conductive material can be improved. The latent curing agent is preferably a latent imidazole curing agent, a latent polythiol curing agent or a latent amine curing agent. The thermosetting agent may be coated with a polymer material such as polyurethane resin or polyester resin.

  The imidazole curing agent is not particularly limited, and 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2, 4-Diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine and 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s- Examples include triazine isocyanuric acid adducts.

  The polythiol curing agent is not particularly limited, and examples thereof include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate. .

  The amine curing agent is not particularly limited, and hexamethylene diamine, octamethylene diamine, decamethylene diamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraspiro [5.5]. Examples include undecane, bis (4-aminocyclohexyl) methane, metaphenylenediamine, and diaminodiphenylsulfone.

  As the thermal cation curing agent, iodonium salts and sulfonium salts are preferably used. For example, commercially available products of the above-mentioned thermal cation curing agent include San-Aid SI-45L, SI-60L, SI-80L, SI-100L, SI-110L, SI-150L manufactured by Sanshin Chemical Co., Ltd., and ADEKA manufactured by ADEKA Optomer SP-150, SP-170 etc. are mentioned.

Preferred anionic moieties of the thermal cationic curing agent include PF ₆ , BF ₄ , and B (C ₆ F ₅ ) ₄ .

  From the viewpoint of further improving the connection reliability between the electrodes and the connection reliability of the connection structure under high temperature and high humidity, the anisotropic conductive material preferably contains a thermal radical generator. The thermal radical generator is not particularly limited. As the thermal radical generator, a conventionally known thermal radical generator can be used. As for the said thermal radical generator, only 1 type may be used and 2 or more types may be used together. Here, the “thermal radical generator” means a compound that generates radical species by heating.

  The thermal radical generator is not particularly limited, and examples thereof include azo compounds and peroxides. Examples of the peroxide include diacyl peroxide compounds, peroxyester compounds, hydroperoxide compounds, peroxydicarbonate compounds, peroxyketal compounds, dialkyl peroxide compounds, and ketone peroxide compounds.

  Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), and 2,2′-azobis (2,4-dimethylvaleronitrile). 1,1′-azobis-1-cyclohexanecarbonitrile, dimethyl-2,2′-azobisisobutyrate, dimethyl-2,2′-azobis (2-methylpropionate), dimethyl-1,1 ′ -Azobis (1-cyclohexanecarboxylate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-amidinopropane) dihydrochloride, 2-tert-butylazo-2-cyanopropane 2,2′-azobis (2-methylpropionamide) dihydrate, 2,2′-azobis (2,4,4-trimethylpentane), and the like.

  Examples of the diacyl peroxide compound include benzoyl peroxide, diisobutyryl peroxide, di (3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, and disuccinic acid peroxide. Examples of the peroxyester compound include cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, tert-hexylperoxyneodecanoate, and tert-butylperoxyneo. Decanoate, tert-butylperoxyneoheptanoate, tert-hexylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2 , 5-di (2-ethylhexanoylperoxy) hexane, tert-hexylperoxy-2-ethylhexanoate, tert-butylperoxypivalate, tert-butylperoxy-2-ethylhexanoate, tert -Butyl peroxyisobutyrate, tert-butyl per Kishiraureto, tert- butylperoxy isophthalate, tert- butylperoxy acetate, tert- butylperoxy octoate and tert- butyl peroxybenzoate, and the like. Examples of the hydroperoxide compound include cumene hydroperoxide and p-menthane hydroperoxide. Examples of the peroxydicarbonate compound include di-sec-butyl peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-n-propyl peroxydicarbonate, diisopropyl peroxycarbonate, and di- (2-ethylhexyl) peroxycarbonate and the like. Other examples of the peroxide include methyl ethyl ketone peroxide, potassium persulfate, and 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane.

  The decomposition temperature for obtaining the 10-hour half-life of the thermal radical generator is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, preferably 80 ° C. or lower, more preferably 70 ° C. or lower. When the decomposition temperature for obtaining the 10-hour half-life of the thermal radical generator is less than 30 ° C., the storage stability of the anisotropic conductive material tends to be lowered. It tends to be difficult to sufficiently heat cure the conductive material.

  The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, and still more preferably 5 parts by weight with respect to 100 parts by weight of the curable compound curable by heating. Above, particularly preferably 10 parts by weight or more, preferably 40 parts by weight or less, more preferably 30 parts by weight or less, and still more preferably 20 parts by weight or less. When the content of the thermosetting agent is not less than the above lower limit and not more than the above upper limit, the anisotropic conductive material can be sufficiently thermoset.

  When the thermosetting agent contains a thermal radical generator, the content of the thermal radical generator is preferably 0.01 parts by weight or more with respect to 100 parts by weight of the curable compound curable by heating. Preferably it is 0.05 weight part or more, Preferably it is 10 weight part or less, More preferably, it is 5 weight part or less. When the content of the thermal radical generator is not less than the above lower limit and not more than the above upper limit, the anisotropic conductive material can be sufficiently thermoset.

(Photocuring initiator)
The anisotropic conductive material preferably contains a photocuring initiator as the photocuring component. The photocuring initiator is not particularly limited. A conventionally known photocuring initiator can be used as the photocuring initiator. From the viewpoint of further improving the connection reliability between the electrodes and the connection reliability of the connection structure, the anisotropic conductive material preferably contains a photoradical generator. As for the said photocuring initiator, only 1 type may be used and 2 or more types may be used together.

  The photocuring initiator is not particularly limited, and is not limited to acetophenone photocuring initiator (acetophenone photoradical generator), benzophenone photocuring initiator (benzophenone photoradical generator), thioxanthone, ketal photocuring initiator (ketal photoradical). Generator), halogenated ketones, acyl phosphinoxides, acyl phosphonates, and the like. Examples of the photocuring initiator include a photocationic initiator.

  Specific examples of the acetophenone photocuring initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, methoxy Examples include acetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, and 2-hydroxy-2-cyclohexylacetophenone. Specific examples of the ketal photocuring initiator include benzyldimethyl ketal.

  The anisotropic conductive material preferably contains a photocationic initiator. By using a photocation initiator, curing of the anisotropic conductive material after light irradiation can be rapidly advanced. Furthermore, the anisotropic conductive material layer portion that is blocked by the conductive particles and not directly irradiated with light can be sufficiently cured by the cation reaction due to the action of the photocation initiator.

  Examples of the photocationic curing agent include iodonium-based photocationic curing agents, oxonium-based photocationic curing agents, and sulfonium-based photocationic curing agents. Examples of the iodonium-based photocationic curing agent include bis (4-tert-butylphenyl) iodonium hexafluorophosphate. Examples of the oxonium-based photocationic curing agent include trimethyloxonium tetrafluoroborate. Examples of the sulfonium-based photocationic curing agent include tri-p-tolylsulfonium hexafluorophosphate and triphenylsulfonium bromide. Of these, a sulfonium-based photocationic curing agent is preferable from the viewpoint of further improving the curability of the anisotropic conductive material and further enhancing the conduction reliability between the electrodes.

  The content of the photocuring initiator is not particularly limited. For 100 parts by weight of the curable compound curable by light irradiation, the content of the photocuring initiator (the content of the photocationic initiator when the photocuring initiator is a photocationic initiator) is , Preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, preferably 2 parts by weight or less, more preferably 1 part by weight or less. When the content of the photocuring initiator is not less than the above lower limit and not more than the above upper limit, the anisotropic conductive material can be appropriately photocured. By irradiating the anisotropic conductive material with light to form a B stage, the flow of the anisotropic conductive material can be suppressed.

(Conductive particles)
The conductive particles contained in the anisotropic conductive material electrically connect the electrodes of the first and second connection target members. The surface of the conductive layer may be covered with an insulating layer. The surface of the conductive layer of the conductive particles may be covered with insulating particles. In these cases, the insulating layer or insulating particles between the conductive layer and the electrode are excluded when the connection target member is connected. Examples of the conductive particles include conductive particles obtained by coating the surfaces of organic particles, inorganic particles, organic-inorganic hybrid particles, or metal particles with a metal layer, and metal particles that are substantially composed of only metal. It is done. The metal layer is not particularly limited. Examples of the metal layer include a gold layer, a silver layer, a copper layer, a nickel layer, a palladium layer, and a metal layer containing tin.

  From the viewpoint of further improving the conduction reliability between the electrodes, the conductive particles preferably include resin particles and a conductive layer disposed on the surface of the resin particles.

  The content of the conductive particles is not particularly limited. The content of the conductive particles in 100% by weight of the anisotropic conductive material is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, still more preferably 1% by weight or more, preferably 40% by weight. % Or less, more preferably 30% by weight or less, still more preferably 19% by weight or less. A conductive particle can be easily arrange | positioned between the upper and lower electrodes which should be connected as content of the said electroconductive particle is more than the said minimum and below the said upper limit. Furthermore, it becomes difficult to electrically connect adjacent electrodes that should not be connected via a plurality of conductive particles. That is, a short circuit between adjacent electrodes can be further prevented.

(Other ingredients)
The anisotropic conductive material preferably contains a filler. By using the filler, the thermal expansion coefficient of the cured product of the anisotropic conductive material can be suppressed. Specific examples of the filler include silica, aluminum nitride, alumina, glass, boron nitride, silicon nitride, silicone, carbon, graphite, graphene, and talc. As for a filler, only 1 type may be used and 2 or more types may be used together. When a filler having a high thermal conductivity is used, the main curing time is shortened.

  The anisotropic conductive material may contain a solvent. By using the solvent, the viscosity of the anisotropic conductive material can be easily adjusted. Examples of the solvent include ethyl acetate, methyl cellosolve, toluene, acetone, methyl ethyl ketone, cyclohexane, n-hexane, tetrahydrofuran, and diethyl ether.

(Details and applications of anisotropic conductive materials)
The anisotropic conductive material is a paste-like or film-like anisotropic conductive material, and is preferably a paste-like anisotropic conductive material. The paste-like anisotropic conductive material is an anisotropic conductive paste. The film-like anisotropic conductive material is an anisotropic conductive film. When the anisotropic conductive material is an anisotropic conductive film, a film that does not include conductive particles may be laminated on the anisotropic conductive film that includes the conductive particles.

  The anisotropic conductive material is an anisotropic conductive paste, and is preferably an anisotropic conductive paste applied on a connection target member in a paste state.

  The viscosity of the anisotropic conductive paste at 25 ° C. is preferably 20 Pa · s or more, more preferably 100 Pa · s or more, preferably 700 Pa · s or less, more preferably 300 Pa · s or less. When the viscosity is equal to or higher than the lower limit, sedimentation of conductive particles in the anisotropic conductive paste can be suppressed. When the viscosity is equal to or lower than the upper limit, the dispersibility of the conductive particles is further increased. If the viscosity of the anisotropic conductive paste before coating is within the above range, after applying the anisotropic conductive paste on the first connection target member, the flow of the anisotropic conductive paste before curing is further increased. Further suppression is possible, and voids are further less likely to occur.

The elastic modulus at 23 ° C. after curing of the anisotropic conductive material is preferably 0.8 GPa or more, and preferably 3 GPa or less. The above-mentioned elastic modulus after curing is measured under the conditions of a temperature rising rate of 5 ° C./min, a deformation rate of 0.1% and 10 Hz using “Viscoelasticity measuring device DVA-200” manufactured by IT Measurement & Control Co., Ltd.

  The ratio of the 50% K value (GPa) of the conductive particles to the elastic modulus (GPa) after curing of the anisotropic conductive material (50% K value / elastic modulus) is preferably 0.2 or more, preferably Is 1.8 or less.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited only to the following examples.

  Conductive particles A to S shown in Tables 1 and 2 were prepared. Each of the conductive particles A to S has a metal layer in which a nickel plating layer is formed on the surface of the divinylbenzene resin particle and a gold plating layer is formed on the surface of the nickel plating layer. Particles. The compression recovery rate and compression modulus (20% K value and 50% K value) were adjusted by changing the monomer composition of divinylbenzene resin particles.

Example 1
(1) Preparation of anisotropic conductive paste An episulfide compound-containing mixture containing 70% by weight of resorcinol diglycidyl ether and 30% by weight of an episulfide compound having a structure represented by the following formula (1B) was prepared.

  15 parts by weight of the above episulfide compound-containing mixture, 3 parts by weight of an amine adduct (“PN-23J” manufactured by Ajinomoto Fine Techno Co.) as a thermosetting agent, and epoxy acrylate (“EBECRYL 3702” manufactured by Daicel-Cytec Co., Ltd.) as a photocurable compound ”) 8 parts by weight, 0.2 part by weight of an acylphosphine oxide compound (“ DAROCUR TPO ”manufactured by Ciba Japan) as a photopolymerization initiator, and 2-ethyl-4-methylimidazole 1 as a curing accelerator 100 parts by weight of an anisotropic conductive paste in which 20 parts by weight of silica having an average particle diameter of 0.25 μm and 20 parts by weight of alumina having an average particle diameter of 0.5 μm are blended to further obtain conductive particles A % So that the content in 10% by weight becomes 10% by weight, and then using a planetary stirrer at 2000 rpm. By stirring minutes to obtain an anisotropic conductive paste. The elastic modulus after curing of the anisotropic conductive paste was 2.8 GPa.

(2) Production of connection structure Production of connection structure (COG):
A glass substrate (first connection target member) having an Al—Si electrode (thickness: 500 nm) having a pitch of 30 μm, an electrode size of 20 μm × 100 μm, and an interelectrode distance of 10 μm on the upper surface was prepared. Also, a Si chip (size 15, 1 mm × 1.6 mm × 0.3 mm) having 726 Au electrodes (height 12 μm) with a pitch of 30 μm, an electrode size of 20 μm × 100 μm, and an interelectrode distance of 10 μm on the lower surface of the outer periphery of the chip ( A second connection target member) was prepared. The first and second electrode heights in the first and second connection target members, the absolute value of the difference between the maximum value and the minimum value of the first electrode height, and the maximum value of the second electrode height Table 1 below shows the absolute value of the difference between the minimum value and the Young's modulus of the first and second connection target members.

  On the said glass substrate, the anisotropic conductive paste immediately after preparation was applied using a dispenser so that it might become width 1.5mm and thickness 40 micrometers, and the anisotropic conductive paste layer was formed. Next, UV irradiation was performed for 10 seconds under a condition of 200 mW at a wavelength of 365 nm by an LED-UV irradiator, and the anisotropic conductive paste was made into a B-stage. The Si chip was laminated on the B-staged anisotropic conductive paste layer so that the electrodes face each other. After that, using “BD-02” manufactured by Ohashi Manufacturing Co., Ltd., the temperature of the thermocompression bonding head was adjusted to 170 ° C. (main press bonding temperature), and applied to the upper surface of the Si chip. The pressure-bonding head was placed, and the anisotropic conductive paste layer was cured at 170 ° C. for 10 seconds under a pressure of 1 MPa to obtain a connection structure (COG).

  The cross section of the obtained connection structure (COG) was exposed and the cross section was observed. The average value of the gap distance between the first and second electrodes and the CV value of the gap distance were determined.

(Examples 2 to 10 and Comparative Examples 1 and 2)
Kind of conductive particles used in anisotropic conductive paste, first and second electrode heights in first and second connection target members, difference between maximum value and minimum value of first electrode height Except that the absolute value of, the absolute value of the difference between the maximum and minimum values of the second electrode height, and the Young's modulus of the first and second connection target members are changed as shown in Table 1 below. An anisotropic conductive paste was prepared in the same manner as in Example 1, and a connection structure (COG) was obtained using the anisotropic conductive paste.

(Example 11)
An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the conductive particles A were changed to the conductive particles J.

Fabrication of connection structure (FOG):
A glass substrate (first connection target member) having an aluminum electrode (first electrode) pattern having an L / S of 17 μm / 17 μm and a length of 1 mm on the upper surface was prepared. In addition, a flexible printed circuit board (second connection target member) having a Ni-plated Ni electrode (second electrode) pattern having a L / S of 17 μm / 17 μm and a length of 2 mm on the lower surface was prepared. The first and second electrode heights in the first and second connection target members, the absolute value of the difference between the maximum value and the minimum value of the first electrode height, and the maximum value of the second electrode height Table 2 below shows the absolute value of the difference between the value and the minimum value and the Young's modulus of the first and second connection target members.

  A connection structure (FOG) was obtained in the same manner as the connection structure (COG) of Example 1 except that these first and second connection target members were used.

  The cross section of the obtained connection structure (FOG) was exposed and the cross section was observed. The average value of the gap distance between the first and second electrodes and the CV value of the gap distance were determined.

(Examples 12 to 18 and Comparative Examples 3 to 5)
Kind of conductive particles used in anisotropic conductive paste, first and second electrode heights in first and second connection target members, difference between maximum value and minimum value of first electrode height Except that the absolute value of, the absolute value of the difference between the maximum and minimum values of the second electrode height, and the Young's modulus of the first and second connection target members are changed as shown in Table 2 below. An anisotropic conductive paste was prepared in the same manner as in Example 11, and a connection structure (FOG) was obtained using the anisotropic conductive paste.

(Evaluation)
(1) Capture rate of conductive particles between electrodes (conducting accuracy of conductive particles)
The number of conductive particles present between the upper and lower electrodes facing each other in the obtained connection structure was counted with an optical microscope. The capture rate of conductive particles was determined according to the following criteria.

[Criteria for trapping rate of conductive particles]
○: 10 or more particles between each electrode Δ: 8 or 9 particles between each electrode ×: 7 or less particles between each electrode

(2) Conductivity Using the obtained connection structure, resistance values at 20 locations were evaluated by a four-terminal method. The conduction reliability was determined according to the following criteria.

[Judgment criteria for conduction reliability]
○: The resistance value is 3Ω or less in all locations. Δ: There is one or more locations where the resistance value is 3Ω or more. ×: There is one or more locations that are not conducting at all.

(3) Connection reliability when subjected to thermal shock 100 obtained connection structures are held at −40 ° C. for 5 minutes, then heated to 125 ° C. in 25 minutes, and held at 125 ° C. for 5 minutes. After that, a cold cycle test was performed in which the process of lowering the temperature to −40 ° C. in 25 minutes was one cycle. After 1000 cycles, the connection structure was removed.

  About 100 connection structures after the thermal cycle test, it was evaluated whether or not conduction failure between the upper and lower electrodes occurred. Of the 100 connection structures, the case where the number of defective conductions is 1 or less is “◯”, the case of 2 or more, 3 or less is “Δ”, the case of 4 or more It was determined as “x”.

(4) Moisture and heat resistance test After 15 pieces of the obtained connection structures were left under conditions of 85 ° C. and 85% RH for 1000 hours, the conductivity was evaluated in the same manner. When the result in the continuity determination criterion in (2) is “◯”, “◯” when the result in the continuity determination criterion is “△”, and the result in the continuity determination criterion When “x” becomes “x”, it was determined as “x”.

(5) Indentation state About the connection part of the electroconductive particle and electrode in the obtained connection structure, the state of the indentation formed in the electrode was observed.

Using a polarizing microscope, it was judged that a good indentation was formed when a clear spherical indentation could be confirmed per electrode 200 μm ² . The indentation state was determined according to the following criteria.

[Indentation criteria]
○○: Indentation is very dark ○: Indentation is deep ×: Indentation is thin

  The results are shown in Tables 1 and 2 below.

DESCRIPTION OF SYMBOLS 1 ... Connection structure 2 ... 1st connection object member 2a ... Upper surface 2b ... 1st electrode 3 ... Hardened | cured material layer 3a ... Upper surface 3A ... Anisotropic conductive material layer 3B ... B-staged anisotropic conductive material Layer 4 ... second connection target member 4a ... lower surface 4b ... second electrode 5 ... conductive particles

Claims (15)

Disposing an anisotropic conductive material layer on the upper surface of a first connection target member having a plurality of first electrodes on the upper surface using an anisotropic conductive material containing a curable component and a plurality of conductive particles When,
A second connection target member having a plurality of second electrodes on the lower surface is laminated on the upper surface of the anisotropic conductive material layer with the plurality of first electrodes and the plurality of second electrodes facing each other. And a process of
Curing the anisotropic conductive material layer to form a cured product layer, and electrically connecting the first and second connection target members by the cured product layer,
The plurality of second electrode heights are 5 μm or more and 20 μm or less, respectively.
An absolute value of a difference between a maximum value and a minimum value of the plurality of second electrode heights is 0.5 μm or more and 2 μm or less;
The average particle diameter of the plurality of conductive particles before connection contained in the anisotropic conductive material is 2 μm or more and 20 μm or less,
The average value of the compression recovery rate when the plurality of conductive particles before connection contained in the anisotropic conductive material is 20% compressively deformed is 20% or more and 50% or less, and
The manufacturing method of the connection structure whose average value of the compression recovery rate when the said some electroconductive particle before the connection contained in the said anisotropic conductive material is 50% compressively deformed is 5% or more and 25% or less. The plurality of first electrode heights are 0.05 μm or more and 10 μm or less,
2. The method for manufacturing a connection structure according to claim 1, wherein an absolute value of a difference between a maximum value and a minimum value of the plurality of first electrode heights is 0 μm or more and 5 μm or less.   An average particle diameter of a plurality of conductive particles before connection included in the anisotropic conductive material is a plurality of the first and second connection members facing each other in the first and second connection target members connected by the cured product layer. The manufacturing method of the connection structure according to claim 1 or 2, wherein the average value of the distance between the second electrodes is 1.1 times or more and 5 times or less.   The average value of the gap distance between the plurality of first and second electrodes facing each other in the first and second connection target members connected by the cured product layer is 1 μm or more and 15 μm or less. The manufacturing method of the connection structure of any one of claim | item 1-3.   The connection structure according to any one of claims 1 to 4, wherein a CV value of a particle diameter of the plurality of conductive particles before connection included in the anisotropic conductive material is 3% or more and 10% or less. Body manufacturing method.   The CV value of the distance between the plurality of facing first and second electrodes in the first and second connection target members connected by the cured product layer is 10% or more and 30% or less. The manufacturing method of the connection structure of any one of Claims 1-5. A first connection target member having a plurality of first electrodes on the upper surface;
A second connection target member having a plurality of second electrodes on the lower surface;
A cured product layer formed by curing an anisotropic conductive material that electrically connects the first and second connection target members and includes a curable component and a plurality of conductive particles. Prepared,
The plurality of second electrode heights are 5 μm or more and 20 μm or less, respectively.
An absolute value of a difference between a maximum value and a minimum value of the plurality of second electrode heights is 0.5 μm or more and 2 μm or less;
The average particle diameter of the plurality of conductive particles before connection contained in the anisotropic conductive material is 2 μm or more and 20 μm or less,
The average value of the compression recovery rate when the plurality of conductive particles before connection contained in the anisotropic conductive material is 20% compressively deformed is 20% or more and 50% or less, and
A connection structure in which an average value of a compression recovery rate when a plurality of the conductive particles before connection included in the anisotropic conductive material is 50% compressed and deformed is 5% or more and 25% or less. The plurality of first electrode heights are 0.05 μm or more and 10 μm or less,
The connection structure according to claim 7, wherein an absolute value of a difference between a maximum value and a minimum value of the plurality of first electrode heights is 0 μm or more and 5 μm or less.   An average particle diameter of a plurality of conductive particles before connection included in the anisotropic conductive material is a plurality of the first and second connection members facing each other in the first and second connection target members connected by the cured product layer. The connection structure according to claim 7 or 8, which is 1.1 times or more and 5 times or less of an average value of a gap distance between the second electrodes.   The average value of the gap distance between the plurality of first and second electrodes facing each other in the first and second connection target members connected by the cured product layer is 1 μm or more and 15 μm or less. Item 10. The connection structure according to any one of Items 7 to 9.   The connection structure according to any one of claims 7 to 10, wherein a CV value of a particle diameter of the plurality of conductive particles before connection included in the anisotropic conductive material is 3% or more and 10% or less. body.   The CV value of the distance between the plurality of facing first and second electrodes in the first and second connection target members connected by the cured product layer is 10% or more and 30% or less. The connection structure according to any one of claims 7 to 11. In order to form a cured product layer that electrically connects a first connection target member having a plurality of first electrodes on the upper surface and a second connection target member having a plurality of second electrodes on the lower surface. An anisotropic conductive material used,
Including a curable component and a plurality of conductive particles;
The plurality of second electrode heights are 5 μm or more and 20 μm or less, respectively.
An absolute value of a difference between a maximum value and a minimum value of the plurality of second electrode heights is 0.5 μm or more and 2 μm or less;
The average particle diameter of the plurality of conductive particles is 2 μm or more and 20 μm or less,
The average value of the compression recovery rate when the plurality of conductive particles are 20% compressed and deformed is 20% or more and 50% or less, and
An anisotropic conductive material having an average compression recovery rate of 5% or more and 25% or less when the plurality of conductive particles are 50% compressed and deformed. The plurality of first electrode heights are 0.05 μm or more and 10 μm or less,
The anisotropic conductive material according to claim 13, wherein an absolute value of a difference between a maximum value and a minimum value of the plurality of first electrode heights is 0 μm or more and 5 μm or less.   The anisotropic conductive material according to claim 13 or 14, wherein a CV value of a particle diameter of the plurality of conductive particles is 3% or more and 10% or less.

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