JP6002500B2 - Method for manufacturing connection structure - Google Patents

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 method for manufacturing a connecting structure.

  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, the first circuit electrode and the first insulating film are formed adjacent to each other on the main surface of the first circuit board. The second circuit member in which the second circuit electrode and the second insulating film are formed adjacent to each other on the main surface of the second circuit board, and the main surface of the first circuit member There is disclosed a method for manufacturing a connection structure that includes a circuit connection member that is provided between a main surface of the second circuit member and connects the first and second circuit members. In at least one of the first and second circuit members, at least a part of the insulating film is formed thicker than the circuit electrode with respect to the main surface of the circuit board. In the manufacturing method of the connection structure described in Patent Document 1, a film-like circuit connection material is disposed between the main surface of the first circuit board and the main surface of the second circuit board, and the first And the first circuit member and the second circuit member are connected by heating and pressurizing and curing the circuit connection material via the second circuit member, and the first circuit electrode and The second circuit electrode is electrically connected through the conductive particles.

WO2005 / 002002A1

  In the conventional manufacturing method of the connection structure as described in Patent Document 1, the conductive particles may not be accurately arranged between the upper and lower electrodes to be connected. For example, on the electrode, there may be a case where conductive particles are unevenly distributed because conductive particles are partially disposed in a large amount and conductive particles are partially disposed in a small amount.

  Further, for example, when the circuit member containing conductive particles is disposed on the first circuit member, and the first circuit member and the second circuit member are pressure-bonded via the circuit member, the circuit member In some cases, the conductive particles contained in the metal particles move on the electrode and flow to an unintended region. For example, many conductive particles may flow in a region on the side of the electrode, that is, a region where there is no electrode. For this reason, the total number of conductive particles disposed between the upper and lower electrodes may be reduced. In consideration of the flow of the conductive particles to an unintended region, it may be necessary to use an anisotropic conductive material including a larger number of conductive particles. When the amount of the conductive particles used increases, the manufacturing cost of the connection structure increases. Furthermore, as a result of the conductive particles getting wet and spread to unintended areas, contamination may occur in the resulting connection structure.

  The objective of this invention is providing the manufacturing method of the connection structure which can arrange | position electroconductive particle between electrodes accurately and can improve the conduction | electrical_connection reliability between electrodes.

  According to a wide aspect of the present invention, a first electrode and an insulating film that covers the first electrode and has a plurality of openings so that the first electrode is partially exposed are formed on the surface. On the surface of the first connection target member, the first electrode and the first connection target member using an anisotropic conductive material containing a curable component and conductive particles. A step of laminating an anisotropic conductive material layer with the anisotropic conductive material so as to cover the insulating film, and on the surface opposite to the first connection target member side of the anisotropic conductive material layer, A step of laminating a second connection target member having a second electrode on the surface thereof with the first electrode and the second electrode facing each other, and a cured product obtained by curing the anisotropic conductive material layer Forming a layer, and electrically connecting the first and second connection target members by the cured product layer, As the anisotropic conductive material, the lowest melt viscosity at 60 to 150 ° C. is 1000 Pa · s or more, using the anisotropic conductive material is less than 10000 Pa · s, the manufacturing method of the connecting structure is provided.

  On the specific situation with the manufacturing method of the connection structure which concerns on this invention, the aspect-ratio of the said 1st electrode is 10 or more.

  In another specific aspect of the method for manufacturing a connection structure according to the present invention, the first electrode has a length direction and a width direction, and the insulating film has a length direction of the first electrode. Or two or more of the openings arranged at a distance in the width direction of the first electrode, or the insulating film has two or more of the openings arranged at a distance in the width direction of the first electrode.

  In still another specific aspect of the method for manufacturing a connection structure according to the present invention, a total opening area of the plurality of openings of the insulating film on the first electrode is an upper area of the first electrode. 3/10 or more.

  In another specific aspect of the manufacturing method of the connection structure according to the present invention, an average value of the opening diameters per one of the plurality of openings of the insulating film on the first electrode is the conductive particles. It is 1.5 times or more and 15 times or less of the average particle diameter.

In still another specific aspect of the method for manufacturing a connection structure according to the present invention, at least one of the first and second connection target members is a semiconductor chip, and the upper area of the first electrode is 500 μm. ² or less.

  In another specific aspect of the method for manufacturing a connection structure according to the present invention, the insulating film has a thickness of 50 nm or more and 2 μm or less.

  In the method for manufacturing a connection structure according to the present invention, it is preferable to use a paste-like anisotropic conductive paste as the anisotropic conductive material.

  In another specific aspect of the method for manufacturing a connection structure according to the present invention, the anisotropic conductive material is a paste-like anisotropic conductive paste that can be cured by light irradiation and heating. When the conductive conductive material layer was cured, the anisotropic conductive material layer was irradiated with light to advance the curing to form a B-staged anisotropic conductive material layer, and then the B-staged The anisotropic conductive material layer is heated and cured to form the cured product layer.

  A method for manufacturing a connection structure according to the present invention includes: a first electrode; an insulating film that covers the first electrode and has a plurality of openings so that the first electrode is partially exposed; On the surface of the first connection target member, using the first connection target member having a surface of the first connection target member, and using an anisotropic conductive material containing a curable component and conductive particles. A step of laminating an anisotropic conductive material layer with the anisotropic conductive material so as to cover the electrode and the insulating film, and a surface opposite to the first connection target member side of the anisotropic conductive material layer A step of laminating a plurality of second connection target members having a plurality of second electrodes on the surface, the plurality of first electrodes and the plurality of second electrodes facing each other; and the anisotropy The conductive material layer is cured to form a cured product layer, and the cured product layer electrically connects the first and second connection target members. And an anisotropic conductive material having a minimum melt viscosity of 1000 Pa · s to 10,000 Pa · s at 60 to 150 ° C. is used as the anisotropic conductive material. Conductive particles can be accurately placed between the electrodes, and the conduction reliability between the electrodes can be improved.

FIG. 1 is a 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. FIG. 2 is an enlarged plan view schematically showing the first electrode and the insulating film in the first connection target member used in the method for manufacturing the connection structure according to the embodiment of the present invention. 3A to 3C are cross-sectional views for explaining each step of the method for manufacturing the connection structure according to the embodiment of the present invention. FIG. 4 is a schematic cross-sectional view for explaining the angle formed by the inner peripheral surface of the opening of the insulating film and the lower surface of the insulating film.

  Details of the present invention will be described below.

  In the method for manufacturing a connection structure according to the present invention, the first connection object member having the first electrode on the surface and the second connection object member having the second electrode on the surface are electrically connected. It is a manufacturing method of a structure. The first electrode and the second electrode are electrically connected by conductive particles.

  A method for manufacturing a connection structure according to the present invention includes: a first electrode; an insulating film that covers the first electrode and has a plurality of openings so that the first electrode is partially exposed; The 1st connection object member which has is on the surface is used. Furthermore, an anisotropic conductive material containing a curable component and conductive particles is used. Moreover, the 2nd connection object member which has a 2nd electrode on the surface is used.

  In the manufacturing method of the connection structure according to the present invention, the anisotropic conductive material is used by the anisotropic conductive material so as to cover the first electrode and the insulating film on the surface of the first connection target member. A step of laminating layers, and the second connection target member on the surface of the anisotropic conductive material layer opposite to the first connection target member side, the first electrode and the second electrode The step of laminating the electrodes facing each other, the cured anisotropic conductive material layer is cured to form a cured product layer, and the first and second connection target members are electrically connected by the cured product layer. A process. The first and second electrodes are electrically connected by the conductive particles contained in the cured product layer.

  In the method for manufacturing a connection structure according to the present invention, as the anisotropic conductive material, an anisotropic conductive material having a minimum melt viscosity η2 of 1000 Pa · s or more and 10,000 Pa · s or less in a measurement temperature range of 60 to 150 ° C. Is used.

  Since the manufacturing method of the connection structure which concerns on this invention is equipped with the said structure, an electroconductive particle can be arrange | positioned accurately between electrodes and the conduction | electrical_connection reliability between electrodes can be improved. In particular, since the insulating film has an opening, the conductive particles can be accurately arranged in the opening. Furthermore, the fact that the minimum melt viscosity of the anisotropic conductive material is not less than the above lower limit and not more than the above upper limit greatly contributes to accurately arranging conductive particles in the opening portion of the insulating film. The conduction reliability is effectively increased.

  The minimum melt viscosity η2 at 60 to 150 ° C. of the anisotropic conductive material is 1000 Pa · s or more and 10,000 Pa · s or less, more preferably 7000 Pa · s or less, and further preferably 4500 Pa · s or less. When the anisotropic conductive material is an anisotropic conductive paste and is B-staged, the minimum melt viscosity after B-stage is preferably within the above range. If the minimum melting temperature of the anisotropic conductive material is not less than the above lower limit and not more than the above upper limit, the void discharge and the capture rate of the conductive particles are improved.

  The minimum melt viscosity η2 of the anisotropic conductive material is obtained by measuring the minimum complex viscosity η * using a rheometer. The measurement conditions are strain control 1 rad, frequency 1 Hz, temperature rising rate 20 ° C./min, and measurement temperature range 60 to 150 ° C. In addition, generally the temperature which shows the minimum value of the viscosity of the anisotropic conductive material which has curability exists in the range of 60-150 degreeC. Moreover, it is preferable that the said anisotropic conductive material shows the minimum value of a viscosity at 60-150 degreeC. The measurement temperature range of the minimum melt viscosity η2 is more preferably 60 to 120 ° C, still more preferably 70 to 100 ° C, and it is preferable that a temperature showing the minimum value of the viscosity exists in these temperature ranges.

  Examples of the rheometer include STRESTTECH (manufactured by EOLOGICA). The minimum melting temperature of the anisotropic conductive material is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, preferably 150 ° C. or lower, more preferably 120 ° C. or lower.

  Viscosity ratio (η2 / η3) of viscosity η2 (Pa · s) at 1 Hz at a temperature showing the minimum melt viscosity of the anisotropic conductive material to viscosity η3 (Pa · s) at 10 Hz at a temperature showing the minimum melt viscosity ) Is preferably 2 or more, more preferably 3 or more, and still more preferably 4 or more. If the viscosity ratio (η2 / η3) is greater than or equal to the lower limit, voids are less likely to occur in the cured product layer. When the viscosity ratio (η2 / η3) is 3 or more, voids are hardly generated in the cured product layer.

  Furthermore, when the viscosity ratio (η2 / η3) is equal to or greater than the lower limit, the anisotropic conductive material can be prevented from unintentionally spreading before or during curing, and contamination in the connection structure is less likely to occur. be able to. Therefore, if the viscosity ratio (η2 / η3) is equal to or higher than the lower limit, the void is suppressed in the cured product layer and the contamination is caused by the flow of the anisotropic conductive material layer or the B-staged anisotropic conductive material layer. Both effects can be obtained. The upper limit of the viscosity ratio (η2 / η3) is not particularly limited, but the viscosity ratio (η2 / η3) is preferably 8 or less.

  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 obtained by the manufacturing method of the connection structure which concerns on one Embodiment of this invention is typically shown with sectional drawing. In FIG. 2, the 1st electrode and insulating film in the 1st connection object member used for the manufacturing method of the connection structure which concerns on one Embodiment of this invention are expanded and shown with a top view. In FIG. 2, the figure seen from the insulating film side is shown. Note that FIG. 1 shows a cross-sectional view in the width direction of the first electrode shown in FIG.

  A connection structure 1 shown in FIG. 1 includes a first connection target member 2, a second connection target member 4, and a cured product layer 3. The cured product layer 3 electrically connects the first connection target member 2 and the second connection target member 4 and is a connection portion. The cured product layer 3 is formed by curing an anisotropic conductive material including a curable component and a plurality of conductive particles 5. In the connection structure 1, a glass substrate is used as the first connection target member 2, and a flexible printed circuit board is used as the second connection target member 4.

  The said 1st, 2nd connection object member is not specifically limited. Specific examples of the first and second connection target members include electronic components such as semiconductor chips, capacitors, and diodes, and electronic circuit boards such as printed boards, flexible printed boards, glass boards, and glass epoxy boards. Examples include parts. It is preferable that at least one of the first and second connection target members is a semiconductor chip.

  The first connection object member 2 has a plurality of first electrodes 2b on the surface (upper surface) 2a. The first electrode 2b protrudes from the surface 2a. The second connection target member 4 has a plurality of second electrodes 4b on the surface 4a. The plurality of second electrodes 4b protrude from the surface 4a. The first electrode 2 b and the second electrode 4 b are electrically connected by a plurality of conductive particles 5.

  The first electrode is preferably rectangular and preferably has a length direction and a width direction. The aspect ratio of the first electrode is preferably 2 or more, more preferably 5 or more, and still more preferably 10 or more. The upper limit of the aspect ratio of the first electrode is not particularly limited. The aspect ratio of the first electrode may be 100, for example. When the aspect ratio of the first electrode is not less than the above lower limit (particularly not less than 10), it is generally difficult to accurately dispose the conductive particles on the first electrode, but the connection according to the present invention. Even if the aspect ratio of the first electrode is equal to or higher than the lower limit, the conductive particles can be accurately arranged on the first electrode by the structure manufacturing method.

  The second electrode is preferably rectangular and preferably has a length direction and a width direction. The aspect ratio of the second electrode is not particularly limited. The aspect ratio of the second electrode is preferably 1.2 or more, more preferably 1.5 or more, and further preferably 2 or more. The upper limit of the aspect ratio of the second electrode is not particularly limited. The aspect ratio of the second electrode may be 100, for example, and the aspect ratio of the second electrode may be 100 or less. When the aspect ratio of the second electrode is not less than the above lower limit (particularly not less than 2), it is generally difficult to accurately place the conductive particles between the first and second electrodes. According to the connection structure manufacturing method according to the present invention, even when the aspect ratio of the second electrode is equal to or higher than the lower limit, the conductive particles can be accurately arranged between the first and second electrodes.

  The aspect ratio indicates the ratio of the lengthwise dimension to the widthwise dimension (lengthwise dimension / widthwise dimension).

  Further, the first connection target member 2 has an insulating film 2c on the surface 2a that covers the first electrode 2b and has a plurality of openings X so that the first electrode 2b is partially exposed. . The insulating film 2c covers a part of the region on the first electrode 2b. In the portion where the conductive particles 5 are in contact with the first electrode 2b, the plurality of first electrodes 2b are not covered with the insulating film 2c. The insulating film 2c is not disposed between the first electrode 2b and the conductive particles 5. In the opening X portion, the first electrode 2b is exposed. The insulating film 2c has a plurality of openings X. The opening X penetrates the upper surface and the lower surface of the insulating film 2c. Between the 1st electrode 2b and the electroconductive particle 5, the component except the insulating film 2c and the electroconductive particle 5 in the hardened | cured material layer 3 is not arrange | positioned. Between the 2nd electrode 4b and the electroconductive particle 5, the component except the electroconductive particle 5 in the hardened | cured material layer 3 is not arrange | positioned.

  The first electrode 2b has a length direction and a width direction. The insulating film 2c has 48 openings X on one first electrode 2b. On one of the first electrodes, the insulating film has two or more openings, preferably four or more, preferably 10 or more, and more preferably 20 or more.

  On one first electrode 2b, the insulating film 2c has 16 openings X arranged at a distance in the length direction of the first electrode 2b. Preferably, the first electrode has a length direction and a width direction, and the insulating film preferably has two or more openings arranged at a distance in the length direction of the first electrode. More preferably, it is more preferable that it is 10 or more. In this case, since the conductive particles are easily dispersed and arranged in many opening portions arranged in the length direction, the conduction reliability is further enhanced.

  On one first electrode 2b, the insulating film 2c has three openings X arranged at a distance in the width direction of the first electrode 2b. Preferably, the first electrode has a length direction and a width direction, and the insulating film preferably has two or more openings arranged at a distance in the width direction of the first electrode. More preferably, it is more preferable that it has 5 or more. In this case, since the conductive particles are easily dispersed and arranged in many opening portions arranged in the width direction, the conduction reliability is further enhanced.

  In the length direction of the first electrode, the openings may be linearly arranged, zigzag-shaped, or randomly arranged. In the width direction of the first electrode, the openings may be linearly arranged, zigzag-shaped, or randomly arranged.

  In particular, the first electrode has two or more openings arranged at a distance in the length direction of the first electrode, and is arranged at a distance in the width direction of the first electrode. It is preferable to have two or more openings. In this case, since the conductive particles can be effectively dispersed and arranged on the first electrode, the conduction reliability is further enhanced.

  The total opening area of the plurality of openings of the insulating film on the one first electrode is preferably 1/10 or more of the upper area of the first electrode, and preferably 3/10 or more. More preferred. Thus, when the opening area is equal to or more than the lower limit of the upper area, the conductive particles can easily enter the opening, and the first electrode and the conductive particles can be efficiently contacted. it can. The total opening area of a plurality of openings of the insulating film on one of the first electrodes is preferably 9/10 or less of the upper area of the first electrode, and is preferably 7/10 or less. More preferred. Thus, when the opening area is less than or equal to the upper limit of the upper area, the conductive particles are difficult to be disposed on the insulating film, and the conductive particles are easily disposed in the opening. An electrode and the said electroconductive particle can be made to contact efficiently.

  A total opening area of a plurality of openings of the insulating film on one first electrode is 1/10 or more of an upper area of a portion covered with the insulating film of the first electrode. Preferably, it is 3/10 or more. As described above, when the opening area is equal to or more than the lower limit of the upper area covered, the conductive particles easily enter the opening, and the first electrode and the conductive particles are efficiently contacted. Can be made. The total opening area of the plurality of openings of the insulating film on one first electrode is 9/10 or less of the upper area of the portion covered with the insulating film of the first electrode. Preferably, it is 7/10 or less. Thus, when the opening area is equal to or less than the upper limit of the upper area covered, the conductive particles are hardly disposed on the insulating film, and the conductive particles are easily disposed in the opening. The first electrode and the conductive particles can be efficiently contacted.

  The average value of the opening diameter per one of the plurality of openings of the insulating film on the first electrode is preferably 1.5 times or more, more preferably 2 times or more of the average particle diameter of the conductive particles, Preferably it is 15 times or less, More preferably, it is 8 times or less. The opening diameter indicates the maximum diameter in one opening. In addition, the said electroconductive particle arrange | positioned in one opening may be one, and plural may be sufficient as it.

  The “average particle size” of the conductive particles indicates a number average particle size. The average particle diameter of the conductive particles can be obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

The area on the first electrode is preferably 22000Myuemu ² or less, more preferably 20000Myuemu ² or less, more preferably 1000 .mu.m ² or less, particularly preferably 500 [mu] m ² or less. When the upper area of the first electrode is equal to or less than the upper limit, the plurality of conductive particles are easily disposed on the first electrode. The area on the portion covered by the insulating film of the first electrode is preferably 20000Myuemu ² or less, more preferably 1000 .mu.m ² or less, more preferably 500 [mu] m ² or less, particularly preferably 450 [mu] m ² or less. When the upper area covered with the first electrode is equal to or less than the upper limit, the plurality of conductive particles are easily disposed on the first electrode.

  The insulating film may cover the entire surface of the first electrode except for the opening, or may cover a part of the first electrode. The insulating film on the first electrode may be covered with a transparent electrode (ITO, IZO, etc.). The opening of the first electrode may be covered with a transparent electrode (ITO, IZO, etc.).

  The insulating film may cover the whole or a part other than the electrodes. Thereby, corrosion of wiring can be prevented.

  The thickness of the insulating film is preferably 10 nm or more, more preferably 50 nm or more, preferably 10 μm or less, more preferably 2 μm or less. The thickness of the insulating film is preferably 1/20 or more, more preferably 1/10 or more, preferably 9/10 or less, more preferably 1/2 or less of the average particle diameter of the conductive particles. When the thickness of the insulating film is equal to or more than the lower limit, the conductive particles are more easily disposed in the opening portion, and the conduction reliability between the electrodes is further enhanced. When the thickness of the insulating film is less than or equal to the upper limit, the conductive particles and the first and second electrodes are more likely to come into contact with each other, and the conduction reliability between the electrodes is further increased. The thickness of the insulating film is the thickness of the insulating film excluding the opening.

  As shown in FIG. 4, the angle α formed by the inner peripheral surface of the opening X of the insulating film 2c and the lower surface of the insulating film 2c is preferably 30 ° or more, more preferably 40 ° or more, and preferably 75 ° or less. Preferably it is 60 degrees or less. When the angle is at least the lower limit, the capture rate of the conductive particles is further increased. When the angle is not more than the upper limit, the conductive particles are easily dispersed and arranged, for example, the conductive particles are easily distributed over the entire surface of the electrode.

  As the conductive particles, conductive particles having protrusions on the surface may be used. When the conductive particles have protrusions on the surface, the thickness of the insulating film is preferably larger than the height of the protrusions on the surface of the conductive particles. The thickness of the insulating film is more preferably 1.1 times or more the height of the protrusion on the surface of the conductive particles. In this case, the flow of the conductive particles once disposed in the opening is further less likely to occur. For this reason, conduction | electrical_connection reliability becomes still higher. The size of the conductive particle protrusion is preferably 20 times or less of the roughness Ra of the electrode surface.

  The first electrode is preferably a copper electrode. The connection resistance is lowered by using a copper electrode. On the other hand, there is a problem that the copper electrode is easily oxidized. On the other hand, the oxidation of the copper electrode can be suppressed by disposing the insulating film so as to cover the copper electrode. Moreover, the oxidation of a copper electrode can be effectively suppressed, so that the upper area of the copper electrode covered with the said insulating film is large. Moreover, even if it is aluminum other than a copper electrode, copper alloy, or aluminum alloy, the said 1st electrode is corrosive gas in air | atmosphere by arrange | positioning the said insulating film so that the said 1st electrode may be covered. It can suppress that it contacts and degrades.

  The connection structure 1 shown in FIG. 1 can be obtained as follows, for example. Here, as the anisotropic conductive material, an anisotropic conductive material including a photocurable component curable by light irradiation, a thermosetting component curable by heating, and the conductive particles 5 is used. A method for manufacturing the connection structure 1 will be specifically described. That is, the manufacturing method of the connection structure 1 at the time of using the anisotropic conductive paste which can be hardened | cured by light irradiation and a heating is demonstrated. Instead of the photocurable component and the thermosetting component, only a photocurable component that can be cured by light irradiation may be used, or only a thermosetting component that can be cured by heating, Light and thermosetting components that can be cured by both light irradiation and heating may be used.

  First, the surface 2a (first electrode 2b) and the insulating film 2c that covers the first electrode 2b and has a plurality of openings X so that the first electrode 2b is partially exposed. The first connection target member 2 is prepared.

  The connection target member having the first electrode 2b and before the insulating film 2c is formed is used to cover the first electrode 2b on the first electrode 2b of the connection target member. And the process of forming the insulating film 2c which has several opening X so that the 1st electrode 2b may be partially exposed, and obtaining the 1st connection object member 2 may be provided.

  Next, as shown in FIG. 3A, the anisotropic conductive material is arranged (applied) on the surface 2a of the first connection target member 2, and the anisotropic conductive material layer 3A is laminated. At this time, it is preferable that one or a plurality of conductive particles 5 be arranged in the opening X in the insulating film 2c on the first electrode 2b. Even if the conductive particles 5 are arranged not on the opening X but on the insulating film 2c, the conductive particles 5A are melted when the anisotropic conductive material layer 3A or the B-staged anisotropic conductive material layer 3B is melted. When the conductive particles 5 flow, the conductive particles 5 easily move into the openings X that are concave portions. In particular, when an anisotropic conductive paste is used, the conductive particles 5 easily move into the opening X. On the other hand, the conductive particles 5 arranged in the opening X which is a recess are difficult to move out of the opening X.

  The thickness of the anisotropic conductive material layer 3A is preferably 1.2 times or more of the average particle diameter of the conductive particles 5, preferably 2 times or more, more preferably 3 times or more, It is preferably 20 times or less, and more preferably 10 times or less.

  Next, the anisotropic conductive material layer 3A is cured by irradiating the anisotropic conductive material layer 3A with light. 3A to 3C, 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. (B-stage process). That is, as shown in FIG. 3B, the B-stage anisotropic conductive material layer 3 </ b> B is formed on the 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. Curing of the anisotropic conductive material layer 3A may be advanced by heating instead of light irradiation. When the anisotropic conductive material layer 3A contains a solvent, the anisotropic conductive material layer 3B may be formed in a B-stage by removing the solvent of the anisotropic conductive material layer 3A. Further, for example, the anisotropic conductive material layer 3A may be cured at a time by heating the anisotropic conductive material layer 3A without forming the B layer of the anisotropic conductive material layer 3A.

Light irradiation intensity for effectively advancing the curing of the anisotropic conductive material layer 3A, for example, is preferably 0.1~6000mW / cm ^2, more preferably 100~4000mW / cm ² More preferably, it is 1000 to 3000 mW / cm ² . The integrated light quantity is preferably 0.1 to 10 J / 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. 3C, the second connection target member 4 is formed on the surface 3a opposite to the first connection target member 2 side of the B-staged anisotropic conductive material layer 3B. Are stacked. The second connection target member 4 is laminated so that the first electrode 2b on the surface 2a of the first connection target member 2 and the second electrode 4b on the 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 heated by heating the anisotropic conductive material layer 3B that has been B-staged, The cured product layer 3 is formed (main curing process). However, the B-staged anisotropic conductive material layer 3B may be heated before the second connection target member 4 is laminated. Furthermore, the B-staged anisotropic conductive material layer 3 </ b> B may be heated after the second connection target member 4 is laminated. The B-staged anisotropic conductive material layer 3B may be fully cured by light irradiation instead of heating.

  The heating temperature for curing the anisotropic conductive material layer 3B that has been B-staged by heating is preferably 140 ° C. or higher, more preferably 160 ° C. or higher, preferably 250 ° C. or lower, more preferably 200 ° C. or lower. .

  It is preferable to apply pressure when the B-staged anisotropic conductive material layer 3B is fully cured. 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.

  In this way, 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. As a result, the connection structure 1 shown in FIG. 1 can be obtained. In this embodiment, since photocuring and thermosetting are used together, the anisotropic conductive material can be cured in a short time.

  At the time of producing the connection structure, the anisotropic conductive material layer formed of the anisotropic conductive material is made B-stage by applying heat or irradiating with light, and then heated to be fully cured. The conductive particles contained in the conductive material layer or the B-stage anisotropic conductive material layer are difficult to flow excessively in the curing stage. Accordingly, the conductive particles are easily arranged in a predetermined region. Specifically, conductive particles can be arranged between the upper and lower electrodes to be connected, and the adjacent electrodes that should not be connected are further prevented from being electrically connected via a plurality of conductive particles. it can. For this reason, the insulation reliability and conduction | electrical_connection reliability between electrodes in a connection structure can be improved further.

  In the method for manufacturing a connection structure according to the present invention, when the anisotropic conductive material layer is cured using a paste-like anisotropic conductive material that can be cured by light irradiation and heating, anisotropic conductive material is used. After the material layer is irradiated with light to cure and form a B-staged anisotropic conductive material layer, the B-staged anisotropic conductive material layer is heated to be fully cured and cured. It is preferable to form a physical layer.

  In addition, when the connection structure is manufactured, the anisotropic conductive material layer formed of the anisotropic conductive material layer is converted into a B stage by irradiation with light, and then heated to be fully cured, thereby forming a B stage. The cured state in the anisotropic conductive material layer thus formed can be controlled easily and accurately. For this reason, it can further suppress that the electroconductive particle contained in the anisotropic conductive material layer by which B-stage was carried out flows too much in this hardening stage. Accordingly, the conductive particles are easily arranged in a predetermined region. For this reason, the insulation reliability and conduction | electrical_connection reliability between electrodes in a connection structure can be improved further.

  The connection structure manufacturing method according to the present invention includes, for example, a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), a connection between a semiconductor chip and a flexible printed circuit board (COF (Chip on Film)), It can be used for 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)), or the like.

  The manufacturing method of the connection structure according to the present invention is suitable for FOG use or COG use. In the manufacturing method of the connection structure according to the present invention, a flexible printed circuit board and a glass substrate are used as the first connection object member and the second connection object member, or a semiconductor chip and a glass substrate are used. Is preferred.

  In COG applications, in particular, it is often difficult to reliably connect the electrodes of the semiconductor chip and the glass substrate with the conductive particles contained in the 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, the method for manufacturing a connection structure according to the present invention enables the conductive particles to be accurately placed between the electrodes, so that there is high accuracy between the electrodes of the semiconductor chip and the glass substrate. It is possible to improve the conduction reliability.

  For COG applications, both the semiconductor chip and the glass substrate are particularly hard. For this reason, the insulation reliability and conduction | electrical_connection reliability in a connection structure tend to become low. On the other hand, in this invention, even if it is a case where a hard semiconductor chip and a glass substrate are connected, insulation reliability and conduction | electrical_connection reliability can fully be improved.

  In COG applications, since L / S is a relatively narrow pitch, if the anisotropically conductive material is not sufficiently fluid when heated, the anisotropically conductive material is not sufficiently filled between electrode lines. In many cases, the reliability of conduction and the generation of voids in the cured product layer become problems. On the other hand, in the manufacturing method of the connection structure which concerns on this invention, in COG use, the conduction | electrical_connection reliability between electrodes can be improved effectively and generation | occurrence | production of the void in a hardened | cured material layer can be suppressed effectively.

  In FOG applications, since the L / S is relatively wide, the particle size of the conductive particles is large and the concentration is low, so the pressure at the time of connection is low, sufficient indentation and resin filling properties cannot be obtained, and conduction reliability between electrodes And the occurrence of voids in the cured product layer is often a problem. On the other hand, in the manufacturing method of the connection structure according to the present invention, the conduction reliability between the electrodes can be effectively enhanced in the FOG application, and the generation of voids in the cured product layer is effectively achieved. Can be suppressed.

  Examples of the material for forming the insulating film include inorganic components and organic components. Examples of the inorganic component include inorganic compounds containing a silicon atom. Examples of the inorganic compound containing a silicon atom include silicon oxide, silicon nitride, and silicon dioxide. The insulating film is preferably formed of a compound containing silicon, and is preferably formed of silicon nitride or silicon dioxide. As the organic component, silicon carbonitride, benzocyclobutene, (meth) acrylic resin, polyester resin, polyimide resin, polyamide resin, polyurethane resin, and polyepoxy resin are preferable.

  The elastic modulus of the cured product layer obtained by curing the anisotropic conductive material is preferably 100 MPa or more, preferably 4 GPa or less at 25 ° C., and further 85 ° C., preferably 10 MPa or more, preferably 3 GPa or less. When the elastic modulus is not less than the above lower limit and not more than the above upper limit, connection reliability when receiving a thermal history is increased.

  The glass transition temperature Tg of the cured layer obtained by curing the anisotropic conductive material is preferably 60 ° C. or higher, and preferably 180 ° C. or lower. When the glass transition temperature is not less than the above lower limit and not more than the above upper limit, the connection reliability of the connection structure when receiving a thermal history is increased.

  The average thermal expansion coefficient of −30 ° C. to 85 ° C. of the cured layer obtained by curing the anisotropic conductive material is preferably 110 ppm / ° C. or less, more preferably 70 ppm / ° C. or less. When the average coefficient of thermal expansion is not less than the above lower limit and not more than the above upper limit, the connection reliability of the connection structure when receiving a thermal history is increased.

  The elastic modulus and the Tg are measured using a viscoelasticity measuring device DVA-200 (manufactured by IT Measurement & Control Co., Ltd.) under conditions of a heating rate of 5 ° C./min, a deformation rate of 0.1% and 10 Hz. The temperature at the peak of tan δ is defined as Tg (glass transition point).

  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 cured by irradiating the anisotropic conductive material with light to form a B-stage and then further irradiating with light to fully cure the anisotropic conductive material. A method of further curing by heating after B-stage, a method of further curing by heating to a B-stage by irradiating light to the anisotropic conductive material, and heating the anisotropic conductive material Then, after making the B stage, there is a method of further irradiating light to perform the main curing. In addition, when the photocuring speed and the thermosetting speed are different, light irradiation and heating may be performed simultaneously. In the B-stage forming step, the anisotropic conductive material is cured by light irradiation to form a B-staged anisotropic conductive material layer. It is preferable to fully cure the B-staged anisotropic conductive material layer. By the combined use of photocuring and heat curing, the anisotropic conductive material can be efficiently cured in a short time.

  Furthermore, when using the anisotropic conductive paste, as a method of curing the anisotropic conductive paste, after removing the solvent of the anisotropic conductive paste to make a B-stage, further curing is performed by irradiating light. And a method in which the solvent is removed from the anisotropic conductive paste to form a B-stage, followed by further heating and main-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. Can be made. The curable component contained in the anisotropic conductive material preferably includes a photocurable component capable of being irradiated with light and a thermosetting component capable of being cured by heating. Moreover, it is preferable that the said sclerosing | hardenable component contained in the said anisotropic conductive material contains the light and thermosetting component which can be hardened | cured by both irradiation of light and a heating.

  Hereinafter, each component included in the anisotropic conductive material and details of each component preferably included 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.

  Examples of the curable compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenolic compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds. 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 of the entire B-staged anisotropic conductive material (including the part directly irradiated with light and the part not directly irradiated with light) Can be controlled within a suitable range, and the conduction reliability in the resulting connection structure is further enhanced.

  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 portions of the thermal cationic curing agent include SbF ₆ , 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 is 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 is sufficiently thermally cured.

(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 conductive particles are not particularly limited as long as they are conductive particles. The said electroconductive particle should just have an electroconductive part on the electroconductive surface. The surface of the conductive part of the conductive particles may be covered with an insulating material. In this case, the insulating material between the conductive portion and the electrode is excluded when the connection target member is connected. Examples of the conductive particles include organic particles, inorganic particles excluding metals, organic / inorganic hybrid particles, or conductive particles whose surfaces are covered with a conductive layer (metal layer), or substantially only metal. Metal particles to be used. The conductive part is not particularly limited. Gold, silver, copper, nickel, palladium, tin, etc. are mentioned as a metal which comprises the said electroconductive part. Examples of the conductive layer include a gold layer, a silver layer, a copper layer, a nickel layer, a palladium layer, or a conductive layer containing tin.

  From the viewpoint of increasing the contact area between the electrode and the conductive particle and further enhancing the conduction reliability between the electrodes, the conductive particle is composed of a resin particle and a conductive layer (on the surface of the resin particle ( First conductive layer). From the viewpoint of further improving the conduction reliability between the electrodes, the conductive particles are preferably conductive particles having at least a conductive outer surface of a low melting point metal layer. More preferably, the conductive particles include resin particles and a conductive layer disposed on the surface of the resin particles, and at least the outer surface of the conductive layer is a low melting point metal layer.

The low melting point metal layer is a layer containing a low melting point metal. The low melting point metal is a metal having a melting point of 450 ° C. or lower. The melting point of the low melting point metal is preferably 300 ° C. or lower, more preferably 160 ° C. or lower. The low melting point metal layer preferably contains tin. In 100% by weight of the metal contained in the low melting point metal layer, the content of tin is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 70% by weight or more, and particularly preferably 90% by weight or more. . When the content of the low melting point metal layer is not less than the lower limit, the connection reliability between the low melting point metal layer and the electrode is further enhanced. The tin content is determined using a high frequency inductively coupled plasma optical emission spectrometer (“ICP-AES” manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer (“EDX-800HS” manufactured by Shimadzu). It can be measured.

  When the outer surface of the conductive portion is a low melting point metal layer, the low melting point metal layer is melted and joined to the electrodes, and the low melting point metal layer conducts between the electrodes. For example, since the low-melting point metal layer and the electrode are not in point contact but in surface contact, the connection resistance is lowered. Further, the use of conductive particles having at least a conductive outer surface of the low melting point metal layer increases the bonding strength between the low melting point metal layer and the electrode. It becomes difficult to occur, and the conduction reliability is effectively increased.

  The low melting point metal which comprises the said low melting metal layer is not specifically limited. The low melting point metal is preferably tin or an alloy containing tin. Examples of the alloy include a tin-silver alloy, a tin-copper alloy, a tin-silver-copper alloy, a tin-bismuth alloy, a tin-zinc alloy, and a tin-indium alloy. Especially, since it is excellent in the wettability with respect to an electrode, it is preferable that the said low melting metal is a tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, and a tin-indium alloy. More preferred are a tin-bismuth alloy and a tin-indium alloy.

  The low melting point metal layer is preferably a solder layer. Although the material which comprises the said solder layer is not specifically limited, Based on JISZ3001: welding term, it is preferable that it is a filler material whose liquidus is 450 degrees C or less. Examples of the solder composition include metal compositions containing zinc, gold, lead, copper, tin, bismuth, indium and the like. Among them, a tin-indium system (117 ° C. eutectic) or a tin-bismuth system (139 ° C. eutectic) which is low-melting and lead-free is preferable. That is, the solder layer preferably does not contain lead, and is preferably a solder layer containing tin and indium or a solder layer containing tin and bismuth.

  In order to further enhance the bonding strength between the low melting point metal layer and the electrode, the low melting point metal layer is made of nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth. Further, it may contain a metal such as manganese, chromium, molybdenum and palladium. From the viewpoint of further increasing the bonding strength between the low melting point metal and the electrode, the low melting point metal preferably contains nickel, copper, antimony, aluminum, or zinc. From the viewpoint of further increasing the bonding strength between the low melting point metal layer and the electrode, the content of these metals for increasing the bonding strength is 100 wt% of the low melting point metal layer, preferably 0.0001 wt% or more, Preferably it is 1 weight% or less.

  The conductive particles include resin particles and a conductive layer disposed on the surface of the resin particles, and the outer surface of the conductive layer is a low-melting metal layer, and the resin particles and the low-melting metal In addition to the low melting point metal layer, it is preferable to have a second conductive layer between the layers (such as solder layers). In this case, the low melting point metal layer is a part of the entire conductive layer, and the second conductive layer is a part of the entire conductive layer.

  The second conductive layer different from the low melting point metal layer preferably contains a metal. The metal constituting the second conductive layer is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and alloys thereof. Further, tin-doped indium oxide (ITO) may be used as the metal. As for the said metal, only 1 type may be used and 2 or more types may be used together.

  The second conductive layer is preferably a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably a nickel layer or a gold layer, and even more preferably a copper layer. The conductive particles preferably have a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably have a nickel layer or a gold layer, and still more preferably have a copper layer. By using the conductive particles having these preferable conductive layers for the connection between the electrodes, the connection resistance between the electrodes is further reduced. In addition, a low melting point metal layer can be more easily formed on the surface of these preferable conductive layers. The second conductive layer may be a low melting point metal layer such as a solder layer. The conductive particles may have a plurality of low melting point metal layers.

  The thickness of the low melting point metal layer is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, preferably 50 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less, particularly preferably. 3 μm or less. When the thickness of the low melting point metal layer is not less than the above lower limit, the conductivity is sufficiently high. When the thickness of the low melting point metal layer is not more than the above upper limit, the difference in thermal expansion coefficient between the resin particles and the low melting point metal layer becomes small, and the low melting point metal layer is hardly peeled off.

  When the conductive layer is a conductive layer other than the low melting point metal layer, or when the conductive layer has a multilayer structure, the total thickness of the conductive layer is preferably 0.1 μm or more, more preferably 0.5 μm or more, Preferably it is 1 micrometer or more, Preferably it is 50 micrometers or less, More preferably, it is 10 micrometers or less, More preferably, it is 5 micrometers or less, Most preferably, it is 3 micrometers or less.

  The particle diameter of the conductive particles is preferably 100 μm or less, more preferably 20 μm or less, still more preferably less than 20 μm, still more preferably 15 μm or less, and particularly preferably 10 μm or less. The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more. From the viewpoint of further improving the connection reliability of the connection structure when subjected to a thermal history, the average particle diameter of the conductive particles is particularly preferably 1 μm or more and 10 μm or less, and is 1 μm or more and 4 μm or less. Most preferred.

  Since the size is suitable for the conductive particles in the anisotropic conductive material and the distance between the electrodes can be further reduced, the average particle diameter of the conductive particles is in the range of 1 μm to 100 μm. Is particularly preferred.

  The resin particles can be properly used depending on the electrode size or land diameter of the substrate to be mounted.

  From the viewpoint of more reliably connecting the upper and lower electrodes and further suppressing the short circuit between the electrodes adjacent in the lateral direction, the ratio of the average particle diameter C of the conductive particles to the average particle diameter A of the resin particles ( C / A) is more than 1.0, preferably 3.0 or less. Further, when the first conductive layer is present between the resin particles and the solder layer, the ratio of the average particle size B of the resin particles to the average particle size B of the conductive particle portion excluding the solder layer (B / A) is greater than 1.0, preferably 2.0 or less. Further, when there is the first conductive layer between the resin particles and the solder layer, the average particle diameter B of the conductive particle portion excluding the solder layer having the average particle diameter C of the conductive particles including the solder layer. The ratio (C / B) to is more than 1.0, preferably 2.0 or less. When the ratio (B / A) is within the above range or the ratio (C / B) is within the above range, electrodes that are more reliably connected between the upper and lower electrodes and that are adjacent in the lateral direction The short circuit between them can be further suppressed.

Anisotropic conductive materials for FOB and FOF applications:
The anisotropic conductive material is used for connection between a flexible printed circuit board and a glass epoxy board (FOB (Film on Board)), or between a flexible printed circuit board and a flexible printed circuit board (FOF (Film on Film)). Preferably used.

  In FOB and FOF applications, L & S, which is the size of a portion (line) with an electrode and a portion (space) without an electrode, is generally 100 to 500 μm. The average particle diameter of the resin particles used for FOB and FOF applications is preferably 10 to 100 μm. When the average particle diameter of the resin particles is 10 μm or more, the thickness of the anisotropic conductive material disposed between the electrodes and the connection portion is sufficiently increased, and the adhesive force is further increased. When the average particle diameter of the resin particles is 100 μm or less, a short circuit is more unlikely to occur between adjacent electrodes.

Anisotropic conductive materials for flip chip applications:
The anisotropic conductive material is suitably used for flip chip applications.

  For flip chip applications, the land diameter is generally 15-80 μm. The average particle size of the resin particles used for flip chip applications is preferably 1 to 15 μm. When the average particle diameter of the resin particles is 1 μm or more, the thickness of the solder layer disposed on the surface of the resin particles can be sufficiently increased, and the electrodes can be more reliably electrically connected. it can. When the average particle diameter of the resin particles is 10 μm or less, a short circuit is more unlikely to occur between adjacent electrodes.

Anisotropic conductive material for COF:
The anisotropic conductive material is preferably used for connection between a semiconductor chip and a flexible printed board (COF (Chip on Film)).

  In a COF application, L & S, which is a dimension between a portion (line) with an electrode and a portion (space) without an electrode (space), is generally 10 to 50 μm. The average particle diameter of the resin particles used for COF applications is preferably 1 to 10 μm. When the average particle diameter of the resin particles is 1 μm or more, the thickness of the solder layer disposed on the surface of the resin particles can be sufficiently increased, and the electrodes can be more reliably electrically connected. it can. When the average particle diameter of the resin particles is 10 μm or less, a short circuit is more unlikely to occur between adjacent electrodes.

  The “average particle size” of the conductive particles indicates a number average particle size. The average particle diameter of the conductive particles can be obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

  The surface of the conductive particles may be insulated with an insulating material, insulating particles, flux, or the like. Insulating materials such as insulating particles, flux, and the like are preferably removed from the connection portion by being softened and flowed by heat at the time of connection. Thereby, the short circuit between electrodes can be suppressed.

  When the anisotropic conductive material is pasty, the viscosity (25 ° C.) of the anisotropic conductive material is preferably in the range of 20,000 to 300,000 mPa · s. If the viscosity is too low, the conductive particles may settle. If the viscosity is too high, the conductive particles may not be sufficiently dispersed. The paste form includes liquid.

  When a low melting point metal layer is used for the conductive layer and the low melting point metal layer is on the outermost surface of the conductive particles, the thickness of the oxide film formed on the outermost surface is preferably 10 nm or less. If it is 10 nm or less, the oxide film is destroyed by the pressure applied when the connection structure is connected, and good connection is possible. The thickness of the oxide film can be measured by TEM.

  The compressive elastic modulus of the conductive particles is preferably 1 GPa or more, more preferably 2 GPa or more, preferably 7 GPa or less, more preferably 5 GPa or less.

  The compression recovery rate of the conductive particles is preferably 20% or more, more preferably 30% or more, preferably 60% or less, more preferably 50% or less.

  The compressive elastic modulus (10% K value) at 23 ° C. 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.

10% K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value when the conductive particles are 10% compressively deformed (N)
S: Compression displacement (mm) when the conductive particles are 10% 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.

  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 is applied to the inversion load value (5.00 mN) in the central direction of the conductive particle 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

  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, even more preferably 20% by weight or less, still more preferably 19% by weight or less, and particularly preferably 10% 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 preferably further contains a curing accelerator. By using a curing accelerator, the curing rate can be further increased. As for a hardening accelerator, only 1 type may be used and 2 or more types may be used together.

  Specific examples of the curing accelerator include imidazole curing accelerators and amine curing accelerators. Of these, imidazole curing accelerators are preferred. In addition, an imidazole hardening accelerator or an amine hardening accelerator can be used also as an imidazole hardening agent or an amine hardening agent.

  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.

  From the viewpoint of further improving the connection reliability of the connection structure when subjected to a thermal history, the anisotropic conductive material preferably contains a thixotropic agent. Examples of the thixotropic agent include elastomer particles and silica. Examples of the elastomer particles include rubber particles. Examples of the rubber particles include natural rubber particles, isoprene rubber particles, butadiene rubber particles, styrene butadiene rubber particles, chloroprene rubber particles, and acrylonitrile butadiene rubber particles. The silica is preferably nano silica. The average particle diameter of the nano silica is less than 1000 nm.

  In 100% by weight of the anisotropic conductive material, the content of the thixotropic agent is preferably 0.1% by weight or more, more preferably 1% by weight or more, preferably 30% by weight or less, more preferably 15% by weight or less. It is. When the content of the thixotropic agent is not less than the above lower limit and not more than the above upper limit, the connection reliability of the connection structure when receiving a thermal history is further enhanced.

  From the viewpoint of further improving the connection reliability of the first and second connection structures, it is preferable that the insulating film and the anisotropic conductive material each contain an adhesion-imparting agent. Examples of the adhesion-imparting agent include a coupling agent and a flexible material.

  In 100% by weight of the anisotropic conductive material, the content of the adhesion-imparting agent is preferably 1% by weight or more, more preferably 5% by weight or more, preferably 50% by weight or less, more preferably 25% by weight or less. . When the content of the adhesion imparting agent is not less than the above lower limit and not more than the above upper limit, the connection reliability of the first and second connection target members is further increased.

  The anisotropic conductive material may contain an ion trapper or the like for the purpose of reducing impurity ions. When the protruding electrode of the first connection object member is Cu, the amount of extracted ion impurities in the cured insulating film and the anisotropic conductive material is preferably 10 ppm or less, more preferably 1 ppm or less. When measuring the amount of extracted ion impurities, weigh accurately about 1 g of anisotropic conductive material in a D test tube (18 × 180 m / m), inject 10 ml of purified water with a whole pipette, and seal the ampoule. Ions are extracted while shaking at 100 ° C. for 20 hours. Thereafter, the extracted ion impurities are measured using IONEX DX-320J and DIONEX ICS-1000.

  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.

  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.

  In Examples and Comparative Examples, the following components were used to form a cured product layer that connects the first and second connection target members.

[Thermosetting compound]
Episulfide compound 1B having a structure represented by the following formula (1B)

  EP-3300P (manufactured by ADEKA, flexible epoxy resin)

[Photocurable compound]
EBECRYL 3702 (manufactured by Daicel-Cytec, fatty acid-modified epoxy acrylate)
4HBAGE (Nippon Kasei Co., Ltd., 4-hydroxybutyl acrylate glycidyl ether)

[Thermosetting agent]
TEP-2E4MZ (Nippon Soda Co., Ltd., Inclusion Imidazole)

[Photocuring initiator]
Irgacure 819 (BASF)

[Adhesive agent]
KBE-402 (manufactured by Shin-Etsu Chemical Co., Ltd., silane coupling agent)

[Filler]
Surface methylated silica (average particle size 0.7mm, manufactured by Tokuyama)

[Thixotropic agent]
Nanosilica PM20L (manufactured by Tokuyama)

[Flexible particles]
KW-8800 (manufactured by Mitsubishi Rayon Co., Ltd., core-shell particles)

[Conductive particles]
The conductive particles A to E are all conductive particles having a metal layer in which a nickel plating layer is formed on the surface of the divinylbenzene resin particles and a gold plating layer is formed on the surface of the nickel plating layer. is there. Moreover, the specific gravity and average particle diameter of electroconductive particle AE are as follows.

Conductive particles A (average particle size 3 μm, 10% K value: 4.5 N / mm ² )
Conductive particles B (average particle size 3 μm, 10% K value: 5.2 N / mm ² )
Conductive particles C (average particle size 5 μm, 10% K value: 3.2 N / mm ² )
Conductive particles D (average particle size 7 μm, 10% K value: 2.8 N / mm ² )
Conductive particles E (conductive particles having protrusions with a height of 100 nm on the conductive surface, average particle diameter of 3 μm, 10% K value: 4.5 N / mm ² )

Example 1
(1) Preparation of anisotropic conductive paste The components shown in Table 1 below were blended in the blending amounts shown in Table 1 below, and the resulting mixture was stirred for 5 minutes at 2000 rpm using a planetary stirrer to obtain a blend. It was. The obtained blend was filtered using a nylon filter paper (pore diameter 10 μm) to obtain an anisotropic conductive paste having a conductive particle content of 8% by weight.

(2) Production of connection structure An electrode having a length of 1000 μm, a width of 40 μm, and a pitch of 80 μm was formed on a glass substrate having a thickness of 0.7 mm. The electrode was formed to have a thickness of Ti / Al / Ti = 15/180/50 nm from the glass side.

After forming the electrode, the entire surface was covered with SiN to form an insulating film having a thickness of 900 nm. The insulating film on the upper surface of the electrode was opened by dry etching using a photomask in a length of 14 μm and a width of 14 μm in two rows in the electrode width direction and 32 rows in the length direction. In this way, the opening size is a square having a length of 14 μm and a width of 14 μm, and a total of 64 openings are arranged on a single electrode in a straight line with 32 pieces in the length direction and two pieces in the width direction. An insulating film having a total opening area of 12544 μm ² was formed. As a result of cross-sectional observation of the insulating film in the periphery of the opening, the angle α formed by the inner peripheral surface of the opening of the insulating film and the lower surface of the insulating film was 40 °.

  Further, an ITO film having a thickness of 55 nm was formed, and the other part of the ITO film was removed by etching so as to remain only in the opening (insulation film opening) on the electrode upper surface and the SiN portion on the electrode upper surface. Thus, a first connection target member was obtained. The surface roughness Ra of the ITO film was 20 nm.

  An electrode was formed on a polyimide film with a thickness of 25 μm at L / S = 40/40 μm so that Cu / Ni / Au = 18 μm / 5 μm / 50 nm from the polyimide side. In this way, the 2nd connection object member was obtained.

  The obtained anisotropic conductive paste was applied to a thickness of 20 μm on the surface of the first connection target member on which the electrode and the insulating film were arranged to form an anisotropic conductive material layer.

Next, using an ultraviolet irradiation lamp, the anisotropic conductive material layer is irradiated with ultraviolet rays from above for 3 seconds so that the irradiation energy is 500 mJ / cm ^2, and the anisotropic conductive material layer is cured by photopolymerization. The anisotropic conductive material layer which was advanced and B-staged (semi-cured) and B-staged was formed.

  Next, on the surface opposite to the first connection target member side of the B-staged anisotropic conductive material layer, the second connection target member was laminated so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the B-staged anisotropic conductive material layer becomes 190 ° C., on the surface opposite to the side where the electrode of the second connection target member is arranged A pressure heating head was placed, and a B-staged anisotropic conductive material layer was cured at 190 ° C. for 20 seconds by applying a pressure of 3 MPa to obtain a connection structure.

(Example 2)
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 B when the anisotropic conductive paste was prepared. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 3)
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 C when the anisotropic conductive paste was prepared. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

Example 4
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 D when the anisotropic conductive paste was prepared. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 5)
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 E when the anisotropic conductive paste was prepared. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 6)
The size of the opening of the insulating film of the first connection target member is a square having a length of 10 μm and a width of 10 μm, and 40 pieces in the length direction and three pieces in the width direction are arranged linearly on one electrode. A connection structure was produced in the same manner as in Example 4 except that an insulating film having a total of 120 openings (total opening area 12000 μm ² ) was formed.

(Example 7)
The size of the opening of the insulating film of the first connection target member is a square having a length of 30 μm and a width of 30 μm, and 20 pieces in the length direction and one piece in the width direction are arranged linearly on one electrode. A connection structure was fabricated in the same manner as in Example 1 except that an insulating film having a total of 20 openings (total opening area of 18000 μm ² ) was formed.

(Example 8)
In the same manner as in Example 1 except that the thickness of the insulating film of the first connection target member is changed to 450 nm and the angle formed by the inner peripheral surface of the opening of the insulating film and the lower surface of the insulating film is changed to 65 °. A connection structure was produced.

Example 9
(1) Preparation of anisotropic conductive paste An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the composition of the anisotropic conductive paste was changed as shown in Table 1 below.

(2) Production of connection structure Semiconductor chip (chip size is 15.1 mm × 1.6 mm, thickness is 300 μm, and 726 protruding electrodes having a length of 100 μm, a width of 20 μm, and a pitch of 30 μm are formed on the periphery of the chip ( A second connection target member) was prepared.

  Electrodes having a length of 120 μm, a width of 20 μm, and a pitch of 30 μm were formed on a glass substrate having a thickness of 0.7 mm so as to have the same pattern as the electrode pattern of the semiconductor chip. The electrode was formed to have a thickness of Ti / Al / Ti = 15/180/50 nm from the glass side.

  After forming the electrode, the entire surface was covered with SiN to form an insulating film having a thickness of 900 nm.

The insulating film on the upper surface of the electrode was opened by dry etching using a photomask in a length of 10 μm and a width of 10 μm in one row in the electrode width direction and in five rows in the length direction. In this way, the opening size is a square having a length of 10 μm and a width of 10 μm, and a total of five openings are arranged on a single electrode in a straight line with five in the length direction and one in the width direction. An insulating film having a total opening area of 500 μm ² was formed. As a result of cross-sectional observation of the insulating film in the periphery of the opening, the angle α formed by the inner peripheral surface of the opening of the insulating film and the lower surface of the insulating film was 40 °.

  Further, an ITO film having a thickness of 55 nm was formed, and the other part of the ITO film was removed by etching so that only the opening on the upper surface of the electrode (opening of the insulating film) and the SiN portion on the upper surface of the electrode remained. Thus, a first connection target member was obtained. The surface roughness Ra of the ITO film was 20 nm.

  A connection was made in the same manner as in Example 1 except that the obtained anisotropic conductive paste was applied onto the obtained first connection target member and the prepared second connection target member was used. A structure was produced.

(Example 10)
Except that the thickness of the insulating film formed on the semiconductor chip was changed to 450 nm and the angle α formed between the inner peripheral surface of the opening of the insulating film and the lower surface of the insulating film was changed to 60 °, the same as in Example 9 A connection structure was produced.

(Example 11)
An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the composition of the anisotropic conductive paste was changed as shown in Table 1 below. A connection structure was produced in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 12)
An anisotropic conductive paste was obtained in the same manner as in Example 1 except that the composition of the anisotropic conductive paste was changed as shown in Table 1 below. A connection structure was produced in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Comparative Example 1)
A connection structure was fabricated in the same manner as in Example 1 except that the insulating film was not formed on the plurality of electrodes.

(Evaluation)
(1) Viscosity of anisotropic conductive paste (anisotropic conductive material) at room temperature E-type viscosity measuring device (manufactured by TOKI SANGYO CO. LTD, trade name: VISCOMETER TV-22, rotor used: φ15 mm, temperature: 25 C.), the viscosity η1 (10 rpm) of the anisotropic conductive paste at 10 rpm and 25 ° C. was measured. Similarly, the viscosity η1 (1 rpm) under the condition of 1 rpm was measured to determine the viscosity ratio (η1 (1 rpm) / η1 (10 rpm)).

(2) Minimum melt viscosity η2 and viscosity ratio (η2 / η3) of the B-staged anisotropic conductive material
Using a rheometer (“STRESSTECH” manufactured by EOLOGICA), measurement conditions: strain control 1 rad, frequency 1 Hz, temperature rising rate 20 ° C./min, measurement temperature range 60 to 150 ° C. The temperature indicating the minimum melt viscosity η2 and the minimum melt viscosity of the staged anisotropic conductive material layer was measured. Further, the viscosity was measured in the same manner as described above except that the frequency was set to 10 Hz, the minimum melt viscosity η3 at the temperature showing the minimum melt viscosity was measured, and the viscosity ratio (η2 / η3) was obtained.

(3) Elastic modulus at 25 ° C. and glass transition temperature Tg of the cured layer obtained by curing the anisotropic conductive paste (anisotropic conductive material)
The elastic layer at 25 ° C. and the glass transition temperature Tg of the cured layer obtained by curing the anisotropic conductive material layer in the connection structure were prepared by preparing a sample having a width of 3 mm × length of 15 mm × thickness of 0.1 mm, and measuring viscoelasticity. Using a machine DVA-200 (manufactured by IT Measurement & Control Co., Ltd.), the temperature was increased at a rate of 5 ° C./min, with a deformation rate of 0.1% and 10 Hz. The temperature at the peak of tan δ was defined as Tg (glass transition temperature).

(4) Presence / absence of voids in the cured product layer of the connection structure In the obtained connection structure, whether or not voids were generated in the cured product layer obtained by curing the anisotropic conductive material layer was observed with an optical microscope. The presence or absence of voids was determined according to the following criteria. If there are no voids, the connection reliability increases, and the fewer the voids, the higher the connection reliability.

[Criteria for the presence or absence of voids]
○: No void △: There is a slight void, but there is no void larger than the electrode L / S, pitch ×: There is a void larger than the size between adjacent electrodes

(5) 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 ×: 9 or less particles between each electrode

(6) Conductivity The resistance values at 20 points of the obtained connection structure were evaluated by a four-terminal method. Conductivity (conductivity reliability) was determined according to the following criteria.

[Conductivity criteria]
○: 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.

(7) Insulating property It was measured with a tester whether or not a leak occurred in 20 adjacent electrodes of the obtained connection structure. Insulation was judged according to the following criteria.

[Insulation criteria]
○: No leak point ×: Leak point

(8) Connection reliability when subjected to thermal history 100 obtained connection structures are held at −30 ° C. for 5 minutes, then heated to 120 ° C. in 25 minutes, and held at 120 ° C. for 5 minutes. After that, a cold cycle test was performed in which the process of lowering the temperature to -30 ° 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, “◯” indicates that the number of defective conductions is 1 or less, “Δ” indicates that the number is 2 or more, and 3 or less. X ”was determined.

(9) Moisture and heat resistance test The 15 connected structures obtained were allowed to stand for 1000 hours under the conditions of 85 ° C and 85% RH, and then the conductivity was evaluated in the same manner. The case where the result in the continuity determination criterion (6) was “◯” was determined as “◯”, and the case where the result in the continuity determination criterion was “×” was determined as “X”.

  The results are shown in Table 1 below.

DESCRIPTION OF SYMBOLS 1 ... Connection structure 2 ... 1st connection object member 2a ... Surface 2b ... 1st electrode 2c ... Insulating film 3 ... Hardened | cured material layer 3a ... Surface 3A ... Anisotropic conductive material layer 3B ... Different in B stage Isotropic conductive material layer 4 ... second connection target member 4a ... surface 4b ... second electrode 5 ... conductive particles X ... opening

Claims (9)

A first connection target member having a first electrode and an insulating film covering the first electrode and having a plurality of openings so as to partially expose the first electrode is used. And using an anisotropic conductive material containing a curable component and conductive particles, the different electrode so as to cover the first electrode and the insulating film on the surface of the first connection target member. Laminating an anisotropic conductive material layer with an isotropic conductive material;
On the surface opposite to the first connection target member side of the anisotropic conductive material layer, a second connection target member having a second electrode on the surface, the first electrode and the second connection Laminating the electrodes facing each other;
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 manufacturing method of a connection structure using the anisotropic conductive material whose minimum melt viscosity in 60-150 degreeC is 1000 Pa.s or more and 10000 Pa.s or less as said anisotropic conductive material.   The method for manufacturing a connection structure according to claim 1, wherein the aspect ratio of the first electrode is 10 or more. The first electrode has a length direction and a width direction;
The insulating film has two or more openings arranged at a distance in the length direction of the first electrode, or the insulating film is spaced at a distance in the width direction of the first electrode. The manufacturing method of the connection structure of Claim 1 or 2 which has two or more of the said arrangement | positioning openings.   The total opening area of the plurality of openings of the insulating film on the first electrode is 3/10 or more of the upper area of the first electrode. Method for manufacturing the connection structure of the present invention.   The average value of the opening diameter per one of the plurality of openings of the insulating film on the first electrode is 1.5 times or more and 15 times or less of the average particle diameter of the conductive particles. The manufacturing method of the connection structure of any one of 1-4. At least one of the first and second connection target members is a semiconductor chip,
The manufacturing method of the connection structure of any one of Claims 1-5 whose upper area of a 1st electrode is 500 micrometers- ² or less.   The manufacturing method of the connection structure of any one of Claims 1-6 whose thickness of the said insulating film is 50 nm or more and 2 micrometers or less.   The manufacturing method of the connection structure of any one of Claims 1-7 which uses a paste-form anisotropic conductive paste as the said anisotropic conductive material. As the anisotropic conductive material, using a paste-like anisotropic conductive paste curable by light irradiation and heating,
When the anisotropic conductive material layer is cured, the anisotropic conductive material layer is irradiated with light to advance the curing to form a B-stage anisotropic conductive material layer, and then the B stage The manufacturing method of the connection structure of any one of Claims 1-8 which heat-harden the anisotropic anisotropic conductive material layer, and make it harden | cure, and form the said hardened | cured material layer.

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