KR20160125343A - Connection structure manufacturing method - Google Patents

Abstract

Provided is a method of manufacturing a connection structure capable of efficiently disposing solder particles on an electrode and improving reliability of conduction between electrodes. A method of manufacturing a connection structure according to the present invention includes the steps of disposing a conductive paste containing a plurality of solder particles and a thermosetting component on a surface of a first connection target member, Placing the second connection target member so that the first electrode and the second electrode face each other on a surface opposite to the first connection target member and the second connection target member, Wherein the step of forming the connecting member and the step of forming the connecting portion are carried out without applying pressure to the conductive paste, 2 The weight of the member to be connected is applied.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing a connection structure,

The present invention relates to a method of manufacturing a connection structure in which electrodes are electrically connected by solder particles.

Anisotropic conductive paste such as anisotropic conductive paste and anisotropic conductive film are widely known. In the anisotropic conductive material, the conductive particles are dispersed in the binder resin.

The anisotropic conductive material can be used for various connection structures, for example, connection (FOG (Film on Glass)) between a flexible printed board and a glass substrate, connection (COF (Chip on Film)) between a semiconductor chip and a flexible printed board, (COG (Chip on Glass)) between a semiconductor chip and a glass substrate and connection (FOB (Film on Board)) between a flexible printed substrate and a glass epoxy substrate.

When the electrodes of the flexible printed circuit board and the electrodes of the glass epoxy substrate are electrically connected by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass epoxy substrate. Subsequently, the flexible printed circuit board is laminated and heated and pressed. Thereby, the anisotropic conductive material is cured, and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

As an example of the anisotropic conductive material, there is disclosed an adhesive tape comprising a resin layer containing a thermosetting resin, a solder component and a curing agent, wherein the solder component and the curing agent are present in the resin layer . The adhesive tape is in the form of a film, not a paste.

Further, Patent Document 1 discloses a bonding method using the adhesive tape. Specifically, the first substrate, the adhesive tape, the second substrate, the adhesive tape and the third substrate are laminated in this order from the bottom to obtain a laminate. At this time, the first electrode provided on the surface of the first substrate and the second electrode provided on the surface of the second substrate are opposed to each other. The second electrode provided on the surface of the second substrate is opposed to the third electrode provided on the surface of the third substrate. Then, the laminate is heated and bonded at a predetermined temperature. Thus, a connection structure is obtained.

In Patent Document 1, it is described that the solder powder is pressed at a predetermined pressure at the time of bonding in order to move the solder powder through the surface of the electrode so as to efficiently move the solder powder. For example, not less than 0 MPa, preferably not less than 1 MPa, and even if the pressure intentionally applied to the adhesive tape is 0 MPa, even if the adhesive tape is fixed to the adhesive tape by the self weight of the member disposed on the adhesive tape It is also possible to apply a pressure of a predetermined pressure to the pressure-sensitive adhesive layer.

WO2008 / 023452A1

The adhesive tape described in Patent Document 1 is in the form of a film, not a paste. As a result, it is difficult to efficiently dispose the solder powder on the electrode (line). For example, in the adhesive tape described in Patent Document 1, a part of the solder powder is likely to be disposed in an area (space) where no electrode is formed. The solder powder disposed in the region where no electrode is formed does not contribute to the conduction between the electrodes.

In Patent Document 1, it is described that the pressure to be intentionally applied to the adhesive tape may be 0 MPa. However, there is no description about the difference in effect between the case where the pressure exceeding 0 MPa is given and the case where the pressure is 0 MPa .

An object of the present invention is to provide a method of manufacturing a connection structure capable of efficiently disposing solder particles on an electrode and improving reliability of conduction between electrodes.

According to a broad aspect of the present invention, by using a plurality of solder particles and a conductive paste containing a thermosetting component, the conductive paste is placed on the surface of the first connection target member having at least one first electrode on its surface And a second connection target member having at least one second electrode on its surface on a surface opposite to the first connection target member side of the conductive paste, And a connecting portion connecting the first connection target member and the second connection target member by heating the conductive paste at a temperature equal to or higher than the melting point of the solder particles and not more than a curing temperature of the thermosetting component, And a step of forming the second connection target member by the conductive paste, wherein the step of disposing the second connection target member and the step of forming the connection portion Standing, without performing the pressurization, the conductive paste, a manufacturing method of the second connection object member, which connecting element is provided in the weight is applied.

In a specific aspect of the method of manufacturing a connection structure according to the present invention, the second connection target member is a resin film, a flexible printed substrate, a flexible flat cable, or a rigid flexible substrate.

In a specific aspect of the method for manufacturing a connection structure according to the present invention, the distance between the first electrode and the second electrode at a position where the first electrode and the second electrode face each other is 3 占 퐉 or more and 40 占 퐉 or less.

In a specific aspect of the method for manufacturing a connection structure according to the present invention, in the connecting portion, the size of a portion where the first electrode and the second electrode face each other is set such that the first electrode and the second electrode face each other And not more than 40 times the size of the non-existent portion.

In a specific aspect of the conductive paste according to the present invention, the viscosity at 25 캜 is not less than 10 Pa · s and not more than 800 Pa · s.

In a specific aspect of the conductive paste according to the present invention, the lowest value of the viscosity in the temperature range below the melting point of the solder particles is 0.1 Pa · s or more and 10 Pa · s or less.

In a specific aspect of the method for manufacturing a connection structure according to the present invention, the connection portion has a corner portion, and the first connection object member has, as the first electrode, a first electrode for alignment on the inside of the corner portion And the second connection target member has the second electrode as the second electrode and the second electrode for alignment in the inside of the corner portion, the first electrode for alignment and the second electrode for alignment, And the shortest distance from the tip of the edge portion is 75 占 퐉 or more and 3000 占 퐉 or less.

In a specific aspect of the method of manufacturing a connection structure according to the present invention, the first connection target member has a plurality of first main electrodes having the longitudinal direction and the width direction as the first electrodes, Wherein the member has a plurality of second main electrodes having a longitudinal direction and a width direction as the second electrodes, wherein the linear expansion rate of the first connection target member in the longitudinal direction and the width direction of the first main electrode, C (ppm / 占 폚) of the linear expansion coefficient of the second connection target member in the longitudinal direction and the width direction of the two main electrodes is T (占 폚), and the heating temperature of the conductive paste at the time of forming the connection portion is T And a dimension in a width direction of each of the plurality of first main electrodes is defined as Ya (mm), and a dimension in a width direction of each of the plurality of first main electrodes is defined as Ya ) Satisfies the formula: C 占 T / 1000000 占 Yt <0.5 占 Ya.

A method of manufacturing a connection structure according to the present invention is a method of manufacturing a connection structure using a plurality of solder particles and a conductive paste containing a thermosetting component to form on the surface of a first connection object member having at least one first electrode on a surface thereof, And a second connection target member having at least one second electrode on its surface on a surface opposite to the first connection target member side of the conductive paste, The method comprising the steps of: disposing the conductive paste so that two electrodes are opposed to each other; and heating the conductive paste to a temperature equal to or higher than the melting point of the solder particles and a curing temperature of the thermosetting component, The step of forming the second connection target member and the step of forming the connection portion Since the weight of the second connection target member is applied to the conductive paste without pressurization, the solder particles can be efficiently arranged on the electrode, and the reliability of the conduction between the electrodes can be improved.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a partially cut-away front sectional view schematically showing a connection structure obtained by a method of manufacturing a connection structure according to an embodiment of the present invention; FIG.
2 (a) to 2 (c) are cross-sectional views for explaining respective steps of a method of manufacturing a connection structure according to an embodiment of the present invention.
Fig. 3 (a) is a plan view showing a modified example of the connection structure, and Fig. 3 (b) is a sectional view along the line II in Fig. 3 (a).
4 (a) is a plan view showing a modification of the connection structure, FIG. 4 (b) is a cross-sectional view along II line in FIG. 4 11 is a cross-sectional view taken along line II-II of Fig.
Fig. 5A is a plan view showing a modification of the connection structure, and Fig. 5B is a cross-sectional view taken along the line II in Fig. 5A.
6 is a partial cutaway front sectional view showing a modification of the connection structure.
Figs. 7A, 7B and 7C are images showing an example of the connection structure included in the embodiment of the present invention, Figs. 7A and 7B are sectional views, (C) is a planar image.
Figs. 8A, 8B and 8C are images showing an example of a connection structure not included in the embodiment of the present invention, Figs. 8A and 8B are sectional views, 8 (c) is a planar image.

Hereinafter, the details of the present invention will be described.

In the method for manufacturing a connection structure according to the present invention, a conductive paste, a first connection object member, and a second connection object member are used. The conductive material used in the method of manufacturing a connection structure according to the present invention is not a conductive film but a conductive paste. The conductive paste includes a plurality of solder particles and a thermosetting component. The first connection target member has at least one first electrode on its surface. The second connection object member has at least one second electrode on its surface.

The method for manufacturing a connection structure according to the present invention includes the steps of disposing the conductive paste on the surface of the first connection target member and forming a conductive paste on the surface of the conductive paste opposite to the first connection object side, A step of disposing the second connection target member so that the first electrode and the second electrode are opposed to each other; and heating the conductive paste to a temperature equal to or higher than a melting point of the solder particles and a curing temperature of the thermosetting component, And forming a connection portion connecting the connection target member and the second connection target member by the conductive paste. In the method for manufacturing a connection structure according to the present invention, in the step of disposing the second connection target member and the step of forming the connection portion, the weight of the second connection target member is Is applied. In the method of manufacturing a connection structure according to the present invention, in the step of disposing the second connection target member and the step of forming the connection portion, the conductive paste is subjected to a pressing force exceeding the force of the weight of the second connection object member Is not applied.

In the method of manufacturing a connection structure according to the present invention, since the above-described structure is employed, a plurality of solder particles are easily collected between the first electrode and the second electrode, and a plurality of solder particles are efficiently arranged can do. In addition, a part of the plurality of solder particles is hardly arranged in a region (space) where no electrode is formed, and the amount of solder particles arranged in an area where no electrode is formed can be considerably reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. In addition, it is possible to prevent electrical connection between adjacent electrodes in the lateral direction which should not be connected, and the insulation reliability can be improved.

As described above, in order to efficiently arrange a plurality of solder particles on the electrode and considerably reduce the amount of the solder particles disposed in the region where no electrode is formed, it is necessary to use a conductive paste instead of a conductive film , The present inventors discovered. In the step of disposing the second connection target member and the step of forming the connection portion, if the weight of the second connection target member is applied to the conductive paste without applying pressure, The solder particles arranged in the regions (spaces) where no solder particles are formed are more likely to gather between the first electrode and the second electrode, so that a plurality of solder particles can be efficiently arranged on the electrodes (lines) The present inventors have found. In the present invention, a configuration in which a conductive paste is used instead of a conductive film and a configuration in which the weight of the second connection target member is added to the conductive paste without applying pressure is employed in combination, There is a big meaning because it gets the effect of.

If the conductive paste is used instead of the conductive film, the thickness of the connection portion can be appropriately adjusted by the application amount of the conductive paste. On the other hand, in the case of the conductive film, in order to change or adjust the thickness of the connection portion, there is a problem that a conductive film having a different thickness is prepared or a conductive film having a predetermined thickness is prepared.

Best Mode for Carrying Out the Invention Hereinafter, the present invention will be clarified by explaining specific embodiments and examples of the present invention with reference to the drawings.

First, Fig. 1 schematically shows a partially cut away front cross-sectional view of a connection structure obtained by a method of manufacturing a connection structure according to an embodiment of the present invention.

The connection structure 1 shown in Fig. 1 has a structure in which a first connection target member 2, a second connection target member 3 and a first connection target member 2 and a second connection target member 3 are connected (Not shown). The connecting portion 4 is formed by a plurality of solder particles and a conductive paste containing a thermosetting component. The connecting portion 4 has a soldering portion 4A in which a plurality of solder particles are gathered and joined together and a cured portion 4B in which a thermosetting component is thermally cured.

The first connection target member 2 has a plurality of first electrodes 2a on its surface (upper surface). The second connection target member 3 has a plurality of second electrodes 3a on its surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by the solder portion 4A. Therefore, the first connection target member 2 and the second connection target member 3 are electrically connected by the soldering portion 4A. In the region (cured portion 4B) different from the soldering portion 4A gathered between the first electrode 2a and the second electrode 3a in the connecting portion 4, there is no solder. There is no solder spaced apart from the soldering portion 4A in the region different from the soldering portion 4A (portion of the cured portion 4B). In the case of a small amount, the solder portion 4A gathered between the first electrode 2a and the second electrode 3a may have solder in a different region (cured portion 4B).

As shown in Fig. 1, in the connection structure 1, after the plurality of solder particles are melted, the melts of the solder particles are solidified after the surface of the electrode is widened, and the solder portion 4A is formed. As a result, the connection area between the solder portion 4A and the first electrode 2a, the solder portion 4A, and the second electrode 3a is increased. In other words, by using the solder particles, the solder portion 4A, the first electrode 2a, the solder portion 4A, and the solder portion 4A can be formed in the same manner as in the case of using conductive particles whose conductive outer surface is a metal such as nickel, The contact area of the second electrode 3a becomes large. As a result, conduction reliability and connection reliability in the connection structure 1 are enhanced. The conductive paste may also contain flux. When a flux is used, the flux generally gradually deactivates by heating.

In the connection structure 1 shown in Fig. 1, all of the soldering portions 4A are located in the regions where the first and second electrodes 2a and 3a face each other. The connection structure 1X of the modified example shown in Fig. 6 is different from the connection structure 1 shown in Fig. 1 only in the connection portion 4X. The connecting portion 4X has a soldering portion 4XA and a cured portion 4XB. Most of the soldering portion 4XA is located in the region where the first and second electrodes 2a and 3a face each other and the soldering portion 4XA is part of the first and second electrodes 2a and 3a, But may be sideways from the opposed regions of the electrodes 2a and 3a. The soldering portion 4XA which is laterally protruded from the opposing region of the first and second electrodes 2a and 3a is part of the soldering portion 4XA and is not solder spaced apart from the soldering portion 4XA . Although the amount of solder spaced from the solder portion can be reduced in this embodiment, solder spaced apart from the solder portion may be present in the hardened portion.

When the usage amount of the solder particles is reduced, it is easy to obtain the connection structure 1. If the amount of solder particles used is increased, it is easy to obtain the connection structure 1X.

Next, a method for manufacturing a connection structure according to an embodiment of the present invention for obtaining the connection structure 1 shown in Fig. 1 will be described.

First, a first connection target member 2 having a first electrode 2a on its surface (upper surface) is prepared. 2 (a), a conductive paste 11 containing a plurality of solder particles 11A and a thermosetting component 11B is placed on the surface of the first connection target member 2 (First step). The conductive paste 11 is disposed on the surface of the first connection target member 2 on which the first electrode 2a is provided. After the conductive paste 11 is disposed, the solder particles 11A are arranged on both the first electrode 2a (line) and the region where the first electrode 2a is not formed (space).

The method of disposing the conductive paste 11 is not particularly limited, and examples thereof include coating with a dispenser, screen printing, and ejection with an inkjet apparatus.

Furthermore, a second connection target member 3 having a second electrode 3a on its surface (lower surface) is prepared. 2 (b), in the conductive paste 11 on the surface of the first connection target member 2, the conductive paste 11 is separated from the first connection target member 2 side And the second connection target member 3 is arranged on the surface on the opposite side (second step). The second connection target member 3 is arranged on the surface of the conductive paste 11 from the second electrode 3a side. At this time, the first electrode 2a and the second electrode 3a are opposed to each other.

Subsequently, the conductive paste 11 is heated to a temperature not lower than the melting point of the solder particles 11A and not lower than the hardening temperature of the thermosetting component 11B (third step). That is, the conductive paste 11 is heated at a temperature lower than the melting point of the solder particles 11A and the curing temperature of the thermosetting component 11B. During this heating, the solder particles 11A existing in the region where no electrode is formed are gathered between the first electrode 2a and the second electrode 3a (magnetic cohesion effect). In this embodiment, since the conductive paste is used instead of the conductive film, the solder particles 11A are effectively gathered between the first electrode 2a and the second electrode 3a. Further, the solder particles 11A are melted and bonded to each other. Further, the thermosetting component 11B is thermally cured. As a result, as shown in Fig. 2C, the connecting portion 4 connecting the first connection target member 2 and the second connection target member 3 is formed by the conductive paste 11 do. The connecting portion 4 is formed by the conductive paste 11 and the solder portion 4A is formed by bonding a plurality of solder particles 11A to thermally cure the thermosetting component 11B, . When the solder particles 11A move quickly, the movement of the solder particles 11A which are not located between the first electrode 2a and the second electrode 3a starts, and then the first electrode 2a and the second electrode 3a, It is not necessary to keep the temperature constant until the movement of the solder particles 11A is completed between the solder balls 3a.

In addition, a preliminary heating process may be provided throughout the third process. This preliminary heating step is a step of heating the conductive paste 11 at a temperature at which the weight of the second connection target member 3 is applied and the temperature at which the thermosetting component 11B is not thermally cured at a temperature higher than the melting temperature of the solder Quot; means a step of heating for 60 seconds to 60 seconds. By providing this step, the action to be collected between the first electrode and the second electrode of the solder particles is further enhanced, and the voids that may occur between the first connection object member and the second connection object member can be suppressed have.

In the present embodiment, no pressure is applied in the second step and the third step. In the present embodiment, the weight of the second connection target member 3 is applied to the conductive paste 11. This allows the solder particles 11A to effectively gather between the first electrode 2a and the second electrode 3a at the time of forming the connection portion 4. In addition, when the pressurization is performed in at least one of the second step and the third step, the action of the solder particles to collect between the first electrode and the second electrode is inhibited. This was discovered by the present inventors.

In this manner, the connection structure 1 shown in Fig. 1 is obtained. Further, the second step and the third step may be performed continuously. After the second step is performed, the resulting laminate of the first connection target member 2, the conductive paste 11, and the second connection target member 3 is moved to the heating portion, and the third step is performed It is possible. In order to perform the heating, the laminate may be disposed on the heating member, or the laminate may be disposed in the heated space.

The connection structures 1 and 1X are provided with the first electrode 2a and the second electrode 3a in the stacking direction of the first electrode 2a and the connection portion 4 and the second electrode 3a, (50% or more of the area 100% of the mutually facing portions of the first electrode 2a and the second electrode 3a) of the soldering portion (4A, 4B) in the connecting portions 4, 4A, and 4XA are disposed on the connection structure 1, 1X.

The heating temperature in the third step is not particularly limited as long as it is not lower than the melting point of the solder particles and is not lower than the hardening temperature of the thermosetting component. The heating temperature is preferably 130 占 폚 or higher, more preferably 160 占 폚 or higher, preferably 450 占 폚 or lower, more preferably 250 占 폚 or lower, further preferably 200 占 폚 or lower.

The temperature of the preliminary heating step is preferably 100 占 폚 or higher, more preferably 120 占 폚 or higher, further preferably 140 占 폚 or higher, preferably 160 占 폚 or lower, more preferably 150 占 폚 or lower.

The first connection target member may have at least one first electrode. It is preferable that the first connection target member has a plurality of first electrodes. The second connection target member may have at least one second electrode. The second connection target member preferably has a plurality of second electrodes.

The first and second connection target members are not particularly limited. Specific examples of the first and second connection target members include electronic parts such as a semiconductor chip, a capacitor and a diode, and a resin film, a printed board, a flexible printed board, a flexible flat cable, a rigid flexible board, a glass epoxy board and a glass And electronic parts such as circuit boards such as boards. It is preferable that the first and second connection target members are electronic parts.

It is preferable that at least one of the first connection target member and the second connection target member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. It is preferable that the second connection target member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. The resin film, the flexible printed circuit board, the flexible flat cable, and the rigid flexible substrate have high flexibility and relatively light weight properties. In the case of using a conductive film for connection of such members to be connected, there is a tendency that the solder particles are difficult to collect on the electrode. On the other hand, in the present invention, since conductive paste is used, even if a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate is used, the solder particles can be efficiently collected on the electrode, Can be increased sufficiently. In the case of using a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate, the effect of improving the conduction reliability between the electrodes by not pressing is further improved compared with the case of using other members to be connected such as semiconductor chips . The first and second connection target members may be a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate.

Examples of the electrode provided on the member to be connected include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a silver electrode, a molybdenum electrode, a SUS electrode, and a tungsten electrode. When the connection target member is a flexible printed circuit board or a flexible flat cable, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode, or a copper electrode. When the connection target member is a glass substrate, it is preferable that the electrode is an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, or a tungsten electrode. When the electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of the metal oxide layer. Examples of the material of the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al and Ga.

The distance D1 of the connecting portion at a position where the first electrode and the second electrode face each other is preferably at least 3 mu m, more preferably at least 5 mu m, preferably at most 40 mu m, more preferably at least 30 mu m Or less. If the distance D1 is equal to or lower than the lower limit, the connection reliability of the connecting portion and the member to be connected becomes further higher. When the distance D1 is less than the upper limit, the solder particles are more likely to gather on the electrode at the time of forming the connection portion, and the reliability of the conduction between the electrodes is further increased. From the viewpoint of further enhancing the conduction reliability between the electrodes, the distance D1 is preferably 10 占 퐉 or more, and more preferably 12 占 퐉 or more.

In the connecting portion, the size S1 (for example, the slits in FIG. 3A and FIG. 4A) of the portion where the first electrode and the second electrode face each other is larger than the size (For example, the point of FIG. 3 (a) and the point of FIG. 4 (a)) of the portion where the second electrode is not opposed to the second electrode, preferably 2 times or more, more preferably 10 times Or more, preferably 40 times or less, and more preferably 30 times or less. The size S1 and the size S2 are the sizes when the connection structure is viewed from a plane. The size S 1 is an area of a region where the first electrode and the second electrode overlap when viewed from the plane of the connection structure. The size S2 is an area of a region where the first electrode and the second electrode are not overlapped when viewed from a plane. The size S2 is a size excluding the size S1 from the size of the whole connecting portion.

Next, modified examples of the connection structure will be described.

3 (a) and 3 (b) show a connection structure 51, which is a modified example. Fig. 3 (a) is a plan view, and Fig. 3 (b) is a sectional view along the line I-I.

As in the connection structure 51 shown in FIGS. 3A and 3B, it is preferable that the connection portion 54 has the edge portion C. 3 (a) and 3 (b), the connecting portion 54 has four corner portions C in the main surface direction. The corner portion C is, for example, a portion where two sides of the connection portion 54 intersect. It is preferable that the first connection target member 52 has the first electrode 52aa for positioning on the inside of the corner portion C as the first electrode 52a. It is preferable that the second connection target member 53 has the second electrode 53aa for positioning on the inside of the corner portion C as the second electrode 53a. When such position alignment electrodes are provided, when the solder particles are gathered and gathered between the first electrode 52aa for alignment and the second electrode 53aa for alignment, the first electrodes for alignment The first electrode 52aa and the second electrode 53aa for position alignment are prevented from being displaced and the generated positional deviation is eliminated (for example, in FIG. 7A of the embodiment of the present invention and FIG. (Difference in Fig. 8 (a) in a form not included in the embodiment). As a result, the reliability of conduction between the electrodes increases.

3 (b), the first electrode 52a and the second electrode 53a are formed of one or more electrodes. The first electrode 52a and the second electrode 53a are preferably electrodes having an array pattern of two or more interdigitated, zigzagged, dot or rectangular electrodes. In this case, it is preferable that the pattern of the first electrode 52a and the pattern of the second electrode 53a coincide with each other. In the case of two or more electrodes, the pitch of the electrodes is preferably 75 占 퐉 or more, more preferably 100 占 퐉 or more, preferably 2 mm or less, and more preferably 1 mm or less. The length of the electrode is preferably 200 占 퐉 or more, more preferably 1 mm or more, preferably 5 mm or less, and more preferably 3 mm or less.

3 (a) and 3 (b), the first connection target member 52 is partially overlapped with the second connection target member 53. As shown in Fig. A first electrode 52a (main electrode) electrically connected to the central region of the overlapping portion of the first connection target member 52 and the second connection target member 53 by the solder portion 54A, And the two electrodes 53a (main electrode) are arranged so as to face each other. 3 (a), two positioning electrodes 52aa and 52b are provided in the vicinity of the two corner portions C of the connection portions 54 corresponding to the two corner portions of the tip end of the second connection subject member 53, And the second positional alignment second electrode 53aa are opposed to each other. The first electrode 52aa for alignment and the second electrode 53aa for alignment are electrically connected by a solder portion 54A. A hardened portion 54B is located around the soldering portion 54A.

The dimensions of the first electrode 52aa and the second electrode 53aa are square of at least 300 mu m, more preferably at least 500 mu m, and the size of the first electrode 52aa and the second electrode 53aa The shape may be a square, a rectangle, a circle, or an ellipse.

The first electrode 52aa and the second electrode 53aa may be used only for alignment or as an electrode for a power supply requiring a large electrode area.

It is preferable that the shortest distance between the first electrode for position alignment and the second electrode for alignment and the tip end of the corner portion is 75 占 퐉 or more and 3000 占 퐉 or less from the viewpoint of further facilitating alignment.

4 (a) and 4 (b) show a connection structure 51X which is a modified example. 4 (a) is a plan view, Fig. 4 (b) is a sectional view along the line I-I, and Fig. 4 (c) is a sectional view along the line II-II.

4 (a) and 4 (b), four corners C of the connection portion 54X corresponding to the two corners of the tip of the second connection subject member 53X and the remaining two corners C Four first alignment electrodes 52aa and four second alignment electrodes 53aa are disposed so as to face each other in the vicinity of the edge portions C of the four corners. As described above, the first and second electrodes 52aa and 53aa for positioning may be disposed in the vicinity of the four corners C, respectively. The first electrode 52aa for alignment and the second electrode 53aa for alignment are electrically connected by solder 54XA. A hardened portion 54XB is located around the soldering portion 54XA.

5 (a) and 5 (b) show a connection structure 51Y which is a modified example. 5 (a) is a plan view, and Fig. 5 (b) is a sectional view along line I-I.

In the connection structure 51Y, positional shifts between the upper and lower electrodes due to thermal expansion during heating of the first connection target material 52Y and the second connection target material 53Y are suppressed, and conduction reliability is further improved The first connection target member 52Y has a plurality of first main electrodes 52ab having a longitudinal direction and a width direction as the first electrode 52a and the second connection target member 53Y has a plurality of first main electrodes 52a, The second electrode 53a has a plurality of second main electrodes 53ab having a longitudinal direction and a width direction and the first connection target member 52Y in the longitudinal direction and the width direction of the first main electrode 52ab, C (ppm / DEG C) between the coefficient of linear expansion of the first main electrode 53A and the linear expansion rate of the second connection target member 53Y in the longitudinal direction and the width direction of the second main electrode 53ab, and when the connection portion 54Y is formed And the dimension of the entire first main electrode 52ab in the width direction of the first main electrode 52ab is set to be T (占 폚) Ct / 1000000 x Yt < 0.5 x Ya, where Yt (mm) is the thickness of the first main electrode 52a and Ya (mm) is the dimension in the width direction of each of the plurality of first main electrodes 52ab Do.

The plurality of first main electrodes 52ab are arranged in parallel in the longitudinal direction with a predetermined space therebetween. The plurality of second main electrodes 53ab are arranged in parallel in the longitudinal direction with a predetermined space.

The first connection target member 52Y has a first electrode 52aa for alignment. The second connection target member 53Y has the second electrode 53aa for alignment. The first main electrode 52ab does not include the first electrode 52aa for alignment. The second main electrode 53ab does not include the second electrode 53aa for alignment.

The first main electrode 52ab and the second main electrode 53ab are electrically connected by a solder portion 54YA. A hardened portion 54YB is located around the soldering portion 54YA.

The coefficient of linear expansion is measured under the condition of a temperature range from 25 DEG C at a heating rate of 5 DEG C / min to a heating temperature of the conductive paste when the connection portion is formed using TMA / SS6100 (manufactured by SII). The coefficient of linear expansion is obtained as an average value in the temperature range.

In order to efficiently arrange the solder particles on the electrode, the viscosity of the conductive paste at 25 캜 is preferably 10 Pa · s or more, more preferably 50 Pa · s or more, further preferably 100 Pa · s or more, Is not more than 800 Pa · s, more preferably not more than 600 Pa · s, even more preferably not more than 500 Pa · s.

The viscosity can be appropriately adjusted depending on the type and blending amount of the compounding ingredients. In addition, the viscosity can be relatively increased by use of a filler.

The viscosity can be measured at 25 캜 and 5 rpm using, for example, an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.).

(The value of the lowest melt viscosity) of the conductive paste in the temperature range of 25 占 폚 or higher and the melting point of the solder particles (solder) or lower is preferably 0.1 Pas or more, more preferably 0.2 Pas Pa · s or more, preferably 10 Pa · s or less, more preferably 1 Pa · s or less. When the lowest value of the viscosity is not less than the lower limit and not more than the upper limit, the solder particles can be arranged more efficiently on the electrode.

The lowest value of the viscosity was measured by using a strain control 1rad, a frequency of 1 Hz, a temperature raising rate of 20 占 폚 / min, a measuring temperature range of 40 to 200 占 폚 (provided that the solder particles The melting point of the solder particles is the upper limit of the temperature when the melting point of the solder particles exceeds 200 DEG C). From the measurement results, the lowest value of the viscosity in the temperature range of the melting point of the solder particle or less is evaluated.

The conductive paste includes a thermosetting component and solder particles. The thermosetting component preferably includes a curing compound (thermosetting compound) that can be cured by heating and a thermosetting agent. The conductive paste preferably includes a flux. The conductive paste preferably includes a filler.

Hereinafter, other details of the present invention will be described.

(Solder particles)

The solder particles have solder on the conductive outer surface. The solder particles are formed by solder on both the center portion and the conductive outer surface.

The solder is preferably a low melting point metal having a melting point of 450 캜 or lower. The solder particles are preferably low melting point metal particles having a melting point of 450 캜 or lower. The low melting point metal particles are particles containing a low melting point metal. The low melting point metal means a metal having a melting point of 450 캜 or lower. The melting point of the low melting point metal is preferably 300 DEG C or lower, more preferably 160 DEG C or lower. Further, the solder particles include tin. The content of tin in 100 wt% of the metal contained in the solder particles is preferably at least 30 wt%, more preferably at least 40 wt%, still more preferably at least 70 wt%, particularly preferably at least 90 wt% . When the content of tin in the solder particles is lower than the lower limit described above, connection reliability between the solder portion and the electrode is further enhanced.

The content of the tin was measured using a high frequency inductively coupled plasma emission spectrochemical analyzer ("ICP-AES" manufactured by Horiba Seisakusho Co., Ltd.) or a fluorescent X-ray analyzer ("EDX-800HS" available from Shimadzu Corporation) It is measurable.

By using the solder particles, the solder is melted and bonded to the electrode, and the solder portion conducts between the electrodes. For example, since the solder portion and the electrode are not in point contact but in surface contact, the connection resistance is lowered. In addition, by using the solder particles, the bonding strength between the solder portion and the electrode is increased. As a result, the solder portion and the electrode are less likely to be peeled off, and the conduction reliability and the connection reliability are effectively increased.

The low melting point metal constituting the solder particles is not particularly limited. The low melting point metal is preferably an alloy containing tin or tin. Examples of the alloy include tin-silver alloy, tin-copper alloy, tin-silver-copper alloy, tin-bismuth alloy, tin-zinc alloy and tin-indium alloy. Among them, it is preferable that the low melting point metal is tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, and a tin-indium alloy from the viewpoint of excellent wettability to electrodes. Tin-bismuth alloy, and tin-indium alloy.

The solder particles are preferably a filler material having a liquidus temperature of 450 DEG C or less based on JIS Z3001: welding terminology. Examples of the composition of the solder particles include metal compositions including zinc, gold, silver, lead, copper, tin, bismuth, indium and the like. Among them, tin-indium based (117 ° C process) or tin-bismuth process (139 ° C process) which is a low melting point and lead-free is preferable. That is, the solder particles preferably contain no lead, and preferably contain tin and indium or contain tin and bismuth.

The solder particles may be at least one selected from the group consisting of nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese, chromium, Molybdenum, palladium, and the like. From the viewpoint of further increasing the bonding strength between the solder portion and the electrode, it is preferable that the solder particles include nickel, copper, antimony, aluminum or zinc. From the viewpoint of further increasing the bonding strength between the solder portion and the electrode, the content of these metals for increasing the bonding strength is preferably 0.0001 wt% or more, and preferably 1 wt% or less, in 100 wt% of the solder particles.

The average particle diameter of the solder particles is preferably 0.5 mu m or more, more preferably 1 mu m or more, further preferably 3 mu m or more, particularly preferably 5 mu m or more, preferably 100 mu m or less, Is not more than 40 mu m, further preferably not more than 30 mu m, more preferably not more than 20 mu m, particularly preferably not more than 15 mu m, and most preferably not more than 10 mu m. When the mean particle diameter of the solder particles is not less than the lower limit and not more than the upper limit, solder particles can be arranged more efficiently on the electrode. It is particularly preferable that the average particle diameter of the solder particles is not less than 3 mu m and not more than 30 mu m.

The &quot; average particle diameter &quot; of the solder particles indicates the number average particle diameter. The average particle diameter of the solder particles is obtained by, for example, observing 50 pieces of arbitrary solder particles with an electron microscope or an optical microscope and calculating an average value.

The content of the solder particles in 100 wt% of the conductive paste is preferably 1 wt% or more, more preferably 2 wt% or more, still more preferably 10 wt% or more, particularly preferably 20 wt% Is not less than 30% by weight, preferably not more than 80% by weight, more preferably not more than 60% by weight, further preferably not more than 50% by weight. If the content of the solder particles is lower than or equal to the lower limit and lower than or equal to the upper limit, solder particles can be more efficiently arranged on the electrode, and more solder particles can be easily arranged between the electrodes, thereby further improving the reliability of conduction. From the viewpoint of further improving conduction reliability, the content of the solder particles is preferably large.

(Compound that can be cured by heating: a thermosetting component)

Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds and polyimide compounds. Among them, an epoxy compound is preferable from the viewpoint of further improving the curability and viscosity of the conductive paste and further improving the connection reliability.

The content of the thermosetting compound in 100 wt% of the conductive paste is preferably 20 wt% or more, more preferably 40 wt% or more, further preferably 50 wt% or more, preferably 99 wt% By weight, preferably not more than 98% by weight, more preferably not more than 90% by weight, particularly preferably not more than 80% by weight. From the viewpoint of further improving the impact resistance, the content of the above-mentioned thermosetting component is preferably large.

(Thermosetting agent: thermosetting component)

The thermosetting agent thermally cures the thermosetting compound. Examples of the heat curing agent include an imidazole curing agent, an amine curing agent, a phenol curing agent, a polythiol curing agent, an acid anhydride, a thermal cationic initiator, and a thermal radical generator. The thermosetting agent may be used alone or in combination of two or more.

Among them, an imidazole curing agent, a polythiol curing agent or an amine curing agent is preferable because the conductive paste can be cured at a lower temperature more rapidly. Further, when the heat curing agent is mixed with the curable compound that can be cured by heating, the storage stability is enhanced, so that a latent curing agent is preferable. The latent curing agent is preferably a latent imidazole curing agent, a latent polythiol curing agent or a latent amine curing agent. Further, the thermosetting agent may be coated with a high molecular substance such as a polyurethane resin or a polyester resin.

The imidazole curing agent is not particularly limited, and examples thereof include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, Imidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')] - ethyl -s- triazine and 2,4- diamino- -Methylimidazolyl- (1 ')] - ethyl-s-triazine isocyanuric acid adduct.

The polythiol curing agent is not particularly limited and includes trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate And the like.

The solubility parameter of the polythiol curing agent is preferably 9.5 or more, and preferably 12 or less. The solubility parameter is calculated by the Fedors method. For example, the solubility parameter of trimethylolpropane tris-3-mercaptopropionate is 9.6 and the solubility parameter of dipentaerythritol hexa-3-mercaptopropionate is 11.4.

The amine curing agent is not particularly limited and includes hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetaspiro [5.5] undecane, bis (4-aminocyclohexyl) methane, metaphenylenediamine, and diaminodiphenylsulfone.

Examples of the thermal cationic curing agent include an iodonium-based cationic curing agent, an oxonium-based cationic curing agent, and a sulfonium-based cationic curing agent. Examples of the iodonium-based cationic curing agent include bis (4-tert-butylphenyl) iodonium hexafluorophosphate and the like. Examples of the oxonium-based cation curing agent include trimethyloxonium tetrafluoroborate and the like. Examples of the sulfonium cation-based curing agent include tri-p-tolylsulfonium hexafluorophosphate and the like.

The heat radical generator is not particularly limited, and examples thereof include an azo compound and an organic peroxide. Examples of the azo compound include azobisisobutyronitrile (AIBN) and the like. Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

The reaction initiation temperature of the thermosetting agent is preferably at least 50 ° C, more preferably at least 70 ° C, more preferably at least 80 ° C, preferably at most 250 ° C, more preferably at most 200 ° C, Is 150 DEG C or less, particularly preferably 140 DEG C or less. If the reaction initiation temperature of the thermosetting agent is not less than the lower limit and not more than the upper limit, the solder particles are more efficiently arranged on the electrode. The reaction initiation temperature of the thermosetting agent is particularly preferably from 80 캜 to 140 캜.

From the viewpoint of more efficiently placing the solder on the electrode, the reaction initiation temperature of the thermosetting agent is preferably lower than the melting point of the solder in the solder particle, more preferably 5 deg. C or more, more preferably 10 deg. C or more And it is more preferable that it is low.

The reaction initiation temperature of the thermosetting agent means the rising temperature of the exothermic peak in DSC.

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 1 part by weight or more, preferably 200 parts by weight or less, more preferably 100 parts by weight or less, based on 100 parts by weight of the thermosetting compound. More preferably 75 parts by weight or less. If the content of the heat curing agent is lower than the lower limit described above, it is easy to sufficiently cure the conductive paste. If the content of the thermosetting agent is less than the upper limit, an excess of the thermosetting agent that is not involved in curing after curing is hardly left, and the heat resistance of the cured product is further increased.

(Flux)

It is preferable that the conductive paste includes a flux. By using the flux, the solder can be arranged more effectively on the electrode. The flux is not particularly limited. As the flux, a flux generally used for solder bonding or the like can be used. Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, a phosphoric acid, a derivative of phosphoric acid, an organic halide, a hydrazine, an organic acid, The flux may be used alone or in combination of two or more.

Examples of the molten salt include ammonium chloride and the like. Examples of the organic acid include lactic acid, citric acid, stearic acid, glutamic acid and glutaric acid. Examples of the papermaking papers include activated papermaking and inactive papermaking. It is preferable that the flux is an organic acid having two or more carboxyl groups, and a feedstock. The flux may be an organic acid having two or more carboxyl groups, or may be tanned. By using an organic acid having two or more carboxyl groups and a papermaking paper, the reliability of conduction between the electrodes is further enhanced.

The above paper is a rosin mainly containing abietic acid. The flux is preferably rosin, more preferably abietic acid. By using this preferable flux, the reliability of conduction between the electrodes is further enhanced.

The melting point of the flux is preferably 50 占 폚 or higher, more preferably 70 占 폚 or higher, even more preferably 80 占 폚 or higher, preferably 200 占 폚 or lower, more preferably 160 占 폚 or lower, even more preferably 150 Lt; 0 &gt; C, more preferably 140 &lt; 0 &gt; C or less. When the melting point of the flux is higher than or equal to the lower limit and lower than or equal to the upper limit, the flux effect is more effectively exhibited, and the solder particles are more efficiently arranged on the electrode. The melting point of the flux is preferably 80 ° C or higher and 190 ° C or lower. The melting point of the flux is particularly preferably from 80 캜 to 140 캜.

Examples of the flux having a melting point of 80 ° C or more and 190 ° C or less include succinic acid having a melting point of 186 ° C, glutaric acid having a melting point of 96 ° C, adipic acid having a melting point of 152 ° C, pimelic acid having a melting point of 104 ° C, 142 占 폚), benzoic acid (melting point 122 占 폚), malic acid (melting point 130 占 폚), and the like.

The boiling point of the flux is preferably 200 ° C or lower.

From the viewpoint of more efficiently placing the solder on the electrode, the melting point of the flux is preferably lower than the melting point of the solder in the solder particle, more preferably 5 deg. C or lower, more preferably 10 deg. desirable.

From the viewpoint of more efficiently placing the solder on the electrode, the melting point of the flux is preferably lower than the reaction initiation temperature of the thermosetting agent, more preferably 5 deg. C or lower, still more preferably 10 deg. C or lower .

The flux may be dispersed in the conductive paste or attached on the surface of the solder particles.

The content of the flux in 100 wt% of the conductive paste is preferably 0.5 wt% or more, preferably 30 wt% or less, more preferably 25 wt% or less. The conductive paste may not contain a flux. If the content of the flux is above the lower limit and below the upper limit, it is difficult to further form an oxide film on the surface of the solder and the electrode, and furthermore, the oxide film formed on the surface of the solder and the electrode can be removed more effectively.

(filler)

It is preferable that the conductive paste includes a filler. The use of the filler can suppress the latent heat expansion of the cured product of the conductive paste. The fillers may be used alone or in combination of two or more.

Examples of the filler include inorganic fillers such as silica, talc, aluminum nitride and alumina. The filler may be an organic filler or an organic-inorganic composite filler. The fillers may be used alone or in combination of two or more.

The conductive paste and the filler each preferably contain an inorganic filler. By using the inorganic filler, the specific gravity of the conductive paste and the thixotropic property can be controlled to a more suitable range, so that the settling of the solder particles is further suppressed, and the reliability of connection of the connection structure is further enhanced.

The conductive paste and the filler each preferably include silica. The silica is a silica filler. By using silica, the specific gravity of the conductive paste and the thixotropic property can be controlled to a more suitable range, so that the settling of the solder particles is further suppressed, and the reliability of the connection structure is further improved.

The content of the filler in 100 wt% of the conductive paste is preferably 2 wt% or more, more preferably 5 wt% or more, preferably 60 wt% or less, and more preferably 50 wt% or less. When the content of the filler is not less than the lower limit and not more than the upper limit, solder particles are more efficiently arranged on the electrode.

(Other components)

The conductive paste may contain various additives such as fillers, extenders, softeners, plasticizers, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents and flame retardants May be included.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. The present invention is not limited to the following examples.

Polymer A:

Synthesis of a reaction product (polymer A) of bisphenol F with 1,6-hexanediol diglycidyl ether and bisphenol F type epoxy resin:

72 parts by weight of bisphenol F (containing 4,4'-methylene bisphenol and 2,4'-methylene bisphenol and 2,2'-methylene bisphenol in a weight ratio of 2: 3: 1), 1,6-hexane diol diglyme , 70 parts by weight of cidyl ether and 30 parts by weight of a bisphenol F type epoxy resin (EPICLON EXA-830CRP, manufactured by DIC) were put in a three-necked flask and dissolved at 150 占 폚 under a nitrogen flow. Thereafter, 0.1 part by weight of tetra-n-butylsulfonium bromide as an addition reaction catalyst between a hydroxyl group and an epoxy group was added and an addition polymerization reaction was carried out at 150 ° C for 6 hours under a nitrogen flow to obtain a reactant (polymer A).

NMR confirmed that the addition polymerization reaction had proceeded and that the reaction product (polymer A) had a structure unit in which the hydroxyl group derived from bisphenol F and the epoxy group of 1,6-hexanediol diglycidyl ether and bisphenol F type epoxy resin were bonded In the main chain, and had epoxy groups at both ends.

The weight average molecular weight of the reactant (polymer A) obtained by GPC was 10,000, and the number average molecular weight was 3,500.

Polymer B: Epoxy rigid skeleton phenoxy resin at both ends, "YX6900BH45" manufactured by Mitsubishi Chemical Corporation, weight average molecular weight of 16,000

Thermosetting compound 1: resorcinol-type epoxy compound, "EX-201" manufactured by Nagase Chemtex Co.,

Thermosetting compound 2: naphthalene type epoxy compound "HP-4032D" manufactured by DIC

Thermosetting compound 3: bisphenol F type epoxy resin, "EVA-830CRP" manufactured by DIC Corporation

Thermal curing agent: pentaerythritol tetrakis (3-mercaptobutyrate), "CALENS MT PE1" manufactured by Showa Denko KK

Flux: glutaric acid, manufactured by Wako Pure Chemical Industries, Ltd.

Latent epoxy thermosetting agent: "Fuji Cure 7000" manufactured by T & K TOKA

Latent heat curing agent: microcapsule type, "HXA-3932HP" manufactured by Asahi Chemical Industries, Ltd.

Solder particles 1 (Sn-58Bi solder particles, melting point 139 占 폚, "DS10-25" manufactured by Mitsui Kinzoku Kogyo Co., Ltd., average particle diameter 10 占 퐉)

Solder particles 2 (Sn-58Bi solder particles, melting point 139 占 폚, "10-25" manufactured by Mitsui Kinzoku Kogyo Co., average particle diameter 20 占 퐉)

Solder particles 3 (Sn-58Bi solder particles, melting point 139 占 폚, DS20-38 made by Mitsui Kinzoku Kogyo Co., average particle diameter 29 占 퐉)

Solder particles 4 (Sn-58Bi solder particles, melting point: 139 占 폚, average particle diameter: 45 占 퐉,

Conductive Particle 1: A copper layer having a thickness of 1 占 퐉 was formed on the surface of the resin particle, and a solder layer (tin: bismuth = 43 wt%: 57 wt%) having a thickness of 3 占 퐉 was formed on the surface of the copper layer Conductive particle

Method of Making Conductive Particle 1:

Divinylbenzene resin particles (Micro Pearl SP-210, manufactured by Sekisui Chemical Co., Ltd.) having an average particle diameter of 10 占 퐉 were electroless nickel plated to form an underlying nickel plated layer having a thickness of 0.1 占 퐉 on the surface of the resin particles. Subsequently, resin particles having a base nickel plated layer formed thereon were electroplated with copper to form a copper layer having a thickness of 1 탆. Further, electrolytic plating was performed using an electrolytic plating solution containing tin and bismuth to form a solder layer having a thickness of 3 占 퐉. Thus, a 1 mu m-thick copper layer was formed on the surface of the resin particles, and a solder layer (tin: bismuth = 43 wt%: 57 wt%) having a thickness of 3 mu m was formed on the surface of the copper layer Conductive particles 1 were produced.

Phenoxy resin ("YP-50S" manufactured by Shinnitetsu Sumikin Kagaku Co., Ltd.)

(Examples 1 to 4)

(1) Fabrication of anisotropic conductive paste

The components shown in the following Table 1 were compounded in the amounts shown in Table 1 below to obtain an anisotropic conductive paste.

(2) Fabrication of first connection structure (L / S = 50 탆 / 50 탆)

(First connection target member, linear thermal expansion coefficient: 12 ppm / 占 폚 (the first main electrode (first connection member)) having a copper electrode pattern (copper electrode thickness 10 占 퐉) having an L / S of 50 占 퐉 / (The same applies hereinafter) in the longitudinal direction and the width direction). (Second connection target member, coefficient of linear expansion of 16 ppm / 占 폚 (the length direction of the second main electrode and the width of the first main electrode and the second main electrode) having a L / S of 50 占 퐉 / Linear expansion rate in the width direction (the same applies to the following))) was prepared. For the first main electrode, Yt = 10 mm and Ya = 0.05 mm.

The overlapping area of the glass epoxy substrate and the flexible printed circuit board was 1.5 cm x 4 mm, and the number of connected electrodes was 100 paired. A glass epoxy substrate and a flexible printed substrate in which electrodes for positioning (four in total) are located inside the four corners of the connection portion in the obtained first connection structure are used. The shortest distance between the first and second electrodes for position alignment and the tips of the four corners was 500 mu m.

An anisotropic conductive paste immediately after the preparation was coated on the upper surface of the glass epoxy substrate so as to have a thickness of 50 占 퐉 to form an anisotropic conductive paste layer. Subsequently, the flexible printed circuit board was laminated on the upper surface of the anisotropic conductive paste layer such that the electrodes were opposed to each other. At this time, no pressure was applied. The weight of the flexible printed circuit board is applied to the anisotropic conductive paste layer. Thereafter, the solder was melted while heating so that the temperature of the anisotropic conductive paste layer was 185 占 폚, and the anisotropic conductive paste layer was cured at 185 占 폚 to obtain a first connection structure.

(3) Fabrication of second connection structure (L / S = 75 mu m / 75 mu m)

A glass epoxy substrate (FR-4 substrate) having a copper electrode pattern (copper electrode thickness 10 占 퐉) having an L / S of 75 占 퐉 / 75 占 퐉 on the upper surface (first connection target member; linear thermal expansion coefficient: 12 ppm / 占 폚) was prepared. A flexible printed circuit board (second connection target member, linear expansion rate of 16 ppm / 占 폚) having a copper electrode pattern (copper electrode thickness 10 占 퐉) having L / S of 75 占 퐉 / 75 占 퐉 was prepared. For the first main electrode, Yt = 10 mm and Ya = 0.075 mm.

The overlapping area of the glass epoxy substrate and the flexible printed substrate was 1.5 cm x 4 mm, and the number of electrodes connected was 67 paired. A second connection structure was obtained in the same manner as in the production of the first connection structure except that the glass epoxy substrate and the flexible printed substrate differing in L / S were used.

(4) Fabrication of third connection structure (L / S = 100 mu m / 100 mu m)

A glass epoxy substrate (FR-4 substrate) having a copper electrode pattern (copper electrode thickness of 10 占 퐉) having an L / S of 100 占 퐉 / 100 占 퐉 on the upper surface (first connection target member; linear expansion rate: 12 ppm / 占 폚) was prepared. Further, a flexible printed board having a copper electrode pattern (copper electrode thickness 10 占 퐉) having L / S of 100 占 퐉 / 100 占 퐉 was prepared as a flexible printed substrate (second connection target member; coefficient of linear expansion 16 ppm / 占 폚). For the first main electrode, Yt = 10 mm and Ya = 0.1 mm.

The overlapping area of the glass epoxy substrate and the flexible printed board was 1.5 cm x 4 mm, and the number of connected electrodes was 50 paired.

A third connection structure was obtained in the same manner as in the production of the first connection structure except that the glass epoxy substrate and the flexible printed substrate differing in L / S were used.

(Example 5)

A connection structure was obtained in the same manner as in Example 1 except that the number of electrodes of the first connection structure was 75 pairs, the number of electrodes of the second connection structure was 50 pairs, and the number of electrodes of the third connection structure was 38 pairs.

Yt and Ya of the first main electrode are as follows.

First, second and third connection structures: Yt = 7.5 mm

First connection structure: Ya = 0.05 mm

Second connection structure: Ya = 0.075 mm

Third connection structure: Ya = 0.1 mm

(Example 6)

The first, second, and third connection structures were fabricated in the same manner as in Example 1, except that a flexible printed substrate without a position alignment electrode and a glass epoxy substrate without a position alignment electrode were used.

(Example 7)

A rectangular semiconductor chip (thickness: 400 占 퐉) having an electrode size / inter-electrode space of 100 占 퐉 / 100 占 퐉, 75 占 퐉 / 75 占 퐉, 50 占 퐉 / 50 占 퐉 and 5 mm on one side and a glass The first, second and third connection structures were obtained in the same manner as in Example 1 except that an epoxy substrate (size 30 mm x 30 mm thickness 0.4 mm) was used.

(Examples 8 to 11)

The components shown in the following Table 1 were compounded in the amounts shown in Table 1 below to obtain an anisotropic conductive paste. The first, second and third connection structures were obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Comparative Example 1)

The flexible printed circuit board was laminated on the upper surface of the anisotropic conductive paste layer so that the electrodes were opposed to each other, and a pressure of 2 MPa was applied to the flexible printed circuit board, the first, second and third connections Structure was obtained.

(Comparative Example 2)

The first, second and third connection structures were obtained in the same manner as in Example 1 except that a pressure of 2 MPa was applied to the flexible printed circuit board when the anisotropic conductive paste layer was cured.

(Comparative Example 3)

When the flexible printed circuit board is stacked on the upper surface of the anisotropic conductive paste layer so that the electrodes are opposed to each other, a pressure of 2 MPa is applied on the flexible printed circuit board and the flexible printed circuit board is laminated on the upper surface of the anisotropic conductive paste layer, The first, second and third connection structures were obtained in the same manner as in Example 1 except that a pressure of 2 MPa was applied to the flexible printed substrate when the pressure was maintained and the anisotropic conductive paste layer was cured.

(Comparative Example 4)

10 parts by weight of a phenoxy resin ("YP-50S" manufactured by Shinnitetsu Sumikin Chemical Co., Ltd.) was dissolved in methyl ethyl ketone (MEK) so that the solid content became 50% by weight to obtain a dissolution solution. Components other than the phenoxy resin shown in Table 2 below were blended in the amounts shown in Table 2 below and the total amount of the above solution and stirred for 5 minutes at 2000 rpm using a planetary stirrer and dried using a bar coater (Polyethylene terephthalate) film so as to have a thickness of 30 占 퐉. By vacuum drying at room temperature, MEK was removed to obtain an anisotropic conductive film.

The first, second and third connection structures were obtained in the same manner as in Example 1 except that the anisotropic conductive film was used.

(Comparative Example 5)

A rectangular semiconductor chip (thickness: 400 占 퐉) having an electrode size / inter-electrode space of 100 占 퐉 / 100 占 퐉, 75 占 퐉 / 75 占 퐉, 50 占 퐉 / 50 占 퐉 and 5 mm on one side and a glass The same procedure as in Example 7 was carried out except that an epoxy substrate (size 30 mm × 30 mm thickness 0.4 mm) was used and a pressure of 10 MPa was applied at the time of curing the anisotropic conductive paste layer, .

(Comparative Example 6)

The components shown in the following Table 2 were compounded in the amounts shown in Table 2 below to obtain an anisotropic conductive paste. The first, second and third connection structures were obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(evaluation)

(1) Viscosity

The viscosity of the anisotropic conductive paste was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) under the conditions of 25 캜 and 5 rpm.

(2) Minimum melt viscosity

The lowest melt viscosity of the anisotropic conductive paste was measured at a temperature range from 25 占 폚 to the melting point of the solder particles or the melting point of the solder on the surface of the conductive particles.

(3) Distance of connection (distance between electrodes)

The obtained first connection structure was observed by a section to evaluate the distance D1 (interval between the electrodes) of the connection portion at positions where the upper and lower electrodes face each other.

(4) The state of the electrode

The size S1 of the portion where the first and second electrodes face each other and the size S2 of the portion where the first and second electrodes face each other were evaluated from the plan view of the obtained first connection structure. (Size S1 / size S2).

(5) Maximum distance of positional deviation between electrodes

The obtained first, second, and third connection structures were observed in cross section to evaluate the maximum distance between the upper and lower electrode positions.

(6) Arrangement accuracy of solder on electrodes

In the cross-section (cross-section in the direction shown in Fig. 1) of the obtained first, second and third connection structures, the solder remaining in the cured product, spaced apart from the soldering portion disposed between the electrodes, The area (%) was evaluated. In addition, the average of areas in five sections was calculated. The placement accuracy of the solder on the electrode was determined based on the following criteria.

[Criteria for determination of placement accuracy of solder on electrodes]

0: The area of the solder (solder particles) remaining in the cured product separated from the soldering portion disposed between the electrodes of 100% of the total area of the solder shown on the cross section is 0%

A: The area of the solder (solder particles) remaining in the cured product separated from the soldering portion disposed between the electrodes of 100% of the total area of the solder appearing on the cross section is more than 0% and not more than 10%

DELTA: area of solder (solder particles) remaining in the cured product spaced apart from the soldering portion disposed between the electrodes of 100% of the total area of the solder appearing on the cross section exceeds 30%

: Area of solder (solder particles) remaining in the cured product spaced apart from the soldering portion disposed between the electrodes of 100% of the total area of the solder appearing on the cross section exceeds 30%

(7) Reliability of conduction between upper and lower electrodes

In the obtained first, second and third connection structures (n = 15), the connection resistance between the upper and lower electrodes was measured by the four-terminal method. And the average value of the connection resistance was calculated. From the relationship of voltage = current x resistance, the connection resistance can be obtained by measuring the voltage when a constant current is passed. The conduction reliability was judged based on the following criteria.

[Criteria for reliability of conduction]

○○: Average value of connection resistance is 8.0Ω or less

O: Average value of connection resistance exceeds 8.0? 10.0?

?: Average value of connection resistance exceeds 10.0? 15.0?

X: Average value of connection resistance exceeds 15.0?

(8) Insulation reliability between adjacent electrodes

In the obtained first, second and third connection structures (n = 15), after being left for 100 hours in an atmosphere at a temperature of 85 캜 and a humidity of 85%, 5 V was applied between adjacent electrodes, Respectively. The insulation reliability was judged based on the following criteria.

[Judgment Criteria of Insulation Reliability]

○○: Average value of connection resistance is more than 10 ⁷ Ω

○: Average value of connection resistance is 10 ⁶ Ω or more and less than 10 ⁷ Ω

△: average value of connection resistance is 10 ⁵ Ω or more and less than 10 ⁶ Ω

X: Average value of connection resistance is less than 10 ⁵ Ω

The results are shown in Tables 1 and 2 below

From the difference between the results of Examples 1 to 11 and Comparative Examples 1 to 5, it can be seen that the effect of improving conduction reliability is obtained by not performing pressure application.

From the results of Examples 1 to 5, 8 to 11 and Example 6, it can be seen that the positional deviation of the electrodes is suppressed if the electrodes for alignment are present.

From the difference between the results of Example 1 and Comparative Example 1 and the difference between the results of Example 7 and Comparative Example 5, it can be seen that, when the second connection target member is a flexible printed circuit board, , It can be seen that the effect of improving the conduction reliability can be obtained more effectively by not performing the pressurization.

The same was true when a resin film, a flexible flat cable, and a rigid flexible substrate were used in place of the flexible printed substrate.

Further, in the connection structures obtained in Examples 1 to 11, when the mutually facing portions of the first electrode and the second electrode in the lamination direction of the first electrode, the connection portion and the second electrode are observed, The solder portion in the connection portion was disposed at 50% or more of the area 100% of the portions facing each other.

7 (a), (b) and (c) show examples of the connection structure included in the embodiment of the present invention. Figs. 7 (a) and 7 (b) are sectional views, and Fig. 7 (c) is a planar image. 7 (a), 7 (b) and 7 (c), it can be seen that there is no solder (solder particles) remaining in the cured product separated from the soldering portion disposed between the electrodes.

8 (a), 8 (b) and 8 (c) show examples of the connection structure not included in the embodiment of the present invention. The connection structure is a connection structure obtained by applying pressure in the step of disposing the second connection target member. 8 (a) and 8 (b) are sectional views, and FIG. 8 (c) is a planar image. 8 (a), 8 (b) and 8 (c), it is found that a plurality of solder (solder particles) remained in the cured product separated from the soldering portion disposed between the electrodes exists on the side of the soldering portion have. Further, it was confirmed that, in the step of forming the connecting portion, the same connecting structure as that of the connecting structure shown in Figs. 8A, 8B and 8C was obtained even when the pressing was performed.

1, 1X ... Connection structure
2… The first connection object member
2a ... The first electrode
3 ... The second connection object member
3a ... The second electrode
4, 4X ... Connection
4A, 4XA ... Soldering portion
4B, 4XB ... Hardened portion
11 ... Conductive paste
11A ... Solder particles
11B ... Thermosetting component
51, 51X, 51Y ... Connection structure
52, 52X, 52Y ... The first connection object member
52a ... The first electrode
52aa ... The first electrode for position alignment
52ab ... The first main electrode
53, 53X, 53Y ... The second connection object member
53a ... The second electrode
53aa ... The second electrode for position alignment
53ab ... The second main electrode
54, 54X, 54Y ... Connection
54A, 54XA, 54YA ... Soldering portion
54B, 54XB, 54YB ... Hardened portion
C ... Corner portion

Claims (8)

Disposing the conductive paste on a surface of a first connection target member having at least one first electrode on a surface thereof using a plurality of solder particles and a conductive paste containing a thermosetting component;
A second connection target member having at least one second electrode on its surface on a surface opposite to the first connection target member side of the conductive paste is arranged so that the first electrode and the second electrode face each other The process,
A step of forming the connecting portion connecting the first connection target member and the second connection target member by the conductive paste by heating the conductive paste at a temperature equal to or higher than the melting point of the solder particles and not lower than a curing temperature of the thermosetting component And,
Wherein in the step of disposing the second connection target member and the step of forming the connection part, the weight of the second connection target member is applied to the conductive paste without applying pressure. The method of manufacturing a connection structure according to claim 1, wherein the second connection target member is a resin film, a flexible printed board, a flexible flat cable, or a rigid flexible substrate. 3. The method according to claim 1 or 2, wherein the distance of the connecting portion at a position where the first electrode and the second electrode face each other is 3 占 퐉 or more and 40 占 퐉 or less. 4. The display device according to any one of claims 1 to 3, wherein, in the connecting portion, a size of a portion where the first electrode and the second electrode face each other is set such that the first electrode and the second electrode face each other Wherein the size of the portion of the connecting structure is not less than two times but not more than 40 times the size of the portion of the connecting structure. The method for producing a connection structure according to any one of claims 1 to 4, wherein the viscosity at 25 캜 is not less than 10 Pa · s and not more than 800 Pa · s. The method for manufacturing a connection structure according to any one of claims 1 to 5, wherein the minimum value of the viscosity in the temperature range below the melting point of the solder particles is 0.1 Pa · s or more and 10 Pa · s or less. 7. The connector according to any one of claims 1 to 6, wherein the connecting portion has a corner portion,
Wherein the first connection target member has, as the first electrode, a first electrode for positioning on the inside of the corner portion,
The second connection target member has the second electrode as a second electrode for alignment on the inside of the corner portion,
Wherein the shortest distance between the first electrode for position alignment and the second electrode for alignment and the tip end of the corner portion is 75 占 퐉 or more and 3000 占 퐉 or less. The liquid crystal display device according to any one of claims 1 to 7, wherein the first connection target member has a plurality of first main electrodes having the longitudinal direction and the width direction as the first electrodes,
The second connection target member has a plurality of second main electrodes having a longitudinal direction and a width direction as the second electrodes,
The difference between the coefficient of linear expansion of the first connection target member in the longitudinal direction and the width direction of the first main electrode and the coefficient of linear expansion of the second connection target member in the longitudinal direction and the width direction of the second main electrode is C: wherein the heating temperature of the conductive paste at the time of forming the connecting portion is set to T: 占 폚, and a plurality of the first main electrodes in the width direction of the first main electrode have a dimension of Yt: And a dimension in the width direction per one of the plurality of first main electrodes is Ya: mm, the following formula is satisfied: C 占 T / 1000000 占 Yt <0.5 占 Ya.

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