JP2020145145A - Anisotropic conductive sheet - Google Patents

Abstract

To provide an anisotropic conductive sheet provided with an anisotropic conductive portion having excellent anisotropic conductivity while being able to prevent the anisotropic conductive portion from falling off from an insulating layer.SOLUTION: An anisotropic conductive sheet 1 includes an insulating layer 2 having a through hole 6 and an anisotropic conductive portion 3 arranged in the through hole 6. The through hole 6 includes a first opening 60 and a second opening 70. The insulating layer 2 has a third peripheral side surface 43 and an extending surface 7. The anisotropic conductive portion 3 includes a first conductor portion 4 and a second conductor portion 5. The first conductor portion 3 is formed in a substantially flat plate shape. In the first conductor portion 3, a second surface 32 is exposed to the other side in the thickness direction, a peripheral end portion 12 of a first surface 31 is in contact with the insulating layer 2, and the inner portion 11 of the first surface 31 is in contact with the second conductor portion 5. The second conductor portion 5 is in contact with a third peripheral side surface 43. In the second conductor portion 5, a fifth surface 35 is in contact with the inner portion 11 and the extending surface 7, and a fourth surface 34 is exposed to one side in the thickness direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to an anisotropic conductive sheet.

Conventionally, an anisotropic conductive sheet having an insulating layer having a through hole and an anisotropic conductive portion arranged in the through hole and exposed on both sides in the thickness direction is known (see, for example, Patent Document 1 below).

In the anisotropic conductive sheet disclosed in FIG. 11 of Patent Document 1, the anisotropic conductive portion has a conductor portion arranged in the through hole and a second plating layer in contact with one surface in the thickness direction of the conductor portion. Be prepared. Further, the conductor portion integrally has a flat plate-shaped central portion and an inclined portion that inclines to one side in the thickness direction toward the outside from the peripheral edge of the central portion. The outer portion of the inclined portion is covered with an insulating layer and fixed. Further, on one surface in the thickness direction of the conductor portion, the central portion and the inner portion of the inclined portion are in contact with the second plating layer. The second plating layer includes a nickel plating layer.

In Patent Document 1, since the outer portion of the inclined portion is covered with an insulating layer and fixed, the conductor portion is an insulating layer even when a terminal or a probe pressurizes the anisotropic conductive portion from both sides in the thickness direction. Suppress falling out of.

WO2018 / 066541 pamphlet

However, the anisotropic conductive sheet is required to have even better anisotropic conductivity.

However, in the anisotropic conductive sheet described in Patent Document 1, since the second plating layer is formed by electroless plating, there is a limit in increasing the thickness, and therefore, the anisotropic conductive portion is different. There is a problem that the conductivity cannot be sufficiently improved.

The present invention provides an anisotropic conductive sheet having an anisotropic conductive portion having excellent anisotropic conductivity while suppressing the anisotropic conductive portion from falling off from the insulating layer.

In the present invention (1), an insulating layer having a through hole penetrating in the thickness direction and one surface and the other surface which are arranged in the through hole and face each other in the thickness direction are on one side and the other side in the thickness direction, respectively. Each of them is provided with an eccentric conductive portion that is exposed, and the through hole communicates with a first opening portion that is partitioned on the other side portion in the thickness direction and the first opening portion, and is formed on one side portion in the thickness direction. The insulating layer has a second opening to be partitioned, and the insulating layer has a peripheral side surface on the other side for partitioning the other side portion in the thickness direction of the second opening, and a thickness direction from one edge in the thickness direction of the peripheral side surface on the other side. It has an extending surface extending outward in the plane direction orthogonal to the above, and the anisotropic conductive portion includes a first conductor portion arranged in the first opening portion and a second conductor portion arranged in the second opening portion. The first conductor portion is formed in a substantially flat plate shape extending in the surface direction, and in the first conductor portion, the other surface is exposed to the other side in the thickness direction, and the peripheral end portion of one surface is formed. The inner portion that is in contact with the insulating layer and is located inside the peripheral end portion on one surface is in contact with the second conductor portion, and the second conductor portion is in contact with the other peripheral side surface. In the two-conductor portion, the other side thereof comes into contact with the inner side portion and the extending surface, and the one side surface is exposed to one side in the thickness direction.

In this anisotropic conductive sheet, since the first conductor portion is formed in a substantially flat plate shape, it is easy to secure a sufficient thickness, and therefore, the anisotropic conductivity of the anisotropic conductive portion can be reliably improved. ..

Further, the peripheral end portion of the first conductor portion and the portion of the second conductor portion that contacts the extending surface sandwich an insulating layer in the thickness direction. Therefore, it is possible to suppress the anisotropic conductive portion from falling off from the insulating layer.

Therefore, this anisotropic conductive sheet can achieve both the suppression of the anisotropic conductive portion from falling off from the insulating layer and the excellent anisotropic conductivity of the anisotropic conductive portion.

The present invention (2) includes the anisotropic conductive sheet according to (1), wherein the other surface in the thickness direction of the first conductor portion is flush with the other surface in the thickness direction of the insulating layer.

In this anisotropic conductive sheet, the other surface in the thickness direction of the first conductor portion is flush with the other surface in the thickness direction of the insulating layer, so that the other surface in the thickness direction of the anisotropic conductive sheet can be smoothed. it can.

The anisotropic conductive sheet of the present invention can achieve both the suppression of the anisotropic conductive portion from falling off from the insulating layer and the excellent anisotropic conductivity of the anisotropic conductive portion.

FIG. 1 shows a plan view of an embodiment of the anisotropic conductive sheet of the present invention. FIG. 2 shows a cross-sectional view of an embodiment of the anisotropic conductive sheet of the present invention. 3A to 3F are manufacturing process diagrams of the isotropic conductive sheet shown in FIG. 2, FIG. 3A is a process of preparing a base material sheet, FIG. 3B is a process of arranging a first conductor portion, and FIG. 3C. 3D shows a step of arranging the first insulating layer, FIG. 3D shows a step of arranging the second conductor portion, FIG. 3E shows a step of arranging the second insulating layer, and FIG. 3F shows a step of removing the base material sheet. .. FIG. 4 shows a cross-sectional view of a modified example of the anisotropic conductive sheet shown in FIG. 2 (a mode in which the anisotropic conductive portion includes a conductor main body portion and a conductor accessory portion). 5A to 5A are modified examples of the manufacturing process diagram of the anisotropic conductive sheet shown in FIGS. 3A to 3F. FIG. 5A is a step of preparing a base sheet, and FIG. 5B is a first insulating layer. The process of arranging, FIG. 5C is the process of arranging the first conductor portion, FIG. 5D is the process of arranging the second insulating layer, FIG. 5E is the process of arranging the second conductor portion, and FIG. 5F is the third insulation. The step of arranging the layers, FIG. 5G, shows the step of removing the base sheet. FIG. 6 shows a cross-sectional view of a modified example of the anisotropic conductive sheet shown in FIG. 2 (a mode in which the peripheral side surface includes a tapered surface and a vertical surface). FIG. 7 shows a cross-sectional view of a modified example of the anisotropic conductive sheet shown in FIG. 2 (a mode in which the peripheral side surface includes only a vertical surface). FIG. 8 is a cross-sectional view of a modified example of the anisotropic conductive sheet shown in FIG. 2 (a mode in which the first other surface of the first conductor layer is located on the other side in the thickness direction from the second insulating surface of the insulating layer). Shown. FIG. 9 shows a further modification of the anisotropic conductive sheet shown in FIG. 6 (the peripheral side surface includes a tapered surface and a vertical surface, and the first other surface of the first conductor layer is from the insulating second surface of the insulating layer. , A mode located on the other side in the thickness direction) is shown. FIG. 10 shows a further modification of the anisotropic conductive sheet shown in FIG. 6 (the peripheral side surface includes only the vertical surface, and the first other surface of the first conductor layer is thicker than the insulating second surface of the insulating layer. The cross-sectional view of the aspect (aspect located on the other side of the direction) is shown. FIG. 11 shows a cross-sectional view of a modified example of the anisotropic conductive sheet shown in FIG. 2 (a mode in which the peripheral end portion of the second conductor portion is exposed).

<One Embodiment>
An embodiment of the anisotropic conductive sheet of the present invention will be described with reference to FIGS. 1 and 2.

As shown in FIGS. 1 and 2, the anisotropic conductive sheet 1 extends in the plane direction orthogonal to the thickness direction. The anisotropic conductive sheet 1 has one surface and the other surface facing each other in the thickness direction. This anisotropic conductive sheet 1 has conductivity (electrical conductivity) in the thickness direction (anisotropic) in the anisotropic conductive portion 3 to be described next, and conducts semiconductor elements and flexible printed wiring boards, which will be described later. An inspection sheet used for inspection.

The anisotropic conductive sheet 1 includes an insulating layer 2 and a plurality of anisotropic conductive portions 3 arranged on the insulating layer 2. Preferably, the anisotropic conductive sheet 1 includes only a single insulating layer 2 and a plurality of anisotropic conductive portions 3.

The insulating layer 2 has a sheet shape extending in the plane direction. The insulating layer 2 has an insulating first surface 21 which is one surface in the thickness direction, and an insulating second surface 22 which is the other surface in the thickness direction facing the first surface 21 in the thickness direction and the other side in the thickness direction.

The first insulating surface 21 forms one surface of the anisotropic conductive sheet 1 in the thickness direction.

The insulating second surface 22 forms the other surface of the anisotropic conductive sheet 1 in the thickness direction.

Further, a plurality of through holes 6 are formed in the insulating layer 2.

The plurality of through holes 6 are provided corresponding to the plurality of anisotropic conductive portions 3. That is, the plurality of through holes 6 are formed in a one-to-one correspondence with the plurality of anisotropic conductive portions 3. Each of the plurality of through holes 6 penetrates in the thickness direction of the insulating layer 2. The through hole 6 includes a first opening 60 and a second opening 70.

The first opening 60 is divided into a portion (region) on the other side in the thickness direction of the through hole 6. The first opening 60 has a shape corresponding to the first conductor portion 4 described later. Specifically, the first opening 60 has a substantially rectangular shape in cross section. The first opening 60 has a shape recessed from the insulating second surface 22 toward one side in the thickness direction. Specifically, the first opening 60 is partitioned by the first peripheral side surface 61 and the first one side surface 62 of the insulating layer 2.

The first peripheral side surface 61 partitions the outer surface in the surface direction of the first opening 60. The first peripheral side surface 61 has a substantially cylindrical shape (specifically, a cylindrical shape) extending from the insulating second surface 22 to one side in the thickness direction.

The first one surface 62 partitions one surface of the first opening 60 in the thickness direction. The first one surface 62 extends inward in the surface direction from one end edge in the thickness direction of the first peripheral side surface 61. The first one-sided surface 62 has a substantially ring-shaped bottom view. In the inner portion of the first one surface 62, the first opening 60 communicates with the second opening 70. The first one side surface 62 is orthogonal to the first peripheral side surface 61.

The second opening 70 communicates with the first opening 60, and is partitioned into a portion (region) on one side in the thickness direction of the through hole 6. That is, the second opening 70 is located on one side of the first opening 60 in the thickness direction. The second opening 70 partially includes a shape corresponding to the second conductor portion 5, which will be described later. The second opening 70 is partitioned by the second peripheral side surface 8, the extending surface 7, and the facing surface 37 of the insulating layer 2.

The second peripheral side surface 8 has a shape extending in the thickness direction. The second peripheral side surface 8 is arranged inside, for example, the first peripheral side surface 61 when projected in the thickness direction, and is included in the first one side surface 62. The second peripheral side surface 8 is divided into a plurality of (specifically, three) when projected in the thickness direction. The plurality of second peripheral side surfaces 8 are continuous when projected in the plane direction, and are located at intervals from each other when projected in the thickness direction, for example.

Specifically, the second peripheral side surface 8 includes a third peripheral side surface 43, a fourth peripheral side surface 44, and a fifth peripheral side surface 45 as an example of the other peripheral side surface. The second peripheral side surface 8 preferably includes only the third peripheral side surface 43, the fourth peripheral side surface 44, and the fifth peripheral side surface 45. The third peripheral side surface 43 partitions the other side portion of the second opening 70 in the thickness direction.

The third peripheral side surface 43 is located at the other end of the second peripheral side surface 8 in the thickness direction. The third peripheral side surface 43 has a shape extending from the inner end edge of the first one surface 62 to one side in the thickness direction. The third peripheral side surface 43 includes a tapered surface 9. The third peripheral side surface 43 preferably includes only the tapered surface 9.

The tapered surface 9 has, for example, a substantially truncated cone shape (specifically, a truncated cone shape) in which the cross-sectional area (normal cross-sectional area) along the surface direction gradually increases from the inner end edge of the first one surface 62 toward one side in the thickness direction. It has a substantially truncated cone shape). That is, the tapered surface 9 is an inclined surface in which the facing distances facing each other in the surface direction gradually increase toward one side in the thickness direction in a cross-sectional view along the thickness direction.

The angle α formed by the tapered surface 9 and the first one surface 62 is, for example, an acute angle, preferably 75 degrees or less, more preferably 60 degrees or less, and for example, 15 degrees or more, preferably 15 degrees or more. , 30 degrees or more.

The fourth peripheral side surface 44 is located at an intermediate portion in the thickness direction on the second peripheral side surface 8. The fourth peripheral side surface 44 is arranged outside the third peripheral side surface 43 when projected in the thickness direction, and more specifically, the outer edge (specifically, the taper) of the third peripheral side surface 43. It is arranged at a distance on the outside in the surface direction with respect to the one end edge in the thickness direction of the surface 9. The fourth peripheral side surface 44 has a substantially cylindrical shape (specifically, a cylindrical shape) extending in the thickness direction. The fourth peripheral side surface 44 is inclined with respect to the tapered surface 9. Further, the fourth peripheral side surface 44 is parallel to the first peripheral side surface 61 and orthogonal to the first one side surface 62 in a cross-sectional view.

The fifth peripheral side surface 45 is located at one end in the thickness direction on the second peripheral side surface 8. The fifth peripheral side surface 45 is arranged between the third peripheral side surface 43 and the fourth peripheral side surface 44 when projected in the thickness direction, and specifically, the third peripheral side surface 43 and the fourth peripheral side surface 44. More specifically, it is located between the outer edge of the third peripheral side surface 43 (specifically, one edge in the thickness direction of the tapered surface 9) and the fourth peripheral side surface 44. To do. The fifth peripheral side surface 45 has a substantially cylindrical shape (specifically, a cylindrical shape) extending in the thickness direction. The fifth peripheral side surface 45 is parallel to the fourth peripheral side surface 44 in a cross-sectional view.

The extending surface 7 is a connecting surface that connects the third peripheral side surface 43 and the fourth peripheral side surface 44 in the surface direction. Specifically, the extending surface 7 extends outward in the surface direction from one end edge in the thickness direction of the third peripheral side surface 43 (specifically, the outer edge in the surface direction of the tapered surface 9), and is formed on the fourth peripheral side surface 44. It has a shape that reaches the other end edge in the thickness direction. The extending surface 7 is a flat surface. The extending surface 7 has a substantially ring shape in a plan view. The extending surface 7 is included in, for example, the first one surface 62 when projected in the thickness direction. In cross-sectional view, the extending surface 7 is inclined to the tapered surface 9, is orthogonal to the first peripheral side surface 61 and the fourth peripheral side surface 44, and is parallel to the first one side surface 62.

The facing surfaces 37 are arranged to face each other on one side of the extending surface 7 in the thickness direction at intervals. The facing surface 37 connects the fourth peripheral side surface 44 and the fifth peripheral side surface 45. Specifically, the one end edge in the thickness direction of the fourth peripheral side surface 44 and the other end edge in the thickness direction of the fifth peripheral side surface 45 are connected. connect. The facing surface 37 has a substantially ring-shaped bottom view. In cross-sectional view, the facing surface 37 is parallel to the first one surface 62 and the extending surface 7, is orthogonal to the first peripheral side surface 61, the fourth peripheral side surface 44, and the fifth peripheral side surface 45, and is inclined to the tapered surface 9.

The insulating layer 2 has a sandwiched portion 40 partitioned by a first one surface 62, a third peripheral side surface 43, and an extending surface 7. The sandwiched portion 40 includes a substantially trapezoidal shape in cross-sectional view, and has a substantially ring shape. The sandwiched portion 40 includes a pointed portion 46 having a substantially acute-angled triangular shape in cross-sectional view at its inner end. The sharpened portion 46 is a region facing the tapered surface 9, and when projected in the thickness direction, it overlaps with the first one surface 62, but is displaced inward from the extending surface 7.

Examples of the material of the insulating layer 2 include a resin such as polyimide.

The dimensions of the insulating layer 2 are appropriately set according to the application and use thereof. The thickness of the insulating layer 2 is, for example, 5 μm or more, for example, 100 μm or less.

The maximum length L1 in the surface direction of the first opening 60 is the maximum distance between the first peripheral side surfaces 61 facing the surface direction in a cross-sectional view, and is, for example, 1 μm or more, preferably 10 μm or more, more preferably. It is 20 μm or more, more preferably 30 μm or more, and for example, 1,000 μm or less. The opening cross-sectional area of the first opening 60 is, for example, 50 [mu] m ² or more, preferably, 300 [mu] m ² or more, more preferably at 700 .mu.m ² or more, and is, for example, it is 800,000Myuemu ² or less.

The depth (length in the thickness direction) T of the first opening 60 is the length in the thickness direction of the first peripheral side surface 61, and is, for example, 1 μm or more, preferably 2 μm or more, more preferably 3 μm or more. Further, for example, it is 25 μm or less, preferably 18 μm or less. The ratio of the depth of the first opening 60 to the thickness of the insulating layer 2 is, for example, 0.1 or more, preferably 0.2 or more, and for example, 0.9 or less, preferably 0.8. It is as follows.

The thickness direction length (corresponding to the thickness direction length of the tapered surface 9) L2 of the third peripheral side surface 43 is, for example, 2 μm or more, preferably 5 μm or more, and for example, 45 μm or less, preferably 25 μm or less. Is. The surface direction length (corresponding to the surface direction length of the tapered surface 9) L3 of the third peripheral side surface 43 is, for example, 2 μm or more, preferably 5 μm or more, preferably 10 μm or more, and for example, 45 μm or less. , Preferably 25 μm or less.

The length of the fourth peripheral side surface 44 in the thickness direction is the same as the thickness of the second conductor portion 5, which will be described later.

The length of the fifth peripheral side surface 45 in the thickness direction is, for example, 2 μm or more, preferably 5 μm or more, and for example, 45 μm or less, preferably 25 μm or less.

The surface direction length (extension length) L4 of the extension surface 7 is, for example, 3 μm or more, preferably 7 μm or more, more preferably 15 μm or more, still more preferably 30 μm or more, and for example, 1, It is 000 μm or less, preferably 500 μm or less.

The depth (thickness direction length) of the second opening 70 is the total of the thickness direction lengths of the plurality of second peripheral side surfaces 8, that is, the thickness direction length of the third peripheral side surface 43 and the fourth peripheral side surface. It is the total of the thickness direction length of 44 and the thickness direction length of the fifth peripheral side surface 45. The depth (length in the thickness direction) of the second opening 70 is, for example, 3 μm or more, for example, 100 μm or less. The ratio of the depth of the second opening 70 to the thickness of the insulating layer 2 is, for example, 0.1 or more, preferably 0.2 or more, and for example, 0.9 or less, preferably 0.8. It is as follows.

When the dimensions of the insulating layer 2 are within the above range, the anisotropic conductivity of the anisotropic conductive portion is improved.

Each of the plurality of anisotropic conductive portions 3 is arranged in each of the plurality of through holes 6. The anisotropic conductive portion 3 is filled in the first opening 60 and a part of the second opening 70, and has a shape corresponding to them.

The anisotropic conductive portion 3 includes a first conductor portion 4 arranged in the first opening 60 and a second conductor portion 5 arranged in the second opening 70. Preferably, the anisotropic conductive portion 3 includes only the first conductor portion 4 and the second conductor portion 5.

The first conductor portion 4 is filled in the entire first opening 60. As a result, the first conductor portion 4 has the same shape as the first opening portion 60. Specifically, the first conductor portion 4 has a substantially flat plate shape extending in the plane direction. The first conductor portion 4 includes a first surface 31 which is one surface in the thickness direction, a second surface 32 which is the other surface facing the first surface 31 and the other side in the thickness direction, and a peripheral edge of the first surface 31. It integrally has a third surface 33 that connects the peripheral edges of the second surface 32.

The first surface 31 is a flat surface along the surface direction. The first surface 31 is divided into a peripheral end portion 12 and an inner portion 11 located inside the peripheral end portion 12.

The peripheral end portion 12 faces the first one surface 62 of the insulating layer 2. Specifically, the peripheral end portion 12 is a region of the first surface 31 that comes into contact with the first one surface 62. The peripheral end portion 12 has the same shape as the first one surface 62 in a plan view.

The inner portion 11 is a region located inside the peripheral end portion 12 on the first surface 31. The inner portion 11 comes into contact with the second conductor portion 5, which will be described later.

The second surface 32 is a flat surface parallel to the first surface 31. The second surface 32 is exposed from the insulating layer 2. The second surface 32 is an example of the other surface in the thickness direction exposed on the other side in the thickness direction in the anisotropic conductive portion 3. Specifically, the second surface 32 is exposed from the insulating second surface 22 of the insulating layer 2 toward the other side in the thickness direction. Further, the second surface 32 is flush with the insulating second surface 22. The outer edge of the second surface 32 is continuous with the inner edge of the insulating second surface 22.

The third surface 33 is a side surface (peripheral side surface) of the first conductor portion 4. The third surface 33 comes into contact with the first peripheral side surface 61. The third surface 33 extends along the thickness direction and has a straight shape in a cross-sectional view.

In the first conductor portion 4, the peripheral end portion 12 of the first surface 31 and the third surface 33 come into contact with the insulating layer 2. The peripheral end portion 12 of the first surface 31 comes into contact with the sandwiched portion 40.

On the other hand, the entire surface of the second surface 32 is exposed from the insulating layer 2.

The second conductor portion 5 is arranged in the second opening 70. Specifically, the second conductor portion 5 fills the other side portion of the second opening 70 in the thickness direction. The second conductor portion 5 has a substantially hat shape that is open toward one side in the thickness direction.

The second conductor portion 5 has a shape extending with substantially the same thickness, and has a fourth surface 34 which is one surface in the thickness direction and a fifth surface which is the other surface which faces the fourth surface 34 and the other side in the thickness direction. 35 and a sixth surface 36 connecting the peripheral edge of the fourth surface 34 and the peripheral edge of the fifth surface 35 are integrally provided.

The fifth surface 35 comes into contact with the inner portion 11 of the first conductor portion 4, the third peripheral side surface 43 of the insulating layer 2, and the extending surface 7. In the fifth surface 35, the portion of the insulating layer 2 that contacts the third peripheral side surface 43 and the extending surface 7 includes the sandwiched portion 40 together with the peripheral end portion 12 of the first surface 31 of the first conductor portion 4 in the thickness direction. Sandwich (form a sandwich structure).

The peripheral end of the fourth surface 34 comes into contact with the facing surface 37 of the insulating layer 2.

On the other hand, the inner portion of the peripheral end portion of the fourth surface 34 is exposed on one side in the thickness direction, and is an example of the one surface in the thickness direction exposed on one side in the thickness direction in the anisotropic conductive portion 3. The fourth surface 34 is separated from the fifth surface 35 by the same distance (distance in the thickness direction) in the surface direction.

The sixth surface 36 comes into contact with the fourth peripheral side surface 44. The sixth surface 36 has a substantially cylindrical shape (specifically, a cylindrical shape) extending along the thickness direction.

As a result, the second conductor portion 5 includes the inner portion 11 of the first surface 31 of the first conductor portion 4, the third peripheral side surface 43, the extending surface 7, the fourth peripheral side surface 44, and the facing surface 37 of the insulating layer 2. Contact.

The material of the anisotropic conductive portion 3 is not particularly limited, and examples thereof include metals such as copper, chromium, nickel, and gold. These can be used alone or in combination. As the material of the first conductor portion 4, copper is preferably mentioned. As the material of the second conductor portion 5, nickel and gold are preferable. Each of the first conductor portion 4 and the second conductor portion 5 may be a laminated body in which a plurality of layers are laminated in the thickness direction.

The dimensions of the anisotropic conductive portion 3 are appropriately set according to the application and use thereof. The thickness of the anisotropic conductive portion 3 is, for example, 5 μm or more, preferably 10 μm, as the sum of the thickness T of the first conductor portion 4 in the inner portion 11 and the thickness of the second conductor portion 5 facing the inner portion 11. The above, and for example, 100 μm or less, preferably 50 μm or less. The distance between the second surface 32 and the fourth surface 23 is, for example, 10 μm or more, preferably 20 μm or more, and for example, 500 μm or less.

The dimensions of the first conductor portion 4 have the same dimensions as the dimensions of the first opening 60. The area of the second surface 32 (bottom area of the first conductor portion 4) is the same as the opening cross section of the first opening 60. The ratio of the thickness T of the first conductor portion 4 to the thickness of the anisotropic conductive portion 3 is, for example, 20% or more, preferably 40% or more, and for example, 90% or less, preferably 70%. It is as follows.

The thickness of the second conductor portion 5 is, for example, 2 μm or more, preferably 3 μm or more, and for example, 25 μm or less, preferably 18 μm or less. The ratio of the thickness of the second conductor portion 5 to the thickness of the anisotropic conductive portion 3 is, for example, 10% or more, preferably 30% or more, and for example, 80% or less, preferably 60% or less. .. The ratio of the thickness of the second conductor portion 5 to the thickness T of the first conductor portion 4 is, for example, 0.1 or more, preferably 0.2 or more, and for example, 5 or less, preferably 2 or less. is there.

When the dimensions of the anisotropic conductive portion 3 are within the above range, the anisotropic conductivity of the anisotropic conductive portion 3 is improved.

Next, a method for manufacturing the anisotropic conductive sheet 1 shown in FIGS. 1 and 2 will be described with reference to FIGS. 3A to 3E.

First, as shown in FIG. 3A, the base sheet 20 is prepared.

The base sheet 20 has a sheet shape extending in the plane direction. The base sheet 20 includes, for example, a metal layer made of a metal such as stainless steel (not shown) and a resin layer made of a resin such as polyimide, which is arranged on one side of the metal layer in the thickness direction.

Next, as shown in FIG. 3B, a plurality of first conductor portions 4 (see FIG. 1) are arranged on one surface of the base sheet 20 in the thickness direction. For example, a plurality of first conductor portions 4 are formed on one surface of the base sheet 20 in the thickness direction at intervals in the surface direction by a patterning method such as an additive method or a subtractive method.

Next, as shown in FIG. 3C, the first insulating layer 23 is arranged so as to expose the inner portions 11 of the plurality of first conductor portions 4 on one surface in the thickness direction of the base sheet 20.

The first insulating layer 23 corresponds to the other side portion of the insulating layer 2 (see FIG. 2) in the thickness direction. The first insulating layer 23 forms the first peripheral side surface 61, the first one side surface 62, the third peripheral side surface 43, and the extending surface 7.

In order to form the first insulating layer 23, for example, a photosensitive resin varnish is coated on one surface of the base sheet 20 with the first surface 31 and the third surface 33 of the plurality of first conductor portions 4. As a result, a plurality of third peripheral side surfaces 43 are formed by exposure and development. As a result, the first insulating layer 23 that exposes the plurality of inner portions 11 is formed.

Next, as shown in FIG. 3D, the second conductor portion 5 is arranged on the third peripheral side surface 43 and the extending surface 7 of the first insulating layer 23 and the inner portion 11 of the first conductor portion 4.

Examples of the method of arranging the plurality of second conductor portions 5 include plating using the above-mentioned metal-containing plating bath, for example, application of the above-mentioned paste composition containing metal particles, and the like. Is plating, more preferably electrolytic plating.

As a result, each of the plurality of second conductor portions 5 is arranged so as to correspond to each of the plurality of first conductor portions 4.

Next, as shown in FIG. 3E, the second insulating layer 24 is brought into contact with the extending surface 7 of the first insulating layer 23 so that the peripheral end portion of the fourth surface 34 of the second conductor portion 5 and the sixth surface 36 are in contact with each other. Place in.

The second insulating layer 24 corresponds to one side portion of the insulating layer 2 (see FIG. 2) in the thickness direction. The second insulating layer 24 forms the fourth peripheral side surface 44, the facing surface 37, and the fifth peripheral side surface 45.

The method of forming the second insulating layer 24 is the same as that of the first insulating layer 23.

The second opening 70 is formed by the first insulating layer 23 and the second insulating layer 24.

As a result, the insulating layer 2 having a plurality of through holes 6 having the first opening 60 and the second opening 70 and having the first insulating layer 23 and the second insulating layer 24 is formed.

The boundary between the first insulating layer 23 and the second insulating layer 24 may be clearly observed as shown in FIG. 3E, and is unclear and not observed as shown in FIG. You may.

As a result, the anisotropic conductive sheet 1 including the insulating layer 2 and the plurality of anisotropic conductive portions 3 is manufactured on one surface in the thickness direction of the base sheet 20.

Then, as shown in FIG. 3F, the base sheet 20 is removed. For example, the metal layer and the resin layer are sequentially removed from the other side in the thickness direction by etching or the like.

As a result, the second surface 32 and the insulating second surface 22 are exposed on the other side in the thickness direction.

As a result, the anisotropic conductive sheet 1 including the insulating layer 2 and the plurality of anisotropic conductive portions 3 is manufactured.

Next, a method of performing a continuity inspection using the anisotropic conductive sheet 1 will be described with reference to FIG. 3E.

First, as shown by the virtual line on FIG. 3F, a plurality of first terminals 41 are arranged on one side in the thickness direction of the anisotropic conductive sheet 1. At the same time, a plurality of second terminals 42 are arranged on the other side of the anisotropic conductive sheet 1 in the thickness direction.

Examples of the plurality of first terminals 41 include terminals to be inspected, specifically, terminals of semiconductor elements, terminals of flexible printed wiring boards, and the like. Examples of the plurality of second terminals 42 include inspection terminals and the like, and specific examples thereof include a tester probe and the like.

Subsequently, as shown by the solid line in FIG. 3F, the tips of the plurality of first terminals 41 and the tips of the plurality of second terminals 42 are attached to the plurality of fourth surfaces 34 of the anisotropic conductive portion 3. It is in contact with each of the inner portions and each of the plurality of second surfaces 32. After that, the semiconductor element provided with the first terminal 41 and the flexible printed wiring board are inspected for continuity based on the drive of the inspection device (specifically, the tester) provided with the second terminal 42.

In this anisotropic conductive sheet 1, since the first conductor portion 4 is formed in a substantially flat plate shape, it is easy to secure a sufficient thickness T, and therefore, the anisotropic conductivity of the anisotropic conductive portion 3 is ensured. Can be improved to.

Further, the peripheral end portion of the first conductor portion 4 and the portion of the second conductor portion 5 that contacts the extending surface 7 sandwich the sandwiched portion 40 of the insulating layer 2 in the thickness direction. Therefore, it is possible to prevent the anisotropic conductive portion 3 from falling off from the insulating layer 2.

Therefore, the anisotropic conductive sheet 1 can achieve both the suppression of the anisotropic conductive portion 3 from falling off from the insulating layer 2 and the excellent anisotropic conductivity of the anisotropic conductive portion 3.

<Modification example>
In the modified example, the same members and processes as in one embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the modified example can exert the same action and effect as that of one embodiment, except for special mention. Further, one embodiment and a modification thereof can be appropriately combined.

As shown in FIG. 4, the second conductor portion 5 may further include a conductor attachment portion 52. That is, the second conductor portion 5 in the modified example of FIG. 4 includes a conductor main body portion 51 and a conductor accessory portion 52.

The conductor body portion 51 in the modified example of FIG. 4 corresponds to the second conductor portion 5 of one embodiment. In this modification, the conductor body 51 corresponds to the other side of the second conductor 5 in the thickness direction.

The conductor auxiliary portion 52 is arranged on one surface of the conductor main body portion 51 in the thickness direction. The conductor auxiliary portion 52 corresponds to one side portion of the second conductor portion 5 in the thickness direction. The conductor auxiliary portion 52 is in contact with the fifth peripheral side surface 45. One surface of the conductor auxiliary portion 52 in the thickness direction corresponds to the fourth surface 34 of the second conductor portion 5. The thickness of the conductor auxiliary portion 52 is, for example, 0.01 μm or more and 1 μm or less.

Further, the anisotropic conductive sheet 1 further includes a third conductor portion 48.

The third conductor portion 48 is in contact with the second surface 32 of the first conductor portion 4 and the insulating second surface 22 of the insulating layer 2 located around (near the outside) of the first conductor portion 4. The third conductor portion 48 includes the first conductor portion 4 when viewed from the bottom surface, and has a dimension (length in the plane direction) slightly larger than that of the first conductor portion 4.

The material and thickness of the third conductor portion 48 are the same as those of the conductor auxiliary portion 52.

In the manufacturing method of one embodiment, the insulating layer 2 is formed from two insulating layers (first insulating layer 23 and second insulating layer 24). For example, as shown in FIGS. 5A to 5G, three insulating layers are formed. The insulating layer 2 can also be formed from the insulating layers (third insulating layer 25, fourth insulating layer 26, and fifth insulating layer 27).

In this modification, as shown in FIG. 5A, the base sheet 20 is first prepared, and then, as shown in FIG. 5B, the third insulating layer 25 is arranged on one surface of the base sheet 20 in the thickness direction. .. The third insulating layer 25 is formed on one surface of the base sheet 20 in the thickness direction in the reverse pattern of the first conductor portion 4. The third insulating layer 25 forms the insulating second surface 22 and the first peripheral side surface 61 of the insulating layer 2 (see FIG. 2).

Next, as shown in FIG. 5C, the first conductor portion 4 is formed on the base sheet 2 on one surface (exposed surface) in the thickness direction exposed from the third insulating layer 25, and then as shown in FIG. 5D. The fourth insulating layer 26 is arranged with respect to the third insulating layer 25 and the first conductor portion 4.

The third insulating layer 25 and the fourth insulating layer 26 correspond to the first insulating layer 23 (see FIG. 3C) in the above-described modification, and specifically have the same shape as the first insulating layer 23. The fourth insulating layer 26 forms the first one surface 62, the third peripheral side surface 43, and the extending surface 7.

Next, as shown in FIG. 5E, the second conductor portion 5 is formed, and subsequently, as shown in FIG. 5F, the fifth insulating layer 27 is formed. The fifth insulating layer 27 corresponds to the second insulating layer 24 (see FIG. 3E) in the above-described modification, and specifically has the same shape as the second insulating layer 24. The fifth insulating layer 27 forms the fourth peripheral side surface 44, the facing surface 37, and the fifth peripheral side surface 45. As a result, the insulating layer 2 composed of the third insulating layer 25, the fourth insulating layer 26, and the fifth insulating layer 27 is formed.

Then, as shown in FIG. 5G, the base sheet 20 is removed.

As shown in FIG. 6, in this modification, the third peripheral side surface 43 includes a tapered surface 9 and a vertical surface 10.

The tapered surface 9 corresponds to the other side portion in the thickness direction on the third peripheral side surface 43.

The vertical surface 10 is arranged on one side of the tapered surface 9 in the thickness direction. That is, the vertical surface 10 corresponds to a portion on one side in the thickness direction of the third peripheral side surface 43. Specifically, the vertical surface 10 extends from one end edge of the tapered surface 9 in the thickness direction to one side in the thickness direction and is continuous with the extending surface 7. The vertical surface 10 has a substantially cylindrical shape extending in the thickness direction (specifically, a substantially cylindrical shape or a substantially square tubular shape that shares an axis with the frustum shape of the tapered surface 9). The vertical surface 10 is a straight surface in a cross-sectional view. Specifically, in the cross-sectional view, the facing distances of the two vertical surfaces 10 facing each other in the surface direction are the same.

On the other hand, as shown in FIG. 7, in this modified example, the second peripheral side surface 43 does not include the tapered surface 9, but includes the vertical surface 10. Specifically, the second peripheral side surface 43 includes only the vertical surface 10.

Further, in one embodiment, the second surface 32 of the first conductor portion 4 is flush with the insulating second surface 22 of the insulating layer 2, but as shown in FIG. 8, the insulating second surface of the insulating layer 2 is provided. It may be located on the other side in the thickness direction from the surface 22.

In this modified example, as shown in FIG. 8, when the other side portion in the thickness direction of the first conductor portion 4 is projected in the plane direction, the first conductor portion 4 is moved from the insulating second surface 22 of the insulating layer 2 to the other side in the thickness direction. It is protruding. Specifically, the third surface 33 of the first conductor portion 4 is covered with the insulating layer 2 on one side in the thickness direction, while the other side in the thickness direction is exposed from the insulating layer 2.

From the modified example shown in FIG. 8, one embodiment shown in FIG. 2 and the modified example shown in FIGS. 6 and 7 are more preferable. In one embodiment shown in FIG. 2, the modified examples shown in FIGS. 6 and 7, since the second surface 32 is flush with the insulating second surface 22, the second surface 32 is one of the thickness directions of the insulating second surface 22. From the modified example shown in FIG. 8 protruding to the side, it is possible to smooth the other surface of the anisotropic conductive sheet 1 in the thickness direction.

As shown in FIG. 9, the second peripheral side surface 43 includes the tapered surface 9 and the vertical surface 10, and the second surface 32 can project from the insulating second surface 22 to one side in the thickness direction.

As shown in FIG. 10, the second peripheral side surface 43 does not include the tapered surface 9, but includes only the vertical surface 10, and the second surface 32 may protrude from the insulating second surface 22 to one side in the thickness direction. it can.

Further, as shown in FIG. 11, the peripheral end portion of the fourth surface 34 of the second conductor portion 5 can be exposed to one side in the thickness direction.

The sixth surface 36 of the second conductor portion 5 is spaced apart from the fourth peripheral side surface 44 of the insulating layer 2.

The second peripheral side surface 8 does not include the fifth peripheral side surface 45, and includes only the third peripheral side surface 43 and the fourth peripheral side surface 44. One end edge of the fourth peripheral side surface 44 in the thickness direction is continuous with the first insulating surface 21.

Further, in each of the modified examples of FIGS. 6 to 11, as shown by the virtual line, the conductor auxiliary portion 52 and / or the third conductor portion 48 may be further provided.

Further, in one embodiment, the first conductor portion 4 may have a size larger than that of the second conductor portion 5 in a plan view, but may have the same dimensions or smaller dimensions, for example, although not shown. Even in this modification, the insulating layer 2 has a sandwiched portion 40.

1 Heteroscopic conductive sheet 2 Insulation layer 3 Heteroscopic conductive part 4 1st conductor part 5 2nd conductor part 6 Opening 7 Extending surface 8 Peripheral side surface 9 Tapered surface 11 Inner part 12 Peripheral end part 22 Insulation 2nd surface 31st 1 surface (1st conductor layer)
32 Second surface (first conductor layer)
43 Second peripheral side surface (an example of peripheral side surface)

Claims (2)

An insulating layer having a through hole penetrating in the thickness direction,
It is provided with an anisotropic conductive portion which is arranged in the through hole and whose one surface and the other surface facing each other in the thickness direction are exposed to each of the one side and the other side in the thickness direction.
The through hole has a first opening defined in the other side portion in the thickness direction and a second opening portion communicating with the first opening portion and partitioned in the one side portion in the thickness direction.
The insulating layer has a peripheral side surface on the other side that partitions the other side portion in the thickness direction of the second opening, and an extending surface extending outward in the surface direction orthogonal to the thickness direction from one end edge in the thickness direction of the peripheral side surface on the other side. Have and
The anisotropic conductive portion includes a first conductor portion arranged in the first opening portion and a second conductor portion arranged in the second opening portion.
The first conductor portion is formed in a substantially flat plate shape extending in the plane direction.
In the first conductor portion
The other surface is exposed to the other side in the thickness direction,
The peripheral end of one surface comes into contact with the insulating layer,
The inner portion located inside the peripheral end portion on one surface comes into contact with the second conductor portion, and
The second conductor portion comes into contact with the other side peripheral side surface and
In the second conductor portion
The other surface is in contact with the inner portion and the extending surface.
An anisotropic conductive sheet, characterized in that one surface is exposed to one side in the thickness direction. The anisotropic conductive sheet according to claim 1, wherein the other surface in the thickness direction of the first conductor portion is flush with the other surface in the thickness direction of the insulating layer.

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