WO2024080349A1

WO2024080349A1 - Anisotropic conductive sheet, electrical inspection device, and electrical inspection method

Info

Publication number: WO2024080349A1
Application number: PCT/JP2023/037132
Authority: WO
Inventors: 克典西浦; 博之山田; 大典山田; 真雄堀
Original assignee: 三井化学株式会社
Priority date: 2022-10-14
Filing date: 2023-10-13
Publication date: 2024-04-18

Abstract

This anisotropic conductive sheet comprises: an insulating layer which has a plurality of through holes; and a plurality of conductive parts which are respectively disposed to inner walls of the plurality of through holes. The insulating layer has a first elastomer layer, a second elastomer layer, an intermediate high-elastic-modulus layer which is disposed therebetween, and at least one first surface-layer high-elastic-modulus layer which disposed on a surface of the first elastomer layer that is on the opposite side from the intermediate high-elastic-modulus layer and which constitutes a first surface. The storage modulus of the at least one first surface-layer high-elastic-modulus layer and intermediate high-elastic-modulus layer at 25°C is higher than the storage modulus of the first elastomer layer and the second elastomer layer at 25°C.

Description

Anisotropic conductive sheet, electrical inspection device, and electrical inspection method

The present invention relates to an anisotropic conductive sheet, an electrical inspection device, and an electrical inspection method.

Semiconductor devices such as printed wiring boards mounted on electronic products are usually subjected to electrical testing. Electrical testing is usually performed by electrically contacting a board having electrodes of an electrical testing device with the terminals of the object to be tested, such as a semiconductor device, and reading the current when a specified voltage is applied between the terminals of the object to be tested. In order to ensure electrical contact between the electrodes of the board of the electrical testing device and the terminals of the object to be tested, an anisotropic conductive sheet is placed between the board of the electrical testing device and the object to be tested.

Anisotropic conductive sheets are sheets that are conductive in the thickness direction and insulating in the surface direction, and are used as probes (contacts) in electrical testing. Such anisotropic conductive sheets are used by applying a pressing load to ensure a reliable electrical connection between the board of the electrical testing device and the object being tested.

Various types of such anisotropic conductive sheets are under consideration. Figures 1A and 1B are schematic diagrams of the anisotropic conductive sheet of Patent Document 1. Patent Document 1 discloses an anisotropic conductive sheet 10 having an insulating layer 11 with a plurality of through holes 12 and a plurality of conductive layers 13 arranged corresponding to each of the plurality of through holes 12 (see Figures 1A and 1B). The insulating layer 11 has an elastomer layer 11A and two heat-

resistant resin layers

11B and 11C laminated on both sides of the elastomer layer 11A (see Figures 1A and 1B).

International Publication No. 2021/100824

When conducting electrical testing, the anisotropic conductive sheet is cut to a specified size and placed on the board of an electrical testing device. However, anisotropic conductive sheets containing multiple layers with significantly different elastic moduli, such as those described above, can sometimes undergo dimensional changes immediately after being cut.

In other words, the anisotropic conductive sheet has a structure in which multiple layers with significantly different elastic moduli are laminated together. As a result, residual stress is likely to occur inside the anisotropic conductive sheet due to the difference in linear thermal expansion coefficients. When such an anisotropic conductive sheet is cut, the internal residual stress is released during cutting, making it prone to dimensional changes. If the dimensional change is large, the distance between the multiple conductive layers will fluctuate, causing poor contact during electrical testing.

The present invention was made in consideration of the above problems, and aims to provide an anisotropic conductive sheet, an electrical inspection device, and an electrical inspection method that can reduce dimensional changes, for example, when cut out.

The above problem can be solved by the following configuration.

[1] An anisotropic conductive sheet including an insulating layer having a first surface on one side in a thickness direction, a second surface on the other side, and a plurality of through holes penetrating from the first surface to the second surface, and a plurality of conductive portions arranged on inner wall surfaces of each of the plurality of through holes, wherein the insulating layer has a first elastomer layer, a second elastomer layer, an intermediate high elastic modulus layer arranged between the first elastomer layer and the second elastomer layer, and at least one first surface high elastic modulus layer arranged on a surface of the first elastomer layer opposite to the intermediate high elastic modulus layer and constituting the first surface, wherein the storage modulus at 25°C of the at least one first surface high elastic modulus layer and the intermediate high elastic modulus layer is higher than the storage modulus at 25°C of the first elastomer layer and the second elastomer layer.
[2] The intermediate high elastic modulus layer contains a resin composition having a glass transition temperature of 150° C. or higher.
The anisotropic conductive sheet according to [1].
[3] The anisotropic conductive sheet according to [1] or [2], further comprising a primer layer disposed between the intermediate high elastic modulus layer and at least one of the first elastomer layer and the second elastomer layer, the primer layer containing a polycondensate of a metal alkoxide.
[4] The anisotropic conductive sheet according to any one of [1] to [3], wherein the at least one first surface high elastic modulus layer is a plurality of first surface high elastic modulus layers, and the plurality of first surface high elastic modulus layers are arranged spaced apart from one another on the first elastomer layer.
[5] The anisotropic conductive sheet according to [4], further comprising a plurality of first conductive layers arranged on the plurality of first surface high elastic modulus layers, respectively, and connected to one or more of the conductive portions.
[6] The anisotropic conductive sheet according to any one of [1] to [5], wherein the intermediate high elastic modulus layer and the at least one first surface high elastic modulus layer have a storage modulus of 1.0×10 ⁸ to 1.0×10 ¹⁰ Pa at 25° C.
[7] The anisotropic conductive sheet according to any one of [1] to [6], wherein the first elastomer layer and the second elastomer layer contain a cross-linked product of a silicone rubber composition.
[8] The anisotropic conductive sheet according to any one of [1] to [7], wherein the insulating layer is disposed on a surface of the second elastomer layer opposite the intermediate high elastic modulus layer and further includes at least one second surface high elastic modulus layer constituting the second surface, and the storage modulus of the at least one second surface high elastic modulus layer at 25°C is higher than the storage moduli of the first elastomer layer and the second elastomer layer at 25°C.
[9] The anisotropic conductive sheet described in [8], wherein the at least one second surface high elasticity layer is a plurality of second surface high elasticity layers, and the plurality of second surface high elasticity layers are arranged spaced apart from each other on the second elastomer layer.
[10] The anisotropic conductive sheet according to [9], further comprising a plurality of second conductive layers arranged on the plurality of second surface high elastic modulus layers, respectively, and connected to one or more of the conductive portions.
[11] An anisotropic conductive sheet used for electrical testing of an object to be tested, the object to be tested being placed on the first surface, the anisotropic conductive sheet according to any one of [1] to [10].

[12] An electrical inspection device comprising: a testing board having a plurality of electrodes; and an anisotropic conductive sheet according to any one of [1] to [11], which is placed on a surface of the testing board on which the plurality of electrodes are arranged.
[13] An electrical inspection method comprising the steps of: laminating a testing board having a plurality of electrodes and an object to be inspected having terminals via the anisotropic conductive sheet described in any one of [1] to [11]; and electrically connecting the electrodes of the testing board and the terminals of the object to be inspected via the anisotropic conductive sheet.

The present invention provides an anisotropic conductive sheet, an electrical inspection device, and an electrical inspection method that can reduce dimensional changes, for example, when cut out.

1A and 1B are schematic diagrams of the anisotropic conductive sheet of Patent Document 1. FIG. 2A is a schematic partially enlarged plan view of the anisotropic conductive sheet according to the present embodiment, and FIG. 2B is a schematic partially enlarged cross-sectional view taken along line 2B-2B in FIG. 2A. 3A and 3B are schematic enlarged plan views showing modified examples of the first conductive layer. 4A to 4F are schematic enlarged partial cross-sectional views showing a method for producing an anisotropic conductive sheet according to the present embodiment. 5A to 5H are schematic enlarged partial cross-sectional views showing a method for producing an anisotropic conductive sheet according to the present embodiment. 6A and 6B are schematic enlarged partial cross-sectional views showing a method for producing an anisotropic conductive sheet according to the present embodiment. FIG. 7A is a schematic plan view of an anisotropic conductive sheet cut out in this embodiment and fixed to a frame, and FIG. 7B is a schematic cross-sectional view of the framed anisotropic conductive sheet of FIG. 7A taken along line 7B-7B. FIG. 8 is a schematic cross-sectional view of an electrical inspection device according to this embodiment. FIG. 9 is a graph showing offset values of dimensions of the sheets after cutting out in Example 1 and Comparative Example 1.

1. Anisotropic conductive sheet Fig. 2A is a schematic partially enlarged plan view of an anisotropic conductive sheet 100, and Fig. 2B is a schematic partially enlarged cross-sectional view of the anisotropic conductive sheet 100 taken along line 2B-2B in Fig. 2A. Figs. 3A and 3B are schematic enlarged plan views showing modified examples of the first conductive layer 122A.

As shown in Figures 2A and 2B, the anisotropic conductive sheet 100 has an insulating layer 110, a plurality of conductive layers 120, and a plurality of conductive fillers 130.

The anisotropic conductive sheet 100 may have one or more regions (electrode regions) in which a plurality of conductive layers 120 and a plurality of conductive fillers 130 are formed in the insulating layer 110. The area surrounding the above region may be a first exposed portion 140a in which the insulating layer 110 is exposed due to the absence of a conductive layer or the like (see FIG. 2A).

1-1. Insulating layer 110
The insulating layer 110 includes a first elastomer layer 111A, a second elastomer layer 111B, an intermediate high elastic modulus layer 112, and at least one first surface high elastic modulus layer 113A.

In this embodiment, the insulating layer 110 includes a first elastomer layer 111A, a second elastomer layer 111B, an intermediate high elastic modulus layer 112, at least one first surface high elastic modulus layer 113A, at least one second surface high elastic modulus layer 113B, and four primer layers 114. The insulating layer 110 has a first surface 110a on one side in the thickness direction, a second surface 110b on the other side, and a plurality of through holes 115 that penetrate from the first surface 110a to the second surface 110b (see FIG. 2B).

(First elastomer layer 111A)
The first elastomer layer 111A is a low elastic modulus layer that is easily elastically deformed when pressure is applied in the thickness direction.

The first elastomer layer 111A is not particularly limited, but examples thereof include a cross-linked product of a rubber composition including silicone rubber, urethane rubber (urethane polymer), acrylic rubber (acrylic polymer), ethylene-propylene-diene copolymer (EPDM), chloroprene rubber, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, polybutadiene rubber, natural rubber, fluorine-based rubber, etc., or a thermoplastic elastomer composition including a polyester-based thermoplastic elastomer, an olefin-based thermoplastic elastomer, etc. Among these, a cross-linked product of a rubber composition is preferred, and a cross-linked product of a silicone rubber composition is more preferred. The silicone rubber may be any of addition type, condensation type, and radical type.

The rubber composition may further contain a crosslinking agent as necessary. The crosslinking agent may be appropriately selected depending on the type of rubber. For example, examples of crosslinking agents for silicone rubber include addition reaction catalysts such as metals, metal compounds, and metal complexes (platinum, platinum compounds, and complexes thereof) that have catalytic activity for hydrosilylation reactions; and organic peroxides such as benzoyl peroxide, bis-2,4-dichlorobenzoyl peroxide, dicumyl peroxide, and di-t-butyl peroxide. Examples of crosslinking agents for acrylic rubber include epoxy compounds, melamine compounds, and isocyanate compounds.

For example, examples of crosslinked rubber compositions containing silicone rubber include an addition crosslinked product of a composition containing an organopolysiloxane having a hydrosilyl group (SiH group), an organopolysiloxane having a vinyl group, and an addition reaction catalyst; an addition crosslinked product of a composition containing an organopolysiloxane having a vinyl group and an addition reaction catalyst; and a crosslinked product of a composition containing an organopolysiloxane having a _SiCH3 group and an organic peroxide curing agent.

The rubber composition may further contain other components such as a silane coupling agent and a filler as necessary.

The storage modulus of first elastomer layer 111A at 25° C. is lower than the storage modulus of intermediate high elastic modulus layer 112 and first outer high elastic modulus layer 113A at 25° C. The storage modulus of the cross-linked product of the rubber composition constituting first elastomer layer 111A at 25° C. is preferably 1.0×10 ⁷ Pa or less, and more preferably 1.0×10 ⁵ to 9.0×10 ⁶ Pa. The storage modulus of the cross-linked product of the rubber composition can be measured in accordance with JIS K 7244-1:1998/ISO6721-1:1994.

The glass transition temperature of the cross-linked product of the rubber composition is not particularly limited, but from the viewpoint of preventing damage to the terminals of the test object, it is preferably -30°C or lower, and more preferably -40°C or lower. The glass transition temperature can be measured in accordance with JIS K 7095:2012.

The storage modulus and glass transition temperature of the crosslinked product of the above rubber composition can be adjusted by adjusting the composition of each composition.

The first elastomer layer 111A may be composed of one layer (see FIG. 2B), or may be composed of multiple layers with different compositions or physical properties. When the first elastomer layer 111A is composed of multiple layers, the storage modulus and glass transition temperature of the first elastomer layer 111A refer to the storage modulus and glass transition temperature of the thickest layer among the multiple layers.

(Second elastomer layer 111B)
The second elastomer layer 111B has the same or similar structure as the first elastomer layer 111A, and detailed description thereof will be omitted. That is, the shape, structure, material, and physical properties of the second elastomer layer 111B may be the same or similar to the shape, structure, material, and physical properties of the first elastomer layer 111A.

The composition of the first elastomer layer 111A and the composition of the second elastomer layer 111B may be different. Furthermore, the thickness of the first elastomer layer 111A and the thickness of the second elastomer layer 111B may be different. From the viewpoint of suppressing warping of the anisotropic conductive sheet 100, it is preferable that they are equal, and the ratio of the thickness of the second elastomer layer 111B to the thickness of the first elastomer layer 111A may be, for example, 0.8 to 1.2.

(Intermediate high elastic modulus layer 112)
The intermediate high elastic modulus layer 112 is a high elastic modulus layer disposed between the first elastomer layer 111A and the second elastomer layer 111B. The storage modulus of the intermediate high elastic modulus layer 112 at 25° C. is higher than the storage modulus of the first elastomer layer 111A and the second elastomer layer 111B at 25° C. The intermediate high elastic modulus layer 112 is one continuous high elastic modulus layer, so that when the sheet is cut out, the residual stress inside the sheet is not excessively released. This can reduce dimensional changes.

As described above, the storage modulus at 25° C. of the resin composition constituting the intermediate high elastic modulus layer 112 only needs to be higher than the storage modulus at 25° C. of the cross-linked product of the rubber composition constituting the first elastomer layer 111A and the second elastomer layer 111B, and is, for example, preferably 1.0×10 ⁸ to 1.0×10 ¹⁰ Pa, and more preferably 1.0×10 ⁸ to 8.0×10 ⁹ Pa. In addition, the ratio (G2/G1) of the storage modulus at 25° C. G2 of the resin composition constituting the intermediate high elastic modulus layer 112 to the storage modulus at 25° C. G1 of the cross-linked product of the rubber composition constituting the first elastomer layer 111A or the second elastomer layer 111B may be, for example, 100 to 100,000.

The linear expansion coefficient of the resin composition is preferably lower than the linear expansion coefficient of the cross-linked product of the rubber composition. Specifically, the linear expansion coefficient of the resin composition is preferably 60 ppm/K or less, and more preferably 50 ppm/K or less.

The glass transition temperature of the resin composition is preferably higher than the glass transition temperature of the cross-linked product of the rubber composition. Specifically, since the electrical testing is performed at approximately -40 to 150°C, the glass transition temperature of the resin composition is preferably 150°C or higher, and more preferably 150 to 500°C. The glass transition temperature can be measured by the same method as described above.

The composition of the resin composition is not particularly limited as long as it has at least a storage modulus that satisfies the above range. The resin contained in the resin composition is preferably a heat-resistant resin whose glass transition temperature satisfies the above range, and examples thereof include engineering plastics such as polyamide, polycarbonate, polyarylate, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, and polyetherimide, as well as acrylic resins, urethane resins, epoxy resins, and olefin resins. The resin composition may further contain other components such as a filler as necessary. The resin composition may be in the form of a film.

The storage modulus, glass transition temperature, and linear expansion coefficient at 25°C of the resin composition constituting the intermediate high elasticity layer 112 may be the same as or different from the storage modulus at 25°C of the resin composition constituting the first surface high elasticity layer 113A. For example, the storage modulus of the resin composition constituting the intermediate high elasticity layer 112 may be higher or lower than the storage modulus of the resin composition constituting the first surface high elasticity layer 113A. In addition, the composition of the resin composition constituting the intermediate high elasticity layer 112 may be the same as or different from the composition of the resin composition constituting the first surface high elasticity layer 113A.

The thickness of the intermediate high elasticity layer 112 may be the same as or different from the thickness of the first surface high elasticity layer 113A. For example, the thickness of the intermediate high elasticity layer 112 may be thicker than the thickness of the first surface high elasticity layer 113A (see FIG. 2B), or may be thinner. The ratio (T2/T1) of the thickness (T2) of the intermediate high elasticity layer 112 to the thickness (T1) of the first elastomer layer 111A is preferably, for example, 0.01 to 0.15, and more preferably 0.05 to 0.1.
The ratio (T2/T) of the thickness (T2) of the intermediate high elastic modulus layer 112 to the thickness (T) of the insulating layer 110 may be 0.005 to 0.1, preferably 0.008 to 0.08. The thickness of the intermediate high elastic modulus layer 112 may be, for example, 5 to 20 μm.

(First Outer High Elasticity Layer 113A)
At least one first surface high elastic modulus layer 113A is disposed on the surface of the first elastomer layer 111A opposite to the intermediate high elastic modulus layer 112. In this embodiment, the at least one first surface high elastic modulus layer 113A is a plurality of first surface high elastic modulus layers 113A. The plurality of first surface high elastic modulus layers 113A are disposed spaced apart from each other on the first elastomer layer 111A. The first surface high elastic modulus layer 113A constitutes the first surface 110a of the insulating layer 110.

The storage modulus of the first surface high elasticity layer 113A at 25°C is higher than the storage modulus of the first elastomer layer 111A and the second elastomer layer 111B at 25°C. Therefore, even when heated during electrical testing, it is possible to suppress thermal fluctuations in the center-to-center distance between the multiple first conductive layers 122A. In this embodiment, the multiple first surface high elasticity layers 113A are completely separated by the first groove portion 116a (see FIG. 2B), but the first surface high elasticity layers 113A do not have to be completely separated and may be one continuous layer.

The storage modulus, glass transition temperature, and linear expansion coefficient at 25°C of the first surface high elasticity layer 113A may be the same as or similar to the storage modulus, glass transition temperature, and linear expansion coefficient at 25°C of the intermediate high elasticity layer 112. In addition, the resin composition constituting the first surface high elasticity layer 113A may be the same as or similar to the resin composition constituting the intermediate high elasticity layer 112.

The thickness of the first high elastic modulus surface layer 113A is not particularly limited, but from the viewpoint of making it easier to ensure the elastic deformation of the insulating layer 110, it is preferable that the thickness is thinner than the thickness of the first elastomer layer 111A (see FIG. 2B). Specifically, the ratio (T3/T1) of the thickness (T3) of the first high elastic modulus surface layer 113A to the thickness (T1) of the first elastomer layer 111A is preferably, for example, 0.01 to 0.2, and more preferably 0.02 to 0.15. If the ratio of the thickness of the first high elastic modulus surface layer 113A is equal to or greater than a certain value, the insulating layer 110 can be given an appropriate stiffness without impairing the elastic deformation of the insulating layer 110. This not only improves the handling properties, but also suppresses the fluctuation of the center-to-center distance of the multiple through holes 115 due to heat.

(Second Outer High Elasticity Layer 113B)
At least one second high elastic modulus layer 113B is disposed on the surface of the second elastomer layer 111B opposite to the intermediate high elastic modulus layer 112. In this embodiment, at least one second high elastic modulus layer 113B is a plurality of second high elastic modulus layers 113B, and the plurality of second high elastic modulus layers 113B are disposed on the second elastomer layer 111B at a distance from each other. The second high elastic modulus layer 113B constitutes the second surface 110b of the insulating layer 110. In this embodiment, the second high elastic modulus layer 113B has the same or similar configuration as the first high elastic modulus layer 113A described above, and detailed description will be omitted. That is, the shape, material, and physical properties of the second high elastic modulus layer 113B may be the same as or similar to the shape, material, and physical properties of the first high elastic modulus layer 113A described above.

The composition of the resin composition constituting the first surface high elasticity layer 113A may be different from the composition of the resin composition constituting the second surface high elasticity layer 113B. The thickness of the first surface high elasticity layer 113A may be different from the thickness of the second surface high elasticity layer 113B, but from the viewpoint of suppressing warping of the anisotropic conductive sheet 100, it is preferable that they are equal, and the ratio of the thickness of the second surface high elasticity layer 113B to the thickness of the first surface high elasticity layer 113A may be, for example, 0.8 to 1.2.

(Primer layer 114)
The primer layer 114 is disposed at least between the intermediate high elastic modulus layer 112 and at least one of the first elastomer layer 111A and the second elastomer layer 111B, and can enhance adhesion therebetween. The primer layer 114 can also be disposed between the first surface high elastic modulus layer 113A and the first elastomer layer 111A, and/or between the second surface high elastic modulus layer 113B and the second elastomer layer 111B. In this embodiment, the primer layer 114 is disposed all between the intermediate high elastic modulus layer 112 and the first elastomer layer 111A, between the intermediate high elastic modulus layer 112 and the second elastomer layer 111B, between the first surface high elastic modulus layer 113A and the first elastomer layer 111A, and between the second surface high elastic modulus layer 113B and the second elastomer layer 111B (see FIG. 2B).

The primer layer 114 contains a polycondensate of a metal alkoxide. A polycondensate of a metal alkoxide exhibits good affinity to both organic compounds such as heat-resistant resins and inorganic compounds such as silicone compounds. Therefore, the primer layer 114 exhibits good affinity to both the intermediate high elastic modulus layer 112, which contains, for example, a heat-resistant resin, and the first elastomer layer 111, which contains, for example, a cross-linked product of a silicone rubber composition, and can enhance the adhesion between these layers.

The primer layer 114 is obtained by polycondensing a metal alkoxide using a sol-gel method in a primer solution containing the metal alkoxide and an organic solvent or water.

The metal alkoxide is represented by the following general formula (1).
Formula (1): R ¹ _n M(OR ² ) _m

In formula (1),
M represents a metal atom. Examples of the metal atom include silicon, zirconium, titanium, aluminum, etc., and is preferably silicon.
^R1 and ^R2 are each an organic group having a carbon number of 1 to 8. Examples of the organic group include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and an i-butyl group.
m represents an integer of 1 or more, n represents an integer of 0 or more, and n+m represents the valence of M.

Examples of metal alkoxides represented by formula (1) include alkoxysilanes such as tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, p-styryltrimethoxysilane, 3-chloropropyltriethoxysilane, trifluoromethyltrimethoxysilane, and trifluoromethyltriethoxysilane, as well as the corresponding alkoxyaluminum, alkoxyzirconium, and alkoxytitanium.

The content of the metal alkoxide can be 50% by mass or more, preferably 70 to 100% by mass, based on the non-volatile components of the primer solution.

The organic solvent may be any solvent capable of dispersing or dissolving the above components, and is not particularly limited. Examples of the organic solvent include xylene, toluene, benzene, heptane, hexane, trichloroethylene, perchloroethylene, methylene chloride, ethyl acetate, methyl isobutyl ketone, methyl ethyl ketone, ethanol, isopropanol, butanol, cyclohexanone, diethyl ether, rubber volatile oil, silicone solvents, and other organic solvents. The curing accelerator may be an addition reaction catalyst (such as a platinum group metal catalyst) similar to those described above.

The solution may further contain other components as necessary, such as a sol-gel catalyst, a silane coupling agent, and a water-soluble resin.
Examples of sol-gel catalysts include acids and amine-based compounds.
As the silane coupling agent, a known organoalkoxysilane containing an organic reactive group can be used, and examples thereof include silane coupling agents having a vinyl group, silane coupling agents having an amino group (aminopropyltrimethoxysilane, etc.), silane coupling agents having an epoxy group (glycidoxypropyltrimethoxysilane, etc.), and silane coupling agents having a mercapto group (mercaptopropyltrimethoxysilane, etc.).
The water-soluble resin includes polyvinyl alcohol and ethylene-vinyl alcohol copolymer.

The thickness of the primer layer 114 is not particularly limited, but is, for example, 0.01 to 5 μm, and preferably 0.05 to 3 μm. Whether or not the primer layer 114 is present can be confirmed, for example, by observing the cross section using an electron microscope.

The compositions and physical properties of the four primer layers 114 may be the same as each other or may be different. For example, the thicknesses of the four primer layers 114 may be the same as each other or may be different.

(Through hole 115)
The multiple through holes 115 are holes that penetrate from the first surface 110a to the second surface 110b of the insulating layer 110 (see FIG. 2B).

The axial direction of the through hole 115 may be approximately parallel to the thickness direction of the insulating layer 110, or may be inclined. Approximately parallel means that the angle with respect to the thickness direction of the insulating layer 110 is 10° or less. Inclined means that the angle with respect to the thickness direction of the insulating layer 110 is more than 10° and 50° or less, preferably 20 to 45°. In this embodiment, the axial direction of the through hole 115 is approximately parallel to the thickness direction of the insulating layer 110 (see Figure 2B). The axial direction refers to the direction of a line connecting the centers of gravity of the opening of the through hole 115 on the first surface 110a side and the opening on the second surface 110b side.

The shape of the opening of the through-hole 115 on the first surface 110a is not particularly limited and may be, for example, a circle, a rectangle, or any other polygon. In this embodiment, the shape of the opening of the through-hole 115 on the first surface 110a is a circle (see FIG. 2A). Furthermore, the shape of the opening of the through-hole 115 on the first surface 110a side and the shape of the opening on the second surface 110b side may be the same or different, and from the viewpoint of connection stability to the electronic device to be measured, it is preferable that they are the same.

The circle-equivalent diameter D of the opening of the through hole 115 on the first surface 110a side is not particularly limited, and is preferably 1 to 330 μm, more preferably 2 to 200 μm, and even more preferably 10 to 100 μm (see FIG. 2B). The circle-equivalent diameter D of the opening of the through hole 115 on the first surface 110a side refers to the circle-equivalent diameter (diameter of a perfect circle equivalent to the area of the opening) of the through hole 115 when viewed along the axial direction of the through hole 115 from the first surface 110a side. The circle-equivalent diameter D of the opening of the through hole 115 on the first surface 110a side and the circle-equivalent diameter D of the opening of the through hole 115 on the second surface 110b side may be the same or different.

The center-to-center distance (pitch) p of the openings of the multiple through holes 115 on the first surface 110a side is not particularly limited and can be set appropriately in accordance with the pitch of the terminals of the test object (see FIG. 2B). Since the pitch of the terminals of the HBM (High Bandwidth Memory) as the test object is 55 μm and the pitch of the terminals of the PoP (Package on Package) is 400 to 650 μm, the center-to-center distance p of the openings of the multiple through holes 115 can be, for example, 5 to 650 μm. In particular, from the viewpoint of making it alignment-free, it is more preferable that the center-to-center distance p of the openings of the multiple through holes 115 on the first surface 110a side is 5 to 55 μm. The center-to-center distance p of the openings of the multiple through holes 115 on the first surface 110a side refers to the minimum value of the center-to-center distance of the openings of the multiple through holes 115 on the first surface 110a side. The center of the opening of the through hole 115 is the center of gravity of the opening. The center-to-center distance between the openings of the multiple through holes 115 on the first surface 110a side and the center-to-center distance between the openings of the multiple through holes 115 on the second surface 110b side may be the same or different.

The ratio T/D of the axial length of the through hole 115 (thickness T of the insulating layer 110) to the circular equivalent diameter D of the opening of the through hole 115 on the first surface 110a side is not particularly limited, but is preferably 3 to 40 (see FIG. 2B).

(Common subject matter)
The thickness (T) of the insulating layer 110 is not particularly limited as long as it is sufficient to ensure insulation in the non-conductive portions, and may be, for example, 40 to 700 μm, and preferably 100 to 400 μm.

1-2. Conductive layer 120
The conductive layer 120 is disposed corresponding to one or more through holes 115. The conductive layer 120 includes one or more conductive portions 121, a first conductive layer 122A, and a second conductive layer 122B (see FIG. 2B).

The conductive portion 121 is disposed on the inner wall surface of the through hole 115.

The first conductive layer 122A is disposed on the first surface 110a, i.e., on the first outer high elastic modulus layer 113A, and is connected to one or more conductive portions 121. The multiple first conductive layers 122A are disposed spaced apart from one another via the first groove portions 116a.
The second conductive layer 122B is disposed on the second surface 110b, i.e., on the second outer high elastic modulus layer 113B, and is connected to one or more conductive portions 121. The multiple second conductive layers 122B are disposed spaced apart from one another via the second groove portions 116b.

In a plan view of the insulating layer 110, the shapes of the first conductive layer 122A and the second conductive layer 122B are not particularly limited and may be any of rectangular, triangular, other polygonal, circular, etc. In this embodiment, the shapes of the first conductive layer 122A and the second conductive layer 122B are both rectangular (see FIG. 2A). In this embodiment, the shapes and sizes of the multiple first conductive layers 122A are all the same, and the shapes and sizes of the multiple second conductive layers 122B are all the same. In this embodiment, one first conductive layer 122A is arranged for each through hole 115, but this is not limited thereto, and one first conductive layer 122A may be arranged for two or more through holes 115 (see FIGS. 3A and 3B).

The volume resistivity of the material constituting the conductive layer 120 is not particularly limited as long as sufficient conductivity is obtained, but for example, it is preferably 1.0×10 ⁻⁴ Ω·m or less, and more preferably 1.0×10 ⁻⁵ to 1.0×10 ⁻⁹ Ω·m. The volume resistivity can be measured by the method described in ASTM D 991.

The material constituting the conductive layer 120 may have a volume resistivity that satisfies the above range. Examples of materials constituting the conductive layer 120 include metal materials such as copper, gold, platinum, silver, nickel, tin, iron, or an alloy of one of these metals, and carbon materials such as carbon black. In particular, from the viewpoint of having high conductivity and flexibility, the conductive layer 120 preferably contains one or more selected from the group consisting of gold, silver, and copper as a main component. "Containing as a main component" means, for example, that the conductive layer 120 contains 70% by mass or more, preferably 80% by mass or more.

The materials constituting the conductive portion 121, the first conductive layer 122A, and the second conductive layer 122B may be the same or different, but it is preferable that they are the same from the viewpoint of ease of manufacture and easy stability of electrical continuity.

The thickness of the conductive layer 120 may be in a range that is sufficient to provide electrical continuity and does not block the through-holes 115, and may be, for example, 0.1 to 5 μm. The thickness of the conductive portion 121 of the conductive layer 120 is in a direction perpendicular to the thickness direction of the insulating layer 110, and the thicknesses of the first conductive layer 122A and the second conductive layer 122B are in a direction parallel to the thickness direction of the insulating layer 110 (see FIG. 2B).

The first groove portion 116a arranged between the multiple first conductive layers 122A is a recessed strip arranged on the first surface 110a.

The cross-sectional shape of the first groove portion 116a in a direction perpendicular to the extension direction is not particularly limited, and may be rectangular, semicircular, U-shaped, or V-shaped. In this embodiment, the cross-sectional shape of the first groove portion 116a is rectangular.

The width w and depth d of the first groove 116a are preferably set to a range in which the first conductive layer 122A on one side does not come into contact with the first conductive layer 122A on the other side via the first groove 116a when a pressing load is applied (see FIG. 2B).

The width w of the first groove portion 116a is the maximum width on the first surface 110a in a direction perpendicular to the direction in which the first groove portion 116a extends (see FIG. 2B).

The depth d of the first groove 116a is not particularly limited, but is preferably the same as or greater than the thickness of the first surface high elasticity layer 113A. That is, the deepest part of the first groove 116a can be located on the surface of the first elastomer layer 111A or inside it. The depth d of the first groove 116a refers to the depth from the surface to the deepest part of the first conductive layer 122A in the thickness direction of the insulating layer 110 (see FIG. 2B). By dividing the first groove 116a into multiple first surface high elasticity layers 113A, it is possible to prevent the surrounding conductive layer 120 from being pressed in when the test object 520 is placed on it and pressed in.

The second grooves 116b arranged between the multiple second conductive layers 122B on the second surface 110b may be the same as or similar to the first grooves 116a arranged between the multiple first conductive layers 122A on the first surface 110a.

1-3. Conductive filler 130
The conductive filler 130 is filled inside the through hole 115, specifically, inside the cavity 115' of the through hole 115 surrounded by the conductive portion 121. This improves the conductivity of the anisotropic conductive sheet 100. This can increase the resistance while suppressing peeling of the conductive portion 121.

The conductive filler 130 includes a cross-linked conductive rubber composition that includes conductive particles and a rubber component.

The material constituting the conductive particles is not particularly limited, but from the viewpoint of excellent conductivity and flexibility, particles containing one or more selected from the group consisting of gold, silver, and copper are preferred.

The type of rubber component is not particularly limited, and may be the same as the rubber component constituting the first elastomer layer 111A and the second elastomer layer 111B (hereinafter, these are also collectively referred to as "elastomer layer 111"). The type of rubber component constituting the conductive filler 130 may be the same as the type of rubber component constituting the elastomer layer 111, or may be different. From the viewpoint of flexibility, etc., silicone rubber is preferable.

The rubber component content is preferably 5 to 50% by mass based on the total amount of the conductive particles and rubber component. If the rubber component content is 5% by mass or more, it is easy to increase the adhesion of the conductive part 121 to the inner wall surface of the through hole 115, and since the cross-linked product of the conductive rubber composition has sufficient flexibility, it is easy to suppress cracking and peeling of the conductive part 121.

The conductive rubber composition may further contain other components such as a cross-linking agent as necessary. There are no particular limitations on the type of cross-linking agent, and the same cross-linking agent as that used in the rubber composition constituting the elastomer layer 111 can be used.

The storage modulus at 25°C of the cross-linked product of the conductive rubber composition that constitutes the conductive filler 130 is not particularly limited, but is usually likely to be higher than the storage modulus at 25°C of the cross-linked product of the rubber composition that constitutes the elastomer layer 111. However, from the viewpoint of suppressing defects caused by the pressure during pressing being concentrated on the conductive filler 130, it is preferable that it is moderately low. Specifically, the storage modulus at 25°C of the cross-linked product of the conductive rubber composition is preferably 0.1 to 30 MPa, and more preferably 0.2 to 20 MPa. The storage modulus can be measured in a compression deformation mode using the same method as above.

The volume resistivity of the crosslinked product of the conductive rubber composition is preferably 10 ⁻² Ω·m or less, and more preferably 1×10 ⁻⁸ to 1×10 ⁻² Ω·m. The volume resistivity can be measured by the same method as above.

1-4. First exposed portion 140a, second exposed portion 140b
As described later, the anisotropic conductive sheet 100 is attached to a frame 200 and set in an electrical inspection device. Therefore, the anisotropic conductive sheet 100 is cut to fit the size of the opening of the frame 200. (Individually divided).

The anisotropic conductive sheet 100 of this embodiment has a first exposed portion 140a on the first surface 110a at the outer edge of an area in which a plurality of conductive layers 120 and a plurality of conductive fillings 130 are formed, in which the first conductive layer 122A is not disposed and the insulating layer 110 is exposed (see Figure 2A).
Similarly, on the second surface 110b, the anisotropic conductive sheet 100 has a second exposed portion 140b (not shown) at the outer edge of the area in which the multiple conductive layers 120 and the multiple conductive fillings 130 are formed, where the second conductive layer 122B is not disposed and the insulating layer 110 is exposed.

Furthermore, by cutting the anisotropic conductive sheet 100 at the first exposed portion 140a and the second exposed portion 140b when cutting out the anisotropic conductive sheet 100, it is possible to prevent cutting chips of the conductive layer 120 from being mixed in as foreign matter into the anisotropic conductive sheet 100 after cutting.

1-5. Function As described above, an anisotropic conductive sheet having a laminated structure of multiple layers with significantly different elastic moduli is prone to residual stress due to the difference in linear thermal expansion coefficient between these layers. In particular, if the first surface high elastic modulus layer 113A and the second surface high elastic modulus layer 113B are divided into multiple first surface high elastic modulus layers 113A and multiple second surface high elastic modulus layers 113B by the first groove portion 116a and the second groove portion 116b, the residual stress inside the sheet is more likely to be released. As a result, when the sheet is cut out, the residual stress inside is more likely to be released, and dimensional changes are more likely to occur.

In contrast, the anisotropic conductive sheet 100 according to the above embodiment has an intermediate high elastic modulus layer 112. Since the intermediate high elastic modulus layer 112 is a single continuous layer with a high elastic modulus, it is possible to prevent the residual stress inside the sheet from being released excessively when the sheet is cut out. This makes it possible to reduce dimensional changes.

2. Method for Manufacturing Anisotropically Conductive Sheet FIGS. 4A to 4F, 5A to 5H, and 6A and 6B are schematic enlarged partial cross-sectional views showing a method for manufacturing the anisotropically conductive sheet 100. FIG.

The anisotropic conductive sheet 100 is
1) A step of obtaining a laminated sheet 150 including at least a first elastomer layer 111A, a second elastomer layer 111B, an intermediate high elastic modulus layer 112, a first surface high elastic modulus layer 113A, and a second surface high elastic modulus layer 113B (see FIG. 4A );
2) forming a plurality of through holes 115 in the laminated sheet 150 (see FIG. 4B );
3) forming one continuous conductive layer 151 in each area of the laminated sheet 150 where the plurality of through holes 115 are formed (see FIG. 4C );
4) a step of filling the insides of the plurality of through holes 115 with a conductive rubber composition L (see FIG. 4D ); and 5) a step of forming a first groove portion 116a and a second groove portion 116b on the first surface 150a and the second surface 150b of the laminated sheet 150 to divide the portion of the conductive layer 151 on the first surface 150a side into a plurality of first conductive layers 122A and the portion on the second surface 150b side into a plurality of second conductive layers 122B (see FIGS. 4E and 4F ).
It can be manufactured through the following steps.

Regarding step 1), first, a laminate sheet 150 is prepared, which includes at least a first elastomer layer 111A, a second elastomer layer 111B, an intermediate high elastic modulus layer 112, and a first surface high elastic modulus layer 113A. The laminate sheet 150 can be manufactured by any method, and can be manufactured, for example, by the following procedure.

(Preparation of intermediate sheet S1)
After forming a primer layer 114 on at least one surface (both surfaces in FIG. 5B) of the intermediate high elastic modulus layer 112, an elastomer layer 111-1 is formed, thereby obtaining an intermediate sheet S1 (see FIGS. 5A to 5C).

The primer layer 114 can be formed by applying a solution containing the above-mentioned metal alkoxide, followed by drying and heating, thereby polycondensing the metal alkoxide by a sol-gel method.
The elastomer layer 111-1 can be formed by applying, drying and heating a rubber composition for obtaining the first elastomer layer 111A and the second elastomer layer 111B. The rubber composition is preferably a silicone rubber composition, and examples thereof include two-liquid additive liquid silicone rubber compositions (KE2061-50-A/B, KE2061-70-A/B, etc., manufactured by Shin-Etsu Silicones Co., Ltd.).

(Preparation of surface sheet S2)
As described above, a primer layer 114 is formed on one side of the first surface high elastic modulus layer 113A (see Figs. 5D and 5E), and then an elastomer layer 111-2 is formed (see Fig. 5F). Next, the elastomer layer 111-2 and an elastomer sheet 111-3 are bonded together to form an elastomer layer 111-4, thereby obtaining a surface sheet S2 (see Figs. 5G and 5H). The bonding can be performed in the same manner as described below.
The material of the primer layer 114 of the surface sheet S2 may be the same as the material of the primer layer 114 of the intermediate sheet S1, and the material of the elastomer layer 111-2 and the elastomer sheet 111-3 of the surface sheet S2 may be the same as the material of the elastomer layer 111-1 of the intermediate sheet S1. The thickness of the elastomer layer 111-1 and the elastomer layer 111-2 is usually smaller than the thickness of the elastomer sheet 111-3, for example, 5 μm or less.

(Joining)
The elastomer layer 111-1 of the intermediate sheet S1 prepared above and the elastomer layers 111-4 of the two surface sheets S2 prepared above are bonded together (see FIGS. 6A and 6B). The bonding can be performed by heating the bonded elastomer layers 111-1 and 111-4 with a hot plate or the like.
At this time, in order to increase the bonding strength, the surfaces of the elastomer layer 111-1 and the elastomer layer 111-4 may be subjected to a surface treatment such as plasma irradiation before bonding. For example, when the elastomer layers 111-1 and 111-4 contain a cured product of a silicone rubber composition, silanol groups (Si-OH) are generated by plasma irradiation. The condensation reaction between these silanol groups allows for good bonding. In this case, the heating temperature may be any temperature that allows bonding, and may be, for example, a temperature that causes a condensation reaction between silanol groups.

In this embodiment, as described above, the elastomer layer 111-2 (see FIG. 5F), the elastomer sheet 111-3 (see FIG. 5G), and the elastomer layer 111-1 (see FIG. 5C) of the intermediate sheet S1 are joined together to form one first elastomer layer 111A or one second elastomer layer 111B (FIGS. 6A and 6B). Here, the compositions and physical properties of the elastomer layer 111-2 and the elastomer sheet 111-3 of the surface sheet S2, and the elastomer layer 111-1 of the intermediate sheet S1 may be the same or different. For example, the storage modulus of the elastomer layer 111-2 of the surface sheet S2 may be higher than the storage modulus of the elastomer layer 111-1 of the intermediate sheet S1. For the sake of convenience, Figures 5 and 6 show the case where the elastomer layers 111-1, 111-2, and 111-3 have the same composition and physical properties.

In addition, in this embodiment, since the elastomer sheet 111-3 is used, the elastomer layer 111-2 (see FIG. 5F) is formed on the primer layer 114 of the surface sheet S2, and the elastomer layer 111-1 (see FIG. 5C) is formed on the primer layer 114 of the intermediate sheet S1, but these can be omitted. For example, a liquid rubber composition can be applied directly onto the primer layer 114 of the intermediate sheet S1, and then cured to form the elastomer layer 111, which can then be directly bonded to the primer layer 114 of the surface sheet S2. The liquid rubber composition can be, for example, a two-liquid addition curing type silicone rubber composition.

Regarding step 2), a plurality of through holes 115 are then formed in a predetermined region of the laminated sheet 150 (see FIG. 4B). The region in which the plurality of through holes 115 are formed may be one or more. The formation of the through holes 115 can be performed by any method. For example, the formation of the through holes 115 can be performed by a method of mechanically forming holes (e.g., pressing, punching) or a laser processing method. Among them, the formation of the through holes 115 is more preferably performed by a laser processing method, since it is possible to form the through holes 115 that are fine and have high shape accuracy.

The laser can be an excimer laser, a carbon dioxide laser, a YAG laser, or the like, which can drill holes in resin with high precision. Of these, it is preferable to use an excimer laser. There are no particular limitations on the pulse width of the laser, and it may be a microsecond laser, a nanosecond laser, a picosecond laser, or a femtosecond laser. There are also no particular limitations on the wavelength of the laser.

Regarding step 3), next, one continuous conductive layer 151 is formed in each region of the laminated sheet 150 where the plurality of through holes 115 are formed (see FIG. 4C ). Specifically, the conductive layer 151 is formed continuously on the inner wall surfaces of the plurality of through holes 115 of the laminated sheet 150 and on the first surface 150a and the second surface 150b around the openings of the plurality of through holes 115.

The conductive layer 151 can be formed by any method, but is preferably formed by a plating method (e.g., electroless plating or electrolytic plating) since it can be formed thin and with a uniform thickness without blocking the through-hole 115.

Regarding step 4), next, the inside of the plurality of cavities 115' surrounded by the conductive layer 151 is filled with a conductive rubber composition L (see FIG. 4D).

The conductive rubber composition L can be filled, for example, by applying the conductive rubber composition L onto the first surface 150a and then drawing a vacuum inside the cavity 115' from the second surface 150b side. The filled conductive rubber composition L is then crosslinked. If the conductive rubber composition L contains a solvent, it is preferable to further dry it.

Regarding step 5), the first groove 116a and the second groove 116b are formed on the first surface 150a and the second surface 150b of the laminated sheet 150, respectively (see FIGS. 4E and 4F). As a result, the portion of the conductive layer 151 on the first surface 150a side is divided into a plurality of first conductive layers 122A, and the portion of the conductive layer 151 on the second surface 150b side is divided into a plurality of second conductive layers 122B. Furthermore, in this embodiment, the first surface high elasticity layer 113A can be divided into a plurality of first surface high elasticity layers 113A, and the second surface high elasticity layer 113B can be divided into a plurality of second surface high elasticity layers 113B. The formation of the first groove 116a and the second groove 116b can be performed, for example, by a laser processing method. As a result, an anisotropic conductive sheet 100 (original sheet) in which a plurality of through holes 115 and a plurality of conductive layers 120 are formed in the insulating layer 110 can be obtained.

The method for manufacturing the anisotropic conductive sheet 100 may further include other steps in addition to those described above, as necessary. For example, a pretreatment may be performed between steps 2) and 3) to facilitate the formation of the conductive layer 151.

For example, it is preferable to perform a desmear process (pre-processing) on the laminated sheet 150 in which a plurality of through holes 115 are formed, in order to facilitate the formation of the conductive layer 151. The desmear process can be performed by a wet method or a dry method, and either method may be used.

As a wet desmear treatment, in addition to alkali treatment, known wet processes such as the sulfuric acid method, chromate method, and permanganate method can be used.

An example of a dry desmear process is a plasma process. For example, if the laminate sheet 150 is made of a cross-linked silicone rubber composition, plasma processing of the sheet not only enables ashing/etching, but also oxidizes the silicone surface to form a silica film. Forming a silica film can facilitate penetration of the plating solution into the through-hole 115 and can increase adhesion between the conductive portion 121 and the inner wall surface of the through-hole 115. The oxygen plasma process can be performed using, for example, a plasma asher, a high-frequency plasma etching device, or a microwave plasma etching device.

The anisotropic conductive sheet 100 may be cut to a predetermined size and fixed to the frame 200.

3. Framed anisotropic conductive sheet Fig. 7A is a schematic plan view of a framed anisotropic conductive sheet 400, and Fig. 7B is a schematic enlarged cross-sectional view of the framed anisotropic conductive sheet 400 taken along line 7B-7B in Fig. 7A. Note that hatching of the cross section is omitted in Fig. 7B.

As shown in Figures 7A and 7B, the framed anisotropic conductive sheet 400 has an anisotropic conductive sheet 100P, a frame 200, and a sealing material 300.

In this embodiment, the anisotropic conductive sheet 100P protrudes from at least the first surface 200a of the frame 200 when inserted into the opening 210 of the frame 200 (see FIG. 7B). The first surface 200a of the frame 200 and the anisotropic conductive sheet 100P protruding from the first surface 200a are bonded together with a sealing material 300. An object to be inspected is placed on the surface of the anisotropic conductive sheet 100P protruding from the first surface 200a of the frame 200. In this embodiment, the first surface 110a side of the insulating layer 110 has a greater protruding length than the second surface 110b side.

The protrusion length Ha of the anisotropic conductive sheet 100P from the first surface 200a of the frame 200 is not particularly limited, but is, for example, 100 μm or more, and preferably 150 to 400 μm. The protrusion length Hb of the anisotropic conductive sheet 100P from the second surface 200b of the frame 200 is, for example, 30 to 40 μm, but is not particularly limited. This allows for more reliable electrical contact between the anisotropic conductive sheet 100P and the object to be inspected, or between the electrodes of the inspection board and the anisotropic conductive sheet 100P.

The anisotropic conductive sheet 100P is obtained by cutting the above-mentioned anisotropic conductive sheet 100 to the size of the opening 210 of the frame 200. The shape of the anisotropic conductive sheet 100P in a plan view is usually rectangular (including square). The size of the anisotropic conductive sheet 100P in a plan view can be, for example, 1 to 30 mm in the X direction (long side) and 1 to 30 mm in the Y direction (short side).

The frame 200 has an opening 210 and a positioning hole 220 (see FIG. 7B). The material constituting the frame 200 is preferably stronger than the material constituting the elastomer layer 111 of the anisotropic conductive sheet 100P. Such materials include metal, glass, ceramics, heat-resistant resin, etc., and preferably metal such as stainless steel (SUS). When the frame 200 is made of metal, an insulating layer or the like is disposed on the second surface 200b of the frame 200 opposite the first surface 200a.

The thickness of the frame 200 is smaller than the thickness of the anisotropic conductive sheet 100P. This allows the anisotropic conductive sheet 100P to protrude from at least the first surface 200a of the frame 200.

The openings 210 are through holes provided in the frame 200, into which the anisotropic conductive sheet 100P is inserted. The number of openings 210 is not particularly limited, and may be one, or two or more. In this embodiment, the number of openings 210 is two (see FIG. 7A).

The size of the opening 210 only needs to be large enough to allow the anisotropic conductive sheet 100P to be inserted, and is preferably equal to or slightly larger than the size of the anisotropic conductive sheet 100P. That is, there may or may not be a gap between the inner circumferential surface of the opening 210 and the side surface of the anisotropic conductive sheet 100P. Specifically, the gap between the inner circumferential surface of the opening 210 and the side surface of the anisotropic conductive sheet 100P is not particularly limited, but is, for example, 150 μm or less, and preferably 100 μm or less.

It is preferable that the sealing material 300 has affinity with the material constituting the elastomer layer 111 of the anisotropic conductive sheet 100P. Therefore, it is preferable that the sealing material 300 contains a cross-linked product of a rubber composition. The type of rubber component contained in the sealing material 300 can be the same as the rubber component contained in the elastomer layer 111. The type of rubber component contained in the sealing material 300 may be the same as the rubber component contained in the elastomer layer 111, or may be different. Among them, silicone rubber is preferable.

The framed anisotropic conductive sheet 400 can be obtained through the steps of 1) obtaining an anisotropic conductive sheet 100P, 2) inserting the anisotropic conductive sheet 100P into the opening 210 of the frame 200, and 3) forming a sealing material 300 between the first surface 200a of the frame 200 and the anisotropic conductive sheet 100P protruding from the first surface 200a.

Regarding step 1), the anisotropic conductive sheet 100 (original sheet) is cut into a size and shape that fits into the opening 210 of the frame 200 to obtain an anisotropic conductive sheet 100P.

Cutting can be done with a laser or ultrasonic cutter. In this embodiment, the anisotropic conductive sheet 100P can be obtained by cutting the area where the insulating layer 110 is exposed around the area where the multiple conductive layers 120 are formed. This makes it possible to prevent cutting chips of the conductive layer 120 from being mixed in.

Regarding step 2), next, the anisotropic conductive sheet 100P is inserted into the opening 210 of the frame 200, and the sheet is positioned relative to the frame 200.

Regarding step 3), a sealing material 300 is then placed between the first surface 200a of the frame 200 and the anisotropic conductive sheet 100P protruding from the first surface 200a. In this embodiment, the sealing material 300 is placed on the first surface 200a of the frame 200 so as to fill the periphery of the anisotropic conductive sheet 100P. This makes it possible to fix the anisotropic conductive sheet 100P to the frame 200. This makes it possible to obtain a framed anisotropic conductive sheet 400.

4. Electrical Inspection Device and Electrical Inspection Method Fig. 8 is a schematic cross-sectional view of an electrical inspection device 500 according to this embodiment. In this figure, the dimensions in the thickness direction of the main parts are displayed relatively large.

The electrical inspection device 500 is a device that inspects the electrical characteristics (such as continuity) between terminals 521 (between measurement points) of an object to be inspected 520. Note that in the figure, the object to be inspected 520 is also shown in order to explain the electrical inspection method.

As shown in FIG. 8, the electrical testing device 500 has a substrate 510 (test board) having multiple electrodes and a framed anisotropic conductive sheet 400.

The substrate 510 has a number of electrodes 511 on the surface facing the test object 520, which face each measurement point of the test object 520.

The framed anisotropic conductive sheet 400 is placed on the substrate 510 by inserting the positioning pins 512 of the substrate 510 through the positioning holes 220. As a result, the anisotropic conductive sheet 100P is placed on the surface of the substrate 510 on which the electrodes 511 are arranged, and the electrodes 511 of the substrate 510 and the second conductive layer 122B (not shown) of the anisotropic conductive sheet 100P come into contact.

Then, the test object 520 is placed on the anisotropic conductive sheet 100P of the framed anisotropic conductive sheet 400. The test object 520 is not particularly limited, but examples include various semiconductor devices (semiconductor packages) such as HBM and PoP, electronic components, and printed circuit boards. When the test object 520 is a semiconductor package, the measurement point may be a bump (terminal). When the test object 520 is a printed circuit board, the measurement point may be a measurement land or a land for component mounting provided on a conductive pattern. The test object 520 includes, for example, a chip having a total of 264 solder ball electrodes (material: lead-free solder) with a diameter of 0.2 mm and a height of 0.17 mm, arranged at a pitch of 0.3 mm.

Next, we will explain the electrical inspection method using the electrical inspection device 500.

As shown in Figure 8, the electrical inspection method according to this embodiment stacks a substrate 510 having electrodes 511 and an object to be inspected 520 via an anisotropic conductive sheet 100P fixed by a frame 200. This electrically connects the electrodes 511 of the substrate 510 and the terminals 521 of the object to be inspected 520 via the anisotropic conductive sheet 100P.

When carrying out the above process, in order to facilitate sufficient electrical continuity between the electrodes 511 of the substrate 510 and the terminals 521 of the test object 520 via the anisotropic conductive sheet 100P, the test object 520 may be pressed to apply pressure or brought into contact under a heated atmosphere, as necessary.

The anisotropic conductive sheet 100P in the above embodiment has reduced dimensional change when cut out. This reduces the variation in the distance between the multiple conductive layers 120, and prevents poor contact with the object to be inspected.

5. Modifications Although the anisotropic conductive sheet 100 according to the above embodiment has two elastomer layers 111 and one intermediate high elastic modulus layer 112, the present invention is not limited to this and may have three or more elastomer layers 111 and two or more intermediate high elastic modulus layers 112.

In addition, in the anisotropic conductive sheet 100 according to the above embodiment, the primer layer 114 is disposed on all of the intermediate high elasticity layer 112, the first surface high elasticity layer 113A, and the second surface high elasticity layer 113B, but this is not limited thereto, and the primer layer 114 may be omitted depending on the degree of affinity (adhesion) between the intermediate high elasticity layer 112, the first surface high elasticity layer 113A, and the second surface high elasticity layer 113B and the elastomer layer 111.

In addition, in the anisotropic conductive sheet 100 according to the above embodiment, the inside of the through hole 115 is filled with the conductive filler 130, but this is not limited thereto and it does not have to be filled. In addition, the conductive layer 120 has the first conductive layer 122A and the second conductive layer 122B, but this is not limited thereto and it does not have to have the first conductive layer 122A and the second conductive layer 122B.

In addition, the anisotropic conductive sheet 100 according to the above embodiment has a first exposed portion 140a where the insulating layer 110 is exposed around the area (electrode area) where the multiple conductive layers 120 and multiple conductive fillers 130 are formed, but this is not limited thereto, and a conductive layer 151 may be disposed on the insulating layer 110.

The present invention will be explained in detail below with reference to examples, but the present invention is not limited to these.

[Example 1]
(1) Preparation of Laminated Sheet (Preparation of Intermediate Sheet S1)
A solution containing a metal alkoxide (Primer No. 4, manufactured by Shin-Etsu Silicones) was applied to both sides of a polyimide film (thickness 12.5 μm, Kapton 50EN (registered trademark) manufactured by DuPont-Toray Co., Ltd., Tg>300° C., storage modulus at 25° C. 5 GPa) (intermediate high elastic modulus layer 112) and dried to form a primer layer (primer layer 114) having a thickness of 0.7 μm.
Next, a two-liquid additive liquid silicone rubber composition (KE2061-50-A/B manufactured by Shin-Etsu Silicones) was further applied onto the primer layer and cured to form a silicone-based elastomer layer 1 (elastomer layer 111-1) having a thickness of 5 μm.
As a result, an intermediate sheet S1 having a laminated structure of silicone-based elastomer layer 1 (5 μm)/primer layer/polyimide film (12.5 μm)/primer layer/silicone-based elastomer layer 1 (5 μm) was obtained (see FIGS. 5A to 5C).

(Preparation of surface sheet S2)
A primer layer (primer layer 114) having a thickness of 0.7 μm was formed on one side of a polyimide film (thickness 7.5 μm, Kapton 30 (registered trademark), Tg>300° C., storage modulus at 25° C. 5 GPa) (surface high elastic modulus layer 113) in the same manner as described above.
Next, a two-part additive liquid silicone rubber composition (KE2061-70-A/B manufactured by Shin-Etsu Silicones) was further applied onto the primer layer and cured to form a 5 μm-thick silicone-based elastomer layer (elastomer layer 111-2).
This elastomer layer (elastomer layer 111-2, thickness 5 μm) and a commercially available silicone rubber sheet (Sirius manufactured by Fuso Rubber Industries Co., Ltd., thickness 150 μm, storage modulus at 25° C. 1 MPa, elastomer layer 111-3) were each irradiated with plasma. The plasma irradiation was performed under conditions of 800 W, 0.5 L/min, and 1 minute.
Thereafter, the above-mentioned elastomer layer (elastomer layer 111-2, thickness 5 μm) and a commercially available silicone rubber sheet (elastomer layer 111-3, thickness 150 μm) were bonded together at their plasma-irradiated surfaces at normal pressure and heated on a hot plate at 50° C. for 10 minutes to form a silicone-based elastomer layer 2 (elastomer layer 111-4).
As a result, two surface sheets S2 each having a laminated structure of polyimide film (7.5 μm)/primer layer/silicone-based elastomer layer 2 (elastomer layer 111-4, thickness 5 μm+150 μm) were prepared (see FIGS. 5D to 5H).

(Preparation of Laminated Sheet)
The silicone-based elastomer layer 1 (elastomer layer 111-1) of the intermediate sheet S1 and the silicone-based elastomer layer 2 (elastomer layer 111-4) of each of the two surface sheets S2 were irradiated with plasma under the same conditions as above.
Then, the plasma-irradiated silicone-based elastomer layers 2 of the two surface sheets S2 were attached to each of the plasma-irradiated surfaces of the silicone-based elastomer layer 1 of the intermediate sheet S1 at normal pressure (see Figure 6A), and bonded by heating on a hot plate at 50°C for 10 minutes, thereby obtaining a laminated sheet 150 having silicone-based elastomer layers A and B (first elastomer layer 111A and second elastomer layer 111B) (see Figure 6B).

(Measurement of storage modulus and Tg)
The storage modulus of the silicone-based elastomer layers A and B at 25° C. was 1 MPa, and the storage modulus of the polyimide film was 5 GPa at 25° C. The storage modulus was measured in accordance with JIS K 7244-1:1998/ISO6721-1:1994. In addition, when the Tg of the polyimide film was measured in accordance with JIS K 7095:2012, no clear glass transition temperature was observed, but a viscoelastic change was observed at 300° C. or higher, and therefore it was determined to be 300° C. or higher.

(2) Preparation of anisotropic conductive sheet After forming a plurality of through holes 115 (the openings of the plurality of through holes 115 on the first surface 150a side have a circle equivalent diameter of 85 μm) in the stacking direction (thickness direction) of the obtained laminated sheet, a continuous gold (Au) layer was formed by plating on the surface of the laminated sheet (the inner wall surfaces of the through holes 115, the first surface 150a and the second surface 150b).
Next, a conductive elastomer composition, ThreeBond 3303B (containing Ag particles, silicone rubber and a crosslinking agent, with a volume resistivity of the crosslinked product of 3× ¹⁰ Ω·m according to ASTM D 991) manufactured by ThreeBond Co., Ltd., was dropped onto first surface 150a of the obtained sheet, and the composition was introduced and filled into cavity 115′ corresponding to through hole 115 while drawing a vacuum from the second surface 150b side, and the composition was heated at 170° C. to cause crosslinking.
Next, a plurality of first groove portions 116a and second groove portions 116b were formed in a lattice pattern by laser processing on the first surface 150a and the second surface 150b of the obtained sheet, dividing the sheet into a plurality of first surface high elasticity layers 113A and second surface high elasticity layers 113B, and a plurality of first conductive layers 122A and second conductive layers 122B.
As a result, an anisotropic conductive sheet 100 having a laminated structure of polyimide film (7.5 μm)/primer layer/silicone-based elastomer layer A (5 μm+150 μm+5 μm)/primer layer/polyimide film (12.5 μm)/silicone-based elastomer layer B (5 μm+150 μm+5 μm)/primer layer/polyimide film (7.5 μm) was obtained (see FIGS. 2A and 2B). The distance between the centers of gravity of the multiple first conductive layers 122A was 300 μm.

[Comparative Example 1]
(Preparation of surface sheet 1)
A primer layer having a thickness of 0.7 μm was formed on one surface of a polyimide film (thickness 7.5 μm, Kapton 30 (registered trademark), Tg>300° C., storage modulus at 25° C. 5 GPa) in the same manner as above.
Next, a two-liquid additive liquid silicone rubber composition (KE2061-70-A/B manufactured by Shin-Etsu Silicones) was further applied onto the primer layer and cured to form a silicone-based elastomer layer having a thickness of 5 μm.
As a result, a surface sheet 1 having a laminated structure of polyimide film (7.5 μm)/primer layer/silicone-based elastomer layer (5 μm) was obtained.

(Preparation of surface sheet 2)
A surface sheet 2 having a laminated structure of polyimide film/primer layer/silicone-based elastomer layer (5 μm + 300 μm) was prepared in the same manner as the surface sheet S2 of Example 1, except that the commercially available silicone rubber sheet having a thickness of 150 μm was replaced with a commercially available silicone rubber sheet having a thickness of 300 μm (storage modulus at 25° C.: 0.4 GPa).

(Preparation of Laminated Sheet)
The silicone-based elastomer layers of the prepared surface sheets 1 and 2 were irradiated with plasma and then bonded together to obtain a laminated sheet having a laminated structure of polyimide film (7.5 μm)/primer layer/silicone-based elastomer layer (5 μm+300 μm+5 μm)/primer layer/polyimide film (7.5 μm).

(Preparation of anisotropic conductive sheet)
An anisotropic conductive sheet 100 was obtained in the same manner as in Example 1, except that the laminate sheet prepared above was used.

[evaluation]
The obtained anisotropic conductive sheet was cut into a size of 15 mm (X direction) x 5 mm (Y direction) using a femtosecond laser. The dimensions of the sheet immediately after cutting were measured using a digital microscope. The offset value was calculated as the deviation from the reference value. The sheet was cut at 25°C, and the average value of n = 2 was calculated.

The evaluation results are shown in Table 1 and Figure 9. Figure 9 is a graph showing the offset values of the dimensions of the sheets after cutting in Example 1 and Comparative Example 1.

As shown in Table 1, the sheet of Comparative Example 1 had a maximum offset value of -86 μm in the X direction and a maximum offset value of -66 μm in the Y direction, indicating that both dimensions had large changes (see the left side of Figure 9).

In contrast, the sheet of Example 1 has a maximum offset value of -19 μm in the X direction and -15 μm in the Y direction, showing that the dimensional change is reduced in both cases (see the right side of Figure 9).

From these findings, it can be seen that the provision of an intermediate high elastic modulus layer can effectively reduce dimensional change.

This application claims priority from Japanese Patent Application No. 2022-165712, filed on October 14, 2022. The contents of the specification and drawings of that application are incorporated herein by reference in their entirety.

The present invention makes it possible to provide an anisotropic conductive sheet that can reduce dimensional changes, for example, when cut out.

100 Anisotropic conductive sheet 100P (individually cut) anisotropic conductive sheet 110 Insulating layer 110a First surface (of insulating layer) 110b Second surface (of insulating layer) 111A First elastomer layer 111B Second elastomer layer 112 Intermediate high elastic modulus layer 113A First surface high elastic modulus layer 113B Second surface high elastic modulus layer 114 Primer layer 115 Through hole 115' Cavity 116a First groove portion 116b Second groove portion 120 Conductive layer 121 Conductive portion 122A First conductive layer 122B Second conductive layer 130 Conductive filler 140a First exposed portion 140b Second exposed portion 150 Laminated sheet 151 Conductive layer 200 Frame 200a First surface (of frame) 200b Second surface (of frame) 201 Base material layer 202 Frame insulating layer 210 Opening 300 Sealing material 400 Framed anisotropic conductive sheet 500 Electrical inspection device 510 Substrate 511 Electrode 512 Positioning pin 520 Inspection target 521 Terminal

Claims

an insulating layer having a first surface on one side in a thickness direction, a second surface on the other side, and a plurality of through holes penetrating from the first surface to the second surface;
A plurality of conductive portions disposed on inner wall surfaces of the plurality of through holes;
Including,
The insulating layer is
A first elastomeric layer; and
A second elastomeric layer; and
an intermediate high modulus layer disposed between the first elastomeric layer and the second elastomeric layer;
At least one first surface high elastic modulus layer is disposed on a surface of the first elastomer layer opposite to the intermediate high elastic modulus layer and constitutes the first surface;
having
The storage modulus at 25° C. of the at least one first surface high elastic modulus layer and the intermediate high elastic modulus layer is higher than the storage modulus at 25° C. of the first elastomer layer and the second elastomer layer.
Anisotropic conductive sheet.
The intermediate high elastic modulus layer contains a resin composition having a glass transition temperature of 150° C. or higher.
The anisotropic conductive sheet according to claim 1 .
a primer layer disposed between the intermediate high elastic modulus layer and at least one of the first elastomer layer and the second elastomer layer, the primer layer including a polycondensate of a metal alkoxide;
The anisotropic conductive sheet according to claim 1 .
the at least one first surface high elastic modulus layer is a plurality of first surface high elastic modulus layers,
The plurality of first surface high elastic modulus layers are disposed on the first elastomer layer at intervals from each other.
The anisotropic conductive sheet according to claim 1 .
The conductive layer further includes a plurality of first conductive layers disposed on the plurality of first surface high elastic modulus layers, respectively, and connected to one or more of the conductive portions.
The anisotropic conductive sheet according to claim 4 .
the intermediate high elastic modulus layer and the at least one first outer high elastic modulus layer have a storage modulus of 1.0×10 8 to 1.0×10 10 Pa at 25° C.;
The anisotropic conductive sheet according to claim 1 .
the first elastomer layer and the second elastomer layer contain a cross-linked product of a silicone rubber composition;
The anisotropic conductive sheet according to claim 1 .
The insulating layer is
the second elastomer layer is disposed on a surface opposite to the intermediate high elastic modulus layer, and the second surface includes at least one second surface high elastic modulus layer;
The storage modulus of the at least one second surface high elastic modulus layer at 25° C. is higher than the storage modulus of the first elastomer layer and the second elastomer layer at 25° C.
The anisotropic conductive sheet according to claim 1 .
the at least one second surface high elastic modulus layer is a plurality of second surface high elastic modulus layers,
The plurality of second surface high elastic modulus layers are disposed on the second elastomer layer at intervals from each other.
The anisotropic conductive sheet according to claim 8 .
The second conductive layer is disposed on each of the second high elastic modulus layers and connected to one or more of the conductive portions.
The anisotropic conductive sheet according to claim 9 .
An anisotropic conductive sheet used for electrical testing of an object to be tested,
The inspection object is placed on the first surface.
The anisotropic conductive sheet according to claim 1 .
A testing substrate having a plurality of electrodes;
and an anisotropic conductive sheet according to any one of claims 1 to 11, which is disposed on a surface of the testing board on which the plurality of electrodes are disposed.
Electrical testing equipment.
The method includes a step of stacking a testing substrate having a plurality of electrodes and a test object having terminals via the anisotropic conductive sheet according to any one of claims 1 to 11, and electrically connecting the electrodes of the testing substrate and the terminals of the test object via the anisotropic conductive sheet.
Electrical testing methods.