JP2019160784A - Anisotropic conductive sheet and manufacturing method thereof - Google Patents

Abstract

To provide an anisotropic conductive sheet and a manufacturing method thereof that can arrange a conductive layer at high density and is easy to handle.SOLUTION: An anisotropic conductive sheet in which a sheet made of an elastic polymer material is wound, and a plurality of conductive layers made of a thin film containing a conductive material at intervals in the winding direction of the sheet are continuously arranged on at least one surface of the sheet, and the axial direction of winding is the thickness direction, and the ends of the conductive layer are exposed from the front and back surfaces forming both end faces in the thickness direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an anisotropic conductive sheet mainly used for electrical connection and conducting in a thickness direction, and a method for manufacturing the anisotropic conductive sheet. More specifically, the present invention relates to an anisotropic conductive sheet in which the distance between conductive layers arranged on the sheet is extremely small, and a method for manufacturing the anisotropic conductive sheet.

  The anisotropic conductive sheet exhibits conductivity only in the thickness direction. Such an anisotropic conductive sheet is capable of making an electrical connection in a compact manner without using means such as soldering or mechanical fitting, and absorbs physical shocks and strains. There are advantages such as being able to make an electrical connection softly.

  As such an anisotropic conductive sheet, an anisotropic conductive sheet obtained by molding a composition in which a conductive substance is uniformly blended in a polymer substance, or a blended conductive substance in the thickness direction. Anisotropic conductive sheets molded in an oriented state are widely known and are generally used as electrical connection members.

  Examples of use include connectors for electrically connecting electronic components and electric boards in the field of electronic equipment such as personal computers, video players, video cameras, electronic cameras, mobile phones, and game machines, and electric boards and semiconductor devices. A contactor for electrically connecting an electrode to be inspected and an inspection substrate in the field of general inspection is known.

  Among such anisotropically conductive sheets, a conductive layer is formed by orienting a conductive substance in the thickness direction, particularly for electrical connection of electronic parts and electrical boards having a small inter-electrode pitch, and adjacent to each other. An anisotropic conductive sheet that suppresses short circuit between conductive layers has been proposed.

  For example, Patent Document 1 discloses a conductive layer formed in the thickness direction by using conductive particles that are magnetically affected as a conductive substance, and performing magnetic field orientation in the thickness direction by processing with a parallel magnetic field. An anisotropic conductive sheet randomly dispersed in the horizontal direction is disclosed.

  Further, in Patent Document 2, a conductive layer is formed by collecting conductive magnetic particles on convex portions of a magnetic pole plate by applying a parallel magnetic field by providing irregularities on the surface of the magnetic pole plate. A clearly separated anisotropic conductive sheet is disclosed.

JP 51-093393 A Japanese Patent Laid-Open No. 53-147772 JP 2014-044946 A JP 2012-043579 A Japanese Patent Application Laid-Open No. 07-029625 JP 07-31247 A

  However, electronic components and electric substrates, etc., which are found in recent semiconductor devices, etc., have a very small interelectrode pitch (interelectrode pitch is 100 μm or less) and high density multi-electrodes (several hundreds to thousands of full matrix arrangements, etc.) When these anisotropic conductive sheets are used for electrical connection, there are the following problems.

  That is, for example, in the case of the anisotropic conductive sheet disclosed in Patent Document 1, it is necessary to increase the conductive layer in order to cope with the high-density multi-electrode, and the amount of conductive magnetic particles must be increased. Since the horizontal orientation of the conductive magnetic particles is not controlled, if the amount of the conductive magnetic particles is increased, a short circuit occurs between adjacent conductive layers, and desired electrical characteristics cannot be obtained. There is.

  On the other hand, in the case of the anisotropic conductive sheet disclosed in Patent Document 2, in order to cope with a high-density multi-electrode, the convex portions of the magnetic pole plate must be provided with a very high density. If there is a gap between the adjacent conductive layers, insulation between the conductive layer and the insulating portion, which is originally expected, will be insufficient due to the interaction between the magnetic fields derived from the adjacent convex portions, resulting in a short circuit between the adjacent conductive layers. May not be obtained.

In addition, there is a problem that it is very difficult to align all the electrodes of extremely narrow pitches ranging from several hundred to several thousand with the conductive layer of the anisotropic conductive sheet.
On the other hand, as a technique that does not require alignment, for example, Patent Document 3 discloses an anisotropic conductive sheet in which conductive particles are arranged in a full matrix at intervals of several μm.

  In this anisotropic conductive sheet, since conductive particles are arranged in a full matrix at intervals of several μm, the pitch between electrodes which has recently been seen (100 μm or less) and a high density multi-electrode ( Even for hundreds to thousands of full matrix arrangements), it is not necessary to substantially align.

  However, the anisotropic conductive sheet disclosed in Patent Document 3 is premised on adhesion to the electrode to be connected in making an electrical connection. Once the electrical connection is made, the anisotropic conductive sheet is fixed and repeatedly used. Can not. Furthermore, since the conductive layer is composed of one conductive particle, the cushioning property of the seat is poor, and if there is a height variation or a step in the connected electrode, reliable electrical connection is achieved with all the electrodes. Can be difficult.

  Therefore, the contactor has a height variation, and the contactor for electrically connecting the electrode to be inspected and the inspection substrate in the field of electrical inspection such as an electric substrate or a semiconductor device that must be repeatedly connected. Not applicable to

  Patent Document 4 discloses an anisotropic conductive sheet in which a plurality of striped conductive layers are provided on the surface of a sheet made of an elastic polymer substance, and the plurality of sheets are laminated so that the conductive layers intersect perpendicularly. It has been shown that by reducing the width and interval of the striped conductive layer, it is possible to deal with electrodes with an extremely narrow pitch.

  However, in the case of the anisotropic conductive sheet disclosed in Patent Document 4, when the connected electrodes are arranged in a straight line such as a full matrix arrangement, a plurality of conductive layers (electrodes) of the anisotropic conductive sheet are provided on the same conductive layer (electrode). Since the electrodes to be connected are in contact with each other at the same time, if all the electrodes to be connected are simultaneously electrically connected, there is a problem that independent signals cannot be exchanged for each electrode to be connected.

  Furthermore, Patent Document 5 and Patent Document 6 disclose anisotropic conductive sheets in which metal wires are arranged in the thickness direction of a sheet made of an elastic polymer material. In these documents, in consideration of the rigidity of the metal wire, the wire is disposed obliquely to reduce the load at the time of contact.

However, as long as a metal wire is used, the influence of its rigidity is large, and even if it is arranged obliquely, there is still a limit in reducing the load at the time of contact. There is also a circumstance that it is thin, and it is difficult to apply due to the problem of damage to the inspection object.
The objective of this invention is providing the anisotropic conductive sheet which can arrange | position a conductive layer with high density and is easy to handle, and the manufacturing method of this anisotropic conductive sheet.

The anisotropic conductive sheet of the present invention is
An anisotropic structure in which a sheet made of an elastic polymer material is wound, and a plurality of conductive layers made of a thin film containing a conductive material are continuously arranged on at least one surface of the sheet at intervals in the winding direction of the sheet A conductive sheet,
The anisotropic conductive sheet has a thickness direction in the axial direction of winding,
An end portion of the conductive layer is exposed from a front surface and a back surface forming both end surfaces in the thickness direction.

  Thereby, the anisotropic conductive sheet which can arrange | position a conductive layer with high density and is easy to handle can be provided. Further, by exposing the end portion of the conductive layer from the front surface and the back surface, it is possible to reliably energize only by contacting the connected electrode.

The anisotropic conductive sheet of the present invention is
The conductive layer is a thin film having a width of 1 μm to 100 μm and a thickness of 0.1 μm to 30 μm, and is arranged at intervals of 1 μm to 30 μm in the winding direction.

  Thus, by setting the width of the conductive layer to 1 μm to 100 μm and the thickness of the conductive layer to 0.1 μm to 30 μm, the flexibility of the anisotropic conductive sheet is ensured, and the height of the connected electrode is reduced with a low load. Desirable electrical characteristics can be obtained, such as being able to follow variations in height and steps, and reducing the electrical resistance value and contact resistance value of the conductive layer. Furthermore, if the conductive layers are arranged at an interval of 1 μm or more and 30 μm or less, there is no short circuit between adjacent electrodes, and manufacturing is not difficult.

The anisotropic conductive sheet of the present invention is
The sheet has a thickness of 1 μm or more and 100 μm or less.
As a result, winding becomes easy, and the interval between the conductive layers increases in the thickness direction of the wound sheet, and when the electrode pitch of the electrodes to be connected is reduced, all the electrodes cannot be connected together. The problem can be solved.

The anisotropic conductive sheet of the present invention is
The elastic polymer substance is silicone rubber.
Silicone rubber makes it possible to easily obtain a sheet with an arbitrary thickness, and since the curing (solidification) can be controlled in the middle, the sheets wound by reheating after the winding process can be bonded together. The manufacturing process of the anisotropic conductive sheet can be simplified.

The method for producing the anisotropic conductive sheet of the present invention is as follows.
Disposing a plurality of conductive layers made of a thin film containing a conductive material at an interval on at least one surface of a sheet made of an elastic polymer material;
A winding step of winding the sheet in the direction in which the conductive layer is disposed;
And a thin slicing step of creating an anisotropic conductive sheet by cutting the wound sheet in a direction orthogonal to the axial direction of the winding.
By this procedure, an anisotropic conductive sheet can be produced efficiently.

Moreover, the manufacturing method of the anisotropic conductive sheet of the present invention is
After the winding step, the method includes a curing step of immersing the wound sheet in a liquid polymer material and then curing the liquid polymer material.
Thereby, peeling between the wound sheet | seats is suppressed and the anisotropically conductive sheet excellent in durability can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, an anisotropic conductive sheet which can arrange | position a conductive layer with high density and is easy to handle, and the manufacturing method of this anisotropic conductive sheet can be provided.

It is a perspective view which shows the structure of the anisotropically conductive sheet which concerns on embodiment. It is a photograph which shows the anisotropic conductive sheet which concerns on embodiment. It is a perspective view which shows the state which expand | deployed the sheet | seat with which the conductive layer which concerns on embodiment is arrange | positioned. It is a figure explaining the state which the edge part of the conductive layer exposed from the surface and back surface of the thickness direction of the anisotropic conductive sheet which concerns on embodiment. It is a figure which shows the process of producing the anisotropically conductive sheet which concerns on embodiment. It is a figure which shows the process of producing the anisotropically conductive sheet which concerns on embodiment. It is a partial photograph of the anisotropic conductive sheet obtained in Example 1 of an embodiment.

Hereinafter, an anisotropic conductive sheet according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a configuration of an anisotropic conductive sheet according to an embodiment, and FIG. 2 is a photograph taken from the front side. FIG. 3 is a developed view of the sheet constituting the anisotropic conductive sheet.
An anisotropic conductive sheet 2 shown in FIGS. 1 and 2 is formed by winding a sheet 4 made of an elastic polymer material shown in FIG. 3 and slicing it to a predetermined thickness. On the sheet 4, a plurality of conductive layers 6 made of a thin film containing a conductive substance are continuously arranged at intervals in the winding direction. Here, the conductive layer 6 should just be arrange | positioned at the single side | surface or both surfaces of the sheet | seat 4, ie, at least one surface.

  The anisotropic conductive sheet 2 has the axial direction of the sheet 4 wound in the thickness direction, and the thickness from the front surface 2a to the back surface 2b differs depending on the intended use. However, the thickness is usually 10 μm or more. When the thickness is less than 10 μm, there may be a problem in the followability and durability with respect to the height variation of the electrode to be inspected and the level difference. In addition, when the thickness is increased, the sheet may have a rod shape instead of the sheet shape, but the present invention includes such a shape.

  Moreover, as shown in FIG. 4, the edge part of the conductive layer 6 is exposed from the surface 2a and the back surface 2b which comprise the both end surfaces of thickness direction. Thereby, it can energize reliably only by making the anisotropic conductive sheet 2 contact a to-be-connected electrode.

  Here, when manufacturing the anisotropic conductive sheet 2, first, a plurality of conductive layers 6 are arranged at intervals on at least one surface of the sheet 4 (arrangement step) (see FIG. 3) The sheet 4 is wound in the direction in which the layer 6 is disposed (winding step). And as shown in FIG. 5, the anisotropically conductive sheet 2 is completed by cut | disconnecting wound body 2 'which is the wound sheet | seat 4 with the cutter 10 in the direction orthogonal to the axial direction of winding ( Slicing process). In addition, you may cut the anisotropic conductive sheet 2 cut out in the disk shape into a rectangular shape and another shape after a thin cutting process as needed (processing process). By making the anisotropic conductive sheet 2 rectangular as described above, the anisotropic conductive sheet 2 may be easier to use than in the case where the anisotropic conductive sheet 2 remains circular.

  Various publicly known methods can be applied as a method of disposing a plurality of conductive layers 6 made of a thin film containing a conductive material at an interval on at least one surface of a sheet 4 made of an elastic polymer material. For example, a plurality of conductive layers 6 are formed at a desired thickness, width, and interval by printing and curing a paste containing a conductive material such as a silver paste on at least one surface of a sheet 4 made of an elastic polymer material. Can be formed and arranged on the surface of the sheet 4. In addition, as a paste containing such an electroconductive substance, the thing which the electrically conductive layer 6 formed by hardening | curing, such as the paste for stretchable PCBs developed in recent years has a stretching property is preferable.

  Also, a plurality of conductive layers 6 are formed on the surface of the sheet 4 at a desired thickness, width and interval by sputtering or vapor-depositing a conductive material on at least one surface of the sheet 4 made of an elastic polymer material. Can be arranged.

  Furthermore, after forming a plurality of conductive layers 6 with a desired thickness, width, and interval by plating on a metal plate or metal foil, the plating layer is transferred to at least one surface of the sheet 4 made of an elastic polymer material. The conductive layer 6 can be disposed.

  In the present invention, the width of the conductive layer 6 disposed on at least one surface of the sheet 4 made of an elastic polymer substance is usually 1 μm or more and 100 μm or less, preferably 2 μm or more and 50 μm or less. When the width of the conductive layer 6 exceeds 100 μm, a short circuit may occur between adjacent electrodes when the electrode pitch of the connected electrodes is reduced. On the other hand, when the thickness is less than 1 μm, although depending on the thickness of the conductive layer 6, the contact area with the electrode to be connected becomes too small and the contact resistance value increases, and desired electrical characteristics may not be obtained.

  The thickness of the conductive layer 6 is usually 0.1 μm or more and 30 μm or less, preferably 0.5 μm or more and 15 μm or less. When the thickness of the conductive layer 6 exceeds 30 μm, although depending on the width of the conductive layer 6, the rigidity of the conductive layer 6 is increased and the load for contact with the connected electrode is increased, resulting in damage to the test object. I might let you. On the other hand, when the thickness is less than 0.1 μm, although depending on the width of the conductive layer 6, the contact area with the connected electrode becomes too small and the contact resistance value becomes large, and desired electrical characteristics may not be obtained. .

  In this way, by setting the width and thickness of the conductive layer 6 within a predetermined range, the flexibility of the anisotropic conductive sheet 2 is ensured, and it is possible to follow variations in height and steps of the connected electrode with a low load. Moreover, the electrical resistance value and contact resistance value of the conductive layer 6 can be lowered.

  Furthermore, the conductive layer 6 is disposed on at least one surface of the sheet 4 made of an elastic polymer substance at an interval of usually 30 μm or less, preferably 20 μm or less. When the interval exceeds 30 μm, a short circuit may occur between adjacent electrodes when the pitch of the connected electrodes is reduced. On the other hand, the lower limit is not particularly limited as long as no short circuit occurs between the conductive layers 6, but it is usually 0.5 μm, preferably 1 μm. Smaller intervals can make manufacturing difficult and expensive.

  In the present invention, the conductive material that can be used for the conductive layer 6 is not particularly limited as long as the effects of the present invention are not impaired. For example, as a material blended in a paste, a single substance or a mixed metal of two or more kinds is used. Compound particles or fillers, carbon black, carbon nanotubes, carbon fillers, coated particles or coated fillers formed by coating an inorganic or organic material with a conductive substance, or a mixture of these may be used. In the case of a metal compound, the conductive layer 6 can be formed by sputtering, vapor deposition, or plating. In this case, you may use individually or in combination of multiple types.

  Of the metal compounds, gold, silver, copper, platinum, tin, palladium, rhodium or an alloy thereof is preferable because of low electric resistance. In addition, when a high hardness metal such as nickel or tungsten and a metal with low electrical resistance such as gold are stacked together, even if the electrode to be connected is contaminated with an oxide or the like, the coating may be broken and contacted. It may be preferable.

  In the present invention, the thickness of the sheet 4 made of an elastic polymer substance is generally unspecified because it is related to the thickness of the conductive layer 6, but is usually 1 μm to 100 μm, preferably 3 μm to 50 μm.

  When the thickness of the sheet 4 exceeds 100 μm, the interval between the conductive layers 6 increases in the thickness direction of the wound sheet 4, and when the electrode pitch of the electrodes to be connected is decreased, all the electrodes cannot be connected together. Sometimes. On the other hand, when the thickness is less than 1 μm, the strength of the sheet 4 may be insufficient and winding may be difficult.

  In the present invention, examples of the elastic polymer material used for the sheet 4 made of the elastic polymer material include silicone rubber, urethane rubber, fluorine rubber, isoprene rubber, butadiene rubber, butyl rubber, acrylonitrile-butadiene rubber, and styrene-butadiene rubber. And publicly known ones such as styrene-propylene rubber, ethylene-propylene rubber, and natural rubber.

  Among these, a thermosetting silicone rubber or a thermosetting urethane rubber that is liquid at normal temperature and is cured by heating to become a solid rubber can easily obtain the sheet 4 of any thickness, Since the curing (solidification) can be controlled in the middle, the sheets 4 wound by reheating after the winding process can be bonded together, which is preferable because the manufacturing process of the anisotropic conductive sheet 2 can be simplified.

Furthermore, the thermosetting silicone rubber is more preferable because the anisotropically conductive sheet 2 to be obtained is excellent in heat resistance, and the deterioration of the conductive layer 6 is reduced and the durability is excellent.
When the sheet 4 made of a polymer material on which the conductive layer 6 is disposed is wound in the direction in which the conductive layer 6 is disposed, an adhesive layer or an adhesive layer may be provided on at least one surface of the sheet 4. Further, after winding, the wound body 2 'may be dipped in the liquid elastic polymer substance 15 and cured (curing step). Immersion may be performed only on at least one end of the wound body 2 ′, or the entire wound body 2 ′ may be immersed as shown in FIG. When such a method is used, the elastic polymer material permeates between the sheets 4 made of the wound polymer material to bond the sheets 4 together, or the entire wound body 2 'is elastic polymer material. Can be prevented and the sheet 4 can be prevented from peeling off, so that the durability of the anisotropic conductive sheet of the present invention can be improved.

  In producing the anisotropic conductive sheet 2 by cutting the wound body 2 ′ in a direction perpendicular to the axial direction of the winding, a slicer may be used in addition to the cutter 10. As the cutter 10 and the slicer, a publicly known one is sufficient.

  Furthermore, the anisotropically conductive sheet 2 cut out may be attached to a support body made of a rigid body as necessary. By providing such a support, workability during use may be improved.

  The material of the support is not particularly limited as long as the effects of the present invention are not impaired, but thermoplastic resins such as styrene resins such as vinyl chloride resins, acrylic resins, ABS resins, cyclic olefin resins, polyurethane resins. , Polyethylene resin, polypropylene resin, polyester resin, polycarbonate resin, fluororesin, polyphenylene sulfide resin, or thermosetting resin such as phenol resin, urea resin, melamine resin, unsaturated polyester resin, epoxy resin, polyimide resin, BT resin, etc. A known hard resin, or a plate or film made of a composition in which a filler or fiber made of an inorganic substance such as glass or ceramic is blended with these resins can be used.

Moreover, metal foils, such as copper foil, may be arrange | positioned on these surfaces. Furthermore, nonmagnetic metals such as glass, ceramics, stainless steel, and aluminum can also be used.
Of these, cyclic olefin-based resins, epoxy resins, polyimide resins, BT resins, or plates or films made of a composition in which fillers or fibers made of inorganic substances such as glass or ceramic are blended, are heat resistant or polymerized. It is excellent in adhesion to an elastic body, easy to process and easy to handle.

<Example 1>
After coating, exposing and developing a resist for plating (THB-151N manufactured by JSR Co., Ltd.) on a silicon wafer, a gold linear pattern having a width of 7 μm and a thickness of 2 μm was provided at an interval of 3 μm by electrolytic plating. Next, the resist is removed, and a liquid silicone rubber (manufactured by Shin-Etsu Chemical Co., Ltd .: KE-1950-70 (A / B)) is applied at a thickness of 15 μm so as to cover the gold pattern, and heated at 150 ° C. for 1 hour. And cured. Thereafter, a liquid silicone rubber (manufactured by Shin-Etsu Chemical Co., Ltd .: KE-1950-70 (A / B)) is applied to the surface of the cured rubber with a thickness of 5 μm, and the gold pattern becomes perpendicular to the winding direction. As described above, the cured silicone rubber layer was wound while being peeled from the silicon wafer.

The obtained wound body was re-cured by heating at 150 ° C. for 4 hours, and then cut (sliced) using a safety razor blade to obtain a substantially circular anisotropic conductive sheet having a thickness of 100 μm. FIG. 7 shows a partial photograph of the obtained anisotropic conductive sheet.
According to the invention according to this embodiment, it is possible to provide the anisotropic conductive sheet 2 and the method for manufacturing the anisotropic conductive sheet 2 that can dispose the conductive layer 6 with high density and are easy to handle. .

<Example 2>
Surface of sheet of liquid silicone rubber (manufactured by Shin-Etsu Chemical Co., Ltd .: KE-1950-70 (A / B)) coated on a mirror-finished iron plate with a thickness of 20 μm and cured by heating at 150 ° C. for 4 hours. In addition, a gold linear pattern having a width of 5 μm and a thickness of 1 μm was provided at an interval of 5 μm by vapor deposition. Thereafter, the cured silicone rubber layer was wound while being peeled from the iron plate so that the gold pattern was perpendicular to the winding direction.

Soaking in liquid silicone rubber (manufactured by Shin-Etsu Chemical Co., Ltd .: KE-1950-10 (A / B)) from one end of the obtained wound body to a height until the other end is substantially hidden, Thereafter, it was cured by heating at 150 ° C. for 4 hours. Next, it was cut (sliced) using a safety razor blade, and the silicone rubber layer outside the wound body was cut and roughly removed to obtain a substantially circular anisotropic conductive sheet having a thickness of 500 μm.
According to the invention according to this embodiment, it is possible to provide the anisotropic conductive sheet 2 and the method for manufacturing the anisotropic conductive sheet 2 that can dispose the conductive layer 6 with high density and are easy to handle. .

2 anisotropic conductive sheet 2 'wound body 2a anisotropic conductive sheet surface 2b anisotropic conductive sheet back surface 4 sheet 6 conductive layer 10 cutter 15 liquid elastic polymer substance

Claims (6)

An anisotropic structure in which a sheet made of an elastic polymer material is wound, and a plurality of conductive layers made of a thin film containing a conductive material are continuously arranged on at least one surface of the sheet at intervals in the winding direction of the sheet A conductive sheet,
The anisotropic conductive sheet has a thickness direction in the axial direction of winding,
An anisotropic conductive sheet characterized in that end portions of the conductive layer are exposed from the front and back surfaces forming both end faces in the thickness direction.   2. The conductive layer is a thin film having a width of 1 μm to 100 μm and a thickness of 0.1 μm to 30 μm, and is disposed in the winding direction at an interval of 1 μm to 30 μm. The anisotropic conductive sheet described.   The anisotropic conductive sheet according to claim 1 or 2, wherein the thickness of the sheet is 1 µm or more and 100 µm or less.   The anisotropic conductive sheet according to any one of claims 1 to 3, wherein the elastic polymer substance is silicone rubber. It is a manufacturing method of the anisotropic conductive sheet according to any one of claims 1 to 4,
An arrangement step of arranging a plurality of conductive layers made of a thin film containing a conductive material at intervals on at least one surface of a sheet made of an elastic polymer material, and winding the sheet in the direction in which the conductive layer is arranged Winding process to
A method for producing an anisotropic conductive sheet, comprising: a thin slicing step of cutting the wound sheet in a direction perpendicular to the axial direction of the winding to create an anisotropic conductive sheet.   6. The anisotropic conductive sheet according to claim 5, further comprising a curing step of immersing the wound sheet in a liquid polymer material and then curing the liquid polymer material after the winding step. Production method.