JP6323982B2 - Electronic component having stretchable substrate and method for manufacturing the same - Google Patents

Description

The present invention relates to an electronic component including a stretchable substrate and a manufacturing method thereof .

In recent years, a technical field called stretchable electronics or stretchable electronics has attracted attention. In this technical field, a plurality of elements are mounted on a substrate having elasticity, and these are connected by wiring to produce an electronic component / equipment.
In the conventional flexible substrate, even if the substrate itself is flexible, it does not have elasticity, so it is placed in close contact with the human body and covers the surface of an object with a complicated shape, such as to follow the movement of the human body. It was difficult to use for the use arrange | positioned.

  In order to realize stretchable electronics, a stretchable substrate and a stretchable wiring for connecting elements mounted on the substrate are required. Examples of the stretchable substrate include a film or sheet made of an elastomer, and a method of forming a stretchable wiring is also known. However, an element having stretchability has not been known so far, and when the element is mounted on a stretchable substrate made of an elastomer and connected by a stretchable wiring, the device is destroyed when the substrate is stretched.

In order to prevent this, there is an elastically deformable integrated circuit device in which a plurality of non-stretchable islands are arranged on the surface of a substrate, circuit elements are mounted on these islands, and these circuit elements are connected by connecting portions. It has been proposed (see, for example, Patent Document 1).
However, since each island protrudes from the substrate surface in the structure according to the prior art, if the wiring is formed so as to straddle the boundary between the island and the substrate surface, a part of the wiring is formed at the step portion between the island and the substrate surface. Are formed in the vertical direction. Therefore, there is a problem that the wiring is easily disconnected at the step portion while the substrate is repeatedly expanded and contracted.

Special table 2009-533839

  The present invention has been made in view of the above circumstances, and provides an elastic substrate that prevents destruction of elements and disconnection of wiring when the substrate is expanded and contracted, a manufacturing method thereof, and an electronic component including the elastic substrate. Objective.

In order to solve the above problems, a first aspect of the present invention includes a base material made of a stretchable material and an island made of a material having a Young's modulus larger than that of the base material, Provided is a stretchable substrate characterized by being embedded in the base material in a state of being exposed on one main surface of the base material.
In the stretchable substrate configured as described above, the island is embedded in the base material so as to be flat without forming a step at the boundary between the surface and one main surface of the base material. be able to.

An elastomer can be used as the stretchable material. Silicone rubber can be used as the elastomer.
As a material having a Young's modulus larger than that of the base material, a material containing the same elastomer as the main constituent of the elastomer constituting the base material can be used. In this case, as a material having a Young's modulus larger than that of the base material, a material obtained by adding a filler to the same elastomer as that constituting the base material can be used. Silica powder can be used as the filler.

Or the elastomer prepared using the crosslinking agent or hardening | curing agent of the compounding ratio larger than the case where it uses for the elastomer which comprises the said base material as a material with a larger Young's modulus than the said base material can be used.
A second aspect of the present invention is a method for manufacturing the stretchable substrate according to the first aspect of the present invention described above, the step of forming an island made of a material having a Young's modulus larger than that of the base material, There is provided a method for producing a stretchable substrate, comprising a step of embedding the island in the base material so as to be exposed on one main surface of the base material made of a stretchable material.

In the elastic substrate manufacturing method configured as described above, the step of forming an island on the base substrate and embedding the island in the base material is performed, and the liquid base material is poured around the base substrate on which the island is formed. After molding, curing can be performed, and then the base substrate is removed so that the island is exposed.
An island can be formed on the base substrate by printing. In this case, metal mask printing or screen printing can be used as printing.

According to a third aspect of the present invention, there is provided an electronic component comprising an element and / or a wiring formed on the stretchable substrate according to the first aspect of the present invention described above.
In the electronic component configured as described above, an element can be formed on an island. Further, the wiring can be formed so as to straddle the boundary between the island and the base material. In this case, a stretchable wiring can be used as the wiring.

  ADVANTAGE OF THE INVENTION According to this invention, the electronic component provided with the elastic substrate which prevented the destruction of the element at the time of expansion-contraction and the disconnection of wiring, its manufacturing method, and an elastic substrate is provided.

It is sectional drawing which shows the elastic board | substrate which concerns on one Embodiment of this invention. It is sectional drawing which shows the electronic component which concerns on other embodiment of this invention. It is sectional drawing which shows the manufacturing method of the elastic board | substrate which concerns on other embodiment of this invention in order of a process.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing a stretchable substrate 1 according to an embodiment of the present invention. A stretchable substrate 1 shown in FIG. 1 includes a base material 2 and islands 3a and 3b embedded in the surface thereof. The islands 3a and 3b are embedded so that the upper surface of the islands 3a and 3b is exposed on one main surface of the substrate 2, and the upper surfaces of the islands 3a and 3b and the one main surface of the substrate 2 are not stepped. Preferably it is. It should be noted that the presence of a slight level difference is allowed as long as there is no influence on the connection of the wirings, not only when there is no level difference.

The substrate 2 is made of a stretchable material, and an elastomer can be used as such a material. Examples of the elastomer include, but are not limited to, silicone rubber, urethane rubber, fluororubber, natural rubber, acrylic rubber, and thermoplastic elastomer.
The material constituting the islands 3a and 3b is not particularly limited as long as it is a material having a Young's modulus larger than that of the material constituting the substrate 2. An elastomer, resin, ceramic, or the like can be used. For applications that may have electrical conductivity, it is also possible to use metals.

  Moreover, it is preferable that the material which comprises the islands 3a and 3b has a Young's modulus of 2 times or more of the Young's modulus of the material which comprises the base material 2. Specifically, the elastic material constituting the substrate 2 usually has a Young's modulus of 0.1 to 10 MPa, and the material constituting the islands 3a and 3b is a Young's modulus of 0.2 MPa or more. It is preferable to have a rate.

  In addition, it is preferable to use what has the same elastomer as the elastomer which comprises the base material 2 as a main component as a material which comprises the islands 3a and 3b. By doing so, the adhesion between the base material 2 and the islands 3a and 3b can be improved, and the islands 3a and 3b can be prevented from peeling off from the base material 2 even when the substrate 1 is repeatedly expanded and contracted. it can.

  As the main component of the same elastomer as the elastomer constituting the substrate 2, a material obtained by adding a filler to the same elastomer as that constituting the substrate 2 can be used. By adding the filler in this way, the Young's modulus can be increased while the main component is the same as the elastomer constituting the substrate 2. Examples of the filler include, but are not limited to, silica powder, carbon black, and alumina powder. The addition amount of the filler may be appropriately selected within a range in which a desired Young's modulus can be obtained, but is usually 1 to 60% by weight with respect to the total weight of the material of the island.

  As the main component of the same elastomer as that constituting the base material 2, those prepared by using a crosslinking agent or a curing agent having a higher blending ratio than that used for the elastomer constituting the base material 2 can be used. . Thus, the Young's modulus can be increased also by increasing the compounding ratio of the crosslinking agent or curing agent. In this case, the blending ratio of the elastomer crosslinking agent or curing agent of the material constituting the islands 3a and 3b may be appropriately selected within a range where a desired Young's modulus can be obtained.

  In FIG. 1, two islands are embedded in the base material 2, but the number of islands is not particularly limited and can be selected as necessary. Further, the arrangement of islands can be selected as necessary. The shape, size, and thickness of the island can be arbitrarily selected as necessary.

  FIG. 2 shows an electronic component configured using the stretchable substrate 1 shown in FIG. 1 described above. In the electronic component 4 shown in FIG. 2, elements 5 a and 5 b are mounted on the islands 3 a and 3 b, respectively, and the elements 5 a and 5 b are connected by wiring 6. As the wiring 6, it is preferable to use a stretchable wiring. Examples of the stretchable wiring include those made of a resin containing conductive particles made of carbon, metal, or the like.

  In the electronic component configured as described above, even if the base material 2 expands and contracts, the islands 3a and 3b embedded therein have a higher Young's modulus than the base material 2, so that the base material 2 can follow the expansion and contraction. Therefore, the elements 5a and 5b mounted on the islands 3a and 3b are not destroyed. In addition, since there is no step at the boundary between the islands 3a and 3b and the surface of the base material 2 or it is sufficiently small, the wiring 6 is not disconnected by expansion and contraction on the boundary between the island and the base material. Further, since the islands 3a and 3b are embedded in the base material 2, even if the base material 2 is repeatedly expanded and contracted, the islands 3a and 3b are not peeled off from the base material 2, and such an elastic substrate itself. High strength can be ensured as compared with conventional stretchable substrates.

Next, the manufacturing method of the elastic substrate demonstrated above is demonstrated with reference to drawings.
FIG. 3 is a cross-sectional view showing a method of manufacturing a stretchable substrate according to another embodiment of the present invention in the order of steps.
First, as shown in FIG. 3A, an island 13 is formed on the base 10. Although FIG. 3 shows an example in which one island is formed, as described above, the number of islands and the arrangement thereof are arbitrary and can be appropriately selected.
The material of the foundation | substrate 10 is not specifically limited, The island 13 should just be formed on it, For example, a glass substrate, a metal substrate, a resin substrate etc. can be used.

  The material of the island 13 can use what was mentioned above. The formation method of the island 13 is not particularly limited. For example, the island 13 can be formed by a method in which an island material is printed and then cured. As the printing method, any printing method can be selected according to the characteristics of the material. For example, a metal mask printing method using a metal mask and a stencil printing method typified by screen printing have an advantage that it is easy to increase the thickness of the island because thick film printing is possible. Note that the thickness of the metal mask in the metal mask printing method needs to be set according to the thickness of the island. As a printing method, plateless printing using a dispenser, an ink jet, or the like can be used.

The island 13 can also be formed by attaching an island 13 separately formed in advance to the surface of the base 10 by a method such as putting an island material into a mold and curing it, regardless of the printing method.
Next, as shown in FIG. 3 (b), the base 10 on which the islands 13 are formed is accommodated in a container 20, and a liquid substrate material 22 is poured therein. As the base material 22, a liquid elastomer before curing of the elastomer constituting the base 2 described above can be used. Thereafter, the liquid elastomer is cured by standing or heating at room temperature.

Next, unnecessary portions of the cured elastomer are removed and peeled off from the base 10 to complete the stretchable substrate 11 in which the islands 13 are embedded in the base 12 as shown in FIG.
In the above embodiment, a liquid base material, for example, a liquid elastomer, is used and injected into a container containing the base 10 on which the islands 13 are formed. If necessary, an elastomer other than the liquid elastomer is used. It is also possible to use it. For example, a stretchable substrate in which islands are embedded in a base material can also be obtained by press-fitting a raw material elastomer containing an island and a crosslinking agent into a mold and performing a vulcanization molding process.

Hereinafter, the present invention will be described more specifically by showing examples of the present invention.
Example 1
First, an island material is prepared. The island material was made of a liquid elastomer containing a filler, and the following silica powder was used as the filler and the following liquid silicone rubber was used as the liquid elastomer.

Liquid silicone rubber: Sylgard 184 (trade name, manufactured by Toray Dow Corning)
Silica powder: Carplex CS-7 (trade name, manufactured by DSL Japan)
Sylgard 184 is a two-component liquid silicone rubber composed of a main agent and a curing agent, and curing proceeds by mixing the main agent and the curing agent. Before curing, it is liquid at room temperature, and becomes a silicone rubber having elasticity upon curing.

The island material was prepared by mixing the main component of Sylgard 184, the curing agent, and silica powder. The compounding ratio was main agent: curing agent = 10: 1 (weight ratio), and the ratio of silica powder in the mixture was 40% by weight.
As shown in FIG. 3A, the island material prepared as described above was printed almost at the center of the glass substrate 10 having a size of 4 × 4 cm to form one island 13. The printing method was printing using a metal mask having a thickness of 0.2 mm, and the shape of the island 13 was a circle having a diameter of 5 mm. A metal mask having a thickness of 0.4 mm may be used, and the shape of the island 13 may be a circle having a diameter of 8 mm, a 5 mm square, or a 8 mm square.

  Next, as shown in FIG. 3B, the glass substrate 10 on which the islands 13 were formed was accommodated in a container 20, and Sylgard 184 was poured therein as a liquid base material 20. Sylgard 184 was mixed such that the main agent: curing agent = 10: 1 (weight ratio), and no silica powder was added. The amount of Sylgard 184 poured was the amount of liquid calculated so that the thickness of the formed substrate was 1 mm.

Next, Sylgard 184 was cured at room temperature or under heating conditions. The Young's modulus of the cured Sylgard 184 was 1.4 MPa. The Young's modulus of the cured silica powder-containing Sylgard 184 constituting the island 13 was 24 MPa.
Thereafter, unnecessary portions of the cured Sylgard 184 were removed and peeled off from the glass substrate 10 to complete the stretchable substrate 11 in which the island 13 was embedded in the base material 12 as shown in FIG. .

  In the stretchable substrate 11 obtained in this way, the island 13 is embedded in the base material 12, so that the island 13 and the surface of the base material 12 have no step and have a flat structure. Even when the element is mounted on the island 13 of the stretchable substrate 11 and the stretchable substrate 11 is stretched, the element is not destroyed. In addition, since the boundary portion between the element mounting surface of the embedded island and the surrounding base material main surface is flat on the elastic substrate surface, even if the elastic substrate is repeatedly expanded and contracted, it straddles the boundary. The formed elastic wiring was never disconnected. Further, since the island 13 and the base material 12 are in close contact with each other, the island 13 did not peel from the base material 12.

Example 2
In Example 1, Sylgard 184 containing silica powder was printed on a glass substrate and cured to form islands 13, but in this example, islands 13 that had been previously molded into chips and cured were made of glass. The island 13 was formed by pasting on the substrate 10.
That is, the same island material as used in Example 1 was poured into a mold, cured by heating, taken out from the mold, and attached to the glass substrate 10.

  Thereafter, Sylgard 184 is poured into the container 20 that accommodates the glass substrate 10 on which the islands 13 are formed in the same procedure as in the first embodiment, is cured, and unnecessary portions of the cured Sylgard 184 are removed. As shown in FIG. 3C, the stretchable substrate 11 in which the island 13 is embedded in the base material 12 was completed.

  In the stretchable substrate 11 obtained in this way, the island 13 is embedded in the base material 12, so that the island 13 and the surface of the base material 12 have no step and have a flat structure. Even when the element is mounted on the island 13 of the stretchable substrate 11 and the stretchable substrate 11 is stretched, the element is not destroyed. In addition, since the boundary portion between the element mounting surface of the embedded island and the surrounding base material main surface is flat on the elastic substrate surface, even if the elastic substrate is repeatedly expanded and contracted, it straddles the boundary. The formed elastic wiring was never disconnected. Further, since the island 13 and the base material 12 are in close contact with each other, the island 13 did not peel from the base material 12.

Example 3
In Example 1, Sylgard 184 to which silica powder was added was used as the island material. However, in this example, silica powder was not added and the blending ratio of the curing agent was increased as compared to Sylgard 184 as the base material. Using Sylgard184, an island 13 having a higher Young's modulus than the base material was formed.

That is, Sylgard 184 with a blending ratio of the main agent and the curing agent = 5: 1 (weight ratio) is used as the island material, and Sylgard 184 with a blending ratio of the main agent and the curing agent = 15: 1 (weight ratio) as the base material. A stretchable substrate was formed in the same procedure as in Example 1 except that was used.
The Young's modulus of the island 13 after curing was 1.5 MPa, and the Young's modulus of the substrate 12 after curing was 0.57 MPa.

  In the stretchable substrate 11 obtained in this way, the island 13 is embedded in the base material 12, so that the island 13 and the surface of the base material 12 have no step and have a flat structure. Even when the element is mounted on the island 13 of the stretchable substrate 11 and the stretchable substrate 11 is stretched, the element is not destroyed. In addition, since the boundary portion between the element mounting surface of the embedded island and the surrounding base material main surface is flat on the elastic substrate surface, even if the elastic substrate is repeatedly expanded and contracted, it straddles the boundary. The formed elastic wiring was never disconnected. Further, since the island 13 and the base material 12 are in close contact with each other, the island 13 did not peel from the base material 12.

DESCRIPTION OF SYMBOLS 1,11 ... Elastic substrate 2,12 ... Base material 3a, 3b, 13 ... Island 4 ... Electronic component 5a, 5a ... Element 6 ... Wiring 10 ... Glass substrate 20 ... Container 22 ... Base material.

Claims (9)

A substrate made of an elastomer, and a first island and a second island made of a material having a Young's modulus greater than that of the substrate selected from the group consisting of an elastomer, a resin, and a ceramic, And a stretchable substrate in which the first and second islands are embedded in the base material, with an upper surface of the second island exposed on one main surface of the base material,
A first element and a second element formed on each of the first and second islands; one end connected to the first element; the other end connected to the second element; A stretchable wiring formed across the first island and the base material and the second island and the base material on one island surface, the base material surface, and the second island surface ;
The elastomer is silicone rubber;
An electronic component characterized in that a material having a Young's modulus greater than that of the base material contains, as a main component, the same elastomer as that constituting the base material .   The first and second islands are embedded in the base material so as to be flat without forming a step at the boundary between the surface and one main surface of the base material. The electronic component according to claim 1. Electronic component according to claim 1, wherein the material having a high Young's modulus than the base material, characterized by comprising a filler in the same elastomer and elastomer constituting the substrate. The electronic component according to claim 3 , wherein the filler is silica powder. A material having a large Young's modulus than the base material, to claim 1, wherein those prepared using a crosslinking agent or curing agent of more compounding ratios than was used in the elastomer forming the substrate The electronic component described. A method of manufacturing an electronic component according to any one of claims 1 to 5
Forming first and second islands made of a material having a Young's modulus greater than that of the substrate selected from the group consisting of elastomers, resins, and ceramics;
Embedding the first and second islands in the base so as to be exposed on one main surface of the base made of elastomer;
Forming a first element and a second element on the first and second islands, respectively;
One end is connected to the first element, the other end is connected to the second element, and the first island surface, the base material surface, and the second island surface have the first island and The manufacturing method of an electronic component characterized by comprising the process of forming a stretchable wiring straddling a base material and a said 2nd island, and a base material. The first and second islands are formed on a base substrate, and the step of embedding the first and second islands in the base material is performed around the base substrate on which the first and second islands are formed. 7. The electronic component according to claim 6 , wherein the liquid base material is cast and then cured, and then the base substrate is removed so that the first and second islands are exposed. Production method. It said first and second islands formed on the base substrate, the method for manufacturing the electronic component according to claim 6 or 7, characterized in that the printing. The method of manufacturing an electronic component according to claim 8 , wherein the printing is metal mask printing or screen printing.

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