JP7067011B2 - Wiring board and manufacturing method of wiring board - Google Patents

Description

An embodiment of the present disclosure relates to a wiring board comprising a substrate and a support substrate provided with wiring joined to the substrate and connected to electronic components. Moreover, the embodiment of this disclosure relates to the manufacturing method of the wiring board.

In recent years, research has been conducted on electronic devices having deformability such as elasticity. For example, Patent Document 1 discloses a wiring board provided with a substrate and wiring provided on the substrate and having elasticity. Patent Document 1 employs a manufacturing method in which a circuit is provided on a pre-stretched substrate, the circuit is formed, and then the substrate is relaxed. Patent Document 1 intends to operate the thin film transistor on the substrate satisfactorily in both the extended state and the relaxed state of the substrate.

Japanese Unexamined Patent Publication No. 2007-281406

The wiring board includes not only a part having resistance to deformation such as expansion and contraction but also a part easily damaged due to deformation. For this reason, if the circuit is provided on the board in the stretched state in advance, problems such as damage to the wiring board are likely to occur.

It is an object of the present disclosure to provide a wiring board and a method for manufacturing a wiring board that can effectively solve such a problem.

One embodiment of the present disclosure is a stretchable substrate including a first surface and a second surface located on the opposite side of the first surface, and is joined to the substrate from the first surface side of the substrate. A support substrate having an elastic coefficient higher than that of the substrate, and wiring provided on the support substrate so as to be connected to electrodes of electronic components mounted on the support substrate. A wiring having a bellows-shaped portion in which peaks and valleys in the normal direction of one surface repeatedly appear along the in-plane direction of the first surface of the substrate, and stress generated in the substrate due to expansion and contraction are supported by the substrate. It is a wiring board provided with a stress adjusting mechanism provided in a part of the board so as to suppress transmission to the board.

In the wiring board according to the embodiment of the present disclosure, the stress adjusting mechanism is the first of the boards so as to overlap the electronic components mounted on the support board when viewed along the normal direction of the first surface. It overlaps the first reinforcing member, which is located on the surface and has an elastic coefficient higher than the elastic coefficient of the substrate, and the electronic component mounted on the support substrate when viewed along the normal direction of the first surface. A second reinforcing member, which is located on the second surface of the substrate and has an elastic coefficient higher than that of the substrate, may be provided. In this case, the thickness of the portion of the substrate that overlaps with the first reinforcing member and the second reinforcing member when viewed along the normal direction of the first surface is the thickness of the first surface of the substrate. When viewed along the normal direction, the thickness may be smaller than the thickness of the portion that does not overlap with the first reinforcing member or the second reinforcing member. The first reinforcing member or the second reinforcing member may include a metal layer.

In the wiring board according to the embodiment of the present disclosure, the stress adjusting mechanism is the second of the board so as to overlap the electronic components mounted on the support board when viewed along the normal direction of the first surface. It may be provided with a plurality of slits formed on the surface. In this case, the depth of the slit may be 30% or more of the thickness of the substrate.

In the wiring board according to the embodiment of the present disclosure, the amplitude of the bellows-shaped portion of the wiring may be 1 μm or more.

In the wiring board according to the embodiment of the present disclosure, the board may contain silicone rubber.

In the wiring board according to the embodiment of the present disclosure, the wiring may contain a plurality of conductive particles.

The wiring board according to one embodiment of the present disclosure may further include an electronic component that is located on the support board and has electrodes electrically connected to the wiring.

One embodiment of the present disclosure is a method of manufacturing a wiring board, which includes a first surface and a second surface located on the opposite side of the first surface, and applies tensile stress to the elastic substrate to apply the above-mentioned. A second reinforcing member having an elongation step of extending the substrate and a first reinforcing member having an elastic coefficient higher than that of the substrate is provided on the first surface of the substrate and has an elastic coefficient higher than that of the substrate. A step of providing a reinforcing member on the second surface of the substrate, and a wiring that is a support substrate having an elastic coefficient higher than the elastic coefficient of the substrate and is connected to an electrode of an electronic component mounted on the support substrate. The support substrate provided with the above is provided with a joining step of joining the stretched substrate to the substrate from the first surface side and a shrinkage step of removing the tensile stress from the substrate, and the joining step is the first. After the electronic components mounted on the support substrate are overlapped with the first reinforcing member and the second reinforcing member when viewed along the normal direction of the surface, and the tensile stress is removed from the substrate. The portions of the wiring that do not overlap with the first reinforcing member and the second reinforcing member when viewed along the normal direction of the first surface are peaks and valleys in the normal direction of the first surface. This is a method for manufacturing a wiring board, which has a bellows-shaped portion in which the portion repeatedly appears along the in-plane direction of the first surface.

One embodiment of the present disclosure is a method of manufacturing a wiring board, which includes a first surface and a second surface located on the opposite side of the first surface, and applies tensile stress to the stretchable substrate to apply the above-mentioned A support substrate having an elongation step for extending the substrate and a support substrate having an elastic coefficient higher than the elastic coefficient of the substrate and provided with wiring connected to electrodes of electronic components mounted on the support substrate. A joining step of joining the stretched substrate from the first surface side and a shrinking step of removing the tensile stress from the substrate are provided, and the substrate is carried out between the joining step and the shrinking step. Of the above, the substrate is further provided with a slit forming step of forming a plurality of slits on the second surface of the portion overlapping with the electronic component mounted on the support substrate when viewed along the normal direction of the first surface. After the tensile stress is removed from the above, the portion of the wiring that does not overlap with the slit when viewed along the normal direction of the first surface is a mountain portion and a valley in the normal direction of the first surface. This is a method for manufacturing a wiring board, which has a bellows-shaped portion in which portions repeatedly appear along the in-plane direction of the first surface.

In the method for manufacturing a wiring board according to an embodiment of the present disclosure, the depth of the slit may be 30% or more of the thickness of the board.

According to the embodiment of the present disclosure, it is possible to suppress the occurrence of a defect in the wiring board due to the expansion and contraction of the substrate.

It is sectional drawing which shows the wiring board which concerns on one Embodiment. It is a top view which shows the wiring board which concerns on one Embodiment. It is sectional drawing which enlarges and shows an example of the wiring of the wiring board shown in FIG. 1 and the component around it. FIG. 3 is an enlarged cross-sectional view showing other examples of the wiring of the wiring board shown in FIG. 1 and other components around the wiring board. It is a figure for demonstrating the manufacturing method of the wiring board shown in FIG. It is sectional drawing which shows the wiring board which concerns on 1st modification. It is a bottom view which shows the wiring board which concerns on the 1st modification. FIG. 6 is an enlarged cross-sectional view showing an example of the wiring of the wiring board shown in FIG. 6 and its peripheral components. It is a figure for demonstrating the manufacturing method of the wiring board shown in FIG.

Hereinafter, the configuration of the wiring board and the manufacturing method thereof according to the embodiment of the present disclosure will be described in detail with reference to the drawings. It should be noted that the embodiments shown below are examples of the embodiments of the present disclosure, and the present disclosure is not construed as being limited to these embodiments. Further, in the present specification, terms such as "board", "base material", "sheet" and "film" are not distinguished from each other based only on the difference in names. For example, "substrate" is a concept that includes a base material, a member that may be called a sheet or a film. Furthermore, the terms such as "parallel" and "orthogonal" and the values of length and angle used in the present specification to specify the shape and geometric conditions and their degrees are bound by a strict meaning. Instead, the interpretation shall be made to include the range in which similar functions can be expected. Further, in the drawings referred to in the present embodiment, the same parts or parts having similar functions may be designated by the same reference numerals or similar reference numerals, and the repeated description thereof may be omitted. Further, the dimensional ratio of the drawing may differ from the actual ratio for convenience of explanation, or a part of the configuration may be omitted from the drawing.

Hereinafter, an embodiment of the present disclosure will be described with reference to FIGS. 1 to 5.

(Wiring board)
First, the wiring board 10 according to the present embodiment will be described. 1 and 2 are a cross-sectional view and a plan view showing the wiring board 10, respectively. The cross-sectional view shown in FIG. 1 is a view when the wiring board 10 of FIG. 2 is cut along the lines AA.

The wiring board 10 shown in FIG. 1 includes a board 20, a stress adjusting mechanism 30, a support board 40, an electronic component 51, and a wiring 52. Hereinafter, each component of the wiring board 10 will be described.

〔substrate〕
The substrate 20 is a plate-shaped member configured to have elasticity. The substrate 20 includes a first surface 21 located on the side of the electronic component 51 and the wiring 52, and a second surface 22 located on the opposite side of the first surface 21. The thickness of the substrate 20 is, for example, 10 mm or less, more preferably 1 mm or less. By reducing the thickness of the substrate 20, the force required for expansion and contraction of the substrate 20 can be reduced. Further, by reducing the thickness of the substrate 20, the thickness of the entire product using the wiring board 10 can be reduced. Thereby, for example, when the product using the wiring board 10 is a sensor attached to a part of the body such as a human arm, the wearing feeling can be reduced. The thickness of the substrate 20 may be 10 μm or more.

As an example of the parameter representing the elasticity of the substrate 20, the elastic modulus of the substrate 20 can be mentioned. The elastic modulus of the substrate 20 is, for example, 10 MPa or less, more preferably 1 MPa or less. By using the substrate 20 having such an elastic modulus, the entire wiring board 10 can be made elastic. In the following description, the elastic modulus of the substrate 20 is also referred to as a first elastic modulus. The first elastic modulus of the substrate 20 may be 1 kPa or more.

As a method of calculating the first elastic modulus of the substrate 20, a method of carrying out a tensile test using a sample of the substrate 20 can be adopted. As a method of preparing a sample of the substrate 20, a method of extracting a part of the substrate 20 from the wiring board 10 as a sample and a method of extracting a part of the substrate 20 before forming the wiring board 10 as a sample can be considered. Another method for calculating the first elastic modulus of the substrate 20 is to analyze the materials constituting the substrate 20 and calculate the first elastic modulus of the substrate 20 based on the existing database of materials. It can also be adopted.

As another example of the parameter representing the elasticity of the substrate 20, the bending rigidity of the substrate 20 can be mentioned. The flexural rigidity is the product of the moment of inertia of area of the target member and the elastic modulus of the material constituting the target member, and the unit is N · m ² or Pa · m ⁴ . The moment of inertia of area of the substrate 20 is calculated based on the cross section when the substrate 20 is cut by a plane orthogonal to the expansion / contraction direction of the wiring board 10. In the following description, the bending rigidity of the substrate 20 is also referred to as a first bending rigidity.

Examples of the material constituting the substrate 20 include thermoplastic elastomers, silicone rubbers, urethane gels, silicon gels and the like. Examples of the thermoplastic elastomer include polyurethane-based elastomers, styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, vinyl chloride-based thermoplastic elastomers, ester-based thermoplastic elastomers, amide-based thermoplastic elastomers, and 1,2-BR-based thermoplastic elastomers. A fluorothermoplastic elastomer or the like can be used. Considering mechanical strength and abrasion resistance, it is preferable to use a urethane-based elastomer. Further, silicone rubber is excellent in heat resistance, chemical resistance, and flame retardancy, and is preferable as a material for the substrate 20.

[Stress adjustment mechanism]
The stress adjusting mechanism 30 is a mechanism provided in a part of the substrate 20 in order to suppress the stress generated in the substrate 20 due to expansion and contraction from being transmitted to the support substrate 40. In the present embodiment, as shown in FIG. 1, the stress adjusting mechanism 30 has a first reinforcing member 31 located on the first surface 21 of the substrate 20 and a second reinforcing member 31 located on the second surface 22 of the substrate 20. A reinforcing member 32 is provided.

Both the first reinforcing member 31 and the second reinforcing member 32 have an elastic modulus larger than the first elastic modulus of the substrate 20. The elastic modulus of the first reinforcing member 31 and the second reinforcing member 32 is, for example, 1 GPa or more, more preferably 10 GPa or more. The elastic modulus of the first reinforcing member 31 and the second reinforcing member 32 may be 100 times or more or 1000 times or more the first elastic modulus of the substrate 20. By providing the substrate 20 with the stress adjusting mechanism 30 including the first reinforcing member 31 and the second reinforcing member 32, the stress generated in the portion of the substrate 20 that overlaps with the stress adjusting mechanism 30 is applied to the support substrate 40 side. It can be suppressed from being transmitted. As a result, it is possible to prevent the portion of the support substrate 40 and the components on the support substrate 40 that overlap with the stress adjusting mechanism 30 from being damaged. In the following description, the elastic modulus of the first reinforcing member 31 and the second reinforcing member 32 is also referred to as a second elastic modulus.

As shown in FIGS. 1 and 2, the stress adjusting mechanism 30 including the first reinforcing member 31 and the second reinforcing member 32 is a support substrate when viewed along the normal direction of the first surface 21 of the substrate 20. It overlaps with the electronic component 51 located on the 40. In this case, the first reinforcing member 31 and the second reinforcing member 32 function to suppress the stress generated in the substrate 20 due to the expansion and contraction from being transmitted to the electronic component 51 on the support substrate 40. As a result, it is possible to prevent the electronic component 51 from being deformed or damaged.

The second elastic modulus of the first reinforcing member 31 and the second reinforcing member 32 may be 500 GPa or less. Further, the second elastic modulus of the first reinforcing member 31 and the second reinforcing member 32 may be 500,000 times or less the first elastic modulus of the substrate 20. The method of calculating the second elastic modulus of the first reinforcing member 31 and the second reinforcing member 32 is the same as that of the substrate 20. Note that "overlapping" means that the two components overlap when viewed along the normal direction of the first surface 21 of the substrate 20. Further, the elastic modulus of the first reinforcing member 31 and the elastic modulus of the second reinforcing member 32 may be the same or different.

Further, the first reinforcing member 31 and the second reinforcing member 32 have a bending rigidity larger than that of the first bending rigidity of the substrate 20. The bending rigidity of the first reinforcing member 31 and the second reinforcing member 32 may be 100 times or more or 1000 times or more the first bending rigidity of the substrate 20. In the following description, the bending rigidity of the first reinforcing member 31 and the second reinforcing member 32 is also referred to as a second bending rigidity.

Examples of the materials constituting the first reinforcing member 31 and the second reinforcing member 32 include a metal layer containing a metal material, a general thermoplastic elastomer, an acrylic type , a urethane type , an epoxy type , a polyester type , and an epoxy type . Examples thereof include oligomers such as vinyl ether type , polyene / thiol type , and silicone type, and polymers. Examples of metal materials include copper, aluminum, stainless steel and the like. The thickness of the first reinforcing member 31 and the second reinforcing member 32 is, for example, 10 μm or more. Among the above-mentioned materials, the metal layer has a high elastic modulus and can be finely processed by etching or the like, which is more preferable.

[Support board]
The support substrate 40 is a plate-shaped member configured to have lower elasticity than the substrate 20. The support substrate 40 includes a second surface 42 located on the substrate 20 side and a first surface 41 located on the opposite side of the second surface 42. In the example shown in FIG. 1, the support substrate 40 supports the electronic component 51 and the wiring 52 on the first surface 41 side thereof. Further, the support substrate 40 is joined to the first surface of the substrate 20 on the second surface 42 side thereof. For example, an adhesive layer 60 containing an adhesive may be provided between the substrate 20 and the support substrate 40. As the material constituting the adhesive layer 60, for example, an acrylic adhesive, a silicone adhesive, or the like can be used. The thickness of the adhesive layer 60 is, for example, 5 μm or more and 200 μm or less. Further, although not shown, the second surface 42 of the support substrate 40 may be bonded to the first surface 21 of the substrate 20 by normal temperature bonding. In this case, the adhesive layer may not be provided between the substrate 20 and the support substrate 40.

As will be described later, when the tensile stress is removed from the substrate 20 joined to the support substrate 40 and the substrate 20 contracts, a bellows-shaped portion is formed on the support substrate 40. The characteristics and dimensions of the support substrate 40 are set so that such a bellows-shaped portion can be easily formed. For example, the support substrate 40 has an elastic modulus larger than that of the first elastic modulus of the substrate 20. In the following description, the elastic modulus of the support substrate 40 is also referred to as a third elastic modulus.

The third elastic modulus of the support substrate 40 is, for example, 100 MPa or more, more preferably 1 GPa or more. The third elastic modulus of the support substrate 40 may be 100 times or more or 1000 times or more the first elastic modulus of the substrate 20. The thickness of the support substrate 40 is, for example, 10 μm or less, more preferably 5 μm or less. By increasing the elastic modulus of the support substrate 40 or reducing the thickness of the support substrate 40, a bellows-shaped portion is likely to be formed on the support substrate 40 as the substrate 20 shrinks. As the material constituting the support substrate 40, for example, polyethylene naphthalate, polyimide, polycarbonate, acrylic resin, polyethylene terephthalate and the like can be used.

The third elastic modulus of the support substrate 40 may be 100 times or less the first elastic modulus of the substrate 20. The method of calculating the third elastic modulus of the support substrate 40 is the same as that of the substrate 20. Further, the thickness of the support substrate 40 may be 500 nm or more.

[Electronic components]
In the example shown in FIG. 1, the electronic component 51 has at least an electrode connected to the wiring 52. The electronic component 51 may be an active component or a passive component. Examples of active components include transistors, LSIs (Large Scale Integration), MEMS (Micro Electro Mechanical Systems), relays, LEDs, OLEDs, light emitting elements such as LCDs, sensors, and the like. Examples of passive components include resistors, capacitors, inductors, piezoelectric elements and the like. Of the above examples of the electronic component 51, the sensor is preferably used. Examples of the sensor include a temperature sensor, a pressure sensor, an optical sensor, a photoelectric sensor, a proximity sensor, a shear force sensor, a biological sensor and the like. Of these sensors, biosensors are particularly preferred. The biological sensor can measure biological information such as heartbeat, pulse, electrocardiogram, blood pressure, body temperature, and blood oxygen concentration. As shown in FIGS. 1 and 2, a plurality of electronic components 51 may be provided on the support substrate 40. Further, as shown in FIG. 1, the electronic component 51 may be covered with a sealing portion 58 made of resin or the like.

〔wiring〕
The wiring 52 is a conductive member connected to the electrodes of the electronic component 51. For example, as shown in FIG. 2, one end and the other end of the wiring 52 are connected to the electrodes of the two electronic components 51, respectively. As shown in FIG. 2, a plurality of wirings 52 may be provided between the two electronic components 51.

As will be described later, when the tensile stress is removed from the substrate 20 joined to the support substrate 40 and the substrate 20 contracts, the wiring 52 is deformed in a bellows shape. In consideration of this point, preferably, the wiring 52 has a structure having resistance to deformation. For example, the wiring 52 has a base material and a plurality of conductive particles dispersed in the base material. In this case, by using a deformable material such as resin as the base material, the wiring 52 can also be deformed according to the expansion and contraction of the substrate 20. Further, the conductivity of the wiring 52 can be maintained by setting the distribution and shape of the conductive particles so that the contact between the plurality of conductive particles is maintained even when the deformation occurs. ..

As a material constituting the base material of the wiring 52, for example, a general thermoplastic elastomer and a thermocurable elastomer can be used, and for example, a styrene-based elastomer, an acrylic-based elastomer, an olefin-based elastomer, a urethane-based elastomer, and a silicone can be used. Rubber, elastomer rubber, fluororubber, nitrile rubber, polybutadiene, polychloroprene and the like can be used. Among them, resins and rubbers containing urethane-based and silicone-based structures are preferably used in terms of their elasticity and durability. Further, as the material constituting the conductive particles of the wiring 52, for example, particles of silver, copper, gold, nickel, palladium, platinum, carbon and the like can be used. Among them, silver particles are preferably used from the viewpoint of price and conductivity.

The thickness of the wiring 52 is smaller than the thickness of the electronic component 51, for example, 50 μm or less. The width of the wiring 52 is, for example, 50 μm or more and 10 mm or less.

[Wiring structure]
Subsequently, the cross-sectional structure of the wiring 52 will be described in detail with reference to FIG. FIG. 3 is an enlarged cross-sectional view showing an example of the wiring 52 of the wiring board 10 shown in FIG. 1 and its peripheral components.

As shown in FIGS. 1 and 2, the entire wiring 52 or most of the wiring 52 is arranged so as not to overlap with the stress adjusting mechanism 30 provided with the first reinforcing member 31 and the second reinforcing member 32. Therefore, the stress generated in the substrate 20 due to the expansion and contraction of the substrate 20 is transmitted to the support substrate 40 and the wiring 52 on the support substrate 40. For example, when the tensile stress is removed from the stretched substrate 20 to relax the substrate 20, a compressive stress is generated in the substrate 20, and the compressive stress is transmitted to the support substrate 40 and the wiring 52 on the support substrate 40. As a result, as shown in FIG. 3, a bellows-shaped portion 57 is formed in a portion of the wiring 52 that does not overlap with the stress adjusting mechanism 30.

The bellows-shaped portion 57 includes peaks and valleys in the normal direction of the first surface 21 of the substrate 20. In FIG. 3, reference numeral 53 represents a mountain portion appearing on the front surface of the wiring 52, and reference numeral 54 represents a mountain portion appearing on the back surface of the wiring 52. Further, reference numeral 55 represents a valley portion appearing on the front surface of the wiring 52, and reference numeral 56 represents a valley portion appearing on the back surface of the wiring 52. The front surface is a surface of the wiring 52 located on the side farther from the substrate 20, and the back surface is a surface of the wiring 52 located on the side closer to the substrate 20.

The mountain portions 53, 54 and the valley portions 55, 56 repeatedly appear along the in-plane direction of the first surface 21 of the substrate 20. The period F in which the peaks 53 and 54 and the valleys 55 and 56 repeatedly appear is, for example, 10 μm or more and 100 mm or less.

In FIG. 3, reference numeral S1 represents the amplitude of the bellows-shaped portion 57 on the surface of the wiring 52. The amplitude S1 is, for example, 1 μm or more, more preferably 10 μm or more. By setting the amplitude S1 to 10 μm or more, the wiring 52 is easily deformed following the expansion of the substrate 20. Further, the amplitude S1 may be, for example, 500 μm or less.

The amplitude S1 measures, for example, the distance in the normal direction of the first surface 21 between the adjacent peaks 53 and the valleys 55 over a certain range in the length direction of the wiring 52, and averages them. It is calculated by finding it. The "constant range in the length direction of the wiring 52" is, for example, 10 mm. As the measuring instrument for measuring the distance between the adjacent peaks 53 and the valleys 55, a non-contact measuring instrument using a laser microscope or the like may be used, or a contact measuring instrument may be used. .. Further, the distance between the adjacent mountain portion 53 and the valley portion 55 may be measured based on an image such as a cross-sectional photograph.

In FIG. 3, reference numeral S2 represents the amplitude of the bellows-shaped portion 57 on the back surface of the wiring 52. The amplitude S2 is, for example, 1 μm or more, more preferably 10 μm or more, like the amplitude S1. Further, the amplitude S2 may be, for example, 500 μm or less.

As shown in FIG. 3, a bellows-shaped portion similar to the wiring 52 may be formed on the support substrate 40, the adhesive layer 60, and the first surface 21 of the substrate 20. In FIG. 3, reference numeral S3 represents the amplitude of the bellows-shaped portion on the first surface 21 of the substrate 20. The amplitude S3 is, for example, 1 μm or more, more preferably 10 μm or more. Further, the amplitude S3 may be, for example, 500 μm or less.

FIG. 4 is an enlarged cross-sectional view showing another example of the wiring 52 of the wiring board 10 shown in FIG. 1 and its peripheral components. As shown in FIG. 5, the bellows-shaped portion may not be formed on the first surface 21 of the substrate 20.

The advantage that the bellows-shaped portion 57 shown in FIGS. 3 and 4 is formed in the wiring 52 will be described. As described above, the substrate 20 has an elastic modulus of 10 MPa or less. Therefore, when a tensile stress is applied to the wiring board 10, the board 20 can be stretched by elastic deformation. Here, if the wiring 52 is similarly stretched by elastic deformation, the total length of the wiring 52 increases and the cross-sectional area of the wiring 52 decreases, so that the resistance value of the wiring 52 increases. Further, it is also conceivable that the wiring 52 may be damaged such as cracks due to the elastic deformation of the wiring 52.

On the other hand, in the present embodiment, the wiring 52 has a bellows-shaped portion 57. Therefore, when the substrate 20 is stretched, the wiring 52 can follow the stretching of the substrate 20 by deforming the bellows-shaped portion 57 so as to reduce the undulations, that is, by eliminating the bellows shape. Therefore, it is possible to suppress an increase in the total length of the wiring 52 and a decrease in the cross-sectional area of the wiring 52 with the extension of the substrate 20. As a result, it is possible to suppress an increase in the resistance value of the wiring 52 due to the expansion of the wiring board 10. Further, it is possible to prevent the wiring 52 from being damaged such as a crack.

By the way, as shown in FIGS. 3 and 4, a stress adjusting mechanism 30 including a first reinforcing member 31 and a second reinforcing member 32 is provided in a portion of the substrate 20 that overlaps with the electronic component 51. As described above, the first reinforcing member 31 and the second reinforcing member 32 have a higher elastic modulus than the substrate 20. Therefore, even after the tensile stress is removed from the stretched substrate 20 to relax the substrate 20, the stretched state is at least partially in the portion of the substrate 20 that overlaps with the first reinforcing member 31 and the second reinforcing member 32. Is maintained at. As a result, as shown in FIGS. 3 and 4, the thickness T1 of the portion of the substrate 20 that overlaps the first reinforcing member 31 and the second reinforcing member 32 is the first reinforcing member 31 or the second reinforcing member of the substrate 20. It is smaller than the thickness T2 of the portion that does not overlap with 32. For example, the thickness T1 is 50% or more and 95% or less of the thickness T2. When the bellows shape appears on the first surface 21 of the substrate 20 as shown in FIG. 3, the thickness T2 can be calculated as an average value of the thicknesses of the substrate 20 within the range of the period F.

(Manufacturing method of wiring board)
Hereinafter, a method of manufacturing the wiring board 10 will be described with reference to FIGS. 5A to 5E.

First, the elastic substrate 20 is prepared. Subsequently, as shown in FIG. 5A, an elongation step of applying tensile stress T to the substrate 20 to extend the substrate 20 is carried out. The elongation rate of the substrate 20 is, for example, 10% or more and 200% or less. The stretching step may be carried out in a state where the substrate 20 is heated, or may be carried out at room temperature. When the substrate 20 is heated, the temperature of the substrate 20 is, for example, 50 ° C. or higher and 100 ° C. or lower.

Subsequently, a stress adjusting mechanism 30 is provided on the substrate 20 in a state of being stretched by the tensile stress T. Here, as shown in FIG. 5B, the first reinforcing member 31 is provided on the first surface 21 of the substrate 20, and the second reinforcing member 32 is provided on the second surface 22. The first reinforcing member 31 and the second reinforcing member 32 are provided so as to overlap each other when viewed along the normal direction of the first surface 21. The first reinforcing member 31 and the second reinforcing member 32 may overlap over the entire area or may partially overlap.

Further, as shown in FIG. 5 (c), the support substrate 40 is prepared. In the present embodiment, as shown in FIG. 5C, the electronic component 51 and the wiring 52 are provided on the first surface 41 of the support substrate 40 in the state before being joined to the substrate 20. As a method of providing the wiring 52, for example, a method of printing a conductive paste containing a base material and conductive particles on the first surface 41 of the support substrate 40 can be adopted.

Subsequently, as shown in FIG. 5D, a joining step of joining the second surface 42 of the support substrate 40 provided with the electronic component 51 and the wiring 52 to the elongated substrate 20 from the first surface 21 side. To carry out. The joining step is carried out so that the electronic component 51 mounted on the support substrate 40 overlaps the first reinforcing member 31 and the second reinforcing member 32 on the substrate 20. At the time of the joining step, the adhesive layer 60 may be provided between the substrate 20 and the support substrate 40.

After that, a shrinkage step of removing the tensile stress T from the substrate 20 is carried out. As a result, as shown by the arrow C in FIG. 5 (e), the substrate 20 contracts, and the support substrate 40 and the wiring 52 joined to the substrate 20 are also deformed. The third elastic modulus of the support substrate 40 is larger than the first elastic modulus of the substrate 20. Therefore, the deformation of the support substrate 40 and the wiring 52 can be caused as the generation of the bellows-shaped portion.

Further, in the present embodiment, the first reinforcing member 31 and the second reinforcing member 32 are provided on the stretched substrate 20, and then the support substrate 40 is joined to the stretched substrate 20. Therefore, as compared with the case where the first reinforcing member 31 and the second reinforcing member 32 are provided on the substrate 20 in the state before being stretched, the first reinforcing member 31 and the second reinforcing member 31 and the second reinforcing member 31 are located in the substrate 20 where they overlap with the electronic component 51. It is easy to arrange the reinforcing member 32 with high accuracy. As a result, it is possible to prevent the electronic component 51 from being displaced with respect to the first reinforcing member 31 and the second reinforcing member 32 during the joining process. Such an effect is remarkably exhibited when a plurality of electronic components 51 are mounted on the support substrate 40, and therefore it is difficult to align the support substrate 40 and the substrate 20.

Further, in the present embodiment, the substrate 20 is provided with the first reinforcing member 31 and the second reinforcing member 32. Therefore, after the tensile stress is removed from the stretched substrate 20, it is possible to prevent the portions of the substrate 20 that overlap with the first reinforcing member 31 and the second reinforcing member 32 from relaxing. Therefore, the stress generated by the relaxation of the substrate 20 is difficult to be transmitted to the portion of the support substrate 40 that overlaps with the first reinforcing member 31 and the second reinforcing member 32. Therefore, it is possible to prevent the electronic component 51 on the support substrate 40 from being deformed or damaged due to stress. Further, it is possible to prevent the electrical connection portion between the electronic component 51 and the wiring 52 from being damaged.

As described above, according to the present embodiment, by providing the first reinforcing member 31 and the second reinforcing member 32 on the substrate 20, it is easy to align the support substrate 40 and the substrate 20, the electronic components 51 and the electrons. The reliability of the electrical connection between the component 51 and the wiring 52 can be improved.

An example of the effect on the resistance value of the wiring 52 obtained by the bellows-shaped portion 57 of the wiring 52 will be described. Here, the resistance value of the wiring 52 in the first state in which the tensile stress along the in-plane direction of the first surface 21 of the substrate 20 is not applied to the substrate 20 is referred to as a first resistance value. Further, the resistance value of the wiring 52 in the second state in which tensile stress is applied to the substrate 20 to extend the substrate 20 by 30% in the in-plane direction of the first surface 21 as compared with the first state is referred to as a second resistance value. .. According to the present embodiment, by forming the bellows-shaped portion 57 in the wiring 52, the ratio of the absolute value of the difference between the first resistance value and the second resistance value to the first resistance value is set to 20% or less. It can be more preferably 10% or less, still more preferably 5% or less.

Applications of the wiring board 10 include healthcare products, sports products, amusement products, vibration actuator devices, and the like. For example, a product to be attached to a part of the body such as a human arm is configured by using the wiring board 10 according to the present embodiment. Since the wiring board 10 can be stretched, for example, by attaching the wiring board 10 to the body in an stretched state, the wiring board 10 can be brought into close contact with a part of the body. Therefore, a good wearing feeling can be realized. Further, since it is possible to suppress the decrease in the resistance value of the wiring 52 when the wiring board 10 is stretched, it is possible to realize good electrical characteristics of the wiring board 10.

It is possible to make various changes to the above-described embodiment. Hereinafter, modification examples will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding portions in the above-described embodiment will be used for the portions that can be configured in the same manner as in the above-described embodiment. Duplicate explanations will be omitted. Further, when it is clear that the action and effect obtained in the above-described embodiment can be obtained in the modified example, the description thereof may be omitted.

(First modification)
In the above-described embodiment, the substrate 20 is provided with the first reinforcing member 31 and the second reinforcing member 32 so that the stretched state of the portion of the substrate 20 that overlaps with the electronic component 51 is maintained, thereby forming the support substrate 40. An example of suppressing the transmission of stress to the electronic component 51 is shown. In this modification, the example of suppressing the stress from being transmitted to the electronic component 51 on the support substrate 40 by relaxing the stress generated in the portion of the substrate 20 that overlaps with the electronic component 51 due to stretching. explain.

FIG. 6 is a cross-sectional view showing a wiring board 10 according to this modification. FIG. 7 is a bottom view showing a case where the wiring board 10 according to this modification is viewed from the second surface 22 side of the board 20. The cross-sectional view shown in FIG. 6 is a view when the wiring board 10 of FIG. 7 is cut along the line BB.

As shown in FIGS. 6 and 7, the stress adjusting mechanism 30 is formed on the second surface 22 of the substrate 20 so as to overlap the electronic component 51 when viewed along the normal direction of the first surface 21. A slit 33 is provided. As shown in FIG. 7, for example, the plurality of slits 33 are arranged along the direction in which the wiring 52 that causes the bellows-shaped portion 57 extends.

FIG. 8 is an enlarged cross-sectional view showing an example of the wiring 52 of the wiring board 10 according to the present modification and the components around the wiring 52. Also in this modification, the bellows-shaped portion 57 is formed in the portion of the wiring 52 that does not overlap with the stress adjusting mechanism 30, as in the case of the above-described embodiment. Therefore, it is possible to prevent the total length of the wiring 52 from increasing and the cross-sectional area of the wiring 52 from decreasing due to the deformation of the substrate 20.

In FIG. 8, reference numeral T3 represents the depth of the slit 33. The depth T3 of the slit 33 is the dimension of the slit 33 in the normal direction of the first surface 21, that is, the thickness direction of the substrate 20. The depth T3 of the slit 33 is at least 10% or more, and may be 30% or more, of the thickness T2 of the portion of the substrate 20 where the slit 33 is not provided. Further, the depth T3 of the slit 33 may be 90% or less of the thickness T2.

9 (a) to 9 (d) are diagrams for explaining the manufacturing method of the wiring board 10 according to the present modification.

First, as shown in FIG. 9A, the substrate 20 is prepared. Subsequently, as shown in FIG. 9B, an elongation step of applying a tensile stress T to the substrate 20 to extend the substrate 20 is carried out. Subsequently, as shown in FIG. 9C, a joining step of joining the second surface 42 of the support substrate 40 provided with the electronic component 51 and the wiring 52 to the elongated substrate 20 from the first surface 21 side. To carry out.

Subsequently, as shown in FIG. 9D, a slit forming step of forming a plurality of slits 33 on the second surface 22 of the portion of the stretched substrate 20 that overlaps with the electronic component 51 on the support substrate 40 is carried out. .. For example, the blade is inserted into the substrate 20 from the second surface 22 side along the thickness direction of the substrate 20. As a result, the stress generated in the portion of the substrate 20 that overlaps with the electronic component 51 on the support substrate 40 can be relieved.

After that, a shrinkage step of removing the tensile stress T from the substrate 20 is carried out. As a result, as shown by the arrow C in FIG. 9E, the substrate 20 contracts, and the support substrate 40 and the wiring 52 joined to the substrate 20 are also deformed. The third elastic modulus of the support substrate 40 is larger than the first elastic modulus of the substrate 20. Therefore, the deformation of the support substrate 40 and the wiring 52 can be caused as the generation of the bellows-shaped portion.

Further, in this modification, by forming a plurality of slits 33 in the substrate 20 as described above, it is possible to relieve the stress generated in the portion of the substrate 20 that overlaps with the electronic component 51 on the support substrate 40. can. Therefore, it is possible to prevent the electronic component 51 on the support substrate 40 from being deformed or damaged due to the stress generated in the substrate 20. Further, it is possible to prevent the electrical connection portion between the electronic component 51 and the wiring 52 from being damaged.

Further, in this modification, since a plurality of slits 33 are formed in the stretched substrate 20, the electronic components in the substrate 20 are compared with the case where the slits 33 are formed in the substrate 20 in the stretched state. It is easy to form the slit 33 accurately at the place where it overlaps with 51. This makes it possible to prevent the electronic component 51 from being displaced with respect to the slit 33. Such an effect is remarkably exhibited when a plurality of electronic components 51 are mounted on the support substrate 40, and therefore it is difficult to align the support substrate 40 and the substrate 20.

(Modification example of wiring board)
In the above-described embodiment and each modification, an example is shown in which the wiring board 10 includes an electronic component 51 mounted on the first surface 21 side of the support board 40. However, the present invention is not limited to this, and the wiring board 10 may not include the electronic component 51. For example, the support substrate 40 in which the electronic component 51 is not mounted may be bonded to the substrate 20. Further, the wiring board 10 may be shipped in a state where the electronic component 51 is not mounted.

Although some modifications to the above-described embodiments have been described, it is naturally possible to apply a plurality of modifications in combination as appropriate.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the description of the following Examples as long as the gist of the present invention is not exceeded.

(Example 1)
As the wiring board 10, a stress having a first reinforcing member 31 located on the first surface 21 of the substrate 20 and a second reinforcing member 32 located on the second surface 22 of the substrate 20, as shown in FIG. The one provided with the adjustment mechanism 30 was manufactured. Hereinafter, a method for manufacturing the wiring board 10 will be described.

≪Preparation of substrate and stress adjustment mechanism≫
A urethane sheet having a thickness of 80 μm, which functions as the substrate 20, was prepared. Further, as the stress adjusting mechanism 30, a laminated body having a copper foil having a square shape with a side of 5 mm and a thickness of 12 μm and an adhesive sheet laminated on the copper foil was prepared. As the adhesive sheet, 8146 manufactured by 3M Co., Ltd. was used. Subsequently, the stress adjusting mechanism 30 made of a laminated body was attached to the first surface 21 and the second surface 22 of the substrate 20 in a state where the substrate 20 made of a urethane sheet was stretched 1.5 times around one axis. At this time, the positions of the stress adjusting mechanism 30 on the first surface 21 side, that is, the first reinforcing member 31, and the stress adjusting mechanism 30 on the second surface 22 side, that is, the second reinforcing member 32 were adjusted so as to overlap each other.

≪Preparation of support board≫
A polyethylene naphthalate (PEN) film having a thickness of 1 μm, which functions as a support substrate 40, was prepared. Subsequently, a conductive paste containing a solvent, a binder resin and conductive particles was patterned on the first surface 41 of the support substrate 40 by screen printing. Diethylene glycol monoethyl ether acetate was used as the solvent. Urethane was used as the binder resin. Silver particles were used as the conductive particles. After patterning, annealing was performed in an oven at 80 ° C. for 30 minutes to volatilize the solvent to form the wiring 52. The wiring 52 has a thickness of 20 μm, a line width of 100 μm, and is configured to be an electrode pair with an interval of 500 μm.

Next, an LED chip having a size of 1.0 × 0.5 mm was mounted between the electrode pairs using a conductive adhesive. As the conductive adhesive, CL-3160 manufactured by Kaken Tech Co., Ltd. was used.

Next, the support substrate 40 provided with the wiring 52 and the LED chip and the substrate 20 provided with the stress adjusting mechanism 30 and stretched 1.5 times are used by 3M's adhesive sheet 8146. I pasted them together. At this time, the substrate 20 and the support substrate 40 were aligned so that the central portion of the square copper foil having a side of 5 mm on one side of the stress adjusting mechanism 30 overlapped with the LED chip.

Then, the extension of the substrate 20 was released. As a result, a bellows-shaped portion was formed on the surface of the wiring 52 in a region other than the region overlapping the stress adjusting mechanism 30, and the wiring board 10 shrank. At this time, the conductive connection of the LED chip was maintained, and the LED chip continued to light.

(Example 2)
As the wiring board 10, a wiring board 10 having a stress adjusting mechanism 30 having a plurality of slits 33 formed on the second surface 22 of the board 20 as shown in FIG. 6 was manufactured. Hereinafter, a method for manufacturing the wiring board 10 will be described.

First, a urethane sheet having a thickness of 80 μm, which functions as the substrate 20, was prepared. Further, in the same manner as in the case of the first embodiment, the support substrate 40 provided with the wiring 52 and the LED chip was prepared. Subsequently, the support substrate 40 and the substrate 20 were bonded to each other using an adhesive sheet 8146 manufactured by 3M Co., Ltd. in a state where the substrate 20 made of a urethane sheet was stretched 1.5 times around one axis.

Subsequently, a plurality of slits 33 were formed on the surface of the substrate 20 opposite to the support substrate 40, that is, the second surface 22, using a cutting plotter device. As the cutting plotter, FC2250 manufactured by GRAPHTEC was used. The pattern of the slits 33 is a grid pattern in which the five slits 33 are orthogonal to each other. The width of the slits 33 was 5 mm, and the distance between the slits 33 was 1 mm. Further, the slit 33 is formed so that the central portion of the region where the plurality of grid-shaped slits 33 are present and the LED chip overlap each other.

Then, the extension of the substrate 20 was released. As a result, a bellows-shaped portion was formed on the surface of the wiring 52 in a region other than the region overlapping the stress adjusting mechanism 30 composed of the grid-shaped slits 33 of the board, and the wiring board 10 contracted. At this time, the conductive connection of the LED chip was maintained, and the LED chip continued to light.

(Comparative Example 2)
The wiring board 10 was produced in the same manner as in the case of the first embodiment except that the stress adjusting mechanism 30 was not provided. In this case, when the wiring board 10 contracts after the extension of the substrate 20 is released, the conduction connection of the LED chip is disconnected due to the contraction, and the LED is not lit.

10 Wiring board 20 Board 21 First surface 22 Second surface 30 Stress adjustment mechanism 31 First reinforcing member 32 Second reinforcing member 33 Slit 40 Support board 41 First surface 42 Second surface 51 Electronic components 52 Wiring 53, 54 Yamabe 55, 56 Valley part 57 Bellows shape part 58 Sealing part 60 Adhesive layer

Claims (12)

A substrate that has elasticity and includes a first surface and a second surface located on the opposite side of the first surface.
A support substrate bonded to the substrate from the first surface side of the substrate and having an elastic modulus higher than that of the substrate.
The wiring provided on the support board so as to be connected to the electrodes of the electronic components mounted on the support board, and the peaks and valleys in the normal direction of the first surface of the board are the above-mentioned of the board. Wiring with a bellows-shaped portion that repeatedly appears along the in-plane direction of the first surface,
It is provided with a stress adjusting mechanism provided in a part of the substrate so as to suppress the stress generated in the substrate due to expansion and contraction from being transmitted to the support substrate.
The support substrate is located between the substrate and the wiring in the thickness direction.
The stress adjusting mechanism is located on the first surface of the substrate so as to overlap the electronic components mounted on the support substrate when viewed along the normal direction of the first surface, and the elastic coefficient of the substrate. Positioned on the second surface of the substrate so as to overlap the first reinforcing member having a higher elastic coefficient and the electronic component mounted on the support substrate when viewed along the normal direction of the first surface. A wiring board comprising a second reinforcing member having an elastic coefficient higher than that of the substrate. A substrate that has elasticity and includes a first surface and a second surface located on the opposite side of the first surface.
A support substrate bonded to the substrate from the first surface side of the substrate and having an elastic modulus higher than that of the substrate.
The wiring provided on the support board so as to be connected to the electrodes of the electronic components mounted on the support board, and the peaks and valleys in the normal direction of the first surface of the board are the above-mentioned of the board. Wiring with a bellows-shaped portion that repeatedly appears along the in-plane direction of the first surface,
It is provided with a stress adjusting mechanism provided in a part of the substrate so as to suppress the stress generated in the substrate due to expansion and contraction from being transmitted to the support substrate.
The stress adjusting mechanism is located on the first surface of the substrate so as to overlap the electronic components mounted on the support substrate when viewed along the normal direction of the first surface, and the elastic coefficient of the substrate. Positioned on the second surface of the substrate so as to overlap the first reinforcing member having a higher elastic coefficient and the electronic component mounted on the support substrate when viewed along the normal direction of the first surface. A wiring board comprising a second reinforcing member having an elastic coefficient higher than that of the substrate. The thickness of the portion of the substrate that overlaps with the first reinforcing member and the second reinforcing member when viewed along the normal direction of the first surface is the normal direction of the first surface of the substrate. The wiring board according to claim 1 or 2 , which is smaller than the thickness of the first reinforcing member or the portion that does not overlap with the second reinforcing member when viewed along the line. The wiring board according to any one of claims 1 to 3 , wherein the first reinforcing member and the second reinforcing member include a metal layer. A substrate that has elasticity and includes a first surface and a second surface located on the opposite side of the first surface.
A support substrate bonded to the substrate from the first surface side of the substrate and having an elastic modulus higher than that of the substrate.
The wiring provided on the support board so as to be connected to the electrodes of the electronic components mounted on the support board, and the peaks and valleys in the normal direction of the first surface of the board are the above-mentioned of the board. Wiring with a bellows-shaped portion that repeatedly appears along the in-plane direction of the first surface,
It is provided with a stress adjusting mechanism provided in a part of the substrate so as to suppress the stress generated in the substrate due to expansion and contraction from being transmitted to the support substrate.
The support substrate is located between the substrate and the wiring in the thickness direction.
The stress adjusting mechanism includes a plurality of slits formed on the second surface of the substrate so as to overlap electronic components mounted on the support substrate when viewed along the normal direction of the first surface . Wiring board. A substrate that has elasticity and includes a first surface and a second surface located on the opposite side of the first surface.
A support substrate bonded to the substrate from the first surface side of the substrate and having an elastic modulus higher than that of the substrate.
The wiring provided on the support board so as to be connected to the electrodes of the electronic components mounted on the support board, and the peaks and valleys in the normal direction of the first surface of the board are the above-mentioned of the board. Wiring with a bellows-shaped portion that repeatedly appears along the in-plane direction of the first surface,
It is provided with a stress adjusting mechanism provided in a part of the substrate so as to suppress the stress generated in the substrate due to expansion and contraction from being transmitted to the support substrate.
The stress adjusting mechanism includes a plurality of slits formed on the second surface of the substrate so as to overlap electronic components mounted on the support substrate when viewed along the normal direction of the first surface. Wiring board. The wiring board according to any one of claims 1 to 6 , wherein the bellows-shaped portion of the wiring has an amplitude of 1 μm or more. The wiring board according to any one of claims 1 to 7 , wherein the board contains silicone rubber. The wiring board according to any one of claims 1 to 8 , wherein the wiring includes a plurality of conductive particles. The wiring board according to any one of claims 1 to 9 , further comprising an electronic component located on the support board and having an electrode electrically connected to the wiring. It is a method of manufacturing a wiring board.
A stretching step of stretching the substrate by applying tensile stress to the first surface and the second surface located on the opposite side of the first surface and having elasticity.
A first reinforcing member having an elastic modulus higher than the elastic modulus of the substrate is provided on the first surface of the substrate, and a second reinforcing member having an elastic modulus higher than the elastic modulus of the substrate is provided on the first surface of the substrate. The process to be provided on two sides and
A support substrate having an elastic modulus higher than that of the substrate and provided with wiring connected to electrodes of electronic components mounted on the support substrate is stretched onto the substrate. The joining process of joining from the first surface side and
A shrinkage step of removing the tensile stress from the substrate is provided.
The joining step is carried out so that the electronic components mounted on the support substrate overlap with the first reinforcing member and the second reinforcing member when viewed along the normal direction of the first surface.
After the tensile stress is removed from the substrate, the portion of the wiring that does not overlap with the first reinforcing member and the second reinforcing member when viewed along the normal direction of the first surface is the first. A method for manufacturing a wiring board, which has a bellows-shaped portion in which peaks and valleys in the normal direction of one surface repeatedly appear along the in-plane direction of the first surface. It is a method of manufacturing a wiring board.
A stretching step of stretching the substrate by applying tensile stress to the first surface and the second surface located on the opposite side of the first surface and having elasticity.
A support substrate having an elastic modulus higher than that of the substrate and provided with wiring connected to electrodes of electronic components mounted on the support substrate is stretched onto the substrate. The joining process of joining from the first surface side and
A shrinkage step of removing the tensile stress from the substrate is provided.
The second surface of the substrate, which is carried out between the joining step and the shrinking step and overlaps with an electronic component mounted on the support substrate when viewed along the normal direction of the first surface of the substrate. Further equipped with a slit forming process for forming a plurality of slits in the
After the tensile stress is removed from the substrate, the portion of the wiring that does not overlap with the slit when viewed along the normal direction of the first surface is a mountain portion in the normal direction of the first surface. A method for manufacturing a wiring board, which has a bellows-shaped portion in which valley portions repeatedly appear along the in-plane direction of the first surface.

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