JP7406913B2 - Board with wiring and its manufacturing method - Google Patents

Description

The present invention relates to a substrate with wiring, and particularly to a substrate having wiring formed by sintering conductive particles.

A technique is known in which a paste-like composition in which conductive particles are dispersed in a solvent is applied to a base material, and the solvent is evaporated by heating, and the conductive particles are sintered to form wiring, etc. on the base material. It is being By using fine particles of several nanometers to several tens of micrometers as the conductive particles, the conductive particles can be sintered at a relatively low temperature, so it is also possible to use a resin base material.

Patent Document 1 discloses that during production, in order to prevent agglomeration of conductive particles, the surface of the conductive particles is covered with an organic substance, and the organic substance is further replaced with a polymer dispersant having acidic and basic functional groups. ing. Patent Document 1 describes that this makes it possible to obtain a paste-like composition that can be sintered at low temperatures and has sufficient adhesion to the base material.

Furthermore, Patent Document 2 discloses that conductive particles with an average primary particle diameter of 1 to 150 nm are used in order to reduce the volumetric shrinkage caused by heating to suppress cracks in the sintered body and improve corrosion resistance. , and conductive particles of 1 to 10 μm in a predetermined ratio are dispersed in a reducing organic solvent. Since the micro-sized conductive particles restrict the free movement of the nano-sized conductive particles, the volumetric shrinkage rate during sintering is reduced, and the generation of coarse voids and cracks is suppressed. It is also stated that by using nano-sized conductive particles coated with an organic dispersant, an organic compound layer remains on the surface of the sintered body, improving corrosion resistance.

Patent Document 3 discloses a structure in which a conductive film is mounted on a polyimide substrate, and the components of the conductive film and the polyimide substrate penetrate into each other across an interface. This increases the contact area between the conductive film and the polyimide substrate and improves the adhesion to the polyimide substrate. Further, as the silver powder of the conductive paste that forms the conductive film, silver powder having a coating agent made of rosin, fatty acid, or amines adhered to the surface is used. It is disclosed that this allows sintering to proceed at a low temperature of 250 to 300° C., thereby increasing the adhesion to the polyimide substrate.

Japanese Patent Application Publication No. 2014-55332 Japanese Patent Application Publication No. 2015-11899 Patent No. 6263146

Boards with wiring are used in applications where the heat of the light source is conducted, such as in lighting equipment, or in applications where stress may be applied to the board during use, such as credit cards. Strong adhesion is required to prevent the wiring from peeling off from the board even when the wiring is applied.

An object of the present invention is to provide a wiring-equipped board in which wiring is firmly attached to the board.

In order to achieve the above object, the present invention provides a wiring-equipped substrate having a substrate and a wiring layer disposed on the substrate and bonded to the substrate. In the cross section of the bonding area between the substrate and the wiring layer, the substrate and the wiring layer each have an uneven shape, and the protrusions of the substrate fit into the recesses of the wiring layer, and the protrusions of the wiring layer fit into the protrusions of the substrate. The interface is in close contact with each other. The convex portion of the substrate and the convex portion of the wiring layer have three-dimensional shapes that are asymmetrical in each direction centered on an axis perpendicular to the main plane of the substrate and the wiring layer.

According to the present invention, since the convex portions having an asymmetric three-dimensional shape in each direction with respect to an axis perpendicular to the main plane of the substrate and the wiring layer are fitted into the concave portions of the wiring layer and the substrate, the wiring It is possible to provide a board with wiring in which the layer is firmly attached to the board.

FIG. 1 is a cross-sectional view of a wiring-equipped board according to an embodiment. FIG. 3 is an explanatory diagram showing the shape of the interface of the wiring-equipped substrate according to the embodiment. (a) and (b) Diagrams explaining the manufacturing process of the wiring-equipped substrate of the embodiment. SEM photograph of the cross section of the wiring board of Example 1. SEM photograph of the cross section of the wiring board of Example 3.

An embodiment of the present invention will be described below.

FIG. 1 is a cross-sectional view of the wiring-equipped board of this embodiment. FIG. 2 is an enlarged schematic diagram illustrating the uneven structure of the bonding region between the substrate and the wiring layer of the substrate with wiring.

As shown in FIGS. 1 and 2, the wiring board of this embodiment includes a board 1 and a wiring layer 2 disposed on the board 1 and bonded to the board. In the cross section of the bonding region 3 between the substrate 1 and the wiring layer 2, the substrate 1 and the wiring layer 2 each have an uneven shape. The convex portions 11 (11-1 to 11-6) of the substrate 1 fit into the concave portions 22 (22-1 to 22-6) of the wiring layer 2, and the convex portions 21 (21-1 to 21-6) of the wiring layer 2 fit into the concave portions 22 (22-1 to 22-6) of the wiring layer 2. 6) is fitted into the recesses 12 (12-1 to 12-6) of the substrate 1, so that the interface 31 between the two is in close contact (however, the substrate 1 and the wiring layer 2 are separated from each other in some parts). ). At this time, the convex portion 11 of the substrate 1 and the convex portion 21 of the wiring layer 2 are asymmetrical in each direction about an axis 32 that passes through the center of each base and is perpendicular to the main plane of the substrate 1 and the wiring layer 2. It has a three-dimensional shape (see, for example, the convex portion 11-2 in FIG. 2).

In this way, in the bonding region 3 between the substrate 1 and the wiring layer 2, the convex portions 11 and 21 having a complicated three-dimensional shape fit into the concave portions 22 and 12 having a corresponding shape, so that the substrate 1 and wiring layer 2 have a structure in which they are three-dimensionally intertwined in the bonding region 3. This increases the contact area between the board 1 and the wiring layer 2 and increases the durability against stress in various directions applied to the wiring layer 2, so that a board with wiring in which the wiring layer 2 is firmly attached to the board 1 can be obtained. It will be done.

At this time, at least some of the protrusions 11 of the substrate 1 and the protrusions 21 of the wiring layer 2 (11-2, 11-4, 11-6) have at least one constriction 41 between the base and the tip. This is desirable. The "constriction" in this embodiment is a part of a convex part where the thickness is thinner than that of the front and back. By providing the convex portions 11 and 21 with the constrictions 41, the shape of the interface 31 between the substrate 1 and the wiring layer 2 becomes more complicated, so that the wiring layer 2 can be more firmly attached to the substrate 1. In addition, it is more desirable that the number of constrictions is plural for one convex portion.

Furthermore, some of the protrusions 11 of the substrate 1 and the protrusions 21 of the wiring layer 2 (11-1, 11-3, 11-5, 21-6) may have a branched shape. "Branching" in this embodiment refers to a shape in which a convex part is further formed with a convex part (the convex part is divided into two or more parts). This is because branching creates a more complex shape and improves the degree of adhesion. Note that it is more desirable that the number of branches is plural for one convex portion. Further, it is preferable that the convex portion 11 of the substrate 1 has a branch portion whose tip end extends toward the main body of the substrate 1 because the convex portion 11 of the substrate 1 has a particularly complicated shape. Similarly, it is preferable that the convex portion 21 of the wiring layer 2 has a branch portion whose tip end extends toward the main body of the wiring layer 2 because the convex portion 21 of the wiring layer 2 has a particularly complicated shape. The main body portion in this case refers to the central region that is not the interface or surface portion of the substrate 1 or the wiring layer 2.

Further, at least some of the protrusions 11 of the substrate 1 and the protrusions 21 of the wiring layer 2 (11-2, 11-6, 21-2, 21-4, 21-5) are hook-shaped. is desirable. In the present embodiment, "hook shape" refers to a shape in which the central axis of the convex portion is not a straight line. By fitting the hook-shaped convex part into the correspondingly shaped concave part, even when a force is applied to peel off the wiring layer 2, the hook-shaped convex part is not easily caught in the concave part and peeled off, improving adhesion. do.

Further, it is desirable that the cross section of the bonding region between the substrate 1 and the wiring layer 2 includes at least one region of the island-shaped wiring layer 2 surrounded by the substrate 1. Similarly, it is desirable that the cross section of the bonding region between the substrate 1 and the wiring layer 2 include at least one island-shaped region of the substrate 1 surrounded by the wiring layer 2.

At least a portion of the wiring layer 2 is made of a material obtained by sintering conductive particles. By sintering the conductive particles under predetermined conditions, it is possible to form a three-dimensional convex portion that is asymmetrical in each direction.

It is desirable that an organic substance 51 be sandwiched in a part of the interface 31 between the uneven shape of the substrate 1 and the uneven shape of the wiring layer 2. By sandwiching the organic material between the interfaces 31, the substrate 1 and the wiring layer 2 can be firmly bonded together due to the adhesive effect of the organic material. It is more preferable that the organic material 51 is polyvinylpyrrolidone or a fired product of polyvinylpyrrolidone. Polyvinylpyrrolidone or its fired product can particularly improve the adhesion between the wiring layer 2 and the substrate 1 after the wiring layer 2 is sintered.

It is desirable that the bonding region 3 includes holes 61 . Since the bonding region 3 includes the holes 61, when a stress that bends the wiring layer 2 or the substrate 1 is applied, the holes 61 deform and the wiring layer 2 or the substrate 1 becomes flexible. This makes it difficult for the wiring layer 2 to peel off even when deformation such as bending occurs. Note that the range of the bonding region 3 herein refers to the maximum range of the unevenness of the interface 31 in the film thickness direction. That is, the maximum value of the distance from the base to the tip of the protrusions 11 and 21 in the film thickness direction is the thickness of the bonding region 3.

Note that the holes 61 may be included not only on the wiring layer 2 side but also within the convex portions 11 of the substrate 1.

The length from the base to the tip of the convex portions 11 and 21 of the substrate 1 and the wiring layer 2 is desirably 1/4 or less of the substrate thickness. The diameter of the convex portion 21 of the wiring layer 2 is desirably 1/4 or less of the wiring thickness at its thickest point. The diameter of the convex portion 11 of the substrate 1 is desirably 1/4 or less of the thickness of the substrate at its widest point.

The size of the pores included in the bonding region 3 is preferably 1/4 or less of the wiring thickness.

The diameter of the conductive particles constituting the wiring layer 2 before sintering is preferably 1 μm or less.

The substrate 1 can be made of resin. Further, the substrate 1 may be flexible or transparent. When a transparent substrate 1 is used, when sintering the conductive particles of the wiring layer 2 by photosintering, the wiring layer 2 can be irradiated with light through the substrate 1. This provides the advantage that the uneven interface 31 described above can be easily formed.

<<Method for manufacturing board with wiring>>
A method for manufacturing a wiring-equipped board according to this embodiment will be described. First, a sintering composition (referred to as conductive ink) that becomes the wiring layer 2 by sintering is prepared. The conductive ink includes conductive particles, an organic dispersant that coats the conductive particles, and a solvent. The composition of the conductive ink is preferably in the range of 20 wt% to 95 wt% of conductive particles, 5 wt% to 70 wt% of solvent, and 0.01 wt% to 10 wt% of organic dispersant. For example, a conductive ink in which silver particles as conductive particles are dispersed in a solvent at a ratio of 80 wt % or more is prepared.

Conductive ink is applied to the substrate 1 to form a conductive ink film 20 (FIG. 3(a)), and the conductive particles contained in the conductive ink are sintered by heating the film 20 to form a wiring layer. 2 (Fig. 3(b)). Thereby, a board with wiring in which the wiring layer 2 is mounted on the board 1 can be manufactured.

Note that as a heating method, in addition to heating using an oven or the like, a method of irradiating electromagnetic waves such as light as shown in FIG. 3(b) can be used. When the substrate 1 has a property of transmitting electromagnetic waves such as light, as shown in FIG. By sintering, it is possible to manufacture a wiring-equipped substrate having a bonding region 3 having a structure in which the asymmetrical three-dimensional convex portions 11 and 21 of this embodiment fit into each other.

<Conductive particles>
As the material constituting the conductive particles of the conductive ink, for example, one or more of conductive metals and conductive metal oxides such as Au, Ag, Cu, Pd, ITO, Ni, Pt, and Fe are used. be able to.

The maximum value of the particle size distribution of the conductive particles of the conductive ink is less than 250 nm, and preferably 200 nm or less. However, some particles may be included that exceed the maximum value of the particle size distribution within an error range. The minimum value of the particle size distribution of the conductive particles is desirably less than 50 nm, more desirably 10 nm or less. As a result, the proportion of voids (including the voids 61) in the cross section of the wiring layer 2 is small, and the size of each void is also reduced, so the thermal resistivity can be reduced and the sintered product Heat dissipation can be improved.

<Solvent>
As the solvent for the conductive ink, glycols such as ethylene glycol, triethylene glycol, and polyethylene glycol, organic solvents such as amines, alcohols, ethers, aromatics, ketones, and nitriles, and water can be used. The boiling point of the solvent of the conductive ink is desirably less than 260°C.

<Organic dispersant>
Examples of organic dispersants for coating conductive particles include polymers such as polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA), amines, hydroxyl groups, carboxyl groups, alkoxy groups, carbonyl groups, ester groups, mercapto groups, etc. A compound containing a functional group, etc. can be used. In particular, PVP or PVA can be suitably used.

<Method for manufacturing conductive particles>
The conductive particles are desirably manufactured so as to be coated with an organic dispersant. For example, it is produced by preparing an organic dispersant solution in which an organic dispersant is dissolved in a solvent, and dropping a metal ion solution containing metal ions into the solution. Thereby, the conductive particles coated with the organic dispersant can be deposited.

<Substrate>
Materials for the substrate 1 include polyimide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), liquid crystal polymer, glass epoxy, paper phenol, ceramic, glass-containing silicone glass, glass, etc. A metal coated with an insulating layer or the like can be used.

Examples 1 and 2 of the present invention will be described below.

<<<Examples 1 and 2>>>
<Synthesis of silver nanoparticles>
First, silver nanoparticles were synthesized as conductive particles used in the conductive inks of Examples 1 and 2. The surface of these silver nanoparticles is coated with polyvinylpyrrolidone (PVP), which is an organic dispersant, to prevent agglomeration.

Silver nanoparticles were synthesized by a polyol method. First, PVP (molecular weight 20,000) and 100 g of diethylene glycol as a solvent were stirred to dissolve PVP in the solvent, and this PVP solution was heated. The amount of PVP was 6 g in Example 1 and 8 g in Example 2.

On the other hand, 6 g of silver nitrate and 20 g of diethylene glycol were stirred to prepare a solution in which silver nitrate was dissolved in diethylene glycol. This solution was added dropwise to the heated PVP solution.

After dropping, the mixture was slowly cooled to room temperature, and PVP-coated silver nanoparticles were synthesized. By centrifuging the synthesis solution with ethanol, spherical silver nanoparticles coated with PVP were obtained.

<Manufacture of sintering composition>
Silver nanoparticles coated with PVP were added dropwise to polyethylene glycol (average molecular weight 200) as a solvent at a concentration of 90 wt % and mixed. Stirring treatment was performed as necessary. In this way, conductive inks of Examples 1 and 2 were manufactured.

In addition, the composition of the conductive ink of Examples 1 and 2 is as long as the silver particles are in the range of 20 wt% to 95 wt%, the solvent is in the range of 5 wt% to 70 wt%, and the organic dispersant is in the range of 0.01 wt% to 10 wt%. It is also possible to change.

<Manufacture of circuit boards with wiring>
The conductive inks of Examples 1 and 2 are applied to the surface of a light-transmitting polyimide substrate 1 to a thickness of 10 μm and a width of 200 μm to form a film 20, and this film 20 is exposed to laser light from the back side of the substrate 1. Electromagnetic waves such as light or flash light were irradiated through the substrate. As a result, the silver nanoparticles of the sintering composition are irradiated with light, the film 20 and the substrate 1 around it are intensively heated, the silver nanoparticles in the film 20 are sintered, and a sintered body is formed. A wiring layer 2 was formed. At this time, a part of the substrate irradiated with light melts and solidifies again after entering a part of the wiring layer 2, so that the convex portion 11 of the substrate 1 having an asymmetric three-dimensional shape as shown in FIG. A convex portion 21 of the wiring layer 2 is formed, and the substrate 1 and the wiring layer 2 are firmly attached to each other at the interface. In addition, a part of the organic dispersant (PVP) enters the interface between the wiring layer 2 and the substrate 1 and functions as an adhesive, thereby making the bond between the wiring layer 2 and the substrate 1 even stronger.

As described above, a wiring-equipped substrate formed by sintering the sintering compositions (conductive ink) of Examples 1 and 2 was manufactured.

Note that the parts of the substrate other than the film of the sintering composition (conductive ink) and its surroundings remained unmelted.

<<<Comparative Examples 1 and 2>>>
As Comparative Examples 1 and 2, we prepared two types of conductive inks made by other companies, in which the silver particles dispersed in an organic solvent had a spherical shape and did not contain polyvinylpyrrolidone. A board with wiring was manufactured according to the procedure.

＜＜Evaluation＞＞
<Cross-sectional SEM photo>
The wiring-equipped substrates of Examples 1 and 2 and Comparative Examples 1 and 2 were cut and photographed by SEM. A SEM photograph of a cross section of the wiring board of Example 1 is shown in FIG.

As shown in FIG. 4, the protrusions 11 of the substrate 1 fit into the recesses 22 of the wiring layer 2, and the protrusions 21 of the wiring layer 2 fit into the recesses 12 of the substrate 1, so that their interfaces are in close contact with each other. was. Further, the convex portion 11 of the substrate 1 and the convex portion 21 of the wiring layer 2 had an asymmetrical shape with respect to an axis 32 passing through the center of each base and perpendicular to the main plane of the substrate 1 and the wiring layer 2.

It was also confirmed from FIG. 4 that some of the convex portions 11 of the substrate 1 and the convex portions 21 of the wiring layer 2 had constrictions 41 between the base and the tip. Furthermore, it was also confirmed from FIG. 4 that some of the convex parts were branched and some were hook-shaped.

Furthermore, it was confirmed from the SEM photograph of FIG. 4 that the bonding region 3 where the convex portions fit into each other contained voids 61.

Further, the interface of the wiring board of Example 2 was also the same as that of Example 1 above.

Furthermore, when the interface between the substrate 1 and the wiring layer 2 was observed at high magnification (100,000 times or more), it was confirmed that organic substances were present at the interface. Since the solvent is considered to have evaporated during sintering, it is assumed that the organic substance present at the interface is polyvinylpyrrolidone or a fired product of polyvinylpyrrolidone.

On the other hand, the shape of the interface between the substrate 1 and the wiring layer 2 of the wiring-equipped substrates of Comparative Examples 1 and 2 resulted in poor adhesion as the substrate and wiring peeled off during sample processing for cross-sectional observation. Therefore, it was assumed that there was a gap at the interface between the board and the wiring.

<Evaluation of adhesion>
Mending tape (Scotch (registered trademark) mending tape manufactured by 3M Company) was pressed onto the wiring layer 2 of the wiring board of Examples 1 and 2 and Comparative Examples 1 and 2 by pressing with a finger, and then mending was performed. Holding the end of the mending tape with your fingers, lift it at an angle of 120 degrees or more to the board 1 and peel it off, and visually observe whether the wiring layer 2 was attached to the peeled mending tape. .

A peel test was similarly performed using cellophane tape (Cellotape (registered trademark) manufactured by Nichiban Co., Ltd.) instead of the mending tape.

Table 1 shows cases in which the wiring layer 2 was not attached to the tape as ○, and cases in which it was attached as ×.

<Bending resistance>
The bending resistance test was conducted by fixing both ends of the wiring board with a jig and bending the center part of the board to R10 or less to check the adhesion between the board and the wiring. Table 1 shows cases in which no peeling occurred in the wiring as ○, and cases in which peeling occurred as ×.

表１により、実施例１、２の配線付基板は、配線層２の基板１に対する密着性に優れ、メンディングテープ試験およびセロハンテープ試験の両方で剥離を生じなかった。これに対し、比較例１は、セロハンテープ試験で剥離を生じ、比較例２は、メンディングテープ試験およびセロハンテープ試験の両方で剥離を生じた。 <Thermal shock resistance>
One cycle consisted of holding the printed circuit boards of Examples 1 and 2 and Comparative Examples 1 and 2 at -40°C for 15 minutes, then holding them at 120°C for 15 minutes, and then cooling them to -40°C, and after repeating this for 1000 cycles. , We observed using a microscope whether there were any cracks in the wiring. Those with no cracks are marked as ○, and those with cracks are marked as ×, as shown in Table 1.

According to Table 1, the wiring-equipped substrates of Examples 1 and 2 had excellent adhesion of the wiring layer 2 to the substrate 1, and no peeling occurred in both the mending tape test and the cellophane tape test. On the other hand, in Comparative Example 1, peeling occurred in the cellophane tape test, and in Comparative Example 2, peeling occurred in both the mending tape test and the cellophane tape test.

Furthermore, the wiring-equipped substrates of Examples 1 and 2 were excellent in bending resistance and thermal shock resistance, whereas the wiring-equipped substrates of Comparative Examples 1 and 2 suffered from peeling of the wiring and cracks.

<<<Example 3>>>
By changing the manufacturing conditions of the wiring board, the bonding surface between the board and the wiring layer can be made to have a more complex and strong structure. Below, regarding the manufacturing conditions of the wiring board of Example 3, only the differences from Examples 1 and 2 will be shown. Items not described below are the same as the manufacturing conditions described in Examples 1 and 2.

<Synthesis of silver nanoparticles>
Silver nanoparticles were synthesized under conditions partially different from those in Examples 1 and 2. PVP (molecular weight 40,000) and 80 g of diethylene glycol as a solvent were stirred to dissolve PVP in the solvent, and this PVP solution was heated. The amount of PVP was 2g.
<Manufacture of sintering composition>
Silver nanoparticles coated with PVP were added dropwise to polyethylene glycol (average molecular weight 200) as a solvent to give a concentration of 80 wt %, and mixed.

＜＜Evaluation＞＞
The wiring board of Example 3 was cut and photographed using SEM. FIG. 5 shows a SEM photograph of a cross section of the wiring board of Example 3.

Similarly to Examples 1 and 2, in Example 3, the protrusions 11 of the substrate 1 fit into the recesses of the wiring layer, and the protrusions 21 of the wiring layer fit into the recesses of the substrate 1, so that both The interface was in close contact. Further, the convex portion 11 of the substrate 1 and the convex portion 21 of the wiring layer 2 had an asymmetrical shape with respect to an axis 32 passing through the center of each base and perpendicular to the main plane of the substrate 1 and the wiring layer 2.

Similar to Examples 1 and 2, constricted and branched shapes were confirmed in Example 3 as well, but what is noteworthy is that the shape was more complex. As shown by A1, A2, and A3 in FIG. 5, a plurality of constrictions are formed in the convex portion 21. Further, as shown by B1, B2, and B3, the convex portion 21 has a plurality of branched shapes. Furthermore, as shown by C1 and C2, the tip of the convex portion of the branched wiring layer is directed toward the main portion of the wiring layer 2. Furthermore, as shown by D, the cross section has an island-shaped wiring layer 2 surrounded by the substrate 1. It is considered that the wiring layer 2 is integrated with the main body of the wiring layer 2 at a portion that does not appear in this cross section. As described above, in Example 3, since the structure around the interface is more complex, stronger adhesion can be achieved.

The wiring-equipped substrates of the embodiments and examples described above can be used for wiring used in printed electronics, touch panels, transparent screens, etc., automotive equipment, lighting equipment, communication equipment, gaming machines, OA equipment, and industrial equipment. It is suitable for applications such as general consumer electronics and credit cards.

DESCRIPTION OF SYMBOLS 1... Substrate, 2... Wiring layer, 3... Bonding area, 11... Convex part of substrate, 12... Recessed part of substrate, 20... Film of conductive ink, 21... Protruding part of wiring layer, 22... Recessed part of wiring layer, 41...constriction, 61...hole

Claims (22)

comprising a substrate and a wiring layer disposed on the substrate and bonded to the substrate,
In a cross section of a bonding region between the substrate and the wiring layer, the substrate and the wiring layer each have an uneven shape, the protrusions of the substrate are in the depressions of the wiring layer, and the protrusions of the wiring layer are in the substrate. They fit into the recesses of each other, and the interfaces are in close contact with each other.
The convex portion of the substrate and the convex portion of the wiring layer have an asymmetric three-dimensional shape in each direction centered on an axis passing through the center of each base and perpendicular to the main plane of the substrate and the wiring layer, At least a portion of the wiring layer is made of a material obtained by sintering conductive particles,
The uneven shape is formed by melting the interface,
A board with wiring, wherein at least a portion of the convex portion of the substrate and the convex portion of the wiring layer has at least one constriction between a base and a tip. 2. The board with wiring according to claim 1 , wherein there are a plurality of said constrictions for one convex portion. comprising a substrate and a wiring layer disposed on the substrate and bonded to the substrate,
In a cross section of a bonding region between the substrate and the wiring layer, the substrate and the wiring layer each have an uneven shape, the protrusions of the substrate are in the depressions of the wiring layer, and the protrusions of the wiring layer are in the substrate. They fit into the recesses of each other, and the interfaces are in close contact with each other.
The convex portion of the substrate and the convex portion of the wiring layer have an asymmetric three-dimensional shape in each direction centered on an axis passing through the center of each base and perpendicular to the main plane of the substrate and the wiring layer, At least a portion of the wiring layer is made of a material obtained by sintering conductive particles,
The uneven shape is formed by melting the interface,
A board with wiring, wherein a part of the convex part of the board and a part of the convex part of the wiring layer have a branched shape. 4. The board with wiring according to claim 3 , wherein there are a plurality of said branches for one said convex portion. 5. The board with wiring according to claim 3 , wherein the convex portion of the substrate or a part of the convex portion of the wiring layer is a branch portion with a tip thereof directed toward the main body of the substrate. A board with wiring, characterized in that it has. comprising a substrate and a wiring layer disposed on the substrate and bonded to the substrate,
In a cross section of a bonding region between the substrate and the wiring layer, the substrate and the wiring layer each have an uneven shape, the protrusions of the substrate are in the depressions of the wiring layer, and the protrusions of the wiring layer are in the substrate. They fit into the recesses of each other, and the interfaces are in close contact with each other.
The convex portion of the substrate and the convex portion of the wiring layer have an asymmetric three-dimensional shape in each direction centered on an axis passing through the center of each base and perpendicular to the main plane of the substrate and the wiring layer, At least a portion of the wiring layer is made of a material obtained by sintering conductive particles,
The uneven shape is formed by melting the interface,
A board with wiring, wherein at least a portion of the protrusions of the substrate and the protrusions of the wiring layer are hook-shaped. comprising a substrate and a wiring layer disposed on the substrate and bonded to the substrate,
In a cross section of a bonding region between the substrate and the wiring layer, the substrate and the wiring layer each have an uneven shape, the protrusions of the substrate are in the depressions of the wiring layer, and the protrusions of the wiring layer are in the substrate. They fit into the recesses of each other, and the interfaces are in close contact with each other.
The convex portion of the substrate and the convex portion of the wiring layer have an asymmetric three-dimensional shape in each direction centered on an axis passing through the center of each base and perpendicular to the main plane of the substrate and the wiring layer, At least a portion of the wiring layer is made of a material obtained by sintering conductive particles,
The uneven shape is formed by melting the interface,
In a cross section of a bonding region between the substrate and the wiring layer, an island-shaped region of the wiring layer surrounded by the substrate, or an island-shaped region of the substrate surrounded by the wiring layer, A board with wiring, characterized in that it includes at least one. 8. The substrate with wiring according to claim 1, wherein an organic substance is sandwiched in a part of the interface between the uneven shape of the substrate and the uneven shape of the wiring layer. Board with wiring. 9. The wiring-equipped substrate according to claim 8 , wherein the organic substance is polyvinylpyrrolidone or a fired product of polyvinylpyrrolidone. 10. The wiring-equipped substrate according to claim 1, wherein the bonding region includes a hole. The wiring board according to any one of claims 1 to 10 , wherein the length from the base to the tip of the convex portion of the board and the wiring layer is 1/4 or less of the thickness of the board. Features a board with wiring. 12. The wiring-equipped board according to claim 1, wherein the diameter of the convex portion of the wiring layer is 1/4 or less of the thickness of the wiring layer at its thickest point. Board with wiring. 13. The wiring-equipped substrate according to claim 1, wherein the diameter of the convex portion of the substrate is 1 μm or less at the thickest point. 11. The wiring-equipped substrate according to claim 10 , wherein the size of the pores included in the bonding region is 1 nm or less. 15. The wiring-equipped substrate according to claim 1, wherein the conductive particles have a diameter of 100 nm or less. 16. The board with wiring according to claim 1, wherein the board is made of resin. 17. The board with wiring according to claim 1, wherein the board is flexible. a step of applying a solution in which conductive particles are dispersed onto a substrate to form a film with a desired shape;
a step of heating the film to sinter the conductive particles dispersed in the solution to form a wiring layer; and inserting the substrate into the wiring layer or a part of the film to form the wiring layer. 18. The method of manufacturing a wiring-equipped substrate according to claim 1, further comprising the step of causing the film and the substrate to fit into each other. 19. The method for manufacturing a wiring-equipped board according to claim 18 ,
The solution in which the conductive particles are dispersed is
A substrate with wiring characterized in that the composition contains conductive particles in a range of 20 wt% to 89.9 wt%, a solvent in a range of 5 wt% to 70 wt%, and an organic dispersant in a range of 0.01 wt% to 10 wt%. Production method. 20. The method for manufacturing a wiring-equipped substrate according to claim 19 , wherein the organic dispersant is polyvinylpyrrolidone. 20. The method of manufacturing a substrate with wiring according to claim 19 , wherein the heating of the film is performed by irradiating the film with light. 22. The method for manufacturing a wiring board according to claim 21 , wherein the substrate is made of a material that transmits the light, and the light is transmitted through the substrate from the back side of the substrate to irradiate the film. A method of manufacturing a wiring-equipped substrate, characterized in that the film is heated by:

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