JP6431361B2 - Electronic component mounting method - Google Patents

Description

  The present invention relates to a method for mounting an electronic component on a substrate end face.

Electronic parts constituting various electronic devices are generally mounted on the surface of a substrate by joining terminal portions provided on the electronic component to a wiring pattern formed on the surface of the substrate.
However, in such a configuration, since the terminal portion and the wiring pattern are soldered, the substrate projects to the outer peripheral side of the electronic component. Patent Document 1 (Japanese Patent Application Laid-Open No. 2008-10658) is known as a related technique having a configuration in which a board projects to the outer peripheral side of an electronic component in order to perform soldering between a terminal portion and a wiring pattern. However, the configuration disclosed in Patent Document 1 hinders downsizing of the electronic device, effective use of the space in the housing of the electronic device, and the like.

  Therefore, an electronic component may be connected or mounted on an end surface orthogonal to the surface at the outer peripheral portion of the surface of the substrate. Here, as a matter of course, the electronic component needs to be firmly mounted on the substrate. As a related technique for firmly mounting an electronic component on an end surface of a substrate, there is known a technique in which a connector is provided on an end surface of a substrate and an electronic component is connected to this connector as disclosed in Japanese Patent Application Laid-Open No. 2013-206842. It has been.

  However, the configuration as disclosed in Patent Document 2 requires a space for providing a connector. Therefore, it cannot be said that the miniaturization of the electronic device and the effective use of the space in the housing are effectively realized.

  An object of the present invention is to provide an electronic component mounting method capable of reliably miniaturizing an electronic device and effectively using a space while firmly bonding the electronic component to a substrate end surface.

  The present invention provides an electronic component side wiring connection portion of an electronic component on an outer peripheral end surface of a substrate laminate having two substrates opposed to each other and a substrate side wiring connection portion provided between the two substrates. Between the electronic component-side wiring connection portion of the electronic component and the anisotropic conductive film and the outer peripheral end surface of the substrate laminate. A step of interposing bonding ink containing particles, and melting the bonding ink to form a bonding pad between the electronic component side wiring connecting portion and the anisotropic conductive film and the substrate side wiring connecting portion. And a step of forming the electronic component mounting method.

  Further, in the present invention, the bonding ink includes a silver nanoink and a copper nanoink. By irradiating the bonding ink with a laser beam, the silver included in the silver nanoink and the copper included in the copper nanoink You may make it eutectic. By irradiating the bonding ink with laser light, the copper contained in the copper nano ink absorbs the laser light and melts. Along with this, the silver contained in the silver nano ink is also melted, eutectic with the melted copper, and connected to the substrate-side wiring connection portion.

  In the present invention, the bonding ink may be melted so that the bonding ink enters between the two substrates and is bonded to the substrate-side wiring connection portion.

  In the present invention, the electronic component may include a film substrate having the electronic component side wiring connection portion and a chip component mounted on the film substrate.

  Furthermore, in the present invention, the electronic component may include an anisotropic conductive film interposed between the electronic component side wiring connection portion and the bonding pad.

  In the present invention, the silver nano ink may include silver (Ag) particles having a particle diameter of 5 to 200 nm.

  In the present invention, the copper nano ink may include copper (Cu) particles having a particle size of 30 to 100 nm.

  In the present invention, the ratio of the silver content and the copper content in the bonding ink may be 50:50 to 90:10 mass%.

  In the present invention, the laser beam may have a wavelength of 400 to 700 nm.

  In the present invention, at least one of the two substrates may be provided with a wiring portion having the substrate-side wiring connection portion on the outer peripheral portion.

  In the present invention, the two substrates may be at least one of a glass substrate, a resin substrate, and a printed substrate.

  In addition, the present invention provides at least one display unit of a liquid crystal display device, an organic light emitting diode display device, or a plasma display panel display device by using the substrate laminate and the electronic component joined to the outer peripheral end face of the substrate laminate. May be formed.

  According to the present invention, the following effects can be obtained.

  That is, according to the present invention, it is possible to reliably reduce the size of the electronic device and effectively use the space while firmly bonding the electronic component to the end surface of the substrate.

It is sectional drawing which shows the structure of a part of display apparatus comprised by applying the mounting method of the electronic component in this embodiment. It is a top view of FIG. It is a left view of FIG. It is the microscope picture which observed the penetration | invasion condition of the ink for joining to the clearance gap between two glass substrates in the cross section along the clearance gap between glass substrates.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment for implementing an electronic component mounting method according to the invention will be described with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing a partial configuration of a display device configured by applying the electronic component mounting method according to the present embodiment. FIG. 2 is a plan view of FIG. FIG. 3 is a left side view of FIG.
As shown in FIGS. 1 to 3, a display device 100 includes a liquid crystal panel (substrate laminate) 110, a light source unit (not shown) that provides light to the liquid crystal panel 110, and light emitted from the light source unit. And a light guide portion (not shown) led to the back surface of 110.

  The liquid crystal panel 110 includes a first substrate 111, a second substrate 112 disposed opposite to the first substrate 111, a liquid crystal layer (not shown) disposed between the first substrate 111 and the second substrate 112, It has.

  At least one of the first substrate 111 and the second substrate 112 (the first substrate 111 in the example of FIG. 1) includes a signal wiring including a data line and a gate line (not shown), a thin film transistor (Thin Film Transistor), and the like. A wiring part 113 is provided. The wiring unit 113 drives the liquid crystal in the liquid crystal layer between the first substrate 111 and the second substrate 112 to form a display image (video) on the liquid crystal panel 110.

In such a liquid crystal panel 110, the electronic component 130 is mounted on the outer peripheral end surface 110s orthogonal to the display surface 110f in the outer peripheral portion of the display surface 110f of the liquid crystal panel 110.
The electronic component 130 includes a film-like wiring board (film-like board) 131 and a chip part 132 such as an LSI (Large Scale Integration) mounted on the surface 131 f of the wiring board 131.

A plurality of electronic components 130 are provided on a plurality of substrate-side wiring connection portions 113 s formed at the end portion of the wiring portion 113 positioned between the first substrate 111 and the second substrate 112 on the outer peripheral end surface 110 s of the liquid crystal panel 110. Are electrically connected through the bonding pad 200.
The bonding pad 200 adheres to the electronic component side wiring connection portion 131s of the wiring board 131 of the electronic component 130, enters between the first substrate 111 and the second substrate 112, and adheres to the substrate side wiring connection portion 113s. Yes. That is, the bonding pad 200 enters between the electronic component bonding portion 200a attached to the electronic component side wiring connection portion 131s of the wiring substrate 131 of the electronic component 130, and the first substrate 111 and the second substrate 112, so that the substrate side wiring And an inter-substrate bonding part 200b attached to the connection part 113s.

  Here, the electronic component side wiring connection portion 131s is formed of copper (Cu), and the bonding pad 200 is formed including silver (Ag) and copper (Cu) as described later. In such a configuration, an anisotropic conductive film (Anisotropic Conductive Film) is provided between the electronic component side wiring connection portion 131 s and the bonding pad 200 in order to improve adhesion of the bonding pad 200 to the electronic component side wiring connection portion 131 s. : ACF) 140 is provided.

  A bezel 150 that forms the outer frame of the display device 100 is provided on the outer periphery of the liquid crystal panel 110. The bezel 150 extends from the one end of the side plate 150a toward the inside of the liquid crystal panel 110 along the outer periphery of the display surface 110f of the liquid crystal panel 110. And at least a front plate portion 150b. The electronic component 130 is accommodated between the side plate portion 150a of the bezel 150 and the outer peripheral end surface 110s of the liquid crystal panel 110.

  In this embodiment, the bonding ink 210 is used for the bonding pad 200. More specifically, the bonding ink 210 has a surface of each particle so as not to aggregate, for example, silver (Ag) particles having a particle diameter of 5 to 200 nm and copper (Cu) particles having a particle diameter of 30 to 100 nm, for example. A special chemical modification is performed and mixed and dispersed in a dispersion medium such as an organic solvent. Here, the content ratio [silver (Ag): copper (Cu)] of silver (Ag) and copper (Cu) is preferably 50:50 to 90:10 (mass%).

Such a bonding pad 200 is formed as follows.
First, the first substrate 111 and the second substrate 112 are stacked and arranged to face each other. As the bonding ink 210 as described above, for example, a silver nanoink containing silver (Ag) particles having a particle diameter of 5 to 200 nm and a copper nanoink containing copper (Cu) particles having a particle diameter of 30 to 100 nm, for example. Are mixed to produce. Then, the generated bonding ink 210 is applied to the electronic component side wiring connection portion 131 s of the electronic component 130 and the outer peripheral end surface 110 s of the liquid crystal panel 110.

Next, the electronic component side wiring connection portion 131 s of the electronic component 130 and the outer peripheral end surface 110 s of the liquid crystal panel 110 are opposed to each other, and laser light is irradiated. The wavelength of the laser beam to be irradiated is preferably 400 to 700 nm, for example.
The bonding ink 210 containing the copper nano ink in addition to the silver nano ink has a lower reflectance than the silver nano ink alone. Therefore, when the applied bonding ink 210 is irradiated with laser light, the bonding ink 210 efficiently absorbs the energy of the laser light and generates heat. Then, silver (Ag) and copper (Cu) contained in the bonding ink 210 are efficiently melted.

The bonding ink 210 that has been melted and liquefied penetrates between the first substrate 111 and the second substrate 112 by capillary action.
When the laser light irradiation is stopped and the temperature of the bonding ink 210 is decreased, the bonding ink 210 is solidified, and the electronic component side wiring connection portion 131s of the electronic component 130 and the substrate side wiring connection portion 113s of the liquid crystal panel 110 side. The bonding pads 200 that are securely attached to each other are formed.

  As described above, the bonding ink 210 containing silver nano-ink and copper nano-ink is interposed between the outer peripheral end face 110s of the liquid crystal panel 110 facing each other and the electronic-component-side wiring connection portion 131s of the electronic component 130. The bonding ink 210 was melted to bond the electronic component side wiring connection portion 131s and the substrate side wiring connection portion 113s via the bonding pad 200. Thereby, the electronic component 130 can be firmly joined in a state along the outer peripheral end face 110 s of the liquid crystal panel 110. As a result, in order to mount the electronic component 130, it is not necessary to project one of the first substrate 111 and the second substrate 112 to the outer peripheral side, and the liquid crystal panel 110 can be reduced in size. Furthermore, since the electronic component 130 can be directly joined to the outer peripheral end surface 110s of the liquid crystal panel 110, the electronic component 130 can be minimized from projecting to the outer peripheral side. As a result, the display device 100 can be reduced in size and the width of the bezel 140 can be reduced.

  In addition, the bonding ink 210 includes a copper nano ink in addition to the silver nano ink, so that the reflectance decreases. By irradiating such bonding ink 210 with laser light, copper (Cu) contained in the copper nano ink absorbs the laser light and melts. Silver (Ag) contained in the silver nano ink is also melted along with it, and can be efficiently co-crystallized with the previously melted copper (Cu). Accordingly, the bonding ink 210 can be efficiently melted to form the bonding pad 200, and the electronic component side wiring connection portion 131s and the board side wiring connection portion 113s can be bonded.

  Further, by efficiently melting the bonding ink 210 containing silver nano ink and copper nano ink, the bonding ink 210 enters between the first substrate 111 and the second substrate 112, and the substrate side wiring connection portion 113s. Can be firmly bonded to each other.

  Furthermore, the electronic component 130 including the wiring substrate 131 having the electronic component-side wiring connection portion 131s and the chip component 132 mounted on the wiring substrate 131 is firmly and reliably mounted by the above-described method. Can do.

  In addition, the electronic component 130 includes the anisotropic conductive film 140 interposed between the electronic component side wiring connection portion 131s and the bonding pad 200, so that the electronic component side wiring connection portion 131s made of copper (Cu) is The adhesion of the bonding pad 200 containing silver (Ag) can be improved.

(Experimental example)
Here, the reflectance of the bonding ink containing silver nano ink and copper nano ink was measured, and the result is shown.
The content of the copper nano ink with respect to the silver nano ink was two types of 0% by mass and 15% by mass.

Each of the bonding inks was irradiated with a laser beam having a wavelength of 532 nm, and the reflectance was measured.
as a result,
The content of copper nano-ink with respect to silver nano-ink is 0% by mass, that is, silver nano-ink alone: reflectance 55%
When the content of copper nano ink is 15% by mass with respect to silver nano ink: reflectance 29%
Met.
Thereby, it was confirmed that the reflectance of the bonding ink is lowered by adding the copper nano ink to the silver nano ink.

Further, the penetration of silver (Ag) between the two glass substrates was confirmed by irradiating the bonding ink containing silver nanoink and copper nanoink with laser light.
As a test body, two glass substrates bonded with a sealing material were prepared. And the ink for joining which made content of copper nano ink 15 mass% with respect to silver nano ink was apply | coated to the outer peripheral end surface of two glass substrates, and the laser beam was irradiated.
FIG. 4 is a photomicrograph of the state in which the bonding ink enters the gap between the two glass substrates, observed in a cross section along the gap between the glass substrates.
As shown in FIG. 4, it was confirmed that silver contained in the bonding ink had entered about 200 μm into the gap between the two glass substrates.

Further, a tape peeling test was performed on the bonding ink adhered to the glass substrate. The tape peeling test is performed by making a grid-like (cross-cut) cut into the surface of the bonding ink to reach the glass substrate as a base material, then pressing the pressure-sensitive adhesive tape, and peeling the pressure-sensitive adhesive tape. As a result, when the peeling state of the bonding ink by peeling of the adhesive tape was confirmed, no peeling of the bonding ink was observed.
Therefore, by irradiating the bonding ink 210 containing silver nano-ink and copper nano-ink with laser light, the bonding ink 210 enters between the first substrate 111 and the second substrate 112, and enters the substrate-side wiring connection portion 113s. It was confirmed that they were securely joined.

The electronic component mounting method of the present invention is not limited to the above-described embodiment described with reference to the drawings.
For example, in the above embodiment, the wiring part 113 having the board-side wiring connection part 113s is formed on the first substrate 111, but the present invention is not limited to this. The wiring part 113 having the board-side wiring connection part 113s on the outer peripheral part may be formed on at least one of the first substrate 111 and the second substrate 112.
Furthermore, the wiring part 113 may be sandwiched between the first substrate 111 and the second substrate 112.

  Furthermore, the first substrate 111 and the second substrate 112 are not limited to glass substrates, and may be at least one of a resin substrate and a printed substrate.

The display device 100 is not limited to a liquid crystal display device, and the present invention can be similarly applied to an organic light emitting diode display device, a plasma display panel display device, and the like.
In addition to this, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate without departing from the gist of the present invention.

100 Display device 110 Liquid crystal panel (substrate laminate)
110f Display surface 110s Outer peripheral end surface 111 First substrate 112 Second substrate 113 Wiring portion 113s Substrate side wiring connection portion 130 Electronic component 131 Wiring substrate (film-like substrate)
131s Electronic component side wiring connection portion 132 Chip component 140 Anisotropic conductive film 200 Bonding pad 210 Bonding ink

Claims (16)

On the outer peripheral end surface of the substrate laminate having two substrates opposed to each other and the substrate-side wiring connection portion provided between the two substrates, a different difference is provided on the electronic component-side wiring connection portion of the electronic component. While facing the isotropic conductive film, silver and copper particles were included between the electronic component side wiring connection portion of the electronic component and between the anisotropic conductive film and the outer peripheral end surface of the substrate laminate. A step of interposing a bonding ink;
Melting the bonding ink to form a bonding pad between the electronic component side wiring connection portion and the anisotropic conductive film and the substrate side wiring connection portion;
Bei to give a,
The electronic component mounting method , wherein the bonding ink is melted by laser light to enter between the two substrates and bonded to the substrate-side wiring connection portion . The bonding ink comprises a silver nano-ink and copper nano-ink, by irradiating the laser beam to the bonding ink, thereby eutectic copper contained in the silver and the copper nano-inks contained in the silver nanoink, The electronic component mounting method according to claim 1. The electronic component mounting method according to claim 2, wherein the silver nano-ink includes silver particles having a particle diameter of 5 to 200 nm. The electronic component mounting method according to claim 2 , wherein the copper nano-ink includes copper particles having a particle diameter of 30 to 100 nm. The electronic component, the electronic component-side film-shaped substrate having a wiring connection portion, and a chip component mounted on the film-like substrate, electronic according to any one of claims 1 4 Component mounting method. The ratio between the content (mass%) of the copper and the content of the silver in ink the junction, 50: 50-90: 1 0, electrons according to any one of claims 1 to 5 Component mounting method. The laser beam is a wavelength 400 to 700 nm, electronic part mounting method according to any one of claims 1 to 6. At least one of the two sheets of the substrate, the wiring part having the board-side wire connecting portion on the outer peripheral portion is formed, mounting method of electronic components according to any one of claims 1 to 7. Two of the substrate, a glass substrate, a resin substrate is at least one printed circuit board, electronic part mounting method according to any one of claims 1 to 8. The said board | substrate laminated body and the said electronic component joined to the outer peripheral end surface of the said board | substrate laminated body form at least 1 type of display part of a liquid crystal display device, an organic light emitting diode display apparatus, and a plasma display panel display apparatus. The mounting method of the electronic component as described in any one of 1 to 9 . A display panel including a first substrate, a second substrate facing the first substrate, and a substrate-side wiring connection portion between the first substrate and the second substrate;
A bonding pad on the display panel side, wherein a first side of the bonding portion is in contact with a side surface and an upper surface of the substrate-side wiring connection portion;
An electronic component including an electronic component side wiring connection portion and disposed on the second side of the joint opposite to the first side;
And an anisotropic conductive film between the bonding pad and the electronic component,
A display device. The display device according to claim 11, wherein the bonding pad contains silver particles and copper particles. The display device according to claim 12, wherein the silver particles have a particle size of 5 to 200 nm. The display device according to claim 12 or 13, wherein the copper particles have a particle size of 30 to 100 nm. The display device according to claim 12, wherein a mass% ratio of the silver particles to the copper particles is 50:50 to 90:10. 16. The length of the bonding pad according to claim 11, wherein a length of the bonding pad is longer than a distance between the first substrate and the second substrate so that the display panel is sealed by the bonding pad. The display device described.