JP6295194B2 - Mounting method of electronic components - 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. The anisotropic conductive film provided on the electronic component is opposed to each other, and laser light is absorbed 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 silver nano-ink containing a laser absorber, and irradiating the silver nano-ink containing the laser absorber with a laser beam, whereby the electronic component side wiring connection portion, the anisotropic conductive film, and the substrate And a step of forming a bonding pad between the side wiring connection portion and an electronic component mounting method.

  Further, in the present invention, the silver nano ink containing the laser absorber is irradiated with the laser light, so that the silver nano ink enters between the two substrates and is bonded to the substrate-side wiring connection portion. You may do it. By irradiating the silver nano ink with laser light, the laser absorbing material contained in the silver nano ink generates heat. Along with this, the silver contained in the silver nanoink melts, and the silver nanoink enters between the two substrates by capillary action and is connected 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.

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

  Moreover, this invention may be made to contain 0.5-5 mass% of said laser absorbers with respect to the said silver nanoink.

  Further, 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.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to aim at size reduction of an electronic device and effective utilization of a space reliably, joining an electronic component firmly to a board | substrate end surface.

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 situation of the silver 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) 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, silver nano ink 210 is used for the bonding pad 200. More specifically, the silver nano-ink 210 contains, for example, 63.5 to 83.5% by mass of silver (Ag) particles having a particle diameter of 5 to 200 nm in a dispersion medium such as an organic solvent.

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. Then, a laser absorbent (for example, OIL RED RR manufactured by Orient Chemical Industry Co., Ltd.) is added to the silver nanoink 210 as described above at a ratio of 0.5 to 5% by mass, for example, and mixed. Then, the silver nano ink 210 mixed with the laser absorber 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 silver nanoink 210 containing a laser absorber has a lower reflectance than the silver nanoink 210 alone. Accordingly, when the applied silver nano ink 210 is irradiated with laser light, the laser absorbing material efficiently absorbs the energy of the laser light and generates heat. Then, silver (Ag) contained in the silver nano ink 210 is efficiently melted.

The melted and liquefied silver nano ink 210 permeates between the first substrate 111 and the second substrate 112 by a capillary phenomenon.
When the irradiation of the laser beam is stopped and the temperature of the silver nano ink 210 is lowered, the silver nano 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 on the liquid crystal panel 110 side are set. Bond pads 200 that are securely attached to each other are formed.

  As described above, the silver nano-ink 210 containing a laser absorber is interposed between the outer peripheral end face 110s of the liquid crystal panel 110 and the electronic component-side wiring connection portion 131s of the electronic component 130, and the laser beam is irradiated. As a result, the electronic component side wiring connection portion 131s and the substrate side wiring connection portion 113s were bonded 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, by irradiating the silver nano-ink 210 containing the laser absorber with laser light, the silver nano-ink 210 can enter between the first substrate 111 and the second substrate 112 and can be firmly bonded to the substrate-side wiring connection portion 113s. it can.

  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 when the laser absorbing agent is contained in the silver nano ink 210 is measured, and the result is shown.
The content of the laser absorber with respect to the silver nano ink was set to four types of 0, 1, 2, 5% by mass. As the laser absorber, trade name “OIL RED RR” manufactured by Orient Chemical Industries, Ltd. was used.

Each silver nanoink was irradiated with laser light having a wavelength of 532 nm, a laser output of 5 W, and a processing speed of 10 mm / s, and the reflectance was measured.
as a result,
When the content of the laser absorber is 0% by mass: reflectance 55%
When the content of the laser absorber is 1% by mass: reflectivity 52%
When the laser absorber content is 2% by mass: reflectance 48%
When the content of the laser absorber is 5% by mass: reflectance 37%
Met.
Thereby, it was confirmed that the reflectivity of the silver nano ink decreases as the content of the laser absorbent with respect to the silver nano ink increases.

Further, the penetration of silver (Ag) between two glass substrates by irradiating a silver nano ink containing a laser absorber with laser light was confirmed.
As a test body, two glass substrates bonded with a sealing material were prepared. Then, silver nano ink containing 5% by mass of a laser absorber was applied to the outer peripheral end surfaces of the two glass substrates, and was irradiated with laser light.
FIG. 4 is a photomicrograph of the cross-section along the gap between the glass substrates, showing the state of silver nanoink entering the gap between the two glass substrates.
As shown in FIG. 4, it was confirmed that the silver contained in the silver nano ink entered the gap between the two glass substrates.

Furthermore, a tape peeling test was performed on the silver nano ink adhered to the glass substrate. The tape peeling test is performed by making a grid-like (cross-cut) cut on the surface of the silver nanoink reaching the glass substrate, which is the base material, and then pressing the pressure-sensitive adhesive tape and peeling the pressure-sensitive adhesive tape. As a result, when the peeling state of the silver nano ink by peeling of the adhesive tape was confirmed, the peeling of the silver nano ink was not recognized.
Therefore, by irradiating the silver nano ink 210 containing a laser absorber with laser light, the silver nano ink 210 enters between the first substrate 111 and the second substrate 112 and is reliably bonded to the substrate side wiring connection portion 113s. It was confirmed.

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 132 Chip Component 140 Anisotropic Conductive Film 200 Bonding Pad 210 Silver Nano Ink

Claims (9)

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. A laser absorbent that absorbs laser light between the electronic component side wiring connection portion of the electronic component and the anisotropic conductive film and the outer peripheral end face of the substrate laminate while facing the isotropic conductive film A step of interposing the silver nano-ink included,
A step of forming a bonding pad between the electronic component side wiring connection portion and the anisotropic conductive film and the substrate side wiring connection portion by irradiating the silver nanoink containing the laser absorbent with a laser beam. When,
An electronic component mounting method comprising:   The said silver nanoink containing the said laser absorber is irradiated with the said laser beam, The said silver nanoink penetrates between the two said board | substrates, and is joined to the said board | substrate side wiring connection part. Electronic component mounting method.   The electronic component mounting method according to claim 1, wherein the electronic component includes a film-like substrate having the electronic component-side wiring connection portion, and a chip component mounted on the film-like substrate.   The electronic component mounting method according to any one of claims 1 to 3, wherein the silver nano-ink includes silver particles having a particle size of 5 to 200 nm.   The electronic component mounting method according to claim 1, wherein the laser absorbent is included in an amount of 0.5 to 5 mass% with respect to the silver nanoink.   The electronic component mounting method according to claim 1, wherein the laser beam has a wavelength of 400 to 700 nm.   The electronic component mounting method according to claim 1, wherein a wiring portion having the substrate-side wiring connection portion on an outer peripheral portion is formed on at least one of the two substrates.   The electronic component mounting method according to claim 1, wherein the two substrates are at least one of a glass substrate, a resin substrate, and a printed substrate.   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 8.