JPH09260820A - Electronic part mounting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic part mounting method enabling the en bloc mounting of electronic parts having different bonding materials on a laser beam-transmitting board. SOLUTION: A laser beam (infrared ray) irradiated on the lower face of a laser beam-transmitting board 3 is convertible to an ultraviolet beam La through a wavelength converting film 5 laid on the lower face of the board. The laser beam (infrared ray) L is used for those electronic parts 2 using solder 7 as a bonding material while the wavelength-converted ultraviolet beam La is used for those electronic parts using an ultraviolet-setting insulation resin 6, thus mounting the parts en bloc on the board 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component mounting method for joining a substrate and an electronic component by changing a phase of a bonding material by a laser beam transmitted through a laser beam transparent substrate.

[0002]

2. Description of the Related Art Electronic components are mounted on a substrate which is transparent to laser light and are roughly classified into a heat-meltable bonding material and a photo-curable bonding material.

The mounting method shown in FIG. 5 (a) uses a bonding material that can be heated and melted. In the figure, 101 is an electronic component.
101a is an electrode formed on the lower surface of the component, 101b is a bump made of solder or the like attached to the electrode 101a, 102 is a laser-transmissive substrate, 102a is an electrode formed on the upper surface of the substrate, and L1 is a laser in the infrared region. Light.

When the electronic component 101 is mounted on the substrate 102, the laser beam L1 in the infrared region is irradiated on the electrode 102a of the substrate 102 with the bumps 101b of the electronic component 101 placed on the lower surface of the substrate 102 at a predetermined position. That is, the lower surface position corresponding to the bump 101b is irradiated. Board 102
The laser beam L1 applied to the lower surface of the substrate passes through the substrate 102 and reaches the electrode 102a.
Is heated by the transmitted laser beam L1, and the heat melts the bump 101b to bond the electrodes to each other.

The mounting method shown in FIG. 5B uses a photo-curable bonding material. In the figure, 101 is an electronic component, 1
01a is an electrode formed on the lower surface of the component, 102 is a laser-transmissive substrate, 102a is an electrode formed on the upper surface of the substrate,
Reference numeral 103 is an ultraviolet curing insulating resin, and L2 is a laser beam in the ultraviolet region.

When the electronic component 101 is mounted on the substrate 102, the laser light L2 in the ultraviolet region is applied to the substrate 102 with the electrode 101a of the electronic component 101 being overlaid on the electrode 102a of the substrate 102 with the insulating resin 103 interposed therebetween. The predetermined position on the lower surface of 102, that is, the lower surface position corresponding to the insulating resin 103 is irradiated. Laser light L2 irradiated on the lower surface of the substrate 102
Passes through the substrate 102 and reaches the insulating resin 103,
As a result, the insulating resin 103 is cured, and the electrodes are bonded to each other due to the contraction stress during curing.

The mounting method shown in FIGS. 5A and 5B is generally selected according to the heat resistance of the electronic component to be mounted, and heat is applied to the electronic component during the bonding process. a)
The mounting method in FIG. 5 is mainly used for mounting high heat resistant parts, and the mounting method in FIG. 5B in which heat is not applied to electronic parts in the joining process is mainly used for mounting low heat resistant parts.

[0008]

The respective mounting methods described above are
Both are common in that the bonding material is phase-changed by the transmitted laser light to bond the substrate and the electronic component, but since the wavelength of the laser light used is basically different depending on the type of bonding material, solder is used as the bonding material. When mounting an electronic component that uses a resin and an electronic component that uses an insulating resin as a bonding material on the same substrate, a light source and an optical system that can irradiate laser beams of different wavelengths are required, and the component is mounted for each bonding material. There is a problem that the above must be carried out separately.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a mounting method of electronic components capable of collectively mounting electronic components having different bonding materials on a substrate that transmits laser light. Especially.

[0010]

In order to achieve the above object, the present invention is directed to irradiating a laser beam on one surface of a substrate which is transparent to a laser beam, and changing the phase of a bonding material by the laser beam transmitted through the substrate. In a method of mounting an electronic component that joins the other surface with an electronic component, a wavelength conversion element capable of converting the wavelength of the irradiation laser light is provided at a predetermined position on the substrate, and a non-wavelength transmitted laser light and a wavelength-converted transmission laser light are transmitted. The main feature is that the other surface of the substrate and the electronic component are joined by using laser light according to the joining material.

In the mounting method according to the present invention, the wavelength of the laser light radiated on one surface of the substrate transparent to laser light can be converted to another wavelength by the wavelength conversion element provided on the substrate.
Even when a different bonding material is used for each mounted component, laser light having a wavelength corresponding to each bonding material can be produced from the irradiation laser light to collectively mount the components.

[0012]

1 and 2 show one embodiment of the present invention, in which 1 is an electronic component such as an IC chip using an ultraviolet curing insulating resin 6 as a bonding material, and 2 is a bonding. An electronic component such as a multilayer chip capacitor using the solder 7 as a material, 3 is a substrate transparent to laser light, 4 is a laser light reflecting film, 5 is a wavelength conversion film, and L is laser light in the infrared region.

The laser light L is infrared light having a wavelength of 1.064 μm, which is emitted from a YAG laser or the like as a light source, and is directly irradiated onto the lower surface of the substrate 3 through an optical system (not shown).

The substrate 3 is made of a material that is transparent to the laser light L, for example, sapphire, zirconia, barium fluoride, calcium fluoride, aluminum nitride, quartz, or another ceramic or glass, or polyimide, acrylic, PET, glass. The substrate 3 is made of a resin such as epoxy, and on the upper surface of the substrate 3, electrodes 3a and 3b corresponding to the lower surface electrode 1a of the electronic component 1 and the opposite end electrodes 2a of the electronic component 2 are formed.

The laser light reflection film 4 is made of a material having reflectivity for the laser light L, such as aluminum or stainless steel, and is formed on the lower surface of the substrate 3. The light reflection film 4 is provided with light passage holes 4a corresponding to the mounting position of the electronic component 1 and the substrate electrode 3b for the electronic component 2.

The wavelength conversion film 5 is made of BBO (β-BaB
_It is composed of a laminated body of a ₂ O ₄ ) film 5a and an LBO (LiB ₃ O ₅ ) film 5b, and is provided on the lower surface of the substrate 3 corresponding to the mounting position of the electronic component 1. The wavelength conversion film 5 converts the laser light L (infrared light having a wavelength of 1.064 μm) with which the wavelength conversion film 5 is irradiated into ultraviolet light La having a quaternary high frequency of 166 nm in the course of passing through the laser light L.

When mounting the electronic components 1 and 2 having different bonding materials on the substrate 3, first, the insulating resin 6 is attached to the mounting position of the electronic component 1 on the substrate 3, and the substrate 3 is mounted.
The solder 7 is attached to the electrode 3b for the electronic component 2 in FIG.

Then, the electrode 1a of the electronic component 1 is superposed on the electrode 3a of the substrate 3 with the insulating resin 6 interposed therebetween, and the electrode 3b is formed.
Laser light (infrared light) L is applied to the entire lower surface of the substrate 3 in a state where the electrode 2a of the electronic component 2 is superposed on the upper surface of the substrate 3 via the solder 7 (see FIG. 2).

Of the laser light L radiated toward the entire lower surface of the substrate 3, the laser light L directed to the laser light reflection film 4 is reflected by the laser light reflection film 4, but the light passage hole below the electrode 3b. The laser light L directed to 4a is directly applied to the substrate 3
Reaches the electrode 3b through which the electrode 3b is heated by the transmitted laser beam L, and the heat melts the solder 7 and the electrode 3b of the substrate 3 and the electrode 2a of the electronic component 2.
And are joined electrically and mechanically.

Further, the laser light L directed to the wavelength conversion film 5 is converted into ultraviolet light La in the process of passing through the wavelength conversion film 5, and after conversion, passes through the substrate 3 and reaches the insulating resin 6.
As a result, the insulating resin 6 is cured and the contraction stress at the time of curing cures the electrode 3a of the substrate 3 and the electrode 1a of the electronic component 1 electrically and mechanically.

As described above, according to the mounting method described above, a part of the laser light (infrared light) L irradiated on the lower surface of the substrate 3 is converted into ultraviolet light by the wavelength conversion element 5 provided on the lower surface of the substrate 3. It can be converted to La and solder 7 can be used as a bonding material.
The laser light (infrared light) L is used as it is for the electronic component 2 using the same, and the irradiation laser light L is used for the electronic component 1 using the ultraviolet curing insulating resin 6 as the bonding material. It can be used after being converted into ultraviolet light La by the method of 5.

Therefore, even when the electronic components 1 and 2 having different bonding materials are mounted on the same substrate 3, the wavelength conversion film 5 can be arranged on the lower surface of the substrate 3 in accordance with the mounting position of the electronic component 1. The electronic components 1 and 2 can be collectively mounted on the substrate 3 using the single laser beam L, and the time and cost required for component mounting can be significantly reduced.

FIG. 3 shows another embodiment of the present invention. In the figure, reference numeral 11 denotes a laser light transmissive substrate, and 11a and 11a.
b is an electrode, 12 is a laser light reflection film, 12a is a light passage hole,
Reference numeral 13 is a wavelength conversion film composed of a BBO film 13a and an LBO film 13b, and since the individual structure is the same as that of the embodiment shown in FIGS. 1 and 2, its description is omitted.

The present embodiment differs from the embodiments shown in FIGS. 1 and 2 in that the laser light reflection film 12 and the wavelength conversion film 13 are formed in the substrate 11. If such a board structure is adopted, electronic components can be mounted on the lower surface as well as the upper surface of the board 11.

FIG. 4 shows still another embodiment of the present invention. In the figure, reference numeral 21 denotes a laser light transmissive substrate, 21a,
Reference numeral 21b is an electrode, 22 is a second substrate transparent to laser light, 2
3 is a laser light reflection film, 23a is a light passage hole, and 24 is BBO.
The wavelength conversion film is composed of the film 24a and the LBO film 24b, and the individual configuration except the second substrate 22 is the same as that of the embodiment shown in FIGS.

The difference between this embodiment and the embodiment shown in FIGS. 1 and 2 is that a second laser-transmissive substrate 22 that can be attached to the component mounting substrate 21 is separately prepared. On the substrate 22 side of the laser light reflection film 23 and the wavelength conversion film 24.
There is a point. By using such a second substrate 22, it is not necessary to provide the laser light reflection film 23 and the wavelength conversion film 24 on the component mounting substrate 21, and the second substrate 22 is repeatedly used to mount a desired component. It can be performed on the substrate 21.

In the above embodiment, solder is used as an example of the heat-meltable joining material, but a conductive material capable of heat-melting by infrared irradiation, heat curing, heat diffusion, welding, etc. is used instead. Alternatively, an ultraviolet curable insulating resin has been exemplified as the photocurable bonding material, but a conductive material or an anisotropic conductive material that can be cured by ultraviolet irradiation may be used instead.

Further, in the above-mentioned embodiment, the laminated body of the BBO film and the LBO film is exemplified as the wavelength conversion film, but other elements may be used instead of this as long as the same wavelength conversion is possible. Good.

[0029]

As described in detail above, according to the present invention,
Even when different bonding materials are used for each mounted component, it is possible to create a laser beam having a wavelength corresponding to each bonding material from the irradiation laser light and perform the component mounting at once. The cost can be reduced significantly.

[Brief description of drawings]

FIG. 1 is a mounting structure diagram according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a mounting method according to an embodiment of the present invention.

FIG. 3 is a sectional view of a substrate according to another embodiment of the present invention.

FIG. 4 is a substrate sectional view according to still another embodiment of the present invention.

FIG. 5 is a diagram showing a conventional mounting method.

[Explanation of symbols]

1, 2 ... Electronic component, 1a, 2a ... Electrode, 3 ... Laser light transmissive substrate, 3a, 3b ... Electrode, 4 ... Laser light reflecting film,
4a ... Light passing hole, 5 ... Wavelength conversion film, 5a ... BB0 film, 5
b ... LBO film, 6 ... UV curable insulating resin, 7 ... Solder,
L ... Laser light (infrared light), La ... Ultraviolet light, 11 ... Laser light transmissive substrate, 11a, 11b ... Electrode, 12 ... Laser light reflection film, 12a ... Light passage hole, 13 ... Wavelength conversion film, 13
a ... BB0 film, 13b ... LBO film, 21 ... Laser light transmissive substrate, 21a, 21b ... Electrode, 22 ... Laser light transmissive second substrate, 23 ... Laser light reflective film, 23a ... Light passage hole, 24 ... Wavelength conversion film, 24a ... BB0 film, 24b ...
LBO film.

Claims (5)

[Claims] 1. A method of mounting an electronic component, wherein one surface of a substrate transparent to laser light is irradiated with laser light, and the bonding material is phase-changed by the laser light transmitted through the substrate to bond the other surface of the substrate to an electronic component. In the above, a wavelength conversion element capable of converting the wavelength of the irradiation laser light is provided at a predetermined position of the substrate, and the non-wavelength-converted transmitted laser light and the wavelength-converted transmitted laser light are used according to the bonding material. A method of mounting an electronic component, comprising: joining a surface and the electronic component. 2. The electronic component mounting method according to claim 1, wherein the wavelength-unconverted laser light is in the infrared region and the wavelength-converted laser light is in the ultraviolet region. 3. The electronic component mounting method according to claim 1, wherein the wavelength conversion element is provided on one surface of the substrate. 4. The method of mounting an electronic component according to claim 1, wherein the wavelength conversion element is provided in the substrate. 5. The method of mounting an electronic component according to claim 1, wherein the wavelength conversion element is provided on a second laser light transmitting substrate which can be attached to the laser light transmitting substrate.