JPH09283898A - Mounting method of electronic parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten a long life and reliability by preventing generation of defectives as well as by heightening wiring density of a conductive pattern and mounting density of electronic parts so as to improve production efficiency. SOLUTION: This mounting method is provided with a process of mounting an electronic part A on an electrically insulating substrate 7, a process of jetting a mixed gas F of conductive ultra-fine particles D and a vapor E from a nozzle 12 and a process of forming a conductor pattern 9 on the plate surface of the substrate 7 by relatively shifting the substrate 7 and the jet nozzle 12 as well as joining a part 3a to be connected of the electronic parts A to the conductor pattern 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for mounting electronic components such as a microcomputer and a capacitor, which are brazed to a conductor pattern of a printed wiring board.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view showing an example of a conventional mounting structure for electronic components. In the figure, A is an electronic component,
For example, it is composed of a capacitor having a pair of electrodes 3, and the jointed portions 3a of each of the electrodes 3 are provided so as to be exposed on the component body 1 and are joined to the conductor pattern 4 of the printed wiring board B by the brazing material 5. There is.

In the electronic component A, as shown in FIG. 6 (A), cream-like solder 6 is supplied to the upper surface of the conductor pattern 4 on the printed wiring board B by a printing technique, and then as shown in FIG. 6 (B). Mounted on the above-mentioned cream solder 6,
As shown in (C), it is exposed to a high temperature atmosphere by hot air or infrared rays a. The creamy solder 6 is, for example, Sn.
-Pb eutectic alloy powdered solder and flux containing synthetic resin as a main component are mixed and generated, and exposed to a high-temperature atmosphere, so that the joined portion 3a is transferred to the conductor pattern 4 of the printed wiring board B. It can be brazed.

[0004]

By the way, in recent years, in consideration of the adverse effect of the Pb component contained in the creamy solder 6 on the human body as the brazing material 5 of the electronic component A, the Pb component is not contained. , Sn-Au system,
Various Sn-Sb-based and Sn-Bi-based materials have been studied. The brazing material containing no Pb component is S
In order to obtain the same thermal stability and long-life reliability of the metal structure of the n-Pb eutectic alloy, the melting point tends to be higher than that of the Sn-Pb eutectic alloy.

[0005] Therefore, if the joint 3a is collectively brazed by a reflow method or a flow method using a high melting point brazing material containing no Pb component, the joint 3a is heated to a melting temperature of the high melting point material. The temperature must be increased, and the high temperature heat causes thermal damage to the electronic component A, causing new problems such as the occurrence of defective products and a short life. Also,
Since the joined portion 3a has a heat dissipation effect and lowers the heating temperature of the high melting point material, the heating temperature must be further increased to raise the melting temperature of the high melting point material,
This high temperature heating makes the electronic component A susceptible to thermal damage.

On the other hand, when the creamy solder 6 is supplied by the printing technique to mount the electronic component A, the creamy solder 6 on the upper surface of the conductor pattern 4 is mounted as shown in FIG. 7 (A).
And the mounting displacement of the electronic component A as shown in FIG. That is, the printed wiring board B is formed by covering the electrically insulating substrate 7 with the conductor pattern 4 and printing or mounting the creamy solder 6 and the electronic component A on the already formed conductor pattern 4 with high precision. Since it is extremely difficult to perform
The printing deviation of the creamy solder 6 and the mounting deviation of the electronic component A occur on the upper surface of the above, which is an obstacle to increase the wiring density of the conductor pattern 4 and the mounting density of the electronic component A.

Further, according to the conventional method of mounting the electronic component A on the printed wiring board B, first, the electric insulating board 7 is mounted.
A step of forming the conductor pattern 4 on the printed wiring board B is required, and then the step of printing the creamy solder 6 on the conductor pattern 4 of the printed wiring board B and mounting the electronic component A. However, there is a problem that the process requires a brazing process such as a reflow method or a flow method, and many mounting steps are inefficient.

The present invention has been made in order to solve the above problems, and it prevents defective products from occurring, has a long life and high reliability, increases the wiring density of conductor patterns and the mounting density of electronic parts, and improves production efficiency. It is intended to provide a good electronic component mounting method.

[0009]

In order to achieve the above object, a method for mounting an electronic component according to claim 1 of the present invention comprises:
The step of mounting an electronic component on an electrically insulating substrate, the step of injecting a mixed gas of electrically conductive ultrafine particles and a gas from a nozzle, and the above-mentioned on the plate surface of the substrate while relatively moving the substrate and the injection nozzle. A step of jetting a mixed gas to form a conductor pattern and joining a joined portion of the electronic component to the conductor pattern.

According to a second aspect of the present invention, there is provided a method of mounting an electronic component, wherein an injection nozzle is inclined to a plate surface of an electrically insulating substrate and a mixed gas of conductive ultrafine particles and a gas is injected to a bonded portion of the electronic component. It is characterized by According to a third aspect of the electronic component mounting method of the present invention, the injection time of the mixed gas to the joined portion of the electronic component is made longer than that of the conductor pattern portion.

[0011]

According to the invention of claim 1, the mixed gas of the ultrafine particles and the gas can be jetted from the nozzle to form the conductor pattern on the electrically insulating substrate at room temperature, so that the electronic component is not damaged by heat. It is possible to prevent the formation of a conductor pattern on the substrate and to form a conductor pattern after the electronic component is mounted on the substrate and to join a joined portion of the electronic component to the conductor pattern. The joining of parts can be achieved in the same process, and the production efficiency can be improved.

Further, even when the electronic component is mounted on the electrically insulating substrate in a misaligned manner, a mixed gas is supplied to the misaligned electronic component to position the joined portion of the electronic component on the conductor pattern. Bonding can be performed without deviation, and the mounting density of electronic components can be increased. Further, by increasing the relative moving speed between the substrate and the spray nozzle, for example, the width of the conductor pattern can be reduced to about 30 μm and the pitch of the conductor pattern can be shortened to 50 μm or less. The wiring density can be increased.

According to a second aspect of the present invention, the injection nozzle is inclined to the plate surface of the electrically insulating substrate and the mixed gas of the conductive ultrafine particles and the gas is injected to the bonded portion of the electronic element. It is easy to form a thick joint with the electronic component, and the joint strength can be further increased. Further, as in the invention of claim 3, by making the injection time of the mixed gas to the joined portion of the electronic component longer than that of the conductor pattern portion, the relative distance between the electrically insulating substrate and the injection nozzle is increased. The moving speed can be slowed down, the thickness of the joint with the electronic component can be increased, and the joint strength can be increased to prevent joint failure.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an example of a mounting structure of an electronic component according to the present invention. In the figure, A is an electronic component, which is composed of a capacitor having a pair of electrodes 3, for example. The wiring board C is mounted on the board 7, and the portion to be joined 3a is joined to the conductor pattern 9 formed on the board 7 to form the wiring board C on which the electronic component A is mounted.

FIG. 2 is a schematic view showing an example of an electronic component mounting apparatus. As shown in the figure, a base 11 is installed inside the mounting chamber 10, and injection nozzles 12 are arranged on the upper surface of the base 11 at a predetermined interval. It is connected to the mixed gas transport pipe 14 via the above and is movable in the direction of arrow b. The mixed gas carrier pipe 14 is connected to the conductive ultrafine particles D via a valve 15.
And the gas E are connected to the mixer 16, and the conductive ultrafine particles D are accommodated in the mixer 16 and the introducing pipe 18 for introducing the gas E through the valve 17 is connected. An exhaust pipe 20 is connected to the mounting chamber 10 via a vacuum pump 19 so as to exhaust the internal air to clean the inside of the chamber.

In the above structure, the electrically insulating substrate 7 is mounted on the upper surface of the base 11, and the electronic component A is mounted on the upper surface of the substrate 7 with the adhesive 8 as clearly shown in FIG. 3 (A). Then, as shown in FIG.
The mixed gas F of the gas E and the gas E is jetted from the jet nozzle 12 as a high-speed jet F1. That is, the valve 15,
When gas (carrier gas) E such as N _2, Ar, He or H ₂ is pressure-fed to the mixer 16 through the valve 17 in the open state of 17, conductive ultrafine particles generated inside the mixer 16 A mixed gas F of D and the gas E passes through the carrier pipe 14 and is jetted from the nozzle 12 into a high-speed jet F1 onto the plate surface of the substrate 7.

When the jet nozzle 12 is moved in the direction of arrow b along the plate surface of the substrate 7 in the jet state of the mixed gas F, the conductive ultrafine particles D are deposited on the plate surface of the substrate 7. A thick film conductor pattern 9 made of a material is formed, and the conductor pattern 9 can be joined to the joined portion 3a of the electronic component A. The conductive ultrafine particles D
Is made of one or a plurality of various alloy materials of Sn—Au series, Sn—Sb series and Sn—Bi series which do not contain a single metal such as Au, Ag, Cu or Pb component, and have a particle size of 0. Particles smaller than about 1 μm are adopted.

According to the above-mentioned method of mounting electronic parts, the mixed gas F of the conductive ultrafine particles D and the gas E can be jetted from the nozzle 12 to form the conductor pattern 9 on the electrically insulating substrate 7 at room temperature. The heat damage to the electronic component A can be prevented, the conductor pattern 9 is formed after the electronic component A is mounted on the substrate 7, and the bonded portion 3a of the electronic component A is formed.
Since the conductor pattern 9 can be joined to the substrate 7,
The formation of the conductor pattern 9 and the joining of the electronic component A can be achieved in the same step, and the production efficiency can be improved.

Further, even when the electronic component A is mounted on the electrically insulating substrate 7 with the mount displaced, if the mixed gas F is jetted from the nozzle 12 to the electronic component A with the mount displaced, the target of the electronic component A is covered. The joint portion 3a can be joined to the conductor pattern 7 without displacement, and the electronic component A
The mounting density of can be increased. In that case, if the moving speed of the jet nozzle 12 with respect to the substrate 9 in the direction of the arrow b is slowed down in the region L and the thickness of the joint portion 9a with the electronic component A is formed thick, the joint strength is increased and the joint failure occurs. Can be prevented.

By the way, a joint 9a with the electronic component A is formed.
When forming the thicker wall of the injection nozzle 12, the injection nozzle 12 is inclined to the plate surface of the electrically insulating substrate 7 as shown by the phantom line, and the mixed gas F of the conductive ultrafine particles D and the gas E is supplied to the electronic component A. By injecting into the bonded portion 3a, it is easy to form a thick bonding portion 9a with the electronic component A, and the bonding strength can be further increased. Further, when the moving speed of the spray nozzle with respect to the substrate 7 is increased, the width W of the conductor pattern 9 is arbitrarily narrowed within a range of several μm to about 100 μm, and the pitch P of the conductor pattern 9 is accompanied by this. Can be shortened, and the wiring density of the conductor pattern 9 can be increased.

FIG. 4 is a schematic view showing another example of a method for mounting electronic components. A recess 7a is formed in an electrically insulating substrate 7, the electronic component A is mounted in this recess 7a, and then an injection nozzle 12 is formed. When the mixed gas F of the conductive ultrafine particles D and the gas E is jetted into the gap between the electronic component A and the recess 7a by the jet F1 from the above, the bonded portion 3a of the electronic component A of the conductor pattern 9 is formed. The small and compact wiring board C can be manufactured by joining at the joining portion 9a.

In the above embodiment, the injection nozzle 1
Although the case where 2 is moved in the direction of the arrow b along the plate surface of the substrate 7 has been described, the jet nozzle 12 is held stationary and the base 11 on which the substrate 7 is placed is moved in the direction of the arrow b. You may do it. Further, according to the mounting method of the electronic component described above, the capacitor is described as the electronic component A. However, the electronic component A includes the electronic component A formed of, for example, a resistor, a coil device, a capacitor or a microcomputer as the electrically insulating substrate 7. On the conductor pattern 9
It goes without saying that the present invention can also be applied to the case of mounting together with the formation of.

[0023]

As described above in detail, according to the invention of claim 1, a step of mounting an electronic component on an electrically insulating substrate, a step of injecting a mixed gas of conductive ultrafine particles and a gas from a nozzle, Spraying the mixed gas on the plate surface of the substrate while moving the substrate and the spray nozzle relative to each other to form a conductive pattern and bonding a joined portion of the electronic component to the conductive pattern. As a result, it is possible to provide a method of mounting electronic components, which prevents defective products from occurring, has a long service life and high reliability, increases the wiring density of conductor patterns and the mounting density of electronic components, and has high production efficiency. According to a second aspect of the present invention, the injection nozzle inclines to the plate surface of the electrically insulating substrate and injects a mixed gas of conductive ultrafine particles and a gas into a bonded portion of an electronic element, thereby providing the electronic component. It is easy to form a thick joint, and the joint strength can be further increased. Further, according to the invention of claim 3, the injection time of the mixed gas to the joined portion of the electronic component is made longer than that of the conductor pattern portion, so that the relative movement between the electrically insulating substrate and the injection nozzle is performed. The speed can be slowed down, the thickness of the joint with the electronic component can be increased, and the joint strength can be increased to prevent joint failure.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a mounting structure of an electronic component according to the present invention.

FIG. 2 is a schematic diagram illustrating an example of a mounting device for the electronic component.

FIG. 3 is a side view and a perspective view showing an example of a mounting method of the electronic component.

FIG. 4 is a cross-sectional view showing another example of a method of mounting the electronic component.

FIG. 5 is a cross-sectional view showing an example of a conventional electronic component mounting structure.

FIG. 6 is a cross-sectional view showing an example of a conventional electronic component mounting method.

FIG. 7 is a perspective view for explaining a problem of a conventional electronic component mounting method.

[Explanation of symbols]

 A electronic component D conductive ultrafine particle E gas F mixed gas 1 component body 3a bonded part 7 electrically insulating substrate 9 conductor pattern 12 injection nozzle

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoyuki Nakai 10 Oenron Hachizonocho, Uenkyo-ku, Kyoto City Kyoto Prefecture OMRON Corporation

Claims (3)

[Claims] 1. A step of mounting an electronic component on an electrically insulating substrate, a step of jetting a mixed gas of conductive ultrafine particles and a gas from a nozzle, and a step of relatively moving the substrate and the jet nozzle. A method of mounting an electronic component, comprising the steps of: injecting the mixed gas onto a plate surface to form a conductor pattern and joining a joined portion of the electronic component to the conductor pattern. 2. The injection nozzle is inclined to the plate surface of the electrically insulating substrate to inject a mixed gas of conductive ultrafine particles and a gas onto a bonded portion of an electronic component. Electronic component mounting method. 3. The method of mounting an electronic component according to claim 1, wherein a time period for injecting the mixed gas to the jointed portion of the electronic component is set longer than that of the conductor pattern portion.