JPH1051129A - Mounting method and mounting structure of circuit components - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable reflowing of solder, curing of conductive resin, etc., by irradiation of laser light or the like, without depending upon the material of a circuit board, and being hindered by a wiring pattern inside the circuit board, or circuit components mounted on the other surface of the circuit board. SOLUTION: A circuit components 4 are mounted on a circuit board 6. Terminal electrodes 5 of the circuit components 4 are mounted on land electrodes 7 of the circuit board 4 via low melting point metal or conductive resin. From the side of the circuit components 4 or from above them, electromagnetic waves are introduced to the low melting point metal or the conductive resin on the land electrodes and irradiation is performed. When the terminal electrodes 5 of the circuit components 4 are fixed to the land electrodes 7b to obtain electric continuity, by the low melting point metal or the conductive resin, a mounting jig is used in which waveguides 2 are formed to introduce electromagnetic waves to the low melting point metal or the conductive resin on the land electrodes 7, from the side of the circuit components 4 or from above them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive resin having a low melting point metal such as solder or a conductor, in which a circuit component is mounted on a circuit board and terminal electrodes of the circuit component are mounted on land electrodes formed on the circuit board. The present invention relates to a mounting method and a mounting structure of a circuit component which is conductively fixed by the method.

[0002]

2. Description of the Related Art Generally, a multilayer capacitor or a multilayer inductor is mounted on a circuit board by solder reflow. In general, semiconductor devices are mounted by wire bonding, but recently, mounting methods such as flip-chip and TAB methods have been used. However, these circuit component mounting methods have problems in that the circuit components are exposed to a high temperature during solder reflow or flip chip bonding, and the circuit components are damaged or characteristics are deteriorated.

In order to avoid such a problem, as disclosed in Japanese Patent Application Laid-Open No. 5-109824, a circuit board having a light-transmitting property is used, and a solder or a solder bump is applied to the solder or the solder bump from the back surface of the circuit board. There has been proposed a method of mounting a circuit component in which a terminal electrode of the circuit component is conductively fixed on a land electrode of a circuit board by irradiating light and locally generating heat to reflow the solder reflow or the solder bump.

[0004]

However, in such a method of mounting circuit parts, only a glass-ceramic substrate having high light-transmitting property with respect to laser light can be used as a circuit board, and the selection of a material for the circuit board is restricted. receive.
Furthermore, in the case where the internal wiring is formed with a circuit board having a multilayer structure, the internal wiring hinders the irradiation of laser light, or a laser light irradiation path is secured.
Some places where internal wiring cannot be partially formed. further,
If circuit components are mounted on both sides of the circuit board by the above-described method, laser light cannot be applied to the circuit components mounted on the other surface because the previously mounted circuit components are in the way. In order to secure the irradiation path of the laser beam, there are places where some circuit components cannot be mounted.

The present invention has been made in view of the above problems of the conventional circuit component mounting method and mounting structure, and regardless of the material of the circuit board, is not limited to the wiring pattern inside the circuit board or mounted on the other surface of the circuit board. The mounted circuit components do not cause any obstacles, and the reflow of the solder and the hardening of the conductive resin can be performed by irradiating a laser beam or the like. To provide.

[0006]

According to the present invention, in order to achieve such an object, a laser beam or the like is irradiated from the surface of the circuit board 6 opposite to the surface on which the circuit components 4, 10 are mounted. Instead, a laser beam or the like is guided to the solder 8 and the solder bump 11 on the land electrodes 7 and 7 of the circuit board 6 from above or beside the circuit components 4 and 10 on the circuit board 6, whereby the solder 8 and The solder bumps 11 were reflowed to connect the terminal electrodes 5 and 5. The same applies to the case where a connection is made by photo-curing a conductive resin instead of the solder 8 or the solder bump 11. Further, in order to carry out this method, for example, a laser beam or the like is guided from the side or above the circuit components 4, 10 toward the solder 8, the solder bump 11, or the conductive resin on the land electrode 7. A mounting jig on which a waveguide is formed is used.

That is, in the method for mounting circuit components according to the present invention, the circuit components 4 and 10 are mounted on the circuit board 6 and the circuit electrodes 6 are placed on the land electrodes 7 of the circuit board 6 via a low melting point metal or a conductive resin. The terminal electrodes 5 of the components 4 and 10 are placed, and electromagnetic waves are guided and radiated to the low melting point metal or the conductive resin on the land electrodes 7 from the side or above the circuit components 4 and 10 to irradiate the circuit components 4 and 10. The terminal electrode 5 is conductively fixed to the land electrode 7 with the low melting point metal or conductive resin.

In this case, a mounting jig having a waveguide 2 for guiding an electromagnetic wave from the side or above the circuit components 4 and 10 toward the low melting point metal or conductive resin on the land electrode 7 is used. I do. Such a mounting jig includes a jig plate 1 having a through hole 3 for accommodating circuit components 4 and 10 mounted on a circuit board 6, and a bottom surface of the jig plate 1 in contact with the circuit board 6. A quartz film is formed and patterned to form an electromagnetic wave waveguide 2. This waveguide 2
In some cases, a filter 12 for attenuating or converting the wavelength of electromagnetic waves guided to the low melting point solder or conductive resin on some of the land electrodes 7 may be provided. As the waveguide for guiding the electromagnetic wave toward the low melting point metal or the conductive resin on the land electrode 7 of the circuit board 6, a mirror 13 or an optical fiber 14 can be used in addition. When the optical fiber 14 is used, it is mounted on the circuit board 6 by the circuit components 4 and 10.
Can also be provided on the component chuck 15 on which is mounted.

The low melting point metal on the land electrode 7 of the circuit board 6 is, for example, a granular solder 8 or a solder bump 11 provided on the lower surface of a circuit component 10 which is a semiconductor component. The conductive resin on the land electrodes 7 of the circuit board 6 is made of a photo-curable conductive resin or a thermosetting conductive resin. Then, irradiating such a low melting point metal or conductive resin,
In general, an infrared laser or an ultraviolet laser is used as an electromagnetic wave for reflowing or photocuring them.

In such a circuit component mounting method, an electromagnetic wave such as a laser beam is irradiated from the surface of the circuit board 6 on which the circuit components 4 and 10 are mounted. The electromagnetic wave can be radiated to a target location without being disturbed by the circuit components 4, 10 and the like previously mounted on the other surface. That is, electromagnetic waves are guided from above or from the sides of the circuit components 4 and 10 on the circuit board 6 to the solder 8 and the solder bumps 11 on the land electrodes 7 and 7 of the circuit board 6 or a photo-curable conductive resin. Accordingly, the terminal electrodes 5, 5 of the circuit components 4, 10 can be conductively fixed to the land electrodes 7, 7 by reflowing the solder 8 and the solder bumps 11 or by photo-curing the conductive resin.

[0011]

Embodiments of the present invention will now be described specifically and in detail with reference to the drawings. FIG. 1 shows an example in which chip-shaped circuit components 4 such as a multilayer ceramic capacitor and a multilayer ceramic inductor are mounted on a circuit board 6. In particular, in FIG. 1, four chip-shaped circuit components 4 are arranged. An example of mounting will be described.

First, as shown in FIG. 1A, a circuit board 6 on which four sets of land electrodes 7 are formed is prepared. The circuit board 6 is formed by forming a circuit pattern including the land electrode 7 on the main surface of an insulating substrate such as alumina and the inside thereof as required. Next, a granular solder 8 is applied on the land electrodes 7 of the circuit board 6. At the same time, by applying a flux 9 to the land electrode 7, the granular solder 8 can be temporarily fixed, which is convenient.

Next, the jig plate 1 is put on the circuit board 6. The jig plate 1 is made of a silicon plate or the like provided with a rectangular through hole 3 corresponding to a position on the circuit board 6 where the circuit component 6 is mounted. For example, a quartz film is formed on the lower surface of the jig plate 1 by a laser film forming method, and the quartz film is patterned by irradiating a laser beam with an excimer laser irradiating apparatus, thereby forming the waveguide 2. Is formed. The waveguide 2 extends from an end surface of the jig plate 1 to a position facing the solder 8 provided on the land electrode 7 when the jig plate 1 is placed at a predetermined position on the circuit board 6. It is.

Next, a chip-shaped circuit component is disposed as a circuit component 4 in the through-hole 3 of the jig plate 1, and terminal electrodes 5, 5 at both ends thereof are connected to the granular material provided on the land electrode 7. On the solder 8. Next, as shown by an arrow in FIG. 1, laser light is incident from a laser entrance of the waveguide 2 on the end face of the jig plate 1 by a YAG laser oscillator (not shown), and the laser light is transmitted to the waveguide 2. Accordingly, the solder 8 on the land electrode 7 is guided and irradiated, and the absorbed heat reflows the solder 8. Thereafter, by stopping the laser beam irradiation, the solder 8 is re-hardened, and the terminal electrodes 5 and 5 of the circuit component 4 are soldered to the land electrodes 7 of the circuit board 6. Thereafter, the mounting of the circuit component 4 on the circuit board 6 is completed by removing the jig plate 1.

FIG. 2 shows an example in which a flip-chip, which is a semiconductor component, is mounted on a circuit board 6 as a circuit component 10 together with a chip-shaped circuit component as the circuit component 4. In FIG. An example in which circuit components 4 which are chip-shaped circuit components are arranged side by side on one side of a certain circuit component 10 will be described. Therefore, here, two sets of land electrodes (not shown) for mounting the circuit components 4 which are two chip-shaped circuit components, and one set of lands for soldering the circuit components 10 which are the flip-chips. The circuit board 6 on which the electrodes 7 are formed is prepared. Although not particularly shown, the solder bumps 11 of the flip-chip circuit component 10 are formed on small terminal electrodes of the circuit component 10.

Next, as in the example of FIG.
The jig plate 1 is put on the jig plate 1, and the jig plate 1
Circuit component 1 placed on the land electrode 7 from the end face of
A filter 12 is arranged in the waveguide 2 at a position facing the solder bump 11 of the No. 0. For example, the filter 12 cuts a part of the waveguide 2 patterned as described above, and then laser-deposits quartz and alumina at the position to form a mixed film of quartz and alumina partially. The mixed film is formed into a waveguide 2 by an excimer laser.
It can be formed by etching on the same trajectory as.
Here, the filter 12 made of a mixed film of quartz and alumina functions as an attenuation filter for the YAG laser.

Next, in the same manner as in the example of FIG. 1, laser light is irradiated from the laser irradiation port of the waveguide 2 on the end face of the jig plate 1 by a YAG laser oscillator. By using the jig plate 1 in which 12 is inserted in the middle of the waveguide 2, for example, only the laser beam irradiated to the solder bump 11 of the circuit component 10 can be attenuated and weakened. Accordingly, even when the solder 8 (not shown) used for connecting the terminal electrodes 5 and 5 of the circuit component 4 is eutectic solder and the solder bump 11 of the circuit component 10 is low-temperature solder, the laser Irradiation with light enables soldering.

On the other hand, as the filter 12, instead of a mixed film of quartz and alumina, quartz and BBO (β-BaB ₂
When the filter 12 composed of a mixed film of O ₄ ) and LBO (LiB ₃ O ₅ ) is formed, a function as a wavelength conversion filter for converting the wavelength of laser light into a short wavelength is obtained. Since such a wavelength conversion filter converts a laser wavelength into an ultraviolet wavelength, it is effective for a photopolymerized resin. By inserting the filter 12 having such a wavelength conversion function in the middle of some of the waveguides 2, the terminal electrodes of some circuit components are connected to the land electrodes with a thermosetting conductive resin, and the other Even when the terminal electrodes of the circuit components of the portion are connected to the land electrodes with a photocurable conductive resin, the curing can be performed at the same time.

In each of the above-described examples, the waveguide 2 is formed on the lower surface of the jig plate 1 and the laser light is irradiated from the side along the upper surface of the circuit board 6, as shown in FIGS. An example is
In each case, laser light is irradiated from above the circuit board 6 on which the circuit components 4 are mounted, and the laser light is guided to the solder 8 to perform soldering. The example shown in FIG.
Is formed at the lower edge of the through hole 3 at an angle of 45 °, and the mirror 13 is formed with this slope as a mirror surface. As shown by an arrow in FIG. 3, a laser beam is directed perpendicularly to the circuit board 6 toward the mirror 13, the direction of the laser beam is changed by 90 ° by the mirror 13,
And reflow it. As a result, the terminal components 5, 5 of the circuit component 4 are soldered to the land electrodes 7.

In the example shown in FIG. 4, a concave portion having a slope of 45.degree. Is formed outside the lower portion of the through hole 3 of the transparent jig plate 2, and the inclined surface on the side of the through hole 3 is a mirror surface. 1
3 is formed. As shown by an arrow in FIG. 4, a laser beam is irradiated perpendicularly to the circuit board 6 from above the jig plate 2 toward the mirror 13, and the direction of the laser beam transmitted through the jig plate 2 is changed as described above. The angle is changed by 90 ° by the mirror 13 and the granular solder 8 is irradiated and reflowed. As a result, the terminal components 5, 5 of the circuit component 4 are soldered to the land electrodes 7.

In the example shown in FIG. 5, an optical fiber 14 is held outside the through hole 3 of the jig plate 2, and a waveguide is formed with its tip facing the solder 8. As shown by an arrow in FIG. 5, a laser beam is made incident on the optical fiber 14 from above the jig plate 2, this is guided to the solder 8 and irradiated, and the solder 8 is reflowed. As a result, the terminal components 5, 5 of the circuit component 4 are soldered to the land electrodes 7.

In the example shown in FIG. 6, an optical fiber 14 is held by a component chuck 15 composed of a vacuum nozzle for mounting a circuit component 4 which is a chip-shaped circuit component on a circuit board 6. When the circuit component 4 is held by the component chuck 15 and the circuit component 4 is mounted on the circuit board 6, the tip of the optical fiber 14 is directed to the solder 8 previously applied on the land electrode 7. Therefore, immediately after the circuit component 4 is mounted on the circuit board 6, the laser light is applied through the optical fiber 14 while the circuit component 4 is held by the component chuck 15.
, The solder 8 reflows. As a result, the terminal components 5 and 5 of the circuit component 4 are connected to the land electrodes 7.
Solder to

On the other hand, the example shown in FIG.
Are temporarily fixed on the circuit board 6, and the end thereof is arranged to face the solder 8. As shown by an arrow in FIG. 7, a laser beam is made incident on the optical fiber 14 from the side of the circuit board 6, and the laser beam is guided and irradiated to the solder 8 to reflow the solder 8. As a result, the terminal components 5, 5 of the circuit component 4 are soldered to the land electrodes 7.

[0024]

As described above, in the method and structure for mounting circuit components according to the present invention, the land electrodes 7, 7 of the circuit substrate 6 are mounted from above or beside the circuit components 4, 10 on the circuit substrate 6. Since the laser light or the like is guided to the solder 8, the solder bump 11, or the conductive resin, regardless of the material of the circuit board 6, the wiring pattern inside the circuit board 6 or the circuit board 6 may be used.
The circuit components mounted on the other surface do not become an obstacle, and the solder 8 and the solder bumps 11 can be reflowed by irradiation of a laser beam or the like, or the conductive resin can be cured.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part and a vertical sectional side view of a main part showing an example of a method for mounting a circuit component according to the present invention.

2A and 2B are a main part plan view and a main part vertical sectional side view showing another example of a method for mounting a circuit component according to the present invention.

FIG. 3 is a vertical sectional side view of a main part showing another example of a method for mounting a circuit component according to the present invention.

FIG. 4 is a vertical sectional side view of a main part showing another example of a method for mounting circuit components according to the present invention.

FIG. 5 is a vertical sectional side view of a main part showing another example of a method for mounting circuit components according to the present invention.

FIG. 6 is a vertical sectional side view of a main part showing another example of a method for mounting circuit components according to the present invention.

FIG. 7 is a vertical sectional side view of a main part showing another example of a method for mounting circuit components according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 jig plate 2 waveguide of jig plate 3 through hole of jig plate 4 circuit component 5 terminal electrode of circuit component 6 circuit board 7 land electrode on circuit board 8 solder 10 circuit component 11 solder bump of circuit component 12 filter 13 Mirror 14 Fiber 15 Parts chuck

Claims (11)

[Claims] 1. A circuit component (4), (10) is mounted on a land electrode (7) formed on a circuit board (6), and a terminal electrode (5) of the circuit component (4), (10) is mounted. ) Is fixed to the land electrode (7) via a low-melting metal or a conductive resin.
(10) is mounted on the circuit board (6), and the terminal electrodes of the circuit components (4) and (10) are placed on the land electrodes (7) of the circuit board (6) via a low melting point metal or a conductive resin. (5) is placed, and electromagnetic waves are guided and radiated to the low melting point metal or conductive resin on the land electrode (7) from the side or above the circuit components (4) and (10) to irradiate the circuit component (4). , (1
A method for mounting a circuit component, wherein the terminal electrode (5) of (0) is conductively fixed to the land electrode (7) with the low melting point metal or the conductive resin. 2. Circuit components (4) and (10) are mounted on land electrodes (7) formed on a circuit board (6), and terminal electrodes (5) of the circuit components (4) and (10) are mounted. ) Is fixed to the land electrode (7) via a low-melting metal or a conductive resin.
(10) is mounted on the circuit board (6), and the terminal electrodes of the circuit components (4) and (10) are placed on the land electrodes (7) of the circuit board (6) via a low melting point metal or a conductive resin. (5) is mounted, and a waveguide on which an electromagnetic wave is guided from the side or above the circuit components (4) and (10) toward the low melting point metal or conductive resin on the land electrode (7) is formed. The jig is used to guide and irradiate the low melting point metal or the conductive resin on the land electrode (7) from the side or above the circuit components (4) and (10) with electromagnetic waves to irradiate the circuit component (4). , (1
A method for mounting a circuit component, wherein the terminal electrode (5) of (0) is conductively fixed to the land electrode (7) with the low melting point metal or the conductive resin. 3. The method according to claim 1, wherein the low melting point metal on the land electrode of the circuit board is granular. 4. The method for mounting a circuit component according to claim 1, wherein the conductive resin on the land electrodes of the circuit board is made of a photocurable conductive resin. 5. The circuit component according to claim 1, wherein the electromagnetic wave applied to the low melting point metal or the conductive resin on the land electrode on the circuit board is a laser beam. Implementation method. 6. A through-hole (3) for housing circuit components (4) and (10) mounted on a circuit board (6).
And a quartz film was formed on the bottom side of the jig plate (1) in contact with the circuit board (6), and this was patterned to form a waveguide (2) for electromagnetic waves. A method for mounting a circuit component according to any one of claims 2 to 5, wherein: 7. A filter (12) for attenuating or converting the wavelength of electromagnetic waves guided to low-melting solder or conductive resin on some of the land electrodes (7) is provided in the middle of the waveguide (2). The method for mounting a circuit component according to claim 6, wherein: 8. A waveguide for guiding an electromagnetic wave toward a low melting point metal or a conductive resin on a land electrode on a circuit board, comprising a mirror. 6. The method for mounting a circuit component according to any one of claims 5 to 5. 9. A waveguide for guiding an electromagnetic wave toward a low melting point metal or conductive resin on a land electrode on a circuit board, comprising an optical fiber. 6. The method for mounting a circuit component according to any one of claims 5 to 5. 10. An optical fiber for guiding an electromagnetic wave toward a low melting point metal or a conductive resin on a land electrode on a circuit board, comprising: a circuit component on the circuit board; The method for mounting a circuit component according to claim 9, wherein the component chuck is provided on a component chuck (15) on which the component (10) is mounted. 11. Circuit components (4) and (10) are mounted on land electrodes (7) formed on a circuit board (6),
In a circuit component mounting structure in which the terminal electrodes (5) of the circuit components (4) and (10) are conductively fixed to the land electrodes (7) via a low melting point metal or a conductive resin, the circuit components (4),
(10) is mounted on the circuit board (6), and the terminal electrodes of the circuit components (4) and (10) are placed on the land electrode (7) of the circuit board (6) via the low melting point metal or the conductive resin. (5) is placed, and electromagnetic waves are guided and radiated to the low melting point metal or conductive resin on the land electrode (7) from the side or above the circuit components (4) and (10) to irradiate the circuit component (4). , (1
A mounting structure for a circuit component, wherein the terminal electrode (5) of (0) is conductively fixed to the land electrode (7) with the low melting point metal or the conductive resin.