JP3365048B2 - Chip component mounting board and chip component mounting method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip part in which an electrode part of the chip part is connected to an electrode land by soldering.
And a mounting method of a chip component .

[0002]

2. Description of the Related Art Chip components such as resistors and capacitors for constituting a predetermined circuit of electronic equipment are mounted on a printed wiring board on which a predetermined wiring pattern is formed and printed wiring by a reflow soldering method or the like. It is electrically connected to the electrode land provided on the plate substrate.

FIG. 5 is a sectional view for explaining a joining state of a conventional printed wiring board and a chip part using the same. As shown in FIG. 5A, the conventional printed wiring board 1 is an insulating substrate 2 mainly made of glass epoxy resin or the like.
And the electrode portion 1 of the chip component 10 formed on the substrate 2.
1 and an electrode land 3 which is joined via a solder 12. Further, a solder resist 4 that does not adhere to the solder 12 is applied to a portion of the substrate 2 except above the electrode lands 3.

In order to mount the chip component 10 using such a printed wiring board 1, first, paste solder 12 is formed on the electrode lands 3 using, for example, a screen printing method.
After a predetermined amount is applied, the predetermined chip component 10 is positioned above the electrode land 3 while being held by a suction collet or the like (not shown).

Next, as shown in FIG. 5B, the chip part 10 is pressed onto the substrate 2 and the electrode portion 1 of the chip part 10 is pressed.
At 1, the paste-like solder 12 is crushed.
As a result, the lower half of the electrode portion 11 of the chip component 10 is embedded in the solder 12, and the solder 12 is mounted on the substrate 2 due to its viscosity. At this time, the solder 12 spreads along the electrode land 3 and the chip component 1
It will be in the state of entering below 0.

Next, as shown in FIG. 5 (c), the printed wiring board 1 on which the chip component 10 is mounted is passed through a reflow furnace or the like (not shown) to melt the solder 12 and form the electrode portion 11 of the chip component 10. The electrode lands 3 on the substrate 2 are joined by the solder 12. When melting the solder 12, it is preheated (for example, 12
Solder 1 by heating at a temperature of 0 ° C to 160 ° C)
I am familiar with 2.

This preliminary heating lowers the viscosity of the solder 12 and spreads it on the electrode land 3, and further spreads the solder 12 that has entered below the chip component 10. After preheating, main heating (for example, 2
(Heating at a temperature of about 00 ° C to 240 ° C) is performed to completely melt the solder 12. By this main heating, the electrode portion 11 of the chip component 10 and the electrode land 3 of the printed wiring board 1 are soldered, but at the same time, the solder 12 that has entered below the chip component 10 is also melted and solder balls are formed. 12a is formed. This solder ball 12a
Is separated from the solder 12 on the electrode land 3 and remains on the solder resist 4.

[0008]

However, as shown in FIG. 5 (c).
The solder ball 12a as shown in FIG. 1 not only spoils the finished appearance of the soldering, but also separates from the electrode land 3 and easily peels off when some force such as vibration or twist is applied to the substrate 2, It may enter between the terminals of chip parts and cause an electrical short circuit. As a result, the reliability of the electronic device or the like is significantly reduced.

[0009]

SUMMARY OF THE INVENTION The present invention is a chip component mounting board and a chip component mounting method, which have been made to solve such problems. That is, the present invention provides a substrate for mounting a chip component, provided on the substrate, a printed wiring board having an electrode land to be bonded to the electrode portions of the chip component through solder, placed Be done
Predetermined wiring pattern on the substrate below the chip component
Is provided and a part of the wiring pattern is used as an electrode land.
Also serves as a land for solder adsorption with a predetermined interval between
The land for solder adsorption and the
And solder land on the area other than the area corresponding to the electrode land
No solder resist is applied.

In addition, in the mounting method of the above chip component,
A predetermined amount of paste solder on the electrode land.
The bottom half of the electrode part of the chip component.
By embedding it in the solder on the
Melting the solder melts the solder on the electrode land
The solder that protrudes from the electrode land.
The process of adsorbing to the solder adsorption land that is a part of the turn
By cooling and solidifying the solder,
And fixed to the suction land.
A process to separate and fix the solder from the solder on the electrode land side.
It is also a method of mounting a chip part having the following features.

[0011]

In the printed wiring board of the present invention, the solder adsorption lands are provided at a predetermined distance from the electrode lands. Therefore, the solder crushed when mounting the chip component and protruding from the electrode lands is It comes into contact with the solder adsorption land. The state in which the solder contacting the solder adsorption land is separated into the electrode land side and the solder adsorption land side by the function of the surface tension and the solder adhesion force when the solder is melted, and is soldered to this solder adsorption land. Fixed by.

Further, a wiring pattern is provided on the substrate below the mounted chip component, and a part of the wiring pattern is also used as a solder adsorption land, so that this wiring pattern is not only used for signal conduction but also protruded. It can also be used for solder adsorption. At this time, by applying the solder resist that does not adhere to the solder to the area on the substrate except the area corresponding to the solder adsorption land and the electrode land, the melted solder is surely separated without adhering to the solder resist. , Is in a state of being bonded and fixed to the solder suction land.

Further, by providing a through hole in the solder suction land, the solder protruding from the electrode land is
At the time of melting, it is drawn toward the solder adsorption land side and is drawn into the through hole by the capillary phenomenon. For this reason, the suction force of the solder protruding from the electrode land to the solder adsorption land is increased, and it is possible to suppress the ball state.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view for explaining the present invention , (a) is a perspective view and (b) is a plan view. That is, the chip of the present invention
The mounting board of the component is for mounting a chip component 10 including a resistor and a capacitor on the printed wiring board 1 by soldering to form a predetermined circuit. It is composed of an electrode land 3 which is joined via solder and a solder adsorption land 5 which is provided in the vicinity of the electrode land 3.

Further, a solder resist 4 to which no solder adheres is adhered to the area of the substrate 2 other than the upper portions of the electrode lands 3 and the solder adsorption lands 5, and the solder adheres to unnecessary portions to electrically conduct. This prevents a short circuit.

The solder adsorption lands 5 are arranged in a state of slightly protruding from the lower side of the chip component 10 to be placed, and with a predetermined distance d from the electrode lands 3. In the soldering of the chip component 10 which will be described later, this interval d is a land for solder adsorption when the solder applied to the electrode land 3 protrudes from the electrode land 3 by mounting the chip component 10 (including protrusion by preheating). The distance (for example, about 0.2 mm) is set so that the solder can be separated from the electrode land 3 side and the solder suction land 5 side by the surface tension and the solder adhesion force in a molten state. I'll do it.

Next, switch of the present invention based on the sectional view of FIG. 2
The mounting method of the plug-in component will be described. First, as shown in FIG. 2A, a predetermined amount of paste-like solder 12 is applied onto the electrode lands 3 provided on the substrate 2 of the printed wiring board 1 by a screen printing method or the like. Then, in this state, the chip component 10 is held by a suction collet or the like (not shown),
The chip component 10 is arranged above the electrode land 3.

Next, as shown in FIG. 2B, the chip component 10 is pressed against the substrate 2 side so that the lower half of the electrode portion 11 is embedded in the solder 12. At this time, the paste-like solder 12 is crushed and sticks out of the electrode land 3, and also enters the lower side of the chip component 10. The protruding solder 12 spreads along the solder resist 4 on the substrate 2 and comes into contact with (or reaches close to) the solder adsorption land 5.

Next, as shown in FIG. 2 (c), the printed wiring board 1 on which the chip components 10 are mounted is preheated and main-heated by passing through a reflow oven or the like, and the solder 1 is applied.
Melt 2. The solder 12 that has been crushed and squeezed out of the electrode land 3 has a reduced viscosity due to preheating, and comes into contact with the solder adsorption land 5 even when it reaches near the solder adsorption land 5.

Further, when the solder 12 is completely melted by the main heating, the surface tension and the solder adhesion force act to separate the electrode land 3 side and the solder adsorption land 5 side. That is, the solder 12 becomes in a liquid phase and its surface tension increases, and the adhesive force with the metal (so-called solder wettability) increases, so that the solder 12 does not adhere to the electrode resist 3 side. The solder adsorption land 5 is separated and attached.

By cooling and solidifying the solder 12 in this state, the electrode portion 11 of the chip component 10 and the electrode land 3 of the printed wiring board 1 are soldered, and the separated solder 12 is placed on the solder adsorption land 5. It will become stuck. As a result, the solder 1 protruding from the electrode land 3
The balls 2 are fixed on the solder suction land 5 without remaining on the solder resist 4 in the form of balls, and are not easily peeled off even when a force such as vibration or twist is applied to the substrate 2.

As shown in FIG. 1B, two solder adsorption lands 5 are provided between the two electrode lands 3 when the chip component 10 is mounted. This is because it is considered that the solder 12 protrudes from both sides.

Next, another example of the present invention will be described with reference to the schematic plan view of FIG. In the example shown in FIG. 3 (a), the solder adsorption lands 5 protrude from the electrode lands 3 and the solder 12 extends.
It shows a case where the area is the minimum necessary to adsorb (see FIG. 2B). The solder adsorption land 5 may have any shape as long as it has an area capable of adsorbing and holding the solder 12 (see FIG. 2B) protruding in this manner. It is necessary to keep the distance as explained above. That is, by keeping this distance d, the solder 12 (see FIG.
Of the electrode land 3 and the solder adsorption land 5 due to the surface tension and the solder adhesion force when they can contact and melt.
After soldering, solder 1
2 does not cause a bridge between the electrode land 3 and the solder suction land 5.

In the example shown in FIG. 3B, a predetermined wiring is provided on the substrate 2 between the two electrode lands 3, that is, below the mounted chip component 10 (see the chain double-dashed line in the figure). A pattern 6 is provided, and a part of the wiring pattern 6 is also used as the solder adsorption land 5. Moreover, the solder resist 4 is deposited on the areas other than the areas corresponding to the solder suction lands 5 and the electrode lands 3, so that unnecessary solder adhesion can be prevented.

The wiring pattern 6 is used as a normal signal conducting line, and the solder resist 4 is conventionally deposited on the entire wiring pattern 6. In the present embodiment, a portion of the solder resist 4 corresponding to the solder adsorption land 5 of the wiring pattern 6 is opened, so that the wiring pattern 6 is used for signal conduction and the solder 12 protruding from the electrode land 3 (see FIG. 2 (b)), so that it can also be used for adhesion.

When the wiring pattern 6 is provided below the chip component 10 to be placed, it is possible to open the solder resist 4 in the corresponding area without newly installing the solder adsorption land 5. A part of the wiring pattern 6 can be used as the solder suction land 5.

The example shown in FIG. 3C is a combination of the above two examples (examples shown in FIGS. 3A and 3B), and a part of the wiring pattern 6 is solder-adsorbed. The solder adsorption land 5 is used as the soldering land 5, and the solder adsorption land 5 has a minimum necessary area capable of sucking the solder 12 (see FIG. 2B) protruding from the electrode land 3. Moreover, the solder resist 4 in the region corresponding to the upper side of the solder suction land 5 is opened. As a result, the electrode land 3
The distance d between the solder suction land 5 and the solder suction land 5 can be positively adjusted, and the wiring pattern 6 can be used for signal conduction and solder suction.

Next, an example in which the through holes 7 are provided in the solder adsorption lands 5 will be described with reference to the schematic plan view of FIG.
That is, FIG. 4A shows an example in which the through hole 7 is provided substantially in the center of the solder adsorption land 5 provided individually, and FIG.
Shows an example in which a part of the wiring pattern 6 is used as a solder adsorption land 5 and a through hole 7 is provided substantially in the center thereof.

As described above, by providing the solder adsorption land 5, the solder 1 protruding from the electrode land 3 is formed.
When 2 (see FIG. 2B) is melted, the surface tension and the solder adhering force cause the electrode land 3 side and the solder adsorption land 5 side to be separated and adsorbed.

At this time, since the solder adsorption land 5 is provided with the through hole 7 having a predetermined depth, the solder 12 adsorbed to the solder adsorption land 5 side is drawn into the through hole 7 by the capillary phenomenon. become. That is,
By pulling the solder 12 into the through hole 7, the solder suction capacity of the solder suction land 5 increases and the solder suction force increases, and the solder 12 protruding from the electrode land 3 can be reliably separated and joined. .

Moreover, the amount of the solder 12 remaining on the surface of the solder suction land 5 is reduced by drawing the solder 12 into the through hole 7, and it becomes difficult to form solder balls. This makes it possible to obtain a sufficient suction force for the solder 12 that has overflowed. The depth of the through hole 7 may be halfway through the substrate 2 or may penetrate the substrate 2, and may be determined according to the adsorption capacity of the solder 12.

[0032]

As described above, the tip portion of the present invention
According to the mounting board of the product and the mounting method of the chip component, the following effects can be obtained. That is, in the present invention, since the solder suction land is provided on the substrate, the solder protruding from the electrode land can be securely sucked and held. In addition, it is not necessary to provide a new solder adsorption land by using it as a wiring pattern, and by providing a through hole in the solder adsorption land, the solder adsorption force increases and more reliable solder adsorption and holding can be realized. become. For this reason, even if a force such as vibration or twist is applied to the substrate, the protruding solder does not easily fall off, and it is possible to improve the electrical reliability. By using the present invention as described above, it is possible to provide a highly reliable electronic device.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating the present invention , in which (a) is a perspective view,
(B) is a plan view.

FIG. 2 is a cross-sectional view illustrating a bonding state of chip components in the order of (a) to (c).

FIG. 3 is a schematic plan view illustrating another example.

FIG. 4 is a schematic plan view illustrating an example in which a through hole is provided.

FIG. 5 is a cross-sectional view illustrating a conventional example.

[Explanation of symbols]

1 printed wiring board 2 substrates 3 electrode land 4 Solder resist 5 Solder land 10 Chip parts 11 Electrode part

Claims (3)

(57) [Claims] 1. A mounting board for a chip component, comprising a substrate for mounting the chip component, and an electrode land provided on the substrate and joined to an electrode portion of the chip component via solder. On the substrate below the chip component to be placed.
A fixed wiring pattern is provided and one of the wiring patterns is
Part with a predetermined distance from the electrode land
It also serves as a suction land, and on the board, the solder suction land and the electrode
Solder does not adhere to areas other than the area corresponding to
A mounting board for chip parts, characterized in that a solder resist is applied . 2. A claims, characterized in that said the through hole of a predetermined depth in the solder adsorption land is provided
A mounting board for the chip component according to 1 . 3. A mounting board for a chip component according to claim 1.
In the mounting method of the chip component used, a step of applying a predetermined amount of paste-like solder on the electrode land, and then embedding the lower half of the electrode part of the chip component in the solder on the electrode land, Melting the solder by heating to melt the solder on the electrode lands and adsorb the solder protruding from the electrode lands to the solder adsorption lands that are a part of the wiring pattern ; A step of fixing the chip component and the electrode land by cooling and solidifying the solder, and separating and fixing the solder adsorbed to the adsorption land from the electrode land side solder. Characteristic chip component mounting method.