JPH05347473A - Wiring substrate - Google Patents

Abstract

PURPOSE:To enable good package of a multi-terminal electronic part by dividing an electrode pad into two or more and by forming a division band of a material whose wettability is lower than that of a material of the electrode pad. CONSTITUTION:A plurality of electrode pads 16 are provided to a wiring substrate 15. The electrode pad 16 is formed of a material of good soldering wettability such as copper, gold, solder and tin. A division band 17 for dividing the electrode pad 16 into two in a width direction is provided on each electrode pad 16 all over an entire length of the electrode pad 16. The division band 17 is formed of insulating resin such as photoresist whose solder wettability is lower than that of a material of the electrode pad 16. Since a soldering material supplied onto the electrode pad 16 can be thereby divided into two, a lower side of a terminal of a multi-terminal electronic part can be held stably and the multi-terminal electronic part can be packaged well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board on which electronic parts are mounted.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, there is a mounting process for mounting a multi-terminal electronic component on a wiring board.

For example, as a multi-terminal electronic component, a flat package (SOP (Small Ou)
t-line Packege)) is mounted on a wiring board.

As shown in FIG. 6, a wiring pattern (not shown) corresponding to each terminal 3 of the SOP 1 is formed on the wiring board 2 on which the SOP 1 is mounted.
Electrode pads 5 having a width corresponding to the width of the terminal 3 are provided at positions where the electrodes abut. Then, on the electrode pad 5, a solder material 6 as a bonding material is previously supplied for convenience of mounting. Next, the supply of the solder material 6 will be described in more detail with reference to FIG.

First, as shown in FIG. 1A, paste-shaped solder 7 (hereinafter referred to as paste solder 7) is printed and supplied onto the electrode pad 5 by using a screen printing means. To do. Then, this wiring board 5 is heated to
The solder 7 is melted. As a result, the paste solder 7 becomes a semi-cylindrical solder material 6 due to surface tension, as shown in FIG. Then, by cooling the wiring board 2, the solder material 6 is hardened in the above-mentioned kamaboko state.

The wiring board 5 to which the solder material 6 has been previously supplied in this manner is transferred to the component mounting apparatus. Next, as shown in FIG. 6, the SOP 1 suction-held by the suction nozzle 9 is mounted on the wiring board 2. As shown in FIG. 5B, this SOP 1 is connected to the terminals 3
... are aligned with the electrode pads 5, and the lower surface of each terminal 3 is placed in contact with the upper surface of the solder material 6.

Then, as shown in FIG. 5 (c), the terminals 3 ... Are pressed by the bonding tool 10 toward the wiring board 2 and heated. As a result, the solder material 6 is melted, and the terminals 3 and the electrode pads 5 are connected via the solder material 6.

[0008]

By the way, as described above, the solder material 6 preliminarily supplied on the electrode pad 5 is hardened in a semicylindrical shape due to surface tension. Therefore, when the bonding tool 10 pressurizes the terminal 3, the terminal 3 is pressed before the solder material 6 is melted.
May be displaced and deformed in the lateral direction (for example, the direction indicated by the arrow (a) in FIG. 5C) along the curved surface of the solder material 6. It is conceivable that if the terminals 3 are connected in a deformed state, the connection strength becomes weak and the terminals 3 come into contact with the adjacent terminals 3 to cause defective conduction.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a wiring board in which terminals of a multi-terminal electronic component are reliably connected to electrode pads via a solder material. To do.

[0010]

A first means of the present invention is a wiring board on which a multi-terminal electronic component is mounted, the electrode having a width corresponding to the width of the terminals of the multi-terminal electronic component. It is characterized by including a pad and at least two divisions of the electrode pad, and a division band made of a material having a lower wettability than the material of the electrode pad.

A second means is a wiring board on which a multi-terminal electronic component is mounted, the electrode pad having a width corresponding to the width of the terminals of the multi-terminal electronic component, and at least two electrode pads. It is characterized in that it is provided with a groove portion divided into the above.

[0012]

According to this structure, the solder material supplied onto each electrode pad of this wiring board is melted,
It is divided into two or more with a dividing band or groove as a boundary.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same components as those of the conventional example are designated by the same reference numerals, and the description thereof will be omitted. First, a first embodiment will be described with reference to FIGS. 1 and 2.

FIG. 1 shows a wiring board 15 of the present invention.
Is. This wiring board 15 has an SO
Width corresponding to the width of the terminals 3 of P1 (for example, 300 μm)
Are provided with the plurality of electrode pads 16 ... The electrode pad 16 is formed of a material having good solder wettability, such as copper, gold, solder, tin or the like.

On each electrode pad 16, a dividing band 17 that divides the electrode pad 16 into two in the width direction is provided over the entire length of the electrode pad 16. The divided band 17 is made of an insulating resin having poor solder wettability, such as photoresist. In addition, this division band 17
Has a width of, for example, about 100 μm.

Dividing band 17 made of this photoresist
When the wiring pattern is formed on the wiring board 15, is formed by a method such as exposure and etching as in the case of the wiring pattern. Next, on the wiring board 5, the S
A case of mounting OP1 will be described with reference to FIG.

First, a solder material is supplied onto the electrode pad 16. (A) is a state before the solder material 6 is supplied. On the electrode pad 16 and the division band 17,
By screen printing, the paste solder 7 is printed and supplied as shown in FIG.

Next, the wiring board 15 is heated to melt the paste solder 7. Then, as shown in (c), the paste solder 7 is divided into two parts by the effect of surface tension at the dividing band (photoresist) having poor solder wettability, and is cooled, so that each of them has a semi-cylindrical shape. It becomes the solder material 6 and is hardened.

When the solder material 6 is supplied onto each electrode pad 16 in this manner, the wiring board 15 is transferred onto a bonding stage (not shown) of the electronic component mounting apparatus.

Then, on the wiring board 15, as shown by citing FIG. 6, the SOP 1 whose upper surface is adsorbed and held by the adsorption nozzle 9 has each terminal 3 ...
And the lower surface of the terminal 3 is brought into contact with the solder material 6 and mounted on the wiring board 15.

Then, as shown in (d), the pressing surface (lower end surface) of the bonding tool 10 is positioned above the terminal 3, and the bonding tool 10 is heated and driven downward. And this bonding tool 10
The pressing surface of is contacted with the upper surface of the terminal 3, and the bonding tool 10 presses the terminal 3 toward the wiring board 15 to heat it.

At this time, since the lower surface of the terminal 3 is in contact with the solder materials 6 and 6 which are divided into two as described above and hardened into a semi-cylindrical shape at two points (lines) A and A, the terminal 3 is stably held. Even if it is pressed downward, it is unlikely to be displaced from this position as in the conventional example.

Therefore, in this state, the terminal 3 is surely pressed against the solder material 6, and the solder material 6
Is melted, the terminal 3 is bonded to the electrode pad 16 via the solder material 6.

According to such a structure, the paste solder 7 (solder material 6) supplied onto the electrode pad 16 is divided into two by dividing the electrode pad 16 with a material having poor wettability. Therefore, it is possible to stably hold the lower surface of the terminal 3 of the SOP1. As a result, it is possible to obtain the wiring board 15 in which the SOP1 can be mounted well.

Next, a second embodiment of the present invention will be described with reference to FIG.
A description will be given with reference to (a). The electrode pad 20 of the second embodiment is composed of a member 20a having good solder wettability, such as copper,
A dissimilar metal strip 20b having poor solder wettability such as zinc, stainless steel, or aluminum is provided between the strips 20a.

According to this structure, by melting the paste solder printed and supplied, the solder material 6 is divided into two parts with the dissimilar metal strip 20b as a boundary, which is different from the first embodiment. The same effect can be obtained. Next, a third embodiment will be described.

The electrode pad 22 of the third embodiment is formed of a material having good solder wettability, such as copper, and the central portion of the electrode pad 22 in the width direction has a groove portion for dividing the electrode pad into two. 23 is formed over the entire length of the electrode pad 22.

According to this structure, since the solder material 6 does not adhere to the groove portion 23, the solder material 6 is divided into two with the groove portion 23 as a boundary. As a result, the same effect as that of the first embodiment can be obtained. In addition,
The present invention is not limited to the above embodiment,
Various modifications can be made without changing the gist of the invention.

In the above-described embodiment, the division band 17 is provided over the entire length of the electrode pad 16, but the present invention is not limited to this, and as shown in FIG. It is also possible to provide a plurality of strip-shaped divided bands 17 at predetermined intervals along the length direction. In addition, FIG.
As shown in FIG. 5, the division band 17 may be provided only in the central portion of the electrode pad 16 in the length direction.

Further, in the above-described embodiment, the solder material is divided into two by the one division band 17, but the invention is not limited to this, and the electrode pad 16 is not limited thereto.
The electrode pad 16 may be divided into three parts by providing two or more rows in the width direction. The point is that the supplied solder material 6 can stably hold the lower surface of the terminal 3 at at least two contact points (lines).

The division band 17 and the electrode pad 1 are
The material of No. 6 is not limited to the one given in the above-mentioned embodiment, but is determined by the material of the solder material 6. For a specific solder material 6, the division band 17 is used as the electrode pad 16. Any material that has poor solder wettability may be used. For example, the division band 17 may be solder resist, silk printing, or the like.

Further, in the above-mentioned one embodiment, the SOP1 is taken as an example of the mounted multi-terminal electronic component, but the present invention is not limited to this, and other multi-terminal electronic components, for example,
It may be QFP (Quad Flat Packege) or the like.

[0033]

As described above, the first structure of the present invention is a wiring board on which a multi-terminal electronic component is mounted,
An electrode pad formed with a width corresponding to the width of the terminals of the multi-terminal electronic component, and the electrode pad is divided into at least two or more, and is formed of a material having a wettability lower than that of the electrode pad. And a belt.

The second structure is a wiring board on which a multi-terminal electronic component is mounted, and an electrode pad formed with a width corresponding to the width of the terminals of the multi-terminal electronic component, and the electrode pad. And a groove portion divided into at least two or more.

According to this structure, when the solder material is supplied onto the electrode pad and the dividing strips or the groove portion, the solder material is divided into two or more with the dividing body and the groove portion as boundaries. As a result, the terminals of the multi-terminal electronic component can be stably held at at least two points (lines) or more, so that the terminals can be effectively prevented from being displaced during bonding, and connection defects can be reduced. There is an effect.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2A to FIG. 2D are process diagrams of mounting a multi-terminal electronic component on a wiring board in the same manner.

3A and 3B are vertical cross-sectional views showing electrode pads of the second and third embodiments.

4A and 4B are plan views showing electrode pads of another embodiment.

5A to 5C are process diagrams for mounting a multi-terminal electronic component on a conventional wiring board.

FIG. 6 is a perspective view showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... SOP (multi-terminal electronic component), 3 ... Terminal, 15 ... Wiring board, 16 ... Electrode pad, 17 ... Dividing band, 20 ... Electrode pad, 20b ... Dissimilar metal strip (dividing band), 22 ... Electrode pad, 23 … Groove.

Claims (2)

[Claims] 1. A wiring board on which a multi-terminal electronic component is mounted, the electrode pad having a width corresponding to the width of a terminal of the multi-terminal electronic component, and the electrode pad is divided into at least two or more parts. In addition, the wiring board is provided with a division band formed of a material having a poorer wettability than the material of the electrode pad. 2. A wiring board on which a multi-terminal electronic component is mounted, the electrode pad having a width corresponding to the width of the terminals of the multi-terminal electronic component, and the electrode pad is divided into at least two or more parts. A wiring board comprising: a groove.