JP2002353578A - Substrate for surface-mounted component, and method of mounting the surface-mounted component on substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect nondissolved state and defective wetting of solder, without having to use inspection method which utilizes X-rays, etc. SOLUTION: On a substrate 11, mounting position indicating marks 14 indicating the mounting position A of surface-mounted component 1 are provided, and at the same time, position deviation indicating marks 15 are provided on the outsides of the makes 14. The components 1 are mounted on the substrate 11, in a state where the component 1 are positionally deviated from the position A and heated. Consequently, solder balls 13 provided on the component 1 melt and join parts-side electrodes 2 and substrate-side electrodes 13 to each other. At the same time, self-alignment action is generated and the parts 1 can be moved to the mounting position A. Therefore, whether or not the solder balls 3 melt and joint the electrodes 2 and 13 to each other can be checked, by identifying whether or not the marks 14 are visible, after the electrodes 2 and 13 are jointed to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount component substrate suitable for mounting a surface mount component on a substrate by soldering, and a method of mounting the surface mount component on the substrate.

[0002]

2. Description of the Related Art Generally, a BGA (Ball Grid Array),
A surface mount component called a CSP (Chip Size Package) has a large number of solder balls mounted on the bonding surface side (back side) with a substrate, and is mounted by melting and bonding the solder balls to the electrodes of the substrate. is there. Here, in the prior art, after the surface-mounted component is mounted by soldering, the solder material joining the substrate and the surface-mounted component is in a state sandwiched between the substrate and the surface-mounted component. The joint state of the solder material cannot be confirmed visually or the like from the surface side of the mounted component. For this reason, in the prior art, in order to reliably melt the solder material for joining the substrate and the surface mount component, for example, a thermocouple is provided on the substrate or the like, and the temperature is controlled, and inspection using, for example, X-rays or the like is performed. The quality of the product was controlled by confirming the bonding state of the solder material by the method.

[0003]

However, in the above-mentioned prior art, a special inspection method using X-rays or the like is used to control the temperature of a substrate or the like using a thermocouple or to confirm the state of soldering. However, expensive inspection equipment is required, and a certain amount of time is required for inspection and preparation thereof, resulting in reduced productivity.

In the inspection method using X-rays as in the prior art, X-rays are irradiated from the surface side of the surface-mounted component,
The bonding state of the solder material is confirmed by transmission or reflection of the X-ray. For this reason, in such an inspection method, although it can be identified that the solder material is disposed between the component-side electrode of the surface mount component and the board-side electrode of the board, whether or not the solder material is melted by heating is determined. There is a problem that it is not possible to inspect whether or not the melted solder material has joined to the component-side electrode and the board-side electrode (solder material wetting failure).

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a surface capable of detecting unmelted solder and poor wetting without using an inspection method using X-rays or the like. An object of the present invention is to provide a mounting component substrate and a method of mounting a surface mounting component on the substrate.

[0006]

In order to solve the above-mentioned problems, a substrate for a surface mount component according to the invention of claim 1 comprises:
A substrate on which the surface mount component is mounted, a mounting position indicating mark provided on the substrate and indicating a normal mounting position when the surface mounting component is mounted, and provided on the substrate at a position apart from the mounting position indicating mark And a positional deviation amount indicating mark indicating the amount of positional deviation of the surface-mounted component from a regular mounting position.

[0007] With this configuration, when mounting the surface mount component on the substrate, the surface mount component is placed on the substrate in a state of being intentionally displaced from the proper mounting position. At this time, a solder material is attached to at least one of the component side electrode of the surface mount component and the board side electrode of the board. In addition, when the surface-mounted component is displaced, a part of the mounting position indicating mark is covered by the surface-mounted component, and thus becomes invisible. Next, the substrate and the surface mount component are heated by a heating furnace or the like to melt the solder material. At this time, the solder material is melted while being in contact with the component-side electrode and the board-side electrode, but tends to be deformed into a substantially spherical shape by the surface tension. Therefore, with the deformation of the solder material, the surface-mounted component is displaced to a position where the component-side electrode and the board-side electrode face each other at the shortest distance, and the normal mounting position where the component-side electrode and the board-side electrode face each other. (The self-alignment action).

As a result, when the solder material is melted, the surface-mounted component moves to the mounting position and the mounting position indicating mark becomes visible. When the solder material is not melted, the surface-mounted component keeps its position shifted. As a result, a part of the mounting position marking mark becomes invisible. For this reason, it is possible to inspect the bonding state of the solder material by identifying whether or not the entire mounting position indicating mark can be visually checked after bonding the surface mount components.

In addition, since the substrate is provided with a displacement amount indicating mark indicating the amount of displacement of the surface-mounted component from the mounting position, the surface-mounted component is excessively displaced from the mounting position before heating the substrate or the like. It can be inspected in advance whether or not it is arranged on the substrate in the state. That is, if the amount of displacement of the surface-mounted component is too large, the self-alignment action does not occur even when the solder material is melted, and the surface-mounted component may not move. However, in the present invention, the amount of displacement of the substrate can be grasped by the displacement amount indicating mark, and an excessive displacement of the surface mount component can be inspected in advance.

In this case, a substrate-side electrode is provided on the front side of the substrate, and a component-side electrode is provided on the back side of the surface-mounted component. Is the normal mounting position when facing.

According to a third aspect of the present invention, there is provided a method of mounting a surface-mounted component on a substrate, wherein the substrate is provided with a substrate-side electrode on the front surface, and the component-side electrode is provided on a back surface facing the front surface of the substrate. Surface mounting component, a solder material provided on at least one of the substrate-side electrode and the component-side electrode, and a mounting indicating a regular mounting position when mounting the surface mounting component provided on the substrate. A position indicating mark, the surface-mounted component is mounted on the substrate in a state of being displaced from a regular mounting position, the substrate and the surface-mounted component are heated to melt the solder material, Another object of the present invention is to provide a configuration in which a surface-mounted component is mounted on a substrate by cooling and solidifying a solder material after the mounted component has moved to a proper mounting position.

With this configuration, when mounting the surface-mounted component on the substrate, the surface-mounted component is mounted on the substrate in a state of being displaced from the mounting position. Next, the substrate and the surface mount component are heated by a heating furnace or the like to melt the solder material. At this time, the solder material is melted while being in contact with the component-side electrode and the board-side electrode, but tends to be deformed into a substantially spherical shape by the surface tension. For this reason, the self-alignment action occurs with the deformation of the solder material, so that the surface-mounted component can be moved to the regular mounting position.

Further, when the surface mount component is mounted on the substrate, the mounting position mark is partially covered with the surface mount component and cannot be viewed. On the other hand, when the self-alignment action occurs due to the melting of the solder material, the surface-mounted component moves to the proper mounting position and the mounting position indication mark becomes visible. With the position shifted, a part of the mounting position marking mark becomes invisible. For this reason, it is possible to inspect the bonding state of the solder material by identifying whether or not the entire mounting position indicating mark can be visually checked after bonding the surface mount components.

According to the present invention, a solder ball is provided as a solder material on the component-side electrode, and the maximum displacement of the surface-mounted component with respect to the substrate is set to substantially half the diameter of the solder ball. are doing.

Thus, the solder ball can be brought into contact with the substrate-side electrode, and the self-alignment action can be reliably generated by melting the solder ball, so that the surface-mounted component can be moved to the proper mounting position.

Further, according to the present invention, the maximum displacement of the surface-mounted component with respect to the substrate is set to substantially half the electrode diameter of the component-side electrode of the surface-mounted component.

As a result, excessive displacement can be prevented, and the self-alignment action can be reliably generated by melting the solder material, so that the surface-mounted component can be moved to the proper mounting position.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a substrate for a surface mount component according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. First, the surface mount components mounted on the surface mount component substrate will be described.

Reference numeral 1 denotes a surface-mounted component mounted on a substrate 11, which will be described later. The surface-mounted component 1 is formed of an insulating resin material or the like into a substantially rectangular plate shape, and performs IC, LSI, etc. (Not shown). And
The surface mount component 1 has a back surface 1 </ b> A facing the substrate 11 forming a bonding surface to be bonded to the substrate 11.

Reference numeral 2 denotes a plurality of component-side electrodes provided on the back surface 1A of the surface-mounted component 1. The component-side electrodes 2 are formed of a copper thin film or the like, and have a circle having, for example, an electrode diameter L1 (diameter). It is formed by the shape. And the component side electrode 2
Is bonded to the substrate-side electrode 13 of the substrate 11 by melting a solder ball 3 described later.

Reference numeral 3 denotes a back surface 1A of the surface-mounted component 1 which is located on the inner side (center side) of the outer peripheral end surface 1B of the surface-mounted component 1.
The solder ball 3 is formed in a substantially hemispherical shape having a diameter L2 of about 0.5 mm, for example.

Next, a description will be given of a surface mounting component substrate according to the present embodiment on which the above-described surface mounting component 1 is mounted.

Reference numeral 11 denotes a substrate formed of, for example, a substantially rectangular plate. The substrate 11 is formed of an insulating resin material, and its surface 11A has various components 12 on which a terminal connection state can be visually observed. Are mounted, and the surface-mounted component 1 in which the bonding state of the component-side electrode 2 is invisible is mounted.

Reference numeral 13 denotes a substrate-side electrode provided on the surface 11A side of the substrate 11. The substrate-side electrode 13 is formed of a copper thin film or the like, and has, for example, a circular shape having substantially the same size as the component-side electrode 2. No. And the substrate side electrode 13
When the surface mount component 1 is mounted, it is arranged at a position where it can face the component side electrode 2.

Reference numeral 14 denotes a mounting position indicating mark provided on the front surface 11A side of the substrate 11, and the mounting position indicating mark 14
Are formed by silk printing, a copper thin film, or the like, and are provided at a total of two positions, for example, at both ends of a diagonal line of the surface mounting component 1 having a substantially square shape. The mounting position indicating mark 14 is a regular mounting position A where the substrate-side electrode 13 of the substrate 11 and the component-side electrode 2 of the surface mount component 1 face each other.
When the surface mount component 1 is mounted at the mounting position A, the surface mount component 1 extends in a substantially L shape along the outer peripheral end surface 1B of the surface mount component 1. Then, the mounting position indicating mark 14
Is arranged slightly outside of the mounting position A so that the entire surface mounting component 1 can be viewed in a state where the surface mounting component 1 is mounted at the mounting position A.

Reference numeral 15 denotes a displacement amount marking mark provided at a total of two positions corresponding to the mounting position marking mark 14 on the front surface 11A side of the substrate 11, and the displacement amount marking mark 15 is a mounting position marking mark. Like the mark 14, it is formed by silk printing or the like, is provided at a position away from the mounting position indicating mark 14 (mounting position A), and extends in a substantially L-shape in parallel with the mounting position indicating mark 14. I have. The positional deviation amount mark 15 has a gap ε of, for example, about 0.1 to 0.2 mm between the position deviation mark 15 and the mounting position mark 14. Accordingly, the positional displacement amount indicating mark 15 is positioned when the surface mount component 1 is displaced and placed on the board 11 in order to solder the component-side electrode 2 to the board-side electrode 13 as described later. This shows the amount of deviation.

The gap ε between the positional displacement amount marking mark 15 and the mounting position marking mark 14 is, for example, a length dimension (about half the diameter L 2 of the solder ball 3) as the maximum positional displacement amount of the surface mount component 1. L2 / 2).

The surface mounting component substrate according to the present embodiment has the above-described configuration. Next, a mounting method for mounting the surface mounting component 1 on the surface mounting component substrate will be described with reference to FIGS. It will be explained while doing.

First, a mask (not shown) is attached to the entire surface 11A of the substrate 11 shown in FIGS. Then, as shown in FIG. 5, cream solder 16 as a solder material in which solder and flux are kneaded is printed (applied) on the substrate-side electrode 13 of the substrate 11 through a mask. Note that a flux alone may be applied instead of the cream solder 16.

Next, as shown in FIGS.
The surface mount component 1 is placed on the front surface 11A of the first device 11 using a mounter (not shown) in a state of being displaced. At this time,
The positional deviation dimension δ1 between the center of the component-side electrode 2 and the center of the substrate-side electrode 13 is a value smaller than the maximum positional deviation amount.
For example, approximately half the diameter L2 of the solder ball 3 (L2 /
Set the value within 2) to about 0.15 to 0.2 mm. As a result, the solder ball 3 comes into contact with the cream solder 16 on the substrate-side electrode 13 and is fixed. Further, one of the two mounting position indicating marks 14 is the surface mount component 1.
And become invisible.

In this case, since the positional deviation amount indicating mark 15 is provided on the substrate 11, it can be inspected whether or not the surface mounted component 1 is disposed on the substrate 11 in a state of being excessively displaced from the mounting position A. . That is, when the positional deviation amount δ1 of the surface mount component 1 is too large, the positional deviation amount indicating mark 15 in addition to the mounting position indicating mark 14 becomes invisible. For this reason, the position deviation amount δ1 can be inspected by confirming whether or not the position deviation amount indicating mark 15 is visible.

Next, as shown in FIGS. 9 and 10, the substrate 11 and the surface mount component 1 are inserted into a heating furnace (not shown) and heated to melt the solder balls 3 and the cream solder 16 together. Then, the component-side electrode 2 and the board-side electrode 13 are joined by the solder 17. At this time, although the solder 17 is melted while being in contact with the component-side electrode 2 and the board-side electrode 13, the solder 17 tends to be deformed into a substantially spherical shape due to the surface tension. For this reason, the self-alignment action occurs due to the deformation of the solder 17, and the surface-mounted component 1 has the component-side electrode 2 and the board-side electrode 1.
3 is displaced to the position facing the shortest distance, and the component side electrode 2
And the substrate-side electrode 13 are moved to a mounting position where they face each other.

As a result, when the solder ball 3 is melted, the surface mount component 1 moves to the mounting position and the mounting position mark 14 becomes visible. When the solder ball 3 does not melt, the surface mount component 1 is displaced. In this state, a part of the mounting position mark 14 becomes invisible. For this reason, the bonding state of the solder 17 can be inspected by identifying whether or not the entire mounting position indicating mark 14 can be visually checked after bonding the surface mount component 1.

Thus, in the present embodiment, since the mounting position indicating mark 14 is provided on the substrate 11, the surface mounting component 1 placed with a displacement with respect to the substrate 11 is heated, and then the entire mounting position indicating mark 14 is heated. It is possible to inspect whether or not the solder ball 3 is melted and the component-side electrode 2 and the board-side electrode 13 are joined by confirming whether or not is visible. For this reason, it is possible to detect the unmelted or wet defect of the solder ball 3 without using an inspection method using X-rays or the like, and it is possible to improve productivity.

Further, since the board 11 is provided with the mark 15 for indicating the amount of misalignment, before heating the board 11 or the like, it is inspected whether or not the surface mount component 1 is excessively misaligned from the regular mounting position A. be able to. As a result, an excessive displacement can be inspected in advance, and a defective connection between the surface mount component 1 and the substrate 11 due to the excessive displacement can be prevented.

Further, since the maximum displacement amount of the surface-mounted component 1 is set to substantially half the diameter L 2 of the solder ball 3, excessive displacement is prevented, and the solder ball 3 is moved to the substrate side electrode 13. (Cream solder 16). As a result, by melting the solder ball 3, the melted solder 17 is transferred to the component-side electrode 2 and the board-side electrode 1.
3 can be reliably brought into contact with each other, a self-alignment action can be generated, and the surface mount component 1 can be moved to the regular mounting position A.

In the above-described embodiment, the substantially L-shaped mounting position indicating mark 14 and the positional deviation amount indicating mark 15 are provided at two positions on both ends of the diagonal line of the surface mount component 1, respectively. For example, a configuration may be adopted in which a mounting position indicating mark and a positional deviation amount indicating mark are provided at all four corner corners, and a substantially square mounting position indicating mark and a positional deviation amount indicating mark are provided so as to surround the surface-mounted component 1. It may be configured.

In the case where the precision of the mounter for mounting the surface mount component 1 on the substrate 11 is high, the first type shown in FIG.
As in the modified example, the configuration may be such that the displacement amount indicating mark 15 is omitted.

As shown in a second modified example shown in FIG.
Two misregistration amount marking marks 1 with an approximate gap interval
5 'may be provided, or three or more displacement amount indicating marks may be provided.

Further, in the above-described embodiment, the case where the solder ball 3 as a solder material is provided on the component side electrode 2 has been described. However, the cream solder is provided on the board side electrode 13 without providing the solder material on the component side electrode 2. 16 'etc. solder material is provided,
The surface mount component 1 may be configured to be joined to the substrate 11.

As described above, the solder balls 3 are attached to the surface mount component 1.
In the case of bonding to the substrate 11 in a state in which no solder is attached, for example, cream solder 16 as a relatively large amount of solder material is attached to the substrate-side electrode 13 of the substrate 11 as in a third modification shown in FIGS. 'And apply the cream solder 16'
To the component side electrode 2. In this state, the substrate 11 and the surface-mounted component 1 are heated to cause a self-alignment action, and the component-side electrode 2 and the substrate-side electrode 13 can be joined by the solder 17 ′. In this case, the misalignment dimension δ2 between the center of the component side electrode 2 and the center of the board side electrode 13
Is set to a value smaller than the maximum displacement amount, for example, to a value that is within approximately half (L1 / 2) of the electrode diameter L1 of the component-side electrode 2.

Accordingly, the gap ε between the positional displacement amount marking mark 15 and the mounting position marking mark 14 is, for example, approximately half of the electrode diameter L 1 of the component side electrode 2 as the maximum positional displacement amount of the surface mount component 1. It may be set to the length dimension (L1 / 2).

In the above embodiment, the component-side electrode 2 and the substrate-side electrode 13 are formed in a substantially circular shape, but may be formed in a polygonal shape such as a square shape.

[0044]

As described above in detail, according to the first aspect of the present invention, since the mounting position indicating mark is provided on the substrate, the surface mounted components mounted in a state of being displaced with respect to the substrate heat these components. After that, it can be confirmed whether or not it has moved to the regular mounting position by checking whether or not the entire mounting position indicating mark is visible. For this reason, it is possible to inspect whether or not the solder material has melted and the component-side electrode and the board-side electrode have been joined by visually observing the mounting position indicating mark. Without using it, it is possible to detect unmelted solder material and poor wettability, thereby improving productivity.

Further, since the substrate is provided with the displacement amount indicating mark, it is possible to inspect whether or not the surface-mounted component is excessively displaced from the mounting position before heating the substrate or the like. As a result, a self-alignment effect does not occur due to an excessive displacement, and it is possible to prevent a bonding failure between the surface mount component and the substrate from occurring.

In this case, a board-side electrode is provided on the front side of the board, and a component-side electrode is provided on the back side of the surface-mounted component. Is the correct mounting position.

According to the third aspect of the present invention, the surface mount component is placed on the substrate in a state of being shifted from the mounting position,
Since the substrate and the surface-mounted component are heated in this state, a self-alignment action can be generated with the melting of the solder material, and the surface-mounted component can be moved to the mounting position.

When the surface-mounted component is placed on the substrate with its position shifted, the mounting position marking mark is partially covered by the surface-mounted component and cannot be seen, whereas the self-alignment effect is not achieved. When this occurs, the surface mount component moves to the mounting position, and the entire mounting position indicating mark becomes visible. Therefore, by identifying whether or not the entire mounting position marking mark can be visually checked after joining the surface mount components, it is possible to inspect whether or not the self-alignment action has occurred and the solder material has been joined.

According to the fourth aspect of the present invention, a solder ball is provided as a solder material on the component side electrode, and the maximum displacement of the surface mounted component with respect to the substrate is substantially half the diameter of the solder ball. Therefore, the solder ball can be brought into contact with the substrate-side electrode, and the self-alignment action can be reliably generated by melting the solder ball.

Further, according to the fifth aspect of the present invention, since the maximum displacement of the surface-mounted component is set to substantially half the electrode diameter of the component-side electrode of the surface-mounted component, excessive displacement can be prevented. By melting the solder material, a self-alignment action can be reliably generated, and the surface-mounted component can be moved to a regular mounting position.

[Brief description of the drawings]

FIG. 1 is a plan view showing a state where a surface mount component is joined to a substrate according to an embodiment.

FIG. 2 is an exploded perspective view showing a state in which a substrate and a surface mount component are separated.

FIG. 3 is an enlarged plan view showing the substrate according to the embodiment alone;

FIG. 4 is a sectional view of the substrate in FIG. 3 as seen from the direction of arrows IV-IV.

FIG. 5 is a cross-sectional view showing a state where cream solder is applied to a substrate-side electrode.

FIG. 6 is an enlarged plan view showing a state in which the surface-mounted component is displaced and mounted on a substrate.

FIG. 7 is an enlarged plan view of a main part showing a periphery of a mounting position indicating mark, a positional deviation amount indicating mark, and the like in FIG. 6;

FIG. 8 shows the substrate and the surface mount components in FIG. 7 by arrows VIII-VIII.
It is sectional drawing seen from the direction.

FIG. 9 is a cross-sectional view showing a state where the substrate and the surface-mounted component are joined by heating.

FIG. 10 is an enlarged plan view of a main part showing a periphery of a mounting position indicating mark, a positional deviation amount indicating mark, and the like in a state where the surface mounting component is bonded to the substrate.

FIG. 11 is an enlarged plan view showing a substrate according to a first modification.

FIG. 12 is an enlarged plan view showing a substrate according to a second modification.

FIG. 13 is a cross-sectional view showing a state where cream solder is applied to a substrate-side electrode of a substrate according to a third modification.

14 is a cross-sectional view showing a state where a surface mount substrate is mounted on the substrate of FIG.

FIG. 15 is a cross-sectional view showing a state where a surface-mounted component is heated and joined to a substrate according to a third modified example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Surface mount component 2 Component side electrode 3 Solder ball (solder material) 11 Substrate 13 Board side electrode 14 Mounting position indicating mark 15, 15 'Position shift amount indicating mark 16, 16' Cream solder (solder material) A Component mounting position

Claims (5)

[Claims] 1. A substrate on which a surface mount component is mounted, a mount position mark provided on the substrate and indicating a regular mount position when the surface mount component is mounted, and a position distant from the mount position mark And a positional displacement amount indicating mark provided on the substrate and indicating the amount by which the surface mounted component is displaced from a regular mounting position. 2. A board-side electrode is provided on a front side of the board, and a component-side electrode is provided on a back side of the surface-mounted component.
The surface mount component substrate according to claim 1, wherein the normal mounting position is when the substrate-side electrode and the component-side electrode face each other. 3. A substrate having a substrate-side electrode provided on a front surface thereof, a surface-mounted component having a component-side electrode provided on a back surface facing the front surface of the substrate, and the substrate-side electrode and the component-side electrode. A solder material provided on at least one side thereof, and a mounting position indicating mark indicating a normal mounting position when mounting the surface mounted component provided on the substrate, wherein the surface mounted component is provided on the substrate. It is mounted in a state where it is displaced from the regular mounting position, the substrate and the surface mounted component are heated to melt the solder material, and the solder material is cooled and solidified after the surface mounted component is moved to the regular mounting position. And mounting the surface-mounted component on the board by mounting the surface-mounted component on the board. 4. The component-side electrode according to claim 3, wherein a solder ball is provided as a solder material, and a maximum displacement of the surface-mounted component with respect to the substrate is substantially half a diameter of the solder ball. Method of mounting surface mount components on a PCB. 5. The mounting of a surface-mounted component on a substrate according to claim 3, wherein the maximum displacement of the surface-mounted component with respect to the substrate is substantially half the electrode diameter of a component-side electrode of the surface-mounted component. Method.