JP2008066344A - Multilayer board, and printing method of metal bonding material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide solder coating to a multilayer board capable of coating the cavity structure section of the multilayer board with solder efficiently, and to provide a method for coating the multilayer board with solder. <P>SOLUTION: In the printing method of a metal bonding material to the multilayer board, a recess penetrating a middle layer from a part surface or a solder surface is provided. The printing method comprises: a process for providing a hole section and a mask section for printing a metal bonding material on wiring on the surface of the part surface or solder surface of the multilayer board on the multilayer board, and setting a metal mask where a projecting fitted into the recess for adhering the metal bonding material is provided to wiring that is nearly as high as the height (depth) of the recess and is provided on the bottom surface at least from the recess opening to the side; a process for painting the metal bonding material to the metal mask set to the multilayer board; and a process for removing the metal mask. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to surface mounting on a printed wiring board, and more particularly to a technology for mounting high-density components on a multilayer printed wiring board (multilayer board).

  In recent years, in a printed wiring board (hereinafter referred to as a board) mounting field, a board having a concavo-convex structure on a component mounting surface (cavity structure board) has been used around a camera lens or in a vehicle. For example, the component 7 is inserted into the concave portion (cavity structure portion) of the substrate 1 shown in FIG. 8, the wire bonding connection location with the land 4 on the substrate 1, the electrode 14 of the other component 8, etc. The mixed mounting in which the solder connection part 15 exists is the mainstream. However, since it is necessary to provide a second lead portion for wire bonding connection, the design of parts around it is limited, and it is difficult to further increase the density.

Therefore, Patent Documents 1 to 5 propose a technique that does not use wire bonding connection in order to increase the density with respect to the above problems.
According to Patent Document 1, in order to realize a state where an SMD component is mounted on a small and short substrate, a recess in which the SMD type component can be dropped is provided on the substrate at a position where the SMD type component is disposed. A conductor is placed in the portion of the side wall of the recess corresponding to the terminal portion of the SMD type component, and the terminal portion of the SMD type component and the inner side surface conductor of the recess of the substrate are connected by soldering. Have been proposed to include SMD type parts.

  According to Patent Document 2, in order to reduce the size of the substrate and increase the mounting density of the electronic component elements, there is a printed wiring board on which the electronic component elements are mounted and has concave portions exposed on the surface or voids formed inside. In the printed wiring board having an interlayer connection circuit on the side surface of the recess or gap, or having a recess exposed on the surface or a gap formed inside, the side surface of the recess or gap There has been a proposal to provide a connection terminal for an electronic component element.

Further, Patent Documents 3, 4, and 5 also propose proposals in which components are arranged in the recesses of the board.
However, although the methods proposed in Patent Documents 1 to 5 can increase the density, a method for applying solder to the concave portion is not described. In addition, since the conventional solder application method is not a method of applying all the soldered portions at once, work such as reapplying solder to the bottom of the concave portion occurs, and the number of preparation steps before component mounting is large. There's a problem.
Japanese Patent Laid-Open No. 08-130356 JP 2002-319745 A Japanese Patent Laid-Open No. 02-224293 JP 09-199824 A JP 62-262490 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide solder application to a multilayer substrate and a method thereof capable of efficiently applying solder to a cavity structure portion of the multilayer substrate. .

  A multilayer substrate provided with a recess penetrating from a component surface or a solder surface to an intermediate layer, which is one aspect of the present invention, and a metal bonding material is attached to a wiring provided on a bottom portion from an opening of the recess through a side surface Structure.

  Preferably, the metal bonding material is attached to the wiring disposed on the side surface of the recess from the surface of the component surface or the solder surface, or is adhered to the wiring disposed on the bottom portion via the side surface. May be.

Preferably, the bonding material may be cream solder.
With the above configuration, the number of cream solder printing steps can be shortened by applying a metal bonding material (such as cream solder) to the wiring on the substrate surface and the side surfaces and bottom of the recess at a time. In addition, since the wire bonding method is not required, the connection portion (second lead portion) that restricts the design of the peripheral portion is also unnecessary, and further high-density mounting is possible.

  A method for printing a metal bonding material on a multilayer substrate provided with a recess penetrating from a component surface or a solder surface to an intermediate layer according to the present invention, wherein the metal bonding material is applied to the multilayer substrate on the component surface or the solder of the multilayer substrate. A hole and a mask for printing the metal bonding material are provided on the wiring on the surface of the surface, and is substantially the same as the height of the recess, and is provided at the bottom via at least the side from the recess opening A step of setting a metal mask provided with a convex portion to be fitted in the concave portion for attaching the metal bonding material to the wiring, and a step of applying a metal bonding material to the metal mask set on the multilayer substrate. And removing the metal mask.

The number of cream solder printing steps can be shortened by applying the metal bonding material (such as cream solder) to the wiring on the substrate surface and the wiring on the side surface and the bottom of the recess at a time.
The present invention also relates to a method for printing a metal bonding material on a multilayer substrate provided with a recess penetrating from a component surface or a solder surface to a middle layer according to the present invention, wherein the metal bonding material is applied to the multilayer substrate on the component surface or the multilayer substrate. A hole and a mask for printing on the wiring on the surface of the solder surface are provided, and a metal mask provided with the recess side surface printing hole on which the metal bonding material hangs down and adheres to the side surface of the recess is set. And a step of applying a metal bonding material to the metal mask set on the multilayer substrate, and a step of removing the metal mask.

  By applying the metal bonding material (such as cream solder) to the wiring on the substrate surface and the wiring on the side surface of the concave portion as described above, the number of cream solder printing processes can be shortened.

  According to the present invention, the process can be shortened by applying the metal bonding material from the wiring on the substrate surface to the side surface and the bottom of the recess at a time. In addition, this mounting method enables high-density mounting.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Basic structure)
FIG. 1 is a diagram showing a principle structure when solder is applied to a multilayer board according to the present invention. For example, as shown in FIGS. 1A and 1B, a metal bonding material (cream solder, conductive paste, etc.) is applied. After that, the surface mounting component is mounted in FIG. In this example, the first layer 1, the second layer 2, and the third layer 3 are used from the component side of the multilayer board. Further, although there may be a plurality of layers up to the solder surface, they are omitted here. Further, in this example, the wiring 4 is provided from the upper surface of the first layer 1 to the upper surface of the second layer 2 so as to follow the first layer wall surface of the recess 6. And the cream solder 5 (metal bonding material) is apply | coated to the multilayer substrate of such a structure. At this time, the cream solder 5 is applied on the wiring 4 in the recess 6 so as to have the shape shown in FIG. Further, it is applied in the shape shown in FIG. Thereafter, as shown in FIG. 1C, the surface mount components 7 and 8 are mounted.

  In addition, as shown in FIG. 2, wiring 10 (for example, copper wiring) and wiring 4 are connected by vias 9 between the respective layers. Further, wiring 4 (for example, copper wiring) may be provided on the component surface of the first layer 1 and the upper surface (first layer bottom surface) of the second layer 2.

Further, the surface mount components 7 and 8 have a configuration in which electrode portions are provided at both ends of the component main body. In this example, a surface-mounted component 8 that is generally mounted on the component surface and a surface-mounted component 7 that is housed in the recess 6 (cavity portion) of the multilayer substrate are shown separately. The recess 6 may penetrate from the component surface or the solder surface of the multilayer substrate to the middle layer.
(Example 1)
(Description of metal mask)
When the cream solder 5 is applied to the concave portion 6 of the multilayer substrate (cavity structure substrate), normally, only the surface layer of the component surface of the first layer is initially applied to only the surface layer (other than the bottom and side surfaces (wall surface) of the concave portion 6). The cream solder 5 is applied using the hole 11 and the mask 12 of the metal mask. Thereafter, an appropriate amount of cream solder 5 is applied to the bottom of the recess 6 with a dispenser or the like, and then the component is mounted on the component surface of the first layer following the recess.

  As shown in FIG. 2A, the metal mask of the present invention is substantially the same as the height of the recess 6 (depth), unlike the structure of a normal metal mask, and the wiring 4 (land) on the bottom and side surfaces of the recess 6. ) Is provided between the holes 11 so as to project the optimal cream solder 5. The convex portion 13 is substantially the same as the height of the concave portion 6, and the cream solder 5 is attached to the target wiring provided at the bottom portion through at least the side surface from the opening (upper portion) of the concave portion 6. As shown in FIG. 2C, the cream solder 5 does not have to be applied to all portions on the bottom wiring 4, and may be applied partially.

  Here, the optimum application amount is an amount that the cream solder 5 does not flow to at least other wiring portions (different signal lines and power supply lines) when the mounting component is mounted. Similarly, the amount of cream solder 5 does not flow to other wiring portions during reflow.

By providing the convex portion 13, it becomes possible to complete the application of the cream solder once (one step). (The components are then mounted.)
(Description of solder application process)
A process of applying the cream solder 5 using a metal mask in the case of mounting a surface mounting component will be described.

FIG. 2 shows the manufacturing process. This process diagram shows the process until the component mounting is completed on the multilayer board (cavity structure board).
In step S11, the multilayer board is set in the component mounting apparatus (see FIG. 2A). Although the multilayer substrate is not described in detail here, it has a configuration similar to that of the substrate described in FIG. In addition, the metal mask of the present invention manufactured according to the mounting component is set on the land portion of the wiring 4 wired on the multilayer substrate.

  In step S12 (solder application step), as shown in FIG. 2B, the cream solder 5 is printed in the concave portion in which the mounted component is accommodated in the first layer 1. Cream solder 5 is applied from the surface wiring 4 of the first layer 1 to the wiring 4 on the side surface of the recess 6 and the wiring 4 on the upper surface of the second layer 2 (bottom surface of the first layer 1).

In step S13 (metal mask removing step), as shown in FIG. 2C, the metal mask of the present invention is lifted upward to remove the metal mask.
In step S14 (component mounting step), mounting components are mounted as shown in FIG. Here, in step S14, description has been made using surface mount components having a general chip resistor shape and chip capacitor shape, but the type of component is not limited as long as it can be mounted.

Next, in step S15, reflow is performed as shown in FIG.
With the above configuration, it is possible to achieve higher density mounting than in the past, and it is possible to apply cream solder to the recesses at a time, so that the number of manufacturing processes for mounting components can be reduced.
(Example 2)
Next, the structure of the metal mask and the solder coating process of Example 2 will be described.

  The structure of the metal mask of Example 2 is shown in FIG. Holes 11 (recessed side surface printing holes) are provided in the metal mask so that cream solder can be applied to both ends of the recessed portion 6 and the side wiring 4 of the multilayer substrate.

The hole 11 is opened, for example, on the wiring 4 wired on the bottom from the surface of the first layer of the multilayer substrate through the side surface of the recess 6.
Next, as shown in FIG. 3A, the metal mask having the above structure is set on the multilayer substrate, and the cream solder 5 is printed.

Then, as shown in FIG. 3B, the cream solder 5 hangs down and adheres to the wiring 4 on the side surface of the recess 6.
Thereafter, the mounting component is mounted in the same manner as in the first embodiment and reflowed to complete the soldering.

In this embodiment, the cream solder 5 is attached to the side surface of the recess 6, but the hole 11 may be manufactured so that the cream solder 5 is attached to the bottom.
In the printing application method of the first and second embodiments, all the printing methods using a metal mask are included, and the solder filling method in the metal mask such as the squeegee method and the press-fitting method is not limited.
(Modification)
As shown in FIG. 4, cream solder may be applied by a dispensing method, and the cream solder may be applied to the wiring 4 disposed at the bottom from the surface of both ends of the opening of the recess 6 through the side surface.

Moreover, you may apply | coat cream solder to the wiring 4 arrange | positioned through the side surface from the both-ends surface of the opening part of the recessed part 6 using the metal jet type solder application apparatus shown in FIG.
Furthermore, you may mount after apply | coating the cream solder shown in FIG. 6 to the electrode part of components.

Alternatively, cream solder may be applied in advance to the wiring 4 at both ends of the opening of the recess 6 shown in FIG. 7, and flux (bonding material) may be applied and mounted on the electrode surface of the component when mounting the component.
Note that the solder applied by the transfer and metal jet application methods may be land on the same wiring pattern on the bottom surface of the substrate cavity structure due to variations in application, excessive soldering, and changes over time.

  The present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the gist of the present invention.

It is a structural diagram showing the basic structure of solder printing and component mounting. It is structural drawing which shows the process outline of cream solder printing and component mounting. FIG. 6 is a structural diagram showing the solder printing (immediately after printing) of Example 2 and the state of solder after solder printing. It is a structural diagram which shows solder application by the dispensing method. It is a structural view showing solder application by a metal jet method. It is a structural diagram in the case where solder is pre-applied to the electrodes of the mounting component to mount the mounting component. It is a structural diagram in the case of mounting a mounting component by applying a bonding material to an electrode of the mounting component. It is a structural diagram in the case of mounting components on a conventional cavity structure board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st layer, 2nd layer, 3rd 3rd layer 4 Wiring (use place at the time of soldering), 5 Cream solder (solder), 6 Recessed part 7 Mounted part (recessed part), 8 Mounted part (surface)
9 Via, 10 Wiring (inner layer of substrate)
11 Hole part, 12 Mask part, 13 Convex part 14 Mounting part electrode part 15 Wiring (Used part at the time of wire bonding: Second lead part)

Claims (5)

A multilayer board provided with a recess penetrating from the component surface or the solder surface to the middle layer,
A multi-layer substrate, wherein a metal bonding material is attached to a wiring provided on a bottom portion through a side surface from an opening portion of the concave portion.   The metal bonding material is attached to the wiring disposed on the side surface of the recess from the surface of a component surface or a solder surface, or is adhered to the wiring disposed on the bottom portion through the side surface. The multilayer substrate according to claim 1.   The multilayer substrate according to claim 1, wherein the bonding material is cream solder. A method of printing a metal bonding material on a multilayer substrate provided with a recess penetrating from a component surface or a solder surface to a middle layer,
The multilayer substrate is provided with a hole and a mask for printing the metal bonding material on the wiring on the component surface or the solder surface of the multilayer substrate, and the height (depth) of the recess. A metal mask provided with a convex portion that fits into the concave portion for adhering the metal bonding material to a target wiring provided at the bottom portion through a side surface from the concave portion opening portion. Setting process;
Applying a metal bonding material to the metal mask set on the multilayer substrate;
Removing the metal mask;
A method for printing a metal bonding material on a multilayer substrate. A method of printing a metal bonding material on a multilayer substrate provided with a recess penetrating from a component surface or a solder surface to a middle layer,
The multilayer substrate is provided with a hole and a mask portion for printing the metal bonding material on the component surface of the multilayer substrate or the wiring on the surface of the solder surface, and the metal bonding material hangs down on the side surface of the recess. A step of setting a metal mask provided with the concave side surface printing hole to be adhered;
Applying a metal bonding material to the metal mask set on the multilayer substrate;
Removing the metal mask;
A method for printing a metal bonding material on a multilayer substrate.