JPH0682929B2 - Multilayer printed wiring board for mounting surface mount components - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer layer and an inner layer.
The surface mounting component board that has a path and electronic components are mounted on the surface.
A multilayer printed wiring board for mounting , in particular , an outer layer conductor
A non-penetrating via that electrically connects the circuit and the conductor circuit in the inner layer.
-Hole and surface mount part for mounting the electronic parts
The present invention relates to a multilayer printed wiring board having a flat electrode for connecting products .

[0002]

2. Description of the Related Art In a conventional multilayer printed wiring board having non-penetrating holes, that is, non-penetrating through-holes, as shown in FIG. An efficient method was taken.

However, when a non-through through hole is formed by drilling with a drill, it is naturally necessary to control the depth of the drill in the thickness direction of the multilayer board. The variation of the plate thickness of itself is unavoidable, and the distance h between the bottom of the non-penetrating through hole shown in FIG. 5 and the conductor of the next layer varies depending on the method of drilling work. For this reason, in a conventional multilayer printed wiring board provided with non-through holes by drilling, there is a drawback that the electrical characteristics of the conductor change significantly,
Further, since the residence time of the drill becomes long at the bottom of the non-penetrating through hole, there is a drawback that smear which adversely affects the through hole increases.

Further, in laser drilling, the number of steps for providing a non-through through hole after removing the outermost copper foil by etching is increased, and in this laser drilling, the hole wall of the non-through through hole is increased. There is a drawback that the roughness becomes large.

Therefore, as a method for eliminating these defects, as disclosed in Japanese Patent Laid-Open No. 195796/1984, "There is a through hole in an insulating plate and a conductor circuit pattern is previously formed only on one surface. The two formed insulating plates are arranged on the outermost layer with the conductor circuit patterns facing each other.
After combination through a prepreg, heating and pressurization to form a multilayer substrate, through holes are provided, and after copper plating is performed on the entire surface, a conductor circuit pattern of the outermost layer is formed. " However, with this conventional method,
As shown in FIG. 7 after "copper plating on the entire surface", the resin surface filled in the non-penetrating through holes and the copper plating have poor adhesion, and as they are, when mounting the components. Since the copper plating and the resin are peeled off and swelled, the copper plating on the resin surface filled in the non-penetrating through holes must be removed by etching as shown in FIGS. 6 and 7. It was.

If the copper plating on the resin surface filled in the non-penetrating through holes is removed as described above, the non-penetrating through holes cannot be used as a flat electrode at all, and high density wiring is achieved. Not only is it impossible to perform the mounting, but it may also result in a multilayer printed wiring board that cannot be mounted with components. Because,
Many electronic components to be mounted on this type of multilayer printed wiring board are for surface mounting that uses so-called solder to make electrical connections, and if there is a hole in the center of the electrode, this hole Solder flows into the inside to make a reliable electrical connection, and it cannot be used at all as an electrode for wire bonding.

That is, in the multilayer printed wiring board manufactured by the above-mentioned method, since the conductor layer is not formed on the resin surface filled in the non-through holes, the flat package used for surface mounting, etc. When soldering the leads of the electronic component, since the non-penetrating through hole is provided in the electrode portion, uniform soldering on the entire surface of the electrode portion is difficult, and the reliability of component mounting decreases. However, it cannot be used as an electrode for wire bonding at all.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to provide (on the non-penetrating through hole, stable electrical characteristics, (EN) A multilayer printed wiring board having a flat electrode (having high reliability of component mounting and high reliability of wire bonding) and having high wiring flexibility.

[0009]

In order to solve the above problems BRIEF SUMMARY OF THE INVENTION, means of adopting the present invention is explained with reference numeral used in the examples, the "outer layer of the conductor circuit 21, this
The inner conductor layer disposed under the outer conductor circuit 21 of
The path 22, the conductor circuit 22 of the inner layer and the conductor circuit of the outer layer
A first insulating layer 31 narrowly provided between the channel 21 and
Conductors of other layers arranged below the conductor circuit 22 of the layer
The body circuit 23, the conductor circuit 23 of the other layer and the inner layer
A multilayer printed wiring board 10 of the surface mount component mounted thereon and a second insulating layer 32 which is Sema設between the conductive circuit 2 2, formed surface mounted on conductor circuit 21 of the outer layer
Plane electrode 15 for connecting parts and the back side of this plane electrode 15
And through-hole plating on the inner wall 1
4a is formed and the conductor circuit 21 of the outer layer and the conductor circuit 21 of the inner layer are formed.
Non-penetrating through-hole 1 for electrically connecting to body circuit 22
4 and the non-penetrating through hole 14 is filled with the flat
The second insulating layer 3 adhered to the surface electrode 15 on the roughened surface
And a resin 13a forming part 2
It is a multilayer printed wiring board 10 for mounting surface mount components .

Next, this structure will be described in more detail with reference to the drawings. First, FIG. 1 shows a partially enlarged vertical sectional view of a multilayer printed wiring board 10 according to the present invention. In this multilayer printed wiring board 10 , the inner peripheral wall is provided on the surface layer portion.
Through-hole plating 14a is formed on the outer conductor circuit
21 is formed with a non-penetrating through hole 14 for electrically connecting the conductor circuit 22 of the inner layer, and the resin 13 forming the second insulating layer 32 is formed in the non-penetrating through hole 14.
The planar electrode 15 is formed in a state of being filled with a and closing the non-through hole 14.

Such a multilayer printed wiring board 10 is formed, for example, as follows. That is, first, the through hole (through hole plating 14a is formed on the inner peripheral wall,
A printed wiring board (in the state shown in FIG. 2 ) having a through hole which will later become the non-through hole 14 is provided on one side of the outer layer substrate 11 (one of the insulating materials which becomes the first insulating layer 31 later ) .
Conductor circuit is formed in advance on the surface to become the inner layer conductor circuit 22.
The other surface has copper plating and etch
Substrate on which the conductor circuit 21 of the outer layer is formed by the processing
Used as a prepreg 13 (later with the second insulating layer 32).
Inner layer substrate 12 (both sides of the insulating material)
A conductor circuit is formed in advance so as to become the conductor circuit 23 of another layer.
After being laminated and integrated (the state shown in FIG. 3 ) with the formed substrate , a through hole for the through hole 16 is formed. Then, in order to improve the adhesion between the surface of the resin 13a filled in the non-penetrating through holes 14 and the copper plating 15a to be formed later, the surface of the resin 13a filled in the non-penetrating through holes 14 is mechanically attached. Or chemical treatment,
Particularly, by polishing, the surplus resin is removed and the surface of the resin 13a is made flat.
Roughen the surface of. Then, through-hole plating is performed in the through-holes for the through-holes 16 and copper plating 15a including the surface of the roughened resin 13a is formed, and then the non-through-holes 1 filled with the resin 13a are formed.
4 and the copper plating 15a to be the outer-layer conductor circuit 21 of a desired shape is left, and the remaining portion is subjected to etching treatment. As a result, the non-penetrating through hole 14 is filled with the resin 13a, the surface of the resin 13a is a rough surface, and the surface of the resin 13a and its periphery are the planar electrodes 15 connected to the leads of the electronic component. Thus, the multilayer printed wiring board 10 is completed.

The method of roughening the surface of the resin 13a may be either mechanical treatment or chemical treatment. For example, liquid honing can be used as the mechanical treatment. As the chemical treatment, a method of treating with permanganate is suitable. By performing the above processing, the resin 1
The surface of 3a is appropriately roughened so that the non-through hole 1
The multilayer printed wiring board 10 having sufficient adhesion between the resin 13a filled in the resin layer 4 and the copper plating 15a to be the planar electrode 15.
Therefore, the multilayer printed wiring board 10 has no problem in mounting components or wire bonding.

[0013]

The present invention has the following effects by adopting the above means.

In the multilayer printed wiring board 10 according to the present invention, the non-penetrating through hole 14 is filled with the resin 13a, and the planar electrode 1 of the conductor circuit 21 of the outer layer is formed on the resin 13a.
5, that is, the copper plating 15a is formed, so that, for example, when a lead of a flat package or the like is soldered to the planar electrode 15, the connection area for soldering the entire surface of the lead and the planar electrode 15 increases, and the connection reliability is increased. The sex is also increasing. In addition, this flat electrode 15
Even when wire-bonding to
The plane electrode 15 is sufficiently flat and has a sufficiently large area.

That is, in the multilayer printed wiring board 10 according to the present invention, the upper surface of the resin 13a in the non-penetrating through hole 14 located below the plane electrode 15 is
Since it becomes the planar electrode 15 (on which the metal plating layer, that is, the copper plating 15a is formed), the non-penetrating through hole 14 is sufficiently securely electrically connected to the through hole plating, and is completely planarized. is there. Therefore, the plane electrode 15 formed of the metal plating layer, that is, the copper plating 15a is not only electrically connected to the non-penetrating through hole 14 reliably, but also for component mounting or wire bonding. It has a sufficient flatness and area.

Furthermore, the multilayer printed wiring board 10 of the present invention.
For example, even in the case of manufacturing by the method described above,
It may be difficult to align the copper plating 15a on the surface of the resin 13a filled in the non-through holes 14 by etching, and the connection reliability of the non-through holes 14 may decrease due to overetching. This is preferable because the reliability of the electrical connection between the conductor circuit 21 in the outer layer and the non-through hole 14 can be increased.

In other words, in the multilayer printed wiring board 10 according to the present invention, by making the surface of the resin 13a filled in the non-through holes 14 into a suitable roughened surface, the resin 13a and a flat surface can be obtained. A multilayer printed wiring board 1 which has sufficient adhesion to the copper plating 15a to be the electrode 15 and has no problem in mounting surface mounting components such as a flat package or wire bonding.
It can be zero.

[0018]

EXAMPLES Next, the present invention will be explained by examples.

[0019] Example 1 hole by drilling a hole with a diameter of 0.3 mm at a predetermined position of the glass epoxy copper-clad laminate testimony was subjected to copper plating on the entire surface by known chemical copper plating and electrolytic copper plating, the inner layer of the conductor a pattern of a predetermined shape comprising the circuit 22 is formed on one side of the substrate by etching, the inner peripheral
Through-hole plating 14a is formed on the wall and non-penetrating through
A printed wiring board (outer layer substrate 11) having through holes to be the holes 14 is obtained. Next, the outer layer substrate 11 and the inner layer substrate 12 on which a desired pattern is formed in advance to become the conductor circuits 23 of the other layers are formed into the second insulating layer 32.
That glass epoxy prepreg 13 through laminating, heating, to obtain a multi-layer plate under pressure. (At this time, the outer layer substrate 11
The inside of the through hole of the prepreg 13 is completely filled with the resin 13a, which makes the outer layer substrate 1
The through hole 1 is a non-penetrating through hole 14. )

After the holes to be the desired through holes 16 are drilled in the multilayer board obtained as described above, the excess resin 13a and the burrs flowing out from the through holes of the outer layer substrate 11 are removed by a belt. Remove by sanding. Then, the surface of the resin 13a filled in the through hole of the outer layer substrate 11 is roughened by liquid honing. Next, chemical copper plating and electrolytic copper plating are performed to form metal plating (copper plating 15a) to be the outer conductor circuit 21 and the flat electrode 15 on each outer layer substrate 11 on the outer layer substrate 11 (FIG. 1). reference). Then, the metal plating (copper plating 15a) is subjected to an etching treatment to form a predetermined outer layer conductor circuit 21 and the planar electrode 15 on the non-through hole 14.
A 6-layer multilayer printed wiring board 10 according to the present invention is obtained.

The hole by drilling a hole with a diameter of 0.25mm at a predetermined position of the second embodiment glass polyimide copper clad laminate facie showing, after 15μm thick with the copper plating on the entire surface by known chemical copper plating, the inner layer of conductor circuit 22 a pattern of a predetermined shape which is formed on one side of the substrate by tenting, inner
Through-hole plating 14a is formed on the surrounding wall
A printed wiring board (outer layer substrate 11) having through holes to be the through holes 14 is obtained. Next, the outer layer substrate 11 and the inner layer substrate 12 in which a desired pattern to be the conductor circuit 23 of the other layer is formed are provided with the glass polyimide prepreg 13 serving as the second insulating layer 32 interposed therebetween. Stacked, heated,
Press to obtain a multilayer board. (At this time, the inside of the through hole of the outer layer substrate 11 is completely filled with the resin 13a of the prepreg 13.) Next, a hole to be the through hole 16 having a diameter of 1.0 mm was drilled at a desired position. After that, excess resin 13a and holes that have flowed out from the non-through holes 14 of the outer layer substrate 11 are removed by belt sander polishing. After that, a permanganate treatment is performed so that the resin 13 filled in the non-penetrating through holes 14 is processed.
After roughening the surface of a, publicly known chemical copper plating and electrolytic copper plating are performed in the same manner as in Example 1, and then an etching treatment is performed to obtain a flat surface on the non-penetrating through holes 14 of the outer layer substrate 11. The electrode 15 and the conductor circuit 21 of the outer layer are formed to obtain the 6-layer multilayer printed wiring board 10 according to the present invention.

[0022]

As described in detail above, according to the present invention,
As illustrated in each of the above embodiments, the “ outer layer conductor circuit 21
Of the inner layer disposed below the outer conductor circuit 21.
The conductor circuit 22 and the conductor circuit 22 of the inner layer and the outer layer
A first insulating layer 31 narrowly provided between the conductor circuit 21 and
Others disposed further below the conductor circuit 22 in the inner layer
The conductor circuit 23 of one layer, and the conductor circuit 23 of another layer
Second insulating layer 3 narrowly provided between the inner conductor circuit 22
2. A multilayer printed wiring board for mounting surface mount components, comprising
10, the surface formed on the conductor circuit 21 of the outer layer.
Planar electrode 15 for connecting surface mount components, and this plane electrode 15
It is installed on the back side of the
And the inner conductor circuit 21 of the outer layer
Non-through through-hole for electrically connecting to the conductor circuit 22 of the layer
And the non-penetrating through hole 14
The second insulating layer adhered to the flat electrode 15 on the roughened surface
The resin 13a that constitutes the edge layer 32 is provided ", which allows the electrical connection between the non-through hole 14 that is a non-through hole and the planar electrode 15 formed thereon. A multilayer structure having high stability and a flat electrode 15 formed on the non-penetrating through-hole 14 but having a flat shape and a large area, which has high connection reliability for mounting components or bonding wires. It is possible to provide the printed wiring board 10 with high density and increased design freedom.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view of a multilayer printed wiring board according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing a state immediately before a printed wiring board having a through hole is integrated with a prepreg.

FIG. 3 is a partially enlarged cross-sectional view showing a state after the printed wiring board is integrated by a prepreg.

FIG. 4 is a partially enlarged cross-sectional view showing a non-penetrating through hole in a conventional multilayer printed wiring board formed by a drill or a laser.

FIG. 5 is a partial enlarged cross-sectional view showing a distance h between a bottom portion of a non-penetrating through hole and a conductor of the next layer in a conventional multilayer printed wiring board.

FIG. 6 is a partially enlarged sectional view of a conventional multilayer printed wiring board having a non-penetrating through hole.

FIG. 7 is a partially enlarged cross-sectional view of the multilayer printed wiring board before the state shown in FIG. 6 is obtained.

[Explanation of symbols]

10 Multilayer Printed Wiring Board 11 Outer Layer Substrate 12 Inner Layer Substrate 13 Prepreg 13a Resin 14 Non-Through Through Hole 14a Through Hole Plating 15 Planar Electrode 15a Copper Plating 16 Through Hole 21 Conductor Circuit 23 of Inner Layer 23 Conductor Circuit of Other Layer 23 31 First Insulating Layer 32 Second Insulating Layer

Claims (1)

[Claims] 1. A conductor circuit of an outer layer and a conductor circuit of the outer layer
Conductor circuit of the inner layer arranged in the lower layer and conductor circuit of this inner layer
First insulation narrowly provided between the path and the conductor circuit of the outer layer
Layer, and other disposed on a layer further below the conductor circuit of the inner layer
Of the conductor circuit of the other layer and the conductor circuit of the other layer
A table provided with a second insulating layer provided between the conductor circuit and the second insulating layer.
A multilayer printed wiring board for mounting surface mount components, comprising:
A flat surface for connecting surface mount components formed on the conductor circuit of the outer layer
The electrode and the inner surface of the flat electrode
Through-hole plating is formed on the peripheral wall,
Non-penetrating strip that electrically connects the circuit and the conductor circuit of the inner layer.
Before filling the through hole and this non-penetrating through hole
The second insulating layer adhered to the flat electrode with the roughened surface
A surface mount part, characterized by comprising:
Multilayer printed wiring board for product mounting.