JPS58134498A - Multilayer circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multilayer wiring board with sJgI reliability that ensures reliable connection between component lead wires and wiring patterns in an electrical component insertion portion.

In order to facilitate understanding of the present invention, a multilayer wiring board previously proposed by the present applicant will be described. This multilayer wiring board is manufactured by forming a first wiring pattern (2) made of conductive foil, for example, copper foil, on the - side of an insulating base material (1), as shown in Figure #I1, and then forming a first wiring pattern (2) made of conductive foil, for example, copper foil. A desired insulating resin layer (3) is formed except for the connection part (2a) of 2), and then a conductive foil, such as a copper foil, with an adhesive (4) applied to the back side is laminated and combined. selectively etching to form the second wiring pattern (5), and then attach the connection part (5a) of the wiring pattern (5) @2 to the adhesive hole (4) in the opening provided.
is removed, and an electrical component insertion hole (6) is drilled by pressing force so as to pass through the center of the connection part (2) of the wiring pattern (2) of @1 facing into the opening, and then Insert the lead (8) of the electrical component (7) into this insertion hole (6), and connect the lead (8), the connection part (2 and (il)) with solder or other conductive material (9). This multilayer wiring board has advantages over conventional multilayer wiring boards, such as being able to provide a highly accurate circuit and being manufactured at a low cost.

However, in this case, at the connecting portion of the wiring patterns (2) and (5) where the electrical component insertion hole (6) is formed, the upper layer wiring pattern (
The connecting portion (5) of 5) is formed into an annular shape having a rounded inner peripheral surface so as to surround the human hole (6). For this purpose, after forming the upper layer wiring pattern (5), the adhesive (4) facing the opening of the connection part (5a) is swollen with an organic solvent (removal liquid) K, or mechanically removed. When peeling is performed by brushing (activation of the upper surface of the connecting part (2a) of the newly opened lower layer), adhesive re-dissolution contamination occurs due to pooling of the peeling liquid, and mechanical brushing within the opening is caused by the presence of the peripheral wall. I can't do it satisfactorily,
Activation of the upper surface of the connecting portion (2m) was insufficient, resulting in insufficient electrical contact with the conductive substance (9), resulting in increased electrical resistance. For example, when filling the conductive material (9) with molten solder dip, air corrosion occurs inside the opening as shown in Figure 2.
)'s Mitsumaki, that is, Handa Kake, is inhibited, and furthermore, it is based on the melted Ushida Atsushi armpit! Connecting parts (5) Adhesive (4) K Residual gas, moisture, air bubbles, heat stress: 1 The conductive material (9) K has an adverse effect, i, Increased stress There was that.

The present invention solves the above-mentioned problems and further improves reliability.
The present invention provides a multilayer wiring board.

Embodiments of the multilayer wiring board according to the present invention will be described below with reference to the drawings.

FIG. 3 shows an embodiment of the present invention, which shows step J11K. In this example, as shown in FIG.
Alternatively, a flexible insulating substrate is also possible) Prepare a copper-clad laminate with a conductive foil, such as copper foil, coated on one main surface of 3υ, and selectively etch the copper foil to form a conductive foil pattern, i.e., wiring, as shown in Table 1. Form Bataan Shishi.

At this time, in order to improve the adhesion between the wiring pattern (2) and the insulating layer to be formed next, the wiring pattern 4 may be subjected to surface treatment. Surface treatments include, in addition to blackening treatment, chemical roughening treatment to form an oxide film of K CuOlCum0 on the surface, mechanical roughening treatment by sandblasting or pushing, and the like. Next, on the base &αυ including the first wiring patterns Q, an insulating layer (through) made of, for example, an ultraviolet curing resin is applied to the first wiring pattern (2).
The connecting portion (in the illustrated example 'l'11.

When forming this insulating layer (c), move the squeegee back and forth.
According to this method, even if the shoulder part of the first wiring pattern becomes a gap, the shadow part is sufficiently coated due to the reciprocating coating, resulting in an insulating layer without pinholes (c).
can be formed.

Next, as shown in Fig. 3C, the adhesive c is in a green hardened state on the back side! A conductive foil, such as a copper foil (c), with a rib attached is laminated onto the substrate (211) using a roll laminating device (for example, inserted between a pair of heated rolls heated to 180° C.). The adhesive (2) should not be exposed to the etching solution of the conductive foil (for example, copper foil) to be selectively etched later, but should be dissolved in an organic solvent, and curing energy such as a single beam or heat should be applied vertically. It has the property of three-dimensional hardening.

Next, as shown in the third diagram, the copper foil (1) is selectively etched using an aqueous solution of ferrous chloride (etching solution) to form the second conductive foil pattern (4). Form. At this time, the connection part (26m) with the second wiring (first wiring of the turn) (turn (2)) is not shaped with a closed inner peripheral surface (newly opened ring shape), but with the first wiring as shown in the figure. Wiring no. (connection i of turn (2) (22a)
For example, in the example shown in the figure, they are formed into a substantially semicircular shape so that they partially overlap. When selectively etching the stiff copper foil 4, the adhesive (2) on the back side is not removed.

Next, as shown in Fig. 3EK, both connections 5 (22 and (2)
6a) Solder resist layer (except for the part corresponding to K) (
2) is formed by printing. For this solder resist layer (2), an ultraviolet curing resin such as an epoxy acrylate resin can be used, and an organic resin used for peeling off the adhesive (goods) can be used. It has the property of not being affected by solvents.Then, the connection part (26 holes) between this solder resist layer fin and the second wiring pattern (2), that is, the copper foil, is used as an i-splash to connect the first wiring pattern (turn (2)). Connection part (22al)
K-corresponding part exposed green adhesive (goods)
is selectively dissolved and peeled off with an organic solvent (for example, a methylene chloride solution) to expose the surface of the connection (22).

Next, in this case, at least one@2 wiring I (a portion where the main connection portion (2651) does not overlap) is placed in the center of the connection portion (22m) of the first wiring pattern (2). ,
Form an electrical component insertion hole (2) so as to penetrate the base material C11) using a mechanical hook RK such as a press. □・Next, semi-cured adhesive (2) is cured with electron beam or heat. A multilayer wiring board (2) shown in FIG. 3 PK is obtained. Although the insertion hole (2) was formed in the process shown in FIG. 3F, the insertion hole (C) may also be formed in advance before the selective etching of the copper foil shown in FIG. This is to prevent the adhesive strength of the connection part (22a) to the base material Ω from decreasing due to the impact when drilling with a press, and the copper foil is applied to the entire surface of the base material (2). If press holes are punched in this state, a decrease in adhesive strength can be avoided.

Then, as shown in Fig. 3GK, insert the lead wire 311 of the electrical component (to) into the insertion hole (2), and
1 and both connecting portions (22m) and (26a) are electrically connected using a conductive material (2). Electrically conductive materials include solder (solder flow, manual soldering, reflow with solder cream, solder coater leveler), gallium alloy (forms in a paste form at the initial working temperature, and its i
Conductive materials such as silver paint, carbon paint, copper paint, etc., which have the property of becoming fully integrated and solidified over time, can be used.

According to the multilayer wiring board (2) having such a configuration, in the connection portion between the lead wire and the wiring pattern in the electrical component insertion hole, the connection portion (26m) of the upper layer wiring pattern (2) is not annular but partially formed in the lower layer. The wiring pattern (two connecting parts (22 m)) is formed in a semicircular shape so that they overlap, so there is no buildup of release liquid when removing the adhesive (to) of the connecting part (2) with the lead wire. In addition, mechanical brushing can be performed sufficiently, and the adhesive (2) can be reliably removed.

As a result, the upper surface of the lower layer connecting portion (221) is clearly exposed and electrical contact with the conductive material (2) is improved.

Also, when attaching conductive material with molten solder dip, the lower layer M! Air in the connecting hook can easily escape, resulting in good soldering and good soldering. At the same time, due to the small area of the upper layer connection (26 m) - the adhesive below (26 m)
), there are fewer gases, moisture, and air bubbles (therefore, the influence of heat stress caused by these on the conductive material is reduced), and the connection part (261) is reduced. When the annular sum is made as shown in the first example, the inner diameter d is determined by taking air escape into account, and the width 1 is also required to be 0.3 or more, so as a result, the connection part (26 m) is To make it smaller, there are 4 sleeping worlds)・Ivy.

However, since the connection portion (26a) formed as in the present invention does not have such limitations, a higher density wiring pattern can be formed.

In addition to the semicircular shape shown in FIGS. 3 and 4, the upper layer connection part (26) may have a width of 111E as shown in FIG. 5, for example.
It may be a K shape or the shape shown in Figure 6, and the mourning is not a ring shape but a lower connection part (22 m) - a metropolitan train that connects Kei.
You can choose any shape.

FIG. 7 shows another embodiment of the invention. In this example,
$7 As shown in FIG. ,
As shown in FIG. 7B, the connection part (22m) of the first wiring pattern (2) and a part of the base material (I'll) in contact with it (
Except #21M), an absolute #1 resin layer (c) is formed by printing. For example, a copper foil (C) with a semi-cured adhesive (C) applied to the entire surface of this base material &1) as shown in Figure CK.
The copper foils (c) are then selectively etched to form a second wiring pattern (2). This time
In forming the wiring pattern (2) of J2, its connection part (26) is connected to the lower layer wiring pattern (26) as shown in Figure 7DK.
2) Be careful not to overlap the connection part (22m).

In other words, the base material υ portion (211
to form. Therefore, both the connecting portions (22 and 26) are formed roughly as shown in the drawing without creating a step.

Next, as shown in Fig. 7EK, both connection parts (22 and (2)
A solder resist layer V0 was formed by printing, and was used as a mask (26M) or a steel IT mask for the solder resist layer (2) and the upper layer wiring pattern (7) on the connection part (22m). Semi-cured adhesive c! 4
1 is dissolved and peeled off using an organic droplet. Next, the lower layer connection (
An electric component insertion hole (through) through which the base material υ is inserted is formed using a 22-inch central sK press or the like. and adhesive (2)
harden. Then 'ljt' as shown in Figure 7 OK
Insert part of the glue IIcIII on the Am product side into the insertion hole (2), and connect the lead wire C (ml) and both connecting parts (22m) and (26m).
a) are electrically connected by a conductive substance.

In the multilayer wiring board 4 having such a configuration, both the connecting portions (22m) and (26m) are formed in the state of the road surface at the connecting portion between the lead wire and the wiring pattern in the electrical component insertion hole. Therefore, as in the case of the embodiment shown in FIG. 3, the adhesive on one of the joints (22&) can be easily and reliably peeled off, and the surface of the joint (22m) can be neatly repaired. , 1. Good electrical connection with the conductive substance (2). Become. Furthermore, when dipping into molten solder, there is no air accumulation and the solder finishes well, and there is little effect of stress on the conductive material 514 during heating (due to residual gas, moisture, and air bubbles in the adhesive). Become.

Figures 8 and 9 show other embodiments of the present invention, in which the diameter of the connection ill (261) of the upper layer grating pattern (2) is smaller than the diameter of the connection * (22 m) of the lower layer. This is a case in which an electric component insertion hole (to) is formed in the center of the internal connection portions (22M) and (26M) which overlap each other and extend to the center of the portion (22M). In this case, no gas leaks from the connecting rod 22 when dipping the molten solder, resulting in a good half-nail connection. , 44 becomes possible.

In addition, the shape of the connection part in Figure 8 is when connecting the electrical component insertion hole (to) to the south (for example, as shown in Figure 10, upper and lower wiring) (connecting turn (2) and It can also be applied to the connection part of the upper layer (215fi) as shown in FIG. Similarly to the above-mentioned FIG. 4, the connecting portion (22M) of the lower layer may have a semicircular shape or the like, overlapping by kW.

FIGS. 12 and 13 show still other embodiments of the present invention. In this example, the parts corresponding to those in FIG. Along with layering, conductive foil pattern-
As shown above, the connection part of the upper layer wiring pattern (2) (
Form 260. In other words, this conductive foil pattern θ does not necessarily have to be connected to other wiring patterns, but rather is a pattern that is separate and independent from the others.

In this way, if there is a dummy conductive foil Ap-νQ1) at the connection part (26m) 7 of the wiring λ and the turn, the electric component
During the molten solder dip for soldering the lead man, it is possible to shield outgassing from the insulating base material (2 pieces), avoiding the influence of degassing on the connection part (261), and using copper foil. The adhesive force of the connection part (26M) is improved.Incidentally, the adhesion force of copper foil decreases when affected by degassing.In addition, in the part of the wiring pattern other than the connection part (26M), the solder resist layer surface is placed on top of it. is applied, so the adhesive force of the pattern 41 does not decrease at that part.This has the same effect in the configurations shown in Figs. 3 to 5 described above. Even if the connecting portion is a pattern with a large area, the same effect can be expected if a conductive foil pattern of 2- is formed below it.

In one example, the resin layer (2) is definitely installed, but the resin layer (c) is definitely omitted and the adhesive (2) is used to insulate the upper and lower wiring patterns @ and (to). It is also Kawa-Noh's idea to use it as an insulating layer.

As described above, according to the present invention, with a simple configuration, the interconnection between the I')-do wire and the wiring (turn) in the electrical component insertion hole is ensured, and it is also possible to form turns with high density wiring. Furthermore, a reliable multilayer wiring board can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional perspective view showing an example of a multilayer wiring board used in the explanation of the present invention, FIG. 2 is a sectional view of its connecting portion, and FIG. Figures 4 to 6 are plan views of the main parts showing examples of the shapes of the connection parts, and Figure 7 is a partially sectional perspective view of the process of the present invention. Work to show another example! ! The perspective views in partial cross section in the order of 4, Figure 8 and Figure 9 are cross sections and plane views of essential parts showing other embodiments of the multilayer wiring board of the present invention.
Figures 1 and 11 are cross-sectional views showing other embodiments of the present invention, and Figures 12 and 13 are cross-sectional views and plan views showing still other embodiments of the present invention. Qυ is the insulating base material, (c) (2) is the conductive foil (turn,
(2) is an electrical component insertion hole, (7) is an electrical component, clll
is a lead edge, and 64 is a conductive material. 4 11” 1J wing

Claims (1)

[Scope of Claims] A conductive foil pattern @1 and a second conductive foil pattern formed by interposing an insulating layer are provided on an insulating base material, and an area of the conductive foil pattern a11 that is not covered with the insulating layer is provided with electricity. A component insertion hole is formed, and the connection part of the second conductive foil pattern partially overlaps the area of the first conductive foil pattern,
Or adjacent. A multilayer wiring board made of