JPS60176298A - Method of producing multilayer printed 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 (Technical Field) The present invention relates to a method for manufacturing a multilayer printed wiring board, and particularly to a method for manufacturing an inner layer of a multilayer printed wiring board.

In recent years, as electronic components such as ICs and LSIs mounted on printed wiring boards have become faster and more dense, the supply of power consumed by these electronic components has become a problem. For this reason, there is a trend to gradually increase the thickness of copper foil used for the inner conductor layer of multilayer printed wiring boards to improve power supply. That is, in general, copper foil with a thickness of 35 to 70 μm was used for the power supply layer and the ground air layer as inner conductor layers, but copper foil with a thickness of 150 to 300 μm or more is used. By doing so, we are trying to improve the power supply.

(Prior Art) Figures 1A to 1-- show the manufacturing process of a multilayer printed wiring board using a thick inner conductor layer by a conventional method.

FIG. 1(A) is a sectional view of a double-sided gold maple-covered insulating board in which thick gold maple foils 2a and 2b are adhered to an insulating base material 1.

Here, the gold maple foils 2a and 2b are, for example, copper foils with a thickness of 150 μm or more.

Next, photosensitive resin layers 3a, 3b are applied on the gold foils 2a, 2b (for example, Riston Dry Film "1220" manufactured by Dapon Co., Ltd.).
)'t-deposition and photomask 4a.

4b (Fig. 1 (B)), and the etching resist film 5a, 5b is formed by removing the etching resist film 5a and 5b using a solvent such as chlorocene (Fig. 1 (B)).
CJ).

Next, the portions of the maple foils 2a and 2b that are not covered with the etching resist coatings 5a and 5b are removed by etching using a second chloride solution. b' is dissolved and removed using a solvent such as methylene chloride to complete circuit formation on the inner layer plate 6 (FIG. 1 (uniform)).

Next, inner layer &6 and outer conductor layer 8a, 8be Gripreg 7a
, 7b and 7c, 7d? ! -It should be placed through m1 figure 0
1), and then thermocompression bonded using a hot press to form a multilayer substrate 9 (FIG. 1(G)).

Next, through holes IO are made in the multilayer substrate 9 (FIG. 1 (c)), and the outer conductor layers 8a and 8b and the inner conductor layer 11a are formed.

Through-hole cutout 11- for electrically connecting between tib
Furthermore, as shown in FIG. 1(i), a photosensitive resin*3c, 3 is applied to the surface of the through-hole plating 120 formed on the outer non-conductor layer ga, 8b.
dt-layer formation and photomask4. The unentangled portions are dissolved and removed using a solvent such as chlorocene to form etching resist films 5c and 5d (Fig. 1 (6)). .

Next, the portions not covered by the etching resist coatings 5c and 5d formed on the through-hole holes 12 were removed by etching with cupric chloride, etc., as shown in FIG.
Further, the etching resist layers 5c and 5d are removed with a solvent such as methylene chloride to obtain a multilayer printed wiring (No. 11).

However, the above-mentioned conventional method had the following three major drawbacks when thick gold paulownia foil was used for the inner conductor layer. In other words, (a) the undercap caused by etching becomes larger;
Circuit formation accuracy deteriorates, etching residue and over-etching are likely to occur, resulting in insulation deterioration or power supply failure. Table 1 shows an example of the accuracy of circuit formation using the conventional method.

Table 1 (b) Since the gap between the insulating base material of the inner layer board and the inner layer circuit pattern is large, the stepped portion is not filled with resin during lamination, resulting in lamination voids.

←9 As in (b), the large step difference deteriorates the flatness of the outer conductor layer, causing poor adhesion of the etching resist film and non-light blurring.

(Objective of the Invention) An object of the present invention is to provide a method for manufacturing a multilayer printed wiring board that eliminates such conventional drawbacks.

(Structure of the Invention) According to the present invention, multilayer printing allows for good power supply, high circuit formation accuracy, no lamination voids, good flatness of the outer conductor layer, and high precision pattern formation. The manufacturing method of a wiring board includes the step of etching a conductor layer at a desired position, and applying insulation 8M resin to the etched surface of the etched conductor layer.
and a conductor layer 2 on which the disconnected layer is formed.
A step of thermo-compression bonding the inner layer plate through one leg to form an inner layer 116&k, a step of applying an etching resist to a desired position on the surface of the inner layer plate, and a step of applying an etching resist to the etched surface of the inner layer plate. A process of forming a disconnected layer by placing the above-mentioned insulating layer on the inner layer, and a process of forming a multilayer structure by placing one or more sheets of the insulating layer on the inner layer, and bonding the outer layer conductor 1- by thermocompression via a prepreg. a step of forming through holes on the multi-I substrate, a step of applying through hole plating to the multi-layer substrate on which the through holes are formed, and a step of forming a desired outer layer of the multi-layer substrate with the through hole plating A method for manufacturing a multilayer printed wiring board is obtained, which is characterized by comprising the steps of etching away the positions and forming an outer layer circuit.

(Example) Hereinafter, examples of the present invention will be described in Fig. 2 (N~()) and Fig. 3 (
5) to (F), will be explained using FIG. 2 ((J-(U)).

FIG. 2 (At) and FIG. 3 (A) are one-part diagrams of the metal foils 2a and 2b.

For example, copper foil with a thickness of 150 μm or more is used as the gold S4 foils 2a and 2b.

Next, photosensitive resin layers 3a and 3b are placed on the maple foils 2a and 2b.

3c, 3d (for example, Riston dry film manufactured by Dapon Co., Ltd. $1220) k is deposited, and photomask 4a is formed.
, 4b, 4c, and 4de (Fig. 2 (B)
), FIG. 3 (binding), the etching resist film 5a is formed by dissolving and removing the exposed portion using a solvent such as chlorocene,
5b, 5c, and 5di are formed (Fig. 2(C), 8
Figure 3 (C)). At this time, the photomasks 4a and 4d are made so that the entire surface thereof is light-transmissive, and the entire surface of the photosensitive resin is coated with the etching resist.
5a, 5dt-metal foil 2a.

It is formed on the entire surface of one side of 2b.

Next, from one side of the gold 8 foils 2a, 2b, the portions not covered by the etching resist coatings 5a, 5b, 5c, 5d are etched using cupric chloride or the like, so that the etching depth is at least that of the metal foils 2a, 2b. Etch the thickness to more than 1/2 of the thickness (Fig. 2 (U).

Figure 3 (b).

Next, apply etching resist %sa, sb'J? and 5c
, using a solvent such as 5di methylene chloride (second
Figure (Kado, Figure 3 (Oi).

Next, insulating resin layers 14a, 14b are formed on the etched side of the pot @ Tomari'l a, 2b by screen printing, roll coating, etc., and one side resin coated metal foil 15a, 15b'e shadow is formed. (Figure 2 ψ゛).

Figure 3 (F)).

Next, the single-sided resin-coated metal foils 15a and 15b are placed through the prepreg 7 so that the insulating resin layers t4a and 14b face the side of the first leg 7 (FIG. 2). Obtain (Figure 2 u10 then inner layer &
photosensitive resin layer 3e on the surface of 16;

3F (for example, Riston Dry Film manufactured by Chipon Co., Ltd.)
1220) t”M deposition is formed, and photomasks 4e, 4
f (Fig. 2 (I)), and the immature optical part is dissolved and removed using a solvent such as chlorocene to form etching resist films 5e and 5fi (Fig. 2 (I)).
J)).

Next, the portions of the inner layer plate 16 that are not torn in the etching resist coatings 5e and 5f are etched using an etching solution such as a dichlorochloride solution to form a through hole 5i7a.

17b and 17c are formed (FIG. 2 (5)).

Next, the insulating resin layers 14a, 14bfc are formed on the surface of the inner layer plate 16 on which the shells 17a and 17ci have been formed by screen printing, roll coating, etc., and the inside of the insulating resin coat 1
- formation of an illumination (see Figure 2)).

Next, the insulating resin cord inner layer plate 18 and the outer j-exclusive l casting 8
a, 8bk Grig Reg 7.7.
N+) and thermocompression bonding to form a multilayer substrate 1'l (FIG. 2<(J)).

Next, open a through hole (l) in the multilayer group &19 (Fig. 2 (
P)), 1 m 8 a of outer layer conductor in throughhole lO.

8b and the end face of the conductor portion of the insulating resin cord inner layer plate 18 are electrically connected through-hole plating 12t''m (FIG. 2(Q)), and further on the through-hole plating 12 applied on the outer conductor layers 8a and 9b. After forming a photosensitive resin layer of 3g and 3h1kwL on the film, it was made to be unlighted through a photomask of 4g and 4he (Fig. 2 (koji)), and the unlighted part was completely washed with a solvent such as chlorocene.
Etching resist film removed 5g, 5 hours? <Formation (Fig. 2 (S)).

Next, the portions of the through-hole plating 12 that are not covered by the etching resist films 5g and 5h are removed by etching using a cupric chloride solution or the like.

Furthermore, it was removed using a solvent such as Sotengresist IL1% 5g and 5h'i methylene chloride, and multilayer printed wiring and
23 (Figure 2 (IJ)).

(Effects) As described above, in the method of the present invention, since the thick gold maple foil is etched in two steps from one side, undercuts are reduced and circuit formation accuracy is improved. Table 2 shows an example of the accuracy of forming the inner layer according to the method of the present invention.

Table 2 Also, since the outer part of the through-hole that passes through the etched part of the thick gold maple foil is filled with insulating resin, the occurrence of detection is small, there is no lamination hoid, and the outer conductor layer is flat. Since the characteristics do not change, it has become possible to form outer layer circuits at a high level of quality.

In addition, in this example, a four-layer multilayer printed wiring board using one insulating resin coated inner layer board was explained, but two or more insulating resin coated inner layer boards were formed using Rurui or a normal construction method. Of course, there is no problem even if the inner layer plates are used in combination.

[Brief explanation of drawings]

FIG. 1S-1 is a cross-sectional view showing the manufacturing process of a multilayer printed wiring board using a conventional method. Figure 2 (5) - (F), Figure 3 (N - (0, Figure 2 (q
- (U) are cross-sectional views showing the manufacturing process of a multilayer printed wiring board by the method of the present invention. ■...Insulating base material, 2a, 2b...Golden maple foil, 3a-3h...Photosensitive resin layer, 4a-4h
...Photomask, 5a to 5h...Etching resist cover 1 return, 6゜16...Inner layer plate, 7a to 7d, 7...Brig leg, 8a , 3
b...Outer conductor layer, 9.19...Multilayer substrate, lO...Through hole % lla, 1
lb------Inner lWI conductor noso, 12...
Through hole, @, 13, 23...Multilayer printed wiring board, 14a, 14b...Insulating resin layer, 15a
, 15b... One side resin coated gold maple foil, 17a. 17b, 17c... Penetration part, 18...
Insulating resin coated inner layer board. Ho / Illustrated lacquer / Taku / Simple analysis 2 Illustrated calculation 2 Country

Claims (1)

[Claims] A step of selectively etching a conductor layer from 10,000 sides, and forming an insulator on the etched surface of the etched conductor layer to form an insulating layer. a step of forming a first inner layer plate by crimping two conductive layers with the insulating layer formed thereon via a preglypreg; and applying machining and sautéing to a desired position on the surface of the first inner layer plate. a step of forming an insulator on the surface of the etched first inner layer plate, forming an insulating layer, and completely forming the second inner layer plate; 3U2 1 or more second inner layer plates t are placed inside j-,
A step of forming a multilayered substrate by crimping an outer conductor layer via a Gripreg, a step of forming through holes in the multilayered substrate, and a step of applying through hole plating to the multilayered substrate with the through holes formed therein. A method for manufacturing a multilayer printed wiring board, comprising the step of removing desired positions of the outer layer of the multilayer substrate subjected to the through-hole plating by ultraviolet etching to form an outer layer circuit.