JPS6236899A - Manufacturing method for single-sided through-hole wiring 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] (Industrial application field) The present invention relates to a method for manufacturing a single-sided through-hole wiring board.

(Prior art) Single-sided printed wiring boards, which are mainly used in consumer electronic equipment such as radios, TVs, and VTRs, are made by using one-sided copper-clad plating board'f: and etching the copper foil (in two places). In addition to forming the pattern of the shank, the parts lead wire insertion hole (through hole) for mounting the parts in one piece and the external shape are processed on the bunching.On the wiring board created in this way,
An example with electronic components attached is shown in Figure 2.

In FIG. 2, 21 is an insulating layer, 22 is a circuit pattern, 2
5 is a bat, 24 is a through hole, 25 is an electronic component, 2
6 is solder. The electronic component 25 is attached by passing its lead edge through a through hole 24 on the component surface of the wiring board and soldering the entire lead wire to the butt 25 on the solder dip surface.

In this single-sided printed wiring board, since the electronic component 25 is fixed by soldering only at the lead wire 23 portion, there remains a problem in soldering reliability. A single-sided through-hole wiring board as shown in FIG. 5 has excellent soldering reliability.

The single-sided through-hole wiring board has copper plating applied to the inner wall of the hole (through-hole) 34, and the smudge component 35 is placed on the other side.
By applying the solder 54 to the lead wire, not only the pad 63 but also the hole is filled with the solder 34, and the lead wire is firmly attached.

Therefore, soldering reliability is further improved, which is very desirable in terms of quality assurance. In FIG. 3, 51 is an insulating layer and 52 circuit patterns.

Particularly when used under conditions of severe vibration, the effect of a single-sided through-hole wiring board is particularly evident.

For example, it is widely used in electronic devices installed in automobiles.

This single-sided through-hole wiring board is usually manufactured by the method shown in FIG.

That is, when the single WJ copper-clad laminate 41 (A) is subjected to the surface gold catalyst treatment without the copper foil 42, electroless plating is deposited.
Print resist 45 to prevent the catalyst from sticking (B)
. Hole 44 drilling (C), catalyst 45 treatment (DJ, resist 4
5 Peeling (E), electroless plating, electrolytic plating (primary) 46
(Fl, plating resist 47 printing (G), vl deplating (secondary) 48, soldering 49 (Hl, plating resist 47 peeling (■), etching (J), solder resist 5G
It is manufactured in the printing (K) process. Solder plating 49 (
Instead of H), the circuit may be formed by a tenting method or a hydraulic method.

(Problem to be solved by the invention) However, this method starts from a single-sided copper-clad laminate, and since there is copper foil on only one side and no copper foil on the other side, electroless steel plating is not possible. When carrying out the catalyst treatment (D)' in the holes, which is the pretreatment process of The film is removed after the catalyst treatment to prevent the catalyst from adhering to the surface of the insulating plate. Therefore, it is safe to use a process to prevent the catalyst from adhering to the surface of the one-sided insulating plate without the TN foil, and for this reason, the number of processes is greater than that of the manufacturing process of the art dealer through-hole wiring board.

The present invention provides a method for manufacturing a single-sided through-hole wiring board that shortens the manufacturing process and facilitates the formation of high-density wiring patterns.

(Means for solving problems) The present invention will be explained clearly with reference to FIG.

Figure 1 (5) shows a single-sided copper-clad laminate, with copper foil 1
1. It is formed from an insulating layer such as a catalyst-containing laminate/i#12 and a non-catalytic insulating layer 15 (57iil). In the catalyst-containing Plij layer, a catalyst is contained in the insulating layer, and copper is deposited without the need for catalyst treatment during electroless plating.

In other words, the catalyst is uniformly distributed on the surface of the inner wall of the hole drilled in the catalyst-containing insulating plate, so if the hole is immersed in an electroless copper plating bath, electroless copper will be deposited on the inner wall surface of the hole. .

However, general N! Since the third edge layer (non-catalytic insulating layer) does not contain a catalyst, no copper is deposited in that layer.

As a catalyst, metals belonging to Groups 1 and 1B of the periodic table of elements, such as nickel, gold, silver, platinum,
Palladium, rhodium, copper iridium, etc., or their oxides, chlorides, bromides, fluorides, ethyl acetate,
Examples include fluoroborates, nitrates, sulfates, and acetates. Particularly useful are palladium, gold, platinum, copper, palladium chloride, gold chloride, platinum chloride, copper oxide or combinations thereof containing tinn chloride. These catalysts are adsorbed on an Al20s-8iCh carrier, mixed with epoxy resin and dispersed in a thermosetting resin face, and this is impregnated into a base material such as glass cloth or paper and dried. Make prepreg containing catalyst.

Also, a catalyst-free prepreg is made without mixing a catalyst. Manufacture a single-sided copper-clad laminate by stacking the required number of catalyst-containing prepreg sheets on one side, laminating the required number of catalyst-free prepreg sheets on the other side, laminating all the copper foil on the other side, and integrating the whole under heat and pressure. do.

A single-sided copper-clad laminate is used, which is composed of a laminate mixed with an electroless plating catalyst, a laminate layer of a predetermined thickness on one side that is not mixed with an electroless plating catalyst, and a copper foil on the other side. (4) First, a resist pattern for etching resistance is formed by printing, and a rainbow@foil pattern 14 is formed on the etching (B). Holes 15 are made at the required locations (C), and 16 permanent nosists are injected completely on the part of the copper foil pattern other than the butt (the part to be soldered) (I)). The permanent nozzle ink is a plating-resistant ink that does not deposit electroless copper even when immersed in an electroless plating bath. Moreover, the permanent resist ink does not completely contaminate the plating solution due to dissolution even if it is immersed in the electroless plating solution for a long time.

When a wiring board printed with permanent resist ink is immersed in a total electroless plating bath, copper 17 is deposited only on the copper foil and the surface of the catalyst-containing insulation (inner wall surface of the hole), and other permanent resist inks are removed. No copper is deposited on the surface or the surface of the insulating layer that does not contain a catalyst (non-catalyst insulating layer). Therefore, it is possible to obtain a single-sided through-hole distribution plate with copper plating 17 applied only to the required portions.

The cases of etching (B) and drilling (Qffl plating resist formation (r)) have been shown above, but etching (B),
Plating resist formation (1')), drilling (C), or drilling (C1), etching (B), plating resist formation (
L)) copper can also be used.

(Effects of the Invention) In the method of the present invention, a single-sided copper-clad laminate consisting of a copper foil, a catalyst-containing layer, and a non-catalyst layer is used, and
Since electroless copper plating is entirely deposited only on the required inner wall portion of the hole, a single-sided through-hole wiring board can be manufactured with a simple process.

Further, by changing the thickness Tl of the non-catalytic insulating layer, the height Tl (corresponding to the thickness of the catalyst-containing layer) at which electroless plated copper is deposited on the inner wall of the hole can be arbitrarily selected. Copper precipitation height T
It is completely impossible to vary l arbitrarily using conventional methods. In the conventional method, the inside of the hole is plated with copper by electroplating, but the copper plating is also deposited at the hole exit on the part surface (the side without the butterflies) and rises to the hole exit. Adding to this effect, in the case of holes that are very close to each other, the solder protrudes from the hole due to solder frying, and a blister is generated due to the neighboring hole and the half hole.

In the present invention, even if the holes are close together, there is little solder buildup, so no bridging occurs due to solder.

The height Tl of the plating applied to the inner wall of the hole is generally &X 10
0%==20-50% is suitable.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the method of the present invention, FIGS. 2 and 5 are sectional views of a wiring board, and FIG. 4 is a sectional view showing the conventional method. Explanation of symbols 11, copper foil 12, catalyst-containing insulation No. 15, non-catalytic insulation layer 14, pattern 15, hole 16, permanent resist 17, deposited steel

Claims (1)

[Claims] 1. Etching and drilling a single-sided copper-clad laminate consisting of a laminate mixed with an electroless plating catalyst, a laminate layer of a predetermined thickness that does not contain the electroless plating catalyst on one side, and copper foil on the other side. , one side characterized by performing electroless plating after forming a plating resist, or performing etching, forming a plating resist, and drilling, or performing drilling, etching, and forming a plating resist. A method for manufacturing through-hole wiring boards.