JPS6236896A - 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 devices such as radios, TVs, and VTRs, use a single-sided copper-clad laminate, and the copper foil is etched to form the desired pattern. At the same time, the parts lead insertion holes (through-holes) for mounting parts and the entire external shape are created by punching. FIG. 2 shows an example in which electronic components are attached to a wiring board prepared in this manner.

In FIG. 2, 21 is an insulating layer, 22 is a circuit pattern, 2
3 is a bat, 24 is a through hole, 25 is an electronic component, 2
6 is solder. For the electronic component 25, pass the lead wire through the through hole 24 on the component surface of the wiring board,
Attach the butt 25 on the dip surface and the lead wire to the semicircular part.

In this single-sided print spinning vine, since the electronic component 25 is fixed to the lead M' by soldering only the butt 25 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 a copper plate on the inner wall of the hole (through-hole) 34, which allows electronic components 3 to be attached.
5, the lead wire is attached to the bat 65 by soldering 34.
Not only that, but also the solder 34 is filled in the hole and firmly attached.

Therefore, soldering reliability is further improved, which is very desirable in terms of quality assurance. In FIG. 5, 51 is a PR layer and 62 is a circuit pattern.

Particularly when the camera is used under intense shooting conditions, the effect of the single-sided through-hole wiring board becomes more apparent.

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

When manufacturing this single-sided through-hole wiring board by a fully additive method, the method shown in FIGS. 4 and 5 is usually used.
will be built.

In Figure 4, if adhesive 41 is used and JfI treated 42 is used, but if a plane circuit is not formed and the surface to which no adhesive is applied is treated with a catalyst, electroplating will precipitate and the catalyst will not adhere. Print a resist 43 for printing (B). After that, add 44 (C), catalyst 45 treatment (D), resist 4
3 stripping # (E), plating resist 46 formed (F), no 11
Perform deplating 47 (E) to manufacture a single-sided through-hole wiring board.

In the case of FIG. 5, a catalyst-containing laminate plate 52 with a catalyst-containing adhesive 51 is used (A). In this case as well, the entire resist 53 is printed to prevent electroless plating from depositing on the surface where no planar circuit is formed and no adhesive is attached (Bl. After that, the holes 54 are drilled (C), and the plating resist 55 is formed fD )
, electroless plating 56 (E), and resist 53 peeling fF) to produce a single-sided through-hole wiring board.

(The problem to be solved by the invention) However, in the methods shown in FIGS. 4 and 5, resist 45 is used to prevent the catalyst from adhering to the substrate during catalyst treatment, and electroless plating is applied to the substrate. A step of forming a resist 55 to prevent precipitation is required, which increases the number of steps.

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 a high-density wiring pattern.

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

FIG. 1(4) shows an adhesive laminated plate which is an insulating substrate, and is made of 2N of catalyst-containing insulation 11 and non-catalytic insulation 1-12.

In the catalyst-containing insulating layer, a catalyst is contained in the insulating layer, and there is no need for catalyst treatment during electroless plating, and copper is deposited.

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

However, since a general insulating layer (non-catalytic insulating layer) does not contain a catalyst, no copper is deposited in that layer.

As a catalyst, metals included in Group Ⅰ and Group 1B of the Periodic Table of Elements, such as nickel, gold, silver, platinum,
Examples include palladium, rhodium, copper, iridium, etc., or their oxides, chlorides, bromides, fluorides, ethyl acetates, fluoroborates, nitric acid groups, salt salts, acetates, and the like. Particularly useful are palladium, gold, platinum, copper, palladium chloride, gold chloride, platinum chloride, oxidized steel or their combinations with stannous chloride. These catalysts are adsorbed onto an A71203 8t02 carrier, mixed with epoxy resin, dispersed in thermosetting resin varnish, impregnated into a substrate such as glass cloth or paper, and dried. Make prepreg containing catalyst.

Also, prepreg without catalyst can be made without mixing the catalyst at all. Required number of sheets of prepreg with catalyst Lay the required number of sheets of prepreg without catalyst on one side of the stack, heat and pressurize the whole to make a laminate, and apply catalyst-containing adhesive on the opposite side of the prepreg without catalyst. form a layer.

Like this, no t'! A catalyst-containing insulating layer 11 consisting of a laminate containing an N plating catalyst and an adhesive layer containing an electroless plating catalyst, and a catalyst-free insulating layer 12 such as a laminate of a predetermined thickness that does not contain a S electrolytic plating catalyst. Using the entire edge substrate (N), holes 15 are bored at predetermined locations, and a plating resist 14, which is a permanent resist, is formed at locations other than the portions that will become circuit patterns.

The permanent resist ink is a plating-resistant ink that does not deposit electroless copper on the surface even when immersed in an electroless plating bath. Furthermore, the permanent resist ink does not contaminate the plating solution due to dissolution even if it is immersed in the electroless plating solution for a long time.

When the wiring board marked with the permanent resist ink 1j is immersed in an electroless plating bath, copper 15 is deposited only on the surface of the catalyst-containing insulating layer (the inner wall surface of the hole), and the other permanent resist ink surfaces and the catalyst are immersed in the electroless plating bath. Copper does not precipitate on the surface of the insulating layer that does not contain (non-catalytic insulating layer). Therefore, the copper plating 17 is applied only to the required portions, and can be applied to the single-sided through-hole wiring board.

Above, drilling (after BJ plating resist formation fQO field @ fully shown, after plating resist formation (C), drilling fB)
, you may do so. Further, the adhesive /i# may not necessarily be used.

(Effects of the Invention) In the method of the present invention, the entire insulating substrate consisting of a catalyst-containing layer and a non-catalyst layer is used, and piezothermal electrolytic copper plating is deposited only on the inner wall of the required hole, so the process is simple. It is possible to manufacture single-sided through-hole wiring boards using this method.

Further, by changing the thickness T1 of the non-catalytic insulating layer, the depth T2 (corresponding to the thickness of the catalyst-containing layer) of the deposited electroless plating layer on the inner wall of the hole can be arbitrarily selected. Copper precipitation height T2
It is completely impossible with conventional methods to change the value arbitrarily. In the conventional method, the component side (the side without a pattern)
The copper plating also pulls out from the hole exit and rises to the hole exit. In addition to this effect, in the case of holes that are very close together,
Due to solder frying, the solder protrudes from the hole and generates blister due to the solder and the adjacent hole.

In the present invention, even if the holes are close to each other, there are few uphill steps, so no bridging occurs due to solder.

The height T2 of the plating on the inner wall of the hole is generally -Yl-x
1oo%=20-50% is appropriate.

T　I+　T　2

[Brief explanation of drawings]

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 FIGS. 4 and 5 are sectional views showing the conventional method. Explanation of symbols 11, insulating layer with catalyst 12, insulating layer without catalyst private university 14, plating resist 15, deposited copper V, Peng 1- Fig. 5

Claims (1)

[Claims] 1. After drilling and forming a plating resist on an insulating substrate consisting of an insulating layer containing an electroless plating catalyst and an insulating layer not containing an electroless plating catalyst formed on one surface thereof, or after forming a plating resist and drilling, A method for manufacturing a single-sided through-hole wiring board characterized by performing electroless plating.