JPS61110494A - Manufacture of through hole 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 [Industrial Application Field] The present invention relates to a method for manufacturing a printed wiring board with through-holes, that is, a through-hole printed circuit board.

[Prior art]

As an example of a method for manufacturing this type of through-hole printed circuit board, as shown in FIG. The surface area that does not need to be covered with solder is further covered with a solder resist 3, and this resist-treated board 4 is immersed in a solder bath to perform a solder dip treatment, and then subjected to a solder leveler step. is better known than before.

In the above procedure, in the first step of the solder leveler, the solder-dipped board [Fig. 3(b)
) and (indicated by 4') are blown with high-temperature air to blow off excess solder on the substrate lands.

However, in the case of the conventional example, the excess solder is not sufficiently blown away in the first step of the solder leveler, and not only does the finished solder film thickness become thick, around 10 μm, but also the film thickness becomes uneven (variations of several μm occur). , which has the problem of making it difficult to mount chip components on the board.

In addition, as shown in Figure 3(b), the solder 5 tends to create a product with the through-holes blocked, which makes it difficult to assemble the mounts and insert the lead wires of the sub-components into the through-holes. This will cause inconveniences such as reduced efficiency.

In addition to the conventional examples described above, a method of obtaining a through-hole printed circuit board by the solder through-hole method is also well known. In this method, as shown in FIG. 4(a), the circuit w4 foil 6 is coated from the surface of the insulating substrate 7 to the inner peripheral surface of the hole, and then the plated solder 8 is coated on the circuit copper foil 6. Therefore, it is possible to avoid inconveniences such as non-uniform solder film thickness and clogging of through holes due to solder as in the conventional example.

However, in this conventional example, since the solder resist 9 is coated on top of the plated solder 8, the substrate 1 is coated with the solder resist 9.
In the solder dipping process performed when attaching a component [the lead wire 11 of the component is shown in FIG. 4(b)] to the 0, plating solder 8 is applied as shown in FIG. 4(b). The molten solder sneaks under the solder resist 9 along the circuit parts, causing problems such as floating, peeling, and waving on the solder resist 9.

[Purpose of the invention]

The present invention has been made in consideration of the above-mentioned problems seen in the conventional example, and has a thin and uniform finished solder film thickness, no clogging of through-holes caused by solder, and a solder resist that is free from solder. The object of the present invention is to provide a method for manufacturing a through-hole printed circuit board that does not float, peel, or wave due to infiltration.

[Structure of the invention]

The method for manufacturing a through-hole printed circuit board of the present invention includes a copper foil processing step for obtaining a copper through-hole board that has been coated with copper foil, and a resist-treated board by covering an area of the copper through-hole board that does not require solder coating with a solder resist. a solder dipping treatment step in which the resist-treated substrate is immersed in a solder bath to perform a solder dip treatment, and a high-temperature air is blown onto the solder-dip-treated substrate pulled out from the solder bath to place the substrate on the substrate. The method is characterized by comprising a solder leveler processing step of blowing away excess solder from the solder leveler-treated board, and a hydro squeegee step of spraying a liquid at the same temperature onto the solder leveler-treated board to blow away excess solder on the board lands and in the through-holes. .

[Example] An example of the method for manufacturing a through-hole printed circuit board of the present invention will be described below with reference to FIGS. 1 and 2.

(1) By a conventionally known process, as shown in FIG. ! A copper through-hole board 14 covered with a circuit copper foil 13 from the surface 12a of the board 12 to the holes 12b.
(copper foil treatment process).

(2) Next, as shown in FIG. 1(b), the area of the surface of the copper through-hole substrate 14 that does not require solder coating is coated with a solder resist 15 to form a resist-treated substrate 16 (resist treatment step).

(3) As shown in FIG. 1C, the resist-treated substrate 16 is immersed in a solder bath 17 to perform a solder dip process (solder dip process).

(4) As shown in FIG. 1(d), air 19 heated to a high temperature is blown onto the solder-dipped board 1B pulled up from the solder tank 17 to blow away excess solder 20 on the board 18. solder leveler treatment process).

(5) For the solder leveler treated board 21, as shown in Fig. 1 (
As shown in e), a liquid 22 heated to a high temperature is sprayed (hydro squeegee process).

As a result, the excess solder 20 remaining on the substrate lands and in the through-holes is melted and blown away, and as shown in FIG. A printed circuit board 23 is finished.

In addition, at the time of passing through the solder leveler treatment, as shown in FIG.
), even if the through-holes of the board 21 are clogged with solder 20, the solder 20 clogging the through-holes is blown away by the spraying of the high-temperature liquid 22 in the hydro-squeegee process. As shown in FIG. 2(b), a through-hole printed circuit board 23 with no through-hole clogging is obtained.

〔Effect of the invention〕

Since the method for manufacturing a through-hole printed circuit board of the present invention has the above-described configuration, the following excellent effects can be obtained.

(b) Excess solder remaining on the board land even after solder leveler processing is blown away by the hydro squeegee process, making it possible to make the finished solder film extremely thin and uniform, making it possible to easily attach chip components to the board. Not only can it be easily installed, but it can also contribute to improving the efficiency of assembly work.

(b) Even if the through-holes are clogged with solder after the solder leveler treatment, the solder clogging the through-holes can be reliably blown away by the hydro squeegee process, so the solder can be mounted. It is possible to avoid situations such as not being able to insert lead wires of electronic components into through-holes, and it is possible to more efficiently mount components onto the board.

(c) The copper through-hole board that has been coated with copper foil and has not yet been coated with solder is manufactured by coating solder resist on the surface area that does not require solder coating, so the circuit under the solder resist forms this circuit. Since the copper foil is directly covered with the solder resist, the solder does not get under the solder resist during the solder dip treatment unlike in the case of boards obtained by the solder through-hole method. Occurrence can be avoided.

[Brief explanation of the drawing]

FIGS. 1(a) to (f) are process explanatory diagrams showing one embodiment of the present invention, FIGS. 2(a) and (b) are explanatory diagrams showing the effect of eliminating clogging of through holes by the hydro squeegee process, FIGS. 3(a) and 3(b) are explanatory views showing the problems of the conventional example, and FIGS. 4(a) and 4(b) are explanatory views showing the problems of another conventional example. 12 is an insulating substrate, 13 is a circuit copper foil, 14 is a copper through-hole substrate, 15 is a solder resist, 16 is a resist-treated substrate, 17 is a solder bath, 18 is a solder dip-treated substrate,
19 is high-temperature air, 2o is solder, 21 is a board treated with a solder leveler, 22 is a high-temperature liquid, and 23 is a through-hole purine 1-aE board.

Claims (1)

[Claims] 1. A copper foil treatment step for obtaining a copper foil-coated copper through-hole board; a resist treatment step for obtaining a resist-treated board by coating solder resist on the area of the copper through-hole board that does not require solder coating; and the resist-treated board. a solder dip treatment step in which the solder is immersed in a solder bath to perform a solder dip treatment; a solder leveler treatment step in which high temperature air is blown onto the solder dip-treated board pulled up from the solder bath to blow away excess solder on the board; A method for manufacturing a through-hole printed circuit board, comprising a hydro squeegee step of spraying a high-temperature liquid onto a leveler-treated board to melt and blow off excess solder on the board lands and in the through-holes.