JPS6332995A - Manufacturing method of printed wiring board - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a method for forming a circuit pattern on a printed wiring board, and particularly relates to a method for selectively forming a coating film on a metal foil such as copper using an electrodeposition coating method. The present invention relates to a method for forming a desired circuit pattern using the etching resist film as an etching resist film.

C. Prior Art] Printed wiring boards are produced by forming a resist film on a metal foil, such as copper foil, on an insulating substrate, exposing and developing a desired pattern to form a resist film, and then etching using this as a mask. The desired circuit pattern is obtained.

An example of this conventional general pattern forming method for printed wiring boards is shown below.

FIG. 3 shows a part of a printed wiring board produced by this conventional manufacturing method, in which fil is an insulating base made of a laminated board such as glass epoxy, and (2) is an insulating base provided on this insulating base (11). The circuit pattern (3) is connected to the pattern (2) by a land provided at the edge of the component mounting hole or through hole. (4) is a through hole in the center of this land (3). , FIG. 4 shows an enlarged cross-sectional view taken along line A-A in FIG.
2) a solder plating provided thereon. FIG. 5 shows a conventional manufacturing process for the printed wiring board shown in FIG.

In the figure, (6) is an insulating base material (1) with a through hole drilled.
Panel steel plating applied to the surface and edges of the through hole 5
(7) is a resist film formed on this panel steel plating (6), exposed and developed in a desired pattern, and (8) is a resist film applied to the surface of panel steel plating (6) other than this resist tl*t7+. Patterned copper plating.

Incidentally, this manufacturing method is referred to as a manufacturing process for solder-plated through-hole printed wiring boards, and is adopted as a manufacturing method for high-density through-hole wiring boards.

Next, each step of the conventional method for forming a circuit pattern on a printed wiring board will be explained with reference to FIG.

First, as shown in Figure 5-A, a thin v
After drilling a small through hole (for example, 0.9 m in diameter) in the copper-clad laminate covered with A foil, electroless copper plating is followed by panel copper plating (electroplating) (6), and through hole (4) is applied. 0 Next, as shown in Section 5-Shikoku, the plating resist film (7) is formed into the desired circuit using a dry film or a photoresist method using a liquid photosensitive liquid, or a screen printing method using a liquid acid-resistant alkali. It is applied on the panel steel plating film (6) in a pattern opposite to the pattern.

Then, as shown in Figure 5-C, a plating resist film (
Patterned copper plating (
8) treatment, and further perform solder plating (5) treatment thereon.

Furthermore, as shown in Figure 5-2, the used and wrinkly resist film (7) is removed with a special peeling liquid, and the
A pattern is formed as shown in Figure E. At this time, unnecessary copper (WA foil and panel steel plating III) is etched with a special etching solution, and each circuit pattern is formed independently.

[Problems to be solved by the invention] In the conventional pattern forming method for solder-plated through-hole printed wiring boards shown in FIG. 5, it is difficult to control the solder plating solution and the etching solution used is limited . (A particularly expensive etching solution is used.) (2) The permissible range of solder plating conditions is narrow, which is disadvantageous for forming small-diameter through holes (aspect ratio of 5 or more). (2) There are many post-processes after pattern formation such as solder cleaning and fusing, and the melted solder flows during fusing, causing various problems. ■If a solder plating film is not required, a solder stripping process is required. ■Solder plating solutions are also disadvantageous in terms of pollution. There are other problems.

This invention was made to solve the above-mentioned problems, and since no solder plating is used in etching resist, it is advantageous in terms of pollution, eliminates the need for a soldering process, and is particularly effective in forming high-density patterns. ■ Formation of through holes in small lands ■ The aim is to obtain a manufacturing method that easily enables the formation of fine patterns without chipping or disconnection because the etching resist (electrodeposition coating) is completely filled into copper defects. do.

[Means for solving problems]

The method for manufacturing a printed wiring board according to the present invention is to apply a part or the entire surface of a metal-clad laminated insulating board for printed wiring, including the inside of the through-hole of a printed wiring board having through holes such as through holes, to an electrodeposition coating tank. It is manufactured using a process in which a cationic resist film is deposited by immersion in a contained water-soluble resin for electrodeposition coating by direct current electrolysis.

[Effect]

In the method for manufacturing a printed wiring board according to the present invention, panel steel plating is applied to the surface of a metal foil laminate made of copper or the like in a water-soluble resin stored in an electrolytic bath, and then a plating resist film is formed in a reverse pattern. The work plate is immersed and a resin film is deposited in the desired pattern using DC electrolysis. After photo-curing or drying, only the plating resist film is coated with a special peeling liquid (N
a Remove with an alkaline aqueous solution such as OIf). The deposited cationic resin film is then used as an etching resist film and is etched with an etching solution (alkaline etchant used for solder resist) to form a fine pattern.After etching, the cationic resin film is removed using a special peeling solution. Remove with dilute hydrochloric acid, etc. As a result, printed wiring boards with fine patterns and small-diameter through holes without chipping or disconnection can be formed even when using solder plating, which requires difficult liquid management and plating conditions, requires expensive etching liquid, and is disadvantageous in terms of pollution.

Embodiment C] FIG. 1 is a cross-sectional view showing each step of a method for manufacturing a printed wiring board according to an embodiment of the present invention, and FIG. 1-A and FIG. This is the same process as shown in the figure). Also +11~(4).

(6) to (8) are the same as those explained in the conventional example. In Figure Iha, α・ is the plating resist on the surface of the panel copper plating (6) (? is the electrodeposited coating film attached to the surface of the patterned copper plating (8) applied to areas other than 1),
Dedicated stripping solution for plating resist (7) film (11aOHa
It is a cationic electrodeposited film that is resistant to alkaline aqueous solutions such as g) and soluble in acids. In addition, Fig. 2 shows a coating tank in which this electrodeposition coating is performed, and in the figure, QD is the electrodeposition coating tank, @ is an air blowing pipe for agitation that stirs the contained water-soluble cationic resin material made into an electrodeposition coating, and α is the shaded area, and O5 is the work plate housed in the coating tank 0υ.

Next, a method of manufacturing a printed wiring board according to an embodiment of the present invention will be explained in order. First, figure! - After drilling a through hole in a copper-clad laminate made of an insulating base material (1) covered with thin copper foil, panel copper plating (electroplating) (6) is performed following electroless copper plating as shown in (A). to form a through hole (4).

Next, as shown in FIG. 1, a plating resist (7) film is applied on the panel copper plating (6) film in a pattern opposite to the desired circuit pattern as in the conventional example. Next, the alkali-resistant cationic electrodeposition paint is immersed in water-soluble cationic resin (1 m (hereinafter referred to as paint liquid)) shown in Fig. 2, and a voltage of about 200V is applied between the work plate a9 and the cathode (2). When a DC voltage of
Electrodeposition begins on the patterned copper plating (8) as shown in FIG. Thereafter, the work plate α is pulled up and photocured or dried to obtain an electrodeposition coating OI that becomes an etching resist.Next, as shown in Figure 1-2, the used plating resist l-
71 film was removed using a special # synergic solution (alkaline aqueous solution such as NaOHag), and then the excess copper foil and panel copper plating ( 8) When the film is etched, copper remains in the pattern formed by the electrocoating liquid Ill Ql, and independent circuit patterns are generated. Since the used electrodeposition coating α0 is dissolved in acid, it is removed with a special IJM agent (hydrochloric acid AG, etc.) and placed on the surface of the insulating base material fi+ and through holes (4) as shown in Figure 1-. After the circuit pattern is generated, the process proceeds to processes such as solder resist printing as in the conventional method, and the printed wiring board is completed.

In addition, when applying the manufacturing method according to this example to a method for forming an inner layer pattern of an inner layer board of a multilayer printed wiring board, it is necessary to use an electrodeposition paint that has heat resistance and alkali resistance in addition to the above explanation. For example, after forming the circuit pattern (2) as shown in FIG. 1-E, it is possible to directly proceed to a lamination process in which an outer layer and an inner layer are stacked to form a multilayer printed wiring board without removing the electrodeposited coating OI. That is, there is an effect that the step of removing the electrodeposition coating is not necessary, and the oxide film treatment for the purpose of improving the adhesion to the epoxy resin on the surface of the inner copper layer, which was conventionally necessary, is no longer necessary.

[Effect of invention (device)]

As explained above, in this invention, the photoresist film is formed on the surface of the copper clad and FFI layer board by cationic electrodeposition coating, so there is no loss of material, automation is extremely easy, and It also contributes to quality stability and enables effective use of factory space.

Furthermore, the electrodeposited coating film formed can be strong enough to withstand gold plating solutions, so it is also effective in manufacturing gold-plated wiring boards.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a manufacturing process in a printed wiring board manufacturing method according to an embodiment of the present invention, and FIG. 2 is a sectional view showing an electrolytic cell in the above embodiment. FIG. 3 is a partial perspective view showing a printed wiring board produced by a conventional manufacturing method, and FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3. FIG. 5 is a cross-sectional view showing a manufacturing process in a conventional printed wiring board manufacturing method. In the figure, (1) is the insulating base material, (2) is the pattern, and (3) is the insulating base material.
) is land, (4) is through hole, (6) is panel copper plating, (7) is plating resist 2 (8) is pattern copper plating, the fabric is electrodeposition coating, 03 is electrodeposition paint water-soluble cationic resin It is. In each figure, the same reference numeral indicates the same thing.

Claims (2)

[Claims] (1) When forming a resist film on a part or the entire surface of a metal-clad laminated insulating board for printed wiring, including the inside of the through-holes of a printed wiring board having through holes such as through holes, the above-mentioned metal-clad laminated 1. A method for manufacturing a printed wiring board, comprising the step of immersing an insulating plate in a water-soluble resin for electrodeposition paint stored in an electrodeposition coating tank and depositing a cationic resist film by direct current electrolysis. (2) A printed wiring board according to claim 1, characterized in that a cationic resist film is formed as a step of automatic processing in an electrodeposition coating tank incorporated in a tank group for automatic processing. Production method.