JPH04174596A - Manufacture of multilayered printed wiring board - Google Patents

Abstract

PURPOSE:To arrange facilities in a series so as to prevent substrates from being broken or damaged by forming an oxide film on the surface of the copper layer of a substrate for inner layer and performing circuit formation by a photoetching method using a film of a conductive and photosensitive resin. CONSTITUTION:A copper plated layer 4 is deposited on the surface of the copper foil 2 and inner surfaces of holes 3 of a substrate 1 provided with the holes 3 at prescribed places and the copper foil 2 on the surface by chemical or electric copper plating treatment. Then, after an oxide film is formed on the surface of the layer 4, the oxide is reduced to metallic copper by performing reduction treatment. After the oxide film is reduced, a film 5 of a conductive and photosensitive resin (ED) is formed. Then, after a pattern is formed by exposing and developing the film 5, the copper layer is patterned by etching. Thereafter, a substrate 1 for inner layer is obtained by removing the film 5 before a laminating process is started. When such method is used, the facilities used for the manufacturing process from the copper plating process to the ED film forming process can be arranged in a series and the breakage and damage of substrates can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a multilayer printed wiring board, and more particularly to a method for manufacturing a multilayer printed wiring board that allows for serialization of equipment.

[Conventional technology]

In general, the manufacturing method for multilayer printed wiring boards having inner layer peer holes involves drilling holes at predetermined locations in a copper-clad laminate with copper foil provided on one or both sides, and then applying chemical copper plating or electrolytic copper plating. Through holes are formed by copper plating. Next, a circuit is formed by photoetching, and an oxide film is formed on the surface of the circuit copper plating layer.

A plurality of inner layer substrates produced by the above method are laminated with silver foil or one or both surfaces of outer layer circuit boards via prepreg, pressurized, and heated to form a multilayer printed wiring board.

[Problem to be solved by the invention]

In the conventional method for manufacturing multilayer printed wiring boards described above, the circuit forming process is inserted between the copper plating process and the process of forming an oxide film on the surface of the circuit copper plating layer, so the equipment can be integrated into a series. Since the board is divided, manual intervention is required to transport it between processes, which poses a problem in that the board may be bent or damaged during handling, leading to defects.

In addition, by forming an oxide film on the surface of the 8th plating layer, the surface area is increased and an oxide with a fine structure is formed to obtain adhesion with the resin. If left for a long time before the process of applying pressure and heating to form a multilayer printed wiring board, the surface condition of the circuit copper plating layer will change, and if left for a long time, the same treatment will need to be repeated. there were.

An object of the present invention is to produce a printed wiring board that allows for serialization of equipment, that does not cause bending or damage to the board due to manual intervention during transportation, and that does not cause deterioration of the surface condition of circuit steel plating due to long-term storage. Our goal is to provide the following.

[Means to solve the problem]

The method for manufacturing a multilayer printed wiring board of the present invention includes the steps of forming an oxide film on the surface of the copper layer of an inner layer substrate whose surface is coated with a copper layer, reducing the oxide film, and reducing the oxide film. The method includes the step of forming a circuit on the surface of the steel layer by photoetching using a conductive photosensitive resin film.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) to 1(g) are sectional views showing a first embodiment of the present invention in order of steps.

In the first embodiment, first, as shown in FIG. 1(a), a substrate 1 is prepared, in which holes 3 are bored at predetermined locations and steel foil 2 is provided on the surface.

Next, as shown in FIG. 1(b), a copper plating layer 4 is deposited on the surface of the copper foil 2 and on the inner wall surface of the 63 by chemical copper plating or electrolytic copper plating.

Next, as shown in FIG. 1(c), an oxide film is formed on the surface of the plating layer 4, and then reduced to metallic copper by a reduction treatment.

Next, as shown in FIG. 1(d), a conductive anti-glare resin (hereinafter referred to as ED) film 5 is formed on the surface of the copper plating layer 4.

Next, as shown in FIG. 1(e), E
A pattern of the D cover 1115 is formed.

Next, as shown in Part 1 (f), a pattern of the copper layer is formed by etching and socinc.

Next, as shown in FIG. 1<g), the ED coating 5 is peeled off before the lamination step to obtain an inner layer substrate.

By the above method, it is possible to integrate the equipment from the copper plating process shown in FIG. 1(b) to the ED film forming process shown in the first g(d).

FIGS. 2(a) to 2(f) are sectional views showing a second embodiment of the present invention in order of steps.

The first embodiment shown in FIGS. 1(a) to (g) was for an inner layer substrate having through holes, and the second embodiment was for an inner layer substrate without through holes. This is an example.

In the second embodiment, as shown in the second [3(a)], first,
A substrate 1 having a silver foil 2 provided on its surface is prepared.

The oxidation-reduction step shown in FIG. 2(b) and subsequent steps are carried out in exactly the same manner as the steps shown in FIG. 1(c), thereby obtaining an inner layer substrate.

By the above method, it becomes possible to integrate the equipment from the step of treating the oxide film on the surface of the copper layer shown in FIG. 2(b) to the step of forming the ED film shown in FIG. 2(c).

〔Effect of the invention〕

As explained above, the present invention introduces a reduction treatment after forming an oxide film on the surface of a copper layer, and performs these treatments before circuit formation by forming an ED film, thereby reducing the plating process and the surface of the copper layer. The equipment for the three steps of oxidation-reduction treatment and circuit formation using an ED coating can be integrated into a series, which has the effect of creating a streamlined, unmanned line.

Furthermore, since it protects the oxide film on the surface of the ED-coated copper layer, peeling off the ED film before lamination has the effect of eliminating the need for reprocessing to form an oxide film due to long-term storage.

[Brief explanation of drawings]

FIGS. 1(a) to <g) are cross-sectional views showing the steps of the first embodiment of the present invention, and FIGS. 2(a) to (f) illustrate the second embodiment of the present invention. FIG. 1... Board, 2... Copper foil, 3... Hole, 4... Copper plating layer, 5... ED coating

Claims (1)

[Claims] A step of forming an oxide film on the surface of the copper layer of the inner layer substrate whose surface is coated with a copper layer, a step of reducing the oxide film, and a step of forming an electrically conductive photosensitive film on the surface of the reduced copper layer. A method for manufacturing a multilayer printed wiring board, comprising the step of forming a circuit by a photoetching method using a resin film.