JPS6298696A - Formation of multilayer 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] [Field of Application of the Invention] The present invention relates to a method for forming a multilayer wiring board, and in particular has excellent adhesion to an insulating substrate, and has fine and highly accurate copper wiring. The present invention relates to a method for forming a highly functional and highly reliable multilayer board suitable for forming a multilayer board.

[Background of the invention]

Various methods are used to increase the adhesive strength between metal and resin. For example, for metals, there are methods such as mechanical polishing treatment and chemical etching roughening treatment. In addition, for the purpose of improving the adhesion of resins with metals through mechanical projection effects, roughening treatment methods such as etching (Katsuji Yajima, Tokuzo Kobe: Effect of etching liquid on polypropylene resin) .

Metal Surface Technology, 23.380 (1972). In addition to these methods, it is also possible to oxidize the surface of metal or resin (Eita: Printed wiring materials and processing technology, ■CMC).

p 77 (1981), Kozo Sato, Adhesion of paint films, @
(Riko Publishing, p. 163 (1981)) A method of increasing the adhesive strength between metal and resin has also been used. but,
When resin and metal are bonded using these methods, since oxides are used, it is difficult to say that it is possible to form a resin-metal composite with high reliability (and sufficient adhesive strength). However, apart from these methods, when producing copper foil by plating, the surface of the silver foil is roughened to have large irregularities and then electrodeposited, and this copper foil and prepreg are bonded together. It is possible to form a resin-metal composite with high properties. Therefore, copper foil using this copper foil
A copper wiring pattern is formed on the resin sheet by creating a sheet made of a resin composite, forming a resist pattern on the copper foil, etching, and then removing the resist. However, the surface of the copper foil in contact with the resin has large irregularities, and the resin and the copper foil dig into each other in a complicated manner, making etching difficult and thus making it difficult to form fine copper wiring patterns. Therefore, when a multilayer board is formed using a copper wiring board in this way, it is difficult to form a multilayer board with copper wiring that has excellent adhesion between the resin and the copper wiring and has good pattern accuracy. It is.

In addition, a method of forming a wiring board that accurately forms fine patterns and has excellent adhesion to the resin board is to apply an adhesive on the resin board, and then apply an insulating layer to the non-circuit portions. There is a method of forming a resin pattern and then forming a copper plating film on the circuit part, but there is a problem that the adhesive has poor heat resistance. Therefore, when attempting to form a multilayer board using these wiring boards, there is a problem that the shape of the wiring pattern cannot be maintained during bonding, resulting in poor wiring pattern accuracy.

[Purpose of the invention]

An object of the present invention is to provide a method for forming a wiring board having copper wiring that has excellent adhesiveness to a resin board and has a highly accurate pattern.

[Summary of the invention]

Conventional methods have not been able to provide a wiring board that satisfies the above objectives. In the present invention, the adhesiveness of the copper foil to the resin plate is improved by using a copper foil that has been electrodeposited so that the surface of the copper foil has large irregularities.
A copper foil composite can be obtained. In addition, in order to form copper wiring with a high-precision pattern, a resist pattern is formed on the resin board in the area corresponding to the non-circuit area, and copper is deposited only on the circuit area, or a thin conductive layer is formed on the entire surface. A metal film is applied, then a resist pattern is formed on the parts corresponding to the non-circuit parts, then copper is thickly formed only on the parts corresponding to the circuit parts, and then the resist is peeled off and a circuit is formed by etching. There are ways to do this.

Therefore, based on these findings, the present inventors formed a copper wiring board that can satisfy the above object by the method described below. The outline is shown below.

Apply adhesive (2) to the sheet shown in Figure 1 (1) for 40 minutes.
Apply particles that do not deform even at temperatures of 0°C. Next, as shown in (b), the surfaces of these sheets to which the particles are attached are placed facing each other, and the sheets are heated, processed, and bonded using prepreg. Next, as shown in (c), the sheet is peeled off, and then, as shown in (d), the particles are dissolved and removed to maintain the particle shape on the surface of the cured resin. Next, after applying a catalyst, a resist pattern is formed in the non-circuit part using a photosensitive resin (e), and then copper wiring is formed in the five circuit parts by chemical steel plating (f). Thereafter, the resist pattern is peeled off, the catalyst is removed, or the tri-film is left as a permanent resistor, and these copper wiring boards are laminated and bonded using prepreg, and a multilayer printed board 1-board is formed by a conventional method. do.

Further, after the step (d), chemical plating is thinly formed on the entire surface as shown in FIG. Then (f
As shown in )', thick copper is formed on the circuit part by chemical plating. Thereafter, as shown in (g)', the resist pattern is removed and etching is performed to remove non-circuit copper. Thereafter, these copper wiring boards are laminated and bonded using prepreg to form a multilayer printed board according to a conventional method.

[Embodiments of the invention]

The present invention will be explained in detail below.

Example 1 As shown in Figure 1(a), vegetable glue was applied onto a smooth paper, and fine powder of iron oxide (particle size 10 μm) was applied without drying.
Place the powder (below) and dry.

After the glue has dried, these sheets are laminated and bonded via prepreg by heating and pressure, with the surface to which the fine powder is attached facing inward, as shown in (b). The paper and glue are then removed using warm water. Next, hydrochloric acid (10%)
The iron oxide is dissolved to obtain a hardened resin plate having a surface shape as shown in (d). After applying a catalyst for chemical copper plating to this, a resist pattern is formed using a photosensitive resin (e), and then a copper plating film is formed on the circuit portion by chemical copper plating (f). Next, these wiring boards and prepreg are stacked alternately, and a wiring board with no copper wiring formed on one side of the outermost layer is laminated and bonded, a through hole (8) is formed in the pad part, and a catalyst After applying, a resist pattern is formed on the outermost layer, and chemical copper plating is applied.
The inside of the through hole and the outermost layer are plated with copper to form a wiring circuit (g). As a result, good results were obtained, with the copper wiring (μm)/copper wiring spacing (μm) being 60/60 with good accuracy, and the beer strength of the copper wiring against the resin plate being 1.3 kg/■. Ta.

Example 2 A test was carried out using zinc oxide instead of the iron oxide fine particles used in Example -. The rest of the process was the same as in Example 1. As a result, copper wiring (μm)/copper wiring spacing (
Good results were obtained, with a good accuracy of 60/60 μm) and a beer strength of 1.5 kg/■ of the copper wiring against the resin plate.

Example 3 The experiment was carried out using lucium carbonate instead of the iron oxide fine particles used in Example 2, and a 20% sulfuric acid solution containing 30 g/fl of chromium ions as a liquid for removing lucium carbonate instead of hydrochloric acid. did.

The rest of the process was the same as in Example 1. As a result, the copper wiring (μm)/copper wiring spacing (μm) was 60/60 with good accuracy, and the beer strength of the copper wiring against the resin plate was 1.5 kg/cxn, giving good results. Ta.

Example 4 Instead of using a sheet with iron oxide fine particles attached as shown in Figure 1-(a) in Example 1, the surface was JTSI30.
In the ten-point average roughness described in 601, when the reference length L is 100 μm, a copper foil with Rz of 15 μm is used and bonded using prepreg in the same manner as in (b),
Thereafter, the copper foil was dissolved with nitric acid to create a sheet as shown in Figure (d).

The other conditions were the same as in Example 1.

As a result, the copper wiring (μm)/copper wiring spacing (μm) was 60
/60 had good accuracy, and the beer strength of the copper wiring against the resin was 1°5 kg/am, which was good.

〔Effect of the invention〕

According to the present invention, as a copper wiring for a multilayer printed board, the adhesiveness with the resin is 1-/■ in beer strength, and the copper wiring width (μrn)/copper wiring spacing (μm) is 60/60.
Since fine copper wiring can be made uniform with high precision, it is effective as a multilayer printed circuit board on which semiconductor elements are mounted to operate large-scale computers with high reliability and high calculation speed.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of a process for making a multilayer pudding 1-board according to an embodiment of the present invention. 1... Hygroscopic paper or cloth, 2... Glue, 3...
Fine particles, 5...Catalyst, 6...Resist, 7...Chemical copper plating film, 1-, S・N

Claims (1)

[Claims] 1. A step of attaching a resin to a copper foil having a roughened surface and curing the resin. A step of removing the attached copper foil from the surface of the resin by etching. A step of applying a catalyst to the surface of the resin. It is characterized by the process of forming a resist pattern in non-circuit areas using a photosensitive resist filter, the process of forming copper wiring by chemical plating on the catalyst in the circuit area, and the lamination and adhesion of prepreg using this copper wiring board. A method for forming a multilayer wiring board.