JPH03217076A - Surface treatment of internal-layer base material for multilayer copper-clad laminated board - Google Patents

Abstract

PURPOSE:To enable a surface treatment film to be formed uniformly on an internal-layer base surface for stabilizing and improving contact with the internal-layer base material of a multilayer substrate and for enhancing the reliability by allowing a surface treatment liquid to be transferred onto the surface of the internal-layer base material by a transfer roller where the surface roughness is adjusted within a specific range for uniform adhesion, etc. CONSTITUTION:In a method for performing surface treatment onto an oxidized film surface of a copper foil 2 of an internal-layer base material 1 for forming a multilayer copper-clad laminated board, a surface treatment liquid 3 is transferred to the surface of the internal-layer base material for uniform adhesion by a transfer roller 6 where the surface roughness is adjusted to 5-150mum, thus forming a surface treatment film. For example, the internal-layer base material 1 which is suspended by a suspension tool 7 is allowed to pass through the transfer roller 6 while a draw-up roller 5 and the transfer roller 6 are rotated to enable the surface treatment liquid 3 which is drawn up by the draw-up roller 5 to be transferred to the internal-layer base material 1 by the transfer roller 6 and the surface treatment liquid 3 to be uniformly adhered onto the surface of the internal-layer base material 1. It is possible to use a metal whose surface roughness is adjusted to the above value, a hard roller such as a hard plastic, and a soft roller such as a soft plastic and a rubber as the transfer roller 6.

Description

[Detailed Description of the Invention] [Field of Application in Industry] The present invention relates to a method for surface treatment of an inner layer base material of a multilayer copper clad laminate using an insulating material such as an epoxy resin, and in particular to a method for surface treatment of an inner layer base material of a multilayer copper clad laminate using an insulating material such as an epoxy resin. The present invention relates to a surface treatment method for improving the adhesion between the oxidized surface of copper foil and a resin layer.

[Conventional technology]

In recent years, requirements for various properties of copper-clad laminates have become increasingly strict. This tendency is particularly noticeable in copper-clad laminates for industrial and consumer printed wiring boards. For example, demand for higher density has made signal lines thinner and thinner, and the strength of the bond between copper foil and resin has become important to ensure reliability. In addition, there is a remarkable trend toward multilayering, and the adhesive strength of copper foil is becoming more important not only between the roughened surface of the copper foil, but also between the shiny surface of the copper foil and the resin layer that adheres to it.

FIG. 2 is a system diagram showing the manufacturing process of a multilayer copper-clad laminate, which includes the manufacturing process of a multilayer board after manufacturing the inner layer base material.

Generally, the inner layer base material is 0.5 to 0. A double-sided copper-clad laminate with a thickness of about 6 mm is used, and after patterning (a) on the copper foil on both sides by etching etc. to form a predetermined circuit pattern, the surface is leveled (b) and washed with water (c). )
, drying (d). and oxidation treatment step (e
), the copper foil circuit pattern is oxidized to form an oxide film on the surface, and then dried (f). Thereafter, in a surface treatment step (g), surface treatment is performed using a coupling treatment liquid that generally contains a coupling agent, and after a drying step (h), the multilayer substrate manufacturing step (i) is started. In the multilayer board manufacturing process (i), the surface-treated inner layer base material and the prepreg made of glass cloth-epoxy resin are alternately laminated, and the outermost layer is laminated with copper foil and then heated and pressure molded. Manufactures multilayer copper-clad laminates.

Figure 3 is a cross-sectional view showing a conventional surface treatment device. In the figure, (1) is the inner layer base material, (2) is the copper foil circuit pattern laminated on both sides of the inner layer base material, and (3) is the surface treatment liquid. , (4
) is the processing liquid layer.

The conventional surface treatment method for the inner layer base material (1) is to use a surface treatment liquid (3) consisting of a coupling treatment liquid containing a coupling agent.
is placed in a treatment liquid tank (4), and the inner layer base material (1) on which the circuit pattern (2) is formed, which is the material to be treated, is immersed therein, then pulled up and dried, and the surface treated film is placed on the inner layer base material. Formed on the surface of material (1). After drying, the inner layer base material (1) is subjected to the next multilayer board manufacturing process.

[Problem to be solved by the invention]

However, in the conventional surface treatment method 3 mentioned above, the inner layer base material (1), which is the material to be treated, is simply
This method involved immersing the inner layer substrate (1) in a surface treatment liquid (3) containing a coupling agent, then pulling it up and drying it. Since there are parts where the circuit pattern (2) of the foil is formed and parts where it is not formed, it is not possible to uniformly form a uniform surface treatment film on the surface of the inner layer base material. For this reason, during the multilayer board manufacturing process, blistering and peeling may occur between the surface treatment film and the resin layer that adheres to it, significant variations in adhesive strength may occur in the multilayer board after manufacturing, and blistering and peeling may occur due to solder during mounting. There was a problem in that reliability was significantly impaired.

Conventionally, surface treatment liquids have a viscosity similar to that of water or solvents, and surface treatment films are colorless and transparent, and their thickness is extremely thin, so the relationship between the adhesion state of the surface treatment film and its adhesive strength has not been sufficiently studied. Ta.

The present invention has been made to solve the above-mentioned problems, and by uniformly forming a surface treatment film on the surface of the inner layer substrate, it stabilizes and improves the adhesion force with the inner layer substrate of the multilayer substrate. The purpose of the present invention is to propose a surface treatment method for inner layer substrates for multilayer copper-clad laminates, which can increase the reliability of multilayer copper-clad laminates.

[Means to solve the problem]

The method for surface treatment of an inner layer base material for a multilayer copper-clad laminate of the present invention includes:
In a method of surface-treating the surface of the oxide film of copper foil as an inner layer base material for forming a multilayer steel clad laminate, the surface roughness is set to 5 to 5.
In this method, a surface treatment liquid is transferred onto the surface of the inner layer base material using a transfer roller adjusted to have a thickness of 150 μm, and the surface treatment liquid is uniformly adhered thereto to form a surface treatment film.

As the surface treatment liquid used in the present invention, a coupling agent such as a silane coupling agent, a titanate coupling agent, or a mixed coupling agent of both may be used in an amount of 0.3 to
An example is a surface treatment liquid containing 5% by weight.

[For production]

In the method for surface treatment of an inner layer base material for a multilayer copper-clad laminate according to the present invention, a surface treatment liquid is transferred to the inner layer base material using a transfer roller whose surface roughness is adjusted to 5 to 150 μm, and the surface treatment liquid is uniformly adhered to the inner layer base material. Surface treatment is performed to form a surface treatment film.

When the inner layer substrate, which is the material to be treated, is immersed in a surface treatment liquid and pulled up as in the conventional method, the surface treatment liquid attached to the surface does not adhere uniformly to the surface due to repellency or liquid clumps on the surface of the inner layer substrate. First, a uniform surface treatment film cannot be formed, but this is because the surface tension is large when the surface treatment liquid comes into contact with the surface of the inner layer base material of the material to be treated. Therefore, in the present invention, by transferring the surface treatment liquid onto the inner layer base material using a transfer roller whose surface roughness is adjusted to the above range, the surface treatment liquid is uniformly adhered to the surface of the inner layer base material. Forms a surface treatment film.

[Embodiments of the invention]

Examples of the present invention will be described below.

FIG. 1 is a cross-sectional view of a surface treatment apparatus used in an example, and in the figure, the same reference numerals as in FIG. 3 indicate the same or corresponding parts. The surface treatment device consists of 1 in which the surface treatment liquid (3) is placed
A pair of treatment liquid tanks (4), a pair of pumping rollers (5) provided so as to partially contact the surface treatment liquid (3) in the processing liquid tank (4), and a pumping roller (5) provided so as to partially contact the surface treatment liquid (3) in the processing liquid tank (4). A pair of transfer rollers (6) provided facing each other so as to be in contact with
). The surface roughness of the transfer roller (6) is 5~
A hard roller made of metal, hard plastic, etc. adjusted to 150 μm, or a soft roller made of soft plastic, rubber, etc. can be used. The surface treatment liquid (3) pumped up by the pumping roller (5) is transferred onto the inner layer base material (1).

The surface treatment method for the inner layer base material (1) includes rotating the transfer roller (5) and the transfer roller (6).
6) Inner layer base material (1) suspended by a hanging jig (7) between
, the surface treatment liquid (3) pumped up by the pumping roller (5) is transferred to the inner layer base material (1) by the transfer roller (6), and the surface treatment liquid (3) is transferred to the inner layer base material (1). 1) Apply it uniformly to the surface.

At this time, the transfer roller (6) presses against both sides of the inner layer base material (1), despite the warpage or bending of the inner layer base material (1), or the unevenness caused by the presence or absence of the circuit pattern (2) on its surface. The surface treatment liquid (3) is uniformly applied to all the uneven surfaces of the base material (1). The adhesion state of the surface treatment liquid (3) to the transfer roller (6) can be controlled by controlling the inner layer base material (1), the gap between the rollers, the material of the roller, etc., and especially the roughness provided on the surface. Due to the fine irregularities caused by the surface treatment liquid (3), the pumping roller (
5) can be uniformly received from the inner layer base material (1) and attached to the surface of the inner layer base material (1).

Example 1 First, as the inner layer base material (1), a copper-clad laminate made of glass cloth-epoxy resin having a total thickness of 0.60 mm and having a copper foil of 70 μm thick on both sides was used. First, in the patterning step (a) shown in FIG. 2, a resist is applied to the copper foil on both sides so as to form a predetermined pattern, and patterning is performed by etching or the like to form a circuit pattern (2). This pattern surface is leveled (b), washed with water (c), and dried (d).
After the oxidation treatment step (e), a blackening treatment solution (sodium chlorite 31g/Q, sodium hydroxide 15g/Q) is applied.
Q. After forming an oxide film by immersing it in an aqueous solution of trisodium phosphate (12 g/Ill) at 95°C for 2 minutes, it was immersed at 150°C.
Dry (f) for 15 minutes in an oven.

Next, as a surface treatment step (g), a coupling treatment solution (
A surface treatment solution (2% by weight of β-(3,4-epoxyhexyl)ethyltrimethoxysilane, 0.5% by weight of acetic acid, 60% by weight of ethanol, 37.5% by weight of water)
3) and transfer it to the treatment liquid tank (
4) and pumped up with a pumping roller (5), and on the other hand, the inner layer base material (1) on which the patterning and oxide film were formed was suspended by a hanging jig (7), and the surface roughness was 20 to 30 μm.
A rubber roller with a diameter of 50 mm that has a fluororesin (Teflon) film polished to a hardness of JIS A.
A pressing force of 500° is applied between the transfer rollers (6) consisting of
The surface treatment liquid (3) is passed through the inner layer base material (1) under the conditions of g.
) and attached to it. Thereafter, it was air-dried at room temperature for 10 minutes, and then dried in an oven at 110° C. for 30 minutes (h) to form a surface-treated film of the coupling agent.

In the multilayer board manufacturing process (i), the inner layer base material (1) on which this surface treatment film is formed is laminated with a required number of layers alternately with a prepreg (not shown) made of glass cloth-epoxy resin, and the outermost layer is A multilayer copper-clad laminate was obtained by laminating copper foil and press-molding.

Comparative Example 1 A multilayer copper-clad laminate was obtained in the same manner as in Example 1, except that the surface treatment apparatus shown in FIG. 3 was used.

Regarding the multilayer copper-clad laminates of Example 1 and Comparative Example 1, the peeling force between the surface-treated copper foil and the prepreg was measured. The results are shown in Table 1.

Table 1 *1: Peeling force is JIS-C-6481. Tested according to 5.7.

Also, the surface roughness of the transfer roller (6) and the surface treatment liquid (3)
As a result of experiments on uniform adhesion, the surface roughness was 5 to 1.
It was found that uniform adhesion was possible by setting the thickness to about 50 μm.

In addition, in the method of the present invention, not only a surface treatment liquid containing a coupling agent but also a commonly available primer or adhesive can be used as the surface treatment liquid.

Further, in the above embodiment, the number of transfer rollers (6) for uniformly forming the surface treatment film is not limited to one pair, but several pairs may be installed to perform the treatment in stages. Further, roughness may be imparted to the surface of the transfer roller (6) by coating the surface with a cylindrical mesh or by disposing a sponge-like material.

〔Effect of the invention〕

As described above, according to the present invention, a uniform surface treatment film is formed on the surface of the inner layer base material by transferring the surface treatment liquid onto the inner layer base material and making it adhere uniformly using a transfer roller with adjusted surface roughness. It can be formed easily and evenly, thereby stabilizing the adhesive force and improving its level, which has the effect of contributing to improving the yield and reliability of multilayer copper-clad laminates.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a surface treatment apparatus according to an embodiment, FIG. 2 is a system diagram showing the manufacturing process of a multilayer copper-clad laminate, and FIG. 3 is a sectional view of a conventional surface treatment apparatus. In each figure, the same reference numerals indicate the same or corresponding parts, (1)
is the inner layer base material, (2) is the circuit pattern, (3) is the surface treatment liquid, (4) is the treatment liquid tank, (5) is the pumping roller, (6)
is a transfer roller, and (7) is a hanging jig.

Claims (1)

[Claims] (1) In a method of surface-treating the oxide film surface of copper foil as an inner layer base material for forming a multilayer copper-clad laminate, a surface treatment liquid is applied to the inner layer base material using a transfer roller with a surface roughness adjusted to 5 to 150 μm. A method for surface treatment of an inner layer base material for a multilayer copper-clad laminate, characterized by forming a surface treatment film by transferring and uniformly adhering it to the surface of the material.