JPS6158733A - Inner layer board for multilayer substrate - 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] [Technical field of invention] The present invention relates to an inner layer plate for a multilayer board.

[Technical Background of the Invention] Conventionally, the following method has been used to manufacture an inner layer board for a multilayer board.

First, a plurality of sheets of prepreg are laminated, copper foil is placed on the outermost layer, and the inner layer board is manufactured by press-molding them together. Then,
An inner layer circuit pattern is formed on a 1 mm board to form an inner layer circuit board, and a predetermined number of inner layer circuit boards are laminated while interposing a prepreg serving as an adhesive layer and an insulating layer. Thereafter, copper foil or a copper-clad laminate is placed on top of the outermost layer with the copper foil side facing outward, and these are heat-pressed and bonded together by press molding.

In forming the inner layer circuit, the surface of the copper-clad laminate is smoothed to improve adhesion, and then a photosensitive film is attached to form an etching resist layer, followed by fogging and development. Thereafter, etching is carried out by a conventional method, and after the etching, the etching resist layer is peeled off and the exposed circuit surface is oxidized to improve its adhesion to the prepreg.

[Problems with the Background Art] However, in forming the inner layer circuit of a multilayer board, special equipment is required to go through many steps as described above. Since it is necessary to oxidize the foil, there is a drawback that processing unevenness may occur depending on the pattern density of the circuit on the circuit surface. Furthermore, since the oxidation treatment is carried out on small-sized panels, there are problems in terms of productivity, and since the treated surface of the circuit is exposed until multilayer molding, there are also restrictions on storage stability. Ta.

[Object of the Invention] The present invention was made in order to eliminate such conventional drawbacks, and it is possible to reduce the size of the copper foil surface to a large size (for example, 200 x 20
Productivity can be improved by blackening the copper foil surface (0 mm or more), and by coating the surface of the copper foil with a photosensitive etching resist, the treated surface is protected, and this coating material can be used for circuits. The present invention provides an inner layer board for a multilayer board that can also be used for forming.

[Summary of the Invention] That is, the inner layer board for a multilayer board of the present invention is produced by laminating a plurality of sheets of prepreg, placing a copper foil on the outermost layer, press-molding them together, and coating the surface of the copper foil with a photosensitive etching resist. It is characterized by the fact that

The inner layer board for a multilayer board of the present invention requires a prepreg obtained by impregnating and drying a resin such as epoxy resin or polyimide resin on an undefined base material such as glass cloth or glass paper or a 1-fill base material such as polyaramid 4J & fiber. Layer up several sheets, place copper foil on both sides or one side, insert between stainless steel plates, and heat and pressurize with a molding press to form copper-plated g.
It can be manufactured by forming a one-layer plate, then applying a photosensitive etching resist to the surface and drying it.

The copper foil surface of the copper clad laminate is subjected to blackening treatment as a pretreatment.

The inner layer board for a multilayer board according to the present invention has the advantage that the blackening treatment of the copper foil surface can be performed on a relatively large size, so that productivity can be improved.

After the above treatment, the copper foil surface is coated with a photosensitive etching resist using a roll coater or dipping method to obtain the inner layer plate for a multilayer board of the present invention.

As the photosensitive etching resist, a polymer having an epoxy group and one or more photosensitive groups is suitable. Examples of the above-mentioned photosensitive group include a group having an ethylenic double bond such as an acrylic group and a methacrylic group.

The inner layer plate for a multilayer substrate thus obtained is usually stored, transported, etc. in a light-opaque container. Then, if necessary, the inner layer circuit pattern is formed by exposure and etching after development, and the required number of V4 layers are formed by interposing prepreg, and the outermost layer is covered with copper foil or copper clad laminate, and then integrated by pressing. A multilayer substrate is manufactured by pressure molding.

FIG. 1 schematically shows the structure of the multilayer board manufactured in this way. 1 is an inner layer board with an inner layer circuit pattern 2 formed on its surface, 3 is a prepreg, 4 is a copper foil, and 5 is an etched board. Showing resist layer.

As mentioned above, the etching resist for the inner layer board for a multilayer board of the present invention has an epoxy group and a photosensitive group, so it is possible to form a circuit pattern. has the advantage that the curing agent and epoxy group in the prepreg react and cure together. There is also the advantage that there is no need for peeling after etching, which shortens the process and eliminates the need for special peeling equipment. Furthermore, since the film thickness of the etching resist can be made thinner, there is also the advantage that etching of fine patterns becomes easier.

[Embodiments of the invention] Next, examples of the present invention will be described.

Example As shown in FIG. 2, the size is 510mm x 5101m x 0.
The surface of the copper foil of 4mm glass-epoxy resin double-sided copper-clad laminate (TLC-W-55170μFR-4 grade manufactured by Toshiba Chemical Corporation) 6 was coated with sodium chlorite 45Q/12,
Caustic soda 10CJ/pu, sodium phosphate 15g/
The sample was treated for 5 minutes in a 90°C oxidation bath having a composition of λ.

Then PROB IM was used as a photosensitive etching resist.
Using an ER48 (manufactured by Ciba Geigy) solution, the above-mentioned copper-clad laminate was immersed in this solution and dried at 80° C. for 30 minutes to form a photosensitive etching resist layer with a thickness of about 9 μm.

Thereafter, an inner layer circuit pattern was exposed on this photosensitive etching resist layer, developed with cyclohexane, and then etched with chromium t[Q.

In the figure, 7 is the inner layer circuit pattern obtained in this manner, and 8 is an etching resist layer.

After drying the inner layer circuit board thus obtained at 120°C for 40 minutes, three sheets of prepreg (glass cloth, thickness 0
．． 18a) Layer copper foil (TL-18μ manufactured by Fukuda Metal Foil and Powder Industries Co., Ltd.) 10 on both sides with 9 interposed, and heat at 170°C.
The molding process was carried out for 60 minutes at a constant pressure of 40 kg/T11' to form a 4-layer board. The properties of this four-layer epoxy board were as shown in the table.

In general, glass cloth-epoxy copper-clad laminates manufactured using conventional inner layer boards tend to have somewhat poor adhesion when heat resistance is added, but as shown in the table above, using the inner layer board of the present invention This tendency is not observed in the 4-layer epoxy board manufactured by the above method, and the quality is sufficient to withstand the processing conditions and purpose of use of the multilayer board.

[Effects of the Invention] As explained above, since the inner layer board for a multilayer board of the present invention is a copper foil coated with a photosensitive etching resist, the user can shorten the process in one step.
By oxidizing the inner layer copper foil in advance and cutting multiple layers, productivity can be significantly improved, and costs can thereby be reduced.

[Brief explanation of drawings]

FIG. 1 is a sectional view schematically showing the structure of an inner layer plate for a multilayer board according to the present invention, and FIG. 2 is a diagram for explaining the structure of the inner layer plate for a multilayer board according to an embodiment of the present invention. 1.6... Internal retaining board 2.7... Inner layer circuit pattern 3.9... Prepreg 4.10... Copper foil 5.8...・Sasa Suyama, Patent Attorney for Etching Resist Layer - Figure 1 Figure 2

Claims (3)

[Claims] (1) An inner layer board for a multilayer board characterized by laminating a plurality of sheets of prepreg, placing a copper foil on the outermost layer, press-molding them as one body, and coating the surface of the copper foil with a photosensitive etching resist. . (2) The inner layer plate for a multilayer substrate according to claim 1, wherein the photosensitive etching resist is made of a polymer having an epoxy group and a photosensitive group. (3) The inner layer board for a multilayer board according to claim 1 or 2, wherein the copper foil is surface-treated in advance.