JPH0697670A - Board for multilayer printed wiring - Google Patents

Abstract

PURPOSE:To obtain a board for multilayer printed wiring which improves drilling machinability, resistance to haloing and decrease in permittivity without damaging size stability with respect to heat. CONSTITUTION:A board for multilayer printed wiring wherein a glass-cloth-base prepreg sheet B and a copper foil 4 are arranged respectively on the front and rear sides of a glass nonwoven-fabric base prepreg sheet A and these are laminated into one body, and on the front and rear sides of a double-sided copper-clad laminated board of this complex structure, a glass cloth base prepreg sheet C in which the quantity of resin is increased by attaching a 50-55% of epoxy resin to a glass cloth of 0.18mm nominal thickness and the copper foil 4 are laminated respectively, and then the whole substrate is heated and pressed into one body of lamination.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for a multilayer printed wiring board.

[0002]

2. Description of the Related Art With the progress of higher functionality and smaller size and lighter weight of electronic equipment, the multilayered and high density of printed wiring boards has been advanced. Conventionally, such a multilayer printed wiring board is made by forming each insulating layer using a glass cloth base material prepreg sheet (glass epoxy base material) obtained by impregnating glass cloth with an epoxy resin and drying. . However, although such a structure is excellent in dimensional stability because the reinforcing base material is only glass cloth, it has the following potential problems. 1) Since the glass component is harder than the epoxy resin component, the wear of the drill blade is fast, and the composition with many glass components shortens the life of the drill blade. 2) The glass cloth of the laminated glass epoxy substrate and the glass cloth easily come into contact with each other without interposing the resin layer, which may cause various problems in the subsequent processing steps. The problem of white spots on the intersection of glass cloth called Miesling. Since the contact surface has a small amount of resin layer, the adhesive strength is low, and it is easy for micro-cracks to occur due to mechanical shock or thermal shock, and haloing (blackening treatment applied to improve the adhesive strength of the inner layer circuit surface , A phenomenon in which the adhesive force is impaired by the penetration of the plating solution from the through holes and the adhesive strength is reduced) or migration (copper ions extend along the glass cloth fiber between two points with a potential difference under high temperature and high humidity conditions, causing a short circuit). Problem that tends to contribute to the phenomenon leading to. 3) The glass component has a high dielectric constant (at 1 MHz, ε
= 5.8), it is effective to reduce the dielectric constant by increasing the resin component.
When more than one sheet is stacked and multi-layered, there is a problem that a slip phenomenon is likely to occur during heating and pressurization.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multilayer printed wiring board which has improved drilling workability, haloing resistance, low dielectric constant and the like without impairing dimensional stability against heat. It was made.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is to laminate a glass cloth base material prepreg sheet with a glass cloth base material prepreg sheet and a copper foil on the upper and lower surfaces of the glass non-woven fabric base material, and heat and press the whole to laminate them. A glass cloth base material in which a desired circuit pattern is formed on the copper foils on the upper and lower surfaces of the integrated composite-structured copper clad laminate as an inner layer material, and the resin amount is increased one by one on the upper and lower surfaces of the inner layer material. The prepreg sheet and the copper foil were superposed on each other by heating and pressurizing the whole so as to be laminated and integrated. The glass cloth base prepreg sheet used for the upper and lower surfaces of the core layer had a nominal thickness of 0.18 m.
It is preferable that the glass cloth of m contains 50 to 55% of the epoxy resin.

[0005]

[Function] As an insulating adhesive layer of the inner layer circuit board used for the core layer, the glass cloth base material prepreg sheets are stacked on the upper and lower surfaces of the non-woven fabric base material prepreg sheet to form a glass cloth base material hard against a drill. Drill workability is improved compared to the case where only material prepreg sheet is used. Nominal thickness of 0.
By using a resin amount up prepreg sheet made by adhering 50 to 55% of epoxy resin to 18 mm glass cloth, the resin layer can be retained at the adhesive interface and the measling or haloing that easily occurs in the portion with a small amount of resin. Has the effect of suppressing the occurrence of. By using the glass cloth base material prepreg sheets one by one, the layers having a large amount of resin are not overlapped, and the slip phenomenon at the time of multilayer pressing can be avoided. Furthermore, the glass non-woven fabric layer having a relatively large amount of resin and the resin amount increasing prepreg layer can reduce the glass component having a high dielectric constant, thereby lowering the dielectric constant.

The present invention will be described below with reference to the drawings of submitted properties by way of examples and comparative examples.

EXAMPLE FIG. 1 is an explanatory view for explaining the constitution of the base material of the example. First, a glass nonwoven fabric prepreg sheet A, a glass cloth substrate prepreg sheet B, and a glass cloth substrate prepreg sheet C are prepared. (A) Glass non-woven fabric substrate prepreg sheet A: (i) Glass non-woven fabric: GMC-00 manufactured by Honshu Paper Co., Ltd.
-050 (E) (ii) Resin varnish I: As an epoxy resin, a low brominated epoxy resin (DER-511 manufactured by Dow Chemical Co.) 100 parts As an epoxy resin curing agent, dicyandiamide 2.1 parts As a curing accelerator, 2 ethyl 4-Methylimidazole 0.15 parts As a solvent, DMK 30 parts MEK 10 parts The above glass nonwoven fabric was impregnated with the above resin varnish I and dried to a semi-cured state to obtain a glass nonwoven fabric base material prepreg sheet A. (B) Glass cloth base material prepreg sheet B: (i) Glass cloth: 7628 manufactured by Asahi Shovel Co., Ltd.
AS905 (ii) Resin varnish: The resin varnish I used for the glass nonwoven fabric base material prepreg sheet A is used. The glass cloth (nominal thickness 0.18 mm) was impregnated with the resin varnish I and dried to a semi-cured state to obtain a resin content of 42%.
A glass cloth-based prepreg sheet B was obtained. (C) Glass cloth base material prepreg sheet C: (i) Glass cloth: The glass cloth used for the glass cloth base material prepreg sheet B is used. (Ii) Resin varnish: The resin varnish I used for the glass nonwoven fabric base material prepreg sheet A is used. Resin varnish I on glass cloth (nominal thickness 0.18 mm)
Was impregnated and dried to a semi-cured state to obtain a glass cloth base material prepreg sheet C having a resin content of 52%. Next, an inner layer circuit board is created using the prepreg sheet. The inner layer circuit boards are glass nonwoven fabric prepreg sheets A, and two glass cloth substrate prepreg sheets B are provided on the upper and lower surfaces, respectively.
And the copper foil 4 are superposed, and the whole is heated and pressed to form a laminated double-sided copper-clad laminate having a composite structure, and the copper foil on the surface layer of the double-sided copper-clad laminate of this composite structure is etched by an etching method or the like. A desired circuit pattern 1 and a target mark for alignment (not shown in the drawing) were formed to obtain an inner layer circuit board 2. Next, the glass cloth base material prepreg sheet C and the copper foil 4 were superposed on the upper and lower surfaces of the inner layer circuit board 2, respectively, and the whole was heated and pressed to be laminated and integrated to obtain a 4-layer printed wiring board with an inner layer circuit. . The dimensional stability, drilling workability, haloing resistance, and dielectric constant of this 4-layer printed wiring board were measured or observed and shown in Table 1. The dimensional stability was evaluated based on the rate of change of the reference pitch with respect to the reference set value after the target mark was spotted after the multilayer press molding. For drilling workability, stack two multi-layer boards with a thickness of 1.6 mm and use a 0.4 mmφ drill blade at a rotation speed of 7
4000 shots were taken at 0000 rpm, and the degree of remaining drill blade was evaluated. The haloing resistance was evaluated by opening a 1.1 mmφ hole, immersing it in 12% hydrochloric acid at 50 ° C. for 3 minutes, and then mechanically peeling the interface between the core layer and the prepreg layer to determine the maximum permeation length around the hole. . As for the dielectric constant, the outer layer copper foil is removed by etching, and the part without the inner layer circuit pattern is JISC6.
It measured based on 481.

[0007]

[Comparative Example 1] First, three glass cloth-based prepreg sheets B used in the examples were superposed, copper foils 4 were superposed on the upper and lower surfaces thereof, respectively, and the whole was heated and pressed to be laminated and integrally laminated on both sides. A laminated board is formed, and a desired circuit pattern 1 and a target mark for alignment (not shown in the drawing) are formed on the copper foil of the surface layer of the double-sided copper clad laminated board by an etching method or the like to form the inner layer circuit board 3. Obtained. Next, the two glass cloth base material prepreg sheets B and the copper foil 4 are superposed on the surface of the inner layer circuit board, respectively, and the whole is heated.
A four-layer printed wiring board was obtained by pressurizing and laminating. The dimensional stability, drilling workability, haloing resistance, and dielectric constant of this multilayer printed wiring board were measured and observed in the same manner as in Examples, and are shown in Table 1.

[0008]

[Table 1]

From Table 1, the four-layer printed wiring board substrate of the embodiment has substantially the same dimensional stability as that of the conventional example, and is improved in drill workability, haloing resistance, and low dielectric constant. I understand.

[0010]

As described above, the four-layer printed wiring board according to the present invention can be improved in drill workability, haloing resistance, and low dielectric constant with less loss of dimensional stability. There is a unique effect.

[Brief description of drawings]

FIG. 1 is an explanatory view illustrating a base material configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a base material configuration of an inner layer circuit board used in an example.

FIG. 3 is an explanatory diagram illustrating a base material configuration of a conventional example.

[Explanation of symbols]

1 ... Circuit pattern 2 ... Inner layer circuit board 3 ... Inner layer circuit board 4 ... Copper foil A ... Glass nonwoven fabric base material epoxy resin prepreg sheet A '... Glass nonwoven fabric base material epoxy resin curing Layer B: Glass cloth base material epoxy resin prepreg sheet B '... Glass cloth base material epoxy resin cured layer c: Glass cloth base material epoxy resin prepreg sheet

Claims (2)

[Claims] 1. A copper foil on the upper and lower surfaces of a double-sided copper-clad laminate having a composite structure in which a glass cloth-based prepreg sheet and a copper foil are respectively laminated and integrated on the upper and lower surfaces of a glass nonwoven fabric-based prepreg sheet. A circuit pattern is formed as an inner layer material, and a glass cloth base material prepreg sheet and a copper foil in which the amount of resin is increased with respect to each of the glass cloth base material prepreg sheets are laminated on the upper and lower surfaces of the inner layer material, respectively, and then the whole. A multilayer printed wiring board containing an inner layer circuit, which is obtained by heating and pressurizing and integrating the layers. 2. The glass cloth base material prepreg sheet having an increased amount of resin is a glass cloth having a nominal thickness of 0.18 mm to which 50 to 55% of an epoxy resin is adhered. Multi-layer printed wiring board.