JPH0424985A - Manufacture of electric laminate - Google Patents

Abstract

PURPOSE:To realize free design of permitivity, by stacking a plurality of prepreg sheets of different permitivity, stacking metal foils on the sheets, and laminating them in a unified body. CONSTITUTION:For example, four prepreg sheets 1a of one sort and four prepreg sheets 1b of other sort are alternately stacked, and thereon metal foils 2 are stacked. These sheets are heated with pressure, and molded in a laminated body, thereby obtaining a laminate for electric use. When glass cloth substratum fluororesin prepreg (permitivity 2.7) is used as the four prepreg sheets 1a, and glass cloth substratum epoxy resin prepreg (permitivity 4.8) is used as the four prepreg sheets 1b, the following laminate is manufactured; the permitivity at the laminated part of the laminate for electric use is equal to about (2.7X4+4.8X4)divided by 8=3.7-3.8. Hence an arbitrary value can be set by combining various kinds of prepreg sheets of different permitivity.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for manufacturing an electrical laminate that is processed into a printed wiring board.

[Conventional technology]

Printed wiring boards used in electrical equipment, electronic equipment, etc.
It is created by processing electrical laminates covered with metal foil. That is, an electrical laminate can be manufactured by stacking a plurality of prepregs, further stacking a metal foil such as copper foil on one or both sides of the prepreg, and then heating and pressurizing the prepreg to form a laminate. By etching the metal foil of this electrical laminate to create a circuit pattern, it can be finished into a printed wiring board. For such printed wiring boards, there has recently been an increasing demand for fine patterns in which circuits are formed in minute and dense patterns.However, in fine patterns, the spacing between circuits is narrower, so the impedance between the patterns is lower. This causes problems such as noise interference. If the dielectric constant of the electrical laminate from which the printed wiring board is made is low, the impedance will be low and noise disturbances will occur significantly, so the use of electrical laminates with a low dielectric constant is being considered. Here, in an electrical laminate, the dielectric constant is controlled by the base material and resin that make up the laminate, that is, the dielectric constant is controlled by the prepreg formed by impregnating the base material with resin. It turns out. For example, in various prepregs, the dielectric constant (ε) is ・Paper base material 7ヱ/-L resin prepreg ・・・4.3・
Paper-based epoxy resin prepreg...4.3.
Epoxy resin prepreg for lath cloth base material...4.8・〃Polyimide prepreg for lath cloth base material...4.5・〃Prepreg for polyphenylene oxy resin base material for cloth cloth...3.5・〃
Fluororesin prepreg for lath cloth base material: 2.7, and electrical laminates made using these prepregs have a specific dielectric constant for each prepreg. Therefore, when forming circuits with fine patterns, it is possible to reduce the occurrence of noise disturbances between circuits by using electrical laminates made using prepreg with a low dielectric constant. . However, since prepregs with a low dielectric constant are generally expensive, for example, when it is necessary to form a circuit with a particularly high fine pattern, a lath cloth base material 77 base resin prepreg with a dielectric constant of 2.7 is used. When forming a circuit with a medium 7-fin pattern, a glass cloth base polyphenylene oxide prepreg with a dielectric constant of 3.5 is used, and when the degree of fine pattern is not very high, other prepregs are used. As such, the prepreg to be used is selected depending on the degree of fine pattern.

[Problem to be solved by the invention]

However, since the dielectric constant of each prepreg is a specific value, the dielectric constant of electrical laminates made using prepreg can only be obtained with a specific value depending on the prepreg, and fine patterns cannot be obtained. There has been a problem in that the dielectric constant of the electrical laminate cannot be freely designed depending on the degree of the problem. The present invention has been made in view of the above points, and it is an object of the present invention to provide a method for manufacturing an electrical laminate that allows for free design of the dielectric constant of the electrical laminate.

[! Means to solve problem I】

The method for manufacturing an electrical laminate according to the present invention is characterized in that a plurality of prepregs having different dielectric constants are stacked, a metal foil is further stacked on top of the prepregs, and the stacks are integrated. Prepreg is created by impregnating a base material such as paper or glass cloth with a face of various thermosetting resins (or thermoplastic resins in some cases) and drying it. The ratio is set to a predetermined value depending on the base material, the type of resin, etc. Then, by layering multiple sheets of prepreg, layering metal foil such as copper foil on one or both sides, and forming the laminated layer by heating and pressing, an electrical laminate with metal foil on one or both sides is created. Obtainable. Here, in the present invention, a plurality of prepregs having different dielectric constants are used in combination,
For example, as shown in FIG. 1, a certain type of prepreg 1a
An electrical laminate can be obtained by alternately stacking four sheets of prepreg 1b and four sheets of other types of prepreg 1b, overlaying metal foil 2 on top of this, heating and pressurizing it to form a laminate.
As shown in the upper part of the figure, four sheets of prepreg 1& of one type are alternately stacked two at a time and four sheets of prepreg 1b of another type are stacked two at a time, and then metal foil 2 is layered over this and heated and pressed. An electrical laminate can be obtained by lamination molding. Of course, the arrangement of the prepregs 1a and 1b is not limited to these, and may be a random arrangement. In addition, not only two types of prepreg may be used in this way, but a combination of three or more types may be used. For example, if a fluororesin prepreg with a lath fabric base is used as the prepreg, the dielectric constant (ε) of the laminate portion of the electrical laminate will be 2.7, which is the same as the dielectric constant of this prepreg, and the total If epoxy resin prepreg is used as a base cloth cloth, the dielectric constant of the laminate part of the electrical laminate will be 4.8, which is the same as the dielectric constant of this prepreg, but the 4 sheets in Figure #IJ1 and Figure 2 prepreg 1a
When producing a conventional laminate using lath cloth base material fluororesin prepreg as 1-f lightning resin prepreg and glass cloth base epoxy resin prepreg as four prepregs 1b, respectively,
The dielectric constant of the laminate portion of this electrical laminate is approximately (2,7
X4+4.8X4)÷8=3.7 to 3.8. In addition, out of the total of 8 prepregs, if 6 sheets of lath cloth-based 7-carbon resin prepreg and 2 sheets of lath cloth-based epoxy resin prepreg are used, the dielectric constant of the laminate part of the electrical laminate is Approximately (2.7x6+4.8x2)÷8=3.2~
It becomes 3.3. Therefore, the dielectric constant of the laminate part of the electrical laminate can be set to any value by selecting which type and how many prepregs are used in combination among various types of prepregs with different dielectric constants, and forming circuits. This increases the degree of freedom in designing the dielectric constant according to the degree of the seven-fin pattern.

【Example】

The invention will now be illustrated by examples. Example 1 The amount of resin after drying was 5 on a plus cloth with a thickness of 0.15 m111.
It was impregnated with epoxy resin to a concentration of 0% and dried to obtain a lath cloth base epoxy resin prepreg having a dielectric constant of 4.8. In addition, a glass cloth with a thickness of 0.15 fflL11 is impregnated with polyphenylene oxide (PPO) so that the amount of resin after drying is 50%, and by drying it, a glass cloth base polyphenylene oxide prepreg with a dielectric constant of 3.5 is obtained. Obtained. Next, in the arrangement shown in FIG. 1, four sheets of lath cloth base epoxy resin prepreg and four sheets of gamma lath cloth base polyphenylene oxide prepreg are stacked, and a thickness of 0.5 mm is added on both sides.
035. Layer the copper foil of 30 kg/cm
2. An electrical laminate having a thickness of 1°611I11 was obtained by heating and pressing under the conditions of 180° C. and 90 minutes to form a laminated sheet. The dielectric constant of this electrical laminate was about 4.1. ((External Example 1) An electrical laminate with a thickness of 1.6 mm was obtained by using only 8 sheets of the lath fabric base epoxy resin prepreg and laminating in the same manner. The dielectric constant of the plate was 4.8.
An electrical laminate having a thickness of 1.6 mm was obtained by using 8 sheets of prepreg and carrying out lamination molding in the same manner. The dielectric constant of this electrical laminate was 3.5. Example 2 A 0.15 mm thick glass cloth was impregnated with polyimide so that the amount of resin after drying was 50%, and dried to obtain a glass cloth base polyimide prepreg having a dielectric constant of 4.5. Next, in the arrangement shown in FIG. 2, the four lath cloth-based polyphenylene oxide prepregs obtained in Example 1 and the four lath cloth-based polyimide prepregs were stacked together, and the rest was laminated and molded in the same manner. An electrical laminate having a thickness of 1.6 mm was obtained. The dielectric constant of this electrical laminate was approximately 4.0. [Effects of the Invention] As described above, in the present invention, a plurality of sheets of prepreg with different dielectric constants are stacked together, a metal foil is further stacked on top of this, and this is laminated and integrated. The dielectric constant of the electrical laminate can be set to any value depending on which type of prepreg is used in combination, and the dielectric constant can be adjusted to suit the fine pattern of circuit formation. This increases the degree of freedom in design.

[Brief explanation of drawings]

1 and 2 are schematic exploded views showing the structure of laminated molding, 1 at 1 b is a prepreg, and 2 is a metal foil.

Claims (1)

[Claims] (1) A method for producing an electrical laminate, which comprises stacking a plurality of prepregs having different dielectric constants, further stacking a metal foil thereon, and integrating the stacked sheets.