JPH03201593A - Multilayer wiring circuit module - Google Patents

Abstract

PURPOSE:To form a film having excellent heat resistance and high permittivity by providing a dielectric film formed by kneading fine powder material having high permittivity and organic polymer insulating material having heat resistance in a sheet state, and electrodes formed at least on one side surface of the ferroelectric film. CONSTITUTION:Through holes 2 are formed previously through a board 1. Both side surfaces of the board 1 are printed with conductive paste, and dried to be formed with an upper electrode 4 of a capacitor and a wiring layer 5. Similarly, a unit wiring sheet 8 printed with a lower electrode 7 of the capacitor is formed on a thermoplastic material 6, fine powder material having high permittivity and organic polymer insulating material having heat resistance are kneaded, and disposed on an inner layer in the form of a dielectric film 9. Then, a plurality of the sheets 8 and the films 9 are laminated, and thermally press-bonded thus producing a multilayer wiring circuit module containing a capacitor formed of the electrodes 4, 7 and the film 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention particularly relates to a multilayer wiring circuit module having a built-in capacitor element in an inner layer.

(Conventional technology) In recent years, electronic devices have rapidly become smaller and more multifunctional, and as a result, components have become smaller and thinner, and circuits have become more complex, making it difficult to wire them on the same plane. It has become to.

For this reason, various types of wiring multilayering, such as thick film printing, green sheet multilayering, through-hole multilayering, etc., have been carried out, and each has come into practical use.

By the way, if components are built into the board and wiring is formed using multilayer technology, the circuit module can be further miniaturized. Recently, as such a circuit module, a multilayer printed wiring board that is integrally formed by stacking a plurality of unit wiring sheets each consisting of a thermoplastic substrate and a conductor wiring pattern formed on one or both sides of this substrate, is being used. A circuit in which electrodes are formed and arranged has been proposed.

FIGS. 1A to 1C are cross-sectional views showing an example of a method for manufacturing a multilayer wiring circuit module in the order of steps.

■First, a thermoplastic resin insulating substrate 1 formed into a sheet shape
Prepare. Here, a through hole 2 is provided in advance in the substrate 1, and 3 in the figure is a land on the surface of the substrate (as shown in FIG. 1(A)).

(2) Next, a conductive paste is printed on both sides of the insulating substrate 1 and dried to form an upper electrode 4 and a wiring layer 5 of a capacitor, which will be described later. Similarly, a unit wiring sheet 8 on which the lower electrode 7 of a capacitor was printed was formed on a thermoplastic substrate 6, and a dielectric film 9 was placed on the inner layer (as shown in FIG. 1(B)).

Although the wiring layer is formed on both sides of the insulating substrate and the thermoplastic base material 5, it may be formed on both sides of the dielectric film. Alternatively, holes may be provided in the dielectric film in advance and processed so that the dielectric sheets can be sandwiched and connected to each other. Next, a plurality of unit wiring sheets 8 and dielectric films 9 obtained as described above are laminated.

■Next, in this state, heat and pressure bonding is carried out using a heat press,
A multilayer wiring circuit module having a built-in capacitor IO is manufactured (as shown in FIG. 1(C)).

However, according to the conventional multilayer wiring circuit module, the dielectric constant of the dielectric film is 3 to 5 when viewed from the characteristics of the capacitor. The capacitance is relatively small and it is difficult to form large capacitance capacitors.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and it enables the formation of a film with better heat resistance and higher dielectric constant than conventional ones, and is capable of forming a multilayer capacitor with a large capacity. The purpose is to provide a wired circuit module.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention includes a thermoplastic insulating substrate and a plurality of thermoplastic insulating substrates that are integrally provided on at least one side of the insulating substrate and have a wiring pattern formed on the main surface. A unit wiring sheet, and a dielectric film which is provided between the insulating substrate and the sheets or between the sheets and is formed into a sheet by kneading a fine powder material having a high dielectric constant and an organic polymer insulating material having heat resistance. , and an electrode formed on at least one side of the ferroelectric film.

In the present invention, the material of the insulating substrate includes, for example, polyvinyl chloride, polystyrene, saturated polyester resin, polyethylene, polypropylene, polycarbonate,
Examples include thermoplastic resins such as polyphenylene oxide, polysulfone, polyphenylene sulfide, polyacetal, and polyamide.

In the present invention, the wiring pattern formed on the main surface of the unit wiring sheet is formed by printing and drying a conductive paste on the insulating substrate. A mixture prepared by kneading a thermoplastic resin as a binder with metal powder is used, and a solvent is appropriately added if necessary. here,
As the metal powder, any of silver, copper, nickel, platinum, aluminum, etc. may be used, but copper and silver are preferable in terms of conductivity and economy.

In the present invention, examples of the fine powder material having a high dielectric constant include inorganic materials such as barium titanate, strontium titanate, titanium oxide, tantalum oxide, and aluminum oxide. The particle size of these materials is preferably approximately 0.1 to 5 μm. The mixing ratio of the dielectric constant material to the organic polymer insulating material described below varies depending on the materials used, but is in the range of 0.5 to 5:5 to 9.5 by weight. Therefore, in order to increase the dielectric constant of the dielectric film, the proportion of the inorganic material etc. may be increased.

In the present invention, examples of heat-resistant organic polymer insulating materials include polyphenylene sulfide, polybutylene terephthalate, polyethylene terephthalate, polycarbonate resin, and the like.

Next, a method for manufacturing a multilayer wiring circuit module according to the present invention will be explained.

■First, a thermoplastic resin insulating substrate 1 formed into a sheet shape
Prepare. Here, a through hole 2 is provided in advance in the substrate 1, and 3 in the figure is a land on the surface of the substrate (as shown in FIG. 1(A)).

(2) Next, a conductive base is printed on both sides of the insulating substrate 1 and dried to form an upper electrode 4 and a wiring layer 5 of a capacitor, which will be described later. Similarly, a unit wiring sheet 8 on which a lower electrode 7 of a capacitor described later is printed is formed on a thermoplastic base material 6,
A dielectric film 9 made of a sheet formed by kneading a fine powder material having a high dielectric constant and an organic polymer insulating material having heat resistance is disposed in the inner layer (as shown in FIG. 1(B)). Although the above wiring layer is formed on both sides of the insulating substrate 1 and the thermoplastic base material 5, it may be formed on both sides of the dielectric film 9. Alternatively, holes may be provided in the dielectric film 9 in advance and processed so that the dielectric sheets can be sandwiched and connected to each other. Next, the pieces obtained as described above are heat-pressed by a hot press.

(2) Next, a plurality of unit wiring sheets 8 and dielectric films 9 are laminated and bonded under heat using a heat press, and a dielectric film 10. A multilayer wiring circuit module containing a built-in capacitor 1O composed of an upper electrode 4 and a lower electrode 7 is manufactured (as shown in FIG. 1(C)). The temperature, pressure, pressing time, etc. of the above heat press vary depending on the material used.
The conditions are selected as appropriate. Note that by the above-described integration, the final conductive pattern including the electrical connections within the through holes is formed at the same time. Furthermore, since the conductor paste is made of thermoplastic resin, the conductor patterns on the upper and lower unit wiring sheets are thermally fused together by heat-pressing, thereby ensuring electrical contact. Furthermore, if a base material with a higher thermal deformation temperature than that of the unit wiring sheet is used for the ferroelectric film for capacitors, the ferroelectric film for capacitors will not undergo thermal deformation during hot press bonding and will maintain its original dielectric state. Characteristics can be maintained.

In the module obtained in this way, the capacitance C of the capacitor 10 is C-ε-S, where d is the thickness of the dielectric film, and S is the contact area between the upper and lower electrodes.
/d (where ε indicates the dielectric constant of the organic film). Here, since ε is usually 2 to 5, in order to increase C, the thickness d of the film must be made as thin as possible to form a multilayer film, or the area S must be increased. However, inorganic dielectric films have a much higher dielectric constant than organic dielectric films, about -5 to 500. Therefore, it is possible to form a large capacitance capacitor under the same d and S conditions as compared to a conventional capacitor using a dielectric film made only of organic materials.

(Example) Hereinafter, an example of the present invention will be described along with a manufacturing method.

First, a thermoplastic insulating substrate with a thickness of 100 μm and an outer diameter of 5
Prepare a polycarbonate sheet of 0 to 60 ma+,
A through hole of 0.5a+mφ was formed at a predetermined position on the substrate. Next, a conductive paste prepared by kneading silver powder and a solvent with the following composition was printed on one main surface of the substrate using polyvinyl chloride as a binder.

1. Vinyl chloride-vinyl acetate copolymer (vinyl acetate ratio 20%) 10 parts by weight 2. Silver powder (particle size 3 μm) 90 parts by weight 3. Solvent (mixed solvent of cyclohexane and butylcarpitol) 90 parts by weight Next, 80 parts by weight ℃ for 20 minutes to remove the solvent of the printed conductor paste, print the same conductor paste on the other side of the substrate, and pattern it to a size of 5 x 5 l1m.

Upper electrodes of 10×10a+m and 20×20 were formed.

Next, as a dielectric film, a film with a thickness of 25 mm with through holes was formed.
A PPS (polyphenylene sulfide, trade name KPS, manufactured by Kenbetsu Kagaku Co., Ltd.) film of μm was prepared. Subsequently, the above-mentioned conductive paste is applied to the substrate for 40 minutes.
A lower electrode of 850a+m was formed by printing.

Next, three unit wiring sheets were stacked as shown in Figure 1 (B), and a heater temperature of 150°C was set using a tabletop heat press.
Resin 20K g/0m2. After thermocompression bonding was carried out with a holding time of 5 minutes, it was immediately cooled and taken out.

Thus, the multilayer wiring circuit module manufactured as described above has a dielectric film 9. It has a built-in capacitor IO consisting of an upper electrode 4 and a lower electrode 7, and the dielectric film 9 has not only an organic material but also a very high dielectric constant (ε-5 to 50) compared to the dielectric constant of the organic material. Because it has a structure that also includes inorganic materials, it is possible to form a large capacity capacitor under the same d and S conditions compared to conventional dielectric film capacitors made only of organic materials, making it possible to create large capacitance and small capacitors at low cost. can be obtained. Furthermore, by using a temperature compensation type (negative slope temperature characteristics such as CH, RH, PR, etc.) for the dielectric film, temperature compensation of the circuit can be achieved. In other words, capacitors with various temperatures can be realized. Furthermore, since integral formation and multilayering are performed by heat-press bonding, the overall thickness can be made extremely thin, and complicated processes such as TH plating associated with interlayer wiring can be omitted.

On the upper surface of the obtained substrate, the lower electrode of the capacitor is exposed through a through hole in the dielectric film by pressing, making it possible to maintain an electrical constant of 81°. Table 1 below is
The results of measuring the capacitance of three patterns using an LCR meter manufactured by YHP are shown (however, the measurement frequency is 1 μHz).

Table 1 also shows that the total thickness was about 200 μm, and the reliability of adhesion including through-holes was good, with no foreign products observed at 0° C. to +GO° C. for 200 cycles.

[Effects of the Invention] As detailed above, according to the present invention, the conventional organic material II
Compared to capacitors using only ferroelectric film,
It is possible to form a film with good heat resistance and a high dielectric constant, thereby providing a multilayer wiring circuit module that can form a large-capacity, small-sized capacitor.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a multilayer wiring circuit module in the order of manufacturing steps. 1... Thermoplastic insulating substrate, 2... Through hole, 4...
... Upper electrode, 5... Wiring layer, 6... Thermoplastic base material, 7... Lower electrode, 8... Unit wiring sheet, 9...
・Ferroelectric film, lO...capacitor. Representative of dispatcher Patent attorney Takehiko Suzue 531-

Claims (1)

[Claims] A thermoplastic insulating substrate, a plurality of unit wiring sheets integrally provided on at least one side of the insulating substrate and having a wiring pattern formed on the main surface, and a plurality of unit wiring sheets provided between the insulating substrate and the sheets or between the sheets, and having a high A ferroelectric film formed into a sheet by kneading a fine powder material having a dielectric constant and an organic polymer insulating material having heat resistance, and an electrode formed on at least one side of the ferroelectric film. A multilayer wiring circuit module featuring: