JPH0555751A - Thin film multilayer circuit substrate - Google Patents

Abstract

PURPOSE:To provide a thin film multilayer circuit substrate which realizes small size and high mounting density and easily changes a capacitance value of capacitor. CONSTITUTION:Interlayer insulating layer 10 and wiring conductor layer 11 having via holes 12 are alternately laminated on an insulated substrate 1 to form a multilayer circuit substrate. At least one capacitor 7, which uses one of interlayer insulating layers 10 as a dielectric material 9 and the wiring conductor layers 11 almost in the same shape as the insulated substrates 1 in both sides as electrodes 8, 8a, is included. Moreover, the interlayer insulating layer which becomes a dielectric material 9 of the capacitor 7 is formed thicker than the other interlayer insulating layers 10 or formed by a material having a higher dielectric constant to acquire a capacitance value of a capacitor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film multilayer circuit board used for reducing the size and weight of electronic equipment.

[0002]

2. Description of the Related Art In recent years, thin film technology has been applied not only to semiconductors but also to substrates for high frequency circuits, substrates for computers, substrates for multichip modules, and the like. Compared with the conventional SMT technology (surface mounting technology: technology for soldering chip components to a printed circuit board), this thin film technology has a minimum possible line width of about 1/10, so that a circuit with higher density can be formed. .. FIG. 2 is a sectional view of a conventional thin film circuit board, which constitutes a circuit in which a capacitor and a resistor are formed.
In the figure, 1 is an alumina substrate (purity 99.5%), 2
Is a wiring conductor composed of a base Cr film (film thickness 50 n μm) for improving the adhesion to the alumina substrate 1 and a Cu film (film thickness 5 μm) thereon, and is formed by a sputtering method or a vapor deposition method and photolithography. Pattern is formed by the method. A thin film capacitor 3 is composed of an electrode 4 and a dielectric 5.
The electrode 4 is made of the same material as the wiring conductor 2 and the dielectric 5 is made of Ta ₂ O _5, for example. 6 is a resistor, NiCr, T
The wiring conductor 2 is made of aN or the like and is deposited by a sputtering method or a vapor deposition method to form a pattern by a photolithography method.

[0003]

When a capacitor is made from the thin film circuit board as described above, the required capacitance is formed by manipulating the area of the electrode or the film thickness of the insulating layer sandwiched between the electrodes. However, when it becomes necessary to change the capacity of one of the several capacitors on the circuit board thus manufactured, it takes a lot of time and labor to change the exposure mask.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a thin film multilayer circuit board which realizes a compact and high density circuit board and has a simple change of capacitor capacity.

[0005]

In order to achieve the above object, a thin film multilayer circuit board of the present invention is constructed by alternately laminating an interlayer insulating layer having a via hole and a wiring conductor layer on the insulating substrate. And includes at least one capacitor having one of the above-mentioned inter-layer insulation layers as a dielectric and electrodes having wiring conductor layers of substantially the same shape as the above-mentioned insulation substrate on both sides thereof,
In addition, the interlayer insulating layer serving as the dielectric of the capacitor has a smaller film thickness than other interlayer insulating layers or is made of a material having a higher dielectric constant than other interlayer insulating layers to secure the capacitor capacitance.

[0006]

With the above structure, the capacitance of the capacitor can be easily changed by adjusting the film thickness or the dielectric constant of the interlayer insulating layer while keeping the electrode of the capacitor constant and having substantially the same shape as the insulating substrate.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a thin film multilayer circuit board of the present invention. 1 is an alumina substrate, 7 is a capacitor composed of electrodes 8 and 8a and a dielectric 9, 10 is an interlayer insulating layer, 11 is a wiring conductor, and 12 is an interlayer insulating layer. Wiring conductor 1 sandwiching 10
It is a via hole that connects 1. The manufacture of the thin film multilayer circuit board configured as described above is as follows. First, a Cr film (film thickness 50 n is formed on the alumina substrate 1 by the sputtering method.
μm) and a Cu film (film thickness 1 μm) thereon. Next, a pattern is formed by photolithography to obtain the electrode 8. In this embodiment, the electrode 8 has substantially the same shape as the alumina substrate 1. Next, a Ta ₂ O ₅ film is formed to a thickness of 200 nm by a sputtering method.
A thick film is formed and a pattern including a via hole is formed by a photolithography method to form a dielectric 9. Similarly, the electrode 8a is formed in a shape slightly smaller than the dielectric 9 in order to prevent a short circuit by film formation and photolithography. Next, a photo-curable polyimide resin solution is formed by a spin coating method, and the polyimide film having the via holes 12 opened by pre-cure (80 ° C., 2H), exposure through a mask, development, and cure (400 ° C., 30 min). (20 μm) is formed to obtain the interlayer insulating layer 10. Cu is embedded in the via hole 12 by electrolytic or electroless plating. Further, the wiring conductors 11 and the interlayer insulating layers 10 are alternately stacked to obtain a thin film multilayer circuit. With the above configuration, changing the capacitor capacity is
It can be easily performed by adjusting the film thickness or the dielectric constant of the dielectric 9. The alumina substrate 1 may be glass or a metal-based insulating substrate. The dielectric 9 is made of SiO ₂ , BaTiO ₃
And so on. The interlayer insulating layer 10 may be SiO ₂ or the like. Also, capacitors may be formed in multiple layers and connected in series or in parallel.

[0008]

As is apparent from the above description, the thin film multilayer circuit board of the present invention realizes a small size and high density of the circuit board, the change of the capacitor capacity is easy, and the large capacity capacitor is easy to make. .. Further, the capacitance of the capacitor is changed by changing the film thickness or the dielectric constant of the dielectric, and since the photomask is not changed, the design change can be promptly dealt with.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a thin film multilayer circuit board of the present invention.

FIG. 2 is a sectional view of a conventional thin film multilayer circuit board.

[Explanation of symbols]

 1 Alumina Substrate (Insulation Substrate) 7 Capacitor 8, 8a Electrode 9 Dielectric 10 Interlayer Insulation Layer 11 Wiring Conductor (Wiring Conductor Layer) 12 Via Hole

Claims (2)

[Claims] 1. An interlayer insulating layer having a via hole and a wiring conductor layer are alternately laminated to form a multilayer structure,
It includes at least one capacitor having one of the above-mentioned interlayer insulating layers as a dielectric and a wiring conductor layer of substantially the same shape as the above-mentioned insulating substrate on both sides thereof as an electrode, and the other interlayer insulating layer serving as a dielectric of the above capacitor is not included. Thin-film multi-layer circuit board that is thinner than the inter-layer insulating layer. 2. An interlayer insulating layer having a via hole and a wiring conductor layer are alternately laminated in multiple layers on an insulating substrate,
It includes at least one capacitor having one of the above-mentioned interlayer insulating layers as a dielectric and a wiring conductor layer of substantially the same shape as the above-mentioned insulating substrate on both sides thereof as an electrode, and the other interlayer insulating layer serving as a dielectric of the above capacitor is not included. Thin-film multilayer circuit board made of a material having a higher dielectric constant than the interlayer insulating layer of.