JP3854517B2 - Membrane capacitor and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a film capacitor, a manufacturing method therefor, and a circuit board having the film capacitor. More specifically, the present invention relates to miniaturization of components in response to demands for miniaturization and weight reduction of electric / electronic devices. The present invention relates to a film capacitor corresponding to the above, a manufacturing method thereof, and a circuit board having the same.
[0002]
[Prior art and its problems]
Due to the demand for further miniaturization and weight reduction of electric and electronic devices, the density of wiring is increasing year by year. For this reason, the size of components such as capacitors and resistors mounted on a circuit board has also been reduced.
[0003]
However, in order to mount components, a land for mounting is required, which is an impediment to improving the wiring density of the circuit board. Further, the miniaturization of parts requires further improvement in alignment accuracy, which is disadvantageous in productivity.
[0004]
[Means for Solving the Problems]
The electrodeposition method is a method capable of forming a film on all current-carrying portions, and can be electrodeposited for forming a surface protective layer, and is being studied as a method for forming a surface protective layer on a circuit board.
[0005]
Therefore, in the present invention, a concave portion or a through hole is provided at a predetermined location of the insulating base material, a conductor layer is formed on the inner periphery of the concave portion or the through hole, and a thin dielectric layer is formed on the conductor layer. A film-like capacitor can be formed by forming a conductor layer which is a counter electrode of the capacitor on the dielectric layer.
[0006]
At this time, since the electrodeposition technique is used when forming the dielectric layer, the capacitance of the formed film capacitor can be arbitrarily controlled by arbitrarily controlling the film thickness of the dielectric by electrodeposition according to the electrodeposition conditions. It becomes possible to set to.
[0007]
In addition, when the dielectric is formed by a method such as laminating, if the concave portion or the through-hole is fine, embedding becomes difficult and a defect is caused. On the other hand, a method of forming a dielectric layer with a varnish is also conceivable. However, as with a laminate, embedding is difficult for miniaturization, and the material is expensive, which is disadvantageous in terms of cost.
[0008]
It is also possible to set the capacitance of the capacitor by increasing the surface area and roughening the surface of the conductor layer and dielectric layer formed on the inner periphery of the recess by appropriate means, and increasing the facing area. It is.
[0009]
Furthermore, since the capacitor formed by the above method is formed as a part of the wiring, the size can be made smaller than that of the conventional capacitor, and since it has a structure embedded in the substrate, it can be reduced in the thickness direction. Therefore, for example, it can be applied to an inner layer capacitor in a multilayer circuit board.
[0010]
When a flexible substrate is applied as a base material, a flexible circuit substrate having a capacitor can be formed, and further folding can be achieved by providing lighter weight, smaller size, and flexibility.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a manufacturing process diagram of a film capacitor according to an embodiment of the present invention. First, as shown in Fig. 1 (1), dry etching such as laser, plasma, reactive ion etching, etc., chemical wet etching such as resin etching, or drill or punch on the upper surface of an appropriate insulating substrate 1 The concave portion 2 is formed by mechanical processing such as.
[0012]
Next, as shown in FIG. 2 (2), the circuit wiring pattern 3 as a conductor layer is formed using an additive method, and at the same time, the conductor layer 4 is also formed on the inner periphery of the recess 2. Alternatively, a conductor layer is formed on the entire upper surface of the substrate including the recess 2, and the circuit wiring pattern 3 and the conductor layer 4 are formed on the inner periphery of the recess by a subtractive method. Thereafter, the surface of the conductor layer is roughened by a mechanical method such as blasting or a chemical method such as soft etching, if necessary.
[0013]
Next, a thin dielectric layer 5 is formed on the conductor layer 4 formed in the recess 2 by electrodeposition as shown in FIG. Thereafter, if necessary, the surface of the dielectric layer 5 is roughened by a mechanical method such as blasting or a chemical method such as soft resin etching.
[0014]
Further, a film capacitor is obtained by forming the conductor layer 6 using a method such as additive as shown in FIG.
[0015]
FIG. 2 is a manufacturing process diagram of a film capacitor according to another embodiment of the present invention. First, dry etching such as laser, plasma, reactive ion etching, etc., chemical wet etching, or mechanical processing such as drilling or punching is performed on an appropriate insulating substrate 7 as shown in FIG. Through holes 8 are formed by the above.
[0016]
Next, as shown in FIG. 2 (2), a circuit wiring pattern 9 as a conductor layer is formed by using an additive method, and at the same time, a conductor layer 10 is also formed on the inner periphery of the through hole 8. Alternatively, a conductor layer is formed on the entire upper surface of the substrate including the through hole 8, and the conductor layer 10 is formed on the inner periphery of the circuit wiring pattern 9 and the through hole 8 by a subtractive method. Thereafter, the surface of the conductor layer is roughened by a mechanical method such as blasting or a chemical method such as soft etching, if necessary.
[0017]
Next, a dielectric layer 11 is formed on the conductor layer 10 formed in the through hole by electrodeposition as shown in FIG. Thereafter, the surface of the dielectric layer is roughened by a mechanical method such as blasting or a chemical method such as soft resin etching, if necessary.
[0018]
Further, as shown in FIG. 4 (4), a film capacitor is obtained by forming the conductor layer 12 using a technique such as additive.
[0019]
In these embodiments, after forming a wiring by a subtractive method or a semi-additive method using a base material that already has a conductor layer on one side or both sides as a base material, a recess or a through hole is formed, and then the inner periphery of the recess or the through hole is formed. Further, a conductor layer, a dielectric layer, and an opposing conductor layer may be formed.
[0020]
【The invention's effect】
According to the present invention, since the electrodeposition technique is used, it is possible to form a dielectric layer without defects in a conductor layer formed in a fine depression or through hole.
[0021]
Furthermore, the capacitance of the film capacitor can be arbitrarily set by controlling the electrodeposition conditions.
[0022]
Since the film capacitor formed by the above method is formed as a part of the wiring, the size can be made smaller than that of the conventional capacitor, and since it has a structure embedded in the substrate, it has a thickness direction. Since it can be reduced, for example, it can be applied to an inner layer capacitor in a multilayer circuit board. As a result, it contributes to the reduction in size and weight of the product.
[0023]
Furthermore, when a flexible substrate is applied as a base material, a flexible circuit substrate having a capacitor can be formed, and further light weight, downsizing, and flexible mounting can be achieved. As a result, it contributes to the reduction in size and weight of the product.
[Brief description of the drawings]
FIG. 1 is a manufacturing process diagram of a film capacitor according to an embodiment of the present invention.
FIG. 2 is a manufacturing process diagram of a film capacitor according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Insulating base material 2 Recessed part 3 Circuit wiring pattern 4 Conductive layer 5 of recessed part inner periphery Dielectric layer 6 Opposing conductor layer 7 formed on the dielectric layer Insulating base material 8 Through hole 9 Circuit wiring pattern 10 In through hole Circumferential conductor layer 11 Dielectric layer 12 Opposing conductor layer formed on the dielectric layer

Claims (4)

A recess or a through hole is provided at a predetermined location of the insulating base material, a conductor layer is provided on the inner periphery of the recess or the through hole, and a dielectric layer is provided on the conductor layer by electrodeposition means. A film capacitor in which a counter electrode is provided and a surface area of the capacitor is increased by roughening the surfaces of the conductor layer and the dielectric layer. A recess or a through hole is formed at a predetermined location of the insulating substrate, a conductor layer is formed on the inner periphery of the recess or the through hole, a dielectric layer is formed on the conductor layer by electrodeposition means, and the dielectric A manufacturing method of a film capacitor in which a conductor layer which is a counter electrode in a capacitor is formed on a body layer, and the opposing area of the capacitor is increased by roughening the surfaces of the conductor layer and the dielectric layer. The method for manufacturing a film capacitor according to claim 2, wherein the capacitance is arbitrarily set by changing the conditions of the electrodeposition technique. A circuit board on which a film-like capacitor constituted by any one of the preceding claims is integrally formed.

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