JPH05347227A - Laminated thin film capacitor - Google Patents

Abstract

PURPOSE:To increase the surface package density by a method wherein an aperture part in larger diameter than that of a via hole is formed in the inner electrode not to be connected to at least one conductor while an insulating part is provided between a conductor and the inner electrode not to be connected passing through the aperture part so that the polarities of the opposite inner electrodes may be differentiated. CONSTITUTION:The diameter of an aperture part 1a formed in inner electrodes is larger than that of a conductor 2a. On the other hand, the inner electrode is connected to a vertical conductor 2b passing through the right-hand via hole but not connected to another vertical conductor 2b passing through the left-hand via hole while the space between the via holes and the inner electrodes is filled up with a dielectric 3. Besides, three pairs of inner electrodes holding the dielectric 3 layers are arranged on an RC substrate 4 alternately connecting either one of the vertical conductors 2a, 2b while the topmost step of the inner electrodes is covered with an overcoat 5. Furthermore, the conductor pads 6 comprising outer electrodes are connected to the vertical conductors 2a, 2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer thin film capacitor using ceramics, and more specifically to a multilayer thin film capacitor for miniaturization.

[0002]

2. Description of the Related Art In recent years, electronic devices have been further miniaturized due to improvements in electronic circuit technology. This tendency is particularly remarkable in the field of semiconductor elements, but electronic components such as capacitors used together with semiconductor elements are relatively behind, and miniaturization thereof is an urgent issue.

Under these circumstances, multilayer thin film capacitors have been attracting attention because they have excellent characteristics such as small size and high reliability. As an example of a multilayer thin film capacitor using a ceramic material, (1) JP-A-4-371 is available.
No. 05 and (2) JP-A-4-34913.

[0004]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention In the laminated thin film capacitor having the structure disclosed in the above-mentioned document (1),
There is a drawback in that the area of the external electrode portion and the portion of the internal electrode extending from the internal electrode to the external electrode is larger than the area of the internal electrode portion that contributes to the capacitance of the capacitor. Further, according to the structure of the multilayer thin film capacitor disclosed in the above (2) document, the external electrode tends to be large, and further,
Since the external electrodes have to be formed so as to cover the upper and lower sides, there is a drawback that they are not suitable for surface mounting.

In view of these problems, it is an object of the present invention to reduce the size of a capacitor by making electrical connections between internal electrodes and from the internal electrodes to external electrodes within a capacitor element.

[0006]

The present invention provides a multilayer thin film capacitor having a plurality of parallel internal electrodes sandwiching a dielectric and external electrodes connected to the internal electrodes.
A via hole is provided in the dielectric body through which a conductor for making a necessary electrical connection between the internal electrodes is provided, and a diameter larger than the diameter of the via hole is provided in the internal electrode where connection to at least one of the conductors is not desired. An opening is provided, an insulating portion made of the above-mentioned dielectric is provided between the internal electrode and a conductor which is not desired to be connected through the opening, and the opposing internal electrodes are internal electrodes having different polarities. A multilayer thin film capacitor is provided.

With such a structure, it is possible to obtain a laminated thin film capacitor having a maximum capacitor capacity with a minimum surface mounting area.

The multilayer thin film capacitor of the present invention can be prepared by using a green sheet of a glass-based, composite perovskite or lead-based high temperature or low temperature fired ceramic material as a dielectric on an RC substrate.

First, when a conductor such as W or Mo, or a dielectric material that can be fired at a low temperature is used on a planar RC substrate, a paste of a conductor material such as Ag-based or Cu-based is used inside the laminated thin-film capacitor. Printing is performed by a method such as screen printing according to the electrode pattern. A green sheet of ceramic material is placed on top of it, and a via hole of appropriate size is formed by a punching die or punching machine. The via hole thus formed is filled with a conductive material. Further, an electrode pattern is printed on the green sheet. After repeating these steps as many times as desired, for example, 80 to 150 ° C., 50 to 250 kg
Thermocompression bonding under the condition of / cm ² . The number of laminated internal electrodes is not particularly limited, but is preferably about 4 to more than 10 layers. In this embodiment, there are 6 layers.

After that, under appropriate temperature and atmosphere conditions,
Bake. An overcoat can be applied on the uppermost internal electrode to protect the internal electrode.

In order to efficiently manufacture a laminated thin film capacitor, for example, a plurality of laminated thin film capacitor patterns are formed on a substrate having a length and a width of about 50 to 100 mm, respectively,
After completion of the steps such as firing, the substrate can be cut along the cut lines to obtain individual laminated thin film capacitors. Therefore, several tens to several hundreds of laminated thin film capacitors can be manufactured at one time.

Further, the individual laminated thin film capacitors manufactured in this manner can be subjected to side surface insulation treatment and the like. Also, in order to eliminate the need for such insulation treatment,
It is also possible to print the conductor in a pattern such that the inner electrode conductor does not reach the edge portion of each laminated thin film capacitor.

[0013]

EXAMPLES The present invention will be described more specifically by way of examples with reference to FIGS. 1 to 4.

FIG. 1 shows an example of an electrical connection diagram of the multilayer thin film capacitor according to the present invention. The conductors forming the internal electrodes 1 are alternately connected by vertical internal wirings 2a and 2b passing through the via holes to form two sets of internal electrodes. The space between the internal electrodes is filled with the dielectric 3.

FIG. 2 shows an example of a plane cross section taken along the line AA of the internal electrode 1 of the multilayer thin film capacitor having the connection shown in FIG. In FIG. 2, an opening 1a is formed in the internal electrode. This opening 1a has a larger diameter than the conductor 2a. Thus, the internal electrode conductor is connected to the vertical conductor 2b passing through the via hole on the right side,
No internal electrode conductor is connected to the vertical conductor 2a passing through the left via hole, and the space between the via hole and the internal electrode is filled with the dielectric 3. In addition, the internal electrode conductor 1
The pattern is slightly smaller than the external size of each multilayer thin film capacitor, and the dielectric 3 ensures the electrical insulation between the internal conductor and the outside of the capacitor.

An example of a laminated thin film capacitor having the connection of FIG. 1 is shown in FIG. 3 as a vertical sectional view. On the RC substrate 4, a pair of three sets of internal electrodes 1 are respectively arranged across the layer of the dielectric 3. 2 for each internal electrode
Vertical conductors 2a, 2b formed in a certain via hole
Are alternately connected to one of. An overcoat 5 is applied on the uppermost internal electrode. Further, conductor pads 6 forming external electrodes are connected to the vertical conductors 2a and 2b. The conductor pad 6 can be provided on the bottom surface and / or the side surface of the multilayer thin film capacitor. The conductor pad 6 ensures electrical and mechanical connection with an external circuit when the capacitor is mounted.

The multilayer thin film capacitor according to the present invention is shown in FIG.
As shown in Fig. 2, a large-sized laminated substrate-shaped fired body is prepared, a large number of laminated thin film capacitor units 7 are formed on the above substrate, and then cut along vertical and horizontal cut lines 8. Can be used as individual capacitors. As a result, manufacturing efficiency can be increased and cost can be reduced.

[0018]

According to the multilayer thin film capacitor of the present invention,
The area occupied by the capacitor on the substrate can be reduced and the density of surface mounting can be increased. Further, it is possible to reduce the manufacturing cost. Therefore, the present invention can be widely used in the field of electronic components.

[Brief description of drawings]

FIG. 1 shows an example of an electrical connection diagram of a multilayer thin film capacitor according to the present invention.

FIG. 2 shows an example of a plane cross section taken along the line AA of the internal electrode having the connection shown in FIG.

3 is a cross-sectional view showing an example of a multilayer thin film capacitor having the connection of FIG.

FIG. 4 is a plan view of a fired body in the form of a laminated substrate during the manufacturing process of the laminated thin film capacitor according to the present invention.

[Explanation of symbols]

 1 Internal Electrode 1a Openings 2a, 2b Conductor 3 Dielectric 4 RC Substrate 5 Overcoat 6 Conductor Pad (External Electrode) 7 Multilayer Thin Film Capacitor Unit 8 Cut Line

Claims (1)

[Claims] 1. A multilayer thin-film capacitor having a plurality of parallel internal electrodes sandwiching a dielectric and external electrodes connected to the internal electrodes, for performing necessary electrical connection between the internal electrodes. A via hole through which a conductor passes is provided in the dielectric body, and an opening larger than the diameter of the via hole is provided in the internal electrode where connection to at least one of the conductors is not desired, and a connection through the opening is desired. A laminated thin-film capacitor, characterized in that an insulating portion made of the above-mentioned dielectric is provided between a non-conductor and the internal electrode, and the opposing internal electrodes are internal electrodes having different polarities.