JPH0677280U - Ceramic multilayer board - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a ceramic multilayer substrate having a structure in which a short circuit of a capacitor does not occur during manufacturing. In a ceramic multi-layer substrate having a structure in which a capacitor formed by sandwiching a high dielectric constant material 6 between electrodes 4 and 5 is built in a ceramic body 2, at least the ceramic body 2 and the high dielectric constant material 6 are provided. Insulating layers 11-1 and 11 are provided at the portions where the interface 12 with the electrodes 4 and 5 are in contact with each other.
-2 is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a ceramic multilayer substrate having a structure in which a capacitor formed by sandwiching a high dielectric constant material between electrodes is built in a ceramic body.

[0002]

[Prior art]

 Conventionally, a ceramic body made of a material such as alumina is provided with a multilayer wiring layer, and upper and lower wiring layers are used as electrodes, and a high dielectric constant material is sandwiched between these electrodes to form a capacitor. Various ceramic multilayer substrates are known.

FIG. 3 is a diagram showing a configuration of a capacitor portion in an example of a conventional ceramic multilayer substrate with a built-in capacitor. In the example shown in FIG. 3, 21 is an upper ceramic body, 22 is an intermediate ceramic body, 23 is a lower ceramic body, 24 is an upper electrode provided in the upper ceramic body, and 25 is provided in the lower ceramic body. The lower electrode, 26 is a high dielectric constant material provided between the upper electrode 24 and the lower electrode 25 in the middle layer ceramic body 22.

[0004]

[Problems to be solved by the device]

 In order to obtain a ceramic multilayer substrate with a built-in capacitor having the above-mentioned structure, it is usually necessary to prepare a middle-layer green tape in which a high-dielectric-constant tape is embedded in the green tape, and the lower electrode is screen-printed on the surface of the lower-layer green tape On top, form the upper electrode by screen printing on the middle layer of green tape, finally place the upper layer of green tape, and then place the required number of layers of wiring layers and green sheets, and finally burn in this state to manufacture. is doing.

However, when the ceramic substrate with a built-in capacitor is obtained as described above, since the high dielectric constant tape has a structure embedded in the green tape, a gap exists at the interface between the high dielectric constant tape and the green tape. However, there is a problem that the metal such as Ag forming the electrode diffuses during firing, causing a short circuit between the upper electrode and the lower electrode, and thus not functioning as a capacitor.

An object of the present invention is to solve the above problems and to provide a ceramic multilayer substrate having a structure in which a short circuit of a capacitor does not occur during manufacturing.

[0007]

[Means for Solving the Problems]

 The ceramic multi-layered substrate of the present invention is a ceramic multi-layered substrate having a structure in which a capacitor formed by sandwiching a high-dielectric constant material between electrodes is built in the ceramic body. An insulating layer is provided at a portion where the interface with the body and the electrode are in contact with each other.

[0008]

[Action]

 In the above-described structure, the insulating layer provided at least between the interface between the ceramic body and the high dielectric constant body and the electrode prevents diffusion of the electrode material through the interface between the ceramic body and the high dielectric constant body during firing. It is possible to prevent the short circuit between the electrodes.

[0009]

【Example】

 FIG. 1 is a diagram showing a configuration of a capacitor portion in an example of the ceramic multilayer substrate of the present invention. In the example shown in FIG. 1, 1 is an upper layer ceramic body, 2 is an intermediate layer ceramic body, 3 is a lower layer ceramic body, 4 is an upper electrode provided in the upper layer ceramic body 1, and 5 is provided in a lower layer ceramic body. The lower electrode 6 is a high dielectric constant material made of barium titanate, etc., which is provided between the upper electrode 4 and the lower electrode 5 in the middle layer ceramic body 2. Similar to the example. In this example, the ceramic body is described as the upper layer, the middle layer, and the lower layer for convenience of description, but in an actual ceramic multi-layer substrate, these layers cannot be separated as one unit.

What is important in the ceramic multilayer substrate of this embodiment is that the upper insulation made of a material such as glass is provided between the upper electrode 4 and the high dielectric constant body 6 and between the lower electrode 5 and the high dielectric constant body 6. The point is that the layer 11-1 and the lower insulating layer 11-2 are provided to insulate at least the interface 12 between the middle-layer ceramic body 2 and the high dielectric constant body 6 and the upper electrode 4 and the lower electrode 5. Therefore, the upper insulating layer 11-1 and the lower insulating layer 11-2 should prevent the diffusion of the metal such as Ag of the upper electrode 4 and the lower electrode 5 toward the interface 12 even during firing of the ceramic multilayer substrate. You can

Even if the upper insulating layer 11-1 and the lower insulating layer 11-2 are provided to insulate the high dielectric constant body 6 from the upper electrode 4 or the lower electrode 5 as in this embodiment, Only the capacitor composed of the insulating layers 11-1 and 11-2 is connected in series to the capacitor composed of the high-dielectric constant material 6, and the capacity of the capacitor as a whole is slightly reduced. It goes without saying that it works.

In order to obtain the ceramic multilayer substrate having the above-described structure, a middle layer green tape in which a high dielectric constant tape is embedded in a green tape is prepared, a lower electrode is screen-printed on the surface, and a lower insulating layer is further formed. It is placed on the screen-printed lower layer green tape, the upper insulating layer and the upper electrode are formed on it by screen printing on the middle layer green tape, and finally the upper layer green tape is placed, and wiring for the required number of layers. It can be manufactured by placing the layers and the green sheet and finally firing in this state. To embed the high-dielectric-constant tape in the green tape, a conventionally known method such as a method of punching holes in the green tape and embedding the high-dielectric-constant tape in the holes with a punch can be used.

FIG. 2 is a diagram showing a capacitor portion in another example of the ceramic multilayer substrate of the present invention. In the example shown in FIG. 2, as in the example shown in FIG. 1, the upper insulating layer 11-1 and the lower insulating layer 11-2 are formed on the entire surface between the upper electrode 4 and the lower electrode 5 and the high dielectric constant material 6. The upper insulating layers 11-1 and 11-2 are provided only at the positions corresponding to the interface 12 between the middle-layer ceramic body 2 and the high dielectric constant body 6, unlike the case where the upper insulating layers 11-1 and 11-2 are arranged. In the ceramic multilayer substrate having the structure shown in FIG. 2, as in the case shown in FIG. 1, the upper electrode 4 and the lower electrode 5 are intercalated through the metal interface 12 such as Ag during firing for manufacturing the ceramic multilayer substrate. Can be prevented from spreading.

[0014]

[Effect of device]

 As is clear from the above description, according to the present invention, since the insulating layer is provided at least between the interface between the ceramic body and the high dielectric constant body and the electrode, it is possible to perform firing during the production of the ceramic multilayer substrate. At times, it is possible to prevent the diffusion of the electrode material through the interface between the ceramic body and the high dielectric constant material, and to prevent a short circuit between the electrodes.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a capacitor portion in an example of a ceramic multilayer substrate of the present invention.

FIG. 2 is a diagram showing a configuration of a capacitor portion in another example of the ceramic multilayer substrate of the present invention.

FIG. 3 is a diagram showing a configuration of a capacitor portion in an example of a conventional ceramic multilayer substrate.

[Explanation of symbols]

 1 Upper Layer Ceramic Body 2 Middle Layer Ceramic Body 3 Lower Layer Ceramic Body 4 Upper Electrode 5 Lower Electrode 6 High Dielectric Constant 11-1 Upper Insulating Layer 11-2 Lower Insulating Layer 12 Interface

Claims (1)

[Scope of utility model registration request] 1. A ceramic multilayer substrate having a structure in which a capacitor formed by sandwiching a high dielectric constant material between electrodes is built in the ceramic body, and at least an interface between the ceramic body and the high dielectric constant material and the interface. A ceramic multi-layer substrate, characterized in that an insulating layer is provided at a portion in contact with the electrode.