JPS6055977B2 - Manufacturing method of semiconductor grain boundary insulated multilayer ceramic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor grain-boundary insulated multilayer ceramic capacitor that is small in size, has a large capacity, and is easy to manufacture.

With the recent miniaturization of electrical equipment, there is a strong demand for miniaturization of electronic components.

Multilayer ceramic capacitors have been widely used so far because they are small and can provide large capacitance. However, if a larger capacity is required, there is a limit to miniaturization. It is generally known that semiconductor ceramic capacitors have extremely large capacitance values compared to other capacitors.

However, this type of capacitor has so far only been used as a so-called single-plate capacitor. The present invention has been made in view of the above points, and relates to a method for manufacturing a multilayer capacitor using grain boundary insulated semiconductor porcelain.

First, in the present invention, as shown in FIG. 1, ceramics such as barium titanate and strontium titanate, which are generally used for grain boundary insulated capacitors, are used for manufacturing conventional multilayer capacitors. Similarly, it is formed into a sheet 1.

First, a layer of metal oxide 5 for forming a grain boundary insulator such as copper, manganese, hismuth, etc. is applied on one plane of the porcelain sheet 1,
On the surface of this metal oxide 5, a layer of capacitive electrode 2 made of a high melting point metal such as gold, platinum, palladium, etc. is applied in a superimposed manner.

This capacitive electrode 2 is provided approximately at the center of the ceramic sheet 1 at a predetermined distance from the outer peripheral edge thereof. In this case, the shape of the metal oxide 5 is particularly arbitrary, but it is convenient for manufacturing to overlap it in the same shape as the capacitor electrode 5. On one plane of the ceramic sheet 1, a layer of an extraction electrode 3 for leading out the capacitor electrode 2 to one side end of the ceramic sheet 1 is provided continuously with a part of the capacitor electrode 2. Ru. It is preferable that the extraction electrode 3 is formed of the same material at the same time as the capacitor electrode 2 is provided. Note that the metal oxide 5 and the capacitor electrode 2 do not necessarily have to have the metal oxide 5 as the lower layer, and the same result can be obtained even if they are reversed. Next, a plurality of porcelain sheets 1 constructed in this manner are prepared, stacked so that the extraction electrodes 3 are alternately positioned, and pressed together to form a laminate 4. The specific means for forming this laminate 4 may be any conventionally known method. Next, this laminate 4 was
The laminate 4 is made into porcelain by firing in a neutral or reducing atmosphere at 50°C. At the same time, the metal oxide 5 is diffused into the grain boundaries of the laminate to form an insulating layer (not shown), and the capacitor electrode 2 is baked.

Finally, on each side end surface (and the vicinity thereof) from which the extraction electrode 3 is led out of the laminate 4 configured in this way,
An external connection electrode 6 is applied to each capacitor, and conductive connection is made to each capacitance electrode 2 to obtain a semiconductor grain boundary insulated multilayer ceramic capacitor.

As a means for applying the external connection electrode 6, plating, baking, adhesion, etc. may be used as in the conventional case. The multilayer ceramic capacitor obtained by the manufacturing method of the present invention is constructed in this manner, and has a large capacity in which the dielectric is an insulating layer formed at the grain boundaries of the ceramic.

Therefore, the size can be reduced as much as possible, and the set can be made smaller. Further, in the present invention, there is no need to change the manufacturing process much from that of the conventional method, and the electrical characteristics such as dielectric loss, insulation resistance, and temperature change resistance are almost the same as those of the conventional method. In the above example, an insulating layer was formed at the grain boundaries by diffusing the metal oxide 5 during firing of the laminate 4, but in order to make the formation of an insulating layer at the grain boundaries more stable, Similar results can be obtained even if the firing of the laminate 4 is performed in a separate process.

That is, a laminate 4 formed by stacking and pressing a plurality of porcelain sheets 1 is first fired in a neutral or reducing atmosphere at a temperature of 1,350 to 1,450°C to form the laminate 4 into porcelain. In this case, the metal oxide 5 is diffused into the grain boundaries of the stack 4. After that, the fired laminate 4 was heated to 100
Heat treatment is performed in a neutral or oxidizing atmosphere at a temperature of 0 to 1250° C. to form the metal oxide 5 diffused into the grain boundaries into a stable insulating layer. The remaining steps and means in this example may be the same as in the previous example, so their explanation will be omitted. Furthermore, the electrical properties of the multilayer ceramic capacitor obtained in this example were almost comparable to those of conventional capacitors. It should be noted that things that can be easily recognized from the explanation of each of the above examples of the present invention are naturally included in the scope of the present invention, and the present invention is not limited to the above-mentioned examples. I would like to add this.

[Brief explanation of the drawing]

FIG. 1 is a diagram specifically showing the present invention. DESCRIPTION OF SYMBOLS 1...Porcelain sheet, 2...Capacitor electrode, 3...Extractor electrode, 4...Laminated body, 5
...Metal oxide, 6...External connection electrode.

Claims (1)

[Scope of Claims] 1. A capacitor electrode layer made of a high-melting point metal on one plane of the porcelain sheet, and a capacitor electrode layer that is continuous with the capacitor electrode layer and led out to one side end of the porcelain sheet. A metal oxide layer for forming a grain boundary insulator is formed, which is overlapped with the capacitance electrode layer, and a plurality of these porcelain sheets are stacked and crimped so that the lead electrode layers alternate. forming a laminate, firing this laminate in a neutral or oxidizing atmosphere, and by this firing simultaneously converting the laminate into porcelain and forming an insulating layer at the grain boundaries of the laminate, A method for manufacturing a semiconductor grain boundary insulated multilayer ceramic capacitor, characterized in that an external connection electrode is then provided on each lead-out end face of the lead-out electrode layer. 2. The capacitor electrode layer made of a high-melting point metal and the metal oxide layer for forming a grain boundary insulator are applied in a superimposed manner on one plane of the ceramic sheet so that the metal oxide layer is the lower layer. A method for manufacturing a semiconductor grain boundary insulated multilayer ceramic capacitor according to claim 1. 3. A capacitive electrode layer made of a high melting point metal on one plane of the porcelain sheet, and an extraction electrode layer that is continuous with the capacitive electrode layer and leads out the capacitive electrode layer to one side end of the porcelain sheet. A metal oxide layer for forming a grain boundary insulator is formed so as to overlap with the capacitor electrode layer, and a plurality of these ceramic sheets are stacked and pressure-bonded so that the extraction electrode layers are alternately formed to form a laminate. After firing this laminate in a neutral or reducing atmosphere, it is heat-treated in a neutral or oxidizing atmosphere to stably form an insulating layer at the grain boundaries, and then on each lead-out end face of the lead-out electrode layer. A method for manufacturing a semiconductor grain boundary insulated multilayer ceramic capacitor, characterized in that it is provided with an electrode for external connection. 4. The capacitive electrode layer made of a high-melting point metal and the metal oxide layer for forming a grain boundary insulator are applied so as to be superimposed on one plane of the porcelain sheet, with the metal oxide layer being the lower layer. A method for manufacturing a semiconductor grain boundary insulated multilayer ceramic capacitor according to claim 3.