JPS61279165A - Manufacture of capacitor for hybrid integrated circuit - Google Patents

Abstract

PURPOSE:To obtain a capacitor, in which only a capacitance value is increased, by forming the capacitor on an insulating supporting plate, on which a glass layer having irregularities is formed, thereby increasing the effective area of the capacitor larger than the apparent area. CONSTITUTION:On an insulating supporting plate 1, a glass layer 2, which has a smooth irregularities 7 at a specified interval, is formed. On the glass layer 2, a capacitor, which comprises a tantalum layer 3, a lower electrode 5, which is taken out of the tantalum layer 3, a dielectric layer 4, which is formed by the anodic formation of the tantalum layer 3, and an upper electrode 6, which is provided on the dielectric layer 4, is formed. Then, the capacitor for an integrated circuit, which has the larger capacitance value than the capacitance value determined by the apparent area, is readily formed.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides a film technology to provide a capacitor as an auxiliary circuit element for an active element such as an integrated circuit chip on an insulating support plate on which an active element such as an integrated circuit chip is mounted. The present invention relates to a method of manufacturing a capacitor for a hybrid integrated circuit.

[Conventional technology]

Conventionally, as a manufacturing method for the above-mentioned container for a hybrid integrated circuit, a glass layer is formed on an insulating support plate such as alumina ceramic for the purpose of obtaining smoothness, and then a metal film is formed by sputtering or the like. For example, a method has been implemented in which an anodized insulator such as tantalum is used as a dielectric material.

[Problem that the invention seeks to solve]

In the capacitor manufacturing method described above, in order to obtain a large capacitance value, it is necessary to reduce the thickness of the dielectric film or increase the area occupied by the capacitor.

FIGS. 2(a) to 2(d) are cross-sectional views showing a conventional manufacturing method. First, as shown in FIG. 2(a), a glass layer 12 is deposited on an insulating support plate 1 made of alumina ceramic or the like in order to obtain smoothness, and then, as shown in FIG. 2(b),
The glass R is formed by sputtering a metal, such as tantalum, which can be made into a dielectric material by anodizing or the like.
After forming a film on the tantalum layer 12 and the support plate l, the tantalum layer 3 is patterned into a predetermined shape by a method such as chemical etching. Next, as shown in FIG. 2(C), a part of the tantalum layer 3 is made into a dielectric material 4 by a method such as anodization, and then as shown in FIG. 2(d).
As shown in the figure, a lower lead electrode 5 and an upper electrode 6 are formed on the exposed uncured bottom portion of the tantalum 3 and the dielectric layer 4, respectively, to complete the capacitor.

In the above manufacturing method, the capacitance value is determined by the planar area of the capacitor and the thickness of the dielectric 4. If you want to obtain a larger capacitance value, the planar surface ff is determined. There are methods such as increasing the size of the capacitor and making the dielectric 4 thinner, but if the area is increased, the area occupied by the capacitor on the insulating support plate will not be large and the substrate will be large. Further, if the dielectric film thickness is made thinner, there is a drawback that the withstand voltage decreases, which is likely to cause defects.

[Means for solving problems]

In the method of the present invention, by fabricating a capacitor on an insulating support plate on which a glass layer with unevenness is formed, the effective area of the capacitor can be made larger than its apparent planar area. However, compared to capacitors made using conventional methods, it is possible to manufacture capacitors with increased capacitance without increasing the area occupied by the capacitor.

〔Example〕

Next, the present invention will be explained using examples. Figure 1(a)
-(d) are cross-sectional views for explaining a method according to an embodiment of the present invention. FIG. 1(a) shows a state in which a glass layer 2 having smooth irregularities 7 at regular intervals is formed on an insulating support plate 1 made of alumina ceramic or the like. Hereinafter, Fig. 1 CI)) to (d) show states corresponding to Fig. 2 (b) to (d), respectively. As shown in (d), support plate 1
A tantalum layer 3, a lower electrode 5 drawn out from the tantalum layer 3, a dielectric layer 4 formed by anodizing the tantalum 3, and a dielectric layer are placed on the glass layer 2, which has an uneven upper surface. An empty capacitor is formed with the upper electrode 6 provided on top of the capacitor 4.

〔Effect of the invention〕

As described above, by implementing the present invention, it is possible to easily produce a capacitor for an integrated circuit having a larger capacitance value than the capacitance value determined by the apparent area.

[Brief explanation of drawings]

FIGS. 1(a) to 1(d) are cross-sectional views of one embodiment of the present invention in the order of manufacturing steps, and FIGS. 2(a) to (d) are cross-sectional views of the conventional method in the order of manufacturing steps. DESCRIPTION OF SYMBOLS 1... Insulating support plate, 2, 12... Glass layer, 3.
...Mental layer, 4...Dielectric layer, 5...Lower extraction electrode, 6...Upper electrode, 7...Irregularities. A certain figure

Claims (1)

[Claims] A capacitor for a hybrid integrated circuit, characterized in that a smooth unevenness is formed on the surface of a glass layer on an insulating support plate, and a dielectric layer is formed on the surface of the glass layer along the uneven surface. Production method.