JPS63211611A - Manufacture of capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a capacitor using a ceramic substrate as a dielectric, and in particular, a method for manufacturing a capacitor suitable for a capacitor having a high capacitance value per unit area of the substrate. Regarding.

[Conventional technology]

Conventionally, capacitors using a ceramic substrate as a dielectric material have been described, for example, in "Thick Film IC Technology, pp. 83-85, 53 Capacitors" edited by the Japan Microelectronics Association and published by Kogyo Chosenkai, published on December 1, 1983. Pattern design J wedge-shaped planar capacitor, i.e. No. 8
As shown in the plan view in FIG. 9 and in the cross-sectional perspective view in FIG. The conductor 4 is formed of a plurality of protruding portions 4c alternately spaced apart, and the portions 4a.

A capacitor is introduced in which a longitudinal section 4' between 4b and 4b is used as a counter electrode.

[Problem that the invention seeks to solve]

In the above conventional technology, the area of the opposing electrode, which is one of the coefficients that determines the capacitance value, is extremely small, and the capacitance value per unit area of the substrate is also low, making it impractical.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art as described above, and to provide a method for manufacturing a capacitor that has a high capacitance value of υ per unit area of a substrate and can adjust the capacitance through a simple process. .

[Failure to solve the problem]

The above purpose uses an electrically insulating silicon carbide ceramic substrate as a dielectric, and heats a part of this substrate with a laser beam.
The silicon carbide is melted and the electrical insulation property of the silicon carbide is destroyed to form a good conductor used as a counter electrode of a capacitor inside the substrate, and this good conductor has a capacitance value per unit area of the substrate of a predetermined value. This is achieved by forming the structure to hold the .

[Effect]

For electrically insulating silicon carbide ceramic substrates, 100
When heated at a high temperature of 0° C. or higher, silicon carbide has the property of breaking down its insulation properties and becoming a good conductor. The present invention utilizes this property to heat and melt a part of the substrate with a laser beam, thereby making it possible to form a conductor inside the substrate.This good conductor is formed in parallel and used as a counter electrode. In particular, the area of the opposing electrode becomes larger, and the capacitance value per unit area of the substrate can be increased.

Furthermore, when forming the above-mentioned good conductor, by measuring its capacitance and stopping the formation of the above-mentioned good conductor when it reaches a predetermined value, it is possible to form the counter electrode and adjust the capacitance value at the same time. It can be simplified.

〔Example〕

1 to 3 showing embodiments of the present invention will be described below.

As shown in FIG.
conductors 4a, 4b are formed.

Next, while measuring the capacitance between the two conductors 4a and 4b, the SiC substrate 1 is irradiated with a laser beam from one conductor 4a to the other conductor 4b, and the SiC
The substrate 1 is sequentially heated and melted to form a good conductor portion 3. At this time, the laser beam stops at a position where the good conductor portion 3 is a certain distance a from the other conductor 4b on the one conductor 4a side.

Next, the SiC substrate 1 is irradiated with a laser beam from the other conductor 4b toward the one conductor 4a to form a good conductor portion 3. At this time, the formed good conductor 3 must not overlap with the good conductor part 3 formed from one conductor 4a to the other conductor 4b, and the laser beam should not be directed to the good conductor part 3. 3 must be stopped at a certain distance a' from one conductor 4a and at a position on the other conductor 4b side.

Next, a good conductor portion 3 is formed from the one conductor 4a to the other conductor 4b, and this is repeated until a predetermined capacitance value is reached between these two conductors 4a and 4b. When the laser beam irradiation is then stopped, the capacitor is formed into the shape shown in FIG.

Further, the irradiation of the laser beam is stopped when the laser beam is initially irradiated from one conductor 4a to the other conductor 4b, even when the good conductor portion 3 is being formed. This is also done when a predetermined capacitance value is reached between these two conductors 4a and 4b.

The capacitor thus formed has a large opposing electrode area, as shown in cross section in FIGS. 2 and 3, and can have a high capacitance value per unit area of the substrate 1.

In this embodiment, a thin laser beam machining trajectory 2 remains on the upper surface of the good conductor portion 3. This occurs when the power of the laser beam is relatively weak.

Further, in this embodiment, two conductors 4a and 4b are used for the mutual connection of the good conductor portion 3, but the present invention is not limited to this. For example, the good conductor portion 3 may be
It is also possible to connect

Further, in this embodiment, the good conductor portion 3 is formed only in a straight line, but is not limited to this, and may be formed in an L shape or a curved shape.

Next, FIG. 4 showing another embodiment of the present invention will be described.

In FIG. 4, the power of the laser beam is made stronger than the cases shown in FIGS. 1 to 3, and as the power of the laser beam is increased, the insulation of silicon carbide of the substrate The amount of damage caused by the electrolyte is increased, and the area of the opposing electrode is increased.9, as shown in FIG. The electrode area is the widest, and the thickness of the substrate 1 can be used most effectively.

Next, FIG. 6 showing still another embodiment of the present invention will be described.

FIG. 6 shows a case where the good conductor portions 5 shown in FIG. 4 are formed on both sides of the substrate 1 at different positions.

FIG. 7, which shows another embodiment of the present invention, is a combination of the one shown in FIG. 6 and the one shown in FIG. By combining in this way, even higher capacitance or composite capacitors can be created.

〔Effect of the invention〕

According to the present invention, the following effects are achieved. That is, (1) As a capacitor using a ceramic substrate as a dielectric, the capacitance value per unit area of the substrate can be increased several times to several tens of times (depending on laser processing conditions and shape) compared to the conventional capacitor.

(2) It can be done in a simple process by just laser processing the substrate.

(3) Since processing is performed using a laser beam, there is a high degree of freedom in shape.

(4) Since electrode formation and capacitance value adjustment can be performed at the same time, workability is good.

(5) Composite capacitors can also be formed by the electrode construction method.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a capacitor showing one embodiment of the present invention;
2 is a sectional perspective view of FIG. 1, FIG. 3 is a partially enlarged sectional perspective view of FIG. 2, and FIGS. 4 to 7 are enlarged sectional perspective views of capacitors showing other embodiments of the present invention. , FIG. 8 is a plan view of a conventional capacitor, and FIG. 9 is a cross-sectional perspective view of FIG. 8. 1...Substrate 2...Laser processing trace 3...Good conductor part Figure 1 System 22
3 good 4 body aS4α, +b guide nu'r mouth 1 rod handling IAs mouth C

Claims (1)

[Claims] 1. Using an electrically insulating silicon carbide ceramic substrate as a dielectric, a portion of this substrate is heated and melted with a laser beam to destroy the electrical insulation properties of the silicon carbide and make the substrate a good conductor that can be used as a counter electrode of a capacitor. A method for manufacturing a capacitor, characterized in that the capacitor is formed so that a capacitance value per unit area of the substrate is maintained at a predetermined value.