JPS6052008A - Method of producing ceramic dielectric material for 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 the Invention The present invention relates to a method for producing a porous material whose main component is alumina (Tos) or forsterite (2Mg0-8iO□).

Structure and Problems of Conventional Examples Since microchip capacitors are manufactured for use in microcircuit elements, they are typically chip capacitors with a thickness of 200 μm or less and a negative side size of 500 μm or less. There are two manufacturing methods: one is to cut the dielectric ceramic into chips by machining such as cutting and polishing, and the other is to wet-form the dielectric to adjust the thickness to create a green sheet, and then bake the sheet and then cut it into chips. be.

In the conventional manufacturing method of microchip capacitors by firing under atmospheric pressure, chipping and cracking occur during machining, and machining distortion causes a significant decrease in Q. Furthermore, the presence of the bore reduces the dielectric constant and withstand voltage characteristics.

Purpose of the Invention The present invention eliminates the conventional drawbacks and provides a method for manufacturing a ceramic dielectric for capacitors that has a high density of 99% TD or more of theoretical density, high withstand voltage characteristics, low dielectric loss, and excellent mechanical properties. It is in.

Structure of the Invention The present invention provides a method for manufacturing a ceramic dielectric for a capacitor, characterized in that alumina ceramic or forsterite ceramic fired at atmospheric pressure is hot isostatically pressed to have a theoretical density of 99% TD or more. The method for transferring the data will be explained with an example.

The sample preparation process was carried out using commercially available industrial Kawahara layer (purity 99%).
(7) he2o3, Mg0, 2Mg0 ・
5i02, BaOO3, and BaZrO3 powders were blended to the composition ratio shown in Table 1, and when impurities were mixed in,
Wet mix using a Notan-lined pot and dry.

Table 1 (% by weight) A 1 M203M g 0 99.8 0.2 A 2 2Mg0・SiO,, BaO03BaZrO3
9613 The dried product was mixed with an aqueous polyvinyl alcohol solution as a binder and sized into 32 mesh passes. This sized powder is made into a square shape of 50 x 50 x 30 mm by 1t/7
These molded bodies were molded at 1550°C in the air for A1 in Table 1, and at 13°C in the air for A2.
It was fired at a temperature of 50°C.

The fired body was subjected to H-pressing (hot isostatic pressing) under the conditions shown in Table 2.

Table 2 H work P temperature H work P pressure Atmosphere A 1 1450°C 1.500 atm ArA 2
1300°C 11000at Ar The dielectric porcelain body thus obtained was cut to a thickness of 0.2 + by an internal blade cutting machine.
Slice into 0.5×0.mm slices using a peripheral blade.
Cut into 5Nn squares to obtain chips.

Au is deposited on the chip to form a microchip capacitor. Using the chip capacitor, the relative dielectric constant εr
(Measurement frequency i MH2), Q (I MH2), and boost breakdown voltage ratio vb (V/mm ) were measured. In addition, for ceramics, we measured the chip failure rate during cutting, bore distribution, and theoretical density ratio. The results are shown in Table 3. The comparison sample is H
It is not treated with P.

Table 3 The products of the present invention have excellent properties, such as an increase in εr of about 20%, QK of about 150 to 200%, and vb of about 20% compared to conventional products. When the theoretical density ratio is less than 99% TD, εr decreases and chips and chipping occur during machining, making it unsuitable for microchip capacitors.

Effect of the invention The present invention provides the following effects.

(1) A high-density ceramic with a theoretical density ratio of 99% TD or more can be obtained.

(2) Capacitor characteristics are improved and stabilized.

(3) Improved mechanical properties and yield during processing.

As described above, the method for manufacturing a microchip capacitor of the present invention has extremely excellent performance, is extremely stable even in industrial mass production, and produces effects that can be used industrially.

Patent applicant: Matsushita Electric Industrial Co., Ltd. °Representative Patent Attorney Isao Abe

Claims (1)

[Claims] Alumina ceramic or forsterite ceramic fired at atmospheric pressure is hot isostatically pressed, and the theoretical density is 9.
A method for manufacturing a ceramic dielectric for a capacitor, characterized in that the ceramic dielectric has a TD of 9% or more.