CS260879B1 - Method of disk-shaped one-layer ceramic condensers production - Google Patents

Abstract

The essence of the solution is a mass production method ceramic plate capacitors of chemically plated ceramic dielectric. This effect is achieved grinding facets on peripheral parts of a full-area disk ceramic dielectric, thereby forming an insulating material a gap separating the two electrodes. Sharpening facets of the selected width can be performed Capacitor Capacitance. \ t optional value.

Description

BACKGROUND OF THE INVENTION The present invention relates to a process for the production of single-layer disc-shaped ceramic capacitors in which insulating gaps are formed between the electrodes by removing a metal coating with facetted dielectrics.

The basic function of the ceramic capacitor - capacity - is formed on the ceramic dielectric by electrodes, which are separated from each other by an insulating gap. At present, the most used technology of creating electrodes of single-layer ceramic capacitors is the deposition of silver suspensions and subsequent firing of metallic deposits. Insulation gaps arise on ceramic dielectrics either when the metal suspensions are applied to the electrode surfaces by screen printing, brushing, masking or the like, or full-area metallized ceramic plates are cut with diamond tools and the insulating gap is then the dielectric thickness. The plated plate cutting technology is applicable to the manufacture of ceramic capacitors even in the electrode forming process by electroless plating, eg copper or nickel plating. Today, rectangular foil single-layer capacitors are produced using this technology. Replacement of deficient silver with base metals in the disc constructions of ceramic capacitors by electroless plating has the potential to create an insulating gap. Application of suspensions. of metals for the subsequent firing is practically unusable, since it requires a reducing or inert atmosphere in which most dielectrics undergo changes that result in a semiconducting state. Creating insulating gaps by grinding on centerless grinders is a laborious and complex operation. Also, the formation of base metal electrodes in such structures by magnetron sputtering requires, in addition to complex and energy-intensive equipment, an extensive system of masks and stencils with the need for complex cleaning.

These drawbacks are overcome by the process according to the invention, which consists in the use of electroless plating of the entire surface of the disk ceramic dielectric in the manufacture of disk ceramic capacitors and the formation of insulating gaps between the electrodes by mass grinding on facets on ceramic circular plates. The new method of creating insulating gaps allows grinding of suitable facets at the same time on a large set of wafers.

Ceramic dielectrics. The circular shape, metallized over the entire surface, is machined in a cylindrical vessel of a selected inner diameter into which they are inserted together with the liquid grinding suspension. After closing, the cylindrical vessel is placed in a horizontal position in a speed-adjustable rotary motion about its. longitudinal axis. By free-sliding movement on the inner wall of the rotating cylindrical vessel coupled with the rotation and reversal of the metallized ceramic dielectrics, facets are ground at the edges of the circumference of the ceramic dielectrics corresponding to the curvature of the inner wall of the cylindrical vessel of the selected inner diameter. By using a cylindrical vessel with a suitable diameter, the facets create a perfect insulating gap at the edges of the circumference and the cylindrical portion of the ceramic disc separating the two electrodes thus formed.

By possibly further abrading the transition of the chamfer to the planar portion of the metallized disk ceramic dielectric in a cylindrical vessel with a larger inner diameter, a very narrow tolerance of the nominal value of the capacitance of the capacitors produced can be achieved. In this way, insulating gaps and electrodes of selectable size can be formed on the metallized disk dielectrics.

The advantages of the invention reside in the possibility of introducing mass production of disc ceramic capacitors with base metal electrodes electrolessly deposited on ceramic dielectrics, where it is not possible to use cutting technology of full-metalized dielectric. The higher effect of the process of manufacturing the ceramic disk capacitors of the invention, compared to the prior art, is in the possibility of creating insulating gaps of selectable size between the two electrodes.

The process for producing the disc ceramic capacitors according to the invention is illustrated by the following example.

A nickel layer 2 of the required thickness is electrolessly deposited onto the ceramic dielectric of the disc shape 1. Removal of the nickel coating at the insulating gap is accomplished by forming facets at the periphery and cylindrical portion of the ceramic dielectric. Further processing of the metallized dielectrics thus obtained is carried out in a conventional manner.

Claims (2)

SUBJECT 1. A process for the manufacture of disk-shaped single-layer ceramic capacitors, characterized in that a full-surface metallized ceramic dielectric is placed in a cylindrical vessel of selected inner diameter, which is provided with a liquid suspension with free abrasive. facets for peripheral INVENT the parts of the full-area ceramic dielectric with an insulating gap separating the two electrodes. 2. A process for producing single-layer disc ceramic capacitors according to claim 1, characterized in that by grinding a facet of selected width in a cylindrical vessel of gradually larger diameter, the capacitor capacitance is adjusted to an optional value on the metallized disc dielectric.