JPH0440849B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a laminated ceramic chip component, and particularly to a laminated ceramic chip component used for high-density packaging such as a hybrid IC board. [Background Art] In recent years, the development of hybrid ICs and the increase in the density of component mounting have been accelerated with the aim of downsizing and total cost reduction of electronic devices and equipment.
Along with this, high-density wiring of electronic circuit boards and chipping of mounted components have become essential elements. On the other hand, with the development of high-density wiring on hybrid IC boards, conventionally after mounting components, the surface of the board, including the mounted components, is overcoated with epoxy resin, silicone resin, etc. This is intended to prevent migration of silver-based materials used in component terminal electrodes, etc. Furthermore, with the advent of hybrid ICs, capacitors, inductors, varistors, etc., are increasingly being mounted as small, thin, and surface-mountable chip-type components, especially laminated ceramic chip components. As shown in FIG. 4, the structure of these laminated ceramic chip parts includes a ceramic sintered body 1, internal electrodes 2, and external electrodes 5. The main component of these materials is palladium for the internal electrodes 2, and a silver-palladium metal containing glass frit for the external electrodes 15. By laminating, high performance is imparted to a compact shape, and the number of laminated layers, that is, the number of internal electrodes 2 in the ceramic sintered body 1, will continue to increase from about 10 to about 20 to 50. . [Problems to be Solved by the Invention] The above-described conventional laminated ceramic chip components are mounted on a hybrid IC board or a high-density electronic circuit board, then overcoated with a coating resin and incorporated into various electronic devices and devices. In particular, when the overcoat resin was a heat-curable silicone material, deterioration of laminated ceramic chip parts was experienced. This is because the hydrogen gas generated during the curing reaction from heat-curing silicone is absorbed by palladium metal, which is a component of the external electrode 5, which is a component of conventional laminated ceramic chip parts, and is passed through this to the main part of the internal electrode 2. The component palladium or platinum metal is occluded and its volume expands, leading to destruction of the ceramic sintered body 1, that is, cracking of the laminated ceramic chip component. A drawback is that the so-called hydrogen absorption phenomenon of palladium or platinum metals leads to a decrease in the reliability of laminated ceramic parts. The object of the present invention is to provide a ceramic sintered body containing palladium and platinum as main components, which can suppress reliability deterioration due to hydrogen absorption phenomenon under hydrogen gas storage or overcoated with heat-curing silicone resin. An object of the present invention is to provide a laminated ceramic chip component having internal electrodes made of conductive metal. [Means for Solving the Problems] The laminated ceramic chip component of the present invention consists of a ceramic sintered body and a plurality of pieces formed inside the ceramic sintered body, the main component of which is palladium, one end of which is alternately exposed to the outside. A laminated ceramic chip component comprising an internal electrode and an external electrode layer electrically connecting exposed ends of the internal electrode, wherein the external electrode layer is at least one conductive metal coating layer that does not contain palladium or platinum. It consists of:
According to the present invention, it is possible to prevent hydrogen gas from being absorbed and attracted to the internal electrode layers of a laminated ceramic chip component in a usage environment where hydrogen gas is generated. Furthermore, the present invention can be applied to ceramic capacitors, ceramic inductors, and ceramic varistors, and also includes a connecting interface layer that connects the ceramic sintered body surface and the internal electrode end as an external electrode layer, and a palladium layer formed on the connecting interface layer. This can be effectively implemented by including at least one conductive metal coating layer that does not contain platinum. [Example] Next, the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a first embodiment of the invention. In a laminated ceramic chip having a plurality of internal electrodes 2 formed inside a ceramic sintered body 1 and having one end exposed to the outside alternately, a silver paste containing glass frit is applied and baked on the top of the connecting interface layer 3. A conductive metal coating layer 4 is formed. The conductive metal film layer 4 is formed by sputtering or plating of a metal that does not contain palladium or platinum and exhibits hydrogen gas absorbability. In this example, 5 to 10 μm of nickel plating was applied. Second
3 are schematic sectional views of second and third embodiments of the present invention. In FIG. 2, the external electrodes of the first embodiment,
That is, by adding an external electrode layer 5 on top of the connection interface layer 3 and the conductive metal coating layer 4, connection characteristics etc. can be improved. Further, FIG. 3 shows an example in which a metal not containing palladium or platinum is directly deposited by sputtering or vapor deposition to form the conductive metal coating layer 4 as the first layer. Next, a multilayer ceramic chip component according to the present invention was manufactured using a multilayer ceramic capacitor, and the following tests were conducted. The test sample is 3.2 mm long, 1.6 mm wide, and thick
The first electrode had an external shape of 1.0 mm, palladium was used as the internal electrode material, a silver layer containing glass frit was used as the connection interface layer as the external electrode of the example of the present invention, and then a nickel layer was formed as a conductive metal coating layer by electroplating. A chip component having the structure shown in the figure and a conventional chip component having the structure shown in FIG. 4 in which the external electrode was 85% silver and 15% palladium including glass frit were used. The test conditions are (1) After mounting the test sample on a ceramic board by soldering and coating with heat-curing silicone resin, the capacitance is measured after being left at a temperature of 85°C for 500 hours, and the capacitance is measured relative to the initial capacitance. Items with a change rate of 30% or more are considered defective. Next, (2) the test sample was left in hydrogen gas at 1 atm and room temperature for 48 hours, and then the appearance of the sample was observed with a 10x magnifying glass to confirm the number of defects such as cracks and breaks. The test results are shown in Table 1.

〔Effect of the invention〕

As explained above, the present invention provides at least one layer that does not contain palladium or platinum as an external electrode layer that electrically connects the exposed ends of internal electrodes that are mainly composed of palladium or platinum and is formed inside a ceramic sintered body. By having a conductive metal coating layer, it is possible to suppress reliability deterioration due to the hydrogen absorption phenomenon of laminated ceramic chip parts under (1) exposure to hydrogen gas or (2) usage environments where they are overcoated with heat-curing silicone resin. effective.

[Brief explanation of drawings]

1 to 3 are schematic cross-sectional views of embodiments of the laminated ceramic chip component of the present invention, and FIG. 4 is a schematic cross-sectional view of a conventional laminated ceramic chip component. 1... Ceramic sintered body, 2... Internal electrode, 3
... Connection interface layer, 4 ... Conductive metal coating layer, 5 ...
...External electrode layer, 15...External electrode.

Claims (1)

[Scope of Claims] 1. A ceramic sintered body, and an interior made of a conductive metal mainly composed of palladium or platinum, which is formed in a plurality of sheets inside the ceramic sintered body, and one end of which is alternately exposed to the outside. A laminated ceramic chip component comprising an electrode and an external electrode layer electrically connected to an exposed end of the internal electrode, wherein the external electrode layer includes at least one conductive metal layer that does not contain palladium or platinum. A laminated ceramic chip component featuring: 2. Claim 1, characterized in that the laminated ceramic chip component is a ceramic capacitor, a ceramic inductor, or a ceramic varistor.
Laminated ceramic chip parts described in Section 1. 3. The external electrode layer includes a connecting interface layer between the surface of the ceramic sintered body and the exposed surface of the internal electrode, and at least one layer containing no palladium or platinum formed on the connecting interface layer.
3. A laminated ceramic chip component according to claim 1 or claim 2, characterized in that it comprises two conductive metal coating layers.