Analysis on the main points of the fabrication of chip multilayer ceramic capacitors

This article will introduce the structure and manufacturing process of multilayer ceramic capacitors.

Basic structure of multilayer ceramic capacitor

The capacitor is used to store charge, and its most basic structure is shown in Fig. 1. A dielectric body is sandwiched between the two electrode plates.

The performance of a capacitor also depends on how much charge can be stored. In order to be able to store more power, the multilayer ceramic capacitor is realized by multiple stacking of the structure in FIG. Figure 2 is the basic configuration.

After the dielectric material is prepared, it is mixed with various solvents and the like and pulverized to form a mud solder. After making a thin patch, the patch multilayer ceramic capacitor can be produced through the eight steps described below.

1 internal electrode printing of dielectric board

A metal solder is applied to the rolled dielectric plate as an internal electrode.

In recent years, multilayer ceramic capacitors have been dominated by Ni internal electrodes. Therefore, the dielectric plate is coated with Ni solder.

2 laminated dielectric board

After the internal electrode solder is applied to the dielectric plate, it is laminated.

3 stamping process

Pressure is applied to the laminate, and the pressure is integrated. In the previous process, in order to prevent the intrusion of foreign matter, it is basically dust-free.

4 cutting process

The laminated dielectric block is cut into a predetermined size such as 1.0 mm × 0.5 mm or 1.6 mm × 0.8 mm.

5 baking process

The cut piece is fired at a temperature of about 1000 to 1300 degrees. By firing, the ceramic and internal electrodes will be integrated.

6 coated external electrode, fired

Metal solder is applied to both ends of the fired sheet material to serve as an external electrode. In the case of a Ni internal electrode, a Cu solder is applied and then sintered at a temperature of about 800 degrees.

7 plating process

After the external electrode is fired, a layer of Ni and Sn is also plated on the surface. Electrolytic plating is generally used, Ni is plated for reliability, and Sn is plated for easy mounting. The chip capacitor is basically completed in this process.

8 measurement and packaging process (supplement)

Confirm that the final completed chip capacitor has the proper electrical characteristics and can be shipped after the roll is packaged. In recent years, with the miniaturization and increase in capacity of multilayer ceramic capacitors, various processes have been improved, for example, the dielectric layer is highly thinned, and the lamination accuracy is improved.