JPH04337617A - Manufacture of multilayer electronic part - Google Patents

Abstract

PURPOSE:To maintain the maximum performance for extended periods of time by surely connecting an internal electrode to an outside electrode so as to prevent the degradation of the characteristics of multilayer electronic parts. CONSTITUTION:Provided is a plurality of ceramic green sheet 5 containing a ceramic green sheet 5, on whose surface, an inside electrode 3 is formed and whose inside electrode 3 is pulled out to the end planes 5a, 5b. It is manufacturing method of a multilayer electronic part that these sheets are laminated and backed integrally, and outside electrodes 4A, 4B to be connected to the inside electrode 3 are formed on the inside electrode pull-out end planes 2a, 2b of the backed body 2. Before forming the outside electrodes 4A, 4B, a process is added where the inside electrode pull-out end planes 2a, 2b are ground to the surface roughness of 5mum.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of Industrial Application The present invention relates to a method of manufacturing a multilayer electronic component, which is formed by sintering a plurality of stacked ceramic green sheets and forming external electrodes connected to internal electrodes on the end faces of the sintered body.

0002

2. Description of the Related Art Conventionally, there has been a multilayer piezoelectric element shown in FIG. This laminated piezoelectric element 1 includes a ceramic sintered body 2. The ceramic sintered body 2 has internal electrodes 3, 3, . . . therein. This internal electrode 3 is led out to one of the end faces 2a and 2b of the sintered body 2. Also,
External electrodes 4A, 4B are formed on opposing end surfaces 2a, 2b of the sintered body 2, and are connected to the internal electrodes 3 by contacting them.

As shown in FIG. 2, the ceramic sintered body 2 is formed by laminating a plurality of ceramic green sheets 5 and sintering them together. Internal electrodes 3 made of electrode paste and extending up to one of the sheet end surfaces 5a and 5b are applied to some surfaces of the ceramic green sheet 5.

[0004] Such a laminated piezoelectric element 1 utilizes the ceramic sintered body 2, so it has the advantage that it can be made thinner and that a large amount of vibration displacement per constant electric field strength can be obtained accordingly. There is.

[0005]

[Problems to be Solved by the Invention] However, in such a laminated piezoelectric element 1, the inner electrode 3 and the outer electrode 4
There was a problem in that not only the connection with A and 4B was not reliable, but also the characteristics could not be maintained for a long period of time.

[0006] The ceramic sintered body 2 is simply a stack of ceramic green sheets 5 and sintered, and the end surfaces thereof are rough and uneven. Furthermore, although the internal electrodes 3 are formed to extend up to the ceramic green sheet end surfaces 5a and 5b, they are completely formed over the entire surface of the sheet end surface 5a.
, 5b cannot be said to be exposed. On the contrary,
The external electrodes 4A and 4B are generally formed on the sintered body 2 by vapor deposition or plating.
formed on the end face of However, if the external electrodes 4A, 4B are formed with the end surfaces as described above, not only will it not be possible to obtain sufficient adhesive strength, but also it will not be possible to securely connect the internal electrode 3 and the external electrodes 4A, 4B over the entire surface of the end surfaces 2a, 2b. It was impossible to do so. Therefore, when performance tests such as heat cycle tests and continuous drive tests were performed, the characteristics deteriorated significantly.

The present invention has been made in view of the above-mentioned problems, and provides reliable connection between internal electrodes and external electrodes.
The object of the present invention is to provide a method for manufacturing a laminated piezoelectric component that maintains its performance over a long period of time without causing characteristic deterioration.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a plurality of ceramic green sheets including ceramic green sheets each having an internal electrode formed on the surface thereof and having the internal electrode led out to the end surface of the sheet. Prepare,
A method for manufacturing a laminated electronic component, in which these are laminated and fired together, and an external electrode connected to the internal electrode is formed on the internal electrode lead-out end face of the fired body, wherein before forming the external electrode, The internal electrode lead-out end face has a surface roughness of 5.
It includes a process of polishing down to μm.

[0009]

[Operation] According to the above structure, when the internal electrode lead-out end face is sufficiently polished to a surface roughness of 5 μm, the unevenness of the end face disappears and the adhesive strength of the external electrode increases. Further, when the internal electrode lead-out end face is sufficiently polished, the internal electrodes are reliably exposed to the entire end face.

0010

EXAMPLES The present invention will be explained in detail below based on examples. This example is implemented in a laminated piezoelectric element like the conventional example, and the structure of the completed product is the same as that of the conventional example, and the same or similar parts are given the same reference numerals. That is, 1 is a laminated piezoelectric element, 2 is a ceramic sintered body, 3 is an internal electrode, and 4A and 4B are external electrodes formed on opposite end surfaces 2a and 2b of the ceramic sintered body 2 and connected to the internal electrode 3. The electrode 5 is a ceramic green sheet that constitutes the ceramic sintered body 2.

Next, the manufacturing method of the present invention will be explained.

First, a ceramic green sheet 5 is formed. That is, PbO, TiO2, ZrO2, NiO, Nb2O5, which are the raw materials of the ceramic green sheet 5
Prepare. Then, these are Pb(Ni1/3Nb2
/3) Weigh so that the composition becomes 0.4Zr0.2Ti0.4O3, and wet-mix these to form a mixture. This mixture was dehydrated and dried at 800-900°C.
to obtain a calcined product. Further, an organic binder is added to the calcined product and mixed, and then formed into a sheet to a predetermined thickness (for example, 40 μm) by a doctor blade method.

Further, after this ceramic green sheet 5 is cut into a predetermined size (for example, 9 mm x 8 mm), internal electrodes 3 are applied as shown in FIG. The internal electrodes 3 are connected to opposing end surfaces 5a, 5 of the ceramic green sheets 5.
It is led out to one side of b and is exposed on the end face.

Furthermore, these ceramic green sheets 5 are laminated. At this time, adjacent ceramic green sheets 5 are stacked with their internal electrode leading end faces 5a and 5b alternately different. Then, the laminate thus laminated is fired at a predetermined temperature (for example, 1200° C.) to obtain a fired body 2.

The next feature of this embodiment is that the internal electrode leading end surfaces 2a and 2b of this fired body 2 are made of #80
Polish the surface to a surface roughness of 5 μm using No. 00 polishing powder. Finally, gold, which will become the external electrodes 4A and 4B, is vapor-deposited on the internal electrode lead-out end faces 2a and 2b, and the multilayer piezoelectric element 1 is completed.

The inventor of the present invention tested the multilayer piezoelectric element 1 manufactured in this manner and a comparative example by a heat cycle test and a continuous drive test, and obtained the following experimental results. The Example products and Comparative Example products referred to herein refer to multilayer piezoelectric elements manufactured by the same or similar manufacturing method as above, which are polarized by applying a DC current of 3 to 4 kV/mm at 20 to 60° C. This refers to something that lasted 5 hours.

Furthermore, the example product has a surface roughness of 5 μm,
The comparative examples refer to those polished to a surface roughness of 7 μm and 10 μm, respectively. Also, heat cycle test is -40℃~125℃
This is a test in which a heat cycle of 120 degrees Celsius is repeated, and the continuous drive test is a test in which a voltage of 20 V is continuously applied for 1000 hours. In addition, the amount of displacement shown in the table (
μm) refers to the amount of displacement in the thickness direction when a DC voltage of 60V is applied.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Table 3]

As is clear from the above experimental results, the product of this example did not cause any connection failure between the internal electrode 3 and the external electrodes 4A, 4B even when subjected to such tests.
Therefore, the characteristics do not deteriorate. On the other hand, in the comparative example product, a connection failure occurred between the internal electrode 3 and the external electrodes 4A, 4B, and an inactive layer was formed due to this, resulting in a significant deterioration of the characteristics.

Furthermore, when the initial characteristics of each sample before the experiment are compared, it can be seen that the characteristics of the Example product and the Comparative Example product are clearly different, and the Example product has superior characteristics. This is because the connection between the internal electrode 3 and the external electrodes 4A, 4B is made securely in the example product, and as a result, the example product maximizes the inherent characteristics of the multilayer piezoelectric element 1. Seem.

[0023] Furthermore, when comparing the examples, it can be seen that they have similar performance regardless of whether the surface roughness is 5 μm or 3 μm. That is, no deterioration in characteristics is observed whether the surface roughness is 3 μm or 5 μm. This result shows that it is sufficient to polish the internal electrode lead-out end faces 2a and 2b to a surface roughness of 5 μm.

[0024]

As described above, according to the present invention, by adding a step of polishing the lead-out end face of the internal electrode to a surface roughness of 5 μm, it is possible to not only increase the adhesive strength of the external electrode but also completely remove the internal electrode. The internal electrode can now be exposed on the lead-out end face.

[0025] Therefore, it becomes possible to reliably connect the internal and external electrodes, and not only can the inherent characteristics of the multilayer electronic component be maximized, but also its performance can be maintained for a long time. It is now possible to cross and maintain it.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view of a laminated piezoelectric element, which is a laminated electronic component according to the present invention and a conventional example.

FIG. 2 is a perspective view showing a stacked state of ceramic green sheets.

FIG. 3 is a partially cutaway plan view of the laminated piezoelectric element.

[Explanation of symbols]

1 Laminated piezoelectric element 2 Sintered body 2a, 2b Internal electrode lead-out end surface 3 Internal electrode 4A, 4B External electrode 5 Ceramic green sheet 5a, 5b Sheet end surface

Claims (1)

[Claims] 1. A plurality of ceramic green sheets (5) including a ceramic green sheet (5) having an internal electrode (3) formed on the surface thereof and having the internal electrode (3) led out to the sheet end surface (5a, 5b). are prepared, laminated and fired together, and external electrodes (4A, 4B) connected to the internal electrodes (3) are formed on the internal electrode lead-out end faces (2a, 2b) of this fired body (2). A method for manufacturing a laminated electronic component, characterized by comprising the step of polishing the internal electrode lead-out end faces (2a, 2b) to a surface roughness of 5 μm before forming the external electrodes (4A, 4B). A manufacturing method for laminated electronic components.