JP2000232027A - Manufacture for laminated electronic components - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a method for manufacturing laminated electronic components in which relative density as a laminated body is made uniform. SOLUTION: Materials equivalent to green sheet materials are used as supplementary agent for parts other than electrode components on a green sheet 50, so that the thickness of the green sheet 50 can be made uniform, regardless of the presence or absence of any electrode component by this basic means. Also, even when the thickness of the electrode parts is different from that of the other parts on the individual green sheet 50, generation of faults at the boundary part of the electrodes of each green sheet can be prevented synergistically with the close-by green sheet layer by forming supplementary layers 51. Thus, a more inexpensive and more reliable laminate can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a small electronic component.

[0002]

2. Description of the Related Art Many electronic parts such as small electronic parts, such as chip inductors, chip capacitors and actuators, and alumina multilayer substrates, are made of a magnetic material, a dielectric material, a piezoelectric material or an alumina (Al2O3) material on a green sheet. After producing conductive materials by printing technology or vapor deposition method, coating method, etc., they were stacked and sent to the process after molding, and each processing such as cutting and sintering was performed. In order to obtain a desired capacity while responding to the demand for miniaturization, electrodes must be provided on a thinner green sheet and stacked in multiple layers, and the thickness of the part with and without the electrode is reduced by the thickness of the electrode. A difference corresponding to the thickness occurs, and when the laminate is laminated under pressure and subjected to a firing step, a difference in internal pressure causes cracks, and there is a serious problem in the performance of electronic components. (For example, supervised by Shigeyuki Somiya,
Kanji Otsuka, Ceramic Multilayer Power Distribution Board, published by Uchida Rokaku, Chapter 5, pp. 93-116. )

[0003]

According to the present invention, when a small and large-capacity electronic component is produced, it is necessary to reduce the thickness of the laminate and increase the number thereof. in this case,
Although it is possible to make the thickness of the electrode sufficiently thin, from the viewpoint of the function as an electrode, it is necessary to keep the electrode surface resistance low, so that when the printing method is used, 2 μm or less should be avoided.
However, since the thickness of the green sheet has recently been produced up to about 10 μm, even if the electrode thickness is reduced, a ratio of a difference in thickness between a portion where the electrode is applied and a portion where the electrode is not applied occurs. When molding into a laminate, a step occurs inside the laminate,
In the worst case, the effective thickness of the electrode layer is reduced, and when the piezoelectric material is a green sheet material,
At the time of polarization, the current density in that portion becomes high, causing cracks due to extreme abnormal heat generation, which is a serious drawback. In addition, if the material of the green sheet constitutes an inductor with a magnetic material, in the above-described case, the electrode functions as a coil. Increases with a decrease in the effective area of the electrode, resulting in a large loss (tan δ), which is also a serious drawback as a target electronic component. Next, when the green sheet is made of a dielectric material, the multilayer capacitor in the above-described state has a reduced withstand voltage, and at the same time, has an unstable capacitance, and cannot satisfy the requirements as an electronic component requiring reliability. Can not. In other words, a laminated electronic component in which no measures are taken while the electrodes are provided on the green sheet, for example, a piezoelectric actuator, a piezoelectric transformer, a laminated inductor composed of a magnetic substance, a laminated capacitor composed of a dielectric, etc. When the number is increased, there is a problem that it causes a serious defect, and it is difficult to increase the number of layers.

[0004]

A typical example of a conventional laminated electronic component in which a piezoelectric material (PZT) is used as a material of a green sheet 11 and an electrode material is made of a noble metal Ag-Pd to form an actuator. FIG. 1A shows a cross-sectional view of the laminated structure. Each of the green sheets 11 has an electrode 15
When the sheet 12 having no electrode is covered on the uppermost portion, a gap is generated in the portion 14 where no electrode is provided. In this case, the relative density ρ is extremely low as compared with a portion having no electrode as shown in FIG. 2B. When this laminated product is put in a sealed bag and subjected to hydrostatic pressure, as shown in an enlarged view of a boundary portion 21 between a portion with and without an electrode as shown in a sectional view in FIG. It is not uncommon to deform and break. As a means for solving the above-mentioned problem, there is provided the present invention characterized in that a void portion generated due to no electrode application is filled with a material having the same or substantially similar performance as a green sheet.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS There are many types of laminated electronic components, but all of them relate to a manufacturing method. The fundamental idea is that parts other than the parts on which electrodes are provided are originally designed. It is characterized by supplementing a material that does not impair the performance of the device. When the green sheet is a piezoelectric material, the filler is a piezoelectric material, a magnetic material for an inductor, a dielectric material for a capacitor, and a magnetic material or a laminated filter. By supplementing the dielectric material alone or with a mixture, it is possible to manufacture a reliable electronic component according to the original purpose of the electronic component.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A feature of the present invention relates to a method of manufacturing a laminated electronic component. A green sheet which does not impair the performance of the electronic component is provided on a portion of the green sheet constituting the laminate where no electrode is provided. It is an object of the present invention to obtain a highly reliable electronic component by using the same material or a similar material as a filler, making uniform the relative density of the green sheets in a stacked state. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. An example of a piezoelectric actuator composed of a piezoelectric material as a laminated electronic component will be described in detail with reference to a model drawing, but basically, a gap generated in a portion of the green sheet without electrodes, which is a feature of the present invention, Averaging the relative density of the laminate with the same or similar filler as the green sheet that does not impair its purpose is the same for other electronic components. On the green sheet, a peripheral portion 31 as shown in FIG. 3A is closed, and an electrode 32 is used for printing an electrode with a mask provided with an opening 32 inside (Ag-Pd).
The paste is printed, and then the same material as the green sheet material is finely pulverized by using a mask shown in FIG. 5% by weight of molecular polyvinyl butyral with respect to 100 finely pulverized, trichlorethylene 20
%, Tetrachlorethylene 10%, and butyl alcohol 15%, respectively, and kneaded in a ball mill for 5 hours to form a paste, which is used as a material for filling gaps. 3
5, in other words, the portion 35 other than the electrode portion 36 has a form in which the printing surface uniformly spreads over the entire surface as shown in FIG. As shown in FIG. 4, the cross section in the direction perpendicular to the paper surface connecting the points C and C in FIG. 3C is such that an electrode layer 42 is provided by printing on a piezoelectric green sheet 43, and a piezoelectric material 41 was supplemented. Compensation part 4
1 is T = Δt + t,
The condition of Δt ≦ 0 is satisfied. Ideally, the above-mentioned means is used to perform the replenishment operation for each green sheet, but it is not necessary to provide the green sheet on all the green sheets due to the physical conditions of the green sheet, for example, the thickness, the molding method, the number of laminations, etc. However, it is needless to mention that the present invention is not limited to the case where the number of layers in a practically allowable range is compensated for, and it follows from the idea of making the relative density of the laminate uniform.
As shown in an example in A, when the number of electrode layers is six and the filling portion 51 is two on the right side and one on the right side, the thickness of the filling portion that can compensate for the difference between the respective electrode pressures is required. On the right side, Δt = t / 2 because the gap without the electrode in the center portion only needs to be filled with the filling portions on both sides. On the right side, Δt =
2t is ideal. The magnitude of Δt can be determined depending on the type of electronic component. For example, for those requiring extremely uniformity, Δt = 0 since a supplementary layer is provided for each green sheet.
On the other hand, when a supplementary layer is provided for a large number of layers, Δt increases. Since the increase in the number of operations in terms of cost increases the cost, the number of necessary replenishments must be determined for each target electronic component. The electronic component manufactured in this way has a uniform performance in which the partial relative density of the laminate is uniform as shown in FIG. 5B and has stable performance.

[0007]

According to the present invention, there is provided an electronic component according to the present invention, characterized in that in the manufacturing process of the laminated electronic component, voids other than the electrode portion of the green sheet are filled with the same or similar material as the green sheet. In the manufacturing method, since the partial relative density of the laminate is made uniform, the multilayer electronic component has an effect of exhibiting stable performance, and is industrially valuable.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view showing a state in which green sheets 11 on which electrodes 15 are printed are stacked in a process of manufacturing a conventional multilayer electronic component. Numeral 12 is the uppermost covering sheet, and numeral 14 is a void formed at a place other than the electrode portion on the green sheet. FIG.
The vertical axis represents the relative density ρ of the laminate and the horizontal axis represents the position.

FIG. 2 is a cross-sectional view showing a state in which a step is formed at a boundary portion 21 on which no electrode is printed when the laminate is placed in a sealed bag and subjected to pressurization by hydrostatic pressure; Some are enlarged.

FIG. 3 is a front view of a printing mask used in the present invention. FIG. 3A shows an opening 32 for printing an electrode and a closed portion 31 around the opening 32. FIG. FIG. 2B shows a mask for printing a material equivalent to the green sheet material, in which the electrode printed portion 34 is closed and the outer portion 33 of the electrode portion is opened. FIG. C shows a positional relationship in which FIGS. A and B are overlapped with each other, in which the inside is an electrode printed portion 36 and the outside is a portion 35 printed with the same material as the green sheet.

FIG. 4 is a cross-sectional view showing a state in which a portion other than the electrode printed portion 42 of the green sheet 43 according to the present invention is filled with a filler such as a material equivalent to that of the green sheet by printing, and Indicates the thickness of the electrode layer, and T indicates the thickness of the supplementary layer.

FIG. 5A is a cross-sectional view showing an example of a laminate according to the present invention. Numeral 50 indicates that the layers other than the electrodes are sufficient in other layers without supplementing a filler. Compensation layer 5
In the case of having a thickness of 1, the gap portion is complemented, and the state where the relative density is achieved, which is the target, is shown in FIG.

Claims (1)

[Claims] 1. A supplement layer made of an insulating material which is the same as the material of the green sheet or which does not impair the purpose as an electronic component, is provided on a portion other than the electrode portion made of a conductive material on the green sheet. A method for manufacturing a laminated electronic component, characterized in that the relative density as a laminate is made uniform.