JP3877382B2 - Manufacturing method of multilayer capacitor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, one internal electrode and the other internal electrode are alternately laminated with a dielectric sheet interposed therebetween to form a chip body, and a terminal for the one internal electrode is formed on one end surface of the chip piece. The present invention relates to a method of manufacturing a multilayer capacitor in which electrodes are formed on the other end surface of a chip body and terminal electrodes for the other internal electrodes are formed.
[0002]
[Prior art]
Conventionally, in the production of this type of multilayer capacitor, for example, methods described in JP-A-61-144811 and JP-A-1-312817 and the methods shown in FIGS. Has been.
That is, first, as shown in FIG. 17, on the surface of the first ceramic green sheet B1 constituting the dielectric sheet, a large number of one internal electrode A1 is formed by screen printing, while the same dielectric sheet is formed. A large number of the other internal electrodes A1 are formed on the surface of the second ceramic green sheet B2 to be formed by screen printing. A plurality of the first ceramic green sheets B1, a plurality of the second ceramic green sheets B2, Are stacked alternately, and a ceramic green sheet B3 for cover is stacked on the upper and lower surfaces, and then pressed in the stacking direction to form a stacked body C as shown in FIG.
[0003]
Next, the stacked body C is cut into a plurality of chip bodies A3 along the vertical cutting lines D1 and the horizontal cutting lines D2, as shown in FIGS. After A3 is baked at a high temperature in a baking furnace, terminal electrodes A4 and A5 are formed on the left and right end faces A3 ′ and A3 ″, respectively.
[0004]
[Problems to be solved by the invention]
However, this conventional manufacturing method has the advantage that many pieces can be manufactured simultaneously from one laminate, but there are problems as described below.
That is, in the conventional manufacturing method, as described above, the dielectric sheet is manufactured in the form of the ceramic green sheets B1 and B2, and the internal electrodes A1 and A2 are formed thereon by screen printing and then overlapped. Therefore, the ceramic green sheets B1 and B2 have a sufficient thickness so that the ceramic green sheets B1 and B2 are not torn during handling such as a process of forming internal electrodes by screen printing. Accordingly, the thickness dimension obtained by superposing a plurality of ceramic green sheets B1 and B2 is greatly increased.
[0005]
In other words, in the conventional manufacturing method, the dielectric sheet is manufactured in the form of ceramic green sheets B1 and B2, and the internal electrodes A1 and A2 are formed on the dielectric sheets. The thickness of the sheets B1 and B2 must be considerably increased, and the height H of the chip body A3 formed by superposing a plurality of these ceramic green sheets is remarkably increased, so that the capacitance of the capacitor is determined. In such a case, there is a problem that not only the capacitor is increased in size but also the weight is increased, and if the size of the capacitor is determined, the capacity is reduced.
[0006]
An object of the present invention is to provide a method of manufacturing a multilayer capacitor that solves this problem.
[0007]
[Means for Solving the Problems]
In order to achieve this technical problem, the production method of the present invention comprises:
“ First step of forming a dielectric sheet for the internal electrode by applying and drying the material for the dielectric sheet on the surface of the ceramic green sheet after forming the internal electrodes in a large number of capacitors,
Next, the surface of the dielectric sheet according to the first step is made flat by pressing in the thickness direction using a flat plate and applying / drying the dielectric sheet material to the recessed portion of the surface. 2 processes,
Next, after forming the internal electrodes of the capacitors on the surface of the planar dielectric sheet, a dielectric sheet for the internal electrodes is formed by applying and drying a dielectric sheet material. 3 steps,
Next, the surface of the dielectric sheet according to the third step is made flat by pressing in the thickness direction using a flat plate and applying and drying the dielectric sheet material on the recessed portion of the upper surface. 4 steps,
Next, after repeating the third step and the fourth step a plurality of times, a fifth step of further stacking ceramic green sheets to form a laminate,
Next, the step of forming the terminal electrode on each chip body after cutting the laminated body into chip bodies for each capacitor and firing,
It has . " .
[0008]
[Operation and effect of the invention]
Thus, in the present invention, the dielectric sheet between the internal electrodes is formed by applying and drying the material, and the internal electrodes are formed on the dielectric sheet. Thus, after each dielectric sheet is manufactured in the form of a ceramic green sheet, it can be made so thin that it cannot be compared with the case where the internal electrode is formed on the dielectric sheet.
[0009]
Therefore, according to the present invention, the thickness of the multilayer body is significantly reduced, and as a result, the height of each chip body obtained by cutting the multilayer body can be significantly reduced, so the capacitance of the capacitor is determined. In this case, the capacitor can be reduced in size and weight, and if the size of the capacitor is determined, its capacity can be increased.
[0010]
By the way, as described above, after forming a large number of one internal electrode on the surface of the ceramic green sheet, a dielectric sheet material is applied and dried to form a dielectric sheet, and then this dielectric sheet In the case where a dielectric sheet is formed by applying and drying a material for a dielectric sheet after forming a plurality of other internal electrodes on the surface, the surface of each dielectric sheet includes Since the internal electrode part protrudes and the part other than the internal electrode is depressed, the height dimension of each chip body is caused by the central part where each internal electrode overlaps. It tends to become a drum-like shape, such as being high and low in the surrounding area.
[0011]
On the other hand, the present invention, as described above, after forming each dielectric sheet by coating and drying the material , presses the plate in the thickness direction with a flat plate, and dielectrics the concave portion of the surface. It was decided to make the surface of each dielectric sheet formed by applying and drying the material substantially flat so as to eliminate irregularities. Therefore, it is possible to reliably avoid the tendency of each chip body to become a drum shape, and to make each chip body a rectangular shape having a substantially complete shape.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
First, as shown in FIG. 1, a ceramic green sheet 1 for the cover is prepared, and one internal electrode 2 in each of a large number of capacitors is screened on the surface of the ceramic green sheet 1 as shown in FIG. Formed by printing.
[0013]
Next, as shown in FIGS. 3 and 4, a slurry liquid obtained by mixing a dielectric material powder and a solvent or a dielectric material powder is applied to the surface of the ceramic green sheet 1. The first dielectric sheet 3 is formed by applying a thin film so as to cover and drying.
The above application is performed by spraying the slurry liquid or dielectric substance powder by spraying, or applying the slurry liquid with a brush or a roller.
[0014]
In this case, the surface of the first dielectric sheet 3 formed as described above can be uneven so that the portions of the internal electrodes 2 of the surface protrude and the portions other than the internal electrodes 2 are depressed. Become.
Therefore, after the first dielectric sheet 2 is formed, as shown in FIG. 5, in addition to being sandwiched between a pair of upper and lower plane plates E1 and E2 and pressed in the thickness direction , FIG. As shown, by applying a slurry liquid 3a in which a dielectric substance powder and a solvent are mixed to a hollow portion of the surface of the first dielectric sheet 3 or a dielectric substance powder and then drying, The surface of the first dielectric sheet 3 is planar.
[0015]
Next, as shown in FIG. 7, the other internal electrode 4 of each capacitor is formed on the surface of the first dielectric sheet 2 by screen printing, and as shown in FIGS. A slurry liquid in which a substance powder and a solvent are mixed, or a dielectric substance powder is applied in the form of a thin film so as to cover each internal electrode 4 in the same manner as in FIGS. Then, the second dielectric sheet 5 is formed by drying.
[0016]
Next, as shown in FIG. 10, in addition to being sandwiched between a pair of upper and lower plane plates E1 and E2 and pressed in the thickness direction , as shown in FIG. 11, of the surface of the second dielectric sheet 5 the portion of the recess, the slurry liquid 5a by mixing a powder and a solvent of the dielectric material, or by drying after the application of the powder of the dielectric material, the surface of the second dielectric sheet 5 in a plane .
[0017]
Then, on the surface of the second dielectric sheet 5, as shown in FIG. 12, a plurality of one internal electrode 2 is formed by screen printing, and then the first dielectric is formed by the same method as described above. Forming the body sheet 3 and forming a plurality of other internal electrodes 4 on the surface of the first dielectric sheet 2 by screen printing are repeated a predetermined number of times. Further, as shown in FIG. 13, after the ceramic green sheets 6 for covering are overlapped, the whole is pressed in the thickness direction, thereby forming the laminate 7 as shown in FIG.
[0018]
Next, the laminated body 7 is cut into chip bodies 8 for each of a large number of capacitors , as shown in FIGS. 15 and 16, along the vertical cutting line D1 and the horizontal cutting line D2. After the step of firing each chip body 8 at a high temperature in a firing furnace, a terminal electrode 9 electrically connected to each internal electrode 2 is provided on one end face 8a of the left and right end faces 8a, 8b. The terminal electrode 10 that is electrically connected to the one internal electrode 4 is formed on the other end face 8b, thereby completing the multilayer capacitor.
[0019]
Thus, in the present invention, the dielectric sheets 3 and 5 are not manufactured in the form of a ceramic green sheet and the internal electrodes are formed on the dielectric sheets 3 and 5 as in the prior art. Since the internal electrodes are formed on the dielectric sheets 3 and 5 after being formed, the thickness of each of the dielectric sheets 3 and 5 can be reduced so as not to be compared with the conventional one. Thus, the height dimension H of each chip body 8 obtained by cutting the laminated body 7 can be greatly reduced.
[0020]
In addition, after the dielectric sheets 3 and 5 are formed, they are flattened by pressing in the thickness direction with a flat plate and applying and drying the dielectric sheet material on the concave portions of the surface. By adding a process to the above, the height dimension H of each chip body 7 is high in the central portion where the internal electrodes 2 and 4 are overlapped, and becomes a drum-like shape so as to be low in the peripheral portion. By eliminating the tendency, each chip body 7 can be formed into a substantially perfect rectangular shape.
[Brief description of the drawings]
FIG. 1 is a perspective view of a ceramic green sheet used in an embodiment of the present invention.
FIG. 2 is a perspective view showing a state in which one internal electrode is formed on the surface of the ceramic green sheet.
FIG. 3 is a perspective view showing a state in which a first dielectric sheet is formed on the surface of the ceramic green sheet.
4 is an enlarged sectional view taken along line IV-IV in FIG. 3;
FIG. 5 is an enlarged cross-sectional view showing a state in which the first dielectric sheet is formed and then pressed in the thickness direction.
FIG. 6 is an enlarged cross-sectional view showing a state in which the unevenness of the surface of the first dielectric sheet is leveled after the first dielectric sheet is formed.
FIG. 7 is a perspective view showing a state in which the other internal electrode is formed on the surface of the first dielectric sheet.
FIG. 8 is a perspective view showing a state in which a second dielectric sheet is formed on the surface of the first dielectric sheet.
9 is an enlarged sectional view taken along the line IX-IX in FIG.
FIG. 10 is an enlarged cross-sectional view showing a state where the second dielectric sheet is formed and pressed in the thickness direction.
FIG. 11 is an enlarged cross-sectional view showing a state in which unevenness on the surface of the second dielectric sheet is leveled after the second dielectric sheet is formed.
FIG. 12 is a perspective view showing a state in which one internal electrode is formed on the surface of the second dielectric sheet.
FIG. 13 is a perspective view showing a state in which ceramic green sheets for a cover are overlaid.
FIG. 14 is a perspective view of a laminated body.
FIG. 15 is a perspective view showing a chip body obtained by cutting the laminated body.
16 is a sectional view taken along line XVI-XVI in FIG.
FIG. 17 is a perspective view showing a conventional method.
FIG. 18 is a perspective view showing a laminate in a conventional method.
FIG. 19 is a perspective view showing a chip body according to a conventional method.
20 is a sectional view taken along line XX-XX in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ceramic green sheet for cover 2 One internal electrode 3 1st dielectric sheet 4 Other internal electrode 5 2nd dielectric sheet 6 Ceramic green sheet for cover 7 Laminated body 8 Chip body 8a, 8b End surface of chip body 9,10 Terminal electrode

Claims (1)

A first step of forming a dielectric sheet for the internal electrode by applying and drying a material for the dielectric sheet on the surface of the ceramic green sheet after forming the internal electrodes of a plurality of capacitors;
Next, the surface of the dielectric sheet according to the first step is made flat by pressing in the thickness direction using a flat plate and applying / drying the dielectric sheet material to the recessed portion of the surface. 2 processes,
Next, after forming the internal electrodes of the capacitors on the surface of the planar dielectric sheet, a dielectric sheet for the internal electrodes is formed by applying and drying a dielectric sheet material. 3 steps,
Next, the surface of the dielectric sheet according to the third step is made flat by pressing in the thickness direction using a flat plate and applying and drying the dielectric sheet material on the recessed portion of the upper surface. 4 steps,
Next, after repeating the third step and the fourth step a plurality of times, a fifth step of further stacking ceramic green sheets to form a laminate,
Next, the step of forming the terminal electrode on each chip body after cutting the laminated body into chip bodies for each capacitor and firing,
A method for producing a multilayer capacitor, comprising:

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