JPH0752698B2 - Method for manufacturing monolithic ceramic capacitor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a monolithic ceramic capacitor having a small variation in electrostatic capacitance.

[Prior Art] Conventionally, a monolithic ceramic capacitor is manufactured as follows.

First, a slurry-like mixed solution in which a raw material powder to be a dielectric material and an organic binder are mixed, and a long base film such as polyethylene terephthalate are prepared. The mixed solution is evenly applied on the long base film by a coating method such as a doctor blade method to a thickness of a few tens of μm to a few tens of μm, and the mixture is allowed to pass through a drying oven to vaporize the organic solvent. At the same time, the mixed solution is dried to form a long ceramic green sheet on the base film. Further, after peeling this long ceramic green sheet from the base film, it is cut into a predetermined size, and the cut sheet is attached to a metal frame-shaped frame to form a printing sheet.

Next, a printing machine for printing internal electrodes on the ceramic green sheet formed as described above and a screen frame used for printing are prepared. In this case, the screen frame is made of stainless steel, nylon, etc. (called a stencil) with dimensions that fit the screen printing machine.
The photo-curable resin is applied to this stencil, and a pattern in which a plurality of internal electrodes are arranged vertically and horizontally is formed by the photoetching method.The resin in the pattern part is removed, and the other part is covered with the resin. A printing screen is formed.

The printing screen thus formed is set in the printing machine, and the printing sheet attached to the frame is set below the printing screen. Then, the conductive paste is applied onto the stencil, and the squeegee is moved while being pressed against the stencil, and from the pattern formed on the printing screen, the applied conductive paste is extruded onto the green sheet for printing. Print on the sheet. The printed pattern of the multilayer ceramic capacitor printed as above is, for example, 4.0 mm ×
Two patterns, an A pattern of about 0.7 mm and a B pattern obtained by moving the A pattern by 2.5 mm in the longitudinal direction, are prepared, and printing is performed using a pattern group consisting of the respective patterns.

Further, as shown in FIG. 4 (a), two types of green sheets having internal electrodes printed by the above two pattern groups.
As a method of stacking 10 and 11, as shown in FIG. 4 (b),
A pattern green sheet 10 on the predetermined position of the frame
After alternately stacking and green sheets 11 of B pattern, punching and crimping, they are cut vertically and horizontally at the positions indicated by X-X and Y-Y in the figure, and shredded to a fine dimension of 2.5 mm × 1.6 mm. To be done. In addition, in order to facilitate understanding in the figure, a part of the four rows at the end of the green sheet is shown. Finally, after firing these, a conductive paste was applied to both ends and baked to form external electrodes, thus manufacturing a monolithic ceramic capacitor as shown in FIG.

This multilayer ceramic capacitor is
Dielectric ceramic layers 20a and 20b having internal electrodes 22a and 22b, which are alternately shifted to the left and right by a pattern and a B pattern shifted by a half pitch, are alternately laminated, and further, ceramics having no electrodes on both sides thereof. The layer 21 is crimped. Then, the internal electrodes 22 thus laminated
External electrodes 23a, 23b are arranged so that the internal electrodes 22a, 22b are in contact with both end faces of a, 22b and the ceramic layers 20a, 20b, 21, respectively.
Are formed.

However, in the above conventional method for manufacturing a monolithic ceramic capacitor, the pattern A and the pattern B are formed on the ceramic green sheet.
In order to print the two types of internal electrode patterns of the pattern, two different types of stencil had to be prepared.

Therefore, as a method of forming an internal electrode pattern with one type of stencil, for example, as shown in Japanese Patent Application Laid-Open No. 57-198617, pattern groups having the same arrangement in which the internal electrode patterns are shifted by half pitch every other row. Print and arrange on a green sheet, and every other 180 sheets of this green sheet
Known are a method of inverting and laminating, and a method of cutting the internal electrode pattern into odd-numbered columns and sequentially laminating them.

[Problems to be Solved by the Invention] However, as described in Japanese Patent Application Laid-Open No. 57-198617, a method of inverting and stacking every other green sheet by 180 degrees requires a high-level technique for inverting. In addition, the reversing operation causes a stacking deviation of the green sheets, and there is a drawback that the stacking accuracy is low.

In addition, in the method of cutting the internal electrode pattern every several rows and sequentially laminating it, it is not necessary to invert the green sheets by 180 degrees and stacking them, but the green sheets are laid out every tens or hundreds of odd rows. When cutting and stacking, the internal electrode patterns separated by tens or hundreds of columns on the stencil are vertically stacked. Therefore, due to the difference in the position on the stencil, more specifically, the printing deviation caused by the difference in the printing pressure of the squeegee in the central portion and the peripheral portion,
It is unavoidable that the upper and lower internal electrode patterns are misaligned, and the stacking accuracy is also limited.

In recent years, monolithic ceramic capacitors are becoming smaller and smaller, and in order to improve productivity, the green sheets are cut in large quantity units, such as every several hundred rows of internal electrode patterns. It becomes a problem.

Therefore, an object of the present invention is to provide a method for manufacturing a monolithic ceramic capacitor having higher lamination accuracy.

[Means for Solving the Problems] That is, in order to achieve the above object, in the present invention, first, a pattern in which a conductive paste is applied on a dielectric green sheet and a plurality of internal electrode patterns are printed vertically and horizontally In the method for manufacturing a laminated ceramic capacitor, in which groups are arranged, punched into a predetermined size for each pattern group, laminated, pressure-bonded, and then fired, the internal electrode patterns A and B are shifted by half a pitch every other row and are identical. Array pattern group,
The same stencil is used to print and array on the green sheet 12, the pattern groups are alternately staggered by an odd number of rows and punched out, and they are sequentially laminated. .

Second, a conductive paste is applied on the dielectric green sheet, and a plurality of internal electrode patterns are printed vertically and horizontally to form a pattern group, which is punched into a predetermined size for each pattern group, laminated, and pressure-bonded. In the method of manufacturing a laminated ceramic capacitor which is then fired, internal electrode patterns A and B are used.
Pattern group of the same array shifted by half a pitch every other row, both using the same stencil, printed on the green sheets 12, 13 by staggering alternately for odd columns of the same pattern group,
Provided is a method for manufacturing a monolithic ceramic capacitor, which comprises arranging, punching out the pattern groups without shifting in the column direction, and sequentially laminating them.

[Operation] According to the method for manufacturing a monolithic ceramic capacitor according to the present invention, different A patterns and B patterns can be printed using one stencil to form internal electrode patterns.

Moreover, in this case, the rows of the pattern may be shifted by any odd row of one or more rows. Therefore, if the number is reduced to one row or three rows, the difference in the position on the stencil, more specifically, However, the print misalignment caused by the difference in the printing pressure of the stage between the central portion and the peripheral portion causes almost no problem.

Therefore, when these are laminated and fired, variations in the pattern overlapping accuracy do not occur, and a multilayer ceramic capacitor with extremely small variations in capacitance can be manufactured.

[Examples] Examples of the present invention will be specifically described below.

First, the steps until the raw material powder to be the dielectric material is made into the ceramic green sheet for printing are the same as those in the conventional example, and therefore the description is omitted. As in the case of FIG. 4 of the conventional example, FIGS. 1 and 2 show only a part of the four rows at the end of the green sheet in order to facilitate understanding.

First, as shown in FIG. 1 (a), the A pattern in the first row is 4.
The shape of 0 mm x 0.7 mm is formed at intervals of 0.6 mm.
Next, as the B pattern in the second row, first, 1.8 m so that the extension line of the side end of the A pattern in the first row is located in the center.
Form an m × 0.7mm shape, then form a large number of 4.0mm × 0.7mm shapes with a spacing of 0.6mm, and finally form the above 1.8mm × 0.7mm shape. To do. That is,
The second row of the B pattern is a pattern group of the same arrangement, which is shifted by a half pitch from the first row of the A pattern through the shape of 1.8 mm × 0.7 mm formed on both end sides. Print and arrange on the green sheet 12.

After the groups of patterns having the same arrangement are printed and arranged, as shown in FIG. 1 (b), the groups of patterns are punched out by alternately shifting them by an odd number of columns, and then sequentially laminating them. After crimping, shred to 2.5 mm x 1.6 mm in length and width at the positions indicated by XX and YY in the figure, and after firing, apply conductive paste to both ends and bake,
External electrodes were formed to manufacture a monolithic ceramic capacitor.

Next, as a second manufacturing method, as shown in FIG. 1A, a pattern group having the same arrangement in which the internal electrodes A pattern and B pattern are shifted by half pitch every other row
As shown in FIG. 5A, another pattern group to be printed and arranged on the green sheet 13 is formed by alternately shifting the pattern groups by an odd number of columns. In this way, printing using the pattern group formed from the same pattern on the printing screen,
The arranged green sheets 12 and 13 were punched without shifting in the row direction as shown in FIG. 2 (b). Then, they are sequentially laminated, and these are pressure-bonded, and X-X and Y in the figure
A multilayer ceramic capacitor was manufactured by cutting it into pieces of 2.5 mm × 1.6 mm in length and width at the position indicated by -Y.

Randomly extract 100 monolithic ceramic capacitors manufactured by the above two methods, measure the capacitance, and show the spread of the measurement distribution as standard deviation / average value (σ /). The value is σ / =
It was 2.3%. As a comparative example of this numerical value, when a laminated ceramic capacitor manufactured by a conventional method was measured under the same conditions, it was σ / = 3.4%.

[Effects of the Invention] As is clear from the above description, according to the method for manufacturing a monolithic ceramic capacitor according to the present invention, it is possible to obtain a monolithic ceramic capacitor having high pattern lamination accuracy and therefore small variation in capacitance. Be able to manufacture.

[Brief description of drawings]

FIG. 1 (a) is a plan view showing a state in which a plurality of patterns are printed on the same green sheet according to the first embodiment of the present invention, and FIG. 1 (b) is a plurality of patterns formed as described above. FIG. 2 (a) is a plan view showing a state in which the layers are stacked.
FIG. 1 is a plan view showing a state in which a plurality of patterns are printed on the same green sheet according to the second embodiment of the present invention, and FIG. 1B shows a state in which a plurality of patterns formed as described above are laminated. A plan view and FIG. 3 (a) are cross-sectional views showing the structure of a monolithic ceramic capacitor, FIG. 3 (b).
FIG. 4A is a partially cutaway perspective view showing the structure of a monolithic ceramic capacitor, and FIG. 4A is a plan view showing a state in which each single pattern is printed on a separate green sheet by a conventional method. FIG. 4 (b) is a plan view showing a state in which a plurality of patterns formed as described above are laminated. A, B ... Print pattern, 10, 11, 12, 13 ... Ceramic green sheet, 20a, 20b ... Dielectric ceramic layer,
21 ... Ceramic layer, 22a, 22b ... Internal electrodes, 23a, 23b
...... External electrode

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Takahashi 6-16-20 Ueno, Taito-ku, Tokyo Within Taiyo Electric Co., Ltd. (56) References JP-A-57-198617 (JP, A) JP 63-49363 (JP, B2)

Claims (2)

[Claims] 1. A conductive green paste is applied to a dielectric green sheet, and a plurality of internal electrode patterns are printed vertically and horizontally to form a pattern group, which are punched to a predetermined size for each pattern group, laminated and crimped. In the method for manufacturing a laminated ceramic capacitor which is then fired, a pattern group having the same arrangement in which the internal electrode patterns are shifted by half a pitch every other row,
A method for manufacturing a monolithic ceramic capacitor, which comprises printing and arranging on a green sheet using the same stencil, punching by shifting the pattern groups alternately by odd-numbered columns, and sequentially laminating them. 2. A conductive green paste is applied on a dielectric green sheet, and a plurality of internal electrode patterns are printed vertically and horizontally to form a pattern group, which are punched into a predetermined size for each pattern group, laminated and crimped. In the method for manufacturing a laminated ceramic capacitor which is then fired, a pattern group having the same arrangement in which the internal electrode patterns are shifted by half a pitch every other row,
All of them are characterized by using the same stencil to print by arranging them on the green sheet while shifting them by an odd number of columns of the same pattern alternately, punching out the pattern groups without shifting in the column direction, and stacking them sequentially. Manufacturing method of multilayer ceramic capacitor.