JP2000077254A - Manufacturing method of multilayer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a multilayer capacitor efficiently and with good yield by a stable method. SOLUTION: It is obtained by firing a multilayer body in which a plurality of ceramic green sheets are stacked. In a method for manufacturing a multilayer capacitor using a sintered body, a first pattern (pattern A) and a second pattern (pattern B) are formed on a carrier sheet made of thermoplastic plastic by using a conductive paste serving as an internal electrode as ink. To form a sheet-like pattern sheet A and a pattern sheet B printed thereon, the pattern sheet A and the pattern sheet B are alternately laminated with predetermined alignment, and a ceramic green sheet is interposed between each of the pattern sheets. Into a laminate, and the laminate is heated and pressed to form an organic layer in the carrier sheet and the conductive paste. A method for producing a multilayer capacitor in which a binder and a binder are burned out by heating and pressing, and then reduced and fired to form external electrodes, wherein the carrier sheet is a biaxially stretched film made of polyethylene terephthalate resin.

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 multilayer capacitor in which an external electrode is formed by sintering a laminate in which internal electrodes are precisely arranged between dielectrics.

[0002]

2. Description of the Related Art In a manufacturing process of a multilayer capacitor, an internal electrode is formed by printing a conductive paste on a thin ceramic green sheet, and the ceramic green sheet on which the internal electrode is formed is cut into a predetermined size. 2. Description of the Related Art A large number of sheets are laminated with the positions of electrodes aligned. However, since the ceramic green sheet is easily cut and has no elasticity, there are problems such as wrinkling of the ceramic green sheet and poor alignment accuracy of the internal electrodes during lamination. Various methods have been proposed as countermeasures. For example, a ceramic green sheet is temporarily attached to a carrier sheet, a hole for positioning is formed in the carrier sheet, a positioning pin is provided in a transfer head, and the holes for positioning are provided in subsequent steps such as transfer, printing, and lamination. A method has been proposed in which a positioning pin for receiving a positioning hole is provided in an apparatus used in each of the above-described steps using the positioning pin and the positioning pin is received, and the layers are stacked at a precise position (for example, Japanese Patent Application Laid-Open No. Hei 5-182589). In addition, various methods have been proposed for accurately adjusting the positions of the internal electrodes in the lamination.

As a conventional method of manufacturing a laminated electronic component, for example, in the case of a ceramic capacitor, a ceramic green sheet is placed on a support, and a conductive paste is applied on a base sheet using a predetermined plate. The first pattern is printed and dried to form an internal electrode (the printing and drying of a conductive paste to form an internal electrode is the same hereinafter),
Furthermore, a ceramic green sheet is laminated thereon, and the conductive paste is printed again by the second pattern shifted from the pattern, and the next print pattern is printed by the same plate as the first pattern. Then, printing is performed according to the second pattern, and this printing operation is repeated to form a laminated body by laminating a large number of ceramic green sheets, and then, so that the internal electrodes are exposed at the ends. After the laminate is punched into a predetermined area, it is fired, and an external electrode is provided on the cross section to produce a ceramic capacitor. Alternatively, a conductive paste is printed on a support, and a ceramic slurry is coated and dried on the support by a doctor blade method or the like to form a ceramic green sheet, and the formed ceramic green sheet is peeled from the support. Then, there is a method of transferring a conductive layer of the conductive paste to the ceramic green sheet. Then, the ceramic green sheet is peeled from the support and cut into a predetermined size at the same time, and is housed in a laminated frame. Next, the sheet is shifted by a predetermined size and cut into a predetermined size. There is a method in which a predetermined number of laminated bodies are stored as the second layer.

[0004]

However, the above-mentioned method using a support is performed by placing a green sheet on the support and temporarily attaching the green sheet, or by applying a ceramic slurry on the support by a doctor blade method or the like. A process such as a process of forming a ceramic green sheet by coating and drying is required. Therefore, an object of the present invention is to provide a method for manufacturing a multilayer capacitor efficiently and with a high yield by a stable method.

[0005]

According to a method for manufacturing a multilayer capacitor using a sintered body obtained by firing a multilayer body in which a plurality of ceramic green sheets are stacked, an internal electrode is provided on a carrier sheet made of thermoplastic plastic. Forming a sheet-like pattern sheet A and a pattern sheet B on which a first pattern (pattern A) and a second pattern (pattern B) are printed using a conductive paste as an ink;
The pattern sheet A and the pattern sheet B are alternately stacked with predetermined alignment, and a ceramic green sheet is inserted between the respective sheets of the pattern sheet to form a laminate, and the laminate is heated and pressed. A method for producing a multilayer capacitor in which the carrier sheet and an organic binder in a conductive paste are burned out by heating and pressing, and then reduced and fired to form external electrodes, wherein the carrier sheet is made of a polyethylene terephthalate resin. Including a stretched film.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a multilayer capacitor according to the present invention will be described below in more detail with reference to the drawings. FIG. 1 is an explanatory diagram of lamination of a carrier sheet and a green sheet in manufacturing the multilayer capacitor of the present invention. FIG. 2 shows a printed pattern A of a conductive paste, and FIG. 3 shows a printed pattern B of a conductive paste. FIG. 4 is an explanatory diagram showing a positional relationship between the pattern A and the pattern B, and shows a position on the (a) plane and a position on the cross section (b). FIG. 5 is a partially cutaway perspective view of the multilayer capacitor. In general, in the conventional method of printing a pattern on a green sheet using a conductive paste, the green sheet lacks dimensional stability, so that accurate lamination is difficult, and the green sheet is temporarily attached to a carrier sheet. A method of printing a pattern on the temporarily adhered green sheet and peeling off the carrier sheet before lamination was an inefficient method. The present inventors have studied various methods, and as a result, conventionally, printing of a conductive paste that has been printed on a green sheet is printed on a carrier sheet made of thermoplastic resin having dimensional stability, and in the lamination, the carrier A plurality of sheets are stacked, and a laminate formed by inserting a green sheet between the carrier sheets is heated and pressed, cut and baked, and further forming an external electrode, with stable workability, and
The inventors have found that a highly accurate multilayer capacitor can be obtained, and have completed the present invention.

That is, in the method of manufacturing a multilayer capacitor, conventionally, two patterns (pattern A and pattern B) which are shifted by a predetermined dimension on a green sheet using a conductive paste as ink are printed. By printing on the carrier sheet instead of the green sheet, the effect of stabilizing the formation of the pattern and subsequent steps is exhibited.

[0008] A plurality of patterns can be imposed on a printing plate. If the dimensional stability of the carrier sheet is good, even if many patterns are imposed, processing can be performed in steps following the printing step without causing a trouble such as misalignment, and the production efficiency is good. Although the number of impositions of the pattern provided on the printing plate shown in FIGS. 2 and 3 is 30 for imposition of 5 × 6 for explanation, in the case of actual production, for example, Many patterns (about 50 to 1,000 pieces) can be imposed to increase production efficiency. The positional relationship between the pattern A and the pattern B is such that, from the laminated body in a multi-faced state, the cutting marks for individual cutting are common to the patterns A and B, and when cutting is performed at the position of the cutting marks, The positional relationship is such that the internal electrodes are exposed at both ends as a multilayer capacitor. FIG. 4 (a)
It is a diagram for the explanation, the cutting marks provided at the time of printing of the pattern A and pattern B are common,
The pattern A and the pattern B are tentatively displayed in parallel, and FIG. 4B shows the positional relationship of the pattern on the cross section of the laminate. Cutting mark 3x1, 3x2
, 3x3 ... and 3y1, 3y2, 3y3 ...
By cutting in order, a chip-shaped laminate of a predetermined size exposed at both ends of the internal electrode can be obtained. By such cutting, the terminals of the pattern A and the pattern B are exposed at both ends.
In the above, a part of the pattern B may be included on the terminal side of the pattern A, but there is no particular problem in the performance of the multilayer capacitor.

As described above, printing is performed using the printing plate provided with the pattern A and the pattern B. In the present invention, first, in the printing unit, the carrier sheet is placed at a predetermined position with respect to the printing plate. And the pattern A shown in FIG. 2 is printed using the conductive paste as a printing ink. Next, in another printing unit or the same printing unit on which pattern A is printed, the plate is replaced, and FIG.
Is printed. The method of fixing the printing plate at a predetermined position with respect to the printing plate includes a method of providing positioning pins (hereinafter, referred to as positioning pins) on a printing table, and positioning holes ( The positioning hole and the pattern always reproduce a fixed position by fitting the positioning hole) into the positioning pin. The position of the positioning pin and the printing plate,
The pattern A and the pattern B, which are in a fixed positional relationship and form the internal electrodes to be printed, are designed to have a deviation of a dimension designed to form an electrode as a multilayer capacitor described later. . Further, a cutting mark indicating a cutting position when cutting the multi-faced pattern individually is provided at a common position for both the pattern A and the pattern B.

Therefore, the common cutting marks overlap in the lamination of the pattern sheet 1A and the pattern sheet 1B. As a specific method of the positioning, for example, in the case of single-sheet printing, a positioning hole is provided in advance on a carrier sheet, while a printing table is provided with a positioning pin corresponding to the positioning hole, and the pin is provided on the pin. Printing is performed by fitting the positioning holes. On the other hand, positioning pins for lamination are also provided at the same position as the positioning pins provided on the printing table on the laminating table used in the laminating step.

In the present invention, when the conductive paste 4 is printed on the carrier sheet 1 as ink, the carrier sheet 1 may be in the form of a roll or a single sheet. In the case where the conductive paste 4 is printed on the roll-shaped carrier sheet 1, after printing, the carrier sheet 1 on which the pattern A or the pattern B is printed is sheeted (made into sheets), and at the same time, the printed pattern sheet is printed. By detecting the cutting marks and providing the positioning holes 7 at predetermined positions, it is possible to form a laminated body in which the cutting marks are overlapped in the same manner as the positioning in printing on the carrier sheet 1 of the sheet. Becomes

Next, the lamination in the method for manufacturing a multilayer capacitor according to the present invention will be described. As aforementioned,
A carrier sheet on which a large number of the patterns A and B are printed and a green sheet having the same size as the carrier sheet used for printing are prepared. The pattern A and the pattern B of the printed carrier sheet are alternately laminated. In the lamination, it is preferable that the fixing position (cutting position) of the pattern A and the pattern B in the printing is the same, and the position fixing method used in the printing is also used in the lamination. As shown in FIG. 1A, first, two or three green sheets 2 are placed on a lamination table 10, a pattern sheet A, a green sheet 2, a pattern sheet B, and a green sheet 2. The pattern sheet A is laminated. Thereafter, the green sheets 2 are repeatedly laminated in the same manner, and finally, two or three green sheets 2 are laminated on the pattern sheet B. At this time, the positioning pins 1 are attached to the lamination table 10 so that the pattern A and the pattern B are located at predetermined predetermined positions.
1 (in the case illustrated in FIG. 1A, four pins are provided at the four corners of the stacking table), and the carrier sheet is provided with positioning holes 7 to be fitted into positioning pins 11 provided on the stacking table. Is provided. Also, the positioning holes 7 may or may not be provided in the green sheet 2 inserted between the carrier sheets. It is desirable that the positioning hole 7 is also provided in the green sheet 2.

Next, the lamination in the method for manufacturing a multilayer capacitor of the present invention will be described. As for the positioning at the time of lamination, as shown in FIG. 1A, for example, fitting of positioning holes 7 provided on the pattern sheets 1A and 1B and the green sheet 2 with positioning pins 11 provided on the lamination base 10 is performed. The order of lamination is as follows: the green sheet 2, the pattern sheet 1A, the green sheet 2, the pattern sheet 1B, the green sheet 2, and the pattern sheet 1A are repeatedly laminated first, and finally, The green sheet 2 is laminated. As described above, by stacking the positioning holes 11 in the positioning pins 11 for stacking while determining the position, the stacking can be performed with the cut marks overlapping. First, a laminate may be formed by laminating only the pattern sheets, and then the green sheets 2 may be inserted between the respective pattern sheets of the laminate. ,
They may be laminated like a pattern sheet.

At the time of the above-mentioned lamination, a plurality of green sheets to be laminated at the beginning and the end are desirably used as a housing for a laminated capacitor which is a final product.

Further, when laminating, it is necessary to make the thickness uniform over the entire area where the pattern sheet and the green sheet are laminated. If the laminated body has uneven thickness, in the laminating step of the laminated body to be described later, a deviation occurs in a pattern to be an internal electrode, and in cutting, the exposure of the internal electrode becomes inappropriate, and as a result, as a laminated capacitor, , The capacity may be insufficient. As shown in FIG.
If there is a green sheet all over the pattern sheet,
Although there is no concern about the occurrence of the thickness unevenness, if the green sheet is inserted only into a necessary portion, that is, a portion used as a multilayer capacitor, the thickness due to lamination is unevenly distributed as described above. As a countermeasure, in the present invention, for example, as shown in FIG. 1 (b), by interposing a spacer 8 in the positioning hole portion, the thickness of the entire laminated body becomes uniform. Although not shown, the spacer 8 may have a shape extending over four sides of the outer edge of the carrier film. If the spacer is bitten over the entire peripheral portion, the thickness at the time of lamination becomes uniform over the entire region of the carrier sheet, so that the displacement during the lamination can be prevented. In this way, the number of carrier sheets is 40 to 1000, preferably 40 to 40.
There are no laminates.

By applying heat and pressure to the obtained laminated body and pressing the laminated body, voids between the layers of the laminated body are eliminated, and the organic binder component in the carrier sheet and the conductive paste is burned off. The crimping condition is 150
~ 400 ° C, 10 ~ 50Kg / cm ² , 4 ~ 10 minutes.

The laminate pressed by heating under pressure is cut, and the cutting is performed on a printing plate for printing the conductive paste on a carrier sheet, at the same time as the pattern of the conductive paste, indicating the cutting position of the pattern. Vertical and horizontal cutting marks, for example, 3x1, 3x2, 3x3, 3 in FIGS.
x4 ..., 3y1, 3y2, 3y3, 3y4 ...,
Is printed, and the cutting mark is detected and cut vertically and horizontally to form a chip-shaped laminate in which the internal electrodes are alternately exposed on the end surface as a multilayer capacitor, as described above. it can. Incidentally, the respective cutting marks are common to both the pattern A and the pattern B,
When the printed carrier sheets are stacked, each cutting mark is set and made to be at the same position for all the sheets.

The chip-shaped laminate cut to the specified size is fired at 1000 to 1300 ° C. to convert the green sheet into a ceramic to form a dielectric.

An external electrode is formed at the end of the chip-shaped laminated body cut into a prescribed size obtained as described above. For example, a method of forming the external electrode is to form a base metal external electrode and perform reduction firing. After that, a method such as forming a silver external battery may be used. FIG. 5 shows an outline of the obtained multilayer capacitor.

Next, the materials used in the method for manufacturing a multilayer capacitor according to the present invention will be described. The green sheet used in the manufacturing method of the multilayer capacitor according to the present invention is an unfired sheet of ceramic formed into a thin plate, and is manufactured in a normal manufacturing method, that is, such as a ceramic raw material powder, an organic binder, a plasticizer, and an organic solvent. The mixed slurry formed into a sheet by a doctor blade method or a calendar method can be used.

In the laminate according to the present invention, a conductive paste is pattern-printed on a carrier sheet. As the carrier sheet, a sheet having good dimensional stability in the printing step and low elasticity is used. Specifically, a film or sheet made of a resin such as polyethylene terephthalate, polyvinyl butyral, methyl cellulose, and ethyl cellulose can be used. Carrier sheet thickness is about 5-100 μm, 10-40 μm
A thickness of about m is preferred.

In the multilayer capacitor according to the present invention,
The conductive paste used for pattern printing on the carrier sheet to form the internal electrodes is Ni, P
It is composed of a metal or alloy powder such as t, Ag-Pd, an organic binder and an organic solvent. As the organic binder, ethylene-vinyl acetate copolymer,
Various waxes, acrylic resins, and the like, and toluene, xylene, ethyl acetate, and the like can be used as the organic solvent. As a printing method of the conductive paste, gravure printing, letterpress printing, flexographic printing, silk screen printing, electrostatic printing, transfer printing, or the like can be used.

In the production of the multilayer capacitor according to the present invention, the number of laminated carrier sheets is about 40 to 1000, more preferably about 40 to 400. The present invention provides a ceramic green sheet obtained by printing an internal electrode pattern on a carrier sheet having good dimensional stability, positioning the printed pattern, and cutting the printed green sheet to a predetermined size between each layer of the printed carrier sheet. The method of inserting into a laminated body makes it possible to manufacture a multilayer capacitor with good workability and high accuracy.

[0024]

EXAMPLE A multilayer capacitor according to the present invention was prepared under the following conditions, and its effect was confirmed. As a carrier sheet in this example, a sheet of biaxially stretched polyethylene terephthalate film of 20 μm was prepared. By a die set punching device, a positioning hole having a diameter of 2.5φ is provided at each of the four corners of the sheet of the carrier sheet, and a printing table having a diameter of 2.45φ at a position to be fitted to the positioning hole provided in the carrier sheet. Four pins were provided. The position of the pin shall be a fixed position with respect to the printing plate, and the height shall be
3 mm. Pattern size: 2.0 x 4.0 mm The number of impositions is 20 x 20 = 400 pcs. Size of carrier sheet at the time of printing: 150 mm x 200 mm A conductive paste was printed by silk-screen printing. Printed and dried conductive layer thickness is 3μm ± 0.1μ
m. The conductive paste was prepared by mixing an Ag-Pd alloy powder, an ethylene-vinyl acetate copolymer and various waxes as a binder, and using toluene as a solvent to prepare a silk screen ink. Using.

As the green sheet, a ceramic green sheet was formed from a ceramic slurry mainly composed of a dielectric ceramic powder by a doctor blade molding method. The thickness of the obtained green sheet was 10 ± 1 μm. The size of the green sheet was the same as that of the carrier sheet used for printing, and four positioning holes were similarly provided by a die-set punching machine having positioning holes for the carrier sheet at four corners.

The stacking table was provided with four positioning pins having the same diameter at the same position as the printing table. However, the height of the positioning pins provided on the lamination table was 70 mm. As shown in FIG. 1A, the outline of the lamination is such that positioning holes provided in the green sheet and the carrier sheet are fitted to positioning pins provided in the lamination base. Specifically, first, three green sheets are put one on top of the other, and then the lamination in this order is repeated, such as pattern sheet A, green sheet, pattern sheet B, green sheet, pattern sheet A, and green sheet, A laminate of a total of 100 sheets (the number of carrier sheets) of 50 pattern sheets A and 50 pattern sheets B was prepared. Then, finally, a laminate was formed by stacking three green sheets in the same manner as the first.

Next, the laminate is pressurized at a pressure of 15 kg / cm ² and heated in a furnace at a temperature of 350 ° C. for 10 minutes to burn off the carrier sheet and the organic binder which is a component of the conductive paste. Then, the conductive layer was transferred to the green sheet.

Next, the crimped laminate was cut to obtain a chip-shaped laminate of a prescribed size. In the cutting, a chip-shaped laminated body was obtained by detecting a cutting mark provided at the same time as pattern printing in printing and cutting the sheet vertically and horizontally. The end face of the conductive layer of the pattern A was exposed on one end face of the chip-shaped laminate, and the end face of the conductive layer of the pattern B was exposed on the opposite end face.

A base metal external electrode is formed at the end of the chip-shaped laminate having a prescribed size obtained as described above, and 1150
The calcination was performed in a mixed gas of N ₂ and H ₂ at ℃. By performing reduction firing, a silver external battery was formed to obtain a multilayer capacitor.

The obtained multilayer capacitor had good performance without any displacement of the internal electrodes.

[0031]

According to the present invention, since printing is performed on a carrier sheet having excellent dimensional stability, the pattern accuracy of the internal electrodes is extremely high, and a high-quality multilayer capacitor can be produced with good yield. According to the method for manufacturing a laminated electronic component of the present invention, compared to the method of forming a conductive paste on a green sheet, the problem of shrinkage due to heating of the green sheet for drying the paste is eliminated, and the internal electrode is removed. As for the positional deviation due to lamination in the step of laminating a plurality of formed green sheets, a lamination method free from occurrence was obtained. In addition, a method for manufacturing a multilayer capacitor having good workability and accuracy can be achieved without requiring a step of temporarily attaching a green sheet to a support or a step of forming a green sheet on the support.

[Brief description of the drawings]

FIG. 1 is an explanatory view of lamination of a carrier sheet and a green sheet in manufacturing a multilayer capacitor of the present invention.

FIG. 2 is a printed pattern A of a conductive paste.

FIG. 3 is a printed pattern B of a conductive paste.

FIGS. 4A and 4B are explanatory diagrams showing a positional relationship between a pattern A and a pattern B, wherein FIG.

FIG. 5 is a partially cutaway perspective view of the multilayer capacitor.

[Explanation of symbols]

 S Multilayer capacitor A, B Print pattern of conductive paste 1 Carrier sheet 1A, 1B Pattern sheet 2 Green sheet 3x, 3y Cutting mark 4 Conductive paste or internal electrode 5 Dielectric 6 External electrode 7 Positioning hole 8 Spacer 10 Stacking board 11 Positioning pin

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 5E001 AB03 AC10 AF06 AH01 AH09 AJ01 AJ02 5E082 AA01 AB03 BC38 BC40 EE04 EE23 EE35 FG06 FG26 FG54 GG10 GG11 GG28 JJ03 JJ12 JJ23 LL01 LL02 LL03 MM21 MM22 MM21MM

Claims (2)

[Claims] 1. A method of manufacturing a multilayer capacitor using a sintered body obtained by firing a laminate in which a plurality of ceramic green sheets are laminated, wherein a conductive sheet serving as an internal electrode is formed on a carrier sheet made of thermoplastic plastic. A sheet-shaped pattern sheet A and a pattern sheet B are formed by printing two patterns, a first pattern (pattern A) and a second pattern (pattern B), using the paste as ink. The sheets B are alternately laminated with predetermined alignment, and a ceramic green sheet is inserted between the sheets of the pattern sheet to form a laminate. The laminate is heated and pressed to form the carrier sheet and the conductive sheet. The organic binder in the paste is burned off by heating and pressing, and then reduced and fired to form external electrodes. Manufacturing method of a multilayer capacitor. 2. The method according to claim 1, wherein the carrier sheet is a biaxially stretched film made of polyethylene terephthalate resin.