JPH07186119A - Production of laminated ceramic part - Google Patents

Abstract

PURPOSE:To enhance the printability of an internal electrode pattern by arranging an elastomer composed of rubber or a high molecular compd. to the rear surface of a laminate consisting of ceramic green sheets containing a ceramic green sheet having an internal electrode printed thereon to bond the ceramic green sheets under pressure. CONSTITUTION:The thickness of an internal electrode 3 is absorbed into an elastomer 4 by arranging the elastomer 4 composed of rubber or a high molecular compd. placed on a base plate or a lower punch 5 to press the same and the pressure applied to the laminate l becomes uniform to enhance the mutual adhesiveness of green sheets 2. An internal electrode 3 is further printed on the upper surface of the pressure bonded laminate 1 and a new green sheet 2 is further laminated thereon and the whole is further pressed. Even when this operation is repeated, printing or pressure irregularity is not generated and uniform internal electrodes are always formed. The adhesiveness between the green sheets or between the green sheets and the internal electrodes 3 also becomes uniform and well and the stable laminate 1 is obtained.

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 monolithic ceramic component such as a monolithic ceramic capacitor, and more particularly to a method for laminating ceramic green sheets and a pressure bonding method in a temporary pressure bonding process.

[0002]

2. Description of the Related Art In manufacturing a monolithic ceramic component, for example, a monolithic ceramic capacitor, a required number of layers of ceramic green sheets having internal electrode patterns printed with a conductive paste are laminated, pressed by a pressing machine, and temporarily press-bonded. The multilayer capacitor body is formed by cutting the product into a predetermined size and firing it. In this temporary pressure bonding step, a large number of layers of ceramic green sheets are adhered to each other by pressure to form a laminated body.

In such a temporary press-bonding method, (1) a ceramic green sheet on which internal electrodes are printed and a ceramic green sheet on which the internal electrodes are not printed are laminated in a required number of layers, and a press machine is pressed at a time. Or (2) printing internal electrodes on a ceramic green sheet placed on a base plate, stacking a new ceramic green sheet on this, and temporarily press-bonding by pressing,
There is a method in which printing of internal electrodes, stacking of a new green sheet, and temporary press bonding by pressing are repeated to obtain a laminate having a predetermined number of layers. Then, in any of the temporary pressure bonding methods, when the number of layers of the internal electrodes printed on a given green sheet increases, a difference occurs in the thickness of the laminated body between the printed portion and the non-printed portion of the internal electrodes. There is a problem in that the pressure applied in the process becomes uneven, the adhesion of the green sheet deteriorates, and peeling occurs during firing.

As a countermeasure against this, Japanese Patent Publication No. Sho 62-8929 discloses a method of (1) above, in which ceramic green sheets printed with internal electrodes are laminated with a thickness of 30 to 500 μm on the ceramic green sheets. It is proposed that the metal or plastic thin plate of (1) be placed and pressure-bonded from above with a rubber sheet having a thickness of 1 to 20 mm.

Further, in JP-A-61-169211, the green sheet is laminated in the same manner as in the above (1),
Hot pressing using an upper punch having a convex curved surface on the pressing surface and a lower punch formed in a flat shape, and at least one of the pressing surfaces of the upper punch and the lower punch It has been proposed to attach an elastic member made of rubber or a polymer compound having elasticity.

[0006]

However, each of the above proposals has the following problems. That is, Japanese Patent Publication No. 62-89
In the method of Japanese Patent Publication No. 29, since a metal or plastic thin plate is interposed between the laminated green sheets and the rubber sheet placed on the laminated green sheets, it is difficult to apply pressure to the green sheets evenly, and in particular, the number of laminated green sheets. There was a problem in that the pressure unevenness increased as the number of times increased. Further, this metal or plastic thin plate is apt to be deformed or torn due to pressure, and it is difficult to set the optimum value of the thickness. Furthermore, since the unevenness corresponding to the thickness of the internal electrode is formed on the upper surface of the laminated body after the temporary pressure bonding, when applied to the method of (2) above,
There is also a problem that uneven printing occurs because the surface on which the internal electrode pattern is printed is not flat.

Further, in the method disclosed in Japanese Patent Laid-Open No. 61-169111, the upper surface of the laminated body is deformed into a concave shape due to the convex curved surface of the upper punch, and the pressing pressure is increased as the area of the green sheet increases. There is a problem in that it is difficult for the laminate to be evenly applied. Even when the convex surface of the upper punch is made of an elastic member, since the unevenness corresponding to the thickness of the internal electrode is formed on the upper surface of the laminated body after the temporary pressure bonding, the method of the above (2) is also used. There was also a problem that it could not be applied. These problems have not been solved by the method further proposed in the publication, in which an elastic member is attached around the laminated body of the lower punch.

The present invention has been made to solve the above problems, and in the process of stacking and temporarily bonding the ceramic green sheets in the manufacture of a multilayer ceramic component such as a multilayer ceramic capacitor, the unevenness of the temporary pressure bonding due to the presence or absence of the internal electrode. It is an object of the present invention to provide a method for manufacturing a laminated ceramic component, in which the adhesiveness of the ceramic green sheet is improved by reducing the above, and thereby peeling after sintering does not occur.

Further, according to the present invention, when a ceramic green sheet laminate is produced by repeating lamination of ceramic green sheets-temporary compression-printing of internal electrode pattern-lamination-temporary compression, the surface of the ceramic green sheet after the temporary compression bonding is repeated. It is an object of the present invention to provide a method for manufacturing a laminated ceramic component, which reduces the step due to the internal electrode and thereby improves the printability of the internal electrode pattern.

[0010]

According to the method of manufacturing a laminated ceramic component of the present invention, an elastic body made of rubber or a polymer compound is provided on the lower surface of a laminated body of ceramic green sheets including a ceramic green sheet on which internal electrodes are printed. It is characterized in that they are arranged and pressure-bonded.

In the method for manufacturing a laminated ceramic component of the present invention, a step of placing an elastic body made of rubber or a polymer compound on the lower surface of the laminated body of the ceramic green sheets and press-bonding the same is performed. The method is characterized by including a series of steps of repeating a step of printing internal electrodes on the upper surface of the laminate and a step of laminating a ceramic green sheet on the upper surface of the laminate on which the internal electrodes are printed.

[0012]

According to the method of manufacturing a monolithic ceramic component according to the first aspect of the present invention, when a green sheet laminate including a ceramic green sheet on which internal electrode patterns are printed is pressed and pressure-bonded, the lower surface of the green sheet laminate is pressed. Since an elastic body made of rubber or a high molecular compound is arranged and pressure-bonded, the step difference between the portion with internal electrode pattern and the portion without internal electrode pattern is absorbed by the elastic body, and the unevenness of pressure is eliminated. Bending and air bubbles between sheets are eliminated, and the adhesion of the green sheet is improved. Therefore, peeling does not occur after sintering.

Further, according to the method of manufacturing a laminated ceramic component according to the second aspect of the present invention, the step of pressure-compression bonding and the step of printing the internal electrodes on the surface of the pressure-compressed laminated body are alternately repeated. In this case, as in the above case, the unevenness of the pressurizing pressure is eliminated, and since the upper surface of the laminated body after pressure bonding has a flat surface with the same level as the surface of the upper punch, printing is performed when the internal electrode pattern is printed on the upper surface. Problems such as unevenness do not occur. Then, since the upper surface of the laminated body after the pressure bonding is a surface having no step regardless of the number of laminated green sheets,
Even under the same conditions, pressure bonding can be performed evenly. Therefore, the printing of the internal electrodes is further performed on the upper surface of the laminated body 1 thus pressure-bonded, the green sheet is newly laminated thereon, and the pressure-bonding is repeated again as a series of steps. Also in this case, a laminate having good adhesion between the laminates, which is free from uneven printing and uneven pressure, can be obtained.

[0014]

EXAMPLES The method for producing a monolithic ceramic component of the present invention will be described in detail below with reference to examples of monolithic ceramic capacitors. FIG. 1 is a schematic configuration sectional view showing an embodiment according to the manufacturing method of the present invention. FIG. 1 (a) shows a state before pressure-pressing a laminated body of ceramic green sheets,
FIG. 6B shows a state after pressure-bonding. In the figure, reference numeral 1 is a laminated body of ceramic green sheets, and this laminated body 1 is formed by laminating a predetermined number of layers of a ceramic green sheet 2 and internal electrodes 3. Reference numeral 4 denotes an elastic body made of rubber or a polymer compound, which is placed on the base plate or the lower punch shown by 5 and is arranged on the lower surface of the laminated body 1.
Then, the laminated body 1 is pressure-bonded to the base plate 5 by the upper punch 6 together with the elastic body 4. The arrow in the figure indicates the direction of movement of the upper punch 6.

As shown in FIG. 1A, the thickness of the laminated body at the portion where the internal electrodes 3 are printed is the sum of the thicknesses of the internal electrodes 3 and the green sheet 2. The thickness of the unprinted portion is the thickness of only the green sheet 2. Therefore, when the laminated body 1 is pressure-pressed from above and below only by the base plate 5 and the upper punch 6 which are rigid flat plates without disposing the elastic body 4, the pressure applied to the portion where the internal electrodes are printed becomes high, The pressure applied to the non-printed portion becomes low, pressure unevenness occurs, and the adhesiveness between the green sheets 2 deteriorates. On the other hand, as in the manufacturing method of the present invention, the elastic body 4 is arranged on the lower surface of the laminated body 1 and pressed, so that the internal electrode 3 is formed as shown in FIG.
The difference in thickness due to the presence or absence of is absorbed by the elastic body 4,
Since the pressure applied to the laminated body 1 becomes uniform, the adhesiveness between the green sheets 2 is improved. Moreover, since the upper surface of the laminated body 1 is directly pressed by the upper punch 6, the upper surface is as flat as the surface of the upper punch 6. Further, in the case where the internal electrode 3 is further printed on the upper surface of the laminated body 1 which is pressure-bonded in this manner, the green sheet 2 is newly laminated on the internal electrode 3, and the pressure-bonding is repeated again. In addition, uneven printing and uneven pressure are not generated, and a uniform internal electrode 3 is always formed, and the adhesiveness between the green sheets 2 or between the green sheet 2 and the internal electrode 3 is uniform and good. As a result, the laminated body 1 having stable quality is obtained.

Next, an example of a suitable structure for mounting the laminated body 1 on the base plate 5 via the elastic body 4 will be described with reference to FIG. FIG. 2 is a base plate 5 in the manufacturing method of the present invention.
3 is a schematic configuration cross-sectional view showing a configuration example of a stack 1 and a stack 1. In the figure, the same components as those in FIG. 1 are designated by the same reference numerals.
In the figure, in addition to the configuration shown in FIG. 1, an adhesive member 7 is interposed between the elastic body 4 and the base body 5 for fixing the elastic body 4 on the base plate 5, while the elastic body 4 and the laminated body 1 are arranged. A peeling member 8 having no adhesive force due to heating is interposed between and. By arranging the bonding member 7 in this way, the elastic body 4 is securely fixed on the base plate 5, and a series of steps of pressure bonding, printing of the internal electrodes 3 and stacking of the green sheets 2 are repeated. The positional deviation of the laminated body at that time can be prevented, and the positional accuracy of the laminated body 1 in the manufacturing process is improved. Further, by disposing the peeling member 8, when the laminated body 1 is separated from the elastic body 4 through the drying step after the temporary pressure bonding step, a part of the laminated body 1 is peeled off due to the adhesive force between them. It can be prevented.

For the ceramic green sheet 2 forming the laminated body 1, for example, for a capacitor, BaTiO 3 is used.
Dielectric materials such as ₃ , LaTiO ₃ , and composite perovskite Pb-based dielectrics are used. Further, for laminated chip coils, materials such as ferrite, titanium oxide, and alumina may be used, and for layer packages, materials such as alumina or ceramics such as alumina and silica mixed with glass may be used. it can. The thickness of these green sheets 2 is usually 15 to 75 μm, and about 1 to 120 layers are laminated. On the other hand, for the internal electrode 3, for a capacitor, for example, Pd, Ag-P
An electrode material such as d, Ag, Ni, or Pb is used, which is made into a paste with an organic solvent and a binder resin and printed by screen printing or transfer printing. Also,
As the other electrode material, the same electrode material as that for the above capacitor may be used for the chip coil, and Ag, Au, Cu, W, Mo or the like for the layer package.

The elastic body 4 absorbs a difference in thickness of the laminated body 1 due to the presence or absence of the internal electrode 3 when the laminated body 1 is pressure-bonded, and a uniform pressure is applied to the laminated body 1. A material that is not excessively deformed or damaged by is selected. Examples of such a material include rubber having an appropriate hardness having heat resistance and durability, or a polymer compound in the form of a sponge, a foamed sheet, a non-woven fabric, or the like. Examples of such rubber include urethane rubber, silicone rubber, fluororubber,
Neoprene rubber, butyl rubber, acrylic rubber, ethylene propylene rubber, butadiene rubber, isoprene rubber, natural rubber or the like can be used. Further, a urethane mat or the like may be used as the sponge of the polymer compound, and a foam release sheet (trade name: Riva Alpha Tape, etc.) may be used as the foam sheet.

The hardness of the elastic body 4 is 80 to 95 in terms of rubber hardness.
The range of degrees is preferable, and the range of 80 to 90 degrees is more preferable. When the rubber hardness is 80 degrees or less, the elastic body 4 is excessively deformed at the time of pressurization and the pressure on the laminated body 1 becomes insufficient, so that the adhesion between the green sheets 2 is deteriorated. In addition, since the elastic body 4 exhibits viscosity when being pressed, a part of the laminated body 1 may be peeled off when the laminated body 1 is separated from the elastic body 4 after the temporary pressure bonding. On the other hand, when the rubber hardness is 95 degrees or more, the difference in thickness of the laminated body 1 due to the presence or absence of the internal electrode 3 cannot be sufficiently absorbed, and it becomes difficult to apply a uniform pressure.

The size of the elastic body 4 is preferably within the range of about ± 2 mm from the outer periphery of the laminated body 1 and has substantially the same area as the laminated body 1. If it becomes larger than 2 mm from the outer periphery of the laminated body 1, when the upper punch 6 is lifted after pressure bonding, the periphery of the elastic body 4 is easily caught by the periphery of the laminated body 1 and the laminated body 1 is likely to be turned up. If it becomes too small, the lower surface of the laminate 1 cannot be completely covered at the time of pressure bonding, resulting in uneven pressure. The thickness of the elastic body 4 is appropriately selected in relation to the hardness, but is usually 0.5.
The range is preferably from 1.5 to 1.5 mm, more preferably from 0.8 to
A range of 1.0 mm is desirable. If the thickness is less than 0.5 mm, it is not possible to absorb the step difference of the laminated body 1 due to the presence or absence of the internal electrode. On the other hand, if the thickness is more than 1.5 mm, the elastic body 4 itself is excessively deformed and pressure unevenness easily occurs. As well as
After pressure bonding, the layers of the laminate 1 on the side closer to the elastic body 4 are likely to be turned over.

In order to fix the elastic body 4 on the base plate 5, as shown in FIG.
It is advisable to interpose the adhesive member 7 as shown in FIG. It is preferable to use, for example, a double-sided adhesive tape or an adhesive that bonds rubber and metal to the adhesive member 7 because the elastic body 4 and the base plate 5 can be reliably fixed.

As the peeling member 8 interposed between the elastic body 4 and the laminated body 1 as shown in FIG. 2, when a foam peelable sheet or the like is fixed on the elastic body 4 with wax, it is used. good. The size of the peeling member 8 is preferably the same as that of the laminate 1 or the elastic body 4, and the thickness thereof is preferably in the range of 50 to 300 μm. If the thickness is less than 50 μm, it may be broken at the time of pressurization or bubbles may be trapped between the elastic body 4 and the effect of the elastic body 4 may be impaired. On the other hand, if the thickness is more than 300 μm, the step absorption effect of the elastic body 4 may be obtained. Will be damaged.

When the elastic body 4 is repeatedly pressed in the temporary pressure bonding step, the laminated body 1 is left with traces due to deformation and gradually loses elasticity, so that the adhesiveness with the laminated body 1 is deteriorated. Come to do. In addition, dust, scraps, and the like from the laminated body 1 and the surroundings are caught, and uneven pressure is generated. Therefore, when those changes occur, it is desirable to replace them appropriately.

For the base plate or the lower punch 5, in addition to high hardness steel such as SKD (high hardness carbon steel for alloy tools) used in a usual press, SUS (stainless steel), alumina, zirconia, etc. are used. You can also use a ceramic plate,
In particular, the use of SKD11 is preferable because the hardness of the surface is increased by quenching and scratches are less likely to occur. On the other hand, the upper punch 6 has a press surface made of the above-mentioned materials usually used in order to enhance the peelability from the laminate 1.
It is preferable to attach a PET (polyethylene terephthalate) film whose surface is coated with silicon because the problem that the laminated body 1 after pressing adheres to the pressing surface and peels off can be reduced.

The pressure for the temporary pressure bonding in the manufacturing method of the present invention can be a pressure normally applied for manufacturing a ceramic laminate, but a gauge pressure of 40-18.
Within the range of 0 kgf / cm ² , the dielectric layers of the laminated body 1 can be reliably adhered to each other, the elastic body 4 is not excessively deformed, and the laminated body 1 is uniformly pressed, so that it is stable and stable. Crimping can be performed.

A detailed description will be given below based on specific examples. Example 1 A 16 μm thick ceramic green sheet containing BaTiO ₃ as a main material was used, and a Pd-based conductive paste was prepared as a screen printing paste for internal electrodes. On the other hand, as a press machine, HAPS (High Accurate Pr
inter & Stacker: High-precision printing laminating machine) is prepared, and the surface of the punch is coated with silicon to a thickness of 75
A PET film of μm is attached and the laminated body is placed S
On a base plate made of US430 and having a thickness of 2 mm, urethane rubber having a thickness of 1 mm and a hardness of 90 degrees and the same area as that of the green sheet is fixed with a double-sided adhesive tape, and a foam release sheet is used as a peeling member with carnauba wax. The fixed one was used.

First, a green sheet is supplied on the above-mentioned base plate, temporarily pressure-bonded at a pressure of 100 kgf / cm ² , dried in a drying oven, cooled, and then the green sheet is supplied again to perform temporary pressure-bonding. The above process was repeated to stack 10 layers of green sheets on which internal electrodes were not printed. Next, a green sheet is supplied on this, temporary pressure bonding is performed at a pressure of 40 kgf / cm ² , an internal electrode pattern is printed on it, dried in a drying oven, cooled, and then the green sheet is supplied again. The process of temporarily press-bonding and printing was repeated to laminate 68 layers of green sheets on which internal electrodes were printed. Then, supply the green sheet on it, 40
Repeat the process of performing temporary pressure bonding under a pressure of kgf / cm ² , drying in a drying oven, cooling, and then supplying a green sheet again to perform temporary pressure bonding. The layers were laminated to prepare a laminate A having a total of 88 layers.

In order to examine the laminated state inside the laminated body A produced in this way, the laminated body was cut to a predetermined size and fired, and then sandpaper (No. 1500) was used with a table-top grinder to remove internal electrodes from the end surface. Was further polished to a laminated portion, and further finish-polished with a diamond paste having a particle diameter of 1 μm, and its longitudinal section was observed using a stereoscopic microscope. As a result, in the laminate A, there is no problem in the adhesion between the sheets or between the sheet and the internal electrodes, and the printing of the internal electrodes is performed because the top surface of each sheet after pressing is flat. There was no unevenness, and it was a uniform and good laminated state.

[Example 2] Using the same ceramic green sheet and internal electrode paste as in [Example 1], 10 layers of the ceramic green sheet on which the internal electrodes are not printed and the printed ceramic green are formed on the same base plate. A total of 88 layers of 68 layers of sheets and 10 layers of ceramic green sheets on which internal electrodes were not printed were laminated. This was pressed at once with a pressure of 40 kgf / cm ² using the same press machine as in [Example 1] to perform temporary pressure bonding, and a laminate B having the same structure as the laminate A was produced. This laminate B
After being cut to a predetermined size and fired, it was polished in the same manner as in [Example 1], and its longitudinal section was observed to examine the internal laminated state. The upper surface of the laminated body was flat, and like the laminated body A, it was in a uniform and good laminated state.

[Example 3] SUS430 without an elastic body
A laminate C was produced in the same manner as in [Example 1] except that a base plate having a thickness of 2 mm was used. When the laminated state inside this laminated body C was examined in the same manner as in [Example 1], the portion where the internal electrodes were printed was strongly pressed, and the pressure at the non-printed portion was weakened, resulting in uneven pressure. As a result, there was a problem of adhesion such as floating in some sheets between sheets or between the sheets and the internal electrodes. In addition, since the upper surface of each sheet after pressing was not flat, there were some print irregularities of the internal electrodes, and the sheets were in a non-uniform laminated state as compared with the laminate A or the laminate B.

[Example 4] SUS430 without an elastic body
A laminated body D was prepared in the same manner as in [Example 1] except that the same elastic body and peeling member as in [Example 1] were fixed to the upper punch using a base plate having a thickness of 2 mm. When the laminated state inside this laminated body D was examined in the same manner as in [Example 1], the unevenness of the pressure applied due to the presence or absence of the internal electrodes did not occur. Therefore, the adhesion between the sheets or between the sheets and the internal electrodes was determined. No problem was seen. However, each sheet after pressing had a flat bottom surface, and unevenness was formed on the top surface due to the difference in thickness due to the presence or absence of internal electrodes. It can be seen that there are printing irregularities such as fading and bleeding.
Alternatively, compared to the laminated body B, the laminated state was non-uniform.

In each of the above embodiments, the base plate is SK.
Similar results were obtained when a 2 mm-thick plate made of D11 was used, or when a foam peelable sheet having a thickness of 0.8 mm and a hardness of 90 degrees was used as the elastic body.

[0033]

As described in detail above, according to the present invention,
In the process of stacking and temporarily bonding the ceramic green sheets, the unevenness of the temporary pressure bonding pressure due to the presence or absence of the internal electrode pattern is reduced to improve the adhesiveness of the ceramic green sheets, thereby preventing the peeling after sintering from occurring. A manufacturing method could be provided.

Further, according to the present invention, when the ceramic green sheet laminate is produced by repeating the lamination of the ceramic green sheets-temporary compression-printing of the internal electrode pattern-lamination-temporary compression, the ceramic after the temporary compression is formed. It has been possible to provide a method for manufacturing a laminated ceramic component that reduces a step due to the internal electrode pattern on the surface of the green sheet and thereby improves the printability of the internal electrode pattern.

Further, according to the present invention, it is possible to provide a ceramic laminated body including a laminated ceramic capacitor which can reduce unevenness in pressure bonding and printing unevenness in the temporary pressure bonding step and have stable characteristics after firing.

In the manufacturing method of the present invention, in addition to the capacitors described in the embodiments, coils, resistors, internal capacitors such as laminated chip coils and laminated piezoelectric elements formed by similarly laminating ceramic green sheets are used. The present invention can be similarly applied to various laminated ceramic parts having electrode patterns such as wirings, or ceramic layer packages.

[Brief description of drawings]

1 (a) and 1 (b) are schematic cross-sectional views showing an embodiment of the manufacturing method of the present invention.

FIG. 2 is a schematic cross-sectional view showing an embodiment of the manufacturing method of the present invention.

[Explanation of reference numerals] 1 ... Laminated body 2 ... Ceramic green sheet 3 ... Internal electrode 4 ... Elastic body 5 ... Base plate or lower punch 6 ... Upper punch 8 ... Peeling Parts

Claims (2)

[Claims] 1. A laminated ceramic component characterized in that an elastic body made of rubber or a polymer compound is arranged on the lower surface of a laminated body of ceramic green sheets including a ceramic green sheet on which internal electrodes are printed and pressure-bonded. Manufacturing method. 2. A step of arranging an elastic body made of rubber or a high molecular compound on the lower surface of the laminated body of ceramic green sheets and press-bonding it, and printing an internal electrode on the upper surface of the pressure-bonded laminated body. A method of manufacturing a laminated ceramic component, comprising a series of steps of repeating the steps and the step of laminating a ceramic green sheet on the upper surface of a laminated body on which internal electrodes are printed.