JPH0384993A - Method of dividing ceramic laminate - Google Patents

Abstract

PURPOSE:To divide a ceramic laminate with good dimensional accuracy by fixing a ceramic laminate with its end sheet down on a support, making cuts from the top sheet of the laminate to part of the end sheet, taking the laminate off the support and heating it to remove binder, and subjecting it to a barrel treatment. CONSTITUTION:A plurality of inner electrodes are printed on first ceramic green sheets by a screen printing method using Ni-based conductive paste. These green sheets are laminated and sandwiched by first green sheets on its top and bottom to form a laminate 1. The first green sheets have no inner electrode printed. A second green sheet 2 (having a smaller binder content) is attached to one side of the laminate 1 by pressure to form a ceramic laminate for sintering. The laminate (1+2) is seated on a support with the second green sheet 2 at the bottom and fixed by suction via through holes 4. A rotating blade is operated to make cuts 5 to about 2/3 of the depth of the second green sheet 2. Then, the laminate is heated to remove binder and treated by a rotating barrel so that it is divided into laminated ceramic capacitors of individual sizes.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for dividing a ceramic laminate, which divides a large-area ceramic laminate in which a plurality of ceramic laminates are collectively formed into individual ceramic laminates. Regarding the method.

[Prior art] Ceramic laminates used in the electronics industry include, for example, multilayer ceramic capacitors and multilayer composite devices, but these ceramic laminates are becoming smaller and smaller in line with the trend toward lighter, thinner, and smaller electronic components. As a result, high dimensional accuracy is required.

In a conventional method for manufacturing a ceramic laminate, a conductive paste is printed on an unfired ceramic sheet by screen printing or the like to form a plurality of conductors, a plurality of internal electrodes, and the like. A predetermined number of these sheets are piled up and pressed together to form a ceramic laminate. When dividing this ceramic laminate into individual ceramic composite elements or ceramic multilayer capacitors, etc., the laminate is first fixed to a support with an adhesive such as adhesive tape or paraffin.

Generally, an adhesive tape is used, and an adhesive tape with an appropriate strength is selected in consideration of the adhesive strength of the adhesive tape and the peelability after cutting.

There are two main ways to divide a laminate:

The first method is to place a thin rectangular blade with a length equal to or longer than the length of the side of the laminate in the cutting direction in a predetermined position vertically, and press the cutting edge against the laminate to cut it. be. This is a method of cutting by repeatedly moving the position of the blade and pushing the blade in the same way, and is effective when cutting relatively thin laminates. However, when the laminate becomes somewhat thick, the blade escapes when cutting, making it impossible to cut perpendicular to the board surface, resulting in slanted cut surfaces and trapezoidal laminates, resulting in dimensional accuracy. It has the disadvantage that it becomes worse. Therefore, the first method can be used only when the thickness of the laminate is such that it does not become trapezoidal, that is, when manufacturing a thin laminate.

In the second method, as in the first method, a laminated plate fixed to a support is rotated by a rotary blade consisting of a rotatable disc with a blade formed on the peripheral edge, and the cutting edge is brought into contact with the laminated plate. In this method, the laminate is divided by moving the disk vertically by a depth corresponding to the thickness of the laminate.

According to this method, unlike the first method, the cut surface is perpendicular to the board surface without being restricted by the thickness of the laminate, so the dimensions can be adjusted from thin laminates to relatively thick laminates. The second method is widely used these days as a method for dividing most ceramic laminates because it allows for accurate cutting.

[Problems to be Solved by the Invention] However, as ceramic laminates become smaller, the floor area of each ceramic laminate becomes smaller and the adhesion force to the support base becomes smaller. To become
When cutting a ceramic laminate with a rotating blade, there is a problem in that the individual ceramic laminates that are created by being divided may scatter or become misaligned, resulting in a change in shape or size.

[Means for Solving the Problems] As a means for solving the above problems, a method for dividing a ceramic laminate as described below was developed. That is, in a method of dividing an unfired ceramic laminate into a plurality of small laminates into a plurality of small laminates, a plurality of unfired ceramic sheets containing ceramic raw material powder and a binder are laminated and pressed together. At least one end sheet of the plate is composed of a ceramic sheet using a binder different from the binder contained in the ceramic sheet constituting the main body of the ceramic laminate, or a ceramic sheet with a different binder content, and the ceramic laminate is fixed on a support with the end sheet facing down, a cut groove is formed from the main sheet side of the ceramic laminate to a depth reaching a part of the end sheet, and then the laminate is removed from the support. This is a method for dividing a ceramic laminate, which is characterized in that the ceramic laminate is divided into individual small laminates by peeling, heat treatment, removing the binder, and barrel treatment.

[Function] According to the present invention, the sheet constituting the end layer of the ceramic laminate is not divided into pieces by cutting and is fixed as one piece on the support base, so the adhesive strength is large.
There is no chance of individual laminates scattering during the step in which the ceramic laminate is cut.

The sheet constituting the end layer of the ceramic laminate contains a binder different from the binder in the ceramic sheet constituting the main body of the laminate, or a binder in a content different from that of the binder in the ceramic sheet constituting the main body of the laminate.

In other words, the binder in the end sheet is of a composition that is more easily decomposed or scattered by heating than the binder in the ceramic sheet constituting the main body of the ceramic laminate, or its content is relatively significantly higher. Because of this, when heated, the binder scatters more easily than the binder in the sheet that forms the main body of the ceramic laminate, or the amount remaining in the ceramic sheet after heating is very small. The laminate can therefore be easily divided by subsequent barrel processing. This is because the ceramic sheet forming the end layer is more likely to disintegrate than the main sheet due to the above-mentioned reasons.

[Example 1] A dielectric ceramic raw material powder containing barium titanate as the main component and a binder solution containing acrylic resin as the main component were prepared.

First, a dielectric ceramic slurry was prepared by mixing 1.000 g of the dielectric ceramic raw material powder and 1.000 g of a binder solution containing 98 g of resin. Next, the slurry was coated on a polyethylene terephthalate film (hereinafter referred to as PET) using a reverse coater for 3
After coating to a thickness of 0m and drying at a temperature of 100℃, PE
A ceramic green sheet of 120 vu* square was peeled off from the T, and this was used as the first ceramic green sheet constituting the main body of the ceramic laminate.

Next, 1.000 g of the dielectric ceramic raw material powder and 1,000 g of a binder solution containing 80 g of resin were mixed to prepare a dielectric ceramic slurry. The slurry was coated on PET to a thickness of 80 mm using a reverse coater, dried at a temperature of 0.0 °C, and then peeled off from the PET to form a 120 mm square ceramic green sheet, which was then formed into a ceramic laminate. The second part of
It was used as a ceramic green sheet.

A plurality of internal electrodes are screen-printed on a first ceramic green sheet using a conductive paste containing NL as a main component, and 60 sheets of this are stacked, and a first green sheet with no internal electrodes printed above and below it. A laminate 1 is made by stacking 5 sheets each, and a second green sheet (a sheet with a lower binder ratio) 2 is superimposed on one end surface and crimped.
A green ceramic laminate was constructed (see Figure 1).

Next, a cutting support table (cut table 3 in FIG. 1) which has a through hole (suction hole 4 in FIG. 1) and is capable of holding an article thereon by suction through the through hole is installed. Place the laminate (1+2) on its second green sheet (first
The sheet 2) in the figure was placed with its side facing down, and suction was applied from the through hole 4 to fix and hold the laminate on the support base.

While rotating the rotary blade in this state, move from the main sheet side of the laminate toward the support stand until the tip of the rotary blade reaches a depth of about 1/3 of the thickness of the second green sheet. The rotary blade was moved vertically to form a cut groove, leaving about 273 mm of the thickness of the second green sheet (see Figure 1).
(See (b), which is a partially enlarged view of a). This operation was repeated sequentially at predetermined groove intervals. After repeating the predetermined number of times, rotate the support stand 90 degrees, repeat the cutting operation in the same way, and cut 4.0 mm x 2. A plurality of kerfs were formed at centerline intervals to form a lattice pattern of lsn.

This was heated to 250° C. and held for 3 hours to perform a binder removal treatment, and was further subjected to a rotating barrel treatment. Barrel-processed multilayer ceramic capacitors were segmented into individual sizes.

Randomly select 50 multilayer ceramic capacitors obtained in this way, measure their dimensions with a micrometer, and calculate the average value (nu) and standard deviation (3σ) of the
Shown in the table.

[Example 2] Table 1 shows the results of the same procedure as in Example 1, except that the amount of resin in the binder solution for the second ceramic green sheet was 45 g instead of 80 g. It was shown to.

[Example 3] Table 1 shows the results of the same procedure as in Example 1, except that the amount of resin in the binder solution for the second ceramic green sheet was 30 g instead of 60 g. It was shown to.

[Example 4] Table 1 shows the results of the same procedure as in Example 1, except that the amount of resin in the binder solution for the second ceramic green sheet was 75 g instead of 80 g. It was shown to.

[Example 5] In Example 1, the binder solution for the second ceramic green sheet was replaced with a binder solution whose main component was a low molecular weight methacrylic resin instead of the binder solution whose main component was an acrylic resin. Except for this, the same procedure as in Example 1 was conducted, and the results are shown in Table 1.

[Comparative Example] In Example 1, the laminate l' from which the second ceramic green sheet 2 was removed was used, and this was fixed to the cutting table 3 with an adhesive film 2' (see Fig. 2(a)). Table 1 shows the results obtained in the same manner as in Example 1 except for the following. An enlarged view of the lower end of the kerf in this case is shown in FIG. 2(b).

As shown in the examples above, even when processed at the same temperature,
The amount of binder remaining in the second ceramic sheet is
It can be seen that the predicted effect can be obtained if the amount of binder is less than the amount of binder remaining in the first ceramic sheet.

(Margins below) Table [Effects of the Invention] According to the present invention, even when ceramic laminates are downsized and the floor area of each ceramic laminate becomes smaller, the bottom surface of the laminate remains integral and can be subdivided. Since the ceramic laminate is not oxidized, there is no decrease in adhesive strength, and when cutting the ceramic laminate with a rotating blade, the ceramic laminate does not scatter or become misaligned, allowing it to be divided with good shape and dimension accuracy. can do. Therefore, the present invention greatly contributes to improving dimensional accuracy and productivity.

FIG. 1 is an explanatory diagram showing a state in which grooves are formed in a ceramic laminate by the method of the present invention, and (a) is a side view;
(b) is an enlarged view of the lower end of the kerf shown in (a).

FIG. 2 is an explanatory view showing a state in which grooves are formed in a ceramic laminate by a conventional method, and (a) is a side view; (a) is a side view;
b) is an enlarged view of the lower end of the kerf shown in (a).

Explanation of symbols 1...Laminated body 1 of sheets with a normal binder ratio
′... Laminate 2... Sheet with a lower binder ratio 2'... Adhesive film 3... Cutting table 4... Suction hole 5... Cut groove

Claims (1)

[Claims] A plurality of unfired ceramic sheets containing ceramic raw material powder and a binder are laminated, but one unfired ceramic sheet placed at one end is of a different type from the binder contained in the other laminated sheets. A ceramic laminate containing a binder or the same type of binder but in a smaller amount than other sheets is crimped and integrated, and the resulting ceramic laminate is placed with the end arrangement sheet facing down. Fixed on a support stand, a rotary blade is moved vertically from above to form a predetermined number of kerf grooves in each predetermined direction with a depth that reaches a part of the end arrangement sheet but does not cut the end sheet, and then A method for dividing a ceramic laminate, comprising removing the laminate together with the uncut end placement sheet from the support, heat-treating to remove the binder, and then barreling to divide into individual laminates of predetermined dimensions. .