JP2001167972A - Ceramic green sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic green sheet with which the problem caused by frictional electrification and release electrification, etc., generated in the manufacturing stage is solved. SOLUTION: In this ceramic green sheet on the surface of which a circuit pattern is formed, a surface resistivity adjustment layer 2 is provided on a surface, on which the circuit pattern is formed, of the ceramic green sheet 1, and the sheet resistivity is made not to exceed 9×1012 (Ω/(square)). The adjustment layer 2 is constituted by a water-soluble binder layer and a layer containing not more than 10 wt.% of inorganic matter or antistatic additives, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic green sheet used for a multilayer ceramic capacitor, a ceramic multilayer substrate, and the like.

[0002]

2. Description of the Related Art Conventionally, there is a method called a lamination method as one of methods for manufacturing a multilayer substrate. This method includes the steps of forming a ceramic green sheet, cutting to a predetermined size, forming a conductive hole, filling a conductive paste into the conductive hole, printing a wiring using a screen mask, laminating a predetermined number of sheets, pressing and firing. .

[0003]

In these steps, for example, when a conductive paste is filled or screen printing is performed, the ceramic green sheet is indirectly rubbed with a rubber called a squeegee through a screen mask.
Alternatively, since the film lining the ceramic green sheet is directly rubbed, the ceramic green sheet tends to be triboelectrically charged.

Further, in each step, the finished ceramic green sheets are stored in an overlapping manner, so that peeling charging occurs each time the ceramic green sheets are separated one by one in the next step. The static electricity generated at this time impairs the transportability of the ceramic green sheet and causes a reduction in the equipment operation rate.

Further, in the sheet laminating method, there is a method in which the ceramic green sheet is handled in a state of being backed with a film until immediately before lamination. In this method, when the laminating film and the ceramic green sheet are peeled off at the time of lamination, they are charged by peeling. Since the charging polarity of the already laminated ceramic green sheets and the charging polarity of the peeled ceramic green sheets to be laminated from now on are the same, the ceramic green sheets repel each other and the adhesion is impaired, It may cause lamination displacement.

To solve these problems, there is a method in which an antistatic agent is contained in a slurry for forming a ceramic green sheet. In this case, a large amount of the antistatic agent is added to reduce the surface resistivity. If too long, the slurry gels and the strength of the formed ceramic green sheet decreases.

Accordingly, an object of the present invention is to provide a ceramic green sheet capable of solving the problems caused by frictional charging and peeling charging occurring during the production stage without causing gelation of the slurry or reduction in strength after molding. .

[0008]

According to a first aspect of the present invention, there is provided a ceramic green sheet having a circuit pattern formed on a surface thereof, wherein a surface resistivity adjusting layer is formed on a surface on which the circuit pattern is formed. And a ceramic green sheet characterized by having a surface resistivity of 9 × 10 ¹² (Ω / □) or less.

Generally, the surface resistivity of a ceramic green sheet is greater than 1 × 10 ¹³ . For this reason, the ceramic green sheets are temporarily frictionally charged at the stage of manufacturing a multilayer ceramic capacitor or a ceramic multilayer substrate, for example, at the time of screen printing, separating the stacked ceramic green sheets one by one, or peeling off the backing film. And peeling electrification occurs. However, in the present invention, a surface resistivity adjusting layer is provided to adjust the surface resistivity of the ceramic green sheet to 9 × 10 ¹² (Ω / □) or less.
The generated charges can be leaked in a short time. Therefore, problems due to frictional charging and peeling charging can be solved. In the present invention, a large amount of an antistatic agent is not contained in the slurry, but the surface resistivity adjusting layer may be provided after the formation of the ceramic green sheet. It is possible to obtain a ceramic green sheet whose surface resistivity is adjusted to be low without causing a decrease.
Therefore, when a multilayer substrate or multilayer capacitor is manufactured using such a ceramic green sheet, it is possible to manufacture a high-quality multilayer substrate or multilayer capacitor at low cost without lowering the equipment operation rate or causing a lamination shift. it can.

The surface resistivity adjusting layer may be a water-soluble binder layer. In this case, since the water-soluble binder has hygroscopicity, the resistivity is reduced by moisture, and the proper resistivity can be maintained. Further, the surface resistivity adjusting layer may be an inorganic-containing layer of 10% by weight or less. As the content of the inorganic substance increases, the surface resistivity can be reduced. However, when the content exceeds 10% by weight, the electrical characteristics of the obtained multilayer substrate are deteriorated. Further, the surface resistivity adjusting layer may be an antistatic agent-containing layer. As the antistatic agent, any type of antistatic agent such as anionic, cationic and nonionic may be used.

In recent years, an electrophotographic method has been proposed in place of a screen printing method for forming a circuit pattern on a ceramic green sheet. In the transfer step of the electrophotographic method, after charging the ceramic green sheet, the ceramic green sheet is brought into close contact with the photoreceptor, and the obtained chargeable powder image for circuit formation is transferred onto the photoreceptor. After the transfer, the photoreceptor and the ceramic green sheet are separated. At this time, if the surface resistivity of the ceramic green sheet is 1 × 10 ¹³ (Ω / □) or more, peeling discharge occurs at the time of separation, and a remarkable circuit-like shape is formed. The printed figures are disturbed. Therefore, it is desirable that the surface resistivity of the ceramic green sheet is adjusted to 1 × 10 ^{9 to} 9 × 10 ¹² (Ω / □) by providing a surface resistivity adjusting layer. That is, the surface resistivity is 9 × 10 ¹² (Ω /
□) Because of the following adjustments, good transfer can be achieved without causing peeling discharge between the photoreceptor and the ceramic green sheet. However, 9 × 10 ⁸ (Ω / □)
In the following, the electric charge easily leaks, the electric field intensity required for transfer cannot be obtained, and transfer omission is likely to occur.
It has been adjusted to more than ⁰⁹ (Ω / □).

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a process chart of an example of a method for manufacturing a ceramic multilayer substrate using ceramic green sheets according to the present invention. First, a ceramic slurry is prepared (step S1). Next, as shown in FIG. 2A, the ceramic slurry is formed into a sheet on the carrier film 3 to obtain a ceramic green sheet 1 (step S2). Specific sheet forming methods include a doctor blade method, a comma coater method, and a reverse roll coater method. Next, as shown in FIG. 2B, a surface resistivity adjusting layer 2 is formed in a thin film shape on the surface of the ceramic green sheet 1 formed on the carrier film 3 on which the circuit pattern is formed, and the ceramic green sheet is formed. The surface resistivity of No. 1 is adjusted to 9 × 10 ¹² (Ω / □) or less (step S3). Examples of the surface resistivity adjusting layer 2 include a water-soluble binder layer, an inorganic substance-containing layer, and an antistatic agent-containing layer described later. Next, the formed ceramic green sheet 1 is cut into a predetermined size (step S4). Next, a conduction hole is formed in the cut sheet using mechanical punching, laser punching, or the like (step S5).
Next, the formed conductive holes are filled with a conductive paste by using a screen printing method or the like (step S6). next,
A circuit pattern is formed on the ceramic green sheet using a screen printing method, an electrophotographic method, or the like (Step S7). Next, the ceramic green sheet on which the circuit pattern is formed is peeled off from the carrier film and laminated (step S8). Next, the laminated ceramic green sheets are pressed (step S9). Finally, the laminated ceramic green sheets are fired to obtain a multilayer substrate (step S10).

In the above process, when the conductive hole is filled with the conductive paste, when the circuit pattern is formed on the ceramic green sheet, or when the carrier film is peeled off, the ceramic green sheet is temporarily charged or peeled off. Although triboelectric charging occurs, a surface resistivity adjusting layer is formed on the surface of the ceramic green sheet to reduce the surface resistivity to 9 × 10 ¹²
(Ω / □) or less, the generated charges can be leaked in a short time,
Problems such as disturbance of the circuit pattern can be solved.

Various methods are conceivable for forming the surface resistivity adjusting layer 2 as described below, but are not limited to any one of the methods. In the water-soluble binder layer or the inorganic-containing layer, after the ceramic green sheet is dried,
It may be formed using a known sheet forming method, or may be cut into a card shape and then printed by screen printing or the like.
The antistatic layer may be formed by a known method such as a spray method. Further, the thickness of the surface resistivity adjusting layer of any of the above-mentioned forms is not limited. However, in order to prevent peeling that occurs in the process of firing the ceramic green sheet laminate and decrease in the sintered density, it is desirable that the thickness be reduced. It is desirable that the thickness be as thin as possible so as to satisfy the surface resistivity.

The formation time of the surface resistivity adjusting layer may be any time before the step where charging of the ceramic green sheet becomes a problem. However, in the case of forming after cutting into a card shape, the ceramic green sheets are stacked and charged at the time of cutting, so that it is preferable to form before cutting into a card shape. Therefore, it is not limited to the step of forming the surface resistivity adjusting layer between the sheet forming step S2 and the cutting step S4 as shown in FIG. 1, and the step of forming the surface resistivity adjusting layer S3 as shown by the broken line in FIG. In the cutting step S
4 and the conductive hole forming step S5, the conductive material filling step S6
And the circuit pattern forming step S7, and may be performed at any stage between the circuit pattern forming step S7 and the laminating step S8. If the ceramic green sheet is not cut, the sheet forming step S2 and the conductive hole forming step S5, the conductive material filling step S6 and the circuit pattern forming step S7, and further, the circuit pattern forming step S7 A surface resistivity adjusting layer may be formed between and the laminating step S8.

In FIG. 2, the ceramic green sheet 1 is formed on the carrier film 3 and the surface resistivity adjusting layer 2 is formed on the surface thereof. However, as shown in FIG. A surface resistivity adjusting layer 2 may be formed on the surface of the sheet 1.

[0017]

EXAMPLES Various surface resistivity adjusting layers were formed on the surface of a ceramic green sheet, and the results of measurement of frictional charging, peeling charging, and peeling discharge at a transfer portion in electrophotography are shown below. Friction charge measurement method: Measure the voltage after rubbing the samples for 10 seconds. Peeling charge measurement method: Peel the ceramic green sheet and the carrier film, and measure the voltage after 5 seconds. None → ○ Missing at electrophotographic transfer unit: Yes → ×, No → ○

[Experimental Example 1] Surface resistivity adjusting layer: A layer having a water-soluble binder as a main component and a water-based emulsion type binder added to a thickness of 1 μm Ceramic green sheet: Ba-Si-Al-O-based ceramic 70 wt% 10 μm thick ceramic green sheet made of organic binder 30 wt% Carrier film: PET film 25 μm thick, surface resistivity 3 × 10 ¹³ Ω / □

[0019]

[Table 1]

[Experimental Example 2] Surface resistivity adjusting layer: A layer having a water-soluble binder as a main component and an aqueous emulsion type binder added thereto having a thickness of 10 μm.
Ceramic green sheet: A ceramic green sheet having a thickness of 300 μm and comprising 70 wt% of a Ba—Si—Al—O-based ceramic and 30 wt% of an organic binder Carrier film: a PET film having a thickness of 100 μm
Surface resistivity 8 × 10 ¹³ Ω / □

[0021]

[Table 2]

Experimental Example 3 Surface resistivity adjusting layer: A mixture of an anionic antistatic agent and water was formed to a thickness of 1 μm or less. Ceramic green sheet: 70 wt% of Ba—Si—Al—O ceramic, organic Ceramic green sheet with a binder of 30 wt% and a thickness of 10 μm Carrier film: PET film with a thickness of 25 μm, surface resistivity 3 × 10 ¹³ Ω / □

[0023]

[Table 3]

[Experimental Example 4] Surface resistivity adjusting layer: A mixture of an anionic antistatic agent and water was formed to a thickness of 1 μm or less. Ceramic green sheet: 70% by weight of Ba-Si-Al-O type ceramic, organic type Ceramic green sheet having a thickness of 300 μm and a binder of 30 wt% Carrier film: PET film having a thickness of 100 μm,
Surface resistivity 8 × 10 ¹³ Ω / □

[0025]

[Table 4]

[Experimental Example 5] Surface resistivity adjusting layer: An organic binder as a main component and a carbon-containing inorganic material formed to a thickness of 3 μm Ceramic green sheet: Ba-Si-Al-O-based ceramic 70 wt% 10 μm thick ceramic green sheet made of organic binder 30 wt% Carrier film: PET film 25 μm thick, surface resistivity 3 × 10 ¹³ Ω / □

[0027]

[Table 5]

[Experimental Example 6] Surface resistivity adjusting layer: A layer containing an organic binder as a main component and containing carbon as an inorganic substance was formed to a thickness of 7 μm. Ceramic green sheet: Ba-Si-Al-O-based ceramic 70 wt% , Organic binder 30 wt%, ceramic green sheet 300 μm thick Carrier film: PET film 100 μm thick,
Surface resistivity 8 × 10 ¹³ Ω / □

[0029]

[Table 6]

In the above experimental example, an example is shown in which the surface resistance of the ceramic green sheet is reduced without using an antistatic agent. An antistatic agent may be added to the slurry.

[0031]

As is apparent from the above description, according to the present invention, in the stage of manufacturing a multilayer substrate or a multilayer capacitor, frictional charging or peeling charging may temporarily occur on a ceramic green sheet. A surface resistivity adjusting layer is provided on the surface of the green sheet to make the surface resistivity 9 ×.
Since it is adjusted to 10 ¹² (Ω / □) or less, the generated charges can be leaked in a short time. Therefore, it is possible to manufacture a high-quality multilayer substrate or multilayer capacitor without causing any trouble such as conveyance failure, lamination displacement, and circuit disturbance due to frictional charging or peeling charging. Further, since it is sufficient to provide the surface resistance adjusting layer after molding the ceramic green sheet without including a large amount of the antistatic agent in the slurry, gelation of the slurry and reduction in strength of the ceramic green sheet do not occur. .

[Brief description of the drawings]

FIG. 1 is a flowchart showing a manufacturing process of a multilayer substrate.

FIG. 2 is a sectional view of an example of a ceramic green sheet according to the present invention.

FIG. 3 is a cross-sectional view of another example of the ceramic green sheet according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic green sheet 2 Surface resistivity adjustment layer 3 Carrier film

Claims (5)

[Claims] A ceramic having a circuit pattern formed on a surface thereof.
The table that forms the circuit pattern on the green sheet
A surface resistivity adjusting layer is provided on the surface, and the surface resistivity is 9 × 10 ¹²
(Ω / □)
Sheet. 2. The ceramic green sheet according to claim 1, wherein said surface resistivity adjusting layer is a water-soluble binder layer. 3. The ceramic green sheet according to claim 1, wherein the surface resistivity adjusting layer is a layer containing 10% by weight or less of an inorganic substance. 4. The ceramic green sheet according to claim 1, wherein said surface resistivity adjusting layer is an antistatic agent-containing layer. 5. A ceramic green sheet having a surface resistivity adjusting layer having a surface resistivity of 1 × 10
The ceramic green sheet according to claim 1, wherein the ceramic green sheet is adjusted to ^{9 to} 9 × 10 ¹² (Ω / □).