JPH05319943A - Production of baked laminate - Google Patents

Abstract

PURPOSE:To prevent the positional discrepancy, insufficient adhesive force and squeeze-out of sheet-forming material by laminating a ceramic green sheet to a step-compensation sheet having a hole with a squeeze-out prevention margin and baking the laminate to integrate the sheets. CONSTITUTION:Ceramic powder (e.g. alumina, zirconia or titania powder) to be baked in the baking of a ceramic green sheet 3 is formed together with a heat-sensitive fluidizing agent (e.g. carboxylic acid wax or paraffin wax) and a polymer binder (e.g. hydrocarbon polymer or acetal polymer) to obtain a step-compensation sheet 2. A hole is opened in each of the sheet 2 and the ceramic green sheet 3 and the hole 31 of the sheet 3 is made to be smaller than the hole 21 of the sheet 2. The holes 21, 31 are functioned as squeeze-out prevention margins. The sheet 3 is placed on a substrate film 1 interposing the sheet 2 therebetween in a state to coaxially place the hole 31 on the hole 21 and the sheets are integrated by baking.

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 laminated fired body suitable for forming a multilayer ceramic circuit board, a laminated ceramic capacitor and the like.

[0002]

2. Description of the Related Art While there is a demand for an efficient method of manufacturing a laminated fired body having a circuit pattern, the group to which the present inventors belong is first to apply a step compensation sheet and a ceramic green sheet in a laminated state. A method of producing a laminated fired body by firing a laminated body that has been subjected to perforating treatment for through holes and the like and imparting a conductor powder pattern has been proposed (Japanese Patent Application No. Hei 2-162258).

The above-mentioned proposed method has a method of laminating ceramic green sheets using a polymer adhesive or the like or using a binder in a self-sheet and firing the same, for example, It overcomes the problems that the conductor powder pattern is divided and that a gap is formed in the vicinity thereof, the positional deviation between layers in the obtained laminated fired body, insufficient adhesion, warpage, shrinkage, and the like.

However, in the above-mentioned proposed method, if the perforating process to be performed is a large hole such as a cavity portion, the step compensating sheet forming material is a hole when the ceramic green sheet is laminated through the subsequent step compensating sheet. It turned out that there was a problem that sticked out. The protrusion of the material for forming the step difference compensating sheet into the hole remains in the laminated fired body in which it is formed, and impedes the fitting of the mounting component or the like into the hole, making it impractical.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to preventing the conductor powder pattern from being divided and preventing the formation of gaps in the vicinity thereof.
Alternatively, while utilizing the advantages of the usage method of the step compensation sheet such as prevention of positional deviation between layers in the formed laminated fired body, avoidance of insufficient adhesion, and prevention of warpage and contraction, the step compensation sheet for the hole described above is provided. The object is to develop a method for manufacturing a laminated fired body that overcomes the protrusion of the forming material.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a step compensation sheet formed by holding a ceramic powder fired during firing of a ceramic green sheet with a heat-sensitive fluidizing agent and a polymer binder is perforated, and a ceramic A step of laminating a green sheet subjected to a perforating treatment smaller than the above on the base film through a step compensation sheet in correspondence with the perforated portions, and a ceramic green sheet on which a conductor powder pattern is formed as necessary. From the step of laminating and pressure-bonding with the step compensation sheet from which the above-mentioned base material film is removed through the conductor powder pattern surface, and the step of firing and integrating a predetermined number of ceramic green sheet laminates via the step compensation sheet. The present invention provides a method for manufacturing a laminated fired body, which is characterized by the following.

[0007]

By using the method of laminating the step compensation sheet and the ceramic green sheet that have been perforated in advance, the perforation portion formed on the step compensation sheet or the ceramic green sheet can be provided with a protrusion preventing margin so that the ceramic green sheet has a predetermined size. It is possible to prevent the forming material from protruding into the hole even if the step compensation sheet is flattened and the area is increased when a plurality of layers are stacked and pressed.

On the other hand, by laminating a predetermined number of ceramic green sheets having a conductor powder pattern through the step compensation sheet, the ceramic green sheet is deformed based on the ease of adjusting the step compensation sheet thickness and good uniformity. In addition, the conductor powder pattern can be easily and uniformly laminated without breaking the conductor powder pattern. Furthermore, it can be laminated in good adhesion without forming a gap at the interface through the conductor powder pattern, and peeling or misalignment occurs between the ceramic green sheets when processing the formed laminate as required or during other handling. Hateful.

As a result of the above, a high-quality laminated fired body which can be fired without causing voids or swelling, has excellent adhesion between layers, has no disconnection in the conductor pattern, and has no gaps in the vicinity to form a water immersion path, etc. Can be manufactured well. Further, it is possible to easily automate from the perforation process to the formation of the fired body, which is excellent in manufacturing efficiency.

[0010]

In the present invention, as shown in FIG. 1, in the present invention, the ceramic powder fired during firing of the ceramic green sheet is formed into a sheet form with a heat-sensitive fluidizing agent and a polymer binder on the base film 1 as necessary. A step compensation sheet 2 having a shape is used.

As the ceramic powder, an appropriate powder may be used depending on the firing conditions of the ceramic green sheet to be fired. It is preferable to use a ceramic green sheet having the same composition as the firing target ceramic green sheet from the viewpoint of bonding property. Generally, powders of alumina, zirconia, aluminum nitride, titania, beryllia, barium titanate, magnesium titanate, mullite, steatite, and the like, and other ceramic powders for low-temperature firing are used.

The average particle size of the ceramic powder used is 0.0
1 to 10 μm is suitable, and the amount used is suitable to provide a step compensation sheet having a composition of 20 to 95% by weight. If the content is less than 20% by weight, a sufficient bonding force is not exhibited, the shrinkage during firing is large and a gap is likely to be formed in the vicinity of the conductor powder pattern, and if it exceeds 95% by weight, it becomes difficult to handle as a sheet.

The heat-sensitive fluidizing agent is a binder for imparting easy fluidity to the step compensation sheet by pressing, and an appropriate fluidity material can be used according to the heating temperature when laminating the ceramic green sheets. In general, carboxylic acid waxes such as stearic acid and lauric acid, paraffin waxes such as octadecane and tetracosane, ester waxes such as myristyl myristate and stearyl stearate, higher alcohol waxes, polyethylene waxes, dodecylamine and tetra waxes. Waxes such as amine waxes such as decylamine and euleramine are preferably used.

The amount of the heat-sensitive fluidizing agent used is 5 to 5% of the total binder.
70% by weight, especially 20 to 50% by weight is suitable. If the amount used is less than 5% by weight, the step due to the conductor powder pattern may not be compensated for when laminating the ceramic green sheets, and if it exceeds 70% by weight, it becomes difficult to form the sheet, and the ceramic green sheets are likely to protrude when laminating. ..

As the polymer binder, a polymer having a glass transition temperature of 100 ° C. or lower, especially -5 to 20 ° C., for example, a hydrocarbon polymer, a vinyl or styrene polymer, an acetal polymer, a (meth) acrylic polymer, Olefin-based polymers, ester-based polymers, urethane-based polymers and the like are preferably used. A polymer binder having a glass transition temperature of higher than 100 ° C. may not be able to compensate the step due to the conductor powder pattern when laminating the ceramic green sheets. The amount of the polymer binder used is 5 to 5 based on the total binder including the heat-sensitive fluidizing agent.
A suitable amount is a step compensation sheet having a contained composition of 80% by weight.

The step compensation sheet is formed, for example, by mixing one or more of ceramic powder, a heat-sensitive fluidizing agent, and a polymer binder by using a solvent as necessary, and mixing the mixture with a roll coater, a doctor blade, or the like. It can be carried out by spreading on a base material film or other film or sheet such as a separator with an appropriate coating machine. The method using the base film is preferable because the step of separately adhering to the base film can be omitted. Further, the step compensation sheet can be subjected to perforation treatment by a punching method or the like in the form of being reinforced with a base material film, and the processing treatment and handling thereof are easy, which is preferable. When different kinds of ceramic green sheets are laminated, a step difference compensating sheet composed of a combination system of them or a laminated body of layers individually contained may be used.

When forming the step compensation sheet, additives such as a firing aid and a pigment can be appropriately selected and used depending on the type of ceramic powder. By the way, when alumina is used as the ceramic powder, talc, kaolin, calcium oxide, magnesium oxide, silicon oxide, chromium oxide, molybdenum oxide, titanium oxide,
Zirconium oxide, iron oxide, cobalt oxide and the like are generally used.

The thickness of the step compensation sheet is appropriately determined depending on the thickness of the conductor powder pattern to be compensated. Generally, the thickness is 5 to 200 μm, especially 30 to 120 μm.
If the thickness is too thin, peeling or misalignment easily occurs between the ceramic green sheets during punching, and if it is too thick, the ceramic green sheets are likely to protrude into the holes when laminated, and voids are formed at the bonding interface. Swelling is likely to occur and the interlayer adhesion is likely to deteriorate.

A step compensation sheet which is preferable from the standpoint of preventing protrusion to the hole portion is preferably 5 × 10 ⁷ poise or less, especially 1 under the press temperature condition at the time of laminating the ceramic green sheets.
Melt viscosity of × 10 ⁴ to 1 × 10 ⁶ poise (die diameter 2 mm,
Measured with a flow tester having a length of 10 mm under the condition of a weight of 50 kg / cm ² . The same shall apply hereinafter). If the melt viscosity is too high, the adhesiveness and step compensation will be poor, and if it is too low, protrusion and deformation of the sheet form will be likely to occur.
The melt viscosity can be controlled, for example, by adjusting the use ratio of the polymer binder and the heat-sensitive fluidizing agent according to the press conditions and the like.

In the present invention, as illustrated in FIG. 1, the step compensation sheet 2 and the ceramic green sheet 3 are preliminarily perforated, and the perforated portions 21 and 31 are made to correspond to each other to form a step on the base film 1. The ceramic green sheet 3 is laminated via the compensation sheet 2.

The punching process may be performed by an appropriate method such as a punching method. When the step compensation sheet is used in a state of being laminated with the base film in advance, the step of compensating the step compensation sheet may be performed integrally with the base film. In that case, the processing direction may be from the step compensation sheet side or the base film side, but from the viewpoint of processability, particularly punchability, processing from the base film side is preferable.

The perforations formed are smaller in the perforations 31 provided in the ceramic green sheet 3 than in the perforations 21 provided in the step compensation sheet 2. As a result, the difference between the edge of the perforated portion 21 and the edge of the perforated portion 21, which is formed when the step compensation sheet 2 and the ceramic green sheet 3 are laminated in correspondence with the perforated portions 21 and 31, as a receding portion is the ceramic green. When the sheets are stacked, the step compensation sheet functions as a margin for preventing the forming material from protruding into the holes.

The size of the protrusion prevention margin is appropriately determined according to the increase rate of the area of the step compensation sheet due to the pressing conditions when the ceramic green sheets are laminated. Generally less than 1mm, especially 0.05-0.5
mm perforation (2)
1, 31).

The lamination process of the ceramic green sheet on the substrate film via the step compensation sheet can be carried out by, for example, a method in which the step compensation sheet and the ceramic green sheet are pressure-bonded. Crimping force is 5 to 150
kg / cm ^2, it is appropriate especially 10 to 50 kg / cm ^2. In the pressure-bonding treatment, when a step compensation sheet to which the base film is not adhered is used, the base film, the step compensation sheet, and the ceramic green sheet may be sequentially arranged during the pressure-bonding treatment to perform the adhesion treatment.

The pressure bonding temperature is the glass transition temperature of the polymer binder in the step compensation sheet, the melting point of the heat-sensitive fluidizing agent,
Or, it may be appropriately determined according to the content ratio and the like.
Generally, it is in the range of room temperature to 100 ° C. The adhesive force between the step compensation sheet and the base film is 5 to 250 g / 25 m based on the 180 degree peel value (peel rate 300 mm / min).
m, preferably 10 to 100 g / 25 mm.

If the adhesive force between the step compensation sheet and the base film is too small, a floating occurs between the step compensation sheet and the base film during the perforation process, making it difficult to cut the base film and the cut film. Even if it does, burrs are likely to occur on the cut surface of the substrate film. Further, when the ceramic green sheets are also laminated and subjected to a small perforation process such as through holes, warpage or breakage is likely to occur. On the other hand, when the adhesive force between the step compensation sheet and the base film is excessive, it becomes difficult to peel and remove the base film without damaging the step compensation sheet.

Achieving the above-mentioned adhesive force between the step compensation sheet and the base film can be exemplified by a method of roughening the surface of the base film. If the base film treated with the release agent or the unprocessed base film is left as it is, the heat-sensitive fluidizing agent in the step compensation sheet may hinder the development of the adhesive force and the desired adhesive force may not be exhibited. The surface roughening treatment of the base material film is performed appropriately by, for example, a mechanical treatment method such as a corona treatment method, a plasma treatment method, a sputtering treatment method, or a matte treatment method, or an optical treatment (porosification) such as laser light. You may go by the method.

The substrate film is preferably, for example, a film made of plastic such as polyester, polyethylene, polypropylene or polymethylpentene, or a film in which an inorganic pigment such as carbon, titania or silica, or bubbles are mixed in the plastic. Used. The thickness of the base film is 6 to 150 μm, especially 2
It is preferably 5 to 50 μm. If the thickness is too thin, the workability becomes poor, and if it is too thick, the ceramic green sheet may be deformed during the necessary processing.

If necessary, the ceramic green sheet laminated with the step compensation sheet is subjected to a small perforation process such as through holes, or a conductor powder pattern is formed. In forming the conductor powder pattern, the base film may be removed from the step compensation sheet in advance, or may be removed after forming the conductor powder pattern.

The conductor powder pattern is provided for the purpose of forming a circuit pattern or the like. The pattern is formed by, for example, a method of preparing a mixed paste of a conductor powder and a binder using an organic solvent in a ratio of 5 to 20% by weight, and applying the pattern onto a ceramic green sheet by a screen printing method or the like. It can be carried out.
The layer thickness of the conductor powder pattern is generally 5 to 100 μm, but is not limited to this.

As the conductor powder, it is possible to use a powder made of an appropriate conductor such as a metal such as molybdenum, tungsten, gold, silver, copper, platinum or palladium, or an alloy thereof. The average particle diameter of the conductor powder is generally 0.5 to 10 μm, but is not limited to this.

As the binder, one that disappears when the ceramic green sheet is fired is used. Generally, various polymers including rubber-based polymers are used. Examples thereof include ethyl cellulose, nitrocellulose, alkyl ester-based polymers of acrylic acid and methacrylic acid, polyvinyl butyral-based polymers and the like. As the organic solvent, those capable of dissolving the binder are used, and generally xylene, toluene, ethanol, butanol and the like are used.

As shown in FIG. 2, the ceramic green sheet 3 having the conductor powder pattern 4 and the through holes 5 formed as necessary has the conductor powder pattern 4 formed through the step compensation sheet 2 laminated thereon. If necessary, the ceramic green sheet 3 and the conductor powder pattern surface are laminated and pressure-bonded. At that time, the base film (1) adhered to the step compensation sheet (2) is removed in advance. It should be noted that the ceramic green sheets can be easily aligned and corrected before they are laminated and pressure-bonded.

The lamination pressure bonding process is, for example, 5 to 150 kg / cm.
² , especially by pressing with a pressing force of ^{20 to} 100 kg / cm ² . If the pressing force is too small, the step compensation sheet will not be sufficiently filled in the step portion of the conductor powder pattern, and a gap will easily occur, and if it is too large, it will cause deformation problems of the ceramic green sheet and disconnection problems of the conductor powder pattern. .. The pressure bonding temperature can be the same as in the case of laminating the step compensation sheet and the base film described above.

The combination of the ceramic green sheets to be laminated is arbitrary in both type and number of layers, and may be appropriately determined depending on the intended use of the laminated fired body and the like. As the ceramic green sheet, an appropriate one may be used, such as a sheet obtained by molding a mixture of an organic solvent of ceramic powder and a binder by a screen printing method, a doctor blade method, or the like.

The thickness of the ceramic green sheet is usually 0.05 mm or more and about 0.1 to 2 mm, but is not limited to this. As the ceramic powder, those exemplified in the above step compensation sheet are appropriately selected and used according to the intended use of the product. The average particle size of the ceramic powder is generally 0.1 to 30 μm, but is not limited to this.

As the binder and the organic solvent for forming the ceramic green sheet, those exemplified in the above conductor powder pattern are used. If necessary, a filler, a firing aid, or the like may be added to the ceramic green sheet.

The laminated body of the ceramic green sheets with the step compensation sheet interposed therebetween is subjected to other processing, if necessary, and then fired. By the firing process, the organic components such as the heat-sensitive fluidizing agent and the binder in the ceramic green sheet and the step difference compensating sheet are thermally decomposed and disappeared, and the ceramic powder forming the ceramic green sheet and the conductor powder forming the conductor powder pattern are respectively removed. Integrated and integrated,
In addition, based on the ceramic powder in the step compensation sheet, the fired bodies of the ceramic green sheets are interlayer-bonded and integrated to form a laminated fired body of the object.

The firing conditions may be appropriately determined depending on the type and particle size of the ceramic powder or conductor powder. In general,
It is fired at a temperature of 800 to 2000 ° C. The firing atmosphere may also be determined according to the ceramic powder, conductor powder, or the like.
For example, in the case of a combination of alumina powder and platinum powder, an oxidizing atmosphere is suitable, and in the case of a combination of alumina powder and molybdenum powder, in a vacuum or hydrogen gas atmosphere, hydrogen / nitrogen mixed gas atmosphere, hydrogen / steam. A non-oxidizing atmosphere such as a mixed gas atmosphere is suitable.

[0040]

【Example】

EXAMPLE 95 parts by weight of an alumina powder having an average particle size of 1.5 μm (parts by weight, hereinafter) on a base film made of a polyester film having a thickness of 25 μm, which was roughened by matte treatment and release-treated with a silicone release agent. Same), 2.5 parts of talc, 2.5 parts of kaolin, 20 alkyl polymethacrylates
Parts, and 5 parts of stearyl stearate having a melting point of 41 ° C. were uniformly mixed with 100 parts of toluene in a ball mill, and the slurry prepared was spread and dried to form a step compensation sheet having a thickness of 50 μm. The melt viscosity at 80 ° C. of the step difference compensating sheet was 5.0 × 10 ⁵ poise, and the adhesive force with the base film (180 degree peel, peeling speed 300 mm / min) was 18.5 g / 25 mm.

On the other hand, alumina powder 9 having an average particle size of 1.5 μm
A mixture of 5 parts, 2.5 parts of talc and 2.5 parts of kaolin was shaped with 10 parts of polyvinyl butyral and 3 parts of a plasticizer to obtain a ceramic green sheet having a thickness of 200 μm.

Next, a punching method is used to form a hole having a size of 5.2 mm square in the laminate of the base film and the step compensation sheet, and a hole having a size of 5.0 mm square in the ceramic green sheet ( Cavities) are formed, and the holes are made to correspond to each other, and 70 ° C, 2
A laminated sheet was obtained by pressure bonding under the condition of kg / cm ² . The protrusion prevention margin formed on the periphery of the hole by the above-mentioned lamination was about 0.1 mm.

Then, a plurality of through holes having a diameter of 200 to 500 μm are formed in the laminated sheet by a punching method, the base film is peeled and removed, and conductor powder is formed on the exposed surface of the ceramic green sheet and the through holes. The paste was pattern-coated by a screen printing method to form a conductor powder pattern having a thickness of 30 μm. The conductor powder paste is a mixture of 100 parts of tungsten powder having an average particle size of 5 μm and 2 parts of nitrocellulose using 10 parts of xylene.

Ten of the above ceramic green sheets having the conductor powder pattern formed thereon were stacked on the step compensation sheet so that the conductor powder pattern side of the other ceramic green sheet was positioned, and the temperature was 80 ° C., 40 kg / cm ² , 1 The laminate was obtained by pressure bonding under the condition of 1 minute.

This laminate has excellent adhesion or adhesion between the ceramic green sheets, and no deformation of the ceramic green sheets or division of the conductor powder pattern was observed.
No gap was observed near the conductor powder pattern. Further, no protrusion of the step compensation sheet was observed in the cavity.

The above laminated body was fired in a hydrogen / nitrogen mixed gas atmosphere at 1600 ° C. for 30 minutes to obtain a laminated fired body having a total thickness of about 2.8 mm. This laminated fired body has very good adhesion and bonding strength between layers, no swelling or voids are observed, no deformation such as warpage, no disconnection of the conductor, and good electrical conductivity. There was no gap in the area.

Comparative Example 1 According to the same manner as in Example 1 except that 5.0 mm square holes having the same size as the ceramic green sheet were formed in the laminate of the substrate film and the step compensation sheet. A laminated body and a laminated fired body were obtained. In this case, the step compensation sheet having a thickness of about 100 μm protruded in the cavity at the stage of the laminated body, and the protrusion was recognized at the stage of the laminated fired body.

Comparative Example 2 In addition to the order of forming holes of 5.0 mm square size (cavity) by a punching method after laminating a laminated body of a base film, a step compensation sheet and a ceramic green sheet, the same procedure as in Example was carried out. A laminated body and a laminated fired body were obtained in the same manner. In this case, the step compensation sheet having a thickness of about 100 μm protruded in the cavity at the stage of the laminated body, and the protrusion was recognized at the stage of the laminated fired body.

[0049]

According to the present invention, when a ceramic green sheet is laminated, a step-compensation sheet forming material can be prevented from protruding into a hole such as a cavity, and a laminated fired body having a hole such as a cavity with excellent dimensional accuracy. Can be stably formed.

Further, since the step compensating sheet is interposed, the ceramic powder can be filled in the step portion based on the conductor powder pattern layer provided on the ceramic green sheet, and the laminated fired body having excellent adhesion can be formed without any inter-layer gap and without deformation or conductor. It can be formed without breaking the powder pattern. Further, based on the sheet method, the ceramic green sheets can be laminated through the adhesive layer that is thin and has excellent thickness uniformity, and the manufacturing process of the laminated fired body can be easily automated.

[Brief description of drawings]

FIG. 1 is an explanatory sectional view showing a state in which a step compensation sheet and a ceramic green sheet are laminated on a base film.

FIG. 2 is a cross-sectional explanatory diagram showing a state in which ceramic green sheets are laminated with a step compensation sheet interposed therebetween.

[Explanation of symbols]

 1: Base film 2: Step compensation sheet 21: Perforated part 3: Ceramic green sheet 31: Perforated part 4: Conductor powder pattern 5: Through hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Tominaga 1-2-1, Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation

Claims (2)

[Claims] 1. A step-compensating sheet formed by holding a ceramic powder fired during firing of a ceramic green sheet with a heat-sensitive fluidizing agent and a polymer binder, and a ceramic green sheet having a perforation smaller than the above. A step of laminating the processed one on the base film with a step compensation sheet in correspondence with the perforated portions, and firing a laminate of a predetermined number of ceramic green sheets via the step compensation sheet to integrate them. A method for producing a laminated fired body, comprising the step of: 2. The manufacturing method according to claim 1, further comprising a step of laminating and pressing a ceramic green sheet having a conductor powder pattern formed thereon with a step compensation sheet from which the base film has been removed via the conductor powder pattern surface.