JP2003017351A - Method of manufacturing transfer conductor and method of manufacturing green sheet laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a transfer conductor having a fine pattern and a thick film, and to provide a method for manufacturing a green sheet laminate using the method. SOLUTION: The method includes a process for forming a mask layer having the pattern regulating an exposure part on the surface of a base plate on the base plate having conductivity, a process for forming the transfer conductor on the exposure part of the base plate by electroforming by using plating liquid which does not substantially deforms the mask layer, and a process for transferring the transfer conductor on a body to be transferred without peeling the mask layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a transfer conductor and a method of manufacturing a green sheet laminated body for forming a chip type electronic component such as a laminated chip inductor.

[0002]

2. Description of the Related Art In recent years, miniaturization and thinning of electronic components has been tremendous. For example, multilayer chip inductors are required to be smaller and have higher inductance (high impedance). It is necessary to form a fine pattern of the coiled wound conductor.

In particular, in a multilayer chip capacitor, it is required to realize a smaller size and a larger capacity by forming thinner and more dense internal electrodes.

Further, as high-performance small-sized devices such as mobile phones are put into practical use, it is required to make an LCR module having various functions in one chip into a chip.
In order to realize these, the most important issue is how to form a fine pattern efficiently and precisely.

In the case of manufacturing such a chip type electronic component, the conventional printing technique is widely and generally used, and it is still being researched day and night in order to form a finer conductor pattern. As the current situation, various approaches have been taken such as introducing offset printing technique, increasing the aperture ratio of the screen for screen printing, finely pulverizing the conductor powder of the conductor paste, and improving the vehicle, but industrially. In practice, it is only possible to form a pattern having a conductor line width of about 50 to 80 μm at the most, and the thickness of the conductor of these patterns tends to become thinner as the conductor line width becomes narrower. However, there is a drawback that the conductor resistance value becomes large.

In order to solve such conventional drawbacks, a pattern forming method using a transfer technique is disclosed in Japanese Patent Laid-Open No. 4-3148.
No. 76 publication.

A desired metal layer is obtained by wet plating on a metal thin film having releasability formed by vapor deposition on a film, and if necessary, an extra metal layer is removed by an etching method to form a pattern. Is transferred to the transfer target.

According to this transfer technique, it is possible to form a relatively thin (for example, 10 μm or less) transfer metal film for use as an internal electrode of a laminated ceramic capacitor or the like.

[0009]

However, with the above transfer technique, it is difficult to obtain a relatively thick (for example, 10 μm or more) transfer metal film with fine line pattern accuracy.

That is, in the above transfer technique,
This is because an excessive metal portion is removed by etching the metal layer formed on almost the entire surface, and the thicker the metal layer, the more difficult the fine pattern formation becomes.

Further, since the desired metal pattern remains under the etching resist layer, it is necessary to remove the etching resist before transferring the metal pattern to the transfer object, but the etching resist is peeled off. At this time, the metal pattern may peel off together with the resist. Such a phenomenon is more likely to occur as the thickness of the transferred metal layer increases. It is considered that this is because the thicker the metal layer, the longer the time required for etching, and the metal thin film layer having releasability formed by vapor deposition is attacked by the etchant. .

Furthermore, the transfer method described above is not very efficient because it is necessary to coat a resist for pattern formation every time to form a resist pattern.

The present invention has been made in view of the above problems, and an object thereof is a method of manufacturing a transfer conductor having a fine pattern and a large film thickness, and a method of manufacturing a green sheet laminate using the same. To provide.

[0014]

A method of manufacturing a transfer conductor according to the present invention comprises a step of forming a mask layer having a pattern defining an exposed portion of the surface of the base plate on a conductive base plate, A step of forming a transfer conductor on the exposed portion of the base plate by an electroforming method using a plating liquid that does not substantially deform the mask layer; and the transfer conductor without peeling the mask layer. Is transferred to an object to be transferred, whereby the above object is achieved. The phrase “the mask layer is not substantially deformed” means that the pattern is not substantially deformed by the material of the mask layer being dissolved or swollen by the plating solution. That is, it means that the material of the mask layer has sufficient resistance to the plating solution.

The method of manufacturing a green sheet laminate according to the present invention comprises the steps of forming a mask layer having a pattern defining an exposed portion of the surface of the base plate on a conductive base plate, and a step of forming the base plate. Forming a transfer conductor on the exposed portion by an electroforming method using a plating liquid that does not substantially deform the mask layer; and transferring the transfer conductor without peeling off the mask layer. The step of forming a transfer conductor on the first insulator green sheet, and the step of providing a second insulator green sheet on the surface of the first insulator green sheet having the transfer conductor, The above object is achieved by the above.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

(Embodiment 1) Embodiment 1 of the present invention will be described below with reference to the drawings. In the drawings used in the following description, for simplification, one stacked body for forming one inductor is illustrated. However,
In actual manufacturing, it is possible to form a plurality of inductors by forming a plurality of laminated bodies on one base plate and separating them after the laminated bodies are completed.

FIG. 1 is a sectional view showing a structure of a base metal plate and a mask layer for forming a transfer conductor according to the first embodiment of the present invention.

In FIG. 1, 1 is a base stainless steel plate as a conductive base plate, 2 is a conductive release layer made of a strike Ag plating layer, 3 is a mask layer, and 4 is Ag formed by an electroforming method. The transfer conductors 5 are release layers for imparting releasability to the mask layer 3 formed on the mask layer 3.

A method of manufacturing the transfer conductor 4 using the electroformed conductor transfer mold composed of the base stainless steel plate 1 and the mask layer 3 as described above will be described below.

First, as shown in FIG. 1, an acrylic dry film having acid resistance and alkali resistance was laminated as a mask layer 3 on the entire surface of the base stainless steel plate 1. After lamination, it is dried and cured at about 160 ° C. for 60 minutes, and then dried with an acrylic dry film (for example, Dialon FRA-06
3, manufactured by Mitsubishi Rayon) was adhered to the base stainless steel plate 1.

The thickness of the mask layer 3 thus obtained was about 45 μm after curing. Next, on the surface of the mask layer 3, a liquid fluorine-based coupling agent (perfluorodecyltriethoxysilane) for imparting releasability is released.
As dip coating and curing at 200 ° C. After curing, the film thickness of the release layer 5 is 0.1 μm or less. The release layer 5 does not necessarily have to be formed.

The excimer laser (wavelength: 308 nm) is irradiated (output 50 to 80 W) from above the mask layer 3 and the release layer 5 thus formed to a portion where a conductor pattern is to be formed, and the base stainless steel plate 1 is exposed. Patterning (corresponding to 7 or 10 in FIG. 2) is performed so that the desired conductor pattern having a width of 40 μm is exposed in the form of a wound coil to obtain a resist pattern.

By the irradiation of such excimer laser,
Since the mask layer 3 is removed cleanly and patterned, a fine pattern with high resolution can be obtained, unlike the usual laser processing for cutting by heat load such as YAG laser. Further, in the wavelength region of the excimer laser, there is no concern that the base stainless steel plate 1 will be damaged.

The mechanism of resin cutting by such an excimer laser is considered to be because the energy of wavelengths of 308 nm and 248 nm of the excimer laser has a chemical reaction action of cutting the molecular chain of acrylic resin. . For example, the carbonyl group of the acrylic resin is cleaved by irradiation with excimer laser light.

Since the mask layer 3 formed as described above is firmly adhered to the base stainless steel plate 1, it is not peeled off. Therefore, it is transferred again to the base stainless steel plate 1 on which the mask layer 3 remains by electroforming. By forming the use conductor 4, the mask layer 3 can be reused.

If the transfer conductor 4 is sandwiched between the mask layers 3 and it is difficult to transfer the pattern, the transfer conductor 4 can be pulled out by using various adhesive sheets.

By determining the laser output condition according to the minimum width of the pattern and the thickness of the resist, the minimum line width 10
It is also possible to obtain a pattern having a thickness of about 50 μm with a thickness of about μm.

Using a photosensitive acrylic dry film,
When patterning the mask layer by photolithography, it is easy to form a thin pattern having a pattern width of about 10 to 30 μm, but it is difficult to increase the thickness of the resist (when the pattern width is 10 μm, the resist thickness is at most). The limit is about 10 μm.).

Then, the exposed metal portion is subjected to strike Ag plating as the conductive release layer 2 to obtain the Ag release layer 2 having a thickness of 0.1 μm or less.

Strike Ag plating can be carried out by using a general alkaline cyan-based Ag plating bath. As an example, a plating bath as shown in (Table 1) is illustrated.

[0032]

[Table 1]

In the case of the Ag plating bath of (Table 1), 5 to 2
The conductive release layer 2 having a thickness of about 0.1 μm can be obtained in about 0 seconds.

By the way, the conductive release layer 2 has releasability because, in general, the adhesion between the base stainless steel plate 1 and Ag is poor, and the Ag film is strike (high speed) plated. There are many strains in the film, and
It is considered that this is because the g film cannot firmly adhere to the base stainless steel plate 1.

The conductive release layer 2 can also be formed by utilizing the silver mirror reaction. Further, as the base metal plate, a material other than stainless steel may be used to impart releasability. The main usable materials and their release treatment methods are listed in (Table 2).

[0036]

[Table 2]

It is also possible to impart the same effect by imparting conductivity to a PET film or the like in addition to the base metal plate, but it is not necessary to impart conductivity to the metal plate, so that it is practical. It is efficient.

In particular, the stainless steel plate is chemically stable and has a chromium-based oxide film on the surface thereof, so that it has releasability by itself and is most practical.

Next, the step of forming the transfer conductor 4 by electroforming will be described. First, the transfer conductor 4 having a required thickness t is formed by immersing it in an Ag electroplating bath. In this embodiment, t
= 40 to 45 μm.

In order to form a transfer conductor having a shape and size corresponding to the pattern of the mask layer, the transfer conductor 4 is used.
Is optimally within a range not exceeding the thickness of the mask layer 3 and thinner than the thickness of the mask layer 3 by about 5 μm.
This is because if the transfer conductor 4 is thicker than the mask layer 3 when the transfer conductor 4 is formed by plating, the transfer conductor 4 wraps around in the lateral direction and grows. This is because the resolution of the pattern can not be fully utilized. On the other hand, if the thickness of the mask layer 3 is thinner than the thickness of the mask layer 3 by 5 μm or more, the transfer conductor 4 to be described later may not be satisfactorily transferred to the green sheet.

On the other hand, when the resolution is not important, FIG.
As shown in, the conductor 4 thicker than the thickness of the mask layer 3 may be formed. The portion protruding from the mask layer 3 bites into the green sheet in the transfer process, so that the transferability is improved. Further, since the cross-sectional area of the transfer conductor 4 is enlarged, there is also an effect of reducing the resistance of the transfer conductor 4. However, since the transfer conductor 4 is isotropically formed on the upper portion of the mask layer 3, it is necessary to make adjustment so that a short circuit does not occur between the adjacent conductors 4.

Since the mask layer in the present embodiment has both acid resistance and alkali resistance, basically any plating bath composition can be used to form the transfer conductor 4. Depending on the type of the mask layer, it functions as a stripping solution for the mask layer, so that the mask layer patterned in the previous step may be destroyed, and it is necessary to selectively use it.

Particularly, from the viewpoint of prolonging the service life of the mask layer, in this embodiment, it is weakly alkaline (neutral).
Of Ag plating bath was used.

As the weakly alkaline (neutral) plating bath, those shown in (Table 3) can be used.

[0045]

[Table 3]

However, the current density was set to about 1 A / dm ² . This is because, since plating is performed at high speed, when the current density is increased, the distortion of the transfer conductor 4 is increased, and the transfer conductor 4 may be separated before the pattern is transferred.

Therefore, in this example, about 160 minutes of plating time was required to obtain the transfer conductor 4 having a thickness of about 40 μm.

In the case of mass-producing a large number of patterns at the same time, such a time of 160 minutes is a very short time.

The conductive release layer 2 was formed by a strike Ag plating bath (alkaline), but a weak alkaline (neutral) plating bath for forming the transfer conductor 4 as described above. It is also possible to impart releasability to the Ag film near the interface with the base stainless steel plate 1 by increasing the current density and increasing the strain of the Ag film only in the first few minutes.

In this case, it is not necessary to purposely provide the conductive release layer 2. As the acidic Ag plating bath for forming the transfer conductor 4, those shown in (Table 4) can also be used.

[0051]

[Table 4]

Since the Ag plating bath was acidic, peeling of the plating resist was not observed. Furthermore, Ag gloss could be increased by adding a surfactant (methylimidazole thiol, furfural, funnel oil, etc.).

As an example, the transfer conductor 4 formed as described above was transferred to a magnetic green sheet to make a multilayer chip inductor.

FIG. 2 is an exploded perspective view of the multilayer chip inductor prototyped in this embodiment. First, a method of forming the magnetic green sheets 6, 8 and 11 will be described.

A vehicle in which a resin such as butyral, acryl or ethyl cellulose is dissolved by adding a solvent having a high boiling point such as terpineol and a plasticizer such as dibutyl phthalate if necessary, and a Ni / Zn / Cu ferrite powder (average particle size 0 0.5 to 2.0 μm) is mixed to form a paste (slurry) ferrite on a PET film by the Dota Cool blade method, and dried at about 80 to 100 ° C. until a little stickiness is left. The magnetic green sheets 6, 8 and 11 are obtained.

The magnetic material green sheet layers 6 and 11 are formed so as to have a thickness of about 0.3 to 0.4 mm, and the magnetic material green sheet layer 8 is formed to have a thickness of about 20 to 100 μm and then punched or the like. Depending on 0.15-0.3m
The through hole 9 of about m is penetrated.

Next, the transfer process will be described. First, the magnetic green sheet layer 6 formed on the PET film
Then, the wound coil-shaped transfer conductor 7 (corresponding to 4 in FIG. 1) that has already been formed is pressed and transferred (pressurization or heating may be performed if necessary).

At this time, the wound coil-shaped transfer conductor 7 has a good releasability from the base stainless steel plate 1, and the magnetic green sheet layer 6 has a good adhesive property. By peeling the magnetic green sheet 6 from, the wound coil-shaped transfer conductor pattern 7 is easily transferred to the magnetic green sheet layer 6.

If the mechanical strength of the magnetic green sheet 6 is not sufficient, an adhesive sheet may be provided on the magnetic green sheet.

Since the surface of the acrylic mask layer 3 is coated with the release layer 5, the magnetic green sheet 6 is easily separated from the mask layer 3 and the release layer 5.

Next, the wound coil-shaped transfer conductor 10 is transferred to the magnetic green sheet layer 11 by the same process.

Further, the magnetic green sheet 6, onto which the two wound coil-shaped transfer conductors 7 and 10 thus obtained are transferred,
The magnetic green sheet layer 8 is arranged between the two 11, and the two winding coil-shaped transfer conductors 7 and 10 are connected to each other through the through holes 9 and heated (60 to 120 degrees).
Heating (20 to 500 kg / cm ² ) completes the connection between layers.

However, in many cases, a more ohmic connection can be obtained by electrically connecting the two wound coil-shaped transfer conductors 7 and 10 through a thick film conductor. The printed thick film conductor 21 is printed and filled in the through hole 9 of the sheet layer 8 in advance.

In the above process, a plurality of conductor patterns are generally formed on one sheet in order to obtain a plurality of multilayer ceramic chip inductors at the same time in order to improve manufacturing efficiency. Therefore, after cutting into individual multilayer chip inductors, 850-100
Baking is performed at 0 ° C. for about 1 to 2 hours. The cutting can also be performed after firing.

Finally, a silver alloy-based take-out electrode is formed on the opposing outer piece of the chip so as to be connected to the internal coiled transfer conductor, and is baked at about 600 to 850 ° C. The external electrode 12 shown in FIG. 3 is formed. If necessary, the outer electrode 12 is plated with Ni, solder, or the like.

With this process, the outer shape 1.6 ×
A multilayer ceramic chip inductor having a thickness of 0.8 mm and a thickness of 0.8 mm was obtained. The internal conductor has a two-layer structure of about 2.5 turns of Ag conductor and has a total of 5 turns of a coiled conductor line, so that an impedance of 100 MHz can be about 600Ω.

DC resistance is about 40 μm for Ag conductor thickness.
Therefore, it was extremely small and could be about 0.08Ω.

When the multilayer ceramic chip inductor according to the present embodiment was cut and observed, no particular gap was observed at the interface between the Ag conductor and the magnetic layer.

This is because the wound coil-shaped transfer conductor formed by the electroforming method of the present embodiment has almost no shrinkage due to firing unlike the film thickness conductor which requires the binder removal, and therefore, the Ag conductor of It is considered that the magnetic material was densely sintered around it.

Although an acrylic dry film is used as the mask layer in the present embodiment, other examples of the mask layer having excellent acid resistance and alkali resistance include fluorine, acrylic, epoxy, polyethylene, polyacetal and the like. In order to strengthen the resin and its modified products, rubbers, and further the hardness of the mask layer, it is possible to use those in which various ceramic powders are dispersed as fillers in the resin film.

Further, as a method of depositing these resins,
Various applications such as spray coating, roll coating, dip coating, electrostatic coating, printing, dry film lamination, and film-like resin adhesion can be used.

Further, an electrodeposited or sprayed film of an inorganic material such as ceramic, glass or metal can be used.

As for patterning the mask layer,
In addition to the excimer laser irradiation shown in the present embodiment, it is also possible to use development by light exposure, laser processing with YAG or CO ₂ , and physical cutting such as sandblasting, water jet, and cutting.

Further, in the present embodiment, electroplating is used because it is the most desirable from the viewpoint of film deposition rate, but electroless plating is technically possible.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a sectional view showing a structure of a base metal plate and a mask layer for forming a transfer conductor according to the second embodiment of the present invention.

In FIG. 4, 13 is a base stainless steel plate,
Reference numeral 14 is a mask layer, and 15 is a transfer conductor formed by electroforming.

A method of manufacturing the transfer conductor 15 having the above structure will be described below. As shown in FIG. 4, after the base stainless steel plate 13 is degreased and washed, a mask pattern having a pattern opposite to the pattern of the mask layer 3 of the first embodiment (formed by an electroforming method formed just after) is formed on the base stainless steel plate 13. (Corresponding to the pattern of the transfer conductor 15), and then a mask layer 1 made of a fluorine resin (Polyflon TC-7400 manufactured by Daikin Industries, Ltd.) having acid resistance and alkali resistance over the entire surface.
4 coated. After preliminary drying and curing at about 200 ° C. for 3 to 5 minutes, the photoresist pattern is peeled off to form a fluorine resin layer pattern, and then about 280
After the main curing at 3 ° C. for 3 to 5 minutes, the base stainless steel plate 13 was firmly bonded.

By this step, the portion where the mask layer 14 is not formed is patterned so that the base stainless steel plate 13 is exposed.

The thickness of the mask layer 14 is about 45 μm after curing.
Met. Since the fluorine resin has a good releasability, it is not necessary to particularly form the release layer 5 as shown in FIG. 1 of the first embodiment.

In the first embodiment, the conductive release layer 2 is formed on the base of the transfer conductor 4 by the strike Ag plating bath (alkaline). However, a fluorine-containing resin having strong alkalinity is used as a resist. In the case of the embodiment,
In an alkaline Ag plating bath as shown in (Table 1), the current density is increased only for the first few minutes to increase the strain of the Ag film, thereby releasing the Ag film near the interface with the base stainless steel plate 13 from the mold. It is also possible to form the transfer conductor 15 by thickening Ag plating after reducing the current density after imparting the property.

That is, in this case, it is not necessary to purposely provide a conductive release layer on the base of the transfer conductor.

After the transfer conductor 15 having a thickness of 43 μm is obtained in this manner, as shown in FIG. 5, a thermal releasable adhesive sheet (foamed sheet, for example, Liver Alpha No. 3194) is used.
M Nitto Denko) 16 is attached, 20 kg / cm ² , 1
The pattern of the transfer conductor 15 could be transferred to the thermal releasable adhesive sheet by applying pressure and heating at 00 ° C. for about 5 to 10 seconds.

Since such a heat-releasing adhesive sheet has high adhesiveness and the thickness of the adhesive layer is large, when the adhesive sheet is pressed, the adhesive layer is deformed to adhere the transfer conductor to the transfer sheet. The conductor is reliably transferred.

Further, as shown in FIG. 6, the transfer conductor 1
The ceramic green sheet 17 previously formed on the PET film 18 is attached to the upper part of the No. 5 under suitable conditions (for example, 10 to 100 kg / cm ² , 60 to 120 ° C., 5
By applying pressure and heating for 10 seconds), the ceramic green sheet 17 is transferred onto the transfer conductor 15.

After that, the heat-releasing adhesive sheet 16 is heated to a high temperature (120 to 150 ° C.) to heat-releasing the adhesive sheet 16.
By foaming the foam layer, the green sheet 17 to which the transfer conductor 15 is transferred can be obtained.

As an application example of the above transfer process, the transfer process described below can also be used.

Up to the state shown in FIG. 4, the transfer conductor 15 is obtained by the same method as described above. Next, as shown in FIG. 7, a ceramic green sheet forming paste is formed on the transfer conductor 15 and the mask layer 14 at an appropriate thickness (for example,
50-100 μm) is screen-printed and dried to obtain a printed ceramic green sheet layer 19.

In the printed ceramic green sheet layer 19 thus formed, the resin component (eg, butyral) which constitutes the printed ceramic green sheet layer 19 is made a little larger than usual in advance, and the sheet strength of the printed ceramic green sheet layer 19 is increased. By making it strong, the printed ceramic green sheet layer 19 and the transfer conductor 15 can be peeled together from the base stainless plate 13 and the mask layer 14.

In some cases, a thermal releasable adhesive sheet 20 (for example, Riva Alpha No. 3194M manufactured by Nitto Denko) is made to adhere (heat or pressure may be applied) from above the printed ceramic green sheet layer 19. After that, the thermal releasable adhesive sheet 20, the printed ceramic green sheet layer 19 and the transfer conductor 15 are integrated, separated from the base stainless steel plate 13 and the mask layer 14, and further heated, whereby the thermal releasable adhesive sheet 20. It is also possible to obtain a ceramic green sheet layer 19 integrated with the transfer conductor 15 as shown in FIG. 8 by foaming and releasing.

In this process, the film thickness of the transfer conductor 15 is considerably larger than that of the mask layer 14 (5 μm or more).
The ceramic green sheet layer 19, which is thin but has adhesiveness, has a feature that the release property of the transfer conductor 15 is improved because the ceramic green sheet layer 19 penetrates to the surface of the transfer conductor 15 when the ceramic green sheet layer 19 is formed by printing. .

(Embodiment 3) In the present embodiment, a method of reflecting the resolution (size and shape) of the pattern formed on the mask layer and forming a transfer conductor thicker than the thickness of the mask layer is described. , Will be described with reference to FIG.

First, the mask layer 3 having a predetermined pattern is formed on the base stainless steel plate 1 by the same method as in the first embodiment.

Next, the exposed portion of the base stainless steel plate 1 is etched using the mask layer 3 as an etching mask. For example, an iron chloride aqueous solution (concentration 30
˜40%) and etching at 40 ° C. for several minutes to form a recess (groove) 22 having a depth of about 20 μm. Since iron chloride does not damage materials other than iron, the material for the mask layer described in the first embodiment can be used as it is as an etching mask.

When the recessed portion (groove) 22 is formed too deep in the exposed portion of the base stainless steel substrate, the width of the recessed portion becomes wider than the width of the exposed portion, so that the transfer conductor 4 formed in the recessed portion cannot be transferred. Therefore, the depth of the recess 22 is about 20.
It is preferable to set the thickness to less than μm.

Next, heat treatment is applied to form an oxide film (not shown) on the surface of the recess 22 formed by etching. This is because the oxide film has an appropriate releasability from the transfer conductor as described above. Further, the release layer 2 may be formed by using strike plating. By forming the oxide film and the release layer 2,
By increasing the releasability of the transfer conductor 4, the yield in the transfer process can be improved. However, the formation of the oxide film or the release layer can be omitted.

Thereafter, similarly to the first embodiment, the transfer conductor 4 is formed on the exposed portion of the base stainless steel plate 1 having the recess 22 by electroforming, and the transfer conductor 4 is transferred to the transfer target.

As shown in FIG. 10, the transfer conductor 4 having a thickness of 50 to 55 μm can be formed by setting the thickness of the mask layer 3 to 40 μm and the etching depth to 15 μm.

(Embodiment 4) In this embodiment, a method of manufacturing a transfer conductor having a thickness larger than that of a mask layer and a method of manufacturing a green sheet laminate will be described.

FIG. 11 is a process drawing showing the method of manufacturing the transfer conductor of the present embodiment. First, a stainless steel base plate 113 is used as a conductive base plate, and the base plate 113 is degreased with an alkaline cleaner or the like, then washed with water and dried (FIG. 11A). In this embodiment, a flexible stainless plate (for example, SUS430) having a thickness of about 0.1 mm is used.

A liquid photoresist is spin-coated on the base plate 113 and dried to give a thickness of 5 μm.
The mask layer 114 is formed (FIG. 11B). In order to utilize the ease of pattern formation of the liquid resist, the thickness of the liquid resist is preferably in the range of 2 to 10 μm. The method for applying the liquid resist is not limited to the spin coating method, and a roll coating method or a screen printing method may be used. As the liquid photoresist, for example, a positive type resist OFPR800 (manufactured by Tokyo Ohka) can be used. On the mask layer 114 made of photoresist,
Parallel ultraviolet rays (UV) are emitted through a photomask 116 formed of chrome or the like (FIG. 11C). afterwards,
After development using an alkali developing solution (for example, sodium carbonate aqueous solution), post-baking is performed at about 150 ° C. for 30 minutes to obtain a mask layer 114 having a predetermined pattern (FIG. 11D). This mask layer 114 can be repeatedly used.

Next, Ag plating is performed. Prior to Ag plating, the exposed portion of the stainless steel plate 113 may be activated if necessary. For example, the activation treatment can be performed by immersing in a 5% sulfuric acid aqueous solution at 40 ° C. for 30 seconds.

Next, Ag is attached to the exposed portion of the stainless steel plate 113.
The release layer 112 is formed by performing strike plating.
It is formed (FIG. 11E). Ag strike plating is
Acid type plating solution that does not contain cyan (for example, die
Silver Bright PL-50: manufactured by Daiwa Kasei Co., Ltd.
Can be done using. Strike silver plated current tight
0.3A / dm²For a few minutes at 0.1
The release layer 112 having a thickness of 1 μm can be formed. Continued
, Thick Ag plating, and transfer conductor of 20-25 μm
The body 115 is formed (FIG. 11F). Thick Ag Me
K is a plating solution containing no cyanide (Dyne Zirva-A
GPL30: manufactured by Daiwa Kasei Co., Ltd.
It was carried out under acidic conditions of 1.0. Liquid temperature 40 ℃, current density 1 ~
2 A / dm ²About 20 minutes Ag of about 50 minutes
The transfer conductor 115 made of a plated film can be formed. Me
The pH of the paste is preferably about 1 to 7, more preferably 1 to 4
preferable. Also, the cyan used in this embodiment is not included.
The plating solution has no toxicity, is safe for work, and is a waste solution treatment.
Reasonable simplicity, improved work efficiency and reduced manufacturing cost
Is possible. At this time, the mask layer 114
The Ag plating film formed on the upper part of the chest is also formed in the lateral direction.
As a result, the line width of the transfer conductor 115 is
Exposure of the stainless steel plate 113 defined by the mask layer 114
Wider than the width of the section. The line width of the transfer conductor 115 is
Almost the same as the height h protruding from the upper surface of the layer 114
Spread laterally. Therefore, the transfer conductor
Pattern of the mask layer 114 at the stage of designing the conductor pattern
It is necessary to set the line width and line spacing of the line. Figure 11
In the example of (f), the height h of Ag plating is 20 μm,
Pattern layer width (width of exposed part) is 20 μm, mask layer
Pattern spacing (spacing between exposed parts) is 60 μm,
The width of the transfer conductor 115 is 60 μm, and between the transfer conductors 115
Is 20 μm.

The transfer conductor 115 thus obtained is transferred to the insulating green sheet as follows. In this embodiment, an insulator green sheet 111 having a thickness of 100 μm manufactured as follows is used. A vehicle in which a resin such as butyral resin, acrylic resin, or ethyl cellulose is dissolved in a low boiling point solvent such as toluene, xylene, or butyl acetate, and a plasticizer such as dibutyl phthalate, and Ni.Zn.
Cu-based ferrite powder (average particle size 0.5-2.0μ
m) is kneaded with slurry ferrite to form on a PET film by a doctor blade method,
It is dried at a temperature of ℃ and an insulator green sheet 111 is obtained. The stainless sheet 113 having the mask layer 114 on which the transfer conductor 115 is formed is attached to the green sheet 111 so that the transfer conductor is in contact with the green sheet. 9
Heating and pressurization are performed under conditions of 0 ° C. for 5 seconds and a pressing pressure of 80 kg / cm ² (FIG. 11 (g)). At this time, the portion of the transfer conductor 115 protruding from the mask layer 114 bites into the green sheet 111.

Next, the stainless steel plate 113 on which the mask layer 114 is formed is peeled off to transfer the conductor 11 for transfer.
5 and the conductive release layer 112 are transferred to the green sheet 111 (FIG. 11 (h)). At this time, the stainless plate 11
Since 3 has flexibility, it deforms as shown in FIG. 11 (h) and can be easily peeled off. After this,
Using the stainless plate 113 having the mask layer 114,
Steps after the step of FIG. 11E can be performed.

In the above example, the transfer conductor is directly transferred to the insulating green sheet, but the transfer conductor may be transferred to the insulating green sheet after the thermal release sheet is transferred.

According to the present embodiment, it is relatively thin (about 2
-10 μm) using a mask layer, sufficient thickness (about 10 μm
m or more) can be formed. Therefore, a photoresist can be used to easily form a mask layer having a high-resolution pattern and a thick film transfer conductor having a sufficiently low resistance. Further, the transfer conductor in the present embodiment projects from the mask layer and cuts into the transfer target such as a green sheet in the transfer step, and thus has excellent transferability.

Next, a method of manufacturing a green sheet laminate having a plurality of conductor layers using the transfer conductor protruding from the mask layer described above will be described with reference to FIGS. 12 (a) to (e). .

A thermal foam sheet 216 is provided on the base stainless steel substrate 220. A magnetic material green sheet having a thickness of 100 μm was prepared in the same manner as the above-mentioned green sheet 111.
The green sheet laminate 211, which is a stack of two sheets, is formed into a thermal foam sheet 2.
It is formed on 16 (FIG. 12A). The green sheet laminated body 211 may be formed by previously laminating four green sheets, or may be formed by laminating four sheets one by one on the thermo-foaming sheet 216. Also,
The thickness of the green sheet laminate can be changed as needed. The thickness of each green sheet may be changed, or the number of laminated green sheets may be changed.

Next, using the stainless steel plate 213 having the conductive release layer 212, the transfer conductor 215, and the mask layer 214 obtained in the steps of FIGS. Similarly to (g) and (h), the conductive release layer 212 and the transfer conductor 215 are transferred to the green sheet laminate 211 (FIG. 12B). In this way, the first conductor layer is obtained.

Next, an intermediate layer for electrically connecting the first conductor layer and the second conductor layer to be laminated later is laminated. The intermediate layer has a through hole 209 in which the magnetic green sheet 208 is filled with Ag paste. Positioned and laminated on the first conductor layer so that electrical contact between the first and second is obtained. For example, 90 ℃,
It can be laminated by applying a pressure of 80 kg / cm ² for about 2 seconds (FIG. 12C).

The above intermediate layer can be formed, for example, by the following method. A through hole having a diameter of 0.15 mm is mechanically formed at a predetermined position of a magnetic green sheet 208 having a thickness of 100 μm obtained in the same manner as in the first embodiment using a puncher or the like. The through hole is filled with Ag paste by using a screen printing method. The material with which the through holes are filled is not limited to Ag paste, and a material having conductivity can be appropriately used. The shape of the through hole is not limited to the circular shape, and may be a rectangular shape or a square shape.

Next, the second conductor layer is laminated on the intermediate layer in the same manner as the first conductor layer. By alternately repeating the lamination of the intermediate layer and the conductor layer, a green sheet laminate having an arbitrary number of conductor layers can be formed (FIG. 12).
(D)).

After forming the required number of conductor layers, the insulator green sheet laminate 206 is laminated on the uppermost layer (FIG. 12).
(E)). Similar to the green sheet laminate 211, the green sheet laminate 206 may be a laminate of a plurality of green sheets in advance, or may be formed by repeating the step of sequentially laminating green sheets on a conductor layer. Good. Moreover, you may pressurize the whole laminated body again (for example, 100-500 kg / cm < ² >, 30 degreeC, 1 minute) as needed.

Thereafter, a ceramic chip inductor can be manufactured in the same manner as in the first embodiment. According to the method for manufacturing a green sheet laminate of the present embodiment, a ceramic chip inductor having a plurality of conductor layers can be easily manufactured. Therefore, it is possible to efficiently manufacture a ceramic inductor having a small resistance and a large inductance.

For example, 4 of (a) to (d) shown in FIG.
By stacking the transfer conductors of one pattern while electrically connecting them through the intermediate layer, a spiral coil conductor of about 9 turns is formed. Also, (a) and (d)
When combined with each other, a spiral coil conductor having about 5 turns is formed. Furthermore, (a) / (b) / (c) /
Approximately 13 if 6 layers of (b) / (c) / (d) are combined
Turn (a) / (b) / (c) / (b) / (c) /
Approximately 17 if 8 layers of (b) / (c) / (d) are combined
A spiral coil conductor of turns is obtained.

The characteristics of the ceramic chip inductor having a size of 1.6 × 0.8 mm obtained by using the method for producing a green sheet laminate of the present invention are shown in (Table 5). As described above, according to the present invention, it is possible to efficiently manufacture a ceramic inductor having a small resistance and a large inductance.

[0118]

[Table 5]

In each of the above embodiments, only Ag was described as the transfer conductor, but Ni, Cu, Pd, Pt, A
Any metal that can be formed by the electroforming method, such as u, Cr or the like, or an alloy thereof, can be used.

As described in each of the above embodiments,
The method for producing a transfer conductor of the present invention, on a conductive base plate, a step of forming a mask layer having a pattern defining an exposed portion of the surface of the base plate, and the exposed portion of the base plate, A step of forming a transfer conductor by an electroforming method using a plating liquid that does not substantially deform the mask layer; and a step of transferring the transfer conductor to a transfer target without peeling the mask layer. The above object is achieved thereby. The phrase “the mask layer is not substantially deformed” means that the pattern is not substantially deformed by the material of the mask layer being dissolved or swollen by the plating solution. That is, it means that the material of the mask layer has sufficient resistance to the plating solution.

Further, before the transferring conductor forming step, a step of forming the exposed portion of the base plate into a concave shape by using an etching method may be further included.

The transfer conductor forming step further includes the step of forming a conductive release layer on the exposed portion of the base plate, and is a step of forming the transfer conductor on the conductive release layer. May be.

The conductive release layer and the transfer conductor may be made of the same material. Further, the mask layer forming step includes a step of forming a photoresist layer on the base plate, a step of exposing and developing the photoresist layer, and even a step of forming the mask layer composed of the photoresist layer Good.

The mask layer forming step includes a step of forming a photoresist layer on the base plate, a step of forming a temporary exposed portion on the surface of the base plate by exposing and developing the photoresist layer, and It may be a step of forming the mask layer made of the insulator layer, which includes a step of forming an insulator layer on the provisionally exposed portion and a step of peeling off the exposed and developed photoresist layer.

Further, the mask layer forming step includes a step of forming an insulator layer on the base plate and a step of irradiating the insulator layer with excimer laser light, and the mask layer made of the insulator layer is formed. It may be a step of forming.

Further, it is preferable that the mask layer has releasability from the transferred material. Further, before the transfer step, a step of forming a layer having releasability with respect to the transfer target on the surface of the mask layer may be further included.

Further, the transfer conductor forming step may be a step of forming the transfer conductor protruding from the mask layer.

In the transfer conductor forming step, a plating solution having a pH in the range of 1 to 7 and containing no cyan may be used as the plating solution.

The method for manufacturing a green sheet laminate of the present invention comprises the steps of forming a mask layer having a pattern defining an exposed portion of the surface of the base plate on a conductive base plate, and the step of forming the base plate. Forming a transfer conductor on the exposed portion by an electroforming method using a plating liquid that does not substantially deform the mask layer; and transferring the transfer conductor without peeling off the mask layer. Thus, the method includes the step of forming a transfer conductor on the first insulator green sheet and the step of providing a second insulator green sheet on the surface of the first insulator green sheet having the transfer conductor. It is a thing.

Further, the transfer conductor forming step may be a step of directly transferring the transfer conductor to the first insulating green sheet without peeling off the mask layer.

In the transfer conductor forming step, the transfer conductor is transferred to the thermal releasable adhesive sheet without peeling off the mask layer, and the transfer conductor to which the thermal releasable adhesive sheet is transferred is transferred. May be transferred to the first insulator green sheet.

In the transfer conductor forming step, a step of applying an insulating paste so as to cover the mask layer on which the transfer conductor is formed and drying it to form a first insulating green sheet, and the mask layer are formed. A step of transferring the transfer conductor to the first insulating green sheet without peeling may be included.

Further, a step of forming a plurality of first insulator green sheets having transfer conductors, and a step of laminating the plurality of first insulator green sheets while electrically connecting the plurality of transfer conductors to each other. And may be further included.

Further, the method may further include the step of sandwiching the third insulator green sheet having the through holes between the plurality of first insulator green sheets.

Further, the method may further include a step of sandwiching a third insulator green sheet having a through hole filled with the printed thick film conductor between the plurality of first insulator green sheets.

Further, the method may further include a step of sandwiching a third insulator green sheet having a through hole filled with a conductor formed by electroforming between a plurality of first insulator green sheets. Good.

Also, the step of forming the first transfer conductor by directly transferring the transfer conductor to the first insulating green sheet without peeling off the mask layer, and the step of forming the first transfer conductor. 1 step of laminating a third insulator green sheet having a through hole on the surface of the insulator green sheet, and directly transferring the transfer conductor to the third insulator green sheet without peeling off the mask layer Accordingly, the method may include a step of forming a second transfer conductor and a step of laminating a second insulator green sheet on the surface of the third insulator green sheet having the second transfer conductor.

The first and second insulating green sheets may be made of magnetic material.

[0139]

As described above, according to the present invention, a fine pattern conductor can be transferred onto a ceramic green sheet even if the transfer conductor is thick.

According to the present invention, the transfer conductor is formed on the exposed surface of the base plate defined by the mask layer formed on the conductive base plate. That is, the transfer conductor is formed in the concave portion of the mask layer having sufficient adhesive strength with the base plate. Although the adhesive force between the transfer conductor and the base plate or the release layer formed on the base plate is weak, the transfer conductor is sufficiently held by the frictional force at the interface between the mask layer and the transfer conductor. Therefore, the line width is narrow (for example, about 30 to 6).
(0 μm) Even when the transfer conductor is formed by electroplating, the transfer conductor is not separated from the base plate due to the flow of the plating solution in the plating process, the water flow in the cleaning process, or the like. Further, as in the fourth embodiment,
With respect to the transfer conductor protruding from the mask layer, the convex portion of the transfer conductor bites into the transfer target, so that transferability can be improved.

By applying such a transfer technique to a laminated ceramic chip inductor or the like, a conductor having a fine pattern and a large conductor film thickness (a small conductor resistance value) is obtained, and a laminated body having a large inductance (impedance). Type ceramic chip inductors can be obtained with a low number of laminated layers.

The conductor film thickness can be submicron to several tens of microns depending on the resist film thickness and plating conditions, or can be several millimeters depending on the conditions.

On the other hand, unlike the case of the thick film conductor which requires the removal of the binder, the conductor of the present invention produced by the plating method has a small shrinkage of the conductor thickness after firing, so that delamination of the magnetic layer and the conductor layer occurs. There is nothing.

Further, since the pattern forming mask layer is not released from the mold and only the transfer conductor itself is transferred, the resist pattern can be reused many times.

[Brief description of drawings]

FIG. 1 is an explanatory sectional view showing a method for forming a transfer conductor according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the structure of the multilayer ceramic chip inductor according to the first embodiment.

FIG. 3 is a perspective view of the multilayer ceramic chip inductor according to the first embodiment.

FIG. 4 is an explanatory sectional view showing a method for forming a transfer conductor according to a second embodiment of the present invention.

FIG. 5 is an explanatory sectional view showing a method for forming a multilayer ceramic chip inductor according to the second embodiment.

FIG. 6 is an explanatory sectional view showing a method for forming a multilayer ceramic chip inductor according to the second embodiment.

FIG. 7 is an explanatory sectional view showing a method for forming a multilayer ceramic chip inductor according to the second embodiment.

FIG. 8 is an explanatory sectional view showing a method for forming a multilayer ceramic chip inductor according to the second embodiment.

FIG. 9 is an explanatory sectional view showing a method for forming another multilayer ceramic chip inductor according to the second embodiment.

FIG. 10 is an explanatory sectional view showing a method for forming a transfer conductor according to a third embodiment of the present invention.

FIG. 11 is a sectional view showing a method for manufacturing a transfer conductor and a green sheet laminate according to a fourth embodiment of the present invention.

FIG. 12 is a sectional view showing a method for manufacturing a green sheet laminate according to a fourth embodiment of the present invention.

FIG. 13 is a view showing a pattern of a transfer conductor used in the present invention.

[Explanation of symbols]

1,13 base stainless steel plate 2 Conductive release layer 3,14 Mask layer 4,15 Transfer conductor 5 Release layer 6,8,11 Magnetic green sheet 9 through holes 7, 10 winding coil transfer conductor 16,20 Thermal release adhesive sheet 18 PET film

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hironobu Chiba             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Osamu Makino             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5E062 DD04

Claims (2)

[Claims] 1. A step of forming a mask layer having a pattern defining an exposed portion of a surface of the base plate on a conductive base plate, and the mask layer being substantially provided on the exposed portion of the base plate. Transfer including a step of forming a transfer conductor by an electroforming method using a plating liquid that does not deform mechanically, and a step of transferring the transfer conductor to a transfer target without peeling the mask layer Method of manufacturing conductor. 2. A step of forming a mask layer having a pattern defining an exposed portion of the surface of the base plate on a conductive base plate, and the mask layer being substantially provided on the exposed portion of the base plate. Forming a transfer conductor by an electroforming method using a plating liquid that does not deform mechanically, and transferring the transfer conductor without peeling off the mask layer to form a transfer conductor on the first insulator green sheet. A method of manufacturing a green sheet laminate, comprising: a step of forming a transfer conductor; and a step of providing a second insulator green sheet on a surface of the first insulator green sheet having the transfer conductor.