JP4479062B2 - Method for producing green sheet laminate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a green sheet laminate used for forming a chip-type electronic component such as a multilayer chip inductor.
[0002]
[Prior art]
Hereinafter, a conventional method for producing a green sheet laminate will be described with reference to the drawings.
[0003]
Conventionally, the manufacturing method of a green sheet laminated body has been described in JP-A-8-162352.
[0004]
FIG. 3 is a cross-sectional view showing a method for producing a base plate provided with a transfer conductor, and is also a diagram showing the basic principle of the method for producing a transfer conductor.
[0005]
First, as shown in FIG. 3 (a), a flexible stainless steel base plate 3 is used. The base plate 3 is degreased with an alkaline cleaner or the like, then washed with water and dried.
[0006]
Next, as shown in FIG. 3B, a mask layer 4 is formed by spin-coating a liquid photoresist on the base plate 3 and drying it.
[0007]
Next, as shown in FIG. 3C, the mask layer 4 is irradiated with parallel ultraviolet rays through a photomask 6 formed of chromium or the like.
[0008]
Thereafter, as shown in FIG. 3D, after developing with an alkali developer, post-baking is performed, whereby the photomask 6 is peeled off to obtain a mask layer 4 having a predetermined pattern. This mask layer 4 can be used repeatedly.
[0009]
Next, as shown in FIG. 3E, the release layer 2 is formed by performing Ag strike plating on the exposed portion of the base plate 3.
[0010]
Subsequently, as shown in FIG. 3 (f), thick Ag plating is performed to form a transfer conductor 5 so as to be electrically connected to the adjacent mask layer 4 on the upper surface of the release layer 2. At this time, the Ag plating film formed above the mask layer 4 is also formed in the lateral direction. As a result, the line width of the transfer conductor 5 is the same as that of the base plate 3 defined by the mask layer 4. It becomes wider than the width of the exposed part.
[0011]
Below, the manufacturing method of the green sheet laminated body which has a some conductor layer using the base plate provided with the conductor for a transfer mentioned above is demonstrated, referring FIG. FIG. 4 is a diagram showing a method for producing a green sheet laminate. The obtained transfer conductor 5 is transferred to an insulator green sheet as follows.
[0012]
First, as shown in FIG. 4A, the thermal foam sheet 13 is pasted on the pallet plate 10. A green sheet laminate 1 is formed by stacking four magnetic green sheets having a thickness of about 100 μm on the thermal foam sheet 13. At this time, the thickness of the green sheet laminate can be changed as necessary. The thickness of each green sheet may be changed, or the number of green sheets to be stacked may be changed.
[0013]
Next, using a base plate provided with a transfer conductor having a conductive release layer 2, a transfer conductor 5, and a mask layer 4 on the base plate 3 obtained in the steps of FIGS. As shown in FIG. 4B, the transfer conductor 5 is bonded to the green sheet laminate 1 so as to be in contact with the green sheet laminate 1. Thereafter, heating, pressurizing, and cooling are performed under conditions of about 105 ° C., about 5 seconds, and a press pressure of about 8 MPa. At this time, the portion of the transfer conductor 5 that protrudes from the mask layer 4 is cut into the green sheet laminate 1, heated, pressurized, and then cooled, so that the transfer conductor 5 becomes green sheet laminate 1. It is fixed to.
[0014]
Next, as shown in FIG. 4 (c), the transfer conductor 5 and the conductive release layer 2 are separated from the green sheet laminate 1 by peeling the base plate 3 including the transfer conductor from the green sheet laminate 1. 1 is transferred. At this time, the base plate 3 has flexibility and is deformed as shown in FIG. 4C, so that it can be easily peeled off. Thereafter, the base plate 3 provided with the transfer conductor described with reference to FIG. 3 can be used repeatedly by performing the steps after the step of FIG. In this way, the first conductor layer 41 in which the transfer conductor 5 is formed in a predetermined pattern shape on the green sheet laminate 1 is obtained.
[0015]
Next, an intermediate layer 42 for electrically connecting the first conductor layer 41 and a second conductor layer 43 described later is laminated. As shown in FIG. 4D, the intermediate layer 42 has a through hole 9 in which the magnetic green sheet 8 is filled with Ag paste. The position is determined and laminated on the first conductor layer 41 so as to obtain an electrical contact between the first conductor layer 41 and the second conductor layer 43 (not shown in the figure). Thereafter, the intermediate layer 42 is fixed to the first conductor layer 41 by applying pressure at about 105 ° C. and about 8 MPa for about 2 seconds.
[0016]
The intermediate layer 42 can also be formed by the following method, for example. A through hole 9 is mechanically formed at a predetermined position of the magnetic green sheet 8 using a puncher or the like. This is a method of filling the through holes 9 with Ag paste using a screen printing method.
[0017]
Next, as shown in FIG. 4E, the second conductor layer 43 is laminated on the intermediate layer 42 by the same method as the first conductor layer 41 which is the previous step. A green sheet laminate having an arbitrary number of conductor layers can be formed by alternately repeating the lamination of the intermediate layer 42 and the conductor layer composed of the transfer conductor 5 having a predetermined pattern shape.
[0018]
Finally, as shown in FIG. 4 (f), after forming the required number of conductor layers, the insulator green sheet laminate 1 is laminated on the uppermost layer.
[0019]
In the step of laminating the green sheet laminate 1, the conductor layer, and the intermediate layer 42 described above, there is a method using a positioning pin as a method for positioning the through-holes of the transfer conductor 5 and the intermediate layer 42 of the conductor layer.
[0020]
FIG. 7 is a perspective view of laminating a green sheet on a lower mold, which is a main part of a green sheet laminating apparatus for a green sheet laminate.
[0021]
As shown in FIG. 7, a pair of positioning pins 22 are provided in the laminated lower mold 21, and a pair of positioning holes are provided in each of the base plate 3 and the green sheet 8 so as to match the pitch. By aligning the positioning holes of the pallet plate 10, the base plate 3, and the green sheet 8 with the positioning pins of the stacked lower mold in the procedure of FIG. 4, the positions of the respective layers can be aligned.
[0022]
In the above manufacturing method, a plurality of conductor patterns are generally formed on one sheet in order to obtain a plurality of multilayer ceramic chip inductors simultaneously in order to improve manufacturing efficiency. Accordingly, it is cut into individual multilayer chip inductors and then fired at 850 to 1000 ° C. for about 1 to 2 hours.
[0023]
Finally, a silver alloy-based extraction electrode is formed so as to be connected to the inner coiled coil-shaped transfer conductor on the opposing outer piece of the chip, and sintered at about 600 to 850 ° C. The external electrode 12 shown in 9 is formed. Further, Ni, solder or the like is plated on the external electrode 12.
[0024]
[Problems to be solved by the invention]
The conventional method for manufacturing a green sheet laminate configured as described above has a problem that a conductor pattern transfer defect occurs.
[0025]
The cause of the conductor pattern transfer failure will be described with reference to FIG.
[0026]
As shown in FIG. 10A, the base plate 3 having the transfer conductor is placed on the positioning pin 22 of the lower die 21 on the green sheet laminate 1 in which four magnetic green sheets having a thickness of 100 μm are stacked. Place the positioning holes of the base plate 3 together.
[0027]
Next, as shown in FIG. 10B, the upper mold 23 heated to 105 ° C. by the cartridge heater 24 is lowered and pressurized.
[0028]
At this time, as shown in FIG. 10 (c), heat is transferred to the base plate 3 and thermally expands, and is struck against the positioning pins 22, so that the base plate 3 warps upward.
[0029]
Subsequently, as shown in FIG. 10 (d), when pressurization is completed and the upper mold 23 is raised, the base plate 3 that has been in close contact with the green sheet laminate 1 floats, and before cooling, Since the base plate 3 is separated from the green sheet laminate 1 and the transfer conductor 5 is not fixed to the green sheet laminate 1, a conductor pattern transfer failure occurs.
[0030]
An object of the present invention is to solve the above-mentioned conventional problems, and to provide a method for producing a green sheet laminate with less occurrence of conductor pattern transfer failure.
[0031]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, the green sheet and the base plate are positioned by positioning means before the base plate having the transfer conductor and the green sheet are pressed, and the base plate and the green sheet are pressed. In doing so, the base plate releases the positioning by the base plate positioning means , and the green sheet also releases the positioning from the green sheet positioning means .
[0032]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 of the present invention is to press a base plate having a transfer conductor and a green sheet, and transfer the transfer conductor to the green sheet to form a conductor having a predetermined shape. The green sheet and the base plate are positioned by positioning means before pressing the base plate having the transfer conductor and the green sheet, and at least when the base plate and the green sheet are pressed, the base plate The green sheet laminate manufacturing method is characterized in that the positioning is released from the positioning means of the base plate and the positioning of the green sheet is also released from the positioning means of the green sheet, wherein the positioning means is a pin Each of the base plate and the green sheet has a positioning hole, and the pin has the base. The positioning of the base plate and the green sheet is performed by engaging the positioning holes of the plate and the green sheet, the positioning of the base plate is released by removing the pin from the positioning hole of the base plate, and the pin is The method includes a step of releasing the positioning of the green sheet by removing it from the positioning hole of the green sheet .
[0033]
Thereby, at least until the base plate and the green sheet are pressed, since the base plate is positioned by the positioning means, the position of the base plate is not shifted, and after the base plate and the green sheet are pressed, Since the positioning of the base plate is released, the positioning is released before heat is transmitted to the base plate, and with a simple configuration, it is possible to obtain a green sheet laminate by preventing the base plate from warping. .
[0034]
Hereinafter, the manufacturing method of the green sheet laminated body in Embodiment 1 of this invention is demonstrated, referring drawings. In the drawings used in the following description, for the sake of simplicity, one laminated body for forming one inductor is illustrated. However, in actual production, a plurality of inductors can be formed by forming a plurality of laminated bodies on a single pallet plate and separating them after the laminated bodies are completed.
[0035]
FIG. 2 is an exploded perspective view of the multilayer chip inductor according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing a method for manufacturing a transfer conductor. 2 and 3, the same components as those in the conventional technique are denoted by the same reference numerals, and detailed description thereof is omitted.
[0036]
First, as shown in FIG. 3 (a), a flexible stainless steel base plate 3 is used. The base plate 3 is degreased with an alkaline cleaner or the like, then washed with water and dried.
[0037]
Next, as shown in FIG. 3B, a mask layer 4 having a thickness of 2 to 10 μm is formed on the base plate 3 by spin-coating a liquid photoresist and drying it.
[0038]
Next, as shown in FIG. 3C, the mask layer 4 is irradiated with parallel ultraviolet rays through a photomask 6 formed of chromium or the like.
[0039]
Thereafter, as shown in FIG. 3D, after development using an alkali developer, post-baking is performed at about 150 ° C. for 30 minutes to form a mask layer 4 having a predetermined pattern. This mask layer 4 can be used repeatedly.
[0040]
Next, as shown in FIG. 3E, the release layer 2 is formed by performing Ag strike plating on the exposed portion of the base plate 3.
[0041]
Subsequently, as shown in FIG. 3 (f), thick transfer Ag plating is performed to form a transfer conductor 5 having a thickness of about 20 to 25 μm so as to be electrically connected to the adjacent mask layer 4 on the upper surface of the release layer 2. At this time, the Ag plating film formed above the mask layer 4 is also formed in the lateral direction. As a result, the line width of the transfer conductor 5 is the same as that of the base plate 3 defined by the mask layer 4. It becomes wider than the width of the exposed part.
[0042]
Below, the manufacturing method of the green sheet laminated body which has a some conductor layer using the base plate provided with the conductor for a transfer mentioned above is demonstrated, referring drawings.
[0043]
FIG. 1 is a view showing a green sheet laminating apparatus used in the method for producing a green sheet laminated body according to Embodiment 1 of the present invention. The obtained transfer conductor 5 is transferred to an insulator green sheet as shown in FIGS.
[0044]
In FIG. 1, 21 is a lower mold | type. Reference numeral 22 denotes a pair of positioning pins (positioning means) provided on the lower die 21 and capable of sliding up and down. A compression spring 25 lowers the positioning pin 22 downward. A cam 26 is provided below the compression spring 25 and moves the positioning pin 22 up and down. An air cylinder 27 drives the cam 26. Reference numeral 23 denotes an upper mold provided above the lower mold 21 so as to be spaced apart. A cartridge heater 24 is provided on the upper mold 23 and heats the temperature of the upper mold 23 to about 105 ° C.
[0045]
A method for manufacturing a green sheet laminate using the green sheet laminating apparatus configured as described above will be described below.
[0046]
FIG. 7 is a perspective view in which a green sheet is laminated on a lower mold, which is a main part of the green sheet laminating apparatus for a green sheet laminate in Embodiment 1 of the present invention.
[0047]
As shown in FIG. 7, a pair of positioning holes are provided in each of the pallet plate 10, the base plate 3, and the green sheet 8 so as to match the pitch of the pair of positioning pins 22 provided in the lower mold 21. One of the pair of positioning holes provided in the pallet plate 10 and the base plate 3 is good because the elongated hole can be finely adjusted in each positioning.
[0048]
A method for producing a green sheet laminate using a pallet plate in which green sheets are laminated on the lower mold configured as described above will be described below.
[0049]
First, as shown in FIG. 7, the pallet plate 10 is placed on the lower mold 21 according to the positioning pins 22. A thermal foam sheet 13 is pasted on the pallet plate 10. The green sheet laminate 1 in which four magnetic green sheets having a thickness of 100 μm are stacked is formed on the thermal foam sheet 13. The thickness of the green sheet laminated body 1 can be changed as needed. The thickness of each green sheet may be changed, or the number of green sheets to be stacked may be changed.
[0050]
Next, the base plate 3 provided with the conductive release layer 2, the transfer conductor 5, and the transfer conductor having the mask layer 4 on the base plate 3 obtained in the steps of FIGS. As shown in FIG. 5 (a), the positioning hole of the base plate 3 is aligned with the positioning pin 22 of the lower mold 21 so that the transfer conductor 5 is in contact with the green sheet 1. .
[0051]
Next, as shown in FIG. 5B, the upper die 23 heated to 105 ° C. by the cartridge heater 24 is lowered and pressurized under a condition of a press pressure of about 8 MPa for about 5 seconds.
[0052]
Next, as shown in FIG. 6A, the positioning pin 22 is lowered at the moment when the upper mold 23 is lowered and contacts the base plate 3. At this time, since the upper mold 23 is pressed, even if the positioning pin 22 is pulled out, the position of the base plate 3 is not shifted, and since the positioning pin 22 is pulled out before the heat is transmitted to the base plate 3, the base plate 3 is not warped. . At this time, as shown in FIG. 6B, the portion protruding from the mask layer 4 of the transfer conductor 5 is digged into the green sheet laminate 1, and the pressurization is finished to raise the upper mold 23. Thereafter, the transfer conductor 5 is fixed to the green sheet laminate 1 by cooling.
[0053]
Next, as shown in FIG. 4C, the transfer conductor 5 and the conductive release layer 2 are transferred to the green sheet laminate 1 by peeling the base plate 3 on which the mask layer 4 is formed. . At this time, the base plate 3 has flexibility and is deformed as shown in FIG. 4C, so that it can be easily peeled off. Thereafter, the base plate 3 having the mask layer 4 can be used repeatedly by performing the steps after the step of FIG. In this way, the first conductor layer 41 in which the transfer conductor 5 is formed in a predetermined pattern shape on the green sheet laminate 1 is obtained.
[0054]
Next, the intermediate layer 42 for electrically connecting the first conductor layer 41 and the second conductor layer 43 to be laminated later is laminated. As shown in FIG. 4D, the intermediate layer 42 has a through hole 9 in which the magnetic green sheet 8 is filled with Ag paste. The position is determined and laminated on the first conductor layer 41 so as to obtain an electrical contact between the first conductor layer 41 and the second conductor layer 43 (not shown in the figure). Thereafter, the intermediate layer 42 is fixed to the first conductor layer 41 by applying pressure at about 105 ° C. and about 8 MPa for about 2 seconds.
[0055]
The intermediate layer 42 can also be formed by the following method, for example. A through hole 9 having a thickness of 0.1 mm is mechanically formed at a predetermined position of the magnetic green sheet 8 having a thickness of 100 μm using a puncher or the like. This is a method of filling the through holes 9 with Ag paste using a screen printing method.
[0056]
Next, as shown in FIG. 4E, the second conductor layer 43 is laminated on the intermediate layer 42 by the same method as the first conductor layer 41 which is the previous step. A green sheet laminate having an arbitrary number of conductor layers can be formed by alternately repeating the lamination of the intermediate layer 42 and the conductor layer composed of the transfer conductor 5 having a predetermined pattern shape.
[0057]
Finally, as shown in FIG. 4 (f), after forming the required number of conductor layers, the insulator green sheet laminate 1 is laminated on the uppermost layer.
[0058]
In the above manufacturing method, a plurality of conductor patterns are generally formed on one sheet in order to obtain a plurality of multilayer ceramic chip inductors simultaneously in order to improve manufacturing efficiency. Therefore, the green sheet laminate is fixed to the green sheet laminating apparatus shown in FIG. 7 and cut into individual multilayer chip inductors.
[0059]
FIG. 8 shows a cutting device used in the method for manufacturing a green sheet laminate in Embodiment 1 of the present invention .
[0060]
In FIG. 8, 31 is a cutting base, 32 is a pair of positioning pins provided on the cutting base 31, 33 is a cutting blade, 34 is a guide, 35 is a ball screw, and 36 is a rotating mechanism.
[0061]
The cutting apparatus configured as described above first positions the positioning holes of the pallet plate 10 with the positioning pins 32, and places the green sheet laminate 11 obtained in the transfer laminating process on the cutting base.
[0062]
Next, the ball screw 35 is rotated by a certain amount, the cutting base is fed at a constant pitch in the direction of the guide 34, the cutting blade 33 is lowered, and the green sheet laminate 11 is cut.
[0063]
Next, after the cutting in one direction is completed, the rotating mechanism 36 is driven to rotate the cutting base 31 by 90 °, and similarly the cutting in the 90 ° rotating direction is also performed, so that a multilayer ceramic chip inductor piece is obtained.
[0064]
Thereafter, firing is performed at about 850 to 1000 ° C. for about 1 to 2 hours.
[0065]
Finally, a silver alloy-based extraction electrode is formed so as to be connected to the inner coiled coil-shaped transfer conductor on the opposing outer piece of the chip, and sintered at about 600 to 850 ° C. The external electrode 12 shown in 9 is formed. Further, the external electrode 12 is plated with Ni, solder or the like.
[0066]
In the first embodiment of the present invention, the positioning pin is used as the positioning means. However, a positioning method using an outer portion such as a green sheet or a base plate may be used.
[0067]
Further, when pressing at least the base plate and the green sheet as in the first embodiment of the present invention, the positioning by the positioning means of the base plate is released and the positioning of the green sheet is also released. Even if the pressing direction of the base plate is a direction in which the position of the green sheet is shifted, the green sheet can be prevented from warping.
[0068]
That is, it is preferable that the upper surface and the lower surface of the green sheet are parallel and the pressing direction of the base plate is the same as the vertical direction of the upper surface of the green sheet. However, the upper surface and the lower surface of the green sheet may not be formed in parallel, or the pressing direction of the base plate may not match the vertical direction of the upper surface of the green sheet due to the accuracy of the apparatus. In this case, a force for shifting the position of the green sheet is generated by pressing the base plate. Thereby, the position of the green sheet in contact with the base plate tends to shift.
[0069]
Here, when the base plate and the green sheet are pressed, the positioning by the positioning means of the base plate is released, but when the positioning by the positioning means of the green sheet is not released, the green sheet in the part in contact with the base plate is Whereas the position tends to shift, the portion of the green sheet positioned by the positioning means does not shift. As a result, the green sheet may be deformed, and the transfer conductor may not be transferred normally.
[0070]
In the first embodiment of the present invention, when the base plate and the green sheet are pressed, the positioning by the positioning means of the base plate is released and the positioning by the positioning means of the green sheet is also released, so that such a state is prevented. can do.
[0071]
The positioning release by the positioning means is performed when “the base plate and the green sheet are pressed”, but this means that the pressing and the positioning cancellation are performed at exactly the same time. Absent. It may be after the positional relationship between the base plate and the green sheet is fixed by pressing and before the heat of the upper mold is transmitted to the base plate and the base plate is deformed by the heat. In Embodiment 1 of the present invention, the upper mold is a pressing unit that presses the base plate and the green sheet, and is also a heating unit that heats the base plate.
[0072]
Further, in Embodiment 1 of the present invention, the same positioning means is used for positioning the base plate and the green sheet, but different positioning means may be used.
[0073]
【The invention's effect】
As described above, according to the present invention, the position of the base plate is not shifted, and after the base plate and the green sheet are pressed, the positioning of the base plate is released, so that the heat is transmitted to the base plate. By canceling the positioning , the base plate does not warp with a simple configuration, and a green sheet laminate in which the transfer conductor is reliably transferred can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing a green sheet laminating apparatus according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view showing the structure of the multilayer ceramic chip inductor. FIG. 3 is a cross-sectional view showing a method for forming a transfer conductor. 4 is a cross-sectional view showing a method for producing a green sheet laminate. FIG. 5 is a cross-sectional view showing a conductor transfer method in Embodiment 1 of the present invention. FIG. 6 is a production method for fixing the transfer conductor to a green sheet. FIG. 7 is a perspective view in which green sheets are stacked on a lower mold, which is a main part of a green sheet stacking apparatus for green sheet stacks. FIG. FIG. 9 is a perspective view of a multilayer ceramic chip inductor. FIG. 10 is a diagram illustrating the cause of a defective conductor pattern transfer in a conventional transfer method. Figure [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 7 Green sheet 2 Conductive release layer 3 Base board 4 Mask layer 5 Transfer conductor 6 Photomask 8 Green sheet 9 Through hole 10 Pallet board 11 Green sheet laminated body 12 External electrode 13 Thermal foam sheet 21 Lower mold 22, 32 Locating Pin 23 Upper Die 24 Cartridge Heater 25 Compression Spring 26 Cam 27 Air Cylinder 31 Cutting Base 33 Cutting Blade 34 Guide 35 Ball Screw 36 Rotating Mechanism

Claims (1)

A base plate having a transfer conductor and a green sheet are pressed, and the transfer conductor is transferred to the green sheet to form a conductor having a predetermined shape.
Before pressing the base plate and the green sheet having the transfer conductor, the green sheet and the base plate are positioned by positioning means, and at least when pressing the base plate and the green sheet, the base plate While releasing the positioning from the positioning means of the base plate, the green sheet is also a method of manufacturing a green sheet laminate, wherein the positioning is released from the positioning means of the green sheet,
The positioning means is a pin, and each of the base plate and the green sheet has a positioning hole, and the pin engages with a positioning hole of the base plate and the green sheet to position the base plate and the green sheet. The step of releasing the positioning of the base plate by removing the pin from the positioning hole of the base plate, and the step of releasing the positioning of the green sheet by removing the pin from the positioning hole of the green sheet, A method for producing a green sheet laminate.

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