JPH0845765A - Manufacture of multilayer electronic component - Google Patents

Abstract

PURPOSE:To prevent generation of discontinuity and cracks fin the interlayer connection conductor part of a laminate, by forming a non-printing part in a land part, so as to correspond with a part where through hole conductor passes around the back side of a ceramic green sheet. CONSTITUTION:When an inner electrode pattern 15 is printed on a ceramic green sheet 11a by using conductive paste, through hole conductor 13 is formed in the part of a through hole 12, so as to be continuous with the inner electrode pattern 15. On the other hand, in a ceramic green sheet 11b on which the green sheet 11a is laminated, a land part 14 is formed so as to correspond with the position of the through hole conductor 13, and receives it. The land part 14 is formed so as to be continuous with the inner electrode pattern 15 printed on the ceramic green sheet 11b. A non-printing part 16 where the conductive paste is not printed is formed in the land part 14.

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 laminated electronic component such as a laminated chip inductor or a multilayer wiring board having internal electrodes connected through through-hole conductors.

[0002]

2. Description of the Related Art For example, in a multilayer chip inductor, a ceramic green sheet is prepared by thinly forming a ceramic slurry in which magnetic ceramic powder or the like is dispersed in an organic binder, and a conductive paste is printed on the ceramic green sheet by screen printing or the like. An internal electrode pattern is formed, a predetermined number of the ceramic green sheets are laminated, and the internal electrodes on each ceramic green sheet are connected via a through-hole conductor. This also applies to a multilayer wiring board such as a hybrid integrated circuit device. The internal electrodes, which are the circuit patterns described on the ceramic green sheets, are connected through the through holes between the laminated ceramic green sheets. .

FIG. 11 shows a cross section of the through-hole conductor 3 of such a ceramic green sheet 1a, 1b and a land portion 4 which receives it, and FIG. 12 shows a land portion 4.
Shows the plane. Through holes 2 are pre-drilled at predetermined positions of the ceramic green sheet 1a, and when the internal electrode pattern 5 is printed on the ceramic green sheet 1a with a conductive paste, the through hole conductor 3 is formed continuously with the internal electrode pattern 5. To be done. The through-hole conductor 3 wraps around from the front surface side of the ceramic green sheet 1a to the back side through the peripheral wall of the through hole 2, and the through hole 3 is formed on the back surface of the ceramic green sheet 1a.
Conductive paste is attached around the.

On the other hand, this ceramic green sheet 1a
The ceramic green sheet 1b laminated with is formed with a land portion 4 corresponding to the position of the through-hole conductor 3 to receive it. The land portion 4 is a flat conductor film which is printed on the ceramic green sheet 1b and has a diameter sufficiently larger than the diameter f of the portion of the through hole 3 which extends around the back side of the ceramic green sheet 1a.

Ceramic green sheets 1a and 1b having such through-hole conductors 3 and lands 4 respectively.
After being stacked, they are heated and pressed in the stacking direction to be pressure bonded. At this time, the through hole 3 and the land portion 4 are integrated, and the internal electrode patterns 5 on the ceramic layers respectively formed by the upper and lower ceramic green sheets 1a and 1b are connected to each other. Although only two ceramic green sheets 1a and 1b are shown in FIG. 11, in reality, many ceramic green sheets 1a and 1b are laminated simultaneously. Ceramic green sheet 1
FIG. 13 shows a cross section of the through-hole conductor 3 in the laminated body in which a and 1b are laminated.

[0006]

In the conventional method for manufacturing a laminated electronic component, assuming that the thickness of the ceramic green sheet 1a is a and the average film thickness of the internal electrode patterns is b, the internal electrode patterns 15 are printed. The total thickness of the ceramic green sheet 1a in the portion where it is is a + b. Of these, the total thickness of the ceramic green sheet 1a is about a + 2b, particularly in the portion around the through hole 2 where the conductor wraps around the back side of the ceramic green sheet 1a.
And the thickest. On the other hand, the through hole 2 has a thickness of zero.

As described above, since there is a large difference in thickness between the through hole 2 and the peripheral portion thereof, when the ceramic green sheets 1a and 1b are laminated and pressure-bonded, a large pressure difference partially occurs. The conductive paste escapes from the high pressure area to the low pressure area. Therefore, as shown in FIG. 13, in the laminated body 7, a constriction n is formed between the interlayer connection conductor 8 formed by the through-hole conductor 3 and the land portion 4 and the conductor 9 in the internal electrode 5. Occurrence occurs, disconnection occurs at this portion, and the resistance value increases.

Further, when laminated, stress may be concentrated on a portion corresponding to the thickest portion of the ceramic green sheet 1a of the laminated body, and fine cracks t may occur inside the laminated body. Therefore, there are problems that the manufactured laminated electronic component has a high internal resistance and that predetermined characteristics cannot be obtained. In view of the problems in the conventional method for manufacturing a laminated electronic component, an object of the present invention is to provide a method for manufacturing a laminated electronic component in which disconnection and cracks are less likely to occur in the interlayer connection conductor portion of the laminate.

[0009]

In the present invention, in order to achieve the above-mentioned object, the film thickness of the conductor of the land portion 14 of the internal electrode pattern 15 is not made uniform, but the film thickness is changed depending on the place, and when the film is laminated. By eliminating the variation in pressure, the conductor flow inside the laminate 17 is suppressed, extreme constriction does not occur, and stress is prevented from concentrating at specific points during lamination and pressurization. It is a thing.

That is, in the method for manufacturing a laminated electronic component according to the present invention, a step of molding ceramic into a sheet to obtain ceramic green sheets 11a and 11b, and the through hole 1 in the ceramic green sheets 11a and 11b.
Step of forming 2 and ceramic green sheet 11
a step of forming internal electrode patterns 15 and through-hole conductors 13 on the surfaces of a and 11b with a conductive paste in accordance with a predetermined pattern, and ceramic green sheets 11a, 1
1b is laminated and the internal electrode patterns 15 of the adjacent ceramic layers of the laminated body 17 are electrically connected through the through-hole conductors 13 in order to manufacture a laminated electronic component.
Of the internal electrode pattern 15 formed on the surface of b, at least the portion where the through hole conductor 13 is wrapped around the back side of the ceramic green sheet 11a in the land portion 14 that receives the through hole conductor 13 of the other ceramic green sheet 11a. The non-printed portion 16 on which the conductive paste is not printed is formed corresponding to the above.

In this case, the non-printed portion 16 of the land portion 14 of the internal electrode pattern 15 may have a ring shape or a circular shape. Furthermore, in the method for manufacturing a laminated electronic component according to another embodiment of the present invention, in manufacturing the laminated electronic component in the above-described steps, the other internal electrode patterns 15 formed on the surfaces of the ceramic green sheets 11a and 11b are Ceramic green sheet 11a
In the land portion 14 for receiving the through-hole conductor 13, the thick film portion 20 having a thicker printed thickness of the conductive paste than the other portion is formed corresponding to the portion of the through hole 12.

[0012]

In the first method for manufacturing a laminated electronic component according to the present invention, in the ceramic green sheet 11a having the through-hole conductor 13 of the internal electrode 15, the portion having the largest total thickness, that is, the through-hole conductor 13 is the ceramic green. The non-printed portion 16 on which the conductive paste is not printed is formed on the land portion 14 corresponding to the portion that wraps around the back side of the sheet 11a.
The total thickness on the b side was reduced. As a result, the variation in pressure between the through-hole conductor 13 and the land 14 when the ceramic green sheets 11a and 11b are stacked is reduced, and the flow of the conductive paste inside the stacked body is less likely to occur. As a result, the interlayer connection conductor 18 inside the laminated body 17
The extreme constriction is eliminated, and the conductor is not broken or the resistance is not increased. Further, stress is less likely to be concentrated at a specific place during stacking, and cracks are less likely to occur inside the stack.

Further, in the second method for manufacturing a laminated electronic component according to the present invention, the portion of the ceramic green sheet 11a having the smallest total thickness, that is, the through hole 1.
A thick film portion 20 having a particularly thick film thickness of the conductive paste was formed on the land portion 14 corresponding to the second portion. Therefore, when the ceramic green sheets 11a and 11b are laminated, the pressure variation between the through-hole conductor 13 and the land portion 14 becomes small, and the conductor is not broken or the resistance is not increased.

[0014]

Embodiments of the present invention will now be described specifically and in detail with reference to the drawings. FIG. 10 shows the ceramic green sheets 11 and 11 of the multilayer chip inductor.
It is a conceptual diagram which shows the laminated structure of. Thin ceramic green sheets 11, 11 ... Are made by means of a doctor blade method or the like using a ceramic slurry in which magnetic powder such as ferrite powder is dispersed in a binder. After punching through holes 12, 12 ... In advance at predetermined positions of these ceramic green sheets 11, 11, ..., Circular internal electrode patterns 15a, 15b, 15c, 15d, 15
e and 15f are printed, respectively, and the through hole 1
The through-hole conductors 13, 13 ... Are printed on 2, 12 ,.

An appropriate number of sets of ceramic green sheets 11, 11 ... Having internal electrode patterns 15a, 15b, 15c, 15d are prepared according to the required number of coil turns, and these are sequentially laminated. .. are laminated on both sides of the ceramic green sheets 11, 11 ... In place of the conductor 15a, the internal electrode patterns 15e and 15f having the internal conductor lead portions 25 and 26 are printed. Then, the ceramic green sheets 27 and 28 on which the internal electrode patterns are not printed are laminated on both sides as protective layers.

Then, this laminated body is pressure-bonded and fired to obtain a fired magnetic body laminated body 11. A conductive paste is applied to both end faces of the laminated body 11 and baked to form external electrodes that come into contact with the internal conductor lead portions 17 and 18 and conduct electricity. This completes the laminated ceramic inductor. Although FIG. 10 shows the laminated structure of only one monolithic ceramic inductor, actually, the ceramic green sheets printed with the internal electrode patterns for a plurality of monolithic ceramic inductors are laminated, and then the laminated body is formed. It is cut in the vertical and horizontal directions to separate into individual laminates, which are then fired.

FIG. 1 shows a cross section of the through-hole conductor 13 of the ceramic green sheets 11a and 11b and the land portion 14 that receives it, and FIG. 2 shows a plane of the land portion 14. When the internal electrode pattern 15 is printed on the ceramic green sheet 11a with the conductive paste, the through-hole conductor 13 is formed in the portion of the through hole 12 which is continuous with the internal electrode pattern 15. This through hole 13 is a ceramic green sheet 11a.
Wraps around from the front surface side to the back side through the peripheral wall of the through hole 12, and the conductive paste is attached to the periphery of the through hole 13 on the back surface of the ceramic green sheet 11a.

On the other hand, this ceramic green sheet 11
In the ceramic green sheet 11b laminated with a,
A land portion 14 is formed corresponding to the position of the through-hole conductor 13 to receive it. This land part 14
Is formed continuously with the internal electrode pattern 15 printed on the ceramic green sheet 11b, and has an outer diameter that is sufficiently larger than the diameter f of the portion of the through hole 13 that wraps around the back side of the ceramic green sheet 11a. It has a conductor film.

In the land portion 14, there is a non-printing portion 16 on which the conductive paste is not printed.
A conductive paste is printed in a circular shape in FIG. Therefore, the non-printing portion 16 has a ring shape. The outer diameter g and the inner diameter h of the non-printed portion 16 are the inner diameter d of the through-hole conductor 13, the diameter c of the through hole 12, the outer diameter f of the conductive paste wrapping around the back surface of the ceramic green sheet 11a, and the maximum thickness portion thereof. Diameter e and f>g> e, e>h> d
It has a relationship of.

A ceramic green sheet 11a having such through-hole conductors 13 and lands 14 respectively,
After being stacked, 11b is heated and pressed in the stacking direction to be pressure bonded. At this time, the through hole 13
And the land portion 14 are integrated, and the internal electrode patterns 15 on the ceramic layers formed by the upper and lower ceramic green sheets 11a and 11b are connected to each other.
In this embodiment, since there is a non-printed portion 16 on the side of the ceramic green sheet 11b corresponding to the portion where the total thickness of the ceramic green sheet 11a is thickest, there is little variation in pressure during lamination, and the conductive paste during lamination is small. Flow and stress concentration at specific locations are unlikely to occur.

Therefore, as shown in FIG. 3, a laminated body 17 in which the ceramic green sheets 11a and 11b are laminated.
In the inside, the extreme constriction of the interlayer connection conductor 18 formed by the through hole conductor 13 and the conductor of the land portion 14 is eliminated, and disconnection between the internal electrode 19 and the interlayer connection conductor 18 does not occur. Also, cracks are less likely to occur. Although only two ceramic green sheets 11a and 11b are shown in FIG. 1, it goes without saying that a plurality of ceramic green sheets 11, 11 ... Yes.

Next, the embodiment shown in FIGS. 4 and 5 will be described. In this embodiment, the non-printed portion 16 is formed at the center of the land portion 14 of the internal electrode pattern 15 in the above-described embodiment. However, the conductive paste is not printed in the non-printed portion 16. Therefore, the non-printed portion 16 of the land portion 14 in this embodiment is different from the above-described embodiment in that it is circular.

Such a ceramic green sheet 11
In the laminated body 17 obtained by laminating a and 11b, the central portion of the interlayer connection conductor 18 formed by the through-hole conductor 13 and the land portion 14 becomes slightly thin as shown in FIG.
There is less constriction around it than the conventional one. Therefore, the disconnection between the internal electrode 19 and the interlayer-connector conductor 18 does not occur, and cracks hardly occur.

Next, the embodiment shown in FIGS. 7 and 8 will be described. In this embodiment, the thickness of the conductive paste is particularly greater in the center of the land portion 14 of the internal electrode pattern 15 than in other portions of the land portion 14. A thick thick film portion 20 is formed. Such a thick film portion 20 is formed, for example, by applying the conductive paste evenly to the land portion 14, drying it, and then applying the conductive paste only to the central portion of the land portion 14 again.

The diameter i of the thick film portion 20 is equal to that of the through hole 1.
It is preferable that the diameter is substantially equal to the diameter d of 2, and is larger than the inner diameter d of the through-hole conductor 13 and smaller than the diameter e of the maximum thickness portion of the conductive paste that wraps around the back surface of the ceramic green sheet 11a. In addition, the film thickness of the thick film portion 20 and the land portion 14
The difference j from the film thickness of other portions is preferably as large as possible without exceeding the total thickness of the ceramic green sheet 11a including the through-hole conductor 13.

Such a ceramic green sheet 11
In the laminated body 17 obtained by laminating a and 11b, the central portion of the interlayer connecting conductor 18 formed by the through hole conductor 13 and the land portion 14 becomes thicker as shown in FIG. There are few waists around. Therefore, the disconnection between the internal electrode 19 and the interlayer connection conductor 18 does not occur.

Next, a more specific embodiment of the present invention will be described. (Example 1) Ferrite powder, which is an element material, is formed into a sheet by using a binder containing polyvinyl butyral as a main component. Further, Ag powder, which is an internal conductor material, is kneaded with a binder made of a resin such as a cellulosic resin and a solvent such as butyl carbitol acetate to prepare a conductive paste.

Next, as shown in FIG. 10, a ceramic green sheet 1 having through holes 12 provided at predetermined positions.
The above-mentioned conductive paste is printed on Nos. 1, 11, ... To form circular internal electrode patterns 15a, 15b, 15c, 15d. Through-hole conductor 1 of this internal electrode pattern
3 and the land portion 14 for receiving it are shown in FIGS. In this embodiment, the ceramic green sheets 11a, 11
The thickness a of b was 50 μm, and the printed thickness b of the internal electrode pattern 15 was 30 μm. Further, each dimension shown in FIG.
250 μm, d = 210 μm, e = 290 μm, f = 3
70 μm, g = 350 μm, h = 250 μm.

The thus obtained ceramic green sheets 11, 11 ... Are laminated as shown in FIG. 10, and a plurality of ceramic green sheets 27, 28 on which conductors are not printed are laminated as protective layers on the upper and lower surfaces of the laminated sheets. . The product thus laminated is 90 ° C., 400 kg /
Thermocompression bonding with cm ² . Next, the obtained laminated body is provided with internal conductor lead portions 25 of the conductors 15e and 15f on its end faces.
It is cut to a predetermined size so that 26 is exposed. The cut chips are fired at a temperature of 900 ° C. in the air for 1 hour.

Further, Ag paste for external electrodes is applied to both end faces of the thus obtained chip and baked at a temperature of 600 ° C. for 20 minutes in the atmosphere to form external electrodes which are electrically connected to the internal conductor drawing portion, The multilayer chip inductor is completed. The multilayer chip inductor thus obtained is
When we randomly picked out 00 pieces and measured the DC resistance between the external electrodes, the average was 0.49Ω and the standard deviation was 0.02.
Ω. Furthermore, when these multilayer chip inductors were longitudinally cut in the stacking direction and the total stack thickness was measured, the total stack thickness of the portion without internal electrodes was 1940 μm, and the total stack thickness of the portion where the through-hole conductor and the land portion overlap each other. 271
It was 0 μm. Further, there were two cracks inside the laminate, that is, the crack occurrence rate was 2%.

(Embodiment 2) In Embodiment 1, the shape of the land portion 14 of the internal electrode 15 of the ceramic green sheet 11b is as shown in FIGS. 4 and 5, and g = 330 μm.
A multilayer chip inductor was produced in the same manner as in Example 1 except that the above was adopted. 100 multilayer chip inductors thus obtained were randomly taken out, and the DC resistance value between the external electrodes was measured. The average was 0.50Ω and the standard deviation was 0.02Ω.

(Embodiment 3) In Embodiment 1, the shape of the land portion 14 of the internal electrode 15 of the ceramic green sheet 11b is as shown in FIGS. 7 and 8, and i = 240 μm.
A multilayer chip inductor was produced in the same manner as in Example 1 except that m and j = 70 μm. 100 multilayer chip inductors thus obtained were randomly taken out, and the DC resistance value between the external electrodes was measured. The average was 0.49Ω and the standard deviation was 0.02Ω.

(Comparative Example) In Example 1, the land portion 1 of the internal electrode 15 of the ceramic green sheet 11b was used.
4 except that the shape of 4 is as shown in FIGS. 11 and 12.
A multilayer chip inductor was produced in the same manner as in Example 1. The multilayer chip inductor thus obtained is
When they were taken out randomly, and the DC resistance value between the external electrodes was measured, the average was 0.53Ω and the standard deviation was 0.03Ω.

Although all of the above-described embodiments were methods for manufacturing a monolithic ceramic inductor, the present invention is not limited to monolithic ceramic inductors, and is a multi-layer electronic component such as a composite LC component or a multi-layer circuit board, which is As long as the internal electrodes of each layer are connected by the hole conductor, it is obvious that the same can be applied.

[0035]

As described above, according to the present invention, there is provided a method of manufacturing a laminated electronic component in which the conductor is not easily broken or the resistance in the laminate is not increased, and the cracks are not easily generated in the laminate. be able to. As a result, a laminated electronic component having stable characteristics can be manufactured with high yield.

[Brief description of drawings]

FIG. 1 is an enlarged longitudinal sectional view of essential parts of a through hole conductor and a land portion of an internal electrode pattern of a ceramic green sheet used in a method for manufacturing a laminated electronic component according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view of a main part of a land portion of an internal electrode pattern of a ceramic green sheet used in the method for manufacturing a laminated electronic component according to the example.

FIG. 3 is a vertical cross-sectional side view of essential parts of a portion corresponding to a through-hole conductor and a land portion of an internal electrode pattern of a laminated body obtained by the method for manufacturing a laminated electronic component according to the same example.

FIG. 4 is an enlarged vertical cross-sectional view of a through hole conductor and a land portion of an internal electrode pattern of a ceramic green sheet used in a method for manufacturing a laminated electronic component according to another embodiment of the present invention.

FIG. 5 is an enlarged plan view of a main part of a land portion of an internal electrode pattern of a ceramic green sheet used in the method for manufacturing a laminated electronic component according to the example.

FIG. 6 is a vertical cross-sectional side view of a main portion of a portion corresponding to a through-hole conductor and a land portion of an internal electrode pattern of a laminated body obtained by the method for manufacturing a laminated electronic component according to the same example.

FIG. 7 is an enlarged longitudinal sectional view of a through hole conductor and a land portion of an internal electrode pattern of a ceramic green sheet used in a method of manufacturing a laminated electronic component according to still another embodiment of the present invention.

FIG. 8 is an enlarged plan view of a main part of a land portion of an internal electrode pattern of a ceramic green sheet used in the method for manufacturing a laminated electronic component according to the example.

FIG. 9 is a vertical cross-sectional side view of essential parts of a portion corresponding to a through-hole conductor and a land portion of the internal electrode pattern of the multilayer body obtained by the method for manufacturing a multilayer electronic component according to the example.

FIG. 10 is an exploded perspective view conceptually showing the laminated structure of the ceramic green sheets of the laminated ceramic inductor.

FIG. 11 is an enlarged vertical cross-sectional view of a main part of a through hole conductor and a land portion of an internal electrode pattern of a ceramic green sheet used in a method for manufacturing a laminated electronic component according to a conventional example.

FIG. 12 is an enlarged plan view of a main part of a land portion of an internal electrode pattern of a ceramic green sheet used in the method for manufacturing a laminated electronic component according to the conventional example.

FIG. 13 is a vertical cross-sectional side view of essential parts of a portion corresponding to a through-hole conductor and a land portion of an internal electrode pattern of a laminated body obtained by the method for manufacturing a laminated electronic component according to the conventional example.

[Explanation of symbols]

 11 ceramic green sheet 11a ceramic green sheet 11b ceramic green sheet 12 through hole 13 through hole conductor of internal electrode pattern 14 land portion of internal electrode pattern 15 internal electrode pattern 15a internal electrode pattern 15b internal electrode pattern 15c internal electrode pattern 15d internal electrode pattern 15e Internal electrode pattern 15f Internal electrode pattern 16 Non-printed part of land 20 Thick film part of land

Claims (4)

[Claims] 1. A step of forming ceramic into a sheet to obtain ceramic green sheets (11a) and (11b), and the ceramic green sheets (11a) and (11).
The step of forming a through hole (12) in (b), and the internal electrode pattern (15) and the through hole conductor (13) are formed on the surfaces of the ceramic green sheets (11a) and (11b) according to a predetermined pattern with a conductive paste. And the ceramic green sheets (11a) and (11b)
And a step of electrically connecting the internal electrode patterns (15) of the adjacent ceramic layers (17) of the laminate through the through-hole conductors (13), the ceramic green sheet Of the internal electrode patterns (15) formed on the surfaces of (11a) and (11b), at least the through hole is formed in the land portion (14) that receives the through hole conductor (13) of the other ceramic green sheet (11a). Conductor (1
3) A method for manufacturing a laminated electronic component, characterized in that a non-printed portion (16) on which a conductive paste is not printed is formed corresponding to a portion around the back side of the ceramic green sheet (11a). 2. The laminated electronic component according to claim 1, wherein the non-printed portion (16) of the land portion (14) of the internal electrode pattern (15) is formed in a ring shape. Method. 3. The method for manufacturing a laminated electronic component according to claim 1, wherein the non-printed portion (16) of the land portion (14) of the internal electrode pattern (15) is formed in a circular shape. Method. 4. A step of molding ceramic into a sheet to obtain ceramic green sheets (11a) and (11b), and the ceramic green sheets (11a) and (11).
The step of forming a through hole (12) in (b), and the internal electrode pattern (15) and the through hole conductor (13) are formed on the surfaces of the ceramic green sheets (11a) and (11b) according to a predetermined pattern with a conductive paste. And the ceramic green sheets (11a) and (11b)
And a step of electrically connecting the internal electrode patterns (15) of the adjacent ceramic layers of the laminate (17) through the through-hole conductors (13). Among the internal electrode patterns (15) formed on the surfaces of (11a) and (11b), the through hole (14) is formed in the land portion (14) that receives the through hole conductor (13) of the other ceramic green sheet (11a). A method of manufacturing a laminated electronic component, characterized in that a thick film portion (20) having a printed thickness of a conductive paste thicker than other portions is formed corresponding to the portion (12).