Multi layer ceramic electronic parts and manufacturing method thereof

Abstract

A multi layer ceramic electronic parts, comprises: a laminated body in which a ceramic layer and internal electrodes and are laminated one another; and external electrodes and being provided at end portions of the laminated body, in which the internal electrodes and reach to either one of at least a pair of edges of the ceramic layer opposing to each other, thereby leading out the internal electrodes and to end surfaces of the laminated body opposing to each other, respectively, and connecting the internal electrodes and led out to the end surfaces of the laminated body to the external electrodes and, respectively. Pillar-like ceramic portions, being continuous in a direction of thickness of a conductor film forming the external electrodes and, are scattered on the conductor film. And, the ceramic portions of the external electrodes and are so formed that they are continuous from an inner surface of the conductor film of the external electrodes and where it is in closely contact with a surface on the laminated body up to an upper surface thereof. With this multi layer ceramic electronic parts, the cracks due to heat-shock can be prevented from occurring within the laminated body, and also the property in soldering of the external electrode and can be kept in good condition.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to multi layer ceramic electronic parts having, for example, a laminated body of internal electrode patterns and ceramic layers therein, at end portions of which are provided external electrodes so as to conduct to the internal electrodes, and in particular to the multi layer ceramic electronic parts in which a material common with a ceramic material for forming the ceramic layers of the laminated body is added into at least a portion of the external electrodes, and further a manufacturing method thereof.

[0003] 2. Description of Related Art

[0004] As electronic components of a laminated type can be listed up, for example, the laminated capacitor, a laminated inductor, a laminated piezo element, a laminated filter, a ceramic multi-layer circuit board, etc.

[0005] For example, in a laminated ceramic capacitor being as the most representative one of the such laminated electronic components, a large number of layers are piled up or laminated, each having an internal electrode and made of dielectric material, wherein the above-mentioned internal electrodes are pulled out one another to the end surfaces of the laminated body opposing to each other. And, on the end surfaces, to which those internal electrodes are pulled out, are formed external electrodes, and those external electrodes are connected to the above-mentioned internal electrodes, respectively.

[0006] The above-mentioned laminated body 3 of such the laminated ceramic capacitor has a layer construction as shown in FIG. 3, for example. Namely, the ceramic layers 7, 7 . . . , each having the internal electrode 5 or 6 and made of dielectric material, are laminated in an order as shown in the FIG. 3, and further on both sides (i.e., upper and lower sides) thereof are piled up or laminated the ceramic layers 7, 7 . . . in plurality thereof, on which no such the electrode 5 or 6 is formed, respectively. And, upon the end portions of the laminated body 3 having such the layer structure therein, the internal electrodes 5 and 6 expose one another, and as shown in FIG. 1, the above-mentioned external electrodes 2 and 2 are formed at the end portions of this laminated body 3.

[0007] Such the laminated ceramic capacitor, ordinarily, is not manufactured one by one, as or in a unit of one part as shown in the FIG. 3, but actually is obtained with a manufacturing method which will described below. Namely, first of all, minute ceramic powder and organic binder are mixed to prepare slurry, and it is extended thinly on a carrier film made from a polyethylene terephthalate film, etc., by means of doctor blade method. Then, it is dried to be formed into a ceramic green sheet. Next, this ceramic green sheet is cut out into a desire size by a cutting head, while being mounted on the supporting sheet, and is printed with a conductive paste on one side surface thereof by a screen printing method, and is dried. With this, the ceramic green sheets 1a and 1b are obtained, on each of which plural sets of the internal electrode patterns 2a and 2b are aligned or arranged in the vertical and horizontal directions, as shown in FIG. 4. Next, plural pieces of the ceramic green sheets 1a and 1b, each having the above-mentioned internal electrode patterns 2a or 2b thereon, are piled up or laminated, and further are piled a several pieces of the ceramic green sheets 1, 1 . . . having no such the internal electrode 2a or 2b, at the top and the bottom thereof. Those are suppressed to be put together, thereby to form the laminated body. Here, the above ceramic green sheets 1a and 1b are piled up one another, on which the internal electrode patterns 2a and 2b are shifted by a half of the length in a longitudinal direction thereof. After that, this laminated body is cut out into a desired size, thereby to manufacture laminated raw chips, and those raw chip are baked. In this manner are obtained the laminated bodies as shown in the FIG. 3.

[0008] Next, this baked laminated body 3 is applied with a conductor paste on both ends thereof and is baked, and on the surface of the baked conductive film is treated a plating, thereby completing the laminated ceramic capacitor formed with the external electrodes at both ends thereof, as shown in the FIG. 1.

[0009] The multi layer ceramic electronic parts, such as the laminated ceramic capacitor mentioned above, is mounted on a circuit board and is soldered at the external electrodes 2 and 2 on both ends thereof on land electrodes of the circuit board.

[0010] However, such the laminated ceramic capacitor generates thermal stress within the laminated body 3 due to heat-shock when being soldered at the external electrodes thereof or due to change of a circumference temperature under the condition of use after the soldering. With this thermal stress, in particular in an end portions of the external electrodes 2 and 2 of the laminated body 3 can easily occur cracks. The cracks occurring in the laminated body 3 bring about a lowering in insulation due to invasion of moisture inside and a lowering in statistic capacitance due to discontinuity of the internal electrodes 5 and 6, thereby causing a low reliability thereof.

[0011] Such the thermal stress causing the cracks in the laminated body occurs due to the difference in the thermal expansion ratio, between the ceramic material which is a main ingredient of forming the laminated body 3, and the conductor which is a main ingredient of forming the external electrodes 2 and 2. Then, conventionally, a measure was taken, into the conductor paste for forming the external electrodes 2 and 2 is added the ceramic material of forming the ceramic layer 7 as a common material, thereby to make small the difference between the ceramic layer 7 and the external electrodes 2 and 2 in the physical properties, such as the thermal stress therein.

[0012] However, if the common material, i.e., the ceramic material for forming the ceramic layer 7, is put or added into the conductor paste for forming the external electrodes 2 and 2 much, stickiness or adhesiveness of the external electrodes 2 and 2 onto the external electrodes 5 and 6 comes to be inferior, i.e., connecting resistance therebetween becomes large and also the electric properties thereof are deteriorated. Further the stickiness or adhesiveness onto the solder or Sn plating is also deteriorated. As a result of this, solder wetability of the external electrodes 2 and 2 comes to be inferior, therefore mis-mounting easily occurs when mounting the multi layer ceramic electronic part(s) on the circuit board.

SUMMARY OF THE INVENTION

[0013] An object, according to the present invention, for dissolving the problem in the conventional art mentioned above, is to provide a multi layer ceramic electronic parts, wherein such the cracks in the laminated hardly occur due to the heart-shock accompanying with change of temperature under the conditions of when being soldered and of use thereafter, and further the adhesiveness between the external and internal electrodes and the adhesiveness of solder onto the external electrode are superior, as well, thereby also being superior in soldering property with the external electrodes.

[0014] According to the present invention, for achieving the above-mentioned object, pillar-like ceramic portions 22 extending in a direction of thickness of a conductor film 21 are scattered in the conductor films 21 of the external electrodes 2 and 2. Each the ceramic portion contains a material common to the ceramic material forming the ceramic layers 7 of the laminated body 3, therefore it has a strong bonding power onto the ceramic layers 7 of the laminated body 3. On the other hand, the conductor layer 21 has a strong bonding power onto the internal electrodes 5 and 6 of the laminated body 3, and shows a good adhesiveness onto a plating film 24 on the surface thereof. Complementing such the conductor films 21 and the ceramic portions 22 scattered therein each other in the characteristics thereof, it is possible to ensure the bonding power of the external electrodes 2 and 2 at the end portion and the adhesiveness with the plating thereof, and also to prevent from occurring the cracks within the laminated body 3.

[0015] Namely, according to the present invention, there is provided a multi layer ceramic electronic parts, comprising:

[0016] a laminated body 3 in which a ceramic layer 7 and internal electrodes 5 and 6 are laminated one another; and

[0017] external electrodes 2 and 2 being provided at end portions of the laminated body 3, in which the internal electrodes 5 and 6 opposing to each other reach to either one of at least a pair of edges of the ceramic layer 7, thereby leading out the internal electrodes 5 and 6 opposing to each other to either one of end surfaces of the laminated body 3, and connecting the internal electrodes 5 and 6 led out to the end surfaces of the laminated body 3 with the external electrodes 2 and 2, respectively. Wherein pillar-like ceramic portions 22, being continuous in a direction of thickness of a conductor film 21 forming the external electrodes 2 and 2, are scattered in the conductor film 21.

[0018] The ceramic portions 22, since containing the material common with the ceramic material forming the ceramic layers 7 of the laminated body 3, have strong bonding power onto the ceramic layers 7 of the laminated body 3. Those ceramic portions 22 are formed so that they are continuous from an inner surface of the conductor film 21 of the external electrodes 2 and 2 where it is in closely contact with a surface of the laminated body 3 up to an outer surface thereof.

[0019] According to the present invention, the conductor film 21 of the external electrodes 2 and 2 is made of at least one metal selected from a group of Ni, Cu, Ag, Pd and Ag—Pd, and the external electrodes 2 and 2 are baked at same time of baking of the laminated body 3.

[0020] In such the multi layer ceramic electronic parts, since the ceramic portions 22, containing the so-called the common material therein, shows a good adhesiveness onto the ceramic layers 7 at the end portions of the laminated body 3, the adhesiveness of the external electrodes 2 and 2 can be maintained at the end portions of the laminated body 3. However, the ceramic portions 22 are in a pillar-like shape and are in the condition of being scattered in the external electrodes 2 and 2, the external electrodes 2 and 2 do not adhere to the ceramic layers 7 at the end portions of the laminated body 3, but rather adhere in a spot-like manner. Therefore, when a change occurs in temperature, the thermal stress occurring within the laminated body 3 is released or mitigated, accompanying the thermal expansion and/or shrinkage of the conductor films 21 of the external electrodes 2 and 2, thereby hardly bringing about the cracks within the laminated body 3.

[0021] On the other hand, the conductor films 21 being formed to enclose around the ceramic portions 22 shows a good adhesiveness with the internal electrodes 5 and 6 at the end surfaces of the laminated body. With this, the contact resistance between the external electrodes 2 and 2 and the internal electrodes 5 and 6 comes to be small, and at the same time, it is also difficult to cause an exfoliation of the conductor films 21 from the end surfaces of the laminated body 3, in particular, from the internal electrodes 5 and 6.

[0022] Further, by baking the external electrodes 2 and 2 at the same time when the laminated body 3 is baked, i.e., the baking of the so-called the common material, which is contained in the conductor paste for forming the conductor films 21 of the external electrodes 2 and 2, in other words, the baking of the material for forming the ceramic portions 22 of the external electrodes 2 and 2 is performed at the same time of baking of the laminated body 3, therefore the ceramic portions 22 of the external electrodes 2 and 2 and the ceramic layers 7 of the laminated body 3 are baked as one body to obtain a strong adhesiveness therebetween.

[0023] In addition, the adhesiveness of the plating on surface sides of the external electrodes 2 and 2 is also good, therefore forming a fine plating film thereon, thereby obtaining a good adhesiveness with the solder.

[0024] As is mentioned previously, with the multi layer ceramic electronic parts, according to the present invention, not only the adhesiveness between the external electrodes 2 and 2 and the internal electrodes 5 and 6 at the end surfaces of the laminated body 3, but also the adhesiveness between the external electrodes 2 and 2 and the ceramic layers 7 comes to be good. Also, the adhesiveness of the plating of solder or Sn is good upon the surfaces of the external electrodes 2 and 2. As a result of this, the wetability with solder of the external electrodes 2 and 2 is also good, thereby obtaining a high strength in soldering when the component is mounted.

[0025] Furthermore, the thermal stress hardly occur accompanying with the change of temperature, therefore the cracks do not occur within the ceramic layers 7.

[0026] Such the multi layer ceramic electronic parts, according to the present invention, is obtained by the following steps of:

[0027] preparing the laminated body 3 being unbaked;

[0028] applying and drying a conductor paste, into which is added a material common with a ceramic forming the ceramic layers 7 of the laminated body 3 with a conductor powder, on the edge portions of the unbaked laminated body 3;

[0029] forming the external electrodes 2 and 2 so that they are conducted with the internal electrodes 5 and 6 at the end surfaces of the laminated body 3, by baking the laminated body 3; and

[0030] completing the multi layer ceramic electronic parts.

[0031] As is mentioned previously, when baking the conductor paste containing the material common with the ceramic material for forming the ceramic layers 7 of the laminated body 3, due to bad wetability of the conductor powder with the ceramic particles when being melt within the conductor paste, the ceramic particles come together by themselves to form the ceramic portions 22 mentioned above, therefore they are scattered in the conductor films 21 of the external electrodes 2 and 2.

BRIEF DESCRIPTION OF DRAWINGS

[0032] FIG. 1 is a perspective view of a multi layer ceramic electronic parts according to the present invention, a portion o which is cut out;

[0033] FIG. 2 is an enlarged cross-section view of a principle portion, in particular showing a portion A in the FIG. 1 of the above multi layer ceramic electronic parts;

[0034] FIG. 3 is an exploded view for showing the layers of a laminated body, in an example of the above multi layer ceramic electronic parts; and

[0035] FIG. 4 is an exploded view for showing a condition of laminating of a ceramic green sheets for manufacturing the multi layer ceramic electronic parts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Hereinafter, detailed and concrete explanation of the embodiments according to the present invention will be given by referring to attached drawings.

[0037] Explanation will be given on a laminated ceramic capacitor, as an example of the a multi layer ceramic electronic parts, and on a method for manufacturing thereof.

[0038] First of all, a powder of dielectric ceramic material, such as barium titanate, for example, is dispersed into an organic binder, such as acryl or the like, being dissolved into a solvent, such as ethanol, etc., thereby to prepare ceramic slurry. This ceramic slurry is pasted or applied thinly, on a base film made from a polyethylene terephthalate film or the like, with a constant thickness, and is dried, thereby producing a film-like ceramic green sheet. After that, this ceramic green sheet is cut out into an appropriate size.

[0039] Next, as shown in FIG. 4, on the cut ceramic green sheets 1a and 1b, two (2) kinds of internal electrode patterns 2a and 2b are printed, respectively, with using a conductor paste. For example, the conductor paste is obtained by adding into 100 weight % of a one kind of conductor power selected from Ni, Cu, Ag, Pd, Ag—Pd, 3-12 weight % of a binder selected from ethyl cellulose, acryl, polyester, etc., and 80-120 weight % of a solvent selected from butyl carbitol, butyl carbitol acetate, terpineol, ethylcellosolve, hydrocarbon, etc., and they are mixed and dispersed equally, to be applied.

[0040] The ceramic green sheets 1a and 1b, on which such the internal electrode patterns 2a and 2b are printed, are piled up one another, as shown in the FIG. 4, and on both sides (i.e., an upper side and a lower side) thereof are further piled up with the ceramic green sheets 1 and 1, on which no such the internal electrode pattern 2a or 2b is printed, i.e., dummy sheets, and then they are suppressed to be obtained as the laminated body. Further, this laminated body is cut in vertical and horizontal directions, to be separated into each of the chip-like laminated body. In such the laminated body 3, the internal electrodes 5 and 6, opposing to each other through the ceramic layer 7, are led out to both end surfaces of the laminated body 3, alternatively.

[0041] On the other hand, the paste is prepared for forming the external electrodes 2 and 2. For this conductor paste is used one which contains a one kind of conductor powder, being selected from Ni, Cu, Ag, Pd, Ag—Pd, etc., in the same manner as when applying or printing the electrode patterns 2a and 2b. However, into the conductor paste is added a so-called a common material, i.e., a material common with the ceramic which forms the ceramic layers 7 of the laminated body 3.

[0042] For example, in a case where the conductor material contained in the conductor paste is Ni, the conductor paste is prepared by adding into 100 weight % of Ni powder, 3-12 weight % of ethyl cellulose as the binder, 80-120 weight % of the solvent, and 3-40 weight % of barium titanate powder as the so-called common material. If the conductor material contained in the conductor paste is Cu, Ag, Pd or Ag—Pd, the conductor paste is prepared in the same manner.

[0043] Next, upon both end surfaces of the unbaked laminate body, on which the internal electrode patterns 2a and 2b are led out, and also covering a portion of the side surfaces of the laminated body being continuous with those both end surfaces, the conductor paste mentioned above is applied or painted, and is dried. Thereafter, by baking those laminated bodies, the laminated bodies are baked, and at the same time are also baked the conductor paste forming the internal electrode patterns 2a and 2b and the conductor paste applied on the end portions of the laminated body. With this, there can be obtained the baked laminated body 3 having the layer structure as shown in the FIG. 3, and having the external electrodes 2 and 2 at the end portions thereof.

[0044] As shown in the FIG. 3, the laminated body 3 are formed by laminating the ceramic layers 7, 7 . . . of dielectric material, each having the internal electrode 5 or 6, and further are laminated plural layers of the ceramic layers 7, 7 . . . on which no such the internal electrodes 5 and 6 is formed, on both sides (i.e., upper or lower sides thereof), respectively. In such the laminated body 3, the internal electrodes 5 and 6, opposing to each other through the ceramic layer 7, are led out one another on both end surfaces thereof. And, as shown in the FIG. 1, by baking the conductor paste on the both end surfaces of the laminated body 3 where the internal electrodes 5 and 6 are led out one another, the formed external electrodes 2 and 2 are conducted to the internal electrodes 5 and 6.

[0045] In the manner mentioned above, when baking the conductor paste containing the material common with the ceramic material forming the ceramic layers 7 of the laminated body 3, first the conductor powder within the conductor paste is melt, thereafter it begins to be sintered and shrinks. Namely, when it comes to be the temperature of starting the sintering of the metal powder of the conductor paste, first the metal melting is condensed and begins to shrink. When the metal is in the condition of melting, the ceramic particles have bad wetabity with the melting metal, therefore the melting metal and the ceramic particles are in the condition that they can be easily separated from each other. When the melting metal stars the condensation under this condition, the common material scattered therein is pushed out. The common material which is pushed out comes together with the particles adjacent to each other when it comes up to the temperature of starting the sintering of the ceramic, therefore it is formed in a pillar-like shape like stitching between the metal particles, and is extended to form the ceramic portion 22. The ceramic portion 22 formed in this manner, one of which reaches to a surface portion of a lower ceramic layer 7 of the external electrodes 2 and 2 to be connected therewith, and the other of which is extended to the surfaces of the external electrodes 2 and 2. As a result of this, it comes to be the pillar-like ceramic portion extending from the surface of the laminated body 3 to the surfaces of the external electrodes 2 and 2. This ceramic portion 22 is scattered in the conductor film 21.

[0046] FIG. 2 shows the cross-section of the external electrode 2 which is formed in this manner, in diagrammatic, in particular, the FIG. 2 (a) shows an enlarged cross-section view of a portion corresponding to the portion A in the FIG. 1, and the FIG. 2 (b) shows a view of the surface of the external electrode 2 corresponding to the portion B in the FIG. 1. The condition of such the external electrode 2, i.e., the cross-section and the surface thereof can be observed by an optical microscope, and the FIGS. 2 (a) and (b) show the diagrammatic view thereof.

[0047] As is shown in the FIG. 2, the external electrodes 2 and 2 are formed by baking painted layers of the conductor paste on the end portions of the laminated body 3. And, in the conductor layer or film 21 of the external electrodes 2 and 2 are scattered the pillar-like ceramic portions 22, almost equally or uniformly in a plane direction, being continuous in a direction of the thickness.

[0048] In such the multi layer ceramic electronic parts, since the ceramic portions 22, containing the so-called the common material therein, show a good adhesiveness onto the ceramic layers 7 at the end portions of the laminated body 3, such the adhesiveness of the external electrodes 2 and 2 can be maintained at the end portions of the laminated body 3. However, the ceramic portions 22 are in a pillar-like shape and are in the condition of being scattered in the external electrodes 2 and 2, the external electrodes 2 and 2 do not adhere to the ceramic layers 7 at the end portions of the laminated body 3, but rather adhere in a spot-like manner. Therefore, when change occurs in temperature, the thermal stress occurring within the laminated body 3 is released or mitigated accompanying the thermal expansion and/or shrinkage of the conductor layers 21 of the external electrodes 2 and 2, thereby hardly causing the cracks within the laminated body 3.

[0049] Further, by baking the external electrodes 2 and 2 at the same time when the laminated body 3 is baked, i.e., the baking of the so-called the common material, which is contained in the conductor paste for forming the conductor layers or films 21 of the external electrodes 2 and 2, in other words, the baking of the material for forming the ceramic portions 22 of the external electrodes 2 and 2 is performed at the same time of the baking of the laminated body 3, therefore the ceramic portions 22 of the external electrodes 2 and 2 and the ceramic layers 7 of the laminated body 3 are baked in a one body.

[0050] On the conductor layer or film 21 formed in the manner mentioned above, the plating of Sn or solder is treated, and the external electrodes 2 and 2 are formed. Thereby, the multi layer ceramic electronic parts is completed. The portion which is indicated by an imaginary two-dot chain line in the FIG. 2 (a) shows the solder layer.

[0051] Though the explanation was given mainly on the laminated ceramic capacitor as one example of the multi layer ceramic electronic parts in the embodiment mentioned above, however the present invention relating to the multi layer ceramic electronic parts can be also applied to, for example, a laminated ceramic inductance, a laminated ceramic LC composite part, a ceramic multi-layer wiring print board, etc.

Claims

1. A multi layer ceramic electronic parts, comprising: a laminated body in which a ceramic layer and internal electrodes and are laminated one another; and external electrodes and being provided at end portions of the laminated body, in which the internal electrodes and opposing to each other reach to either one of at least a pair of edges of the ceramic layer, thereby leading out the internal electrodes and opposing to each other to either one of end surfaces of the laminated body, and connecting the internal electrodes and led out to the end surfaces of the laminated body to the external electrodes and, respectively, wherein pillar-like ceramic portions, being continuous in a direction of thickness of a conductor film forming the external electrodes and, are scattered in the conductor film.

2. A multi layer ceramic electronic parts as defined in the claim 1, wherein the ceramic portions contain a material common with ceramic material which forms the ceramic layer of the laminated body.

3. A multi layer ceramic electronic parts as defined in the claim 1 or 2, wherein the ceramic portions of the external electrodes and are so formed that they are continuous from an inner surface of the conductor film of the external electrodes and where it is closely contact with a surface of the laminated body up to a surface thereof.

4. A multi layer ceramic electronic parts as defined in any one of the claims 1 to 3, wherein the conductor film of each of the external electrodes and is made of at least one metal selected from a group consisting of Ni, Cu, Ag, Pd and Ag—Pd.

5. A multi layer ceramic electronic parts as defined in any one of the claims 1 to 4, wherein the external electrodes and are baked at same time of baking the laminated body.

6. A method for manufacturing a multi layer ceramic electronic parts, comprising: a laminated body in which a ceramic layer and internal electrodes and are laminated one another; and external electrodes and being provided at end portions of the laminated body, in which the internal electrodes and opposing to each other reach to either one of at least a pair of edges of the ceramic layer, thereby leading out the internal electrodes and opposing to each other to either one of end surfaces of the laminated body, and connecting the internal electrodes and led out to the end surfaces of the laminated body to the external electrodes and, respectively, wherein comprising following steps of: preparing the laminated body being unbaked; applying and drying a conductor paste, into which is added a material common with a ceramic forming the ceramic layers of the laminated body with a conductor powder, on the edge portions of the unbaked laminated body; forming the external electrodes and so that they are conducted with the internal electrodes and at the end surfaces of the laminated body, by baking the laminated body; and completing the multi layer ceramic electronic parts.

7. (New) A method for manufacturing a multi-layer ceramic electronic part, said multi-layer ceramic electronic part comprising a laminated body in which a ceramic layer and internal electrodes are laminated on one another, external electrodes provided at end portions of the laminated body, the internal electrodes opposing each other and reaching to one of at least a pair of edges of the ceramic layer, thereby leading out the internal electrodes to an end surface of the laminated body and connecting the internal electrodes to the external electrodes, and pillar-like ceramic portions which are continuous in a direction of thickness of a conductor film forming the external electrodes and scattered in the conductor film, said method comprising the steps of: preparing an unbaked laminated body comprising a ceramic layer and internal electrodes laminated on one another; applying and drying a conductor paste, into which is added a material common with a ceramic forming the ceramic layer of the laminated body, on edge portions of the unbaked laminated body; forming external electrodes in contact with the internal electrodes at end surfaces of the laminated body; baking the laminated body; and completing the multi-layer ceramic electronic part.

8. (New) The method of claim 7, additionally comprising the step of providing pillar-like ceramic portions which are scattered in a conductor film forming the external electrodes and continuous in a direction of thickness of the conductor film.

9. (New) The method of claim 7, additionally comprising the step of forming the ceramic portions of the external electrodes so that they are continuous from an inner surface of the conductor film of the external electrodes, where it closely contacts with a surface of the laminated body, up to an outer surface thereof.

10. (New) The method of claim 7, additionally comprising the step of forming the conductor film of at least one metal selected from the group consisting of Ni, Cu, Ag, Pd and an Ag—Pd alloy.