JP2002100529A - Ceramic laminated electronic component and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic laminated electronic component having no disadvantage due to defective plating or the like and a method of manufacturing the same. SOLUTION: In the ceramic laminated electronic component and method of manufacturing the same, an exposed electrode is coated with an organic film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multilayer ceramic electronic component and a method of manufacturing the same, and more particularly, to a multilayer ceramic electronic component having an exposed electrode and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, in order to protect a fired electrode from deterioration factors due to oxidation or the like, and to maintain good bonding with solder or the like, a metal film by plating or the like has been formed on the electrode surface. However, in recent years, there has been a great demand for smaller and more sophisticated electronic components, and the exposed electrodes of the electronic components themselves have become denser and more delicate. The situation is likely to occur.

[0003] Principal types of plating include Ni / Au, Ni / Sn, and Ni / solder, regardless of whether they are electrolytic or non-electrolytic. An example in which a Cu electrode is covered with Ni / Au plating has the following features. If the Cu electrode is left unexposed, deterioration of the electrode due to oxidation or the like occurs, and the solder wettability deteriorates. Au serves as an antioxidant film and has good solder wettability. However, due to heating during the assembly process after plating, Au becomes Cu
It has the property of diffusing into the electrode. By sandwiching Ni between the Cu electrode and Au, Au
Has the effect of preventing the diffusion of Cu into the Cu electrode. In order for Ni to exhibit the effect of preventing diffusion of Au, the film thickness of Ni needs to be about 3 μm or more. Since Ni alone has poor wettability to solder, Au plating is required on the surface.

Conventionally, in an electroless Ni / Au plating process or the like, a catalyst is applied to the exposed electrode, and the catalyst is replaced with Ni to deposit Ni only on the exposed electrode surface. Au was then precipitated by substituting Ni for Au.

[0005]

However, this process has the following disadvantages. In the case of electroless plating, poor plating occurs due to poor adhesion and replacement of the catalyst. Discoloration failure occurs in the deposited film due to variations in the crystallinity of the deposited plating metal and adhesion of foreign matter. Uneven printing of the electrode or shavings of the electrode due to dicing or the like on the substrate surface cause abnormal deposition of plating. In addition, Ni plating or the like requires a film thickness of about 3 μm or more in order to make the stopper effect work effectively. The fine powder is joined by plating, which causes a short path. Since the metal deposited by plating grows isotropically, if the line space is reduced, the plating straddles adjacent lines, forming a short path. When a metal film is deposited on the electrode by plating, the effect of the metal film on the electrode surface, such as residual stress,
The electrode bonding strength decreases. By-products during plating deposition and the plating solution itself are taken into the film, which prevents uniform plating film deposition. Since the method is a method of precipitating heavy metals, there is a possibility that the surrounding environment may be adversely affected.

SUMMARY OF THE INVENTION Therefore, a main object of the present invention is to provide a ceramic laminated electronic component free from the above-mentioned disadvantages and a method of manufacturing the same.

[0007]

SUMMARY OF THE INVENTION The present invention is a multilayer ceramic electronic component characterized in that the exposed electrode is covered with an organic film. Further, the present invention is a method for manufacturing a ceramic laminated electronic component, comprising a step of dissolving and removing an oxide present on a surface of an exposed electrode, and then forming an organic film on the surface of the exposed electrode. In the present invention, the organic coating preferably has a rust-preventive effect. In the present invention, the organic coating is preferably insulating. Further, in the present invention, the organic film is formed of an azole compound such as imidazole, benzimidazole, benzotriazole, tolyltriazole and derivatives thereof (alkyl group such as methyl group and ethyl group, carboxyl group, amino group, hydroxyl group, etc. Is preferred as a component of the azole compound. Further, in the present invention, it is preferable that the exposed electrode contains a baked metal as a main component. Further, in the present invention,
The exposed electrode preferably contains at least one of Cu, Ag, Ni, Sn, and Fe as a component. Further, in the present invention, it is preferable that all electrodes exposed on the surface of the ceramic multilayer electronic component are exposed electrodes.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention with reference to the accompanying drawings.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a ceramic laminated electronic component having electrodes exposed to the outside is prepared. The exposed electrode is formed of, for example, a fired metal containing at least one of Cu, Ag, Ni, Sn, and Fe as a component. Next, the exposed electrode surface is treated with an aqueous solution etchant such as a ferric chloride, ferric chloride, sulfites, alkali etchant, ammonium peroxylate, sodium peroxylate, or a mixture of sulfuric acid and hydrogen peroxide. Etch. In order to apply the etchant to the exposed electrode surface, the ceramic substrate may be dipped in the etchant, or the etchant may be applied by spraying or a roll coater. By this etching, an oxide layer and organic contaminants on the electrode surface can be removed.

Immediately after performing the etching treatment, it is preferable to wash in an undried state with ion-exchanged water heated to about 40 ° C. to 70 ° C. for 5 seconds to 60 seconds, and then to wash with ion-exchanged water at room temperature. In order to simplify the process, washing may be performed immediately after etching with ion-exchanged water at normal temperature. The ion-exchanged water may be distilled water or other water having relatively little dissolved matter. In addition, the cleaning step using heated ion-exchanged water is intended to oxidize the electrode surface, and thus has a poor cleaning effect. However, even if the cleaning step is performed using warm air, heated steam, or heated alcohols. Good.

Draining and drying are performed to prevent the etchant and cleaning solution remaining on the electrode surface from being carried into the next step. This is because when the etchant is brought into the organic film solution in the next step, the solution shows a decomposition reaction and a stable organic film cannot be formed. In this step, cold-air drying, hot-air drying, and dehydration with a water-absorbing material may be used. However, it is effective to perform water drying after removing water with a gas having a low dew point.

An electrode is immersed in a solution of an organic coating to deposit an organic coating on the surface of the electrode. If necessary, the electrode is rocked or the liquid is stirred during immersion. The method of depositing the organic film is not limited to the dipping method, and the organic film may be applied by spraying a solution by spraying or by a roll coater. Solutions for forming an organic film include azole compounds such as imidazole, benzimidazole, benzotriazole, and tolyltriazole and derivatives thereof (alkyl groups such as methyl group and ethyl group, carboxyl group, amino group, hydroxyl group, etc. Is used as a component of the azole compound.

After the application, it is washed again with a washing liquid such as ion-exchanged water and dried. In this step, cold-air drying, hot-air drying, and dehydration with a water-absorbing material may be performed, but it is preferable to drain the water with a gas having a low outdoor temperature. After that, heat drying is effective because the organic coating is stabilized.

[0014]

Embodiment 1 FIG. 1A is a front view of a test piece of a ceramic laminated electronic component used in Embodiment 1, and FIG. 1B is a bottom view thereof. In FIG. 1, a1 = 0.35 ± 0.
20 mm, a2 = 0.50 ± 0.10 mm, h1 = 0.
70 ± 0.20 mm and b1 = 0.35 ± 0.20 mm.

A test piece of a ceramic laminated electronic component having a copper electrode having the shape shown in FIG. 1 was immersed in TH-1 manufactured by Shikoku Chemicals Co., Ltd. diluted 4 times for 30 seconds and etched. Thereafter, the substrate was washed with ion-exchanged water heated to 55 ° C. for 10 seconds. Next, the substrate is washed with ion exchanged water at 25 ° C. for 30 seconds, washed thoroughly with a washing machine, drained with dry air, and dried in an air oven at 100 ° C. for 30 seconds.
Heat drying was performed for 2 seconds. Next, the exposed electrode was covered with an organic film by immersing in Tough Ace (registered trademark) F2 manufactured by Shikoku Chemicals Co., Ltd. heated to 40 ° C. for 5 minutes while rocking. This organic coating has insulating properties and rust prevention properties. Next, the substrate was washed with ion exchanged water at 25 ° C. for 30 seconds, washed thoroughly with a washing machine, drained with dry air, and thermally dried in an air oven at 100 ° C. for 30 seconds.

The test piece thus obtained was subjected to JI
According to the S standard, the solder wettability was measured by the solder ball method. The measuring method is as follows. The above test piece 10
After preparing a piece and applying flux to the electrode of each test piece, while maintaining the angle of the test piece electrode at 45 ° with the vertical direction, the surface of the melt was heated at 235 ° C with a clean and shiny surface. The ball was immersed in ball solder (60% by weight tin / 40% by weight lead eutectic solder) at a rate of 0.4 mm / sec to a depth of 0.1 mm. After 5 seconds after the contact between the electrode and the small ball solder, it was lifted up, and the solder wettability was confirmed with a 10 × microscope, and the solder covering 99% or more of the electrode surface was regarded as good (corresponding standard: International Standard IEC68-2-54
− (1985), Japanese Industrial Standard JIS C0053
(1990), Electronic Equipment Manufacturers Association Standard EIAJ ET-
7401 (1996)). Table 1 shows the measurement results.

As Comparative Example 1, Ni: 5 was formed on the exposed electrode of the test piece having the shape shown in FIG.
μm / Au: A metal coating having a thickness of 0.4 μm was provided, and the results of a test performed in the same manner as in Example 1 are shown in Table 1. Further, as Comparative Example 2, a completely untreated test piece having the shape shown in FIG.
The results are shown in Table 1.

[0018]

[Table 1]

From the results shown in Table 1, it can be seen that this example has the same solder wettability as Comparative Example 1 which has been subjected to metal plating. Further, in Comparative Example 2 in which the treatment after firing was not performed, no solder wettability was exhibited, indicating that the organic coating according to the present example effectively acts on solder wettability.

[0020]

Second Embodiment FIG. 2 is a bottom view showing a test piece of a ceramic laminated electronic component used in a second embodiment. This ceramic laminated electronic component has a square copper electrode of 0.7 mm
A plurality is arranged at a pitch of 7 mm along four sides of the bottom surface. This test piece was immersed in TH-1 manufactured by Shikoku Chemical Industry Co., Ltd. diluted 4 times for 30 seconds and etched. Thereafter, the substrate was washed with ion-exchanged water heated to 55 ° C. for 10 seconds. Next, the substrate was washed with ion-exchanged water at 25 ° C. for 30 seconds, and thoroughly washed with a washing machine. Thereafter, draining was performed with dry air, and heat drying was performed in an air oven at 100 ° C. for 30 seconds. Next, to Tough Ace (registered trademark) F2 manufactured by Shikoku Chemicals Co., Ltd.
The exposed electrode was covered with an organic film by immersing for 5 minutes while rocking. Next, after washing with ion exchanged water at 25 ° C. for 30 seconds, the washing was thoroughly performed with a washing machine.
Drained with dry air, and heat-dried in an air oven at 100 ° C. for 30 seconds. Then, it passed twice through a high-temperature reflow furnace (peak temperature: 260 ° C., 250 ° C. or more: 40 seconds).

The test piece thus obtained was subjected to JI
According to the S standard, the solder wettability was measured by the solder ball method. The measuring method is as follows. The above test piece 10
After preparing flux pieces and applying flux to the electrodes of each test piece, the molten test piece solder was heated at 235 ° C. (60% by weight tin / 40 wt. (Weight% lead eutectic solder)
The ten test target electrodes on the lower end side of the test piece were immersed at the speed of c. After raising the electrode 2 ± 0.5 seconds after the contact between the electrode and the small ball solder, the wettability of the solder was confirmed by a microscope of 10 ×, and the solder covered with 95% or more of the electrode surface was regarded as a good product ( Corresponding standard: International standard IEC 68-2
-20- (1979), Japanese Industrial Standard JIS C00
50 (1985)). Table 2 shows the measurement results.

Further, as Comparative Example 3, the washing with ion-exchanged water heated to 55 ° C. in Example 2 was not performed.
Table 2 shows the results of a test performed in the same manner as in Example 2 for the case of cleaning with ion-exchanged water at 25 ° C. after etching with H-1. The number of NGs in Table 2 indicates the number of NG electrodes in 100 electrodes (10 test pieces).

[0023]

[Table 2]

The exposed electrode of the ceramic laminated electronic component has large irregularities due to paste particles and the like, and it is difficult to form an organic film uniformly in a normal processing step. Therefore, when a heat history due to reflow or the like is added, the electrode surface on which the organic film is not uniformly formed deteriorates, and the solder wettability deteriorates. However, immediately after forming a clean electrode surface by etching, a thin and uniform oxide film can be formed on the electrode surface by performing washing with heated ion-exchanged water. In addition, since azole compounds have the property of binding to monovalent ion components of metals,
The oxidized metal component has a higher attachment probability of the compound than the pure metal state. Therefore, by performing cleaning with heated ion-exchanged water on the exposed electrode after etching, the probability of forming an organic film can be increased even on an electrode surface having large irregularities. For these reasons, in Example 2 in which the exposed electrode immediately after etching was washed with heated ion-exchanged water, the solder wetness after reflow was smaller in Comparative Example 3 than in Comparative Example 3 in which the exposed electrode was not washed with heated ion-exchanged water. It is possible to significantly improve the performance.

[0025]

According to the organic coating of the present invention, the following effects can be obtained. It is possible to reduce the occurrence of abnormal discoloration and short paths while obtaining an electrode protection effect equivalent to that of a metal film. Since it is not deposited by a substitution reaction with a catalyst, there is no problem of poor deposition due to poor adhesion of the catalyst, poor reaction with the catalyst, and the like. An electrode protection effect can be achieved with a film thickness on the order of submicrons. Since the organic coating itself is insulative, a short bath between adjacent electrodes due to the coating does not occur. The organic coating does not exert a stress on the electrodes to lower the electrode bonding strength. Since the organic film is deposited by adsorption on the electrode surface,
No by-products such as electroless plating are generated. Therefore, the amount of foreign matter taken into the film is small. According to the organic film, it is possible to form a transparent film, and according to the transparent film, the color tone of the electrode does not change due to the protective film forming step. Since the main constituent elements of the organic film are C, N, and H, they have less adverse effects on the surrounding environment than the plating process using heavy metals.

[Brief description of the drawings]

FIG. 1A is a front view of a test piece of a ceramic laminated electronic component used in Example 1, and FIG. 1B is a bottom view thereof.

FIG. 2 is a bottom view showing a test piece of the ceramic laminated electronic component used in Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ceramic laminated electronic component 12 Exposed electrode

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shintaro Karaki 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto F-term in Murata Manufacturing Co., Ltd. (Reference) 5E001 AA00 AB03 AC00 AD00 AE00 AF02 AH01 AH07 AJ03 AJ04 5E082 AA01 AB03 BC19 FF05 FG06 FG26 FG54 GG10 GG11 GG26 GG28 HH26 HH44 HH51

Claims (12)

[Claims] 1. A ceramic laminated electronic component, wherein an exposed electrode is covered with an organic film. 2. The multilayer ceramic electronic component according to claim 1, wherein the organic coating has a rust-preventive effect. 3. The organic coating according to claim 1, wherein said organic coating is insulating.
Or the ceramic laminated electronic component according to claim 2. 4. The organic film is formed of an azole compound such as imidazole, benzimidazole, benzotriazole, tolyltriazole and derivatives thereof (such as an alkyl group such as a methyl group or an ethyl group, a carboxyl group, an amino group, a hydroxyl group, etc.). The ceramic laminated electronic component according to any one of claims 1 to 3, wherein the component comprises a compound group in which is bonded to a benzene ring in the azole compound. 5. The multilayer ceramic electronic component according to claim 1, wherein the exposed electrode has a fired metal as a main component. 6. The exposed electrode is made of Cu, Ag, Ni, S
The multilayer ceramic electronic component according to claim 1, wherein at least one of n and Fe is contained as a component. 7. A method for manufacturing a ceramic multilayer electronic component, comprising a step of dissolving and removing an oxide present on a surface of an exposed electrode, and then forming an organic film on the surface of the exposed electrode. 8. The method according to claim 7, wherein the organic coating has a rust-preventing effect. 9. The organic coating according to claim 7, wherein the organic coating is insulating.
A method for manufacturing a ceramic multilayer electronic component according to claim 8. 10. The organic film is formed of an azole compound such as imidazole, benzimidazole, benzotriazole, tolyltriazole and derivatives thereof (such as an alkyl group such as a methyl group or an ethyl group, a carboxyl group, an amino group, a hydroxyl group, etc.). 10. The method for producing a ceramic laminated electronic component according to claim 7, wherein the component comprises a compound group in which is bonded to a benzene ring in the azole compound. 11. The method for manufacturing a ceramic multilayer electronic component according to claim 7, wherein said exposed electrode mainly comprises a fired metal. 12. The method according to claim 11, wherein the exposed electrodes are Cu, Ag, Ni, S
The method for producing a ceramic multilayer electronic component according to claim 7, wherein at least one of n and Fe is contained in a component.