JP2003253489A - Method of plating electronic component and electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid peeling of electrodes or failures in electric connections and to obtain high quality electronic components having excellent reliability. <P>SOLUTION: When a nickel coating 7 and a tin coating 8 are formed on an article to be plated, which article is a ceramic base body 3 having electrodes 6 on its surface, the nickel coating 7 and the tin coating 8 are successively formed on the article by subjecting the article to plating treatment while impressing a potential of -0.7 V versus the standard hydrogen electrode potential or an electrochemically nobler potential than -0.7 V to the article to be treated. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for plating electronic parts and electronic parts, and more particularly to a method for plating electronic parts in which electrodes are formed on the surface of a ceramic body, and manufacturing using the plating method. Related electronic components.

[0002]

2. Description of the Related Art Electronic components having electrodes formed on the surface of a ceramic body have conventionally been nickel-plated or tin-plated to improve heat resistance and solder wettability of the electrodes. ing.

That is, in this type of electronic component, for example, an anode plate made of plated metal is used as an anode, a barrel side having a cathode plate and an object to be plated is used as a cathode, and the barrel is rotated and rocked. While doing so, an electric current is applied between the anode and the cathode to apply a potential, thereby depositing a metal on the electrode of the object to be plated to form a plating film.

The conventional plating treatment is carried out by controlling the current value flowing between the anode and the cathode in the plating bath and the plating time, and from the viewpoint of improving the productivity, the anode and the cathode are treated together. A large amount of current is applied to the plating process in a short time. That is,
A potential that is electrochemically deviated to the base metal as much as possible with respect to a plating metal such as Ni or Sn is applied to the object to be plated for plating.

[0005]

However, in the conventional plating method, as described above, the potential which is electrochemically shifted to the base metal as electrochemically as possible with respect to the plated metal so as to perform the plating treatment in a short time is applied. Since the ceramic element body near the electrode, that is, the metal oxide, is reduced by the potential applied during plating, the structure of the ceramic element body is chemically destroyed. There is a problem that the adhesion strength to the element body is lowered, the electrode may be peeled off from the ceramic element body, or conduction failure may be caused. That is, in order for the plating reaction to proceed, it is necessary to apply an electrochemically base potential to the object to be plated, which is lower than the equilibrium electrode potential of the plating metal. When applied to the electrode of the plated product, the ceramic body in the vicinity of the electrode maintains the state of the metal oxide, but as the applied potential shifts to the base, the surface layer surface of the metal oxide is ionized and further becomes a metal. The state changes. That is, as the potential applied to the object to be plated during plating becomes more base, the metal oxide is more easily reductively decomposed, the structural destruction of the ceramic body progresses, and the adhesion strength of the electrode to the ceramic body decreases. Therefore, in the case of the thin film electrode, there is a problem that peeling of the electrode from the ceramic body and poor conduction are likely to occur, and also in the case of the thick film electrode, poor conduction is likely to occur.

The present invention has been made in view of the above problems, and it is an electronic component capable of obtaining a high-quality electronic component having excellent reliability by avoiding peeling of electrodes and defective conduction. An object of the present invention is to provide a plating method and an electronic component manufactured by using the plating method.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted diligent research in order to prevent the adhesion strength of the electrode to the ceramic body from being deteriorated even if plating treatment is performed. It was found that the plating material changes depending on the applied potential to the electrode. That is, in order to proceed the plating reaction, it is necessary to apply an electrochemically base potential to the object to be plated as compared with the equilibrium electrode potential of the plating metal as described above, but a potential that is excessively base shifted. It was found that the adhesion strength was reduced by applying. Then, the present inventors have found that the applied potential to the object to be plated is − based on the standard hydrogen electrode potential.
When it is electrochemically nobler than 0.7 V or −0.7 V, it is possible to avoid the reduction of the adhesion strength between the electrode and the ceramic body even if the plating object is plated. I got the knowledge.

The present invention has been made on the basis of such knowledge, and the plating method for electronic parts according to the present invention is
In a plating method for an electronic component, in which an object to be plated having an electrode formed on the surface of a ceramic body is subjected to a plating treatment to form a plating film on the surface of the electrode, a -0.7 V or-based on a standard hydrogen electrode potential is used. It is characterized in that the plating treatment is performed while applying an electrochemically nobler potential than 0.7 V to the object to be plated.

According to the above plating method, -0.7V (v
s. NHE (standard hydrogen electrode) or an electric potential nobler electrochemically than -0.7 V is applied to the object to be plated to form the plating film, so that the potential applied to the object to be plated is excessive. Without becoming base, it is possible to prevent the ceramic body from undergoing reductive decomposition and structural destruction, and to secure a desired adhesion strength.

In addition, the above-mentioned plating method exhibits excellent working effects particularly when nickel plating, tin plating, or tin alloy plating is performed.

That is, the method for plating an electronic component of the present invention is preferably characterized in that the plating film is made of nickel, tin, or a tin alloy.

The method for plating an electronic component of the present invention is
The plating solution in which the object to be plated is immersed has a hydrogen ion index p.
It is also preferable that H is 4 to 10, and the selection range of the substance species to be added to the plating solution is expanded by preparing the plating solution such that the hydrogen ion exponent pH is in such a range. It becomes possible.

Further, the method of plating an electronic component of the present invention is
It is also preferable that the electrode is a thin film electrode produced by performing a sputtering process, and the electrode is formed by applying and baking a conductive paste containing a conductive material and a glass component. It is also preferable that the thick film electrode is manufactured by the above method, which makes it possible to avoid problems such as electrode peeling and poor conduction in both the thin film electrode and the thick film electrode.

The electronic component according to the present invention is characterized by being manufactured by using the above-mentioned plating method,
Further, the ceramic body is characterized by being formed of one or more ceramic materials selected from a dielectric material, a piezoelectric material, an insulating material, or a semiconductor material.

According to the above configuration, -0.7V (vs.N
Since a plating film is formed by applying a noble potential electrochemically higher than HE (standard hydrogen electrode) or -0.7 V to the object to be plated, the thin film or thick film electrode is a ceramic body. It is possible to obtain various desired electronic components having excellent reliability without peeling off from the substrate or defective conduction.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view of a chip type ceramic oscillator as an embodiment of an electronic component according to the present invention.
2 is a sectional view taken along line AA of FIG.

The chip-type ceramic oscillator is composed of a pair of upper and lower dielectric substrates 1a and 1b containing a metal oxide such as barium titanate as a main component, and lead titanate sandwiched between the dielectric substrates 1a and 1b. And a piezoelectric substrate 2 mainly composed of a metal oxide such as titanic acid / lead zirconate (PZT). The dielectric substrate 1a, 1b and the piezoelectric substrate 2 form a ceramic body 3. There is.

Further, thin film electrodes 4 having a film thickness of 0.1 μm to 1.0 μm are formed on both side surfaces of the ceramic body 3 by a sputtering method, and are formed on the upper end portion of the dielectric substrate 1a and the lower end portion of the dielectric substrate 1b. The conductive paste is applied and fired to form thick film electrodes 5a and 5b having a film thickness of 1 μm to 50 μm. The thin film electrode 4 and the thick film electrodes 5a and 5b form the electrode portion 6.

The thickness of the electrode portion 6 is 0.5 μm on the surface.
The nickel coating 4 having a thickness of m to 5 μm is deposited, and the surface of the nickel coating 4 is coated with the tin coating 5 having a thickness of 1 μm to 10 μm.

The method of manufacturing the above chip-type ceramic oscillator will be described in detail below.

First, a piezoelectric substrate 2 made of lead titanate, PZT, or the like, which is polished so as to oscillate at a predetermined frequency.
Are sandwiched between a pair of dielectric substrates 1a and 1b such as barium titanate which are similarly polished, and they are bonded to each other with an adhesive to form a ceramic body 3.

Next, a predetermined conductive material is used as a target substance, and the side surface is subjected to predetermined masking and then subjected to a sputtering process to obtain a film thickness of 0.1 μm to 1.0 μm.
Thin film electrode 4 is formed.

The conductive material is not particularly limited, and for example, an alloy such as Ni-Cr, an alloy of Ni and Cu such as Monel metal, or a metal material such as Cu, Ti or Ag may be used. You can

Next, a conductive paste containing a glass component and an organic vehicle in a conductive material such as Cu or Ag is prepared, and the conductive paste is applied to the upper and lower ends of the ceramic body 3 and baked. Applied, film thickness 1 μm to 50 μm
The thick film electrodes 5a and 5b are formed.

In this way, the electrode portion 6 (thin film electrode 4
And the ceramic body 3 on which the thick film electrodes 5a, 5b) are formed is used as an object to be plated, and the object to be plated is subjected to nickel plating and tin plating by a wet electrolytic barrel method to form a nickel film 7 and a tin film 8. .

FIG. 3 is a schematic view of the wet electrolytic barrel plating apparatus used in this embodiment.

That is, the plating apparatus has an anode plate (anode) made of a plating metal (nickel or tin).
Barrel 13 in which 11 and cathode plate (cathode) 12 are inserted
Are immersed in an electrolytic bath 10 filled with a plating solution 9, and the anode plate 11 and the cathode plate 12 are electrically connected via a potentiostat 14. In addition, the electrolytic bath 10
Is KCl in which the reference electrode 16 is immersed in the KCl solution 15.
It is connected via a tank 17 and a salt bridge 18. The salt bridge 18 is filled with KCl and agar so that the plating solution 9 and the KCl solution 15 do not mix with each other.
The electrons are configured to move.

In the thus constructed plating apparatus, a predetermined number of objects to be plated are put in the barrel 13 and a current is passed between the anode plate 11 and the cathode plate 12, so that the potential applied to the objects to be plated is increased. The nickel plating film 7 and the tin plating film 8 are formed by performing electrolytic plating while controlling the potentiostat 14 via the reference electrode 16 so as to have a predetermined potential.

That is, when the nickel film 7 is formed, the electrolytic bath 10 is filled with the plating solution 9 containing a predetermined nickel ion source, and a current is passed between the anode plate 11 and the cathode plate 12 made of nickel. Then, electrolytic nickel plating is applied, whereby a nickel film 7 is formed on the surface of the electrode portion 6.

When the tin film 8 is formed, the electrolytic cell 10 is filled with the plating solution 9 containing a predetermined complexing agent and a tin ion source, and the tin anode plate 11 and cathode plate 12 are formed.
An electric current is passed between and to perform electrolytic tin plating, whereby a tin film 8 is formed on the surface of the nickel film 7.

In the present embodiment, the nickel film 7 and the tin film 8 are -0.7 V (vs. NHE;
The same applies to the following) or a potential that is electrochemically nobler than -0.7 V is applied to the object to be plated to perform the plating treatment.

That is, in order to cause a plating reaction to form a plating film, the plating metal Ni (-
0.25 V) or Sn (-0.14 V), which is electrochemically lower than the equilibrium electrode potential, needs to be applied to the object to be plated, but on the other hand, the applied potential is electrochemically lower than -0.7 V. When the plating treatment is performed by setting the potential to be a base, the metal oxide forming the ceramic body 3 is reductively decomposed and metal is deposited on the surface layer, so that the structure of the ceramic body 3 is chemically changed. There is a possibility that the electrodes may be destroyed and the adhesion strength between the electrode and the ceramic body after the plating treatment may be reduced, resulting in electrode peeling and poor conduction.

Therefore, in the present embodiment, the applied potential is set to −
The plating process is performed while controlling the potential to be electrochemically nobler than 0.7 V or -0.7 V.

The hydrogen ion exponent p of such a plating solution is also
H is 3 to 10 because the glass component in the ceramic body 3 is damaged in a strongly acidic solution or a strongly alkaline solution.
In view of increasing the degree of freedom of selection of the complexing agent, it is preferable to adjust it to 4 to 10.

The nickel plating solution and the tin plating solution may contain a metal ion source (nickel ion source or tin ion source) and a complexing agent, as well as a pH adjusting agent, a brightening agent and the like.

Here, various nickel salts can be used as the source of nickel ions, for example, nickel sulfate, nickel chloride, nickel sulfamate, nickel acetate, etc. can be used.

Various tin salts can also be used as the source of tin ions, for example, stannous sulfate, stannous acetate, stannous sulfamate, etc. can be used.

Further, a complexing agent is added to prevent nickel ions and tin ions from existing in the plating bath to form precipitates and to improve the stability of the bath. As the agent, citric acid, gluconic acid, acetic acid, glycine, pyrophosphoric acid, tartaric acid, boric acid, or salts containing these acids can be used.

The pH adjusting agent is appropriately added so that the pH value of the hydrogen ion index in the plating solution is in the range of 3 to 10, preferably 4 to 10. The pH adjusting agent is water. Various hydroxides such as sodium oxide and potassium hydroxide, or ammonium water can be used.

As the brightener, for example, a nonionic surfactant can be used.

As described above, in the present embodiment, the applied potential is controlled during plating, and -0.7V or a potential electrochemically nobler than -0.7V is applied to the object to be plated. It is possible to prevent the ceramic body from being reductively decomposed and chemically structurally destroyed. Therefore, a desired plating film (nickel film 7 and tin film 8) can be formed without lowering the adhesion strength between the electrode portion 6 and the ceramic body 3, and the chip does not cause electrode peeling or conduction failure. A ceramic resonator can be obtained.

The present invention is not limited to the above embodiment. Although tin plating is applied to the nickel film 7 using the tin plating solution in the above embodiment, tin alloy plating such as tin-lead, tin-silver, tin-copper, tin-bismuth, etc. is used instead of tin plating. May be applied.

Further, in the above embodiment, the piezoelectric substrate is sandwiched between the pair of upper and lower dielectric substrates. However, when an insulating substrate made of alumina or the like is used instead of the dielectric substrate, Needless to say, is also applicable.

In addition, although the thin film electrode is formed by the sputtering method in the above embodiment, the thin film electrode may be formed by the vacuum evaporation method.

Although the chip-type ceramic oscillator has been described as an example of the electronic component in the present embodiment, a chip-type ceramic filter having a thin film electrode formed by a sputtering method or a vapor deposition method, a chip-type EMI filter, and a chip 3 terminal. The same can be applied to a capacitor or a chip type thermistor formed of a semiconductor ceramic, and a chip type multilayer capacitor having a thick film electrode formed by applying and firing a conductive paste, a chip type inductance element, or The same can be applied to the chip type thermistor and the chip type varistor.

The structure of the electronic component is not limited to the chip shape, but may be a disc shape or the like, and needless to say, it can be applied to an electronic component having an internal electrode.

[0048]

EXAMPLES Next, examples of the present invention will be specifically described.

[First Embodiment] The plating solution generally contains
In addition to the complexing agent and the metal ion source, a pH adjusting agent, a brightening agent, etc. are added, and it is considered that the adhesion strength of the electrode is most affected by the complexing agent having a large content.

Therefore, the present inventors used citric acid solutions and gluconic acid solutions as complexing agents, and applied different applied potentials to the electrodes to evaluate the superiority and inferiority of the adhesion strength.

That is, the length of the lead titanate powder is 30 m.
A piezoelectric substrate having m, a width of 10 mm, and a thickness of 1 mm was prepared, and then sputtering was performed using a Ni—Cr alloy as a target to prepare a thin film electrode having a film thickness of 0.2 μm, and a test piece was prepared.

Then, the hydrogen ion exponent pH is set to 3.0,
Prepare the prepared citric acid solutions at 4.0 and 5.0 respectively,
The test piece was immersed in a citric acid solution, and the applied potential was adjusted to -0.5 while controlling the potential with a potentiostat using Ag | AgCl as a reference electrode (+0.2 V vs. NHE).
The voltage was set in the range of V to -1.3 V, and the potential was applied for 60 minutes for each applied potential. Then, after this, an adhesive tape was attached to the surface of the thin film electrode, and it was tested whether or not the electrode peels when the adhesive tape is peeled from the test piece.

Table 1 shows the test results. In the figure, ◯ indicates the case where electrode peeling did not occur and adhesion strength was good, and X indicates the case where electrode peeling occurred.

[0054]

[Table 1] As is clear from Table 1, with respect to a citric acid solution having a hydrogen ion exponent pH of 3.0 or more, -0.7 V or-
It was found that the electrode peeling can be prevented by applying an electrochemically nobler potential than 0.7 V to the electrodes.

Next, the present inventors have found that the hydrogen ion concentration p
Gluconic acid solutions prepared by adjusting H to 3.0, 4.0 and 5.0 were prepared, a potential was applied to the test piece in the same manner as described above, and an electrode peeling test was performed.

Table 2 shows the test results. In the figure, ◯ indicates the case where electrode peeling did not occur and the adhesion strength was good, and X indicates the case where electrode peeling occurred.

[0057]

[Table 2] As is clear from Table 2, with respect to a gluconic acid solution having a hydrogen ion exponent pH of 4.0 or more, -0.7 V or-
It was found that the electrode peeling can be prevented by applying an electrochemically nobler potential than 0.7 V to the electrodes.

Therefore, by adjusting the pH of the plating solution to 4.0 or more, not only citric acid but also gluconic acid has a potential of −0.7 V or −0.7 V which is electrochemically nobler than the potential of the electrode. No electrode peeling occurs even when the voltage is applied, and therefore the plating solution is adjusted to pH 4.
It was confirmed that the degree of freedom in selecting the substance species contained in the plating solution is increased by adjusting the amount to 0 or more.

It should be noted that the plating solution having a hydrogen ion exponent pH of less than 3.0 has a large damage to the ceramic body and is obviously unsuitable for use.
The electrode peeling test was not performed for less than.

Second Embodiment Next, the present inventors used various nickel plating solutions and tin plating solutions and applied different potentials to the object to be plated to form a nickel film and a nickel film on the surface of the electrode part. Test pieces having a tin film laminated thereon (Examples 1 to 5)
And Comparative Examples 1 to 5) were prepared and evaluated for electrode peeling, poor conduction, solder wettability, and heat resistance.

[Example 1] First, a piezoelectric substrate molded from lead titanate powder to a length of 3.1 mm, a width of 3.7 mm and a thickness of 0.7 mm was prepared. A dielectric substrate molded to have a thickness of 0.1 mm, a width of 3.7 mm and a thickness of 0.7 mm was produced. Then, the piezoelectric substrate was sandwiched between a pair of upper and lower dielectric substrates and bonded with an adhesive to manufacture a ceramic body.

Then, the ceramic body was sputtered while masking with a Ni--Cr alloy as a target, and thin film electrodes with a thickness of 0.2 μm were formed at the end and center of both side surfaces of the ceramic body. Formed into a shape.

After that, a conductive paste containing Ag powder, a glass component such as borosilicate glass, and an organic vehicle is prepared, and the upper and lower end portions of the ceramic body are connected so that they can be connected to the thin film electrodes. Then, a conductive paste was applied to the substrate and baked to form a thick film electrode having a film thickness of 20 μm, and an object to be plated was prepared.

Next, a nickel plating solution containing nickel sulfate and citric acid as main components and having a hydrogen ion exponent pH of 8.0 was prepared, and the above-mentioned object to be plated was placed in the barrel inserted in the cathode plate. The barrel and nickel plate (anode plate)
Was immersed in the nickel plating solution. And Ag | A
While using gCl as a reference electrode and controlling the potential with a potentiostat so that the applied potential was −0.7 V, electrolysis was performed by applying electricity for 60 minutes between the anode (anode plate) and the cathode (cathode plate). A nickel film having a film thickness of 5 μm was formed on the surfaces of the electrode parts (thin film electrode and thick film electrode).

Then, a tin plating solution containing stannous sulfamate and gluconic acid as main components and having a hydrogen ion exponent pH of 10.0 was prepared, and an anode plate made of tin was used. Was controlled by a potentiostat so as to be −0.7 V, and electrolytic plating was performed to form a tin film having a thickness of 10 μm on the surface of the nickel film.

[Example 2] An object to be plated was prepared by the same procedure as in Example 1, and then a nickel plating solution containing nickel sulfate and glycine as a main component and having a hydrogen ion exponent pH of 9.0 was prepared and carried out. By the same procedure as in Example 1, the applied potential was −0.
Electrolytic plating was performed while controlling the potential with a potentiostat to 6 V to form a nickel film having a thickness of 2 μm on the surface of the electrode portion.

Next, a tin plating solution containing stannous sulfate and gluconolactone as the main components and having a hydrogen ion exponent pH of 8.0 was prepared, and potentiometer was applied so that the applied potential was -0.6 V, as described above. Electrolytic plating was performed while controlling the potential with a stat to form a tin film with a thickness of 3 μm on the surface of the nickel film.

Example 3 An object to be plated was prepared by the same procedure as in Example 1, and then a nickel plating solution containing nickel sulfamate and potassium pyrophosphate as main components and having a hydrogen ion index pH of 8.5 was prepared. Then, in the same procedure as in Example 1, electrolytic plating was performed while controlling the potential with a potentiostat so that the applied potential was −0.7 V, and a nickel film with a thickness of 3 μm was formed on the surface of the electrode portion.

Next, a tin plating solution containing stannous sulfate and sodium gluconate as main components and having a hydrogen ion exponent pH of 9.0 was prepared, and the applied potential was -0.7 as in the above.
Electroplating was performed while controlling the potential with a potentiostat to V, and a tin film having a thickness of 6 μm was formed on the surface of the nickel film.

Example 4 After preparing an object to be plated by the same procedure as in Example 1, a nickel plating solution containing nickel acetate and tartaric acid as main components and having a hydrogen ion exponent pH of 6.0 was prepared and carried out. With the same procedure as in Example 1, the applied potential was -0.7.
Electroplating was performed while controlling the potential with a potentiostat so that V was V, and a nickel film having a film thickness of 5 μm was formed on the surface of the electrode portion.

Then, a tin plating solution containing stannous acetate and sodium pyrophosphate as main components and having a hydrogen ion exponent pH of 8.0 was prepared, and the applied potential was -0.7 as in the above.
Electroplating was performed while controlling the potential with a potentiostat so that V was V, and a tin film having a thickness of 10 μm was formed on the surface of the nickel film.

Example 5 An object to be plated was prepared in the same procedure as in Example 1, and then a nickel plating solution containing nickel sulfate and boric acid as main components and having a hydrogen ion index pH of 4.0 was prepared. The applied potential was -0.7 by the same procedure as in Example 1.
Electroplating was performed while controlling the potential with a potentiostat so that V was V, and a nickel film having a film thickness of 5 μm was formed on the surface of the electrode portion.

Next, a tin plating solution containing stannous sulfamate and gluconic acid as main components and having a hydrogen ion exponent pH of 5.0 was prepared, and the applied potential was -0.7 as in the above.
Electroplating was performed while controlling the potential with a potentiostat so that V was V, and a tin film having a thickness of 10 μm was formed on the surface of the nickel film.

[Comparative Example 1] An object to be plated was prepared in the same procedure as in Example 1, and then a nickel plating solution containing nickel sulfate and boric acid as main components and having a hydrogen ion exponent pH of 4.0 was prepared. The applied potential was -0.9 by the same procedure as in Example 1.
Electroplating was performed while controlling the potential with a potentiostat so that V was V, and a nickel film having a film thickness of 5 μm was formed on the surface of the electrode portion.

Next, a tin plating solution containing stannous sulfate and citric acid as the main components and having a hydrogen ion exponent pH of 5.0 was prepared, and the potentiostat was applied so that the applied potential was -0.9 V, as described above. Electroplating was performed while controlling the electric potential by means of to form a tin film having a film thickness of 10 μm on the surface of the nickel film.

[Comparative Example 2] An object to be plated was prepared in the same procedure as in Example 1, and then a nickel plating solution containing nickel sulfamate and boric acid as main components and having a hydrogen ion index pH of 4.5 was prepared. In the same procedure as in Example 1, electrolytic plating was performed while controlling the potential with a potentiostat so that the applied potential was -1,2 V, and a nickel film with a thickness of 5 μm was formed on the surface of the electrode portion.

Next, a tin plating solution containing stannous sulfamate and cresol sulfonic acid as the main components and having a hydrogen ion exponent pH of 4.0 was prepared, and the applied potential was set to -1.2 V as described above. Electrolytic plating was performed while controlling the potential with a potentiostat to form a tin film with a thickness of 3 μm on the surface of the nickel film.

[Comparative Example 3] An object to be plated was prepared in the same procedure as in Example 1, and then a nickel plating solution containing nickel chloride and boric acid as main components and having a hydrogen ion exponent pH of 4.0 was prepared. In the same procedure as in Example 1, the applied potential was -1,1.
Electroplating was performed while controlling the potential with a potentiostat so that V was V, and a nickel film having a film thickness of 3 μm was formed on the surface of the electrode portion.

Next, a tin plating solution containing stannous acetate and ammonium citrate as main components and having a hydrogen ion exponent pH of 4.0 was prepared, and the applied potential was -1.1 as in the above.
Electroplating was performed while controlling the potential with a potentiostat to V, and a tin film having a thickness of 6 μm was formed on the surface of the nickel film.

[Comparative Example 4] An object to be plated was prepared by the same procedure as in Example 1, and then a nickel plating solution containing nickel sulfate and citric acid as a main component and having a hydrogen ion index pH of 8.0 was prepared. In the same procedure as in Example 1, the applied potential was -1.
Electrolytic plating was performed while controlling the potential with a potentiostat to 0 V to form a nickel film having a film thickness of 5 μm on the surface of the electrode portion.

Then, a tin plating solution containing stannous sulfamate and gluconic acid as main components and having a hydrogen ion exponent pH of 10.0 was prepared, and the applied potential was -1.
Electrolytic plating was performed while controlling the potential with a potentiostat to 0 V to form a tin film with a thickness of 10 μm on the surface of the nickel film.

[Comparative Example 5] An object to be plated was prepared in the same manner as in Example 1, and then a nickel plating solution containing nickel sulfate and boric acid as main components and having a hydrogen ion exponent pH of 4.0 was prepared. In the same procedure as in Example 1, the applied potential was -1.0.
Electroplating was performed while controlling the potential with a potentiostat so that V was V, and a nickel film having a film thickness of 5 μm was formed on the surface of the electrode portion.

Next, a tin plating solution containing stannous sulfate and sodium gluconate as the main components and having a hydrogen ion index pH of 5.0 was prepared, and the applied potential was -1.0 as in the above.
Electroplating was performed while controlling the potential with a potentiostat so that V was V, and a tin film having a thickness of 10 μm was formed on the surface of the nickel film.

In this way, the inventors of the present invention described Examples 1-5.
Also, 10 test pieces of each of Comparative Examples 1 to 5 were produced and evaluated for electrode peeling, presence / absence of conduction failure, solder wettability, and heat resistance.

Here, the peeling of the electrode was evaluated by whether or not the electrode was peeled when the adhesive tape was adhered to the thin film electrodes of each of 10 test pieces and the adhesive tape was peeled off from each test piece.

Continuity failure is -40 ° C. for 30 minutes, 1
The heat shock was repeated by repeating 2000 cycles at 25 ° C. for 30 minutes as one cycle, and the presence or absence of conduction failure was examined.

The solder wettability was evaluated by the meniscograph method at the zero cross time when the tensile force of the solder and the repulsive force of the solder were equal. That is, the immersion speed is 1 mm
/ Sec, immersion depth 0.25 mm, immersion time 5 sec, bath temperature 2
It was immersed in a solder melting bath (60% Sn-40% Pb) at 35 ° C, and the zero cross time was measured to evaluate the solder wettability.

The heat resistance was measured by immersing each test piece in a solder melting bath (60% Sn-40% Pb) at 270 ° C. for 30 seconds, and then measuring the remaining area of the electrode left without melting the solder. When the remaining area is 90% or more, it is good (⊚), when the remaining area is 75% or more and less than 90%, it is acceptable (○), and when the remaining area is 50% or more and less than 75%, it is a little bad ( Δ), and the case where the remaining area was less than 50 was evaluated as bad (x).

Table 3 shows the composition, pH, and film thickness of the plating film of the nickel plating solutions of Examples and Comparative Examples, respectively.
Table 4 shows the composition of the tin plating solution of each Example and Comparative Example, p
H and the film thickness of the plating film are shown respectively, and Table 5 shows the applied potential and the measurement results in each of the examples and comparative examples.

[0090]

[Table 3]

[0091]

[Table 4]

[Table 5] As is clear from Tables 3 to 5, in Comparative Examples 1 to 5, the potential of -0.9V to -1.2V, which is electrochemically base rather than -0.7V, is used as a reference with respect to the standard hydrogen electrode potential. Since the plating process is performed by applying it to the object to be plated, electrode peeling is 3
Occurrence with a probability of 0% to 80%, and conduction failure is also 10% to 50%.
Occurred with a probability of%. It was also confirmed that the probability of electrode peeling or poor conduction increases as the applied potential shifts to the base direction.

Further, in Comparative Examples 1 to 5, since electrode peeling is likely to occur, the zero-cross time is also 2.0 seconds to 4.1.
It was confirmed that it became longer and the solder wettability deteriorated. Particularly, in Comparative Example 2, since the applied potential is base and the film thickness of the nickel film and the tin film are thin, the synergistic effect of these causes the zero crossing time to be extended to 4.1 sec, which deteriorates the solder wettability, and also the heat resistance. It was confirmed that the sex was bad.

On the other hand, in Examples 1 to 5, the plating treatment was performed by applying -0.7 V or a potential electrochemically nobler than -0.7 V to the object to be plated on the basis of the standard hydrogen electrode potential. As a result, no structural destruction of the ceramic body occurs, therefore no electrode peeling or conduction failure occurs, the zero-cross time is as short as 0.8 seconds to 1.7 seconds, solder wettability is good, and heat resistance is high. It was confirmed that the property is also excellent.

[0094]

As described in detail above, in the method for plating an electronic component according to the present invention, the object to be plated having the electrode formed on the surface of the ceramic body is subjected to a plating treatment to form a plating film on the surface of the electrode. In the method of plating an electronic component to be formed, the standard hydrogen electrode potential is used as a reference of -0.7 V or -0.7 V.
Since the plating treatment is performed while applying a potential that is electrochemically nobler than V to the object to be plated, the potential applied to the object to be plated does not become excessively base, and the ceramic body is reductively decomposed. Then, structural destruction can be avoided and the adhesion strength can be improved, whereby an electronic component without peeling of electrodes or defective conduction can be manufactured.

Further, it is preferable that the plating film is made of any one of nickel, tin, and a tin alloy, whereby a desired electronic component having good heat resistance and solder wettability can be obtained. It will be possible.

Further, according to the present invention, the hydrogen ion exponent pH of the plating solution in which the object to be plated is immersed is set to 4 to 10 so that the degree of freedom in selection of the species of substances mixed in the plating solution such as the complexing agent is increased. Can be expanded.

Further, by using the above-mentioned plating method, it is possible to avoid the occurrence of problems such as electrode peeling and conduction failure in both thin film electrodes and thick film electrodes.

The electronic component according to the present invention is manufactured by the manufacturing method described above, and the ceramic body is one type selected from a dielectric material, a piezoelectric material, an insulating material, or a semiconductor material. Since it is formed of the above ceramic material, it is possible to obtain various kinds of high-quality electronic components which are free from electrode peeling and poor conduction and have good heat resistance and solder wettability and which are excellent in reliability.

[Brief description of drawings]

FIG. 1 is a perspective view of a chip-type ceramic oscillator as an embodiment of an electronic component according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a schematic view of a wet electrolytic barrel plating apparatus.

[Explanation of symbols]

3 Ceramic body 5a thick film electrode 5b thin film electrode 6 electrodes 7 Nickel coating (plating coating) 8 Tin film (plating film)

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Claims (7)

[Claims] 1. A method for plating an electronic component, wherein an object to be plated having an electrode formed on the surface of a ceramic body is subjected to a plating treatment to form a plating film on the surface of the electrode, wherein a standard hydrogen electrode potential is used as a reference. A plating method for an electronic component, which comprises performing a plating treatment while applying a potential electrochemically nobler than 0.7 V or -0.7 V to the object to be plated. 2. The plating film is made of nickel, tin, or a tin alloy.
A method for manufacturing the described electronic component. 3. A method for plating an electronic component, wherein the plating solution in which the object to be plated is immersed has a hydrogen ion exponent pH of 4 to 10. 4. The electrode is a thin film electrode manufactured by performing a sputtering process.
A method for plating an electronic component according to claim 3. 5. The thick electrode according to claim 1, wherein the electrode is a thick film electrode prepared by applying and baking a conductive paste containing a conductive material and a glass component. The method for plating an electronic component according to any one of the above. 6. An electronic component manufactured using the plating method according to any one of claims 1 to 5. 7. The ceramic body is formed of at least one ceramic material selected from a dielectric material, a piezoelectric material, an insulating material, or a semiconductor material. Electronic components listed.