KR20050073172A - Test method for permeation of plating solution into terminal electrode of chip device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting penetration of a plating liquid into terminal electrodes, such as chip components.

According to an aspect of the present invention, there is provided a chip component having a plated layer formed on a terminal electrode and an outer surface of the terminal electrode, exposing a cross section of the terminal electrode, and selectively etching and removing components constituting the terminal electrode. It provides a method for testing the plating liquid penetration of the chip component terminal electrode comprising the step of removing the components constituting the terminal electrode and the remaining portion.

According to the present invention, it is inexpensive for a short time and has an advantage of accurately determining whether or not the penetration of the plating liquid in the terminal electrode.

Description

TEST METHOD FOR PERMEATION OF PLATING SOLUTION INTO TERMINAL ELECTRODE OF CHIP DEVICE}

The present invention relates to a method for inspecting the penetration of a plating liquid into a terminal electrode such as a chip component. More specifically, the penetration of the plating liquid of a nickel component with pores existing in copper used as a terminal electrode can be accurately and at low cost. The present invention relates to a plating liquid penetration inspection method of a chip component terminal electrode that can be inspected.

In general, as shown in FIG. 1, a chip component, such as a multilayer capacitor, fabricates a body 1 by stacking a plurality of sheets on which a pattern is printed, and then, for electrical connection with an external circuit or the like on the surface of the body 1. The terminal electrode 2 is printed. Subsequently, after the terminal electrode baking process is performed for densification of the printed terminal electrode 2, the nickel plating layer 3 and the solder plating layer 4 are formed to provide solderability of the terminal electrode, thereby forming chip components. Will complete.

Conventionally, palladium (Pd) is used as a material of the internal electrode, and silver (Ag) or silver-palladium is used as the terminal electrode, but recently, nickel (Ni) is used as the internal electrode material instead of expensive palladium and the terminal electrode is used. As a material of, a small amount of glass frit is mixed with copper (Cu) and used. In the terminal electrode made of such a copper material, porosity exists as shown in FIG. 2. FIG. 2 is an enlarged view of a portion A of the terminal electrode and the plating layer of FIG. 1, and as described above, the terminal electrode 2 is printed on the surface of the body 1 for densification of the terminal electrode 2. Even if the baking process of the terminal electrode 2 is performed, it is impossible to remove all the pores 22 and 23 in the copper 21 which is the main material of the terminal electrode. Some of the pores are softened and filled by the glass flit 22 used with copper, but the pores still exist in the terminal electrode.

The pores present in the copper 21 used as the material of the terminal electrode 2 do not deteriorate the characteristics of the chip component by themselves, but after the baking process of the terminal electrode 2, When the plating layer 3 is formed on the outer surface using nickel, the liquid plating solution penetrates into pores inside the terminal electrode. Due to the plating solution 23 penetrating the pores, there is a problem that deteriorates the electrical characteristics and soldering characteristics of the chip component after plating and lowers the reliability of the product. Therefore, it is necessary to check the characteristics of the manufactured chip component by checking whether the plating liquid penetrates into the terminal electrode and the extent thereof after manufacturing the chip component.

In general, it is very difficult to accurately distinguish between nickel used as a material of a plating layer and copper, which is a material of a terminal electrode, in a plated terminal electrode. Particularly, penetration of nickel (plating solution) penetrated into the copper (terminal electrode) is performed. Checking the degree is a more difficult analysis. Conventionally, in order to confirm the degree of penetration of the plating solution into the terminal electrode, the distribution of the penetration of the plating solution inside the terminal electrode was analyzed by scanning a portion where the terminal electrode is formed using an equipment called Energy Dispersive X-ray Spectroscopy (EDS). The EDS can analyze the plating solution penetration distribution inside the terminal electrode very precisely, but only one specimen per EDS can be analyzed, and there is a problem in that one analysis takes a long time of 1 to 2 hours. In particular, the EDS is a very expensive analysis equipment, which has a problem that cannot be actually used at each manufacturing site.

When such expensive EDS equipment is not available, a simple method called popcorn test is sometimes used to measure the penetration of plating solution simply at the chip component manufacturing site. The popcorn test is a method of observing a phenomenon in which the plating liquid component bursts while directly heating a plated chip component with a candle or the like, and can easily check whether the plating liquid penetrates without using expensive equipment. However, since the method of observation is a primitive method of relying on the auditor's hearing and vision of the sound and heating phenomenon of the plating layer, the accuracy is very low, and the criterion of the tester is not constant. In particular, the penetration of the plating liquid can be grasped, but there is a problem in that it is not possible to accurately check how much penetration has occurred.

Therefore, in the art, it is possible to inspect the plating liquid penetration into the terminal electrode within a short time without using expensive equipment, and at the same time, the plating liquid penetration inspection of the new chip component terminal electrode capable of accurately identifying the plating liquid penetration and the degree of penetration. There is a need for a method.

The present invention has been made to solve the above problems, the plating solution penetration inspection of the chip component terminal electrode that can easily inspect the plating liquid component penetrated therein by an optical microscope by selectively etching and removing only the terminal electrode of the chip component The purpose is to provide a method.

The present invention as a technical configuration for achieving the above object,

Providing a chip component having a plating layer formed on a terminal electrode and an outer surface of the terminal electrode;

Exposing a cross section of the terminal electrode;

Selectively etching and removing components constituting the terminal electrode; And

It provides a plating solution penetration inspection method of the chip component terminal electrode comprising the step of removing the components constituting the terminal electrode and the remaining portion.

Preferably, the method further comprises molding the exterior of the chip component prior to exposing the cross section of the terminal electrode, and net cleaning the etched portion after the selectively etching and removing.

In a preferred embodiment of the present invention, the component of the plating layer is nickel (Ni), the component of the terminal electrode is copper (Cu), and the step of selectively etching to remove, the etching liquid mixed with distilled water, ammonia and hydrogen peroxide The chip component exposed to the end surface of the terminal electrode is immersed in the step, thereby selectively etching and removing the components constituting the terminal electrode component.

Hereinafter, an embodiment of a plating liquid penetration test method of a chip component terminal electrode according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a flow chart of an embodiment of a plating liquid penetration test method of a chip component terminal electrode according to the present invention. Referring to FIG. 3, a plating solution penetration inspection method of a chip component terminal electrode according to an embodiment of the present invention may be described in detail. First, a step of preparing a chip component having a plating layer formed on a terminal electrode and an outer surface of the terminal electrode (not shown), molding the outside of the chip component (S31), and exposing the chip to expose a cross section of the terminal electrode. Cutting the component (S32), selectively etching and removing the components constituting the terminal electrode (S33), purely washing the etched portion (S34) and the components constituting the terminal electrode It is configured to include a step (S36) to check the remaining portion is removed.

First, in the step (not shown) of preparing a chip component having a plating layer formed on an outer surface of the terminal electrode and the terminal electrode, a general chip component in which a terminal electrode and an outer surface of the terminal electrode are plated on an exterior, such as a multilayer capacitor, may be used. Prepare. Usually, the component which comprises the said terminal electrode is copper (Cu), and the component which comprises the said plating layer is nickel (Ni). One embodiment of the present invention described below relates to a multilayer capacitor in which copper is used as a material of a terminal electrode and nickel is used as a material of a plating layer.

After preparing the chip component, the outside of the chip component may be molded (S31). Molding the outside of the chip component is intended to remove only the desired portion through etching and not to remove the remaining portion when the chip component is subsequently immersed in the etching liquid. The molding may be performed using a general epoxy-based molding liquid.

Next, the cross section of the chip component terminal electrode is exposed (S32). Exposing the end face of the terminal electrode is for observing a plating liquid component immersed in the inside of the terminal electrode, and exposes the end face of the terminal electrode to the portion to be observed. As a method of exposing the end surface of the terminal electrode, a method of polishing the chip component to a position to be observed using SiC abrasive paper and a method of cutting the chip component using a laser may be used.

Subsequently, the components constituting the terminal electrode are selectively etched and removed (S34). Removing the components constituting the terminal electrode through the etching (copper in this embodiment) is a main feature of the present invention, by selectively removing only the copper component through the component control of the etching solution, the plating layer penetrated inside the terminal electrode By not removing the component (nickel in this embodiment), the plating liquid penetrated into the pores inside the terminal electrode can be inspected. The etching is performed by removing the plating layer and immersing the chip component with the terminal electrode exposed in a predetermined etching solution.

As described above, according to the present invention, the plating liquid component penetrated into the terminal electrode can be detected by immersing the chip component in the etching liquid, so that the plating liquid component penetrated into the terminal electrode can be inspected relatively simply. Samples can be immersed, allowing a large number of samples to be examined at the same time.

In addition, in the etching process, the etching thickness may be adjusted according to the components of the etching solution and the etching time. Therefore, the penetration of the plating liquid according to the position of the chip component terminal electrode can be inspected by adjusting the components of the etching solution and the etching time.

Component and etching time of the etching solution that can be applied to the present invention will be described in more detail with reference to the examples described below.

Subsequently, the etched portion of the chip component is purely washed using distilled water or the like to remove the etchant remaining on the surface of the etched chip component.

The etched portions of the chip components are then inspected for remaining plating layer components using an optical microscope or the like. Since the copper component forming the terminal electrode is removed through the etching, the plating liquid component (nickel) that has penetrated the pores inside the terminal electrode remains exposed to the outside in the etched portion of the chip component. In this way, since the nickel component that has penetrated into the terminal electrode is exposed as it is, the nickel component can be easily observed through a general optical microscope without using an analytical equipment.

The inventors of the present invention have repeatedly experimented to investigate the components and etching times of the preferred etchant used to selectively remove the terminal electrode components. Hereinafter, the components and the etching time of the etching solution used in the present invention will be described through two examples.

Example 1

This embodiment is an experiment for investigating the components of the etch solution used to selectively remove the terminal electrode components. The etchant used in the present invention was used by mixing distilled water, ammonia and hydrogen peroxide (H ₂ O ₂ ). In addition to hydrogen peroxide, hydrochloric acid and sulfuric acid may be used as the oxidizing agent, but hydrochloric acid or sulfuric acid may cause rapid oxidation to remove not only copper terminal electrodes but also nickel, which is a plating solution component penetrated therein, and thus, hydrogen peroxide may be used as an oxidizing agent. It is desirable to. The results shown in Table 1 below show that the amount of distilled water and ammonia equal to 25 g and the amount of hydrogen peroxide changed from 0 g to 20 g while changing the components of the nicking liquid, the plating liquid penetrating into the terminal electrode components and copper The etching degree of nickel which is a component is shown. In Table 1, the amounts of distilled water, ammonia, and hydrogen peroxide were expressed in weight%, and the time of immersing the sample (the multilayer capacitor cut to expose the cross section of the terminal electrode) in the nicking liquid was 30 seconds.

turn Amount of distilled water (% by weight) Amount of ammonia (% by weight) Amount of hydrogen peroxide (% by weight) Copper etching thickness (㎛) Nickel Etching Thickness (㎛) One 50 50 0 0 0 2 48 48 4 0 0 3 46 46 8 0 0 4 45 45 10 3.1 0 5 43 43 14 7.8 0 6 42 42 16 13.2 0 7 40 40 20 15.3 0.1 8 39 39 22 19.2 0.2 9 38 38 24 23.1 0.5 10 37 37 26 28.6 0.8 11 36 36 28 35.4 1.3

As shown in Table 1, when the component of the hydrogen peroxide is less than 10% by weight, the etching of copper hardly occurs, when the component of the hydrogen peroxide is more than 20% by weight of nickel etching occurs. In this embodiment, when the sample is immersed in the etchant for 30 seconds, when the immersion time is increased or decreased, the component ratio of hydrogen peroxide can be reduced or increased accordingly. Therefore, the etching solution used in the present invention is a mixture of distilled water, ammonia and hydrogen peroxide, the component of the hydrogen peroxide is preferably 5% to 35% by weight, most preferably 10% to 20% by weight.

Example 2

This example is an experiment for examining the etching thickness of copper and nickel by varying the time for immersing the sample in the etchant of the component shown in Example 1. Table 2 shows a sample (multilayer capacitor cut to expose the end face of the terminal electrode) in an etching solution mixed at a ratio of 42% by weight of distilled water, 42% by weight of ammonia and 16% by weight of hydrogen peroxide for 1 second to 600 seconds. The etching thicknesses of copper and nickel are recorded. In Table 2, the elapsed time of etching was expressed in seconds, and the etching thicknesses of copper and nickel were expressed in μm.

turn Etching Elapsed Time (sec) Copper etching thickness (㎛) Nickel Etching Thickness (㎛) One One 0.5 0 2 5 1.3 0 3 10 3.7 0 4 15 6.2 0 5 20 8.6 0 6 30 13.2 0 7 40 16.5 0.1 8 50 18.8 0.3 9 70 22.1 0.3 10 90 26.5 0.4 11 110 30.8 0.6 12 150 38.8 0.9 13 190 48.5 1.3 14 230 59.1 2.5 15 310 75.3 3.4 16 390 91.2 6.2 17 470 120.5 9.3 18 600 165.5 12.3

As shown in Table 2, the quenching time should be performed for at least 10 seconds until the copper is etched to an extent that can be observed with an optical microscope (about 3 µm or more). In addition, when etching is performed for 310 seconds, even though nickel is excessively etched so that nickel does not penetrate into the terminal electrode made of copper, the penetration of nickel may not be observed. Therefore, etching is not performed for about 300 seconds or more. . Therefore, in order to selectively etch only copper as the terminal electrode component in the present invention, the etching is preferably performed for about 10 seconds to 300 seconds.

As described above, the plating solution penetration inspection method of the chip component terminal electrode according to the present invention can observe the plating liquid component penetrating into the terminal electrode within a few tens of seconds to several hundred seconds, thereby inspecting the plating liquid penetration of the chip component terminal electrode in a short time. can do.

The present invention is not limited by the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims, and various forms of substitution, modification, and within the scope not departing from the technical spirit of the present invention described in the claims. It will be apparent to those skilled in the art that changes are possible.

As described above, according to the present invention, the penetration of the plating liquid of the terminal electrode can be inspected without using expensive equipment such as the conventional EDS, thereby reducing the cost of the inspection. In addition, the conventional analytical equipment, such as EDS was able to inspect only one sample for several hours, while according to the present invention can test a plurality of samples at the same time for a short time of tens of seconds to hundreds of seconds to prevent the penetration of the plating liquid This has the advantage of saving time for inspection. Furthermore, there is an advantage that can accurately determine whether the plating solution penetrates and the degree of penetration at low cost for a short time.

1 is a cross-sectional view of a general chip component.

2 is an enlarged cross-sectional view of a terminal electrode in which plating liquid permeation has occurred.

3 is a flowchart of an embodiment of a plating liquid penetration inspection method of a chip component terminal electrode according to the present invention.

* Description of the symbols for the main parts of the drawings *

1: body 2: terminal electrode (Cu)

3: plating layer (Ni) 22: glass component filled in the pores

23: plating layer component immersed in the pores

Claims (5)

Providing a chip component having a plating layer formed on a terminal electrode and an outer surface of the terminal electrode; Exposing a cross section of the terminal electrode; Selectively etching and removing components constituting the terminal electrode; And And inspecting a remaining portion after the components constituting the terminal electrode are removed. The method of claim 1, And molding the outside of the chip component prior to exposing the cross section of the terminal electrode. The method of claim 1, And selectively washing the etched portion after the selectively etching and removing the plating liquid penetration test method of the chip component terminal electrode. The method of claim 1, The plating layer component is nickel (Ni), and the component of the terminal electrode is copper (Cu), the plating solution penetration inspection method of the chip component terminal electrode. The method of claim 1, The step of selectively etching removes the chip component having the end surface of the terminal electrode exposed to an etchant mixed with distilled water, ammonia and hydrogen peroxide to selectively etch and remove the components constituting the terminal electrode component. Plating solution penetration inspection method of the chip component terminal electrode, characterized in that.