JPH11200097A - Barrel plating method for chip parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the sticking defects of chip parts to each other by feeding a multiplicity of the chip parts to be formed with plating layers, regulators of nonconductors of the same shape as the shape of these chip parts and a multiplicity of metallic power feeders for anion conduction into the barrel of a barrel plating apparatus. SOLUTION: A multiplicity of the chip resistors 7 to be formed with the plating layers, a multiplicity of the power feeders 8 consisting of balls made of conductive metals of a size smaller than the size of the resistors and the chip-shaped regulators 9 of the nonconductors of the same shape as the shape of the chip resistors 7 are simultaneously fed into the barrel 4 for the barrel plating apparatus 6. The amt. of the regulators 9 to be fed is preferably 50 to 200% of the amt. of the chip resistors 7 to be fed. While the barrel 4 is immersed into a plating vessel 2 housing the plating liquid 1 and is rotated, the electric current is supplied between a cathode lead wire 3 disposed in the barrel 4 and a metallic anode 5 in the plating liquid 1. As a result, the chip resistors 7 to which anion is conducted via the power feeders 8 are plated without the occurrence of the sticking defects.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a barrel plating method for chip components used in high-density wiring circuits.

[0002]

2. Description of the Related Art A conventional barrel plating method will be described below, taking a chip resistor as an example of an electronic component.

[0003] Electrode plating of a chip resistor is performed by a barrel plating method using a barrel plating apparatus. That is, a large number of chip resistor elements to be formed with a plating layer are placed in a barrel together with a large number of power supply elements made of conductive metal balls commonly called dummy and an agitation accelerator made of ceramic balls and the like. It is carried out by turning on and rotating them in the plating solution, and energizing between the cathode lead wire inserted in the barrel and the metal anode arranged outside the barrel for a predetermined time.

The metal dissolved and ionized from the metal anode precipitates on the electrode surface of the chip resistor body to which a negative potential is applied via a cathode lead wire or a dummy.
A plating layer is formed.

Here, the dummy plays a role of a current supply path for uniformly applying a negative potential to all of a large number of chip resistor elements dispersed in the barrel from the linear cathode contact. Further, the stirring promoting body has a role of improving stirring efficiency in the barrel and suppressing a variation in plating film thickness of a large number of chip resistor elements.

[0006]

However, in the conventional barrel plating method for chip components, chip components may adhere to each other after plating and may not be separated as individual chip components. If you forcibly remove the chip components that are attached in this way into individual chip components, problems such as electrode peeling may occur. There was a problem that it could not be separated into parts.

SUMMARY OF THE INVENTION An object of the present invention is to provide a barrel plating method for chip components, which can drastically reduce sticking defects between chip components.

[0008]

In order to achieve the above object, a method of barrel plating a chip component according to the present invention comprises the steps of: forming a plurality of chip components for forming a plating layer in a barrel of barrel plating; And a non-conductive adjuster and a number of metal feeders that conduct anions in the barrel.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a method of forming a plating layer on a chip component by barrel plating, wherein a plurality of plating layers to be formed in a barrel of barrel plating are formed. A chip component, an adjusting body having the same shape as the chip component, and a large number of metal feeders that conduct anions in the barrel are charged and plated to reduce a sticking defect between the chip components. It has the effect of becoming

[0010] The invention described in claim 2 of the present invention provides:
The adjustment body according to claim 1 has the same shape as the chip component on which the plating layer is to be formed, and is a non-conductive material, and the alumina substrate which is a base body such as a chip resistor is divided as it is,
This has an effect that an individual chip can be used as an adjusting body.

Further, the invention according to claim 3 of the present invention provides:
The input amount of the adjusting member according to claim 1 is 50% or more and 200% or less of the input amount of the chip component on which the plating layer is to be formed, and it is possible to reduce sticking defects between the chip components. It has the action of:

Hereinafter, a method for barrel plating chip components according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a barrel plating apparatus for barrel plating according to an embodiment of the present invention. FIG.
FIG. 2A is a perspective view of an adjusting body as the main part, FIG. 2B is a perspective view of a chip resistor as an example of the electronic part as the main part, and FIG. 3 is a process diagram illustrating the same step. is there.

The barrel plating apparatus 6 includes a plating tank 2 for storing a plating solution, and a perforated barrel 4 dipped in the plating tank 2 and rotated. The barrel 4 is detachably attached to a cathode electrode saddle provided at an end of the plating tank 2, and the cathode lead wire 3 electrically connected to the cathode electrode saddle is connected to the barrel 4. It is inserted and installed inside. The metal anode 5 is immersed in the plating solution 1 outside the barrel 4. The cathode electrode saddle and the metal anode 5 are connected to respective terminals of a cathode and an anode of a rectifier (not shown).

In the barrel plating method for a chip resistor according to an embodiment of the present invention, first, a 3216 type chip resistor 7 (3.2) for forming a plating layer in the barrel 4 is formed.
× 1.6 × 0.6 mm), 2 kg, and a feeder 8 made of conductive balls smaller than the chip resistor 7, 5 kg, and the same shape (3.2 × 1.6 × 0) as the chip resistor 7. Step A, in which 2 kg of a chip-shaped adjusting member 9 made of alumina having a diameter of 0.6 mm) is simultaneously introduced.

Next, a degreasing step B for removing oils and fats and dust and the like is performed while rotating the barrel 4, and a water washing C is performed. Then, an acid treatment step D for activating the surface and removing the oxide film is performed, and a washing E is performed.

Next, the Ni plating step F is performed at a current density of 1-1.
Perform at 0 A / dm ² for 50 minutes. Next, after performing washing G, the solder plating step H was performed at a current density of 1 to 10 A / dm.
Perform for 40 minutes as ² .

Next, washing with water I is performed, and a discoloration preventing treatment J with a 5% aqueous solution of tribasic sodium phosphate is performed.
I do.

Next, after performing the step L of taking out the chip resistor 7, the power supply 8 and the adjustment body 9 from the barrel in a basket for drying, the drying M is performed.

The results of comparing the sticking rates of the chip resistors after plating by the conventional barrel plating method and the barrel plating method in the present embodiment will be described below.
Table 1 shows the sticking ratio of the chip resistor when the input amount of the adjuster is changed with respect to the product amount in the conventional barrel plating method and the barrel plating method of the present invention. Here, the sticking rate means an overlapping (stuck state) defect rate of products generated in one barrel.

[0021]

[Table 1]

As is clear from Table 1, the sticking rate of the chip resistor plated by the barrel plating method in the embodiment of the present invention is 1% or less, which is much smaller than the conventional method. Can be reduced. In the case of chip resistors, in particular, in the case of chip resistors, the back surface tends to overlap due to the surface tension of water. It is thought to lead to failure. For this reason, the dummy which is non-conductive and has the same shape as the product is constantly and intentionally brought into contact with the chip resistors, thereby reducing the probability of contact between the chip resistors and thereby suppressing the occurrence of sticking failure. I have.

When the amount of the adjuster is less than 50% of the product input, the smaller the adjuster, the higher the sticking rate. On the other hand, if it exceeds 200%, the effect of inhibiting the formation of the plating film by the adjustment body becomes too large, and it becomes difficult to form a sufficient film thickness on the chip resistor with the conventional integrated amount of electricity. In other words, 200
Injecting an amount exceeding% results in another adverse effect, which is not an appropriate condition.

Therefore, by plating the chip parts by the barrel plating method of the present invention, it is possible to greatly reduce sticking defects after plating without changing other conditions at all.

Although one embodiment of the present invention has been described using a chip resistor, the same applies to other chip resistors such as a multiple chip resistor and other chip components such as a chip capacitor. The effect of is obtained.

[0026]

According to the present invention, by adding a non-conductive adjusting body having the same shape as a large number of chip components to be formed with a plating layer into a barrel of a barrel plating apparatus, It is possible to drastically reduce sticking defects between chip components without changing plating conditions at all.

Therefore, not only the trouble of separating the attached chip parts as individual chip parts is reduced, but also the problem of electrode peeling due to unraveling or the like is eliminated, and the yield and quality reliability are improved. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a barrel plating apparatus for barrel plating according to an embodiment of the present invention.

FIG. 2 (a) is a perspective view of an adjusting body which is the main part. FIG. 2 (b) is a perspective view of a chip resistor which is the main part.

[Fig. 3]

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plating solution 2 Plating tank 3 Cathode lead wire 4 Barrel 5 Metal anode 6 Barrel plating device 7 Chip resistor 8 Feeder 9 Adjuster

Claims (3)

[Claims] 1. A method of forming a plating layer on a chip component by barrel plating, wherein a plurality of chip components on which the plating layer is to be formed, an adjusting body having the same shape as the chip component, and A barrel plating method for a chip component in which a plurality of metal feeders that conduct anions in the barrel are charged and plated. 2. The barrel plating method for a chip component according to claim 1, wherein the adjusting body has the same shape as the chip component on which the plating layer is to be formed, and is non-conductive. 3. The barrel plating method for a chip component according to claim 1, wherein the input quantity of the adjusting member is 50% or more and 200% or less of the input quantity of the chip component for forming the plating layer.