CN113512743B

CN113512743B - Blind hole electroplating method for smart card carrier band

Info

Publication number: CN113512743B
Application number: CN202111071236.0A
Authority: CN
Inventors: 张成彬; 刘恺; 陈庆颖; 王毅
Original assignee: New Henghui Electronics Co ltd
Current assignee: New Henghui Electronics Co ltd
Priority date: 2021-09-14
Filing date: 2021-09-14
Publication date: 2021-12-10
Anticipated expiration: 2041-09-14
Also published as: CN113512743A

Abstract

The invention belongs to the technical field of electroplating, and particularly relates to an electroplating method for blind holes of a carrier tape of an intelligent card. The invention provides a physical process method to solve the problem of blind hole electroplating, avoids the problem of service life reduction of a plating solution caused by using a chemical additive, and solves the problem of failure of a smart card product in the aspects of wire bonding and the like due to the reduction of the purity of a plating layer.

Description

Blind hole electroplating method for smart card carrier band

Technical Field

The invention belongs to the technical field of electroplating, and particularly relates to a method for electroplating blind holes of a smart card carrier band.

Background

In the production process of the smart card carrier tape, other metals such as copper, nickel, gold and the like need to be electroplated on the carrier tape. Due to the design characteristics of the carrier tape product, some electroplating positions are planar electroplating, and some electroplating positions are blind hole electroplating. The prior electroplating process is easy to cause plating leakage when the blind hole is electroplated, namely the defect that target metal cannot be electroplated in the blind hole is overcome, thereby causing the product failure.

The prior art realizes blind hole electroplating by adding a chemical wetting agent into a plating solution to reduce the surface tension of the plating solution, and the method increases the content of organic matters in the plating solution due to the addition of the chemical additive, so that codeposition appears in a plating layer, the service life of the plating solution is shortened, the purity of the plating layer is reduced, and the problem of welding failure occurs in the welding process of an intelligent card, thereby affecting the product performance.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method overcomes the defects of the prior art, provides the method for electroplating the blind holes of the intelligent card carrier band, avoids the negative effects of the traditional chemical wetting agent on the service life of the plating solution and the purity of the plating layer, solves the problem of electroplating the blind holes in a physical mode, and does not influence the weldability and other performances of the carrier band.

The technical scheme adopted by the invention for solving the technical problems is as follows: the method for electroplating the blind hole of the carrier tape of the smart card is provided by utilizing the similar compatibility characteristic of a liquid interface, a power spraying device is used before a carrier tape product enters formal plating solution for electroplating, plating solution in a female tank is extracted and sprayed to the blind hole area of the product by using pressure, and the plating solution is contacted with the plating solution in advance in the blind hole by utilizing the principles of high temperature, high pressure and plating solution convection. After the treated product enters into the formal electroplating plating solution, the same plating solution is used for soaking pretreatment, so that the surface tension between the blind hole and the plating solution for formal electroplating is extremely low, the blind hole can be smoothly filled with the plating solution, and the aim of normal electroplating of the blind hole is fulfilled.

In order to achieve the desired effect, the selected power spraying device needs to provide sufficient pressure and adjust the incident angle to a good coverage blind hole. When the product is normally produced, firstly, the product passes through the high-pressure spraying area, the power spraying device can pump the electroplating solution in the mother tank to be sprayed in the blind hole in a high-pressure mode, the electroplating solution can enter the blind hole in a high-flow-rate state due to the temperature and the spraying pressure of the electroplating solution, and the electroplating solution can be completely soaked into the blind hole under the action of continuous pressure; and the infiltrated blind hole continues to move to the electroplating bath, plating solution in the blind hole and plating solution in the electroplating bath can be smoothly blended together, so that the blind hole is filled with the electroplating solution, and target metal is smoothly deposited under the action of current, thereby completing electroplating of the blind hole.

The specific process is as follows:

oil removal: cleaning the surface of the product by adopting ultrasonic and cathode electrolysis degreasing, hot alkali (sodium hydroxide) degreasing or finished product degreasing powder degreasing processes, preferably cleaning the surface of the product by using a plating piece cathode electrolysis hydrogen evolution reaction by using ultrasonic and cathode electrolysis degreasing processes, and 2H⁺+2e^-=H₂。

And (3) activation: the surface of the product is acid-washed with an acid (preferably sulfuric acid) or a finished activating salt to remove any oxide film that may be present on the surface.

When the carrier tape needs nickel plating:

power spraying and infiltrating: and a spraying device is used, electroplating solution in the nickel plating bath mother tank is pumped by a circulating pump, high-pressure spray is formed by the spraying device to soak the blind hole surface of the product, and the blind hole is completely soaked by the nickel electroplating solution.

Nickel plating: and a nickel plating system of watt nickel or nickel sulfamate is used for nickel plating and electroplating, the plating solution in the plating tank can be completely contacted with the soaked blind holes and is subjected to liquid medicine exchange under the action of an upper water pump, so that the product is connected with a direct-current power supply cathode, and nickel metal is added into the titanium basket as an anode to carry out nickel electroplating on the product.

When the carrier tape needs gold plating:

power spraying and infiltrating: and a spraying device is used, the electroplating solution in the gold plating groove mother groove is pumped by a circulating pump, and high-pressure spray is formed by the spraying device to soak the blind hole surface of the product, so that the blind hole is completely soaked by the gold electroplating solution.

Gold plating: the gold plating is carried out by using a citric acid system gold plating formula or a finished product gold plating formula, the plating solution in the plating tank can be completely contacted with the soaked blind holes and is subjected to liquid medicine exchange under the action of an upper water pump, so that the product is connected with a direct current power supply cathode, and a platinum titanium mesh or a gold plate is used as an anode to carry out gold electroplating on the product.

And (4) finishing electroplating: and (5) cleaning and drying to finish electroplating.

Preferably, the jet flow of the power spray is 10-100L/min, and the jet pressure is 1-20 bar; the temperature of the plating solution in the plating bath is 30-70 ℃.

Compared with the prior art, the invention has the following beneficial effects:

the invention solves the problem of blind hole electroplating through a physical process, avoids the problem of service life reduction of a plating solution caused by using a chemical additive, and solves the problem of failure of intelligent card products in the aspects of wire bonding and the like due to the reduction of plating layer purity.

Drawings

FIG. 1 is a schematic diagram of a conventional electroplating process;

FIG. 2 is a schematic process flow diagram of the present invention;

FIG. 3 is a schematic structural view of a power spraying and electroplating apparatus according to the present invention;

FIG. 4 is a perspective view of FIG. 3;

in the figure: 1. carrying a belt; 2. blind holes; 3. a spraying device; 4. and (4) electroplating bath.

Detailed Description

The invention is further described below with reference to the accompanying drawings and examples.

Example 1

A blind hole nickel plating carrier belt with the length of 3 meters is adopted as a base material product, and soft gold electroplating is carried out on a product to be electroplated after oil removal and activation treatment.

The soft gold plating solution is soft gold liquid medicine of German electronic materials Co, the plating solution temperature is 65 ℃, and the gold salt concentration is 10 g/L.

As shown in fig. 3-4, the spraying device 3 extracts the gold plating solution in the electroplating bath 4, sets the temperature at 65 ℃, the spraying pressure at 10bar and the spraying flow at 50L/min, and performs infiltration pretreatment on the carrier tape 1 at the production speed of 4m/min, so that the plating solution is fully infiltrated in the blind holes 2; the product continuously enters the electroplating bath 4 at the same speed for electroplating; the electroplating current of the electroplated soft gold is 1A, the effective electroplating time of the electroplating tank is 20s, and the product is dried after the electroplating is finished.

Example 2

A blind hole nickel plating carrier belt with the length of 3 meters is adopted as a base material product, and soft gold electroplating is carried out on the product to be electroplated after oil removal and activation.

As shown in fig. 3-4, the spraying device 3 extracts the gold plating solution in the electroplating bath 4, sets the temperature at 65 ℃, the spraying pressure at 2bar and the spraying flow at 10L/min, and performs infiltration pretreatment on the carrier tape 1 at the production speed of 4m/min, so that the plating solution is fully infiltrated in the blind holes 2; the product continuously enters the electroplating bath 4 at the same speed for electroplating; the electroplating current of the electroplated soft gold is 1A, the effective electroplating time of the electroplating tank is 20s, and the product is dried after the electroplating is finished.

Example 3

As shown in fig. 3-4, the spraying device 3 extracts the gold plating solution in the electroplating bath 4, sets the temperature at 65 ℃, the spraying pressure at 20bar and the spraying flow rate at 100L/min, and performs infiltration pretreatment on the carrier tape 1 at the production speed of 4m/min, so that the plating solution is fully infiltrated in the blind holes 2; the product continuously enters the electroplating bath 4 at the same speed for electroplating; the electroplating current of the electroplated soft gold is 1A, the effective electroplating time of the electroplating tank is 20s, and the product is dried after the electroplating is finished.

Comparative example 1

And removing the spraying device 3, adopting a blind hole nickel plating carrier belt with the length of 3 meters as a base material product, and carrying out soft gold electroplating on the product to be electroplated after oil removal and activation.

The soft gold plating solution is soft gold liquid medicine of German electronic materials Co, the plating solution temperature is 65 ℃, and the gold salt concentration is 10 g/L. Electroplating at the production speed of 4m/min, wherein the electroplating current of the electroplated soft gold is 1A, the effective electroplating time of the electroplating tank is 20s, and drying the product after electroplating.

Comparative example 2

The soft gold plating solution is soft gold liquid medicine of German electronic materials Co, the plating solution temperature is 65 ℃, and the gold salt concentration is 10 g/L. Adding 4ml/L wetting agent into the soft gold plating solution, and fully circulating the plating solution; electroplating at the production speed of 4m/min, wherein the electroplating current of the electroplated soft gold is 1A, the effective electroplating time of the electroplating tank is 20s, and drying the product after electroplating.

And (3) performance testing:

and (3) testing the plating omission fraction defective: and (3) visually detecting all blind holes by using a new constant-current appearance detector, judging NG of the blind holes which are not plated with gold as the plating missing defects, judging OK of products which are normally plated with gold, and counting as follows:

item	Example 1	Example 2	Example 3	Comparative example 1	Comparative example 2
						Total number of blind holes	21253	20482	21557	21048	22014
Number of NG blind holes	0	18	0	549	5
						Fraction defective ‰ o	0	0.88	0	26.08	0.23

The detection results clearly show that the blind hole plating leakage problem can be effectively improved in the

embodiments

1 and 3, and the reject ratio is 0; whereas, in the embodiment 2, the plating leakage occurs after the spraying pressure flow is reduced, and the embodiment 2 is not the optimal scheme of the invention; in the comparative example 1, no improvement measure is used at all, and the defective rate of blind hole plating leakage is 26.08 per mill which is obviously higher than that of other cases; in comparative example 2, the addition of the wetting agent reduced the defective rate to 0.23 ‰.

And (3) testing a bonding wire: the intelligent card carrier band blind hole is used for bridging the chip and the band base and playing a role in transmitting electric signals, one of important performance indexes is a gold wire bonding wire which is characterized by a tensile value.

In the test, a wire bonding machine uses a Shinkawa wire bonding machine in Japan, a gold wire uses a smoke bench to attract gold to obtain a 25 mu m gold wire, the wire bonding test is carried out on the plated blind holes, the tensile force standard is greater than 4g, the wire bonding machine is judged to be NG when the tensile force value is less than 4g, and the statistical result is as follows:

item	Example 1	Example 2	Example 3	Comparative example 1	Comparative example 2
						Number of bonding wires	100	100	100	100	100
Number of tension NG	0	0	0	0	21
						Percent defective	0%	0%	0%	0%	21%

The test results show that the bonding wires of examples 1-3 and comparative example 1 all passed, no NG appeared, and comparative example 2 had a wire bonding failure rate of 21% due to the addition of the chemical wetting agent.

Of course, the foregoing is only a preferred embodiment of the invention and should not be taken as limiting the scope of the embodiments of the invention. The present invention is not limited to the above examples, and equivalent changes and modifications made by those skilled in the art within the spirit and scope of the present invention should be construed as being included in the scope of the present invention.

Claims

1. A smart card carrier band blind hole electroplating method is to electroplate after carrier band pretreatment, and is characterized in that: before the carrier band enters an electroplating bath for electroplating, firstly, carrying out infiltration pretreatment on the blind hole area of the carrier band by adopting a plating solution in the electroplating bath through dynamic spraying, and then, entering the treated carrier band into the electroplating bath for electroplating;

the jet flow of the power spray is 10-100L/min;

the spraying pressure of the power spraying is 1-20 bar.

2. The blind hole electroplating method for the smart card carrier tape according to claim 1, wherein the blind hole electroplating method comprises the following steps: the temperature of the plating solution in the plating bath is 30-70 ℃.

3. The blind hole electroplating method for the smart card carrier tape according to claim 1, wherein the blind hole electroplating method comprises the following steps: the carrier tape pretreatment is to carry out deoiling treatment on the carrier tape and then carry out activation treatment.

4. The blind hole electroplating method for the smart card carrier tape according to claim 3, wherein the blind hole electroplating method comprises the following steps: the degreasing treatment adopts ultrasonic and cathode electrolysis degreasing, hot alkali degreasing or degreasing powder degreasing processes.

5. The blind hole electroplating method for the smart card carrier tape according to claim 3, wherein the blind hole electroplating method comprises the following steps: the activation treatment is to carry out acid cleaning on the surface of the carrier tape by adopting acid or activated salt.