WO2016023162A1

WO2016023162A1 - Electroplating tank and electroplating device

Info

Publication number: WO2016023162A1
Application number: PCT/CN2014/084122
Authority: WO
Inventors: 朱拓; 姜雪飞; 韩焱林; 田小刚
Original assignee: 深圳崇达多层线路板有限公司
Priority date: 2014-08-11
Filing date: 2014-08-11
Publication date: 2016-02-18
Also published as: CN104302815A

Abstract

Provided are an electroplating tank and an electroplating device using the electroplating tank, wherein the electroplating tank comprises a tank body in which a wall anode is provided respectively on the two opposite tank walls, at least one interval anode is provided between the two wall anodes, and the wall anodes and interval anodes are equidistantly distributed inside the tank; the interval anodes divide the tank body into at least two tank positions, and the various tank positions are in communication with one another below the interval anodes; and the interval anode is composed of an insulating plate and single anodes respectively disposed on the two faces of the insulating plate. By providing the interval anodes in the electroplating tank, a relatively independent electric field is formed in each tank position, which avoids a cross influence of electric currents of the two cylinder bodies. Gaps are reserved between the interval anode and the bottom of the tank body such that electroplate liquids in the various tank bodies can be in communication. By a cooperation of the interval anodes and a circulating filtration mechanism, the electroplate liquids can be sufficiently mixed, maintain homogeneity for a long time, and also cannot affect the stability of the electroplating environment, so as to improve the homogeneity of a plated layer.

Description

Description: A plating bath and plating device

The present invention relates to the field of electroplating technology, and in particular, to an electroplating bath and a plating apparatus.

Background technique

A printed circuit board is a support for electronic components that provides electrical connections to electronic components. The production process of printed circuit board is generally as follows: material opening → inner layer pattern transfer - inner layer etching → lamination → drilling → copper sinking → plate power → outer layer pattern transfer → etching → solder mask → surface treatment → molding processing . The printed circuit board is usually plated with nickel gold or chemical nickel gold in the surface treatment.

One of the biggest advantages of chemical nickel gold is that the process is relatively simple, using only two key chemical syrups, namely electroless plating solutions containing hypophosphite and nickel salts and acidic gold water. The process is generally acid-washed, micro-etched, activated, electroless nickel-plated, cleaned, immersed in gold, etc. The key step is autocatalytic electroless nickel plating on the copper pad to control the nickel plating by controlling parameters such as time and temperature and pH. Thickness; Reusing the activity of the plated nickel, immersing the nickel-plated pad in acidic gold water, replacing the gold from the solution to the surface of the pad by a chemical displacement reaction, and partially depositing nickel into the gold water, When the displaced gold completely covers the nickel layer, the displacement reaction is automatically stopped, and then the dirt on the surface of the pad is cleaned to complete the chemical nickel gold process.

Electroplated nickel gold is applied by applying a layer of low-stress nickel on the copper substrate of the pad, and then plating a thin layer of gold on the nickel. By controlling the plating time in a certain case of the plating solution To achieve control of the thickness of the coating. Other process steps such as cleaning and micro-etching are basically the same as those of chemical nickel gold.

Whether it is chemical nickel gold or electroplated nickel gold, it is necessary to pay attention to the coating properties, hardness, structure and solderability. For the existing electroplated nickel gold process, the common problem is that the uniformity of the coating cannot reach more than 90%, and it is difficult to meet the requirements of product quality (the detection method of uniformity is: on the PCB board) Open several equal-sized PADs and perform electroplated nickel-gold treatment in the normal process, and then measure the thickness of the nickel-gold plating of each PAD, using the formula (MAX-MIN) / average X 2 X 100%); The current difference between the slots in the slot is large, so that the concentration of the plating solution in the different slots is different, and the dead angle of the plating solution exists in the slot, so that the amount of gold salt consumed in the plating increases. In the electroplating process, the stability of the electroplating environment is poor, and frequent debugging is required, and the increase in the number of debugging increases the quality hazard of the product.

Summary of the invention

The invention aims at the cross-effect of the electric field in the electroplating bath, the electroplating liquid circulation effect is not good, and the plating solution is frequently debugged, which leads to the problem of poor uniformity of the plating layer, and provides a method for reducing the crossover effect of the electric field and enhancing the circulation effect of the plating solution, thereby improving the uniformity of the plating layer. a plating bath and an electroplating device using the plating bath.

In order to achieve the above object, the present invention adopts the following technical solutions.

An electroplating tank includes a tank body, wherein a wall anode is disposed on each of the two groove walls facing each other, and at least one spaced anode is disposed between the two wall anodes, and the wall anode and the spacer anode are in the tank body. Isometrically distributed; the spacer anode divides the tank body into at least two slots, and the slots are connected to each other under the interval anode; the spacer anode is composed of an insulating plate and a single anode respectively disposed on both sides of the insulating plate .

The bottom of the insulating plate protrudes from the bottom of the single anode by 10-20 cm.

The bottom end of the insulating plate is 5-15 cm away from the bottom of the trough.

Both the wall anode and the single anode are platinum titanium mesh.

Each of the slots is provided with a circulation filter mechanism.

The circulating filter mechanism comprises a liquid suction pipe, a circulating filter pump, an outlet pipe and a nozzle connected in sequence; the nozzle is arranged at the bottom of the tank, and the water inlet of the liquid pipe extends to the upper part of the tank.

The nozzle is a long tube, and the long tube is provided with two rows of injection holes.

The arc between the orifice of the orifice and the highest point of the long tube is π / 6 - π / 3. An electroplating apparatus includes an electroplating line crane, a flying bus, a plating fixture, and a plating tank, wherein each of the two groove walls facing each other in the tank has a wall anode, and the two wall anodes are disposed between At least one spacer anode, the wall anode and the spacer anode are equidistantly distributed in the tank; the spacer anode divides the tank into at least two slots, and the slots communicate with each other under the interval anode; The utility model is composed of an insulating plate and a single anode respectively disposed on both sides of the insulating plate; the plating product fixing member is connected to the flying bus, the flying cells are respectively locked in the slots, and the plating wire crane is disposed in the flying bus Above and reciprocating above the plating bath. The wall anode and the spacer anode are respectively electrically connected to a positive electrode of the power source; the flying bus is electrically connected to a negative electrode of the power source.

Preferably, both ends of the wall anode and the spacer anode are electrically connected to the positive pole of the power source; both ends of the flying battery are electrically connected to the negative pole of the power source.

The plate fixing member is a fixing clip, and the fixing clip is fixedly connected with the flying bag.

Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a spacer anode composed of a single anode, an insulating plate and a single anode in a plating bath, so that two single anodes in one spacer anode are respectively It is located in two different slots, thus forming a relatively independent electric field, which does not affect each other, avoiding the crossover effect of the two cylinder currents. A gap is reserved between the spacer anode and the bottom of the tank body, so that the plating liquid in each tank can flow through each other; and the gap between the gap anode and the bottom of the tank body is set to 5-15 cm, so that the degree of circulation exchange of the plating solution can be made. Most suitable. At the lower end of the spacer anode, the insulating plate protrudes from a single anode by 10-20 cm, so that the single anode can be more easily and accurately fixed on the insulating plate. A circulating filter mechanism is arranged in each slot, and two rows of nozzle holes are arranged on the nozzle of the circulation filter mechanism, which can improve the circulation effect of the plating solution, and make the plating solution in each slot better; The injection pressure and the spray direction of the liquid are set at π /6-π / 3 radians from the highest point of the nozzle to obtain the best cycle effect. The plating tank of the present invention and the plating apparatus using the plating tank can fully mix the plating solution by mixing the anode and the circulation filter mechanism, and maintain uniformity for a long time without affecting the stability of the plating environment, thereby improving Plating Uniformity, the coating uniformity of all plating products is more than 90%.

DRAWINGS

1 is a schematic structural view of a plating tank according to Embodiment 1 of the present invention;

1 is a plan view of a plating bath according to Embodiment 1 of the present invention;

Figure 3 is a cross-sectional view showing a plating tank according to Embodiment 1 of the present invention;

Figure 4 is a schematic cross-sectional view showing a plating bath (electroplating process) in Embodiment 1 of the present invention;

Figure 5 is a schematic structural view of a plating apparatus according to Embodiment 1 of the present invention;

Fig. 6 is a cross-sectional view showing a plating tank in Comparative Example 2.

detailed description

In order to more fully understand the technical content of the present invention, the technical solutions of the present invention will be further described and illustrated in conjunction with the specific embodiments.

Example 1

1-3, a plating tank 10 is provided in the embodiment, including a tank body, a wall anode 12, a single anode 15, an insulating plate 14, a circulating filter pump 16, a liquid suction pipe 11, an outlet pipe 17, and a nozzle. 19. The insulating plate 14 is a PP insulating plate, and a single anode 15 is fixed on two planes of the PP insulating plate, and the bottom of the PP insulating plate protrudes from the bottom edge of the single anode 15 by 15 cm, a single anode 15, a PP insulating plate, The single anodes 15 are sequentially stacked to form a spacer anode. Further, the nozzle 19 is a long pipe, and the liquid suction pipe 11, the circulation filter pump 16, the discharge pipe 17, and the nozzle 19 are sequentially connected to constitute a circulation filtering mechanism. The wall anode 12 and the single anode 15 are both platinum titanium mesh.

The trough body is a square trough, and a wall surface anode 12 is respectively disposed on the two groove walls facing each other in the tank body, and a spacer anode is fixed in the middle of the two wall surface anodes 12, and the distance between the gap anode and the two wall surface anodes 12 is equal. And one end of the two wall anode 12 and one end of the spacer anode are respectively electrically connected to the positive pole of the power source, and the bottom end of the spacer anode is 10 cm away from the bottom of the tank body, so that a gap between the anode and the bottom of the tank body is formed. A gap. The groove between the wall anode 12 and the spacer anode serves as a slot 18, and the two slots 18 communicate with each other through the gap at the bottom of the spacer anode. A hanging position 13 for fixing the flying bay is respectively disposed at both ends of each slot 18. In addition, each of the slots 18 is provided with a circulating filter mechanism, that is, the water inlet of the liquid pipe 1 1 extends to the upper portion of the tank 18, and the other end of the liquid pipe 1 1 is connected to the circulating filter pump 16, the circulating filter pump 16 is connected to one end of the discharge pipe 17, and the other end of the discharge pipe 17 is connected to the nozzle 19. The nozzle 19 is disposed in the middle of the bottom of the groove 18, and two rows of nozzle holes 191 are disposed on the nozzle 19 at a maximum point of π /4 (radian) from the nozzle 19, so that the spray direction and the vertical direction of the nozzle hole 191 are provided. The angle between them is 45°.

Referring to Fig. 4, a plating apparatus is composed of the above-described plating tank 10, flying bus 20, and plating line crane 30. A plurality of plating fixtures 21 are fixedly coupled to the flying mat 20, and the plating fixtures 21 are fixing clips. The flying bus 20 is hung above the plating tank 10 through the hanging position 1 3 on the plating tank 10, and one end of the flying bus is electrically connected to the negative pole of the power source. The electroplating line crane 30 is disposed above the flying bus 20 and is reciprocally movable above the plating tank 10.

The PCB is electroplated with nickel gold using this plating apparatus.

Nickel plating: First, the nickel plating solution is introduced into the plating bath 1 G, and then the PCB 40 is clamped by the fixing clips in the flying bus 20 (the PCB 40 has been subjected to pre-treatment such as degreasing, water washing, etching, washing, activation, etc.) And moving the flying bus 20 to the plating tank 10 through the electroplating line crane 30, so that the flying bus 20 is hung on the hanging position 13 of the plating tank 10, and the PCB 40 fixed by the fixing clip is immersed in the nickel plating solution. In, as shown in Figure 5. The circulation filter mechanism is opened, and the liquid suction tube 11 sucks the nickel plating solution in the upper portion of the tank 18, filters through the circulation filter pump 16, flows through the liquid outlet pipe 17 and enters the nozzle 19, and finally is sprayed back into the groove through the nozzle hole in the nozzle 19. In position 18, it is thoroughly mixed with the nickel plating solution in the tank 18. The discharge direction of the nickel plating solution is 45° to the vertical direction. Then, the positive poles of the power source are respectively connected to the wall anode 12 and the spacer anode, and the negative poles of the power source are respectively connected to the PCB 40, so that the PCB 40 becomes a cathode and nickel plating starts. After the nickel plating process is completed, the flying bus 20 is lifted by the plating line crane 30, thereby removing the PCB 40 from the plating tank 10. Nickel plating solution: Ni ²⁺ 65-75g / L, N iC l ₂ 1 0- 30g / L, H ₃ B0 ₃ 39-45g / L, pH = 3. 8-4. 4 ₀ electroplating gold: has been carried out The nickel-plated PCB is sequentially washed, activated, and washed with water, and then the PCB is transferred into a plating bath containing a gold plating solution in the same manner as in the case of electroplating nickel, so that the PCB is completely immersed in the gold plating solution. The circulation filter mechanism is opened, and the liquid extraction tube sucks the gold plating solution on the upper part of the tank, filters through the circulating filter pump, flows through the liquid outlet pipe and enters the nozzle, and finally is sprayed back into the groove by the nozzle hole in the nozzle, and the groove position The gold plating solution in the mixture is thoroughly mixed. The gold plating solution is ejected at a 45° angle to the vertical. Then, the positive pole of the power supply is respectively connected to the wall anode and the spacer anode, and the negative pole of the power source is respectively connected with the PCB, so that the PCB becomes the cathode and the gold plating starts. After the gold plating process is completed, the flying bus is lifted by the plating line crane to remove the PCB from the plating tank. Then, the PCB is subjected to a subsequent process such as water washing and DI watering, and dried to complete the electroplating nickel gold treatment of the PCB. The PCB treated with electroplated nickel gold is denoted as B1.

Gold plating solution: gold content of 2 6g / L, N i ²⁺ 200ppm, Cu ²⁺ 20ppm, pH 4. 6-4. 8, specific gravity 1. 09-1. 14, temperature 33- 37 °C.

Example 2

The plating bath of this embodiment is substantially the same as the plating bath of Example 1, except that the bottom end of the spacer is 15 cm away from the bottom of the bath.

The plating apparatus of this embodiment is basically the same as the plating apparatus of the first embodiment except that the plating tank in the plating apparatus of the first embodiment is replaced with the plating tank of this embodiment.

The PCB was subjected to electroplating nickel gold treatment as in the electroplated nickel gold method described in Example 1. The electroplated nickel-plated PCB is labeled B2.

Example 3

The plating bath of this embodiment is substantially the same as the plating bath of Embodiment 1, except that the bottom end of the spacer anode is 5 cm away from the bottom of the bath body.

The plating apparatus of this embodiment is basically the same as the plating apparatus of Embodiment 1, except that: The plating bath in the plating apparatus of Embodiment 1 was replaced with the plating tank of this embodiment.

The PCB was subjected to electroplating nickel gold treatment as in the electroplated nickel gold method described in Example 1. The electroplated nickel-plated PCB is labeled B 3 .

Example 4

The plating bath of this embodiment is substantially the same as the plating bath of Embodiment 1, except that: on the nozzle, the orifice is located at a distance of π / 3 (radian) from the highest point of the nozzle.

The PCB was subjected to electroplating nickel gold treatment as in the electroplated nickel gold method described in Example 1. The electroplated nickel-plated PCB is denoted as Β4.

Example 5

The plating bath of this embodiment is substantially the same as the plating bath of Embodiment 1, except that: on the nozzle, the orifice is located at a distance of π / 6 (radian) from the highest point of the nozzle.

The PCB was subjected to electroplating nickel gold treatment as in the electroplated nickel gold method described in Example 1. The electroplated nickel-plated PCB is denoted as Β5.

Example 6

The plating bath of this embodiment is substantially the same as the plating bath of the embodiment 1, except that both ends of the two-wall anode and the two ends of the spacer anode are electrically connected to the positive electrode of the power source, respectively.

The electroplating apparatus of this embodiment is basically the same as the electroplating apparatus of the first embodiment, except that: the electroplating bath in the electroplating apparatus of the embodiment 1 is replaced with the electroplating bath of the embodiment, and the two ends of the Tianba are respectively connected to the power source. The negative electrode is electrically connected. The PCB was subjected to electroplating nickel gold treatment as in the electroplated nickel gold method described in Example 1. The PCB treated with electroplated nickel gold is denoted as B6.

In other embodiments, the insulating sheets constituting the spacer anode may use other insulating sheets in addition to the PP insulating sheets. Moreover, three or more spaced anodes may be disposed in the tank according to design requirements, and the spacing anodes are equally spaced between the two wall anodes, that is, the distance between the wall anode and the adjacent spacer anode is equal to two adjacent intervals. The distance between the anodes. Two nozzles or more nozzles can be placed at the bottom of each slot depending on the size of the slot. In addition, in the spacer anode, it is also possible to provide the bottom of the PP insulating plate to protrude from the bottom edge of the single anode 10-20 cm _o

Comparative example 1

The plating bath of this comparative example was substantially the same as the plating bath of Example 1, except that the bottom end of the spacer anode was spaced 20 cm from the bottom of the tank.

The PCB was subjected to electroplating nickel gold treatment as in the electroplated nickel gold method described in Example 1. The electroplated nickel-plated PCB is labeled B7.

Comparative example 2

A plating tank, as shown in FIG. 6, includes a square groove body, and a platinum titanium mesh is fixed as an anode on each of the two groove walls facing each other in the tank body, and a platinum titanium mesh is disposed as an anode in the middle of the tank body. Three platinum titanium meshes divide the tank into two slots, and the two slots communicate through the gap in the middle of the intermediate platinum titanium mesh. A circulating filter mechanism is disposed in the tank body, and the circulating filter mechanism is composed of a liquid pipe connected in sequence, a circulating filter pump, an outlet pipe and two nozzles. The two nozzles are respectively arranged at the bottom of the two slots, and the water inlet of the suction pipe extends to the upper part of one of the slots. A row of injection holes is arranged on the nozzle and at the highest point of the nozzle. The plating apparatus of this comparative example was basically the same as the plating apparatus of Example 1, except that the plating tank in the plating apparatus of Example 1 was replaced with the plating tank of this example.

The PCB was subjected to electroplating nickel gold treatment as in the electroplated nickel gold method described in Example 1. The electroplated nickel-plated PCB is labeled B8.

Production was carried out according to Examples 1-5 and Comparative 1-2, respectively, and the production area per day was 60 m7d. The plating effects of Examples 1-5 and Comparative 1-2 treated PCBs (B1-B7) are shown in the table below.

In the above table, "the uniformity of the two slots is extremely poor" means that the plating uniformity of the two slots of the same board is the greatest difference. The test method for plating uniformity is as follows: The thickness of the nickel-gold plating at various positions (9 places) on the PCB is measured, and then calculated by the formula (MAX-MIN) / average value X 2 00%.

The above description is only for the purpose of further illustrating the technical content of the present invention in order to facilitate the understanding of the reader, but the embodiment of the present invention is not limited thereto, and any technology extension or re-creation according to the present invention is subject to Protection of the invention.

Claims

Claim

A plating tank, comprising a tank body, wherein: a wall anode is disposed on each of the two groove walls facing each other, and at least one spacer anode is disposed between the two wall anodes, the wall anode The spacer anode is equidistantly distributed in the tank body; the spacer anode divides the tank body into at least two slots, and the slots are connected to each other under the interval anode; the spacer anode is provided by an insulating plate and respectively disposed in the insulation The single anode consists of two sides of the board.

2. A plating bath according to claim 1, wherein: the bottom of the insulating plate protrudes from the bottom of the single anode by 10-20 cm.

3, an electroplating tank according to the claim 2, wherein: said bottom end of the tank bottom insulating plate apart 5-15cm ₀

4. A plating bath according to claim 3, wherein: said wall anode and said single anode are both platinum titanium mesh.

5. The electroplating bath according to claim 1, wherein: each of the slots is provided with a circulating filter mechanism.

6. The electroplating bath according to claim 5, wherein: the circulating filter mechanism comprises a pumping pipe, a circulating filter pump, an outlet pipe and a nozzle connected in sequence; the nozzle is arranged in the slot At the bottom, the water inlet of the liquid pipe extends to the upper portion of the tank.

7. The electroplating bath according to claim 6, wherein: the nozzle is a long tube, and the long tube is provided with two rows of nozzle holes.

8. A plating bath according to claim 7, wherein: the arc between the orifice of the orifice and the highest point of the long tube is π / 6 - π / 3.

9. An electroplating apparatus comprising a plating line crane, a flying bus, a plating fixture and a plating tank, characterized in that: a wall surface anode is disposed on each of the opposing groove walls of the plating tank, and at least one spaced anode is disposed between the two wall anodes, and the wall anode and the spacer anode are equidistantly distributed in the tank body; The anode divides the tank into at least two slots, and the slots communicate with each other under the interval anode; the spacer anode is composed of an insulating plate and a single anode respectively disposed on both sides of the insulating plate;

The plating fixture is connected to the flying bay, and the flying bay is respectively disposed in the slot, the plating trolley is disposed above the flying pascal and can reciprocate above the plating tank; the anode and the spacing of the wall The anodes are electrically connected to the positive poles of the power source, respectively; the flying cells are electrically connected to the negative pole of the power source.

10. A plating apparatus according to claim 9, wherein: both ends of the wall anode and the spacer anode are electrically connected to a positive electrode of the power source; both ends of the flying bus are electrically connected to a negative electrode of the power source.