KR20190083041A - Manufacturing Method of mixed metal oxide electrode for PCB - Google Patents

Abstract

The present invention relates to a manufacturing method of a metal oxide anode for PCB electrolytic copper plating to reduce the consumption of organic additives in an electroplating process and to extend the life and improve the performance. The manufacturing method of a metal oxide anode for PCB electrolytic copper plating, in manufacturing the anode of an electrolysis device, comprises a pre-treatment step of subjecting the surface of a titanium base material to multiple blasting but changing a blasting ball size to form a surface with varying degrees of roughness, and a step of forming a mixed metal oxide coating layer (MMO) having a different mixed composition ratio of a catalyst coating layer on the pretreated titanium base material, wherein a heat treatment temperature is changed when the mixed metal oxide coating layer is formed.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a metal oxide anode for PCB electrolytic copper plating,

The present invention relates to a method for manufacturing a metal oxide anode for PCB electrolytic copper plating in which consumption of an organic additive in an electrolytic plating process is reduced, life is extended and performance is improved.

In general, development of products with high functionality and portability is proceeding actively through PCB multi-layering due to growth and speeding up and miniaturization of electronic industry such as smart phones and tablet PCs. One of the important techniques is to process each layer of via-hole for PCB multi-layering and to fill the hole by via-filing plating to form electrical path. The via hole method, which serves as an electrical pathway for multilayering, has the advantage that the loss and short of signals can be reduced as well as the volume when compared with the conventional wire bonding method.

And the copper filling through electrolytic plating is required to fill conductive material inside the via hole of PCB, so that it can serve as an electrical path in the multilayer substrate. At this time, aluminum (Al) has been used as a conductive material in the past, but copper (Cu) is mainly used now. Copper has been studied as a fill metal for three-dimensional high-density packaging due to its relatively good electrical properties and high resistance to electromigration. Methods for filling copper include physical vapor deposition (PVD), electroless plating, and electrolytic plating.

Although the Singi PVD process has the merit of obtaining a simple and high purity film, the mean free path of metal atoms or clusters becomes longer due to the high vacuum during deposition, and atomic ions are adsorbed directly on the substrate, The sticking coefficient is high. In addition, because the deposition temperature is low, the moving speed of the deposited atoms is slow, and the deposits are obscured from the incident angle, or the film is hardly deposited on the plane parallel to the incident angle. Thus, It is difficult to obtain a degree of coverage, which results in poor coverage of the layer.

The electroless plating method is a method of filling copper on the surface of the substrate through an oxidation-reduction reaction between a reducing agent and a copper ion applied to a solution. This method does not require external transfer and can form a uniform copper layer irrespective of the type of the substrate, which is widely used for forming a seed layer for electroplating, but with a low productivity due to a relatively low deposition rate, But is not applied to the post-formation process.

Since the electrolytic plating method can quickly and uniformly produce a thin film having excellent characteristics, it is highly reliable and low in process cost, and is easily used in mass production, and thus is widely used. The electrolytic plating method is a process for forming a thin metal film on the surface of a negative electrode by causing positive ions (positive electrode and negative electrode) to be inserted into a solution containing metal ions and reducing the metal ions at the negative electrode by applying current, Electrochemical reduction is accomplished through the following reaction.

Cu ²⁺ (aq) + 2e ^- ? Cu (s)

In order to improve the plating performance, it is required to increase the diameter of the via hole gradually and the aspect ratio to increase due to the high-leveling of the PCB, so that the diffusion of copper ions into the via becomes difficult and the inside of the via is slowly plated do. As a result, defects such as voids or seams are generated.

Therefore, for defect-free via-filling, bottom-up charging must be performed from the bottom of the via-hole to the entrance side of the via hole when the electrolytic plating is performed. For the bottom-up charging, the organic additive (inhibitor) Brighteners, Levelers) are important. The reason why they are noticed is that they can improve the microstructure change such as grain growth mechanism, crystallinity structure and surface roughness, and can change physical properties of the plated metal depending on additive composition and concentration This is possible.

The brightener is adsorbed on the surface of the substrate and serves as a catalyst for increasing the nucleation water of copper during the reduction of copper ions, thereby accelerating the copper plating rate. Therefore, when the polishing agent is adsorbed on the bottom of the via hole, defect-free copper charging can occur, which depends on the concentration of the polishing agent and the stirring speed.

The inhibitor is an organic material used for lowering a plating rate at the time of electroplating, and is adsorbed on a substrate to form a passivation layer to suppress plating.

The leveler is an additive which is present in the protruding part or corner part of the surface of the substrate plating layer and partially suppresses the plating, thereby making the thickness of the plating uniform regardless of the structure of the surface to be plated.

Therefore, it is also important to achieve high filling performance in order to reduce plating time as well as defect-free via-filling. In order to achieve a high filling performance, the stirring-dependent adsorption of the additive should be strengthened. The stirring-dependent adsorption phenomenon means that the adsorption of the additive is affected by the intensity of the stirring. As the stirring speed is higher, the adsorption of the additive that suppresses the reduction of copper at the inlet of the via is increased and the plating rate is decreased. The weak via bottoms are less susceptible to copper reduction, resulting in faster plating rates.

However, the problem that arises when electrolytic plating occurs is that the metal ions in the electrolytic solution migrate to the cathode due to the current applied during the electrolytic plating, and the anions such as OH ^- or SO ₄ ^2- are oxidized Oxygen is generated. However, the organic additives which are vulnerable to oxidation are also contained in the electrolytic solution, and as the characteristics of the organic additives are weakened or deteriorated during the anodic oxidation reaction, the cost of the plating solution is increased and the possibility of defects in the via- Resulting in a problem of low reliability.

Several solutions have been proposed to solve the above problems. For example, Korean Patent Laid-Open Publication No. 2001-0069918 discloses an apparatus in which a membrane is provided in the vicinity of an anode for blocking contact between an additive and an anode. However, there is a disadvantage in that additional cost is incurred when using an expensive membrane and maintenance is required.

In addition, PCT / EP2003 / 014785 invented a cathode having a mesh-type shield attached to reduce mass transfer. However, this also limits the need for continuous management as the plating sludge is attached to the mesh.

There is a limit to reducing the consumption of additives in the electrolytic solution due to the addition / modification of the device, and therefore, a solution that can be fundamentally solved is needed.

In general, the anode manufacturing process includes four steps of pretreatment to form a titanium base material capable of supporting a metal oxide, applying each kind of metal oxide to the upper portion of the titanium base material, By repeating the heat treatment process, it is possible to perform a function as an electrically active catalyst. Here, the four-step pretreatment process generally refers to a degreasing-blasting-acid etching-water washing process. In the degreasing and acid etching processes, organic solvents such as acetone and IPA and acidic solutions such as hydrochloric acid, sulfuric acid and oxalic acid are used. Removal of oil through degreasing and etching to remove impurities from the base metal and increase the surface stability are required. However, a large amount of chemical products are required in the mass production process, thereby increasing the time required for the operation, toxic gases generated during the operation, There is a disadvantage in that time and economic losses are caused due to the generated waste liquid.

KR 10-1008899 KR 10-1595625 KR 10-1665754 KR 10-0931095 (Patent Publication No. 0005) KR 10-2001-0069918 PCT / EP2003 / 014785

The present invention has been devised in order to solve these problems, and it is an object of the present invention to provide a method and apparatus for pretreating a titanium base material in two stages except for the degreasing and acid etching processes in the existing four stages, Sandblasting of blast ball size is carried out in multiple stages to completely remove oil components that may remain in the titanium base material and replace the fine roughness formed by the acid etching process with double sand blasting, Although the microstructures that can not be formed are formed through the microblasting ball and the surface roughness is increased, the organic electrolytic plating process reduces the consumption of organic additives, prolongs the service life and improves the performance of the electrolytic plating process, To provide a positive electrode.

That is, the present invention relates to an organic solvent such as ethanol, isopropyl alcohol, and acetone, which is a conventional chemical treatment compound, and an organic solvent such as hydrochloric acid, sulfuric acid, A metal oxide anode for PCB electrolytic copper plating is produced without any acid etching solution such as oxalic acid.

The present invention relates to a method of manufacturing an anode of an electrolytic apparatus, comprising: a pretreatment step of performing multiple blast treatment on the surface of a titanium base material to form a surface roughness having different roughness by varying a blast ball size; Forming a mixed metal oxide (MMO) layer having different mixed composition ratios; and forming a composite metal oxide coating layer on the metal oxide layer by a heat treatment at a different temperature. .

Wherein the anode coating material has a basic molar composition of AxByCz and x + y + z = 100, wherein A and B are platinum group metals, and C is a valve metal, and each of the coating layers is coated with a solution having different contents, Structure of the present invention.

The sandblasting ball size change is changed little by little to five times and is subjected to multiple pretreatment to increase the blasting roughness and to enlarge the surface area.

The blasting ball size is characterized in that it is treated in the first stage of sandblasting to less than 16 meshes and less than 46 meshes and is preliminarily treated with a mesh having a blast ball size of 20% to 80%.

The coating of the metal oxide is performed four to 25 times, the heat treatment is performed at a temperature of 350 to 600 ° C., and the sintering is performed at a temperature of 10 to 60 minutes.

In the present invention, a metal oxide anode for PCB electrolytic copper plating is pretreated with multiple sand blasting and water washing only without chemical treatment, thereby forming an environmentally-friendly and wide surface roughness, thereby improving the primary performance of the composite metal oxide. (MMO) anode with improved lifetime and reduced consumption of organic additives by applying a multi-coating layer having different composition and heat treatment temperature, the anode replacement cycle and the organic additive And prolonging further injection, thereby contributing greatly to the electrolytic plating industry.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exemplary schematic diagram showing the structure of a metal oxide anode for PCB electroplating copper plating according to the present invention;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The present invention provides a metal oxide anode for PCB electrolytic copper plating with enhanced surface area by performing multiple sandblasting treatment on a titanium base material and a high efficiency and eco-friendly pretreatment process which does not use organic solvents and acidic solutions.

The pretreatment of the titanium base material according to the present invention is performed by varying the blast ball size on the surface of the titanium base metal material to effect solid blending between the titanium base material and the coating material and physically injecting the alumina and ceramic fine particles at high pressure And sandblasting for roughening the surface of the base material is multi-processed so that surface roughness of different roughness can be formed.

Preferably, the multiple sandblasting is performed by a secondary to a fifth blasting. In the primary sandblasting step, a ball of a size of 16 mesh or less and a size of less than 46 mesh is sprayed at high pressure onto the metal surface of the base metal And then gradually blasted using a mesh having a blast ball size of 20% to 80%. In the final sand blasting treatment, a goldsmelt having a size of 46 mesh or more and a size of less than 120 mesh on the surface of the titanium base material is subjected to high- So that surface roughness having different roughness is formed on the titanium base material by means of spraying and giving additional roughness.

The metal oxide anode for PCB electrolytic copper plating according to the present invention comprises a lower coating layer 2 and an upper coating layer 3 on the upper surface of the substrate 1 as shown in FIG.

As described above, the metal surface of the titanium base material subjected to the multiple sandblasting generally has a larger surface area than that of the titanium base material subjected to the single blasting, so that micro-roughness can be obtained without performing chemical treatment through acid etching. In addition, it is possible to produce environmentally friendly products that do not generate waste solutions due to no chemical treatment.

In addition, in the anode coating of the composite metal oxide (MMO), the composite metal oxide supported on the titanium base material having the surface roughness of different roughness by being pretreated by the above-mentioned multiple sandblasting has high electric conductivity and electrocatalytic activity Applying a catalyst coating layer which makes the electrolytic reaction sustainable, it is possible to reduce the durability of the anode and reduce the consumption of the polish, and improve the performance of the anode by applying multiple coatings in which the composition ratio of the mixed metal material and the heat treatment temperature are changed so as to reduce the consumption of the organic additives. .

When the metal oxide is coated, the number of times of coating is preferably from 4 times to at most 25 times or less. This is because when the coating is performed less than 4 times, the durability is poor and when the coating is carried out more than 25 times, This is because the economy is less competitive.

When the metal oxide is coated, the heat treatment temperature is preferably in the range of 350 ° C. to 600 ° C., which is lower than the temperature of the electric furnace, depending on the composition of the coating solution. May be present in the form of oxides, whereas if calcined above 600 ° C, changes in the physical properties of the metal oxides may occur and the cost of the anode production may increase.

It is preferable that the calcination time is less than 10 minutes and longer than 60 minutes according to the composition of the coating solution when the metal oxide is coated. This is because the calcination time is economical and the durability of the cathode and the performance . ≪ / RTI >

Wherein the anode coating material has a basic molar composition of AxByCz and x + y + z = 100, wherein A and B are platinum group metals, and C is a valve metal and is coated with a solution having a different content of each coating layer So that the performance of the anode can be improved by the multi-layered coating layer.

(1) Primary sandblasting treatment

50 mm x 100 mm x 1 t Gr.1 Titanium base material was sprayed with high pressure at 24 mesh meshes to give surface roughness to the surface of titanium base material.

(2) Secondary sandblasting treatment

The surface of the primary sandblasted titanium base material is subjected to a secondary sandblasting process in which impurities are removed through an air compressor and then sprayed with 80 mesh meshes on the surface of the titanium base material. And a surface roughness having a roughness level of +/- 1.0 mu m was generated.

The secondary sandblasted titanium base material was washed with water and dried at room temperature for 10 minutes and then at 80 占 폚 for 30 minutes to remove water.

(3) catalyst preparation and coating process

The following catalyst preparation and coating processes were performed on the titanium base material pretreated with the sandblasting to form an active catalyst layer.

A single metal solution was prepared by dissolving iridium chloride (IrCl ₄ ) and tantalum chloride (TaCl ₅ ) in ethanol and a small amount of hydrochloric acid for one day. A small amount of a tantalum metal solution was injected into the iridium metal solution, After the metal solution was prepared, it was stirred again for one day. At this time, the molar ratio of Ir: Ta was 85:15, and the mixed metal concentration was 50 g / L based on pure metal.

Ir: Ta = 85: 15 was applied once to the top of the titanium base material pretreated with the sandblasting by brush coating, dried at room temperature for 10 minutes, dried at 80 ° C for 10 minutes, and then heat treated at 420 ° C for 30 minutes. The coating process was repeated 8 times to prepare a mixed metal oxide MMO anode.

(1) Primary sandblasting treatment

50mm X 100mmX 1t Gr.1 Titanium base material was sprayed with high pressure at 24 mesh meshes to give surface roughness to the surface of titanium base material

(2) Secondary sandblasting treatment

The surface of the primary sandblasted titanium base material is subjected to secondary sand blasting in which impurities are removed through an air compressor and then sprayed with 80 mesh meshes on the surface of the titanium base material. Lt; RTI ID = 0.0 > um. ≪ / RTI >

The secondary sandblasted titanium base material was washed with water and dried at room temperature for 10 minutes and then at 80 占 폚 for 30 minutes to remove water.

(3) catalyst preparation and coating process

The following catalyst preparation and coating processes were performed on the titanium base material pretreated with the sandblasting to form an active catalyst layer.

A single metal solution was prepared by dissolving iridium chloride (IrCl ₄ ) and tantalum chloride (TaCl ₅ ) in ethanol and a small amount of hydrochloric acid for one day. A small amount of a tantalum metal solution was injected into the iridium metal solution, After the metal solution was prepared, it was stirred again for one day. At this time, the molar ratio of Ir: Ta was 85:15, and the mixed metal concentration was 50 g / L based on pure metal.

Ir: Ta = 85: 15 was applied once to the upper part of the titanium base material pretreated with the sandblasting by brush coating, dried at room temperature for 10 minutes, dried at 80 ° C for 10 minutes, and then heat treated at 420 ° C for 30 minutes. The coating process was repeated 7 times to prepare a primary coated mixed metal oxide MMO anode.

(4) Secondary catalyst preparation and coating process

(Hereinafter referred to as " inner coating layer ") was formed on the upper surface of the titanium base material as described above, and a mixture of the same metal and mixed metal as that of the catalyst was used, The metal solution was applied to the upper portion of the inner catalyst layer three times, followed by drying in the same manner as in Example 1, followed by a heat treatment at 380 ° C for 30 minutes to form a surface coating layer to prepare a final composite metal oxide (MMO) anode.

[Comparative Example]

The Gr.1 titanium base material having a size of 50 mm X 100 mm x 1 t was ultrasonically cleaned in an acetone solution (50%) at 30 ° C for 10 minutes, and then subjected to sandblasting with a 24 mesh armor to produce a roughness of Ra = 5 ± 1.0 μm. After removing the impurities through an air compressor, the substrate was immersed in a hydrochloric acid solution (10%) at 50 ° C. and ultrasonically cleaned for 10 minutes to perform an etching process. The titanium base material was washed with water and then dried for 10 minutes at room temperature, And dried to remove water.

On the surface of the pretreated titanium base material, a mixed metal oxide MMO anode was prepared by coating the same mixed metal solution of Ir: Ta = 85: 15 (50 g / L on pure metal) 8 times as in the above example for constituting the active catalyst layer.

The three kinds of samples of the complex metal oxide cathode (10mm X 10mm X 1t) by taking the respective acceleration in 1.5M sulfuric acid at 60 ℃ temperature at a current density of 3A / cm ² lifetime produced through a series of processes as described above (ALT , Accelerated Life Test).

The end of life was selected as the time point from the initial formation voltage to 5V, and the final durability life of the samples of Example 1, Example 2 and Comparative Example was 620 hours, 636 hours, and 546 hours. The detailed experimental conditions are shown in Table 1 and Table 2 below.

Item Anode size  Electrolyte Current density Temperature   Accelerated Life Evaluation 10x10mm ² x 1t 1.5 MH ₂ SO ₄ 3A / cm ²     60 ° C

In addition, consumption of the copper plating solution polishing agent was evaluated using the same metal oxide. Electrolytic copper plating reaction was carried out using two anode and one anode of Comparative Example through a CVS analyzing apparatus (Metrohm, 797 VA). The electrolytic copper plating reaction of the anode and the polish concentration in the pre-reaction copper plating solution The concentration of the polishing agent in the copper plating solution was measured and compared. The polishing agent used in the experiment was a commercial polishing agent and the initial concentration (pre-reaction concentration) was set at 1 mL / L. Detailed experimental conditions and results are shown in the table below.

As a result, the consumption rates of the brighteners of the positive and negative electrodes of Examples 1 and 2 were 27.5%, 10% and 43.9%, respectively. The detailed experimental conditions are shown in Tables 3 and 4 below.

 Item Anode size
    (Reaction area) Current Density and Plating Time Temperature   Evaluation of Polish Consumption 50x100mm ²
(50 x 50 mm ² )    1.5 ASD 10 min     22 ℃ Polishing agent consumption formula:
[Concentration of the copper plating solution before the reaction (mL / L) - Concentration of the copper plating solution after the reaction (mL / L) × 100 (%)

  Item Brightener concentration (mL / L) Consumption of Brightener (%)        Before plating reaction      0.998        -        Example 1 (after reaction)      0.724        27.5        Example 2 (after reaction)      0.898        10.0        Comparative Example (after the reaction)      0.559        43.9

The metal oxide anode prepared in Example 2 can be used as an anode for oxygen generation in various electrolytic plating processes. In particular, in the PCB electrolytic copper plating process, the consumption of organic additives is suppressed and the metal oxide anode Can be confirmed.

While the present invention has been described with reference to the exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

1: substrate
2: Lower coating layer
3: Upper coating layer

Claims (7)

In the production of the positive electrode of the electrolytic apparatus,
A pretreatment step of subjecting the surface of the titanium base material to multi-blasting to vary the blast ball size to form surface roughnesses having different roughnesses,
Forming a composite metal oxide (MMO) layer having a different composition ratio of the catalyst coating layer on the pretreated titanium base material;
Wherein the mixed metal oxide coating layer is formed at a different heat treatment temperature in forming the composite metal oxide coating layer.
The method according to claim 1,
Wherein the anode coating material has a basic molar composition of AxByCz and x + y + z = 100, wherein A and B are platinum group metals, and C is a valve metal, and each of the coating layers is coated with a solution having different contents, Wherein the metal oxide layer is formed of a coating layer of a structure of a metal oxide.
The method according to claim 1,
Wherein the sandblasting ball size change is changed from two times to five times at most, and multiple pretreatment is performed to increase the blast rugging and increase the surface area of the metal oxide anode for PCB electrolytic copper plating.
The method of claim 3,
Wherein the blast ball size is pretreated by using a mesh having a blast ball size of 20 to 80% and a size of 16 to 46 meshes in the first stage of sandblasting, A method of manufacturing an anode.
The method according to claim 1,
Wherein the metal oxide is coated four to 25 times during the coating of the metal oxide.
The method according to claim 1,
Wherein the metal oxide is baked at a temperature of 350 ° C to 600 ° C during the coating of the metal oxide.
The method according to claim 1,
Wherein the firing is performed within a range of 10 minutes to 60 minutes during the coating of the metal oxide.

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