KR20200035621A - Multi-layered metal coated super-abrasive particles and wire saw using the same - Google Patents

Abstract

The present invention relates to ultra-hard particles which can be used in a wire saw and, more specifically, to composite particles which have ferromagnetic properties while showing excellent corrosion resistance, so that electrodeposition is performed well in various electrolytes used in an electrodeposition process when manufacturing the wire saw, and are capable of improving the cutting performance of the wire saw due to excellent adhesion after electrodeposition. The composite particles according to the invention comprises ultra-hard particles and a thin film formed on surfaces of the ultra-hard particles, wherein the thin film comprises a first layer formed on the surfaces of the ultra-hard particles and consisting of a metal having ferromagnetic properties, and a second layer formed on the first layer and consisting of a metal having better corrosion resistance than the first layer.

Description

Multi-layered metal coated super-abrasive particles and wire saw using the same}

The present invention relates to a superhard particle coated with a metal or a metal compound on the surface and a method for manufacturing the same. It also relates to a wire saw comprising ultrahard particles coated on a surface of a metal or metal compound made according to the present invention.

 In the IT industry, wafers are applied in a wide variety. Silicon wafers for semiconductors, silicon wafers for photovoltaics, sapphire wafers for LEDs, and the like are typical examples. These wafers are made of thin-walled discs by slicing from silicon or sapphire single crystal ingots.

In this growing IT industry, wafers tend to become larger and thinner in order to reduce the demand for expensive wafers to secure cost competitiveness. Particularly in the semiconductor industry, the size of ingots is gradually increasing to increase productivity, and in the solar industry, attempts are being made to use thinner wafers and minimize wafer loss during processing in order to achieve cost competitiveness. In order to satisfy the demand for improving the performance of the cutting tool for slicing the ingot is increasing.

The tool used in the slicing process typically has a wire saw, which minimizes material loss during the slicing process and has a high process speed, making tool makers' new product development focused on the wire saw.

The slicing process using such a wire saw has been conventionally performed in a slurry method in which a slurry containing ultrahard particles is sprinkled around the wire, but gradually requires diamond or cBN (cubic boron nitride) directly on the wire as a demand for thin and precise slicing. Power generation is being developed as a process of slicing the wafer after attaching ultra-hard particles such as). The slicing method using the wire saw to which the ultra-hard particles are attached is rapidly increasing its application speed due to an increase in process speed, an improvement in processing precision, and an increase in yield due to a decrease in the amount of material lost during the process.

The structure of the wire saw to which the ultra-hard particles are attached has a structure in which super-hard particles (diamond, cBN, etc.) are attached to the steel wire, and these ultra-hard particles are usually attached by an electrodeposition process (electrochemical plating method). This method is to disperse the ultra-hard particles in the metal plating solution and then immerse the wire therein and proceed with electroplating, so that metal ions in the plating solution are deposited on the wire and at the same time, the ultra-hard particles are also attached to the wire. In order for the metal to precipitate and the ultrahard particles to be attached to the wire, electricity must flow through the ultrahard particles, but all of the ultrahard particles currently used do not have electrical conductivity in themselves. Therefore, the ultra-hard particles used in the electrodeposition process are applied to the wire saw manufacturing process after forming a metal layer such as nickel and cobalt on the surface for imparting conductivity during the electrodeposition process and for good adhesion in the wire after attachment.

These metal composite ultra-hard particles are mainly formed by forming a metal layer using an electroless plating process. In the actual field, the nickel metal layer is most often applied to the metal layer in consideration of corrosion resistance and price that can withstand the electrolyte used in the electrodeposition process. However, most of the formed nickel metal layer contains phosphorus, which is largely due to the effect of sodium hypophosphite used as a stable reducing agent.

U.S. Patent No. 8,858,693 discloses a composition and method for electroless nickel plating of particles, in particular, the reducing agents disclosed in the examples are all sodium hypophosphite, so the nickel metal layer must inevitably contain phosphorus in a high content. .

In addition, Korean Patent Registration No. 0545107 discloses a method of manufacturing a nickel-diamond composite powder by an electroless nickel plating method, which also requires a large amount of phosphorus because sodium hypophosphite is used as a reducing agent.

The reason for forming the nickel coating layer containing phosphorus is that it is easy to control the process using sodium hypophosphite in the process, but the corrosion resistance is improved and the adhesion with the ultra-hard particles is excellent compared to the case without phosphorus. . However, when a large amount of phosphorus is included, there is a characteristic that the ferromagnetic properties disappear.

Meanwhile, in recent years, many attempts have been made to facilitate adhesion to a wire using ferromagnetic properties as well as electrical properties by forming a ferromagnetic metal layer on a superhard particle surface according to a manufacturing process. However, the metal layer having such a ferromagnetic property has a problem in that corrosion resistance is inferior to that of a conventional metal layer having no ferromagnetic property. Accordingly, in the electrodeposition process of attaching the ultrahard particles to the wire during the wire saw manufacturing process, the metal layer having ferromagnetic properties cannot be tolerated in the electrolytic solution of the strong acid used to use the superhard particles formed on the surface of the existing non-ferromagnetic metal layer. Accordingly, in order to use the ferromagnetic properties of the powder, there is a problem in that a new electrolyte solution to be used in the electrodeposition process of the wire saw manufacturing process has to be developed.

U.S. Patent No. 8,858,693 Korea Registered Patent No. 0545107

The problem to be solved by the present invention is an ultra-hard particle that can be used in a wire saw, has ferromagnetic properties, and at the same time exhibits excellent corrosion resistance, so that electrodeposition is well performed in various electrolytes used in the electrodeposition process during wire saw production, and electrodeposition It is to provide composite particles capable of improving the cutting performance of a wire saw because of excellent adhesion, and wire saws to which these composite particles are attached.

One aspect of the present invention for solving the above problems is a composite particle comprising a superhard particle and a film formed on the surface of the superhard particle, wherein the film is formed on the superhard particle surface and has ferromagnetic properties. It is to provide a composite particle comprising a first layer made of a metal and a second layer formed of a metal formed on the first layer and having better corrosion resistance than the first layer.

Another aspect of the present invention for solving the above problems is to provide a wire saw in which the above-mentioned composite particles are attached to a wire through an electrodeposition process.

According to the present invention, the composite particles including the nickel film layer having excellent corrosion resistance as well as excellent ferromagnetic properties can be manufactured and used without limitation in a wire saw manufacturing process under various conditions.

When using the composite particles according to the present invention, in the wire saw manufacturing process using ferromagnetic properties, the electrolyte used in the electrodeposition process of the conventional wire saw manufacturing process can be used as it is, and there is no need to develop a new electrolyte, as well as various Since it can be applied to electrolytic solution conditions, it can also be usefully applied to the electrodeposition process using a new electrolytic solution.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned herein will be clearly understood by those skilled in the art from the following description.

1 is a schematic diagram of a composite particle in which a multilayer structure film of a first layer and a second layer is formed on the surface of an ultrahard particle according to the present invention.
2 is a schematic view of a composite particle in which a boundary layer, a first layer, and a second layer are sequentially formed on the surface of an ultrahard particle according to the present invention.
FIG. 3 is a photograph of the composite particles made according to Example 3, which was observed for surface through SEM after corrosion resistance test.
4 is a photograph of the composite particles made according to Comparative Example 3, which was observed through a SEM after corrosion resistance test.

Hereinafter, with reference to the accompanying drawings for the embodiment of the present invention will be described the configuration and operation. In the following description of the present invention, when it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. Also, when a part is said to 'include' a certain component, this means that other components may be further included rather than excluding other components, unless otherwise stated.

The composite particle according to the present invention is a composite particle comprising a superhard particle and a coating formed on the surface of the superhard particle, the first layer formed of a metal having ferromagnetic properties, and formed on the superhard particle surface, and It is characterized in that it comprises a second layer made of a metal formed on the first layer and having better corrosion resistance than the first layer.

Through these composite particles, in the electrodeposition process during the manufacturing process of the wire saw, it can be used in the electrolytic solution of strong acid by the second layer made of metal having excellent corrosion resistance on the surface, and at the same time, it utilizes magnetic properties by the first layer with ferromagnetic properties. You can.

Here, the ultra-hard particles may be composite particles, preferably comprising particles selected from the group consisting of diamond, cubic boron nitride, silicon carbide, boron carbide, alumina, silicon nitride, tungsten carbide, zirconia, or combinations thereof. have. In addition, even if it is not mentioned as a preferred example, particles having a certain hardness or higher that can be used for cutting or polishing applied to a wire saw can be applied without limitation.

In addition, the composite particles may include a boundary layer made of a metal having better adhesion to the ultrahard particles than the first layer between the superhard particle surface and the first layer. In particular, in the case of the nickel metal layer, it is known that when phosphorus is included, the internal stress is reduced to increase the adhesion, and since the metal layer containing nickel and phosphorus is formed in the boundary layer because it exhibits stable internal stress in the phosphorus content range of 6% by weight or more. Preferably, when the phosphorus is 10% by weight or more, since the internal stress approaches 0, it is more preferable to include nickel and phosphorus, but the content of phosphorus is 10% by weight or more. When the phosphorus content exceeds 13% by weight, the amount of sodium hypophosphite used as a reducing agent should be used in excess, which results in an increase in cost. Therefore, the boundary layer is a metal layer simultaneously containing nickel and phosphorus having high adhesion, and the content of phosphorus is preferably 6 to 13% by weight.

In the present invention, it is preferable that the first layer is a composite particle composed of a metal containing nickel and phosphorus not more than 5% by weight. When the first layer is a nickel metal layer, the ferromagnetic properties disappear as the phosphorus content increases. In general, in the industry, phosphorus content is divided into 5% by weight or less, low nickel, 6 to 9% by weight nickel, and 10 to 13% by weight nickel, which is classified as magnetic properties, electrical conductivity, and mechanical properties. You will see a lot of differences on your back. In particular, in the magnetic properties, the saturation magnetization value is the highest in the case of pure nickel without phosphorus, and then, as the amount of phosphorus added increases, the ferromagnetic properties rapidly drop from the nickel in use to produce composite particles excellent in ferromagnetic properties intended in the present invention. It is difficult to do. Therefore, the first layer is preferably formed of a pure nickel or a low nickel layer having a phosphorus content of 5% by weight or less.

In the present invention, it is preferable that the second layer is a composite particle composed of a metal containing nickel and phosphorus containing 6 to 13% by weight. The second layer acts as a protective film in various electrolytes used in the electrodeposition process during the manufacturing process of the wire saw, and the higher the phosphorus content, the higher the corrosion resistance. Therefore, it is preferable that the nickel metal layer formed of the second layer contains phosphorus or more of phosphorus. Therefore, the content of phosphorus in the nickel metal layer of the second layer is preferably 6% by weight or more and 13% by weight or less in consideration of cost increase.

In addition, the second layer may be composite particles made of a metal containing nickel and boron, because when boron is included, it has superior corrosion resistance compared to pure nickel having low ferromagnetic properties or low phosphorus nickel.

The saturation magnetization value of the composite particles provided in the present invention is preferably 3 emu / g or more. This is because, in some wire saw manufacturing lines, if it is less than 3 emu / g, it is difficult to utilize magnetic properties in the electrodeposition process.

In addition, in the present invention, the weight of the first layer exhibiting ferromagnetic properties is preferably 5 to 20% of the total weight of the composite particles. If it is less than 5%, it is difficult to impart sufficient ferromagnetic properties to the composite particles, and if it exceeds 20%, the total metal layer content becomes too large after coating to the second layer, and thus the machinability of the composite particles is poor.

In addition, in the present invention, the weight of the second layer is preferably 20-50% of the total weight of the composite particles. If it is less than 20%, it is difficult to provide sufficient corrosion resistance to the composite particles, and if it exceeds 50%, the total metal layer content included in the first layer becomes too large, resulting in poor machinability.

In addition, the weight of the boundary layer in the composite particles according to the present invention is preferably 3 to 10% of the total weight of the composite particles. This is because if the boundary layer is less than 3%, a sufficient adhesion strengthening effect cannot be seen, and if it exceeds 10%, many first and second layers that impart ferromagnetic and corrosion resistance cannot be added.

In the present invention, it is preferable that the weight of the coating is 30 to 70% of the total weight of the composite particles. If the film is less than 30%, it is difficult to obtain sufficient ferromagnetic properties and corrosion resistance at the same time, and if it exceeds 70%, there is a problem that the machinability of the composite particles is poor.

In addition, through the present invention, it is possible to provide a wire saw that is formed by attaching the composite particles having various ferromagnetic properties and corrosion resistance described above to the wire through an electrodeposition process.

A composite particle comprising a superhard particle according to a preferred embodiment of the present invention and a coating formed on the surface of the superhard particle will be described with reference to the drawings.

1 is a diagram illustrating a superhard particle according to the present invention and a film formed on the surface of the superhard particle. The ultra-hard particles 10 include particles selected from the group consisting of diamond, cubic boron nitride, silicon carbide, boron carbide, alumina, silicon nitride, tungsten carbide, zirconia or combinations thereof. In FIG. 1, in forming a metal film having a multi-layered electrical conductivity on the surface of the ultra-hard particles 10, the first layer 11 is formed on the top surface of the ultra-hard particles 10, and has a ferromagnetic metal It is made of, and by showing the second layer 12 made of a metal having excellent corrosion resistance again on the first layer, it shows composite particles that can withstand various electrolytes. FIG. 2 shows composite particles with a boundary layer 13 for increasing adhesion between the first layer exhibiting ferromagnetic properties and the ultrahard particles. The boundary layer is a metal layer simultaneously containing nickel and phosphorus having high adhesion, and the content of phosphorus is preferably 6 to 13% by weight.

Hereinafter, the present invention will be described in more detail through examples. The following examples illustrate the invention, and the invention is not limited thereto.

(Example 1)

Diamond particles were prepared as ultrahard particles. The particle size of the prepared diamond particles was 4 to 10 μm based on D ₅₀ . 10 g of the prepared diamond particles were kept stirred at 60 ° C. for 30 minutes in ion-exchanged water in which a degreasing agent (ACE CLEAN A-110, Okuno Corporation) was dissolved to remove foreign substances on the surface. After washing, the sensitization treatment was performed in a 60 ° C aqueous solution containing 1% by weight of stannous chloride (SnCl ₂ ), followed by stirring for 30 minutes in a 60 ° C aqueous solution containing 0.1% by weight of palladium chloride (PdCl ₂ ) for activation. .

Hydrazine hydrate (N ₂₎ was added to the aqueous solution of nickel sulfate prepared by dissolving 12 g of nickel sulfate (NiSO4 · 6H ₂ O) and 18 g of roxel salt (C ₄ H ₄ KNaO ₆ · 4H ₂ O) in distilled water while stirring. H ₄ · H ₂ O) 20 g and sodium hydroxide (NaOH) 10 g mixed distilled water was slowly added to form a first layer having ferromagnetism, filtered and washed with distilled water to produce diamond particles coated with the first layer. Did. Subsequently, 50 g of nickel sulfate (NiSO4 · 6H ₂ O) and 63 g of Roxel salt (C ₄ H ₄ KNaO ₆ · 4H ₂ O) were dissolved in distilled water, followed by stirring by adding diamond particles coated with the first layer to a nickel sulfate aqueous solution. Sodium hypophosphite (NaH ₂ PO ₂ ) 800 g and 80 g of ammonia (NH ₄ OH, 25%) dissolved in distilled water are slowly added to form a second layer composed of a metal containing nickel and phosphorus, followed by filtering. The final composite particles were prepared by washing with distilled water.

(Example 2)

Composite particles were prepared in the same manner as in Example 1, but when the first layer was formed, nickel sulfate was reduced to 8 g, and other reagents were proportionally reduced to reduce the weight of the first layer in the final composite particles.

(Example 3)

Composite particles were prepared in the same manner as in Example 1, but when the second layer was formed, nickel sulfate was reduced to 20 g and other reagents were proportionally reduced to reduce the weight of the second layer in the final composite particles.

(Example 4)

Composite particles were prepared in the same manner as in Example 1, while reducing the nickel sulfate to 8 g when forming the first layer and other reagents proportionally reducing it, and reducing the nickel sulfate to 20 g when forming the second layer, and other reagents. In proportion to this, the weight of the coating occupied by the final composite particles was reduced.

(Example 5)

Composite particles were prepared in the same manner as in Example 1, but the hyposensitized and activated diamond particles were added to the aqueous solution of nickel sulfate prepared by dissolving 4 g of nickel sulfate and 6 g of Roxel salt in distilled water before forming the first layer, and hypochlorous acid was stirred. A reducing layer made by dissolving 80 g of sodium and 8 g of ammonia water (25%) in distilled water was slowly added to form a boundary layer. Thereafter, formation of the first layer and the second layer was performed in the same manner as in Example 1.

(Example 6)

In the same manner as in Example 5, a boundary layer, a first layer, and a second layer were sequentially formed on the diamond particle surface, but nickel sulfate used for each layer was 4 g in the boundary layer, 12 g in the first layer, and 20 g in the second layer. Other reagents were used proportionally.

(Example 7)

In the same manner as in Example 5, a boundary layer, a first layer, and a second layer were sequentially formed on the surface of the diamond particles, but 200 g of sodium hypophosphite, 20 g of ammonia (25%), and 20 g of sodium hydroxide were distilled as a reducing solution in the first layer formation step. By dissolving in, the reaction pH was increased to form a nickel metal layer having a low phosphorus content in the first layer.

(Example 8)

In the same manner as in Example 6, a boundary layer, a first layer, and a second layer were sequentially formed on the diamond particle surface, but 30 g of dimethylamine borane (DMAB) and 5 g of citric acid were dissolved in distilled water as a reducing solution in the second layer formation step. Used.

(Comparative Example 1)

In the same manner as in Example 1, the sensitization treatment and activation treatment of the diamond particles were performed, and then 66 g of nickel sulfate and 100 g of Roxel salt were dissolved in distilled water, and the treated diamond particles were added to the aqueous solution of nickel sulfate, while stirring, 1,200 g of sodium hypophosphite. A reducing solution made by dissolving 50 g of ammonia water (25%) in distilled water was slowly added to form a surface layer composed of a single layer and containing nickel and phosphorus.

(Comparative Example 2)

In the same manner as in Example 1, sensitization and activation treatment of the diamond particles was performed, and then, after stirring the nickel particles, the treated diamond particles were added to the aqueous solution of nickel sulfate prepared by dissolving 37 g of nickel sulfate and 60 g of Roxel salt in distilled water. A reducing solution made by dissolving 35 g of ammonia water (25%) in distilled water was gradually added to form a surface layer composed of a single layer and containing nickel and phosphorus.

(Comparative Example 3)

In the same manner as in Example 1, the sensitization treatment and activation treatment of the diamond particles were performed, and then 68 g of nickel sulfate and 100 g of Roxel salt were dissolved in distilled water, and the treated diamond particles were added to the aqueous solution of nickel sulfate, followed by hydrazine hydrate 120 g and hydroxide. Distilled water mixed with 50 g of sodium was slowly added to form a surface film having ferromagnetic properties.

The ferromagnetic property evaluation and the corrosion resistance evaluation were performed for the diamond particles on which the surface coating made as described above was formed, respectively.

The ferromagnetic properties were evaluated by measuring the saturation magnetization value. In order to evaluate the saturation magnetization value of the powder, diamond particles with a film are pressed and pelletized, and the sample thus made is drawn using a vibrating-sample magnetometer (VSM) at room temperature to draw a magnetic hysteresis curve. The saturation magnetization value was determined.

Corrosion resistance evaluation is performed after leaving for 10 hours in an electrolyte solution containing sulfuric acid at pH 2.0, and observing the surface of the particles through a scanning electron microscope (SEM), depending on whether the coating layer has fallen off or other reaction compounds have not occurred. It was judged as good or bad.

Table 1 below summarizes the evaluation results for each Example and Comparative Example. As can be seen from the results, in Examples 1 to 8, both exhibited excellent ferromagnetic properties and at the same time, excellent corrosion resistance. FIG. 3 shows the results of SEM analysis after the corrosion resistance test of the composite particles on which the metal film was formed according to Example 3 was completed, and shows that there is no change in the film even when the electrolyte solution of a strong acid is maintained for a long time.

On the other hand, as in Comparative Examples 1 to 3, when only a single coating for corrosion resistance or a single coating for magnetism was formed on the surface of the ultrahard particles, the ferromagnetic properties were insignificant or the corrosion resistance was poor, so it could be applied in the electrodeposition process of various electrolytes. It was not possible to obtain a powder. 4 is a result of observing the composite particles according to Comparative Example 3 through corrosion resistance test through SEM. It can be seen that the surface was severely detached and plate-shaped nickel hydrate was formed.

Boundary layer 1st layer 2nd layer Saturation magnetization
(emu / g) Corrosion resistance Film layer
weight% P content
(weight%) Film layer
weight% P content
(weight%) Film layer
weight%  P (B) content (% by weight) Example 1 - - 11 0 47 10.5 (P) 6 Good Example 2 - - 7.7 0 48.3 11 (P) 4 Good Example 3 - - 15.5 0 25.8 11 (P) 10.5 Good Example 4 - - 11 0 27.2 11 (P) 6.5 Good Example 5 3.6 8 10.8 0 45 11 (P) 5 Good Example 6 4.9 11 14.7 0 24.6 11 (P) 9.5 Good Example 7 3.6 11 10 1.1 45 11 (P) 6 Good Example 8 4.9 11 14.7 0 24.6 0.5 (B) 9 Good Comparative Example 1 - - - - 59.2 13 (P) 1 or less Good Comparative Example 2 - - - - 45 13 (P) 1 or less Good Comparative Example 3 - - 59 0 - - 28 Bad

Although the present invention has been described herein with reference to some embodiments, it should be understood that various modifications and changes can be made without departing from the spirit and scope of the present invention, which can be understood by those skilled in the art to which the present invention pertains. something to do. In addition, such modifications and variations should be considered within the scope of the claims appended hereto.

Claims (13)

A composite particle comprising ultra-hard particles and a coating formed on the surface of the super-hard particles,
The coating,
A first layer formed on the surface of the ultra-hard particles and made of a ferromagnetic metal; And
A composite particle comprising a second layer formed on the first layer and made of a metal having better corrosion resistance than the first layer. According to claim 1,
The ultra-hard particles include particles selected from the group consisting of diamond, cubic boron nitride, silicon carbide, boron carbide, alumina, silicon nitride, tungsten carbide, zirconia, or combinations thereof. According to claim 1,
A composite particle comprising a boundary layer made of a metal having better adhesion to the ultrahard particles than the first layer, between the superhard particle surface and the first layer. According to claim 1,
The first layer comprises nickel and phosphorus, but phosphorus is composed of a metal of 5% by weight or less, composite particles. According to claim 1,
The second layer is composed of a metal containing nickel and phosphorus, but phosphorus is 6 to 13% by weight, composite particles. According to claim 1,
The second layer is composed of a metal containing nickel and boron, composite particles. According to claim 1,
The saturation magnetization value of the composite particles is 3 emu / g or more, composite particles. The method of claim 3,
The boundary layer is composed of a metal containing nickel and phosphorus, but phosphorus is 6 to 13% by weight, composite particles. According to claim 1,
The weight of the first layer is 5 to 20% of the total weight of the composite particles, composite particles. According to claim 1,
The weight of the second layer is 20 to 50% of the total weight of the composite particles, composite particles. The method of claim 3,
The weight of the boundary layer is 3 to 10% of the total weight of the composite particles, composite particles. According to claim 1,
The weight of the coating is 30 to 70% of the total weight of the composite particles, composite particles. A wire saw in which the composite particles according to any one of claims 1 to 12 are attached to a wire through an electrodeposition process.

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