KR101155586B1 - Diamond tool and method of producing the same - Google Patents

Abstract

The present invention relates to a diamond tool and a method for manufacturing the same, and the diamond film and the coating material to form a variety of grooves and valleys on the surface of the material by a laser processing on the surface of the various materials on which the diamond film is coated and then coated The present invention relates to a diamond coating tool made of a method for greatly improving the adhesion strength of the liver and to a manufacturing method thereof, and particularly to a diamond coated material applicable to various fields requiring grinding and polishing properties and wear resistance of a diamond coating film. To provide a tool.

The laser processing is performed on the material to be coated with the diamond in a controllable shape, size, spacing, depth, etc., so that excellent adhesion can be achieved. This enables grinding and polishing operations using a diamond coating film. The effect of preventing peeling or dropping of the coating film can be obtained, thereby obtaining excellent cutting and abrasion resistance properties.

Meteorological chemical synthesis, diamond coating, laser processing, adhesion, grinding performance

Description

DIAMOND TOOL AND METHOD OF PRODUCING THE SAME

DETAILED DESCRIPTION The present invention provides a variety of applications in which a diamond film-coated material is applied to a thickness of several micrometers to several mm, such as a cutting tool, a special tool requiring wear resistance, a semiconductor crimping tool (TAB tool) or a CMP pad requiring surface grinding performance. This is to solve the problem of dropping the diamond coating film and improve the mechanical properties at the same time.In the conditioner, the surface of the diamond coating material is patterned in various shapes to form grooves and bends, and then the diamond film is coated. The present invention relates to a diamond-coated tool and a method of manufacturing the same, which secures and simultaneously apply this shape to grinding and polishing operations.

Diamond has the highest hardness and chemical stability among the existing materials and is used as an important material in fields requiring various mechanical properties. Especially, diamond film coated by CVD (Chemical Vapor Deposition) has 100% pure diamond property unlike sintered diamond (PCD) made by mixing metal binder and diamond powder. Very good properties in tooling and wear resistance

In order to use the diamond film coated by the vapor phase chemical synthesis method having such excellent characteristics, it is necessary to secure excellent adhesion strength between the diamond film coated material and the diamond film. However, using a transition metal such as Fe, Co, Ni, etc. as a substrate material, diamond coating is difficult, and even if the coating is made, it is almost impossible to secure adhesive strength. This is because these transition metals are coated with graphite, not diamond, as a graphitization catalyst for diamond.

Another problem is that the diamond film itself has a very large residual stress and is also chemically stable, making it difficult to form adhesion with the deposited material through chemical reaction. In addition, due to the difference in coefficient of thermal expansion with the substrate material, even if the thickness of the diamond film is only a few μm or more, the diamond film is easily peeled off from the substrate material, thereby causing problems in utilizing the characteristics of the diamond film. Therefore, the materials coated with diamond by the vapor phase chemical synthesis method are limited to very few materials such as cemented carbide (WC-Co) and SiC and Si ₃ N ₄ .

Of course, even in this limited material, a problem occurs in the adhesion of the diamond coating, and therefore, various methods have been proposed to solve this problem. For example, in the case of cemented carbide material, as in US Pat. Nos. 5,585,176 and US 6,365,230, Co is completely removed through a chemical etching method, and then only the particles of the surface are grown by heat treatment at a high temperature to secure adhesion.

In the case of the ceramic material, unlike the cemented carbide material, there is no transition metal that acts as a catalyst for diamond, but due to the stability of the ceramic itself, it is more difficult to obtain excellent adhesion with the coated diamond film. Therefore, in the case of ceramic materials, efforts have been made to improve adhesion to diamond by changing the microstructure. As in US Pat. No. 5,334,453 and Korean Patent No. 290683, a large and long particle was formed on the surface of the ceramic material to improve mechanical interlocking with the coated diamond film, thereby obtaining adhesion. That is, ceramic materials such as SiC and Si ₃ N ₄ can make needle-shaped particles by changing the sintering temperature, and are a method of securing adhesion by exposing these particles to the surface to promote mechanical bonding with the diamond film.

However, all of these methods are limited to materials having a few needle-like microstructures, and necessitate complicated processes such as cumbersome heat treatment processes and difficult chemical etching. Of course, it is considered that there is a problem in securing sufficient adhesion even in such a controlled microstructure.

The present invention seeks to obtain excellent adhesion even in general materials by overcoming the limitation of the improvement of adhesion by changing the microstructure seen in a few materials, and mechanical impact even in a thick diamond film-coated material having a thickness of several μm to several mm. It is an object of the present invention to provide a diamond coating composite having sufficient adhesion to withstand, and at the same time to produce a tool that realizes excellent mechanical properties. In particular, the surface of the material on which the diamond is to be deposited is laser processed to achieve the desired depth, length and shape, thereby obtaining excellent adhesion. In addition, a tool for applying a coated diamond film by such a shape to grinding or polishing the workpiece It is for the purpose of use.

The most effective method for obtaining good adhesion in the diamond film coated by the vapor chemical synthesis method is to form a structure in which the coated films on the surface of the material substrate to be coated cannot be mechanically intertwined with each other. In other words, to create a structure that maximizes the mechanical interlocking effect (mechanical interlocking). As mentioned above, the methods provided in the literature for improving the adhesion of the diamond coating film were all methods of maximizing such mechanical entanglement effects.

In order to maximize the mechanical entanglement effect, various machining patterns can be made on the surface of the material by using mechanical processing methods such as diamond grinding wheels or drills. Patterning consisting of grooves and irregularities in desired shape freely in size is almost impossible and economically unappropriate approach.

It is an object of the present invention to provide a method and shape processing for obtaining such mechanical interlocking through a laser.

In addition, in order to use a diamond-coated tool as a grinding tool or an abrasive tool, it is intended to apply the shape to the tool by laser processing the surface of the material to be coated with diamond.

The unique feature of laser processing is that unlike conventional methods, it is possible to create a processing shape on a surface with a desired depth, length, and shape on various materials regardless of microstructures or components. The advantage is that you can optimize the performance.

Conventional laser processing has been applied to cutting and marking of products. However, the present invention intends to apply to the method of surface micromachining to secure adhesion between dissimilar materials through the conversion of the concept in the limited use of the laser and to the shape fabrication for improving the performance of the grinding tool.

The lasers applied to the surface processing are most laser methods such as fiber laser, CO ₂ laser, Nd-YAG laser, excimer laser, pico laser and femtosecond laser. Although this is applicable, in order to process the desired small size and depth (for example, several micrometers to several hundred micrometers) in the material to be coated with diamond, a fiber laser mainly used for marking products is preferable in consideration of economical aspects. . Looking at the surface processing method using this laser, the first step is to form (pattern) grooves and valleys using a laser on a selected shape on a selected material, and in the second step to remove impurities around the grooves formed by laser processing. After the etching process, the third step is to coat a diamond film having a thickness of several micrometers to several mm through vapor chemical synthesis to obtain a diamond film-coated composite or a grinding and polishing tool.

Of course, the diamond-coated material through this method is applied as a material requiring abrasion resistance by mirror polishing the surface, and on the other hand, CMP by applying the surface shape of the rough bend formed by the laser processed pattern as it is. Applied to grinding or grinding tools such as pad conditioners.

At this time, the coating of diamond is possible in all known ways, for example, hot filament CVD, microwave PECVD (Plasma Enhanced Chemical Vapor Deposition), DC-PECVD (Direct Current-Plasma Enhanced Chemical Vapor Deposition) is possible. The source gas for the diamond coating may be hydrogen, argon and the like added based on methane, and a third elemental gas such as nitrogen and oxygen may be added for particle control.

Diamond tool manufacturing method according to the invention comprises the steps of preparing a substrate; Laser processing the surface of the substrate to form grooves; And depositing a diamond film on the surface of the substrate on which the groove is formed, wherein a thick diamond deposition film having excellent adhesion is possible.

Furthermore, after the step of forming a groove in the substrate by laser processing, it is preferable to further include the step of removing impurities around the groove by etching the substrate with a NaOH solution.

In addition, the step of depositing the diamond film, may be made of any one of hot filament CVD, microwave PECVD, DC-PECVD, the step of depositing the diamond film, it is preferable to use methane, hydrogen or argon as the source gas.

Further, the step of depositing the diamond film, characterized in that the temperature of the substrate at a filament temperature of 2100 ^° C and a substrate temperature of 900 ^° C as a raw material of hydrogen gas containing 3 vol% methane is made under a pressure of 60 torr.

The step of laser processing the surface of the substrate may use a single mode fiber laser in the exposure conditions of 6 to 20 W, 20 Hz, 2 ms, the laser is a fiber laser (COber laser), CO ₂ laser, Endiyag (Nd-YAG) laser, excimer (excimer) laser, pico (pico) laser, femto (femto) is characterized in that any one of the laser.

Further, the diamond film is preferably deposited to a thickness of 3㎛ 500㎛, more preferably 30㎛ 100㎛, the substrate is SiC, Si ₃ N ₄ Or WC-Co (carbide material).

In addition, the preparing of the substrate may include: obtaining a sintered body by applying atmospheric pressure sintering; Adding 1% B ₄ C by volume to the SiC powder as a sintering aid and then mixing in a ball milling method; Drying the mixed powder; And after molding the dried powder, it is characterized in that it comprises a step of sintering at 2100 ^o C for 2 hours while maintaining at 1 atm argon in the sintering furnace of the graphite heating element.

In the application of the diamond film coated by the gas phase chemical synthesis method according to the present invention, it is possible to apply a wide range of diamond film in the application field of the thick diamond film, which has been limited to use due to the problem of adhesion, and above all, the long particle shape in the angular shape Diamond coating membranes, which were only applicable to materials with microstructures, solve these limited constraints and enable wider applications.

In particular, it is possible to apply a thick diamond deposition film having excellent adhesion to the grinding and cutting process using the angular shape of the diamond particles themselves, and at the same time can be applied even in harsh environmental conditions. In addition, diamond films can be used in common materials without complicated heat treatment processes or difficult etching processes, thereby expanding the application of diamond coating films to new fields that were previously difficult to apply.

In addition, unlike conventional, the surface of the material on which the diamond film is to be coated is freely processed by a laser and the shape of the diamond is applied to the grinding and polishing tool as it is. It is an opportunity to expand the application area of the system.

Hereinafter, an embodiment of a diamond tool and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

It is an object of the present invention to obtain a diamond composite coated diamond composite material and a tool exhibiting excellent adhesion. Using laser processing, grooves or bends are formed on the surface of the material, thereby maximizing the mechanical bonding force of the diamond film, and freely realizing the roughness, shape, and depth of the surface by controlling the output of the laser.

In addition, the diamond is deposited on the surface of the laser processed material as it is to be applied as a grinding and polishing tool.

Hereinafter, the specific method for the surface processing of the material and the coating of the diamond film will be described through an embodiment.

Example  One

SiC substrates were fabricated for diamond coating. A normal SiC sintered body was obtained by applying atmospheric pressure sintering. About 1% of B ₄ C was added to the SiC powder in a volume ratio as a sintering aid and mixed for 24 hours by a ball milling method. The mixed powder is dried and molded using a metal mold having a diameter of 20 mm, and then sintered at 2100 ^o C for 2 hours while argon (Ar), which is an inert gas, is kept at 1 atm in a sintering furnace of a graphite heating element. The sintered compact of was obtained. The SiC substrate thus obtained was ground using a diamond grinding wheel for surface planarization.

A uniform groove was formed on the surface of the planar SiC substrate obtained by using a 20 W class single mode fiber laser at intervals of 0.2 mm at an exposure condition of 6 W, 20 Hz, and 2 ms. Figure 1a is a microstructure photograph of the grooves observed after the removal of impurities by etching with a NaOH solution to the laser-processed SiC specimens. On the surface of the SiC material, it can be seen that grooves of a certain size are formed at intervals of 0.2 mm which are processing conditions under regular conditions. Figure 1b is an enlarged observation of one of these processing grooves, it can be seen that formed to a depth of about 20 ㎛ in a size of about 25 ㎛, the width decreases in the depth direction of the groove by the laser conditions and processed into a cone shape You can see that. Of course, it is possible to change the size and shape and depth of the grooves formed by changing the output of the laser, it is possible to implement the appropriate bonding force and processing shape according to the thickness of the diamond film to be coated.

In order to confirm the processing state of the laser and to check the adhesion by diamond coating, the surface was processed with a laser under the same conditions as in FIG. 1 in SiC. Laser-etched and etched SiC specimens were pretreated for 10 minutes in an ultrasonic vibrator in an ethanol solution containing diamond powder to increase the nucleation density of the diamond. After the pretreatment, the SiC specimens were washed and loaded into a hot filament CVD synthesis apparatus for diamond coating, followed by diamond coating. The diamond coating speed in the hot filament CVD apparatus is about 1 μm / h, but has a disadvantage of being able to synthesize a large amount of specimens at the same time. Diamond coating conditions were carried out under a pressure of 60 torr with hydrogen gas containing 3 vol% of methane as a raw material at a filament temperature of 2100 ^° C and a substrate temperature of 900 ^° C.

FIG. 2 is a cross-sectional microstructure obtained by depositing diamond and polishing a cross section for 100 hours on a laser processed SiC specimen. A diamond film 30 coated on the SiC material 10 with a thickness of about 100 μm is observed, and grooves 20 formed by a laser are identified at the interface between the diamond film 30 and the ceramic (SiC) material 10. These grooves 20 have a depth of about 20 ㎛, all can be seen that the diamond film 30 is filled and coated.

Since these deposited films were retained as they were, even though the load was directly applied to the thick diamond deposited film by a grinding process with a diamond grinding wheel, it can be seen that very good adhesion was achieved. On the other hand, when the diamond film was deposited for 100 hours on a SiC substrate without laser processing, the diamond deposition film was easily peeled off from the substrate due to the curb load of the diamond wheel, and thus showed very weak adhesion.

On the other hand, for quantitative adhesion evaluation, a diamond film was deposited to a thickness of about 30 μm on a laser-processed SiC substrate under the same conditions, and the adhesion was evaluated using a Rockwell hardness tester with a load of 60 kg. 3 shows that the microstructure, only the trace 40 of the tip of the cone indented by the Rockwell diamond cone around the indentation is observed, the peeling of the diamond deposition film is suppressed.

On the other hand, in the case of a specimen in which a thin diamond film of about 15 μm was deposited by depositing a diamond film for 15 hours on a non-laser SiC specimen, as shown in FIG. 4, around the indentation point 40 by a 60 kg load, as shown in FIG. 4. It was confirmed that all the diamond films of were easily peeled off. From this, it can be confirmed that the adhesive force effect is very large by surface laser processing of the ceramic material.

Example 2 .

Example 2 is an example which acts as a grinding and polishing tool using the shape of the board | substrate processed with the laser as it is. Example 2 is the same as the whole process of Example 1. That is, the prepared SiC substrate is processed with a laser and coated with diamond to a thickness of 30 μm after pretreatment.

5A shows the microstructure obtained in this way. It can be seen that a uniform diamond film of a certain height protrudes 50 in accordance with the size of the processing groove around the laser processing groove. FIG. 5B is an enlarged microstructure of one of these processing grooves, and a diamond film protrudes around the grooves at a height of about 3-5 μm in accordance with the size of the laser processing grooves as indicated by the dotted circle. This phenomenon is also a bright area around the processing groove in 1b due to a processing phenomenon in which the laser beam is momentarily protruded and dissolved around the groove hit by the laser beam. These microstructures can be applied very efficiently and usefully in the grinding and processing of planes. That is, it is a tool that is applied to the grinding and polishing process of other materials with the roughness according to the sharp crystal surface of diamond grains protruded along the groove, and shows excellent mechanical properties. Through the space of the grinding can be obtained the effect that the residue of the workpiece is easily discharged out.

As described above, the diamond film is deposited on the laser processed shape as it is, and thus, the grinding and polishing tools can be manufactured and applied. In particular, the shape of such a tool has the great advantage of being utilized as a CMP pad conditioner tool applied to the planarization process of semiconductor wafers.

6A and 6B are schematic representations of the process to explain the results of Example 2 in more detail. In FIG. 6A, grooves 60 are formed in the SiC substrate 10 due to laser processing, and at the same time, protrusion 70 regions are formed around the grooves 60 by-products by laser processing. Thereafter, as shown in FIG. 6B, a uniform diamond coating film 80 is formed on the SiC substrate 10 by diamond coating, but a uniform diamond coating film is formed on the protrusion 70 by laser processing. The resulting diamond film 90 of one size and uniform shape is formed. These protruding diamond regions 90 are subjected to grinding and polishing processes. In conclusion, the shape on the substrate formed by the laser groove 60 not only greatly improves the adhesion of the coated diamond film, but also the protruding shape 90 of the diamond coating film is very effective and unique as a tool for grinding and polishing processes. Will have

Example 3.

The SiC substrate obtained by sintering was processed at intervals of 0.1 mm using a 20 W class single mode fiber laser at 20 W, 20 Hz, and 2 ms exposure conditions. 7 is a microstructure of the surface of the SiC substrate material thus processed. Unlike in Figure 1 it can be seen that the size of the groove (dimple) is very deep and large. From this, it can be seen that the size and shape change is easy through the change of the laser output.

The processed specimen was etched in a NaOH solution for 10 minutes to remove impurities, and pretreated with an ultrasonic vibrator for 10 minutes in an ethanol solution containing diamond powder. After pretreatment it was washed and loaded into a hot filament CVD synthesizer for diamond coating, followed by diamond coating for 15 hours. Diamond coating conditions were carried out under a pressure of 60 torr with a hydrogen gas containing 3 vol% of methane as a raw material at a filament temperature of 2100 ^° C at a temperature of 900 ° C.

8 shows a microstructure coated with a diamond film, which is an enlarged observation of one of many uniform processing grooves. The diamond film is uniformly coated along the processing grooves formed by the laser. In addition to showing excellent adhesion, the grooves formed facilitate the discharge and removal of the grinding residue during the grinding and polishing process, and these microstructures greatly improve the grinding efficiency. In other words, by using the processing and coating phenomena, it is possible to apply laser beams to various shapes and apply these thick diamond coating films to the grinding and polishing process.

In the embodiment of the present invention described so far, the grooves processed by the laser are described as only a plurality of circular grooves independent of each other (as viewed in plan view), but the circular grooves are formed in a continuous pattern, that is, in a line shape with each other. It is also possible to form in a (valley) pattern.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims. Of the present invention.

1a and 1b is a microstructure photograph of the surface of the SiC material after laser processing;

Figure 2 is a photograph taken after the deposition of a diamond film on the material of Figures 1a and 1b 100㎛;

3 is a photograph taken after the indentation is applied to the material of FIG.

4 is a photograph taken after the indentation is applied to the SiC material on which the diamond film is deposited without laser processing;

Figures 5a and 5b is a photograph taken after the deposition of a diamond film on the material of Figure 1;

6A and 6B schematically illustrate grooves formed in the SiC material surface;

7 is a photograph taken after processing the surface of the SiC material with a laser; And,

FIG. 8 is a photograph taken after deposition of a diamond film on the material of FIG. 7.

<Explanation of symbols for the main parts of the drawings>

10: SiC material 20: groove

30: diamond film 60: groove

70: protrusion 80: diamond film

Claims (13)

Preparing a substrate comprising any one of SiC, Si ₃ N _4, or WC-Co; Forming a groove by processing the surface of the substrate with a single mode fiber laser at an exposure condition of 6 to 20 W, 20 Hz, and 2 ms; And Depositing a diamond film on a surface of the substrate on which the groove is formed to form a diamond film protruding from the groove; Diamond tool manufacturing method for polishing and grinding tools comprising a. The method according to claim 1, After forming a groove in the substrate by laser processing, And etching the substrate with NaOH solution to remove impurities around the grooves. The method according to claim 1, The step of depositing the diamond film is a diamond tool, characterized in that made of any one of hot filament CVD, microwave PECVD, DC-PECVD. Manufacturing method. The method of claim 3, The depositing of the diamond film, the diamond tool manufacturing method, characterized in that hydrogen or argon is further added to the raw gas methane. The method of claim 4, The step of depositing the diamond film, the diamond tool manufacturing method, characterized in that made of a hydrogen gas containing 3 vol% of methane as a raw material under a pressure of 60 torr at a filament temperature of 2100 ^o C at a substrate temperature of 900 ^o C. delete delete The method according to claim 1, The diamond film is a diamond tool manufacturing method, characterized in that deposited to a thickness of 3 ㎛ to 500 ㎛. The method of claim 8, The diamond film is a diamond tool manufacturing method, characterized in that deposited to a thickness of 30 ㎛ to 100 ㎛. delete The method according to claim 1, Preparing the substrate is: Obtaining an SiC sintered powder by applying an atmospheric pressure sintering method; Adding 1% B ₄ C by volume to the SiC sintered powder as a sintering aid and then mixing in a ball milling method; Drying the mixed powder; And After molding the dried powder, the diamond tool manufacturing method comprising the step of sintering at 2100 ^o C for 2 hours while maintaining at 1 atm of argon in the sintering furnace of the graphite heating element. A diamond tool made according to the method of any one of claims 1, 2, 3, 4, 5, 8, 9 and 11. delete

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