JPH08206960A - Polishing tool and its manufacture - Google Patents

Abstract

PURPOSE: To improve working efficiency of polishing and accuracy of a worked surface, and to prevent a scratch from being generated on the worked surface of a workpiece by chips by forming a diamond coating film having a large number of fine recesses-projections in a part or over the whole surface of a surface of a polishing tool base material. CONSTITUTION: In a polishing tool base material, a surface is roughened so that a large number of fine recesses-projections are formed in uniform surface roughness, and it is covered with a prescribed metallic thin film according to its necessity, and next, a low suit film is formed on this surface according to its necessity, and is formed as a diamond coating film, and a desired polishing tool is obtained. Polishing is performed by a projecting part of the diamond coating film of its surface, and since chips generated at polishing work time are removed by a recessed part, working efficiency of polishing and accuracy of a worked surface can be improved, and polishing effect nearly equal to that in polishing using an abrasive grain can be attained, and generation of a scratch on the worked surface of a work piece can be restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel polishing tool and its manufacturing method.

[0002]

2. Description of the Related Art Polishing is a remarkably important technology in the field of parts processing such as precision and electronic-related equipment. In general, loose abrasive grain processing has been widely adopted, but in recent years it has been easy to work and has high processing efficiency. Therefore, the progress of fixed abrasive processing is rapid. The main tool for fixed abrasive grain processing is a grindstone using fine abrasive grains. However, the whetstone has a problem in that the truing property of the surface of the whetstone and the aging of the whetstone surface due to the removal of abrasive grains due to the passage of machining time and the amount of machining increase, etc. Can be performed relatively easily, but it becomes difficult for a surface having a complicated shape such as a spherical surface or an aspherical surface.

Further, a polishing tool in which a hard carbon film is formed on a flat base material is also known, and this film-forming polishing tool can be polished with the same accuracy as that of the surface polishing using a grindstone, and is resistant to wear. Since it is also excellent in workability, there is an advantage that there are no inconveniences such as the removal of abrasive grains like a grindstone and the need to correct the tool surface as the number of machining increases. However, this film-forming polishing tool has a problem that scratches are likely to occur on the work surface due to the cutting chips because there is no portion for releasing the cutting chips generated by the polishing process.

[0004]

Under these circumstances, the object of the present invention is to improve the processing efficiency of polishing and the accuracy of the processed surface, and to suppress the occurrence of scratches on the processed surface of the work due to the cutting chips. It is to provide a new polishing tool and a method for easily and efficiently manufacturing the same.

[0005]

As a result of intensive studies to develop a polishing tool having the above-mentioned favorable characteristics, the present inventor has found that a part or the whole surface of the base material of the polishing tool may be predetermined. The surface shape through the metal thin film is covered with diamond so as to have a large number of fine irregularities, by configuring the convex portion on the irregular surface as a polishing portion, the concave portion as the escape portion of the cutting chips generated by the polishing process, The inventors have found that the object can be achieved, and have completed the present invention based on this finding.

That is, the present invention includes a polishing tool base material and a thin film of at least one metal selected from platinum group metals and rhenium, which is provided partially or entirely on the surface of the base material. , A polishing tool comprising a diamond coating having a large number of fine irregularities, and this one,
The polishing tool base material is roughened so that a large number of fine irregularities are formed with a uniform surface roughness, and a thin film of at least one metal selected from platinum group metals and rhenium (hereinafter, The present invention provides a method for producing the same by coating a predetermined metal thin film) and then forming a diamond coating on the surface.

The material of the polishing tool base material used in the present invention is not particularly limited as long as it is a material normally used for the polishing tool or the base material thereof, and examples thereof include silicon, Aluminum, zirconia, silicon nitride, silicon carbide, alumina, iron, iron alloys, tool steel, cemented carbide and the like can be mentioned. Examples of the tool steel include SK, SKD, SKS, SKH, and the like, and examples of the cemented carbide include SF, G, D, and the like.

In other words, the polishing tool of the present invention is one in which a large number of diamond coatings having fine irregularities are formed partially or entirely on the surface of the base material of the polishing tool with a specific metal thin film interposed as the case may be. is there. The diamond coating provided on the surface of the base material for the polishing tool is not particularly limited as long as it is a coating of diamond composition formed as a surface coating on various molded products, wear resistant tools and the like. Examples of the molded product and the wear resistant tool include a lap segment, a precision grindstone, a polishing tool, and a lapping tool. Also, unlike the grindstone that causes desorption of abrasive grains, this coating is formed on the base material of the polishing tool with a certain size, so it has a strong adhesion, is super hard, and has a diamond composition that does not easily wear. Combined with this, it brings stability and durability of polishing performance. Further, the diamond coating may be formed via a predetermined metal thin film. Examples of the metal forming the predetermined metal thin film include a platinum group metal and rhenium. The platinum group metal is not particularly limited, and any of Pt, Ru, Ir, Rh, Pd and Os is used, but Pt is preferably used. , Ru or Rh are used.

It is important that the diamond coating has a large number of fine irregularities. These irregularities cause a surface roughness similar to that of a grindstone with abrasive grains on the surface of the polishing tool on which the diamond coating is formed.The convex portions are the polishing portions, and the concave portions are the escape portions of the cutting chips generated by the polishing process. Function as.

Next, in the polishing tool of the present invention, the polishing tool base material is surface-roughened so that a large number of fine irregularities are formed in a uniform surface roughness, and if necessary, coated with a predetermined metal thin film, Then, a low suit film may be optionally formed on this surface, and a diamond film may be formed on the surface to produce the film.

This manufacturing method will be described in more detail. For surface roughening, for example, silicon carbide or diamond particles having various particle sizes are attached to a support such as a plastic film or paper, and a polishing sheet having various roughnesses is used. Although it may be carried out according to the method used, it is preferably carried out by vibrating in a polishing liquid containing a polishing powder to scratch the surface. The polishing powder is not particularly limited as long as it is harder than the polishing tool base material, and suitable ones vary depending on the type of the polishing hard base material, etc., but in general, ultra-hard ones such as diamond powder The medium for forming the polishing liquid together with the polishing powder is not particularly limited as long as it does not adversely affect the polishing tool base material and the polishing powder, and examples thereof include water, alcohol and acetone. Ultrasonic treatment is preferably used as the vibration treatment in the polishing liquid.

Then, in the method of the present invention, the surface thus roughened is optionally coated with a predetermined metal thin film, and a low suit film is optionally formed on this surface to form a diamond coating. That is, the diamond coating may be directly formed on the roughened surface, or a low suit film may be first formed on the roughened surface, and then the diamond coating may be formed on this film. The flattened surface may be first coated with a predetermined metal thin film, and then a diamond coating may be formed on this thin film, or the roughened surface may be first coated with a predetermined metal thin film, and then this thin film is formed. A low suit film may be formed on and then a diamond film may be formed on this film. When coating a predetermined metal thin film, a coating method such as a sputtering method, an ion sputtering method, a vapor deposition method, an ion plating method, a plating method, a chemical plating (electroless plating) method is usually used.

The method of forming the diamond coating is not particularly limited, and examples thereof include microwave plasma CVD method, hot filament CVD method, direct current plasma CVD method, high frequency plasma CVD method, high frequency thermal plasma CVD method, ECR plasma CVD method, electron beam. Irradiation CVD method, ArF laser CVD method, vacuum ultraviolet light combined use electron beam gun CV
The D method or the like is used, but the microwave plasma chemical vapor deposition method is preferably used.

In the microwave plasma chemical vapor deposition method,
When methane is used as the carbon source for film formation, it is used as a mixture with hydrogen. At this time, the mixing ratio of methane and hydrogen is preferably in the range of 1: 100 to 5: 100 by volume. This hydrogen carries out hydrogen abstraction reaction of methane in the gas phase, activates chemical species, bonds to dangling bonds on the diamond surface, stabilizes carbon's SP ³ bonds, and carbon-hydrogen bonds on the diamond surface. Cutting by hydrogen abstraction reaction, radicalization or ionization of growing points,
Rearrangement of SP ² bonds to SP ³ bonds on the diamond surface, selective etching removal of amorphous components such as graphite that precipitate with diamond are performed. Further, by adding oxygen or water to this hydrogen, or by using methane and an oxygen-containing compound in combination, it is possible to more effectively remove the amorphous component by etching.

When the low suit film is formed in advance before forming the diamond film, the low suit film is preferably formed by suspending the low suit film in an alkaline solution and subjecting it to an electrolysis method or an electrophoretic deposition method. It is performed by forming a film on the polishing tool base material subjected to the surface roughening treatment. The alkaline solution is preferably a solution containing an alkali hydroxide, especially an alkali metal hydroxide such as sodium hydroxide, and an amine, especially a lower alkylene polyamine such as ethylene diamine. As a low suit, a carbon cluster low suit, for example, 15% by weight
C _{60 and the} like are preferable. The diamond film formation performed after forming the low suit film in this manner is preferably performed by a microwave plasma chemical vapor deposition method.

A particularly preferred coating forming method is to use a predetermined polishing tool base material at 300 to 1200 ° C., preferably 300 to 700.
C., more preferably to a temperature in the range 300 to 500.degree. C., on which methane 1 to 10% by volume, preferably 2 to
Microwaves are applied to generate plasma while flowing hydrogen gas containing 8% by volume. The gas pressure at this time is selected in the range of 1 × 10 ² to 1 × 10 ⁴ Pa, preferably 5 × 10 ^{2 to} 5 × 10 ³ Pa, and the microwave output in the range of 100 to 1000 W, preferably 300 to 500 W. The inflow time of hydrogen gas containing methane is 1 to
It is selected in the range of 25 hours, preferably 3 to 10 hours.

[0017]

In the polishing tool of the present invention, the convex portions of the diamond coating on the surface of the polishing tool are used for polishing, and the concave portions eliminate chips generated during the polishing process. It is possible to improve the accuracy, achieve a polishing effect equivalent to or similar to the polishing using abrasive grains, and to suppress the occurrence of scratches on the work surface of the workpiece. Further, according to the method of the present invention, it is possible to easily and efficiently manufacture such an excellent polishing tool.

[0018]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

Example 1 A silicon wafer flat plate having a diameter of 5.08 mm and a thickness of 3 mm was used as a base material for a polishing tool, and 2 g of diamond powder having an average particle size of 10 μm was dispersed in 300 ml of water. Put in, container, 20kHz, 20W
Ultrasonic vibration treatment was performed under the conditions described above to scratch the surface of the silicon wafer, and then a diamond coating was applied to the surface of the base material of the polishing tool to be treated under the conditions of Table 1 by the microwave plasma chemical vapor deposition method. This coating has a hardness Hv5
000 to 10,000, and 113 by Raman spectroscopy
1500 cm called the diamond peak at 3 cm ^-1
A broad spectrum of i-carbon is shown near ^-1 . In this way, a fixed grindstone made of a diamond-coated silicon wafer having a surface roughness of 0.08 μmRa was produced.

[0020]

[Table 1]

This fixed grindstone is rotated, and a silicon wafer is used as a work, and while this is supplied with a sodium hydroxide solution (pH 8.5) as a polishing liquid,
It was pressed and polished under a load condition of 90 gf / cm ² . The polished surface shows the same roughness as the 0.08 μmRa whetstone,
The roughness of the fixed grindstone was accurately transferred to the work. This grindstone maintains the initial roughness even after polishing for 60 minutes and is excellent in processing efficiency. By adjusting the surface roughness of the fixed grindstone, a work rough surface corresponding to it was obtained.

Example 2 A fixed whetstone coated with diamond as in Example 1 was used in the same manner as in Example 1 except that aluminum (2011, 2017, 5056) was used in place of the silicon wafer as the work. It was produced and polished. The roughness of the polished surface was 0.08 μmRa.

Example 3 A diamond coating similar to that of Example 1 was carried out in the same manner as in Example 1 except that ceramics ZrO ₂ , Si ₃ N ₄ or SiC sintered body was used as the work piece instead of the silicon wafer. The fixed whetstone that was applied was produced and subjected to polishing.
The roughness of the polished surface was 0.08 μmRa.

Example 4 As a work, instead of a silicon wafer, 13 × 13
Example 1 except that platinum having a thickness of 1 μm was chemically plated on the surface of a commercially available cemented carbide (TH10) of × 5 mm was used.
In the same manner as in Example 1, a fixed whetstone coated with the same diamond as in Example 1 was produced and polished. The roughness of the polished surface was 0.08 μmRa.

Claims (6)

[Claims] 1. A polishing tool comprising a polishing tool base material and a diamond coating having a large number of fine irregularities provided partially or entirely on the surface thereof. 2. A polishing tool characterized by roughening a polishing tool base material so as to form a large number of fine irregularities with a uniform surface roughness, and then forming a diamond coating on this surface. Method. 3. A polishing tool base material and a large number of fine irregularities formed on a surface thereof partially or entirely through a thin film of at least one metal selected from platinum group metals and rhenium. Polishing tool consisting of diamond coating. 4. A polishing tool base material is roughened so that a large number of fine irregularities are formed with a uniform surface roughness, and then at least one selected from a platinum group metal and rhenium is formed on this surface. A method of manufacturing a polishing tool, comprising coating a thin film of a metal of a seed and then forming a diamond coating on the surface of the thin film. 5. The method according to claim 2, wherein the surface-roughening is performed by subjecting the polishing tool base material to vibration treatment in a polishing liquid containing polishing powder to scratch the surface. 6. The method according to claim 2, 4 or 5, wherein the diamond coating is formed by microwave plasma chemical vapor deposition.