JP2003159653A - Abrasive material having amorphous surface layer and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abrasive material with which a device can be simplified, costs can be lowered and maintenance can be carried out easily, and also the problem of the uneven distribution of abrasive grains and the problem of which the desired degree of the flat cannot be obtained due to the deformation of a pad can be solved without the need of supplying a slurry stably. <P>SOLUTION: This is the abrasive material formed by a CVD method and having the amorphous layer of an inorganic compound of which the surface roughness Ra is in the range of 1-10 μm on the surface, and the abrasive material in which a porous ceramic layer is formed under this amorphous layer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abrasive used for grinding or cutting metal, glass, ceramics, semiconductors and the like (these are referred to as grinding) and a method for producing the same.

2. Description of the Related Art Conventionally, in order to obtain a highly smooth mirror surface, polishing using an apparatus 1 shown in FIG. 1 has been performed. In the figure, an apparatus 1 has a head 2 and a table (surface plate) 3 that rub against each other, and the head 2 has a role of holding a work material 4 and pressing it against the table 3 while rotating. On the other hand, while the table 3 rotates, the work 4 is received by a resin porous body or cloth called a pad (polishing cloth) 5. At this time, while the solution (slurry) 6 in which the abrasive particles are dispersed is supplied between the work material 4 and the table 3 to which the pad 5 is attached, the head 2 and the table 3 rotate independently of each other, so that the abrasive particles work. Grind evenly.

In this method, since the pad is damaged seriously, there is a problem that the work must be interrupted frequently because the pad is frequently replaced, resulting in poor work efficiency.
Moreover, since this pad is expensive, it greatly affects the cost. On the other hand, since the slurry is a dispersion liquid of ultrafine particles called abrasive grains, this liquid scatters and contaminates the surroundings, so that the work environment is deteriorated by dust. This not only affects the health of the worker, but also in the semiconductor manufacturing process or the like, this dust becomes an adhered matter called a particle and contaminates the product. Even if this work is performed in an isolated room, it requires a high cost and labor to maintain the equipment. Further, although the slurry is supplied from the vicinity of the head, it easily spreads to the outer circumference of the head but does not easily penetrate to the central part. Moreover, since the pad is made of a soft resin such as porous resin or fiber, the periphery of the head and the periphery of the work material are easily ground, and it is difficult to perform grinding with excellent flatness. Further, in this processing method, since the grinding speed is slow, there is a problem in that the number of steps is increased and becomes complicated because the final step can be proceeded only from a smoothed state to some extent. Furthermore, the abrasive grains in this slurry tend to settle, and a stirring mechanism for constantly uniformly dispersing them and a mechanism for supplying this slurry are also required, which causes a problem that the apparatus becomes complicated. In addition, as another problem, this slurry is expensive, there are cases where not only abrasive grains are dispersed but also chemicals such as caustic potassium are dissolved, and these cannot be drained to sewer as waste liquid as they are. Treatment equipment for removal is also required. Recently, in order to solve these problems, a method of grinding abrasive particles called a fixed abrasive method with a grindstone solidified with resin or binder has been attempted, but there are still problems such as scratches (fine scratches). is there.

[0003]

According to the present invention, it is not necessary to stably supply the slurry, the apparatus can be simplified, the cost can be reduced, the maintenance can be facilitated, and the uneven distribution of abrasive grains and An object of the present invention is to provide an abrasive capable of solving the problem that desired flatness cannot be obtained due to deformation of the pad. Another object of the present invention is to provide an efficient manufacturing method of the above abrasive.

According to the present invention, C is formed on the surface of a substrate.
It was made based on the finding that the above problem can be efficiently solved by using, as the abrasive, the one in which the amorphous layer of the inorganic compound having the surface roughness Ra in the range of 1 to 10 μm is formed by the VD method. . That is, the present invention provides an abrasive, which is formed by a CVD method and has an amorphous layer of an inorganic compound having a surface roughness Ra in the range of 1 to 10 μm on the surface. The present invention also provides a surface roughness R on the surface of the substrate by the CVD method.
Provided is a method for producing an abrasive, which comprises forming an amorphous layer of an inorganic compound having a in the range of 1 to 10 μm.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION As the substrate used in the present invention,
Examples include various metals such as iron, nickel, copper and aluminum, and plate-shaped materials such as alloys thereof, rectangular parallelepipeds, and cylinders. Preferably, a platen substrate,
It is preferable to use a material that has sufficient strength so that it does not bend due to the head pressure and that can sufficiently adhere to the amorphous layer. Appropriate pretreatment and base treatment can be performed to improve adhesion. Further, instead of the surface plate, it may be formed on a foil or a plate, and may be fixed by adhering or adhering to the surface plate. In the present invention, a surface roughness Ra of 1 to 10 μm is directly formed on this by a CVD method.
It is possible to form an amorphous layer of an inorganic compound within the range. The CVD method is a method of forming a metal or its reaction product as a film on a base material by using a vaporizable compound gas of a metal, and a typical method is a thermal CVD method or plasma CV.
Method D can be mentioned. Of these, plasma CVD
The method is the most excellent method capable of forming a film at a low temperature and having a high forming speed and capable of forming a thick film. The plasma CVD method includes direct current plasma method, RF plasma method, EC
R plasma method, UR plasma method according to Uramoto's invention (JP-A-1-252781 and JP-A-1-259163)
No. gazette) and the like.

U by ECR plasma method and Uramoto's invention
The R plasma method has a high film formation speed, and the UR plasma method is particularly suitable because the cathode for generating plasma is devised. In the UR plasma method, Japanese Patent Laid-Open No. 6-
There are a method of using a metal for an anode as described in Japanese Patent No. 280025, and a method as described in Japanese Patent Application Laid-Open No. 2-2056884 and Japanese Patent Application Laid-Open No. 4-110473, which is performed without melting the anode. By using an anode having a similar structure as described in JP-A-9-118983 and JP-A-11-269655, particularly stable film formation is possible, and a film suitable for use in the present invention can be stably formed. The method described in the above publication is included in the present specification. Here, as the amorphous layer, tungsten, silicon, oxides, nitrides and carbides of silicon, carbon, Al2O3,
It is preferably formed of a material selected from BN. Of these, silicon and SiO2 are preferred. The amorphous layer used in the present invention is preferably such that no peak showing crystallinity is observed by X-diffraction.

The thickness of the amorphous layer needs to be larger than the surface roughness, usually 5 μm or more, and preferably 5 μm or more.
-60 μm, more preferably 10-40 μm. or,
The surface roughness Ra is 1 to 10 μm, preferably 3 to 6 μm. The surface roughness Ra can be easily measured by the method described in JISB0601-1994. The surface roughness can be adjusted by a method of previously adjusting the base to an appropriate roughness or a method of adjusting the surface to an appropriate roughness after film formation. Examples of such an adjusting method include a mechanical grinding method and a melting method. As the mechanical grinding method, a milling machine or the like is used to form various shapes (such as grooves) by cutting, or a method of forming a grinding groove by grinding with a coarse grindstone or a method of forming irregularities by a blast method. Etc. Further, the dissolution method includes a chemical polishing method of immersing in a solution and polishing by a chemical action, and an electrolytic polishing method of energizing and electrolyzing. In order to adjust the surface roughness of the underlayer and the film, it is preferable to select either one of the most suitable methods.

Further, as a method for forming the roughness of the base, a method of forming a film (preferably a porous ceramic film) having an appropriate surface roughness on a substrate and forming an amorphous layer on the film is performed. it can. In this way, as a method for forming a film having an appropriate surface roughness on the substrate,
Examples thereof include a spraying method and an anode spark discharge method. In particular, the method by the anode spark discharge method as described in Japanese Patent Publication No. 58-17278 is preferable because a film having Ra1 or more can be easily formed in good contact with the substrate and can be formed into various shapes. The thickness of the layer thus provided is not limited, but is preferably about 5 to 50 μm. When a porous ceramic film is used as such a film, the amorphous layer collapses during grinding to generate fine abrasive grains, and a new void called a chip pocket is formed due to the collapse, and there is no clogging by grinding debris. It is preferable because grinding can be continuously performed and high-speed and ultra-precision processing can be performed. Examples of the material of this layer include silicon dioxide, aluminum oxide, titanium oxide, mullite and sialon. In the abrasive of the present invention, the type of work material is not particularly limited, but silicon, glass, quartz, carbon sintered body, etc. can be suitably ground.

[0008]

According to the present invention, it is not necessary to stably supply the slurry, the apparatus can be simplified, the cost can be reduced and the maintenance can be facilitated, and the uneven distribution of the abrasive grains and the pad It is possible to provide an abrasive that can solve the problem that desired flatness cannot be obtained due to deformation. Further, by using the abrasive of the present invention, it is possible to solve the problem that free abrasive grains scatter and have an adverse effect on the working environment, and further the problem that not only the object to be ground but also surrounding items are contaminated. Furthermore, it is possible to avoid an increase in cost due to abrasion of the polishing pad due to loose abrasive grains and an increase in the amount of work required for replacement. In addition to the above advantages, the use of the abrasive of the present invention enables highly precise grinding with high processing efficiency without using a slurry. Therefore, it can be suitably applied to grinding in a manufacturing process of a silicon wafer, polishing (commonly called CMP) in a process of manufacturing a device using a silicon wafer, precision processing of a lens, an optical reflection plate, and ceramics. Next, the present invention will be described by showing Examples and Comparative Examples.

[0009]

Example 1 A surface plate that can be mounted on a flat aluminum grinding machine was prepared. A porous ceramic layer of SiO ₂ having a thickness of 35 μm was formed on one surface of this board (made of aluminum alloy (A5052)) by the anode spark discharge method in the same manner as in Example 3 of JP-B-58-17278. On top of this, the UR plasma gun according to the invention of Uramoto was used as the cathode, and
Plasma C using the anode described in FIG. 1 of 9655.
An amorphous Si film having a thickness of 30 μm was formed by the VD method. Thus, a composite film consisting of two layers of 65 μm SiO ₂ ceramics and an amorphous Si film was formed on an aluminum surface plate. The surface roughness was Ra 5.8 μm. The platen thus formed with a film is set on a polishing device (trade name "Abramin" manufactured by Struers) as shown in FIG.
25 mm x under the following conditions using ion-exchanged water as a lubricant
A test piece (silicon wafer) cut into 25 mm was ground. In addition, this test piece was already ground smoothly.

The surface roughness of the work material is Ra 0.0 before grinding.
It was 03 μm, which was almost unchanged from Ra 0.004 μm even after 9 hours of grinding, and was always about 0.9 mg / h · cm.
A grinding amount of ² was obtained and constant smooth grinding was possible. The surface roughness of the surface plate after grinding was Ra 4.8 μm, and the initial surface roughness was maintained. Furthermore, the amount of coating loss in this experiment was at most 5 μm, and the Si of the underlayer was observed by microscopic observation.
It was confirmed that the O2 ceramics layer was not exposed. Therefore, it was confirmed that the upper Si layer exerted the grinding action.

Example 2 On an aluminum surface plate similar to that of Example 1, SiO ₂ ceramics of the same type and thickness were formed as an underlayer, and an amorphous SiO ₂ film 10 μm was formed on the upper layer by the same CVD method. The surface roughness Ra was 4.5 μm. Similar to Example 1, the same silicon wafer was ground using ion-exchanged water as a lubricant. The surface roughness of the work material was Ra 0.004 μm before grinding, and Ra 0.
Although it was slightly increased to 007 μm, there was almost no change, and the grinding amount was always about 0.7 mg / h · cm ² , and constant smooth grinding was possible. The surface roughness of the surface plate after grinding was Ra 4.4 μm, and the initial surface roughness was maintained.

Comparative Example 1 By the same method as in Example 1, CVD was performed directly on an aluminum surface plate.
A Si film of 30 μm was formed by the method. Surface roughness is Ra
It was 0.3 μm. Similar to Example 1, the same silicon wafer was ground using ion-exchanged water as a lubricant. The surface roughness of the work material was Ra 0.007 μm before grinding and was 15
Even after grinding for a minute, Ra was 0.007 μm, which was almost unchanged, but the grinding amount was about 0.09 mg / h · cm ² ,
It was found that about 1/10 of Example 1 was hardly ground.

[Brief description of drawings]

FIG. 1 shows a schematic view of an apparatus commonly used for grinding to obtain a highly smooth mirror surface. In the figure, 2 is a head, 3 is a table (surface plate), 4 is a work material, and 5 is a pad (polishing cloth).

Claims (7)

[Claims] 1. An abrasive material, which is formed by a CVD method and has an amorphous layer of an inorganic compound having a surface roughness Ra in the range of 1 to 10 μm on the surface. 2. The abrasive according to claim 1, wherein a porous ceramic layer is formed on a substrate, and an amorphous layer of an inorganic compound having a surface roughness Ra in the range of 1 to 10 μm is provided on the porous ceramic layer. . 3. The abrasive according to claim 2, wherein the porous ceramic layer is formed by an anode spark discharge method. 4. The abrasive according to claim 1, wherein the amorphous layer is a layer whose peak is not detected by X-ray diffraction. 5. The grinding according to claim 1, wherein the amorphous layer is formed of a material selected from tungsten, silicon, silicon oxides, nitrides and carbides, carbon, Al 2 O 3 and BN. Material. 6. A method of manufacturing an abrasive material, which comprises forming an amorphous layer of an inorganic compound having a surface roughness Ra in the range of 1 to 10 μm on the surface of a substrate by a CVD method. 7. A porous ceramic layer is formed on the surface of a substrate by an anode spark discharge method, and then an amorphous layer of an inorganic compound having a surface roughness Ra of 1 to 10 μm is formed thereon by a CVD method. And a method for manufacturing an abrasive.