JPH11138447A - Polishing molding, polishing surface plate and polishing method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable excellent polishing by molding and working a polishing molding of silica powder, chamfering its boundary portion between a polishing surface and a widthwise surface, assembling the molding into a polishing surface plate, and thereby using polishing fluid containing no floating abrasive grains. SOLUTION: A polishing molding 3 suitable for polishing substrate material of an oxide substrate such as silicon wafer or lithium niobate contains mainly 90 wt.% or more of silica component. In such a molding, a boundary between a polishing surface in contact with the material to be polished of the polishing molding 3 and a widthwise surface is chamfered. An angle 4 formed by a tangential line in the entering direction of the polished material at a contact point, and a tangential line 2 in the widthwise direction of the polishing molding at the contact point shows a counterclockwise value with the tangential line 1 being a reference. The polishing molding 3 preferably shows bulk density ranging between 0.2 and 1.5 g/cm<3> , a BET specific surface area ranging between 10 and 400 m<2> /g, a mean grain size ranging between 0.001 and 0.5 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded body for polishing suitable for polishing silicon wafers, oxide substrates such as lithium niobate and lithium tantalate, and substrate materials such as compound semiconductor substrates, a polishing platen, and the like. The present invention relates to a polishing method using the same.

[0002]

2. Description of the Related Art Conventionally, silicon wafers, oxide substrates,
In the polishing process of a substrate material such as a compound semiconductor substrate, a non-woven fabric type or a swab is prepared by continuously flowing a polishing liquid prepared by mixing free abrasive grains such as colloidal silica with a chemical such as potassium hydroxide on the surface of the substrate material or the like. Finished by polishing with a polishing pad such as Ade type,
For example, JP-A-5-154760, JP-A-7-32659
No. 7 discloses that a silicon wafer is polished using various polishing agents and polishing cloths. However, in the case of using such a method, a large amount of free abrasive grains is used, so that a polishing waste liquid containing a large amount of free abrasive grains is generated. It was hoped that it would be improved in consideration of the effects of the above. Further, in the polishing process, the performance of the polishing cloth such as clogging is deteriorated in a short time, so that it is necessary to replace the polishing cloth with a new one, and there is a problem in terms of efficiency of the polishing process.

[0003]

As described above, when the polishing is performed by the conventional method, there is a problem that a polishing liquid containing a large amount of free abrasive grains such as colloidal silica is discarded. The present invention has been made in view of the above problems. The aim is to reduce the problem of waste liquid by using a polishing liquid that does not contain such free abrasive grains in the process of polishing substrate materials such as silicon wafers, oxide substrates, and compound semiconductor substrates. To provide a molded body for polishing that can achieve the same level of polishing finish as the method described above, and that can also improve the efficiency of polishing work by having durability in the polishing process, a polishing platen incorporating the same, and a polishing method using the same. It is in.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, when forming a molded body for polishing, a silica powder as a raw material was molded and processed to have a specific shape. The following knowledge is obtained by obtaining a molded body for polishing having the following, incorporating this into a polishing platen and polishing a substrate material or the like (hereinafter, the substrate material or the like to be polished in the present invention is referred to as a “material to be polished”). Was found to be an excellent point.

1) During polishing, the surface of the molded article for polishing is
Since the surface is roughened by the ultrafine powder of silica, which is the raw material, and the material to be polished comes into direct contact, polishing of the substrate material and the like is performed using a polishing liquid that does not contain free abrasive grains such as colloidal silica. It can be applied to the processing process, and at that time, the particles of the molded body are very little dropped,
The problem of waste liquid is reduced.

2) Since the strength of the molded article for polishing is high, and the shape thereof is chamfered at the boundary with the material to be polished, damage to the molded article for polishing is extremely reduced even in the polishing process, and therefore, for a long period of time. Polishing can be performed without replacement.

[0007] 3) The finish of the polished material is equal to or more than that of the conventional method using a polishing cloth, and the polishing rate is equal to or more than that of the conventional method. .

4) Even when an abrasive containing free abrasive grains is used, the polishing rate is improved at a concentration of free abrasive grains which is lower than that of the conventional method.

[0009] In particular, by chamfering the shape of the molded article for polishing, chipping, cracking and other damage during the polishing process of the molded article mainly composed of silica are extremely reduced, so that the efficiency of the polishing operation can be improved. The inventors have found that the present invention has been completed.

[0010] That is, the present invention relates to a molded article for polishing in which a boundary portion between a polishing surface of the molded article for polishing and a surface in the thickness direction of the molded article for polishing is chamfered. The present invention relates to a polishing surface plate obtained by arranging one or a plurality of compacts and a polishing method using the same.

Hereinafter, the present invention will be described in detail with reference to the drawings.

The composition of the molded article for polishing according to the present invention mainly comprises silica. Here, mainly silica substantially means a silica component in the silica powder used as a raw material of the molded article for polishing of the present invention, and is used when producing a molded article using the silica powder. The additive such as the binder finally disappears by a process such as firing or sintering. Therefore, the silica component in the abrasive compact has a composition based on the component of the silica powder that is the raw material. In addition, for additives such as a binder used when manufacturing a molded article, for example, the presence or absence thereof can be confirmed by an analytical method such as suggestive thermogravimetric analysis, and is usually up to about 500 to 600 ° C. When heated, additives such as binders almost disappear.

Further, the composition of the silica powder as a raw material is mainly silica, that is, a silica component having a total amount of 9%.
Those having 0% by weight or more are preferably used.
Examples of the type include dry silica and wet silica. The silica component as used herein means a silica content. The silica component, impurities, and ignition loss after heating the silica powder at 105 ° C. for 2 hours.
loss (hereinafter referred to as "Ig loss") is the weight percentage of the silica component when the total amount is the total amount. Therefore, excluding the loss on ignition, the raw material silica powder is 97% by weight or more of the total amount as the silica component. When the silica component falls below the above range, when the polishing is performed using the finally obtained molded body for polishing, the material to be polished may be contaminated by impurities in the molded body for polishing. In some cases, defects occur in the material to be polished during polishing.

Further, the shape of the molded article for polishing having such a composition may be a boundary portion between a polishing surface of the molded article for polishing which comes into contact with a material to be polished and a surface in a thickness direction of the molded article for polishing. Must be chamfered.

Here, the meaning of chamfering at the boundary between the polished surface in contact with the material to be polished and the surface in the thickness direction in the present specification will be described with reference to FIG.

Normally, in the polishing method using the polishing compact, the polishing is performed at the contact point B (point on the polishing surface of the polishing compact) between the polishing compact and the material to be polished shown in FIG. Contact between the molded body for use and the material to be polished starts. Here, a tangent in the intrusion direction of the material to be polished at the contact point B (tangent 1 shown in FIG. 1) and a tangent in the thickness direction of the molded body for polishing at the contact point B (tangent 2 shown in FIG. 1). The angle formed is angle A. The magnitude of the angle A is based on the tangent 1 in the direction of entry of the material to be polished at the contact point B in FIG.
The above value is counterclockwise. When the angle A is used, the boundary portion between the polishing surface in contact with the material to be polished of the polishing compact and the surface in the thickness direction of the polishing compact is chamfered when the angle A is always greater than 90 °. It is to be smaller. Here, a polishing molded body having a rounded end is also included in the scope of the present invention.

As can be seen from FIG. 1, this angle A can only take a value within the range of more than 0 ° and less than 180 °.
That is, if the angle A is 0 ° or 180 °, it means a molded body for polishing having no thickness, which means that it does not exist. In the molded article for polishing of the present invention, the angle A is not particularly limited as long as it is in a range of more than 0 ° and less than 90 °, but in order to further enhance the durability of the molded article for polishing in the polishing process. Is 4
It is more preferable that the angle is 0 ° or more and 80 ° or less. Of course, if the angle is smaller than 40 °, there is no problem in the polishing operation, but it is not practical because the area of the contact surface becomes smaller and the polishing efficiency is lowered. On the other hand, if the angle exceeds 80 °, the effect of chamfering at the boundary between the polished surface of the molded article for polishing and the surface in the thickness direction of the molded article for polishing may be reduced. Also, the angle A
If the angle is not less than 90 ° and less than 180 °, breakage during polishing of the molded article for polishing tends to become remarkable, which is not preferable.

If the boundary portion is not chamfered, the contact between the material to be polished and the compact for polishing at the contact point B in FIG. 1 is too strong in the polishing process. It is easy for the molded body for polishing to be chipped due to too large a resistance at the time or a frictional resistance due to the friction between the two during polishing. A part of the damaged abrasive compact cannot be brought into contact with the material to be polished, and the polishing efficiency is reduced without being involved in the polishing. If a molded article for polishing that is widely damaged such as more than 10% or more than 10% of the area of the contact surface is directly used in the polishing process, the material to be polished may be damaged, which is not preferable. .

The method of chamfering is not particularly limited as long as it has the shape of the above-mentioned abrasive compact. For example, a silica compact is obtained from silica powder by press molding, and finally the abrasive compact is formed. When obtaining a compact, a method of obtaining a chamfered compact by elaborating the shape of a press-molding die so as to be the shape of the polishing compact of the present invention, a molded silica compact or firing this Examples of the method include a method of performing chamfering by performing mechanical processing such as grinding processing and sand paper processing on the end portion of the obtained molded body for polishing.

In order to make the molded article for polishing of the present invention more suitable for polishing, it is preferable to consider the bulk density, the BET specific surface area, and the average particle size of the molded article for polishing as physical properties.

Specifically, the bulk density range of the molded article for polishing is 0.2 g / cm 2 in order to maintain the shape of the molded article for polishing and obtain a smooth surface of the material to be polished.
³ or more and 1.5 g / cm ³ or less, more preferably 0.2 g / cm ³
/ Cm ³ or more and 1.0 g / cm ³ or less. When the bulk density is below 0.2 g / cm ^3, may durability is poor enough shape retention not maintain its shape as well as decrease, the surface of the polishing object to exceed 1.5 g / cm ³ May not be negligible, and a smooth surface may not be obtained.

The BET specific surface area of the molded article for polishing is preferably from 10 to 400 m ² / g, more preferably from 1 to 400 m ² / g.
It is preferably from 5 to 100 m ² / g. If the BET specific surface area exceeds 400 m ² / g, the shape retention of the molded article may be deteriorated so that the shape of the molded article cannot be maintained. If the BET specific surface area is less than 10 m ² / g, defects on the surface of the material to be polished cannot be ignored and the surface is smooth. It may be difficult to obtain a proper surface.

The average particle size of the abrasive compact is preferably in the range of 0.001 μm to 0.5 μm in order to facilitate molding into a porous body and obtain a smooth surface of the material to be polished. When the average particle size is smaller than 0.001 μm, the primary particle size of the raw material powder may be smaller than 0.001 μm, and it may be extremely difficult to form a porous body.

Next, a method of assembling the molded body for polishing as a polishing platen and performing polishing using the platen will be described.

First, a polishing platen is formed by using a polishing compact and a polishing accessory part. Here, ancillary parts are structures having various shapes such as a flat plate, a convex plate, and a concave plate which constitute a polishing platen. The polishing platen is formed by arranging and fixing by various methods as described above.
As a fixing method of both, any method can be used without particular limitation as long as the method can achieve the object of the present invention, such as a method of bonding and fixing using an adhesive, or a method of forming irregularities on ancillary parts and embedding in the fixing place. Can be.

The number of the abrasive compacts used for fixing the abrasive compacts to the auxiliary parts for polishing may be one or more, more preferably a plurality. This is because 1) the polishing rate is improved by appropriately discharging the polishing liquid used in the polishing process during polishing. Therefore, when the polishing platen is formed by using a plurality of polishing compacts, the polishing liquid can be discharged from gaps between the polishing compacts. When one is used, it is preferable to provide an appropriate groove structure capable of discharging the polishing liquid on the side of the polishing surface of the molded body. 2) When a polishing platen is formed by using a plurality of polishing compacts, the contact with the material to be polished is improved, and the polishing can be performed efficiently without biasing the polishing rate over the entire surface of the material to be polished. Become like

Further, when a plurality of polishing compacts arranged on the polishing platen are used, the physical properties such as the shape, bulk density, BET specific surface area and average particle diameter of each polishing compact are the same. May also be different.

The shape of the shaped body for polishing used in the polishing platen of the present invention is such that the boundary between the polished surface of the shaped body for polishing that comes into contact with the material to be polished and the surface in the thickness direction of the shaped body for polishing is used. It is not particularly limited as long as it is chamfered,
For example, columnar pellets as shown in FIGS. 1 and 2,
Examples thereof include prisms such as quadrangular prisms and triangular prisms. The size is not particularly limited as long as it is within a range usually used, and is determined according to the size of an accessory part for incorporating a molded body for polishing in a polishing table. As for the thickness of the abrasive compact, when consumption of abrasive compact which is used during polishing is high, h ₁ in h _1, h ₂ shown in Figure 1 -
It is preferable that the value of h ₂ be large, and h ₂ may be 0. Further, the value of h ₁ -h ₂ may be changed according to the thickness of the material to be polished.

Usually, the size of ancillary parts is 2
Those having a size of about 00 mm or more and 800 mm or less are used. However, when one polishing molded body is used, it is only necessary that the size is slightly smaller than the size of the accessory component to be used and can be accommodated therein. When a plurality of abrasive compacts are used, each side has a length of 5 mm or more and 10 mm or more, depending on the number used.
It is practically preferable that the size be within the range of the corner of 0 mm or less. For example, in the case of columnar pellets,
00 mm or less, 5 mm or more and 100 for square columnar pellets
mm or less. Even when one side is smaller than this range, it has a sufficient function as a polishing table, but it may not be practical because the number of arrangements is very large. Although it has a sufficient function as a board, the effect of arranging a plurality of abrasive compacts may be reduced. Also,
As for the size, if a groove is formed on the side of the polishing surface of the molded article for polishing, the preferable size can be increased.

Further, the thickness of the molded article for polishing, that is, the length in the direction perpendicular to the accessory parts for polishing is not particularly limited, but is preferably in the range of 3 mm to 20 mm. . Even when the thickness deviates from this range, it has a sufficient function as a polishing surface plate, but this range is preferable in consideration of practicality. Here, the thickness of the molded article for polishing is a value corresponding to the maximum height of the molded article for polishing from the auxiliary component to which the molded article for polishing is fixed.

When a material to be polished is polished by using a polishing platen into which the chamfered molded body for polishing is incorporated, any plate used in the polishing process may be used as the platen. There are no particular restrictions on the polishing conditions, the use of a polishing liquid, or the like. For example, when a polishing liquid is used, use of a potassium hydroxide aqueous solution or the like can be exemplified. Here, the surface plate is used for polishing by directly contacting the material to be polished, has sufficient strength in the polishing process, and has a performance capable of polishing the material to be polished. I just need to. Therefore, the shape may have not only the same shape as the material to be polished but also a non-planar shape if necessary.
For example, as its shape, a flat plate, a disk, a ring,
A cylindrical shape or the like can be given.

In addition, since the polishing method of the present invention does not use a polishing cloth, interruption of the polishing operation due to replacement of the polishing cloth due to deterioration in the performance of the polishing cloth as seen in the conventional method during polishing is not required. The use of the abrasive compact improves the durability of the abrasive compact, and the frequency of replacement can be extremely reduced, so that the polishing operation can be made more efficient. Furthermore, the polishing waste liquid containing free abrasive grains generated by the conventional method using an abrasive can be polished without using free abrasive grains by using the molded article for polishing according to the present invention. Free abrasive grains in the waste liquid are eliminated, and the problem of waste liquid treatment is reduced. Even when a polishing liquid containing free abrasive grains is used, the problem of waste liquid treatment can be reduced because polishing can be performed with a concentration of free abrasive grains which is lower than that of the conventional method. Naturally, polishing can also be performed using a polishing liquid containing free abrasive grains at the same level as in a conventional polishing method using a polishing cloth.

The polishing platen made of the polishing compact of the present invention can be used as a silicon wafer, a compound semiconductor substrate such as gallium phosphide or gallium arsenide, lithium niobate, or the like.
Oxide substrates such as lithium tantalate and lithium borate,
It can be used for polishing a substrate material such as a quartz glass substrate, quartz glass, a metal material, and a stone material such as a building.

[0034]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In addition, each evaluation was implemented by the method shown below.

-Bulk Density-A flat sample having a size of 100 mm x 100 mm x 15 mm (thickness) was prepared and used as a sample. This sample was calculated from the weight measured with an electronic balance and the shape and dimensions measured with a micrometer.

-Powder bulk density- According to the stationary method of the apparent density test method of JIS-K-5101, the powder is dispersed and dropped through a sieve having an opening of 0.50 mm and received in a 30.0 ml stainless steel cylinder. At the peak, it was rubbed off with a linear spatula, the weight in the cylinder was measured, and it was determined by the following equation (1).

E = W / 30 (1) where E is powder bulk density (unit: g / ml), W is powder weight in cylinder (unit: g), and 30 is volume in cylinder (unit: ml). Yes, the unit of powder bulk density is arbitrarily converted. In this specification, the measured apparent density is described as powder bulk density.

[Average Particle Diameter] A part of the abrasive compact was subjected to scanning electron microscope ISI-13.
Observed at 0 (manufactured by Akashi Seisakusho) and determined by the intercept method taking into account only the silica particle portion.

-BET specific surface area-After grinding the compact for polishing, MONOSORB (US KU
(Antachrom Co., Ltd.) using the BET one-point method.

[Average Particle Diameter of Powder] A sample of ultra-fine silica powder was prepared using COULTER LS
130 (manufactured by COULTER ELECTRONICS) using a liquid module. Measurements are on a volume basis.

Polishing Test A test piece of the molded body for polishing shown in FIG. 4 and Table 1 having a diameter of 25 mm and a thickness of 10 mm was prepared and mounted on a rotating platen (360 mm in diameter) of a high-speed lens polishing apparatus. The body surface was flattened. The platen was rotated at a rotation speed of 100 rpm under a predetermined processing pressure of the material to be polished on the platen, and six pieces of lithium tantalate substrate having a diameter of 3 inches were simultaneously used as the material to be polished, and commercially available colloidal silica (Fujimi Incorporated) was used. (Compol80, manufactured by Dodo Co., Ltd.) with silica (silicon dioxide)
Polishing liquid prepared to have a content of 8% by weight (liquid temperature: 2
5 ° C., pH = 12) 100 ml of polishing solution using the solution
The polishing was carried out while dripping at a rate of / min. After polishing, the surface of the lithium tantalate was examined under a microscope (OLYMPU).
SH, model: BH-2). Upon evaluation,
The case where the surface was extremely smooth and free of scratches and the like was evaluated as ○, and the case where the surface was not smooth and could not be polished was evaluated as ×. The polishing rate was calculated by measuring the thickness of the lithium tantalate substrate before and after the polishing test with a dial gauge.

-Surface Accuracy- The surface accuracy of the material to be polished after the polishing treatment was evaluated using a universal surface shape measuring instrument SE-3C (manufactured by Kosaka Laboratories). The evaluation was performed under the conditions of a center line average roughness (Ra) and a maximum height (Rmax) of a cutoff value of 0.8 mm or more and a measurement length of 2.5 mm. Here, Ra means the center line average roughness, and a portion of the measured length (represented by L) is extracted from the roughness curve in the direction of the center line, and the center line of the extracted portion is defined by the X axis and the vertical axis. The direction of magnification is the Y axis, and the roughness curve is y = f
When expressed by (x), the value obtained by the following equation (2) is expressed in units of micrometers (μm).

[0043]

(Equation 1)

Further, Rmax means the maximum height. When two straight lines parallel to a parallel line of a portion extracted by the reference length from the cross-sectional curve sandwich the extracted portion, the interval between the two straight lines is defined by the cross-sectional curve. Is measured in the direction of the vertical magnification, and this value is expressed in units of micrometers (μm).

-Durability of the molded body-The polishing test was continuously performed, the molded body was visually observed, and the presence or absence of breakage such as cracks, cracks, chips, etc. caused by contact with the material to be polished was observed. At the time of evaluation, the relationship between the number of damaged molded articles and the number of used molded articles after 30 hours of the polishing test was examined.

Examples 1 to 3 Wax-based emulsion (manufactured by Chukyo Yushi, Maxelon M) and stearic acid emulsion (manufactured by Chukyo Yushi, manufactured by Chukyo Yushi Co., Ltd.) were added to raw material powder of precipitated silica obtained by a wet method having the characteristics shown in Table 1. Cellosol 920) was prepared by mixing raw material powder: wax-based emulsion (in terms of solid content): stearic acid emulsion (in terms of solid content): water = 100: 17: 0.
The mixture was mixed at a weight ratio of 2: 408 to form a slurry. This slurry is spray-dried (Okawara Kakoki Co., Ltd., model:
The granulated powder was adjusted using LT-8), and water was sufficiently removed in a desiccator. The granulated powder was press-molded (pressure: 100 kg / cm ² ) using a hydraulic press to obtain a silica compact. 400 ° C, 1.5 kg / cm
^2. After degreasing under pressure using a pressure degreasing furnace (manufactured by Nemus) in nitrogen, a firing furnace (manufactured by Koyo Lindberg Co., model: 516)
By baking at 975 ° C. for 2 hours at 68), a molded article for polishing was obtained. The angle A of the abrasive compact was 65 ° in Example 1,
The angle is 40 ° in the second embodiment and 80 ° in the third embodiment. This was evaluated by the evaluation method described above. Table 2 shows, as the obtained results, the bulk density, BET specific surface area, average particle diameter of the silica molded body, the polishing test results using the obtained polishing plate, the measurement results such as surface accuracy, and the durability test results. Table 3
Shows the processing pressure, abrasive grain concentration and polishing rate in the polishing test.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

[Table 3]

Example 4 A wax-based emulsion (manufactured by Chukyo Yushi, Maxelon M) and a stearic acid emulsion (manufactured by Chukyo Yushi, Cellosel 920 having the properties shown in Table 1 were added to the raw material powder of precipitated silica obtained by the wet method. ) As raw material powder: wax-based emulsion (in terms of solid content): stearic acid emulsion (in terms of solid content): moisture = 100: 17: 0.
The mixture was mixed at a weight ratio of 2: 408 to form a slurry. This slurry is spray-dried (Okawara Kakoki Co., Ltd., model:
The granulated powder was adjusted using LT-8), and water was sufficiently removed in a desiccator. The granulated powder was press-molded (pressure: 100 kg / cm ² ) using a hydraulic press to obtain a silica compact. This was kept at 400 ° C. for 2 hours in a firing furnace (manufactured by Koyo Lindberg, model: 51668),
The temperature was raised to 950 ° C. and kept for 2 hours to obtain a molded article for polishing. The angle A of the molded body for polishing is 65 °. This was evaluated in the same manner as in Example 1, and Table 2,
The results are shown in Table 3.

Comparative Examples 1 and 2 A wax-based emulsion (manufactured by Chukyo Yushi, Maxelon M) and a stearic acid emulsion (manufactured by Chukyo Yushi, manufactured by Chukyo Yushi Co., Ltd.) were added to the raw material powder of the precipitated silica obtained by the wet method having the characteristics shown in Table 1. Cellrosol 920) as a raw material powder: wax emulsion (in terms of solid content): stearic acid emulsion (in terms of solid content): moisture = 100: 17: 0.2:
The mixture was mixed at a weight ratio of 408 to form a slurry. This slurry is spray-dried (Okawara Kakoki, Model: LT
The granulated powder was adjusted using -8), and water was sufficiently removed in a desiccator. The granulated powder was press-molded (pressure: 100 kg / cm ² ) using a hydraulic press to obtain a silica compact. This was taken at 400 ° C., 1.5 kg / cm ² ,
After degreasing under pressure using a pressure degreasing furnace (manufactured by NEMS) in nitrogen, a firing furnace (manufactured by Koyo Lindberg Co., model: 5166)
By baking at 975 ° C. for 2 hours in 8), a molded body for polishing was obtained. The angle A of the abrasive compact was 90 ° in Comparative Example 1,
In Comparative Example 2, the angle is 100 °. This was evaluated in the same manner as in Example 1 and shown in Tables 2 and 3.

From the results of Examples 1 to 4 and Comparative Examples 1 and 2, the method of polishing using a polishing plate of the present invention in a method of polishing using a polishing platen made of a polishing product was carried out. Thus, it was found that breakage such as chipping due to contact between the polishing compact and the material to be polished during polishing can be significantly suppressed. It was also found that the polishing rate of the example can be polished more quickly than that of the comparative example.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a molded article for polishing according to the present invention.

FIG. 2 is a perspective view showing an example of a molded article for polishing according to the present invention.

FIG. 3 is an example of a layout appearance view of a molded body for polishing (columnar shape) in a polishing platen of the present invention.

FIG. 4 is a plan view of a cylindrical polishing compact used in Examples and Comparative Examples, and an angle A is a numerical value shown in each example.

[Explanation of symbols]

1 and 4 are commonly used. 1: A tangent line in the invasion direction of the material to be polished at the contact point B 2: A tangent line in the thickness direction at the contact point B 3: A molded body for polishing 4: An angle A 5: A cylindrical polishing plate incorporated in a polishing platen shaped body 6: supplementary to incorporate abrasive compact in abrasive plate parts D _1: the opposite side of the contact surface of the abrasive compact diameter D _2: the diameter of the contact surface of the abrasive compact D _3: polishing the width of the chamfered circumferential inclined portion of the use compacts h _1: thickness of abrasive compact h _2: thickness of the portion that is not chamfered abrasive compact

According to the present invention, a polishing waste liquid containing a large amount of free abrasive grains, which is found in the conventional method, is not generated during the polishing process. The substrate material such as can be polished, and in particular, it can suppress breakage such as chipping due to the contact between the polished compact and the material to be polished during the polishing process, and efficiently perform the polishing process. Therefore, it is useful for a polishing process of a substrate material such as a silicon wafer and an oxide substrate.

Claims (4)

[Claims] In a molded article for polishing mainly composed of silica (silicon dioxide), a boundary between a polished surface of the molded article for polishing in contact with a material to be polished and a surface in a thickness direction of the molded article for polishing is formed. A molded article for polishing, characterized by being chamfered. 2. The polishing molded body has a bulk density of 0.2 to 1.5.
g / cm ³ and a BET specific surface area of 10 to 400 m ² /
g. and the average particle diameter is 0.001 to 0.5 μm. 3. A polishing surface plate comprising the polishing molded body according to claim 1 and an accessory part. 4. A polishing method comprising polishing a material to be polished using the polishing platen according to claim 3.