JPH1080860A - Material for grinding tool and grinding surface plate using the material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish a high hardness without carrying out a quick cooling and quick heating process and the like, in a material for grinding roll used for a grinding surface plate and the like. SOLUTION: This material for grinding tool consists of an iron material containing C 0.2wt.% or more and less than 0.8wt.%; Si 1wt.% or more and 7wt.% or less; Ni 4wt.% or more and 7wt.% or less; Mn 1wt.% or less (more then 0wt.%); and Cr 1wt.% or less (more than 0wt.%); or an iron material containing C less than 0.2wt.% (more than 0wt.%); So 1.5wt.% or more and 3.5wt.% or less; Ni 7wt.% or more and 17wt.% or less; Mn 1wt.% or less (more than 0wt.%); and Cr 2wt.% or more and 4wt.% or less. There iron materials have the hardness of Hv 250 or higher. A grinding surface plate 1 consists of the above materials for grinding tool.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for a polishing tool used for a polishing platen used for lapping a semiconductor substrate, an oxide single crystal substrate, a quartz glass or the like, and a polishing platen using the same. .

[0002]

2. Description of the Related Art Generally, Si wafers, GaAs, InP
Etc., a semiconductor substrate such as LiTaO _3, an oxide single crystal substrate,
In lapping of quartz photomasks, etc., slurry-like abrasive grains are supplied between the upper and lower platens and the workpiece,
A method of removing the required amount of shaving allowance from the workpiece with the cutting edge of the abrasive using the rotating motion of the surface plate while applying the processing pressure, and thereby transferring the flatness of the surface plate to the workpiece. Has been adopted. Such polishing is not limited to Si wafers and the like, and is often used for the purpose of flattening the surface of a workpiece such as glass, jewelry, metal, and ceramics. With the rapid increase in the degree of integration, flatness has become more and more strictly required, and it has become important to maintain the flatness of a polishing platen used for lapping.

A lapping plate for a Si wafer is polished by abrasive grains in the same manner as a Si wafer. However, the rotation of the platen increases the distribution of the amount of abrasive particles and the angular velocity of rotation on the outer peripheral side. The amount of polishing on the outer peripheral side of the board increases. That is, the flatness of the polishing table changes with the elapse of the polishing operation time, and the polishing surface of the lower table has a tendency to change so as to be convex upward.

As described above, the flatness of the polishing platen tends to change with the lapse of polishing operation time. However, as described above, as the flatness requirement of a Si wafer or the like increases,
Since it has become an important technical issue to keep the flatness change of the polishing platen low, the conventional polishing platen for Si wafers reverses the conventional wisdom, and the polishing plate made of a material with hardness of Hv 200 or more A board has been proposed (see JP-A-60-59850 and JP-A-5-307069), and is actually used for polishing a Si wafer.

[0005] As described above, a high hardness polishing platen has a hard structure (a quenching heat treatment after a solution treatment such as a quenching / tempering treatment, an austempering treatment and a normalizing treatment) of a base structure of a cast iron-based material. Martensite organization,
(Baitnite structure, pearlite structure, etc.) have been put to practical use. On the other hand, the size of the Si wafer is
The mainstay is 8 inches (about 203 mm), and wafers larger than 12 inches are under development. Such S
With the increase in the diameter of i-wafers, the polishing platen has tended to become larger and larger, and a diameter of 1.5 to 2.0 m (thickness of 40 to 60 mm) has become standard. With such a large polishing table,
If the hardness is increased by the rapid cooling heat treatment at a high cooling rate as described above, problems such as remarkable shape deformation and difficulty in obtaining a uniform structure are caused.

[0006]

As described above, Hv 2
Since a polishing surface plate having a high hardness of at least 00 can suppress a change in flatness to a low level, it is expected to be used for a lapping operation of a semiconductor wafer, for which there is an increasing demand for flatness. However, with respect to a polishing platen that has been increased in size due to an increase in the diameter of a semiconductor wafer, etc., it is difficult to suppress the deformation in the quenching heat treatment for obtaining the hardness as described above or to make the structure uniform. The situation is coming.

[0007] For these reasons, it has been an issue to achieve high hardness without performing quenching heat treatment especially in a large-sized polishing platen. Further, it is also required that the polishing platen material for semiconductor wafers has almost no hard precipitates such as coarse carbides that cause scratches on the wafer, and also has excellent hardness uniformity.

The present invention has been made in order to solve such problems, and a polishing tool material which has achieved high hardness without performing quenching heat treatment and the like, a polishing platen using the same, and a coarse plate. It is an object of the present invention to provide a material for a polishing tool which has almost no hard precipitates and has excellent hardness uniformity, and a polishing platen using the same.

[0009]

Means for Solving the Problems A first polishing tool material according to the present invention comprises C of 0.2% by weight or more and less than 0.8% by weight.
1 wt% to 7 wt% Si, 4 wt% to 7 wt%
% Of Ni, 1% by weight or less of Mn, and 1% by weight or less of Cr, wherein the iron-based material has a hardness of Hv 250 or more.

The material for the second polishing tool is 0.2% by weight.
% Of C, 1.5 wt% or more and 3.5 wt% or less of Si, 7
Weight% or more and 17 weight% or less Ni, 1 weight% or less Mn,
And 4% by weight or less of an iron-based material containing Cr, wherein the iron-based material has a hardness of Hv 250 or more.

The polishing platen of the present invention is characterized by being made of the above-mentioned first or second polishing tool material of the present invention.

The polishing tool material of the present invention has a composition in which a martensite structure appears in an as cast structure based on a composition containing a relatively high concentration of Ni. And a high hardness of Hv 250 or more can be achieved. That is, it is possible to eliminate deformation and non-uniformity of the structure due to the quenching heat treatment, and it is possible to improve shape accuracy and uniformity of hardness, for example, even with a large polishing platen. Further, since the material for a polishing tool of the present invention has a carbon composition that does not cause the appearance of a graphite structure, it is suitable for polishing a very fragile compound semiconductor such as GaAs or InP or lapping a Si wafer with fine abrasive grains.

[0013]

Embodiments of the present invention will be described below.

The first polishing tool material of the present invention basically comprises C of 0.2% by weight or more and less than 0.8% by weight, and 1% by weight or more.
7% by weight or less of Si, 4% by weight or more and 7% by weight or less of N
i, an iron-based material containing 1% by weight or less of Mn and 1% by weight or less of Cr, with the balance substantially consisting of Fe and having substantially no graphite structure.

Further, the second polishing tool material of the present invention comprises:
As a substrate, less than 0.2% by weight of C, 1.5% to 3.5% by weight of Si, 7% to 17% by weight of Ni,
Less than 4% by weight of Mn and less than 4% by weight of Cr,
The balance is substantially composed of Fe, and is composed of an iron-based material having substantially no graphite structure.

Here, in the lapping or the like of a Si wafer, a polishing plate having a graphite structure serving as a supplementary site for lapping abrasive grains is usually used.
Since compound semiconductors such as s and InP are very brittle materials, the processing load of lapping is low, and polishing proceeds while the abrasive grains roll on the surface of the workpiece. In such lapping, a graphite structure as a supplementary site for abrasive grains is not always necessary. Conversely, if a large amount of graphite structure is present, polishing debris is captured by the graphite and causes scratches on the workpiece. The same applies to the finish lapping (relapping) of a Si wafer using fine abrasive grains.

As shown in FIG. 1, the first and second polishing tool materials have a carbon content within a range of solid solution carbon, and as described above, a compound semiconductor such as GaAs or InP or fine abrasive particles. On the other hand, in the finish lapping of the Si wafer using, a metal structure basically having no graphite structure serving as a supplementary site for abrasive grains is obtained. In order to realize a hardness of Hv 250 or more in an iron-based material having a composition in which such a graphite structure does not basically appear, for example, without performing a quenching heat treatment (quenching, etc.) from a temperature of 1073 K or more. In addition, the composition is such that a martensite structure appears in a metal structure in an as cast state (casting structure).

Hereinafter, the iron-based material composition of the first polishing tool material will be described in detail. C (carbon) is an element for obtaining high strength and high hardness in an iron-based material. When the C content is 0.8% by weight or more, a graphite structure appears as shown in FIG. Therefore, the C content is less than 0.8% by weight. Further, when the C content is less than 0.2% by weight, the other element compositions for causing a martensitic structure to appear, that is, the contents of Ni, Si, Cr, etc., are different, so that the first polishing tool material is not used. Has a C content of 0.2
% By weight or more. In other words, the first polishing tool material has a component composition for causing a martensitic structure to appear when the C content is 0.2% by weight or more and less than 0.8% by weight.

Si (silicon) is a component that contributes to the improvement of castability. When the Si content is less than 1.0% by weight, shrinkage cavities and the like are liable to occur due to a decrease in castability. Also,
Si is an element that affects the Cr equivalent, which will be described later. If the Si content is too large, the area ratio of the martensite structure is reduced or the martensite structure cannot be formed, so the content is 7.0% by weight. The following is assumed.
When Si is contained in an amount of 7.0% by weight or more, an intermetallic compound (M ₃ Si: M is Fe or Ni) is formed with an element such as Fe or Ni, which causes a decrease in mechanical properties such as hardness and strength.
From this point as well, the Si content is in the range of 1.0 to 7.0% by weight.

Ni forms a wide range of solid solution with Fe up to about 76% by weight, and as is known from the structure diagram of Schaeffler in FIG. 2, the Ni content (equivalent) and the Cr content (equivalent) in Fe are From this relationship, the phase structure of the base structure, for example, the ratio of the martensite structure to the austenite structure is determined. Schaeffl
The Ni equivalent and the Cr equivalent in the er organization chart are represented by the following equations. However, in the actual casting structure, segregation or the like occurs during solidification, and the region of the martensite structure tends to be slightly wider than the structure diagram of Schaeffler. Ni equivalent weight (% by weight) = Ni weight% + 30 × C weight% + 0.5 ×
Mn wt% Cr equivalent (wt%) = Cr wt% + 1.5 × Si wt% + M
As can be seen from FIG. 2, the iron-based material as the first polishing tool material is made of metal in an as cast state in consideration of the C content, the Si content, and the Cr and Mn contents described below. The Ni content is such that a martensitic structure can appear in the structure, that is, the Ni content is not less than 4% by weight and not more than 7% by weight. The martensite structure has a high hardness, and can realize a hardness of Hv 250 or more.

Mn has the effect of improving the mechanical strength, but if the content is too large, the formation of carbides cannot be avoided, and since it acts as an austenitizing element, the upper limit of the content is 1.0% by weight. And Even when Mn is added in a small amount, the effect according to the addition amount is exhibited. Therefore, the content of Mn is in the range of 0 to 1.0% by weight (however, 0 is not included), but the effect of Mn addition is 0.2% by weight. % Is noticeable.

Cr is a component that contributes to improvement of corrosion resistance and stabilization of the martensite phase. However, if the content of Cr exceeds 1% by weight, formation of coarse carbides cannot be avoided. The content is within the range of 1% by weight or less. Even if a small amount of Cr is added, the effect according to the amount of addition is exhibited. Therefore, the content of Cr is set in the range of 0 to 1.0% by weight, but the effect of the addition of Cr becomes remarkable from about 0.2% by weight.

The first polishing tool material is based on the above-mentioned iron-based material composition. However, as long as coarse hard precipitates are not formed, Mo or less of 1.0% by weight or less is used.
It may contain Nb, Ti, V, Al, Cu and the like.

Next, the details of the iron-based material composition of the second polishing tool material will be described. The second polishing tool material is
Containing at least C (carbon) necessary for casting,
When the C content is less than 0.2% by weight (but not including 0), it has a component composition for producing a martensitic structure. First, Si (silicon) is added in an amount of 1.5 to 3.5% by weight. It is contained in the range. Si is a component that contributes to the improvement of castability as described above, but is an element that also affects the Cr equivalent, so that a martensitic structure appears in the ascast structure. Shall be contained within the range.

As described above, Ni is an element that greatly influences the phase structure of the base structure, for example, the determination of the ratio between the martensitic structure and the austenite structure. Depending on the C content of less than 0.2% by weight, Ni has an Ni that allows a martensitic structure to appear in the metal structure in a state
The content, that is, the Ni content of 7% by weight or more and 17% by weight or less. The martensite structure has a high hardness, and can realize a hardness of Hv 250 or more.

Mn has the effect of improving the mechanical strength, but if the content is too large, the formation of carbides cannot be avoided, and since it acts as an austenitizing element, its content is reduced by the first polishing tool. As well as materials
1.0% by weight or less (excluding 0). The effect of the addition of Mn is significant from about 0.2% by weight.

Cr is a component that contributes to the improvement of corrosion resistance and stabilization of the martensite phase, and is also an element that affects the phase structure of the matrix structure. It stabilizes the martensite structure in the metal structure in an as cast state. 2 so that it can appear in
It is preferred that the content be at least 10% by weight. However, 0.2 weight
%, The Cr content is less than 4%.
If the content exceeds 10% by weight, coarse carbides may be precipitated, so the content is limited to 4% by weight or less.

The second polishing tool material is based on the above-mentioned iron-based material composition. However, as long as coarse hard precipitates are not formed, Mo, 1.0 wt% or less is used.
It may contain Nb, Ti, V, Al, Cu and the like.

As described above, the first and second embodiments of the present invention
The polishing tool material of (1) has a base structure in which a martensite structure appears in an as cast structure, and thereby achieves a hardness of Hv 250 or more in an as cast state without performing quenching treatment. As described above, by realizing the hardness of Hv 250 or more in the ascast state, it is possible to avoid problems such as deformation and non-uniform structure due to the quenching heat treatment.

It is preferable that the composition of each component, the presence or absence of heat treatment described later, and the like be set so that the martensite structure in the metal structure becomes 30% or more in area ratio. The area ratio occupied by a more preferable martensite structure is 60% or more.
That is, by setting appropriate Ni equivalent and Cr equivalent, 30% or more (area ratio) of the base structure is made to be a martensite structure, and when it exceeds 70%, the hardness is higher than that of an iron-based material mainly composed of austenite structure. Wear resistance) and rigidity (elastic modulus) can be increased, and a hardness of Hv 250 or more can be realized with good reproducibility. The martensite structure can also be increased by an annealing process or a tempering process after casting, as described in detail later. Further, the martensite structure has a lower coefficient of thermal expansion and lower thermal expansion than the austenitic structure, and thus contributes to the suppression of thermal deformation of the polishing tool material. When the polishing tool material of the present invention is applied to a polishing platen, suppression of thermal deformation leads to improvement of polishing accuracy.

Here, even if an iron-based material having the above-described composition is used, if quenching (chiller) or the like is used to select a relatively rapidly solidified manufacturing condition during casting, as cas
In the state of t, a residual austenite structure may be formed. In such a case, after the above-mentioned iron-based material for a polishing tool, specifically, a polishing platen or the like made of this material for a polishing tool, once subjected to a solution treatment at a temperature of 1073 to 1223K, A martensite structure free of retained austenite can be obtained by performing an annealing treatment of cooling to room temperature at a slow cooling rate of about air cooling or lower, or a tempering treatment at a temperature of 573 to 973K. Further, the retained austenite can be decomposed into martensite by performing a sub-zero treatment for maintaining the temperature at 193 K or less for a certain period of time. Since the elongation of the martensite structure is almost zero, it is possible to prevent the generation of burrs on the surface plate and continuous polishing debris during the polishing operation, and it is possible to prevent the generation of scratches on the surface of the workpiece. .

The cooling rate after the above solution treatment is the first
For example, the material for the polishing tool may be cooled at 50 K / h or less (annealed at 20 K / h or less), while the material for the second polishing tool may be cooled at 20 K / h or less as in the case of furnace cooling. When gradual cooling is performed, carbides M ₂₃ C ₆ are formed at the grain boundaries of the metallographic structure, and the carbides at the grain boundaries drop off as the lapping progresses, causing scratches on the workpiece. It is preferable that It is also effective to perform a tempering treatment at a temperature in the range of 623 to 723K to decompose retained austenite.

The above-described annealing treatment and tempering treatment are effective for adjusting the hardness and homogenizing the structure, distortion, etc.
It shall be implemented as necessary. For example, the polishing tool material of the present invention may have an excessively high hardness in an as cast state depending on the composition, and the workability of the polishing tool material itself may decrease, but annealing under the conditions described above. By performing the treatment or the tempering treatment, particularly the tempering treatment, the workability of the polishing tool material itself can be improved while maintaining the hardness of Hv 250 or more.

The material for a polishing tool as described above is used, for example, as a constituent material of a polishing platen. FIG. 3 is a diagram showing a configuration of a polishing platen according to an embodiment of the present invention. The polishing platen 1 shown in FIG.
Of a polishing tool material. Polishing surface plate 1
A grid-like slit 2 is formed on the surface (polishing surface), and an abrasive supply hole 3 is provided in the center. In addition, the grid-like slit 2 is required to secure the accuracy of the polished surface.
It is usually formed before the shape processing of the polishing platen 1. Since the polishing platen of the above-described embodiment is made of the first or second polishing tool material of the present invention having a martensitic structure in an as cast structure, Hv 250 in an as cast state without a quenching heat treatment. The above hardness can be realized. Therefore, even with a large polishing platen having a diameter of, for example, 1.2 to 2.0 m, it is possible to eliminate deformation, non-uniform structure, and the like due to rapid cooling heat treatment. Avoiding the deformation caused by the quenching heat treatment contributes to a reduction in the processing cost for imparting the shape of the polishing platen and an increase in the service life due to securing the shape (particularly the depth) of the grid-like slit 2. Further, the manufacturing cost and the number of manufacturing steps of the polishing platen 1 can be reduced by not performing the quenching heat treatment.

Further, since the hardness of Hv 250 or more is realized without performing quenching heat treatment, the structure and hardness of the polishing platen 1 can be made uniform, and hard precipitates such as coarse carbides can be obtained. Since the composition does not cause cracking, the processing accuracy of a semiconductor substrate or the like can be improved, and the occurrence of scratches or the like can be prevented. The uniformity of the structure and the hardness can be further improved by performing the above-described tempering treatment or the like. The polishing platen 1 described above is used for surface processing of various workpieces such as a semiconductor substrate such as a Si wafer, GaAs, and InP, an oxide single crystal substrate such as LiTaO ₃ , a quartz photomask, glass, jewelry, metal, and ceramics ( Surface flattening process), but in particular, lapping of compound semiconductors such as GaAs or InP or the like using fine abrasive grains, where graphite structure causes scratches and the like.
It is suitable for finishing lapping of a wafer.

The material for the polishing tool of the present invention is not limited to the above-mentioned polishing table, but can be effectively used as a constituent material of a correction jig for the polishing table, a fixing jig for a workpiece, and the like. is there.

[0037]

Next, specific examples of the present invention will be described.

Example 1 A cast iron having the composition shown in Table 1 was cast, and the casting had an outer diameter of 1400 m.
The polishing platen 1 shown in FIG. 1 having a m of 400 mm in inner diameter and a thickness of 60 mm was produced. The processing of a grid-like slit 2 with a width of 2 mm, a depth of 15 mm and a forming pitch of 40 mm and an abrasive supply hole 3 with a diameter of 8 mm is as
It was processed in a cast structure, and then tempered under the conditions of 623K × 4 hours.

The composition of the cast iron of Example 1 contained 3.5% by weight of Cr.
%, The carbon content is as low as 0.15% by weight, and the Ni content is 5.6% by weight.
At the stage of the st material, the hardness was Hv450, the metal structure was almost 100% martensite, and no graphite or coarse free carbide was precipitated. The hardness after the tempering treatment at 623K was almost uniform in the depth direction and in the polished surface, and Hv 550 was obtained by the secondary hardening phenomenon due to the tempering. The phase structure of the metal structure did not change even after the tempering treatment. There was almost no thermal deformation due to the tempering treatment, and polishing was performed after tempering to complete a polished platen having a flatness of 10 μm.

Further, as a comparative example with the present invention, a cast iron material having a composition shown in Table 1 was quenched and tempered to produce a polished surface plate having a hardness of Hv450. The polishing platen was also formed with a lattice-like slit and an abrasive supply hole having the same shape as in the above-described example, in an as-cast structure as in the example.

Each of the polishing plates according to Example 1 and Comparative Example 1 was mounted on a lapping device, and lapping of an 8-inch Si wafer was performed. Specifically, an abrasive used for lapping a normal Si wafer (# 12
[0093] Si wafers wrapped in advance with an average particle size of 15 µm) were finely polished with fine # 3000 (average particle size 5 µm) alumina-zirconia-based abrasive grains using the respective polishing plates according to Example 1 and Comparative Example 1. Wrapped again. According to this re-wrapping, if the wrapping time is the same time,
Wafer flatness accuracy is improved to 1/3.

The flatness accuracy and the amount of scratches of the Si wafer showed the same value, and it was confirmed that the polishing platen according to Example 1 was comparable to the conventional polishing platen (Comparative Example 1).
However, in the polishing platen of Comparative Example 1 which had been subjected to quenching and tempering, the depth of the lattice-shaped slits near the outer periphery became shallower by the amount of heat deformation during quenching, and was about 7 mm. On the other hand, in the polishing table of Example 1, the depth of 15 mm at the time of processing was maintained as it was, and finally, the life of the polishing table (the number of relapping polishing) was about 2.35 million, and about 720,000 of the comparative example. It is about three times higher than the number of sheets.

Example 2 Using a cast iron having the composition shown in Table 1, a polishing plate having the same shape as in Example 1 was produced. The polishing platen according to the second embodiment includes: a
At the stage of the s cast material, the hardness was Hv 400, the area ratio occupied by the martensite structure in the metal structure was 60%, and graphite and coarse free carbide were not precipitated.

The polished platen was mounted on the same lapping apparatus as in Example 1 without tempering or the like as cast material, and wrapped an 8-inch Si wafer again (lapping abrasive grains: # 3000). Was carried out. The accuracy of the flatness of the Si wafer and the generation of scratches are the same as those in Example 1, and the life of the polishing platen (the number of polished wafers) is about 1.81 million, which is equivalent to that of Example 1. I confirmed that.

[0045]

[Table 1] In addition, when each of the lapping plates of Examples 1 and 2 was applied to lapping of a 2-inch GaAs semiconductor substrate, good results were obtained.

Example 3 A cast iron having the composition shown in Table 2 was cast, and the casting had an outer diameter of 1400 m.
The polishing platen 1 shown in FIG. 1 having a m of 400 mm in inner diameter and a thickness of 60 mm was produced. The processing of a grid-like slit 2 with a width of 2 mm, a depth of 15 mm and a forming pitch of 40 mm and an abrasive supply hole 3 with a diameter of 8 mm is as
It was processed in a cast structure, and then tempered under the conditions of 673K × 4 hours.

The cast iron composition of Example 3 has a C content of 0.1% by weight within the solid solution range and also contains 8.5% by weight of Ni.
20, the area ratio of martensite structure in the metal structure is 95%
And no graphite and coarse free carbide were precipitated. The hardness after the tempering treatment was substantially uniform in the depth direction and in the polished surface, and Hv 500 was obtained. In addition, the area ratio of the martensite structure after tempering is 100%
Met. There was almost no thermal deformation due to the tempering treatment, and polishing was performed after tempering to complete a polished platen having a flatness of 10 μm.

The polishing platen according to the third embodiment described above was mounted on a lapping apparatus, and a Si wafer previously lapped with an abrasive of # 1200 (average particle size: 15 μm) was mounted in the same manner as in the first embodiment.
Relapping was performed using fine # 3000 (average particle size 5 μm) alumina-zirconia abrasive grains. The flatness accuracy and the amount of scratch generation of the Si wafer are the same as those of Comparative Example 1 described above. Finally, the life of the polishing platen (the number of wafers polished) is about 2.1 million, which is smaller than that of Comparative Example 1 described above. It has improved about three times.

Example 4 A polished platen having the same shape as in Example 3 was produced using cast iron having the composition shown in Table 2. The polishing platen according to the fourth embodiment has a
At the stage of the s cast material, the hardness was Hv 498, the area ratio occupied by the martensite structure in the metal structure was 95%, and graphite and coarse free carbide were not precipitated.

This lapping plate was mounted on a lapping apparatus similar to that of Example 3 without tempering or the like as cast material, and re-lapping of an 8-inch Si wafer (lapping abrasive: # 3000) Was carried out. The accuracy of the flatness of the Si wafer and the generation of scratches are the same as those of the third embodiment, and the life of the polishing platen (the number of polished wafers) is about 2.08 million, which is the same as that of the third embodiment. I confirmed that.

[0051]

[Table 2] In addition, when each of the polishing surface plates of Example 3 and Example 4 described above was applied to lapping of a 2-inch GaAs semiconductor substrate, good results were obtained.

[0052]

As described above, according to the polishing tool material of the present invention, Hv 250
The high hardness described above can be achieved, and there are almost no coarse hard precipitates, and excellent texture and uniformity of hardness can be obtained. Therefore, according to the polishing platen of the present invention made of such a material for a polishing tool, it is possible to perform the polishing work of various workpieces with high accuracy, and to prolong the life and reduce the cost of the polishing platen. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the total carbon content and the solid solution carbon content in an iron-based material.

FIG. 2 is a Schaeffler structure diagram showing a phase structure according to Ni equivalent and Cr equivalent of an iron-based material.

FIG. 3 is a diagram showing a configuration of a polishing platen according to an embodiment of the present invention.

[Explanation of symbols]

 1 ... Polishing surface plate

Claims (3)

[Claims] (1) C, 1% or more of not less than 0.2% by weight and less than 0.8% by weight.
Weight% or more and 7 weight% or less, 4 weight% or more and 7 weight%
It is composed of an iron-based material containing the following Ni, 1% by weight or less of Mn, and 1% by weight or less of Cr, and has a hardness of
A material for polishing tools characterized by having an Hv of 250 or more. 2. Less than 0.2% by weight of C, 1.5% by weight or more
3.5% by weight or less of Si, 7% by weight or more and 17% by weight or less of N
i. An abrasive tool material comprising an iron-based material containing 1% by weight or less of Mn and 4% by weight or less of Cr, wherein the iron-based material has a hardness of Hv 250 or more. 3. A polishing platen comprising the polishing tool material according to claim 1 or 2.