JP2014012328A - Vitrified bond super abrasive gran wheel, and method for manufacturing wafer using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vitrified bond super abrasive grain wheel capable of stably exhibiting grinding performance.SOLUTION: There is provided a vitrified bond super abrasive grain wheel 1 having a super abrasive grain layer 13 formed by bonding super abrasive grains 10 with vitrified bonds 20 and 30, wherein the super abrasive grain layer 13 comprises: a first super abrasive grain layer 11 formed by bonding the super abrasive grains 10 with the vitrified bond 20; and a second super abrasive grain layer 12 composed of aggregate super abrasive grains in which the super abrasive grains 10 become clusters with the vitrified bond 30.

Description

  The present invention relates to a vitrified bonded superabrasive wheel having a porous structure in which superabrasive grains are bonded by vitrified bond.

Vitrified bond wheels are known in which superabrasive grains (diamond abrasive grains, CBN abrasive grains), general abrasive grains (SiC abrasive grains, AL ₂ O ₃ abrasive grains) and the like are used as abrasive grains and these are bonded by vitrified bonds.

JP 54-39292 A JP 59-161269 A Japanese Patent Laid-Open No. 3-184771

  However, when grinding is performed with a conventional vitrified bond superabrasive wheel, there is a problem in that the grinding resistance value increases as the grinding process continues and the grinding resistance value is not stable.

  In addition, in the vitrified bond superabrasive wheel using ultrafine superabrasive grains having an average grain size of 1 μm or less, there is a problem that the wear rate of the superabrasive layer is high and the grinding performance is not stable. .

  In order to solve the above problems, the present invention provides a vitrified bond superabrasive wheel having a superabrasive layer in which superabrasive grains are bonded by vitrified bond, wherein the superabrasive layer vitrifies the superabrasive grains. A vitrified bond superabrasive wheel comprising a first superabrasive layer bonded by a bond and a second superabrasive layer made of aggregated superabrasive grains in which the superabrasives are clustered by vitrified bonds.

  In the vitrified bond superabrasive wheel configured as described above, stable grinding performance can be exhibited by the action of the first and second superabrasive layers.

  Judgment of whether or not it is a cluster is considered to be a cluster when 10 or more superabrasive grains surrounded by vitrified bonds are continuously joined in the superabrasive layer. However, the superabrasive grains present in the outer peripheral portion of the cluster are not necessarily surrounded by vitrified bonds.

Preferably, the bonding degree of the first superabrasive grain layer is lower than that of the second superabrasive grain layer.
The bond degree indicates the ratio between superabrasive grains and vitrified bonds, and the measurement is substituted by the area ratio between superabrasive grains and bonds in the cross-sectional structure. Specifically, electronic data of the image is obtained from SEM (scanning electron microscope) observation of the tissue cross section, and the superabrasive grain part, bond part and pore part are classified by image analysis software, and the respective area ratios are obtained. Can be calculated.

  Preferably, in the first superabrasive grain layer, the superabrasive grains are bonded together by a bond bridge having a thickness smaller than the superabrasive grain diameter.

  Regarding the bond bridge dimensions, the length of the bond bridge is the length at which the perpendicular to the connection line extends in the vitrified bond at the midpoint of the connection line by connecting the nearest distances between adjacent abrasive grains. It is said.

  Preferably, in the second superabrasive grain layer, the superabrasive grains are bonded together by a bond bridge having a thickness larger than the superabrasive grain diameter.

Preferably, the second superabrasive layer surrounds the pores.
Preferably, the ratio of the total of superabrasive grains and vitrified bonds in the first superabrasive grain layer to the volume of the entire superabrasive grain layer is 10 to 50% by volume, of the second superabrasive grain layer. The ratio of the total of superabrasive grains and vitrified bonds is 5 to 30% by volume.

  Regarding these volumes, in the cross-sectional structure, the area ratio of superabrasive grains, vitrified bonds, and pores is obtained by image analysis, and the area ratio is defined as the volume ratio.

Preferably, the softening temperature of the vitrified bond is 600 to 900 ° C.
Preferably, it is used for grinding a wafer containing at least one of silicon, sapphire, and a compound semiconductor.

  Preferably, in the method for manufacturing a wafer, a wafer including at least one of silicon, sapphire, and a compound semiconductor is ground using any one of the above-described vitrified bond superabrasive wheels.

It is sectional drawing which expands and shows a part of superabrasive layer of the vitrified bond superabrasive wheel according to embodiment of this invention. It is sectional drawing of a 1st superabrasive grain layer. It is sectional drawing of a 2nd superabrasive grain layer. It is sectional drawing shown in order to demonstrate a bond bridge. It is a schematic diagram which shows the system which grinds a wafer with a surface grinder.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is an enlarged sectional view showing a part of a superabrasive layer of a vitrified bonded superabrasive wheel according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the first superabrasive grain layer. FIG. 3 is a cross-sectional view of the second superabrasive layer. FIG. 4 is a cross-sectional view for explaining the bond bridge.

  1 to 4, a vitrified bond superabrasive wheel 1 has a superabrasive layer 13 in which superabrasive grains 10 are bonded by vitrified bonds 20 and 30. A first superabrasive grain layer 11 in which 10 is bonded by vitrified bonds 20 and a second superabrasive grain layer 12 composed of aggregate superabrasive grains in which the superabrasive grains 10 are clustered by vitrified bonds are dispersedly arranged. .

  The first superabrasive grain layer 11 and the second superabrasive grain layer 12 made of aggregate superabrasive grains in which the superabrasive grains 10 are clustered by vitrified bonds 20 are arranged in a dispersed manner, whereby vitrified bond superabrasives. The grinding characteristics of the grain wheel 1 can be changed over a wide range. Accordingly, it is possible to select a wheel specification that best suits the type of workpiece, grinding conditions, and type of grinding device.

  As the vitrified bonds 20 and 30, vitrified bonds having a known composition can be applied. For example, it is possible to apply a vitrified bond having the following composition.

SiO ₂ : 30 to 50% by mass, Al ₂ O ₃ : 2 to 10% by mass, B ₂ O ₃ : 40 to 60% by mass, RO (RO is one or more kinds of oxidation selected from CaO, MgO, and BaO) Product): 1 to 10% by mass, R ₂ O (R ₂ O is one or more oxides selected from Li ₂ O, Na ₂ O and K ₂ O): 2 to 5% by mass.

  Needless to say, a vitrified bond other than the above can be applied to the present invention.

  In the vitrified bond superabrasive wheel 1, the bonding degree of the first superabrasive grain layer 11 is preferably lower than that of the second superabrasive grain layer 12.

  Since the bonding degree of the first superabrasive grain layer 11 is lower than the bonding degree of the second superabrasive grain layer 12, the first superabrasive grain layer 11 is worn and retracted at a preferred speed during the grinding process. Can do. Therefore, since only the second superabrasive grain layer 12 protrudes and contributes to the grinding process, a stable and good sharpness can be maintained for a long period of time.

  In particular, when a workpiece is surface ground by a rotary table type vertical surface grinding machine using a cup-shaped wheel (for example, type 6A2 defined in JIS B4131, etc.), the first and second super It is possible to select a wheel specification that can maintain a good sharpness over a long period of time even when the contact area between the abrasive grain layers 11 and 12 and the workpiece increases.

  In the vitrified bond superabrasive wheel 1, preferably, in the first superabrasive grain layer 11, the superabrasive grains 10 are bonded by a bond bridge having a thickness smaller than the grain diameter of the superabrasive grains 10.

  As shown in FIG. 4, with respect to the dimensions of the bond bridge, the connection line 18 is formed by connecting the closest distances between the adjacent superabrasive grains 10, and a perpendicular to the connection line 18 is formed at an intermediate point of the connection line 18. The length L extending in the vitrified bond 20 is the bond bridge dimension.

  In order to make the first superabrasive layer 11 have a lower degree of bonding than the second superabrasive layer 12, the first superabrasive layer 11 is composed of superabrasive grains 10 each other. Bonded by a bond bridge having a thickness smaller than the diameter.

  In the vitrified bond superabrasive wheel 1, the second superabrasive layer 12 is bonded to each other by a bond bridge whose superabrasive grains 10 are larger in diameter than the superabrasive grains 10.

  The second superabrasive grain layer 12 is bonded to each other by a bond bridge having a thickness larger than the grain diameter of the superabrasive grains 10 in order to increase the degree of bonding than the first superabrasive grain layer 11. . In order to further increase the degree of bonding, the gap is filled with vitrified bonds so that pores (holes) are not formed in the gap between the superabrasive grains 10.

  In the vitrified bond superabrasive wheel 1, the cluster includes pores 50. Here, the cluster means an aggregate superabrasive grain in which a plurality of superabrasive grains 10 are agglomerated or tufted by vitrified bonds 30. Since the cluster constitutes the second superabrasive grain layer 12 that contributes to the grinding process, when the improvement of the sharpness, the improvement of the cooling effect of the coolant, the improvement of the chip discharging property, etc. are necessary, the cluster It is preferable to enclose the pores 50. Judgment of whether or not it is a cluster is that in the superabrasive grain layer 13, when 10 or more superabrasive grains surrounded by the vitrified bond 30 are continuously joined, the mass is regarded as a cluster. The However, the superabrasive grains present in the outer peripheral portion of the cluster are not necessarily surrounded by vitrified bonds.

  In the first superabrasive grain layer 11, a large number of holes 51 exist. The diameter of the circle having the same area as the hole 51 includes a diameter smaller than the average particle diameter of the superabrasive grains 10. In contrast, the pores 50 have a larger diameter than the holes 51. The diameter of a circle having the same area as the pores 50 is larger than the average particle diameter of the superabrasive grains 10.

  Since the first superabrasive grain layer 11 has a large number of holes 51, there is a place where the superabrasive grains are not bonded to each other by a bond bridge. On the other hand, since the void 51 does not exist in the second superabrasive grain layer 12, ten or more superabrasive grains 10 are continuously joined.

  In the vitrified bond superabrasive wheel 1, the ratio of the superabrasive grains and the vitrified bond in the first superabrasive grain layer 11 is preferably 10 to 50 volumes with respect to the entire superabrasive grain layer 13 volume. % Of the second superabrasive layer 12 is 5 to 30% by volume of the total superabrasive grains and vitrified bonds.

  The ratio of the total superabrasive grains and vitrified bonds in the first superabrasive layer 11 is 20 to 40% by volume, and the ratio of the total superabrasive grains and vitrified bonds in the second superabrasive layer 12 is It is more preferable that it is 10-30 volume%, The ratio for which the sum total of a superabrasive grain and a vitrified bond accounts for 30-40 volume% in the 1st superabrasive grain layer 11, and among the 2nd superabrasive grain layer 12 is. The ratio of the total of superabrasive grains and vitrified bonds is most preferably 15 to 25% by volume.

  In the vitrified bond superabrasive wheel 1 of the present invention, preferably, the softening temperature of the vitrified bonds 20 and 30 is 600 to 900 ° C. In particular, when grinding various wafers such as silicon, sapphire, and compound semiconductor, the softening temperature of vitrified bonds 20 and 30 is more preferably 600 to 800 ° C, and most preferably 600 to 700 ° C. . If the softening temperature of the vitrified bonds 20 and 30 is less than 600 ° C., it is not preferable because the holding power of the superabrasive grains decreases, and if it exceeds 900 ° C., the superabrasive grains are damaged by heat.

  The composition of the vitrified bond 20 and the vitrified bond 30 may be the same or different.

  According to said vitrified bond superabrasive wheel 1, the stable good sharpness can be maintained over a long period of time.

Example 1
Details of the vitrified bonded superabrasive wheel of Example 1 are as follows.
The composition of the vitrified bond is as follows.
SiO _2: 40.5 _{wt%, Al} 2 O 3: 6.5 _{wt%, B} 2 O 3: 48.2 wt%
RO (RO is one or more oxides selected from CaO, MgO, and BaO): 1.8% by mass, R ₂ O (R ₂ O is selected from Li ₂ O, Na ₂ O, and K ₂ O) One or more oxides): 3.0% by mass.

  As the superabrasive grains, diamond abrasive grains having an average particle diameter of 1 μm were used, and as the pore forming material, starch, resin, and a bulk or spherical shape having an average particle diameter of 5 μm, 20 μm, and 100 μm were used.

  First, for creating the first superabrasive layer 11, after adding and mixing 20 volume% vitrified bond, 40 volume% diamond abrasive grains, 40 volume% 20 μm pore-forming material, and a known binder, A predetermined granulated powder is obtained by dry pulverization.

  Subsequently, for the production of the second superabrasive layer 12, 30% by volume of vitrified bond, 30% by volume of diamond abrasive grains, 40% by volume of 5 μm pore-forming material, and a known binder are added and mixed, and then dried. A predetermined granulated powder is obtained by pulverization.

  60% by volume of the granulated powder of the first superabrasive layer 11 thus obtained, 30% by volume of the granulated powder of the second superabrasive layer 12 and 10% by volume of the pore forming material of 100 μm were dry mixed. Then, it shape | molded with the press to the chip-shaped molded object, the binder removal process was performed, and it baked at the temperature of 750 degreeC succeedingly.

  The chip after firing is bonded to an aluminum alloy base metal using an adhesive, and then truing and dressing using a conventional grindstone, and the vitrified bond diamond wheel of Example 1 (vitrified bond superabrasive grains). Wheel 1) was completed.

  The wheel has a segment type cup wheel (JIS B4131 6A7S type) having an outer diameter of 200 mm, a superabrasive layer 13 having a width of 4 mm, and a superabrasive layer 13 having a thickness of 5 mm.

  The completed vitrified bond diamond wheel has a first abrasive layer in which a second abrasive layer, which is a cluster composed of bond bridges larger than the abrasive grain size, is bonded with bond bridges smaller than the abrasive grain size. It was confirmed that it was properly dispersed in the abrasive layer.

  The contents described above are results obtained by observing a cut surface of a previously prepared abrasive grain layer with a scanning electron microscope.

  The vitrified bond diamond wheel of Example 1 was attached to a vertical rotary table type surface grinder and the silicon wafer was ground to confirm the effect of the present invention.

  FIG. 5 is a schematic diagram showing a method of grinding a wafer with a surface grinder. Referring to FIG. 5, in grinding method 100, wafer 120 as a work made of silicon was fixed on table 110. The table 110 is rotatable in the direction indicated by the arrow 110R. Vitrified bond superabrasive wheel 1 is rotatable in the direction indicated by arrow 1R. Further, the direction indicated by the arrow 1F is the cutting direction.

  When grinding was performed using the grinding method 100 shown in FIG. 5, the sharpness was good and stable, and the wear amount in the thickness direction of the superabrasive grain layer 13 was also small. When the amount of wear in the thickness direction of the superabrasive grain layer 13 was measured after completion of the grinding, it was 0.5 μm. Further, the load current value of the spindle motor during grinding was 8.8A. Further, the variation in the load current value was 0.1A. The maximum value PV (the difference in height between the highest point and the lowest point in the sample) of the height difference on the surface of the silicon wafer that is the workpiece after processing is 21.2 nm, and the surface roughness Ra is 2.1 nm. Met.

(Example 2)
Details of the vitrified bond superabrasive wheel of Example 2 are as follows.

  The composition of the vitrified bond is the same as in Example 1. The same superabrasive grains and pore forming materials as in Example 1 were used. First, for creating the first superabrasive layer 11, after adding and mixing 20 volume% vitrified bond, 40 volume% diamond abrasive grains, 40 volume% 20 μm pore-forming material, and a known binder, A predetermined granulated powder is obtained by dry pulverization.

  Subsequently, for the production of the second superabrasive layer 12, after adding 30% by volume of vitrified bond, 30% by volume of diamond abrasive grains, 40% by volume of 5 μm pore forming material, and adding a known binder, A predetermined granulated powder is obtained by dry pulverization.

  50% by volume of the granulated powder of the first superabrasive grain layer 11 thus obtained, 40% by volume of the granulated powder of the second superabrasive grain layer 12, and 10% by volume of the 100 μm pore-forming material were dry mixed. Then, it shape | molded with the press to the chip-shaped molded object, the binder removal process was performed, and it baked at the temperature of 750 degreeC succeedingly.

  The chip that has been fired is bonded to an aluminum alloy base metal using an adhesive, and then truing and dressing using a conventional grindstone. Wheel 1) was completed.

  The wheel has a segment type cup wheel (JIS B4131 6A7S type) having an outer diameter of 200 mm, a superabrasive layer 13 having a width of 4 mm, and a superabrasive layer 13 having a thickness of 5 mm.

  The completed vitrified bond diamond wheel has a first abrasive layer in which a second abrasive layer, which is a cluster composed of bond bridges larger than the abrasive grain size, is bonded with bond bridges smaller than the abrasive grain size. It was confirmed that it was properly dispersed in the abrasive layer.

  The contents described above are results obtained by observing a cut surface of a previously prepared abrasive grain layer with a scanning electron microscope.

  The vitrified bond diamond wheel of Example 2 was attached to a vertical rotary table type surface grinder, and the silicon wafer was ground to confirm the effect of the present invention.

  When grinding was performed using the grinding method 100 shown in FIG. 5, the sharpness was good and stable, and the wear amount in the thickness direction of the superabrasive grain layer 13 was also small. When the amount of wear in the thickness direction of the superabrasive grain layer 13 was measured after completion of grinding, it was 0.4 μm. Further, the load current value of the spindle motor during grinding was 8.7 A. Further, the variation of the load current value was 0.2A. The maximum height difference PV (the difference in height between the highest point and the lowest point in the sample) on the surface of the silicon wafer that is the workpiece after processing is 20.7 nm, and the surface roughness Ra is 2.2 nm. Met.

(Example 3)
Details of the vitrified bond superabrasive wheel of Example 3 are as follows.

  The composition of the vitrified bond is the same as in Example 1. The same superabrasive grains and pore forming materials as in Example 1 were used. First, for creating the first superabrasive layer 11, after adding and mixing 20 volume% vitrified bond, 40 volume% diamond abrasive grains, 40 volume% 20 μm pore-forming material, and a known binder, A predetermined granulated powder is obtained by dry pulverization.

  Subsequently, for the production of the second superabrasive layer 12, 40 volume% vitrified bond, 20 volume% diamond abrasive grains, 40 volume% 5 μm pore-forming material, and a known binder are added and mixed, and then dried. A predetermined granulated powder is obtained by pulverization.

  60% by volume of the granulated powder of the first superabrasive layer 11 thus obtained, 30% by volume of the granulated powder of the second superabrasive layer 12 and 10% by volume of the pore forming material of 100 μm were dry mixed. Then, it shape | molded with the press to the chip-shaped molded object, the binder removal process was performed, and it baked at the temperature of 750 degreeC succeedingly.

  The chip that has been fired is bonded to an aluminum alloy base metal using an adhesive, followed by truing dressing using a conventional grindstone, and the vitrified bond diamond wheel of Example 3 (Vitrified bond superabrasive grains). Wheel 1) was completed.

  The wheel has a segment type cup wheel (JIS B4131 6A7S type) having an outer diameter of 200 mm, a superabrasive layer 13 having a width of 4 mm, and a superabrasive layer 13 having a thickness of 5 mm.

  The completed vitrified bond diamond wheel has a first abrasive layer in which a second abrasive layer, which is a cluster composed of bond bridges larger than the abrasive grain size, is bonded with bond bridges smaller than the abrasive grain size. It was confirmed that it was properly dispersed in the abrasive layer.

  The contents described above are results obtained by observing a cut surface of a previously prepared abrasive grain layer with a scanning electron microscope.

  The vitrified bond diamond wheel of Example 3 was attached to a vertical rotary table type surface grinder, and the silicon wafer was ground to confirm the effect of the present invention.

  When grinding was performed using the grinding method 100 shown in FIG. 5, the sharpness was good and stable, and the wear amount in the thickness direction of the superabrasive grain layer 13 was also small. When the amount of wear in the thickness direction of the superabrasive grain layer 13 was measured after completion of the grinding, it was 0.2 μm. Further, the load current value of the spindle motor during grinding was 8.7 A. Further, the variation in the load current value was 0.1A. The maximum value PV (the difference in height between the highest point and the lowest point in the sample) of the height difference on the surface of the processed silicon wafer as the workpiece was 21 nm, and the surface roughness Ra was 2 nm.

Example 4
Details of the vitrified bonded superabrasive wheel of Example 4 are as follows.

  The composition of the vitrified bond is the same as in Example 1. The same superabrasive grains and pore forming materials as in Example 1 were used. First, for the production of the first superabrasive layer 11, after adding 10 volume% vitrified bond, 50 volume% diamond abrasive grains, 40 volume% 20 μm pore forming material, and adding a known binder, A predetermined granulated powder is obtained by dry pulverization.

  Subsequently, for the production of the second superabrasive layer 12, after adding 30% by volume of vitrified bond, 30% by volume of diamond abrasive grains, 40% by volume of 5 μm pore forming material, and adding a known binder, A predetermined granulated powder is obtained by dry pulverization.

  60% by volume of the granulated powder of the first superabrasive layer 11 thus obtained, 30% by volume of the granulated powder of the second superabrasive layer 12 and 10% by volume of the pore forming material of 100 μm were dry mixed. Then, it shape | molded with the press to the chip-shaped molded object, the binder removal process was performed, and it baked at the temperature of 750 degreeC succeedingly.

  The chip that has been fired is bonded to an aluminum alloy base metal using an adhesive, followed by truing dressing using a conventional grindstone, and the vitrified bond diamond wheel of Example 4 (vitrified bond superabrasive grains). Wheel 1) was completed.

  The wheel has a segment type cup wheel (JIS B4131 6A7S type) having an outer diameter of 200 mm, a superabrasive layer 13 having a width of 4 mm, and a superabrasive layer 13 having a thickness of 5 mm.

  The completed vitrified bond diamond wheel has a first abrasive layer in which a second abrasive layer, which is a cluster composed of bond bridges larger than the abrasive grain size, is bonded with bond bridges smaller than the abrasive grain size. It was confirmed that it was properly dispersed in the abrasive layer.

  The contents described above are results obtained by observing a cut surface of a previously prepared abrasive grain layer with a scanning electron microscope.

  The vitrified bond diamond wheel of Example 4 was attached to a vertical rotary table type surface grinder, and the silicon wafer was ground to confirm the effect of the present invention.

  When grinding was performed using the grinding method 100 shown in FIG. 5, the sharpness was good and stable, and the wear amount in the thickness direction of the superabrasive grain layer 13 was also small. When the amount of wear in the thickness direction of the superabrasive layer 13 was measured after completion of the grinding, it was 0.7 μm. Moreover, the load current value of the spindle motor during grinding was 8.5A. Further, the variation of the load current value was 0.2A. The maximum height difference PV (the difference in height between the highest point and the lowest point in the sample) on the surface after processing of the silicon wafer as the workpiece is 22.3 nm, and the surface roughness Ra is 2.3 nm. Met.

(Comparative Example 1)
On the other hand, in the vitrified bond diamond wheel of Comparative Example 1, 90% by volume of the granulated powder of the second superabrasive grain layer 12 of Example 1 and 10% by volume of a pore forming material of 100 μm were mixed.

  And when the grinding process similar to Example 1 was performed, although the sharpness was good, the abrasion amount of the thickness direction of the superabrasive grain layer 13 was also small. When the amount of wear in the thickness direction of the superabrasive grain layer 13 was measured after completion of the grinding process, it was 0.1 μm, and the load current value of the spindle motor during the grinding process was 7.8 A. Further, the variation of the load current value was 0.8A. The maximum height difference PV (the difference in height between the highest point and the lowest point in the sample) on the surface of the silicon wafer that is the workpiece after processing is 39.1 nm, and the surface roughness Ra is 4.1 nm. Met.

(Comparative Example 2)
Furthermore, in the vitrified bond diamond wheel of Comparative Example 2, 90% by volume of the granulated powder of the first superabrasive grain layer 11 of Example 1 and 10% by volume of the pore forming material of 100 μm were mixed.

  And when the same grinding process as Example 1 was performed, although the abrasion of the thickness direction of the superabrasive grain layer 13 was large, the sharpness was unstable. When the amount of wear in the thickness direction of the superabrasive grain layer 13 was measured after completion of the grinding process, the load current value of the spindle motor during the grinding process was 3 μm, which was 8.4 A. Further, the variation of the load current value was 0.5A. The maximum height difference PV (the difference in height between the highest point and the lowest point in the sample) on the surface of the silicon wafer that is the workpiece after processing is 20.6 nm, and the surface roughness Ra is 2.2 nm. Met.

(Comparative Example 3)
Details of the vitrified bonded superabrasive wheel of Comparative Example 3 are as follows.

  The composition of the vitrified bond is the same as in Example 1. The same superabrasive grains and pore forming materials as in Example 1 were used. First, for creating the first superabrasive layer 11, after adding and mixing 20 volume% vitrified bond, 40 volume% diamond abrasive grains, 40 volume% 20 μm pore-forming material, and a known binder, A predetermined granulated powder is obtained by dry pulverization.

  Subsequently, for the production of the second superabrasive layer 12, 50% by volume of vitrified bond, 50% by volume of diamond abrasive grains, and a known binder are added and mixed, and then a predetermined granulated powder is obtained by dry grinding. obtain. No pore forming material is used.

  60% by volume of the granulated powder of the first superabrasive layer 11 thus obtained, 30% by volume of the granulated powder of the second superabrasive layer 12 and 10% by volume of the pore forming material of 100 μm were dry mixed. Then, it shape | molded with the press to the chip-shaped molded object, the binder removal process was performed, and it baked at the temperature of 750 degreeC succeedingly.

  The chip that has been fired is bonded to an aluminum alloy base metal using an adhesive, and then truing and dressing using a conventional grindstone, and the vitrified bond diamond wheel of Comparative Example 3 (Vitrified bond superabrasive grains). Wheel 1) was completed.

  The wheel has a segment type cup wheel (JIS B4131 6A7S type) having an outer diameter of 200 mm, a superabrasive layer 13 having a width of 4 mm, and a superabrasive layer 13 having a thickness of 5 mm.

  The finished vitrified bond diamond wheel has a second abrasive layer, which is a cluster composed of bond bridges larger than the abrasive grain size, in the first abrasive layer bonded by bond bridges smaller than the abrasive grain size. It was confirmed that they existed dispersed. The second superabrasive layer was not provided with pores having an average particle size of about 5 μm due to the pore-forming material.

  The contents described above are results obtained by observing a cut surface of a previously prepared abrasive grain layer with a scanning electron microscope.

  The vitrified bond diamond wheel of Comparative Example 3 was attached to a vertical rotary table type surface grinder and the silicon wafer was ground to confirm the effect of the present invention.

  When grinding was performed using the grinding method 100 shown in FIG. 5, the sharpness was unstable. The wear amount in the thickness direction of the superabrasive layer 13 was small. When the amount of wear in the thickness direction of the superabrasive grain layer 13 was measured after completion of grinding, it was 0.4 μm. The load current value of the spindle motor during grinding was 9A. Further, the variation of the load current value was 0.4A. The maximum value PV (the difference in height between the highest point and the lowest point in the sample) of the height difference on the surface of the silicon wafer as the workpiece after processing is 29.8 nm, and the surface roughness Ra is 3.1 nm. Met.

(Comparative Example 4)
Details of the vitrified bonded superabrasive wheel of Comparative Example 4 are as follows.

  The composition of the vitrified bond is the same as in Example 1. The same superabrasive grains and pore forming materials as in Example 1 were used. First, in order to create the first superabrasive layer 11, 33% by volume of vitrified bond, 67% by volume of diamond abrasive grains, and a known binder are added and mixed, and then a predetermined granulated powder is obtained by dry grinding. obtain. No pore forming material is used.

  Subsequently, for the production of the second superabrasive layer 12, after adding 30% by volume of vitrified bond, 30% by volume of diamond abrasive grains, 40% by volume of 5 μm pore forming material, and adding a known binder, A predetermined granulated powder is obtained by dry pulverization.

  60% by volume of the granulated powder of the first superabrasive layer 11 thus obtained, 30% by volume of the granulated powder of the second superabrasive layer 12 and 10% by volume of the pore forming material of 100 μm were dry mixed. Then, it shape | molded with the press to the chip-shaped molded object, the binder removal process was performed, and it baked at the temperature of 750 degreeC succeedingly.

  The chip that has been fired is bonded to an aluminum alloy base metal using an adhesive, and then subjected to truing dressing using a conventional grindstone, and the vitrified bond diamond wheel of Comparative Example 4 (vitrified bond superabrasive grains). Wheel 1) was completed.

  The wheel has a segment type cup wheel (JIS B4131 6A7S type) having an outer diameter of 200 mm, a superabrasive layer 13 having a width of 4 mm, and a superabrasive layer 13 having a thickness of 5 mm.

  The completed vitrified bond diamond wheel has a first abrasive layer in which a second abrasive layer, which is a cluster composed of bond bridges larger than the abrasive grain size, is bonded with bond bridges smaller than the abrasive grain size. It was confirmed that it was properly dispersed in the abrasive layer. The first superabrasive layer was not provided with pores having an average particle size of about 20 μm due to the pore-forming material.

  The contents described above are results obtained by observing a cut surface of a previously prepared abrasive grain layer with a scanning electron microscope.

  The vitrified bond diamond wheel of Comparative Example 4 was attached to a vertical rotary table type surface grinder, and the silicon wafer was ground to confirm the effect of the present invention.

  When grinding was performed using the grinding method 100 shown in FIG. 5, the sharpness was unstable. The wear amount in the thickness direction of the superabrasive layer 13 was small. When the amount of wear in the thickness direction of the superabrasive grain layer 13 was measured after completion of the grinding, it was 0.3 μm. Further, the load current value of the spindle motor during grinding was 9.2A. Further, the variation of the load current value was 0.5A. The maximum height difference PV (the difference in height between the highest point and the lowest point in the sample) on the surface of the silicon wafer that is the workpiece after processing is 25.2 nm, and the surface roughness Ra is 2.8 nm. Met.

(Comparative Example 5)
Details of the vitrified bond superabrasive wheel of Comparative Example 5 are as follows.

  The composition of the vitrified bond is the same as in Example 1. The same superabrasive grains and pore forming materials as in Example 1 were used. First, for creating the first superabrasive layer 11, after adding and mixing 20 volume% vitrified bond, 40 volume% diamond abrasive grains, 40 volume% 20 μm pore-forming material, and a known binder, A predetermined granulated powder is obtained by dry pulverization.

  Subsequently, for the production of the second superabrasive layer 12, after adding 30% by volume of vitrified bond, 30% by volume of diamond abrasive grains, 40% by volume of 5 μm pore forming material, and adding a known binder, A predetermined granulated powder is obtained by dry pulverization.

  Thus obtained 65% by volume of the granulated powder of the first superabrasive layer 11 and 35% by volume of the granulated powder of the second superabrasive layer 12 were dry mixed. No pore forming material is used. Then, it shape | molded with the press to the chip-shaped molded object, the binder removal process was performed, and it baked at the temperature of 750 degreeC succeedingly.

  The chip that has been fired is bonded to an aluminum alloy base metal using an adhesive, followed by truing dressing using a conventional grindstone, and the vitrified bond diamond wheel of Example 3 (Vitrified bond superabrasive grains). Wheel 1) was completed.

  The wheel has a segment type cup wheel (JIS B4131 6A7S type) having an outer diameter of 200 mm, a superabrasive layer 13 having a width of 4 mm, and a superabrasive layer 13 having a thickness of 5 mm.

  The completed vitrified bond diamond wheel has a first abrasive layer in which a second abrasive layer, which is a cluster composed of bond bridges larger than the abrasive grain size, is bonded with bond bridges smaller than the abrasive grain size. It was confirmed that it was properly dispersed in the abrasive layer. Large pores having an average particle size of about 100 μm due to the pore-forming material were not provided.

  The contents described above are results obtained by observing a cut surface of a previously prepared abrasive grain layer with a scanning electron microscope.

  The vitrified bond diamond wheel of Example 3 was attached to a vertical rotary table type surface grinder, and the silicon wafer was ground to confirm the effect of the present invention.

  When grinding was performed using the grinding method 100 shown in FIG. 5, the sharpness became unstable at an early stage, and it was necessary to stop the machining.

  The results of Examples and Comparative Examples are shown in Table 1.

  In the judgment column of Table 1, “◯” indicates a good result, and “×” indicates a bad result. Further, “pores (20 μm)” indicates the ratio of pore-forming materials having an average particle diameter of 20 μm, and “pores (5 μm)” indicates the ratio of pore-forming materials having an average particle diameter of 5 μm. ")" Indicates the proportion of pore-forming material having an average particle size of 100 μm.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Vitrified bond superabrasive wheel, 10 superabrasive grain, 11 1st superabrasive grain layer, 12 2nd superabrasive grain layer, 20, 30 Vitrified bond, 50 porosity, 51 void | hole.

Claims (9)

A vitrified bond superabrasive wheel having a superabrasive layer in which superabrasive grains are bonded by vitrified bond,
The superabrasive layer includes a first superabrasive layer in which the superabrasive grains are bonded by vitrified bonds, and a second superabrasive layer in which the superabrasive grains are clustered by vitrified bonds. A vitrified bond superabrasive wheel comprising an abrasive layer.   2. The vitrified bonded superabrasive wheel according to claim 1, wherein the degree of bonding of the first superabrasive layer is lower than that of the second superabrasive layer.   The vitrified bond superabrasive wheel according to claim 1 or 2, wherein in the first superabrasive layer, the superabrasive grains are bonded together by a bond bridge having a thickness smaller than that of the superabrasive grain. .   The vitrified bond according to any one of claims 1 to 3, wherein in the second superabrasive grain layer, the superabrasive grains are bonded to each other by a bond bridge having a thickness larger than the grain size of the superabrasive grains. Super abrasive wheel.   The vitrified bond superabrasive wheel according to any one of claims 1 to 4, wherein the second superabrasive layer surrounds pores.   The ratio of the total of the superabrasive grains and the vitrified bond in the first superabrasive grain layer to the total volume of the superabrasive grain layer is 10 to 50% by volume, and the second superabrasive grain layer. The vitrified bond superabrasive wheel according to any one of claims 1 to 5, wherein a ratio of the total of the superabrasive grains and the vitrified bond is 5 to 30% by volume.   The vitrified bond superabrasive wheel according to any one of claims 1 to 6, wherein a softening temperature of the vitrified bond is 600 to 900 ° C.   The vitrified bonded superabrasive wheel according to any one of claims 1 to 7, which is used for grinding a wafer containing at least one of silicon, sapphire, and a compound semiconductor.   A method for manufacturing a wafer, comprising: grinding a wafer containing at least one of silicon, sapphire, and a compound semiconductor using the vitrified bond superabrasive wheel according to claim 1.

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