JP2004025372A - Grinding wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a load on a spindle driving a grinding wheel, in grinding using the grinding wheel composed of grinding stone pieces fixed on an end face of a wheel base. <P>SOLUTION: This grinding wheel is provided: with the wheel base 11; the grinding stone pieces 13 fixed on the end face of the wheel base 11; and a flexible member 12 fixed on a position adjacent to the grinding stone pieces 13 on the end face of the wheel base 11. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polishing wheel used for polishing a plate-like object such as a semiconductor wafer.
[0002]
[Prior art]
When polishing the surface of a plate-like object such as a semiconductor wafer, for example, a polishing grindstone 60 as shown in FIG. 23 is used.
[0003]
In this polishing whetstone 60, a plurality of whetstone pieces 62 formed by solidifying abrasive grains such as diamond with an appropriate bonding agent such as resin bond, vitrified bond, metal bond, etc. were fixed to the end surface of a ring-shaped wheel base 61. It has a configuration.
[0004]
The polishing grindstone 60 thus configured is fixed to a mounter 64 formed at the tip of a spindle 63 as shown in FIG. Then, the polishing means 65 is lowered while rotating the spindle 63 at a high speed of about 3000 rpm to 6000 rpm, and the polishing grindstone 62 rotating at a high speed is brought into contact with the surface of a plate-like object 67 held on a chuck table 66 to thereby obtain a plurality of grindstones. The surface of the plate 67 is polished by the piece 62. In addition, at the time of polishing, a polishing liquid (not shown) flowing through the inside of the spindle 63 and flowing out of the wheel base 61 is supplied to a contact portion between the grindstone piece 62 and the plate-shaped object 67, so that the spindle The load resistance applied to 63 is reduced.
[0005]
[Problems to be solved by the invention]
However, even if a sufficient polishing liquid is supplied to the contact portion, the pressure applied to the grindstone piece 62 during polishing is still relatively high, and an excessive load may be applied to the spindle 63, which shortens the life of the polishing means 65. There's a problem.
[0006]
Therefore, in polishing using a rotating polishing wheel, there is a problem in reducing the load on the spindle.
[0007]
[Means for Solving the Problems]
As a specific means for solving the above problems, the present invention is a polishing whetstone provided with a wheel base and a grindstone piece fixed to an end face of the wheel base, and a whetstone is provided on an end face of the wheel base. A polishing grindstone characterized in that a flexible member is fixed to a position adjacent to a piece.
[0008]
The polishing whetstone is arranged so that the exposed surface of the flexible member is flush with the exposed surface of the whetstone piece, or is protruded from the exposed surface of the whetstone piece. It is an additional requirement that the flexible member is formed of felt and that the wheel base is provided with a polishing liquid outflow hole for discharging the polishing liquid.
[0009]
In the polishing whetstone configured as described above, the flexible member is fixed at a position adjacent to the whetstone piece, so that the contact area at the time of polishing is widened, the pressure applied to the whetstone piece is reduced, and the surface burn is prevented from occurring. And the load on the spindle is reduced.
[0010]
Further, if abrasive grains are mixed into the flexible member, polishing can be performed more efficiently.
[0011]
Furthermore, when a polishing liquid outflow hole is provided in the wheel base, the polishing liquid flowing out from the polishing liquid outflow hole is uniformly guided by the flexible member to the contact portion between the grindstone piece and the plate-shaped object, so Such pressure is reduced, and the load on the spindle is further reduced.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Some embodiments of the present invention will be described with reference to the drawings. First, the grinding wheel 10 shown in FIGS. 1 to 3 will be described. As shown in FIG. 1, the polishing grindstone 10 has a configuration in which a flexible member 12 is fixed to an end surface of a ring-shaped wheel base 11. As the flexible member 12, for example, felt, urethane, or the like can be used.
[0013]
As shown in FIG. 2, a large number of cylindrical grindstone pieces 13 are fixed to the wheel base 11 in an annular shape, and a flexible member 12 is fixed so as to surround each of the grindstone pieces 13. The exposed surface of the flexible member 12 is flush with the exposed surface of the grindstone piece 13 as shown in FIG. 3 or slightly (1 mm to 0 mm) as compared with the exposed surface of the grindstone piece 13 as shown in FIG. .5 mm) in a protruding state, and in any case, the grindstone pieces 13 are embedded in the flexible member 12. The flexible member 12 does not necessarily need to cover the entire end surface of the wheel base 11 as in the example shown in the drawing, and may be provided at a position adjacent to the grindstone piece 13.
[0014]
The grindstone pieces 13 are formed by solidifying abrasive grains such as diamond with a bonding agent such as a resin bond, a vitrified bond, or a metal bond.
[0015]
The flexible member 12 can contain abrasive grains in a dispersed state, and the abrasive grains include silica, alumina, zirconia, manganese dioxide, ceria, colloidal silica, fumed silica, boehmite, bayerite, and the like. Diamond or the like can be used.
[0016]
FIG. 5 shows an example of an arrangement state of the flexible member 12 and the grindstone pieces 13 on the bottom surface of the polishing grindstone 10. The number of the grindstone pieces 13 is different from FIG. It is configured to be annularly fixed at a fixed interval between the inner peripheral portion and the outer peripheral portion of the member 12 and to be embedded in the flexible member 12.
[0017]
The polishing grindstone 14 shown in FIG. 6 has a configuration in which a flexible member 12 is fixed to an end surface of a ring-shaped wheel base 11 as in FIG. 1. In this example, a cylindrical grindstone piece 13 is formed of a flexible member. The inner peripheral portion and the outer peripheral portion of the flexible member 12 are fixed in an annular shape without any gap, and are embedded in the flexible member 12.
[0018]
The polishing grindstone 15 shown in FIG. 7 has a configuration in which a flexible member 12 is fixed to an end surface of a ring-shaped wheel base 11 as in FIG. 1. The outer peripheral portion of the member 12 is annularly fixed at regular intervals and is embedded in the flexible member 12.
[0019]
A polishing grindstone 16 shown in FIG. 8 has a configuration in which a flexible member 12 is fixed to an end surface of a ring-shaped wheel base 11 as in FIG. 1. In this example, a column-shaped grindstone piece 13 is The outer periphery of the member 12 is fixed in an annular shape without any gap, and is configured to be embedded in the flexible member 12.
[0020]
A polishing grindstone 17 shown in FIG. 9 has a configuration in which a flexible member 12 is fixed to an end surface of a ring-shaped wheel base 11 as in FIG. Is fixed in a circular shape at a fixed interval between the outer peripheral portion and the outer peripheral portion, as in the example shown in FIG. 3, but the point that each grinding wheel piece 13a is formed in a rectangular parallelepiped shape is described above. It is different from the example. Each of the grindstone pieces 13a is fixed so as to be embedded in the flexible member 12.
[0021]
A polishing grindstone 18 shown in FIG. 10 has a configuration in which a flexible member 12 is fixed to an end surface of a ring-shaped wheel base 11 similarly to FIG. 1, and a grinding stone piece 13a formed in a rectangular parallelepiped shape has a flexible member 12 Are fixed in an annular shape at a constant interval on the outer peripheral portion of the flexible member 12 and are embedded in the flexible member 12.
[0022]
A polishing grindstone 19 shown in FIG. 11 has a configuration in which a flexible member 12 is fixed to an end surface of a ring-shaped wheel base 11 similarly to FIG. 1, and a grinding stone piece 13 a formed in a rectangular parallelepiped shape has a flexible member 12. Are fixed in a double annular shape at a fixed interval between the inner peripheral portion and the outer peripheral portion, and are embedded in the flexible member 12.
[0023]
A polishing wheel 20 shown in FIG. 12 has a configuration in which a flexible member 12 is fixed to an end surface of a ring-shaped wheel base 11 similarly to FIG. 1, and a grinding stone piece 13a formed in a rectangular parallelepiped shape has a flexible member 12a. Are fixed in a double annular shape at a fixed interval between the inner peripheral portion and the outer peripheral portion and at the outer peripheral portion, and are configured to be embedded in the flexible member 12.
[0024]
A polishing wheel 21 shown in FIG. 13 has a configuration in which a flexible member 12 is fixed to an end surface of a ring-shaped wheel base 11 similarly to FIG. 1, and a grinding wheel piece 13a formed in a rectangular parallelepiped shape has a flexible member 12a. Are fixed in a double annular shape at a fixed interval between the inner peripheral portion and the outer peripheral portion and at the inner peripheral portion, and are configured to be embedded in the flexible member 12.
[0025]
A polishing wheel 22 shown in FIG. 14 has a configuration in which a flexible member 12 is fixed to an end surface of a ring-shaped wheel base 11 as in FIG. The inner peripheral portion and the outer peripheral portion are fixed in a triple annular shape at predetermined intervals in the inner peripheral portion and the outer peripheral portion, and are embedded in the flexible member 12. In the examples of FIGS. 9 to 14, the example in which the grinding stone pieces 13 a are fixed at intervals is described. However, the grinding stone pieces 13 a may be fixed to each other so as to be in close contact with each other without an interval.
[0026]
The grinding wheels shown in FIGS. 15 to 19 are different from the grinding wheels shown in the examples up to FIG. 12 in that the central portion of the flexible member 23 does not penetrate and is formed in a normal circular shape. In this case, the wheel base may be formed in a ring shape as shown in FIG. 1, or may be formed in a normal circular shape corresponding to the shape of the flexible member 23.
[0027]
A polishing grindstone 25 shown in FIG. 15 is configured such that a cylindrical grindstone piece 13 is fixed to a wheel base without a gap at an outer peripheral portion of a circular flexible member 23, and these are embedded in the flexible member 23. The grinding stone pieces 13 may be fixed at intervals.
[0028]
The polishing grindstone 26 shown in FIG. 16 has a configuration in which rectangular parallelepiped grindstone pieces 13 a are fixed to the wheel base at regular intervals on the outer peripheral portion of the circular flexible member 23, and these are embedded in the flexible member 23. Have been. Note that the grinding wheel pieces 13a can be fixed so that adjacent grinding wheel pieces are in close contact with each other without an interval.
[0029]
In the polishing grindstone 27 shown in FIG. 17, cylindrical grindstone pieces 13 are fixed to a wheel base at regular intervals so as to form a triangle on a circular flexible member 25, and these are embedded in the flexible member 23. It is configured as follows. This triangle is desirably an equilateral triangle in order to perform polishing uniformly. The grindstone pieces 13a can be fixed so that the adjacent grindstone pieces are in close contact with each other without a gap. Further, a rectangular parallelepiped grinding wheel piece 13a can also be used.
[0030]
In the polishing grindstone 28 shown in FIG. 18, cylindrical grindstone pieces 13 are fixed to a wheel base at regular intervals so as to form a hexagon on the circular flexible member 23, and these are embedded in the flexible member 23. It is configured to: This hexagon is desirably a regular hexagon in order to perform polishing uniformly. The grindstone pieces 13 can also be fixed so that adjacent grindstone pieces are in close contact with each other without leaving an interval. Further, a rectangular parallelepiped grinding wheel piece 13a can also be used.
[0031]
The polishing grindstone 29 shown in FIG. 19 is an example in which grindstone pieces of various shapes are combined and fixed to the wheel base, and a ring-shaped grindstone piece 13b formed on the innermost side is fixed and the outermost side thereof is fixed. , Cylindrical grindstone pieces 13 are fixed in an annular shape at regular intervals, and further, on the outer peripheral side, rectangular parallelepiped grindstone pieces 13 a are fixed in a circular shape at regular intervals, and are attached to the circular flexible member 23. It is configured to be buried. In addition, the grindstone pieces 13, 13a, and 13b can be arbitrarily combined, and are not limited to the illustrated example. In addition, the grindstone pieces can be arranged in multiple layers.
[0032]
The various polishing wheels described above are mounted on, for example, a polishing apparatus 30 shown in FIG. In the following, a case where the polishing grindstone 10 shown in FIGS. 1 and 2 is mounted on the polishing apparatus 30 will be described as an example.
[0033]
In the polishing apparatus 30 shown in FIG. 20, for example, when polishing the surface of a semiconductor wafer, a plurality of semiconductor wafers to be polished are housed in a wafer cassette 31, carried out by carrying-in / out means 32, and placed on a positioning table 33. Is placed.
[0034]
After the alignment of the semiconductor wafer W is performed, the semiconductor wafer W is placed and held on the chuck table 35 by the first transfer means 34. The chuck table 35 is supported by a turntable 36 so as to be able to rotate and revolve. The chuck table 35 is positioned directly below the first grinding means 37 by rotating the turntable 36 by a required angle (120 degrees in the illustrated example).
[0035]
The first grinding means 37 is connected to a support plate 40 slidably engaged with a pair of guide rails 39 arranged in a direction perpendicular to the inner surface of the wall portion 38. A ball screw 42 connected to a pulse motor 41 is vertically disposed on the inner surface of the wall 38, and a nut (not shown) provided on a support plate 40 is screwed to the ball screw 42. The support plate 40 and the first grinding means 37 fixed thereto are moved up and down with the rotation of the ball screw 42 driven by the pulse motor 41.
[0036]
The first grinding means 37 includes a spindle 43 having a vertical axis, a motor 44 for driving the spindle 43 to rotate, a mounter 45 formed at the lower end of the spindle 43, and a grinding wheel 10 fixed to the mounter 45. And the grinding wheel 10 is configured as shown in FIGS. 1 and 2. As the grinding wheel piece 13 in this case, for example, a grinding wheel piece for rough grinding is used, and the grinding wheel 10 is also rotated by the rotation of the spindle 43. The first grinding means 37 rotates while the grinding wheel 10 rotates. Is lowered, and the rotating grinding wheel piece 13 and the flexible member 12 come into contact with the surface of the semiconductor wafer W to perform rough grinding.
[0037]
The roughly ground semiconductor wafer W is positioned directly below the second grinding means 46 by rotating the turntable 36 by a required angle (120 degrees in the illustrated example). The second grinding means 46 is connected to a support plate 48 slidably engaged with a pair of guide rails 47 disposed in a direction perpendicular to the inner surface of the wall 38. A ball screw 50 connected to a pulse motor 49 is vertically disposed on the inner surface of the wall 38, and a nut (not shown) provided on the support plate 48 is screwed to the ball screw 50. The support plate 48 and the second grinding means 46 fixed thereto are moved up and down as the ball screw 50 is rotated by being driven by the pulse motor 49.
[0038]
The second grinding means 46 includes a spindle 51 having a vertical axis, a motor 52 for driving the spindle 51 to rotate, a mounter 53 formed at a lower end of the spindle 51, and a grinding wheel 10 fixed to the mounter 53. And the grinding wheel 10 is configured as shown in FIGS. 1 and 2. As the grinding wheel piece 13 in this case, for example, a grinding wheel piece for finish grinding is used, and the polishing grindstone 10 is also rotated by the rotation of the spindle 51. The second grinding means 46 rotates while the polishing grindstone 10 rotates. Is lowered, and the rotating grinding wheel piece 13 and the flexible member 12 come into contact with the surface of the semiconductor wafer W to perform finish grinding.
[0039]
After finishing grinding, the chuck table 35 is moved to be positioned near the second transfer means 54, and the ground semiconductor wafer W is transferred to the cleaning means 55 by the second transfer means 54. Then, the semiconductor wafer W washed here is accommodated in the wafer cassette 56 by the carrying-in / out means 32.
[0040]
During the rough grinding and the finish grinding, the rotating flexible member 12 and the grindstone pieces 13 come into contact with the semiconductor wafer W at the same time, as shown in FIG. At this time, even when the flexible member 12 protrudes from the grindstone piece 13, since the flexible member 12 contracts due to the pressing force from above and becomes flush with the grindstone piece 13, this is illustrated in FIGS. 23 and 24. Unlike conventional grinding wheels, the contact area is large. Accordingly, the contact pressure of the grinding wheel 10 is reduced, and the load resistance applied to the spindle 43 (51) is reduced. Actually, when the silicon wafer was polished, the load current value of the motor for driving the spindle was 9.5 [A] in the conventional grinding wheel shown in FIGS. 23 and 24. The value of the load current of the motor 44 (52) was 7.5 [A], and it was confirmed that the value of the load current was significantly reduced and the load resistance was reduced. Therefore, polishing can be performed without causing surface burn, and the quality of the semiconductor wafer can be improved.
[0041]
As shown in FIG. 22, the wheel base 11 is provided with a plurality of polishing liquid outflow holes 11a communicating with a polishing liquid flow passage 43a (51a) formed inside the spindle 43 (51). When the polishing liquid is discharged from the hole 11a and wet polishing is performed, the flexible member 12 guides the polishing liquid evenly to the contact portion, and the frictional resistance is reduced by the polishing liquid, so that the polishing liquid is applied to the spindle 43 (51). The load is further reduced. In particular, this effect is remarkable when the flexible member 12 is formed of a material such as a felt through which the polishing liquid penetrates.
[0042]
Further, when abrasives such as diamond are included in the flexible member 12, polishing efficiency is improved in addition to the above-described effects.
[0043]
【The invention's effect】
As described above, in the polishing whetstone according to the present invention, since the flexible member is fixed at a position adjacent to the whetstone piece, the pressure applied to the whetstone piece during polishing is reduced, and it is possible to prevent the occurrence of surface burn. And the load on the spindle is reduced. Therefore, the quality of the object to be polished can be improved, and the life of the polishing apparatus can be prolonged.
[0044]
In addition, if abrasive grains are mixed in the flexible member, polishing can be performed more efficiently, and productivity is improved.
[0045]
Furthermore, when a polishing liquid outflow hole is provided in the wheel base, the polishing liquid flowing out from the polishing liquid outflow hole is uniformly guided by the flexible member to the contact portion between the grindstone piece and the plate-shaped object, so Such pressure is reduced, and the load on the spindle is further reduced. Therefore, the life of the polishing apparatus can be further extended.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a plane side of a first embodiment of a grinding wheel according to the present invention.
FIG. 2 is a perspective view showing a bottom surface side of the first embodiment of the grinding wheel.
FIG. 3 is a cross-sectional view showing a part of the polishing grindstone.
FIG. 4 is a sectional view showing a part of a second example of the polishing grindstone.
FIG. 5 is a bottom view showing a second embodiment of the grinding wheel.
FIG. 6 is a bottom view showing a third embodiment of the grinding wheel.
FIG. 7 is a bottom view showing a fourth embodiment of the polishing wheel.
FIG. 8 is a bottom view showing a fifth embodiment of the grinding wheel.
FIG. 9 is a bottom view showing a sixth embodiment of the polishing grindstone.
FIG. 10 is a bottom view showing a seventh embodiment of the grinding wheel.
FIG. 11 is a bottom view showing the eighth embodiment of the polishing wheel.
FIG. 12 is a bottom view showing a ninth embodiment of the polishing wheel.
FIG. 13 is a bottom view showing a tenth embodiment of the grinding wheel.
FIG. 14 is a bottom view showing the eleventh embodiment of the grinding wheel.
FIG. 15 is a bottom view showing a twelfth embodiment of the grinding wheel.
FIG. 16 is a bottom view showing a thirteenth embodiment of the grinding wheel.
FIG. 17 is a bottom view showing a fourteenth embodiment of the polishing grindstone.
FIG. 18 is a bottom view showing the fifteenth embodiment of the grinding wheel.
FIG. 19 is a bottom view showing a sixteenth embodiment of the grinding wheel.
FIG. 20 is a perspective view showing an example of an embodiment of a polishing apparatus on which the polishing grindstone is mounted.
FIG. 21 is a schematic cross-sectional view showing a state where a semiconductor wafer is polished using the polishing grindstone.
FIG. 22 is a schematic cross-sectional view showing a state where a semiconductor wafer is polished while a polishing liquid is supplied using a polishing grindstone.
FIG. 23 is a perspective view showing a conventional grinding wheel.
FIG. 24 is a front view showing a state in which a plate-like object is polished using the polishing grindstone.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Polishing whetstone 11 ... Wheel base 11a ... Polishing liquid outflow hole 12 ... Flexible member 13, 13a, 13b ... Whetstone pieces 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25, 26 , 27, 28, 29 ... Polishing grindstone 31 ... Wafer cassette 32 ... Carry-in / out means 33 ... Positioning table 34 ... First transport means 35 ... Chuck table 36 ... Turntable 37 ... Grinding means 38 ... Wall 39 ... Guide rail 40 ... Support plate 41 ... Pulse motor 42 ... Ball screw 43 ... Spindle 44 ... Motor 45 ... Mounter 46 ... Second grinding means 47 ... Guide rail 48 ... Support plate 49 ... Pulse motor 50 ... Ball screw 51 ... Spindle 52 ... Motor 53 ... Mounter 54: second transport means 55: cleaning means 56: wafer cassette

Claims (5)

A wheel grindstone having a wheel base and a grindstone piece fixed to an end surface of the wheel base,
A polishing whetstone, wherein a flexible member is fixed to an end surface of the wheel base at a position adjacent to the whetstone piece. The polishing whetstone according to claim 1, wherein the flexible member is disposed such that its exposed surface is flush with the exposed surface of the whetstone piece or protruded from the exposed surface of the whetstone piece. The polishing whetstone according to claim 1, wherein the flexible member includes abrasive grains. The polishing wheel according to claim 1, 2 or 3, wherein the flexible member is formed of felt. The polishing wheel according to claim 1, 2, 3, or 4, wherein the wheel base has a polishing liquid outflow hole through which the polishing liquid flows out.

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