JP2001191238A - Chamfering method for disc-like work, grinding wheel for chamfering and chamfering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chamfering technique for a disc-like work capable of excellently finishing an outer peripheral edge of the disc-like work, even if a width direction center of the disc-like work and a width direction center of a grinding wheel groove of a grinding wheel are slightly shifted to each other. SOLUTION: When an outer peripheral edge of wafer W is chamfered by using the three annular grinding wheel grooves 6a, 6b, 6c (or 6d) for rough grinding to finishing grinding which are provided on an outer periphery of a single grinding wheel 2, the sectional forms of the grinding wheel grooves 6a, 6b, 6c (or 6d) to be used for each of three-stage grinding processes from a rough grinding process to a finishing grinding process are set so that the opening widths may be larger than at least the width of wafer W and a round- shaped radius of curvature at the bottom part may be gradually smaller as the radius goes from the grinding wheel groove 6a for rough grinding to the grinding wheel groove 6c (or 6d) for finishing grinding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for chamfering a disk-shaped workpiece, a grinding wheel for chamfering, and a chamfering apparatus, and more particularly, to an outer peripheral edge of a thin disk-shaped workpiece such as a semiconductor silicon wafer. The present invention relates to a chamfering technique for chamfering.

[0002]

2. Description of the Related Art For example, a semiconductor silicon wafer (hereinafter, referred to as a semiconductor silicon wafer)
As a general technique for chamfering an outer peripheral edge of a wafer, there is a chamfering technique using a grinding wheel.

A grinding wheel used for this kind of chamfering has a disk-shaped grindstone base provided with an abrasive layer on the outer peripheral portion and a grindstone groove for chamfering on the cylindrical outer peripheral surface. . As the abrasive layer, generally, a metal bond abrasive layer formed by bonding diamond abrasive particles with a metal binder is employed.

As the diamond abrasive grains constituting the abrasive grain layer, grains having the same grain size are usually used, but two kinds having different grain sizes may be used in some cases.

When two types of abrasive grains having different grain sizes are used as described above, for example, the abrasive grain layer is divided into an abrasive grain layer having a coarse grain size and an abrasive grain layer having a fine grain size. In addition, a grindstone groove is provided in each of these abrasive grain layers.

In order to chamfer the outer peripheral edge of a wafer using a grinding wheel having such a structure,
First, the outer peripheral edge of the wafer is slid into contact with the grindstone groove of the coarse-grained abrasive layer to roughen the wafer, and then the wafer and the grinding wheel are relatively moved in the axial direction of the rotating spindle. The peripheral edge is slid in contact with the grindstone groove of the fine-grained grain layer to perform finishing.

In the method of chamfering the outer peripheral edge of the wafer with the grindstone grooves of the metal bond abrasive grain layer as described above, the processing accuracy of the surface of the grindstone grooves is low, and processing is performed using abrasive grains layers having different grain sizes. However, a sufficiently high-precision finishing cannot be performed. Because of this,
In the next step, the burden of mirror-finishing the chamfered portion of the wafer is increased, and this requires time and cost.

In this regard, attention has recently been paid to a resin-bonded abrasive layer formed by bonding diamond abrasive grains with a resin binder, which is said to have better surface processing accuracy than a metal-bonded abrasive layer. A grinding wheel has been proposed in which a resin bond abrasive layer and a metal bond abrasive layer are provided on the outer peripheral surface of a grinding wheel base (for example, Japanese Patent Application Laid-Open No. H11-28597).
No. 3).

In this grinding wheel, the resin bond abrasive grain layer and the metal bond abrasive grain layer are provided with the same grindstone grooves for chamfering as described above, and the metal bond abrasive grain layer is rough-grained. The particle size of the resin bond abrasive layer is finer than that of the metal bond abrasive layer.

[0010] Then, after the outer peripheral edge of the wafer is brought into sliding contact with the grindstone groove of the metal bond abrasive grain layer to perform rough processing, the outer peripheral edge of the roughly processed wafer is brought into sliding contact with the grindstone groove of the resin bond abrasive grain layer. By performing the finishing process, the processing time and cost are reduced.

Further, by providing a plurality of grindstone grooves in the resin bond abrasive grain layer having a shorter life than the metal bond abrasive grain layer, when the groove shape of the resin bond abrasive grain layer is out of shape,
The life of the whole grinding wheel is prolonged by chamfering by using the grindstone groove of another resin bond abrasive layer.

[0012]

However, since each of the grinding wheel grooves provided in the above-mentioned conventional grinding wheel has the same cross-sectional shape, the relative positioning accuracy between the grinding wheel and the wafer is limited. In the case where the center between the width direction of the wafer and the center in the width direction of each grindstone groove is displaced, the following problem occurs.

For example, after rough finishing is performed with the center in the width direction of the wafer shifted downward with respect to the center in the width direction of the grinding wheel groove of the grinding wheel, the center in the width direction of the wafer is then adjusted to the center of the grinding wheel groove. If the finishing process is performed in a state of being shifted upward with respect to the center in the width direction, the lower half portion of the outer peripheral edge of the wafer in the width direction cannot be sufficiently finished in the finishing process with a small amount of grinding compared to the rough finishing process. Occurs.

If the outer peripheral edge of the wafer cannot be sufficiently finished as described above, the mirror processing in the next step will be burdensome, as described above, and as a result, the processing time and cost cannot be reduced. .

For this reason, conventionally, high precision is required for the relative positioning between the grinding wheel and the wafer,
The reality is that high costs have been spent on the production of devices that meet this demand.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to slightly displace the center of the disk-shaped work in the width direction and the center of the grinding wheel groove in the width direction of the grinding wheel. Another object of the present invention is to provide a disk-shaped work chamfering technique capable of satisfactorily finishing the outer peripheral edge of the disk-shaped work.

[0017]

In order to achieve the above object, a method of chamfering a disk-shaped work according to the present invention comprises a plurality of annular workpieces from a rough grinding to a finish grinding, which are arranged coaxially and rotate. A method of chamfering the outer peripheral edge of a disk-shaped work using a grindstone groove, wherein a cross-sectional shape of the grindstone groove used in each of a plurality of grinding steps from a rough grinding step to a finish grinding step has an opening width Is larger than at least the width of the disk-shaped work, and the radius of curvature of the R-shape at the bottom thereof is set so as to gradually decrease as going from the grindstone groove for rough grinding to the grindstone groove for finish grinding. .

Further, the grinding wheel for chamfering a disk-shaped work of the present invention is used for carrying out the above-described chamfering method, and has a plurality of annular rings from rough grinding to finish grinding on the outer periphery. It comprises a grinding wheel groove, the cross-sectional shape of the grinding wheel groove used in each of a plurality of grinding steps from the rough grinding process to the finish grinding process, the opening width is at least larger than the width of the disk-shaped workpiece, and The radius of curvature of the R-shape at the bottom is set so as to gradually decrease from the grindstone groove for rough grinding to the grindstone groove for finish grinding.

The apparatus for chamfering a disk-shaped work according to the present invention is also used for carrying out the above-mentioned chamfering method, and has a plurality of grindstone grooves on the outer periphery for rough grinding to finish grinding. A single grinding wheel that is rotationally driven, and relative moving means for relatively moving this grinding wheel with respect to the disk-shaped workpiece that is held in rotation, comprising: The cross-sectional shape of the plurality of grindstone grooves up to grinding is set so as to sequentially change within a range of a grinding allowance in a grinding process in which the grindstone grooves are used.

As a preferred embodiment, in each of the above-mentioned grindstone grooves, when the radius of curvature of the R-shape of the groove bottom is twice smaller than the groove opening width, the groove side surface from the bottom to the opening end is cut by the disk. The tapered surface is equal to the final tapered shape of the outer peripheral edge of the workpiece. In addition, at least two types of abrasive layers having different particle sizes are formed on the outer peripheral surface of the grinding wheel, and at least one of the abrasive grooves is provided in each of the abrasive layers, and the finer particles are formed. The radius of curvature of the R shape at the bottom of the grinding wheel groove provided in the abrasive layer is:
The radius is set to be smaller than the radius of curvature of the R shape at the bottom of the grindstone groove provided in the coarse grain layer.

The fine-grained abrasive layer is a resin-bonded abrasive layer formed by bonding abrasive grains with a resin binder, and the coarse-grained abrasive layer is formed by bonding abrasive grains to metal. A metal bond abrasive grain layer bonded by an agent, wherein the resin bond abrasive grain layer is provided with at least two grinding stone grooves.

In the present invention, for example, the shape of a plurality of grinding wheel grooves provided on the outer periphery of a single grinding wheel is devised, that is, each of the plurality of grinding steps from a rough grinding step to a finish grinding step is performed. The cross-sectional shape of the grindstone groove to be used is such that the opening width is at least larger than the width of the disc-shaped work, and the radius of curvature of the R shape at the bottom goes from the grindstone groove for rough grinding to the grindstone groove for finish grinding. By setting so as to become gradually smaller according to, even if the center in the width direction of the disc-shaped work and the center in the width direction of the grindstone groove for grinding the outer peripheral edge of the disc-shaped work are slightly shifted,
The outer peripheral edge of the disc-shaped work can be satisfactorily finished, the burden of mirror finishing in the next step is reduced, and the relative positioning accuracy between the grinding wheel and the work is relaxed.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a disk-shaped workpiece processing apparatus according to the present invention. Specifically, this processing apparatus is a grinding apparatus for chamfering an outer peripheral edge of a semiconductor silicon wafer (hereinafter, simply referred to as a wafer) W. It is. That is, the processing of the outer peripheral edge of the wafer W is performed in two stages, namely, a grinding process for chamfering the outer peripheral edge of the wafer W and a polishing process for mirror-finishing the ground chamfered portion. In order to reduce the load in the polishing process of
This is applied to the former grinding performed as a processing step in the preceding stage.

The main part of the grinding apparatus is a work holding portion 1 for rotating and holding a wafer W, and a grinding wheel 2 for chamfering the outer peripheral edge of the wafer W held by the work holding portion 1. .

The work holding unit 1 is in the form of a rotary table that can be horizontally rotated through a rotary support shaft 3 and has a holding structure for removably holding and fixing the wafer W on its upper surface. Although not specifically shown, the holding structure of the work holding unit 1 is in the form of a vacuum chuck that sucks and holds the wafer W, has a plurality of suction holes on its horizontal upper surface, and these suction holes are not shown. Is connected to a negative pressure source. In addition, the rotation support shaft 3 which is vertically supported,
It is drivingly connected to a rotary drive source (not shown).

The grinding wheel 2 is arranged so as to be horizontally rotatable via a vertical rotating spindle 5 as shown in the figure.
The cylindrical outer peripheral portion is provided with a plurality (four in the illustrated case) of annular grinding stone grooves 6a to 6d for rough grinding to finish grinding.

Specifically, this grinding wheel 2 is shown in FIGS.
As shown in FIG. 4, an abrasive layer 8 is provided on an outer peripheral portion of a disk-shaped grindstone base 7, and the abrasive layer 8 is formed of a metal bond abrasive layer 8a laminated in the axial direction and a resin bond abrasive layer. And a grain layer 8b. The metal bond abrasive layer 8a is formed by bonding diamond abrasive grains with a metal binder, and the resin bond abrasive layer 8b is formed by bonding diamond abrasive grains with a resin binder.

In the illustrated embodiment, the two abrasive grain layers 8a and 8b are provided on the outer peripheral portion of the integrated grindstone base 7.
Are laminated in the axial direction of the grinding wheel 2, two independent grinding wheels are formed using independent grinding wheel bases for the respective abrasive grain layers 8 a and 8 b, and both grinding wheels are formed. May be integrally fixed in the axial direction in a laminated manner.

The metal bond abrasive grain layer 8a is formed of coarse abrasive grains having a coarse grain size. On the other hand, as shown in FIG. 4, the resin bond abrasive grain layer 8b is further divided into two types of abrasive grain layers 8b ₁ and 8b ₂ having different grain sizes. The first resin bond abrasive grain layer 8b ₁
Together are formed by abrasive grains for the finish grinding into finer granularity than the metal bond abrasive layer 8a, the second resin bonded abrasive grain layer 8b ₂ is further formed with abrasive for fine finish grinding particle size I have.

In the illustrated embodiment, No. 1 in Table 1 is used.
As shown in FIG.
Formed by the diamond abrasive grains, while the first resin-bonded abrasive layer 8b ₁ granularity of resin bonded abrasive grain layer 8b # 2
2,000 diamond abrasive grains and the second
Resin bond abrasive layer 8b ₂ of is formed by diamond abrasive grains of grain size ♯4000.

[0032]

[Table 1]

On the peripheral surface of the metal bond abrasive grain layer 8a,
The grinding wheel groove 6a is formed in an annular shape over the entire circumference,
This grindstone groove 6a is for rough grinding. The first resin circumferential surface of the bond abrasive layer 8b _1, wherein the grinding wheel groove 6b is formed in an annular shape over the entire circumference, the grinding wheel groove 6b is a for medium finish grinding. In addition, the peripheral surface of the second resin-bonded abrasive layer abrasive layer 8b _2, the grinding wheel groove 6c and 6
d is formed in an annular shape over the entire circumference of the two rows, and these grindstone grooves 6c and 6d are used for finish grinding.

From the rough grinding to the finish grinding, 4
The two grindstone grooves 6a to 6d have a structure in which the upper and lower ends of the outer peripheral edge of the wafer W are chamfered at the same time, and their cross-sectional shapes are sequentially reduced within a grinding allowance in a grinding process in which the grindstone grooves are used. It is set to change.

That is, as shown in FIG. 4, the grindstone grooves 6a to 6d with respect to the outer peripheral surface of each abrasive grain layer have a depth D.
Are set to the same size (for example, 0.55 mm), while the cross-sectional shape of each of the grindstone grooves 6a to 6d is such that the opening width is at least larger than the width of the wafer W, and the radius of curvature of the R shape at the bottom thereof is Is set so as to gradually decrease from the grindstone groove 6a for rough grinding to the grindstone grooves 6c and 6d for finish grinding, and is designed to have a shape suitable for the grinding process assigned to each grindstone groove.

More specifically, the cross-sectional shape of the grinding wheel groove 6a for rough grinding is such that its bottom is formed in an R shape having a radius of curvature R1 having the same length as the depth D of the above-described grinding wheel groove, that is, in an arc shape. The cross-sectional shape of the entire grindstone groove 6a is formed in a semicircular shape.

The cross-sectional shape of the grinding stone groove 6b for semi-finishing grinding is such that its bottom is formed into an R shape having a radius of curvature R2 smaller than the radius of curvature R1 of the bottom of the grinding stone groove 6a, and from this bottom to the opening end. The continuous upper and lower sides are formed as tapered surfaces having a predetermined angle α.

Each of the cross-sectional shapes of the grinding wheel groove 6c and the grinding wheel groove 6d for finish grinding has an R-shape having a radius of curvature R3 (for example, 0.37 mm) whose bottom is slightly smaller than the radius of curvature R2 of the bottom of the grinding wheel groove 6b. And the upper and lower sides continuous with the bottom have the same angle α as the grinding wheel groove 6b.
It is formed on a tapered surface having That is, in the second resin bond abrasive grain layer 8b2 of the resin bond abrasive grain layer 8b, _two grindstone grooves 6c and 6d having exactly the same cross-sectional shape are formed. The other one is used for this one grindstone groove 6c.
Or, it is a spare when 6d is worn.

The taper (taper angle α) of the groove side surface of each of the grinding stone grooves 6b to 6d is equal to the taper of the final taper shape of the outer peripheral edge of the wafer W. The opening width of the grindstone grooves 6b to 6d is set to be smaller than the opening width of the grindstone groove 6a, that is, the radius of curvature of the bottom R-shape.

With such a groove configuration, even if the center in the width direction of the wafer W and the center in the width direction of each of the grindstone grooves 6b to 6d are slightly displaced in the grinding step described later, the outer peripheral edge of the wafer W Extremely uneven grinding of both ends is effectively prevented. That is, these grindstone grooves 6a to 6d
Can be inserted into the outer peripheral edge of the wafer W to be chamfered,
In addition, the upper and lower ends are set to have a shape and a size that can be chamfered simultaneously and uniformly. When the cross-sections of the grinding wheel grooves 6a to 6d are overlapped with each other, the cross-sectional shape has a relationship as shown in FIG.

Therefore, a plurality of grinding stone grooves 6a, 6b, 6c (or 6d) having different shapes and materials are provided.
The outer peripheral edge of the wafer W is sequentially inserted and slid and ground while being ground in a procedure described later, so that the upper and lower ends of the outer peripheral edge of the wafer W are chamfered at the same time. When the cross sections of the outer peripheral edge of the wafer W ground by the grindstone grooves 6a to 6d are overlapped with each other and compared with each other, these cross sectional shapes are shown in FIG.
The relationship is as shown in FIG.

A mounting hole 9 is provided in the center of the grinding wheel base 7 of the grinding wheel 2, and the grinding wheel 2 is removably mounted on the rotary spindle 5 through the mounting hole 9. Fixed.

Further, the grinding wheel 2 and the work holding unit 1 configured to horizontally rotate and hold the wafer W, which are configured as described above, are relatively movable in the vertical and horizontal directions, respectively. The peripheral edge and the outer peripheral surface of the grinding wheel 2 are configured to approach or separate from each other.

In the illustrated embodiment, the grinding wheel 2
A grinding wheel base (not shown) that rotationally supports the rotating spindle 5 moves in both the vertical direction Y and the horizontal direction X with respect to the workpiece holding unit 1 so that the outer peripheral edge of the wafer W is The centering positioning in the axial direction, that is, the vertical direction Y with respect to the grindstone grooves 6a to 6d, and the cutting feed operation in the cutting direction, that is, the horizontal direction X, with respect to each of the grindstone grooves 6a to 6d are performed.

Next, a description will be given of a method of chamfering the outer peripheral edge of the wafer W by the grinding apparatus configured as described above.

(1) Rough grinding step: As shown in FIG. 1, the wafer W rotating at a low speed while being suction-held by the work holding unit 1
The grinding wheel 2 which rotates at a high speed with respect to the outer peripheral edge of the wafer W is moved and arranged so that the grinding wheel groove 6a for rough grinding is opposed to the outer peripheral edge of the grinding wheel 2. Is done.

As a result, the outer peripheral edge of the wafer W is cut into the grindstone groove 6a relatively by a predetermined amount, and the angular outer peripheral edge of the wafer W indicated by the two-dot chain line in FIG. While being chamfered into a shape along the curved surface (R1), it is roughly ground into a shape shown by a solid line in FIG.

(2) Medium finishing grinding step: When the rough grinding step is completed, the grinding wheel 2 is separated from the outer peripheral edge of the wafer W in the horizontal direction X, and the outer peripheral edge of the wafer W After this, the grinding wheel 2 is moved and arranged so that the grinding wheel groove 6b for medium finishing grinding faces the outer peripheral edge of the wafer W. 2 is cut and fed to the outer peripheral edge of the wafer W.

As a result, the outer peripheral edge of the wafer W is cut into the above-mentioned grindstone groove 6b by a predetermined amount, and follows the shape of the curved surface (R2) at the bottom of the grindstone groove 6b and the tapered surface formed at the angle α. While being chamfered into the shape shown in FIG.

(3) Finish grinding step: When the intermediate finish grinding step is completed, the grinding wheel 2 is separated from the outer peripheral edge of the wafer W in the horizontal direction X, and the outer peripheral edge of the wafer W After relatively detaching from the groove 6b, this time, the grinding wheel 2 is moved and arranged so that the grinding wheel groove 6c (or 6d) for finish grinding faces the outer peripheral edge of the wafer W. Thereafter, the grinding wheel 2 is cut and fed to the outer peripheral edge of the wafer W.

As a result, the outer peripheral edge of the wafer W is cut relatively by a predetermined amount into the grinding wheel groove 6c, and follows the shape of the curved surface (R3) at the bottom of the grinding wheel groove 6c and the tapered surface formed at the angle α. While being chamfered into the shape, the shape is finish-ground to the shape shown by the two-dot chain line in FIG.

Thus, by the above-described grinding process,
By chamfering the outer peripheral edge of the wafer W, the wafer W
Is formed in such a manner that the grinding allowance in each processing is secured in advance by each of the grinding stone grooves 6a to 33 having different cross-sectional shapes, and the center in the width direction of the wafer W and the width direction center of each of the grinding stone grooves 6a to 33 are aligned. Even if there is some deviation, within the above-mentioned grinding allowance, the semi-finishing and finishing grinding of the outer peripheral edge of the wafer W can be satisfactorily performed as a whole.

By the way, as in the prior art, although the material and the grain size are different, if the shape of each grindstone groove itself is the same,
As described above, the following processing defects occur due to no grinding allowance due to the shape of the grinding wheel groove.

For example, after rough grinding is performed in a state where the center in the width direction of the wafer W is shifted downward with respect to the center in the width direction of the grindstone groove, the center of the wafer W in the width direction is changed to the width of the grindstone groove. If the finish grinding is performed in a state of being shifted upward with respect to the center of the direction, the lower end portion of the outer peripheral edge of the wafer W cannot be finish-ground sufficiently in the finish grinding with a smaller grinding amount as compared with the rough grinding. Things will happen.

As described above, in the conventional processing apparatus, the center in the width direction of the wafer W and the center in the width direction of each grinding wheel groove need to be positioned with high precision.
By devising the cross-sectional shapes of 6 to 6c (or 6d), the positioning accuracy of the center in the width direction of the wafer W and the center in the width direction of each of the grindstone grooves 6a to 6c (or 6d) can be relaxed.

The second resin bond abrasive grain layer 8b
Resin-bonded abrasive layer 8b ₂ the formed finish grinding for grinding wheel grooves 6c, 6d, the groove shape of shape as compared with the grinding wheel groove 6a and semi-finish grinding for the 6b for other rough grinding Easy to do. Therefore, as described above, the grinding wheel grooves 6c and 6d
Is used first for finish grinding, while the other is left as a spare, and when the above one grindstone groove 6c or 6d is out of shape, the other spare grindstone groove 6d or 6c is used. Thus, the outer peripheral edge of the wafer W is subjected to finish grinding.

By forming a plurality of grinding wheel grooves in which the groove shape is likely to be out of shape in this manner, the life of the grinding wheel 2 itself can be extended, and the grinding wheel 2 can be used efficiently. And the frequency of replacement can be reduced.

The above-described embodiment merely shows a preferred embodiment of the present invention, and the present invention is not limited to this, and various design changes can be made within the scope.

For example, in the illustrated embodiment, the number of grindstone grooves formed in each abrasive grain layer is one for rough grinding, one for medium finish grinding, and two for finish grinding. However, the present invention is not limited to this, and an appropriate number may be formed in consideration of the life of each abrasive grain layer.

Incidentally, in order to extend the life of the grinding wheel 2 itself, one piece for rough finishing and two pieces for medium finishing are used.
It has been experimentally found that it is preferable to use four pieces for finishing and four pieces for finishing.

In the illustrated embodiment, the particle size is about 800
Grindstone groove 6a in metal bond abrasive grain layer 8a formed of
And an abrasive layer 8b ₁ to grindstone groove 6b of the abrasive grains in the formed resin bond abrasive layer 8b granularity # 2000, further granularity ♯4
Abrasive layer 8b ₂ to grinding groove 6c of resin bonded abrasive grain layer 8b formed in the abrasive grain 000 has been described as having a 6d, but the combination of the abrasive grain layer and particle size to provide a grinding wheel groove 6a~6d is It is optional, and the design is appropriately changed according to the purpose.

As an example, as shown in FIG. As shown in FIG. 2, the metal bond abrasive layer was made to have a particle size of # 800 and a particle size of # 200.
A resin bond formed with abrasive grains having a grain size of ０００4000, and a grindstone groove 6a provided in an abrasive layer having a grain size of 、 800, and a grindstone groove 6b formed in an abrasive grain layer having a grain size of ♯200. The grindstone grooves 6c and 6d may be provided in the abrasive grain layer.

The abrasive layer of the grinding wheel 2 is as follows.
The following configurations can also be employed.

A fine-grained abrasive layer is a resin-bonded abrasive layer formed by bonding abrasive grains with a resin binder, and a coarse-grained abrasive layer is formed by bonding abrasive grains by vitrified bond. A vitrified bond abrasive grain layer, wherein the resin bond abrasive grain layer has at least two grindstone grooves.

A fine-grained abrasive layer is a vitrified bond abrasive layer formed by bonding abrasive grains with vitrified bonds, and a coarse-grained abrasive layer is formed by bonding abrasive grains with a metal binder. A metal bond abrasive grain layer, wherein at least two grindstone grooves are provided in the vitrified bond abrasive grain layer.

A grindstone groove for finish grinding is provided in a resin bond abrasive layer formed by bonding abrasive grains with a resin binder, and a grindstone groove for medium finish grinding is bonded to abrasive grains by vitrified bond. A vitrified bond abrasive grain layer, and a grindstone groove for finish grinding provided in a metal bond abrasive grain layer formed by bonding abrasive grains with a metal binder.

[0067]

As described above, according to the present invention, a plurality of annular grindstone grooves for rough grinding to finish grinding are arranged coaxially and rotated to form a disk-shaped workpiece. When chamfering the outer peripheral edge, the cross-sectional shape of the grindstone groove used in each of a plurality of grinding steps from the rough grinding step to the finish grinding step, the opening width is at least larger than the width of the disk-shaped work, and the Since the radius of curvature of the R-shape at the bottom is set so as to gradually decrease from the grindstone groove for rough grinding to the grindstone groove for finish grinding, the center in the width direction of the disk-shaped work and the outer peripheral edge of the disk-shaped work are set. Even if the center of the grinding wheel groove in the width direction is slightly misaligned, the outer peripheral edge of the disk-shaped work can be finished well, reducing the burden of mirror finishing in the next process, and at the same time as the grinding wheel. It can be relaxed relative positioning accuracy between.

For example, after the outer peripheral edge of a disk-shaped work is first roughly ground by a grindstone groove provided in a coarse-grained abrasive layer,
When finishing grinding with a grindstone groove provided in a fine grain layer, the radius of curvature of the bottom of the grindstone groove provided in the fine grain layer is adjusted to a radius of curvature of the bottom of the grindstone layer provided in the coarse grain layer. When the radius of curvature of the bottom R shape is smaller than the opening width in each grinding wheel groove, the groove side surface from the bottom to the opening end of the disc-shaped work is made smaller than the radius of curvature of the bottom R shape. By making the tapered surface equal to the final tapered shape of the outer peripheral edge, the finishing processing is performed in a state where the grinding margin of the outer peripheral edge of the disk-shaped work by each grindstone groove is secured in advance.

Thus, even if the center in the width direction of the disc-shaped work and the center in the width direction of the grindstone groove are slightly shifted, the finishing process can be performed satisfactorily, and the burden on the mirror finishing in the next step is reduced. In addition, the overall processing time and cost can be reduced, and the relative positioning accuracy between the grinding wheel and the workpiece can be reduced.

Further, by forming both side surfaces of the grindstone groove provided in the fine grain layer on the same tapered surface as the final tapered shape of the outer peripheral edge of the disk-shaped work, the grinding allowance is further increased and both sides are formed. Surface can be secured evenly,
The effects described above can be further enhanced.

Further, the fine-grained abrasive layer is used as a resin-bonded abrasive layer, the coarse-grained abrasive layer is used as a metal-bonded abrasive layer, and at least two grindstone grooves are provided in the resin-bonded abrasive layer. The outer peripheral edge of the disc-shaped work can be finished with high precision using the bond abrasive layer, and when the groove shape of the resin bond abrasive layer that has a short life is out of shape, the finish processing is performed with the next new grinding wheel groove. It can be carried out.

As a result, the life of the entire grinding wheel can be prolonged, the number of replacement steps of the grinding wheel can be reduced, and
Reduction of grinding wheel cost is realized.

[Brief description of the drawings]

FIG. 1 is a front view showing a schematic configuration of a main part of a disk-shaped workpiece processing apparatus according to an embodiment of the present invention in a partial cross section.

FIG. 2 is a sectional view showing a grinding wheel as a main part of the processing apparatus.

FIG. 3 is a plan view showing the same grinding wheel.

FIG. 4 is an enlarged sectional view showing an abrasive layer of the grinding wheel.

FIG. 5 is an enlarged sectional view showing each grinding wheel groove formed on the outer peripheral surface of each abrasive grain layer of the grinding wheel in a superimposed manner.

FIG. 6 is an enlarged cross-sectional view showing an outer peripheral edge of a disc-shaped work overlapped with each other when processed by each grinding wheel groove of the grinding wheel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Work holding part 2 Grinding wheel 3 Rotation spindle of a work holding part 5 Rotating spindle of a grinding wheel 6a-6d Grindstone groove 8 Abrasive layer 8a Metal bond abrasive layer 8b Resin bond abrasive layer 8b ₁ First resin Bond abrasive layer 8b ₂ Second resin bond abrasive layer W Semiconductor silicon wafer (disk-shaped work)

Claims (11)

[Claims] 1. Using a plurality of annular grindstone grooves, which are arranged coaxially and rotate, for rough grinding to finish grinding,
A method of chamfering an outer peripheral edge of a disk-shaped workpiece, wherein a cross-sectional shape of each of the grindstone grooves used in each of a plurality of stages of grinding processes from a rough grinding process to a finish grinding process has an opening width of at least the disk shape. Larger than the width of the workpiece,
A chamfering method for a disk-shaped workpiece, wherein a radius of curvature of an R shape at a bottom thereof is set so as to gradually decrease from a grinding wheel groove for rough grinding to a grinding wheel groove for finish grinding. 2. In each of the grinding wheel grooves, R
When twice the radius of curvature of the shape is smaller than the groove opening width, the groove side surface from the bottom to the opening end has a tapered surface equal to the final tapered shape of the outer peripheral edge of the disk-shaped workpiece. The method for chamfering a disk-shaped workpiece according to claim 1. 3. A grinding wheel for chamfering, comprising a plurality of annular grindstone grooves for rough grinding to finish grinding on an outer periphery for chamfering an outer peripheral edge of a disk-shaped workpiece. From the cross-sectional shape of the grindstone groove used in each of a plurality of grinding steps from the finish grinding step, the opening width is larger than at least the width of the disk-shaped workpiece,
A grinding wheel for chamfering a disk-shaped workpiece, wherein a radius of curvature of an R shape at a bottom thereof is set so as to gradually decrease from a grinding wheel groove for rough grinding to a grinding wheel groove for finish grinding. . 4. In each of the grinding wheel grooves, R
When twice the radius of curvature of the shape is smaller than the groove opening width, the groove side surface from the bottom to the opening end has a tapered surface equal to the final tapered shape of the outer peripheral edge of the disk-shaped workpiece. The grinding wheel for chamfering a disk-shaped workpiece according to claim 3. 5. At least two types of abrasive layers having different grain sizes are formed on the outer periphery, and at least one of the abrasive stone grooves is provided in each of the abrasive layers. The radius of curvature of the R-shape at the bottom of the grindstone groove provided in the layer is set to be smaller than the radius of curvature of the R-shape at the bottom of the grindstone groove provided in the coarse-grained abrasive layer. The chamfering apparatus for a disk-shaped workpiece according to claim 3 or 4, wherein: 6. The abrasive grain layer having a fine grain size is a resin-bonded abrasive grain layer in which abrasive grains are bonded with a binder of a resin, and the coarse grain abrasive layer is a layer in which abrasive grains are bonded to a metal. 6. The disk-shaped workpiece according to claim 5, wherein the resin-bonded abrasive layer is provided with at least two of the grindstone grooves. apparatus. 7. The fine-grained abrasive layer is a resin-bonded abrasive layer formed by bonding abrasive grains with a resin binder, and the coarse-grained abrasive layer is formed by vitrified bond of abrasive grains. The apparatus according to claim 5, wherein the vitrified bond abrasive grain layer is combined, and the resin bond abrasive grain layer is provided with at least two of the grindstone grooves. 8. The fine-grained abrasive layer is a vitrified bond abrasive layer formed by bonding abrasive grains with vitrified bonds, and the coarse-grained abrasive layer is formed by using an abrasive with a metal binder. 6. A bonded metal bond abrasive grain layer, wherein the vitrified bond abrasive grain layer is provided with at least two of the grindstone grooves.
2. The apparatus for processing a disk-shaped workpiece according to claim 1. 9. The grinding wheel groove for finish grinding is provided on a resin bond abrasive layer formed by bonding abrasive grains with a resin binder, and the grinding wheel groove for medium finishing grinding is formed by vitrified bond. Wherein the grindstone grooves for finish grinding are provided in a metal bond abrasive grain layer in which the abrasive grains are combined with a metal binder. An apparatus for processing a disk-shaped workpiece according to any one of claims 3 to 5. 10. A single grinding wheel which is provided with a plurality of grindstone grooves for rough grinding to finish grinding on its outer periphery and is driven to rotate, and this grinding wheel is used for a disk-shaped workpiece which is rotatably held. Relative movement means for relatively moving with respect to, the cross-sectional shape of the plurality of grinding stone grooves from the rough grinding to the finish grinding, the opening width is at least larger than the width of the disk-shaped workpiece. A chamfering apparatus for a disk-shaped workpiece, wherein a radius of curvature of an R shape at a bottom portion thereof is set to be gradually reduced from a grinding wheel groove for rough grinding to a grinding wheel groove for finish grinding. 11. The apparatus for chamfering a disk-shaped workpiece according to claim 10, wherein the grinding wheel has the structure according to any one of claims 3 to 9.