JP2001246551A - Polishing apparatus and polishing method - Google Patents

Abstract

An object of the present invention is to suppress excessive polishing of an outer peripheral end of a surface to be polished of an object to be polished such as a semiconductor wafer and to optimize a state of a polished surface of a polishing tool during polishing. A polishing apparatus and a polishing method are provided. A polishing apparatus for polishing a surface to be polished by relatively moving a surface to be polished of a wafer W as a member to be polished and a polishing surface 8a of a polishing tool 8 while pressing each other, the polishing surface of the polishing tool 8 being provided. 8a, and has a pressing surface 102 which can be pressed against the surface 8a, and is separated from the outer periphery of the polished surface of the wafer W so that relative rotation occurs between the pressing surface 102 and the polished surface of the wafer W. And a protection member 91 for suppressing excessive polishing of the outer peripheral end of the wafer W provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polishing apparatus and a polishing method.

[0002]

2. Description of the Related Art As semiconductor devices become more highly integrated and multi-layered, flattening of various interlayer insulating films or other films becomes more important in the process of manufacturing semiconductor devices. Various means have been proposed as a technique for planarization. In recent years, a CMP (Chemical Mechanical Polishing) method which applies a mirror polishing technique of a silicon wafer has attracted attention and is utilized. A method for flattening has been developed. FIG. 24 shows an example of a polishing apparatus using the CMP method. Polishing device 301 shown in FIG.
Has a main spindle 303 for rotating a cylindrical polishing tool 302 and a table 304 for holding a wafer W. The table 304 is rotatably mounted on a slider 306 provided movably in the X-axis direction along a rail 305, and is rotatably driven by a rotary drive unit including, for example, a motor, a pulley, a belt, and the like. Is done. The main spindle 303 is held movably in the Z-axis direction, and is positioned at a target position in the Z-axis direction by a drive mechanism (not shown). Polishing device 3 having the above configuration
In FIG. 01, first, the wafer W is rotated at a predetermined rotation speed, and a slurry as an abrasive obtained by mixing abrasive grains such as silicon oxide with a liquid such as an aqueous solution of potassium hydroxide is not shown on the wafer W. The slurry is supplied onto the wafer W from the slurry supply device. Next, the wafer W and the polishing tool 302 are rotated in the X-axis and Z-axis directions so that the polishing tool 302 is rotated at a predetermined number of revolutions, and the outer peripheral edge of the polishing tool 302 overlaps and comes into contact with the outer peripheral edge of the wafer W. Is positioned. The polishing tool 302 is positioned in the Z-axis direction so as to have a predetermined cutting amount with respect to the wafer W,
As a result, a predetermined processing pressure is generated between the polishing tool 302 and the wafer W. In this state, the wafer W is moved in the X-axis direction at a predetermined speed pattern, and the polishing tool 30 is moved.
While the wafer 2 is in contact with the wafer W, the wafer W is polished and the wafer W is flattened.

[0003]

By the way, the polishing tool 3
Reference numeral 02 denotes an elastic body formed of a ring-shaped member and formed of a resin such as polyurethane foam. The polishing tool 302 is pressed against the surface of the wafer W at a predetermined processing pressure. Therefore, the polishing tool 302 pressed against the wafer W is elastically deformed. Further, as shown in FIG. 25, when the polishing tool 302 rotating in the direction of the arrow R1 moves in the processing progress direction D with respect to the wafer W rotating in the direction of the arrow R2 opposite to the arrow R1, the polishing tool 302 Circle A
The region indicated by runs over the wafer W from outside the wafer W. In this riding region, the polishing tool 302
For example, as shown in FIG.
The polishing surface 302a of the polishing tool 302 is elastically deformed because the polishing surface 302a of the polishing tool 302 rides on the surface of the wafer W from the outer peripheral edge EG of the wafer W, and the polishing just before the polishing surface 302a rides on the surface of the wafer W located near the outer peripheral edge EG. The surface 302a
The wafer W is projected downward from the surface of the wafer W.
When the polishing surface 302a of the polishing tool 302 is elastically deformed as described above, the portion of the polishing surface 302a protruding downward with respect to the surface of the wafer W comes into strong contact with the outer peripheral end EG of the wafer W, and most of the processing energy. Is used for the operation in which the protruding portion of the polishing surface 302a rides on the outer peripheral edge EG of the wafer W, and damages the outer peripheral edge of the wafer W. On the other hand, in a region where the polishing tool 302 indicated by a circle B in FIG.
As shown in FIG. 26B, the polishing surface 3 of the polishing tool 302
02a is separated from the surface of the wafer W through the outer peripheral end EG, so that the polishing surface 3 of the polishing tool 302 elastically deformed.
02a is separated from the outer peripheral end EG of the wafer W, and the deformation is restored while the stress is relaxed. For this reason, in a region where the polishing tool 302 escapes from the inside of the wafer W to the outside of the wafer W, the outer peripheral edge of the wafer W is hardly damaged.

When damage to the outer peripheral edge EG of the wafer W due to the protruding portion of the polishing surface 302a as described above is accumulated, the wafer W is rotated.
As shown in FIG. 27, an excessively polished portion 352 that is excessively polished is formed in the entire outer peripheral portion of the wafer W. When the excessively polished portion 352 is formed, the number of semiconductor chips formed on one wafer W is reduced, and there is a disadvantage that the yield is reduced. In addition, the processing energy is consumed for excessive polishing of the outer peripheral end portion EG of the wafer W,
The polishing rate, which is the removal amount of the surface of the wafer W per unit time, is reduced, the number of processed wafers W per unit time is reduced, and the productivity is reduced. Also, the polishing tool 302
In the region where the polished surface 302a runs on the outer peripheral edge EG of the wafer W, the polished surface 302a is greatly damaged,
The quality of the polished surface 302a is apt to be rapidly deteriorated, so that the processing conditions are liable to change. It is necessary to condition the polishing surface 302a by means of dressing or the like in order to prevent fluctuations in the processing conditions, and if the frequency of conditioning is increased in order to make the state of the polishing surface 302a appropriate, the productivity of the polishing apparatus will decrease. There were disadvantages.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a polishing method capable of suppressing excessive polishing of the outer peripheral edge of a surface to be polished of a body to be polished such as a semiconductor wafer. An object of the present invention is to provide an apparatus and a polishing method. Another object of the present invention is to provide a polishing apparatus and a polishing method capable of optimizing a state of a polishing surface of a polishing tool during polishing.

[0006]

According to a first aspect of the present invention, there is provided a polishing apparatus for polishing a polished surface by relatively moving a polished surface of a polished body and a polished surface of a polishing tool while pressing the polished surface with each other. A polishing device having a pressing surface that can be pressed against the polishing surface of the polishing tool, and a relative movement occurs between the pressing surface and the surface to be polished of the object to be polished. A protection member is provided at the periphery of the surface to be polished of the body to be polished so as to suppress excessive polishing of the peripheral end of the surface to be polished.

In a polishing apparatus according to a first aspect of the present invention, the protective member is movably held in a direction substantially perpendicular to a polishing surface of the polishing tool, and a pressing surface of the protective member. And pressing means for pressing the polishing tool against the polishing surface of the polishing tool.

A polishing apparatus according to a second aspect of the present invention includes a holding table for rotatably holding the object to be polished, rotation holding means for rotatably holding the polishing tool, and a rotating table for rotating the object to be polished. A relative moving means for relatively moving in the radial direction while pressing the surface to be polished and the polishing surface of the rotating polishing tool, comprising a pressing surface which can be pressed against the polishing surface of the polishing tool. And the polished object provided so that relative movement occurs between the pressing surface and the polished surface of the polished object at a position separated from the outer periphery of the polished surface of the polished object. A protective member for suppressing excessive polishing of the outer peripheral end of the surface is provided.

Preferably, a rotation axis of the polishing tool is inclined at a predetermined angle in a direction perpendicular to a holding surface of the holding table toward a traveling direction of the polishing tool. Is in contact with the surface to be polished of the object to be polished.

[0010] More preferably, the polishing tool has an annular polishing surface.

A polishing apparatus according to a second aspect of the present invention further comprises abrasive supply means for supplying an abrasive interposed between a polishing surface of the polishing tool and a surface to be polished of the object to be polished.

In a polishing apparatus according to a second aspect of the present invention, the protective member is movably held in a direction substantially perpendicular to a polishing surface of the polishing tool, and a pressing surface of the protective member. And pressing means for pressing the polishing tool against the polishing surface of the polishing tool.

Preferably, the pressing means comprises: holding means for holding the protection member rotatably about an axis parallel to a direction of relative movement between the polishing tool and the object to be polished; Drive means for rotating about an axis.

More preferably, the driving means includes an air cylinder having a built-in piston rod rotatably connected to the protection member, and rotating the protection member about the axis by expansion and contraction of the piston rod. Is done.

In a polishing apparatus according to a second aspect of the present invention, the pressing force generated by the driving unit is adjusted so that the pressure of the pressing surface against the polishing surface is constant. There is a pressing force control means for controlling according to the distance between the position and the axis.

The pressing means guides the protection member movably in a direction perpendicular to the polishing surface of the polishing tool, and moves the protection member in a direction perpendicular to the polishing surface of the polishing tool. It is also possible to adopt a configuration having driving means.

The driving means may be constituted by an air cylinder.

Preferably, the gap between the inner peripheral edge of the pressing surface of the protective member and the outer peripheral edge of the polished surface of the polished body can suppress excessive polishing of the outer peripheral end of the polished surface. Is set to a predetermined value.

The pressing surface of the protective member can be brought into contact with the polishing surface at least at a position before the polishing surface of the rotating polishing tool rides on the surface to be polished from the outside of the surface to be polished of the object to be polished. Is provided.

The protection member is provided at a position separated by a predetermined gap from the outer periphery of the rotating object to be polished in a state where rotation is regulated.

Preferably, the pressing surface of the protection member is formed by an annular surface or a part of the annular surface along the surface to be polished of the object to be polished.

More preferably, the pressing surface of the protective member surrounds one half of the outer periphery of the surface to be polished of the object to be polished along the direction of relative movement between the polishing tool and the object to be polished. Are located.

Preferably, at least the pressing surface of the protection member is formed of a material harder than the polishing tool.

More preferably, the polishing tool is formed of a material having a foamable resin material as a base material, and the protective member is formed of a ceramic material.

[0025] At least a part of the pressing surface of the protection member may be formed of a material for dressing the polishing surface of the polishing tool.

[0026] At least a part of the pressing surface of the protection member may be formed with irregularities for dressing the polishing surface of the polishing tool.

The pressing surface of the protective member is configured to remove foreign substances adhering to the polishing surface due to contact with the polishing surface of the polishing tool or a deteriorated layer of the polishing surface, or to dress the polishing surface. be able to.

Preferably, the pressing surface of the protection member substantially presses the polishing surface of the polishing tool at the inner peripheral portion on the side of the object to be polished, and adheres to the polishing surface substantially at the outer peripheral edge portion. Removal of foreign matter or a deteriorated layer of the polished surface or dressing of the polished surface is performed.

A polishing method according to a first aspect of the present invention is a polishing method for polishing the surface to be polished by relatively moving the surface to be polished of the object to be polished and the surface of the polishing tool while pressing them against each other. A protection member having a pressing surface which can be pressed against the polishing surface of the polishing tool is provided on the outer periphery of the surface to be polished of the object to be polished, and the pressing surface of the protection member is provided with a predetermined pressing force by the polishing tool. Pressing against the polishing surface to generate a relative movement between the pressing surface and the surface to be polished of the object to be polished, the polishing surface of the polishing tool, the surface to be polished of the object to be polished, and the protective member The surface to be polished is polished while relatively moving the pressing surface.

A polishing apparatus according to a second aspect of the present invention comprises: a holding table for rotatably holding the object to be polished; rotation holding means for rotatably holding the polishing tool; Relative movement means for relatively moving in a radial direction while pressing the surface to be polished and the polishing surface of the rotating polishing tool, the polishing method in a polishing apparatus, wherein the pressing can be pressed against the polishing surface of the polishing tool A protective member having a surface is provided at a position separated from the outer periphery of the polished surface of the object to be polished so that relative movement occurs between the pressing surface and the polished surface of the object to be polished; Excessive polishing of the outer peripheral edge of the polishing surface is suppressed.

According to the present invention, the polished surface of the polished body is polished while pressing the pressing surface of the protective member disposed on the outer periphery of the polished body against the polished surface of the polishing tool, thereby elastically deforming the polished surface of the polishing tool. This suppresses concentration of stress on the outer peripheral end of the object to be polished, and suppresses excessive polishing of the outer peripheral end of the polished surface of the object to be polished. At this time, by generating relative rotation between the protection member and the object to be polished, the pressing surface of the protection member and the polishing surface of the polishing tool relatively move during polishing, so that the pressing of the protection member is performed. Dimensional errors such as surface flatness and height variations and assembly errors are suppressed from being transferred to the outer peripheral edge of the polished surface of the object to be polished as it is, and the outer peripheral edge of the polished surface of the object to be polished is suppressed. Processing accuracy is improved.

Furthermore, according to the present invention, in addition to pressing the polishing surface of the polishing tool with the pressing surface of the protective member to suppress excessive polishing of the outer peripheral end portion of the object to be polished, the polishing surface of the polishing tool and the pressing surface To remove foreign substances adhering to the polished surface due to contact with the polished surface or the deteriorated layer of the polished surface, or to dress the polished surface. In particular, by pressing the pressing surface of the protective member before the polishing surface of the polishing tool rides on the surface to be polished from the outside of the surface to be polished of the polishing object, foreign matter adhering to the polishing surface of the polishing tool is reduced. The transport to the surface to be polished is regulated by the outer peripheral edge portion, and the occurrence of a defect such as a scratch on the surface to be polished due to the foreign matter being carried to the surface to be polished is suppressed. Similarly,
Removal of the deteriorated layer on the polished surface on the pressing surface of the protective member, or
By dressing the polished surface, it is possible to prevent the material forming the removed deteriorated layer and the polishing tool from entering the polished surface of the object to be polished.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a polishing apparatus according to a first embodiment of the present invention. The polishing apparatus 1 shown in FIG. 1 includes a polishing tool 8, a spindle spindle 21 for rotating and holding the polishing tool 8, a Z-axis moving mechanism 11 for moving and positioning the spindle spindle 21 in the Z-axis direction, and a wafer W for holding and rotating. And an X-axis moving mechanism 51 that moves the holding table 41 in the X-axis direction. The main spindle 21 and the Z-axis moving mechanism 1
Reference numeral 1 denotes a rotation holding means of the present invention, and the X-axis moving mechanism 51 and the Z-axis moving mechanism 11 constitute a relative moving means of the present invention.

The main spindle 21 holds the polishing tool 8, and rotates the polishing tool 8 about the rotation axis K1. The spindle 21 incorporates therein a spindle 23, a hydrostatic bearing for rotatably holding the spindle 23, and a servomotor for rotating the spindle 22. Also,
The main spindle 21 is held by a spindle holder 20. The spindle holder 20 is movably held on the column 3 by a guide (not shown) along the Z-axis direction. Further, a slurry / pure water supply nozzle 81 for supplying slurry as slurry and pure water onto the wafer W is provided at a predetermined position on the outer periphery of the main spindle 21.
Is provided.

The Z-axis moving mechanism 11 is provided along the Z-axis direction (vertical direction) on the portal column 3 erected on the base 2 so that the main spindle 21 can be moved in the Z-axis direction. keeping. The Z-axis moving mechanism 11 holds the polishing surface 8a of the polishing tool 8 in a direction facing the surface to be polished of the wafer W, and determines the relative position of the polishing surface 8a in the facing direction to the surface to be polished of the wafer W. Specifically, the Z-axis moving mechanism 11 includes a servo motor 12 fixed to the column 3.
And a screw shaft 13 formed with a screw connected to the servomotor 12, and a Z-axis slider 14 formed with a screw portion to be screwed with the screw shaft 13 and connected to the spindle holder 20. By driving the servo motor 12 to rotate, the Z-axis slider 14 moves up or down along the Z-axis direction, and the spindle holder 20 connected to the Z-axis slider 14 moves up or down along the Z-axis direction. Thus, by controlling the amount of rotation of the servomotor 12, the polishing tool 8 can be positioned in the Z-axis direction.

The holding table 41 is provided with a holding plate 41a provided in parallel with the horizontal direction for holding a wafer W as an object to be polished. The wafer W is held on the holding plate 41a by, for example, chucking means such as vacuum suction. Chucking by. The holding table 41 is provided with, for example, a driving unit such as a motor, and
To rotate. The holding table 41 corresponds to a specific example of the holding table of the present invention. A collection pan 82 for collecting the slurry supplied from the slurry / pure water nozzle 81 onto the wafer W is provided around the holding table 41. Slurry / pure water nozzle 81
Corresponds to a specific example of the abrasive supply means of the present invention.

The X-axis moving mechanism 51 includes a servo motor 55
And a screw shaft 54 formed with a screw connected to the servomotor 55, an X-axis slider 53 formed with a screw portion screwed to the screw shaft 54, and an X-axis slider 53 connected to the X-axis slider 53.
An X-axis table 52, which is movably held in the axial direction by a guide (not shown) and on which the above-described holding table 41 is installed, is provided. The X-axis moving mechanism 51 holds the holding table 41 and functions as a relative moving unit of the present invention for relatively moving the polishing tool 8 and the wafer W along the holding plate 41a of the holding table 41. That is, by driving the servo motor 55 to rotate, X
The axis slider 53 moves in any direction in the X-axis direction,
The X-axis table 52 also moves in any direction in the X-axis direction, and the holding plate 41a of the holding table 41 moves in any direction in the X-axis direction along the horizontal plane. It relatively moves along the holding plate 41a of the holding table 41.

The polishing tool 8 is a cylindrical member fixed to the lower end surface of the main shaft 22 and made of an elastic body which is elastically deformed when pressed against the wafer W. As a material for forming the polishing tool 8, for example, a resin such as foamable polyurethane, or a material obtained by solidifying fixed abrasive grains made of, for example, cerium oxide (CeO ₂ ) with a soft binder can be used. As the soft binder, for example, a melamine resin, a urethane resin, or a phenol resin can be used. The polishing tool 8 has an annular end surface parallel to a plane perpendicular to the rotation axis K1 on the lower end surface of the cylindrical member,
This becomes the polished surface 8a for processing the polished surface of the wafer W. When polishing a wafer having a diameter of 8 inches, the polishing tool 8 is, for example, 200 × 20 × 20.
(Mm) can be used. That is, the diameter of the wafer W and the outer diameter of the polishing tool 8 are substantially the same.

FIG. 2 is provided between the main spindle 21 and the spindle holder 20 of the polishing apparatus 1 having the above-described configuration.
FIG. 7 is a diagram for explaining a rotation axis tilting mechanism that adjusts a tilt amount of a rotation axis K1 of a spindle spindle 21 (polishing tool 8) with respect to an axis K2 perpendicular to a holding plate 41a of a holding table 41. In FIG. 2, a flange 24 is formed on the outer periphery of the spindle 21. The insertion shaft portion 27 above the flange portion 24 of the spindle spindle 21 is a parallel portion at a position close to the flange portion 24, and has a tapered surface tapering upward. The fitting hole 20b of the spindle holder 20 is fitted and inserted into the spindle holder 20. The rotating shaft tilting mechanism 61 is provided between the upper end surface 24 a of the flange 24 formed on the outer periphery of the main spindle 21 and the lower end surface 20 a of the spindle holder 20. The rotation axis tilting mechanism 61 includes, for example,
It is provided at three places located at equal intervals in the circumferential direction of the flange portion 24.

The upper end surface 24a of the flange portion 24 is a surface parallel to a plane perpendicular to the rotation axis K1 of the spindle spindle 21 (polishing tool 8). In addition, the rotating shaft tilting mechanism 61 includes 2
There are two tilt adjusting blocks 62 and 63.
The tilt adjusting block 62 and the tilt adjusting block 6
By adjusting the relative positional relationship with the spindle 3, the distance between the upper end surface 24a of the flange portion 24 of the main spindle 21 and the lower end surface 20a of the spindle holder 20 can be adjusted. Therefore, by adjusting the rotation axis tilt mechanisms 61 provided at three locations, the tilt angle of the rotation axis K1 of the spindle spindle 21 (polishing tool 8) with respect to the axis K2 perpendicular to the holding plate 41a of the rotary table 41 can be set to any value. And can be inclined in any direction.

FIG. 3 is a plan view showing the structure around the holding table 41 of the polishing apparatus 1. FIG. 4 is a side view as viewed from the direction of arrow J in FIG. 3, and FIG. 5 is a cross-sectional view along the line EE in FIG. As shown in FIGS. 3 to 5, the upper surface of the base BS on the outer periphery of the wafer W held by the holding table 41 is provided for suppressing excessive polishing of the outer peripheral edge generated when the wafer W is polished. Protection member 9
1 is provided.

The protection member 91 is composed of the polishing tool 8 and the wafer W.
And a semi-cylindrical guard portion 101 arranged so as to surround one half of the outer periphery of the wafer W in the direction of relative movement with respect to. Further, as shown by a circle F shown in FIG. 3, the protection member 91 is provided with a polishing surface 8a of the polishing tool 8 which rotates in the direction of the arrow R1.
This is arranged on the side where the wafer W rotating in the opposite direction (arrow R2) runs over the outer peripheral end.

The protection member 91 is provided on the upper surface 1 of the guard portion 101.
Reference numeral 02 denotes a pressing surface that can be pressed against the polishing surface 8a of the polishing tool 8. The pressing surface 102 is constituted by a part of an annular surface along the periphery of the wafer W, and is a smooth surface. Further, the guard portion 101 of the protection member 91 includes:
Since the rotation is regulated at a position separated by a predetermined gap d from the outer periphery of the wafer W rotating on the upper surface of the base BS, the rotation is regulated, so that a relative position is formed between the pressing surface 102 and the surface to be polished of the wafer W. Rotation occurs.

The protection member 91 has support shafts 92 at both ends along the X-axis direction. The support shafts 92 are rotatably supported by support columns 93 erected on the upper surface of the base BS. I have. That is, the protection member 91 is held rotatably about an axis AX parallel to the X-axis direction which is the direction of relative movement between the polishing tool 8 and the wafer W. Thereby, the pressing surface 102 of the guard portion 101 of the protection member 91
Is movable in the directions of arrows Z1 and Z2 shown in FIG. 5 which are directions substantially perpendicular to the polishing surface 8a of the polishing tool 8. Note that the support shaft 92 and the support column 93 constitute a holding unit of the present invention.

On the base BS, there are provided two predetermined air sinders 94 as driving means of the present invention.
The air cylinder 94 has a built-in piston rod 95 driven by compressed air. The protection member 91 is rotatably connected to a piston rod 95 of the air cylinder 94 by a connection shaft 95a. Thereby, the protection member 9
1 rotates around a support shaft 92 in accordance with expansion and contraction of a piston rod 95 of an air cylinder 94. For example, as shown in FIG. 6, when the piston rod 95 of the air cylinder 94 is extended, the protection member 91 rotates in the direction of the arrow M. Since the rotation angle of the protection member 91 is actually very small, the pressing surface 102 of the protection member 91 moves substantially in the direction of arrow Z1. By moving the pressing surface 102 of the protection member 91 in the direction of the arrow Z1, the pressing surface 102 comes into contact with the polishing surface 8a of the polishing tool 8, and the pressing surface 102 presses the polishing surface 8a of the polishing tool 8. Note that the air cylinder 94 and the support shaft 92
The support means 93 constitutes the pressing means of the present invention.

A gap d is formed between the inner peripheral edge of the pressing surface 102 of the protective member 91 and the outer peripheral edge of the wafer W. The gap d is set to a predetermined value so that excessive polishing of the outer peripheral end of the surface to be polished of the wafer W can be suppressed. That is, if the value of the gap d is too large, the effect of suppressing excessive polishing of the outer peripheral edge of the wafer W by the pressing surface 102 cannot be obtained, so the gap d is preferably as small as possible. However, since the protection member 91 pivots about the support shaft 92, the clearance d between the inner peripheral edge of the pressing surface 102 of the protective member 91 and the outer peripheral edge of the wafer W is correspondingly changed.
Changes. For this reason, if the gap d is too small, the pressing surface 1
02 and the outer peripheral edge of the wafer W may interfere with each other. Therefore, the gap d is formed between the pressing surface 102 and the wafer W.
It is necessary to set the optimum value within a range where the outer peripheral edge does not interfere with the outer peripheral portion, for example, a range where the interference does not exceed 0.5 mm.

The material for forming the protection member 91 is not particularly limited, but the material for forming at least the pressing surface 102 of the protection member 91 is formed of a material harder than the polishing tool 8. As described above, the polishing tool 8 is formed of, for example, a material having a foamable resin material as a base material, and the protection member 91 or the guard portion 101 of the protection member 91 can be formed of a ceramic material.

FIG. 7 is a configuration diagram showing an example of the configuration of the control system of the air cylinder 94. In FIG. 7, the control system of the air cylinder 94 includes a control device 151 and a control valve 15.
2 is provided. Note that the control device 151 and the control valve 152 constitute a pressing force control unit of the present invention. The control valve 152 controls the compressed air AR supplied to the air cylinder 94.
Command 151 output from the controller 151 to the pressure of
Adjust according to s. The control device 151 applies the pressing force generated on the piston rod 95 of the air cylinder 94 to the polishing surface 8a and the pressing surface so that the pressure of the pressing surface 102 of the protective member 91 against the polishing surface 8a of the polishing tool 8 becomes substantially constant. A control command 151s for controlling according to the distance between the contact position of the surface 8a and the axis AX is output to the control valve 152.

As shown in FIG. 8, when the polishing tool 8 and the wafer W are relatively moved along the X-axis, the contact position of the pressing surface 102 of the protection member 91 in contact with the polishing surface 8a of the polishing tool 8 becomes PA. , PB, PC. For example,
Assuming that the pressing force generated by the air cylinder 94 is constant, the pressing surface 1 of the protection member 91 is applied to the polishing surface 8 a of the polishing tool 8.
The pressure acting from 02 differs at each of the contact locations PA, PB and PC. Since the distances LA, LB, and LC between the axis AX at which the protection member 91 rotates and the contact positions PA, PB, and PC are different from each other, even if the pressing force generated by the air cylinder 94 is constant, polishing is performed at each contact position. The pressure acting on the polishing surface 8a of the tool 8 from the pressing surface 102 of the protection member 91 changes according to the distances LA, LB and LC. Therefore, at each of the contact positions PA, PB and PC, the polishing tool 8
In order to make the pressure acting on the polishing surface 8a of the protection member 91 from the pressing surface 102 constant, the pressing force generated in the air cylinder 94 is adjusted according to the distance between the contact position and the axis AX.

The distance between the contact point between the polishing surface 8a of the polishing tool 8 and the pressing surface 102 of the protective member 91 and the axis AX is the position in the X-axis direction of the holding table 41, that is, the servo motor in the X-axis moving mechanism 51. It can be specified based on the 55 rotation amount information. Therefore, the control device 151 specifies the distance between the contact position of the polishing surface 8a and the pressing surface 102 and the axis AX from the position information Sw of the holding table 41 in the X-axis direction. The controller 151 controls the polishing surface 8a and the pressing surface 10a.
2 from the distance between the contact position 2 and the axis AX.
Is generated and output to the control valve 152 as a control command 151s.

Next, a polishing method of the present invention using the polishing apparatus 1 having the above-described configuration will be described. First, the rotation axis tilting mechanism 61 of the polishing apparatus 1 is adjusted so that the rotation axis K1 of the polishing tool 8 is adjusted.
Is tilted at a predetermined angle in a direction perpendicular to a plane parallel to the holding plate 41 a of the rotary table 41 in the direction in which the polishing tool 8 advances. Specifically, as shown in FIG.
The rotation axis K1 of the polishing tool 8 is set to an axis O perpendicular to a plane (XY plane) parallel to the holding plate 41a of the rotation table 41.
With respect to the wafer W of the polishing tool 8 with respect to the wafer W (the direction in which polishing proceeds) at an angle α. When the wafer W has a diameter of 8 inches, the inclination angle α of the rotation axis K1 of the polishing tool 8 is, for example, Z at the front and rear ends of the polishing surface 8a of the polishing tool 8 shown in FIG. The height difference Hα in the axial direction is 15 to 50 μm
Set to a value of the order. That is, the inclination angle is about 15 to 50 μm with respect to the length of 8 inches. The polishing surface 8a of the polishing tool 8 is faced at an angle corresponding to the inclination angle α of the rotation axis K1, and the polishing surface 8a of the polishing tool 8 contacts the wafer W substantially in parallel.

Next, in the polishing apparatus 1 in which the rotation axis K1 is inclined at the inclination angle α, as shown in FIG.
a, and the rotary table 41 and the polishing tool 8 are rotated. The rotation direction R1 of the polishing tool 8
And the rotation direction R2 of the wafer W are reversed.

Further, as shown in FIG.
Is discharged onto the wafer W from the slurry / pure water supply nozzle 81. It should be noted that the slurry SL is always replenished by a necessary amount even during polishing. The slurry is not particularly limited. For example, a slurry in which silica-based fumed silica and high-purity ceria are suspended in an aqueous solution based on potassium hydroxide is used for an oxide film, and an abrasive is polished in alumina for a wiring metal. A mixture obtained by mixing a solvent having an oxidizing power with a working fluid formed as abrasive grains can be used.

Next, the polishing tool 8 is lowered in the Z-axis direction, and as shown in FIG. 9, the outer peripheral end of the polishing surface 8a of the polishing tool 8 located outside the wafer W is positioned at the outer peripheral end of the polishing tool 8; It is assumed that the processing start point P1 on the outer peripheral edge of the wafer W and the outer peripheral edge of the polishing tool 8 overlap each other.

Next, the polishing tool 8 is pressed against the wafer W, and the wafer W is brought into rotational contact with the polishing surface 8a of the polishing tool 8 while applying the processing pressure F in a direction perpendicular to the surface to be polished of the wafer W. At this time, since the rotation axis of the polishing tool 8 is inclined at an angle α with respect to the surface of the wafer W, the polished surface 8a comes into contact with the surface of the wafer W instead of the entire surface. At this time, the polishing surface 8a of the polishing tool 8 has an angle α
The polishing surface 8a contacts the surface of the wafer W substantially in parallel. When the polishing tool 8 is inclined and brought into contact with the surface of the wafer W, the polishing tool 8 is an elastic body.
a is elastically deformed. At this time, the polishing surface 8a of the polishing tool 8
The shape of the effective action area on the surface to be polished of the wafer W is substantially crescent-shaped, and the area of the effective action area is reduced. Even if the polishing tool 8 moves relatively in the X-axis direction, the area of this region is substantially constant. Therefore, the amount of polishing in the effective working area can be made uniform, and the polishing rate can be made constant. Further, by inclining the polishing tool 8, the polishing surface 8a of the polishing tool 8 becomes the wafer W
The slurry easily enters the space between the surfaces, and a sufficient amount of slurry can be supplied. Further, by adjusting the inclination angle and the polishing pressure of the polishing tool 8, the shape and the area of the effective action area can be adjusted, and the action area having an arbitrary shape and area can be obtained.

At the same time, the air cylinder 94 is driven to press the pressing surface 102 of the protection member 91 against the polishing surface 8a of the polishing tool 8 so that the air acting on the polishing surface 8a of the pressing surface 102 has a predetermined value. The pressing force generated by the cylinder 94 is controlled. At this time, at least a part of the region Sa where the pressing surface 102 shown in FIG. 10 overlaps the polishing surface 8a is in contact with the polishing surface 8a.

In this state, the X-axis table 52 is driven to move the wafer W from the processing start point P1 to the arrow C at which the overlapping area of the wafer W and the polishing tool 8 relatively increases.
In a predetermined speed pattern. Thus, the polishing tool 8 relatively advances in the radial direction of the wafer W. When the polishing tool 8 is moved relative to the wafer W after the polishing surface 8a of the polishing tool 8 is brought into contact with the processing start point P1 of the wafer W at the start of polishing, the processing pressure F When the polishing tool 8 reaches a predetermined position with respect to the wafer W, the processing pressure F is set to a constant value and polishing is performed. The speed pattern of the polishing tool 8 in the X-axis direction is adjusted in advance so that the polishing amount in the plane of the wafer W becomes uniform.

When the polishing tool 8 is relatively moved in the direction of arrow D, as shown in FIG. 11, the contact area Sa between the polishing surface 8a of the polishing tool 8 and the pressing surface 102 of the protection member 91 also moves. When the contact area Sa moves, the axis AX and the contact area S
The controller 151 responds to the change in the distance by the air cylinder 94 so that the pressure acting on the pressing surface 102 against the polishing surface 8a of the polishing tool 8 becomes constant. Controlling pressure.

A circle H shown in FIG. 11 indicates a region where the polishing surface 8a of the polishing tool 8 runs from the outside of the surface to be polished of the wafer W to the outer peripheral end of the surface to be polished. As can be seen from the position of the contact area Sa, the pressing surface 102 of the protection member 91 is
Before the polishing surface 8a of the polishing tool 8 rides on the outer peripheral edge of the surface to be polished from outside the surface to be polished of the wafer W, the polishing surface 8a
And presses the polishing surface 8 a of the polishing tool 8.

FIG. 12A is a view showing the state of the polishing tool 8 in the riding area shown in the circle H, and FIG.
Shows a state where the protection member 91 is not provided on the outer periphery of the wafer W. As shown in FIG. 12B, when the polishing surface 8a of the polishing tool 8 directly rides on the outer peripheral edge EG of the wafer W, the polishing surface 8a of the polishing tool 8 undergoes elastic deformation, and the outer peripheral edge of the wafer W The EG is damaged by the elastic deformation of the polishing tool 8. On the other hand, as shown in FIG.
The guard portion 101 of the protection member 91 is located just before the polishing surface 8a of the polishing tool 8 rides on the outer peripheral end EG of the wafer W. The polishing surface 8a of the polishing tool 8
Is elastically deformed by riding on the outer peripheral edge of the pressing surface 102, but since the pressing surface 102 is pressed, the deformation is restored when riding on the outer peripheral end EG of the wafer W. For this reason, the outer peripheral end portion EG of the wafer W is prevented from being damaged by the elastic deformation of the polishing tool 8, and excessive polishing is suppressed. further,
If the gap d between the inner circumference of the pressing surface 102 of the protection member 91 and the outer circumference of the wafer W is large, when the polishing surface 8a of the polishing tool 8 rides on the pressing surface 102 of the protection member 91, Elastic deformation occurs again and the outer peripheral edge E of the wafer W
G may be damaged, but this can be prevented since the gap d is set to an appropriate value as described above.

Further, the protection member 91 provided on the outer periphery of the wafer W is provided on the base BS in a state where the rotation thereof is regulated, and the pressing surface 102 of the protection member 91 and the surface to be polished of the wafer W are formed. There is a relative rotation between them. Therefore, the relative position between the pressing surface 102 of the protection member 91 and the surface to be polished of the wafer W is constantly changing during the polishing. For example, if it is assumed that the wafer W and the pressing surface 102 are rotating in synchronization, the protection member 91
If there is a position error in the unevenness and height on the pressing surface 102 of
The polishing surface 8a of the polishing tool 8 riding on the pressing surface 102
Is deformed following the unevenness and the position error, the outer peripheral end EG of the wafer W is also polished into a shape corresponding to the unevenness and the position error of the pressing surface 102, and polishing unevenness occurs. On the other hand, if the relative position between the pressing surface 102 of the protection member 91 and the surface to be polished of the wafer W is constantly changing, the protection member 9
The polishing surface 8a of the polishing tool 8 riding on the pressing surface 102 even if there is unevenness or a positional error in the pressing surface 102 of the first pressing surface 102.
Are uniformed, and the occurrence of polishing unevenness at the outer peripheral edge EG of the wafer W is suppressed.

Further, even if the pressing surface 102 of the protective member 91 has a positional error in the unevenness and the height, the working pressure of the pressing surface 102 of the protective member 91 on the polishing surface 8a of the polishing tool 8 is always constant. Since the pressing surface 102 is maintained, the height of the pressing surface 102 of the protection member 91 is automatically adjusted according to the unevenness and the position error, and the occurrence of polishing unevenness at the outer peripheral edge EG of the wafer W is further suppressed.

The pressing surface 102 of the protection member 91 has an effect of suppressing excessive polishing of the outer peripheral end of the wafer W and an effect of optimizing the state of the polishing surface 8a of the polishing tool 8. During the polishing process, for example, FIG.
As shown in (1), foreign matter T is generated from the wafer W and the polishing tool 8, and the foreign matter T adheres to the polishing surface 8a of the polishing tool 8. When the foreign matter T adheres to the polishing surface 8a of the polishing tool 8, the polishing surface 8a is clogged, and the polishing efficiency tends to decrease. Further, the foreign matter T attached to the polishing surface 8a of the polishing tool 8 is transported to the surface of the wafer W by the rotating polishing surface 8a,
Intervening between the polished surface 8a and the surface of the wafer W may cause scratches on the surface of the wafer W.

On the other hand, as shown in FIG. 13A, when the pressing surface 102 of the protective member 91 is pressed against the polishing surface 8a of the polishing tool 8, foreign matter T adhered to the polishing surface 8a of the polishing tool 8 is removed. 102 to remove. In particular, the outer peripheral edge 102a of the pressing surface 102 of the protection member 91 is
The foreign matter T attached to the polishing surface 8a of the polishing tool 8 riding on the workpiece 2 is positively removed. Therefore, the pressing surface 102 of the protection member 91 substantially presses the polishing surface 8a of the polishing tool 8 at the inner peripheral portion on the wafer W side, and the outer peripheral portion 1
At step 02a, the foreign matter T attached to the polished surface 8a is removed. By such an action, the wafer W
The foreign matter T that is going to enter the surface to be polished can be removed beforehand. Further, the pressing surface 102 of the protection member 91 is
Is constantly pressed against the polished surface 8a at a constant pressure, so that the removal rate of the foreign matter T is also constant, and the influence on the polished surface of the wafer W hardly varies.

During the polishing process, for example, FIG.
As shown in (b), the altered layer Lc is easily formed on the polishing surface 8a of the polishing tool 8 by a chemical reaction of the slurry SL or the like. When the altered layer Lc is formed, disadvantages such as a decrease in polishing efficiency occur. In order to remove the altered layer Lc, it is necessary to interrupt the polishing process and correct the polished surface 8a of the polishing tool 8 with a device such as a dresser.

On the other hand, as shown in FIG. 14A, by pressing the pressing surface 102 of the protective member 91 against the polishing surface 8a of the polishing tool 8, the deteriorated layer Lc formed on the polishing surface 8a of the polishing tool 8 is formed. It is removed by the pressing surface 102 of the protection member 91, especially by the outer peripheral edge 102 a.

Further, as the polishing process progresses, for example, as shown in FIG.
a tends to be rough, and if polishing is continued in such a state where the polished surface 8a is rough, the quality of the polished surface of the wafer W is degraded.

On the other hand, as shown in FIG. 15A, by pressing the pressing surface 102 of the protective member 91 against the polishing surface 8a of the polishing tool 8, the outer peripheral edge 102a of the pressing surface 102 While polishing the surface 8a, the polishing surface 8a of the polishing tool 8 is dressed to create a smooth surface. Further, since the pressing surface 102 of the protection member 91 is constantly pressed against the polishing surface 8a of the polishing tool 8 with a constant pressure, the quality of the dressed polishing surface 8a of the dressing polishing tool 8 is also stabilized.

Further, the pressing surface 102 of the protection member 91 is
In addition to the effect of suppressing excessive polishing of the outer peripheral edge of the wafer W and the effect of optimizing the state of the polishing surface 8a of the polishing tool 8,
This has an effect of appropriately adjusting the amount of the slurry SL permeating the polishing tool 8. For example, a foaming resin material such as melamine resin or urethane is used for the polishing tool 8. The slurry SL containing the abrasive grains supplied onto the wafer W is infiltrated into the polishing tool 8, and Polishing is performed. From the viewpoint of the quality of the surface to be polished of the wafer W, it is desirable that the amount of the slurry SL permeated into the polishing tool 8 be constant, that is, the amount of the abrasive grains permeated into the polishing tool 8 be constant. . However, for example, FIG.
As shown in (b), if the pressing surface 102 of the protection member 91 is not used, the amount of the abrasive grains Tr that penetrates the polishing tool 8 can only be adjusted by adjusting the amount of the slurry SL supplied onto the wafer W. There is no.

On the other hand, as shown in FIG. 16A, the pressing surface 102 of the protective member 91 is pressed against the polishing surface 8a of the polishing tool 8 at a constant pressure, so that the polishing surface 8a and the pressing surface 102 are pressed.
Is limited to a constant amount of the abrasive grains Tr passing through,
Excessive abrasive grains Tr are removed from the wafer W by the pressing surface 102.
Is restricted from entering the surface to be polished. Thereby, the amount of the abrasive grains Tr that penetrates into the polishing tool 8 is appropriately adjusted, and the quality of the polished surface of the wafer W can be improved.

As described above, polishing by the polishing tool 8 is performed along the traveling direction D while excessive polishing of the outer peripheral end of the wafer W is suppressed. The outer peripheral end of the polishing tool 8 is shown in FIG. The processing end point P2 of the wafer W is reached. When the outer peripheral edge of the polishing tool 8 moves to the processing end point P2 of the wafer W, the processing of the polished surface of the wafer W is completed. The polishing is completed by raising the polishing tool 8 in the Z-axis direction.

As described above, in the present embodiment, excessive polishing of the outer peripheral edge of the wafer W caused by stress concentration due to elastic deformation of the polishing surface 8a of the polishing tool 8 can be suppressed, and excessive polishing can be suppressed. The effect can be maintained for a long time. For example, in order to suppress excessive polishing of the outer peripheral end of the wafer W, a retainer ring 200 is provided instead of the protection member 91 on the outer periphery of the wafer W as shown in FIG. A method of rotating in the direction of arrow R2 in synchronization with the wafer W and the polishing surface of the polishing tool 8 rotating in the direction of arrow R1 against the surfaces of the retainer ring 200 and relatively moving along the X-axis while polishing is performed. Conceivable. However, in this method, since the wafer W and the retainer ring 200 rotate synchronously, a high surface accuracy (flatness) is required for the pressing surface 200a of the retainer ring 200 that presses the polishing surface of the polishing tool 8. If the flatness is low, the polishing accuracy of the wafer W will also decrease. On the other hand, in the present embodiment, since the protection member 91 is fixed and a relative rotation occurs between the protection member 91 and the wafer W, high processing accuracy is not required for the pressing surface 102, and processing cost can be reduced. it can.

In the above-described method using the retainer ring 200, the height of the pressing surface 200a of the retainer ring 200 with respect to the surface to be polished of the wafer W needs to be adjusted with high precision. For example, as shown in FIG. 18A, when the pressing surface 200a of the retainer ring 200 excessively protrudes from the surface to be polished of the wafer W, as shown in FIG. An insufficiently polished portion Y is generated at the outer peripheral end portion. Also, as shown in FIG. 19A, if the pressing surface 200a of the retainer ring 200 is too deep from the surface to be polished of the wafer W, FIG.
As shown in (b), the outer peripheral edge of the polished surface of the wafer W is excessively polished. On the other hand, in the present embodiment, the pressing surface 102 of the protection member 91 is pressed against the polishing surface of the polishing tool 8 with a constant pressure.
Since the height adjustment of the wafer W of No. 02 with respect to the surface to be polished is performed automatically, high assembly accuracy is not required, and the cost required for assembly can be reduced.

In the above-described method using the retainer ring 200, the effect of suppressing the excessive polishing generated at the outer peripheral end of the wafer W is reduced when the retainer ring 200 is worn. Even if the pressing surface 102 of the member 91 is worn, the height of the wafer W relative to the surface to be polished is automatically adjusted, so that the effect of suppressing excessive polishing can be stably obtained for a long time.

Further, according to the present embodiment, the protection member 9
1 is provided on the base BS in a rotation-restricted state, and the pressing surface 102 of the protection member 91 is pressed against the polishing surface of the polishing tool 8 with a constant pressure. Only one half of the generated wafer W can be selectively protected, and the structure can be simplified.

Further, according to the present embodiment, the polishing tool 8
Is polished to polish the wafer W, and the state of the effective working area of the polished surface with respect to the wafer W can be arbitrarily changed by the tilt angle, the polishing pressure, and the like. It is possible to limit the occurrence of the climbing portion to the wafer W to a very small part. That is, by adjusting the inclination angle, the polishing pressure, and the like of the polishing tool 8, when the polishing tool 8 is relatively moved in the X-axis direction with respect to the wafer W, the polishing tool 8 moves to the wafer W only immediately after the start of polishing. Ride occurs and the polishing tool 8
Can be eliminated with the progress of the relative movement with respect to the wafer W. Therefore, in the present embodiment, the pressing surface 102 of the protection member 91 is formed in a semi-annular shape surrounding one half of the outer periphery of the wafer W. However, by adjusting the inclination angle and the polishing pressure of the polishing tool 8, the protection member 91 can be appropriately adjusted. It can be miniaturized and its location can be selected. Also, the protection member 91
By reducing the size, the load on the control mechanism including the air cylinder can be reduced, accurate press control can be performed, and responsiveness in press control can be improved.
As a result, polishing with good uniformity becomes possible.

The present invention is not limited to the above embodiment. In the above-described embodiment, the protection member 91 has the support shafts 92 at both ends along the X-axis direction.
2 is rotatably supported by a column 93 erected on the upper surface of the base BS. Here, FIG.
FIG. 20 is a view showing another holding structure of the protection member 91. FIG.
, The protection member 91 is attached to a support 131 erected vertically on both sides of the protection member 91 on the base BS.
31 is provided so as to be movable through the piston rod 95 of each air cylinder 94 fixed to the base BS.
Are directly connected to the surface of the protection member 91 facing the base BS. As shown in FIG. 21, when the piston rod 95 of the air cylinder 94 is contracted, the pressing surface 102 of the protection member 91 remains parallel to the surface to be polished of the wafer W with the arrow Z1.
Descend in the direction of.

According to the holding structure shown in FIG. 20, the pressing surface 102 of the protection member 91 and the surface to be polished of the wafer W can always be kept parallel. So, for example,
The pressing surface 102 of the protection member 91 is the polishing surface 8a of the polishing tool 8.
And the contact state between the polishing surface 8a of the polishing tool 8 and the pressing surface 102 of the protection member 91 changes even if the height of the pressing surface 102 of the protection member 91 is adjusted accordingly. Never do.

In the embodiment described above, the guard portion 101 of the protection member 91 is integrally formed of, for example, a ceramic material, and the pressing surfaces 102 are all made of the same material. Here, FIG. 22A shows the pressing surface 1 of the protection member 91.
FIG. 22B is a plan view showing another configuration of the device No. 02, and FIG. 22B is a cross-sectional view taken along line GG of FIG. In FIG. 22, the pressing surface 102 of the protection member 91 includes a reinforcing portion 105 whose outer periphery is partially formed of a different material. For example, the guard portion 101 is formed of, for example, ceramics, the reinforcing portion 105 is resistant to abrasion, and the polishing surface 8 of the polishing tool 8 is formed.
It is formed of a material suitable for conditioning and dressing a.

With such a configuration, the polishing tool 8
The polishing surface 8a of the polishing member 8 protects the outer peripheral portion of the pressing surface 102 of the protection member 91, which is easily worn, so as to prolong the service life and to positively improve the conditioning and dressing effects for optimizing the polishing surface 8a of the polishing tool 8. Can be increased.

In the above-described embodiment, the protection member 9
The first pressing surface 102 is a smooth surface. However, in order to positively impart the conditioning effect and the dressing effect of the polishing surface 8a of the polishing tool 8 to the pressing surface 102 of the protection member 91, the pressing surface 102 is It is good also as a structure which makes an uneven surface suitable for conditioning and dressing.

The polishing apparatus 1 according to the embodiment described above
Described the case of the so-called partial polishing method in which the wafer W is held on the holding table 41, the polishing tool 8 is pressed against the wafer W, and the wafer W is partially brought into relative contact with each other, but the present invention is applied to another method. It is also applicable to the polishing apparatus of the above. For example, as shown in FIG. 23, the present invention is also applied to a polishing apparatus in which a polishing pad 401 having a polishing surface sufficiently larger than a wafer W is rotated, and a polishing target surface of the wafer W is pressed against the polishing pad 401 to perform polishing. It is possible.
When the surface to be polished of such a wafer W is in full contact with the surface of the polishing pad 401 as a polishing tool, for example, the periphery of the wafer W is surrounded by a cylindrical ring member 402 and the ring member The end face of 402 is pressed against the surface of polishing pad 401. Further, the wafer W is rotated in a predetermined direction, the ring member 402 is fixed, or rotated at a different rotation speed from the wafer W, and a relative rotation is generated between the ring member 402 and the wafer W to generate a wafer. Polishing of W is performed. With the above configuration,
Excessive polishing of the outer peripheral edge of the wafer W, which occurs in a polishing apparatus of a type in which the wafer W is entirely brought into contact with the polishing pad 401 and polished, can be suppressed.

[0083]

According to the present invention, excessive polishing of the outer peripheral edge of the surface to be polished of the object to be polished such as a semiconductor wafer can be suppressed. Further, according to the present invention, the state of the polished surface of the polishing tool can be optimized during the polishing process.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a view for explaining a rotating shaft tilting mechanism as a rotating shaft tilting means of the present invention.

FIG. 3 is a plan view showing a structure around a holding table of the polishing apparatus shown in FIG. 1;

FIG. 4 is a side view as seen from the direction of arrow J in FIG. 3;

FIG. 5 is a cross-sectional view taken along a line EE in FIG. 3;

FIG. 6 is a diagram for explaining the operation of the protection member.

FIG. 7 is a configuration diagram illustrating an example of a configuration of a control system of the air cylinder.

FIG. 8 is a diagram for explaining a method of controlling the pressing force of the air cylinder.

FIG. 9 is a view for explaining the polishing method of the present invention, and is a view showing a relative positional relationship between the wafer W and the polishing tool 8;

FIG. 10 is a view for explaining the polishing method of the present invention, and is a view showing an initial state of the polishing process.

FIG. 11 is a diagram showing a state in which polishing has progressed from the state shown in FIG. 10;

12A is a cross-sectional view illustrating a state in which the polishing tool runs in a riding area, and FIG. 12B is a cross-sectional view illustrating a state in which the polishing tool runs in a case where a protective member is not used.

FIG. 13 is a view for explaining the action of the protective member to remove foreign matter attached to the polishing tool.

FIG. 14 is a view for explaining an action of removing a deteriorated layer formed on the polishing tool by the protective member.

FIG. 15 is a view for explaining a dressing operation of the polishing surface of the polishing tool by the protective member.

FIG. 16 is a view for explaining an operation of adjusting a slurry permeation amount into a polishing tool by a protective member.

FIG. 17 is a plan view showing a state where a retainer ring is provided around a wafer.

FIG. 18 is a diagram for explaining a problem when the height of the retainer ring is too high.

FIG. 19 is a view for explaining a problem when the height of the retainer ring is too low.

FIG. 20 is a cross-sectional view showing another holding structure of the protection member.

FIG. 21 is a view for explaining the operation of the protection member.

FIG. 22 is a diagram showing another structure of the protection member.

FIG. 23 is a diagram showing another embodiment of the present invention.

FIG. 24 is a perspective view showing an example of a conventional polishing apparatus.

FIG. 25 is a view for explaining an example of a conventional polishing method.

FIG. 26 is a cross-sectional view showing elastic deformation at the outer peripheral edge of the wafer caused by pressing the polishing surface of the polishing tool against the wafer.

FIG. 27 is a plan view showing an excessively polished state of an outer peripheral end portion of a wafer W generated by elastic deformation of a polished surface of a polishing tool.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Polishing apparatus, 3 ... Column, 8 ... Polishing tool, 8a ... Polishing surface, 11 ... Z-axis moving mechanism, 20 ... Spindle holder, 2
DESCRIPTION OF SYMBOLS 1 ... Spindle spindle, 41 ... Rotary table, 51 ... X-axis moving mechanism, W ... Wafer, 91 ... Protective member, 101 ... Guard part, 102 ... Pressing surface.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tokuhisa Kawamura 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Kazuhiro Minami 1-10 Kiyohisa-cho, Kuki-shi, Saitama (72) Inventor Eiji Otani 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo F-term within Sony Corporation (reference) 3C058 AA09 AA12 AA19 AB04 AC01 AC04 AC05 BA07 BB04 CB01 CB03 DA17

Claims (58)

[Claims] 1. A polishing apparatus for polishing a polished surface by relatively moving a polished surface of a polished body and a polished surface of a polishing tool while pressing the polished surface of the polished object against the polished surface of the polishing tool. Having a pressing surface capable of being provided, and being provided on the outer periphery of the surface to be polished of the object to be polished so that relative movement occurs between the pressing surface and the surface to be polished of the object to be polished. A polishing apparatus comprising a protection member for suppressing excessive polishing of the outer peripheral end of the polished surface. 2. Pressing means for holding said protective member movably in a direction substantially perpendicular to a polishing surface of said polishing tool, and pressing a pressing surface of said protective member against a polishing surface of said polishing tool. The polishing apparatus according to claim 1, further comprising: 3. A gap between the inner peripheral edge of the pressing surface of the protective member and the outer peripheral edge of the polished surface of the polished body is predetermined so as to suppress excessive polishing of the outer peripheral end of the polished surface. The polishing apparatus according to claim 1, wherein the polishing apparatus is set to a value of: 4. The polishing apparatus according to claim 1, wherein the protection member is provided at a position separated by a predetermined gap from an outer periphery of the rotating object to be polished, in a state where rotation is regulated. 5. The polishing apparatus according to claim 1, wherein the pressing surface of the protection member is constituted by an annular surface or a part of the annular surface along the periphery of the polished surface of the polished body. 6. The polishing apparatus according to claim 1, wherein at least a pressing surface of said protection member is formed of a material harder than said polishing tool. 7. The polishing apparatus according to claim 6, wherein the polishing tool is formed of a material having a foamable resin material as a base material, and the protection member is formed of a ceramic material. 8. The pressing surface of the protective member removes foreign substances adhering to the polishing surface due to contact with the polishing surface of the polishing tool or an altered layer of the polishing surface, or dresses the polishing surface. Item 4. The polishing apparatus according to Item 1. 9. A holding table for rotatably holding an object to be polished, rotation holding means for rotatably holding the polishing tool, a surface to be polished of the object to be polished and a polishing surface of the rotating tool to be polished. Relative movement means for performing relative movement in the radial direction while pressing the polishing tool, comprising a pressing surface that can be pressed against the polishing surface of the polishing tool, and the surface to be polished of the object to be polished Protection that suppresses excessive polishing of the outer peripheral end of the polished surface provided so that relative movement occurs between the pressing surface and the polished surface of the polished object at a position separated from the outer periphery of the polished object A polishing apparatus comprising a member. 10. The polishing tool according to claim 1, wherein a rotation axis of said polishing tool is inclined at a predetermined angle in a direction perpendicular to a holding surface of said holding table toward a traveling direction of said polishing tool. The polishing apparatus according to claim 9, wherein the portion contacts a surface to be polished of the object to be polished. 11. The polishing apparatus according to claim 10, wherein said polishing tool has an annular polishing surface. 12. The polishing apparatus according to claim 9, further comprising abrasive supply means for supplying an abrasive to be interposed between a polishing surface of said polishing tool and a surface to be polished of said object to be polished. 13. A polishing apparatus for holding said protective member movably in a direction substantially perpendicular to a polishing surface of said polishing tool;
The polishing apparatus according to claim 9, further comprising a pressing unit configured to press a pressing surface of the protection member against a polishing surface of the polishing tool. 14. The pressing means comprises: holding means for rotatably holding the protection member about an axis parallel to a direction of relative movement between the polishing tool and the object to be polished; and holding the protection member with the axis. The polishing apparatus according to claim 9, further comprising a driving unit that rotates the center. 15. The drive means includes an air cylinder which incorporates a piston rod rotatably connected to the protection member and rotates the protection member about the axis by expansion and contraction of the piston rod. Item 15. A polishing apparatus according to Item 14. 16. A pressing force generated by said driving means is controlled in accordance with a distance between a contact position between said polishing surface and said pressing surface and said axis such that a pressure of said pressing surface against said polishing surface becomes constant. 15. A pressure control means for controlling the pressing force.
A polishing apparatus according to claim 1. 17. A guide means for movably guiding the protection member in a direction perpendicular to the polishing surface of the polishing tool, and a pressing means for directing the protection member in a direction perpendicular to the polishing surface of the polishing tool. The polishing apparatus according to claim 9, further comprising a driving unit for moving the polishing apparatus. 18. A polishing apparatus according to claim 17, wherein said driving means comprises an air cylinder. 19. A gap between the inner peripheral edge of the pressing surface of the protective member and the outer peripheral edge of the polished surface of the polished body is predetermined so that excessive polishing of the outer peripheral end of the polished surface can be suppressed. The polishing apparatus according to claim 9, wherein the polishing apparatus is set to a value of: 20. The pressing surface of the protective member abuts on the polishing surface at least before the polishing surface of the rotating polishing tool rides on the surface to be polished from the outside of the surface to be polished of the object to be polished. The polishing apparatus according to claim 9, wherein the polishing apparatus is provided so as to be capable of being provided. 21. The polishing apparatus according to claim 9, wherein the protection member is provided at a position separated from the outer periphery of the rotating object by a predetermined gap in a state where rotation is regulated. 22. The polishing apparatus according to claim 9, wherein the pressing surface of the protective member is formed by an annular surface or a part of the annular surface along the surface to be polished of the object to be polished. 23. A pressing surface of the protective member is arranged so as to surround one half of an outer periphery of a surface to be polished of the object to be polished along the direction of relative movement between the polishing tool and the object to be polished. 23. The polishing apparatus according to claim 22, wherein: 24. The polishing apparatus according to claim 9, wherein at least a pressing surface of said protective member is formed of a material harder than said polishing tool. 25. The polishing apparatus according to claim 24, wherein the polishing tool is formed of a material having a foamable resin material as a base material, and the protection member is formed of a ceramic material. 26. The polishing apparatus according to claim 9, wherein at least a part of the pressing surface of said protection member is formed of a material for dressing a polishing surface of said polishing tool. 27. The polishing apparatus according to claim 9, wherein at least a part of a pressing surface of said protective member is formed with irregularities for dressing a polishing surface of said polishing tool. 28. The pressing surface of the protective member removes foreign substances adhered to the polishing surface due to contact with the polishing surface of the polishing tool or a deteriorated layer of the polishing surface, or dresses the polishing surface. Item 10. A polishing apparatus according to Item 9. 29. A pressing surface of the protective member substantially presses a polishing surface of the polishing tool at an inner peripheral portion on the side of the object to be polished,
29. The polishing apparatus according to claim 28, which removes foreign matters adhering to the polishing surface substantially at an outer peripheral portion or a deteriorated layer of the polishing surface, or dresses the polishing surface. 30. A polishing method for polishing the surface to be polished by pressing the surface to be polished of the object to be polished and the surface to be polished of the polishing tool relative to each other while pressing them against each other. A protection member having a pressing surface capable of being provided is provided on the outer periphery of the surface to be polished of the object to be polished, and the pressing surface of the protection member is pressed against the polishing surface of the polishing tool with a predetermined pressing force. A relative movement is generated between the surface to be polished of the object to be polished and the surface to be polished of the polishing tool, the surface to be polished of the object to be polished, and the pressing surface of the protective member. A polishing method for polishing a polishing surface. 31. A holding member for movably holding the protection member in a direction substantially perpendicular to a polishing surface of the polishing tool;
The polishing method according to claim 30, wherein a pressing surface of the protection member is pressed against a polishing surface of the polishing tool. 32. A gap between an inner peripheral edge of the pressing surface of the protective member and an outer peripheral edge of the surface to be polished of the object to be polished is set so as to suppress excessive polishing of the outer peripheral end of the surface to be polished. The polishing method according to claim 30, wherein the value is set to a value. 33. The polishing method according to claim 30, wherein the protection member is provided at a position separated by a predetermined gap from the outer periphery of the rotating object to be polished in a state where rotation is regulated. 34. The polishing method according to claim 30, wherein the pressing surface is constituted by an annular surface or a part of an annular surface along the periphery of the surface to be polished of the object to be polished is used as the protective member. 35. The polishing method according to claim 30, wherein at least the pressing surface is formed of a material harder than the polishing tool. 36. The polishing tool according to claim 35, wherein the polishing tool is formed of a material having a foamable resin material as a base material, and the protection member is formed of a ceramic material. The polishing method as described above. 37. Removal of foreign matter adhered to the polishing surface or a deteriorated layer of the polishing surface due to contact between the pressing surface of the protective member and the polishing surface of the polishing tool, or dressing of the polishing surface. 30. The polishing method according to 30. 38. A holding table for rotatably holding an object to be polished, rotation holding means for rotatably holding the polishing tool, a surface to be polished of the object to be polished and a polishing surface of the rotating tool to be polished. Relative movement means for making relative movement in the radial direction while pressing the polishing tool, wherein a protective member having a pressing surface capable of contacting and pressing the polishing surface of the polishing tool is provided on the object to be polished. Provided so that relative movement occurs between the pressing surface and the surface to be polished of the object to be polished at a position separated from the outer periphery of the surface to be polished, thereby suppressing excessive polishing of the outer peripheral end of the surface to be polished. Polishing method. 39. A rotating shaft of the polishing tool is inclined at a predetermined angle toward a traveling direction of the polishing tool with respect to a direction perpendicular to a holding surface of the holding table, and a part of the polishing surface of the polishing tool is changed. 4. The method according to claim 3, wherein the polishing target is brought into contact with a surface to be polished.
9. The polishing method according to item 8. 40. The polishing method according to claim 38, wherein the polishing tool has an annular polishing surface. 41. The polishing method according to claim 38, wherein the polishing is performed by interposing an abrasive between the polishing surface of the polishing tool and the surface to be polished of the object to be polished. 42. The protection member is movably held in a direction substantially perpendicular to a polishing surface of the polishing tool, and
The polishing method according to claim 38, wherein the polishing is performed by pressing a pressing surface of the protective member against a polishing surface of the polishing tool. 43. Polishing by holding the protective member rotatably about an axis parallel to the direction of relative movement between the polishing tool and the object to be polished, and rotating the protective member about the axis. 39. The polishing method according to claim 38. 44. A piston rod rotatably connected to the protection member, and a pressing surface of the protection member is formed using an air cylinder that rotates the protection member about the axis by expansion and contraction of the piston rod. 43. The polishing method according to claim 42, wherein the polishing method is pressed against a polishing surface of the polishing tool. 45. The method according to claim 42, wherein said pressing force is controlled in accordance with a distance between a contact position between said polishing surface and said pressing surface and said axis such that a pressure of said pressing surface against said polishing surface becomes constant. The polishing method as described above. 46. Polishing is performed by movably guiding the protective member in a direction perpendicular to the polishing surface of the polishing tool, and by directly moving the protective member in a direction perpendicular to the polishing surface of the polishing tool. A polishing method according to claim 38. 47. The polishing method according to claim 46, wherein the protective member is linearly moved using an air cylinder. 48. A gap between the inner peripheral edge of the pressing surface of the protective member and the outer peripheral edge of the surface to be polished of the object to be polished is set so as to suppress excessive polishing of the outer peripheral end of the surface to be polished. 39. The polishing method according to claim 38, wherein the value is set to: 49. The pressing surface of the protective member is brought into contact with the polishing surface at a position at least before the polishing surface of the rotating polishing tool rides on the polishing surface from outside the polishing surface of the polishing object. 39. The polishing method according to claim 38, wherein the polishing is performed by being provided as possible. 50. The polishing method according to claim 38, wherein the protection member is provided at a position separated by a predetermined gap from an outer periphery of the rotating object to be polished in a state where rotation is regulated. 51. The polishing method according to claim 38, wherein the pressing surface of the protective member is formed of an annular surface or a part of the annular surface along the surface to be polished of the object to be polished. 52. A pressing surface of the protective member is arranged so as to surround one half of an outer periphery of a surface to be polished of the object to be polished along the direction of relative movement between the polishing tool and the object to be polished. The polishing method according to 51. 53. The polishing method according to claim 38, wherein at least a pressing surface of said protective member is formed of a material harder than said polishing tool. 54. The polishing tool according to claim 53, wherein the polishing tool is made of a material having a foamable resin material as a base material, and the protection member is made of a ceramic material. Polishing method. 55. The polishing method according to claim 38, wherein at least a part of a pressing surface of said protective member is formed of a material for dressing a polishing surface of said polishing tool. 56. The polishing method according to claim 38, wherein at least a part of a pressing surface of said protective member is provided with irregularities for dressing a polishing surface of said polishing tool. 57. Removal of foreign matter adhering to the polishing surface or an altered layer of the polishing surface due to contact between the pressing surface of the protective member and the polishing surface of the polishing tool, or dressing of the polishing surface. 39. The polishing method according to claim 38. 58. The pressing surface of the protective member substantially presses the polishing surface of the polishing tool at the inner peripheral portion on the side of the object to be polished, and substantially adheres foreign matter or foreign matter adhering to the polishing surface at the outer peripheral edge portion. 58. The polishing method according to claim 57, wherein the altered layer on the polished surface is removed or the polished surface is dressed.