WO2003064108A1

WO2003064108A1 - Polishing head, polishing device and polishing method

Info

Publication number: WO2003064108A1
Application number: PCT/JP2002/000777
Authority: WO
Inventors: Yasuyuki Ogata; Manabu Kanemoto; Hiroyuki Kobayashi
Original assignee: Mitsubishi Materials Corporation
Priority date: 2002-01-28
Filing date: 2002-01-31
Publication date: 2003-08-07
Also published as: TW523443B

Abstract

A polishing head (61) comprising a disc-like carrier (16) for holding at the lower surface thereof one surface of a wafer (W), and an annular retainer ring (17) disposed concentrically with, and on the outer periphery of, the carrier (16), held at the inner peripheral surface (17a) thereof by the carrier (16) while in contact with a polishing pad (4) at polishing, and locking the outer periphery of the wafer (W). The carrier (16) is formed with a flow passage (62) for supplying slurry or a cleaning liquid into a clearance (K) between an outer peripheral surface (16a) and the inner peripheral surface (17a) of the retainer ring (17). The flow passage (62) is connected with a slurry/cleaning liquid supply mechanism (31) for selectively supplying either slurry or a cleaning liquid to the passage (62).

Description

PC orchid 2/00777

1

Description Polishing head, polishing apparatus and polishing method

The present invention relates to a silicon wafer (bare wafer) of virgin or silicon on the surface.

■ Silicon wafer with germanium layer (SiGe layer) formed, semiconductor in semiconductor manufacturing process: c-ha, or hard disk substrate, liquid crystal substrate, optical component lens, etc. (hereinafter referred to as wafer W) The present invention relates to a polishing head and a polishing apparatus applied to a device for polishing a surface of a workpiece having a flat surface, and a method for polishing a workpiece using the same. Background art

In recent years, the pattern miniaturization has been progressing along with the high integration of semiconductor manufacturing equipment. In particular, since a fine pattern of a multilayer structure can be easily and surely formed, a semiconductor pattern during a manufacturing process is required. It is important to flatten the surface of the eight as much as possible

. For example, the pattern is formed using optical lithography, but as the pattern becomes finer, the depth of focus of optical lithography decreases. In order to ensure pattern accuracy and facilitate focus adjustment during exposure, it is necessary to make the difference in unevenness on the surface of the wafer less than the depth of focus (flatten). Required. Also in the polishing of Berue 18, ゥ: 要求 With the increase in the diameter of 18, the demand for flattening is becoming stricter (here, the case of ゥ was described as an example, but these ゥ: Polishing of materials to be polished other than L-ha, such as hard disk substrates and liquid crystal substrates, also requires highly accurate flattening of the surface.) The chemical mechanical polishing method (CMP method) has been spotlighted from the viewpoint that the film on the surface can be flattened with high precision and the film can be embedded in the concave portion on the wafer surface.

The CMP method, was used S i 0 ₂ alkaline slurry and C e 0 ₂ neutral slurry with using or acidic slurry with AI ₂ 0 _3,, the abrasive agent slurry This is a method of chemically and mechanically polishing and flattening the wafer surface using a first-class method. As an apparatus for polishing the surface of a wafer by using the CMP method, for example, a polishing apparatus as shown in an enlarged perspective view of a main part in FIG. 15 is known.

As schematically shown in FIG. 15, the polishing apparatus 1 is provided with a polishing pad 4 made of, for example, hard urethane on a disk-shaped platen 3 attached to a center shaft 2. In addition, a polishing head 5 that is rotationally driven by a head driving mechanism (not shown) is disposed at a position eccentric from the center axis 2 of the platen 3.

Although not shown, the polishing head 5 has a disc-shaped carrier that holds one surface of the wafer W on the lower surface, and an annular relining that is arranged concentrically around the outer periphery of the carrier. The retainer ring comes into contact with the polishing pad 4 at the time of polishing. The inner surface of the retainer ring holds the outer periphery of the wafer W held by the carrier, and the lower surface of the polishing pad 4 presses the wafer W to polish the wafer W. The deformation of the polishing pad 4 in the vicinity of the outer periphery of the wafer is suppressed, and the polishing accuracy of wafer W is ensured.

In the polishing apparatus 1, the slurry S described above is supplied to the vicinity of the rotation center C of the polishing pad 4 when polishing the wafer W. The slurry S spreads toward the outer peripheral side in the radial direction on the polishing pad 4 by flowing on the polishing pad 4 and receiving a centrifugal force generated by the rotation of the polishing pad 4, and Flow between the polishing pad 4 and the wafer W held by the pad 5. In this state, the wafer W was held by the polishing head 5: The wafer L was rotated on its own axis, and at the same time, the polishing pad 4 was rotated about the central axis 2 so that one surface of the wafer W was polished by the polishing pad 4. .

In such a polishing apparatus 1, first, in order to adjust the surface condition of the polishing pad 4, a work (dressing) of slightly polishing the surface of the polishing pad 4 is performed. Supplied above. Thereafter, the wafer W is polished using the slurry S (the polishing of the wafer W and the dressing may be performed in parallel), but after the polishing, pure water is supplied to the surface of the polishing pad 4. Then, wafer W is polished using this pure water instead of slurry S. As a result, the surface of wafer W is cleaned (rinse polishing). With these as one cycle, polishing of new ゥ:!: Haha W is performed one after another. In the case where polishing is performed on the polishing pad A / W after the dressing or the previous polishing is performed, the slurry S is supplied onto the polishing pad 4 and the slurry S flows on the polishing pad 4. The polishing was performed while flushing the liquid such as pure water remaining in the wafer. However, since it takes time for the slurry S to sufficiently spread on the polishing pad 4, the slurry S is diluted by the liquid remaining on the polishing pad 4 in the initial stage of polishing. Therefore, the wafer W is polished in a state where there is a difference in the slurry concentration in each part of the polishing pad 4. Also, the slurry S may flow out of the retainer due to the centrifugal force generated by the rotation of the platen 3, or may not reach the surface of the wafer sufficiently, where the retainer ring acts as a barrier and is retained on the inner peripheral side of the retainer ring.ゥ In some cases, the center part of Eha W was difficult to be polished. For this reason, the polishing efficiency of the wafer W decreases.

Therefore, when the liquid on the polishing pad 4 is swept away by the flow of the slurry S supplied on the polishing pad 4 to replace the liquid on the polishing pad 4 with the slurry S, and then the wafer W is polished. However, it is necessary to supply a large amount of the slurry S onto the polishing pad 4 before the polishing, and the consumption of the expensive slurry S increases. For example, in the case of device polishing, the cost of slurry S accounts for about 70% of the consumable material cost of the polishing equipment, so it is important to reduce the amount of slurry consumed to reduce consumable material cost. Is

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a polishing head capable of satisfactorily polishing an wafer. Another object of the present invention is to provide a polishing apparatus capable of reducing the consumption of slurry and a method for polishing a workpiece using the polishing apparatus. Disclosure of the invention

In order to solve the above-described problems, a first aspect of the present invention is to provide a method for pressing a material to be polished against a surface of a polishing pad stuck on a platen while moving relatively to the polishing pad. A polishing head for polishing an abrasive material, a carrier holding one surface of a material to be polished on its lower surface, and a concentrically arranged outer peripheral side of the carrier; While being in contact with the pad, T / JP02 / 00777

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An annular retainer ring that locks an outer periphery of the workpiece to be polished, and a liquid supply path for supplying liquid to a gap between an outer peripheral surface of the carrier and an inner peripheral surface of the retainer ring. A polished head characterized by being formed.

In the polishing head configured as described above, when polishing the material to be polished, the liquid passes through the liquid supply passage, and the gap between the outer peripheral surface of the carrier holding one surface of the material to be polished and the inner peripheral surface of the retaining ring, That is, since the liquid is supplied to the gap located on the outer periphery of the material to be polished, the liquid is directly supplied between the material to be polished and the polishing pad without being hindered by the rotation / retainer ring of the platen.

Thus, a sufficient amount of liquid can be supplied between the workpiece and the polishing pad. In addition, the liquid supplied between the workpiece and the polishing pad is surrounded by the relining, and the outer periphery of the retainer ring is affected by the centrifugal force caused by the rotation of the polishing head and the platen. Since the liquid does not easily flow out, the liquid can be used efficiently, and for example, the amount of expensive slurry used can be reduced.

Here, in the polishing head, the carrier is heated by receiving the processing heat generated during polishing of the material to be polished. When the carrier is thermally deformed, the deformation affects the material to be polished held by the carrier. Polishing accuracy of the workpiece is reduced. In the polishing head according to this aspect, since the carrier is cooled by the liquid passing through the liquid supply passage, the thermal deformation of the carrier can be reduced, and the polishing accuracy of the workpiece can be improved.

Further, the liquid supply path may be at least one of a flow path A provided in the carrier and a flow path B provided in the retainer ring.

When both the flow path A and the flow path B are provided, the slurry can be supplied between the workpiece and the polishing pad from two locations, so that the slurry supply amount can be increased.

Further, the liquid supply path may be connected to a slurry cleaning liquid supply mechanism for selectively supplying one of a slurry and a cleaning liquid.

In particular, the slurry tends to gradually clog in the gaps between the polishing heads as it gradually dries or deteriorates, and if such slurry falls on the polishing pad, it may cause scratches on the surface of the workpiece. In the polishing head according to this aspect, the polishing operation is completed. At an appropriate time, such as when the slurry is supplied, the supply of the slurry from the slurry cleaning liquid supply mechanism to the liquid supply path is stopped, and the cleaning liquid is supplied into the liquid supply path instead. The slurry remaining in the gap between the outer peripheral surface and the inner peripheral surface of the retainer ring can be washed away with the cleaning liquid. As the cleaning liquid, for example, pure water, a solvent constituting a slurry, or the like may be used.

Further, a groove A connected to the flow path A and supplied with the liquid from the flow path A may be formed on the entire outer circumference of the carrier.

Further, a groove B connected to the flow path B and supplied with the liquid from the flow path B may be formed on the entire circumference of the inner peripheral surface of the retainer ring.

If the slurry is locally supplied between the polishing material and the polishing pad, polishing of the polishing material partially proceeds in that portion. However, when the flow path A is formed in the carrier as described above, by providing the carrier with the groove A, the slurry supplied to the outer peripheral surface of the carrier by the flow path A can be completely removed by the groove A. It is guided to the circumference and flows down from the entire circumference of the outer peripheral surface. Similarly, when the flow path B is provided in the retainer ring, the groove B is provided in the retainer ring, so that the slurry supplied to the inner peripheral surface of the retainer ring by the flow path B has an inner circumferential surface formed by the groove B. It is guided along the entire circumference of the surface and flows down from the entire circumference of the inner peripheral surface. As a result, the slurry is almost uniformly supplied between the polishing material and the polishing pad from the entire outer circumference of the polishing material, and the polishing amount is made substantially uniform over the entire surface of the polishing material. be able to.

Also, the supply of the slurry to the flow path and the slurry B from the slurry cleaning liquid supply mechanism is stopped, and the cleaning liquid is supplied to the flow path and the B instead. The cleaning liquid can be spread over the entire circumferential range of the gap formed therebetween, and the remaining slurry can be more effectively washed away.

Further, the flow path A may be communicated from the center of the upper surface of the carrier to a plurality of locations on the outer peripheral surface, and may be formed substantially radially from the center to the outer peripheral side.

The slurry can be supplied almost uniformly to the outer periphery of the carrier, and the flow path A is formed in the entire carrier, so that the slurry passing through the flow path A cools the carrier more effectively. Also, when polishing the material to be polished, the slurry supplied into the flow path A is sent out to the outer peripheral surface by centrifugal force generated by the rotation of the polishing head. Therefore, the slurry can be smoothly supplied to the outer peripheral surface of the carrier. Further, the liquid supply path may be formed in an annular shape and have a diameter of 2 mm or more and 1 O mm or less.

If the diameter of the annular liquid supply path is smaller than 2 mm, the slurry tends to be clogged, and if it is larger than 1 Omm, the strength of the carrier and the retainer ring that form the liquid supply path decreases. 2 mm or more and 1 O mm or less are desirable.

Further, an elastic body is provided in the gap between the outer peripheral surface of the carrier and the inner peripheral surface of the retainer ring to allow relative displacement in the up-down direction and connected, and a liquid is supplied to the elastic body in the gap. A supply port for supplying the liquid may be provided, and the liquid supply path may be connected to the supply port.

In the polishing head configured as described above, a carrier that holds one surface of the material to be polished and a retainer ring that locks the outer periphery of the material to be polished are connected via an elastic body. Then, the slurry supplied from the liquid supply passage is supplied to the gap between the outer peripheral surface of the carrier and the inner peripheral surface of the retainer ring through a supply port provided in the elastic body, whereby the rotation of the platen and the retainer ring are performed. The slurry is directly supplied between the workpiece and the polishing pad from the gap without being hindered, and a sufficient amount of slurry can be supplied between the workpiece and the polishing pad.

Also, the slurry supplied between the workpiece and the polishing pad is surrounded by a retainer ring, and flows out to the outer periphery of the retainer ring even when subjected to centrifugal force due to the rotation of the polishing head and the platen. It is difficult to use the slurry efficiently.

Here, the slurry is liable to be clogged in the gap between the polishing heads as it gradually dries, changes in quality, and solidifies with the passage of time, and if such slurry falls into a lump on the polishing pad, it is polished. This causes scratches on the surface of the material. Therefore, a slurry Z cleaning liquid supply mechanism for selectively supplying either the slurry or the cleaning liquid may be provided in the liquid supply path connected to the supply port.

With this configuration, the slurry is supplied to the supply port by the slurry cleaning liquid supply mechanism during polishing. At the appropriate time, such as when the polishing work is completed, the supply of the slurry from the slurry cleaning liquid supply mechanism to the supply port is stopped, and the cleaning liquid is supplied to the supply port instead. The slurry remaining in the gap between the outer peripheral surface of the carrier and the inner peripheral surface of the retainer ring can be washed away by the cleaning liquid. As the cleaning liquid, for example, pure water, a solvent constituting a slurry, or the like may be used.

Here, in the polishing head, the retainer ring locks the outer periphery of the polishing target material held by the carrier and suppresses deformation of the polishing pad near the outer periphery of the polishing target material. It is desirable that the gap formed between the retainer ring and the inner peripheral surface be as small as possible. However, when the gap is reduced in this manner, the area of the elastic body exposed in the gap is also reduced, and the size of the supply port is limited, so that the supply amount of the slurry or the cleaning liquid from the supply port is reduced. I will.

Therefore, at least one of an outer peripheral edge of the carrier and an inner peripheral edge of the retainer ring is provided at a portion facing the elastic body with a housing portion that forms a housing space between the other peripheral edge portion and the elastic body. Then, the supply roller may be provided at a portion facing the storage space.

In this configuration, at least one of the outer peripheral edge of the carrier and the inner peripheral edge of the retainer ring faces the elastic body, and a housing portion that forms a housing space is formed. Since the elastic body is exposed not only in the gap but also in the accommodation space, the gap formed between the outer peripheral surface of the carrier and the inner peripheral surface of the reanna ring is reduced, and the supply port is formed in the elastic body. It is possible to secure an area in which it can be provided.

Here, if the slurry is locally supplied between the polishing target and the polishing pad, polishing of the polishing target partially proceeds at that portion.

Therefore, the housing portion may be provided over the entire periphery of the peripheral portion where the housing portion is provided.

In this configuration, the slurry supplied from the supply port into the storage space is guided by the storage section along the circumferential direction of the peripheral portion where the storage section is provided, and flows down from the entire circumference.

As a result, a slurry is formed between the polishing material and the polishing pad from the entire outer circumference of the polishing material. T / JP02 / 00777

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The resin is supplied almost uniformly, and the polishing amount can be made substantially uniform over the entire surface of the material to be polished.

When the polishing head is provided with a slurry cleaning liquid supply mechanism, by supplying the cleaning liquid to the supply port, a circumferential direction of a gap formed between the outer peripheral surface of the carrier and the inner peripheral surface of the retainer ring is provided. The washing liquid can be spread over the entire area of the gap, and the slurry remaining in the gap can be more effectively washed away.

A wall portion that stands upright in a gap between a lower surface of the housing portion and a peripheral surface of a peripheral portion provided with the housing portion; and a plurality of circumferential portions of the wall portion; And a connection path connecting the peripheral surface and the peripheral surface.

In this configuration, the slurry or the cleaning liquid supplied into the storage space is once received by the wall and flows along the wall in the circumferential direction of the storage space. Then, when the slurry or the cleaning liquid reaches the connection passages provided at various places in the circumferential direction of the wall portion, the slurry or the cleaning liquid flows out into the gap formed between the carrier and the retainer ring through the connection passage. That is, the slurry or the cleaning liquid supplied into the housing space flows out into the gap through the connection path at various points in the circumferential direction of the head body, so that the slurry or the cleaning liquid can be supplied more uniformly over the entire circumference of the gap. it can.

Further, an inclined surface may be provided on the lower surface of the housing portion so as to be gradually inclined downward toward the peripheral surface.

With this configuration, the slurry supplied into the storage space flows quickly toward the gap along the inclined surface provided on the lower surface of the storage portion, so that the slurry is less likely to stay and the slurry is Drying, deterioration, and solidification can be suppressed. In a second aspect of the present invention, a material to be polished is pressed against a surface of a polishing pad stuck on a platen while being relatively moved with respect to the polishing pad by a polishing head. A polishing method for polishing an abrasive material, wherein the polishing head is used to supply slurry from the liquid supply path to a gap between an outer peripheral surface of the carrier and an inner peripheral surface of the reanna ring. This is a polishing method for polishing a material to be polished.

In the polishing head configured as described above, when polishing the material to be polished, the slurry supplied from the slurry / cleaning liquid supply mechanism passes through the liquid supply path to the outer peripheral surface of the carrier that holds one surface of the material to be polished, and Retainer ring that locks the outer periphery of the abrasive 02 00777

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The slurry is directly supplied to the polishing pad without being hindered by the rotation of the platen or the retainer ring. Supplied.

Thereby, a sufficient amount of slurry can be supplied between the material to be polished and the polishing pad. In addition, the slurry supplied between the workpiece and the polishing pad is surrounded by the retainer ring, so that the slurry remains on the outer periphery of the retainer ring even when subjected to centrifugal force due to the rotation of the polishing head and the platen. Since it does not easily flow out, the slurry can be used efficiently, and the amount of expensive slurry used can be reduced. Here, in the polishing head, the carrier is heated by receiving the processing heat generated during polishing of the material to be polished. When the carrier is thermally deformed, the deformation affects the material to be polished held by the carrier. Polishing accuracy of the workpiece is reduced. In the polishing head according to the present invention, since the carrier is cooled by the slurry passing through the liquid supply path, the thermal deformation of the carrier can be reduced, and the polishing accuracy of the workpiece can be improved.

Further, the slurry is liable to be clogged in the gap between the polishing heads as it gradually dries or deteriorates, and if such a slurry falls on the polishing pad, it causes a scratch on the surface of the material to be polished. In the polishing head according to the present invention, the supply of the slurry from the slurry cleaning liquid supply mechanism to the liquid supply path is stopped at an appropriate time such as when the polishing operation is completed, and the cleaning liquid is supplied into the liquid supply path instead. Thus, the slurry remaining in the liquid supply path and in the gap between the outer peripheral surface of the carrier and the inner peripheral surface of the retainer ring can be washed away with the cleaning liquid. As the cleaning liquid, for example, pure water, a solvent constituting a slurry, or the like may be used.

In a third aspect of the present invention, the polishing target is pressed against a surface of a polishing pad stuck on a platen while being moved relatively to the polishing pad by a polishing head. A polishing apparatus for polishing a material, the apparatus including a spraying apparatus for blowing at least one of a gas and a slurry onto a surface of the polishing pad. In the polishing apparatus configured as described above, at least one of gas and slurry is sprayed on the surface of the polishing pad by the spraying apparatus.

If the spray device is configured to blow gas, a liquid such as pure water may be applied on the polishing pad. In the remaining state, a gas is blown onto the surface of the polishing pad by a spraying device, whereby the liquid on the polishing pad is swept away by the gas and removed.

Further, when the spraying device is configured to spray the slurry, the liquid on the polishing pad is swept away by the slurry sprayed on the surface of the polishing pad by the spraying device, and the liquid is replaced with the slurry.

When the spraying device is configured to spray both gas and slurry to the polishing pad, first, gas is blown to the surface of the polishing pad to remove the liquid on the polishing pad, and then to the surface of the polishing pad. By spraying the slurry, a layer of the slurry not diluted by the liquid is formed on the polishing pad.

Here, the spraying device may have a nozzle for discharging gas or slurry, and a nozzle moving mechanism for moving the nozzle on the surface of the polishing pad.

In this case, while the gas or slurry is discharged from the nozzle and sprayed onto the surface of the polishing pad, the nozzle or moving mechanism moves the nozzle relative to the surface of the polishing pad, so that the gas or slurry is discharged from the surface of the polishing pad. Sprayed evenly.

Here, it is sufficient that the gas or the slurry can be sprayed on at least the entire region used for polishing the workpiece on the surface of the polishing pad.

The nozzle moving mechanism can be configured to move the nozzle, for example, from a position facing the rotation center of the polishing pad toward the radially outer peripheral side.

In this configuration, the platen is driven to rotate the polishing pad, and in parallel with this, while blowing gas or slurry from the nozzle to the polishing pad, the nozzle is moved radially outward from a position facing the rotation center of the polishing pad. By moving the polishing pad toward the outer periphery in the radial direction from the rotation center of the polishing pad, the gas or slurry is sprayed in a spiral shape, and the gas or slurry is evenly sprayed on the surface of the polishing pad. May be connected to a cleaning liquid supply source for supplying a cleaning liquid. The slurry dries or deteriorates over time and solidifies, so if the spraying device is configured to discharge the slurry from the nozzle, the cleaning liquid supply source is connected to the nozzle in this way, and the Supplying the cleaning liquid from the cleaning liquid supply source to the nozzle Thus, the slurry in the nozzle is washed away by the cleaning liquid, and the nozzle can be prevented from being clogged.

Further, by supplying the cleaning liquid onto the polishing pad from the nozzle, the polishing pad can be cleaned.

Further, the above-mentioned polishing apparatus may be used in combination with the above-mentioned polishing head. A fourth embodiment of the present invention is a method for polishing a material to be polished, which is performed using the polishing apparatus, wherein a gas or slurry is sprayed on a surface of the polishing pad by the spraying device, and the surface of the polishing pad is A polishing method for a material to be polished, characterized in that after the liquid is removed, the slurry is supplied onto the polishing pad to polish the material to be polished.

When the spraying device is configured to blow gas, the gas such as pure water is left on the polishing pad, and the gas is blown onto the surface of the polishing pad by the spraying device so that the gas blows on the polishing pad. The liquid is swept away and removed.

When the spraying device is configured to blow both gas and slurry onto the polishing pad, first, gas is blown onto the surface of the polishing pad to remove the liquid on the polishing pad, and then the surface of the polishing pad is removed. By spraying the slurry on the polishing pad, a layer of the slurry not diluted by the liquid is formed on the polishing pad. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a longitudinal sectional view showing a configuration of a polishing head according to the first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view illustrating a schematic configuration of a main part of the polishing head according to the first embodiment.

FIG. 3A is a longitudinal sectional view showing another example of the configuration of the polishing head according to the first embodiment.

FIG. 3B is a longitudinal sectional view showing another example of the configuration of the polishing head according to the first embodiment. FIG.

FIG. 4 is a longitudinal sectional view showing a configuration of a polishing head according to the second embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing a configuration of a polishing head according to the third embodiment of the present invention.

FIG. 6A is a longitudinal sectional view showing an example of the configuration of a polishing head according to the third embodiment of the present invention.

FIG. 6B is a longitudinal sectional view showing an example of the configuration of the polishing head according to the third embodiment of the present invention.

FIG. 6C is a longitudinal sectional view showing an example of the configuration of the polishing head according to the third embodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing a configuration of a polishing head according to a fourth embodiment of the present invention.

FIG. 8 is a longitudinal sectional view showing a configuration of a polishing head according to a fifth embodiment of the present invention.

FIG. 9 is a tip view of a polishing head according to a fifth embodiment of the present invention. FIG. 10 is a partially enlarged view schematically showing a main part of a polishing head according to a fifth embodiment of the present invention.

FIG. 11 is a longitudinal sectional view showing the configuration of another polishing head according to the fifth embodiment of the present invention.

FIG. 12 is a perspective view showing a configuration of a polishing apparatus according to one embodiment of the present invention. FIG. 13 is a longitudinal sectional view showing a configuration of a polishing apparatus according to another embodiment of the present invention.

FIG. 14 is a graph showing the polishing performance of the material to be polished in the polishing apparatus according to the present invention when the spraying apparatus is used and when it is not used. FIG. 15 is a perspective view schematically showing a conventional polishing apparatus. BEST MODE FOR CARRYING OUT THE INVENTION

First embodiment Hereinafter, a polishing head according to an embodiment of the present invention will be described with reference to the drawings. Here, FIGS. 1 and 2 are views showing the configuration of the polishing head according to the present embodiment, FIG. 1 is a vertical cross-sectional view, and FIG. 2 is a vertical cross-sectional view showing a schematic configuration of a main part. . The polishing head according to the present embodiment is used in place of the polishing head 5 in, for example, the conventional polishing apparatus shown in FIG.

As shown in FIG. 1, the polishing head 11 according to the present embodiment includes a head main body 12 including a top plate 13 and a peripheral wall portion 14 formed in a cylindrical shape, and a head main body. 12 and a diaphragm 15 (elastic body) stretched inside.

On the lower surface of the diaphragm 15, a disc-shaped carrier 16 that holds one surface of the wafer W (a material to be polished) by the lower surface, and between the inner wall of the peripheral wall portion 14 and the outer peripheral surface 16 a of the carrier 16. It is provided concentrically, and is fixed to an annular retainer ring 17 that locks the outer periphery of the wafer W held by the carrier 16 on the inner peripheral surface 17a while being in contact with the polishing pad 4 during polishing. I have.

The carrier 16 and the retainer ring 17 are connected via a diaphragm 15 while allowing relative displacement in the vertical direction with respect to each other.

The head body 1 2 is composed of a disk-shaped top plate 13 and a cylindrical peripheral wall 14 fixed below the outer periphery of the top plate 13, and the lower end of the head body 1 2 The part is open and hollow. The top plate 13 is coaxially fixed to a shaft 19 connected to the main body of the polishing apparatus. The shaft 19 has a first flow hole 20 connected to a pressure adjusting mechanism 30 described later. a and a second flow hole 20b connected to the slurry / washing liquid supply mechanism 31 are formed parallel to the axis. At the lower end of the peripheral wall portion 14, a step portion 14a is formed over the entire circumference.

The carrier 16 made of a high-rigidity material such as ceramics is formed in a substantially disc-like shape with a constant thickness, and the diaphragm 15 is interposed between the carrier fixing ring 21 provided on the upper surface of the diaphragm 15. It is attached to the diaphragm 15 by being fixed in a sandwiched state.

The retainer ring 17 is formed in a substantially annular shape as shown in FIG. 1 and has a slight gap between the retainer ring 17 and the inner wall of the peripheral wall portion 14 and the outer peripheral surface 16 a of the carrier 16. They are arranged concentrically with these. Where carrier 16 and retainer 777

14

The gap formed between the connector 17 and K is indicated by the symbol K (see FIG. 2). The retainer ring 17 is attached to the diaphragm 15 by being fixed to the retainer ring fixing ring 22 provided on the upper surface of the diaphragm 15 with the diaphragm 15 interposed therebetween. ing.

At least one of the outer peripheral edge of the carrier 16 and the inner peripheral edge of the retainer ring 17 has an accommodation space C at a portion facing the diaphragm 15 and between the other peripheral edge. An accommodating portion 23 is provided. In the present embodiment, a notch is provided in the outer peripheral edge of the carrier 16 to form the accommodation portion 23, and the accommodation portion

23 is provided over the entire outer peripheral edge of the carrier 16.

The diaphragm 15 made of an elastic material such as fiber reinforced rubber is formed in an annular or disk shape, and its outer peripheral edge is formed by a step 14 a and a step 14 formed on the inner wall of the peripheral wall 14. It is fixed to the head body 12 by being sandwiched between the diaphragm fixing ring 26 attached to a.

Above the diaphragm 15, a fluid chamber 27 is formed between the diaphragm 15 and the head body 12. The fluid chamber 27 is connected to the pressure adjusting mechanism 30 through a first flow hole 20 a formed in the shaft 19. And, inside the fluid chamber 27, a pressure adjusting mechanism

The pressure in the fluid chamber 27 is adjusted by supplying a fluid such as air from 30 through the first circulation hole 20a.

Further, the diaphragm 15 is provided with a supply port 28 for supplying slurry into a gap K formed between the outer peripheral surface of the carrier 16 and the inner peripheral surface of the retainer ring 17. I have. In the present embodiment, the supply port 28 is provided at a portion of the diaphragm 15 that faces the storage space C formed by the storage portion 23 of the carrier 16 (a portion exposed to the storage space). Thereby, the supply port 28 of a required size can be provided in the storage space C while the gap K is made as small as possible. The supply port 28 may be provided at only one location in the diaphragm 15 or may be provided at a plurality of locations in the circumferential direction of a portion of the diaphragm 15 facing the accommodation space C.

The supply port 28 is provided with a pair of support plates 28 a provided with openings 28 b at positions opposed to each other at positions facing the storage space C in the diaphragm 15 from above and below, and a diaphragm 15. Facing this opening 28b 02 00777

Fifteen

And an opening 15a provided at the site.

The support plate 28a may be formed, for example, in a ring shape, and a portion of the diaphragm 15 facing the accommodation space C may be sandwiched over the entire circumference in the circumferential direction, or only a part of the circumferential direction may be sandwiched. It may be configured to be sandwiched.

Here, the support plate 28 a is provided with a gap between at least one of the portion covered by the carrier 16 and the portion covered by the retainer ring 17 in the diaphragm 15. . This secures an elastically deformable area between the carrier 16 and the retainer ring 17 in the diaphragm 15, and connects the carrier 16 and the retainer ring 17 attached to the diaphragm 15 to the head body. It is possible to displace independently in the axial direction of 12.

The supply port 28 is connected to the slurry Z cleaning liquid supply mechanism 31. In the present embodiment, as shown in FIG. 1, at the supply port 28, the open end of the fluid chamber 27 side is connected to a first flexible pipe 29 at least partially having flexibility. It is connected to a second flow hole 20 b formed in the shaft 19 of the head body 12. The diaphragm 15 is allowed to be displaced in the axial direction of the head main body 12 by deforming the first flexible pipe 29.

And, as described above, the second flow hole 2 Ob is connected to the slurry cleaning liquid supply mechanism 31 for selectively supplying either the slurry or the cleaning liquid, and the supply is thereby performed. To the port 28, either the slurry or the cleaning liquid is selectively supplied from the slurry / cleaning liquid supply mechanism 31 via the second circulation hole 20b and the first flexible pipe 29. It is supposed to be.

As shown in FIG. 1, the slurry cleaning liquid supply mechanism 31 has a slurry supply source 32 and a cleaning liquid supply source 33, and these supply the slurry cleaning liquid to the second flow holes 20b, respectively. It is connected via piping 34.

Slurry slurry supply source 3 2 supplies, for example S ί 0 ₂ the alkaline slurry and C e 0 ₂ neutral slurry was used which uses or acid slurries with A 1 ₂ 0 _3,, abrasive agent E: E-C is suitable for the polishing conditions of W. The cleaning liquid supply source 33 supplies, for example, pure water, a solvent constituting a slurry, or the like as the cleaning liquid. In this embodiment, the slurry cleaning liquid supply pipe 34 is connected to the slurry supply source 32 via a first valve 36, and the slurry cleaning liquid supply source 33 is connected to a second valve 3 4. 7, one of the first and second valves 36, 37 is opened and the other is closed, so that either one of the slurry and the cleaning liquid can be selectively used. It is supplied to. Here, the mechanism for switching the supply of the slurry or the cleaning liquid to the slurry cleaning liquid supply pipe 34 is not limited to the mechanism using the first and second valves 36 and 37 as described above. Any mechanism commonly used for switching connections can be used.

Hereinafter, the polishing operation of the wafer W by the polishing apparatus using the polishing head 11 will be described.

In this polishing operation, the wafer W is first attached to a wafer attachment sheet (not shown) provided on the lower surface of the carrier 16, for example. Then, while the periphery of the wafer W is locked by the retainer ring 17, the surface thereof is brought into contact with the polishing pad 4 attached to the upper surface of the platen 3. At this time, the lower surface of the retainer ring 17 is also in contact with the polishing pad 4. Here, in the initial state, both the first and second valves 36 and 37 of the slurry cleaning liquid supply mechanism 31 are closed.

Next, the pressure in the fluid chamber 27 is adjusted by causing a fluid such as air to flow into the fluid chamber 27 from the first circulation hole 20 a by the pressure adjusting mechanism 30, and the carrier 16 and The pressing pressure of the retainer ring 17 on the polishing pad 4 is adjusted. The carrier 16 and the retainer ring 17 have a floating structure supported by the diaphragm 15 so as to be vertically displaceable, and are pressed against the polishing pad 4 by the pressure inside the fluid chamber 27. The pressure is adjustable.

Then, while adjusting the pressing J force of the carrier 16 and the retainer ring 17 against the polishing pad 4, the platen 3 is rotated and the polishing head 11 is rotated. Around this time, the first valve 36 of the slurry cleaning liquid supply mechanism 31 is opened, and the slurry is supplied from the slurry supply source 32 into the slurry cleaning liquid supply pipe 34. Thereafter, the first valve 36 is kept open during polishing of wafer W. The slurry supplied to the slurry / cleaning liquid supply pipe 34 passes through the second circulation hole 20 b provided in the shaft 19 of the head body 12 and the first flexible pipe 29. It is supplied to supply port 28.

The slurry supplied to the supply port 28 is supplied into the storage space C formed by the storage portion 23 of the carrier 16, and is guided by the storage portion 23 to the entire circumference of the outer peripheral surface 16 a of the carrier 16. As a result, the slurry is supplied from the entire circumference of the outer peripheral surface 16a to the gap K formed between the inner peripheral surface 17a of the retainer ring 17 and the entire circumference.

Thus, the slurry flows down from the gap and is directly supplied between the wafer W and the polishing pad 4, so that the wafer W is polished. Here, the flow of the slurry is shown by arrows in FIG.

Then, at an appropriate time such as when the polishing operation is completed, the supply of the slurry from the slurry cleaning liquid supply mechanism 31 to the supply port 28 is stopped, and the slurry is supplied to the supply port 28 instead. In the same manner as described above, the cleaning liquid is spread in the supply port 28 and the entire circumferential direction of the storage section 23, and the slurry remaining in the supply port 28, the storage space C, and the gap K is washed away. In the present embodiment, the supply of the slurry from the slurry supply source 32 to the slurry cleaning solution supply pipe 34 is stopped by closing the first valve 36, and the second valve 37 is opened. The cleaning liquid is supplied from the cleaning liquid supply source 33 to the slurry cleaning liquid supply pipe 34.

According to the polishing head 11 configured as described above, the wafer W and the wafer W from the gap K formed between the outer peripheral surface 16 a of the carrier 16 and the inner surface 17 a of the retainer ring 17. Since the slurry is directly supplied between the polishing pad 4 and the rotation of the platen 3 ゃ A sufficient amount of slurry is supplied between the wafer W and the polishing pad 4 without being hindered by the retainer ring 17. be able to.

Further, the slurry is guided to the accommodating portion 23 provided on the outer peripheral edge of the carrier 16 and supplied to the entire periphery in the gap K, so that the slurry W and the polishing pad 4 are supplied from the entire outer periphery of the wafer W. Thus, the slurry is supplied almost uniformly, so that the polishing amount can be made substantially uniform over the entire surface of W.

Further, since the slurry supplied between the wafer W and the polishing pad 4 is surrounded by the retainer ring 17, the retainer ring 17 receives the centrifugal force caused by the rotation of the polishing head 11 and the platen 3. Hard to leak to the outer circumference of. As a result, polishing can be performed efficiently with the minimum amount of slurry used, and expensive slurry can be used. The dose can be significantly reduced.

In addition, since the reslurry is evenly supplied to the surface of the polishing pad ⁴ by rotating the polishing head 11 itself, the slurry can be efficiently contributed to polishing.

Since the use efficiency of the slurry can be increased and the amount of use can be significantly reduced in this manner, the aggregated particles of the slurry as a total amount are reduced.

The micro-scratches generated on the surface of W can be reduced, and the polishing performance of wafer w can be improved. In addition, since the load on the polishing pad 4 due to the slurry is reduced, the life of the polishing pad 4 is extended, and the cost of the polishing pad 4 can be reduced.

Then, at an appropriate time such as when the polishing operation is completed, the supply of the slurry from the slurry cleaning liquid supply mechanism 31 to the supply port 28 is stopped, and the cleaning liquid is supplied into the supply port 28 instead. The slurry remaining in the supply port 28 and the gap K can be washed away with the washing liquid before the slurry dries, deteriorates, or solidifies.

Note that, in the above-described embodiment, an example in which the accommodating portion 23 is provided over the entire outer peripheral edge of the carrier 16 has been described. However, the present invention is not limited thereto. An accommodation section 23 may be provided.

Further, as shown in the longitudinal sectional view of FIG. 3A, instead of being provided on the outer peripheral edge of the carrier 16, the housing portion 23 may be provided on the inner peripheral edge of the retainer ring 17. As shown in the figure, it may be provided on both the carrier 16 and the retainer ring 17. In the latter case, the accommodation space C can be made larger, so that the area where the supply port 28 can be provided in the diaphragm 15 can be made even larger. The slurry cleaning liquid supply mechanism 31 is connected to the port 28 so that either the slurry supplied from the slurry supply source 32 or the cleaning liquid supplied from the cleaning liquid supply source 33 is selectively supplied. Although shown, the present invention is not limited to this, and the supply port 28 may have a configuration in which only the slurry supply source 32 is connected. Further, in the above-described embodiment, an example is shown in which the supply port 28 is configured by the pair of support plates 28 a that sandwich the diaphragm 15 and the opening 15 a of the diaphragm 15. Without connecting the first flexible pipe 29 to the fluid chamber 27 side of the opening 15a in the diaphragm 15 without providing the support plate 28a, for example. A diaphragm having a configuration in which the flexible pipe 29 itself is integrally formed may be used. Second embodiment

Hereinafter, a polishing head according to a second embodiment of the present invention will be described with reference to the drawings. Here, in the polishing head according to the present embodiment, the same or similar portions as the polishing head 1 shown in the first embodiment will be described using the same reference numerals. The polishing head 41 according to the present embodiment is different from the polishing head 1 according to the first embodiment in that, as shown in the longitudinal sectional view of FIG. It is provided with an inclined surface 23a which is gradually inclined downward as it goes toward.

Here, FIG. 4 illustrates, as an example, a case where the housing portion 23 is provided on the outer peripheral edge of the carrier 16.

According to the polishing head 41, the slurry supplied from the supply port 28 into the storage space C flows along the inclined surface 23 a of the storage part 23 as shown by an arrow in FIG. Since the slurry quickly flows toward the gap K, the slurry is less likely to stay and the slurry is less likely to dry, change in quality, and to solidify. Third embodiment

Hereinafter, a polishing head according to a third embodiment of the present invention will be described with reference to the drawings. Here, in the polishing head according to the present embodiment, the same or similar portions as the polishing head 1 shown in the first embodiment will be described using the same reference numerals. The polishing head 46 according to the present embodiment is different from the polishing head 1 according to the first embodiment in that the lower surface of the accommodation portion 23 and the accommodation portion 2 are provided as shown in the vertical sectional view of FIG. An upwardly rising wall portion 47 is provided between the peripheral surface of the peripheral portion provided with 3, that is, between the lower surface of the housing portion 23 and the outer peripheral surface 16 a of the carrier 16. 7 has a circumferential multiple Orchid 77

20

A connection path 48 for connecting the accommodating portion 23 and the outer peripheral surface 16a is provided at several places. Here, FIG. 5 illustrates, as an example, a case where the housing portion 23 is provided on the outer peripheral edge of the carrier 16.

In this configuration, the slurry supplied into the storage space C is once received by the wall portion 47 and flows in the circumferential direction along the storage portion 23. Then, when the slurry reaches the connection path 48 provided in the wall portion 47, a part of the slurry flows out into the gap K formed between the carrier 16 and the retainer ring 17 through the connection path 48. . In other words, the slurry is reliably guided along the entire circumference in the circumferential direction by the housing portion 23 and the wall portion 47 and flows out into the gap K through the connection passage 48 at various locations in the circumferential direction. It can be supplied more uniformly over the entire circumference of the gap K.

Here, when the cleaning liquid supply source 33 is connected to the supply port 28, when the cleaning liquid is supplied into the accommodating space C, the cleaning liquid is surely envisaged along the entire circumference in the same manner as the slurry, and the carrier liquid is supplied. At each point in the circumferential direction of 16, it flows out into the gap K, and the entire inside of the gap K can be cleaned.

In the polishing head 46, the connection paths 48 are provided at equal intervals in the circumferential direction of the carrier 16, for example, so that the slurry and the cleaning liquid can be supplied more uniformly over the entire circumference of the gap.

The shape of the connection path 48 is arbitrary. For example, as shown in FIG. 6A, the connection path 48 has a semicircular shape in cross section, or as shown in FIGS. 6B and 6C, a triangular shape or a square shape in cross section. It may be polygonal.

Further, as shown by a two-dot chain line in FIG. 5, an inclined surface 23a that is gradually inclined downward toward the peripheral surface may be provided on the lower surface of the housing portion 23.

Here, in the above embodiment, the case where the housing portion 23 is provided on the outer peripheral edge of the carrier 16 has been described. However, the present invention is not limited to this, and the housing portion 23 is provided on the inner peripheral edge of the retainer ring 17. In the same manner, the wall portion 47 having the connection path 48 can be provided in the housing portion 23. Fourth embodiment

Hereinafter, a polishing head according to a fourth embodiment of the present invention will be described with reference to the drawings. You. Here, in the polishing head according to the present embodiment, the same or similar parts as the polishing head 1 shown in the first embodiment will be described using the same reference numerals. FIG. 7 is a longitudinal sectional view showing the configuration of the polishing head 51 according to the present embodiment. The polishing head 51 according to the present embodiment is the same as the polishing head 1 according to the first embodiment, except that at least one of the carrier 16 and the retainer ring 1Ί And a cleaning liquid supply channel 52 for supplying at least one of the slurry and the cleaning liquid. This channel 52 is also connected to at least one of the slurry supply source 32 and the cleaning liquid supply source 33. It was done.

In FIG. 7, the carrier 16 is provided with a first flow path (flow path A) 52a, and the retainer 17 is provided with a second flow path (flow path B) 52b. Is shown. In this polishing head 51, the carrier 16 is provided with a first flow path 52a extending from the upper surface 16b to the outer peripheral surface 16a, and the first flow path 52a is provided with a first flow path 52a. The opening end on the 6b side is connected to the second circulation hole 20b of the head body 12 by a second flexible pipe 53 having at least a part of elasticity.

In the head body 12, the top plate 13 is provided with a joint portion 54 to which a slurry / cleaning liquid supply pipe 34 is connected, and the top plate 13 and the peripheral wall portion 14 are joined together. There is provided a head body conduit 56 which communicates with the inner peripheral surface of the step portion 14a of the peripheral wall portion 14. The retainer ring 17 is provided with a second flow path 52 b communicating from the upper face 17 b to the inner peripheral face 17 a, and the second flow path 52 b has an upper face 17 b side. The open end of the head body pipe 56 is connected to the head main body pipe 56 by a third flexible pipe 57 having at least a part of elasticity.

In this configuration, the slurry and the cleaning liquid can be supplied into the gap K not only from the supply port 28 provided in the diaphragm 15 but also from the flow path 52 provided in the carrier 16 or the retainer ring 17. As a result, it is possible to maintain the polishing performance by securing the flow rates of the slurry and the cleaning liquid.

Note that the connection form of the flow path 52, the slurry supply source 32, and the cleaning liquid supply source 33 shown in the above embodiment is an example, and any other form can be adopted. Fifth embodiment

Hereinafter, a polishing head according to a fifth embodiment of the present invention will be described with reference to the drawings. Here, FIG. 8 is a longitudinal sectional view showing a configuration of the polishing head according to the present embodiment, FIG. 9 is a front end view of the polishing head according to the present embodiment, and FIG. 10 is a polishing head according to the present embodiment. FIG. 2 is a partially enlarged view schematically showing a main part of the door. The polishing head according to the present embodiment is used in place of the polishing head 5 in, for example, the conventional polishing apparatus shown in FIG.

As shown in FIG. 8, the polishing head 61 according to the present embodiment includes a head body 12 including a top plate 13 and a peripheral wall portion 14 formed in a cylindrical shape, and a head body. Diaphragm 15 stretched inside 1 2 and disc-shaped carrier 16 fixed to the lower surface of diaphragm 15 and holding one surface of ゥ:! Is provided concentrically between the inner wall of the peripheral wall portion 14 and the outer peripheral surface 16 a of the carrier 16. During polishing, the inner peripheral surface 17 a contacts the carrier 16 with the polishing pad 4 while polishing. And an annular linear ring 17 for locking the outer periphery of the wafer W to be held.

The head body 12 is composed of a disk-shaped top plate 13 and a cylindrical peripheral wall 14 fixed below the outer periphery of the top plate 13, and the lower end of the head body 12 is It is open and hollow. The top plate 13 is coaxially fixed to a shaft 19 connected to the main body of the polishing apparatus, and the shaft 19 has a first flow hole 20 a and a first communication hole 20 a communicating with the pressure adjusting mechanism 30. A second flow hole 20b communicating with the slurry Z cleaning liquid supply mechanism 31 is formed in the vertical direction. Further, the top plate 13 is provided with a joint 54 for connection to the slurry Z cleaning liquid supply mechanism 31. From the joint portion 54, a head main body conduit 56 communicating with the lower surface of the top plate portion 13 is formed. Further, a step portion 14a is formed at the lower end of the peripheral wall portion 14 over the entire circumference. The diaphragm 15 made of an elastic material such as fiber reinforced rubber is formed in an annular or disk shape, and its outer peripheral edge is formed by a step 14 a and a step 14 formed on the inner wall of the peripheral wall 14. It is fixed to the head body 12 by being sandwiched between the diaphragm fixing ring 26 attached to a.

A fluid chamber 27 is formed above the diaphragm 15, and the fluid chamber 27 is communicated with the pressure adjusting mechanism 30 by a first flow hole 20 a formed in the shaft 19. Have been. Then, by supplying a fluid such as air into the fluid chamber 27 from the pressure adjusting mechanism 30 through the first circulation hole 20a, the pressure inside the fluid chamber 27 is adjusted. .

Then, as shown in FIGS. 8 to 10, the carrier 16 is used to supply a slurry or a cleaning liquid between the outer peripheral surface 16 a and the inner peripheral surface a of the retaining ring 17. A first flow path (flow path A) 62 is formed as a flow path.

The first flow path 62 includes a vertical portion 62 a formed along the axis of the carrier 16 from the center of the upper surface 16 b to the vicinity of the lower surface of the carrier 16, and a lower portion of the vertical portion 62 a Along the lower surface of the carrier 16, there is a horizontal portion 62b provided substantially radially toward the outer peripheral side. In the present embodiment, as shown in FIG. 9, a total of four horizontal portions 62 b are formed at substantially equal angles in the circumferential direction of the carrier 16.

As shown in FIG. 8, in the first flow path 62, the open end on the upper surface 16b side is connected through a first flexible pipe 53 having at least a part of flexibility. Connected to a second flow hole 20 b formed in the shaft 19 of the main body 12. Here, the carrier 16 is allowed to be displaced in the head axis direction due to the deformation of the diaphragm 15 due to the deformation of the first flexible pipe 53.

Then, as described above, the second circulation hole 2 Ob is connected to the slurry cleaning liquid supply mechanism 31 that selectively supplies either the slurry or the cleaning liquid, thereby forming The one flow path 62 selectively supplies either one of the slurry and the cleaning liquid from the slurry cleaning liquid supply mechanism 31 via the second circulation hole 20b and the first flexible pipe 53. It is being supplied. When the diameter of the first flow path 62 is smaller than 2 mm, the slurry is likely to be clogged, and when the diameter is larger than 10 mm, the strength of the carrier 16 is reduced. It is desirable to do the following.

The outer surface 16 a of the carrier 16 is connected to the first flow path 62, JP02 / 00777

twenty four

A first groove (groove A) 64 for guiding the slurry or the cleaning liquid supplied from the flow path 62 of the first embodiment is formed over the entire circumference. The lower inner surface 64 a of the first groove 64 has a shape that is depressed downward as shown in FIG. 10, whereby the first inner surface 64 a is moved from the first channel 62 to the first channel 62. The slurry or the cleaning liquid supplied to the groove 64 is temporarily held, and flows along the first groove 64. Here, FIG. 10 shows a state of holding the slurry S by the first groove 64 as an example.

The retainer ring 17 is formed in a substantially annular shape as shown in FIG. 8 and has a slight gap between the retainer ring 17 and the inner wall of the peripheral wall portion 14 and the outer peripheral surface 16 a of the carrier 16. These are arranged concentrically. Here, a gap formed between the carrier 16 and the retaining ring 17 is indicated by a symbol K (see FIGS. 9 and 10). The retainer ring 17 is attached to the diaphragm 15 by being fixed to the retainer ring fixing ring 22 provided on the upper surface of the diaphragm 15 with the diaphragm 15 interposed therebetween. ing. Here, the retainer ring fixing ring 22 and the diaphragm 15 are provided with a second flexible pipe 57 (described later) at a position facing an opening end of a second flow path (flow path B) 65 described later. A through hole H is formed to allow the air to pass therethrough.

In addition, the retainer ring 17 has a plurality of circumferentially arranged gaps K formed between the inner peripheral surface 17a and the outer peripheral surface of the carrier 16 and a flow path for supplying the slurry or the cleaning liquid. As a second flow path 65 is formed. The second flow path 65 communicates from the upper surface 17b of the retainer ring 17 to the inner peripheral surface 17a. In the present embodiment, as shown in FIG. 9, a total of four second flow paths 65 are formed at substantially equal angles in the circumferential direction of the retainer ring 17. A second flexible pipe 57 having a part of flexibility is passed through the through hole H of the retainer ring fixing ring 22 and the diaphragm 15. The open end on the upper surface 17 b side is connected to a head body conduit 56 formed on the top plate 13 of the head body 12 via a second flexible pipe 57. ing. Here, the retainer ring 17 is allowed to be displaced in the head axis direction due to the deformation of the diaphragm 15 due to the deformation of the second flexible pipe 57.

The other end of the second flexible piping 57 has a top plate portion 13 of the head body 12. „C

PCT / JP02 / 00777

twenty five

Is connected to the slurry Z cleaning liquid supply mechanism 31 through a head main body conduit 56 formed in the main body, whereby the second flow path 65 is connected to the head main body conduit 56 and the second main body conduit 56. The slurry / cleaning liquid supply mechanism 31 selectively supplies either one of the slurry and the cleaning liquid via the flexible pipe 57.

If the diameter of the second flow path 65 is smaller than 2 mm, the slurry is likely to be clogged.If the diameter is larger than 1 O mm, the strength of the retainer ring is reduced. It is desirable that

Also, an inner peripheral surface 17a of the retainer ring 17 is connected to the second flow path 65, and the second groove (5) for guiding the slurry or cleaning liquid supplied from the second flow path 65. Grooves B) 68 are formed over the entire circumference. As shown in FIG. 10, the lower inner surface 68 a of the second groove 68 has a shape that is recessed downward, whereby the second flow path 65 is moved from the second flow path 65 to the second flow path 65. The slurry or the cleaning liquid supplied to the second groove 68 is temporarily held, and flows along the second groove 68.

As shown in FIG. 8, the slurry Z cleaning liquid supply mechanism 31 has a slurry supply source 32 and a cleaning liquid supply source 33, which are respectively provided with a second circulation hole 20b and a joint section 5b. 4 is connected via a slurry cleaning liquid supply pipe 3 4. Slurry slurry supply source 3 2 supplies, for example S i 0 ₂ alkaline slurry and C e 0 ₂ neutral slurry with using or acidic slurries using AI ₂ 0 _3,, abrasive granules, etc. It is considered to be suitable for the polishing conditions of e-W, such as slurry using The cleaning liquid supply pipe 34 supplies, for example, pure water, a solvent constituting the slurry, or the like as the cleaning liquid.

In this embodiment, the slurry cleaning liquid supply pipe 34 is connected to the slurry supply source 32 via a first valve 36, and the slurry cleaning liquid supply source 33 is connected to a second valve 3 4. 7, one of the first and second valves 36, 37 is opened and the other is closed, so that either one of the slurry and the cleaning liquid can be selectively used. It is supplied to. Here, the mechanism for switching the supply of the slurry or the cleaning liquid to the slurry cleaning liquid supply pipe 34 is not limited to the mechanism using the first and second valves 36 and 37 as described above. Any mechanism commonly used for switching connections can be used. In the case of polishing the wafer W by a polishing apparatus using such a polishing head 61, first, c-wa W is, for example, a wafer-adhering sheet (not shown) provided on the lower surface of the carrier 16. Adhered to. Then, while the periphery of the wafer W is locked by the retainer ring 17, the surface thereof is brought into contact with the polishing pad 4 attached to the upper surface of the platen 3. At this time, the lower surface of the relining ring 17 is also in contact with the polishing pad 4. Here, in the initial state, the first and second valves 36 and 37 of the slurry cleaning liquid supply mechanism 31 are both closed.

Next, the pressure in the fluid chamber 27 is adjusted by flowing a fluid such as air from the first flow hole 20 a into the fluid chamber 27, and the pressure is adjusted to the carrier 16 and the polishing pad 4 of the retainer ring 17. Adjust the pressing pressure of. The carrier 16 and the retainer ring 17 have a floating structure that is supported by the diaphragm 15 and can be displaced in the vertical direction. The carrier 16 and the retainer ring 17 are applied to the polishing pad 4 by the pressure inside the fluid chamber 27. Pressing pressure can be adjusted.

Then, while adjusting the pressing pressure of the carrier 16 and the retainer ring 17 against the polishing pad 4, the platen 3 is rotated, and the polishing head 61 is rotated. At the same time, the first valve 36 of the slurry Z cleaning liquid supply mechanism 31 is opened, and the slurry is supplied from the slurry supply source 32 into the slurry cleaning liquid supply pipe 34. Thereafter, the first valve 36 is kept open during polishing of wafer W. Slurry Z The slurry supplied to the cleaning liquid supply pipe 34 is supplied to the second circulation hole 20b provided in the shaft 19 of the head body 12 and the top plate of the head body 12 It is also supplied into the head body conduit 56 through the joint 54 provided in 13.

Then, the slurry supplied to the second flow hole 20 b is supplied to the first flow path 62 of the carrier 16 through the first flexible pipe 53. The slurry guided to the outer peripheral surface 16 a by the first flow path 62 is guided to the entire periphery of the outer peripheral surface 16 a by the first groove 64 formed in the outer peripheral surface 16 a, Since it flows down from the entire circumference of 16a, the gap K formed between the outer circumference 16a and the inner circumference 1a of the retainer ring 17 Slurry is supplied all around. In addition, by supplying the slurry into the first flow path 62 in this way, the carrier 16 is cooled by the slurry flowing in the first flow path 62. In the present embodiment, the horizontal portion 62b of the first flow path 62 is formed close to the lower surface of the carrier 16 and is formed substantially radially from the center of the carrier 16 to the outer periphery. In the carrier 16, the slurry is cooled over the entire vicinity of the lower surface receiving the processing heat. Here, in consideration of effective cooling of the carrier 16, it is preferable that the horizontal portion 62 b be provided as much as possible within a range that does not reduce the strength of the carrier 16, and be provided close to the lower surface side.

Furthermore, the centrifugal force generated by the rotation of the polishing head 61 causes the slurry supplied into the horizontal portion 62b to be sent out toward the outer peripheral surface 16a. Supply is performed smoothly.

On the other hand, the slurry supplied to the head main body conduit 56 is supplied to the second flow passage 65 of the retainer ring 17 through the second flexible piping 57. The slurry guided to the inner peripheral surface 17a by the second flow path 65 is guided to the entire periphery of the inner peripheral surface 17a by the second groove 68 formed in the inner peripheral surface 17a. Then, the slurry flows down from the entire circumference of the inner peripheral surface 17a, so that the slurry is supplied to the entire circumference in the gap K formed between the inner peripheral surface 17a and the outer peripheral surface 16a of the carrier 16. You. By supplying the slurry into the gap K in this manner, the slurry is directly supplied between the wafer W and the polishing pad 4 without being hindered by the rotating and re-ringing 17 of the platen 3.

Then, at an appropriate time such as when the polishing operation is completed, the supply of the slurry from the slurry / cleaning liquid supply mechanism 31 to the first and second flow paths 62, 65 is stopped, and instead, the first, By supplying the cleaning liquid into the second flow paths 62, 65, the cleaning liquid spreads throughout the first and second flow paths 62, 65 and the entire circumferential direction of the gap K in the same manner as the slurry. As a result, the slurry remaining in the first and second flow paths 62 and 65 and the gap K can be washed away. In the present embodiment, by closing the first valve 36, the supply of the slurry from the slurry supply source 32 to the slurry / cleaning liquid supply pipe 34 is stopped, and by opening the second valve 37, Slurry from cleaning liquid supply source 3 3 Supply cleaning liquid to cleaning liquid supply pipe 34.

According to the polishing head 61 configured as described above, the slurry is formed outside the carrier 16. By being supplied into the gap K formed between the peripheral surface 16 a and the inner surface 17 a of the retainer ring 17, the rotation of the platen 3 and the retainer ring 17 do not hinder the rotation. The slurry is directly supplied between the pad W and the polishing pad 4.

Thereby, a sufficient amount of slurry can be supplied between the wafer W and the polishing pad 4.

The slurry is introduced into the first groove 64 formed on the outer peripheral surface 16 a of the carrier 16 and the second groove 68 formed on the inner peripheral surface 17 a of the retainer ring 17. And the slurry is supplied to the entire circumference in the gap K, so that the slurry is almost uniformly supplied between the wafer W and the polishing pad 4 from the entire circumference of the wafer W, and the entire surface of the wafer W The polishing amount can be made substantially uniform.

Furthermore, since the slurry supplied between the wafer W and the polishing pad 4 is surrounded by the retainer ring 17, the retainer ring 17 is not affected by the centrifugal force generated by the rotation of the polishing head 61 and the platen 3. Hard to flow to the outer periphery of Therefore, polishing can be performed efficiently with the minimum amount of slurry used, and the amount of expensive slurry used can be reduced.

The reslurry is evenly supplied to the surface of the polishing pad 4 by the rotation of the polishing head 61 itself, so that the slurry can efficiently contribute to polishing.

Further, since the slurry is supplied into the first flow path 62, the carrier 16 is cooled by the slurry flowing in the first flow path 62, so that the thermal deformation of the carrier 16 is reduced. Thus, the polishing accuracy of wafer W can be improved.

Since the horizontal portion 62b of the first flow path 62 is formed substantially radially from the center of the carrier 16 toward the outer periphery, the slurry is applied to the entire vicinity of the lower surface of the carrier 16 receiving the processing heat. Cooling can be performed, and the thermal deformation of the carrier 16 can be suppressed more effectively. Further, when polishing the wafer W, the slurry can be smoothly supplied to the outer peripheral surface 16a of the carrier 16 by the centrifugal force generated by the rotation of the polishing head 61.

Then, at an appropriate time such as when the polishing operation is completed, the supply of the slurry from the slurry cleaning liquid supply mechanism 31 to the first and second flow paths 62, 65 is stopped. The slurry remaining in the first and second flow paths 62, 65 and the gap K is dried by supplying the cleaning liquid into the first and second flow paths 62, 65. Alternatively, it can be washed away with a cleaning solution before deterioration.

In the above embodiment, the head body 12 has a structure in which the joint part 54 provided on the top plate part 13 and the second flow path 65 of the retainer ring 17 are connected. A head main body conduit 56 communicating with the fluid chamber 27 was formed in the plate portion 13, and the head main body conduit 56 and the second flow path 65 were arranged in the fluid chamber 27. An example of connection by the second flexible piping 57 was shown. However, the present invention is not limited to this. For example, instead of providing a head body conduit 56 in the head body 12 as in a polishing head 71 shown in FIG. A head main body conduit 72 is formed from the joint portion 54 to the inner peripheral surface of the step portion 14a of the peripheral wall portion 14, and the upper surface of the retainer ring 17 is formed in the second flow path 65. Open the end that had been opened to 17 b to the outer peripheral surface 17 c, and connect this open end and the open end of the step 14 a side of the head body conduit 72 to the second flexible pipe 57. Connection may be used. Sixth embodiment

Hereinafter, a polishing apparatus according to a sixth embodiment of the present invention will be described with reference to the drawings. Here, FIG. 12 is a perspective view showing the configuration of the polishing apparatus according to the present embodiment. In the polishing apparatus according to the present embodiment, the same or similar parts as those of the conventional polishing apparatus shown in FIG. 15 will be described using the same reference numerals.

As shown in FIG. 12, a polishing apparatus 111 according to the present embodiment has a polishing pad 4 provided on a platen 3 attached to a center shaft. A polishing head rotated by a head driving mechanism (not shown) is disposed at a position eccentric from the center axis of the polishing pad, and a spraying device 112 for blowing gas or slurry onto the surface of the polishing pad 4 is provided. The configuration is provided.

The spraying device 1 1 2 includes a nozzle 1 13 for discharging gas or slurry, and a nozzle moving mechanism 1 1 4 for moving the nozzle 1 13 toward the surface of the polishing pad 4 while facing the polishing pad 4. And A plurality of sets of the nozzles 113 and the nozzle moving mechanism 114 may be provided. A gas supply source 116 is connected to the nozzle 113 through a first pipe 117.

The gas supply source 116 supplies a gas that does not contaminate or deteriorate the polishing pad 4, such as clean dry air or an inert gas.

The first pipe 1 17 is provided with a first valve 1 18 that controls the supply of gas to the nozzle 1 13 and the stop of supply by opening and closing the first valve 1 18 You can do it. The first valve 118 may be configured to be opened and closed manually, or may be configured to be opened and closed by a control device (not shown).

The nozzle moving mechanism 114 moves the nozzle 113 on the surface of the polishing pad 4 at least over an area used for polishing the workpiece, and is an optional nozzle generally used for moving members. Can be adopted.

In the present embodiment, the nozzle moving mechanism 114 includes a support shaft 121 provided on the side of the platen 3 and an arm 122 supporting one end 122 a on the support shaft 121. And a drive device (not shown) for rotating the support shaft 122 around the axis. The other end 1 2 2b of the arm 1 2 2 is provided with a nozzle 1 13, and the rotating shaft 1 2 1 is rotated by the driving device, so that the polishing pad 4 is supported on the support shaft 1 2 1 as a fulcrum. The nozzle 1 13 provided on the other end 1 2 2 b is swung on a plane along the surface of the polishing pad 4 so as to be moved on a plane along the surface of the polishing pad 4. Here, the arm 1 2 2 moves the other end 1 2 2 b from the position facing the rotation center C of the polishing pad 4 toward the radially outer peripheral side of the polishing pad 4 to at least polish the material to be polished. It can be moved to a position opposite to the radially outermost position of the used area.

Hereinafter, a polishing process of a material to be polished by the polishing apparatus 111 configured as described above will be described. The polishing apparatus 111 has a feature in an initial polishing step after dressing the polishing pad 4 or in a polishing step performed after the previous polishing step. In the present embodiment, pure water PW is used as a liquid to be supplied onto polishing pad 4 during dressing and rinsing.

In the polishing process, in the initial state, the nozzles 1 13 are rotating while the polishing pad 4 is rotating. It is located at a position facing the heart C.

By blowing gas from the nozzles 11 to the surface of the polishing pad 4 in this state, the pure water PW is swept around the rotation center C of the polishing pad 4 by the blown gas.

Before or after this, the platen 3 is driven to rotate the polishing pad 4.

By moving the nozzle 113 toward the radially outer peripheral side of the polishing pad 4 by the nozzle moving mechanism 114 while the polishing pad 4 is rotated in this manner, the rotation center C of the polishing pad 4 is changed. The gas is blown spirally from the center of the polishing pad 4 toward the radially outer peripheral side, and the pure water PW is flushed from the center of rotation C of the polishing pad 4 toward the radially outer peripheral side.

Here, the distance that the nozzle moving mechanism 114 moves the nozzle 113 toward the radially outer peripheral side of the polishing pad 4 while the polishing pad 4 rotates is determined by the amount of pure water PW on the surface of the polishing pad 4. The area D 1 where the water is swept away and the area D 2 where the pure water PW is newly swept away by the gas are within a range that is continuous in the radial direction, whereby the pure water on the polishing pad 4 is formed. PW is being washed away without exception.

The spraying device 112 blows gas from the center of rotation C of the surface of the polishing pad 4 to at least a radially outermost position of a region used for polishing the material to be polished.

Then, after removing the pure water PW from at least the region used for polishing the workpiece on the surface of the polishing pad 4, the slurry is supplied to the surface of the polishing pad 4 in the same manner as in the conventional polishing apparatus 1. While polishing, a new material to be polished is polished. According to the polishing apparatus 111 configured as described above, the gas is blown onto the surface of the polishing pad 4 by the spraying apparatus 1 1 2 so that the gas is applied onto the polishing pad 4 after dressing or after the previous polishing step. The remaining pure water PW can be removed, and even if the slurry is supplied onto the polishing pad 4, the slurry is not diluted by the pure water PW. Conventionally, the amount of slurry that had been supplied on the polishing pad 4 to remove the pure water PW from the polishing pad 4 becomes unnecessary, and the slurry consumption is reduced by 3 to 5 OmL while maintaining the polishing performance. Zm ί n, desired L <^ i 7 ~ 20 ml / min (approximately 3% ~ 50% compared to conventional polishing) Can be reduced.

Furthermore, in the silicon wafer having a SiGe layer formed on the surface, the surface roughness is strictly required and higher flatness is required. Therefore, the present invention is particularly effective for polishing such a silicon wafer. Further, the polishing pressure can be suppressed to 10 to 50 kPa, preferably 13 to 40 kPa.

Here, in the above-described embodiment, the nozzle 113 is directed to the surface of the polishing pad 4. However, the nozzle 113 is inclined toward the radially outer peripheral side with respect to the surface of the polishing pad 4. You may. In this case, the gas is discharged from the nozzles 11 to 13 toward the radially outer peripheral side of the polishing pad 4, so that the pure water PW on the polishing pad 4 is directed toward the radially outer peripheral side of the polishing pad 4. It can be washed away effectively.

Further, in the above-described embodiment, the spraying device 1 12 is configured to connect the gas supply source 116 to the nozzle 113 and blow the gas to the polishing pad 4. However, the present invention is not limited to this. Instead of the gas supply source 116, a slurry supply source for supplying slurry may be connected to the nozzle 113, and the slurry may be sprayed from the nozzle 113 to the polishing pad 4.

In this case, by spraying the slurry on the surface of the polishing pad 4 with the spraying device 1 1 2, the slurry sprayed on the surface of the polishing pad 4 flushes the pure water PW on the polishing pad 4 to remove the pure water PW. Since the slurry can be replaced with a slurry, it is more efficient than the conventional method in which the slurry is simply supplied onto the polishing pad 4 and the pure water PW is flushed from the polishing pad 4 by the flow of the slurry. Pure water PW can be washed away, and the amount of slurry used for replacing pure water PW with slurry can be reduced.

In the above-described embodiment, the nozzle moving mechanism 114 is configured to move the nozzle 113 in the radial direction of the polishing pad 4. However, the present invention is not limited to this. The nozzle 4 may be configured so that the nozzles 11 and 13 are moved at least over the entire area of the surface of the polishing pad 4 used for polishing the workpiece. In this case, with the polishing pad 4 stationary, the nozzle 113 is moved by the nozzle moving mechanism 114 while discharging the gas or slurry from the nozzle 113, and at least on the above-mentioned region on the surface of the polishing pad 4. To remove pure water PW and slurry in this area. Spraying. Seventh embodiment

Hereinafter, a polishing apparatus according to a seventh embodiment of the present invention will be described with reference to the drawings. Here, FIG. 13 is a longitudinal sectional view showing the configuration of the polishing apparatus according to the present embodiment. In the polishing apparatus according to the present embodiment, the same or similar parts as those of the polishing apparatus 111 shown in the sixth embodiment will be described using the same reference numerals.

As shown in FIG. 13, the polishing apparatus 13 1 according to the present embodiment is different from the polishing apparatus 1 11 shown in the sixth embodiment in that the nozzle 1 13 and the gas supply source 1 16 are used alone. Instead, a slurry supply source 1 32 was connected.

Slurry supply source 1 3 2 is connected to the nozzle ¹ 1 3 through the second pipe 1 3 3. The second pipe 13 3 is provided with a second valve 13 4 .By opening and closing the second valve 13 4, the supply of the slurry to the nozzle 13 and the stop of the supply are stopped. You can control it.

In the present embodiment, the nozzle body 1 13 a of the nozzle 1 13 is provided with a first flow path 1 13 c connecting the first pipe 1 17 and the discharge port 1 13 b. The first flow path 113c is connected to a second flow path 113d leading to the second pipe 133.

The nozzle 113 supplies gas from the first pipe 113 to the first flow path 113c, and utilizes the bench lily effect to make the second pipe 133 from the second pipe 133. The slurry supplied into the flow path 113d is sucked out and discharged from the discharge port 113b.

That is, by sending only the gas from the gas supply source 116 to the nozzle 113, only the gas is discharged from the nozzle 113, and the slurry is further supplied while the gas is sent to the nozzle 113. By supplying the slurry from the source 13 2, the slurry is discharged from the nozzle 13.

In this configuration, the slurry supplied from the slurry supply source 132 into the second pipe 133 does not come into contact with the gas, and the slurry dries and solidifies in the second pipe 133. I won't. Orchid 77

34

Further, a cleaning liquid supply source 136 for supplying a cleaning liquid such as pure water, for example, is connected to the nozzle 113 via a third pipe 137. The third pipe 1337 is provided with a third valve 1338.By opening and closing the third valve 1338, the supply of the cleaning liquid to the nozzle 113 and the stop of the supply are stopped. Can be controlled.

Here, the second and third valves 13 4 and 13 8 may be configured to be manually opened and closed, or may be configured to be opened and closed by a control device (not shown). In the embodiment, the third pipe 13 7 is connected to the second pipe 13 3 at a position near the connection with the nozzle 11 3, and the third pipe 13 7 is connected to the nozzle 11 via the second pipe 13 3 Connected with 3. As a result, the cleaning liquid is supplied from the cleaning liquid supply source 1336 to the second flow path 113d of the nozzle 113 through the third pipe 133 and the second pipe 133. It is discharged from the discharge port 113 b through one channel 113 c.

Hereinafter, a polishing process of a material to be polished by the polishing apparatus 13 1 configured as described above will be described.

This polishing apparatus 131, like the polishing apparatus 111 shown in the sixth embodiment, has a feature in the first polishing step after dressing or in the polishing step performed after the previous polishing step. ing.

In this polishing step, first, pure water PW on the polishing head 4 is removed by gas, as in the polishing step by the polishing apparatus 11.

Thereafter, the nozzle 1 13 is again moved by the nozzle moving mechanism 114 so that the nozzle 113 faces the rotation center C of the polishing pad 4 (or the radially innermost peripheral position of the region used for polishing the workpiece in the polishing pad 4). Position.

Then, in this state, the slurry is sprayed from the nozzles 113 onto the surface of the polishing pad 4, and the platen 3 is driven to rotate the polishing pad 4, and the nozzle 113 is polished by the nozzle moving mechanism 114. The pad 4 is moved toward the radially outer peripheral side. As a result, the slurry is sprayed spirally from the rotation center C (or the radially inner peripheral side) of the polishing pad 4 toward the radially outer peripheral side.

Here, while the polishing pad 4 rotates, the nozzle moving mechanism 1 1 4 moves the nozzle 1 1 3 0777

35

The distance by which the slurry is moved to the outer peripheral side in the radial direction of the polishing pad 4 is within a range in which the area where the slurry is already sprayed on the surface of the polishing pad 4 and the area where the slurry is newly sprayed are continuous in the radial direction. As a result, the slurry can be evenly sprayed on the surface of the polishing pad 4.

At an appropriate time, such as after finishing the spraying of the slurry, the cleaning liquid is supplied from the cleaning liquid supply source 1 36 while the nozzle 1 13 is retracted from above the polishing pad 4 by the nozzle moving mechanism 1 14. It is supplied into the nozzle 113 and the slurry inside the nozzle 113 is washed away with the cleaning liquid, so that it is ready for the next use. By washing the inside of the nozzle 113 in this way, clogging of the slurry inside the nozzle 113 can be prevented. According to the polishing apparatus 13 1 configured as described above, the spraying apparatus 1 12 is configured to selectively blow one of the gas and the slurry to the polishing pad 4. After the gas is blown to remove the pure water PW on the polishing pad 4, the slurry is sprayed on the polishing pad 4 so that the slurry not diluted by the pure water PW on the polishing pad 4 as shown in Fig. 13 Layer P can be formed. In this polishing apparatus 13 1, the slurry P is formed directly on the polishing pad 4 by spraying the slurry on the polishing pad 4. The consumption of the slurry can be reduced as compared with the method of forming the slurry layer by the flow. Example

Example 1

Hereinafter, when polishing the wafer W by the polishing method according to the present invention using the polishing head according to the present invention (hereinafter referred to as polishing according to the present invention), and using the conventional polishing head, The polishing performance was compared between the case where the wafer W was polished by the conventional polishing method (hereinafter referred to as conventional polishing). Here, in this polishing test, the polishing head 61 shown in the fifth embodiment was used as the polishing head according to the present invention.

In conventional polishing, in order to obtain sufficient polishing performance, it is necessary to supply a slurry flow rate of about 100 mL Zmin per polishing head. Polishing, the slurry flow rate can be reduced to 1 Om L Zmin per polishing head without deteriorating the polishing performance, which is about 110 compared to conventional polishing. Was.

In addition, in the polishing according to the present invention, since the wafer W can be polished in such a state that the amount of the slurry used is remarkably reduced, the total amount of slurry aggregated particles is reduced. Micro scratches generated in W are reduced.

As a result, the surface roughness (PV value) of the wafer W can be reduced, and good polishing performance can be obtained. Since the silicon wafer having the SiGe layer formed on the surface has strict surface roughness specifications and requires higher flatness, the present invention is particularly effective for polishing such a silicon wafer. Example 2

In the first polishing step after dressing or the polishing step after the previous polishing step using the polishing apparatus 111 according to the present invention, pure water on the polishing pad 4 is sprayed using the spraying apparatus 112. Polishing tests were carried out under the same polishing conditions for polishing after removal and polishing when replacing with pure water and slurry without using the spraying device. The polishing performance was compared. The results are shown below.

Here, as the polishing performance, attention was paid to the polishing rate and in-plane uniformity (flatness) of the material to be polished, and the relationship between the flow rate of the slurry supplied onto the polishing pad 4 and the polishing performance was also verified.

As shown in Fig. 14, under the condition that the flow rate of the slurry was 100 cc Zm η η, the spraying device 12 and the spraying device 12 were not used. Although the polishing rate and in-plane uniformity were better when the spraying device 12 was used, the difference was small.

However, as the flow rate of the slurry is reduced, the polishing rate and in-plane uniformity are clearly reduced when the spraying device 12 is not used, whereas the spraying device 1 12 is not used. When used, the reduction in polishing rate and the reduction in in-plane uniformity were slight. This tendency becomes more remarkable as the flow rate of the slurry is reduced, and under the condition that the flow rate of the slurry is 10 cc Zmin, the polishing rate when the spraying device 12 is not used is the highest. It is 40% lower than when the birds were high.

On the other hand, when the spraying device 112 was used, the polishing rate was reduced by only 20% compared to the case where the polishing rate was the highest, even if the flow rate of the slurry was reduced. . Also, the degree of deterioration of the in-plane uniformity is reduced. This is because when the spraying device 112 is not used, the slurry is diluted by pure water remaining on the polishing pad 4 and polishing is performed in a state where there is a difference in the slurry concentration at various points of the polishing pad 4. On the other hand, when the spraying device 1 1 and 2 were used, the slurry on the polishing pad 4 was not diluted, and the slurry concentration at each part of the polishing pad 4 was uniform. This is probably because polishing was performed in this state.

When the flow rate of the slurry is sufficiently ensured, the amount of the slurry is larger than the amount of pure water remaining on the polishing pad. Although it can be maintained, when the flow rate of the slurry decreases, the concentration of the slurry decreases when the spraying device 1 12 is not used, so the difference in polishing performance becomes remarkable as the flow rate of the slurry decreases. It seems to have appeared.

As described above, according to the polishing apparatus of the present invention, in the first polishing step after dressing or in the polishing step performed after the previous polishing step, by using the spraying device 12, the condition that the flow rate of the slurry is small is used. Since the polishing performance can be maintained while maintaining the slurry concentration at a proper level even below, the flow rate of the slurry can be reduced and the consumption of the slurry can be reduced. Industrial applicability

According to the polishing head and the polishing method of the present invention, at the time of polishing the workpiece, the slurry passes through the liquid supply passage between the outer peripheral surface of the carrier and the inner peripheral surface of the retainer ring, that is, the outer periphery of the workpiece. Is supplied to the gap located at The slurry is directly and sufficiently supplied between the workpiece and the polishing pad without being hindered by rolling or retainer ring.

Also, the slurry supplied between the workpiece and the polishing pad is surrounded by the retainer ring, and flows out to the outer periphery of the retainer ring even when subjected to centrifugal force due to the rotation of the polishing head and the platen. The slurry can be used efficiently because it is difficult to use. Therefore, polishing can be efficiently performed with a minimum amount of slurry used, and the amount of expensive slurry used can be significantly reduced.

By rotating the polishing head itself, the slurry is evenly supplied to the surface of the polishing pad, and the slurry can be efficiently contributed to polishing. In addition, by providing a slurry cleaning liquid supply mechanism for selectively supplying either the slurry or the cleaning liquid to the liquid supply path, the slurry is supplied to the liquid supply path by the slurry cleaning liquid supply mechanism during polishing. At an appropriate time, such as when the polishing operation is completed, the supply of the slurry from the slurry cleaning liquid supply mechanism to the liquid supply path is stopped, and the cleaning liquid is supplied to the liquid supply path instead. The slurry remaining in the gap between the outer peripheral surface of the carrier and the inner peripheral surface of the retainer ring can be washed away with the cleaning liquid before the slurry is dried or deteriorated. Also, by providing the groove, the outer peripheral surface of the carrier is provided. Alternatively, the slurry supplied to the inner peripheral surface of the retainer ring flows down from the entire periphery by the groove, so that the entire peripheral surface of the workpiece is polished. Luo becomes Rukoto slurry is substantially uniformly supplied between the polishing pad and the object of polishing, it can be made substantially uniform amount of polishing the entire surface of the object to be polished.

Further, when the flow path A is formed substantially radially from the center of the carrier toward the outer periphery, the entire carrier can be cooled by the liquid, and the thermal deformation of the carrier can be more effectively suppressed. it can. Further, when polishing the material to be polished, the slurry can be smoothly supplied to the outer peripheral surface of the carrier by the centrifugal force generated by the rotation of the polishing head.

Similarly, an elastic body is provided in the gap between the outer peripheral surface of the carrier and the inner peripheral surface of the retainer ring so as to allow a relative displacement in the up and down direction and connected to the elastic body. Even if the mouth is provided, it is obstructed by the rotation of the platen and the retainer ring. A sufficient amount of slurry is directly supplied between the material to be polished and the polishing pad, and the slurry is surrounded by the retainer and hardly flows out, so that the slurry can be efficiently used with a minimum amount of slurry. Polishing can be performed. The reslurry is evenly supplied to the polishing pad surface by the rotation of the polishing head itself.

Similarly, when a slurry cleaning liquid supply mechanism is provided, the slurry remaining in the supply port and in the gap between the outer peripheral surface of the carrier and the inner peripheral surface of the retainer ring is removed before the slurry is involved or deteriorated. It can be washed away with a washing liquid. Further, according to the polishing apparatus of the present invention, at least one of a gas and a slurry is sprayed on the surface of the polishing pad by the spraying device, and the liquid remaining on the polishing pad is flushed and removed. This eliminates the need for the slurry that had been supplied on the polishing pad to remove the liquid from the polishing pad in the past, or allows the slurry to flush the liquid on the polishing pad more efficiently than in the past. Therefore, the consumption of the slurry can be significantly reduced.

Claims

The scope of the claims

1. A polishing head for polishing a material to be polished by pressing the material to be polished while moving relatively to the polishing pad on the surface of the polishing pad stuck on a platen,

A carrier that holds one surface of the material to be polished on its lower surface,

An annular retainer ring, which is concentrically arranged on the outer peripheral side of the carrier and which abuts on the polishing pad during polishing and locks the outer periphery of the material to be polished held on the inner peripheral surface by the carrier. Have

A polishing head, wherein a liquid supply path for supplying a liquid is formed in a gap between an outer peripheral surface of the carrier and an inner peripheral surface of the retainer ring.

2. The polishing head according to claim 1, wherein the liquid supply path is at least one of a flow path A provided in the carrier and a flow path B provided in the retainer ring.

3. The polishing head according to claim 1, wherein the liquid supply path is connected to a slurry Z cleaning liquid supply mechanism that selectively supplies one of a slurry and a cleaning liquid.

4. The polishing method according to claim 2, wherein a groove A connected to the flow path A and supplied with the liquid from the flow path A is formed all around the outer peripheral surface of the carrier. Polished head.

5. A groove B connected to the flow path B and supplied with the liquid from the flow path B is formed in the entire circumference of the inner peripheral surface of the retainer ring. Polishing head as described in section.

6. The flow path A is communicated from the center of the upper surface of the carrier to a plurality of locations on the outer peripheral surface, 3. The polishing head according to claim 2, wherein the polishing head is formed substantially radially from the center to the outer peripheral side.

7. The polishing head according to claim 1, wherein the liquid supply path is annular, and has a diameter of 2 mm or more and 1 Omm or less.

8. An elastic body is provided in the gap between the outer peripheral surface of the carrier and the inner peripheral surface of the retainer ring to allow relative displacement in the upward and downward directions and to connect them.

Providing a supply port for supplying liquid to the gap in the elastic body,

The polishing head according to claim 1, wherein the liquid supply path is connected to the supply port.

9. At least one of an outer peripheral edge of the carrier and an inner peripheral edge of the retainer ring is provided at a portion facing the elastic body with a housing portion that forms a housing space between the other peripheral portion,

9. The polishing head according to claim 8, wherein the supply port is provided in the elastic body at a portion facing the storage space.

10. The polishing head according to claim 9, wherein the housing portion is provided along the entire periphery of the peripheral portion where the housing portion is provided.

1 1. A wall portion erected upward in a gap between the lower surface of the housing portion and a peripheral surface of a peripheral portion provided with the housing portion.

10. The polishing head according to claim 9, wherein a plurality of connection paths for connecting the housing portion and the peripheral surface are provided at a plurality of locations in a circumferential direction of the wall portion.

12. The polishing head according to claim 11, wherein an inclined surface is provided on a lower surface of the housing portion, the inclined surface being gradually inclined downward toward the peripheral surface.

13. A polishing method in which a material to be polished is pressed against a surface of a polishing pad stuck on a platen while being moved relatively to the polishing pad by a polishing head, thereby polishing the material to be polished. hand,

The polishing head according to claim 1, wherein the slurry is supplied from the liquid supply path to a gap between an outer peripheral surface of the carrier and an inner peripheral surface of the retainer ring. A polishing method for performing polishing.

14. A polishing apparatus that presses the material to be polished while pressing the material to be polished on the surface of the polishing pad stuck on the platen while relatively moving the polishing pad with the polishing head. So,

A polishing apparatus, comprising: a spray device for blowing at least one of a gas and a slurry on a surface of the polishing pad.

15. The spray device according to claim 14, wherein the spraying device has a nozzle for discharging the gas or the slurry, and a nozzle moving mechanism for moving the nozzle on the surface of the polishing pad. Polishing equipment.

16. The polishing apparatus according to claim 15, wherein the nozzle is connected to a slurry cleaning liquid supply mechanism that selectively supplies one of a slurry and a cleaning liquid.

17. A method for polishing a material to be polished using the polishing apparatus according to claim 14, wherein a gas or a slurry is blown onto the surface of the polishing pad by the spraying device. The method for polishing a material to be polished, comprising: supplying the slurry onto the polishing pad after the liquid is removed to polish the material to be polished.