JP2000233363A - Polishing device and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing device and a polishing method capable of preventing shortage of polishing abrasive liquid positioned between a polishing cloth and an object to be polished and used in polishing actually. SOLUTION: In a polishing device which has a turn table 5 on which a polishing cloth is affixed on its top face and a top ring 1 and polishes and flattens a semiconductor wafer and turns it into a mirror face by pressing the semiconductor wafer held by the top ring 1 while rotating the turn table and the top ring 1, respectively, against the polishing cloth by a predetermined force by supplying abrasive liquid onto the polishing cloth, a pressing ring 3 is arranged around the top ring 1 having a recessed part 1a storing the semiconductor wafer so as to move vertically and rotate for a shaft core of the pressing ring 3 itself, and a member having a plurality of curved faces is provided on a lower face of the pressing ring 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus and method for polishing a polishing object such as a semiconductor wafer in a flat and mirror-like manner, and more particularly to a polishing apparatus having a mechanism for controlling a polishing amount of a peripheral portion of the polishing object. Apparatus and method.

[0002]

2. Description of the Related Art In recent years, as the degree of integration of semiconductor devices has increased, circuit wiring has become finer, and the distance between wirings has become smaller. In particular, in the case of optical lithography having a line width of 0.5 μm or less, the allowable depth of focus becomes shallow, so that the image plane of the stepper needs to be flat. Therefore, it is necessary to planarize the surface of the semiconductor wafer. As one of the planarization methods, polishing is performed by a polishing apparatus.

Conventionally, this type of polishing apparatus has a turntable that forms a polishing surface by attaching a polishing cloth to an upper surface, and a top ring that holds an object to be polished with the surface to be polished facing the turntable. The object to be polished is pressed against the turntable with a constant pressure by a top ring while rotating them, and the surface to be polished of the object to be polished is polished to a flat and mirror surface while supplying an abrasive liquid.

In the above-described polishing apparatus, if the relative pressing force between the polishing object being polished and the polishing cloth is not uniform over the entire surface of the polishing object,
Under-polishing or over-polishing occurs depending on the pressing force of each part. Therefore, in the conventional polishing apparatus, as means for avoiding the above-mentioned uneven pressing force, an elastic mat such as polyurethane, which has elasticity, is attached to the semiconductor wafer holding surface of the top ring, and the object to be polished is held. Part, that is, the top ring can be tilted with respect to the surface of the polishing cloth, by pressing the peripheral part of the polishing part of the polishing cloth independently of the top ring and the object to be polished,
Prevention of a step between the polishing area of the polishing cloth and the periphery thereof is performed.

FIG. 6 is a diagram showing a main part of an example of a conventional polishing apparatus. The polishing apparatus supplies a polishing liquid Q to the polishing cloth 42, a rotating turntable 41 having a polishing cloth 42 affixed to an upper surface thereof, a top ring 45 for holding a semiconductor wafer 43 to be polished in a rotatable and pressable manner, and a polishing cloth 42. A polishing liquid supply nozzle 48 is provided. The top ring 45 is connected to a top ring shaft 49 and supported by an air cylinder (not shown) so as to be vertically movable.

The top ring 45 has an elastic mat 47 made of polyurethane or the like on the lower surface thereof.
7 is held in contact with the semiconductor wafer 43. Further, the top ring 45 is provided with a cylindrical guide ring 46 </ b> A on the outer peripheral edge so as to prevent the semiconductor wafer 43 from coming off the lower surface of the top ring 45 during polishing. The guide ring 46A is fixed to the top ring 45, and its lower end surface protrudes from the holding surface of the top ring 45, and forms a recess inside. As a result, the semiconductor wafer 43 to be polished is
Are held in the recesses, and do not jump out of the top ring due to frictional force with the polishing pad 42 during polishing.

The semiconductor wafer 43 is held under the elastic mat 47 on the lower surface of the top ring 45 and the turntable 4
A semiconductor wafer 43 on the polishing cloth 42 on the top ring 4
5, and the turntable 41 and the top ring 45 are rotated so that the polishing pad 42 and the semiconductor wafer 43 are moved relative to each other for polishing. At this time, the polishing liquid Q is supplied from the polishing liquid supply nozzle 48 onto the polishing pad 42. As the polishing liquid, for example, a suspension of abrasive particles composed of fine particles in an alkaline solution is used, and a semiconductor wafer is polished by a combined action of a chemical polishing action by alkali and a mechanical polishing action by abrasive grains.

FIG. 7 is an enlarged sectional view showing a state of the semiconductor wafer 43, the polishing cloth 42, and the elastic mat 47 during polishing by the polishing apparatus shown in FIG. As shown in FIG. 7, in a case where only the polishing target presses the polishing cloth, the periphery of the semiconductor wafer 43 as the polishing target is a boundary between contact and non-contact with the polishing cloth 42. At the same time, it is a boundary between contact and non-contact with the elastic mat 47. Therefore, the polishing pressure applied to the object to be polished becomes non-uniform at the periphery of the object to be polished, which is a boundary between them, and only the periphery of the object to be polished is polished much, resulting in a so-called “edge droop”. was there.

In order to prevent the edge of the semiconductor wafer described above, the present applicant has previously disclosed in Japanese Patent Application No. 8-54055 a polishing apparatus having a structure for pressing a polishing cloth positioned on the outer peripheral side of a semiconductor wafer. Has been proposed.

FIG. 8 is a diagram showing a main part of an example of a polishing apparatus proposed in Japanese Patent Application No. 8-54055. The top ring 45 is connected to a top ring shaft 66 via a ball 65. The pressing ring 46 is a key 58
The pressing ring 46 is vertically movable with respect to the top ring 45 and is rotatable integrally with the top ring 45. The pressing ring 46 is connected to a pressing ring air cylinder 62 via a shaft 61 and a bearing holder 60 holding a bearing 67. The press ring air cylinder 62 is fixed to the top ring head 59. A plurality (for example, three) of the pressure ring air cylinders 62 are evenly arranged on the circumference. The top ring air cylinder 63 and the pressure ring air cylinder 62 are connected to a compressed air source 64 via regulators R1 and R2, respectively.

By adjusting the air pressure supplied to the top ring air cylinder 63 by the regulator R1, the pressing force of the top ring 45 for pressing the semiconductor wafer 43 against the polishing cloth 42 on the turntable 41 can be adjusted. By adjusting the air pressure supplied to the press ring air cylinder 62 by the regulator R2, the press force of the press ring 46 pressing the polishing pad 42 can be adjusted. By appropriately adjusting the pressing force of the pressing ring 46 against the top ring 45, the distribution of the polishing pressure from the center portion of the semiconductor wafer to the peripheral portion, and further, from the outer peripheral portion of the pressing ring 46 outside the semiconductor wafer 43, becomes continuous. And become uniform. Therefore, the semiconductor wafer 43
It is possible to prevent excess or deficiency in the amount of polishing at the outer peripheral portion of the substrate.

[0012]

In the polishing apparatus previously proposed by the present applicant in Japanese Patent Application No. 8-54055, a pressing ring surrounds a top ring, and the pressing ring is used during polishing of an object to be polished. Since the polishing cloth is pressed downward, the inflow of the slurry-like polishing abrasive fluid supplied to the surface of the polishing cloth into the inside of the pressing ring is blocked by the pressing ring, and the gap between the polishing cloth and the polishing target is removed. However, there is a problem that the polishing liquid actually used for polishing is insufficient.

FIG. 9 is a schematic plan view showing the relationship among a turntable, a pressing ring, and a top ring in the prior art. As shown in FIG. 9, the abrasive liquid supplied onto the polishing pad 42 from the abrasive liquid supply nozzle 48 spreads downstream, and reaches the upstream side of the pressing ring 46. A region A where the polishing liquid is relatively easy to enter and a region B on both sides where the polishing liquid is hard to enter occur. In addition, since the top ring 45 is tiltably supported via a spherical bearing such as a ball, an excessive tilt of the top ring 45 causes the polishing surface of the polishing object to be partially supplied with no abrasive liquid. Will occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is intended to prevent a shortage of a polishing abrasive liquid which is located between a polishing cloth and a polishing object and is actually used for polishing. It is an object of the present invention to provide a polishing apparatus and a method for polishing.

[0015]

According to a first aspect of the present invention, there is provided a turntable having a polishing cloth stuck on an upper surface thereof, and a top ring. While supplying, the polishing object which is held by the top ring while rotating the turntable and the top ring is pressed against the polishing cloth with a predetermined force to polish the object to be polished, and is a flat and mirror-finished polishing apparatus. A member having a plurality of curved surfaces on the lower surface of the pressing ring, a pressing ring is disposed around a top ring having a concave portion for accommodating the object to be polished, the pressing ring being vertically movable and rotatable about its own axis. It is characterized by having been provided.

According to a second aspect of the present invention, there is provided a turntable having a polishing cloth adhered to an upper surface thereof, and a top ring, wherein the turntable and the top ring are respectively supplied while an abrasive liquid is supplied to the polishing cloth. In a polishing apparatus in which the object to be polished held by the top ring is rotated while being rotated and pressed against the polishing cloth with a predetermined force to polish the object to be polished and flattened and mirror-finished, the top ring is pressed against the top ring. A first pressing means for rotating the top ring with respect to its own axis, and a first rotating means for rotating the top ring with respect to its own axis. And a second pressing means for pressing the pressing ring.

Further, a third aspect of the present invention has a turntable and a top ring each having an abrasive cloth attached to an upper surface thereof,
While supplying the polishing liquid to the polishing cloth, the object to be polished held by the top ring is pressed against the polishing cloth with a predetermined force while rotating the turntable and the top ring, and the object to be polished is polished. In the polishing method for mirror polishing, a pressing ring is arranged around a top ring having a concave portion for accommodating the object to be polished, and the pressing ring is rotated by rotation of the turntable. The polishing object is polished while flowing the polishing liquid supplied to the polishing cloth into the pressing ring by a member having a plurality of curved surfaces provided on the lower surface of the polishing cloth.

According to the present invention, the press ring rotates around its own axis with the rotation of the turntable during polishing,
The abrasive fluid supplied onto the polishing pad by the plurality of curved surfaces provided on the lower surface of the pressing ring with this rotation can be positively guided inside the pressing ring on the upstream side of the object to be polished. Therefore, the shortage of the polishing liquid used for polishing can be eliminated, and the polishing of the object to be polished is smoothly performed under a sufficient polishing liquid.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing the overall configuration of the polishing apparatus, FIG. 2 is a perspective view showing a main part of FIG. 1, and FIG.

1 to 3, reference numeral 1 denotes a top ring, and the top ring 1 is a top ring main body 1A.
And a retainer ring 1B detachably fixed to an outer peripheral portion of the top ring main body 1A by bolts 31. The concave portion 1a for accommodating the semiconductor wafer 4 is formed by the lower surface of the top ring main body 1A and the retainer ring 1B. . The upper surface of the semiconductor wafer 4 is held by the lower surface of the top ring main body 1A, and the outer peripheral portion of the semiconductor wafer 4 is held by the retainer ring 1B. A press ring 3 is provided around the top ring main body 1A and the retainer ring 1B so as to be vertically movable.

An elastic mat 2 is adhered to the lower surface of the top ring 1. In addition, below the top ring 1,
A turntable 5 on which an abrasive cloth 6 is stuck is provided. A mounting flange 32 is fixed to the top ring main body 1A. A top ring shaft 8 is disposed above the top ring 1.
The drive shaft flange 34 is fixed to the lower end of the drive shaft. The ball bearing 7 is interposed between the mounting flange 32 and the drive shaft flange 34. Further, a space 33 is formed between the top ring main body 1A and the mounting flange 32, and a liquid such as vacuum, pressurized air, or water can be supplied to the space 33. The top ring main body 1A has a number of communication holes 35 communicating with the space 33 and opening on the lower surface. The elastic mat 2 also has an opening at a position facing the communication hole 35. Thus, the upper surface of the semiconductor wafer 4 can be suctioned by vacuum, and a liquid or pressurized air can be supplied to the upper surface of the semiconductor wafer 4.

The top ring shaft 8 is a top ring air cylinder 1 fixed to a top ring head 9.
The top ring air cylinder 10 moves the top ring shaft 8 up and down, and presses the semiconductor wafer 4 held on the lower end surface of the top ring 1 against the turntable 5.

The top ring shaft 8 is connected to a rotary cylinder 11 via a key (not shown), and the rotary cylinder 11 has a timing pulley 12 on its outer periphery. The timing pulley 12 is connected via a timing belt 13 to a timing pulley 15 provided on a top ring motor 14 fixed to the top ring head 9. Therefore, when the top ring motor 14 is rotationally driven, the rotary cylinder 11 and the top ring shaft 8 rotate integrally via the timing pulley 15, the timing belt 13, and the timing pulley 12, and the top ring 1 rotates. The top ring head 9 is supported by a top ring head shaft 16 fixedly supported by a frame (not shown).

At the lower end of the pressing ring 3 provided around the top ring 1, only the inner peripheral side protrudes downward to form a protruding portion 3 a, and only the lower end surface of the protruding portion 3 a is the polishing cloth 6. Is formed as a ring-shaped pressing surface 3b for pressing.
The radial width or thickness t of the pressing surface 3b is 2 mm to
It is set to 6 mm. On the outer peripheral side of the pressing surface 3b, as shown in FIG. 2, a cascade of a plurality of blades 3c is provided at a predetermined pitch along a circumferential direction. The plurality of wings 3c form a plurality of curved surfaces. The lower surface of the wing 3c is gradually inclined upward toward the outside, and
a extending from a to the outer peripheral end of the pressing ring 3;
The protruding height is set so that the lower surface of the blade 3c does not contact the polishing cloth 6 even if the pressing surface 3b contacts the polishing cloth 6.

FIGS. 4 (a) and 4 (b) are IV views of FIG. 2 and show the bottom surface of the pressing ring 3. FIG. FIG.
As shown in (a), the plurality of blades 3c arranged in the circumferential direction at a predetermined pitch are formed into a blade shape whose projected shape is curved along the rotation direction of the pressing ring 3. That is, with the rotation of the turntable 5, the pressing ring 3
The turntable 5 is driven by frictional force caused by contact with the polishing cloth 6.
Since the rotational force is applied from, the wing 3 c rotates by twisting, but the wing 3 c rotates by the rotation of the pressing ring 3.
The abrasive fluid Q supplied onto the polishing pad 6 is formed in an airfoil shape that can be rolled inward in the radial direction. Further, as shown in FIG. 2, the lower surface of the blade 3c becomes a tapered surface 3ct which is inclined upward toward the outside in the radial direction to facilitate holding the slurry in the polishing liquid by surface tension.
As shown in FIG. 4 (b), a plurality of grooves 3h extending in the radial direction of the pressing ring 3 are formed in the projecting portion 3a at equal intervals, and the slurry is further polished on the surface of the semiconductor wafer inside the retainer ring 1B. May be supplied.

As shown in FIG. 1, the pressure ring 3 is connected to a pressure ring air cylinder 22 via a shaft 28 and a bearing retainer 27 holding a bearing 26. The press ring air cylinder 22 is fixed to the top ring head 9. A plurality (for example, three) of the pressure ring air cylinders 22 are evenly arranged on the same circumference. That is, a bearing 26 is interposed between the pressing ring 3 and the air cylinder 22, and the pressing ring 3 is pressed against the polishing pad 6 by the air cylinder 22 but can rotate freely. . Further, the retainer ring 1B is made of a metal such as stainless steel, and a tapered surface 1Bt inclined inward in the radial direction is formed on the lower part on the outer peripheral part of the retainer ring 1B as shown in FIG. It is formed thinner than the side. On the other hand, a tapered surface 3t inclined inward in the radial direction is formed at a position corresponding to the tapered surface of the retainer ring 1B on the inner peripheral portion of the pressing ring 3,
The pressing surface 3b of the pressing ring 3 is made as close as possible to the peripheral portion of the semiconductor wafer 4 held by the top ring 1.

With the above-described structure of the retainer ring 1B and the pressing ring 3, the distance between the inner peripheral edge of the pressing surface 3b of the pressing ring 3 and the peripheral edge of the semiconductor wafer 4 can be shortened. The polishing pad 6 near the peripheral portion of the wafer 4 can be pressed. Therefore,
The peripheral portion of the semiconductor wafer 4 can be prevented from being overpolished.

Note that no means such as a key for transmitting the rotation of the top ring 1 to the pressing ring 3 is provided between the top ring 1 and the pressing ring 3. Therefore, during polishing, the top ring 1 is
, The pressing ring 3 becomes free, and the pressing ring 3 rotates around its own axis by the application of the rotational force accompanying the rotation of the turntable 5.

As shown in FIG. 1, the top ring air cylinder 10 and the pressure ring air cylinder 22 are connected to a compressed air source 24 via regulators R1 and R2, respectively. The pressure of the top ring 1 pressing the semiconductor wafer 4 against the polishing pad 6 can be adjusted by adjusting the air pressure supplied to the top ring air cylinder 10 by the regulator R1, and the pressure ring air can be adjusted by the regulator R2. By adjusting the air pressure supplied to the cylinder 22, the pressing force of the pressing ring 3 pressing the polishing pad 6 can be adjusted. A polishing liquid supply nozzle 25 is provided above the turntable 5, and the polishing liquid Q is supplied to the polishing cloth 6 on the turntable 5 by the polishing liquid supply nozzle 25.

In the polishing apparatus having the above structure, the semiconductor wafer 4 is held on the lower surface of the top ring 1, and the top ring air cylinder 10 is operated while the top ring 1 is rotated by driving the top ring motor 14. The top ring 1 is pressed toward the turntable 5, and the semiconductor wafer 4 is pressed against the polishing pad 6 on the upper surface of the rotating turntable 5. On the other hand, the abrasive liquid supply nozzle 25
, The polishing cloth Q is held by the polishing pad 6.

FIG. 5 is a schematic plan view showing the relationship among the top ring, the pressing ring, and the turntable. As shown in FIG. 5, the turntable 5 and the top ring 1 rotate in the same direction. And, with the rotation of the turntable 5,
The rotational force is applied from the turntable 5 by the frictional force due to the contact with the polishing cloth 6, and the pressing ring 3 rotates (freely rotates) about its own axis. With the rotation of the pressing ring 3, the polishing liquid Q supplied onto the polishing pad 6 is positively applied to the pressing ring 3 on the upstream side of the semiconductor wafer 4 by a plurality of blades 3 c provided on the lower surface of the pressing ring 3. Guided inside. That is, since there is a slight gap between the lower surface of the blade 3c and the polishing cloth 6, the polishing cloth 6 located on the lower surface of the blade 3c includes:
The polishing liquid Q is effectively held by the surface tension. And wing 3c
The inertial force generated by the relative rotational movement of the polishing pad 6 and the polishing pad 6 acts so as to wind the polishing liquid Q held by the polishing pad 6 into the inside of the pressing ring 3, and the polishing liquid Q is located on the upstream side of the semiconductor wafer 4. Flows into the inside of the pressing ring 3. Therefore, the semiconductor wafer 4 is polished in a state where a sufficient and uniform polishing liquid Q exists between the polishing surface (lower surface) and the polishing cloth 6.

Here, the top ring air cylinder 10
The semiconductor wafer 4 is polished by appropriately adjusting the pressing force of the pressing ring 3 against the polishing pad 6 by the pressing ring air cylinder 22 in accordance with the pressing force of the top ring 1 by the pressure ring. By the regulator R1 during polishing can change the pressing force F ₁ which the top ring 1 to press the semiconductor wafer 4 to the polishing cloth 6 on the turntable 5, the pressing force F ₂ which is pressure ring 3 presses the polishing cloth 6 by the regulator R2 Can be changed (see FIG. 1). Therefore, during polishing, the pressing force F ₂ which is pressure ring 3 presses the polishing cloth 6 can be changed depending on the pressing force F ₁ which the top ring 1 to press the semiconductor wafer 4 to the polishing cloth 6. Pressing force _{F 2} against the pressing force _{F 1}
Is appropriately adjusted, the distribution of the polishing pressure from the center portion of the semiconductor wafer 4 to the peripheral portion, and further to the outer peripheral portion of the pressing ring 3 outside the semiconductor wafer 4 becomes continuous and uniform. Therefore, it is possible to prevent the polishing amount at the peripheral portion of the semiconductor wafer 4 from being excessive or insufficient.

When it is desired to intentionally increase the polishing amount at the peripheral portion of the semiconductor wafer 4 from the inner side, or conversely, reduce the polishing amount, the pressing force F ₂ of the pressing ring 3 is changed to the pressing force F 1 of the top ring _1. , The amount of polishing of the peripheral portion of the semiconductor wafer 4 can be intentionally increased or decreased.

According to the present embodiment, during polishing of the semiconductor wafer 4, the abrasive liquid is positively guided inside the pressing ring 3 by the wings 3c provided on the lower surface of the pressing ring 3, thereby being used for polishing. Of grinding fluid can be eliminated. Therefore, polishing of the object to be polished is performed smoothly under a sufficient polishing liquid. Then, even in the case of the large-diameter semiconductor wafer 4, a sufficient amount of the polishing liquid is secured.

Further, according to the present embodiment, the retainer ring 1B and the pressing ring 3 can be made of the most suitable materials. Since the inner peripheral surface of the retainer ring 1B is in contact with the semiconductor wafer 4 and the lower end thereof is not in contact with the polishing pad 6, the retainer ring 1B can be selected from a material having a relatively soft surface by, for example, applying a resin coating to metal. If a hard material is used, the semiconductor wafer 4 may be damaged during polishing. Further, even if the retainer ring 1B and the pressing ring 3 come into contact with each other, the two contact each other via the resin coating, so that there is no contact between the metals, and the relative movement (vertical movement and rotational movement) between the pressing ring 3 and the retainer ring 1B. Is performed smoothly.

[0036]

As described above, according to the present invention,
A plurality of blades provided on the lower surface of the pressing ring which rotates with the polishing can positively guide the abrasive liquid to the inside of the pressing ring on the upstream side of the object to be polished. Therefore,
Insufficiency of the polishing liquid used for polishing can be eliminated, whereby the polishing of the object to be polished is smoothly performed under a sufficient polishing liquid.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an overall configuration of an embodiment of a polishing apparatus according to the present invention.

FIG. 2 is a perspective view showing a main part of FIG.

FIG. 3 is a view taken in the direction of the arrow III in FIG. 2;

4 is a view taken in the direction of the arrow IV in FIG. 2 and shows the bottom surface of the pressing ring.

FIG. 5 is a schematic plan view showing a relationship among a top ring, a pressing ring, and a turntable according to the present invention.

FIG. 6 is a diagram showing a main part of an example of a conventional polishing apparatus.

FIG. 7 is an enlarged cross-sectional view showing a state of a semiconductor wafer, a polishing cloth, and an elastic mat during polishing by the polishing apparatus shown in FIG. 6;

FIG. 8 is a diagram showing a main part of an example of a polishing apparatus previously proposed by the present applicant.

FIG. 9 is a schematic plan view showing a relationship between a turntable, a pressing ring, and a top ring in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Top ring 1a Recess 1A Top ring main body 1B Retainer ring 1Bt, 3t Tapered surface 2 Elastic mat 3 Press ring 3a Projection 3b Press surface 3c Blade 4 Semiconductor wafer 5 Turntable 6 Polishing cloth 7 Ball bearing 8 Top ring shaft 9 Top ring Head 10 Air cylinder for top ring 11 Rotating cylinder 12, 15 Timing pulley 13 Timing belt 14 Motor for top ring 16 Top ring head shaft 22 Air cylinder for press ring 24 Compressed air source 25 Abrasive liquid supply nozzle 26 Bearing 27 Bearing press 28 Shaft 31 Bolt 32 Mounting flange 33 Space 34 Drive shaft flange 35 Communication hole Q Polishing abrasive liquid R1, R2 Regulator

Claims (5)

[Claims] 1. A polishing machine having a turntable having a polishing cloth adhered to an upper surface thereof and a top ring, wherein the polishing table is held by the top ring while supplying the polishing liquid to the polishing cloth while rotating the turntable and the top ring, respectively. In a polishing apparatus for polishing an object to be polished by pressing the object against the polishing cloth with a predetermined force and flattening and polishing the object to be polished, a pressing ring is vertically moved around a top ring having a concave portion for accommodating the object to be polished. A polishing apparatus, comprising: a member having a plurality of curved surfaces provided on a lower surface of the pressing ring, the member being movable and rotatable about its own axis. 2. The polishing apparatus according to claim 1, wherein the plurality of curved surfaces form a blade, and the blade has an airfoil shape that allows a polishing abrasive to flow into an inside of a pressing ring. 3. The polishing apparatus according to claim 1, wherein a rotational force is applied to the pressing ring from a turntable by frictional force caused by contact with a polishing cloth. 4. A polishing machine having a turntable having a polishing cloth adhered to an upper surface thereof, and a top ring, wherein the polishing table is held by the top ring while rotating the turntable and the top ring while supplying an abrasive liquid to the polishing cloth. In a polishing apparatus for polishing an object to be polished by pressing the object against the polishing cloth with a predetermined force and flattening and polishing the surface of the object, the top ring has a first pressing means for pressing the top ring; A first rotating means for rotating the top ring with respect to its own axis; and a pressing ring which is rotatable on the outer periphery of the top ring independently of the top ring. And a second pressing means for pressing the pressing ring. 5. A polishing machine having a turntable having a polishing cloth adhered to an upper surface thereof and a top ring, wherein the polishing table is held by the top ring while supplying the polishing liquid to the polishing cloth while rotating the turntable and the top ring, respectively. In a polishing method of pressing an object against the polishing cloth with a predetermined force to polish the object to be polished and flattening and mirror-finishing, a pressing ring is arranged around a top ring having a concave portion for accommodating the object to be polished. Then, the press ring is rotated by the rotation of the turntable, and the polishing liquid supplied to the polishing cloth is supplied to the inside of the press ring by a member having a plurality of curved surfaces provided on the lower surface of the press ring along with the rotation. A polishing object is polished while flowing into the polishing apparatus.