JP2000127024A - Polishing device and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing device capable of adjusting the height of a guide ring member at high precision and provide a polishing method. SOLUTION: This polishing device 20 has a guide ring 46 preventing the drop of a wafer 24 and presses the wafer 24 to an abrasive cloth 23 arranged to face the polished face of the wafer 24 for polishing. The polishing device 20 is provided with a recessed section provided integrally with a top ring 36 and protruded outward in the radial direction of the top ring 36, a load cell provided between the guide ring 46 and the recessed section to measure the pressure applied to the guide ring 46, a piezoelectric element provided between the guide ring 46 and the recessed section to adjust the protruded height of the guide ring 46 against the wafer 24, and a piezoelectric element controller 54 controlling the operation of the piezoelectric element based on the measured result by the load cell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polishing apparatus and a polishing method for polishing an object to be polished such as a semiconductor wafer.

[0002]

2. Description of the Related Art In a polishing process for flattening a surface of a semiconductor wafer used for a super LSI or the like, an element wiring tends to be miniaturized and multilayered with an increase in the integration degree of the LSI. In addition, planarization of the wiring film is essential. For this reason, the semiconductor wafer needs to be flattened with high precision, and in order to perform such flattening, polishing is performed by a CMP method.

When a semiconductor wafer is polished by the CMP method, a polishing apparatus 1 as shown in FIG. 5 is used. The polishing apparatus 1 includes a carrier 3 for holding a wafer 2, a drive motor 4 for rotating the carrier 3, and an air cylinder for pressing the carrier 3 and the drive motor 4 against a table 6 described below with a predetermined pressure. 5
A table 6 opposed to the carrier 3; a polishing cloth 7 provided on the upper surface of the table 6 and made of non-woven fabric or polyurethane foam; and a drive motor 8 for driving the table 6 to rotate.

A supply means 9 for supplying a polishing liquid comprising abrasive grains and a chemical is provided on the polishing upper surface side of the polishing surface. The carrier 3 is provided to face the upper surface of the table 6, and holds the wafer 2 on the surface facing the table 6. On the outer periphery of the wafer 2,
A guide ring 10 is provided to prevent the wafer 2 from coming off the carrier 3 during polishing.

[0005]

Here, the conventional guide ring 10 has been manufactured with a predetermined dimension (a projection dimension with respect to the polishing pad 7). Therefore, FIG.
As shown in FIG.
When the pressure is lower than that, the pressing force at the outer peripheral portion of the wafer 2 becomes higher than that at the central portion. Therefore, the wafer 2 after polishing is
Has a convex shape in which the outer peripheral portion is sagged.

On the contrary, as shown in FIG. 6B, when the height of the guide ring 10 is higher than that of the wafer 2, unlike the case of FIG. The flatness of 2 has a concave shape in which the outer peripheral portion is warped.

As described above, the guide ring 10 and the wafer 2
If the heights of the polished surfaces do not coincide with each other, the above-described problem occurs. However, since the height of the wafer 2 changes during the polishing process, as shown in FIG. It has been difficult to form a configuration that matches the height of the wafer 2. For example, Japanese Unexamined Patent Publication No.
In the invention disclosed in Japanese Patent No. 168964, a configuration in which the height of the guide ring is adjusted by compressed air is disclosed.
Since the polishing amount at P is several μm to several tens μm, the adjustment accuracy required by the guide ring adjustment mechanism is required to be 1 μm or less, and such high-precision control may be performed depending on adjustment by compressed air. This cannot be performed, and a difference in height occurs between the wafer 2 and the guide ring 10, which cannot be eliminated.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polishing apparatus and a polishing method capable of adjusting the height of a guide ring member with high accuracy. Things.

[0009]

According to a first aspect of the present invention, there is provided a guide ring member for preventing a workpiece held by a holding means from falling off. In a polishing apparatus that performs polishing by pressing against a polishing cloth attached to a table upper surface that is disposed to face a polishing surface of an object, the polishing device is provided integrally with the holding means, and is formed radially outward of the holding means. A guide ring holding portion, a pressure measuring means provided between the guide ring member and the guide ring holding portion for measuring a pressure applied to the guide ring member, and the guide ring member and the guide ring. Provided between the holding parts,
Position adjusting means for adjusting the projecting height of the guide ring member with respect to the object to be polished, and control means for controlling the operation of the position adjusting means based on the measurement result by the pressure measuring means. It is a polishing apparatus characterized by the following.

The invention according to claim 2 is the polishing apparatus according to claim 1, wherein the position adjusting means is a piezoelectric element. According to a third aspect of the present invention, the control of the position adjusting device by the control means adjusts the pressure by adjusting the protruding height of the guide ring member to be equal to the pressing force applied to the object to be polished. 3. The polishing apparatus according to claim 1, wherein the polishing apparatus is adjusted so as to be higher or lower in advance.

According to a fourth aspect of the present invention, the holding means includes:
The polishing apparatus according to any one of claims 1 to 3, wherein pressure is applied through a bellows.

According to a fifth aspect of the present invention, there is provided a holding means to which a rotational drive is transmitted by a rotating shaft, and a guide ring member for preventing the object to be polished held by the holding means from falling off. In a polishing apparatus which performs polishing by pressing against a polishing cloth attached to a table upper surface which is disposed opposite to a polishing surface of an object to be polished, the polishing device is provided integrally with the holding means, and is provided radially outward of the holding means. The formed guide ring holding portion, a pressure measuring means provided between the guide ring member and the guide ring holding portion and measuring a pressure applied to the guide ring member, and the guide ring member and the guide Position adjusting means provided between the ring holding portions to adjust the height of the guide ring member protruding from the object to be polished, and a measurement result by the pressure measuring means. Control means for controlling the operation of the position adjusting means, and restricting the movement of the holding means in the rotation direction, and freely guiding the movement of the object to be polished in the normal direction to the rotation. And a movement guide mechanism for transmitting a rotating force of the shaft to the holding means.

According to a sixth aspect of the present invention, the guide ring member is held by the guide ring holding portion by a parallel notch spring. It is a polishing apparatus.

According to a seventh aspect of the present invention, in place of the pressure measuring means, the parallel notch spring is provided with a strain detecting means for detecting a distortion of the parallel notch spring. A polishing apparatus according to any one of claims 1 to 6.

The invention according to an eighth aspect of the present invention has a guide ring member for preventing the object to be polished held by the holding means from falling off, and is arranged opposite to the polishing surface of the object to be polished and attached to the upper surface of the table. A polishing method for performing a polishing process by pressing against a polished cloth, a pressure measuring step of measuring a pressure acting on a guide ring member before or during the polishing process of the object to be polished; A position adjusting step of controlling and adjusting the protruding height of the guide ring member relative to the object to be polished before or during the polishing of the object based on the measurement result in the pressure measuring step. Polishing method.

According to a ninth aspect of the present invention, there is provided the polishing method according to the eighth aspect, wherein the protrusion height of the object to be polished in the position adjusting step is adjusted by a piezoelectric element.

As a result of taking the above-described measures, the following operation occurs. According to the first aspect of the present invention, the pressure applied to the guide ring member is detected by the pressure measurement unit, and based on the detection result, the protrusion height of the guide ring member is adjusted by the position adjustment unit by the control unit. . Therefore, the pressure applied to the guide ring before or during the polishing is appropriately controlled.

According to the second and ninth aspects of the present invention, the position adjusting means is a piezoelectric element, and the height of the object to be polished is adjusted by the piezoelectric element. According to the third aspect of the present invention, the control means controls the position adjusting means to adjust the height of the guide ring member to be equal to the polished surface of the object to be polished.

If the height of the guide ring member is intentionally adjusted so as to be higher or lower than the processing surface of the object to be polished, the shape of the processing surface is intentionally made concave or convex. This is preferable in that it can be formed.

According to the fourth aspect of the present invention, pressure is applied to the holding means via the bellows. Therefore, by increasing the diameter of the bellows, variation in pressure distribution generated on the polished surface of the object to be polished is obtained. To reduce.

According to the fifth aspect of the present invention, since the slide guide mechanism is provided, the slide guide mechanism is provided at a lower position, thereby reducing rotational vibration and vibration vibration of the object to be polished.

According to the sixth aspect of the present invention, since the guide ring member is held by the guide ring holding portion by the parallel notch spring, the guide ring member is prevented from coming off, and the guide ring slides. Gives restoring power.

According to the seventh aspect of the present invention, since the parallel notch spring is provided with the distortion detecting means for detecting the distortion of the parallel notch spring, it is provided to the guide ring member in the same manner as the above-mentioned pressure measuring means. Can measure pressure.

According to the eighth aspect of the present invention, by providing the pressure measuring step and the position adjusting step, the protrusion height of the guide ring member with respect to the object to be polished before and during the polishing of the object to be polished can be reduced. Adjust appropriately.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The polishing apparatus 20 shown in FIG. The rotary table 21 has an upper surface formed as a flat surface, and a rotary shaft 22 for rotating the rotary table 21 is integrally attached to the lower surface of the center of the diameter. The rotating shaft 22 is connected to a drive source (not shown), and thereby rotates the polishing pad 23 attached to the upper surface of the rotating table 21 to rotate the polishing pad 23. , The wafer 24) can be polished.

A work rotation driving device 30 having a diameter smaller than the diameter of the polishing cloth 23 is disposed above the polishing cloth 23. The work rotation drive device 30 has a drive source 32 such as a motor on one end side. The drive source 32 is provided with a support arm (not shown) to support the work rotation drive device 30 so as not to vibrate. In addition, a nozzle 3 for supplying a polishing liquid onto the polishing pad 23 is provided in the vicinity of the work rotation driving device 30.
1 is provided.

As shown in FIG. 2, the rotary head 34 is provided with a guide 35 having a cylindrical shape and a top ring 36 located inside. The guide body 35 is connected to the lower end of the rotating shaft 33 and is driven to rotate with the rotation of the rotating shaft 33.

The guide member 3 is provided inside the guide member 35.
The top ring 36 is provided so as to be able to advance and retreat only in the axial direction of the rotating shaft 33 with respect to the shaft 5. The top ring 36 is connected to a bottom wall surface 47a of the guide body 35 (in FIG. 2, the upper surface side of the guide body) via a bellows 37. Here, the bellows 37 is provided with a size substantially equal to or slightly larger than the diameter of the wafer 24. That is,
The configuration is such that a pressing force can be applied to the wafer 24 in a large area. Air is introduced into the inside of the bellows 37, whereby a predetermined pressing force is applied to the top ring 36. Further, a liquid may be circulated instead of air.

For this reason, the bellows 3 of the guide body 35
An insertion hole 38 is formed in the attachment portion 7, and an air supply path (not shown) is connected to the insertion hole 38. Note that the air supply path provided in communication with the insertion hole 38 may be formed inside the rotary shaft 33 or may be provided outside the rotary shaft 33.

The bellows 37 is provided with a pressure gauge 4 shown in FIG.
The pressure of the air supplied to the bellows 37 is measured by a pressure gauge 40, and the operation of the pressure supply device 41 is controlled based on the measurement result. I have.

A groove 42 is formed on the outer peripheral wall surface of the top ring 36 along the vertical direction.
The guide roller 43 is fitted in the second roller 2. The guide roller 43 is formed in a spherical body, and is fitted into a groove 44 formed on the inner peripheral wall surface of the guide body 35. Therefore, the guide ring 43 rolls the groove portions 42 and 44, so that the top ring 36 can be slid vertically with respect to the guide body 35. That is, these two groove portions 42 and 44 and the guide roller 43 constitute a sliding guide mechanism. Therefore, when the pressing force of the bellows 37 changes, the top ring 36 slides up and down. .

The guide rollers 4 are provided in both the groove portions 42 and 44.
When the top ring 36 is fitted, the relative position change in the rotation direction is regulated so that the top ring 36 follows the rotation of the guide body 35.

The guide roller 43 is positioned as low as possible with respect to the polishing surface of the wafer 24, for example, the wafer 2
4 is attached at a position of about 20 mm or less from the polishing surface. It is also possible to provide a plurality of guide rollers 43 for one groove, in which case the top ring 36
Of the rotating shaft 33 in the axial direction and the ability to regulate the relative position in the rotating direction are further improved.

The center of the lower surface of the top ring 36 is a wafer holding surface 45 for holding the wafer 24. The wafer holding surface 45 is flattened with high precision in order to hold the wafer 24 with high accuracy, and the wafer 24 is held on the wafer holding surface 45 by, for example, vacuum suction, bonding with wax, or a water-applied film. The wafer is held by various methods such as holding the wafer.

When the wafer 24 is held on the wafer holding surface 45 by vacuum suction, a large number of suction holes 46 are formed inside the top ring 36, and the wafer 24 is positioned on the wafer holding surface 45 so as to be excellent. It can be held by suction. At this time, the flatness of the top ring 36 can be directly transferred to the wafer 24, which can contribute to highly accurate polishing.

The wafer holding surface 45 of the top ring 36
A guide ring 46 is provided at a position closer to the outer periphery than the outer periphery of the wafer. The guide ring 46 is provided over the entire outer periphery of the wafer holding surface 45 to prevent the wafer 24 from shifting from the wafer holding surface 45 in the surface direction of the wafer holding surface 45.
Further, it has a function of relieving an excessive pressing force of the polishing pad 23 at the edge of the polished surface of the wafer 24. In order to position the guide ring 46 at the outer peripheral edge of the wafer, the top ring 36 is formed such that the wafer holding surface 45 is formed in a columnar shape and the outer peripheral side of the columnar shape is formed in a ring shape. A concave portion 47 is formed. That is, the outer peripheral side of the concave portion 47 is extended to the lower surface side so as to be in close proximity to the polishing pad 23 (or the rotary table 21) at the time of polishing the wafer 24. Is also configured not to protrude excessively. The guide ring 46 is disposed in the concave portion 47.

The guide ring and the top ring 36 are similar to the guide body 35 and the top ring 36 described above.
The guide roller 48 guides the reciprocation in the up-down direction and restricts a change in position in the rotation direction. Therefore, the wafer holding surface 45 of the top ring 36
On the outer peripheral wall surface and the inner peripheral wall surface of the guide ring 46,
Grooves 49, 50 are formed in each of the grooves 49, 50.
A guide roller 48 is fitted to 50.

A load cell 51 is provided on the bottom wall surface 47a of the concave portion 47. In addition, this load cell 5
A piezoelectric element 52 is provided at a position between 1 and the upper surface of the guide ring 46. For this reason, the guide ring 4
When a load is applied to the load cell 6, the load is directly applied to the load cell 51, and the load can be detected.

The load cell 51 is connected to a pressure gauge 53 (an amplifier and a controller of the load cell 51) provided outside the work rotation driving device 30 as shown in FIG. The load can be measured.

The piezoelectric element 52 is connected to a piezoelectric element controller 54 shown in FIG. The piezoelectric element controller 54 changes the voltage value applied to the piezoelectric element 52 according to the measurement result of the pressure gauge 53, and thereby changes the pressing force applied to the guide ring 46.

One end of a parallel notch spring 55 for applying a pressing force toward the center in the vertical and radial directions is attached to the outer peripheral wall surface of the guide ring 46. The other end of the parallel notch spring 55
It is attached to the inner wall surface of the concave portion 47. Thereby, the guide ring 46 is restrained by the parallel notch spring 55, and is prevented from coming off the concave portion 47. At the same time, the parallel notch spring 55 is configured to give a position restoring property by an elastic force in the normal direction of the wafer 24.

The operation of the polishing apparatus 20 having the above configuration will be described below. The wafer 24 is held on the wafer holding surface 45, the wafer 24 is brought into contact with the polishing pad 23, and the bellows 37 is filled with air to apply a predetermined pressing force to the wafer 24. In this case, the operation state of the pressure supply device 41 is adjusted by applying a pressure to the polishing process by measuring the pressure by the pressure gauge 40.

Here, when performing the polishing process, the height of the guide ring 46 is adjusted. When the height of the guide ring 46 is lower than the polished surface of the wafer 24, the pressure acting on the guide ring 46 is also low, and conversely, the guide ring 46
Is higher than the polished surface of the wafer 24, the pressure acting on the guide ring 46 increases. Therefore, whether or not the guide ring 46 is at the proper height is determined by the load cell 51.
And by measuring the pressure with the pressure gauge 53.

Specifically, when adjusting the height of the guide ring 46, the pressure is measured by the load cell 51 and the pressure gauge 53, and the measurement result is sent to the piezoelectric element controller 54. When the pressure is not an appropriate value, the piezoelectric element controller 54 is operated,
The piezoelectric element 52 is extended by increasing the voltage value applied to the piezoelectric element 52.

When the piezoelectric element 52 is extended, the load applied to the piezoelectric element 52 by the load cell 51 and the pressure gauge 53 is continuously measured, and the load is applied to the piezoelectric element 52 based on the measured value. By appropriately controlling the voltage value, the height of the guide ring 46 can always be kept in the same plane as the polished surface of the wafer 24. That is,
The voltage applied to the piezoelectric element 52 is controlled by the piezoelectric element controller 54 so that the pressure value measured by the load cell 51 and the pressure gauge 53 is always constant. As a result, the piezoelectric element 52 always applies a constant pressure to the guide ring 4.
6, and the protrusion height of the pressing surface of the guide ring 46 can be maintained at the same height as the height of the polished surface of the wafer 24. Of course, if desired by the user, it can be maintained at a position offset from the polished surface.

If the wafer 24 is polished in this state, even if the height of the wafer 24 changes due to polishing during the polishing, the height of the guide ring 46 follows the proper height. It is possible to do. That is, even if the wafer 24 is gradually thinned by the polishing process, the guide ring 46 can follow the sub-micron unit in accordance with the thinning of the wafer 24.

According to the polishing apparatus 20 having such a configuration, the pressure acting on the guide ring 46 is measured by the load cell 51 and the pressure gauge 53, and based on the measurement result, the piezoelectric element 5 is controlled by the piezoelectric element controller 54.
2 is controlled, the height of the pressing surface of the guide ring 46 is made equal to the height of the polished surface of the wafer 24 regardless of before and during the polishing process by controlling the voltage value. Thus, it is possible to prevent a step from occurring between them.

Therefore, the wafer 24 can be flattened and processed with high precision. In other words, it is possible to prevent edge curling of the wafer 24 and warpage of the outer peripheral portion of the wafer 24, which have been difficult to solve in the past. Flattening can be performed.

The height of the guide ring 46 is intentionally adjusted so as to be higher or lower than the polished surface of the wafer 24 so that the shape of the processed surface is intentionally formed into a concave or convex curved surface. It is also possible.

In the present invention, the protruding height of the guide ring 46 is adjusted by a voltage applied to the piezoelectric element 52, as compared with a configuration in which the protruding height of the guide ring 46 is mechanically adjusted by, for example, compressed air. Therefore, it is possible to cope with an adjustment accuracy of 1 μm or less required for height adjustment. Therefore, the adjustment accuracy of the flattening of the wafer 24 can be dramatically improved.

The guide body 35 and the top ring 3
6, a bellows 37 is provided.
Are provided with a diameter substantially the same as or larger than that of the wafer 24, so that a large pressing force can be applied to the polished surface of the wafer 24. For this reason, the variation in the pressure distribution on the polished surface can be reduced, and the processing of the wafer 24 having higher flatness can be performed.

Further, the guide ring 46 is restrained from coming off from the concave portion 47 by a parallel notch spring 55,
An elastic force is applied to the wafer 24 in the normal direction. Therefore, the guide ring 46 is prevented from coming off from the concave portion 47, and the guide ring 46 can be moved vertically with respect to the wafer 24.

The grooves 42 and 44 are formed, and the guide rollers 43 are fitted into the grooves 42 and 44. Therefore, the sliding of the top ring 36 in the rotation direction is restricted, and It is configured to be slidable in the normal direction (vertical direction). At the same time, since the guide roller 43 is mounted at a position as low as possible with respect to the polished surface of the wafer 24 (for example, approximately 20 mm or less), the influence of rotational vibration and vibration fluctuation on the polished surface of the wafer 24 is reduced. be able to. In addition, by providing it at a lower position, it is possible to reduce the influence of a rotational moment generated during polishing of the wafer 24.

Thus, the wafer 24 can be flattened and processed with higher precision. As mentioned above, although one Embodiment of this invention was described, this invention can be variously deformed besides this. This is described below.

In the above embodiment, the load cell 51 and the piezoelectric element 52 are provided. Instead of detecting the load by the load cell 51, as shown in FIGS. A configuration may be adopted in which the strain gauge 60 is attached to 55. In this case, a strain gauge 61 shown in FIG. 3 is electrically connected to the strain gauge 60, and the strain gauge 61 is further connected to the piezoelectric element controller 5.
4 is connected. For other configurations,
The configuration is the same as the configuration shown in FIGS. 1 and 2 described above.

Even in this case, the change in the position of the guide ring 46 can be detected well by measuring the distortion.
Since the strain is proportional to the stress, it is possible to obtain the same effect as in the case of the measurement by the load cell 51 described above. In addition, various modifications can be made without departing from the scope of the present invention.

[0057]

As described above, according to the present invention,
The pressure applied to the guide ring member is detected by the pressure measurement unit, and based on the detection result, the protruding height of the guide ring member is adjusted by the control unit by the position adjustment unit. Therefore, by appropriately controlling the pressure applied to the guide ring before the polishing process or during the polishing process, a step is generated between the polishing surface of the object to be polished and the pressing surface of the guide ring. Can be prevented.

For this reason, when the protrusion height of the pressing surface of the guide ring member is lower than the polishing surface of the object to be polished, the edge of the object to be polished or the protrusion height of the pressing surface of the guide ring member is reduced. It is possible to prevent the outer peripheral portion from being warped when it is higher than the polished surface of the object to be polished, and to supply the object to be polished that has been flattened with high precision.

[Brief description of the drawings]

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

FIG. 2 is a side sectional view showing a configuration near a rotary head of a workpiece rotation drive device of the polishing apparatus according to the embodiment;

FIG. 3 is a side view showing a configuration of a polishing apparatus according to a modification of the present invention.

FIG. 4 is a side sectional view showing a configuration near a rotary head of a workpiece rotation drive device of a polishing apparatus according to the modification.

FIG. 5 is a side view showing a configuration of a conventional polishing apparatus.

6A and 6B are diagrams showing a state when a wafer is polished using a conventional polishing apparatus, wherein FIG. 6A shows a case where a guide ring is lower than a wafer, FIG. 6B shows a case where the guide ring is higher than a wafer, (C) shows a case where the height of the guide ring and the wafer are equal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 ... Polishing device 21 ... Rotary table 23 ... Polishing cloth 24 ... Wafer 30 ... Work rotation drive device 33 ... Rotating shaft 35 ... Guide body 36 ... Top ring 37 ... Bellows 42, 44, 49, 50 ... Groove part 43, 48 ... Guide Roller 46 guide ring 47 concave part 51 load cell 52 piezoelectric element 53 pressure gauge 54 piezoelectric element controller 55 parallel notch spring 60 strain gauge

Claims (9)

[Claims] A guide ring member for preventing the object to be polished held by the holding means from falling off; and a guide ring member which is arranged to face the polishing surface of the object to be polished and is pressed against a polishing cloth attached to a table upper surface. A polishing device that is provided integrally with the holding means and is formed radially outward of the holding means; and a guide ring holding section between the guide ring member and the guide ring holding section. A pressure measuring means for measuring a pressure applied to the guide ring member; and a projection height of the guide ring member with respect to the object to be polished, also provided between the guide ring member and the guide ring holding portion. Position adjusting means for adjusting the position, and control means for controlling the operation of the position adjusting means based on the measurement result by the pressure measuring means. Polishing apparatus according to claim. 2. The polishing apparatus according to claim 1, wherein said position adjusting means is a piezoelectric element. 3. The control of the position adjusting device by the control means is performed by adjusting the pressure by adjusting the protrusion height of the guide ring member so as to be equal to the pressing force applied to the object to be polished. 3. The polishing apparatus according to claim 1, wherein the polishing apparatus is adjusted to be higher or lower. 4. A holding means to which pressure is applied via a bellows.
The polishing apparatus according to any one of the above. 5. A polished surface of an object to be polished, comprising a holding means to which rotation drive is transmitted by a rotating shaft, a guide ring member for preventing the object to be polished held from the holding means from falling off. A polishing apparatus that performs polishing by pressing against a polishing cloth attached to a table upper surface that is disposed opposite to the holding means, and is provided integrally with the holding means, and a guide ring holding formed radially outward of the holding means. A pressure measuring means provided between the guide ring member and the guide ring holding portion for measuring a pressure applied to the guide ring member; and between the guide ring member and the guide ring holding portion. Position adjusting means for adjusting the height of the guide ring member protruding from the object to be polished; and A control unit for controlling the operation of the adjusting unit; and a control unit that controls the movement of the holding unit in the rotation direction, and guides the movement of the object to be polished in the normal direction freely to reduce the rotation force of the rotation shaft. A polishing apparatus, comprising: a moving guide mechanism for transmitting the light to the holding means. 6. The polishing apparatus according to claim 1, wherein said guide ring member is held by said guide ring holding portion by a parallel notch spring. 7. A polishing apparatus according to claim 6, wherein said parallel notch spring is provided with a distortion detecting means for detecting a distortion of said parallel notch spring, in place of said pressure measuring means. . 8. A guide ring member for preventing the object to be polished held by the holding means from dropping off, and is pressed against a polishing cloth arranged opposite to the polishing surface of the object to be polished and attached to the upper surface of the table. In the polishing method for performing the polishing process, a pressure measuring step of measuring a pressure acting on the guide ring member before or during the polishing process of the object to be polished, and before or after the polishing process of the object to be polished A polishing process, comprising: controlling the position of the guide ring member with respect to the object to be polished during the polishing process based on the measurement result in the pressure measuring process. 9. The polishing method according to claim 8, wherein the protruding height of the object to be polished in the position adjusting step is adjusted by a piezoelectric element.