TW201446415A - Polishing pad and polishing method - Google Patents

Abstract

A polishing pad is provided, which inhibits decrease of a polishing rate and has a long lifetime by inhibiting clogging of a polishing surface. A polishing pad 7 includes a circular polishing surface 9, and a center is hollowed out into a circular ring shape. The polishing pad 7 includes a plurality of ring grooves 19 formed on the polishing surface 9. Each ring groove 19 is a perfect circle and disposed to be tangent with a periphery of the circular polishing surface 9. When a radius of the circle forming the polishing surface 9 is set as R, a radius of the circle of the hollowed center is set as r, and a diameter of the ring groove 19 is set as X, R-r ≤ X ≤ R is satisfied.

Description

Polishing pad and grinding method

The present invention relates to a polishing pad and a polishing method, and more particularly to a polishing pad used for polishing an object to be polished by a chemical mechanical polishing method and a polishing method using the same.

In the past, chemical mechanical polishing has been used as a method of polishing and planarizing the surface of a workpiece such as a semiconductor wafer, a glass substrate for a liquid crystal display, a glass substrate for a photomask, or a glass substrate for a disk. (Chemical Mechanical Polishing (CMP) method). When the object to be polished is polished by the CMP method, the polishing pad is pressed against the object to be polished, and the polishing pad and the object to be polished are rotated while supplying a slurry therebetween. The polishing liquid flows from the center side to the outside side by the centrifugal force accompanying the rotation of the polishing pad, and is finally discharged to the outside of the polishing pad. In addition, in order to achieve uniform and high-precision flattening of the object to be polished, it is possible to achieve uniform and high-precision planarization of the workpiece, and to suppress the consumption of the expensive polishing liquid and to efficiently discharge the scratch. For the purpose of grinding debris, a technique of forming grooves of various shapes on the polishing surface of the polishing pad is often used.

Further, as a polishing pad having a groove formed on its surface, the polishing pad described in Patent Document 1 is known.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-358653

However, in the polishing pad described in Patent Document 1, the direction in which the groove extends is closely related to the rotation direction of the polishing pad, and it is only possible to rotate in a specific one direction during polishing. Further, when the polishing pad is rotated in one direction at the time of polishing, the pile of the polishing surface of the polishing pad is tilted toward the downstream side in the rotation direction. Further, when the pile of the polishing surface is poured, the foamed opening portion on the surface of the polishing pad is likely to be blocked. Further, when the foamed opening portion is blocked, there is a problem that the holding ability of the filler in the polishing liquid is lowered and the polishing rate of the polishing pad is lowered.

Further, in order to eliminate the clogging of the polishing surface, it is necessary to perform conditioning to raise the pile surface of the polishing surface. However, in the polishing pad which is used to cause clogging, the frequency of the dressing is relatively high and the life of the polishing pad is relatively high. Shortening the problem.

Accordingly, the present invention has been made to solve the above problems, and an object thereof is to provide a polishing pad which can suppress a decrease in polishing rate of a polishing pad and has a long life by suppressing clogging of a polishing surface.

In order to solve the above problems, the present invention is a donut-shaped polishing pad including a circular polishing surface and having a central portion hollowed out in a circular shape, and the polishing pad is characterized in that The method includes a plurality of annular grooves formed on the polishing surface, each of the annular grooves being in a true circle and arranged to be tangent to a circumference of the circular polishing surface, and a circle forming the polishing surface When the radius is R, the radius of the circle of the hollowed-out central portion is r, and the diameter of the annular groove is X, the relationship of Rr≦X≦R is established. Or a circular polishing surface, comprising: a plurality of annular grooves formed on the polishing surface, each annular groove being rounded and arranged to be tangent to a circumference of the circular polishing surface; When the radius of the circle forming the polishing surface is R and the diameter of the annular groove is X, the relationship of X≦R is established, and the annular groove is tangent to or intersects with the adjacent annular groove.

According to the invention thus constituted, it is possible to provide a polishing pad having a plurality of annular grooves arranged in a perfect circle and tangential to the circumference of the circular polishing surface. Further, the annular groove of the polishing pad can preferably discharge and hold the polishing liquid even when the polishing pad is rotated in either direction. That is, the annular groove having a perfect circle includes two semi-annular grooves that are arranged in a line shape with respect to the radius of the circular surface of the polishing pad and that extend in an arc shape. Further, when the polishing pad having the two semi-annular grooves is rotated, since the one semi-annular groove has an arc toward the downstream side in the rotation direction, the polishing liquid can be dispersed in the center of the polishing pad and the side wall of the polishing pad. Since the other semi-annular groove assumes an arc toward the upstream side in the rotational direction, the polishing liquid that has reached the side wall of the polishing pad but has not been discharged can be returned to the center direction of the polishing pad. Further, when the polishing pad is rotated in the reverse direction, the other semi-annular groove presents an arc toward the downstream side in the rotation direction, and one semi-annular groove presents an arc toward the upstream side in the rotation direction, so that each semi-annular groove functions The opposite of the above situation. Therefore, the polishing pad of the present invention is whichever The direction rotation allows the slurry to be sufficiently dispersed. Thus, the polishing pad according to the present invention can exhibit high polishing performance without lowering the fluidity of the polishing liquid in any direction, thereby suppressing clogging caused by the polishing pad continuing to rotate in one direction. Further, the rotation direction is switched so that the polishing pad rotates in the reverse direction, whereby the pile which is tilted toward the downstream side in the rotation direction can be erected. Therefore, it is not necessary to perform trimming each time the direction of rotation is switched, so that the shortening of the life of the product due to the increase in the frequency of trimming can be suppressed.

Further, in the invention, it is preferable that the plurality of annular grooves have the same diameter, and the centers of the plurality of annular grooves are arranged concentrically with the circle forming the polishing surface, and are disposed in a circle having a diameter larger than the polishing surface. The diameter of the circle is short on the circumference.

According to the present invention thus constituted, the distance from the center of the annular groove to the center of the polishing surface forming the circle can be made the same in all the annular grooves. Thereby, the annular groove and the further semi-annular groove can be more uniformly arranged on the polishing surface, and the polishing liquid can be more uniformly dispersed on the polishing surface.

Further, in the invention, it is preferable that the plurality of annular grooves are arranged to be line symmetrical with respect to a diameter of a circle forming the polishing surface.

According to the present invention thus constituted, the annular groove and the semi-annular groove can be uniformly disposed on the polishing surface, and the polishing liquid can be more uniformly dispersed on the polishing surface.

In these cases, it is preferable that the plurality of annular grooves have three to six annular grooves.

According to the invention thus constituted, the polishing liquid can be sufficiently dispersed by setting the number of the annular grooves to at least three. Moreover, by at most the number of annular grooves In the case of 16 pieces, it is possible to suppress an increase in the density of the grooves in the vicinity of the center of the polishing pad, and the polishing liquid is retained, and the intersection of the annular grooves in which the polishing liquid is likely to remain can be reduced.

As described above, according to the present invention, it is possible to provide a polishing pad which can suppress a decrease in the polishing rate of the polishing pad and which has a long life by suppressing clogging of the polishing surface.

1‧‧‧Two-side grinding device

3‧‧‧Abrased objects

5‧‧‧grinding platen

7‧‧‧ polishing pad

9‧‧‧Grinding surface

13‧‧‧ Keeper

15‧‧‧Axis

19‧‧‧ annular groove

19a, 19b‧‧‧ semi-annular groove

21‧‧‧ fluff

A, B‧‧ arrows

C‧‧‧Center of the grinding surface

r‧‧‧The radius of the circle at the center of the hollowed out

R‧‧‧The radius of the circle forming the abrasive surface

X‧‧‧ diameter of the annular groove

Fig. 1 is a cross-sectional view showing a double-side polishing apparatus to which a polishing pad according to an embodiment of the present invention is applied.

Fig. 2 is a plan view of the polishing pad according to the embodiment of the present invention as seen from the side of the polishing surface.

Fig. 3 is an enlarged view of a region III of Fig. 2.

Fig. 4 is a plan view of the polishing pad according to the embodiment of the present invention as seen from the side of the polishing surface.

Fig. 5 is a plan view of the polishing pad according to the embodiment of the present invention as seen from the side of the polishing surface.

(a) and (b) of FIG. 6 are plan views of a polishing pad according to a modification of the embodiment of the present invention as seen from the side of the polishing surface.

7(a) and 7(b) are plan views of a polishing pad according to a modification of the embodiment of the present invention as seen from the side of the polishing surface.

Fig. 8 is a graph showing a change in the polishing rate of the polishing pad of the examples and the comparative examples of the present invention.

Fig. 9 is a graph showing the average value and standard deviation of the polishing rates of the polishing pads of the examples and comparative examples of the present invention.

Hereinafter, a polishing pad according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a cross-sectional view showing a double-side polishing apparatus to which a polishing pad according to an embodiment of the present invention is applied.

First, as shown in FIG. 1, the double-sided polishing apparatus 1 planarizes the surface of the to-be-polished material 3 by the CMP method. The double-sided polishing apparatus 1 includes a pair of polishing platens 5 that rotate about a rotation axis, a polishing pad 7 fixed to the upper surface of the polishing platen 5, and a holder 13 for holding the workpiece 3. The double-side polishing apparatus 1 is provided with polishing pads 7 on the surfaces of the opposing polishing presses 5, and the workpieces 3 are placed between the opposing polishing pads 7.

In the double-side polishing apparatus 1, the polishing liquid is supplied from the polishing liquid supply device (not shown) to the vicinity of the center of the polishing surface 9 of the polishing pad 7, and the polishing platen 5 is rotated about the shaft 15, and the holder 13 is rotated. Rotating around the center, the surface of the workpiece 3 held by the holder 13 in contact with the polishing pad 7 is flattened, and the polishing platen 5 is made of metal and has a disk shape. One side of the polishing platen 5 constitutes an attachment surface to which the polishing pad 7 is attached, and the attachment surface is substantially flat. A pair of grinding platens 5 are fixed to a shaft 15 passing through the center thereof, and are rotated about the shaft 15 by rotating the shaft 15.

The holder 13 has a larger diameter than the workpiece 3, and is configured by attaching a retaining pad made of, for example, a soft plastic to a hard platen. On the outer circumference of the platen, a gear that meshes with a gear of the outer circumference of the shaft 15 is formed, and the platen revolves around the center of the platen while revolving around the shaft 15 by rotating the shaft 15.

The polishing pad 7 is a pad made of a rigid polyurethane, for example, comprising a compound containing a polyisocyanate group. The prepolymer is produced by a dry process in which the prepolymer is hardened and formed by the reaction of a hardener, and has numerous bubbles inside. This bubble is opened toward the polishing surface 9 of the polishing pad 7. Further, the polishing pad 7 has an annular shape having substantially the same outer diameter as that of the polishing platen 5. Further, an annular surface of the annular polishing pad 7 constitutes the polishing surface 9. Further, the polishing pad 7 is detachably attached to the polishing platen 5. Further, the polishing pad 7 attached to the pair of polishing press plates 5 has the same configuration.

Fig. 2 is a plan view of the polishing pad as viewed from the side of the polishing surface. A plurality of annular grooves 19 are formed in the polishing surface 9 of the polishing pad 7. The annular groove 19 is a groove that extends in a ring shape when the polishing pad 7 is viewed from the polishing surface side. The annular groove 19 is formed to hold and disperse the polishing liquid when the polishing pad is rotated in the direction of the arrow A or the direction of the arrow B. The annular groove 19 extends in a perfect circle and is positioned such that its diameter reaches the outer periphery from the vicinity of the center of the polishing surface 9. As the cross-sectional shape of the annular groove 19, any known cross-sectional shape such as a V shape, a rectangular shape, or a semicircular shape can be employed.

Each of the plurality of annular grooves 19 has the same diameter and is disposed to surround the center of the polishing surface 9, and in the example shown in FIG. 2, a polishing pad in which three annular grooves 19 are arranged at equal angular intervals is shown. 7. The number of the annular grooves 19 can be appropriately selected in the range of 3 to 16, preferably 4 to 8. This is because if the number of the annular grooves 19 is too small, the polishing liquid cannot be sufficiently spread over the entire surface of the polishing surface 9. On the other hand, if the number of the annular grooves 19 is too large, it is near the center of the polishing surface 9. The density of the grooves is increased, or the number of intersections between the annular grooves 19 is increased, so that the fluidity of the polishing liquid is lowered to easily stay. Further, it is preferable that the plurality of annular grooves 19 are arranged in line symmetry with respect to a certain diameter of a circle forming the polishing surface 9. In this way, research can be made The distribution of the grooves on the grinding surface 9 and the distribution of the polishing liquid are more uniform.

The dimension of the length X of the diameter of the ring of the plurality of annular grooves 19 is defined such that the relationship between the radius R of the polishing surface 9 and the radius r of the hollowed-out circle and the relationship R-r≦X≦R is established. Further, the center of the plurality of annular grooves 19 is positioned on the circumference of a circle concentric with the circle forming the polishing surface 9. Thereby, the distance from the center of all the annular grooves 19 to the center of the rounded polishing surface 9 is the same, and the annular groove 19 can be regularly arranged. Further, the radius of the annular groove 19 is preferably set such that the adjacent annular grooves 19 are tangential to each other or intersect at two points. The adjacent annular grooves 19 are tangential to each other or intersect at two points, whereby the annular grooves 19 are connected to each other to improve the fluidity of the polishing liquid. Here, the adjacent annular grooves 19 are tangential to each other, meaning that the center lines of the adjacent annular grooves 19 are tangential or substantially tangent to each other, whereby the annular grooves 19 communicate with each other.

Fig. 3 is an enlarged view of a region III of Fig. 2. As shown in FIG. 3, the annular groove 19 is arranged to be tangent to the circumference of the polishing surface 9 on which the circle is formed. Here, the annular groove 19 is tangent to the circumference of the grinding surface 9 forming the circle, meaning that the center line of the annular groove 19 is tangent or substantially tangent to the circumference of the polishing surface 9, whereby the annular groove 19 is on the polishing pad. The side surface of the opening 7 is opened toward the outer side in the radial direction of the polishing pad 7.

Further, as shown in Fig. 2, by making the annular groove 19 a true circle, the annular groove 19 can be regarded as substantially consisting of a semi-annular groove 19a having a central angle of π and a semi-annular groove 19b. The semi-annular groove 19a and the semi-annular groove 19b are arranged in line symmetry with respect to the radius of the polishing surface 9 passing through the annular groove 19. Each of the semi-annular grooves 19a and the semi-annular grooves 19b extends from the vicinity of the center of the polishing surface 9 to the outer periphery, and is opened to the peripheral wall of the polishing pad 7. Further, when the polishing pad 7 is rotated in the direction of the arrow A, the semi-annular groove 19a is positioned. When the arc is formed on the downstream side in the rotational direction and toward the downstream side in the rotational direction, the polishing liquid is dispersed. On the contrary, when the polishing pad 7 is rotated in the direction of the arrow B, the semi-annular groove 19a is located on the upstream side in the rotational direction and is oriented. The upstream side of the rotation direction assumes an arc, and thus has a function of returning the polishing liquid to the center. On the other hand, when the polishing pad 7 is rotated in the direction of the arrow A, the semi-annular groove 19b is located on the upstream side in the rotational direction and presents an arc toward the upstream side in the rotational direction, and thus has a function of returning the polishing liquid to the center direction. When the polishing pad 7 is rotated in the direction of the arrow A, the semi-annular groove 19b is located on the downstream side in the rotational direction and presents an arc toward the downstream side in the rotational direction, and thus has a function of dispersing the polishing liquid.

Next, the action of the polishing pad 7 of the present embodiment will be described in detail. Fig. 4 is a plan view of the polishing pad of the embodiment as seen from the side of the polishing surface.

When the workpiece 3 is polished, first, as shown in FIG. 1, the polishing pad 7 is attached to each of the pair of polishing presses 5. Then, the surface of the polishing pad 7 is trimmed using a dresser, and then a pair of workpieces 3 into which the holder 13 is inserted is set between the pair of polishing platens 5 and the polishing pad 7. Next, the polishing platen 5 is rotated while supplying the polishing liquid to the polishing surface 9 of the polishing pad 7.

As shown in FIG. 4, when the polishing object 3 is polished while rotating the polishing pad 7 in the direction of the arrow A, the polishing liquid dropped from the polishing liquid supply device to the vicinity of the center of the polishing surface 9 is transferred to the polishing surface by centrifugal force. 9 is diffused in the radial direction. Further, most of the polishing liquid flows into the annular groove 19 and flows between the workpiece 3 and the polishing surface 9. The polishing liquid that has flowed into the annular groove 19 flows into the semi-annular groove 19a that is circular toward the downstream side in the rotational direction, and is along the semi-annular groove 19a by centrifugal force. It flows to the outer diameter direction of the polishing surface 9. Then, when the polishing liquid reaches the end portion of the semi-annular groove 19a, that is, the portion that is open to the peripheral wall of the polishing pad 7, a part of the polishing liquid is discharged in the radial direction of the polishing surface 9, and the remaining polishing liquid enters the upstream direction in the rotation direction. Inside the semi-annular groove 19b on the side. Then, the polishing liquid that has entered the semi-annular groove 19b returns to the center direction of the polishing surface 9 along the semi-annular groove 19b by centrifugal force. As described above, by forming the annular groove 19 on the polishing surface 9, the polishing liquid can be appropriately held and appropriately discharged.

When the polishing pad 7 is rotated in the direction of the arrow A and polishing is continued, the fluff 21 of the polyurethane 9 of the polishing surface 9 is tilted toward the upstream side in the rotational direction by the friction between the polishing surface 9 and the workpiece 3 . Therefore, the foamed opening portion of the polishing surface of the polishing pad 7 is blocked and clogging is likely to occur.

Therefore, after a certain degree of polishing, before the clogging is caused, as shown in FIG. 5, the rotation direction of the polishing pad 7 is switched to the rotation in the direction of the arrow B.

When the polishing pad 7 is rotated in the direction of the arrow B, the polishing liquid that has flowed into the annular groove 19 flows into the semi-annular groove 19b that is circular toward the downstream side in the rotational direction, and flows toward the polishing along the semi-annular groove 19b. The outer diameter direction of the face 9. Then, when the polishing liquid reaches the end portion of the semi-annular groove 19b, a part of the polishing liquid is discharged in the radial direction of the polishing surface 9, and the remaining polishing liquid enters the semi-annular groove 19a located on the upstream side in the rotational direction. Then, the polishing liquid that has entered the semi-annular groove 19a returns to the center direction of the polishing surface 9 along the semi-annular groove 19a.

Further, if the polishing pad 7 is rotated in the direction of the arrow B, the grinding is continued. In the grinding, the pile 21 which is poured by the friction of the polishing surface 9 and the workpiece 3 is raised. Therefore, when the rotation direction of the polishing pad 7 is switched, it is no longer necessary to perform trimming to raise the pile 21, or even if trimming is performed, it is only necessary to perform trimming for a short period of time. When the polishing pad 7 is continuously rotated in the direction of the arrow B, the pile 21 of the polyurethane of the polishing surface 9 is tilted toward the upstream side in the rotational direction. In this case, before the clogging is caused, the rotation direction of the polishing pad 7 is switched again to rotate the polishing pad 7 in the direction of the arrow A.

Even if the polishing pad 7 is rotated in either of the arrow A direction or the arrow B direction as described above, the polishing can be performed without causing clogging. In the polishing surface 9 of the polishing pad 7, the semi-annular groove 19a and the semi-annular groove 19b having a line shape with respect to the radius of the polishing surface 9 are formed, so that clogging is less likely to occur, and as a result, a decrease in the polishing rate can be suppressed. Further, since the polishing pad 7 has the annular groove 19 which is a perfect circle, the maintenance performance and the dispersion performance of the polishing liquid are not lowered even if the rotation direction is switched. Therefore, according to the polishing pad 7 of the present embodiment, the fluidity of the polishing liquid can be maintained regardless of which direction is rotated, and thus the occurrence of scratches can be suppressed.

Further, the polishing pad of the present embodiment can appropriately suppress the discharge amount of the polishing liquid regardless of the direction in which the polishing pad is rotated. Therefore, it is possible to suppress the consumption of the expensive polishing liquid.

Next, a modification of the above embodiment will be described.

6(a), 6(b), and 7(a) and 7(b) are plan views of the polishing pad of the modification as seen from the polishing surface side. In addition, for the convenience of description, the same reference numerals as those of the above-described embodiment are attached to the polishing pad, the polishing surface, and the annular groove.

As shown in FIG. 6( a ), the diameter of the three annular grooves 19 may be the same as the diameter of the polishing surface 9 , and the annular groove 19 may be disposed so as to intersect the center C of the polishing surface 9 . Shaped groove 19. Further, the number of the annular grooves 19 is not limited to three, and four or four or more annular grooves 19 may be provided as shown in Fig. 6(b). In the above case, the relationship between the diameter X of the annular groove 19 and the radius R of the circle forming the polishing surface 9 is established.

Further, as shown in FIG. 7(a), the plurality of annular grooves 19 can be positioned to be tangent to the inner circumference and the outer circumference of the polishing surface 9. In this case, all of the annular grooves 19 are opened in the center C direction of the polishing surface 9 at one position, and are opened in the radial direction of the polishing surface 9 at one position. Further, as shown in FIG. 7(b), one end of all the annular grooves 19 may be positioned so as to overlap at the center C of the polishing surface 9, and then the vicinity of the center may be hollowed out to form the polishing pad 7. In this case, all of the annular grooves 19 are opened in the center C direction of the polishing surface 9 at two locations, and are opened in the radial direction of the polishing surface 9 at one location. In the above case, the relationship between R-r≦X≦R is also established between the radius R of the circle forming the polishing surface 9 and the diameter X of the annular groove 19 and the radius r of the circle at the center portion of the hollowed out portion.

In addition, the present invention is not limited to the above-described embodiment and its modifications, and the respective configurations of the above-described embodiments and their modifications can be appropriately changed.

In particular, the number of annular grooves can be appropriately selected. For example, three grooves can be provided in the annular polishing pad 7 shown in Figs. 7(a) and 7(b), and can also be applied to Figs. 2 and 6 ( a) The polishing pad of the circular plate shown in Fig. 6(b) or the like is provided with eight grooves.

Further, in the above embodiment, the polishing pad is applied to the two-sided grinding. An example of a grinding apparatus is described in detail, but the polishing pad of the present invention can also be applied to a single-sided polishing apparatus.

Hereinafter, examples and comparative examples of the present invention will be described in detail.

In the examples and comparative examples, the polishing pads shown in Table 1 were prepared, and the surface of the silicon wafer was polished using the prepared polishing pad.

As a polishing apparatus, a double-sided polishing apparatus manufactured by Fujitsu Machinery Co., Ltd. was used, and as a polishing liquid, a colloidal silica type of FUJIMI INCORPORATED Co., Ltd. was used.

At the time of polishing, the polishing pressure was set to 150 g/cm ^{2 ,} and the crucible wafer having a diameter of 300 mm was pressed against the polishing pad while holding the platen, and the polishing pad was rotated in one direction while rotating the polishing pad around the center. At the time of polishing, the surface of the polishing pad is trimmed by a dresser, and then the polishing pad is rotated in the opposite direction to the rotation direction of the silicon wafer (hereinafter referred to as "reverse rotation direction"), and one batch is sequentially polished ( 5 矽 wafers), the rotation direction of the polishing pad is switched without trimming, and the polishing pad is rotated in the same direction (hereinafter referred to as "positive rotation direction") of the 矽 wafer, while grinding the next batch . Then, polishing of a total of 10 batches of tantalum wafer was performed for each polishing pad.

Next, the tantalum wafer was polished under the same conditions for all the polishing pads of the examples and the comparative examples 1 to 3, and the thickness of the germanium wafer was measured using Nanometoro 300TT-A manufactured by Kuroda Seiko Co., Ltd., and the polishing rate was calculated.

Fig. 8 shows changes in the polishing rates of the polishing pads of the examples and Comparative Examples 1 to 3, and Fig. 9 shows the average value of the polishing rates and the standard deviation thereof.

As shown in FIG. 8, in the polishing rate of the polishing pad of the embodiment, even if the two directions of the reverse rotation direction and the positive rotation direction are alternately rotated, the polishing rate is hardly changed. On the other hand, in the polishing pads of Comparative Examples 1 to 3, the polishing rate was drastically changed every time the rotation direction was switched.

Moreover, the standard deviation of the polishing rate of the polishing pad of the example is lower than that of the comparative example 1 to the standard deviation of the polishing rate of Comparative Example 3. Therefore, it is understood that the change in the polishing rate of the polishing pad of the example is smaller than the change in the polishing rate of the polishing pads of Comparative Examples 1 to 3.

7‧‧‧ polishing pad

9‧‧‧Grinding surface

19‧‧‧ annular groove

19a, 19b‧‧‧ semi-annular groove

A, B‧‧ arrows

r‧‧‧The radius of the circle at the center of the hollowed out

R‧‧‧The radius of the circle forming the abrasive surface

X‧‧‧ diameter of the annular groove

Claims (6)

A polishing pad is an annular polishing pad including a circular polishing surface and hollowed out at a central portion, and the polishing pad includes a plurality of annular grooves formed on the polishing surface, each ring-shaped The groove is formed in a perfect circle and is arranged to be tangent to the circumference of the circular polishing surface. The radius of the circle forming the polishing surface is R, and the radius of the circle at the center portion of the hollowed out is r, and the ring shape is When the diameter of the groove is X, the relationship of Rr ≦ X ≦ R is established. A polishing pad comprising a circular abrasive surface, comprising: a plurality of annular grooves formed on the polishing surface, each annular groove being rounded and disposed to be tangent to a circumference of the circular polishing surface; When the radius of the circle forming the polishing surface is R and the diameter of the annular groove is X, the relationship of X≦R is established, and the annular groove is tangential or intersects with the adjacent annular groove. The polishing pad according to claim 1 or 2, wherein the plurality of annular grooves have the same diameter, and the centers of the plurality of annular grooves are respectively arranged concentrically with a circle forming the polishing surface, and It is disposed on the circumference of a circle having a diameter shorter than the diameter of a circle forming the abrasive surface. The polishing pad according to any one of claims 1 to 3, The plurality of annular grooves are disposed in line symmetry with respect to a diameter of a circle forming the polishing surface. The polishing pad according to any one of claims 1 to 4, wherein the plurality of annular grooves have 3 to 16 annular grooves. A polishing method for polishing an object to be polished using the polishing pad according to any one of claims 1 to 5, characterized by comprising the step of: mounting the polishing pad on the polishing a device for trimming the surface of the polishing pad by a trimmer; supplying the polishing liquid from the polishing device to the polishing surface of the polishing pad; pressing the polishing pad against the object to be polished and rotating in a predetermined direction; and following the rotation After the step, the polishing pad is rotated in the opposite direction to the opposite direction of the rotation direction.