CN116887947A - Polishing pad - Google Patents

Abstract

The present invention can suppress the influence on the polishing performance and prevent the reduction of the end point detection accuracy obtained by the end point detection window. The polishing pad 3 includes an end point detection window 12 through which the inspection light L1 passes, and a plurality of concentric annular grooves 11 are formed in the polishing surface 3A of the polishing pad 3. The surface of the end point detection window 12 is formed at the same height as the polishing surface 3A, and a plurality of annular grooves 11A formed at the same radial position as the position where the end point detection window 12 is formed in the annular grooves 11 are not formed on the surface of the end point detection window 12, but include end portions 11A in the vicinity of the end point detection window 12. Further, the end portions 11A of the plurality of annular grooves 11A formed at the same radial position as the end point detection window 12 are connected to the end portions 11A by the connecting grooves 13.

Description

Polishing pad

Technical Field

The present invention relates to a polishing pad, and more particularly, to a polishing pad including a transparent end point detection window for detecting an end point of polishing.

Background

Previously, the following polishing pads are known, namely: a polishing apparatus includes a transparent end point detection window for detecting an end point of polishing, and concentric annular grooves are formed in a polishing surface (for example, see patent document 1).

In the polishing pad of patent document 1, the surface of the end point detection window is formed at the same height as the polishing surface, and the annular groove is formed so as to intersect with the end point detection window (in particular, the structure of fig. 3).

As such a polishing pad, it is known to form the surface of the end point detection window at the same height as the polishing surface (for example, see patent literature 2).

Here, when polishing an object to be polished by using the polishing pad, a liquid slurry is supplied between the polishing pad and the object to be polished, but if polishing dust or the like generated by polishing enters between the end point detection window and the object to be polished together with the slurry, the inspection light transmitted through the end point detection window may be blocked by the polishing dust or the like, and the accuracy of end point detection may be lowered.

Accordingly, in patent document 2, a plurality of concentric annular grooves are formed in the polishing surface of the polishing pad, and an end portion is formed at a position close to the end point detection window with respect to the annular groove having the same radial position as the end point detection window, and a flat barrier region is formed around the end point detection window.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication 2016-182667

Patent document 2: japanese patent application laid-open No. 2010-536583

Disclosure of Invention

Problems to be solved by the invention

Here, the annular groove formed in the polishing pad has a function of holding slurry in the annular groove, but polishing dust or the like generated by polishing also enters the annular groove.

Therefore, in the case of the polishing pad of patent document 1, if polishing dust or the like enters the annular groove formed in the end point detection window, the polishing dust or the like may enter between the end point detection window and the object to be polished, and inspection light transmitted through the end point detection window may be blocked by the polishing dust or the like, thereby degrading the end point detection accuracy.

Here, in the case of the polishing pad of patent document 1, since the grooves are formed in the end point detection window, there is a possibility that the transmission amount of the inspection light is different between the annular groove and the portion other than the annular groove, but in order to prevent the inspection light from passing through the grooves formed in the end point detection window, the end point detection window must be increased, and thus the end point detection window may affect the polishing performance.

On the other hand, when polishing an object to be polished by the polishing pad, on the one hand, the polishing pad is rotated and on the other hand, so that in the annular groove in the polishing pad of patent document 2 at the same radial position as the end point detection window, polishing dust is accumulated at the end portion in the rear direction of rotation due to the rotation of the polishing pad.

Further, since the end of the annular groove is located forward in the rotation direction of the end point detection window, when the polishing dust is discharged from the end of the annular groove, the polishing dust may pass over the barrier region and enter between the end point detection window and the object to be polished, and the end point detection accuracy may be lowered. In other words, the structure of patent document 2 has the following problems: the effect of suppressing the degradation of the end point detection accuracy due to the polishing dust or the like is extremely limited.

In view of such problems, the present invention provides a polishing pad capable of suppressing the influence on polishing performance and preventing the reduction of the end point detection accuracy by an end point detection window, and also provides a polishing pad capable of reducing the entry of polishing scraps and the like between the end point detection window and an object to be polished as much as possible, preventing the reduction of the end point detection accuracy by the end point detection window, and suppressing the influence on polishing performance.

Technical means for solving the problems

In view of the above, the polishing pad of the invention according to claim 1 comprises: a polishing layer having a polishing surface for polishing an object to be polished; and a transparent end point detection window provided in the polishing layer for transmitting inspection light of an end point detection mechanism to detect an end point of polishing, wherein the polishing pad further includes a plurality of concentric annular grooves on a polishing surface of the polishing layer,

The surface of the end point detection window is formed at the same height as the polishing surface,

among the annular grooves, a plurality of annular grooves formed at the same radial position as the position at which the end point detection window is formed are formed, and the annular grooves are not formed on the surface of the end point detection window, but include end portions in the vicinity of the end point detection window,

the ends of the plurality of annular grooves formed at the same radial position as the end point detection window are connected to each other by connecting grooves.

The polishing pad of the invention according to claim 5 further comprises: a polishing layer having a polishing surface for polishing an object to be polished; and an end point detection window provided in the polishing layer and configured to transmit the inspection light irradiated from the end point detection means to detect an end point of the polishing process,

the polishing pad is characterized in that the polishing surface is relatively rotated with respect to the object to be polished, the object to be polished is polished while the slurry is interposed between the polishing surface and the object to be polished,

a barrier groove is provided in a direction intersecting the rotation direction at a position near the front and rear of the rotation direction of the polishing pad with respect to the end point detection window, and the barrier groove is provided in a tapered shape widening toward the object to be polished.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the invention of claim 1, with respect to the annular groove formed at the same radial position as the position where the end point detection window is formed, the end portions are connected to each other by the connecting groove, whereby the polishing powder moving to the end portion of the annular groove can be moved to the radially outer peripheral side by the connecting groove, and the polishing powder can be prevented from entering between the end point detection window and the object to be polished as much as possible.

Further, since the grooves are not formed in the end point detection window, the influence of the polishing dust can be reduced, and the transmission amount of the inspection light at all positions of the end point detection window can be made equal, so that the area of forming the end point detection window can be reduced as much as possible, and the influence of the end point detection window on the polishing can be reduced as much as possible.

Further, according to the invention of claim 5, when the polishing scraps in the slurry are collected in the barrier grooves provided on the front and rear sides of the polishing pad in the rotation direction with respect to the end point detection window, the barrier grooves are formed in the direction intersecting the rotation direction, and therefore the polishing scraps flowing into the barrier grooves are moved toward the peripheral side end portions of the barrier grooves by the centrifugal force caused by the rotation of the polishing pad.

In particular, since the polishing dust discharged from the end portion of the outer peripheral side of the barrier groove located forward in the rotational direction with respect to the end point detection window does not enter between the end point detection window and the object to be polished, the polishing dust entering between the end point detection window and the object to be polished can be reduced as much as possible, and the detection accuracy obtained by the end point detection window can be maintained.

Further, by forming the tapered shape in the barrier groove, excessive polishing of the object to be polished by the edge on the polishing surface side of the barrier groove can be prevented, and further deformation of the polishing surface due to friction (shear stress) between the end point detection window and the object to be polished, which is caused by the barrier groove suppressing the slurry entering between the end point detection window and the object to be polished, can be absorbed, and polishing unevenness can be suppressed.

Drawings

Fig. 1 is a perspective view of a polishing apparatus.

Fig. 2 is a cross-sectional view of the main part of fig. 1.

Fig. 3 is an enlarged plan view of the polishing pad of the first embodiment.

Fig. 4 is a diagram showing a process for manufacturing the polishing pad of fig. 3.

Fig. 5 is an enlarged plan view of a polishing pad of a second embodiment.

Fig. 6 is an enlarged plan view of a polishing pad of a third embodiment.

Fig. 7 is an enlarged plan view of a polishing pad of a fourth embodiment.

Fig. 8 is an enlarged plan view of a polishing pad of a fifth embodiment.

Fig. 9 is an enlarged plan view of a polishing pad of a sixth embodiment.

Fig. 10 is an enlarged plan view of a polishing pad of a seventh embodiment.

Fig. 11 is a perspective view of a polishing apparatus according to an eighth embodiment and a ninth embodiment.

Fig. 12 is a cross-sectional view of the polishing apparatus.

Fig. 13 is a plan view of a polishing pad.

Fig. 14 is an enlarged plan view showing the polishing pad in the vicinity of the end point detection window.

Fig. 15 is a cross-sectional view of the XV-XV portion of fig. 14.

Fig. 16 is a cross-sectional view showing another structure related to the barrier groove.

Fig. 17 is a diagram illustrating a state in which the barrier groove of the tapered shape 212a is not formed.

Fig. 18 is a diagram illustrating a method for manufacturing a polishing layer.

Fig. 19 is an enlarged plan view showing a polishing pad in the vicinity of an end point detection window according to the ninth embodiment.

Detailed Description

The present invention will be described below with reference to the illustrated embodiment, and in fig. 1 to 2, reference numeral 1 denotes a polishing apparatus, and the polishing apparatus 1 polishes a thin plate-shaped object 2 to be polished (for example, a semiconductor wafer) with a polishing pad 3. The polishing apparatus 1 can detect progress of polishing and end point of the end of polishing by irradiating the surface 2A to be polished of the object 2 with the inspection light L1 when polishing the object 2.

The polishing apparatus 1 includes: a polishing surface plate 4 positioned at the lower side and fixed with a polishing pad 3 on the upper surface; a holding platen 5 located above and holding the object 2 to be polished on the lower surface; a slurry supply mechanism 6 for supplying slurry S (polishing liquid) between the object 2 to be polished and the polishing pad 3; and an end point detection means 7 for detecting the progress of the polishing process and the end point of the process of the object 2 to be polished by using the inspection light L1.

The object 2 to be polished by the polishing apparatus 1 is a plate-like object such as glass, metal, or ceramic, in addition to an optical material, a silicon wafer, a glass substrate for liquid crystal, and a semiconductor substrate. The slurry S supplied by the slurry supply means 6 may be any suitable one known in the past depending on the object 2 to be polished and the required machining accuracy.

The polishing platen 4 and the holding platen 5 are each formed in a substantially disk shape, and are rotated in the arrow direction by a driving mechanism, not shown, and the holding platen 5 is provided so as to be movable up and down.

When polishing the object 2, the surface 2A (lower surface) of the object 2 is pressed against the polishing surface 3A of the polishing pad 3 by the holding platen 5 with a set pressure, and the slurry S is supplied from the slurry supply mechanism 6 between the surface 2A of the object 2 and the polishing surface 3A of the polishing pad 3.

A plurality of annular grooves 11 are formed on the polishing surface 3A of the polishing pad 3 at equal intervals in the radial direction around the center (rotation center) of the polishing pad 3 in concentric circles. The plurality of annular grooves 11 serve as slurry holding grooves for holding the slurry S, and the slurry S discharged from the slurry supply mechanism 6 flows into the plurality of annular grooves 11 and is supplied to the entire polishing surface 3A.

In addition, when polishing the workpiece 2, it is necessary to detect the progress of the polishing of the workpiece 2 and the end point of the end of the polishing. Accordingly, the polishing apparatus 1 includes: the end point detection means 7 irradiates the inspection light L1 from below to above, and detects the progress of polishing and the end point of the polishing based on the reflected light L2 from the surface 2A of the object 2 to be polished.

At a predetermined position of the polishing pad 3, a transparent end point detection window 12 is provided, through which the inspection light L1 passes and through which the reflected light L2 from the surface 2A of the object 2 to be polished passes.

The polishing pad 3 has a disk shape, and includes a polishing layer 3C located on the upper side and a supporting layer 3D (buffer layer) adhered to the lower surface of the polishing layer 3C with an adhesive, the end point detection window 12 is provided at a predetermined position of the polishing layer 3C, and a through hole 3Da for passing the inspection light L1 and the reflected light L2 from the object 2 is provided in the supporting layer 3D so as to be aligned with the position of the end point detection window 12.

The lower surface of the polishing layer 3C is adhered to the upper surface of the supporting layer 3D by an adhesive or a double-sided tape, and the lower surface (lower surface of the supporting layer 3D) of the polishing pad 3 including the polishing layer 3C and the supporting layer 3D integrally formed up and down is fixed to the upper surface of the polishing platen 4 by an adhesive or a double-sided tape.

The end point detection window 12 is formed of a transparent material that transmits the inspection light L1 and the reflected light L2, and the end point detection window 12 is fitted in a through hole formed in a predetermined position of the polishing layer 3C without any gap. The diameter of the end point detection window 12 in this embodiment is set to 12mm. In the present embodiment, the end point detection window 12 has a circular shape in plan view, but may have various shapes such as a rectangle, a square, a polygon, and an ellipse.

The upper surface of the end point detection window 12 is formed on the same surface as the polishing surface 3A, which is the upper surface of the polishing layer 3C, while the lower surface of the end point detection window 12 is also formed on the same surface as the lower surface of the polishing layer 3C.

As the end point detection means 7, a light emitting portion 7A for emitting the inspection light L1 upward and a light receiving portion 7B for receiving the reflected light L2 from the object 2 to be polished are provided at a position below the end point detection window 12 of the polishing pad 3 and the through hole 3Da of the support layer 3D in the polishing platen 4, and the end point detection means includes a control portion 7C for controlling the operations of these and detecting the progress of the polishing process and the end point of the polishing process.

In polishing the object 2, the inspection light L1 is irradiated upward from the light-emitting portion 7A of the end point detection mechanism 7, and the inspection light L1 is irradiated to the surface 2A of the object 2 through the transparent end point detection window 12. Then, the inspection light L1 is reflected downward by the polished surface 2A of the object 2, and the reflected light L2 is transmitted through the transparent end point detection window 12 and is detected by the light receiving unit 7B. The reflected light L2 detected by the light receiving unit 7B is transmitted to the control unit 7C.

The surface 2A of the workpiece 2 to be polished is gradually polished as the polishing process of the workpiece 2 proceeds, and the intensity of the reflected light L2 detected by the light receiving unit 7B changes. When the intensity or the like of the reflected light L2 detected by the light receiving unit 7B reaches a pre-registered intensity or the like, the control unit 7C determines that the surface 2A to be polished has reached the end point of polishing, and stops polishing. Then, the driving mechanism is stopped, so that the rotation of the polishing platen 4 and the holding platen 5 is stopped, and the supply of the slurry S from the slurry supply mechanism 6 is also stopped.

In this way, the inspection light L1 of the end point detection means 7 can be used to detect the end point of the polishing process when the polishing process of the object 2 is performed. Further, the structure of the end point detection mechanism 7 using the inspection light L1 is known.

As described above, the polishing surface 3A is formed with a plurality of annular grooves 11 concentrically. In this embodiment, the width of each annular groove 11 is set to 0.4mm, and the pitch between adjacent annular grooves 11 is set to 2.8mm. The depth of each annular groove 11 was set to 0.6mm.

When the concentric annular grooves 11 are formed in this manner, the polishing pad 3 of the present embodiment is provided with the end point detection window 12, and therefore, the plurality of annular grooves 11 in the annular grooves 11 are formed at the same radial position as the end point detection window 12, that is, at the position where the distance from the center of the annular groove 11 is equal to the end point detection window 12.

Fig. 3 is an enlarged plan view of the vicinity of the end point detection window 12, and in fig. 3, an annular groove 11A formed at the same radial position as the end point detection window 12 is not formed on the surface of the end point detection window 12, but has an end portion 11A in the vicinity of the end point detection window 12.

In contrast, the annular groove 11 at a radial position different from the end point detection window 12, that is, the annular groove 11 located on the large diameter side and the small diameter side in the radial direction with respect to the end point detection window 12 is formed in an endless shape without the end portion 11a.

The polishing pad 3 of the present embodiment is characterized in that the end portions 11A of the plurality of annular grooves 11A formed at the same radial position as the end point detection window 12 are connected to the end portions 11A by connecting grooves 13 formed in the substantially radial direction.

In particular, in the present embodiment, the connecting groove 13 is formed in a straight line in the radial direction by arranging the end 11A and the end 11A of the annular groove 11A at the same radial position as the end point detection window 12 in the radial direction.

Here, the width of the connecting groove 13 may be the same as the width of the annular groove 11A, or the width of the connecting groove 13 may be made narrower or wider according to the purpose of discharging the abrasive dust in the slurry S as described later.

The cross-sectional shape of the coupling groove 13 may be rectangular similarly to the annular groove 11A, but may be a tapered shape widening toward the object to be polished, such as a V-shape or a trapezoid shape, or may be a shape in which corners on the polishing surface 3A side of the inner wall of the coupling groove 13 formed vertically are chamfered. Particularly, when the connecting groove 13 is tapered like a V-shape or a trapezoid shape, burrs are less likely to be generated on the inner wall of the connecting groove 13, and slurry or polishing dust is less likely to remain in the connecting groove 13.

As described above, in the polishing pad 3 of the present embodiment, the end portions 11A of the plurality of annular grooves 11A formed at the same radial position as the end point detection window 12 are connected to the end portions 11A by the connecting grooves 13, so that it is possible to prevent the end point detection accuracy from being lowered due to polishing scraps generated during polishing of the object 2.

As described above, the polishing pad 3 of the present embodiment includes the plurality of annular grooves 11, and the annular grooves 11A hold the slurry S during polishing, thereby supplying a proper amount of slurry S between the object 2 to be polished and the polishing surface 3A of the polishing pad 3.

On the other hand, the polishing dust generated by polishing the object 2 also enters the annular groove 11A together with the slurry S, and if the polishing dust enters between the end point detection window 12 formed on one surface with the polishing surface 3A and the object 2, there is a possibility that the intensities of the inspection light L1 and the reflected light L2 transmitted through the end point detection window 12 decrease, and the end point detection accuracy decreases.

Therefore, in the polishing pad 3 of the present embodiment, the plurality of annular grooves 11A formed at the same radial position as the end point detection window 12 are not formed on the surface of the end point detection window 12, and the end portions 11A of the annular grooves 11A are connected to each other by the connecting grooves 13.

According to this configuration, since the groove is not formed in the end point detection window 12, polishing dust does not enter between the end point detection window 12 and the workpiece 2 from the groove, and the transmission amount of the inspection light L1 does not change in the groove and the portion other than the groove.

Then, by forming the connecting groove 13, the polishing scraps entering the annular groove 11A are discharged between the polishing surface 3A and the workpiece 2 through the connecting groove 13 when they move to the end 11A. At this time, since the polishing pad 3 rotates during polishing and centrifugal force acts on the radial outer peripheral side, the polishing dust entering the coupling groove 13 can be moved to the radial outer peripheral side and discharged.

In particular, since the coupling groove 13 is provided adjacent to the end point detection window 12, the entry between the end point detection window 12 and the object 2 to be polished can be reduced by discharging the polishing dust from the coupling groove 13, and the fluctuation in the intensities of the inspection light L1 and the reflected light L2 transmitted through the end point detection window 12 can be suppressed, thereby maintaining the accuracy of end point detection.

Next, an embodiment of a method for producing the polishing pad 3 configured as described above will be described with reference to fig. 4.

Specifically, a polyisocyanate and a curing agent, which are materials of the end point detection window 12, are first mixed, and the mixture is centrifugally defoamed, and then the mixture is poured into a cylindrical mold frame to be cured, thereby forming the cylindrical portion 102. Then, the cylindrical portion 102 is disposed at a predetermined position of the rectangular box-shaped mold frame 101 so that the axis thereof becomes the vertical direction (see fig. 4 (a)).

Then, a mixture 103 is prepared by mixing a polyisocyanate, a curing agent, and hollow fine particles, which are materials of the polishing layer 3C, and the mixture 103 is poured into the mold frame 101 and solidified (see fig. 4 (a)), thereby forming a block-shaped polyurethane polyurea resin molded body 104 (see fig. 4 (b)) which mimics the internal space of the mold frame 101. The polyurethane polyurea resin molded body 104 becomes a part of the polishing layer 3C described above.

Then, after the polyurethane-polyurea resin molded body 104 is removed from the mold frame 101, the portion of the polyurethane-polyurea resin molded body 104 where the cylindrical portion 102 is embedded is cut thin along the horizontal plane so as to have a desired thickness, and is cut out as a sheet-like member 107 (see fig. 4 (c)).

Then, the sheet member 107 is ground (polished) to be smooth from the viewpoints of thickness correction and formation (conspicuity) of fine irregularities as needed (see fig. 4 (c)).

Then, the plurality of annular grooves 11 are formed on the polishing surface 3A of the sheet member 107 by cutting, and at this time, the end portion 11A is formed in the vicinity of the end point detection window 12 with respect to the annular groove 11A located at the same radial position as the end point detection window 12, and the end portion 11A is connected to the end portion 11A by the connecting groove 13. As a result, the polishing layer 3C of the polishing pad 3 shown in fig. 2 and 3 is completed, and then a double-sided tape or the like is attached to the lower surface of the polishing layer 3C opposite to the polishing surface 3A, and the support layer 3D (buffer layer) having the through holes 3Da formed therein is adhered to the lower surface of the polishing layer 3C with an adhesive (see fig. 4D).

Finally, the whole is cut into a disk shape, and the polishing pad 3 is completed.

The polishing pad 3 thus manufactured is fixed to the upper surface 4A of the polishing platen 4 on its lower surface (lower surface of the support layer 3D) by a double-sided tape, an adhesive agent, or the like.

The present embodiment is a method of manufacturing the cylindrical portion 102, which is to be the end point detection window 12, in advance, but is not limited thereto. As another example, a desired polishing layer may be produced by flowing and solidifying a material constituting the end point detection window 12 into the polyurethane polyurea resin molded body 104 having the holes.

Specifically, a columnar extraction member is disposed at a predetermined position of the mold frame 101 so that the axis thereof becomes the vertical direction, and the polyisocyanate, the curing agent, and the hollow fine particles, which are materials of the polishing layer 3C, are mixed to prepare a mixture 103, and the mixture 103 is flowed into the mold frame 101 and solidified to form a polyurethane polyurea resin molded body 104.

Then, the columnar extraction member is extracted upward from the formed polyurethane polyurea resin molded body 104 to form a columnar bottomed hole, and a mixture of polyisocyanate and a curing agent, which are to be the material of the end point detection window 12, is flowed into the bottomed hole to be cured. The hardened mixture forms a transparent cylindrical portion 102 which is then the end point detection window 12.

Thus, the polyurethane polyurea resin molded body 104 having the cylindrical portion 102 buried therein without any gap is completed. After the step of cutting the sheet-like member from the polyurethane-polyurea resin molded body 104, the sheet-like member can be produced by the same method as described above.

The end point detection window 12 and the polishing layer 3C in this example are produced using a polyisocyanate and a curing agent, but a prepolymer produced in advance using a polyol or the like may be used instead of the polyisocyanate. Further, as the curing agent, known diols, polyols, diamines, polyamines can be used.

Further, the polishing layer 3C in this embodiment has a foam structure formed using hollow fine particles. As the hollow fine particles, for example, hollow fine particles of vinylidene chloride-acrylonitrile copolymer can be used. In addition, in order to kill the foaming structure, a chemical foaming agent such as water or an inert gas may be used alone or in combination with the hollow fine particles.

The polishing pad 3 according to the second to seventh embodiments shown in fig. 5 to 10 will be described below.

In the polishing pad 3 of the second embodiment shown in fig. 5, the annular groove 11A located at the same radial position as the end point detection window 12 is formed as an arcuate portion 13a at the connection portion between the annular groove 11A located on the outer circumferential side in the radial direction of the polishing pad 3 and the connection groove 13.

In contrast, in the polishing pad 3 of the third embodiment shown in fig. 6, the annular groove 11A located at the same radial position as the end point detection window 12 has an arc-shaped portion 13a at the connecting portion between the annular groove 11A located on the radially inner peripheral side of the polishing pad 3 and the connecting groove 13.

In the polishing pad 3 according to the fourth embodiment shown in fig. 7, the connecting grooves 13 having the straight portions in the second and third embodiments are generally formed of the arcuate portions 13a. The following structure may be used: the connecting groove 13 has an arcuate portion 13a formed on both radially inner and outer circumferential sides thereof, and is formed in a straight line.

By forming the arcuate portion 13a at the connection portion between the annular groove 11A and the connecting groove 13 in this manner, the slurry or the abrasive dust can be prevented from remaining at the connection portion between the connecting groove 13 and the annular groove 11A.

In the polishing pad 3 of the fifth and sixth embodiments shown in fig. 8 and 9, the connecting grooves 13 are extended to the annular grooves 11 adjacent to each other in the radial direction with respect to the plurality of annular grooves 11A formed at the same radial position as the end point detection window 12, with respect to the polishing pad 3 of the first embodiment.

Specifically, the endless annular grooves 11, in which the end portions 11a are not formed, are located radially outward and inward of the end point detection window 12, and the connecting grooves 13 of the present embodiment extend to the annular grooves 11 located radially outward and inward of the end point detection window 12.

The coupling groove 13 of the fifth embodiment is formed so as to widen radially outward of the polishing pad 3 with respect to the end point detection window 12, whereas the coupling groove of the sixth embodiment is formed so as to narrow radially outward of the polishing pad 3 with respect to the end point detection window 12.

Further, according to the connecting groove 13 of the fifth and sixth embodiments having the above-described structure, the abrasive dust entering the connecting groove 13 can be moved to the annular groove 11 adjacent in the radial direction with respect to the end point detection window 12.

In particular, the abrasive dust entering the connecting groove 13 is moved to the endless annular groove 11 on the side of the radius Fang Xiangwai by the centrifugal force caused by the rotation of the polishing pad 3, and the discharge of the abrasive dust to the polishing surface 3a can be suppressed.

In the fifth and sixth embodiments, the connecting grooves 13 are formed to the endless annular groove 11 adjacent to the end point detection window 12 on the radially outer and inner peripheral sides, but the connecting grooves 13 may be formed to extend to the outer peripheral edge of the polishing pad 3, for example.

Further, the connecting groove 13 may not extend to the annular groove 11 located radially inward of the end point detection window 12, among the connecting grooves 13. That is, since the centrifugal force due to the rotation of the polishing pad 3 acts on the radially outer side, the connecting groove 13 may be extended to the radially Fang Xiangwai peripheral side in order to move the polishing chips to the radially outer peripheral side.

In the polishing pad 3 of the seventh embodiment shown in fig. 10, the coupling groove 13 is formed in a ring shape along the outer peripheral edge of the end point detection window 12 with respect to the polishing pad 3 of the first to sixth embodiments.

Specifically, grooves are formed so as to surround the end point detection window 12, and the ends 11A of the plurality of annular grooves 11A formed at the same radial position as the end point detection window 12 are connected as the connecting grooves 13.

Even with the coupling groove 13 having such a structure, since the end portions 11A and the end portions 11A of the plurality of annular grooves 11A formed at the same radial position as the end point detection window 12 are connected in the substantially radial direction, the polishing dust entering the annular grooves 11A can be discharged through the coupling groove 13 by the centrifugal force.

In the above embodiments, the description has been given on the assumption that the center of the plurality of annular grooves 11 provided at the concentric circles coincides with the center of the polishing surface 3A, but the center of the annular groove 11 may be eccentric with respect to the center of the polishing surface 3A.

Next, the present invention will be described with reference to an eighth embodiment and a ninth embodiment, in which fig. 11 and 12 are a block diagram and a cross-sectional view of a polishing apparatus 201, respectively, and a thin plate-like object to be polished 202 (e.g., a semiconductor wafer) is polished by a polishing pad 203 having a disk shape.

The polishing apparatus 201 includes: a polishing platen 204 located on the lower side, and having a polishing pad 203 fixed to the upper surface; a holding platen 205 located above and holding the object 202 to be polished on the lower surface; a slurry supply mechanism 206 for supplying slurry S (polishing liquid) between the object 202 to be polished and the polishing pad 203; and an end point detection mechanism 207 for detecting the progress of the polishing process of the object 202.

The polishing target 202 may be a plate-like material such as glass, metal, or ceramic, in addition to an optical material, a silicon wafer, a glass substrate for liquid crystal, or a semiconductor substrate, and the slurry S supplied by the slurry supply mechanism 206 may be appropriately selected according to the polishing target 202.

The polishing platen 204 and the holding platen 205 have a substantially disk shape, and the polishing pad 203 and the workpiece 202 attached to these platens have a substantially disk shape. The polishing surface plate 204 and the holding surface plate 205 are rotatably provided by a driving mechanism, not shown, and the holding surface plate 205 revolves around the rotation center of the polishing surface plate 204.

In polishing the object 202, the holding platen 205 rotates while pressing the object 202 with a desired pressure against the polishing surface 203a of the polishing pad 203 held by the polishing platen 204, and the slurry supply mechanism 206 supplies the slurry S between the object 202 and the polishing pad 203 in this state, whereby the object 202 is polished by the polishing pad 203.

As shown in fig. 12, the end point detection means 207 is provided below the polishing surface plate 204, irradiates the inspection light L1 upward, receives the reflected light L2 reflected by the object 202 to be polished, and detects the progress of the polishing process and the end point of the completion of the polishing process based on the received reflected light L2.

A through hole 204a for passing the inspection light L1 and the reflected light L2 is provided at a predetermined position of the polishing platen 204, and a transparent end point detection window 208 is provided on the polishing pad 203 in alignment with the position of the through hole 204 a.

As shown in fig. 13, three end point detection windows 208 are provided at equal intervals at a desired radial position on the polishing pad 203, and in this embodiment, the diameter of the end point detection windows 208 is about 9mm.

In the present embodiment, the end point detection window 208 is circular, but may be, for example, rectangular, square, polygonal, elliptical, or the like. In the present embodiment, three end point detection windows 208 are provided at equal intervals at a desired radial position of the polishing pad 203, but the position is not limited to this, and at least one window may be provided.

During polishing of the object 202, the end point detection means 207 irradiates the inspection light L1 upward, the inspection light L1 passes through the transparent end point detection window 208 and is reflected downward from the surface of the object 202, and the reflected light L2 passes through the transparent end point detection window 208 and is received by the end point detection means 207.

Further, the polishing surface of the workpiece 202 is gradually polished as the polishing process of the workpiece 202 proceeds, and the end point detection means 207 detects a change in the intensity of the reflected light L2 or the like. If the intensity of the detected reflected light L2 or the like is a pre-registered intensity or the like, it is determined that the surface to be polished is the processing end point.

In addition, when a film is formed on the surface of the object 202 as in the case of a semiconductor substrate, the progress of the polishing process is detected by detecting a change in the film thickness formed on the surface of the object 202 during polishing by using interference of light.

At this time, the inspection light L1 incident on the object 202 to be polished is reflected at the surface of the film and at the interface between the film and the substrate, and thus an optical path difference is generated between the reflected light L2 reflected at the surface of the film and the reflected light L2 reflected at the interface between the film and the substrate, and a phase difference is generated between the two reflected lights L2.

When the film thickness of the object 202 to be polished is changed by polishing, the phase difference of the reflected light L2 is changed, and the progress of polishing or the end point of polishing can be detected based on the change in the phase difference.

As shown in fig. 13, the polishing pad 203 has three end point detection windows 208 provided at desired radial positions, a plurality of annular grooves 211 formed in concentric circles around the center (rotation center) of the polishing pad 203, and barrier grooves 212 provided at positions close to the end point detection windows 208 in front and rear directions of the rotation direction of the polishing pad 203.

Here, the polishing apparatus 201 of the present embodiment rotates the polishing pad 203 clockwise around the illustration of fig. 13. The rotation direction of the polishing pad 203 may be reversed, or the rotation direction may be reversed during the polishing operation.

Here, fig. 12 shows a portion where the cross-sectional view shown in the section XII to XII of fig. 13 is obtained, and the polishing pad 203 includes: a polishing layer 203A having a polishing surface 203A formed on the object 202 side; and a supporting layer 203B (buffer layer) formed on the polishing surface plate 204 side of the polishing layer 203A.

The polishing layer 203A includes a sheet having a foamed structure and including an elastic resin such as polyurethane and having a thickness of 0.8mm to 2.6 mm. By the foaming structure, open pores caused by the foaming structure can be formed on the grinding surface during grinding, and slurry is stored, so that the grinding efficiency is improved. More specifically, a foamed sheet containing an elastic resin such as polyurethane and having numerous voids formed therein in the range of from a submicron unit to several tens of microns can be used.

The support layer 203B may be a woven or nonwoven fabric impregnated with a resin such as polyurethane or the like, a resin foam such as polyurethane or the like, a resin sheet such as polyester or the like, or the like having a thickness of 0.1mm to 5.0mm, and in particular, if the support layer 203B having voids formed is a woven or nonwoven fabric impregnated with a resin such as polyurethane or the like, or a resin foam such as polyurethane or the like, it is preferable that the cushioning property against overpolishing is excellent.

The polishing layer 203A and the supporting layer 203B are bonded by an adhesive or a double-sided tape, and the lower surface of the supporting layer 203B is fixed to the upper surface of the polishing platen 204 by the adhesive or the double-sided tape.

The end point detection window 208 is made of a transparent material that transmits light, and may be made of an elastic resin such as polyurethane similar to the polishing layer 203A.

However, in order to allow the inspection light L1 and the reflected light L2 to pass through the end point detection window 208, it is necessary to avoid foaming that prevents light from passing through. Therefore, more specifically, an elastic resin body such as polyurethane having no voids formed therein can be preferably used.

The end point detection window 208 is fitted in a through hole formed in a predetermined position of the polishing layer 203A without any gap, and the upper and lower surfaces of the end point detection window 208 are formed on the same surface as the polishing surface 203A and the lower surface of the polishing layer 203A, respectively.

In particular, since the upper surface of the end point detection window 208 is disposed on the same surface as the polishing surface 203a, the end point detection window 208 is in contact with the object 202 to be polished during polishing, and thus the transmission of the inspection light L1 and the reflected light L2 is prevented from being hindered by the slurry.

Further, by setting the lower surface of the end point detection window 208 and the lower surface of the polishing layer 203A to be flush with each other, the lower surface of the polishing layer 203A can be used to a minimum even when the polishing pad 203 is worn by polishing. Conversely, if the lower surface of the end point detection window 208 protrudes further toward the support layer 203B than the lower surface of the polishing layer 203A, the initial thickness of the end point detection window 208 is too large, and the transmission of the inspection light L1 and the reflected light L2 is further blocked, which is not preferable.

In addition, a through hole 203Ba is formed in the support layer 203B so as to be aligned with the position of the end point detection window 208, and when the polishing pad 203 is mounted on the polishing platen 204, the end point detection window 208 and the through hole 203Ba are aligned with the position of the through hole 204a formed in the polishing platen 204.

As shown in fig. 13, the annular groove 211 is formed in a concentric circle around the rotation center of the polishing pad 203, and is formed in an endless shape except for an annular groove 211 formed at the same radial position as the end point detection window 208, which will be described later.

In this embodiment, the annular grooves 211 are each set to have a width of 0.4mm and a depth of 0.6mm, and the pitch between adjacent annular grooves 211 is set to 2.8mm.

The annular groove 211 formed at the same radial position as the end point detection window 208 is an end-shaped groove having an end at a position close to the end point detection window 208. The width or depth and the pitch may be the same as those of the endless annular groove 211.

Here, the annular groove 211 having the same radial position as the end point detection window 208 means that the annular groove 211 is formed at a position intersecting or interfering with the end point detection window 208 when the annular groove 211 is formed in an endless shape.

In the case where the annular groove 211 does not intersect the end point detection window 208, for example, the annular groove 211 located radially inward or outward of the end point detection window 208 may be formed so as to avoid the end point detection window 208 when a flat surface of a desired width cannot be secured between the annular groove 211 and the end point detection window 208, and the annular groove 211 may be regarded as an annular groove 211 having the same radial position as the end point detection window 208.

Fig. 14 is an enlarged view of the vicinity of the end point detection window 208 on the polishing surface 203a of the polishing pad 203. In fig. 14, the end point detection window 208 moves from the rear side in the rotation direction in the right direction to the front side in the rotation direction in the left direction in the drawing along with the rotation of the polishing pad 203.

The barrier groove 212 is formed in a direction crossing the rotation direction of the polishing pad 203, specifically, the barrier groove 212 is formed in a radial direction passing through the vicinity of the center of the polishing pad 203.

The barrier groove 212 is formed at a position close to the front and rear of the end point detection window 208 in the rotational direction, for example, at a position 3mm to 20mm, preferably 5mm to 10mm away from the end of the end point detection window 208.

By making the barrier groove 212 distant from the end of the end point detection window 208 by at least 3mm or more, the following can be suppressed: the end point detection window 208 is easily peeled from the polishing layer 203A due to a difference between the friction with the object 202 to be polished or a difference between the deformation and the end point detection window 208 during polishing of the polishing layer 203A. On the other hand, by providing the barrier groove 212 at a distance of 20mm or less from the end of the end point detection window 208, the slurry entering between the end point detection window 208 and the workpiece 202 can be suppressed from being interposed.

The barrier groove 212 is connected to an end portion of the annular groove 211 formed at the same radial position as the end point detection window 208, and both ends of the barrier groove 212 are formed to the positions of the annular groove 211 located at the outermost peripheral side and the innermost peripheral side of the annular groove 211 formed at the same radial position as the end point detection window 208.

Thus, a flat surface including the polishing surface 203a is formed around the end point detection window 208, in other words, no groove is formed at the end point detection window 208 and at a position close to the end point detection window 208.

Fig. 15 is a cross-sectional view of the XV-XV portion of the polishing layer 203A in fig. 14, and specifically, a cross-sectional view of the polishing layer 203A along the rotation direction of the polishing pad 203.

The width or depth of the barrier groove 212 is the same as the annular groove 211, but in the barrier groove 212 of the present embodiment, a tapered shape 212a is formed so as to widen toward the object 202 to be polished.

As the tapered shape 212a, a shape in which the corner on the polishing surface 203a side of the inner wall of the barrier groove 212 formed vertically is chamfered at 45 ° at a position of about 0.1mm in depth may be included as one inclined surface from the bottom surface of the barrier groove 212 toward the polishing surface 203a as shown in fig. 16.

Here, the chamfer angle of the tapered shape 212a with respect to the polishing surface 203a is preferably 30 ° to 80 °. By setting the angle to 30 ° or more, the polishing surface 203a is less likely to be affected by deformation due to friction, and by setting the angle to 80 ° or less, the edge effect can be suppressed. In particular, when the angle is 70 ° or less, the polishing surface 203a is less likely to be affected by deformation due to friction.

Further, if the depth of the chamfer of the tapered shape 212a is 0.1mm or more, the abrasive surface 203a is preferably less likely to be affected by deformation due to friction.

Here, the shape of the barrier groove 212 may be appropriately changed according to the purpose of discharging the polishing dust in the slurry S or the degree of deformation of the polishing layer 203A described later.

When polishing the object 202 by using the polishing pad 203 having the above-described structure, the slurry S is supplied between the object 202 and the polishing pad 203 as described above, and when the slurry S enters the annular groove 211 or the barrier groove 212, the slurry S is supplied between the object 202 and the polishing pad 203.

Here, the polishing pad 203 is rotated by the polishing platen 204, and the end point detection window 208 is moved from the right side to the left side in the drawing in fig. 15. Thus, the slurry S flows relatively from the front side (left side in the drawing) to the rear side (right side in the drawing) in the rotation direction with respect to the end point detection window 208.

Further, since the polishing scraps are generated when the object 202 is polished by the polishing pad 203, the scraps enter between the end point detection window 208 and the object 202 together with the slurry S from the front of the end point detection window 208.

Further, if polishing dust enters between the end point detection window 208 and the object 202 to be polished, the intensities of the inspection light L1 and the reflected light L2 transmitted through the end point detection window 208 may decrease, and the end point detection accuracy may decrease.

In contrast, the polishing pad 203 of the present embodiment includes the barrier grooves 212 at the front and rear sides of the end point detection window 208 in the rotation direction, respectively, and thus, as described below, the degradation of the end point detection accuracy is suppressed as much as possible.

As described above, the polishing dust flows from the front side of the end point detection window 208 in the rotation direction together with the slurry S, but the polishing dust is recovered by the barrier groove 212 provided at the front side of the end point detection window 208 in the rotation direction.

Further, since the barrier groove 212 is provided in a direction intersecting the rotation direction, the polishing dust moves to the outer peripheral side of the barrier groove 212 due to the centrifugal force caused by the rotation of the polishing pad 203, and is discharged from the end of the outer peripheral side of the barrier groove 212.

Since the polishing dust discharged from the end portion on the outer peripheral side of the barrier groove 212 is already discharged from the front side in the rotation direction of the end point detection window 208, the polishing dust can be prevented from entering between the end point detection window 208 and the object 202 to be polished as much as possible, and the degradation of the end point detection accuracy can be suppressed as much as possible.

Further, in the case of the present embodiment, the polishing powder also enters the annular groove 211 formed in the polishing surface 203a, but the polishing powder entering the annular groove 211 formed at the same radial position as the end point detection window 208 moves backward in the rotation direction along the annular groove 211 with the rotation of the polishing pad 203.

Further, the polishing grooves reaching the end portion of the annular groove 211 at the rear side in the rotation direction directly flow into the barrier groove 212 connected to the annular groove 211, and then are discharged from the end portion of the outer circumferential side of the barrier groove 212 as described above.

By connecting the end of the annular groove 211 formed at the same radial position as the end point detection window 208 to the barrier groove 212 in this manner, the polishing powder that has entered the annular groove 211 can be prevented from entering between the end point detection window 208 and the workpiece 202.

Next, the tapered shape 212a of the barrier groove 212 formed in the present embodiment will be described.

Fig. 17 is a cross-sectional view taken along the rotation direction of the polishing pad 203, similarly to fig. 15, but the barrier groove 212 shown in fig. 17 is omitted from the tapered shape 212a, and schematically shows a state when the polishing pad 203 rotates to polish the object 202 to be polished.

When the tapered shape 212a is not formed in the barrier groove 212, the sidewall constituting the barrier groove 212 is vertically contacted with the polishing object 202.

When the polishing pad 203 rotates in this state, the barrier groove 212 is provided in a direction intersecting the rotation direction, so that a so-called edge effect occurs in a contact portion with the sidewall of the barrier groove 212, particularly in a contact portion with the sidewall of the barrier groove 212 located at the rear side in the rotation direction, and there is a possibility that the workpiece 202 is excessively polished by the sidewall of the barrier groove 212, resulting in uneven polishing.

In contrast, in the polishing pad 203 of the present embodiment, since the tapered shape 212a is provided in the barrier groove 212 as shown in fig. 15, the occurrence of polishing unevenness due to the edge effect is prevented.

Further, since the polishing pad 203 of the present embodiment has the end point detection window 208 and the polishing surface 203a formed on one surface, the end point detection window 208 is in close contact with the object 202 to be polished, and thereby a larger friction force is generated between the end point detection window 208 and the object 202 than between the other polishing surface 203a and the object 202 to be polished.

In this case, it is considered that the polishing surface 203a has the openings of the foamed structure for storing the slurry S, whereas the end point detection window 208 has a structure in which the openings of the foamed structure are limited on the surface of the end point detection window 208 so as to allow the transmission of the inspection light L1 and the reflected light L2 and avoid the foaming that prevents the transmission of the light, and as a result, the area ratio of the contact with the object 202 to be polished is large, and the friction force is easily received.

Further, it is considered that the formation of the barrier groove 212 suppresses the intervention of the slurry S entering between the end point detection window 208 and the workpiece 202, and therefore the end point detection window 208 is likely to directly contact the workpiece 202, and a larger friction force (shear stress) is generated than in the portion between the polishing surface 203a and the workpiece 202.

As described above, since the end point detection window 208 is configured to avoid foaming, the end point detection window 208 is not easily deformed, and therefore when the polishing pad 203 rotates, the end point detection window 208 is pulled backward in the rotation direction by the friction force (shear stress), and the polishing layer 203A formed between the end point detection window 208 and the barrier groove 212 is deformed.

As a result, as shown in fig. 17, the polishing surface 203A of the deformed portion bulges due to the deformation of the polishing layer 203A with respect to the barrier groove 212 formed at the rear side in the rotation direction of the end point detection window 208, and thus polishing unevenness may occur.

Therefore, since the polishing pad 203 of the present embodiment has the tapered shape 212a in the barrier groove 212 as shown in fig. 15, the tapered shape 212a can absorb the deformation of the polishing layer 203A, thereby preventing uneven polishing.

Here, in the barrier groove 212 provided on the front and rear sides in the rotational direction with respect to the end point detection window 208, the tapered shape 212a formed on the front side of the barrier groove 212 on the rear side in the rotational direction with respect to the end point detection window 208 has an effect of preventing the occurrence of the polishing unevenness.

Therefore, the tapered shape 212a of the barrier groove 212 on the front side in the rotation direction with respect to the end point detection window 208, which is the front side in the rotation direction, may be omitted, but in view of rotating the polishing pad 203 in the opposite direction, it is desirable to provide the tapered shape 212a on both the front side and the rear side in the rotation direction of the barrier groove 212.

Next, an embodiment of a method for manufacturing the polishing pad 203 configured as described above will be described with reference to fig. 18.

First, a rectangular parallelepiped mold 301 is prepared, a columnar extraction member 302 is disposed at a predetermined position of the mold 301 so as to match the outer diameter of the end point detection window 208, and hollow fine particles of a polyisocyanate, a curing agent, and a vinylidene chloride-acrylonitrile copolymer for forming a foam structure, which are materials of the polishing layer 203A, are mixed, and the obtained mixture is flowed into the mold 301 to be cured (fig. 18 (a)). Thus, a block-shaped polyurethane polyurea-based resin molded foam 303 which then constitutes the polishing layer 203A is molded.

Then, the columnar extraction member 302 is extracted from the resin molded foam 303, a columnar space 302 'is formed in the resin molded foam 303, and a mixture of polyisocyanate and a curing agent, which are materials of the end point detection window 208, is optionally subjected to a defoaming treatment, and then flows into the columnar space 302' to be cured (fig. 18 (b)). Thereby forming a transparent cylindrical portion 304 which thereafter constitutes the end point detection window 208.

Then, the resin molded foam 303 and the columnar portion 304 are removed from the mold 301, cut to be thinner than the polishing layer 203A of the polishing pad 203, and cut as a sheet member 305 (fig. 18 (c)). At this time, the upper and lower surfaces of the end point detection window 208 are formed on the same surface as the upper and lower surfaces of the polishing layer 203A.

Finally, after the sheet member 305 is cut into a disk shape, the surface to be the polishing surface 203a is optionally ground (polished) from the viewpoints of thickness correction and formation of fine irregularities, the polishing surface 203a is cut to form the annular groove 211 and the barrier groove 212 (not shown), and the barrier groove 212 is cut to form the tapered shape 212a (not shown) (fig. 18 d).

The polishing layer 203A of the polishing pad 203 is thus obtained, and then the lower surface on the opposite side to the polishing surface 203A is attached to the supporting layer 203B (buffer layer) by a double-sided tape or the like, and the polishing pad 203 is completed.

In the present embodiment, the columnar portion 304 which is to be the end point detection window 208 is formed by flowing a material into the columnar space 302' formed in the resin molded foam 303, but the columnar portion 304 may be prepared in advance, and then placed in a predetermined position of the mold 301, and the material of the polishing layer 203A may be poured into the mold 301 and solidified.

In this embodiment, the polishing layer 203A and the end point detection window 208 use a polyisocyanate and a hardener, but the polyisocyanate may be an article prepared by preparing a prepolymer from a polyol or the like.

As the curing agent, a polyol or polyamine having a chain extension by polyisocyanate or the like may be used as long as it has a plurality of functional groups such as hydroxyl groups and amino groups which react with isocyanate.

Further, in this example, hollow fine particles of vinylidene chloride-acrylonitrile copolymer are used for forming a foam structure in the polishing layer 203A, but a chemical foaming agent such as water or an inert gas may be used alone or in combination.

Fig. 19 is a view illustrating the polishing pad 203 of the ninth embodiment, and is an enlarged plan view of the vicinity of the end point detection window 208 provided on the polishing surface 203a, as in fig. 14.

In this embodiment, the barrier groove 212 is connected to an endless annular groove 211 adjacent to the end point detection window 208 on the outer side and the inner side in the radial direction.

In the eighth embodiment, the following structure is provided: the annular groove 211 at the same radial position as the end point detection window 208 is formed as an end-shaped groove, and the end portions of the end-shaped annular groove 211 are connected to each other by the barrier groove 212, whereas in the present embodiment, the barrier groove 212 is further extended in the radial direction and connected to the end-free annular groove 211 located on the outer peripheral side and the inner peripheral side of the end point detection window 208.

With this configuration, the polishing scraps collected in the barrier groove 212 move along the barrier groove 212 toward the outer peripheral side due to the rotation of the polishing pad 203, and flow into the endless annular groove adjacent to the outer peripheral side of the end point detection window 208, so that the polishing scraps can be discharged from the front side in the rotation direction of the end point detection window 208 without flowing out to the polishing surface 203 a.

In the ninth embodiment, the barrier groove 212 is extended to the endless annular groove 211 adjacent to the end point detection window 208 on the outer side and the inner side in the radial direction, but may be extended to the annular groove on either the outer side or the inner side.

However, since the polishing scraps collected in the barrier groove 212 are directed radially outward by the centrifugal force of the polishing pad 203, it is preferable to connect the barrier groove 212 to the radially outward annular groove 211 in order not to flow out the polishing scraps to the polishing surface 203 a.

In the ninth embodiment, the barrier groove 212 is extended to the endless annular groove 211 provided at the position closest to the end point detection window 208, but the barrier groove 212 may be extended so as to intersect with a plurality of endless annular grooves 211. More specifically, the radially outer end of the barrier groove 212 may be extended to the outer peripheral edge of the polishing pad 203.

Further, in the above embodiments, the description has been given on the assumption that the center of the plurality of annular grooves 211 provided at the concentric circle coincides with the center of the polishing surface 203a, but the center of the annular groove 211 may be eccentric with respect to the center of the polishing surface 203 a.

Description of symbols

1. 201: grinding device

2. 202: object to be polished

3. 203: polishing pad

3C, 203A: polishing layer

7. 207: end point detection mechanism

11. 211: annular groove

11A: annular groove with same radius position as end point detection window

11a: end portion

12. 208: window for end point detection

13: connecting groove

L1: inspection light

212: barrier groove

212a: cone shape

Claims (7)

1. A polishing pad comprising: a polishing layer having a polishing surface for polishing an object to be polished; and a transparent end point detection window provided in the polishing layer for transmitting inspection light of an end point detection mechanism to detect an end point of polishing, wherein the polishing pad further includes a plurality of concentric annular grooves on a polishing surface of the polishing layer,

the surface of the end point detection window is formed at the same height as the polishing surface,

among the annular grooves, a plurality of annular grooves formed at the same radial position as the position at which the end point detection window is formed are formed, and the annular grooves are not formed on the surface of the end point detection window, but include end portions in the vicinity of the end point detection window,

the ends of the plurality of annular grooves formed at the same radial position as the end point detection window are connected to each other by connecting grooves.

2. The polishing pad according to claim 1, wherein the connecting groove is extended to an annular groove adjacent in a radial direction to a plurality of annular grooves formed at the same radial position as the end point detection window.

3. The polishing pad according to claim 1, wherein the coupling groove is formed along an outer peripheral edge of the end point detection window.

4. The polishing pad according to claim 1, wherein a connecting portion between an end portion of at least one of the annular grooves located on the outermost peripheral side or the innermost peripheral side in the radial direction and the connecting groove is formed in an arc shape, among the annular grooves formed at the same radial position as the end point detection window.

5. A polishing pad comprising: a polishing layer having a polishing surface for polishing an object to be polished; and an end point detection window provided in the polishing layer and configured to transmit the inspection light irradiated from the end point detection means to detect an end point of the polishing process,

the polishing pad is characterized in that the polishing surface is relatively rotated with respect to the object to be polished, the object to be polished is polished while the slurry is interposed between the polishing surface and the object to be polished,

a barrier groove is provided in a direction intersecting the rotation direction at a position approaching the front and rear of the rotation direction of the polishing pad with respect to the end point detection window, and the barrier groove is provided in a tapered shape widening toward the object to be polished.

6. The polishing pad of claim 5, wherein a plurality of concentric annular grooves are formed in the polishing surface,

among the annular grooves, an annular groove formed at the same radial position as the end point detection window is formed as an end-shaped groove having both ends connected to the barrier groove.

7. The polishing pad according to claim 6, wherein the barrier groove is extended to an endless annular groove adjacent to at least one of the radially outer side and the radially inner side of the end point detection window.