CN1577758A - Polishing pad, polishing apparatus and method for polishing wafer - Google Patents

Abstract

A polishing apparatus includes a belt-type surface plate stretched between two rollers each having a rotation shaft arranged in parallel to that of the other roller, a plurality of sheet-type polishing pads stuck on the surface plate, and a dresser for activating the polishing pads. Part of an upper end portion of each of the polishing pads facing an adjacent one of the polishing pads has an obtuse angle. Thus, the dresser is not caught by the upper end portion of each of the polishing pads, so that the generation of a scratch in the polishing pads. Therefore, a semiconductor wafer can be polished without causing a scratch thereon.

Description

Polishing pad, polishing device and method for polishing wafer

technical field

The invention relates to a wafer polishing method, a polishing device and the polishing device using the polishing pad, in particular to a semiconductor wafer chemical mechanical polishing (CMP) device, a polishing pad used in the device and a semiconductor wafer polishing method.

Background technique

In recent years, the miniaturization of semiconductor devices has been remarkable. In order to realize miniaturization of semiconductor devices, various new technologies have been developed in terms of manufacturing methods of semiconductor devices. Among these new technologies, the multilayer wiring technology in which wiring layers composed of metal wiring materials and insulating materials are laminated into several layers has greatly promoted the miniaturization and high performance of semiconductor devices, but there are also technical differences. kinds of subjects. One of the problems is securing flatness in each wiring layer. For example, if the flatness cannot be ensured, the unevenness remains on the upper surface of each wiring layer, and a focus shift occurs in a photolithography process which is critical for miniaturization, and wiring patterns cannot be formed. In order to solve this problem, in recent years, a chemical mechanical polishing (CMP) method in which the surface of a semiconductor wafer is chemically mechanically polished has been widely used.

Hereinafter, a CMP apparatus of the so-called tape polishing method other than the conventional rotary table method will be described with reference to the drawings.

FIG. 15 schematically shows the configuration of a polishing mechanism unit in a conventional CMP apparatus with a polishing method.

In the CMP apparatus shown in the figure, a plurality of sheet-shaped polishing pads 101 whose base material is made of foamed polyurethane are attached to a belt-shaped platen 102 at regular intervals. Then, by supplying abrasive agent, namely slurry, on the polishing pad 101, the fixed plate 102 is moved, and the holder 103 is rotated while pressing the surface of the semiconductor wafer 104 adsorbed on the holder 103 to polish the semiconductor wafer. 104. In addition, in order to activate (deburr) the upper surface of the polishing pad 101, the trimmer 106 mounted on the lower side of the cylinder 105 is pushed against the polishing pad 101, so that it moves vertically at any time relative to the running direction of the fixed disk 102. move. By activating the upper surface of the polishing pad 101, the polishing pad 101 can maintain the polishing force.

In addition, a conventional CMP apparatus includes, for example, an end point detection device (not shown) that surrounds a belt-shaped platen 102 . Through-holes 110 for endpoint detection are formed in each polishing pad 101 . The end point detection device detects the end point of polishing by irradiating laser light on, for example, the semiconductor wafer 104 through the through hole 110 and receiving reflected light from the semiconductor wafer 104 .

FIG. 16 is an enlarged view showing a portion D in the conventional CMP apparatus shown in FIG. 15 . This figure shows the part where the polishing pad 101 is pasted on the surface plate 102 at regular intervals. In addition, FIG. 17 is an enlarged view showing a portion E in the conventional CMP apparatus shown in FIG. 15 , and shows a through-hole 110 for polishing end point detection. Here, if the advance direction of the fixed disk 102 is called the longitudinal direction of the polishing pad 101, and the vertical direction of the fixed disk 102 in the surface of the polishing pad is called the width direction of the polishing pad, the through hole 110 is in the polishing pad 101. , when viewed in the width direction, opens near the center.

In addition, as shown in FIG. 15 and FIG. 16 , there is a constant interval between adjacent polishing pads 101 in the advancing direction, thereby enabling rapid discharge of grinding dust or slurry.

By employing the CMP apparatus described above, the upper surface of the semiconductor device can be flattened with high precision, and a fine wiring pattern can be formed.

Patent Document 1: JP-A-2001-176828

In the conventional CMP apparatus, during continuous use, as shown in FIG. 16 , damage 107 occurs at the portion facing the adjacent polishing pad 101 at the end of the polishing pad 101 . Similarly, in the peripheral portion of the through-hole 110 shown in FIG. 17 , scratches 107 are generated during polishing. The damage 107 is caused by the dresser 106 colliding with the polishing pad 101 when the surface plate 102 moves vertically at any time.

In addition, as shown in FIG. 16 , peeling is likely to occur no matter at the end portion, the middle, or the corner portion 108 of the polishing pad 101 . The reason for such peeling is as follows.

The polishing mechanism including the polishing pad 101, the fixed plate 102, the holder 103, and the like stands by in a wet protective atmosphere when the polishing apparatus is in an unloaded state. In addition, the fixed platen 102 to which the polishing pad 101 is attached continues to rotate in the shape of a conveyor belt in a state where a very strong tension is applied thereto. In addition, the polishing pad 101 during polishing receives a pressing force against the semiconductor wafer or a contact and pressing force from a dresser while being exposed to the slurry. If this state continues for a long time, the end of the polishing pad 101, which has a narrower bonding area with the surface plate, is immersed in water or slurry than other parts, and peeling occurs due to the interaction with the tensile stress.

If damage 107 or peeling occurs on the polishing pad 101, an abnormality will also occur in the semiconductor process.

First, when damage 107 occurs at the end of the polishing pad 101 and the peripheral edge of the through-hole for end point detection, the surface side (main surface side) of the semiconductor wafer 104 is pressed against the polishing pad 101 to perform polishing. Damage occurs on the main surface side of the wafer. Such damage to the main surface side of the wafer is a cause that significantly deteriorates the reliability of the semiconductor device and eventually induces defective products. Therefore, after CMP, it is necessary to inspect the semiconductor wafer for damage, and thus a lot of manpower is required.

Then, when the polishing pad 101 is peeled off, the semiconductor wafer 104 may be caught by the peeled portion of the polishing pad 101 during polishing, and the semiconductor wafer 104 may come off from the holder 103 and damage the semiconductor wafer 104 .

In addition, if a floating portion is generated at the end of the polishing pad 101 due to peeling, when the floating portion collides with the dresser 106, the dresser 106 and the cylinder on which it is mounted are damaged, and the equipment has to be stopped. Its repair requires a lot of time and expense.

In this way, with respect to the peeling of the corners of the polishing pad, the bonding strength of the adhesive bonding the platen 102 and the polishing pad 101 can be improved and the like assembled. However, in the case of improving the bonding strength between the fixed plate 102 and the polishing pad 101, although it can be bonded with sufficient strength after pasting, due to the application of tension while rotating, it is wet and under a chemical protective atmosphere. The mixture deteriorates rapidly. In addition, it is necessary to study the adhesive individually according to the slurry used, which is not suitable for small batch production.

Contents of the invention

An object of the present invention is to provide a polishing method, a polishing pad, and a polishing apparatus for polishing a semiconductor wafer without causing damage or breakage.

The first polishing pad of the present invention is a polishing pad used for chemical mechanical polishing, the upper surface of which is a polishing surface, and at least a part of the upper end is subjected to bevel processing or rounding processing.

Thus, when the polishing pad of the present invention is used in a polishing apparatus, since the dresser and the upper end of the polishing pad can be prevented from colliding, it is possible to prevent damage near the end. Therefore, the wafer can be polished without damage.

Viewed from above, it has a substantially quadrangular shape, and at least the upper end of a portion corresponding to one side of the substantially quadrangular shape is obliquely processed or rounded, so that when used in a grinding device with a grinding method, it is possible to prevent Damage occurs near the end. Therefore, the wafer can be polished without damage, and a highly reliable wafer can be manufactured.

Seen from above, it has a fan-shaped shape, and at least a part of the upper end is subjected to oblique processing or rounding processing, and when used in a turntable type polishing device that divides the polishing pad into multiple pieces, it can be used without damage to the wafer. Grind.

For example, if at least a part of the above-mentioned upper end is obliquely processed, and the angle of the above-mentioned upper end is an obtuse angle, since it can effectively prevent collision with the trimmer and reduce friction with the trimmer, it can prevent the Damage occurred nearby.

By setting the through-hole for oblique processing or rounding on the upper end of the peripheral edge, when used in a grinding device, damage caused by the dresser can be prevented from occurring near the through-hole, so the wafer can not be damaged. Grind. Therefore, wafers with higher reliability can be manufactured.

The 2nd polishing pad of the present invention is used for chemical mechanical polishing, and the upper surface is a polishing pad with a polishing surface, at least a part of the end is formed with a first concave-convex portion, and at least a part of the other end is formed to be compatible with the above-mentioned first. The second concave-convex part where the concave-convex part engages.

Thus, if the polishing pad is bonded with the first concave-convex portion and the second concave-convex portion and used in a polishing apparatus, since the stress on the platen or wafer can be effectively dispersed, peeling during polishing can be prevented. As a result, troubles such as sudden stop of the polishing device are less likely to occur, and the manufacturing cost of the semiconductor device can be reduced.

Seen from above, it has a substantially quadrilateral shape in which the first concave-convex portion is formed on the first side and the second concave-convex portion is formed on the opposite side of the first side, so it can be preferably used in a polishing device of a belt polishing method.

By further providing a through hole subjected to chamfering or rounding on the upper end of the peripheral edge portion, it is possible to suppress damage to the periphery of the through hole during grinding.

By performing oblique processing or rounding processing on the corner part when viewed from above, compared with the conventional polishing pad, since it is possible to prevent the polishing liquid or water from easily entering the corner part, the polishing pad of the present invention is used for When grinding the device, it is not easy to peel off during grinding.

It is particularly preferable to have a substantially quadrilateral shape in which four corners are cut or rounded to form a curve when viewed from above.

The 3rd polishing pad of the present invention is used for chemical mechanical polishing, and the upper surface is a polishing pad, wherein the first protruding portion formed by protruding the upper part of the above-mentioned end portion is formed on at least a part of the end portion; A second protruding portion formed by protruding the lower portion of the end portion so as to overlap with the first protruding portion is formed on at least a part of the other end portion.

Thus, when a plurality of polishing pads of the present invention are used in a polishing device, the first protruding portion is arranged on the upstream side with respect to the running direction of the fixed plate, and by overlapping the first protruding portion and the second protruding portion, It is possible to suppress the occurrence of damage caused by the dresser. In addition, since it is possible to prevent the polishing liquid or water from penetrating into the lower surface of the polishing pad, it is possible to prevent peeling during polishing.

Since it has a substantially quadrilateral shape when viewed from above, the first protrusion is formed on the first side, and the second protrusion is formed on the opposite side of the first side, it can be preferably used in a grinding device of a belt grinding method.

A fourth polishing pad of the present invention is a polishing pad having a polishing surface for chemical mechanical polishing, wherein through-holes are provided with beveled or rounded upper ends of the peripheral edges.

Thus, when the polishing pad of the present invention is used in a polishing apparatus, the end point of polishing can be monitored from the through hole during polishing, and at the same time, damage can be prevented near the through hole.

The 1st lapping device of the present invention has: fixed disk, a plurality of polishing pads that are pasted on the above-mentioned fixed disk at intervals with each other and use the upper surface as a polishing surface, a holder for holding a wafer during polishing, and a mechanism for activating the above-mentioned plurality of polishing pads. The above dresser is a polishing device for chemical mechanical polishing; among the respective upper ends of the plurality of polishing pads, oblique processing or rounding processing is performed on portions facing adjacent polishing pads.

This prevents the dresser from colliding with the upper end of the polishing pad during polishing, thereby preventing damage to the vicinity of the end. Therefore, polishing can be performed without damaging the wafer.

In addition, it also includes at least 2 rollers with rotating shafts parallel to each other, and the above-mentioned fixed disk is a belt-shaped fixed disk suspended on the above-mentioned rollers; the above-mentioned polishing pad can also have an upper end portion with at least one side that is obliquely processed Or rounded roughly quadrilateral shape.

The 2nd lapping apparatus of the present invention has: fixed disk, a plurality of polishing pads that are pasted on the above-mentioned fixed disk and use the upper surface as a polishing surface, a holder for holding a wafer during polishing, and a dressing for activating the upper surface of the above-mentioned plurality of polishing pads. The device is a polishing device for chemical mechanical polishing; at least part of the ends of each of the above-mentioned polishing pads is formed with a first concave-convex portion; The second concave-convex portion engaged with the above-mentioned first concave-convex portion.

Thus, if the polishing pad is bonded with the first concave-convex portion and the second concave-convex portion, it is used in a polishing device, since the stress applied to the end of the polishing pad from the fixed disk or the wafer can be effectively dispersed, so it can be prevented from peeling off during polishing. abrasive pad. As a result, troubles such as sudden stop of the polishing device are less likely to occur, and it is also possible to suppress an increase in manufacturing cost due to failure.

Each of the plurality of polishing pads may have a substantially quadrilateral shape in which the first concave-convex portion is formed on a first side and the second concave-convex portion is formed on an opposite side of the first side when viewed from above.

The 3rd lapping device of the present invention has: fixed plate, mutually spaced on above-mentioned fixed plate affixed on the above-mentioned fixed plate and use the polishing pad of upper surface as grinding surface, the holder that holds wafer when polishing, the upper surface of activation above-mentioned plurality of polishing pads The dresser is a polishing device used for chemical mechanical polishing; each of the plurality of polishing pads performs oblique processing or rounding processing on the corner parts viewed from above.

Thereby, since the stress applied to the end portion of the polishing pad from the platen or the wafer can be effectively dispersed, it is possible to prevent the polishing pad from peeling off during polishing. As a result, troubles such as sudden stop of the polishing device are less likely to occur, and the manufacturing cost of the semiconductor device can be reduced.

The 4th lapping apparatus of the present invention has: fixed disk, a plurality of polishing pads that are pasted on the above-mentioned fixed disk and use the upper surface as a polishing surface, a holder for holding a wafer during polishing, and a dressing for activating the upper surface of the plurality of polishing pads. The device is a polishing device for chemical mechanical polishing; in each of the above-mentioned polishing pads, when viewed from the direction of movement during polishing, a first protruding portion that protrudes from the upper portion is formed at the end portion on the upstream side, and each of the above-mentioned polishing pads In the pad, when viewed in the operating direction during polishing, the downstream end protrudes from the bottom to form a second protruding portion overlapping the first protruding portion of the adjacent polishing pad.

Thereby, damage to the end portion of the polishing pad by the dresser can be suppressed. In addition, since it is possible to prevent the polishing liquid or water from penetrating into the lower surface of the polishing pad, it is possible to prevent the polishing pad from being peeled off during polishing.

Each of the above-mentioned plurality of polishing pads has a substantially quadrilateral shape when viewed from above, the first protrusion is formed on a first side, and the second protrusion is formed on an opposite side of the first side.

The 5th lapping device of the present invention has fixed disk, a plurality of polishing pads that are pasted on the above-mentioned fixed disk at intervals and use the upper surface as a grinding surface, a holder for holding a wafer during polishing, and activating the upper surface of the above-mentioned plurality of polishing pads. The dresser is a polishing device for chemical mechanical polishing; an adhesive is embedded between the plurality of polishing pads.

This prevents the polishing liquid or water from intruding from the end of the polishing pad, so that the polishing pad is less likely to be peeled off during polishing. Therefore, the wafer can be polished smoothly without causing a problem.

The 6th lapping apparatus of the present invention has fixed disk, a plurality of polishing pads that are pasted on the above-mentioned fixed disk at intervals and use the upper surface as a polishing surface, a holder for holding a wafer during polishing, and activating the upper surface of the above-mentioned plurality of polishing pads. The dresser of the present invention is a polishing device for chemical mechanical polishing; each of the plurality of polishing pads is provided with a through hole in which the upper end of the peripheral edge portion is beveled or rounded.

Thus, during polishing, since the peripheral edge portion of the through hole is less likely to be damaged, the wafer can be polished without causing damage.

The 1st wafer lapping method of the present invention is the lapping method that adopts the lapping device that has fixed disc and the multiple lapping pads that are pasted on the above-mentioned fixed disc at intervals and with the upper surface as the grinding surface, including using a dresser to make the above-mentioned plurality of pads The step (a) of activating the upper surface of the polishing pad and the step (b) of pushing the above-mentioned wafer to the upper surface of the above-mentioned polishing pad while running the above-mentioned fixed disk; the above-mentioned step (a) and step (b) In the above-mentioned polishing pad to be used, in the upper end portion, the part facing the adjacent above-mentioned polishing pad is subjected to bevel processing or rounding processing.

According to this method, since the polishing pad is less likely to be damaged in the step (a), it is possible to perform polishing without damaging the wafer in the step (b).

The 2nd wafer lapping method of the present invention is to adopt the lapping method of the lapping device that adopts fixed plate and sticking on above-mentioned fixed plate and a plurality of lapping pads with the upper surface as grinding surface, comprises utilizing dresser to make above-mentioned a plurality of lapping pads The step (a) of activating the upper surface and the step (b) of pushing the above-mentioned wafer to the upper surface of the above-mentioned polishing pad while moving the above-mentioned fixed plate; In the end portion of the polishing pad, a first concave-convex portion and a second concave-convex portion engaged with the first concave-convex portion of the adjacent polishing pad are formed.

If this method is adopted, since the polishing pad can be prevented from being peeled off during polishing, it is possible to suppress the emergency stop of the polishing apparatus or the collision of the dresser and the peeling part of the polishing pad in the step (a).

The 3rd wafer lapping method of the present invention is the lapping method that adopts the lapping apparatus that has fixed disk and a plurality of polishing pads that are pasted on the above-mentioned fixed disk and uses the upper surface as a grinding surface, including utilizing a dresser to make the above-mentioned plurality of polishing pads The step (a) of activating the upper surface and the step (b) of pushing the above-mentioned wafer to the upper surface of the above-mentioned polishing pad while moving the above-mentioned fixed plate; The end portion of the above-mentioned polishing pad is subjected to bevel processing or rounding processing on the corner portion viewed from above.

Thereby, since the stress applied to the end portion of the polishing pad from the platen or the wafer can be effectively dispersed, the polishing pad is less likely to be peeled off during polishing.

The 4th wafer lapping method of the present invention is the lapping method that adopts the lapping apparatus that has fixed disk and a plurality of polishing pads that are pasted on the above-mentioned fixed disk and uses the upper surface as a grinding surface, including utilizing a dresser to make the above-mentioned plurality of polishing pads The step (a) of activating the upper surface and the step (b) of pushing the above-mentioned wafer to the upper surface of the above-mentioned polishing pad while moving the above-mentioned fixed plate; In the above-mentioned polishing pad, viewed from the running direction of the above-mentioned fixed disk, at the end part on the upstream side, a first protruding part that makes the upper part protrude is formed, and at the end part on the downstream side, the above-mentioned grinding pad adjacent to the above-mentioned grinding pad is formed that makes the lower part protrude. A second protruding portion where the above-mentioned first concavo-convex portion of the pad overlaps.

According to this method, it is possible to suppress damage to the end portion of the polishing pad by the dresser in the step (a). In addition, since it is possible to prevent the polishing liquid or water from penetrating into the lower surface of the polishing pad, it is also possible to prevent the polishing pad from being peeled off during polishing.

The 5th wafer lapping method of the present invention is the lapping method that adopts the lapping device that has fixed plate and the multiple grinding pads that are pasted on the above-mentioned fixed plate at intervals with each other and use the upper surface as the grinding surface, including using a dresser to make the above-mentioned multiple The step (a) of activating the upper surface of the polishing pad and the step (b) of pressing the above-mentioned wafer on the upper surface of the polishing pad to perform polishing while the above-mentioned fixed plate is running; in the above-mentioned step (a) and step (b ) between the above-mentioned plurality of polishing pads used, the adhesive is embedded.

According to this method, since the intrusion of the polishing liquid or water from the end of the polishing pad can be prevented, peeling of the polishing pad can be suppressed during polishing. Therefore, the wafer can be polished smoothly without causing a malfunction.

The grinding method of the 6th wafer of the present invention is the grinding method that adopts the polishing device that has fixed plate and the multiple grinding pads that are pasted on the above-mentioned fixed plate at intervals with each other and use the upper surface as the grinding surface, including using a dresser to make the above-mentioned multiple The step (a) of activating the upper surface of each polishing pad and the step (b) of pushing the above-mentioned wafer to the upper surface of the polishing pad while moving the above-mentioned fixed plate; b) Each of the above-mentioned polishing pads to be used is provided with a through hole in which the upper end of the peripheral edge portion is beveled or rounded.

According to this method, during polishing, since the peripheral edge portion of the through hole is less likely to be damaged, polishing can be performed without damaging the wafer.

Description of drawings

FIG. 1 is a diagram schematically showing the configuration of a polishing mechanism unit in a CMP apparatus with a polishing method according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged perspective view showing a part A of the CMP apparatus according to Embodiment 1 shown in FIG. 1 .

3 is an enlarged cross-sectional view in the longitudinal direction of part A in the CMP apparatus according to Embodiment 1. FIG.

FIG. 4 is an enlarged cross-sectional view showing a modified example of a portion A shown in FIG. 1 in the CMP apparatus of Embodiment 1. FIG.

FIG. 5 is an enlarged cross-sectional view showing a modified example of part A shown in FIG. 1 in the CMP apparatus of Embodiment 1. FIG.

6 is an enlarged perspective view showing a portion B of the polishing pad in the CMP apparatus according to Embodiment 1. FIG.

FIG. 7 is an enlarged cross-sectional view showing a portion B of the polishing pad of the CMP apparatus shown in FIG. 1 .

8 is a perspective view showing a polishing pad used in a CMP apparatus according to Embodiment 2 of the present invention.

9 is a perspective view showing a polishing pad used in a CMP apparatus according to Embodiment 3 of the present invention.

10 is a perspective view showing a polishing pad used in a CMP apparatus according to Embodiment 4 of the present invention.

11 is an enlarged cross-sectional view of a portion C shown in FIG. 10 of the polishing pad according to Embodiment 4. FIG.

12 is a perspective view showing the structure between polishing pads in the CMP apparatus according to Embodiment 5 of the present invention.

13 is a cross-sectional view of the end portion of the polishing pad and the platen when cut in the longitudinal direction in the CMP apparatus according to Embodiment 5. FIG.

14( a ) is a side view of a CMP apparatus according to Embodiment 6 of the present invention, and ( b ) is a plan view of a polishing pad of the CMP apparatus seen from above.

FIG. 15 is a diagram schematically showing the configuration of a polishing mechanism unit in a conventional tape polishing CMP apparatus.

FIG. 16 is an enlarged view showing a portion D in the conventional CMP apparatus shown in FIG. 15 .

FIG. 17 is an enlarged view showing a portion E of the conventional CMP apparatus shown in FIG. 15 .

In the picture:

1 roll

2. 21 Fixed order

3, 22 grinding pad

4 end

5, 23 Semiconductor chips

6 cylinder

7. 26 Trimmer

8 through holes

9 Circumferential edge

10 bump

11 Corner

12 incision part

13 Adhesive

16, 24 retainer

25 powder slurry

Detailed ways

The inventors of the present application first tried to optimize the arrangement interval of a plurality of sheet-shaped polishing pads and improve the dresser in order to prevent damage to the polishing pad in a belt polishing type polishing apparatus. However, in the conventional polishing mechanism, damage to the polishing pad cannot be significantly reduced. In addition, changing the material of the polishing pad has also been studied, but it is difficult to select a material that does not cause damage while properly polishing the wafer. Therefore, the inventors of the present application pay attention to the end portion with the corner of the polishing pad, and when changing the shape of the end portion of the sheet-like polishing pad, it is found that the collision between the dresser and the polishing pad can be prevented, and the grinding effect can be suppressed. Damage occurs on the pad.

That is, in the polishing device, by performing oblique processing (chamfering processing) or rounding processing on the upper end portion of the polishing pad facing the adjacent polishing pad, the upper end portion of the dresser and the polishing pad Do not collide and can suppress the occurrence of damage. In addition, when the same processing is performed on the through-hole of the polishing pad, the occurrence rate of damage to the peripheral edge of the through-hole is significantly reduced compared with conventional ones. In addition, in this specification, "rounding processing" refers to the processing method of rounding corners, such as a corner part and an upper end part.

In addition, by processing the shape of the corner or end of the polishing pad into a shape that is less likely to concentrate the tension from the platen or the stress of the dresser and the wafer, it was found that peeling from the platen of the polishing pad can also be suppressed. In addition, the peeling of the polishing pad can also be suppressed by forming a shape in which liquid such as slurry or water hardly enters between the polishing pad and the fixed plate.

Embodiments of the present invention will be described below using the drawings.

Embodiment 1

FIG. 1 is a diagram schematically showing the configuration of a polishing mechanism unit in a CMP apparatus with a polishing method according to Embodiment 1 of the present invention.

As shown in this figure, the polishing mechanism part in the CMP apparatus of the present embodiment has: two rollers (pulleys) 1 arranged in parallel with each other with rotation axes, a belt-shaped fixed disk 2 suspended on the rollers 1, and a Sheets and the like are pasted on the outer surface of the fixed disk 2, such as four sheet-shaped polishing pads 3, a holder 16 for holding the semiconductor wafer 5, a cylinder 6, and a polishing pad 3 mounted on the cylinder 6 when grinding. The dresser 7 activated (burr-removed) on the upper surface, and the detection device (not shown) for detecting the grinding end point. The polishing pad 3 is made of, for example, polyurethane, especially independently foamed polyurethane, and has a rectangular shape.

In addition, through-holes 8 for detecting the end point of polishing are formed in the fixed platen 2 and the polishing pad 3 . The through hole 8 is provided for transmitting light such as laser light irradiated from a detection device provided below the fixed plate 2 . The detection device detects the end point of polishing by detecting the laser light reflected by the semiconductor wafer.

The polishing method of the semiconductor wafer using the CMP apparatus (polishing apparatus) of this embodiment is the same as conventionally.

That is, the semiconductor wafer 5 is held by the holder 16 so that the main surface thereof overlaps the polishing pad during polishing. The holder 16 during grinding rotates about a line passing through the center of the semiconductor wafer 5 in a vertical line facing the grinding surface as an axis.

The band-shaped fixed disk 2 rotates in the manner of a conveyor belt.

The dresser 7 that is arranged on the cylinder 6 below, when grinding, with the state of being in contact with the top of the grinding pad 3, moves to the vertical direction relative to the advancing direction of the grinding pad 3, so that the finishing of the grinding pad 3 is carried out. The upper surface of the polishing pad 3 is burred. In addition, on the polishing surface of the polishing pad 3, the direction perpendicular to the advancing direction is called "width direction", and the direction parallel to the advancing direction is called "longitudinal direction".

In this manner, the semiconductor wafer 5 is rotated while the polishing pad 3 is moved in the advancing direction, thereby performing polishing. At this time, the slurry containing abrasive particles is supplied to the polishing pad 3

Next, the characteristics of the polishing pad 3 of this embodiment, that is, the shape of the end portion of the polishing pad and the peripheral edge portion of the through hole 8 will be described.

2 is an enlarged perspective view showing part A of the CMP apparatus of this embodiment shown in FIG. 1 , and FIG. 3 is an enlarged cross-sectional view of part A in the longitudinal direction of the CMP apparatus of this embodiment. In addition, part A in FIG. 1 is a bonding part of the plurality of polishing pads 3 to the fixed plate 2 .

As shown in FIGS. 2 and 3 , in the CMP apparatus of the present embodiment, the upper end portion of the polishing pad 3 that faces the adjacent polishing pad 3 (end portion 4 ) is obliquely cut. Therefore, as shown in FIG. 3 , the fixed plate 2 on the portion A forms an acute angle with the side end surface of the polishing pad 3 , and the upper end of the polishing pad 3 forms an obtuse angle.

Accordingly, during polishing, the upper end portion of the polishing pad 3 does not catch the dresser 7, the polishing pad 3 can be activated, and the damage that conventionally occurred at the end portion of the polishing pad 3 can be prevented. Therefore, according to the CMP apparatus of this embodiment, CMP can be performed without damaging the main surface of a semiconductor wafer.

In particular, in the CMP apparatus of this embodiment, since the lower end surface of the polishing pad 3 forms an acute angle, the dresser 7 and the polishing pad 3 are less likely to be caught. In addition, such a shape can be easily formed by general oblique processing.

In addition, in FIGS. 1 to 3 , examples are shown in which the polishing pads 3 are attached to the surface plate 2 with predetermined intervals therebetween, but the polishing pads may be arranged without intervals. The polishing pad 3 of this embodiment, even in the state of being arranged on the fixed plate 2 without gaps, can ensure a space for discharging the slurry or grinding debris, so while preventing the slurry or water from entering the inside of the polishing pad 3, , can also continue to grind well.

In addition, FIGS. 4 and 5 are both enlarged cross-sectional views showing a modified example of the portion A shown in FIG. 1 in the CMP apparatus of the present embodiment.

Even if the end portion 4 of the polishing pad 3 has a chamfered (oblique) shape as shown in FIG. 4 , the above-mentioned effects can be obtained. That is, the angle of the portion of the upper end portion of the polishing pad 3 that faces the adjacent polishing pad may form an obtuse angle exceeding 90 degrees by oblique processing. At this time, since the upper end portion 4 of the polishing pad 3 is less likely to collide with the dresser 7, damage to the end portion 4 of the polishing pad 3 is also less likely to occur.

In addition, the end portion 4 of the polishing pad 3 may be rounded as shown in FIG. 5 . In this way, by rounding the upper end of the polishing pad 3 with a blade or a file, the upper end of the polishing pad 3 is less likely to catch the dresser 7 .

In addition, as described above, it is also effective to perform the same processing as that of the end portion of the polishing pad 3 on the peripheral edge portion of the through hole 8 .

6 is an enlarged perspective view showing part B of the CMP apparatus shown in FIG. 1 , and FIG. 7 is an enlarged cross-sectional view showing part B of the polishing pad of the CMP apparatus shown in FIG. 1 . In addition, in FIG. 1 , part B represents the through-hole 8 . In addition, FIG. 7 shows cross sections in the longitudinal direction of the platen 2 and the polishing pad 3 .

As shown in FIG. 6 and FIG. 7, in the polishing pad 3 used in the CMP apparatus of this embodiment, the angle of the upper end of the peripheral edge portion 9 of the through hole 8 is an obtuse angle in the cross section in the longitudinal direction.

Therefore, even at the peripheral edge portion 9 of the through hole 8 , the upper end portion of the polishing pad 3 is less likely to collide with the dresser 7 , and it is possible to suppress the occurrence of damage on the upper surface of the conventional semiconductor wafer. In addition, the activation of the polishing pad 3 can be stably and smoothly performed by the dresser 7 .

In addition, like the end portion 4 shown in FIG. 3 , the shape of the peripheral edge portion 9 of the through hole 8 may be cut obliquely, and the through hole 8 may be rounded like the end portion 4 shown in FIG. 5 . The peripheral edge portion 9. Also in the above case, since the collision between the trimmer 7 and the peripheral edge portion 9 can be suppressed, damage to the peripheral edge portion 9 is less likely to occur.

As described above, in the CMP apparatus of this embodiment, by forming the shape of the end portion 4 of the polishing pad 3 and the peripheral edge portion 9 of the through hole 8 so that the dresser 7 is less likely to be caught or the friction is reduced, the Damage occurs on the polishing pad 3 .

In addition, on the polishing pad 3 used in the CMP apparatus of this embodiment, in FIGS. The above-mentioned processing can also obtain the same effect as the above-mentioned examples if the above-mentioned processing is performed only on the end portion on the downstream side. However, when processing both ends of the upstream side and the downstream side of the polishing pad 3, since it is easy to align the position when sticking on the fixed plate 2, it can also be installed on the device without paying attention to the directionality, so it is preferable.

In addition, in this embodiment, four polishing pads 3 are attached to the belt-shaped platen 2 as an example in the CMP apparatus, but the number of polishing pads 3 is not particularly limited. The width of the polishing pad 3 is preferably at least larger than the diameter of the semiconductor wafer 5 with an appropriate margin.

Embodiment 2

8 is a perspective view showing a polishing pad used in a CMP apparatus according to Embodiment 2 of the present invention. In addition, in this figure, the same components as those in Embodiment 1 are assigned the same symbols. In addition, since the CMP apparatus of this embodiment is the same as Embodiment 1 except for the shape of the polishing pad and the method of sticking it, only the shape of the polishing pad and the method of sticking it will be described below.

As shown in FIG. 8 , on the polishing pad 3 according to the present embodiment, asperities 10 are formed on the upstream and downstream ends as viewed in the advancing direction. The unevenness 10 has a shape capable of engaging with the unevenness 10 of the adjacent polishing pad.

In addition, in the CMP apparatus of this embodiment, the plurality of polishing pads 3 can be attached to the platen 2 without gaps by engaging the respective adjacent polishing pads 3 and unevenness.

The shape of the unevenness 10 is not particularly limited as long as it is a shape capable of engaging with an adjacent polishing pad. In addition, there is no limitation on the number of recesses or protrusions to be formed.

By setting such unevenness 10 on the polishing pad 3, since the contact area with the adjacent polishing pad 3 can be increased, the tension applied to the polishing pad 3 can be dispersed according to the tension (tensile stress) applied to the given disk 2. stress. In addition, since the bonded surface of the platen 2 and the polishing pad 3 can be avoided from being in direct contact with the moist and chemically protective atmosphere, peeling from the ends of the polishing pad 3, especially from the corners, can be suppressed. Therefore, in the CMP apparatus using the polishing pad of the present embodiment, inconveniences such as sudden stop due to peeling of the polishing pad are less likely to occur. In addition, since the life of the polishing pad 3 can be extended, the manufacturing cost of the semiconductor device can also be reduced.

Embodiment 3

9 is a perspective view showing a polishing pad used in a CMP apparatus according to Embodiment 3 of the present invention.

As shown in the figure, the polishing pad 3 for use in a CMP apparatus according to this embodiment is viewed from above, and the corners of the corners 11 are cut by chamfering or the like. Through such processing, it is possible to cut all the corners to 90 degrees or less when viewed from above. In addition to chamfering, rounding or the like may be used to process the side end surfaces of the corners into a curved surface such as a circle.

Since the conventional polishing pad has a rectangular shape, the stress applied to the corners from the surface plate 22 is concentrated, and slurry, water, and the like are likely to enter. In contrast, in the CMP apparatus of the present embodiment, since the corners of the corners 11 of the polishing pad 3 are cut off, the polishing pad 3 can be dispersed according to the tension (tensile stress) applied to the given disk 2. The stress, can not easily peel off the polishing pad 3. In addition, since liquid such as slurry or water is also difficult to enter into the joint portion between the fixed plate 2 and the polishing pad 3, it does not peel off from the polishing pad 3. Therefore, according to the CMP apparatus of this embodiment, during polishing, it is possible to suppress sudden stop, etc., and to suppress failures.

In addition, in order to secure the area for polishing the semiconductor wafer, the range where the above-mentioned chamfering or rounding is performed on the polishing pad 3 of the present embodiment is preferably within about 40 mm from the width direction.

Embodiment 4

10 is a perspective view showing a polishing pad used in a CMP apparatus according to Embodiment 4 of the present invention. In addition, FIG. 11 is an enlarged cross-sectional view of a portion C shown in FIG. 10 of the polishing pad according to this embodiment. In addition, in this figure, the cross section of the platen 2 and the polishing pad 3 in the advance direction (longitudinal direction) of the platen is shown.

As shown in FIG. 11 , in the polishing pad 3 of the present embodiment, cutouts 12 are formed at the ends on the upstream side and downstream side when viewed in the advancing direction. The notch 12 is formed such that the upper part protrudes from the lower part at the upstream end as viewed in the advancing direction, and the lower part protrudes from the downstream end so that it can engage with the upstream end. The shapes of the protruding portion at the upstream end and the protruding portion at the downstream end are not particularly limited as long as they can be engaged. However, as shown in FIG. The selection of the end, such as studying whether it is suitable for the material of the polishing pad, is determined during production.

In the CMP apparatus of the present embodiment, the above-mentioned polishing pad 3 is attached to the platen 2 in a state where a plurality of polishing pads 3 are overlapped (engaged) with the notch 12 at the end. At this time, as shown in FIG. 11 , the downstream notch 12 of the polishing pad 3 arranged on the upstream side overlaps with the upstream notch 12 of the polishing pad 3 arranged on the downstream side. Therefore, since the dresser 7 is less likely to be caught by the end portion of the polishing pad 3 during polishing of the semiconductor wafer 5 (see FIG. 1 ), activation of the pad can be smoothly performed. Therefore, polishing can be performed without damaging the main surface of the semiconductor wafer 5 . In addition, by forming the notch 12 at the end of the polishing pad 3, the bonded surface of the platen 2 and the polishing pad 3 can be prevented from directly contacting the wet and chemical protective atmosphere, and peeling of the polishing pad 3 can be suppressed. Therefore, the processing steps of the semiconductor wafer can be smoothly performed.

Embodiment 5

12 is a perspective view showing the structure between polishing pads in the CMP apparatus according to Embodiment 5 of the present invention. 13 is a cross-sectional view of the end portion of the polishing pad and the platen when cut in the longitudinal direction in the CMP apparatus of the present embodiment.

As shown in FIG. 12 , in the CMP apparatus of this embodiment, a plurality of polishing pads 3 are attached to the platen 2 , and an adhesive 13 is applied between the adjacent polishing pads 3 . The adhesive 13 is applied and cured when, for example, the polishing pad 3 is attached to the platen 2 .

In addition, the adhesive 13 is applied so as not to exceed the height of the polishing pads 3 after curing and not to protrude from the gap between the polishing pads.

Thereby, since can carry out the polishing of semiconductor wafer, so can prevent the end portion of polishing pad 3 from being peeled off during polishing because can not directly contact with the mode of moisture and chemical protective atmosphere with the bonding surface of platen 2 and polishing pad 3. In addition, since the ends of the polishing pad 3 are physically bonded by the adhesive 13, it is more difficult to peel off the polishing pad 3.

As the adhesive used here, it is preferable to use one that has excellent chemical resistance and is easy to cure, for example, an epoxy-based curable adhesive. In particular, when an epoxy-based resin is used, stress applied to the polishing pad 3 can be relieved due to its stretchability. When such an adhesive is used, after bonding the polishing pad 3, the adhesive is applied to the gap between the polishing pads and cured by a heat source such as a drier. Then, polishing of the semiconductor wafer is performed.

In addition, in FIG. 13 , the upper end of the polishing pad 3 is rounded as an example, but the polishing pad 3 may have the same shape as conventional ones, or may have the shapes described in Embodiment 1 and Embodiment 3. However, in the case of using the polishing pad of Embodiment 1, since scratches are less likely to occur during polishing and the polishing pad is less likely to be peeled off, a synergistic effect can be expected. When the polishing pad according to Embodiment 3 is used, it is preferable that the detachment suppression effect of the polishing pad can be enhanced.

Embodiment 6

In the above embodiments, the example in which the end portion of the polishing pad is processed in the CMP apparatus of the tape polishing method has been described. In contrast, even in a rotary disk type CMP apparatus, it may be necessary to process the end of the polishing pad.

In a conventional turntable-type CMP apparatus, a circular polishing pad is attached to a disk-shaped table top, and polishing is performed by pressing a semiconductor chip or a dresser to be polished from above on the polishing pad. In such a conventional CMP apparatus, as the polishing pad, only one circular pad is used, so the problem of damage to the end of the polishing pad and the stoppage of the device due to peeling will not occur as the subject of the present invention. unpleasant sight. However, compared with the belt polishing method, since the polishing pad is large, it is difficult to paste the polishing pad without air bubbles entering between the polishing pad and the fixed plate, and sometimes defects occur during polishing due to the presence of air bubbles. In addition, even if air bubbles or cracks occur in one part of the polishing pad, the entire polishing pad must be replaced, resulting in an increase in production cost.

In order to solve the above disadvantages, a turntable type CMP apparatus in which a polishing pad is divided into a plurality of sheets has been proposed. As a result, air bubbles are less likely to enter when the polishing pad is attached to the polishing table, so the polishing pad can be attached to the polishing table without bending. In addition, since the polishing pad of the damaged portion can be partially replaced, the cost of the polishing pad can be reduced. In addition, since the polishing pad is divided, it is easy to attach and peel off the polishing pad.

However, by dividing the circular polishing pad into multiple pieces, it is unfavorable that the polishing pad is peeled off or the end of the polishing pad is damaged, as in the CMP apparatus of the belt polishing method.

Therefore, the present inventors considered that the method of processing the end portion of the polishing pad, which is effective in the CMO of the belt polishing method, can also be applied to the rotary disk type CMP.

14( a ) is a side view of a CMP apparatus according to Embodiment 6 of the present invention, and ( b ) is a plan view of the polishing pad of the CMP apparatus according to this embodiment seen from above.

As shown in Figure 14 (a), the CMP apparatus of the present embodiment has: a fixed plate 21, a polishing pad 22 pasted on the fixed plate 21, a holder 24 having a rotating mechanism and a pressurizing mechanism and holding a semiconductor wafer 23 . A dresser 26 which has a rotating mechanism and a pressurizing mechanism and burrs the upper surface of the polishing pad 22 .

As shown in FIG. 14( b ), the polishing pad 22 of this embodiment is formed in a shape obtained by dividing a conventional polishing pad into a plurality of sheets. For example, in the CMP apparatus of the present embodiment, four fan-shaped polishing pads 22 are attached to the platen 21 with no gap between them. In addition, among the polishing pads 22 , the portions connecting adjacent polishing pads, that is, the end portions of the respective polishing pads 22 are processed into oblique shapes.

In this way, by adhering a processed shape or a beveled spacer in which the corners of the bonded portions between the spacers are cut off, it is possible to prevent the sticking portion of the polishing pad 22 from being caught by the dresser. Thereby, it is possible to prevent damage caused by the sticking portion being caught on the dresser, and it is possible to efficiently discharge the polished slurry or grinding dust toward the outer peripheral direction of the polishing pad 22 .

In addition, irregularities may be formed on the side of the polishing pad 22, and the polishing pad 22 may be bonded to the fixed plate 21 by combining the irregularities. In addition, an adhesive can also be used to fill the gap between adjacent polishing pads to prevent water or slurry 25 from entering the joint between the polishing pad 22 and the fixed plate 21 .

In addition, in FIG. 14( b ), four polishing pads 22 are pasted on the fixed plate 21 , but the number of polishing pads 22 is not particularly limited.

According to the CMP apparatus of the present invention, by applying beveling or rounding to the end of the polishing pad, the polishing pad is less likely to catch the dresser and damage can be prevented. In addition, since the stress received from the platen can be dispersed by forming the unevenness at the end portion of the polishing pad, peeling of the polishing pad can be suppressed.

In addition, by performing polishing using these CMP apparatuses, it is possible to perform polishing without damaging the main surface of the semiconductor chip.

Claims (30)

1. A polishing pad for chemical mechanical polishing, the upper surface of which is a polishing surface,

wherein,

at least a part of the upper end is subjected to a beveling or rounding process.

2. The polishing pad of claim 1, wherein,

the upper end of a portion having a substantially quadrangular shape when viewed from above and corresponding to at least 1 side of the substantially quadrangular shape is subjected to chamfering or rounding.

3. The polishing pad of claim 1, wherein,

the upper end portion of the cylindrical body has a fan-like shape when viewed from above, and is at least partially beveled or rounded.

4. The polishing pad of claim 1, wherein,

at least a part of the upper end is processed into an oblique shape, and the angle of the upper end is an obtuse angle.

5. The polishing pad according to any one of claims 1 to 4,

and a through hole formed in the upper end of the peripheral edge portion and subjected to a beveling process or a rounding process.

6. A polishing pad for chemical mechanical polishing, the upper surface of which is a polishing surface,

wherein,

forming a 1 st concavo-convex part at least in a part of an end portion;

at least a part of the other end is formed with a 2 nd concave-convex part which can be engaged with the 1 st concave-convex part.

7. The polishing pad of claim 6, wherein,

the first concave-convex part is formed on the 1 st side, and the second concave-convex part is formed on the opposite side of the 1 st side.

8. The polishing pad of claim 6 or 7,

and a through hole formed in the upper end of the peripheral edge portion and subjected to a beveling process or a rounding process.

9. A polishing pad for chemical mechanical polishing, the upper surface of which is a polishing surface,

wherein,

the corner portion when viewed from above is subjected to chamfering or rounding.

10. The polishing pad of claim 9, wherein,

the shape of the substantially rectangular shape is a shape in which four corners are cut off or rounded and a curve is formed when viewed from above.

11. The polishing pad of claim 9 or 10,

and a through hole formed in the upper end of the peripheral edge portion and subjected to a beveling process or a rounding process.

12. A polishing pad for chemical mechanical polishing, the upper surface of which is a polishing surface,

wherein,

forming a 1 st protruding part formed by protruding an upper part of the end part at least on a part of the end part;

at least a part of the other end is formed with a 2 nd protrusion which can overlap with the 1 st protrusion and is formed by protruding the lower part of the end.

13. The polishing pad of claim 12, wherein,

the projection has a substantially quadrangular shape when viewed from above, and the 1 st projection is formed on the 1 st side, and the 2 nd projection is formed on the opposite side of the 1 st side.

14. The polishing pad of claim 12 or 13,

and a through hole formed in the upper end of the peripheral edge portion and subjected to a beveling process or a rounding process.

15. A polishing pad for chemical mechanical polishing, the upper surface of which is a polishing surface,

wherein,

a through hole is formed in the upper end of the peripheral edge portion, and the upper end of the peripheral edge portion is subjected to oblique machining or rounding machining.

16. A polishing apparatus for chemical mechanical polishing of a wafer, comprising:

a fixed disc,

A plurality of polishing pads attached to the surface plate at intervals and having an upper surface as a polishing surface,

A holder for holding the wafer during polishing,

Activating the dresser on the plurality of polishing pads,

in the upper end portion of each of the plurality of polishing pads, a portion facing the adjacent polishing pad is subjected to chamfering or rounding.

17. The polishing apparatus as set forth in claim 16,

further comprising at least 2 rollers having axes of rotation parallel to each other;

the fixed plate is a belt-shaped fixed plate hung on the roller;

the polishing pad has a substantially quadrangular shape in which the upper end of at least 1 side is processed in an oblique or rounded shape.

18. A polishing apparatus for chemical mechanical polishing of a wafer, comprising:

a fixed disc,

A plurality of polishing pads adhered to the fixed plate and having an upper surface as a polishing surface,

A holder for holding the wafer during polishing,

Activating the dresser on the plurality of polishing pads,

forming a 1 st uneven portion at least in a part of an end portion of each of the polishing pads;

a 2 nd uneven portion that engages with the 1 st uneven portion of the adjacent polishing pad is formed in a part of the other end portion of each of the polishing pads.

19. The polishing apparatus as set forth in claim 18,

each of the polishing pads has a substantially rectangular shape in which the 1 st uneven portion is formed on the 1 st side and the 2 nd uneven portion is formed on the opposite side of the 1 st side, as viewed from above.

20. A polishing apparatus for chemical mechanical polishing of a wafer, comprising:

a fixed disc,

A plurality of polishing pads attached to the surface plate at intervals and having an upper surface as a polishing surface,

A holder for holding the wafer during polishing,

Activating the dresser on the plurality of polishing pads,

each of the plurality of polishing pads is subjected to chamfering or rounding at a corner portion when viewed from above.

21. A polishing apparatus for chemical mechanical polishing of a wafer, comprising:

a fixed disc,

A plurality of polishing pads adhered to the fixed plate and having an upper surface as a polishing surface,

A holder for holding the wafer during polishing,

Activating the dresser on the plurality of polishing pads,

in each of the polishing pads, a 1 st projecting portion is formed by projecting an upper portion at an upstream end portion as viewed in an operation direction during polishing,

in each of the polishing pads, a 2 nd projecting portion is formed at a downstream end portion in a polishing operation direction, the 2 nd projecting portion being formed so as to project from a lower portion and overlapping the 1 st projecting portion of the adjacent polishing pad.

22. The polishing apparatus as set forth in claim 21,

each of the polishing pads has a substantially rectangular shape in top view, and the 1 st protrusion is formed on the 1 st side and the 2 nd protrusion is formed on the opposite side of the 1 st side.

23. A polishing apparatus for chemical mechanical polishing of a wafer, comprising:

a fixed disc,

A plurality of polishing pads adhered to the fixed plate at intervals and having an upper surface as a polishing surface,

A holder for holding the wafer during polishing,

Activating the dresser on the plurality of polishing pads,

a binder is embedded between the plurality of polishing pads.

24. A polishing apparatus for chemical mechanical polishing of a wafer, comprising:

a fixed disc,

A plurality of polishing pads attached to the surface plate at intervals and having an upper surface as a polishing surface,

A holder for holding the wafer during polishing,

Activating the dresser on the plurality of polishing pads,

each of the plurality of polishing pads is provided with a through hole having an upper end of a peripheral edge portion formed in an oblique or rounded shape.

25. A method of polishing a wafer by using a polishing apparatus having a fixed plate and a plurality of polishing pads attached to the fixed plate and having an upper surface as a polishing surface,

the method comprises the following steps:

a step (a) of activating the upper surfaces of the plurality of polishing pads by a dresser,

A step (b) of polishing the wafer by pressing the wafer against the upper surface of the polishing pad while the surface plate is moved;

the polishing pad used in the steps (a) and (b) is subjected to chamfering or rounding at a portion of the upper end portion facing the adjacent polishing pad.

26. A method of polishing a wafer by using a polishing apparatus having a fixed plate and a plurality of polishing pads attached to the fixed plate and having an upper surface as a polishing surface,

the method comprises the following steps:

a step (a) of activating the upper surfaces of the plurality of polishing pads by a dresser,

A step (b) of polishing the wafer by pressing the wafer against the upper surface of the polishing pad while the surface plate is moved;

a1 st uneven portion and a 2 nd uneven portion that engages with the 1 st uneven portion of the adjacent polishing pad are formed at an end portion of the polishing pad used in the step (a) and the step (b).

27. A method of polishing a wafer by using a polishing apparatus having a fixed plate and a plurality of polishing pads attached to the fixed plate and having an upper surface as a polishing surface,

the method comprises the following steps:

a step (a) of activating the upper surfaces of the plurality of polishing pads by a dresser,

A step (b) of polishing the wafer by pressing the wafer against the upper surface of the polishing pad while the surface plate is moved;

the polishing pad used in the steps (a) and (b) is subjected to a beveling process or a rounding process on a part of the corner when viewed from above.

28. A method of polishing a wafer by using a polishing apparatus having a fixed plate and a plurality of polishing pads attached to the fixed plate and having an upper surface as a polishing surface,

the method comprises the following steps:

a step (a) of activating the upper surfaces of the plurality of polishing pads by a dresser,

A step (b) of polishing the wafer by pressing the wafer against the upper surface of the polishing pad while the surface plate is moved;

in the polishing pad used in the steps (a) and (b), a 1 st projecting portion projecting from an upper portion is formed at an upstream end portion, and a 2 nd projecting portion projecting from a lower portion is formed at a downstream end portion, which overlaps with the 1 st projecting portion of the adjacent polishing pad, as viewed in a traveling direction of the surface plate.

29. A method of polishing a wafer by using a polishing apparatus having a fixed plate and a plurality of polishing pads attached to the fixed plate at intervals and having an upper surface as a polishing surface,

the method comprises the following steps:

a step (a) of activating the upper surfaces of the plurality of polishing pads by a dresser,

A step (b) of polishing the wafer by pressing the wafer against the upper surface of the polishing pad while the surface plate is moved;

a binder is embedded between the plurality of polishing pads used in the steps (a) and (b).

30. A method of polishing a wafer by using a polishing apparatus having a fixed plate and a plurality of polishing pads attached to the fixed plate at intervals and having an upper surface as a polishing surface,

the method comprises the following steps:

a step (a) of activating the upper surfaces of the plurality of polishing pads by a dresser,

A step (b) of polishing the wafer by pressing the wafer against the upper surface of the polishing pad while the surface plate is moved;

the polishing pad used in the steps (a) and (b) is provided with a through hole having an upper end of a peripheral edge portion formed in an oblique or rounded shape.

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