JP2940614B2 - Wafer polishing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer polishing apparatus, and more particularly, to a chemical mechanical polishing method (CMP).
ical Polishing).

[0002]

2. Description of the Related Art A wafer polishing apparatus disclosed in Japanese Patent Application Laid-Open No. 8-339979 includes a holding head (carrier), a polishing pad (polishing cloth), and a seal member. A fluid supply path is formed in the holding head, and from this fluid supply path,
A pressurized fluid is supplied to a space surrounded by the holding head, the substrate (wafer), and the annular seal member, and the substrate is pressed against the polishing pad by the pressure of the pressurized fluid to perform polishing.

The fluid supply path is formed coaxially with the rotation axis of the holding head, and is set so that a pressurized fluid is ejected from the fluid supply path toward the center of the substrate.

[0004]

However, in the wafer polishing apparatus, since the fluid supply passage is formed at a position where the pressurized fluid is ejected toward the center of the substrate, the pressure of the pressurized fluid applied to the substrate is reduced. There is a disadvantage that the pressure is reduced as the distance from the center of the substrate increases. Thus, the wafer polishing apparatus has a drawback that the substrate cannot be polished with a uniform pressing force.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wafer polishing apparatus capable of polishing a wafer with a uniform pressing force.

[0006]

According to the present invention, in order to achieve the above object, a plurality of air ejection holes are formed in a carrier holding a wafer, and the plurality of air ejection holes are formed on a surface of the carrier facing the wafer. Is formed on the outer peripheral side of the carrier, ejects air from the plurality of air ejection holes, forms a pressure air layer between the carrier and the wafer while flowing the air out of the carrier, and is transmitted to the carrier. By transmitting the pressing force from the pressing means to the wafer via the pressure air layer, the wafer is pressed against the polishing cloth and polished.

According to the present invention, in order to achieve the above object, a plurality of air ejection holes are formed in a carrier for holding a wafer, and air is ejected from the plurality of air ejection holes to form a gap between the carrier and the wafer. A wafer polishing apparatus for forming a pressurized air layer on the wafer and transmitting the pressing force from the pressing means transmitted to the carrier to the wafer through the pressurized air layer, thereby pressing the wafer against a polishing cloth and polishing the air. The ejection hole communicates with a porous member provided on the carrier, and the porous member is provided at a position along an inside of a circle having a radius equal to the radius of the wafer.

Further, in order to achieve the above object, the present invention provides a wafer polishing apparatus for polishing a surface of a wafer by pressing the wafer against a rotating polishing cloth. A plurality of air ejection holes formed in the carrier, first pressing means for pressing the carrier toward the polishing pad, and the carrier and the wafer by ejecting air from the plurality of air ejection holes of the carrier. And a pressure air layer forming means for transmitting a pressing force from the first pressing means to the wafer through the pressure air layer, and surrounding the periphery of the wafer, from the carrier. A retainer ring that prevents the wafer from jumping out, and a polishing surface adjustment ring that surrounds the periphery of the wafer and is brought into contact with the polishing cloth together with the wafer. Wherein is the retainer ring and the second pressing means for pressing the said polished surface adjustment ring to the polishing cloth, a polishing amount detecting means for detecting the amount of polishing of the wafer, characterized in that it consists of.

According to the first aspect of the present invention, since the plurality of air ejection holes are formed on the outer peripheral side of the wafer facing surface of the carrier, the air pressure applied to the wafer becomes uniform over the entire surface of the wafer. Therefore, the wafer can be polished with a uniform pressing force. According to the second aspect of the present invention, the air ejected from the air ejection holes is guided by the air guide grooves formed in the carrier and is quickly supplied to the entire outer peripheral portion of the wafer, and this air forms a pressure air layer. It is formed. As described above, when air is supplied to the outer peripheral portion of the wafer through the air guide groove, the air pressure applied to the wafer becomes uniform over the entire surface of the wafer, so that the wafer can be polished with a uniform pressing force.

According to the third aspect of the present invention, each air ejection hole is communicated with the air guide groove. Therefore, the air guide grooves are formed in a number corresponding to the number of the air ejection holes. According to the fourth aspect of the present invention, the air guide groove includes the first air guide groove and the second air guide groove, and the first air guide groove is formed inside a circle having a radius equal to the maximum radius of the wafer. The second air guide groove is formed at a position along the inside of a circle having a radius equal to the minimum radius of the wafer.

Since the first air guide groove is formed at a position corresponding to the maximum radius of the wafer, when an orientation flat or a notch is formed on the wafer, the air pressure in that portion is reduced by reducing the air pressure. The wafer cannot be pressed uniformly. In order to solve the above problem, the second aspect of the present invention forms the second air guide groove at a position along the inside of a circle having a radius equal to the minimum radius of the wafer. The air guided by the second air guide groove is supplied to the entire periphery having a radius equal to the minimum radius of the wafer. When such a second air guide groove is formed, air can be supplied to the inside of the orientation flat or the notch, so that a wafer having the orientation flat or the notch can be polished with a uniform pressing force.

According to a fifth aspect of the present invention, the minimum radius of the wafer is defined as a length of a perpendicular line connecting the orientation flat from the center of the wafer. According to a sixth aspect of the present invention, the minimum radius of the wafer is defined as a length from the center of the wafer to the notch. According to a seventh aspect of the present invention, the first air guide groove and the second air guide groove are divided into a plurality of grooves. As described above, when the air guide grooves are divided and the air is supplied from each of the air guide grooves, a restoring force for restoring the inclined wafer to the original non-inclined state can be applied to the wafer. If the divided first and second air guide grooves are formed alternately, the restoring force can be efficiently applied to the wafer.

The invention according to claim 8 is the one in which a water injection hole for injecting water toward the wafer is formed in the carrier. As a result, the slurry and polishing debris attached to the wafer can be washed with water. In the case of a slurry, since it solidifies when dried, it is preferable to wash with water before drying, that is, immediately after polishing is completed. According to a ninth aspect of the present invention, the water injection hole is also used as the air injection hole.
This eliminates the need to separately form a water injection hole.

According to a tenth aspect of the present invention, a suction portion for suctioning the wafer by air is formed inside the second air guide groove, and when suctioning the wafer by the suction portion, air is discharged from the air ejection hole. This is to prevent dust outside the carrier from intruding between the suction portion and the wafer by being ejected.
According to an eleventh aspect of the present invention, the air ejection hole is connected to an air pump and a suction pump via a valve. According to the present invention, when the air pump side is opened by the valve and the suction pump side is closed, air can be ejected from the air ejection hole. Further, when the air pump side is closed and the suction pump side is opened by the valve, the air ejection hole functions as an air suction hole, so that the wafer can be sucked and held by the air ejection hole. This allows
According to the present invention, it is not necessary to separately provide a dedicated suction member.

According to a twelfth aspect of the present invention, an air ejection hole is communicated with a porous member provided on a carrier, and air is ejected through the porous member. Thus, even if air is jetted through the porous member, air can be uniformly supplied to the peripheral portion of the wafer. According to the thirteenth aspect of the present invention, air is blown out from the plurality of air blowout holes formed in the carrier to form a pressure air layer between the carrier and the wafer, and the pressure air layer is formed through the pressure air layer. 1
The pressing force from the pressing means is transmitted to the wafer, and the wafer is pressed against the polishing pad. Thereby, the present invention can be applied to the first method even if there is foreign matter such as polishing dust between the carrier and the wafer.
Since the pressing force from the pressing means can be transmitted uniformly to the entire surface of the wafer, the entire surface of the wafer can be uniformly polished.

Further, according to the twelfth aspect of the present invention, the wafer is prevented from jumping out of the carrier by retainer ring. Further, the invention according to claim 12 is provided with a polishing surface adjusting ring that comes into contact with the polishing cloth together with the wafer, and the pressing force of the polishing surface adjusting ring against the polishing cloth is adjusted by the second pressing means, so that the periphery of the wafer is The swelling of the polishing cloth is suppressed, and the pressure applied to the wafer from the polishing cloth is made uniform. Therefore, the present invention can uniformly polish the entire surface of the wafer. According to the twelfth aspect of the present invention, since the amount of polishing of the wafer during polishing is detected by the detecting means, the end point of the amount of polishing can be accurately detected.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a wafer polishing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of a wafer polishing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the wafer polishing apparatus 10 mainly includes a polishing platen 12 and a wafer holding head 14. The polishing platen 12 is formed in a disk shape, and a polishing cloth 16 is provided on an upper surface thereof. A spindle 18 is provided below the polishing platen 12.
The spindle 18 is connected to an output shaft (not shown) of the motor 20. When the motor 20 is driven, the polishing platen 12 rotates in the direction of arrow A, and slurry is supplied from a nozzle (not shown) onto the polishing cloth 16 of the rotating polishing platen 12. The wafer holding head 14
Is vertically movable by a lifting device (not shown), and is moved upward when a wafer to be polished is set on the wafer holding head 14. When polishing the wafer, the wafer holding head 14 is moved down and pressed against the polishing pad 16.

FIG. 2 is a longitudinal sectional view of the wafer holding head 14. The wafer holding head 14 shown in FIG. 1 includes a head body 22, a carrier 24, a guide ring 26, a polishing surface adjustment ring 28, a rubber sheet 30, and the like. The head body 22 is formed in a disk shape,
The motor 2 is rotated in the direction of arrow B by a motor (not shown) connected to the motor 2. The air supply path 3 is provided in the head body 22.
4 and 36 are formed. The air supply path 34 extends outside the wafer holding head 14 as shown by a two-dot chain line in FIG. 2 and has a regulator (R) 38A.
To an air pump (AP) 40. The air supply path 36 is connected to an air pump 40 via a regulator 38B.

The carrier 24 is formed in a substantially columnar shape and is arranged coaxially with the head main body 22 below the head main body 22. Further, a concave portion 25 is provided on the lower surface of the carrier 24.
Is formed, and a porous plate (sucking portion) 42 having air permeability is accommodated in the concave portion 25. An air chamber 27 is formed above the porous plate 42, and an air suction path 44 formed in the carrier 24 communicates with the air chamber 27. The air suction path 44 extends outside the wafer holding head 14 as shown by a two-dot chain line in FIG. 2 and is connected to a suction pump (SP) 46.
Therefore, when the suction pump 46 is driven, the wafer 50 is sucked by the porous plate 42 and held by suction on the lower surface of the porous plate 42. The porous plate 42 has a number of air passages therein, and for example, a porous plate made of a sintered body of a ceramic material is used.

On the bottom surface of the carrier 24, a number of air ejection holes 48 are formed (only two are shown in FIG. 2). Are formed at predetermined intervals as shown in FIG.
Are extended outside the wafer holding head 14 as shown by a two-dot chain line in FIG. 2, and connected to the pump 40 via a regulator 38C. Therefore, the compressed air from the pump 40 flows through the porous plate 42 and the wafer 50 through the air ejection holes 48, 48.
Is blown out into the air chamber 51. Accordingly, a pressure air layer is formed in the air chamber 51, and the pressing force of the carrier 24 is transmitted to the wafer 50 via the pressure air layer. The wafer 50 is pressed against the polishing pad 16 by the pressing force transmitted through the pressure air layer. The air blown out from the air blowout holes 48, 48,.
Air is exhausted from an exhaust hole (not shown) formed in the polishing surface adjusting ring 28.

The air ejection holes 48 are connected to air guide grooves 49 formed on the bottom surface of the carrier, as shown in FIGS. The air guide groove 49 is formed at a predetermined depth and at a position along the inside of a circle having a radius equal to the radius of the wafer 50. Therefore, the air ejected from the air ejection holes 48, 48.
0 is supplied to the entire outer peripheral portion. This air forms the above-described pressure air layer. When air is supplied to the outer peripheral portion of the wafer 50 through the air guide groove 49, the air pressure applied to the wafer 50 becomes uniform over the entire surface of the wafer as shown in FIG. Therefore, the wafer 50 can be polished with a uniform pressing force.

In FIG. 2, a large number of ejection holes 52, 52... (Only two are shown in FIG. 2) are formed in the carrier 24. Are formed at predetermined intervals as shown in FIG. Are extended outside the wafer holding head 14 as shown by a two-dot chain line in FIG.
It is branched in two directions via the line 4. An air pump 40 is connected to one branch through a regulator 38D, and a water pump (WP: water) is connected to the other branch.
pump) 56 is connected. Therefore, when the flow path on the side of the air pump 40 is opened by the valve 54 and the flow path on the side of the water pump 56 is closed, compressed air from the air pump 40 is supplied to the air chamber 51 through the ejection holes 52, 52. Is done. Further, the valve 54 is switched so that the air pump 4
When the flow path on the 0 side is closed and the flow path on the water pump 56 is opened, water from the water pump 56 is discharged.
2 to the air chamber 51.

The ejection holes 52 are communicated with guide grooves 53 formed on the bottom surface of the carrier, as shown in FIGS. The guide groove 53 is formed at a predetermined depth, and the guide groove 4 is formed outside the guide groove 49.
9 is formed on a concentric circle. Therefore, the ejection hole 5
The water jetted from 2, 52,... Is guided by the guide groove 53 and supplied toward the outer peripheral edge of the wafer 50. When the water is supplied in this manner, the slurry and polishing debris attached to the edge of the wafer 50 can be washed with water.
Further, when air is blown out from the blowout holes 52, 52, the water-washed wafer 50 can be dried.

In FIG. 2, one rubber sheet 30 is disposed between the carrier 24 and the head main body 22. This rubber sheet 30 is formed in a disk shape with a uniform thickness. The rubber sheet 30 is fixed to the lower surface of the head main body 22 by an annular stopper 58, and the rubber sheet 3
0 is the central portion 30A and the outer peripheral portion 30B with respect to the stopper 58.
And it is divided into two. The central portion 30A of the rubber sheet 30 presses the carrier 24, and the outer peripheral portion 30B presses the polishing surface adjustment ring 28.

The rubber sheet 3 is provided below the head body 22.
A space 60 which is hermetically sealed by the central portion 30 </ b> A and the stopper 58 is formed. The air supply path 36 communicates with the space 60. Therefore, when compressed air is supplied from the air supply path 36 to the space 60, the central portion 30A of the rubber sheet 30 is elastically deformed by air pressure and presses the upper surface of the carrier 24. Thereby, a pressing force of the wafer 50 against the polishing pad 16 can be obtained. Further, if the air pressure is adjusted by the regulator 38B, the pressing force (polishing pressure) of the wafer 50 can be controlled.

The guide ring 26 is formed in a cylindrical shape, and is disposed coaxially with the head main body 22 below the head main body 22. In addition, the guide ring 26 is attached to the rubber sheet 3.
0 is fixed to the head main body 22. A polishing surface adjusting ring 28 is disposed between the guide ring 26 and the carrier 24. A retainer ring 62 for preventing the wafer 50 from jumping out is attached to the lower inner peripheral portion of the polishing surface adjusting ring 28.

An annular space 64 is formed in the lower outer peripheral portion of the head main body 22 so as to be sealed by the outer peripheral portion 30B of the head main body 22 and the rubber sheet 30 and the like. This space 6
4 communicates with the air supply path 34. Therefore, when compressed air is supplied from the air supply path 34 to the space 64, the outer peripheral portion 30B of the rubber sheet 30 is elastically deformed by air pressure and presses the annular upper surface of the polishing surface adjustment ring 28. As a result, the annular lower surface of the polishing surface adjusting ring 28 is
Pressed to 6. The pressing force of the polishing surface adjusting ring 28 can be controlled by adjusting the air pressure with the regulator 38A.

In FIG. 2, the wafer holding head 1
4 is provided with a detection device for detecting the polishing amount of the wafer 50. This detecting device comprises a core 66 and a bobbin 68.
And a non-contact type sensor 72, 72, 7
2 and these sensors 70, 72,
CPU for performing arithmetic processing on the detection values detected at 72, 72
(FIG. 5) 74 is provided outside the wafer holding head 14.

The bobbin 68 of the sensor 70 is attached to the tip of an arm 76 extending from the inner surface of the polishing surface adjusting ring 28 in the direction of the rotation axis of the wafer holding head 14. The core 66 of the sensor 70 is provided at a position where the center axis of the core 66 is coaxial with the rotation axis of the wafer holding head 14. The sensor 70 can detect the amount of vertical movement of the carrier 24 with respect to the lower surface of the polishing surface adjustment ring 28, that is, with respect to the polishing surface of the wafer 50. Note that a groove 78 for inserting the arm 76 is formed in the carrier 24.

Although the polishing amount of the wafer 50 can be substantially detected by the sensor 70, in the present embodiment, the detection value detected by the sensor 70 is
The amount of polishing of the wafer 50 is accurately obtained by correcting with the detection value detected at 72. The sensor 72 is a non-contact sensor such as a capacitance sensor, and its detection surface 72A is arranged flush with the lower surface of the porous plate 42. By detecting the distance from the upper surface of the wafer 50, The amount of change in the thickness of the pressure air layer is detected.

The CPU 74 for controlling the wafer polishing apparatus shown in FIG. 5 determines the amount of change in the thickness of the pressure air layer detected by the sensors 72, 72, 72 based on the amount of change in the carrier 24 detected by the sensor 70. Is added to calculate the polishing amount of the wafer 50. That is, the CPU 74 calculates the polishing amount of the wafer 50 from the fluctuation amount with respect to the reference value stored in the RAM 75 in advance. For example, sensor 7
The fluctuation amount detected at 0 is T1, and the sensors 72, 72, 7
If the average value of the fluctuation amounts detected in Step 2 is T2, the polishing amount of the wafer 50 at that time is calculated by T1 + T2. Further, the amount of fluctuation from the sensor 70 is T1, and the sensors 72, 7
If the average value of the fluctuation amounts from 2, 72 is 0, the polishing amount of the wafer 50 at that time is calculated by T1 + 0. Further, the fluctuation amount from the sensor 70 is T1, and the sensors 72, 72, 7
If the average value of the variation from 2 is -T2, the polishing amount of the wafer 50 at that time is calculated by T1-T2. As described above, in the present embodiment, the sensors 70 and 72 are provided to calculate the polishing amount from the two fluctuation amounts, so that the polishing amount of the wafer 50 can be accurately measured. Also,
Since the thickness of the processed wafer is a known thickness, the polishing surface adjusting ring 2 for the wafer polishing surface and the polishing pad 16 is used.
The relationship with the contact position 8 can also be detected. Therefore, the pressing of the polishing surface adjusting ring 28 can be accurately adjusted.

Next, the operation of the wafer polishing apparatus 10 configured as described above will be described. First, after raising the wafer holding head 14, the suction pump 46 is driven to suck and hold the wafer 50 to be polished on the porous plate 42. Before driving the suction pump 46, air is weakly blown out from the air blowing holes 48 and 52 to form an air curtain around the porous plate 42, and dust outside the carrier causes the porous plate 42 and the wafer 50 To prevent intrusion between

Next, the wafer holding head 14 is lowered, and the lowering movement is stopped at a position where the contact surface of the polishing surface adjusting ring 28 is in contact with the polishing pad 16. Then, the suction pump 46 is stopped to release the suction of the wafer 50, and the wafer 50 is placed on the polishing pad 16. Next, when the air pump 40 is driven to eject compressed air from the air ejection holes 48, the compressed air is guided by the air guide grooves 49 and is quickly supplied to the entire outer peripheral portion of the wafer 50,
This air forms a pressure air layer in the air chamber 51. Thus, when air is supplied through the air guide groove 49, the air pressure applied to the wafer 50 becomes uniform over the entire surface of the wafer as shown in FIG. 4, so that the wafer 50 can be polished with a uniform pressing force. it can.

Next, the compressed air from the air pump 40 is
The air is supplied to the space 60 via the air supply path 36, and the center portion 30 </ b> A of the rubber sheet 30 is elastically deformed by internal air pressure to press the carrier 24. Thereby, the wafer 50
Is pressed against the polishing pad 16. Then, the pressure of the wafer 50 against the polishing pad 16 is kept constant by adjusting the air pressure by the regulator 38B. This pressing force is set by the external input device 80 shown in FIG.

Next, compressed air from the air pump 40 is supplied to the space 64 through the air supply path 34,
The outer peripheral portion 30B is elastically deformed by the internal air pressure to press the polishing surface adjusting ring 28. As a result, the lower surface of the polishing surface adjustment ring 28 and the lower surface of the retainer ring 62 are simultaneously pressed against the polishing pad 16. Thereafter, the polishing platen 12
And the wafer holding head 14 is rotated so that the wafer 50
Start polishing.

Then, the sensors 70, 72, 72, 72,
The CPU 74 calculates the polishing amount of the wafer 50 during polishing, and outputs a polishing end signal when the calculated polishing amount of the wafer 50 reaches a preset polishing target value. Stop. Thus, polishing of one wafer 50 is completed. When the polishing of the wafer 50 is completed, water is sprayed from the ejection holes 52, 52, and the slurry and polishing debris attached to the wafer 50 are washed with water. After the cleaning, air is injected from the ejection holes 52, 52, and so on, to dry the wafer 50. Thus, the polishing process for one wafer 50 is completed. When polishing the second and subsequent wafers 50,
The above steps may be repeated.

As described above, in the present embodiment, the air guide groove 49 is formed at a position corresponding to the outer peripheral portion of the wafer 50, and compressed air is supplied through the air guide groove 49. The wafer 50 can be polished with a uniform pressing force. Even if the air guide groove 49 is not formed, the same effect can be obtained if the air ejection holes 48 are formed densely along the position corresponding to the outer peripheral portion of the wafer 50.

FIG. 6 is a bottom view showing a carrier 90 applied to the wafer holding head 14 according to a second embodiment. A plurality of first air guide grooves 92, 92, and a plurality of second air guide grooves 94, 94,... Are formed on the bottom surface of the carrier 90 shown in FIG. Each of the first air guide grooves 92 is connected to an air ejection hole 93 at a central portion thereof, and the second air guide grooves 94 are similarly connected to an air ejection hole 95. Also, the first air guide grooves 92, 92,... And the second air guide grooves 94, 94,.

The first air guide grooves 92 are formed at positions along the inside of a circle having a radius equal to the maximum radius of the wafer. Therefore, the air ejected from the air ejection holes 93 is guided by the first air guide grooves 92, 92, and is quickly supplied to the entire outer peripheral portion of the wafer.
This air forms a pressure air layer. Thereby, the wafer can be polished with a uniform pressing force.

By the way, the first air guide grooves 92, 92,...
Is formed at a position corresponding to the maximum radius of the wafer, so if an orientation flat or notch is formed on the wafer, the air pressure in that part will be reduced and it will not be possible to uniformly press the wafer .
Therefore, the carrier 90 includes the second air guide groove 9 at a position along the inside of a circle having the minimum radius of the wafer.
4, 94 ... are formed. Therefore, the air ejection holes 9
When air is ejected from 5, 95..., The air is guided by the second air guide grooves 94, and is supplied to the entire periphery having a radius equal to the minimum radius of the wafer, and the air forms a pressure air layer. . Such a second air guide groove 9
By forming 4, 94..., Air can be supplied to the inside of an orientation flat (OF) shown by a two-dot chain line in FIG. 7 and a notch shown by a two-dot chain line in FIG. Even with 50, polishing can be performed with a uniform pressing force.

The aforementioned minimum radius of the wafer is the length of a perpendicular line connecting the orientation flat from the center of the wafer, and in the case of a notch, is the length from the center of the wafer to the notch. On the other hand, in the carrier 90 shown in FIG. 6, since the first air guide groove 92 and the second air guide groove 94 are divided into a plurality of grooves, the respective air guide grooves 92, 92, 94, 94,. When air is supplied from the wafer, a restoring force for restoring the inclined wafer to the original non-inclined state can be applied to the wafer. Also,
Since the divided first air guide grooves 92 are alternately formed with the second air guide grooves 94, the restoring force can be efficiently applied to the wafer.

FIG. 9 is a longitudinal sectional view of the wafer holding head 114 of the second embodiment. The same or similar members as those of the wafer holding head 14 of the first embodiment shown in FIG. 2 are the same. And the description thereof is omitted. The bottom surface of the carrier 124 of the wafer holding head 114 is located at a position facing the peripheral portion of the wafer 50 as shown in FIG.
The annular porous member 96 shown in FIG. As shown in FIG. 9, the porous member 96 is
It is connected to 2. Therefore, the air ejection holes 48, 5
The air from 2 is ejected toward the peripheral portion of the wafer 50 through the porous member 96. Even when the porous member 96 is applied instead of the air guide groove as in the wafer holding head 114 of the present embodiment, air can be uniformly supplied to the peripheral portion of the wafer 50.

FIG. 11 is a longitudinal sectional view of the wafer holding head 214 of the third embodiment. The same or similar members as those of the wafer holding head 14 of the first embodiment shown in FIG. 2 are the same. And the description thereof is omitted. The wafer holding head 214 includes the carrier 22
4 is formed by connecting an air ejection hole 48 formed to the air pump 40 and the suction pump 46 via a valve 100. Accordingly, when the flow path on the air pump 40 side is opened by the valve 100 and the flow path on the suction pump 46 side is closed, air from the air pump 40 is released from the air ejection holes 4.
8 can squirt. On the other hand, the valve 100
Close the flow path on the side of the air pump 40 with the suction pump 4
When the flow path on the sixth side is opened, the air ejection hole 48 functions as an air suction hole, and the air ejection hole 48 can hold the wafer 50 by suction. As described above, when the air ejection holes 48 are used for suction, it is not necessary to provide a dedicated suction member (porous member) for wafer suction on the carrier 224. Similarly, the air ejection hole 52 may be connected to the air pump 40 and the suction pump 46 via a valve, and the air ejection hole 52 may be switched between air ejection and wafer suction.

[0044]

As described above, according to the wafer polishing apparatus of the present invention, since a plurality of air ejection holes are formed on the outer peripheral side of the wafer facing surface of the carrier, the wafer is polished with a uniform pressing force. be able to. Further, according to the present invention, the air ejected from the air ejection holes is supplied to the outer peripheral portion of the wafer through the first air guide groove formed at a position corresponding to the maximum radius of the wafer, so that the wafer can be uniformly formed. Polishing can be performed with an appropriate pressing force.

Further, according to the present invention, a second air guide groove is formed at a position along the inside of a circle having a radius equal to the minimum radius of the wafer, and air is supplied to the peripheral portion of the wafer via the second air guide groove. Since the jetting is performed, even a wafer having an orientation flat or a notch can be polished with a uniform pressing force.

[Brief description of the drawings]

FIG. 1 is an overall structural diagram of a wafer polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a wafer holding head applied to the wafer polishing apparatus of FIG.

FIG. 3 is a bottom view of the carrier according to the first embodiment.

FIG. 4 is an explanatory diagram schematically showing a distribution of air pressure applied to a wafer.

FIG. 5 is a block diagram showing a control system of the wafer polishing apparatus of FIG. 1;

FIG. 6 is a bottom view of the carrier according to the second embodiment.

7 is a diagram showing the relationship between the carrier shown in FIG. 6 and a wafer with an orientation flat.

FIG. 8 is a diagram showing the relationship between the carrier and the notched wafer shown in FIG. 6;

FIG. 9 is a longitudinal sectional view of a wafer holding head according to a second embodiment.

FIG. 10 is a bottom view of the carrier of the wafer holding head shown in FIG. 9;

FIG. 11 is a longitudinal sectional view of a wafer holding head according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Wafer polishing apparatus 12 ... Polishing surface plate 14, 114, 214 ... Wafer holding head 16 ... Polishing cloth 24, 90 ... Carrier 28 ... Polishing surface adjustment ring 49, 53, 92, 94 ... Guide groove 50 ... Wafer 62 ... Retainer Ring 96: porous member 100: valve

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-150558 (JP, A) JP-A-9-66429 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B24B 37/00 B24B 37/04 H01L 21/304 622

Claims (13)

(57) [Claims] A carrier holding a wafer is provided with a plurality of air ejection holes, and the plurality of air ejection holes are formed in the carrier.
Formed on the outer peripheral side of the wafer facing surface, and ejecting air from said plurality of air ejection holes, before the air
While the outflow to the outside of the serial carrier to form a pressure air layer between the carrier and the wafer, by transmitting the pressing force from the pressing means is transmitted to the carrier to the wafer through the pressure air layer, the A wafer polishing apparatus for polishing a wafer by pressing the wafer against a polishing cloth. 2. The wafer polishing apparatus according to claim 1, wherein the plurality of air ejection holes communicate with each other through an air guide groove formed on a wafer facing surface of the carrier. 3. A plurality of air ejection holes are communicated with an air guide groove for each air ejection hole, and the air guide grooves are formed on a wafer facing surface of the carrier. 2. The wafer polishing apparatus according to 1. 4. The air guide groove comprises a first air guide groove and a second air guide groove, and the first air guide groove is located at a position along an inside of a circle having a radius equal to the maximum radius of the wafer. 4. The wafer polishing apparatus according to claim 3, wherein the second air guide groove is formed at a position along an inside of a circle having a radius equal to a minimum radius of the wafer. 5. The wafer according to claim 4, wherein the minimum radius of the wafer is a length of a perpendicular line connecting an orientation flat formed on the wafer from the center of the wafer.
A wafer polishing apparatus as described in the above. 6. The wafer polishing apparatus according to claim 4, wherein the minimum radius of the wafer is a length of a line connecting a notch formed on the wafer from the center of the wafer. 7. The first air guide groove and the second air guide groove are divided into a plurality of grooves, and the divided first air guide groove and the second air guide groove are formed alternately. 5. The wafer polishing apparatus according to claim 4, wherein: 8. A water injection hole for injecting water toward the wafer is formed in the carrier, and the slurry attached to the polished wafer is removed by the water injected from the water injection hole. The wafer polishing apparatus according to claim 1, wherein 9. The wafer polishing apparatus according to claim 8, wherein said water jetting hole is also used as said air jetting hole. 10. A suction portion for suctioning a wafer by air is formed inside the second air guide groove of the carrier,
5. The method according to claim 4, wherein when the wafer is suctioned by the suction portion, air is blown out from the air blowout hole to prevent dust outside the carrier from entering between the suction portion and the wafer. A wafer polishing apparatus as described in the above. Wherein said air ejection holes are communicated with the air pump and the suction pump via a valve, closing the suction pump side open air pump side by the valve,
2. The air ejection hole functions as an air suction hole to suck and hold a wafer when air is ejected from the air ejection hole and the air pump side is closed and the suction pump side is opened by the valve. Wafer polishing equipment. 12. A plurality of air ejection holes are formed in a carrier holding a wafer, and air is ejected from the plurality of air ejection holes to form a pressure air layer between the carrier and the wafer.
In a wafer polishing apparatus for polishing a wafer by pressing the wafer against a polishing cloth by transmitting a pressing force from a pressing means transmitted to a carrier to the wafer through the pressure air layer, the air ejection hole is provided in the carrier. A wafer polishing apparatus, wherein the porous member is provided at a position along an inside of a circle having a radius equal to the radius of the wafer. 13. A wafer polishing apparatus for polishing a surface of a wafer by pressing the wafer against a rotating polishing cloth, wherein the carrier holds the wafer and has a plurality of air ejection holes formed on an outer peripheral side of a wafer facing surface. A first pressing unit for pressing the carrier toward the polishing cloth; and forming a pressure air layer between the carrier and the wafer by blowing air from the plurality of air blowing holes of the carrier. Pressure air layer forming means for transmitting the pressing force from the first pressing means to the wafer via the pressure air layer; a retainer ring surrounding the periphery of the wafer and preventing the wafer from jumping out of the carrier; A polishing surface adjustment ring that surrounds the periphery of a wafer and is brought into contact with the polishing cloth together with the wafer; and the retainer ring and the polishing surface adjustment. Wafer polishing apparatus, wherein a second pressing means for pressing the ring to the polishing cloth, a polishing amount detecting means for detecting the amount of polishing of the wafer, in that it consists of.