JP2002217147A - Method and apparatus for recovering wafer for wafer polishing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easy wafer recovery method for a wafer polishing apparatus after a wafer polishing is completed, and the apparatus. SOLUTION: After a wafer polishing is completed, the wafer is protruded a predetermined length from the peripheral edge of a polishing pad 20 by sliding the wafer W along the polishing pad 20. Then a fluid is emitted into the clearance between the protruded wafer W and the polishing pad 20 from a wafer separation nozzle 18. The emitted liquid gets into the clearance between the wafer W and the polishing pad 20, which uplifts the wafer from the polishing pad 20 to separate the wafer. Consequently, the wafer can be efficiently withdrawn from the polishing pad 20 without adding stiff force to the wafer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method and an apparatus for recovering a wafer by a wafer polishing apparatus for polishing a wafer by chemical mechanical polishing (CMP).

[0002]

2. Description of the Related Art Wafer polishing by CMP is performed by pressing a wafer against a rotating polishing pad and supplying a mechanochemical abrasive (slurry) between the wafer and the polishing pad.

By the way, the wafer is pressed against the polishing pad by pressing the upper surface against the carrier during polishing. When the wafer is polished while pressing the upper surface with the carrier as described above, the surface tension of the slurry, the cleaning liquid and the like is increased. As a result, the wafer sticks to the polishing pad, and there is a disadvantage that the wafer cannot be collected from the polishing pad after the polishing is completed.

Therefore, conventionally, Japanese Patent Application Laid-Open No. H10-26160
As disclosed in Japanese Patent Publication No. 1 (1993), a method of injecting an aqueous solution containing carbon dioxide gas onto a polishing pad and separating and recovering the wafer from the polishing pad by the foaming action, or sliding the wafer from the periphery of the polishing pad A method has been employed in which the contact area is reduced by extruding to recover.

[0005]

However, the method of separating the wafer from the polishing pad by the action of bubbling of carbon dioxide gas has a disadvantage that the aqueous solution containing carbon dioxide gas is jetted from the outside of the retainer ring, resulting in poor efficiency. There is. In addition, there is a drawback in that a separate facility for supplying an aqueous solution containing carbon dioxide is required, and the apparatus becomes large-scale.

On the other hand, in the method of recovering a wafer by sliding it, when the sticking force of the wafer is strong, the amount of pushing the wafer must be increased. However, when the amount of pushing the wafer is increased, the carrier is inclined ( Generally, the carrier is supported so as to be tilted.) There is a drawback that the wafer cannot be collected substantially.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wafer collecting method and apparatus of a wafer polishing apparatus which can easily collect a wafer after polishing is completed.

[0008]

According to the present invention, in order to achieve the above object, the wafer is pressed against a polishing pad by pressing the upper surface of the wafer with a carrier, and the upper surface of the polished wafer is polished. In a wafer recovery method of a wafer polishing apparatus for recovering a wafer from a polishing pad by suctioning with a carrier, a wafer after polishing is suctioned with the carrier, and the wafer is slid along the polishing pad via the carrier. By projecting the wafer from the periphery of the polishing pad by a predetermined amount, and ejecting a fluid between the projected wafer and the polishing pad, the wafer is separated from the polishing pad and collected by the carrier. The present invention provides a method for collecting a wafer in a wafer polishing apparatus, comprising:

In the recovery of the wafer according to the present invention, first, the polished wafer is slid along the polishing pad, so that the wafer is projected from the periphery of the polishing pad by a predetermined amount. Next, a fluid is injected between the protruded wafer and the polishing pad. The fluid thus ejected enters between the polishing pad and the wafer from the peripheral portion of the polishing pad, lifts the wafer from the polishing pad, and separates the wafer from the polishing pad. Since the peeled wafer is held by suction on the carrier,
The wafer is lifted by a carrier and collected from the polishing pad. According to this method, the fluid can be directly jetted to the boundary portion between the wafer and the polishing pad, so that the wafer can be efficiently separated from the polishing pad. Further, the amount of the wafer protruding from the peripheral edge of the polishing pad is sufficient within a range in which the carrier does not tilt, and therefore, it is not practically impossible to collect the wafer.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method and an apparatus for recovering a wafer in a wafer polishing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a side view showing the overall configuration of a wafer polishing apparatus 10. As shown in FIG. 1, the wafer polishing apparatus 10 mainly includes a polishing platen 12, a wafer holding head 14, a head moving mechanism 16, and a wafer peeling spray nozzle 18.

The polishing platen 12 is formed in a disk shape, and a rotating shaft 12A is connected to the center of the lower surface thereof. A motor (not shown) is connected to the rotating shaft 12A, and by driving this motor, the polishing platen 12 rotates. A polishing pad 20 is attached to an upper surface of the polishing platen 12, and a slurry is supplied from the slurry supply nozzle 21 onto the polishing pad 20.

As shown in FIG. 2, the wafer holding head 14 mainly comprises a head body 22, a carrier 24, a carrier driving mechanism 26, a carrier pressing mechanism 28, a retainer ring 30, and a retainer ring pressing mechanism 32.

The head body 22 is formed in a disk shape, and a rotation shaft 22A is connected to the center of the upper surface. Rotary shaft 22A
Is supported by the bearing unit 35 as shown in FIG.
It is driven and rotated by a motor 36 provided in the bearing unit 35.

The carrier 24 is formed in a disk shape and is arranged at the lower center of the head body 22. A plurality of grooves 38, 38,...
Inside, a suction / blowing port 40 is formed. In addition, an air flow path 42 formed inside the carrier 24 is communicated with the suction / blow-out port 40, and the air flow path 42 is connected to an intake pump and an air supply pump via an air pipe (not shown). . Then, by switching the connection between the suction pump and the air supply pump, air is sucked or blown out from each suction / blowing port 40.

The carrier driving mechanism 26 includes a drive shaft 44, a drive plate 46, and a drive pin 48. The drive shaft 44 is formed in a cylindrical shape,
The upper end is connected to the center of the lower surface of the head body 22.
The drive plate 46 is connected to a lower end of the drive shaft 44. The drive plate 46 is formed in a disk shape, and is fitted in a circular concave portion 50 formed in the center of the upper surface of the carrier 24. A drive pin 48 is provided in the recess 50 and is fitted into a pin hole (not shown) formed in the drive plate 46.

According to the carrier driving mechanism 26 configured as described above, when the head main body 22 is rotated, the rotation is transmitted to the drive plate 4 via the drive shaft 44.
6 is transmitted. And the drive plate 46
Is transmitted to the carrier 24 via the drive pin 48, and the carrier 24 rotates.

The carrier pressing mechanism 28 includes a carrier airbag 52 and a carrier pressing member 54.
The carrier airbag 52 is formed in a donut shape and is arranged on the outer periphery of the lower surface of the head body 22. The airbag carrier 52 is formed of a rubber sheet, expanded in the air intake and exhaust to be supplied from the air supply means (not shown) contracts. The carrier pressing member 54 is formed in a cylindrical shape, and the lower end thereof is fixed to the outer peripheral portion of the upper surface of the carrier 24.

According to the carrier pressing mechanism 28 configured as described above, when the carrier airbag 52 is inflated, the carrier pressing member 54 is moved by the carrier airbag 5.
2 is pressed downward. As a result, the carrier 24 to which the carrier pressing member 54 is fixed is pressed downward.

The retainer ring 30 is formed in a ring shape and is arranged on the outer periphery of the carrier 24. The retainer ring 30 is attached to a retainer ring holder 56 arranged on the outer periphery of the carrier 24.

The retainer ring holder 56 is formed in a ring shape, and has an annular concave portion 56A formed on the lower surface thereof.
The retainer ring 30 is attached to the retainer ring holder 56 by fitting into the recess 56A. The retainer ring 30 attached to the retainer ring holder 56 is fixed by being screwed at a plurality of locations with bolts 58, 58,.

The retainer ring holder 56 to which the retainer ring 30 is attached is detachably attached to the attachment ring 60 via a snap ring 62. A groove 62A is formed in the inner peripheral portion of the snap ring 62. A flange portion 56B formed on the outer periphery of the upper end portion of the retainer ring holder 56 and a flange portion 60A formed on the outer periphery of the lower end portion of the mounting ring 60 are formed in the groove 62A. And the retainer ring holder 56 is attached to the mounting ring 6.
0 is attached.

The retainer ring holder 56 has a flange portion 56C formed on the inner peripheral portion thereof, and the flange portion 24A formed on the outer peripheral portion of the carrier 24 is mounted on the flange portion 56C.

The retainer ring pressing mechanism 32 includes a retainer ring airbag 64 and a retainer ring pressing member 66. The retainer ring airbag 64 is formed in a donut shape, and is disposed at the center of the lower surface of the head body 22. The retainer ring airbag 64 is formed of a rubber sheet, and expands and contracts by intake and exhaust of air supplied from air supply means (not shown). The retainer ring pressing member 66 is formed in a substantially cylindrical shape, and its lower end is fixed to the upper surface of the mounting ring 60.

According to the retainer ring pressing mechanism 32 configured as described above, when the retainer ring airbag 64 is inflated, the retainer ring pressing member 66 is pressed.
Is pressed downward by the retainer ring airbag 64. As a result, the retaining member pressing member 6
The retainer ring 30 is pressed downward via the mounting ring 60 to which the fixing member 6 is fixed and the retainer ring holder 56.

The protective sheet 34 is formed in a circular shape and has a plurality of ventilation holes 68, 68,... The protective sheet 34 is held between its retainer ring 30 and the retainer ring holder 56 at its peripheral edge, so that the retainer ring 30
It is stretched inside.

The protective sheet 34 stretched under the carrier 24 as described above is formed by the suction and suction formed on the carrier 24.
When air is blown out from the outlet 40, an air layer is formed between the air outlet 40 and the lower surface of the carrier 24. And the protection sheet 34
Presses the wafer W against the polishing pad 20 by being pressed by the air layer. In addition, the protection sheet 34
When air is sucked from the suction / blowing port 40, the air holes 6
The wafer W is sucked and held through 8, 68,.

The head moving mechanism 16 moves the wafer holding head 14 vertically and horizontally. As shown in FIG. 1, the bearing unit 35 that supports the rotating shaft 22 </ b> A of the head body 22 is slidably provided on a guide rail 72 laid on a moving plate 70. The moving plate 70 is provided with an elevating device (not shown) (for example, a cylinder or a feed screw). The moving plate 70 is fixed to a carriage 74, and the carriage 74 is slidably provided on a guide rail 78 laid on a ceiling frame 76. The carriage 74 travels on the guide rail 78 by being driven by a horizontal driving device (for example, a cylinder, a feed screw, or the like) (not shown). Move horizontally along.

The head moving mechanism 1 configured as described above
According to 6, the lifting unit (not shown) is driven to move the bearing unit 35 up and down, whereby the wafer holding head 14 moves vertically with respect to the polishing platen 12. By driving a horizontal driving device (not shown), the moving plate 70 moves horizontally, whereby the wafer holding head 14 moves horizontally along the polishing surface of the polishing platen 12.

The wafer peeling spray nozzle 18 is provided with a wafer W projecting a predetermined amount from the peripheral portion of the polishing pad 20.
Liquid (for example, water) at the boundary between
Is ejected, the wafer W attached to the polishing pad 20 is separated from the polishing pad 20. As shown in FIG. 1, the wafer peeling spray nozzle 18 is disposed near the outer peripheral portion of the polishing platen 12 and is attached at a predetermined angle to an angle 80 fixed to the apparatus main body frame. Then, the liquid is supplied from a liquid supply device (not shown), and the liquid is ejected from the tip nozzle portion.

The wafer W held by the carrier 24 is
By horizontally moving the wafer holding head 14,
It slides on the polishing pad 20, thereby protruding a predetermined amount from the periphery of the polishing pad 20. Then, water is sprayed from the wafer peeling spray nozzle 18 toward the boundary between the lower surface of the wafer W protruding from the polishing pad 20 and the polishing pad 20.

The amount by which the wafer W is projected from the periphery of the polishing pad 20 is set within a range in which the carrier 24 holding the wafer W does not tilt.

The operation of the wafer polishing apparatus 10 according to the present embodiment configured as described above is as follows.

First, the wafer W placed on a supply stage (not shown) is held by the wafer holding head 14 and transferred onto the polishing pad 20. At this time, the holding of the wafer W is performed as follows. First, the wafer holding head 14 is moved above the wafer W. Then, to abut the upper surface of the wafer W to the protective sheet 34. In this state, a suction pump (not shown) is driven to suck air from a suction / outlet 40 formed in the carrier 24. Thus, the wafer W is suction-held at the lower portion of the carrier 24 via the protection sheet 34. The transfer of the wafer W is performed by moving the wafer holding head 14 holding the wafer W in the horizontal and vertical directions by the head moving mechanism 16. The wafer W is transported to a position eccentric from the center of the polishing pad 20, as shown in FIG.

When the wafer W is transferred onto the polishing pad 20, the suction holding by the carrier 24 is released. That is, the driving of the suction pump is stopped, the vacuum is broken, and the wafer W is opened on the polishing pad 20.

Next, a pump (not shown) is driven to supply air to the carrier airbag 52 and the retainer ring airbag 64. As a result, the carrier airbag 52 and the retainer ring airbag 64 expand. At the same time, an air supply pump (not shown) is driven to supply air from a suction / blowing port 40 formed in the carrier 24. As a result, an air layer is formed between the protection sheet 34 and the lower surface of the carrier 24, and the protection sheet 34 is pressed against the air layer, whereby the wafer W is pressed against the polishing pad 20 with a predetermined pressure. Also,
The retainer ring 30 is pressed against the polishing pad 20 at a predetermined pressure. In this state, the polishing table 12 is rotated and the wafer holding head 14 is rotated. Then, a slurry is supplied from the slurry supply nozzle 21 onto the rotating polishing pad 20. Thereby, the wafer W is polished on the polishing pad 20.

When the wafer W is polished by a predetermined amount, the processing is completed. Thereafter, the wafer W is cleaned and recovered by supplying cleaning water onto the polishing pad 20, and the recovery of the wafer W is performed as follows.

First, as shown in FIG. 3A, the rotation of the wafer holding head 14 is stopped. Next, the pressing of the carrier 24 by the carrier airbag 52 is released. Next, an intake pump (not shown) is driven to suck air from a suction / blowing port 40 formed in the carrier 24, and the wafer W is transferred to the carrier 24 via the protection sheet 34.
Is held by suction.

Next, as shown in FIG. 3B, the horizontal moving mechanism is driven to move the wafer holding head 14 by a predetermined amount along the polishing pad 20. As a result, the wafer W
Project from the periphery of the polishing pad 20 by a predetermined amount.

Next, as shown in FIG. 3C, the liquid is sprayed from the wafer peeling spray nozzle 18 toward the boundary between the polishing pad 20 and the lower surface of the wafer W protruding from the peripheral edge of the polishing pad 20. Is done. The injected liquid is
The wafer W enters between the wafer W and the polishing pad 20 from the boundary portion, and the wafer W is forcibly levitated from the polishing pad 20. Thereby, the wafer W is separated from the polishing pad 20.

The ejection of the liquid is continuously performed for a predetermined time. After the ejection is completed, the wafer holding head 14 is raised and the wafer W is collected from the polishing pad 20 as shown in FIG. The collected wafer W is transferred to a collection stage (not shown) by the movement of the wafer holding head 14.

As described above, according to the wafer polishing apparatus 10 of the present embodiment, the wafer W after polishing is projected from the peripheral portion of the polishing pad 20, and the boundary between the projected wafer W and the polishing pad 20. By injecting the liquid toward the portion, the wafer W is lifted off the polishing pad 20 and separated, so that the wafer W can be easily collected from the polishing pad 20 without applying excessive force.

Further, since the liquid can be directly jetted to the boundary portion between the wafer W and the polishing pad 20, the wafer W can be efficiently separated from the polishing pad 20 in a short time.

Further, if the existing wafer transfer means is used, the wafer separation nozzle 18 is simply installed near the polishing platen 12, so that the apparatus can be easily constructed.

In this embodiment, the liquid is ejected to separate the wafer W from the polishing pad 20, but a gas such as air may be ejected.

The number of the wafer peeling nozzles 18 is not limited to one but may be plural, and liquid or gas may be jetted from plural places.

[0047]

As described above, according to the present invention,
The wafer W after polishing is protruded from the periphery of the polishing pad, and the liquid is jetted toward the boundary between the protruded wafer and the polishing pad, thereby easily polishing the wafer without applying excessive force. Can be recovered from the pad.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the overall structure of a wafer polishing apparatus.

FIG. 2 is a longitudinal sectional view showing a configuration of a wafer holding head.

FIG. 3 is an explanatory view of a method for collecting a wafer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Wafer grinding | polishing apparatus, 12 ... Polishing table, 14 ... Wafer holding head, 16 ... Head moving mechanism, 18 ... Wafer peeling nozzle, 20 ... Polishing pad, 22 ... Head main body, 24 ... Carrier, 26 ... Carrier drive mechanism , 28 ...
Carrier pressing mechanism, 30 ... retainer ring, 30A ...
Convex part, 32: retainer ring pressing mechanism, 34: protective sheet, 35: bearing unit, 36: motor, 38: air groove, 38A: outer peripheral groove, 38B: inner peripheral groove, 38C: intermediate groove, 40: suction / blowing Outlet, 42 ... air flow path, 44 ... drive shaft, 46 ... drive plate, 48 ... drive pin, 50 ... recess, 52 ... carrier airbag, 5
4: carrier pressing member, 56: retainer ring holder, 56A: concave portion, 56B: outer peripheral flange portion, 56C:
Inner peripheral flange, 58 ... bolt, 60 ... mounting ring, 6
0A: outer peripheral flange, 62: snap ring, 62A
... Groove, 64 ... Retainer ring airbag, 66 ... Retainer ring pressing member, 68 ... Vent hole, 70 ... Movement plate, 72 ... Guide rail, 74 ... Carriage, 7
6 ... ceiling frame, 78 ... guide rail, 80 ... angle

Claims (2)

[Claims] 1. A wafer polishing apparatus for pressing a wafer against a polishing pad by pressing the upper surface of the wafer with a carrier and polishing the wafer, and collecting the wafer from the polishing pad by suctioning the upper surface of the polished wafer with the carrier. In the wafer recovery method, the polished wafer is sucked by the carrier, and the wafer is slid along the polishing pad via the carrier, so that the wafer is projected from the periphery of the polishing pad by a predetermined amount, A wafer recovery method for a wafer polishing apparatus, comprising: ejecting a fluid between the protruded wafer and the polishing pad to separate the wafer from the polishing pad and recovering the wafer with the carrier. 2. A wafer polishing apparatus for pressing a wafer against a polishing pad by pressing an upper surface of the wafer with a carrier and polishing the wafer, and recovering the wafer from the polishing pad by suctioning the upper surface of the polished wafer with the carrier. Moving means for moving the wafer along the polishing pad by moving the carrier along the polishing pad; and a wafer protruding a predetermined amount from the periphery of the polishing pad and the polishing A fluid ejecting means for ejecting a fluid between the polishing pad and the pad, wherein the carrier is moved by the moving means so that the polished wafer projects from the periphery of the polishing pad by a predetermined amount, and the projected wafer By ejecting a fluid from the fluid ejecting means between and the polishing pad, Wafer collecting device wafer polishing apparatus, wherein a serial wafer is peeled from the polishing pad recovered in the carrier.