JP4583580B2 - Pad conditioner and conditioning method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pad conditioner for a polishing pad and a conditioning method.
[0002]
[Prior art]
The polishing apparatus polishes the surface of the wafer by pressing the wafer that is also horizontally rotated against the polishing pad that is adhered to the platen that is horizontally rotated and supplying slurry between the polishing pad and the wafer. .
However, it is known that when this polishing operation is repeated for a certain period of time, the polishing surface of the polishing pad is scrubbed and smoothed by the interaction with the wafer, and the polishing ability decreases.
[0003]
Therefore, in order to recover the polishing ability that has been reduced in this way, it is necessary to condition the polishing pad periodically or while performing the polishing operation of the wafer. Further, as a result of the polishing operation of the wafer, non-uniform wear occurs on the polishing pad, and it is also necessary to repair it uniformly.
[0004]
A conventional pad conditioner for a polishing pad allows a diamond mounted on the lower surface of the head to come into contact with the surface of the polishing pad while horizontally swinging a swing arm having a head that is rotated horizontally. The high part of the pad is ground and repaired, and the worn polishing pad is roughened back. In this case, in the conditioning work, it is necessary to wash away the wafer shavings and slurry that have entered the polishing pad, and the grinding pad grinding waste generated during the conditioning work. Thus, a cleaning liquid, for example, pure water is released to the surface of the polishing pad.
[0005]
The cleaning liquid supplied onto the polishing pad flows by the centrifugal force outward in the radial direction of the polishing pad, and removes the dust when discharged from the outer peripheral portion of the polishing pad to the outside. It was.
[0006]
[Problems to be solved by the invention]
However, dust that has entered the fibers of the polishing pad may remain on the polishing pad without being completely washed away only by the centrifugal force of the polishing pad. In general, a diamond disk used for a conditioning operation is configured by attaching diamond grains over the entire surface of a disk-shaped base metal by an electrodeposition method such as nickel electrodeposition or titanium electrodeposition. In a conditioning operation for sharpening the polishing surface and restoring the roughness, each diamond particle may receive a large external force from the polishing pad and fall off the base metal.
[0007]
In these cases, if the polishing operation of the wafer is performed with the diamond particles or dust remaining on the polishing pad, there is a problem that micro scratches are generated on the polishing surface of the wafer and the quality of the wafer is deteriorated.
[0008]
The present invention has been made in view of the above-described circumstances, and reduces the residual amount on the polishing pad such as dust on the polishing pad and diamond grains dropped from the diamond disk. An object of the present invention is to provide a pad conditioner and a conditioning method capable of suppressing the generated microscratches.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention comprises a head for attaching a diamond disk having diamond grains fixed to the surface thereof, and a rotational drive mechanism for rotating the head, and the head is in contact with the surface of the polishing pad. A pad conditioner for grinding a polishing pad by rotating a diamond disk, the cleaning liquid supply means for supplying a cleaning liquid to the head between the diamond disk and the polishing pad, the diamond disk and the polishing pad, The pad conditioner provided with the washing | cleaning liquid collection | recovery means which collect | recovers the washing | cleaning liquid passed between is proposed.
[0010]
In the pad conditioner, it is effective if the cleaning liquid supply means discharges the cleaning liquid from the center of the diamond disk, and the cleaning liquid recovery means recovers the cleaning liquid radially outward of the diamond disk. .
[0011]
In addition, the cleaning liquid supply means includes a cleaning liquid supply path disposed along the rotation center of the head, and a cleaning liquid supply port disposed at the center of the diamond disk and connected to the cleaning liquid supply path, The cleaning liquid recovery means includes a cleaning liquid recovery port formed in an opening in the radial direction of the diamond disk, and a cleaning liquid recovery path connected to the cleaning liquid recovery port and disposed along the rotation center of the head. It is good.
[0012]
In this case, it is effective if a plurality of the cleaning liquid recovery ports are provided at intervals in the circumferential direction of the diamond disk.
Further, a swivel joint that connects the cleaning liquid recovery port to the cleaning liquid recovery path may be provided.
[0013]
Further, according to the present invention, by rotating a head on which a diamond disk formed by fixing diamond grains on the surface is rotated, the diamond disk is rotated while being in contact with the surface of a polishing pad. A conditioning method is also proposed in which a cleaning liquid is supplied between the polishing pad and the polishing pad, and the cleaning liquid passed between the diamond disk and the polishing pad is recovered.
[0014]
[Action]
According to the pad conditioner according to the present invention, the polishing pad is conditioned by rotating the diamond disk to which the diamond grains are fixed on the surface of the polishing pad by the operation of the rotation driving mechanism. At this time, the cleaning liquid supply means operates to supply the cleaning liquid between the diamond disk and the polishing pad, and the dust on the polishing pad and the dust generated by the conditioning operation are washed away by the cleaning liquid.
[0015]
Further, since the cleaning liquid passed between the diamond disk and the polishing pad is recovered by the operation of the cleaning liquid recovery means, the diamond particles dropped from the diamond disk can be recovered together with the cleaning liquid together with the dust that has been washed away. It becomes possible. Since this cleaning liquid recovery means is provided on the head, the cleaning liquid and dust can be recovered immediately after passing between the diamond disk and the polishing pad, and it is ensured that the dust remains on the polishing pad. Can be prevented.
[0016]
In particular, the cleaning liquid supply means discharges the cleaning liquid from the center of the diamond disk, and the cleaning liquid recovery means recovers the cleaning liquid radially outward of the diamond disk, so that the cleaning liquid is sufficiently diffused between the diamond disk and the polishing pad. Dust can be washed away and recovered efficiently.
[0017]
Further, by arranging the cleaning liquid supply path and the cleaning liquid recovery path along the rotation center of the head, it is possible to arrange these supply / recovery paths in a fixed state regardless of the rotation of the head. In this case, if a plurality of cleaning liquid recovery ports are provided at intervals in the circumferential direction of the diamond disk, the cleaning water diffusing over the entire surface of the diamond disk can be reliably recovered from the cleaning liquid recovery port.
Further, the cleaning liquid recovery means can be configured more simply by connecting the cleaning liquid recovery port to the cleaning liquid recovery path via a swivel joint.
[0018]
Further, according to the conditioning method according to the present invention, both the supply of the cleaning liquid between the diamond disk and the polishing pad and the recovery of the cleaning liquid that has passed between the diamond disk and the polishing pad are performed in the head. The cleaning water containing dust is collected before flowing out from between the head and the polishing pad, and it is possible to reliably prevent the dust from remaining on the polishing pad.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a pad conditioner and a conditioning method according to the present invention will be described with reference to FIGS.
As schematically shown in FIG. 1, a pad conditioner 1 according to this embodiment includes a head 3 disposed on a polishing pad 2 that is horizontally rotated, a swing arm 4 that supports the head 3, A drive mechanism 5 that swings the swing arm 4 in the horizontal direction and rotates the head 3 horizontally, a cleaning liquid supply means 6 that supplies the cleaning liquid to the head 3, and a cleaning liquid recovery means 7 that recovers the cleaning liquid from the head 3. It has.
[0020]
As shown in FIG. 2, the head 3 has a diamond disk 9 formed by electrodepositing diamond grains 8 on the surface of a disk-shaped base metal, and the diamond grains 8 side down as shown in FIG. It is comprised so that it may mount on a lower surface toward. Therefore, the base of the diamond disk 9 is made of a magnetic material, and a magnet (not shown) for magnetically attaching the diamond disk 9 is provided on the lower surface of the head 3.
[0021]
As shown in FIG. 3, a center hole 10 that vertically penetrates the head 3 is provided in the center of the head 3, and a cleaning liquid recovery means 7, which will be described later, is formed on the lower surface near the periphery of the head 3. A plurality of cleaning liquid suction holes 11 constituting a part are provided at intervals in the circumferential direction. Further, the diamond disk 9 is provided with a through hole 12 communicating with the center hole 10 of the head 3 at the center thereof.
[0022]
In FIG. 1 and FIG. 3, the head 3 is shown as being configured integrally with the upper rotating shaft 13 for the purpose of simplifying the drawing for the sake of convenience of explanation. In addition, a mechanism for generating a pressing force against the polishing pad 2 by moving the head 3 up and down is provided. In the drawings, mechanical elements such as bearings are omitted to simplify the drawings.
[0023]
The drive mechanism 5 includes a swing drive mechanism 14 that swings the swing arm 4 and a rotation drive mechanism 15 that rotates the head 3 horizontally at the tip of the swing arm 4. The swing drive mechanism 14 includes a first speed reducer 17 fixed to the base 16 and a first motor 21 connected to an input shaft 18 of the speed reducer 17 via gears 19 and 20. Yes. The base end of the swing arm 4 is fixed to the output shaft 17a of the speed reducer 17, and the swing arm 4 swings over a preset angle range in a horizontal plane by the operation of the first motor 21. It is supposed to be made.
[0024]
The rotary drive mechanism 15 includes a hollow rotary shaft 13 fixed to the head 3, a hollow drive shaft 22 disposed through the center hole of the speed reducer 17, and the drive shaft 22 and the rotary shaft 13. The attached pulleys 23 and 24, the belt 25 spanned around the pulleys 23 and 24, the output gear 27 meshing with the gear 26 attached to the drive shaft 22, and the second reduction gear having the output gear 27. And a second motor 29 for inputting a rotational driving force to the speed reducer 28.
[0025]
The cleaning liquid supply means 6 includes a cleaning liquid supply pipe 31 arranged in a passage formed by using the rotary shaft 13 and the drive shaft 22 as a hollow shaft and through the cover 30 of the swing arm 4. ing. The cleaning liquid supply pipe 31 passes through the central hole 10 provided in the head 3 and opens into the through hole 12 of the diamond disk 9 attached to the lower surface of the head 3. The cleaning liquid is pure water, for example, and is supplied from a cleaning liquid supply source (not shown).
[0026]
Similar to the cleaning liquid supply pipe 31, the cleaning liquid recovery means 7 includes a first cleaning liquid recovery pipe 32 arranged from the hollow drive shaft 22 through the cover 30 of the arm 4, and the hollow rotary shaft 13. Through the rotation center of the head 3, the second cleaning liquid recovery pipe 33 arranged in a double tube shape outside the cleaning liquid supply pipe 31 is attached to the second cleaning liquid recovery pipe 33 and the head 3. And a swivel joint 34 that delivers the cleaning liquid sucked from the cleaning liquid suction hole 11 of the head 3 to the second cleaning liquid recovery pipe 33. The tip of the first cleaning liquid recovery pipe 32 is connected to a suction pump (not shown).
[0027]
The operation of the pad conditioner 1 according to this embodiment configured as described above will be described below.
First, by operating the second motor 29, the second motor 29 is disposed at the tip of the swing arm 4 via the speed reducer 28, the gears 27 and 26, the drive shaft 22, the pulleys 23 and 24, the belt 25, and the rotary shaft 13. The head 3 is turned horizontally. Further, by operating the first motor 21, the swing arm 4 is swung in the horizontal direction over a preset angle range via the gears 19 and 20 and the speed reducer 17.
[0028]
In this state, the surface of the polishing pad 2 is ground and conditioned by bringing the diamond grains 8 of the diamond disk 9 attached to the lower surface of the head 3 into contact with the polishing pad 2 rotating horizontally.
At this time, the cleaning liquid supply means 6 is operated to supply pure water from the cleaning liquid supply source to the head 3 via the cleaning liquid supply pipe 31, and as indicated by an arrow A in FIG. Further, pure water is supplied between the polishing pad 2 and the diamond disk 9 through the through hole 12 of the diamond disk 9. At the same time, the cleaning liquid recovery means 7 is activated.
[0029]
In this case, the pure water supplied from the through hole 12 of the diamond disk 9 flows outward in the radial direction of the diamond disk 9 due to the rotational movement of the polishing pad 2 and the rotation of the diamond disk 9. The slurry adhering to the polishing pad 2, the shavings of the wafer, or the diamond particles that have fallen off from the diamond disk 9 are washed away.
[0030]
The head 3 is provided with a plurality of cleaning liquid suction holes 11 disposed radially outward of the diamond disk 9. The cleaning liquid suction holes 11 have a swivel joint 34, a second cleaning liquid recovery pipe 33, Since the suction pump is connected via the single cleaning liquid recovery pipe 32, the pure water flowing in the radial direction from the center of the diamond disk 9 and flowing outward in the radial direction of the diamond disk 9 is the cleaning liquid for the head 3. It is sucked from the suction hole 11 and collected.
[0031]
In this case, since a plurality of cleaning liquid suction holes 11 are provided in the vicinity of the periphery of the head 3 at intervals in the circumferential direction, the pure water flowing between the polishing pad 2 and the diamond disk 9 is shown in FIG. As indicated by the arrow B, the liquid is sucked into the head 3 from any of the cleaning liquid suction holes 11. That is, since the pure water supplied between the polishing pad 2 and the diamond disk 9 does not leak outward in the radial direction of the head 3, substantially all of the pure water is recovered from the cleaning liquid suction hole 11. The slurry, wafer shavings, etc. remaining in 2 can be recovered, and the diamond particles 8 that have fallen off from the diamond disk during the conditioning operation can also be recovered without remaining on the polishing pad 2.
[0032]
Further, the conditioning method according to the present embodiment uses the pad conditioner 1 described above to supply a cleaning liquid between the diamond disk 9 and the polishing pad 2 in the head 3, and the diamond disk 9 and the polishing pad. Since the polishing pad 2 is ground by the diamond disk 9 while collecting the cleaning liquid that has passed between the two, the dust that has been washed away can be quickly collected. That is, since the cleaning liquid supplied onto the polishing pad 2 is recovered before diffusing to the entire polishing pad 2, dust can be recovered more effectively.
[0033]
As described above, according to the pad conditioner 1 and the conditioning method according to the present embodiment, unlike the conventional pad conditioner that causes the cleaning liquid containing dust to flow out of the polishing pad 2 by the centrifugal force of the polishing pad 2, Since the cleaning liquid is forcibly recovered from the cleaning liquid suction hole 11 of the head 3, dust remaining on the polishing pad 2 after the conditioning operation is completed can be reduced. In the polishing operation performed thereafter, the micro scratches on the wafer surface can be reduced. There is an effect that generation can be greatly reduced.
[0034]
In the above embodiment, the rotation drive mechanism 5 having the pulleys 23, 24 and the belt 25 has been described as an example. However, the rotation drive mechanism 5 is not limited to this, and any equivalent drive mechanism is employed. Needless to say. Further, although pure water is used as the cleaning liquid, other arbitrary cleaning liquid may be used instead.
[0035]
【The invention's effect】
As described above, according to the pad conditioner and the conditioning method according to the present invention, when the diamond disk to which the diamond grains are attached is attached to the head and brought into contact with the polishing pad while rotating, the diamond disk and the polishing pad Since the cleaning liquid is supplied during the period and the cleaning liquid circulated between the diamond disk and the polishing pad is recovered by the head, dust generated in the conditioning operation can be reliably recovered together with the cleaning liquid. As a result, there is an effect that the amount of dust remaining on the polishing pad can be greatly reduced, and the occurrence of micro scratches on the surface of the wafer in subsequent polishing operations can be suppressed.
[0036]
In addition, if the cleaning liquid is discharged from the center of the diamond disk and the cleaning liquid is recovered outward in the radial direction of the diamond disk, dust generated in the conditioning operation can be recovered most efficiently and quickly. There is an effect.
[0037]
Furthermore, by arranging the cleaning liquid supply path and the cleaning liquid recovery path along the rotation center of the head, the cleaning liquid supply path and the cleaning liquid recovery path can be configured as a fixed structure member separately from the rotated head. There is an effect that can be simplified.
[0038]
In addition, by providing a plurality of cleaning liquid recovery ports spaced apart in the circumferential direction of the diamond disk, the cleaning liquid after cleaning can be recovered from any cleaning liquid recovery port even if the head rotates. It is possible to reliably remove dust from.
Furthermore, if the swivel joint is provided to connect the cleaning liquid recovery port to the cleaning liquid recovery path, the rotating cleaning liquid recovery port and the cleaning liquid recovery path as a fixed structure member are connected to smoothly recover the cleaning liquid after cleaning. There is an effect that can be done.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing an embodiment of a pad conditioner according to the present invention.
2 is a view showing a lower surface of the head of the pad conditioner of FIG. 1. FIG.
3 is an enlarged cross-sectional view showing in detail a head portion of the pad conditioner of FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pad conditioner 2 Polishing pad 3 Head 6 Cleaning liquid supply means 7 Cleaning liquid collection means 8 Diamond grain 9 Diamond disk 11 Cleaning liquid suction hole (cleaning liquid collection port)
12 Through hole (cleaning liquid supply port)
15 Rotation drive mechanism 31 Cleaning liquid supply pipe (cleaning liquid supply path)
32, 33 Cleaning liquid recovery pipe (cleaning liquid recovery path)
34 Swivel joint

Claims (6)

A head for attaching a diamond disk having diamond grains fixed to the surface and a rotation drive mechanism for rotating the head, and grinding the polishing pad by rotating the diamond disk in contact with the surface of the polishing pad. A pad conditioner that performs
The head is provided with a cleaning liquid supply means for supplying a cleaning liquid between the diamond disk and the polishing pad, and a cleaning liquid recovery means for recovering the cleaning liquid passed between the diamond disk and the polishing pad. Pad conditioner characterized by that. The pad conditioner according to claim 1, wherein the cleaning liquid supply means discharges the cleaning liquid from the center of the diamond disk, and the cleaning liquid recovery means recovers the cleaning liquid radially outward of the diamond disk. . The cleaning liquid supply means includes a cleaning liquid supply path disposed along the center of rotation of the head, and a cleaning liquid supply port disposed at the center of the diamond disk and connected to the cleaning liquid supply path.
The cleaning liquid recovery means includes a cleaning liquid recovery port having an opening formed radially outward of the diamond disk, and a cleaning liquid recovery path connected to the cleaning liquid recovery port and disposed along the rotation center of the head. The pad conditioner according to claim 1, wherein the pad conditioner is provided. The pad conditioner according to claim 3, wherein a plurality of the cleaning liquid recovery ports are provided at intervals in the circumferential direction of the diamond disk. The pad conditioner according to claim 3 or 4, further comprising a swivel joint for connecting the cleaning liquid recovery port to the cleaning liquid recovery path. By rotating a head on which a diamond disk formed by fixing diamond grains on the surface is rotated, the diamond disk is rotated while being in contact with the surface of the polishing pad. A conditioning method comprising: supplying a cleaning solution to the substrate and collecting the cleaning solution passed between the diamond disk and the polishing pad.

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