Pad Conditioner Cleaning System

Abstract

To provide a method for washing a conditioner head.SOLUTION: A pad conditioner head washing tool has: a first clamp which is configured so as to cause a first portion of a sponge to removably engage with an external surface of a disc-shaped pad conditioner head at a first position; a second clamp which is configured so as to cause a second portion of the sponge to removably engage with the external surface of the disc-shaped pad conditioner head at a second position; and an arm for coupling the first clamp to the second clamp. The arm has flexibility sufficient for separating the first clamp and the second clamp and fitting the same around the disc-shaped pad conditioner head, and has a tensile force sufficient for energizing the first clamp and the second clamp to an inner side and pressing the sponge against the external surface of the pad conditioner head.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates to chemical mechanical polishing, and more particularly to cleaning pad conditioners. [Background technology]

[0002] Integrated circuits are typically formed on substrates by sequentially depositing conductive, semiconductive, or insulating layers on a silicon wafer. One fabrication step involves depositing a filler layer over a non-planar surface and planarizing the filler layer. In some applications, the conductive filler layer is planarized until the top surface of the patterned layer is exposed. In other applications, such as oxide polishing, the filler layer is planarized until a predetermined thickness remains over the non-planar surface. Additionally, planarization of the substrate surface is typically required for photolithography.

[0003] Chemical-mechanical polishing (CMP) is one accepted planarization method. This planarization method typically requires mounting a substrate on a carrier or polishing head. The exposed surface of the substrate is typically placed against a rotating polishing pad. The carrier head applies a controllable load to the substrate, pressing it against the polishing pad. A polishing fluid is typically supplied to the surface of the polishing pad.

[0004] The polishing system typically includes a conditioner system having a conditioner head holding a conditioner disk with an abrasive lower surface for conditioning the polishing pad, which maintains a consistent roughness on the polishing surface to ensure uniform polishing conditions from wafer to wafer. Summary of the Invention

[0005] In one aspect, a pad conditioner head cleaning tool includes a first clamp, a second clamp, and an arm coupling. The first clamp is configured to releasably engage a first portion of a sponge at a first position relative to an outer surface of the disc-shaped pad conditioner head. The second clamp is configured to releasably engage a second portion of the sponge at a second position relative to the outer surface of the disc-shaped pad conditioner head. The arm couples the first clamp to the second clamp. The arm is flexible enough to allow the first clamp and the second clamp to separate and fit around the disc-shaped pad conditioner head, and has sufficient tension to urge the first clamp and the second clamp inward, pressing the sponge against the outer surface of the pad conditioner head.

[0006] Implementations may include one or more of the following features.

[0007] The first clamp and the second clamp may be arcuate. The arm may be arcuate. The center of the arc of the arcuate first clamp and the second clamp may be at the center of the pad conditioner head when the pad conditioner head cleaning tool is secured to the pad conditioner head. The first clamp may be a unitary piece, and the second clamp may be a unitary piece. The first clamp and the second clamp may each have an upper flange and a lower flange configured to accommodate the conditioner head. Portions of the outer surfaces of each of the first clamp and the second clamp may be recessed. The first clamp, the second clamp, and the arm may be a unitary arcuate body with a gap between the first clamp and the second clamp. The gap is configured to receive a sponge.

[0008] The tool may include a sponge. The sponge may be a dry sponge. The sponge may be a wet sponge. The sponge may be disc-shaped.

[0009] In another aspect, a method for cleaning a pad conditioner head includes moving two clamp arms of a cleaning tool inward toward the disk-shaped pad conditioner head to press a sponge against an outer surface of the disk-shaped pad conditioner head, and causing relative motion between the cleaning tool and the pad conditioner head to wipe the pad conditioner head with the sponge.

[0010] Embodiments may include, but are not limited to, one or more of the following advantages: Polishing quality may be improved, for example, with fewer scratches and defects caused by dried abrasive particles from polishing slurry buildup that detaches from the pad conditioner during the polishing process. Furthermore, the amount of wafers discarded due to defects may be reduced. Maintenance downtime of the polishing system may be significantly reduced, thereby increasing polishing system productivity and reducing operator time by reducing the time devoted to the pad conditioner cleaning process. Switching between different cleaning modes (i.e., dry cleaning and wet cleaning) is easier. The cleaning process can be quickly changed by adjusting the tool's pressure engagement with the pad conditioner. Furthermore, the cleaning process can be quickly changed by changing sponge type and / or adding cleaning fluid.

[0011] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims. [Brief explanation of the drawings]

[0012] [Figure 1A]1 is a schematic cross-sectional view of a pad conditioner system with a conditioner head engaging a polishing pad of a chemical mechanical polishing system. [Figure 1B] 1B is a schematic cross-sectional view of the pad conditioner cleaning system of the chemical mechanical polishing system of FIG. 1A, with the pad conditioner head in a cleaning position. [Figure 2] FIG. 1C is a schematic cross-sectional view of the pad conditioner cleaning system of FIG. 1B. [Figure 3] FIG. 1C is a front perspective view of the pad conditioner cleaning system of FIG. 1B. [Figure 4] 2 is a front perspective view of a pad conditioner cleaning system installed on a pad conditioner system, the pad conditioner system being separated from the chemical mechanical polishing system of FIG. 1; [Figure 5A] FIG. 1C is a front view of the first sponge of FIG. 1B. [Figure 5B] FIG. 1C is a front view of the second sponge of FIG. 1B. [Figure 6] 10A-10C illustrate a method for cleaning the pad conditioner. DETAILED DESCRIPTION OF THE INVENTION

[0013] Like reference numbers and designations in the various drawings refer to like elements.

[0014] During chemical mechanical polishing, a polishing liquid, such as an abrasive polishing slurry, is supplied to the surface of the polishing pad. The polishing system typically includes a conditioner system having a conditioner head and a conditioner disk having an abrasive underside for conditioning the polishing pad.

[0015] Rotating the platen and polishing pad can cause centrifugal migration of polishing fluid from the polishing pad. Some of the polishing fluid can flow off the polishing pad and collect in a basin, while some of the polishing fluid can splash off and adhere to the conditioner head. When this happens, the polishing fluid can form larger particles on the conditioner head, for example, by agglomeration or simply by drying. The accumulation of dried or agglomerated polishing fluid on the polishing pad over time can have many detrimental effects. For example, these larger particles can shed and return to the polishing surface, thereby creating a risk of scratch formation and defects. A significant amount of non-productive time is required to clean the conditioner head and conditioner disk to prevent the accumulation of dried polishing fluid.

[0016] A conditioner head cleaning tool that can be easily attached to the conditioner head and does not require equipment disassembly can mitigate these deleterious effects.

[0017] 1A illustrates a polishing system 20 operable to polish a substrate 10. The polishing system 20 includes a rotatable platen 24 on which a polishing pad 30 is positioned. The polishing system 20 may further include a platen shield 26 surrounding the rotatable platen 24 and separated from the rotatable platen 24 by an annular gap 22. The rotatable platen 24 is operable to rotate about an axis 28. For example, a motor 30 may rotate a drive shaft 32 to rotate the rotatable platen 24.

[0018] The polishing system 20 includes a carrier head 70 operable to hold the substrate 10 against the polishing pad 30. The carrier head 70 is suspended from a support structure 72, e.g., a carousel or track, and is connected to a carrier head rotation motor 76 by a carrier drive shaft 74 such that the carrier head can rotate about an axis 71. Furthermore, the carrier head 70 can reciprocate laterally across the polishing pad 30, for example, by moving within radial slots in the carousel 72 when driven by an actuator, by rotating the carousel when driven by a motor, or by moving back and forth along the track when driven by an actuator. In operation, the platen 24 rotates about its central axis 25, and the carrier head 70 rotates about its central axis 71 and translates laterally across the top surface of the polishing pad 30.

[0019] The polishing system 20 can include a polishing fluid delivery arm 34. During polishing, the arm 34 is operable to dispense a polishing fluid 36. The polishing fluid 36 can be a slurry containing abrasive particles. The polishing fluid 36 can be referred to by many names, such as an abrasive polishing slurry, an abrasive polishing fluid, or a polishing slurry.

[0020] The polishing system 20 may further include a conditioner system 40 having a rotatable conditioner head 42, which may include an abrasive undersurface, for example, on a removable conditioning disk, for conditioning the polishing surface 38 of the primary polishing pad 30. The conditioner system 40 may further include a motor 44 for driving the conditioner head 42 and a drive shaft 46 connecting the motor 44 to the conditioner head 42. The conditioner system 40 may further include an actuator configured to move the conditioner head 40 in a lateral sweeping motion across the polishing pad 30. The conditioner system 40 may further include an arm 88 for rotating the pad conditioner head 42 and moving the pad conditioner head 42 laterally onto and off the polishing pad 30. A notch or cutout 22 may be formed in the platen shield 26 to allow the conditioner head 40 to move laterally out of the way of the polishing pad 30 as shown in FIG.

[0021] Some of the polishing fluid 36 may run off the polishing pad 30 and collect below the polishing system 20, while some of the polishing fluid 36 on the polishing pad 30 may stick to the conditioner head 42. Additionally, conditioning the polishing pad 30 may remove polishing debris from the polishing pad 30, which may also stick to the conditioner head 42. In either case, the polishing fluid 36 on the carrier head 70 may dry and further accumulate on the conditioning pad head 42.

[0022] 1B shows conditioner pad head cleaning tool 50 installed on conditioner head 42 of polishing system 20. Conditioner pad head cleaning tool 50 includes sponge holder 52 and sponge 54. As shown in FIG. 2, sponge holder 52 urges sponge 54 against one or more surfaces of pad conditioner head 42, such as top surface 48 a or side surface 48 b, to clean pad conditioner head 42.

[0023] 5A and 5B, the sponge 54 may be disk-shaped. The sponge 54 may have an opening 90 extending through the body of the sponge, located at the center 96 of the sponge. The opening 90 is sized to accommodate the diameter of the drive shaft 46 connecting the motor 44 to the conditioner head 42. A slot 92 extends from the periphery 94 of the sponge 54 to this void. The slot 92 allows the sponge 54 to be placed around the periphery of the pad conditioner head 42.

[0024] The sponge 54 is made of a soft, porous, and absorbent material. The sponge 54 can be made of natural or synthetic materials. For example, the sponge 54 can be made from natural materials such as plant cellulose, animal sponge, hemp, or wood fibers. Alternatively, the sponge 54 can be made from synthetic materials such as polyester or polyurethane.

[0025] The sponge 54 can be a dry sponge or a wet sponge. A dry sponge does not have any fluid chemicals added to it. A dry sponge can be used for scraping. Referring to FIG. 5A, a dry sponge can have a waffle-like surface texture to enhance scrubbing. A wet sponge has a fluid added to it. As shown in FIG. 5B, a wet sponge can be used to scrape off dry scrubbing fluid 36 buildup, to soften and loosen dry scrubbing fluid 36 buildup, or to apply chemicals to the pad conditioning head 42. For example, deionized water, isopropyl alcohol, or potassium hydroxide can be applied to the sponge.

[0026] 2-4, sponge holder 52 includes two clamps 56a and 56b. Each clamp 56 has an upper jaw 58 and a lower jaw 60. A frame 62 connects upper jaw 58 and lower jaw 60. First clamp 56a has upper jaw 58a and lower jaw 60a connected by frame 62a, configured to engage a first portion 64 of sponge 54 relative to conditioner head 42. Second clamp 56b has upper jaw 58b and lower jaw 60b connected by frame 62b, configured to engage a second portion 66 of sponge 54 relative to conditioner head 42. Upper jaw 56 and lower jaw 58 are connected to move, e.g., expand, so as to be attached to conditioner head 42.

[0027] The two clamps 56a and 56b are arcuate, i.e., arc-shaped when viewed from above. The outer surfaces of the upper jaw 58 and the lower jaw 60 may have an indentation 78 formed in the top surface 80. The first clamp 56a has an upper surface 80 with an indentation 78a. The second clamp 56b has an upper surface 80 with an indentation 78b. The indentations 78a and 78b are configured to enhance an operator's grip on the clamps 56a and 56b. The bottom surfaces 82 of the clamps 56a and 56b may also have an indentation 78.

[0028] The inner surfaces of the upper and lower jaws 58, 60 may be flat, for example, as shown in FIG. 2, or may be convex, for example, as shown in FIG.

[0029] Clamps 56a and 56b are connected by an arm coupling 68, as shown in FIG. 3. The coupling arm may be an arc. Arm coupling 68 has sufficient flexibility to allow first clamp 56a and second clamp 56b to spread apart and fit around pad conditioner head 42 and sufficient tension to urge first clamp 56a and second clamp 56b inward to engage outer surface 48 of pad conditioner head 42. When the sponge is spread along outer surface 48, first clamp 56a and second clamp 56b can press sponge 54 inward against outer surface 48 of conditioner head 42. First clamp 56 and second clamp 56b are positioned by arm coupling 68 so that the centers of arc of first clamp and second clamp are centered at the center of conditioner head 42 when pad conditioner head cleaning tool 50 is secured to pad conditioner head 42. First clamp 56b, second clamp 56b and arm coupling 68 may be a single piece. Each clamp has upper and lower flanges configured to receive the conditioner head.

[0030] The sponge 54 is held by the sponge holder 52 in a manner such that the outer surface 84 of the sponge 54 is pressed against at least one surface 48 of the pad conditioner head 42. In operation, for example, an operator can rotate the sponge holder 52 and sponge 54 about an axis 86 while the pad conditioner head 42 remains stationary. In some embodiments, the sponge holder 52 and sponge 54 are rotated alternately in a clockwise and counterclockwise direction. Alternatively, the pad conditioner head 42 can be rotated about the axis 86 by, for example, rotating a drive shaft while the operator holds the sponge holder 52 and sponge 54 stationary. In either case, the sponge holder 52 holds the sponge 54 in contact with the pad conditioner head 42, and this relative motion wipes or scrapes off any buildup of abrasive fluid 36.

[0031] The sponge holder may be made of a resilient plastic. For example, the sponge holder may be made of steel, aluminum, high density polyethylene or a composite material.

[0032] FIG. 6 illustrates a method 600 for cleaning a pad conditioner head with a pad conditioner head cleaning tool. At 602, a sponge is placed in a gap in the pad conditioner head cleaning tool. Alternatively, the sponge can be placed directly on the pad conditioner head. At 604, a cleaning tool is placed on the conditioner head. Placing the pad conditioner head cleaning tool can include spreading a first clamp and a second clamp, moving the cleaning tool to encircle the conditioner head (and sponge), and releasing the first clamp to hold the sponge against the conditioner head. The sponge can be brought into further contact with the pad conditioner head, for example, by pressure applied by an operator to the outside of the clamps. At 606, the sponge is scrubbed against the pad conditioner head. The sponge is in contact with the pad conditioner head. Scrubbing the pad conditioner head can include rotating the pad conditioner head and / or rotating the pad conditioner head tool. In some embodiments, the scrubbing includes alternating directions in a clockwise-counterclockwise motion. The pad conditioner head may be scrubbed with a dry sponge. The damp sponge may be dampened with a cleaning solution. The damp sponge may then be scrubbed with the pad conditioner head. At 608, the pad conditioner head cleaning tool is removed from the pad conditioner head.

[0033] Although several embodiments have been described, it will be understood that various modifications may be made and, accordingly, other embodiments are within the scope of the following claims.

Claims

1. 1. A method for cleaning a conditioner head, comprising: moving two clamps of a cleaning tool connected by an arm coupling inward toward a disc-shaped pad conditioner head to press a sponge against an outer surface of the disc-shaped pad conditioner head, the arm coupling having sufficient flexibility to allow the clamps to spread and fit around the pad conditioner head and sufficient tension to urge the clamps inward to engage the outer surface of the pad conditioner head; Furthermore, the method comprises: causing relative motion between the cleaning tool and the pad conditioner head to wipe the pad conditioner head with the sponge; A method comprising:

2. The method of claim 1 , wherein causing relative motion includes rotating the pad conditioner head.

3. The method of claim 2 , wherein the sponge is wiped against the pad conditioner head while the pad conditioner head is attached to a drive shaft of a conditioner system of a chemical mechanical polishing system.

4. The method of claim 3 , wherein rotating the pad conditioner head includes a controller causing a motor to rotate the drive shaft.

5. The method of claim 2, wherein causing relative motion includes rotating the pad conditioner head tool in alternating clockwise-counterclockwise motion.

6. The method of claim 1 , wherein the sponge is a dry sponge.

7. wetting the sponge with a cleaning solution to provide a damp sponge; and wiping the pad conditioner head with the damp sponge; The method of claim 1 further comprising:

8. The method of claim 1 , wherein the two clamps are arcuate.

9. The method of claim 1 , wherein the two clamps of the cleaning tool are connected by a linking arm.

10. The method of claim 9 , wherein the two clamps and the connecting arm are one piece.

11. 10. The method of claim 9, including spreading the two clamps to fit around the disk-shaped pad conditioner head.

12. The method of claim 1 , wherein each of the two clamps includes an upper jaw and a lower jaw separated by a gap, and the method includes inserting the sponge into the gap between the upper and lower jaws.

Images