Cleaning system of polishing liquid supply arm

Abstract

To provide a polishing assembly.SOLUTION: A polishing assembly includes: a rotatable platen for supporting a polishing pad; a polishing liquid supply arm having an enclosure with an open bottom part, and one or a plurality of ports for supplying polishing liquid and cleaning fluid downward onto the polishing pad through an internal space of the enclosure; and a supply arm cleaning tool which is removably attached to the polishing liquid supply arm, where the cleaning tool extends below the supply arm, and the cleaning tool has a supply arm opposing surface having a shape for guiding cleaning fluid from the polishing liquid supply arm to the surface of the enclosure of the polishing liquid supply arm.SELECTED DRAWING: Figure 1B

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates to chemical mechanical polishing, and more particularly to cleaning of a polishing fluid delivery arm that delivers polishing fluid onto a polishing pad. [Background technology]

[0002] Integrated circuits are typically formed on substrates by sequentially depositing conductive, semiconductive or insulating layers on a silicon wafer. One manufacturing step during the manufacture of integrated circuits is polishing the fill layer to expose the top surface of the insulating layer below, for example to form vias, plugs and lines that provide conductive paths between thin film circuits on the substrate. In other applications, such as oxide polishing, the fill layer is planarized until a predetermined thickness remains above a non-planar surface. In addition, planarization of the substrate surface is also commonly required in photolithography.

[0003] Chemical mechanical polishing (CMP) is one accepted planarization method. This planarization method typically involves 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 exerts a controllable load on the substrate to press it against the polishing pad. A polishing fluid is typically delivered to the surface of the polishing pad by a polishing fluid delivery arm. The polishing fluid delivery arm may also have a nozzle for spraying a rinsing fluid onto the polishing pad to remove slurry or debris from the polishing surface. Summary of the Invention

[0004] In one aspect, a polishing assembly includes a rotatable platen for supporting a polishing pad, an open-bottom enclosure, a polishing fluid delivery arm having one or more ports for delivering polishing fluid and cleaning fluid downwardly onto the polishing pad through an interior space of the enclosure, and a delivery arm cleaning tool removably attached to the polishing fluid delivery arm, the cleaning tool extending below the delivery arm and having a delivery arm-facing surface shaped such that the cleaning tool delivers cleaning fluid from the polishing fluid delivery arm to a surface of the enclosure of the polishing fluid delivery arm.

[0005] In another aspect, a polishing liquid supply arm cleaning tool has a supply arm cleaning tool including an arm facing surface shaped to direct cleaning fluid ejected downward from the polishing liquid supply arm back onto an inner surface of an enclosure of the polishing liquid supply arm, and a retention tab configured to secure the supply arm cleaning tool to the polishing liquid supply arm.

[0006] In another aspect, a polishing fluid delivery arm cleaning tool includes a body configured to be removably secured to a polishing fluid delivery arm of a chemical mechanical polishing system, and an insert removably secured to the body, the insert having an arm-facing surface configured to direct cleaning fluid from the polishing fluid delivery arm back onto an inner surface of an enclosure of the polishing fluid delivery arm.

[0007] In another aspect, a method for cleaning a polishing liquid supply arm includes positioning a polishing liquid supply arm cleaning tool to extend below an enclosure of the polishing liquid supply arm, flowing a cleaning fluid through the polishing liquid supply arm, and directing the cleaning fluid from the polishing liquid supply arm back from a surface of the cleaning tool to a surface of the enclosure of the polishing liquid supply arm.

[0008] Optionally, embodiments may include one or more of the following advantages, but are not limited to: The quality of polishing may be improved, for example, with fewer scratches and defects caused by dried abrasive particles from the polishing slurry buildup that breaks off from the polishing fluid supply arm during the polishing process. Additionally, the amount of substrates that are discarded due to defects may be reduced. The downtime of the polishing system due to maintenance may be significantly reduced. The quality of the cleaning process may be improved, making it easier to clean difficult to access locations of the polishing fluid supply arm, which increases the productivity of the polishing system and reduces operator time by reducing the time devoted to the polishing fluid supply arm cleaning process. The cleaning process may be quickly changed by adjusting the cleaning fluid pressure or cleaning fluid composition.

[0009] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will become apparent from the description and drawings, and from the claims. [Brief description of the drawings]

[0010] [Figure 1A] 1 is a schematic cross-sectional view of a chemical mechanical polishing system. [Figure 1B] 2 is a schematic cross-sectional view of a polishing liquid supply arm cleaning tool installed on the polishing liquid supply arm of the chemical mechanical polishing system of FIG. 1. [Diagram 2] FIG. 2 is a perspective view of a polishing fluid supply arm cleaning tool mounted on the polishing fluid supply arm of a chemical mechanical polishing system. [Figure 3A] 2 is a cross-sectional view of the polishing fluid supply arm of the chemical mechanical polishing system of FIG. 1. [Figure 3B] FIG. 3 is a perspective view of the polishing fluid application arm cleaning tool of FIG. 2. [Figure 3C] FIG. 2 is a cross-sectional view of a polishing liquid supply arm cleaning tool fixed to the polishing liquid supply arm. [Figure 4] 3 is a rear perspective view of the polishing fluid application arm cleaning tool of FIG. 2 with a pocket. [Diagram 5] FIG. 3 is a cross-sectional view of the polishing liquid supply arm cleaning tool of FIG. 2. [Figure 6A] FIG. 2 is a perspective view of another embodiment of a polishing fluid delivery arm cleaning tool mounted on the polishing fluid delivery arm of a chemical mechanical polishing system. [Figure 6B] FIG. 6B is a cross-sectional view of the polishing liquid application arm cleaning tool of FIG. 6A. [Figure 7A] 13 is a cross-sectional perspective view of the bottom of another embodiment of an abrasive fluid application arm cleaning tool. FIG. [Figure 7B] FIG. 7B is a cross-sectional view of the polishing liquid application arm cleaning tool of FIG. 7A. [Figure 8] 11A to 11C are diagrams showing a method for cleaning the polishing liquid supply arm. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Like reference numbers and designations in the various drawings refer to like elements.

[0012] During chemical mechanical polishing, a polishing fluid, e.g., an abrasive polishing slurry, is applied to the surface of the polishing pad by a polishing fluid delivery arm. For example, the polishing fluid delivery arm may have a nozzle that dispenses the polishing fluid onto the surface of the polishing pad. When the polishing fluid impacts the polishing pad, some of the polishing fluid may redirect upward and form droplets suspended in the air. These droplets may accumulate on the polishing fluid delivery arm. Additionally, the polishing fluid may be splashed off the polishing pad by other components, e.g., a carrier head or a conditioner head.

[0013] Some of the polishing fluid may run off the feed arm where they may collect in a basin, but some of the polishing fluid may dry and accumulate on the feed arm. The accumulation of dried polishing fluid on the feed arm over time has many detrimental effects. For example, abrasive particles in the polishing fluid may form agglomerates. The agglomerates may subsequently fall off the feed arm and deposit on the polishing surface, thus creating a risk of scratch formation and defects. A significant amount of non-productive time and operator effort is required to clean the polishing fluid feed arm and prevent the accumulation of dried polishing fluid.

[0014] A polishing fluid dispensing arm cleaning tool that can be easily attached to the polishing fluid dispensing arm and does not require equipment disassembly can mitigate these deleterious effects.

[0015] 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 25 is positioned, and a platen shield 26 that surrounds the rotatable platen 24. The rotatable platen 24 is operable to rotate about an axis 28. For example, a motor 29 can rotate a drive shaft 22 to rotate the rotatable platen 24.

[0016] The polishing system 20 includes a carrier head 70 operable to hold the substrate 10 against the polishing pad 25. 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. In addition, the carrier head 70 can reciprocate laterally across the polishing pad 25, e.g., by moving within a radial slot in the carousel 72 when driven by an actuator, or by the carousel rotating 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 28, and the carrier head rotates about its central axis 71 and translates laterally across the upper surface of the polishing pad 25.

[0017] As shown in FIG. 1, the polishing system 20 further includes a polishing fluid supply system 30. The polishing fluid supply system 30 includes a polishing fluid supply arm 34 supported above the platen 24 by a base 32. A port 38, which may be located at an end of the arm 34, is coupled to a polishing fluid source 78, e.g., a reservoir, by a fluid line 68, e.g., a tube, a pipe, a passage in a solid, or the like. The port 38 may be a nozzle. During polishing, the supply arm 34 is operable to dispense polishing fluid 36 from the port 38. The flow rate of the polishing fluid 36 through the fluid line 68 may be controlled by a liquid flow controller (LFC), which may be controlled by a machine controller, e.g., a computer.

[0018] The polishing system 20 further includes one or more second ports 82, which may be located at the end or along the arm 34. The second ports 82 are coupled to a cleaning fluid source 86, e.g., a reservoir, by a fluid conduit 84, e.g., a tube, a pipe, a passage in a solid, or the like. During cleaning, the supply arm 34 is operable to dispense a cleaning fluid 88 from the port 82. The second port 82 may be a nozzle, which may spray the cleaning fluid onto the polishing pad 25. The cleaning fluid may be water, deionized water, or an isopropyl alcohol solution. The flow rate of the cleaning fluid 88 through the fluid conduit 78 may be controlled by a liquid flow controller (LFC), which may be controlled by a machine controller, e.g., a computer.

[0019] 3A , the polishing fluid supply arm 34 can form an enclosure 26 with an open bottom 40. Specifically, the polishing fluid supply arm 34 includes a roof 44 and a sidewall 46 extending downwardly from the roof 44. An interior space 42 is present between a ceiling 80 provided by the bottom of the roof 44 and an inner surface 58 of the sidewall 46.

[0020] During a cleaning operation, the cleaning fluid liquid 36 flows downwardly through the interior space 42 of the enclosure 26 onto the polishing pad 25. The enclosure 26 may help to suppress splashing of the cleaning fluid from the port 82 and / or the polishing pad 25.

[0021] In other embodiments, a port in the polishing fluid supply arm 34 can switch between supplying the polishing fluid 36 and supplying the cleaning fluid 82. In other embodiments, the polishing fluid supply arm 34 can have a single nozzle, such as a nozzle at the end of the arm 34, configured to switch between supplying the polishing fluid 36 and supplying the cleaning fluid 82.

[0022] 3A shows the polishing fluid line 68 and the cleaning fluid line 84 as passages within a solid body, this is not required. One or both fluid lines could also be provided by a pipe or flexible tube inside a cavity in the arm, or by a pipe or flexible tube on top of the arm.

[0023] The polishing liquid 36 may be a slurry containing abrasive particles. The polishing liquid supply arm 34 distributes the polishing liquid 36 through a nozzle 38. The nozzle 38 directs the polishing liquid 36 onto the surface of the polishing pad 10. When the polishing liquid 36 impacts the polishing pad 25, some of the polishing liquid 36 may bounce upward, forming droplets. Some of the polishing liquid 36 may flow down the polishing arm 34 and back onto the polishing pad 25, where they may collect in a pool, while some of the polishing liquid 36 may dry and accumulate on the polishing liquid supply arm 34, for example, on the inner surface 58 of the side wall 46, the ceiling 80, and the nozzle 38. With subsequent polishing operations, the polishing liquid 36 continues to accumulate on the polishing liquid supply arm 34, and the polishing liquid 36 may dry and accumulate further on the polishing liquid supply arm 34.

[0024] A polishing fluid supply arm cleaning tool 50 can be removably attached to the supply arm 34. Generally, the cleaning tool 50 forms a shell that covers at least the bottom of the enclosure 26 when installed on the supply arm. FIGS. 1B and 2 show the polishing fluid supply arm cleaning tool 50 installed on the polishing fluid supply arm 34. When installed, the cleaning tool 50 extends below the supply arm 34. In this configuration, the cleaning fluid 88 flows downward through the interior space 42 of the enclosure 26, impinges on the polishing fluid supply arm cleaning tool 50, and turns toward the ceiling 80 inside the polishing fluid supply arm 37, as shown in FIG. 1B.

[0025] The polishing fluid supply arm cleaning tool 50 has a floor 52 and a sidewall 54 extending upwardly from the floor 52. When installed, the floor 52 extends below and across the width of the polishing fluid supply arm 34, and the sidewall 54 extends along an outer surface 56 of the supply arm 36.

[0026] The cleaning tool 50 may include a number of retention tabs 60 that support the cleaning tool on the arm 34. Each retention tab 60 may extend from the side wall 54 and may be curved inward, i.e., toward the opposite side wall. Thus, when the cleaning tool 50 is slid onto the arm 34, the retention tabs 60 extend over the roof 44 of the polishing fluid delivery arm 34 to secure the cleaning tool 50 to the polishing fluid delivery arm 34 (see FIG. 3C).

[0027] The front end of the cleaning tool 50 is enclosed by a front cover 62. The front cover 62 can connect the side walls 54 and extend over the space between the side walls 54 in which the arms 34 fit. The front cover 62 prevents cleaning fluid from splashing out the front of the cleaning tool 50. The rear end of the cleaning tool 50 is open so that the cleaning tool can be slid onto the arms 34. The top of the cleaning tool 50, other than the front cover 62, can be left open.

[0028] 4, the polishing fluid cleaning tool 50 has a supply arm facing surface 48 that is shaped such that the polishing fluid supply arm cleaning tool 50 directs cleaning fluid from the polishing fluid supply arm 34 onto the inner surface 58 of the sidewall 46 of the polishing fluid supply arm 34, the ceiling 80 and the nozzle 38. The arm facing surface 48 can have one or more concavities 64 for directing the cleaning fluid back up towards the inner surfaces of the enclosure, e.g., the ceiling 80 and the inner surface 58 of the sidewall 46.

[0029] As shown in FIG. 4, the recesses 64 can be semicircular troughs. Alternatively, as shown in FIG. 5, the recesses 64 can be cylindrical. The curvature of the recesses 64 is configured such that the initial momentum of the downwardly moving droplets of cleaning fluid 88 carries the droplets 88 along the curvature and back up to the inner wall surface 58 and ceiling 88. In some implementations, a ridge 90 separates one recess 64 from another recess 64. Two or more ridges can separate one recess 64 from another recess. For example, a second ridge 92 can extend in a direction perpendicular to the ridge 90. The ridge 90 can be positioned directly beneath the nozzle 38 to split the spray of cleaning fluid 88 so that one portion of the spray is redirected toward one location and another portion of the spray is redirected toward another location, thereby directing half of the spray to each side of the inner surface 58 of the side wall 46 of the polishing fluid delivery arm 34, the ceiling 88 and the nozzle 38.

[0030] In some embodiments, arm facing surface 48 is the top surface of body 52 .

[0031] In some embodiments, the body 52 can be configured to receive an insert 66 (see FIG. 3C). The insert 66 is removably secured to the body 52. ​​For example, the insert 66 can be slid into a guide recess 48a (see FIG. 3B) on the top of the body 52. ​​The arm-facing surface 48 can be the upper surface of the insert 66 such that the insert 66 directs cleaning fluid from the polishing fluid supply arm 34 back to the inner surface 58 and the nozzle 38 of the polishing fluid supply arm.

[0032] 6A and 6B, instead of a body suspended from a tab, the abrasive fluid cleaning tool 50 can include an upper cover 110 and a lower cover 120 that can be separably secured together to form a shell that completely surrounds the abrasive fluid delivery arm 34 (along a cross section transverse to the length of the arm as shown in FIG. 6B). For example, the upper cover 110 can include a side wall 112 that extends downwardly from an edge of the ceiling piece 114, and the lower cover 120 can include a side wall 122 that extends upwardly from an edge of the floor piece 124. The side wall 112 of the upper cover 110 can be attached to the side wall 122 of the lower cover 120, for example, by a friction fit 130. Similarly, the side walls 112, 122 of the upper and lower covers 110, 120 can provide a front cover 62 for the cleaning tool 50. In assembly, the lower cover 110 can be placed beneath the polishing fluid supply arm 34 and the upper cover 120 can be lowered into place to mate with the lower cover 110 , thus enclosing the arm 34 .

[0033] 7A and 7B, the floor piece 124 of the bottom cover 120 (or the floor of the single piece tool of FIGS. 3A-3B) can include one or more channels 140 for excess cleaning fluid to flow out of the tool 50. In some embodiments, there are two channels 140, one on each side of the insert 48. The channels 140 can be adjacent to the sidewall 122. Specifically, two parallel linear protrusions 142 can extend from the floor piece 124, and the space between the protrusions 142 and the sidewall 122 can provide the channels 140. The insert 66 can fit between the two protrusions 142 of the floor piece 124. One end of each channel is blocked by the front cover 62, but cleaning fluid can flow out the opposite end.

[0034] The polishing fluid application arm cleaning tool 50 can be made of metal or plastic. For example, the cleaning tool 50 can be steel, aluminum, high density polyethylene, or a composite material.

[0035] FIG. 8 illustrates a method 600 for cleaning a polishing fluid delivery arm using a polishing fluid delivery arm cleaning tool. An insert can be inserted into the cleaning tool (802). The insert has an arm-facing surface that is shaped such that the insert directs cleaning fluid from the polishing fluid delivery arm back onto the surface of the polishing fluid delivery arm. The insert can have multiple pockets for directing the cleaning fluid. The polishing fluid delivery arm cleaning tool is placed onto the polishing fluid delivery arm such that the arm-facing surface extends below the enclosure of the polishing fluid delivery arm (804). The polishing fluid delivery arm cleaning tool retention tab is engaged over the top of the polishing fluid delivery arm. The cleaning fluid flows through the polishing fluid delivery arm (806). The arm-facing surface directs the cleaning fluid back onto the surface of the enclosure of the polishing fluid delivery arm (808). The polishing fluid delivery arm cleaning tool is removed from the polishing fluid delivery arm (810).

[0036] Although several embodiments have been described, it will be understood that various modifications may be made and, therefore, other embodiments are within the scope of the following claims.

Claims

1. a rotatable platen for supporting the polishing pad; a polishing fluid supply arm having an open-bottom enclosure and one or more ports for supplying polishing fluid and cleaning fluid downwardly onto the polishing pad through an interior space of the enclosure; a supply arm cleaning tool removably attached to the polishing liquid supply arm, the cleaning tool extending below the supply arm, the cleaning tool having a supply arm facing surface shaped such that the cleaning tool directs the cleaning fluid from the polishing liquid supply arm to a surface of the enclosure of the polishing liquid supply arm. Polishing assembly.

2. The assembly of claim 1 , wherein the arm facing surface has a plurality of recesses for directing the cleaning fluid.

3. The assembly of claim 1 , wherein the feed arm includes a ceiling with a sidewall extending downwardly from the ceiling, an interior space between the ceiling and the sidewall providing the enclosure.

4. The assembly of claim 3 , wherein the one or more nozzles are mounted to the ceiling of the feed arm.

5. The assembly of claim 4 , wherein the cleaning tool includes a body having a sidewall extending upwardly along an outer surface of the feed arm.

6. 6. The assembly of claim 5, wherein the cleaning tool includes an insert removably secured to the body, the arm-facing surface being an upper surface of the insert such that the insert directs the cleaning fluid from the polishing liquid supply arm back onto the surface of the polishing liquid supply arm.

7. 6. The assembly of claim 5, wherein said body extends below and across said arms, said arm-facing surface being an upper surface of said body.

8. The assembly of claim 4 , wherein the body includes a retention tab configured to extend above the ceiling of the supply arm to secure the body to the polishing fluid supply arm.

9. a supply arm cleaning tool configured to be removably secured to the polishing liquid supply arm, the supply arm cleaning tool including an arm facing surface configured to direct cleaning fluid ejected downward from the polishing liquid supply arm back onto an inner surface of an enclosure of the polishing liquid supply arm; Polishing fluid supply arm cleaning device.

10. The apparatus of claim 9 , wherein the arm facing surface includes a plurality of recesses for directing the cleaning fluid.

11. The apparatus of claim 9 , wherein the delivery arm cleaning tool includes a retention tab configured to extend over a top portion of the polishing fluid delivery arm.

12. The apparatus of claim 9 , wherein the feed arm cleaning tool includes a lower cover and an upper cover detachably securable to the lower cover.

13. a body configured to be removably secured to a polishing fluid delivery arm of a chemical mechanical polishing system; an insert removably secured to the body, the insert having an arm-facing surface configured to direct cleaning fluid from the polishing liquid supply arm back onto an inner surface of an enclosure of the polishing liquid supply arm; Abrasive fluid supply arm cleaning tool.

14. The tool of claim 13 , wherein the arm facing surface has a plurality of recesses for directing the cleaning fluid.

15. Positioning a polishing fluid delivery arm cleaning tool to extend below an enclosure of the polishing fluid delivery arm; flowing a cleaning fluid through the polishing fluid supply arm; directing the cleaning fluid from the polishing fluid supply arm back from a surface of the cleaning tool to a surface of the enclosure of the polishing fluid supply arm; and Removing the polishing liquid supply arm cleaning tool from the polishing liquid supply arm. A method for cleaning a polishing liquid supply arm comprising:

16. 16. The method of claim 15, further comprising placing an insert in the cleaning tool prior to installing the polishing liquid supply arm cleaning tool to extend beneath the enclosure of the polishing liquid supply arm, the insert having an arm-facing surface such that the insert directs the cleaning fluid from the polishing liquid supply arm back onto the surface of the polishing liquid supply arm.

17. The method of claim 15 further comprising securing the insert to the polishing fluid application arm cleaning tool.

18. The method of claim 15 , wherein the surface of the cleaning tool comprises a plurality of pockets for directing the cleaning fluid.

19. The method of claim 15 , wherein installing the cleaning tool includes fitting a retention tab onto a top portion of the polishing fluid dispensing arm.

20. The method of claim 15 , wherein installing the cleaning tool comprises securing the top cover to the bottom cover with the delivery arm disposed between the top cover and the bottom cover.

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