Cleaning system for polishing liquid transfer arms

Abstract

A polishing assembly includes a rotatable worktable for supporting a polishing pad; a polishing liquid transfer arm having an enclosure that opens at the bottom and one or more ports for transferring polishing liquid and cleaning fluid downward through the interior space of the enclosure to the polishing pad; and a transfer arm cleaning tool removably attached to the polishing liquid transfer arm, the cleaning tool extending below the transfer arm and having a surface facing the transfer arm, shaped such that the cleaning tool guides cleaning fluid from the polishing liquid transfer arm to the surface of the enclosure of the polishing liquid transfer arm.

Description

Technical Field

[0001] This disclosure relates to chemical mechanical polishing, and more particularly to the cleaning of a polishing liquid transfer arm that transfers polishing liquid to a polishing pad. Background Technology

[0002] Integrated circuits are typically formed on a substrate by sequentially depositing conductive layers, semiconductor layers, or insulating layers on a silicon wafer. One manufacturing step during integrated circuit fabrication is polishing the filler layer to expose the top surface of the underlying insulating layer, for example, vias, plugs, and lines that provide conductive paths between thin-film circuits formed on the substrate. For other applications, such as oxide polishing, the filler layer is planarized until a predetermined thickness is left on the non-planar surface. Furthermore, substrate surface planarization typically requires photolithography.

[0003] Chemical mechanical polishing (CMP) is an acceptable planarization method. This planarization method typically requires holding the substrate on a carrier or polishing head. The exposed surface of the substrate is usually placed against a rotating polishing pad. The carrier head provides a controlled load on the substrate to push it against the polishing pad. Polishing fluid is typically supplied to the surface of the polishing pad by a polishing fluid transfer arm. The polishing fluid transfer arm may also have nozzles for spraying cleaning fluid onto the polishing pad to remove slurry or debris from the polished surface. Summary of the Invention

[0004] In one aspect, a polishing assembly includes: a rotatable worktable for supporting a polishing pad; a polishing liquid transfer arm having an enclosure open at the bottom and one or more ports for transferring polishing liquid and cleaning fluid downward through the interior space of the enclosure to the polishing pad; and a transfer arm cleaning tool removably attached to the polishing liquid transfer arm, the cleaning tool extending below the transfer arm and having a surface facing the transfer arm, the surface facing the transfer arm being configured such that the cleaning tool directs the cleaning fluid from the polishing liquid transfer arm to the surface of the enclosure of the polishing liquid transfer arm.

[0005] In another aspect, a polishing liquid transfer arm cleaning tool includes: a transfer arm cleaning tool including an arm-facing surface configured to guide cleaning fluid projected downward from the polishing liquid transfer arm back to an inner surface of the enclosure of the polishing liquid transfer arm; and a retaining tab configured to secure the transfer arm cleaning tool to the polishing liquid transfer arm.

[0006] In another aspect, a polishing liquid transfer arm cleaning tool includes: a body configured to be removably attached to a polishing liquid transfer arm of a chemical mechanical polishing system; and an insert removably attached to the body. The insert has a surface facing the arm, the surface of which is configured to guide cleaning fluid from the polishing liquid transfer arm back to the inner surface of the enclosure of the polishing liquid transfer arm.

[0007] In another aspect, a method for cleaning a polishing liquid transfer arm includes: installing a polishing liquid transfer arm cleaning tool to extend below the enclosure of the polishing liquid transfer arm; allowing cleaning fluid to flow through the polishing liquid transfer arm; and guiding the cleaning fluid from the polishing liquid transfer arm away from the surface of the cleaning tool and back to the surface of the enclosure of the polishing liquid transfer arm.

[0008] Various embodiments may optionally include, but are not limited to, one or more of the following advantages: Polishing quality can be improved, for example, with less scratching and defects caused by dried abrasive particles accumulating from the polishing slurry detached from the polishing fluid transfer arm during the polishing process. Furthermore, the number of scrapped substrates due to defects can be reduced. Maintenance downtime for the polishing system can be significantly reduced. The quality of the cleaning process can be improved, and areas difficult to reach on the polishing fluid transfer arm can be more easily cleaned. This improves the productivity of the polishing system and reduces operator time by focusing less time on cleaning the polishing fluid transfer arm. The cleaning process can be quickly modified by adjusting the cleaning fluid pressure or composition.

[0009] Details of one or more embodiments are set forth in the accompanying drawings and the following description. Other aspects, features, and advantages will be apparent from the description and drawings and from the claims. Attached Figure Description

[0010] Figure 1A This shows a schematic cross-sectional view of a chemical mechanical polishing system.

[0011] Figure 1B A schematic cross-sectional view showing the polishing liquid transfer arm cleaning tool mounted on the polishing liquid transfer arm of the chemical mechanical polishing system shown in Figure 1.

[0012] Figure 2 A perspective view of a polishing liquid transfer arm cleaning tool installed on the polishing liquid transfer arm of a chemical mechanical polishing system.

[0013] Figure 3A Figure 1 shows a cross-sectional view of the polishing liquid transfer arm of the chemical mechanical polishing system.

[0014] Figure 3B show Figure 2A 3D view of a polishing liquid transfer arm cleaning tool.

[0015] Figure 3C A cross-sectional view of a polishing liquid transfer arm cleaning tool fixed to the polishing liquid transfer arm is shown.

[0016] Figure 4 show Figure 2 Rear perspective view of a polishing liquid transfer arm cleaning tool with a pocket.

[0017] Figure 5 show Figure 2 A cross-sectional view of the polishing liquid transfer arm cleaning tool.

[0018] Figure 6A A perspective view showing another embodiment of a polishing liquid transfer arm cleaning tool installed on the polishing liquid transfer arm of a chemical mechanical polishing system.

[0019] Figure 6B show Figure 6A A cross-sectional view of the polishing liquid transfer arm cleaning tool.

[0020] Figure 7A A perspective view showing the lower portion of another embodiment of the polishing liquid transfer arm cleaning tool.

[0021] Figure 7B show Figure 7A A cross-sectional view of the polishing liquid transfer arm cleaning tool.

[0022] Figure 8 This demonstrates a method for cleaning and polishing liquid transfer arms.

[0023] Similar reference numerals and symbols are used to indicate similar elements in the various figures. Detailed Implementation

[0024] During chemical mechanical polishing, polishing liquids, such as abrasive polishing slurries, are supplied to the surface of the polishing pad by a polishing liquid transfer arm. For example, the polishing liquid transfer arm may have nozzles that dispense the polishing liquid onto the surface of the polishing pad. As the polishing liquid impacts the polishing pad, some of the polishing liquid may deflect upwards and form airborne droplets. These droplets can accumulate on the polishing liquid transfer arm. Additionally, the polishing liquid can be scattered off the polishing pad through other components, such as a carrier head or conditioner head.

[0025] While some polishing fluid will flow off the transfer arm and be collected in the basin, some can dry and accumulate on the transfer arm. The accumulation of dried polishing fluid on the transfer arm over time has multiple detrimental effects. For example, abrasive particles in the polishing fluid can form aggregates that can later detach from the transfer arm and deposit on the polishing surface, creating a risk of scratches and defects. Significant non-productive time and operator effort are required to clean the polishing fluid transfer arm to prevent the accumulation of dried polishing fluid.

[0026] Polishing liquid transfer arm cleaning tools that can be easily attached to the polishing liquid transfer arm and do not require disassembly can mitigate these harmful effects.

[0027] Figure 1A The polishing system 20 is operable to polish substrate 10. The polishing system 20 includes: a rotatable platen 24 on which a polishing pad 25 is positioned; and a platen shield 26 surrounding the rotatable platen 24. The rotatable platen 24 is operable to rotate about axis 28. For example, a motor 29 can rotate a drive shaft 22 to rotate the rotatable platen 24.

[0028] 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 connected to a carrier head rotary motor 76 via a carrier drive shaft 74, allowing the carrier head to rotate about an axis 71. Furthermore, the carrier head 70 can laterally oscillate across the polishing pad 25, for example, by movement in radial slots in an actuator-driven carousel 72, by rotation of the carousel driven by a motor, or by fore-and-aft movement along a track driven by an actuator. In operation, the stage 24 rotates about its central axis 28, and the carrier head rotates about its central axis 71 and laterally translates across the top surface of the polishing pad 25.

[0029] As shown in Figure 1, the polishing system 20 also includes a polishing liquid delivery system 30. The polishing liquid delivery system 30 includes a polishing liquid delivery arm 34 supported by a base 32 on a worktable 24. A port 38, located at the end of the arm 34, is coupled to a polishing liquid source 78 (e.g., a reservoir) via a fluid line 68 (e.g., a pipe, tube, passageway, etc., through the solid body). The port 38 may be a nozzle. During polishing, the delivery arm 34 is operable to dispense polishing liquid 36 from the port 38. The flow of polishing liquid 36 through the fluid line 68 can be controlled by a liquid flow controller (LFC), which in turn can be controlled by a machine controller (e.g., a computer).

[0030] The polishing system 20 also includes one or more second ports 82, which may be located at the end of the arm 34 or positioned along the arm. The second ports 82 are coupled to a cleaning fluid source 86 (e.g., a reservoir) via a fluid line 84 (e.g., a pipe, tube, passageway, etc. through the solid body). During cleaning, the transfer arm 34 is operable to dispense cleaning fluid 88 from the ports 82. The second ports 82 may be nozzles, which can spray cleaning fluid onto the polishing pad 25. The cleaning fluid may be water, deionized water, or an isopropyl alcohol solution. The flow of cleaning fluid 88 through the fluid line 78 can be controlled by a liquid flow controller (LFC), which in turn can be controlled by a machine controller, such as a computer.

[0031] Reference Figure 3A The polishing fluid transfer arm 34 can form a enclosure 26, which is open at the bottom 40. In particular, the polishing fluid transfer arm 34 includes a roof 44 and sidewalls 46 extending downward from the roof 44. An interior space 42 is located between a ceiling 80 provided by the bottom of the roof 44 and the inner surface 58 of the sidewalls 46.

[0032] During the cleaning operation, the cleaning fluid 36 flows downwards, through the internal space 42 of the enclosure 26, and onto the polishing pad 25. The enclosure 26 is helpful in restraining the spraying of the cleaning fluid from the port 82 and / or exiting the polishing pad 25.

[0033] In other embodiments, the port in the polishing liquid transfer arm 34 can switch between transferring polishing liquid 36 and cleaning fluid 82. In other embodiments, the polishing liquid transfer arm 34 may have a nozzle, for example, a nozzle at the end of the arm 34, configured to switch between transferring polishing liquid 36 and cleaning fluid 82.

[0034] although Figure 3A The polishing fluid line 68 and cleaning fluid line 84 are illustrated as pathways within the solid body, but this is not mandatory. One or both fluid lines may be provided from inside the cavity of the arm, or from tubes or flexible conduits on top of the arm.

[0035] Polishing liquid 36 can be a slurry containing abrasive particles. Polishing liquid 36 is dispensed through nozzle 38 via polishing liquid transfer arm 34. Nozzle 38 guides polishing liquid 36 onto the surface of polishing pad 10. As polishing liquid 36 impacts polishing pad 25, some polishing liquid 36 may reflect upwards and form droplets. Although some polishing liquid 36 will flow away from polishing arm 34 and return to polishing pad 25 and can be collected in a basin, some polishing liquid 36 may dry and accumulate on polishing liquid transfer arm 34, for example, on the inner surface 58 of sidewall 46, on top surface 80, and on nozzle 38. Subsequent polishing operations will continue to deposit polishing liquid 36 on polishing liquid transfer arm 34, and polishing liquid 36 may dry and further accumulate on polishing liquid transfer arm 34.

[0036] The polishing liquid transfer arm cleaning tool 50 can be removably attached to the transfer arm 34. In general, the cleaning tool 50 forms a housing that, when mounted on the transfer arm, covers at least the bottom of the enclosure 26. Figure 1B and Figure 2 This shows a polishing liquid transfer arm cleaning tool 50 mounted on the polishing liquid transfer arm 34. When installed, the cleaning tool 50 extends below the transfer arm 34. In this configuration, the cleaning fluid 88 flows downwards, through the internal space 42 of the enclosure 26, and impacts the polishing liquid transfer arm cleaning tool 50, such as... Figure 1B As shown in the figure, it is redirected to the top surface 80 inside the polishing liquid transfer arm 37.

[0037] The polishing liquid transfer arm cleaning tool 50 has a floor 52 and a sidewall 54 extending upward from the floor 52. When installed, the floor 52 extends below the polishing liquid transfer arm 34 and across the width of the polishing liquid transfer arm 34, and the sidewall 54 extends along the outer surface 56 of the transfer arm 36.

[0038] The cleaning tool 50 may include a plurality of retaining tabs 60 to support the cleaning tool on the arm 34. Each retaining tab 60 may extend from the sidewall 54 and bend inward, i.e., bend toward the opposite sidewall. Thus, when the cleaning tool 50 slides onto the arm 34, the retaining tabs 60 extend over the top 44 of the polishing liquid transfer arm 34 to secure the cleaning tool 50 to the polishing liquid transfer arm 34 (see [link to relevant documentation]). Figure 3C ).

[0039] The front end of the cleaning tool 50 is enclosed by a front cover 62. The front cover 62 is connected to the sidewalls 54 and extends over the space between the sidewalls 54, into which the arm 34 is fitted. The front cover 62 prevents cleaning fluid from splashing out of the front of the cleaning tool 50. The rear end of the cleaning tool 50 is open, allowing the cleaning tool to slide onto the arm 34. Apart from the front cover 62, the cleaning tool 50 may be open at the top.

[0040] like Figure 4 As shown, the polishing fluid cleaning tool 50 has a surface 48 facing the transfer arm, configured such that the polishing fluid transfer arm cleaning tool 50 guides cleaning fluid from the polishing fluid transfer arm 34 onto the inner surface 58 of the sidewall 46, onto the top surface 80, and onto the nozzle 38 of the polishing fluid transfer arm 34. The arm-facing surface 48 may have one or more concave surfaces 64 to guide the cleaning fluid upward back to the inner surfaces of the enclosure (e.g., the top surface 80 and the inner surface 58 of the sidewall 46).

[0041] like Figure 4 As shown, concave surface 64 can be a semi-circular trough. Or, as... Figure 5 As shown, the concave surface 64 can be cylindrical. The curvature of the concave surface 64 is configured such that the initial momentum of the droplets of the downward-traveling cleaning fluid 88 will carry the droplets 88 around the curve and back upward to the inner surface 58 of the top surface 88 and the wall. In some embodiments, a ridge 90 separates one concave surface 64 from another. A concave surface 64 can be separated from another concave surface by more than one ridge. For example, a second ridge 92 can extend in a direction perpendicular to the ridge 90. The ridge 90 can be located directly below the nozzle 38 to split the spray of the cleaning fluid 88, such that a portion of the spray is redirected to one location and another portion is redirected to another location, such that half of the spray is directed to each side of the inner surface 58 of the polishing liquid transfer arm 34 nozzle 38 and the top surface 88 and the side wall 46.

[0042] In some implementations, the surface 48 facing the arm is the top surface of the body 52.

[0043] In some implementations, body 52 may be configured to receive insert 66 (see...) Figure 3C The insert 66 is removably secured to the body 52. ​​For example, the insert 66 can slide into the guide groove 48a on the top of the body 52 (see...). Figure 3B The surface 48 facing the arm can be the top surface of the insert 66, so that the insert 66 guides the cleaning fluid from the polishing fluid transfer arm 34 back to the inner surface 58 of the polishing fluid transfer arm and the nozzle 38.

[0044] Reference Figure 6A and6B Replacing the main body suspended from the earpiece, the polishing liquid cleaning tool 50 may include an upper cover 110 and a lower cover 120, which are detachably fixed together to form a complete surround (e.g.) Figure 6B As shown in the diagram, the housing of the polishing liquid transfer arm 34 is circumferentially transverse to the length of the arm. For example, the upper cover 110 may include a sidewall 112 extending downward from the edge of the top member 114, and the lower cover 120 may include a sidewall 122 extending upward from the edge of the base member 124. The sidewall 112 of the upper cover 110 may be attached to the sidewall 122 of the lower cover 120, for example, by friction fit 130. The front cover 62 of the cleaning tool 50 may similarly be provided by the sidewalls 112, 122 of the upper and lower covers 110, 120. For assembly, the lower cover 110 may be positioned below the polishing liquid transfer arm 34, and the upper cover 120 may be lowered into position to engage with the lower cover 110, thereby enclosing the arm 34.

[0045] Reference Figure 7A and 7B The bottom plate component 124 of the lower cover 120 (or Figures 3A-3B The base plate of the single-piece tool 50 may include one or more channels 140 for draining excess cleaning fluid from the tool 50. In some embodiments, there are two channels 140, each on a separate side of the insert 48. The channels 140 may be adjacent to the sidewalls 122. In particular, two parallel linear protrusions 142 may extend from the base plate member 124, and the space between the protrusions 142 and the sidewalls 122 provides the channels 140. The insert 66 may be fitted onto the base plate member 124 and between the two protrusions 142. One end of each channel is blocked by a front cover 62, but cleaning fluid can drain from the opposite end.

[0046] The polishing liquid transfer arm cleaning tool 50 can be made of metal or plastic. For example, the cleaning tool 50 can be made of steel, aluminum, high-density polyethylene, or composite materials.

[0047] Figure 8A method 600 for cleaning a polishing liquid transfer arm using a polishing liquid transfer arm cleaning tool is shown. An insert is inserted into the cleaning tool (802). The insert has an arm-facing surface configured such that it guides cleaning fluid from the polishing liquid transfer arm back to the surface of the polishing liquid transfer arm. The insert may have multiple recesses to guide the cleaning fluid. The polishing liquid transfer arm cleaning tool is mounted on the polishing liquid transfer arm such that the arm-facing surface extends below the enclosure of the polishing liquid transfer arm (804). The polishing liquid transfer arm cleaning tool retains lugs engaged above the top of the polishing liquid transfer arm. Cleaning fluid flows through the polishing liquid transfer arm (806). The cleaning fluid is guided by the arm-facing surface back to the surface of the enclosure of the polishing liquid transfer arm (808). The polishing liquid transfer arm cleaning tool is removed from the polishing liquid transfer arm (810).

[0048] Several embodiments have been described. However, it should be understood that various modifications can be made. Therefore, other embodiments are within the scope of the appended claims.

Claims

1. A polishing assembly, comprising: A rotating worktable is used to support the polishing pad; A polishing liquid transfer arm has an enclosure open at the bottom and one or more ports for transferring polishing liquid and cleaning fluid downward through the interior space of the enclosure to the polishing pad; and A transfer arm cleaning tool is removably attached to the polishing liquid transfer arm, the transfer arm cleaning tool extending below the polishing liquid transfer arm and having a surface facing the polishing liquid transfer arm, the surface facing the polishing liquid transfer arm being configured such that the transfer arm cleaning tool directs the cleaning fluid from the polishing liquid transfer arm to the inner surface of the enclosure of the polishing liquid transfer arm to clean the inner surface of the enclosure or the one or more ports.

2. The component of claim 1, wherein the surface facing the polishing liquid transfer arm has a plurality of concave surfaces to guide the cleaning fluid.

3. The assembly of claim 1, wherein the polishing liquid transfer arm includes a top surface providing the enclosure and a sidewall extending downward from the top surface, and an internal space between the top surface and the sidewall.

4. The component of claim 3, wherein the one or more ports include one or more nozzles attached to the top surface of the polishing liquid transfer arm.

5. The component of claim 4, wherein the transfer arm cleaning tool includes a body having a sidewall extending upward along the outer surface of the polishing liquid transfer arm.

6. The component of claim 5, wherein the transfer arm cleaning tool includes a plug removably attached to the body, and wherein the surface facing the polishing liquid transfer arm is the top surface of the plug, such that the plug guides the cleaning fluid from the polishing liquid transfer arm back to the surface of the polishing liquid transfer arm.

7. The component of claim 5, wherein the body extends below and across the polishing liquid transfer arm, and wherein the surface facing the polishing liquid transfer arm is the top surface of the body.

8. The component of claim 4, wherein the transfer arm cleaning tool includes a body including a retaining lug configured to extend over the top surface of the polishing liquid transfer arm to secure the body to the polishing liquid transfer arm.

9. A polishing liquid transfer arm cleaning device, comprising: A transfer arm cleaning tool is configured to be removably attached to a polishing liquid transfer arm having an open enclosure at the bottom and one or more ports for transferring polishing liquid and cleaning fluid downward through the interior space of the enclosure to a polishing pad. The transfer arm cleaning tool includes a surface facing the polishing liquid transfer arm, the surface of which is configured to guide the cleaning fluid projected downward from the polishing liquid transfer arm back to the inner surface of the enclosure of the polishing liquid transfer arm to clean the inner surface of the enclosure or the one or more ports.

10. The apparatus of claim 9, wherein the surface facing the polishing liquid transfer arm includes a plurality of concave surfaces to guide the cleaning fluid.

11. The apparatus of claim 9, wherein the transfer arm cleaning tool includes a retaining tab configured to extend over the top of the polishing liquid transfer arm.

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

13. A polishing liquid transfer arm cleaning tool, comprising: The main body is configured as a polishing liquid transfer arm for removable attachment to a chemical mechanical polishing system; and An insert, removably fixed to the body, having a surface facing the polishing liquid transfer arm, the surface of the polishing liquid transfer arm being configured to guide cleaning fluid from the polishing liquid transfer arm back to the inner surface of the enclosure of the polishing liquid transfer arm.

14. The tool of claim 13, wherein the surface facing the polishing liquid transfer arm has a plurality of concave surfaces to guide the cleaning fluid.

15. A method for cleaning a polishing liquid transfer arm, comprising the following steps: A polishing liquid transfer arm cleaning tool is mounted on a polishing liquid transfer arm having an open enclosure at the bottom and one or more ports for transferring polishing liquid and cleaning fluid downward through the interior space of the enclosure to a polishing pad. The polishing liquid transfer arm cleaning tool is mounted to extend below the enclosure of the polishing liquid transfer arm. Allow the cleaning fluid to flow through the polishing liquid transfer arm; The cleaning fluid from the polishing fluid transfer arm is directed away from the surface of the polishing fluid transfer arm cleaning tool and back to the inner surface of the enclosure of the polishing fluid transfer arm to clean the inner surface of the enclosure or the one or more ports. and Remove the polishing liquid transfer arm cleaning tool from the polishing liquid transfer arm.

16. The method of claim 15, further comprising the following steps: Before installing the polishing liquid transfer arm cleaning tool to extend below the enclosure of the polishing liquid transfer arm, an insert is provided into the polishing liquid transfer arm cleaning tool, wherein the insert has a surface facing the polishing liquid transfer arm such that the insert guides the cleaning fluid from the polishing liquid transfer arm back to the surface of the polishing liquid transfer arm.

17. The method of claim 16, further comprising the following steps: The plug is secured to the polishing liquid transfer arm cleaning tool.

18. The method of claim 15, wherein the surface of the polishing liquid transfer arm cleaning tool includes a plurality of recesses to guide the cleaning fluid.

19. The method of claim 15, wherein installing the polishing liquid transfer arm cleaning tool comprises the following steps: A retaining lug is fitted on top of the polishing liquid transfer arm.

20. The method of claim 15, wherein installing the polishing liquid transfer arm cleaning tool comprises the following steps: The upper cover is secured to the lower cover, and the polishing liquid transfer arm is located between the upper cover and the lower cover.

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