Cleaning system for polishing fluid 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] The present disclosure relates to chemical mechanical polishing, and more particularly to the cleaning of a polishing liquid supply arm that supplies a polishing liquid onto a polishing pad.

Background Art

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

[0003] Chemical mechanical polishing (CMP) is an accepted planarization method. In this planarization method, it is usually necessary to mount the substrate on a carrier head or a polishing head. Usually, the exposed surface of the substrate is applied to a rotating polishing pad. The carrier head presses the substrate against the polishing pad by applying a controllable load to the substrate. Usually, a polishing liquid is supplied to the surface of the polishing pad by a polishing liquid supply arm. The polishing liquid supply arm may further have a nozzle for spraying a rinse fluid onto the polishing pad to remove slurry or debris from the polishing surface.

Summary of the Invention

[0004] In one embodiment, the polishing assembly includes a rotatable platen for supporting a polishing pad, an enclosure with an open bottom, and a polishing fluid delivery arm having one or more ports for supplying polishing fluid and cleaning fluid downward onto the polishing pad through the internal space of the enclosure, and a delivery arm cleaning tool detachably attached to the polishing fluid delivery arm, the cleaning tool extending downward from the delivery arm, and the cleaning tool having a delivery arm-facing surface shaped such that the cleaning tool guides the cleaning fluid from the polishing fluid delivery arm to the surface of the enclosure of the polishing fluid delivery arm.

[0005] In another embodiment, the polishing fluid supply arm cleaning tool includes an arm-facing surface having a shape that guides the cleaning fluid ejected downward from the polishing fluid supply arm back into the inner surface of the enclosure of the polishing fluid supply arm, and a retaining tab configured to secure the supply arm cleaning tool to the polishing fluid supply arm.

[0006] In another embodiment, the polishing fluid supply arm cleaning tool includes a body configured to be removably fixed to the polishing fluid supply arm of a chemical mechanical polishing system, and an insert removably fixed to the body. The insert has an arm-facing surface, which is shaped to guide the cleaning fluid from the polishing fluid supply arm back into the inner surface of the enclosure of the polishing fluid supply arm.

[0007] In another embodiment, a method for cleaning a polishing fluid supply arm includes positioning a polishing fluid supply arm cleaning tool so as to extend below the enclosure of the polishing fluid supply arm, flowing a cleaning fluid through the polishing fluid supply arm, and guiding the cleaning fluid from the polishing fluid supply arm back from the surface of the cleaning tool to the surface of the enclosure of the polishing fluid supply arm.

[0008] The embodiments may optionally include one or more of the following advantages: The quality of polishing may be improved, for example, by reducing scratches and defects caused by dry abrasive particles derived from polishing slurry deposits separated from the polishing fluid supply arm during the polishing process. Furthermore, the amount of substrate discarded due to defects can be reduced. The downtime of the polishing system due to maintenance can be significantly reduced. The quality of the cleaning process may be improved, making it easier to clean hard-to-reach areas of the polishing fluid supply arm. This reduces the time spent on the polishing fluid supply arm cleaning process, thereby improving the productivity of the polishing system and reducing operator time. The cleaning process can be quickly modified by adjusting the cleaning fluid pressure or cleaning fluid composition.

[0009] Details of one or more embodiments are shown in the accompanying drawings and the following description. Other embodiments, features, and advantages will become apparent from this description and drawings, as well as from the claims. [Brief explanation of the drawing]

[0010] [Figure 1A] This is a schematic cross-sectional view of a chemical mechanical polishing system. [Figure 1B] Figure 1 is a schematic cross-sectional view of a polishing fluid supply arm cleaning tool installed on the polishing fluid supply arm of the chemical mechanical polishing system. [Figure 2] This is a perspective view of a cleaning tool for the polishing fluid supply arm, which is mounted on the polishing fluid supply arm of a chemical mechanical polishing system. [Figure 3A] Figure 1 is a cross-sectional view of the polishing fluid supply arm of a chemical mechanical polishing system. [Figure 3B] Figure 2 is a perspective view of the polishing fluid supply arm cleaning tool. [Figure 3C] This is a cross diagram of the polishing fluid supply arm cleaning tool fixed to the polishing fluid supply arm. [Figure 4] Figure 2 is a rear perspective view of the polishing fluid supply arm cleaning tool equipped with a pocket. [Figure 5] Figure 2 is a cross-sectional view of the polishing fluid supply arm cleaning tool. [Figure 6A] This is a perspective view of another embodiment of a polishing fluid supply arm cleaning tool installed on the polishing fluid supply arm of a chemical mechanical polishing system. [Figure 6B] Figure 6A is a cross-sectional view of the polishing fluid supply arm cleaning tool. [Figure 7A] This is a lower cross-sectional perspective view of another embodiment of the polishing fluid supply arm cleaning tool. [Figure 7B] Figure 7A is a cross-sectional view of the polishing fluid supply arm cleaning tool. [Figure 8] This diagram shows a method for cleaning the polishing fluid supply arm. [Modes for carrying out the invention]

[0011] The same reference numerals and symbols used in various drawings refer to the same element.

[0012] During chemical mechanical polishing, a polishing fluid, such as abrasive polishing slurry, is supplied to the surface of the polishing pad by a polishing fluid supply arm. For example, the polishing fluid supply arm may have nozzles that distribute the polishing fluid to the surface of the polishing pad. When the polishing fluid collides with the polishing pad, some of it may be redirected upwards, forming droplets that float in the air. These droplets may accumulate on the polishing fluid supply arm. Furthermore, the polishing fluid may be splashed from the polishing pad by other components, such as a carrier head or a conditioner head.

[0013] Some of the polishing fluid flows out of the supply arm and can be collected in the basin, but some of the polishing fluid can dry and accumulate on the supply arm. The accumulation of dried polishing fluid on the supply arm over time has many detrimental effects. For example, the abrasive particles in the polishing fluid can form clumps. These clumps can later detach from the supply arm and accumulate on the polishing surface, thus creating a risk of scratch formation and defects. Cleaning the polishing fluid supply arm to prevent the accumulation of dried polishing fluid requires a considerable amount of unproductive time and operator effort.

[0014] A cleaning tool for the polishing fluid supply arm, which can be easily attached to the polishing fluid supply arm and does not require disassembly of the equipment, can mitigate these harmful effects.

[0015] Figure 1A shows a polishing system 20 that is 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 surrounding the rotatable platen 24. The rotatable platen 24 is operable to rotate around 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 that is operable to hold the substrate 10 relative to the polishing pad 25. The carrier head 70 is suspended from a support structure 72, such as a carousel or track, and is connected by a carrier drive shaft 74 to a carrier head rotary motor 76 so that the carrier head can rotate around an axis 71. Furthermore, the carrier head 70 can reciprocate laterally across the polishing pad 25, for example by moving in the radial grooves of the carousel 72 when driven by an actuator, or by the rotation of the carousel when driven by a motor, or by moving back and forth along a track when driven by an actuator. During operation, the platen 24 rotates around its central axis 28, and the carrier head rotates around its central axis 71 and translates laterally across the upper surface of the polishing pad 25.

[0017] As shown in Figure 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 on the platen 24 by a base 32. A port 38, which may be located at the end of the arm 34, is connected to a polishing fluid source 78, such as a reservoir, by a fluid conduit 68, such as a tube, pipe, or solid passage. The port 38 can be a nozzle. During polishing, the supply arm 34 is operable to distribute polishing fluid 36 from the port 38. The flow rate of polishing fluid 36 through the fluid conduit 68 can be controlled by a liquid flow controller (LFC), which can be controlled by a machine controller, such as a computer.

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

[0019] Referring to FIG. 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 side walls 46 extending downward from the roof 44. There is an internal space 42 between a ceiling 80 provided by the bottom of the roof 44 and an inner surface 58 of the side walls 46.

[0020] During the cleaning operation, the cleaning fluid 36 flows downward onto the polishing pad 25 through the internal space 42 of the enclosure 26. The enclosure 26 can help suppress splashing of the cleaning fluid from the port 82 and / or the polishing pad 25.

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

[0022] Figure 3A shows the polishing fluid conduit 68 and the cleaning fluid conduit 84 as passages within the solid, but this is not mandatory. One or both fluid conduits can also be provided by pipes or flexible tubes inside the cavity of the arm, or by pipes or flexible tubes on top of the arm.

[0023] The polishing fluid 36 can be a slurry containing abrasive particles. The polishing fluid supply arm 34 distributes the polishing fluid 36 through a nozzle 38. The nozzle 38 guides the polishing fluid 36 to the surface of the polishing pad 10. When the polishing fluid 36 hits the polishing pad 25, some of the polishing fluid 36 may splash upward, forming droplets. Some of the polishing fluid 36 may flow down from the polishing arm 34 and return to the polishing pad 25, collecting them in a liquid reservoir, but some of the polishing fluid 36 may dry and accumulate on the polishing fluid supply arm 34, for example, on the inner surface 58 of the side wall 46, the ceiling 80 and the nozzle 38. Due to subsequent polishing operations, the polishing fluid 36 continues to accumulate on the polishing fluid supply arm 34, and the polishing fluid 36 may dry and accumulate further on the polishing fluid supply arm 34.

[0024] A polishing fluid supply arm cleaning tool 50 can be detachably 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. Figures 1B and 12 show the polishing fluid supply arm cleaning tool 50 installed on the polishing fluid supply arm 34. When installed, the cleaning tool 50 extends downward from the supply arm 34. In this configuration, the cleaning fluid 88 flows downward through the internal space 42 of the enclosure 26, as shown in Figure 1B, collides with the polishing fluid supply arm cleaning tool 50, changes direction, and heads towards the ceiling 80 inside the polishing fluid supply arm 37.

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

[0026] The cleaning tool 50 may include a number of retaining tabs 60 that support the cleaning tool on the arm 34. Each retaining tab 60 may extend from the side wall 54 and curve inward, i.e., curve toward the opposite side wall. Thus, when the cleaning tool 50 is slid onto the arm 34, the retaining tabs 60 extend over the roof 44 of the polishing fluid supply arm 34, securing the cleaning tool 50 to the polishing fluid supply arm 34 (see Figure 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 extends over the space between the side walls 54 in which the arm 34 is housed. The front cover 62 prevents the cleaning fluid from splashing out from 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 arm 34. The top of the cleaning tool 50, other than the front cover 62, can be left open.

[0028] As shown in Figure 4, the polishing fluid cleaning tool 50 has a supply arm opposing surface 48, which is shaped such that the polishing fluid supply arm cleaning tool 50 guides the cleaning fluid from the polishing fluid supply arm 34 onto the inner surface 58 of the side wall 46 of the polishing fluid supply arm 34, the ceiling 80 and the nozzle 38. The arm opposing surface 48 may have one or more concavities 64 to guide the cleaning fluid back upward toward the inner surface of the enclosure, for example, the ceiling 80 and the inner surface 58 of the side wall 46.

[0029] As shown in Figure 4, the recess 64 can be a semicircular trough. Alternatively, as shown in Figure 5, the recess 64 can be cylindrical. The curvature of the recess 64 is configured such that the initial momentum of droplets of the cleaning fluid 88 moving downwards carries the droplets 88 along the curve, causing them to reverse upwards and reach the inner surface 58 of the wall and the ceiling 88. In some embodiments, a ridge 90 separates one recess 64 from another recess 64. Two or more ridges can separate a recess 64 from another recess. For example, a second ridge 92 can extend perpendicular to the ridge 90. The ridge 90 can be positioned directly below the nozzle 38 in order to divide the spray of the cleaning fluid 88 so that one portion of the spray changes direction and heads toward one position, and another portion of the spray changes direction and heads toward another position, so that half of the spray is directed toward the inner surface 58 of the side wall 46 of the polishing fluid supply arm 34, the ceiling 88, and the nozzle 38, respectively.

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

[0031] In some embodiments, the body 52 can be configured to receive the insert 66 (see Figure 3C). The insert 66 is removably fixed to the body 52. ​​For example, the insert 66 can be slid into a guide recess 48a on the upper part of the body 52 (see Figure 3B). The arm-facing surface 48 can be the upper surface of the insert 66 such that the insert 66 guides the 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] Referring to Figures 6A and 6B, instead of a body suspended from a tab, the polishing fluid cleaning tool 50 may include an upper cover 110 and a lower cover 120, which can be detachably fixed together to form a shell that completely encloses the polishing fluid supply arm 34 (along a cross section transverse to the length of the arm, as shown in Figure 6B). For example, the upper cover 110 may include a side wall 112 extending downward from the edge of the ceiling piece 114, and the lower cover 120 may include a side wall 122 extending upward from the edge of the floor piece 124. The side wall 112 of the upper cover 110 may be attached to the side wall 122 of the lower cover 120, for example, by a friction fit 130. Similarly, the side walls 112 and 122 of the upper and lower covers 110 and 120 may provide a front cover 62 for the cleaning tool 50. During assembly, the lower cover 110 is placed below the polishing fluid supply arm 34, and the upper cover 120 is lowered to a predetermined position so as to fit with the lower cover 110, thus enclosing the arm 34.

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

[0034] The polishing fluid supply 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 a composite material.

[0035] Figure 8 shows a method 600 for cleaning a polishing fluid supply arm using a polishing fluid supply arm cleaning tool. An insert can be inserted into the cleaning tool (802). The insert has an arm-facing surface, which is shaped to guide the cleaning fluid from the polishing fluid supply arm back to the surface of the polishing fluid supply arm. The insert may have multiple pockets for guiding the cleaning fluid. The polishing fluid supply arm cleaning tool is placed on the polishing fluid supply arm so that the arm-facing surface extends below the enclosure of the polishing fluid supply arm (804). The polishing fluid supply arm cleaning tool retaining tab is engaged over the top of the polishing fluid supply arm. The cleaning fluid flows through the polishing fluid supply arm (806). The arm-facing surface guides the cleaning fluid back to the surface of the enclosure of the polishing fluid supply arm (808). The polishing fluid supply arm cleaning tool is removed from the polishing fluid supply arm (810).

[0036] Several embodiments have been described. Nevertheless, it will be understood that various modifications can be made. Therefore, other embodiments are included in the claims below.

Claims

1. A cleaning kit for polishing fluid supply arms, The top cover is detachably fitted onto the top of the polishing fluid supply arm, A lower cover is detachably fitted into the lower part of the polishing fluid supply arm and is detachably attached to the upper cover, forming a shell that surrounds the polishing fluid supply arm. The insert is removably supported by the aforementioned lower cover, Includes, The insert has an arm-facing surface formed to return the cleaning fluid ejected downward from the polishing fluid supply arm toward the polishing fluid supply arm. Polishing fluid supply arm cleaning kit.

2. The kit according to claim 1, wherein the upper cover and the lower cover are detachably fixed by friction fitting.

3. The kit according to claim 1, wherein the lower cover includes at least one channel for draining cleaning fluid from the open end of the shell.

4. The kit according to claim 1, wherein the floor of the lower cover includes a first linear projection extending parallel to the first side wall of the lower cover and a second linear projection extending parallel to the second side wall of the lower cover, the space between the first linear projection and the first side wall providing a first channel, and the space between the second linear projection and the second side wall providing a second channel.

5. The kit according to claim 4, wherein the insert fits into the floor of the lower cover between the first linear projection and the second linear projection.

6. The shell is closed by covering the end of the polishing fluid supply arm. The kit according to claim 1.

7. The kit according to claim 1, wherein the arm-facing surface has a plurality of recesses for returning the cleaning fluid toward the polishing fluid supply arm.

8. The kit according to claim 7, wherein the plurality of recesses are arranged parallel to each other and include two troughs extending parallel to the side wall of the shell.

9. The kit according to claim 8, wherein the ridge between the two troughs is positioned below the cleaning fluid nozzle of the polishing fluid supply arm.

10. A cleaning kit for polishing fluid supply arms, The top cover is detachably fitted onto the top of the polishing fluid supply arm, A lower cover that is removably fitted into the lower part of the polishing fluid supply arm and detachably attached to the upper cover, forming a shell surrounding the polishing fluid supply arm, wherein the shell has a closed end at the end of the polishing fluid supply arm and an open end on the opposite side, Includes, The lower cover includes at least one channel for draining cleaning fluid supplied by a polishing fluid supply arm from the open end of the shell. Polishing fluid supply arm cleaning kit.

11. The kit according to claim 10, wherein the floor of the lower cover includes a first linear projection extending parallel to the first side wall of the lower cover and a second linear projection extending parallel to the second side wall of the lower cover, the space between the first linear projection and the first side wall providing a first channel, and the space between the second linear projection and the second side wall providing a second channel.

12. The main body, The polishing fluid supply arm comprises a floor, a pair of side walls, and an enclosure with an open bottom, and has tabs extending upward from the side walls on top of the enclosure, which removably secure the main body to the polishing fluid supply arm. When the main body is installed on the polishing fluid supply arm, the main body and the polishing fluid supply arm form a shell surrounding the enclosure. The main unit and An insert is detachably fixed to the main body, Includes, The insert has an arm-facing surface having a shape that guides the cleaning fluid from the polishing fluid supply arm back to the inner surface of the enclosure of the polishing fluid supply arm. Polishing fluid supply arm cleaning tool.

13. The kit according to claim 12, wherein the arm-facing surface has a plurality of recesses for returning the cleaning fluid toward the inner surface of the enclosure.

14. The kit according to claim 13, wherein the plurality of recesses include two troughs that are arranged parallel to each other and extend parallel to the side wall of the shell.

Images