Use of steam for preheating or cleaning cmp components

Abstract

A temperature control method for a chemical mechanical polishing system includes the step of directing a vapor-containing gas from an orifice onto a component to clean the component or raise a temperature of the component to an elevated temperature when the component in the polishing system is spaced apart from a polishing pad in the polishing system. Moving the component into contact with the polishing pad may occur before the component returns to ambient temperature.

Description

[0001] This application is a divisional application of a Chinese patent application (PCT application number PCT / US2020 / 034927) with an application date of May 28, 2020, application number 202080038768.1, and name “Using steam for preheating or cleaning CMP parts”. Technical Field

[0002] The present disclosure relates to chemical mechanical polishing (CMP), and more particularly to using steam for cleaning or preheating during CMP. Background Art

[0003] Integrated circuits are typically formed on a substrate by sequentially depositing a conductive layer, a semiconductive layer, or an insulating layer on a semiconductor wafer. Various manufacturing processes require planarization of the layers on the substrate. For example, one manufacturing step includes depositing a filler layer on a non-planar surface and planarizing the filler layer. For some applications, the filler layer is planarized until the top surface of the patterned layer is exposed. For example, a metal layer can be deposited on a patterned insulating layer to fill the grooves and holes in the insulating layer. After planarization, the remaining portions of the metal in the grooves and holes of the patterned layer form vias, plugs, and lines to provide conductive paths between thin film circuits on the substrate. As another example, a dielectric layer can be deposited on the patterned conductive layer and then planarized to achieve subsequent photolithography steps.

[0004] Chemical mechanical polishing (CMP) is an acceptable planarization method. This planarization method generally requires mounting the substrate on a carrier head. The exposed surface of the substrate is generally placed against a rotating polishing pad. The carrier head provides a controllable load on the substrate to push the substrate against the polishing pad. A polishing slurry having abrasive particles is generally supplied to the surface of the polishing pad. Summary of the invention

[0005] In one aspect, a temperature control method for a chemical mechanical polishing system includes the steps of directing a gas containing steam from an orifice onto a component in the polishing system to raise the temperature of the component to an elevated temperature while the component is separated from a polishing pad in the polishing system, and moving the component into contact with the polishing pad before the component is returned to ambient temperature.

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

[0007] The temperature of the component may be measured as steam is directed onto the component, and the steam may be stopped when the component reaches a target temperature.The temperature of the polishing pad may be measured, and the target temperature may be calculated based on the measured temperature.

[0008] A timer can be set and the steam stopped when the timer expires.

[0009] When the component is placed in contact with the polishing pad, the temperature of the component can be approximately equal to the temperature of the polishing pad. The elevated temperature can be greater than the temperature of the polishing pad.

[0010] The gas may have a temperature of 70-100° C. The steam may be dry steam. The gas may consist of steam.

[0011] The component can be positioned to be separated from the polishing pad to direct steam onto the component at the treatment station. The component can be rotated in the treatment station while steam is directed onto the component. The component can be moved vertically in the treatment station while steam is directed onto the component.

[0012] The component may include a carrier head or a substrate to be polished. Steam may be directed onto the component at a substrate transfer station. Steam may be directed onto the component at an inter-platen station.

[0013] The component may include a regulator disc or a regulator head. Steam may be directed onto the component at the regulator disc cleaning cup.

[0014] In another aspect, a chemical mechanical polishing system includes: a platen supporting a polishing pad; a boiler; a treatment station separated from the polishing pad and having a plurality of nozzles to direct steam from the boiler to a body positioned in the treatment station; an actuator to move a component from the treatment station to contact with the polishing pad; and a controller configured to cause the treatment station to direct steam onto the component to raise the temperature of the component to an elevated temperature, and to cause the actuator to move the component from the treatment station to contact with the polishing pad before the component returns to ambient temperature.

[0015] Implementations may include one or more of the following features.

[0016] The component may include a carrier head or a base plate. The component may include an adjuster head or an adjuster disk.

[0017] In another aspect, a cleaning method for a chemical mechanical polishing system includes the steps of directing a gas containing steam from an orifice onto a component in the polishing system to clean the component while the component is separated from a polishing pad in the polishing system, and moving the component into contact with the polishing pad.

[0018] Implementations may include one or more of the following features.

[0019] It is possible to set a timer and stop the steam when the timer expires.

[0020] The gas may have a temperature of 70-100° C. The gas may have a temperature of 80-100° C. The steam may include dry steam. The gas may consist of steam. The gas may include a mixture of steam and atmospheric air.

[0021] The component can be positioned in the treatment station and can be separated from the polishing pad to direct steam onto the component at the treatment station. The component can rotate in the treatment station while steam is directed onto the component. The component can move vertically in the treatment station while steam is directed onto the component.

[0022] The component may include a carrier head or a substrate to be polished. Steam may be directed onto the component at a substrate transfer station. Steam may be directed onto the component at an inter-platen station.

[0023] The component may include a regulator disc or a regulator head. Steam may be directed onto the component at the regulator disc cleaning cup.

[0024] Cleaning components may include removing congealed slurry. Cleaning components may include removing congealed polishing debris.

[0025] In one aspect, a chemical mechanical polishing system includes: a platen supporting a polishing pad; a boiler; a treatment station separated from the polishing pad, the treatment station having a plurality of nozzles to direct steam from the boiler to a body positioned in the treatment station; an actuator to move a component from the treatment station to contact the polishing pad; and a controller configured to cause the treatment station to direct steam onto the component to raise the temperature of the component to an elevated temperature, and to cause the actuator to move the component from the treatment station to contact the polishing pad.

[0026] Implementations may include one or more of the following features.

[0027] The components may include a carrier head or a substrate.

[0028] The components may include a regulator head or a regulator disk.

[0029] Possible advantages may include, but are not limited to, one or more of the following.

[0030] Steam (i.e., gaseous H2O produced by boiling) can be produced in sufficient quantities with low contaminant levels. In addition, the steam generator can produce steam that is substantially a pure gas, e.g., with little or no liquid suspended in the steam. Such steam (also known as dry steam) can provide a gaseous form of H2O that has higher energy transfer and lower liquid content than other steam alternatives, such as flash steam.

[0031] Various components of CMP equipment can be cleaned quickly and efficiently. Steam can be more effective than liquid water in dissolving or otherwise removing polishing byproducts, dried slurry, debris, etc. from the surface of the polishing system. Therefore, defects on the substrate can be reduced.

[0032] Various components of the CMP equipment can be preheated. The temperature variation across the polishing pad and therefore across the substrate can be reduced, thereby reducing wafer-to-wafer non-uniformity (WIWNU). The temperature variation during the polishing operation can be reduced. This can improve the predictability of polishing during the CMP process. The temperature variation from one polishing operation to another can be reduced. This can improve wafer-to-wafer uniformity.

[0033] The details of one or more implementations are described 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 DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic plan view of an example of a polishing apparatus.

[0035] Figure 2A is a schematic cross-sectional view of an example carrier head vapor handling assembly.

[0036] Figure 2B is a schematic cross-sectional view of an example conditioning head steam handling assembly.

[0037] Figure 3A is a schematic cross-sectional view of an example of a polishing station of a polishing apparatus.

[0038] Figure 3B is a schematic top view of an example polishing station of a chemical mechanical polishing apparatus. DETAILED DESCRIPTION

[0039] Chemical mechanical polishing operates through a combination of mechanical abrasion and chemical etching at the interface between the substrate, polishing slurry, and polishing pad. During the polishing process, a significant amount of heat is generated due to the friction between the substrate surface and the polishing pad. In addition, some processes also include an in-situ pad conditioning step in which a conditioning disk (e.g., a disk coated with abrasive diamond particles) is pressed against the rotating polishing pad to condition and texture the polishing pad surface. The abrasiveness of the conditioning process can also generate heat. For example, in a process with a nominal downforce of 2 psi and In a typical one-minute copper CMP process with a removal rate of 1.34 W / min, the surface temperature of the polyurethane polishing pad can rise by about 30°C.

[0040] On the other hand, if the polishing pad has been heated by a previous polishing operation, when a new substrate is initially lowered into contact with the polishing pad, it is at a lower temperature and can therefore act as a heat sink. Similarly, the slurry dispensed onto the polishing pad can act as a heat sink. Overall, these effects cause the temperature of the polishing pad to vary both spatially and temporally.

[0041] Both chemically related variables (e.g., such as the initiation and rate of the reactions involved) and mechanically related variables (e.g., the surface friction coefficient and viscoelasticity of the polishing pad) in the CMP process are highly temperature dependent. Thus, variations in the surface temperature of the polishing pad can result in variations in removal rate, polishing uniformity, erosion, dishing, and residue. By more tightly controlling the temperature of the polishing pad surface during polishing, temperature variations can be reduced, and polishing performance, such as measured by intra-wafer non-uniformity or inter-wafer non-uniformity, can be improved.

[0042] In addition, during CMP, debris and slurry may accumulate on various components of the CMP equipment. If these polishing byproducts later break off the components, they may scratch or otherwise damage the substrate, resulting in increased polishing defects. Water jets have been used to clean various components of the CMP equipment system. However, large amounts of water are required to perform this task.

[0043] A technique that may address one or more of these issues is to use steam (i.e., gaseous H2O produced by boiling) to clean and / or preheat various components of the CMP equipment. For example, due to the latent heat of steam, less steam may be required to provide the same amount of energy as hot water. Additionally, steam may be sprayed at high velocities to clean and / or preheat components. Furthermore, steam is more effective than liquid water in dissolving or otherwise removing polishing byproducts.

[0044] Figure 1 2 is a plan view of a chemical mechanical polishing apparatus 2 for processing one or more substrates. The polishing apparatus 2 includes a polishing platform 4, which at least partially supports and accommodates a plurality of polishing stations 20. For example, the polishing apparatus may include four polishing stations 20a, 20b, 20c, and 20d. Each polishing station 20 is adapted to polish a substrate held in a carrier head 70. Figure 1 Not all components of each workstation are shown.

[0045] The polishing apparatus 2 also includes a plurality of carrier heads 70, each of which is configured to carry a substrate. The polishing apparatus 2 also includes a transfer station 6 for loading and unloading substrates from the carrier head. The transfer station 6 may include a plurality of loading covers 8 (e.g., two loading covers 8a, 8b), which are adapted to facilitate the transfer of substrates between the carrier head 70 and a factory interface (not shown) or other devices (not shown) by a transfer robot 9. The loading cover 8 generally facilitates the transfer between the robot 9 and each of the loading heads 70 by loading and unloading the loading heads 70.

[0046] The stations of the polishing apparatus 2, including the transfer station 6 and the polishing station 20, may be positioned at substantially equal angular intervals about the center of the platform 4. This is not required, but may provide a good footprint for the polishing apparatus.

[0047] For polishing operations, one carrier head 70 is positioned at each polishing station. Two additional carrier heads may be positioned in the loading and unloading station 6 to replace polished substrates with unpolished substrates while other substrates are being polished at the polishing station 20.

[0048] The carrier heads 70 are held by a support structure that allows each carrier head to move along a path that sequentially passes through the first polishing station 20a, the second polishing station 20b, the third polishing station 20c, and the fourth polishing station 20d. This allows each carrier head to be selectively positioned above the polishing station 20 and the loading cover 8.

[0049] In some embodiments, each carrier head 70 is coupled to a carriage 78, which is mounted to a support structure 72. By moving the carriage 78 along a support structure 72 (e.g., a track), the carrier heads 70 can be positioned over a selected polishing station 20 or loading hood 8. Alternatively, the carrier heads 70 can be suspended from a carousel, and rotation of the carousel moves all of the carrier heads simultaneously along a circular path.

[0050] Each polishing station 20 of the polishing apparatus 2 may include a port, for example, at the end of a slurry supply arm 39, to supply a polishing liquid 38 such as an abrasive slurry (see Figure 3A ) is distributed onto the polishing pad 30. Each polishing station 20 of the polishing apparatus 2 may further include a pad conditioner 93 to grind the polishing pad 30 to maintain the polishing pad 30 in a consistent grinding state.

[0051] Figure 3A and Figure 3B An example of a polishing station 20 of a chemical mechanical polishing system is shown. The polishing station 20 includes a rotatable disc-shaped platform 24 on which a polishing pad 30 is located. The platen 24 is operable to rotate about an axis 25 (see Figure 3BFor example, the motor 22 can rotate the drive shaft 28 to rotate the platen 24. The polishing pad 30 can be a dual-layer polishing pad having an outer polishing layer 34 and a softer backing layer 32.

[0052] Reference Figure 1 , Figure 3A and Figure 3B The polishing station 20 may include a supply port, for example at the end of a slurry supply arm 39 , to dispense a polishing liquid 38 , such as an abrasive slurry, onto the polishing pad 30 .

[0053] The polishing station 20 may include a pad conditioner 90 having a conditioner disk 92 (see FIG. 2 ) to maintain the surface roughness of the polishing pad 30. The conditioner disk 92 may be positioned in a conditioner head 93 at the end of an arm 94. The arm 94 and conditioner head 93 are supported by a base 96. The arm 94 may swing to sweep the conditioner head 93 and conditioner disk 92 laterally across the polishing pad 30. The cleaning cup 255 may be located adjacent to the platen 24, and the arm 94 may move the conditioner head 93 to said position.

[0054] The carrier head 70 is 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 drive shaft 74 so that the carrier head can rotate about an axis 71. Optionally, the carrier head 70 can be vibrated laterally, for example, on a slide on a carousel, by movement along a track, or by rotational vibration of the carousel itself.

[0055] The carrier head 70 may include an elastic membrane 80 having a substrate mounting surface in contact with the back side of the substrate 10 and a plurality of pressurizable chambers 82 that apply different pressures to different areas, such as different radial areas, on the substrate 10. The carrier head 70 may include a retaining ring 84 to hold the substrate. In some embodiments, the retaining ring 84 may include a lower plastic portion 86 that contacts the polishing pad and an upper portion 88 of a harder material (e.g., metal).

[0056] In operation, the platform rotates about the platform central axis 25, and the carrier head rotates about the carrier head central axis 71 (see Figure 3B arrow B) and lateral translation (see Figure 3B The arrow C) in FIG. 1 crosses the top surface of the polishing pad 30 .

[0057] Reference Figure 3A and Figure 3BAs the carrier head 70 sweeps across the polishing pad 30, any exposed surface of the carrier head 70 tends to be covered with slurry. For example, the slurry may adhere to the outer diameter surface or the inner diameter surface of the retaining ring 84. Generally, the slurry will tend to coagulate and / or dry out for any surface that is not kept in a wet state. As a result, particles may form on the carrier head 70. If these particles break off, they may scratch the substrate, resulting in polishing defects.

[0058] In addition, the slurry may cake on the carrier head 70, or the sodium hydroxide in the slurry may crystallize on one of the surfaces of the carrier head 70 and / or the substrate 10 and cause corrosion of the surface of the carrier head 70. The caked slurry is difficult to remove, and the crystallized sodium hydroxide is difficult to return to solution.

[0059] Similar problems may occur with the conditioner head 92 , for example, particulates may form on the conditioner head 92 , the slurry may agglomerate on the conditioner head 92 , or sodium hydroxide in the slurry may crystallize on one of the surfaces of the conditioner head 92 .

[0060] One solution is to clean the components (e.g., carrier head 70 and conditioner head 92) with a liquid water jet. However, using only a water jet can be difficult to clean the components and can require large amounts of water. Additionally, the components in contact with the polishing pad 30 (e.g., carrier head 70, substrate 10, and conditioner disk 92) can act as a heat sink that impedes the uniformity of the polishing pad temperature.

[0061] To solve these problems, Figure 2A As shown, the polishing apparatus 2 includes one or more carrier head vapor treatment assemblies 200. Each vapor treatment assembly 200 can be used to clean and / or preheat the carrier head 70 and substrate 10.

[0062] The steam handling assembly 200 may be part of the loading hood 8 , for example, part of the loading hood 8 a or the loading hood 8 b . Alternatively or additionally, the steam handling assembly 200 may be disposed at one or more inter-platen stations 9 located between adjacent polishing stations 20 .

[0063] The loading hood 8 includes a base 204 to hold the substrate 10 during the loading / unloading process. The loading hood 8 also includes a housing 206 that surrounds or substantially surrounds the base 204. A plurality of nozzles 225 are supported by the housing 206 or a separate support to deliver steam 245 to a carrier head and / or a substrate positioned in a cavity 208 defined by the housing 206. For example, the nozzles 225 may be positioned on one or more inner surfaces of the housing 206, such as the bottom plate 206a and / or the sidewall 206b and / or the ceiling of the cavity. The nozzles 225 may be oriented to direct the steam inwardly into the cavity 206. The steam 245 may be generated by using a steam generator 410 (e.g., a boiler such as a flash boiler or a conventional boiler). The exhaust port 235 may allow excess water, cleaning solution, and cleaning byproducts to pass through to prevent accumulation in the loading hood 8.

[0064] The actuator provides relative vertical movement between the housing 206 and the carrier head 70. For example, the shaft 210 can support the housing 206 and be vertically actuatable to raise and lower the housing 206. Alternatively, the carrier head 70 can move vertically. The base 205 can be on-axis with the shaft 210. The base 204 can be vertically movable relative to the housing 206.

[0065] In operation, the carrier head 70 can be positioned above the loading hood 8, and the housing 206 can be raised (or the carrier head 70 lowered) so that the carrier head 70 is partially located within the cavity 208. The substrate 10 can start on the pedestal 204 and be chucked onto the carrier head 70, and / or start on the carrier head 70 and be dechucked onto the pedestal 204.

[0066] Steam is directed through the nozzles 225 to clean and / or preheat one or more surfaces of the substrate 10 and / or the carrier head 70. For example, one or more of the nozzles may be positioned to direct steam onto an outer surface of the carrier head 70, an outer surface 84a of the retaining ring 84, and / or a bottom surface 84b of the retaining ring 84. One or more of the nozzles may be positioned to direct steam onto the front surface (i.e., the surface to be polished) of the substrate 10 held by the carrier head 70, or onto the bottom surface of the film 80 if no substrate 10 is supported on the carrier head 70. One or more nozzles may be positioned below the pedestal 204 to direct steam upward onto the front surface of the substrate 10 positioned on the pedestal 204. One or more nozzles may be positioned above the pedestal 204 to direct steam downward onto the back surface of the substrate 10 positioned on the pedestal 204. The carrier head 70 may be rotated within the loading hood 8 and / or moved vertically relative to the loading hood 8 to allow the nozzles 225 to treat different areas of the carrier head 70 and / or the substrate 10. Substrate 10 may be mounted on pedestal 205 to allow for vapor treatment of an inner surface of carrier head 70 (eg, a bottom surface of membrane 82 or an inner surface of retaining ring 84).

[0067] Steam is circulated from a steam source to the nozzle 225 through a supply line 230 that passes through the housing 206. The nozzle 225 may spray steam 245 to remove organic residues, byproducts, debris, and slurry particles that remain on the carrier head 70 and the substrate 10 after each polishing operation. The nozzle 225 may spray steam 245 to heat the substrate 10 and / or the carrier head 70.

[0068] The inter-platen station 9 may be similarly constructed and operated, but need not have a substrate support pedestal.

[0069] The vapor 245 delivered by the nozzles 225 can have adjustable temperature, pressure, and flow rate to vary the cleaning and preheating of the carrier head 70 and substrate 10. In some embodiments, the temperature, pressure, and / or flow rate can be adjusted independently for each nozzle or between groups of nozzles.

[0070] For example, when the steam 245 is generated (e.g., in the steam generator 410), the temperature of the steam 245 can be between 90° C. and 200° C. For example, due to heat losses in delivery, when the steam 245 is distributed through the nozzle 225, the temperature of the steam 245 can be between 90° C. and 150° C. In some embodiments, the steam is delivered by the nozzle 225 at a temperature of 70-100° C., such as 80-90° C. In some embodiments, the steam delivered by the nozzle is superheated, i.e., at a temperature above the boiling point.

[0071] When steam 245 is delivered through nozzle 225, the flow rate of steam 245 can be 1-1000cc / minute, depending on the heater power and pressure. In some embodiments, steam is mixed with other gases, for example, with normal atmosphere or with N2. Alternatively, the fluid delivered by nozzle 225 is substantially pure water. In some embodiments, steam 245 delivered by nozzle 225 is mixed with liquid water (e.g., atomized water). For example, liquid water and steam can be combined at a relative flow ratio (e.g., flow rate in sccm) of 1:1 to 1:10. However, if the amount of liquid water is low, for example, less than 5 weight percent (wt%), for example, less than 3 weight percent, for example, less than 1 weight percent, the steam will have excellent heat transfer properties. Therefore, in some embodiments, the steam is dry steam, that is, substantially free of water droplets.

[0072] To avoid thermal degradation of the membrane, water may be mixed with the steam 245 to reduce the temperature, for example to about 40-50° C. The temperature of the steam 245 may be reduced by mixing cooled water into the steam 245 or by mixing water at the same or substantially the same temperature into the steam 245 (because liquid water transfers less energy than gaseous water).

[0073] In some embodiments, a temperature sensor 214 can be mounted in or adjacent to the steam treatment assembly 200 to detect the temperature of the carrier head 70 and / or the substrate 10. A signal from the sensor 214 can be received by the controller 12 to monitor the temperature of the carrier head 70 and / or the substrate 10. The controller 12 can control the steam delivery by the assembly 100 based on the temperature measurement from the temperature sensor 214. For example, the controller can receive a target temperature value. If the controller 12 detects that the temperature measurement exceeds the target value, the controller 12 stops the steam flow. As another example, the controller 12 can reduce the steam delivery flow rate and / or reduce the steam temperature, for example, to prevent overheating of the components during cleaning and / or preheating.

[0074] In some embodiments, the controller 12 includes a timer. In this case, the controller 12 can be activated when steam delivery begins and can stop delivering steam when the timer expires. The timer can be set based on empirical testing to achieve the desired temperature of the carrier head 70 and substrate 10 during cleaning and / or preheating.

[0075] Figure 2BA conditioner steam disposal assembly 250 including a housing 255 is shown. The housing 255 can be formed as a "cup" to receive the conditioner disc 92 and the conditioner head 93. Steam is circulated to one or more nozzles 275 through a supply line 280 in the housing 255. The nozzles 275 can spray steam 295 to remove polishing byproducts, such as debris or slurry particles, that remain on the conditioner disc 92 and / or the conditioner head 93 after each conditioning operation. The nozzles 275 can be located in the housing 255, for example, on a bottom plate, side wall, or top plate inside the housing 255. One or more nozzles can be positioned to clean the bottom surface of the pad conditioner disc and / or the bottom surface, side wall, and / or top surface of the conditioner head 93. The steam 295 can be generated using a steam generator 410. The exhaust port 285 can allow excess water, cleaning solution, and cleaning byproducts to pass through to prevent accumulation in the housing 255.

[0076] Conditioner head 93 and conditioner disk 92 may be at least partially lowered into housing 255 to await steam disposal. When conditioner disk 92 is to resume operation, conditioner head 93 and conditioning disk 92 are lifted out of housing 255 and positioned over polishing pad 30 to condition polishing pad 30. When the conditioning operation is complete, conditioner head 93 and conditioning disk 92 are lifted off the polishing pad and swung back into housing cup 255 for removal of polishing byproducts from conditioner head 93 and conditioner disk 92. In some embodiments, housing 255 is vertically actuatable, e.g., mounted to vertical drive shaft 260.

[0077] The housing 255 is positioned to receive the pad conditioner disc 92 and the conditioner head 93. The conditioner disc 92 and the conditioner head 93 can rotate within the housing 255 and / or move vertically in the housing 255 to allow the nozzle 275 to steam treat various surfaces of the conditioner disc 92 and the conditioner head 93.

[0078] The steam 295 delivered by the nozzle 275 can have an adjustable temperature, pressure and / or flow rate. In some embodiments, the temperature, pressure and / or flow rate can be adjusted independently for each nozzle or between groups of nozzles. This allows for variation and therefore more efficient cleaning of the conditioner disk 92 or conditioner head 93.

[0079] For example, when the steam 295 is generated (e.g., in the steam generator 410), the temperature of the steam 295 can be between 90° C. and 200° C. For example, due to heat losses in delivery, when the steam 295 is distributed through the nozzle 275, the temperature of the steam 295 can be between 90° C. and 150° C. In some embodiments, the steam can be delivered by the nozzle 275 at a temperature of 70-100° C., such as 80-90° C. In some embodiments, the steam delivered by the nozzle is superheated, i.e., at a temperature above the boiling point.

[0080] When steam 295 is delivered through nozzle 275, the flow rate of steam 2945 can be 1-1000cc / minute. In some embodiments, steam is mixed with other gases, for example, with normal atmosphere or with N2. Alternatively, the fluid delivered by nozzle 275 is substantially pure water. In some embodiments, steam 295 delivered by nozzle 275 is mixed with liquid water (e.g., atomized water). For example, liquid water and steam can be combined at a relative flow ratio (e.g., flow rate in sccm) of 1:1 to 1:10. However, if the amount of liquid water is low, for example, less than 5 weight percent, for example, less than 3 weight percent, for example, less than 1 weight percent, the steam will have excellent heat transfer properties. Therefore, in some embodiments, the steam is dry steam, that is, does not include water droplets.

[0081] In some embodiments, a temperature sensor 264 can be mounted in or adjacent to the housing 255 to detect the temperature of the regulator head 93 and / or the regulator disk 92. The controller 12 can receive a signal from the temperature sensor 264 to monitor the temperature of the regulator head 93 or the regulator disk 92, for example, to detect the temperature of the pad regulator disk 92. The controller 12 can control the steam delivery by the assembly 250 based on the temperature measurement from the temperature sensor 264. For example, the controller can receive a target temperature value. If the controller 12 detects that the temperature measurement exceeds the target value, the controller 12 stops the steam flow. As another example, the controller 12 can reduce the steam delivery flow rate and / or reduce the steam temperature, for example, to prevent overheating of components during cleaning and / or preheating.

[0082] In some embodiments, the controller 12 uses a timer. In this case, the controller 12 can start the timer when the steam delivery begins, and stop the steam delivery when the timer expires. The timer can be set based on empirical testing to achieve the desired temperature of the regulator disk 92 during cleaning and / or preheating, for example, to prevent overheating.

[0083] Reference Figure 3A In some embodiments, the polishing station 20 includes a temperature sensor 64 to monitor the temperature in the polishing station or the temperature of a component of the polishing station or the temperature of a component in the polishing station, for example, the temperature of the polishing pad 30 and / or the temperature of the slurry 38 on the polishing pad. For example, the temperature sensor 64 can be an infrared (IR) sensor (e.g., an IR camera) positioned above the polishing pad 30 and configured to measure the temperature of the polishing pad 30 and / or the temperature of the slurry 38 on the polishing pad. Specifically, the temperature sensor 64 can be configured to measure the temperature at multiple points along the radius of the polishing pad 30 to generate a radial temperature profile. For example, the IR camera can have a field of view that spans the radius of the polishing pad 30.

[0084] In some embodiments, the temperature sensor is a contact sensor rather than a non-contact sensor. For example, the temperature sensor 64 can be a thermocouple or an IR thermometer positioned on or in the platen 24. In addition, the temperature sensor 64 can be in direct contact with the polishing pad.

[0085] In some embodiments, multiple temperature sensors may be spaced at different radial locations throughout the polishing pad 30 to provide temperature at multiple points along the radius of the polishing pad 30. This technique may be used in lieu of or in addition to an IR camera.

[0086] Although the temperature sensor 64 is Figure 3A 30, but the temperature sensor 64 may be positioned within the carrier head 70 to measure the temperature of the substrate 10. The temperature sensor 64 may be in direct contact (i.e., a contact sensor) with the semiconductor wafer of the substrate 10. In some embodiments, multiple temperature sensors are included in the polishing station 22, for example, to measure the temperature of different components of the polishing station or the temperature of different components in the polishing station.

[0087] The polishing system 20 also includes a temperature control system 100 to control the temperature of the polishing pad 30 and / or the temperature of the slurry 38 on the polishing pad. The temperature control system 100 may include a cooling system 102 and / or a heating system 104. At least one of the cooling system 102 and the heating system 104, and in some embodiments both the cooling system 102 and the heating system 104, controls the temperature of the polishing pad 30 by delivering a temperature-controlled medium (e.g., liquid, vapor, or spray) to the polishing surface 36 of the polishing pad 30 (or to the polishing liquid already present on the polishing pad).

[0088] For the cooling system 102, the cooling medium can be a gas (e.g., air) or a liquid (e.g., water). The medium can be at room temperature or cooled to below room temperature, for example, at 5-15°C. In some embodiments, the cooling system 102 uses a spray of air and liquid, for example, an atomized spray of a liquid (e.g., water). Specifically, the cooling system can have a nozzle that produces an atomized spray of water, and the atomized spray of water is cooled below room temperature. In some embodiments, a solid material can be mixed with the gas and / or liquid. The solid material can be a cooled material (e.g., ice) or a material that absorbs heat when dissolved in water (e.g., by a chemical reaction).

[0089] The cooling medium may be delivered by flowing through one or more apertures (eg, holes or slots) in the coolant delivery arm, optionally formed in the nozzle. The apertures may be provided by a manifold connected to a coolant source.

[0090] like Figure 3A and Figure 3BAs shown, the example cooling system 102 includes an arm 110 that extends over the platen 24 and the polishing pad 30 from the edge of the polishing pad to or at least close to (e.g., within 5% of the total radius of the polishing pad) the center of the polishing pad 30. The arm 110 can be supported by a base 112, and the base 112 can be supported on the same frame 40 as the platen 24. The base 112 can include one or more actuators, such as linear actuators to raise or lower the arm 110, and / or rotary actuators to swing the arm 110 laterally over the platen 24. The arm 110 is positioned to avoid collision with other hardware components, such as the polishing head 70, the pad conditioning disk 92, and the slurry dispensing arm 39.

[0091] The example cooling system 102 includes a plurality of nozzles 120 suspended from an arm 110. Each nozzle 120 is configured to spray a liquid coolant medium (eg, water) onto the polishing pad 30. The arm 110 may be supported by a base 112 such that the nozzles 120 are separated from the polishing pad 30 by a gap 126.

[0092] Each nozzle 120 can be configured to direct atomized water in a spray 122 toward the polishing pad 30. The cooling system 102 can include a source 130 of a liquid coolant medium and a source 132 of a gas (see Figure 3B ). Liquid from source 130 and gas from source 132 may be mixed in mixing chamber 134 (eg, on or in arm 110) (see Figure 3A ), and then directed through nozzle 120 to form spray 122.

[0093] In some embodiments, process parameters, such as flow rate, pressure, temperature, and / or the ratio of liquid to gas, can be controlled independently for each nozzle. For example, the coolant for each nozzle 120 can flow through an independently controllable cooler to independently control the temperature of the spray. As another example, a separate pair of pumps, one for gas and one for liquid, can be connected to each nozzle so that the flow rate, pressure, and ratio of gas to liquid can be controlled individually for each nozzle.

[0094] Various nozzles can spray onto different radial zones 124 on the polishing pad 30. Adjacent radial zones 124 can overlap. In some embodiments, the nozzles 120 produce a spray that impinges on the polishing pad 30 along an elongated region 128. For example, the nozzles can be configured to produce a spray in a generally planar triangular volume.

[0095] One or more of the elongated regions 128 (eg, all of the elongated regions 128) may have a longitudinal axis (see region 128a) that is parallel to a radius extending through the region 128. Alternatively, the nozzle 120 produces a cone-shaped spray.

[0096] although Figure 1 The sprays themselves are shown overlapping, but the nozzles 120 may be oriented so that the elongated regions do not overlap. For example, at least some of the nozzles 120 (eg, all of the nozzles 120) may be oriented so that the elongated regions 128 are at an oblique angle relative to a radius passing through the elongated regions (see region 128b).

[0097] At least some of the nozzles 120 can be oriented so that the central axis of the spray from the nozzle (see arrow A) is at an oblique angle relative to the polishing surface 36. Specifically, the spray 122 can be directed from the nozzles 120 to have a horizontal component in a direction opposite to the direction of movement of the polishing pad 30 in the impact area caused by the rotation of the platen 24 (see arrow A).

[0098] although Figure 3A and Figure 3B The nozzles 120 are shown as being spaced at uniform intervals, but this is not required. The nozzles 120 may be unevenly distributed radially, angularly, or both. For example, the nozzles 120 may be more densely clustered along the radial direction toward the edge of the polishing pad 30. In addition, although Figure 3A and Figure 3B Nine nozzles are shown, but there may be a greater or lesser number of nozzles, for example, three to twenty nozzles.

[0099] For the heating system 104, the heating medium can be a gas (e.g., steam (e.g., from the steam generator 410) or heated air) or a liquid (e.g., heated water) or a combination of gas and liquid. The medium is above room temperature, for example, at 40-120°C, for example, at 90-110°C. The medium can be water, such as substantially pure deionized water, or water containing additives or chemicals. In some embodiments, the heating system 104 uses steam spray. The steam can contain additives or chemicals.

[0100] The heating medium may be delivered by flowing through apertures (eg holes or slots) in the heating delivery arm (eg provided by one or more nozzles). The apertures may be provided by a manifold connected to a source of the heating medium.

[0101] The example heating system 104 includes an arm 140 that extends over the platen 24 and polishing pad 30 from the edge of the polishing pad to at least close to (e.g., within 5% of the total radius of the polishing pad) the center of the polishing pad 30. The arm 140 can be supported by a base 142, and the base 142 can be supported on the same frame 40 as the platen 24. The base 142 can include one or more actuators, such as a linear actuator to raise or lower the arm 140, and / or a rotary actuator to swing the arm 140 laterally over the platen 24. The arm 140 is positioned to avoid collision with other hardware components, such as the polishing head 70, the pad conditioning disk 92, and the slurry dispensing arm 39.

[0102] Along the rotation direction of the platen 24, the arm 140 of the heating system 104 may be positioned between the arm 110 of the cooling system 110 and the carrier head 70. Along the rotation direction of the platen 24, the arm 140 of the heating system 104 may be positioned between the arm 110 of the cooling system 110 and the slurry delivery arm 39. For example, the arm 110 of the cooling system 110, the arm 140 of the heating system 104, the slurry delivery arm 39, and the carrier head 70 may be sequentially arranged along the rotation direction of the platen 24.

[0103] A plurality of openings 144 are formed in the bottom surface of the arm 140. Each opening 144 is configured to direct a gas or vapor (e.g., steam) onto the polishing pad 30. The arm 140 can be supported by the base 142 so that the opening 144 is separated from the polishing pad 30 by a gap. The gap can be 0.5 mm to 5 mm. Specifically, the gap can be selected so that the heat of the heating fluid is not significantly dissipated before the fluid reaches the polishing pad. For example, the gap can be selected so that the steam emitted from the opening does not condense before reaching the polishing pad.

[0104] The heating system 104 can include a steam source 148 (eg, a steam generator 410 ) that can be connected to the arm 140 via a conduit. Each opening 144 can be configured to direct steam toward the polishing pad 30 .

[0105] In some embodiments, process parameters such as flow rate, pressure, temperature and / or liquid to gas mixing ratio can be independently controlled for each nozzle. For example, the fluid for each opening 144 can flow through an independently controllable heater to independently control the temperature of the heated fluid, such as the temperature of the steam.

[0106] The various openings 144 can direct the steam onto different radial zones on the polishing pad 30. Adjacent radial zones can overlap. Optionally, some of the openings 144 can be oriented so that the central axis of the spray from the openings is at an oblique angle relative to the polishing surface 36. The steam can be directed from one or more of the openings 144 to have a horizontal component in a direction opposite to the direction of movement of the polishing pad 30 in the impact area caused by the rotation of the platen 24.

[0107] although Figure 3B The openings 144 are shown as being spaced at uniform intervals, but this is not required. The nozzles 120 may be unevenly distributed radially, angularly, or both. For example, the openings 144 may be more densely clustered toward the center of the polishing pad 30. As another example, the openings 144 may be more densely clustered at a radius corresponding to a radius at which the polishing liquid 39 is delivered to the polishing pad 30 by the slurry delivery arm 39. In addition, although Figure 3BNine openings are shown, but there may be a greater or lesser number of openings.

[0108] The polishing system 20 may also include a high pressure rinse system 106. The high pressure rinse system 106 includes a plurality of nozzles 154 (e.g., three to twenty nozzles) that direct a cleaning fluid (e.g., water) at a high intensity onto the polishing pad 30 to clean the pad 30 and remove spent slurry, polishing debris, etc.

[0109] like Figure 3B As shown, the example flushing system 106 includes an arm 150 that extends over the platen 24 and polishing pad 30 from the edge of the polishing pad to at least close to (e.g., within 5% of the total radius of the polishing pad) the center of the polishing pad 30. The arm 150 can be supported by a base 152, and the base 152 can be supported on the same frame 40 as the platen 24. The base 152 can include one or more actuators, such as a linear actuator to raise or lower the arm 150, and / or a rotary actuator to swing the arm 150 laterally on the platen 24. The arm 150 is positioned to avoid collision with other hardware components, such as the polishing head 70, the pad conditioning disk 92, and the slurry dispensing arm 39.

[0110] Along the direction of rotation of the platen 24, the arm 150 of the flushing system 106 may be between the arm 110 of the cooling system 110 and the arm 140 of the heating system 140. For example, the arm 110 of the cooling system 110, the arm 150 of the flushing system 106, the arm 140 of the heating system 104, the slurry delivery arm 39, and the carrier head 70 may be sequentially disposed along the direction of rotation of the platen 24. Alternatively, along the direction of rotation of the platen 24, the arm 140 of the cooling system 104 may be between the arm 150 of the flushing system 106 and the arm 140 of the heating system 140. For example, the arm 150 of the flushing system 106, the arm 110 of the cooling system 110, the arm 140 of the heating system 104, the slurry delivery arm 39, and the carrier head 70 may be sequentially disposed along the direction of rotation of the platen 24.

[0111] although Figure 3B The nozzles 154 are shown spaced evenly apart, but this is not required. Figure 3A and Figure 3B Nine nozzles are shown, but there may be a greater or lesser number of nozzles, such as three to twenty nozzles.

[0112] The polishing system 2 may also include a controller 12 to control the operation of various components (e.g., the temperature control system 100). The controller 12 is configured to receive temperature measurements for each radial region of the polishing pad from the temperature sensor 64. The controller 12 may compare the measured temperature profile with the desired temperature profile and generate a feedback signal to a control mechanism (e.g., an actuator, power supply, pump, valve, etc.) for each nozzle or opening. The controller 12 calculates the feedback signal (e.g., based on an internal feedback algorithm) to cause the control mechanism to adjust the amount of cooling or heating so that the polishing pad and / or slurry reaches (or at least moves closer to) the desired temperature profile.

[0113] In some embodiments, the polishing system 20 includes a wiper blade or body 170 to evenly distribute the polishing liquid 38 across the polishing pad 30. The wiper blade 170 can be positioned between the slurry delivery arm 39 and the carrier head 70 along the rotation direction of the platen 24.

[0114] Figure 3B A separate arm is shown for each subsystem (e.g., heating system 102, cooling system 104, and flushing system 106), and the various subsystems can be contained in a single assembly supported by a common arm. For example, the assembly can include a cooling module, a flushing module, a heating module, a slurry delivery module, and optionally a scraper module. Each module can include a body (e.g., an arcuate body) that can be fixed to a common mounting plate, and the common mounting plate can be fixed to the end of the arm so that the assembly is positioned above the polishing pad 30. Various fluid delivery components (e.g., pipes, channels, etc.) can extend inside each body. In some embodiments, the module can be disassembled separately from the mounting plate. Each module can have similar components to perform the functions of the arms of the above-mentioned associated systems.

[0115] Reference Figure 1 , Figure 2A , Figure 2B , Figure 3A and Figure 3B, controller 12 can monitor the temperature measurements received by sensor 64, sensor 214, and sensor 264, and control temperature control system 100 and the amount of steam delivered to vapor handling assembly 200 and vapor handling assembly 250. Controller 12 can continuously monitor the temperature measurements and control the temperature in a feedback loop to regulate the temperature of polishing pad 30, carrier head 70, and conditioning plate 92. For example, controller 12 can receive the temperature of polishing pad 30 from sensor 64, and control the delivery of steam to carrier head 70 and / or conditioner head 92 to raise the temperature of carrier head 70 and / or conditioner head 92 to match the temperature of polishing pad 30. Reducing the temperature differential can help prevent carrier head 70 and / or conditioner head 92 from acting as a heat sink on the relatively higher temperature polishing pad 30, and can improve within-wafer uniformity.

[0116] In some embodiments, controller 12 stores desired temperatures for polishing pad 30, carrier head 70, and conditioner disk 92. Controller 12 can monitor temperature measurements from sensor 64, sensor 214, and sensor 264, and control temperature control system 100 and vapor handling assembly 200 and / or vapor handling assembly 250 to bring the temperatures of polishing pad 30, carrier head 70, and / or conditioner disk 92 to the desired temperatures. By bringing the temperatures to the desired temperatures, controller 12 can improve intra-wafer uniformity and inter-wafer uniformity.

[0117] Alternatively, the controller 12 may raise the temperature of the carrier head 70 and / or the conditioner head 92 to slightly above the temperature of the polishing pad 30 to allow the carrier head 70 and / or the conditioner head 92 to cool to the same or substantially the same temperature as the polishing head 30 when moved from their respective cleaning and preheating stations to the polishing pad 30.

[0118] Several embodiments of the present invention have been described. However, it should be understood that various modifications can be made without departing from the spirit and scope of the present invention. Therefore, other embodiments are within the scope of the following claims.

Claims

1. A chemical mechanical polishing system, comprising: a pressure plate supporting a polishing pad; boiler; a component of the chemical mechanical polishing system, the component being movable between a first position spaced apart from the polishing pad and a second position in contact with the polishing pad; a plurality of nozzles that direct steam from the boiler onto the component of the polishing system when the component of the polishing system is in the first position; an actuator that moves the member from the first position to the second position in contact with the polishing pad; as well as A controller configured to causing the treatment station to direct the steam onto the component to clean the component, and The actuator is caused to move the component being cleaned from the treatment station into contact with the polishing pad.

2. The system of claim 1, wherein the component comprises a carrier head.

3. The system of claim 2, comprising a substrate transfer station, and wherein the first position is in the substrate transfer station.

4. The system of claim 2, comprising a platen station, and wherein the first position is in the platen station.

5. The system of claim 1, wherein the component comprises a regulator disk or a regulator head.

6. The system of claim 5, comprising a conditioner disc cleaning cup, and wherein the first position is in the conditioner disc cleaning cup.

7. The system of claim 1, comprising a motor and a drive shaft to rotate the component, and wherein the controller is configured to cause the motor and the drive shaft to rotate the component when steam is directed onto the component.

8. The system of claim 1, comprising a motor and a support shaft to vertically displace the component, and wherein the controller is configured to cause the motor and the support shaft to vertically displace the component when steam is directed onto the component.

9. The system of claim 1, wherein the controller is configured to set a timer and to stop directing the steam when the timer expires.

10. The system of claim 1, wherein the controller is configured to control the boiler so that the steam has a temperature of 70-100°C.

11. The system of claim 10, wherein the controller is configured to control the boiler so that the steam has a temperature of 80-100°C.

12. The system of claim 1, wherein the boiler is configured to provide dry steam.

13. The system of claim 1, wherein the boiler is configured to provide a gas consisting of steam.

14. The system of claim 1, wherein the boiler is configured to provide a gas comprising a mixture of steam and atmospheric air.

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