Use of steam for preheating or cleaning CMP components
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- APPLIED MATERIALS INC
- Filing Date
- 2025-02-25
- Publication Date
- 2026-08-03
Smart Images
Figure 0007899379000001 
Figure 0007899379000002 
Figure 0007899379000003
Abstract
Description
Technical Field
[0001] The present disclosure relates to chemical mechanical polishing (CMP), and more particularly to the use of steam for cleaning or preheating during CMP.
Background Art
[0002] Integrated circuits are typically formed on a substrate by sequentially depositing conductive, semiconductive, or insulating layers on a semiconductor wafer. In various manufacturing processes, planarization of the layers on the substrate is required. For example, one manufacturing step involves depositing a fill layer on a non-planar surface and planarizing the fill layer. In certain applications, the fill 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 trenches and holes within the insulating layer. After planarization, vias, plugs, and lines that provide conductive paths between thin film circuits on the substrate are formed by the portions of metal remaining in the trenches and holes of the patterned layer. As another example, a dielectric layer can be deposited on a patterned conductive layer and then planarized to enable subsequent photolithography steps.
[0003] Chemical mechanical polishing (CMP) is an accepted method of planarization. This planarization method typically requires that the substrate be attached to a carrier head. The exposed surface of the substrate is typically positioned against a rotating polishing pad. The carrier head applies a controllable load to the substrate and presses it against the polishing pad. Typically, a polishing slurry containing abrasive particles is supplied to the surface of the polishing pad.
Summary of the Invention
[0004] In one embodiment, a method for controlling the temperature of a chemical mechanical polishing system includes introducing a water vapor-containing gas from an orifice into a component within the polishing system to raise the temperature of the component to a raised temperature while the component is separated from the polishing pad of the polishing system, and moving the component to contact the polishing pad before the component returns to ambient temperature.
[0005] The embodiment may include one or more of the following features:
[0006] The temperature of the component may be measured while water vapor is being introduced into the component, and the water vapor is stopped when the component reaches the target temperature. The temperature of the polishing pad may be measured, and the target temperature may be based on that measured temperature.
[0007] A timer may be set, and the steam may be stopped when the timer expires.
[0008] The temperature of the component can be approximately equal to the temperature of the polishing pad when the component comes into contact with the polishing pad. The temperature rise may be higher than the temperature of the polishing pad.
[0009] The gas may have a temperature of 70-100°C. The water vapor may be dry steam. The gas may consist of water vapor.
[0010] To guide steam to the components in the processing station, the components may be positioned with a gap between them and the polishing pads. The components may be rotated within the processing station as steam is guided to them. The components may also move vertically within the processing station as steam is guided to them.
[0011] The components may include a carrier head or a substrate to be polished. Steam may be introduced to the components at a substrate transfer station. Steam may be introduced to the components at a platen-to-platen station.
[0012] The components may include a regulator disc or a regulator head. Steam may be introduced to the components through a cleaning cup on the regulator disc.
[0013] In another embodiment, the chemical mechanical polishing system includes a platen for supporting a polishing pad, a boiler, a processing station spaced apart from the polishing pad and having multiple nozzles for directing steam from the boiler into a main body located within the processing station, actuators for moving components from the processing station to contact the polishing pad, and a controller causing the processing station to direct steam to the components to raise their temperature to a high temperature, and causing the actuators to move the components from the processing station to contact the polishing pad before the components return to ambient temperature.
[0014] The embodiment may include one or more of the following features:
[0015] The components may include a carrier head or a substrate. The components may include a regulator head or a regulator disk.
[0016] In another embodiment, a cleaning method for a chemical mechanical polishing system includes introducing a gas containing water vapor from an orifice into the components within the polishing system to clean the components while the components are spaced apart from the polishing pads of the polishing system, and moving the components so that they come into contact with the polishing pads.
[0017] The embodiment may include one or more of the following features:
[0018] A timer may be set, and the steam may be stopped when the timer expires.
[0019] The gas may have a temperature of 70-100°C. The gas may have a temperature of 80-100°C. The water vapor may include dry water vapor. The gas may consist of water vapor. The gas may include a mixture of water vapor and the atmosphere.
[0020] The components may be placed within a processing station and may be positioned at a distance from the polishing pad to guide steam to the components within the processing station. The components may be rotated within the processing station as steam is guided to them. The components may be moved vertically within the processing station as steam is guided to them.
[0021] The components may include a carrier head or a substrate to be polished. Steam may be introduced to the components at a substrate transfer station. Steam may be introduced to the components at a platen-to-platen station.
[0022] The components may include a regulator disc or a regulator head. Steam may be introduced to the components through a cleaning cup on the regulator disc.
[0023] Cleaning the components may include removing solidified slurry. Cleaning the components may include removing solidified abrasive debris.
[0024] In one embodiment, a chemical mechanical polishing system includes a platen for supporting a polishing pad, a boiler, a processing station spaced apart from the polishing pad and having a plurality of nozzles for directing steam from the boiler into a main body located within the processing station, an actuator for moving a component from the processing station to contact the polishing pad, and a controller for causing the processing station to direct steam to the component to raise its temperature to a high temperature, and for causing the actuator to move the component from the processing station to contact the polishing pad.
[0025] The embodiment may include one or more of the following features:
[0026] The components may include a carrier head or a substrate to be polished.
[0027] The component may include an adjuster disk or an adjuster head.
[0028] Potential advantages may include, but are not limited to, one or more of the following.
[0029] Water vapor, i.e., gaseous H2O produced by boiling, can be produced in sufficient quantities with low levels of contaminants. In addition, a water vapor generator can produce water vapor that is substantially pure gas, e.g., water vapor having little or no suspended liquid therein. Such water vapor, also known as dry steam, can provide a gaseous form of H2O with higher energy transfer and lower liquid content than other water vapor alternatives such as flash steam.
[0030] Various components of the CMP apparatus can be cleaned quickly and efficiently. Water vapor can be more effective than liquid water in dissolving or otherwise removing polishing by-products, dry slurry, debris, etc. from surfaces within the polishing system. Thereby, defects on the substrate can be reduced.
[0031] Various components of the CMP apparatus can be preheated. Variations in temperature across the entire polishing pad and thus across the entire substrate can be reduced, thereby reducing within-wafer non-uniformity (WIWNU). Variations in temperature over a polishing operation can be reduced. Thereby, the predictability of polishing during the CMP process can be improved. Variations in temperature from one polishing operation to another can be reduced. Thereby, the uniformity between wafers can be improved.
[0032] Details of one or more embodiments are described in the accompanying drawings and the following description. Other aspects, features, and advantages will become apparent from these descriptions and drawings and from the claims.
Brief Description of the Drawings
[0033] [Figure 1] This is a schematic plan view of one embodiment of a polishing apparatus. [Figure 2A] This is a schematic cross-sectional view of an exemplary carrier head steam treatment assembly. [Figure 2B] This is a schematic cross-sectional view of an exemplary adjustment head steam treatment assembly. [Figure 3A] This is a schematic cross-sectional view of one embodiment of a polishing station of a polishing apparatus. [Figure 3B] This is a schematic top view of a polishing station in one embodiment of a chemical mechanical polishing apparatus. [Modes for carrying out the invention]
[0034] Chemical mechanical polishing operates through a combination of mechanical wear and chemical etching at the interface between the substrate, the polishing solution, and the polishing pad. During the polishing process, a considerable amount of heat is generated by friction between the substrate surface and the polishing pad. In addition, some processes include an in-situ pad conditioning step, in which a conditioning disc, for example, a disc coated with polishing diamond particles, is pressed against the rotating polishing pad to condition and texture the surface of the polishing pad. Heat can also be generated by the wear during the conditioning process. For example, in a typical 1-minute copper CMP process with a nominal downforce pressure of 2 psi and a removal rate of 8000 Å / min, the surface temperature of the polyurethane polishing pad can rise by approximately 30 degrees Celsius.
[0035] On the other hand, if the polishing pad was heated by a previous polishing operation, when a new substrate is first lowered and comes into contact with the polishing pad, it will be at a lower temperature and therefore can act as a heat sink. Similarly, the slurry dispensed onto the polishing pad can act as a heat sink. Overall, these effects result in spatial and temporal variations in the temperature of the polishing pad.
[0036] Both chemical variables (e.g., the initiation and rate of the reactions involved) and mechanical variables (e.g., the surface friction coefficient and viscoelasticity of the polishing pad) in the CMP process are strongly temperature-dependent. As a result, fluctuations in the surface temperature of the polishing pad can lead to changes in removal rate, polishing uniformity, erosion, dishing, and residue. By more precisely controlling the surface temperature of the polishing pad during polishing, temperature fluctuations can be reduced, and polishing performance, such as non-uniformity within or between wafers, can be improved.
[0037] Furthermore, debris and slurry can accumulate on various components of the CMP equipment during CMP. If these polishing by-products later detach from the components, they can scratch or even damage the substrate, potentially increasing polishing defects. Water jets have been used to clean various components of the CMP equipment system. However, this requires a large amount of water.
[0038] A technique that can address one or more of these problems is to clean and / or preheat the various components of the CMP equipment using steam, i.e., gaseous H2O produced by boiling. For example, due to the latent heat of steam, less steam may be needed to impart the same amount of energy as hot water. In addition, steam can be sprayed at high speed to clean and / or preheat the components. Furthermore, steam may be more effective than liquid water in dissolving or otherwise removing polishing byproducts.
[0039] Figure 1 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 that at least partially supports and houses 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 configured to polish a substrate held in a carrier head 70. Not all components of each station are shown in Figure 1.
[0040] The polishing apparatus 2 also includes a number of carrier heads 70, each carrier head configured to transport substrates. The polishing apparatus 2 also includes a transfer station 6 for loading and unloading substrates from the carrier heads. The transfer station 6 may include a number of load cups 8, for example, two load cups 8a, 8b, which are configured to facilitate the transfer of substrates between the carrier heads 70 and a factory interface (not shown) or other devices (not shown) by a transfer robot 9. The load cups 8 generally facilitate the transfer between the robot 9 and each of the carrier heads 70 by loading and unloading the carrier heads 70.
[0041] The stations of the polishing apparatus 2, including the transfer station 6 and the polishing station 20, may be arranged at substantially equal angular intervals around the center of the platform 4. While not strictly necessary, this can provide the polishing apparatus with a good footprint.
[0042] In the polishing operation, one carrier head 70 is placed at each polishing station. Two additional carrier heads can be placed in the load and unload station 6 to replace unpolished boards with polished boards while other boards are being polished at the polishing station 20.
[0043] The carrier head 70 is held by a support structure that allows each carrier head to move along a path that passes through the first polishing station 20a, the second polishing station 20b, the third polishing station 20c, and the fourth polishing station 20d in that order. This allows each carrier head to be selectively positioned on the polishing station 20 and the load cup 8.
[0044] In some embodiments, each carrier head 70 is coupled to a carriage 78 attached to a support structure 72. By moving the carriage 78 along the support structure 72, for example, a track, the carrier heads 70 can be positioned on a selected polishing station 20 or load cup 8. Alternatively, the carrier heads 70 may be suspended from a carousel, and the rotation of the carousel moves all the carrier heads simultaneously along a circular path.
[0045] Each polishing station 20 of the polishing apparatus 2 may include a port, for example, at the end of a slurry supply arm 39, for dispensing a polishing fluid 38 (see Figure 3A), such as a polishing slurry, onto the polishing pad 30. Each polishing station 20 of the polishing apparatus 2 may also include a pad adjuster 93 for wearing down the polishing pad 30 and maintaining the polishing pad 30 in a consistent polished state.
[0046] Figures 3A and 3B show an embodiment of a polishing station 20 of a chemical mechanical polishing system. The polishing station 20 includes a rotatable disc-shaped platen 24, on which the polishing pad 30 rests. The platen 24 is operable to rotate around an axis 25 (see arrow A in Figure 3B). For example, a motor 22 can rotate the platen 24 by turning a drive shaft 28. The polishing pad 30 may be a two-layer polishing pad having an outer polishing layer 34 and a softer backing layer 32.
[0047] Referring to Figures 1, 3A, and 3B, the polishing station 20 may include a supply port, for example, at the end of a slurry supply arm 39, for dispensing a polishing fluid 38, such as a polishing slurry, onto the polishing pad 30.
[0048] The polishing station 20 may include a pad adjuster 90 having an adjuster disc 92 (see Figure 2B) to maintain the surface roughness of the polishing pad 30. The adjuster disc 92 may be located in an adjuster head 93 at the end of an arm 94. The arm 94 and the adjuster head 93 are supported by a base 96. The arm 94 may swing to sweep the adjuster head 93 and the adjuster disc 92 across the polishing pad 30. The cleaning cup 255 may be positioned adjacent to the platen 24 in a position where the arm 94 can move the adjuster head 93.
[0049] The carrier head 70 is operable to hold the substrate 10 relative to the polishing pad 30. The carrier head 70 is suspended from a support structure 72 (e.g., a carousel or track) and connected to a carrier head rotating motor 76 by a drive shaft 74, so that the carrier head 70 can rotate around an axis 71. Optionally, the carrier head 70 can vibrate laterally, for example on a slider on a carousel, by movement along a track, or by rotational vibration of the carousel itself.
[0050] The carrier head 70 may include a flexible film 80 having a substrate mounting surface that contacts the back side of the substrate 10, and a plurality of pressurizable chambers 82 for applying different pressures to various zones on the substrate 10 (e.g., various radial zones). The carrier head 70 may include a retaining ring 84 for holding 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 made of a harder material, such as metal.
[0051] During operation, the platen rotates around its central axis 25, the carrier head rotates around its central axis 71 (see arrow B in Figure 3B), and is translated laterally (see arrow C in Figure 3B) across the upper surface of the polishing pad 30.
[0052] Referring to Figures 3A and 3B, as the carrier head 70 sweeps across the polishing pad 30, any exposed surface of the carrier head 70 tends to become covered with slurry. For example, slurry may adhere to the outer or inner diameter surface of the retaining ring 84. Generally, for surfaces that are not kept moist, the slurry tends to solidify and / or dry out. As a result, particles may form on the carrier head 70. When these particles detach, they can scratch the substrate, causing polishing defects.
[0053] Furthermore, the slurry may solidify on the carrier head 70, or the sodium hydroxide in the slurry may crystallize on the surface of either the carrier head 70 or / or the substrate 10, corroding the surface of the carrier head 70. Solidified slurry is difficult to remove, and crystallized sodium hydroxide is difficult to return to solution.
[0054] Similar problems can occur at the regulator head 92, for example, particles may form on the regulator head 92, the slurry may solidify on the regulator head 92, or the sodium hydroxide in the slurry may crystallize on one of the surfaces of the regulator head 92.
[0055] One solution is to clean the components, such as the carrier head 70 and the regulator head 92, with a liquid water jet. However, cleaning the components with a water jet alone may be difficult and may require a considerable amount of water. Furthermore, components that come into contact with the polishing pad 30, such as the carrier head 70, the substrate 10, and the regulator disc 92, may act as heat sinks that hinder the uniformity of the polishing pad temperature.
[0056] To address these issues, the polishing apparatus 2 includes one or more carrier head steam treatment assemblies 200, as shown in Figure 2A. Each steam treatment assembly 200 may be used for cleaning and / or preheating the carrier head 70 and the substrate 10.
[0057] The steam treatment assembly 200 may be a portion of the load cup 8, for example, a portion of load cup 8a or 8b. Alternatively or additionally, the steam treatment assembly 200 may be provided in one or more inter-platen stations 9 located between adjacent polishing stations 20.
[0058] The load cup 8 includes a pedestal 204 for holding the substrate 10 during the load / unload process. The load cup 8 also includes a housing 206 that surrounds or substantially surrounds the pedestal 204. Multiple nozzles 225 are supported by the housing 206 or a separate support to supply steam 245 to a carrier head and / or substrate located within a cavity 208 defined by the housing 206. For example, the nozzles 225 may be located on one or more inner surfaces of the housing 206, for example, the floor 206a and / or the side walls 206b and / or the ceiling of the cavity. The nozzles 225 may be directed to guide steam inward into the cavity 206. The steam 245 can be generated by using a steam generator 410, for example, a boiler such as a flash boiler or a conventional boiler. A drain pipe 235 may pass excess water, cleaning solution, and cleaning byproducts to prevent accumulation in the load cup 8.
[0059] The actuator provides relative vertical motion between the housing 206 and the carrier head 70. For example, the shaft 210 may support the housing 206 and be actuated vertically to raise and lower the housing 206. Alternatively, the carrier head 70 can move vertically. The pedestal 204 may be coaxial with the shaft 210. The pedestal 204 may be movable vertically relative to the housing 206.
[0060] In operation, the carrier head 70 may be positioned on the load cup 8, and the housing 206 rises (or lowers) so that the carrier head 70 is partially inside the cavity 208. The substrate 10 may start on the pedestal 204 and chuck onto the carrier head 70, and / or start on the carrier head 70 and dechuck onto the pedestal 204.
[0061] Steam is introduced through the nozzle 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 nozzles can be positioned to direct steam to the outer surface of the carrier head 70, the outer surface 84a of the retaining ring 84, and / or the lower surface 84b of the retaining ring 84. One or more nozzles can be positioned to direct steam to the front surface of the substrate 10 held by the carrier head 70, i.e., the surface to be polished, or to the underside of the film 80 if the substrate 10 is not supported on the carrier head 70. One or more nozzles can be positioned below the pedestal 204 to direct steam upward to the front surface of the substrate 10 placed on the pedestal 204. One or more nozzles can be positioned above the pedestal 204 to direct steam downward to the back surface of the substrate 10 placed on the pedestal 204. The carrier head 70 can rotate within the load cup 8 and / or move perpendicular to the load cup 8 so that the nozzle 225 can process various areas of the carrier head 70 and / or the substrate 10. The substrate 10 can be placed on the pedestal 204 so that the inner surface of the carrier head 70, for example, the underside of the film 80 or the inner surface of the retaining ring 84, can be treated with steam.
[0062] Steam is circulated from the steam source through the supply line 230 and through the housing 206 to the nozzle 225. The nozzle 225 can spray steam 245 to remove organic residues, by-products, debris, and slurry particles remaining on the carrier head 70 and substrate 10 after each polishing operation. The nozzle 225 can also spray steam 245 to heat the substrate 10 and / or the carrier head 70.
[0063] The platen-to-platen station 9 can be constructed and operated in a similar manner, but it is not necessarily required to have a board support pedestal.
[0064] The steam 245 supplied by the nozzle 225 may have adjustable temperature, pressure, and flow rate to vary the cleaning and preheating of the carrier head 70 and the substrate 10. In some embodiments, the temperature, pressure, and / or flow rate may be independently adjustable for each nozzle or among groups of nozzles.
[0065] For example, when steam 245 is generated (for example, in a steam generator 410), the temperature of steam 245 may be between 90 and 200°C. When steam 245 is dispensed by the nozzle 225, the temperature of steam 245 may be between 90 and 150°C, for example, due to heat loss during transfer. In some embodiments, steam is supplied by the nozzle 225 at a temperature of 70 to 100°C, for example, 80 to 90°C. In some embodiments, the steam supplied by the nozzle is superheated, i.e., at a temperature above its boiling point.
[0066] The flow rate of the steam 245 may be 1 to 1000 cc / min when the steam 245 is supplied by the nozzle 225, depending on the heater output and pressure. In some embodiments, the steam is mixed with other gases, for example, a normal atmosphere or N2. Alternatively, the fluid supplied by the nozzle 225 is substantially pure water. In some embodiments, the steam 245 supplied by the nozzle 225 is mixed with liquid water, for example, aerosolized water. For example, the liquid water and steam may be combined in a relative flow rate ratio of 1:1 to 1:10 (for example, at a flow rate of sccm). However, if the amount of liquid water is small, for example less than 5% by weight, for example less than 3% by weight, for example less than 1% by weight, the steam will have excellent heat transfer properties. Therefore, in some embodiments, the steam is dry steam, i.e., substantially free of water droplets.
[0067] To avoid thermal degradation of the film, water can be mixed with steam 245 to lower its temperature, for example, to around 40-50°C. The temperature of steam 245 can be reduced by mixing cooled water into it, or by mixing water at the same or substantially the same temperature into it (because liquid water transfers less energy than gaseous water).
[0068] In some embodiments, a temperature sensor 214 can be installed in or adjacent to the steam treatment assembly 200 to detect the temperature of the carrier head 70 and / or the substrate 10. The signal from the sensor 214 is received by the controller 12, which can monitor the temperature of the carrier head 70 and / or the substrate 10. Based on the temperature measurement from the temperature sensor 214, the controller 12 can control the supply of steam by the assembly 100. For example, the controller can receive a target temperature value. If the controller 12 detects that the temperature measurement has exceeded the target temperature value, the controller 12 stops the steam flow. In another embodiment, the controller 12 can reduce the steam supply flow rate and / or reduce the steam temperature, for example, to prevent overheating of components during cleaning and / or preheating.
[0069] In some embodiments, the controller 12 includes a timer. In this case, the controller 12 may start when the steam supply is initiated and stop the steam supply when the timer expires. The timer may be set based on empirical testing to achieve desired temperatures for the carrier head 70 and the substrate 10 during washing and / or preheating.
[0070] Figure 2B shows a regulator steam treatment assembly 250, including a housing 255. The housing 255 may take the form of a “cup” for receiving the regulator disc 92 and the regulator head 93. Steam is circulated through a supply line 280 within the housing 255 to one or more nozzles 275. The nozzles 275 can spray steam 295 to remove abrasive by-products, such as debris or slurry particles, left on the regulator disc 92 and / or regulator head 93 after each adjustment operation. The nozzles 275 may be positioned within the housing 255, for example, on the floor, side walls, or ceiling inside the housing 255. One or more nozzles may be positioned to clean the underside of the pad regulator disc and / or the underside, side walls, and / or top surface of the regulator head 93. Steam 295 may be generated using a steam generator 410. The drain pipe 285 can allow excess water, cleaning solution, and cleaning by-products to pass through, preventing accumulation in the housing 255.
[0071] The regulator head 93 and regulator disc 92 can be lowered at least partially into the steam-treated housing 255. When the regulator disc 92 is returned to operation, the regulator head 93 and regulator disc 92 are lifted from the housing 255 and positioned on the polishing pad 30 to adjust the polishing pad 30. When the adjustment operation is complete, the regulator head 93 and regulator disc 92 are lifted from the polishing pad and swung back into the housing cup 255 to remove polishing by-products on the regulator head 93 and regulator disc 92. In some embodiments, the housing 255 is vertically operable and is mounted, for example, on a vertical drive shaft 260.
[0072] The housing 255 is positioned to receive the pad adjuster disc 92 and the adjuster head 93. The adjuster disc 92 and the adjuster head 93 are rotatable and / or vertically movable within the housing 255 so that the nozzle 275 can steam treat various surfaces of the adjuster disc 92 and the adjuster head 93.
[0073] The steam 295 supplied by the nozzle 275 may have an adjustable temperature, pressure, and / or flow rate. In some embodiments, the temperature, pressure, and / or flow rate may be independently adjustable for each nozzle or among groups of nozzles. This allows for variations in the cleaning of the regulator disc 92 or regulator head 93, and therefore makes the cleaning more effective.
[0074] For example, when steam 295 is generated (for example, in a steam generator 410), the temperature of steam 295 may be between 90 and 200°C. When steam 295 is dispensed by the nozzle 275, the temperature of steam 295 may be between 90 and 150°C, for example, due to heat loss during transfer. In some embodiments, steam may be supplied by the nozzle 275 at a temperature of 70 to 100°C, for example, 80 to 90°C. In some embodiments, the steam supplied by the nozzle is superheated, i.e., at a temperature above its boiling point.
[0075] The flow rate of the steam 295 may be 1 to 1000 cc / min when the steam 295 is supplied by the nozzle 275. In some embodiments, the steam is mixed with other gases, for example, with a normal atmosphere or N2. Alternatively, the fluid supplied by the nozzle 275 is substantially pure water. In some embodiments, the steam 295 supplied by the nozzle 275 is mixed with liquid water, for example, aerosolized water. For example, the liquid water and steam may be combined in a relative flow rate ratio of 1:1 to 1:10 (for example, at a flow rate of sccm). However, if the amount of liquid water is small, for example less than 5% by weight, for example less than 3% by weight, for example less than 1% by weight, the steam will have excellent heat transfer properties. Therefore, in some embodiments, the steam is dry steam, i.e., substantially free of water droplets.
[0076] In some embodiments, a temperature sensor 264 may be installed inside or adjacent to the housing 255 to detect the temperature of the regulator head 93 and / or the regulator disk 92. The signal from the temperature sensor 264 is received by the controller 12, which can monitor the temperature of the regulator head 93 or the regulator disk 92 to detect the temperature of the pad regulator disk 92. Based on the temperature measurement from the temperature sensor 264, the controller 12 can control the supply of steam by the assembly 250. For example, the controller may receive a target temperature value. If the controller 12 detects that the temperature measurement has exceeded the target temperature value, the controller 12 stops the flow of steam. In another embodiment, the controller 12 may reduce the steam supply flow rate and / or reduce the steam temperature to prevent overheating of components during cleaning and / or preheating, for example.
[0077] In some embodiments, the controller 12 includes a timer. In this case, the controller 12 may start when the steam supply is initiated and stop when the timer expires. The timer may be set based on empirical testing to achieve a desired temperature of the regulator disc 92 during washing and / or preheating, for example, to prevent overheating.
[0078] Referring to Figure 3A, in some embodiments, the polishing station 20 includes a temperature sensor 64 for monitoring the temperature within the polishing station or within the components of the polishing station, for example, the temperature of the polishing pad 30 and / or the slurry 38 on the polishing pad. For example, the temperature sensor 64 may 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 slurry 38 on the polishing pad. In particular, the temperature sensor 64 may be configured to measure the temperature at multiple points along the radius of the polishing pad 30 in order to generate a radial temperature profile. For example, the IR camera may have a field of view that extends along the radius of the polishing pad 30.
[0079] In some embodiments, the temperature sensor is a contact sensor rather than a non-contact sensor. For example, the temperature sensor 64 may be a thermocouple or IR thermometer placed on or inside the platen 24. Furthermore, the temperature sensor 64 may be in direct contact with the polishing pad.
[0080] In some embodiments, multiple temperature sensors can be spaced apart at various radial positions traversing the polishing pad 30 to provide temperature at multiple points along the radius of the polishing pad 30. This technique can be used as an alternative to or in addition to an IR camera.
[0081] Although shown in Figure 3A as being positioned to monitor the temperature of the polishing pad 30 and / or the slurry 38 on the pad 30, the temperature sensor 64 may be positioned inside the carrier head 70 to measure the temperature of the substrate 10. The temperature sensor 64 can be in direct contact with the semiconductor wafer of the substrate 10 (i.e., a contact sensor). In some embodiments, for example, multiple temperature sensors are included in the polishing station 22 to measure the temperature of the polishing station / various components within the polishing station.
[0082] The polishing system 20 also includes a temperature control system 100 for controlling the temperature of the polishing pad 30 and / or 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, operate by supplying a temperature control medium (e.g., liquid, vapor, or mist) onto the polishing surface 36 of the polishing pad 30 (or onto the polishing fluid already present on the polishing pad).
[0083] In the cooling system 102, the cooling medium may be a gas (e.g., air) or a liquid (e.g., water). The medium may be at room temperature or cooled to below room temperature (e.g., 5 to 15 degrees Celsius). In some embodiments, the cooling system 102 uses a mist of air and liquid (e.g., an aerosolized mist of a liquid such as water). In particular, the cooling system may have a nozzle that produces an aerosolized mist of water cooled to below room temperature. In some embodiments, a solid material may be mixed with the gas and / or liquid. The solid material may be a cooled material (e.g., ice) or a material that absorbs heat when dissolved in water (e.g., by a chemical reaction).
[0084] The cooling medium may be supplied by flowing through one or more openings in the coolant supply arm (e.g., optional holes or slots formed in the nozzle). The openings may be provided by a manifold connected to the coolant supply source.
[0085] As shown in Figures 3A and 3B, the exemplary cooling system 102 includes an arm 110 extending over the platen 24 and the polishing pad 30 from the edge of the polishing pad to or near the center of the polishing pad 30 (for example, within 5% of the total radius of the polishing pad). The arm 110 may be supported by a base 112, which may be supported on the same frame 40 as the platen 24. The base 112 may include one or more actuators, for example, a linear actuator for raising or lowering the arm 110, and / or a rotary actuator for swinging 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 adjustment disc 92, and the slurry dispensing arm 39.
[0086] An exemplary cooling system 102 includes a plurality of nozzles 120 suspended from an arm 110. Each nozzle 120 is configured to spray a liquid cooling medium (e.g., 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 gaps 126.
[0087] Each nozzle 120 may be configured to guide the aerosolized water in the mist 122 to the polishing pad 30. The cooling system 102 may include a liquid cooling medium source 130 and a gas source 132 (see Figure 3B). The liquid from source 130 and the gas from source 132 may be mixed, for example, in or on the arm 110 in a mixing chamber 134 (see Figure 3A) before being guided through the nozzles 120 to generate the mist 122.
[0088] In some embodiments, process parameters, such as flow rate, pressure, temperature, and / or the liquid-to-gas mixing ratio, can be controlled independently for each nozzle. For example, the coolant for each nozzle 120 flows through an independently controllable cooler, allowing for independent control of the mist temperature. In another embodiment, separate sets of pumps for gas and liquid are connected to each nozzle, allowing for independent control of the flow rate, pressure, and gas-to-liquid mixing ratio for each nozzle.
[0089] Various nozzles can be used to spray onto various radial zones 124 on the polishing pad 30. Adjacent radial zones 124 may overlap. In some embodiments, the nozzle 120 generates a mist that collides with the polishing pad 30 along an elongated region 128. For example, the nozzle may be configured to generate a mist within a generally planar triangular space.
[0090] One or more of the elongated regions 128, for example all of the elongated regions 128, may have a longitudinal axis parallel to the radius extending through region 128 (see region 128a). Alternatively, the nozzle 120 generates a conical mist.
[0091] Figure 1 shows a state where the mist itself overlaps, but the nozzles 120 may be oriented so that the elongated regions do not overlap. For example, at least some of the nozzles 120, or for example all of the nozzles 120, may be oriented such that the elongated region 128 is oblique to the radius passing through the elongated region (see 128b).
[0092] At least some of the nozzles 120 may be oriented such that the central axis of the spray from the nozzle (see arrow A) is oblique to the polishing surface 36. In particular, the mist 122 may be directed from the nozzles 120 such that it has a horizontal component in the direction opposite to the direction of movement of the polishing pad 30 within the region of impact caused by the rotation of the platen 24 (see arrow A).
[0093] Figures 3A and 3B show the nozzles 120 arranged at uniform intervals, but this is not necessarily required. The nozzles 120 may be unevenly distributed radially, angularly, or both. For example, the nozzles 120 can be more densely clustered along the radial direction toward the edge of the polishing pad 30. In addition, although Figures 3A and 3B show nine nozzles, there may be more or fewer nozzles, for example, from three to twenty nozzles.
[0094] In the heating system 104, the heating medium may be a gas, such as steam (e.g., from a steam generator 410), heated air, or a liquid, such as heated water, or a combination of gas and liquid. The medium is above room temperature (e.g., 40 to 120 degrees Celsius, e.g., 90 to 110 degrees Celsius). The medium may be water (substantially pure deionized water, or water containing additives or chemicals). In some embodiments, the heating system 104 uses steam atomization. The steam may contain additives or chemicals.
[0095] The heating medium may be supplied by flowing through openings (e.g., holes or slots provided by one or more nozzles) on the heating supply arm. The openings may be provided by a manifold connected to the heating medium supply source.
[0096] An exemplary heating system 104 includes an arm 140 extending over the platen 24 and the polishing pad 30 from the edge of the polishing pad to or near the center of the polishing pad 30 (for example, within 5% of the total radius of the polishing pad). The arm 140 may be supported by a base 142, which may be supported on the same frame 40 as the platen 24. The base 142 may include one or more actuators, such as a linear actuator for raising or lowering the arm 140, and / or a rotary actuator for swinging the arm 140 laterally over the platen 24. The arm 140 is positioned to avoid collisions with other hardware components such as the polishing head 70, the pad adjustment disc 92, and the slurry dispensing arm 39.
[0097] Along the rotational direction of the platen 24, the arm 140 of the heating system 104 can be positioned between the arm 110 of the cooling system 102 and the carrier head 70. Along the rotational direction of the platen 24, the arm 140 of the heating system 104 can be positioned between the arm 110 of the cooling system 102 and the slurry supply arm 39. For example, the arm 110 of the cooling system 102, the arm 140 of the heating system 104, the slurry supply arm 39, and the carrier head 70 can be arranged in a sequence along the rotational direction of the platen 24.
[0098] Multiple openings 144 are formed within the lower surface of the arm 140. Each opening 144 is configured to guide a gas or vapor, such as steam, onto the polishing pad 30. The arm 140 may be supported by a base 142 such that the openings 144 are separated from the polishing pad 30 by gaps. The gaps may be 0.5 to 5 mm. In particular, the gaps may be selected so that the heat of the heating fluid does not dissipate significantly before the fluid reaches the polishing pad. For example, the gaps can be selected so that the steam released from the openings does not condense before reaching the polishing pad.
[0099] The heating system 104 may include a steam source 148, such as a steam generator 410, which may be connected to the arm 140 by a pipe. Each opening 144 may be configured to guide steam to the polishing pad 30.
[0100] In some embodiments, process parameters, such as flow rate, pressure, temperature, and / or liquid-gas mixing ratio, can be controlled independently for each nozzle. For example, the fluid for each opening 144 flows through an independently controllable heater, allowing for independent control of the temperature of the heated fluid, such as the temperature of water vapor.
[0101] Various openings 144 can guide water vapor onto different radial zones on the polishing pad 30. Adjacent radial zones may overlap. Optionally, some of the openings 144 may be oriented such that the central axis of the spray from the opening is oblique to the polishing surface 36. Water vapor can be guided from one or more of the openings 144 such that it has a horizontal component in the direction opposite to the direction of movement of the polishing pad 30 within the region of impact caused by the rotation of the platen 24.
[0102] Figure 3B shows the openings 144 arranged at uniform intervals, but this is not necessarily 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. In another embodiment, the openings 144 may be more densely clustered in a radius corresponding to the radius at which the polishing fluid 38 is supplied to the polishing pad 30 by the slurry supply arm 39. Furthermore, although Figure 3B shows nine openings, there may be more or fewer openings.
[0103] The polishing system 20 may also include a high-pressure rinsing system 106. The high-pressure rinsing system 106 includes a number of nozzles 154 (e.g., 3 to 20 nozzles) that guide a cleaning fluid, such as water, onto the polishing pad 30 with high force to clean the pad 30 and remove used slurry, polishing debris, etc.
[0104] As shown in Figure 3B, an exemplary rinsing system 106 includes an arm 150 extending over the platen 24 and the polishing pad 30 from the edge of the polishing pad to or near the center of the polishing pad 30 (for example, within 5% of the total radius of the polishing pad). The arm 150 may be supported by a base 152, which may be supported on the same frame 40 as the platen 24. The base 152 may include one or more actuators, for example, a linear actuator for raising or lowering the arm 150, and / or a rotary actuator for swinging the arm 150 laterally over the platen 24. The arm 150 is positioned to avoid collisions with other hardware components such as the polishing head 70, the pad adjustment disc 92, and the slurry dispensing arm 39.
[0105] Along the rotational direction of the platen 24, the arm 150 of the rinsing system 106 may be located between the arm 110 of the cooling system 102 and the arm 140 of the heating system 104. For example, the arm 110 of the cooling system 102, the arm 150 of the rinsing system 106, the arm 140 of the heating system 104, the slurry supply arm 39, and the carrier head 70 can be arranged in a sequence along the rotational direction of the platen 24. Alternatively, along the rotational direction of the platen 24, the arm 110 of the cooling system 102 may be located between the arm 150 of the rinsing system 106 and the arm 140 of the heating system 104. For example, the arm 150 of the rinsing system 106, the arm 110 of the cooling system 102, the arm 140 of the heating system 104, the slurry supply arm 39, and the carrier head 70 can be arranged in a sequence along the rotational direction of the platen 24.
[0106] Figure 3B shows the openings 154 arranged at uniform intervals, but this is not necessarily required. In addition, while Figures 3A and 3B show nine nozzles, there may be more or fewer nozzles, for example, from three to twenty nozzles.
[0107] The polishing system 2 may also include a controller 12 for controlling the operation of various components, such as a temperature control system 100. The controller 12 is configured to receive temperature measurements from a temperature sensor 64 for each radial zone of the polishing pad. The controller 12 can compare the measured temperature profile with a desired temperature profile and generate a feedback signal to a control mechanism (e.g., actuator, power supply, pump, valve, etc.) for each nozzle or opening. The feedback signal is calculated by the controller 12, for example, 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 reach (or at least approach) the desired temperature profile.
[0108] In some embodiments, the polishing system 20 includes a wiper blade or body 170 to uniformly disperse the polishing fluid 38 across the polishing pad 30. Along the rotational direction of the platen 24, the wiper blade 170 may be located between the slurry supply arm 39 and the carrier head 70.
[0109] Figure 3B shows separate arms for each subsystem, e.g., a heating system 104, a cooling system 102, and a rinsing system 106, and various subsystems can be included in a single assembly supported by a common arm. For example, the assembly may include a cooling module, a rinsing module, a heating module, a slurry supply module, and an optional wiper module. Each module may include a body, e.g., a curved body, which 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 on the polishing pad 30. Various fluid supply components, e.g., pipes and passages, may extend inside each body. In some embodiments, the modules are individually removable from the mounting plate. Each module may have similar components for performing the functions of the arm of the associated system described above.
[0110] Referring to Figures 1, 2A, 2B, 3A, and 3B, the controller 12 may monitor temperature readings received by sensors 64, 214, and 264 and control the amount of steam supplied to the temperature control system 100 and the steam processing assemblies 200 and 250. The controller 12 may continuously monitor temperature readings and control the temperature within a feedback loop to adjust the temperatures of the polishing pad 30, the carrier head 70, and the regulating disc 92. For example, the controller 12 may receive the temperature of the polishing pad 30 from sensor 64 and control the supply of steam to the carrier head 70 and / or regulating head 92 to raise the temperature of the carrier head 70 and / or regulating head 92 to match the temperature of the polishing pad 30. Reducing the temperature difference helps prevent the carrier head 70 and / or regulating head 92 from acting as a heat sink on the relatively hot polishing pad 30, thereby improving uniformity within the wafer.
[0111] In some embodiments, the controller 12 stores desired temperatures for the polishing pad 30, carrier head 70, and regulator disk 92. The controller 12 monitors temperature readings from sensors 64, 214, and 264 and controls the temperature control system 100 and the steam treatment assembly 200 and / or 250 to bring the temperatures of the polishing pad 30, carrier head 70, and / or regulator disk 92 to the desired temperatures. By achieving the desired temperatures, the controller 12 can improve uniformity within the wafer and uniformity between wafers.
[0112] Alternatively, the controller 12 can raise the temperature of the carrier head 70 and / or the regulator head 92 slightly higher than the temperature of the polishing pad 30, and then lower it to the same or substantially the same temperature as the polishing pad 30 when the carrier head 70 and / or the regulator head 92 move from their respective washing and preheating stations to the polishing pad 30.
[0113] Numerous embodiments of the present invention have been described. However, it should be understood that various modifications are possible without departing from the essence and scope of the invention. Therefore, other embodiments are also included in the following claims.
Claims
1. Apparatus for steam treatment of carrier heads or substrates in a chemical mechanical polishing system, Road Cup and, A pedestal in a cavity defined by the load cup, configured to receive a substrate from or supply the substrate to the carrier head, A boiler for generating steam, One or more nozzles are positioned to guide water vapor inward into the cavity defined by the load cup, A supply line extending from the boiler to the one or more nozzles, for supplying steam to the one or more nozzles, A temperature sensor for monitoring the temperature of the carrier head and / or the substrate, An apparatus comprising: a temperature sensor that receives the temperature and a controller configured to control the supply of water vapor to the carrier head and / or the substrate based on the temperature from the temperature sensor in order to bring the temperature of the carrier head and / or the substrate to a desired temperature.
2. The apparatus according to claim 1, further comprising a motor for rotating the carrier head when the carrier head is inside the load cup.
3. The apparatus according to claim 1, further comprising an actuator for raising and lowering the carrier head inside the load cup.
4. The apparatus according to claim 1, wherein the controller is configured to stop the flow of water vapor when the carrier head or the substrate reaches a target temperature.
5. The apparatus according to claim 1, wherein the controller is configured to start a timer when the water vapor begins to flow onto the carrier head or the substrate, and to stop the flow of water vapor when the timer expires.
6. The apparatus according to claim 1, wherein the one or more nozzles include a first nozzle, and the controller is configured to flow steam through the first nozzle to the outer surface of the carrier head when the carrier head is positioned in the load cup.
7. The apparatus according to claim 1, wherein the one or more nozzles include a second nozzle, and the controller is configured to flow water vapor through the second nozzle to the inner surface of the carrier head when the substrate is positioned on the pedestal.
8. The apparatus according to claim 1, wherein the one or more nozzles include a third nozzle, and the controller is configured to flow water vapor through the third nozzle onto the upper surface of the substrate when the substrate is positioned on the pedestal.
9. Apparatus for steam treatment of regulator heads and / or regulator discs in a chemical mechanical polishing system, Regulator cleaning cup and A boiler for generating steam, One or more nozzles are positioned to guide steam inward into the cavity defined by the regulator cleaning cup, A supply line extending from the boiler to the one or more nozzles, for supplying steam to the one or more nozzles, A temperature sensor for monitoring the temperature of the regulator head and / or the regulator disk, An apparatus comprising: a temperature sensor that receives the temperature and a controller configured to control the supply of water vapor to the regulator head and / or the regulator disk based on the temperature from the temperature sensor in order to bring the temperature of the regulator head and / or the regulator disk to a desired temperature.
10. The apparatus according to claim 9, wherein the controller is configured to stop the flow of water vapor to the regulator head or the regulator disk when the regulator head or the regulator disk reaches a target temperature.
11. The apparatus according to claim 9, wherein the controller is configured to start a timer when the steam begins to flow onto the regulator head or the regulator disk, and to stop the flow of steam when the timer expires.
12. The apparatus according to claim 9, wherein the one or more nozzles include a first nozzle, and the controller is configured to flow steam through the first nozzle to the lower surface of the regulator disc when the regulator head is positioned in the regulator cleaning cup.
13. The apparatus according to claim 9, wherein the one or more nozzles include a second nozzle, and the controller is configured to flow steam through the second nozzle to the outer surface of the regulator head when the regulator head is positioned in the regulator cleaning cup.