Polishing control using coolant

Abstract

The chemical mechanical polishing apparatus includes a platen for holding a polishing pad, a carrier for holding a substrate in contact with the polishing surface of the polishing pad during the polishing process, a polishing fluid dispenser positioned on the platen and having a polishing fluid port for supplying polishing fluid onto the polishing pad, and a temperature control system comprising a coolant reservoir for containing coolant fluid, a temperature controller configured to control the temperature of the coolant fluid in the coolant reservoir, a first dispenser having an opening fluid-connected to the coolant reservoir, the positioned opening configured to spray aerosolized coolant fluid directly onto the polishing pad, and a second dispenser having a coolant port fluid-connected to the coolant reservoir, the coolant port positioned on the platen and configured to direct the flow of coolant fluid directly onto the polishing pad.

Description

Technical Field

[0001]

[0001] The present disclosure relates to chemical mechanical polishing, and more specifically, to control of polishing rate during a polishing process.

Background Art

[0002]

[0002] Integrated circuits are typically formed on a substrate by sequentially depositing conductive layers, semiconductive layers, or insulating layers on a silicon wafer. Certain manufacturing steps involve depositing a fill layer over a non-planar surface and planarizing the fill layer. In specific applications, the conductive fill layer is planarized until the top surface of the patterned layer is exposed. In other applications such as oxide polishing, the fill layer is planarized until a predetermined thickness remains over the non-planar surface. Furthermore, planarization of the substrate surface is usually required in photolithography.

[0003]

[0003] Chemical mechanical polishing (CMP) is recognized as one of the planarization methods. In this planarization method, it is usually necessary to attach the substrate to a carrier or polishing head. The exposed surface of the substrate is typically pressed against a rotating polishing pad. The carrier head applies a controllable load to the substrate to press the substrate against the polishing pad. A polishing liquid, for example, a polishing slurry, is usually supplied to the surface of the polishing pad.

[0004]

[0004] During several chemical mechanical polishing processes, it is desirable to perform different steps of the entire polishing process at different polishing rates. For example, it may be desirable to perform a bulk polishing step at a higher polishing rate than a clearing step. A conventional approach is to perform different steps, for example, the bulk polishing step and the clearing step, on separate platens, for example, with different slurries or different applied loads.

Summary of the Invention

[0005]

[0005] Embodiments disclosed herein generally include a chemical mechanical polishing apparatus, the apparatus comprising: a platen for holding a polishing pad; a carrier for holding a substrate in contact with the polishing surface of the polishing pad during the polishing process; a polishing fluid dispenser positioned on the platen and having a polishing fluid port for supplying polishing fluid onto the polishing pad; a temperature control system comprising: one or more coolant reservoirs for containing one or more coolant liquids; a temperature controller configured to control the temperature of one or more coolant liquids in the one or more coolant reservoirs; a first dispenser having a plurality of openings fluidly connected to one or more coolant reservoirs, wherein the plurality of openings are positioned on the platen and configured to spray aerosolized coolant liquid directly onto the polishing pad; and a second dispenser having a coolant port fluidly connected to one or more coolant reservoirs, wherein the coolant port is positioned on the platen and configured to direct a flow of coolant liquid directly onto the polishing pad.

[0006]

[0006] Embodiments disclosed herein generally include a chemical mechanical polishing system comprising two polishing stations, each station comprising: a platen for holding a polishing pad; a carrier for holding a substrate in contact with the polishing surface of the polishing pad during the polishing process; a polishing fluid dispenser positioned on the platen and having a polishing fluid port for supplying polishing fluid onto the polishing pad; and a coolant dispenser positioned on the platen and having a coolant port for supplying coolant fluid onto the polishing pad; and a temperature control system comprising: a coolant fluid reservoir for holding coolant fluid and configured to supply coolant fluid to each coolant port of each polishing station; and a temperature controller configured to control the temperature of the coolant fluid in the coolant fluid reservoir.

[0007]

[0007] Embodiments disclosed herein generally include methods for controlling a chemical mechanical polishing process, in a polishing process which may include at least a bulk removal step and a clearing step, the methods comprising polishing a substrate on the surface of a polishing pad, determining a desired temperature for the bulk removal step, spraying a coolant onto the polishing pad to bring the polishing pad to a desired temperature during the bulk removal step, detecting a transition from the bulk removal step to the clearing step, and distributing and flowing the coolant onto the surface to lower the temperature of the polishing pad in response to the detection of the transition from the bulk removal step to the clearing step.

[0008]

[0008] The examples may include one or more of the following features: In this method, the coolant is deionized water. This method may include controlling the temperature of the coolant to less than 5°C during the polishing process.

[0009]

[0009] The advantages may optionally include one or more of the following: The polishing speed can be suddenly and abruptly reduced without removing the substrate from the platen. Multiple consecutive polishing steps, such as bulk polishing and clearing, can be performed on the same platen, thus increasing throughput and flexibility in the use of other platens. Consumable costs can be reduced without wasting coolant fluid, such as deionized water (DI water), and the need for large amounts of wastewater around the platen can be reduced.

[0010]

[0010] Details of one or more implementations are described in the accompanying drawings and the following description. Other embodiments, features, and advantages will become apparent from the description and drawings, as well as the claims. [Brief explanation of the drawing]

[0011] [Figure 1A] This is a schematic cross-sectional view of a polishing system including a pad conditioner system for distributing a low-temperature coolant liquid from a rinse armature onto the pad. [Figure 1B]This is a schematic cross-sectional view of a polishing system including a pad conditioner system for distributing a low-temperature coolant liquid from a slurry armature onto the pad. [Figure 2] This is a schematic cross-sectional view of a polishing system including a temperature control system for controlling the temperature of the coolant fluid. [Figure 3] This is a schematic cross-sectional view of a polishing system including another implementation embodiment of a temperature control system for controlling the temperature of the coolant fluid. [Figure 4] This is a schematic cross-sectional view of a polishing system including two platens, each having a temperature control arm and associated temperature control system. [Modes for carrying out the invention]

[0012]

[0016] Similar reference numbers and notations in various drawings indicate the same elements.

[0013]

[0017] As mentioned above, it is desirable to perform different steps of the entire polishing process at different polishing rates. For example, a bulk removal step, in which the majority of the film thickness is removed, can be performed at a relatively high polishing rate, followed by a clearing step in which the remaining film thickness is removed at a relatively low polishing rate to expose the underlying structure beneath the film. The problem with performing different steps on different platens is the reduction in throughput, i.e., the time required to move the substrate to a new platen. On the other hand, the problem with performing different steps sequentially on the same platen is that the high polishing rate at the end of the bulk removal step may affect the start of the clearing step. For example, simply reducing the pressure or changing the slurry applied to the substrate may not immediately reduce the polishing rate to the lower rate expected with the lower pressure or new slurry. This effect can be called the "polishing rate momentum" and may be related to the temperature and persistence of polishing particles between polishing steps, without being limited to any particular theory. The polishing rate momentum from the bulk removal step may make it difficult to control wafer clearing with in-situ measurements. During the clearing step, high polishing speeds can lead to uneven clearing of the wafer, potentially causing undesirable dishing and erosion (hot spots) on the patterned wafer, possibly at the wafer edges.

[0014]

[0018] Overall, to quickly change from a high to a low polishing speed, for example, to overcome the "momentum of polishing speed," it may be necessary to change the polishing speed through process temperature changes. One approach is to add a "quenching" step between the bulk removal step and the clearing step. In a typical quenching step, a large amount of room temperature DI water is distributed to the polishing surface under high pressure. This can wash away the previous polishing fluid and lower the temperature of the polishing pad. However, this type of quenching typically results in high process costs because more than 10 liters of DI water are usually distributed in a single high-pressure rinse (HPR) quenching step.

[0015]

[0019] A technique that can address this problem is to dispense low-temperature liquid DI water to reduce the polishing speed. Low-temperature liquid DI water requires less fluid (e.g., 100cc or 0.1L) compared to a high-pressure rinsing step.

[0016]

[0020] Current cooling methods can involve implementing a fluid mist (e.g., deionized (DI) water) to gradually cool the platen during the polishing process. However, the mist does not reduce the rate of polishing speed quickly enough to facilitate precise control or a high rate of change of polishing speed during the bulk removal step and the clearing step, or between the bulk removal step and the clearing step. Low-temperature liquid DI water distributed directly onto the platen in one go rapidly lowers the surface temperature of the polishing pad. As a result, the polishing speed decreases rapidly.

[0017]

[0021] Polishing processes using high-speed slurries can be stopped or paused at smaller layer thicknesses before moving on to the clearing step, while still preventing film breakage due to the "momentum of polishing speed." In other words, a quenching step with low-temperature liquid DI rapidly reduces the polishing speed, facilitating the use of high-speed slurries without significantly increasing dishing or erosion. Because more thickness can be removed at high speed during the bulk polishing step, the total process time can be reduced, potentially improving throughput.

[0018]

[0022] By distributing low-temperature liquid DI, logistics in the chemical mechanical polishing process can be simplified by reducing the use of consumables and eliminating the need to switch to a different slurry, move the substrate to a different platen, or use an HPR speed quenching intermediate process that may involve using large amounts of fluid, such as 10L or more.

[0019]

[0023] Distributing a low-temperature coolant can reduce the polishing rate for improving metal topography by reducing metal loss on the patterned wafer (PTW) after polishing at the first platen of the polishing system. For example, distributing a low-temperature coolant reduces the polishing rate for copper (Cu) topography, reducing Cu loss on the PTW. Reducing the polishing rate allows for longer clearing polishing steps for more controlled topography, promoting a lower final thickness while reducing dishing and erosion on an angstrom scale, for example.

[0020]

[0024] By distributing a low-temperature coolant, a high rate of change in polishing speed can be obtained at high coolant-to-slurry ratios. In one embodiment, distributing a high ratio of low-temperature coolant to slurry (e.g., 5:1 coolant:slime, or 10:1 coolant:slime) reduces the polishing speed in a short time. Alternatively, replacing the slurry flow to the polishing pad with low-temperature coolant stops polishing as the slurry is removed from the pad. In one embodiment, the polishing speed of the substrate can be substantially reduced by flushing the slurry from the pad with 100cc to 200cc of low-temperature coolant. At other coolant-to-slurry ratios, e.g., 1:1 coolant-to-slurry, the polishing speed is reduced sufficiently to facilitate fine control of the final thickness, e.g., at the angstrom level. The reduction in polishing speed may vary depending on the desired speed and consumable set.

[0021]

[0025] As used herein, the term "low temperature" refers to temperatures in the range of 0°C to 5°C. Fluids in this range remain liquid without freezing and have a higher cooling capacity than fluids at temperatures above this range. In implementations where water is used as the coolant, water has a larger heat capacity than other coolants, so applying low-temperature water to the surface of the polishing pad results in a larger temperature change.

[0022]

[0026] FIG. 1A shows a polishing system 20 operable to polish a substrate 10. The polishing system 20 includes a rotatable platen 24 on which a polishing pad 30 is disposed. The platen 24 is operable to rotate about an axis 25. For example, a motor 22 can rotate a drive shaft 28 to rotate the platen 24. The polishing pad 30 may be a two-layer polishing pad having an outer polishing layer 34 with a polishing surface 36 and a softer backing layer 32.

[0023]

[0027] The polishing system 20 includes, for example, a supply port 64 provided at an end of a slurry distribution arm 62 for distributing a polishing liquid 60 such as polishing slurry onto the polishing pad 30. The polishing system 20 can also include a polishing pad conditioner that abrades the polishing pad 30 to maintain the polishing pad 30 in a consistent polishing state.

[0024]

[0028] The polishing system 20 includes a carrier head 70 operable to hold the substrate 10 in contact with the polishing pad 30, such as during a polishing process. The carrier head 70 can include a flexible membrane 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 different zones on the substrate 10, for example, different radial zones. There may be one, two, or four or more, for example five, chambers.

[0025]

[0029] The carrier head 70 is suspended from a support structure 72, such as a carousel or track, and is connected to a carrier head rotary motor 76 by a carrier drive shaft 74 so that the carrier head can rotate around an axis 71. Furthermore, the carrier head 70 can swing laterally over the entire polishing pad 30, for example, by being driven by an actuator and moving within a radial slot of the support structure 72, or by the rotation of a motor-driven carousel, or by being driven by an actuator and moving back and forth along a track. In a normal process, the platen 24 rotates around its central axis 25, and the carrier head 70 rotates around its central axis 71, translating laterally across the entire upper surface of the polishing pad 30. A controller 190, such as a programmable computer, is connected to motors 22 and 76 to control the rotational speeds of the platen 24 and the carrier head 70.

[0026]

[0030] The polishing system 20 includes a temperature control system 100 that controls the temperature of the polishing pad 30 by distributing low-temperature liquid DI water onto the pad 30. The temperature control system 100 includes at least one temperature control arm 102 that extends over the platen 24 and the polishing pad 30 from the edge of the polishing pad 30 to the center of the polishing pad 30, or at least near there (e.g., less than 5% of the total radius of the polishing pad).

[0027]

[0031] The temperature control arm 102 may be supported by a base 104, which may be supported on the same frame 40 as the platen 24. The base 104 may include one or more actuators, for example, a linear actuator for raising or lowering the temperature control arm 102, and / or a rotary actuator for swinging the temperature control arm 102 laterally on the platen 24.

[0028]

[0032] The temperature control arm 102 is positioned to avoid collisions with other hardware components such as the slurry distribution arm 62, the polishing head 70, and the conditioner system. The temperature control arm 102 of the temperature control system 100 may be located between the carrier head 70 and the slurry distribution arm 62, along the rotational direction of the platen 24.

[0029]

[0033] The temperature control system 100 includes two dispensers that supply low-temperature liquids: a "quenching" dispenser 140 that supplies a low-temperature liquid onto the polishing pad 30 all at once, for example as a flowing fluid, in order to rapidly reduce the temperature and polishing speed; and a "process control" dispenser 130 that supplies a low-temperature liquid at a relatively low flow rate, for example as a spray, in order to control the temperature of the polishing pad 30 during the polishing step in progress at a lower rate of temperature change, for example to compensate for the gradual accumulation of heat during the polishing process.

[0030]

[0034] The polishing system 20 may also include a rinse fluid dispenser 150 that supplies a relatively large amount of rinse fluid 152 from a nozzle 154, for example, in a high-pressure rinse, to wash away the polishing fluid 60 from the polishing pad 30. The rinse fluid 152 may be at room temperature. In some embodiments, the rinse fluid dispenser 150 supplies a constant amount of rinse fluid 152 at a supply rate ranging from 1 liter (L) / min to 10 L / min (e.g., 2 L to 8 L / min, or 5 L to 7 L / min).

[0031]

[0035] The quenching dispenser 140 cools the surface 36 during the polishing process, lowering the temperature of the surface 36 with a short time and a small amount of coolant. The quenching dispenser 140 controls the temperature of the surface 36 by rapidly distributing temperature-controlled coolant 66 from the supply source 142 onto the surface 36 of the polishing pad 30. The coolant 66 is DI water cooled to 5°C or less (e.g., in the range of 0°C to 5°C) by a coolant management system 110 that controls the temperature of the supply source 142.

[0032]

[0036] The quenching dispenser 140 may include one or more ports 68 on the arm 102 to distribute coolant liquid 66 onto zone 128 on the surface 36 of the pad 30. The ports 68 are connected to a coolant management system 110 via channels, such as pipes, flexible tubes, or passages through the arm 102, and are connected to a temperature-controlled supply source 142. Although two ports 68 are shown in Figure 1A, there may be only one port 68, or there may be three or more.

[0033]

[0037] When the controller 190 determines that the high polishing speed step has ended and the low polishing speed step has begun, the controller 190 instructs the temperature control system 100 to distribute cooled coolant liquid 66 from the quenching dispenser 140 onto the pad 30 in order to reduce the polishing speed at short intervals. In one embodiment, the controller 190 causes the temperature control system 100 to begin distributing the cooled coolant liquid 66 within 5 seconds (e.g., within 3 seconds, within 1 second) of the start of the low polishing speed step. In some implementations, the controller 190 causes the cooled coolant liquid 66 to be distributed for a maximum of 1 to 10 seconds, for example, between 3 and 8 seconds. In some implementations, the temperature control system 100 distributes a preset amount of low-temperature liquid 66 from the quenching dispenser 140.

[0034]

[0038] The controller 190 determines the new temperature of the surface 36 after a preset amount of liquid 66 has been dispensed, and dispenses additional liquid 66 if further correction is needed to achieve the target temperature. In some embodiments, the target temperature is achieved by the temperature control system 100 within 10 seconds (e.g., within 8 seconds, within 5 seconds). In some embodiments, the target polishing speed is achieved by the temperature control system 100 within 10 seconds (e.g., within 8 seconds, within 5 seconds). Achieving the target polishing speed and / or target temperature within a short (e.g., less than 10 seconds) window is beneficially improved in terms of the accuracy of the final layer thickness.

[0035]

[0039] In another embodiment, the controller 190 transmits a target polishing speed to a temperature control system 100, which determines the amount of cooled coolant liquid 66 to be distributed. The amount of liquid 66 distributed by the system 100 is sufficient to reduce the measured polishing speed to below the target polishing speed. For example, the amount of coolant liquid 66 distributed may be in the range of 0.01 L to 0.1 L (e.g., 10 mL to 100 mL, 10 cc to 100 cc).

[0036]

[0040] Although we do not wish to be limited to theory, the cooled coolant liquid 66 reduces the polishing speed by pushing the polishing liquid 60 away from the lower surface 36 of the substrate 10 and by lowering the temperature of the polishing pad 30, thereby lowering the temperature at the junction between the substrate 10 and the polishing surface 36. This reduces the chemical reaction rate of the polishing chemicals present in the liquid 60.

[0037]

[0041] The coolant management system 110 controls the temperature of the coolant liquid 66 in the supply source 142 so that the coolant liquid 66 is at a low temperature when distributed from the port 68. The coolant management system 110 includes at least one supply source 142 for holding a certain amount of liquid 66, and a temperature controller and cooling element for determining and controlling the temperature of the liquid 66 in the supply source 142 of the coolant management system 110. Some embodiments of the coolant management system 110 include a connection to a supply source of coolant liquid 66 that supplies liquid 66 to the coolant management system 110 for temperature control and distribution to the pad 30. Embodiments of the coolant management system 110 are further described herein with reference to Figures 2, 3, and 4.

[0038]

[0042] The process control dispenser 130 is configured to deliver a spray of coolant 120, which may have the same composition as the coolant 66, from one or more openings 106 in, for example, one or more nozzles 108. The nozzles may be formed within or suspended from the temperature control arm 102. During operation, the arm 102 is supported by a base 104 such that the nozzles 108 are separated from the polishing pad 30 by a gap 126. The gap 126 may be between 1 cm and 10 cm.

[0039]

[0043] Various openings 106 of the process control dispenser 130 guide the injection 122 of coolant liquid 120, which is sprayed onto different radial zones 124 on the polishing pad 30. Adjacent radial zones may overlap. Optionally, some of the openings 106 can be oriented such that the central axis of the spray from that opening is at an oblique angle with respect to the polishing surface 36. The spray can be directed from one or more of the openings 106 such that it has a horizontal component in the impact region in the direction opposite to the direction of motion ω of the polishing pad 30 due to the rotation of the platen 24.

[0040]

[0044] Figure 1A illustrates equally spaced openings 106 and nozzles 108 of the process control dispenser 130, but this is not mandatory. The openings, for example, the nozzles 108, may be unevenly distributed in the radial, angular, or both directions. For example, the openings 106 may be more densely packed toward the outer edge of the polishing pad 30 (to compensate for a larger area covered by the outer radius). Furthermore, although Figure 1A illustrates seven openings 106, the number of openings 106 may be more or less. The liquid spray 122 may include temperature-controlled liquid 120 from the coolant management system 110, which is aerosolized liquid spray, for example, atomized by the nozzles 108. The coolant management system 110 includes a reservoir 132 for storing and controlling the temperature of a certain amount of liquid 120. In other embodiments, the coolant management system 110 includes a single reservoir, for example, a source 142 or reservoir 132, from which a common coolant fluid 66 is supplied to both a process control dispenser 130 and a quenching dispenser 140.

[0041]

[0045] The ports or openings of the process control dispenser 130, the quenching dispenser 140, and the rinse fluid dispenser 150 are supported by the control arm 102. For example, the control arm 102 supports the nozzles 108, port 68, and nozzle 154 associated with the dispensers 130, 140, and 150. In other embodiments, each of the dispensers 130, 140, and 150, as well as the associated nozzles 108, port 68, and nozzle 154, may be supported by separate arms or combinations of arms.

[0042]

[0046] Figure 1B shows another configuration of the temperature control system 100 in which coolant 66 is distributed from an opening 69 on a slurry distribution arm 62. The coolant 66 may be distributed simultaneously with, for example, the polishing fluid 60, or partially overlapping with it. The coolant 66 may be distributed with the polishing fluid 60 in a desired ratio. In one embodiment, the coolant 66 is distributed simultaneously with the polishing fluid 60 from the opening 69 of the slurry distribution arm 62 in a desired ratio. In one embodiment, the coolant 66 is distributed in an amount sufficient to flush the polishing fluid 60 on the polishing pad 30 (e.g., a polishing speed of 20 angstroms / min or less, e.g., 10 angstroms / min) to stop the polishing process. Such low speeds are beneficial for controlling topography close to angstrom resolution.

[0043]

[0047] An embodiment of the coolant management system 110 includes a single supply source 142 connected to a heating element, a cooling element, or both, to control the temperature of the coolant liquid 66 in the supply source 142. Figure 2 shows a temperature control system 200 having a coolant management system 210 connected to a quenching dispenser 140. The coolant management system 210 includes a temperature controller 212 connected to temperature control elements 214a and 214b. Elements 214a and 214b are a heating element 214a and a cooling element 214b.

[0044]

[0048] The controller 212 is electrically connected to a temperature sensor 205 located inside a reservoir 204 containing the coolant liquid 66. The controller 212 receives temperature data from the sensor 205 and controls elements 214a and / or 214b to heat or cool the coolant liquid 66 in the reservoir 204 to achieve a desired temperature. Specifically, the coolant liquid 66 can be cooled to 5°C or less (for example, within the range of 0°C to 5°C). Exemplary temperature control systems 200 and reservoirs 204 can provide the coolant control system 110, as well as reservoirs 132 and 142, shown in Figure 1A.

[0045]

[0049] The controller 212 is connected to a three-way diversion valve 202 and a three-way selection valve 203. The input of the diversion valve 202 is connected to a coolant liquid source 266, such as a public water pipe, a filtration system, a distillation feed source, or a deionized water supply source. One output of the diversion valve 202 is connected to the input of the three-way valve 203, and the other output of the diversion valve 202 is connected to the reservoir 204, so that the valve 202 can supply coolant liquid 66 from the coolant liquid source 266 to either the valve 203 and port 68 without temperature control, or to the reservoir 204 with temperature control.

[0046]

[0050] The selection valve 203 has one input connected to the flow diversion valve 202 and another input connected to the reservoir 204. The output of the selection valve 203 is connected to port 68, so that coolant 66 received directly from the coolant source 266 through valve 202, or temperature-controlled coolant 66, 120 from reservoir 204, is directed to port 68. Although not shown in Figure 2, in some embodiments, one or more pumps generate pressure within the temperature control system 200 and supply pressurized coolant 66 through port 68.

[0047]

[0051] In some embodiments, the coolant control system 110 includes a plurality of reservoirs for containing polishing fluid 60 or coolant fluid 66, 120 that are heated or cooled independently. Figure 3 shows an exemplary temperature control system 300, which includes a coolant control system 310 housing reservoirs for polishing fluid 60 and coolant fluid 66 that are distributed by a quenching dispenser 140 supported by a control arm 102. The coolant control system 310 includes three separate reservoirs, referred to as reservoirs 304, 306, and 308. Reservoir 304 contains polishing fluid 60, and reservoirs 306 and 308 contain coolant fluid 66. Reservoir 304 is fluid-coupled to a supply port 64 supported by the arm 102 for distributing the fluid 60 to the pad 30 during the polishing process.

[0048]

[0052] Generally, each reservoir can be independently temperature-controlled by a temperature controller 312 that contacts the associated reservoir and activates a specific temperature control element (e.g., a heater or cooler). Reservoirs 306 and 308 are in contact with temperature control elements 314a and 314b, respectively, and in the embodiment of Figure 2, reservoir 304 is not temperature-controlled. Temperature control element 314b is a cooling element, and the coolant liquid 66 in reservoir 308 is cooled. Temperature control element 314a is a heater, and the coolant liquid 66 in reservoir 306 is heated.

[0049]

[0053] Reservoirs 306 and 308 are fluid-coupled to a three-way valve 302 connected to a temperature controller 312. The temperature controller 312 controls the gate state of valve 302 so that the fluid received by valve 302 from reservoir 306 or reservoir 308 is directed to port 68. One embodiment of valve 302 is a two-way valve, for example, in which either coolant 66 from reservoir 306 or coolant 66 from reservoir 308 is directed to port 68. Another embodiment of valve 302 facilitates the distribution of coolant 66 from reservoir 306 or reservoir 308 in a specific ratio. In such embodiments, the valve 302 allows simultaneous distribution from reservoir 306 and reservoir 308 in any ratio between the total coolant 66 from reservoir 306 (e.g., 100% heated coolant 66) and the total coolant 66 from reservoir 308 (e.g., 100% cooled coolant 66). The ratio between heated coolant 66 and cooled coolant 66 can be controlled by the temperature controller 312 to achieve a desired temperature at the outlet or port 68 of the valve 302.

[0050]

[0054] Valve 302 may include a temperature sensor that generates temperature data and transmits that data to the temperature controller 312, or the temperature sensor may be mounted inline at the downstream outlet of valve 302. The temperature controller 312 controls valve 302 based on the downstream temperature data, enabling flow from reservoir 306, reservoir 308, or a combination thereof, so that a target temperature value for the coolant fluid 66 is achieved downstream of valve 302 before distribution by port 68 on arm 102.

[0051]

[0055] Several embodiments of the temperature control system 100 can control multiple polishing stations, each including a platen 24 having an independent temperature control arm 102, a head 70, and a polishing pad 30. Figure 4 shows a polishing system 421 having two polishing stations 401 and 407. Each polishing station 401 and 407 includes a platen 424, 424' supporting a polishing pad 430, 430', and temperature control arms 420, 420' supporting a quenching dispenser 440, 440' having respective ports 467, 467' for distributing coolant liquid 460. Each polishing station 401 and 407 is connected to their respective coolant management systems 410 and 410', which include their respective reservoirs 404 and 404'.

[0052]

[0056] Reservoirs 404 and 404' contain coolant, and the temperature of the coolant is controlled by a connected temperature controller 412. The temperature controller 412 controls temperature control elements 414 and 414' to cool the coolant 460 in reservoirs 404 or 404', respectively. The temperature controller 412 is connected to temperature sensors 405 and 405', which are configured to generate temperature data from reservoirs 404 and 404' regarding the temperature of the coolant 460 stored in reservoirs 404 and 404', respectively. The temperature controller 412 receives the temperature data and controls the temperature control elements 414 and 414' to achieve a desired temperature for the coolant 460.

[0053]

[0057] Coolant management systems 410 and 410' each have two three-way valves. Coolant management system 410 includes three-way valves 402 and 403, and coolant management system 410' includes three-way valves 402' and 403'. The inlets of three-way valves 402 and 402' are fluidly connected to a coolant source 466, such as in the embodiment described with respect to the coolant source 266.

[0054]

[0058] The outlets of the three-way valves 402 and 402' are fluid-connected to the inlets of reservoirs 404 and 404' and three-way valves 403 and 403'. Valves 402 and 402' can each supply coolant liquid 460 from source 466 to either reservoir 404 or 404' for cooling, or, in situations where uncooled liquid 460 is supplied from source 466 before being guided to ports 467 and 467', they can supply it directly to valves 403 and 403'.

[0055]

[0059] In some embodiments, system 421 has a common coolant management system instead of the coolant management systems 410 and 410'. In one such embodiment, the common coolant management system has one reservoir 404, one temperature sensor 405, and one temperature control element 414 connected to one temperature controller 412. The common coolant management system may have any number of three-way valves 403 to distribute the coolant fluid to the respective polishing stations 401 and 407.

[0056]

[0060] Numerous embodiments have been described. Nevertheless, it will be understood that various modifications are possible. Therefore, other embodiments are included in the following claims.

Claims

1. A chemical mechanical polishing apparatus, A platen that holds the polishing pad, A carrier that contacts the polishing surface of the polishing pad and holds the substrate during the polishing process, A polishing liquid dispenser positioned on the platen and having a polishing liquid port for supplying polishing liquid onto the polishing pad, A temperature control system, One or more coolant reservoirs for containing one or more coolant fluids, A temperature controller configured to control the temperature of the coolant in the one or more coolant reservoirs, A first dispenser having a plurality of openings fluidly connected to one or more coolant reservoirs, wherein the plurality of openings are positioned above the platen and configured to spray aerosolized coolant directly onto the polishing pad, A second dispenser having a coolant port fluid-connected to one or more coolant reservoirs, wherein the coolant port is positioned above the platen and configured to direct the flow of coolant directly onto the polishing pad, and A temperature control system including A chemical mechanical polishing apparatus equipped with the following features.

2. The apparatus according to claim 1, further comprising a temperature control arm extending over the platen, wherein one or more openings are formed in a nozzle fixed to the temperature control arm.

3. The apparatus according to claim 2, wherein the coolant port is fixed to the temperature control arm.

4. The apparatus according to claim 2, wherein the coolant ports are fixed to separate temperature control arms.

5. The apparatus according to claim 4, comprising a polishing fluid arm extending over the platen, wherein the coolant port and the polishing fluid port are located on the polishing fluid arm.

6. The apparatus according to claim 1, wherein the temperature controller includes a temperature sensor and a temperature control element, and is configured to receive a temperature value indicating the temperature of the coolant liquid from the temperature sensor, and to control the temperature control element to cool the coolant liquid to less than 5°C based on the received temperature value.

7. The apparatus according to claim 1, wherein one or more coolant reservoirs include a first coolant reservoir connected to the plurality of openings of the first dispenser and a second coolant reservoir connected to the port of the second dispenser.

8. The apparatus according to claim 7, wherein the second coolant reservoir is configured to hold less coolant than the first coolant reservoir.

9. The apparatus according to claim 7, wherein the first coolant reservoir and the second coolant reservoir hold coolant having the same composition.

10. The apparatus according to claim 9, wherein the coolant liquid is deionized water.

11. The apparatus according to claim 7, wherein the temperature control system is configured to control both the first coolant reservoir and the second coolant reservoir to different temperature values, the temperature value of the second coolant reservoir being lower than the temperature value of the first coolant reservoir.

12. The apparatus according to claim 1, wherein one or more coolant reservoirs include a common coolant reservoir connected to the plurality of openings of the first dispenser and the port of the second dispenser.

13. The apparatus according to claim 1, wherein the temperature control system is configured to distribute less than 1 L of fluid through the second dispenser to lower the temperature of the polishing pad by at least 10°C.

14. The apparatus according to claim 1, further comprising a controller configured to spray the aerosolized coolant liquid onto the polishing pad from the first dispenser during a polishing step in which the substrate is polished on the polishing pad, and to cause the flow of the coolant liquid onto the polishing pad from the second dispenser when transitioning from the first polishing step to the second polishing step.

15. The apparatus according to claim 14, wherein the controller is configured to receive a temperature measurement from a sensor during the polishing step and to control the first dispenser to spray the aerosolized coolant liquid to bring the measured temperature to a desired temperature.

16. The apparatus according to claim 14, wherein the controller is configured to receive a signal indicating that the remaining amount of material to be polished is below a threshold, and in response to the signal, to control the second dispenser to flow the coolant liquid onto the polishing pad.

17. The apparatus according to claim 1, further comprising a pad rinsing system including a nozzle for introducing a rinsing medium onto the polishing pad.

18. A chemical mechanical polishing system, There are two polishing stations, and each station is, A platen that holds the polishing pad, A carrier that contacts the polishing surface of the polishing pad and holds the substrate during the polishing process, A polishing liquid dispenser positioned on the platen and having a polishing liquid port for supplying polishing liquid onto the polishing pad, A coolant dispenser positioned on the platen and having a coolant port for supplying coolant liquid onto the polishing pad, Including two polishing stations, A temperature control system, A coolant reservoir for containing coolant, configured to supply the coolant to each coolant port of each polishing station, A temperature controller configured to control the temperature of the coolant in the coolant reservoir. A temperature control system including A chemical mechanical polishing system equipped with the following features.

19. A method for controlling a chemical mechanical polishing process, In a polishing process that includes at least a bulk removal step and a clearing step, the substrate is polished on the surface of the polishing pad, Determining the desired temperature for the bulk removal step, During the bulk removal step, coolant liquid is sprayed onto the polishing pad to bring it to the desired temperature. To detect the transition from the bulk removal step to the clearing step, In response to the detection of a transition from the bulk removal step to the clearing step, the coolant liquid is distributed and flowed onto the surface to lower the temperature of the polishing pad. Methods that include...

20. The method according to claim 19, further comprising controlling the temperature of the coolant liquid to less than 5°C during the polishing process.

Images