Apparatus and method for CMP temperature control

Abstract

The chemical mechanical polishing apparatus includes a rotatable platen that holds a polishing pad, a carrier that holds a substrate against the polishing surface of the polishing pad during the polishing process, and a temperature control system that includes a source of heated or coolant fluid and a plenum positioned above the platen and separated from the polishing pad, the plenum having a plurality of openings that deliver fluid onto the polishing pad, at least some of the openings being configured to deliver different amounts of fluid onto the polishing pad.

Description

[Technical field]

[0001] TECHNICAL FIELD This disclosure relates to chemical mechanical polishing (CMP), and more particularly to temperature control during chemical mechanical polishing. [Background technology]

[0002] Integrated circuits are typically formed on a substrate by sequentially depositing conductive, semiconductive, or insulating layers on a semiconductor wafer. Various manufacturing processes require planarization of layers on the substrate. For example, one manufacturing step involves depositing a filler layer over a non-planar surface and planarizing the filler layer. For certain applications, the filler layer is planarized until the top surface of the patterned layer is exposed. For example, a metal layer can be deposited on a patterned insulating layer to fill the grooves and holes in the insulating layer. After planarization, the remaining portions of the metal within the grooves and holes of the patterned layer form vias, plugs, and lines that provide conductive paths between thin film circuits on the substrate. As another example, a dielectric layer can be deposited on a patterned conductive layer and then planarized to allow for subsequent photolithography steps.

[0003] Chemical mechanical polishing (CMP) is one accepted planarization method. This planarization method typically requires the substrate to be mounted on a carrier head. The exposed surface of the substrate is typically placed against a rotating polishing pad. The carrier head provides a controllable load on the substrate to press it against the polishing pad. A polishing slurry containing abrasive particles is typically supplied to the surface of the polishing pad. Summary of the Invention

[0004] The chemical mechanical polishing apparatus includes a rotatable platen that holds a polishing pad, a carrier that holds a substrate against the polishing surface of the polishing pad during the polishing process, and a temperature control system including a source of heated or coolant fluid and a plenum with multiple openings positioned above the platen and separated from the polishing pad that delivers fluid onto the polishing pad.

[0005] In one aspect, at least some of the openings are each configured to deliver a different amount of fluid onto the polishing pad.

[0006] In another aspect, a first plurality of radial locations along the plenum each have at least two laterally separated openings and a second plurality of radial locations along the plenum each have a single opening.

[0007] In another aspect, the location and size of the openings are such that the mass flow rate of the heated fluid through the plurality of openings increases substantially parabolically with distance from the axis of rotation of the platen.

[0008] In a further aspect, a method of controlling polishing includes measuring a radial temperature profile of a first polishing pad during polishing of a substrate, determining a pattern of openings that provides a mass flow profile that compensates for non-uniformity in the radial temperature profile, obtaining a base plate having openings arranged in the pattern, mounting the base plate within an arm of a temperature control system of a chemical mechanical polishing system to form a plenum with a plurality of openings positioned above a platen, and polishing a substrate using the second polishing pad of the chemical mechanical polishing system while supplying a heated fluid source to the plenum such that heated gas flows through the plurality of openings onto the second polishing pad.

[0009] Implementations may include, but are not limited to, one or more of the following possible advantages: A desired temperature control profile of the polishing pad can be achieved by quickly and efficiently raising and lowering the temperature across the surface of the polishing pad. The temperature of the polishing pad can be controlled without the polishing pad contacting a solid, for example a heat exchange plate, reducing the risk of pad contamination and defects. Temperature variation across a polishing run can be reduced, which can improve the polishing predictability of the polishing process. Temperature variation from polishing run to polishing run can be reduced, which can improve wafer-to-wafer uniformity and improve the repeatability of the polishing process. Temperature variation across the substrate can be reduced, which can improve within-wafer uniformity.

[0010] Plates with different patterns of apertures can be interchanged into the fluid dispenser to provide different temperature profiles, allowing for rapid testing of different temperature profiles or modifications of the polisher for processes that require new temperature profiles.

[0011] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a polishing apparatus. [Diagram 2] FIG. 1 is a schematic top view showing an example of a chemical mechanical polishing apparatus. [Diagram 3] FIG. 2 is a schematic bottom view of the example heat delivery arm of FIG. 1. [Figure 4] FIG. 2 is a graph showing mass flow rate as a function of radial distance from the axis of rotation of the platen of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Like reference numbers in the various drawings refer to like elements.

[0014] Chemical mechanical polishing works by a combination of mechanical polishing and chemical etching at the interface between the substrate, the polishing fluid, and the polishing pad. During the polishing process, a significant amount of heat is generated by friction between the surface of the substrate and the polishing pad. In addition, some processes also include an in-situ pad conditioning step, in which a conditioning disk, e.g., a disk coated with abrasive diamond particles, is pressed against the rotating polishing pad to condition and texture the polishing pad surface. The polishing conditioning process may also generate heat. For example, in a typical copper CMP process with a nominal downforce pressure of 2 psi and a removal rate of 8000 angstroms / min, the surface temperature of a polyurethane polishing pad may increase by about 30°C.

[0015] Both chemically related variables in the CMP process, such as the onset and rate of the reactions involved, and mechanically related variables, such as the surface friction coefficient and viscoelasticity of the polishing pad, are highly temperature dependent. In conclusion, variations in the surface temperature of the polishing pad can lead to changes in removal rate, polishing uniformity, erosion, dishing, and residue. By controlling the temperature of the surface of the polishing pad more closely during polishing, the temperature variations can be reduced, and the polishing performance, as measured by, for example, intra-wafer or inter-wafer non-uniformity, can be improved.

[0016] Several techniques have been proposed for temperature control. As one example, a coolant can be flowed through the platen. As another example, the temperature of the polishing liquid delivered to the polishing pad can be controlled. However, these techniques can be insufficient. For example, the platen must provide or pass heat through the body of the polishing pad itself to control the temperature of the polishing surface. Polishing pads are generally plastic materials and poor thermal conductors, so heat control from the platen can be difficult. On the other hand, the polishing liquid may not have significant thermal mass.

[0017] A technique that can address these challenges is to have a dedicated temperature control system (separate from the polishing liquid supply) that delivers a temperature-controlled medium, such as a liquid, water vapor, or mist, to the polishing surface of the polishing pad (or onto the polishing pad).

[0018] A further challenge is that the temperature rise is often not uniform along the radius of the rotating polishing pad during the CMP process. Without being limited to any particular theory, different sweep profiles of the polishing head and pad conditioner may have different residence times in each radial zone of the polishing pad in some cases. In addition, the relative linear velocity between the polishing pad and the polishing head and / or pad conditioner also varies along the radius of the polishing pad. Furthermore, the polishing liquid may act as a heat sink to cool the polishing pad in the area where the polishing liquid is distributed. These effects may contribute to non-uniform heating on the polishing pad surface, resulting in variations in within-wafer removal rate.

[0019] A technique that can address these challenges is to have a dispenser with fluid flow openings that are spaced and sized to provide a non-uniform mass flow along the radius of the polishing pad. In particular, the pattern of openings along the arm of the dispenser, including the size of the openings and the radial spacing of the openings, can be customized based on the details of the desired temperature control profile.

[0020] 1 and 2 show an example of a polishing station 20 of a chemical mechanical polishing system. The polishing station 20 includes a rotatable, disk-shaped platen 24 on which a polishing pad 30 rests. The platen 24 is operable to rotate about an axis 25 (see arrow A in FIG. 2). For example, a motor 22 can orbit a drive shaft 28 to rotate the platen 24. The polishing pad 30 can be a bi-layer polishing pad having an outer polishing layer 34 and a softer backing layer 32.

[0021] The polishing station 20 may include a feed port 39 that dispenses a polishing liquid 38, such as a polishing slurry, onto the polishing pad 30. Although the exact location of the feed port 39 may vary among different implementations, generally, the feed port 39 is positioned at the end of an arm near the center of the polishing pad 30. For example, the feed port 39 may be positioned at the end of the heated delivery arm 110 (see FIG. 1). As another example, the feed port 39 may be positioned at the end of the slurry feed arm 170 (see FIG. 2). The polishing station 20 may include a pad conditioner device 90 having a conditioning disk 92 (see FIG. 2) to maintain the surface roughness of the polishing pad 30. The conditioning disk 90 may be positioned at the end of an arm 94 that may be rotated to sweep the disk 90 radially across the polishing pad 30.

[0022] Carrier head 70 is operable to hold substrate 10 against polishing pad 30. Carrier head 70 is suspended from a support structure 72, e.g., a carousel or track, and is connected by drive shaft 74 to a carrier head rotation motor 76 such that the carrier head can rotate about axis 71. Optionally, carrier head 70 can be oscillated laterally, e.g., on a slider of the carousel, by movement along the track or by rotational oscillation of the carousel itself.

[0023] The carrier head 70 may include a retaining ring 84 that holds the substrate. In some implementations, the retaining ring 84 may include a lower plastic portion 86 that contacts the polishing pad and an upper portion 88 of a harder material.

[0024] In operation, the platen is rotated about its central axis 25 and the carrier head is rotated about its central axis 71 and translated laterally across the upper surface of the polishing pad 30 .

[0025] Carrier head 70 may include a flexible membrane 80 having a substrate mounting surface that contacts the backside of substrate 10, and a number of pressurizable chambers 82 that apply different pressures to different areas, e.g., different radial areas, on substrate 10. The carrier head may also include a retaining ring 84 that holds the substrate.

[0026] In some implementations, the polishing station 20 includes a temperature sensor 64 that monitors the temperature of the polishing station or of components of the polishing station / within the polishing station, such as the temperature of the polishing pad and / or the slurry on the polishing pad. For example, the temperature sensor 64 can be an infrared (IR) sensor, such as 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 is configured to measure the temperature at multiple points along the radius of the polishing pad 30 to generate a radial temperature profile. For example, the IR camera can have a field of view that spans the radius of the polishing pad 30.

[0027] In some implementations, the temperature sensor is a contact sensor rather than a non-contact sensor. For example, the temperature sensor 64 can be a thermocouple or an IR thermometer positioned on or in the platen 24. Additionally, the temperature sensor 64 can be in direct contact with the polishing pad.

[0028] In some implementations, multiple temperature sensors can be spaced at different radial locations across the polishing pad 30 to provide the temperature at multiple points along the radius of the polishing pad 30. This technique can be used in place of or in addition to an IR camera.

[0029] 1 is positioned to monitor the temperature of the polishing pad 30 and / or the slurry 38 on the pad 30, the temperature sensor 64 can 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 implementations, multiple temperature sensors are included in the polishing station 22, for example, to measure the temperature of different components of / within the polishing station.

[0030] The polishing system 20 also includes a temperature control system 100 that controls the temperature of the polishing pad 30 and / or the slurry 38 on the polishing pad. The temperature control system 100 can include a heating system 102 and / or a cooling system 104. At least one of the cooling system 102 and the heating system 104, and in some implementations both, operate by delivering a temperature-controlled medium, such as a liquid, water vapor, or mist, onto the polishing surface 36 of the polishing pad 30 (or onto polishing fluid already on the polishing pad).

[0031] For the heating system 102, the heating medium can be a gas, e.g., steam or heated air, or a liquid, e.g., heated water, or a combination of gas and liquid. The medium is at a temperature higher than room temperature, e.g., 40-120° C., e.g., 90-110° C. The medium can be substantially pure water, such as deionized water, or water with additives or chemicals. In some implementations, the heating system 102 uses a mist of steam. The steam can include additives or chemicals.

[0032] The heating medium can be delivered to the plenum 116 of the heating delivery arm 110 by flowing it from a source 108, such as a steam generator, through a fluid delivery line 118, which can be provided by piping, flexible tubing, a solid passageway, or some combination thereof.

[0033] An example heating system 102 includes an arm 110 that extends over the platen 24 and polishing pad 30 from the edge of the polishing pad to or at least near the center of the polishing pad 30 (e.g., within 5% of the total radius of the polishing pad). The arm 110 can be supported by a base 112, which can be supported on the same frame 40 as the platen 24. The base 112 can include one or more actuators, such as a linear actuator that raises and lowers the arm 110 and / or a rotary actuator that rotates the arm 110 laterally over the platen 24. The arm 110 is positioned to avoid collisions with other hardware components, such as the polishing head 70 and pad conditioner disk 92.

[0034] A plurality of openings 120 are formed in the bottom surface of the arm 110. Each opening 120 is configured to direct a heated fluid 114, e.g., gas or water vapor, e.g., steam, onto the polishing pad 30. The openings 120 can be provided by holes or slots through the base plate 122. Alternatively, or in addition, some or all of the openings can be provided by nozzles fixed to the bottom of the base plate 122. A center plate 124 can be sandwiched between the base plate 122 and the top plate 126, and an aperture through the center plate 124 can provide the plenum 116. The openings 120 can be small enough and the pressure in the plenum 116 can be high enough so that the heated fluid forms a mist onto the polishing pad 30. The size of the openings can be set, for example, non-adjustable during the polishing operation. For example, the passages can be machined and widened so that the base plate 122 can be removed from the polishing arm and the openings or nozzles can be replaced.

[0035] As described in more detail below with reference to FIG. 3, the plurality of openings 120 are arranged in the bottom surface in a pattern that facilitates effective temperature control of the polishing pad 30 and / or the slurry 38 on the polishing pad according to a desired temperature profile.

[0036] Although FIG. 1 shows equally sized openings 120 positioned along the length of the arm 110 and spaced apart at equal intervals, this is not a requirement. That is, the openings 120 can be unevenly distributed radially or angularly, or both. For example, as shown in FIG. 2, two or more openings 120 can be positioned along the transverse direction of the arm 110. The openings 120 at different radial distances from the center of the platen 24 can be of different sizes, e.g., different diameters, from one another. Furthermore, openings at the same radial distance, i.e., positioned in a line along the transverse direction, can be of different sizes. In addition, although FIGS. 1 and 2 show nine and twelve openings, respectively, there can be more or fewer openings, e.g., between 3 and 200 openings. Furthermore, although FIG. 2 shows circular openings, the openings can be rectangular, e.g., square, elongated slots, or other shapes.

[0037] The various openings 120 can direct different amounts of heated fluid 114, e.g., steam, onto different zones on the polishing pad 30, e.g., onto different radial or angular zones. Adjacent zones may overlap. Optionally, some of the openings 120 can be oriented such that the central axis of the mist from that opening is at an oblique angle to the polishing surface 36. The heated fluid, e.g., steam, can be directed from one or more of the openings 144 to have a horizontal component in a direction opposite to the direction of motion of the polishing pad 30 in the region of impact as caused by rotation of the platen 24.

[0038] The arm 110 can be supported by a base 112 such that the opening 120 is separated from the polishing pad 30 by a gap 130. The gap 130 can be 0.5 to 5 mm. In particular, the gap can be selected such that heat in the heated fluid does not dissipate significantly before the fluid reaches the polishing pad. For example, the gap 130 can be selected such that steam emitted from the opening does not condense before reaching the polishing pad.

[0039] In some implementations, process parameters, such as flow rate, pressure, temperature, and / or liquid to gas mixture ratio, can be independently controlled for different groups of openings 120. This would require the arm to include multiple plenums, with each plenum connected to an independently controllable heater to independently control the temperature of the heated fluid, e.g., vapor temperature, for each plenum.

[0040] For the cooling system 104, the coolant can be a gas, e.g., air, or a liquid, e.g., water. The coolant can be at room temperature or chilled below room temperature, e.g., 5-15°C. In some implementations, the cooling system 104 uses a mist of air and liquid, e.g., an aerosolized mist of liquid, e.g., water. In particular, the cooling system can have a nozzle that generates an aerosolized mist of water chilled below room temperature. In some implementations, a solid material can be mixed with the gas and / or liquid. The solid material can be a chilled material, e.g., ice, or a material that absorbs heat when dissolved in water, e.g., by a chemical reaction.

[0041] The cooling medium can be delivered by flowing through one or more apertures, such as holes or slots, optionally formed in a nozzle in the coolant delivery arm, which can be provided by a manifold connected to a coolant source.

[0042] 2, the example cooling system 104 includes an arm 140 that extends over the platen 24 and polishing pad 30. The arm 140 can be constructed similarly to the arm 110 of the heating system, except as described below.

[0043] Along the rotational direction of the platen 24, the arm 140 of the cooling system 104 can be positioned between the heating arm 110 of the system 110 and the carrier head 70. Along the rotational direction of the platen 24, the arm 140 of the cooling system 104 can be positioned between the arm 110 of the heating system 110 and the slurry delivery arm 170. For example, the arm 110 of the cooling system 110, the arm 140 of the heating system 104, the slurry delivery arm 170, and the carrier head 70 can be positioned along the rotational direction of the platen 24, in that order.

[0044] The exemplary cooling system 102 includes a plurality of openings 144 at the bottom of the arm 140. Each opening 144 is configured to deliver a coolant, e.g., a liquid such as water, or a gas such as air, onto the polishing pad 30. Similar to the openings 120 for the heated fluid, the openings 144 can be arranged on the bottom surface in a pattern that facilitates effective temperature control of the polishing pad 30 and / or the slurry 38 on the polishing pad according to a desired temperature profile.

[0045] The cooling system 102 can include a liquid cooling medium source 146a and / or a gas source 146b (see FIG. 2). In some implementations, the liquid from the medium source 146a and the gas from the gas source 146b can be mixed in a mixing chamber, for example in or on the arm 140, before being directed through the opening 144. For example, the air and gas can be mixed in a plenum.

[0046] The polishing system 20 may also include a controller 90 that controls the operation of various components, such as the temperature control system 100. The controller 90 may be coupled to the heating source 108 and / or the coolant source 146a, 146b to control the flow rate of the heating fluid and / or the coolant. For example, the controller 90 may control the valves or liquid flow controllers (LFCs) of the fluid delivery line 118. The controller 90 may be configured to receive temperature measurements from the temperature sensor 64. The controller 90 may compare the measured temperature to a desired temperature and generate feedback signals to the control mechanisms (e.g., actuators, power supplies, pumps, valves, etc.) for the flow rate of the respective heating and coolant fluids. The feedback signals are used by the controller 90, for example, based on an internal feedback algorithm, to cause the control mechanisms to adjust the amount of cooling or heating so that the polishing pad and / or slurry reach (or at least approach) the desired temperature.

[0047] Although FIG. 2 shows separate arms for each subsystem, e.g., heating system 102, cooling system 104, and rinsing system 106, the various subsystems can be included in a single assembly supported by a common arm. For example, the assembly can include a cooling module, a rinsing module, a heating module, a slurry delivery module, and optionally a wiper module. Each module can include a body, e.g., an arc-shaped body, that can be secured to a common mounting plate, which can be secured at the end of the arm such that the assembly is positioned above the polishing pad 30. Various fluid delivery components, e.g., plenums, piping, passages, etc., can extend inside each body. In some implementations, the modules are separately separable from the mounting plate. Each module can have similar components that perform the functions of the arms of the associated system described above.

[0048] 3 shows a schematic bottom view of an example heated delivery arm 110 of FIG. 1. The arm 110 can be generally straight and have a substantially uniform width along its length, although other shapes such as a circular sector (known as a "pie slice"), a circular arc, or a triangular wedge (all as a bottom view of the system) can be used to achieve the desired effectiveness in controlling the temperature of the polishing pad 30 and / or the slurry 38 thereon. For example, the heated delivery arm 110 can be curved, forming, for example, a circular arc, or a portion of a spiral.

[0049] The heat delivery arm 110 may have a single inlet 119 through which the heating medium enters the plenum 116 of the arm 110. The inlet 119 may be located at a distal end of the arm 110 relative to the axis of rotation of the platen 24.

[0050] The heated delivery arm 110 has a plurality of openings 120 arranged in a pattern on the bottom surface 110a, for example through a base plate 122. The pattern of openings 120 across the bottom surface of the heated delivery arm 110, including the size of the openings and the radial or angular spacing of the openings, can be designed to meet the specific needs of various temperature control profiles. In some cases, the temperature control profile can define the mass flow rate of the heated fluid stream onto the polishing pad as a function of radial distance from the axis of rotation of the platen. For example, the mass flow rate can increase parabolically with distance from the axis of rotation.

[0051] In operation, the platen rotates tangentially to the longitudinal direction of the arm 110. Therefore, for convenience, the longitudinal direction of the arm 110 is also referred to as the radial direction.

[0052] 3, the openings 120 are evenly distributed radially and are more closely packed away from the axis of rotation of the platen, but the openings can be distributed differently to form other patterns. For example, the openings 120 can be unevenly or unevenly spaced along the radial direction. As another example, the openings 120 can be more closely packed along the longitudinal edges of the arm 110.

[0053] At least some of the openings 120 have different sizes and / or shapes and therefore deliver different amounts of heated fluid onto the polishing pad, for example in terms of mass flow rate. In addition, the size distribution of the openings 120 can be weighted more heavily to the larger openings away from the axis of rotation of the platen. As shown, the openings at the distal end of the arm are generally larger than the openings at the end of the arm closer to the axis of rotation of the platen.

[0054] At least some of the openings 120, e.g., openings grouped by tuples 132 or quadruples 134, are laterally separated along the transverse direction of the arm 110. As such, some radial locations along the arm 110 each have at least two laterally separated openings, and some other radial locations along the arm 110 each have a single opening. That is, at least one pair of openings is positioned at the same radial distance from the axis of rotation of the platen.

[0055] 4, as a specific example, a desired temperature control profile, as shown by the solid curve, defines a mass flow rate as a nonlinear, monotonically increasing function of radial distance from the axis of rotation of the platen. More specifically, the openings 120 are arranged to have a parabolic flow rate, which should result in a temperature profile that increases approximately linearly along the radial distance from the axis of rotation of the platen (because area increases parabolically with radius, a larger radial area requires more heated fluid).

[0056] 4 shows a plot including a vertical axis defining mass flow rate in units of kilograms per second (kg / s) and a horizontal axis defining radial distance in terms of how many circumferential rows are spaced from the axis of rotation of the platen. For example, the rows can be equally spaced apart, such as 0.2 to 4 cm, e.g., 0.6 to 1.0 cm.

[0057] By using the heating distribution arm 110 of FIG. 3, the temperature control system 100 can deliver heated fluid at respective mass flow rates that are closely aligned with the solid curve as shown by the scattered dots, thereby effectively controlling the temperature of the polishing pad and / or the slurry on the polishing pad according to a desired temperature control profile.

[0058] To change the distribution of the heating fluid, the arm 110 can be removed and replaced with a new lower plate 112 having a different pattern of openings. In some implementations, the lower plate 112 can be removed from the arm without removing the arm 110 from the base 112. Thus, different plates with different patterns of openings can be used to provide different temperature profiles. This also allows for rapid testing of different temperature profiles or modifications of the polisher for processes that require new temperature profiles.

[0059] For example, the radial temperature profile can be measured while polishing a substrate without temperature control by the arm. A pattern of apertures that provides a mass flow profile that compensates for the non-uniformity of the radial temperature profile is calculated, for example, as the inverse of the radial temperature profile. A base plate with the apertures arranged in a pattern can be manufactured or selected from a set of pre-manufactured base plates. The base plate is then mounted on the arm and used while polishing a substrate.

[0060] The above-mentioned polishing apparatus and method can be applied in various polishing systems. Either the polishing pad or the carrier head, or both, can move to provide relative motion between the polishing surface and the substrate. For example, the platen can orbit rather than rotate. The polishing pad can be a circular (or some other shape) pad fixed to the platen. The polishing layer can be a standard (e.g., polyurethane with or without a filter) polishing material, a soft material, or a fixed abrasive material.

[0061] It should be understood that the term relative positioning is used to refer to relative positioning within the system or substrate, and that the polishing surface and substrate may be held in a vertical orientation or some other orientation during the polishing operation.

[0062] The functional operations of the controller 90 may be realized using one or more computer program products, i.e., one or more computer programs tangibly embodied in a non-transitory computer-readable storage medium, that are executed by or control the operation of a data processing device (e.g., a programmable processor, a computer, or multiple processors or computers).

[0063] A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, while a heated fluid is described above, the arms of a cooling system can be similarly configured, except that a coolant flows through the arms rather than a heated fluid. Similar advantages apply when a cooling system has arms 140 with similar physical structures. For example, the radial profile of the coolant mass flow rate can compensate for temperature non-uniformities, in this case by reducing the temperature rather than increasing it.

[0064] Accordingly, other embodiments are within the scope of the following claims.

Claims

1. a rotatable platen for holding a polishing pad; a carrier head that holds a substrate against the polishing surface of the polishing pad during a polishing process; a slurry supply port for dispensing a polishing slurry onto the polishing pad; a temperature control system including a source of fluid heated to a temperature between 40° C. and 120° C. and an arm extending above the platen and operable to supply the heated fluid onto the polishing pad while the polishing slurry is dispensed onto the polishing pad, the arm having a base plate forming a bottom of the arm, a plurality of openings having a predetermined size extending through the base plate from a common plenum in the arm, the common plenum being coupled to the source of the heated fluid, the arm being positioned such that the openings are separated from the polishing pad by a gap and positioned above the platen to supply the heated fluid from the common plenum onto the polishing pad, at least some of the openings having different sizes each to supply different amounts of the fluid onto the polishing pad; A chemical mechanical polishing apparatus comprising:

2. The apparatus of claim 1 comprising at least one pair of openings positioned the same radial distance from an axis of rotation of the platen.

3. The apparatus of claim 1 , wherein the openings are non-uniformly spaced along a radial distance from an axis of rotation of the platen.

4. The apparatus of claim 3 including a first plurality of radial locations along the plenum, each location of the first plurality of radial locations having at least two laterally separated openings.

5. The apparatus of claim 4 including a second plurality of radial locations along the plenum, each location of the second plurality of radial locations having a single opening.

6. 2. The apparatus of claim 1, wherein the size of the openings and the radial spacing of the openings are such that the mass flow rate of the fluid stream onto the polishing pad is a function of radial distance from an axis of rotation of the platen.

7. The apparatus of claim 6 , wherein the mass flow rate is a non-linear function of radial distance of the platen from the axis of rotation.

8. The apparatus of claim 6 , wherein the mass flow rate is a monotonically increasing function of radial distance of the platen from the axis of rotation.

9. The apparatus of claim 8 , wherein the mass flow rate is a parabolically increasing function of radial distance of the platen from the axis of rotation.

10. The apparatus of claim 1 , wherein the fluid comprises a heated gas.

11. The apparatus of claim 10 , wherein the gas comprises steam.

12. 11. The apparatus of claim 10, wherein the temperature control system includes a coolant source and a second plenum positioned above the platen and separated from the polishing pad, the second plenum having a second plurality of second openings for delivering the coolant onto the polishing pad, at least some of the second openings each configured to deliver a different amount of the coolant onto the polishing pad.

13. a platen for holding a polishing pad; a carrier head that holds a substrate against the polishing surface of the polishing pad during a polishing process; a slurry supply port for dispensing a polishing slurry onto the polishing pad; a temperature control system including a source of fluid heated to a temperature between 40° C. and 120° C. and an arm extending above the platen and operable to supply the heated fluid onto the polishing pad while the polishing slurry is dispensed onto the polishing pad, the arm having a base plate forming a bottom of the arm, a plurality of openings having a predetermined size extending through the base plate from a common plenum in the arm, the common plenum being coupled to the source of the heated fluid, the arm being positioned such that the openings are positioned above the platen through a gap to supply the heated fluid from the common plenum onto the polishing pad, each of a first plurality of radial positions along the common plenum having at least two openings laterally separated, and each of a second plurality of radial positions along the common plenum having a single opening; A chemical mechanical polishing apparatus comprising:

14. 14. The apparatus of claim 13, wherein the temperature control system includes a coolant source and a second plenum positioned above the platen and separated from the polishing pad, the second plenum having a second plurality of openings for delivering the coolant onto the polishing pad, a first plurality of radial positions along the second plenum each having at least two laterally separated second openings, and a second plurality of radial positions along the plenum each having a single second opening.

15. a rotatable platen for holding a polishing pad; a carrier head that holds a substrate against the polishing surface of the polishing pad during a polishing process; a slurry supply port for dispensing a polishing slurry onto the polishing pad; a temperature control system including a source of fluid heated to a temperature between 40° C. and 120° C. and an arm extending above the platen and operable to supply the heated fluid onto the polishing pad while the polishing slurry is dispensed onto the polishing pad, the arm having a base plate forming a bottom of the arm, a plurality of openings having a predetermined size extending through the base plate from a common plenum in the arm, the common plenum being coupled to the source of the heated fluid, the arm being positioned such that the openings are separated from the polishing pad by a gap and positioned above the platen to supply the heated fluid from the common plenum onto the polishing pad, the position and size of the openings being such that a mass flow rate of the heated fluid through the plurality of openings increases substantially parabolically with distance from an axis of rotation of the platen; A chemical mechanical polishing apparatus comprising:

16. Measuring a radial temperature profile of the first polishing pad during polishing of the substrate; determining a pattern of openings that provides a mass flow profile that compensates for non-uniformity in the radial temperature profile; obtaining a base plate having a plurality of openings of a predetermined size arranged in said pattern; placing the base plate within an arm of a temperature control system of a chemical mechanical polishing system such that the plurality of openings form a common plenum positioned above a platen; polishing a substrate using the second polishing pad of the chemical mechanical polishing system while supplying a polishing slurry and a heated fluid to a temperature between 40° C. and 120° C. to the plenum, with the polishing slurry flowing through a slurry supply port and onto the second polishing pad, and with a fluid heated to a temperature between 40° C. and 120° C. flowing through the plurality of openings and onto the second polishing pad; A method for controlling abrasion comprising:

17. The method of claim 16 , wherein obtaining the base plate comprises manufacturing the base plate.

18. The method of claim 16 , wherein obtaining the base plate comprises selecting the base plate from a plurality of pre-manufactured base plates.

19. The apparatus of claim 1 , wherein the lower plate of the base plate is replaceable.

20. The apparatus of claim 1 , wherein the slurry supply port is located in a slurry supply arm or in an arm of the temperature control system.

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