Chemical mechanical polishing temperature scanning device for temperature control

Abstract

The present invention provides a chemical mechanical polishing apparatus that improves the predictability of polishing during the polishing process and enhances uniformity within the wafer. [Solution] The chemical mechanical polishing apparatus includes a platen 24 having an upper surface for holding a polishing pad 30, a carrier head 70 for holding a substrate 10 against the polishing surface 36 of the polishing pad 30 during the polishing process, and a temperature monitoring system. The temperature monitoring system 100 includes a non-contact thermal sensor 180 positioned above the platen 24, which has a field of view of a portion of the polishing pad 30 on the platen 24. The sensor 180 is rotatable around a rotation axis 165 by a motor to move its field of view across the polishing pad 30.

Description

Technical Field

[0001] The present disclosure relates to chemical mechanical polishing (CMP), and more particularly to temperature control during chemical mechanical polishing.

Background Art

[0002] Integrated circuits are typically formed on a substrate by sequentially depositing conductive, semiconductor, or insulating layers on a semiconductor wafer. Various manufacturing processes require planarization of the layers on the substrate. For example, one manufacturing step includes depositing a filler layer on a non-planar surface and planarizing the filler layer. In 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 trenches and holes in the insulating layer. After planarization, the remaining portions of the metal in the trenches and holes of the patterned layer form vias, plugs, and lines to provide conductive paths between thin film circuits on the substrate. As another example, a dielectric layer can be deposited on a patterned conductive layer and then planarized to enable subsequent photolithography steps.

[0003] Chemical mechanical polishing (CMP) is an accepted method of planarization. In this planarization method, it is usually necessary to attach the substrate 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 to press the substrate against the polishing pad. A polishing slurry containing polishing particles is typically supplied to the surface of the polishing pad.

Summary of the Invention

[0004] In one embodiment, the chemical mechanical polishing apparatus includes a platen having an upper surface for holding a polishing pad, a carrier head for holding a substrate against the polishing surface of the polishing pad during the polishing process, and a temperature monitoring system. The temperature monitoring system includes a non-contact thermal sensor positioned above the platen, having a field of view of a portion of the polishing pad on the platen. The sensor is rotatable around a rotation axis by a motor to move its field of view across the polishing pad.

[0005] Any embodiment of the above-described aspects may include one or more of the following features:

[0006] The thermal sensor may be rotatable around an axis parallel to the polishing surface.

[0007] A rotatable sensor support can be connected to a motor such that the rotation of the support by the motor rotates the sensor. The sensor support may include an arm extending above the polishing pad. The sensor support may be rotatable around its longitudinal axis. The thermal sensor may be rotatable around an axis perpendicular to the longitudinal axis of the support. The thermal sensor may be movable along the support.

[0008] The temperature monitoring system can be configured to measure the temperature of a portion of the polishing pad.

[0009] The controller can be connected to the motor and a temperature monitoring system. The controller can be configured to control the motor so that a thermal sensor takes measurements at multiple locations on the polishing pad.

[0010] The controller can be configured to generate a temperature profile of the polishing pad based on measurements at multiple locations on the polishing pad. The chemical mechanical polishing apparatus may include a heater and / or cooler. The controller can be configured to adjust the operation of the heater and / or cooler based on the temperature profile to improve the temperature uniformity of the polishing pad. The temperature profile may be a radial profile. The temperature profile may be an angular profile around the rotation axis of the platen. The temperature profile may be a 2D profile.

[0011] The thermal sensor can be positioned above the platen's axis of rotation. The thermal sensor's axis of rotation may be parallel to the platen's axis of rotation. The thermal sensor's axis of rotation may be parallel to the polishing surface.

[0012] In another embodiment, a method for monitoring the temperature of a polishing pad in a chemical mechanical polishing system includes rotating a thermal sensor around a rotation axis such that the thermal sensor remains stationary laterally and the field of view of the thermal sensor sweeps across the polishing surface of the chemical mechanical polishing pad, and using the thermal sensor to take multiple measurements and generate a temperature profile while the field of view is sweeping across the polishing pad.

[0013] Any embodiment of the above-described aspects may include one or more of the following features:

[0014] The axis of rotation may be parallel to the polishing surface.

[0015] The axis of rotation can be perpendicular to the polishing surface.

[0016] Possible benefits include, but are not limited to, one or more of the following: Temperature changes and fluctuations across the polishing pad can be monitored without requiring lateral movement of the thermal sensor. This enables monitoring in crowded polishing stations or provides space for additional components within the polishing station. Furthermore, temperatures at multiple radial locations on the polishing pad can be monitored without contact with the pad. The controller can use the measured temperatures to reduce temperature fluctuations during the polishing process. This improves the predictability of polishing during the polishing process and enhances uniformity within the wafer. [Brief explanation of the drawing]

[0017] [Figure 1A] This is a schematic cross-sectional view of an exemplary polishing apparatus. [Figure 1B] Figure 1A is a schematic top view of an exemplary polishing apparatus. [Figure 2A] This is a schematic cross-sectional view of an exemplary polishing apparatus. [Figure 2B] Figure 2A is a schematic top view of an exemplary polishing apparatus. [Modes for carrying out the invention]

[0018] Chemical mechanical polishing operates through a combination of mechanical wear and chemical etching at the interface between the substrate, polishing fluid, and polishing pad. During the polishing process, a considerable amount of heat is generated due to friction between the substrate surface and the polishing pad. Furthermore, some processes also include an in-situ pad conditioning step, in which a conditioning disc (e.g., a disc coated with polishing diamond particles) is pressed against a rotating polishing pad to condition and texture the surface of the polishing pad. The wear during the conditioning process can also generate heat. 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 a polyurethane polishing pad can rise by approximately 30°C.

[0019] Both the chemical variables (e.g., the initiation and rate of the reactions involved) and the mechanical variables (e.g., the surface friction coefficient and viscoelasticity of the polishing pad) of the CMP process are highly temperature-dependent. Consequently, variations 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 that measured by non-uniformity within or between wafers) can be improved.

[0020] To more precisely control the surface temperature of the polishing pad during polishing and reduce temperature fluctuations, it is desirable to monitor the surface temperature of the polishing pad. Temperature monitoring can be performed using a thermal sensor, and a temperature profile of the polishing pad (e.g., a radial temperature profile) can be generated from temperature readings at various different parts of the polishing pad performed by the thermal sensor.

[0021] Furthermore, the placement of a thermal sensor adjacent to the polishing pad may be impractical due to the number of physical components (e.g., carrier head, slurry dispenser, temperature control system, etc.) that are positioned in contact with the polishing pad and need to move relative to it. However, instead of a thermal sensor configured to sweep across the polishing pad, the thermal sensor may be capable of rotating from a fixed lateral position to sweep its field of view across the polishing pad. Such a configuration can occupy less space and is easier to operate in the presence of other equipment above the polishing pad, such as the carrier head and slurry distribution arm.

[0022] Figures 1A and 1B illustrate an example of a polishing station 20 of a chemical mechanical polishing system. The polishing station 20 includes a rotatable disk-shaped platen 24 with a polishing pad 30 disposed thereon. 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 can be a two-layer polishing pad having an outer polishing layer 34 and a softer backing layer 32.

[0023] The polishing station 20 can include a supply port, for example at an end of a slurry supply arm 39, for dispensing a polishing fluid 38, such as a polishing slurry, onto the polishing pad 30. The polishing station 20 can include a pad conditioner device 90 with a conditioning disk 92 (see FIG. 2) to maintain the surface roughness of the polishing pad 30. The conditioning disk 90 can be disposed at an end of an arm 94 that can swing to sweep the disk 90 radially across the polishing pad 30.

[0024] The carrier head 70 is operable to hold the substrate 10 against the polishing pad 30. The carrier head 70 is suspended from a support structure 72 (e.g., a carousel or a track) and is connected by a drive shaft 74 to a carrier head rotation motor 76 so as to be able to rotate about 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.

[0025] The carrier head 70 can include a retaining ring 84 for holding the substrate. In some embodiments, the retaining ring 84 can include a lower plastic portion 86 that contacts the polishing pad and an upper portion 88 of a harder material.

[0026] During operation, the platen is rotated about its central axis 25, the carrier head is rotated about its central axis 71, and is translated laterally across the upper surface of the polishing pad 30.

[0027] The carrier head 70 can include a flexible film 80 having a substrate mounting surface for contacting the back side of the substrate 10 and a plurality of pressurizable chambers 82 for applying different pressures to different zones (e.g., different radial zones) on the substrate 10. The carrier head can also include a retaining ring 84 for holding the substrate.

[0028] 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 can include a cooling system 102 and / or a heating system 104. At least one of, and in some embodiments both, the cooling system 102 and the heating system 104 operate by delivering a temperature-controlled medium (e.g., liquid, vapor or spray) onto the polishing surface 36 of the polishing pad 30 (or onto the polishing liquid already present on the polishing pad). Alternatively, at least one of, and in some embodiments both, the cooling system 102 and the heating system 104 operate by using a temperature-controlled plate that contacts the polishing pad to change the temperature of the polishing pad by conduction. For example, the heating system 104 can use a hot plate, e.g., a plate with resistive heating or a plate with channels carrying a heating liquid. For example, the cooling system 102 can use a cold plate, e.g., a thermoelectric plate or a plate with channels carrying a coolant liquid.

[0029] As shown in Figures 1A and 1B, the exemplary cooling system 102 includes an arm 110 that extends above the platen 24 and polishing pad 30 from the edge of the polishing pad to the center of the polishing pad 30, or at least near the center. 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 and lowering the arm 110, and / or a rotary actuator for swinging the arm 110 laterally above the platen 24. The arm 110 is positioned to avoid collisions with other hardware components such as the polishing head 70, the slurry distribution arm 39, and the temperature monitoring system 150 (described below).

[0030] 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.

[0031] Each nozzle 120 can be configured to direct the aerosolized water in the spray 122 towards the polishing pad 30. The cooling system 102 may include a liquid cooling medium source 130 and a gas source 132 (see Figure 1B). The liquid from source 130 and the gas from source 132 can be mixed in a mixing chamber 134 (see Figure 1A) (for example, in or on the arm 110) and then directed through the nozzles 120 to form the spray 122.

[0032] In some embodiments, process parameters, such as flow rate, pressure, temperature, and / or liquid-to-gas mixing ratio, can be controlled independently for each nozzle. For example, the coolant for each nozzle 120 may flow through an independently controllable cooling device to independently control the spray temperature. As another example, a separate pair of pumps, one for gas and one for liquid, can be connected to each nozzle to allow independent control of the gas-liquid flow rate, pressure, and mixing ratio for each nozzle.

[0033] In the case of heating system 104, the heating medium may be a gas (e.g., steam or heated air), a liquid (e.g., heated water), or a combination of gas and liquid. The medium is above room temperature, for example, 40–120°C, or for example, 90–110°C. The medium may be water, such as substantially pure deionized water, or water containing additives or chemicals. In some embodiments, heating system 104 uses steam atomization. The steam may contain additives or chemicals.

[0034] The heating medium can be delivered by flowing through openings (e.g., holes or slots) on a heating delivery arm (e.g., provided by one or more nozzles). The openings can be provided by a manifold connected to a source of heating medium.

[0035] An exemplary heating system 104 includes an arm 140 that extends above the platen 24 and polishing pad 30 from the edge of the polishing pad to the center of the polishing pad 30, or at least near the center (e.g., 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, for example, a linear actuator for raising and lowering the arm 140, and / or a rotary actuator for swinging the arm 140 laterally above the platen 24. The arm 140 is positioned to avoid collisions with other hardware components such as the polishing head 70, the pad conditioning disc 92, and the slurry distribution arm 39.

[0036] Multiple openings 144 are formed in the bottom surface of the arm 140. Each opening 144 is configured to direct a gas or vapor (e.g., steam) onto the polishing pad 30. The arm 140 may be supported by a base 142 such that the openings 144 are separated from the polishing pad 30 by gaps. In detail, the gaps may be selected so that the heat of the heating fluid does not dissipate significantly before it reaches the polishing pad. For example, the gaps may be selected so that the steam released from the openings does not condense before it reaches the polishing pad.

[0037] The heating system 104 may include a steam source 146 that can be connected to the arm 140 by a tube. Each opening 144 may be configured to direct steam towards the polishing pad 30.

[0038] In some embodiments, process parameters, such as flow rate, pressure, temperature, and / or liquid-to-gas mixing ratio, can be controlled independently for each nozzle. For example, the fluid from each opening 144 may flow through an independently controllable heater to independently control the temperature of the heating fluid (e.g., the temperature of the steam).

[0039] Figure 1B shows separate arms for each subsystem (e.g., heating system 102, cooling system 104, and rinsing system 106), but various subsystems can also 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 delivery module, and optionally a wiper module. Each module may include a body (e.g., a curved body) that can be fixed to a common mounting plate, which can be fixed to the end of the arm so that the assembly is positioned above the polishing pad 30. Various fluid delivery components (e.g., tubes, passages, etc.) can extend into each body. In some embodiments, the modules are individually detachable from the mounting plate. Each module may have similar components to perform the function of the arm of the associated system described above.

[0040] Referring to Figures 1A and 1B, the polishing station 20 has a temperature monitoring system 150. The temperature monitoring system 100 includes a thermal sensor 180 positioned above the polishing pad 30. The thermal sensor 180 has a field of view 195 of portion 190 of the polishing pad 30. Furthermore, the thermal sensor 180 is movable to change the portion of the pad being monitored. In detail, the thermal sensor 180 may be rotatable to sweep its field of view 195 across various different portions of the polishing pad 30.

[0041] In some embodiments, the thermal sensor 180 is configured to generate a signal with a temperature measurement of the monitored portion 190, for example, the sensor is measuring the collective temperature of that portion. By shifting the field of view 195 of the thermal sensor 180 and taking measurements at multiple locations, the temperature monitoring system 150 can generate a temperature profile of the polishing pad 30. More specifically, by sweeping the field of view 195 of the thermal sensor 180 across the polishing pad 30, the thermal sensor 180 can measure the temperature of various different areas of the polishing pad 30.

[0042] Measurements can be performed on multiple non-overlapping portions of the polishing pad. Alternatively, measurements can be performed on multiple partially overlapping portions. In the latter case, the controller can determine the temperature of a region smaller than the field of view by comparing measurements from multiple adjacent and partially overlapping portions to determine the relative contribution to the temperature from different regions.

[0043] The thermal sensor 180 may be a non-contact sensor such as an infrared sensor, thermal imaging sensor, pyrometer, thermopile detector, pyroelectric detector, or bolometer.

[0044] The portion 190 may have a cross-section (e.g., diameter in the case of a circular portion) of 1 mm to 10 mm. The dimensions of portion 190 may depend on how close the thermal sensor is to the polishing pad 30 (e.g., separation along the z-axis as shown in Figure 1A), the angular spread of the field of view 195 of the thermal sensor 180, and the rotation speed of the platen.

[0045] The thermal sensor 180 may be supported by a sensor support 160. In some embodiments, the sensor support 160 may be an arm that can be positioned above the polishing pad 30. In some embodiments, the sensor support 160 of the thermal sensor 180 may be attached to or provided by other mechanisms of the system 20, such as a support 72.

[0046] As shown in Figures 1A and 1B, the sensor support 160 or the sensor 180 is rotatable around a rotation axis 165 parallel to the upper surface (and polishing surface 36) of the platen 24. This sweeps the field of view 195 of the sensor 180 in a direction perpendicular to the rotation axis 165. For example, an arm functioning as the sensor support 160 may be rotatable by a motor 170, or the sensor 180 may be fixed to the sensor support 160 by an actuator. This allows the thermal sensor 180 to rotate and see different portions 190 at different radial positions on the polishing pad 30. In detail, the field of view can sweep across the polishing pad 30 while the thermal sensor 180 remains stationary laterally.

[0047] Assuming that the sensor support 160 is an arm that rotates around its longitudinal axis, the axis of rotation 165 can be parallel to the longitudinal axis of the arm, and for example, it can be collinear. In this configuration, as the arm rotates, the field of view 195 (and the portion being measured 190) sweeps perpendicular to the longitudinal axis of the arm. In some embodiments, the sensor 180 is positioned on the sensor support 160 such that rotation around axis 165 causes the field of view 195 (and the portion being measured 190) to sweep along the radius of the polishing pad 30 (indicated by arrow C).

[0048] In some embodiments, instead of rotating around axis 165, or in addition to that, the sensor 180 can rotate around a rotation axis 185 that is parallel to the surface of the platen 24 but perpendicular to the arm. This allows the field of view 195 to sweep along the longitudinal axis of the sensor support 160. In this case as well, this allows the sensor 180 to sweep the field of view 195 across the polishing pad 30 and measure the temperature of the polishing pad 30 in the portion 190 that enters the field of view 195.

[0049] In some embodiments, the motor 170 can rotate the sensor support 160 around a vertical rotation axis 175. As the motor 170 rotates the sensor support 160 around the axis 175, the sensor support 160 rotates around the axis 175, and the thermal sensor 180 can translate laterally across the polishing pad. This allows the sensor 180 to see various different parts 190 of the polishing pad 30 while the motor 170 is rotating around the axis 175. For example, if the sensor support 160 is an arm connected to the motor 170, the arm rotates around the axis 175, and the thermal sensor 180 can also rotate around the axis 175.

[0050] In some embodiments, the thermal sensor 180 can move laterally along the sensor support 160. For example, if the sensor support 160 is an arm, the thermal sensor 180 can move along the arm (along the y-axis, as shown in Figure 1A). For example, a linear actuator (e.g., a linear screw drive or rack and pinion gear mechanism) can move the sensor 130 along the sensor support 160.

[0051] As the polishing pad 30 rotates around the axis 25, the thermal sensor 180 can measure the temperature of different parts 190 at various different angular positions on the polishing pad 30. As the polishing pad 30 rotates around the axis 25, areas of the polishing pad 30 that might otherwise be outside the field of view of the thermal sensor 180 can enter the field of view 195 of the thermal sensor 180.

[0052] The controller 90 can be configured to receive measurements from the sensor 180 and operate an actuator to control the position of the monitored portion 190. One or more features of the field of view 195 temperature monitoring system 150. In some embodiments, the controller 90 can cause the actuator to move the sensor support 160 up and down along the z-axis (as shown in Figure 1A), thereby increasing or decreasing the space between the thermal sensor 180 and the polishing pad 30.

[0053] Furthermore, the controller 90 can calculate the distance D from the thermal sensor 180 to the portion 190 on the polishing pad 30 based on the angle of the thermal sensor 180's field of view 195' and the vertical distance from the thermal sensor 180 to the polishing pad 30. Next, the controller 90 can similarly calculate the distance D' from the thermal sensor 180 to the portion 190' on the polishing pad 30 based on the angle of the thermal sensor 180's field of view 195' and the vertical distance from the thermal sensor 180 to the polishing pad 30. Distances D and D' can be used by the controller to compensate for changes in signal intensity due to changes in the distance of the thermal sensor 180 from the portion 190 caused by the rotation of the sensor 180. For example, the thermal radiation reaching the sensor 180 may change according to the inverse square law. The calculated distances can be used to normalize the signal intensity to a standard distance so that the temperature calculation remains accurate even if the distance changes.

[0054] The controller 90 can also determine, based on the angle of the field of view 195, the position of the field of view 195 on the polishing pad 30 with respect to the rotation axis 25, at least radially (and possibly both radially and angularly). This calculation can take into account, for example, the position of the thermal sensor 180 relative to the polishing pad 30, given by the rotation position of the platen 24, the position of the sensor support 160, and the position of the sensor 160 along the sensor support 160. Subsequently, the controller 90 can determine which portion 190' of the polishing pad 30 is being measured and where portion 190' is located relative to portion 190. Using this information, the controller 90 can generate a temperature profile of the polishing pad 30 using the temperature measurement of portion 190 of the polishing pad 30.

[0055] After the thermal sensor 180 measures the temperatures of sections 190 and 190', the controller 90 can combine the measured temperatures of sections 190 and 190' (and so on) to generate a temperature profile of the polishing pad 30. That is, the thermal sensor 180 measures the temperature of section 190, then measures the temperature of section 190', and uses the two sections 190 and 190' to generate a temperature profile (for example, mapping the measured temperatures on the polishing pad 30), taking into account the position of section 190' on the polishing pad 30 relative to the position of section 190 on the polishing pad 30. This process can be repeated to measure the temperatures of further sections of the polishing pad 30 so that a temperature profile of the polishing pad 30 can be generated.

[0056] In some embodiments, the controller 90 uses the temperature profile generated by the temperature monitoring system 150 as feedback to control the temperature control system 100. For example, the temperature control system 100 can determine from the temperature profile generated by the temperature monitoring system 150 that there is a portion 190 of the polishing pad 30 that is not at a desired temperature. The controller 90 can then cause the temperature control system 100 to deliver a temperature-controlled medium onto the portion 190 of the polishing pad 30 to raise or lower the measured temperature to the desired temperature.

[0057] As the thermal sensor 180 moves and sweeps the field of view 195 radially, and the polishing pad 30 rotates around the axis 25, it can generate "spiral" scans of various different parts 190 of the polishing pad 30. This data can provide a radial temperature profile of the polishing pad 30. Alternatively, a collection of multiple circular scans can generate a radial temperature profile of the polishing pad 30.

[0058] Referring to Figures 2A and 2B, the polishing station 20 has a temperature monitoring system 250. The temperature monitoring system 250 is similar to the temperature monitoring system 150 described above, except that a thermal sensor 280 is located in the center above the polishing pad 30. In detail, the thermal sensor 280 can be aligned with the rotation axis 25 of the platen 40. The thermal sensor 280 has a field of view 295 of portion 290 of the polishing pad 30.

[0059] The thermal sensor 280 may be rotatable to sweep its field of view 296 across various different parts of the polishing pad 30.

[0060] The thermal sensor 280 can be supported by a support structure 72 using a sensor support 260. The thermal sensor 280 can be positioned above or substantially above the center of the polishing pad 30. The sensor support 260 or the sensor 280 is rotatable around a rotation axis 265. For example, an arm functioning as the sensor support 260 may be rotatable by a motor 270, or the sensor 280 may be fixed to the sensor support 260 by an actuator. This allows the sensor 280 to rotate and view different portions 290 at different angular positions on the polishing pad 30.

[0061] Assuming the sensor support 260 is an arm that rotates around its longitudinal axis, the axis of rotation 265 is parallel to the longitudinal axis of the arm, and for example, collinear. In some embodiments, the axis of rotation 265 is perpendicular to the polishing surface 36 of the polishing pad 30. The axis of rotation 265 may be parallel to the axis of rotation 25 of the platen.

[0062] In some embodiments, instead of rotating around axis 265, or in addition to that, the sensor 280 can rotate around a rotation axis 285 that is parallel to the top surface of the platen 24 but perpendicular to the arm (and axis 265). This allows the field of view 295 to sweep radially across the polishing pad 30.

[0063] In some embodiments, the thermal sensor 280 can move laterally along the sensor support 260 by moving the sensor support 260 and the thermal sensor 280 laterally along the z-axis (as shown in Figure 2A). This allows the sensor 280 to increase or decrease the distance between the sensor 280 and the polishing pad 30.

[0064] By rotating around axis 265, rotating around axis 285, and / or moving laterally along axis 265, the sensor 280 can first measure the temperature of section 290, then measure the temperature of another section 290', and then generate a temperature profile of the polishing pad 30 that includes multiple temperature measurements of sections 290, 290', etc.

[0065] The temperature profile or temperature map can be used as described above.

[0066] The polishing apparatus and method described above can be applied to 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 may revolve in an orbit rather than rotating. The polishing pad can be a circular (or other shaped) pad fixed to the platen. The polishing layer can be a standard (e.g., polyurethane with or without fillers) abrasive material, a soft material, or a fixed abrasive material.

[0067] The term relative arrangement is used to refer to the relative arrangement within a system or substrate. It should be understood that during the polishing process, the polishing surface and the substrate may be held vertically or in any other orientation.

[0068] The functional operation of the controller 90 can be carried out using one or more computer program products, i.e., one or more computer programs tangibly embodied on a non-temporary computer-readable storage medium for execution by a data processing device (e.g., a programmable processor, a computer, or multiple processors or computers) or for controlling the operation of a data processing device.

[0069] Several embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications can be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

Claims

1. A platen having an upper surface for holding a polishing pad, A carrier head for holding the substrate with respect to the polishing surface of the polishing pad during the polishing process, A temperature monitoring system including a non-contact thermal sensor positioned above the platen so as to have a field of view of a portion of the polishing pad on the platen, the thermal sensor being rotatable around a rotation axis by a motor so as to move the field of view across the polishing pad, A chemical mechanical polishing apparatus equipped with the following features.

2. The apparatus according to claim 1, wherein the thermal sensor is rotatable about an axis parallel to the polished surface.

3. The apparatus according to claim 1, comprising a rotatable sensor support, the sensor support being connected to the motor such that the rotation of the sensor support by the motor causes the sensor to rotate.

4. The apparatus according to claim 3, wherein the sensor support is rotatable about the longitudinal axis of the sensor support.

5. The apparatus according to claim 3, wherein the thermal sensor is rotatable about an axis perpendicular to the longitudinal axis of the sensor support.

6. The apparatus according to claim 3, wherein the thermal sensor is movable along the sensor support.

7. The apparatus according to claim 1, further comprising a controller connected to the motor and the temperature monitoring system, the controller configured to control the motor so that the heat sensor performs measurements at multiple positions on the polishing pad.

8. The apparatus according to claim 7, wherein the controller is configured to generate a temperature profile of the polishing pad based on measurements at the plurality of positions on the polishing pad.

9. The apparatus according to claim 8, further comprising a heater and / or cooler, wherein the controller is configured to adjust the operation of the heater and / or cooler based on the temperature profile to improve the temperature uniformity of the polishing pad.

10. The apparatus according to claim 8, wherein the temperature profile is a radial profile.

11. The apparatus according to claim 8, wherein the temperature profile is an angular profile about the rotation axis of the platen.

12. The apparatus according to claim 8, wherein the temperature profile is a 2D profile.

13. A method for monitoring the temperature of a polishing pad in a chemical mechanical polishing system, Rotating a thermal sensor around a rotation axis, such that the thermal sensor remains stationary in the lateral direction and its field of view sweeps across the polishing surface of a chemical mechanical polishing pad. When the field of view sweeps across the polishing pad, multiple measurements are taken using the thermal sensor to generate a temperature profile. A method that includes this.

14. The method according to claim 13, wherein the axis of rotation is parallel to the polishing surface.

15. The method according to claim 13, wherein the axis of rotation is perpendicular to the polishing surface.

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