Method for Detecting Incompatible Substrate Processing Targets during Chemical Mechanical Polishing

Abstract

FIELD OF THE DISCLOSURE Embodiments of the present disclosure generally relate to chemical mechanical polishing (CMP) systems and processes used in the manufacture of electronic devices. In particular, embodiments herein relate to a method for detecting non-conforming substrate processing events during a polishing process. In one embodiment, a method for processing a substrate in a polishing system includes pressing a surface of a silicon carbide substrate against a polishing pad in the presence of a polishing fluid, determining the temperature of the polishing pad using a temperature sensor located above the platen, monitoring the temperature of the polishing pad, and initiating a response using a controller of the polishing system when a change in the polishing pad temperature reaches a threshold value.

Description

Technical Field

[0001] The embodiments described herein generally relate to chemical mechanical polishing (CMP) systems and processes used in the manufacture of electronic devices. In particular, the embodiments herein relate to a method for detecting non-conforming substrate processing targets during a polishing process.

Background Art

[0002] Description of Related Art Chemical mechanical polishing (CMP) is commonly used in the manufacture of semiconductor devices to planarize or polish a layer of material deposited on the surface of a crystalline silicon (Si) substrate. In a typical CMP process, a substrate is held by a substrate carrier, and the substrate carrier presses the back side of the substrate against a polishing pad that rotates in the presence of a polishing fluid. Generally, the polishing fluid includes an aqueous solution of one or more chemical components and nanoscale abrasive particles suspended in the aqueous solution. The material is removed across the entire surface of the material layer of the substrate in contact with the polishing pad through a combination of chemical activity and mechanical activity provided by the polishing fluid and the relative movement of the substrate and the polishing pad.

[0003] CMP may also be used in the preparation of silicon carbide (SiC) substrates, which, due to their unique electrical and thermal properties, offer superior performance over Si substrates for advanced high-power and high-frequency semiconductor device applications. For example, CMP may be used to planarize and remove subsurface damage caused by prior grinding and / or lapping operations used in the fabrication of SiC substrates, as well as to prepare the SiC substrates for subsequent epitaxial SiC growth. Typical grinding and / or lapping operations use abrasive particles such as diamond, boron nitride, or boron carbide that are harder than the SiC surface to achieve a reasonable SiC material removal rate from the SiC surface. CMP of SiC, however, typically utilizes abrasive particles having a hardness approximately equal to or less than that of SiC so as not to cause further damage to the SiC substrate surface. Generally, along with the chemically inert nature of the SiC material, one result of the relatively low hardness abrasive particles used in typical SiC CMP processes is that CMP of SiC substrates is a very slow process requiring very long cycle times compared to CMP of material layers, such as dielectric or metal layers, in typical semiconductor device manufacturing processes.

[0004] Once polishing is complete, the SiC substrate may be removed from the polishing system for post-CMP measurement operations, for example, by use of a stand-alone non-contact interferometer system, and then used for post-CMP cleaning and to monitor the performance of the CMP process. Unfortunately, the relatively long cycle times associated with SiC substrate CMP processes, combined with the lack of real-time monitoring of CMP system performance, often result in delays in detecting non-conformance events using post-CMP measurements. Long delays in detecting non-conformance events can result in undesirable rework or loss of substrates to be processed subsequently and a corresponding increase in the associated substrate processing costs.

[0005] Accordingly, what is needed in the present technology is a method for detecting and simultaneously addressing incompatible substrate processing events in CMP processing.

Summary of the Invention

[0006] Embodiments of the present disclosure generally relate to chemical mechanical polishing (CMP) systems and processes used in the manufacture of electronic devices. In particular, embodiments herein relate to methods for detecting incompatible substrate processing events during a polishing process.

[0007] In one embodiment, a method for processing a substrate is provided. The method includes pressing a surface of the substrate against a polishing pad. Here, the polishing pad is disposed on a platen that rotates, and the substrate is disposed on a substrate carrier. Pressing the surface of the substrate against the polishing pad includes applying a downward force on the substrate and rotating the substrate carrier. The method further includes receiving polishing pad temperature information from a temperature sensor. The temperature sensor is installed to measure the polishing pad temperature at a location proximate to a trailing edge of the substrate carrier. The method further includes using the polishing pad temperature information to determine a rate of change of the polishing pad temperature over time, comparing the rate of change of the polishing pad temperature to a predetermined control limit, and communicating a control out-of-limit event to a user. Here, the control out-of-limit event includes the rate of change of the polishing pad temperature that is equal to or outside of the predetermined control limit.

[0008] In another embodiment, a method of polishing a substrate is provided. The method includes pressing a surface of a substrate disposed on a substrate carrier against a polishing pad disposed on a rotating platen. Pressing the surface of the substrate against the polishing pad includes applying a downward force on the substrate and rotating the substrate carrier. The method further includes receiving motor torque information from one or more motor torque sensors. The one or more motor torque sensors are installed to measure platen motor torque and / or substrate carrier motor torque. The method further includes using the motor torque information from the one or more motor torque sensors to determine a rate of change of the motor torque information over time, comparing the rate of change of the motor torque information to a predetermined management limit, and communicating a management deviation event to a user. Here, the management deviation event includes a rate of change of the motor torque information equal to or outside the predetermined management limit.

[0009] In another embodiment, a polishing system is provided. The polishing system includes a rotatable platen, a substrate carrier disposed above the rotatable platen and facing the platen, and a temperature sensor disposed above the rotatable platen. Here, the temperature sensor is installed to measure the polishing pad temperature at a location proximate to the trailing edge of the substrate carrier. The polishing system further includes a computer-readable medium storing instructions related to a substrate processing method. The method includes pressing a surface of a substrate against a polishing pad, receiving polishing pad temperature information from the temperature sensor, using the polishing pad temperature information to determine a rate of change of the polishing pad temperature over time, comparing the rate of change of the polishing pad temperature with a predetermined control limit, and communicating an out-of-control event to a user. Here, the out-of-control event includes a rate of change of the polishing pad temperature equal to or deviating from the predetermined control limit. Typically, the polishing pad is disposed on the rotatable platen, the substrate is disposed on the substrate carrier, and pressing the surface of the substrate against the polishing pad includes applying a downward force on the substrate and rotating the platen and the substrate carrier.

[0010] Therefore, in a manner in which the features described in detail above of the present disclosure can be understood in detail, a more detailed description of the disclosure briefly summarized above may be made by reference to the embodiments illustrated in some of the accompanying drawings. However, it should be noted that the accompanying drawings illustrate only typical embodiments of this disclosure and should not be considered to limit the scope of the disclosure, as the disclosure may admit other equally effective embodiments.

Brief Description of the Drawings

[0011]

Figure 1A

Figure 1B

Figure 1C

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 3C

[0012] For ease of understanding, the same reference numbers are used to indicate the same elements common to multiple figures where possible. It is contemplated that the elements and features of one embodiment may be advantageously incorporated into other embodiments without further recitation.

[0013] Embodiments of the present disclosure generally relate to chemical mechanical polishing (CMP) systems and processes used in the manufacture of electronic devices. In particular, embodiments herein relate to methods for detecting non-conforming substrate events during CMP processing of crystalline silicon carbide (SiC) substrates.

[0014] FIG. 1A is a schematic side view of a polishing station 100 according to one embodiment and may be used to perform the methods described herein. FIG. 1B is a schematic plan view of a multi-station polishing system 101 comprising a plurality of polishing stations 100, where each of the polishing stations 100a-c is substantially similar to the polishing station 100 described in FIG. 1A. In FIG. 1B, at least some of the components related to the polishing station 100 described in FIG. 1A are not shown for the plurality of polishing stations 100 to reduce visual clutter.

[0015] As shown in FIG. 1A, the polishing station 100 includes a platen 102, a first actuator 104 coupled to the platen 102, a polishing pad 106 disposed on and fixed to the platen 102, a fluid supply arm 108 disposed above the polishing pad 106, a substrate carrier 110 (shown in cross-section), and a pad conditioner assembly 112. Here, the substrate carrier 110 is suspended from a carriage arm 113 of a substrate handling carriage 115 such that the substrate carrier 110 is disposed above the polishing pad 106 and faces the polishing pad (FIG. 1B). The substrate handling carriage 115 is used to move the substrate carrier 110, and thus the substrate 122 is chucked to the substrate carrier between the substrate loading station 103 and / or between the polishing stations 100 of the multi-station polishing system 101. In the embodiments herein, an individual one of the polishing stations 100 may further include one or more sensors (e.g., 114, 116, and 118) and may be used to monitor various corresponding process parameters and to perform the methods described herein smoothly.

[0016] During substrate polishing, a first actuator 104 is used to rotate a platen 102 around a platen axis A, and a substrate carrier 110 is disposed above the platen 102 and faces the platen. The substrate carrier 110 is used to simultaneously rotate around a carrier axis B and press a surface of a substrate 122 disposed on the substrate carrier against a polishing surface of a polishing pad 106. The substrate 122 is pressed against the polishing pad 106 in the presence of a polishing fluid supplied by a fluid supply arm 108. Typically, the rotating substrate carrier 110 oscillates between an inner radius and an outer radius of the platen 102 to reduce to some extent non-uniform wear of the surface of the polishing pad 106. Here, the substrate carrier 110 is rotated using a second actuator 124 and oscillated using a third actuator 126.

[0017] Here, the substrate carrier 110 features a carrier head 128, a carrier ring 130 coupled to the carrier head 128, and a flexible film 132 disposed radially inward of the carrier ring 130 to provide an attachment surface for the substrate 122. The flexible film 132 is coupled to the carrier head 128 to define a volume 134 as a whole together with the carrier head 128. During substrate polishing, the carrier ring 130 surrounds the substrate 122 to prevent the substrate 122 from slipping out of the substrate carrier 110. The volume 134 is pressurized such that as the substrate carrier 110 rotates, the flexible film 132 exerts a downward force on the substrate 122, thus pressing the substrate 122 against the polishing pad 106. Before and after polishing, a vacuum is applied to the volume 134 such that the flexible film 132 deflects upward to create a low-pressure pocket between the flexible film 132 and the substrate 122, thus vacuum chucking the substrate 122 to the substrate carrier 110.

[0018] Here, the pad conditioner assembly 112 includes a fixed abrasive conditioning disk 120, such as a diamond-impregnated disk, that may be pressed against the polishing pad 106 to restore the surface of the polishing pad and / or remove polishing by-products or other debris from the polishing pad surface. In other embodiments, the pad conditioner assembly 112 may include a brush (not shown).

[0019] In embodiments herein, one or more sensors include one or a combination of a polishing pad temperature sensor 114, such as an infrared (IR) temperature sensor, a platen torque sensor 116, and a carrier torque sensor 118. Typically, the pad temperature sensor 114 is disposed above the platen 102 and faces the platen. The pad temperature sensor 114 is installed to measure the polishing pad temperature immediately behind the substrate carrier 110 in the direction of platen 102 rotation, i.e., proximate to the trailing edge of the substrate carrier 110. In some embodiments, the pad temperature sensor 114 is coupled to the carriage arm 113.

[0020] Here, the platen torque sensor 116 is connected to the first actuator 104, and the carrier torque sensor 118 is connected to the second actuator 124. In some embodiments, the platen torque sensor 116 and the carrier torque sensor 118 are used to monitor the motor current used to rotate the platen 102 and the substrate carrier 110 about the respective axes A, B of the platen and the substrate carrier.

[0021] Here, the operation of the multi-station polishing system 101 and / or its individual polishing stations 100 is smoothly performed by the system controller 136 (FIG. 1A). The system controller 136 includes a programmable central processing unit (CPU 140) operable with a memory 142 (e.g., non-volatile memory) and support circuits 144. The support circuits 144 are connected to the CPU 140 in a conventional manner and include a cache, a clock circuit, an input / output subsystem, a power supply, etc., and the above combinations connected to various components of the multi-station polishing system 101 to smoothly control the substrate polishing process. For example, in some embodiments, the CPU 140 is in the form of any of a general-purpose computer processor used in an industrial environment, such as a programmable logic controller (PLC) for controlling various polishing system components and sub-processors. The memory 142 connected to the CPU 140 is non-transitory and is typically one or more of readily available memories such as local or remote random access memory (RAM), read-only memory (ROM), floppy disk drive, hard disk, or any other form of digital storage.

[0022] As used herein, the memory 142 is in the form of a computer-readable storage medium (e.g., non-volatile memory) containing instructions that, when executed by the CPU 140, smoothly perform the operation of the multi-station polishing system 101. The instructions in the memory 142 are in the form of a program product (e.g., middleware application, device software application, etc.) such as a program implementing the method of the present disclosure. The program code may conform to any one of a number of different programming languages. In one example, the disclosure may be implemented as a program product stored on a computer-readable storage medium for use in a computer system. The program of the program product defines the functions of the embodiments (including the methods described herein).

[0023] Exemplary computer-readable storage media include, but are not limited to, (i) non-writable storage media in which information is permanently stored (e.g., read-only memory devices in a computer such as a CD-ROM disk readable by a CD-ROM drive, flash memory, ROM chips, or any type of solid-state non-volatile semiconductor memory), and (ii) writable storage media in which changeable information is stored (e.g., a floppy disk in a diskette drive or a hard disk drive or any type of solid-state random access semiconductor memory). Such computer-readable storage media are embodiments of the present disclosure when carrying computer-readable instructions that manage the functions of the methods described herein.

[0024] FIG. 1C illustrates a method 150 for detecting non-conformance events using the polishing pad temperature information received from the pad temperature sensor 114. FIGS. 2A-2B are used herein to illustrate various aspects of the method 150.

[0025] FIG. 2A schematically illustrates the temperature profile from a polishing process 200a for a silicon carbide substrate, where the polishing process starts at time t0 and ends at time t3. Typically from time t0 to time t1, the polishing process is ramped up by increasing the rotational speeds of the platen 102 and the substrate carrier 110 and increasing the downforce used to press the substrate 122 against the polishing pad 106. At time t1, the oscillation of the substrate carrier 110 begins, causing a corresponding oscillation of the polishing pad temperature information 202a. From time t1 to time t2, the polishing pad temperature information 202a rises rather rapidly from an initial temperature T i to a processing temperature T p where the temperature may stabilize for the remainder of the polishing process or may rise gradually from temperature T p T i from T pThe temperature rise up to that point is typically caused by a combination of heat generated by an exothermic reaction with a chemically active component of the polishing fluid of the SiC substrate and the friction between the polishing pad 106 and the substrate 122.

[0026] Generally, for a given set of polishing parameters, the process temperature T p varies depending on any number of factors such as the age of the polishing consumable parts, e.g., the polishing pad 106 and / or the abrasive conditioning disk 120, the surface roughness of the incoming silicon carbide substrate, the stage in a multi-platen polishing process, and / or fluctuations in the polishing fluid flow rate between platens or between substrates polished on individual platens. The variation in the process temperature T p occurring between platens 102 in the multi-station polishing system 101 and / or between substrates polished on individual platens 102 can make the process temperature T p an unreliable indicator for determining whether the polishing process is operating properly. Thus, in the embodiments herein, the method 150 typically monitors the rate of change 206a of the polishing pad temperature information 202a during the polishing process for an indication of whether the polishing process is not operating properly, e.g., an indication of a non-conforming polishing event such as substrate cracking.

[0027] In operation 152, method 150 includes pressing the surface of substrate 122 against polishing pad 106. Here, polishing pad 106 is disposed on platen 102 that rotates, and substrate 122 is disposed on substrate carrier 110. Typically, pressing the surface of substrate 122 against polishing pad 106 includes applying a downward force to substrate 122 and rotating substrate carrier 110. In some embodiments, pressing substrate 122 against polishing pad 106 includes rocking substrate carrier 110 between the inner and outer radii of polishing pad 106. Typically, a SiC substrate polished using method 150 is characterized by a first surface having an Si plane (0001) and a second surface opposite the first surface, with the second surface having a C plane (0001). Method 150 may be used for the polishing process of one or both of the first surface and the second surface, and / or for each polishing stage of a multi-stage polishing process. For example, in some embodiments, polishing the surface of a SiC substrate includes a plurality of polishing stages, each of which is performed using a corresponding individual one of a plurality of polishing stations 100. In some embodiments, the polishing processes are substantially similar at each of the polishing stations 100, e.g., having the same type of polishing pad 106, using the same type of polishing fluid, and / or using substantially similar polishing parameters such as polishing downforce and platen and carrier rotation speeds. In other embodiments, one or more of the polishing stations, e.g., a third polishing station, may be configured differently, e.g., having a different type of polishing pad 106 than the other polishing stations 100 and / or using a different type of polishing fluid. Typically, when the third polishing station is configured differently from the other polishing stations 100, it provides a more refined or gentle polishing process to reduce subsurface damage of the finished SiC substrate. In other embodiments, the first surface may consist of an a-plane (1120), and thus, the second surface consists of an m-plane (1100).

[0028] In operation 154, method 150 includes receiving pad temperature information 202a - 202b from pad temperature sensor 114. Here, pad temperature sensor 114 is installed to measure the polishing pad temperature at a location proximate to the trailing edge of substrate carrier 110, i.e., behind substrate carrier 110 in the direction of rotation of platen 102. The pad temperature is transmitted as pad temperature information 202a - 202b from pad temperature sensor 114 to system controller 136.

[0029] In FIGS. 2A - 2B, the pad temperature information 202a - 202b each generally has a sine wave pattern, and the oscillation of the polishing pad temperature at the measurement location corresponds to the oscillation of substrate carrier 110 between the inner radius and the outer radius of polishing pad 106. In some embodiments, for example, the oscillation period t c of substrate carrier 110 from the inner radius to the outer radius and back to the inner radius is in the range of about 3 seconds to about 20 seconds, such as in the range of about 3 seconds to about 15 seconds, such as in the range of about 3 seconds to about 10 seconds.

[0030] In some embodiments, method 150 further includes processing the pad temperature information 202a - 202b to smooth out local oscillations that could otherwise obscure the rate of change 206a - 206b of the polishing pad temperature over time. For example, in some embodiments, method 150 uses a software - implemented algorithm to approximate the polishing pad temperature over time having a substantially reduced amplitude of the individual oscillations (having period t c ), i.e., to provide the smoothed temperature data 204a - 204b shown in FIGS. 2A - 2B respectively.

[0031] In some embodiments, the algorithm used to generate the smoothed temperature data 204a - 204b uses a moving average to process the polishing pad temperature information 202a - 202b. The moving average is a process of averaging time - series data from a predetermined time window (moving average time window) while moving the time window, for example, averaging the polishing pad temperature information 202a - 202b. Typically, the moving average time window is about 20 seconds or less, such as about 15 seconds or less, about 10 seconds or less, or about 5 seconds or less. In other embodiments, the smoothed temperature data 204a - 204b may be generated using any suitable signal method for reducing the apparent fluctuation or its amplitude of the polishing pad temperature information 202a - 202b.

[0032] In operation 156, method 150 includes determining corresponding rates of change 206a - 206b of the polishing pad over time using the polishing pad temperature information 202a - 202b. Here, the rates of change 206a - 206b of the polishing pad temperature are determined using the derivative values of the smoothed temperature data 204a - 204b at a given time, where the derivative value corresponds to the tangent line to the smoothed temperature data 204a - 204b at that time. In other embodiments, the rates of change 206a - 206b may be determined graphically, for example, by determining the slope of a secant line passing through a first point on the curve formed by the smoothed temperature data 204a - 204b at a first time and a second point proximate to the first point, for example, within 0.5 seconds from the first point.

[0033] In operation 158, method 150 includes comparing the rates of change 206a - 206b of the polishing pad temperature information 202a - 202b with predetermined control limits. The predetermined control limits may be a lower limit, for example, the lower limit X1 shown in FIG. 2B, or an upper limit (not shown). In some embodiments, the rates of change 206a - 206b may be compared with both the control lower limit and the control upper limit. As used herein, rates of change 206a - 206b that are less than the lower limit are "outside the lower limit", and rates of change 206a - 206b that are greater than the upper limit are "outside the upper limit".

[0034] In operation 160, method 150 includes communicating an out-of-control event to a user, where the out-of-control event includes a rate of change 206a-206b of the polishing pad temperature information 202a-202b equal to or outside of a predetermined control limit. Typically, communicating an out-of-control event to a user includes using any form of alarm designated to indicate to a desired user that an out-of-control event has occurred. For example, communicating an out-of-control event to a user may include using visual and audible alarms, and / or sending an electronic message, such as an automatically generated e-mail or an automatically generated text message. In some embodiments, system controller 136 is configured to end and / or interrupt substrate processing operations based on an out-of-control event. In some embodiments, system controller 136 is configured to initiate a change to the polishing process based on an out-of-control event, such as by changing one or more polishing parameters of the polishing process. In some embodiments, system controller 136 is configured to communicate an out-of-control event to a fab-level control system (not shown) connected to system controller 136 via communication. An example of an out-of-control event is illustrated in FIG. 2B.

[0035] FIG. 2B schematically illustrates a temperature profile for a polishing process 200b having an out-of-control event around time t5. Here, the beginning of the temperature profile is similar to the temperature profile shown for polishing process 200a of FIG. 2A. For example, from time t1 to time t2, the polishing pad temperature information 202b rapidly rises from an initial temperature T i to a processing temperature T p where the temperature may stabilize for the remainder of the polishing process or the processing temperature T pIt may gradually increase from . Around time t5, the substrate is broken (cracked), resulting in a relatively rapid decrease in the heat generated by the friction between the substrate surface and the polishing pad 106 and a corresponding decrease in the polishing pad temperature information 202b. The relatively rapid decrease in the polishing pad temperature information 202b is reflected in the change rate 206b that drops below a predetermined management limit X1.

[0036] In FIG. 2B, the method 150 is used to communicate an out-of-control event to the user and to end the polishing process at a time t6 that is before the scheduled substrate processing end time t3 shown in FIG. 2A. By communicating an out-of-control event to the user and / or ending the polishing process, the method 150 advantageously reduces the amount of damage that may be caused to the multi-station polishing system 101 by out-of-spec substrate processing events and / or undesirable rework or loss of subsequently processed substrates. Thus, the method 150 advantageously avoids a corresponding increase in the substrate processing cost associated with out-of-spec substrate processing events. Examples of out-of-spec substrate processing events that can be detected using the method 150 include substrate cracking, interruption or undesirable change in the polishing fluid flow rate, such as clogging of the polishing fluid supply nozzle, processing component failure, such as breakage or rupture of the flexible film 132 of the substrate carrier 110, and / or human error, such as polishing the Si surface or C surface of the substrate when polishing of the already polished SiC substrate surface and / or the opposite surface is desired.

[0037] FIG. 3A is a diagram illustrating a method 350 for detecting an out-of-spec processing event using motor torque information received from one or both of the platen torque sensor 116 and the carrier torque sensor 118. FIGS. 3B - 3C are used herein to illustrate various aspects of the method 350.

[0038] Figures 3B to 3C schematically illustrate the platen torque profiles from a typical polishing process (300b) for a silicon carbide substrate, where the polishing process starts at time t0 and ends at time t3, which is the case of an irregular polishing process (300c) having an incompatible substrate handling event. Here, the platen torque profile includes platen motor torque information 302b to 302c received from the platen torque sensor 116 and the rates of change 306b to 306c of the respective platen motor torque information 302b to 302c.

[0039] In operation 352, method 350 includes pressing the surface of substrate 122 against polishing pad 106. Operation 352 of method 350 may be the same as or substantially similar to operation 152 of method 150 described in FIG. 1C.

[0040] In operation 354, method 350 includes receiving motor torque information 302b to 302c from one or both of platen torque sensor 116 or carrier torque sensor 118.

[0041] In operation 356, method 350 includes using the motor torque information 302b to 302c to determine the corresponding rates of change 306b to 306c of the motor torque information 302b to 302c over time. The rates of change 306b to 306c of the motor torque information 302b to 302c may be determined using any suitable method, such as one or a combination of a plurality of methods used to determine the rates of change 206a to 206b of the polishing pad temperature information 202a to 202b described in operation 156 of method 150.

[0042] In operation 358, method 350 includes comparing the rates of change 306b - 306c of motor torque information 302b - 302c with a predetermined management limit. The predetermined management limit may be a lower limit, for example, the lower limit X2 shown in FIG. 3C, or an upper limit (not shown). In some embodiments, the rates of change 306b - 306c may be compared with both the management lower limit and the management upper limit. As used herein, rates of change 306b - 306c that are smaller than the lower limit are "outside the lower limit", and rates of change 306b - 306c that are larger than the upper limit are "outside the upper limit".

[0043] In operation 360, method 350 includes communicating a management deviation event to the user, where the management deviation event includes a rate of change 306b - 306c of motor torque information 302b - 302c that is equal to or outside of a predetermined management limit. The method of communication may be the same as one or a combination of the plurality of communication methods described in operation 160 of method 150. In some embodiments, method 350 includes ending, interrupting, or starting a change to a substrate processing operation based on the management deviation event.

[0044] FIG. 3C schematically illustrates the platen motor torque for an irregular polishing process 300c having an out-of-control event around time t5. Here, the start of the motor torque profile is similar to the motor torque profile shown for the polishing process 300b in FIG. 3B. For example, from time t1 to time t2, the motor torque information 302c increases rather rapidly as the substrate processing parameters, e.g., the rotation of the platen 102 and the downforce applied to the substrate 122, ramp up. When the desired rotational speed of the platen 102 is reached, the motor torque required to maintain the desired rotational speed generally stabilizes and gradually increases or decreases for the remainder of the typical polishing process (e.g., until time t3 shown in FIG. 3B). In the irregular polishing process 300c shown in FIG. 3C, the substrate is broken (cracked) around time t5, causing a relatively rapid decrease in the friction between the surface of the substrate 122 and the polishing pad 106, and thus resulting in a corresponding decrease in the motor torque required to maintain the set rotational speed of the platen 102. The relatively rapid decrease in the motor torque information 302c is reflected here in the rate of change 306c that drops below a predetermined control limit X2.

[0045] In some embodiments, method 350 is used in combination with method 150 described in FIG. 1C. For example, in such embodiments, both the rate of change of the motor torque information over time and the rate of change of the polishing pad temperature over time are determined and compared to corresponding predetermined control limits. If either is determined to exceed the corresponding control limit, an out-of-control event is communicated to the user.

[0046] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope of the disclosure is determined by the following claims.

Claims

1. A method of processing a substrate in a polishing system, comprising: (a) pressing a surface of the substrate against a polishing pad, wherein the substrate is disposed within a substrate carrier, and pressing the surface of the substrate against the polishing pad includes applying a downward force on the substrate and laterally moving the substrate carrier relative to the polishing pad; (b) receiving polishing pad temperature information from a pad temperature sensor, wherein the pad temperature sensor is coupled to a carriage arm that supports and oscillates the substrate carrier and is positioned to measure the polishing pad temperature at a location proximate to a trailing edge of the substrate carrier; (c) using the polishing pad temperature information to determine a rate of change of the polishing pad temperature over time; (d) comparing the rate of change of the polishing pad temperature to a predetermined management limit; (e) communicating an out-of-control event to a user, wherein the out-of-control event includes a determination that the rate of change of the polishing pad temperature is equal to or outside of the predetermined management limit; and (f) based on the out-of-control event, performing at least one of interrupting a substrate processing operation and changing a substrate processing operation during substrate processing. A method as described above.

2. The method of claim 1, wherein pressing the surface of the substrate against the polishing pad further includes oscillating the substrate carrier between an inner diameter and an outer diameter of the polishing pad coupled to a rotating platen.

3. The method of claim 2, wherein the oscillation of the substrate carrier is correlated with a corresponding oscillation of the polishing pad temperature information, and the method further includes generating smoothed temperature data from the polishing pad temperature information, wherein an amplitude of the oscillation of the smoothed temperature data is reduced from a corresponding amplitude of the oscillation of the polishing pad temperature information.

4. The method of claim 1, wherein the out-of-control event is caused by breakage of the substrate.

5. The method of claim 1, wherein the rate of change of the polishing pad temperature information is determined using smoothed temperature data.

6. The method according to claim 5, wherein the change rate is further determined by using a gradient of a secant line arranged to pass through a first point at a first time and a second point proximate to the first point at a second time on a curve formed by the smoothed temperature data.

7. The method according to claim 1, wherein the pad temperature sensor is installed to measure the polishing pad temperature at a location proximate to a trailing edge of the substrate carrier in a direction of rotation of the polishing pad coupled to a rotating platen.

8. A rotatable platen; A substrate carrier disposed above the rotatable platen and facing the platen; A temperature sensor disposed above the rotatable platen, coupled to a carriage arm that supports and oscillates the substrate carrier, and installed to measure the polishing pad temperature at a location proximate to a trailing edge of the substrate carrier; A computer-readable medium storing instructions related to a substrate processing method comprising a polishing system, wherein the method comprises: (a) pressing a surface of a substrate against a polishing pad, wherein the polishing pad is disposed on the rotatable platen, the substrate is disposed within the substrate carrier, and pressing the surface of the substrate against the polishing pad includes applying a downward force on the substrate and rotating the rotatable platen and the substrate carrier; (b) receiving polishing pad temperature information from the temperature sensor; (c) using the polishing pad temperature information to determine a rate of change of the polishing pad temperature over time; (d) comparing the rate of change of the polishing pad temperature with a predetermined management limit; (e) communicating an out-of-control event to a user, the out-of-control event including a determination that the rate of change of the polishing pad temperature is equal to or outside the predetermined management limit; (f) based on the out-of-control event, performing at least one of interrupting a substrate processing operation and changing a substrate processing operation during substrate processing including a polishing system.

9. The polishing system according to claim 8, further comprising a system controller configured to interrupt or change the substrate processing operation based on the out-of-control event.

10. The polishing system according to claim 8, wherein the substrate carrier is oscillated between an inner diameter and an outer diameter of the rotatable platen.

11. The oscillation of the substrate carrier is associated with a corresponding oscillation of the polishing pad temperature information, and the method further includes generating smoothed temperature data from the polishing pad temperature information, wherein an amplitude of the oscillation of the smoothed temperature data is reduced from a corresponding amplitude of the oscillation of the polishing pad temperature information. The polishing system according to claim 10.

12. The change rate of the polishing pad temperature information is determined by using a slope of a secant line disposed through a first point at a first time and a second point proximate to the first point at a second time on a curve formed by the smoothed temperature data. The polishing system according to claim 8.

13. A method of polishing a substrate, comprising: (a) pressing a surface of the substrate against a polishing pad, wherein the substrate is disposed within a substrate carrier, and pressing the surface of the substrate against the polishing pad includes applying a downward force on the substrate and moving the substrate carrier laterally with respect to the polishing pad; (b) receiving motor torque information from one or more motor torque sensors; (c) using the motor torque information from the one or more motor torque sensors to determine a rate of change of the motor torque information over time; (d) comparing the rate of change of the motor torque information with a predetermined management limit; (e) communicating a first out-of-control event to a desired user, the first out-of-control event including a determination that the rate of change of the motor torque information is equal to or outside the predetermined management limit; (f) based on the first out-of-control event, performing at least one of interrupting the substrate processing operation and changing the substrate processing operation during substrate processing. (g) Receiving polishing pad temperature information from a pad temperature sensor, wherein the pad temperature sensor is coupled to a carriage arm that supports and oscillates the substrate carrier, and is installed to measure the polishing pad temperature at a location proximate to the trailing edge of the substrate carrier; (h) Using the polishing pad temperature information to determine a rate of change of the polishing pad temperature over time; (i) Comparing the rate of change of the polishing pad temperature with a predetermined control limit; (j) Communicating a second out-of-control event to a user, the second out-of-control event including a determination that the rate of change of the polishing pad temperature is equal to or outside of the predetermined control limit; (k) Based on the second out-of-control event, performing at least one of interrupting a substrate processing operation and changing a substrate processing operation during substrate processing; A method comprising the above.

14. The method according to claim 13, wherein the polishing pad is coupled to a platen driven by a platen motor, and the one or more motor torque sensors include a platen motor torque sensor configured to measure platen motor torque.

15. The method according to claim 13, wherein the one or more motor torque sensors include a substrate carrier motor torque sensor configured to measure substrate carrier motor torque.

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