Systems and methods for determining polymer buildup in chemical treatment chambers

Abstract

A method for monitoring polymer deposition in a chemical treatment chamber in response to the generation of thermal energy during a chemical process, the method comprising: determining a response characteristic in response to the generation of thermal energy, the response characteristic including an operating characteristic associated with a heater, a wall characteristic associated with at least one exterior wall surface of the chemical treatment chamber, or a combination thereof, and correlating the response characteristic to an amount of polymer deposition in the chemical treatment chamber based on a response characteristic-polymer deposition correlation model and an emissivity range for the polymer deposition.

Description

[Technical Field]

[0001] SUMMARY The present disclosure relates to systems and methods for determining polymer buildup in chemical processing chambers, such as semiconductor processing chambers. [Background technology]

[0002] The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

[0003] In various chemical processing environments, operators monitor various components to identify and diagnose potential problems or anomalies related to the environment. For example, during semiconductor processing (e.g., dry etch steps), operators may monitor semiconductor processing chambers for polymer deposition on components such as interior walls, liners, showerheads, and heater surfaces.

[0004] As a more specific example, during a dry etching process, one or more precursor gases are used to generate an etchant. When the dry etching process is repeated multiple times, polymers from the gas combination (e.g., fluorocarbon polymers) can deposit on, for example, the interior walls and / or liners of a semiconductor processing chamber, gradually growing in thickness. Furthermore, when the polymer thickness exceeds a threshold thickness, the polymer deposits can erode and adhere to wafers and other components, resulting in reduced wafer yields, wafer defects due to arcing, or inappropriate changes to the etching process parameters to accommodate the polymer deposits.

[0005] Accordingly, operators may employ various polymer deposition monitoring procedures to detect polymer deposition and / or implement one or more corrective actions to address polymer deposition. For example, operators may control the semiconductor processing environment to supply cleaning / oxidizing gases into the semiconductor processing chamber, initiate a wet cleaning process according to a preventive maintenance schedule, or perform a cleaning cycle after processing each wafer (or a predetermined number of wafers). However, these corrective procedures reduce the efficiency of the semiconductor processing system because they may require operators to open the semiconductor processing chamber, clean the chamber, and then reclose the chamber after the cleaning cycle is complete. Once the semiconductor processing chamber is exposed to the atmosphere, a pumping operation is performed to return the chamber to a base vacuum level, which can be a resource- and time-intensive process, thereby reducing chamber throughput. That is, these corrective actions do not include in-situ detection and mitigation procedures to detect polymer deposition and / or implement corresponding corrective actions.

[0006] These problems (and others) related to detecting polymer buildup and taking corrective action are solved by the present disclosure. Summary of the Invention [Means for solving the problem]

[0007] This section provides an overview of the disclosure and is not an exhaustive disclosure of its entire scope or all of its features.

[0008] The present disclosure provides a method for monitoring polymer deposition in a chemical treatment chamber in response to the generation of thermal energy during a chemical process. The method includes determining a response characteristic in response to the generation of thermal energy, the response characteristic including an operating characteristic associated with a heater, a wall characteristic associated with at least one exterior wall surface of the chemical treatment chamber, or a combination thereof. The method further includes correlating the response characteristic to an amount of polymer deposition in the chemical treatment chamber based on a response characteristic-polymer deposition correlation model and an emissivity range for the polymer deposition.

[0009] The following paragraphs include variations of the above method, which may be implemented individually or in any combination within the scope of this disclosure.

[0010] In one aspect, the method includes acquiring steady-state data, the steady-state data being based on a temperature of the wafer in the chemical processing chamber, a chemical process recipe, or a combination thereof. The method further includes determining whether the chemical process is operating at a steady state based on the steady-state data, and determining a response characteristic in response to determining that the chemical process is operating at a steady state. The operating characteristic is an electrical characteristic of the heater, and the electrical characteristic is a voltage change of the heater when the chemical process is operating at a steady state, a current change of the heater when the chemical process is operating at a steady state, or a combination thereof. The method includes acquiring a steady-state voltage of the heater in response to the chemical process operating at a steady state, and determining an electrical characteristic of the heater based on a difference between the steady-state voltage and a previous steady-state voltage of the heater recorded in a database. The method also includes acquiring a steady-state current of the heater in response to the chemical process operating at a steady state, and determining a current change of the heater based on a difference between the steady-state current and a previous steady-state current of the heater recorded in the database. The wall characteristic is one of a temperature characteristic of the at least one exterior wall surface and a heat flux characteristic of the at least one exterior wall surface. The method also includes, in response to the chemical process operating at a steady state, acquiring a steady-state temperature of the at least one exterior wall surface and determining a temperature characteristic based on a difference between the steady-state temperature and a previous steady-state temperature of the at least one exterior wall surface recorded in the database. The steady-state temperature of the at least one exterior wall surface is acquired from a temperature sensor. The method also includes, in response to the chemical process operating at a steady state, acquiring a steady-state heat flux of the at least one exterior wall surface and determining a heat flux characteristic based on a difference between the steady-state heat flux and a previous steady-state heat flux of the at least one exterior wall surface recorded in the database. The steady-state heat flux of the at least one exterior wall surface is acquired from a heat flux sensor. The method further includes selectively performing a corrective action based on the amount of polymer deposition.The corrective action includes generating a notification based on the amount of polymer deposition, adjusting one or more parameters of the chemical process, or a combination thereof. The chemical process is a semiconductor process, and the chemical treatment chamber is a semiconductor processing chamber.

[0011] The present disclosure also provides a system for monitoring polymer deposition in a chemical treatment chamber. The system includes a heater configured to generate thermal energy during a chemical process; a chemical treatment chamber including a wafer and one or more exterior wall surfaces; and a control system including a chemical process controller, a thermal controller, or a combination thereof. The control system is configured to determine whether the chemical process is operating at a steady state based on steady-state data of the chemical treatment chamber, where the steady-state data is based on the wafer temperature, the chemical process recipe, or a combination thereof. The control system is also configured to determine a response characteristic in response to the chemical process operating at a steady state and the heater generating thermal energy, where the response characteristic includes an operating characteristic associated with the heater, a wall characteristic associated with one or more exterior wall surfaces, or a combination thereof. The control system is further configured to correlate the response characteristic to an amount of polymer deposition in the chemical treatment chamber based on a response characteristic-polymer deposition correlation model and an emissivity range for polymer deposition, and selectively implement corrective action based on the amount of polymer deposition.

[0012] The following paragraphs include variations on the above system, which may be implemented individually or in any combination.

[0013] In one form, the operating characteristic is an electrical characteristic of the heater, the electrical characteristic being a change in heater voltage when the chemical process is operating at a steady state, a change in heater current when the chemical process is operating at a steady state, or a combination thereof. The control system is configured to obtain a steady-state voltage of the heater in response to the chemical process operating at a steady state and determine the electrical characteristic of the heater based on a difference between the steady-state voltage and a previous steady-state voltage of the heater recorded in the database. The control system is also configured to obtain a steady-state current of the heater in response to the chemical process operating at a steady state and determine a change in heater current based on a difference between the steady-state current and a previous steady-state current of the heater recorded in the database. The wall characteristic is one of a temperature characteristic of at least one exterior wall surface and a heat flux characteristic of at least one exterior wall surface. The control system is configured to, in response to the chemical process operating at a steady state, acquire a steady-state temperature of at least one exterior wall surface and determine a temperature characteristic of the at least one exterior wall surface based on a difference between the steady-state temperature and a previous steady-state temperature of the at least one exterior wall surface recorded in a database. The steady-state temperature of the at least one exterior wall surface is acquired from a temperature sensor disposed on the wall. The control system is configured, in response to the chemical process operating at a steady state, to acquire a steady-state heat flux of the at least one exterior wall surface and determine a heat flux characteristic of the at least one exterior wall surface based on a difference between the steady-state heat flux and a previous steady-state heat flux of the at least one exterior wall surface recorded in the database. The steady-state heat flux of the at least one exterior wall surface is acquired from a heat flux sensor disposed on the wall. The corrective action includes generating a notification based on the amount of polymer deposition, adjusting one or more parameters of the chemical process, or a combination thereof. The chemical process is a semiconductor process, and the chemical processing chamber is a semiconductor processing chamber.

[0014] The present disclosure provides a method for monitoring polymer deposition in a chemical treatment chamber. The chemical treatment chamber includes a wafer and one or more exterior wall surfaces. The method includes generating thermal energy during a chemical treatment using a heater and determining, by a control system, whether the chemical treatment is operating at a steady state based on steady-state data of the chemical treatment chamber. The steady-state data may be based on the wafer temperature, the chemical treatment recipe, or a combination thereof. The method further includes determining, by the control system, a response characteristic in response to the heater generating thermal energy when the chemical treatment is operating at a steady state. The response characteristic may include an operating characteristic associated with the heater, a wall characteristic associated with one or more exterior wall surfaces, or a combination thereof. The method further includes correlating the response characteristic to an amount of polymer deposition in the chemical treatment chamber based on a response characteristic-polymer deposition correlation model and an emissivity range for polymer deposition, and selectively executing, by the control system, a corrective action based on the amount of polymer deposition.

[0015] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. [Brief explanation of the drawings]

[0016] In order that the present disclosure may be fully understood, various embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0017] [Figure 1] 1 is an example chemical processing environment in accordance with the teachings of the present disclosure.

[0018] [Figure 2] 1 is an example semiconductor processing environment in accordance with the teachings of the present disclosure.

[0019] [Figure 3] FIG. 1 is a functional block diagram of an example semiconductor processing environment in accordance with the teachings of the present disclosure.

[0020] [Figure 4A] FIG. 1 is a functional block diagram of an example control system according to the teachings of the present disclosure.

[0021] [Figure 4B] FIG. 2 is a functional block diagram of an example corrective action module in accordance with the teachings of the present disclosure.

[0022] [Figure 5A] 1 is a flowchart of an example routine for monitoring polymer deposition in a chemical processing environment in accordance with the teachings of the present disclosure.

[0023] [Figure 5B] 1 is a flowchart of an example routine for monitoring polymer deposition within a semiconductor processing environment in accordance with the teachings of the present disclosure.

[0024] [Figure 6A] 10 is a flowchart of another example routine for monitoring polymer deposition in a chemical processing environment in accordance with the teachings of the present disclosure.

[0025] [Figure 6B] 10 is a flowchart of another example routine for monitoring polymer deposition within a semiconductor processing environment in accordance with the teachings of the present disclosure.

[0026] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. DETAILED DESCRIPTION OF THE INVENTION

[0027] The following description is for illustrative purposes only and is not intended to limit the present disclosure, its application, or uses. It should be noted that throughout the drawings, corresponding reference numerals indicate like or corresponding parts or features.

[0028] 1, an example chemical processing environment 5 is shown, generally including a chemical processing chamber 10 and a chemical processing control system 100. In general, chemical processing environment 5 refers to any type of environment in which one or more chemical processes are carried out, such as, for example, a semiconductor processing environment, a combustion exhaust environment, a reactor vessel, a heat exchanger, an industrial dryer / separator in a water treatment system, a fluid flow environment, etc. As used herein, "fluid" refers to a gas, a liquid, and / or a plasma.

[0029] 2 , a semiconductor processing environment 5-1 (chemical processing environment 5) for performing one or more semiconductor processes (chemical processes) is shown, including a semiconductor processing chamber 10-1 (chemical processing chamber 10), a gas supply system 20, a fluid line thermal control system 30, and a semiconductor processing system control system (SPSCS) 100-1 (chemical processing control system 100). In one embodiment, the gas supply system 20 includes a gas source 22, a gas supply line 24 for supplying process gases from the gas source 22 to the processing chamber 10-1, a gas abatement system 26, and an exhaust line 28 for supplying exhaust gases from the processing chamber 10-1 to the gas abatement system 26. The exhaust gases may include post-processing gases, gas / plasma byproducts, and / or wafer-related waste products. In one embodiment, the process gases used in semiconductor wafer processing may be pyrophoric or corrosive (e.g., fluoride, ammonia, silane, argon, arsine, phosphine, and other gases). In some embodiments, unused process gases (e.g., argon or nitrogen) and unwanted by-products are sent to a gas abatement system 26 where they are purified and neutralized before being released into the environment or sent to a subsequent process. Hereinafter, process gases and exhaust gases may be collectively referred to as "gases."

[0030] In one embodiment, the fluid line thermal control system 30 includes a plurality of fluid line heaters 32 positioned at different locations along the gas supply line 24 and the exhaust line 28 to heat the gas flowing therethrough. In one embodiment, the fluid line heaters 32 are flexible heaters wrapped around the gas supply line 24 and the exhaust line 28 to heat the gas therethrough. Heating the gas supplied from the process chamber 10-1 and delivered to the gas abatement system 26 facilitates semiconductor processes performed within the process chamber 10-1 and exhaust gas treatment within the gas abatement system 26. Additionally, heating the gas reduces the deposition of contaminants on the walls of the gas supply line 24 and the exhaust line 28, thereby reducing blockages within the gas supply line 24 and the exhaust line 28.

[0031] In one form, the fluid line thermal control system 30 includes a plurality of fluid line heater sensors 34 for generating fluid line thermal control system data indicative of the temperature of the fluid line heater 32, the heat flux of the fluid line heater 32, and the electrical characteristics (e.g., voltage, current, power, resistance, voltage change, current change, power change, and / or resistance change, etc.) of the fluid line heater 32. The plurality of fluid line heater sensors 34 may include thermocouples, resistance temperature detectors (RTDs), infrared cameras, current sensors, voltage sensors, etc.

[0032] In one embodiment, multiple fluid line heaters 32 can generate electrical characteristics of the fluid line heaters 32 instead of, or in addition to, one or more fluid line heater sensors 34. For example, the fluid line heaters 32 can be configured as "two-wire" heaters, which include one or more resistive heating elements that function not only as a heating element but also as a sensor that measures the average temperature of the element based on its resistance. In this manner, instead of using a separate sensor and four wires, only two wires are required. More specifically, such two-wire heaters are disclosed in U.S. Pat. No. 7,196,295, entitled "TWO-WIRE LAYERED HEATER SYSTEM," which is commonly owned and incorporated herein by reference in its entirety. In a two-wire thermal control system, the fluid line thermal control system 30 is an adaptive thermal control system that blends heater design with integrated control functionality through a customizable feedback control system incorporating power, resistance, voltage, and current, limiting one or more of these parameters (i.e., power, resistance, voltage, and current) while controlling other parameters. In one form, the controller is configured to monitor at least one of the current, voltage, and power supplied to the resistive heating element to determine the resistance and temperature of the resistive heating element. More specifically, such adaptive thermal control systems and controllers are disclosed in U.S. Pat. No. 10,690,705, entitled "POWER CONVERTER FOR A THERMAL SYSTEM," and U.S. Pat. No. 10,908,195, entitled "SYSTEM AND METHOD FOR CONTROLLING POWER TO A HEATER," both of which are commonly owned and incorporated herein by reference in their entireties.

[0033] In one embodiment, the gas delivery system 20 includes a plurality of fluid line flow sensors 36 positioned proximate (i.e., adjacent to or near) the gas supply lines 24 and exhaust lines 28 to measure fluid line data. For example, the fluid line flow sensors 36 are attached to the exterior and / or interior surfaces of the gas supply lines 24 and exhaust lines 28 to monitor temperature for blockages, heat sinks, hot spots, and other conditions that may contribute to system degradation and downtime. In one embodiment, the fluid line data may include, but is not limited to, gas supply line 24 / exhaust line 28 temperature, gas flow rate and pressure, process gas type, and the like. Accordingly, the fluid line flow sensors 36 may include, but are not limited to, temperature sensors, pressure sensors, anemometers, pressure transducers, flow sensors, gas sensors, and the like.

[0034] In one form, the SPSCS 100-1 is configured to control the operation of the fluid line thermal control system 30 and / or the gas delivery system 20 based on the fluid line thermal control system data generated by the fluid line heater sensor 34 and / or the fluid line data generated by the fluid line flow sensor 36, as well as other process data. An example of a control routine for controlling the operation of the fluid line thermal control system 30 and / or the gas delivery system 20 is disclosed in U.S. Patent Application Serial No. 17 / 306,200, entitled "METHOD OF MONITORING A SURFACE CONDITION OF A COMPONENT," which is owned by the same applicant as the present application and the contents of which are incorporated herein by reference in their entirety.

[0035] In one embodiment, the semiconductor processing chamber 10-1 includes a chamber wall 42 defining an outer wall surface 42A and an inner wall surface 42B, a liner 44, a chamber 46, a wafer 48, one or more outer wall surface sensors 50, and a wafer support pedestal 60. Note that the semiconductor processing chamber 10-1 may include other components (e.g., a lid, a showerhead, etc.) and is not limited to the components shown or described herein. In one embodiment, the liner 44 is disposed on at least a portion of the inner wall surface 42B, and the chamber wall 42 and the liner 44 define the chamber 46. Typically, the wafer 48 is disposed on top of the wafer support pedestal 60 (e.g., an electrostatic chuck) as shown during semiconductor processing.

[0036] In one embodiment, one or more exterior wall surface sensors 50 are disposed on the exterior wall surface 42A (e.g., fixed, mounted, and / or attached to the exterior wall surface 42A) and configured to generate sensor data corresponding to wall characteristics of the exterior wall surface 42A. By way of example, the exterior wall surface sensors 50 may be configured as temperature sensors that generate temperature data associated with the exterior wall surface 42A and / or heat flux sensors that generate heat flux data associated with the exterior wall surface 42A. As described in more detail below, the SPSCS 100-1 is configured to determine the wall characteristics (e.g., temperature characteristics and / or heat flux characteristics) of the exterior wall surface 42A based on the sensor data generated by the one or more exterior wall surface sensors 50. The arrangement and number of the exterior wall surface sensors 50 are not particularly limited, and therefore, various operational representations of the sensor data (e.g., trend, average, median, maximum, minimum, etc.) may be provided to the SPSCS 100-1. Also, while one or more exterior wall surface sensors 50 are illustrated as being positioned on the exterior wall surface 42A, it should be understood that, as a variant, one or more exterior wall surface sensors 50 may be positioned on the interior wall surface 42B.

[0037] In one form, the wafer support pedestal 60 includes one or more pedestal heaters 62 and / or one or more pedestal sensors 64. The one or more pedestal heaters 62 each include one or more resistive heating elements and supply (e.g., increase or decrease) thermal energy to the wafer 48, collectively forming one or more heating zones. The SPSCS 100-1 can independently and selectively control the thermal energy supplied to the wafer 48 based on pedestal sensor data generated by the pedestal sensors 64. This pedestal sensor data may be indicative of the temperature of the one or more pedestal heaters 62 and / or wafer 48, the heat flux of the one or more pedestal heaters 62 and / or wafer 48, electrical characteristics of the one or more pedestal heaters 62 (e.g., voltage, current, power, resistance, voltage change, current change, power change, and / or resistance change), etc. By way of example, pedestal sensors 64 include, but are not limited to, temperature sensors, thermocouples, RTDs, infrared sensors, fiber optic sensors, clamp electrodes, radio frequency (RF) antennas, and other conventional temperature sensing devices. Exemplary pedestal heaters and sensors are disclosed in U.S. Patent No. 11,382,180, entitled "MULTI-ZONE PEDESTAL HEATER HAVING A ROUTING LAYER," and U.S. Patent No. 11,343,879, entitled "MULTI-ZONE PEDESTAL HEATER WITHOUT VIAS," both of which are commonly owned and incorporated herein by reference in their entireties.

[0038] Although the pedestal heater 62 and pedestal sensor 64 are shown as being built into the wafer support pedestal 60, it should be understood that the pedestal heater 62 and / or pedestal sensor 64 may be located external to the wafer support pedestal 60. As a variation, the pedestal itself may not include the pedestal heater 62 if external thermal energy is supplied to the fluid (e.g., gas) via the gas supply line 24 to provide the plasma within the chamber 46. Furthermore, it should be understood that the pedestal sensor 64 may be omitted if a "two-wire" heater built into the wafer support pedestal 60 is used as the pedestal heater 62.

[0039] 2 and 3 , the SPSCS 100-1 is configured to monitor polymer deposition 70 within the chamber 46, such as deposition along the interior wall surface 42B and / or the liner 44. In one embodiment, the SPSCS 100-1 includes a recipe module 105, a thermal controller 110, a response characteristic database 120, and a chemical treatment controller 125. The chemical treatment controller 125 may include a status module 130, a response characteristic module 140, a correlation module 150, a response characteristic-polymer deposition correlation (RCPBC) database 160, a corrective action module 170, and a human-machine interface (HMI) 180. In one embodiment, the components of the SPSCS 100-1 are communicatively coupled using wired and / or wireless communication protocols (e.g., Bluetooth®-type protocols, cellular protocols, Wi-Fi®-type protocols, near field communication (NFC) protocols, ultra-wideband (UWB) protocols, etc.).

[0040] In one aspect, the recipe module 105 is configured to prescribe a chemical process recipe to be executed by the SPSCS 100-1 based on user input received from the HMI 180. As used herein, a "chemical process recipe" refers to one or more predefined parameters of a chemical process. Examples of predefined parameters of a chemical process include, but are not limited to, the type of process routine (e.g., a dry etch routine, a vapor deposition routine, etc.), gas temperature, composition of the process gas / plasma supplied into the semiconductor processing chamber 10-1, and / or one or more setpoint operating characteristics (e.g., setpoint electrical characteristics and / or temperature characteristics) of the fluid line heaters 32 and the pedestal heater 62.

[0041] 3 and 4A, a thermal controller 110 is configured to control the operation of one or more pedestal heaters 62 to generate thermal energy during a semiconductor (chemical) process. In one embodiment, the thermal controller 110 includes a power supply 112, a power conversion system 114, and a heater control module 116. The power supply 112 is configured to provide an input voltage (e.g., 240V, 208V) to the power conversion system 114, for example, via an interlock (not shown), which is activated by the heater control module 116 as a safety mechanism to shut off power from the power supply 112.

[0042] The power conversion system 114 adjusts the input voltage based on the control signal received from the heater control module 116 to produce an output voltage (V OUT) to one or more pedestal heaters 62. In one embodiment, the power conversion system 114 includes multiple power converters configured to provide adjustable power to the resistive heating elements of one or more pedestal heaters 62 based on the control signals. An example of a power conversion system is described in co-pending U.S. application Ser. No. 15 / 624,060, "POWER CONVERTER FOR A THERMAL SYSTEM," filed June 15, 2017, which is owned by the same applicant as the present application and is incorporated herein by reference in its entirety. In this example, each power converter includes a buck converter operated by a heater controller to generate a desired output voltage to one or more heating elements in a given zone. Thus, the power conversion system is operable to provide a customizable amount of power (i.e., desired power) to each of the one or more pedestal heaters 62. It should be apparent that other types of power conversion systems may be used to provide the desired power, and the present disclosure is not limited to the examples shown.

[0043] In one embodiment, the heater control module 116 is configured to generate and provide control signals to the power conversion system 114 based on pedestal sensor data generated by the pedestal sensor 64. As an example, in response to receiving a chemical process recipe from the recipe module 105, the heater control module 116 is configured to generate and provide control signals to adjust the duty cycle of the power conversion system 114 based on the recipe, thereby increasing or decreasing an output voltage applied to the pedestal heater 62. In response to receiving the output voltage, the one or more pedestal heaters 62 are configured to generate thermal energy to control the temperature of the wafer 48, for example, during semiconductor processing. In one embodiment, the heater control module 116 is configured to determine electrical characteristics of the pedestal heater 62 based on the pedestal sensor data generated by the pedestal sensor 64. The heater control module 116 is further configured to store the determined electrical characteristics of the pedestal heater 62 in the response characteristics database 120 along with a corresponding timestamp. As described in further detail below, the chemical treatment controller 125 can determine whether the semiconductor process is operating at steady state based on the data stored in the response characteristic database 120 .

[0044] 3 , the state module 130 acquires steady-state data and determines whether the semiconductor process is operating at a steady state based on the steady-state data. The steady-state data is based on the temperature of the wafer 48 indicated by the pedestal sensor data and / or the chemical process defined by the recipe module 105. In one embodiment, the state module 130 determines whether the semiconductor process is operating at a steady state based on the pedestal heater 62 generating thermal energy. The state module 130 may acquire baseline steady-state data when the inner wall surface 42B of the chamber 46 is clean (e.g., a state with little to no contaminants, such as after a wet cleaning of the inner wall surface 42B or when the chamber 46 is new) and thus has no appreciable amount of polymer buildup 70. As described in further detail below, the response characteristic module 140 may determine a response characteristic based on a comparison of the baseline steady-state data with steady-state data acquired after one or more semiconductor process cycles have been completed.

[0045] For example, the state module 130 obtains a type of chemical process recipe (e.g., a dry etch routine) from the recipe module 105 and determines that the semiconductor process is operating at steady state after a predetermined time has elapsed and the pedestal heater 62 begins generating thermal energy (e.g., ramping up the temperature of the wafer 48) as specified by the chemical process recipe. As another example, the state module 130 determines that the semiconductor process is operating at steady state when the temperature of the wafer 48 stabilizes or converges (as indicated by the pedestal sensor data) around the set temperature specified by the chemical process recipe.

[0046] In one embodiment, the response characteristic module 140 determines a response characteristic of the semiconductor processing environment 5-1 in response to the pedestal heater 62 generating thermal energy and / or the state module 130 determining that the semiconductor process is operating at a steady state. In one embodiment, the response characteristic includes an operating characteristic of the pedestal heater 62 and / or a wall characteristic associated with at least one exterior wall surface 42A of the semiconductor processing chamber 10-1. By way of example, the operating characteristic of the pedestal heater 62 may be an electrical characteristic (e.g., voltage change and / or current change) of the pedestal heater 62, a temperature characteristic (e.g., temperature change) of the pedestal heater 62, a performance characteristic of the pedestal heater 62, or a combination thereof. Furthermore, the wall characteristic of the at least one exterior wall surface 42A may be a temperature characteristic (e.g., temperature change) of the at least one exterior wall surface 42A and / or a heat flux characteristic (e.g., heat flux change) of the at least one exterior wall surface 42A. Additional details regarding the electrical characteristics, temperature characteristics, wall characteristics, and heat flux characteristics are described below.

[0047] As an example, the response characteristic module 140 determines the voltage change of the pedestal heater 62 when the semiconductor process is operating at a steady state. To determine the voltage change of the pedestal heater 62 (the electrical characteristic of the pedestal heater 62), the response characteristic module 140 obtains the steady-state voltage of the pedestal heater 62 from the heater control module 116 and also obtains a previous steady-state voltage (i.e., a steady-state voltage with a previous time stamp) determined by the heater control module 116 and stored in the response characteristic database 120. As an example, the response characteristic module 140 determines the voltage change of the pedestal heater 62 based on the difference / trend between the obtained or measured steady-state voltage and the reference steady-state voltage (i.e., the steady-state voltage when the semiconductor processing chamber 10-1 is clean and free of appreciable polymer deposits 70) stored in the response characteristic database 120. The response characteristic module 140 then determines the voltage change based on the difference / trend between the steady-state voltage and the previous steady-state voltage.

[0048] As another example, the response characteristic module 140 determines the current change of the pedestal heater 62 (the electrical characteristic of the pedestal heater 62) when the semiconductor process is operating at a steady state. To determine the current change of the pedestal heater 62, the response characteristic module 140 obtains the steady-state current of the pedestal heater 62 from the heater control module 116 and also obtains a previous steady-state current (i.e., a steady-state current having a previous timestamp) obtained by the heater control module 116 and stored in the response characteristic database 120. As an example, the response characteristic module 140 determines the current change of the pedestal heater 62 based on the difference / trend between the obtained or measured steady-state current and a reference steady-state current (i.e., a steady-state current when the semiconductor processing chamber 10-1 is clean and free of appreciable polymer deposits 70) stored in the response characteristic database 120. The response characteristic module 140 then determines the current change based on the difference / trend between the steady-state current and the previous steady-state current.

[0049] As yet another example, the response characteristic module 140 determines a temperature characteristic (wall characteristic) of at least one exterior wall surface 42A when one or more exterior wall surface sensors 50 include a temperature sensor. To determine the temperature characteristic of the at least one exterior wall surface 42A, the response characteristic module 140 determines a steady-state temperature of the exterior wall surface 42A (i.e., the temperature of the exterior wall surface 42A when the semiconductor process is in a steady state) based on temperature data generated by the temperature sensor (one or more exterior wall surface sensors 50). Furthermore, the response characteristic module 140 obtains a previous steady-state temperature (i.e., a steady-state temperature with a previous time stamp, e.g., a reference steady-state temperature when the semiconductor processing chamber 10-1 is clean and free of appreciable polymer buildup 70) determined by the response characteristic module 140 and stored in the response characteristic database 120, and determines the temperature characteristic based on the difference / trend between the steady-state temperature and the previous steady-state temperature.

[0050] As a further example, the response characteristic module 140 determines heat flux characteristics (wall characteristics) of at least one exterior wall surface 42A when one or more exterior wall surface sensors 50 include a heat flux sensor. To determine the heat flux characteristics of the at least one exterior wall surface 42A, the response characteristic module 140 determines a steady-state heat flux of the exterior wall surface 42A (i.e., the heat flux of the exterior wall surface 42A when the semiconductor process is in a steady state) based on heat flux data generated by the heat flux sensor (one or more exterior wall surface sensors 50). Furthermore, the response characteristic module 140 obtains a previous steady-state heat flux (i.e., a steady-state heat flux having a previous timestamp, e.g., a reference steady-state heat flux when the semiconductor processing chamber 10-1 is clean and free of appreciable polymer deposits 70) determined by the response characteristic module 140 and stored in the response characteristic database 120, and determines the heat flux characteristics based on the difference / trend between the steady-state heat flux and the previous steady-state heat flux.

[0051] In one embodiment, the correlation module 150 correlates the response characteristic to the quantity (e.g., volume, thickness, and / or shape) of the polymer deposit 70 in the semiconductor processing chamber 10-1 based on a response characteristic-polymer deposit correlation (RCPBC) model and emissivity ranges of the polymer deposit 70 stored in the RCPBC database 160. In one embodiment, the RCPBC model is a table that maps the response characteristic (e.g., the operating characteristics of the pedestal heater 62 and / or wall properties associated with at least one exterior wall surface 42A of the semiconductor processing chamber 10-1) and a known emissivity range (e.g., between 0 and 1, where an emissivity value of 0 corresponds to a perfect reflector and an emissivity value of 1 corresponds to a perfect emitter) of the polymer deposit 70 to the quantity of the polymer deposit 70. The known emissivity range of the polymer deposit 70 may be defined, for example, based on the type of polymer deposit 70. The RCPBC database 160 may store multiple RCPBC models corresponding to various emissivity ranges and types of wall properties.

[0052] As one example, the RCPBC model is an experimentally defined and / or mathematically based model that maps steady-state voltage and / or current changes and known emissivity ranges of the polymer deposits 70 to the amount of polymer deposits 70. As another example, the RCPBC model is an experimentally defined and / or mathematically based model that maps steady-state temperature and / or heat flux changes (wall properties) and known emissivity ranges of the polymer deposits 70 to the amount of polymer deposits 70.

[0053] In one form, the RCPBC model is a machine learning model, such as an artificial neural network model, a convolutional neural network model, and / or other similar machine learning models. Accordingly, correlation module 150 may be configured to perform machine learning routines, such as supervised learning routines, unsupervised learning routines, reinforcement learning routines, self-learning routines, and / or black-box modeling routines, to determine the amount of polymer deposits 70 based on the RCPBC model.

[0054] By way of example, the RCPBC model may be a supervised learning model such as a multiple regression model or a multivariate regression model (e.g., a regression model such as a linear regression model, a logistic regression model, a ridge regression model, a lasso regression model, a polynomial regression model, and / or a Bayesian linear regression model). That is, when correlation module 150 performs a supervised learning routine based on the RCPBC, correlation module 150 may correlate a known emissivity range of the polymer deposit 70 and at least one of a voltage change, a current change, a heat flux change, and a temperature change with the amount of polymer deposit 70. Furthermore, correlation module 150 may iteratively perform this supervised learning routine for different amounts, emissivity ranges, and wall properties of the polymer deposit 70 to improve the accuracy of the RCPBC.

[0055] As another example, the RCPBC model is an unsupervised learning model, such as a clustering model. That is, when the correlation module 150 performs an unsupervised learning routine based on the RCPBC, the correlation module 150 can generate a feature vector having any number of dimensions (e.g., an n-dimensional vector) based on the known emissivity range of the polymer deposit 70 and at least one of voltage change, current change, heat flux change, and temperature change. The correlation module 150 can then group the feature vector into multiple clusters by performing a connectivity-based clustering routine, a self-organizing map (SOM) clustering routine, a centroid-based clustering routine, a density-based clustering routine, or other clustering routine, or a distribution-based clustering routine. The correlation module 150 can then classify the polymer deposit 70 into one or more deposition amount ranges by, for example, performing a dimensionality reduction routine (e.g., a principal component analysis (PCA) routine) to reduce the dimensionality of the clusters to a predetermined number of dimensions with the greatest feature influence and classifying the clusters into one or more polymer deposition amount ranges.

[0056] In one form, the corrective action module 170 is configured to selectively execute corrective actions based on the amount of polymer deposition 70. As an example, the corrective action may include instructing the HMI 180 to generate a notification when the amount of polymer deposition 70 exceeds a threshold. The notification may include information indicating the amount of polymer deposition 70 and operator instructions to address the excessive polymer deposition 70 (e.g., operator instructions to supply a cleaning / oxidizing gas into the semiconductor processing chamber 10-1 or operator instructions to initiate a wet cleaning routine). As another example, the corrective action may include instructing the recipe module 105 to adjust one or more parameters of a semiconductor process recipe, such as gas temperatures and / or one or more setpoint operating characteristics of the fluid line heaters 32 and / or the pedestal heater 62.

[0057] To perform the functions described herein, HMI 180 may be provided by a computing device (e.g., a smartphone, laptop, desktop computing device, programmable logic controller, tablet, etc.) that includes various visual interfaces (e.g., a touchscreen, a display monitor, an augmented reality device, and / or multiple light-emitting diodes (LEDs)), auditory interfaces (e.g., speaker circuitry for audibly outputting messages corresponding to notifications), and / or tactile interfaces (e.g., vibration motor circuitry for selectively vibrating).

[0058] In one embodiment, the corrective action module 170 is configured to perform the corrective action based on the amount of polymer deposition 70 and further based on machine learning routines, such as supervised learning routines, unsupervised learning routines, reinforcement learning routines, self-learning routines, and / or black-box modeling routines, to select an appropriate corrective action. As an example, as shown in FIG. 4B , the corrective action module 170-1 (the corrective action module 170) is configured to perform a reinforcement learning routine to select an appropriate corrective action based on the amount of polymer deposition 70. In one embodiment, the corrective action module 170-1 includes a state vector module 171, a state-corrective action module 172, a reward module 173, an entry generation module 174, a state-corrective action database 175, and a target corrective action module 176. In one embodiment, the state vector module 171 generates a plurality of state vectors, each state vector indicating the amount of polymer deposition 70 at a predetermined discrete time value.

[0059] In one embodiment, the status-corrective action module 172 defines a plurality of corrective actions associated with the status vector. The plurality of corrective actions may include, but are not limited to, directing the gas source 22 to supply a cleaning / oxidizing gas into the semiconductor processing chamber 10-1, directing the gas source 22 to initiate a wet cleaning routine, adjusting the gas temperature, adjusting one or more setpoint operating characteristics of the fluid line heaters 32, adjusting one or more setpoint operating characteristics of the pedestal heater 62, removing power to the pedestal heater 62 via an interlock (not shown), and a status maintenance action. As used herein, a "status maintenance action" refers to not performing a corrective action. In one embodiment, the status-corrective action module 172 defines, for each corrective action type, corrective actions corresponding to various amounts of polymer buildup 70.

[0060] In one form, the reward module 173 is configured to determine a reward for each corrective action using a known reinforcement learning routine (e.g., a Q-learning routine with a learning rate ranging from 0 to 1). The reward value indicates a qualitative and / or quantitative metric related to a predicted change in chamber throughput, efficiency of the semiconductor processing system 5-1, or a combination thereof. By way of example, a larger reward value corresponds to an improvement in the qualitative / quantitative metric related to the resulting chamber throughput and / or efficiency of the semiconductor processing system 5-1, and a smaller reward value corresponds to a deterioration in the qualitative / quantitative metric related to the resulting chamber throughput and / or efficiency of the semiconductor processing system 5-1.

[0061] In one embodiment, entry generation module 174 associates each corrective action generated by condition-corrective action module 172 with a corresponding reward value generated by reward module 173. In one embodiment, entry generation module 174 generates an entry for each condition-corrective action and reward value pair and stores the generated entries in condition-corrective action database 175. In one embodiment, target corrective action module 176, after being sufficiently trained, autonomously selects corrective actions to be taken based on the entries in condition-corrective action database 175 and the associated reward values.

[0062] 5A, a flowchart illustrating a routine 500 for monitoring polymer deposition in a chemical treatment chamber 10 is shown. In step 504, the chemical treatment control system 100 generates thermal energy during a chemical process. In step 508, the chemical treatment control system 100 determines a response characteristic in response to the generation of thermal energy. In step 512, the chemical treatment control system 100 correlates the response characteristic to the amount of polymer deposition in the chemical treatment chamber 10 based on the RCPBC model and the emissivity range of the polymer deposition.

[0063] 5B, a flow chart illustrating a routine 550 for monitoring polymer deposition 70 in semiconductor processing chamber 10-1 is shown. In step 554, SPSCS 100-1 generates thermal energy during semiconductor processing. In step 558, SPSCS 100-1 determines a response characteristic in response to the generation of thermal energy. In step 562, SPSCS 100-1 correlates the response characteristic to the amount of polymer deposition in semiconductor processing chamber 10-1 based on the RCPBC model and the emissivity range of the polymer deposition 70.

[0064] 6A, a flowchart illustrating a routine 600 for monitoring polymer deposition in a chemical treatment chamber 10 is shown. In step 604, the chemical treatment control system 100 generates thermal energy during a chemical process. In step 608, the chemical treatment control system 100 determines whether the chemical process is operating at a steady state based on steady-state data from the chemical treatment chamber 10. If the chemical process is not operating at a steady state, the routine 600 proceeds to step 604. If the chemical process is operating at a steady state in step 608, the routine 600 proceeds to step 612, where the chemical treatment control system 100 determines a response characteristic. In step 616, the chemical treatment control system 100 correlates the response characteristic to the amount of polymer deposition in the chemical treatment chamber based on the RCPBC model and the emissivity range of the polymer deposition. In step 620, the chemical treatment control system 100 selectively implements corrective action based on the amount of polymer deposition.

[0065] Referring to FIG. 6B, a flowchart illustrating a routine 650 for monitoring polymer deposition in semiconductor processing chamber 10-1 is shown. In step 654, SPSCS 100-1 generates thermal energy during a semiconductor process. In step 658, SPSCS 100-1 determines whether the semiconductor process is operating at a steady state based on steady-state data for semiconductor processing chamber 10-1. If the semiconductor process is not operating at a steady state, routine 650 proceeds to step 654. If the semiconductor process is operating at a steady state in step 658, routine 650 proceeds to step 662, where SPSCS 100-1 determines a response characteristic. In step 666, SPSCS 100-1 correlates the response characteristic to the amount of polymer deposition in semiconductor processing chamber 10-1 based on the RCPBC model and the emissivity range of polymer deposition 70. In step 670, SPSCS 100-1 selectively implements corrective action based on the amount of polymer deposition.

[0066] The present disclosure provides a system and method for monitoring polymer deposition in a chemical treatment chamber. A control system generates thermal energy during a chemical process and determines a response characteristic in response to the generation of thermal energy. The response characteristic may include an operating characteristic associated with a heater, a wall characteristic associated with at least one exterior wall surface of the chemical treatment chamber, or a combination thereof. The control system correlates the response characteristic to the amount of polymer deposition in the chemical treatment chamber based on a response characteristic-polymer deposition correlation model and an emissivity range for the polymer deposition. This allows the control system to perform an in-situ monitoring routine that accurately monitors the polymer thickness, thereby improving wafer yield, preventing wafer defects, and preventing inappropriate shifts in a chemical process (e.g., a semiconductor process) to accommodate the polymer deposition. Furthermore, the control system improves the efficiency of the chemical treatment system, for example, in terms of cycle time or the number of wafers produced in a given time period.

[0067] Unless expressly stated otherwise herein, all numerical values ​​expressing mechanical / thermal properties, composition percentages, dimensions and / or tolerances, and other properties, for describing the scope of this disclosure, should be understood to be modified by "about" or "approximately." This modification may be desirable for various reasons, including industrial practices, materials, manufacturing and assembly tolerances, and testing capabilities.

[0068] The expression "at least one of A, B, and C" used in this specification should be interpreted as a logical expression using a non-exclusive logical OR (A OR B OR C), and not as "at least one of A, at least one of B, and at least one of C."

[0069] As used herein, the terms "controller" and / or "module" may refer to or include portions of the following: an application specific integrated circuit (ASIC), digital, analog, or mixed analog / digital discrete circuitry, a digital, analog, or mixed analog / digital integrated circuit, a combinational logic circuit, a field programmable gate array (FPGA), a processor circuit (shared, dedicated, or group) that executes code, a memory circuit (shared, dedicated, or group) that stores code to be executed by the processor circuit, any other suitable hardware component that provides the described functionality, or a combination of some or all of the above, such as a system on a chip.

[0070] The term "memory" is a subset of the term "computer-readable medium." As used herein, the term "computer-readable medium" does not include transitory electrical or electromagnetic signals (e.g., signals on a carrier wave) propagating through a medium. Thus, a "computer-readable medium" is considered to be tangible and non-transitory. Non-limiting examples of non-transitory, tangible computer-readable media include non-volatile memory circuits (such as flash memory circuits, erasable programmable read-only memory circuits, masked read-only circuits, etc.), volatile memory circuits (such as static random access memory circuits and dynamic random access memory circuits), magnetic recording media (such as analog or digital magnetic tape, hard disk drives, etc.), and optical recording media (such as CDs, DVDs, Blu-ray Discs, etc.).

[0071] The apparatus and methods described herein may be implemented, in part or entirely, by a special-purpose computer created by configuring a general-purpose computer to perform one or more specific functions embodied in a computer program. The functional blocks, flowchart components, and other elements described above function as software specifications and can be converted into a computer program by the routine work of a skilled engineer or programmer.

[0072] The description of the present disclosure is merely exemplary, and thus, variations that do not depart from the gist of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.

Claims

1. 1. A method for monitoring polymer deposition in a chemical treatment chamber in response to the production of thermal energy during a chemical process, comprising: determining a response characteristic in response to the generation of thermal energy, the response characteristic comprising an operational characteristic associated with a heater, a wall characteristic associated with at least one exterior wall surface of the chemical treatment chamber, or a combination thereof; correlating the response characteristic to an amount of polymer deposition in the chemical treatment chamber based on a response characteristic-polymer deposition correlation model and an emissivity range for the polymer deposition; A method comprising:

2. acquiring steady-state data based on a wafer temperature in the chemical processing chamber, a chemical process recipe, or a combination thereof; determining whether the chemical process is operating at a steady state based on the steady-state data; determining the response characteristic in response to determining that the chemical process is operating at the steady state; The method of claim 1 further comprising:

3. The method of claim 2 , wherein the operating characteristic is an electrical characteristic of the heater.

4. 4. The method of claim 3, wherein the electrical characteristic is a change in voltage of the heater when the chemical process is operating at the steady state, a change in current of the heater when the chemical process is operating at the steady state, or a combination thereof.

5. obtaining a steady-state voltage of the heater in response to the chemical process operating at the steady-state; determining the electrical characteristic of the heater based on a difference between the steady-state voltage and a previous steady-state voltage of the heater recorded in a database; The method of claim 4 further comprising:

6. obtaining a steady state current of the heater in response to the chemical process operating at the steady state; determining the change in current of the heater based on a difference between the steady state current and a previous steady state current of the heater recorded in a database; The method of claim 4 further comprising:

7. The method of claim 2 , wherein the wall property is one of a temperature property of the at least one exterior wall surface and a heat flux property of the at least one exterior wall surface.

8. acquiring a steady-state temperature of the at least one exterior wall surface in response to the chemical process operating at the steady-state; determining a temperature characteristic of the at least one exterior wall surface based on a difference between the steady-state temperature and a previous steady-state temperature of the at least one exterior wall surface recorded in a database; The method of claim 7 further comprising:

9. The method of claim 8 , wherein the steady-state temperature of the at least one exterior wall surface is obtained from a temperature sensor.

10. acquiring a steady-state heat flux of the at least one exterior wall surface in response to the chemical process operating at the steady-state; determining a heat flux characteristic of the at least one exterior wall surface based on a difference between the steady-state heat flux and a previous steady-state heat flux of the at least one exterior wall surface recorded in a database; The method of claim 7 further comprising:

11. The method of claim 9 , wherein the steady-state heat flux of the at least one exterior wall surface is obtained from a heat flux sensor.

12. The method of claim 1 , further comprising selectively taking corrective action based on the amount of polymer buildup.

13. 13. The method of claim 12, wherein the corrective action comprises generating a notification based on the amount of polymer buildup, adjusting one or more parameters of the chemical process, or a combination thereof.

14. The method of claim 1 , wherein the chemical process is a semiconductor process.

15. The method of claim 1 , wherein the chemical processing chamber is a semiconductor processing chamber.

16. 1. A system for monitoring polymer deposition in a chemical treatment chamber, comprising: a heater configured to generate thermal energy during a chemical process; a chemical processing chamber including a wafer and one or more exterior wall surfaces; a control system including a chemical process controller, a thermal controller, or a combination thereof; the control system determining whether the chemical process is operating at a steady state based on steady-state data of the chemical processing chamber based on the wafer temperature, a chemical process recipe, or a combination thereof; determining a response characteristic in response to the chemical process operating at a steady state and the heater generating the thermal energy, the response characteristic comprising an operating characteristic associated with the heater, a wall characteristic associated with the one or more exterior wall surfaces, or a combination thereof; correlating the response characteristic to an amount of polymer deposition in the chemical treatment chamber based on a response characteristic-polymer deposition correlation model and an emissivity range of the polymer deposition; selectively performing corrective action based on the amount of polymer buildup; A system that performs the following.

17. The system of claim 16 , wherein the operating characteristic is an electrical characteristic of the heater.

18. 20. The system of claim 17, wherein the electrical characteristic is a change in voltage of the heater when the chemical process is operating at the steady state, a change in current of the heater when the chemical process is operating at the steady state, or a combination thereof.

19. the control system obtaining a steady-state voltage of the heater in response to the chemical process operating at the steady-state; determining the electrical characteristic of the heater based on a difference between the steady-state voltage and a previous steady-state voltage of the heater recorded in a database; 20. The system of claim 18, configured to:

20. the control system obtaining a steady state current of the heater in response to the chemical process operating at the steady state; determining a current change for the heater based on a difference between the steady state current and a previous steady state current for the heater recorded in a database; 20. The system of claim 18, configured to:

21. The system of claim 16 , wherein the wall property is one of a temperature property of the at least one exterior wall surface and a heat flux property of the at least one exterior wall surface.

22. the control system obtaining a steady-state temperature of the at least one exterior wall surface in response to the chemical process operating at the steady-state; determining a temperature characteristic of the at least one exterior wall surface based on a difference between the steady-state temperature and a previous steady-state temperature of the at least one exterior wall surface recorded in a database; 22. The system of claim 21 configured to:

23. 23. The system of claim 22, wherein the steady-state temperature of the at least one exterior wall surface is obtained from a temperature sensor disposed on the wall.

24. the control system obtaining a steady-state heat flux of the at least one exterior wall surface in response to the chemical process operating at the steady-state; determining the heat flux characteristic of the at least one exterior wall surface based on a difference between the steady-state heat flux and a previous steady-state heat flux of the at least one exterior wall surface recorded in a database; 22. The system of claim 21 configured to:

25. 25. The system of claim 24, wherein the steady-state heat flux of the at least one exterior wall surface is obtained from a heat flux sensor disposed on the wall.

26. 17. The system of claim 16, wherein the corrective action comprises generating a notification based on the amount of polymer buildup, adjusting one or more parameters of the chemical process, or a combination thereof.

27. The system of claim 16 , wherein the chemical process is a semiconductor process.

28. 17. The system of claim 16, wherein the chemical treatment chamber is a semiconductor processing chamber.

29. 1. A method for monitoring polymer deposition in a chemical processing chamber including a wafer and one or more exterior wall surfaces, comprising: generating thermal energy during a chemical process by a heater; determining, by a control system, whether the chemical process is operating at a steady state based on steady-state data of the chemical processing chamber based on the wafer temperature, a chemical process recipe, or a combination thereof; determining, by the control system, a response characteristic in response to the heater generating the thermal energy when the chemical process is operating at a steady state, the response characteristic including an operating characteristic associated with the heater, a wall characteristic associated with the one or more exterior wall surfaces, or a combination thereof; correlating the response characteristic to an amount of polymer deposition in the chemical treatment chamber based on a response characteristic-polymer deposition correlation model and an emissivity range for the polymer deposition; selectively implementing corrective action by the control system based on the amount of polymer buildup; A method comprising:

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