TWI891211B - Systems and methods for determining polymer build-up within a chemical processing chamber - Google Patents

Abstract

A method for monitoring polymer build-up within a chemical processing chamber and in response to generating thermal energy during a chemical process includes determining a response characteristic in response to generating the thermal energy, where the response characteristic includes an operational characteristic associated with the heater, a wall characteristic associated with at least one external wall surface of the chemical processing chamber, or a combination thereof. The method includes correlating the response characteristic to an amount of polymer build-up within the chemical processing chamber based on a response characteristic-polymer build-up correlation model and an emissivity range of the polymer build-up.

Description

System and method for determining polymer accumulation in a chemical processing chamber Invention Field

The present disclosure relates to systems and methods for determining polymer buildup within a chemical processing chamber, such as a semiconductor processing chamber.

Invention Background

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

In various chemical processing environments, operators monitor various components to identify and diagnose potential problems and anomalies associated with them. For example, during semiconductor processing (e.g., a dry etch process), an operator may monitor the semiconductor processing chamber to detect polymer buildup on, for example, an interior wall surface, a liner, a showerhead, a heater surface, and other components.

As a more specific example, during a dry etching process, one or more precursor gases are employed to generate an etchant. As the dry etching process is repeated, a polymer (e.g., a fluorocarbon polymer) formed from the gas combination may be deposited and gradually thickened on, for example, the inner walls and/or lining of a semiconductor processing chamber. Furthermore, when the polymer thickness exceeds a threshold, the polymer deposit may erode and accumulate on the wafer or other components of the semiconductor processing chamber, thereby inhibiting wafer yield, causing wafer defects due to arcing, and/or causing undesirable parametric changes in the etching process to adapt to the polymer deposits.

Therefore, an operator may employ various polymer buildup monitoring procedures to detect polymer buildup and/or implement one or more corrective actions to address the buildup. For example, an operator may control the semiconductor processing environment to supply a purge/oxidizing gas to the semiconductor processing chamber, initiate a wet cleaning process according to a preventative maintenance plan, and/or employ a cleaning cycle after each wafer (or a predetermined number of wafers) is processed. However, these corrective procedures inhibit the efficiency of the semiconductor processing system because these corrective actions may require an operator to open the semiconductor processing chamber, clean the semiconductor processing chamber, and then close the semiconductor processing chamber upon completion of the cleaning cycle. Once the semiconductor processing chamber is exposed to the atmosphere, a pumping operation is performed to return the semiconductor processing chamber to a base vacuum level. This pumping operation can be resource- and time-intensive, thereby inhibiting chamber throughput. Specifically, these corrective actions do not incorporate in-situ detection and mitigation procedures to detect polymer buildup and/or implement appropriate corrective actions.

These and other problems of detecting polymer buildup and implementing corrective actions are addressed by this disclosure.

Summary of the Invention

This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.

The present disclosure provides a method for monitoring polymer accumulation in a chemical processing chamber in response to heat generated during a chemical process. The method includes determining a response characteristic in response to the heat generated, wherein the response characteristic includes an operating characteristic associated with a heater, a wall characteristic associated with at least one exterior wall surface of the chemical processing chamber, or a combination thereof. The method includes correlating the response characteristic with an amount of polymer accumulation in the chemical processing chamber based on a response characteristic-polymer accumulation correlation model and an emissivity range of the polymer accumulation.

The next paragraph includes variations of the method of the previous paragraph, and the variations may be implemented individually or in any combination while remaining within the scope of the present disclosure.

In one form, the method includes obtaining stability data, wherein the stability data is based on a temperature of a wafer in a chemical processing chamber, a chemical processing strategy, or a combination thereof; determining whether the chemical process is operating in a stable state based on the stability data; and determining a response characteristic in response to determining that the chemical process is operating in the stable state; the operating characteristic is an electrical characteristic of a heater; the electrical characteristic is a change in voltage of the heater when the chemical process is operating in the stable state, a change in current of the heater when the chemical process is operating in the stable state, or a combination thereof. The method comprises obtaining a steady-state voltage of the heater in response to the chemical process operating in the steady state; and 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 stored in a database; the method comprises obtaining a steady-state current of the heater in response to the chemical process operating in the steady state; and determining a change in the current of the heater based on a difference between the steady-state current and a previous steady-state current of the heater stored in a database; wherein the wall characteristic is a temperature of at least one outer wall surface The method comprises obtaining a steady-state temperature of the at least one outer wall surface in response to the chemical process operating in the steady state; and determining the temperature characteristic of the at least one outer wall surface based on a difference between the steady-state temperature and a previous steady-state temperature of the at least one outer wall surface stored in a database; the steady-state temperature of the at least one outer wall surface is obtained by a temperature sensor; the method comprises obtaining a steady-state heat flux of the at least one outer wall surface in response to the chemical process operating in the steady state; and The heat flux characteristic of the at least one outer wall surface is determined based on a difference between the steady-state heat flux and a previous steady-state heat flux of the at least one outer wall surface stored in a database; the steady-state heat flux of the at least one outer wall surface is obtained by a heat flux sensor; the method includes selectively performing a corrective action based on the amount of polymer accumulation; the corrective action includes generating a notification, adjusting one or more parameters of the chemical process, or a combination thereof based on the amount of polymer accumulation; the chemical process is a semiconductor process; and the chemical processing chamber is a semiconductor processing chamber.

The present disclosure also provides a system for monitoring polymer accumulation within a chemical processing chamber. The system includes a heater configured to generate heat during a chemical process; a chemical processing chamber comprising a wafer and at least one outer wall surface; and a control system comprising a chemical process controller, a thermal controller, or a combination thereof. The control system is configured to determine whether the chemical process is operating in a steady state based on stability data of the chemical processing chamber, wherein the stability data is based on a temperature of the wafer, a chemical process strategy, or a combination thereof; and to determine a response characteristic in response to the heat generated by the heater when the chemical process is operating in a steady state, wherein the response characteristic includes an operating characteristic associated with the heater, a wall characteristic associated with the at least one outer wall surface, or a combination thereof. The control system is configured to correlate the response characteristic to an amount of polymer accumulation in the chemical processing chamber based on a response characteristic-polymer accumulation correlation model and an emissivity range of the polymer accumulation; and selectively perform a corrective action based on the amount of polymer accumulation.

The next paragraph includes variations of the system in the previous paragraph, and the variations may be implemented individually or in any combination.

In one form, the operating characteristic is an electrical characteristic of the heater; the electrical characteristic is a voltage change of the heater when the chemical process operates in a steady state, a current change of the heater when the chemical process operates in 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 in the steady state; and the heater is determined to be in a steady-state state based on a difference between the steady-state voltage and a previous steady-state voltage of the heater stored in a database. The control system is configured to obtain a steady-state current of the heater in response to the chemical process operating in the steady state; and determine the current change of the heater based on a difference between the steady-state current and a previous steady-state current of the heater stored in a database; the wall characteristic is one of a temperature characteristic of at least one outer wall surface and a heat flux characteristic of at least one outer wall surface; the control system is configured to obtain a steady-state current of the heater in response to the chemical process operating in the steady state The control system is configured to obtain a steady-state temperature of the at least one outer wall surface; and determine the temperature characteristic of the at least one outer wall surface based on a difference between the steady-state temperature and a previous steady-state temperature of the at least one outer wall surface stored in a database; the steady-state temperature of the at least one outer wall surface is obtained by a temperature sensor disposed on the wall; the control system is configured to obtain a steady-state heat flux of the at least one outer wall surface in response to the chemical process operating in the steady state; and determine the temperature characteristic of the at least one outer wall surface based on the steady-state heat flux. The heat flux characteristic of the at least one outer wall surface is determined based on a difference between a measured amount of polymer accumulation and a previous steady-state heat flux of the at least one outer wall surface stored in a database; the steady-state heat flux of the at least one outer wall surface is obtained by a heat flux sensor disposed on the wall; the corrective action includes generating a notification based on the amount of polymer accumulation, adjusting one or more parameters of the chemical process, or a combination thereof; the chemical process is a semiconductor process; and the chemical process chamber is a semiconductor process chamber.

The present disclosure provides a method for monitoring polymer accumulation in a chemical processing chamber comprising a wafer and at least one outer wall surface. The method includes generating heat energy with a heater during a chemical process; determining, by a control system, whether the chemical process is operating in a steady state based on stability data of the chemical process chamber, wherein the stability data is based on a temperature of the wafer, a chemical process strategy, or a combination thereof; and determining, by the control system, a response characteristic in response to the heat energy generated by the heater when the chemical process is operating in a steady state, wherein the response characteristic includes an operation characteristic associated with the heater, a wall characteristic associated with the at least one outer wall surface, or a combination thereof. The method includes correlating, by the control system, the response characteristic to an amount of polymer accumulation in the chemical processing chamber based on a response characteristic-polymer accumulation correlation model and an emissivity range of the polymer accumulation; and selectively performing, by the control system, a corrective action based on the amount of the polymer accumulation.

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 this disclosure.

5: Chemical treatment environment

5-1: Semiconductor Processing Environment, Semiconductor Processing System

10: Chemical processing chamber

10-1: Semiconductor Processing Chamber, Processing Chamber

20: Gas delivery system

22: Gas Source

24: Gas supply line

26: Gas reduction system

28: Exhaust line

30: Fluid Line Heating System

32: Fluid Line Heater

34: Fluid Line Heater Sensor

36: Fluid Line Flow Sensor

42: Chamber wall

42A: Outer wall surface

42B: Inner wall surface

44: Lining

46: Chamber

48: Wafer

50: External wall surface sensor

60: Wafer support pedestal

62:pedestal heater

64: Pedestal sensor

70: Polymer accumulation

100:Chemical Process Control System

100-1: Semiconductor Processing System Control System (SPSCS)

105: Countermeasures Module

110: Thermal Controller

112: Power

114: Power Converter System

116: Heater control module

120: Response Characteristics Database

125: Chemical Process Controller

130: Status Module

140: Response characteristic module

150: Related modules

160: Response Characteristic-Polymer Packing Correlation (RCPBC) Database

170,170-1: Correction Action Module

171: State Vector Module

172: State Correction Action Module

173: Rewards Module

174: Project generation module

175: Status Correction Action Database

176: Target Correction Action Module, Target Action Module

180: Human-Machine Interface (HMI)

500,550,600,650:Program

504,508,512,554,558,562,604,608,612,616,620,654,658,662,666,670: Block

To facilitate a better understanding of the present disclosure, various aspects thereof will now be described by way of example with reference to the accompanying drawings, wherein: FIG. 1 is an exemplary chemical processing environment according to the teachings of the present disclosure; FIG. 2 is an exemplary semiconductor processing environment according to the teachings of the present disclosure; FIG. 3 is a functional block diagram of an exemplary semiconductor processing environment according to the teachings of the present disclosure; FIG. 4A is a functional block diagram of an exemplary control system according to the teachings of the present disclosure; and FIG. 4B is a functional block diagram of an exemplary correction action module according to the teachings of the present disclosure. Block diagram; FIG. 5A is a flow chart of an example process for monitoring polymer buildup in a chemical processing environment according to the teachings of the present disclosure; FIG. 5B is a flow chart of an example process for monitoring polymer buildup in a semiconductor processing environment according to the teachings of the present disclosure; FIG. 6A is a flow chart of another example process for monitoring polymer buildup in a chemical processing environment according to the teachings of the present disclosure; and FIG. 6B is a flow chart of another example process for monitoring polymer buildup in a semiconductor processing environment according to the teachings of the present disclosure.

The drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way.

Detailed description of the preferred embodiment

The following description is merely exemplary in nature and is not intended to limit the content, application, or uses of the present disclosure. It should be understood that throughout the drawings, corresponding reference numerals indicate similar or corresponding parts and features.

Referring to FIG. 1 , an example chemical processing environment 5 is shown and generally includes a chemical processing chamber 10 and a chemical processing control system 100. The chemical processing environment 5 is generally any type of environment in which one or more chemical processes are performed, such as a semiconductor processing environment, a combustion exhaust environment, a reaction vessel, a heat exchanger, an industrial dryer and separator for water treatment equipment, a fluid flow environment, and other types of chemical processing environments. As used herein, "fluid" refers to a gas, liquid, and/or plasma.

As an example and referring to FIG. 2 , a semiconductor processing environment 5-1 (referred to as the chemical processing environment 5) for performing one or more semiconductor processes (referred to as the chemical processing) is shown and includes a semiconductor processing chamber 10-1 (referred to as the chemical processing chamber 10), a gas delivery system 20, a fluid line heating system 30, and a semiconductor processing system control system (SPSCS) 100-1 (referred to as the chemical processing control system 100). In one form, the gas delivery system 20 includes a gas source 22, a gas supply line 24 for delivering process gas from the gas source 22 to the processing chamber 10-1, a gas abatement system 26, and an exhaust line 28 for delivering waste gas, such as post-processing gas, gas/plasma byproducts, and/or wafer-related waste, from the processing chamber 10-1 to the gas abatement system 26. In one form, the process gas used in semiconductor wafer processing can be pyrophoric or corrosive (e.g., fluoride, ammonia, silane, argon, arsine, and/or phosphine, among others). In some embodiments, unused process gas (e.g., argon or nitrogen) and undesirable byproducts are conveyed to the gas abatement system 26, where the unused process gas and byproducts are cleaned and neutralized before being released to the environment or sent to another downstream treatment. Hereinafter, process gas and waste gas may be collectively referred to as "gas."

In one form, the fluid line heating system 30 includes a plurality of fluid line heaters 32 positioned at various locations along the gas supply line 24 and the exhaust line 28 to heat the gas flowing therein. In one form, the fluid line heaters 32 are flexible heaters wrapped around the gas supply line 24 and the exhaust line 28 to heat the gas therein. Heating the gas as it is delivered from the processing chamber 10-1 to the gas abatement system 26 facilitates semiconductor processing performed in the processing chamber 10-1 and exhaust gas treatment in the gas abatement system 26. In addition, heating the gas inhibits the deposition of contaminants along the walls of the gas supply line 24 and the exhaust line 28, and thus inhibits blockages in the gas supply line 24 and the exhaust line 28.

In one embodiment, the fluid line heating system 30 includes a plurality of fluid line heater sensors 34 for generating fluid line heating system data, such as a temperature of the fluid line heater 32, a heat flux of the fluid line heater 32, and an electrical characteristic of the fluid line heater 32 (e.g., a voltage, a current, an electrical power, a resistance, a voltage change, a current change, an electrical power change, and/or a resistance change of the fluid line heater 32). The plurality of fluid line heater sensors 34 may include a thermocouple, a resistance temperature detector, an infrared camera, an inductive flow sensor, and/or a voltage sensor, among others.

In one form, the fluid line heaters 32 may generate electrical characteristics of the fluid line heater 32 in place of or in addition to one or more fluid line heater sensors 34. For example, the fluid line heater 32 is provided as a "two-wire" heater, which includes one or more resistive heating elements that function as a sensor and a heating element, the sensor being used to measure an average temperature of the resistive heating element based on its resistance. Thus, only two wires are used instead of four wires with a separate sensor. More specifically, such a two-wire bulk heater is disclosed in U.S. Patent No. 7,196,295, entitled "Two-wire bulk layer heater system," which is commonly owned by the present application and is incorporated herein by reference in its entirety. In a two-wire bulk heating system, the fluid line heating system 30 is an adaptive heating system that incorporates a heater design and has control means to incorporate power, resistance, voltage, and current into a customizable feedback control system to limit one or more of these parameters (i.e., power, resistance, voltage, and current) while controlling another. In one form, the controller is configured to monitor at least one of current, voltage, and power delivered to the resistive heating element to determine the resistance and temperature of the resistive heating element. More specifically, such an adaptive heating system and controller are disclosed in U.S. Patent No. 10,690,705, entitled "Power Converter for a Thermal System," and U.S. Patent No. 10,908,195, entitled "System and Method for Controlling Power Sent to a Heater," which are commonly owned by the present application and are incorporated herein by reference in their entirety.

In one embodiment, the gas delivery system 20 includes a plurality of fluid line flow sensors 36 positioned adjacent to (i.e., adjacent to and/or proximate to) the gas supply line 24 and the exhaust line 28 to measure fluid line data. For example, the fluid line flow sensors 36 are mounted on the exterior and/or interior surfaces of the gas supply line 24 and the exhaust line 28 to monitor temperatures that could cause blockages, heat sinks, and hot spots, leading to system degradation and downtime. In one embodiment, the fluid line data may include, but is not limited to, the temperature of the gas supply line 24/exhaust line 28, the flow rate and pressure of the gas, and the type of process gas. Therefore, the fluid line flow sensor 36 may include but is not limited to a temperature sensor, a pressure sensor, an anemometer, a pressure sensor, a flow rate sensor, a gas sensor, etc.

In one form, the SPSCS 100-1 is configured to control the operation of the fluid line heating system 30 and/or the gas delivery system 20 based on fluid line heating system data generated by the fluid line heater sensor 34 and/or fluid line data generated by the fluid line flow sensor 36, as well as other processed data. An example control program for controlling the operation of the fluid line heating system 30 and/or the gas delivery system 20 is disclosed in U.S. Patent Application No. 17/306,200, entitled "Method for Monitoring Surface Condition of a Component," which is commonly owned by the present application and is incorporated herein by reference in its entirety.

In one form, a 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. It should be understood that the semiconductor processing chamber 10-1 may include other components (e.g., a lid, a showerhead, and other components) and is not limited to the components illustrated and/or described herein. In one form, 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 together define the chamber 46. Typically, the wafer 48 is disposed on an upper surface of the wafer support pedestal 60 (e.g., an electrostatic chuck), as shown during semiconductor processing.

In one embodiment, one or more outer wall surface sensors 50 are disposed on the outer wall surface 42A (e.g., secured, attached, and/or fixed to the outer wall surface 42A) and configured to generate sensor data corresponding to a wall property of the outer wall surface 42A. For example, the outer wall surface sensor 50 may be provided by a temperature sensor configured to generate temperature data associated with the outer wall surface 42A and/or a heat flux sensor configured to generate heat flux data associated with the outer wall surface 42A. As described in further detail below, the SPSCS 100-1 is configured to determine the wall property (e.g., a temperature property and/or a heat flux property) of the outer wall surface 42A based on the sensor data generated by the one or more outer wall surface sensors 50. It should be understood that any configuration and/or number of the outer wall surface sensors 50 may be provided, such that various mathematical representations of the sensor data (e.g., a trend, average, median, maximum, minimum, etc.) may be provided to the SPSCS 100-1. Furthermore, while the one or more outer wall surface sensors 50 are shown as being disposed on the outer wall surface 42A, it should be understood that in some variations, the one or more outer wall surface sensors 50 may be disposed on the inner wall surface 42B.

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 may each include one or more resistive heating elements that provide (e.g., increase or decrease) thermal energy to the wafer 48 and together define one or more heating zones. The SPSCS 100-1 may independently and selectively control the thermal energy provided to the wafer 48 based on pedestal sensor data generated by the pedestal sensor 64, which may be indicative of a temperature of the one or more pedestal heaters 62 and/or the wafer 48, a heat flux of the one or more pedestal heaters 62 and/or the wafer 48, an electrical characteristic of the one or more pedestal heaters 62 (e.g., a voltage, a current, an electrical power, a resistance, a voltage change, a current change, an electrical power change, and/or a resistance change of the one or more pedestal heaters 62), and the like. By way of example, the pedestal sensor 64 may include, but is not limited to, a temperature sensor, thermocouple, RTD, infrared sensor, fiber optic sensor, clamped electrode, radio frequency (RF) antenna, and/or other commonly used temperature sensing devices. Example pedestal heaters and sensors are disclosed in U.S. Patent No. 11,382,180, entitled "Multi-Zone Pedestal Heater with Routing Layer," and U.S. Patent No. 11,343,879, entitled "Multi-Zone Pedestal Heater without Through-Via," which are commonly owned by the present application and are incorporated herein by reference in their entirety.

While 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 external to the wafer support pedestal 60. In one variation, when heat is externally supplied to the fluid (e.g., gas) via the gas supply line 24 to provide plasma to the chamber 46, the pedestal does not include the pedestal heater 62. Furthermore, it should be understood that when the pedestal heater 62 is a "two-wire" heater built into the wafer support pedestal 60, the pedestal sensor 64 may be removed.

2-3 , the SPSCS 100-1 is configured to monitor polymer accumulation 70 within the chamber 46, such as along the inner wall surface 42B and/or the lining 44. In one embodiment, the SPSCS 100-1 includes a countermeasure module 105, a thermal controller 110, a response characteristic database 120, and a chemical process controller 125. The chemical process controller 125 may include a state module 130, a response characteristic module 140, a correlation module 150, a response characteristic-polymer accumulation correlation (RCPBC) database 160, a corrective action module 170, and a human-machine interface (HMI) 180. In one form, the components of SPSCS 100-1 are communicatively coupled using a wired communication protocol and/or a wireless communication protocol (e.g., a Bluetooth®-type protocol, a cellular protocol, a Wireless Fidelity (Wi-Fi)-type protocol, a Near Field Communication (NFC) protocol, an Ultra Wideband (UWB) protocol, etc.).

In one form, the strategy module 105 is configured to define a chemical process strategy to be implemented by the SPSCS 100-1 based on a user input received by the HMI 180. As used herein, a "chemical process strategy" refers to one or more predefined parameters of a chemical process. Example predefined parameters of the chemical process include, but are not limited to, a process type (e.g., a dry etch process, a vapor deposition process, and other processes), gas temperature, a composition of the process gas/plasma to be supplied to the semiconductor processing chamber 10-1, and/or one or more set-point operating characteristics (e.g., set-point electrical characteristics and/or temperature characteristics) of the fluid line heater 32 and/or the pedestal heater 62.

In one embodiment, referring to Figures 3 and 4A , the thermal controller 110 is configured to control the operation of the one or more pedestal heaters 62 to generate heat during semiconductor processing (e.g., the chemical processing). In one embodiment, the thermal controller 110 includes a power supply 112, a power converter 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 converter system 114 via, for example, an interlock (not shown). The interlock can be operated by the heater control module 116 as a safety mechanism to cut off power from the power supply 112.

The power converter system 114 is configured to regulate the input voltage based on a control signal received from the heater control module 116 and apply an output voltage (V _OUT ) to the one or more pedestal heaters 62. In one form, the power converter system 114 includes a plurality of power converters configured to apply an adjustable power to the resistive heating elements of the one or more pedestal heaters 62 based on the control signal. An example power converter system is described in co-pending U.S. application Ser. No. 15/624,060, filed Jun. 15, 2017, and entitled “POWER CONVERTER FOR A THERMAL SYSTEM,” which is commonly owned by the present application and is incorporated herein by reference in its entirety. In this example, each power converter comprises a step-down converter operable by its heater controller to generate a desired output voltage for one or more heating elements in a given zone. Thus, the power converter system is operable to provide a customizable amount of power (i.e., a desired power) to each of the one or more pedestal heaters 62. It should be readily understood that other power converter systems may be employed to provide the desired power and that the present disclosure is not limited to the examples provided herein.

In one form, the heater control module 116 is configured to generate and provide a control signal to the power converter system 114 based on pedestal sensor data generated by the pedestal sensor 64. For example, and in response to receiving a chemical process strategy from the strategy module 105, the heater control module 116 is configured to generate and provide a control signal for adjusting the duty cycle of the power converter system 114, thereby increasing or decreasing an output voltage applied to the pedestal heater 62 based on the strategy. In response to receiving the output voltage, the one or more pedestal heaters 62 are configured to generate thermal energy to control, for example, the temperature of the wafer 48 during semiconductor processing. In one form, the heater control module 116 is configured to determine an electrical characteristic of the pedestal heater 62 based on the pedestal sensor data generated by the pedestal sensor 64. Furthermore, the heater control module 116 is configured to store the determined electrical characteristic of the pedestal heater 62 along with a corresponding timestamp in the response characteristic database 120. As described in further detail below, the chemical process controller 125 can determine whether the semiconductor process is operating in a stable state based on the data stored in the response characteristic database 120.

In one embodiment, referring to FIG. 3 , the state module 130 obtains stability data and determines whether the semiconductor process is operating in a stable state based on the stability data. The stability data is based on a temperature of the wafer 48 as indicated by the pedestal sensor data and/or a chemical process defined by the countermeasure module 105 . In one embodiment, the state module 130 determines whether the semiconductor process is operating in a stable state in response to heat generated by the pedestal heater 62 . When the inner wall surface 42B of the chamber 46 is clean (e.g., substantially free of contaminants, such as after a wet cleaning process on the inner wall surface 42B or when the chamber 46 is new) and therefore does not have an appreciable amount of polymer accumulation 70, the state module 130 can obtain baseline stability data. As described in further detail below, the response characteristic module 140 can determine a response characteristic based on a comparison between the baseline stability data and stability data obtained after one or more semiconductor processing cycles are completed.

For example, the status module 130 obtains the type of chemical process strategy (e.g., a dry etch process) from the strategy module 105 and determines that the semiconductor process is operating in a stable state after a predetermined period of time has elapsed and the pedestal heater 62 has begun producing the thermal energy defined by the chemical process strategy (e.g., increasing the temperature of the wafer 48). As another example, the status module 130 determines that the semiconductor process is operating in a stable state when the temperature of the wafer 48 (as indicated by the pedestal sensor data) has stabilized or settled near a setpoint temperature defined by the chemical process strategy.

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 heat and/or the status module 130 determining that the semiconductor process is operating in a stable 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 outer 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 of the pedestal heater 62 (e.g., a voltage and/or current change), a temperature characteristic of the pedestal heater 62 (e.g., a temperature change), a performance characteristic of the pedestal heater 62, or a combination thereof. Furthermore, the wall property of the at least one outer wall surface 42A may be a temperature property (e.g., a temperature change) and/or a heat flux property (e.g., a heat flux change) of the at least one outer wall surface 42A. Additional details regarding the electrical property, the temperature property, the wall property, and the heat flux property are provided below.

For example, when the semiconductor process is operating in a steady state, the response characteristic module 140 determines a voltage change of the pedestal heater 62 (as the electrical characteristic of the pedestal heater 62). To determine the voltage change of the pedestal heater 62, the response characteristic module 140 obtains a steady-state voltage of the pedestal heater 62 from the heater control module 116 and a previous steady-state voltage of the pedestal heater 62 determined by the heater control module 116 and stored in the response characteristic database 120 (i.e., a steady-state voltage with a previous timestamp). For example, the response characteristic module 140 determines a voltage change in the pedestal heater 62 based on a difference/trend between the acquired or measured steady-state voltage and a baseline steady-state voltage stored in the response characteristic database 120 (i.e., the steady-state voltage when the semiconductor processing chamber 10-1 is clean and does not have appreciable polymer buildup 70). The response characteristic module 140 then determines a voltage change based on the difference/trend between the steady-state voltage and the previous steady-state voltage.

As another example, when the semiconductor process is operating in a steady state, the response characteristic module 140 determines a current change of the pedestal heater 62 (as the electrical characteristic of the pedestal heater 62). To determine the current change of the pedestal heater 62, the response characteristic module 140 obtains a steady-state current of the pedestal heater 62 from the heater control module 116 and a previous steady-state current of the pedestal heater 62 determined by the heater control module 116 and stored in the response characteristic database 120 (i.e., a steady-state current with a previous timestamp). For example, the response characteristic module 140 determines a current change in the pedestal heater 62 based on a difference/trend between the acquired or measured steady-state current and a baseline steady-state current stored in the response characteristic database 120 (i.e., the steady-state current when the semiconductor processing chamber 10-1 is clean and does not have appreciable polymer buildup 70). The response characteristic module 140 then determines a current change based on the difference/trend between the steady-state current and the previous steady-state current.

As yet another example, when the one or more outer wall surface sensors 50 include a temperature sensor, the response characteristic module 140 determines a temperature characteristic of at least one outer wall surface 42A (serving as the wall characteristic). To determine the temperature characteristic of the at least one outer wall surface 42A, the response characteristic module 140 determines a steady-state temperature of the outer wall surface 42A (i.e., the temperature of the outer wall surface 42A when the semiconductor process is in a steady state) based on the temperature data generated by the temperature sensor (serving as the one or more outer wall surface sensors 50). In addition, the response characteristic module 140 obtains a previous steady-state temperature determined by the response characteristic module 140 and stored in the response characteristic database 120 (i.e., a steady-state temperature with a previous timestamp, such as a baseline steady-state temperature when the semiconductor processing chamber 10-1 is clean and does not have appreciable polymer accumulation 70) and determines the temperature characteristic based on the difference/trend between the steady-state temperature and the previous steady-state temperature.

As another example, when the one or more outer wall surface sensors 50 include a heat flux sensor, the response characteristic module 140 determines a heat flux characteristic of at least one outer wall surface 42A (as the wall characteristic). To determine the heat flux characteristic of the at least one outer wall surface 42A, the response characteristic module 140 determines a steady-state heat flux of the outer wall surface 42A (i.e., the heat flux of the outer wall surface 42A when the semiconductor process is in a steady state) based on the heat flux data generated by the heat flux sensor (as the one or more outer wall surface sensors 50). In addition, the response characteristic module 140 obtains a previous steady-state heat flux determined by the response characteristic module 140 and stored in the response characteristic database 120 (i.e., a steady-state heat flux with a previous timestamp, such as a baseline steady-state heat flux when the semiconductor processing chamber 10-1 is clean and does not have appreciable polymer accumulation 70) and determines the heat flux characteristic based on the difference/trend between the steady-state heat flux and the previous steady-state heat flux.

In one form, the correlation module 150 correlates the response characteristic with a quantity (e.g., a volume, thickness, and/or profile) of the polymer deposit 70 within the semiconductor processing chamber 10-1 based on a response characteristic-polymer deposit correlation (RCPBC) model stored in the RCPBC database 160 and an emissivity range of the polymer deposit 70. In one form, the RCPBC model is a table that maps the response characteristic (e.g., operating characteristics 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) and a known emissivity range (e.g., 0 to 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 a quantity of the polymer deposit 70. The known emissivity range of the polymer stack 70 can be defined based on, for example, the type of polymer stack 70. The RCPBC database 160 can store multiple RCPBC models for various emissivity ranges and wall property types.

As an example, the RCPBC model is an empirically defined and/or mathematically based model that maps steady-state voltage and/or current variations and a known range of emissivity of the polymer stack to the volume of the polymer stack 70. As another example, the RCPBC model is an empirically defined and/or mathematically based model that maps steady-state temperature and/or heat flux variations (as the wall properties) and a known range of emissivity of the polymer stack 70 to the volume of the polymer stack 70.

In one embodiment, 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. Therefore, the correlation module 150 can be configured to perform a machine learning process (such as a supervised learning process, an unsupervised learning process, a reinforcement learning process, a self-learning process, and/or a black-box modeling process) based on the RCPBC model to determine the amount of polymer accumulation 70.

As an example, the RCPBC model is a supervised learning model, such as a recurrent regression model or a multivariate regression model (e.g., 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, among others). That is, when the correlation module 150 performs a supervised learning process based on the RCPBC, the correlation module 150 can correlate a known emissivity range of the polymer stack 70 and at least one of the voltage change, current change, heat flux change, and temperature change with the amount of the polymer stack 70. Additionally, the correlation module 150 can repeatedly perform the supervised learning process for various amounts, emissivity ranges, and wall properties of the polymer deposit 70 to improve the accuracy of the RCPBC.

As another example, the RCPBC model is an unsupervised learning model, such as a cluster model. That is, when the correlation module 150 performs an unsupervised learning process based on the RCPBC, the correlation module 150 may generate a feature vector having any number of dimensions (e.g., an n-dimensional vector) based on a known emissivity range of the polymer stack 70 and at least one of the voltage change, current change, heat flux change, and temperature change. The association module 150 may then group the feature vectors into a plurality of clusters by performing a connectivity-based clustering procedure, a self-organizing map (SOM) clustering procedure, a centroid-based clustering procedure, a density-based clustering procedure, etc., or a distribution-based clustering procedure. The association module 150 may then classify the polymer accumulation 70 into one or more polymer accumulation ranges based on the clusters by, for example, performing a dimensionality reduction procedure (e.g., a principal component analysis (PCA) procedure) to reduce the dimensionality of the clusters to a predetermined dimensionality with maximum feature influence and classifying the clusters into one or more polymer accumulation ranges.

In one form, the corrective action module 170 is configured to selectively perform a corrective action based on the amount of polymer buildup 70. For example, the corrective action may include instructing the HMI 180 to generate a notification when the amount of polymer buildup 70 is greater than a threshold. The notification may include information indicating the amount of polymer buildup 70 and/or operator instructions for resolving the excessive polymer buildup 70 (e.g., operator instructions to provide a purge/oxidizing gas to the semiconductor processing chamber 10-1 or initiate a wet clean process). As another example, the corrective action may include instructing the countermeasure module 105 to adjust one or more parameters of the semiconductor process countermeasure, such as gas temperature and/or one or more set point operating characteristics of the fluid line heater 32 and/or the pedestal heater 62.

To implement the functionality described herein, HMI 180 may be provided by a computing device (e.g., a smartphone, a laptop, a desktop computing device, a programmable logic controller, a tablet computer, etc.), including various visual interfaces (e.g., a touch screen, a display screen, an augmented reality device, and/or a plurality of light-emitting diodes (LEDs)), an auditory interface (e.g., a communication circuit for audibly outputting a message corresponding to the notification), and/or a tactile interface (e.g., a vibration motor circuit for selectively vibrating).

In one embodiment, the corrective action module 170 is configured to perform corrective actions based on the amount of polymer accumulation 70 and based on a machine learning process, such as a supervised learning process, an unsupervised learning process, a reinforcement learning process, a self-learning process, and/or a black-box modeling process, to select appropriate corrective actions. For example, as shown in FIG. 4B , the corrective action module 170-1 (serving as the corrective action module 170) is configured to perform a reinforcement learning process to select an appropriate corrective action based on the amount of polymer accumulation 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 of which indicates the amount of polymer accumulation 70 at a given discrete time value.

In one form, the state corrective action module 172 defines multiple corrective actions associated with the state vector. The multiple corrective actions may include, but are not limited to, instructing the gas source 22 to provide a cleaning/oxidizing gas to the semiconductor processing chamber 10-1, instructing the gas source 22 to initiate a wet purge process, adjusting a gas temperature, adjusting one or more setpoint operating characteristics of the fluid line heater 32, adjusting one or more setpoint operating characteristics of the pedestal heater 62, interrupting power to the pedestal heater 62 via an interlock (not shown), and a state-maintaining action. As used herein, a "state-maintaining action" means not performing a corrective action. In one form, the state corrective action module 172 defines corrective actions for various amounts of polymer buildup 70 for each corrective action type.

In one form, the reward module 173 is configured to determine a reward for each corrective action using a known reinforcement learning procedure (e.g., a Q-learning procedure with a learning rate between 0 and 1). The reward value is indicative of a qualitative and/or quantitative metric associated with an expected resulting change in chamber throughput, an efficiency of the semiconductor processing system 5-1, or a combination thereof. For example, a larger reward value may correspond to an improved qualitative/quantitative metric associated with the resulting chamber throughput and/or the efficiency of the semiconductor processing system 5-1, while a smaller reward value may correspond to a deteriorated qualitative/quantitative metric associated with the resulting chamber throughput and/or the efficiency of the semiconductor processing system 5-1.

In one embodiment, the item generation module 174 associates each corrective action generated by the state corrective action module 172 with a corresponding reward value generated by the reward module 173. In another embodiment, the item generation module 174 generates an entry for each pair of state corrective action and reward value and stores the generated entry in the state corrective action database 175. In another embodiment, the target action module 176, once fully trained, autonomously selects the corrective action to be performed based on the entries in the state corrective action database 175 and the associated reward values.

Referring to FIG. 5A , a flow chart illustrating a process 500 for monitoring polymer buildup within a chemical processing chamber 10 is presented. At block 504 , the chemical process control system 100 generates heat during a chemical process. At block 508 , the chemical process control system 100 determines a response characteristic in response to the generation of the heat. At block 512 , the chemical process control system 100 correlates the response characteristic with an amount of polymer buildup within the chemical processing chamber 10 based on an RCPBC model and an emissivity range of the polymer buildup.

Referring to FIG. 5B , a flow chart illustrating a process 550 for monitoring polymer accumulation 70 within a semiconductor processing chamber 10 - 1 is presented. At block 554 , the SPSCS 100 - 1 generates thermal energy during semiconductor processing. At block 558 , the SPSCS 100 - 1 determines a response characteristic in response to the generation of the thermal energy. At block 562 , the SPSCS 100 - 1 correlates the response characteristic with an amount of polymer accumulation within the semiconductor processing chamber 10 - 1 based on an RCPBC model and an emissivity range of the polymer accumulation 70 .

6A , a flow chart illustrating a process 600 for monitoring polymer buildup within a chemical processing chamber 10 is presented. At block 604, the chemical process control system 100 generates heat during a chemical process. At block 608, the chemical process control system 100 determines whether the chemical process is operating in a steady state based on steady-state data from the chemical processing chamber 10. If the chemical process is not operating in a steady state, the process 600 proceeds to block 604. If the chemical process is operating in a steady state at block 608, the process 600 proceeds to block 612, where the chemical process control system 100 determines a response characteristic. At block 616, the chemical process control system 100 correlates the response characteristic to an amount of polymer buildup within the chemical process chamber based on the RCPBC model and an emissivity range of the polymer buildup. At block 620, the chemical process control system 100 selectively performs a corrective action based on the amount of polymer buildup.

Referring to FIG. 6B , a flow chart illustrating a process 650 for monitoring polymer buildup within a semiconductor processing chamber 10-1 is presented. At block 654 , the SPSCS 100-1 generates heat during a semiconductor process. At block 658 , the SPSCS 100-1 determines whether the semiconductor process is operating in a steady state based on steady-state data from the semiconductor processing chamber 10-1. If the semiconductor process is not operating in a steady state, the process 650 proceeds to block 654 . If the semiconductor process is operating in a steady state at block 658 , the process 650 proceeds to block 662 , where the SPSCS 100-1 determines a response characteristic. At block 666, the SPSCS 100-1 correlates the response characteristic to an amount of polymer accumulation 70 within the semiconductor processing chamber 10-1 based on the RCPBC model and an emissivity range of the polymer accumulation 70. At block 670, the SPSCS 100-1 selectively performs a corrective action based on the amount of polymer accumulation.

The present disclosure described herein provides systems and methods for monitoring polymer buildup within a chemical processing chamber. A control system generates thermal energy during a chemical process and determines a response characteristic in response to the generation of the thermal energy. The response characteristic includes an operating characteristic associated with a heater, a wall characteristic associated with at least one outer wall surface of the chemical processing chamber, or a combination thereof. The control system correlates the response characteristic to an amount of polymer buildup within the chemical processing chamber based on a response characteristic-polymer buildup correlation model and an emissivity range for the polymer buildup. Thus, the control system implements an in-situ based monitoring process to accurately monitor polymer thickness to improve wafer yield, suppress wafer defects, and suppress undesirable shifts in accommodating polymer deposits during a chemical process (e.g., semiconductor processing). Furthermore, the control system improves the efficiency of the chemical processing system with respect to, for example, cycle time and/or the number of wafers produced in a given period of time.

Unless otherwise expressly stated herein, all numerical values indicating mechanical/thermal properties, composition percentages, dimensions and/or tolerances or other characteristics should be understood as being modified by the word "about" or "approximately" when describing the scope of the present disclosure. Such modifications are desirable for various reasons, including industrial practice, material, manufacturing and assembly tolerances, and testing capabilities.

As used herein, the phrase at least one of A, B, and C should be interpreted to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C."

In this application, the terms "controller" and/or "module" may refer to any or all of the following: an application-specific integrated circuit (ASIC); a digital, analog, or hybrid analog/digital discrete circuit; a digital, analog, or hybrid analog/digital integrated circuit; a combination of logic circuits; a field-programmable gate array (FPGA); a processor circuit (shared, dedicated, or grouped) that executes code; a memory circuit (shared, dedicated, or grouped) that stores code executed by the processor circuit; other appropriate hardware components that provide the functionality described; or a combination of some or all of the above, such as in a system-on-a-chip.

The term memory is a subset of the term computer-readable medium. The term computer-readable medium, as used herein, does not encompass transient electrical or electromagnetic signals propagating through a medium (e.g., on a carrier wave); the term computer-readable medium is therefore considered tangible and non-transitory. Non-limiting examples of non-transitory, tangible computer-readable media are non-volatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a masked read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital tape or a hard drive), and optical storage media (such as a CD, a DVD, or a Blu-ray disc).

The apparatus and methods described in this application may be implemented partially or completely by a special-purpose computer generated by adapting a general-purpose computer architecture to perform one or more specific functions embodied in a computer program. The aforementioned function blocks, flow chart components, and other elements are software specifications that can be translated into a computer program through routine work by a person skilled in the art or programmer.

The descriptions in this disclosure are merely illustrative in nature, and variations that do not depart from the subject matter of this disclosure are intended to be within the scope of this disclosure. Such variations should not be regarded as departing from the spirit and scope of this disclosure.

500: Program

504,508,512: Block

Claims (29)

A method for monitoring polymer accumulation in a chemical processing chamber in response to heat generated during a chemical process comprises: Determining a response characteristic in response to the generation of heat, wherein the response characteristic comprises an operating characteristic associated with a heater, a wall characteristic associated with at least one exterior wall surface of the chemical processing chamber, or a combination thereof; and Correlating the response characteristic with an amount of polymer accumulation in the chemical processing chamber based on a response characteristic-polymer accumulation correlation model and an emissivity range of the polymer accumulation. The method of claim 1, further comprising: obtaining steady-state data, wherein the steady-state data is based on a temperature of a wafer in the chemical processing chamber, a chemical processing strategy, or a combination thereof; determining whether the chemical process is operating in a steady-state based on the steady-state data; and determining the response characteristic in response to determining that the chemical process is operating in the steady-state. The method of claim 2, wherein the operating characteristic is an electrical characteristic of the heater. The method of claim 3, wherein the electrical characteristic is a voltage change in the heater when the chemical process operates in the steady state, a current change in the heater when the chemical process operates in the steady state, or a combination thereof. The method of claim 4 further comprising: obtaining a steady-state voltage of the heater in response to the chemical process operating in the steady-state; and 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 stored in a database. The method of claim 4 further comprising: obtaining a steady-state current of the heater in response to the chemical process operating in the steady-state; and determining a change in the current of the heater based on a difference between the steady-state current and a previous steady-state current of the heater stored in a database. The method of claim 2, wherein the wall property is one of a temperature property of the at least one outer wall surface and a heat flux property of the at least one outer wall surface. The method of claim 7, further comprising: obtaining a steady-state temperature of the at least one outer wall surface in response to the chemical treatment being performed in the steady state; and determining the temperature characteristic of the at least one outer wall surface based on a difference between the steady-state temperature and a previous steady-state temperature of the at least one outer wall surface stored in a database. The method of claim 8, wherein the steady-state temperature of the at least one outer wall surface is obtained by a temperature sensor. The method of claim 7, further comprising: obtaining a steady-state heat flux of the at least one outer wall surface in response to the chemical treatment operating in the steady state; and determining the heat flux characteristic of the at least one outer wall surface based on a difference between the steady-state heat flux and a previous steady-state heat flux of the at least one outer wall surface stored in a database. The method of claim 9, wherein the steady-state heat flux of the at least one outer wall surface is obtained by a heat flux sensor. The method of claim 1, further comprising selectively performing a corrective action based on the amount of polymer buildup. 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. The method of claim 1, wherein the chemical treatment is a semiconductor treatment. The method of claim 1, wherein the chemical processing chamber is a semiconductor processing chamber. A system for monitoring polymer accumulation in a chemical processing chamber, the system comprising: a heater configured to generate heat during a chemical process; the chemical processing chamber comprising a wafer and at least one exterior wall surface; and a control system comprising a chemical process controller, a thermal controller, or a combination thereof, the control system configured to: determine whether the chemical process is operating in a stable state based on stability data of the chemical processing chamber, wherein the stability data is based on a temperature of the wafer, a chemical process strategy, or a combination thereof; Determining a response characteristic in response to the heat energy generated by the heater while the chemical process is operating in a steady state, wherein the response characteristic includes an operating characteristic associated with the heater, a wall characteristic associated with the at least one outer wall surface, or a combination thereof; correlating the response characteristic to an amount of polymer accumulation within the chemical processing chamber based on a response characteristic-polymer accumulation correlation model and an emissivity range of the polymer accumulation; and selectively performing a corrective action based on the amount of polymer accumulation. The system of claim 16, wherein the operating characteristic is an electrical characteristic of the heater. The system of claim 17, wherein the electrical characteristic is a change in voltage across the heater when the chemical process operates in the steady state, a change in current across the heater when the chemical process operates in the steady state, or a combination thereof. The system of claim 18, wherein the control system is configured to: obtain a steady-state voltage of the heater in response to the chemical process operating in the 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 stored in a database. The system of claim 18, wherein the control system is configured to: obtain a steady-state current of the heater in response to the chemical process operating in the steady-state; and determine a change in the current of the heater based on a difference between the steady-state current and a previous steady-state current of the heater stored in a database. The system of claim 16, wherein the wall property is one of a temperature property of the at least one outer wall surface and a heat flux property of the at least one outer wall surface. The system of claim 21, wherein the control system is configured to: obtain a steady-state temperature of the at least one outer wall surface in response to the chemical process operating in the steady state; and determine the temperature characteristic of the at least one outer wall surface based on a difference between the steady-state temperature and a previous steady-state temperature of the at least one outer wall surface stored in a database. A system as claimed in claim 22, wherein the steady-state temperature of the at least one outer wall surface is obtained by a temperature sensor disposed on the wall. The system of claim 21, wherein the control system is configured to: obtain a steady-state heat flux of the at least one outer wall surface in response to the chemical process operating in the steady state; and determine the heat flux characteristic of the at least one outer wall surface based on a difference between the steady-state heat flux and a previous steady-state heat flux of the at least one outer wall surface stored in a database. A system as claimed in claim 24, wherein the steady-state heat flux of the at least one outer wall surface is obtained by a heat flux sensor disposed on the wall. 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. The system of claim 16, wherein the chemical treatment is a semiconductor treatment. The system of claim 16, wherein the chemical processing chamber is a semiconductor processing chamber. A method for monitoring polymer accumulation in a chemical processing chamber comprising a wafer and at least one outer wall surface, the method comprising: generating heat energy by a heater during a chemical process; determining by a control system whether the chemical process is operating in a steady state based on steady state data of the chemical process chamber, wherein the steady state data is based on a temperature of the wafer, a chemical process strategy, or a combination thereof; determining by the control system a response characteristic in response to the heat energy generated by the heater when the chemical process is operating in the steady state, wherein the response characteristic includes an operating characteristic associated with the heater, a wall characteristic associated with the at least one outer wall surface, or a combination thereof; The control system relates the response characteristic to an amount of polymer accumulation in the chemical processing chamber based on a response characteristic-polymer accumulation correlation model and an emissivity range of the polymer accumulation; and the control system selectively performs a corrective action based on the amount of polymer accumulation.