Advanced control systems and methods for temperature control

Abstract

Methods and systems for controlling a heater, for example within a semiconductor etch operation, include generating first control signals to the heater based on setpoint temperature data; storing, in a data storage device, sample data associated with the first control signals generated over a time period; computing, by a processor, at least one signal adjustment value based on the sample data; applying, by the processor, the at least one signal adjustment value to subsequent control signals to provide adjusted control signals; and generating the adjusted control signals to the heater.

Description

ADVANCED CONTROL SYSTEMS AND METHODS FOR TEMPERATURECONTROLCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Patent Application No. 63 / 663,368, filed on June 24, 2024. The disclosure of the above application is incorporated herein by reference.FIELD

[0002] The present disclosure relates to control systems, and more particularly to temperature control systems for controlling temperature of a semiconductor during an in-chamber process.BACKGROUND

[0003] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0004] Etching is the process used to remove material from a surface of a substrate. Dry or semi-dry etching uses a gaseous mixture along with electrode control to remove the material. For example, a plasma created from oxygen, argon, CF4 or other appropriate gas can be used to dry etch a surface. Plasma etching can be used in the manufacture of semiconductors to produce patterns on silicon wafers for receiving microelectronic and dielectric devices.

[0005] The temperature of the silicon wafer affects the uniformity and other characteristics of the etching process. In some instances, the temperature of the wafer is controlled via a heater associated with the wafer. For example, the heater can be incorporated into a pedestal or chuck of the etching system that is configured to secure the wafer during the etching process.

[0006] Gas entry and other factors can cause temperature disturbances in the etching system. Such disturbances can affect the temperature of the wafer. These challenges associated with controlling temperature of the wafer during semiconductor processing are addressed by the present disclosure.SUMMARY

[0007] This section provides a general summary of the disclosure and isnot a comprehensive disclosure of its full scope or all of its features.

[0008] Methods, systems, and computer program products are provided for controlling a heater of an etching system. In various forms, the method includes: generating first control signals to the heater based on setpoint temperature data; storing, in a data storage device, sample data associated with the first control signals generated over a time period; computing, by a processor, at least one signal adjustment value based on the sample data; applying, by the processor, the at least one signal adjustment value to subsequent control signals to provide adjusted control signals; and generating the adjusted control signals to the heater. Additional features are provided in the following, which may be implemented individually or in any combination while remaining within the scope of the present disclosure.

[0009] In various forms, the at least one signal adjustment value includes an attenuation gain value.

[0010] In various forms, the computing the at least one signal adjustment value comprises computing the attenuation gain value based on a computed integral square deviation.

[0011] In various forms, the at least one signal adjustment value includes a lead time value.

[0012] In various forms, the computing the at least one signal adjustment value includes computing the lead time value based on a computed integral square deviation.

[0013] In various forms, the at least one signal adjustment value further includes an attenuation gain value.

[0014] In various forms, the method includes associating with the sample data batch type data and storing the associated data in the data storage device.

[0015] In various forms, the batch type data is based on one or more of a target object processed by the etching system, and an attribute of the etching system.

[0016] In various forms, the time period is predefined based on a total batch time.

[0017] In various forms, the time period is less than the total batch time.

[0018] In various forms, the generating the first control signals is further based on feedback temperature data.

[0019] In various forms, the generating the first control signals is furtherbased on at least one of a proportional term, an integral term, and a derivative term determined from the setpoint temperature data and the feedback temperature data.

[0020] In another form, a system includes: a data storage device that stores sample data associated with first control signals generated over a time period; a feedback module configured to, by a processor, generate control data based on a desired setpoint temperature; a feedforward module configured to, by a processor, compute at least one signal adjustment value based on the sample data; and a signal generator module configured to, by a processor, apply the at least one signal adjustment value to the control data to provide adjusted control signals, and generate the adjusted control signals to the heater.

[0021] In various forms, the at least one signal adjustment value includes an attenuation gain value.

[0022] In various forms, the feedforward module computes the at least one signal adjustment value as the attenuation gain value based on a computed integral square deviation.

[0023] In various forms, the at least one signal adjustment value includes a lead time value.

[0024] In various forms, the feedforward module computes the at least one signal adjustment value as the lead time value based on a computed integral square deviation.

[0025] In various forms, the sample data is associated with a batch type data and stored as associated data in the data storage device.

[0026] In various forms, the time period is predefined based on a total batch time.

[0027] In another form, a computer-readable storage device storing instructions which, when executed by one or more processors, cause the one or more processors to control a heater of an etching system. The one or more processors control the heater by: generating first control signals to the heater based on setpoint temperature data; storing sample data associated with the first control signals generated over a time period; computing at least one signal adjustment value based on the sample data; applying the at least one signal adjustment value to subsequent control signals to provide adjusted control signals; and generating the adjusted control signals to the heater.

[0028] Further areas of applicability will become apparent from thedescription 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.DRAWINGS

[0029] In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

[0030] FIG. 1 is a functional block diagram of a dry etching system comprising a heater control system in accordance with various forms of the present disclosure;

[0031] FIG. 2 is a dataflow diagram illustrating the heater control system of the heater system of FIG. 1 in accordance with various forms of the present disclosure;

[0032] FIG. 3 is a graph illustrating exemplary control signal data generated by the heater control system in accordance with various forms of the present disclosure; and

[0033] FIGS. 4, 5 and 6 are flowcharts illustrating a heater control method that may be performed by the heater control system of FIG. 2 in accordance with various forms of the present disclosure.

[0034] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.DETAILED DESCRIPTION

[0035] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0036] With reference now to FIG. 1 , an exemplary etching system 100 is shown having a heater system shown generally at 102 that is controlled by a heater control system shown generally at 104 in accordance with the present disclosure. The etching system 100 generally includes a processing chamber 106, a support structure shown generally at 108, an etching device 110, a gas supply system 111 , an exhaust system 112, and one or more control modules 116.

[0037] The processing chamber 106 provides a space S for performing an etching process on an object, referred to herein as a target object 118. In various forms, the etching device 110 is a dry or semi dry etching device such as, but not limited to, a plasma etching device that performs the etching process by producing a plasma from a process gas by exciting the process gas using a high frequency electric field. In various forms, the target object 118 can be a wafer of a semiconductor device. As can be appreciated, the plasma etching device and the wafer are provided as examples, as other dry etching devices and target objects may be implemented in the etching system 100 in accordance with the present disclosure.

[0038] The processing chamber 106 is configured to enclose the target object 118 within the space S. In various forms, the support structure 108 supports and / or secures the target object 118 within the space S. The support structure 108 and / or the etching device 110 are configured to move relative to one another to allow for etching or removal of material from a top surface of the target object 118 according to a desired pattern.

[0039] The gas supply system 111 selectively supplies a cooling gas, such as Helium, to the space S to cool the target object 118. The exhaust system 112 selectively releases the gas from the space S. The control module 116 controls the generation of plasma by the etching device 110, the movement of the etching device 110 and / or the support structure 108, the supply of the cooling gas to the processing chamber 106 by the gas supply system 111 , and / or the exhaust of gases from the processing chamber 106 by the exhaust system 112 according to methods and systems of the etching process.

[0040] In various forms, the support structure 108 includes a support plate 120 coupled to a shaft 122. The support plate 120 is configured to support the target object 118 in a horizontal position relative to the etching device 110. The shaft 122 is configured with a transition apparatus 124 that is configured for mounting and sealing the shaft 122 to a lower floor of the processing chamber 106. In various forms, the shaft 122 is hollow and configured to receive electrical components such as, but not limited to, power pins, any grid, antenna, and / or ground plane electrical power connections or wires, and any gas or vacuum connections associated with the gas supply system 111 and / or exhaust system 112.

[0041] In various forms, the support plate 120 includes a heater 126 of the heater system 102. The heater 126 is configured to provide heat such that adesired setpoint temperature of the target object 118 resting on the support plate 120 is maintained during the etching process. The heater 126 includes at least one resistive element that is controlled to generate heat. In various forms, the resistive element can be in the form of a wire or other geometrical shape (e.g., sheets, films, etc.) that is straight, coiled, wound, etc. and embedded within an Aluminum Nitride (AIN) sintered (or other material) ceramic bottom plate. The resistive element is enclosed between to plates to provide the support plate 120. As can be appreciated, the heater 126 may include two or more resistive elements that each are controlled to generate heat to a respective zone of the support plate 120. As can be appreciated, any number of resistive elements may be included in the heater system 102 with various different configurations to provide various different zones as the disclosure is not limited to the present examples.

[0042] The heater system 102 further includes a heater control module 128 and one or more sensors 130. The heater control module 128 may be included as part of the control module 116 or as a separate module as shown. The heater control module 128 is communicatively coupled to the heater 126 and is configured to control the heat provided by the heater 126. The one or more sensors 130 sense observable conditions of the heater system 102 (e.g., temperature data) and provide sensor data as feedback data to the heater control module 128.

[0043] In various forms, the heater control module 128 generally includes at least an input device 130, an output device 132, at least one processor 134 and memory 136 and, optionally, a communication device 138. In various forms, the input device 130 is configured to receive the sensed data from the sensor 130 and / or other devices such as, but not limited to, user input devices (not shown). Similarly, the output device 132 is configured to provide temperature data 142 or other data that may be used by one or more evaluation devices to evaluate the performance of the heater system 102.

[0044] In various forms, the communication device 138 is configured to receive data and / or communicate data such as temperature data 142 or other performance data to a remote system or other entity for further evaluation by way of a wired or wireless communication protocol.

[0045] In various forms, the processor 134 can be any custom made or commercially available processor, a central processing unit (CPU), an auxiliary processor among several processors associated with the processor, a semiconductorbased microprocessor (in the form of a microchip or chip set), a macro processor, any combination thereof, or generally any device for executing instructions. Although only one processor 134 is shown, various forms of the heater control system 104 can include any number of processors 134 that communicate over any suitable communication medium or a combination of communication mediums. The processors 134 cooperate to process sensor data, perform logic, calculations, methods, processes and / or algorithms, generate control signals to the heater 126, and / or communicate the temperature data and / or other performance data via the output device 132 and / or the communication device 138.

[0046] In various forms, the memory 136 may include volatile and nonvolatile storage in read-only memory (ROM), random-access memory (RAM), and keep-alive memory (KAM), for example. KAM is a persistent or non-volatile memory that may be used to store various operating variables while the processor 134 is powered down. The memory 136 may be implemented using any of a number of known memory devices such as PROMs (programmable read-only memory), EPROMs (electrically PROM), EEPROMs (electrically erasable PROM), flash memory, or any other electric, magnetic, optical, or combination memory devices capable of storing data, some of which represent executable instructions, used by the processor 134 in performing the methods and / or processes of the heater control system 104.

[0047] In various forms, the instructions, when executed by the processor 134, perform logic, calculations, methods, and / or algorithms for measuring and processing sensor data, and generating control signals for controlling the heater 126 using a feedback loop and feed forward control, as will be described further below.

[0048] In various forms, the memory 136 further includes a data storage device 140 that stores predefined data such as models, measured data, and / or predicted data associated with the heater system 102 and / or the etching system 100 (e.g., data associated with the resistive element, the configured zones, and / or the conditions associated with the processing environment of the heater system 102). As will be discussed herein, the stored data is used by the heater control system 104 to generate the control signals for controlling the heater 126 using a feedback loop and a feed forward control as disclosed herein. As such, the heater system 102 is configured to provide improved temperature control by the heater 126 during the etching process performed by the etching system 100.

[0049] With reference now to FIG. 2 and with continued reference to FIG. 1 , a dataflow diagram illustrates various forms of the heater control module 128 in accordance with the present disclosure. That is, suitable software and / or hardware components of the heater control module 128 (e.g., the processor 134 and the memory 136) are utilized to control the temperature provided by the heater system 102. In various forms, inputs to the heater control module 128 may be received from the input device 130, received from the communication device 138, and / or determined, modeled, or pre-processed by other sub-modules (not shown) within the heater control module 128.

[0050] In various forms, the instructions of the heater control module 128 may be organized by function or system into sub-modules and datastores. For example, as shown in FIG. 2, the heater control module 128 can be configured to include a feedback module 202, a data sampling module 204, a feed forward module 206, a signal generator module 208, and a sample data datastore 210.

[0051] In various forms, the feedback module 202 receives as input setpoint temperature data 212, and feedback temperature data 214. The setpoint temperature data 212 indicates a desired setpoint temperature for operating the heater 126. The desired setpoint temperature may be predefined based on a batch type and / or based on one or more stages of the batch type. The feedback temperature data 214 includes measured temperature data sensed by the sensor 130 associated with the heater 126.

[0052] The feedback module 202 generates control data 216 used for controlling the heater 126 based on the setpoint temperature data 212, and the feedback data 214. For example, the feedback module 202 determines control data 216 based on the desired setpoint temperature. In various forms, when the feedback temperature data 214 is not yet available, the feedback module 202 generates the control data 216 based only on the desired setpoint temperature.

[0053] When the feedback temperature data 214 is available, the feedback module 202 applies a correction value to the control data based on the measured temperature data and generates the corrected control data as the control data 216. For example, the feedback module 202 computes an error value as the difference between the desired setpoint temperature and the measured temperature and determines the correction value based on the computed error value. In various forms, the feedback module 202 computes the correction value based on a weightedsum of a proportional term, an integral term, and a derivative term associated with the computed error.

[0054] In various forms, the data sampling module 204 receives as input batch type data 218 and control signal data 220. The batch type data 218 indicates a type that is based on the target object 118 to be etched, and / or attributes of the etching materials or systems to be used in the etching process. The control signal data 220 is the signal data generated by the signal generator module 208 based on the control data 216. The data sampling module 204 accumulates the control signal data 220 over a defined time period. In various forms, the defined time period is based on a total time to etch the target object, referred to as a batch time (e.g., a period less than the total time, such as the first minute or other amount of time). Once control signal data 220 has been accumulated, the data sample module 204 associates the accumulated control signal data 220 with the batch type and stores the associated data as sample data 222 in the sample data datastore 210.

[0055] In various forms, the feedforward module 206 receives as input setpoint temperature data 212, the feedback temperature data 214, and the sample data 222 from the sample data datastore 210, once it is available. The feedforward module 206 determines feedforward signal adjustment values such as a lead time value and / or an attenuation gain value based on the received data 212, 214, and 222. The feedforward module 206 generates adjustment data 223 such as lead time data 224 and attenuation gain data 226 based on the determinations.

[0056] For example, the feedforward module 206 computes a lead time value based on a determined response time of the process or an oscillation period of the process disturbances. For example, the feedforward module 206 initializes the lead time value to thirty percent (or some other value) of an integral time constant (Tl) of tuning of the feedback module, or ten percent (or some other value) of an oscillation period produced by the process disturbance indicated in the sample data 222. Optionally, thereafter, the feedforward module 206 iteratively updates the initialized lead time value based on a computed integral square deviation of performance values:ISD = Integral Square Deviation = f (SP — PV)2dt, (1) where SP represents the setpoint temperature value, and PV represents the measured temperature value.

[0057] In another example, the feedforward module 206 computes an attenuation gain value as a percent gain of the feedforward component with a range from zero percent to one hundred percent (e.g., attenuation gain of zero percent removes the feedforward adjustment, 100 percent maintains the current feedforward). The feedforward module 206 initializes the attenuation gain value to, for example, fifty percent, and then iteratively adjusts the initialized value based on a computed integral square deviation of the performance values (e.g., as shown in equation 1 ). In various forms, the feedforward module 206 applies the computed phase shift value and the computed attenuation gain value to the sample data 222 to provide the adjustment data 223.

[0058] In various forms, the signal generator module 208 receives as input the control data 216, and the adjustment data 223 including the lead time data 224, and / or the attenuation gain data 226. The signal generator module 208 generates the heater control signal data 220 to the heater 126 by adjusting the control data 216 based on the lead time value, and / or the attenuation gain value, when available. For example, the signal generator module 208 adds the adjusted sample data 223 to the control data 216 to generate control signal data 220 for controlling the heater system 102.

[0059] Referring now to FIG. 3 and within continued reference to FIGS. 1-2, a graph 300 illustrates temperature data sensed by, for example, the sensor 130. The graph 300 may be provided as temperature data 142 for heater performance analysis as discussed above. The graph 300 includes time illustrated along the x-axis 302 and temperature illustrated along the y-axis 304. The setpoint temperature is shown as 310. The temperature variations from the setpoint temperature 310 due to temperature disturbances introduced by the etching system 100 are reduced in the plotted temperature data 306 (when the feedforward correction is applied) from the plotted temperature data 308 (when the feedforward correction is not applied).

[0060] Referring now to FIGS. 4, 5, 6, and 7, and with continued reference to FIGS. 1-3, flowcharts illustrate processes 400, 500, 600, 700 that can be performed by, for example, the modules of the heater control module 114 of the heater system 102 when performing or prior to performing an etching process by the etching system 100 in accordance with the present disclosure. As can be appreciated in light of the disclosure, the order of operation within the process is not limited to the sequential execution as illustrated in the figures but may be performed in one or morevarying orders as applicable and in accordance with the present disclosure. In various embodiments, the processes 400, 500, 600, 700 can be scheduled to run independently or in a defined order based on one or more predetermined events associated with the etching process as performed by the etching system 100.

[0061] In one form, the process 400 is referred to as a commissioning process and is used to establish the adjustment parameters 223.

[0062] For example, one or more steps of the process 400 may be performed as a separate process offline, using one or more models associated with the etching system 100 that predicts the thermal response of the etching system 100 and provides the feedback temperature data. In another example, one or more steps of the process 440 may be performed as a separate process using the heater system 102 to provide the feedback temperature data prior to actual production. In such examples, the sample data obtained offline is associated with the batch type and stored in the datastore for use in a real-time or production etching process performed by the etching system 100.

[0063] In various forms, any tuning parameters associated with the feedback module 202 have already been established.

[0064] In various forms, the process 400 may begin at 405. The setpoint temperature data is received for the current batch type at 410. It is determined whether feedback temperature data is received at 420. If feedback temperature data is not yet received at 420, the control data is generated based on the setpoint temperature data at 430. If, however, feedback temperature data is received at 420, the control data is generated based on the setpoint temperature data, the measured temperature data, and proportional, integral, and / or derivative values at 440.

[0065] Thereafter, it is determined whether sample data has been stored for a defined time period for the current batch type at 450. If sample data has not been stored at 450, a control signal is generated based on the control data to control the heater at 460 and the control data is stored as the sample data for the current batch type at 470. If the batch is not complete at 480, the process continues at 410 where the setpoint temperature data is received.

[0066] Once the sample data has been stored over the defined time period for the current batch type at 450, the adjustment values are determined. For example, the lead time value is computed from the stored sample data at 482; and the attenuation value is computed from the stored sample data at 484.

[0067] Thereafter, the lead time value and the attenuation value are then applied to the control data using adjusted sample data to provide adjusted control data at 486 and the control signal is generated based on the adjusted control data at 488.

[0068] Once it is determined that the batch is complete at 480, the process 400 may end at 490.

[0069] As can be appreciated, in various forms, the process 400 may be followed by a production process. In other words, the production process, when executed, performs steps 486, 488 to adjust the control data using the adjusted sample data during the etching process.

[0070] In various forms, the process 500 is referred to as part of the commissioning process to determine the lead time value of the adjustment parameters 223. In various forms, the process 500 may begin at 505. The lead time data is received at 510 and evaluated at 512. If the lead time has not yet been initialized at 512, the iteration value and the limits are set at 514 and the lead time is initialized with the integral time constant or the determined oscillation period at 516.

[0071] Once the lead time has been initialized at 512, a baseline integral square deviation ISD0 is computed at 518, an increased integral square deviation is computed ISD1 at 520, and a decreased integral square deviation is computed ISD2 at 522. Thereafter, the computed integral square deviations are compared at 524.

[0072] If the base line ISD is less than the increased ISD and the baseline ISD is less than the decreased ISD at 524, the better of the ISD1 and the ISD2 is selected as the new baseline ISD at 526 and the process 500 continues at 520. If, however, baseline ISD is greater than the decreased ISD or the baseline ISD is greater than the increased ISD at 5524, the iteration percent is adjusted at 528.

[0073] Thereafter, the iteration percent is evaluated at 530. If the iteration percent has reached a minimum threshold at 530, the lead time is set at 534 and the process 500 may end at 536. If the iteration percent has not reached the minimum threshold at 530, however, the lead time has reached a low threshold or a high threshold at 532, the lead time is set at 534 and the process 500 may end at 536.

[0074] If, however, the lead time has not reached the low threshold or the high threshold at 532, the process 500 continues at 518 where a new baseline ISD is computed.

[0075] In various forms, the process 600 is referred to as part of the commissioning process to determine the attenuation gain value of the adjustmentparameters 223. In various forms, the process 600 may begin at 605. The attenuation gain data is received at 610 and evaluated at 612. If the attenuation gain has not yet been initialized at 612, the iteration value and the limits are set at 614 and the attenuation gain is initialized with a predefined percent (e.g., fifty percent) at 616.

[0076] Once the attenuation gain has been initialized at 612, a baseline integral square deviation ISD0 is computed at 618, an increased integral square deviation is computed ISD1 at 620, and a decreased integral square deviation is computed ISD2 at 622. Thereafter, the computed integral square deviations are compared at 624.

[0077] If the base line ISD is less than the increased ISD and the baseline ISD is less than the decreased ISD at 624, the better of the ISD1 and the ISD2 is selected as the new baseline ISD at 626 and the process 600 continues at 620. If, however, baseline ISD is greater than the decreased ISD or the baseline ISD is greater than the increased ISD at 624, the iteration percent is adjusted at 628.

[0078] Thereafter, the iteration percent is evaluated at 630. If the iteration percent has reached a minimum threshold at 630, the attenuation gain is set at 634 and the process 600 may end at 636. If the iteration percent has not reached the minimum threshold at 630, however, the attenuation gain has reached a low threshold or a high threshold at 632, the attenuation gain is set at 634 and the process 600 may end at 636.

[0079] If, however, the attenuation gain has not reached the low threshold or the high threshold at 632, the process 600 continues at 618 where a new baseline ISD is computed.

[0080] Unless otherwise expressly indicated herein, all numerical values indicating mechanical / thermal properties, compositional percentages, dimensions and / or tolerances, or other characteristics are to be understood as modified by the word “about” or "approximately" in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.

[0081] As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

[0082] In this application, the term “controller” and / or “module” may refer to, be part of, or include: an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor (shared, dedicated, or group) that executes code; a memory (shared, dedicated, or group) that stores code executed by the processor; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip.

[0083] The term memory is a subset of the term computer-readable medium. The term computer-readable medium, as used herein, does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium may therefore be considered tangible and non-transitory. Non-limiting examples of a non-transitory, tangible computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask readonly 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 magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).

[0084] The apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general-purpose computer to execute one or more particular functions embodied in computer programs. In various forms, the functional blocks, flowchart components, and other elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer.

[0085] The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance 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

CLAIMSWhat is claimed is:1 . A method for controlling a heater of an etching system, comprising: generating first control signals to the heater based on setpoint temperature data; storing, in a data storage device, sample data associated with the first control signals generated over a time period; computing, by a processor, at least one signal adjustment value based on the sample data; applying, by the processor, the at least one signal adjustment value to subsequent control signals to provide adjusted control signals; and generating the adjusted control signals to the heater.

2. The method of claim 1 , wherein the at least one signal adjustment value includes an attenuation gain value.

3. The method of claim 2, wherein the computing the at least one signal adjustment value comprises computing the attenuation gain value based on a computed integral square deviation.

4. The method of claim 1 , wherein the at least one signal adjustment value includes a lead time value.

5. The method of claim 4, wherein the computing the at least one signal adjustment value comprises computing the lead time value based on a computed integral square deviation.

6. The method of claim 4, wherein the at least one signal adjustment value further includes an attenuation gain value.

7. The method of claim 1 , further comprising associating with the sample data, batch type data and storing the batch type data in the data storage device.

8. The method of claim 7, wherein the batch type data is based on one or more of a target object processed by the etching system, and an attribute of the etching system.

9. The method of claim 1 , wherein the time period is predefined based on a total batch time.

10. The method of claim 9, wherein the time period is less than the total batch time.11 . The method of claim 1 , wherein the generating the first control signals is further based on feedback temperature data.

12. The method of claim 11 , wherein the generating the first control signals is further based on at least one of a proportional term, an integral term, and a derivative term determined from the setpoint temperature data and the feedback temperature data.

13. A system for controlling a heater of an etching system, the system comprising: a data storage device that stores sample data associated with first control signals generated over a time period; a feedback module configured to, by a processor, generate control data based on a desired setpoint temperature; a feedforward module configured to, by a processor, compute at least one signal adjustment value based on the sample data; and a signal generator module configured to, by a processor, apply the at least one signal adjustment value to the control data to provide adjusted control signals, and generate the adjusted control signals to the heater.

14. The system of claim 13, wherein the at least one signal adjustment value includes an attenuation gain value.

15. The system of claim 14, wherein the feedforward module computes theat least one signal adjustment value as the attenuation gain value based on a computed integral square deviation.

16. The system of claim 13, wherein the at least one signal adjustment value includes a lead time value.

17. The system of claim 16, the feedforward module computes the at least one signal adjustment value as the lead time value based on a computed integral square deviation.

18. The system of claim 13, wherein the sample data is associated with a batch type data and stored as associated data in the data storage device.

19. The system of claim 13, wherein the time period is predefined based on a total batch time.

20. A computer-readable storage device storing instructions which, when executed by one or more processors, cause the one or more processors to control a heater of an etching system by: generating first control signals to the heater based on setpoint temperature data; storing sample data associated with the first control signals generated over a time period; computing at least one signal adjustment value based on the sample data; applying the at least one signal adjustment value to subsequent control signals to provide adjusted control signals; and generating the adjusted control signals to the heater.

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