SUBSTRATE PROCESSING SYSTEMS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63/336,821 , filed on April 29, 2022. The entire disclosure of the above application is incorporated herein by reference.

FIELD

[0002] The present disclosure relates to substrate processing systems, and more particularly to automatic gap compensation between a gas delivery device and a substrate in a substrate processing system.

BACKGROUND

[0003] The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0004] Substrate processing systems may be used to treat substrates such as semiconductor wafers. The substrate treatments may include deposition, etching, cleaning and other treatments. Example processes that may be performed on a substrate include, but are not limited to, chemical vapor deposition (CVD), atomic layer deposition (ALD), conductor etch, rapid thermal processing (RTP), ion implant, physical vapor deposition (PVD), and/or other etch, deposition, or cleaning processes.

[0005] A substrate may be arranged on a substrate support, such as a pedestal, an electrostatic chuck (ESC), etc. in a processing chamber of the substrate processing system. During processing, gas mixtures including one or more precursors may be introduced into the processing chamber using a showerhead (or other gas delivery device) and plasma may be used to initiate chemical reactions.

[0006] The substrates delivered to the processing chamber may have variable thicknesses. Furthermore, the thickness of the substrates may vary during processing in response to increased process temperatures and/or changes in materials due to deposition or etching. In some examples, the shape of the substrate may change during processing. In other words, a gap between the showerhead (or other gas delivery device) and the substrate may vary during processing. The treatment performed by the substrate processing system may be sensitive to variations in the gap, which may cause substrate non-uniform ities to occur.

SUMMARY

[0007] A gap compensation system comprises a light source configured to transmit light toward a gap during processing of the substrate. The gap is located between a substrate arranged on a substrate support in a processing chamber and a component in the processing chamber arranged adjacent to the substrate. A light sensor is configured to receive a portion of the light and to generate a measurement signal based on a measured characteristic of the portion of the light. An actuator is configured to adjust a height of at least one of the substrate support and the component. A controller includes a gap compensation module configured to cause the light source to transmit the light during a plurality of sampling intervals; during each of the plurality of sampling intervals, receive a plurality of measurement signals; at least one of: convert the plurality of measurement signals to a plurality of gap measurements and apply a function to the plurality of gap measurements corresponding to each of the sampling intervals; apply a function to the plurality of measurement signals corresponding to each of the sampling intervals and convert an output of the function to a sampling interval gap measurement; and selectively adjust the gap using the actuator during two or more of the sampling intervals based on a predetermined gap and at least one of the output of the function and the sampling interval gap measurement.

[0008] In other features, the controller is configured to determine a difference between the predetermined gap and the at least one of the output of the function and the sampling interval gap measurement. The controller is configured to adjust the gap using the actuator based on a product of the difference and a predetermined gain value that is greater than 0 and less than 1 .

[0009] In other features, the component comprises a gas delivery device. The gas delivery device is selected from a group consisting of a showerhead, a gas distribution plate and an electrode. The light source includes a laser and the measured characteristic comprises a beam intensity of laser light received by the light sensor. The light sensor comprises a charge coupled device. [0010] In other features, the light source and the light sensor are arranged on opposite sidewalls of the processing chamber and the beam intensity of the laser corresponds to a portion of the laser that passes through the gap and is received by the light sensor. The light source and the light sensor are arranged on the same side of the processing chamber and the beam intensity of the laser corresponds to a portion of the laser that is reflected.

[0011] In other features, the function is selected from a group consisting of an average, a mid-average, a moving average, a minimum value, and a maximum value. Radio frequency (RF) plasma is generated during processing of the substrate and wherein the plurality of sampling intervals occur after the RF plasma is struck and before the RF plasma is extinguished.

[0012] In other features, radio frequency (RF) plasma is generated during processing of the substrate. At least one of the plurality of sampling intervals occurs before the RF plasma is struck. Others of the plurality of sampling intervals occur after the RF plasma is struck and before the RF plasma is extinguished.

[0013] A method for automatically compensates a gap between a substrate arranged on a substrate support in a processing chamber and a component in the processing chamber arranged adjacent to the substrate. The method comprises causing a light source to transmit light toward the gap during a plurality of sampling intervals. During each of the plurality of sampling intervals, the method includes receiving a plurality of measurement signals from a light sensor. The method includes at least one of converting each of the plurality of measurement signals to a plurality of gap measurements and applying a function to the plurality of gap measurements corresponding to each of the sampling intervals, and applying a function to the plurality of measurement signals corresponding to each of the sampling intervals and converting an output of the function to a sampling interval gap measurement. The method includes selectively adjusting the gap using an actuator configured to adjust a height of at least one of the substrate support and the component during two or more of the sampling intervals based on a predetermined gap and at least one of the output of the function and the sampling interval gap measurement.

[0014] In other features, the method includes determining a difference between the predetermined gap and the at least one of the output of the function and the sampling interval gap measurement. The method includes adjusting the gap using the actuator based on a product of the difference and a predetermined gain value that is greater than 0 and less than 1 .

[0015] In other features, the component comprises a gas delivery device. The gas delivery device is selected from a group consisting of a showerhead, a gas distribution plate and an electrode. The light source includes a laser and the light sensor measures a beam intensity of laser light received by the light sensor. The light sensor comprises a charge coupled device.

[0016] In other features, the method includes arranging the light source and the light sensor on opposite sidewalls of the processing chamber, wherein the beam intensity of the laser corresponds to a portion of the laser that passes through the gap and is received by the light sensor.

[0017] In other features, the method includes arranging the light source and the light sensor on the same side of the processing chamber, wherein the beam intensity of the laser corresponds to a portion of the laser that is reflected.

[0018] In other features, the function is selected from a group consisting of an average, a mid-average, a moving average, a minimum value, and a maximum value.

[0019] In other features, radio frequency (RF) plasma is generated during processing of the substrate and wherein the plurality of sampling intervals occur after the RF plasma is struck and before the RF plasma is extinguished.

[0020] In other features, radio frequency (RF) plasma is generated during processing of the substrate. At least one of the plurality of sampling intervals occurs before the RF plasma is struck. Others of the plurality of sampling intervals occur after the RF plasma is struck and before the RF plasma is extinguished.

[0021] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: [0023] FIG. 1 is a functional block diagram of an example substrate processing system including a substrate support according to the present disclosure;

[0024] FIG. 2 is an example of a processing chamber including a light source and a light sensor arranged to measure a gap between a showerhead (or other gas delivery device) and a substrate according the present disclosure;

[0025] FIG. 3 is another example of a processing chamber including a light source and a light sensor arranged to measure a gap between a showerhead (or other gas delivery device) and a substrate according the present disclosure;

[0026] FIG. 4 is a graph illustrating an example of a measured gap as a function of sensed light according to the present disclosure;

[0027] FIGs. 5A to 5C are graphs illustrating examples of the gap during passive and/or active gap compensation according to the present disclosure;

[0028] FIG. 6 is an example of a method for calibrating a linear equation for the light sensor according to the present disclosure;

[0029] FIG. 7 is an example of a gap compensation method for passively compensating a gap between a showerhead (or other gas delivery device) and a substrate according the present disclosure; and

[0030] FIG. 8 is an example of a gap compensation method for actively compensating a gap between a showerhead (or other gas delivery device) and a substrate according the present disclosure.

[0031] In the drawings, reference numbers may be reused to identify similar and/or identical elements.

DETAILED DESCRIPTION

[0032] As the complexity of substrate processing increases due to technologies such as bonded wafers, 3D stacking, 3D NAND memory, etc., substrate thickness variation (i.e. , substrate-to-substrate variation) also increases. When the substrates that are delivered to a processing chamber for a substrate treatment have variable thicknesses, a gap between the showerhead (or other gas delivery device) varies. Some processes have a high sensitivity to variations in the gap. Accordingly, variations in the substrate thickness may cause process non-uniform ities and changes to both process behavior and results. [0033] Systems and methods according to the present disclosure use a light source such as laser or other light source and a light sensor to measure a gap between a substrate and a showerhead (or other gas delivery device). A controller according to the present disclosure automatically adjusts the gap by changing a height of the substrate support or the showerhead (or other gas delivery device) in response to the gap measurement to compensate for variations in the gap due to substrate thickness variations or other causes. In other words, the controller measures the gap between facing surfaces of the substrate and the showerhead (or other gas delivery device) and adjusts the gap to a predetermined gap.

[0034] In some examples, passive gap compensation is performed before initiating the process. For example, for plasma-based processes, the passive gap compensation is performed prior to turning on the radio frequency (RF) plasma. Advantages of passive gap compensation include less interference and noise due to light measurements made while RF plasma is on.

[0035] In other examples, active gap compensation is performed during the process. In other words, gap compensation is performed during processing (e.g. for plasma-based processes, after RF plasma is turned on). Advantages of active gap compensation include providing a stable gap during the entire process rather than limiting gap compensation to the start of the process. In some examples, active gap compensation is performed after passive gap compensation described above. In some examples, the gap is measured multiple times during a sampling period and an average (or another function) of the gap measurements is used to reduce noise due to the RF plasma or other factors.

[0036] One or more characteristics of the light (e.g., a beam intensity) is proportional to the gap and/or the substrate thickness. Accordingly, process parameters may be adjusted to compensate for any variations in the gap, which accounts for substrate thickness variations.

[0037] FIG. 1 shows a substrate processing system 100 including a processing chamber 102 that encloses components of the substrate processing system 100 and contains RF plasma. The processing chamber 102 includes an upper electrode 104 and a substrate support 106, which may be an electrostatic chuck (ESC). During operation, a substrate 108 is arranged on the substrate support 106. While a specific example of the substrate processing system 100 and processing chamber 102 are shown as an example, the principles of the present disclosure may be applied to other types of substrate processing systems and chambers, such as a substrate processing system that uses remote plasma generation and delivery (e.g., using a plasma tube, a microwave tube), etc.

[0038] A gas distribution device 111 introduces and distributes process gases. For example only, the upper electrode 104 may be combined with a showerhead 109 (acting as the gas distribution device 111 ). The showerhead 109 may include a stem portion including one end connected to a top surface of the processing chamber 102. A base portion is generally cylindrical, includes a gas plenum and extends radially outwardly from an opposite end of the stem portion at a location that is spaced from the top surface of the processing chamber 102. A substrate-facing surface or faceplate of the base portion of the showerhead 109 includes holes through which process gas or purge gas flows. Alternately, the upper electrode 104 may include a conducting plate and the process gases may be introduced in another manner.

[0039] The substrate support 106 includes a conductive baseplate 110 that acts as a lower electrode. The baseplate 110 supports a top plate 112, which may be formed of ceramic. In some examples, the top plate 112 may include one or more heating layers, such as a ceramic multi-zone heating plate. The one or more heating layers may include one or more heating elements, such as conductive traces, as further described below.

[0040] A bond layer 114 is disposed between and bonds the top plate 112 to the baseplate 110. The baseplate 110 may include one or more coolant channels 116 for flowing coolant through the baseplate 110. In some examples, the substrate support 106 may include an edge ring 118 arranged to surround an outer perimeter of the substrate 108.

[0041] An RF generating system 120 generates and outputs an RF voltage to one of the upper electrode 104 and the lower electrode (e.g., the baseplate 110 of the substrate support 106). The other one of the upper electrode 104 and the baseplate 110 may be DC grounded, AC grounded or floating. For example only, the RF generating system 120 may include an RF voltage generator 122 that generates the RF voltage that is fed by a matching and distribution network 124 to the baseplate 110. In other examples, the RF voltage is provided to the upper electrode 104. In other examples, the plasma may be generated inductively or remotely. Although, as shown for example purposes, the RF generating system 120 corresponds to a capacitively coupled plasma (CCP) system, the principles of the present disclosure may also be implemented in other suitable systems, such as transformer coupled plasma (TCP) systems, CCP cathode systems, remote microwave plasma generation and delivery systems, etc.

[0042] A gas delivery system 130 includes one or more gas sources 132-1 , 132-2, ... , and 132-N (referred to collectively as gas sources 132), where N is an integer greater than zero. The gas sources supply one or more gas mixtures. The gas sources may also supply purge gas. Vaporized precursor may also be used. The gas sources 132 are connected by valves 134-1 , 134-2, ... , and 134-N (referred to collectively as valves 134) and mass flow controllers 136-1 , 136-2, ... , and 136-N (referred to collectively as mass flow controllers 136) to a manifold 140. A second set of valves (not shown) may be arranged between the mass flow controllers 136 and the manifold 140. An output of the manifold 140 is fed to the processing chamber 102. For example only, the output of the manifold 140 is fed to the showerhead 109.

[0043] A temperature controller 142 may be connected to heating elements, such as thermal control elements (TCEs) 144 arranged in the top plate 112. For example, the heating elements may include, but are not limited to, macro heating elements corresponding to respective zones in a multi-zone heating plate and/or an array of micro heating elements disposed across multiple zones of a multi-zone heating plate. The temperature controller 142 may be used to control the heating elements to control a temperature of the substrate support 106 and the substrate 108.

[0044] The temperature controller 142 may communicate with a coolant assembly 146 to control coolant flow through the channels 116. For example, the coolant assembly 146 may include a coolant pump and reservoir. The temperature controller 142 operates the coolant assembly 146 to selectively flow the coolant through the channels 116 to cool the substrate support 106.

[0045] A valve 150 and pump 152 may be used to evacuate reactants from the processing chamber 102. A controller 160 may be used to control components of the substrate processing system 100. One or more robots 170 may be used to deliver substrates onto, and remove substrates from, the substrate support 106.

[0046] The processing chamber 102 according to the present disclosure includes a light source 180 arranged to transmit a light signal such as a laser through the processing chamber 102 and through a gap between the substrate 108 and the showerhead 109. A light sensor 182 is arranged on a side of the processing chamber 102 opposite the light source 180 to measure received light. The gap value in a vertical direction is proportional to the measured light. Once the value of the gap is determined, the value of the gap can be adjusted by moving either the showerhead (or other gas delivery device) and/or the substrate support to provide a predetermined gap.

[0047] FIG. 2 shows an example of a processing chamber 200 including a light source 204 and a light sensor 208 according the present disclosure. For example, the light source 204 and the light sensor 208 are arranged on opposite sidewalls of the processing chamber 200. A substrate 212 is arranged on a substrate support 216 below a component such as a showerhead 220 (or other gas delivery device), a central insulator, etc. For example, the substrate support 216 includes a baseplate 224 and an upper plate or layer 228 (e.g., a ceramic layer) and the substrate 212 is arranged on the upper plate 228. A gap TG (corresponding to a width of the gap in a vertical direction) is defined between the showerhead 220 and the substrate 212.

[0048] In this example, the light source 204 is configured to transmit a light signal 232 (e.g., a laser or other suitable light signal) through the gap between the substrate 212 and the showerhead 220 toward the light sensor 208. For example, the light source 204 is configured to transmit the light signal 232 responsive to control signals generated by a controller 236 including a gap compensation module 238. In some examples, the light signal 232 is transmitted while RF plasma is present in the processing chamber 200.

[0049] The light sensor 208 senses/receives the light signal 232 and provides a signal to the controller 236 indicative of characteristics of the light signal 232. For example, the signal provided to the controller 236 may be indicative of a beam intensity of the light signal 232 as measured by the light sensor 208. The gap compensation module 238 is configured to calculate a thickness of the substrate 212 and/or a width of the effective gap based on the measured characteristics of the light signal 232. Although the beam intensity is provided as one example, other characteristics of the light signal 232 that may be measured with a suitable sensor include, but are not limited to, energy, width, etc. In some examples, a charge coupled device (CCD) sensor may be used.

[0050] For example only, the beam intensity of the light signal 232 may depend upon a thickness of the light signal 232 that is permitted to pass through the effective gap. In other words, if the substrate 212 is thicker or the effective gap is otherwise reduced (e.g., due to manufacturing tolerances of the showerhead 220, the baseplate 224, the upper plate 228, etc., contraction and expansion of components over time, component wear, etc.), less of the light signal 232 will be able to pass through the gap toward the light sensor 208. Conversely, if the substrate 212 is thinner or the effective gap is otherwise increased, more of the light signal 232 will be able to pass through the gap. Accordingly, a laser intensity I has a proportional relationship with the gap TG and an inversely proportional relationship with a substrate thickness. In some examples, the intensity may correspond to the width of the laser beam and/or the amplitude of the coherent light.

[0051] A signal transmitted by the light sensor 208 to the controller 236 is proportional to the measured intensity. For example, the light sensor 208 may be configured to generate a measurement signal having a voltage indicative of the intensity. The gap compensation module 238 is configured to calculate the gap and/or the substrate thickness based on the measured intensity. In some examples, the controller 236 may store data (e.g., e.g., calibration data stored in a lookup table) or a linear equation that correlate intensity to the gap and/or to the substrate thicknesses. The data may include an initial, calibrated gap value and corresponding laser intensity measured during manufacturing, servicing, etc. Calibration data may include intensity measurements for a nominal (e.g., ideal) gap with and without a substrate (e.g., a substrate having a known nominal or expected thickness).

[0052] The gap compensation module 238 is configured to adjust a position of one or more components of the processing chamber 200 based on the measured gap (e.g. using one or more actuators 240 and/or 244). For example, deposition rates may vary in response to the gap (which is affected by substrate thickness). More specifically, deposition rates may decrease in some portions of a substrate (e.g., as indicated by substrate radius) as the gap decreases and increase as the gap increases. In other words, deposition rates may be proportional to gap width and inversely proportional to substrate thickness. For example only, a deposition rate for a first substrate thickness and corresponding first gap may be less than a deposition rate for a second substrate thickness and corresponding second gap, where the first substrate thickness is greater than the first substrate thickness and the first gap is less than the second gap. Although described with respect to deposition rates, the principles of the present disclosure may also be applied to etch rates.

[0053] FIG. 3 shows another example processing chamber 400 according to the present disclosure. In this example, the processing chamber 400 includes a light source/light sensor 404. A substrate 412 is arranged on a substrate support 416 below a showerhead 420. An effective gap TG is defined between the showerhead 420 and the substrate 412. [0054] In this example, the light source/light sensor 404 is configured to transmit a signal such as a laser or other light signal 432 toward the gap between the substrate 412 and the showerhead 420. For example, the light source/light sensor 404 is configured to transmit the light signal 432 responsive to control signals generated by a controller 436. In contrast to the example shown in FIG. 2, the light source/light sensor 404 receives a portion of the light signal 432 that is reflected by the showerhead 420 and the substrate 412 and provides a signal to the controller 436 indicative of characteristics of the light signal 432 as reflected. For example, the signal provided to the controller 436 may be indicative of a beam intensity of the portion of the light signal 432 that is reflected and received by the light source/light sensor 404. The controller 436 is configured to calculate a thickness of the substrate 412 and/or a width of the effective gap based on the measured characteristics of the light signal 432.

[0055] For example only, the beam intensity of the light signal 232 depends upon an amount of the light signal 432 that is reflected and does not pass through the effective gap. In other words, if the substrate 412 is thicker or the effective gap is otherwise reduced (e.g., due to manufacturing tolerances of the showerhead 420, substrate support 416, etc., contraction and expansion of components over time, component wear, etc.), less of the light signal 432 will be able to pass through the gap and more of the light signal 432 will be reflected toward the light source/light sensor 404. Conversely, if the substrate 412 is thinner or the effective gap is otherwise increased, more of the light signal 432 will be able to pass through the gap and less of the light signal 432 will be reflected toward the light source/light sensor 404.

[0056] Accordingly, in this example, a laser intensity I has an inversely proportional relationship with the gap TG and a proportional relationship with a substrate thickness Ts. The controller 436 is configured to calculate the effective gap and/or the substrate thickness based on the measured laser intensity as described in FIG. 2.

[0057] Although described with respect to substrate thickness and effective gap, the light source 204 and light sensor 208 and/or the light source/light sensor 404 may also be used to determine and adjust other characteristics of a processing chamber. For example, the characteristics of the light signal 232/432 may also be indicative of dimensions of other mechanical components including, but not limited to, a showerhead, upper electrode, or other component arranged above the substrate support, an upper plate of the substrate support, and edge ring, etc. [0058] Referring now to FIG. 4, a graph illustrating examples of gaps as a function of a sensed voltage when a substrate is present and when no substrate is present. The sensed voltage varies linearly with the gap. As a result, the sensed voltage can be used to measure the gap (which varies due to substrate thickness or other component variations). The gap is adjusted by varying the height of the substrate support and/or the showerhead (or other gas delivery device) to compensate for variations in the thickness of the substrate.

[0059] FIG. 5A to 5C show examples of gap compensation. In FIG. 5A, the substrate is thicker than expected and passive compensation is performed. The height of the substrate support or the showerhead is adjusted prior to processing to a predetermined gap. In FIG. 5B, the height of the substate is adjusted prior to processing (passive) and during processing (active). In FIG. 5C, the substrate is thinner than expected and passive and active gap compensation is performed. The height of the substrate support or the showerhead is adjusted prior to processing to the predetermined gap.

[0060] Referring now to FIG. 6, a method 500 for calibrating automatic gap compensation is shown. At 520, the method determines a linear equation for the processing chamber moving the substrate support to various heights and measuring the gap and/or by placing substrates or other materials having known thicknesses onto the substrate support and measuring the gap. In some examples, the calibration is performed at production temperature with no substrate or gas flow. At 524, the linear equation is used to perform active and/or passive compensation as will be described further below. At 528, the method determines whether recalibration is needed. Recalibration can be performed when preventive maintenance (PM) is performed, on an event basis, after a predetermined number of RF hours, and/or on a periodic basis such as daily, weekly or another period. If 528 is true, recalibration is performed at 532.

[0061] In some examples, the process chamber is idled for a predetermined period (e.g. 15 minutes or another period) at a pump down or vacuum condition. The actuator is initialized. The sensed voltage is measured at the end of the predetermined period and saved. The actuator moves to a predetermined number of positions and the sensed voltage is measured. For example only, five or ten sample points may be used and the actuator move a fixed or variable distance between each sample point, although additional or fewer sample points may be used. The sensed voltage is measured at predetermine intervals during a predetermined measuring period. In some examples, the measured voltage values are sensed multiple times and averaged at each gap setpoint. The measured values are saved and plotted to determine the linear equation (slope and intersect values). As can be appreciated, the measurement values can be converted to gap values and the gap values can be averaged or the measurement values can be averaged and the average of the measurement values can be converted to a gap value.

[0062] Referring now to FIG. 7, a gap compensation method 550 for performing passive gap compensation is shown. At 560, a substrate is arranged on the substrate support in the processing chamber for processing. At 564, prior to performing the process on the substrate, the gap is measured between the substrate and the showerhead at 564. At 568, the method determines whether a gap adjustment is needed. In some examples, the gap is adjusted by varying the height of the substrate support and/or the showerhead when the gap is outside of a predetermined range at 570. If the gap is in the predetermined range, no adjustment is performed. The method continues from 568 and 570 at 574. At 574, the process is performed. After processing, the substrate is removed from the processing chamber and the gap compensation method 550 is repeated for the next substrate if applicable.

[0063] Referring now to FIG. 8, a gap compensation method 600 for performing active gap compensation is shown. As can be appreciated, active gap compensation can be performed with or without performing passive gap compensation. In the example shown in FIG. 8, the method for performing active gap compensation begins with passive gap compensation as described above.

[0064] After performing passive gap compensation and initiating the process at 574, the method starts a timer that determines a predetermined compensation interval at 614. At 620, the method determines whether the process is complete. If 620 is false, the method continues at 624 and determines whether the timer is up. If 624 is false, the method returns to 620.

[0065] If 624 is true, the method measures the gap value at 628. As described above, a plurality of samples may be taken at a sampling interval during a gap measurement period. A mathematical function may be used to determine the gap value from the samples. In some examples, the sample values may be averaged during the gap measurement period, although other mathematical functions may be used. In other examples, a maximum or minimum value of the same values may be used as the gap value for the gap measurement period. In still other examples, a mid-average function or a moving average function may be used where minimum and maximum values are removed from the sample values and the remaining sample values are averaged.

[0066] At 632, the method determines whether a gap adjustment is required. The gap value is compared to a desired gap value or gap range and a difference is generated. In some examples, the difference between the measured gap value and the desired gap value and the difference is multiplied by a gain value that is greater than 0 and less than 1 to reduce noise and increase stability.

[0067] If 632 is true and adjustment of the gap is needed, the gap is adjusted based on the difference or the difference multiplied by a gain value at 634. If 632 is false, the method returns to 620. If 620 is true, the method ends.

[0068] As can be appreciated by the foregoing description, the systems and methods according to the present disclosure automatically compensate for variations in a gap between a substrate and a component of the substrate processing system. Compensation can be performed passively or actively to reduce substrate nonuniformities caused by variations in the gap due to substrate thickness variations or other factors. The systems and methods for gap compensation can be used during processing using RF plasma. A mathematical function such as averaging or other function can be used to reduce noise. Gain can be used to reduce overshoot.

[0069] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.

[0070] Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements or an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. 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.”

[0071] In some implementations, a controller is part of a system, which may be part of the above-described examples. Such systems can comprise semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform or platforms for processing, and/or specific processing components (a wafer substrate support, a gas flow system, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after processing of a semiconductor wafer or substrate. The electronics may be referred to as the “controller,” which may control various components or subparts of the system or systems. The controller, depending on the processing requirements and/or the type of system, may be programmed to control any of the processes disclosed herein, including the delivery of processing gases, temperature settings (e.g., heating and/or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and/or load locks connected to or interfaced with a specific system.

[0072] Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, memory, and/or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and/or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operational parameters may, in some embodiments, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and/or dies of a wafer.

[0073] The controller, in some implementations, may be a part of or coupled to a computer that is integrated with the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g. a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and/or settings, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control. Thus as described above, the controller may be distributed, such as by comprising one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.

[0074] Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing systems that may be associated or used in the fabrication and/or manufacturing of semiconductor wafers.

[0075] As noted above, depending on the process step or steps to be performed by the tool, the controller might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and/or load ports in a semiconductor manufacturing factory.