Multi-zone pedestal temperature control

Abstract

A system for processing a semiconductor substrate includes a substrate support assembly configured to support the semiconductor substrate. The substrate support assembly includes M resistive heaters disposed in M ​​zones (M is an integer greater than 1) within a layer in the substrate support assembly. The layer is adjacent to the semiconductor substrate. The substrate support assembly includes N temperature sensors disposed at N locations (N is an integer greater than 1 and equal to or less than M) within the layer. The system further includes a controller configured to control one or more of the M resistive heaters based on a temperature sensed by one of the N temperature sensors and an average temperature of one or more of the M zones.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 865,621, filed June 24, 2019, the entire disclosure of which is incorporated herein by reference.

[0002] TECHNICAL FIELD The present disclosure relates generally to substrate processing systems, and more particularly to temperature control of a multi-zone pedestal. [Background technology]

[0003] The background art provided herein is intended to provide a general background to the present disclosure. The inventors' work within the scope of this background art, and aspects of the description that may not otherwise be admitted as prior art at the time of filing, are not admitted, explicitly or implicitly, as prior art to the present disclosure.

[0004] Substrate processing systems may be used to etch, deposit, and / or perform other processes on substrates, such as semiconductor wafers. Examples of processes that may be performed on the substrate include, but are not limited to, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), atomic layer etch (ALE), plasma-enhanced atomic layer deposition (PEALD), and / or other etching, deposition, and cleaning processes. When processing a substrate, the substrate is placed on a substrate support, such as a pedestal or electrostatic chuck (ESC), within a processing chamber of the substrate processing system. To process the substrate, a process gas mixture is introduced into the processing chamber. In some examples, a plasma may be generated to promote chemical reactions within the processing chamber.

[0005] During substrate processing, the temperature of the substrate may be controlled by a resistive heater disposed on the substrate support pedestal. In some examples, the resistive heater is disposed in two or more separately controlled zones. Maintaining thermal uniformity in the zones heated by these resistive heaters typically requires either direct temperature measurement in each zone or indirect temperature measurement that is individually calibrated (e.g., using a known dependence of heater resistance on temperature). Summary of the Invention

[0006] A system for processing a semiconductor substrate includes a substrate support assembly configured to support a semiconductor substrate. The substrate support assembly includes M resistive heaters disposed in M zones (M is an integer greater than 1) within a layer of the substrate support assembly, the layer adjacent to the semiconductor substrate. The substrate support assembly includes N temperature sensors disposed at N locations (N is an integer greater than 1 and equal to or less than M) within the layer. The system further includes a controller configured to control one or more of the M resistive heaters based on a temperature sensed by one of the N temperature sensors and an average temperature of one or more of the M zones.

[0007] In other features, the M zones include a first circular zone located in a central region of the layer, a second annular zone surrounding the first circular zone, a first group of zones located in the first annular region surrounding the second annular zone, and a second group of zones located in the second annular region surrounding the first annular region.

[0008] In another feature, the first group of zones are rotated at an angle relative to the second group of zones.

[0009] In another feature, the first group of zones are rotated at a 45 degree angle relative to the second group of zones.

[0010] In another feature, the first annular region and the second annular region have different widths.

[0011] In another feature, the second annular zone has a different width than each of the first annular region and the second annular region.

[0012] In another feature, the first group of zones and the second group of zones each include four zones.

[0013] In other features, the N temperature sensors include a first temperature sensor located in the first circular zone, a first pair of temperature sensors located along a first diameter of the layer at a first boundary between the second annular zone and the first group of zones, and a second pair of temperature sensors located along a second diameter of the layer at a second boundary between the first group of zones and the second group of zones, the first temperature sensor being located at an intersection of the first diameter and the second diameter.

[0014] In other features, the locations of the first pair of temperature sensors and the second pair of temperature sensors correspond to vertices of a parallelogram, and the first diameter and the second diameter form a diagonal of the parallelogram.

[0015] In another feature, the controller is configured to control one of the M resistive heaters independently of other of the M resistive heaters.

[0016] In another feature, the controller is configured to control one or more of the M resistive heaters based on a target temperature profile for the semiconductor substrate.

[0017] In still other features, a substrate support assembly for supporting a semiconductor substrate includes a base plate including a layer adjacent to the semiconductor substrate. The substrate support assembly includes M resistive heaters disposed in M zones within the layer (M is an integer greater than 1). The M zones include a first circular zone located in a central region of the layer, a second annular zone surrounding the first circular zone, a first group of zones located in the first annular region surrounding the second annular zone, and a second group of zones located in the second annular region surrounding the first annular region. The substrate support assembly includes N temperature sensors disposed at N positions within the layer (N is an integer greater than 1 and equal to or less than M). The N temperature sensors include a first pair of temperature sensors located along a first diameter of the layer at a first boundary between the second annular zone and the first group of zones, a second pair of temperature sensors located along a second diameter of the layer at a second boundary between the first group of zones and the second group of zones, and a first temperature sensor located at an intersection of the first diameter and the second diameter within the first circular zone.

[0018] In other features, the locations of the first pair of temperature sensors and the second pair of temperature sensors correspond to vertices of a parallelogram, and the first diameter and the second diameter form a diagonal of the parallelogram.

[0019] In another feature, the first group of zones are rotated at an angle relative to the second group of zones.

[0020] In another feature, the first group of zones are rotated at a 45 degree angle relative to the second group of zones.

[0021] In another feature, the first annular region and the second annular region have different widths.

[0022] In another feature, the second annular zone has a different width than each of the first annular region and the second annular region.

[0023] In another feature, the first group of zones and the second group of zones each include four zones.

[0024] In other features, a system includes the substrate support assembly and a controller configured to control one or more of the M resistive heaters based on a temperature sensed by one of the N temperature sensors and an average temperature of one or more of the M zones.

[0025] In another feature, the controller is configured to control one of the M resistive heaters independently of other of the M resistive heaters.

[0026] In another feature, the controller is configured to control one or more of the M resistive heaters based on a target temperature profile for the semiconductor substrate.

[0027] In other features, a system includes the substrate support assembly and a controller configured to control one or more of the M resistive heaters using a temperature sensed by one of the N temperature sensors in combination with open-loop control of the M zones, wherein the open-loop control of the M zones includes correlating power supplied to each of the M zones with a measured temperature of the semiconductor substrate.

[0028] In other features, a system includes the substrate support assembly and a controller configured to control a first resistive heater of the M resistive heaters relative to a second resistive heater of the M resistive heaters based on a temperature sensed by one of the N temperature sensors and a resistance ratio between the first resistive heater and the second resistive heater.

[0029] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims, and drawings. It is to be understood that the detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. [Brief explanation of the drawings]

[0030] The present disclosure will become more fully understood from the following detailed description and the accompanying drawings.

[0031] [Figure 1A] FIG. 1A is a functional block diagram of an exemplary substrate processing system.

[0032] [Figure 1B] FIG. 1B is a diagram illustrating heater zones of a substrate support pedestal according to the present disclosure.

[0033] [Figure 2] FIG. 2 is a diagram showing temperature sensors arranged in the heater zone shown in FIG. 1B.

[0034] [Figure 3A] FIG. 3A is a functional block diagram of an exemplary heating system according to the present disclosure. [Figure 3B] FIG. 3B is a functional block diagram of an exemplary heating system according to the present disclosure.

[0035] [Figure 4] FIG. 4 is a flow chart of a method for arranging heater zones and temperature sensors according to the present disclosure.

[0036] [Figure 5] FIG. 5 is a flow chart of a first method for controlling heater zones according to the present disclosure.

[0037] [Figure 6] FIG. 6 is a flow chart of a second method for controlling heater zones according to the present disclosure.

[0038] In the drawings, the same reference numbers may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION OF THE INVENTION

[0039] Although this disclosure includes specific examples relating to temperature control of multiple zones in a substrate support pedestal of a substrate processing system, the systems and methods described herein are also applicable to temperature control of other types of components using zoned resistive heating.

[0040] In film deposition processes such as atomic layer deposition (ALD), the properties of the deposited film vary across a spatial (i.e., x-y coordinates in the horizontal plane) distribution. For example, substrate processing tools may have their own specifications for film thickness non-uniformity (NU). NU may be measured as the full range, half range, and / or standard deviation of a set of measurements made at predetermined locations on the semiconductor substrate surface. In some examples, NU may be reduced by addressing the direct cause of NU and / or by introducing compensatory NU to compensate for and offset existing NU. In other examples, material may be intentionally deposited and / or removed non-uniformly to compensate for known non-uniformities in other (e.g., previous or subsequent) steps in the process. In these other examples, a predetermined non-uniform deposition / removal profile may be calculated and used.

[0041] The substrate temperature during deposition can affect various properties of the deposited ALD film. Systems and methods according to the present disclosure are configured to adjust the temperature distribution across the substrate to reduce the thickness NU. For example, the temperature distribution may be adjusted to compensate for the known NU of a particular substrate processing tool (referred to as profile compensation) or to generate a predetermined NU profile for use in a particular process (referred to as profile adjustment).

[0042] For example, in an ALD process (e.g., oxide film deposition), a substrate is placed on a substrate support pedestal, such as an ALD pedestal. An ALD pedestal typically consists of a single zone. The ALD pedestal according to the present disclosure includes a multi-zone heater layer (e.g., 2 to 10 or more zones). The heater layer may be embedded in an upper layer of the pedestal. For example, the heater layer may include a heater layer made of polyimide and silicone at least partially encapsulated in an aluminum upper layer (e.g., an upper layer configured to support / contact a substrate placed on the substrate support pedestal). In this example, the aluminum upper layer arrangement may function as a Faraday cage. In another example, the upper layer may be a ceramic layer (e.g., Al2O3, AlN, etc.). Each zone of the heater layer controls the temperature of a respective zone of the pedestal. The upper layer is disposed on a base (e.g., a base plate) of the pedestal, and heat may be transferred from the upper layer to a coolable base plate.

[0043] The arrangement of the zones (e.g., quantity, shape, geometry, etc.) is configured to compensate for the known film thickness N resulting from the ALD process. The zones may include, but are not limited to, two or more radial (i.e., annular) zones of different widths, two or more partitioned radial zones (i.e., a radial zone comprising multiple partitioned / azimuthal zones), an outer radial zone adjacent to and / or overlapping the edge of the substrate, and an outer radial zone positioned to adjust the temperature of the carrier ring (e.g., to control / modify the radial profile for deposition and / or trimming removal).

[0044] As an example, the zones include 10 zones: a central zone, an inner intermediate radial zone, four outer intermediate radial zones (i.e., an outer intermediate radial zone consisting of four sections), and four outer peripheral zones (i.e., an outer peripheral zone consisting of four sections). In some examples, the radial zones may include five or more sections (e.g., eight or more sections). Furthermore, the azimuthal zones in adjacent radial zones may not be aligned. Instead, the azimuthal zones in one radial zone may have different rotational orientations (i.e., clocking) relative to adjacent radial zones.

[0045] Each zone is provided with a resistive heater. The resistive heater includes a resistive element made of a material with a high temperature coefficient of resistance (TCR). Accordingly, throughout this disclosure, the resistive heater is also referred to as a high-TCR heater or high-TCR heater element. In some examples, the heater element has a high TCR of greater than 0.001 per degree Celsius. By way of example only, heater elements made of molybdenum, tungsten (W), copper, or nickel may be used. In other examples, the heater element has a lower TCR of less than 0.001 per degree Celsius. By way of example only, a stainless steel (SST) alloy may be used.

[0046] The heater zone temperatures are controlled (i.e., by controlling the power delivered to the resistive heaters in multiple zones) to achieve a target temperature profile (also known as a heat map) for the substrate being processed. One method for controlling the temperature of multiple zones is open-loop control, which correlates the power delivered to each zone with the measured wafer temperature. However, this method, when used alone, has several disadvantages. For example, open-loop control lacks data about any load changes that may occur in the wafer's environment and cause changes in the substrate temperature. Open-loop control also has a slower response time when transitioning from one temperature setpoint to another than closed-loop control. That is, when changing the power delivered to one or more zones to produce a desired temperature change, the actual temperature change may occur much more slowly than when closed-loop control is used.

[0047] In contrast, closed-loop control (e.g., PID control) uses a feedback loop to control the power supplied to each zone. This has two advantages. First, closed-loop control allows for temperature control that is more robust to other stimuli (e.g., load changes) than open-loop control. Second, closed-loop control provides a faster response time than open-loop control when transitioning from one temperature setpoint to another. In other words, when changing the power supplied to one or more zones to produce a desired temperature change, the actual temperature change occurs more quickly than with open-loop control.

[0048] If multiple zones, each equipped with a thermocouple (TC), are arranged on the pedestal, a correlation between the wafer temperature and the TC may be sufficient to control the temperature distribution across the wafer. Alternatively, as described below, the minimum number of TCs that provide the local temperature of a selected zone and the average temperature of multiple zones can be used to control the temperature distribution across the wafer.

[0049] As described below, the present disclosure relates to a temperature control scheme that combines local temperature measurements on the pedestal surface (e.g., using a TC or resistance thermometer, also known as a resistance temperature detector (RTD)) with average temperature or open-loop control of multiple zones. Specifically, the proposed temperature control scheme combines local temperature measurements (e.g., using a TC, RTD, or similar method) in fewer than all zones with open-loop current / voltage control for zones not equipped with a TC. The TC provides the local temperature of a zone, which represents the temperature at a point within that zone. Furthermore, average temperature measurements of heater elements in multiple zones are used in combination with these local temperature measurements to accurately set the pedestal surface temperature to a predetermined temperature profile.

[0050] The high TCR-based method of measuring average zone temperature can be used with multiple (e.g., 10) zones to provide closed-loop control for all zones. The high TCR-based method measures the resistance of the high TCR heater element within a zone. This measurement is correlated with temperature using a lookup table or formula to obtain the average temperature within that zone. The high TCR-based method provides an average temperature across multiple zones. This average temperature can be used directly or combined with local temperature measurements. These and other aspects of the disclosure are described in more detail below.

[0051] 1A and 1B illustrate an example of a substrate processing system 100 including a substrate support pedestal (e.g., an ALD pedestal) 104 in accordance with the present disclosure. The substrate support pedestal 104 is disposed within a processing chamber 108. A substrate 112 is disposed on the substrate support pedestal 104 during processing. In some examples, the substrate support pedestal 104 may be configured to minimize contact with the substrate 112 (e.g., only the outer edge of the substrate 112 may contact the top surface of the substrate support pedestal 104, or the substrate 112 may be positioned on a minimum contact area (MCA) feature). In other examples, the substrate support pedestal 104 may be configured to allow gas clamping on its backside.

[0052] Gas delivery system 120 includes gas sources 122-1, 122-2, . . . 122-N (collectively referred to as gas sources 122) connected to valves 124-1, 124-2, . . . 124-N (collectively referred to as valves 124) and mass flow controllers 126-1, 126-2, . . . 126-N (collectively referred to as MFCs 126). MFCs 126 control the flow of gas from gas sources 122 to manifold 128, where the gases mix. The output of manifold 128 is fed through optional pressure regulator 132 to manifold 136. The output of manifold 136 is input to multi-injector showerhead 140. Note that while manifolds 128 and 136 are shown, a single manifold could also be used.

[0053] The substrate support pedestal 104 includes multiple zones. For example, as shown in FIG. 1B , the substrate support pedestal 104 includes a central zone 144, an inner intermediate radial zone 148, four outer intermediate radial zones (i.e., the outer intermediate radial zone 152 consisting of four sections 152-1, 152-2, 152-3, and 152-4), and four outer peripheral zones (i.e., the outer peripheral zone 156 consisting of four sections 156-1, 156-2, 156-3, and 156-4). The sections of the outer peripheral zone 156 are offset (i.e., rotated relative to the sections of the outer intermediate radial zone 152) (e.g., 45 degrees) from the sections of the outer intermediate radial zone 152. In some examples, the substrate support pedestal 104 may include a second outer peripheral zone 158 radially outward from the outer peripheral zone 156. For example, the inner diameter of the second outer peripheral zone 158 may be larger than the diameter of the substrate 112. The temperature of the substrate support pedestal 104 may be controlled using individually controllable resistive heaters 160 located in each of the zones, as described below.

[0054] In some examples, the outer edge zone 156 may overlap and / or extend beyond (i.e., radially beyond) the outer edge of the substrate 112. For example, for a 300 mm substrate, the radius of the outer edge zone 156 may be greater than 300 mm. Furthermore, the width of the outer edge zone 156 (i.e., the distance from the inner radius to the outer radius) may be smaller than the widths of the inner intermediate radial zone 148 and the outer intermediate radial zone 152. For example, the width of the outer edge zone 156 may be approximately 10 mm (e.g., ±2 mm), and the widths of the inner intermediate radial zone 148 and the outer intermediate radial zone 152 may each be approximately 40 mm (e.g., ±2 mm). The relatively narrow width of the outer edge zone 156 may facilitate fine adjustment at the outer edge of the substrate 112.

[0055] In some examples, the substrate support pedestal 104 may include coolant channels 164. Cooling fluid is supplied to the coolant channels 164 from a fluid reservoir 168 and a pump 170. Pressure sensors 172, 174 may be located on the manifold 128 or the manifold 136, respectively, to measure pressure. A valve 178 and a pump 180 may be used to evacuate reactants from the processing chamber 108 and / or to control the pressure within the processing chamber 108.

[0056] The controller 182 includes a dosage controller 184 that controls the dosage from the multi-injector showerhead 140. The controller 182 also controls the gas supply from the gas delivery system 120. The controller 182 controls the pressure in the process chamber and / or the evacuation of reactants using valves 178 and pumps 180. The controller 182 controls the temperature of the substrate support pedestal 104 and the substrate 112, as described below.

[0057] FIG. 2 illustrates the radial zones of the pedestal. The radial zones are labeled R1, R2,..., R10. Thermocouples TC1, TC2,..., TC5 (shown as solid circles) are positioned as shown. Note that while TCs are used for illustrative purposes throughout this disclosure, it is understood that RTDs can be used in place of or in combination with TCs. Specifically, TC1 is positioned at the center of central zone R1 (element 144). Thermocouples TC2, TC3, TC4, and TC5 are positioned at the boundaries between radial zones in a crossing pattern as shown.

[0058] Specifically, as shown, two thermocouples TC3 and TC5 are arranged in a cross pattern at diametrically opposed ends on the boundary between radial zone R2 (element 148) and radial zones R3, R4, R5, and R6 (element 152). As shown, the two thermocouples TC3 and TC5 may be located along a first diameter of the pedestal that passes through the centers of radial zones R4 and R6. Also as shown, this first diameter passes through the junction of radial zones R7 and R8 and the junction of radial zones R9 and R10. As shown, the two thermocouples TC3 and TC5 may be adjacent to or near the centers of radial zones R4 and R6, respectively.

[0059] Two other thermocouples, TC2 and TC4, are arranged in a cross pattern at diametrically opposite ends on the boundary between radial zones R3, R4, R5, and R6 (element 152) and radial zones R7, R8, R9, and R10 (element 156), as shown. As shown, these two other thermocouples, TC2 and TC4, may be located along a second diameter of the pedestal that passes through the centers of radial zones R3 and R5. Also as shown, this second diameter passes through the junction of radial zones R7 and R10 and the junction of radial zones R8 and R9. As shown, thermocouple TC2 may be located at the junction of radial zones R7 and R10, and thermocouple TC4 may be located at the junction of radial zones R8 and R9.

[0060] For example, the first and second diameters of the pedestal may intersect at 90 degrees or another angle. For example, thermocouples TC2, TC3, TC4, and TC5 may be located at the vertices of a parallelogram, with the first and second diameters forming diagonals of the parallelogram. Thermocouple TC1 may be located at the intersection of the first and second diameters, as shown.

[0061] When positioned in this manner, thermocouples TC1, TC2, TC5 can record the thermal interactions between zones and the local temperatures at two different diameters of the pedestal. A heat map of all zones can be constructed using the average temperature of each zone obtained from the high TCR heater elements and the local temperatures of selected zones obtained from the TC of these selected zones. Furthermore, a target temperature distribution across the wafer can be achieved by controlling the heater elements using a combination of the local temperatures of selected zones and the average temperature of each zone.

[0062] Calibration of high TCR heaters (i.e., determining the correspondence between temperature and measurements) can be performed using local temperature measurements. For example, in an open-loop calibration method, the power input to zones R1-R10 is sequentially increased by X% (i.e., R1, then R2, then R3, etc.) and the wafer temperature is measured. A sensitivity measurement of the wafer temperature to the power value of each zone is defined (e.g., dT / dp, where T is the wafer temperature and p is the power expressed as voltage, current, or both). While the wafer temperature data is being collected, the average temperature of each zone is also measured in parallel, and the sensitivity measurement of the wafer temperature to the average temperature of each zone, dT / dT, is calculated. heater-element Also, define another sensitivity measure of the average zone temperature to the power value of each zone, dT heater-element / dp can also be defined. Therefore, the power supplied to each zone or the average temperature of the zone can be set as the control variable. By controlling either or both of these, the wafer temperature can be controlled.

[0063] Whether the average zone temperature is used as an additional (i.e., supplementary) control variable (to improve the target accuracy of the wafer temperature distribution profile) or as the primary control variable may be time-dependent. At steady state, open-loop control can be used to control the wafer temperature. When switching states (e.g., due to load changes), the average zone temperature may be used as the primary control variable. The average temperature of a zone is obtained by analyzing the resistance-temperature relationship data from the high TCR heater elements in that zone. For example, the average temperature may be an area-weighted average depending on the area of the high TCR heater elements.

[0064] In some situations, the overhead of calculating the average zone temperature can be avoided. For example, if the average zone temperature is used as an auxiliary variable (e.g., for transient response), then instead of using the average temperature of two zones, the resistance ratio of the heater elements in two zones can be used to increase or decrease the power supplied to the heater element in one of those two zones, as described below.

[0065] There are several methods available for controlling wafer temperature. For example, the simplest method is to control the power supplied to each zone based on the average temperature of that zone. The most complex method is to define a least mean squares (LMS) temperature target for the entire heat map and then control the power supplied to each zone using pulse width modulation (PWM).

[0066] A hybrid approach of medium complexity uses a minimum number of TCs in combination with the average zone temperature to control a particular zone.Fourth, open-loop control can be used to control the zone temperature at steady state, and the average zone temperature can be used as the primary control variable when switching states (e.g., during load changes).

[0067] Some examples of hybrid methods are shown below. As an example, in Figure 2, TC1, TC2, and TC3 can control the input to the baseline for zones R1, R2, and all outer zones, respectively. The average zone temperature is used as the input to control the resistance ratio between zones. The resistance ratio between zones is controlled by open-loop control.

[0068] For example, consider the outer zones R7, R8, R9, and R10. These zones have the same area. Assume the heater element measurements in these zones are equal. If these zones are to have the same target temperature, one of the zones, say zone R8, is driven to the target temperature using the local temperature of zone R8. Zones R7, R9, and R10 are driven to the same resistance value that corresponds to this target temperature. Assuming these zones originally had the same resistance value at cold or steady state, if the measurements of these hot zones are the same after heating, then the zones will have the same temperature (i.e., the target temperature).

[0069] Next, suppose zone R10 is to be hotter than zone R8. If the temperature ratio to be achieved between zones R8 and R10 is known, zone R10 can be driven to a lower resistance than zone R8, such that the resistance ratio between zones R8 and R10 corresponds to the temperature ratio between zones R8 and R10. Thus, when switching states (e.g., during a load change), in addition to controlling specific zones with a minimum number of TCs (local temperature measurements), the average zone temperature can be used to control the resistance ratio between the azimuthal zones. In another example of a hybrid approach, zone R6 can be controlled by TC5, while zone R2 is controlled by the average zone temperature.

[0070] FIG. 3A illustrates a controller 300 that can be used to control heater zones R1-R10 shown in FIG. 2. For example, controller 300 may be implemented by controller 182 shown in FIG. 1A. A heater driver 302 may be used to provide power to a selected TCR heater 304 under the control of controller 300. For example, TCR heater 304 may be used to implement resistive heater 160 (shown in FIG. 1A). A current sensor 308 may be used to sense the current provided to TCR heater 304 by heater driver 302. A voltage sensor 310 may be used to sense the voltage provided to TCR heater 304 by heater driver 302. Controller 300 determines a measurement value for each TCR heater 304 based on current and / or voltage measurements obtained from current sensor 308 and / or voltage sensor 310, respectively.

[0071] 3B illustrates how controller 300 monitors the duty cycle of a heater zone and estimates the heater zone measurement value based on the corresponding duty cycle using resistance estimator 312. This example assumes that the voltage or current is a constant value and the duty cycle of the current or voltage varies. That is, controller 300 estimates the measurement value based on the known voltage or current and the duty cycle of that current or voltage. Therefore, current sensor 308 and voltage sensor 310 are omitted in this example.

[0072] 3A and 3B, a controller 300 controls TCR heaters 304 in heater zones R1-R10. The controller 300 selects a heater zone (e.g., one of zones R1, R2, etc. shown in FIG. 2). A heater driver 302 supplies power to the selected TCR heater 304. The operation of the controller 300 and other components shown in FIGS. 3A and 3B will be described in more detail below with reference to FIGS. 5 and 6.

[0073] 4 illustrates a method 400 for disposing multiple zones (and their respective heaters) and temperature sensors (e.g., TCs and / or RTDs) in accordance with the present disclosure. Method 400 includes, at step 402, disposing high TCR heater elements in multiple zones in an upper layer of a pedestal, where the upper layer of the pedestal is configured to support a substrate during substrate processing. Method 400 includes, at step 404, disposing the multiple zones as follows: That is, the zones include a first zone located in a central region of the upper layer of the pedestal (e.g., zone R1 (144) shown in FIGS. 1B and 2), a second zone located in an inner annular region surrounding the central region (e.g., zone R2 (148) shown in FIGS. 1B and 2), a first group of zones located in an outer annular region surrounding the inner annular zone (e.g., zones R3, R4, R5, R6, or zone 152 shown in FIGS. 1B and 2), and a second group of zones located in an outer peripheral region surrounding the outer annular region (e.g., zones R7, R8, R9, R10, or zone 156). The second group of zones may be offset by an angle (e.g., 45 degrees) from the first group of zones (e.g., as shown in FIG. 1B).

[0074] At step 406, the method 400 includes arranging a number of temperature sensors (e.g., TCs and / or RTDs) less than the number of zones, as follows: Arranging one TC in a first zone (e.g., TC1 in zone R1 (144) shown in FIG. 2 ); Arranging a first pair of TCs (TC3 and TC5 shown in FIG. 2 ) along a first boundary and along a first diameter between the inner annular region (zone R2 (148)) and the outer annular region (zone 152); and Arranging a second pair of TCs (TC2 and TC4 shown in FIG. 2 ) along a second boundary and along a second diameter between the outer annular region (zone 152) and the peripheral region (zone 156).

[0075] The method 400 includes, at step 408, placing first and second pairs of temperature sensors along the vertices of a parallelogram formed by the first and second diameters, with TC1 being located at the intersection of the first and second diameters (i.e., the intersection of the diagonals).

[0076] FIG. 5 illustrates a first method 500 for controlling zones (e.g., R1-R10 shown in FIGS. 1B and 2) according to the present disclosure. Method 500 is performed by controller 300 and other components shown in FIGS. 3A and 3B. Method 500 begins at step 502 by measuring the local temperatures of selected zones (fewer than all zones) using temperature sensors positioned as shown in FIG. 2 and described with reference to FIG. 4. At step 504, the average temperature of each zone is measured.

[0077] At step 506, it is determined whether the zone is at steady state. If the zone is at steady state, then at step 508, the zone is controlled by open loop control (i.e., by correlating the power supplied to each zone with the measured temperature of the wafer).

[0078] Method 500 determines whether a change in the state of one or more zones is required (e.g., due to a change in load) at step 510. If a change in the state of one or more zones is not required (i.e., the zones are in a steady state), method 500 returns to step 508. If a change in the state of one or more zones is required, method 500 controls the power supplied to those one or more zones at step 512 using a combination of the local temperature measured in at least one (but not all) zone and the average temperature of all zones.

[0079] 6 illustrates a second method 600 for controlling zones (e.g., R1-R10 shown in FIGS. 1B and 2) according to the present disclosure. Method 600 is performed by controller 300 and other components shown in FIGS. 3A and 3B. Method 600 begins at step 602 by measuring the local temperatures of selected zones (fewer than all of the zones) using temperature sensors positioned as shown in FIG. 2 and described with reference to FIG. 4.

[0080] The method 600 determines whether the zone is in a steady state at step 604. If the zone is in a steady state, the method 600 controls the zone with open loop control (i.e., by correlating the power supplied to each zone with the measured temperature of the wafer) at step 606.

[0081] Method 600 determines whether a change in state of one or more zones is required (e.g., due to a change in load) at step 608. If a change in state of one or more zones is not required (i.e., the zones are at steady state), method 600 returns to step 606. If a change in state of one or more zones is required, method 600 determines a resistance ratio between two zones, one of which requires a state change, at step 610 based on a desired temperature change for the zone(s) requiring a state change.

[0082] Method 600 controls the power supplied to the zone needing a state change using a combination of the local temperature measured in at least one (but not all) zone and the resistance ratio between the two zones at step 612. Thus, the power to the zone needing a state change is increased or decreased based on a combination of the local temperature measured in at least one (but not all) zone and the resistance ratio between the two zones.

[0083] The foregoing description is merely exemplary in nature and is not intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be embodied in a variety of forms. Thus, while the disclosure includes specific examples, the true scope of the disclosure should not be limited thereto, as other modifications will become apparent from a closer examination of the drawings, the specification, and the following claims.

[0084] It should be understood that one or more steps in a method may be performed in a different order (or in parallel) without altering the principles of the present disclosure. Furthermore, although each embodiment is described above as having specific features, any one or more of these features described in connection with any embodiment of the present disclosure may be included with any feature of any other embodiment and / or may be implemented in combination (even if not explicitly stated). That is, the above-described embodiments are not mutually exclusive, and one or more embodiments may be substituted for one another within the scope of the present disclosure.

[0085] Spatial and functional relationships between elements (e.g., 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 expressly stated as "directly," when a relationship between a first element and a second element is described in the above disclosure, the relationship can be a direct relationship where no other intervening elements exist between the first element and the second element, or an indirect relationship where one or more intervening elements (spatial or functional) exist between the first element and the second element.

[0086] 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 not to mean "at least one of A, at least one of B, and at least one of C."

[0087] In some implementations, the controller is part of a system, which may be part of the examples described above. Such systems may include semiconductor processing equipment, including one or more processing tools, one or more chambers, one or more processing platforms, and / or specific processing components (such as a wafer pedestal or gas flow system). These systems may be integrated with electronics for controlling the operation of the systems before, during, and after processing of semiconductor wafers or substrates. The electronics may also be referred to as a "controller" and may control various components or subparts of one or more systems.

[0088] The controller may be programmed to control any of the processes disclosed herein depending on the processing requirements and / or type of system, including process gas supply, 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 supply settings, position and motion settings, wafer loading and unloading to and from the tool, and wafer loading and unloading to and from other transfer tools and / or load locks connected or associated with the particular system.

[0089] Broadly, a controller may be defined as an electronic device having various integrated circuits, logic, memory, and / or software to receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. Integrated circuits may include chips as 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).

[0090] The program instructions may be instructions communicated to the controller as various individual settings (or program files) that define operational parameters for performing a particular process on or for a semiconductor wafer or for a system. In some embodiments, the operational parameters may be part of a recipe defined by a process engineer to accomplish one or more processing steps in the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or wafer dies.

[0091] In some implementations, the controller may be part of or coupled to a computer, where the computer may be integrated into the system, coupled to the system, or otherwise networked with the system, or a combination thereof. For example, the controller may reside in the "cloud" or in all or part of a factory host computer system, enabling remote access of wafer processing. The computer may enable remote access to the system to monitor the progress of a manufacturing process, examine past manufacturing process history, or examine trends or performance indicators from multiple manufacturing processes, and may change parameters of a current process, set up processing steps following the current process, or initiate a new process.

[0092] In some examples, a process recipe can be provided to the system from a remote computer (e.g., a server) over a network, where the network may include a local network or the Internet. The remote computer may include a user interface that allows for input or programming of parameters and / or settings. These parameters and / or settings are then communicated from the remote computer to the system.

[0093] In some examples, the controller receives instructions as data that specifies parameters for each process step to be performed in one or more operations, although it should be understood that these parameters may be specific to the type of process being performed and the type of tool the controller is configured to interface with or control.

[0094] Thus, as described above, the controller may be distributed, such as by having one or more individual controllers that are networked and work toward a common goal, such as the processes and controls described herein. An example of a distributed controller for such a purpose is one or more integrated circuits mounted in the chamber that communicate with one or more integrated circuits located remotely (e.g., at the platform level or as part of a remote computer), which cooperate to control the process in the chamber.

[0095] Non-limiting examples of systems 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 cleaning 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 system related to or usable in the manufacturing and / or production of semiconductor wafers.

[0096] As described above, depending on one or more process steps being performed by the tool, the controller may communicate with one or more of other tool circuits or tool modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools located throughout the factory, a main computer, another controller, or tools used in material transport to and from tool locations and / or load ports within a semiconductor manufacturing factory. The present disclosure can also be realized in the following forms. [Form 1] 1. A system for processing semiconductor substrates, comprising: a substrate support assembly configured to support the semiconductor substrate, M resistive heaters disposed in M zones (M is an integer greater than 1) in a layer of the substrate support assembly adjacent to the semiconductor substrate; a substrate support assembly including: N temperature sensors positioned at N locations within the layer, where N is an integer greater than 1 and less than or equal to M; a controller configured to control one or more of the M resistive heaters based on a temperature sensed by one of the N temperature sensors and an average temperature of one or more of the M zones; Including, the system. [Form 2] 10. The system according to claim 1, The M zones are: a first circular zone located in a central region of the layer; a second annular zone surrounding the first circular zone; a first group of zones located in a first annular region surrounding the second annular zone; a second group of zones located in a second annular region surrounding the first annular region; system. [Form 3] The system according to aspect 2, the first group of zones are rotated at an angle relative to the second group of zones; system. [Form 4] The system according to aspect 2, the first group of zones are rotated at a 45 degree angle relative to the second group of zones; system. [Form 5] The system according to aspect 2, the first annular region and the second annular region have different widths; system. [Form 6] The system according to aspect 2, the second annular zone has a width different from each of the first annular region and the second annular region; system. [Form 7] The system according to aspect 2, the first group of zones and the second group of zones each include four zones; system. [Form 8] The system according to aspect 2, The N temperature sensors a first temperature sensor located in the first circular zone; a first pair of temperature sensors located along a first diameter of the layer at a first boundary between the second annular zone and the first group of zones; a second pair of temperature sensors located along a second diameter of the layer at a second boundary between the first group of zones and the second group of zones; the first temperature sensor is located at an intersection of the first diameter and the second diameter; system. [Form 9] The system according to aspect 8, the positions of the first pair of temperature sensors and the second pair of temperature sensors correspond to vertices of a parallelogram; the first diameter and the second diameter form a diagonal of the parallelogram. system. [Form 10] 10. The system according to claim 1, the controller is configured to control one of the M resistive heaters independently of other of the M resistive heaters; system. [Form 11] 10. The system according to claim 1, the controller is configured to control one or more of the M resistive heaters based on a target temperature profile of the semiconductor substrate. system. [Form 12] A substrate support assembly for supporting a semiconductor substrate, comprising: a base plate including a layer adjacent to the semiconductor substrate; M resistive heaters disposed in M zones within the layer, where M is an integer greater than 1, respectively, wherein the M zones are: a first circular zone located in a central region of the layer; a second annular zone surrounding the first circular zone; a first group of zones located in a first annular region surrounding the second annular zone; a second group of zones located in a second annular region surrounding the first annular region; and N temperature sensors arranged at N locations within the layer (N is an integer greater than 1 and less than or equal to M), a first pair of temperature sensors located along a first diameter of the layer at a first boundary between the second annular zone and the first group of zones; a second pair of temperature sensors located along a second diameter of the layer at a second boundary between the first group of zones and the second group of zones; N temperature sensors, including a first temperature sensor located within the first circular zone at an intersection of the first diameter and the second diameter; a substrate support assembly including: [Form 13] 13. A substrate support assembly according to claim 12, comprising: the positions of the first pair of temperature sensors and the second pair of temperature sensors correspond to vertices of a parallelogram; the first diameter and the second diameter form a diagonal of the parallelogram. Substrate support assembly. [Form 14] 13. A substrate support assembly according to claim 12, comprising: the first group of zones are rotated at an angle relative to the second group of zones; Substrate support assembly. [Form 15] 13. A substrate support assembly according to claim 12, comprising: the first group of zones are rotated at a 45 degree angle relative to the second group of zones; Substrate support assembly. [Form 16] 13. A substrate support assembly according to claim 12, comprising: the first annular region and the second annular region have different widths; Substrate support assembly. [Form 17] 13. A substrate support assembly according to claim 12, comprising: the second annular zone has a width different from each of the first annular region and the second annular region; Substrate support assembly. [Form 18] 13. A substrate support assembly according to claim 12, comprising: the first group of zones and the second group of zones each include four zones; Substrate support assembly. [Form 19] 1. A system comprising: A substrate support assembly according to aspect 12; a controller configured to control one or more of the M resistive heaters based on a temperature sensed by one of the N temperature sensors and an average temperature of one or more of the M zones; Including, the system. [Form 20] 20. The system according to claim 19, the controller is configured to control one of the M resistive heaters independently of other of the M resistive heaters; system. [Form 21] 20. The system according to claim 19, the controller is configured to control one or more of the M resistive heaters based on a target temperature profile of the semiconductor substrate. system. [Form 22] 1. A system comprising: A substrate support assembly according to aspect 12; a controller configured to control one or more of the M resistive heaters using a temperature sensed by one of the N temperature sensors in combination with open-loop control of the M zones; open-loop control of the M zones includes correlating power supplied to each of the M zones with a measured temperature of the semiconductor substrate. system. [Form 23] 1. A system comprising: A substrate support assembly according to aspect 12; a controller configured to control a first resistive heater of the M resistive heaters relative to a second resistive heater of the M resistive heaters based on a temperature sensed by one of the N temperature sensors and a resistance ratio between the first resistive heater and the second resistive heater; Including, the system.

Claims

1. 1. A system for processing semiconductor substrates, comprising: a substrate support assembly configured to support the semiconductor substrate, M resistive heaters disposed in M zones (M is an integer greater than 1) in a layer of the substrate support assembly adjacent to the semiconductor substrate; a substrate support assembly including: N temperature sensors positioned at N locations within the layer, where N is an integer greater than 1 and less than or equal to M; a controller configured to control one or more of the M resistive heaters based on a temperature sensed by one of the N temperature sensors and an average temperature of one or more of the M zones; Including, The M zones are: a first circular zone located in a central region of the layer; a second annular zone surrounding the first circular zone; a first group of zones located in a first annular region surrounding the second annular zone; a second set of zones located in a second annular region surrounding the first annular region; the first group of zones includes a plurality of first zones located in the first annular region; the second group of zones includes a plurality of second zones located in the second annular region; the first zones are positioned at positions rotated relative to the second zones, The N temperature sensors are a first temperature sensor located in the first circular zone; a first pair of temperature sensors located along a first diameter of the layer at a first boundary between the second annular zone and the first group of zones; a second pair of temperature sensors located along a second diameter of the layer at a second boundary between the first group of zones and the second group of zones; the first temperature sensor is located at an intersection of the first diameter and the second diameter; system.

2. 10. The system of claim 1, the first group of zones are rotated at a 45 degree angle relative to the second group of zones; system.

3. 10. The system of claim 1, the first annular region and the second annular region have different widths; system.

4. 10. The system of claim 1, the second annular zone has a width different from each of the first annular region and the second annular region; system.

5. 10. The system of claim 1, the first group of zones includes four of the first zones; the second group of zones includes four of the second zones; system.

6. 10. The system of claim 1, the positions of the first pair of temperature sensors and the second pair of temperature sensors correspond to vertices of a parallelogram; the first diameter and the second diameter form a diagonal of the parallelogram. system.

7. 10. The system of claim 1, the controller is configured to control one of the M resistive heaters independently of other of the M resistive heaters; system.

8. 10. The system of claim 1, the controller is configured to control one or more of the M resistive heaters based on a target temperature profile of the semiconductor substrate. system.

9. A substrate support assembly for supporting a semiconductor substrate, comprising: a base plate including a layer adjacent to the semiconductor substrate; M resistive heaters disposed in M zones within the layer, where M is an integer greater than 1, respectively, wherein the M zones comprise: a first circular zone located in a central region of the layer; a second annular zone surrounding the first circular zone; a first group of zones located in a first annular region surrounding the second annular zone; a second group of zones located in a second annular region surrounding the first annular region; and N temperature sensors arranged at N locations within the layer (N is an integer greater than 1 and less than or equal to M), a first pair of temperature sensors located along a first diameter of the layer at a first boundary between the second annular zone and the first group of zones; a second pair of temperature sensors located along a second diameter of the layer at a second boundary between the first group of zones and the second group of zones; N temperature sensors, including a first temperature sensor located within the first circular zone at an intersection of the first diameter and the second diameter; a substrate support assembly including:

10. 10. The substrate support assembly of claim 9, the positions of the first pair of temperature sensors and the second pair of temperature sensors correspond to vertices of a parallelogram; the first diameter and the second diameter form a diagonal of the parallelogram. Substrate support assembly.

11. 10. The substrate support assembly of claim 9, the first group of zones are rotated at an angle relative to the second group of zones; Substrate support assembly.

12. 10. The substrate support assembly of claim 9, the first group of zones are rotated at a 45 degree angle relative to the second group of zones; Substrate support assembly.

13. 10. The substrate support assembly of claim 9, the first annular region and the second annular region have different widths; Substrate support assembly.

14. 10. The substrate support assembly of claim 9, the second annular zone has a width different from each of the first annular region and the second annular region; Substrate support assembly.

15. 10. The substrate support assembly of claim 9, the first group of zones and the second group of zones each include four zones; Substrate support assembly.

16. 1. A system comprising: A substrate support assembly according to claim 9; a controller configured to control one or more of the M resistive heaters based on a temperature sensed by one of the N temperature sensors and an average temperature of one or more of the M zones; Including, the system.

17. 17. The system of claim 16, the controller is configured to control one of the M resistive heaters independently of other of the M resistive heaters; system.

18. 17. The system of claim 16, the controller is configured to control one or more of the M resistive heaters based on a target temperature profile of the semiconductor substrate. system.

19. 1. A system comprising: A substrate support assembly according to claim 9; a controller configured to control one or more of the M resistive heaters using a temperature sensed by one of the N temperature sensors in combination with open-loop control of the M zones; open-loop control of the M zones includes correlating power supplied to each of the M zones with a measured temperature of the semiconductor substrate. system.

20. 1. A system comprising: A substrate support assembly according to claim 9; a controller configured to control a first resistive heater of the M resistive heaters relative to a second resistive heater of the M resistive heaters based on a temperature sensed by one of the N temperature sensors and a resistance ratio between the first resistive heater and the second resistive heater; Including, the system.

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