Dynamic temperature control of zoned substrate support in substrate processing system

Abstract

A method for controlling a substrate support temperature includes setting a temperature of the substrate support in one of Z zones in response to a temperature sensor embedded in the one of the Z zones; setting the temperature of the substrate support in Z-1 zones of the Z zones using Z-1 power ratios, respectively; measuring Z resistances of Z resistive heaters embedded in the Z zones at first and second temperatures; setting the temperature of the substrate support to a third temperature in response to the temperature sensor and the Z-1 power ratios; determining Z-1 first target resistances for the Z-1 zones, respectively, at the third temperature; measuring the Z resistances of the Z resistive heaters at the third temperature, respectively; and comparing Z-1 resistances of Z-1 resistive heaters for the Z-1 zones and the Z-1 first target resistances at the third temperature, respectively, and adjusting the Z-1 power ratios.

Description

DYNAMIC TEMPERATURE CONTROL OF ZONED SUBSTRATE SUPPORT IN SUBSTRATE PROCESSING SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 535,029, filed on August 28, 2023. The entire disclosure of the application referenced above is incorporated herein by reference.FIELD

[0002] The present disclosure relates to substrate processing systems, and more particularly to substrate processing systems including dynamic temperature control of a substrate support.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 perform etching, deposition, and / or other treatment of substrates such as semiconductor wafers. During processing, a substrate is arranged on a substrate support, such as a pedestal, an electrostatic chuck (ESC), etc. in a processing chamber of the substrate processing system. A process gas mixture is introduced into the processing chamber to treat the substrate. In some examples, plasma may be struck to enhance chemical reactions within the processing chamber.

[0005] During substrate processing, the temperature of the substrate may be controlled by varying power to resistance heaters that are arranged in the substrate support. In some examples, the resistance heaters are arranged into two or more zones of the substrate support that are controlled separately. Maintaining thermal uniformity in multiple zones that are heated by the resistance heaters usually requires either direct temperature measurement in each zone or individually calibrated indirect temperature measurement (e.g., via a known dependence of heater resistance with temperature).SUMMARY

[0006] A method for controlling a temperature of a substrate support for a substrate processing system includes setting a temperature of the substrate support in one of Z zones in response to a temperature sensor embedded in the one of the Z zones, where Z is an integer greater than one; setting the temperature of the substrate support in Z-1 zones of the Z zones using Z-1 power ratios, respectively; measuring Z resistances of Z resistive heaters embedded in the Z zones at a first temperature and a second temperature; setting the temperature of the substrate support to a third temperature in response to the temperature sensor and the Z-1 power ratios; determining Z-1 first target resistances for the Z-1 zones, respectively, at the third temperature; measuring the Z resistances of the Z resistive heaters at the third temperature, respectively; and comparing Z-1 resistances of Z-1 resistive heaters for the Z-1 zones and the Z-1 first target resistances at the third temperature, respectively, and selectively adjusting the Z- 1 power ratios in response thereto.

[0007] In other features, the method includes setting the temperature of the substrate support to a fourth temperature in response to the temperature sensor and the Z-1 power ratios; determining Z-1 second target resistances for the Z-1 zones, respectively, at the fourth temperature; measuring the Z resistances of the Z resistive heaters at the fourth temperature, respectively; and comparing Z-1 resistances of Z-1 resistive heaters for the Z-1 zones and the Z-1 second target resistances at the fourth temperature, respectively, and selectively adjusting the Z-1 power ratios in response thereto.

[0008] In other features, the selectively adjusting the Z-1 power ratios iterates until the Z-1 resistances of the Z-1 resistive heaters are within a predetermined range of the Z-1 first target resistances at the third temperature.

[0009] In other features, the method includes storing the Z resistances of the Z resistive heaters in response to the Z-1 resistances of the Z-1 resistive heaters being within the predetermined range of the Z-1 first target resistances at the third temperature. The selectively adjusting the Z-1 power ratios iterates until the Z-1 resistances of the Z-1 resistive heaters are within a predetermined range of the Z-1 second target resistances at the fourth temperature.

[0010] In other features, the method includes storing the Z resistances of the Z resistive heaters in response to the Z-1 resistances of the Z-1 resistive heaters being within the predetermined range of the Z-1 second target resistances at the fourth temperature. The method includes generating a resistance to temperature calibrationtable in response to the stored Z resistances of the Z resistive heaters. The method includes using the resistance to temperature calibration table to control temperature in the Z-1 zones during substrate processing.

[0011] In other features, the Z-1 first target resistances for each of the Z-1 zones are determined in response to a sum of a resistance of a corresponding zone at the first temperature and a product of a difference and a ratio. The difference comprises a resistance of the corresponding zone at the second temperature minus a resistance of the corresponding zone at the first temperature. The ratio comprises a numerator including a difference between a resistance at the one of the Z zones at the third temperature minus a resistance of the one of the Z zones at the first temperature and a denominator including a difference between a resistance at the one of the Z zones at the second temperature minus a resistance of the one of the Z zones at the first temperature.

[0012] In other features, the first temperature and the second temperature are lower than an operating temperature of the substrate support during substrate processing. The first temperature and the second temperature are less than 300QC. The Z-1 zones do not include temperature sensors.

[0013] In other features, the method includes measuring the Z resistances of the Z resistive heaters includes monitoring Z voltages supplied to the Z resistive heaters, respectively; and calculating the Z resistances of the Z zones based on the Z voltages supplied to the Z resistive heaters, respectively.

[0014] In other features, measuring the Z resistances of the Z zones includes monitoring Z currents supplied to the Z resistive heaters, respectively; and calculating the Z resistances based on the Z currents supplied to the Z resistive heaters, respectively.

[0015] In other features, measuring the Z resistances of the Z zones during operation includes monitoring Z currents and Z voltages supplied to Z resistive heaters, respectively; and calculating the Z resistances based on the Z currents and the Z voltages supplied to the Z resistive heaters, respectively. The method includes controlling a temperature of a gas distribution device to a temperature greater than ambient temperature and less than a heated temperature of the substrate support during calibration. The temperature of the gas distribution device is maintained at a temperature less than 90% of the heated temperature of the substrate support during calibration.

[0016] A temperature control system controlling a temperature of a substrate support for a substrate processing system includes a substrate support including Z zones including Z resistive heaters, respectively, where Z is an integer greater than one. A temperature sensor is embedded in the one of the Z zones. A controller is configured to set the temperature of the substrate support in Z-1 zones of the Z zones using Z-1 power ratios, respectively; measure Z resistances of Z resistive heaters embedded in the Z zones at a first temperature and a second temperature; set the temperature of the substrate support to a third temperature in response to the temperature sensor and the Z-1 power ratios; determine Z-1 first target resistances for the Z-1 zones, respectively, at the third temperature; measure the Z resistances of the Z resistive heaters at the third temperature, respectively; and compare Z-1 resistances of Z-1 resistive heaters for the Z-1 zones and the Z-1 first target resistances at the third temperature, respectively, and selectively adjust the Z-1 power ratios in response thereto.

[0017] In other features, the controller is further configured to set the temperature of the substrate support to a fourth temperature in response to the temperature sensor and the Z-1 power ratios; determine Z-1 second target resistances for the Z-1 zones, respectively, at the fourth temperature; measure the Z resistances of the Z resistive heaters at the fourth temperature, respectively; and compare Z-1 resistances of Z-1 resistive heaters for the Z-1 zones and the Z-1 second target resistances at the fourth temperature, respectively, and selectively adjust the Z-1 power ratios in response thereto.

[0018] In other features, the controller is configured to selectively adjust the Z-1 power ratios until the Z-1 resistances of the Z-1 resistive heaters are within a predetermined range of the Z-1 first target resistances at the third temperature.

[0019] In other features, the controller is configured to store the Z resistances of the Z resistive heaters in response to the Z-1 resistances of the Z-1 resistive heaters being within the predetermined range of the Z-1 first target resistances at the third temperature.

[0020] In other features, the controller is configured to selectively adjust the Z-1 power ratios iterates until the Z-1 resistances of the Z-1 resistive heaters are within a predetermined range of the Z-1 second target resistances at the fourth temperature. The controller is configured to store the Z resistances of the Z resistive heaters in response to the Z-1 resistances of the Z-1 resistive heaters being within thepredetermined range of the Z-1 second target resistances at the fourth temperature. The controller is configured to generate a resistance to temperature calibration table in response to the stored Z resistances of the Z resistive heaters. The controller is configured to use the resistance to temperature calibration table to control temperature in the Z-1 zones during substrate processing.

[0021] In other features, the controller is configured to determine the Z-1 first target resistances for each of the Z-1 zones in response to a sum of a resistance of a corresponding zone at the first temperature and a product of a difference and a ratio. The difference comprises a resistance of the corresponding zone at the second temperature minus a resistance of the corresponding zone at the first temperature. The ratio comprises a numerator including a difference between a resistance at the one of the Z zones at the third temperature minus a resistance of the one of the Z zones at the first temperature and a denominator including a difference between a resistance at the one of the Z zones at the second temperature minus a resistance of the one of the Z zones at the first temperature.

[0022] In other features, the first temperature and the second temperature are lower than an operating temperature of the substrate support during substrate processing. The first temperature and the second temperature are less than 300QC. The Z-1 zones do not include temperature sensors.

[0023] In other features, the controller is configured to measure the Z resistances of the Z resistive heaters by monitoring Z voltages supplied to the Z resistive heaters, respectively; and calculating the Z resistances of the Z zones based on the Z voltages supplied to the Z resistive heaters, respectively. The controller is configured to measure the Z resistances of the Z resistive heaters by monitoring Z currents supplied to the Z resistive heaters, respectively; and calculating the Z resistances based on the Z currents supplied to the Z resistive heaters, respectively.

[0024] In other features, the controller is configured to measure the Z resistances of the Z resistive heaters by monitoring Z currents and Z voltages supplied to Z resistive heaters, respectively; and calculating the Z resistances based on the Z currents and the Z voltages supplied to the Z resistive heaters, respectively. The controller is configured to control a temperature of a gas distribution device to a temperature greater than ambient temperature and less than a heated temperature of the substrate support during calibration. The controller is configured to control the temperature of the gasdistribution device at a temperature less than 90% of the heated temperature of the substrate support during calibration.

[0025] 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

[0026] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0027] FIG. 1 is a functional block diagram of an example of a substrate processing system including a dynamic temperature controller for a zoned, temperature-controlled component such as a substrate support according to the present disclosure;

[0028] FIG. 2 is a functional block diagram of an example of a dynamic temperature control system for a component with resistive heater zones according to the present disclosure;

[0029] FIGs. 3A to 3C illustrate examples of substrate supports including multiple heater zones according to the present disclosure;

[0030] FIG. 4 is a graph illustrating resistance of Z resistive heaters in Z zones, respectively, as a function of temperature according to the present disclosure;

[0031] FIGS. 5A to 5C are flowcharts illustrating an example of a method for generating a calibration table for dynamically controlling temperature in Z zones of a substrate support according to the present disclosure; and

[0032] FIG. 6 is a flowchart illustrating an example of a method for dynamically controlling substrate support temperature in the Z zones using a resistance to temperature calibration table of FIGS. 5A to 5C.

[0033] In the drawings, reference numbers may be reused to identify similar and / or identical elements.DETAILED DESCRIPTION

[0034] While the present disclosure includes specific examples relating to temperature control of multiple zones in a substrate support or substrate support of a substrateprocessing system, the systems and methods set forth herein can be applied to control of temperature in other types of components with zoned resistance heating.

[0035] Temperature uniformity is typically desired across the substrate during substrate processing. Power is independently supplied to the resistance heaters in each of the zones. However, the multi-zone heater systems often include only a single thermocouple that is embedded in one of the zones to measure substrate support temperature.

[0036] Power is supplied to the remaining zones at a predetermined ratio of the power (or power ratio) (or a predetermined ratio of duty cycle) supplied to the zone with the thermocouple to maintain the uniform temperature in all of the zones. For example, a power ratio for Z-1 zones of the Z zones includes ratios P2 / P1, P3 / P1, ..., and Pz / Pi. A first zone 1 is supplied power Pi in response to the thermocouple or temperature sensor. The remaining power ratios set power supplied to the Z-1 remaining zones 2, 3, ..., and Z, respectively.

[0037] The power or duty cycle ratios are typically determined for a specific process condition and generally remain unchanged. The actual temperatures in the remaining Z-1 zones are unknown but expected to be within a predetermined range of the zone with the thermocouple. In some applications, however, significant heat load changes can occur during certain process conditions, which can cause the temperatures in one or more of the Z-1 zones to change relative to the zone with the thermocouple. The temperature variation leads to undesirable process control. When the temperature variation is sufficiently high, failure of the substrate support can occur.

[0038] Some heating systems rely on the dependence of the heater coil resistivity with temperature (or temperature coefficient of resistance (TCR)). These systems generally control individual zone temperatures independently and usually require temperature sensors or thermocouples in each zone.

[0039] Individual calibration and / or characterization of the temperature versus resistance for each heater element and their relation to zone temperature can be determined using a substrate with one or more embedded thermocouples arranged in each of the zones of the substrate support. During calibration, power to the heating zones is controlled in response to the temperature sensed by one or more thermocouples in the corresponding zone. The thermocouple substrate is used to measure zone to zone temperature differences based on spatial temperature sensorreadings. Later, the temperature delta between zones is used to control the power delivered to the zones without embedded sensors.

[0040] Using the thermocouple substrate has several disadvantages. The thermocouples in the thermocouple substrate are wired and the processing chamber needs to be opened to place the thermocouple substrate on the substrate support. During calibration, the thermocouple substrate is heated by the substrate support to operating temperature and then cooled down to a safe temperature so that the thermocouple substrate can be removed. This makes the calibration procedure labor intensive and time consuming. The calibration process can take 12 hours due to the long cooldown time of the substrate support to a safe temperature. The thermocouple substrates are costly and unreliable (e.g., some last about 15 calibrations before requiring replacement). Calibration is also sensitive to operating conditions such as showerhead temperature, substrate support-to-showerhead distance, chamber emissivity, chamber pressure, and / or gas species.

[0041] The dynamic temperature control system according to the present disclosure circumvents the above requirements while providing temperature uniformity in multiple zones of the substrate support using a single temperature sensor located in one of the zones. The TCR is a material property that is related to material micro-structure of the resistance heater. Components made of the same material that are produced under the same processing conditions are expected to have the same or close TCR values. In other words, heater coil elements used in resistive heaters that are located in different zones of a multi-zone substrate support and that are processed together are expected to have the same or very close TCR values. In practice, however, the TCR values are not the same which means that the TCR of one resistive heater cannot be used to extrapolate resistances of other resistive heaters.

[0042] Calibration according to the present disclosure does not require the use of the wired thermocouple substrate or the wired thermocouple substrate to be arranged on the substrate support during calibration to generate a resistance to temperature calibration resistance table. During calibration according to the present disclosure, power is initially controlled using to one zone based on the sensed temperature and the power ratio is used to control the power to the remaining Z-1 zones. The resistances of the resistance heaters in the zones are measured at two different temperatures (e.g., temperatures greater than ambient and less than process temperatures (e.g., 100QCand 250QC)). At substrate support temperatures above ambient temperature and less than process temperature, temperature is less sensitive to variations in chamber conditions.

[0043] Power is controlled using the same approach and the substrate is heated to a third temperature that is higher than the first and second temperatures (e.g., near process temperature). After stabilizing at the third temperature, the resistances of the resistive heaters are measured and compared to a predetermined range around a target resistance (generated using a relationship described further below). The power ratio is adjusted until the resistances of the resistive heaters are within a predetermined range of the target resistance. Then all of the resistances of the resistive heaters are stored. The process is repeated for a fourth temperature greater than the third temperature. A resistance to temperature table is updated and used to control temperature in the Z-1 zones during processing.

[0044] As can be appreciated, the calibration that is performed is specific to each zone. In other words, the dynamic temperature control system uses temperature coefficients of resistance a / that are different for each of the resistive heaters. The calibration method according to the present disclosure provides improved temperature control accuracy as compared to systems using resistive ratios determined at a single temperature such as ambient temperature.

[0045] Referring now to FIG. 1 , a substrate processing system 120 is shown. While a processing chamber for chemical vapor deposition (CVD) or atomic layer deposition (ALD) using capacitively coupled plasma (CCP) is shown for purposes of illustration, any other type of substrate processing system can be used.

[0046] The substrate processing system 120 includes a processing chamber 122 that encloses other components of the substrate processing system 120 and contains the RF plasma (if used). The substrate processing system 120 includes an upper electrode 124 and a substrate support 126 such as an electrostatic chuck (ESC), substrate support, etc. During operation, a substrate 128 is arranged on the substrate support 126.

[0047] For example only, the upper electrode 124 may include a gas distribution device 129 such as a showerhead that introduces and distributes process gases. The gas distribution device 129 may include a stem portion including one end connected to a top surface of the processing chamber. A base portion is generally cylindrical andextends radially outwardly from an opposite end of the stem portion at a location that is spaced from the top surface of the processing chamber. A substrate-facing surface or faceplate of the base portion of the showerhead includes a plurality of holes through which precursor, reactants, etch gases, inert gases, carrier gases, other process gases or purge gas flows. Alternately, the upper electrode 124 may include a conducting plate and the process gases may be introduced in another manner.

[0048] The substrate support 126 includes a baseplate 130 that acts as a lower electrode. The baseplate 130 supports a heating plate 132, which may correspond to a ceramic multi-zone heating plate. A thermal resistance layer 134 may be arranged between the heating plate 132 and the baseplate 130. The baseplate 130 may include one or more channels 136 for flowing coolant through the baseplate 130.

[0049] If plasma is used, an RF generating system 140 generates and outputs an RF voltage to one of the upper electrode 124 and the lower electrode (e.g., the baseplate 130 of the substrate support 126). The other one of the upper electrode 124 and the baseplate 130 may be DC grounded, AC grounded or floating. For example only, the RF generating system 140 may include an RF generator 142 that generates RF power that is fed by a matching and distribution network 144 to the upper electrode 124 or the baseplate 130. In other examples, the plasma may be generated inductively or remotely.

[0050] A gas delivery system 150 includes one or more gas sources 152-1 , 152-2, ..., and 152-N (collectively gas sources 152), where N is an integer greater than zero. The gas sources 152 are connected by valves 154-1 , 154-2, ..., and 154-N (collectively valves 154) and MFCs 156-1 , 156-2, ..., and 156-N (collectively MFCs 156) to a manifold 160. While a single gas delivery system 150 is shown, two or more gas delivery systems can be used.

[0051] A dynamic temperature controller 163 is connected to a plurality of resistive heaters 164 arranged in the heating plate 132. The dynamic temperature controller 163 is also connected to a thermocouple 165 arranged in one of a plurality of heating zones in the heating plate 132. In some examples, the remaining heating zones do not include thermocouples. The dynamic temperature controller 163 may be used to control power to the plurality of resistive heaters 164 to adjust and control a temperature of the substrate support 126 and the substrate 128.

[0052] In some examples, the dynamic temperature controller 163 and / or another controller may also communicate with a coolant assembly 166 to control coolant flow through the channels 136. For example, the coolant assembly 166 may include a coolant pump, a reservoir and / or one or more thermocouples. In some examples, the dynamic temperature controller 163 operates the coolant assembly 166 to selectively flow the coolant through the channels 136 to cool the substrate support 126.

[0053] A valve 170 and pump 172 may be used to evacuate reactants from the processing chamber 122. A system controller 180 may be used to control components of the substrate processing system 120 in accordance with a recipe. In some examples, the showerhead may include cooling channels and / or resistive heaters to heat the showerhead to a predetermined temperature.

[0054] Referring now to FIG. 2, a dynamic temperature control system 200 according to the present disclosure is shown. The dynamic temperature control system 200 includes a power supply 220 including driver circuits 224-1 , 224-2, ..., and 224-N (collectively driver circuits 224) where N is an integer greater than one. The driver circuits 224 control power to resistive heaters as will be described further below.

[0055] Current output by the driver circuits 224-1 , 224-2, ..., and 224-N to each of the zones is monitored by current sensors 228-1 , 228-2, ..., and 228-N (collectively current sensors 228). Voltage output by the driver circuits 224-1 , 224-2, ..., and 224-N to each of the zones is monitored by voltage sensors 230-1 , 230-2, ..., and 230-N (collectively voltage sensors 230).

[0056] A component 231 includes heated zones 232-1 , 232-2, ..., and 232-N (collectively zones 232). In the description that follows, the component 231 includes a substrate support. However, any heated component with multiple zones with resistive heaters can be used. Each of the zones 232-1 , 232-2, ..., and 232-N includes a resistive heater 236-1 , 232-2, ..., and 232-N (collectively resistive heaters 236) that is embedded therein. In some examples, the resistive heaters 236 include a heater element or coil having a corresponding resistance. One of the zones 232-1 , 232-2, ..., and 232-N includes a thermocouple 240 for sensing a temperature thereof. Remaining ones of the zones 232-1 , 232-2, ..., and 232-N do not include thermocouples.

[0057] The controller 250 communicates with the current sensors 228 and / or the voltage sensors 230, the thermocouple 240 and the driver circuits 224. The controller 250 includes a heater control module 254. The heater control module 254 determinesthe resistance of each of the resistive heaters 236 based upon the respective current and / or voltage measurements from the current sensors 228 and / or the voltage sensors 230. In some examples, the current sensors 228 can be omitted when the current is held sufficiently constant by the power supply 220 and the voltage is varied to control RF power. In other examples, the voltage sensors 230 can be omitted when the voltage is held sufficiently constant by the power supply 220 and current is varied to control RF power.

[0058] The heater control module 254 monitors the temperature of one of the zones 232 with the thermocouple 240 (e.g., the zone 232-1 ) and controls power to the zone based on the temperature feedback from the thermocouple 240. The heater control module 254 measures the resistance of the Z-1 zones and uses a target resistance in the resistance to temperature calibration table to control power to the corresponding zone. The heater control module 254 controls the driver circuits 224 in the remaining zones 232 to increase or decrease power to achieve the desired resistances, which creates a uniform temperature in all of the remaining zones 232.

[0059] Referring now to FIGs. 3A to 3C, examples of zones of a substrate support are shown. While specific examples are shown, other zone layouts can be used. In FIG. 3A, a substrate support 310 includes concentric zones including zone 1 , zone 2 and zone 3. Each of the zones includes a resistance heater. In FIG. 3B, a substrate support 350 includes resistive heater coils defining an inner zone 360 and an outer zone 362. In FIG. 3C, an inner zone 1 of a substrate support 370 is surrounded by circumferential outer zones 2, 3, 4, and 5. Each of the zones includes a resistance heater. As can be appreciated, other zone layouts can be used.

[0060] Referring now to FIG. 4, graphs illustrating resistance as a function of temperature for a multi-zone heater are shown. The resistive heaters have a linear relationship between resistance and temperature:where a / is a temperature coefficient of resistance for each of / zones (e.g., a constant that is independent of temperature). As noted above, the TCRs ai can be different for each of the different zones.

[0061] Referring now to FIG. 5, a method 400 for generating a calibration table for dynamic temperature controller is shown. In some examples, the method 400 is used tocontrol the temperature of multiples zones of the component to a uniform temperature using one or more thermocouple(s) associated with only one of the zones. At 410, substrate support temperature is set to temperature T1 in zone 1 in response to a temperature sensed by a temperature sensor such as a thermocouple. Temperatures in other zones are set using a power ratio for each zone as described above. The temperature of the showerhead is set to Tsi. At 414, after waiting for the temperature of the substrate support to stabilize, resistances (RI_TI to RZ_TI ) of resistance heaters in each of the Z zones of the substrate support at the temperature T1 are measured and stored.

[0062] At 418, substrate support temperature is set to temperature T2 in zone 1 in response to the temperature sensed by the temperature sensor. Temperatures in other zones are set using the power ratio. The temperature of the showerhead is set to Ts2. At 420, after waiting for the temperature to stabilize, resistances (RI_T2 to RZ_T2) of resistance heaters in each of the Z zones of the substrate support at the temperature T2 are measured and stored. A ratio of changes in the resistances (RI_TI to RZ_TI and RI_T2 to RZ_T2) of resistance heaters are used during further calibration below.

[0063] Subsequently, the ratio of changes in the resistances (RI_TI to RZ_TI and RI_T2 to RZ_T2) is used during calibration at third and fourth temperatures T3 and T4. Once the resistances at T3 and T4 are known, then the resistance to temperature calibration table can be generated (since two points define a linear relationship).The substrate support is set to temperature T3 in zone 1 in response to the temperature sensed by the temperature sensor. The showerhead is set to temperature Tsa. Temperatures in other zones are set using the power ratio. At 430, the method calibrates at a third temperature T3 with RP_T3 set equal to:

[0064] The relationship is used to determine a target value for the resistance RP_T3, which is compared to the measured resistance. After waiting a predetermined period for temperature to stabilize at T3, the resistances (RI_T3 to Rz ra) are measured and stored at 432. At 438, for each zone, the method determines whether a given zone temperature RP_T3 is within a predetermined range of:

[0065] If RP_T3 for a given zone is greater than an upper limit of the predetermined range as determined at 442, the power ratio for the zone is decreased at 446. If RP_T3 is less than a lower limit of the predetermined range as determined at 442, the power ratio for the zone is increased at 448. The increase (or decrease) can be fixed, a percentage of a difference between measured and target resistance, and / or another function can be used. Control continues from 446 and 448 with 430 and the process iterates until RP_T3 is within the predetermined range as determined at 438. When 438 is true, the method records the resistances (RI_T3 to Rz ra) for T3 at 450.

[0066] The process is repeated with the substrate support at a fourth temperature T4 and the showerhead at temperature Ts4. At 460, the method calibrates at the fourth temperature T4 with RP_T4 set equal to:

[0067] After waiting a predetermined period for temperature to stabilize, the resistances (RI_T4 to RZ_T4) are measured and stored at 464. At 468, for each zone, the method determines whether a given zone temperature RP_T4 is within a predetermined range of:

[0068] If RP_T4 for each zone is greater than an upper limit of the predetermined range as determined at 472, the power ratio for the zone is decreased at 474. If RP_T4 for each zone is less than a lower limit of the predetermined range as determined at 472, the power ratio for the zone is increased at 476. Control continues from 474 and 476 with 460. The process iterates until RP_T4 for the zone is within the predetermined range as determined at 468. When 468 is true, the method records the resistances (RI_T4 to RZ_T4) at 480.

[0069] At 484, the method updates the resistance to temperature calibration table for each zone (e.g., based on a line passing through resistance at T3 and T4 for the zone). The substrate processing system is ready to operate using the resistance to temperature calibration table.

[0070] In some examples, the first temperature T1 and the second temperature T2 are less the third temperature T3 and the fourth temperature T4. In some examples, thefirst temperature T1 and the second temperature T2 are greater than ambient temperature and less than process temperature. In some examples, the first temperature T1 is in a range from 80QC to 130QC (e.g., 100QC) and is less than the second temperature T2. In some examples, the second temperature T2 is in a range from 130QC to 300QC (e.g., 250QC) and is greater than the first temperature T1 by greater than 50QC. In some examples, the first temperature T1 and the second temperature T2 are at least 50QC less than the process temperature.

[0071] In some examples, the third temperature T3 is in a range from 320QC to 550QC (e.g., 400QC or 550QC) and is less than the fourth temperature T4. In some examples, the fourth temperature T4 is in a range from 380QC to 700QC (e.g., 550QC or 670QC) and is greater than the third temperature T3 by greater than 50QC.

[0072] In some examples, the showerhead temperatures Tsi, Ts2, Tsa, and Ts4 are generally set to temperatures less than the substrate support temperatures (e.g., at least 10% to 30% less). For example, when the first temperature T1 is 100QC, the showerhead temperature Tsi can be set to 80QC. For example, when the second temperature T2 is 250QC, the showerhead temperature Ts2 can be set to 200QC. A higher temperature difference may occur for higher temperatures since the showerhead may have a maximum operating temperature. For example, when the third temperature T3 is 400QC or 550QC, the showerhead temperature Tsa can be set to 250QC. For example, when the fourth temperature T4 is 550QC or 670QC, the showerhead temperature Ts4 can be set to 250QC.

[0073] Referring now to FIG. 6, a method 500 for controlling a temperature using the resistance to temperature calibration table is shown. At 510, the method determines whether substrate support temperature control is on. If 510 is true, the method continues at 520 and sets a temperature of substrate support to a temperature setpoint based on temperature sensed by thermocouple in one of the zones and the power ratios. At 524, the method measures resistances of resistive heaters in Z-1 zones. At 528, the method determines a target resistance for each zone at the measured temperature from the resistance to temperature calibration table indexed by the measured and / or setpoint temperature and the zone. At 532, the method adjusts power to resistive heaters in other zones based on target resistance from resistance to temperature calibration table for the zone and the measured temperature and the method returns to 510.

[0074] 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.

[0075] 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, but can also be 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.”

[0076] 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, dependingon 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.

[0077] 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.

[0078] 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. Insome 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.

[0079] 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.

[0080] 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.

Claims

CLAIMSWhat is claimed is:

1. A method for controlling a temperature of a substrate support for a substrate processing system, comprising: setting a temperature of the substrate support in one of Z zones in response to a temperature sensor embedded in the one of the Z zones, where Z is an integer greater than one; setting the temperature of the substrate support in Z-1 zones of the Z zones using Z-1 power ratios, respectively; measuring Z resistances of Z resistive heaters embedded in the Z zones at a first temperature and a second temperature; setting the temperature of the substrate support to a third temperature in response to the temperature sensor and the Z-1 power ratios; determining Z-1 first target resistances for the Z-1 zones, respectively, at the third temperature; measuring the Z resistances of the Z resistive heaters at the third temperature, respectively; and comparing Z-1 resistances of Z-1 resistive heaters for the Z-1 zones and the Z-1 first target resistances at the third temperature, respectively, and selectively adjusting the Z-1 power ratios in response thereto.

2. The method of claim 1 , further comprising: setting the temperature of the substrate support to a fourth temperature in response to the temperature sensor and the Z-1 power ratios; determining Z-1 second target resistances for the Z-1 zones, respectively, at the fourth temperature; measuring the Z resistances of the Z resistive heaters at the fourth temperature, respectively; and comparing Z-1 resistances of Z-1 resistive heaters for the Z-1 zones and the Z-1 second target resistances at the fourth temperature, respectively, and selectively adjusting the Z-1 power ratios in response thereto.

3. The method of claim 1 , wherein the selectively adjusting the Z-1 power ratios iterates until the Z-1 resistances of the Z-1 resistive heaters are within a predetermined range of the Z-1 first target resistances at the third temperature.

4. The method of claim 3, further comprising storing the Z resistances of the Z resistive heaters in response to the Z-1 resistances of the Z-1 resistive heaters being within the predetermined range of the Z-1 first target resistances at the third temperature.

5. The method of claim 2, wherein the selectively adjusting the Z-1 power ratios iterates until the Z-1 resistances of the Z-1 resistive heaters are within a predetermined range of the Z-1 second target resistances at the fourth temperature.

6. The method of claim 5, further comprising storing the Z resistances of the Z resistive heaters in response to the Z-1 resistances of the Z-1 resistive heaters being within the predetermined range of the Z-1 second target resistances at the fourth temperature.

7. The method of claim 6, further comprising generating a resistance to temperature calibration table in response to the stored Z resistances of the Z resistive heaters.

8. The method of claim 7, further comprising using the resistance to temperature calibration table to control temperature in the Z-1 zones during substrate processing.

9. The method of claim 1 , wherein: the Z-1 first target resistances for each of the Z-1 zones are determined in response to a sum of a resistance of a corresponding zone at the first temperature and a product of a difference and a ratio, the difference comprises a resistance of the corresponding zone at the second temperature minus a resistance of the corresponding zone at the first temperature, andthe ratio comprises a numerator including a difference between a resistance at the one of the Z zones at the third temperature minus a resistance of the one of the Z zones at the first temperature and a denominator including a difference between a resistance at the one of the Z zones at the second temperature minus a resistance of the one of the Z zones at the first temperature.

10. The method of claim 1 , wherein the first temperature and the second temperature are lower than an operating temperature of the substrate support during substrate processing.11 . The method of claim 1 , wherein the first temperature and the second temperature are less than 300QC.

12. The method of claim 1 , wherein the Z-1 zones do not include temperature sensors.

13. The method of claim 1 , wherein measuring the Z resistances of the Z resistive heaters includes: monitoring Z voltages supplied to the Z resistive heaters, respectively; and calculating the Z resistances of the Z zones based on the Z voltages supplied to the Z resistive heaters, respectively.

14. The method of claim 1 , wherein measuring the Z resistances of the Z zones includes: monitoring Z currents supplied to the Z resistive heaters, respectively; and calculating the Z resistances based on the Z currents supplied to the Z resistive heaters, respectively.

15. The method of claim 1 , wherein measuring the Z resistances of the Z zones during operation includes: monitoring Z currents and Z voltages supplied to Z resistive heaters, respectively; and calculating the Z resistances based on the Z currents and the Z voltages supplied to the Z resistive heaters, respectively.

16. The method of claim 1 , further comprising controlling a temperature of a gas distribution device to a temperature greater than ambient temperature and less than a heated temperature of the substrate support during calibration.

17. The method of claim 16, wherein the temperature of the gas distribution device is maintained at a temperature less than 90% of the heated temperature of the substrate support during calibration.

18. A temperature control system controlling a temperature of a substrate support for a substrate processing system, comprising: a substrate support including Z zones including Z resistive heaters, respectively, where Z is an integer greater than one; a temperature sensor embedded in the one of the Z zones; and a controller configured to: set the temperature of the substrate support in Z-1 zones of the Z zones using Z-1 power ratios, respectively; measure Z resistances of Z resistive heaters embedded in the Z zones at a first temperature and a second temperature; set the temperature of the substrate support to a third temperature in response to the temperature sensor and the Z-1 power ratios; determine Z-1 first target resistances for the Z-1 zones, respectively, at the third temperature; measure the Z resistances of the Z resistive heaters at the third temperature, respectively; and compare Z-1 resistances of Z-1 resistive heaters for the Z-1 zones and the Z-1 first target resistances at the third temperature, respectively, and selectively adjust the Z-1 power ratios in response thereto.

19. The temperature control system of claim 18, wherein the controller is further configured to: set the temperature of the substrate support to a fourth temperature in response to the temperature sensor and the Z-1 power ratios; determine Z-1 second target resistances for the Z-1 zones, respectively, at the fourth temperature;measure the Z resistances of the Z resistive heaters at the fourth temperature, respectively; and compare Z-1 resistances of Z-1 resistive heaters for the Z-1 zones and the Z-1 second target resistances at the fourth temperature, respectively, and selectively adjust the Z-1 power ratios in response thereto.

20. The temperature control system of claim 18, wherein the controller is configured to selectively adjust the Z-1 power ratios until the Z-1 resistances of the Z-1 resistive heaters are within a predetermined range of the Z-1 first target resistances at the third temperature.21 . The temperature control system of claim 20, wherein the controller is configured to store the Z resistances of the Z resistive heaters in response to the Z-1 resistances of the Z-1 resistive heaters being within the predetermined range of the Z-1 first target resistances at the third temperature.

22. The temperature control system of claim 19, wherein the controller is configured to selectively adjust the Z-1 power ratios iterates until the Z-1 resistances of the Z-1 resistive heaters are within a predetermined range of the Z-1 second target resistances at the fourth temperature.

23. The temperature control system of claim 22, wherein the controller is configured to store the Z resistances of the Z resistive heaters in response to the Z-1 resistances of the Z-1 resistive heaters being within the predetermined range of the Z-1 second target resistances at the fourth temperature.

24. The temperature control system of claim 23, wherein the controller is configured to generate a resistance to temperature calibration table in response to the stored Z resistances of the Z resistive heaters.

25. The temperature control system of claim 24, wherein the controller is configured to use the resistance to temperature calibration table to control temperature in the Z-1 zones during substrate processing.

26. The temperature control system of claim 18, wherein the controller is configured to: determine the Z-1 first target resistances for each of the Z-1 zones in response to a sum of a resistance of a corresponding zone at the first temperature and a product of a difference and a ratio, wherein the difference comprises a resistance of the corresponding zone at the second temperature minus a resistance of the corresponding zone at the first temperature, and wherein the ratio comprises a numerator including a difference between a resistance at the one of the Z zones at the third temperature minus a resistance of the one of the Z zones at the first temperature and a denominator including a difference between a resistance at the one of the Z zones at the second temperature minus a resistance of the one of the Z zones at the first temperature.

27. The temperature control system of claim 18, wherein the first temperature and the second temperature are lower than an operating temperature of the substrate support during substrate processing.

28. The temperature control system of claim 18, wherein the first temperature and the second temperature are less than 300QC.

29. The temperature control system of claim 18, wherein the Z-1 zones do not include temperature sensors.

30. The temperature control system of claim 18, wherein the controller is configured to measure the Z resistances of the Z resistive heaters by: monitoring Z voltages supplied to the Z resistive heaters, respectively; and calculating the Z resistances of the Z zones based on the Z voltages supplied to the Z resistive heaters, respectively.

31. The temperature control system of claim 18, wherein the controller is configured to measure the Z resistances of the Z resistive heaters by: monitoring Z currents supplied to the Z resistive heaters, respectively; and calculating the Z resistances based on the Z currents supplied to the Z resistive heaters, respectively.

32. The temperature control system of claim 18, wherein the controller is configured to measure the Z resistances of the Z resistive heaters by: monitoring Z currents and Z voltages supplied to Z resistive heaters, respectively; and calculating the Z resistances based on the Z currents and the Z voltages supplied to the Z resistive heaters, respectively.

33. The temperature control system of claim 18, wherein the controller is configured to control a temperature of a gas distribution device to a temperature greater than ambient temperature and less than a heated temperature of the substrate support during calibration.

34. The temperature control system of claim 33, wherein the controller is configured to control the temperature of the gas distribution device at a temperature less than 90% of the heated temperature of the substrate support during calibration.

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