Thermoelectric cooling pedestal for substrate processing system

Abstract

[Solution] The temperature control pedestal includes a pedestal, temperature sensors that detect N temperatures within the N zones, and N temperature control devices disposed within the N zones, respectively. A voltage source selectively supplies power to the N temperature control devices. A controller is configured to cause the voltage source to control the temperatures within the N zones by: a) determining a hottest zone among the N zones based on the N temperatures; b) increasing cooling for the hottest zone among the N zones using one of the N temperature control devices if the hottest zone among the N zones has not yet cooled; c) decreasing cooling for the N zones when the temperatures of the N zones are lower than a first temperature setpoint; and d) repeating a) to c) until all of the N zones have temperatures equal to or lower than the first temperature setpoint.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Application No. 62 / 874,649, filed July 16, 2019. The entire disclosures of the above-referenced applications are incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates to substrate processing systems, and more particularly to a thermoelectric cooling pedestal with closed loop zone control for a substrate processing system. [Background technology]

[0003] The background description provided herein is intended to provide a general overview of the contents of the present disclosure. Work by the currently named inventors within the scope of what is described in this Background section, as well as aspects of the description that may not otherwise be regarded as prior art at the time of filing, are not admitted, expressly or impliedly, as prior art against the present disclosure.

[0004] Substrate processing systems are used to perform processes on substrates, such as semiconductor wafers. Examples of processes include deposition, etching, ashing, and other processes. Substrate processing systems include a process chamber or load lock and a pedestal. The substrate is placed on the pedestal during processing. The substrate is exposed to one or more gas mixtures. In some examples, a plasma can be used to cause a chemical reaction.

[0005] In some processes, the substrate is heated to a relatively high temperature during processing. For example, the substrate may be heated to a temperature of 600° C.-700° C. during processing in the processing chamber. After processing in the processing chamber, the substrate may be moved to a cooling pedestal to cool the substrate to a lower temperature. Cooling the substrate in a post-processing station (such as a cooling pedestal using water or other coolant in a load lock) may take a relatively long time, reducing the throughput of the process. Water-cooled pedestals may not be efficient at high temperatures due to evaporation. In addition, sudden cooling of a hot substrate induces stresses in the substrate. Summary of the Invention

[0006] A temperature-controlled pedestal for cooling a substrate includes a pedestal including N zones, where N is an integer greater than 1, a temperature sensor that senses N temperatures within each of the N zones, and N temperature control devices disposed within each of the N zones. A voltage source selectively supplies power to the N temperature control devices. A controller is configured to cause the voltage source to control temperatures within the N zones by a) determining a hottest zone among the N zones based on the N temperatures, b) increasing cooling to the hottest zone among the N zones using one of the N temperature control devices if the hottest zone among the N zones has not yet been cooled, c) decreasing cooling to the N zones when the temperature of the N zones is lower than a first temperature setpoint, and d) repeating a)-c) until all of the N zones have temperatures equal to or lower than the first temperature setpoint.

[0007] In other features, the N temperature control devices comprise Peltier devices. The N relays are connected to the controller. The N switches selectively connect voltage sources to the N temperature control devices.

[0008] In other features, the controller controls the duty cycles of the N switches using the N relays. The voltage source includes a fixed voltage source. The voltage source includes a variable voltage source, further comprising N H-bridges respectively connected between the voltage source and the N temperature control devices.

[0009] In other features, the controller is configured to select a first mode of the N H-bridges for cooling and a second mode of the N H-bridges for heating. The controller is further configured to select the second mode of the N H-bridges and heat the sensing layer to a second temperature setpoint when the substrate is removed, the second temperature setpoint being higher than the first temperature setpoint.

[0010] In other features, the controller is further configured to control temperatures in the N zones when the substrate is removed by: e) determining a coolest zone of the N zones based on the N temperatures; f) increasing heating to the coolest zone of the N zones using one of the N temperature control devices if the coolest zone of the N zones is not yet heated; g) decreasing heating to the N zones when the temperature of the N zone is greater than a second temperature setpoint; and h) repeating e)-g) until all of the N zones have a temperature greater than or equal to the second temperature setpoint.

[0011] In other features, when another substrate is placed on the pedestal, the controller is further configured to decrease the temperature in the N zones by increasing the voltage output to the N temperature control devices. The controller increases the voltage output by a predetermined amount at a predetermined interval. The predetermined amount and the predetermined interval are fixed.

[0012] In other features, the controller increases the voltage output in T discrete steps in response to the temperature of the pedestal falling below T predetermined temperatures, where T is an integer greater than one.

[0013] In other features, a heat sink is disposed adjacent to the pedestal. A fan is disposed adjacent to the heat sink. A cold plate is disposed adjacent to the heat sink. The temperature sensor comprises N temperature sensors disposed in the pedestal. The temperature sensor comprises one or more infrared sensors that sense temperatures in the N zones. The temperature sensor comprises a thermal camera that generates a thermal image, and the N temperatures for the N zones are respectively based on the thermal image.

[0014] Other areas of applicability of the present disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. [Brief description of the drawings]

[0015] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0016] [Figure 1] FIG. 1 is a side cross-sectional view of an example cooling pedestal according to the present disclosure.

[0017] [Diagram 2] FIG. 2 is a top view of an example cooling pedestal according to the present disclosure. [Diagram 3] FIG. 3 is a top view of an example cooling pedestal according to the present disclosure. [Figure 4] FIG. 4 is a top view of an example cooling pedestal according to the present disclosure. [Diagram 5] FIG. 5 is a top view of an example cooling pedestal according to the present disclosure.

[0018] [Figure 6] FIG. 6 is a functional block diagram of an example control system for a cooling pedestal according to the present disclosure.

[0019] [Figure 7] FIG. 7 is a flow chart of an example of a method for controlling the cooling pedestal of FIG. 6 according to the present disclosure.

[0020] [Figure 8] FIG. 8 is a functional block diagram of another example of a control system for a cooling pedestal in accordance with the present disclosure.

[0021] [Figure 9A] FIG. 9A is a flow chart of an example of a method for controlling cooling of the cooling pedestal of FIG. 8 according to the present disclosure.

[0022] [Figure 9B] FIG. 9B is a graph showing the voltage output of the voltage source as a function of pedestal temperature.

[0023] [Figure 9C] FIG. 9C is a graph showing the voltage output of a voltage source as a function of time in accordance with the present disclosure.

[0024] [Figure 10] FIG. 10 is a flow chart of an example of a method for controlling heating of the cooling pedestal of FIG. 8 according to the present disclosure.

[0025] [Figure 11] FIG. 11 is a side cross-sectional view of an example cooling pedestal with a thermal camera according to the present disclosure.

[0026] In the drawings, reference numbers may be reused to refer to similar and / or identical elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] In some processes, the substrate is heated to a relatively high temperature during processing. For example, the substrate may be heated to a temperature of 600° C.-700° C. during processing in the processing chamber. After processing in the processing chamber, the substrate may be moved to a cooling pedestal to cool the substrate to a lower temperature. Cooling the substrate in a post-processing station (such as a cooling pedestal using water or other coolant in a load lock) may take a relatively long time, reducing the throughput of the process. Water-cooled pedestals may not be efficient at high temperatures due to evaporation. In addition, sudden cooling of a hot substrate induces stresses in the substrate.

[0028] While cooling the substrate, care must be taken not to damage the substrate. For example, temperature differences at different parts of the substrate can cause damage such as cracks (e.g., due to temperature gradients from the center to the edge). In addition, a large difference between the substrate temperature just after processing and the temperature of the cooling pedestal can cause damage such as cracks. In other words, a very hot substrate placed on a very cold pedestal can cause the substrate to crack.

[0029] When the substrate is placed on the pedestal, temperature sensors start cooling in all zones (to a setpoint temperature). If the temperature of one or more of the zones drops compared to the other zones, one or more zones are switched off until all of the zones' temperatures are approximately equal (within a predefined range). Once all of the zones' temperatures are equal, the previously turned off zone or zones are turned on again to reach their setpoint temperature. This loop continues until all of the zones have uniformly reached their setpoint temperature. This approach limits the temperature difference from one zone to another and avoids cracks.

[0030] 1, a cooling pedestal assembly 120 for a substrate 128 according to the present disclosure is shown. The cooling pedestal assembly 120 primarily cools the substrate, although in some examples, the cooling pedestal assembly 120 provides heating during periods when the substrate 128 is not positioned on the cooling pedestal assembly 120.

[0031] The cooling pedestal assembly 120 includes a sensing layer 130 and a base 136. The sensing layer 130 includes one or more temperature sensors 132. The sensing layer 130 is disposed adjacent to the base 136. In some examples, the base 136 includes one or more temperature control devices 138. The temperature control devices 138 also provide cooling when the substrate 128 is disposed on the cooling pedestal assembly 120. In some examples, the temperature control devices 138 also provide heating when the substrate 128 is not disposed on the cooling pedestal assembly 120.

[0032] In some examples, the temperature control device 138 includes a Peltier device. A thermal grease layer 134 may be positioned between the temperature control device 138 and the base 136. The temperature control device 138 is sandwiched between the heat sink 142 and the thermal grease layer 134, which clamps the temperature control device 138 between the heat sink 142 and the base 136, and contact conduction occurs. Because the thermal grease layer 134 or clamp is used instead of an adhesive, it allows the temperature control device 138 to contract and expand with temperature fluctuations, which reduces stress-induced failure. A fan or cold plate 150 may be positioned adjacent to the heat sink 142 to increase airflow and cooling, respectively, to the temperature control device 138.

[0033] 2-5, examples of cooling pedestal assemblies 120 are shown. In FIG. 2, the temperature control devices 138 are arranged in a square pattern. In FIG. 3, the temperature control devices 138 of FIG. 2 are further arranged in a square zone. In FIG. 4, the temperature control devices 138 are arranged in a circular pattern. In FIG. 5, the temperature control devices 138 of FIG. 4 are further arranged in a circular zone.

[0034] 6, a temperature control system 600 for the cooling pedestal assembly 120 is shown. The temperature control system 600 implements a preset temperature control. The temperature control system 600 includes a controller 610 and a voltage source 620. The voltage source 620 provides a single voltage output for all zones. In some examples, the voltage output may be adjusted depending on the measured pedestal temperature and / or the amount of time since the substrate has been placed on the pedestal for cooling.

[0035] In the following example, three zones are described. However, N zones may be used, where N is an integer greater than 1. The controller 610 uses first, second, and third relays R1, R2, and R3 to control the duty cycles of first, second, and third switches Sw1, Sw2, and Sw3, respectively. The switches Sw1, Sw2, and Sw3 connect the voltage source 620 to the temperature control devices 138 in the first, second, and third zones Z1, Z2, and Z3.

[0036] The temperature control system 600 of Figure 6 can be used for low temperature substrates. A voltage source 620 powers the temperature control devices in zones Z1, Z2, and Z3 to maintain the pedestal temperature at a temperature setpoint (e.g., 20°C). When a hot substrate is placed on the cooling pedestal assembly 120, the substrate 128 increases the temperature of the cooling pedestal assembly 120. The temperature control device 138 provides cooling to reduce the temperature of the cooling pedestal assembly 120 to a first temperature setpoint.

[0037] A lower substrate temperature is less likely to cause cracking of the substrate due to thermal stress, therefore the hot substrate can be placed directly on the cooling pedestal.

[0038] The temperature control system 600 includes a relay for each zone. For example, relays R1, R2, and R3 and switches Sw1, Sw2, and Sw3 control the cooling in each of zones Z1, Z2, and Z3, respectively. The controller 610 sends signals to relays R1, R2, and / or R3 based on input from temperature sensors 132 located in zones Z1, Z2, and Z3, respectively. Relays R1, R2, and R3 control the duty cycle for zones Z1, Z2, and Z3. Varying the duty cycle helps maintain a uniform temperature across all of the zones of the pedestal while decreasing the temperature.

[0039]

[0041] Referring now to Figure 7, a method 700 for controlling the cooling pedestal assembly of Figure 6 is shown. At 714, all zone temperatures are read. At 718, the zone temperatures are compared to the setpoint temperature. At 722, the method determines whether at least one of the zone temperatures is greater than the setpoint temperature. If 722 is false, the method continues to 723. Once all of the zones have reached the setpoint temperature, the substrate is removed from the pedestal and the method ends.

[0040] If 722 is true, the method identifies the hottest of the zones at 724. At 726, the method determines whether the hottest zone is already cooled. If 726 is false, the method increases the duty cycle for the hottest zone at 728 and the method continues to 730. At 730, the method determines whether all zone temperatures are equal (within a predetermined temperature difference from each other (0.5° C., 1° C., 2° C., 3° ​​C., 4° C., 5° C., etc.)) and higher than the setpoint temperature. If 730 is true, then the method increases the duty cycle of the center zone at 731 and the method continues to 732. At 732, the method determines whether any of the zone temperatures are lower than the setpoint temperature. If 732 is true, the method reduces the duty cycle for the zones whose temperatures are lower than the setpoint temperature at 736. If 732 is false, the method continues to 722.

[0041] 8, there is shown a variable voltage based temperature control system 800 for the cooling pedestal assembly 120. The temperature control system 800 includes a controller 810 that compares zone temperatures and generates an output signal to a voltage source 820 that supplies an individual voltage to each zone. The controller 810 varies the duty cycle for each zone and provides a variable voltage to each zone based on the zone temperature.

[0042] The first, second, and third outputs of the variable voltage source 820 are output to the first, second, and third H-bridges 822-1, 822-2, and 822-3, respectively. The first, second, and third H-bridges 822-1, 822-2, and 822-3 have an inverting (heating) state and a non-inverting (cooling) state. When in the inverting state, the first, second, and third H-bridges 822-1, 822-2, and 822-3 selectively invert the output of the variable voltage source 820 to the temperature control devices in all zones. The outputs of the first, second, and third H-bridges 822-1, 822-2, and 822-3 are connected to the temperature control devices in the zones Z1, Z2, and Z3, respectively.

[0043] The temperature control system includes a variable voltage source 820. The voltage varies based on the temperature measured in the corresponding one of zones Z1, Z2, and Z3. When the temperature is changed in any zone, the duty cycle and voltage output changes accordingly.

[0044] When a hot substrate is placed on the pedestal, a sensor detects the presence of the substrate and sends a substrate present (SP) signal to the controller 810. A temperature sensor measures the temperature and sends a signal to the controller 810. The controller 810 determines the hottest zone and starts cooling the hottest zone. The duty cycle of the temperature control devices is directly controlled by the controller 810. For example, the voltage change corresponds to a predefined value. For example, to change from 325°C to 315°C, the voltage is set to 12V. This process continues for a predefined period or cycle of the controller 810 and temperature uniformity is maintained across the zones while increasing or decreasing the temperature as needed. Also, the output voltage for each zone is independent of the other output voltages.

[0045] Once the substrate has cooled to a first setpoint temperature ST1 (e.g., 20° C.), the substrate is transported for further processing. The sensor detects that the substrate has been removed and transitions the SP signal. The controller adjusts the target temperature of the pedestal to a second setpoint temperature ST2 (e.g., 35° C.). The H-bridge is changed to inverting mode, heating the pedestal from the first temperature setpoint (ST1) to the second temperature setpoint (ST2).

[0046] 9A-10, a method for controlling the cooling and / or heating of the cooling pedestal of FIG. 8 is shown. In FIG. 9A, the method 900 determines at 910 whether a substrate is positioned on the pedestal. If 910 is true, the method continues at 914 by setting the H-bridge in a non-inverting (cooling) mode. At 918, the zone temperatures are read. At 922, the zone temperatures are compared to a first setpoint temperature ST1. At 926, the method determines whether at least one of the zone temperatures is higher than the first setpoint temperature ST1. If 926 is false, the method continues at 927 where the substrate is moved off the pedestal (all zones have reached the setpoint temperature ST1) and the method ends. Otherwise, the method identifies at 928 the hottest of the zones. At 930, the method determines whether the hottest zone has already been cooled. If 930 is false, the method cools the hottest zone at 932 and continues at 933. At 933, the method determines whether all zone temperatures are greater than or equal to the setpoint temperature ST1. If 933 is true, the method increases the duty cycle of the center zone at 934 and the method continues at 936. At 936, the method determines whether any of the zone temperatures are less than the first setpoint temperature ST1. If 936 is true, the method reduces the duty cycle for zones whose temperatures are less than the first setpoint temperature ST1. The method returns to 926.

[0047] In FIG. 9B, a graph shows the voltage output by the voltage source to the temperature control device as a function of pedestal temperature. The voltage supplied can be gradually changed in steps while the substrate cools. Once the pedestal temperature is reached, the voltage output by the voltage source can be increased to the next voltage output. This process can be repeated until the setpoint temperature ST1 is reached.

[0048] In FIG. 9C, a graph shows the voltage output by the voltage source to the temperature control device as a function of time since the substrate is placed on the cooling pedestal. The voltage supplied can be gradually changed in steps while the substrate is cooling. When the next period is reached, the voltage output by the voltage source can be increased to the next voltage output. This process can be repeated until the setpoint temperature ST1 is reached.

[0049] In Figure 10, the method 1000 determines at 1010 whether the substrate is positioned on the pedestal. If 1010 is false, the method continues at 1014 by setting the H-bridge to the inverting (heating) mode. At 1018, the zone temperatures are read. At 1022, the zone temperatures are compared to a second setpoint temperature ST2. At 1026, the method determines whether at least one of the zone temperatures is less than the second setpoint temperature ST2. In some examples, the second setpoint temperature ST2 is greater than the first setpoint temperature ST1.

[0050] If 1026 is false, the method continues at 1028 where the substrate is removed from the pedestal (all zones have reached the setpoint temperature ST2) and the method ends. Otherwise, the method identifies the coolest one of the zones at 1029. At 1030, the method determines whether the coolest zone is already heated. If 1030 is false, the method heats the coolest zone at 1032 and continues at 1034. At 1034, the method determines whether all zone temperatures are below the setpoint temperature ST2. If 1034 is true, the method increases the duty cycle of the central zone at 1036 and the method continues at 1040. At 1040, the method determines whether any of the zone temperatures are higher than the second setpoint temperature ST2. If 1040 is true, the method stops heating the zone whose temperature is higher than the second setpoint temperature ST2. The method returns to 1026.

[0051] 11, the temperature sensor may be replaced by one or more thermal sensors 1110, such as one or more infrared (IR) sensors or thermal cameras, disposed above the substrate. The IR sensors generate IR data that is output to a controller. The thermal camera generates a thermal image of the substrate and outputs thermal imaging data to the controller. The temperature in the zone is determined from the IR data and / or thermal image. The controller adjusts the heating or cooling in the zone to maintain a uniform temperature across the substrate. In other words, the power is varied to vary the zone temperature, such that the temperature across the substrate (as seen in the thermal image or IR data) is the same (uniform).

[0052] The foregoing description is merely exemplary in nature and is not intended to limit the disclosure, its application, or uses in any way. The broad teachings of the disclosure can be embodied in various forms. Thus, while the disclosure includes specific examples, the true scope of the disclosure should not be limited to such examples, since other modifications will become apparent upon review of the drawings, specification, and claims that follow. It should be understood that one or more steps in a method may be performed in different orders (or simultaneously) without altering the principles of the disclosure. Furthermore, although each embodiment is described above as having certain features, any one or more of these features described with respect to any embodiment of the disclosure can be implemented in other embodiments and / or combined with any features of the other embodiments (even if such combination is not explicitly described). In other words, the described embodiments are not mutually exclusive, and it is within the scope of the disclosure to substitute one or more embodiments for one another.

[0053] Spatial and functional relationships between elements (e.g., modules, circuit elements, semiconductor layers, etc.) are described using various terms such as "connected," "engaged," "coupled," "adjacent," "next to," "on," "above," "below," and "disposed." Also, when a relationship between a first element and a second element is described in the above disclosure, unless expressly described as "direct," the relationship may be a direct relationship in which there are no other intervening elements between the first element and the second element, but may also be an indirect relationship in which there are one or more intervening elements (spatial or functional) between the first element and the second element. As used herein, the phrase at least one of A, B, and C should be interpreted in the sense of a logic (A or B or C) using a non-exclusive logical OR, and not in the sense of "at least one of A, at least one of B, and at least one of C."

[0054] In some implementations, the controller is part of a system, and such a system may be part of the examples described above. Such a system 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 (wafer pedestals, gas flow systems, etc.). These systems may be integrated with electronics for controlling system operations before, during, and after processing of a semiconductor wafer or substrate. Such electronics may be referred to as a "controller" and may control various components or subparts of one or more systems. The controller may be programmed to control any of the processes disclosed herein depending on the processing requirements and / or type of system. Such processes may include delivery of process 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, position and motion settings, wafer loading and unloading from the tool, and wafer loading and unloading from other transport tools and / or load locks connected or interfaced with the particular system.

[0055] Broadly, a controller may be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. 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, i.e., 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) that define operational parameters for performing a particular process on or for a semiconductor wafer or for a system. The operational parameters may, in some embodiments, 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.

[0056] The controller, in some embodiments, may be part of, coupled to, or a combination of a computer that is integrated or coupled with the system or otherwise networked to the system. For example, the controller may be in the "cloud" or all or part of a fab host computer system. This allows for remote access of wafer processing. The computer may allow remote access to the system to monitor the current progress of a fabrication operation, review the history of past fabrication operations, review trends or performance criteria from multiple fabrication operations, modify parameters of a current process, set processing steps following a current process, or start a new process. In some examples, a remote computer (e.g., a server) may provide a process recipe to the system over a network. Such a network may include a local network or the Internet. The remote computer may include a user interface that allows entry or programming of parameters and / or settings, which are then communicated from the remote computer to the system. In some examples, the controller receives instructions in the form of data. Such data identifies parameters for each processing step performed during one or more operations. It should be understood that the parameters may be specific to the type of process being performed and the type of tool that the controller is configured to interface with or control. Thus, as discussed above, the controller may be distributed, for example, by having one or more individual controllers networked together and working together toward a common purpose (such as the processes and controls described herein). An example of a distributed controller for such purposes would include one or more integrated circuits on 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) and coupled to control the process in the chamber.

[0057] Exemplary systems may include, but are not limited to, 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 tracking chamber or module, and any other semiconductor processing system that may be associated with or used in the fabrication and / or manufacturing of semiconductor wafers.

[0058] As described above, depending on the process step or steps being performed by the tool, the controller may communicate with one or more other tool circuits or 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 for 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] A temperature controlled pedestal for cooling a substrate, comprising: N zones, where N is an integer greater than 1; temperature sensors for sensing N temperatures within the N zones, respectively; N temperature control devices disposed within the N zones, respectively; A base including: a voltage source selectively supplying power to the N temperature control devices; a) determining a hottest zone among the N zones based on the N temperatures; b) increasing cooling to the hottest one of the N zones using one of the N temperature control devices if the hottest one of the N zones has not yet been cooled; c) decreasing cooling to the N zones when the temperature of the N zones is less than a first temperature setpoint; d) repeating a) through c) until all of the N zones have a temperature equal to or less than the first temperature setpoint. and a controller configured to cause the voltage source to control a temperature within the N zones by: [Form 2] The temperature control base according to aspect 1, A temperature control pedestal, wherein the N temperature control devices comprise Peltier devices. [Form 3] The temperature control base according to aspect 1, further comprising: N relays connected to the controller; and N switches selectively connecting the voltage source to the N temperature control devices. [Form 4] The temperature control base according to aspect 3, The controller controls the duty cycles of the N switches using the N relays. [Form 5] The temperature control base according to aspect 3, The temperature controlled pedestal, wherein the voltage source comprises a fixed voltage source. [Form 6] The temperature control base according to aspect 1, The temperature control pedestal further comprises N H-bridges, the voltage source including a variable voltage source, each H-bridge connected between the voltage source and the N temperature control devices. [Form 7] The temperature control base according to claim 6, The temperature control pedestal, wherein the controller is configured to select a first mode of the N H-bridges for cooling and a second mode of the N H-bridges for heating. [Form 8] The temperature control base according to aspect 7, The controller: Once the board is removed, Selecting the second mode of the N H-bridges; Heating the sensing layer to a second temperature setpoint The method further comprises: the second temperature set point is higher than the first temperature set point; Temperature controlled pedestal. [Form 9] The temperature control base according to aspect 8, When the board is removed, the controller e) determining a coolest zone of the N zones based on the N temperatures; f) increasing heating to the coldest one of the N zones using one of the N temperature control devices if the coldest one of the N zones is not already heated; g) decreasing heating to the N zones when the temperature of the N zones is greater than the second temperature setpoint; h) repeating e) through g) until all of the N zones have a temperature equal to or greater than the second temperature setpoint. a temperature control pedestal further configured to control the temperature within the N zones by [Form 10] The temperature control base according to aspect 9, A temperature controlled pedestal, wherein when another substrate is placed on the pedestal, the controller is further configured to decrease the temperature in the N zones by increasing a voltage output to the N temperature control devices. [Form 11] The temperature control base according to claim 10, The controller increases the voltage output by a predetermined amount at predetermined intervals. [Form 12] The temperature control base according to claim 11, The predetermined amount and the predetermined interval are fixed. [Form 13] The temperature control base according to claim 10, The controller increases the voltage output in T discrete steps in response to the temperature of the pedestal falling below T predetermined temperatures, where T is an integer greater than one. [Form 14] The temperature control base according to aspect 1, further comprising: A temperature controlled pedestal comprising a heat sink disposed adjacent to the pedestal. [Form 15] The temperature control base according to aspect 14, further comprising: A temperature controlled pedestal comprising a fan disposed adjacent to the heat sink. [Form 16] The temperature control base according to aspect 14, further comprising: A temperature controlled pedestal comprising a cold plate disposed adjacent to the heat sink. [Form 17] The temperature control base according to aspect 1, A temperature controlled pedestal, wherein the temperature sensor comprises N temperature sensors disposed within the pedestal. [Form 18] The temperature control base according to aspect 1, The temperature controlled pedestal, wherein the temperature sensor comprises one or more infrared sensors for sensing temperatures within the N zones. [Form 19] The temperature control base according to aspect 1, The temperature controlled pedestal, wherein the temperature sensor comprises a thermal camera that generates a thermal image, and the N temperatures for the N zones are respectively based on the thermal images.

Claims

1. A temperature controlled pedestal for cooling a substrate, comprising: N zones, where N is an integer greater than 1; temperature sensors for sensing N temperatures within the N zones, respectively; N temperature control devices disposed within the N zones, respectively; A base including: a voltage source for selectively supplying power to the N temperature control devices; a) determining a hottest zone among the N zones based on the N temperatures; b) increasing cooling to the hottest one of the N zones using one of the N temperature control devices if the hottest one of the N zones has not yet been cooled; c) decreasing cooling to any of the N zones whose temperature is below the first temperature setpoint when the temperature of any of the N zones is below the first temperature setpoint; d) repeating a) through c) until all of the N zones have a temperature less than or equal to the first temperature setpoint. and a controller configured to cause the voltage source to control a temperature within the N zones by:

2. 2. The temperature controlled base of claim 1, A temperature controlled pedestal, wherein the N temperature control devices comprise Peltier devices.

3. 2. The temperature controlled base of claim 1, further comprising: N relays connected to the controller; and N switches selectively connecting the voltage source to the N temperature control devices.

4. 4. The temperature controlled base according to claim 3, The controller controls the duty cycles of the N switches using the N relays.

5. 4. The temperature controlled base according to claim 3, The temperature controlled pedestal, wherein the voltage source comprises a fixed voltage source.

6. 2. The temperature controlled base of claim 1, The temperature control pedestal further comprises N H-bridges, the voltage source including a variable voltage source, each H-bridge connected between the voltage source and the N temperature control devices.

7. 7. The temperature controlled base of claim 6, The temperature control pedestal, wherein the controller is configured to select a first mode of the N H-bridges for cooling and a second mode of the N H-bridges for heating.

8. 8. The temperature controlled base of claim 7, The controller: Once the board is removed, selecting the second mode of the N H-bridges; Heating the sensing layer to a second temperature setpoint. The method further comprises: the second temperature set point is higher than the first temperature set point; Temperature controlled pedestal.

9. 9. The temperature controlled base of claim 8, When the board is removed, the controller e) determining a coolest zone of the N zones based on the N temperatures; f) increasing heating to the coolest one of the N zones using one of the N temperature control devices if the coolest one of the N zones is not already heated; g) decreasing heating to the zones having a temperature greater than the second temperature setpoint when the temperature of any of the N zones is greater than the second temperature setpoint; h) repeating e) through g) until all of the N zones have a temperature equal to or greater than the second temperature setpoint. a temperature control pedestal further configured to control the temperature within the N zones by

10. 10. The temperature controlled base of claim 9, A temperature controlled pedestal, wherein when another substrate is placed on the pedestal, the controller is further configured to decrease the temperature in the N zones by increasing a voltage output to the N temperature control devices.

11. 11. The temperature controlled base of claim 10, The controller increases the voltage output by a predetermined amount at predetermined intervals.

12. 12. The temperature controlled base of claim 11, The predetermined amount and the predetermined interval are fixed.

13. 11. The temperature controlled base of claim 10, A temperature controlled pedestal, wherein the controller increases the voltage output in T discrete steps in response to the temperature of the pedestal falling below T predetermined temperatures, where T is an integer greater than one.

14. 2. The temperature controlled base of claim 1, further comprising: A temperature controlled pedestal comprising a heat sink disposed adjacent to the pedestal.

15. 15. The temperature controlled base of claim 14, further comprising: A temperature controlled pedestal comprising a fan disposed adjacent to the heat sink.

16. 15. The temperature controlled base of claim 14, further comprising: A temperature controlled pedestal comprising a cold plate disposed adjacent to the heat sink.

17. 2. The temperature controlled base of claim 1, A temperature controlled pedestal, wherein the temperature sensor comprises N temperature sensors disposed within the pedestal.

18. 2. The temperature controlled base of claim 1, The temperature controlled pedestal, wherein the temperature sensor comprises one or more infrared sensors for sensing temperatures within the N zones.

19. 2. The temperature controlled base of claim 1, A temperature controlled pedestal, wherein the temperature sensor comprises a thermal camera that generates a thermal image, and the N temperatures for the N zones are respectively based on the thermal images.

Images