Patent Publication Number: US-2018040496-A1

Title: Electrostatic chuck system and control method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Korean Patent Application No. 10-2016-0099592, filed on Aug. 4, 2016, and entitled, “Electrostatic Chuck System and Control Method Thereof,” is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     One or more embodiments described herein relate to an electrostatic chuck system and a method for controlling an electrostatic chuck system. 
     2. Description of the Related Art 
     Semiconductor manufacturing equipment is used to perform various processes on a wafer. The position of the wafer in a processing chamber should be fixed to provide stability. An electrostatic chuck may be used to fix the wafer. 
     One type of electrostatic chuck includes a heater and chiller to control wafer temperature during a semiconductor process. The heater includes an array of resistors in a matrix. Each resistor blocks power interference or power coupling with a physically adjacent resistor using a diode. However, the resistor array may be sintered at a high temperatures during mass production. The diode may be adversely affected or modified at these high temperatures, thus diminishing wafer reliability. 
     SUMMARY 
     In accordance with one or more embodiments, an electrostatic chuck system includes a first heater including a plurality of resistors connected to a plurality of row wiring lines and a plurality of column wiring lines in a matrix form; a second heater under the first heater and including a heater electrode in a concentric shape or a spiral shape; a chiller under the second heater to chill the first heater or the second heater; and a first controller to control the first heater, the second heater, and the chiller, wherein the first controller is to switch the row wiring lines and the column wiring lines of the first heater in a time-division manner to provide a power pulse to heat the resistors and a detect pulse to monitor a real-time resistance value or a real-time temperature of each of resistors connected to selected row wiring lines. 
     In accordance with one or more other embodiments, a method for controlling a heater array, which includes a plurality of resistors arranged in a matrix, each of the resistors excluding and is not connected to a semiconductor rectifying device, the method comprising: computing a duty time of each of a plurality of row switches and a plurality of column switches based on mutual power coupling of the resistors, the row and column switches supplying electric power to heat each of the resistors; applying electric power to the resistors by sequentially turning on the row switches and the column switches based on the duty time; applying a detect pulse to each of the resistors; and estimating a real-time resistance value or a real-time temperature of each of the resistors with reference to the detect pulse. 
     In accordance with one or more other embodiments, an electrostatic chuck system including an electrostatic chuck includes a micro heater and a macro heater, the micro heater including a plurality of resistors connected in a matrix form and the macro heater including a heater electrode in a concentric shape or a spiral shape; and a controller to control heating power to the micro heater or the macro heater, wherein the controller is to provide a time-division power pulse, to which mutual power coupling among the resistors is applied, provide a detect pulse to detect a characteristic change of each of the resistors, and update a pulse width of the power pulse based on a response to the detect pulse. 
     In accordance with one or more other embodiments, an electrostatic chuck system including a first heater including a plurality of resistors; a second heater adjacent to the first heater; a chiller adjacent to the second heater; and a controller to control the first heater, the second heater, and the chiller, wherein the resistors exclude and are not connected to semiconductor rectifying devices and wherein the controller is to generate control information to control heat to be generated from the resistors. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features will become apparent to those of skill in the art by describing in detail exemplary embodiments with reference to the attached drawings in which: 
         FIG. 1  illustrates an embodiment of an electrostatic chuck system; 
         FIG. 2  illustrates an embodiment of an electrostatic chuck; 
         FIG. 3  illustrates an embodiment of a micro heater and a micro driver; 
         FIG. 4  illustrates current paths formed according to an embodiment; 
         FIG. 5  illustrates a determinant illustrating a relationship between duty times of switch control signals, whole electric power, and power consumption according to an embodiment; 
         FIG. 6  illustrates power pulses according to an embodiment; 
         FIGS. 7A-7D  illustrate an embodiment of a method for applying a detect pulse to a heater array; 
         FIG. 8  illustrates an embodiment of a method for driving a micro heater; 
         FIG. 9  illustrates an embodiment of an operation of the method in  FIG. 8 ; 
         FIG. 10  illustrates another embodiment of a method for driving a micro heater; 
         FIG. 11  illustrates another embodiment of a micro heater and micro driver; 
         FIG. 12  illustrates a determinant of a duty time of a power pulse for controlling a micro heater in  FIG. 11  according to an embodiment; 
         FIG. 13  illustrates another embodiment of a micro heater; 
         FIG. 14  illustrates an embodiment of independent heater arrays of a micro heater; and 
         FIGS. 15 and 16  illustrate embodiments of a method for arranging resistors of a micro heater. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a cross-sectional view of an embodiment of an electrostatic chuck system  100  which includes an electrostatic chuck  110  and a control unit  190 . The electrostatic chuck  110  may include a micro heater  120 , a macro heater  130 , and a chiller  140 . The control unit  190  may include a micro driver  150 , a macro driver  160 , a chiller driver  170 , and a controller  180 . 
     A wafer  101  may be fixed on the electrostatic chuck  110 . For example, an electrostatic force may fix the wafer  101  to the electrostatic chuck  110  when a high constant voltage is applied to the electrostatic chuck  110 . The electrostatic chuck  110  may compensate for a temperature deviation between areas on the wafer  101  through the micro heater  120 , the macro heater  130 , and the chiller  140 . 
     The micro heater  120  may include a heater array  121  in a matrix structure. The heater array  121  which may finely adjust the temperature of a target point without using a semiconductor device, e.g., a diode or transistor. In one embodiment, a plurality of resistors, arranged in a row direction and a column direction, generate heat based on applied electric power. A power pulse having a certain duty time or a duty ratio may be provided to a resistor at an intersection of a selected row and a selected column of the micro heater  120 . The power pulse may be provided through the micro driver  150 . 
     The resistors of the micro heater  120  may have, for example, the same resistance value. However, characteristics of the resistors of the micro heater  120  may vary as the result of error in a manufacturing process and real-time peripheral environment effects. The change in characteristics of the resistors may cause, for example, the resistance value of a resistor to change or may effect a temperature changer or heat to be generated. 
     According to an embodiment, a detect pulse DP for estimating a real-time resistance value or a real-time temperature is applied to the resistors of the micro heater  120 . The controller  180  receives a result obtained based on applying the detect pulse DP. The controller  180  may estimate a real-time resistance value or a real-time temperature of each resistor of the micro heater  120  through the detect pulse DP. The controller  180  may then adjust the duty time of the power pulse based on the estimated real-time resistance value or the estimated real-time temperature. 
     The macro heater  130  may control the temperature of a relatively wide area compared to the micro heater  120 . In one embodiment, the macro heater  130  may include a heater electrode formed according to a geometric shape of the electrostatic chuck  110 . For example, the macro heater  130  may include a heater electrode having a spiral or concentric shape, instead of a point shape. In one embodiment, the macro heater  130  may include heater electrodes of an array shape for heating a wider area than an area heated by the micro heater  130 . 
     In one embodiment, the macro heater  130  may have a heater electrode with a concentric shape. For example, the macro heater  130  may include heater electrodes  131   a ,  131   b ,  133   a , and  133   b  arranged in a concentric direction in the electrostatic chuck  110  having a disk shape. The heater electrodes  131   a  and  131   b  indicate resistor sections forming one concentric circle (e.g., an outer concentric circle). The heater electrodes  133   a  and  133   b  indicate resistor sections forming an inner concentric circle. The number of heater electrodes in a concentric shape or the arrangement shape of the heater electrodes may be different in other embodiments, for example, based on the kind of semiconductor process, a wafer size, or other factors. 
     The chiller  140  chills the electrostatic chuck  110  when heated to a high temperature. The electrostatic chuck  110  may be used, for example, in a plasma processing apparatus that processes the wafer  110  using plasma. When the interior of a chamber in which the electrostatic chuck  110  is installed is set in a high-temperature environment and the wafer  101  is exposed to high-temperature plasma, the wafer  101  may be experience damage, for example, from ion bombardment. Thus, the wafer  101  may be chilled by the chiller  140  to prevent the wafer  101  from being damages and to allow for uniform plasma processing. 
     In order to chill the wafer  101 , a refrigerant flows through channels  141  to  146  in the chiller  140 . The refrigerant may include, for example, water, ethylene glycol, silicon oil, liquid Teflon, or a mixture of water and glycol. In addition to the refrigerant, the channels  141  to  146  may be implemented with thermoelectric cooling devices to adsorb peripheral heat according to applied electric power. The chiller  140  may be provided with the refrigerant from the chiller driver  170  and/or with cooling power under control of the controller  180 . 
     Cooling or heating of the electrostatic chuck  110  may be controlled by the control unit  110 , that includes the micro driver  150 , the macro driver  160 , the chiller driver  170 , and the controller  180 . 
     The micro driver  150  provides the micro heater  120  with a power pulse PP having a pulse width controlled by the controller  180 . The micro driver  150  may provide the power pulse PP to each of the resistors of the heater array  121 . The power pulse PP has a duty time DT and is provided under control of the controller  180  The micro driver  150  may include a switch unit that selects rows and columns of the heater array  121 . The switching time of each switch of the switch unit may be determined according to the duty time DT calculated in the controller  180  or may be predetermined. 
     The macro driver  160  adjusts the temperature of the macro heater  130  under control of the controller  180 . The macro driver  160  may perform temperature adjustment on areas of a relatively wide range compared to the micro heater  120 . For example, under control of the controller  160 , the macro driver  160  may supply electric power to the heater electrodes  131   a ,  131   b ,  133   a , and  133   b  in the concentric direction. The macro driver  160  may provide electric power of different levels to the heater electrodes  131   a  and  131   b , which constitute an outer concentric circle, and the heater electrodes  133   a  and  133   b , which constitute an inner concentric circle. 
     The chiller driver  170  may pump the refrigerant into the channels  141  to  146  under control of the controller  180 . For example, the chiller driver  170  may uniformly supply the refrigerant to the chiller  140  to maintain temperature equilibrium of the chamber. The chiller driver  170  may include, for example, a pump to pressurize fluid such as a refrigerant. When the chiller  140  includes a cooling device that adsorbs peripheral heat by electric energy, the chiller driver  170  may supply or switch electric power under control of the controller  180 . 
     To adjust a temperature of the electrostatic chuck  110 , the controller  180  may control the micro driver  150 , the macro driver  160 , and the chiller driver  170 . The controller  180  may be, for example, a management server or computer that controls a semiconductor manufacturing process. The controller  180  may monitor the state of the electrostatic chuck  110  and may control the micro driver  150 , the macro driver  160 , and the chiller driver  170  based on the monitoring result. In addition, the controller  180  may monitor a real-time resistance value or temperature of each heater electrode with reference to a response RES of the micro heater  120  to the detect pulse DP. The controller  180  may compensate a temperature of a specific area or a resistance value of a heater electrode using the above-described monitoring result. 
     The controller  180  may include a duty time table  182  and a temperature/resistance estimator  184 . The duty time table  182  stores the duty time DT, which, for example, may be indicative of the width of the power pulse PP applied to resistors in each area of the micro heater  120 . The duty time DT of the power pulse PP may be determined, for example, based on interferences among the resistors of the micro heater  120 . The duty time DT may be stored in the duty time table  182  and periodically updated. The temperature/resistance estimator  184  may estimate a real-time resistance value or a real-time temperature of the micro heater  120  with reference to the response RES to the detect pulse DP. The temperature/resistance estimator  184  computes the duty time DT to compensate for the real-time resistance value or real-time temperature of each resistor of the micro heater  120 . The controller  180  may update the duty time table  182  with the computed duty time. Afterwards, the power pulse PP to be provided to the micro heater  120  may be generated based on the updated duty time DT. 
     The electrostatic chuck system  100  may include the micro heater  120  that does not include a semiconductor device. In addition, the electrostatic chuck system  100  may provide the power pulse PP determined based on the power coupling among resistors in the heater array  121 . Also, the electrostatic chuck system  100  may provide the detect pulse DP for monitoring a resistance value or a real-time temperature of each resistor in the heater array  121 . The electrostatic chuck system  100  may periodically update duty time information of the power pulse PP, which the micro driver  150  supplies, with reference to a response to the detect pulse DP. 
     In accordance with the present embodiment, the electrostatic chuck  110  may not use a semiconductor device such as a diode or temperature sensor for measuring a temperature of a specific time point. Thus, the electrostatic chuck system  100  may have the ability achieve control at high temperatures and with a simple design. 
       FIG. 2  illustrates an embodiment of the electrostatic chuck  110  including the micro heater  120 , the macro heater  130 , and the chiller  140  in a disk shape. The electrostatic chunk  110  may further include an adsorption electrode on or over the micro heater  120  to adsorb the wafer  101  (refer to  FIG. 1 ) with the electrostatic force when a constant voltage is provided. An electrostatic dielectric for providing electrical isolation may be between the adsorption electrode and the micro heater  120 . An electrical isolation material having a specific thermal conductivity may be between the micro heater  120  and the macro heater  130 . Materials having predetermined thermal conductivities corresponding to a desired application may be between the macro heater  130  and the chiller  140 . 
     In the above-described structure, a uniform temperature distribution may be generated on the entire area of the wafer  101  using the micro heater  120  and the macro heater  130 . For example, as the temperature of a specific area of the micro heater  120  increases, it may be difficult to maintain a target temperature (e.g., even when the power pulse PP is almost not supplied). In the case, the temperature may be reduced by activating the chiller  140 . Based on the reduced temperature, dynamic temperature control may be performed through coarse temperature control of the macro heater  130  and fine temperature control of the micro heater  120 . 
     The electrostatic chuck  110  includes the chiller  140  and a dual heater of the micro heater  120  and the macro heater  130  with heater electrodes of different control ranges and shapes. In another embodiment, the number of heaters and/or number of chillers may be different (e.g., more or less) based on the intended application. 
       FIG. 3  illustrates a combination of the micro heater  120  and the micro driver  150  according to an embodiment. The heater array  121  includes a plurality of resistors arranged in rows and columns, a row switch  151  for selecting the rows, a column switch  153  for selecting the columns, and a voltage source  155 . In this example, the heater array  121  includes 16 resistors R 0  to R 15  arranged in a 4-by-4 matrix. Each of the resistors R 0  to R 15  of the heater array  121  may not include a semiconductor rectifying device. e.g., a diode. Accordingly, the heater array  121  may be easy to manufacture and may have a uniform physical characteristic. The heater array  121  may have a different number of resistors in another embodiment. 
     The row switch  151  and the column switch  153  select the rows and columns of the heater array  121 , respectively. Switches SW_A, SW_B, SW_C, and SW_D of the row switch  151  are controlled by a first switch control signal SCS_R from the controller  180 . Switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  of the column switch  153  are controlled by a second switch control signal SCS_C from the controller  180 . 
     The voltage source  155  may be connected with a plurality of resistors by the row switch  151  and the column switch  153 . For example, the switch SW_A and the switch SW_ 1  may be simultaneously turned on by the first switch control signal SCS_R and the second switch control signal SCS_C. 
     In the case where a rectifying device (e.g., a diode) is connected to each of the resistors R 0  to R 15 , only resistor R 0  selected by the switches SW_A and SW_ 1  may be supplied with electric power after being connected to the voltage source  155 . However, when a rectifying device is not included, various current paths may be formed between the switch SW_A and the switch SW_ 1 . Power consumption or heat generation occurs at each of resistors through which a current path is formed. Each of the switch control signals SCS_R and SCS_C may include a pulse to compensate for the above-described power interference. 
       FIG. 4  illustrates an embodiment of equivalent circuit diagram of various current paths that may be formed when the switches SW_A and SW_ 1  of  FIG. 3  are turned on. Referring to  FIG. 4 , the level of a voltage across each of the resistors R 0  to R 15  may be computed at a time point at which the switches SW_A and SW_ 1  are turned on. The electric power consumed by the respective resistors R 0  to R 15  may be computed by the voltages across the resistors R 0  to R 15 . 
     In one embodiment, the electric power consumed by the resistor R 0  at a time point at which the switches SW_A and SW_ 1  are turned on may be computed by (V1−V8) 2 /R 0 . The electric power consumed by the resistor R 4  at a time point at which the switches SW_A and SW_ 1  are turned on may be computed by (V2−V5) 2 /R 4 . Voltages V1 to V8 of nodes corresponding to opposite ends of the respective resistors R 0  to R 15  may be computed, for example, using algorithms based on circuit analysis theory. The electric power consumed by each of the resistors R 0  to R 15  may be expressed as a magnitude relative to the entire electric power P ON  supplied to the heater array  121 . 
     The electric power applied to each of the resistors R 0  to R 15  may be converted by Joule heating to thermal energy. An area corresponding to each of the resistors R 0  to R 15  is heated by the Joule heating. The temperature of each of the resistors R 0  to R 15  is controlled by controlling the turn-on time of corresponding ones of the row and column switches  151  and  153 . In addition, if the electric power consumed by each of the resistors R 0  to R 15  is known through a combination of the row switch  151  and the column switch  153 , the turn-on times of the row switch  151  and the column switch  153  may be calculated to maintain a target temperature. 
     In the present embodiment, the electric power consumed by each of the resistors R 0  to R 15  may be computed to maintain a specific temperature, with respect to all combinations of the row switch  151  and the column switch  153 . The switch control signals SCS_R and SCS_C for providing a turn-on period for each combination of the row switch  151  and the column switch  153  may be provided with reference to the computed electric power. In this case, the power pulse PP, to which the power coupling is applied, may have a duty time set to correspond to a pulse width of each of the switch control signals SCS_R and SCS_C. 
       FIG. 5  illustrates a determinant corresponding to a relationship between duty times of the switch control signals SCS_R and SCS_C, to which the power coupling of the heater array  121  of  FIG. 3  is applied, the entire electric power PON, and power consumption of each resistor. Duty times D(a, 1 ), D(a, 2 ), . . . , D(d, 4 ) of the switch control signals SCS_R and SCS_C for controlling all switches of the row switch  151  and the column switch  153  nay correspond to  FIG. 5 . 
     In this embodiment, the electric power P 1  consumed by the resistor R 1  under the condition of  FIG. 4  may be expressed by Equation 1. 
     
       
         
           
             
               
                 
                   
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     In Equation 1, K (1,1)  indicates a ratio of electric power consumed by a resistor at the first row and first column. Electric power P 0  and P 2  to P 15  consumed by the remaining resistors R 0  and R 2  to R 15  may be respectively expressed by a value relative to the entire electric power P ON . According to Equation 1, the duty times of the switch control signals SCS_R and SCS_C may be computed based on mutual power interference using the electric power to heat each resistor. Since the determinant is used for iterative computation, the determinant may depend on computation of a computer. 
       FIG. 6  illustrates an embodiment of power pulses applied to resistors. Referring to  FIG. 6 , during a period in which one of the row switches SW_A, SW_B, SW_C, and SW_D is turned on, column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  may be turned on according to duty times, for example, corresponding to  FIG. 5 . In addition, when application of the power pulses to resistors in any one row is completed, all the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are turned on and the detect pulse DP is applied to the heater array  121 . 
     At time T 0 , the row switch SW_A and the column switch SW_ 1  are turned on. The row switch SW_A maintains a turn-on state during a given time period ΔT. The time period ΔT includes a time period in which the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are sequentially turned on according to allocated duty times and are then turned on at the same time for the detect pulse DP. 
     While the row switch SW_A is turned on, the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are turned off after being respectively turned on by the pulse widths corresponding to specific duty times D(a, 1 ), D(a, 2 ), D(a, 3 ), and D(a, 4 ) from time points T 0 , T 1 , T 2 , and T 3 . The electric power computed based on power coupling at a turn-on time point of each of the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  may be supplied to the resistors R 0  to R 15 . Afterwards, at time T 4 , the detect pulse DP is provided to the heater array  121  while the row switch SW_A and all the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are turned on. In this case, the current flowing through each of the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  may be measured. 
     At time T 5 , the row switch SW_B and the column switch SW_ 1  are turned on. While the row switch SW_B is turned on, the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are sequentially turned on at time points T 0 , T 1 , T 2 , and T 3  during allocated duty times D(b, 1 ), D(b, 2 ), D(b, 3 ), and D(b, 4 ). At T 9 , the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are simultaneously turned on to apply the detect pulse DP. 
     In the present embodiment, the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are turned on based on allocated duty times while each of the row switches SW_C and SW_D is turned on. The column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  may be simultaneously turned on to apply the detect pulse DP while each of the row switches SW_C and SW_D is turned on. The power pulse PP having a duty time according to the present embodiment is supplied to the heater array  121  in the above-described manner. In addition, the detect pulse DP is applied to the heater array  121  at a time point at which the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are simultaneously turned on while one row is selected, and a current or voltage signal that is generated according to the detect pulse DP is stored as a response signal to the detect pulse DP. In this case, the stored response signal may be used as data for estimating a real-time resistance value and a real-time temperature of each resistor in a selected row. 
       FIGS. 7A-7D  illustrate an embodiment of a method for applying detect pulse DP to the heater array  121 . Referring to  FIGS. 7A to 7D , the detect pulse DP may be applied when all column switches are turned on and any one row switch is turned on. 
       FIG. 7A  illustrates a switching state of the heater array  121  at a time point T 4  (e.g., refer to  FIG. 6 ) at which all the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are turned on while the row switch SW_A is turned on. When the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are simultaneously turned on while row switch SW_A is turned on, currents I a1 , I a2 , I a3 , and I a4  flow through the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4 , respectively. The currents I a1 , I a2 , I a3 , and I a4  correspond to currents flowing through the resistors RA 1 , RA 2 , RA 3 , RA 4 , respectively. The controller  180  may measure levels of the currents and may store the measured current levels. 
       FIG. 7B  illustrates a switching state of the heater array  121  at a time point T 9  (e.g., refer to  FIG. 6 ) at which all the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are turned on while the row switch SW_B is turned on. When the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are simultaneously turned on while row switch SW_B is turned on, currents I b1 , I b2 , I b3 , and I b4  flow through the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4 , respectively. The currents I b1 , I b2 , I b3 , and I b4  correspond to currents flowing through the resistors RB 1 , RB 2 , RB 3 , RB 4 , respectively. The controller  180  may measure levels of the currents and may store the measured current levels. 
       FIG. 7C  illustrates that it is possible to measure currents I c1 , I c2 , I c3 , and I c4  flowing through the resistors RC 1 , RC 2 , RC 3 , and RC 4 .  FIG. 7D  illustrates that it is possible to measure currents I d1 , I d2 , I d3 , and I d4  flowing through the resistors RD 1 , RD 2 , RD 3 , and RD 4 . A current flowing through each resistor may be used to calculate a real-time resistance value based on a relationship with an applied voltage. When the power pulse PP is applied to the heater array  121 , the heater array  121  may be variably affected by various peripheral environmental conditions such as a heating temperature and a pressure in a chamber. A resistance value or temperature in real time may be compensated based on measurement of the real-time resistance value. 
       FIG. 8  illustrates an embodiment of a method for driving the micro heater  120 . Referring to  FIG. 8 , the electrostatic chuck system  100  may monitor a temperature of the heater array  121  in real time and may again set the duty time of the power pulse PP to be applied through each switch based on the monitoring result. 
     In operation S 110 , the electric power of a given level may be applied to the macro heater  130  under control of the controller  180  (e.g., refer to  FIG. 1 ). A refrigerant for cooling may, of course, be supplied to the chiller  140 . 
     In operation S 120 , the controller  180  may control the micro driver  150  to apply the power pulse PP for heating the micro heater  120 . The controller  180  may control the micro driver  150  so that a duty time of the power pulse PP to be supplied to the micro heater  120  is set to a default value D(r,c) stored in the duty time table  182 . The duty time D(r,c) corresponding to the default value may correspond to a value determined in a process of manufacturing the electrostatic chuck system  100 . In addition to providing the power pulse PP, the controller  180  may apply the detect pulse DP to estimate the real-time resistance value or a real-time temperature of each resistor. The detect pulse DP may be applied to the heater array  121  after the power pulse PP is provided to heat each resistor. The time point at which the detect pulse DP is applied may be different in another embodiment. 
     In operation S 130 , the controller  180  estimates a real-time resistance value of each resistor based on the detect pulse DP. For example, the controller  180  may compute a resistance value of each resistor of the heater array  121  with reference to a current value sampled by the detect pulse DP. Thus, a real-time resistance value of each resistor may be estimated using a level of a voltage applied by the detect pulse DP and a level of a current flowing through each corresponding resistor. 
     In operation S 140 , the controller  180  may reconfigure (or newly adjust) a duty time with reference to a resistance value estimated based on the detect pulse DP. Based on a resistance value monitored in real time, the controller  180  may compute a duty time using the determinant of  FIG. 5  to compensate for the power coupling in the heater array  121 . The computed duty time may be updated in the duty time table  182 . 
     In operation S 150 , the controller  180  may provide the power pulse DP corresponding to the updated duty time to the heater array  121 . The controller  180  may provide the power pulse PP by controlling the row switch  151  and the column switch  153  of the heater array  121  based on the updated duty time D(r,c). In addition, the controller  180  may apply the detect pulse DP to estimate a real-time resistance value or a real-time temperature of each resistor. 
     In operation S 160 , the controller  180  may determine whether to end a temperature control operation of the electrostatic chuck system  100 . For example, the controller may determine whether a semiconductor manufacturing process performed on the wafer  101  is completed or whether a manager requests to interrupt a manufacturing process. If the semiconductor manufacturing process is not completed (No), the procedure proceeds to operation S 130 . If the semiconductor manufacturing process is completed or the manager requests to interrupt a manufacturing process (Yes), the temperature control operation of the electrostatic chuck system  100  ends. 
     In accordance with one embodiment, electrostatic chuck  110  that includes the chiller  140  and a dual-structure heater of the micro heater  120  and the macro heater  130  is controlled. In one case, due to the characteristics of the electrostatic chuck  110  at high temperatures and high pressures, it may difficult to control the target temperature of each area in real time because of a resistance change of each resistor, even though a finely computed power pulse is applied to the heater array  121 . However, according to an embodiment, the detect pulse DP for estimating a real-time resistance value of each resistor is provided to the heater array  121  after the power pulse PP is applied to the heater array  121 . A real-time resistance change of each resistor may be computed through the detect pulse DP, and a duty time of the power pulse PP may be updated by using the computation result. 
       FIG. 9  illustrates an embodiment of operation S 120  in  FIG. 8 . Referring to  FIG. 9 , the power pulse PP for heating a resistor and the detect pulse DP for estimating a real-time resistance value may be applied in units of rows. 
     In operation S 122 , one of the row switches SW_A, SW_B, SW_C, and SW_D of the micro heater  120  is turned on to select one row of the micro heater  120 . The column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  may be sequentially turned on according to a duty time corresponding to the default value D(r,c). 
     In operation S 124 , the detect pulse DP for estimating a real-time resistance value of each resistor corresponding to the selected row is applied to the heater array  121 . The detect pulse DP may be applied to the heater array  121  by simultaneously turning on the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  while one of the row switches SW_A, SW_B, SW_C, and SW_D is turned on. In this case, the controller  180  may measure and store a value of a current flowing through each resistor in the selected row based on the detect pulse DP. 
     In operation S 126 , the controller  180  determines whether a row, to which the power pulse PP and the detect pulse DP are applied, is the last row of the heater array  121 . If the row, to which the power pulse PP and the detect pulse DP are applied, is the last row of the heater array  121  (Yes), operation S 120  may end. If the row, to which the power pulse PP and the detect pulse DP are applied, is not the last row of the heater array  121  (No), the procedure proceeds to operation S 128 . 
     In operation S 128 , the controller  180  changes a row of the heater array  121 . For example, the controller  180  may change the location of a row switch to be turned on, e.g., another row may be selected. In operation S 122 , a row switch corresponding to the changed location may be turned on, and the power pulse PP may be applied to the selected row while the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are sequentially turned on. In operation S 124 , the detect pulse DP may be applied to the heater array  121  while the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  are simultaneously turned on. In one embodiment, the detailed procedure of operation S 120  may be equally applied to operation S 150 . 
       FIG. 10  illustrates another embodiment of a method for driving the micro heater  120 . Referring to  FIG. 10 , the electrostatic chuck system  100  may monitor a temperature of each area of the heater array  121  in real time without using a temperature sensor. The electrostatic chuck system  100  may again set the duty time of the power pulse PP to be applied through a switch based on the temperature monitored in real time. 
     In operation S 210 , heating may be performed by the macro heater  130  under control of the controller  180  (e.g., refer to  FIG. 1 ). In addition, a refrigerant for cooling may be supplied to the chiller  140 . 
     In operation S 220 , the controller  180  may control the micro driver  150  to apply the power pulse PP for heating the micro heater  120 . The controller  180  may control the micro driver  150  so that the power pulse PP provided to the micro heater  120  has a duty time of the default value D(r,c). The duty time D(r,c) corresponding to the default value may correspond to a value determined in a process of manufacturing the electrostatic chuck system  100 . After applying the power pulse PP for heating resistors, the controller  180  may apply the detect pulse DP to estimate a real-time temperature of each resistor. 
     In operation S 230 , the controller  180  computes a change in a resistance value of each resistor due to the detect pulse DP. To this end, the controller  180  may compute a current resistance value of each resistor with reference to a current value sampled from each resistor through the detect pulse DP. The controller  180  computes the difference between a current resistance value and a previous resistance value of each resistor. The previous resistance value of each resistor may be a default resistance value or may be a resistance value detected by using the previous detect pulse DP. 
     In operation S 240 , the controller  180  estimates the temperature of an area corresponding to each resistor based on the changed resistance value of each resistor. The temperature of each resistor may be estimated based on a relationship between a temperature and a resistance value of a resistor material. For example, a temperature variation caused by resistance value changes may be computed. In one embodiment, the controller  180  may estimate the current temperature of each resistor by multiplying a rate of temperature change (° C./Ω) to a change in a resistance value with a variation (e.g., 0.02Ω) in a resistance value of any one resistor. To estimate the temperature of each resistor, a material characteristic parameter, such as the rate of temperature change (° C./Ω) to a change in a resistance value, may be provided to the controller  180 . 
     In operation S 250 , the controller  180  may perform a parameter adjusting operation to adjust the temperature of the electrostatic chuck  110  based on the current temperature of each resistor. Based on the detected current temperature, the controller  180  may newly compute the duty time of the power pulse PP for driving the micro heater  120 . In one embodiment, the controller  180  may generate a temperature compensation value for specific areas of the electrostatic chuck  110  by changing a parameter setting of at least one of the micro heater  120 , the macro heater  130 , or the chiller  140 . 
     In operation S 260 , the controller  180  may drive at least one of the micro heater  120 , the macro heater  130 , or the chiller  140  based on a parameter set for temperature compensation. 
     In operation S 270 , the controller  180  may determine whether a manufacturing process of the electrostatic chuck system  100  is completed or whether a request to interrupt a process exists. When the manufacturing process of the electrostatic chuck system  100  is not completed or the request to interrupt a process does not exist (No), the procedure returns to operation S 230 . When the manufacturing process of the electrostatic chuck system  100  is completed or the request to interrupt a process exists, the temperature adjusting operation of the electrostatic chuck system  100  ends. 
       FIG. 11  illustrates a combination of the micro heater  120  and the micro driver  150  according to another embodiment. Referring to  FIG. 11 , the combination includes a heater array  121 ′ with resistors arranged in rows and columns, a row switch  151  to select the rows, a column switch  153  to select the columns, an a voltage source  155 . 
     In this example embodiment, the heater array  121 ′ in  FIG. 11  includes 9 resistors R 0  to R 8  arranged in a 3-by-3 matrix. Each of the resistors R 0  to R 8  of the heater array  121 ′ may not include a semiconductor rectifying device, e.g., a diode. The row switch  151 , the column switch  153 , and the voltage source  155  are configured to select the resistors R 0  to R 8  in the 3-by-3 matrix. The heater array  121 ′ may be the same as the heater array  121  in  FIG. 3 , except for the number of resistors. 
       FIG. 12  illustrates a determinant of a duty time of a power pulse for controlling the micro heater  120  having a structure of  FIG. 11 . This determinant corresponds to a duty time of the power pulse PP to be provided to the heater array  121 ′ (having 9 resistors R 0  to R 8  arranged in a 3-by-3 matrix). The determinant of  FIG. 12  corresponds to the case that the resistors R 0  to R 8  have the same resistance value. However, the determinant may be used even in the case where the resistors R 0  to R 8  have different resistance values. 
     Referring to  FIG. 12 , duty times D(a, 1 ), D(a, 2 ), D(a, 3 ), D(b, 1 ), D(b, 2 ), D(b, 3 ), D(c, 1 ), D(c, 2 ), and D(c, 3 ) corresponding to turn-on times of the column switch  153  are expressed with a function of the whole power P ON  and electric powers P(a, 1 ), P(a, 2 ), P(a, 3 ), P(b, 1 ), P(b, 2 ), P(b, 3 ), P(c, 1 ), P(c, 2 ), and P(c, 3 ) for respective resistors. In the case where the resistors R 0  to R 8  have the same resistance value, the determinant of  FIG. 12  may be calculated, for example, based on the following equations. When the resistors R 0  to R 8  have different resistance values, the determinant of  FIG. 12  may be determined with a final convergence value through an iterative operation. 
     K 1  and K 2  may be defined by Equations 2 and 3, respectively, in which “n” indicates the number of rows or columns. 
     
       
         
           
             
               
                 
                   
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       FIG. 13  illustrates a micro heater  120 ″ according to another embodiment. The micro heater  120 ″ may be expanded to have a more subdivided control structure. 
     Referring to  FIG. 13 , the micro heater  120 ″ may be managed as independent heater arrays with respect to concentric circles  127  and  128 . For example, the micro heater  120 ″ may independently control resistors between the concentric circles  127  and  128  and resistors inside concentric circle  127  and outside concentric circle  128 . This structure makes it easy to control temperature in connection with the macro heater  130 . Also, this structure may be suitable even when a temperature control unit of the micro heater  120 ″ is subdivided to a greater extent. In the micro heater  120 ″ in  FIG. 13 , locations of resistors are determined according to a geometric structure of the concentric circles  127  and  128 . In another embodiment, the resistors may be randomly arranged irrespective of a geometric structure of the micro heater  120 ″. 
       FIG. 14  illustrates an embodiment of two independent heater arrays of the micro heater  120 ″ having a structure of  FIG. 13 . Referring to  FIG. 14 , the micro heater  120 ″ may be managed in a state where the micro heater  120 ″ is divided into a first heater array  121   a  and a second heater array  121   b . In order to manage the temperature of the micro heater  120 ″ more finely, the micro heater  120 ″ may include more resistors. In order to manage more resistors, the micro heater  120 ″ may be divided into multiple arrays. Each of the first heater array  121   a  and the second heater array  121   b  may correspond to the heater array  121  of  FIG. 3 , which includes four rows and four columns. Accordingly, the first heater array  121   a  and the second heater array  121   b  may be respectively controlled based on the above-described duty time computing method taking the power coupling into consideration. 
     In one embodiment, the first heater array  121   a  and the second heater array  121   b  may be controlled independently of each other. For example, applying the power pulse PP and the detect pulse DP to the first heater array  121   a  may be independent of applying the power pulse PP and the detect pulse DP to the second heater array  121   b . The division of the micro heater  120 ″ into arrays may be performed in consideration of influence of the macro heater  130 . Based on influence of the macro heater  130  having heater electrodes in a concentric direction, the first heater array  121   a  and the second heater array  121   b  may be driven at different levels of voltages or different power sources. 
     A 4-by-4 heater array structure and a 3-by-3 heater array structure are exemplified in the aforementioned embodiments. The number of resistors of a heater array, which are arranged in rows and columns, may be different in another embodiment. A duty time matrix, to which the power coupling of the heater array is applied, may be deducted through a matrix operation using a computer. 
     In addition, a method for heating a heater array and a method for monitoring a real-time resistance change or a real-time temperature change may not be limited to driving electrostatic chuck system  100 . In other embodiments, these methods may be applied to other equipment for managing temperature with high accuracy by dividing a specific plane into a plurality of areas. 
       FIGS. 15 and 16  illustrate additional embodiments of a method for arranging resistors of the micro heater  120 ″. Referring to  FIGS. 15 and 16 , resistors of micro heater  120   a  may be arranged independently of the geometric structure of the resistor array. Even though resistors of the micro heater  120   a  are controlled by switches in an array, the resistors of the micro heater  120   a  may be arranged in concentric circle. For example, locations of resistors selected by the row switch  151  and the column switch  153  may be arranged in a concentric direction in various manners. For example, resistors  1   a ,  2   a ,  3   a , and  4   a  selected through the row switch SW_A and the column switches SW_ 1 , SW_ 2 , SW_ 3 , and SW_ 4  may be arranged in some of top-left concentric circles of the micro heater  120   a . The arrangement of the resistors may be mapped on the micro heater  120   a  in various forms, for example, according to an intended application. 
     The methods, processes, and/or operations described herein may be performed by code or instructions to be executed by a computer, processor, controller, or other signal processing device. The computer, processor, controller, or other signal processing device may be those described herein or one in addition to the elements described herein. Because the algorithms that form the basis of the methods (or operations of the computer, processor, controller, or other signal processing device) are described in detail, the code or instructions for implementing the operations of the method embodiments may transform the computer, processor, controller, or other signal processing device into a special-purpose processor for performing the methods herein. 
     The controllers, estimators, calculators, drivers, and other processing features of the disclosed embodiments may be implemented in logic which, for example, may include hardware, software, or both. When implemented at least partially in hardware, the controllers, estimators, calculators, drivers, and other processing features may be, for example, any one of a variety of integrated circuits including but not limited to an application-specific integrated circuit, a field-programmable gate array, a combination of logic gates, a system-on-chip, a microprocessor, or another type of processing or control circuit. 
     When implemented in at least partially in software, the controllers, estimators, calculators, drivers, and other processing features may include, for example, a memory or other storage device for storing code or instructions to be executed, for example, by a computer, processor, microprocessor, controller, or other signal processing device. The computer, processor, microprocessor, controller, or other signal processing device may be those described herein or one in addition to the elements described herein. Because the algorithms that form the basis of the methods (or operations of the computer, processor, microprocessor, controller, or other signal processing device) are described in detail, the code or instructions for implementing the operations of the method embodiments may transform the computer, processor, controller, or other signal processing device into a special-purpose processor for performing the methods herein. 
     In accordance with one or more of the aforementioned embodiments, an electrostatic chuck system includes a heater array having a matrix structure for finely adjusting the temperature of a target area or a target point without using a semiconductor device. In addition, the electrostatic chuck system may control the temperature and electric power in real time based on a result of detecting a characteristic change of a resistor varying in real time. 
     Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.