Patent Publication Number: US-2021175093-A1

Title: Substrate processing apparatus and substrate processing method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Japanese Patent Application No. 2019-219842 filed on Dec. 4, 2019, the entire disclosure of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The various aspects and embodiments described herein pertain generally to a substrate processing apparatus and a substrate processing method. 
     BACKGROUND 
     Patent Document 1 describes a technique of etching titanium nitride without corroding a wiring material used in a semiconductor substrate.
     Patent Document 1: Japanese Patent Laid-open Publication No. 2008-285508   

     SUMMARY 
     In one exemplary embodiment, a substrate processing apparatus includes a temperature detector, a calculation unit and an execution unit. The temperature detector is configured to detect a temperature of a substrate on which a processing liquid is discharged. The calculation unit is configured to calculate, by using a given calculation formula, an etching amount of the substrate based on the temperature detected by the temperature detector. The execution unit configured to perform an etching processing on the substrate by the processing liquid based on the etching amount. 
     The foregoing summary is illustrative only and is not intended to be any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the detailed description that follows, embodiments are described as illustrations only since various changes and modifications will become apparent to those skilled in the art from the following detailed description. The use of the same reference numbers in different figures indicates similar or identical items. 
         FIG. 1  is a diagram illustrating a schematic configuration of a substrate processing system according to an exemplary embodiment; 
         FIG. 2  is a schematic diagram illustrating a specific configuration example of a processing unit according to the exemplary embodiment; 
         FIG. 3  is a schematic diagram illustrating a pipeline configuration of the substrate processing system according to the exemplary embodiment; 
         FIG. 4  is a block diagram illustrating a schematic configuration of a control device according to the exemplary embodiment; 
         FIG. 5  is a diagram illustrating an exponential curve according to the exemplary embodiment; 
         FIG. 6  is a flowchart illustrating a control processing according to the exemplary embodiment; 
         FIG. 7A  is a first diagram showing a wafer temperature and an etching amount in the control processing according to the exemplary embodiment; 
         FIG. 7B  is a second diagram showing the wafer temperature and the etching amount in the control processing according to the exemplary embodiment; and 
         FIG. 7C  is a third diagram showing the wafer temperature and the etching amount in the control processing according to the exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings, which form a part of the description. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. Furthermore, unless otherwise noted, the description of each successive drawing may reference features from one or more of the previous drawings to provide clearer context and a more substantive explanation of the current exemplary embodiment. Still, the exemplary embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings, may be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein. 
     Hereinafter, exemplary embodiments of a substrate processing apparatus and a substrate processing method according to the present disclosure will be described in detail with reference to the accompanying drawings. The substrate processing apparatus and the substrate processing method of the present disclosure are not limited to the exemplary embodiments to be described below. Further, it should be noted that the drawings are schematic and relations in sizes of individual components and ratios of the individual components may sometimes be different from actual values. Even between the drawings, there may exist parts having different dimensional relationships or different ratios. 
     &lt;Outline of Substrate Processing System&gt; 
       FIG. 1  is a diagram illustrating a schematic configuration of a substrate processing system  1  (an example of a substrate processing apparatus) according to an exemplary embodiment. In the following, in order to clarify positional relationships, the X-axis, Y-axis and Z-axis which are orthogonal to each other will be defined, and the positive Z-axis direction will be regarded as a vertically upward direction. 
     The substrate processing system  1  includes a carry-in/out station  2  and a processing station  3 . The carry-in/out station  2  and the processing station  3  are provided adjacent to each other. The substrate processing system  1  is configured to perform an etching processing on a semiconductor wafer W (hereinafter, simply referred to as “wafer W”). 
     Films formed on the wafer W (an example of a substrate) on which the etching processing is to be performed are titanium nitride and tungsten. Further, a processing liquid for the etching processing is dilute sulfuric acid prepared by diluting sulfuric acid with pure water, for example, DIW (DeIonized Water). The dilute sulfuric acid has a predetermined concentration in which a ratio between the sulfuric acid and the pure water ranges from 1:1 to 20:1. Further, the processing liquid may be SPM (an aqueous solution of sulfuric acid and hydrogen peroxide). 
     The carry-in/out station  2  is provided with a carrier placing section  11  and a transfer section  12 . In the carrier placing section  11 , a plurality of carriers C is placed to accommodate a plurality of substrates (semiconductor wafers W (hereinafter, referred to as “wafers W”) in the present exemplary embodiment) horizontally. 
     The transfer section  12  is provided adjacent to the carrier placing section  11 , and provided with a substrate transfer device  13  and a delivery unit  14 . The substrate transfer device  13  is provided with a wafer holding mechanism configured to hold the wafer W. Further, the substrate transfer device  13  is movable horizontally and vertically and pivotable around a vertical axis, and transfers the wafers W between the carriers C and the delivery unit  14  by using the wafer holding mechanism. 
     The processing station  3  is provided adjacent to the transfer section  12 . The processing station  3  is provided with a transfer section  15  and a plurality of processing units  16 . The processing units  16  are arranged at both sides of the transfer section  15   
     The transfer section  15  is provided with a substrate transfer device  17  therein. The substrate transfer device  17  is provided with a wafer holding mechanism configured to hold the wafer W. Further, the substrate transfer device  17  is movable horizontally and vertically and pivotable around a vertical axis. The substrate transfer device  17  transfers the wafers W between the delivery unit  14  and the processing units  16  by using the wafer holding mechanism. 
     The processing units  16  perform a predetermined substrate processing on the wafers W transferred by the substrate transfer device  17 . 
     Further, the substrate processing system  1  is provided with a control device  4 . The control device  4  is, for example, a computer, and includes a controller  18  and a storage  19 . The storage  19  stores a program that controls various processings performed in the substrate processing system  1 . The controller  18  controls the operations of the substrate processing system  1  by reading and executing the program stored in the storage  19 . Details of the control device  4  will be elaborated later. 
     Further, the program may be recorded in a computer-readable recording medium, and installed from the recording medium to the storage  19  of the control device  4 . The computer-readable recording medium may be, for example, a hard disc (HD), a flexible disc (FD), a compact disc (CD), a magneto optical disc (MO), or a memory card. 
     In the substrate processing system  1  configured as described above, the substrate transfer device  13  of the carry-in/out station  2  first takes out a wafer W from a carrier C placed in the carrier placing section  11 , and then places the taken wafer W on the delivery unit  14 . The wafer W placed on the delivery unit  14  is taken out from the delivery unit  14  by the substrate transfer device  17  of the processing station  3  and carried into a processing unit  16 . 
     The wafer W carried into the processing unit  16  is processed by the processing unit  16 , and then, carried out from the processing unit  16  and placed on the delivery unit  14  by the substrate transfer device  17 . After the processing of placing the wafer W on the delivery unit  14 , the wafer W returns to the carrier C of the carrier placing section  11  by the substrate transfer device  13 . 
     &lt;Configuration of Processing Unit&gt; 
     Now, a configuration of the processing unit  16  will be described with reference to  FIG. 2 .  FIG. 2  is a schematic diagram illustrating a specific configuration example of the processing unit  16  according to the exemplary embodiment. As depicted in  FIG. 2 , the processing unit  16  includes a chamber  20 , a substrate processing unit  30 , a liquid supply  40 , a recovery cup  50 , and a temperature sensor  60 . 
     The chamber  20  accommodates therein the substrate processing unit  30 , the liquid supply  40 , and the recovery cup  50 . A FFU (Fan Filter Unit)  21  is provided at a ceiling of the chamber  20 . The FFU  21  creates a downflow within the chamber  20 . 
     The substrate processing unit  30  is equipped with a holder  31 , a supporting column  32 , and a driver  33 , and configured to perform a liquid processing on the wafer W placed thereon. The holder  31  is configured to hold the wafer W horizontally. The supporting column  32  is a vertically extending member. A base end of the supporting column  32  is rotatably supported by the driver  33 , and the supporting column  32  supports the holder  31  horizontally at a leading end thereof. The driver  33  is configured to rotate the supporting column  32  around a vertical axis. 
     In the substrate processing unit  30 , by rotating the supporting column  32  with the driver  33 , the holder  31  supported by the supporting column  32  is rotated, so that the wafer W held by the holder  31  is rotated. 
     A holding member  311  configured to hold the wafer W from the lateral side thereof is provided at a top surface of the holder  31  of the substrate processing unit  30 . The wafer W is horizontally held by this holding member  311  while being slightly spaced apart from the top surface of the holder  31 . Further, the wafer W is held by the holder  31  with a front surface thereof to be subjected to a substrate processing facing upwards. 
     The liquid supply  40  is configured to supply a processing liquid onto the wafer W. The liquid supply  40  is equipped with a nozzle  41 , an arm  42  configured to support the nozzle  41  horizontally, and a rotating/elevating mechanism  43  configured to rotate and move the arm  42  up and down. 
     The nozzle  41  is connected to a discharge line  130 . The nozzle  41  is configured to discharge the processing liquid supplied through the discharge line  130 . A pipeline configuration of the substrate processing system  1  including this discharge line  130  will be elaborated later. 
     Further, though the present exemplary is described for an example where the single nozzle  41  is provided in the processing unit  16 , the number of the nozzle provided in the processing unit  16  is not limited to one. Further, though the present exemplary is described for an example where the nozzle  41  is disposed above (at a side of a front surface of) the wafer W in the processing unit  16 , the nozzle may be disposed under (at a side of a rear surface of) the wafer W. 
     The recovery cup  50  is disposed to surround the holder  31 , and collects the processing liquid scattered from the wafer W by the rotation of the holder  31 . A drain port  51  is formed at a bottom of the recovery cup  50 , and the processing liquid collected by the recovery cup  50  is drained from the drain port  51  to the outside of the processing unit  16 . Further, an exhaust port  52  is formed at the bottom of the recovery cup  50  to exhaust a gas supplied from the FFU  21  to the outside of the processing unit  16 . 
     The temperature sensor  60  (an example of a temperature detector) is configured to detect a temperature of the wafer W (an example of a substrate) onto which the processing liquid is discharged. To elaborate, the temperature sensor  60  is configured to measure a surface temperature of the wafer W. The temperature sensor  60  may be, by way of example, but not imitation, a radiation thermometer. The temperature sensor  60  is mounted to the chamber  20  with a mounting member  61  therebetween. The temperature sensor  60  measures a temperature of a preset position of the wafer W. The preset position is a previously set position and may be, for example, a center of the wafer W. The temperature sensor  60  may be fixed to the arm  42 . Further, the temperature sensor  60  may be fixed to an arm different from the arm  42 . 
     &lt;Pipeline Configuration of Substrate Processing System&gt; 
     Now, a pipeline configuration of the substrate processing system  1  connected to the processing unit  16  will be explained with reference to  FIG. 3 .  FIG. 3  is a schematic diagram illustrating the pipeline configuration of the substrate processing system  1  according to the exemplary embodiment. 
     Here, the pipeline configuration for supplying the processing liquid will be explained. Besides this pipeline system for the processing liquid, the processing unit  16  is equipped with, by way of example, a pipeline configuration and a nozzle for supplying DIW onto the wafer W in a rinsing processing and a pipeline configuration and a nozzle for supplying IPA onto the wafer W in a drying processing. 
     In the substrate processing system  1 , dilute sulfuric acid produced by a joint unit  120  is supplied into the processing unit  16  through the discharge line  130 . Sulfuric acid from a chemical liquid supply  100  and DIW from a DIW supply  110  are supplied into the joint unit  120 . In the joint unit  120 , the sulfuric acid and the DIW are mixed, so that the dilute sulfuric acid is produced. 
     The chemical liquid supply  100  is configured to supply the sulfuric acid to the joint unit  120 . The chemical liquid supply  100  is equipped with a chemical liquid source  101 , a supply line  102 , a heater  103 , and a flow rate controller  104 . The sulfuric acid supplied into the supply line  102  from the chemical liquid source  101  is heated by a heater  103  to a first preset temperature. A flow rate of the sulfuric acid heated to the first preset temperature is adjusted by the flow rate controller  104 . The first preset temperature is a previously set temperature which allows a temperature of the processing liquid to become equal to or higher than 50° C., and is set to be equal to or lower than a boiling point of the processing liquid. 
     The DIW supply  110  is configured to supply the DIW to the joint unit  120 . The DIW supply  110  is equipped with a DIW source  111 , a supply line  112 , a heater  113 , and a flow rate controller  114 . The DIW supplied into the supply line  112  from the DIW source  111  is heated by a heater  113  to a second preset temperature. A flow rate of the DIW heated to the second preset temperature is adjusted by the flow rate controller  114 . The second preset temperature is a previously set temperature which allows the temperature of the processing liquid to become equal to or higher than 50° C., and is set to be equal to or lower than the boiling point of the processing liquid. 
     In the substrate processing system  1 , by using the flow rate controllers  104  and  114 , a concentration of the processing liquid produced in the joint unit  120  is adjusted to a preset concentration. The discharge line  130  is provided with a valve  131 . If the valve  131  is opened, the processing liquid adjusted to have the preset concentration is supplied to the wafer W. If the valve  131  is closed, the processing liquid is not supplied to the wafer W. The valve  131  is opened/closed by a motor (not shown) or the like. 
     Further, in the substrate processing system  1 , by stopping the flow of the sulfuric acid in the flow rate controller  104  provided in the supply line  102 , the DIW may be supplied to the wafer W via the discharge line  130 . 
     &lt;Details of Control Device&gt; 
     Now, details of the control device  4  which controls the substrate processing system  1  will be explained with reference to  FIG. 4 .  FIG. 4  is a block diagram illustrating a schematic configuration of the control device  4  according to the exemplary embodiment. As stated above, the control device  4  includes the controller  18  and the storage  19 . 
     The storage  19  may be configured by, for example, a semiconductor memory device such as a RAM (Random Access Memory) or a flash memory, or a storage device such as a hard disk or an optical disk. The storage  19  has a calculation formula storage  19   a.    
     The calculation formula storage  19   a  stores s calculation formula for calculating an etching amount D in an etching processing. The etching amount D can be calculated from a processing time (t 1 −t 0 ) in the etching processing and an etching rate k by using the expression (1). 
         D=k ×( t 1− t 0)  (1)
 
     Here, “t 1 ” denotes a supply time of the processing liquid, and “t 0 ” represents a time when the wafer W reaches a target temperature at which the etching is begun. That is, the processing time is a time after the wafer W reaches the target temperature. The target temperature is equal to or higher than 50° C. and equal to or lower than the boiling point of the processing liquid. 
     Further, the etching rate k can be calculated, by using the expression (2), from an average wafer temperature Tave after the wafer W reaches the target temperature. 
         k=a ×exp( b×T ave)  (2)
 
     If “k” of the expression (2) is put in the place of “k” of the expression (1), the following expression (3) is obtained. 
         D =( a ×exp( b×T ave))×( t 1− t 0)  (3)
 
     Here, “a” and “b” are exponential approximation fitting values. Further, “a” and “b” are calculated by using actual preliminary evaluation data. The preliminary evaluation data refers to data in which an etching processing is performed while varying a temperature of sulfuric acid and a concentration of sulfuric acid and a wafer temperature and an etching amount D′ are obtained under respective conditions. 
     Further, a wafer W used to obtain the preliminary evaluation data is the same as the wafer W on which the etching processing is performed in the substrate processing system  1 . A measurement point of the temperatures of the wafer W in the preliminary evaluation data is the same as the measurement point of the temperatures detected by the temperature sensor  60  when the etching processing is performed in the substrate processing system  1 . 
     First, a time average wafer temperature Tave′ in each condition is calculated from the etching processing time and the temperature of the wafer W. Further, an etching rate k′ in each condition is obtained from the etching processing time and the etching amount D′. 
     Then, a graph in which the time average wafer temperature Tave′ in each condition and the etching rate k′ in each condition are plotted is created as shown in  FIG. 5 , and is approximated by an exponential curve.  FIG. 5  is a diagram showing an exponential curve according to the exemplary embodiment. The aforementioned “a” and “b” are calculated and set based on the approximated exponential curve. 
     As stated above, the calculation formula of the expression (3) (an example of a given calculation formula) is a formula of an exponential function of the temperature of the wafer W and the processing time in the etching processing. The calculation formula storage  19   a  stores the calculation formula represented by the expression (3). Further, the calculation formula storage  19   a  stores the calculation formula for each etching processing condition, for example, the calculation formula according to the kind of the wafer W on which the etching processing is performed. 
     Referring back to  FIG. 4 , the controller  18  may be implemented by a CPU (Central Processing Unit) or MPU (Micro Processing Unit) or the like which executes the various programs stored in the storage  19  by using a RAM as a working area. Further, the controller  18  may be implemented by an integrated circuit such as, but not limited to, ASIC (Application Specific Integrated Circuit) or a FPGA (Field Programmable Gate Array). 
     The controller  18  includes an acquisition unit  18   a , a calculation unit  18   b , a determination unit  18   c  and an execution unit  18   d , and implements or carries out a function and an operation of a control processing to be described below. Further, the internal configuration of the controller  18  is not limited to the example shown in  FIG. 4 , and the controller  18  may have various other configurations as long as it is capable of carrying out the following control processing. 
     The acquisition unit  18   a  is configured to acquire the information regarding the temperature of the wafer W (hereinafter, referred to as “wafer temperature”) detected by the temperature sensor  60 . The calculation unit  18   b  is configured to calculate the etching amount D from the acquired wafer temperature by using the calculation formula stored in the calculation formula storage  19   a . That is, by using the calculation formula (an example of a given calculation formula), the calculation unit  18   b  calculates the etching amount D of the wafer W (an example of a substrate) based on the wafer temperature (an example of a temperature) detected by the temperature sensor  60  (an example of a temperature detector). 
     The determination unit  18   c  is configured to determine whether or not to end the etching processing. To elaborate, the determination unit  18   c  makes a determination upon whether the calculated etching amount D has reached a preset amount. The preset amount is a previously set value, and is an etching amount required for the wafer W. 
     The execution unit  18   d  is configured to perform the etching processing upon the wafer W (an example of the substrate) by the processing liquid based on the etching amount D. The execution unit  18   d  controls the supply of the processing liquid upon the wafer W, thus allowing the etching processing to be performed on the wafer W. The execution unit  18   d  controls a motor or the like, and performs the opening/closing of the valve  131 . 
     To elaborate, to start the etching processing, the execution unit  18   d  opens the valve  131 , thus beginning the supply of the processing liquid onto the wafer W. Further, if it is determined that the etching amount D has reached the preset amount, the execution unit  18   d  closes the valve  131 , stopping the supply of the processing liquid upon the wafer W. That is, if the etching amount D reaches the preset amount (given amount), the execution unit  18   d  ends the discharge of the processing liquid. 
     Here, the function of the control device  4  of performing the discharge control of the processing liquid in the etching processing has been described. However, the control device  4  also performs, besides this discharge control, sulfuric acid temperature adjustment by the heater  103  and DIW temperature adjustment by the heater  113 . Furthermore, the control device  4  performs a rinsing processing and a drying processing as well as the etching processing. 
     As stated above, the control device  4  calculates the etching amount D based on the wafer temperature by using the calculation formula, and ends the etching processing if the etching amount D reaches the preset amount. Thus, even if there is caused non-uniformity during the etching due to a non-uniform wafer temperature, the etching amount D can be made to reach the preset amount. 
     &lt;Specific Example of Control Processing&gt; 
     Now, a control processing according to the exemplary embodiment will be explained with reference to  FIG. 6 .  FIG. 6  is a flowchart illustrating the control processing according to the exemplary embodiment. 
     The control device  4  begins the etching processing (S 100 ). To elaborate, the control device  4  opens the valve  131 , thus allowing the processing liquid to be supplied to the wafer W. 
     The control device  4  calculates the etching amount D (S 101 ). To elaborate, the control device  4  acquires the wafer temperature from the temperature sensor  60 , and calculates the etching amount D based on the acquired wafer temperature by using the calculation formula. 
     The control device  4  determines whether the calculated etching amount D has reached the preset amount (S 102 ). If the etching amount D has reached the preset amount (S 102 : Yes), the control device  4  ends the etching processing (S 103 ). Specifically, the control device  4  closes the valve  131 , thus stopping the discharge of the processing liquid onto the wafer W. 
     If the calculated etching amount D is smaller than the preset amount (S 102 : No), the control device  4  carries on the calculation of the etching amount D (S 101 ). 
     Now, the wafer temperature and the etching amount D in the above-stated control processing will be described with reference to  FIG. 7A  to  FIG. 7C .  FIG. 7A  is a first diagram showing the wafer temperature and the etching amount D in the control processing according to the exemplary embodiment.  FIG. 7B  is a second diagram showing the wafer temperature and the etching amount D in the control processing according to the exemplary embodiment.  FIG. 7C  is a third diagram showing the wafer temperature and the etching amount D in the control processing according to the exemplary embodiment. 
     If the supply of the processing liquid upon the wafer W is begun ( FIG. 7A ), the temperature of the wafer W increases. If the temperature of the wafer W becomes equal to or higher than a target temperature at a time t 0 , the etching upon the wafer W by the processing liquid is begun, so that the etching amount D increases. Further, the etching amount D is calculated based on the aforementioned expression (3). 
     As the supply of the processing liquid upon the wafer W is continued and the temperature of the wafer W is maintained equal to or higher than the target temperature, the etching progresses, so that the etching amount D increases ( FIG. 7B ). 
     If the calculated etching amount D reaches the preset amount ( FIG. 7C ), the supply of the processing liquid upon the wafer W is stopped. Then, the temperature of the wafer W falls below the target temperature, so that the etching upon the wafer W is ended. 
     Effects 
     The substrate processing system  1  (an example of a substrate processing apparatus) includes the temperature sensor  60  (an example of a temperature detector), the calculation unit  18   b  and the execution unit  18   d . The temperature sensor  60  detects the temperature of the wafer W (an example of a substrate) onto which the processing liquid is discharged. The calculation unit  18   d  calculates, by using the calculation formula (given calculation formula), the etching amount D of the wafer W based on the temperature detected by the temperature sensor  60 . The execution unit  18   d  performs the etching processing upon the wafer W by the processing liquid based on the etching amount D. 
     Accordingly, the substrate processing system  1  is capable of calculating the etching amount D based on the temperature of the wafer W and carrying out the etching processing based on the etching amount D. The substrate processing system  1  performs the etching processing based on the etching amount D even if the temperature of the processing liquid varies due to a minute change in the supply flow rate of the sulfuric acid or the DIW. Therefore, the substrate processing system  1  is capable of etching the wafer W accurately. 
     Further, the execution unit  18   d  ends the supply of the processing liquid if the etching amount D reaches the preset value (an example of a given value). 
     Accordingly, the substrate processing system  1  is capable of allowing the etching amount D to reach the preset amount even if the non-uniformity is caused during the etching due to the non-uniform wafer temperature. Therefore, the substrate processing system  1  is capable of etching the wafer W accurately. 
     Furthermore, the calculation formula is a formula of the exponential function of the temperature and the processing time in the etching processing. 
     Thus, the substrate processing system  1  is capable of calculating the etching amount D accurately, and thus capable of etching the wafer W with high accuracy. 
     Further, the temperature sensor  60  detects the surface temperature of the wafer W. 
     Accordingly, the substrate processing system  1  is capable of calculating the etching amount D based on the temperature of the wafer W on which the etching processing is performed. Thus, the substrate processing apparatus  1  is capable of etching the wafer W accurately. 
     Further, the films formed on the wafer W on which the etching processing is performed are titanium nitride and tungsten. 
     The substrate processing system  1  is capable of accurately etching the wafer W on which the films of the titanium nitride and the tungsten are formed. 
     Further, the processing liquid is the dilute sulfuric acid prepared by diluting the sulfuric acid with the DIW (an example of pure water). Specifically, the processing liquid has the concentration in which the ratio between the sulfuric acid and the pure water ranges from 1:1 to 20:1. Further, the processing liquid has the temperature equal to or higher than 50° C. and equal to or lower than the boiling point of the processing liquid. 
     Accordingly, the substrate processing system  1  is capable of etching the titanium nitride while suppressing etching of the tungsten. 
     MODIFICATION EXAMPLES 
     The substrate processing system  1  may calculate the etching amount D by using a formula of an exponential function different from the calculation formula of the exponential function represented by the expression (3). The formula of the exponential function is calculated from a correlation between the temperature of the wafer W and the etching amount D′ by using the preliminary evaluation data. By way of example, the substrate processing system  1  may calculate the etching amount D by using an Arrhenius equation represented by the following expression (4). 
         K/A =exp(− E/RT )  (4)
 
     “K” denotes a rate constant, and “A” is a frequency factor. Further, “E” indicates an activation energy; “R”, a gas constant; “T”, a temperature of the wafer W. 
     The etching amount D is proportional to a section integration of the processing time of “K/A”. Thus, the etching amount D can be calculated by using the following expression (5). 
         D=a×J ( K/A ) dt   (5)
 
     If the expression (4) is put in the expression (5), the etching amount D can be represented by the following expression (6). 
         D=a×J (exp(− E/RT )) dt   (6)
 
     Proportionality constants “a” and “E” are calculated and set by using the preliminary evaluation data. Specifically, based on the preliminary evaluation data, “a” is calculated from a gradient of an approximation straight line in a graph on which (J(exp(−E/RT))dt) is plotted as a horizontal axis and the etching amount D′ is plotted as a vertical axis. Further, a value of “E” is varied, and the value allowing the highest coefficient of determination is calculated as “E”. The calculation formula of the expression (5) is stored in the calculation formula storage  19   a.    
     The substrate processing system  1  may calculate the etching amount D by using the expression (5) stored in the calculation formula storage  19   a.    
     Accordingly, the substrate processing system  1  is capable of etching the wafer W with high accuracy. 
     Further, the method of measuring the temperature of the wafer W is not limited to using the temperature sensor  60  as described above. By way of example, in the substrate processing system  1 , a temperature sensor such as a thermocouple may be provided at a contact portion in contact with the wafer W. 
     Furthermore, the substrate processing system  1  may measure temperatures of the wafer W at multiple positions. By way of example, the substrate processing system  1  may measure a temperature of a central portion of the wafer W, a temperature of a peripheral portion of the wafer W, and a temperature of a portion between the central portion and the peripheral portion of the wafer W. In this case, for example, calculation formulas set for the temperatures of the wafer W at the multiple positions are stored in the calculation formula storage  19   a . By way of example, the substrate processing system  1  calculates etching amounts D at the multiple positions of the wafer W and performs the etching processing based on the etching amounts D. Furthermore, the substrate processing system  1  may correct an etching amount D by estimating a difference between the multiple etching amounts D. 
     In addition, the substrate processing system  1  may supply the processing liquid onto the wafer W while rotating the arm  42 . Further, the substrate processing system  1  may measure multiple temperatures of the wafer W by supplying the processing liquid onto the wafer W while rotating the arm  42 . 
     Accordingly, the substrate processing system  1  is capable of etching the wafer W accurately. The substrate processing system  1  is capable of improving the uniformity of the etching amount D within the surface of the wafer W. 
     Moreover, based on the etching amount D, the substrate processing system  1  may calculate a time taken before the etching processing is finished, and may end the etching processing based on the calculated time. 
     The features of the substrate processing system  1  according to the exemplary embodiment and the modification examples may be applied in combinations. 
     So far, the exemplary embodiments have been described. However, it should be noted that the above-described exemplary embodiments are illustrative in all aspects and are not anyway limiting. The above-described exemplary embodiments may be omitted, replaced and modified in various ways without departing from the scope and the spirit of claims 
     According to the present disclosure, it is possible to etch the substrate with high accuracy. 
     From the foregoing, it will be appreciated that the various embodiments of the present disclosure have been described herein for the purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the following claims.