Patent Publication Number: US-2021175055-A1

Title: Measuring device, measuring method, and vacuum processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Japanese Patent Application No. 2019-221379, filed on Dec. 6, 2019, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a measuring device, a measuring method, and a vacuum processing apparatus. 
     BACKGROUND 
     Conventionally, there is known a vacuum processing apparatus for performing various treatments for processing a substrate such as a semiconductor wafer (hereinafter, referred to as “wafer”) disposed in a processing chamber maintained in a vacuum state. In the vacuum processing apparatus, it is important to measure a state in the processing chamber, such as an emission intensity of plasma, because the state in the processing chamber affects the characteristics of the substrate after the processing. 
     Therefore, there is suggested a technique measuring the emission intensity of plasma in the processing chamber from the outside of the processing chamber using an optical emission spectrometer (OES) disposed on a sidewall of the processing chamber through a quartz window (see, e.g., Japanese Patent Application Publication No. 2018-107264). 
     SUMMARY 
     The present disclosure provides a technique capable of measuring the state in the processing chamber with high accuracy without opening the processing chamber to the atmosphere. 
     In accordance with an aspect of the present disclosure, there is provided a measuring device for a vacuum processing apparatus including a processing chamber having a first gate for loading and unloading a substrate and a second gate different from the first gate, the measuring device including: a case having an opening that is sized to correspond to the second gate of the processing chamber and is airtightly attachable to the second gate; a decompressing mechanism configured to reduce a pressure in the case; and a measuring mechanism accommodated in the case and configured to measure a state in the processing chamber through the opening in a state where the pressure in the case is reduced by the decompressing mechanism. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects and features of the present disclosure will become apparent from the following description of embodiments, given in conjunction with the accompanying drawings, in which: 
         FIG. 1  schematically shows a plasma etching apparatus according to an embodiment; 
         FIG. 2  is a cross-sectional view schematically showing a measuring device according to the embodiment; 
         FIG. 3  is a flowchart showing an example of a sequence of measuring a state in a processing chamber using the measuring device according to the embodiment; and 
         FIGS. 4 to 12  explain a specific example of the sequence of measuring the state in the processing chamber using the measuring device according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Like reference numerals will be given to like or corresponding parts throughout the drawings. 
     In the case of measuring a state in a processing chamber from the outside of the processing chamber using a measuring device such as an optical emission spectrometer (OES), the measuring device is distant from a substrate disposed in the processing chamber and, thus, the measurement accuracy near the substrate is diminished. 
     Therefore, in a vacuum processing apparatus, it is considered to open the processing chamber to the atmosphere and dispose the measuring device such as an OES near the substrate to directly measure the state in the processing chamber. However, in the vacuum processing apparatus, once the processing chamber is opened to the atmosphere, a considerable amount of time is required to restart the substrate processing due to a control such as temperature adjustment or moisture control in the processing chamber. As a result, the productivity is lowered. 
     In addition, it is considered to measure the state in the processing chamber without opening the processing chamber to the atmosphere by providing the measuring device such as an OES at a transfer system such as a transfer arm for transferring a substrate to a vacuum, processing apparatus maintained in the vacuum state and transferring the measuring device into the processing chamber using the transfer system. Since, however, the measuring device is heavier than the substrate, the transfer system having a strength that can withstand the weight of the measuring device is required in the case of transferring the measuring device using the transfer system. Therefore, it is not practical to transfer the measuring device using the transfer system. 
     Hence, it is desired to measure the state in the processing chamber with high accuracy without opening the processing chamber to the atmosphere. 
     Configuration of the Measurement Target Device 
     Hereinafter, a measurement target device to be measured by the measuring device will be described. The measurement target device is a vacuum processing apparatus for performing predetermined substrate processing on a substrate such as a wafer disposed in a processing chamber maintained in a vacuum state. In the present embodiment, a case where the measurement target device is a plasma etching apparatus for performing plasma etching on the substrate will be described as an example. 
       FIG. 1  schematically shows a plasma etching apparatus according to an embodiment. A. plasma etching apparatus  10  includes an airtight processing chamber  30  that is electrically grounded. The processing chamber  30  has a cylindrical shape and is made of, e.g., aluminum having an anodically oxidized surface. The processing chamber  30  defines a processing space in which plasma is generated. A substrate support  31  for horizontally supporting the wafer W is disposed in the processing chamber  30 . 
     The substrate support  31  has a substantially cylindrical shape with an upper surface and a bottom surface oriented in a vertical direction. The upper surface of the substrate support  31  serves as a substrate supporting surface  36   d.  The substrate supporting surface  36   d  of the substrate support  31  is greater in size than the wafer W. The substrate support includes a base  33  and an electrostatic chuck  36 . 
     The base  33  is made of a conductive metal such as aluminum. The base  33  serves as a lower electrode. The base  33  is supported by an insulating support  34  disposed at a bottom portion of the processing chamber  30 . 
     The electrostatic chuck  36  has a flat disc-shaped upper surface. The upper surface serves as the substrate supporting surface  36   d  on which the wafer W is placed. The electrostatic chuck  36  is disposed at the center of the substrate support  31  in plan view. The electrostatic chuck  36  has an electrode  36   a  and an insulator  36   b.  The electrode  36   a  is embedded in the insulator  36   b.  A DC power supply  42  is connected to the electrode  36   a.  The electrostatic chuck  36  is configured to attract and hold the wafer W by a Coulomb force generated by applying a DC voltage from the DC power supply  42  to the electrode  36   a.  Further, a heater  36   c  is disposed in the insulator  36   b  of the electrostatic chuck  36 . The heater  36   c  controls the temperature of the wafer W by a power supplied through a power supply mechanism to be described later. 
     A focus ring  35  made of, e.g., single crystalline silicon, is disposed on an outer peripheral portion of the substrate support  31 . Further, a cylindrical inner wall member  37  made of, e.g., quartz, is disposed to surround the substrate support  31  and the support  34 . 
     A power feed rod  50  is connected to the base  33 . A first radio frequency (RF) power supply  40   a  is connected to the power feed rod  50  through a first matching unit  41   a,  and a second RF power supply  40   b  is connected to the power feed rod  50  through a second matching unit  41   b.  The first RF power supply  40   a  is a power supply for plasma generation. An RF power having a predetermined frequency is supplied from the first RF power supply  40   a  to the base  33  of the substrate support  31 . Further, the second RF power supply  40   b  is a power supply for ion attraction (for bias). An RF power having a predetermined frequency lower than that of the first RF power supply  40   a  is supplied from the second RF power supply to the base  33  of the substrate support  31 . 
     A coolant channel  33   d  is formed in the base  33 . The coolant channel  33   d  has one end connected to a coolant inlet line  33   b  and the other end connected to a coolant outlet line  33   c.  The plasma etching apparatus  10  is configured to control the temperature of the substrate support  31  by supplying and circulating a coolant such as cooling water through the coolant channel.  33   d.  Further, the plasma etching apparatus  10  may have a configuration in which the temperature of the wafer W and the temperature of the focus ring  35  can be individually controlled by separately providing coolant channels in the areas of the base  33  that correspond to the areas where the wafer W and the focus ring  35  are placed. Moreover, the plasma etching apparatus  10  may have a configuration in which the temperature of the wafer W and the temperature of the focus ring  35  can be individually controlled by supplying a cold heat transfer gas to a backside of the wafer W or to a bottom surface of the focus ring  35 . For example, a gas supply line for supplying the cold heat transfer gas (backside gas) such as helium gas to the backside of the wafer W may be formed through the substrate support  31 . The gas supply line is connected to a pas supply source. With this configuration, the wafer W attracted and held by the electrostatic chuck  36  on the upper surface of the substrate support  31  is controlled to a predetermined temperature. 
     A shower head  46  serving as an upper electrode is disposed above the substrate support  31  to face the substrate support  31  in parallel therewith. The shower head  46  and the substrate support  31  function as a pair of electrodes (upper electrode and lower electrode). 
     The shower head  46  is disposed at a ceiling wall portion of the processing chamber  30 . The shower head  46  includes a main body  46   a  and an upper ceiling plate  46   b  serving as an electrode plate. The shower head  46  is supported at an upper portion of the processing chamber  30  through an insulating member  47 . The main body  46   a  is made of a conductive material, e.g., aluminum having an anodically oxidized surface. The upper ceiling plate  46   b  is detachably held at a bottom surface of the main body  46   a.    
     A gas diffusion space  46   c  is formed in the main body  46   a.  A plurality of gas holes  46   d  is formed in a bottom portion of the main body  46   a  to be positioned under the gas diffusion space  46   c.  Gas injection holes  46   e  are formed through the upper ceiling plate  46   b  in a thickness direction thereof to communicate with the gas holes  46   d,  respectively. With such a configuration, a processing gas supplied to the gas diffusion space  46   c  is diffused and supplied in a shower-like manner into the processing chamber  30  through the gas holes  46   d  and the gas injection holes  46   e.    
     A gas inlet port  46   g  for introducing the processing gas into the gas diffusion space  46   c  is formed in the main body  46   a.  One end of a gas supply line  45   a  is connected to the gas inlet port  46   g.  The other end of the gas supply line  45   a  is connected to a processing gas supply source  45  for supplying the processing gas. A mass flow controller (MFC)  45   b  and an opening/closing valve V 2  are disposed in the gas supply line  45   a,  in that order, from an upstream side. The processing gas for plasma etching is supplied from the processing gas supply source  45  to the gas diffusion space  46   c  through the gas supply line  45   a,  and then is diffused and supplied in a shower-like manner into the processing chamber  30  through the gas holes  46   d  and the gas injection holes  46   e.    
     A variable DC power supply  48   b  electrically connected to the shower head  46  serving as the upper electrode through a low pass filter (LPF)  48   a.  The variable DC power supply  48   b  can be on-off controlled by an on/off switch  48   c.  A current and a voltage of the variable DC power supply  48   b  and on/off operation of the on/off switch  48   c  are controlled by a controller  90  to be described later. As will be described later, when plasma is generated in the processing space by applying the RF power from the first RF power supply  40   a  and the RF power from the second RF power supply  40   b  to the substrate support  31 , the on/off switch  48   c  is turned on by the controller  90  and a predetermined DC voltage is applied to the shower head  46  serving as the upper electrode, if necessary. 
     A cylindrical ground conductor  30   a  extends upward from a sidewall of the processing chamber  30  to a position higher than a height of the shower head  46 . The cylindrical ground conductor  30   a  has a ceiling wall at the top thereof. 
     A gas exhaust port  81  is formed at the bottom portion of the processing chamber  30 . A gas exhaust unit  83  is connected to the gas exhaust port  81  through a gas exhaust line  82 . The gas exhaust unit  83  may include a vacuum pump. By operating the vacuum pump, a pressure in the processing chamber  30  can be decreased to a predetermined vacuum level. 
     A first gate  84  for loading and unloading the wafer W is provided at the sidewall of the processing chamber  30 . A gate valve G for opening and closing the first gate  84  is provided at the first gate  84 . The first gate  84  is connected to a vacuum transfer chamber through the gate valve G while maintaining airtightness and the wafer P can be loaded into and unloaded from the vacuum transfer chamber while maintaining the vacuum atmosphere. 
     A deposition shield  86  is provided along an inner wall surface of the processing chamber  30 . The deposition shield prevents etching by-products (deposits) from being attached to the processing chamber  30 . The deposition shield  86  is detachably provided. 
     The operation of the plasma etching apparatus  10  configured as described above is integrally controlled by the controller  90 . The controller  90  is, e.g., a computer and controls the individual components of the plasma etching apparatus  10 . 
     In the plasma etching apparatus  10 , it is important to measure a state in the processing chamber  30  because the state in the processing chamber  30  affects the characteristics of the processed wafer W. Therefore, there is suggested a technique for measuring an emission intensity of plasma in the processing chamber  30  from the outside of the processing chamber using an optical emission spectrometer (OES) disposed on the sidewall of the processing chamber  30  through a quartz window. 
     However, in the case of measuring the state in the processing chamber  30  from the outside of the processing chamber  30  using the measuring device such as the OES, the measuring device is distant from the wafer W disposed in the processing chamber and, thus, the measurement accuracy near the substrate is diminished. 
     Therefore, in the plasma etching apparatus  10 , it is considered to open the processing chamber to the atmosphere and dispose the measuring device such as an OES near the substrate to directly measure the state in the processing chamber. However, in the plasma etching apparatus  10 , once the processing chamber  30  is opened to the atmosphere, a considerable amount of time is required to restart the substrate processing due to a control such as temperature adjustment or moisture control in the processing chamber  30 . Thus, the productivity is lowered. 
     In view of the above, it is considered to measure the state in the processing chamber  30  without opening the processing chamber  30  to the atmosphere by providing the measuring device such as an OES at a transfer system such as a transfer arm for transferring the wafer W to the plasma etching apparatus  10  and transferring the measuring device into the processing chamber  30  using the transfer system. Since, however, the measuring device is heavier than the wafer W, the transfer system having a strength that can withstand the weight of the measuring device is required in the case of transferring the measuring device using the transfer system. Therefore, it is not practical to transfer the measuring device using the transfer system. 
     Therefore, the plasma etching apparatus  10  according to the embodiment further includes a gate for measuring the state in the processing chamber  30  in addition to the first gate  84  for loading and unloading the wafer W. For example, as shown in  FIG. 1 , the plasma etching apparatus  10  includes a second gate  95  on a side opposite to the side where the first gate  84  is disposed with respect to the substrate support  31  on which the wafer W is placed. The second gate  95  is airtightly closed by a lid  96 . A measuring device  100  to be described later is detachably attached to the second gate  95 . In the case of measuring the state in the processing chamber  30 , an operator attaches the measuring device  100  to the plasma etching apparatus  10  that is a target apparatus to be measured by the measuring device  100 . 
     Configuration of the Measuring Device 
     Next, the configuration of the measuring device  100  according to the embodiment will be described.  FIG. 2  is a cross-sectional view schematically showing the measuring device  100  according to the embodiment.  FIG. 2  shows a state in which the measuring device  100  is attached to the plasma etching apparatus  10 . In the following drawings, the plasma etching apparatus  10  is illustrated in a simplified manner. 
     The measuring device  100  includes a case  101  having an opening  101 A that is sized to correspond to the second gate  95  of the plasma etching apparatus  10 . An O-ring  101 O is disposed at a portion around the opening  101 A where the case  101  is in contact with the plasma etching apparatus  10 . Further, the case  101  is mounted on a transfer vehicle  102 . The measuring device  100  is transferred to the position of the plasma etching apparatus  10  by the transfer vehicle  102 , and the opening  101 A of the case  101  is positioned to correspond to the second gate  95 . Then, the opening  101 A of the case  101  is airtightly attached and fixed to the second gate  95  by means of screws, for example. 
     The case  101  includes a first case  101 B and a second case  101 C communicating with the first case  101 B through an openable shutter member  101 D. A measuring mechanism to be described later is accommodated in the first case  101 B. The opening  101 A is formed in the second case  101 C. 
     A first pipe  104 A provided with a first valve  105 A is connected to the first case  101 B. A second pipe  104 B provided with a second valve  105 B is connected to the second case  101 C. The first pipe  104 A and the second pipe  104 B are connected to a vacuum pump  106  through a common pipe  104 C. The vacuum pump  106  is placed on a loading platform  103  disposed in the transfer vehicle  102 . The second pipe  104 B is branched into a leakage pipe  104 D between the second case  101 C and the second valve  105 B. The leakage pipe  104 D is provided with a leakage valve  105 C. The vacuum pump  106 , the first pipe  104 A, the second pipe  104 B, and the common pipe  104 C constitute a decompressing mechanism for reducing a pressure in the case  101 . When the state in the processing chamber  30  is measured, the measuring device  100  operates the vacuum pump  106  to perform evacuation through the first pipe  104 A, the second pipe  104 B, and the common pipe  104 C to reduce a pressure in the first case  101 B and a pressure in the second case  101 C. 
     The measuring mechanism configured to measure the state in the processing chamber  30  is disposed in the first case  101 B. The measuring device  100  of the present embodiment includes, as the measuring mechanism, a robot arm  110  and a sensor  111  disposed at a tip end of the robot arm  110 . The sensor  111  is configured to measure the state in the processing chamber  30 . 
     The robot arm  110  includes an arm unit in which multiple arms are indirectly connected and a support unit for supporting the arm unit to be rotatable and vertically movable. The robot arm  110  is configured to be extensible and contractible by unfolding the arms of the arm unit in a straight line or folding the arms. The robot arm  110  can extend the multiple arms of the arm unit toward the opening  101 A so that the tip end thereof can enter the processing chamber  30  through the opening  101 A. The operation of the robot arm  110  is integrally controlled by a control unit (not shown). The control unit includes a user interface that receives various operation instructions or displays the operation status. An operator sends an operation instruction to the user interface. For example, the operation instruction individually specifies the movements of the robot arm  110 . Alternatively, the operation instruction may specify a series of movements. For example, the operation instruction may specify a series of movements for measuring The state in the processing chamber  30  using the sensor  111 . 
     Further, the robot arm  110  is detachably attached to the first case  101 B. In other words, the robot arm  110  can be replaced by a different robot arm having a sensor different from the sensor  111  at the tip end thereof. 
     Further, the robot arm  110  has a lid  112  in the middle of the arm unit. When the lid  96  is removed from the second gate  95 , the lid  112  airtightly closes the second gate  95 , instead of the lid  96 . 
     The sensor  111  is transferred by the robot arm  110  to a predetermined position in the processing chamber  30  through the opening  101 A and measures the state in the processing chamber  30  at the predetermined position. For example, the sensor  111  is transferred to a position above the wafer hi placed on the substrate support  31  and measures the state in the processing chamber  30  at the position above the wafer W. The state in the processing chamber  30  that can be measured by the sensor  111  include, e.g., an electron density of plasma generated in the processing chamber  30 , a frequency of the RF power applied for plasma generation, a mass of ions in the plasma, a pressure in the processing chamber  30 , a temperature and a surface shape of the wafer W, and the like. Further, when the sensor  111  is transferred by the robot arm  110  to a position above the focus ring  35  around the wafer W, the sensor  111  may measure the consumption amount of the focus ring  3  or the position of the focus ring  35 . The sensor  111  may integrally measure multiple different states, or may individually measure multiple states. The data indicating the state measured by the sensor  111  may be stored in a predetermined storage device in the measuring device  100 , or may be transmitted to a communication device that can communicate with the measuring device  100  in a wired/wireless manner. The communication device may be, e.g., the plasma etching apparatus  10 , or another plasma etching apparatus different from the plasma etching apparatus  10 . 
     Further, the measuring device  100  includes a removing unit for removing the lid  96  from the second gate  95  of the plasma etching apparatus  10 . For example, the measuring device  100  includes, as the removing unit, a robot arm  120  and a robot hand  121  provided at a tip end of the robot arm  120 . The robot arm  120  has an arm unit in which multiple arms are indirectly connected and a support unit supporting the arm unit to be rotatable and vertically movable. The robot arm  120  can extend the multiple arms of the arm unit toward the lid  96 , grip the lid  96  with the robot hand  121 , and remove the lid  96  from the second gate  95 . The movements of the robot arm  120  and the robot hand  121  are integrally controlled by a control unit (not shown). The control unit includes a user interface that receives various operation instructions and displays the operation status. An operator sends an operation instruction to the user interface. For example, the operation instruction individually specifies the movements of the robot arm  120  or the movements of the robot hand  121 . Alternatively, the operation instruction may specify a series of movements. For example, the operation instruction may specify a series of movements for removing the lid  96  from the second gate  95 . 
     Next, an example of a measurement using the measuring device  100  will be described.  FIG. 3  is a flowchart showing an example of a sequence of measuring the state in the processing chamber  30  using the measuring device  100  according to the embodiment. 
     First, the opening  101 A of the case  101  is airtightly attached to the second gate  95  (step S 101 ). Next, the measuring device  100  operates the vacuum pump  106  to reduce the pressure in the case  101  (step S 102 ). Next, the measuring device  100  measures the state in the processing chamber  30  through the opening  101 A using the measuring mechanism (the robot arm  110  and the sensor  111 ) in a state where the pressure in the case  101  as reduced (step S 103 ). 
     Next, a specific example of the measurement using the measuring device  100  will be described.  FIGS. 4 to 12  explain the specific example of the sequence of measuring the state in the processing chamber  30  using the measuring device  100  according to the embodiment. 
     When the state in the processing chamber  30  is measured, an operator moves the transfer vehicle  102  to transfer the measuring device  100  to the position of the plasma etching apparatus  10  as shown in  FIG. 4 . At this time, the first valve  105 A is controlled to be open. Then, the vacuum pump  106  reduces the pressure in the first case  101 B in a state where the shutter member  101 D is closed. 
     Next, as shown in  FIG. 5 , the opening  101 A of the case  101  (the second case  101 C) is airtightly attached to the second gate  95 . The process of  FIG. 5  corresponds to step S 101  of  FIG. 3 . 
     When the opening  101 A of the case  101  (the second case  101 C) is attached to the second gate  95 , the first valve  105 A is switched from the open state to the closed state, and the second valve  105 B is controlled to be open as shown in  FIG. 6 . Then, the vacuum pump  106  reduces the pressure in the second case  101 C. Accordingly, both of the pressure in the first case  101 B and the pressure in the second case  101 C, i.e., the pressure in the entire case  101  is reduced. The process of  FIG. 6  corresponds to step S 102  of  FIG. 3 . 
     Next, as shown in  FIG. 7 , the shutter member  101 D is open, and the first case  101 B and the second case  101 C communicate with each other. Then, the second valve  105 B is switched from the open state to the closed state. 
     Next, as shown in  FIG. 8 , the robot arm  120  extends the multiple arms of the arm unit toward the lid  96 , grips the lid  96  with the robot hand  121 , and removes the lid  96  from the second gate  95 . Accordingly, the second gate  95  is open, and the case  101  and the processing chamber  30  communicate with each other. Then, the robot arm  120  retracts the lid  96  to a predetermined retreat position in the second case  101 C. 
     Next, as shown in  FIG. 9 , the robot arm  110  extends the multiple arms of the arm unit toward the opening  101 A so that the tip end of the robot arm  110  where the sensor  111  is disposed enters the processing chamber  30  through the opening  101 A. Therefore, the sensor  111  is transferred to a predetermined position in the processing chamber  30  through the opening  101 A. Further, the robot arm  110  airtightly attaches the lid  112  provided at the arm unit to the second gate  95 . Accordingly, the second gate  95  is airtightly closed by the lid  112 . When the lid  112  is attached to the second gate  95 , the plasma etching apparatus  10  generates plasma in the processing chamber  30 . Then, the sensor  111  measures the state in the processing chamber  30  at the predetermined position in the processing chamber  30 . For example, the sensor  111  measures the state in the processing chamber  30  at a position above the wafer W placed on the substrate support  31 . Further, the robot arm  110  may sequentially move the tip end provided with the sensor  111  to multiple positions in the processing chamber  30 . Accordingly, the sensor  111  is sequentially transferred to the multiple positions in the processing chamber  30 . Then, the sensor  111  measures the state in the processing chamber  30  at each of the positions. For example, the sensor  111  measures the state in the processing chamber  30  at a position above the central portion of the wafer W placed on the substrate support  31 , and then measures the state in the processing chamber  30  at a position above the edge portion of the wafer W. The process of  FIG. 9  corresponds to seep S 103  of  FIG. 3 . 
     When the measurement of the sensor  111  is completed, the plasma etching apparatus  10  stops the generation of plasma in the processing chamber  30 . When the generation of plasma in the processing chamber  30  is stopped, the robot arm  110  contracts the multiple arms of the arm unit so that the tip end provided with the sensor  111  retracts into the case  101  (the first case  101 B) as shown in  FIG. 10 . At this time, the robot arm  110  removes the lid  112  from the second gate  95 . 
     Next, as shown in  FIG. 11 , the robot arm  120  extends the multiple arms of the arm unit toward the predetermined retreat position in the second case  101 C, grips the lid  96  with the robot hand  121 , and attaches the lid  96  to the Gate  95 . Accordingly, the second gate  95  is airtightly closed by the lid  96 . 
     Next, as shown in  FIG. 12 , the second case  101 C is opened to the atmosphere by opening the leakage valve  105 C in a state where the shutter member  101 D is closed. After the state in the processing chamber  30  is measured in the above-described order, the operator moves the transfer vehicle  102  to separate the measuring device  100  from the plasma etching apparatus  10 . 
     As described above, the measuring device  100  of the present embodiment includes the case  101  that is airtightly attached to the second gate  95  and has the opening  101 A that is sized to correspond to the second gate  95  of the plasma etching apparatus  10 . The measuring device  100  further includes the decompressing mechanism for reducing a pressure in the case  101 . The measuring device  100  further includes the measuring mechanism that is accommodated in the case  101  to measure the state in the processing chamber  30  through the opening  101 A in a state where the pressure in the case  101  is reduced by the decompressing mechanism. Accordingly, the measuring device  100  can measure the state in the processing chamber  30  with high accuracy without opening the processing chamber  30  to the atmosphere. Further, since the measuring device  100  measures the state in the processing chamber  30  without using the transfer system for transferring the wafer W, the transfer of the measuring device by using the transfer system can be omitted. As a result, the strength required for the transfer system can be reduced. 
     Further, the measuring mechanism of the measuring device  100  of the present embodiment further includes the robot arm  110  whose tip end can enter the processing chamber  30  through the opening  101 A and the sensor  111  disposed at the tip end of the robot arm  110  to measure a state in the processing chamber  30 . Accordingly, the measuring device  100  can directly measure the state in the processing chamber  30  at any position in the processing chamber  30  without exposing the processing chamber  30  to the atmosphere. 
     Further, the robot arm  110  of the present embodiment is detachably attached to the case  101  (the first case  101 B). Thus, the measuring device  100  can easily replace the robot arm  110  with a different robot arm having another sensor. Accordingly, various states in the processing chamber  30  can be measured using various sensors. 
     When the opening  101 A of the second case  101 C is not attached to the second gate  95 , the decompressing mechanism of the measuring device  100  of the present embodiment reduces the pressure in the first case  101 B in a state where the shutter member  101 D is closed. When the opening  101 A of the second case  101 C is attached to the second gate  95 , the decompressing mechanism reduces the pressure in the second case  101 C. In a state where the pressure in the first case  101 B and the pressure in the second case  101 C are reduced, after the shutter member  101 D and the second gate  95  are open, the robot arm  110  moves the tip end thereof provided with the sensor  111  into the processing chamber  30  through the opening  101 A. Therefore, the measuring device  100  can use the second case  101 C as a vacuum preliminary chamber. Accordingly, it is possible to prevent particles or moisture in the atmosphere from entering the first case  101 B or the processing chamber  30 . 
     Further, the plasma etching apparatus  10  of the present embodiment further includes the processing chamber  30  having the first gate  84  for loading and unloading the wafer W and the second gate  95  to which the measuring device  100  configured to measure the state in the processing chamber  30  is detachably attached. Accordingly, the plasma etching apparatus  10  can measure the state in the processing chamber  30  with high accuracy without opening the processing chamber  30  to the atmosphere. Since the plasma etching apparatus  10  measures the state in the processing chamber  30  without using the transfer system for transferring the wafer W, the transfer of the measuring device by using the transfer system can omitted. Hence, the strength required for the transfer system can be reduced. 
     The presently disclosed embodiments are considered in all respects to be illustrative and not restrictive. The above-described embodiments can be embodied in various forms. Further, the above-described embodiments may be omitted, replaced, or changed in various forms without departing from the scope of the appended claims and the gist thereof. 
     For example, in the above-described embodiment, the case where the measuring device  100  is used for measuring the state in the processing chamber  30  of the plasma etching apparatus  10  has been described as an example. However, the present disclosure is not limited thereto. The measurement target device to be measured by the measuring device  100  may be any apparatus as long as it includes a processing chamber in a vacuum state. 
     Further, in the above-described embodiment, the case where the second gate  95  of the plasma etching apparatus  10  is closed by the lid  96  while maintaining airtightness has been described as an example. However, the present disclosure is not limited thereto. For example, a gate valve G may be disposed at the second gate  95  of the plasma etching apparatus  10  to open and close the second gate  95 . In this case, the measuring device  100  does not require the removing unit (e.g., the robot arm  120  and the robot hand  121 ) for removing the lid  96  from the second gate  95 . 
     Further, in the above-described embodiment, the case where the state in the processing chamber  30  is measured using the sensor  111  disposed at the tip end of the robot arm  110  has been described as an example. However, the present disclosure is not limited thereto. For example, the measuring device  100  may directly measure the state in the processing chamber  30  using a sensing wafer that is placed on the substrate support  31  by the robot arm and has the same sensing function as that of the sensor  111 . 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures.