Abstract:
There is provided a pressure measuring device including: a first pressure gauge connected to a processing chamber configured to process a process target and configured to measure an internal pressure of the processing chamber when the process target is being processed; a second pressure gauge connected to the processing chamber; and a first switching valve configured to disconnect the second pressure gauge from the processing chamber when the process target is being processed inside the processing chamber.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of Japanese Patent Application No. 2016-055220, filed on Mar. 18, 2016, in the Japan Patent Office, the disclosure of which is incorporated herein in its entirety by reference. 
       TECHNICAL FIELD 
       [0002]    The present disclosure relates to a pressure measuring device and an exhaust system using the same, and a substrate processing apparatus. 
       BACKGROUND 
       [0003]    A substrate processing apparatus having a configuration in which pressure measuring parts are installed corresponding to the number of types of gases supplied into a processing chamber is known in the conventional art. The processing chamber receives substrates such that each substrate is dedicated to the respective gases, and a film is not formed on a diaphragm sensor that constitutes each of the pressure measuring parts so as not cause an error in measured pressure values. 
         [0004]    In addition, a pressure measuring device is know in the art in which a circular plate is installed at a position facing a diaphragm to form an annular flow path, and a solid substance adheres to a place at which the diaphragm is less affected by stress, so that the effect of the stress occurred by the adhered solid substance on a deformation of the diaphragm is reduced. 
         [0005]    However, such configurations, although possible to reduce the occurrence of an error in a pressure gauge, fail to accurately recognize the error of the pressure gauge. To address this requires periodically checking a shifted amount of the pressure gauge and periodically performing a zero-adjustment by which the pressure gauge is reset to zero in a state where a processing chamber is exhausted up to a maximum vacuum level. 
         [0006]    Such zero adjustment is an approximate-level compensation in which the pressure gauge is reset to zero when a vacuum level is maximum, namely closest to zero), rather than accurately recognizing an error or shifted amount of the pressure gauge and performing a compensation based on the recognized result. This configuration fails to accurately compensate the pressure gauge. There is another technique for connecting a high precision pressure gauge during maintenance and compensating an erroneous pressure gauge by identifying a difference between these pressure gauges. In any case, it is impossible to accurately check a replacement time of the erroneous pressure gauge. Thus, only an ex-post measure that the erroneous pressure gauge is initially replaced when some problems occur, were possible. 
       SUMMARY 
       [0007]    Some embodiments of the present disclosure provide a pressure measuring device which is capable of accurately recognizing an error of a pressure gauge and precisely compensating the error based on the recognized result, and an exhaust system using the same, and a substrate processing apparatus. 
         [0008]    According to one embodiment of the present disclosure, there is provided a pressure measuring device including: a first pressure gauge connected to a processing chamber configured to process a process target and configured to measure an internal pressure of the processing chamber when the process target is being processed; a second pressure gauge connected to the processing chamber; and a first switching valve configured to disconnect the second pressure gauge from the processing chamber when the process target is being processed inside the processing chamber. 
         [0009]    According to another embodiment of the present disclosure, there is provided an exhaust system including: the aforementioned pressure measuring device; an exhaust part connected to the processing chamber through a conduit; and a pressure adjustment valve installed in the conduit and configured to adjust the internal pressure of the processing chamber, which is to be exhausted by the exhaust part, wherein the control part is configured to control a set value of the pressure adjustment valve using a shifted amount in the error of the first pressure gauge. 
         [0010]    According to yet another embodiment of the present disclosure, there is provided a substrate processing apparatus including: the aforementioned exhaust system; a processing chamber connected to the exhaust system; a substrate holding part installed inside the processing chamber and configured to hold the substrate; and a process gas supply part configured to supply a process gas into the processing chamber. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure. 
           [0012]      FIG. 1  is an overall configuration view showing an example of a pressure measuring device, an exhaust system using the same and a substrate processing apparatus, according to an embodiment of the present disclosure. 
           [0013]      FIG. 2  is a view showing a pressure measuring device, an exhaust system, and a substrate processing apparatus according to a comparative example. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Hereinafter, an embodiment of the present disclosure will be described with respect to the drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments. 
         [0015]      FIG. 1  is an overall configuration view showing an example of a pressure measuring device and an exhaust system using the same, and a substrate processing apparatus, according to an embodiment of the present disclosure 
         [0016]    The pressure measuring device according to an embodiment of the present disclosure includes pressure gauges  80  and  81 , switching valves  90  and  91 , a controller  100 , and conduits  51  to  53 . 
         [0017]    In addition, the exhaust system according to the present embodiment includes conduits  50  and  54  to  56 , a vacuum pump  60 , a pressure adjustment valve  70 , and switching valves  92  and  93 , in addition to the above-described pressure measuring device. 
         [0018]    Further, the substrate processing apparatus according to the present embodiment includes a processing chamber  10 , a substrate holding table  20 , a process gas supply part  30 , and a process gas supply source  40 , in addition to the above-mentioned exhaust system. 
         [0019]    In  FIG. 1 , the processing chamber  10  is coupled to the vacuum pump  60  through the conduit  50 . The pressure adjustment valve  70  is installed in the conduit  50  between the processing chamber  10  and the vacuum pump  60 . In addition, the processing chamber  10  and the pressure gauges  80  and  81  are connected with each other through the conduits  51  to  53 . The pressure gauge  80  is coupled to the common conduit  51  through the conduit  52 . The pressure gauge  81  is coupled to the common conduit  51  through the conduit  53 . In addition, the switching valve  91  is installed in the conduit  53 . In addition, the conduit  54  is connected to the conduit  51 , and is coupled to the conduit  50  through the conduit  56 . The switching valve  92  is installed in the conduit  54 . Furthermore, the conduit  55  is connected to the conduit  50 , and is joined with the conduit  54  in the conduit  56  connected to the conduit  50 . The switching valve  93  is installed in the conduit  55 . 
         [0020]    The processing chamber  10  is to perform a predetermined process with respect to a process target received therein. The process target may be a variety of objects that require a process or treatment. However, in the present embodiment, an example in which the pressure measuring device and the exhaust system are applied to the substrate processing apparatus configured to process a substrate, specifically a wafer W, will be described. However, the pressure measuring device according to the present embodiment may be applied to a variety of devices inclusive of a processing equipment as long as they are required to perform a pressure measurement under process. Further, the exhaust system may be applied to a variety of apparatuses that require an exhaust process. In addition, the substrate processing apparatus may be applied to a variety of substrate processing apparatuses such as a film forming apparatus, an etching apparatus or an annealing apparatus as long as they include an exhaust system and are configured to process a substrate. Hereinafter, a description will be made as to an example in which the substrate processing apparatus is configured as a film forming apparatus. 
         [0021]    The substrate holding table  20  and the process gas supply part  30  are installed in the processing chamber  10 . The substrate holding table  20  is a substrate holding part for holding the wafer W (substrate) as an object to be processed. The substrate holding table  20  may be configured in the form of a table as shown in  FIG. 1 . Further, the substrate holding table  20  may be a holding part such as a wafer boat which holds a plurality of wafers W such that they are arranged to overlap each other in a vertically spaced-apart relationship when viewed from the top. The configuration of the substrate holding table  20  for holding the substrates is not particularly limited. 
         [0022]    The process gas supply part  30  is to supply a process gas for processing the wafer W held on the substrate holding table  20 . The process gas may be a process gas for forming a film on the wafer W, or a gas for etching the wafer W. When the process gas comes into contact with diaphragms of the pressure gauges  80  and  81  and when a film formation or the like is performed, an extra stress may be applied to the diaphragms. This makes it impossible to accurately measure pressure. The pressure measuring device according to the present embodiment prevents a measurement error from being generated in the pressure gauge  80  even if such a process gas is supplied to the wafer for the substrate process. 
         [0023]    The process gas supply source  40  is to supply a predetermined process gas to the process gas supply part  30 , which is adapted to the substrate process. 
         [0024]    The vacuum pump  60  is an exhaust part for evacuating the interior of the processing chamber  10 . In addition, the exhaust part is not limited to the vacuum pump  60  which performs a vacuum-exhaust operation as long as it can perform an exhaust operation. In the present embodiment, an example in which the interior of the processing chamber  10  is vacuum-exhausted using the vacuum pump  60  as the exhaust part will be described. 
         [0025]    The conduit  50  is a conduit for exhaust through which the processing chamber  10  and the vacuum pump  60  are connected to each other. The conduit  50  may be other various conduits as long as they can exhaust the interior of the processing chamber  10 . 
         [0026]    The pressure adjustment valve  70  is an adjustment part for adjusting an internal pressure of the processing chamber  10 . The pressure adjustment valve  70  adjusts the internal pressure of the processing chamber  10  by adjusting, for example, an opening degree of a valve. Specifically, as the opening degree of the valve increases, an exhaust amount of the vacuum pump  60  is increased so that the internal pressure of the processing chamber  10  is lowered. On the contrary, as the opening degree of the valve decreases, the exhaust amount of the vacuum pump  60  is decreased so that the internal pressure of the processing chamber  10  is raised. For example, the pressure adjustment valve  70  can adjust the internal pressure of the processing chamber  10  through the aforementioned operation. Thus, the internal pressure of the processing chamber  10  is set by the pressure adjustment valve  70 . 
         [0027]    In addition, the pressure adjustment valve  70  is basically designed to adjust the internal pressure of the processing chamber  10  such that a pressure to be adjusted becomes a pressure set according to a recipe. However, in the present embodiment, the controller  100  compensates the set pressure if desired. Details thereof will be described later. 
         [0028]    The pressure gauge  80  is a process pressure gauge that measures the internal pressure of the processing chamber  10  when the substrate process is being performed inside the processing chamber  10 . Therefore, when the wafer W is being processed inside the processing chamber  10 , the switching valve  90  is opened and the pressure gauge  80  is coupled to the processing chamber  10  through the conduits  51  and  52 . The conduit  51  is a common conduit through which both the pressure gauges  80  and  81  are connected to the processing chamber  10 . The switching valve  90  is installed in the conduit  51  used as the common conduit and determines whether both the pressure gauges  80  and  81  are required to be connected to the processing chamber  10 . 
         [0029]    Meanwhile, the conduit  52  is a branch conduit that is branched from the conduit  51  and is connected to only the pressure gauge  80 . A switching valve is not installed in the branch conduit  52 . Thus, if the switching valve  90  is opened, the pressure gauge  80  is automatically coupled to the processing chamber  10 , thereby measuring the internal pressure of the processing chamber  10 . Therefore, when the wafer W is being processed inside the processing chamber  10 , the switching valve  90  remains opened. 
         [0030]    The pressure gauge  81  is a compensation pressure gauge which is configured to measure the internal pressure of the processing chamber  10  when the substrate process is not being performed inside the processing chamber  10 , without having to measure the internal pressure of the processing chamber  10  when the substrate process is being performed inside the processing chamber  10 . Therefore, the pressure gauge  81  is required to be disconnected from the processing chamber  10  during the substrate process. To do this, the switching valve  91  is installed in the conduit  53 . 
         [0031]    When the wafer W is being processed inside the processing chamber  10 , the switching valve  91  remains closed such that the pressure gauge  81  is disconnected from the processing chamber  10 . Thus, even if the wafer W is being processed inside the processing chamber  10 , it is possible to keep the pressure gauge  81  in a clean state which is not exposed to the process gas used inside the processing chamber  10 . 
         [0032]    In addition, the pressure gauges  80  and  81  may have a variety of configurations. For example, the pressure gauges  80  and  81  may be configured in a generally-used diaphragm type. Such a diaphragm type pressure gauge, which has a sensitive portion configured with a diaphragm, measures a pressure by recognizing a displacement caused by bending through the use of an electrostatic capacitance or the like. If a solid substance adheres to the diaphragm due to a film formation or the like, the diaphragm may be displaced due to shrinkage of the solid substance. This shifts a zero point, thus causing an error. 
         [0033]    When the wafer W is being processed inside the processing chamber  10 , a process gas supplied into the processing chamber  10  may flow into the pressure gauge  80 . As such, the solid substance may adhere to the diaphragm of the pressure gauge  80 , which causes an error. 
         [0034]    Meanwhile, when the wafer W is being processed inside the processing chamber  10 , the switching valve  91  remains closed to disconnect the pressure gauge  81  from the processing chamber  10 . Thus, the pressure gauge  81  is kept clean. When the process of the wafer W is stopped and the adjustment by the pressure gauge  80  is performed, the switching valve  91  is opened such that both the pressure gauges  80  and  81  measure the internal pressure of the processing chamber  10 . In this case, since the process gas is not supplied into the processing chamber  10 , no process gas flows into both the pressure gauges  80  and  81  from the processing chamber  10 . Therefore, both the pressure gauges  80  and  81  can measure the internal pressure of the processing chamber  10  in a clean state. 
         [0035]    In some embodiments, in the case where the adjustment by the pressure gauge  80  is performed, the pressure measurement may be performed in a state in which the interior of the processing chamber  10  is exhausted at a maximum up to a maximum vacuum level of the vacuum pump  60 , which is a maximum ability. The reason for this is that the error in the pressure measurement in such a state is minimal. 
         [0036]    The pressure gauges  80  and  81  simultaneously measure the internal pressure of the processing chamber  10  under the same condition, which makes it possible to recognize an error (shifted amount) caused in the pressure gauge  80 . That is to say, since the pressure gauge  81  exhibits a correct pressure, a difference between the pressure gauge  80  and the pressure gauge  81  is recognized as the error of the pressure gauge  80 . 
         [0037]    As described above, the pressure gauge  81  as a compensation pressure gauge is installed which is disconnected from the processing chamber  10  during the process of the wafer W and is connected to the processing chamber  10  only when the adjustment by the pressure gauge  80  is performed. By performing the connection and the disconnection using the switching valve  91  installed in the branch conduit  53 , it is possible to accurately recognize a measurement error caused in the pressure gauge  80 . 
         [0038]    In addition, although in  FIG. 1 , both the pressure gauges  80  and  81  are coupled to the processing chamber  10  through the common conduit  51 , the present disclosure is not limited thereto. In some embodiments, the pressure gauges  80  and  81  may be separately and independently connected to the processing chamber  10 . In this case, the pressure gauges  80  and  81  may simultaneously measure the internal pressure of the processing chamber  10  under the same condition. Thus, it is possible to measure an error of the pressure gauge  80 . However, in the above configuration, an extra conduit or completely-separated conduit is required to be additionally employed. In this case, conduits installed in the pressure gauges  80  and  81  may not be connected to the conduit  51  in a common condition, which causes a slight difference in connection condition. Thus, as shown in  FIG. 1 , the pressure gauges  80  and  81  are configured to be connected to the processing chamber  10  through the common conduit  51 . 
         [0039]    The controller  100  is a control part for setting a pressure of the pressure adjustment valve  70  based on pressure values measured by the pressure gauges  80  and  81 . The controller  100  can monitor the pressure values measured by the pressure gauges  80  and  81 , and recognize the measured pressure values. Therefore, the controller  100  is able to recognize the shifted error caused in the pressure gauge  80  as a process pressure gauge, based on a difference between the measured pressure values of the pressure gauge  80  and pressure gauge  81 . 
         [0040]    The controller  100  calculates a compensation value for compensating the measurement error of the pressure gauge  80 , and sets the pressure of the pressure adjustment valve  70  using the compensation value thus calculated. For example, if an error caused in the pressure gauge  80  is +0.5 Torr, the pressure gauge  80  may output a measured pressure value higher by 0.5 Torr than the actual pressure. Therefore, in the case where a set pressure according to a recipe is 2.0 Torr, if the set pressure of the pressure adjustment valve  70  is inputted as 2.0 Torr, even though the initial pressure is controlled to be 2.0 Torr by the pressure adjustment valve  70 , the pressure gauge  80  may output a pressure of 2.5 Torr. The controller  100  performs a feedback control based on the value thus outputted and determines that the measured pressure of 2.5 Torr is higher than a target pressure of 2.0 Torr by 0.5 Torr, thus performing an adjustment for reducing the output pressure by 0.5 Torr. Therefore, the actual internal pressure of the processing chamber  10  may be controlled to be 1.5 Torr, which fails to set the pressure according to the recipe. Accordingly, in such a case, the controller  100  executes a compensation operation of setting the target pressure of the pressure adjustment valve  70  to 2.5 Torr. If the actual internal pressure of the processing chamber  10  is set to be 2.5 Torr by the pressure adjustment valve  70 , the pressure gauge  80  outputs a measured pressure of 3.0 Torr. The controller  100  performs the feedback control based on the measured pressure and determines that the measured pressure of 3.0 Torr is higher than the target pressure of 2.5 Torr by 0.5 Torr. Thus, the controller  100  controls the pressure adjustment valve  70  to perform the adjustment (control) of reducing the output pressure by 0.5 Torr. Then, the actual internal pressure of the processing chamber  10  is controlled to be 2.0 Torr, which is the set pressure according to the recipe. 
         [0041]    Even in the case where the pressure gauge  80  exhibits a negatively-shifted error, the pressure gauge  80  may be controlled in the same manner as the above. For example, if the pressure gauge  80  exhibits an error shifted by −0.5 Torr, the target pressure of the pressure adjustment valve  70  is set to be 1.5 Torr, which is lower by 0.5 Torr than the set pressure of 2.0 Torr according to recipe of 2.0 Torr. In this case, when the actual internal pressure of the processing chamber  10  is 2.0 Torr, the pressure gauge  80  outputs a measured pressure of 1.5 Torr. Therefore, it is possible to control the actual internal pressure to be 2.0 Torr. 
         [0042]    As described above, by calculating a shifted amount to be used in shift-compensating the pressure gauge  80  and setting the target pressure of the pressure adjustment valve  70  to be increased (added) based on the calculated shifted amount, it is possible to control the internal pressure of the processing chamber  10  to become the set pressure according to the recipe. In this case, the controller  100  merely shifts the target pressure of the pressure adjustment valve  70 , and then performs a general feedback control. Thus, there is no need to perform a detailed calculation process for every feedback control, which makes it possible to reduce a calculation process load. 
         [0043]    In addition, in order to execute the aforementioned calculation process, the controller  100  may be configured as, for example, a microcomputer that includes a CPU (Central Processing Unit) and memory parts such as a ROM (Read Only Memory), a RAM (Random Access Memory) and the like, and operates according to a program. Alternatively, the controller  100  may be configured as an electronic circuit such as an ASIC (Application Specific Integrated Circuit) that is an integrated circuit in which a plurality of function circuits is integrated for a specific use. As described above, the controller  100  may be configured in a variety of other forms as long as they are able to perform the aforementioned calculation process and control. 
         [0044]    In addition, information on the recipe may be recorded in, for example, a storage medium, and may be installed in the controller  100  from the storage medium. 
         [0045]    The conduit  54  constitutes a portion of a bypass line for directly connecting the processing chamber  10  and the vacuum pump  60 . The switching valve  92  is installed in the conduit  54 . The processing chamber  10  is evacuated by the vacuum pump  60  through the conduit  50  during the normal process of the wafer W. However, solid substances often adhere onto an inner surface of the conduit  50  due to the effect of the process gas  30  or the like. As described above, the switching valves  90  and  91  are opened to perform the error measurement and adjustment for the pressure gauge  80 . At this time, the interior of the processing chamber  10  is required to be evacuated up to the maximum vacuum level, which results in a prolonged process time. In addition, the adhesion of the solid substances onto the inner surface of the conduit  50  may deteriorate the exhaust efficiency. 
         [0046]    In the present embodiment, the bypass lines  51 ,  54 , and  56  are installed to directly connect the processing chamber  10  and the vacuum pump  60 . Accordingly, when adjusting the pressure gauge  80 , the switching valve  92  installed in the conduit  54  is opened such that the interior of the processing chamber  10  is exhausted through a series of the bypass lines  51 ,  54 , and  56 , as well as the conduit  50 . Among the bypass lines  51 ,  54  and  56 , the conduits  54  and  56  are not used during the normal process. Thus, no solid substances adhere onto the conduits  54  and  56  so that they are kept clean. Accordingly, when adjusting the pressure gauge  80 , by opening the switching valve  92  installed in the conduit  54  as well as the switching valves  90  and  91 , it is possible to efficiently perform the vacuum-exhaust operation through the bypass lines  51 ,  54 , and  56  and reduce the compensation time. 
         [0047]    As described above, the exhaust system and the substrate processing apparatus according to the present embodiment can not only accurately compensate the pressure gauge  80  but also shorten the compensation time. 
         [0048]    Further, the conduit  55  and the switching valve  93  are a bypass line and a switching valve, respectively, which are used in exhausting the interior of the processing chamber  10  to the extent of a pressure closer to atmospheric pressure when starting the operation of the vacuum pump  60 . The conduit  55  and the switching valve  93  have the same configuration as a general exhaust system. The conduits  54  and  55  are joined with each other at the conduit  56  that constitutes a portion of the bypass lines. In addition, the conduit  56  is connected to the conduit  50 . 
         [0049]    As described above, according to the pressure measuring device and the exhaust system using the same, and substrate processing apparatus according to the present embodiment, it is possible to accurately recognize an error caused in the pressure gauge  80  as a process pressure gauge and control the pressure adjustment valve  70  so as to compensate the error. Furthermore, even in such error compensation, it is possible to perform the compensation operation in a short period of time using the bypass lines  51 ,  54  and  56 . 
         [0050]      FIG. 2  is a view showing a pressure measuring device, an exhaust system, and a substrate processing apparatus, which have been conventionally used, according to a comparative example. In  FIG. 2 , the same components as those shown in  FIG. 1  will be designated by like reference numerals. Respective components shown in  FIG. 2  are the same as those shown in  FIG. 1  except for a pressure gauge  83  installed only when performing compensation. 
         [0051]    In  FIG. 2 , the pressure gauge  83  is connected only when checking an error of the pressure gauge  80 . In addition, the compensation performed by the pressure gauge  83  may be manually implemented, and is not fed back to the controller  100 . Thus, a compensation value obtained at the pressure gauge  83  is not reflected to a set pressure of the pressure adjustment valve  70 . In addition, the bypass lines  55  and  56  used at the time of starting the operation of the vacuum pump  60  are installed, while the conduit  54  as a bypass line for compensation is not installed. This makes it difficult to accurately recognize an error of the pressure gauge  80  and to compensate the pressure gauge  80  based on the recognized error. Accordingly, it can be seen that the pressure measuring device, the exhaust system and the substrate processing apparatus according to the embodiment have good configurations, compared to those in the comparative example. 
         [0052]    According to the present disclosure, it is possible to accurately recognize an error of a pressure gauge. 
         [0053]    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 without 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.