Patent Publication Number: US-2022230858-A1

Title: Window for plasma oes diagnosis, and plasma apparatus using same

Description:
FIELD 
     The present disclosure relates to a window device for diagnosing plasma OES (Optical Emission Spectroscopy), and more particularly, to a window device for diagnosing plasma OES that receives plasma light so that plasma diagnosis may be performed accurately. 
     DESCRIPTION OF RELATED ART 
     A process that may be performed on a semiconductor device using plasma may include a dry etching process or a chemical vapor deposition process. The process may use a plasma chamber that may generate plasma to perform the process. Therefore, a semiconductor substrate is placed on a substrate support in the plasma chamber. An inside of the plasma chamber is created under a predefined reaction condition. Then, the plasma is generated to perform the etching process and the chemical vapor deposition process. 
     When an abnormality occurs in a plasma process condition or anomalies occur in parts of plasma equipment, such as a mass flow controller, a RF source (radio frequency source), or a bias power, a plasma state changes. Thus, deposition or etching characteristics are changed accordingly. In this case, a quality of the process and reliability of the plasma equipment are deteriorated. In order to prevent this situation, a scheme for strictly monitoring the state of the plasma of the semiconductor apparatus is required. 
     A solution for monitoring the plasma state may use an OES (Optical Emission Spectroscopy) sensor. A plasma process diagnostic device using the OES sensor is disclosed in Korean Patent Application No. 10-2013-0090637. The plasma process diagnostic device according to this patent document includes multiple view ports that transmit light emitted from a process chamber to an outside, and multiple OES sensors connected to the view ports via optical cables. 
     However, the plasma process diagnostic device according to this patent document has a problem in that the view ports are easily contaminated because the view ports are directly installed in the process chamber. Thus, there is a difficulty in accurately diagnosing the plasma due to the contamination of the view ports. 
     DISCLOSURE 
     Technical Purposes 
     Therefore, a purpose of the present disclosure is to provide a window device for diagnosing plasma OES (Optical Emission Spectroscopy) in which contamination of an observation window that receives the plasma light is prevented, and the window device always receives the plasma light without lowering intensity of the plasma light so that the plasma state diagnosis may be performed accurately. 
     Technical Solutions 
     A first aspect of the present disclosure provides a window device for diagnosis of plasma OES (Optical Emission Spectroscopy), the window device comprising: a housing including a first chamber and a second chamber horizontally adjacent to each other; a connection opening defined in one face of the housing and between the first chamber and the second chamber, wherein the connection opening faces toward an opening through which light of plasma from a plasma chamber is exposed to the connection opening; an observation window opening defined in an opposite face of the housing opposite to the connection opening, wherein the observation window opening is coaxial with the connection opening, wherein the light of the plasma transmits through the observation window opening, and is incident to a light receiver of an OES sensor; an observation window positioned inside the observation window opening and in the housing; a winder and a rewinder installed in the first chamber and the second chamber, respectively; and a transparent film moving, in a roll-to-roll manner, from the rewinder to the winder while covering an inner face of the connection opening in the housing. 
     In one implementation, the window device further comprises contamination level identification means for identifying to contamination level of the transparent film exposed to the connection opening. 
     In one implementation, the window device further comprises a roll-to-roll driver, wherein when a contamination level identified by the contamination level identification means is greater than or equal to a predetermined value, the driver is configured to drive the winder and the rewinder such that the transparent film moves from the rewinder to the winder in a roll-to-roll manner by a predetermined length. 
     In one implementation, the window device further comprises: a connection opening sidewall extending outwardly from the connection opening while surrounding the connection opening; and a connection opening block received in an inner spaced defined by the connection opening sidewall, and having a through-hole defined therein. 
     In one implementation, the through-hole has an inner diameter of 1 to 5 mm. 
     In one implementation, the window device further comprises tension rollers respectively positioned at both opposing sides in a length direction of the connection opening so that the transparent film moves in the roll-to-roll manner while closely contacting an inner face of the connection opening. 
     In one implementation, the window device further comprises an optical fiber connector of the OES sensor installed out of the observation window opening. 
     In one implementation, the transparent film is heat-resistant and chemical-resistant. 
     A second aspect of the present disclosure provides a plasma apparatus including the window device for diagnosing plasma OES as defined above. 
     TECHNICAL EFFECTS 
     When using the window device for plasma OES diagnosis according to the present disclosure, the contamination of the observation window that receives plasma light for plasma state diagnosis may be prevented, and the window device always receives the plasma light without lowering intensity of the plasma light so that the plasma state diagnosis may be performed accurately. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view showing a configuration of a window device for plasma OES diagnosis according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTIONS 
     Hereinafter, a window device for plasma OES diagnosis according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. The present disclosure may be variously modified and may take many forms. Thus, specific embodiments will be illustrated in the drawings and described in detail herein. However, the specific embodiments are not intended to limit the present disclosure thereto. It should be understood that all changes, equivalents thereto, or substitutes therewith are included in a scope and spirit of the present disclosure. In drawings, like reference numerals have been used for like elements. For simplicity and clarity of illustration, elements in the figures are not necessarily drawn to scale. 
     It will be understood that, although the terms “first”, “second”, “third”, and so on may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section described below could be termed a second element, component, region, layer or section, without departing from the spirit and scope of the present disclosure. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present disclosure. As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes”, and “including” when used in this specification, specify the presence of the stated features, integers, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, operations, elements, components, and/or portions thereof. 
     Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
       FIG. 1  is a diagram showing a configuration of a window device for plasma OES diagnosis according to an embodiment of the present disclosure. 
     Referring to  FIG. 1 , the window device for plasma OES diagnosis according to an embodiment of the present disclosure includes a housing  110 , a connection opening  111 , an observation window opening  112 , an observation window  120 , a winder  131 , a rewinder  132 , a transparent film  140 , a tension roller  160 , contamination level identification means (not shown), and a roll-to-roll driver  150 . 
     The housing  110  includes a first chamber  113  and a second chamber  114  adjacent to each other. A shape of the housing  110  is not particularly limited. For example, the housing  110  may have a rectangular parallelepiped shape. 
     The connection opening  111  is positioned between the first chamber  113  and the second chamber  114  and is defined in one face of the housing  110  and communicates with an opening  11  through which plasma light is exposed and thus receives the plasma light from a plasma chamber  10 . 
     In this connection, the plasma chamber  10  refers to a process chamber that provides a reaction space for a process such as a thin film deposition on and an etching of a semiconductor substrate using plasma. The process chamber is supplied with a carrier gas and a process gas for plasma generation. 
     The observation window opening  112  is defined in an opposite face of the housing  110  opposite to the connection opening  111 . In this connection, the observation window opening  112  is coaxial with the connection opening  111 , such that the plasma light entering the connection opening  111  is transmitted thereto. The observation window opening  112  connects to a light receiver of an OES device. 
     The observation window  120  is positioned inside the observation window opening  112  and in the housing  110 . Any material that may transmit the plasma light therethrough may be used as a material of the observation window  120 . For example, the observation window  120  may be made of a quartz material. 
     The winder  131  and the rewinder  132  are installed inside the first chamber  113  and the second chamber  114 , respectively. In one example, the rewinder  132  may be installed in the first chamber  113 , while the winder  131  may be installed in the second chamber  114 . The transparent film  140  may be wound around the rewinder  132 . The winder  131  may pull the transparent film  140  wound around the rewinder  132  and wind around the winder. 
     The transparent film  140  may move in a roll-to-roll manner from the winder  132  to the winder  131  within the housing  110 . In this connection, the transparent film  140  may move in a roll-to-roll manner within the housing  110  while covering an inner face of the connection opening  111 . To this end, the housing  110  receives two tension rollers  160  respectively positioned on both opposing sides of the connection opening  111 . The tension roller  160  may support the transparent film  140  on an opposite face to one face of the transparent film  140  facing toward the inner face of the connection opening  111  so that the transparent film  140  is held in a tensioned manner in a form of a plane perpendicular to a direction in which the connection opening  111  faces toward the process chamber. The transparent film  140  may include a heat-resistant and chemical-resistant film. For example, the film  140  may be a polymer film made of PE, PP, or PI. 
     The contamination level identification means (not shown) refers to a device for identifying a contamination level of the transparent film  140  exposed through the connection opening  111  to the plasma. A predetermined value of the contamination level of the transparent film  140 , that is, an upper limit value of the contamination level of the transparent film  140  may be preset in the contamination level identification means. In one example, the contamination level identification means may be a vision inspection device. 
     The roll-to-roll driver  150  drives the winder  131  and the winder  132 . The roll-to-roll driver  150  may be a stepping motor mechanically connected to the rewinder  132 . The roll-to-roll driver  150  is electrically connected to the contamination level identification means. When the contamination level of the transparent film  140  identified by the contamination level identification means is the upper limit of the contamination level, the roll-to-roll driver  150  may drive the winder  131  and the winder  132  to move, in a roll-to-roll manner, the transparent film  140  by a predetermined length. The predetermined length may be set to be greater than or equal to a length of the transparent film  140  by which the film  140  is supported on the tension roller  160 . 
     In one example, the window device for plasma OES diagnosis according to an embodiment of the present disclosure further includes a connection opening sidewall  170  and a connection opening block  180 . 
     The connection opening sidewall  170  extends outwardly from the connection opening  111  while surrounding the connection opening  111 . That is, the connection opening sidewall  170  extends from a position of the housing at which the connection opening  111  is present and in a form of a tube surrounding the connection opening  111 . A distal end of the connection opening sidewall  170  surrounds the opening  11  of the plasma chamber  10  and is connected to the plasma chamber  10 . The connection opening sidewall  170  may have a flange portion  171  at the distal end thereof for connection to the plasma chamber  10 . The flange portion  171  may be closely fixed to an outer surface of the plasma chamber  10  so that the housing  110  is connected to the plasma chamber  10 . 
     The connection opening block  180  is inserted into an inner space defined by the connection opening sidewall  170  and has a through-hole  181  defined therein. A cross-sectional shape of the connection opening block  180  corresponds to a cross-sectional shape of the connection opening sidewall  170 . The through-hole  181  extends in a parallel manner to a longitudinal direction of the connection opening sidewall  170  and communicates with the opening  11  of the plasma chamber  10 . The through-hole  181  has an inner diameter of 1 to 5 mm. In one example, the through-hole  181  may be provided to have a diameter of 4 mm. This connection opening block  180  may be made of an opaque material and may be absorbent. Therefore, horizontally straight plasma light may be easily guided in a direction toward the observation window  120 . 
     The connection opening sidewall  170  and the connection opening block  180  may allow the plasma light from the opening  11  of the plasma chamber  10  to be directed to towards the observation window  120 . In other words, the connection opening block  180  may act as a collimator to improve straightness of light. Therefore, the through-hole  181  of the connection opening block  180  improves the straightness of the plasma light traveling toward the observation window  120  and thus lowers conductance of the plasma. 
     When the connection opening sidewall  170  and the connection opening block  180  are provided, the tension roller  160  is positioned at each of both opposing sides around the through-hole  181  to allow one face of the transparent film  140  facing toward the through-hole  181  to be in close contact with the connection opening block  180 . 
     In one example, the window device for plasma OES diagnosis according to an embodiment of the present disclosure further includes an optical fiber connector  190 . 
     The optical fiber connector  190  is connected to an optical fiber of the OES (Optical Emission Spectroscopy) sensor for OES diagnosis of the plasma and is disposed out of the observation window opening  112  and is in close contact with the observation window  120 . In one example, the optical fiber connector  190  may include an annular housing connector  191  and an optical fiber connection port  192  extending from the housing connector  191 . In this case, the housing connector  191  may be fixed to an outer face of the housing  110  so as to cover an edge of the observation window  120 . 
     Hereinafter, a process in which the window device for plasma OES diagnosis according to an embodiment of the present disclosure receives the plasma light and then transmits the same to the OES sensor will be described. 
     The plasma light of the plasma generated in the plasma chamber  10  is emitted through the opening  11  of the plasma chamber  10  and travels toward the connection opening block  180  facing toward the opening  11  of the plasma chamber  10 . 
     The emitted plasma light enters the through-hole  181  of the connection opening block  180  and travels toward the transparent film  140  along the through-hole  181 . In this connection, while the plasma light travels along the narrow through-hole  181 , the straightness thereof is improved. 
     The plasma light passing through the through-hole  181  transmits through the transparent film  140 . Then, the plasma light passing through the transparent film  140  travels toward the observation window opening  112 . 
     The plasma light travelling toward the observation window opening  112  enters the observation window opening  112  and then transmits through the observation window  120 . The plasma light passing through the observation window  120  enters an inside of the optical fiber connector  190 . 
     The plasma light entering the optical fiber connector  190  is transmitted to the OES sensor via an optical fiber connected to the optical fiber connector  190 . Thus, the OES sensor may diagnose the plasma state based on an analyzing result of the transmitted plasma light. 
     During this process, the contamination level identification means identifies the contamination level of the transparent film  140 . In this connection, when the contamination level of the transparent film  140  is the preset upper limit of the contamination level, the means may deliver a signal indicating this event to the roll-to-roll driver  150 . 
     The roll-to-roll driver  150  drives the winder  131  and the rewinder  132  when the signal from the contamination level identification means is input thereto. Thus, the transparent film  140  may move from the rewinder to the winder  131  and may be wound around the winder  131  by at least one a predefined length of the transparent film  140  corresponding to a diameter of the through-hole  181  of the connection opening block  180  such that a portion of the predefined length of the transparent film  140  is spaced from the through-hole  181 . For example, at least a length of a portion of the transparent film  140  supported on the two tension rollers  160  may move toward the winder and may be wound around the winder  131 . Accordingly, a contaminated portion of the transparent film  140  is spaced apart from the through-hole  181 , and thus, a new uncontaminated portion of the transparent film  140  faces toward the through-hole  181 . 
     The contamination level identification means continues to measure the contamination level of the transparent film  140  even in a process of replacing the contaminated portion of the transparent film  140  with the new uncontaminated portion thereof via the roll-to-roll movement of the transparent film  140 . 
     In the window device for plasma OES diagnosis according to an embodiment of the present disclosure, the observation window  120  is not directly installed on the plasma chamber  10 . Rather, a separate installation space for the observation window  120  is defined through the housing  110 . Thus, the observation window  120  to receive the plasma light is spaced away from the plasma chamber  10 . 
     In addition, the first chamber  113  and the second chamber  114  of the housing  110  accommodate therein the winder  131  and the rewinder  132 , respectively, and the transparent film  140  moves, in the roll-to-roll manner, from the rewinder  132  to the winder  131 . The transparent film  140  covers the inner face of the connection opening  111  communicating with the opening  11  through the plasma light of the plasma chamber  10  is exposed. Thus, the transparent film  140  may prevent the carrier gas and the process gas together with the plasma light emitted from the opening  11  of the plasma chamber  10  from entering the housing  110 . Thus, the observation window  120  is prevented from being contaminated with the gases. 
     Further, the transparent film  140  may be contaminated with the gases emitted from the opening  11  of the plasma chamber  10 . However, the transparent film  140  may move in a roll-to-roll manner. Thus, when a portion of the film  140  corresponding to the opening  11  of the plasma chamber  10  has been contaminated to have a contamination level of the upper limit value as measured by the contamination level identification means, another portion of the film  140  that is not contaminated may be positioned to face toward the opening  11  of the plasma chamber  10 . Accordingly, the transparent film  140  through which the plasma light transmits may be replaced and maintained in a clean state or a state with a low contamination level at all times. The plasma light that passes through the transparent film  140  and travels toward the observation window  120  may not have decrease in intensity. Therefore, an accurate diagnosis of the state of the plasma based on the plasma light may be achieved. 
     Further, between the housing  110  and the opening  11  of the plasma chamber  10 , the connection opening sidewall  170  and the connection opening block  180  may be disposed. The connection opening block  180  may be received within the inner space defined by the connection opening sidewall  170  and have the through-hole  181  communicating with the opening  11  of the plasma chamber  10 . Thus, as the plasma light which is emitted from the opening  11  of the plasma chamber  10  and travels toward the observation window  120  passes through a small diameter of the through-hole  181 , the straightness thereof may be improved. Accordingly, the plasma light may be easily transmitted to the observation window  120  positioned far away from the plasma chamber  10 , so that the plasma light may be incident into the observation window  120  without loss thereof. This may increase the accurate diagnosis efficiency of the plasma state. 
     Therefore, when using the window device for plasma OES diagnosis according to an embodiment of the present disclosure, the contamination of the observation window  120  that receives the plasma light for plasma state diagnosis may be prevented. Further, the window device always receives the plasma light without lowering intensity of the plasma light so that the plasma state diagnosis may be performed accurately. 
     In one example, the window device for plasma OES diagnosis according to an embodiment of the present disclosure may be included in the plasma apparatus. Therefore, the disclosure may provide a plasma apparatus in which the window device for diagnosing plasma OES is installed. The plasma apparatus has the window device for diagnosing plasma OES according to an embodiment of the present disclosure, so that accurate diagnosis of plasma treatment of the semiconductor substrate, etc. and the plasma state may be achieved. 
     Descriptions of the presented embodiments are provided so that any person with ordinary skill in the art of the present disclosure may use or practice the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art of the present disclosure. The general principles defined herein may be applied to other embodiments without departing from the scope of the present disclosure. Thus, the present disclosure is not to be limited to the embodiments presented herein, but is to be construed in the widest scope consistent with the principles and novel features presented herein.