Patent Publication Number: US-2023162949-A1

Title: Apparatus for processing substrate

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from Korean Patent Application No. 10-2021-0160758 filed on Nov. 19, 2021 in the Korean Intellectual Property Office, and all the benefits accruing therefrom under 35 U.S.C. 119, the contents of which in its entirety are herein incorporated by reference. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to an apparatus for processing a substrate. 
     2. Description of the Related Art 
     Plasma is generated by a very high temperature, a strong electric field, or radio-frequency (RF) electromagnetic fields, and refers to an ionized gas state composed of ions, electrons, radicals, and the like. Semiconductor device manufacturing utilizes plasma in carrying out various processes. 
     In general, a substrate processing apparatus for generating plasma with microwaves utilizes an antenna and a dielectric plate to transmit the microwaves internally of a chamber in which a substrate is arranged. 
     SUMMARY 
     Aspects of the present disclosure provide a substrate processing apparatus that transmits focused microwaves to a substrate. 
     However, aspects of the present disclosure are not restricted to those set forth herein. The above and other aspects of the present disclosure will become more apparent to one of ordinary skill in the art to which the present disclosure pertains by referencing the detailed description of the present disclosure given below. 
     According to an aspect of the present disclosure, there is provided an apparatus for processing a substrate, including a process chamber configured to define an interior space for internally processing a substrate, a substrate support unit configured to support the substrate in the interior space, a dielectric plate disposed above the substrate support unit, an antenna unit disposed over or above the dielectric plate, shaped into a frustum, having a truncated cone or prismoidal shape, and including a through-hole, a microwave application unit configured to apply microwaves to the antenna unit, and a slow-wave plate disposed on the antenna unit. 
     The antenna unit may have a bottom end that is in contact with an edge of the dielectric plate, and the apparatus for processing a substrate may further include an air gap interposed between the antenna unit and the dielectric plate. 
     The slow-wave plate may surround the outer surfaces of the antenna unit. 
     The antenna unit may be shaped into a truncated cone. 
     The antenna unit may be shaped into a truncated triangular pyramid. 
     The antenna unit may have first, second, and third side surfaces which have a common inclination with respect to the top surface of the dielectric plate. 
     The antenna unit may have side surfaces formed with a plurality of slots. 
     The antenna unit may have a trapezoidal cross section cut in a direction perpendicular to the top surface of the dielectric plate. 
     The antenna unit may have varying cross-sections cut in a direction parallel to the top surface of the dielectric plate to provide gradually increasing cross-sections from the top to bottom ends of the antenna unit. 
     According to another aspect of the present disclosure, there is provided an apparatus for processing a substrate, including a process chamber configured to define an interior space for internally processing a substrate, a substrate support unit configured to support the substrate in the interior space, a dielectric plate disposed above the substrate support unit, an antenna unit disposed over or above the dielectric plate and including side surfaces inclined with respect to a top surface of the dielectric plate, and a microwave application unit configured to apply microwaves to the antenna unit. Here, the antenna unit has a top end that is connected to the bottom end of the microwave application unit, the side surfaces of the antenna unit have a bottom end that is in contact with an edge of the dielectric plate, and the bottom end of the antenna unit is larger than the top end of the antenna unit in cross-section as taken in a direction parallel to the top surface of the dielectric plate. 
     The side surfaces of the antenna unit may be inclined and connected to the top surface of the dielectric plate at an inclination angle of less than 90 degrees. 
     The apparatus for processing a substrate may further include a through-hole formed between the top end of the antenna unit and the bottom end of the antenna unit. 
     The apparatus for processing a substrate may further include a slow-wave plate disposed on the antenna unit and surrounding the inclined side surfaces of the antenna unit. 
     The antenna unit may have a trapezoidal cross section cut in a direction perpendicular to the top surface of the dielectric plate. 
     The apparatus for processing a substrate may further include an air gap interposed between the antenna unit and the dielectric plate. 
     According to yet another aspect of the present disclosure, there is provided an apparatus for processing a substrate, including a process chamber configured to define an interior space for internally processing a substrate, a substrate support unit configured to support the substrate in the interior space, a dielectric plate disposed above the substrate support unit, an antenna unit disposed over or above the dielectric plate and including side surfaces inclined with respect to a top surface of the dielectric plate, and a microwave application unit configured to apply microwaves to the antenna unit. Here, the antenna unit has a trapezoidal cross section cut in a direction perpendicular to the top surface of the dielectric plate. 
     The antenna unit may have the side surfaces inclined and formed with a plurality of slots. 
     The apparatus for processing a substrate may further include a slow-wave plate disposed on the antenna unit and surrounding the inclined side surfaces of the antenna unit. 
     The antenna unit may have varying cross-sections cut in a direction parallel to the top surface of the dielectric plate to provide gradually increasing cross-sections from the top to bottom ends of the antenna unit. 
     The apparatus for processing a substrate may further include an air gap between the antenna unit and the dielectric plate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects and features of the present disclosure will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which: 
         FIG.  1    is a diagram illustrating a substrate processing apparatus  10  according to at least one embodiment of the present disclosure. 
         FIG.  2    is a diagram illustrating an antenna of the substrate processing apparatus  10  according to at least one embodiment of the present disclosure. 
         FIG.  3    is a diagram for explaining a substrate processing method performed by a substrate processing according to at least one embodiment of the present disclosure. 
         FIG.  4    is a plan view of an antenna and a substrate of a substrate processing apparatus according to at least one embodiment of the present disclosure. 
         FIG.  5    is a diagram illustrating an antenna of a substrate processing apparatus according to another embodiment of the present disclosure. 
         FIG.  6    is a diagram illustrating an antenna of a substrate processing apparatus according to yet another embodiment of the present disclosure. 
         FIG.  7    is a diagram illustrating an antenna of a substrate processing apparatus according to yet another embodiment of the present disclosure. 
     
    
    
       
     
       
         
           
               
             
               
                   
               
               
                 REFERENCE NUMERALS 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 10: substrate processing apparatus 
                 100: process chamber 
               
               
                 101: processing space 
                 102: exhaust hole 
               
               
                 105: gas supply hole 
                 110: body 
               
               
                 120: cover 
                 131: exhaust line 
               
               
                 200: substrate support unit 
                 210: support plate 
               
               
                 220: heater 
                 230: support shaft 
               
               
                 300: gas supply unit 
                 400: microwave application unit 
               
               
                 410: microwave generator 
                 420: first waveguide 
               
               
                 430: second waveguide 
                 432: outer conductor 
               
               
                 434: inner conductor 
                 440: phase converter 
               
               
                 450: matching network 
                 500: antenna unit 
               
               
                 501-503: first-third side surfaces 
                 510: slot 
               
               
                 520: side surfaces 
                 600: slow-wave plate 
               
               
                 700: dielectric plate 
                 AG: air gap 
               
               
                 W: substrate 
               
               
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Advantages and features of the present disclosure and methods of accomplishing the same may be understood more readily by reference to the following detailed description of exemplary embodiments and the accompanying drawings. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of the disclosure to those skilled in the art, and the present disclosure will only be defined by the appended claims. 
     It will also be understood that when an element or a layer is referred to as being “on” another element or layer, it can be not only directly on the other element or layer, but also indirectly thereon with intervening elements or layers being present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. 
     Spatially relative terms, such as “below,” “beneath,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to convey one element&#39;s or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the drawings. For example, when a device in the drawings is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the illustrative term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein may be interpreted accordingly. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, and/or sections, these elements, components, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, or section from another element, component, or section. Thus, a first element, first component, or first section discussed below could be termed a second element, second component, or second section without departing from the teachings of the present disclosure. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a,” “an” and “the” 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/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups 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. 
     Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, like reference numerals designate like elements, although the elements are shown in different drawings. Further, in the following description of some embodiments, a detailed description of related known components and functions when considered to obscure the subject of the present disclosure will be omitted for the purpose of clarity and for brevity. 
       FIG.  1    is a diagram illustrating a substrate processing apparatus  10  according to at least one embodiment of the present disclosure.  FIG.  2    is a diagram illustrating an antenna of the substrate processing apparatus  10  according to at least one embodiment of the present disclosure. 
     Referring to  FIGS.  1  and  2   , the substrate processing apparatus  10  includes a process chamber  100 , a substrate support unit  200 , a gas supply unit  300 , a microwave application unit  400 , an antenna unit  50 , a slow-wave plate  600 , and a dielectric plate  700 . 
     The process chamber  100  is internally formed with a processing space  101  which is provided as a space in which a substrate W is processed. The process chamber  100  includes a body  110  and a cover  120 . The body  110  has open upper surfaces and is internally formed with a space. The cover  120  is placed on the upper end of the body  110  and seals the open upper surfaces of the body  110 . The cover  120  has a lower end formed with an internal step to provide the process chamber  100  with an upper space that is larger and a lower space that is smaller in radius. 
     The process chamber  100  has a bottom surface that may be formed with an exhaust hole  102 . The exhaust hole  102  is connected to an exhaust line  131 . By exhausting through the exhaust line  131 , the inside of the process chamber  100  may be maintained at a pressure lower than normal pressure. Additionally, reaction by-products generated during the process and gas remaining in the process chamber  100  may be discharged to the outside through the exhaust line  131 . 
     Although not shown in  FIG.  1   , a substrate entrance may be formed on one sidewall of the process chamber  100 . The substrate entrance may be opened and closed by a door. 
     The substrate support unit  200  supports the substrate W in the processing space  140 . The substrate support unit  200  includes a support plate  210 , a heater  220 , and a support shaft  230 . 
     The support plate  210  has a predetermined thickness and is provided as a disk having a larger radius than the substrate W. The substrate W is placed on the upper surface of the support plate  210 . According to at least one embodiment, the support plate  210  is not provided with a structure for fixing the substrate W, and the substrate W is put up for the process while being placed on the upper surface of the support plate  210 . Alternatively, the support plate  210  may be provided as an electrostatic chuck for fixing the substrate W by using an electrostatic force or as a chuck for fixing the substrate W by using a mechanical clamping method. 
     Multiple lift pins are provided and are respectively located in pin holes (not shown) formed in the support plate  210 . The lift pins move in the vertical direction along the pin holes and may load the substrate W onto the support plate  210  or unload the substrate W placed on the support plate  210 . 
     The heater  220  is provided inside the support plate  210 . The heater  220  is provided as a spiral coil and may be embedded in the support plate  210  at uniform intervals. The heater  220  is connected to an external power source (not shown) and generates heat by resisting current applied from the external power source. The generated heat is transferred to the substrate W through the support plate  210  and heats the substrate W to a predetermined temperature. 
     The support shaft  230  is positioned under the support plate  210  and supports thereof. 
     A gas supply unit  300  supplies a process gas to the processing space  140 . Although not shown in  FIG.  1   , the gas supply unit  300  may include a gas storage unit, a valve, and a gas supply line. The valve may open and close the gas supply line and regulate the supply flow rate of the process gas. The gas supply unit  300  may supply the process gas stored in the gas storage unit into the process chamber  100  through a gas supply hole  105  formed in a sidewall of the process chamber  100  and through a gas supply line. Multiples of the gas supply hole  105  may be provided. 
     The microwave application unit  400  applies microwaves to the antenna unit  500 . The microwave application unit  400  includes a microwave generator  410 , a first waveguide  420 , a second waveguide  430 , a phase converter  440 , and a matching network  450 . 
     The microwave generator  410  generates microwaves needed to excite the process gas into a plasma state. 
     The first waveguide  420  is connected to the microwave generator  410  and is internally formed with a passage. The microwaves generated by the microwave generator  410  are transmitted to the phase converter  440  along the first waveguide  420 . 
     The second waveguide  430  includes an outer conductor  432  and an inner conductor  434 . 
     The outer conductor  432  extends downward in the vertical direction from the end of the first waveguide  420  and is internally formed with a passage. The outer conductor  432  has an upper end connected to the lower end of the first waveguide  420  and a lower end connected to the upper end of the cover  120 . 
     The inner conductor  434  is located within the outer conductor  432 . The inner conductor  434  is provided as a cylindrical rod, and the longitudinal direction thereof is arranged parallel to the vertical direction. The inner conductor  434  has its upper end fixedly inserted in the lower end of the phase converter  440 . The inner conductor  434  extends downward and has its lower end located inside the process chamber  100 . The lower end of the inner conductor  434  is fixedly coupled to the center of the antenna unit  500 . Specifically, the lower end of the inner conductor  434  is coupled to an antenna-unit top  500 _top of the antenna unit  500 . The inner conductor  434  may be provided by sequentially coating a first plating layer and a second plating layer on a copper rod. According to at least one embodiment, the first plating layer may be made of nickel (Ni), and the second plating layer may be made of gold (Au). Microwaves are mainly propagated through the first plating film to the antenna unit  500 . 
     The phase-converted microwave in the phase converter  440  is transmitted to the antenna unit  500  along the second waveguide  430 . 
     The phase converter  440  is provided at a point where the first waveguide  420  connects to the second waveguide  430  and changes the phase of the microwave. The phase converter  440  may be provided in the shape of a cone having a pointed bottom. The phase converter  440  propagates the microwave transmitted from the first waveguide  420  to the second waveguide  430  with the microwave mode converted. The phase converter  440  may convert the microwave from a transverse electric (TE) mode to a transverse electromagnetic (TEM) mode. 
     The matching network  450  is provided in the first waveguide  420 . The matching network  450  matches the microwave propagating through the first waveguide  420  to a predetermined frequency. 
     The antenna unit  500  may be arranged over or above the substrate support unit  200  and the dielectric plate  700  to face the support plate  210 . The antenna-unit top  500 _top may be connected to the inner conductor  434  of the second waveguide  430 . Specifically, the antenna-unit top  500 _top may surround the inner conductor  434 , and the lower end of the inner conductor  434  may be fitted into a hole defined by the antenna-unit top  500 _top. The antenna unit  500  has an antenna-unit bottom  500 _bottom that may be in contact an edge portion of the top surface of the dielectric plate  700 . 
     The antenna unit  500  may be shaped into a frustum, having a truncated cone or prismoidal shape. For example, the antenna unit  500  may be provided in a thin truncated cone shape. The antenna-unit top  500 _top may be unpointed and may have a flat circular shape in cross section of a cone shape that is cut midway. 
     The antenna-unit bottom  500 _bottom has a larger radius than the antenna-unit top  500 _top. Specifically, the cross-sectional area gradually increases from the antenna-unit top  500 _top to the antenna-unit bottom  500 _bottom. Accordingly, side surfaces  520  of the antenna unit  500  interconnecting the antenna-unit top  500 _top and the antenna-unit bottom  500 _bottom may meet the top surface of the dielectric plate  700  at a certain angle θ. In other words, the antenna unit  500  is neither planar nor parallel to the top surface of the dielectric plate  700  but may incline. The certain angle formed between the side surfaces  520  of the antenna unit  500  and the top surface of the dielectric plate  700  may be varied according to embodiments. 
     The side surfaces  520  of the antenna unit  500  may be arranged in an inclined shape with respect to the top surface of the dielectric plate  700 . Specifically, the side surfaces  520  of the antenna unit  500  do not perpendicularly meet the top surface of the dielectric plate  700 , but the side surfaces  520  inclined at an angle of less than 90 degrees meet the top surface of the dielectric plate  700 . A cross section of the antenna unit  500  cut perpendicular to the top surface of the dielectric plate  700  may have a trapezoidal shape. 
     The antenna unit  500  may have a truncated cone shape of a thin curved sheet in which a through-hole is formed between the antenna-unit top  500 _top and the antenna-unit bottom  500 _bottom. 
     The side surfaces  520  of the antenna unit  500  may be formed with a plurality of slots  510 . For example, a plurality of slots  510  may be uniformly distributed on the side surfaces  520  of the antenna unit  500 . For another example, over the side surfaces  520  of the antenna unit  500 , the closer to the antenna-unit top  500 _top, the more densely the slots  510  may be arranged, and the closer to the antenna-unit bottom  500 _bottom, the more sparsely the slots  510  may be arranged. The plurality of slots  510  may be provided in a ‘+’ shape or an ‘×’ shape. However, the embodiments are not limited thereto, and the shape and arrangement of the slots  150  may be variously modified. 
     The slow-wave plate  600  is located on the antenna unit  500  and may be provided as a disk having predetermined thicknesses. The slow-wave plate  600  may have a radius corresponding to the inner side of the cover  120 . The slow-wave plate  600  is provided with a dielectric material such as alumina or quartz. Microwaves propagated in the vertical direction through the inner conductor  434  proceed in the radial direction of the slow-wave plate  600 . The microwave propagated to the slow-wave plate  600  has its wavelength compressed and is resonated. The slow-wave plate  600  may contact the upper surface of the antenna unit  500 . Specifically, the lower surface of the slow-wave plate  600  may surround the outer surface of the antenna unit  500 . 
     The dielectric plate  700  is positioned under the antenna unit  500  and may be provided as a disk having predetermined thicknesses. The dielectric plate  700  may be provided with a dielectric material such as alumina or quartz. The bottom surface of the dielectric plate  700  may have an inwardly concave or recessed surface. The dielectric plate  700  may have its bottom surface positioned at the same elevation as the lower end of the cover  120 . The dielectric plate  700  may have its side formed to be stepped providing a middle portion with a larger radius than the lower ends thereof. The surface lower than the middle portion of the dielectric plate  700  may be placed on the stepped lower end of the cover  120 . The lower end of the dielectric plate  700  may have a smaller radius than the lower end of the cover  120  and may maintain a predetermined distance from the lower end of the cover  120 . The microwave is radiated through the dielectric plate  700  to the processing space  101  of the process chamber  100 . 
     An air gap AG may be formed between the antenna unit  500  and the dielectric plate  700 . Specifically, the antenna unit  500  and the dielectric plate  700  do not completely contact each other, which allows a space to be formed between the bottom of the antenna unit  500  and the top of the dielectric plate  700 . 
       FIG.  3    is a diagram for explaining a substrate processing method performed by a substrate processing according to at least one embodiment of the present disclosure.  FIG.  4    is a plan view of an antenna and a substrate of a substrate processing apparatus according to at least one embodiment of the present disclosure. 
     Referring to  FIGS.  3  and  4   , the antenna unit  500  may be disposed over the substrate W to overlap the same. In particular, the cross-sectional area of the antenna-unit top  500 _top may be smaller than that of the substrate W, and the cross-sectional area of the antenna-unit bottom  500 _bottom may be greater than that of the substrate W. 
     Microwaves passing through the antenna unit  500  shaped as a frustum are not transmitted perpendicularly to the substrate W but may be deflected while passing through the side surfaces  520  of the antenna unit  500 . In other words, the microwaves transmitted through the side surfaces  520  of the antenna unit  500  that is not arranged parallel to the substrate W but at a specific angle θ with the substrate W are focused and delivered to the substrate W. 
       FIG.  5    is a diagram illustrating an antenna of a substrate processing apparatus according to another embodiment of the present disclosure.  FIG.  6    is a diagram illustrating an antenna of a substrate processing apparatus according to yet another embodiment of the present disclosure.  FIG.  7    is a diagram illustrating an antenna of a substrate processing apparatus according to yet another embodiment of the present disclosure. For the convenience of explanation, the following focuses on details different from those described with reference to  FIG.  2   . 
     Referring to  FIG.  5   , the antenna unit  500  may be shaped into a truncated triangular pyramid. Specifically, the antenna unit  500  may have first, second and third side surfaces  501  to  503 . The first to third side surfaces  501  to  503  may have first, second and third angles θ 1  to θ 3  with respect to the top surface of the dielectric plate  700 . For example, all of the first to third angles θ 1  to θ 3  may be the same. As another example, the first to third angles θ 1  to θ 3  may be different from each other. The first to third side surfaces  501  to  503  may not perpendicularly meet the top surface of the dielectric plate  700 , but may meet the same at an acute angle smaller than 90 degrees. 
     The first to third side surfaces  501  to  503  may each have a trapezoidal shape. 
     The antenna unit  500  may have a triangular antenna-unit top  500 _top and a triangular antenna-unit bottom  500 _bottom. Accordingly, the antenna unit  500  may have an inner conductor  434  with a lower end that is triangular in cross section to conform and connect to the triangular antenna-unit top  500 _top. The cross section of the triangular shape of the antenna-unit bottom  500 _bottom is larger than the cross section of the substrate W. 
     The slow-wave plate  600  disposed over or above the antenna unit  500  may surround the first to third sides  501 - 503  of the antenna unit  500 . For example, the slow-wave plate  600  may conformally contact the first to third side surfaces  501  to  503  of the antenna unit  500 . 
     Referring to  FIG.  6   , the antenna unit  500  may have a dome shape with the top removed from the hemisphere. In this case, the antenna unit  500  may have a circular antenna-unit top  500 _top and a circular antenna-unit bottom  500 _bottom. A cross-section cut parallel to the top surface of the dielectric plate  700  gradually increases from the circular antenna-unit top  500 _top to the circular antenna-unit bottom  500 _bottom. The cross-section of the circular antenna-unit bottom  500 _bottom is larger than that of the substrate W. 
     Referring to  FIG.  7   , the antenna unit  500  may be shaped into a truncated quadrangular pyramid with the top removed from the quadrangular pyramid. In this case, the antenna unit  500  may have a rectangular antenna-unit top  500 _top and a rectangular antenna-unit bottom  500 _bottom. The antenna unit  500  may have first to fourth side surfaces. The first to fourth side surfaces may have one or more certain angles with respect to the top surface of the dielectric plate  700 . The first to fourth side surfaces may each meet the edge portion of the top surface of the dielectric plate  700  at an inclination angle with respect to the top surface of the dielectric plate  700 . 
     From the rectangular antenna-unit top  500 _top to the rectangular antenna-unit bottom  500 _bottom, the quadrangle, which is a cross-section cut parallel to the top surface of the dielectric plate  700 , gradually increases. 
     While some embodiments of the present disclosure have been particularly shown and described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the technical idea and scope of the present disclosure as defined by the following claims.