Patent Publication Number: US-11047043-B2

Title: Chamber liner for high temperature processing

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of co-pending U.S. patent application Ser. No. 15/434,853, filed Feb. 16, 2017, which claims benefit of U.S. provisional patent application Ser. No. 62/313,229, filed Mar. 25, 2016, which is hereby incorporated herein by reference. 
    
    
     BACKGROUND 
     Field of the Disclosure 
     Embodiments described herein generally relate to a chamber liner for a semiconductor process chamber and a semiconductor process chamber having a chamber liner. More specifically, embodiments disclosed herein relate to a chamber liner for processing temperatures greater than about 650 degrees Celsius while shielding chamber components from halogen damage. 
     Description of the Related Art 
     In the fabrication of integrated circuits, deposition processes such as chemical vapor deposition (CVD) or plasma enhanced CVD processes are used to deposit films of various materials upon semiconductor substrates. These depositions may take place in an enclosed process chamber. The process gases used in the depositions deposit films on the substrate, but may also deposit residue on the internal walls and other components of the process chamber. This residue builds up as more substrates are processed in the chamber and leads to generation of particles and other contaminants. These particles and contaminants can lead to the degradation of the deposited films on the substrates causing product quality issues. Process chambers must be periodically cleaned to remove the deposited residue on the chamber components. 
     A chamber liner may be disposed in the chamber to define a processing region in a desired location within the chamber with respect to the substrate. The chamber liner may be configured to assist in confining the plasma to the processing region and help prevent other components in the chamber from being contaminated with deposited materials, such as the residue mentioned above. The process gases may be supplied above a substrate support. A purge gas may be provided from below the substrate support to prevent process gases from reaching areas at the bottom of the chamber and causing deposit of residue in the areas below the substrate support. The process gas and the purge gas may be removed from the process chamber using a common exhaust disposed away from the process area, such as around an outer perimeter of the process chamber, to prevent mixing of the purge gas with the process gas in the process area. Using the arrangement described above, particle formation can occur in the process area above the substrate and cause defects in the products made in the process chamber. 
     Furthermore, substrate processing temperatures are typically capped between about 400 degrees Celsius and about 480 degrees Celsius for silicon based depositions due to the aggressive erosion and corrosion by the halogen clean on the high temperature components. As such, optimal film quality is often sacrificed due to manufacturability and reliability concerns. 
     Thus, there is a need for an improved liner for a process chamber to prevent particle formation and/or to permit significantly higher substrate processing temperatures while shielding sensitive components from halogen damage. 
     SUMMARY 
     Embodiments disclosed herein generally relate to chamber liners used to optimize flow profiles is a plasma process chamber. The chamber liners disclosed herein may allow for the high temperature processing of substrates in a processing chamber. The processing chamber utilizes an inert bottom purge flow to shield the substrate support from halogen reactants such that the substrate support may be heated to temperatures greater than about 650 degrees Celsius. The chamber liner controls a flow profile such that during deposition the bottom purge flow restricts reactants and by-products from depositing below the substrate support. During a clean process, the bottom purge flow restricts halogen reactants from contacting the substrate support. As such, the chamber liner includes a conical inner surface angled inwardly to direct purge gases around an edge of the substrate support and to reduce deposition under the substrate support and on the edge of the substrate. 
     In one embodiment, a chamber liner is disclosed. The chamber liner includes an annular bottom portion defining an opening in a center region therein and a sidewall portion extending from the annular bottom portion. The sidewall portion has a first inner surface, a second inner surface, and a conical inner surface connecting the first inner surface and the second inner surface. The first inner surface is adjacent the annular bottom portion and has a first diameter. The second inner surface has a second diameter. The second diameter is less than the first diameter. The conical inner surface extends between the first inner surface and the second inner surface and is angled inwardly from the first inner surface to the second inner surface. 
     In another embodiment, a chamber liner is disclosed. The chamber liner includes an annular bottom portion defining an opening in a center region therein and a sidewall portion extending from the annular bottom portion. The sidewall portion has a first inner surface, a second inner surface, and a conical inner surface. The first inner surface is adjacent the annular bottom portion and has a first diameter. The second inner surface has a second diameter. The second diameter is less than the first diameter. The conical inner surface extends between the first inner surface and the second inner surface. Furthermore, the conical inner surface is angled inwardly from the first inner surface to the second inner surface at an angle of between about 30 degrees and about 75 degrees relative to a horizontal plane defined by the annular bottom portion. 
     In another embodiment, a processing chamber is disclosed. The processing chamber includes a chamber body defining a processing volume, a substrate support disposed in the processing volume, and a liner disposed in the processing volume adjacent the substrate support. The liner includes an annular bottom portion defining an opening in a center region therein and a sidewall portion extending from the annular bottom portion. The sidewall portion has a first inner surface, a second inner surface, and a conical inner surface. The first inner surface is adjacent the annular bottom portion and has a first diameter. The second inner surface has a second diameter. The second diameter is less than the first diameter. The conical inner surface extends between the first inner surface and the second inner surface and is angled inwardly from the first inner surface to the second inner surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. 
         FIG. 1A  is a side sectional view of a process chamber including a chamber liner disposed around a substrate support in a raised position, according to one embodiment of the disclosure. 
         FIG. 1B  is a side sectional view of the process chamber including the chamber liner disposed around the substrate support in a lowered position, according to one embodiment of the disclosure. 
         FIG. 2A  is a cross-sectional side view of the chamber liner, according to one embodiment of the disclosure. 
         FIG. 2B  is an enlarged cross-sectional side sectional view of a portion of the chamber liner, according to another embodiment of the disclosure. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. 
     DETAILED DESCRIPTION 
     Embodiments disclosed herein generally relate to a chamber liner for the high temperature processing of substrates in a processing chamber. The processing chamber utilizes an inert bottom purge flow to shield the substrate support from halogen reactants such that the substrate support may be heated to temperatures greater than about 650 degrees Celsius. The chamber liner controls a flow profile such that during deposition the bottom purge flow restricts reactants and by-products from depositing below the substrate support. During a clean process, the bottom purge flow restricts halogen reactants from contacting the substrate support. As such, the chamber liner includes a conical inner surface angled inwardly to direct purge gases around an edge of the substrate support and to reduce deposition under the substrate support and the on the edge. 
       FIG. 1A  is a side sectional view of a process chamber  100  including a chamber liner  130  disposed around the substrate support  120  in a raised position  117 , according to one embodiment of the disclosure.  FIG. 1B  is a side sectional view of the process chamber  100  including the chamber liner  130  disposed around the substrate support  120  in a lowered position  118 , according to one embodiment of the disclosure. The sectional views of  FIGS. 1A and 1B  as well as  FIGS. 2A and 2B  shown below are cross-sectional views, so that parts behind or at other depths through the plane of the Figure are not shown in the drawings for clarity. For example,  FIG. 1A  may further include additional parts of a process kit, however, certain parts were omitted in order to not clutter the drawing and to make the gas flow of the process gas and purge gas discussed below easier to understand. 
     The chamber liner  130  is configured to reduce particle deposition on the chamber components and prevent purge gas from entering a process volume  109  above the substrate support  120 , which advantageously reduces defects and increases the service interval. The chamber liner  130  controls a flow profile of a purge gas such that during deposition the bottom purge flow restricts reactants and/or by-products from depositing below the substrate support  120 . By way of example only, purge gases may include inert gases and/or O 2 , among others. 
     The process chamber  100  includes a chamber body  102  having one or more side walls  104 , a bottom  106 , and a lid  108  disposed on the side walls  104 . The side walls  104 , bottom  106 , and lid  108  define an interior volume  110  of the process chamber  100 . The process chamber  100  includes a gas distribution plate  112  and the substrate support  120 . The region between the substrate support  120  in the raised position  117  ( FIG. 1A ) and the gas distribution plate  112  is defined by the process volume  109 . The gas distribution plate  112  supplies process gases from a process gas source  111  to the process volume  109 . The process chamber  100  may be a plasma chamber, such as a chamber including a plasma source (e.g., a capacitively coupled plasma chamber with a RF-hot gas distribution plate) or a chamber connected to a remote plasma source (RPS). 
     The substrate support  120  is disposed in the interior volume  110 . The substrate support  120  may be formed of a ceramic material, such as aluminum nitride. The substrate support  120  may include an electrostatic chuck, a ceramic body, a heater, a vacuum chuck, a susceptor, or a combination thereof. The substrate support  120  has a substrate supporting surface  122  that receives and supports a substrate  50  during processing. During a clean process, the substrate supporting surface  122  of the substrate support  120  may receive a cover substrate to protect the underlying substrate support  120 . In some embodiments, the cover substrate may comprise a halogen resistant material. The substrate support  120  is coupled to a supporting shaft  121  that is coupled to a lift mechanism  115  below the bottom  106  of the process chamber  100 . A bellows  116  may disposed around the portion of the supporting shaft  121  that is below the bottom  106  of the process chamber to isolate the supporting shaft  121  from the external environment. The lift mechanism  115  is configured to move the substrate support  120  between the raised position  117  (see  FIG. 1A ) and the lowered position  118  (see  FIG. 1B ). The substrate support  120  may be placed in the raised position  117  for processing of the substrate  50 . In the lowered position  118 , a robot or other transfer mechanism may be used to place the substrate  50  in the process chamber  100 , such as placing the substrate  50  on lift pins (not shown) extending above the substrate support  120 . 
     The substrate support  120  further includes a bottom surface  124  and an outer surface  126 . In some embodiments, the outer surface of the substrate support  120  may be angled. The outer angled surface may extend outwardly from the bottom surface  124  to the outer surface  126 . 
     A purge gas may be supplied to the process chamber  100  during processing or cleaning of the process chamber  100 . The purge gas may be supplied from a purge gas source  113  through a purge gas line  114 . In some embodiments, the purge gas line  114  may be coupled to the process chamber  100  through the bellows  116  in order to maintain a positive pressure in the bellows during movement of the substrate support  120  by the lift mechanism  115 . The purge gas may be oxygen, or an inert gas, such as nitrogen or argon. The purge gas helps to prevent process gases from the gas distribution plate  112  from entering portions of the interior volume  110  below the substrate support  120  and depositing on any of the components below the substrate support  120 . Prevention of process gases below the substrate support  120  avoids unnecessary cleaning of the components below the substrate support  120 . Thus, using the purge gas reduces overall clean time and increases throughput of the process chamber  100 . 
     The chamber liner  130  is disposed adjacent the substrate support  120  within the process volume  109 . In some embodiments, the chamber liner  130  can surround the substrate support  120  and the supporting shaft  121 . The chamber liner  130  may be disposed between the substrate support  120  and the side walls  104 . The chamber liner  130  protects the side walls  104  of the process chamber  100  from energized gases during processing and cleaning of the process chamber  100 . The chamber liner  130  includes an annular bottom portion  136 , an a sidewall portion  138 . The annular bottom portion  136  defines an opening  139  in a center region  140  through which the purge gas inlet  119  may allow a purge gas to flow up through the first gap  181 . The sidewall portion  138  extending outward from the annular bottom portion  136 . As shown in  FIGS. 1A and 1B , the sidewall portion  138  extends radially outward from the annular bottom portion  136  toward the substrate support  120 . The chamber liner  130  may be formed of a material which does not react with fluorine. In some embodiments, the chamber liner  130  may comprise a quartz material, an Al 2 O 3  material, a ceramic coated aluminum material, a stainless steel material, or combinations and mixtures thereof. The chamber liner  130 , in some embodiments, may form a continuous surface surrounding (i.e., 360 degrees) at least part of the substrate support  120  and/or at least part of the supporting shaft  121 . In other embodiments, there may be one or more gaps between portions of the chamber liner  130  to accommodate other components, but the chamber liner  130  may still substantially surround the substrate support  120  and the supporting shaft  121 . 
       FIG. 2A  is a side sectional view of the chamber liner  130 , according to one embodiment of the disclosure.  FIG. 2B  is enlarged sectional side sectional view of a portion of the chamber liner  130 , allowing for further details of the chamber liner  130  to be shown. 
     As shown, the sidewall portion  138  of the chamber liner  130  includes a first inner surface  160  and a second inner surface  162 . The first inner surface  160  is adjacent the annular bottom portion  136 . The first inner surface  160  and the second inner surface  162  may be substantially normal relative to a horizontal plane defined by the annular bottom portion  136 . 
     The first inner surface  160  has a first diameter D 1 , as shown in  FIG. 2A . The second inner surface  162  has a second diameter D 2 , as also shown in  FIG. 2A . The second diameter D 2  is less than the first diameter D 1 . For example, in some embodiments, the first diameter D 1  may be between about 13.3 inches and about 14.0 inches, such as about 13.5 inches, while the second diameter D 2  may be between about 12.0 inches and about 13.29 inches, such as about 13.1 inches. The sidewall portion  138  further includes a conical inner surface  164 . The conical inner surface  164  extends between the first inner surface  160  and the second inner surface  162 . The conical inner surface  164  is angled inwardly from the first inner surface  160  to the second inner surface  162 . In some embodiments, the conical inner surface  164  is oriented at an angle A. The angle A may range from about 20 degrees to about 80 degrees from a horizontal plane (e.g., the X-Y plane), such as from about 40 degrees to about 75 degrees from the horizontal plane. In some embodiments, the horizontal plane may be defined by annular bottom portion  136 . The diameter of the conical inner surface  164  may gradually decrease from the first inner surface  160  to the second inner surface  162 . 
     The sidewall portion  138  further includes a first outer surface  168  and a second outer surface  170 . The first outer surface  168  comprises a notch  166  disposed therein. The second outer surface  170  may be angled, and in some embodiments, the second outer surface  170  may be angled inwardly towards the opening  139  in the center region  140 . In some embodiments, the second outer surface is angled inwardly at an angle B between about 20 degrees and about 80 degrees, for example, between about 30 degrees, and about 65 degrees, such as about 38 degrees, relative to a horizontal plane defined by the annular bottom portion  136 . In other embodiments, the second outer surface  170  may be angled substantially parallel to the conical inner surface  164  of the sidewall portion  138 . 
     Benefits of the disclosure include the shielding of sensitive components from halogen damage such that a processing temperature greater than 650 degrees Celsius may be had, thus increasing and improving film quality and properties. 
     Testing was performed and results indicated approximately a 70% reduction in NF 3  faction at or near the edge of the substrate, when a test substrate was utilized to shield the substrate support until the edge of the substrate support was reached. Further testing indicated that, at a processing temperature of about 480 degrees Celsius, approximately 5000-10000 substrates may be processed between cleans, while at a processing temperature of about 550 degrees Celsius, approximately 2000 substrate may be processed between cleans. Moreover, at a processing temperature of about 650 degrees Celsius, approximately 100 substrates may be processed between cleans. 
     To summarize, the embodiments disclosed herein relate to a chamber liner for the high temperature processing of substrates in a processing chamber. The processing chamber utilizes an inert bottom purge flow to shield the substrate support from halogen reactants such that the substrate support may be heated to temperatures greater than about 650 degrees Celsius. The chamber liner controls a flow profile such that during deposition the bottom purge flow restricts reactants and by-products from depositing below the substrate support. During a clean process, the bottom purge flow restricts halogen reactants from contacting the substrate support. As such, the chamber liner includes a conical inner surface angled inwardly to direct purge gases around an edge of the substrate support and to reduce deposition under the substrate support and the on the edge. 
     While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.