Patent Publication Number: US-2023162948-A1

Title: Multi-antenna unit for large area inductively coupled plasma processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of U.S. provisional patent application Ser. No. 63/282,341, filed Nov. 23, 2021, which is herein incorporated by reference. 
    
    
     BACKGROUND 
     Field 
     Embodiments of the present disclosure generally relate to process chambers, such as high density plasma (HDP) chambers used in semiconductor manufacturing. More particularly, embodiments of the present disclosure relate to antenna configurations for process chambers 
     Description of the Related Art 
     In the manufacture of solar panels or flat panel displays, many processes are employed to deposit thin films on substrates, such as semiconductor substrates, solar panel substrates, and liquid crystal display (LCD) and/or organic light emitting diode (OLED) substrates, to form electronic devices thereon. The deposition is generally accomplished by introducing a precursor gas into a chamber having a substrate disposed on a temperature controlled substrate support. The precursor gas is typically directed through a gas distribution assembly disposed above the substrate support. The precursor gas in the chamber is energized (e.g., excited) into a plasma by applying a single or array of radio frequency (RF) antennas inductively coupled to the precursor gas to form the plasma. The excited gas reacts to form a layer of material on a surface of the substrate that is positioned on the temperature controlled substrate support. 
     The size of the substrates for forming the electronic devices exceeds one square meter in surface area. Uniformity in film thickness across these substrates is difficult to achieve. Power applied to generate plasma within the process chamber can generate eddy currents which negatively affect plasma uniformity, and thus, deposition uniformity, and may also create other hardware issues such as, but not limited to, arcing and RF power loss. 
     Therefore, there is a need for methods and apparatuses for generating more uniform plasmas and/or reducing other hardware issues. 
     SUMMARY 
     The present disclosure generally relates to inductive coupler arrangements for use in processing chambers, such as those suitable for use in semiconductor manufacturing. The present disclosure also generally relates to lids and processing chambers having inductive couplers. 
     In one example, a lid suitable for use in a semiconductor processing chamber. The lid includes a plurality of dielectric windows coupled to a perforated faceplate. The lid also includes a plurality of support members coupled to the perforated faceplate and positioned between adjacent dielectric windows. The lid further includes a plurality inductive couplers comprising a first subset of inductive couplers and a second subset of inductive couplers. Each inductive coupler of the first subset of inductive couplers includes a first lower portion, a second lower portion, and a bridge. The bridge is disposed over at least one of the plurality of support members. The first lower portion is positioned on a first dielectric window of the plurality of dielectric windows. The second lower portion is positioned on a second dielectric window of the plurality of dielectric windows. The second dielectric window is adjacent to the first dielectric window. 
     In another example, a lid suitable for use in a semiconductor processing chamber. The lid includes a plurality of dielectric windows coupled to a perforated faceplate, and the plurality of dielectric windows have a first subset of dielectric windows and a second subset of dielectric windows. The lid further includes a plurality of support members coupled to the perforated faceplate and positioned between adjacent dielectric windows. The lid includes a plurality of inductive couplers comprising a first subset of inductive couplers and a second subset of inductive couplers. The first subset of inductive couplers are non-planar. The second subset of inductive couplers are planar. The first subset of dielectric windows have a portion of two inductive couplers of the first subset of inductive couplers positioned thereon. The second subset of dielectric windows have a portion of one inductive coupler of the first subset of inductive couplers and one inductive coupler of the second subset of inductive couplers positioned thereon. 
     In yet another example, a lid suitable for use in a semiconductor processing chamber. The lid includes a plurality of dielectric windows coupled to a perforated faceplate, where the plurality of dielectric windows includes a first subset of dielectric windows and a second subset of dielectric windows. The lid further includes a plurality of support members coupled to the perforated faceplate and positioned between adjacent dielectric windows. The lid includes a first subset of inductive couplers, where the inductive couplers include a first lower portion, a second lower portion, and a bridge. The lid further includes a second subset of inductive couplers, where the second subset of inductive couplers are planar. The first subset of dielectric windows each has a portion of two inductive couplers of the first subset of inductive couplers positioned thereon. The second subset of dielectric windows each has a portion of one inductive coupler of the first subset of inductive couplers and one inductive coupler of the second subset of inductive couplers positioned thereon. The bridge is disposed over at least one of the plurality of support members. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present 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 exemplary embodiments and are therefore not to be considered limiting of scope, as the disclosure may admit to other equally effective embodiments. 
         FIG.  1    is a schematic cross-sectional front view of a chamber according to an embodiment. 
         FIG.  2    is a cross-sectional perspective side view of a portion of a lid assembly according to an embodiment. 
         FIGS.  3 A and  3 B  illustrate a schematic plan view of an inductive coupler arrangement of a lid according to one embodiment. 
         FIG.  4    illustrates a schematic plan view of an inductive coupler arrangement of a lid according to another embodiment. 
         FIG.  5    illustrates a schematic plan view of an inductive coupler arrangement of a lid according to another embodiment. 
         FIG.  6    illustrates a schematic plan view of an inductive coupler arrangement of a lid according to another embodiment. 
     
    
    
     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 and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. 
     DETAILED DESCRIPTION 
     The present disclosure generally relates to inductive coupler arrangements for use in processing chambers, such as those suitable for use in semiconductor manufacturing. The present disclosure also generally relates to lids and processing chambers having inductive couplers. The inductive couplers of the present disclosure are arranged with respect to one another so that eddy currents generated by the adjacent inductive couplers are reduced, thus improving plasma uniformity. 
     In one example, a lid suitable for use in a semiconductor processing chamber comprises a plurality of dielectric windows, a plurality of support members positioned between adjacent dielectric windows, and a plurality inductive couplers positioned adjacent the dielectric window. Each dielectric window of the plurality of dielectric windows has at least a portion of two of the inductive couplers of the plurality of the inductive couplers positioned thereover. 
       FIG.  1    is a schematic cross sectional side view of processing chamber  100 , according to one embodiment of the present disclosure. An exemplary substrate  102  is shown on a substrate surface  120  within a chamber body  104 . The substrate  102  may be, for example, a large area substrate having a surface area great than 1 square meter. The processing chamber  100  also includes a lid assembly  106 , a bottom  118  disposed opposite the lid assembly  106 , and a pedestal or substrate support assembly  108  disposed between the lid assembly  106  and the bottom  118 . The lid assembly  106  is disposed at an upper end of the chamber body  104 , and the substrate support assembly  108  is at least partially disposed within the chamber body  104 . The substrate support assembly  108  is coupled to a shaft  110 . The shaft  110  is coupled to a drive  112  that moves the substrate support assembly  108  vertically (in the Z direction) within the chamber body  104 . The substrate support assembly  108  of the processing chamber  100  shown in  FIG.  1    is in a processing position. However, the substrate support assembly  108  may be lowered in the Z direction to a position adjacent to a transfer port  114 . 
     The lid assembly  106  includes a backing plate  122  that rests on the chamber body  104 . The lid assembly  106  also includes a gas distribution assembly or showerhead  124 . The showerhead  124  delivers process gases from a gas source to a processing region  126  between the showerhead  124  and the substrate  102 . The showerhead  124  is also coupled to a cleaning gas source that provides cleaning gases, such as fluorine, chlorine, or oxygen containing gases, to the processing region  126 . 
     The showerhead  124  also functions as a plasma source. To function as the plasma source, the showerhead  124  includes one or more inductively coupled plasma generating components, or inductive couplers  130   a ,  130   b  (e.g., antennas or coils). Each of the one or more inductive couplers  130   a ,  130   b  are coupled across a power source and ground  133 . Although  FIG.  1    depicts each of the inductive couplers  130   a ,  130   b  connected to the power source and ground  133  in parallel to facilitate control and tunability, a connection in series is also contemplated. In some embodiments, ground  133  is a capacitor or grounded through a capacitor. The showerhead  124  also includes a face plate  132  that comprises a plurality of discrete perforated tiles  134 . The power source includes a match circuit or a tuning capability for adjusting electrical characteristics of the inductive couplers. 
     Each of the perforated tiles  134  are supported by a plurality of support members  136 . Each of the one or more inductive couplers  130   a ,  130   b  or portions of the one or more inductive couplers are positioned on or over a respective dielectric window  138 . A plurality of gas volumes  140  (three are shown) are defined by surfaces of the dielectric windows  138 , the perforated tiles  134  and the support members  136 . Each of the one or more inductive couplers  130   a,b  is configured to create an electromagnetic field that energizes the process gases into a plasma as gas is flowing into the gas volumes  140  and into the chamber volume therebelow through the adjacent perforated tile  134 . In some embodiments which may be combined with other embodiments, process gases from the gas source are provided to each of the gas volumes  140  via conduits in the support members  136 . The volume or flow rate of gas(es) entering and leaving the showerhead are controlled in different zones of the showerhead  124 . Zone control of processing gases is provided by a plurality of flow controllers, such as mass flow controllers  142 ,  143  and  144  illustrated in  FIG.  1   . When chamber cleaning is required, cleaning gases from a cleaning gas source is flowed to each of the gas volumes  140  and thence into the processing volume  140  within which the cleaning gases are energized into ions, radicals, or both. The energized cleaning gases flow through the perforated tiles  134  and into the processing region  126  in order to clean chamber components. 
       FIG.  2    is an enlarged cross-sectional side view of a portion of the lid assembly  106  of  FIG.  1   . The perforated tiles  134  include a plurality of openings  218  extending therethrough. Each of the plurality of openings  218  allow gases to flow from the gas volumes  140  into the processing region  126 , at predetermined flow rates due to the diameter of the openings  218 . A mounting portion  225  surrounds the sides of adjacent perforated tiles  134  at an interface of adjacent perforated tiles  134 . The mounting portion  225  includes a ledge or shelf that supports a portion of the perimeter or an edge of the perforated tiles  134 . The mounting portion  225  is fastened to support members  136  by a fastener, such as a bolt or screw. Each support member  136  includes a ledge or shelf that supports a portion of the perimeter or an edge of the dielectric window  138 . 
     The use of the multiple dielectric windows  138  provides a physical barrier between the gas volume  140  and processing region  126 , without imposing large stresses on the windows which would otherwise occur if fewer/larger dielectric windows were utilized. In some embodiments, during processing, the gas volumes  140  have a pressure of about 10 mTorr to about 3 Torr. 
     Materials for the showerhead  124  are chosen based on one or more of electrical characteristics, strength and chemical stability. The inductive couplers are made of an electrically conductive material, such as copper or aluminum. The backing plate  122  and the support members  136  are made of a material that is able to support the weight of the supported components and atmospheric pressure load, which may include a metal or other similar material, such as aluminum or aluminum alloy, or steel. The backing plate  122  and the support members  136  can be made of a non-magnetic material (e.g., non-paramagnetic or non-ferromagnetic material), such as aluminum or an alloy thereof. The perforated tiles  134  are made of a ceramic material, such as quartz, alumina or other similar material. The dielectric windows  138  are made of a quartz, alumina or sapphire. In some embodiments which may be combined with other embodiments, the dielectric windows  138  include copper, silver, aluminum, tungsten, molybdenum, titanium, combinations thereof, or alloys thereof. 
     The lid assembly  106  includes two different inductive couplers  130   a , and  130   b . The inductive couplers  130   a  are planar coils (e.g., a spiral coil disposed in a plane) and positioned entirely above a single dielectric window  138 . The inductive couplers  130   b  are bridged coils (e.g., non-planar coils) which include a lower portion  280  and a bridge  281 . The bridge  281  is disposed over a respective support member  136  such the inductive coupler  130   b  is positioned above adjacent dielectric windows  138 . In one example, the footprint of the inductive coupler  130   a  is about half the footprint of the inductive couple  130   b , such as about 70 percent to about 30 percent, for example about 60 percent to about 40 percent or about 55 percent to about 45 percent. In another embodiment, which can be combined with embodiments herein, it is contemplated that inductive coupler  130   a  may have a bridged configuration similar to the inductive coupler  130   b , even though the inductive coupler  130   a  does not span a support member  136 . In such a configuration, the inductive coupler  130   a  still has a reduced footprint relative to the inductive coupler  130   b.    
       FIGS.  3 A and  3 B  illustrate a schematic plan view of an inductive coupler arrangement of a lid  106  according to one embodiment. The lid  106  includes a plurality of dielectric windows  138  (six are shown) in a 2×3 array, and a plurality of inductive couplers  130   a  (four are shown) and inductive couplers  130   b  (four are shown). To facilitate explanation, inductive couplers  130   a  are individually labeled  130   a   1 - 130   a   4  (collectively reference to  130   a ), and similarly, inductive couplers  130   b  are individually labeled  130   b   1 - 130   b   4  (collectively referred to as  130   b ). 
     Each of the inductive couplers  130   a  are positioned adjacent laterally outward edges of the lid  106  and entirely over a single respective dielectric window  138 . Each of the inductive couplers  130   b  are positioned inward of the inductive couplers  130   a . Each inductive coupler  130   b  is positioned over two dielectric windows. In the illustrated configuration, each inductive coupler  130   a  also (partially) shares a dielectric window  138  with inductive coupler  130   b . Similarly, each inductive coupler  130   b  also shares a dielectric window with another inductive coupler  130   b.    
     With reference to both  FIGS.  3 A and  3 B , the inductive couplers  130   a  and inductive couplers  130   b  are positioned such that adjacent inductive couplers generate magnetic fields in opposite directions. For example, inductive couplers  130   a   1 ,  130   b   2 ,  130   b   3 , and  130   a   4  all generate magnetic fields which extend in the z-direction (e.g., out of plane of the page and denoted by symbol  195 ), while inductive couplers  130   b   1 ,  130   a   2 ,  130   a   3 , and  130   b   4  all generate magnetic fields which extend in the negative z-direction (e.g. into the page and denoted by symbol  196 ). Arrows  190  of each inductive coupler  130   a ,  130   b  are illustrated to show the direction of current flow at the time of processing, which generates a corresponding magnetic field according to the “right hand rule.” 
     As a result of current provided to each inductive coupler  130   a ,  130   b , and the magnetic field generated thereby, eddy currents, indicated by arrows  192 , are generated with the lid  106  of the process chamber. In conventional systems, generated eddy currents result in plasma non-uniformities, particularly at the edges of the lid  106  and/or at a center of the lid  106  due to inductive coupler arrangement relative to a respective support member  136  of each dielectric window  138  (which tends to accumulate eddy currents). However, the inductive coupler arrangement of the present disclosure effectively reduces eddy currents within the lid  106  due to the positioning thereof relative to the support members  136  at the dielectric window  138  perimeter. In particular, the inductive couplers  130   a ,  130   b  are positioned such that eddy currents generated around each dielectric window  138  (and the support members  136  surround each dielectric window  138 ) are in opposite directions, and thus substantially cancel one another out. To accomplish this, each dielectric window includes thereover at least portions of multiple (e.g., two) inductive couplers, which generate magnetic fields in opposite directions. The generation of magnetic fields in opposite directions results in eddy currents in opposite directions which cancel one another out. Because the eddy currents are cancelled out, eddy current effects on the plasma are reduced, and thus, plasma uniformity is increased. 
       FIG.  4    illustrates a schematic plan view of an inductive coupler arrangement of a lid  406  according to another embodiment. The lid  406  is similar to the lid  106 , but includes four dielectric windows  138 . Each dielectric window  138  has positioned thereover two (or portions thereof) inductive couplers, each of which generating magnetic fields in opposite directions. For example, each dielectric window  138  includes an inductive coupler  130   a  thereover, as well as a portion of an inductive coupler  130   b  thereover. The magnetic field directions of each respective inductive coupler  130   a ,  130   b  are illustrated by symbols  195 ,  196 . The magnetic field directions indicated by symbols  195 ,  196  result in a reduction of eddy currents, improving plasma uniformity. 
       FIG.  5    illustrates a schematic plan view of an inductive coupler arrangement of a lid  506  according to another embodiment. The lid  506  is similar to the lid  406 , but includes 15 dielectric windows  138  in a 3×5 array. Each dielectric window  138  has positioned thereover two (or portions thereof) inductive couplers, each of which generating magnetic fields in opposite directions. For example, each dielectric window  138  includes an inductive coupler  130   a  thereover, as well as a portion of an inductive coupler  130   b  thereover. The magnetic field directions of each respective inductive coupler  130   a ,  130   b  are illustrated by symbols  195 ,  196 . The magnetic field directions indicated by symbols  195 ,  196  result in a reduction of eddy currents, improving plasma uniformity. As illustrated by the lid  506 , the inductive couplers  130   a ,  130   b  can be arranged in different orientations, and can be scaled to accommodate arrays of desired dimensions. 
       FIG.  6    illustrates a schematic plan view of an inductive coupler arrangement of a lid  606  according to another embodiment. The lid  606  is similar to the lid  506 , but includes 30 dielectric windows  138  in a 5×6 array. Each dielectric window  138  has positioned thereover two (or portions thereof) inductive couplers, each of which generating magnetic fields in opposite directions. For example, each dielectric window  138  along the laterally outward edges includes an inductive coupler  130   a  thereover, as well as a portion of an inductive coupler  130   b  thereover. Interior dielectric windows  138  include a portion of a first inductive coupler  130   b  and a portion of a second inductive coupler  130   b  thereover. The magnetic field directions of each respective inductive coupler  130   a ,  130   b  are illustrated by symbols  195 ,  196 . The magnetic field directions indicated by symbols  195 ,  196  result in a reduction of eddy currents, improving plasma uniformity. As illustrated by the lid  606 , the inductive couplers  130   a ,  130   b  can be arranged in different orientations, and can be scaled to accommodate arrays of desired dimensions. 
     Aspects of the present disclosure provide for reduced eddy current effects during processing, thus improving plasma uniformity and increasing average plasma density since the effect of eddy currents on the plasma is reduced. In addition, the reduction of eddy currents provided by the disclosed embodiments also reduces undesired and/or adverse effects on chamber components which otherwise in occur in conventional ICP chambers. For example, the reduction in eddy currents in support members surrounding dielectric windows—particularly those adjacent chamber components such as the chamber wall or body—results in less likelihood of arcing occurring between the support member and the adjacent chamber component. The reducing in arcing improves hardware longevity and reduces particle contamination. Moreover, the reduction in eddy currents facilitates improvements in RF power loss and temperature uniformity within the process chamber (thus promoting process uniformity), and also reduces the cooling requirements of the process chamber. For example, due to the reduced eddy currents in the support members, resistive heating of the support members is reduced, lowering the cooling requirements of the process chamber and facilitating temperature uniformity. 
     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.