Patent Publication Number: US-2023137026-A1

Title: Method and system for selectively removing material at an edge of a substrate

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application Serial No. 63/273,707 filed Oct. 29, 2021 titled METHOD AND SYSTEM FOR SELECTIVELY REMOVING MATERIAL AT AN EDGE OF A SUBSTRATE, the disclosure of which is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF INVENTION 
     The present disclosure generally relates to improved apparatuses and methods for depositing a film and for removing material at an edge of a substrate. 
     BACKGROUND OF THE DISCLOSURE 
     Gas-phase reactors, such as chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), atomic layer deposition (ALD), and the like can be used for a variety of applications, including cleaning, depositing and etching materials on a substrate surface. For example, gas-phase reactors can be used to clean, deposit and/or etch layers on a substrate to form semiconductor devices, flat panel display devices, photovoltaic devices, microelectromechanical systems (MEMS), and the like. 
     After deposition of films using ALD and CVD processes, delamination of the film can occur at an edge or the side of the substrate. The delamination may deleteriously affect subsequent substrate processing and even prevent the substrate from proceeding to the next process—e.g., a lithography process. One resolution to this issue is the use of a bevel etcher to remove the film on the bevel (or edge) of the substrate. In this process, the substrate may be picked up from the deposition process chamber and placed into a different process chamber in which the film at the bevel of the substrate is removed. The removal is facilitated by a confined plasma at the edge of the substrate. However, this process requires the use of two process chambers, reducing throughput, and increasing the time and expense needed to perform the process. 
     Therefore, improved apparatuses and methods that improve the efficiency and reduce the footprint of these processes are desired. 
     Any discussion of problems and solutions set forth in this section has been included in this disclosure solely for the purposes of providing a context for the present disclosure, and should not be taken as an admission that any or all of the discussion was known at the time the invention was made. 
     SUMMARY OF THE DISCLOSURE 
     Exemplary embodiments of this disclosure provide an apparatus and method for selectively etching a bevel/edge of a substrate relative to a center of the substrate. While the ways in which various embodiments of the present disclosure address drawbacks of prior apparatuses and methods are discussed in more detail below, in general, various embodiments of the disclosure provide methods and substrate processing apparatuses for providing an etch gas and generating a plasma at the perimeter of a substrate. 
     In various embodiments of the disclosure, a method of selectively removing a film at the edge of a substrate comprises providing a substrate processing apparatus comprising a susceptor, a gas distribution device, and a flow control ring above the susceptor; providing the substrate on the susceptor; providing a gas distribution device, providing an etch gas below a bottom surface of the substrate; and forming a plasma using the gas distribution device and the susceptor. The gas distribution device may be positioned above the susceptor. The gas distribution device and susceptor may be configured to form a plasma at the perimeter of the substrate. In various embodiments, the etch gas does not remove the film at the center of the substrate to an appreciable extent. In various embodiments, the susceptor comprises an etch gas channel configured to provide the etch gas from below the bottom surface of the substrate toward the top surface of the susceptor and about a perimeter of the substrate. 
     In various embodiments, the plasma is formed between an inner surface of the flow control ring and the perimeter of the susceptor. 
     In various embodiments, the method further comprises modifying a flow rate of the etch gas. The etch gas may comprise, for example, at least one of H 2 , O 2 , CO 2 , NO 2 , NH 3 , He, Ar, N 2 , and CO and mixtures thereof. In some embodiments, the etch gas comprises H 2  and one of Ar and He. 
     In various embodiments, the susceptor comprises an electrostatic chuck. 
     In various embodiments, the method further comprises providing a deposition gas through the gas distribution device while the etch gas is provided. In various embodiments, the deposition gas is provided before the etch gas is provided. In various embodiments, the method comprises providing an inert gas through the gas distribution device while the etch gas is provided. 
     In various embodiments, a substrate processing apparatus comprises a susceptor configured to support a substrate and a gas distribution device above the substrate, wherein the susceptor comprises a channel configured to provide an etch gas from below a bottom of the substrate, and wherein the gas distribution device and the susceptor are configured to form a plasma at a perimeter of the substrate. In various embodiments, the channel extends to the bottom of the susceptor. In various embodiments, the channel is configured to provide the etch gas from below the substrate toward a top surface of the substrate and about the perimeter of the substrate. 
     In various embodiments, the substrate processing apparatus further comprises a flow control ring above the susceptor. In various embodiments, the susceptor comprises an electrostatic chuck. In various embodiments, the susceptor comprises a heater. 
     In various embodiments, a reactor system comprises the substrate processing apparatus of any of the embodiments described herein. 
     These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of certain embodiments having reference to the attached figures; the invention not being limited to any particular embodiment(s) disclosed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       A more complete understanding of exemplary embodiments of the present disclosure can be derived by referring to the detailed description and claims when considered in connection with the following illustrative figures. 
         FIG.  1    illustrates a substrate processing apparatus in accordance with at least one embodiment of the disclosure. 
         FIG.  2    illustrates a film deposition and etching process in accordance with previously known devices. 
         FIGS.  3 A and  3 B  illustrates a film deposition and etching process in accordance with at least one embodiment of the disclosure. 
         FIG.  4    illustrates a substrate processing apparatus in accordance with at least one embodiment of the disclosure. 
         FIG.  5    illustrates a method in accordance with at least one embodiment of the disclosure. 
         FIGS.  6 A and  6 B  illustrate process sequences in accordance with at least one embodiment of the disclosure. 
         FIG.  7    illustrates an exploded view of an exemplary electrostatic chuck electrode 
     
    
    
     It will be appreciated that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of illustrated embodiments of the present disclosure. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Although certain embodiments and examples are disclosed below, it will be understood by those in the art that the invention extends beyond the specifically disclosed embodiments and/or uses described herein and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the invention disclosed should not be limited by the particular disclosed embodiments described below. 
     As used herein, the terms “substrate” may refer to a wafer or any underlying material or materials that may be used to form, or upon which, a device, a circuit, or a film may be formed. Further, the substrate can include various features, such as recesses, lines, and the like formed within or on at least a portion of a layer of the substrate. 
     In some embodiments, the terms “film” and “layer” may be used interchangeably and refer to a layer extending in a direction perpendicular to a thickness direction to cover an entire target or concerned surface, or simply a layer covering a target or concerned surface. In some embodiments, the terms “film” or “layer” refer to a structure having a certain thickness formed on a surface. A film or layer may be constituted by a discrete single film or layer having certain characteristics. Alternatively, a film or layer may be constituted of multiple films or layers, and a boundary between adjacent films or layers may or may not be clear and may or may not be established based on physical, chemical, and/or any other characteristics, formation processes or sequence, and/or functions or purposes of the adjacent films or layers. 
     In some embodiments, “gas” can include material that is a gas at normal temperature and pressure, a vaporized solid and/or a vaporized liquid, and may be constituted by a single gas or a mixture of gases, depending on the context. A gas can include a process gas, an etch gas or other gas that passes through the substrate processing device, such as through a susceptor, a shower plate, a gas distribution device, a gas supply apparatus, an electrode, or the like. A process gas may include a reactant or precursor that takes part in a reaction within a reaction chamber and/or include ambient gas, such as air. An etch gas may include a gas that can etch a portion of a substrate. 
     Further, in this disclosure, any two numbers of a variable can constitute a workable range of the variable, and any ranges indicated may include or exclude the endpoints. Additionally, any values of variables indicated (regardless of whether they are indicated with “about” or not) may refer to precise values or approximate values and include equivalents, and may refer to average, median, representative, majority, etc. in some embodiments. Further, in this disclosure, the terms “including,” “constituted by” and “having” refer independently to “typically or broadly comprising,” “comprising,” “consisting essentially of,” or “consisting of” in some embodiments. In this disclosure, any defined meanings do not necessarily exclude ordinary and customary meanings in some embodiments. Percentages set forth herein are absolute percentages, unless otherwise noted. 
     It shall be understood that the term “comprising” is open ended and does not exclude the presence of other elements or components, unless the context clearly indicates otherwise. The term “comprising” includes the meaning of “consisting of.” The term “consisting of” indicates that no other features or components are present than those mentioned, unless the context indicates otherwise. 
     Turning to the figures,  FIG.  1    illustrates a substrate processing apparatus  100  according to an embodiment of the disclosure. Substrate processing apparatus  100  includes a gas distribution device  130 , a deposition gas feed  180 , a susceptor  110 , an etch gas channel  170 , a substrate stage  150 , and a flow control ring  140 .  FIG.  1    depicts a substrate  160  having a top surface  162  and a bottom surface  164 ; substrate  160  is disposed on the substrate stage  150 . In some embodiments, gas distribution device  130  forms an electrode, and plasma is activated by (e.g., RF) power source  102 . Arrows indicate the direction of gas flow through substrate processing apparatus  100 . A gas provided through deposition gas feed  180  may be a process gas such as a gas including one or more precursors and/or reactants for depositing a film on substrate  160 . The deposition gas feed  180  may also provide an inert (e.g., noble) gas or purge gas. A gas provided through etch gas channel  170  may provide an etch gas to substrate  160 . Due to the position and configuration of etch gas channel  170  below substrate stage  150 , the etch gas is directed to the edge of substrate  160 . In some embodiments, flow control ring  140  also further guides the direction of etch gas to the edge of substrate  160  and out of substrate processing apparatus  100 . In some embodiments, susceptor  110  further includes a heater  532  configured to heat the susceptor  110 . 
       FIG.  2    illustrates a process of depositing a film and etching the substrate at the edge of the film using previous methods and apparatuses. In these processes, an apparatus similar to carbon deposition apparatus  200  is used to deposit a film onto a substrate  230 . Carbon deposition apparatus  200  includes a plasma gas distribution device  220  and power source  202  above a substrate  230 , and a susceptor  210 . In carbon deposition apparatus  200 , a process gas is supplied to substrate  230  through deposition gas feed  240 . Plasma activation forms a deposition plasma  260  that covers the substrate  230  and exits the carbon deposition apparatus  200 . If the resulting film on substrate  230  requires etching at edge of the substrate  230 , the substrate  230  must be transferred to an apparatus similar to carbon bevel etching apparatus  300 , which is configured specifically for etching the edge of the substrate  230 . Carbon bevel etching apparatus  300  includes a susceptor  310 , a plasma electrode  320  and power source  302  below substrate  230 , and a gas supply apparatus  340  above substrate  230  through which etch gas is supplied to substrate  230 . An etch gas feed  350  is configured to direct gas flow to the edge of substrate  230 . Plasma electrode  320  is positioned below substrate  230  at the edge of susceptor  310  in order to generate an etching plasma  360  only at the edge of substrate  230 . 
     In contrast, a process of depositing a film and etching the substrate at the edge of the film according to embodiments described herein is illustrated at  FIG.  3   . As shown in  FIGS.  1  and  3   , substrate processing apparatus  100  may be configured to provide etch gas through etch gas channel  170  below substrate  160 , and to a generate deposition plasma  190  from gas distribution device  130  above substrate  160 .  FIG.  3 A  illustrates formation of a deposition plasma  190  in the substrate processing apparatus  100 . In some embodiments, the deposition plasma  190  is activated by RF (e.g., 13.56 MHz) power by CCP type power source  102 .  FIG.  3 B  illustrates formation of an etching plasma  108  within the same substrate processing apparatus  100 . Due to the position of etch gas channel  170  and flow control ring  140 , generation of etching plasma  108  by electrode  130  may be focused at the edge of substrate  160 , while a gas mixture forms a diluted plasma  112  at the center of substrate  160 , which does not etch the film or material on substrate  160 . The configuration of substrate processing apparatus  100  eliminates the need to transfer the substrate  160  to a separate apparatus for etching, thereby reducing the need for multiple tools to achieve the deposition and etching processes. 
       FIG.  4    illustrates a substrate processing apparatus  400  according to another embodiment of the disclosure. Substrate processing apparatus  400  includes a gas distribution device  430 , a deposition gas feed  480 , a susceptor  410 , an etch gas channel  470 , a substrate stage  450 , and a flow control ring  440 . In some embodiments, susceptor  410  is configured as an electrostatic chuck, including an electrostatic chuck electrode  460  embedded within susceptor  410 , and a gas is provided to a bottom surface of substrate  462  through center gas feed  490 . In some embodiments, the gas provided through center gas feed  490  is a temperature control gas (e.g. helium).  FIG.  7    illustrates an exploded view of an exemplary electrostatic chuck electrode  460 , including a top plate  710 , an insulator  720 , and a bottom plate  730 . In some embodiments, insulator  720  includes a ceramic material, and top plate  710  and bottom plate  730  include a metal material. In the illustrated embodiment, gas provided through center gas feed  490  is distributed to a channel  740  in insulator  720 . From channel  740 , gas is then distributed through gas holes  750  in top plate  710  to reach the perimeter of substrate  462 . In  FIG.  7   , gas holes  750  are depicted in a portion of top plate  710  for simplicity. Gas holes  750  may be distributed around the entire circumference of top plate  710 . The electrostatic chuck electrode  460  is powered by direct current lines  760 . 
       FIG.  5    illustrates a method  500  for selectively removing a film at the edge of a substrate according to embodiments of the disclosure. Method  500  can be performed using process sequence  600 . Method  500  includes the steps of providing a substrate processing apparatus ( 510 ), providing a substrate on the susceptor ( 520 ), providing an etch gas ( 530 ) below the susceptor, and forming a plasma using the gas distribution device and the susceptor ( 540 ). In some embodiments, the etch gas comprises at least one of a hydrogen-containing gas, an oxidant, a nitrogen-containing gas, a nitrogen and oxygen-containing gas, a nitrogen and hydrogen-containing gas, a noble gas, or mixtures thereof. By way of examples, the etch gas can include one or more of H 2 , O 2 , CO 2 , NO 2 , NH 3 , He, Ar, N 2 , and CO in any combination. In some embodiments, the etch gas comprises Ar and H 2 . In some embodiments, the etch gas comprises He and H 2 . 
     The steps of method  500  may be performed using substrate processing apparatus  100  or  400  in accordance with embodiments of the disclosure. In some embodiments, the gas distribution device is above the susceptor. In some embodiments, the gas distribution device and susceptor are configured to form a plasma at a perimeter of the substrate. In some embodiments, the substrate processing apparatus comprises a flow control ring above the susceptor. In some embodiments, the plasma is formed between an inner surface of the flow control ring and the perimeter of the susceptor. In preferred embodiments, the etch gas does not remove the film at the center of the substrate—to an appreciable extent. In preferred embodiments, the susceptor comprises an etch gas channel configured to provide the etch gas from below the bottom surface of the substrate toward the top surface of the susceptor and about a perimeter of the substrate. 
     In some embodiments, a flow rate of the etch gas is manipulated to adjust an area of the substrate to be etched. 
     In some embodiments, method  500  further comprises providing a deposition gas ( 550 ) through the gas distribution device while the etch gas is provided. In some embodiments, method  500  comprises providing a deposition gas ( 550 ) through the gas distribution device before the etch gas is provided. In some embodiments, method  500  comprises providing an inert gas ( 560 ) through the gas distribution device. In some embodiments, the steps of providing deposition gas ( 550 ) and providing inert gas ( 560 ) overlap with steps  530 - 540 . 
     Exemplary deposition gases include one or more carbon containing precursors. In some embodiments, the deposition gas includes a precursor having the formula C x H y O 2 , where x is a natural number ranging from 2 to 10, y is a natural number ranging from 2 to 30, and z is a natural number ranging from 0 to 5. Exemplary inert gases include noble gases (e.g. Ar, He, Xe, Kr). 
       FIGS.  6 A and  6 B  illustrate exemplary process sequences  600  of and  650  according to embodiments of the disclosure.  FIG.  6 A  illustrates a process sequence  600  in which film deposition ( 610 ) and film etching ( 620 ) are performed simultaneously. In some embodiments, deposition gas  612  comprises carbon. In some embodiments, deposition gas  612  comprises helium. In some embodiments, etch gas  614  comprises H 2 . In some embodiments, etch gas  614  comprises helium. Process sequence step  610  can be the same or similar to method steps  560  and/or  570 ; and process sequence step  620  can be the same or similar to method step  530 . 
       FIG.  6 B  illustrates a process sequence  650  in which film etching ( 640 ) is performed after film deposition ( 630 ) (post-etching). In some embodiments, deposition gas  616  comprises carbon. In some embodiments, deposition gas  616  comprises helium. In some embodiments, when deposition gas  616  is turned off, inert gas  618  and etch gas  622  are turned on. In some embodiments, inert gas comprises helium. In some embodiments, etch gas  622  comprises H 2 . In some embodiments, etch gas  622  comprises helium. Process sequence step  630  can be the same or similar to method steps  550  and/or  560 ; and process sequence step  640  can be the same or similar to method step  530 . 
     The example embodiments of the disclosure described above do not limit the scope of the invention since these embodiments are merely examples of the embodiments of the invention. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the disclosure, in addition to those shown and described herein, such as alternative useful combinations of the elements described, may become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims.