Patent Publication Number: US-2023163019-A1

Title: Substrate lift mechanism and reactor including same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of, and claims priority to and the benefit of, U.S. patent application Ser. No. 16/944,271, filed Jul. 31, 2020 and entitled “SUBSTRATE LIFT MECHANISM AND REACTOR INCLUDING SAME,” which is a Divisional of, and claims priority to and the benefit of, U.S. patent application Ser. No. 15/672,096, filed Aug. 8, 2017 and entitled “SUBSTRATE LIFT MECHANISM AND REACTOR INCLUDING SAME,” which is hereby incorporated by reference herein. 
    
    
     FIELD OF INVENTION 
     The disclosure generally relates to apparatus for gas-phase processes. More particularly, exemplary embodiments of the present disclosure relate to a reactor including a common substrate transfer and processing region and to a substrate lift mechanism suitable for use therein. 
     BACKGROUND OF THE DISCLOSURE 
     Gas-phase reactors for processing substrates, such as semiconductor wafers, often include a susceptor within a reaction chamber. During processing, one or more substrates are placed within the reaction chamber and onto the susceptor using a robotic arm. After processing, the substrate(s) are removed from the surface of the susceptor and through an opening in the reaction chamber using the robotic arm. 
     Often, it is desirable to maintain a relatively small reaction space or region within the reaction chamber. The relatively small reaction space allows for more-efficient substrate processing. For example, a smaller amount of reactants can be used when processing substrates in a relatively small reaction space—compared to a larger reaction space and/or an amount of time to process substrates using the relatively small reaction space can be less than the amount of time to process substrates in the larger reaction space. To allow for a relatively small reaction space within a reaction chamber, while allowing placement of substrates onto the susceptor and removal of the substrates from the susceptor, a reaction chamber often includes a separate wafer transfer region that includes the opening within the reaction chamber to allow placement on and removal of the substrates from the susceptor. 
     During the substrate transfer process, lift pins, which extend through a vertical width of the susceptor and beyond, are sometimes used to facilitate placement and removal of the substrate on and from the surface of the susceptor. In such cases, a substrate can be placed onto the susceptor by placing (lowering) the susceptor to be within the substrate transfer region of the reaction chamber, causing the lift pins to rise above the surface of the susceptor, placing the substrate onto the lift pins, and lowering the lift pins, such that the substrate rests on the susceptor. The susceptor and the substrate can then be moved (raised) to a processing position, such that the substrate is within the reaction region of the reaction chamber. 
     Although such techniques work relatively well to place substrates within and remove substrates from a reaction space within the reactor, mechanisms to move the susceptor and the lift pins are relatively complex. In addition, reactors employing such techniques can exhibit undesired gas flow between the reaction region and the substrate transfer region—especially during substrate processing. The undesired gas flow can lead to deposition and/or corrosion of the reactor within the substrate transfer region. Furthermore, the volumes of such reactors are relatively large to accommodate both the processing/reaction region and the substrate transfer region of the reaction chamber. In addition, the multi-step process of moving the susceptor to a transfer region and moving the lift pins is a relatively time consuming. Accordingly, improved mechanisms and techniques for transferring and processing substrates are desired. 
     SUMMARY OF THE DISCLOSURE 
     Various embodiments of the present disclosure provide an improved method and apparatus for processing and transferring substrates. As set forth in more detail below, various systems and methods provide a reactor and/or use a method that can process substrates within a region and transfer substrates to/from the same region within a reactor. In other words, the reactor can include a reaction chamber including a common processing and transfer region. Accordingly, the overall reactor volume can be relatively small, the reactor can be less complex, more reliable, less expensive, and easier to maintain and/or process substrates in a reduced amount of time and/or in a less expensive manner. 
     In accordance with at least one exemplary embodiment of the disclosure, a reactor, which includes a common substrate processing and transfer region, includes a reaction chamber comprising a reaction region, a susceptor having a top surface within the reaction region, and a substrate lift mechanism. The substrate lift mechanism can include at least one lift pin, a lift pin support member that engages to (e.g., removably) couple to the at least one pin, and a movable shaft coupled to the lift pin support member. The substrate lift mechanism causes the at least one lift pin to extend above the susceptor surface. In accordance with various aspects of these embodiments, the moveable shaft moves in a vertical direction. The distance that the movable shaft and the lift pins move during a substrate transfer process can range from about 5 mm to about 25 mm, about 10 mm to about 20 mm, or be about 17 mm. In accordance with further aspects of these embodiments, the susceptor includes a center region and a peripheral region. A width of the center region can be greater than a width of the peripheral region. Such a design can facilitate forming the susceptor with a relatively small peripheral width, which in turn can facilitate use of the common region for both substrate processing and transfer. The reactor can further include a rotatable shaft and a susceptor support coupled to the rotatable shaft. The susceptor is coupled to the susceptor support, such that rotational movement of the rotatable shaft is translated to the susceptor. In accordance with various examples of these embodiments, an opening within the reaction chamber, to transfer substrates into and out of the reaction chamber, resides above a top surface of the susceptor when the susceptor is in a processing position. 
     In accordance with at least one other embodiment of the disclosure, a substrate support assembly includes a susceptor, a susceptor support coupled to the susceptor, a rotatable shaft coupled to the susceptor support, a lift pin support member, one or more lift pins coupled to the lift pin support member, a moveable shaft coupled to the lift pin support member, a lift pin mechanism to cause the moveable shaft to move in a vertical direction, and a susceptor rotation mechanism that causes the susceptor to rotate during substrate processing. The substrate support assembly can be configured, such that the susceptor does not move in a vertical direction during a substrate transfer process. In accordance with various aspects of these embodiments, the susceptor support includes a plurality of susceptor support arms and one or more susceptor support structures coupled to each susceptor support arm. The susceptor arm(s) can include an aperture to receive one of the one or more lift pins. The susceptor can be the same or similar to the susceptor described above and elsewhere in this specification. 
     In accordance with at least one further exemplary embodiment of the disclosure, a method of transferring and processing a substrate includes the steps of providing a reactor comprising a common region for substrate processing and substrate transfer, providing a substrate support assembly, such as the assembly described above and elsewhere in this specification, providing a substrate to the common region, moving the lift pins in a downward position to place the substrate in a processing position, processing the substrate, moving the lift pins in an upward position, and removing the substrate from the common region. The method can include removing the substrate from the common region through an opening that is located above a top surface of the susceptor—e.g., when the susceptor is in a processing position. 
     Both the foregoing summary and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure or the claimed invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       A more complete understanding of the embodiments of the present disclosure may be derived by referring to the detailed description and claims when considered in connection with the following illustrative figures. 
         FIG.  1    illustrates a reactor in accordance with exemplary embodiments of the disclosure. 
         FIG.  2    illustrates components of a substrate support assembly in accordance with additional embodiments of the disclosure. 
         FIGS.  3 - 5    illustrate a lift/rotate mechanism in accordance with exemplary embodiments of the disclosure. 
     
    
    
     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 to improve understanding of illustrated embodiments of the present disclosure. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION 
     The description of exemplary embodiments of methods and apparatus provided below is merely exemplary and is intended for purposes of illustration only; the following description is not intended to limit the scope of the disclosure or the claims. Moreover, recitation of multiple embodiments having stated features is not intended to exclude other embodiments having additional features or other embodiments incorporating different combinations of the stated features. 
     Any ranges indicated in this disclosure 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, or the like. 
     Turning now to  FIG.  1   , a reactor  100  in accordance with at least one embodiment of the disclosure is illustrated. Reactor  100  includes a reaction chamber  102  including a reaction region  104  and a substrate lift mechanism  106 . As described in more detail below, during a substrate transfer operation, substrate lift mechanism  106  facilitates placement of a substrate  116  onto a top surface  122  of a susceptor  118  within reaction region  104  to allow removal of substrate  116  through an opening  120  of reaction chamber  102 . 
     Reaction chamber  102  can be formed of, for example, quartz, and can be formed as a unitary piece, such as a tube. By way of example, reaction region  104  within reaction chamber  102  can have a rectangular cross section having a width of about 350 mm to about 450 mm (or be about ˜420 mm), a length of about 400 mm to about 800 mm (or be about ˜760 mm), and a height of about 20 mm to about 40 mm (or be about ˜30 mm). As noted above, reaction chamber  102  includes an opening  120  that resides above top surface  122  of susceptor  118  (e.g., when surface  122  is in a processing position). 
     Reaction chamber  102  can be suitable for a variety of applications, such as film (e.g., epitaxial) deposition processes, etch processes, cleaning processing, and the like. Further, reactor  100  can be a standalone reactor or form part of a cluster tool that may include similar or different reaction chambers. 
     Substrate lift mechanism  106  includes at least one lift pin  108 ,  110 , a lift pin support member  112  that can engage with and couple to the at least one pin  108 ,  110 , and a movable shaft  114  mechanically coupled to the lift pin support member. During a substrate transfer process, substrate lift mechanism  106  causes the at least one lift pin  108 ,  110  to be raised or lowered to allow placement of substrate  116  onto surface  122  and/or removal of substrate  116  from surface  122 . 
     Lift pins  108 ,  110  can be formed of any suitable material. For example, lift pins  108 ,  110  can be formed of silicon carbide (SiC), SiC-coated graphite, quartz, or glassy carbon. Although two lift pins  108 ,  110  are shown in  FIG.  1   , reactor  100  includes three (e.g., equally) spaced apart lift pins. Reactors in accordance with other embodiments of the disclosure can include any suitable number of lift pins and generally include three or three or more lift pins. A length L of lift pins  108 ,  110  can vary according to application. Generally a length of lift pins  108 ,  110  allows lift pins  108 ,  110  to extend through a width W of susceptor  118  and above the susceptor top surface  122 —for example, when receiving a substrate  116  from a robotic arm (not illustrated) or presenting substrate  116  to be received by the robotic arm. 
     In accordance with some embodiments of the disclosure, lift pins  108 ,  110  have a length L of about 20 to about 40 mm or about 30 mm. This is a significantly shorter length than typical lift pins and allows processing and substrate transfer within a common region, namely reaction region  104 . Lift pins  108 ,  110  can include a beveled section  124  that is received within a portion of susceptor  118 . Beveled section  124  allows lift pins  108 ,  110  to be received within a via  126  within susceptor  118  and to be retained at a desired level (e.g., a top surface of lift pins can be about planar with surface  122  or reside just (e.g., a few mm or less) below surface  122 . This allows susceptor  118  to retain lift pins  108 ,  110  when, for example, lift pin support member  112  is not engaged with lift pins  108 ,  110 . A top surface  128 ,  130  of lift pins  108 ,  110  can have a diameter of about 3 to about 6 mm, or about 4 mm. Top surface  128 ,  130  can be polished to a smooth finish (e.g., a roughness average of about 0.05 to 0.2 μm or less) to prevent or mitigate surface damage to substrate  116  during a transfer process. 
     Lift pin support member  112  engages with lift pins  108 ,  110  and moveable shaft  114 . In the illustrated example, lift pin support member  112  removably engages with lift pins  108 ,  110  and is coupled to moveable shaft  114 . This allows movable shaft  114  to move only in a vertical direction (and not rotate), while allowing susceptor  118  to rotate—e.g., during substrate processing, as described in more detail below. Lift pin support member  112  can be formed of, for example, SiC-coated graphite, quartz, or glassy carbon. 
     As illustrated in more detail in  FIG.  2   , lift pin support member  112  includes a plurality of lift pin arms  202 ,  204 . Although two lift pin support arms are illustrated in  FIG.  2   , the illustrated lift pin support member includes three lift pin support arms. Each lift pin support arm  202 ,  204  includes a first end  206 ,  208  coupled moveable shaft  114  and a second end  210 ,  212  that receive and engage with a lift pin (e.g., one or lift pins  108 ,  110 ). Second end  210 ,  212  can include, for example, a recess  214 ,  216  to receive a bottom portion  218 ,  220  of one or lift pins  108 ,  110 . Lift pin support member  112  can be a unitary member, as illustrated. Alternatively, lift pin support member can include a plurality of arms coupled to a coupling that is coupled to moveable shaft  114 . 
       FIG.  1    illustrates lift pins  108 ,  110  when engaged with lift pin support member  112 , such that lift pin support member  112  engages with lift pins  108 ,  110  and causes top surface  128 ,  130  of lift pins  108 ,  110  to reside above surface  122 .  FIG.  2    illustrates lift pin support member  112 , when lift pin support member  112  is disengaged from lift pins  108 ,  110 —i.e., when moveable shaft  114  is moved in a downward position relative to the position of moveable shaft  114  in  FIG.  1   . As illustrated in  FIG.  2   , when lift pin support member  112  is disengaged from lift pins  108 ,  110 , lift pins  108 ,  110  are retained by susceptor  118 , allowing susceptor  118  to rotate, without requiring support member  112  and/or moveable shaft  114  to rotate. 
     Moveable shaft  114  is in the form of a hollow tube. Moveable shaft  114  can be formed of, for example, quartz. In accordance with exemplary embodiments of the disclosure, moveable shaft is configured to move a vertical distance of 5 to about 25 mm (or ˜17 mm). As a result, lift pins  108 ,  110  can move about 5 to about 25 mm (or ˜17 mm), and lift pins  108 , can extend to a height of up to about 5, 10, or 20 mm above surface  122 . 
     Susceptor  118  can be formed of, for example, SiC or SiC-coated graphite. In accordance with various examples of the disclosure, width W of susceptor  118  is relatively small to allow lift pin-assisted substrate transfer and processing in a single region—e.g., reaction region  104 . In accordance with various embodiments of the disclosure, a width W of susceptor  118  at a peripheral region  222  is less than a width of susceptor  118  at a center region  224  of susceptor  118 . This configuration can allow from a relatively thin susceptor—especially at the peripheral region—while allowing susceptor to rotate and perform other functions, such as protecting an end of a thermocouple and providing desired heat transfer to and/or from substrate  116 . By way of examples, the width at peripheral region  222  ranges from about 3 to about 6.5 mm (or ˜3.8 mm). A width of center region  224  can range from about 6 to about 10 mm (or ˜6.4 mm). 
     As noted above, reactor  100  can be configured to cause substrate  116  to rotate during substrate processing. In this illustrated example, reactor  100  includes a rotatable shaft  132  and a susceptor support  134  to cause susceptor  118 , and consequently substrate  116 , to rotate during processing. 
     Rotatable shaft  132  can be formed of, for example, quartz. Rotatable shaft  132  can be configured to couple to susceptor support  134  to translate rotational movement of rotatable shaft  132  to susceptor support  134 . By way of example, rotatable shaft  132  can be coupled to susceptor support  134  using a coupling  148 . 
     As illustrated in  FIGS.  1  and  2   , susceptor support  134  includes one or more (e.g., a plurality of) susceptor support arms  226 ,  228  and structures  136 ,  138 . Structures  136 ,  138  can engage with susceptor  118  and susceptor support arms  226 ,  228 . Alternatively, structures  136 ,  138  can be integrally formed with susceptor support arms  226 ,  228 . Susceptor support arms  226 ,  228  and structures  136 ,  138  can be formed of, for example, SiC, SiC-coated graphite, or quartz. Although illustrated with one structure  136 ,  138  for each susceptor support arms  226 ,  228 , susceptor support  134  can include a plurality of structures  136 ,  138  for each susceptor support arm  226 ,  228 . In accordance with exemplary embodiments of the disclosure, at least one of the plurality of susceptor support arms  226 ,  228  includes an aperture  140 ,  142  to receive a lift pin. 
     Reactor  100  can also include a thermocouple  144 . Thermocouple  144  can be used to measure a temperature of susceptor  118 —for example—during substrate processing. As illustrated in  FIG.  1   , thermocouple  144  can include an end  146 , which extends through moveable shaft and rotatable shaft. End  146  can reside within center region  224  of susceptor  118 . Center region  224  may provide additional radiation shielding for end  146  of thermocouple  144 . 
     In accordance with further exemplary embodiments of the disclosure, a substrate support assembly  230  includes components to cause lift pins  108 ,  110  to raise and lower and to cause susceptor  118  to rotate. In accordance with these embodiments, substrate support assembly  230  includes susceptor  118 , susceptor support  134 , rotatable shaft  132 , lift pin support member  112 , one or more lift pins  108 ,  110 , moveable shaft  114 , a lift pin mechanism to cause the moveable shaft to move in a vertical direction during a substrate transfer process, and a susceptor rotation mechanism that causes susceptor  118  to rotate during substrate processing. As noted above, in accordance with various examples of the disclosure, susceptor  118  does not move in a vertical direction during substrate transfer—i.e., susceptor  118  does not move in a vertical direction as lift pins are raised and/or lowered and/or during other steps of a substrate transfer process. As described below, the lift pin mechanism and the susceptor rotation mechanism can be combined. 
       FIGS.  3 - 5    illustrate a lift/rotate mechanism  300  in accordance with exemplary embodiments of the disclosure. Lift/rotate mechanism  300  can be used to raise and lower lift pins (e.g., lift pins  108 ,  110 ) and to cause a susceptor (e.g., susceptor  118 ) to rotate.  FIG.  3    illustrates a rear isometric view of lift/rotate mechanism  300 ,  FIG.  4    illustrates a front isometric view of lift/rotate mechanism  300 , and  FIG.  5    illustrates a simplified cross-sectional-view of lift/rotate mechanism  300 . 
     With reference to  FIGS.  3  and  4   , in the illustrated example, lift/rotate mechanism  300  includes a susceptor rotary actuator  302 , a pin lift actuator  304 , a rotary signal junction bracket, a tubulation seal  308 , a tubulation seal support  310 , a susceptor manual actuator  312 , a thermocouple signal rotary junction  314 , and a mounting bracket  316 . 
     Susceptor rotary actuator  302  is used to provide rotational movement to a susceptor, such as susceptor  118 . By way of example, susceptor rotary actuator  302  is configured to provide rotational movement to rotatable shaft  132  to cause susceptor  118  to rotate—e.g., during processing of a substrate—using rotational drive gear  512 . Exemplary rotational speed can range from about 5 rpm to about 150 rpm, about 10 rpm to about 50 rpm, or be about 35 rpm. 
     Pin lift actuator  304  is configured to cause lift pins (e.g., lift pins  108 ,  110 ) to move in a vertical direction. By way of example, pin lift actuator  304  causes a pin lift carriage  502  to move vertically along a linear slide rail  504 . Carriage  502  is mechanically coupled to moveable shaft  114  (e.g., using a pin lift shaft mounting sleeve  506 ) to cause lift pins (e.g., by way of lift pin support member  112 ) to move in a vertical direction. Pin lift shaft mounting sleeve  506  and moveable shaft  114  can be protected from the environment using an upper bellows  508  and a lower bellows  510 . 
     Rotary signal junction box  306  can be used to facilitate provision of signals to and/or from susceptor rotary actuator  302 , pin lift linear actuator  304 , and/or one or more thermocouples, such as thermocouple  144 . 
     Tubulation seal  308  and a tubulation seal support  310  are used to provide a seal about moveable shaft  114 . As illustrated in  FIG.  5   , tubulation seal  308  can include a seal  514  and a support plate  516  to retain seal  514  as moveable shaft  114  moves relative to seal  308 . 
     Although, in accordance with various embodiments of the disclosure, a susceptor does not move vertically during substrate processing, it may be desirable to move a susceptor for maintenance, installation, or the like. In such cases, susceptor manual actuator  312  can be used to manually move a susceptor (e.g., susceptor  118 ) in a vertical direction via a susceptor lift carriage  518 . 
     In the illustrated example, lift/rotate mechanism  300  includes a relatively large feedthrough  520  (e.g., having a diameter of about 20 to about 50 mm or be about 34.5 mm), which allows installation of moveable shaft  114 , through a rotary feedthrough  522  and a susceptor shaft mounting sleeve  524 , from below. A configuration of lift/rotate mechanism  300  is relatively compact, compared to lift/rotate mechanism that cause a susceptor to move vertically during a substrate transfer process. 
     In accordance with additional embodiments of the disclosure, a method of transferring and processing a substrate is provided. The method can employ the reactor, substrate support assembly, and/or lift/rotate mechanism as described herein. An exemplary method includes the steps of providing a reactor comprising a common region for substrate processing and substrate transfer, providing a substrate support assembly, providing a substrate to the common region, moving the lift pins in a downward position to place the substrate in a processing position, processing the substrate, moving the lift pins in an upward position, and removing the substrate from the common region. The step of removing the substrate can include removing the substrate from the common region through an opening in a reaction or processing region that is above a top surface of the susceptor. 
     Although exemplary embodiments of the present disclosure are set forth herein, it should be appreciated that the disclosure is not so limited. For example, although the apparatus and methods are described in connection with various specific components, the disclosure is not necessarily limited to these configurations. Various modifications, variations, and enhancements of the apparatus and methods set forth herein can be made without departing from the spirit and scope of the present disclosure.