Patent Publication Number: US-2021195695-A1

Title: Bake devices for handling and uniform baking of substrates

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of U.S. Provisional Patent Application Ser. No. 62/951,909, filed Dec. 20, 2019, which is herein incorporated by reference. 
    
    
     BACKGROUND 
     Field 
     Embodiments of the present disclosure generally relate to bake apparatuses for handling and uniform baking of substrates and methods for the handling and uniform baking of substrates. 
     Description of the Related Art 
     In the manufacture of optical devices, substrates may be heated to a temperature greater than 50 degrees Celsius (° C.), such as about 50° C. to about 300° C. Substrates, such as glass substrates, may include one or more materials that cause the substrates to bow at temperatures greater than 50° C. The one or more materials may be materials having a refractive index greater than 1.5. A substrate having a refractive index greater than 1.5 when heated to a temperature greater than 50° C. may have bowing of about 1 millimeter (mm) to about 2 mm from the edge of the substrate to the center of the substrate. Therefore, when disposed on a heated substrate support (such as a vacuum chuck, electrostatic chuck, or other substrate support operable to retain the substrate and heat the substrate via heating elements disposed therein) the edge of the substrate may not be retained on the heated substrate support resulting in non-uniform temperature across the surface of the substrate. 
     During, for example, post-apply baking (PAB) the non-uniform temperature across the surface of the substrate may cause non-uniform removal of solvents from a resist material disposed on the surface of the substrate resulting in a non-uniform resist layer. During, for example, post-exposure baking (PEB) the non-uniform temperature across the surface of the substrate may result in a non-uniform development (e.g., patterning) of the resist layer. Accordingly, what is needed in the art are bake apparatuses for handling and uniform baking of substrates and methods for the handling and the uniform baking of substrates. 
     SUMMARY 
     In one embodiment, an apparatus is provided. The apparatus includes a substrate holding assembly disposed on a base. The substrate holding assembly includes two or more shafts. Each shaft of the two or more shafts has extensions disposed thereon. The extensions of each shaft of the two or more shafts are operable to support one or more substrates disposed between the one or more shafts. The apparatus further includes a lid. The lid includes one or more heating elements disposed therein. The apparatus further includes a process volume formed between the lid and the base. 
     In another embodiment, an apparatus is provided. The apparatus includes a substrate support disposed on a base. The substrate support includes one or more heating elements and lift pins operable to support a substrate. The apparatus further includes a lid. The lid includes an edge brace coupled thereon. The edge brace includes a ring. The apparatus further includes a process volume formed between the lid and the base. 
     In yet another embodiment, a method is provided. The method includes disposing one or more substrates on a substrate holding assembly of a bake apparatus. The method further includes lowering a lid of the bake apparatus to form a process volume in the bake apparatus. The method further includes heating the process volume with one or more heating elements of the bake apparatus. The heating elements heat the one or more substrates uniformly or substantially uniformly. 
    
    
     
       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 its scope, and may admit to other equally effective embodiments. 
         FIGS. 1A and 1B  are schematic cross-sectional views of a bake apparatus according to an embodiment. 
         FIGS. 2A and 2B  are schematic cross-sectional views of a bake apparatus according to an embodiment. 
         FIG. 3  is a flow diagram of a method for baking one or more substrates in a bake apparatus according to an embodiment. 
         FIGS. 4A and 4B  are schematic cross-sectional views of a bake apparatus according to an embodiment. 
         FIG. 4C  is a schematic bottom view of an edge brace according to an embodiment. 
         FIG. 5  is a flow diagram of a method for baking a substrate in a bake apparatus according to an embodiment. 
         FIG. 6A  is a schematic exploded view of a device according to an embodiment. 
         FIG. 6B  is a schematic top view of a device according to an embodiment. 
         FIG. 6C  is a schematic cross-sectional views of a device according to an embodiment. 
         FIG. 7  is a flow diagram of a baking for heating a substrate in a bake apparatus according to an 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 
     Embodiments of the present disclosure generally relate to bake apparatuses for handling and uniform baking of substrates and methods for the handling and the uniform baking of substrates. The bake apparatuses allow the substrates to be heated to a temperature greater than 50° C. without bowing of about 1 mm to about 2 mm from the edge of the substrates to the center of the substrates. The bake apparatuses heat the substrates uniformly or substantially uniformly to improve substrate quality. 
       FIGS. 1A and 1B  are schematic cross-sectional views of a bake apparatus  100 . The bake apparatus  100  includes a base  102 , a lid  104 , and a substrate holding assembly  112 . The substrate holding assembly  112  includes two or more shafts  114  having one or more extensions  116  coupled thereto. The shafts  114  each have a shaft height  115 . In one embodiment, which can be combined with other embodiments described herein, the shaft height is between about 0.5 inch and about 5 inch. 
     The one or more extensions  116  of each of the shafts  114  are coupled opposite to each other such that one or more substrates  101  are supported by the extensions  116 . The extension  116  is in contact with portions of the edge of each of the substrates  101 . Although only three pairs of extensions  116  are shown in  FIGS. 1A and 1B , more or less than three pairs of extensions  116  can be included in the bake apparatus  100 . The number of pairs of extensions  116  corresponds to the number of substrates  101  in the bake apparatus  100 . Each extension  116  has an extension width  117 . The extension widths  117  correspond to the portion of the substrates  101  in contact with the extensions  116 . In one embodiment, which can be combined with other embodiments described herein, the extension width  117  is between about 1 mm and about 10 mm. A width  119  is defined between ends of the extensions  116  disposed opposite one another. The width  119  corresponds to the portion of the substrates  101  not in contact with the extensions  116 . The width  119  is between about 198 mm and about 298 mm. Although only three substrates  101  are shown in  FIG. 1B , the bake apparatus  100  is configurable to hold more than three of the substrates  101 . For example, the bake apparatus  100  is configurable to hold 1 to 5 of the substrates  101 . 
     In one embodiment, which can be combined with other embodiments described herein, the one or more substrates  101  include one or more materials that are subject to bowing at a temperature greater than 50° C., such as such as about 50° C. to about 300° C. In another embodiment, which can be combined with other embodiments described herein, the one or more substrates  101  include, but are not limited to, at least one of amorphous dielectrics, non-amorphous dielectrics, crystalline dielectrics, silicon oxide, polymers, and combinations thereof. For example, the one or more substrates  101  include at least one of glass, plastic, and polycarbonate materials that are subject to bowing at a temperature greater than 50° C. In yet another embodiment, which can be combined with other embodiments described herein, the one or more substrates  101  include, but are not limited to, at least one of an oxide, sulfide, phosphide, telluride, and combinations thereof. In one example, the substrates  101  include at least one of silicon (Si), silicon dioxide (SiO 2 ), sapphire, and high-index transparent materials containing materials. In yet another embodiment, which can be combined with other embodiments described herein, the substrates  101  have a refractive index greater than 1.5. In yet another embodiment, which can be combined with other embodiments described herein, the substrates  101  include a glass material having a refractive index greater than 1.5. 
     In one embodiment, which can be combined with other embodiments described herein, the substrates  101  have a thickness less than about 1 mm. In one embodiment, which can be combined with other embodiments described herein, the substrates  101  have a diameter of about 200 mm. In another embodiment, which can be combined with other embodiments described herein, the substrates  101  have a diameter of about 300 mm. In another embodiment, which can be combined with other embodiments described herein, the substrates  101  have a diameter of about 4 inch to about 12 inch. 
     The lid  104  includes an actuator  108  operable to raise and lower the lid  104  from a raised position (shown in  FIG. 1A ) to a lowered position (shown in  FIG. 1B ). The lid  104  in the raised position allows the one or more substrates  101  to be transferred to and from the bake apparatus  100 . In one embodiment, which can be combined with other embodiments described herein, the one or more substrates  101  are transferred to and from the bake apparatus  100  with a transfer robot. The lid  104  in the lowered position contacts the base  102  such that a process volume  103  is formed between the lid  104  and the base  102 . The process volume  103  provides a uniform or substantially uniform temperature distribution inside the process volume of the bake apparatus  100 . The process volume  103  may be heated by various heat sources. In one embodiment, which can be combined with other embodiments described herein, one or more heating elements  106  are disposed in the lid  104 . The one or more heating elements  106  include, but are not limited, to a ceramic heater, a rubber heater, and a fiber glass heater. The heating elements  106  are operable heat the process volume  103  between about 50° C. to about 600° C. The heating elements  106  heat the process volume  103  such that each substrate  101  of the one or more substrates  101  is uniformly or substantially uniformly heated. Additionally, the uniform or substantially uniform temperature distribution inside the process volume  103  exposes each portion of the one or more substrates  101  to the same temperature. For example, the portions of the one or more substrates  101  positioned on the extensions  116  are heated to the same temperature as the portions of the one or more substrates  101  corresponding to the width  119 . 
     Exposing each portion of the substrates  101  to the same temperature allows the one or more substrates  101  to be heated to the temperature greater than 50° C. without bowing. The bowing of the one or more substrates  101  is generally about 1 mm to about 2 mm from the edge of the substrates  101  to the center of the substrates  101 . During post-apply baking (PAB), for example, the uniform or substantially uniform or substantially uniform temperature across the surface of the one or more substrates  101  provides for a uniform or substantially uniform resist layer over the one or more substrates  101 . During post-exposure baking (PEB), for example, the uniform or substantially uniform temperature across the surface of the one or more substrates  101  provides for a uniform or substantially uniform development (e.g., patterning) of the resist layer over the one or more substrates  101 . 
     In one embodiment, which can be combined with other embodiments described herein, the temperature the one or more substrates  101  are exposed to in the process volume  103  is increased from about 40° C. to about 800° C. The rapid temperature increase bakes the one or more substrates  101 . In another embodiment, which can be combined with other embodiments described herein, the temperature the one or more substrates  101  are exposed to in the process volume  103  is decreased from about 800° C. to about 40° C. The rapid cooling of the one or more substrates is in preparation of transfer of the one or more substrates out of the process volume  103 . In another embodiment, which can be combined with other embodiments described herein, the temperature the one or more substrates  101  are exposed to in the process volume  103  is maintained during a PEB process at about 80° C. to about 150° C. In yet another embodiment, which can be combined with other embodiments described herein, the temperature the substrates  101  are exposed to in the process volume  103  is maintained during a PAB process at about 80° C. to about 300° C. The embodiments of the bake apparatus  100  of  FIGS. 1A and 1B  include a controller  110  to control operation of the bake apparatus  100  and methods described herein. For example, the controller  110  is operable to adjust the temperature of the process volume  103  to match the desired temperature of the process volume  103 . 
       FIGS. 2A and 2B  are schematic cross-sectional views of a bake apparatus  200 . The bake apparatus  200  includes a base  202 , a lid  204 , and the substrate holding assembly  112  described herein. The lid  204  includes actuated door  208  operable to move from an open position (shown in  FIG. 2A ) to a closed position (shown in  FIG. 2B ). The lid  204  in the open position allows substrates  101  to be transferred to and from the bake apparatus  200 . In one embodiment, which can be combined with other embodiments described herein, the one or more substrates  101  are transferred to and from the bake apparatus  200  with a transfer robot. The actuated door  208  in the closed position contacts the lid  204  such that a process volume  103  is formed between the lid  204  and the base  202 . The process volume  103  provides the uniform or substantially uniform temperature distribution inside the process volume  103  of the bake apparatus  200 . The process volume  103  may be heated by various heat sources. In one embodiment, which can be combined with other embodiments described herein, the one or more heating elements  106  are disposed in the lid  204 . The one or more heating elements  106  are operable to heat the process volume  103  between about 50° C. to about 600° C. The heating elements  106  heat the process volume  103  such that each substrate  101  of the one or more substrates  101  is equally heated. 
     In one embodiment, which can be combined with other embodiments described herein, the temperature the one or more substrates  101  are exposed to in the process volume  103  is increased from about 40° C. to about 800° C. In another embodiment, which can be combined with other embodiments described herein, the temperature the one or more substrates  101  are exposed to in the process volume  103  is decreased from about 800° C. to about 40° C. In another embodiment, which can be combined with other embodiments described herein, the temperature the one or more substrates  101  are exposed to in the process volume  103  is maintained during a PEB process at about 80° C. to about 150° C. In yet another embodiment, which can be combined with other embodiments described herein, the temperature the substrates  101  are exposed to in the process volume  103  is maintained during a PAB process at about 80° C. to about 300° C. The embodiments of the bake apparatus  200  of  FIGS. 2A and 2B  include a controller  210  to control operation of the bake apparatus  200  and methods described herein. 
       FIG. 3  is a flow diagram of a method  300  for baking one or more substrates  101  in the bake apparatus  100  or the bake apparatus  200 . At operation  301 , the one or more substrates  101  are transferred into the bake apparatus  100  or the bake apparatus  200 . Each substrate  101  of the one or more substrates  101  is placed on the extensions  116 . At operation  302 , the bake apparatus  100  or the bake apparatus  200  moves form the open position to the closed position. In one embodiment which can be combined with other embodiments described herein, the lid  104  is lowered by the actuator  108  to the closed position. The lid  104  contacts the base  102  and forms the process volume  103 . In another embodiment, which can be combined with other embodiments described herein, the actuated door  208  is lowered to the closed position. The actuated door  208  contacts the lid  204  and forms the process volume  103 . 
     At operation  303 , the process volume  103  is heated. The process volume  103  is heated by the one or more heating elements  106 . The one or more heating elements  106  are disposed in the lid  104  or the lid  204 . Each substrate  101  of the one or more substrates  101  is heated equally in the process volume  103  to the desired temperature. The equal heating of the one or more substrates  101  prevents bowing of the one or more substrates  101 . At operation  304 , the bake apparatus  100  or the bake apparatus  200  moves form the closed position to the open position. In one embodiment, which can be combined with other embodiments described herein, the lid  104  is raised by the actuator  108  to the open positon (shown in  FIG. 1A ). In another embodiment, which can be combined with other embodiments described herein, the actuated door  208  is raised to the open position (shown in  FIG. 2A ). The one or more substrates  101  can be transferred out of the process volume  103 . The controller  110  and the controller  210  are in communication with the bake apparatus  100  and the bake apparatus  200 . The controller  110  and the controller  210  control the operation of the method  300  and facilitate the baking process. 
       FIGS. 4A and 4B  are schematic cross-sectional views of a bake apparatus  400 .  FIG. 4C  is a schematic bottom view of an edge brace  424  of the bake apparatus  400 . The bake apparatus  400  includes a base  402 , a lid  404 , and a substrate support  416 . Substrate support  416  is one of a vacuum chuck, electrostatic chuck, any other substrate support operable to retain substrates  101  described herein. The substrate support  416  is operable to heat a substrate  101  via heating elements  106  disposed therein. The one or more heating elements  106  include, but are not limited to, a ceramic heater, a rubber heater, and a fiber glass heater. 
     In one embodiment, which can be combined with other embodiments described herein, the temperature the substrate  101  is exposed to by the substrate support  416  is increased from about 40° C. to about 800° C. In another embodiment, which can be combined with other embodiments described herein, the temperature the substrate  101  is exposed to by the substrate support  416  is decreased from about 800° C. to about 40° C. In another embodiment, which can be combined with other embodiments described herein, the temperature the substrate  101  is exposed to by the substrate support  416  is maintained during the PEB process at about 80° C. to about 150° C. In yet another embodiment, which can be combined with other embodiments described herein, the temperature the substrate  101  is exposed to by the substrate support  416  is maintained during the PAB process at about 80° C. to about 300° C. 
     The lid  404  includes actuator  408  operable to raise and lower the lid  404  from a raised position (shown in  FIG. 4A ) to a lowered position (shown in  FIG. 4B ). The lid  404  in the raised position allows a substrate  101  to be transferred to and from the bake apparatus  100  and positioned on the substrate support  416 . In one embodiment, which can be combined with other embodiments described herein, the substrate  101  is transferred to and from the bake apparatus  400  with a transfer robot. In one embodiment, which can be combined with other embodiments described herein, the substrate support  416  includes one or more lift pins  422 . The lift pins  422  support the substrate  101 . The lid  404  in the closed position contacts the base  402  such that a process volume  103  is formed between the lid  404  and the base  402 . 
     In the closed position, a ring  426  of the edge brace  424  contacts edge portions of the substrate  101 . The edge brace  424  is coupled to the lid  404 . The ring  426  of the edge brace  424  contacting the edge portions of the substrate  101  forces the edge portions of the substrate  101  against the surface of the substrate support  416 . The substrate  101  is subjected to a uniform or substantially uniform temperature distribution when the substrate  101  is heated by the substrate support  416 . In one embodiment, which can be combined with other embodiment described herein, the lift pins  422  are recessed into the substrate support  416  when in the closed position. The lift pins  422  are recessed such that the substrate  101  is in direct contact with the substrate support  416 . 
     The ring  426  of the edge brace  424  has a ring width  427 . The ring width  427  corresponds to the diameter of the substrate  101 . For example, the ring width  427  is between about 200 mm and about 300 mm. The ring  426  may have different surface profiles  428  that contact the edge portions of the substrate  101  to force the edge portions of the substrate  101  against the surface of the substrate support  416  uniformly or substantially uniformly. The surface profiles  428  include but are not limited to a rectangular, triangular, or trapezoidal shape. The embodiments of the bake apparatus  400  of  FIGS. 4A-4C  include a controller  410  to control operation of the bake apparatus  400  and methods described herein. 
     Heating each portion across the surface of the substrate  101  to the same temperature allows the substrate  101  to be heated to a temperature greater than 50° C. The heating elements  106  heat the process volume  103  between about 50° C. to about 600° C. During PAB, for example, the uniform or substantially uniform temperature across the surface of the substrate  101  provides for the uniform or substantially uniform resist layer over the substrate  101 . During PEB, for example, the uniform or substantially uniform temperature across the surface of the substrate  101  provides for the uniform or substantially uniform development (e.g., patterning) of the resist layer over the substrates. 
       FIG. 5  is a flow diagram of a method  500  for baking one or more substrates  101  in the bake apparatus  400 . At operation  501 , the substrate  101  is transferred into the bake apparatus  400 . The substrate  101  is placed on the substrate support  416 . At operation  502 , the bake apparatus  400  moves from the open position to the closed position. The lid  404  and the ring  426  are lowered. The lid  404  is lowered by the actuator  408  such that the lid  404  contacts the base  402  and forms the process volume  103 . The ring  426  is lowered such that the ring  426  contacts the substrate  101 . At operation  503 , the process volume  103  is heated. The process volume  103  is heated by the one or more heating elements  106  in the substrate support  416 . The substrate  101  is uniformly or substantially uniformly heated in the process volume  103 . The entire surface of the substrate  101  is in contact with the substrate support  416  due to the force applied by the ring  426 . At operation  504 , the lid  404  is raised. The lid  404  is raised by the actuator  408  such that the bake apparatus  400  is in the open position (shown in  FIG. 4A ). The substrate  101  can be transferred out of the process volume  103 . The controller  410  controls the operation of the method  500 . The controller  410  is in communication with the lid  404  and the base  402  such that the controller can control the bake apparatus  400  and facilitate the baking process. 
       FIG. 6A  is a schematic exploded view of a device  600 .  FIG. 6B  is a schematic top view of the device  600 .  FIG. 6C  is a schematic cross-sectional view of the device  600 . The device  600  includes a retention plate  604  and a heating plate  602 . The retention plate  604  includes, but is not limited to, a conductive material such as ceramic, mica, or a mixture of ceramic and metal materials. The retention plate  604  has a retention plate width  605 . The retention plate width  605  is between about 202 mm and about 350 mm. In one embodiment, which can be combined with other embodiments described herein, a transfer robot positions the substrate  101  on the retention plate  604 . In the embodiment, the retention plate  604  moves on a track and is positioned on the heating plate  602 . In another embodiment, which can be combined with other embodiments described herein, the heating plate  602  moves on a track and is positioned under the retention plate  604 . In the embodiment, which can be combined with other embodiments described herein, the substrate  101  is positioned on the retention plate  604  having the heating plate  602  thereunder. In yet another embodiment, which can be combined with other embodiments described herein, the retention plate  604  and heating plate  602  move on tracks to be properly positioned relative to the other. 
     The retention plate  604  is one of a vacuum chuck, electrostatic chuck, or any other substrate support operable to retain substrates  101  described herein. In one embodiment, as shown in  FIGS. 6A and 6C , the retention plate  604  includes a vacuum system  606  having one or more channels  608  connected to a pump  612 . The pump is operable to provide suction through the channels  608  to retain a substrate  101 . The retention plate  604  has a thickness  614  that allows heat provided by the heating plate  602  to dissipate uniformly or substantially uniformly across the retention plate  604 . The thickness  614  is between about 1 cm and about 10 cm. The heating plate  602  is operable to heat a substrate  101  via heating elements  106  disposed therein. The substrate  101  is subjected to a uniform or substantially uniform temperature distribution when the substrate  101  is heated by the retention plate  604 . The vacuum system  606  retains the substrate  101  such that the heating plate  602  is in contact with the entire surface of the substrate  101 . Therefore, the entire surface of the substrate  101  is uniformly or substantially uniformly heated. 
     As discussed, heating each portion across the surface of the substrate  101  to the same temperature allows the substrate  101  to be heated to the temperature greater than 50° C. without bowing of about 1 mm to about 2 mm from the edge of the substrate  101  to the center of the substrate  101 . In one embodiment, which can be combined with other embodiments described herein, the device  600  can be utilized in the bake apparatus  400 . For example, the retention plate  604  and the heating plate  602  may replace the substrate support  416  of the bake apparatus  400 . 
     In one embodiment, which can be combined with other embodiments described herein, the temperature the one or more substrates  101  are exposed to in the process volume  103  is increased from about 40° C. to about 800° C. In another embodiment, which can be combined with other embodiments described herein, the temperature the one or more substrates  101  are exposed to in the process volume  103  is decreased from about 800° C. to about 40° C. In another embodiment, which can be combined with other embodiments described herein, the temperature the one or more substrates  101  are exposed to in the process volume  103  is maintained during a PEB process at about 80° C. to about 150° C. In yet another embodiment, which can be combined with other embodiments described herein, the temperature the substrates  101  are exposed to in the process volume  103  is maintained during a PAB process at about 80° C. to about 300° C. The embodiments of the device  600  of  FIGS. 6A-6C  include a controller  610  to control operation of the device  600  and methods described herein. 
       FIG. 7  is a flow diagram of a method  700  for heating the substrate  101  in the device  600 . At operation  701 , the substrate  101  is positioned over the heating plate  602  and the retention plate  604 . The heating plate  602  and the retention plate  604  can be positioned relative to each other by moving on tracks. The retention plate  604  is disposed over the heating plate  602 . The substrate  101  is positioned by a transfer robot. At operation  702 , the substrate  101  is retained on the retention plate  604  by the vacuum system  606 . The vacuum system  606  utilizes the pump  612  to provide suction through the channels  608  to retain the substrate  101  on the retention plate  604 . At operation  703 , the heating plate  602  provides heat to the substrate  101 . The heat from the heating plate  602  passes through the retention plate  604  to heat the substrate  101 . At operation  704 , the substrate  101  is removed from the device  600 . In one embodiment, which can be combined with other embodiments described herein, prior to the operation  703  a ring such as the ring  426  from the bake apparatus  400  is lowered into contact with the substrate  101 . The ring  426  and the vacuum system  606  retain the substrate  101  on the retention plate  604  such that the substrate  101  does not bow. Therefore, the substrate  101  is uniformly or substantially uniformly heated. 
     In summation, bake apparatuses for handling and uniform or substantially uniform baking of substrates and methods for the handling and the uniform or substantially uniform baking of substrates are described herein. The bake apparatuses allow the substrates to be heated to a temperature greater than 50° C. without bowing of about 1 mm to about 2 mm from the edge of the substrates to the center of the substrates. The bake apparatuses heat the substrates uniformly or substantially uniformly to improve substrate quality. 
     While the foregoing is directed to examples of the present disclosure, other and further examples of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.