Patent Publication Number: US-2021173295-A1

Title: Reticle processing system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present disclosure claims priority to U.S. provisional application Ser. No. 62/944,097, filed on Dec. 5, 2019, the entire content of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     Embodiments of the present disclosure relate generally to lithography mask blank processing and, more specifically, to a reticle processing system and associated methods for processing lithography mask blanks using the reticle handling system. 
     BACKGROUND 
     Extreme ultraviolet lithography (EUV), also known as soft x-ray projection lithography, has begun to replace deep ultraviolet lithography for the manufacture of 0.13 micron, and smaller, minimum feature size semiconductor devices. EUV systems operate by reflection instead of transmission of light. Through the use of a series of mirrors, or lens elements, and a reflective element, or a mask blank, coated with a non-reflective absorber mask pattern, patterned actinic light is reflected onto a resist-coated semiconductor wafer. 
     Conventional EUV mask blank processes may include, for example, a 152 mm×152 mm blank reticle being placed into various processing chambers to apply various material layers. As configured, the square reticle is sandwiched within a carrier assembly (e.g., a 300 mm carrier assembly) to enable the reticle to be transferred through an EUV mask blank production system like a 300 mm wafer. The carrier assembly may include a carrier base, the reticle blank, and a carrier top shield. 
     During processing, every time the reticle blank is transported into the EUV mask blank production system, the elements of the carrier assembly are brought together and separated apart. This process involves multiple lifts and clamps for separating the carrier base and the carrier top shield so a reticle can be placed therebetween. The lifts can be extended or retracted to open or close the carrier assembly. The carrier top shield is used on top of carrier base assembly to prevent deposition of material on the carrier base. Controlling the defects during handling of the mask blank is quite challenging. In addition, a carrier bases is typically comprised of a machined aluminum piece, and it is difficult to provide a carrier base having zero flatness. When the carrier base sits on a pedestal of a deposition chamber having a flatness of 0.001″, the carrier base contacts pedestal high point and slips during rotation of the pedestal, generating particles. 
     A carrier base also has multiple pockets required for camera inspection to align the carrier base and the carrier top shield. Pockets are also required for detecting the carrier top shield, machining, mounting pads and resting pins, which are potential source for passage of particles generated during slippage of the carrier base on a pedestal in a processing chamber. A carrier top shield mounted at higher level than the reticle is yet another potential source of particle falling on the substrate after deposition of a material layer on the reticle, which can lead to edge roll effect causing non uniform deposition on the reticle. Improved handling systems for EUV mask blanks and reticles to address one or more of these problems are needed. 
     SUMMARY 
     A first embodiment pertains to a reticle processing system comprising a support assembly including a plate coupled to a frame; and a carrier base assembly configured to be positioned on the support assembly, the carrier base assembly comprising a carrier base comprising top surface and a wall extending from the carrier base defining a containment region, the containment region sized and shaped to contain an EUV reticle. 
     A second embodiment pertains to a carrier base assembly comprising a carrier base comprising top surface and a wall extending from carrier base defining a containment region, the containment region sized and shaped to contain an EUV reticle; and an EUV reticle contained within the containment region. 
     An exemplary method embodiment pertains to a method of processing an EUV reticle blank, the method comprising providing a carrier base assembly including a carrier base and a reticle blank, the carrier base comprising top surface and a wall extending from carrier base defining a containment region, the containment region sized and shaped to contain the EUV reticle; placing the carrier base atop a support assembly, the support assembly including a plate coupled to a frame; depositing the reticle blank within containment region of the carrier base; and removing the carrier base assembly from the support assembly. 
    
    
     
       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 embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. The drawings are not necessarily to scale. The drawings are merely representations, not intended to portray specific parameters of the disclosure. Furthermore, the drawings are intended to depict exemplary embodiments of the disclosure, and therefore, are not considered as limiting in scope. 
         FIG. 1  shows a schematic of an exemplary extreme ultraviolet mask production system in accordance with certain aspects of the present disclosure; 
         FIG. 2  is a perspective view of a prior art reticle processing system; 
         FIG. 3  is a side view of the reticle processing system of  FIG. 2 ; 
         FIG. 4  is an exploded perspective view of the reticle processing system of  FIG. 2 ; 
         FIG. 5  is a perspective view of a prior art support assembly of the reticle processing system of  FIG. 2 ; 
         FIG. 6  is a top view of a carrier base of the reticle processing system of  FIG. 2 ; 
         FIG. 7  is a side cross-sectional view of the reticle processing system of  FIG. 2 ; 
         FIG. 8  is a schematic view of a reticle on a prior art carrier base; 
         FIG. 9  is a bottom plan view of a carrier base according to an embodiment of the disclosure; 
         FIG. 10  is a top plan view of a carrier base assembly showing the carrier base of  FIG. 9  and a reticle atop the carrier base; 
         FIG. 11  is a side view of the carrier base assembly of  FIG. 10 ; 
         FIG. 12A  is a detailed view of an edge portion of a carrier base according to an embodiment of the disclosure; 
         FIG. 12B  is a detailed view of an edge portion of a prior art carrier base; 
         FIG. 13  is a detailed view of an end of a carrier base assembly showing an edge of the reticle adjacent the wall of the carrier base according to an embodiment of the disclosure; 
         FIG. 14  an exploded perspective view of the reticle processing system according to an embodiment of the disclosure; 
         FIG. 15  is a perspective view of a support assembly of the reticle processing system of  FIG. 14 ; 
         FIG. 16  is a side view of the reticle processing system of  FIG. 14 ; and 
         FIG. 17  is a flowchart illustrating an exemplary method for processing a reticle according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments in accordance with the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings. The workpiece aligner apparatus and methods described herein may be embodied in many different forms and are not to be construed as being limited to the embodiments set forth herein. Instead, these embodiments are provided so this disclosure will be thorough and complete, and will fully convey the scope of the system and method to those skilled in the art. 
     For the sake of convenience and clarity, terms such as “top,” “bottom,” “upper,” “lower,” “vertical,” “horizontal,” “lateral,” and “longitudinal” will be used herein to describe the relative placement and orientation of these components and their constituent parts with respect to the geometry and orientation of a component of a device as appearing in the figures. The terminology will include the words specifically mentioned, derivatives thereof, and words of similar meaning and/or significance. 
     As used herein, an element or operation recited in the singular and proceeded with the word “a” or “an” is to be understood as including plural elements or operations, until such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the present disclosure are not intended as limiting. Additional embodiments may also incorporate the recited features. 
     As stated above, provide herein are approaches for processing reticle blanks. In one approach, a reticle processing system includes a support assembly having a plate coupled to a frame, and a carrier assembly coupled to the support assembly. The reticle processing system described herein may reside in a “clean” laminar flow region of a mini-environment instead of, for example, a stand-alone pod having no laminar flow and occupying one of the load port positions. In one approach, the carrier assembly includes a carrier base coupled to the plate, a reticle disposed over the carrier base, and a carrier top shield disposed over the reticle, wherein the carrier top shield has a central opening formed therein, providing ingress/egress for the reticle. In one approach, when the carrier assembly is placed atop the support assembly, a plurality of pins extend from the plate through corresponding openings in the carrier base, the plurality of pins supporting the carrier assembly so the carrier base, the reticle, and the carrier top shield are each independently supported and vertically separated from one another. 
     With reference now to the figures,  FIG. 1  depicts an EUV mask blank production system  100 . The EUV mask production system  100  may include a mask blank loading and carrier handling system  102  receiving one or more mask blanks  104 . An airlock  106  provides access to a wafer handling vacuum chamber  108 . In the embodiment shown, the wafer handling vacuum chamber  108  contains two vacuum chambers, e.g., a first vacuum chamber  110  and a second vacuum chamber  112 . Within the first vacuum chamber  110  is a first wafer handling system  114 , and in the second vacuum chamber  112  is a second wafer handling system  116 . 
     In one or more embodiments, the wafer handling vacuum chamber  108  has a plurality of ports around its periphery for attachment of various other systems. In this non-limiting embodiment, the first vacuum chamber  110  has a degas system  118 , a first physical vapor deposition system  120 , a second physical vapor deposition system  122 , and a pre-clean system  124 . Furthermore, the second vacuum chamber  112  is shown as including a first multi-cathode source  126 , a flowable chemical vapor deposition (FCVD) system  128 , a cure system  130 , and a second multi-cathode source  132  connected to it. 
     The first wafer handling system  114  is configured to move wafers, such as a wafer  134 , among the airlock  106  and the various systems around the periphery of the first vacuum chamber  110  and through slit valves in a continuous vacuum. The second wafer handling system  116  is configured to move wafers, such as a wafer  136 , around the second vacuum chamber  112 , while maintaining the wafers in a continuous vacuum. The integrated EUV mask production system  100  may operate with a reticle processing system described below. 
     Referring to  FIGS. 2-4 , a prior art reticle processing system  200  in use with a prior art carrier base  218  is shown. As shown, the reticle processing system  200  (hereinafter “system”) includes a carrier assembly  202  coupled to and supported by a support assembly  204 . The support assembly  204  includes a plate  208  coupled to a frame  210  extending partially along a periphery of the plate  208 . As shown, the plate  208  is coupled to the frame  210  by a set of fasteners  212 A-C extending through openings of the frame  210 . Although not limited to any particular type, the fasteners  212 A-C may include nuts and bolts extending through the plate  208  and the frame  210 , wherein a spring  214  is provided around the bolt to provide flexibility/resiliency to the fasteners  212 A-C. As shown, the frame  210  has an L-shaped configuration and the plate  208  a hexagonal shape, thus permitting the support assembly  204  to be secured to a corner within a processing chamber. This configuration is non-limiting, as other geometries for the frame  210  and the plate  208  may be possible depending on the specific application and processing environment. 
     As shown, the carrier assembly  202  includes a prior art carrier base  218  and a carrier top shield  220  respectively disposed below and above a reticle blank  222 . The carrier top shield  220  includes a central opening  224  formed therein to permit access to and ingress/egress of the reticle blank  222  during processing. As shown, the central opening  224  of the carrier top shield  220  is generally aligned over the reticle blank  222 . In one non-limiting approach, the reticle blank  222  is an EUV mask blank having an ultra-low thermal expansion substrate of glass, silicon, or other ultra-low thermal expansion material. The ultra-low thermal expansion materials may include fused silica, fused quartz, calcium fluoride, silicon carbide, silicon oxide-titanium oxide alloy, or other material having a thermal coefficient of expansion within the range of these materials. 
     As shown in  FIGS. 4-7 , the plate  208  of the prior art system  200  includes a first set of pins  228 A-C, a second set of pins  230 A-C, and a third set of pins  232 A-C, each extending vertically, or generally vertically, from a top surface  234  of the plate  208 . The second set of pins  230 A-C is positioned closer to a center section  238  of the plate  208  than the first set of pins  228 A-C, and the first set of pins  228 A-C is positioned closer to the center section  238  of the plate  208  than the third set of pins  232 A-C. Each of the first, second, and third sets of pins  228 A-C,  230 A-C, and  232 A-C are arranged in a triangular pattern for supporting each component of the carrier assembly  202 , while minimizing the number of contact points between the plurality of pins and the carrier assembly. 
     Referring now to  FIGS. 5-7 , during operation, the support assembly  204  receives the carrier assembly thereupon. More specifically, the prior art carrier base  218  is lowered onto the plate  208  causing the first set of pins  228 A-C to extend through a corresponding first set of openings  242 A-C within the prior art carrier base  218 . As shown, the first set of pins  228 A-C generally extend vertically higher than the second and third set of pins  230 A-C and  232 A-C so as to come into contact with a bottom surface  244  of the carrier top shield  220  once assembled. The first set of pins  228 A-C support and elevate the carrier top shield  220  over the reticle  222 . The first set of pins  228 A-C each includes a domed upper tip  246  for minimally engaging the bottom surface  244  of the carrier top shield  220 . 
     Furthermore, as the prior art carrier base  218  is lowered on the plate  208 , the second set of pins  230 A-C extend through a corresponding second set of openings  250 A-C within the carrier base and engage the reticle  222 . The openings  250 A and  250 D are camera inspection openings. As shown, the second set of pins  230 A-C generally extend vertically higher than the third set of pins  232 A-C, yet not as high as the first set of pins  228 A-C. Each of the second set of pins  230 A-C includes an upper face  254  engaging a bottom surface  258  of the reticle  222  to support the reticle over the carrier base  218 . The upper face  254  slopes downward towards the center section  238  of the plate  208 . 
     Referring back to  FIG. 7 , the plurality of pins  228 A-C,  230 A-C, and  232 A-C support the carrier assembly  202  so the prior art carrier base  218  at a bottom surface  264  thereof, the reticle  222 , and the carrier top shield  220  are each independently supported and vertically separated from one another. During use, when the carrier assembly  202  is placed on the support assembly  204 , the components of the carrier assembly are not in direct contact with one another. Specifically, the plurality of pins support the components of the carrier assembly  202  in a way so the carrier base  218  is vertically separated from the plate  208  by a first gap  268 , the reticle  222  is vertically separated from the carrier base  218  by a second gap  270 , and the carrier top shield  220  is separated from the reticle  222  by a third gap  272 . The placement and relative heights of the plurality of pins  228 A-C,  230 A-C, and  232 A-C, as well as the corresponding openings through the carrier base  218 , enable the demonstrated separation between components of the carrier assembly  202  when positioned atop the support assembly  204 . 
     As further shown in  FIG. 7 , the prior art system  200  may include a sensor system  280  for aligning the carrier assembly  202  to the support assembly  204 . For example, one or more sensors  282 A-C is used to verify whether each of the carrier assembly components (e.g., the carrier top shield  220 , the reticle  222 , or the carrier base  218 ) is correctly “in-position” on the support assembly  204 . This also prevents a user from inadvertently placing the carrier assembly  202  or reticle  222  on the support assembly  204  if one is already in position. 
     As shown in  FIG. 7 , a first sensor  282 -A monitors a first scan area  51  for detecting a presence and placement of the carrier base  218 , a second sensor  282 -B monitors a second scan area S 2  for detecting a presence and placement of the reticle  222 , and a third sensor  282 -C monitors a third scan area S 3  for detecting a presence and placement of the carrier top shield  220 . The sensors may transmit an output/feedback to a processor (not shown) of the sensor system  280  for subsequent analysis/processing. 
     During operation, the sensor system  280  is used in conjunction with a robot (not shown), such as a factory interface (H) robot, to accurately place the carrier assembly  202 , including the reticle  222 , onto the carrier assembly  202 , where the carrier assembly  202  can be assembled or dis-assembled. Furthermore, the sensor system  280  is used to verify the carrier assembly  202 , including the reticle  222 , are assembled correctly prior to being delivered to the loadlock. Advantageously, the robot is the sole moving component, ensuring the system  200  is not subject to unnecessary lifts or multiple robots, thus minimizing positional errors. For example, the vertical pick up and drop off trajectory of the robot is virtually identical, unlike when multiple, different lifts are employed. 
     As discussed above, and with reference to  FIG. 8 , which is a schematic view of a prior art carrier base  218  on a rotating pedestal  209  rotating about axis  217 . It is very difficult to obtain flatness across the bottom surface  218   b  of the prior art carrier base  218 , which results and friction (represented by arrows  211 ) between the pedestal and the bottom surface  218   b  of the carrier base  218  causing generation of particles  215  from deposited material  225  deposited in the gaps shown by arrows  213 . The prior art carrier base  218  has multiple gaps and openings (e.g., openings  242 A-C and openings  250 A-D) which are source of migration of particles  215  from the pedestal  209  to top of the reticle  222  through these openings as shown by the arrows  213 . 
     Referring now to  FIG. 9 , a top plan view of a carrier base  318  according to one or more embodiments comprises a bottom surface  318   b  is shown as including a peripheral rim  319 , which provides relief or a gap between the region  318   r  bounded by the peripheral rim  319  and which avoids friction between the surface of pedestal and the carrier base  318 . The peripheral rim  319  defines a peripheral edge  321 , and the carrier base  318  has an overall diameter D 1 . The peripheral rim  319  has a width W, and the region  318   r  bounded by the peripheral rim has a diameter D 2 . Thus, the width W is the difference between D 1  and D 2  so that D 1 −D 2 =W. 
       FIG. 10  is a bottom plan view of a carrier base assembly  302  comprising the carrier base  318  of  FIG. 9  and a reticle  322  mounted on top surface  318   t  of the carrier base  318 . A wall  323  extending from the carrier base top surface  318   t  forms a containment region  329  to hold the reticle  322  on the top surface  318   t  of the carrier base  318 . As best shown in  FIG. 11 , contact between the bottom surface  318   b  of the carrier base  318  in the region  318   r  bounded by the peripheral rim  319  and the pedestal is avoided and a gap G (or relief) is provided between the bottom surface  318   b  of the carrier base  318  and the pedestal  309  in the region  318   r . The region  318   r  of the carrier base  318  may be referred to as the central region of the carrier base  318 . The only contact between the carrier base  318  and the pedestal  309  is at the rim  319  bottom surface  319   b  at the outer periphery of the carrier base  318 . In the event that there is relative motion causing friction between the bottom surfaces  319   b , any particles generated by are far away from the quality blank area. The peripheral rim can have a thickness T 1  in a range of from 0.005 inches to 0.100 inches (0.127 mm to 2.54 mm), from 0.010 inches to 0.090 inches (0.254 mm to 2.29 mm), from 0.010 inches to 0.080 inches (0.254 mm to 2.03 mm), or from 0.010 to 0.070 (0.254 mm to 1.78 mm) inches or from 0.010 inches to 0.060 inches (0.254 mm to 1.52 mm). According to one or more embodiments, the thickness T 1  is configured to provide a gap G that reduces particle accumulation on a reticle held by the carrier base  318  during a physical vapor deposition process when the carrier base  318  holding the reticle  322  is placed on a pedestal  309  of a physical vapor deposition process chamber. In one or more embodiments, the area  331  under the reticle  322 , which in some embodiments is referred to a quality reticle area, is free from particles  315  during a physical vapor deposition process which might be generated by deposited material  325  and friction between the carrier base  318  and the pedestal  309 . 
       FIG. 12A  shows details on the bottom surface  319   b  of the carrier base rim  319  compared with a prior art design shown in  FIG. 12B . As shown in  FIG. 12A , the rim has a width W, and a thickness T 1  defined by the distance from bottom surface  318   b  of the carrier base  318  central region and bottom surface  319   b  of the rim. The carrier base  318  has an overall thickness T 2  at flat outer edge  318   o  having a dimension E. A top edge tapered portion  318   e  tapers from top surface  318   t  of the carrier base  318 . An angle A is formed between tapered edge portion  318   e  and flat outer edge  3180 . The angle A is in a range of from 160 degrees to 180 degrees, for example 170 degrees or 175 degrees. Compared with the prior art carrier base  218 , comprising bottom surface  218   b , top edge  218   t  having a dimension E, flat outer edge  218   o  and tapered edge  218   e  defining an angle A. As can be seen from a comparison of  FIG. 12A  according to one or more embodiments of the disclosure with  FIG. 12B , there is not a peripheral rim in  FIG. 12B  defining a thickness T 1  defined by the distance from bottom surface  318   b . The carrier base  218  has an overall thickness T 2  at flat outer edge  2180 . The bottom surface  218   b  in  FIG. 12B  is flat, and when the bottom surface  218   b  is placed on a pedestal, there is no gap G defined by thickness T 1  as shown in  FIG. 11 . 
       FIG. 13  shows an enlarged partial side view of the carrier base wall  323  extending from the top surface  318   t  thereof. The carrier base wall has an overall height H and a top surface  323   t . As shown in  FIG. 13 , when the reticle  322  is placed in containment region  329 , edge  322   e  of the reticle  322  is spaced a distance S from an inner wall surface  323   a  of the wall  323  facing the reticle edge  322   e . In addition, when the reticle is placed on the top surface  318   t  of the carrier base  318 , and when the reticle  322  is resting on pins during a deposition process, the top surface  322   t  of the reticle  322  is lower than the top surface  323   t  of the wall  323 . The top surface  322   t  of the reticle  322  is below the top surface  323   t  of the wall  323  by a distance B. Only one resting pin  378  having a domed surface  379  is shown in the partial view of  FIG. 13 . However, a plurality of resting pins  378  having domed surfaces  379  can be utilized according to one or more embodiments. In one or more embodiments, there are two resting pins  378 , three resting pins  378 , four resting pins  378 , five resting pins  378  or more than five resting pins  378 . Experiments were conducted to optimize spacing S between the edge  322   e  of the reticle and the wall surface  323   a , height H of the wall and the distance B that the wall  323  top surface  323   t  extends beyond the top surface  322   t  of the reticle  322  to reduce deposition of material on the wall surface  323   a  of the carrier base wall  323 , to achieve more uniform deposition on the reticle, and reduce particle generation on the reticle. In some embodiments, the spacing S is in a range of from 0.5 mm to 1 mm, and the distance B is in a range of from −1 mm to about 1 mm. It will be understood that when the distance B is a negative value, the top surface  323   t  is below the top surface  322   t  of the reticle. In some embodiments, the distance B is in a range of from 0.01 mm to 1 mm. 
     The carrier base  318  of one or more embodiments comprising the wall  323  extending from the top surface  318   t  does not require the carrier base assembly  302  to utilize a top shield as shown in  FIGS. 2-4 and 7  during a deposition process Elimination of the top shield, which in prior art designs and as shown in  FIG. 4  is placed above the surface of the reticle  322 , eliminates another source of particle generation. The top shield also tends to create non-uniform deposition due to an edge roll effect of material rolling from the edges of the top shield during deposition onto the reticle during a deposition process in a physical vapor deposition chamber. Thus, according to one or more embodiments of the disclosure, a carrier base assembly configured to hold an EUV reticle during a physical vapor deposition process consists essentially of, and in some embodiments consists of the carrier base comprising a wall extending from the top surface of carrier base. In specific embodiments, the carrier base assembly does not include a top shield resting on the top surface  318   t  of the carrier base  318  and surrounding the reticle. 
     According to one or more embodiments, each of the resting pins  378  having the domed surfaces  379  which contacts the reticle  322  bottom surface  322   b  are configured to be press fit on the carrier base  318  so that each resting pin  378  domed surface  379  protudes at a substantially equal distance P above the top surface  318   t  of the carrier base  318 . Thus, according to some embodiments, the carrier base  318  includes a plurality of resting pins  378  each resting pin  378  having a domed surface  379 , each of the resting pins  378  being spaced apart and configured so that the reticle  322  is substantially parallel with the carrier base top surface  318   t . Maintaining the reticle  322  substantially parallel with the top surface  318   t  is important to control uniformity and roughness of the deposition during a physical vapor deposition process. According to some embodiments, when the reticle  322  is substantially parallel to the top surface  318   t  of the carrier base  318 , there is less than 0.2 degrees of tilt of the reticle relative to a horizontal plane. 
     According to one or more embodiments, the carrier base  318  was redesigned to minimize and eliminate the openings in the prior art carrier base  218  shown in  FIG. 6 . It was determined that large openings and pockets provided sources of particle migration. Holes and pockets on prior art carrier base, which were source of particle migration to the reticle were eliminated or reduced in size. Instead of the large, open camera inspection openings  250 A and  250 D that had a substantially rectangular opening, smaller L-shaped camera pockets  327  (shown in  FIG. 10 ) are present on opposite corners of the wall  323  defining the containment region  329 . As can be seen in  FIG. 10 , the wall  323  forms a peripheral wall that defines the containment region  329  which contains the reticle  322 . A set of reticle pin openings  350 A sized to allow the reticle pins  330 A-C are placed adjacent the wall  323 . A second set of openings, namely resting pin openings,  350 B are provided for the resting pins to fit therethrough. With a camera above the assembly, this design eliminates various openings in the prior art carrier base  218 , which contributed to particle migration. With these camera openings eliminated and substantially reduced, particle migration is substantially reduced as well. 
     Referring to  FIGS. 14-16 , a reticle processing system  300  in use with carrier base  318  is shown according to one or more embodiments. As shown, the reticle processing system  300  (hereinafter “system”) includes a carrier assembly  302  coupled to and supported by a support assembly  304 . The support assembly  304  includes a plate  308  coupled to a frame  310  extending partially along a periphery of the plate  308 . As shown, the plate  308  is coupled to the frame  310  by a set of fasteners  312 A-C extending through openings of the frame  310 . Although not limited to any particular type, the fasteners  312 A-C may include nuts and bolts extending through the plate  308  and the frame  310 , wherein a spring  314  is provided around the bolt to provide flexibility/resiliency to the fasteners  312 A-C. As shown, the frame  310  has an L-shaped configuration and the plate  308  a hexagonal shape, thus permitting the support assembly  304  to be secured to a corner within a processing chamber. This configuration is non-limiting, as other geometries for the frame  310  and the plate  308  may be possible depending on the specific application and processing environment. 
     As shown, the carrier assembly  302  includes a carrier base  318  disposed below a reticle  322 . One will see that compared to the prior art system, there is no carrier top shield. In one or more embodiments, the reticle  322  is an EUV mask blank having an ultra-low thermal expansion substrate of glass, silicon, or other ultra-low thermal expansion material. The ultra-low thermal expansion materials may include fused silica, fused quartz, calcium fluoride, silicon carbide, silicon oxide-titanium oxide alloy, or other material having a thermal coefficient of expansion within the range of these materials. 
     The plate  308  of the system  300  includes a set of reticle pins  330 A-C, and a set of carrier base pins  332 A-C, each extending vertically, or generally vertically, from a top surface  334  of the plate  308 . The reticle pins  330 A-C, and carrier base pins  332 A-C are arranged in a pattern for supporting each component of the carrier base assembly  302 , while minimizing the number of contact points between the plurality of pins and the carrier assembly. 
     During operation, the support assembly  304  receives the carrier assembly thereupon. As the carrier base  318  is lowered on the plate  308 , the reticle pins  330 A-C extend through a corresponding first set of openings  350 A within the carrier base and engage the reticle  322 . As shown, the reticle pins  330 A-C generally extend vertically higher than the carrier base pins  332 A-C. Each of the reticle pins  330 A-C includes a domed upper face  354  engaging a bottom surface  358  of the reticle  322  to support the reticle  333  over the carrier base  318 . 
     The plurality of reticle pins  330 A-C, and carrier base pins  332 A-C support the carrier base assembly  302  and the reticle so the carrier base  318  at a bottom surface  364  thereof, and the reticle  322 , is supported and vertically separated from the carrier base  318 . During use, when the carrier base assembly  302  is placed on the support assembly  304 , the components of the carrier assembly are not in direct contact with one another. Specifically, the plurality of pins support the components of the carrier base assembly  302  in a way so the carrier base  318  is vertically separated from the plate  308  by a first gap  368 , the reticle  322  is vertically separated from the carrier base  318  by a second gap  370 . The placement and relative heights of the plurality of reticle pins  330 A-C and the carrier base pins  332 A-C, as well as the corresponding openings through the carrier base  318 , enable the demonstrated separation between components of the carrier assembly  302  when positioned atop the support assembly  304 . 
     As shown in  FIG. 15 , the system  300  may include a sensor system  380  configured to align the carrier assembly  302  to the support assembly  304 . For example, one or more sensors  382 A-C positioned are positioned above the support assembly  304  and used to verify whether each of the carrier base assembly components are correctly “in-position” on the support assembly  304 . This also prevents a user from inadvertently placing the carrier base assembly  302  or reticle  322  on the support assembly  304  if one is already in position. The sensors may transmit an output/feedback to a processor (not shown) of the sensor system  280  for subsequent analysis/processing. 
     During operation, the sensor system  380  is used in conjunction with a robot (not shown), such as a factory interface (H) robot, to accurately place the carrier base assembly  302 , including the reticle  322 , onto the carrier base assembly  302 , where the carrier base assembly  302  can be assembled or dis-assembled. Furthermore, the sensor system  380  positioned above the support assembly  304  is used to verify the carrier base assembly  302 , including the reticle  322 , are assembled correctly prior to being delivered to the loadlock. Advantageously, the robot is the sole moving component, ensuring the system  200  is not subject to unnecessary lifts or multiple robots, thus minimizing positional errors. For example, the vertical pick up and drop off trajectory of the robot is virtually identical, unlike when multiple, different lifts are employed. 
     As discussed above, and with reference to  FIG. 8 , which is a schematic view of a prior art carrier base  218  on a rotating pedestal  209  rotating about axis  217 , it is very difficult to obtain flatness across the bottom surface  218   b  of the prior art carrier base  218 , which results and friction (represented by arrows  211 ) between the pedestal and the bottom surface  218   b  of the carrier base  218  causing generation of particles  215  from deposited material  225  deposited in the gaps shown by arrows  213 . The prior art carrier base  218  has multiple gaps and openings (e.g., openings  242 A-C and openings  250 A-D) which are source of migration of particles  215  from the pedestal  209  to top of the reticle  222  through these openings as shown by the arrows  213 . 
     In specific embodiments, the resting pins  378  and the domed surfaces  379  comprise a material that dissipates static charge which prevents attraction of particles near the reticle  322 . In some embodiments, the resting pins  378  and domed surfaces  379  are made from a carbon filled thermoplastic polymer. In some embodiments, the carbon filled thermoplastic polymer comprises 20-40% by weight carbon, for example 30% by weight carbon. In specific embodiments, the pins and domed surfaces are made from carbon filed polyetheretherketone (PEEK), for example 20-40% carbon filled PEEK, such as 30% carbon filled PEEK. PEEK is a high performance thermoplastic that is tough, strong, rigid, and creep resistant. It offers excellent thermal, chemical, and hydrolysis resistance as well as excellent resistance to abrasion and dynamic fatigue. Its ability to run at high continuous temperature (480° F.) without permanent property loss and stable electrical properties makes PEEK a good alternative to fluoropolymers in hostile environments. In some embodiments, In specific embodiments, 30% Carbon Filled PEEK has been reinforced with carbon fibers that improve PEEK&#39;s compressive strength and stiffness, while also reducing its expansion rate. 
     The reticle pins  230 A-C are lifting pins are designed to create a gap between the carrier base  318  and the reticle  322  so that a robot arm can place and pick the reticle  322  during build of the carrier base assembly  302 . The reticle pins  230 A-C are made of the same or similar material as the resting pins  378  and domed surfaces  379 . 
     Turning now to  FIG. 17 , a flow diagram of a method for processing a reticle blank in accordance with certain aspects of the present disclosure is shown. In some embodiments, the methods may be implemented or instructed in part using a computer system. As such, the embodiments of the method may illustrate the functionality and/or operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, the blocks in the flowchart may represent a module, segment, or portion of code, comprising one or more executable instructions for implementing the specified logical function(s). As also noted, in some alternative implementations, the functions noted in the blocks might occur out of the order depicted in the figures. For example, two blocks shown in succession may, in fact, be executed concurrently. As also noted, the blocks of the methods  400  can be implemented by special purpose hardware-based systems for performing the specified functions or acts, or combinations of special purpose hardware and computer instructions. 
     In one embodiment, as shown in  FIG. 18  the method  400  may include providing a carrier base assembly consisting essentially of the carrier base as shown and described herein and a reticle blank, without a carrier top shield, as shown at block  401 . The method  400  may further include depositing the carrier base atop a support assembly, as shown at block  403 . In some embodiments, the support assembly includes a plate coupled to a frame. In some embodiments, the method  400  at block  403  includes depositing the carrier base assembly atop a plurality of pins extending from a top surface of the plate, wherein the plurality of pins support the carrier base assembly so the carrier base is vertically separated from the plate by a first gap, and the reticle blank is vertically separated from the carrier base by a second gap. 
     In some embodiments, the method  400  at block  403  may further include identifying a position of the carrier assembly using a sensor system positioned above the support assembly, and depositing the carrier base assembly atop the support assembly according to the identified position of the carrier assembly. 
     In some embodiments, the method  400  at block  403  may further include providing a set of reticle pins extending from the top surface of the plate through a first set of openings in the carrier base. The method  400  at block  403  further includes the set of reticle pins supporting the reticle over the carrier base. The method  400  at block  403  further includes providing a set of carrier base pins extending from the top surface of the plate, wherein the set of carrier base pins is in contact with the carrier base to support the carrier base over the plate. The set of carrier base pins and set of reticle pins are positioned adjacent a wall defining a containment region, the wall extending from a top surface of the carrier base, eliminating the need for a carrier top shield. The method  400  further includes depositing the reticle blank within a containment region of the carrier base defined by the wall as shown at block  405 . In some embodiments, the reticle blank is deposited atop the set of reticle pins extending from the plate. 
     The method  400  further includes removing the carrier assembly from the support assembly, as shown at block  407 . In some embodiments, a robot including a robot blade is positioned within the first gap formed between plate and the carrier base, and the carrier assembly is then lifted upwards from the support assembly, thus causing the carrier base, and the reticle blank to compress and engage one another. The robot may then transport the carrier base assembly for further processing. In some embodiments, the carrier base assembly is placed onto a pedestal of a physical deposition chamber, where one or more layers are deposited by physical vapor deposition onto the reticle. 
     Reference throughout this specification to “one embodiment,” “certain embodiments,” “one or more embodiments” or “an embodiment” means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. Thus, the appearances of the phrases such as “in one or more embodiments,” “in certain embodiments,” “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily referring to the same embodiment of the disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments. 
     In further embodiments, the method step  401  shown in  FIG. 18  includes a sequence of building a carrier base assembly which comprises orienting the carrier at an aligner station after it is picked up based on a position of notch. The carrier base is then inspected by a camera to check its orientation and placement. The carrier base and then moved to the system  300  described herein for assembly at  403 . The reticle is then picked up and placed onto lifting pins by a separate robot blade (a reticle blade) as shown at  405 . At  407 , the carrier base blade picks up the entire assembly, which can be inspected at an inspection station prior to deposition, such as physical vapor deposition in a physical vapor deposition chamber. 
     Although the disclosure herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the method and apparatus of the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure include modifications and variations that are within the scope of the appended claims and their equivalents.