Abstract:
A method and apparatus for loading substrates in an inspection station is disclosed herein. In one embodiment a loading module for a substrate inspection station is disclosed herein. The loading module includes two arms, a plurality of substrate grippers, two rotatable support members, a conveyor, and at least one actuator. Each arm has a first end and a second end, wherein the second end is opposite the first end. Each substrate gripper is disposed at a respective end of each arm. Each rotatable support member is coupled to a respective one of the arms. The conveyor is disposed between the rotatable support members. The at least one actuator is configured to rotate the arms about the rotatable support members to selectively position the grippers over the conveyor in a location that allows a substrate held by the gripper to be released onto the conveyor.

Description:
FIELD 
       [0001]    Embodiments of the present disclosure generally relate to substrate loading equipment. More specifically, embodiments disclosed herein relate to a system and method for loading substrates into semiconductor inspection equipment. 
       BACKGROUND 
       [0002]    Substrates, such as semiconductor substrates, are routinely inspected during processing at independent inspection stations to ensure compliance with predetermined quality control standards. Different inspection techniques provide comprehensive data regarding products and processes. However, comprehensive inspections can be time consuming, thus reducing throughput, due to the number of inspection stations required and the resulting transfer time of moving substrates therebetween. Thus, device manufacturers are often faced with the decision of choosing between thorough inspection stations with burdensome inspection/transfer times, or foregoing certain inspection processes. 
         [0003]    However, as inspection processes have continued to decrease the amount of time required to complete required inspection steps, loading apparatuses also need to be improved to be able to keep up with the increased throughput. 
         [0004]    Thus, there is a need for an proved substrate loading apparatus for use with inspection systems. 
       SUMMARY 
       [0005]    In one embodiment, a loading module for a substrate inspection system is disclosed herein. The loading module includes two arms, a plurality of grippers, two rotatable support members, a conveyer, and at least one actuator. Each arm has a first end and a second end, wherein the second end is opposite the first end. Each substrate ripper is disposed at a respective end of each arm. Each rotatable support member is coupled to a respective one of the arms. The conveyor is disposed between the rotatable support members. The at least one actuator is configured to rotate the arms about the rotatable support members to selectively position the grippers over the conveyor in a location that allows a substrate held by the gripper to be released onto the conveyor. 
         [0006]    In another embodiment, a loading module for a substrate inspection system is disclosed herein. The loading module includes a conveyor, two cassette holders disposed on opposite sides of the conveyor, two arms, two rotatable support members, and two actuators. Each arm includes a first end, a second end opposite the first end, a first gripper disposed on the first end of the first arm, and a second gripper disposed on the second end of the second arm. Each rotatable support member is coupled to one of the arms. Each actuator is coupled to a respective rotatable support member. The actuators are configured to rotate the arms about the rotatable support members such that the arms rotate in an indexing fashion between positions that allow the grippers to transfer substrates between the cassette holders and the conveyor. 
         [0007]    In another embodiment, a method for loading substrates is disclosed herein. The method includes rotating a first arm a predetermined amount in a first direction to pick up a first substrate, rotating the first arm in the first direction and rotating a second arm a predetermined amount in a second direction, wherein the second direction is opposite the first direction, and continuing to rotate the first arm in the first direction and the second arm in the second direction in a stepping fashion to alternately pick up and load substrates. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    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 typical 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. 
           [0009]      FIG. 1  is a schematic top view of an inspection system having one embodiment of a loading module. 
           [0010]      FIG. 2  is a side view of an arm of the loading module plurality of grippers, according to one embodiment. 
           [0011]      FIG. 3  is a bottom perspective view of the gripper having a Bernoulli vacuum nozzle, according to one embodiment. 
           [0012]      FIG. 4  is a flow diagram of one embodiment of a method for loading substrates in a loading module. 
           [0013]      FIGS. 5A-5E  illustrate the loading module at different stages of the method of  FIG. 4 , according to one embodiment. 
       
    
    
       [0014]    For clarity, identical reference numerals have been used, where applicable, to designate identical elements that are common between figures. Additionally, elements of one embodiment may be advantageously adapted for utilization in other embodiments described herein. 
       DETAILED DESCRIPTION 
       [0015]      FIG. 1  illustrates a top plan view of a substrate inspection system  100 , according to one embodiment. The inspection system  100  includes a loading module  102 , a modular unit  104 , and a sorting unit  106 . In one embodiment, the modular unit  104  may include one or more metrology stations. The metrology stations may include, by way of example only, any of the following: a micro-crack inspection unit, a thickness measuring unit, a resistivity measuring unit, a photoluminescence unit, a geometry inspection unit, a saw mark detection unit, a stain detection unit, a chip detection unit, and/or a crystal fraction detection unit. The micro-crack inspection unit may be, by way of example only, configured to inspect substrates for cracks, as well as to optionally determine crystal fraction of a substrate. The geometry inspection unit may be configured, by way of example only, to analyze surface properties of a substrate. The saw mark detection unit may be configured, by way of example only, to identify saw marks including groove, step, and double step marks on a substrate. The metrology stations may also include other examples beyond those listed. 
         [0016]    The loading module  102 , the modular unit  104 , and the sorting unit  106  are connected in a linear arrangement such that a substrate may be easily and rapidly passed among the loading module  102 , the modular unit  104 , and the sorting unit  106  by a conveyor system  108  without exiting the inspection system  100 . The loading module  102  is configured to load substrates for transfer through the modular unit  104  and the sorting unit  106  by a conveyor system  108 . 
         [0017]    The loading module  102  receives one or more cassettes  110 ,  111  containing substrates  112  in a stacked configuration. Each cassette  110 ,  111  include a plurality of slots therein. Each slot is configured to hold a substrate  112 . The cassettes  110 ,  111  may be positioned such that the substrates  112  are positioned one over the other. In another example, the substrates  112  may be positioned in a holder such that there is no gap between each substrate  112 . The substrates  112  are transferred from the cassettes  110 ,  111  to the conveyor system  108 . The cassette  110  is positioned in a cassette holder  190 . The cassette  111  is positioned in a cassette holder  192 . In one embodiment, the conveyor system  108  may be a continuous conveyor belt running through the inspection system  100 . In another embodiment, the conveyor system  108  may include more than one conveyor belt running through the inspection system  100 . The one or more conveyor belts may be disposed sequentially in a linear arrangement to transfer substrates received in the loading module  102  to the modular unit  104 . 
         [0018]    The loading module  102  includes a plurality of arms (shown for example as arms  114 ,  115 ), a plurality of rotatable support members  125 ,  126 , and at least one actuator  116  for rotating the arms  114 ,  115 . The arm  114  includes a first end  118  and a second end  120  opposite the first end  118 . The arm  114  is coupled to the rotatable support member  125  at a point located about midway between the ends  118 ,  120  of the arm  114 . The rotatable support member  125  is configured to rotate the arm  114  about an axis  128  passing through the point. The arm  114  may be seen in more detail in  FIG. 2 . 
         [0019]    The arm  115  includes a first end  122  and a second end  124  opposite the first end  122 . The arm  115  is coupled to the rotatable support member  126  at a point located about midway between the ends  122 ,  124  of the arm  115 . The rotatable support member  126  is configured to rotate the arm  115  about an aids  129  passing through the point. 
         [0020]    The rotatable support members  125 ,  126  are positioned on opposite sides of the conveyor system  108 . The rotatable support member  125  is positioned between the conveyor system  108  and the cassette  110 . The rotatable support member  126  is positioned between the conveyor system  108  and the cassette  111 . The rotatable support member  125  is positioned to allow the ends  118  of the arm  114  to be selectively positioned over the cassette  110  and the end  120  of the arm  114  to be selectively positioned over the conveyor system  108  to facilitate transfer of substrates therebetween. Likewise, the rotatable support member  126  is positioned to allow the end  122  of the arm  115  to be selectively positioned over the cassette  111  and the end  124  of the arm  115  to be selectively positioned over the conveyor system  108  to facilitate transfer of substrates therebetween. 
         [0021]    A substrate gripper  123  is disposed on each end  118 ,  120 ,  122 ,  124  of the arms  114 , 115 . The gripper  123  may be disposed on a bottom side or end of each of the arms  114 ,  115  to allow the gripper  123  to secure a substrate  112  for transfer. The gripper  123  may be any suitable substrate gripper, such as a suction gripper, a claw gripper, a magnetic gripper, a Bernoulli vacuum nozzle, and the like. Each cassette  110 ,  111  may include an elevator (not shown) configured to raise the substrates to a position such that the top most substrate may be grabbed by the substrate gripper  123 . 
         [0022]      FIG. 3  is an isometric bottom view of the gripper  123  having a Bernoulli vacuum nozzle  200 . Bernoulli vacuum note  200  The Bernoulli vacuum nozzle  200  enables gripping of the substrate with reduced contact, thus advantageously reducing potential damage to the substrate during handling. The Bernoulli vacuum nozzle  200  may be operated to provide non-contact transfer of the substrate  112  by applying airflow under the substrate  112  in a manner that create a vacuum and lift forces between a center and a circumference of the substrate  112 . Due to the vacuum force and the continuous airflow, the substrate  112  does not attach to the Bernoulli vacuum nozzle  200 , but rather holds that substrate  112  against one or more stops  290 . The stops  290  may be configured as a post or other suitable geometry. The stops  290  may extend from the arm  114  a distance greater than that of the Bernoulli vacuum nozzle  200  to ensure that the substrate  112  does not contact the Bernoulli vacuum nozzle  200  during operation. Ends of stops  290 , which contact the substrate  112 , may be made of a material selected to provide sufficient friction between the substrate  112  and stop  290  to ensure that the substrate  112  does not shift or slide while the arm  114  is rotated. Thus, the gripper  123  having the Bernoulli vacuum nozzle  200  enables the safe handling of the substrate  112  within the loading module  102 . 
         [0023]    Referring back to  FIG. 1 , the rotatable support members  125 ,  126  may be coupled to the at least one actuator  116 . In one embodiment, the support members  125 ,  126  are coupled to the same actuator  116 . In another embodiment, each support member  125 ,  126  is coupled to separate actuators  116 . As discussed above, the actuator  116  is configured to rotate the arms  114 ,  116  about the support members  125 ,  126 . In one embodiment, the actuator  116  is a stepper motor, a servo motor, a rotary actuator, an air motor or device suitable. The actuator  116  may rotate the rotatable support members  125 ,  126  in indexing fashion, such that with each motion of the arms  114 ,  115 , a new substrate is received from one of the cassettes  110 ,  111  by one end of the arms  114 ,  115  while the opposite end of the arm  114 ,  115  is transferring a substrate to the same position on the conveyor system  108 . 
         [0024]    The inspection system  100  may further include a controller  130 . The inspection system  100  is coupled to the controller  130  by a communication cable  132 . The controller  130  is operable to control processing of a substrate within the inspection system  100 . The controller  130  includes a programmable central processing unit (CPU)  134  that is operable with a memory  136  and a mass storage device, an input control unit, and a display unit (not shown), such as power supplies, clocks, cache, input/output (I/O) circuits, and the like, coupled to the various components of the inspection system  100  to facilitate control of the processes of handling and inspecting the substrates. The controller  130  may also include hardware for monitoring the processing of a substrate through sensors (not shown) in the inspection system  100 . 
         [0025]    To facilitate control of the inspection system  100  and processing a substrate, the CPU  134  may be one of any form of general-purpose computer processors for controlling the substrate process. The memory  136  is coupled to the CPU  134  and the memory  136  is non-transitory and may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk drive, hard disk, or any other form of digital storage, local or remote. Support circuits  138  are coupled to the CPU  134  for supporting the CPU  134  in a conventional manner. The process for loading substrates by operation of the loading module  102  may be stored in the memory  136 . The process for loading substrates may also be stored and/or executed by a second CPU (not shown) that is remotely located from the hardware being controlled by the CPU  134 . 
         [0026]    The memory  136  is in the form of computer-readable storage media that contains instructions, that when executed by the CPU  134 , facilitates the operation of the inspection system  100 . The instructions in the memory  136  are in the form of a program product such as a program that implements the operation of the inspection system  100 , for example, the method  400  of  FIG. 4 , including for example the operation of the loading module  102 . The program code may conform to any one of a number of different programming languages. In one example, the disclosure may be implemented as a program product stored in computer readable storage media for use with a computer system. The program(s) of the program product define functions of the embodiments. Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, flash memory, ROM chips or any tope of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writing storage media (e.g. floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored. Such computer-readable storage media, when carrying computer-readable instructions that direct the functions of the methods described herein, are embodiments of the present disclosure. 
         [0027]      FIG. 4  illustrates a flow diagram of a method  400  of loading substrates  112  onto the conveyor system  108  in the loading module  102 , according to one embodiment. The method  400  rotates the arms  114 ,  115  in an indexing fashion such that the arms  114 ,  115  simultaneously pick-up one substrate from a cassette  110 ,  111  and load another substrate onto the conveyor system  108 . The loading module  102  at different stages of method  400  are illustrated in  FIGS. 5A-5E .  FIG. 5A  shows the arms  114 ,  115  in their initial positions. 
         [0028]    Method  400  begins at block  402 . At block  402 , an arm of the loading module is rotated a predetermined amount in a first direction, such that an end of the arm is positioned over a first substrate disposed in one of the cassettes. The gripper disposed at the end of the first arm that is positioned over the cassette picks up the first substrate. For example,  FIG. 5B  illustrates the first arm  114  rotated 90 degrees clockwise such that the first end  118  of the first arm  114  is positioned over the cassette  110 . The gripper  123  disposed at the first end  118  of the first arm  114  picks up a first substrate  112   a.    
         [0029]    At block  404 , the first arm  114  is rotated a predetermined amount in the first direction such that the end of the arm is no longer positioned over the cassette and the conveyor system. The second arm  115  is rotated a predetermined amount in a second direction such that an end of the arm is positioned over a second substrate disposed in the cassette  111 . The second direction in which the second arm moves is opposite the first direction in which the first arm moves. By moving the arms  114 ,  115  in opposite directions, the potential for contact between substrates held on the arms is reduced. The gripper disposed on the end of the second arm that is positioned over the cassette picks up a second substrate. In one embodiment, the arms  114 ,  115  are connected to the same actuator. When the arms are connected to the same actuator, the likelihood of the arms colliding is minimized because synchronization of the motion of the arms is ensured. In another embodiment, each arm is connected to a separate actuator. The controller controls the actuators such that the rotation of the arms is timed to prevent the arms or substrates held thereon from colliding. For example,  FIG. 5C  illustrates the first arm  114  rotated 90 degrees clockwise and the second arm  115  rotated 90 degrees counter clockwise. The first arm  114  is in a position substantially perpendicular to the position shown in  FIG. 5B  to allow the gripper  123  of the second arm  115  to rotate and pick up a second substrate  112   b  from the cassette  111 . The first end  122  of the second arm  115  is positioned over the cassette  111 . The second end  124  of the second arm  115  is positioned over the conveyor system  108 . 
         [0030]    At block  406 , the second arm is rotated a predetermined amount in the second direction, such that the ends of the arm are no longer positioned over the cassette and the conveyor system. The first arm is rotated a predetermined amount in the first direction, such that the end not holding the first substrate is positioned over the cassette. The end of the first arm holding the first substrate is positioned over the conveyor system. The gripper disposed on the end of the first arm holding the first substrate releases the substrate onto the conveyor system. The gripper disposed on the end positioned over the cassette picks up a third substrate. For example,  FIG. 5D  illustrates the first arm  114  rotated 90 degrees clockwise and the second arm  115  rotated 90 degrees counter clockwise. The first arm  114  is in a position substantially perpendicular to the position shown in  FIG. 5C  such that the first end  118  of the first arm  114  is positioned over the conveyor system  108  and the second end  120  of the first arm  114  is positioned over the cassette  110 . The gripper  123  disposed on the first end  118  of the first arm  114  is holding the first substrate  112   a  picked up in  FIG. 5B . The gripper  123  disposed on the first end  118  of the first arm  114  releases the substrate  112   a  such that the substrate  112   a  is loaded onto the conveyor system  108 . The gripper  123  disposed on the second end  120  of the first arm  114  picks up a third substrate  112   c  from the cassette  110 . The second arm  115  is in a position substantially perpendicular to the position of the second arm  115  shown in  FIG. 5C  to allow rotation of the first arm  114  without any collisions. 
         [0031]    At block  408 , the first arm is rotated a predetermined amount in the first direction, such that the ends of the arm are no longer positioned over the cassette and the conveyor system. The second arm is rotated a predetermined amount in the second direction, such that the end not holding the second substrate is positioned over the cassette. The end of the second harm holding the second substrate is positioned over the conveyor system. The gripper  123  disposed on the end of the second arm holding the second substrate releases the substrate onto the conveyor system. The gripper  123  disposed on the end positioned over the cassette picks up a fourth substrate. For example,  FIG. 5E  illustrates the first arm  114  rotated 90 degrees clockwise and the second arm  115  rotated 90 degrees counterclockwise. The second arm  115  is in a position substantially perpendicular to the position shown in  FIG. 5D , such that the first end  122  of the second arm  115  is positioned over the conveyor system  108  and the second end  124  of the second arm  115  is positioned over the cassette  111 . The gripper  123  disposed on the first end  122  of the second arm  115  is holding the second substrate  112   b  picked up in  FIG. 4B . The gripper  123  disposed on the first end  122  of the second arm  115  releases the substrate  112   b  such that the substrate  112   b  is loaded onto the conveyor system  108 . The gripper  123  disposed on the second end  124  of the second arm  115  positioned over the cassette  111  picks up the fourth substrate  112   d.  The first arm  114  is in a position substantially perpendicular to the position of the first arm  114  shown in  FIG. 5D  to allow rotation of the second arm  115  without any collisions. 
         [0032]    Method  400  may continue in this matter until all substrates from the cassettes  110 ,  111  are loaded onto the conveyor system  108 . Method  400  allows for the advantageous loading in excess of 5000 substrates per hour, which is a significant improvement over conventional inspection systems. 
         [0033]    It will be appreciated to those skilled in the art that the preceding examples are exemplary and not limiting. It is intended that all permutations, enhancements, equivalents, and improvements thereto that are apparent to those skilled in the art upon a reading of the specification and a study of the drawings are included within the true spirit and scope of the present disclosure. It is therefore intended that the following appended claims include all such modifications, permutations, and equivalents as fall within the true spirit and scope of these teachings.