Control system and method for improving tracking accuracy of a stage through processing of information from previous operations

Abstract

A precision assembly ( 10 ) includes a stage assembly ( 220 ) having a first stage ( 208 ), a first mover assembly ( 210 ) and a control system ( 24 ). The first mover assembly ( 210 ) moves the first stage ( 208 ) during a first iteration ( 300 ) and a subsequent second iteration ( 302 ) having a similar movement to the first iteration ( 300 ). The first iteration ( 300 ) generates positioning data that is sent to the control system ( 24 ) to control the first mover assembly ( 210 ) to adjust movement of the first stage ( 208 ) during the second iteration ( 302 ) based on at least a portion of the positioning data from the first iteration ( 300 ). The positioning data can include the position of the first stage ( 208 ) along a first axis, a second axis and/or a third axis. The stage assembly can also include a second stage ( 206 ) and a second mover assembly ( 204 ) that moves the second stage ( 206 ) synchronously with the first stage ( 208 ). The second stage ( 206 ) generates positioning data that is used by the control system ( 24 ) to adjust movement the first mover assembly ( 210 ) of the first stage ( 208 ) to improve synchronization of movement of the stages. The precision assembly ( 10 ) can also include one or more sensors ( 23 ) that monitor movement of one or more components of the precision assembly ( 10 ) other than the stage assembly ( 220 ). Positioning data of such movement is sent to the control system ( 24 ) to control movement of the first stage ( 208 ).

What is claimed is:  
     
         1 . A stage assembly comprising: 
 a first stage;    a first mover assembly that moves the first stage during a first iteration and a subsequent second iteration, the first iteration having a first intended trajectory of the first stage, the second iteration having a second intended trajectory of the first stage that is similar to the first intended trajectory of the first stage, positioning data being generated during the first iteration; and    a control system that receives the positioning data, the control system controlling the first mover assembly to adjust movement of the first stage during the second iteration based on at least a portion of the positioning data.    
     
     
         2 . The stage assembly of  claim 1  wherein the control system includes a memory buffer that stores the positioning data.  
     
     
         3 . The stage assembly of  claim 1  wherein movement of the first stage includes movement along a first axis and wherein the positioning data includes the position of the first stage along the first axis.  
     
     
         4 . The stage assembly of  claim 3  wherein movement of the first stage includes movement along a second axis that is orthogonal to the first axis, and wherein the positioning data includes the position of the first stage along the second axis.  
     
     
         5 . The stage assembly of  claim 4  wherein movement of the first stage includes movement about a third axis that is orthogonal to the first and second axes, and wherein the positioning data includes the position of the first stage about the third axis.  
     
     
         6 . The stage assembly of  claim 1  wherein movement of the first stage includes movement about a first axis, and wherein the positioning data includes the position of the first stage about the first axis.  
     
     
         7 . The stage assembly of  claim 1  wherein at a time t1 1  during the first iteration the first stage has an intended position and an actual position, wherein the difference between the intended position and the actual position at time t1 1  is a t1 1  following error, and wherein the positioning data includes the t1 1  following error.  
     
     
         8 . A precision apparatus including the stage assembly of  claim 7 , the precision apparatus further comprising a second stage assembly having a second stage and a second mover assembly that moves the second stage synchronously with the first stage, wherein the positioning data includes second stage positioning information, the control system adjusting movement of the first mover assembly based at least partly on the second stage positioning information to improve synchronization of movement of the stages.  
     
     
         9 . The precision apparatus of  claim 8  wherein the second stage moves during a first iteration and a subsequent second iteration, the first iteration of the second stage having a first intended trajectory, the second iteration of the second stage having a second intended trajectory that is similar to the first intended trajectory of the second stage, and wherein the positioning data includes second stage positioning information during the first iteration of the second stage.  
     
     
         10 . The stage assembly of  claim 7  wherein at a time t2 1  during the first iteration the first stage has an intended position and an actual position, wherein the difference between the intended position and the actual position at time t2 1  is a t2 1  following error, and wherein the positioning data includes the t2 1  following error.  
     
     
         11 . The stage assembly of  claim 1  wherein the first stage moves along an actual trajectory during the first iteration, and wherein the positioning data includes at least a portion of the actual trajectory of the first stage during the first iteration.  
     
     
         12 . The stage assembly of  claim 1  wherein the control system includes a noise filter that is applied to the positioning data to remove the high frequency noise from the positioning data.  
     
     
         13 . The stage assembly of  claim 1  wherein control system updates the positioning data using an adaptive algorithm.  
     
     
         14 . The stage assembly of  claim 13  wherein the control system selectively pauses updating of the positioning data.  
     
     
         15 . The stage assembly of  claim 13  wherein the updated positioning data is used in a model-based control law.  
     
     
         16 . The stage assembly of  claim 1  wherein the control system includes a non-model based control law that is applied to the positioning data.  
     
     
         17 . The stage assembly of  claim 1  wherein the first mover assembly moves the first stage in a third iteration that precedes the first iteration, wherein positioning data is generated from the third iteration, and wherein the control system controls the first mover assembly to adjust movement of the first stage during the second iteration based on the positioning data generated during the third iteration.  
     
     
         18 . The stage assembly of  claim 1  wherein the first iteration and the second iteration each have substantially similar points in time within each corresponding iteration that include time t1, time t2 and time t3, wherein time t1 is prior to time t2, and time t2 is prior to time t3, and wherein the control system controls the first mover assembly to adjust movement of the first stage at time t2 of the second iteration based on the positioning data generated at time t3 of the first iteration.  
     
     
         19 . The stage assembly of  claim 18  wherein the control system controls the first mover assembly to adjust movement of the first stage at time t2 of the second iteration based on the positioning data generated at time t2 of the first iteration.  
     
     
         20 . The stage assembly of  claim 1  wherein the second intended trajectory of the first stage is identical to the first intended trajectory of the first stage.  
     
     
         21 . The stage assembly of  claim 1  wherein the first stage is a reticle stage that retains a reticle.  
     
     
         22 . The stage assembly of  claim 1  wherein the first stage is a wafer stage that retains a wafer.  
     
     
         23 . A precision assembly including an illumination source and the stage assembly of  claim 1  positioned near the illumination source.  
     
     
         24 . The precision assembly of  claim 23  further comprising a sensor that senses the movement of a portion of the exposure apparatus other than the stage assembly, wherein the positioning data includes the movement of the portion of the exposure apparatus being monitored by the sensor.  
     
     
         25 . The precision assembly of  claim 24  wherein the portion of the exposure apparatus is at least a portion of an optical assembly.  
     
     
         26 . The precision assembly of  claim 24  wherein the portion of the exposure apparatus is at least a portion of an apparatus frame.  
     
     
         27 . A device manufactured with the precision assembly according to  claim 23 .  
     
     
         28 . A wafer on which an image has been formed by the precision assembly according to  claim 23 .  
     
     
         29 . A precision assembly comprising: 
 a first stage assembly including a first stage and a first mover assembly that moves the first stage;    a second stage assembly including a second stage and a second mover assembly that moves the second stage synchronously with the first stage, positioning data being generated that includes the position of the second stage; and    a control system that receives the positioning data, the control system controlling the first mover assembly to adjust movement of the first stage based on the position of the second stage to improve synchronization of movement of the stages.    
     
     
         30 . The precision assembly of  claim 29  wherein the control system includes a memory buffer that stores the positioning data.  
     
     
         31 . The precision assembly of  claim 29  wherein the control system includes a noise filter that is applied to the positioning data to remove the high frequency noise from the positioning data.  
     
     
         32 . The precision assembly of  claim 29  wherein control system updates the positioning data using an adaptive algorithm.  
     
     
         33 . The precision assembly of  claim 32  wherein the control system selectively pauses updating of the positioning data.  
     
     
         34 . The precision assembly of  claim 32  wherein the updated positioning data is used in a model-based control law.  
     
     
         35 . The precision assembly of  claim 29  wherein the control system includes a non-model based control law.  
     
     
         36 . The precision assembly of  claim 29  wherein the first stage is a reticle stage that retains a reticle, and wherein the second stage is a wafer stage that retains a wafer.  
     
     
         37 . The precision assembly of  claim 29  wherein the first mover assembly moves the first stage during a first iteration and a subsequent second iteration having a similar movement to the first iteration of the first stage, at least a portion of the positioning data being generated from the first iteration of the first stage, and wherein the control system controls the first mover assembly during the second iteration of the first stage based on at least a portion of the positioning data that is generated from the first iteration of the first stage.  
     
     
         38 . The precision assembly of  claim 37  wherein the second mover assembly moves the second stage during a first iteration and a subsequent second iteration having a similar movement to the first iteration of the second stage, at least a portion of the positioning data being generated from the first iteration of the second stage, and wherein the control system controls the second mover assembly during the second iteration of the second stage based on at least a portion of the positioning data that is generated from the first iteration of the second stage.  
     
     
         39 . The precision assembly of  claim 37  wherein at a time t2 1  during the first iteration the first stage has an intended position and an actual position, wherein the difference between the intended position and the actual position at time t2 1  is a t2 1  following error, and wherein the positioning data includes the t2 1  following error.  
     
     
         40 . The precision assembly of  claim 37  wherein the first stage moves along an actual trajectory during the first iteration, and wherein the positioning data includes at least a portion of the actual trajectory of the first stage during the first iteration.  
     
     
         41 . The precision assembly of  claim 37  wherein the first mover assembly moves the first stage in a third iteration that precedes the first iteration, wherein positioning data is generated from the third iteration, and wherein the control system controls the first mover assembly to adjust movement of the first stage during the second iteration based on the positioning data generated from the third iteration.  
     
     
         42 . The precision assembly of  claim 37  wherein the first iteration and the second iteration each have substantially similar points in time within each corresponding iteration that include time t1, time t2 and time t3, wherein time t1 is prior to time t2, and time t2 is prior to time t3, and wherein the control system controls the first mover assembly to adjust movement of the first stage at time t2 of the second iteration based on the positioning data generated at time t3 of the first iteration.  
     
     
         43 . The precision assembly of  claim 42  wherein the control system controls the first mover assembly to adjust movement of the first stage at time t2 of the second iteration based on the positioning data generated at time t2 of the first iteration.  
     
     
         44 . The precision assembly of  claim 42  wherein the control system controls the first mover assembly to adjust movement of the first stage at time t2 of the second iteration based on the positioning data generated at times t1 and t2 of the first iteration.  
     
     
         45 . The precision assembly of  claim 29  wherein the control system includes a noise filter that is applied to the positioning data to remove the high frequency noise from the positioning data.  
     
     
         46 . The precision assembly of  claim 29  wherein control system updates the positioning data using an adaptive algorithm.  
     
     
         47 . The precision assembly of  claim 46  wherein the control system selectively pauses updating of the positioning data.  
     
     
         48 . The precision assembly of  claim 46  wherein the updated positioning data is used in a model-based control law.  
     
     
         49 . The precision assembly of  claim 29  wherein the control system includes a non-model based control law.  
     
     
         50 . The precision assembly of  claim 29  further comprising a sensor that senses the movement of a portion of the exposure apparatus other than the stage assembly, wherein the positioning data includes the movement of the portion of the exposure apparatus being monitored by the sensor.  
     
     
         51 . The precision assembly of  claim 50  wherein the portion of the precision assembly is at least a portion of an optical assembly.  
     
     
         52 . The precision assembly of  claim 50  wherein the portion of the precision assembly is at least a portion of an apparatus frame.  
     
     
         53 . A device manufactured with the preision assembly according to  claim 29 .  
     
     
         54 . A wafer on which an image has been formed by the precision assembly according to  claim 29 .  
     
     
         55 . A precision assembly comprising: 
 a first stage assembly including a first stage and a first mover assembly that moves the first stage;    a sensor that monitors the position of a portion of the precision assembly other than the stage assembly, the sensor providing positioning data including the position of the portion of the precision assembly being monitored by the sensor; and    a control system that receives the positioning data, the control system controlling the first mover assembly to adjust movement of the first stage based on at least a portion of the positioning data.    
     
     
         56 . The precision assembly of  claim 55  wherein the portion of the precision assembly being monitored by the sensor includes at least a portion of an optical assembly.  
     
     
         57 . The precision assembly of  claim 55  wherein the portion of the precision assembly being monitored by the sensor includes at least a portion of an apparatus frame.  
     
     
         58 . The precision assembly of  claim 55  wherein the precision assembly includes a second stage assembly having a second stage and a second mover assembly that moves the second stage synchronously with the first stage, wherein the positioning data includes the position of the first and second stages, and wherein the control system controls at least one of the mover assemblies to adjust movement of the first stage based on the positioning data to improve synchronization of movement of the stages.  
     
     
         59 . The precision=assembly=of  claim 58  wherein the second mover assembly moves the second stage during a first iteration and a subsequent second iteration having a similar movement to the first iteration of the second stage, at least a portion of the positioning data being generated during the first iteration of the second stage, and wherein the control system controls the second mover assembly during the second iteration of the second stage based on at least a portion of the positioning data that is generated during the first iteration of the second stage.  
     
     
         60 . The precision assembly of  claim 58  wherein the first stage is a reticle stage that retains a reticle, and wherein the second stage is a wafer stage that retains a wafer.  
     
     
         61 . The precision assembly of  claim 55  wherein the first mover assembly moves the first stage during a first iteration and a subsequent second iteration having a similar movement to the first iteration of the first stage, at least a portion of the positioning data being generated from the first iteration of the first stage, and wherein the control system controls the first mover assembly during the second iteration of the first stage based on at least a portion of the positioning data that is generated during the first iteration of the first stage.  
     
     
         62 . The precision assembly of  claim 61  wherein at a time t2 1  during the first iteration the first stage has an intended position and an actual position, wherein the difference between the intended position and the actual position at time t2 1  is a t2 1  following error, and wherein the positioning data includes the t2 1  following error.  
     
     
         63 . The precision assembly of  claim 62  wherein the first stage moves along an actual trajectory during the first iteration, and wherein the positioning data includes at least a portion of the actual trajectory of the first stage during the first iteration.  
     
     
         64 . The precision assembly of  claim 61  wherein the first mover assembly moves the first stage in a third iteration that precedes the first iteration, wherein positioning data is generated from the third iteration, and wherein the control system controls the first mover assembly to adjust movement of the first stage during the second iteration based on the positioning data generated from the third iteration.  
     
     
         65 . The precision assembly of  claim 61  wherein the first iteration and the second iteration each have substantially similar points in time within each corresponding iteration that include time t1, time t2 and time t3, wherein time t1 is prior to time t2, and time t2 is prior to time t3, and wherein the control system controls the first mover assembly to adjust movement of the first stage at time t2 of the second iteration based on the positioning data generated at time t3 of the first iteration.  
     
     
         66 . The precision assembly of  claim 65  wherein the control system controls the first mover assembly to adjust movement of the first stage at time t2 of the second iteration based on the positioning data generated at time t2 of the first iteration.  
     
     
         67 . The precision assembly of  claim 65  wherein the control system controls the first mover assembly to adjust movement of the first stage at time t2 of the second iteration based on the positioning data generated at times t1 and t2 of the first iteration.  
     
     
         68 . The precision assembly of  claim 55  wherein the control system includes a noise filter that is applied to the positioning data to remove the high frequency noise from the positioning data.  
     
     
         69 . The precision assembly of  claim 55  wherein control system updates the positioning data using an adaptive algorithm.  
     
     
         70 . The precision assembly of  claim 69  wherein the control system selectively pauses updating of the positioning data.  
     
     
         71 . The precision assembly of  claim 69  wherein the updated positioning data is used in a model-based control law.  
     
     
         72 . The precision assembly of  claim 55  wherein the control system includes a non-model based control law.  
     
     
         73 . A device manufactured with the precision assembly according to  claim 55 .  
     
     
         74 . A wafer on which an image has been formed by the precision assembly according to  claim 55 .  
     
     
         75 . A method for positioning one or more stages of a precision assembly, the method comprising the steps of: 
 moving the first stage during a first iteration and a subsequent second iteration with a first mover assembly, the second iteration having a similar movement to the first iteration;    generating positioning data from the first iteration that is sent to a control system; and    controlling the first mover assembly with the control system to adjust movement of the first stage during the second iteration based on at least a portion of the positioning data.    
     
     
         76 . The method of  claim 75  wherein the step of generating positioning data includes sending the positioning data to a memory buffer that stores the positioning data.  
     
     
         77 . The method of  claim 76  wherein the step of generating positioning data includes sending positioning data that includes the position of the first stage along a second axis that is orthogonal to the first axis.  
     
     
         78 . The method of  claim 77  wherein the step of generating positioning data includes sending positioning data that includes the position of the first stage about a third axis that is orthogonal to the first and second axes.  
     
     
         79 . The method of  claim 75  wherein the step of generating positioning data includes sending positioning data that includes the position of the first stage about a first axis.  
     
     
         80 . The method of  claim 75  wherein the step of moving the first stage includes the first stage having an intended position at a time t1 during the first iteration and an actual position at time t1 1 , wherein the difference between the intended position and the actual position at time t1 is a t1 following error, and wherein the positioning data includes the t1 1  following error.  
     
     
         81 . The method of  claim 80  wherein the step of moving the first stage includes the first stage having an intended position at a time t2 1  during the first iteration and an actual position at time t2 1 , wherein the difference between the intended position and the actual position at time t2 1  is a t2 1  following error, and wherein positioning data includes the t2 1  following error.  
     
     
         82 . The method of  claim 75  further comprising the step of processing the positioning data with a noise filter to remove high frequency noise.  
     
     
         83 . The method of  claim 75  further comprising the step of updating the positioning data using an adaptive algorithm.  
     
     
         84 . The method of  claim 83  wherein the step of updating the positioning data is selectively paused by the control system.  
     
     
         85 . The method of  claim 75  further comprising the step of generating positioning data using a sensor that senses movement of a portion of the precision assembly other than the stage assembly.  
     
     
         86 . The method of  claim 75  further comprising the steps of moving a second stage with a second mover assembly synchronously with the first stage, generating positioning data from movement of the second stage that is sent to the control system, and controlling the first mover assembly with the control system based on the positioning data from movement of the stages to adjust movement of the first stage to improve synchronization of movement of the stages.  
     
     
         87 . The method of  claim 85  wherein the first stage is a reticle stage that retains a reticle and the second stage is a wafer stage that retains a wafer.  
     
     
         88 . A method for manufacturing a device that includes the method of  claim 75 .  
     
     
         89 . A method for manufacturing a wafer on which an image has been formed that includes the method of  claim 75 .  
     
     
         90 . A method for positioning one or more stages of a precision assembly, the method comprising the steps of: 
 moving the first stage with a first mover assembly;    moving a second stage with a second mover assembly synchronously with the first stage;    generating second stage positioning data that includes the position of the second stage; and    controlling movement of the first mover assembly with a control system based on the second stage positioning data to improve the synchronization of movement of the stages.    
     
     
         91 . The method of  claim 90  further comprising the steps of generating first stage positioning data that includes the position of the first stage, and controlling movement of the second mover assembly with the control system based on the first stage positioning data to improve the synchronization of movement of the stages.  
     
     
         92 . The method of  claim 90  wherein the step of generating positioning data includes sending the positioning data to a memory buffer that stores the positioning data.  
     
     
         93 . The method of  claim 90  wherein the step of moving the first stage includes moving the first stage during a first iteration and a subsequent second iteration with the first mover assembly, the second iteration having a similar movement to the first iteration, and generating positioning data from the first iteration that is sent to the control system, and wherein the step of controlling movement of the first mover assembly includes controlling the first mover assembly with the control system to adjust movement of the first stage during the second iteration based on at least a portion of the positioning data from the first iteration of the first stage.  
     
     
         94 . The method of  claim 94  wherein the step of moving the first stage includes the first stage having an intended position at a time t1 1  during the first iteration and an actual position at time t1 1 , wherein the difference between the intended position and the actual position at time t1 1  is a t1 1  following error, and wherein the positioning data of the first stage includes the t1 1  following error.  
     
     
         95 . The method of  claim 94  wherein the step of moving the first stage includes the first stage having an intended position at a time t2 1  during the first iteration and an actual position at time t2 1 , wherein the difference between the intended position and the actual position at time t2 1  is a t2 1  following error, and wherein positioning data of the first stage includes the t2 1  following error.  
     
     
         96 . The method of  claim 90  further comprising the step of generating positioning data using a sensor that senses movement of a portion of the precision assembly other than the stage assembly.  
     
     
         97 . The method of  claim 90  wherein the first stage is a reticle stage that retains a reticle and the second stage is a wafer stage that retains a wafer.  
     
     
         98 . A method for manufacturing a device that includes the method of  claim 90 .  
     
     
         99 . A method for manufacturing a wafer on which an image has been formed that includes the method of  claim 90 .  
     
     
         100 . A method for positioning one or more stages of a stage assembly of an precision assembly, the method comprising the steps of: 
 moving a first stage with a first mover assembly;    monitoring movement of a portion of the precision assembly other than the stage assembly with a sensor;    generating positioning data with the sensor, the positioning data including the position of the portion of the precision assembly being monitored by the sensor; and    controlling movement of the first mover assembly with a control system to adjust movement of the first stage based on at least a portion of the positioning data.    
     
     
         101 . The method of  claim 100  wherein the step of generating positioning data includes generating positioning data of the position of at least a portion of an optical assembly of the precision assembly.  
     
     
         102 . The method of  claim 100  wherein the step of generating positioning data includes generating positioning data of the position of at least a portion of an apparatus frame of the precision assembly.  
     
     
         103 . The method of  claim 100  further comprising the steps of moving a second stage with a second mover assembly synchronously with the first stage, and generating positioning data that includes the position of the second stage, and wherein the step of controlling movement includes controlling movement of the first mover assembly to adjust movement of the first stage based on the second stage positioning data to improve synchronization of movement of the stages.  
     
     
         104 . The method of  claim 103  wherein the first stage is a reticle stage that retains a reticle, and wherein the second stage is a wafer stage that retains a wafer.  
     
     
         105 . The method of  claim 100  wherein the step of moving the first stage includes moving the first stage during a first iteration and a subsequent second iteration having a similar movement to the first iteration, and generating first stage positioning data from movement of the first stage during the first iteration, and wherein step of controlling movement of the first mover assembly includes controlling movement of the first mover assembly during the second iteration based on at least a portion of the positioning data that is generated from the first iteration of the first stage.  
     
     
         106 . The method of  claim 105  wherein the positioning data that is generated from the first iteration of the first stage includes a following error equal to the difference between an intended position and an actual position of the first stage.  
     
     
         107 . The method of  claim 105  wherein the positioning data that is generated from the first iteration of the first stage includes at least a portion of an actual trajectory of the first stage during the first iteration.  
     
     
         108 . The method of  claim 100  further comprising the step of processing the positioning data with a noise filter to remove high frequency noise.  
     
     
         109 . The method of  claim 100  further comprising the step of updating the positioning data using an adaptive algorithm.  
     
     
         110 . The method of  claim 109  wherein the step of updating the positioning data is selectively paused by the control system.  
     
     
         111 . A method for manufacturing a device that includes the method of  claim 100 .  
     
     
         112 . A method for manufacturing a wafer on which an image has been formed that includes the method of  claim 100 .  
     
     
         113 . A first stage assembly comprising: 
 a first stage having a first intended trajectory and a second intended trajectory that is similar to the first intended trajectory;    a first mover assembly that moves the first stage along a first actual trajectory that emulates the first intended trajectory and a subsequent, second actual trajectory that emulates the second intended trajectory, positioning data being generated during the first actual trajectory; and    a control system that receives the positioning data, the control system controlling the first mover assembly to adjust the second actual trajectory of the first stage based on at least a portion of the positioning data.    
     
     
         114 . The stage assembly of  claim 113  wherein the first intended trajectory includes a first starting point and the second intended trajectory includes a second starting point, and wherein the first starting point is the same as the second starting point.  
     
     
         115 . The stage assembly of  claim 114  wherein the first intended trajectory includes a first intended motion and the second intended trajectory includes a second intended motion, and wherein the first intended motion is similar to the second intended motion.  
     
     
         116 . The stage assembly of  claim 113  wherein the first intended trajectory includes a first intended motion and the second intended trajectory includes a second intended motion, and wherein the first intended motion is the same as the second intended motion.  
     
     
         117 . The stage assembly of  claim 116  wherein the first intended trajectory includes a first starting point and the second intended trajectory includes a second starting point, and wherein the first starting point is similar to the second starting point.  
     
     
         118 . The stage assembly of  claim 116  wherein the first intended trajectory includes a first starting point and the second intended trajectory includes a second starting point, and wherein the first starting point is the same as the second starting point.  
     
     
         119 . A stage assembly comprising: 
 a first stage having (i) a first intended trajectory that includes a first point and a first movement, and (ii) a second intended trajectory that includes a second point and a second movement, the second point being the same as the first point, the second movement being similar to the first movement;    a first mover assembly that moves the first stage along a first actual trajectory that emulates the first intended trajectory, and a second actual trajectory that emulates the second intended trajectory, positioning data being generated during the first actual trajectory; and    a control system that receives the positioning data, the control system controlling the first mover assembly to adjust the second actual trajectory of the first stage based on at least a portion of the positioning data.    
     
     
         120 . The stage assembly of  claim 119  wherein the first movement is the same as the second movement.  
     
     
         121 . A stage assembly comprising: 
 a first stage having (i) a first intended trajectory that includes a first point and a first movement, and (ii) a second intended trajectory that includes a second point and a second movement, the second point being similar to the first point, the second movement being the same as the first movement;    a first mover assembly that moves the first stage along a first actual trajectory that emulates the first intended trajectory, and a second actual trajectory that emulates the second intended trajectory, positioning data being generated during the first actual trajectory; and    a control system that receives the positioning data, the control system controlling the first mover assembly to adjust the second actual trajectory of the first stage based on at least a portion of the positioning data.    
     
     
         122 . A method for positioning a first stage of a stage assembly of a precision assembly, the method comprising the steps of: 
 providing a first stage having a first intended trajectory and a second intended trajectory that is similar to the first intended trajectory;    moving the first stage with a first mover assembly along a first actual trajectory that emulates the first intended trajectory and a subsequent, second actual trajectory that emulates the second intended trajectory;    generating positioning data from the first actual trajectory that is sent to a control system; and    controlling the first mover assembly with the control system to adjust the second actual trajectory of the first stage based on at least a portion of the positioning data.    
     
     
         123 . The method of  claim 122  wherein the step of providing a first stage includes the first intended trajectory having a first starting point that is the same as a second starting point of the second intended trajectory.  
     
     
         124 . The method of  claim 123  wherein the step of providing a first stage includes the first intended trajectory having a first intended motion that is similar to a second intended motion of the second intended trajectory.  
     
     
         125 . The method of  claim 122  wherein the step of providing a first stage includes the first intended trajectory having a first intended motion that is the same as a second intended motion of the second intended trajectory.  
     
     
         126 . The method of  claim 125  wherein the step of providing a first stage includes the first intended trajectory having a first starting point that is similar to a second starting point of the second intended trajectory.  
     
     
         127 . The method of  claim 125  wherein the step of providing a first stage includes the first intended trajectory having a first starting point that is the same as a second starting point of the second intended trajectory.