Abstract: Control systems are disclosed that control motion of a first movable body along a first trajectory in coordination with motion of a second movable body along a second trajectory. An exemplary system has first and second controllers. The first controller provides first driving commands to the first movable body. The second controller provides second driving commands to the second movable body. A first control loop associated with the first controller includes feedback to the first controller of position-error data regarding the first movable body. A second control loop associated with the second controller includes feedback to the second controller of position-error data regarding the second movable body. A synchronization target filter couples the first and second control loops and causes the first controller to move the first movable body in a manner that tracks the position-error data of the second movable body at one or more frequencies of interest.

Abstract: A method for determining a commutation offset for a mover (250A) of a mover assembly (220C) that moves and positions a stage (220A) relative to a stage base (220B) includes controlling the mover assembly (220C) in a closed loop fashion to maintain the position of the stage (220A) along a first axis and along a second axis with the stage (220A) levitated above the stage base (220B). The method also includes the steps of (i) directing current to a coil array (240) of the mover assembly (220C) so that the mover assembly (220C) imparts a disturbance on the stage (220A); and (ii) evaluating one or more forces generated by the mover assembly (220C) as a result of the disturbance on the stage (220A) created by the mover (250A). Further, a method for generating a compensation map (1402) includes sequentially directing a plurality of excitation signals to the control of the mover assembly (220C) and determining the control commands that result from the plurality of excitation signals.

Abstract: A method for determining a commutation offset for a mover (250A) of a mover assembly (220C) that moves and positions a stage (220A) relative to a stage base (220B) includes controlling the mover assembly (220C) in a closed loop fashion to maintain the position of the stage (220A) along a first axis and along a second axis with the stage (220A) levitated above the stage base (220B). The method also includes the steps of (i) directing current to a coil array (240) of the mover assembly (220C) so that the mover assembly (220C) imparts a disturbance on the stage (220A); and (ii) evaluating one or more forces generated by the mover assembly (220C) as a result of the disturbance on the stage (220A) created by the mover (250A). Further, a method for generating a compensation map (1402) includes sequentially directing a plurality of excitation signals to the control of the mover assembly (220C) and determining the control commands that result from the plurality of excitation signals.

Abstract: An exemplary stage assembly has movable stage mass and counter-mass. A stage motor is coupled to the stage mass and counter-mass such that stage-mass motion imparted by the stage motor causes a reactive motion of the counter-mass counter to the motion of the stage mass. At least one trim-motor is coupled to the counter-mass. A control system commands the trim-motor to regulate movement of the counter-mass in reaction to stage-mass motion. A PI feedback controller receives the following-error of the counter-mass and generates corresponding center-of-gravity (CG) force commands and trim-motor force commands to the trim-motor(s) to produce corrective counter-mass motion. A trim-motor force limiter receives trim-motor force commands and produces corresponding limited trim-motor force commands that are fed back as actual CG force commands to the feedback controller to modify integral terms of the feedback controller according to the limited trim-motor force commands.

Abstract: Methods, apparatus, and systems are disclosed for identifying force-ripple and/or side-forces in actuators used for moving a multiple-axis stage. The identified force-ripple and/or side-forces can be mapped, and maps of corresponding position-dependent compensation ratios useful for correcting same are obtained. The methods are especially useful for stages providing motion in at least one degree of freedom using multiple (redundant) actuators. In an exemplary method a stage member is displaced, using at least one selected actuator, multiple times over a set distance in the range of motion of the subject actuator(s). Each displacement has a predetermined trajectory and respective starting point in the range. For each displacement, respective section force-command(s) are extracted and normalized to a reference section force-command to define a section compensation-ratio.

Abstract: Methods are disclosed for calibrating a force constant of a movable stage. In an exemplary method, in first and second preliminary pre-stepping motions of the stage, a baseline force and a calibration force, respectively, as exerted by the stage are measured. From a force-variation ratio of the baseline force and calibration force an inverse closed loop factor is estimated. In at least one subsequent pre-stepping motion of the stage before a respective use of the stage for holding an object, a residual force-variation ratio is estimated, a force-compensation factor is updated from the residual force-variation ratio, and a respective force-variation coefficient is determined from the force-compensation factor.

Abstract: Disclosed are, inter alia, optical components that include an optical element (e.g., mirror) and at least three active-isolation mounts mounting the optical element to a frame (e.g., optical barrel or optical frame). An active-isolation mount has a non-contacting actuator connecting a respective location on the optical element to the frame and provides movability of the respective location relative to the frame in at least one direction. At least one displacement sensor is associated with each respective location on the optical element. The displacement sensors are sensitive to displacements of the respective locations in at least one respective direction and reference the displacements to an absolute reference. The actuators and sensors are connected to a servo control loop to provide feedback control.

Abstract: Embodiments of the invention compensate for one or more effects of a stage motor in a precision stage device. A feedforward module receives an input signal corresponding to the effect of the motor and generates a feedforward control signal that can be used to modify a motor control signal to compensate for the effect of the motor. In some embodiments, a control system is provided to compensate for a back-electromotive force generated by a motor, while in other embodiments, a control system may compensate for an inductive effect of a motor. Embodiments of the invention may be useful in precision stage devices, for example, lithography devices such as steppers and scanners.

Abstract: Stage assemblies and control methods are disclosed. An exemplary stage assembly includes a movable stage and a control system. The stage-control system has first and second control loops. In the first control loop a first controller is programmed with a feedback-control transfer-function that determines a feedback-control output from an input including a following-error of the stage. The second control loop includes an inverse closed loop having an inverse plant model and a second controller programmed with an adaptive transfer-function connected to receive inputs including the following-error and the feedback-control output. The second controller determines, from the inputs, an adapted control output to the stage. The adaptive transfer-function can be, e.g., an AFC transfer-function producing an AFC controlled output or an ILC transfer-function producing an ILC controlled output.

Abstract: Stage assemblies and control methods are disclosed. An exemplary assembly includes a first stage and first and second controllers. The first controller feedback-controls the first stage according to a respective parameter vector. The second controller controls the first stage by feed-forward control, according to a respective parameter vector. The controllers perform iterative feedback tuning IFT, including minimization of a cost-function of the parameter vectors from the first and second controllers. The second controller receives data including first-stage trajectory, and the first controller receives data including first-stage following-error. A suitable application of the assembly is in a microlithography system or other high-precision system.

Abstract: Disclosed are, inter alia, optical components that include an optical element (e.g., mirror) and at least three active-isolation mounts mounting the optical element to a frame (e.g., optical barrel or optical frame). An active-isolation mount has a non-contacting actuator connecting a respective location on the optical element to the frame and provides movability of the respective location relative to the frame in at least one direction. At least one displacement sensor is associated with each respective location on the optical element. The displacement sensors are sensitive to displacements of the respective locations in at least one respective direction and reference the displacements to an absolute reference. The actuators and sensors are connected to a servo control loop to provide feedback control.

Abstract: A stage assembly (220) that moves a work piece (200) about a first axis and along a first axis includes a first stage (238), a second stage (240) that retains the work piece (200), a second mover assembly (244), a measurement system, and an initialization system (1081A). The second mover assembly (244) moves the second stage (240) relative to the first stage (238) about the first axis. The measurement system (22) monitors the position of the second stage (240) about the first axis when the second stage (240) is positioned within a working range about the first axis. The initialization system (1081A) facilitates movement of the second stage (240) about the first axis when the second stage (240) is rotated about the first axis outside the working range. The second mover assembly (244) can include a mover (255) and a dampener (410) that reduces the transmission of vibration from the first stage (238) to the second stage (240).

Abstract: Methods, apparatus, and systems are disclosed for identifying force-ripple and/or side-forces in actuators used for moving a multiple-axis stage. The identified force-ripple and/or side-forces can be mapped, and maps of corresponding position-dependent compensation ratios useful for correcting same are obtained. The methods are especially useful for stages providing motion in at least one degree of freedom using multiple (redundant) actuators. In an exemplary method a stage member is displaced, using at least one selected actuator, multiple times over a set distance in the range of motion of the subject actuator(s). Each displacement has a predetermined trajectory and respective starting point in the range. For each displacement, respective section force-command(s) are extracted and normalized to a reference section force-command to define a section compensation-ratio.

Abstract: A stage assembly (220) that moves a work piece (200) about a first axis and along a first axis includes a first stage (238), a second stage (240) that retains the work piece (200), a second mover assembly (244), a measurement system, and an initialization system (1081A). The second mover assembly (244) moves the second stage (240) relative to the first stage (238) about the first axis. The measurement system (22) monitors the position of the second stage (240) about the first axis when the second stage (240) is positioned within a working range about the first axis. The initialization system (1081A) facilitates movement of the second stage (240) about the first axis when the second stage (240) is rotated about the first axis outside the working range. The second mover assembly (244) can include a mover (255) and a dampener (410) that reduces the transmission of vibration from the first stage (238) to the second stage (240).

Abstract: A stage assembly (220) for moving a device (200) includes a stage (208), and actuator pair (226) and a control system (224). The actuator pair (226) includes a first actuator (228) that is coupled to the stage (208). The first actuator (228) has a first E core (236) and a first I core (240) that is spaced apart a first gap (g1) from the first E core (236). The control system (224) directs current to the first actuator (228) to move the stage (208). In one embodiment, the amount of current directed to the first actuator (228) is determined utilizing a first parameter (a) that is added to the first gap (g1). The value of the first parameter (a) is determined by experimental testing. Additionally, the amount of current directed to the first actuator (228) can be determined utilizing a second parameter (b) that is added to the first gap (g1). The value of the second parameter (b) is determined by experimental testing.

Abstract: A polishing apparatus (10) for polishing a device (12) with a polishing pad (48) includes a pad holder (50) and an actuator assembly (432). The pad holder (50) retains the polishing pad (48). The actuator assembly (432) includes a plurality of spaced apart actuators (438F) (438S) (438T) that are coupled to the pad holder (50). The actuators (438F) (438S) (438T) cooperate to direct forces on the pad holder (50) to alter the pressure of the polishing pad (48) on the device (12). At least one of the actuators (438F) (438S) (438T) includes a first actuator subassembly (440) and a second actuator subassembly (442) that interacts with the first actuator subassembly (440) to direct a force on the pad holder (50). The second actuator subassembly (442) is coupled to the pad holder (50) and the second actuator subassembly (442) rotates with the pad holder (50) relative to the first actuator subassembly (440).

Abstract: Embodiments of the present invention are directed to compensating for force ripple of an apparatus driven by a force produced by a linear motor. In one embodiment, a method of compensating for force ripple comprises generating force commands for a trajectory starting at a plurality of starting positions of the apparatus driven by the linear motor to produce different trajectory motions based on the same trajectory at the plurality of starting positions, the force commands each including peaks of large acceleration/deceleration and valleys of low force levels; calculating an average of the force commands during large acceleration/deceleration generated based on trajectory motions for the plurality of starting positions; calculating a variation ratio of the force command for each trajectory motion to the calculated average of the force commands; and compensating for force ripple in the apparatus based on the calculated variation ratio to control the force applied by the linear motor to the apparatus.

Abstract: A stage assembly (220) that moves a work piece (200) about a first axis and along a first axis includes a first stage (238), a second stage (240) that retains the work piece (200), a second mover assembly (244), a measurement system, and an initialization system (1081A). The second mover assembly (244) moves the second stage (240) relative to the first stage (238) about the first axis. The measurement system (22) monitors the position of the second stage (240) about the first axis when the second stage (240) is positioned within a working range about the first axis. The initialization system (1081A) facilitates movement of the second stage (240) about the first axis when the second stage (240) is rotated about the first axis outside the working range. The second mover assembly (244) can include a mover (255) and a dampener (410) that reduces the transmission of vibration from the first stage (238) to the second stage (240).

Abstract: A stage assembly (220) for moving a device (200) includes a stage (208), an attraction-only type actuator pair (426) that moves the stage (208), and a control system (24). In one embodiment, the actuator pair (426) includes a first electromagnet (436F), a first conductor (438F) and a first target (440F) having a first target surface (442F). The actuator pair also includes a second electromagnet (436S), a second conductor (438S) and a second target (440S) having a second target surface (442S). The first electromagnet (436F) is positioned at a first angle ?1 relative to a first target surface (442F) and the second electromagnet (436S) is positioned at a second angle ?2 relative to the second target surface (442S). The control system (24) directs a first current to one or more of the electromagnets based on at least one of the angles ?1, ?2. Further, one or more electromagnets (436) can include a first measurement point and a second measurement point.

Abstract: A polishing apparatus (10) for polishing a device (12) with a polishing pad (48) includes a pad holder (50) and an actuator assembly (432). The pad holder (50) retains the polishing pad (48). The actuator assembly (432) includes a plurality of spaced apart actuators (438F) (438S) (438T) that are coupled to the pad holder (50). The actuators (438F) (438S) (438T) cooperate to direct forces on the pad holder (50) to alter the pressure of the polishing pad (48) on the device (12). At least one of the actuators (438F) (438S) (438T) includes a first actuator subassembly (440) and a second actuator subassembly (442) that interacts with the first actuator subassembly (440) to direct a force on the pad holder (50). The second actuator subassembly (442) is coupled to the pad holder (50) and the second actuator subassembly (442) rotates with the pad holder (50) relative to the first actuator subassembly (440).