摘要:
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.
摘要:
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.
摘要:
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). In addition, the stage assembly (220) can include a control system (24) that directs power to the mover (255) to position the second stage (240) and to compensate for vibration of the first stage (238).
摘要:
According to one aspect of the present invention, a stage apparatus includes a first stage, a first magnet arrangement, and a stator arrangement that includes a first coil having a first width. The first magnet arrangement is associated with the first stage, and includes a first quadrant and a second quadrant or, more generally, a first sub-array and a second sub-array. The first quadrant has at least one first magnet arranged parallel to a first axis, and the second quadrant has at least one second magnet arranged parallel to a second axis. The first quadrant is adjacent to the second quadrant relative to the first axis, and is spaced apart from the second quadrant by a distance relative to the second axis. The stator arrangement is configured to cooperate with the first magnet arrangement to drive the first stage
摘要:
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.
摘要:
An actuator assembly (432) for positioning a pad (48) includes a first actuator assembly (440), a second actuator subassembly (442) and a control system (524). In one embodiment, the first actuator subassembly (440) includes a first core (502), and a conductor (504) secured to the first core (502), and the second actuator subassembly (442) includes a second core (506) spaced apart a component gap (444) from the first core (502). Further, the control system (524) directs current to the conductor (504) to attract the second core (506) to the first core (502). In one embodiment, the amount of current directed to the conductor (504) is calculated without measuring the component gap (444).
摘要:
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. Multiple section compensation-ratios are assembled, as functions of displacement in the range, to provide a map of compensation ratios for the actuator(s) throughout the range.
摘要:
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.
摘要:
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.
摘要:
According to one aspect, a method for controlling a stage that is a part of a stage apparatus and is coupled to a voice coil motor (VCM) and an EI-core actuator arrangement includes driving the stage, identifying a frequency associated with the stage, and determining whether the frequency is below a frequency setpoint. The method also includes providing a first control force on the stage using the EI-core actuator arrangement when it is determined that the frequency is below the frequency setpoint, and providing the first control force on the stage using the VCM when it is determined that the frequency is not below the frequency setpoint.