Nikon Corporation

Kazuo Masaki

Bausan Yuan

Kazuhiro Hirano

Yi-Ping Hsin

Michael B Binnard

Pai-Hsueh Yang

Scott Coakley

Gabor D Szoboszlay

Ryoichi Kawaguchi

Susumu Isago

Xiao-Feng Yang

Christopher B Smith

Methods and apparatus for providing vibration compensation using position measurements are disclosed. According to one aspect of the present invention, a method of compensating for vibrations of an object includes obtaining a plurality of position measurements associated with the object. The method also includes processing the plurality of position measurements to determine a derivative acceleration, and determining a compensatory force to counteract the vibrations of the object. Determining the compensatory force includes using the derivative acceleration. Finally, the method includes applying the compensatory force to the object.

Direct derivative feedforward vibration compensation system

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.

On-machine methods for identifying and compensating force-ripple and side-forces produced by actuators on a multiple-axis stage

Embodiments of the invention relate to a cable force feedforward approach that takes into account the cable force in the counter-mass trajectory computation to reduce or eliminate vibration of the lens body caused by the cable force disturbance and corrective force exerted by the trim motors. In one embodiment, a method provides cable force feedforward control for a counter-mass of a stage with a cable connected to the counter-mass and using the cable force feedforward control to control one or more trim motors to produce a trim motor output force to be applied to the counter-mass, the counter-mass moving in response to a reaction force from movement of the stage. The method comprises measuring a counter-mass position y of the counter-mass in response to forces applied to the counter-mass; measuring a cable force &#x192; exerted on the counter-mass by the cable which is connected to the counter-mass; generating a cable force function {circumflex over (&#x192;)}(y, {dot over (y)}) of the measured cable force &#x192; versus the counter-mass position y; and computing the trim motor output force u as where w is a weighting function having a value from 0 to 1 and is selected for optimization.

Minimum force output control method for counter-mass with cable

A projection exposure apparatus including a projection optical system for projecting a pattern formed in a reticle onto a photosensitive substrate, and an alignment system for positioning the reticle and the photosensitive substrate with respect to each other by observing a reticle mark alignment formed on the reticle and a substrate alignment mark formed on the photosensitive substrate; wherein the alignment system comprises an imaging section having an imaging surface tilted with respect to an optical axis of the alignment system and with respect to a direction orthogonal to a measuring direction for each of the alignment marks, the imaging section having respective best focus positions for the alignment marks at different positions on the imaging surface; and wherein the alignment marks are simultaneously detected at the respective best focus positions so as to position the reticle and the photosensitive substrate with respect to each other. The best focus positions are determined by the focus detecting section within the image processing system according to image signals obtained from the imaging section.

Projection exposure apparatus

Growing community of inventors

Saitama, Japan

Kazuo Masaki