Abstract:
The invention provides a level sensor configured to determine a height level of a surface of a substrate, comprising a detection unit arranged to receive a measurement beam after reflection on the substrate, wherein the detection unit comprises an array of detection elements, wherein each detection element is arranged to receive a part of the measurement beam reflected on a measurement subarea of the measurement area, and is configured to provide a measurement signal based on the part of the measurement beam received by the respective detection element, and wherein the processing unit is configured to calculate, in dependence of a selected resolution at the measurement subarea, a height level of the measurement subarea, or to calculate a height level of a combination of multiple measurement subareas.
Abstract:
An apparatus, such as a lithographic apparatus, has a metrology frame that has a reference frame mounted thereon that includes a reference surface. A gas gauge is movable relative to the reference frame, metrology frame, and a measured surface. A reference nozzle in the gas gauge provides gas to the reference surface and a measurement nozzle provides gas to the measured surface. A microelectromechanical (MEM) sensor may be used with the gas gauge to sense a difference in backpressure from each of the reference nozzle and the measurement nozzle. Optionally, multiple gas gauges are positioned in an array, which may extend in a direction that is substantially parallel to a plane of the measured surface. The gauges may be fluidly connected to a reference nozzle of the gas gauge. A channel may distribute gas across the array.
Abstract:
The invention provides an object holder to hold an object, comprising: a clamp side to clamp the object, wherein the clamp side is electrically conductive, at least one electrode arranged at a distance from the clamp side, and electrically isolated from the clamp side, a controller arranged to provide an electrode voltage to the at least one electrode based on a measured charge signal representative for a charge level of the object holder and/or the object in order to decrease a potential difference between an electrical potential of the clamp side and an electrical potential of the object.
Abstract:
A topography measurement system includes a radiation source; a first grating; imaging optics; a movement mechanism; detection optics; a second grating; and a detector. The radiation source is configured to generate a radiation beam and includes a light emitting diode to produce to the radiation. The first grating is configured to pattern the radiation beam. The imaging optics is configured to form a first image of the first grating at a target location on a substrate. The movement mechanism is operable to move the substrate relative to the image of the first grating such that the target location moves relative to the substrate. The detection optics is configured to receive radiation from the target location of the substrate and form an image of the first image at the second grating. The detector is configured to receive radiation transmitted through the second grating and produce an output signal.