Systems and methods that include providing for measuring a first topographical height of a substrate at a first coordinate on the substrate and measuring a second topographical height of the substrate at a second coordinate on the substrate are provided. The measured first and second topographical heights may be provided as a wafer map. An exposure process is then performed on the substrate using the wafer map. The exposure process can include using a first focal point when exposing the first coordinate on the substrate and using a second focal plane when exposing the second coordinate on the substrate. The first focal point is determined using the first topographical height and the second focal point is determined using the second topographical height.

A gas gauge proximity sensor comprising a measurement gas flow channel having an optical pressure sensor for comparing a pressure of the first gas flow and a reference pressure; the optical pressure sensor comprising a first optical cavity fluidly connected to the measurement channel and a second optical cavity fluidly connected to the reference pressure, with the optical cavities being configured to receive electromagnetic radiation and output reflected electromagnetic radiation, the optical pressure sensor further being configured to combine the reflected electromagnetic radiation from the first optical cavity with the reflected electromagnetic radiation from the second optical cavity and determine, based on the combined electromagnetic radiation, a pressure difference between the pressure of the first gas flow and the reference pressure and determine, based on the pressure difference, a distance between the measurement outlet and the measurement object.

A height measurement apparatus comprising an array of differential pressure sensors, each differential pressure sensor comprising a reference outlet and a measurement outlet, the reference outlet being a predetermined distance from a reference surface, and each differential pressure sensor further comprising an inlet configured to provide pressurized gas for the reference outlet and the measurement outlet. A flexible membrane is positioned such that a reference side of the flexible membrane is in fluid communication with the reference outlet and a measurement side of the flexible membrane is in fluid communication with the measurement outlet. The flexible membrane is configured to move when a pressure change occurs at the measurement outlet and a detector is configured to monitor the movement of the flexible membrane.

A lithographic apparatus uses a height sensor to obtain height sensor data representing a topographical variation across a substrate. The height sensor data is used to control focusing of a device pattern at multiple locations across the substrate. A controller identifies one or more first areas where height sensor data is judged to be reliable and one or more second areas where the height sensor data is judged to be less reliable. Substitute height data is calculated for the second areas using height sensor data for the first areas together with prior knowledge of expected device-specific topography. The focusing of the lithographic apparatus is controlled using a combination of the height data from the sensor and the substitute height data.

Embodiments of the present disclosure generally relate to systems and methods for performing photolithography processes. In one embodiment, laminar gas flow is provided inside a photolithography system during operation. With laminar gas flow instead of turbulent gas flow inside the system, accuracy of the measurement of the location of a substrate disposed inside the system is improved due to the improved signal integrity of interferometers.

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.

Embodiments of the present disclosure generally relate to systems and methods for performing photolithography processes. In one embodiment, laminar gas flow is provided inside a photolithography system during operation. With laminar gas flow instead of turbulent gas flow inside the system, accuracy of the measurement of the location of a substrate disposed inside the system is improved due to the improved signal integrity of interferometers.