Abstract: A mask assembly suitable for use in a lithographic process, the mask assembly comprising a patterning device; and a pellicle frame configured to support a pellicle and mounted on the patterning device with a mount; wherein the mount is configured to suspend the pellicle frame relative to the patterning device such that there is a gap between the pellicle frame and the patterning device; and wherein the mount provides a releasably engageable attachment between the patterning device and the pellicle frame.

Abstract: A mask assembly suitable for use in a lithographic process, the mask assembly comprising a patterning device; and a pellicle frame configured to support a pellicle and mounted on the patterning device with a mount; wherein the mount is configured to suspend the pellicle frame relative to the patterning device such that there is a gap between the pellicle frame and the patterning device; and wherein the mount provides a releasably engageable attachment between the patterning device and the pellicle frame.

Abstract: A mask assembly suitable for use in a lithographic process, the mask assembly comprising a patterning device; and a pellicle frame configured to support a pellicle and mounted on the patterning device with a mount; wherein the mount is configured to suspend the pellicle frame relative to the patterning device such that there is a gap between the pellicle frame and the patterning device; and wherein the mount provides a releasably engageable attachment between the patterning device and the pellicle frame.

Abstract: A mask assembly suitable for use in a lithographic process, the mask assembly comprising a patterning device; and a pellicle frame configured to support a pellicle and mounted on the patterning device with a mount; wherein the mount is configured to suspend the pellicle frame relative to the patterning device such that there is a gap between the pellicle frame and the patterning device; and wherein the mount provides a releasably engageable attachment between the patterning device and the pellicle frame.

Abstract: A fluid proximity sensor for surface measurements having a measurement chamber (210) with a measurement nozzle (205), a reference chamber (220) with a reference nozzle (225), and a diaphragm (215) forming an interface between the reference chamber and the measurement chamber. A shroud (280) that encloses the measurement nozzle and reference nozzle provides a peripheral gap (295) between the shroud and a work surface (290) being measured. By connecting either a partial vacuum supply or a partial fluid supply to the shroud, the internal shroud pressure can be raised or lowered and thus the gain-frequency operating regime of the proximity sensor optimized. Movement of the diaphragm in response to differential pressure changes can be sensed by optical, capacitive or inductive means (275).

Abstract: A fluid proximity sensor having one or more measurement nozzles and a reference nozzle coupled to a common chamber. Diaphragms coupled to the measurement nozzles can be sensed by optical, capacitive or inductive means so as to detect changes in pressure. In addition, the number of pressure detectors can be minimized through the use of control valves to selectively couple the nozzles to the detectors, while maintaining the required high level of topographic sensitivity. Further, the measurement nozzle dimensions can be adjusted to optimize proximity measurements in response to accuracy, speed and similar requirements.

Abstract: A fluid proximity sensor for surface measurements having a measurement chamber (210) with a measurement nozzle (205), a reference chamber (220) with a reference nozzle (225), and a diaphragm (215) forming an interface between the reference chamber and the measurement chamber. A shroud (280) that encloses the measurement nozzle and reference nozzle provides a peripheral gap (295) between the shroud and a work surface (290) being measured. By connecting either a partial vacuum supply or a partial fluid supply to the shroud, the internal shroud pressure can be raised or lowered and thus the gain-frequency operating regime of the proximity sensor optimized Movement of the diaphragm in response to differential pressure changes can be sensed by optical, capacitive or inductive means (275).

Abstract: A gas gauge proximity sensor supplying gas in a reverse flow direction from the injection chamber to the measurement chamber. Supplying gas in a reverse flow direction enables the transient behavior in the sensor to more rapidly stabilize, with a resulting increase in bandwidth. Optionally, a scavenger chamber can be used to remove the excess gas by locating a scavenger aperture of the scavenger chamber in close proximity to the exit aperture of the injection chamber. A bridge proximity sensor can be used with a reference chamber to receive gas flow from a location close to the exit aperture of the injection chamber in order to reduce common mode errors.

Abstract: Disclosed are systems, methods, and computer program products for parallel process focus compensation. Such methods may include three steps. First, a first sensor senses a top surface of a wafer to provide first-sensor data which defines a first topographic map of the first surface of the wafer. The first sensor may be, for example, an air gauge. Second, a second sensor senses the top surface of the wafer in parallel with the first sensor to provide second-sensor data which defines a second topographic map of the first surface of the wafer. The second sensor may be, for example, an optical sensor or a capacitance sensor. Third, a calibration module calibrates focus-positioning parameters of an exposure system based on the first- and second-sensor data. The calibration module may be embodied in hardware, software, firmware, or a combination thereof.

Abstract: A gas gauge proximity sensor supplying gas in a reverse flow direction from the injection chamber to the measurement chamber. Supplying gas in a reverse flow direction enables the transient behavior in the sensor to more rapidly stabilize, with a resulting increase in bandwidth. Optionally, a scavenger chamber can be used to remove the excess gas by locating a scavenger aperture of the scavenger chamber in close proximity to the exit aperture of the injection chamber. A bridge proximity sensor can be used with a reference chamber to receive gas flow from a location close to the exit aperture of the injection chamber in order to reduce common mode errors.

Abstract: A fluid assisted gas gauge coupled to a pressure sensor enables proximity measurements to be made with a high bandwidth. A two-chamber gas gauge, containing a gas-filled measurement chamber and a fluid-filled transfer chamber and a diaphragm separating the two chambers, exhausts gas onto the surface being measured, while the incompressible fluid transmits the pressure to a pressure sensor. By minimizing the gas volume of the gas gauge, the response time is enhanced. In addition, the incompressible fluid permits the pressure sensor to be remotely located from the point of measurement without sacrificing the response time performance. In an embodiment, a differential bridge version of the fluid assisted gas gauge reduces common mode effects.

Abstract: A fluid proximity sensor having one or more measurement nozzles and a reference nozzle coupled to a common chamber. Diaphragms coupled to the measurement nozzles can be sensed by optical, capacitive or inductive means so as to detect changes in pressure. In addition, the number of pressure detectors can be minimized through the use of control valves to selectively couple the nozzles to the detectors, while maintaining the required high level of topographic sensitivity. Further, the measurement nozzle dimensions can be adjusted to optimize proximity measurements in response to accuracy, speed and similar requirements.

Abstract: Disclosed are systems, methods, and computer program products for parallel process focus compensation. Such methods may include three steps. First, a first sensor senses a top surface of a wafer to provide first-sensor data which defines a first topographic map of the first surface of the wafer. The first sensor may be, for example, an air gauge. Second, a second sensor senses the top surface of the wafer in parallel with the first sensor to provide second-sensor data which defines a second topographic map of the first surface of the wafer. The second sensor may be, for example, an optical sensor or a capacitance sensor. Third, a calibration module calibrates focus-positioning parameters of an exposure system based on the first- and second-sensor data. The calibration module may be embodied in hardware, software, firmware, or a combination thereof.

Abstract: A choked-flow orifice gas gauge proximity sensor for sensing a difference between a reference surface standoff and a measurement surface standoff is disclosed. Unlike existing proximity sensors, the gas gauge proximity sensor of the present invention replaces the use of a mass flow controller with a choked flow orifice. The use of a choked flow orifice provides for reduced equipment cost and improved system reliability. A gas supply forces gas into the proximity sensor. The gas is forced through the choked flow orifice to achieve sonic conditions at which time the mass flow rate becomes largely independent of pressure variations. The flow of gas proceeds from the choked flow orifice into a sensor channel system. A mass flow sensor within the sensor channel system monitors flow rates to detect measurement standoffs that can be used to initiate a control action.

Abstract: A vacuum-driven gas gauge proximity sensor for sensing a difference between a reference surface standoff and a measurement surface standoff is disclosed. Unlike existing proximity sensors, the vacuum-driven gas gauge proximity sensor uses a vacuum to reverse the traditional flow of gas through a proximity sensor, such that gas flows inward across measurement and reference standoffs through measurement and reference nozzles. The conditioned ambient gas that is vacuumed into the reference and measurement nozzles flows through reference and measurement channels that are coupled at a junction into a single channel. The single channel is coupled to the vacuum that is used to evacuate the conditioned ambient gas through the proximity sensor. A bridge channel couples the reference and measurement channels. A mass flow sensor along the bridge channel monitors flow rates to detect measurement standoffs that can be used to initiate a control action. A pump-driven liquid flow proximity sensor is also disclosed.

Abstract: A system and method that use a fluid gauge proximity sensor. A source of modulated unidirectional or alternating fluid flow travels along at least one path having a nozzle and a flow or pressure sensor. The fluid exists at a gap between the nozzle and a target. The sensor outputs an amplitude modulated signal that varies according to a size of the gap. The amplitude modulated signal is processed either digitally or in analog devices, which can include being filtered (e.g., band pass, band limited, high pass, etc. filter) to include the modulated frequency and sufficient bandwidth on either side of that frequency and/or being demodulated using a demodulator operating at the acoustical driver modulation frequency. Using this system and method can result in only ambient acoustical energy in a desired frequency range of the device actually having the opportunity to interfere with the device operation. This can lower the devices overall sensitivity to external acoustical noise and sensor offset.

Abstract: A system and method are used to calibrate a focus portion of an exposure section of a lithography tool. A wafer is exposed so that a resulted or formed patterned image is tilted with respect to the wafer. The tilting can be imposed based on controlling a wafer stage to tilt the wafer or a reticle stage to tilt the reticle. The wafer is developed. Characteristics of the tilted patterned image are measured with a portion of the lithography tool to determine focus parameters of an exposure system. The portion can be an alignment system. The measuring step can measure band width and/or band location of the tilted patterned image. Sometimes, more than one patterned image is formed on the wafer, then the measuring step can measure distance between bands and shifting of the bands with respect to a central axis of the wafer. The focus parameters can be focus tilt errors and/or focus offset. The focus parameters are used to perform calibration.

Abstract: A virtual gauging method for use in a lithographic process includes gauging a region at a surface of a wafer when the region is located away from an axis of illumination producing wafer surface data, while other portions of the wafer are being illuminated. The method also includes acquiring time-domain measurements representing the wafer surface data and converting the time-domain measurements into space-domain measurements. This conversion can be done using a finite-impulse-response (FIR) filter. The FIR filter can be triggered with a spatial interrupt, and a width of the FIR filter is modified in response to a velocity of travel of the wafer. The method further includes converting space-domain measurements into wafer correction data.

Abstract: A gas gauge proximity sensor modulates a gas stream that is used to feed reference and measurement air gauges, respectively, in a reference portion proximate a reference surface and a measurement portion proximate a measurement surface. The gas stream can be modulated at a frequency at which there is minimal acoustical interference energy (e.g., minimal noise) in demodulated output signal. The sensor output can be filtered so that a measurement signal includes only the modulated frequency and side bands of that frequency to include the desired response band of the device as a whole. The filtered signal can be demodulated using a demodulator operating at a same frequency as the modulator to produce the demodulated output signal. In this embodiment, substantially only ambient acoustical energy in the band pass region may interfere with the device operation. Alternatively, the modulation can be introduced through the reference portion. A reference nozzle sets up a pressure field with the reference surface.

Abstract: A system and method that use a fluid gauge proximity sensor. A source of modulated unidirectional or alternating fluid flow travels along at least one path having a nozzle and a flow or pressure sensor. The fluid exists at a gap between the nozzle and a target. The sensor outputs an amplitude modulated signal that varies according to a size of the gap. The amplitude modulated signal is processed either digitally or in analog devices, which can include being filtered (e.g., band pass, band limited, high pass, etc. filter) to include the modulated frequency and sufficient bandwidth on either side of that frequency and/or being demodulated using a demodulator operating at the acoustical driver modulation frequency. Using this system and method can result in only ambient acoustical energy in a desired frequency range of the device actually having the opportunity to interfere with the device operation. This can lower the devices overall sensitivity to external acoustical noise and sensor offset.