Abstract: Measurement cavities described herein include a cylindrical chamber having a first open end and a second open end; a first cap covering the first open end of the cylindrical chamber and a second cap covering the second open end of the cylindrical chamber, wherein the first and second caps hermetically seal the cylindrical chamber and wherein the first cap is rigidly coupled to the second cap; and a wafer holder positioned within and coupled to the cylindrical chamber. The measurement cavity has a mass m, a stiffness k, and a damping constant c configured such that the transmissibility ? x F ? of an input force at 60 Hz in the measurement cavity is reduced by a factor of at least 10 and the measurement cavity has a natural frequency of greater than 300 Hz.

Abstract: Measurement cavities described herein include a cylindrical chamber having a first open end and a second open end; a first cap covering the first open end of the cylindrical chamber and a second cap covering the second open end of the cylindrical chamber, wherein the first and second caps hermetically seal the cylindrical chamber and wherein the first cap is rigidly coupled to the second cap; and a wafer holder positioned within and coupled to the cylindrical chamber. The measurement cavity has a mass m, a stiffness k, and a damping constant c configured such that the transmissibility ? x F ? of an input force at 60 Hz in the measurement cavity is reduced by a factor of at least 10 and the measurement cavity has a natural frequency of greater than 300 Hz.

Abstract: Systems and methods for reducing laser coherence effect within an optical system are disclosed. A system includes an acoustic device, a signal generator electrically coupled to the acoustic device, where the signal generator generates an electrical signal comprising a predefined frequency and a predefined amplitude for output by the acoustic device, and an optical system comprising a laser light source configured to produce a beam where one or more optical elements are disposed along the beam path that impinges or propagates through the one or more optical elements. The acoustic device is positioned at a distance from the one or more optical elements such that an acoustic signal emitted by the acoustic device causes one or more optical elements to vibrate such that laser coherence effects of the beam are reduced.

Abstract: An optical mount includes a support substrate defining an aperture configured to receive an optical element. A support assembly is positioned proximate a perimeter of the aperture. The support assembly includes a resilient member configured reflects in response to relative motion between the optical element and the support substrate. A support plate is positioned on the resilient member and is in contact with the optical element.

Abstract: The methods disclosed herein include recording at near-vertical first and second measurement positions respective first and second interferograms of the photomask surface and defining a difference map as the difference between the first and second interferograms. Respective first and second normal forces on the photomask are also measured at the first and second measurement positions. The change in the normal force is used define a scaling factor, which is applied to the difference map to define a scaled difference map. A compensated flatness measurement with a reduced shape contribution due to gravity is obtained by subtracting the scaled difference map from the first interferogram. An interferometer-based flatness measurement system is also disclosed.

Abstract: The methods disclosed herein include recording at near-vertical first and second measurement positions respective first and second interferograms of the photomask surface and defining a difference map as the difference between the first and second interferograms. Respective first and second normal forces on the photomask are also measured at the first and second measurement positions. The change in the normal force is used define a scaling factor, which is applied to the difference map to define a scaled difference map. A compensated flatness measurement with a reduced shape contribution due to gravity is obtained by subtracting the scaled difference map from the first interferogram. An interferometer-based flatness measurement system is also disclosed.