Abstract: An extreme ultraviolet mask including a substrate, a reflective multilayer stack on the substrate and patterned absorber layer on the reflective multilayer stack is provided with a pellicle membrane frame attached to the substrate. In some embodiments, the pellicle membrane frame is attached to the substrate using an adhesive between the pellicle membrane frame and the substrate. In some embodiments, the pellicle membrane frame is located in a trench formed in the reflective multilayer stack and patterned absorber layer. In other embodiments, the pellicle membrane frame not located in a trench formed in the reflective multilayer stack and patterned absorber layer.

Abstract: In pellicle cleaning, a gas is flowed on a pellicle using at least one gas nozzle. During the flowing, the pellicle is moved respective to the at least one gas nozzle. During the flowing, the pellicle is exposed to ionized gas generated by at least one alpha ionizer. Also during the flowing, an ultrasonic wave is applied to the pellicle using an ultrasound transducer or transducer array. The gas nozzle may have a nozzle aperture comprising a slit or a linear array of apertures arranged parallel with a pellicle membrane of the pellicle.

Abstract: In pellicle cleaning, a gas is flowed on a pellicle using at least one gas nozzle. During the flowing, the pellicle is moved respective to the at least one gas nozzle. During the flowing, the pellicle is exposed to ionized gas generated by at least one alpha ionizer. Also during the flowing, an ultrasonic wave is applied to the pellicle using an ultrasound transducer or transducer array. The gas nozzle may have a nozzle aperture comprising a slit or a linear array of apertures arranged parallel with a pellicle membrane of the pellicle.