Abstract: An extreme ultraviolet (EUV) mask includes a multilayer Mo/Si stack comprising alternating Mo and Si layers disposed over a first major surface of a mask substrate, a capping layer made of ruthenium (Ru) disposed over the multilayer Mo/Si stack, and an absorber layer on the capping layer. The EUV mask includes a circuit pattern area and a particle attractive area, and the capping layer is exposed at bottoms of patterns in the particle attractive area.

Abstract: An improved key holder includes a seat with curved edges and three corners, a plurality of key-rings, and a push button at the center of the seat. The key-rings have notches and indentations. The push button has insert plates that may engage the notches of the key-rings. A reset spring is disposed below the push button. Chambers accommodating balls and springs are disposed in the corners of the seat for positioning the indentations of the key-rings. The key-rings may hold more keys and allow easy insertion or removal of keys. Besides, the key holder may be attached to the user's clothing or accessories.