PHASE SHIFT MASK BLANK AND PHASE SHIFT MASK

摘要

Disclosed is a photomask blank which is used for producing a photomask to which an ArF excimer laser light is applied.  The photomask blank is characterized by having a light-blocking film (1, 2, 3) on a light-transmitting substrate (10).  The photomask blank is also characterized in that the light-blocking film has a multilayer structure wherein a lower layer (3), an intermediate layer (2) and an upper layer (1) are sequentially arranged in this order from the light-transmitting substrate side; the light-blocking film as a whole has a thickness of not more than 60 nm; the lower layer is composed of a film containing a metal and has a first etching rate; the upper layer is composed of a film containing a metal and has a third etching rate; the intermediate layer is composed of a film containing the same metal as the one contained in the lower layer or the upper layer and has a second etching rate lower than the first etching rate and the third etching rate; and the film thickness of the intermediate layer is not more than 30% of the film thickness of the light-blocking film as a whole.