Patent ID: 8709685
Filing Date: 2014-04-29
Classification: B82Y,G03F

Abstract:
1. A reflective mask blank for use in EUV lithography using EUV light as exposure light, comprising a substrate, a multilayer reflective film formed over said substrate and adapted to reflect the exposure light, and an absorber film formed over said multilayer reflective film and adapted to absorb the exposure light, wherein said absorber film is made of a material containing tantalum (Ta) and has a film density of 6.0 to 16.0 g/cm said absorber film has a laminated structure comprising an uppermost layer and a lower layer other than said uppermost layer, said uppermost layer is made of a material containing tantalum (Ta) and oxygen (O), said lower layer is made of a material containing tantalum (Ta) and nitrogen (N), and said uppermost layer has a film density smaller than that of said lower layer.