X-ray mask blank and method of manufacturing the same

An X-ray mask blank comprising a substrate, an X-ray transparent film on said substrate, and an X-ray absorber film, said X-ray absorber film having a predetermined area in which a stress distribution pattern is formed, said pattern being defined by the existence of a stress between 0 and .+-.10 MPa at a plurality of points at which stresses are measured on the predetermined area, wherein said X-ray absorber film has a thickness between 0.1 and 1.0 .mu.m, and wherein said X-ray absorber film is specified by a product of said stress and said thickness both of which are measured at the same points, both maximum and minimum values of said product falling within a range between 0 and .+-.5.times.10.sup.3 dyn/cm.

A method of producing an X-ray mask blank comprising a step of forming an X-ray absorber film on an X-ray transparent film, said X-ray transparent film, said X-ray transparent film being formed on a substrate, said step comprising sub-steps of:

• flattening a surface of said X-ray transparent film to have a smooth surface within a range not more than 2.0 nmRa;
• and
• forming said X-ray absorber film on said smooth surface, wherein said forming step comprises controlling a stress distribution of said X-ray absorber film on a predetermined area thereof so that a pattern of stress distribution is formed which exhibits for respective portions of the pattern a stress of 0 to .+-.10 MPa at a plurality of points at which stresses are measured on the predetermined area.

A method of producing an X-ray mask blank comprising a step of forming an X-ray absorber film on an X-ray transparent film, said X-ray transparent film being formed on a substrate, wherein said absorber film forming step comprises the sub-steps of forming said absorber film (1) to have a thickness between 0.1 and 1.0 .mu.m and a predetermined area in which is formed a stress distribution pattern that is defined by values of stress between a maximum and a minimum value, and (2) to exhibit a stress of 0 to .+-.10 MPa at a plurality of points on the predetermined area and (3) to obtain a product of said thickness and said stress based on a control of said thickness, said stress and stress distribution in said step, wherein both of said thickness and said stress are measured at the same points on said predetermined area, both maximum and minimum values of said product falling within a range between 0 to .+-.5.times.10.sup.3 dyn/cm.