Phase shift photomask, phase shift photomask blank, and process for fabricating them

A phase shift photomask having at least a phase shift pattern on a transparent substrate, characterized in that the peripheral region of the phase shift pattern area on the substrate is removed to confine the phase shift layer within an area smaller than that of the substrate.

A process for fabricating a phase shift photomask blank for projection exposure, characterized by:

• forming a phase shift layer comprising spin-on glass all over the surface of one side of a transparent substrate so that light which impinges on said photomask blank and passes through said phase shift layer is shifted in phase, and
• immersing only the peripheral region of the substrate in an etching solution to etch away the peripheral region of the phase shift layer,
• whereby the phase shift layer is confined within an area smaller than that of the substrate.

A process for fabricating a phase shift photomask, characterized by:

• forming a phase shift pattern all over the surface of one side of a transparent substrate, and
• immersing only the peripheral region of the substrate in an etching solution to etch away the peripheral region of the phase shift pattern,
• whereby the phase shift pattern is confined within an area smaller than that of the substrate.

A process for fabricating a phase shift photomask blank for projection exposure, characterized by including the step of providing a layer of material capable of repelling an overlying phase shift layer comprising spin-on glass on the peripheral region of a transparent substrate, whereby, when the overlying phase shift layer is provided so that light which impinges on said photomask blank and passes through said phase shift layer is shifted in phase, only the peripheral region of the phase shift layer is repelled by said layer of material for removal.

A process for fabricating a phase shift photomask, said process comprising the steps of:

• providing a layer of material on the peripheral region of a transparent substrate;
• providing a phase shift layer overlying said transparent substrate, wherein the material provided on the peripheral region of the transparent substrate repels formation of a phase shift pattern area so that a phase shift pattern area is not formed on the peripheral region of the transparent substrate.

A process for fabricating a phase shift mask blank for projection exposure, characterized by including the steps of providing a layer of material capable of lifting off an overlying phase shift layer comprising spin-on glass on the peripheral region of a transparent substrate, providing the overlying phase shift layer so that light which impinges on said phase shift mask blank and passes through said phase shift layer is shifted in phase, and lifting off the phase shift layer.

A process for fabricating a phase shift mask, comprising the steps of providing a layer of material capable of lifting off an overlying phase shift pattern area comprising spin-on glass on the peripheral region of a transparent substrate, providing the overlying phase shift pattern area, and lifting off the phase shift pattern area.