Projectin exposure apparatus

A projection exposure apparatus for transferring a pattern formed on a mask onto a wafer, comprising:

• a light source for generating light illuminating said mask,
• a first focusing optical system for focusing the light from said light source,
• a uniforming optical system for uniforming the light focused by said first focusing optical system,
• a special stop apparatus arranged at a light source plane position on an exit side of said uniforming optical system,
• a second focusing optical system for focusing the light obtained through said special stop and radiating the light onto said mask, and
• a projection optical system for projecting the light, transmitted through said mask, onto the wafer,
• wherein said special aperture stop is wherein said special aperture is defined by four circular regions which are symmetrical about the axis and decentered therefrom, and an annular region which connects the four circular regions together, said four circular regions having centers which are on a circle whose center coincides with an optical axis of the light.

A projection exposure apparatus for projecting/exposing a mask pattern formed on a mask onto a wafer through a projection optical system, comprising:

• a first aperture stop for adjusting light to set intensities of both peripheral and central portions to be larger than an intensity of an intermediate portion of an intensity distribution within an exit plane;
• a second aperture stop for adjusting light to set intensities in four regions, which are quadruple-symmetrical about an optical axis of said apparatus, and are decentered therefrom, are higher than intensities in other regions;
• and
• selecting means for selecting one of said first aperture and second aperture according to said mask pattern, and setting said selected aperture at a position of a secondary source to illuminating said mask.

A projection exposure apparatus for projecting/exposing a mask pattern formed on a mask onto a wafer through a projection optical system, comprising:

• a first aperture stop for adjusting light to set intensities of both peripheral and central portions to be larger than an intensity of an intermediate portion of an intensity distribution within an exit plane;
• a second aperture stop for adjusting light to set intensities in four radially large regions, which are quadruple-symmetrical about an optical axis of said apparatus, and are decentered therefrom, are higher than intensities in other regions, and for adjusting the light to set intensities in radially small regions connecting said four regions, said radially large regions having centers coinciding with a concentric circle having an optical axis of the light as a center;
• and
• selecting means for selecting one of said first aperture and second aperture according to said mask pattern, and setting said selected aperture at a position of a secondary source to illuminating said mask.