Illumination system and projection exposure apparatus using the same

An illumination system for illuminating an illumination region having a difference in size along a first direction and a second direction perpendicular to the first direction, said illumination system comprising:

• an optical integrator including elements having different refractive powers with respect to the first and second directions as said optical integrator is viewed in an optical axis direction, said elements also having the same pitch with respect to the first and second directions;
• and
• optical means for directing light from a light source upon said optical integrator, at different numerical apertures with respect to the first and second directions, so as to satisfy a relation
• 0.8<[(NA1/NA2)/(φ1/φ2)]<1.2
• where NA1 and NA2 are numerical apertures of the light incident on said optical integrator with respect to the first and second directions, and φ1 and φ2 are refractive powers of said optical integrator with respect to the first and second directions.

An illumination system for illuminating an illumination region having a difference in size along a first direction and a second direction perpendicular to the first direction, said illumination system comprising:

• an optical integrator for receiving light from a light source, said optical integrator having (i) a first lens assembly including cylindrical lenses arrayed at a predetermined pitch along the first direction, said cylindrical lenses of said first lens assembly having a refractive power only with respect to the first direction, and (ii) a second lens assembly including cylindrical lenses arrayed at a predetermined pitch along the second direction, said cylindrical lenses of said second lens assembly having a refractive power only with respect to the second direction, wherein said first and second lens assemblies are disposed along the optical axis direction and when said first and second lens assemblies are viewed in the optical axis direction, said cylindrical lenses of said first and second lens assemblies are mutually intersected to define plural elements having the same pitch with respect to the first and second directions;
• and
• optical means for directing light from a light source to said optical integrator, at different largest incidence angles with respect to the first and second directions, so as to satisfy a relation
• 0.8<[(tan θ1/tan θ2)/(φ1/φ2)]<1.2
• where θ1 and θ2 are largest incidence angles of the light incident on said optical integrator with respect to the first and second directions, and φ1 and φ2 are refractive powers of said optical integrator with respect to the first and second directions.