Lithographic objective having a first lens group including only lenses having a positive refractive power

A projection exposure system for microlithography, the system comprising:

• a light source for providing radiation needed for a projection exposure;
• a projection objective mounted downstream of said light source;
• and,
• said projection objective including:
• an object plane;
• a first lens group of positive refractive power directly adjacent said object plane and said first lens group having a number of lenses of positive refractive power;
• a second lens group of negative refractive power;
• at least one additional lens group having positive refractive power and said one additional lens group having a diaphragm mounted therein;
• said first lens group including only lenses having positive refractive power;
• said one additional lens group having a number of lenses of positive refractive power arranged forward of said diaphragm;
• and,
• the number of lenses of positive refractive power of said first lens group being less than the number of lenses of positive refractive power of said one additional lens group arranged forward of said diaphragm.

A method for making a microstructured component utilizing a projection exposure system including a light source for emitting ultraviolet laser light;

• and, a projection objective defining an optical axis and mounted downstream of said light source;
• said projection objective including;
• an object plane;
• a first lens group of positive refractive power directly adjacent said object plane and said first lens group having a number of lenses of positive refractive power;
• a second lens group of negative refractive power;
• at least one additional lens group having positive refractive power and said one additional lens group having a diaphragm mounted therein;
• said first lens group including only lenses having positive refractive power;
• said one additional lens group having a number of lenses of positive refractive power arranged forward of said diaphragm;
• and, the number of lenses of positive refractive power of said first lens group being less than the number of lenses of positive refractive power of said one additional lens group arranged forward of said diaphragm;
• and, the method comprising the steps of:
• introducing a mask containing a pattern between said light source and said projection objective on said optical axis;
• placing a substrate having a light-sensitive layer on said optical axis downstream of said projection objective;
• exposing said layer with said laser light through said mask;
• and,
• developing said light-sensitive layer and structuring said substrate in correspondence to said pattern of said mask.