Patent ID: 7091505

Claim:
A projection exposure system operable in a scanning mode along a scanning direction, comprising: a collector that receives light having a wavelength ≦193 nm and illuminates a region in a plane , wherein said plane is defined by a local coordinate system having a y-direction parallel to said scanning direction and an x-direction perpendicular to said scanning direction, wherein said collector comprises: (a) a first mirror shell; (b) a second mirror shell within said first mirror shell, wherein said first mirror shell and said second mirror shell are substantially rotational symmetric about a common rotational axis; and (c) a fastening device for fastening said first mirror shell and said second mirror shell, wherein said fastening device has a support spoke that extends in a radial direction of said first and said second mirror shells, and wherein said support spoke, when projected into said plane, yields a projection that is non-parallel to said y-direction.