Source-collector modules for EUV lithography employing a GIC mirror and a LPP source

A source-collector module (SoCoMo) apparatus for an extreme ultraviolet (EUV) lithography system, comprising:

• a grazing-incidence collector (GIC) having an optical axis, an input end and an output end, with an intermediate focus adjacent the output end;
• a low-mass target residing along the GIC optical axis at a first location;
• at least a first laser operably arranged to generate at least a first light pulse of first infrared (IR) radiation to the first location to irradiate the low-mass target to substantially vaporize and ionize the low-mass target to form an initial plasma, wherein the initial plasma reflects a portion of the first IR radiation to form first reflected IR radiation;
• at least a second laser operably arranged to generate at least a second light pulse of second IR radiation to irradiate the initial plasma to form a final plasma having an EUV-emitting region that substantially isotropically emits EUV radiation, wherein the final plasma reflects and a portion of the second IR radiation to form second reflected IR radiation;
• a first debris mitigation device (DMD) operably arranged between the final plasma and the GIC;
• a multilayer-coated spherical mirror arranged along the GIC optical axis adjacent the low-mass target and opposite the GIC and focused on the EUV-emitting region so that the multi-layer coated spherical mirror receives a portion of the emitted EUV radiation and directs it back to the EUV-emitting region to travel through the DMD and then to the input end of the GIC;
• wherein the at least first and at least second lasers are arranged relative to the low-mass target and the GIC mirror such that at least the second reflected IR radiation is not directed towards either the GIC mirror or the spherical mirror and remains substantially uncollected by the GIC mirror and by the spherical mirror.