Patent Number: 053393465
Section: claims

1. Process for fabrication of a device comprising at least one element of least dimension .ltoreq.0.25 .mu.m, such process comprising construction of a plurality of successive levels, each level entailing lithographic delineation, in accordance with which a subject mask pattern is imaged on an image plane, ultimately to result in removal of or addition of material in delineated regions, at least one such level entailing ringfield projection lithographic delineation by use of radiation in the soft x-ray spectrum, and in which such radiation is derived from a laser-produced plasma characterized in that emission from the plasma is collected by a collector lens including at least four paired mirror facets, in which members of each pair are symmetrically disposed about an axis of the source and in which paired members individually produce complementary images of the entirely of an illumination field, whereby paired members together produce an evenly illuminated compensated field and the entire illumination field is of an intensity which is the sum of all facet-produced image fields. 2. Process of claim 1 in which the collector lens is the first lens of a condenser which includes at least one processing lens. 3. Process of claim 2 in which the condenser includes a first processing lens which is faceted, in which the number of facets in the first processing lens is equal to the number of facets in the collector lens, and in which images yielded by collector lens facets are incident upon individual dedicated facets of the first processing lens. 4. Process of claim 2 in which the one processing lens contributes to shaping of the illumination field into the arc-shaped form required for ringfield projection. 5. Process of claim 2 in which the condenser includes filter means for reducing the plasma-emitted radiation spectrum of .lambda.=100 .ANG.-200 .ANG., and in which the means consist essentially of an MLR condenser lens. 6. Process of claim 5 in which the MLR condenser lens is the collector lens. 7. Process of claim 1 in which ringfield lithographic delineation entails subject:image size reduction. 8. Process of claim 7 in which the condenser includes at least two processing lenses intermediate the collector lens and the mask, the processing lenses together functioning to direct and shape the ringfield illumination field. 9. Process of claim 8 in which member facets of at least one pair of the collector lens are curved. 10. Process of claim 9 in which the curved member facets are ellipsoidal. 11. Process of claim 10 in which the curved member facts are of Lopez curvature. 12. Process of claim 1 in which paired facet tiers are two-membered. 13. Process of claim 2 in which paired members are tilted so that illumination from the collector lens forms two separated series of images. 14. Process of claim 13 in which illumination as incident on the camera pupil is quadrupole. 15. Process of claim 2 in which the condenser includes an adjustable real aperture of adjustability sufficient to block some of the radiation. 16. Process of claim 15 in which an adjustable real aperture is positioned immediately subsequent to a first processing lens. 17. Device as produced by any of claims 1,2,3,4,5,6,7,8,9,10,11,12,13, 14,15 or 16.