Projection x‐ray lithography using computer‐generated holograms: A study of compatibility with proximity lithography

X‐ray projection lithography has recently been explored as a method for the manufacture of ≤200 nm linewidth integrated circuits. A method was previously described [J. Appl. Phys. 71, 2993 (1992)] whereby projected lithographic images can be formed with x rays by means of a transmission hologram. The form of the hologram is computed by an algorithm which eliminates the unwanted signals normally present as systematic errors in in‐line holographic images. Such an approach to projection x‐ray lithography requires an x‐ray beam with very little coherence and is thus compatible with high wafer throughput schemes; in addition, image fidelity remains high even when moderately small contaminant particles block the light from small regions of the hologram. Previous example calculations involved using 5 nm x rays to illuminate a 0–1 μm thick carbon hologram located 200 μm from the wafer to produce simulated 0.06 μm linewidth images with good fidelity and with 6 μm depth of field. Presented here are simulations invo...