Mask aligner lithography using laser illumination for versatile pattern generation.

Mask aligner lithography is a well-established back-end fabrication process in microlithography. Within the last few years, resolution enhancement techniques have been transferred and adapted from projection lithography to further develop mask aligner lithography, especially concerning achievable resolution. Nonetheless, current technology using a mercury vapor lamp as a light source has reached its limits, e.g. for high-resolution pattering. Within this paper, we present the extension of the existing mask aligner illumination system by replacing the mercury vapor lamp with a solid-state laser. Full-field mask aligner lithography is guaranteed by a rotating diffuser expanding the laser beam and minimizing undesired speckle effects. An additional integrated galvanometer scanner allows a flexible choice of arbitrary angular spectrum distributions of the photomask illumination. We show versatile results like simple binary patterns of squares and triangles, as well as a more complex lateral shape like a blazed grating.

Monolithic double-grating phase mask for large-period highly coherent grating printing.

A monolithic double-grating phase mask comprising three short-pitch grating sections of spatial frequencies k(1) and k(2) collocated at one side of a substrate produces a large-period interferogram without higher harmonics to print in a photoresist film a latent grating of small spatial frequency equal to twice k(2)-k(1). When incorporated in a write-on-the-fly scheme, the elements permit the fabrication of unlimitedly long gratings.

[Chronic venous insufficiency 7 to 10 years after partial vena cava interruption with a clip]. / Insuffisance veineuse chronique 7 à 10 ans après interruption partielle de la veine cave inférieure par clip exocave.

In order to test the responsibility of inferior vena cava clips in post thrombotic venous disease, we performed a comparative retrospective study 7 to 10 years after vena cava interruption by clip. Patients were compared with patients matched for sex, age, and prior deep vein thrombosis (same period and same localisation) but without inferior vena cava partial interruption. The results show that 1) functional complaints were significantly higher in the vena cava clip group; 2) valvular incompetency, in the initially thrombosed leg, (tested by scanning duplex) was not different in the two groups: 3) inversely, on the other leg, valvular incompetency was greater in the vena cava clip group. Furthermore this valvular incompetency was principally located at a femoral level, suggesting that the vena cava clip may induce backward thrombosis; 4) complications were independent of vena cava thrombosis.