In the stress control of an X-ray mask absorber, the repeatability of control and stability are important. We found that the change in the stress in a Ta film resulting from annealing depends on the oxygen concentration in the film; the magnitude of the stress change is determined by the annealing temperature and time. Using this characteristic of Ta film, we have successfully controlled the stress in the Ta absorber to less than 5 MPa with good repeatability. In our mask fabrication process, Al2O3 film was used as an etching mask. We found that the Al2O3 film prevented the Ta absorber stress from changing in high-temperature atmospheres because the Al2O3 film prevented oxygen diffusion into the Ta film. Utilizing Al2O3 films, we succeeded in preventing changes in Ta absorber stress in the thermal processes after Ta stress control, such as frame bonding and resist baking. Consequently, we were able to precisely control the Ta absorber stress in X-ray masks with good repeatability and stability in a realistic X-ray mask fabrication process.

Using the techniques of pulse-radiolysis and of the absorption of Lyman-α radiation by hydrogen atoms, the absolute rate constants of reaction of hydrogen atoms with several olefins have been measured at room temperature. Olefin k⁄10−12 cm3 molecule−1 s−1 Ethylene 1.1±0.1 Propylene 1.7±0.1 1-Butene 2.0±0.5 trans-2-Butene 1.1±0.2 cis-2-Butene 1.0±0.1 2-Methyl-1-propene 5.2±0.6 2-Methyl-2-butene 2.4±0.3 These rate constants were invariant over hydrogen pressures ranging from 200 to 1200 Torr.

We have improved the M-Split complementary mask pattern split program and our electron projection lithography (EPL) data conversion system to achieve a practical data processing time and data volume. The system was designed to rehierarchicalize the data, flattened after the subfield split, by extracting polygons that all have an identical shape as a cell. The M-Split stress check function was improved by using a normalized bending moment as a criterion. A clustered computing system was used to reduce the data processing time. The processing time for a complementary mask pattern split without rehierarchicalizing was reduced to 57 min by using the stress check function and a ten PC cluster system −3–10 times as fast as with commercially available EPL data conversion systems. We successfully fabricated a full-size 8 in. Si stencil mask consisting of 8000 subfields using the data for an actual 70 nm design-rule system on chip device to demonstrate the effectiveness of M-Split. With a higher performance PC cluster system and the rehierarchicalizing, we expect to further reduce the M-Split processing time to 10 min.

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