| 摘要 |
An ATOM lithographic mask includes a transparent substrate having a pattern of attenuated phase shifters and a diffraction grating aligned with the attenuated phase shifters. The attenuated phase shifters form the primary mask pattern, while the diffraction grating diffracts exposure energy directed through the mask to provide off axis illumination for the attenuated phase shifters. The diffraction grating includes chromeless phase shifters formed using an additive or subtractive process. Both the attenuated phase shifters and diffraction grating can be formed as simple line-space patterns or in other patterns as required. In an alternate embodiment the diffraction grating is formed on a separate mask.
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