Photomask features with interior nonprinting window using alternating phase shifting
AssigneeSanDisk 3D LLC
InventorYung-Tin Chen
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Abstract
Aspects of the present invention provide for a novel photomask for patterning features for an integrated circuit, the photomask including masked features having interior nonprinting windows. In some embodiments, the interior nonprinting window is an alternating phase shifter, while the area surrounding the masked features transmits light unshifted. In other embodiments, the interior nonprinting window transmits light unshifted, while the area surrounding the masked features is an alternating phase shifter. Thus any arrangement of features can be patterned with no phase conflict.
Claims51
A photomask for patterning fine features comprising:
- a first masked feature;
- a first transmitting nonprinting window substantially entirely enclosed within a perimeter of the first masked feature;
- and
- a first transmitting area substantially entirely surrounding the perimeter of the first masked feature in the plane of the photomask, wherein
- light transmitted through the first window, after transmission through the first window, is in a first phase, and
- light transmitted through the first transmitting area, after transmission through the first transmitting area, is in a second phase substantially opposite the first phase.
A photomask for patterning fine features comprising a first nonprinting alternating phase shifter wherein:
- light transmitted through the photomask reaching a photoresist surface substantially entirely within a perimeter of a projected photoresist feature is in a first phase, and
- light reaching a photoresist surface outside and in proximity to the perimeter of the projected photoresist feature, on all sides of the projected photoresist feature, is in a second phase substantially opposite the first phase.
A photomask for patterning fine features comprising a first nonprinting alternating phase shifter, the phase shifter substantially entirely enclosed within a perimeter of a first masked feature.
A photomask for patterning fine features comprising:
- a first nonprinting transmitting window substantially entirely enclosed within a perimeter of a first masked feature;
- and
- a transmitting area substantially entirely surrounding and in proximity to the perimeter of the first masked feature in the plane of the photomask, wherein the transmitting area operates as a first alternating phase shifter.
Dependencies are inferred from the claim text.