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US 6,296,991 B1Granted
Bi-focus exposure process
AssigneeUnited Microelectronics Corp.
InventorBenjamin Szu-Min Lin
Life of this patent
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AssigneeUnited Microelectronics Corp.
InventorBenjamin Szu-Min Lin
Estimating the term…
A bi-focus exposure process for exposing a wafer through a mask is described. The mask comprises a plurality of first transparent hole features having a phase shift of about 0 degrees and a plurality of second transparent hole features having a phase shift of about 180 degrees, the first and the second hole features are alternatively located on a transparent substrate, and each of the hole features is substantially and adjacently surrounded by a lightly transparent material having a phase shift of about 90 degrees on the transparent substrate. The patterns of the first hole features are printed on the wafer by exposing the wafer through the mask at a first defocus smaller than 0 μm defocus. The patterns of the second hole features are printed on the wafer by exposing the wafer through the mask at a second defocus smaller than 0 μm defocus.
A bi-focus exposure process for exposing a wafer, comprising:
A process of exposing a wafer through a mask, wherein the mask comprises a plurality of first transparent hole features having a phase shift of about 0 degrees and a plurality of second transparent hole features having a phase shift of about 180 degrees, the first and the second hole features are alternatively located on a transparent substrate, and each of the first and the second hole features is substantially and adjacently surrounded by a lightly transparent material having a phase shift of about 90 degrees on the transparent substrate, which process comprises:
Dependencies are inferred from the claim text.