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Critical to the success of imprint lithography and Step and Flash Imprint Lithography (S-FIL®) in particular is the
manufacturing 1X templates. Several commercial mask shops now accept orders for 1X templates. Recently, there have
been several publications addressing the fabrication of templates with 32nm and sub 32nm half pitch dimensions using
high resolution Gaussian beam pattern generators. Currently, these systems are very useful for unit process
development and device prototyping. In this paper, we address the progress made towards full field templates suitable
for the fabrication of CMOS circuits.
The starting photoplate consisted of a Cr hard mask (≤ 15nm) followed by a thin imaging layer of ZEP 520A. The
EBM-5000 and the EBM-6000 variable shape beam pattern generators from NuFlare Technology were used to pattern
the images on the substrates. Several key specifications of the EBM-6000, resulting in improved performance over the
EBM-5000 include higher current density (70 A/cm2), astigmatism correction in the subfields, optimized variable stage
speed control, and improved data handling to increase the maximum shot count limitation.
To fabricate the template, the patterned resist serves as an etch mask for the thin Cr film. The Cr, in turn, is used as
an etch block for the fused silica. A mesa is formed by etching the non-active areas using a wet buffered oxide etch
(BOE) solution. The final step in the template process is a dice and polish step used to separate the plate into four
distinct templates.
Key steps in the fabrication process include the imaging and pattern processes. ZEP520A was chosen as the e-beam
resist for its ability to resolve high resolution images. This paper documents the resolution and image placement
capability with the processes described above. Although ZEP520A is slow relative to chemically amplified e-beam
resists, it is only necessary to pattern 1/16th the area relative to a 4X reduction mask. Write time calculations for 1X
templates have also been performed, and are compared to 4X photomasks.
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