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Photomasks are key elements of photolithographic processes, implying that their degradation must be reliably monitored
and strongly mitigated. Indeed, the photo-induced oxidation of Cr in Cr On Glass (COG) photomasks and the
concomitant electrostatic-field migration present in high-volume production using 193-nm photolithographic scanners
severely deteriorate the pattern transfer quality, therefore limiting the lifetime of these reticles. To moderate this effect,
Opaque MoSi On Glass (OMOG) photomasks, significantly less prone to such degradation, are currently being
massively used in leading-edge microfabrication flows. The type of mask fabrication process normally used involving ebeam
writing is however not adapted for non-critical photolithographic layers that do not yet benefit from its inherent
performances but still suffer from its high cost and its long processing time. It is therefore proposed in this work to
combine the simplicity of laser writing and the resistance of MoSi to degradation by using laser-written binary OMOG
photomasks for the non-critical layers (e.g. ion-implantation) of a 28-nm production flow. To evaluate one of this new
reticle, its pattern transfer fidelity is compared to the one of a laser-written binary COG mask already qualified for
production from a photolithographic quality perspective, both masks being treated using the same optical proximity
correction (OPC) model. Dispersive and dissipative properties, critical dimension uniformity, pattern linearity and
pattern proximity are directly measured on wafer level, subsequently revealing that both photomasks match in terms of
OPC parameters. The utilized OPC model is moreover proven robust against the use of both types of masks,
consequently making the conversion from COG to OMOG particularly simple. These experimental results therefore
qualify the new mask fabrication type and pave the way for a major utilization in high-volume production.
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