When an IC design has been physically verified and is past the
application of resolution enhancement technologies, such as optical
and process correction (OPC), the design is ready to move on to the
next step on the way to wafer manufacturing. That step is creation
of photomasks, the “negatives” that guide the patterns of light
used in wafer photolithography. Mask data preparation (MDP) is the
process that readies the circuit design data for delivery to mask
writing machines. Never clearly perceived as part of either of the
larger IC design or manufacturing communities, mask data
preparation has been traditionally orphaned between them. The race
to smaller feature sizes has pushed the photolithographic process
into the territory of sub-wavelength feature patterning.
Sub-wavelength patterning requires manufacturing processes capable
of creating design features smaller than the wavelength of the
light used to expose them. Over the past few years, the expanding
effects of s! maller feature sizes have led to development of
techniques for adapting and enhancing mask designs to ensure that
the patterns will print accurately. This has forced process
technology to use subwavelength and low K1 lithography as well as
adding RET and OPC to the design. Adding enhancements has in turn
expanded the volume of design data by as much as one or two orders
of magnitude.

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