The history of semiconductor manufacturing is one of outstanding gains in productivity driven by the regular introduction of new devices requiring smaller critical dimensions. These smaller critical dimensions were enabled by new patterning options that were result of the introduction of new tools and new materials. With the advent of multiple patterning, it was shown that improved processes and resolution could multiply resolution by 2x or more without any exposure tool changes. This has changed the nature of the roadmaps for new patterning technologies.
Now a new patterning method can’t just enable better resolution, it must also provide a cost or design benefit to be implemented in place of multiple patterning.
Four potential new patterning methods are now undergoing substantial development efforts: EUV lithography, directed self-assembly, nanoimprint and mask less lithography. Each of these techniques has different development status, strengths and weaknesses, materials requirements and possible introduction points in manufacturing. The requirements for implementing these methods also depend on the progress of semiconductor device technology. If new device types can be produced that take advantage of smaller critical dimensions without unacceptable power consumption, defect rate or performance, this will enhance the need for the new technology.If the industry finds it more productive to stack devices in three dimensional arrays without shrinking the critical dimensions, then the usefulness of current patterning technology could be extended.
New patterning techniques were once thought of as hinging on the introduction of new types of tools, but new materials and processes proved to bring just as much improvement to resolution as new tools did. So whatever patterning technique is adopted for future semiconductor nodes, even if it is just the extension of multiple patterning, new materials will be needed. This is driven not only by the nature of the patterning technique to be used but also by the general nature of smaller features, thinner films and more complicated product design driving a need for better pattern fidelity and better defect control. Many materials have provided better lithographic processes in the past and more will be needed in the future.
Keywords: Phtotoresist, Electronic materials, Next generation lithography, Semiconductor patterning