EUV and NanoImprint at Advanced Lithography 2015
February 2015 – The SPIE Advanced Lithography conference in San Jose featured 7 technical track conferences in one venue. The primary focus was on two tracks: (1) the highly anticipated arrival of EUV [Extreme Ultraviolet] lithography [Conference 9422] and (2) Alternative Lithography Technologies [Conference 9423]. The EUV track has 14 sections covering viability and need for the technology through masks, resist chemistry, metrology, inspection, manufacturing and exposure/throughput. The Alternative Litho technology track also had 14 sections and covered DSA [Directed Self Assembly], NI [Nano Imprint], single and multi-beam E-Beam systems, and their design chains.
EUV has been sought after as the successor to 193nm stepper technology which would simplify the imaging of semiconductor devices below 180nm. Moore’s law has driven process technology down to the 14nm node, and the EUV solution has still not appeared as a viable alternative. The technology now has the pieces of a complete ecosystem, photoresists for the light source, mask making techniques, mask repair and inspection techniques, metrology methods and manufacturing flows. What is lacking is the source power and throughput necessary to make the technology viable. The methods that are needed for EUV have a cost and a flow turnaround that is not at the pace of standard methods, even with the overhead of multi-patterning (needing multiple masking steps for processing and resolving a single layer in the silicon processing flow). The conference when in details on the technology, optics, and chemistry of the steps in the EUV flow, however the lithography solution is still limited to the R&ED and pilot lines at this time.
The Alternative Lithography track started with DSA. This technology is still targeted at semiconductor applications and is being heavily looked at for the sub 10nm nodes. The tech is on the cusp of moving from R&D/Pilot line to production applications, and should be applicable for certain process steps at the 7nm node. The discussion focused on both lines and via patterning.
The e-beam discussions were on direct write and direct write of materials with simultaneous multiple beams. The e-beam technology faces some of the same issues as EUV and that is throughput related to source power and speed of pattern creation. The issues were being addressed for both mask creation and direct write on wafers.
NanoImprint technology is a lower cost, high through alternatives to EUV and e-beam. While the images are not as small, the throughput and flexibility of materials that can be printed and the cost of the “mask” make it a viable alternative. The papers were presented for printing for semiconductors, decorative printing on injection molded plastics, printing on substrates in PV applications, as well assisting ion beam writing for masks.
