Litography is the current standard, well the only standard really, when it comes to making integrated circuits. Intel, IBM, UMC, TSMC, and the rest all use litography, but they are also all very well aware that the litography used today doesn’t have that many years left. The transistors are getting smaller and smaller, and silicon as an insulator is being stressed to the limit. The physical limitations of the material and the method are becoming painfully obvious.
Researchers at the National Institute of Standards and Technology have come up with an alternative approach. Recently they’ve published two articles on nanoimprint litography, one last fall and one this month (subscription required). Instead of etching the insulator using phototechnology, they’ve embossed it.
By lowering a stamp with nanopatterns into a soft film, and then heating the film, they were able to create delicate and relatively complex structures as small as 10nm in diameter. One of the big advantages of this process is that it allows for other insulators than silicon.
In the articles they’ve used spin-on organosilicate glass (SOG). SOG is a superior insulator, but it can’t be used with current litography methods as that would compromise the properties of the material. Nanoimprint litography not only makes it possible to use SOG, but actually makes it stronger in the process. When the material is heated it turns into a glass film laced with nanometer pores, which makes it an even better insulator.
Picture courtesy of NIST
Excerpt from the NIST Tech Beat:
“NIL, on the other hand, might be able to pattern SOG layers with wiring trenches and eliminate several time-consuming and expensive photolithography steps if it could pattern the film accurately and do so without destroying the delicate nanopore lacework.
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Using a combination of techniques to measure the distribution of nanopores in the insulator material, they found that the NIL embossing process actually has a beneficial effect—it increases the population of small pores, which improve performance, reduces the population of larger pores that can cause problems and creates a thin, dense protective skin across the surface of the material. All of these effects are highly attractive for minimizing short circuits in semiconductor devices.”
