Conquering the single digit nm

Block Copolymers. Credit: University of Wisconsin-Madison

Transistor gate length (Lg), over time. The plateau was between 45nm and 28nm, until Intel’s 22nm FinFET (thin channel transistor) kicked in. Credit: Applied Materials

The furthering of the Moore's law in a struct sense (doubling the number of transistors on a chip of a given size) requires shrinking the size of each transistor and in turns the size of the etching. We have reached in 2014 the 14nm scale. Shrinking further to the single digit nm scale needs new etching technology. What researchers are looking at is the Extreme Ultraviolet Lithography, EUV. 

The problem is that in spite of the huge amount of money spent in research effective EUV is still not available.  Hence, scientists are starting to look at alternative technology for etching wafer.

One of this leverages on an interesting property of block copolymers. Researchers at IMEC, a research centre in Leuven, Belgium, are looking to exploit the self assembling capability shown by block copolymer.

Block copolymers, as their name implies, are compound existing in blocks that tend to remain separate from one another, as it happens when you pour oil in water. They don't mix. However, if the copolymers are layered onto a grid they will replicate the grid pattern at a finer scale. Where the regional grig has one square the block copolymer dispose themselves to form many squares, effectively replicating the original grid with finer resolution.

The idea is then to use this finer grid as a guide to etch the wafer thus resulting in smaller details, in the single digit nanometer.

Researchers keep working on EUV but now it is a race to see what technology may first become commercially available for the next chip generation targeted by the end of this decade.

 

Author - Roberto Saracco

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