In recent years, researchers have begun to look at block copolymers, an organic material that is compatible with conventional semiconductor manufacturing processes, because a thin film of it, under the right conditions, can self-assemble into regular arrays of holes on the order of 20nm or smaller in diameter. This tiny, self-assembled swiss cheese of block copolymer can act as a stencil for creating electrical contacts to very small semiconductor devices.
Previous attempts at using block polymers have fallen short because the self-assembled holes were not aligned to existing electrical features on the semiconductor wafer. Now, the SRC-sponsored work by researchers from Stanford University and TSMC has produced the industry’s first functional devices and circuits that employ diblock copolymer patterning for sub-22nm CMOS technologies on a full wafer scale.
“We believe this development will help to bring self-assembly closer to broad application in the semiconductor industry and will help increase the use of nanotechnology for advancements in electronics for years to come,” said H.-S. Philip Wong, a professor of Electrical Engineering at Stanford University.
The research is expected to catalyze further innovations in the area of extensible nanomanufacturing and possibly be integrated into the manufacturing process in the next seven to 10 years.
More information about the research and results will be published in a paper entitled “Top-Gated FETs/Inverters with Diblock Copolymer Self-Assembled 20nm Contact Holes” and presented at IEEE’s 2009 International Electron Devices Meeting in Baltimore, Md., on December 9. The paper is co-authored by graduate student, Li-Wen Chang and H.-S. Philip Wong of Stanford University, and T.L. Lee, Clement H. Wann, and C.Y. Chang of TSMC
copolymer at wikipedia
A heteropolymer or copolymer is a polymer derived from two (or more) monomeric species, as opposed to a homopolymer where only one monomer is used. Copolymerization refers to methods used to chemically synthesize a copolymer.
Commercially relevant copolymers include ABS plastic, SBR, Nitrile rubber, styrene-acrylonitrile, styrene-isoprene-styrene (SIS) and ethylene-vinyl acetate.
Diblock copolymer articles at Stanford
Lithography with a mask of block copolymer microstructures, J. Vac. Sci. Technol. B Volume 16, Issue 2, pp. 544-552 (March 1998)
Ultrahigh-Density Nanowire Arrays Grown in Self-Assembled Diblock Copolymer Templates (2000)