Wednesday, August 26, 2009

US Patent 7579050 - Charged nanoparticle assisted lithography

Fabrication on the nanoscale is often divided between bottom-up and top-down strategies. However, there are some hybrid approaches which form an optimized medium between the nanoscale resolution available from the bottom-up approach and the fabrication speed available from the top-down approach. This patent represents one such hybrid approach based on a self-assembly of charged nanoparticles which enhance the resolution of a mask pattern, Claim 1 reads:

1. A method for patterning a nano-sized structure, which comprises the steps of:

(i) mounting a plate having a nano-scale pattern formed thereon by a patterned photoresist layer on an electrode placed in an externally grounded reactor and applying a voltage to the electrode, the nano-scale pattern being an exposed region of the plate uncovered by the photoresist layer;

(ii) accumulating charges selectively onto the photoresist layer on the plate mounted on the electrode by using an ionized gas; and

(iii) introducing charged nanoparticle aerosol having the same polarity as that of the charges accumulated on the photoresist layer into the reactor and toward the plate to cause the charged nanoparticles to adhere to the nano-scale pattern in a focused form to shape a narrower pattern than the original nano-scale pattern.