US Patent 7405156 - Nanoparticle ink patterning using reversed tapered photoresist

http://www.freepatentsonline.com/7405156.html

Conventional fabrication processes for patterning used in semiconductor manufacturing often involves low pressure and/or high temperature systems which can add significant cost to the process. Printing processes such as roll-to roll processing and inkjet printing have been increasingly used in recent years to provide cheaper alternatives. This patent from NEC teaches using nanoparticles in a printing process to pattern tapered wiring structures. Claim 1 reads:

1. A method of forming a wiring pattern on an insulating substrate using a nanoparticles-containing ink, comprising:

partitioning the insulating substrate into wiring regions using a photoresist film; and

drawing the wiring pattern on the insulating substrate by injecting the ink thereon, the ink comprising metallic nanoparticles, wherein patterns of the photoresist film which partition the insulating substrate into the wiring regions comprise a reverse tapered cross section, and wherein said drawing of said wiring pattern comprises leveling the ink formed on the wiring regions.