Tufts University investigators have developed a lithography resist that eliminates minimizes the use of harsh chemicals without sacrificing resolution. Optical-grade silk fibroin aqueous solution obtained from the cocoons of the Bombyx mori caterpillar is placed on a substrate and spin-coated to form a silk film.

Competitive Advantages

Eliminates special wastewater treatment

For positive resist work the film is crosslinked, but for negative resist, this step is skipped and the film is left in its uncrosslinked state. Electron-beam exposure on selected areas either crosslinks or de-crosslinks silk fibroin molecules. Water can then be used to wash away the water-soluble (uncrosslinked) areas.

Applications

•       IC circuits

•       MEMS devices

•       Flexible electronics – sensors and IC circuits

Photoresists (novolak resins) used in lithography for the fabrication of ICs and MEMS devices are known carcinogens requiring special equipment to treat wastewater.

Competitive Advantage.  The resist is a biocompatible and biodegradable biopolymer allowing more economical wastewater treatment and minimizes health risks.

Intellectual Property

US Publication No. 2016-0033861 (Published February 2, 2016)

Licensing Contact

Martin Son
martin.son@tufts.edu