HIGH-SELECTIVITY PATTERN TRANSFER PROCESSES FOR SELF-ASSEMBLED MONOLAYER ELECTRON-BEAM RESISTS

Novel processes have been developed for transferring patterns using se lf-assembled monolayer (SAM) electron beam resists. Because the SAMs a re very thin, high-selectivity processes are required for effective su bstrate modification. Two separate techniques have been studied for pa tterning intermediate layers for use as reactive ion etch (RIE) masks. A bilayer process using the native oxide as an intermediate etch mask has been used to etch into both crystalline and polycrystalline silic on. The native oxide is patterned with the SAM resist and the oxide is then used as a mask in an electron cyclotron resonance RIE. This proc ess has been used to produce similar to 25 nm etched features in silic on. Instead of its selective removal, an alternative technique for for ming the intermediate etch mask layer is the selective deposition of t he layer. Thin nickel layers have been formed with an electroless plat ing technique on silicon. The electroless deposition is highly selecti ve for producing nickel plating on silicon as opposed to the silicon o xide. These novel high-selectivity techniques demonstrate the ability for ultrathin SAM resist layers to pattern silicon and other materials . (C) 1997 American Vacuum Society.