HIGH-RESOLUTION SILICON PATTERNING WITH SELF-ASSEMBLED MONOLAYER RESISTS

Single crystal and polycrystalline silicon films have been patterned a nd etched with a novel high-selectivity process using self-assembled m onolayer resists of octadecylsiloxanes (ODS). The highest resolution p atterning of sub-10 nm features has been demonstrated by scanning forc e microscopy imaging of ODS layers patterned with a focused electron b eam. An all-dry UV/ozone developer has been used to remove residual ca rbon from the electron beam exposed regions to improve etch selectivit y. The positive tone pattern transfer process consisted of a short buf fered hydrofluoric acid wet etch to remove the silicon native oxide fo llowed by a high-selectivity, low ion energy etch using Cl-2 and BCl3 in an electron cyclotron resonance reactive ion etch. Features have be en etched up to 90 nm deep into Si(100) wafers and minimum feature siz es obtained are similar to 25 nm. Poly-Si films on SiO2 insulator laye rs have been similarly patterned and have been used in a combined proc ess with photolithographic definition of microbridges to form narrow c onducting channels in the poly-Si. (C) 1996 American Vacuum Society.