초록 ▼

A method of minimizing RIE lag (i.e., the neutral and ion fluxes at the bottom of a deep trench (DT) created during the construction of the trench opening using a side wall film deposition)) in DRAMs having a large aspect ratio (i.e., <30:1) is described. The method forms a passivation film to the e

A method of minimizing RIE lag (i.e., the neutral and ion fluxes at the bottom of a deep trench (DT) created during the construction of the trench opening using a side wall film deposition)) in DRAMs having a large aspect ratio (i.e., <30:1) is described. The method forms a passivation film to the extent necessary for preventing isotropic etching of the substrate, hence maintaining the required profile and the shape of the DT within the substrate. The RIE process described provides a partial DT etched into a substrate to achieve the predetermined depth. The passivation film is allowed to grow to a certain thickness still below the extent that it would close the opening of the deep trench. Alternatively, the passivation film is removed by a non-RIE etching process. The non-RIE process that removes the film can be wet etched with chemicals, such as hydrofluoric acid (buffered or non buffered) or, alternatively, using vapor phase and/or non-ionized chemicals, such as anhydrous hydrofluoric acid. The controlled thickness of the film allows achieving a predetermined DT depth for high aspect ratio structures.

대표청구항 ▼

[ Having thus described the invention, what is claimed as new and desired to secure by Letters Patent is as Follows:] [1.]1. A method of etching high aspect ratio trenches in a semiconductor device comprising the steps of:depositing a hardmask on a substrate;patterning said hardmask;using said hardm

[ Having thus described the invention, what is claimed as new and desired to secure by Letters Patent is as Follows:] [1.]1. A method of etching high aspect ratio trenches in a semiconductor device comprising the steps of:depositing a hardmask on a substrate;patterning said hardmask;using said hardmask, etching said substrate with a substantially directional etch process to form a trench, said etch process resulting in a deposition of a passivation layer interior to said trench; andrepeatedly etching said substrate a) under varied process conditions to partially remove said passivation layer, and b) with said substantially directional etch process, such that said etching etches said trench to an aspect ratio.