US 5,514,247 A · Process for plasma etching of vias

Abstract

Disclosed is a process for plasma etching a mask patterned dielectric film to form vias on a semiconductor wafer, so that the resulting etched structure is devoid of residues on the walls of the structure. A via is an opening through a dielectric material through which a point of contact of underlying metal with a metal film deposited over the dielectric is made. The underlying metal, when exposed to plasma, has a tendency to sputter onto the vertical wall portions of the contact via structures. The metal-containing sputtered material forms a residue that essentially cannot be removed in the subsequent photoresist stripping process typically used in semiconductor manufacturing. The plasma etch process in accordance with the invention enables removal of the sputtered metal by utilizing with the basic dielectric etch gases a gas that reacts with the metal to form volatile compounds which are readily evacuable.

Claims26

Dependent claims

A method for etching vias within a patterned dielectric film positioned over an underlying film of metal, comprising the steps of:

placing a substrate containing a patterned dielectric film positioned over an underlying metal film to be etched onto a support platform within a plasma etch reactor:
maintaining a vacuum within the reactor chamber;
admitting gases into the reactor chamber for plasma etching the dielectric film;
admitting one or more gases into the reactor chamber capable of reacting with the underlying metal film to form readily volatilized compounds within the subatmospheric pressure environment of the plasma etch reactor chamber:
and
forming a plasma of said gases to etch the patterned dielectric film selectively with respect to the underlying metal, while removing sputtered deposits from the underlying metal on the vertical wall portions of the etched via structures, whereby the vias are suitable for accepting metal to form contacts between the underlying metal film and any subsequently deposited overlying metal film.

3 more elements

Dependencies are inferred from the claim text.

Process for plasma etching of vias

Life of this patent

Process for plasma etching of vias

Life of this patent

Abstract

Claims26