US 6,386,212 B1 · Method of cleaning mixed material surfaces

Abstract

A composite surface at which at least two materials having different isoelectric points are exposed is cleaned by an HF dip, followed immediately by a dip in a low pH surfactant, followed by an optional rinse in deionized water, followed by a dip in ammonium hydroxide, followed immediately by a dip in a high pH surfactant, and followed by a rinse in deionized water. By maintaining the relatively extreme pH levels of the immediately preceding steps, the surfactant dips significantly prevent the formation of a charge differential between the different portions of the composite surface, which charge differential would otherwise tend to cause any particles present to remain on one portion of the composite surface or the other. The surfactant properties of surfactant dips help remove any particles from the composite surface, resulting in substantial removal of particles from the composite surface.

Claims24

Dependent claims

A method for cleaning a composite surface having at least two surfaces of different materials, said method comprising:

exposing the composite surface to hydrofluoric acid;
after said exposure of the composite surface to said hydrofluoric acid, exposing the composite surface to a surfactant acid, different from the hydrofluoric acid, and having a pH from about 1 to about 4;
after said exposure of the composite surface to said surfactant acid, exposing the composite surface to ammonium hydroxide;
after said exposure of the composite surface to said ammonium hydroxide, exposing the composite surface to a surfactant base, different from the ammonium hydroxide, and having a pH from about 8 to about 10;
and
after said exposure of the composite surface to said surfactant base, exposing the composite surface to deionized water.

3 more elements

A method for cleaning a first dielectric material and a second dielectric material in an electrical device including a plurality of electrically conductive structures upon a semiconductor substrate, each said electrically conductive structure having thereon the first dielectric material having a first dielectric constant, said electrical device also including the second dielectric material formed over the plurality of electrically conductive structures having a second dielectric constant that is lower than said first dielectric constant, comprising:

exposing co-planar surfaces on each of said first and second dielectric materials by chemical mechanical planarization;
exposing the co-planar surfaces to a hydrofluoric acid solution;
after said exposure of the co-planar surfaces to said hydrofluoric acid solution, exposing the co-planar surfaces to a surfactant acid solution, different from the hydrofluoric acid solution, and having a pH from about 1 to about 4;
after said exposure of the co-planar surfaces to said surfactant acid solution, exposing the co-planar surfaces to an ammonium hydroxide solution;
after said exposure of the co-planar surfaces to said ammonium hydroxide solution, exposing the co-planar surfaces to a surfactant base solution, different from the ammonium hydroxide solution, and having a pH from about 8 to about 10;
and
after said exposure of the co-planar surfaces to said surfactant base solution, exposing the co-planar surfaces to deionized water.

4 more elements

Dependencies are inferred from the claim text.

Method of cleaning mixed material surfaces

Life of this patent

Method of cleaning mixed material surfaces

Life of this patent

Abstract

Claims24