Metal/oxide etch after polish to prevent bridging between adjacent features of a semiconductor structure
View Patent ↗Methods for eliminating and/or mitigating bridging and/or leakage caused by the contamination of a dielectric layer with fragments and/or residues of a conductive material are disclosed. The methods involve exposing a semiconductor substrate with a dielectric layer contaminated with fragments and/or residues of conductive materials to one or more conductor and/or dielectric etches. The disclosure by eliminating and/or mitigating metal bridging and/or leakage can provide one or more of the following advantages: high device reliability, decreased manufacturing cost, more efficient metallization, and increased performance.
1. A method for mitigating one or more of bridging and leakage between adjacent features of a semiconductor structure, comprising:
forming openings in a dielectric layer formed over a semiconductor substrate;
depositing a conductive material over the semiconductive substrate and into the openings;
polishing the conductive material whereby at least one of fragments and residues of the conductive material contaminate the dielectric layer;
oxidizing the contaminated dielectric layer; and
exposing the semiconductor substrate to a dielectric etch to achieve selective removal of the contamination portion of the dielectric layer and to a conductive etch to achieve selective removal of the at least one of fragments and residues of conductive material without significantly removing the conductive material in the openings,
wherein the dielectric etch mitigates at least one of bridging and leakage between adjacent features.
2. The method of claim 1 , wherein the dielectric layer comprises silicon dioxide.
3. The method of claim 1 , wherein the dielectric etches comprise oxide etches.
4. The method of claim 1 , wherein etching is carried out for a time period from about 1 second to about 200 seconds.
5. The method of claim 1 , wherein etching is carried out for a time period from about 10 seconds to about 100 seconds.
6. The method of claim 1 , wherein the dielectric etch substantially removes only the contaminated portion of a dielectric layer without significantly removing either the uncontaminated portion of the dielectric layer or conductive materials.
7. The method of claim 1 , wherein the one or more etches comprise at least one of a plasma etch and a reactive ion etch.
8. The method of 1 , wherein the openings comprise at least one of vias, holes, contacts, metal lines, and trenches.
9. The method of claim 1 , wherein the conductive material comprises at least one selected from the group consisting of aluminum, chromium, copper, germanium, gold, magnesium, manganese, indium, iron, nickel, palladium, platinum, silver, titanium, zinc, tungsten, and alloys thereof.
10. The method of claim 1 , wherein polishing the conductive material comprises a chemical mechanical polishing.
11. The method of claim 1 , further comprising forming a barrier layer surrounding bottom and sidewalls of the openings.
12. A method for mitigating one or more of bridging and leakage between adjacent features in a damascene interconnect structure, comprising:
forming openings in a dielectric layer formed over a semiconductor substrate;
depositing a conductive material over the semiconductor substrate and into the openings;
polishing the conductive material whereby at least one of fragments and residues of the conductive material contaminate the dielectric layer;
oxidizing the contaminated dielectric layer; and
exposing the semiconductor substrate to a dielectric etch to achieve selective removal of the contamination portion of the dielectric layer and to a conductive etch to achieve selective removal of the at least one of fragments and residues of conductive material without significantly removing the conductive material in the openings,
wherein the dielectric etch mitigates one or more of bridging and leakage between adjacent features.
13. A method for mitigating at least one of bridging and leakage between adjacent features in a dual damascene structure, comprising:
forming a first dielectric layer formed over a semiconductor substrate;
depositing a middle etch stop layer over the first dielectric layer;
forming vias in the first dielectric layer;
forming a second dielectric layer over the middle etch stop layer covering the vias;
forming trenches in the second dielectric layer
depositing a conductive material into the vias and trenches;
polishing the conductive material whereby at least one of fragments and residues of the conductive material contaminate the dielectric layer;
oxidizing the contaminated dielectric layer; and
exposing the semiconductor substrate to a dielectric etch to achieve selective removal of the contamination portion of the dielectric layer and to a conductive etch to achieve selective removal of the at least one of fragments and residues of conductive material without significantly removing the conductive material in the vias and trenches,
wherein the dielectric etch mitigates one or more of bridging and leakage between adjacent features.
14. The method of claim 13 , further comprising forming the first dielectric layer over a bottom etch stop layer formed over the semiconductor substrate.
15. The method of claim 13 , wherein at least one of the first dielectric layer, the second dielectric layer, or a combination thereof comprises one or more selected from the group consisting of silicon dioxide, silicon nitride, low k dielectrics, high k dielectrics, spin-on-glass, and polymeric dielectrics.
16. The method of claim 13 , wherein the conductive material comprises at least one selected from the group consisting of aluminum, chromium, copper, germanium, gold, magnesium, manganese, indium, iron, nickel, palladium, platinum, silver, titanium, zinc, tungsten, and alloys thereof.
17. The method of claim 13 , wherein the conductive material comprises at least copper.
18. The method of claim 13 , further comprising forming a barrier layer around the vias, the trenches, and upper surfaces of the second dielectric layer.