Method of preventing damage to porous low-k materials during resist stripping
A method of forming a feature in a porous low-K dielectric layer is provided. A porous low-K dielectric layer is placed over a substrate. A patterned photoresist mask is placed over the porous low-K dielectric layer. A feature is etched into the porous low-K dielectric layer. A protective layer is deposited over the feature after the etching the feature. The patterned photoresist mask is stripped, so that part of the protective layer is removed, where protective walls formed from the protective layer remain in the feature.
1. A method of forming a feature in a porous low-K dielectric layer, comprising:
placing a porous low-K dielectric layer over a substrate;
placing a patterned photoresist mask over the porous low-K dielectric layer;
etching a feature into the porous low-K dielectric layer;
depositing a protective layer over the feature after the etching the feature; and
stripping the patterned photoresist mask, so that part of the protective layer is removed,
where protective walls formed from the protective layer remain in the feature.
2. The method, as recited in claim 1 , further comprising placing a cap layer over the porous low-K dielectric layer before placing the photoresist mask, wherein the photoresist mask is placed over the cap layer.
3. The method, as recited in claim 2 , further comprising depositing a deposition layer over the protective walls.
4. The method, as recited in claim 3 , further comprising forming an antireflective coating over the cap layer before placing the photoresist mask, wherein the photoresist mask is placed over the antireflective coating.
5. The method, as recited in claim 1 , wherein the depositing the protective layer comprises depositing a fluorine free layer.
6. The method, as recited in claim 1 , wherein the depositing the protective layer further comprises depositing a polymer layer.
7. The method, as recited in claim 6 , wherein the protective layer is between 100 Å to 1500 Å thick.
8. The method, as recited in claim 7 , wherein the depositing the polymer layer comprises providing deposition gases of C 2 H 4 and O 2 .
9. The method, as recited in claim 7 , wherein the stripping comprises providing a stripping gas selected from at least one of hydrogen, nitrogen, ammonia and oxygen.
10. The method, as recited in claim 1 , wherein the porous low-K dielectric layer comprises nanometer size pores.
11. The method, as recited in claim 1 , wherein the stripping comprises using ion bombardment.
12. The method, as recited in claim 11 , wherein the ion bombardment removes top layers of the protective layer, but leaves protective sidewalls formed by the protective layer.
13. The method, as recited in claim 1 , wherein the deposition layer deposited over the protective walls is a barrier layer.
14. The method, as recited in claim 1 , further comprising placing the substrate in an etch chamber, wherein the etching, the depositing the protective layer, and the stripping the patterned photoresist mask are done in situ within the etch chamber.
15. A method of forming a feature in a porous low-K dielectric layer over a substrate and disposed below a patterned photoresist mask, comprising:
etching a feature into the porous low-K dielectric layer through the photoresist mask;
depositing a protective layer over the feature after the etching the feature; and
stripping the patterned photoresist mask, so that part of the protective layer is removed,
where protective walls formed from the protective layer remain in the feature.
16. The method, as recited in claim 15 , wherein the depositing the protective layer further comprises depositing a polymer layer.