Pattern formation method

1. A pattern formation method comprising the steps of:

a) forming an underlying layer film on a substrate;

b) forming an intermediate layer film on the underlying layer film;

c) forming a first resist film on the intermediate layer film and then performing exposure and development to the first resist film through a first photomask having a first pattern, thereby forming a first resist pattern;

d) etching the intermediate film using the first resist pattern as a mask, thereby forming a first intermediate layer pattern;

e) removing the first resist pattern;

f) forming, after the step e), a second resist film on the underlying layer film and the first intermediate layer pattern, and then performing exposure and development to the second resist film through a second photomask having a second pattern, thereby forming a second resist pattern;

g) etching the first intermediate layer pattern using the second resist pattern as a mask, thereby forming a second intermediate layer pattern;

h) removing the second resist pattern; and

i) etching, after the step h), the underlying layer film using the second intermediate layer pattern as a mask, thereby forming an underlying layer pattern including the first and second patterns,

wherein the underlying layer film is formed of an organic material having a resistance against oxygen-based plasma,

in the step e), the first resist pattern is removed by ashing with oxygen-based plasma, and the underlying layer film is formed of an organic material to which a fluorine-based surfactant is added.

2. The pattern formation method of claim 1 , wherein the fluorine-based surfactant locally concentrates around a surface of the underlying layer film.

3. The pattern formation method of claim 1 , wherein 10 to 30 wt % of the fluorine-based surfactant is added to the underlying layer film.

4. The pattern formation method of claim 1 , wherein the fluorine-based surfactant is an anionic fluorine-based or nonionic fluorine-based surfactant.

5. The pattern formation method of claim 4 , wherein the anionic fluorine-based surfactant is formed of one or more materials selected from the group consisting of perfluoroalkyl group-containing sulfonate, perfluoroalkyl group-containing carboxylate and perfluoroalkyl group-containing ester phosphate.

6. The pattern formation method of claim 4 , wherein the nonionic fluorine-based surfactant is formed of perfluoroalkyl ethylene oxide adduct.

7. The pattern formation method of claim 1 , wherein exposure in the step c) or the step f) is performed using KrF excimer laser light, Xe 2 laser light, ArF excimer laser light, F 2 laser light, KrAr laser light or Ar 2 laser light.

8. A pattern formation method comprising the steps of:

a) forming an underlying layer film on a substrate;

b) forming an intermediate layer film on the underlying layer film;

c) forming a first resist film on the intermediate layer film and then performing exposure and development to the first resist film through a first photomask having a first pattern, thereby forming a first resist pattern;

d) etching the intermediate film using the first resist pattern as a mask, thereby forming a first intermediate layer pattern;

e) removing the first resist pattern;

f) forming, after the step e), a second resist film on the underlying layer film and the first intermediate layer pattern, and then performing exposure and development to the second resist film through a second photomask having a second pattern, thereby forming a second resist pattern;

g) etching the first intermediate layer pattern using the second resist pattern as a mask, thereby forming a second intermediate layer pattern;

h) removing the second resist pattern; and

i) etching, after the step h), the underlying layer film using the second intermediate layer pattern as a mask, thereby forming an underlying layer pattern including the first and second patterns,

wherein the underlying layer film is formed of an organic material having a resistance against oxygen-based plasma,

in the step e), the first resist pattern is removed by ashing with oxygen-based plasma, and

the underlying layer film is formed of an organic material to which inorganic nano particles are added.

9. The pattern formation method of claim 8 , wherein 5 to 20 wt % of the inorganic nano particles are added to the underlying layer film.

10. The pattern formation method of claim 8 , wherein the inorganic nano particles are SiO 2 or HfO 2 nano particles.

11. The pattern formation method of claim 8 , wherein exposure in the step c) or the step f) is performed using KrF excimer laser light, Xe 2 laser light, ArF excimer laser light, F 2 laser light, KrAr laser light or Ar 2 laser light.

12. A pattern formation method comprising the steps of:

a) forming an underlying layer film on a substrate;

b) forming an intermediate layer film on the underlying layer film;

c) forming a first resist film on the intermediate layer film and then performing exposure and development to the first resist film through a first photomask having a first pattern, thereby forming a first resist pattern;

d) etching the intermediate film using the first resist pattern as a mask, thereby forming a first intermediate layer pattern;

e) removing the first resist pattern;

f) forming, after the step e), a second resist film on the underlying layer film and the first intermediate layer pattern, and then performing exposure and development to the second resist film through a second photomask having a second pattern, thereby forming a second resist pattern;

g) etching the first intermediate layer pattern using the second resist pattern as a mask, thereby forming a second intermediate layer pattern;

h) removing the second resist pattern; and

i) etching, after the step h), the underlying layer film using the second intermediate layer pattern as a mask, thereby forming an underlying layer pattern including the first and second patterns,

wherein the underlying layer film is formed of an organic material having a resistance against oxygen-based plasma,

in the step e), the first resist pattern s removed by ashing with oxygen-based plasma,

in at least one of the step c) and the step f), immersion exposure is performed with a liquid provided on the first resist film or the second resist film.

13. The pattern formation method of claim 12 , further comprising, before performing the immersion exposure, the step of forming a barrier film on the first resist film or the second resist film.

14. The pattern formation method of claim 13 , further comprising, after forming the barrier film, the step of heating the barrier film.

15. The pattern formation method of claim 13 , wherein polymer forming the barrier film is polyvinyl alcohol, polyacrylic acid or polyvinyl hexafluoroisopropyl alcohol.

16. The pattern formation method of claim 12 , wherein the liquid is water or an acid solution.

17. The pattern formation method of claim 16 , wherein the acid solution is a cesium sulfate aqueous solution or a phosphate aqueous solution.

18. The pattern formation method of claim 12 , wherein exposure in the step c) or the step f) is performed using KrF excimer laser light, Xe 2 laser light, ArF excimer laser light, F 2 laser light, KrAr laser light or Ar 2 laser light.