Gap filling composition and pattern forming method using low molecular weight compound

1. A method of forming a pattern, comprising:

(i) the step of etching a substrate to form a gap;

(ii) the step of filling a gap filling composition comprising a low molecular weight compound having 2 to 25 carbon atoms into the substrate surface comprising a gap formed thereon; and

(iii) the step of removing the composition by heating, reduced pressure, air-drying, or a combination thereof and

wherein at the end of the step (i), the substrate surface is contacted to a liquid and then the gap is filled with the liquid,

in the step (ii) the liquid is replaced by the gap filling composition;

wherein the low molecular weight compound having 2 to 25 carbon atoms is a gap filling compound represented by following general formula (Ia) or formula (Ib)

wherein each R a independently represents hydrogen, alkyl having 1 to 5 carbon atoms, or aryl having 6 to 12 carbon atoms,

each L a independently represents, alkylene having 1 to 10 carbon atoms, haloalkylene having 1 to 10 carbon atoms, heteroalkylene having 1 to 10 carbon atoms comprising oxy, imino, or sulfide on a terminal or between carbons thereof, oxy, imino, sulfide, or a single bond,

each Y a independently represents —OH, —COOH, or —NR 1 2,

each R 1 independently represents hydrogen or alkyl having 1 to 5 carbon atoms, and

p represents an integer of 1 to 8, or

[Y b q Z b R b ] r   formula (Ib)

wherein each R b independently represents alkyl having 1 to 5 carbon atoms, or aryl having 6 to 12 carbon atoms,

Z b represents cycloalkyl having 3 to 13 ring members, heterocycloalkyl having 3 to 13 ring members comprising O, N, or S, or aryl having 6 to 20 carbon atoms,

each Y b independently represents —OH, —COOH, or —NR 2 2 ,

each R 2 independently represents hydrogen or alkyl having 1 to 5 carbon atoms, and

q represents an integer of 2 to 5, and

r represents a maximum number of substituents of the cycloalkyl, the heterocycloalkyl, or the aryl in Zb-q;

the gap filling composition comprises: the gap filling compound; an organic solvent; and water, and

the mass ratios of the gap filling compound, the organic solvent, and water to the total mass of the gap filling composition are not less than 1% and not more than 100%, not less than 5% and not more than 99%, not less than 0% and not more than 30%, respectively.

2. The method according to claim 1 , wherein the mass ratios of the gap filling compound and the organic solvent to the total mass of the gap filling composition are not less than 2% and not more than 40%, and not less than 20% and not more than 98%, respectively.

3. The method according to claim 1 , wherein the composition further comprises a surfactant.

4. The method according to claim 1 , wherein the organic solvent is selected from the group consisting of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, isopropyl alcohol, n-butyl alcohol, methyl isobutyl ketone, tetrahydrofuran, dibutyl ether, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, 2-heptanone, γ-butyrolactone, and any combination of any thereof.

5. The method according to claim 1 , wherein a vapor pressure of the gap filling compound at 150° C. and 1 atm is not less than 100 Pa and not more than 40,000 Pa.

6. The method according to claim 1 , wherein the low molecular weight compound is a compound represented by the following general formula (Ia)

7. The method according to claim 1 , comprising forming, by dry etching and/or wet etching, a mask for etching the substrate.

8. The method according to claim 1 , wherein the step (iii) is carried out by heating at not less than 50° C. and not more than 500° C. for not less than 30 seconds and not more than 300 seconds.

9. The method according to claim 1 , wherein in the step (i) an etching amount in a depth direction of the substrate is not less than 0.05 μm and not more than 6.00 μm.

10. The method according to claim 1 , wherein an aspect ratio of the pattern is not less than 5 and not more than 25.

11. The method according to claim 1 , wherein the gap filling compound of the formula (Ia) or formula (Ib) has a molecular weight up to 250.

12. The method according to claim 1 , wherein the gap filling compound of the formula (Ia) or formula (Ib) has a molecular weight up to 150.

13. The method according to claim 1 , wherein the gap filling compound of the formula (Ia) or formula (Ib) has 2 to 10 carbon atoms.

14. The method according to claim 1 , wherein the gap filling compound of the formula (Ia) or formula (Ib) has 2 to 10 carbon atoms.

15. The method as claimed in claim 1 , wherein the mass ratio of water to the total mass of the gap filling composition is less than that of the organic solvent.

16. The method as claimed in claim 1 , wherein the gap filling compound consists essentially of the compound of the general formula (Ia) or formula (Ib).

17. The method according to claim 16 , wherein the gap filling compound of the formula (Ia) or formula (Ib) has a molecular weight up to 250.

18. The method as claimed in claim 1 , wherein the gap filling compound consists of the compound of the general formula (Ia) or formula (Ib).

19. The method as claimed in claim 1 , wherein the gap filling composition consists essentially of the gap filling compound; an organic solvent; and water.