Low pH development solutions for chemically amplified photoresists
View Patent ↗A method for carrying out positive tone lithography with a carbon dioxide development system is carried out by: (a) providing a substrate, the substrate having a polymer resist layer formed thereon, (b) exposing at least one portion of the polymer resist layer to radiant energy causing a chemical shift to take place in the exposed portion and thereby form at least one light field region in the polymer resist layer while concurrently maintaining at least one portion of the polymer layer unexposed to the radiant energy to thereby form at least one dark field region in the polymer resist layer; (c) optionally baking the polymer resist layer; (d) contacting the polymer resist layer to a carbon dioxide solvent system, the solvent system comprising a polar group, under conditions in which the at least one light field region is preferentially removed from the substrate by the carbon dioxide solvent system as compared to the at least one dark field region; wherein the carbon dioxide solvent system comprises a first phase and a second phase, the first phase comprising carbon dioxide and the second phase comprising a polar fluid, with the at least one light field region being preferentially soluble in the polar fluid as compared to the at least one dark field region.
1. A method for carrying out positive tone lithography with a carbon dioxide development system, comprising the steps of:
(a) providing a substrate, the substrate having a polymer resist layer formed thereon,
(b) exposing at least one portion of the polymer resist layer to radiant energy causing a chemical shift to take place in the exposed portion and thereby form at least one light field region in the polymer resist layer while concurrently maintaining at least one portion of the polymer layer unexposed to the radiant energy to thereby form at least one dark field region in said polymer resist layer;
(c) optionally baking the polymer resist layer;
(d) contacting the polymer resist layer to a carbon dioxide solvent system, said solvent system comprising a polar group, under conditions in which said at least one light field region is preferentially removed from said substrate by said carbon dioxide solvent system as compared to said at least one dark field region;
wherein said carbon dioxide solvent system comprises a first phase and a second phase, said first phase comprising carbon dioxide and said second phase comprising a polar fluid, with said at least one light field region being preferentially soluble in said polar fluid as compared to said at least one dark field region;
and wherein said solvent system further comprises a polyol.
2. The method of claim 1 , wherein said polyol is a diol.
3. The method according to claim 1 , wherein said polyol is a diol selected from the group consisting of ethylene glycol, propylene glycol, 1,2 propanediol, 2-methly-1,3-propanediol, neopentyl glycol, 2,2-diethyl-1,3-propanediol, 1,3 butanediol, 1,2-butanediol, 2,3-butanediol, pinacol, 1,2-pentanediol, 2,4-pentanediol 2,4-dimethyl-2,4-pentanediol, 1,2-hexanediol.
4. The method of claim 1 , said carbon dioxide solvent system further comprising a surfactant.
5. The method of claim 1 , said carbon dioxide system containing not more than 20 percent water by weight.
6. The method of claim 1 , wherein said carbon dioxide solvent system is a liquid.
7. The method of claim 1 , wherein said carbon dioxide solvent system comprises a supercritical fluid.
8. The method according to claim 1 , wherein said substrate is a microelectronic substrate.
9. The method according to claim 1 , wherein said radiant energy is deep UV light.
10. The method according to claim 1 , wherein said radiant energy is extreme UV light.
11. A method for carrying out positive tone lithography with a carbon dioxide development system, comprising the steps of:
(a) providing a substrate, the substrate having a polymer resist layer formed thereon,
(b) exposing at least one portion of the polymer resist layer to radiant energy causing a chemical shift to take place in the exposed portion and thereby form at least one light field region in the polymer resist layer while concurrently maintaining at least one portion of the polymer layer unexposed to the radiant energy to thereby form at least one dark field region in the polymer resist layer;
(c) optionally baking the polymer resist layer;
(d) contacting said polymer resist layer to a first carbon dioxide system, wherein said first carbon dioxide system is heterogenous and comprises carbon dioxide, a polyol, and water, under conditions in which the at least one light field region is preferentially removed from said substrate by said first carbon dioxide system as compared to said at least one dark field region, and then
(e) contacting said polymer resist layer to a second carbon dioxide system comprising carbon dioxide and a rinsing agent under conditions in which the said first carbon dioxide system is rinsed away from the substrate without substantial removal of said dark field region.
12. The method of claim 11 , wherein said polyol is a diol.
13. The method of claim 11 , wherein said polyol is a diol selected from the group consisting of ethylene glycol, propylene glycol, 1,2 propanediol, 2-methly-1,3-propanediol, neopentyl glycol, 2,2-diethyl-1,3-propanediol, 1,3 butanediol, 1,2-butanediol, 2,3-butanediol, pinacol, 1,2-pentanediol, 2,4-pentanediol, 2,4-dimethyl-2,4-pentanediol, 1,2-hexanediol.
14. The method of claim 11 , said first carbon dioxide solvent system further comprising a surfactant.
15. The method of claim 11 , said first carbon dioxide system containing not more than 20 percent water by weight.
16. The method of claim 11 , wherein said first carbon dioxide solvent system is a liquid.
17. The method of claim 11 , wherein said first carbon dioxide solvent system comprises a supercritical fluid.
18. The method of claim 11 , wherein said substrate is a microelectronic substrate.
19. The method of claim 11 , wherein said radiant energy is deep UV light.
20. The method of claim 11 , wherein said radiant energy is extreme UV light.