Ionic thermal acid generators for low temperature applications
View Patent ↗New ionic thermal acid generator compounds are provided. Also provided are photoresist compositions, antireflective coating compositions, and chemical trim overcoat compositions, and methods of using the compositions.
1. A method for providing a photoresist relief image, comprising:
a) applying a coating layer of a chemically amplified photoresist composition on a substrate;
b) exposing the photoresist layer to activating radiation and developing the exposed photoresist layer to provide a photoresist relief image;
c) applying over the exposed photoresist composition coating layer a coating layer of a chemical trim overcoat composition comprising a thermal acid generator of formula (I);
(A − )(BH) + (I)
in which
A − is the anion of an organic or inorganic acid having a pKa of not more than 3; and
(BH) + is the monoprotonated form of a nitrogen-containing base B having a pKa between 0 and 5.0, and a boiling point less than 170° C.;
d) heating the chemical trim overcoat composition layer; and
e) developing the photoresist layer to provide a photoresist relief image.
2. The method of claim 1 wherein B is selected from the group consisting of:
in which Y is methyl or ethyl.
3. The method of claim 1 wherein B is substituted pyridine.
4. The method of claim 1 wherein A − is the anion of a fluoroalkylsulfonic acid.
5. The method of claim 1 wherein the thermal acid generator is selected from among:
3-Fluoropyridinium perfluorobutanesulfonate;
3-Fluoropyridinium triflate; and
3-Fluoropyridinium p-toluenesulfonate.
6. A coated substrate comprising:
a photoresist layer; and
over the photoresist layer, a chemical trim overcoat layer comprising an ionic thermal acid generator of formula (I)
(A − )(BH) + (I)
in which
A − is the anion of an organic or inorganic acid having a pKa of not more than 3; and
(BH) + is the monoprotonated form of a nitrogen-containing base B having a pKa between 0 and 5.0, and a boiling point less than 170° C.
7. The substrate of claim 6 wherein B is selected from the group consisting of:
in which Y is methyl or ethyl.
8. The substrate of claim 6 wherein B is substituted pyridine.
9. The substrate of claim 6 wherein A − is the anion of a fluoroalkylsulfonic acid.
10. The substrate of claim 6 wherein the thermal acid generator is selected from among:
3-Fluoropyridinium perfluorobutanesulfonate;
3-Fluoropyridinium triflate; and
3-Fluoropyridinium p-toluenesulfonate.
11. A coated substrate comprising: an antireflective composition layer comprising a thermal acid generator of formula (I):
(A) − (BH) + (I)
in which A − is the anion of an organic or inorganic acid having a pKa of not more than 3; and (BH) + is the monoprotonated form of a nitrogen-containing base B having a pKa between 0 and 5.0, and a boiling point less than 170° C.;
and over the antireflective coating composition layer, a photoresist composition layer, wherein B is selected from the group consisting of:
and substituted pyridine,
in which Y is methyl or ethyl.
12. The substrate of claim 11 wherein B is substituted pyridine.
13. The substrate of claim 11 wherein A − is the anion of a fluoroalkylsulfonic acid.
14. The substrate of claim 11 wherein the thermal acid generator is selected from among:
3-Fluoropyridinium perfluorobutanesulfonate;
3-Fluoropyridinium triflate; and
3-Fluoropyridinium p-toluenesulfonate.
15. A thermal acid generator represented by the formula:
(A − )(BH) +
in which
A − is the anion of a fluoroalkylsulfonic acid or inorganic acid having a pKa of not more than 3; and
(BH) + is the monoprotonated form of a nitrogen-containing base B having a pKa between 0 and 5.0, and a boiling point less than 170° C., and
wherein B is selected from the group consisting of:
in which Y is methyl or ethyl.
16. The thermal acid generator of claim 15 , wherein A − is the anion of a fluoroalkylsulfonic acid.