Metal-compound-removing solvent and method in lithography
View Patent ↗A photoresist layer is coated over a wafer. The photoresist layer includes a metal-containing material. An extreme ultraviolet (EUV) lithography process is performed to the photoresist layer to form a patterned photoresist. The wafer is cleaned with a cleaning fluid to remove the metal-containing material. The cleaning fluid includes a solvent having Hansen solubility parameters of delta D in a range between 13 and 25, delta P in a range between 3 and 25, and delta H in a range between 4 and 30. The solvent contains an acid with an acid dissociation constant less than 4 or a base with an acid dissociation constant greater than 9.
1. A method of fabricating a semiconductor device, comprising:
coating a photoresist layer over a wafer, wherein a first portion of the photoresist layer includes a metal-containing material;
after the coating of the photoresist layer over the wafer, cleaning the wafer with a cleaning fluid to remove the metal-containing material from the first portion of the photoresist layer;
during the cleaning of the wafer with the cleaning fluid, delivering a purging gas to the first portion of the photoresist layer, wherein the cleaning fluid and the purging gas are different from each other; and
after the cleaning of the wafer, performing a lithography exposure process to the photoresist layer of the cleaned wafer, wherein the lithography exposure process includes performing an extreme ultraviolet (EUV) lithography exposure process.
2. The method of claim 1 , wherein the cleaning fluid includes a solvent having Hansen solubility parameters of delta D in a range between 13 and 25, delta P in a range between 3 and 25, and delta H in a range between 4 and 30.
3. The method of claim 2 , wherein the solvent is an aqueous solvent.
4. The method of claim 2 , wherein the solvent is an organic solvent.
5. The method of claim 2 , wherein the solvent contains an acid with an acid dissociation constant (pka) between −11 and 4, and wherein the solvent contains a base with an acid dissociation constant (pka) between 9 and 40.
6. The method of claim 2 , wherein the solvent contains a metal chelate.
7. The method of claim 2 , wherein the solvent contains a surfactant.
8. The method of claim 1 , further comprising: before the coating of the photoresist layer, applying a solvent including a high-contact-angle material to the wafer, wherein the applying of the solvent makes a surface of the wafer hydrophobic.
9. The method of claim 8 , wherein the high-contact-angle material includes carbon fluoride.
10. The method of claim 1 , wherein the cleaning the wafer comprises spinning the wafer as the wafer is being cleaned.
11. The method of claim 1 , wherein the cleaning the wafer comprises applying the cleaning fluid to at least one of: a back side of the wafer or a side edge of the wafer.
12. The method of claim 1 , wherein the purging gas is delivered to at least one of: a back side of the wafer or a side edge of the wafer.
13. The method of claim 1 , further comprising:
performing a pre-exposure baking process, a post-exposure baking process, and a developing process to form a patterned photoresist, wherein the cleaning the wafer is performed after the pre-exposure baking process.
14. A method of fabricating a semiconductor device, comprising:
coating a photoresist layer over a wafer, wherein the photoresist layer includes a metal-containing material;
before the coating of the photoresist layer, applying a high-contact-angle material to the wafer, wherein the applying of the high-contact-angle material makes a surface of the wafer hydrophobic;
performing an extreme ultraviolet (EUV) lithography exposure process; and
after the coating of the photoresist layer, cleaning the wafer with a cleaning fluid to remove the metal-containing material prior to performing the EUV lithography exposure process to the photoresist layer of the cleaned wafer;
wherein:
the cleaning fluid includes a solvent having Hansen solubility parameters of delta D in a range between 13 and 25, delta P in a range between 3 and 25, and delta H in a range between 4 and 30; and
the solvent contains an acid with an acid dissociation constant less than 4 or a base with an acid dissociation constant greater than 9.
15. The method of claim 14 , wherein the cleaning of the wafer with the cleaning fluid to remove the metal-containing material comprises applying the cleaning fluid to at least one of: a back side of the wafer or a side edge of the wafer.
16. The method of claim 14 , wherein the solvent contains a metal chelate.
17. A method comprising:
receiving a wafer;
forming a photoresist material on a surface of the wafer, wherein the photoresist material includes a metal component;
performing a photolithographic exposure of the photoresist material; and
performing a cleaning process on the wafer to remove a portion of the metal component, wherein the cleaning process includes applying a cleaning solution that includes a polar solvent to a portion of the wafer selected from the group consisting of: a back side portion of the wafer and a side edge portion of the wafer, wherein the cleaning process occurs during the forming of the photoresist material on the surface of the wafer.
18. The method of claim 17 , wherein the cleaning solution further includes an ingredient from a group consisting of: an organic acid, an organic base, and a metal chelate.
19. The method of claim 17 , wherein the cleaning process further includes applying a purge gas to the selected portion of the wafer during the applying of the cleaning solution to the selected portion of the wafer.
20. The method of claim 19 , wherein the cleaning process further includes applying negative atmospheric pressure to exhaust air surrounding the wafer.