Stripper solutions effective for back-end-of-line operations
Back end of line (BEOL) stripping solutions which can be used in a stripping process that replaces etching resist ashing process are provided. The stripping solutions are useful for fabricating circuits and/or forming electrodes on semiconductor devices for semiconductor integrated circuits with good efficiency and with low and acceptable metal etch rates. Methods for their use are similarly provided. The preferred stripping agents contain a polar aprotic solvent, water, an amine and a quaternary hydroxide that is not tetramethylammonium hydroxide. Further provided are integrated circuit devices and electronic interconnect structures prepared according to these methods.
1. A stripper solution for removing a resist from a substrate comprising a polar aprotic solvent, water, an amine, and a quaternary hydroxide, wherein the quaternary hydroxide has the formula:
wherein Z is N or P and R 1 , R 2 , R 3 , and R 4 are alkyl groups, benzyl, aryl groups, or a combination thereof wherein the combination collectively has at least 5 carbons; and wherein water is present in an amount ranging from greater than 8 wt. % to 15 wt. % based on the weight of the solution.
2. The stripper solution of claim 1 , wherein the stripper solution additionally contains glycerine and the polar aprotic solvent is selected from the group consisting of dimethyl sulfoxide and 1-formylpiperidine.
3. The stripper solution of claim 1 , wherein the aprotic solvent comprises from about 40% to about 90% of the solution; the quaternary hydroxide comprises from about 2% to about 10% of the solution; and the amine comprises from about 2% to about 60% of the solution.
4. The stripper solution of claim 3 , wherein the aprotic solvent is dimethyl sulfoxide.
5. The stripper solution of claim 3 wherein said amine is an alkanolamine having at least two carbon atoms, at least one amino substituent and at least one hydroxyl substituent, the amino and hydroxyl substituents attached to different carbon atoms.
6. The stripper solution of claim 3 wherein Z is P and the quaternary hydroxide is selected from the group consisting of tetrabutyl phosphonium hydroxide, tetraphenyl phosphonium hydroxide, methyl triphenyl phosphonium hydroxide, ethyl triphenyl phosphonium hydroxide, propyl triphenyl phosphonium hydroxide, butyl triphenyl phosphonium hydroxide, benzyl triphenyl phosphonium hydroxide, allyl triphenyl phosphonium hydroxide, dodecyl triphenyl phosphonium hydroxide, tetradecyl triphenyl phosphonium hydroxide, hexadecyl triphenyl phosphonium hydroxide, hexadecyl tributyl phosphonium hydroxide, carbethoxyethyl triphenyl phosphonium hydroxide, carbmethoxyethyl triphenyl phosphonium hydroxide, carbethoxymethyl triphenyl phosphonium hydroxide, and carbmethoxymethyl triphenyl phosphonium hydroxide.
7. A method for removing a resist from a substrate comprising: (a) providing a substrate having a resist thereon; (b) contacting the substrate with a stripper solution for a time sufficient to remove the resist; (c) removing the substrate from the stripping solution; and (d) rinsing the stripper solution from the substrate with a solvent, wherein the step of contacting the substrate with a stripper solution involves contacting the substrate with a stripper solution including a polar aprotic solvent, water, an amine, and a quaternary hydroxide having the formula:
where Z is N or P and R 1 , R 2 , R 3 , and R 4 are alkyl groups, benzyl, aryl groups, or a combination thereof wherein the combination collectively has at least 5 carbons; and wherein water is present in an amount ranging from greater than 8 wt. % to 15 wt. % based on the weight of the solution.
8. The method of claim 7 , wherein contacting the substrate with a stripper solution includes contacting the substrate with a stripper solution including a polar aprotic solvent comprising from about 40% to about 90% of the solution; water comprising from about 10% to about 15% of the solution; the quaternary hydroxide comprising from about 2% to about 10% of the solution; and the amine comprising from about 2% to about 60% of the solution.
9. The method of claim 7 , wherein contacting the substrate with a stripper solution includes contacting the substrate with a stripper solution, wherein the polar aprotic solvent is dimethyl sulfoxide.
10. The method of claim 9 , wherein contacting the substrate with a stripper solution includes contacting the substrate with a stripper solution, wherein the polar aprotic solvent further comprises 1-formylpiperidine.
11. The method of claim 7 , wherein contacting the substrate with a stripper solution includes contacting the substrate with a stripper solution including an amine which comprises an alkanolamine having at least two carbon atoms, at least one amino substituent and at least one hydroxyl substituent, the amino and hydroxyl substituents attached to different carbon atoms.
12. The method of claim 11 , wherein contacting the substrate with a stripper solution includes contacting the substrate with a stripper solution having quaternary hydroxide selected from the group consisting of tetrabutyl phosphonium hydroxide, tetraphenyl phosphonium hydroxide, methyl triphenyl phosphonium hydroxide, ethyl triphenyl phosphonium hydroxide, propyl triphenyl phosphonium hydroxide, butyl triphenyl phosphonium hydroxide, benzyl triphenyl phosphonium hydroxide, allyl triphenyl phosphonium hydroxide, dodecyl triphenyl phosphonium hydroxide, tetradecyl triphenyl phosphonium hydroxide, hexadecyl triphenyl phosphonium hydroxide, hexadecyl tributyl phosphonium hydroxide, carbethoxyethyl triphenyl phosphonium hydroxide, carbmethoxyethyl triphenyl phosphonium hydroxide, carbethoxymethyl triphenyl phosphonium hydroxide, and carbmethoxymethyl triphenyl phosphonium hydroxide.
13. The method of claim 7 , wherein contacting the substrate with a stripper solution includes immersing the substrate in the stripping solution with agitation at a temperature of at least about 40° C.
14. The method of claim 7 , wherein contacting the substrate with a stripper solution includes spraying the stripper solution onto the substrate, wherein the stripper solution is at a temperature of at least about 40° C.
15. The method of claim 7 , wherein providing a substrate having a resist thereon, involves providing a substrate having a resist which is a bilayer resist having two polymer layers.
16. The method of claim 7 , wherein providing a substrate having a resist thereon, involves providing a substrate having a resist which is a bilayer resist having one inorganic layer and one polymer layer.
17. The method of claim 7 , further comprising the step of removing adsorbed volatiles from the substrate to obtain a processed substrate, wherein providing a substrate includes providing a substrate having a low-κ permittivity value identified as κ a and obtaining a processed substrate includes obtaining a processed substrate having a low-κ permittivity value identified as κ c ,
wherein, Δκ is defined as the difference between κ c and κ a , and
wherein Δκ≦0.1.
18. An electronic device prepared according to the method comprising: (a) providing a substrate having a resist thereon; (b) contacting the substrate with a stripper solution for a time sufficient to remove a desired amount of resist; (c) removing the substrate from the stripping solution; and (d) rinsing the stripper solution from the substrate with a solvent, wherein contacting the substrate with a stripper solution involves contacting the substrate with a stripper solution including a polar aprotic solvent, water, an amine, and a quaternary hydroxide having the formula:
where Z is N or P and R 1 , R 2 , R 3 , and R 4 are alkyl groups, benzyl, aryl groups, or a combination thereof wherein the combination collectively has at least 5 carbons; and wherein water is present in an amount ranging from greater than 8 wt. % to 15 wt. % based on the weight of the solution.
19. A method for preparing a BEOL stripper solution comprising the acts of: (a) providing a container; (b) providing components of the stripper solution formulation; and (c) adding said components of said stripper solution to said container to provide contents, wherein said providing components involves providing a polar aprotic organic solvent, water, an amine, and a quaternary hydroxide, the quaternary hydroxide having the formula:
where Z is N or P and R 1 , R 2 , R 3 , and R 4 are alkyl groups, benzyl, aryl groups, or a combination thereof wherein the combination collectively has at least 5 carbons; and wherein water is present in an amount ranging from greater than 8 wt. % to 15 wt. % based on the weight of the solution.