Titanium nitride hard mask and etch residue removal

Patent metadata

Field	Value
Publication number	US-9222018-B1
Application number	US-201514642831-A
Country	US
Kind code	B1
Filing date	Mar 10, 2015
Priority date	Jul 24, 2014
Publication date	Dec 29, 2015
Grant date	Dec 29, 2015

Abstract

Formulations for stripping titanium nitride (TiN or TiNxOy; x=0 to 1.3 and y=0 to 2) hard mask and removing titanium nitride etch residue are low pH (<4) comprise a weakly coordinating anion having negative charge highly dispersed throughout its structure, amine salt buffer, a non-oxidizing trace metal ion, a non-ambient trace oxidizer, and the remaining being solvent selected from the group consisting of water, sulfolane, dimethyl sulfide, lactic acid, glycol, and mixtures thereof. The formulations contain no hydrogen peroxide, and are exposed to air. Bifluoride, corrosion inhibitors, surfactants may be added to the formulations. Systems and processes use the formulations for stripping titanium nitride hard mask and removing titanium nitride etch residue.

First claim

The invention claimed is:

1. A composition for selectively removing titanium nitride (TiN or TiNxOy; where x=0 to 1.3 and y=0 to 2) from a semiconductor device comprising TiN or TiNxOy and a second material selected from the group consisting of Cu, W, low-k dielectric material, and combinations thereof, the composition comprising:
a weakly coordinating anion having negative charge highly dispersed throughout its structure;
an amine salt buffer;
a non-oxidizing trace metal ion;
a non-ambient trace oxidizer; and
the remaining being solvent selected from the group consisting of water, sulfolane, dimethyl sulfide, lactic acid, glycol, and mixtures thereof;
wherein
the composition is hydrogen peroxide-free;
the composition is exposed to air;
the composition has a pH<4; and
the composition offers a removal selectivity of TiN or TiNxOy vs. the second material >1:1.

2. The composition of claim 1 , wherein the weakly coordinating anion is present in a range of 1 to 10 wt % and is selected from the group consisting of: p-toluenesulfonate (C 7 H 8 SO 3 − ), sulfate (SO 4 2− ), nitrate (NO 3 − ), triflate (CF 3 SO 3 − ), fluorosulfate, perfluorosulfonates (R f SO 3 − ; where R f is a perfluoroalkylgroup from C1 to C4), perfluorosulfonimides; ((R f ) 2 NSO 2 − ; where R f is a perfluoroalkylgroup from C1 to C4), hexafluorosilicate (SiF 6 2− ), hexafluorotitanate (TiF 6 2− ), tetrafluoroborate (BF 4 − ), hexafluorophosphate (PF 6 − ), hexafluoroantimonate (SbF 6 − ), perfluoroalkylaluminates ((R f O) 4 Al − , R f is a perfluoroalkyl group), and combinations thereof.

3. The composition of claim 1 , wherein the amine salt buffer is present in a range of 0.5 to 10 wt % and is selected from the group consisting of:
ammonium chloride; ammonium bisulfate; ammonium phosphates; ammonium oxalate;
ammonium perfluorosulfonates; ammonium tetrafluoroborate; ammonium hexafluorotitanate;
ammonium hexafluorosilicate; ammonium salts of organic acid selected from ammonium citrate, ammonium acetate, ammonium lactate; and combinations thereof;
wherein the ammonium having a form of N(R 1 R 2 R 3 R 4 ) + ;
wherein R 1 , R 2 , R 3 , R 4 is independently selected from the group consisting of H, CH 3 , C 2 H 5 and C 3 H 7 .

4. The composition of claim 1 , wherein the non-oxidizing trace metal ion is present at <500 ppm, and is selected from the group consisting of:
Fe(II) ion, Cu(I) ion, Cu(II) ion, Co(II) ion, Cr(II) ion, Mn(II) ion and Ni(II) ion.

5. The composition of claim 1 , wherein the non-ambient trace oxidizer is present in a range of 5-200 ppm, and is selected from the group consisting of Fe(III) compounds, Ce(IV), Vanadium (V), Mn(V, VI or VII) compounds, Cr(V or VI) compounds, CI(I, III or V) compounds, Br(I or III) compounds, and combinations thereof.

6. The composition of claim 1 further comprises <4000 ppm solvolyzing bifluoride selected from the group consisting of ammonium bifluoride, alkylammonium bifluorides aqueous hydrogen fluoride, and combinations thereof.

7. The composition of claim 1 further comprises <10000 ppm corrosion inhibitor selected from the group consisting of benzotriazole and substituted benzotriazole, polyethyleneimine, catechol, cysteine and cystine derivative, glycine, thiourea and thiobiuret, siloxane, aluminum chloride, aluminum fluoride, imidazole, triazole, boric acid, and combinations thereof.

8. The composition of claim 1 , wherein the non-ambient trace oxidizer is non-stoichiometric and the removal selectivity of TiN or TiNxOy vs. the second material is >10:1.

9. The composition of claim 1 , wherein the weakly coordinating anion is hexafluorosilicate, the amine salt buffer is ammonium chloride; the non-oxidizing trace metal ion is Cu(II)Cl 2 ; the non-ambient trace oxidizer is non-stoichiometric Fe(III)Cl 3 , and the removal selectivity of TiN or TiNxOy vs. the second material is >10:1.

10. The composition of claim 9 further comprises ammonium bifluoride and polyethyleneimine.

11. A system for selectively removing titanium nitride (TiN or TiNxOy, where x=0 to 1.3 and y=0 to 2) from a surface of a microelectronic device, comprising:
the semiconductor device comprising TiN or TiNxOy and a second material selected from Cu, W, low-k dielectric material and combinations thereof,
a composition for selectively removing the TiN or TiNxOy from the semiconductor device comprising:
a weakly coordinating anion having negative charge highly dispersed throughout its structure;
an amine salt buffer;
a non-oxidizing trace metal ion;
a non-ambient trace oxidizer; and
the remaining being solvent selected from the group consisting of water, sulfolane, dimethyl sulfide, lactic acid, glycol, and mixtures thereof;
wherein
the composition is hydrogen peroxide-free;
the composition is exposed to air;
the composition has a pH<4; and
the composition offers a removal selectivity of TiN or TiNxOy vs. the second material >1:1;

and
wherein TiN or TiNxOy is in direct contact with the composition and the TiN or TiNxOy is not in direct in contact with W if the second material is W.

12. The system of claim 11 , wherein the weakly coordinating anion is present in a range of 1 to 10 wt % and is selected from the group consisting of:
p-toluenesulfonate (C 7 H 8 SO 3 − ), sulfate (SO 4 2− ), nitrate (NO 3 − ), triflate (CF 3 SO 3 − ), fluorosulfate, perfluorosulfonates (R f SO 3 − ; where R f is a perfluoroalkylgroup from C1 to C4), perfluorosulfonimides; ((R f ) 2 NSO 2 − ; where R f is a perfluoroalkylgroup from C1 to C4), hexafluorosilicate (SiF 6 2− ), hexafluorotitanate (TiF 6 2− ), tetrafluoroborate (BF 4 − ), hexafluorophosphate (PF 6 − ), hexafluoroantimonate (SbF 6 − ), perfluoroalkylaluminates ((R f O) 4 Al − , R f is a perfluoroalkyl group), and combinations thereof.

13. The system of claim 11 , wherein the amine salt buffer is present in a range of 0.5-10 wt % and is selected from the group consisting of:
ammonium chloride; ammonium bisulfate; ammonium phosphates; ammonium oxalate; ammonium perfluorosulfonates; ammonium tetrafluoroborate; ammonium hexafluorotitanate; ammonium hexafluorosilicate; ammonium salts of organic acid selected from ammonium citrate, ammonium acetate, ammonium lactate; and
combinations thereof;
wherein the ammonium having a form of N(R 1 R 2 R 3 R 4 ) + ;
wherein R 1 , R 2 , R 3 , R 4 is independently selected from the group consisting of H, CH 3 , C 2 H 5 , and C3H 7 .

14. The system of claim 11 , wherein the non-oxidizing trace metal ion is in an amount of <500 ppm and is selected from the group consisting of:
Fe(II) ion, Cu(I) ion, Cu(II) ion, Co(II) ion, Cr(II) ion, Mn(II) ion and Ni(II) ion.

15. The system of claim 11 , wherein the non-ambient trace oxidizer is present in a range of 5-200 ppm and is selected from the group consisting of Fe(III) compounds, Ce(IV), Vanadium (V), Mn(V, VI or VII) compounds, Cr(V or VI) compounds, CI(I, III or V) compounds, Br(I or III) compounds, and combinations thereof.

16. The system of claim 11 , wherein the composition further comprises <4000 ppm of solvolyzing bifluoride selected from the group consisting of ammonium bifluoride, alkylammonium bifluoride, aqueous hydrogen fluoride, and combinations thereof.

17. The system of claim 11 , wherein the composition further comprises <10000 ppm of a corrosion inhibitor selected from the group consisting of benzotriazole and substituted benzotriazole, polyethyleneimine, catechol, cysteine and cystine derivative, glycine, thiourea and thiobiuret, siloxane, aluminum chloride, aluminum

Assignees

• Air Prod & Chem

Inventors

• Casteel Jr William Jack
• Inaoka Seiji
• Liu Wen Dar
• Chen Tianniu

Classifications

• H10P50/73

  using masks for insulating materials · CPC title

• H10P70/234

  the processing being the formation of vias or contact holes · CPC title

• H10P50/667

  by liquid etching only · CPC title

• C09K13/08 Primary

  containing a fluorine compound · CPC title

• H01L21/31111

  Electricity · mapped topic