Selectively Removing Titanium Nitride Hard Mask and Etch Residue Removal

Patent metadata

Field	Value
Publication number	US-2016293479-A1
Application number	US-201615077374-A
Country	US
Kind code	A1
Filing date	Mar 22, 2016
Priority date	Mar 31, 2015
Publication date	Oct 6, 2016
Grant date	—

Abstract

Formulations for stripping titanium nitride hard mask and removing titanium nitride etch residue comprise an amine salt buffer, a non-ambient oxidizer, and the remaining being liquid carrier includes water and non-water liquid carrier selected from the group consisting of dimethyl sulfone, lactic acid, glycol, and a polar aprotic solvent including but not limited to sulfolanes, sulfoxides, nitriles, formamides and pyrrolidones. The formulations have a pH <4, preferably <3, more preferably <2.5. The aqueous formulations having water as liquid carrier and semi-aqueous formulation having water and non-polar aprotic solvent(s) further contain acidic fluoride. The formulations offer high titanium nitride etch rates while provide excellent compatibility towards W, AlN, AlO, and low k dielectric materials. The formulations may comprise weakly coordinating anions, corrosion inhibitors, and surfactants. Systems and processes use the formulations for stripping titanium nitride hard mask and removing titanium nitride etch residue.

First claim

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 titanium nitride and a second material; the composition comprising:
an amine salt buffer; a non-ambient oxidizer; and liquid carrier; wherein the composition comprises no hydrogen peroxide; the composition has a pH<4; the second material is selected from the group consisting of Cu, W, aluminum nitride (AlNx with x=0.5 to 1), aluminum oxide(AlOx with x=1 to 1.5), low-k dielectric material, and combinations thereof; 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 amine salt buffer is present in the 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 .

3 . The composition of claim 1 , wherein the non-ambient oxidizer is present in the range of 0.2 to 3 wt % and is selected from the group consisting of salt of persulfate selected from the group consisting of sodium persulfate, ammonium persulfate, and combinations thereof; salt of iodate, salt of periodate, Cl(I, III or V) compounds, Br(I, III or V) compounds, and combinations thereof.

4 . The composition of claim 1 , wherein the liquid carrier is water; and the composition further comprises <4000 ppm of an acidic fluoride selected from the group consisting of ammonium bifluoride, alkylammonium bifluoride, aqueous hydrogen fluoride, fluorosilicic acid, fluoroboric acid, acid of hydrated fluoroaluminate, and combinations thereof.

5 . The composition of claim 4 , wherein the amine salt buffer is selected from the group consisting of ammonium chloride, ammonium bisulfate and combinations thereof; the non-ambient oxidizer is selected from the group consisting of ammonium persulfate, sodium persulfate, and combinations thereof; and the acidic fluoride is selected from the group consisting of ammonium bifluoride, hydrofluoric acid, and combinations thereof.

6 . The composition of claim 1 , wherein the composition is a semi-aqueous composition having liquid carrier comprising water and at least one non-water liquid carrier selected from the group consisting of dimethyl sulfone, lactic acid, glycol, a polar aprotic solvent selected from the group consisting of sulfolanes, sulfoxides, nitriles, formamides and pyrrolidones, and combinations thereof; and the composition further comprises <4000ppm of an acidic fluoride selected from the group consisting of ammonium bifluoride, alkylammonium bifluoride, aqueous hydrogen fluoride, fluorosilicic acid, fluoroboric acid, acid of hydrated fluoroaluminate, and combinations thereof.

7 . The composition of claim 6 , wherein the amine salt buffer is selected from the group consisting of ammonium chloride, ammonium bisulfate and combinations thereof; the non-ambient oxidizer is selected from the group consisting of ammonium persulfate, sodium persulfate, and combinations thereof; and the acidic fluoride is selected from the group consisting of ammonium bifluoride, hydrofluoric acid, and combinations thereof.

8 . The composition of claim 1 , wherein the composition is a semi-aqueous composition having liquid carrier consisting of water and a polar aprotic solvent selected from the group consisting of sulfolane, sulfoxide, nitrile, formamide, pyrrolidone, and combinations thereof.

9 . The composition of claim 8 , wherein the amine salt buffer is selected from the group consisting of ammonium chloride, ammonium bisulfate and combinations thereof; and the non-ambient oxidizer is selected from the group consisting of ammonium persulfate, sodium persulfate, and combinations thereof.

10 . The composition of claim 1 further comprises at least one selected from the group consisting of
a weakly coordinating anion is present in the 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 − ), 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((RfO) 4 Al; R f is a perfluoroalkyl group), and combinations thereof; and
a corrosion inhibitor in the range of <2000 ppm selected from the group consisting of benzotriazole or substituated benzotriazole, polyethyleneimine, catechol, cysteine and cystine derivative, glycine, thiourea and thiobiuret, siloxane, aluminum chloride, aluminum fluoride, imidazole, triazole, boric acid, and combinations thereof.

11 . The composition of claim 1 , wherein the pH of the composition is <3; the composition offers a removal selectivity of TiN or TiNxOy vs. the second material >5:1.

12 . 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, a composition for selectively removing the TiN or TiNxOy from the semiconductor device comprising: 0.5 to10 wt % of amine salt buffer 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 ) + ; and 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 ;
0.2 to 3 wt % non-ambient oxidizer selected from the group consisting of salts of persulfates, salts of iodate, salts of periodate, Cl(I,III or V) compounds, Br(I, III or V) compounds, and combinations thereof; and liquid carrier; wherein the composition comprises no hydrogen peroxide; the composition has a pH<4; the second material is selected from the group consisting of Cu, W, aluminum nitride (AlNx with x=0.5 to 1), aluminum oxide(AlOx with x=1 to 1.5), low-k dielectric material, and combinations thereof; and the composition offers a removal selectivity of TiN or TiNxOy vs. the second material >1:1.

13 . The system of claim 12 , wherein the liquid carrier in the composition is water;
and the composition further comprises <4000ppm of an acidic fluoride selected from the group consisting of ammonium bifluoride, alkylammonium bifluoride, aqueous hydrogen fluoride, fluorosilicic acid, fluoroboric acid, acid of hydrated fluoroaluminate, and combinations thereof.

14 . The system of claim 14 , wherein the amine salt buffer is selected from the group consisting of ammonium chloride, ammonium bisulfate and combinations thereof; the non-ambient oxidizer is selected from the group consisting of ammonium persulfate, sodium persulfate, and combinations thereof; and the acidic fluor

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

• H10P50/667 Primary

  by liquid etching only · CPC title

• H10W20/081 Primary

  by forming openings in the dielectric parts · CPC title

• H10P50/283

  by chemical means · CPC title

• H01L21/76814 Primary

  Electricity · mapped topic