METHOD AND COMPOSITION FOR ETCHING MOLYBDENUM

Abstract

An etchant composition and method for etching molybdenum from a microelectronic device at an etch rate are described. A microelectronic device is contacted with an etchant composition for a time sufficient to at least partially remove the molybdenum. The etchant composition comprises at least one oxidizing agent, at least one oxidizing agent stabilizer, and at least one base and has a pH of from 7.5 to 13. The etchant composition selectively removes molybdenum at an etch rate of 5-200 Å/min.

Claims

1. An etchant composition for removing molybdenum from a microelectronic device, the etchant composition comprising: at least one oxidizing agent; at least one oxidizing agent stabilizer; at least one base; and water, wherein the etchant composition is free of ammonia or ammonium hydroxide and has a pH of from 7.5 to 13.

2. The etchant composition of claim 1, wherein the oxidizing agent comprises a species selected from the group consisting of hydrogen peroxide (H.sub.2O.sub.2), FeCl.sub.3, FeF.sub.3, Fe(NO.sub.3).sub.3, Sr(NO.sub.3).sub.2, CoF.sub.3, MnF.sub.3, oxone, (2KHSO.sub.5.KHSO.sub.4.K.sub.2SO.sub.4), nitric acid (HNO.sub.3), ammonium peroxomonosulfate, ammonium chlorite (NH.sub.4ClO.sub.2), ammonium chlorate (NH.sub.4ClO.sub.3), ammonium iodate (NH.sub.4IO.sub.3), ammonium nitrate (NH.sub.4NO.sub.3), ammonium perborate (NH.sub.4BO.sub.3), ammonium perchlorate (NH.sub.4ClO.sub.4), ammonium periodate (NH.sub.4IO.sub.4), ammonium persulfate ((NH.sub.4).sub.2S.sub.2O.sub.8), ammonium hypochlorite (NH.sub.4ClO), ammonium tungstate ((NH.sub.4).sub.10H.sub.2(W.sub.2O.sub.7)), sodium persulfate (Na.sub.2S.sub.2O.sub.8), sodium hypochlorite (NaClO), sodium perborate, potassium iodate (KIO.sub.3), potassium permanganate (KMnO.sub.4), potassium persulfate (K.sub.2S.sub.2O.sub.8), potassium hypochlorite (KClO), tetramethylammonium chlorite ((N(CH.sub.3).sub.4)ClO.sub.2), tetramethylammonium chlorate ((N(CH.sub.3).sub.4)ClO.sub.3), tetramethylammonium iodate ((N(CH.sub.3).sub.4)IO.sub.3), tetramethylammonium perborate ((N(CH.sub.3).sub.4)BO.sub.3), tetramethylammonium perchlorate ((N(CH.sub.3).sub.4)ClO.sub.4), tetramethylammonium periodate ((N(CH.sub.3).sub.4)IO.sub.4), tetramethylammonium persulfate ((N(CH.sub.3).sub.4)S.sub.2O.sub.8), tetrabutylammonium peroxomonosulfate, peroxomonosulfuric acid, urea hydrogen peroxide ((CO(NH.sub.2).sub.2)H.sub.2O.sub.2), peracetic acid (CH.sub.3(COO)OOH), t-butyl hydroperoxide, nitrobenzensulfonate, 1,4-benzoquinone, toluquinone, dimethyl-1,4-benzoquinone, chloranil, alloxan, periodic acid, and combinations thereof.

3. The etchant composition of claim 1, wherein the at least one oxidizing agent comprises hydrogen peroxide, urea-hydrogen peroxide, ammonium persulfate, periodic acid, peracetic acid, or t-butyl hydroperoxide.

4. The etchant composition of claim 1, wherein the etchant composition comprises from about 0.1 wt % to about 5 wt % of the at least one oxidizing agent.

5. The etchant composition of claim 1, wherein the at least one oxidizing agent stabilizer comprises a species selected from the group consisting of glycine, serine, proline, leucine, alanine, asparagine, aspartic acid, glutamine, valine, and lysine, nitrilotriacetic acid, iminodiacetic acid, etidronic acid, ethylenediaminetetraacetic acid (EDTA), (1,2-cyclohexylenedinitrilo)tetraacetic acid (CDTA), uric acid, tetraglyme, diethylenetriamine pentaacetic acid, propylenediamine tetraacetic acid, ethylendiamine disuccinic acid, sulfanilamide, and combinations thereof.

6. The etchant composition of claim 5, wherein the oxidizing agent stabilizer comprises CDTA or EDTA.

7. The etchant composition of claim 1, wherein the etchant composition comprises from about 0.0001 wt % to about 1.0 wt % of the at least one oxidizing agent stabilizer.

8. The etchant composition of claim 1, wherein the base comprises a species selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAR), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), tributylmethylammonium hydroxide (TBMAH), benzyltrimethylammonium hydroxide (BTMAH), choline hydroxide, ethyltrimethylammonium hydroxide, tris(2-hydroxyethyl)methyl ammonium hydroxide, diethyldimethylammonium hydroxide, tetrabutylphosphonium hydroxide (TBPH), tetramethylphosphonium hydroxide, tetraethylphosphonium hydroxide, tetrapropylphosphonium hydroxide, benzyltriphenylphosphonium hydroxide, methyl triphenylphosphonium hydroxide, ethyl triphenylphosphonium hydroxide, N-propyl triphenylphosphonium hydroxide, and combinations thereof.

9. The etchant composition of claim 1, wherein the base comprises tetramethylammonium hydroxide, choline hydroxide, or combinations thereof.

10. The etchant composition of claim 1, wherein the etchant composition comprises from about 0.1 wt % to about 10 wt % of the base.

11. The etchant composition of claim 1, wherein the etchant composition has a pH between 8 and 11.

12. The etchant composition of claim 1, wherein the etchant composition further comprises at least one complexing agent.

13. The etchant composition of claim 12, wherein the at least one complexing agent comprises a species selected from the group consisting of aminoethylethanolamine, N-methylaminoethanol, aminoethoxyethanol, dimethylaminoethoxyethanol, diethanolamine, N-methyldiethanolamine, monoethanolamine (MEA), triethanolamine (TEA), 1-amino-2-propanol, 2-amino-1-butanol, isobutanolamine, triethylenediamine, 4-(2-hydroxyethyl)morpholine (HEM), ethylenediamine tetraacetic acid (EDTA), m-xylenediamine (MXDA), iminodiacetic acid (IDA), 2-(hydroxyethyl)iminodiacetic acid (HIDA), nitrilotriacetic acid, thiourea, 1,1,3,3-tetramethylurea, urea, urea derivatives, uric acid, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), 1,5,9-triazacyclododecane-N,N′,N″-tris(methylenephosphonic acid) (DOTRP), 1,4,7,10-tetraazacyclododecane-N,N′,N″,N″′-tetrakis(methylenephosphonic acid) (DOTP), nitrilotris(methylene)triphosphonic acid, diethylenetriaminepentakis(methylene phosphonic acid) (DETAP), aminotri(methylene phosphonic acid), bis(hexamethylene)triamine pentamethylene phosphonic acid, 1,4,7-triazacyclononane-N,N′,N″-tris(methylenephosphonic acid (NOTP), hydroxyethyldiphosphonate, nitrilotris(methylene)phosphonic acid, 2-phosphono-butane-1,2,3,4-tetracarboxylic, carboxyethyl phosphonic acid, aminoethyl phosphonic acid, glyphosate, ethylene diamine tetra(methylenephosphonic acid) phenylphosphonic acid, oxalic acid, succinnic acid, maleic acid, malic acid, malonic acid, adipic acid, phthalic acid, citric acid, sodium citrate, potassium citrate, ammonium citrate, tricarballylic acid, trimethylolpropionic acid, tartaric acid, glucuronic acid, 2-carboxypyridine, 4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt, and combinations thereof.

14. The etchant composition of claim 1, wherein the etchant composition further comprises at least one organic solvent.

15. The etchant composition of claim 14, wherein the at least one organic solvent comprises a species selected from the group consisting of wherein the organic additives comprise a species selected from the group consisting of 2-pyrrolidinone, 1-(2-hydroxyethyl)-2-pyrrolidinone (HEP), glycerol, 1,4-butanediol, tetramethylene sulfone, dimethyl sulfone, ethylene glycol, propylene glycol, dipropylene glycol, tetraglyme, diglyme, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether (DEGBE), triethylene glycol monobutyl ether (TEGBE), ethylene glycol monohexyl ether (EGHE), diethylene glycol monohexyl ether (DEGHE), ethylene glycol phenyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether (DPGME), tripropylene glycol methyl ether (TPGME), dipropylene glycol dimethyl ether, dipropylene glycol ethyl ether, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether (DPGPE), tripropylene glycol n-propyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, or propylene glycol phenyl ether, and combinations thereof.

16. The etchant composition of claim 14, wherein the at least one organic solvent is propylene glycol.

17. The etchant composition of claim 1, wherein the etchant composition further comprises at least one metal corrosion inhibitor.

18. The etchant composition of claim 17, wherein the at least one metal corrosion inhibitor comprises a species selected from the group consisting of 5-aminotetrazole, 5-phenyl-benzotriazole, 1H-tetrazole-5-acetic acid, 1-phenyl-2-tetrazoline-5-thione, benzimidazole, methyltetrazole, pyrazoles, 5-amino-1,3,4-thiadiazole-2-thiol (ATDT), benzotriazole (BTA), 1,2,4-triazole (TAZ), 1,2,3-triazole, tolyltriazole, 5-methyl-benzotriazole (mBTA), 5-phenyl-benzotriazole, 5-nitro-benzotriazole, benzotriazole carboxylic acid, 3-amino-5-mercapto-1,2,4-triazole, 1-amino-1,2,4-triazole, hydroxybenzotriazole, 2-(5-amino-pentyl)-benzotriazole, 1-amino-1,2,3-triazole, 1-amino-5-methyl-1,2,3 -triazole, 3-amino-1,2,4-triazole (3-ATA), 3-mercapto-1,2,4-triazole, 3-isopropyl-1,2,4-triazole, 5-phenylthiol-benzotriazole, halo-benzotriazoles (halo=F, Cl, Br or I), naphthotriazole, 2-mercaptobenzimidazole (MBI), 2-mercaptobenzothiazole, 4-methyl-2-phenylimidazole, 2-mercaptothiazoline, 5-amino-1,2,4-triazole (5-ATA), 3-amino-5-mercapto-1,2,4-triazole, pentylenetetrazole, 5-phenyl-1H-tetrazole, 5-benzyl-1H-tetrazole, 2,4-diamino-6-methyl-1,3,5-triazine, thiazole, triazine, methyltetrazole, 1,3-dimethyl-2-imidazolidinone, 1,5-pentamethylenetetrazole, 1-phenyl-5-mercaptotetrazole, diaminomethyltriazine, imidazoline thione, 4-methyl-4H-1,2,4-triazole-3-thiol, 4-amino-4H-1,2,4-triazole, 3-amino-5-methylthio-1H-1,2,4-triazole, benzothiazole, imidazole, indiazole, adenine, adenosine, carbazole, and combinations thereof.

19. The etchant composition of claim 18, wherein the at least one metal corrosion inhibitor is tolyltriazole.

20. A method of removing molybdenum from a microelectronic device the method comprising: i) contacting the microelectronic device with an etchant composition for a time sufficient to at least partially remove the molybdenum from the microelectronic device, the etchant composition comprising: at least one oxidizing agent; at least one oxidizing agent stabilizer; and at least one base and ii) etching molybdenum at an etch rate of 5-200Å/min, wherein the etchant composition is free of ammonia or ammonium hydroxide and has a pH of from 7.5 to 13.

Description

EXAMPLES

[0040] The features and advantages of the etchant compositions of the present disclosure are more fully illustrated by the following non-limiting examples, wherein all parts and percentages are by weight, unless otherwise expressly stated. High pH etchant compositions are shown that are particularly useful for the selective removal of molybdenum from microelectronic devices at an etch rate of 5-200 Å/min.

[0041] The etchant compositions were prepared by combining oxidizer and complexing agent adjusted to the target pH using TEAH as the titrator. The mixture was stirred for 15 min at room temperature to afford a clear solution.

[0042] Coupons having a Mo layer were placed in a bath containing the compositions for 15 min at 30° C. The amount of Mo removed was measured, and TiN etch rates for these compositions were also determined.

[0043] Etchant compositions and their corresponding etch rates are shown in Table 1 below.

TABLE-US-00002 TABLE 1 Oxidizing Complexing Mo Etch rate TiN Etch rate Ex Agent Agent Base pH (Å/min) (Å/min) 1 H.sub.2O.sub.2 None TEAH 9 130 0.01 2 H.sub.2O.sub.2 None TEAH 11 89 0.01 3 urea-H.sub.2O.sub.2 None TEAH 9 10 0.2 4 urea-H.sub.2O.sub.2 None TEAH 11 11 0.1 5 periodic acid None TEAH 9 59 0.1 6 periodic acid None TEAH 11 34 1.8 7 ammonium persulfate None TEAH 9 28 0.18 8 ammonium persulfate None TEAH 11 19 0.32 9 peracetic acid None TEAH 9 40 0.01 10 peracetic acid None TEAH 11 26 0.98 11 t-butyl hydroperoxide None TEAH 9 17 0.34 12 t-butyl hydroperoxide None TEAH 11 15 0.2 13 H.sub.2O.sub.2 citric acid TEAH 9 173 0.01 14 H.sub.2O.sub.2 citric acid TEAH 11 171 0.01 15 H.sub.2O.sub.2 lactic acid TEAH 11 178 0.03 16 H.sub.2O.sub.2 HEDP TEAH 11 152 0.01
Each of these compositions included oxidizing agent at 1 wt % and CDTA as an oxidizing agent stabilizer at 0.01 wt %.

[0044] As shown, each of these etchant compositions, comprising at least one oxidizing agent, at least one oxidizing agent stabilizer, and at least one base to a pH of from 7.5 to 13, preferably 8 to 11, controllably removes molybdenum at an etch rate of 5-200 Å/min. In addition, corresponding TiN etch rates are very low, demonstrating the selectivity of the etchant composition for removing Mo.

[0045] Although the invention has been variously disclosed herein with reference to illustrative embodiments and features, it will be appreciated that the embodiments and features described hereinabove are not intended to limit the invention, and that other variations, modifications and other embodiments will suggest themselves to those of ordinary skill in the art, based on the disclosure herein. The invention therefore is to be broadly construed, as encompassing all such variations, modifications and alternative embodiments within the spirit and scope of the claims hereafter set forth.