USE OF A CHEMICAL MECHANICAL POLISHING (CMP) COMPOSITION FOR POLISHING OF COBALT COMPRISING SUBSTRATES

Abstract

A chemical mechanical polishing composition may be used for chemical mechanical polishing of a substrate including (i) cobalt and/or (ii) a cobalt alloy and (iii) TiN and/or TaN, wherein the CMP composition includes (A) inorganic particles (B) at least one organic compound including an amino-group and an acid group, the compound including n amino groups and at least n+1 acidic protons, a being a integer ≥1; (C) at least one oxidizer in an amount of from 0.2 to 2.5 wt.-% based on the total weight of the MP composition; and (D) an aqueous medium. The CMP composition may have a pH of more than 6 and less than 9.

Claims

1. A chemical mechanical polishing (CMP) composition suitable for chemical mechanical polishing of a substrate comprising (i) cobalt and (ii) TiN and/or TaN, the CMP composition comprising: (A) inorganic particles; (B) an organic compound comprising an amino group and an acid group, the organic compound comprising n amino groups and at least n+1 acidic protons, n being an integer >1; (C) an oxidizer in an amount of from 0.2 to 2.5 wt.-%, based on total CMP composition weight; (D) an aqueous medium, wherein the CMP composition (Q) has a pH of more than 6 and less than 9.

2. The composition of claim 1, wherein the inorganic panicles (A) are colloidal inorganic particles.

3. The composition of claim 2, wherein the colloidal inorganic particles are colloidal silica particles.

4. The composition of claim 1, wherein the organic compound is a non-polymeric compound with a molecular weight below 600 g/mol.

5. The composition of claim 1, wherein die acid group in the organic compound (B) comprises a carboxylic acid, sulfonic acid, and/or phosphonic acid.

6. The composition of claim 1, wherein the organic compound (B) comprises an amino acid, substituted ethylenediamine, substituted diethylenetriamine, secondary amine and/or tertiary amine.

7. The composition of claim 1, wherein a total amount of the at least one organic compound (B) is in a range of from 0.1 to 2 wt.-%, based on the total CMP composition weight.

8. The composition of claim 1, further comprising: a corrosion inhibitor (E) in a total amount of from 0.001 to 0.1 wt.-%. based on the total CMP composition weight.

9. The composition of claim 1, wherein the corrosion inhibitor (E) has a pka-value of below 8.

10. The composition of claim 1, further comprising: a surfactant (F) in a total amount of from 0.001 to 0.05 wt.-%, based on the total CMP composition weight.

11. The composition of claim 1, wherein the surfactant (F) is an amphiphilic non-ionic surfactant comprising a polyoxyalkylene group.

12. The composition of claim 1, wherein the oxidizer is hydrogen peroxide.

13. A chemical mechanical polishing (CMP) composition, comprising, based on total CMP composition weight: (A) colloidal silica particles in a total amount of from 0.01 to 2 wt.-%; (B) an organic compound (B) selected from the group consisting of glutamic acid, aspartic acid, ethylenediaminetetraacetic acid, diethylene triamine pentaacetic acid, cysteic acid, ammotris(methylenephosphonic acid), diethylenetriamine penta(methylene phosphonic acid), iminodiacetic acid, and ethylenediamine tetra(methyiene phosphonic acid) in a total amount of from 0.1 to 2 wt.-%; (C) hydrogen peroxide in a total amount of from 0.2 to 1.8 wt.-%; (D) an aqueous medium; (E) a corrosion inhibitor (E) selected from the group consisting of imidazole, benzimidazole, 4-(dimethylamino) benzoic acid, terephthalic acid, isophthalic acid, 6,6′6″-(1,3,5-trizine-2,4,6-triyltriimino)trihexanoic acid, phenyltetrazole, N-lauroylsarcosine, 4-dodecylbenzene sulfonic acid, and phosphoric acid C6 -C10 alkyl ester in a total amount of from 0.002 wt.-% to 0.1 wt.-%; (F) an amphiphilic non-ionic surfactant comprising a polyoxyalkylene group (F) in a total amount of from 0.001 to 0.05 wt.-%; wherein the CMP composition has a pH of more than 6 and less than 9.

14. The composition of claim 1, configured for a process for manufacturing a semiconductor device comprising the chemical mechanical polishing of a substrate (S) used in the semiconductor industry, wherein the substrate (S) comprises (i) cobalt; and (ii) TiN and or TaN.

15. The composition of claim 1, suitable to achieve a static etch rate (SER) of cobalt is below 70 Å/min.

16. The composition of claim 1, suitable for a cobalt material removal rate (MRR) to be adjusted to a range of from 1000 to 4000 Å/min and the TiN material removal rate (MRR) be higher than 300 Å/min.

Description

[0235] The figures show:

[0236] FIG. 1: Schematic illustration of the variation of the shape factor with the shape of a particle

[0237] FIG. 2: Schematic illustration of the variation of the sphericity with the elongation of a particle

[0238] FIG. 3: Schematic illustration of the Equivalent Circle Diameter (ECD)

[0239] FIG. 4: Energy Filtered-Transmission Electron Microscopy (EF-TEM) (120 kilo volts) image of a dried cocoon-shaped silica particle dispersion with 20 wt. % solid content on a carbon foil

[0240] FIG. 5: Correlation diagram of TiN with TaN material removal rates

EXAMPLES AND COMPARATIVE EXAMPLES

[0241] The general procedure for the CMP experiments is described below.

[0242] Standard CMP process for 200 mm Co wafers:

[0243] Tool: Mirra-mesa (Applied Materials) [0244] down pressure: 1.5 psi; [0245] inner tube pressure 2.5 psi; [0246] retaining ring pressure: 4.0 psi; [0247] polishing table/carrier speed: 93/87 rpm; [0248] slurry flow rate: 200 ml/min; [0249] polishing time: 20 s Co  60 s TEOS, TiN [0250] polishing pad: DOW IC 1010; [0251] conditioning tool: 3M A166 diamond abrasive disk for AMAT CMP machines, in-situ conditioning with 5 lbf down force.

[0252] The slurry is stirred in a local supply station.

[0253] Standard analysis procedure for film thickness measurement:

[0254] Cobalt and TiN and TaN film: Resistage RG-120/RT-80, 4 point probe instrument (NAPSON Corporation)

[0255] TEOS: Opti-Probe 2600 (Therma Wave, KLA-Tencor).

[0256] Film thickness is measured pre and post CMP with a 49 point scan (5 mm edge exclusion). The thickness loss is averaged and divided by the polishing time to give the material removal rate (MRR).

[0257] Co coated wafers: 2000 A PVD Co on Ti liner (Supplier: AMT); TiN and TaN: PVD on TEOS

[0258] The pH—value is measured with a pH combination electrode (Schott, blue line 22 pH electrode).

[0259] Standard procedure for determination of Co static etch rates (Co-SER):

[0260] Co-SER experiments were carried out as following:

[0261] 2.5×2.5 cm PVD Co (from AMT) were cut and washed with ultra pure water (UPW). For each coupon the Co film thickness was measured using a 4-point probe instrument at 5 points and averaged out (pre etching, dbefore), 300 ml of freshly prepared slurry with 0.5% H.sub.2O.sub.2 as oxidiser were put into a temperature controlled beaker and stirred. When the slurry has reached 50° C. two Co coupons were put into the slurry and kept in the slurry for 3 min. After the etching has been done the coupons were washed with UPW and dried with N.sub.2. The Co film thickness for each coupon was remeasured using the 4 point probe again at 5 points and averaged out (post etching, defter). The Co-SER was determined by the following formula:

SER(Å/min)=(dbefore−dafter)/3

[0262] For both coupons the SER was averaged to give the final SER value.

[0263] Standard procedure for slurry preparation:

[0264] All mixing procedures are carried out under stirring. An aqueous stock solution of each compound (B), (E) and (F) is prepared by dissolving the desired amount of the respective compound in (D) ultra-pure water (UPW). For the stock solutions of (B) and (E) KOH may be used to support dissolution. The pH of the stock solution is adjusted to 8 by KOH. The stock solutions of (B) have a concentration of the respective additive of 10 wt.-%, that of (E) and (F) of 1.0 wt.-%. For (A) a dispersion is used as provided by the supplier, typically about 20%-30% abrasive concentration by weight. The oxidizer (C) is used as 30 wt.-% stock solution.

[0265] To prepare 1000 g of slurry 600 g of (D) is given into a mixing tank or beaker. The amounts of stock solutions of (B), (E) and (F) are added to reach the desired concentrations. KOH is used to keep the solution at alkaline to neutral pH. Then (A) is added with the necessary amount. To adjust final concentration (D) is added as balance water, with respect to the necessary amount of oxidizer stock solution. The pH is adjusted to the desired value by KOH. The oxidizer is added with the desired amount about 60 min before CMP.

[0266] Inorganic particles (A) used in the Examples

[0267] Colloidal cocoon-shaped Silica particles (A1) having an average primary particle size (d1) of 35 nm and an average secondary particle size (d2) of 70 nm (as determined using dynamic light scattering techniques via a Horiba instrument) (for example Fuso® PL-3) and a specific surface area of around 46 m.sup.2/g were used.

TABLE-US-00001 TABLE 1 Experimental results of particle shape analysis of cocoon-shaped silica particles (A) statistical function ECD shericity shape factor unit nm number of particles 475 475 475 average 53.67 0.631 0.881 minimum 33.68 0.150 0.513 maximum 90.78 0.997 0.978 standard deviation 11.69 0.199 0.083 median d50 51.32 0.662 0.911 d90 0.955

Procedure for Particle Shape Characterization

[0268] An aqueous cocoon-shaped silica particle dispersion with 20 wt. % solid content was dispersed on a carbon foil and was dried. The dried dispersion was analyzed by using Energy Filtered-Transmission Electron Microscopy (EF-TEM) (120 kilo volts) and Scanning Electron Microscopy secondary electron image (SEM-SE) (5 kilo volts). The EF-TEM image with a resolution of 2k, 16 Bit, 0.6851 nm/pixel (FIG. 4) was used for the analysis. The images were binary coded using the threshold after noise suppression. Afterwards the particles were manually separated, Overlying and edge particles were discriminated and not used for the analysis. ECD, shape factor and sphericity as defined before were calculated and statistically classified.

[0269] If present as surfactant (F) an amphiphilic non-ionic polyoxyethylene-polyoxypropylene alkyl ether surfactant is used, which is a mixture of molecules containing, on the average, an alkyl group having 6 to 12 carbon atoms and 2 to 10 oxyethylene monomer units and 1 to 5 oxypropylene monomer units in random distribution (for example Triton™ DF 16 from DOW, Plurafac LF 401 BASF).

TABLE-US-00002 TABLE 2 CMP compositions of the examples 1 to 7 and of the comparative examples (abbreviated as Comp. Ex) 1 to 4, concentration and name of compound (B), Co-MRR, TiN-MRR, TaN-MRR, TEOS-MRR data in the process of chemical-mechanical polishing of 200 mm Co wafers using these compositions, wherein the aqueous medium (D) of the CMP compositions is de- ionized water. For all compositions in this table the pH is 8.5 and the amounts of the other components than (B) of the composition are (A) 1.5 wt.-% colloidal silica, (C) 0.5 wt.-% H.sub.2O.sub.2 (E) 0.03 wt-% Phenyltetratzole and (F) 0.01 wt.-% non-ionic surfactant, specified in weight percent (wt. %) by weight of the corresponding CMP composition. If the amounts of the components other than (D) are in total y % by weight of the CMP composition, then the amount of (D) is (100-y) % by weight of the CMP composition. Concentration of Co TiN TaN TEOS (B) in MRR MRR MRR MRR Example Compound (B) [wt-%] [A/min] [A/min] [A/min] [A/min] Comp. Ex 1 Malonic acid 0.88 219 637 401 19 Comp. Ex 2 Citric acid 1.08 350 670 507 16 Comp. Ex 3 Glycine 0.75 5058 123 56 7 Ex. 1 Glutamic acid 1.24 2835 491 262 14 Ex. 2 DTPA 1.11 2015 613 342 7 Ex. 3 DTPA (*) 1.11 1970 596 349 7 Ex. 4 Cysteic acid 1.58 3760 615 402 20 Ex. 5 Aspartic acid 1.13 2900 537 292 15 Ex. 6 EDTA 0.81 1848 396 200 13 Comp. Ex. 4 — — 103 101 57 1 Ex. 7 Glutamic acid 1.24 3143 568 307 7 Without Compound (E) DTPA: abbreviation for diethylene triamine pentaacetic acid EDTA: abbreviation for ethylene diamine tetra acetate (*) Ex.3 with 0.06 wt.-% of Phenyltetrazole instead of 0.03 wt.-% Phenyltetrazole

[0270] After chemical mechanical polishing the wafers according to the invention showed a shiny surface.

TABLE-US-00003 TABLE 3 Concentration variation series of the oxidizer (C), composition: pH is 8.5, (A) 1.5 wt.-% colloidal silica, (B) 1.24% glutamic acid, (D) de-ionized water, (E) 0.03 wt.-% Isophthalic acid, (F) 0.01 wt.-% non-ionic surfactant, specified in weight percent (wt. %) by weight of the corresponding CMP composition. If the amounts of the components other than (D) are in total y % by weight of the CMP composition, then the amount of (D) is (100 − y) % by weight of the CMP composition. Co-MRR, TiN-MRR, TEOS-MRR data in the process of chemical-mechanical polishing of 200 mm Co wafers using these compositions. Concentration Co TiN of (C) in MRR MRR TEOS MRR Example [wt.-%] [A/min] [A/min] [A/min] Ex. 8 0.00 373 113 24 Ex. 9 0.10 1619 310 25 Ex. 10 0.20 2048 403 25 Ex. 11 0.40 2737 492 21 Ex. 12 0.60 2816 579 22 Ex. 13 0.80 2646 629 23 Ex. 14 1.00 2417 688 22 Ex. 15 1.50 1894 759 27 Ex. 16 2.00 307 814 23 Ex. 17 4.00 158 989 19 Ex. 18 0.25 1962 336 21 Ex. 19 0.50 3100 446 21 Ex. 20 1.00 2352 599 23

[0271] A large influence of the oxidizer (C) concentration can be seen.

TABLE-US-00004 TABLE 4 Variation of component (E) corrosion inhibitor, composition: pH is 8.5, (A) 1.5 wt.-% colloidal silica; (B) 0.81 wt.-% ethylene diamine tetra acetate (EDTA) (C) 0.5 wt.-% H.sub.2O.sub.2 (D) de- ionized water (E) specified in table, (F) 0.01 wt.-% non-ionic surfactant Plurafac LF 401, specified in weight percent (wt. %) by weight of the corresponding CMP composition. If the amounts of the components other than (D) are in total y % by weight of the CMP composition, then the amount of (D) is (100-y) % by weight of the CMP composition, Co-MRR, TiN-MRR, TaN-MRR, TEOS-MRR in the process of chemical-mechanical polishing of 200 mm Co wafers using these compositions and Co-SER data. Component Concentration Co TiN TaN TEOS Co (E) corrosion of (E) MRR MRR MRR MRR SER Example inhibitor [wt.-%] [A/min] [A/min] [A/min] [A/min] [A/min] Ex 21 — — 1886 506 193 11 72 Ex 22 Imidazol 0.03 1990 422 210 9 18.4 Ex 23 Benzimidazol 0.03 1979 435 220 11 21 Ex 24 Korantin SMK 0.005 1857 404 195 10 3.7 Ex 25 DBS 0.005 1898 390 187 9 7.7 Ex 26 Perlastan I 0.005 1968 386 196 13 9.4 Ex 27 4-(Dimethyl 0.03 3818 341 174 4 13.6 amino) benzoic acid Ex 28 Terephthalic 0.03 3624 359 188 8 48.4 acid Ex 29 Isophthalic 0.03 3736 369 192 9 48.3 acid Ex 30 lrgacor L 190 0.03 3774 369 176 6 44.5 Plus Ex 31 Phenyltetrazol 0.03 1848 396 200 13 25.7

Comparative Example 5 (Comp. Ex. 5)

[0272] Composition pH 8.5, (A) 1.5 wt.-% colloidal silica, (B) 1.24 wt.-% glutamic acid (C) 0.5 wt.-% H.sub.2O.sub.2 (D) de-ionized water (E) 0.03 wt.-% Methyl-BTA, (F) 0.01 wt.-% non-ionic surfactant, specified in weight percent (wt. %) by weight of the corresponding CMP composition, If the amounts of the components other than (D) are in total y % by weight of the CMP composition, then the amount of (D) is (100-y) % by weight of the CMP composition. This composition was used to polish Co-wafers. After polishing of 20 PVD Co wafers the polishing pad showed an orange-brown ring on the surface The material that forms the pad residues deposit not only on the pad, but also on the wafer surface causing increased defect rates and yield loss in production.

[0273] The CMP compositions according to the invention are showing an improved polishing performance in terms of high cobalt material removal rates (MRR) [Å/min] combined with increased material removal rates of TIN and TaN and a drastic decrease in the Co etching rates as can be demonstrated by the examples shown in table 2 and table 4 and in the presence of a corrosion inhibitor (E) no residues on the pad (no discoloration) can be detected.