USE OF A CHEMICAL MECHANICAL POLISHING (CMP) COMPOSITION FOR POLISHING OF COBALT AND / OR COBALT ALLOY COMPRISING SUBSTRATES

Abstract

Use of a chemical mechanical polishing (CMP) composition (Q) for chemical mechanical polishing of a substrate (S) comprising (i) cobalt and/or (ii) a cobalt alloy, wherein the CMP composition (Q) comprises (A) Inorganic particles (B) a triazine derivative of the general formula (I) wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are independently from each other H, methyl, ethyl, propyl, butyl, pentyl, C.sub.2-C.sub.10-alkylcarboxylic acid, hydroxymethyl, vinyl or allyl (C) at least one amino acid, (D) at least one oxidizer (E) an aqueous medium and wherein the CMP composition (Q) has a pH of from 7 to 10.

##STR00001##

Claims

1. A method for chemical mechanical polishing (CMP) a substrate comprising (i) cobalt and/or (ii) a cobalt alloy, the method comprising polishing the substrate with a CMP composition comprising: (A) inorganic particles (B) a triazine derivative of the general formula (I) ##STR00004## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are independently from each other H, methyl, ethyl, propyl, butyl, pentyl, C.sub.2-C.sub.10-alkylcarboxylic acid, hydroxymethyl, vinyl or allyl, (C) at least one amino acid, (D) at least one oxidizer, and (E) an aqueous medium wherein the CMP composition has a pH of from 7 to 10.

2. The method according to claim 1, wherein the inorganic particles (A) are colloidal inorganic particles.

3. The method according to claim 2, wherein the colloidal inorganic particles are silica particles.

4. The method according to claim 1, wherein the compound (B) is of general formula (I) and wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are independently from each other H, methyl, ethyl, propyl, butyl, C.sub.2-C.sub.10-alkylcarboxylic acid, hydroxymethyl or allyl.

5. The method according to claim 1, wherein the compound (B) is of general formula (I) and wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are independently from each other H, methyl, tert-butyl, hexanoic acid, hydroxymethyl or allyl.

6. The method according to claim 1, wherein the total amount of compound (B) of general formula (I) is in the range of from 0.003 wt.-% to 0.1 wt.-% based on the total weight of the CMP composition.

7. The method according to claim 1, wherein the at least one amino acid (C) is glycine, alanine, leucine, valine, cysteine, serine, proline or a salt thereof.

8. The method according to claim 1, wherein the total amount of the at least one amino acid (C) is in the range of from 0.1 wt.-% to 2.25 wt.-% based on the total weight of the CMP composition.

9. The method according to claim 1, wherein the oxidizer comprises a peroxide.

10. The method according to claim 1, wherein the oxidizer is hydrogen peroxide.

11. A chemical mechanical polishing (CMP) composition comprising: (A) colloidal silica particles in a total amount of from 0.01 wt.-% to 3 wt.-% based on the total weight of the CMP composition, (B) at least one triazine derivative (B) selected from the group consisting of melamine, 6,6′,6″-(1,3,5-Triazine-2,4,6-triyltriimino)trihexanoic acid, 2,4,6-trimethylmelamine, Pentamethylmelamine, {[bis(dimethylamino)-1,3,5-triazin-2-yl)]methyl)amino}-methanol, ({bis[(hydroxymethyl)amino)]-1,3,5-triazin-2-yl}amino)methanol, 2,4-diamino-6-diallylamino-1,3,5-triazine, ({bis[bis(hydroxymethyl)amino]-1,3,5-triazin-2-yl}(hydroxyl-methyl)amino)methanol, N2,N4-di-tert-butyl-1,3,5-triazine-2,4,6-triamine and N2,N4-bis(prop-2-en-1-yl)-1,3,5-triazine-2,4,6-triamine, in a total amount of from 0.003 wt.-% to 0.15 wt.-% based on the total weight of the CMP composition, (C) at least one amino acid (C) selected from the group consisting of glycine, alanine, leucine, valine, cysteine, serine and proline, or a salt thereof, in a total amount of from 0.2 wt.-% to 0.9 wt-% based on the total weight of the CMP composition, (D) hydrogen peroxide in a total amount of from 0.2 wt.-% to 2 wt.-% based on the total weight of the CMP composition, and (E) an aqueous medium, wherein the CMP composition has a pH of from 7 to 10.

12. A process for the manufacture of a semiconductor device comprising the chemical mechanical polishing of a substrate used in the semiconductor industry wherein the substrate comprises (i) cobalt and/or (ii) a cobalt alloy in the presence of the CMP composition of claim 11.

13. The process according to claim 12, wherein the static etch rate (SER) of cobalt is below 100 Å/min.

14. The process according to claim 12, wherein the cobalt material removal rate (MRR) is in a range of from 300 to 6000 Å/min.

Description

[0165] The figures show:

[0166] FIG. 1: Schematic illustration of the variation of the shape factor with the shape of a particle

[0167] FIG. 2: Schematic illustration of the variation of the sphericity with the elongation of a particle

[0168] FIG. 3: Schematic illustration of the Equivalent Circle Diameter (ECD)

[0169] 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

EXAMPLES AND COMPARATIVE EXAMPLES

[0170] The general procedure for the CMP experiments is described below.

[0171] Standard CMP process for 200 mm Co/Co wafers:

Strasbaugh nSpire (Model 6EC), ViPRR floating retaining ring Carrier;

TABLE-US-00001 down pressure: 1.5 psi; back side pressure: 1.0 psi; retaining ring pressure: 1.0 psi; polishing tablet/carrier speed: 130/127 rpm; slurry flow rate: 300 ml/min; polishing time: 15 s; (Co) 60 s; (Cu) polishing pad: Fujibo H800; backing film: Strasbaugh, DF200 (136 holes); conditioning tool: Strasbaugh, soft brush, ex-situ; after each wafer the pad is conditioned for the next processing of an other wafer by 2 sweeps with 5 lbs down force. The brush is soft. This means even after 200 sweeps the brush will not have caused a significant removal rate on the soft polishing pad.

[0172] Three dummy TEOS wafers are polished with 60 s before the metal wafers are polished (Co wafer is polished for 15 s).

[0173] The slurry is stirred in the local supply station.

[0174] Standard analysis procedure for metal blanket wafers:

[0175] Removal rate is determined by difference of weight of the wafers pre and post CMP by a Sartorius LA310 S scale or a NAPSON 4-point probe station.

[0176] The radial uniformity of removal rate is assessed by 39 point diameter scan (range) using NAPSON 4-point probe station.

[0177] Standard consumables for CMP of metal film coated wafers:

Co films: 2000 A PVD Co on Ti liner (Supplier: AMT);
The pH-value is measured with a pH combination electrode (Schott, blue line 22 pH electrode).

[0178] Standard procedure for determination of the Co static etch rate (Co-SER):

[0179] Co-SER experiments were carried on as the following. 2.5×2.5 cm PVD Co (from AMT) were cut and washed with DI water. Co film thickness (dbefore) was measured with a 4-point probe. 400 ml of fresh prepared slurry with 0.5% H2O2 was put in a beaker and brought to 50° C. afterwards. Co coupon was placed into the slurry and kept in the slurry for 3 min. Then the coupon was washed and dried with N2. The Co film thickness (dafter) was measured with the same device again. The Co-SER was determined by the following formula:

SER (A/min)=(dbefore−dafter)/3

[0180] Standard procedure for slurry preparation:

[0181] An aqueous solution of glycine 10 wt. % is prepared by dissolving the desired amount of glycine in ultra-pure water. After stirring for 20 min the solution is neutralized and the pH is adjusted to pH 8.05±0.1 by adding an 4.8 wt. % aqueous solution of KOH. Balance water may be added to adjust concentration. An aqueous stock solution of the respective triazine derivative (B) 1 wt. % is prepared by dissolving the desired amount of triazine derivative (B) in ultra-pure water and stirring for 30 minutes until all of the solid of the triazine derivative (B) is dissolved.

[0182] To prepare the CMP slurry of the examples the glycine (amino acid (C)) solution, the triazine derivative (corrosion inhibitor (B)) solution are mixed and a solution of colloidal silica particles (20% stock solution of (A) for example Fuso® PL 3) is added under continuous stirring. After the complete addition of the desired amount of abrasive (A) the dispersion is stirred for additional 5 minutes. Then the pH is adjusted to 8.3±0.1 by adding an 4.8 wt. % aqueous solution of KOH. Balance water is added under stirring to adjust the concentration of the CMP slurry to the values listed in the tables 2 and table 3 of the examples and comparative examples below. Thereafter the dispersion is filtered by passing through a 0.2 μm filter at room temperature. The desired amount of H.sub.2O.sub.2 (D) is added right before (1 to 15 min) before the slurry is used for CMP.

Inorganic particles (A) used in the Examples

[0183] 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-00002 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 99.78 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

[0184] 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 2 k, 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.

[0185] A2 are agglomerated particles with a specific surface area of around 90 m.sup.2/g having an average primary particle size (d1) of 35 nm and an average secondary particle size (d2) of 75 nm (as determined using dynamic light scattering techniques via a Horiba instrument) (for example Fuso® PL-3H) were used.

TABLE-US-00003 TABLE 2 CMP compositions of the example 1 and of the comparative example V1, their pH values, concentration, Co-SER data as well as their Co-MRR data in the process of chemical-mechanical polishing of 200 mm Co wafers using these compositions, wherein the aqueous medium (E) of the CMP compositions is de-ionized water. The amounts of the components (A), (B), (C) and (D) are specified in weight percent (wt. %) by weight of the corresponding CMP composition. If the amounts of the components other than (E) are in total y % by weight of the CMP composition, then the amount of (E) is (100 − y) % by weight of the CMP composition. Comparative Example V1 Example 1 Particles (A) A1 0.5 wt. % A1 0.5 wt. % H.sub.2O.sub.2 (D) H.sub.2O.sub.2 1 wt. % H.sub.2O.sub.2 0.5 wt. % Compound (B) BTA 6,6′,6″-(1,3,5- (Benzotriazole) Triazine-2,4,6- 0.03 wt % triyltriimino)trihexanoic acid 0.03 wt % Glycin (C) 0.75 wt. % 0.75 wt. % pH 8.3 8.3 Co-MRR [Å/min] 718 Co-SER [Å/min] 654 15

[0186] The CMP compositions according to the invention are showing an improved polishing performance in terms of cobalt material removal rates (MRR) [Å/min] and a drastic decrease in the Co etching rates as can be demonstrated by the examples shown in table 2.