Chemical mechanical polishing solution

Abstract

The present invention discloses a chemical mechanical polishing slurry, the chemical mechanical polishing slurry comprises silica abrasive particles, a corrosion inhibitor, a complexing agent, an oxidizer, and at least one kind of polyacrylic acid anionic surfactant. The polishing slurry of the present invention can decrease the removal rate of tantalum while increasing the removal rate of copper, and reduce copper dishing and dielectric erosion after polish.

Claims

1. A chemical mechanical polishing slurry for polishing copper, characterized in that the chemical mechanical polishing slurry consists of silica abrasive particles, a corrosion inhibitor, a complexing agent, an oxidizer, water and at least one kind of polyacrylic acid anionic surfactant, wherein the corrosion inhibitor is one or more azole compounds selected from triazoles and tetrazoles that do not contain a benzene moiety; wherein the complexing agent is one or more selected from the group consisting of glycine, alanine, valine, leucine, proline, phenylalanine, tyrosine, tryptophan, lysine, arginine, histidine, serine, aspartic acid, glutamic acid, asparagine and glutamine, wherein an average particle size of the silica abrasive particles is 60-140 nm, wherein a particle size distribution index (PdI) of the silica abrasive particles is 0.18-0.60, and wherein a pH of the chemical mechanical polishing slurry is 6-9.

2. The chemical mechanical polishing slurry according to claim 1, wherein a concentration of the silica abrasive particles is 0.05-2 wt %.

3. The chemical mechanical polishing slurry according to claim 1, wherein the polyacrylic acid anionic surfactant is selected from the group consisting of polyacrylic acid homopolymers, polyacrylic acid copolymers, a salt of polyacrylic acid homopolymers, and a salt of polyacrylic acid copolymers.

4. The chemical mechanical polishing slurry according to claim 3, wherein the polyacrylic acid homopolymer is selected from the group consisting of a polyacrylic acid homopolymer and a polymaleic acid homopolymer.

5. The chemical mechanical polishing slurry according to claim 3, wherein the polyacrylic acid copolymer is selected from the group consisting of a polyacrylic acid—polyacrylate copolymer and a polyacrylic acid—polymaleic acid copolymer.

6. The chemical mechanical polishing slurry according to claim 3, wherein the salt of the polyacrylic acid homopolymer is selected from a sodium salt, a potassium salt and an ammonium salt of the polyacrylic acid homopolymer.

7. The chemical mechanical polishing slurry according to claim 3, wherein the salt of the polyacrylic acid copolymer is selected from a sodium salt, a potassium salt and an ammonium salt of the polyacrylic acid copolymer.

8. The chemical mechanical polishing slurry according to claim 1, wherein a molecular weight of the polyacrylic acid anionic surfactant is 1,000-10,000.

9. The chemical mechanical polishing slurry according to claim 8, wherein the molecular weight of the polyacrylic acid anionic surfactant is 2,000-5,000.

10. The chemical mechanical polishing slurry according to claim 1, wherein a concentration of the polyacrylic acid anionic surfactant is 0.0005-0.5 wt %.

11. The chemical mechanical polishing slurry according to claim 1, wherein the complexing agent is present in an amount of 0.1-5 wt %.

12. The chemical mechanical polishing slurry according to claim 1, wherein the corrosion inhibitor is one or more selected from the group consisting of 1,2,4-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, 5-carboxy-3-amino-1,2,4-triazole, 3-amino-5-mercapto-1,2,4-triazole, 5-acetic acid-1H-tetrazole, 5-methyltetrazole and 5-amino-1H-tetrazole.

13. The chemical mechanical polishing slurry according to claim 1, wherein the corrosion inhibitor is present in an amount of 0.001-2 wt %.

14. The chemical mechanical polishing slurry according to claim 1, wherein the oxidizer is one or more selected from the group consisting of hydrogen peroxide, urea peroxide, peroxyformic acid, peracetic acid, persulfate, percarbonate, periodic acid, perchloric acid, perboric acid, potassium permanganate, and iron nitrate.

15. The chemical mechanical polishing slurry according to claim 14, wherein the oxidizer is hydrogen peroxide.

16. The chemical mechanical polishing slurry according to claim 1, wherein a concentration of the oxidizer is 0.05-5 wt %.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows the surface topography of the dense array area in the copper patterned wafer after polishing by the contrastive embodiment 5.

(2) FIG. 2 shows the surface topography of the dense array area in the copper patterned wafer after polishing by the embodiment 25.

DETAILED DESCRIPTION OF THE INVENTION

(3) The present invention is further described in the way of embodiments, but the present invention is not limited to the scope of the embodiments.

(4) Table 1 shows embodiments 1-4 of the chemical mechanical polishing slurry of the present invention. According to the formula given in the table, the components except the oxidizer are mixed homogeneously and the water makes up the quality percentage to 100%, KOH or HNO.sub.3 was added to adjust pH to the desired value. The oxidizer was added before using and then mixing homogeneously.

(5) TABLE-US-00001 TABLE 1 the polishing slurry of the embodiments 1~24 of the present invention polyacrylic anionic abrasive particle corrosion inhibitor surfactant complexing agent oxidizing agent con- con- con- con- con- polishing tent partical particle size tent specific tent specific tent specific tent specific slurry (%) size distribution (%) substance (%) substance (%) substance (%) substance pH Embodi- 0.5 110 0.16 0.15 1,2,4-triazole 0.002 polyacrylic 1 glycine 1 hydrogen 7 ment 1 nm acid peroxide Mw = 3000 Embodi- 0.05 90 0.3 0.08 3-amino- 0.001 polymaleic 2 ethylenediamine 2.5 ammonium 5 ment 2 nm 1,2,4-triazole acid disuccinic acid persulfate Mw = 2000 Embodi- 0.1 90 0.20 0.5 5-diamino- 0.01 polyacrylic 0.5 cyclohexanediamine 3.5 hydrogen 6 ment 3 nm 1,2,4-triazole acid tetraacetic acid peroxide Mw = 1000 Embodi- 0.2 80 0.1 1 3,5-diamino- 0.01 polymethyl 2.5 ethylenediamine 4.5 urea 6 ment 4 nm 1,2,4-triazole methacrylate tetraacetic acid peroxide Mw = 5000 Embodi- 0.3 100 0.12 2 5- 0.003 ammonium 3 triethylenetetramine 0.1 hydrogen 5 ment 5 nm methyltetrazole polyacrylate hexaacetic acid peroxide and 5-amino- Mw = 3000 1H-tetrazole Embodi- 0.5 90 0.18 0.001 5-amino- 0.01 polyacrylic 1 leucine 3 peracetic 7 ment 6 nm 1,2,4-triazole acid acid Mw = 10000 Embodi- 2 70 0.6 0.06 5-acetic acid- 0.02 ammonium 0.5 alanine 0.05 hydrogen 7 ment 7 nm 1H-tetrazole polyacrylate peroxide Mw = 3000 Embodi- 1.5 70 0.26 0.5 5-carboxy- 0.01 potassium 5 threonine 1 Potassium 5 ment 8 nm 3-amino- polyacrylate persulfate 1,2,4-triazole Mw = 3000 Embodi- 2 60 0.6 0.8 4-amino- 0.01 polyacrylic 1 valine 1 ammonium 5 ment 9 nm 1,2,4-triazole acid persulfate Mw = 3000 Embodi- 0.5 60 0.2 0.01 3,5-diamino- 0.005 polymaleic 2 aminotriacetic 5 Ferric 5 ment 10 nm 1,2,4-triazole acid acid nitrate Mw = 3000 Embodi- 0.1 120 0.1 0.5 3-amino- 0.001 acrylic acid- 0.15 phenylalanine 3 hydrogen 5 ment 11 nm 1,2,4-triazole acrylamide peroxide copolymer Mw = 8000 Embodi- 0.15 120 0.15 0.15 5-amino- 0.01 acrylic acid- 1.8 asparagine 2 hydrogen 6 ment 12 nm 1H-tetrazole acrylic ester peroxide copolymer Mw = 4000 Embodi- 0.25 80 0.22 0.005 4-amino- 0.02 polyacrylic 1.5 serine 2 perchloric 6 ment 13 nm 1,2,4-triazole acid acid Mw = 3000 Embodi- 0.8 60 0.25 1 5- 0.02 acrylic 1 proline 3 hydrogen 6 ment 14 nm methyltetrazole acid-maleic peroxide anhydride copolymer Mw = 6000 Embodi- 1 80 0.13 0.02 5-amino- 0.5 ammonium 3 tryptophan 1 hydrogen 6 ment 15 nm 1H-tetrazole polyacrylate peroxide salt Mw = 3000 Embodi- 2 80 0.16 0.5 3,5-diamino- 0.3 polyacrylic 1.2 valine 1 hydrogen 6 ment 16 nm 1,2,4-triazole acid peroxide Mw = 1000 Embodi- 0.5 140 0.1 0.1 4-amino- 0.001 Acrylic 0.8 aspartic acid 2 hydrogen 7 ment 17 nm 1,2,4-triazole acid-methyl peroxide methacrylate copolymer Mw = 4000 Embodi- 0.3 80 0.24 0.6 3,5-diamino- 0.002 Acrylic 3 glutamic acid 2 periodic 7 ment 18 nm 1,2,4-triazole acid-methyl acid methacrylate copolymer Mw = 2000 Embodi- 1 140 0.11 0.8 5-acetic 0.003 poly ethyl 1 arginine 1 perboric 6 ment 19 nm acid-1H- acrylate acid tetrazole Mw = 5000 Embodi- 0.5 80 0.22 0.05 4-amino- 0.005 polyacrylic 1.5 lysine 1 hydrogen 7 ment 20 nm 1,2,4-triazole acid peroxide Mw = 3500 Embodi- 1 80 0.24 0.3 3-amino- 0.1 polyacrylic 1.5 histidine 3 hydrogen 7.5 ment 21 nm 5-mercapto- acid peroxide 1,2,4-triazole Mw = 7000 Embodi- 0.2 70 0.23 0.09 3-amino- 0.2 polyacrylic 2 tyrosine 3 potassium 7 ment 22 nm 5-mercapto- acid permanganate 1,2,4-triazole Mw = 5000 Embodi- 0.5 100 0.16 0.005 5-carboxy- 0.0005 Acrylic 0.1 glutamine 2 peroxyformic 8 ment 23 nm 3-amino- acid-methyl acid 1,2,4-triazole methacrylate copolymer Mw = 6000 Embodi- 0.5 120 0.1 0.05 3-amino- 0.5 Acrylic 0.2 diethylenetriamine 2 Sodium 8 ment 24 nm 1,2,4-triazole acid-methyl pentaacetic acid percarbonate methacrylate copolymer Mw = 2300

Effect Embodiments

(6) Table 2 shows the embodiments 25˜35 and the contrastive embodiments 1˜6 of the chemical mechanical polishing slurry of the present invention. According to the formula given in the table, the components except the oxidizer are mixed homogeneously and the water makes up the quality percentage to 100%. KOH or HNO.sub.3 was added to adjust pH to the desired value. The oxidizing agent was added before using and then mixing homogeneously

(7) TABLE-US-00002 TABLE 2 contrastive embodiments 1~6 and embodiments 25~35 polyacrylic anionic surfactant specific abrasive particle corrosion inhibitor material complexing agent oxidizing agent polishing content partical particle size content specific content (monoester/ content specific content specific slurry (%) size distribution (%) substance (%) diester) (%) substance (%) substance pH contras- 0.2 40 0.7 0.1 1,2,4-triazole 0.01 polyacrylic 1 glycine 1 hydrogen 7 tive acid peroxide embodi- Mw = 3000 ment 1 contras- 0.2 150 0.05 0.05 1,2,4-triazole 0.01 polyacrylic 1 glycine 1 hydrogen 7 tive acid peroxide embodi- Mw = 3000 ment 2 contras- 0.2 110 0.12 0.05 1,2,4-triazole 0.01 polyacrylic 1 glycine 1 hydrogen 4 tive acid peroxide embodi- Mw = 3000 ment 3 contras- 0.2 110 0.12 0.05 1,2,4-triazole 0.01 polyacrylic 1 glycine 1 hydrogen 9 tive acid peroxide embodi- Mw = 3000 ment 4 contras- 0.2 110 0.12 0.05 1,2,4-triazole — — 1 glycine 1 hydrogen 7 tive peroxide embodi- ment 5 contras- 0.2 110 0.12 0.05 benzotriazole 0.01 polyacrylic 1 glycine 1 hydrogen 7 tive acid peroxide embodi- Mw = 3000 ment 6 embodi- 0.2 110 0.12 0.05 1,2,4-triazole 0.01 polyacrylic 1 glycine 1 hydrogen 7 ment 25 acid peroxide Mw = 3000 embodi- 0.2 80 0.6 0.05 1,2,4-triazole 0.01 ammonium 1 glycine 1 hydrogen 7 ment 26 polyacrylate peroxide Mw = 3000 embodi- 0.3 90 0.5 0.02 5-acetic 0.005 polyacrylic 1 glycine 1.5 hydrogen 6 ment 27 acid-1H- acid peroxide tetrazole Mw = 2000 embodi- 0.8 120 0.1 0.05 3-amino- 0.005 acrylic 2.5 glycine 2 hydrogen 5 ment 28 1,2,4-triazole acid-maleic peroxide anhydride copolymer Mw = 3000 embodi- 0.7 90 0.13 0.15 1,2,4-triazole 0.01 ammonium 1 glycine 1 hydrogen 7 ment 29 polyacrylate peroxide Mw = 2000 embodi- 0.6 90 0.3 1 4-amino- 0.06 polyacrylic 3 glycine 1.2 hydrogen 7.5 ment 30 1,2,4-triazole acid peroxide Mw = 5000 embodi- 0.15 80 0.6 0.5 1,2,4-triazole 0.05 acrylic 1.5 glycine 1 hydrogen 8 ment 31 acid-acrylic peroxide ester copolymer Mw = 5000 embodi- 0.1 110 0.21 0.08 1,2,4-triazole 0.02 potassium 0.5 ethylenediamine 0.5 hydrogen 6 ment 32 polyacrylate disuccinic peroxide Mw = 3000 acid embodi- 1 90 0.5 0.05 4-amino- 0.1 polyacrylic 3 proline 3 hydrogen 8 ment 33 1,2,4-triazole acid peroxide Mw = 4000 embodi- 0.3 80 0.4 0.8 1,2,4-triazole 0.003 potassium 2 glycine 2.5 hydrogen 8 ment 34 polyacrylate peroxide Mw = 3000 embodi- 0.5 120 0.11 0.005 5-amino- 0.001 ammonium 1.2 glycine 0.1 hydrogen 6.5 ment 35 1H-tetrazole polyacrylate peroxide Mw = 3500

(8) The copper (Cu) and tantalum (Ta) of the blanket wafers are polished by the polishing slurry of contrastive embodiments 1˜6 and embodiments 25˜35 of the present invention according to the following conditions.

(9) Polishing conditions: downforce: 1.5 psi, 2.0 psi; polishing platen/polishing head rotation speed: 73/67 rpm, polishing pad: IC1010, the flow rate of polishing slurry is 350 ml/min, polisher: 12″ Reflexion LK, polishing time: 1 min.

(10) Copper patterned wafers are polished by the polishing slurry of the contrastive embodiments and the present invention according to the following conditions.

(11) Polishing conditions: polishing platen/polishing head rotation speed: 73/67 rpm, polishing pad: IC1010, the flow rate of polishing slurry is 350 ml/min, polisher: 12″ Reflexion LK. The copper patterned wafer is polished on the polishing platen 1 with a downforce of 2 psi until that the remaining copper thickness is about 4000 Å, and then the remaining copper is removed on the polishing platen 2 with a downforce of 1.5 psi. The value of Cu dishing and erosion of the dielectric layer of the array of the 5/1 um (copper wire/silica) on the patterned wafer are measured by XE-300P atomic force microscope, as the result is shown in Table 3.

(12) TABLE-US-00003 TABLE 3 polishing effect of the polishing slurry of the contrastive embodiments 1~6 and the embodiments 25~35 removal rate of Cu removal rate polishing (Å/min) of Ta (Å/min) selectivity dishing value of the dielectric erosion value of polishing slurry 2.0 psi 1.5 psi 1.5 psi of Cu/Ta 5/1 um array (nm) the 5/1 um array (nm) contrastive 4500 2100 2 1050 / / embodiment 1 contrastive 3910 2102 2 1051 / / embodiment 2 Contrastive 6767 4880 8 610 111  10.5  embodiment 3 contrastive 2150 1500 3 500 / / embodiment 4 contrastive 7355 5204 50 104   89.1 59.2  embodiment 5 contrastive 1450 260 5 52 / / embodiment 6 embodiment 25 6461 4511 2 2256 43 0.2 embodiment 26 6299 4418 2 2209 45 0.3 embodiment 27 6286 4886 3 1629   43.1 0.3 embodiment 28 10714 5326 3 1775 / / embodiment 29 6403 4332 3 1444 51 5   embodiment 30 5592 2052 2 1026 45 0.8 embodiment 31 4211 1811 3 604 / / embodiment 32 4133 2242 5 448 / / embodiment 33 4109 2137 2 1069 / / embodiment 34 8622 4362 3 1454 56 4   embodiment 35 4134 1724 2 862 / /

(13) According to table 2 and table 3, it can be seen from the polishing slurry of the contrastive embodiment 1, 2 and the embodiment 25, 26 that when the abrasive particle size is large but the particle size distribution is narrow (PdI is small) or the abrasive particle size is small but the particle size distribution is wide (PdI is large), the removal rate of Cu is relatively lower. The Cu removal rate increases only when the particle size and the particle size distribution of abrasive particles vary within a certain range. The addition of polyacrylic acid anionic surfactant can suppress the removal rate of Ta to a relatively low removal rate, thus achieving a high removal rate selectivity of Cu to Ta, up to 2200. In addition, compared to the contrastive embodiments 1-6, the polishing slurry of the embodiment 25 can further control the dishing and dielectric erosion of the wafer on the basis of having an ultra-high polishing selectivity of Cu to Ta.

(14) Further referring to FIG. 1 and FIG. 2, they are the surface topography of the dense array area with a copper line width of 5 microns and a dielectric material width of 1 micron in the polished copper patterned wafer after using the polishing slurry of the contrastive embodiment 5 and embodiment 25, respectively. It can be seen from the figures that after polishing, Cu dishing is 89.1 nm and dielectric erosion is 59.2 nm when using the polishing slurry of the contrastive embodiment 5. However, the dishing is reduced to 43 nm and the dielectric erosion is reduced to 0.2 nm after polishing with embodiment 25. The polishing slurry of the present invention has a very significant improvement on the surface topography especially erosion after polishing. At the same time, by comparing the composition between the embodiment 25 and the contrastive embodiment 6, it can be found that the combination of benzotriazole, an azole corrosion inhibitor with benzene, and polyacrylic acid anionic surfactant can reduce the removal rate of tantalum, but also significantly suppress the removal rate of copper, so the copper cannot be effectively removed. Compared with embodiment 25 of the present invention, a combination of azole corrosion inhibitor without benzene and polyacrylic acid anionic surfactant is added into the polishing slurry of the contrastive embodiment 3 and 4, but the pH value of the contrastive embodiment 3 is too low, and the removal rate of copper and tantalum are relatively high, resulting in a large dishing and erosion value. However, the pH value of the contrastive embodiment 4 is too high that the removal rate of copper is greatly decreased, and copper cannot be effectively removed.

(15) In conclusion, the invention not only ensures high removal rate of copper, but also reduces defects of the surface by using abrasive particles within a certain range of PdI. By adding azole corrosion inhibitor without benzene and polyacrylic acid anionic surfactant into the polishing slurry, the high removal rate of copper is maintained, and the removal rate of tantalum barrier layer is reduced, so as to improve the polishing selectivity of the polishing slurry of the copper to tantalum barrier layer. The present invention can be used for polishing the wafers to reduce dishing and erosion, without copper residue, corrosion or other defects after polishing.

(16) The specific embodiment of the present invention has been described in detail above, but it is only an example, and the present invention is not limited to the specific embodiment described above. Any person skilled in the art can make alterations or modifications to the embodiments by the aforementioned technical contents, to form an equivalent and effective embodiment. Any amendments, equivalent changes and modifications to the above-mentioned embodiments based on the technical essence of the present invention, without departing from the technical solutions of the present invention, shall belong to the scope defined by the technical solutions of the present invention.