Chemical mechanical polishing composition and application thereof

Abstract

The invention discloses a chemical mechanical polishing composition and application thereof. The composition comprises a modified silicon dioxide abrasive, a complexing agent, a corrosion inhibitor, a dispersing agent, an oxidizing agent and water. The modified silicon dioxide abrasive is of a core-shell structure and comprises a shell layer and a core layer, the core layer is silicon dioxide sol, the shell layer is an amino-containing polymer, and the amino-containing polymer is a polymerization product of polyphenol and polyethylene polyamine. According to the chemical mechanical polishing composition, the surface of an abrasive material used by the chemical mechanical polishing composition is subjected to coating modification, an organic protection layer is generated, the hardness of the abrasive material is reduced, and the dispersity of the abrasive material in a solution is improved, so that aggregation of the abrasive material in the solution is reduced, and generation of wafer surface defects in the polishing process can be reduced; and moreover, the coating contains amino groups, so that the polishing rate of the metal copper can be increased.

Description

Technical Field

[0001] The present invention relates to the field of chemical mechanical polishing, and particularly to a modified silica abrasive chemical mechanical polishing composition and its application. Background Art

[0002] Chemical mechanical polishing technology is one of the key steps in the integrated circuit manufacturing process. Its main principle is to combine the mechanical action of abrasives and the chemical action of chemical active solutions to planarize the surface of the substrate. In the polishing process of the metal layer, usually an oxidant first forms a metal oxide with relatively low hardness on the metal surface, and then the abrasive grinds and removes this oxide layer mechanically, generating a new metal surface that continues to be oxidized. The above process is repeated until the polishing is completed.

[0003] Currently, silica is one of the most widely used abrasives in chemical mechanical polishing. However, due to its relatively stable nature, it is difficult to remove by redox methods. Therefore, polishing compositions with relatively high solid contents are usually required. Among them, silica sol, as a commonly used abrasive, although having good surface contaminant indicators and stability, has the problem of poor abrasive dispersibility and is prone to generating more defects on the surface of copper metal during the polishing process. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a chemical mechanical polishing composition. By adding a modified silica abrasive to the polishing composition, the polishing rate of copper metal is increased, and at the same time, the defects on the surface of the polished wafer are reduced.

[0005] To achieve the above invention purposes, the present invention adopts the following technical solutions:

[0006] A chemical mechanical polishing composition, the polishing composition includes a modified silica abrasive, a complexing agent, a corrosion inhibitor, a dispersant, an oxidant and water; wherein, the modified silica abrasive has a core-shell structure, including a shell layer and a core layer, the core layer is silica sol, the shell layer is an amino-containing polymer, the amino-containing polymer is a polymerization product of polyphenol and polyethylenepolyamine, and the average particle size of the modified silica abrasive is 3 - 10 nm larger than the average particle size before modification.

[0007] Wherein, the polyphenol is selected from at least one of dopamine, tannic acid, catechol, gallic acid, propyl gallate or catechin; the polyamine is selected from at least one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hydroxymethyldiethylenetriamine or hydroxyethyldiethylenetriamine.

[0008] Preferably, by mass percentage, the polishing composition comprises 0.5%-3% of modified silica abrasive, 5%-15% of complexing agent, 0.02%-1.5% of corrosion inhibitor, 0.01%-0.1% of dispersant, 0.1%-3% of oxidant, and the balance is water.

[0009] Preferably, the polyphenol is selected from one or more of dopamine, catechol, catechin, gallic acid, and tannic acid.

[0010] Preferably, the polyethylenepolyamine is selected from one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0011] More preferably, the polyethylenepolyamine is selected from triethylenetetramine and / or tetraethylenepentamine.

[0012] More preferably, the polyphenol is selected from dopamine and / or catechol, and further preferably dopamine.

[0013] Preferably, the molar dosage ratio of the polyphenol to the polyethylenepolyamine is 4:1 - 1:4.

[0014] More preferably, the molar dosage ratio of the polyphenol to the polyethylenepolyamine is 3:1 - 1:2, preferably 3:1, 2:1, 1:1, or 1:2.

[0015] Preferably, the average particle size of the modified silica abrasive is 30 - 170 nm, preferably 40 - 100 nm, more preferably 43 - 94 nm, and even more preferably 43, 84, 85, 86, 87, 88, 89, 90, 91, or 94 nm.

[0016] Preferably, the complexing agent is selected from one or more of amino acids and carboxylic acids.

[0017] Preferably, the corrosion inhibitor is selected from one or more of benzotriazole, methylbenzotriazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, 2,2'-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol, carboxybenzotriazole, 4-amino-1,2,4-triazole, 5-methyl-tetrazole, 5-amino-tetrazole, 5-phenyltetrazole, mercaptophenyltetrazole, benzimidazole, naphthotriazole, and 2-mercapto-benzothiazole.

[0018] Preferably, the dispersant is selected from one or more of sodium dodecylbenzenesulfonate, sodium dodecylsulfonate, sodium dodecylsulfate, polyethylene glycol, polyacrylic acid, polyacrylate, and fatty alcohol polyoxyethylene ether.

[0019] Preferably, the oxidant is hydrogen peroxide, peracetic acid, potassium persulfate, and / or ammonium persulfate.

[0020] Another aspect of the present invention is to provide an application of the above chemical mechanical polishing composition in copper chemical mechanical polishing.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] By adding polyphenols and polyethylenepolyamines to an alkaline solution containing silica sol, the present invention coats an organic protective layer on the surface of the silica sol, which can reduce the hardness of the silica abrasive, increase the dispersibility of the abrasive in the polishing composition, reduce the aggregation between abrasives, and thus reduce the generation of surface defects on the wafer during the polishing process. At the same time, since the coated organic protective layer has amino groups, it can also improve the polishing rate of copper. Detailed Embodiments

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Those not specified in the examples are carried out under conventional conditions or conditions recommended by the manufacturer. Those reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase.

[0024] The present invention provides a chemical mechanical polishing composition, comprising a modified silica abrasive, a complexing agent, a corrosion inhibitor, a dispersant, an oxidizing agent and water; wherein, the modified silica abrasive has a core-shell structure, including a shell layer and a core layer, the core layer is silica sol, and the shell layer is an amino-containing polymer, and the amino-containing polymer is a polymerization product of polyphenols and polyethylenepolyamines;

[0025] The polyphenols are selected from at least one of dopamine, tannic acid, catechol, gallic acid, propyl gallate or catechin; the polyamines are selected from at least one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hydroxymethyldiethylenetriamine or hydroxyethyldiethylenetriamine.

[0026] Among them, the average particle size of the modified silica abrasive is 3-10 nm larger than the average particle size before modification.

[0027] In the embodiments of the present invention, by mass percentage, the chemical mechanical polishing composition comprises 0.5%-3% of the modified silica abrasive, 5%-15% of the complexing agent, 0.02%-1.5% of the corrosion inhibitor, 0.01%-0.1% of the dispersant, 0.1%-3% of the oxidizing agent, and the balance is water.

[0028] Another key point of the present invention lies in coating and modifying silica abrasives with amino group-containing polymer organic substances. The amino group-containing polymer is a polymerization product of polyphenol and polyethylenepolyamine. Among them, polyphenol has oxidizing property and is prone to undergo Michael addition reaction and Schiff base effect with polyethylenepolyamine in a weakly alkaline solution, generating a phenolic amine network structure layer. Therefore, by adding polyphenol and polyethylenepolyamine to the alkaline solution containing silica sol, an organic protective layer can be formed on the surface of silica sol particles.

[0029] The amino group-containing polymer formed by the polymerization of polyphenol and polyethylenepolyamine serves as the shell layer. Since the hardness of the organic protective layer is usually lower than that of silica, it is equivalent to covering a relatively soft "outer coat" on the surface of the hard silica abrasive, thereby reducing the hardness of the abrasive as a whole. In this way, during the polishing process, the wafer surface will not be damaged by excessive scratching due to the overly hard abrasive. In addition, after the amino group-containing polymer is coated on the surface of the silica abrasive, it prevents the aggregation of abrasive particles, enabling the abrasive to be more evenly dispersed in the solution, ensuring the stability of the performance of the polishing composition. During the polishing process, the action of the abrasive on the wafer surface is more uniform and gentle, and problems such as scratches caused by local over-grinding or abrasive aggregation will not occur, thus effectively reducing the generation of surface defects on the wafer during the polishing process and improving the flatness and smoothness of the wafer surface. The organic substances on the surface coating make the surface properties of the abrasive closer to those of the organic polishing pad, increasing the compatibility with the polishing pad. The amino groups on the coating have certain chemical activity, and they can interact with the surface of metallic copper, thereby improving the polishing rate of metallic copper.

[0030] Among them, the preparation method of the modified silica abrasive is as follows: First, uniformly disperse the silica sol in an alkaline solution to obtain a dispersion with a pH value of 8 - 10; then add polyphenol and polyethylenepolyamine and react to obtain modified silica, that is, an organic protective layer containing amino group-containing polymer is coated on the surface of silica.

[0031] Among them, there are no restrictions on the preparation method of the silica sol, and conventional methods in the art can be used. The particle size of the silica sol is 20 - 200 nm, for example, including but not limited to 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, preferably 30 - 160 nm; the solid content (mass fraction) of the silica sol is 5 - 50 wt%, for example, including but not limited to 5%, 10%, 20%, 30%, 40%, 50%, preferably 20 - 40 wt%. The particle size and solid content of the silica sol affect the balance between mechanical grinding and chemical corrosion during the polishing process. Excessive particle size may cause scratches, while appropriate particle size and solid content can optimize the removal rate and reduce defects.

[0032] In the embodiments of the present invention, the polyalkylene polyamine is selected from one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0033] From the perspective of polishing effect, the polyalkylene polyamine is preferably triethylenetetramine and / or tetraethylenepentamine. The possible reason is that the amino-containing polymers formed by triethylenetetramine and tetraethylenepentamine have a suitable steric hindrance effect. In the polishing composition, this steric hindrance can effectively prevent the aggregation of silica abrasive particles, enabling the abrasive particles to be uniformly dispersed in the solution, increasing the effective contact area between the abrasive and the copper surface, and improving the polishing efficiency. At the same time, the uniformly dispersed abrasive particles can perform grinding more smoothly during the polishing process, avoiding local over-grinding or uneven grinding caused by particle aggregation, which is beneficial to reducing surface defects.

[0034] In the embodiments of the present invention, the polyphenol is selected from one or more of dopamine, catechol, catechin, gallic acid, and tannic acid. From the perspective of polishing effect, the polyphenol is preferably triethylenedopamine and / or catechol, and further preferably dopamine.

[0035] In the embodiments of the present invention, the molar dosage ratio of the polyphenol to the polyethylenepolyamine is 4:1 - 1:4. Considering the polishing effect, the molar dosage ratio of the polyphenol to the polyethylenepolyamine is preferably 3:1 - 1:2, for example, it can be 3:1, 2:1, 1:1 or 1:2, and the dosage ratios defined by any two of the foregoing. When the molar dosage ratio is within the range of 3:1 - 1:2, the polyphenol and the polyethylenepolyamine can form a structurally complete and stable phenolic amine network structure. The phenolic amine network structure layer formed has a moderate degree of coating on the silica abrasive, neither making the abrasive too soft due to an overly thick organic film or excessive functional groups and losing the ability to grind the copper surface, nor making the hardness of the abrasive still too high due to an overly thin organic film or insufficient functional groups, resulting in defects such as scratches on the wafer surface.

[0036] In the embodiments of the present invention, the alkaline solution is selected from boric acid - potassium chloride - potassium hydroxide buffer solution, dipotassium hydrogen phosphate - potassium hydroxide buffer solution, dipotassium hydrogen phosphate - potassium dihydrogen phosphate buffer solution or Tris - HCl buffer solution; preferably, the alkaline solution is selected from dipotassium hydrogen phosphate - potassium dihydrogen phosphate buffer solution or Tris - HCl buffer solution.

[0037] In the present invention, the modified silica abrasive particles are suspended in the liquid carrier of the chemical mechanical polishing composition, so that the chemical mechanical polishing composition is in a stable colloidal state. The addition amount of the modified silica abrasive is generally 0.1 wt% - 10 wt% of the total mass of the polishing composition, for example, including but not limited to 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%. Preferably, considering higher polishing rates, lower defects and better storage stability, the addition amount of the modified silica abrasive is preferably 0.5 wt% - 3 wt% of the total amount of the polishing composition.

[0038] The chemical mechanical polishing composition of the present invention may contain one or more complexing agents. Preferably, the complexing agent is an amino acid and a carboxylic acid. Such amino acids include but are not limited to alanine, arginine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine and their mixtures. Preferably, the amino acid is selected from the group consisting of aspartic acid, alanine, arginine, glutamine, glycine, leucine, lysine, serine and their mixtures, more preferably, the amino acid is selected from the group consisting of aspartic acid, alanine, glutamine, glycine, lysine, serine and their mixtures, even more preferably, the amino acid is selected from the group consisting of aspartic acid, alanine, glycine, serine and their mixtures, and most preferably, the amino acid is aspartic acid. The carboxylic acids include but are not limited to malic acid, malonic acid, tartaric acid, citric acid, oxalic acid, gluconic acid, lactic acid.

[0039] The complexing agent can be included as an initial component in the chemical mechanical polishing composition in an amount of 2 wt% to 20 wt%, more preferably 5 wt% to 20 wt%, and even more preferably 5 wt% to 15 wt%.

[0040] The chemical mechanical polishing composition of the present invention may include one or more corrosion inhibitors. Conventional corrosion inhibitors can be used. Corrosion inhibitors include but are not limited to benzotriazole, methylbenzotriazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, 2,2'-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol, carboxybenzotriazole, 4-amino-1,2,4-triazole, 5-methyl-tetrazole, 5-amino-tetrazole, 5-phenyltetrazole, mercaptophenyltetrazole, benzimidazole, naphthotriazole, and 2-mercapto-benzothiazole.

[0041] The corrosion inhibitor can be included in the chemical mechanical polishing composition in a conventional amount. Preferably, the amount of the corrosion inhibitor included is 0.001 wt% - 3 wt% of the chemical mechanical polishing composition, more preferably 0.01 wt%

[0042] - 2 wt%, and even more preferably 0.02 wt% - 1.5 wt%.

[0043] The chemical mechanical polishing composition of the present invention may include one or more dispersants. Conventional dispersants can be used. Dispersants include but are not limited to sodium dodecylbenzenesulfonate, sodium dodecylsulfonate, sodium dodecylsulfate, polyethylene glycol (200, 400, 600, 800, 2000, 4000, etc.), polyacrylic acid (molecular weight 1000, 2000, 4000, 10000, 100000, etc.), polyacrylate, and fatty alcohol polyoxyethylene ether.

[0044] The dispersant can be included in the chemical mechanical polishing composition in a conventional amount. Preferably, the amount of the dispersant included is 0.001 wt% - 2 wt% of the chemical mechanical polishing composition, more preferably 0.01 wt% - 1 wt%, and even more preferably 0.01 wt% - 0.1 wt%.

[0045] The chemical mechanical polishing composition of the present invention contains one or more oxidizing agents, and these oxidizing agents are selected from the group consisting of: hydrogen peroxide, monopersulfate, iodate, magnesium metaperphthalate, peracetic acid and other peracids, persulfate, bromate, perbromate, persulfate, peracetic acid, periodate, nitrate, iron salt, cerium salt, Mn(III) salt, Mn(IV) salt and Mn(VI) salt, silver salt, copper salt, chromium salt, cobalt salt, halogen, hypochlorite and mixtures thereof. Preferably, the oxidizing agent is selected from the group consisting of: hydrogen peroxide, perchlorate, perbromate, periodate, persulfate and peracetic acid. Most preferably, the oxidizing agent is hydrogen peroxide.

[0046] The chemical mechanical polishing composition may contain 0.01 wt% - 10 wt%, preferably 0.1 wt% - 5 wt%, more preferably 0.1 wt% - 3 wt% of the oxidizing agent.

[0047] The chemical mechanical polishing composition of the present invention further contains water. Preferably, the water contained in the chemical mechanical polishing composition is at least one of deionized water and distilled water to limit incidental impurities.

[0048] The chemical mechanical polishing composition in the present invention can be prepared by any suitable method, and a batch or continuous method can be selected for preparation. Specifically, the chemical mechanical polishing composition can be prepared by combining the components herein in any order, and the components refer to each individual component, such as modified silica abrasive particles, complexing agent, corrosion inhibitor and oxidizing agent.

[0049] The chemical mechanical polishing composition of the present invention can be used to polish various substrates. For a given substrate or material, such as dielectrics and metals, the modified silica abrasive particles of the present invention are adjustable. Such dielectric materials include but are not limited to TEOS and low-k films (low dielectric constant films). Metals include but are not limited to copper and Ta.

[0050] Preferably, the modified silica abrasive of the present invention is contained in the chemical mechanical polishing composition to preferably polish copper.

[0051] The polishing method of the present invention includes: providing a chemical mechanical polishing pad having a polishing surface; generating dynamic contact at the interface between the chemical mechanical polishing pad and the substrate; and dispensing the chemical mechanical polishing composition of the present invention onto the polishing surface of the chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate; wherein at least some of the dielectric material is polished off the substrate.

[0052] The above and other advantages of the present invention can be better understood through the following examples, but the following examples are not intended to limit the scope of the present invention.

[0053] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; unless otherwise specified, the reagents, materials, etc. used in the following examples can all be obtained from commercial sources.

[0054] <Preparation of Modified Silica Abrasive>

[0055] Modified silica abrasive B1:

[0056] Disperse 2000 g of silica sol A5 (silica particle size is 81 nm, solid content is 35%) evenly into 10000 mL of Tris-HCl solution to make its pH value 8.5, then add 33.00 g of dopamine, stir and react at a stirring speed of 40 rpm for 30 min, then add 22.23 g of diethylenetriamine (the molar ratio of dopamine to diethylenetriamine is 1:1), continue to stir and react at room temperature for 6 h, and finally obtain modified silica abrasive B1 by centrifugal filtration.

[0057] Modified silica abrasive B2:

[0058] Disperse 2000 g of silica sol A5 (silica particle size is 81 nm, solid content is 35%) evenly into 10000 mL of Tris-HCl solution to make its pH value 8.5, then add 33.00 g of dopamine, stir and react at a stirring speed of 40 rpm for 30 min, then add 31.50 g of triethylenetetramine (the molar ratio of dopamine to triethylenetetramine is 1:1), continue to stir and react at room temperature for 6 h, and finally obtain modified silica abrasive B2 by centrifugal filtration.

[0059] Modified silica abrasive B3:

[0060] Disperse 2000 g of silica sol A5 (silica particle size is 81 nm, solid content is 35%) evenly into 10000 mL of Tris-HCl solution to make its pH value 8.5, then add 33.00 g of dopamine, stir and react at a stirring speed of 40 rpm for 30 min, then add 40.78 g of tetraethylenepentamine (the molar ratio of dopamine to tetraethylenepentamine is 1:1), continue to stir and react at room temperature for 6 h, and finally obtain modified silica abrasive B3 by centrifugal filtration.

[0061] Modified silica abrasive B4:

[0062] 2000 g of silica sol A5 (with a silica particle size of 81 nm and a solid content of 35%) was uniformly dispersed into 10000 mL of Tris-HCl solution to make its pH value 8.5. Then, 33.00 g of dopamine was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then, 50.06 g of pentaethylenehexamine (the molar ratio of dopamine to pentaethylenehexamine was 1:1) was added, and the reaction was continued with stirring at room temperature for 6 h. Finally, the modified silica abrasive B4 was obtained by centrifugal filtration.

[0063] Modified silica abrasive B5:

[0064] 2000 g of silica sol A5 (with a silica particle size of 81 nm and a solid content of 35%) was uniformly dispersed into 10000 mL of Tris-HCl solution to make its pH value 8.5. Then, 23.72 g of catechol was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then, 31.50 g of triethylenetetramine (the molar ratio of catechol to triethylenetetramine was 1:1) was added, and the reaction was continued with stirring at room temperature for 6 h. Finally, the modified silica abrasive B5 was obtained by centrifugal filtration.

[0065] Modified silica abrasive B6:

[0066] 2000 g of silica sol A5 (with a silica particle size of 81 nm and a solid content of 35%) was uniformly dispersed into 10000 mL of Tris-HCl solution to make its pH value 8.5. Then, 62.53 g of catechin was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then, 40.78 g of tetraethylenepentamine (the molar ratio of catechin to tetraethylenepentamine was 1:1) was added, and the reaction was continued with stirring at room temperature for 6 h. Finally, the modified silica abrasive B6 was obtained by centrifugal filtration.

[0067] Modified silica abrasive B7:

[0068] 2000 g of silica sol A5 (with a silica particle size of 81 nm and a solid content of 35%) was uniformly dispersed into 10000 mL of Tris-HCl solution to make its pH value 8.5. Then, 36.62 g of gallic acid was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then, 40.78 g of tetraethylenepentamine (the molar ratio of gallic acid to tetraethylenepentamine was 1:1) was added, and the reaction was continued with stirring at room temperature for 6 h. Finally, the modified silica abrasive B7 was obtained by centrifugal filtration.

[0069] Modified silica abrasive B8:

[0070] 2000 g of silica sol A5 (with a silica particle size of 81 nm and a solid content of 35%) was uniformly dispersed into 10000 mL of Tris-HCl solution to make its pH value 8.5. Then, 366.44 g of tannic acid was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then, 40.78 g of tetraethylenepentamine (the molar ratio of tannic acid to tetraethylenepentamine was 1:1) was added, and the reaction was continued by stirring at room temperature for 6 h. Finally, the modified silica abrasive B8 was obtained by centrifugal filtration.

[0071] Modified silica abrasive B9:

[0072] 2000 g of silica sol A1 (with a silica particle size of 30 nm and a solid content of 30%) was uniformly dispersed into 10000 mL of Tris-HCl solution to make its pH value 9.0. Then, 66.00 g of dopamine was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then, 40.78 g of tetraethylenepentamine (the molar ratio of dopamine to tetraethylenepentamine was 2:1) was added, and the reaction was continued by stirring at room temperature for 6 h. Finally, the modified silica abrasive B9 was obtained by centrifugal filtration.

[0073] Modified silica abrasive B10:

[0074] 2000 g of silica sol A2 (with a silica particle size of 40 nm and a solid content of 36%) was uniformly dispersed into 10000 mL of Tris-HCl solution to make its pH value 8.5. Then, 66.00 g of dopamine was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then, 40.78 g of tetraethylenepentamine (the molar ratio of dopamine to tetraethylenepentamine was 2:1) was added, and the reaction was continued by stirring at room temperature for 6 h. Finally, the modified silica abrasive B10 was obtained by centrifugal filtration.

[0075] Modified silica abrasive B11:

[0076] 2000 g of silica sol A3 (with a silica particle size of 90 nm and a solid content of 33%) was uniformly dispersed into 10000 mL of Tris-HCl solution to make its pH value 8.0. Then, 66.00 g of dopamine was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then, 40.78 g of tetraethylenepentamine (the molar ratio of dopamine to tetraethylenepentamine was 2:1) was added, and the reaction was continued by stirring at room temperature for 6 h. Finally, the modified silica abrasive B11 was obtained by centrifugal filtration.

[0077] Modified silica abrasive B12:

[0078] 2000 g of silica sol A4 (with a silica particle size of 160 nm and a solid content of 39%) was uniformly dispersed into 10000 mL of Tris-HCl solution to make its pH value 8.5. Then, 66.00 g of dopamine was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then, 40.78 g of tetraethylenepentamine (the molar ratio of dopamine to tetraethylenepentamine was 2:1) was added, and the reaction was continued to stir at room temperature for 6 h. Finally, the modified silica abrasive B12 was obtained by centrifugal filtration.

[0079] Modified silica abrasive B13:

[0080] 2000 g of silica sol A5 (with a silica particle size of 81 nm and a solid content of 35%) was uniformly dispersed into 10000 mL of Tris-HCl solution to make its pH value 9.0. Then, 98.98 g of dopamine was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then, 31.50 g of triethylenetetramine (the molar ratio of dopamine to triethylenetetramine was 3:1) was added, and the reaction was continued to stir at room temperature for 6 h. Finally, the modified silica abrasive B13 was obtained by centrifugal filtration.

[0081] Modified silica abrasive B14:

[0082] 2000 g of silica sol A5 (with a silica particle size of 81 nm and a solid content of 35%) was uniformly dispersed into 10000 mL of Tris-HCl solution to make its pH value 8.5. Then, 132.00 g of dopamine was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then, 31.50 g of triethylenetetramine (the molar ratio of dopamine to triethylenetetramine was 4:1) was added, and the reaction was continued to stir at room temperature for 6 h. Finally, the modified silica abrasive B14 was obtained by centrifugal filtration.

[0083] Modified silica abrasive B15:

[0084] 2000 g of silica sol A5 (with a silica particle size of 81 nm and a solid content of 35%) was uniformly dispersed into 10000 mL of Tris-HCl solution to make its pH value 8.5. Then, 33.00 g of dopamine was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then, 81.56 g of tetraethylenepentamine (the molar ratio of dopamine to tetraethylenepentamine was 1:2) was added, and the reaction was continued to stir at room temperature for 6 h. Finally, the modified silica abrasive B15 was obtained by centrifugal filtration.

[0085] Modified silica abrasive B16:

[0086] 2000 g of silica sol A5 (silica particle size is 81 nm, solid content is 35%) was evenly dispersed into 10000 mL of Tris-HCl solution to make its pH value 8.5. Then 33.00 g of dopamine was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then 94.50 g of triethylenetetramine (the molar ratio of dopamine to triethylenetetramine is 1:3) was added, and the mixture was continuously stirred and reacted at room temperature for 6 h. Finally, the modified silica abrasive B16 was obtained by centrifugal filtration.

[0087] Modified silica abrasive B17:

[0088] 2000 g of silica sol A5 (silica particle size is 81 nm, solid content is 35%) was evenly dispersed into 10000 mL of Tris-HCl solution to make its pH value 8.5. Then 33.00 g of dopamine was added, and the mixture was stirred and reacted at a stirring speed of 40 rpm for 30 min. Then 163.12 g of tetraethylenepentamine (the molar ratio of dopamine to tetraethylenepentamine is 1:4) was added, and the mixture was continuously stirred and reacted at room temperature for 6 h. Finally, the modified silica abrasive B17 was obtained by centrifugal filtration.

[0089] Table 1 shows the average particle sizes of the silica abrasives before and after modification, and the particle size data was measured by a Malvern particle size analyzer.

[0090] Table 1

[0091]

[0092] It can be found from Table 1 that after the silica sol was modified, its average particle size was 3 - 10 nm larger than that before modification, thus proving that a modified layer was formed on the surface of the silica sol. Because polyphenols have oxidizing properties and are prone to polymerization with polyethylenepolyamines in a weakly alkaline solution to form a phenolic amine network structure layer. Adding polyphenols and polyethylenepolyamines to the alkaline solution containing silica sol can form an organic protective layer on the surface of silica sol particles.

[0093] Preparation steps of the polishing composition:

[0094] Table 2 shows the components and contents of the polishing compositions in Examples 1 - 19 and Comparative Examples 1 - 4 of the present invention. According to Table 2, the chemical mechanical polishing composition was prepared by simple stirring and mixing. Hydrogen peroxide was added before use and mixed evenly, and the balance was made up with water to obtain each example and comparative example of the present invention.

[0095] Table 2 Composition table of the polishing compositions of Examples 1 - 19 and Comparative Examples 1 - 4

[0096]

[0097] To verify the polishing effect of the polishing composition of the present invention, the polishing compositions of Examples 1 to 19 and Comparative Examples 1 to 4 were used to polish copper-containing materials respectively. The polishing conditions were as follows: the polishing machine was Ebara, the polishing pad was DH3002, the polishing pressure was 1.8 psi, the rotation speeds of the polishing head and the polishing disc were 93 / 87 rpm, the flow rate of the polishing composition was 300 mL / min, and the polishing time was 60 s.

[0098] The number of large particles (>0.56 μm) of the polishing composition was tested using an AccuSizer A7000 particle counter; the number of surface defects (>0.12 μm) of the blank wafer after polishing was detected using a surface defect scanner SP2, and the results of the number of surface defects obtained are listed in Table 3.

[0099] Table 3 Polishing effects of the polishing compositions of Examples 1 to 19 and Comparative Examples 1 to 4 of the present invention

[0100]

[0101] As can be seen from Table 3, in the polishing compositions of Comparative Examples 1 to 4, unmodified abrasives were used, and the maximum polishing rate for Cu was in the range of 6923 - 8108 defects on the surface of the wafer after polishing. After the abrasives in the polishing compositions of Examples 9 to 10 and 13 to 14 were modified, the polishing rate for Cu could be increased to At the same time, the number of surface defects was reduced to the range of 1179 - 1883, and the Defect (defects) was significantly improved.

[0102] As can be seen from Table 3, in the polishing compositions of Examples 1 to 4, the modified abrasives prepared using diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine respectively could maintain a relatively high polishing rate for Cu. However, for the modified abrasives prepared using triethylenetetramine or tetraethylenepentamine as the polyethylenepolyamine, the number of defects on the surface of the wafer after polishing was significantly reduced.

[0103] As can be seen from Table 3, in the polishing compositions of Examples 2 to 3 and Examples 5 to 8, the modified abrasives prepared using dopamine, catechol, catechin, gallic acid, and tannic acid respectively could maintain a relatively high polishing rate for Cu. However, for the modified abrasives prepared using dopamine or catechol as the polyphenol, the number of defects on the surface of the wafer after polishing was significantly reduced. In addition, for the modified abrasive prepared using dopamine as the polyphenol, its polishing effect was better than that of catechol.

[0104] As can be seen from Table 3, in the polishing compositions of Examples 11 to 14, when the average particle size of the modified silica abrasive was 33 - 166 nm, the polishing rate for Cu increased with the increase in particle size; but when the average particle size was 43 - 94, the number of surface defects after polishing was significantly reduced.

[0105] As can be seen from Table 3, in the polishing compositions of Examples 2-3 and 15-19, when the modified abrasive is prepared with a molar ratio of polyphenol to polyethylenepolyamine of 4:1 - 1:4, the polishing rate of Cu can be maintained at a relatively high level. However, when the molar ratio of polyphenol to polyethylenepolyamine is 3:1 - 1:2, the number of surface defects after polishing is reduced to the range of 950 - 1084, and the Defect is significantly improved.

[0106] In summary, the present invention uses an amino-containing polymer to coat and modify silica abrasive, so that the polishing composition has a relatively high removal rate for copper, and at the same time the surface defects after polishing are significantly improved.

[0107] Although the present invention has been described in detail above with general descriptions, specific embodiments and experiments, on the basis of the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of the present invention claimed.

Claims

1. A chemical mechanical polishing composition, characterized in that, The composition comprises a modified silica abrasive, a complexing agent, a corrosion inhibitor, a dispersant, an oxidizing agent and water; wherein, the modified silica abrasive has a core-shell structure, including a shell layer and a core layer, the core layer is silica sol, the shell layer is an amino-containing polymer, the amino-containing polymer is a polymerization product of polyphenol and polyethylenepolyamine, and the average particle size of the modified silica abrasive is 3-10 nm larger than the average particle size before modification; Wherein, the polyphenol is selected from at least one of dopamine, tannic acid, catechol, gallic acid, propyl gallate or catechin; the polyamine is selected from at least one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hydroxymethyldiethylenetriamine or hydroxyethyldiethylenetriamine.

2. A chemical mechanical polishing composition as described in claim 1, characterized in that, By mass percentage, the composition comprises 0.5%-3% of the modified silica abrasive, 5%-15% of the complexing agent, 0.02%-1.5% of the corrosion inhibitor, 0.01%-0.1% of the dispersant, 0.1%-3% of the oxidizing agent, and the balance is water.

3. A chemical mechanical polishing composition according to claim 1 or 2, characterized in that, The polyphenol is selected from one or more of dopamine, catechol, catechin, gallic acid and tannic acid.

4. A chemical mechanical polishing composition according to claim 1 or 2, characterized in that, The polyethylenepolyamine is selected from one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine.

5. A chemical mechanical polishing composition according to claim 1 or 2, characterized in that, The polyethylenepolyamine is preferably triethylenetetramine and / or tetraethylenepentamine.

6. A chemical mechanical polishing composition as described in claim 1 or 2, characterized in that, The polyphenol is selected from dopamine and / or catechol, and further preferably dopamine.

7. A chemical mechanical polishing composition according to claim 1 or 2, characterized in that, The molar dosage ratio of the polyphenol to the polyethylenepolyamine is 4:1-1:

4.

8. A chemical mechanical polishing composition as described in claim 1 or 2, characterized in that, The molar dosage ratio of the polyphenol to the polyethylenepolyamine is 3:1-1:2, preferably 3:1, 2:1, 1:1 or 1:

2.

9. The chemical mechanical polishing composition according to claim 1 or 2, characterized in that, The average particle size of the modified silica abrasive is 30-170 nm, preferably 40-100 nm, and further preferably 43-94 nm.

10. Use of the chemical mechanical polishing composition according to any one of claims 1-9 in copper chemical mechanical polishing.

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