WO2009006784A1

WO2009006784A1 - A modified silicon dioxide sol, the manufacturing method and use of the same

Info

Publication number: WO2009006784A1
Application number: PCT/CN2008/001259
Authority: WO
Inventors: Jery Guodong Chen; Peter Weihong Song; Daisy Ying Yao; Ephant Chengbing Song
Original assignee: Anji Microelectronics (Shanghai) Co., Ltd
Priority date: 2007-07-06
Filing date: 2008-07-01
Publication date: 2009-01-15
Also published as: CN101754929A; CN101338082A; CN101754929B

Abstract

The invention discloses a modified silicon dioxide sol, manufacturing method and use of the same, and a polishing liquid containing the same. The surface of the silicon dioxide of the modified silicon dioxide sol is bonded with epoxy-group-containing silane coupling agent. Modification is performed after mixing the silicon dioxide sol, surfactant and epoxy-group-containing silane coupling agent. Among the modified silicon dioxide sol according to the invention, surfaces of the silicon dioxide particles are grafted with epoxy groups, and on the one hand it can change hydrophilicity of the silicon dioxide particles, and on the other hand it can change the interaction between the silicon dioxide particles and the surfaces of wafer or polishing pad. Due to the improvement of the two properties, it can achieve higher polishing rates of TEOS and BD, and can bring less effect on polishing of Ta and Cu.

Description

Modified silica sol and preparation method and application thereof

The present invention relates to a modified silica sol, a process for its preparation, and its use in a polishing fluid. technical background

As the name implies, the polishing mechanism of the chemical mechanical polishing (CMP) polishing liquid on the semiconductor device is: The components in the polishing liquid remove the metal and non-metal in the semiconductor device by chemical mechanical action, thereby further flattening the effect. The CMP slurry consists of three main components: abrasives, chemicals, and dispersion media. Common dispersion media are water or alcohols such as ethanol, methanol, glycerin, and the like. Chemical reagents are the most important components in CMP polishing fluids. These chemicals can be classified into complexing agents (or rate enhancers), corrosion inhibitors, oxidants, surfactants, rheology modifiers, and pH adjustments. Agents, etc. Another important component of the CMP slurry is the abrasive, which are inorganic particles and organic polymer particles.

There are many types of abrasives used as CMP polishing fluids, mostly oxide particles or organic particles such as silica, alumina, zirconia, yttria, iron oxide, polystyrene granules and/or mixtures thereof. . These particles have different hardness and surface chemistry, which results in different polishing effects on the substrate of the semiconductor device, with alumina and silicon dioxide being the most used polishing abrasives.

Silica can be classified into fumed silica, precipitated silica, and silica sol according to the preparation method. The fumed silica and the precipitated silica are mostly aggregates of silica particles, and the products thereof are mostly silica powder. When these two kinds of silica are used in a CMP polishing liquid, they are often required. A lot of energy is needed to disperse the silica particles. Compared with the former two kinds of silica, the oxidized brick sol has the advantages of uniform dispersion, controllable particle size and more surface functional groups, and has gradually become a

The most important abrasive for CMP polishing fluids.

Most of the silica sol particles have a particle diameter of from 5 to 150 nm, and the dispersion medium is water, ethanol or other organic solvent. The surface of the silica particles is rich in hydroxyl groups, and the number of hydroxyl groups is 3-8#/nm ² . Therefore, the silica particles have strong hydrophilicity and polarity and can be stably dispersed in water. The hydroxyl group on the surface of the silica particles has strong activity, can generate ionization at a higher pH, and can also react with some chemicals.

Some chemical species react with the hydroxyl groups on the surface of the silica particles to change the surface chemistry of the silica particles. This treatment is called chemical modification of silica. The silane coupling agent is the most commonly used silica particle modifier, and its modification activity is high and the reaction conditions are mild. The silicon germanium coupling agent has a silicon oxyhydroxide group, which can undergo hydrolysis and polycondensation reaction with the hydroxyl group on the surface of the silica particle, thereby grafting the organic segment on the silicon coupling agent to the silica particle. Surface, changing the polarity of the surface of the silica particles.

The polishing slurry is specially treated to obtain a special polishing performance, and some patents have revealed this aspect of the research. For example, the patent document US Pat. No. 6,646,348 discloses a silicon germanium coupling agent as a component of a polishing liquid which is hydrolyzed to form an oligomer and is mixed with an abrasive and other chemical agents in the polishing liquid to obtain a lower The polishing rate of TEOS and Ta, and a better polished surface. Patent document US6656241 discloses a dichlorodimethylsilane-modified silica aggregate and is applied to a Cu polishing liquid, and the silica aggregate is modified to be well dispersed in the polishing liquid, and Cu The polishing rate and selectivity of Ta and Ta are affected by the modification treatment. US Pat. No. 6,582,623 discloses a polishing slurry for modifying abrasives, dispersing the silane coupling agent directly with the abrasive. The body phase is mixed and then configured as a polishing liquid, which can be applied to various wafer surfaces such as polishing ^, Cu, etc.

SUMMARY OF THE INVENTION An object of the present invention is to disclose a modified disilica sol which is capable of exerting a significant influence on the polishing performance of a polishing liquid.

In the modified silica sol of the present invention, an epoxy group-containing silane coupling agent is bonded to the surface of the silica. The epoxy group-containing silicon germanium coupling agent may be selected from the group consisting of Y-glycidoxypropyltrimethoxysilane, hydrazine-glycidoxypropyldimethoxysilane, Y-shrinkage Glycidoxypropyltriethoxysilane, Y-glycidoxypropyldiethoxysilane or Y-glycidoxypropylchlorosilane, etc., preferably Y-glycidoxypropyl Trimethoxysilane.

In the present invention, the modified silica sol preferably has a particle diameter of 10 to 500 nm, more preferably 10 to 150 nm.

Another object of the present invention is to disclose a method for preparing a modified silica sol of the present invention, which comprises the steps of: mixing a silica sol, a surfactant, and a silane coupling agent containing an epoxy group; After that, the modification reaction can be carried out.

In the method of the present invention, the epoxy group-containing silane coupling agent may be selected from the group consisting of Y-glycidoxypropyltrimethoxysilane and Y-glycidoxypropyldimethoxysilane. Yttrium, Y-glycidoxypropyltriethoxysilane, _Y -glycidoxypropyldiethoxysilane or hydrazine-glycidoxypropylsilane, preferably hydrazine - glycidoxypropyltrimethoxysilane. The epoxy group-containing silicon germanium coupling agent is preferably used in an amount of from 0.02 to 1% by mass, more preferably from 0.2 to 0.5% by mass based on the mass% of the silica sol.

In the method of the present invention, a surfactant is further added to the reactant for the purpose of improving the modifier Dispersibility in water and compatibility with silica sol particles. The surfactant may be selected from the group consisting of anionic surfactants, cationic surfactants, nonionic surfactants, and zwitterionic surfactants. Among them, polyacrylic acid, polyethylene glycol, betaine or dodecyl ammonium bromide is preferred. The surfactant is preferably used in an amount of 0.01 to 1% by mass based on the total amount of the reactants, more preferably 0.01 to 0.1% by mass.

In the method of the present invention, the modification temperature may generally be from 20 ° C to 100 ° C, preferably from 20 to 70 ° C; the modification time may generally be from 1 hour to 24 hours, or even longer, to facilitate The reaction is carried out sufficiently, preferably 2 to 24 hours, more preferably 2 to 7 hours; the pH environment of the reaction may generally be 1 to 14, preferably 2 to 12, more preferably 7 to 12, Under alkaline conditions, it is more conducive to solving the problem that silica is easy to gel. In the modification process, hydrochloric acid, nitric acid, sulfuric acid, sodium hydroxide, potassium hydroxide, ammonia water, organic amine, etc. are generally used to adjust the pH of the solution. A small amount of water can be added during the preparation.

A further object of the invention is to disclose a polishing fluid comprising the modified silica sol of the invention. After the surface of the silica particles is modified by the above method using a silicon germanium modifier containing an epoxy group, the hydrophilicity of the surface of the silica particles can be changed. Moreover, the grafting of the epoxy groups on the surface of the silica particles can change the interaction between the silica particles and the surface of the wafer and the polishing pad, thereby affecting the final properties of the polishing liquid. The polishing liquid may contain other conventional additives in the art.

The reagents and starting materials used in the present invention are commercially available.

The positive progress of the present invention is as follows: In the modified silica sol of the present invention, the surface of the silica particles is grafted with an epoxy group, which changes the hydrophilicity of the silica particles on the one hand, and changes on the other hand. The interaction of silica particles with the surface of the wafer and polishing pad. Based on the above two performance improvements, the CMP polishing solution prepared by using the modified silica described in this patent can have a higher polishing rate of TEOS and BD, and has little effect on the polishing of Ta and Cu. DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a polishing rate of BD, TEOS, Ta and Cu in polishing liquids 1 to 3 and comparative polishing liquids 1 to 3 containing modified silica having different particle diameters in Example 1.

Figure 2 shows the polishing rates of BD, TEOS, Ta and Cu in the polishing solution 4~5 and the comparative polishing solution 4~5 in Example 2.

Fig. 3 is a polishing rate of BD, TEOS, Ta and Cu in the polishing liquid 6~9 of the modified silica prepared by modifying the silicon dioxide modified by different amounts of silicon germanium modifier in the third embodiment.

Fig. 4 is a polishing rate of 10 to 12 pairs of BD, TEOS, Ta and Cu in the polishing liquid containing the modified silica prepared at different temperatures in Example 4.

Fig. 5 is a polishing rate of BD, TEOS, Ta and Cu in the polishing liquid 13-15 of the modified silica prepared in Example 5 in the same reaction time.

Fig. 6 is a polishing rate of BD, TEOS, Ta and Cu in the polishing liquids 16 to 18 of the modified silica prepared in Example 6 containing the modified silica.

Fig. 7 is a polishing rate of BD, TEOS, Ta and Cu for polishing liquids 19 to 23 and comparative polishing liquids 6 to 10 containing modified silica prepared by adding different surfactants in Example 7.

Fig. 8 is a polishing rate of BD, TEOS, Ta and Cu in the polishing liquid of 24 to 27 containing the modified silica prepared by using a surfactant in different amounts in Example 8. Summary of the invention

The invention is further illustrated by the following examples, which are not intended to limit the invention. In the following examples, the percentage of content refers to the mass percentage unless otherwise specified.

Method embodiment 1

Silica sol (30% solids, particle size 10 nm) 94.7%, Y-glycidoxypropyltrimethoxysilane (0.1% silica sol), betaine amphoteric surfactant (dosage) It is 0.05% of the total amount of the reactants, and the balance is water. After the above mixture was adjusted with a 50% KOH solution, pH=12, and the reaction was stirred at 20 ° C for 24 hours to obtain a modified silica sol.

Silica sol (30% solids, particle size 50nm) 94.7%, Y-glycidoxypropyltrimethoxysilane (0.2% by weight of silica sol), betaine amphoteric surfactant (dosage It is 0.5% of the total amount of the reactants, and the balance is water. The mixture was adjusted to pH = 10 with a 50% KOH solution, and the reaction was stirred at 40 ° C for 6 hours to obtain a modified silica sol (50 nm). Method embodiment 3

Silica sol (30% solids, particle size 100 nm) 94.7%, Y-glycidoxypropyltrimethoxysilane (0.02% silica sol), polyacrylic acid surfactant (amount 1% of the total amount of the reactants, the balance being water. The mixture was adjusted to pH = 2 with a 50% KOH solution, and the reaction was stirred at 50 ° C for 7 hours to obtain a modified silica sol (100 nm). Method embodiment 4

Silica sol (30% solids, particle size 150nm) 94.7%, Y-glycidoxypropyltrimethoxysilane (1% by weight of silica sol), polyethylene glycol surfactant ( The amount is 0.1% of the total amount of the reactants, and the balance is water. After the mixture was adjusted to pH = 7 with a 50% KOH solution, the reaction was stirred at 70 ° C for 2 hours to obtain a modified silica sol (150 nm). Method embodiment 5

Silica sol (30% solids, particle size 500 nm) 94.7%, Y-glycidoxypropyltrimethoxysilane (0.5% by weight of silica sol), Twisted iodide ammonium bromide surface active The agent (in an amount of 0.01% of the total amount of the reactants), the balance being water. After the mixture was adjusted to pH = 9, the reaction was stirred at 30 ° C for 10 hours to obtain a modified silica sol (500 nm).

In the following examples, A187 is Y-glycidoxypropyltrimethoxysilane, and CAB-30 is a betaine amphoteric surfactant.

Effect embodiment 1

Comparative polishing solution 1: silica (10 nm) sol particles 7.0%, BTA O.1%, H ₂ Q ₂ 0.03%, tartaric acid, polyacrylic acid anionic surfactant (BIK Chemical Co., Ltd.) Water is the balance, pH= 3

Comparative polishing solution 2: silica (90 nm) sol particles 7.0%, BTA O.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, water is The balance, pH = 3.0.

Polishing solution 1: A187 modified silica (10 nm) sol particles 7.0 ° /. , BTA O.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, water is the balance, pH=3.0.

Polishing solution 2: A187 modified silica (90 nm) sol particles 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, water is Balance, pH=3.0.

Polishing conditions: polishing pressure 2.0 psi, polishing disk speed 70 rpm, polishing fluid flow rate 100 ml/min, polishing pad Politex, Logitech PM5 Polisher The polishing performance of the comparative polishing liquid 1 to 2 and the polishing liquid 1 to 2 is as shown in Fig. 1. As can be seen from the figure, the polishing liquid containing the modified silica particles has a high polishing rate of TEOS and BD. Especially when the silica particles are small (10 nm), the polishing rate of TEOS and BD is remarkably improved after the surface modification treatment. Effect Example 2

Polishing solution 3: A187 modified silica (20 nm) sol particles 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, water is Balance, pH=3.0.

Comparative polishing solution 3: silica (20 nm) sol particles 7.0%, A187 and CAB-30 reaction mixture 2.46%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (Bick Chemical company) 0.05%, water is the balance, pH=3.0. The preparation method of A187 and CAB-30 reaction mixture is: 2% A187, l%CAB-20, the balance is water, the solution is at 40 ° C, pH The reaction was stirred for 6 hours at =10.

Polishing solution 4: A187 modified silica (20 nm) sol type 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, alcoholic acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, Water is the balance, pH=3.0.

Comparative polishing solution 4: silica (20 nm) sol particles 7.0%, A187 reactant 2.46%, BTA 0.1%, H ₂ O ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05 %, water is the balance, pH=3.,0. The preparation method of A187 reactant is: 2% A187, the balance is water, and the solution is stirred at 40 ° C, pH = 10 for 6 hours.

Polishing conditions: polishing pressure 2.0 psi, polishing disk speed 70 rpm, polishing liquid flow rate 100 ml/min, polishing pad Politex, Logitech PM5 Polisher. The polishing performance of the comparative polishing liquid 3, 4 and the polishing liquid 3, 4 is shown in Fig. 2. As can be seen from the figure, the polishing liquid containing the silicon silicate modifier A187 modified silica sol has a higher polishing rate of BD and TEOS. Effect Example 3

Polishing solution 5: 0.02% A187 modified silica (20 nm) Sol particles 7.0%, BTA 0.1%, 3⁄40 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, water For the balance, pH=3.0.

Polishing solution 6: 0.2% A187 modified silica (20 nm) Sol particles 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05% , water is the balance, - ρΗ=3.Ό.

Polishing solution 7: 0.5% A187 modified silica (20 nm) Sol particles 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05 %, water is the margin, ρΗ=3·0.

Polishing conditions: polishing pressure 2.0 psi, polishing disk speed 70 rpm, polishing fluid flow rate 100 ml/min, polishing pad Politex, Logitech PM5 Polisher.

: The polishing performance of the polishing solution 5~7 is shown in Figure 3. As can be seen from the figure, in the preparation method, the use of different modifiers, especially 0.2% to 0.5%, gives the modified silica a higher polishing rate of TEOS and BD. Effect Example 4

Polishing solution 8: A187 modified silica (20 nm) sol particles at 20 ° C 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, water is the balance, pH=3.0.

Polishing solution 9: A187 modified silica (20 nm) sol particles 7.0% at 40 ° C, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, water is the balance, pH=3.0.

Polishing solution 10: A187 modified silica (20 nm) sol particles 7.0% at 70 ° C, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, water is the balance, pH=3.0.

The polishing performance of the polishing solution 8~10 is shown in Figure 4. As can be seen from the figure, the polishing solutions containing silica modified at different reaction temperatures have higher TEOS and BD polishing rates. Effect Example 5

Polishing solution 11: Silica (20 nm) sol particles modified under reaction for 2 hours 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BIK Chemical Co., Ltd.) 0.05 %, water is the balance, pH=3.0.

Polishing solution 12: Silica (20 nm) sol particles modified at 4 hours under reaction for 4 hours, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) %, water is the balance, pH=3.0.

Polishing solution 13: Silica (20 nm) sol particles modified at 7 hours under reaction for 7 hours, BTA 0.1%, 3⁄40 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, water is the balance, pH=3.0.

The polishing performance of the polishing liquid 11~13 is shown in Fig. 5. As can be seen from the figure, modified silica polishing fluids prepared with different reaction times have higher TEOS and BD polishing rates. Effect Example 6

Polishing solution 14: Modified silica (20 nm) sol particles 7.0% at pH=2, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) %, water is the balance, pH=3.0.

Polishing solution 15: modified silica (20 nm) sol particles 7.0% at pH=7, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polypropylene 'ene' acid anionic surfactant (BYK Chemical Company) 0.05%, water is the balance, pH=3.0.

'Polishing liquid 16: Modified silica (20 nm) sol particles 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, water is the balance, pH=3.0.

The polishing performance of the polishing liquid 14 to 16 is shown in Fig. 6. It can be seen from the figure that the modified silica prepared by the modification reaction at different pH values, especially above pH 7, makes the polishing liquid have a higher polishing rate of TEOS and BD. Effect Example 7

Slurry 17: Surfactant is betaine amphoteric surfactant CAB-30 modified silica (20nm) Sol particles 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anion Surfactant (BYK Chemical Co., Ltd.) 0.05%, water is the balance, pH=3.0.

Comparative polishing solution 5: silica (20 nm) sol particles 7.0%, BTA 0.1%, H ₂ O ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, CAB-30 240 ppm , water is the balance, pH=3.0.

Polishing solution 18: Surfactant is anionic surfactant Polyacrylic acid modified silica (20 nm) Sol particles 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surface activity Agent (Bick Chemical Company) 0.05%, water is the balance, pH=3.0.

Comparative Polishing Solution 6: Silica (20 nm) sol particles 7.0°/. , BTA 0.1%, H ₂ O ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.074%, water is the balance, pH=3.0.

Polishing solution 19: Surfactant is anionic surfactant Dodecylbenzenesulfonic acid modified silica (20 nm) Sol particles 7.0° / ₀ , BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2% , Polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.074%, water is the balance, pH=3.0. Comparative polishing solution 7: silica (20nm) sol particles 7.0%, BTA 0.1%, H ₂ O ₂ 0.03 %, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, benzenesulfonic acid 240ppm, water as the balance, pH=3.0.

Polishing solution 20: The surfactant is a nonionic surfactant polyethylene glycol (PEG200) modified silica (20 nm) sol particles 7.0%, BTA 0.1%, H ₂ O ₂ 0.03%, tartaric acid 0.2% , polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.074%, water is the balance, pH=3.0.

Comparative polishing solution 8: silica (20 nm) sol particles 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, PEG200 240 ppm, water For the balance, pH=3.0.

Polishing solution 21: Surfactant is a cationic surfactant, dodecyl ammonium bromide (CTAB) modified silica (20 nm) sol particles 7.0%, BTA 0.1%, H ₂ O ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.074%, water is the balance, pH=3.0.

Comparative polishing solution 9: silica (20 nm) sol particles 7.0%, BTA 0.1%, H ₂ O ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd.) 0.05%, CTAB 240 ppm, water For the balance, pH=3.0.

Polishing conditions: polishing pressure 2.0 psi, polishing disk speed 70 rpm, polishing fluid flow rate 100 ml/inin, polishing pad Politex, Logitech PM5 Polisher.

The polishing performance of the polishing liquid 17 to 21 and the comparative polishing liquid 6 to 10 is shown in Fig. 7. It can be seen from the figure that different surfactants are used in the modification process, and the modified silica has different polishing performance surfaces. However, the polishing liquid containing the modified silica always exhibits a higher TEOS and BD polishing rate than the unmodified silica. Effect Example 8

Polishing solution 22: 0.01% CAB-30 modified silica (20nm) sol particles 7.0%, BTA 0.1%, H ₂ O ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd. ) 0.05%, water is the balance, pH = 3.0. Polishing solution 23: 0.10% CAB-30 modified silica (20 nm) sol particles 7.0%, BTA 0.1%, H ₂ O ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd. ) 0.05%, water is the balance, pH = 3.0.

Polishing solution 24: 0.30% CAB-30 modified silica (20 nm) sol particles 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd. ) 0.05 ° /. , water is the balance, pH=3.0.

Polishing solution 25: 0.50% CAB-30 modified silica (20 nm) sol particles 7.0%, BTA 0.1%, H ₂ 0 ₂ 0.03%, tartaric acid 0.2%, polyacrylic acid anionic surfactant (BYK Chemical Co., Ltd. ) 0.05%, water is the balance, pH = 3.0.

Polishing conditions: polishing pressure 2.0 psi, polishing disk speed 70 rpm, polishing fluid flow rate 100 ml/min, polishing pad Politex, Logitech PM5 Polisher

The polishing performance of the polishing solution 22~25 is shown in Fig. 8. It can be seen from the figure that different amounts of strontium are used in the modification process, especially 0.01-0.1% of the surfactant, and the modified silica obtained can make the polishing liquid have higher BD and TEOS polishing rate. .

Claims

Rights request

A modified silica sol characterized in that a silica-containing silane coupling agent is bonded to the surface of the silica.

The modified silica sol according to claim 1, wherein the epoxy group-containing silane coupling agent is Y-glycidoxypropyltrimethoxysilane.

The modified silica sol according to claim 1, wherein the modified silica sol has a particle diameter of 10 to 500 nm.

The modified silica sol according to claim 3, wherein the modified silica sol has a particle diameter of 10 to 150 nm.

The method for producing a modified silica sol according to claim 1, wherein the silica sol, the surfactant, and the silane coupling agent containing an epoxy group are mixed and then carried out The modification reaction can be carried out.

6. The method according to claim 5, wherein the epoxy group-containing silane coupling agent is Y-glycidoxypropyltrimethoxysilane.

7. The method according to claim 5, wherein the epoxy group-containing silicon germanium coupling agent is used in an amount of 0.02 to 1% by mass of the silica sol.

8. The method according to claim 7, wherein: the epoxy group-containing silicon germanium coupling agent is used in an amount of 0.2 to 0.5% by mass of the silica sol.

9. The method of claim 5 wherein: the surfactant is an anionic surfactant, a cationic surfactant, a nonionic surfactant, and a zwitterionic surfactant.

10. The method of claim 9 wherein: said surfactant is polyacrylic acid, Polyethylene glycol, betaine or dodecyl ammonium bromide.

The method according to claim 5, wherein the surfactant is used in an amount of 0.01 to 1% by mass based on the total amount of the reactant.

The method according to claim 11, wherein the surfactant is used in an amount of 0.01 to 0.1% by mass based on the total amount of the reactants.

The method according to claim 5, wherein the temperature of the modification reaction is 20 to 70 °C.

The method according to claim 5, wherein the modification reaction takes 2 to 24 hours.

The method according to claim 14, wherein the modification reaction takes 2 to 7 hours.

The method according to claim 5, wherein the modifying reaction is carried out in an environment having a pH of 2 to 12.

1.7. The method according to claim 16, wherein: the modifying reaction is carried out in an environment having a pH of from 7 to 12.

18. A polishing liquid comprising the modified silica sol of claim 1.