A chemical mechanical polishing liquid and its preparation method and application

Abstract

The invention discloses a chemical mechanical polishing liquid, comprising an adrenaline compound, wherein the molecular structure of the adrenaline compound is: , wherein R1 is x, y-benzene or x, y, z-benzene, wherein x, y, z are numbers from 2 to 6; R2 and R3 are hydrogen atoms, alkanes with carbon numbers of 1 to 6, or alcohols with carbon numbers of 1 to 6; and n is a number from 1 to 3. The invention provides a chemical mechanical polishing liquid, a preparation method thereof, and an application thereof, which can improve the polishing rate of the polishing liquid on a silicon dioxide dielectric layer while suppressing the polishing rate of silicon nitride, and can avoid or reduce the generation of dishing grooves and scratch defects during the polishing process.

Description

Technical Field

[0001] The invention relates to the technical field of polishing liquid, and in particular to a chemical mechanical polishing liquid and a preparation method and application thereof. Background Art

[0002] Shallow trench isolation (STI) is the main method for device isolation in IC manufacturing. In STI technology, the first step is to generate several grooves at predetermined positions on the substrate, usually using anisotropic etching. Secondly, silicon dioxide is deposited in each groove, and then the silicon dioxide is polished by CMP. The STI structure is formed by polishing down to the silicon nitride layer. The polishing of STI requires not only a very high HDP oxide (silicon dioxide) removal rate and a very high selectivity for silicon nitride, but also a very low surface defect index and polishing uniformity of different density areas, because this directly determines the efficiency of device isolation.

[0003] Cerium oxide is an important abrasive particle for CMP polishing liquid. Compared with traditional silica sol abrasive particles, cerium oxide has more efficient polishing characteristics for silicon dioxide materials and has been widely used in CMP polishing of STI and ILD. Traditional cerium oxide abrasive particles used for CMP polishing are prepared by high-temperature calcination and ball milling dispersion. As the technology nodes of integrated circuits develop towards smaller sizes, lower polishing defect requirements are put forward for the CMP polishing process. The cerium oxide synthesized by traditional high-temperature calcination has multi-angular particles, and micro scratches are inevitably generated during the CMP polishing process. It is difficult to meet the CMP polishing requirements of advanced processes. Sol-gel cerium oxide abrasive particles have a nearly round particle morphology, showing good prospects for CMP polishing applications, and are receiving more and more attention.

[0004] However, in the CMP polishing application of STI, it is usually required to have a high polishing rate of the silicon dioxide dielectric layer and a low polishing rate of the silicon nitride dielectric layer, and it is best that the polishing rate of the silicon nitride dielectric layer can be close to zero. In other words, a high selectivity of silicon dioxide to silicon nitride is required. Therefore, how to provide a new formula of sol-gel type CMP polishing liquid, which can significantly improve the polishing rate of sol-gel cerium oxide particles to silicon dioxide while suppressing its polishing rate to silicon nitride without causing other polishing defects, is a problem that needs to be solved in this industry. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a chemical mechanical polishing liquid and a preparation method and application thereof, which can improve the polishing rate of the polishing liquid on the silicon dioxide dielectric layer while suppressing the polishing rate of silicon nitride, and can avoid or reduce the generation of dishing grooves and scratch defects during the polishing process.

[0006] To achieve the above object, the embodiment of the present invention adopts the following technical solution: a chemical mechanical polishing liquid, comprising an adrenaline compound, the molecular structure of the adrenaline compound is: , wherein R1 is x,y-benzenediol or x,y,z-benzenetriol, wherein x, y, z are numbers from 2 to 6; R2 and R3 are hydrogen atoms, alkanes with carbon numbers of 1 to 6, or alcohols with carbon numbers of 1 to 6; and n is a number from 1 to 3.

[0007] According to one aspect of the present invention, the alcohol having 1 to 6 carbon atoms is a primary alkanol having 1 to 6 carbon atoms.

[0008] According to one aspect of the present invention, it further comprises abrasive particles, organic high molecular polymer and organic polyacid.

[0009] According to one aspect of the present invention, the mass percentage of the adrenaline compound is 0.005%-0.8%.

[0010] According to one aspect of the present invention, the mass percentage of the organic high molecular polymer is 0.05%-1%.

[0011] According to one aspect of the present invention, the mass percentage of the abrasive particles is 0.5%-10%.

[0012] According to one aspect of the present invention, the mass percentage of the organic polyacid is 0.1%-1.3%.

[0013] According to one aspect of the present invention, the adrenaline compounds include but are not limited to the following optical isomers and mixtures thereof: R configuration, S configuration, and racemic configuration.

[0014] According to one aspect of the present invention, the adrenaline compound can be R-adrenaline; S-adrenaline; R-norepinephrine; S-norepinephrine; 4-(2-dimethylamino-1-hydroxyethyl)-1,2-benzenediol; 4-(2-dihydroxymethylamino-1-hydroxyethyl)-1,2-benzenediol; 4-(2-dihydroxyethylamino-1-hydroxyethyl)-1,2-benzenediol; 4-(2-dimethylamino-1-hydroxyethyl)-1,2,3-benzenetriol; 4-(2-dihydroxymethylamino-1-hydroxyethyl) -1,2,3-benzenetriol; 4-(2-dihydroxyethylamino-1-hydroxyethyl)-1,2,3-benzenetriol; 6-(2-dimethylamino-1-hydroxyethyl)-1,2,4-benzenetriol; 6-(2-dihydroxymethylamino-1-hydroxyethyl)-1,2,4-benzenetriol; 6-(2-dihydroxyethylamino-1-hydroxyethyl)-1,2,4-benzenetriol; 4-(2-dimethylamino-1-hydroxyethyl)-1,3-benzenetriol; 4-(2-dihydroxymethylamino-1-hydroxyethyl)-1,3-benzenetriol; 4- (2-dihydroxyethylamino-1-hydroxyethyl)-1,3-benzenediol; 5-(2-dimethylamino-1-hydroxyethyl)-1,4-benzenediol; 5-(2-dihydroxymethylamino-1-hydroxyethyl)-1,4-benzenediol; 5-(2-dihydroxyethylamino-1-hydroxyethyl)-1,4-benzenediol; 6-(2-dimethylamino-1-hydroxyethyl)-1,2,5-benzenediol; 6-(2-dihydroxymethylamino-1-hydroxyethyl)-1,2,5-benzenediol; 6-(2-dihydroxyethylamino-1-hydroxyethyl)- 1,2,5-benzenetriol; 6-(2-dimethylamino-1-hydroxyethyl)-1,3,5-benzenetriol; 6-(2-dihydroxymethylamino-1-hydroxyethyl)-1,3,5-benzenetriol; 6-(2-dihydroxyethylamino-1-hydroxyethyl)-1,3,5-benzenetriol; 5-(2-dimethylamino-1-hydroxyethyl)-1,2,3-benzenetriol; 5-(2-dihydroxymethylamino-1-hydroxyethyl)-1,2,3-benzenetriol; 5-(2-dihydroxyethylamino-1-hydroxyethyl)-1,2,3-benzenetriol.

[0015] According to one aspect of the present invention, the organic high molecular polymer is one or more of polyacrylic acid and its salts, polyvinyl pyrrolidone and / or polyethylene glycol. The molecular weight of the polyacrylic acid and its salts is 3000-5000. The molecular weight of the polyvinyl pyrrolidone is 3000-10000. The molecular weight of the polyethylene glycol is 3000-5000.

[0016] According to one aspect of the present invention, the abrasive particles are sol-gel cerium oxide, and the average particle size of the cerium oxide is 50-300 nanometers, and the average grain size is 20-150 nanometers.

[0017] According to one aspect of the present invention, the organic polyacid is one or more of acetic acid, glycine, citric acid, iminodiacetic acid, malonic acid and / or succinic acid.

[0018] According to one aspect of the present invention, the invention further comprises water and a pH regulator, wherein the pH regulator is ammonia water or nitric acid.

[0019] According to one aspect of the present invention, an antimicrobial agent and a viscosity regulator are also included.

[0020] According to one aspect of the present invention, the method for preparing the chemical mechanical polishing solution comprises the following steps:

[0021] Configure the required components;

[0022] Mix all ingredients well.

[0023] According to one aspect of the present invention, the chemical mechanical polishing liquid is used in the polishing process of silicon dioxide and silicon nitride.

[0024] Advantages of the present invention: The chemical mechanical polishing liquid, by adding adrenaline compounds, can effectively suppress the polishing rate of silicon nitride while increasing the polishing rate of the polishing liquid on the silicon dioxide dielectric layer, thereby increasing the polishing selectivity of silicon dioxide / silicon nitride. By adding adrenaline compounds, the occurrence of defects such as dents and scratches during the polishing process can also be reduced or avoided. Adrenaline compounds, organic high molecular polymers and organic polyacids work together to form a stable polishing liquid by adjusting the content of each substance, which can make the polishing selectivity of silicon dioxide / silicon nitride greater than 30, and effectively avoid or reduce the occurrence of defects such as dents and scratches during the polishing process. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] A chemical mechanical polishing liquid comprises an adrenaline compound, wherein the molecular structure of the adrenaline compound is: , wherein R1 is x,y-benzenediol or x,y,z-benzenetriol, wherein x, y, z are numbers from 2 to 6; R2 and R3 are hydrogen atoms, alkanes with carbon numbers of 1 to 6, or alcohols with carbon numbers of 1 to 6; and n is a number from 1 to 3.

[0027] In practical applications, the alcohol having 1 to 6 carbon atoms is preferably a primary alkanol having 1 to 6 carbon atoms.

[0028] In practical applications, abrasive particles, organic high molecular polymers and organic polyacids are also included.

[0029] In practical applications, the mass percentage of the adrenaline compound is 0.005%-0.8%.

[0030] The mass percentage of the organic high molecular polymer is 0.05%-1%. The mass percentage of the abrasive particles is 0.5%-10%. The mass percentage of the organic polyacid is 0.1%-1.0%.

[0031] In practical applications, the adrenaline compounds include but are not limited to the following optical isomers and mixtures thereof, R configuration, S configuration, and racemic configuration. Specifically, the adrenaline compounds may be R-adrenaline; S-adrenaline; R-norepinephrine; S-norepinephrine; 4-(2-dimethylamino-1-hydroxyethyl)-1,2-benzenediol; 4-(2-dihydroxymethylamino-1-hydroxyethyl)-1,2-benzenediol; 4-(2-dihydroxyethylamino-1-hydroxyethyl)-1,2-benzenediol; 4-(2-dimethylamino-1-hydroxyethyl)-1,2,3-benzenetriol; 4-(2-dihydroxymethylamino-1-hydroxyethyl)-1,2, 3-benzenetriol; 4-(2-dihydroxyethylamino-1-hydroxyethyl)-1,2,3-benzenetriol; 6-(2-dimethylamino-1-hydroxyethyl)-1,2,4-benzenetriol; 6-(2-dihydroxymethylamino-1-hydroxyethyl)-1,2,4-benzenetriol; 6-(2-dihydroxyethylamino-1-hydroxyethyl)-1,2,4-benzenetriol; 4-(2-dimethylamino-1-hydroxyethyl)-1,3-benzenetriol; 4-(2-dihydroxymethylamino-1-hydroxyethyl)-1,3-benzenetriol; 4-(2-dihydroxymethylamino-1-hydroxyethyl)-1,3-benzenetriol 5-(2-dimethylamino-1-hydroxyethyl)-1,3-benzenediol; 5-(2-dimethylamino-1-hydroxyethyl)-1,4-benzenediol; 5-(2-dihydroxymethylamino-1-hydroxyethyl)-1,4-benzenediol; 5-(2-dihydroxyethylamino-1-hydroxyethyl)-1,4-benzenediol; 6-(2-dimethylamino-1-hydroxyethyl)-1,2,5-benzenediol; 6-(2-dihydroxymethylamino-1-hydroxyethyl)-1,2,5-benzenediol; 6-(2-dihydroxyethylamino-1-hydroxyethyl)-1, 2,5-benzenetriol; 6-(2-dimethylamino-1-hydroxyethyl)-1,3,5-benzenetriol; 6-(2-dihydroxymethylamino-1-hydroxyethyl)-1,3,5-benzenetriol; 6-(2-dihydroxyethylamino-1-hydroxyethyl)-1,3,5-benzenetriol; 5-(2-dimethylamino-1-hydroxyethyl)-1,2,3-benzenetriol; 5-(2-dihydroxymethylamino-1-hydroxyethyl)-1,2,3-benzenetriol; 5-(2-dihydroxyethylamino-1-hydroxyethyl)-1,2,3-benzenetriol.

[0032] In practical applications, the organic high molecular polymer is one or more of polyacrylic acid and its salts, polyvinyl pyrrolidone and / or polyethylene glycol. The molecular weight of the polyacrylic acid and its salts is 3000-5000. The molecular weight of the polyvinyl pyrrolidone is 3000-10000. The molecular weight of the polyethylene glycol is 3000-5000.

[0033] In practical applications, the abrasive particles can be abrasive particles commonly used in the art, such as one or more of silicon dioxide, aluminum oxide, cerium dioxide, and titanium dioxide abrasive particles. Preferably, the abrasive particles are preferably sol-gel cerium oxide. The average particle size of the sol-gel cerium oxide is 50-300 nanometers, and the average grain size is 20-150 nanometers.

[0034] In practical applications, the organic polyacid is one or more of acetic acid, glycine, citric acid, iminodiacetic acid, malonic acid and / or succinic acid.

[0035] In practical applications, water and a pH adjuster are also included. The pH adjuster is ammonia water or nitric acid. Preferably, the pH value of the polishing liquid is adjusted to 3.5-9 by the pH adjuster.

[0036] In practical applications, the chemical mechanical polishing liquid further comprises an antibacterial agent and a viscosity regulator. Specifically, the antibacterial agent and the viscosity regulator can be selected from conventional antibacterial agent and viscosity regulator products on the market.

[0037] In practical applications, the chemical mechanical polishing liquid, by adding adrenaline compounds, can effectively suppress the polishing rate of silicon nitride while increasing the polishing rate of the polishing liquid on the silicon dioxide dielectric layer, thereby improving the polishing selectivity of silicon dioxide / silicon nitride. By adding adrenaline compounds, the occurrence of defects such as dents and scratches during the polishing process can also be reduced or avoided. Adrenaline compounds, organic high molecular polymers and organic polyacids work together to form a stable polishing liquid by adjusting the content of each substance, which can make the polishing selectivity of silicon dioxide / silicon nitride greater than 30, and effectively avoid or reduce the occurrence of defects such as dents and scratches during the polishing process.

[0038] In practical applications, the preparation method of the chemical mechanical polishing solution comprises the following steps:

[0039] Configure the required components;

[0040] Mix all ingredients well.

[0041] In practical applications, the chemical mechanical polishing liquid is used in the polishing process of silicon dioxide and silicon nitride.

[0042] The advantages of the present invention are further described below through more specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0043] Table 1 shows the formulas of Examples 1 to 12 and Comparative Examples 1 to 6 of the chemical mechanical polishing solution of the present invention.

[0044] Among them: the reagents and raw materials used are commercially available. The particle size of the cerium oxide particles used is the average equivalent diameter, and the average particle size is measured by a Nano-ZS90 laser particle size analyzer of Malvern Company; the grain size of the cerium oxide particles used in the polishing liquid is measured by a Shimadzu LabX XRD-6100 X-ray diffractometer of Japan.

[0045] First, cerium oxide particles are added to a set concentration of organic polymer solution and mixed evenly to obtain abrasive particle dispersion. Then, components other than abrasive particles and organic polymer are mixed evenly in deionized water according to the contents listed in Table 1, and the pH value is adjusted to the required value with ammonia water (NH4OH). Then, the abrasive particle dispersion dispersed with the organic polymer is added. If the pH value drops, ammonia water (NH4OH) is used to adjust the pH value to the required value, and deionized water is used to make up the percentage to 100wt%, and each chemical mechanical polishing liquid can be obtained.

[0046] Table 1

[0047]

[0048]

[0049]

[0050] In order to verify the use effect of the chemical mechanical polishing liquid of the present invention, effect verification example 1 is set up for illustration.

[0051] Effect verification example 1:

[0052] The polishing liquids of Examples 1 to 6 of the present invention and the polishing liquids of Comparative Examples 1 to 6 were used to perform chemical mechanical polishing experiments on blank silicon dioxide (Teos) and Si3N4. The polishing conditions used were: using a Logitech polishing pad, a downward pressure of 3psi, a turntable speed / polishing head speed = 60 / 80rpm, a polishing time of 60s, and a chemical mechanical polishing liquid flow rate of 100mL / min. Among them, the wafer slices used for polishing are all sliced ​​from commercially available 8-inch coated wafers (for example, produced by SVTC, USA). The thickness of silicon dioxide (Teos) and Si3N4 was measured by a NANO SPEC6100 tester produced by Matrics. The removal rate of silicon dioxide (Teos) and Si3N4, the scratch evaluation of silicon dioxide (Teos) and the evaluation of the dishing defect were performed respectively.

[0053] Specifically, the thickness difference measured before and after polishing was divided by the polishing time to obtain the removal rate values ​​of silicon dioxide (Teos) and Si3N4, and the selectivity of silicon dioxide (Teos) to Si3N4 was calculated. The evaluation of silicon dioxide (Teos) scratches was to observe the scratches of silicon dioxide (Teos) after polishing under an optical microscope; the evaluation of the dishing defect was to use the STI3 mode wafer manufactured by SKW to perform the dishing defect evaluation polishing experiment, and the dishing defect depth was evaluated by AFM analysis. Table 2 was obtained.

[0054] Table 2

[0055] As shown in Table 2, compared with Comparative Examples 1 to 6 in which no adrenaline compounds were added, the polishing selectivity ratios of silicon dioxide (Teos) and Si3N4 in Examples 1 to 6 in which adrenaline compounds were added were all greater than 30. However, the polishing selectivity ratios of silicon dioxide (Teos) and Si3N4 in Comparative Examples 1 to 6 were significantly reduced, and the scratches and depressions of silicon dioxide (Teos) also increased sharply, which could not meet the polishing requirements.

[0056] It can be seen that the addition of adrenaline compounds in Examples 1 to 6 can significantly inhibit the removal rate of silicon nitride while increasing the polishing rate of the polishing liquid on the silicon dioxide dielectric layer, thereby increasing the selectivity of silicon dioxide to silicon nitride. At the same time, there are no obvious visible scratches on the surface of silicon dioxide (Teos) in Examples 1 to 6, and the depression is greatly reduced.

[0057] Therefore, the chemical mechanical polishing liquid adjusts the silicon dioxide / silicon nitride selectivity of the polishing liquid by controlling the content of cerium oxide abrasive particles, adrenaline compounds, organic high molecular polymers, and organic polyacids, while avoiding or reducing the generation of defects such as dents and scratches during the polishing process.

[0058] Advantages of the present invention: The chemical mechanical polishing liquid, by adding adrenaline compounds, can effectively suppress the polishing rate of silicon nitride while increasing the polishing rate of the polishing liquid on the silicon dioxide dielectric layer, thereby increasing the polishing selectivity of silicon dioxide / silicon nitride. By adding adrenaline compounds, the occurrence of defects such as dents and scratches during the polishing process can also be reduced or avoided. Adrenaline compounds, organic high molecular polymers and organic polyacids work together to form a stable polishing liquid by adjusting the content of each substance, which can make the polishing selectivity of silicon dioxide / silicon nitride greater than 30, and effectively avoid or reduce the occurrence of defects such as dents and scratches during the polishing process.

[0059] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the art within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A chemical mechanical polishing liquid, characterized in that: It includes adrenaline compounds, sol-gel type cerium oxide abrasive particles, organic high molecular polymers and organic polyacids. The molecular structure of the adrenaline compounds is: , wherein R1 is x,y-benzenediol or x,y,z-benzenetriol, wherein x,y,z are numbers from 2 to 6; R2 and R3 are hydrogen atoms, alkanes with carbon numbers of 1 to 6, or alcohols with carbon numbers of 1 to 6; n is a number from 1 to 3, and the mass percentage of the adrenaline compound is 0.05%-0.8%.

2. A chemical mechanical polishing solution according to claim 1, characterized in that: The mass percentage of the organic high molecular polymer is 0.05%-1%.

3. A chemical mechanical polishing solution according to claim 1, characterized in that: The mass percentage of the abrasive particles is 0.5%-10%.

4. A chemical mechanical polishing solution according to claim 1, characterized in that: The mass percentage of the organic polyacid is 0.1%-1.3%.

5. A chemical mechanical polishing solution according to claim 1, characterized in that: The adrenaline compounds include but are not limited to the following optical isomers and mixtures thereof: R configuration, S configuration, and racemic configuration.

6. A chemical mechanical polishing solution according to claim 1, characterized in that: The organic high molecular polymer is one or more of polyacrylic acid and its salt compounds, polyvinyl pyrrolidone and / or polyethylene glycol, and the organic polyacid is one or more of acetic acid, glycine, citric acid, iminodiacetic acid, malonic acid and / or succinic acid.

7. The method for preparing a chemical mechanical polishing solution according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: Configure the required components; Mix all ingredients well.

8. Use of a chemical mechanical polishing liquid according to any one of claims 1 to 6 in polishing of silicon dioxide and silicon nitride.

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