Dispersion liquid, polishing composition, and method for manufacturing semiconductor device

Abstract

The embodiment of the invention provides dispersion liquid, a grinding composition and a preparation method of a semiconductor device. The dispersion liquid comprises a solvent, inorganic nanoparticles, a conductivity regulator, an anionic polymer and a non-anionic polymer, the conductivity of the dispersion liquid is greater than or equal to 5ms / cm. The grinding composition can be obtained after the dispersion liquid and an oxidizing agent are compounded, the grinding composition is particularly suitable for leveling treatment of a structure with metal tungsten and a dielectric material at the same time, the leveling effect of the metal tungsten treated by the grinding composition is good, and Topology on the surface of a ground device can meet the requirement of a high-performance semiconductor device.

Description

Technical Field

[0001] This application relates to the technical field of semiconductor device fabrication, and specifically relates to dispersions, polishing compositions, and methods for fabricating semiconductor devices. Background Art

[0002] In the semiconductor device manufacturing process, a polishing process needs to be introduced in stages such as the front-end process and the back-end process to achieve planarization of specific regions of a wafer or semiconductor preform. In the above-mentioned front-end process, the semiconductor preform often involves the connection of multiple materials, mainly including the connection of a metal gate and multiple dielectric materials; and the preparation of the metal gate involves polishing it to obtain a metal gate with an ideal height. However, since there are multiple film layers composed of materials such as silicon nitride and silicon oxide at the polishing interface of the metal gate. In addition, due to the characteristics of semiconductor devices, the requirements for the picture topology of the polished interface are extremely strict, so the process window for polishing the metal gate is extremely small. Therefore, the performance requirements for the polishing liquid used in the polishing process are extremely high. Therefore, a polishing liquid with relatively excellent comprehensive performance is needed. Summary of the Invention

[0003] Embodiments of this application provide a dispersion, a polishing composition, and a method for fabricating a semiconductor device. The dispersion can be compounded with an oxidizing agent to obtain a polishing composition. This polishing composition is particularly suitable for planarization treatment of a structure simultaneously having tungsten metal and a dielectric material. The planarization effect of the tungsten metal treated with this polishing composition is better, and the Topology of the surface of the polished device can meet the requirements of high-performance semiconductor devices.

[0004] In a first aspect of the embodiments of this application, a dispersion is provided, including: a solvent, inorganic nanoparticles, a conductivity regulator, an anionic polymer, and a non-ionic polymer; the conductivity of the dispersion ≥ 5 ms / cm.

[0005] The above-mentioned dispersion liquid and the polishing composition obtained by compounding it with an oxidant both have excellent stability and are suitable for planarization treatment of a structure having both tungsten metal and dielectric materials. In addition, in the chemical environment of the polishing composition obtained by compounding it with an oxidant, the physical polishing effect of the inorganic nanoparticles on tungsten metal is better, the removal rate is stable, and the polishing rates of tungsten metal and dielectric materials can be adjusted more flexibly, and the adjustment range is wide. The removal selectivity of tungsten metal to dielectric materials can be flexibly adjusted within a relatively wide range, and it is beneficial to achieve a high removal selectivity of tungsten metal to dielectric materials, that is, the compatibility with dielectric materials is relatively high. In addition, in the dispersion liquid system of the present application and the polishing composition system formed therefrom, an anionic polymer and a non-ionic polymer can form an inter-polymer complex and form a surface inhibition layer on the surface of tungsten metal through electrostatic adsorption, slowing down the oxidation rate of tungsten metal by the oxidant, making the reaction proceed smoothly, thereby effectively reducing the dents, erosion, and defects of tungsten metal after planarization treatment, and improving the electrical performance of the final semiconductor device. In addition, it is also beneficial to achieve precise control of the thickness of the polished tungsten metal. Under the synergistic effect of the above factors, in the same workpiece to be planarized, the height difference of tungsten metal with different line widths after planarization treatment is small, and the workpiece after planarization treatment has excellent Topology, thereby effectively improving the performance of the final semiconductor device.

[0006] In some embodiments of the present application, the conductivity of the dispersion liquid is in the range of greater than 10 ms / cm to less than or equal to 30 ms / cm. In this way, the mechanical action of the inorganic nanoparticles can be further promoted, the planarization effect on tungsten metal can be improved, and it is also more beneficial to improve the removal selectivity of tungsten metal to dielectric materials.

[0007] In some embodiments of the present application, the conductivity regulator includes ammonium nitrate and / or ammonium sulfate; the conductivity regulator accounts for 0.1%-3% of the mass of the dispersion liquid. In this way, it is more beneficial to improve the planarization effect of the final polishing composition on tungsten metal and more beneficial to improve the removal selectivity of tungsten metal to dielectric materials.

[0008] In some embodiments of the present application, the anionic polymer includes one or more of polyacrylic acid, polymethacrylic acid, polymaleic acid, maleic acid-acrylic acid copolymer, and poly(2-acrylamide-2-methyl-1-propanesulfonic acid); and / or,

[0009] The non-anionic polymers include one or more of polyvinylpyrrolidone, polyacrylamide, poly(N-isopropylacrylamide), and poly(N-vinylacetamide). The above-mentioned anionic polymers and non-anionic polymers can quickly form a relatively stable polymer complex in the system of the abrasive composition provided in the embodiments of the present application and adsorb on the surface of tungsten metal through electrostatic interaction, optimizing the Topology of the grinding interface.

[0010] In some embodiments of the present application, the weight-average molecular weight of the anionic polymer ≤ 1×10 6 g / mol, and the weight-average molecular weight of the non-anionic polymer ≤ 5×10 4 g / mol. In this way, it is beneficial to control the viscosity of the dispersion liquid within a lower range, which is conducive to the compounding of the abrasive composition and controlling its viscosity within a suitable range, and further conducive to improving the grinding efficiency and effect.

[0011] In some embodiments of the present application, the sum of the masses of the anionic polymer and the non-anionic polymer accounts for 0.001%-2% of the mass of the dispersion liquid. In this way, it is beneficial to the compounding of the dispersion liquid and the oxidant to obtain an abrasive composition with a suitable viscosity, and the above polymers can be adsorbed on the surface of tungsten metal quickly and relatively fully, thus ensuring a better planarization treatment effect.

[0012] In some embodiments of the present application, the pH value of the dispersion liquid is 2-6. Controlling the pH value of the dispersion liquid within the range of 2-6 is beneficial to optimizing the planarization effect and is more conducive to realizing the adjustment of the removal selectivity ratio of tungsten metal to the dielectric material.

[0013] In some embodiments of the present application, the dispersion liquid further includes a pH regulator; the pH regulator includes an inorganic acid, or the pH regulator includes an organic amine and / or ammonia water. The above pH regulator has good compatibility with the dispersion liquid and the final abrasive composition of the present application, is stable in nature, and does not introduce metal impurity ions.

[0014] In some embodiments of the present application, the inorganic nanoparticles include silica nanoparticles and / or alumina nanoparticles; the inorganic nanoparticles account for 0.1%-5% of the mass of the dispersion liquid. In this way, it is beneficial to the comprehensive performance of the dispersion liquid.

[0015] In some embodiments of the present application, the mass content of metal elements in the dispersion liquid is less than 1 ppm. In this way, it is possible to reduce or even avoid the decomposition of the oxidant caused by the presence of free metal ions in the final abrasive composition, and it is also possible to reduce or avoid the risk of metal ions remaining on the surface of the device after planarization treatment.

[0016] In some embodiments of the present application, the solvent includes water. Water can effectively disperse other components in the dispersion of the present application to form a stable and uniform dispersion, which is beneficial to providing a uniform and stable grinding composition.

[0017] The second aspect of the embodiments of the present application provides a grinding composition, including the aforementioned dispersion provided by the embodiments of the present application, and an oxidant; the conductivity of the grinding composition is ≥5 ms / cm.

[0018] In the grinding composition provided by the present application, the inorganic nanoparticles have a better physical grinding effect on tungsten metal, with a stable removal rate, and can more flexibly control the grinding rates of tungsten metal and dielectric materials. The control range is wide, and a high removal selectivity of tungsten metal to dielectric materials can be achieved, that is, the compatibility with dielectric materials is relatively high. In addition, in the grinding composition system of the present application, anionic polymers and non-anionic polymers can form an inter-polymer complex and form a surface inhibition layer on the surface of tungsten metal through electrostatic adsorption, slowing down the oxidation rate of tungsten metal by the oxidant, making the reaction proceed smoothly, thereby effectively reducing the dents, erosion, and defects of tungsten metal after planarization treatment, and improving the electrical performance of the final semiconductor device; in addition, it is also beneficial to accurately control the thickness of the ground tungsten metal. Under the synergistic effect of the above factors, in the same workpiece to be planarized, the grinding composition provided by the embodiments of the present application is applicable to the planarization treatment of structures with tungsten metal and dielectric materials at the same time, and the height difference of tungsten metal with different line widths after planarization treatment is small, and the workpiece after planarization treatment has a better Topology, thereby effectively improving the performance of the final semiconductor device.

[0019] In some embodiments of the present application, the oxidant includes hydrogen peroxide; the oxidant accounts for 0.1%-5% of the mass of the composition. In the system of the grinding composition of the present application, hydrogen peroxide can slowly oxidize the surface of tungsten metal, which is also beneficial to obtaining high-quality tungsten metal gates. Controlling the mass ratio of the oxidant within the above range is beneficial to improving the performance of the finally prepared device.

[0020] The embodiments of the present application also provide a method for manufacturing a semiconductor device, including:

[0021] Placing a semiconductor preform or substrate in a grinding device and placing it opposite to the grinding pad of the grinding device;

[0022] Providing the grinding composition provided by the embodiments of the present application between the semiconductor preform or substrate and the grinding pad, and enabling the grinding pad to grind the semiconductor preform or substrate.

[0023] The manufacturing method of the semiconductor device provided by the embodiment of the present application has strong process reliability and is suitable for large-scale industrial production. At the same time, due to the use of the polishing composition provided by the embodiment of the present application, the above manufacturing method can be used to manufacture semiconductor devices such as high-integration high-precision chips, and the performance of the semiconductor device manufactured thereby is better and the yield is high. Detailed implementation manners

[0024] As the size of semiconductor devices continues to shrink, the traditional polysilicon gate structure faces many challenges; for example, excessive gate leakage, difficulty in precisely controlling the threshold voltage, etc. To overcome the above problems, a metal gate system is used to replace the original polysilicon gate system in the related art; the metal gate can be, for example, a metal tungsten gate. In the manufacturing process of semiconductor devices, the manufacturing of metal gates generally includes: sequentially depositing a dielectric material and a gate metal on a specific area of the substrate surface, and then performing a planarization process on the workpiece to be planarized with the deposited gate metal to obtain a metal gate with a target height and a target morphology and a polishing interface with better Topology. In addition, the workpiece to be planarized often involves the connection of various materials, including gate metals, dielectric materials, etc.; taking tungsten as the gate metal as an example, the materials connected thereto can include dielectrics such as silicon nitride and silicon oxide. Specifically, tungsten metal is deposited in the opening formed by the dielectric material layer. After deposition, it is necessary to polish to remove the excessive tungsten metal on the dielectric material to form a metal gate in the dielectric layer. Therefore, in the polishing process, it is often necessary to perform highly selective removal of tungsten metal; that is, to make tungsten metal and the dielectric material exhibit different polishing removal rates.

[0025] Polishing generally involves placing a workpiece to be planarized on a polishing pad of a polishing device, providing a polishing composition between the surface of the polishing pad and the workpiece to be planarized, and relatively moving the polishing pad and the workpiece to be planarized. The characteristics of the polishing composition have an important impact on the erosion of the dielectric layer, the depression of the metal gate, the generation of defects, and the polishing removal selectivity during the planarization process; moreover, even for the same material, regions with different line widths made of the same material may be provided on the surface to be planarized. After polishing, there is often a certain height difference between the same material with different line widths, but this height difference will affect the performance of semiconductor devices. How to reduce the above height difference is also the focus of attention in the industry; the smaller the above height difference, the better the Topology of the polishing interface. In some scenarios, the polishing composition generally includes an oxidant. To maintain the stability of the polishing composition, the oxidant is generally compounded with other components of the polishing composition (i.e., the dispersion liquid) before use. It can be understood that the characteristics of the polishing composition or the dispersion liquid are one of the keys to determining the planarization effect. In related technologies, for the polishing liquid of tungsten metal, hydrogen peroxide is usually used as the oxidant, and ferric nitrate is needed as a catalyst to planarize tungsten metal. Specifically, through the chemical reaction between iron and hydrogen peroxide, strongly oxidizing hydroxyl radicals are generated to oxidize tungsten metal to tungsten trioxide (WO 3 ) which is easier to remove, and at the same time, the above oxides are removed by the mechanical action of nanoparticles, but the planarization effect is not good. Therefore, there is an urgent need to provide a dispersion liquid and a polishing composition with relatively excellent comprehensive performance.

[0026] An embodiment of the present application provides a dispersion liquid, including: a solvent, inorganic nanoparticles, a conductivity regulator, an anionic polymer, and a non-ionic polymer; the conductivity of the dispersion liquid ≥ 5 ms / cm. In the embodiment of the present application, the anionic polymer refers to a polymer whose molecular chain exhibits anionic characteristics when dispersed in a high-dielectric medium such as water.

[0027] The above-mentioned dispersion liquid and the grinding composition obtained by compounding it with an oxidant both have excellent stability and are suitable for planarization treatment of structures having both tungsten metal and dielectric materials. Specifically, the conductivity of the dispersion liquid provided in this application is ≥5 ms / cm. In the chemical environment of the grinding composition formed by compounding it with an oxidant, the oxidant can effectively oxidize the surface layer of tungsten metal and generate an oxide film layer on the surface of tungsten metal. The inorganic nanoparticles, supplemented by mechanical action, can remove the above-mentioned oxide film layer, thereby achieving planarization of tungsten metal through the dual effects of chemistry and physics. In addition, in the chemical environment with the above-mentioned conductivity, the physical grinding effect of the inorganic nanoparticles on tungsten metal is better, the removal rate is stable, and the grinding rates of tungsten metal and dielectric materials (including materials such as silicon nitride, silicon oxide, and silicon oxynitride) can be more flexibly adjusted, and the adjustment range is wide. The removal selectivity of tungsten metal to dielectric materials can be flexibly adjusted within a relatively wide range, and it is conducive to achieving a high removal selectivity of tungsten metal to dielectric materials, that is, the compatibility with dielectric materials is relatively high. In addition, in the dispersion liquid system and the grinding composition system of this application, an anionic polymer and a non-ionic polymer can form an inter-polymer complex and form a surface inhibition layer on the surface of tungsten metal through electrostatic adsorption, slowing down the oxidation rate of tungsten metal by the oxidant and making the reaction proceed smoothly. Thus, the depressions, erosions, and defects of tungsten metal after planarization treatment can be effectively reduced, and the electrical performance of the final semiconductor device can be improved. In addition, it is also conducive to accurately controlling the thickness of the ground tungsten metal (when the grinding object is the gate metal, it corresponds to facilitating the control of the height of the metal gate). Under the synergistic effect of the above factors, in the same workpiece to be planarized, the height difference of tungsten metal with different line widths after planarization treatment is small (similarly, the height difference of metal gate electrodes with different line widths is small), and the workpiece after planarization treatment has excellent Topology, thereby effectively improving the performance of the final semiconductor device. In addition, the dispersion liquid provided in the embodiments of this application still has high stability at high conductivity. It should be noted that the removal selectivity of tungsten metal to dielectric materials = the removal rate of tungsten metal / the removal rate of dielectric materials. In some embodiments of this application, the removal selectivity of tungsten metal to dielectric materials ≥15; for example, ≥20, ≥25, ≥30. Specifically, the removal selectivity of tungsten metal to dielectric materials can be, for example, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, etc.

[0028] It should be noted that the dispersion liquid of the embodiments of the present application can be used to provide a polishing liquid with a relatively high removal selectivity of tungsten metal / dielectric material, but it does not limit that the removal selectivity of tungsten metal / dielectric material of the final polishing liquid must be greater than or equal to 15; in some special application scenarios, the removal selectivity of tungsten metal / dielectric material can also be controlled within the required range by further fine-tuning the components.

[0029] In the embodiments of the present application, the conductivity of the dispersion liquid is the conductivity at room temperature (25±3°C); specifically, it includes but is not limited to measuring the conductivity of the dispersion liquid at room temperature using a conductivity tester.

[0030] In the embodiments of the present application, the conductivity of the dispersion liquid can be, for example, 5 ms / cm, 6 ms / cm, 7 ms / cm, 8 ms / cm, 9 ms / cm, 10 ms / cm, 11 ms / cm, 12 ms / cm, 13 ms / cm, 14 ms / cm, 15 ms / cm, 16 ms / cm, 17 ms / cm, 18 ms / cm, 19 ms / cm, 20 ms / cm, 21 ms / cm, 22 ms / cm, 23 ms / cm, 24 ms / cm, 25 ms / cm, 26 ms / cm, 27 ms / cm, 28 ms / cm, 29 ms / cm, 30 ms / cm, 32 ms / cm, etc. If the above conductivity is too low (<5 ms / cm), the removal rate of the final polishing composition on the wafer surface will be too low.

[0031] In the embodiments of the present application, it includes but is not limited to using nuclear magnetic resonance to test the presence of non-anionic polymers and anionic polymers in the dispersion liquid.

[0032] In some embodiments of the present application, the conductivity of the dispersion is in the range greater than 10 ms / cm to less than or equal to 30 ms / cm. In some specific embodiments, for example, it can be 10.1 ms / cm - 30 ms / cm. For the specific dispersion system of the embodiments of the present application, when the conductivity of the dispersion is controlled within the above range, when it is compounded with an oxidant to form a polishing composition, it can further promote the mechanical action of the inorganic nanoparticles, further improve the planarization effect on tungsten metal, be more conducive to reducing the height difference of tungsten metal with different line widths after planarization treatment, optimize the Topology after planarization, and be more conducive to improving the performance of the final semiconductor device. Specifically, the conductivity of the dispersion can be, for example, 10.1 ms / cm, 10.2 ms / cm, 10.3 ms / cm, 10.4 ms / cm, 10.5 ms / cm, 10.8 ms / cm, 11 ms / cm, 11.2 ms / cm, 11.5 ms / cm, 11.8, 12 ms / cm, 13 ms / cm, 14 ms / cm, 15 ms / cm, 16 ms / cm, 17 ms / cm, 18 ms / cm, 19 ms / cm, 20 ms / cm, 21 ms / cm, 22 ms / cm, 23 ms / cm, 24 ms / cm, 25 ms / cm, 26 ms / cm, 27 ms / cm, 28 ms / cm, 29 ms / cm, 30 ms / cm. For the convenience of description, the conductivity of the dispersion is denoted as X, and 10 ms / cm < X ≤ 30 ms / cm.

[0033] In some embodiments of the present application, the conductivity regulator includes ammonium nitrate and / or ammonium sulfate. Ammonium nitrate and ammonium sulfate have good compatibility and stability with the dispersion and the final polishing composition of the embodiments of the present application, will not have a negative effect on the planarization process, and the above two substances can flexibly adjust the conductivity of the dispersion to the range recommended by the present application. Moreover, even at high conductivity (for example, 20 ms / cm - 30 ms / cm), it still has high solution stability and will not gel. The polishing composition obtained by compounding with the oxidation solution after long-term storage at room temperature still has excellent polishing performance. With the cooperation of the above conductivity regulator, non-ionic polymer, and anionic polymer, in the dispersion system of the embodiments of the present application, it can improve the selective removal ratio of tungsten metal to the dielectric material while reducing the height difference of tungsten metal with different line widths. In some specific embodiments, the height difference after polishing of the polishing composition obtained by compounding the dispersion with an oxidant for 0.18 / 0.18 μm tungsten metal and 1 / 1 μm area is ≤ 15 nm, for example, 15 nm, 14 nm, 13 nm, 12 nm, 10 nm, 9 nm, 8 nm, 7 nm, 6 nm, 5 nm, 4 nm, 3 nm, etc.

[0034] In addition, the above conductivity regulator does not introduce metal ion impurities. In the embodiments of the present application, the presence of the conductivity regulator is detected by, including but not limited to, testing anions and cations in the dispersion using an ion chromatograph.

[0035] In some embodiments of the present application, the conductivity regulator accounts for 0.1%-3% of the mass of the dispersion. In some specific embodiments, the conductivity regulator is selected from ammonium nitrate and / or ammonium sulfate, and the mass of the conductivity regulator accounts for 0.1%-3% of the mass of the dispersion. In this way, it is easy to adjust the conductivity of the dispersion to the range recommended in the present application, which is more conducive to improving the planarization effect of the final polishing composition on tungsten metal and more conducive to improving the removal selectivity of tungsten metal to the dielectric material. Specifically, the mass of the conductivity regulator can be, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 2.95%, 3%, etc. of the mass of the dispersion. In the embodiments of the present application, the mass ratio of the conductivity regulator in the dispersion is detected by, including but not limited to, using an ion chromatograph.

[0036] In some embodiments of the present application, the anionic polymer includes one or more of polyacrylic acid (PAA), polymethacrylic acid, polymaleic acid (HPMA), maleic acid-acrylic acid copolymer, and poly(2-acrylamido-2-methyl-1-propanesulfonic acid). In some embodiments of the present application, the non-anionic polymer includes one or more of polyvinylpyrrolidone (PVP), polyacrylamide (PAM), poly(N-isopropylacrylamide) (PNIPAM), and poly(N-vinylacetamide) (PNVA). In the system of the polishing liquid composition provided in the embodiments of the present application, the above anionic polymer and non-anionic polymer can quickly form a relatively stable polymer complex and adsorb on the surface of tungsten metal through electrostatic interaction, which is more conducive to slowing down the oxidation reaction of tungsten metal, effectively reducing the depression and erosion of tungsten metal after polishing, and optimizing the Topology of the polishing interface.

[0037] In some embodiments of the present application, the sum of the masses of the anionic polymer and the non-anionic polymer accounts for 0.001%-2% of the mass of the dispersion liquid. In this way, during the planarization treatment, a surface inhibition layer with an appropriate thickness can be quickly and fully attached to the surface of tungsten metal, and the oxidation reaction of tungsten metal can be controlled within a better range; it is also beneficial to control the viscosity of the dispersion liquid within an appropriate range, which is conducive to its compounding with the oxidant to obtain a polishing composition with an appropriate viscosity, thereby ensuring a better planarization treatment effect. Specifically, the sum of the masses of the anionic polymer and the non-anionic polymer can be, for example, 0.001%, 0.002%, 0.005%, 0.008%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, etc. of the mass of the dispersion liquid. In the embodiments of the present application, the mass ratio of the anionic polymer and the non-anionic polymer in the dispersion liquid is measured by, but not limited to, gel permeation chromatography.

[0038] In some embodiments of the present application, the molar ratio of the anionic polymer to the non-anionic polymer is 1:(0.1-10000). In this way, during the planarization treatment, it is more conducive to quickly attaching the polymer intermolecular complex to the surface of tungsten metal. Specifically, the molar ratio of the anionic polymer to the non-anionic polymer can be, for example, 1:0.1, 1:0.2, 1:0.5, 1:0.8, 1:1, 1:2, 1:5, 1:10, 1:20, 1:50, 1:80, 1:100, 1:150, 1:200, 1:500, 1:800, 1:1000, 1:2000, 1:3000, 1:4000, 1:5000, 1:6000, 1:7000, 1:8000, 1:9000, 1:10000, etc.

[0039] In some embodiments of the present application, the weight-average molecular weight Mw of the anionic polymer ≤ 1×10 6 g / mol, and the weight-average molecular weight Mw of the non-anionic polymer ≤ 5×10 4g / mol. Thus, it is beneficial to control the viscosity of the dispersion liquid within a relatively low range, which is conducive to the compounding of the grinding composition and the control of its viscosity within a suitable range, and further conducive to improving the efficiency and effect of grinding, effectively reducing the risk of uneven grinding. Specifically, the weight average molecular weight of the anionic polymer can be, for example, 1000 g / mol, 2000 g / mol, 3000 g / mol, 4000 g / mol, 5000 g / mol, 6000 g / mol, 7000 g / mol, 8000 g / mol, 9000 g / mol, 10000 g / mol, 15000 g / mol, 20000 g / mol, 25000 g / mol, 30000 g / mol, 35000 g / mol, 40000 g / mol, 45000 g / mol, 50000 g / mol, 80000 g / mol, 1×10 5 g / mol, 2×10 5 g / mol, 5×10 5 g / mol, 8×10 5 g / mol, 1×10 6 g / mol. In the embodiments of the present application, the weight average molecular weight of the non-anionic polymer can be, for example, 1000 g / mol, 2000 g / mol, 3000 g / mol, 4000 g / mol, 5000 g / mol, 6000 g / mol, 7000 g / mol, 8000 g / mol, 9000 g / mol, 10000 g / mol, 15000 g / mol, 20000 g / mol, 25000 g / mol, 30000 g / mol, 35000 g / mol, 40000 g / mol, 45000 g / mol, 50000 g / mol. In the embodiments of the present application, the weight average molecular weight Mw of the anionic polymer and the non-anionic polymer is tested by, including but not limited to, Gel Permeation Chromatography (GPC).

[0040] In some embodiments of the present application, the dispersion liquid further includes a pH regulator. It can be understood that the pH regulator is used to adjust the pH value of the dispersion liquid. In some embodiments of the present application, the pH value of the dispersion liquid is 2 - 6. Controlling the pH value of the dispersion liquid within the range of 2 - 6 is beneficial to optimizing the planarization effect and more beneficial to realizing the adjustment of the removal selectivity of tungsten metal to the dielectric material. Specifically, the pH value of the dispersion liquid can be, for example, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8, 5, 5.2, 5.5, 5.8, 6, etc. In the embodiments of the present application, the pH value of the dispersion liquid is tested by, including but not limited to, a pH meter.

[0041] In some embodiments of the present application, the pH regulator includes an inorganic acid, or the pH regulator includes an organic amine and / or ammonia water. In the embodiments of the present application, the above-mentioned inorganic acid can be, for example, nitric acid, sulfuric acid, etc. In some specific embodiments, the inorganic acid is selected from nitric acid. Using nitric acid as the pH regulator is beneficial for it to adapt to the scenarios of tungsten metal and dielectric layer planarization. In the embodiments of the present application, the organic amine can be, for example, alkylamine, aniline, naphthylamine, but not limited thereto. Specifically, the alkylamine can be, for example, R 3 -NH 2 、R 4 -NH-R 5 , where R 3 、R 4 、R 5 are each independently an alkyl group; the above-mentioned alkyl group can be, for example, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, etc.; the alkylamine can be, for example, one or more of diethylamine, triethylamine, di-n-propylamine, n-butylamine, etc. In some specific embodiments, the pH regulator includes ammonia water. In the embodiments of the present application, the above-mentioned pH regulator has good compatibility with the dispersion liquid and the final grinding composition of the present application, stable properties, and does not introduce metal impurity ions. It can be understood that in some embodiments, the regulator is an inorganic acid, and in this case, it is more beneficial to adjust the dispersion liquid and the grinding composition towards a pH value of 2; thus, it is more beneficial to improve the grinding rate of the grinding composition on tungsten metal. In other embodiments, the regulator is an organic amine and / or ammonia water, and in this case, it is more beneficial to adjust the dispersion liquid and the grinding composition towards a pH value of 6; thus, the influence on the surface potential of crystalline substances such as silicon oxide and silicon nitride is more obvious, and it is also more beneficial to improve the Topology of the device after grinding.

[0042] As semiconductor devices are miniaturized, the requirements for planarization treatment in the semiconductor device manufacturing process have become increasingly high. The polishing compositions used in related technologies contain a relatively large amount of metal ions, which exhibit strong chemical oxidation during the planarization treatment of tungsten, generating a large amount of oxides and having a fast removal rate. However, the overly strong chemical oxidation will cause a large number of corrosion, depressions, and defect structures to form on the surface of metallic tungsten, and there is a high risk that metal ions will remain on the surface of the device after planarization treatment. All of the above will affect the performance of the device and also the yield of semiconductor devices. In addition, metal ions will accelerate the decomposition of oxidants such as hydrogen peroxide, affecting the planarization effect. In some embodiments of the present application, the mass content of metal elements in the dispersion liquid is less than 10 ppm. In some specific embodiments, the mass content of metal elements in the dispersion liquid is less than or equal to 1 ppm. In some specific embodiments, the content of metal elements in the dispersion liquid approaches 0 infinitely, or even is 0. Thus, it is possible to reduce or even avoid the decomposition of oxidants caused by free metal ions in the final polishing composition, and it is also possible to reduce or avoid the risk of metal ions remaining on the surface of the device after planarization treatment. Specifically, the above metal elements include, but are not limited to, iron (Fe), copper (Cu), cobalt (Co), chromium (Cr), manganese (Mn), nickel (Ni), titanium (Ti), zinc (Zn), etc.

[0043] In the embodiments of the present application, the content of metal elements in the dispersion liquid is tested by, but not limited to, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) or Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES).

[0044] In the embodiments of the present application, inorganic nanoparticles refer to inorganic particles with a hydrated particle size in the nanometer range. The hydrated particle size refers to the apparent diameter of nanoparticles in solution measured by dynamic light scattering technology. It is a hydrodynamic diameter that represents the size of nanoparticles in solution due to their diffusion behavior. The hydrated particle size includes the solvent layer bound to the surface of the nanoparticles or other molecules that move with the particles, and thus is slightly larger than the actual physical size of the inorganic nanoparticles. In some embodiments of the present application, the inorganic nanoparticles include silica nanoparticles. In some embodiments, the particle size of the silica nanoparticles can be, for example, ≥5 nm, such as 5 nm - 10 nm, ≥10 nm, 10 nm - 20 nm, ≥20 nm, 20 nm - 30 nm, ≥30 nm, 50 nm, 60 nm, 80 nm, 100 nm, 120 nm, 130 nm, 140 nm, 150 nm, etc. In some specific embodiments, the hydrated particle size of the silica nanoparticles is 30 nm - 150 nm, etc. In the abrasive composition provided by the dispersion of the present application, the inorganic nanoparticles with the above hydrated particle size have a good abrasive effect on tungsten metal. Specifically, the removal efficiency of tungsten metal is relatively high and it is not easy to cause scratch defects on the object to be planarized (i.e., the workpiece to be abraded); moreover, the inorganic nanoparticles of the above size are easily uniformly distributed in the dispersion, which is conducive to forming a uniform abrasive composition. In the embodiments of the present application, the presence and morphology of the inorganic nanoparticles can be observed by using SEM-EDS (scanning electron microscope - energy dispersive spectrometer) in combination; in the embodiments of the present application, the particle size of the inorganic nanoparticles can be measured, for example, by a laser particle size analyzer.

[0045] In the embodiments of the present application, the inorganic nanoparticles can be electrically neutral, or the inorganic nanoparticles are positively charged or negatively charged. In some embodiments of the present application, the inorganic nanoparticles are negatively charged; that is, the zeta potential of the inorganic nanoparticles < 0. In the embodiments of the present application, including but not limited to, a zeta potential analyzer is used to test the zeta potential of the inorganic nanoparticles.

[0046] In some embodiments of the present application, the inorganic nanoparticles account for 0.1% - 5% of the mass of the dispersion. In this way, it is beneficial to the comprehensive performance of the dispersion. Specifically, the mass ratio of the inorganic nanoparticles in the dispersion can be, for example, 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.5%, 2.6%, 2.8%, 3%, 3.2%, 3.5%, 3.6%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, 5%, etc. In the embodiments of the present application, including but not limited to, thermogravimetric analysis (TGA) is used to test the mass ratio of the inorganic nanoparticles in the dispersion.

[0047] In some embodiments of the present application, the solvent of the dispersion liquid includes water. In some specific embodiments, the solvent of the dispersion liquid is water. Water can effectively disperse other components in the dispersion liquid of the present application to form a stable and uniform dispersion liquid, which is beneficial to providing a uniform and stable grinding composition. It can be understood that in some embodiments, the solvent is deionized water.

[0048] In some embodiments of the present application, the preparation of the dispersion liquid includes: mixing inorganic nanoparticles, a conductivity regulator, an anionic polymer, and a nonionic polymer in a solvent. In some specific embodiments, the preparation of the dispersion liquid includes: mixing inorganic nanoparticles, a conductivity regulator, an anionic polymer, and a nonionic polymer evenly in a solvent, and then adding a pH regulator to adjust the pH of the mixture to a target value to obtain a dispersion liquid. In some embodiments of the present application, a sol containing inorganic nanoparticles can be directly added to the above-mentioned solvent; for example, silica sol, and the silica sol is specifically an aqueous dispersion liquid of silicon dioxide nanoparticles.

[0049] The embodiments of the present application also provide a grinding composition, including the aforementioned dispersion liquid provided by the embodiments of the present application, and an oxidant; the conductivity of the grinding composition is ≥5 ms / cm.

[0050] In the grinding composition provided by the present application, the physical grinding effect of the inorganic nanoparticles on tungsten metal is better, the removal rate is stable, and the grinding rates of tungsten metal and dielectric materials can be adjusted more flexibly. The adjustment range is wide, and a high removal selectivity of tungsten metal to dielectric materials can be achieved, that is, the compatibility with dielectric materials is relatively high. In addition, in the grinding composition system of the present application, an inter-polymer complex can be formed between the anionic polymer and the nonionic polymer, and a surface inhibition layer can be formed on the surface of tungsten metal through electrostatic adsorption, slowing down the oxidation rate of the oxidant to tungsten metal, making the reaction proceed smoothly, thereby effectively reducing the dents, erosion, and defects of tungsten metal after planarization treatment, and improving the electrical performance of the final semiconductor device; in addition, it is also beneficial to accurately control the thickness of the ground tungsten metal. Under the synergistic effect of the above factors, in the same workpiece to be planarized, the grinding composition provided by the embodiments of the present application is simultaneously applicable to the planarization treatment of a structure having tungsten metal and dielectric materials, and the height difference of tungsten metal with different line widths after planarization treatment is small. The workpiece after planarization treatment has a better Topology, thereby effectively improving the performance of the final semiconductor device.

[0051] In the embodiments of the present application, the conductivity of the grinding composition is the conductivity at room temperature (25±3°C); specifically, it includes but is not limited to measuring the conductivity of the dispersion liquid at room temperature using a conductivity tester.

[0052] In the embodiments of the present application, the conductivity of the polishing composition can be, for example, 5 ms / cm, 6 ms / cm, 7 ms / cm, 8 ms / cm, 9 ms / cm, 10 ms / cm, 11 ms / cm, 12 ms / cm, 13 ms / cm, 14 ms / cm, 15 ms / cm, 16 ms / cm, 17 ms / cm, 18 ms / cm, 19 ms / cm, 20 ms / cm, 21 ms / cm, 22 ms / cm, 23 ms / cm, 24 ms / cm, 25 ms / cm, 26 ms / cm, 27 ms / cm, 28 ms / cm, 29 ms / cm, 30 ms / cm, 32 ms / cm, etc. If the above conductivity is too low (<5 ms / cm), the removal rate of the polishing composition on the wafer surface will be too low.

[0053] In some embodiments of the present application, the conductivity of the polishing composition is in the range greater than 10 ms / cm to less than or equal to 30 ms / cm.

[0054] In some embodiments of the present application, the oxidizing agent includes hydrogen peroxide H 2 O 2 . In the system of the polishing composition of the present application, hydrogen peroxide can slowly oxidize the surface of tungsten metal to convert it into a softened WO 4 2- layer, and the above WO 4 2- layer is more easily removed, which is also beneficial to obtaining a high-quality tungsten metal gate.

[0055] In some embodiments of the present application, the oxidizing agent accounts for 0.1%-5% of the mass of the polishing composition. Controlling the mass ratio of the oxidizing agent within the above range is beneficial to controlling the oxidation rate of tungsten metal within a relatively gentle and stable range during the planarization process of tungsten metal, thereby being more beneficial to improving the planarization effect of tungsten metal and the performance of the final device. Specifically, the mass ratio of the oxidizing agent in the polishing composition can be, for example, 0.1%, 0.2%, 0.8%, 1%, 1.2%, 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.5%, 2.6%, 2.8%, 3%, 3.2%, 3.5%, 3.6%, 3.8%, 4%, 4.2%, 4.5%, 4.6%, 4.8%, 5%, etc. In some specific embodiments, the oxidizing agent is selected from hydrogen peroxide, and the mass ratio of hydrogen peroxide in the polishing composition is 0.1%-5%. In the embodiments of the present application, the mass content of hydrogen peroxide in the polishing composition can be tested by the potassium permanganate titration method.

[0056] In some embodiments of the present application, the conductivity regulator accounts for 0.095% - 3% of the mass of the abrasive composition. In some specific embodiments, the conductivity regulator accounts for 0.1% - 3% of the mass of the abrasive composition. Specifically, the mass ratio of the conductivity regulator in the abrasive composition can be, for example, 0.095%, 0.098%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 2.95%, 2.96%, 2.98%, 2.99%, 2.995%, 2.997%, 3%. In the embodiments of the present application, an ion chromatograph can be used to test the mass ratio of the conductivity regulator in the abrasive composition.

[0057] In some embodiments of the present application, the inorganic nanoparticles account for 0.095% - 5% of the mass of the abrasive composition. In some specific embodiments, the inorganic nanoparticles account for 0.1% - 5% of the mass of the abrasive composition. Specifically, the mass ratio of the inorganic nanoparticles in the abrasive composition can be, for example, 0.095%, 0.098%, 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.5%, 2.6%, 2.8%, 3%, 3.2%, 3.5%, 3.6%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, 4.9%, 4.95%, 4.99%, 4.995%, 5%. In the embodiments of the present application, TGA can be used to test the mass ratio of the inorganic nanoparticles in the abrasive composition.

[0058] In some embodiments of the present application, the pH value of the abrasive composition is 2 - 6. Thus, it is beneficial to optimize the planarization effect and more beneficial to realize the adjustment of the removal selectivity of tungsten metal to the dielectric material. Specifically, the pH value of the abrasive composition can be, for example, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8, 5, 5.2, 5.5, 5.8, 6, etc. In the embodiments of the present application, testing the pH value of the abrasive composition includes, but is not limited to, using a pH meter.

[0059] In some embodiments of the present application, the sum of the masses of the anionic polymer and the non-anionic polymer accounts for 0.00095% - 2% of the mass of the polishing composition. In some specific embodiments, the sum of the masses of the anionic polymer and the non-anionic polymer accounts for 0.001% - 2% of the mass of the polishing composition. In this way, it is beneficial to control the oxidation reaction of tungsten metal within a preferable range; it is also beneficial to control the viscosity of the polishing composition within a suitable range, thereby ensuring a more preferable planarization treatment effect. Specifically, for example, the sum of the masses of the above-mentioned anionic polymer and non-anionic polymer can be 0.00095%, 0.00098%, 0.001%, 0.002%, 0.005%, 0.008%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 1.95%, 1.96%, 1.98%, 1.99%, 1.995%, 1.998%, 2%, etc. of the mass of the dispersion liquid. In the embodiments of the present application, gel permeation chromatography can be used to test the mass ratio of the anionic polymer and the non-anionic polymer in the polishing composition.

[0060] In some embodiments of the present application, the mass content of metal elements in the polishing composition is less than 10 ppm. In some specific embodiments, the mass content of metal elements in the polishing composition is less than or equal to 1 ppm. In some specific embodiments, the content of metal elements in the polishing composition approaches 0 infinitely, or even is 0. For specific details, reference can be made to the description of the metal element content in the dispersion liquid part in the foregoing text, which will not be elaborated here.

[0061] The embodiments of the present application further provide a planarization method, including:

[0062] Using the polishing composition provided by the embodiments of the present application, bringing the surface of the object to be planarized into contact with the above-mentioned polishing composition and relatively moving the object to be planarized. In some embodiments, the surface of the object to be planarized has tungsten metal; further, the object to be planarized has both tungsten metal and the aforementioned dielectric material.

[0063] In the process of the planarization method provided by the embodiments of the present application, the polishing pad is flatly attached to the polishing table, the object to be planarized is fixed on the polishing head, and the surface to be polished of the object to be planarized is brought into contact with the polishing pad, and then pressed on the polishing pad with a certain pressure. When the planarization process is carried out, the polishing head rotates the object to be planarized, and the polishing table also rotates at a certain speed; at the same time, the polishing composition is added to the polishing pad at a certain rate and is spread on the polishing pad by centrifugal force. The object to be planarized realizes the planarization of tungsten metal under the dual action of chemistry and mechanics, and a polishing surface with better Topology is obtained.

[0064] After the above planarization process, substances such as residual abrasives on the surface of the polished object can be removed through a cleaning process.

[0065] The embodiments of the present application also provide a method for manufacturing a semiconductor device, including:

[0066] Placing a semiconductor preform or substrate in a polishing device and placing it opposite to the polishing pad of the polishing device;

[0067] Providing the polishing composition provided by the embodiments of the present application between the semiconductor preform or substrate and the polishing pad, and enabling the polishing pad to polish the semiconductor preform or substrate.

[0068] In some embodiments of the present application, the semiconductor preform includes a substrate and a dielectric layer formed on the substrate. The dielectric layer has openings, and tungsten metal is deposited in the openings. In some specific embodiments, the dielectric layer has openings with different opening widths, and tungsten metal is deposited in the above openings to form tungsten metal gates with different line widths. In the embodiments of the present application, the material of the above dielectric layer includes, but is not limited to, one or more of silicon oxide, silicon nitride, and silicon oxynitride.

[0069] In the embodiments of the present application, providing the polishing composition provided by the embodiments of the present application between the semiconductor preform or substrate and the polishing pad, and enabling the polishing pad to polish the semiconductor preform or substrate includes:

[0070] The polishing pad is flatly attached to the polishing table, the semiconductor preform or substrate is fixed on the polishing head, and the surface to be polished of the semiconductor preform or substrate is brought into contact with the polishing pad, and then pressed on the polishing pad with a certain pressure. When polishing (planarization process) is carried out, the polishing head rotates the semiconductor preform or substrate, and the polishing table also rotates at a certain speed; at the same time, the polishing composition is added to the polishing pad at a certain rate and is spread on the polishing pad by centrifugal force. The semiconductor preform or substrate realizes the planarization of tungsten metal under the dual action of chemistry and mechanics, and a polishing surface with better Topology can be obtained.

[0071] The manufacturing method of the semiconductor device provided by the embodiment of the present application has strong process reliability and is applicable to large-scale industrial production. At the same time, due to the use of the polishing composition provided by the embodiment of the present application, the above manufacturing method can be used to manufacture semiconductor devices such as high-integration high-precision chips, and the performance of the semiconductor device manufactured thereby is better and the yield is high.

[0072] The technical solution of the present application will be further described in the following through multiple embodiments.

[0073] Example 1

[0074] A dispersion liquid includes the following components by mass fraction: 2% of silicon oxide nanoparticles (the silicon oxide nanoparticles are negatively charged and the hydrated particle size is 120 nm), 0.5% of ammonium nitrate, 0.4% of a nonionic polymer (specifically PVP with a weight-average molecular weight Mw of 2500 g / mol), 0.05% of an anionic polymer (specifically PAA with an Mw of 5000 g / mol), the balance of a solvent (specifically deionized water) and a pH regulator, and the pH value of the dispersion liquid is 5; the conductivity of the dispersion liquid is 9.8 ms / cm.

[0075] Example 2

[0076] A dispersion liquid, different from that of Example 1 in that the mass proportion of the conductivity regulator in the dispersion liquid is adjusted to 0.4%; the conductivity of the dispersion liquid is 8.5 ms / cm.

[0077] Example 3

[0078] A dispersion liquid, different from that of Example 1 in that the mass proportion of PAA in the dispersion liquid is adjusted to 0.01%; the conductivity of the dispersion liquid is 10.1 ms / cm.

[0079] Example 4

[0080] A dispersion liquid, different from that of Example 1 in that the mass proportion of PAA in the dispersion liquid is adjusted to 0.01%, and the Mw of PAA is adjusted to 10000 g / mol; the conductivity of the dispersion liquid is 10.2 ms / cm.

[0081] Example 5

[0082] A dispersion liquid, comprising the following components by mass fraction: 2% of silicon oxide nanoparticles (the silicon oxide nanoparticles are negatively charged with a particle size of 120 nm), 0.5% of ammonium nitrate, 0.4% of a non-anionic polymer (specifically PVP with a weight-average molecular weight Mw of 2500 g / mol), 0.01% of an anionic polymer (specifically PAMPS with an Mw of 3000 g / mol), the balance being a solvent (specifically deionized water) and a pH regulator, and the pH value of the dispersion liquid is 5; the conductivity of the dispersion liquid is 10.2 ms / cm.

[0083] Example 6

[0084] A dispersion liquid, comprising the following components by mass fraction: 2% of silicon oxide nanoparticles (the silicon oxide nanoparticles are negatively charged with a particle size of 120 nm), 0.5% of ammonium nitrate, 0.4% of a non-anionic polymer (specifically PVP with a weight-average molecular weight Mw of 2500 g / mol), 0.01% of an anionic polymer (specifically HPMA poly(maleic acid) with an Mw of 2000 g / mol), the balance being a solvent (specifically deionized water) and a pH regulator, and the pH value of the dispersion liquid is 5; the conductivity of the dispersion liquid is 10.5 ms / cm.

[0085] Example 7

[0086] A dispersion liquid, comprising the following components by mass fraction: 2% of silicon oxide nanoparticles (the silicon oxide nanoparticles are negatively charged with a particle size of 120 nm), 0.5% of ammonium nitrate, 0.8% of a non-anionic polymer (specifically PVP with a weight-average molecular weight Mw of 2500 g / mol), 0.01% of an anionic polymer (specifically PAA with an Mw of 5000 g / mol), the balance being a solvent (specifically deionized water) and a pH regulator, and the pH value of the dispersion liquid is 4.5; the conductivity of the dispersion liquid is 10.6 ms / cm.

[0087] Example 8

[0088] A dispersion liquid, comprising the following components by mass fraction: 2% of silicon oxide nanoparticles (the silicon oxide nanoparticles are negatively charged with a particle size of 120 nm), 0.5% of ammonium nitrate, 1% of a non-anionic polymer (specifically PVP with a weight-average molecular weight Mw of 2500 g / mol), 0.01% of an anionic polymer (specifically PAA with an Mw of 5000 g / mol), the balance being a solvent (specifically deionized water) and a pH regulator, and the pH value of the dispersion liquid is 4; the conductivity of the dispersion liquid is 11.5 ms / cm.

[0089] Example 9

[0090] A dispersion liquid, comprising the following components by mass fraction: 2% of silica nanoparticles (the silica nanoparticles are negatively charged with a particle size of 120 nm), 0.5% of ammonium nitrate, 0.4% of a non-ionic polymer (specifically PVP with a weight-average molecular weight Mw of 2500 g / mol), 0.01% of an anionic polymer (specifically PAA with an Mw of 800000 g / mol), the balance being a solvent (specifically deionized water) and a pH regulator, and the pH value of the dispersion liquid is 5; the conductivity of the dispersion liquid is 10.8 ms / cm.

[0091] Example 10

[0092] A dispersion liquid, comprising the following components by mass fraction: 2% of silica nanoparticles (the silica nanoparticles are negatively charged with a particle size of 120 nm), 1% of ammonium nitrate, 0.4% of a non-ionic polymer (specifically PVP with a weight-average molecular weight Mw of 2500 g / mol), 0.01% of an anionic polymer (specifically PAA with an Mw of 5000 g / mol), the balance being a solvent (specifically deionized water) and a pH regulator, and the pH value of the dispersion liquid is 4.5; the conductivity of the dispersion liquid is 21.1 ms / cm.

[0093] Comparative Example 1

[0094] A dispersion liquid, comprising the following components by mass fraction: 2% of silica nanoparticles (the silica nanoparticles are negatively charged with a particle size of 120 nm), 0.5% of ammonium nitrate, the balance being a solvent (specifically deionized water) and a pH regulator, and the pH value of the dispersion liquid is 5; the conductivity of the dispersion liquid is 10.0 ms / cm.

[0095] Comparative Example 2

[0096] A dispersion liquid, comprising the following components by mass fraction: 2% of silica nanoparticles (the silica nanoparticles are negatively charged with a particle size of 120 nm), 0.5% of ammonium nitrate, 0.4% of a non-ionic polymer (specifically PVP with a weight-average molecular weight Mw of 2500 g / mol), the balance being a solvent (specifically deionized water) and a pH regulator, and the pH value of the dispersion liquid is 5; the conductivity of the dispersion liquid is 10.2 ms / cm.

[0097] Comparative Example 3

[0098] A dispersion liquid, comprising the following components by mass fraction: 2% of silica nanoparticles (the silica nanoparticles are negatively charged with a particle size of 120 nm), 0.5% of ammonium nitrate, 0.01% of an anionic polymer (specifically PAA with a Mw of 5000 g / mol), the balance being a solvent (specifically deionized water) and a pH regulator, and the pH value of the dispersion liquid is 5; the conductivity of the dispersion liquid is 9.4 ms / cm.

[0099] Comparative Example 4

[0100] A dispersion liquid, comprising the following components by mass fraction: 2% of silica nanoparticles (the silica nanoparticles are negatively charged with a particle size of 120 nm), 1% of a non-anionic polymer (specifically PVP with a weight-average molecular weight Mw of 5000 g / mol), 0.01% of an anionic polymer (specifically PAA with a Mw of 5000 g / mol), the balance being a solvent (specifically deionized water) and a pH regulator, and the pH value of the dispersion liquid is 5; the conductivity of the dispersion liquid is 0.5 ms / cm.

[0101] Grinding test

[0102] The dispersion liquids of each example and comparative example are compounded with an oxidizing agent (specifically H 2 O 2 ) to obtain the grinding compositions of each example and each comparative example, and the mass content of the oxidizing agent in the grinding compositions of each example and comparative example is 1.5%.

[0103] A 12-inch circular wafer is placed on a polishing pad, the polishing pressure is 1.5 psi, the rotation speed of the polishing table is 70 revolutions per minute, the rotation speed of the polishing head is 71 revolutions per minute, and the dropping rate of the grinding compositions of each example and comparative example is 200 ml / min. A commercially available standard metal tungsten and a dielectric control wafer are selected to evaluate the polishing rate. By measuring the thickness difference of the metal film layer before and after polishing within a certain period of time, the polishing rate is calculated. Among them, the selection ratio of the W / dielectric material removal rate is the selection ratio of the W / dielectric material removal rate. The tungsten pattern wafer is used to evaluate the Topology of the wafer after polishing. The height differences after polishing in the 0.18 / 0.18 μm and 1 / 1 μm regions are measured respectively for comparison. The smaller the actual height difference, the better the polishing effect.

[0104] For convenient reading, the parameters of the dispersion liquids of Examples 1 to 8 and Comparative Examples 1 to 3, the selection ratio of the removal rate of the grinding composition for metal tungsten W / dielectric material, and the absolute value of the height difference of the 0.18 / 1 μm line width after polishing are summarized in Table 1.

[0105] Table 1

[0106]

[0107]

[0108]

[0109] Stability Test of Dispersion Liquid

[0110] Take the dispersion liquid of Example 1 and divide it into two groups. Add metal elements to one group, denoted as Comparative Example 1 for Effect, and the other group is not treated, denoted as Example 1 for Effect. Test the content of metal elements in the dispersion liquids of Comparative Example 1 for Effect and Example 1 for Effect. The results are summarized in Table 2. Add 1% hydrogen peroxide to Comparative Example 1 for Effect and Example 1 for Effect respectively, and place them in the dark at room temperature for 7 days. Then test the H 2 O 2 content in the two compositions. Among them, the content of metal elements is tested by ICP-OES, and the H 2 O 2 content is measured by potassium permanganate titration method.

[0111] Table 2

[0112]

[0113] The results show that after standing for 7 days, the H 2 O 2 content of Comparative Example 1 for Effect is 0, and the mass content of H 2 O 2 in Example 1 for Effect is still 1%. This fully shows that the dispersion liquid provided by the embodiments of the present application and the grinding composition provided by it have good stability.

[0114] It should be understood that the first, second, and various numerical numbers involved herein are only for the convenience of description and are not used to limit the scope of the present application.

[0115] In the present application, “and / or” describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character “ / ” generally represents an “or” relationship between the associated objects before and after.

[0116] In this application, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or a similar expression means any combination of these items, including any combination of single item(s) or plural item(s). For example, "at least one of a, b, or c", or "at least one of a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can each be single or plural.

[0117] In this application, "-" represents a range value, including the endpoint values at both ends. For example, if the value range of a is 0.5 - 15, it means the value of a can be between 0.5 and 15, and includes the endpoint values 0.5 and 15.

Claims

1. A dispersion, characterized in that: include: Solvent, inorganic nanoparticles, conductivity regulator, anionic polymer and non-anionic polymer; the conductivity of the dispersion is ≥5ms / cm.

2. The dispersion according to claim 1, characterized in that The conductivity of the dispersion is in the range of greater than 10 ms / cm to less than or equal to 30 ms / cm.

3. The dispersion according to claim 1, characterized in that The conductivity regulator includes ammonium nitrate and / or ammonium sulfate; the conductivity regulator accounts for 0.1%-3% of the mass of the dispersion.

4. The dispersion according to claim 1, characterized in that The anionic polymer includes one or more of polyacrylic acid, polymethacrylic acid, polymaleic acid, maleic acid acrylic acid copolymer, and poly(2-acrylamide-2-methyl-1-propanesulfonic acid); and / or, The non-anionic polymer includes one or more of polyvinyl pyrrolidone, polyacrylamide, poly-N-isopropylacrylamide, and poly-N-vinylacetamide.

5. The dispersion according to claim 1, characterized in that The weight average molecular weight of the anionic polymer is ≤1×10 6 g / mol, the weight average molecular weight of the non-anionic polymer is ≤5×10 4 g / mol.

6. The dispersion according to claim 1, characterized in that The sum of the mass of the anionic polymer and the non-anionic polymer accounts for 0.001%-2% of the mass of the dispersion.

7. The dispersion according to claim 1, characterized in that The pH value of the dispersion is 2-6.

8. The dispersion according to claim 1, characterized in that The dispersion further comprises a pH adjuster; the pH adjuster comprises an inorganic acid, or the pH adjuster comprises an organic amine and / or ammonia water.

9. The dispersion according to claim 1, characterized in that The inorganic nanoparticles include silicon dioxide nanoparticles and / or aluminum oxide nanoparticles; the inorganic nanoparticles account for 0.1% to 5% of the mass of the dispersion.

10. The dispersion according to any one of claims 1 to 9, characterized in that The mass content of the metal element in the dispersion is less than 1 ppm.

11. The dispersion according to any one of claims 1 to 9, characterized in that The solvent includes water.

12. A grinding composition, characterized in that: The invention comprises the dispersion according to any one of claims 1 to 11, and an oxidizing agent; the conductivity of the grinding composition is ≥ 5 ms / cm.

13. The dispersion according to claim 12, characterized in that The oxidant comprises hydrogen peroxide; the oxidant accounts for 0.1%-5% of the mass of the composition.

14. A method for preparing a semiconductor device, characterized in that: include: Placing a semiconductor preform or substrate in a grinding device and opposite to a grinding pad of the grinding device; The polishing composition according to claim 12 or 13 is provided between the semiconductor preform or the substrate and the polishing pad, and the polishing pad is used to polish the semiconductor preform or the substrate.

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