Dispersion, polishing composition and use thereof

Abstract

The application provides a dispersion liquid, a polishing composition and application thereof. 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 5 ms / cm. The dispersion liquid is compounded with an oxidant to obtain a polishing composition, and the polishing composition is particularly suitable for planarization treatment of a structure with both metal tungsten and dielectric material. The planarization effect of the metal tungsten treated by the polishing composition is good, and the Topology of the device surface after polishing can meet the requirements of high-performance semiconductor devices.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor device preparation, and in particular to a dispersion liquid, a polishing composition and application thereof. BACKGROUND

[0002] In the process of semiconductor device, a polishing process is needed to be introduced to realize the planarization of specific area of wafer or semiconductor pre-product in the front-end-of-line process, back-end-of-line process and other stages. In the above-mentioned front-end-of-line process, the semiconductor pre-product often includes the connection of multiple materials, mainly including the connection of metal gate and multiple dielectric materials; and the preparation of metal gate involves polishing to obtain metal gate with ideal height. However, there are multiple film layers composed of silicon nitride, silicon oxide and other materials in the polishing interface of metal gate. In addition, due to the characteristics of semiconductor device, the requirement for the picture topological structure (Topology) of the above-mentioned interface after polishing is strict, so the process window of metal gate polishing is extremely small, and therefore the performance requirement of polishing liquid used in the polishing process is extremely high. Therefore, it is necessary to provide a polishing liquid with relatively optimal comprehensive performance. SUMMARY

[0003] Embodiments of the present application provide a dispersion liquid, a polishing composition and a preparation method of semiconductor device. The dispersion liquid can obtain a polishing composition after compounding with an oxidizing agent, and the polishing composition is especially suitable for planarization treatment of structure with metal tungsten and dielectric material at the same time, the planarization effect of metal tungsten after treatment with the polishing composition is good, and the Topology of device surface after polishing can meet the requirement of high-performance semiconductor device.

[0004] The first aspect of embodiments of the present application provides a dispersion liquid, comprising: a solvent, inorganic nanoparticles, a conductivity regulator, an anionic polymer and a non-anionic polymer; the conductivity of the dispersion liquid is ≥5 ms / cm.

[0005] The stability of the above-mentioned dispersion and the grinding composition obtained after compounding with the oxidant are both excellent, and are suitable for the flattening treatment of structures having both metal tungsten and dielectric materials. In addition, in the chemical environment of the grinding composition obtained after compounding with the oxidant, the inorganic nanoparticles have a better physical grinding effect on metal tungsten, a stable removal rate, and can more flexibly regulate the grinding rate of metal tungsten and dielectric materials, and the regulation range is wide, and the removal selectivity of metal tungsten to dielectric materials can be flexibly regulated within a wide range, and it is conducive to achieving a higher removal selectivity of metal tungsten to dielectric materials, that is, it has a higher compatibility with dielectric materials. In addition, in the dispersion system of the present application and the grinding composition system formed therefrom, an anionic polymer and a non-anionic polymer can form an interpolymer complex and form a surface inhibition layer on the surface of metal tungsten through electrostatic adsorption, slowing down the oxidation rate of the oxidant to metal tungsten, so that the reaction proceeds smoothly, thereby effectively reducing the depression, erosion and defects of metal tungsten after flattening treatment, and improving the electrical properties of the final semiconductor device; In addition, it is also conducive to achieving precise control of the thickness of the ground metal tungsten. Under the synergistic effect of the above factors, in the same workpiece to be planarized, the height difference of metal tungsten with different line widths after planarization is small, and the workpiece after planarization has a better topology, which can effectively improve the performance of the final semiconductor device.

[0006] In some embodiments of the present application, the conductivity of the dispersion is within a range of greater than 10 ms / cm to less than or equal to 30 ms / cm. This further enhances the mechanical action of the inorganic nanoparticles, improves the planarization effect of the metal tungsten, and further increases the removal selectivity of the metal tungsten over the dielectric material.

[0007] In some embodiments of the present application, the conductivity modifier includes ammonium nitrate and / or ammonium sulfate, and the conductivity modifier accounts for 0.1% to 3% of the mass of the dispersion. This further improves the planarization effect of the final abrasive composition on tungsten metal and increases the removal selectivity of tungsten metal over 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 polymer includes one or more of polyvinylpyrrolidone, polyacrylamide, poly-N-isopropylacrylamide, and poly-N-vinylacetamide. In the polishing liquid composition system provided in the embodiments of the present application, these anionic and non-anionic polymers can quickly form relatively stable interpolymer complexes and adsorb onto the surface of the tungsten metal via electrostatic interaction, thereby optimizing the topology of the polishing interface.

[0010] In some embodiments of the present application, 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 This helps to control the viscosity of the dispersion within a relatively low range, thereby facilitating the compounding of the grinding composition and controlling its viscosity within an appropriate range, thereby improving the grinding efficiency and effect.

[0011] In some embodiments of the present application, the combined mass of the anionic polymer and the non-anionic polymer accounts for 0.001%-2% of the mass of the dispersion. This facilitates compounding the dispersion with the oxidant, yielding an abrasive composition with a suitable viscosity. Furthermore, the polymer can be quickly and fully adsorbed onto the surface of the tungsten metal, thereby ensuring a superior planarization effect.

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

[0013] In some embodiments of the present application, the dispersion further comprises a pH adjuster; the pH adjuster comprises an inorganic acid, or an organic amine and / or ammonia. Such pH adjusters are highly compatible with the dispersion and the final polishing composition of the present application, exhibit stable properties, and do not introduce metallic impurity ions.

[0014] In some embodiments of the present application, the inorganic nanoparticles include silicon dioxide nanoparticles and / or aluminum oxide nanoparticles, and the inorganic nanoparticles account for 0.1% to 5% of the mass of the dispersion, thereby improving the overall performance of the dispersion.

[0015] In some embodiments of the present application, the mass content of the metal element in the dispersion is less than 1 ppm. This can reduce or even avoid the decomposition of the oxidant due to the presence of free metal ions in the final abrasive composition, and can also reduce or avoid the risk of metal ions remaining on the surface of the device after planarization.

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

[0017] A second aspect of the embodiments of the present application provides an abrasive composition, comprising the aforementioned dispersion provided in the embodiments of the present application, and an oxidant; the conductivity of the abrasive composition is ≥5 ms / cm.

[0018] In the grinding combination provided by the present application, the physical grinding effect of inorganic nanoparticles on metal tungsten is better, the removal rate is stable, and the grinding rate of metal tungsten and dielectric materials can be regulated more flexibly, with a wide control range, and a higher removal selectivity of metal tungsten to dielectric materials can be achieved, that is, the compatibility with dielectric materials is higher. In addition, in the grinding composition system of the present application, anionic polymers and non-anionic polymers can form an interpolymer complex and form a surface inhibition layer on the surface of metal tungsten through electrostatic adsorption, slowing down the oxidation rate of metal tungsten by the oxidant, so that the reaction proceeds smoothly, thereby effectively reducing the depression, erosion and defects of metal tungsten after flattening treatment, and improving the electrical properties of the final semiconductor device; in addition, it is also conducive to achieving precise control of the thickness of the ground metal tungsten. Under the synergistic effect of the above factors, in the same workpiece to be flattened, the grinding composition provided by the embodiment of the present application is simultaneously applicable to the flattening treatment of structures having metal tungsten and dielectric materials, and the height difference of metal tungsten with different line widths after flattening treatment is small, and the workpiece after flattening treatment has a better Topology, thereby effectively improving the performance of the final semiconductor device.

[0019] In some embodiments of the present application, the oxidizing agent includes hydrogen peroxide, which accounts for 0.1% to 5% by weight of the composition. In the polishing composition system of the present application, hydrogen peroxide can slowly oxidize the surface of the tungsten metal, thereby facilitating the production of high-quality tungsten metal gates. Controlling the oxidizing agent's mass percentage within the aforementioned range can improve the performance of the resulting device.

[0020] The present invention also provides a method for preparing a semiconductor device, comprising:

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

[0022] The polishing composition provided in the embodiment of the present application is provided between the semiconductor preform or substrate and the polishing pad, so that the polishing pad polishes the semiconductor preform or substrate.

[0023] The preparation method of the semiconductor device provided by the embodiments of the present application has strong process reliability and is suitable for large-scale industrial production. In addition, the above preparation method can be used to prepare high-precision chips and other semiconductor devices with high integration due to the use of the polishing composition provided by the embodiments of the present application, and the semiconductor devices prepared therefrom have better performance and high yield. DETAILED DESCRIPTION

[0024] With the continuous reduction of the size of semiconductor devices, the traditional polysilicon gate structure faces many challenges. For example, the gate leakage is too large, and it is difficult to accurately control the threshold voltage. In order to overcome the above problems, the metal gate system is used to replace the original polysilicon gate system in the related art. The metal gate can be a metal tungsten gate, for example. In the preparation process of the semiconductor device, the preparation of the metal gate generally includes: sequentially depositing a dielectric material and a gate metal on a specific region of the substrate surface, and then performing a planarization treatment on the workpiece to be planarized on which the gate metal is deposited, to obtain a metal gate with a target height and a target topography, and a polishing interface with a better Topology. In addition, the above workpiece to be planarized often involves the connection of multiple materials, including gate metal, dielectric material, etc. Taking tungsten as the gate metal as an example, the materials connected therewith can include silicon nitride, silicon oxide and other dielectrics, for example. Specifically, the metal tungsten is deposited in the opening formed by the dielectric material layer. After deposition, the excess tungsten metal on the dielectric material needs to be removed by polishing to form a metal gate in the dielectric layer. Therefore, in the polishing process, it is often necessary to remove the metal tungsten with high selectivity. That is, the metal tungsten and the dielectric material exhibit different polishing removal rates.

[0025] Lapping generally involves placing the workpiece to be planarized on a lapping pad in a lapping machine, providing an abrasive composition between the pad and the surface of the workpiece, and moving the pad and the workpiece relative to each other. The properties of the abrasive composition significantly influence dielectric layer erosion, metal gate recessing, defect generation, and polishing removal selectivity during the planarization process. Furthermore, even with the same material, the surface to be planarized may contain regions of varying line widths. These regions often exhibit height differences after lapping, which can affect semiconductor device performance. Reducing these height differences is a key area of ​​focus in the industry. The smaller the height difference, the better the topology of the polishing interface. In some cases, the lapping composition typically includes an oxidizing agent. To maintain the stability of the lapping composition, the oxidizing agent is typically compounded with the other components of the lapping composition (i.e., the dispersion) before use. The properties of the lapping composition, or dispersion, are crucial factors in determining the effectiveness of the planarization process. In the prior art, tungsten polishing slurries typically use hydrogen peroxide as an oxidant, supplemented by ferric nitrate as a catalyst to planarize the tungsten metal. Specifically, the chemical reaction between iron and hydrogen peroxide generates highly oxidizing hydroxyl radicals, which oxidize the tungsten metal to easily removable tungsten trioxide (WO3). Nanoparticles then mechanically remove this oxide, resulting in suboptimal planarization. Therefore, there is an urgent need for a dispersion and polishing composition with superior overall performance.

[0026] The present embodiment provides a dispersion comprising: a solvent, inorganic nanoparticles, a conductivity modifier, an anionic polymer, and a non-anionic polymer; the dispersion has a conductivity of ≥5 ms / cm. In the embodiments of the present application, an anionic polymer refers to a polymer whose molecular chains exhibit anionic properties when dispersed in a high dielectric medium such as water.

[0027] The above-mentioned dispersion and the polishing composition obtained after compounding with the oxidant have excellent stability and are suitable for the flattening treatment of structures having both metal tungsten and dielectric materials. Specifically, the conductivity of the dispersion provided in the present application is ≥5 ms / cm. In the chemical environment of the polishing composition formed after compounding with the oxidant, the oxidant can effectively oxidize the surface layer of the metal tungsten and form an oxide film layer on the surface of the metal tungsten. The inorganic nanoparticles can remove the above-mentioned oxide film layer with the assistance of mechanical action, thereby achieving the flattening of the metal tungsten through the dual action of chemical and physical action. In addition, in the chemical environment of the above-mentioned conductivity, the inorganic nanoparticles have a better physical polishing effect on metal tungsten, a stable removal rate, and can more flexibly control the polishing rate of metal tungsten and dielectric materials (including silicon nitride, silicon oxide, silicon oxynitride and other materials), and the control range is wide. The removal selectivity of metal tungsten to dielectric materials can be flexibly controlled within a wide range, and it is conducive to achieving a higher removal selectivity of metal tungsten to dielectric materials, that is, it has high compatibility with dielectric materials. In addition, in the dispersion system and polishing composition system of the present application, the anionic polymer and the non-anionic polymer can form an interpolymer complex and form a surface inhibition layer on the surface of the metal tungsten through electrostatic adsorption, slowing down the oxidation rate of the metal tungsten by the oxidant and making the reaction proceed smoothly, thereby effectively reducing the pitting, erosion and defects of the metal tungsten after the 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 metal tungsten (when the polishing object is the gate metal, it is beneficial to control 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 the metal tungsten with different line widths after the planarization treatment is small (similarly, the height difference of the metal gates with different line widths is small), and the workpiece after the planarization treatment has a better topology, which can effectively improve the performance of the final semiconductor device. In addition, the dispersion provided by the embodiment of the present application still has high stability under high conductivity. It should be noted that the removal selectivity of metal tungsten to dielectric material = metal tungsten removal rate / dielectric material removal rate. In some embodiments of the present application, the removal selectivity of metal tungsten to dielectric material is ≥15; for example, ≥20, ≥25, or ≥30. Specifically, the removal selectivity of metal tungsten to dielectric material 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 of the embodiment of the present application can be used to provide a polishing liquid with a high metal tungsten / dielectric material removal selectivity, but the metal tungsten / dielectric material removal selectivity of the final polishing liquid is not limited to be greater than or equal to 15; in some special application scenarios, the metal tungsten / dielectric material removal selectivity can also be controlled within the desired range by further fine-tuning the components.

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

[0030] In the embodiment of the present application, the conductivity of the dispersion 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 conductivity is too low (<5 ms / cm), the removal rate of the final polishing composition on the wafer surface may be too low.

[0031] In the embodiments of the present application, the presence of the non-anionic polymer and the anionic polymer in the dispersion is tested, including but not limited to, using nuclear magnetic resonance.

[0032] In some embodiments of the present application, the conductivity of the dispersion is in the range of 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, the conductivity of the dispersion is controlled within the above range. When it is compounded with an oxidant to form a grinding composition, it can further promote the mechanical action of the inorganic nanoparticles, further enhance the flattening effect of the metal tungsten, and be more conducive to reducing the height difference of the metal tungsten with different line widths after the flattening treatment, optimizing the topology after flattening, and being 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, or 30 ms / cm. For convenience of description, the conductivity of the dispersion is denoted as X, 10 ms / cm <X≤30ms / 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 of the embodiment of the present application and the final grinding composition, and will not have a negative effect on the leveling process, and the above two substances can flexibly adjust the conductivity of the dispersion to the range recommended by the present application, and even at high conductivity (for example, 20ms / cm-30ms / cm), it still has a high solution stability and will not gel. The grinding composition obtained after long-term storage at room temperature and compounding with the oxidizing solution still has relatively excellent grinding performance. With the cooperation of the above-mentioned conductivity regulator, non-ionic polymer, and anionic polymer, in the dispersion system of the embodiment of the present application, it is possible to reduce the height difference of metal tungsten with different line widths while improving the selective removal ratio of metal tungsten to dielectric materials. In some specific embodiments, the grinding composition obtained by compounding the dispersion and the oxidant has a height difference of ≤15 nm after grinding the 0.18 / 0.18 μm metal tungsten and the 1 / 1 μm area, 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 embodiment of the present application, the presence of the conductivity regulator is detected by testing the anions and cations in the dispersion using an ion chromatograph, but not limited to.

[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 within the range recommended by the present application, thereby being more conducive to improving the planarization effect of the final grinding composition on metal tungsten and being more conducive to improving the removal selectivity of metal tungsten to dielectric materials. 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% of the mass of the dispersion. In the embodiments of the present application, the mass ratio of the conductivity regulator in the dispersion is tested, 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-acrylamide-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-vinyl acetamide (PNVA). The above-mentioned anionic polymers and non-anionic polymers can quickly form relatively stable interpolymer complexes in the system of the polishing liquid composition provided in the embodiments of the present application and be adsorbed on the surface of the metal tungsten through electrostatic action, thereby being more conducive to slowing down the oxidation reaction of the metal tungsten, effectively reducing the depression and erosion of the metal tungsten after grinding, and optimizing the topology of the grinding interface.

[0037] In some embodiments of the present application, the sum of the mass of the above-mentioned anionic polymer and non-anionic polymer accounts for 0.001%-2% of the mass of the dispersion. In this way, when performing a planarization treatment, the aforementioned surface inhibition layer of appropriate thickness can be quickly and fully attached to the surface of the metal tungsten, controlling the oxidation reaction of the metal tungsten within a relatively optimal range; it is also beneficial to control the viscosity of the dispersion within a suitable range, which is beneficial for compounding it with the oxidant to obtain a grinding composition with appropriate viscosity, thereby ensuring a better planarization treatment effect. Specifically, the sum of the mass of the above-mentioned anionic polymer and 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% of the mass of the dispersion. In the embodiments of the present application, gel permeation chromatography is used to test the mass proportions of anionic polymers and non-anionic polymers in the dispersion, but is not limited thereto.

[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). This facilitates the rapid attachment of the polymer intermolecular complex to the surface of the metal tungsten during the planarization process. 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 is less than 1×10 6 g / mol, weight average molecular weight of non-anionic polymer Mw≤5×10 4g / mol. In this way, it is beneficial to control the viscosity of the dispersion within a lower range, thereby facilitating the compounding of the grinding composition and controlling its viscosity within an appropriate range, thereby helping to improve the efficiency and effect of grinding and 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 embodiment 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, or 50000 g / mol. In the embodiment of the present application, the weight average molecular weight Mw of the anionic polymer and the non-anionic polymer can be tested, including but not limited to, by gel permeation chromatography (GPC).

[0040] In some embodiments of the present application, the dispersion further comprises a pH adjuster. It is appreciated that the pH adjuster is used to adjust the pH value of the dispersion. In some embodiments of the present application, the pH value of the dispersion is in the range of 2-6. Controlling the pH value of the dispersion in the range of 2-6 is beneficial for optimizing the planarization effect and is more beneficial for achieving the removal selectivity of tungsten metal to dielectric material. Specifically, the pH value of the dispersion 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 embodiments of the present application, the pH value of the dispersion is tested by a pH meter, but is not limited thereto.

[0041] In some embodiments of the present application, the pH adjuster comprises an inorganic acid, or the pH adjuster comprises an organic amine and / or ammonia. In embodiments of the present application, the 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 adjuster is beneficial for its adaptation to the planarization of tungsten metal and dielectric layer. In embodiments of the present application, the organic amine can be, for example, an alkyl amine, aniline, naphthylamine, but is not limited thereto. Specifically, the alkyl amine can be, for example, R3-NH2, R4-NH-R5, wherein R3, R4, R5 are each independently an alkyl group; the alkyl group can be, for example, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, etc.; the alkyl amine can be, for example, one or more of diethylamine, triethylamine, di-n-propylamine, n-butylamine, etc. In some specific embodiments, the pH adjuster comprises ammonia. In embodiments of the present application, the pH adjuster has good compatibility with the dispersion and the final polishing composition of the present application, has stable properties, and does not introduce metal impurity ions. It is appreciated that in some embodiments, the adjuster is an inorganic acid, which is more beneficial for adjusting the dispersion and the polishing composition to a pH value of 2; in this way, it is more beneficial for improving the polishing rate of the polishing composition to tungsten metal. In other embodiments, the adjuster is an organic amine and / or ammonia, which is more beneficial for adjusting the dispersion and the polishing composition to a pH value of 6; in this way, the influence on the surface potential of crystalline silicon, silicon nitride, etc. is more obvious, and it is more beneficial for improving the Topology of the device after polishing.

[0042] As semiconductor devices shrink, the requirements for planarization in semiconductor device manufacturing processes are becoming increasingly stringent. The abrasive compositions used in related art contain relatively large amounts of metal ions, which exhibit strong chemical oxidation during the planarization of tungsten, resulting in a high oxide production rate and a rapid removal rate. However, excessive chemical oxidation can cause a large amount of corrosion, pitting, and defective structures to form on the surface of the metal tungsten, and there is a high risk of metal ions remaining on the surface of the device after planarization. All of these factors can affect device performance and the yield of semiconductor devices. Furthermore, metal ions can accelerate the decomposition of oxidants such as hydrogen peroxide, affecting the planarization effect. In some embodiments of the present application, the mass content of the metal element in the dispersion is less than 10 ppm. In some specific embodiments, the mass content of the metal element in the dispersion is less than or equal to 1 ppm. In some specific embodiments, the content of the metal element in the dispersion approaches zero, or even zero. This can reduce or even avoid the decomposition of the oxidant due to the presence of free metal ions in the final abrasive composition, and can also reduce or avoid the risk of metal ions remaining on the device surface after planarization. Specifically, the above-mentioned 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 is tested, including but not limited to, using inductively coupled plasma mass spectrometry (ICP-MS) or inductively coupled plasma atomic emission spectrometry (ICP-OES).

[0044] In 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 the nanoparticles in solution as measured by dynamic light scattering. It is a hydrodynamic diameter that represents the size of the nanoparticles in solution due to diffusion behavior. The hydrated particle size includes the solvent layer bound to the nanoparticle surface or other molecules that move with the particle, and is therefore 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, e.g., 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 of the aforementioned hydrated particle size exhibit excellent polishing effects on metallic tungsten. Specifically, they achieve high tungsten removal efficiency and are less likely to cause scratches on the surface being leveled (i.e., the workpiece being polished). Furthermore, the inorganic nanoparticles of the aforementioned size are easily evenly distributed in the dispersion, facilitating the formation of a uniform abrasive composition. In embodiments of the present application, the presence and morphology of the inorganic nanoparticles can be observed using a scanning electron microscope (SEM) coupled with an energy dispersive spectrometer (EDS). In embodiments of the present application, the particle size of the inorganic nanoparticles can be measured, for example, using a laser particle size analyzer.

[0045] In some embodiments of the present application, the inorganic nanoparticles may be electrically neutral, or may be positively 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 is <0. In some embodiments of the present application, the zeta potential of the inorganic nanoparticles may be measured, including but not limited to, using a zeta potential meter.

[0046] In some embodiments of the present application, the inorganic nanoparticles account for 0.1%-5% of the mass of the dispersion. This is beneficial to the comprehensive performance of the dispersion. Specifically, the mass proportion 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, the mass proportion of the inorganic nanoparticles in the dispersion is tested, including but not limited to, by thermogravimetric analysis (TGA).

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

[0048] In some embodiments of the present application, the preparation of the dispersion comprises: mixing inorganic nanoparticles, a conductivity modifier, an anionic polymer, and a non-anionic polymer in a solvent. In some specific embodiments, the preparation of the dispersion comprises: uniformly mixing the inorganic nanoparticles, the conductivity modifier, anionic polymer, and non-anionic polymer in a solvent, and then adding a pH modifier to adjust the pH of the mixture to a target value to obtain the dispersion. In some embodiments of the present application, a sol containing inorganic nanoparticles may be directly added to the solvent; for example, silica sol, specifically an aqueous dispersion of silica nanoparticles.

[0049] The present embodiment also provides a grinding composition, comprising the aforementioned dispersion provided in the present embodiment, and an oxidizing agent; the conductivity of the grinding composition is ≥5 ms / cm.

[0050] In the abrasive composition provided by the present application, the physical grinding effect of inorganic nanoparticles on metal tungsten is better, the removal rate is stable, and the grinding rate of metal tungsten and dielectric materials can be regulated more flexibly, with a wide regulation range, and a higher removal selectivity of metal tungsten to dielectric materials can be achieved, that is, the compatibility with dielectric materials is higher. In addition, in the abrasive composition system of the present application, anionic polymers and non-anionic polymers can form an interpolymer complex and form a surface inhibition layer on the surface of metal tungsten by electrostatic adsorption, slowing down the oxidation rate of metal tungsten by the oxidant, so that the reaction proceeds smoothly, thereby effectively reducing the depression, erosion and defects of metal tungsten after flattening treatment, and improving the electrical properties of the final semiconductor device; in addition, it is also conducive to achieving precise control of the thickness of the metal tungsten after grinding. Under the synergistic effect of the above factors, in the same workpiece to be flattened, the abrasive composition provided by the embodiment of the present application is simultaneously applicable to the flattening treatment of structures having metal tungsten and dielectric materials, and the height difference of metal tungsten with different line widths after flattening treatment is small, and the workpiece after flattening treatment has a better Topology, thereby effectively improving the performance of the final semiconductor device.

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

[0052] In some embodiments of the present application, the conductivity of the polishing composition is in the range of greater than 10 ms / cm to less than or equal to 30 ms / cm.

[0053] In some embodiments of the present application, the conductivity of the polishing composition is in the range of 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 comprises hydrogen peroxide H2O2. In the system of the polishing composition of the present application, the hydrogen peroxide can slowly oxidize the surface of the metal tungsten to convert it into a softened WO4 2- layer, which is easier to remove, thereby also facilitating the obtaining of high-quality tungsten metal gates. 2-

[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 percentage of the oxidizing agent in the above range facilitates controlling the oxidation rate of the metal tungsten in a relatively gentle and stable range during the planarization of the metal tungsten, thereby more facilitating the planarization effect of the metal tungsten and facilitating the performance of the final device. Specifically, the mass percentage 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 percentage of the hydrogen peroxide in the polishing composition is 0.1%-5%. In embodiments of the present application, the mass content of the hydrogen peroxide in the polishing composition can be tested by using 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 polishing composition. In some specific embodiments, the conductivity regulator accounts for 0.1%-3% of the mass of the polishing composition. Specifically, the conductivity regulator can account for 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% of the mass of the polishing composition, for example. In embodiments of the present application, ion chromatography can be used to test the mass percentage of the conductivity regulator in the polishing composition.

[0057] In some embodiments of the present application, the inorganic nanoparticles account for 0.095%-5% of the mass of the polishing composition. In some specific embodiments, the inorganic nanoparticles account for 0.1%-5% of the mass of the polishing composition. Specifically, the inorganic nanoparticles can account for 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% of the mass of the polishing composition, for example. In embodiments of the present application, TGA can be used to test the mass percentage of the inorganic nanoparticles in the polishing composition.

[0058] In some embodiments of the present application, the pH value of the polishing composition is 2-6. This is conducive to optimizing the planarization effect and is more conducive to achieving the adjustment of the removal selectivity ratio of tungsten metal to dielectric material. Specifically, the pH value of the polishing composition can be 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 embodiments of the present application, the pH value of the polishing composition is tested by a pH meter, but is not limited thereto.

[0059] In some embodiments of the present application, the combined mass of the anionic polymer and the non-anionic polymer accounts for 0.00095%-2% of the mass of the abrasive composition. In some specific embodiments, the combined mass of the anionic polymer and the non-anionic polymer accounts for 0.001%-2% of the mass of the abrasive composition. This helps control the oxidation reaction of the tungsten metal within an optimal range and also helps control the viscosity of the abrasive composition within a suitable range, thereby ensuring a better planarization effect. Specifically, the sum of the mass of the anionic polymer and the non-anionic polymer can be, for example, 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% of the mass of the dispersion. In the embodiment of the present application, gel permeation chromatography can be used to test the mass proportions of the anionic polymer and the non-anionic polymer in the abrasive composition.

[0060] In some embodiments of the present application, the mass content of the metal element in the abrasive composition is less than 10 ppm. In some specific embodiments, the mass content of the metal element in the abrasive composition is less than or equal to 1 ppm. In some specific embodiments, the mass content of the metal element in the abrasive composition approaches zero, or even is zero. For details, please refer to the description of the metal element content in the dispersion above, which will not be repeated here.

[0061] The present application also provides a planarization method, including:

[0062] The abrasive composition provided in the embodiments of the present application is used to contact the surface of an object to be planarized with the abrasive composition and move the object relative to the surface. In some embodiments, the surface of the object to be planarized comprises metallic tungsten; further, the object to be planarized comprises both metallic tungsten and the aforementioned dielectric material.

[0063] In the process of the flattening method provided in the embodiments of the present application, a polishing pad is placed flat on a polishing table, an object to be flattened is fixed to the polishing head, and the surface to be polished of the object to be flattened is brought into contact with the polishing pad, which is then pressed against the polishing pad with a certain pressure. During the flattening process, the polishing head rotates with the object to be flattened, and the polishing table also rotates at a certain speed; at the same time, an abrasive composition is added to the polishing pad at a certain rate and spreads on the polishing pad due to centrifugal force. Under the dual action of chemical and mechanical forces, the object to be flattened achieves the flattening of the metal tungsten, resulting in a polished surface with a better topology.

[0064] After the planarization process, a cleaning process may be performed to remove abrasives and other substances remaining on the surface of the ground object.

[0065] The present invention also provides a method for preparing a semiconductor device, comprising:

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

[0067] The polishing composition provided in the embodiment of the present application is provided between the semiconductor preform or substrate and the polishing pad, so that the polishing pad polishes the semiconductor preform or substrate.

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

[0069] In an embodiment of the present application, the polishing composition provided in the embodiment of the present application is provided between the semiconductor preform or substrate and the polishing pad, and the polishing pad is used to polish the semiconductor preform or substrate, comprising:

[0070] The polishing pad is placed flat on the polishing table. A semiconductor preform or substrate is secured to the polishing head, with the surface to be polished in contact with the polishing pad. The polishing pad is then pressed against the polishing pad with a certain pressure. During the polishing (planarization process), the polishing head rotates with the semiconductor preform or substrate, and the polishing table also rotates at a certain speed. Simultaneously, the abrasive composition is added to the polishing pad at a certain rate and spreads across the pad due to centrifugal force. This dual action of chemical and mechanical flattening of the tungsten metal on the semiconductor preform or substrate produces a polished surface with superior topology.

[0071] The preparation method of the semiconductor device provided by the embodiments of the present application has strong process reliability and is suitable for large-scale industrial production. Meanwhile, the preparation method can be used to prepare high-precision chips and other semiconductor devices with high integration due to the use of the grinding composition provided by the embodiments of the present application, and the semiconductor device prepared by the method has better performance and a high yield.

[0072] The technical solutions of the present application are further described in the following embodiments.

[0073] Embodiment 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 non-anionic polymer (specifically, PVP with a weight average molecular weight Mw of 2500 g / mol), 0.05% of an anionic polymer (specifically, PAA with a Mw of 5000 g / mol), the balance of a solvent (specifically, deionized water), and a pH adjuster, and the pH value of the dispersion liquid is 5; the conductivity of the dispersion liquid is 9.8 ms / cm.

[0075] Embodiment 2

[0076] A dispersion liquid, which is different from Embodiment 1 in that the mass fraction of conductivity adjustment in the dispersion liquid is adjusted to 0.4%; the conductivity of the dispersion liquid is 8.5 ms / cm.

[0077] Embodiment 3

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

[0079] Embodiment 4

[0080] A dispersion liquid, which is different from Embodiment 1 in that the mass fraction 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] Embodiment 5

[0082] A dispersion comprises the following components in weight fractions: 2% of silicon oxide nanoparticles (the silicon oxide nanoparticles are negatively charged and have 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 a Mw of 3000 g / mol), the remainder being a solvent (specifically, deionized water) and a pH adjuster. The pH value of the dispersion is 5, and the conductivity of the dispersion is 10.2 ms / cm.

[0083] Example 6

[0084] A dispersion comprises the following components in weight fractions: 2% silicon oxide nanoparticles (the silicon oxide nanoparticles are negatively charged and have a particle size of 120 nm), 0.5% ammonium nitrate, 0.4% a non-anionic polymer (specifically, PVP with a weight-average molecular weight (Mw) of 2500 g / mol), 0.01% anionic polymer (specifically, HPMA polymaleic acid with a Mw of 2000 g / mol), the remainder a solvent (specifically, deionized water) and a pH adjuster. The pH value of the dispersion is 5, and the conductivity of the dispersion is 10.5 ms / cm.

[0085] Example 7

[0086] A dispersion comprises the following components in weight fractions: 2% silicon oxide nanoparticles (the silicon oxide nanoparticles are negatively charged and have a particle size of 120 nm), 0.5% ammonium nitrate, 0.8% a non-anionic polymer (specifically, PVP with a weight-average molecular weight (Mw) of 2500 g / mol), 0.01% anionic polymer (specifically, PAA with a Mw of 5000 g / mol), the remainder a solvent (specifically, deionized water) and a pH adjuster, wherein the pH value of the dispersion is 4.5; and the conductivity of the dispersion is 10.6 ms / cm.

[0087] Example 8

[0088] A dispersion comprises the following components in weight fractions: 2% silicon oxide nanoparticles (the silicon oxide nanoparticles are negatively charged and have a particle size of 120 nm), 0.5% ammonium nitrate, 1% a non-anionic polymer (specifically, PVP with a weight-average molecular weight (Mw) of 2500 g / mol), 0.01% anionic polymer (specifically, PAA with a Mw of 5000 g / mol), the remainder being a solvent (specifically, deionized water) and a pH adjuster. The pH value of the dispersion is 4, and the conductivity of the dispersion is 11.5 ms / cm.

[0089] Example 9

[0090] A dispersion liquid comprising the following components in mass fraction: 2% of silica nanoparticles (the silica nanoparticles are negatively charged, and the particle size is 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, PAA with a Mw of 800000 g / mol), the balance being a solvent (specifically, deionized water), and a pH adjuster, 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 in mass fraction: 2% of silica nanoparticles (the silica nanoparticles are negatively charged, and the particle size is 120 nm), 1% 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, PAA with a Mw of 5000 g / mol), the balance being a solvent (specifically, deionized water), and a pH adjuster, 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 in mass fraction: 2% of silica nanoparticles (the silica nanoparticles are negatively charged, and the particle size is 120 nm), 0.5% of ammonium nitrate, the balance being a solvent (specifically, deionized water), and a pH adjuster, 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 in mass fraction: 2% of silica nanoparticles (the silica nanoparticles are negatively charged, and the particle size is 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), the balance being a solvent (specifically, deionized water), and a pH adjuster, 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, and the particle size is 120 nm), 0.5% of ammonium nitrate, 0.01% of an anionic polymer (specifically PAA with a weight average molecular weight Mw of 5000 g / mol), the balance of a solvent (specifically deionized water), and a pH adjuster, 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, and the particle size is 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 weight average molecular weight Mw of 5000 g / mol), the balance of a solvent (specifically deionized water), and a pH adjuster, and the pH value of the dispersion liquid is 5; the conductivity of the dispersion liquid is 0.5 ms / cm.

[0101] Polishing test

[0102] The dispersion liquids of the examples and comparative examples were compounded with an oxidizing agent (specifically H2O2) to obtain polishing compositions of the examples and comparative examples, and the mass content of the oxidizing agent in the polishing compositions of the examples and comparative examples was 1.5%.

[0103] A 12-inch circular wafer was placed on a polishing pad, the polishing pressure was 1.5 psi, the polishing table rotation speed was 70 revolutions / minute, the polishing head rotation speed was 71 revolutions / minute, and the drop speed of the polishing compositions of the examples and comparative examples was 200 milliliters / minute. Commercially available standard metal tungsten and dielectric control sheets were selected to evaluate the polishing rate, and the polishing rate was calculated by measuring the thickness difference of the metal film layer before and after polishing within a certain time. Among them, the W / dielectric material removal rate selection ratio was selected. The tungsten pattern sheet was used to evaluate the Topology of the polished wafer, and the height difference after polishing in the 0.18 / 0.18 μm and 1 / 1 μm areas was measured and compared, and the smaller the actual height difference, the better the polishing effect.

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

[0105] Table 1

[0106]

[0107] Stability test of dispersion

[0108] The dispersion of Example 1 was divided into two groups, one of which was added with metal elements, denoted as effect comparative example 1, and the other was not treated, denoted as effect example 1. The content of metal elements in the dispersion of effect comparative example 1 and effect example 1 was tested, and the results are summarized in Table 2. 1% hydrogen peroxide was added to effect comparative example 1 and effect example 1 respectively, and the content of H2O2 in the two compositions was tested after 7 days of storage at room temperature in the dark. Among them, the content of metal elements was tested by ICP-OES, and the content of H2O2 was measured by potassium permanganate titration method.

[0109] Table 2

[0110]

[0111] The results show that the content of H2O2 in effect comparative example 1 is 0 after 7 days of standing, and the mass content of H2O2 in effect example 1 is still 1%. It fully illustrates that the dispersion provided by the embodiments of the application and the polishing composition provided by the embodiments of the application have good stability.

[0112] It should be understood that the first, second, and various numerical numbers referred to herein are only for the convenience of differentiation, and do not limit the scope of the application.

[0113] In the present application, "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can mean that A exists alone, A and B exist together, 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 it.

[0114] In the present application, "at least one" means one or more, and "multiple" means two or more. "At least one of the following" or the like means any combination of these items, including any combination of single item or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can mean a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0115] In the present application, "-" represents a range value, including the end point values at both ends, for example, the value of a can be 0.5-15, which means that the value of a can be between 0.5 and 15, and includes the end point 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 ≥6 ms / cm 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); The non-anionic polymer includes one or more of polyvinylpyrrolidone, polyacrylamide, poly-N-isopropylacrylamide, and poly-N-vinylacetamide; The pH value of the dispersion is 2-6.

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

3. The dispersion according to claim 1, wherein 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, wherein 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.

5. 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.

6. The dispersion according to claim 1, wherein The dispersion further includes a pH adjuster; the pH adjuster includes an inorganic acid, or the pH adjuster includes an organic amine and / or ammonia water.

7. The dispersion according to claim 1, wherein 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.

8. The dispersion according to any one of claims 1 to 7, characterized in that The mass content of the metal element in the dispersion is less than 1 ppm.

9. The dispersion according to any one of claims 1 to 7, characterized in that The solvent includes water.

10. A grinding composition, characterized in that The method comprises the dispersion according to any one of claims 1 to 9, and an oxidizing agent; wherein the conductivity of the grinding composition is ≥ 6 ms / cm.

11. The abrasive composition according to claim 10, wherein The oxidant includes hydrogen peroxide; the oxidant accounts for 0.1%-5% of the mass of the composition.

12. A method for preparing a semiconductor device, characterized in that: include: placing the semiconductor preform or substrate in a grinding device and opposite to the grinding pad of the grinding device; The polishing composition according to claim 10 or 11 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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