Hafnium precursor material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of semiconductor materials, and particularly relates to a hafnium precursor material and a preparation method and application thereof. The hafnium precursor material has a structure as shown in a formula (1). The hafnium precursor material with a specific structure is designed and synthesized, and the molecular structure of the hafnium precursor material contains an alkylene dicyclopentadienyl organic group structure, so that compared with an existing cyclopentadienyl hafnium precursor material (such as cyclopentadienyl) tris (dimethylamino) hafnium), the hafnium precursor material has higher thermal stability, and meanwhile, the hafnium precursor material can be used for preparing a hafnium precursor material. The viscosity is low, the film yield is improved, and the performance of the film prepared from the raw material is better. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor materials, and in particular relates to a hafnium-based precursor material and a preparation method and application thereof. Background Art

[0002] Semiconductor precursors are core manufacturing materials for thin-film deposition processes and are primarily used in semiconductor storage, capacitor electrodes, gate transition layers, and isolation materials for logic chips. In the NAND FLASH field, as the number of NAND stacking layers continues to increase, precursor usage is rapidly increasing. In the DRAM field, as DRAM develops toward higher aspect ratios, High-K precursors with higher unit value are required. In the logic chip field, as the line width of logic chips becomes finer, more precursor varieties are used, and the product value increases. Metal-based hafnium precursor compounds hold a crucial position, primarily due to their high process reliability and high volatility. Metal-based hafnium precursor compounds, as organometallic compounds, consist of a central metal and its ligands. Currently, cyclopentadienyl ligands are commonly used to coordinate with hafnium metal to form precursor materials. However, these existing hafnium precursor materials generally suffer from high viscosity and low film yield, which can affect film quality. Summary of the Invention

[0003] One of the purposes of the present invention is to address the problem that existing metal-based hafnium precursor compounds have high viscosity and low film yield, thereby reducing film quality, and to provide a hafnium precursor material that not only has good thermal stability but also has low viscosity and high film yield.

[0004] Specifically, the hafnium-based precursor material has a structure as shown in formula (1):

[0005]

[0006] In formula (1), R1 is an alkylene group having 1 to 5 carbon atoms, and R2 and R3 are each independently an alkyl group having 1 to 5 carbon atoms.

[0007] In a preferred embodiment, the hafnium precursor material is selected from at least one of the compounds having the structures shown in formulas (1-1) to (1-6):

[0008]

[0009] A second object of the present invention is to provide a method for preparing the hafnium-based precursor material. The preparation method comprises the following steps:

[0010] S1. performing a first reaction of cyclopentadiene with a metal hydride in the presence of a first organic solvent to obtain a metallated cyclopentadiene of formula (2);

[0011] S2. performing a second reaction of the metallated cyclopentadiene with the alkyl halide compound represented by formula (3) in the presence of a second organic solvent to obtain an intermediate product I represented by formula (4);

[0012] S3. The intermediate product Ⅰ is reacted with sodium metal in the presence of a third organic solvent to obtain an intermediate product Ⅱ shown in formula (5);

[0013] S4. performing a third reaction of the intermediate product II with a hafnium halide in the presence of a fourth organic solvent to obtain an intermediate product III represented by formula (6);

[0014] S5. alkoxylating the intermediate product III with an alkali metal alcohol compound and / or an alcohol compound in the presence of a fifth organic solvent to obtain a hafnium precursor material represented by formula (1);

[0015]

[0016]

[0017] In formulas (2) to (6), Y is selected from at least one of sodium, potassium, lithium, calcium, and copper; R1 is an alkylene group having 1 to 5 carbon atoms; X is selected from a chlorine atom, a bromine atom, and an iodine atom; and the hafnium halide is selected from at least one of hafnium tetrafluoride, hafnium tetrachloride, hafnium tetrabromide, and hafnium tetraiodide.

[0018] In a preferred embodiment, in step S1, the metal hydride is selected from at least one of sodium hydride, potassium hydride, lithium hydride, and lithium aluminum hydride.

[0019] In a preferred embodiment, in step S1, the molar ratio of cyclopentadiene to metal hydride is 1:(1.0-1.5).

[0020] In a preferred embodiment, in step S1, the conditions of the first reaction include: an inert gas atmosphere, a temperature of -50 to -30°C, and a time of 0.5 to 2 hours.

[0021] In a preferred embodiment, in step S2, the halogenated alkyl compound is selected from at least one of 1,3-dibromopropane, dibromomethane, 1,2-dibromoethane, 1,4-dibromobutane, 1,5-dibromopentane, 1,3-dichloropropane, and 1,3-diiodopropane.

[0022] In a preferred embodiment, in step S2, the molar ratio of the metallated cyclopentadiene to the halogenated alkyl compound is 1:(0.4-0.6).

[0023] In a preferred embodiment, in step S2, the conditions of the second reaction include: an inert gas atmosphere, a temperature of 0 to 10° C., and a time of 0.5 to 2 h.

[0024] In a preferred embodiment, in step S3, the molar ratio of the intermediate product I to metallic sodium is 1:(2.0-3.0).

[0025] In a preferred embodiment, in step S3, the conditions of the sodium reaction include: an inert gas atmosphere, a temperature of -50 to -30°C, and a time of 0.5 to 2 hours.

[0026] In a preferred embodiment, in step S4, the molar ratio of the intermediate product II to the hafnium halide is 1:(1.0-1.5).

[0027] In a preferred embodiment, in step S4, the conditions of the third reaction include: inert gas atmosphere, temperature of 0-10° C., and time of 2-6 h.

[0028] In a preferred embodiment, in step S5, the alkali metal alcohol compound is selected from at least one of sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, sodium tert-amylate, potassium methoxide, and potassium tert-butoxide.

[0029] In a preferred embodiment, in step S5, the alcohol compound is selected from at least one of methanol, ethanol, propanol, butanol, and tert-amyl alcohol.

[0030] In a preferred embodiment, in step S5, the molar ratio of the intermediate product III to the alkali metal compound and / or alcohol compound is 1:(2.0-3.0).

[0031] In a preferred embodiment, in step S5, the alkoxylation reaction of the intermediate product III with the alcohol compound further comprises carrying out the alkoxylation reaction in the presence of a basic catalyst.

[0032] In a preferred embodiment, in step S5, the alkoxylation reaction conditions include: an inert gas atmosphere and a reaction time of 1 to 4 hours.

[0033] In a preferred embodiment, the first organic solvent, the second organic solvent, the third organic solvent and the fourth organic solvent are each independently selected from at least one of tetrahydrofuran, DMF and dioxane.

[0034] In a preferred embodiment, the fifth organic solvent is selected from at least one of toluene, diethyl ether and xylene.

[0035] A third object of the present invention is to provide an application of the hafnium-based precursor material in a thin film deposition process.

[0036] Beneficial effects: The present invention designs and synthesizes a hafnium precursor material with a specific structure, and its molecular structure contains an organic group structure of alkylene dioctylene. Therefore, compared with the existing cyclopentadienyl hafnium precursor material ((such as cyclopentadienyl) tris(dimethylamino) hafnium), the hafnium precursor material has higher volatility and lower viscosity and improved film yield. The film obtained using this as the raw material has better quality and performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a thermogravimetric analysis result diagram of the hafnium precursor material H1 prepared in Example 1.

[0038] Figure 2 This is a thermogravimetric analysis result diagram of the hafnium precursor material H2 prepared in Example 2.

[0039] Figure 3 This is a thermogravimetric analysis result diagram of the hafnium precursor material H3 prepared in Example 3.

[0040] Figure 4 This is a thermogravimetric analysis result diagram of the hafnium precursor material H4 prepared in Example 4.

[0041] Figure 5 This is a thermogravimetric analysis result diagram of the hafnium precursor material H5 prepared in Example 5.

[0042] Figure 6 This is a thermogravimetric analysis result diagram of the hafnium precursor material H6 prepared in Example 6.

[0043] Figure 7 This is a graph showing the thermogravimetric analysis results of (cyclopentadienyl)tris(dimethylamino)hafnium in Comparative Example 1. DETAILED DESCRIPTION

[0044] The hafnium precursor material provided by the present invention has a structure as shown in formula (1):

[0045]

[0046] In formula (1), R1 is an alkylene group having 1 to 5 carbon atoms, and R2 and R3 are each independently an alkyl group having 1 to 5 carbon atoms. Among them, specific examples of alkylene groups having 1 to 5 carbon atoms include, but are not limited to, one of -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH(CH3)CH2-, -CH2CH2CH2CH2-, -CH(CH3)CH2CH2-, -CH2CH(CH3)CH2-, -C(CH3)2CH2-, -CH2CH2CH2CH2CH2-, -CH(CH3)CH2CH2CH2-, -CH2CH(CH3)CH2CH2-, -CH(CH2CH3)CH2CH2-, -CH2CH(CH2CH3)CH2-, -C(CH3)2CH2-, -CH2CH2CH2CH2CH2-, -CH(CH3)CH2CH2-, -CH2CH(CH2CH3)CH2-, -C(CH3)2CH2CH2-, and -CH2C(CH3)2CH2-, and preferably one of -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-. Specific examples of the alkyl group having 1 to 5 carbon atoms include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, and isopentyl.

[0047] In the present invention, the hafnium-based precursor material is preferably selected from at least one of the compounds having the structures represented by formulas (1-1) to (1-6):

[0048]

[0049]

[0050] The preparation method of the hafnium-based precursor material provided by the present invention comprises the following steps:

[0051] S1. performing a first reaction of cyclopentadiene with a metal hydride in the presence of a first organic solvent to obtain a metallated cyclopentadiene of formula (2);

[0052] S2. performing a second reaction of the metallated cyclopentadiene with the alkyl halide compound represented by formula (2) in the presence of a second organic solvent to obtain an intermediate product I represented by formula (3);

[0053] S3. The intermediate product Ⅰ is reacted with sodium metal in the presence of a third organic solvent to obtain an intermediate product Ⅱ shown in formula (4);

[0054] S4. performing a third reaction of the intermediate product II with a hafnium halide in the presence of a fourth organic solvent to obtain an intermediate product III represented by formula (5);

[0055] S5. alkoxylating the intermediate product III with an alkali metal alcohol compound and / or an alcohol compound in the presence of a fifth organic solvent to obtain a hafnium precursor material represented by formula (1);

[0056]

[0057] In formulas (2) to (6), Y is selected from at least one of sodium, potassium, lithium, calcium, and copper; R1 is an alkylene group having 1 to 5 carbon atoms; and X is selected from a chlorine atom, a bromine atom, and an iodine atom. Specific examples of the alkylene group having 1 to 5 carbon atoms are as described above and are not further described here. The hafnium halide is selected from at least one of hafnium tetrafluoride, hafnium tetrachloride, hafnium tetrabromide, and hafnium tetraiodide.

[0058] In the present invention, the first reaction, second reaction, sodiumization reaction, third reaction, and alkoxylation reaction are preferably carried out under anhydrous and oxygen-free conditions. Specifically, the anhydrous conditions can be achieved by requiring the reactor and raw materials to be dried. The oxygen-free conditions can be achieved by an inert gas atmosphere.

[0059] In the present invention, in step S1, specific examples of the metal hydride include but are not limited to at least one of sodium hydride, potassium hydride, calcium hydride, cuprous hydride, lithium aluminum hydride, and lithium hydride, and more preferably at least one of sodium hydride, potassium hydride, lithium hydride, and lithium aluminum hydride.

[0060] In the present invention, in step S1, the molar ratio of cyclopentadiene to metal hydride is preferably 1:(1.0-1.5), such as 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5 or any value therebetween.

[0061] In the present invention, in step S1, the conditions of the first reaction are not particularly limited, as long as cyclopentadiene can react with the metal hydride to obtain metallated cyclopentadiene. The reaction conditions may include but are not limited to: an inert gas atmosphere, such as nitrogen, argon, xenon, etc.; a temperature of -50 to -30°C, such as -50°C, -45°C, -40°C, -35°C, -30°C or any value therebetween; and a time of 0.5 to 2h, such as 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h, 2h or any value therebetween.

[0062] In the present invention, in step S2, the halogenated alkyl compound can be any compound having the structure of formula (2), and its specific type and source are not particularly limited. Specific examples of the halogenated alkyl compound include, but are not limited to, at least one of 1,3-dibromopropane, dibromomethane, 1,2-dibromoethane, 1,4-dibromobutane, 1,5-dibromopentane, 1,3-dichloropropane, and 1,3-diiodopropane.

[0063] In the present invention, in step S2, the molar ratio of the metallated cyclopentadiene to the halogenated alkyl compound is preferably 1:(0.4-0.6), such as 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6 or any value therebetween.

[0064] In the present invention, in step S2, the conditions of the second reaction are not particularly limited, as long as the metallated cyclopentadiene can react with the halogenated alkyl compound to obtain the intermediate product I shown in formula (3). The reaction conditions may include but are not limited to: an inert gas atmosphere, such as nitrogen, argon, xenon, etc.; a temperature of 0 to 10°C, such as 0°C, 2°C, 5°C, 8°C, 10°C or any value therebetween; and a time of 0.5 to 2h, such as 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h, 2h or any value therebetween.

[0065] In the present invention, in step S3, the molar ratio of the intermediate product I to metallic sodium is preferably 1:(2-3), such as 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3 or any value therebetween.

[0066] In the present invention, in step S3, the conditions of the sodiumization reaction are not particularly limited, as long as the intermediate product I can undergo a sodiumization reaction with metallic sodium to obtain the intermediate product II shown in (4). The reaction conditions may include but are not limited to: an inert gas atmosphere, such as nitrogen, argon, xenon, etc.; a temperature of -50 to -30°C, such as -50°C, -45°C, -40°C, -35°C, -30°C or any value therebetween; and a time of 0.5 to 2h, such as 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h, 2h or any value therebetween.

[0067] In the present invention, in step S4, the molar ratio of the intermediate product II to the hafnium halide is preferably 1:(1.0-1.5), such as 1:1.0, 1:1.2, 1:1.3, 1:1.4, 1:1.5 or any value therebetween.

[0068] In the present invention, in step S4, the conditions of the third reaction are not particularly limited, as long as the intermediate product II can react with the hafnium halide to obtain the intermediate product III shown in formula (5). The reaction conditions may include but are not limited to: an inert gas atmosphere, such as nitrogen, argon, xenon, etc.; a temperature of 0 to 10°C, such as 0°C, 2°C, 5°C, 8°C, 10°C or any value therebetween; and a time of 2 to 6h, such as 2h, 3h, 4h, 5h, 6h or any value therebetween.

[0069] In the present invention, in step S5, the alkali metal alcohol compound is a compound in which the H atom in the OH group of an alcohol is replaced by an alkali metal atom. Specific examples thereof include, but are not limited to, at least one of sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, sodium tert-amylate, potassium methoxide, and potassium tert-butoxide. Specific examples of the alcohol compound include, but are not limited to, at least one of methanol, ethanol, propanol, butanol, and tert-amyl alcohol.

[0070] In the present invention, in step S5, the molar ratio of the intermediate product III to the alkali metal compound and / or alcohol compound is preferably 1:(2.0-3.0), such as 1:2.0, 1:2.2, 1:2.5, 1:2.8, 1:3.0 or any value therebetween.

[0071] In the present invention, in step S5, the conditions of the alkoxylation reaction are not particularly limited, as long as the intermediate product III can undergo an alkoxylation reaction with the alkali metal alcohol compound to obtain the hafnium precursor material represented by formula (1). The reaction conditions may include but are not limited to: an inert gas atmosphere, such as nitrogen, argon, xenon, etc.; and a time of 1 to 4 hours, such as 1 hour, 2 hours, 3 hours, 4 hours or any value therebetween.

[0072] In the present invention, in step S5, the alkoxylation reaction of the intermediate product III with the alcohol compound is preferably carried out in the presence of a basic catalyst. The basic catalyst is a compound that can catalyze the reaction of the hydroxyl group of the alcohol compound with the intermediate product III to obtain the hafnium precursor material represented by formula (1). Specific examples thereof include, but are not limited to, at least one of triethylamine, N,N-dimethylaniline, and tripropylamine.

[0073] In the present invention, the type of the first organic solvent is not particularly limited, as long as it can provide favorable reaction medium environmental conditions for the reaction between cyclopentadiene and the metal hydride. The type of the second organic solvent is not particularly limited, as long as it can provide favorable reaction medium environmental conditions for the reaction between the alkali-metallated cyclopentadiene and the alkyl halide. The type of the third organic solvent is not particularly limited, as long as it can provide favorable reaction medium environmental conditions for the reaction between intermediate product I and sodium metal. The type of the fourth organic solvent is not particularly limited, as long as it can provide favorable reaction medium environmental conditions for the reaction between intermediate product II and hafnium tetrachloride. The type of the fifth organic solvent is not particularly limited, as long as it can provide favorable reaction medium environmental conditions for the reaction between intermediate product III and the alkali metal alcoholate. Specific examples of the first organic solvent, the second organic solvent, the third organic solvent, and the fourth organic solvent each independently include, but are not limited to, at least one of tetrahydrofuran, DMF, and dioxane. The fifth organic solvent is preferably selected from at least one of toluene, diethyl ether, and xylene.

[0074] In addition, the terms "first", "second", "third", "fourth", "fifth", "I", "II", and "III" are only for the purpose of convenience of description and do not mean any special limitation on the components and types.

[0075] The present invention will be described in detail below through specific examples. The examples of the embodiments are intended to explain the present invention and are not to be construed as limiting the present invention. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this field or the product specifications are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be obtained commercially.

[0076] Example 1

[0077] This example is used to illustrate the preparation of a hafnium-based precursor material. The specific process and synthesis route are as follows:

[0078] In an anhydrous and oxygen-free glove box, the experimental apparatus was set up using a dry three-necked flask. 150 g of dry tetrahydrofuran was added to the three-necked flask, which was cooled to -40°C. Cyclopentadiene (0.227 mol, 15 g) was added, maintaining the temperature at -40°C. NaH (0.238 mol, 5.72 g) was slowly added in five batches and stirred for 1 hour. The temperature was then raised to 0-5°C, and 1,3-dibromopropane (0.119 mol, 24.05 g) was slowly added. The reaction was stirred for 1 hour, and the temperature was returned to room temperature. The reaction solution was filtered using a dry sand core funnel to remove impurities. The system was then cooled to -40°C, sodium metal (0.238 mol, 5.48 g) was added to the system and stirred for 1 hour, then slowly heated to 0-5°C, hafnium tetrachloride (0.113 mol, 36.3 g) was added in batches, heated to reflux and stirred for 4 hours, then returned to room temperature, filtered using a sand core funnel (to remove impurities in the reaction solution), and then the solvent was removed by vacuum distillation to obtain the intermediate product III-1 (dichloro(trimethylenedicyclopentadienyl)hafnium), about 38.4 g, with a yield of about 80%. The H NMR spectrum of the intermediate product III-1 is as follows: 1 H NMR (400MHz, C6D6): (6.5, 4H; 6.4, 4H; 1.6, 2H; 1.3, 4H).

[0079] In an anhydrous and oxygen-free glove box environment, a dry three-necked flask was used to set up the experimental apparatus. At room temperature, 150 g of dry toluene was added to the three-necked flask, and dichloro(trimethylenebis(cyclopentadienyl)hafnium (0.0357 mol, 15 g) was added to the three-necked flask. After stirring evenly, sodium methoxide (0.0728 mol, 3.93 g) was slowly added. The mixture was stirred for 2 hours and filtered using a sand core funnel. The solvent was then removed by distillation under reduced pressure. The remaining material was purified by distillation at 0.1 torr and 100°C to obtain 10.6 g of white liquid with a yield of about 72.6%. The obtained white liquid was the hafnium precursor material, denoted as H1. It was identified by nuclear magnetic hydrogen spectrum and had the structure shown in formula (1-3). Nuclear magnetic hydrogen spectrum of hafnium precursor material H1 1 H NMR (400MHz, C6D6): (6.5, 4H; 6.4, 4H; 3.9, 6H; 1.6, 2H; 1.3, 4H).

[0080]

[0081] Example 2

[0082] This example is used to illustrate the preparation of a hafnium-based precursor material, and the specific process is as follows:

[0083] In an anhydrous and oxygen-free glove box environment, use a dry three-necked flask to set up the experimental apparatus. Add 150g of dry tetrahydrofuran to the three-necked flask, cool to -40°C, add cyclopentadiene (0.227mol, 15.00g) and maintain the temperature at -30°C. Slowly add NaH (0.340mol, 8.17g) in 5 batches and stir to react for 1h. Then raise the temperature to 0-5°C, slowly add dibromomethane (0.119mol, 20.68g) and stir to react for 1h. Return to room temperature and filter using a dry sand core funnel to remove impurities in the reaction solution. The system was then cooled to -30°C, sodium metal (0.340 mol, 7.82 g) was added to the system and stirred for 1 hour, then slowly heated to 5-10°C, hafnium tetrachloride (0.170 mol, 54.45 g) was added in batches, heated to reflux and stirred for 2 hours, then returned to room temperature, filtered using a sand core funnel (to remove impurities in the reaction solution), and then the solvent was distilled off under reduced pressure to obtain the intermediate product III-2 (dichloro(methylenedicyclopentadienyl)hafnium), about 34.46 g, with a yield of about 78%. The H NMR spectrum of the intermediate product III-2 1 H NMR (400MHz, C6D6): (6.5, 4H; 6.4, 4H; 1.4, 2H).

[0084] In an anhydrous and oxygen-free glove box environment, a dry three-necked flask was used to set up the experimental apparatus. At room temperature, 150 g of dry toluene was added to the three-necked flask, and dichloro(methylenebis(cyclopentadienyl)hafnium (0.0357 mol, 14.00 g) was added to the three-necked flask. After stirring evenly, sodium methoxide (0.0893 mol, 4.82 g) was slowly added. The mixture was stirred for 2 hours and filtered using a sand core funnel. The solvent was then removed by distillation under reduced pressure. The remaining material was purified by distillation at 0.1 torr and 100°C to obtain 9.5 g of a white liquid with a yield of about 70%. The obtained white liquid was the hafnium precursor material, denoted as H2. It was identified by nuclear magnetic hydrogen spectrum and had the structure shown in formula (1-1). Nuclear magnetic hydrogen spectrum of hafnium precursor material H2 1 H NMR (400MHz, C6D6): (6.5, 4H; 6.4, 4H; 3.9, 6H; 1.4, 2H).

[0085] Example 3

[0086] This example is used to illustrate the preparation of a hafnium-based precursor material, and the specific process is as follows:

[0087] In an anhydrous and oxygen-free glove box, the experimental apparatus was set up using a dry three-necked flask. 150 g of dry tetrahydrofuran was added to the three-necked flask, and the temperature was lowered to -40°C. Cyclopentadiene (0.227 mol, 15.00 g) was added, maintaining the temperature at -50°C. NaH (0.273 mol, 6.55 g) was slowly added in five batches and stirred for 2 hours. The temperature was then raised to 0-5°C, and 1,5-dibromopentane (0.119 mol, 27.36 g) was slowly added. The reaction was stirred for 2 hours, and the temperature was returned to room temperature. The reaction solution was filtered using a dry sand core funnel to remove impurities. The system was then cooled to -50°C, sodium metal (0.286 mol, 6.58 g) was added to the system and stirred for 2 hours, then slowly heated to 0-5°C, hafnium tetrachloride (0.136 mol, 43.56 g) was added in batches, heated to reflux and stirred for 6 hours, then returned to room temperature, filtered using a sand core funnel (to remove impurities in the reaction solution), and then the solvent was distilled off under reduced pressure to obtain the intermediate product III-3 (dichloro(pentamethylenedicyclopentadienyl)hafnium), about 35.88 g, with a yield of about 71%. The H NMR spectrum of the intermediate product III-3 is as follows: 1 H NMR (400MHz, C6D6): (6.5, 4H; 6.4, 4H; 1.32, 6H, 1.3, 4H).

[0088] In an anhydrous and oxygen-free glove box environment, a dry three-necked flask was used to set up the experimental apparatus. At room temperature, 150 g of dry toluene was added to the three-necked flask, and dichloro(pentamethylenebis(cyclopentadienyl)hafnium (0.0357 mol, 16.00 g) was added to the three-necked flask. After stirring evenly, sodium methoxide (0.0786 mol, 4.24 g) was slowly added. The mixture was stirred for 2 hours and filtered using a sand core funnel. The solvent was then removed by distillation under reduced pressure. The remaining material was purified by distillation at 0.1 torr and 100°C to obtain 11.03 g of white liquid with a yield of about 70.5%. The obtained white liquid was the hafnium precursor material, denoted as H3. It was identified by nuclear magnetic hydrogen spectrum and had the structure shown in formula (1-5). Nuclear magnetic hydrogen spectrum of hafnium precursor material H3 1 H NMR (400MHz, C6D6): (6.5, 4H; 6.4, 4H; 3.9, 6H; 1.32, 6H, 1.3, 4H).

[0089] Example 4

[0090] The hafnium precursor material was prepared according to the method of Example 1, except that the same mole of 1,2-dibromoethane was used instead of 1,3-dibromopropane to obtain the intermediate product III-4 (dichloro(dimethylenedioxadiazole)hafnium). The other conditions were the same as those in Example 1. Thus, the hafnium precursor material was prepared, which was recorded as H4. It was identified by nuclear magnetic hydrogen spectrum and had the structure shown in formula (1-2). Nuclear magnetic hydrogen spectrum of hafnium precursor material H4 1 HNMR (400MHz, C6D6): (6.5, 4H; 6.4, 4H; 3.9, 6H; 1.3, 4H).

[0091] Example 5

[0092] The hafnium precursor material was prepared according to the method of Example 1, except that the same mole of 1,4-dibromobutane was used instead of 1,3-dibromopropane to obtain the intermediate product III-5 (dichloro(tetramethylenediamine)hafnium). The other conditions were the same as those in Example 1. Thus, the hafnium precursor material was prepared, denoted as H5. It was identified by nuclear magnetic hydrogen spectrum and had the structure shown in formula (1-4). Nuclear magnetic hydrogen spectrum of hafnium precursor material H5 1 HNMR (400MHz, C6D6): (6.5, 4H; 6.4, 4H; 3.9, 6H; 1.6, 4H, 1.3, 4H).

[0093] Example 6

[0094] A hafnium precursor material was prepared according to the method of Example 1, except that the same mole of sodium propoxide was used instead of sodium methoxide. The other conditions were the same as those of Example 1. Thus, a hafnium precursor material was prepared, which was designated as H6. It was identified by H NMR spectrum and had the structure shown in formula (1-6). H NMR spectrum of hafnium precursor material H6 1 H NMR (400MHz, C6D6): (6.5, 4H; 6.4, 4H; 3.51, 5H; 1.6, 2H; 1.51, 4H; 1.3, 4H; 0.99, 6H).

[0095] Example 7

[0096] A hafnium precursor material was prepared according to the method of Example 1, except that the prepared intermediate product III-1 (dichloro(trimethylenedicyclopentadienyl)hafnium) (0.0357 mol) was mixed with methanol (0.0728 mol) and triethylamine (0.0728 mol) and stirred for reaction. The remaining conditions were the same as those in Example 1, thereby preparing a hafnium precursor material, denoted as H7, which was identified by nuclear magnetic hydrogen spectrum and had the structure shown in formula (1-3).

[0097] Comparative Example 1

[0098] (Cyclopentadienyl)tris(dimethylamino)hafnium, CAS: 941596-80-1, was purchased from Shanghai Jizhi Biochemical Technology Co., Ltd.

[0099] Comparative Example 2

[0100] A reference hafnium precursor material was prepared according to the method of Example 1, except that the same mole of sodium methylate (CH3N) was used instead of sodium methoxide. The other conditions were the same as those in Example 1. A reference hafnium precursor material was thus prepared, denoted as DH1, and was identified by H NMR spectroscopy to have the structure shown in formula (1-7).

[0101]

[0102] Test Case

[0103] The hafnium-based precursor materials of the above examples and comparative examples were tested according to the following method.

[0104] (1) Thermal stability test: The thermal stability of hafnium precursor materials was tested using a TGA 550 thermogravimetric instrument. The results are as follows: Figures 1 to 7 As shown, within 250°C, the volatility of the hafnium precursor materials of Examples 1 to 7 reached 99.846%, 99.953%, 99.886%, 99.940%, 99.960%, 99.655% and 99.951%, respectively, while that of Comparative Example 1 reached 98.050% within 250°C, and that of Comparative Example 2 reached 98.774% within 250°C, indicating that the hafnium precursor material provided by the present invention has good volatility.

[0105] (2) Viscosity Test: The viscosity of the hafnium precursor material was tested using an Anton Paar SVM 2001 kinematic viscometer. The test conditions were: measurement cell temperature 25°C, shear rate 583±1 l / s, and shear force 5±0.005 Pa. The results are shown in Table 1.

[0106] (3) Film yield and hafnium oxide film metal purity test:

[0107] Metal testing equipment: ICP-MS NexION 2000s, platinum sampling cone, test conditions: nebulizer flow rate: 0.86 L / min, oxygen AMS gas flow rate: 0.05 L / min. Metal purity was assessed based on the ICP-MS test results of each Example and Comparative Example: Metal purity of the hafnium oxide film = (1 - sum of all metal contents excluding Hf) * 100%, with "6N" indicating a purity of 99.9999%. The results are shown in Table 1, with the ICP-MS test results for Example 1 shown in Table 2.

[0108] Film yield: Place the reaction substrate in the PE-MOCVD equipment, set the deposition temperature to 250°C, inject the hafnium precursor material and nitrogen gas onto the substrate of the reaction chamber, introduce oxygen plasma into the reaction chamber, react with the product to form hafnium oxide deposited on the substrate, and introduce nitrogen gas again after the oxide layer is formed to remove the unreacted precursor material and by-products. Repeat this deposition step 4 times to obtain a hafnium oxide film on the substrate. Observe under a microscope and use an ellipsometer to measure the actual thickness of the deposited hafnium oxide film when the film coverage is 100%, which is recorded as d 实际 , according to formula d 理论 =m / (ρ Hf *S)=n*M Hf / (ρ Hf *S) Calculate theoretical thickness d 理论 , where M Hf is the molar mass of the hafnium precursor material, S is the deposition area, ρ Hf is the density of the hafnium oxide film. Then according to the formula Yd=d 实际 / d 理论 *100% was used to calculate the membrane yield Yd. The results are shown in Table 1.

[0109] Table 1

[0110] Viscosity (mPa·s) Membrane yield Yd ​​(%) Metal purity Example 1 8.58 99 6N Example 2 8.55 98 6N Example 3 8.57 99 6N Example 4 8.55 97 6N Example 5 8.54 99 6N Example 6 8.56 99 6N Example 7 8.61 99 6N Comparative Example 1 11.23 93 6N Comparative Example 2 10.30 95 6N

[0111] Table 2

[0112]

[0113]

[0114] From the results in Table 1, it can be seen that compared with Comparative Examples 1 and 2, the hafnium-based precursor materials provided by Examples 1 to 7 of the present invention have lower viscosity, and the hafnium oxide film prepared using the hafnium-based precursor materials has a higher film yield and high metal purity.

[0115] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A hafnium-based precursor material, characterized in that: The hafnium-based precursor material has a structure as shown in formula (1): In formula (1), R1 is an alkylene group having 1 to 5 carbon atoms, and R2 and R3 are each independently an alkyl group having 1 to 5 carbon atoms.

2. The hafnium-based precursor material according to claim 1, characterized in that: The hafnium precursor material is selected from at least one of the compounds having the structures shown in formulas (1-1) to (1-6):

3. The method for preparing the hafnium-based precursor material according to claim 1 or 2, characterized in that: The preparation method comprises the following steps: S1. performing a first reaction of cyclopentadiene with a metal hydride in the presence of a first organic solvent to obtain a metallated cyclopentadiene of formula (2); S2. performing a second reaction of the metallated cyclopentadiene with the alkyl halide compound represented by formula (3) in the presence of a second organic solvent to obtain an intermediate product I represented by formula (4); S3. The intermediate product Ⅰ is reacted with sodium metal in the presence of a third organic solvent to obtain an intermediate product Ⅱ shown in formula (5); S4. performing a third reaction of the intermediate product II with a hafnium halide in the presence of a fourth organic solvent to obtain an intermediate product III represented by formula (6); S5. alkoxylating the intermediate product III with an alkali metal alcohol compound and / or an alcohol compound in the presence of a fifth organic solvent to obtain a hafnium precursor material represented by formula (1); In formulas (2) to (6), Y is selected from at least one of sodium, potassium, lithium, calcium, and copper, R1 is an alkylene group having 1 to 5 carbon atoms, and X is selected from a chlorine atom, a bromine atom, and an iodine atom; The hafnium halide is at least one selected from hafnium tetrafluoride, hafnium tetrachloride, hafnium tetrabromide, and hafnium tetraiodide.

4. The method for preparing the hafnium-based precursor material according to claim 3, wherein: In step S1, the metal hydride is selected from at least one of sodium hydride, potassium hydride, lithium hydride, and lithium aluminum hydride; Preferably, the molar ratio of cyclopentadiene to metal hydride is 1:(1.0-1.5); Preferably, the conditions of the first reaction include: an inert gas atmosphere, a temperature of -50 to -30°C, and a time of 0.5 to 2 hours.

5. The method for preparing the hafnium-based precursor material according to claim 3, wherein: In step S2, the halogenated alkyl compound is selected from at least one of 1,3-dibromopropane, dibromomethane, 1,2-dibromoethane, 1,4-dibromobutane, 1,5-dibromopentane, 1,3-dichloropropane, and 1,3-diiodopropane; Preferably, the molar ratio of the metallated cyclopentadiene to the halogenated alkyl compound is 1:(0.4-0.6); Preferably, the conditions of the second reaction include: an inert gas atmosphere, a temperature of 0 to 10° C., and a time of 0.5 to 2 h.

6. The method for preparing the hafnium-based precursor material according to claim 3, wherein: In step S3, the molar ratio of the intermediate product I to metallic sodium is 1:(2.0-3.0); Preferably, the conditions for the sodiumization reaction include: an inert gas atmosphere, a temperature of -50 to -30°C, and a time of 0.5 to 2 hours.

7. The method for preparing the hafnium-based precursor material according to claim 3, wherein: In step S4, the molar ratio of the intermediate product II to the hafnium halide is 1:(1.0-1.5); Preferably, the conditions of the third reaction include: an inert gas atmosphere, a temperature of 0 to 10° C., and a time of 2 to 6 hours.

8. The method for preparing the hafnium-based precursor material according to claim 3, wherein: In step S5, the alkali metal alcohol compound is selected from at least one of sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, sodium tert-amylate, potassium methoxide, and potassium tert-butoxide; Preferably, the alcohol compound is selected from at least one of methanol, ethanol, propanol, butanol, and tert-amyl alcohol; Preferably, the molar ratio of the intermediate product III to the alkali metal compound and / or alcohol compound is 1:(2.0-3.0); Preferably, the alkoxylation reaction of the intermediate product III with the alcohol compound further comprises being carried out in the presence of a basic catalyst; Preferably, the alkoxylation reaction conditions include: an inert gas atmosphere and a reaction time of 1 to 4 hours.

9. The method for preparing the hafnium-based precursor material according to claim 3, wherein: The first organic solvent, the second organic solvent, the third organic solvent and the fourth organic solvent are each independently selected from at least one of tetrahydrofuran, DMF and dioxane; Preferably, the fifth organic solvent is selected from at least one of toluene, diethyl ether and xylene.

10. Use of the hafnium-based precursor material according to claim 1 or 2 in a thin film deposition process.

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