Preparation method and deposition method of IVB group metal organic precursor

Abstract

The invention provides a preparation method of an IVB group metal organic precursor, which comprises the following steps: treating an amine ligand into corresponding lithium amide by using n-butyllithium before use, reacting IVB group metal chloride with the lithium amide, obtaining an amine group metal organic precursor mixed solution after the reaction is ended, discharging residual gas, filtering, desolventizing, and carrying out reduced pressure distillation to obtain the IVB group metal organic precursor. The amino metal organic precursor is obtained. The invention further discloses a deposition method of the IVB group metal organic precursor. The deposition method comprises the following step of performing thin film deposition on the prepared amino metal organic precursor, the prepared cyclopentadienyl metal organic precursor and an oxygen source to prepare a metal oxide thin film. The reaction is promoted by adjusting the use amount of alkylamine, the use amount of a toluene solvent is reduced, and then the alkylamine is applied to a corresponding oxide thin film deposition process. The process has the advantages of good safety and high economical efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of precursor preparation and deposition, and in particular to a method for preparing and depositing a group IVB metal organic precursor. Background Art

[0002] Capacitors are one of the key components in dynamic random access memory (DRAM) technology. As device feature sizes decrease, traditional SiO2 gate dielectric materials are difficult to meet the device stability requirements of the microelectronics industry. High dielectric constant materials (high-K materials) replace traditional SiO2 gate dielectric layers and capacitor dielectrics, increase the equivalent thickness of the dielectric layer and reduce the tunneling effect, which is an effective technical means to improve the stability of electronic devices. As a substitute for silicon dioxide, zirconium oxide (23.2~24.6) and hafnium oxide (23.3~24.7) have the characteristics of high dielectric constants and high thermal stability, and have been used as High-k materials in industrial sites.

[0003] The synthesis process of IVB group metal organic precursors for TDMAZ, TDMAH, TDMAT, TEMAZ, TEMAH, CpZr, and CpHf is as follows:

[0004] ①HNR1R2+LiC4H9=LiNR1R2+C4H 10

[0005] ②LiNR1R2+MCl4=M(NR1R2)4+4LiCl

[0006] ③M(NR1R2)4+Cp=Cp M(NR1R2)3+HNR1R2

[0007] The intermediate product LiNR1R2 in reaction ① is insoluble in the solvent n-hexane, and the raw material MCl4 in reaction ② is also solid, which makes the reaction impossible. To solve this problem, toluene solvent is usually added to promote the reaction, but this solution has the following problems: (1) Toluene is easy to make drugs, which increases the risk of the reaction, and this product is a controlled product and its purchase is subject to legal restrictions; (2) Adding a new solvent to the reaction increases the volume of the reaction equipment, and after the reaction is completed, a solvent separation system needs to be added to achieve solvent recycling, which increases equipment investment. Summary of the invention

[0008] The present invention provides a preparation method and a deposition method based on a novel precursor material, which are applied to the deposition of corresponding oxide thin films, and then zirconium oxide, hafnium oxide and titanium oxide thin films are prepared by ALD technology. The present invention promotes the reaction by adjusting the amount of alkylamine used, reduces the use of toluene solvent, and then uses it in the corresponding oxide thin film deposition process. The process has the advantages of good safety and high economy.

[0009] The technical solution adopted by the present invention is:

[0010] A method for preparing an IVB group metal organic precursor comprises the following steps: treating an amine ligand with n-butyl lithium before use to obtain a corresponding lithium amide, reacting an IVB group metal chloride with the lithium amide, obtaining an organic metal amide precursor mixed solution after the reaction is completed, discharging residual gas, filtering, desolventizing, and distilling under reduced pressure to obtain an organic metal amide precursor.

[0011] Preferably, the method for preparing lithium amide is as follows: n-butyl lithium is dissolved in n-hexane to form an n-butyl lithium-n-hexane solution, an amine ligand is introduced into the n-butyl lithium-n-hexane solution, and the reaction is carried out at a temperature of -20 to -10°C for 7 to 9 hours; the mass concentration of n-butyl lithium in the n-butyl lithium-n-hexane solution is 5% to 20%;

[0012] The mass ratio of n-butyl lithium: amine ligand is 1.0: 1.0-1.5.

[0013] Preferably, the Group IVB metal chloride reacts with lithium amide, and the amine ligand is continuously introduced during the reaction. The reaction temperature is -20 to 80°C, the pressure is 0 to 0.3 MPa, and the time is 22 to 26 hours. The mass ratio of the amine ligand continuously introduced to the mass ratio of the amine ligand used to generate the lithium amide is 1:0.9-1.

[0014] Preferably, the amine ligand used is dimethylamine, methylethylamine or diethylamine;

[0015] The IVB group metal chloride includes ZrCl4, HfCl4 and TiCl4, and the mass ratio of the IVB group metal chloride to lithium amide is 1.0:4.0-10.0;

[0016] The obtained amino metal organic precursors include tetrakis(dimethylamino)zirconium TDMAZ, tetrakis(dimethylamino)hafnium TDMAH, tetrakis(dimethylamino)titanium TDMAT, tetrakis(methylethylamino)hafnium TEMAH, tetrakis(methylethylamino)zirconium TEMAZ, tetrakis(methylethylamino)titanium TEMAT, tris(dimethylamino)hafnium TDEAH, tris(dimethylamino)zirconium TDEAZ and tris(dimethylamino)titanium TDEAT.

[0017] Preferably, the desolventizing pressure is -0.080 to -0.095 MPa and the temperature is 55 to 65°C;

[0018] During the vacuum distillation process, the pressure of the vacuum distillation is 0.1-2 mmHg and the temperature is 50-100°C.

[0019] Preferably, the method further comprises reacting a mixed solution of cyclopentadiene and an amino metal organic precursor, filtering, desolventizing, and distilling under reduced pressure to obtain a cyclopentadiene metal organic precursor after the reaction is completed;

[0020] The reaction temperature is -20 to 80°C and the reaction time is 20 to 24 hours;

[0021] The molar ratio of cyclopentadiene to the amino metal organic precursor is 1-1.05:1;

[0022] The desolventizing pressure is -0.080 to -0.095 MPa, and the temperature is 55 to 65°C;

[0023] The pressure of vacuum distillation is 0.1-2 mmHg and the temperature is 50-100°C;

[0024] The cyclopentadienyl metal organic precursor includes (cyclopentadienyl) tris(dimethylamino) zirconium CpZr, (cyclopentadienyl) tris(dimethylamino) hafnium CpHf and (cyclopentadienyl) tris(dimethylamino) titanium CpTi.

[0025] A group IVB metal organic precursor deposition method uses a precursor prepared by a group IVB metal organic precursor preparation method to deposit an oxide film, comprising the following steps: preparing a metal oxide film by film deposition using the prepared amino metal organic precursor and cyclopentadienyl metal organic precursor and an oxygen source.

[0026] Preferably, the specific process is: injecting an amine metal organic precursor and a cyclopentadienyl metal organic precursor material into an atomic layer deposition reactor to perform a pulse purge operation, and depositing an oxide film on a pre-cleaned silicon substrate;

[0027] The oxygen source includes ozone.

[0028] Preferably, the deposition temperature in the atomic layer deposition reactor is in the range of 200° C. to 400° C., and the pressure in the atomic layer deposition reactor is maintained at 500 mtorr to 1 torr.

[0029] Preferably, the pulse purging operation includes, in sequence: pulsing with the vapor of the aminometallic organic precursor or the cyclopentadienylmetallic organic precursor for 5 seconds, purging with argon for 10 seconds, pulsing with the oxygen source for 5 seconds, and purging with argon for 10 seconds.

[0030] The present invention has the following beneficial effects:

[0031] The present invention increases the solubility of lithium amide and reduces the reaction diffusion resistance to prepare the IVB group metal organic precursor, and effectively applies it to the atomic layer deposition (ALD) process for preparing zirconium oxide, hafnium oxide and titanium oxide thin films.

[0032] (1) Eliminate the use of toluene, a chemical that is easy to make drugs, improve process safety, and reduce the difficulty of raw material procurement;

[0033] (2) Reduce the volume of the reaction equipment and simplify the solvent separation system, thereby realizing solvent recycling and reducing equipment investment. DETAILED DESCRIPTION

[0034] The present invention is further explained below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0035] Embodiment 1

[0036] Preparation of amino metal organic precursors:

[0037] S1: 50.0 g of dimethylamine was introduced into 427 g of a commercially available 1.6 M n-butyl lithium-n-hexane solution, and additional n-hexane was added to adjust the mass concentration to 10%, followed by reaction for 8 hours to obtain a milky white lithium dimethylamine suspension, and the reaction temperature was -20 to -10°C;

[0038] Add 60.0 g of zirconium tetrachloride to the above suspension, continue to introduce 50.0 g of dimethylamine, and then continue to react at 20-30° C. for 24 hours, with the reaction pressure controlled within 0.1 MPa;

[0039] After the reaction, the residual gas was discharged, filtered, and distilled and desolventized at -0.080 to -0.095 MPa, 60°C, 1 mmHg, and 80°C under reduced pressure to obtain 46.8 g of light yellow crystalline particles.

[0040] NMR 1 H NMR (C6D6) test result: δ2.92 (s, 18H).

[0041] Deposition of Amino Metal Organic Precursors:

[0042] S2: Inject the precursor material TDMAZ synthesized in step S1 into the ALD reactor, control the deposition temperature range in the ALD reactor to be 300°C, and maintain the pressure in the ALD reactor at 500 mtorr. The purging operation includes: pulsing with precursor vapor for 5S, purging with argon for 10S, pulsing with ozone for 5S, and purging with argon for 10S. A zirconium oxide film is deposited on the pre-cleaned silicon substrate.

[0043] Embodiment 2

[0044] Preparation of amino metal organic precursors:

[0045] S1: 60.0 g of methylethylamine was added to 280.0 g of a commercially available 2.5 M n-butyllithium-n-hexane solution, and additional n-hexane was added to adjust the mass concentration to 5%, followed by a reaction for 7 hours to obtain a milky white methylethylamine lithium suspension, and the reaction temperature was -20 to -10°C;

[0046] Add 80.0 g of hafnium tetrachloride to the above suspension, and then continue to add 60.0 g of methylethylamine, and then continue to react at 50-80° C. for 26 hours, and the reaction pressure is controlled within 0.3 MPa;

[0047] After the reaction is completed, the residual gas is discharged, filtered, and distilled and desolventized at -0.080 to -0.095 MPa, 65°C, 0.1 mmHg, and 50°C under reduced pressure to obtain 61.6 g of light yellow liquid.

[0048] NMR 1 H NMR (C6D6) test result: δ2.90 (s, 18H).

[0049] Deposition of Amino Metal Organic Precursors:

[0050] S2: Inject the precursor material TEMAH synthesized in step S1 into the ALD reactor, control the deposition temperature range in the ALD reactor to be 200°C, and maintain the pressure in the ALD reactor at 1 torr. The purging operation includes: pulsing with precursor vapor for 5S, purging with argon for 10S, pulsing with ozone for 5S, and purging with argon for 10S. A hafnium oxide film is deposited on the pre-cleaned silicon substrate.

[0051] Embodiment 3

[0052] Preparation of cyclopentadienyl metal organic precursors:

[0053] S1: 90.0 g of dimethylamine was introduced into 860.0 g of a commercially available 1.6 M n-butyl lithium-n-hexane solution, and additional n-hexane was added to adjust the mass concentration to 20%, followed by a reaction for 9 hours to obtain a milky white lithium dimethylamine suspension, and the reaction temperature was -20 to -10°C;

[0054] 116.5 g of zirconium tetrachloride was added to the suspension, and 100.0 g of dimethylamine was continuously introduced, and then the reaction was continued at -20 to 10° C. for 22 hours, and the reaction pressure was controlled within 0.2 MPa; after the reaction was completed, 33.0 g of cyclopentadiene was added dropwise, and the reaction was continued at 30° C. for 24 hours;

[0055] After the reaction, the residual gas was discharged, filtered, and distilled and desolventized at 55°C at -0.080 to -0.095 MPa, 2 mmHg, and 100°C under reduced pressure to obtain 70.5 g of a light yellow liquid.

[0056] NMR 1 H NMR (C6D6) test results: δ6.06 (s, 4H), 2.92 (s, 18H).

[0057] Deposition of cyclopentadienyl metal organic precursors:

[0058] S2: Inject the precursor material CpZr(N(CH3)2)3 synthesized in step S1 into the ALD reactor, control the deposition temperature range in the ALD reactor to 400°C, and maintain the pressure in the ALD reactor at 500 mtorr. The purging operation includes: pulsing with precursor vapor for 5S, purging with argon for 10S, pulsing with ozone for 5S, and purging with argon for 10S. The zirconide film is deposited on the pre-cleaned silicon substrate.

[0059] Embodiment 4

[0060] Preparation of cyclopentadienyl metal organic precursors:

[0061] S1: 90.0 g of dimethylamine was introduced into 860.0 g of a commercially available 1.6 M n-butyl lithium-n-hexane solution, and additional n-hexane was added to adjust the mass concentration to 20%, followed by a reaction for 9 hours to obtain a milky white lithium dimethylamine suspension, and the reaction temperature was -20 to -10°C;

[0062] Add 90.0 g of titanium tetrachloride to the above suspension, continue to introduce 100.0 g of dimethylamine, and then continue to react at -20 to 10° C. for 22 hours, with the reaction pressure controlled within 0.2 MPa; after the reaction is completed, add 33.0 g of cyclopentadiene dropwise, and continue to react at 80° C. for 20 hours;

[0063] After the reaction, the residual gas was discharged, filtered, and distilled and desolventized at -0.080 to -0.095 MPa, 55°C, 2 mmHg, and 100°C under reduced pressure to obtain 54.5 g of light yellow liquid.

[0064] NMR 1 H NMR (C6D6) test results: δ 6.05 (s, 4H), 2.91 (s, 18H).

[0065] Deposition of cyclopentadienyl metal organic precursors:

[0066] S2: Inject the precursor material CpTi(N(CH3)2)3 synthesized in step S1 into the ALD reactor, control the deposition temperature range in the ALD reactor to 400°C, and maintain the pressure in the ALD reactor at 500 mtorr. The purging operation includes: pulsing with precursor vapor for 5S, purging with argon for 10S, pulsing with ozone for 5S, and purging with argon for 10S. The zirconide film is deposited on the pre-cleaned silicon substrate.

[0067] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a group IVB metal organic precursor, characterized in that: The following steps are involved: The amine ligand is treated with n-butyl lithium to obtain the corresponding lithium amide before use. The Group IVB metal chloride reacts with the lithium amide. After the reaction is completed, an organic metal amide precursor mixed solution is obtained. The residual gas is discharged, filtered, desolventized, and distilled under reduced pressure to obtain an organic metal amide precursor.

2. The method for preparing a Group IVB metal organic precursor according to claim 1, characterized in that: The preparation method of lithium amide is as follows: n-butyl lithium is dissolved in n-hexane to form n-butyl lithium-n-hexane solution, and an amine ligand is introduced into the n-butyl lithium-n-hexane solution, and reacted at a temperature of -20 to -10°C for 7 to 9 hours; The mass concentration of n-butyl lithium in the n-butyl lithium-n-hexane solution is 5% to 20%; The mass ratio of n-butyl lithium: amine ligand is 1.0:1.0-1.

5.

3. The method for preparing a Group IVB metal organic precursor according to claim 1, characterized in that: The IVB group metal chloride reacts with lithium amide, and the amine ligand is continuously introduced during the reaction. The reaction temperature is -20 to 80°C, the pressure is 0 to 0.3 MPa, and the reaction time is 22 to 26 hours. The mass ratio of the amine ligand continuously introduced to the mass ratio of the amine ligand used to generate the lithium amide is 1:0.9-1.

4. The method for preparing a Group IVB metal organic precursor according to claim 1, characterized in that: The amine ligand used is dimethylamine, methylethylamine or diethylamine; The IVB group metal chloride is ZrCl4, HfCl4 and TiCl4, and the mass ratio of the IVB group metal chloride to lithium amide is 1.0:4.0-10.0; The obtained amino metal organic precursors include tetrakis(dimethylamino)zirconium TDMAZ, tetrakis(dimethylamino)hafnium TDMAH, tetrakis(dimethylamino)titanium TDMAT, tetrakis(methylethylamino)hafnium TEMAH, tetrakis(methylethylamino)zirconium TEMAZ, tetrakis(methylethylamino)titanium TEMAT, tris(dimethylamino)hafnium TDEAH, tris(dimethylamino)zirconium TDEAZ and tris(dimethylamino)titanium TDEAT.

5. The method for preparing a Group IVB metal organic precursor according to claim 1, characterized in that: The desolventizing pressure is -0.080 to -0.095 MPa, and the temperature is 55 to 65°C; During the vacuum distillation process, the pressure of the vacuum distillation is 0.1-2 mmHg and the temperature is 50-100°C.

6. The method for preparing a Group IVB metal organic precursor according to claim 1, characterized in that: The method also includes reacting a mixed solution of cyclopentadiene and an amino metal organic precursor, filtering, desolventizing, and distilling under reduced pressure to obtain a cyclopentadiene metal organic precursor after the reaction is completed; The reaction temperature is -20 to 80°C and the reaction time is 20 to 24 hours; The molar ratio of cyclopentadiene to the amino metal organic precursor is 1-1.05:1; The desolventizing pressure is -0.080 to -0.095 MPa, and the temperature is 55 to 65°C; The pressure of vacuum distillation is 0.1-2 mmHg and the temperature is 50-100°C; The cyclopentadienyl metal organic precursor includes (cyclopentadienyl) tris(dimethylamino) zirconium CpZr, (cyclopentadienyl) tris(dimethylamino) hafnium CpHf and (cyclopentadienyl) tris(dimethylamino) titanium CpTi.

7. A method for depositing a Group IVB metal organic precursor, using a precursor prepared by the method for preparing a Group IVB metal organic precursor according to claims 1 to 6 to deposit an oxide thin film, characterized in that: The following steps are involved: The prepared amino metal organic precursor and cyclopentadienyl metal organic precursor are used with an oxygen source to carry out thin film deposition to prepare a metal oxide film.

8. A method for depositing a Group IVB metal organic precursor according to claim 7, characterized in that: The specific process is as follows: an amine-based metal organic precursor and a cyclopentadienyl metal organic precursor material are injected into an atomic layer deposition reactor to perform a pulse purge operation, and an oxide film is deposited on a pre-cleaned silicon substrate; The oxygen source includes ozone.

9. A method for depositing a Group IVB metal organic precursor according to claim 8, characterized in that: The deposition temperature in the atomic layer deposition reactor is 200-400° C., and the pressure in the atomic layer deposition reactor is maintained at 500 mtorr-1 torr.

10. The method for depositing a Group IVB metal organic precursor according to claim 8, characterized in that: The pulse purging operation sequentially includes: pulsing with the vapor of the aminometallic organic precursor or the cyclopentadienylmetallic organic precursor for 5 seconds, purging with argon for 10 seconds, pulsing with the oxygen source for 5 seconds, and purging with argon for 10 seconds.